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[Question] [ Following this question: [How can I implement time travel on a somewhat realistic way?](https://worldbuilding.stackexchange.com/questions/200484/how-can-i-implement-time-travel-on-a-somewhat-realistic-way) Considering I have a way of getting energy into the past (as said on the previous question), I need a way of storing energy (or anything that can store data) until 300 million years later, as this would work as communications. You don’t need to work about paradoxes. Assume that the sender and receiver know the communication system used. So, how can I store energy/data reliably for 300 mil years (1 terabyte)? Requirements: * you can use unproved tech, but the answers closer to modern day tech will be preferred over normal ones. * method Is bound by gravity (so keeps around the same star). besides that you can do whatever you want for your answer [Answer] You come from the future, therefore you know there is still life. Encode your information into the mitochondrial DNA of species you know will have living descendants in the epoch where you want to send the message. Mitochondrial DNA is carried along from only one of the two parents, so it doesn't get mixed with sexual reproduction. Even though random mutation can happen, with a large enough sample the receiver can statistically reconstruct the original message. [Answer] Quartz crystal memory discs will easily last the 300 million years required and already exist as a product. [Quartz memory discs](https://techstartups.com/2020/02/22/eternal-5d-optical-data-storage-quartz-disc-can-store-360-terabytes-data-13-8-billion-years/) But remember there's a difference between storing the information and then being able to access and read it at some unspecified time the remote future. You need the reading technology to last as well. So you may prefer to etch the design of the laser/reader into metal tablets and put both the discs (which can hold a huge amount of data) and the tablets in the vacuum of space. Preferably in an asteroid in a stable orbit. Addendum: Alternately you could I suppose place readers and a sample power source for them alongside the plates in the asteroid. They may not last but at least whoever recovers them can take them apart and compare them to the diagrams on the plates to build a working copy. Energy is much harder - the only energy source that would last the time required without complex technology would be potential energy. Which the asteroid would have if diverted at the appropriate time into the appropriate orbit. And if that's difficult just store everything on the moon as someone else has suggested. [Answer] ### Put it on the Moon. The Moon is a nearly unchanging environment, without geological or atmospheric variations over time that might damage your system. The only thing you'd really need to worry about are meteor impacts, and you can account for this by simply taking a map of the Moon from the future, comparing it to the map you've taken of the Moon in the past, and then placing your cache within a crater that has survived unchanged between those two epochs. Unlike asteroids and other smaller bodies in the Solar System, the Moon is gravitationally locked to the Earth, so you won't need to worry about losing it 300 million years later. [Answer] Storing data in energy for 300 million years is trivial. We are receiving data that was sent just after the creation of the universe. We are talking billions of years, not millions, that this data has lasted. The data is so intact that we are still able to get an abundance of information from it. The only 'coding' necessary is the natural 'coding' of information and data inherent in physics and cosmology. A powerful enough laser beam of light, encoded with data, projected from within our solar system by a strong enough source, will survive for billions of years. In fact, there is a great portion of the EM spectrum that one could use. The bit rate, however, would probably not be in bps but more like bits per hours or days. A slow minutes-long or hours-long blinking. However, once sent, there would be no way humans could have ever modified or interfered with it. It would be, as far as we are concerned with our current technology, hack-proof. No encryption necessary. It could even be sent in analog form, but there would be losses of information and error correction is complicated. Being able to catch UP to that light in order to read it, is another thing. One would presumably have to travel FTL. But there IS a way to get it to 'come back' to us without us going after it. Aim it at a huge galactic-sized 'mirror' or 'reflector' 150 million light years away, and read the reflected data 150 million years later. How that reflector gets there, whether it is human-made, purpose-built, a natural formation, or whatever seems to fall into the category of 'can do whatever you want for your answer'. Of course, it would have to be well timed, and aimed at where the reflector is GOING to be in 150 million years, and the return reflected signal aimed at where the solar system is going to be 300 million years later, but it would be 'stored' for 300 million years, as required. And it is well within technology levels today, given the dedication of enough resources. Absolutely nothing about it that is not within the current bounds of conventional physics thinking. The technology for receiving it is already readily available. We have plenty of telescopes and receivers that would suffice. Even SETI could pick it up. But, well, blink and you miss it. Addendum Edit @dhinson919 suggested an intriguing idea. By the correct positioning of black holes, dark matter, and such, use them as a gravitational lens to focus and direct an EM signal through the universe, much like we use fiber optic cable to channel laser beams. Using space itself as a storage media, the possibilities for storage are immense. [Answer] Use a physical storage system, in a very inert material. Something like a gold platter. It must be completely chemically and radiologically inert. Store it with massive internal errorchecking and redundancy, so that minor scratches or holes will not invalidate your data. Store it in a location that is unlikely to be disturbed over the requisite timespan. Places like buried in a mine, on a tectonically boring continent. But that might be hard to find later. How about buried under a landmark crater on the Moon? Or on a known asteroid? Unfortunately 300 million years is long enough that no possible free-space orbit is going to be sufficiently predictable, even a Pluto-sized heliocentric orbit will have deviated beyond accurate prediction. But most importantly: Redundancy. You want to store your data on many, many,many different locations. Inevitably some of them will have been destroyed, gotten themselves eaten, damaged by meteors, stolen by cavemen and turned into earrings, or spontaneously combusted. Who knows what could go wrong? As for storing energy, with sufficient accuracy to retain data? Not a chance! Not in one location, at least. You could always beam the datastream out, but the receiver would need to be 300 million lightyears away from the source, which might be inconvenient! [Answer] This is the stratigraphy of the [Grand Canyon](https://en.wikipedia.org/wiki/Grand_Canyon) [![Grand Canyon stratigraphy](https://i.stack.imgur.com/TR6Mr.jpg)](https://i.stack.imgur.com/TR6Mr.jpg) As you can see it goes back to 500 million years ago, and it's basically a very large bar code. Just encode the proper layering along the path of the Grand Canyon, and your message will be kindly exposed by the natural agents when the time is due. [Answer] ## 300 Million Years is too long to trust any location or passive storage medium Rocks could fall from the sky. The ground beneath your facility (on a geologically active world) could be subducted into magma. Celestial bodies could plunge into their parent stars! You're going to need to design something intelligent, basically immortal, and mobile. Something smart enough, with good enough observational capacity, to see the asteroid coming and to move out of the way. Ideally, you want a librarian which carries the library with it. This could be anything from a person-like creature (though biologically immortal) actively seeking unobtrusive places to wait out the ages, to a spaceship passively observing from a "safe" orbit, until that orbit doesn't seem safe enough, then moving to the next location - except for when it has to venture out to resupply, and then continue to wait. Whatever this thing is, it must be programmed to be intensely risk-averse, keeping out of the way and making sure it doesn't end up in a situation that might lead to a failure of its mission. To be triple-sure the data is preserved, have more than one librarian, each independently storing the data and avoiding the other librarians. The main difficulty (besides designing an agent to last out the required length of time intact), is finding your librarian when the time has finally come (and convincing it to come out of hiding). --- Bonus thought: Perhaps your librarian, after hundreds of millions of years, seeing itself failing, but totally dedicated to the mission of preservation, may in the final resort try to recruit someone else take up its task of protecting its store of data. [Answer] Energy and data are two different things. To preserve data by encoding in human (or any type of animal) DNA would not be reliable, because it assumes that humans would still be around in 300 million years. You could etch the data in thin gold plates. A real world example of this would be Voyager's Golden Record. However, there is still the issue of whether humans having knowledge of the ancient language would still be around to read it. The language and scientific knowledge would have to be preserved for the data itself to be relevant. But if the language is preserved, wouldn't the data be passed down too? [Answer] Encoding the information is no problem; carve a message into some stable material (I would recommend glass or gold) and store it somewhere safe. It is that second part that is the problem though. No matter what material you pick, erosion is going to wear it down. The safest place to put it would be somewhere on the Moon. Just be careful and make sure you don't pick somewhere near an asteroid impact. Also, cover it with a thick sheet of lead to protect against radiation. Assuming that is not available, I would think about going really deep into some cave systems, especially if you need to dive to get there. The problem is that even though these systems can easily preserve things for billions years, it is hard to identify in advance which ones will still be around. In addition, if an earthquake or flash flood changes the structure of the caves, then any plans made before the timetravel on how to navigate the caves becomes useless. My last option would be burying it in a bog or somewhere are you know sediment is going to collect. Hopefully, it will become part of a tar pit or sedimentary rock. Since this process itself takes millions of years, there is no guarantee that it will take place. [Answer] From other suggestions in comments to other answers, maybe we should not think miniaturized data storage, but go big. Really, REALLY big. So big you can read it from a very long distance. Make the entire surface of the Moon as the storage media. Use asteroids to engrave the surface. Those asteroid craters on the Moon are not random, they are a pattern intentionally laid down by some civilization, using well-aimed asteroids and kinetic impactors. A very large QR code, readable even as far away as from Earth. The entire SURFACE of the Moon as a gigantic billboard. Hidden, all that time, right in front of our eyes. Now all we have to do is develop the correct QR code reader. We just have to filter out the background noise from the random impacts, but huge craters are very resilient to erosion and decay. There will be some sign of them for far longer than 300 million years. [Answer] My answer is more about where to put it than how to store it. I agree with several existing answers that properly stored physically encoded inert materials could work, but how do you find them 300 million years later. For the answer we should ask what identifiable material do we have from 300 million years ago. The answer, fossils, lots of fossils. 1. Step one - in the present map existing fossil excavations from the desired time period, these tend to occur in groupings of sedimentary rock, and bonus are often in remote locations. You know based on the fossil finds that these locations are going to be stable for the required time frame, you may want to pick ones that have only recently been starting excavation to prevent disturbances in the recent past. 2. Pick one, use some simulations to predict where in the past these sites correspond to. Depending on the specifics of the time travel you may even be able to experimentally verify these predictions. Did it work, well yes we know it already worked, we found the message 6 months ago (time travel often leads to these kinds of weird causality issues) 3. In the past locate the site and bury your properly sealed and encoded time capsule in the mud at the sites. You may want to make them easier to find by marking them somehow, high density, ferrous, or radioactive materials would make them more detectable, to narrow down exactly where to dig. You could also put in some fake or real fossil in if you want to mess with the staff paleontologists (Who carved their initials into the Edaphosaurus bones!) 4. Wait 300 million years for the mud to turn into sedimentary rock. 5. Fund a fossil dig in your chosen location. 6. Find message capsule. 7. ???? 8. Profit? [Answer] Write it on stone. Yeah, that's right. carve it on a giant stone sphere in geosynchronous orbit above earth. That's high enough that it's not going to degrade (if it isn't high enough, orbit it higher). A 9 mile diameter stone sphere ought to do it: area of a stone sphere A=4\pi()r^2 Solve for r r=(A/(4*pi()))^.5 A= the area of all the data: 1byte=1 letter= 1 Inch^2 so A=area of 1 terabyte of data A=1000000000000 inch^2 249.098 Miles^2 then r= 4.452 Mile diameter stone. Make it happen. ]
[Question] [ In my setting, wizards from a pre-industrial fantasy world come to real life. One of these wizards is a destruction mage recruited by the US military and tries out her talents against modern forces. Her favorite spell is lightning bolt. She simply shoots out lightning at whatever target she wants. Once released, the lightning acts like regular lightning only directed at a target. This destructive witch unleashes lightning bolts at various vehicles in the current US military. She throws lightning at tanks, fighter jets, helicopters, APCs, humvees, drones, warships, and even submarines. Would lightning be effective against any of these targets? By effective, I mean that either the vehicle is disabled, the vehicle is destroyed, or the crew inside the vehicle are severely wounded or even killed. [Answer] Not effective at all. Now - let's be charitable, some of the electronics inside modern military equipment don't like being struck by lightning and so you may get some reduced functionality if she gets a particularly lucky hit. The problem is that the vehicle will just conduct the lightning into the ground, acting like a Faraday cage for its occupants. For aircraft this is a common occurrence, with commercial airliners getting struck on average once or twice a year (doesn't sound like much, but point is, if it did any serious damage, we'd notice). There's even a good question on the Aviation SE: [Here](https://aviation.stackexchange.com/questions/888/what-happens-when-an-airplane-gets-struck-by-lightning) Ah - but I see you say - they are magical! And can cast many lightning strikes! Still ain't gonna do squat. Here's Richard Hammond from classic Top Gear, sitting in a car being subjected to multiple lightning strikes: [Here](https://youtu.be/GZxgYNnkBd0?t=217) You'll note that despite being scared, he's otherwise unharmed and the vehicle is fine and completely operational. [Answer] ## Your mage is not much more dangerous than your average infantryman Fighter jets, helicopters, warships, and submarines are all speced to take the occasional lightning strike and be fine. These are common enough hazards that being able to take it is part of the design. Most drones will probably be fine too since that they are not grounded; so, not a whole lot of potential for destructive currents to be drawn through it. Tanks, APCs, and humvees are the only vehicles that have anything to worry about. There have been reports of lightning hitting tanks and other ground vehicles. Normally it will fry a bunch of electronics, but wont harm the people inside or completely destroy or disable the vehicle. So while a bolt of lighting will do more damage than a standard infantry riffle, there are plenty of man portable tank killer weapons out there that that are arguably more effective than lighting. Good thing about lightning is that is can spread out and hit several infantry at once... but so can Machineguns and RPG, so still not really proving any more dangerous than many infantry weapon systems. All this said, there is one factor that REALLY limits mages in modern warfare and that is human perception. The modern battlefield is full of all sorts of kill-you-over-the-horizon weapon systems that a fantasy mage would have no counter against. Even if her magic were powerful enough to be a real threat, all of her fancy light shows would attract a lot of attention and she may just find herself exploding into a mist when she finds herself on the receiving end of a smart shell fired from 10km away. ## Ways to make her much more dangerous ### Strong control over directionality > > Once released, the lightning acts like regular lightning only directed at a target. > > > All this said, HOW directed at your target could matter a lot. Several countries have experimented with electro lasers for shooting down planes and missiles using far less power than an actual lightning bolt. Lighting by its very nature spreads out a lot and wastes a lot of its energy, most lightning bolts never even reach the ground in any apparent way, but if all the power of a lightning bolt were actually directed into a single point, it would be incredibly destructive. A typical bolt of lightning is about 1,210,000 kilowatts, but electro-lasers in the 30-120 kilowatt range are sufficient for blasting a small hole in an light armored vehicle; so, if your mage were to actually direct the full power of a lighting bolt into a target, it could easily take out a main battle tank or cause significant damage to a warship. ### Magical answers to modern information driven warfare systems A mage that relies on thier own senses can't attack or defend against modern information driven warfare systems no matter how hard she hits. If the mage starts to cause to much trouble, she will quickly find herself on the receiving end of a super-sonic artillery shell or missile fired from 10s or even 100s of kilometers away. If modern tech can attack her from outside of her nexus of awareness, then no amount of magic will save her. That said, a mage may have tactically useful powers other than lightning bolts that are comparable to or otherwise counteract modern information warfare systems. Some examples include: * Recon Powers: If she can command familiars, astral project, and/or scry, then she can gather situational awareness over a whole battlefield in ways that are comparable to modern methods. So while she may still be vulnerable, she at least has the ability to try to hit first. * Cloaking Powers: If she can bend light to make herself invisible or hide herself in darkness or hide her body heat in mist or something like that, then she may not be able to see over-the-horizon threats, but she might at least be able to minimize the threat that they can pose to her. * Defensive Powers: If she has some kind of protective charms that passively protect her, or perhaps has some kind of precognition or danger sense so that she knows exactly when, where, and how to defend against attacks from distant weapon systems, then she could use magic to stop attacks that she would otherwise not even be aware of. ### Make her an assassin, not a solider The ability to summon lightning is a great assassination talent since she does not need to carry any weapons to be able to kill a person of interest. She could get on a plane, walk right into some enemy dictator's political rally, and cut the head right off the snake after walking right through numerous checkpoints. ### Allow her to attack from the sky The power's usefulness could also be improved if she could summon lightning from the sky, instead of shooting it from some part of her own body, because that would make her attacks virtually untraceable. Modern warfare significantly favors the combatant that can stay unnoticed until the shooting starts, but being able to stay unnoticed AFTER the shooting starts is the holy grail of modern combat systems. In this case, she could kill political leaders or attack enemy positions from a near-by vantage point, and no one would know where to even aim to defend themselves. Coupled with strong control over directionality, she could wipe out entire military convoys or sink fleets and modern militaries would have a very hard time knowing what to do about it. [Answer] Most of the answers above are focused on the fantasy side of things. As a former military guy I can say this is something that we do test for. When the US military issues contracts for new equipment and wants to define specifications this is often done through the Military Specifications (MILSPEC). For any given piece of equipment, a contract will typically specify what aspects of the MILSPEC must be met. Ex: I worked on servers a lot so vibration was a common one. You want to know if the server drops off the Humvee that it doesn't just explode. Here are the specs I found related to lightning: * [MIL-HDBK-419A - Grounding, Bonding, And Shielding For Electronic Equipments And Facilities Volume 1 Of 2](https://wbdg.org/FFC/NAVFAC/DMMHNAV/hdbk419a_vol1.pdf) * [MIL-STD-188-124B - MILITARY STANDARD: GROUNDING, BONDING AND SHIELDING FOR COMMON LONG HAUL/TACTICAL COMMUNICATION SYSTEMS INCLUDING GROUND BASED COMMU](http://everyspec.com/MIL-STD/MIL-STD-0100-0299/download.php?spec=MIL_STD_188_124B.1706.pdf) * [MIL-STD-1757A - MILITARY STANDARD: LIGHTNING QUALIFICATION TEST TECHNIQUES FOR AEROSPACE VEHICLES AND HARDWARE](http://everyspec.com/MIL-STD/MIL-STD-1700-1799/download.php?spec=MIL-STD-1757A.026708.pdf) * [MIL-STD-1541B - MILITARY STANDARD: ELECTROMAGNETIC COMPATIBILITY REQUIREMENTS FOR SPACE SYSTEMS](http://everyspec.com/MIL-STD/MIL-STD-1500-1599/download.php?spec=MIL_STD_1541A.1500.pdf) * [MIL-STD-464 - MILITARY STANDARD: ELECTROMAGNETIC ENVIRONMENTAL EFFECTS, REQUIREMENTS FOR SYSTEMS](http://everyspec.com/MIL-STD/MIL-STD-0300-0499/MIL-STD-464_21937/) Short answer - as other people have said, probably not. Lightning is pretty common and the military plans for that stuff (as evidenced by the existence of the above standards). Also consider that anything meant to be part of nuclear delivery has to have its electronics hardened against electromagnetic interference ([nukes have big EMI](https://en.wikipedia.org/wiki/Nuclear_electromagnetic_pulse)) so it's not just lightning the above is meant for. Edit: For anyone wondering, no, when they say in movies that something is generically "Military grade", that's complete nonsense. There's what feels like a billion of those MILSPECs so you would have to specify which one you mean for it to make any sort of sense. [Answer] One point that other posters have missed is that lightning is blinding (and to a lesser degree, its thunder deafening). Military personnel and equipment will be protected against this to some degree, but a bolt of lightning is beefier than your average flashbang. There will likely be a period of time before defenses adapt to the new threat. The wizard might not disable vehicles, but they might blind them. [Answer] Depending on how much precise is the lighting bolt application, one can disable and/or destroy almost whatever of modern technology. Natural lightnings are generally safe for modern buildings and vehicles because we are quite good at directing the electrical discharge to safe paths. On the other hand, a directed hit somewhere inside a vehicle or below the lightning rod of a building can have a spectacular effect. Hit the dashboard of any vehicle and the engine stops for good. Hit a stockpile of munitions and they go off. Hit a local power line - minus computers and machines in the building, a fire is optional. High-power, high-voltage power lines are better protected, but a temporary wide-area blackout should be doable. Hit a gas station pump (the rubber fuel line is the best target) ... [Answer] I upvoted @TheDemonLord's answer, you should too But let's build on it. [Lots of people have survived direct lightning strikes](https://www.weather.gov/safety/lightning-survivor). Often with substantial long-term effects, but they survived and they didn't have the benefit of being encased in an Abrams M1 Tank. Then there's the issue of modern vehicles which are specifically designed to protect both the passengers and core electronics, so it's no wonder that the car in Demon's video started... and the most serious damage might be that the battery has about a week of life left in it. Vehicles use a "chassis ground," meaning the negative battery post is connected to the frame, which means some of the lightning is being shunted to the battery. But only some. (BTW, military vehicles are designed to protect the battery when they run over charged things... like downed power lines....) Anyway, lightning looks and is impressive ([1.21 gigawatts!](https://youtu.be/4BVQri3aLfg?t=15)). The U.S. National Weather Service claims the average lightning bolt is [300 million volts and 30,000 amps](https://www.weather.gov/safety/lightning-power) or 9,000 gigawatts (take that Doc Brown!). But we need to take that with a grain of salt because all those volts and amps (remember, V\I=Watts or Joules/second) happen in a series of strokes, each of which only lasts about [60 microseconds](https://www.public.asu.edu/%7Egbadams/lightning/lightning.html). So, 9,000 gigawatts \ 60 microseconds = 540 megajoules. (Some online sources claim the average is 1,000 megajoules. They're probably considering lightning in the aggregate.) Which is still a lot of energy, don't get me wrong. So why did the passenger in Demon's video survive? My college physics professor ran a cool experiment, *(DO NOT DO THIS!! He knew what he was doing...)* he had a high voltage gap-arc generator, stood a distance from it, and lifted up a fluorescent bulb in each hand. The energy passing through the air (air gap discharge) illuminated both bulbs. The electricity didn't just jump the air gap, at that high a voltage it runs along the surface of your skin rather than passing inside through your heart, which kills you. Most of the energy, even with vehicles having vulcanized rubber tires, is jumping the air gap to ground rather than damaging passengers or vital electronics. The voltage is just too high, the energy is being ferociously pushed along the easiest path (rather than the shortest path), which is the surface of things and a quick jump to Earth. Remember, lots of people have survived direct hits. And that because the electricity doesn't flow through the body, it flows over the body. Conclusion: lightning might burn the paint RPGs like Dungeons and Dragons aren't interested in physics. There's a weapon that happens to be called "lightning bolt" that causes a prescribed amount of damage against opponents. You're in exactly the same boat. Physics shouldn't mean squat to you. If you want your magic system to fry an Abrams M1 Tank via a spell called "Lightning Bolt," you do that. And don't lose a second of sleep over the fact that science says it can't be done. [Answer] The basic aspect of lightning is that there is an electrical potential developed between two points and that potential is suddenly shorted. Most thoughts of being able to cast lightning is using a lot of space to generate that electrical potential and resulting high voltage and amperage that is very flashy. The prior answers cover why that doesn't work very well. If, on the other hand, the caster could generate that electrical potential within a small space such as within an electronic device, now we are talking about a skill that could take out all the electronics in any vehicle. Several hundred volts with some amperage within the electronic device will fry the electronics. (I fried a PDP computer with just 110 volts on a current loop interface. It took only a small spark.) Such a skill would not be flashy. There wouldn't be any big show. Simply wave a hand, lots of little internal sparks and all the electronics in the neighborhood die. Electronics controlling the engine die. The targeting computer dies. The GPS receiver dies. The flight control electronics dies. Military communications equipment dies. Modern warfare is heavily dependent on electronics and the caster can mess that up. [Answer] Other answers already described that Lightning Bolts are not effective along with the reasons. I also agree with all of the answers here. However, if your magic users can conjure/control lightning bolts at will then I think they might consider changing the way they use their talent. I suggest they try to learn a higher skill that is an advanced branch of how to use lightnings. --- ## [Railgun](https://en.wikipedia.org/wiki/Railgun) The wizards can improvise their technique to control lightning in such a way that it replicates how a railgun works without creating or having such weapon. It is destructive depending on many factors but the obvious ones are the attribute of the object that is shot and how much energy it uses. This way the lightning users now have a chance to dominate the battlefield. ]
[Question] [ Humans build big rockets and fly generation ships to extrasolar planets to settle. There’s already sentient alien life on that planet, but the humans has none of the immunizations and natural resistance to diseases that the aliens do. How am I going to prevent the humans from dying en masse and going extinct from diseases like the alien flu or small-reptile-who-can’t-fly-and-lays-eggs-pox? Don’t worry about the aliens getting sick. After commandeering flight 19 and a few other groups of missing humans, they commenced immunization of their species against human diseases. Edit: not similar to the linked question because the other question asks for bacteria, and I am asking for viruses. [Answer] I am going to frame challenge this question. Why is this a problem? Are the aliens sexually compatible with humans? Can we see human/alien hybrids? Or perhaps their alien-cows can breed with human cows. No? Life is hard, it requires very specific conditions for it to function and flourish. Give a virus/bacteria too much heat, or to little it will die2. Mixup the PH of the substrate: too low or too high, it will die. Take a fish virus, and stick it into a human? The virus dies, the human doesn't notice it, human cells don't have the mechanisms that virus exploits to duplicate itself. Fish bacterial infection? Humans run too hot, it dies. # Then handwave the problem away with incompatible biology1. If a cross over event did happen, it would probably be extremely lethal and kill a lot of humans, possible all of them. And human scientists without any past experience with the new diseases wouldn't have enough knowledge about the disease to make a cure/vaccination. Aliens wouldn't have any knowledge either, being unfamiliar with human biology... ## So don't have it be a problem The chance of a virus that infects a species completely unrelated to us is very low. Their cells just wouldn't have the right mechanisms for a virus to hijack, and alien bacteria wouldn't be adapted to their biochemistry. Just think how rare of an occurrence it is for a virus/bacteria to jump hosts with creatures that are pretty close to us (Cows, Rats, Dogs, Cats...) [1] There might be a crossover event in the future as "Life, Uh, Finds a Way." There is a chance however slim that a virus/bacteria mutates something that allows it to survive in both Alien organism of some sort and Humans, but that is a problem for future humanity, not current humanity. It also might never happen, if humans/aliens are different enough biologically. I don't know of any instance where diseases jump from Alligators to Humans, and we come from the same common ancestor. [2] Extremophile bacteria exist that can survive in both really hot/really cold places, However those extremophiles do not survive in places where other bacteria live, they only seem to survive/thrive in environments hostile to everything else. [Answer] Some introductory biology could be helpful for you if you want this to be believable. For example, your edit details don't make any sense in terms of biological function: > > Assume in all applicable cases that the pathology for the aliens would be mirrored of our diseases. (E.g. if the flu DNA is ACCGTTG, the alien flu is TGGCAAC) > > > That's not how functional biological information works. Living things store information in DNA/RNA, and use that information to make proteins, regulate their states, and replicate that information, among other things. The central dogma of biology, describes how information is transcribed from DNA to RNA, and then translated from RNA to proteins. Proteins are the workhorses of biological systems--they're quite literally little machines that catalyze reactions, move things around, error-correct, and more. So a few things: 1. If you just flip the bases, assuming the alien codon system was the same, chances are exceedingly high that you just get some useless information that doesn't make anything functional. 2. You could get around this by assuming that the aliens used the same nucleotides, but have a different codon chart (groups of those nucleotides correspond to different amino acids, and therefore different proteins). BUT if they entered our cells, with our cellular machinery, they would again be useless because their information wouldn't correspond to how we translate information. (an analogy would be going to Spain and speaking english--in England what you're saying means something, but in Spain no one can do anything with your information because it's decoded differently. Bacteria would be a different story, because they don't have to hijack our information processing systems. [Answer] Soften them up first. Before the humans come 1: Rockets with neutron bombs. Get rid of as much of that pesky alien life as you can. Then right behind the bombs- 2: Rockets full of poop and dirt. A bunch of good home planet micro-organisms. WHatever aliens are left will still be reeling from the bombs. Earth bacteria, fungi and micro-organisms can make the alien planet good and earthy. 3. Now land the humans! They will feel right at home. [Answer] # Send an advanced party. If you're gonna start a colony you're gonna want to do a few tests first. Send down a few UAVs to survey the area and grab samples, and then send down a few scientist colonists with some equipment to test the common local wildlife for diseases. They can stick their blood in a petri dish with human cells and see if anything reproduces well. If they find anything bad they can fast track a vaccine. # Quarantine the people At the early stages you're gonna want to be very careful with your people. Anyone who goes out and interacts a lot with alien wildlife will need to be quarantined for a while and have some medical tests done. # Fast track antibody treatments If you can cross the stars, your biotech is probably advanced enough to cheaply make antibodies. If someone gets infected and produces an antibody which can damage the alien pathogen you can mass produce that antibody and give it to everyone. [Answer] 2 options: Burn the entire planet then settle, or cooperate. Humans need to exist in sealed and controlled communities until they develop immunity to the new world diseases. First you must establish good relations with the locals. A cynical man might point out to the colonization of the Americas. But this is the opposite. They are the ones with the ability to kill humans with nothing more than common diseases. With a sentient life form on the planet. them weaponizing diseases is a recipe for disaster. They don't need to invent nukes. They just need to cough in our general direction. And if they are capable of engineering viruses or such things. This it's better to either destroy them or coexist. So. Either completely burn all life on the planet, burning everything including bacteria and viruses. Or just go in and get them to give you a big piece of land that nobody is using and would make a good colony. Exchanging knowledge and resources would be a great way to benefit everyone. [Answer] # Don't Land: Until the people identified the threats on the planet, there's simply no way they would go to the surface of the planet. They wouldn't even allow direct contact with the aliens. Humans are already working out the protocols for this, and have dealt with lots of diseases. There are plenty of cases on Earth of local populations (or sometimes crews of ships) being wiped out by a surprise disease. The aliens already possess an advanced industrial base and technology if they have traveled to Earth and back before humans even could, and have advanced biotechnology. If they don't want us there, odds are we don't stand a chance. Landing would be exceedingly foolish even if there weren't diseases. Once the colonists learned the aliens were familiar with humans, the colonists should really crank down and be on their best behavior. Ask nicely to get an out-of-the-way corner to build habitats. Make friends with the aliens to learn their capabilities. Copy any available technologies and broadcast the information back to Earth. Ideally, the aliens will overlook the human history they may have seen and be friendly. If so, the biology sounds close enough that if the humans themselves can't develop medications and vaccines, the aliens may help them. After all, they've already studied our biology. * Biology is messy, and while the aliens may have studied diseases that affect humans, there are a lot of other diseases and invasive species that could spread back and forth. Wiping out the green pig-oid farm population of animals might be almost as devastating to the aliens as if they got anthrax. Similarly, terrestrial animals and plants could suffer from molds and growths that will destroy food supplies, melt plastics or rapidly oxidize metals. [Answer] There are couple facets to the biological hazards that you need to consider. 1. Viruses. This one is actually the least threatening of them all. Notice how rare it is for a virus to jump between earth species. A flu virus that can be transferred from pigs to humans? That was a huge deal! But from humans to entirely different species? Unless they use the same kind of DNA and are actually our crypto-ancestors (or humans are theirs), it is not happening. The inner workings are just too different. 2. Bacteria. These ones are an obvious contenders. They don't need to be compatible with host organism, they just need acceptable environment. If they find that human blood is edible, and find a way in, then you have a real problem (TM). Or any part of human body really - if they can live and thrive in there, and produce harmful byproducts, or use up some valuable resource, you have an alien disease. On the plus side, bacterium are usually large, complicated things. If your humans have an access to good electron microscope imaging and can synthesize molecules and proteins in lab, they should be able to quickly manufacture substances that damage the bacteria outer shell, or their inner workings. That's what some antibiotics do - they just "disassemble" the outer shell and whole bacteria rips open. Given the alien disease will be strikingly different to human cells, it might be possible to use "strong" substances that affect the intruders, but are otherwise neutral to human biology. A bacterium susceptible to ethanol? Colonists are going to love the treatment (and hate the hangover). But we're not done yet. Enter 3. The fungi. Shrooms and all that weird stuff. They vary in size from single cell to complicated multicellular organisms. If the local fungi can process anything found on human body, you will have a problem. A spores that like wet conditions, total dark, and feed from airborne particles? They are going to love human lungs. [The gross description of having something growing in person lungs is left to the writer]. Or maybe they like to go after human shed skin? Or toenails? There is a lot of inspiration in nature. There are also fungi that love some organic or inorganic compounds. Imagine one that loves eating polyester. Human clothes just falling apart [totally not a setup for adult movie or comic]. Fungi are often tough bastards, but we managed to find substances to fight them, so the human colonists should be able to do the same. Air filtration, containment control, frequent checkups. 4. Parasites. You could also consider some small animals that can feed on something human produces, or just want a "safe" nesting spot. Standard safeties apply - a macro scale problems like this can be treated by direct intervention. Anyone say "space ticks"? And finally, consider basic non-biology hazards: * does the air contain enough oxygen to be viable? * any other gasses or airborne compounds that are harmful? * is that pool water or sulphuric acid? [Answer] Just plop down and deal with it We are talking about a spacefaring civilization that is colonizing foreign worlds. Aka they have likely already colonized some dead worlds and have an interplanetary civilization. Distant, separated human communities (be it full planets or "small" 2000 people outposts) are already a perfect condition for something far worse than alien diseases\* : Evolved, novel diseases adapted to infecting humans. If you let the common Flu evolve in a separate group from most of earth and after just 10 years introduce that specimen to earth, we would likely have something far worse than the current Covid pandemic. Since your civilization still exists however (and even flourishes, given they want to expand), they must have mastered time-critical vaccination campaigns long ago. Something that is not that unrealistic either: We, with our 2020 tech managed to develop a decent enough vaccine in under 2 years. And we struggle hard to just get to the moon. So even if your human's medical science evolve at just a fraction of their spacefaring skills, developing a disease (and likely even in-vitro antibodies for those already infected) within a day seems very plausible, if not just logical. Also: yes, some diseases could be too foreign for these methods to work. But then they would also be too foreign to abuse human biology (like viruses or most problematic bacteria). If the bacteria (because it won't be an alien virus) is only after "digesting" us like mould then we could have a problematic case, but one where the disease would progress slowly enough for a cure to be found anyway. [If that diseasy is problematic by producing toxins, then those would be picked up as present in pre-colonization planetary scans already and airlock- or sterilization-based colonization would have been chosen anyway] \*which, as shown in the other answers are very likely simply irrelevant to human biology ]
[Question] [ In many fictional franchises we see people like the Flash who can move at speeds defying physics. In my story I want to include a speedster, however I feel that they would be too overpowered for the setting. So my question is how do non-speedster characters defeat those with speeds equivalent to those of say the Flash? Because in many settings these characters are shown to be nigh invincible because no one other than speedsters can stop speedsters. [Answer] Every good hero has a fatal flaw. Even Superman has kryptonite, and is arguably kindof a coward. For your speedster, maybe he's not very good at forward-thinking. The non-speedster only has to set up some bait and swing his bat -- the speedster hits the bat every time, and at those speeds, the blow does a lot of damage. For that matter, your speedster can't afford to take a hit while he's moving fast at all. Even if a bug gets in his way, it'll be like a paintball or a bullet, depending on his speed. The non-speedster just has to throw some sand in the air, and it'll disintegrate the speedster as he moves through it. [Answer] We can add some real science back into this to help handwave some things. Science and handwaving, what fun! This speedster is fast, real fast, but where do they get the calories to burn for this speed? The faster they go, the more calories they need. Let's make a ballpark figure and say at full near light speed, they are burning 1000 calories a second. At this rate, an opponent merely needs to wait for the speedster to starve themselves and fall asleep or die. This means the speedster can only operate in short prepared bursts and must stop frequently for food and water. They can't just run around the world, they would burn up all their muscles before they got half way over the ocean. And there you go, a plausible limitation that lends itself nicely into multiple possible story puzzles for heroes and villains to solve. [Answer] Even assuming the Flash got all the powers he needed, super stamina, near indestructable body, etc, A real-life Flash running at hundreds of miles an hour would actually have several weaknesses just from the laws of physics. IRL, there are a few major problems with running super fast. Many of these problems would severely limit a speedster superhero. Both Friction and Inertia would be his enemies. Pants on Fire - In reality, I doubt any material is both flexible enough to withstand moving at hundreds of miles an hour, and frictionless enough not to burst into flames. The Flash will have to slow down if he wants to keep his clothes on. Cool-Aid Man Stops - Remember how the Cool-Aid Man breaks through the wall to hand out cool refreshing sugar-water. Unlike in the comics, where the flash can run up buildings, inertia means he'd likely run through the wall, shattering it or himself into pieces. Skid Marks - Running straight is easy, but every time he turned, he'd leave deep indentions in the grass, broken pavement, and the like. It would be pretty easy to follow him to his secret crime lab. Turning on a Dime - Similar to above. The Flash would not be able to turn quickly given his inertia and small mass. Simply block stright-aways and the Flash has to go MUCH slower. Throw in some trip wires and obscured holes and you'll probably be able to nab yourself a speedster. Follow the Fire (and Noise) - Running super fast will create friction (i.e. heat) with the air, even if the suit is frictionless (see #1). He'd also likely sound like a sports car zooming past. A heat-guided missile + some other smarts would probably have no problem locking onto him. Calorie Deficit - [Marathon runners burn about 2,500.](https://www.theactivetimes.com/how-many-calories-does-running-marathon-burn) . That's a few minutes of running for the Flash. Simply pay off pizza and burger joints to find out who the skinny guy is that eats 5 burgers a day, and you'll unmask your hero. How do you say Adamantane - The Flash will need a special suit + special communications devices that work at his speed. Those will be one of a kind. Simply follow orders of exotic materials until you find the crime lab. [Answer] Don't use the Flash. You are right speedsters like Flash are too OP. But it is cool to have people who are really quick. It might be even cooler to have them be just past the edge of what is humanly possible. My suggestions 1: Think of things you want your Speedster to do. For example, a person who could process fast and move fast might be just about impossible for a normal person to catch / hit. I know because I lived with a guy like that. After he ate your food he would head off across campus, giggling, staying just 10 feet in front of you, and sometimes even lying on the ground. But he could always scramble up and get away before you caught him. You would need a team to do it and by the time you assembled them he would be gone. 2: Rule out impossible QuickSilver type stuff. 3: Figure out weaknesses. For example someone who thinks and acts really fast might not take the most prudent course of action. Like failing to have a line of escape set up when he set about eating all the BooBerry cereal. 4: Defeat the speedster. Normal speed person can defeat the speedster by exploiting those weaknesses with a trap or the like, or an endurance contest. Or failing that having a team to surround him. Or coopt the Speedster to your side (BooBerry might work). [Answer] Tie their shoe laces together? In all seriousness, your best bet is to use their speed against them. It doesn’t matter how fast they’re running, if they fall over they won’t be running for much longer. By far the simplest way of stopping them is to dig a 1ft by 1ft by 1ft hole, essentially a rabbit hole. If you’ve ever stepped in one, you’d know how easy it would be to twist or break your ankle. Now, imagine you’re running at these high speeds, not a care in the world, and step into one of these holes. At best, you’ve twisted your ankle and torn the tissues in your leg, you might instead break your ankle, your leg, damage the nerves, tendons, muscles, perhaps even the artery in your leg. A potentially fatal but easy to construct trap. Going slightly bigger and more advanced, you could have the good ol’ pit fall trap, a large pit covered by a tarp and hidden using sticks and dirt. The speedster runs over that, they’re going too fast to stop and falls in the hole. The fall may not be lethal, they may just break their legs in a cruel twist of fate, but you can easily make it lethal by putting wooden spikes at the bottom. Further options are trip wires, caltrops, raising low-barriers or wet/slippery surfaces. All of these would cause major issues for a speedster. I also remember a story, i don't know its true though, where during the second world war, piano wire was tied to trees or lampposts so that the wire stretched across roads. This wire was tied so that, if you were sitting down, it would be at neck height. The idea of it was to kill Nazi motorcyclists by decapitating them as they drove past, using the speed of their bikes against them. Because of how thin piano wire is, you wouldn't be able to see it and, by the time you did, it would be too late to stop. As i say, i dont know if this was true, its just something i’ve heard. Taking inspiration from that idea though, you could have walls of clear glass, like French sliding doors. If a speedster ran through it at high speeds, they might be cut to ribbons by the shards of glass and have glass in their eyes. If you were talking about in combat though, i suggest pike formations. Speedsters, like horses, aren't stupid enough to run into this big, sharp pointy stick. However, if you had these hidden in long grass, for example, and lifted them up when they got close, they may not be able to turn back in time and be skewered. [Answer] Most answers have focused on weaknesses of high speed, I'll try some things against high powered speedsters. Your typical superman, quicksilver and flash often spend more time in normal speeds than superspeeds. Bring a high-velocity weapon like a powerful laser to the battle and fire when they are moving normal speed. If you intend to do an Evil speech first, disguise the laser in your suit or clothes so by the time the speedster sees what is about to happen he's already being burned and possibly blind. An easy target. NBC's, Nuclear, Biological. chemical. You are fighting super-powered beings, take your time killing them! If you can get your hands on them you could set up a scenario where the speedster will cross a radiation area with enough radiation to kill in months... Or if you have more it might kill in weeks, days or even minutes even if the speedster exits the field. Unless the speedster has a geiger teller with him he (or she) wont even know he was radiated and dying. Biological is another one. A powerful disease could sicken the target without the speedster knowing. The disease could be lethal, or cause deleriums that are harmless to normal people but to a speedster could cause problems if he uses his powers. Or just weaken him for you to finish. Chemical is probably where it's at. A speedster's body might be able to speed up its immune response against virusses and bacteria, but if his body speeds up carbon-monoxide poisoning you are farther from home and something like that often happens unnoticed, especially in a scenario where the speedster is busy with other things and their fellows are as of yet unaffected. Lethal, odourless chemicals are easier to get your hands on than nuclear and biological weapons and can potentially kill in a moment especially if the chemical's uptake is accelerated. [Answer] ## Make the speedster unable to interact with the physical world while travelling at ludicrous speeds. While they can travel at speeds well above sound, or even possibly light, they can only do so by not being entirely in our physical universe. When the speedster phases out of the universe, they are actually running in a parallel dimension that lacks friction, relativistic constraints, etc. However, in order to interact with our phase/dimension, he/she has to re-enter and become subject to all of the laws of physics. This can allow you as the writer some flexibility, as the speedster could time the rentry and speed changes so as to take advantage, but then it would either have to be pre-planned (ambush move) or would involve significant risk of going wrong. It would be much easier for the speedster to re-enter normal space time without interacting with anything, act, then speed off again than to attempt to do something during the transtion between the alternate state and the natural state. Hopefully that would be limiting enough, while still allowing the speedster to be the sort of menace you want. [Answer] Have the speedster depend on some rare substance that is expensive in order for their power to work. For example, speeding up may require quicksilver, which is another name for mercury. The speedster might be able to break a thermometer and drink the mercury inside without suffering any harm, but that will only last them five deconds of real time. If you really want to get serious, the main resource that may be consumed by speeding is lifetime. In George R. R. Martin's Wild Cards, there is a speedster who uses his powers for OP speed akin to the Flash's. After what seems like just a few minutes to him, though, he has biologically aged a handful of years. A little more usage of that power and he would drop dead of old age. [Answer] Area attack. In non-lethal version, that can be used even in crowded space, I find some irony of trying to run using super speed while having zero visibility because of smoke cover. For extra bonus tear gas can be used. In lethal version there is always artillery barrage or chemical weapons. For defensive purposes, his super speed would be of limited advantage, while dealing with electric fence. But the most evil trap could be... a glass door. I'm also curious, whether its possible to make a trap activated by Doppler radar. [Answer] You can also make it very human or real, for example they have the reflexes of a cat and speed of a Cheetah. So he caps out at 60-70 MPH / 90-110 KPH. But can only do that for short sprints, and the nemesis could be a satyr that can consistently run at 30 MPH or 45 KPH for much longer periods of time. Those should be humanly achievable with slight genetic changes, but not world breaking like running back in time. A formidable person/chimera, with clear limitations and strengths and wall running. [Answer] I recomend looking at Wally West (Kid Flash/Flash III) rather than Barry Allen (Flash II) and Bart Allen (Kid Flash II/ Flash IV). Yes, there are four Flashes. Forget the golden age one but he's the old guy with the winged helmet. Anyway, all but Wally West were attached to something called "The Speed Force" which allowed a lot of physics defying that Wally West had to account for. Wally wasn't as fast as the other Flashes and had to count calories to an insane degree. He also could get injured from hitting something hard at speed. Another Speedster to look at is X-Men/Avenger's Quicksilver, who was pegged closer to speed of sound than Speed of FTL that the Flashes had. Quicksilver's speed was more related to localized time distortion (very implied... it took a power boost to figure it out) and thus, he's moving at an average speed to his own point of view while everyone is going slow. To everyone else, we're moving normal and he's moving fast. This has some other weaknesses such as an inability to run across water, because he's technically not running fast enough to not break the surface tension. He's also gonna hit with the force of an enhanced human (but he can hit you many times over before you can swing back). Running into a wall or obstacle still hurts as if he had done it normally. And of course, he can't run the vertical length of a building without gravity getting the final word on him. This is also the in comics ability of the Space Stone, (as opposed to portal generation in the films), and the first person depicted weilding it was a character called "The Runner". Here, speed is achieved by folding points in space closer to the wielder's forward motion and expanding it once the point is behind him. From an outsider's perspective, he is covering a distance of miles in the same time ordinary people can cover feet. From his own perspective, the distances is shorter... He is literally "Making the Kessel Run in 12 parsecs" fast because the Kessel Run is normally 24 parsecs or some much greater dsistance. Since speed (v) is distance over time (v = d/t) those that have the power to manipulate either space (Distance) or Time selectively can achieve high speeds but not have to factor in limitations. [Answer] Give them meaningful restrictions. Personality flaws can be that, but sometimes that comes off as bad or worse, unfun, writing. A character too stupid to abuse an obviously overpowered ability like superspeed can break immersion and put off the audience. Physical weaknesses are preferable because they're easy to visualize and harder to bend for the writer. Kryptonite-like substances are a simple, but somewhat overdone, solution. I would suggest trying to put a "spin" on every power, some in-built mechanical hard limitation. What if the speedster draws his power from making his own body lighter? He could move very fast, but his attacks would not do much damage. Or he can no longer see and hear once he passes a certain treshold of speed. Maybe he doesn't move much faster than a normal human at all, but can accelerate to his top speed instantly, which would still allow him to attack at blinding speeds without making him as overpowered as a general purpose speedster. [Answer] Kinetic-Energy reactive materials As show in the episode "Fallout", of Season 1 of The Flash, Wade Eiling threw kinetic-energy reactive needles at The Flash, immediately incapacitating him, and nullifying him, as he dropped to the ground, in great pain, unable to move. Needles, bullets, swords, suits (for hand to hand), anything made from kinetictanium (pff!) could defeat a speedster, as they would home in on them. Not to mention traps, if one is expecting a speedster. This is obviously not scientific, considering that I doubt such a material does exist in real life (please correct me if not), but superheroes also don't, so, you know. Wiki link, but it has all the pretinent information. <https://arrow.fandom.com/wiki/Kinetic_needles> [Answer] Momentum One of the issues with speedsters is that they appear to be impossibly fast, but also impossibly agile. Take the latter away. Now, they can attain fantastic speeds, but once they're going it takes a hell of a lot to change course. A judiciously placed and unexpected barrier could see the speedster paste themselves over a considerable distance. [Answer] Computer-controlled autonomous weapon systems. Link a weapon system to a computer system and sensor array which is able to detect speedsters and automatically fire the weapon. Can the speedsters outrun a hypersonic homing missile? If they can, can they outrun a hypersonic railgun? Even if they can, they certainly can't outrun a laser beam. [Answer] The trick to taking out a speedster is to present a threat that he can't understand until it's too late. In one of the Teen Titan comics Kid Flash is taken out by poisoning the room. The poison is mostly harmless to everyone else because they inhale it in small doses, while Kid Flash breaths in so much of it fighting them quickly that he falls unconscious. Contact poison or even something that has to enter the blood stream could work well. There are substances that will seep through skin, and even most gloves and are almost instantly fatal. No amount of speed will warn you not to touch the doorknob. You simply must set up a situation where you can manipulate a speedster to follow a certain predictable course of action, like opening a door to save someone from a burning building. And if all that fails, just shoot him when he is not looking. Bullets are supersonic, and should give no warning no matter how fast you are if you can't see them. ]
[Question] [ In a world that I am building, there are two countries that both are fairly primitive and only have medieval methods of transportation. They have a huge meeting every 100 years. Other than that, they don't visit each other often, except during huge international crises. They have a five thousand miles wild desert between each other, and one road that is rarely ever traversed. This gap has hardly any civilization except for one enormous city right in the middle of the road. Now that's my issue. This city is thousands of miles away from any other civilization. I want this city-state to be self-supported. But how would this city get there? How could it survive without anything except a few fruit trees, and a small freshwater lake? This city-state is also thriving. How could this city-state grow its resources to support thousands of people? Remember, these people do not have any advanced technology or magic. Can I have some answers to these questions? (Edit: The city does not go to the meeting, but the travellers going to the meeting rest in the city. In this world, everything takes a very long time, and the people live a very long time, so the time isn't a big problem. The people die a lot slower and can live with little food and water. The water is coming from an underground stream. This desert has a slightly above normal temperature but there is no rain. Most people do not go all the way to the other country, but they go to this city or rest on the way there. This way there is a steady amount of trade all the time. It is known as The Trade Capital of The World.) [Answer] You have mostly answered your own question within the question itself. In fact, you did so near the end, using some of the same ideas that I was thinking of as I read through it. ## First a nod to similar real situations There have been many settlements, cities even, located in deserts, even in ancient times. Check out [Palmyra](http://www.ancient-origins.net/ancient-places-asia/ancient-city-palmyra-pearl-desert-005626 "Palmyra: The Pearl of the Desert"), [Masada](https://en.wikipedia.org/wiki/Masada "Masada"), and even Egypt (an entire nation, not just a city). There are many other groups of people who have lived in the desert and established villages or cities around water sources. Some of them, even in old times, extracted their water from underground. We need to rid ourselves of the false notion that desert means nothing but sand everywhere and nowhere for water to collect. Even in the middle of a desert it is possible to dig wells. You can even keep the "desert is a bunch of sand" notion for most of the desert for visual effect but have other formations interrupt it, or have the sand be only so deep and water collecting underneath. Palmyra was more like the city in your setting, connecting the lands on the opposite sides. The linked article above talks about how the city was on a trade route between them and how it was a cultural blend. Masada is known more for its defensive capabilities, and indeed it was famously used for protection. Not the same as your situation, but it demonstrates the ability of people to live in the desert. Your people would have it much better than Masada in a lot of ways, not just the lack of war. Egypt is a great example for your consideration because it was made possible by the Nile river. The Nile river would periodically flood, watering an even larger area, but also people would redirect some of its waters where they needed. This is a great parallel to what you could do with your lake, especially if you included any rivers flowing into or out of it. ## Water They have a lake nearby, good. Make sure the lake is big enough to supply all the water needed and that the lake itself gets resupplied somehow, then water is covered. The answer to the lake water needs to be more than a simple "'Cuz rain" since it's in a desert. I thought of a river, but then you get the question "Why don't people live all along the river, or better yet come down the river by boat instead of walking the desert," so the water should come from underground or the river should not reach to waterways that extend by rivers or oceans to the rest of the world. If the underground water is merely an ancient, trapped reservoir then it will eventually be depleted. You can either use this to supply a crises at some point, or you can say the underground water is a flow of water such as an underground river. The people living in the city might not even know where the water comes from; they don't need to know that the underground water flow exists. If it is an above ground river, think of the Mississippi river. That starts off as a lot of very tiny streams of water at higher elevation which keep combining until they form a huge river. In your case, the Mississippi river would reach to the end of your desert, so you either need to decide that this is fine, that the waters come from outside the desert, or you need to scale it down. I would suggest that you have tiny tributaries just outside the desert feeding into it and merging farther into the desert. The smaller waterways could be unusable by boat, and you could have a stretch of large river that is anywhere from 100 to a thousand miles long in the middle of the desert that empties into the lake. With this option, most of your farming would take place along the river leading to the lake, and the trees could grow around the lake. ## Food and building supplies Both the food and building supplies come from growing plants. Even if the people do not need as much food or water as we do, as you claim, they still likely need more than "a few trees." Fortunately, you have a water source that you can use for farming. If fed by a water flow, either above or below ground, you can make the amount of water be anything you want, so you can make the lake it empties into support any amount of trees or farming that you desire. You could have 100 trees or even a thousand or more, heck, you could have a forest in the middle of the desert, a forest fed not by rain but by the water that comes in underground into your lake. The people probably irrigate and grow whatever crops they desire, and they probably tend to the trees to make sure they have enough for what they need. So your people have food, water, and they have shelter and whatever else they can make out of wood. Sounds like you're set as far as survival is concerned. ## Medieval setting tools For other things beyond survival, such as iron tools, they can trade for those. This will work even with the very irregular contact with the outside that you specify as iron tools can last a very, very long time. I still use some tools that belonged to my grandfather, and I don't know if he got them new or if they were passed down to him too. Iron tools can last hundreds of years if they are not left to rust. ## People In order to have a city, you also need people, obviously. That is an easier part; you can just say that the road came first, built by the nomads who crossed the desert, and the city sprang up later when the lake and the few original trees around it were discovered. Note that the city probably started as just a few people staying near the lake they found and starting to garden at its shores. As those few people developed the land by irrigating and planting more trees and vegetables and building some permanent buildings, then other nomads may have joined them. Usually breaking the habits of those around you (in this case, being nomadic) is done by few people, then later others join them if they prove successful. And now you have everything you need available to the middle of that desert for a medieval setting. [Answer] # A mountain! Put a big mountain close to your city. Or, better said a volcano, because an isolated mountain would be too strange. A volcano can be pretty isolated, think for instance of the Kilmanjaro. So you have the desert, and in the middle of it, the big mountain (maybe 4000m above the desert level). The city lies at the foot of the mountain. This might solve some of the problems your citizens are facing: * Location: It is now easier to locate the city from very far away. So the visitors that are coming only once per 100 years can find it. Because otherwise, tracks get erased pretty fast in the desert. * Purpose: You could use the mountain to explain why people settled there in the first place: it’s a symbolic/religious/interesting landmark. * Water: Even if it doesn’t rain in the desert, it might snow at higher altitude. The snow would then slowly melt and water would steadily irrigate the city and your lake. * Food: Is it too warm to cultivate in the desert? Just go up a bit until you find the perfect climate for each type of crop. Volcanic soil is [usually fertile](http://volcanology.geol.ucsb.edu/soil.htm). * Tools and industry: The lava contains a lot of iron, maybe they can mine the volcano. (I’m not sure of this, but with some writing magic, why not. For instance this [mine](https://en.wikipedia.org/wiki/Kiruna_Mine) is based on volcanic rocks.) * Economy: The volcanic rocks have a lot of [other stones and metals](http://volcano.oregonstate.edu/book/export/html/170) to trade. * Strategical: It’s a very good lookout, it might have a lot of [caves](https://en.wikipedia.org/wiki/Lava_cave) to hide or to fortify. The caves can also be used to keep products at a relatively lower temperature. * Energy: Geothermic energy might be used by a more advanced society to create large amount of energy. A more primitive society could simply benefit from hot springs for heating or bathing. * Bonus: Caves that interconnect and create a hidden underground network are likely a bonus point for your plot. An eruption is also a fun event to consider for your plot. [![enter image description here](https://i.stack.imgur.com/fxxBD.jpg)](https://i.stack.imgur.com/fxxBD.jpg) [Answer] # Cities Require Flow ...which they don't have in this situation. With extremely limited local resources, the food, water and fuel required to make this city run will have to come from somewhere. Trade is the usual answer but there is no trade in this scenario. If somehow this city were plopped down in the middle of those resources, the city would be dead or deserted in less than a year. There just isn't enough to go around. Unless there is something extremely valuable nearby such as minerals, gems, special spices (Dune's melange comes to mind), there's no reason for those people to stay. There's no money to be made from trade or by selling. Diplomatically, this city doesn't matter since it's approximately the width of the United States (NYC to LA is 2700 miles). Meetings that are supposed to happen every hundred years, won't. That's like me trying to keep an appointment for a certain day and time that my great grandfather made. Especially, when it will take at least a year for me to travel to where the other party might be...and neither of us get lost or starve in the process. Also, long distance navigation is difficult. Assuming a sand dessert, it's very easy to get lost. Sure, trade across the Sahara happened but there are also many stories of entire armies getting lost and dying. [Answer] You want it to be a big city, you want it to be self-supporting, and you don't want to give it anything more than a lake and a few fruit trees. All three of these things can't be true at the same time! Certainly not without turning to advanced technology or magic of some sort. If you want it to support itself with medieval-level technology, then give it some nice farmland nearby, not just a few fruit trees. If you don't want to do that, then it has to be getting a constant stream of food and other supplies from somewhere else. Perhaps it's on a busy trade route, but then it needs nearby neighbours to trade with -- we aren't talking about a few pilgrims on a once-in-a-lifetime journey here, but huge trade caravans rumbling into and out of the city on a regular basis. And it still needs its own water source. Where is the water in the lake coming from? [Answer] If the lake is the only source of water, then you need a lot of irrigation. But the lake is below the surrounding land, you need a pump and a lot of aqueducts. It's extremely difficult to pump enough water for agriculture without modern technology. For example, at one point the Crossness Pumping Station used 4 enormous Cornish beam engines, and was able to lift 240 tons of water per minute, to a height of up to 40 feet. [![Crossness pumping station](https://i.stack.imgur.com/88asb.jpg)](https://i.stack.imgur.com/88asb.jpg) I like the Crossness station because it was originally steam powered, letting it operate with less sophisticated technology. I like this page for crop water needs: <http://www.fao.org/docrep/s2022e/s2022e02.htm> From the page: > > "For example, the standard grass crop grown in a semi-arid climate with a > mean temperature of 20°C needs approximately 6.5 mm of water per day. The > same grass crop grown in a sub-humid climate with a mean temperature of 30°C > needs some 7.5 mm of water per day." > > > So let's say we're talking 7.5 mm of water per day over the farmland, as a rough number. The absolute maximum number of people we could feed per square km of farmland is 2350 according to this question: [People fed per square km of farmland](https://worldbuilding.stackexchange.com/questions/9582/how-many-people-can-you-feed-per-square-kilometer-of-farmland) In practice we'd probably get a lot less due to sub-optimal crops, climate and land conditions. In other sites, I've seen figures of two people supported per acre, or roughly 250 people per square km. At any rate, we get 7.5 mm of water per day covering a square kilometer, giving us a water usage of 0.0075 m \* 1,000 m \* 1,000 m of water, or 7,500 tons of water per day. If we're powering our aqueducts with a Crossness Pumping Station equivalent, it would take about half an hour to provide that water. So we'd get around 48 square kilometers irrigated over the course of a day. That would support 12,000 people at 250 people/km^2, or 112,800 people at 2,350 people/km^2. (Of course, the sweet potatoes needed for the 2,350 number would also need more water) So if you had something as good as the Crossness, that's roughly what you'd be looking at. Which brings us to our second problem: it's a desert, so there's no wood or fuel for our pump, or for cooking or anything else for that matter. If you allow your city the technology for a concentrated solar plant, it could produce the steam needed to power the pumps. (Note that this would restrict the pumps to pumping only in the daylight, cutting your population to less than half) It might even be possible to create a solar smelter to smelt ores, which would let you produce another thing your city is lacking: metal. [![Thermal solar plant](https://i.stack.imgur.com/ZewBO.jpg)](https://i.stack.imgur.com/ZewBO.jpg) You'd still need to import a lot of things, but heat, food and metal go a long way towards making a city self-sustaining. [Answer] Thanks to the scale, this is actually very easy. ![map](https://i.stack.imgur.com/wJbRN.png) This is the Strait of Gibraltar in the middle of a 5000 miles stretch of land (the scale might be just only so slightly off). As you can see, Gibraltar can be of any size and support any population without any problems while also being the Trade Capital of (The Rest of) The World and providing access for your two countries (just make the strait narrower and put a bridge over it). "The Atlantic" and "The Mediterranean" can supply any resources without affecting any of those countries. And a tiny strip of mild climate around the city (less than a hundred miles) won't make travel across the desert much easier. [Answer] Survival is possible but you need water. There are 3 additional ways to get water I can think of and only one is not completely crazy. 1. Build a canal. It would be extremely long and difficult to build. 2. Build an aqueduct. Still very costly. 3. Pump underground water. Use the energy of the wind to power the pumps. It is not because you are in a desert that there can't be water underground. Maybe it hasn't always been a desert and there is a lot of water accumulated deeper in the ground. The agriculture in Saudi Arabia, Libya and other countries rely on underground water to survive. They would be able to survive and grow their own food. Would they thrive? Not really. Nobody will want to travel that far in the desert to trade. Without trade, the city can't specialize in any kind of goods (food or industry) because survival (food production) will be the number one priority. That and maintaining their water infrastructure. [Answer] Unless the city has trade in some other direction and the meeting between the two nations is just an incidental thing that has nothing to do with the life of the city itself, it won't exist. The road certainly won't exist: if it's used only every 100 years, it will be buried relatively quickly. The main issue you're going to have is the traveling. Someone going 2500 miles on foot is going to take, assuming there's no issues that pop up, maybe 10 miles a day, so 250 days. But it it's a desert and there's no regular traffic, then there's low probability of having sources of resupply along the way (how do they know if an oasis is still there?). That means they need to carry their supplies with them. Assuming they're human, they'll need about two liters of water per day just to survive and stay healthy. So ignoring the extra needed due to walking (which could easily double the amount they need) and the weight of a container, each person will need about half a tonne of water (500 liters) to be carried with them. Then there's the food, their luggage, and what the animals need on top of that. For comparison, the trans-Saharan camel caravans, which would be the closest equivalent, only took 40 days and depended on regularly-maintained wells in order to do it. The Silk Road when it crossed deserts detoured to communities built around water sources and had regular traffic. [Answer] Clearly there is something different about this city. The city and its inhabitants are qualitatively different from the countries on the coasts and the people who live in them. * The city is by itself in the middle of nowhere. * The city does not involve itself in the meeting, or in huge international crises. I am reminded of Lovecraft's [Nameless City](http://www.hplovecraft.com/writings/texts/fiction/nc.aspx). > > Remote in the desert of Araby lies the nameless city, crumbling and > inarticulate, its low walls nearly hidden by the sands of uncounted > ages. It must have been thus before the first stones of Memphis were > laid, and while the bricks of Babylon were yet unbaked. There is no > legend so old as to give it a name, or to recall that it was ever > alive; but it is told of in whispers around campfires and muttered > about by grandams in the tents of sheiks, so that all the tribes shun > it without wholly knowing why. > > > This creepy city (go ahead, read about it!) was built by a prehuman race - the narrator of the story runs across their remains, as well as other things. But what if they still lived there? What if they received him as a guest? The inhabitants of the Nameless City were freaky but really (as in some of Lovecraft's best stories) they were just a different sort of people - they had their own culture, their own ways. Probably they did no harm to people, because there were no people in their time. But what if they lived into our time? The city is the last of its kind, and the race that lives there the vestige of an empire which once spanned the continent. These are a gentle, austere and somewhat forbidding people. Their ancient city thrives for reasons not obvious to the casual (and always short-term) visitor. The "people" of the Nameless City are hospitable enough to travelers, but are uninterested in the doings of the outside world. And how big is the Nameless City, exactly? How far down does it go? If for a work of fiction, that would be enough. If you need to get into the weeds and have blueprints and biology, you can make this race and their city different enough that the environment you want to have in this area is enough to let them thrive. [![max ernst - the entire city](https://i.stack.imgur.com/x57zv.jpg)](https://i.stack.imgur.com/x57zv.jpg) <http://www.max-ernst.com/the-entire-city.jsp> [Answer] ## Mining The city has to exist for some reason between 100-year meetings. One conceivable reason to have a city in such an inhospitable place is resource extraction; something that's seen many times over on real Earth. For example, [Norilsk](https://en.wikipedia.org/wiki/Norilsk) is an incredibly harsh place to live: > > Norilsk has an extremely harsh subarctic climate (Köppen Dfc), and is covered with snow for about 250–270 days a year, with snow storms for about 110–130 days. > > > [![enter image description here](https://i.stack.imgur.com/oVrdi.jpg)](https://i.stack.imgur.com/oVrdi.jpg) Yet people live there because there is nickel and palladium. What can you mine in a desert? Well according to the [USGS](https://pubs.usgs.gov/gip/deserts/minerals/), > > Some mineral deposits are formed, improved, or preserved by geologic processes that occur in arid lands as a consequence of climate. Ground water leaches ore minerals and redeposits them in zones near the water table. This leaching process concentrates these minerals as ore that can be mined. Of the 15 major types of mineral deposits in the Western Hemisphere formed by action of ground water, 13 occur in deserts. > > > Some examples of those resources are gypsum, salts, and copper. You could tweak it to be almost anything, depending on your setting. Hell, it could even be an meteorite deposit. This city can then trade its mineral resources with the two countries and any other polities that might exist. Other industries can spring up to support mining and trade. After all, you only stipulated that the two distant countries don't have regular contact, not that Desert City doesn't have regular contact. It could also grow rich charging large lodging taxes for pilgrims and other merchants. [Answer] Strong winds, with a long canyon serving as a natural channel or course. This would allow goods to be transported using kites, unattended but for possible monitoring outposts in the desert, kept supplied by the same kites. Human transport could be by hot air balloon or manned kite (neither impossible in a medieval setting) [Answer] These answers cover a large range of how the city survives and seem to solve the problems as needed. I am just adding what I see missing which is why it survives. The town between city A and city B survives based on its location. This is the reason it exists despite all the difficulties. The first thing that should be built, besides survival shelter, is a large sign. On one side it states "You are half way to A. Take a rest." and on the other side it says "You are half way to B. Take a rest." This middle town itself serves as an improvement to each of the other towns by facilitating their accessibility. ]
[Question] [ I'm trying to develop a matriarchal Empire for a story, but the main issue I'm having is that I don't want the women to all be warriors or magically physically stronger etc. The setting is essentially medieval-esque Europe and Asia, though there are differences that aren't really relevant to this question. The people of this empire are called Fayli. The Fayli have a sex ratio difference of 3:1 in favor of women, so it's quite common for groups of women to all have one husband, though rich nobles often go the opposite way and have several husbands for one woman as a way of flaunting their wealth. By matriarchy I mean that I want the women to be the diplomats/politicians, the merchants, the crafters, the architects, the religious heads, the scientists, artists/musicians and Queens/Empress...but the main thing is: I don't want them to be physically stronger or better fighters than men. The Fayli empire's armies are still made up of men, the merchant women's bodyguards are men, the miners and field workers and laborers are still men, it's just that those men always answer to women in higher positions or to their wives. As there is such a male/female ratio disparity, very often there are women who never have children, and instead stay with their sisters or move with their brothers to their new home to take care of the children. Essentially, it'd be: * Anything that needs strength or manual labor: men. * Everything else: women. Men join the woman's household and take their name when they marry, before that they live with their mothers and their extended family. Divorce is generally not a thing for men or women unless no children come of the union, because of religious reasons. Woman often live with their sisters and mother/grandmother and their husbands, sometimes sharing a husband because there's far more woman than men. Children grow up communally in large extended families and it's not shameful to bring children to workplaces. However...why would it end up this way without women having military power? If you look at how societies historically thrived/gained power, generally it came down to the military, aka, warriors. So I've seen a lot of posts/articles about matriarchal societies developing and how for them to survive/thrive outside of marginal areas (like where near-matriarchies are found today) that women would need some way of out-fighting the men, as that's where the majority of power historically has come from. However, I personally don't think this would solve the real issue when it comes to matriarchies. The real issue is not biological affinity for fighting, but rather the fact that the population of a society is determined largely by how many women of child bearing age it has. For example: Two tribes have 50 women and 50 men, one is patriarchal and one is matriarchal. Both of these tribes are vying for the same resources and end up going to war. Tribe patriarchy loses 40 men, tribe matriarchy loses 20 women. Both go home. The next year, tribe patriarchy could feasibly have 50 babies, while tribe matriarchy could only have 30. And, if during that time when tribe matriarchy is all pregnant tribe patriarchy were to attack...then they'd have no way to defend themselves unless the men were to protect them. It just seems more feasible, from an evolution standpoint, for woman not to be the fighters, so as to preserve their ability to procreate. But if they don't have some sort of magic that will allow them to win a battle against other neighboring patriarchal societies, then is a matriarchy impossible? Our own history would suggest so, as most anthropologists say there's no evidence of an unambiguously matriarchal society, and especially not one that's thrived enough to become an empire. This is what I'm really struggling with, because I just feel that it's unrealistic for women to make up the whole army of a matriarchy, even with magic fighting powers, but for men to still be in charge of the military it seems unrealistic they'd be fine being at the 'bottom of the totem pole' so to speak. I think I'm just not knowledgeable enough about why patriarchy's developed over matriarchy's in the first place, which is why I posted here. TLDR: What would make a TRUE matriarchy possible outside of 'magic fighting powers for women'? [Answer] ## The answer is in the sex ratio If as you say the that ratio is three to one in favor of women then in a medieval setting (technologically as well as culturally) there simply won't be enough males available to fill all the rolls that would otherwise be filled by men. Agriculture during this period was heavily labor intensive (as was herding, fishing and mining etc.) Add in the need for some kind of permanent or semi permanent military and law enforcement etc and there would be a chronic shortage of 'manpower'. Overtime as large cities and towns sprang up women would naturally take over and occupy all sorts of 'indoor' trades and crafts, like weaving, pottery and metal work etc even if some were male dominated originally. The need for labor would demand it. Same for administrative functions clerks and the law and such. Pretty soon 'custom' would become law. Men would bear arms, be responsible for herding/animal husbandry, mining and maritime trades and perhaps a few specialized 'heavy' trades like stone masonry. They might also be employed regularly as caravan/merchant/couriers delivering goods and messages between towns and cities and nations. This last might be important if neighboring powers have a more even sex balance and the typically chauvinist attitudes towards women prevalent in that period. The Fayli might find it politically useful for foreigners to see 'male faces' conducting business on behalf of their wives when visiting another country even if they are literally only following orders issued from home. Formal diplomatic missions to foreign courts would of course still be headed by women. The point is that in a matriarchal culture the men don't necessarily have to be or even feel like they are at 'bottom of the heap'. They are not second class citizens. Think of it like a caste system only one where status is divided vertically no horizontally. How well you do at your particular trade decrees how far you rise not what that trade is. Men have certain trades specifically reserved for them and have the same legal rights as women including the right to a share in the profits of whatever businesses their families conduct. Women run the government, banking and finances of the country as well as most trades and crafts and conduct all business within their local communities. Men join the army, sail the ships, own land/herd and travel on behalf of their families, business and government, getting paid accordingly. Importantly by tradition their input on matters relating to their areas of expertise is sought and listened to by the ruling class. Edit: If the Fayli are the only culture on the continent with the skewed sex ratio then over time intermarriage with other races might well see that ratio start to shift back towards the normal 1:1. If on the other hand all other cultures have the same issue then the need for men to travel and act as the 'face' of the Fayli for mundane business matters would not be an issue. Edit 2: Upon reflection it might be simpler if women own all the land and by law a man who herds cattle, sheep, horses etc or otherwise rent's access to land shares profits with the female owner. The same rule would apply to any other business activity. Operate a mine, the land owner gets a share. Women can lend money for movable assets (like boats) but the men operating it 'own' it. That kind of thing. Men on the other hand can own 'moveable assets' assets, livestock, boats, wagons, equipment etc and can lend money for land assets. [Answer] The men are not strategists. They are big and strong and they are attentive. But they are not strategic. I am thinking of my dog - a good dog and smart enough as dogs go. But when something is up she checks what I am doing first before she takes action. She wants direction. That is why dogs have humans. Dogs get it done fine but humans are so clever. That is how most of the men are in your society. They can put one foot in front of the other, and most do very well in the heat of the moment. They are just not big on figuring things out, and not big at all on long term planning. They look to the ladies for these things. That is why ladies are the leaders, and old ladies in particular. Men make war because males are dispensible, as you point out in the OP. Your armies of men in the field might bring one or two women with, there as strategists. When a group is all men, they are really careful and take their time making decisions. You can have a male character who can figure things out like a woman and his male companions are surprised and pleased, and sometimes tease him because of that. [Answer] Extrapolate from the Spartans <https://en.wikipedia.org/wiki/Women_in_ancient_Sparta> The women had right of inheritance, and the society was war-like; as the men died in battles the wealth, and thus the power, slowly accumulates to the women. [Answer] Rulership is unmanly Stay safe in a luxurious room taking decisions?! That is a woman's job! Manliness in this culture is deeply associated with men's superior physical strength and because of that taking any kind of work that does not involve manual labor is extremely stigmatized. Even among the military, non-combat roles tend to be filled with women as hardly any man would endure such humiliation. And on top of that... The warrior's families are in charge The rulers might not be men, but those gals surely have men to fight their wars. Their husbands are usually officers or particularly skilled warriors, while their sons form a warrior nobility, maintaining their families power, while skipping the utter humiliation of deciding trade policies and discussion immigration. This means the warrior nobility job is just fighting and making babies with probably many wives, a great deal overall. Side note 1: a skewed gender rate is unsustainable, if every men can easily find mates while women struggle, than there is an advantage to having more sons, creating a selective pressure. Side note 2: if is a medieval setting, men would still be the providers of most families. Farming was the base of the economy and it is a back-breaker occupation EDIT Side note 1 describe a biological principle. If the gender rate is 3:1 and the population is stable, the males on average have 4 offsprings while the average female only have 1,333. This mean that mutations that skew the rate in favor of more males increase biological fitness. This is the reason why even in mammals where only a handfull of males are able to reproduce, the sex rate tends to 1:1, despite most males producing no offspring the few bull produce enough offspring so that males have about as much offspring as females on average, thus having a male offspring or a female one is equally fiting. [Answer] Females control fertility. For example: Let females consciously control whether or not they conceive, AND consciously emit a substance (undetectable by the male) during intercourse that temporarily renders male impotent and sterile for, say, a month or so. * Females control their own fertility * Females exercise limited control their partners' fertility Successful males, rather than pursuing harems, abusive control, rape, and other (awful) power-based strategies must persuade a small number of potential partners that they are worthwhile mates. If they become too aggressive or controlling, they suffer a month of lost opportunity. [Answer] It's Been Done With the Iroquois The Iroquois Confederacy was a matrilineal society (inheritance was passed down from the mother's side of the family) and women had a large sway in political society. While Wikipedia has more details, the crux of the divide was that women and men both formed their own councils of government. Women would form a local council of Clan Mothers, with each mother naming a male Chief (Sachem) to the Grand Council of Sachems. If the Clan Mother disapproved of the choice of her Sachem, she could "knock his horns" (removing the ceremonial Deer antlers of leadership given to Sachems, effectively recalling them). While both councils would have to act to pass laws, the Women held the power as they could recall their Sachem and install one who did what they were told. Because the Iroquois were a confederacy of 5-6 tribes, the level of of government had Confederacy (Grand Council) > Tribal (Local Council) > Clan (Clan Mother). In times of war, Clan Mothers would declare war by naming a male "War Chief" who would lead the all male war parties into battle. Because the society was matrilineal, the Clan Mother could push the men to become warriors by declaring those that would not fight cowards and thus barring them from marriage. Women could also name diplomats (called "Pine Chiefs"). All of these positions were similarly able to be recalled if the Clan Mother felt they acted in the wrong. Essentially, it was a system where the woman were the dominant players in domestic politics but the men were charged with foreign relations duties. [Answer] The high woman to man ratio is not an answer I think. The actual problem for medieval populations was the amount of children you need to have to maintain stable population. It does not really matter how many females are there, if each one has to have (on average) 4-5 children to maintain stable population. The ratio you want is similar to what you have in a pack of lions, not very matriarchal group. Female rulers are relatively easy, especially in some sort of collegiate rule, like Iroquis Confederation. In monarchy it is more difficult, though your queen could adopt children (rather than risk men taking over during the first and any subsequent pregnancy). But full matriarchal society will be way more difficult to maintain in medievalesque tech level. What you need is not a high ratio of females to males but some biological change - you need near modern ratio of children reaching adulthood and much lower risk (again, modern like) of females dying in childbirth. In fantasy medieval society this could be achieved either by being naturally more healthy or by some sort of magical medicine. Having multiple births per pregnancy as a norm rather than rare occurrence would help as well. Reducing the risks of pregnancy and the amount of time spent pregnant per individual female would naturally give rise to more equal society and increase the likelihood of matriarchal societies. [Answer] Iroquois Confederation is said to be a matriarchy. The constitution online (<http://www.amaxpro.com/DivaLyri/IroquoisConfederacy-The-Great-Law-of-Peace.pdf>) mentions that "Lordship" is passed through the women. Only the "Lords" are members of the Council and are selected by the women who have the right. A War Chief is not a member of the Council. The confederation worked well because by working together, they had a larger fighting force than other tribes. There are other matriarchal societies around the world. A quick search can find a number of web sites on the subject. Women do not need to be the fighters in order to have power. Generally speaking, when raiding and capturing of women and taking huge risks is common, the society is patriarchal. But when a society is more stable, women come into power. Women do a better job of managing (even today, women run companies are doing better on average then men run companies). When we want a system to manage farm land for the next 500 years, we would do well to consider how matriarchal societies have been able to do that already. [Answer] The old standby: religion. Assume a society that developed a religion where communion with the deities was strictly the province of women, in a world where the skewed gender ratio meant most things that didn't require the biggest/strongest (which are statistically more likely to be men) is going to be carried out by women anyway simply because of the numbers. The society becomes more martial, using the example of Sparta, where all men are expected to be members of the warrior class. Initially, as being the primary holder of martial power, it's likely you might have men in charge, but women are going to be doing everything else: be the merchants, the educators, many of the tradespeople, and so on. And, importantly, passing on how the god(desses) expect people to properly live. One problem they'll have to avoid somehow is the agriculture trap: to keep the society fed, you need a lot of farmers making up a good chunk of the population. Pre-industrial farms depend on having a lot of kids to work those farms, but infant mortality rates were so high that a woman had to basically be pregnant all the time to have enough surviving offspring to maintain the society, which naturally has consequences for a woman's health. While upper-class women wouldn't have this issue, proportionally they'd represent only a fraction of the population so that vast majority of women a person would interact with would literally be barefoot and pregnant not because they were intentionally being oppressed but because they had to be to keep the society running, which is going to have psychological effects on people. Now, you could go the Spartan way and rely on a large slave population, which is a possibility, but there is another one: have a food crop that is ridiculously hardy, prolific, doesn't require much in the way of care, preserves easily, is easily gathered with minimal effort, and is highly nutritious so that you don't farm so much as gather in a much smaller area. This means you don't need 75-80% or more of the population being farmers to supply food, which means you have a larger non-agricultural population, which means women don't have to be kicking out kids so often, which is going to be better for their health. As others mentioned, lower infant mortality helps as well. Okay, so now you've got a situation where you have a larger non-agricultural population, freeing up more men to be able to focus strictly on warfare, but religion is considered a purely female-led province, and women are doing most other non-warfare things. Which leads to education being female led. A king might be in charge with his sword-bros who hang out with him, but women are going to be the ones keeping to society running. And since the men are often marching off to war, someone has to stay to defend the community against the random bandits and raiders, which means women, which is going to improve the prestige of women since they're not only maintaining the running of their culture, in the end they're the last defenders. It's only going to be a matter of time until some king decides it's more fun running around with the boys to raise hell in the neighbouring regions than doing all that boring governing stuff, and lo, the Head Priestess has conveniently had this revelation from the goddesses regarding that sort of thing... [Answer] In the real world, women strongly prefer to sleep with men who are self-directed and not with men who are obedient. If women were to reverse this preference, it would not take long for women to become the decision-makers in all areas of life. This would happen even more quickly and more completely if women were to openly conspire together over which men would be shown favor and which men would be incels. Within a few generations of this -- as long as women did not break rank -- the DNA of men who fail to adjust to this system would be erased from the gene pool. [Answer] Cultural Norms leading to rulership being a womens role. Men are labourers and soldiers. The lower class. Women are able to stay indoors while the men are off in the fields or at war. The women are left back in the cities, in control of trade, religion, education. They are the ones that actually keep the country running. If the men are of the raiding and pillaging variety, they may be away from home for months or years at a time; it seems only natural then that the women who stay at home and run the household/country are actually in charge. Brandon Sanderson's "Stormlight Archives" has an example of this; not a matriarchal society, but a warrior society in which women occupy all of the above roles. Men aren't even taught to read - that is women's work, most men actively don't want to do it, and a main male character is branded a heretic when he learns. The Queen's role in bureaucracy is as important as the King's role in war. You could take this to the next step - the Queen / head of the household is vital in keeping the finances running. Men don't, not because they are less intelligent or anything, it's just taboo; and they don't have time/inclination what with all the manual labour they do. If you're worried about military takeover, then extend women's role to the military: men do the soldiering, but the generals are women. This keeps the maximum number of experienced fighters on the front lines; and besides, just because you're good at swinging a sword doesn't mean you're good at directing troops or organising supply lines. Or maybe there have been attempted military coups by male generals, but the country quickly descended in to chaos as the illiterate/unskilled men try to take the places of the skilled women. After 2 or 3 failed attempts at this over the centuries, everyone knows it is better for women to do the ruling. Edit: This could be a situation that initially arises from necessity due to geography or surrounding nations. Say the Fayli nation is in land that is particularly difficult to farm. They need significantly more labour to produce food than other nations - and so the women take up more of the 'management roles' in order to free up as many men as possible for farming. Similarly, they could be surrounded by aggressive neighbours and/or be a less populous nation than those neighbours. The Fayli again have the women take up the roles of religion, governance, trade in order to allow more men in to the military. The Fayli can defend themselves by having a military force disproportionately large for their population - but women are the ones at home running the government, bureaucracy, education and trade with the rest of the population in the cities. [Answer] Your societies main hurdles are being taken seriously for trade, communication, and defense when a Queen is at the helm of the nation in the early and mid stages of their development. In the past patriarchies surrounding or recently coming form even further away nations to the new land who encountered the matriarchy would just ignore her country for these things until they relented and broke due to societal pressures created by no trade, no food, or constant defense against the outsiders who did not sign peace treaties with women. Essentially they shunned them until a King was presented to them (breaking the near or constant Queen rulership) and then even if the matriarchy had a puppet King in order the Queen over time would be given less and less access to the meetings and dealings till she was barred wholly and only the fake King had to take over and it was then deemed beneficial to allow the transition. As more outsiders did not do business with a matriarchy. The other death to a matriarchy comes in modern era via exposure to the outside world devaluing it’s system on the sole fact they have women as their leaders. Warfare can be taken on by women as well as men the Trung Sisters fought China alone with their 32 female generals and unknown many more for males as an example. As they noted in WW2 women in general are slow to want to kill but when you get them to the point they want to do so you can’t stop them. Yet we also have many women in WW2 who heard their country was going to war or it was incoming then made legal attempts the next day to join the military when that failed they'd then prioritize (1) illegally entering the military in either disguise or just walk/transport themselves there themselves (2) join a more feminine favored way to contribute to war like nurse then persuade the command on site to let them into combat, or (3) give up and find another way to help the war effort (4) start/find/join armed resistance. Their own journals (suppressed after the war by publishers) explained they had motivations of love, pride, patriotism, or protection of their homeland for their reasons. So your matriarchy will have warring Queens and Queens of peace, good, bad, and horrid, their struggle will be not be against how many women have kids in their society it’s in the patriarchies surrounding them not excluding them from trade and treaties due to them having a Queen this has killed many matriarchies. If a nation denies yours trade wound or kill them into submission. Isolation seems to be for the majority of matriarchies their best friend as war was not much a factor to them and then they were opened up to the world after all the wars in their region was done for, but this is also a reason why they are not in the modern era as well. But for the minority that did not have isolation knew when to strike, when to make peace, and when to brutalize their neighbors. Men in your society could find a limited worth in war but they’re told and shown since birth it is not a honored trait in men to be war like it is an exception a man must be put into war for necessity not for sheer fun and whim of the Queen so he should feel while he is in danger he is not being placed so without care from the Queen and society overall. And you may not see a man who leads all forces due to the political and optical glass ceiling effect put upon him. So would the matriarchy allow a man with skill to rise in a field of interest to him? Yes, but they may not glorify him like patriarchies do. This male would be odd and probably seen as a whore “he slept his way in there” or his skill is just luck that will pass. If he holds onto that position he will meet a glass ceiling that he can go no further and he will never feel like he fits in with his female co-workers nor will all of them see him as equal some will but others will not shake off their views of him as a whore or boss favorite pet. There also maybe a held back male force for national breeding the society literally will not allow x amount of men to be slain for battle. Women will be drafted though they already will make up a portion of your army maybe 40% at the start already. All women serve without exception x amount of years inservice all women know how to fight most likely groomed into this starting at age 10 or so to prepare them for whatever age you wish to use them in national defense only the men who sign up for war training consideration will know how to fight. Matriarchies prioritize women for property, resources, education, inheritance, awards, decisions, men’s aggression issues, or that women are seen as more stabilizing overall to the societies functionality, and other things not based on how many kids they can have or give to the nation. Some matriarchies may allow men in limited numbers into areas of the society while others shutter men completely as they’re deemed incapable or should remain unburdened by the trouble society can thrust onto him. [Answer] Being in leadership in the military - even at the top of the hierarchy - could be culturally considered as a role of service rather than a position of power. As long as the military leaders cannot choose who to go to war with, the real power still belongs to the women in charge who make such decisions. [Answer] There are cultures in Africa where the king and queen rule together, but have a clear separation of powers. Often the queen is responsible for domestic affairs (administration and law) while the king is responsible for foreign affairs (diplomacy and warfare). You could extrapolate from such a culture and create a similar separation in the government which then became a trendsetter for all levels of society. [Answer] As I said in comment, I disagree with the answer about sex ratio. So here is my answer, rather simple, historically accurate: War is a matter of volunteer units, trained and financed by one or two owners. The owner is at the disposal of the government. Men are at thetop of all those units. But in such a system, as in Europe during the 16th-17th centuries, military work is not well-seen. There is a famous painting about that showing a son being recruited by a soldier, and all the family is aggressive or awared by this situation. So, in your world, women have taken an important place in the society, for any reason you want. They lead the government, but military is still in the hands of men because their work as a military is not socially valuable. A similar situation could be obtained with a "Mamluk system". [Answer] You misunderstood how medieval People became (usually) military leaders If you base this off of medieval Europe: Military leaders at the time were usually nobles. Noble families (at least in the generations after enoblement) didn't stay nobles because their heads and heirs were the strongest fighters. They stayed on top because they owned and controlled important ressources, were good at politics (comes with having the ressources to afford a political education), and if they were militarily threathened, were good at raising troops to defend themselves (comes with having the ressources necessary to afford equipment and training) and were capable strategists and tacticians (comes with having the ressources to afford a military education). Have 1) a matriliniear inheritance system and female-only landownership, 2) have a man's wifes be usually related among each other, and 3) have previous military service or something related be a prerequisite for men to be allowed to marry. That keeps institutional power in female hand, solves the problem of how to have a man marry into only one family, and means that basically all your men will be members of the military at some point and have less involvement in the civilian sector. It also means 4) that the peope raising and commanding troops will be majorily women, while the bulk of the troops will be men. This means whenever you have grat losses, you're not going to loose a lot of women and therefore loose out at the repopulation game, because women will a) be a minority in your military and b) the vast majority of your female poulation will be safe at home. Another thing to think about: Standing armies were usually not a thing in the middle ages. Too expensive. In conclusion: Women in your society don't need to be stronger than men or have female exclusive magical powers. They just need to control the ressources. Therefore point 1). Justify with cultural and religious reasons as needed. [Answer] ## Just like in real life. A few years ago, Barack Obama, a feminist, was head of the USA, and head of the military. He was known for having his wife be very involved in meetings and politics and being very open to feminist proposals and ideas. He also waged several wars and had control of nuclear weapons that could destroy the world. [![enter image description here](https://i.stack.imgur.com/RWmQ1.jpg)](https://i.stack.imgur.com/RWmQ1.jpg) Have this be the norm, with female based groups having a great deal of political power. They have quotas for female politicians, they have female friendly politics. Those men that do rise up in the hierarchy have no gender loyalty, and tend to rise up to appease female voters or elites. Women would be recognized, due to the female focused politics, as being superior at a variety of tasks, and so would be dominant in areas outside of physical strength, while men could fight and die in wars and do dangerous and backbreaking work in fields. This could be reinforced by an education system that focused on teaching men how to lift things and fight and an education system for women that taught them how to be cultured and make things and talk to people. ]
[Question] [ Ork advantages: 1. Strength: orks are, on average, twice as strong as humans. 2. Reproduction: ork females rarely die in childbirth and usually have twins. 3. Height: orks can reach up to almost 8 feet tall. 4. Growth: ork children typically reach full size around 13. Human advantages: 1. Intelligence: The average ork and the average human are about the same but orks never go past that so you will never have a ork Einstein. 2. Longer life span: Orks die of old age typically in their mid-50s. 3. Psychology: Orks are slightly more competitive then humans and less cooperative. Given these advantages (especially the strength and reproductive advantage) is there a reasonable explanation for why humans haven't gone the way of the Neanderthals? Edit: They eat the same food but orks require more protein and calories. [Answer] Education You noted that orcs only get up to about human "average" intelligence, whereas humans have the whole curve above "average" to themselves. However, much more powerful than just slightly more intelligence is INFORMED intelligence. Human and Ork average joes may start with the same IQ, but what you DO with that IQ matters. Human joes spend their early years learning basic math, science, and literature, and some go on to further education in things like engineering, biology, and tactics. Ork joes spend that time learning to hunt, fight, and forage. Add all these educated average human joes to all the educated above average human joes and humanity has a major advantage, because they have the know-how to design much better defenses, weapons, and probably have an edge in manipulative negotiation when trying to avoid conflict, too. To illustrate, check out the Romans at the height of their conquest phase. The reason they were so scary is not that they had that much better weapons or that they were physically superior, it is because their TACTICS (and the design of their weapons to accompany those tactics) were superior. They fought smarter and more organized than their enemies. Put an unsuspecting small group of humans against a random similarly sized group of Orks and your humans are toast, since the Orks are bigger, stronger, and as stated earlier, spend a lot of time practicing hunting and fighting. But put a large, organized, and prepared group of humans against a large group of Orks and the Orks will have a much more difficult time of things. Basically, while the Orcs may have an advantage on the individual front, on a collective species level things are much more even. Depending on the technology and culture of the two species, there is great potential for extermination in the OPPOSITE direction, actually. [Answer] # Efficiency: Orks are inefficient. They are stronger, but generally strength comes at the expense of endurance. Humans have traditionally relied on endurance for hunting, for daily work, gathering, farming, and all the tasks that make a civilization run. Humans will use less food, produce more food, and store more food. They will be more likely to share that food with humans in need. Orks need more protein, meaning meat, which is less efficient to produce. With their large, rapidly growing populations, orks are likely to constantly be on the edge of famine. Humans are more cooperative. They need to be, to keep those children alive. But orks don't value their children if they don't either produce goods or prove themselves strong. So while infant mortality might be low, child mortality is high. For that matter, life is cheap to orks, since it CAN be. That other ork is competing with you for food. Orks are good fighters but not great soldiers. Orks are likely to view other orks as a greater threat than they do humans. Orks are short-sighted. Lack of intelligence, short lifespans, and constant suspicion of one's fellow orks means planning for the future is kind of pointless. With less value on individual children, a parent's investment in the future is diluted. Even in war, they fight to obtain resources only when the resources are already exhausted, and they fight with limited advanced planning and less benefit of experience and training. They will focus on short-term goals and quickly obtainable results. Endurance at work, cooperation in education, and long-term planning mean humans will have better equipment, tools and weapons. After all, you learn to make things, practice diligently, and make things to last. These things will not be readily stolen by orks, because orks are so much larger - the swords are small, spears the wrong proportion, handles ill-fit, etcetera. [Answer] ## Reproduction is not the bottleneck, calories are In a premodern environment, reproduction rate is not the bottleneck for population, calories are the limiting factor for carrying capacity. Thus "They eat the same food but orks require more protein and calories." is all it takes. With this in mind, any given plot of land will support more human spearmen than ork spearmen; and in a time of dire lack of food an ork will scavenge about as much food as a human, but if they'll need more food then they'll starve first. I see quite a few similarities between your description of orks and our understanding of Neanderthals. It's a fact that anatomically modern humans were not absorbed or exterminated by Neanderthals, quite the opposite. There is an assumption that we outcompeted the Neanderthals because we were more calorie-efficient and resistant to starvation, and that mattered more than their various advantages in, for example, strength. We can see this in the evolution of hominids. It would have been relatively trivial for various mutations to make us stronger, taller, faster growing or faster reproducing, however, this has not happened so apparently those mutations had a net harmful effect in the environment in which humans evolved and were selected against, probably because of the extra calorie cost. [Answer] See below my answer to a [similar question.](https://worldbuilding.stackexchange.com/a/222197/14322) See also [this answer](https://worldbuilding.stackexchange.com/questions/112099/whats-a-possible-justification-for-orcs-not-taking-over-the-world/112104#112104). The only difference is your orcs are almost as smart as humans. This is not a deal breaker however, because intelligence does not on its own determine their behaviour. It's a combination of intelligence + values that does that. And their values are different. See the second link. --- Humans/dwarfs/elves have large cities, farms and other aspects of a civilisation. Orcs have no such things. The orc-lands to the North are vast but there is no unified nation or supreme leader. The orcs live in small semi-nomadic hunter-gatherer tribes. They war with neighboring orc tribes as much as with nearby human/dwarf/elf cities. As long as our border cities have proper walls and defenses to repel a few dozen troops at a time, the orcs are not much of a problem. This raises the question of why we don't just raise an army and wipe them out. We tried this a hundred years ago but all that happened was the orcs tribes rallied to fight us. It turns out as long as a powerful foe is immediately present the tribes will stop fighting each other and fight us instead. Our army was well trained but couldn't compare with orc society where there is simply no such thing as a non-combatant. Our army was destroyed and the resulting Orc WAAAGH! rampaged to the South and destroyed three of our cities before it hit the King's River. Unable to cross, cohesion broke down and with no enemy present most of the orcs died through a combination of starvation (they had no supply trains) and infighting. Orcs are also known as prolific breeders. Twins or triplets are normal for an orc mother and an orc is full-grown by six years old. By the time we had rebuilt our cities the orc-lands had repopulated and gone back to fighting each other as though nothing had happened. [Answer] # Strength doesn't stop spears. Lots of other apes are stronger than us humans, but we're the dominant species. Human cooperation and intellect tends to mean humans are much better armed and able to fight in groups, which is enough to kill orcs. It would be extremely dangerous if someone sold weapons to orcs and they were able to rally behind a warchief, of course. [Answer] ### Cooperation and learning from the smart people floats everyone's boats higher Think of the resources available to a modern human. Could you or I independently invent an internal combustion engine, and everything that goes along with it? Of course not - but once one super-smart person has figured out how to do it, less-smart people can copy it, and even well-below-average people can use it. People have actually seen this happen with tool-using species like crows, where one super-smart crow works out a strategy such as using a bent hook to extract food, or placing nuts in front of stationary cars so that the car crushes the shell for them. It needs one bird to invent the trick, but the others can see it and copy it. The defining feature of humans isn't strength or anything like that, it's the ability to learn and refine ideas from other humans. Want somewhere to get out of the weather? Find a cave. Want to protect yourself at night? Block the cave entrance. You're somewhere without caves? Build a hut, and build a palisade around it. Want to get more nutritional benefits? Light a fire. Want to kill animals bigger than you? Make a spear. Want to kill things at a distance? Spear again. Want to kill things at a much greater distance? Make a bow, or a spear thrower, or a sling. The moment the first human invents the first spear, the orks lose. [Answer] ## Humans are more social, we collect in larger groups. This may very well be the reason humans won out over neanderthal, who were larger, stronger, and tougher. Human had no physical advantages over neanderthal. And technology was not that different for most of their contact. But the average neanderthal tribe was around 10-30 individuals. while human bands range from 30-150. These are both controlled by how big a certain part of the brain is(likely the neocortex), basically how many other people we can keep track of. This is not a function of reproductive rate but just how social your species is. if a a group grow too large it splits into two separate groups. Orcs may breed faster but if they attack in groups of 10-20 they will basically always lose to a human hunter gatherer band of a hundred or more. They can pick off lone humans easily enough but as soon as it becomes large scale conflict they always lose. Strength is all well and good but it can't make up for nearly an order of magnitude more enemies. Once humans start forming villages and cities the difference just becomes more exaggerated. A chieftain leading multiple bands in a single force of over a hundred orcs will have a hard time taking a city of thousands. This difference does not have to be that extreme if human groups are about twice the size they will be hard to beat but not so hard humans can just steam roll over the orcs and wipe them out entirely. you can also add an idea from the man kzin wars, the kzin being almost all warriors and ruled by warriors get too worked up and always attack too early. Orcs always give themselves away by attacking lone stragglers so humans always have a chance to prepare. [Answer] # Experts and Agriculture On the most part, humans are slow-growing and fussy, but they have uses. Uses that ensure the orcs never let them go extinct, even though the humans may try to accomplish this now and then as one means of rebellion. Orcs test the intelligence of human infants early and often. The ones who make it through the spear trap and the razor pinwheel are moved into Special Bunking, which is to say, out of earshot of other humans that would poison them against the Orcs. The humans are told that they are special, malformed Orks with a brilliant role to play, designing siege engines and flaming ballistas and all manner of things that the average person can understand how to use, but not really the best way to make. Every few years they are transferred to higher-level academies, except for the lower half of the class that goes to the same fate as other humans. And the other humans? They're still valuable meat byproducts. They taste a dang sight better than Orc... heck, anything tastes better than Orc, even the dreck at the bottom of the outhouse; otherwise they'd eat each other... but humans are a serious competitor for pork and beef. So it's not all a loss when they fail their finals. [Answer] # Multiple factors And there will be synergies; how these play out depends on the discretion of the author, so I'll leave these to everybody's imagination. Also, I'm working off the question as currently stated; the outcome can be affected by more traits - e.g. parts of this answer would shift if due to differences in healing rage, or resilience to parasites and infections, amount of xenophobic tendencies towards their own species (e.g. humans tend to restrict cooperation to humans they consider to "belong to us", Orks may be more or less xenophobic), etc. etc. etc. ## Calories difference Orks require more calories, which is the limiting factor. Orks typically having twins, not dieing to childbirth and (most importantly) growing up faster means that they reproduce to a land's population capacity much faster than humans, but their overall capacity will be lower than that of humans. This means that uninhabited areas will be quickly flooded with Orks once they reach it, but once the Orks find human-inhabited land, they will find themselves outnumbered. It also means that after a catastrophe, Ork population will replenish a few years earlier than human population. So you get this dynamics: Orks will get there first, but will start to get driven back - slowly - as soon as they find humans. After a catastrophe that hits both populations in an area, the Orks will be back to fighting conditions anywhere between 5 and 25 years before the humans, which means that the Orks will overrun the humans. (Exception: A lot depends on how many immigrants the catastrophe-affected Ork and human populations will allow and attract, and in what timeframe immigrants can come and integrate.) ## Intelligence Does not affect the dynamics much, unless with an empire that is long-lived and makes a point of collecting knowledge like real-world civilisations do. Note that collecting knowledge is not a universal trait of human societies. E.g. Byzantium was about the only empire that did so for a long time, and it took the Muslim states centuries to (a) catch up and (b) finally overwhelm Constantinopolis with higher numbers. And building up a high enough knowledge and technology advantage to actually matter is a matter of centuries; I personally think that no society actively worked towards building up knowledge just to gain an edge, there is always some other motivation behind it. (Possibly with an exception in the "Age of Enlightenment", where technological advantage was motivating some but not all of the people who drove that knowledge-collecting frenzy. Once this produced tangible results, states became interested in driving this more.) Also, a highly intelligent individual won't make any of their intelligence unless the society values the trait, trains them, and can afford to feed them even though they do not contribute to the economy directly. In societies that do not value intelligence, the intelligent persons will likely use it for their own purposes - become a leader of some sort, i.e. to gain power (be it military or religious), to gain personal wealth (in societies that allow this), or anything else they want. So the author can freely choose how much of an effect this intelligence ceiling will have. Note that Orks will still be able to replicate much of human technology; they just won't be able to understand everything, and the poorly or not understood parts of human technology will be considered "human magicks", possibly "filthy human magicks". ## Cooperation More competition, less cooperation means that more Orks will die or be crippled than humans, with obvious consequences for reproduction rate, economical power, battlefield discipline, post-battle recovery rates, etc. There is a strong leverage, e.g. minimal differences cause small, easily overlooked effects, notable differences cause obvious effects, strong differences cause massive effects. Still, the author can dial this up or down at will. It's unlikely that an Ork will connect the dots. A human with enough intelligence and data may find that out. (The data-gathering part will be the more challenging task, actually.) Cooperation/competition is a very strong influence, but the author can essentially dial this up or down as intended - minimal differences cause notable effects, notable differences cause obvious effects, obvious differences cause strong effects, etc. [Answer] I think you could also easily ask "Why hasn't [some group of humans] exterminated or absorbed all other groups of humans?" Why didn't Xerxes expand his empire around the entire globe? What stopped The Golden Horde? What about Rome? Why didn't The British Empire eventually just make the whole world effectively part of Britain? Didn't Germany try something once or twice? History is full of attempts by one group of humans to absorb or eliminate every other group they can get their hands on, but it always falls apart in the long run, for a variety of reasons, not the least of which is that the unifying sentiment driving the entire thing isn't enduring enough or spread so easily. (Even in the colonization of the Americas, we didn't end up with some big "unified America". We ended up with lots of different countries between North, Central and South America and they don't all like each other.) It's easy to imagine orks being like this, except worse, because I can't think of an example fiction where orks are kept in control by anything less than absolute might of some supreme ruler and if his power ever fails, the orks immediately turn on each other in a power vaccuum and the global conquest turns into warlords and tribal fighting. If humans can't easily bring themselves together to form a unified global civilization, I wouldn't think the standard fantasy ork has a chance. Incidentally, this would also explain why the humans never wiped out the orks. "At last we have freed these plains of orks. Glory be to King Alfred, that these lands are now his!" "What! I think you mean King Ferdinand!" ...and it all goes downhill from there. tl;dr summary: there are loads of factors that go into wars, and being bigger, stronger and more prolific isn't automatically enough to offset every other major factor. [Answer] # Niche partitioning Orks are large, strong, mesocarnivorous. They live nomadically and are conventionally hunter-gatherers, emphasis on the hunt. Humans, as you note, are smaller and have a higher ceiling for intelligence. They tend to settle down in areas, build strong structures, and subsist on agriculture. Wandering ork tribes are absolutely a concern, but human settlements are quite well-defended, both with strong architecture and weapons, so it's not generally worth the trouble to raid them unless the straits are dire. Humans tend not to bother orks so as not to draw their wrath unnecessarily. Humans and neanderthals mostly occupied the same niche, so the competitive exclusion principle kicked in and H. sapiens won. Here, H. sapiens and H. orkus can coexist outside of direct competition. [Answer] # Intelligence Simply put, the humans are going to progress further technologically then your orcs. Humans will have fire, strategy, sharper tools, more durable tools, siege weapons, and fortifications long before the orcs do. # Resources Since your orcs calorie intake is higher than the average human, if your orcs don’t figure out that they can cook or grow food, the orcs will simply starve. They will not be able to suppport a war campaign against humans. There also wouldn’t be enough space for both species. # Conclusion Humans will be your problem, not orcs. Since the orcs live for less time, are dumber, and won’t advance as fast, you will have to find a reason as to why the orcs don’t get wiped out. Best way for that would be to limit the overall technological advancement to Iron Age. Even though your orcs have numbers, look at the Battle of the Somme (world war I) to see your answer as to why the orcs couldn’t overwhelm the big brain humans. [Answer] Technologies It is much more difficult to do research and discover a technology than later use it. Assuming that doing research, converting results of research into technical ideas and building first working prototypes highly benefit from more experience and intelligence, humans would have advantages of having some 60 year old professor with significantly above-average intelligence and now also lots of experience. Such people can discover technologies that do not require as much of intelligence and experience for they later usage, mass production or incremental only improvement. Also, such bright experienced people would have impact even when making only few percent of the population. Technologies may improve agriculture and provide better weapons, or more/cheaper weapons of the same good quality. This would give notable advantages in the competition for resources and survival. [Answer] Infighting The orcs could hold more of the planet (or continent) but their tribes (or states) tend to turn on each other when any one gets too strong - or the stronger one eats a smaller tribe which unites all the other orc tribes against them. Human's tend to band together very well when faced with an external threat. Its possible that the remaining human tribes (states) make a point to never weaken each other and immediately band together when one of the orcish factions attack them - as well as making sure to never provoke the ire or the larger orcish factions. Incompatible resource consumption/ allergies Its possible that the stuff that orcs eat (and the plants that make up their very biomes) are toxic to humans (and visa-versa). So while there may be resources in human territory which orcs want, orcs find it extremely to inhabit those areas for extended periods of time. So orcs may rely on humans to mine areas toxic to them so they can go exert their physical dominance elsewhere. [Answer] Also Humans adapt better to different conditions while orcs trive only in places where simple hunting techniques are enough for survival. ]
[Question] [ Background World has had a disaster that has caused a global breakdown of society, along the lines of Fallout or The Walking Dead (90% of people have died or been turned into flesh-hungry zombies.) In the five years following this society-changing event a number of settlements, camps and towns have appeared. These settlements are mostly self sufficient but are often threatened by bandits, raiders and hordes of infected that roam the land. One group have decided to solve this problem by having a paramilitary force that will protect settlements and towns against these threats. This group is not self sufficient and has to scavenge what they can without infringing on settlements. Question How can this paramilitary police force fund its supplies from settlements without using blackmail or extortion? [Answer] Imagine a civilised world, where every individual pays protection money to the 'local' gang (local in this case meaning a single gang's territory can cover hundreds or even thousands of miles) on threat of kidnapping or theft of property. In exchange the gang provides protection from other gangs and even other individuals within their protection racket who break whatever rules the gang has set in place. This may sound far-fetched, but if you squint hard enough, this describes every government. You pay taxes on threat of arrest or fines, and in exchange the government provides law enforcement and military force in your defence. Thus all you need is for each town/village to negotiate a fee with your paramilitary group. In exchange for supplies, your paramilitary will provide protection. The amount of supplies offered will naturally affect the scale of protection provided. Just be careful to avoid having your paramilitary raid towns outside of their purview and to actually protect those with in it, so as to avoid those accusations of extortion. [Answer] It depends on what you call "blackmail" The simple answer would be that the settlements would be happy to share some of their resources in exchange for protection. If they're not willing to share, they wouldn't be protected. I would not consider this blackmail any more than I consider a security guard's wages blackmail. It would be blackmail if the paramilitary force in question would not leave any choice to the settlements, ie: the main protection would be from the paramilitary force itself. That would be extortion (and standard mafia practice) [Answer] ## The military has far more to offer than "protection" Each of the following items can be offered to individuals or communities, and can be either paid for in advance or as they are used, in trade for whatever the military needs. * Health care. The military has trained personnel, medicine, supplies, and facilities to deal with emergencies and disease. * Transportation. The military has vehicles, fuel, and maintenance personnel which allow the transport of people and goods. In fact, the military could act as the merchants between villages. * Communication. For example, from one village to another. * Construction and repair of buildings, equipment, etc. * A better ability to scavenge what they need, than your average person. * Knowledge of advanced subjects (engineering, medicine, etc.) than your average person, and the means to preserve such knowledge. * A neutral third party, to resolve disputes. In other words, a court system. * A guarantor of democracy. In some countries, the military has a tradition of upholding free and fair elections (e.g. [Kemalism](https://en.wikipedia.org/wiki/Kemalism)). These apply more to the military than to police. [Answer] A religious military order The group could be something on the same fashion of the Knights Templar, being at the same time a religious and military order to whom people seek not only for protection, but also spiritual support. This way people would not be only paying for a service, but donating for a religious group as a way to atone for their sins. Even very poor people would be willing to give, in order for a better future in heavens or in the next life. [Answer] These paramilitaries are able to scavenge from the fallen world. Sensible people do not stray far from the relative safety of cities. The world has become weird and bad. If you want to roam the wasteland, looking for old technology or salable items, you will need to be heavily armed and ready to fight. This is the origin of your paramilitaries - they are badass treasure hunters, looking for relics and things of worth in the ruins. They need to be ready to fight monsters and also competing groups of humans. This skill set, once developed, means that branching out into the protection racket is not that difficult. [Answer] A common goal Nobody in the society wants to be eaten by zombies. The easiest way to survive is to pool your resources with other survivors. Together, a group can fend off a zombie hoard, but alone, they would quickly die. The society has enough people to scavenge and defend themselves. In a smaller group, with say 3 people, you could only do one at a time effectively. Two people alone cannot beat off the horde, and it will take two people too long to scavenge, to the point where they will starve. The societies are always looking to merge and recruit new members because no one can survive on their own. [Answer] "Without infringing on settlements." You need to decide on whether this police / paramilitary force is aiming for 'good' / lawful, or for 'evil' (or even 'good in their own eyes but evil to everyone else') The tone of your question suggests that the original aim is for 'good' / lawful - along the lines of the Knights Templar model suggested in another post Then you need to decide what happens to these who can't pay / won't pay. Are they asked to leave? Are they forced to pay? Are they allowed to stay but the police force makes it known these people are NOT under their protection? What happens if there are rogue elements within the police force? What's to prevent the leader of the police taking over the leadership and becoming the King? \\ Plenty of scope for tension. \\ (This happens frequently in history - see the Romans, Kings vs Popes vs powerful Barons etc, and even in modern times - Thailand, various African countries, etc. You could even claim the Eisenhower presidency was a soft government take-over by the former Supreme Commander of the combined US / NATO military forces.) [Answer] Several answers refer to mediaeval era, but none mention Arthur—not the fictional king, but the more realistic military leader. His army, which we would probably call a war band at best, was still too large for any regional feudal lord to support permanently. The solution? Arthur moved between Mercia, Powys, Gwent and other early kingdoms, never outstaying his welcome and earning himself a bit of a reputation in the process. Granted, the historicity of this account is disputed, but I've read versions of it by several authors. John Morris's The Age of Arthur: A History of the British Isles from 350 to 650, is a good starting point. Apology, this should really be a comment, but I haven't the required rep. [Answer] It would be a subscription based service. The town or settlement would pay this police, or paramilitary force in supplies; weapons, ammunition, food, etcetera, in exchange for their protection. The bottom line is, since I assume money would be essentially worthless in this world, the bartering system would be used instead. [Answer] ## This is how the feudal society began Once upon a time there was this great civilised empire, named the Roman Empire. It lasted for quite some time, six to eight centuries, depending on how one counts, but eventually its internal contradictions prevailed, and it split into a poor and unstable western half and a rich and stable eastern half, and in the 5th century the western half fell to pieces. The economy of the fallen western half of the empire crashed, and the population shrank, and the remaining people lived in small, almost isolated and almost self-sufficient communities. And in this fallen world some strongmen had the idea of providing protection and a semblance of safety and a sort of justice, in exchange for food and clothes and, most importantly, fealty. Their position was naturally inherited by their heirs, and lo and behold, just two or three centuries later their descendants became known as noble feudal lords. (And of course the economic basis of the society changed too, with money becoming scarce, and trade shrinking to a shadow of its former importance. For the society was pulverised into a multitude of feudal domains, which ate what they grew, and clothed in fabrics made from the wool of their sheep, and seldom if ever had any surplus produce to sell abroad.) The bonds of fealty worked both ways, with the vassal owing consilium et auxilium, advice and support, to his lord, and the lord owing protection to his vassal. And this hierarchical society where every man owed fealty to some other man and so on up to the top where the king or duke sat endured for about a thousand years, which period is commonly known as the Middle Ages. [Answer] This will depend on whether this paramilitary force is affiliated with one (possibly the largest) settlement, or has to stay independent from any settlements' leaders. If this force is based on one settlement, then we have a NATO model, where American military is the dominant component of the joint force, while American economy is bearing the heaviest cost. The government of this biggest settlement may ask/demand/threaten other settlements to make substantial contribution to maintain this force, or else they will be on their own. If this force is independent from any settlements, then, initially, settlements would provide resources to fund this force, but later the force may need to find its own sources of funding, likely taking on mercenary missions. Settlements will pay for a mission when they feel threatened. The risk of this second model is that this force would become dominant among the settlements it thought to protect, and its commander would not be able to resist the temptation to become a king of this settlement confederation. [Answer] Police auctions Police auctions are a thing in some countries, where a police department sells off a variety of items to profit its own budget. In a post-apocalyptic world, you probably don't have to worry much about the legal framework for it, so pretty much anything it gets its hands on and doesn't have to return, it can keep (if you seize a big armoured vehicle for instance) or sell (if you seize a box of wooden sticks). So what are you going to keep/sell then? * Surplus. Decommissioned equipment that can be safely transferred to the public (cars, radios, computers, maybe even guns). * Lost and found. Items that nobody claimed after a period of time. That includes items from dead people with no known next of kin. It might also include unclaimed evidence after an investigation is closed. * Ill-gotten goods. Once whichever semblance of justice system determines the guilt of people, you can seize their assets. How much you seize and what's the baseline crime for a seizure is up to you. It has all sorts of interesting moral considerations, such as how it affects the innocent (e.g. do you make a family homeless for the crimes of the mother) and how it can warp investigation towards people with the most possessions (e.g. do you plant evidence to upgrade a misdemeanour into a crime and claim that sweet SUV for yourself). [Answer] By getting paying customers. Just sell subscriptions. The Machinery of Freedom: <https://www.youtube.com/watch?v=jTYkdEU_B4o> <http://daviddfriedman.com/The_Machinery_of_Freedom_.pdf> Law Without Government: <https://www.youtube.com/watch?v=8kPyrq6SEL0> Legal Systems Very Different From Our Own * Iceland: <http://www.daviddfriedman.com/Academic/Course_Pages/Legal_Systems_Very_Different_13/Book_Draft/Systems/SagaPeriodIceland.htm> * Xeer: <http://www.daviddfriedman.com/Academic/Course_Pages/Legal_Systems_Very_Different_13/Book_Draft/Systems/SomaliLawChapter.html> Chaos Theory: <https://mises.org/sites/default/files/Chaos%20Theory_2.pdf> ]
[Question] [ World I'm building a sports league. The sports league has 21 teams. This led me to a question that's an interesting intellectual puzzle I thought this forum would like: Could the 21 teams wear different strips/kits/colours? They would have to be distinguishable at a glance. Say you want 6 teams to have visually distinct kits, that's easy: you have a black, white, red, yellow, green, blue team. The more you have the harder it becomes. (Obviously real teams just have an alternative kit they wear when there's a danger of confusion. I'm trying to avoid that because it makes them less strongly branded, weakens their sense of identity that little bit.) Searching led me to this [List of 20 Simple, Distinct Colors](https://sashamaps.net/docs/resources/20-colors/). Let me draw your attention to the 'Convenient' ordering at the top. ("I’ve arranged the “convenient” order so that if you want six colors, for example, just choose the first six. The order of the colors is inspired by their frequency of appearance on all the world’s subway maps (yes, I did count them all!)") So you might say: "Well there you have it, 20 distinct colours, use those." But A) they're not quite distinct enough (the list includes green, lime, and mint), and B) that list was built with a constraint we don't have: we don't have to have one colour. A team with a red strip like Arsenal is distinguishable from a team with red-and-black stripes like AC Milan, (IMO: maybe someone will argue). You don't have to use a new colour to create a new strip. There's also shapes to think about. Imagine Team A has yellow-and-black vertical stripes, and Team B orange-and-black vertical stripes, that's a problem. But if we make one team's stripes horizontal instead of vertical, that helps a bit. [Contrasting colours](https://en.wikipedia.org/wiki/Complementary_colors) might be useful here: a team in blue-and-yellow can play against either a team in blue or a team in yellow without a problem. [Answer] This problem was effectively solved at the end of the 18th century with [Naval Signalling Flags](http://www.gwpda.org/naval/s0100000.htm). There were experiments to see which contrasts were visible and which were not. There are no green flags, for example, as the difference between green and blue was hard to spot, particularly with changing lighting at sunset. [![Alphabetical flags](https://i.stack.imgur.com/lGD5H.png)](https://i.stack.imgur.com/lGD5H.png) The 26 letters allowed you to spell words, but you were also limited by the flags in your locker and the space on your mast. The flags were supplemented by national flags, and telegraphic codes using rarely-used letters. See, for example how the famous [England Expects...](https://en.wikipedia.org/wiki/England_expects_that_every_man_will_do_his_duty) signal sent by Nelson was a compromise between the message, the flags they had in the signal locker, and the telegraph codes. The upshot is that each of the 26 letters had to be distinguishable in isolation (unlike letters, which can often be guessed from the surrounding ones). Flags fulfilled much of the requirements for a sports kit. The flags had to be readable in any orientation, and under different lighting conditions. [Answer] Having played with it a bit, I'm pretty sure it is possible. I'll give my answer in visual form first, then talk through it – [![enter image description here](https://i.stack.imgur.com/0r5xx.png)](https://i.stack.imgur.com/0r5xx.png) We can use 7 colours simply, without needing to mix: Black, White, Green, Yellow, Red, Royal blue, Sky blue I shied away from using orange alone: a tricky colour which is adjacent to both red and yellow. Magenta/pinks are too close to red, and there's no reason not to add a second colour to pink to help the matter. Maroon alone could work (by 'work' I mean 'have sufficient contrast with red) – take a look – [![red and maroon](https://i.stack.imgur.com/ZeWhE.jpg)](https://i.stack.imgur.com/ZeWhE.jpg) – but it's better to add a contrasting colour. --- Second, I started tapping the idea of [contrasting colours](https://en.wikipedia.org/wiki/Complementary_colors). You can have a yellow-and-purple team because that contrasts strongly against both yellow and purple. (You couldn't have a blue-and-purple team.) This give four extra teams: green&red, orange&blue, yellow&purple, black&white. I made orange&blue and yellow&purple two different patterns, as they have limited contrast (orange is like yellow, blue is like purple). --- We haven't utilised maroon yet. What contrasts with maroon? Blue. So put West Ham in the league. --- Red&green are considered opposite colours, maximum contrast on the colour wheel. But red&yellow is also very highly contrasting. [This guide to contrast for web design helped me](https://www.lifewire.com/contrasting-foreground-background-colors-4061363) --- Looking through the list of 20 colours, I'd skipped brown, beige, olive, and grey as being too weak alone. So throw them all together! And what does that make? Camo, more or less. Add a camo team; that's very different from green. --- This is getting close to 100% optimal. The problem is tractable. A colour normally only has one or two potential clashes, so you just need to make it distinct from those with some alteration. [Answer] With $N$ colors and $M$ different articles of clothing to color, you can create $N^M$ unique kit combinations. If the uniform consists of shirts, pants, and shoes, you need only 3 unique colors to have 27 unique color combinations. If the uniform consists of just shirts and pants, you need 6 colors to yield 36 unique color combinations. We can certainly get 6 unique enough colors (white, black, red, blue, yellow, green), the only question becomes is a red-blue team distinct enough from a blue-red team. If it's not, we can simply double the number of possible kits by adding stripes to all kits to make new kits. Add in color-able embellishments like stripes and their directionality, and the number of possible kit combinations grows very quickly. 21 unique combinations is quite doable even with relatively few distinct colors and limited options for what to color - the only way it's really not feasible is if the uniform must be a single color. [Answer] Below I use the term livery in most places, as this is the most generic terminology for what you’re trying to talk about. It encompass not just the colors, but also the patterns, insignias, and even things like the exact style of outfit. --- # First, a frame challenge: Alternate livery doesn’t really hurt branding all that much. I encourage you to look at how alternative livery is actually used in real life. In a majority of cases, a team’s primary livery is used in almost all cases, they just use different colors on their uniforms during a match, and the primary purpose is so that the two teams can be clearly distinguished while playing. While the alternative livery is often distinguished in many sports by being ‘away colors’, or an ‘away uniform’, that distinction only really exists because if a team needs to change livery for a match, it’s by convention always the team that is not hosting. Yes, there’s some loss of visual distinctiveness when watching a broadcast of a match, and you may have to check the scoreboard or something equivalent to know for sure who is playing, but that’s about it when it comes to the alternate livery hurting branding. Additionally, alternative livery helps with merchandising (because it gives you a wider variety of things to sell). This may be significant if the teams derive at least part of their funding from selling merchandise. --- # Second, an actual solution. Pick seven distinct colors. Each team gets a unique set of three from that list of seven. Problem solved. There are 35 possible combinations of 3 colors selected out of 7 possibilities, so this scales up to 35 teams (which helpfully lets you ‘retire’ combinations when a teams are disbanded, allowing for better consistency across such transitions). Each team will have a unique set of colors, so the entire rest of the livery, including things like patterns, can actually be identical (though it shouldn’t be identical for a couple of reasons, such as pattern recognition being important for quick identification even if the colors are distinctive). In terms of distinctiveness, I would probably go with (using the swatches on the site you referenced) white, black, red, yellow, green, blue, and one of orange, cyan, or magenta. That gets you clear visual distinctiveness of each color, while still being reasonably distinctive even for people with color blindness. Overall though, this requires the league to assign colors as opposed to the teams just picking their own colors, because cultural bias will tend towards specific colors being picked. You’ll notice for example that red is a very common color for sports teams in Western cultures because of it’s associations with feelings of aggression (in the sense of aggressive competitiveness more than violence, though for some sports the violence aspect fits too). [Answer] Color combos Every real sports league has this problem. What most of them do is to have teams pick a primary, secondary, and tertiary color. Jerseys are usually the primary (home jersey) or secondary/tertiary (away jersey). Often one of the secondary or tertiary colors is white or black and mainly used for shadow or extra contrast. You could also try patterns, like Tartan cloth, which is a similar idea. [Answer] ## Culture is a bigger obstacle than mathematics Mathematically, this issue can be solved using the combination formula: > > C(n,r) = n!/((n-r)!\r!) > > > Most people can consistently distinguish by name and on sight 14 colors [Black, Grey, White, Red, Dark-Red(AKA: Maroon or Burgundy), Yellow, Gold, Orange, Brown, Green, Blue-Green (AKA: Teal, Aqua, Cyan, etc.), Blue, Purple, and Pink]. Even nearly color blind people can tell the difference between black, white, red, green, blue, and gold. This gives you somewhere between 6-14 colors to work with depending on how handicap accessible you want your team kits to be. Now let's assume that kits can have anywhere from 1-3 of these colors. For a 6 color system you get: > > Cx* = C(6,1) + C(6,2) +C(6,3) = 6!/(1!(6-1)!) + 6!/(1!(6-1)!) + 6!/(1!(6-1)!) > > > Cx = 5 + 15 + 20 > > > Cx = 40 > > > And for a 14 color system you get: > > Cx = C(14,1) + C(14,2) +C(14,3) = 14!/(1!(14-1)!) + 14!/(1!(14-1)!) + 14!/(1!(14-1)!) > > > Cx = 14 + 91 + 364 > > > Cx = 469 > > > So, by just using colors in combination of 3 or less, you can support a league of 40-469 easily distinguished teams without any conflicts. ### ... So why then is this such a big problem for major sports leagues? The reason most sports leagues have issues in not a lack of available combinations, but because some colors are just a lot more popular than others. For example: despite all of the colors to choose from, 88% of the teams in the NFL use black, blue, or red as one of their colors. 40% of the teams use 2 of these colors and 1 team uses all 3. In contrast, colors like teal, brown, and burgundy are only used by 1 team each and not a single team uses pink despite it being such a popular and recognizable color in other contexts. With this much overlap, it can get hard to tell who is who not because there is not enough colors, but because there is a strong cultural bias that causes most of the teams to gravitate towards these same 3 colors. This is because in Western culture, black is highly associated with masculinity, red with aggression, and blue with comradery: The 3 principle virtues of the male athlete. In contrast: pink and teal are typically seen as more feminine colors and brown and burgundy are humble colors which goes against the typical virtues of an athlete. In other words, if you want to get all of your teams to look different, it has to be through acts of regulation that force them to pick from an even distributions of colors instead of letting the teams pick their own colors. So, if you let the league assign colors instead of letting teams pick them, you could easily have 21 teams that each look uniquely deferent without needing separate home/away uniforms or other secondary features to distinguish them. [Answer] It's easy. Just use whatever colour you want so long as you have 11 distinct jerseys. Some plain, some striped, it doesn't matter. Then do the rest by changing the shorts/skirt colours. You might have a grey and white striped jersey thats similar to a blue and white one. But the red shorts, versus the green tell you which is which at a glance. [Answer] Main colors are red, orange, yellow, green, blue, purple. Black and white are not considered technically colors but they are distinct. So that makes about 8 main and distinct colors. So some teams might have both shirts and pants the same color. That makes eight teams. Other teams might use different colors for shirts and pants. Eight times eight is sixty four. If a team with red shirts and purple pants and a team with purple shirts and red pants are counted as having different color combination then there are one hundred twenty eight two color combinations in addition to the eight color combinations. In heraldry white and yellow are counted as the metals silver and gold, and red, blue, green, purple, and black are counted as the colors. Two colors or two metals can be placed side by side in a pattern, but a color can not be placed upon a color, nor a metal upon a metal, to ensure sufficient contrast. Thus using heraldic colors there would be ten color combinations, or twenty if a black shirt and gold pants are considered different from a gold shirt and black pants. And that is with the shirts and pants being the same color all over instead of having patterns or having images in a different color on them. In medieval warfare being able to recognize the heraldic designs on shields, surcoats, and banners at a distance to tell friend from foe could be a matter of life and death, so if the members of team wear their coat of arms or their heraldic badge in a large size on their clothing it should be easy enough to tell who is who. If the sports players and fans know the rules of whatever heraldry like system your society uses, Someone could described the heraldry of a team in a sentence or two and the people who hear that description will be able to recognize it at first sight from the description. There is a figurative expression "draped in the flag" for someone who claims to be so patriotic that you can picture them wearing the flag wrapped around them. (Which can be literally true if someone has a coat of arms and banner of that coat of arms and wears clothing with the coat of arms on the clothing, the same pattern as on their banner.) And of course it is entirely possible for sports teams in our world to have their flags. Thus fictional sports teams might have their flags, and the uniforms of players might have their flags printed on them. [Answer] Solved in real world When a sporting event includes multiple teams simultaneously, their attires have to all be different: [![Formula One cars in multiple liveries](https://i.stack.imgur.com/MR9hc.jpg)](https://i.stack.imgur.com/MR9hc.jpg) (Morio, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:2010_Malaysian_GP_opening_lap.jpg)) The use of patterns, sponsor names and logos distinguishes the teams well enough for a profitable sport. There are 10 teams in Formula 1 and 17 in NASCAR, close to your parameters. ]
[Question] [ If a great division occurs, sealing two warring cultures apart for many generations, my only explanation so far is a tectonic shift. I imagine water flooding between a long split. But as I understand it such shifts are quite slow and wouldn't fit the context of the story, wherein being "locked" on the wrong side is needed. Can this natural phenomenon happen within say a week? [Answer] Not within a week, but within a few weeks it is. It is true the movement of plates is very slow, but flooding can happen remarkably fast. Rift valleys are rarely impassible—that is, until they flood and stop being valleys and start being seas. If you have lowlands suddenly joined to the ocean, a few weeks to fill is possible. The Mediterranean ([Zanclean](https://www.sciencedirect.com/science/article/pii/S0031018215000735?via%3Dihub)) flood is a good example as is the Bonneville flood. At one time you could walk from Italy to Sicily to Tunisia (Africa); within a few weeks there was a sea in the way. When Gibraltar breached, the ocean flooded into the the lowland; some estimates put the flooding at over 100,000,000 cubic metres per second. Erosion turned a tiny breach into a huge gaping chasm in minutes. The flooding was also incredibly noisy; I remember one claim that noise might have deafened local wildlife. Afterwards there was a sea where there had been crossable land before. On a more local level, one day you could walk from Spain to Africa via Gibraltar, then one day the ocean breached and the mother of all waterfalls cut through rock like butter creating a raging waterfall-filled chasm eventually replaced by ocean. Note you can make a fictional basin even easier to make impassable, the mediterranean is a wide deep basin. Completely filling the mediterranean took two years, but a properly shaped basin (something shaped like the red sea) could become complete uncrossable within 4-5 weeks. Especially if there are pre-existing Saline lakes and crossable highlands that get cut. [![enter image description here](https://i.stack.imgur.com/wVSmq.jpg)](https://i.stack.imgur.com/wVSmq.jpg) [![enter image description here](https://i.stack.imgur.com/I0N9A.jpg)](https://i.stack.imgur.com/I0N9A.jpg) [Answer] # Yes, and it can happen extremely quickly! For example, there is the process of Rapid Non-Catastrophic Tectonic Shift. There are, as the geologers know, deep under this world, gigantic Beings whose atlantean job it is to uold up the surface world, the continents and the oceans, so that they won't sink down into the molten layer deep below. [![enter image description here](https://i.stack.imgur.com/CPl3V.jpg)](https://i.stack.imgur.com/CPl3V.jpg) Whenever these great Beings become annoyed or agitated, that they began to shift about most uncomfortably. Usually, the result is an ordinary earthquake. These occur when one of the Beings shifts its shoulders or scratches its leg. The overall integrity of the crustal structure is relatively unaffected. However, if the agitation is simply unbearable, some Beings in a given area may abandon their posts or lay down and curl up in order to seek relief from what's troubling them. This can have dramatic effects on the earth above. Here we can see how two plates begin to shift apart from one another: [![enter image description here](https://i.stack.imgur.com/QoLBw.jpg)](https://i.stack.imgur.com/QoLBw.jpg) When this happens, the crust cracks open and a chasm is formed. Should this happen in an inland area, the result be something akin to the Great Rift Valley in Africa. When it happens under the ocean, it's like the Mid-Atlantic Rift. But when it happens in a zone of land near the sea, the resulting inflow of water into the chasm results in the sudden evolution of a bay or narrow strait. Below we can see that the fissure has opened up wide and several deformational factors have caused the surrounding land to sink somewhat. [![enter image description here](https://i.stack.imgur.com/iq1fP.jpg)](https://i.stack.imgur.com/iq1fP.jpg) This results in catastrophic erosion of mountains or hill country and an increase in localised volcanism. The continent splitting rift, opening as it does into the distant ocean, now fills with water. Deep down, an emergency scaffold has been placed upon a mantle plume to support the cooling plug that underlies the new Strait. Also, the underlying forces are Not Amused by the abuse to their senses, and may remain agitated for some time to come, as evidenced by residual volcanism, poisonous outgassing and etc. But at least the warring tribes are now safely separated for several generations until they can invent boats or bridges or long range catapults! [![enter image description here](https://i.stack.imgur.com/CavER.jpg)](https://i.stack.imgur.com/CavER.jpg) [Answer] ## A meteor strike. [![enter image description here](https://i.stack.imgur.com/6Ahk8.jpg)](https://i.stack.imgur.com/6Ahk8.jpg) > > Meteor Crater formed in a fraction of a second as 175 million tons of > limestone and bedrock were uplifted, forming the mile-wide crater rim > in the formerly flat terrain. The meteorite was only 150 ft. wide. For > a sense of scale, if this hit Kansas City, the blast radius would take > out the entire city. ([ref](https://commons.wikimedia.org/wiki/File:Meteor_Crater_(crop-tight).jpg)) > > > Now, in this example, Barringer Meteor Crater in Arizona USA, the crater is not quite a mile wide (0.737 miles, 1.186 km), so it's very easy to traverse. But not at first. Imagine this happens in an area with forests or other vegetation that catches on fire. Imagine that settlements in the middle of this large community were wiped out in an instant. And remember that the blast radius here is huge. > > Using scaling relationships determined from nuclear explosions, the > radial extent of the air blast produced by the Meteor Crater impact > event is estimated. The wind velocity at a distance of 5 crater radii > (3 km) from the point of impact should have exceeded 2000 km/h. > Hurricane force winds would have existed as far away as 20 to 40 km, > depending on the exact explosive energy of the impact event. To > determine how this event may have affected the environment surrounding > the crater, the topography, vegetation, and animal life that existed > at the time of the impact are reconstructed. For example, if the > coniferous woodlands were 100 m lower than they are presently and they > had moved farther out onto the plains, then the air blast would have > flattened trees within a 16 to 22 km radius of the point of impact and > damaged them over an area of 4100 to 8500 km2. The distance over which > the damage occurred may have been up to 2× larger in some directions > around the crater because of additional effects produced by the > ballistic shock wave. ([ref](https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1945-5100.1997.tb01297.x)) > > > So sure, it's a simple trip now, but a blast that flattens trees up to 22 kilometers (13.5 miles) away, would easily be enough to separate a community for generations. The stories they must have! And the fear of going anywhere near it. How could they know it wouldn't happen again? Maybe they'd know the impact came from the sky (if it was during the day and if the stories remember that bit), maybe not. Were the Gods angry at them for building villages in that location? Or is there some evil lurking under the surface ready to destroy any fools who venture too near? If the cultures on either side of this were already at war, I think this would seal the deal. War over. Okay, let's go that way from now on. If you want water separating them, a meteor crater could could land in such a way to turn a passible river into an impassible one. Or at least one that's more trouble than it's worth. In 10-20 years when the trees have grown back and people get curious, the river could have swelled. But you don't really need a water barrier to have a psychological one. Who wants to go near that place again? Add in some geographical features like a mountain range or a waterless desert if you want to make going around even harder. Set it up however you wish. Creating a storyline with a natural phenomenon dividing people in less than a week, lasting for generations, is quite doable. With the right geography, politics, technological level, and so forth, it's very reasonable. [Answer] Megaflood from melting ice dam. When glaciers melt, huge amounts of water can pile up behind ice dams. When those dams give way the water comes out. Fast. Supposedly the Hudson River valley was carved in a couple of weeks. I am glad I was not there at the time. <https://io9.gizmodo.com/ancient-flood-myths-may-have-a-basis-in-geological-hist-5940112> > > There is now compelling evidence for many gigantic ancient floods > where glacial ice dams failed time and again: At the end of the last > glaciation, some 10,000 years ago, giant ice-dammed lakes in Eurasia > and North America repeatedly produced huge floods. In Siberia, rivers > spilled over drainage divides and changed their courses. England's > fate as an island was sealed by erosion from glacial floods that > carved the English Channel. These were not global deluges as described > in the Genesis story of Noah, but were more focused catastrophic > floods taking place throughout the world. They likely inspired stories > like Noah's in many cultures, passed down through generations. > > > Your continent had such a flood. A huge amount of water rushed thru low points, wearing them away. Once it was done, the land may have been eroded low enough for the ocean to come up a fair ways along the course of the flood. What was one landmass has become two. Yeah, I took my own answer from here [How might a naturally-occuring geographical barrier between two areas \suddenly\ become permeable so that a few people can cross it?](https://worldbuilding.stackexchange.com/questions/134875/how-might-a-naturally-occuring-geographical-barrier-between-two-areas-suddenly/134876#134876) But the questions are not really duplicates I don't think. [Answer] With a long, deep valley I think it's entirely possible for erosion to gradually chip away at one end, until there's the equivalent of a dam breaking, and a river changes course to flood the valley and probably even increasing the size of the rift with debris being swept away and sudden erosion taking out the banks. Depending on geography it could be the ocean flooding in as well, I suppose. You could feasibly end up with something like the Grand Canyon, which could be possible to cross with enough work (bridges, climbing down and rafting over, etc,) but it would take a lot of work and risk, so unless there's something like a major food source on the other side people probably wouldn't bother. Depending on how long it is and where the other end is it will probably still be possible to walk around, but it might take weeks or months, and as with going over that's a big commitment of time and resources. [Answer] In my opinion, it would be impossible for a continent to split apart and the two parts move far enough away to separate two warring tribes, nations, or civilizations within a short time, a time so short that the war would not have ended one way or another long before the separation process was completed. One way to get around that would be to have two separate continents that were connected by a land bridge. There is a chain of islands between them and during a glacial period the islands are all covered with ice sheets but the sea level is so low that enough of the seabed between the islands is both exposed and ice free that a land path winds between the glaciers. The land path might be narrow in some places but wide enough in other places for lush and bountiful lowlands that might be the best lands on the planet at the moment, well worth fighting over. So during a interglacial period seawater flows between the separate islands from one ocean to another and the waters of those oceans mix and tend to have similar temperatures. So the colder ocean stays warm enough to stay ice free and the dark water adsorb more solar heat than ice would, thus keeping that ocean warmer still, and reinforcing the interglacial period. But during a glacial period seawater cannot flow through the land bridge from one ocean to another and the waters of one of those oceans gets colder and colder and it fills up with pack ice, lowering temperatures worldwide and reinforcing the glacial period. During a glacial period the two continents will seem like one continent to land dwellers even if technically the two continents are separated by hundreds or thousands of kilometers or miles. The two different cultures will expand in opposite directions through the land bridge until they meet and fight over control of one or more of the large lush lowlands on the exposed seabed - which of course they don't know is exposed seabed. And possibly both cultures are landlubbers who don't have any experience sailing the seas. Then a vast volcanic eruption or an asteroid impact destroys a narrow section of the land bridge. The after effects might possibly trigger an even stronger glaciation, so that the entire area of the land bridge becomes buried under an ice sheet and impassable for centuries or millennia. Or the after effects might possibly trigger some degree of global warming. Ice sheet may melt and raise sea levels. And with a part of the lowlands devastated and at a lower level, water can now pass through the former land bridge from the warmer ocean to the cooler ocean, raising the water temperature in the cooler ocean and melting ice on and around that ocean, raising sea levels and adsorbing more solar heat to melt more ice and raise sea levels even more, and so on. By the time the after effects are over and people of the two cultures on the two continents begin to return to the devastated lands of the land bridge, the entire land bridge might be flooded by the rising sea levels, and possibly the nearest islands in the island chain will be out of sight of land. Then the two cultures on the two continents will be separated until one of them develops ships and learns how to sail between continents. Another possibility would be the opposite, having two cultures that live on land, but have fishing and seaborne trade as important parts of their economy, so never explore or settle more that a few dozen miles from the ocean. And possibly two different oceans that the two different cultures live on the shores and islands of are separated by two great land masses with only a winding, narrow, strait connecting those oceans. The climate may be bleak and inhospitable at the strait and near it, so nobody settles there to live, but powerful societies might build forts and station fleets there, and supply them with food and water, etc. from elsewhere, to control the vital trade from one ocean to another. So that would explain the war between societies in the two oceans. Then a volcano erupts in the strait and pours out many cubic miles of lava that solidifies and block the entire strait. Then it will be impossible from people from the two oceans to ever meet again, until someone finds another passage between the oceans through even less hospitable land, or another volcanic event blows away the plug in the strait, or one of the cultures begins to explore and travel long distances on land. Or possibly there is an asteroid strike somewhere in the planet, that causes a glaciation, with icecaps forming and sea levels falling. All the port cities will have to move closer to the receding shores as the sea levels drop. And possibly the strait will become dry land as sea levels fall. and if the continental shelf around the strait is flat enough, the exposed land blocking the strait could be hundreds or thousands of kilometers or miles wide. ]
[Question] [ Closed. This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 1 year ago. The community reviewed whether to reopen this question 9 months ago and left it closed: > > Original close reason(s) were not resolved > > > [Improve this question](/posts/239141/edit) In the not-so-distant future, a corporation announces their plan to turn a colony on Mars into a competition-reality show. This is a believable claim, because others have already colonized Mars, but they are all small groups of astronauts sent on research missions. This is the first private venture to put ordinary people on Mars, and it will supposedly be funded by revenue from the show. However, the makers of the show never intend to send their colonists to Mars. Instead, they take them to a Mars-like habitat on Earth, where they film them and then edit the footage so it appears to be taking place on Mars. They send an empty rocket ship into space, which is aired on TV. They are pocketing the money from the show. So here are my questions: 1. How could the colonists be tricked into thinking they traveled to Mars? The journey takes about 9 months. Will they be frozen for this entire duration? Or will they be taken to the set straight away, under the impression they have been in cryo for 9 months? If the latter, they could begin filming immediately, but there would need to be a lag of 9 months before the public sees the footage. How could the producers explain this time lag to the colonists? Either way, how are they transported across Earth without raising the suspicions of the public? Won’t the colonists wonder why they didn’t awaken on a ship? 2. How could the colonists be tricked into thinking they are on Mars? The habitat is the HI-SEAS simulated Mars habitat on a Hawaiian volcano. The area is isolated and the terrain resembles Mars, but several factors still need to be accounted for. First, the sand/sky would not have the reddish tinge Mars is famous for. Is it plausible to have the colonists wear red-tinted space helmets when they are outside? Any windows would also be tinted red. This would be obvious but because it’s also a TV show, colonists and viewers could be convinced it’s for effect. Second, the day is shorter on Earth than on Mars. How could the colonists be unaware that sunrise/sunset are not as expected? Could strict curfews and blackout shades do the job? Any other suggestions? Third, the temperature will be significantly warmer on Earth than on Mars. The spacesuits will prevent the colonists from feeling the heat, but is it plausible that the thermometers have been altered to read a lower temperature? Lastly, how could a weaker gravity be simulated? I’m sure there are other issues I missed. Overall, how can colonists be convinced they are on Mars, and are my explanations for Earth/Mars phenomena plausible? Have I overlooked anything? Note that over the course of the story, the colonists will slowly discover that something is awry, so it’s okay if the set is not foolproof. [Answer] # Things you’ve missed There’s no way to fake this for an educated audience - the only people you could possibly fool will be the performers. Even then, you’ll have some major problems, especially if the crew is ever allowed outside (and since you mention the sky, I assume they are) ### Atmosphere: Earth has one, with various giveaway side effects * tangible wind * Clouds * Air resistance when dropping objects or moving * Fog * Literally all weather phenomena ## Life: Mars is notoriously absent of life. Hawaiian islands are not. * Birds fly by * insects live in the ground * Primates in rudimentary flying machines pass overhead * Plants. Plant life persists at up to 21,000 feet, so the 8200 of HI SEAS will be rife with it. * Plants 2. Their view will have plenty of plant life at lower elevations. ## Other: * Earth’s moon overhead will be a dead giveaway * There’s really no practical way to imitate gravity [Answer] Choose your colonists wisely As some commentators already noticed, difference between Earth and Mars gravity should be a dead giveaway for this attempted ruse. Other factors like sky which must be very different, air pressure and nighttime temperatures which must be much lower would leave virtually no room for tricking anyone on Earth who spend minimum effort on researching Mars. What do you do? You select your candidates very carefully. They should only be vaguely aware of all of those differences, and during their training, you do not let them know what to expect of the real Mars. Thus, when arriving at the martian base (actually located in some earthly desert) they could be led to believe that this is the actual Mars. They should go out of this base only in spacesuits and for a short time, believing that they can't breath the air outside. In case if someone gets suspicious about the gravity, it can be explained away by this idea that human bodies are becoming weaker in space, so you feel just normal on Mars and can't pull any of John Carter's tricks. [Answer] You've suggested two ways the time lag for travel could be covered -- delaying broadcast nine months has the advantage that you have time to CG things if needed to keep up the illusion and makes it easy to insert the extra half hour plus per day to keep "Sols" the correct amount out of sync with Earth days. "Colonists" not waking on the ship would be covered by having the "cryopods" designed to be opened after landing -- "so the lander only needs life support for the pilots" or similar excuse. Red tints on visors etc. could also be done with VFX technology, with the colonists told their "acclimation drugs" alter their color perception so the habitat lighting, adjusted to match Mars color palette, and the outside light will look white. The things you cannot convincingly fake with anything close to today's technology are gravity and atmosphere. The gravity at the habitat, inside and out, will be roughly 2.5 times what it would be on Mars, and telling the "colonists" they've "lost that much muscle tone in cryosleep" won't change the fact that stuff falls too fast. And the atmosphere outside is breathable (though someone from sea level conditions will be uncomfortable immediately -- ear pain and shortness of breath, possibly lightheadedness, especially if exerting) -- a "space suit" breach won't lead to death in minutes; instead they'd survive for any reasonable time frame breathing the outside air -- there might even be plants growing in locations visible from the habitat or EVA paths. The elevation of the HI-SEAS Mars simulation hab isn't so high that, for instance, rocks have no lichen growth (nor even is that of the Mauna Loa Observatory at half again the height). So, while this kind of "Earth for Mars" setup might be good enough for a controlled and post-produced drama, there is no way it could maintain a long term secret. Likely the first time someone tossed something into the air, or something or someone fell on camera, the jig would be up. Unless the video is being shown only to people with very poor or no science education... And then there's the fact that that habitat has been on TV and some of the colonists (who are presumably at least a little interested in space, else they wouldn't be there) might recognize stuff they've seen before. "We copied all this stuff from that old NASA experiment to save time and money" is a pretty thin excuse along with all the other stuff... [Answer] Be the camouflage for an Actual Mission to Mars whose purposes need to be kept Secret. You're not going to fool anyone with a fake mission to Mars. People will come to watch your launch. Launches, actually, you're going to need to throw a log of equipment to Mars to keep humans alive, and you're unlikely to be able to do that on a single launch. So you'll need lots of different moving parts, regulatory agencies, space agencies, governmental and industrial support, and sponsorships. Even after multiple short-term colonization, there's going to be enough people in the chain that the kayfabe is practically guaranteed to break if you don't actually send a Mars Mission. So send one. Cooperate with a sufficiently secretive but well-funded Nation State who has some plot-required Secret Reason to put boots on Mars, but absolutely doesn't want people knowing what their people are doing on Mars. So there will be a Mars Base to be observed by other nations and space agencies, and there will be matching surface operations and EVAs that are explained by your recruited rubes so that nobody looks too closely. And it's Mars, so presumably the chosen landing location cannot be reached overland on a whim by the people already there. The kayfabe is likely to still break. But by then , the Nation-State's will presumably have retrieved/assembled/conquered/had their crew be slain by whatever they actually went to Mars to do, and the rest of the World probably has something more important to grab their attention than potential lawsuits from your recruits. [Answer] Have a look at [Space Cadets](https://en.wikipedia.org/wiki/Space_Cadets_(TV_series)) They were able to convince the selected cadets that they were on the Space Shuttle, even though it had gravity. You could fool people to say they were on Mars, particularly if you pick the right people, but I do not think this would make a good Science Fiction story. How long does the plot need before they find out? Is it months or years? I can probably get you two weeks... They travel in 'suspended animation'. They wake up slowly in a crowded capsule that has already landed after 'their 'nine month journey'. They have a long list of things to do to unpack and assemble their habitat. They are told they will be weakened by having no gravity for 9 months. Mars has one-third gravity but it will feel like full earth gravity to start with (thanks [Alexander](https://worldbuilding.stackexchange.com/users/32451/alexander) for that). The day is very similar to that on Earth. They keep 'Earth-like' hours. Their stay starts when the moon is waxing, so it appears at night when they are asleep. They start off bring tightly packed in their capsule. It is not easy to see that things are falling more slowly if they cannot stand back and have a look. Most of the capsule should be rigged for zero-G so everything has a place, and things should not fall. The floor should be padded, so if anything was dropped, it would not fall with an obvious 'thump' that might get them thinking. If they were high up somewhere, the sky out of the window would link unfamiliar, if not exactly like Mars. They should have filters in the windows. They would probably not notice the actual difference in light level, but the size of the sun would be a giveaway. Maybe the capsule could have 'fish-eye' lenses, for 'all-round seeing', so they do not see the true angular size of anything. That might give you two weeks, with some people arguing that things were falling slowly, and other saying they were not, until the moon rises. [Answer] I have a bit of a frame challenge, because you're not thinking like a TV producer. #### Plot twist: reality TV is staged. The basic premise is fairly simple to set up. [You wake up in a room](https://tvtropes.org/pmwiki/pmwiki.php/Main/YouWakeUpInARoom). This is an old trope, but there's no reason it can't work. You "sedate" the contestants, and then they wake up, an indiscriminate amount of time later, somewhere else. You say they're on Mars. Put them in a locked habitat, inside a sound stage with a convincing backdrop. Why should anybody doubt you? The audience? Oh but the audience knows, that's part of the draw: watch 12 idiots tricked into thinking they're on Mars when in reality they're somewhere on a stage in the Greater Los Angeles Area. The gravity? Oh, their body adapted while they were sedated, that's why they don't feel the difference. Nobody knows what Mars gravity is supposed to feel like, and who's going to run experiments to calculate $g$ anyways? It's all shot on a sound stage obviously, maybe even an [on-set virtual production](https://en.wikipedia.org/wiki/On-set_virtual_production) stages. That way you can have a complex simulation of the outside that works from a fixed viewport or two. Nobody's going outside anyways. The airlock is sealed, they have no suits, whatever you need to keep them inside. You wouldn't get good footage out of it anyways. Use story editing to craft the narrative that these are clueless colonists trapped on Mars, and then reveal to them it was all a trick at the end. Reality TV may not be scripted, but it's edited. If you film people long enough, you'll get footage that you can take out-of-content to tell any story you want. You decide when they start getting suspicious, if at all, through clever editing and a good voice over. Nobody is going to question the time between production and broadcast. That's just TV baby. That way you don't have to worry about something unavoidable contradicting the story so far, or you can quickly throw in a cooking show to fill the timeslot if someone actually dies for real. Remember, Survivor isn't live, although you could certainly edit it that way. And obviously, pick your contestants. The best decision you can make is to pick professional contestants. The kind of people who make a career out of appearing in reality TV shows, who know which part of their character to amplify to please producers and advertisers. They could even be in on the fact they're not on Mars, and they'll play along because they know it's in their best interests. In fact, you'll probably get the best material if they're in on it. They're professionals after all. #### Who are you tricking anyways? The only people you have to trick is your audience. Not the audience of the show in the story, your audience, the actual people reading the story. See, much like reality TV, your story is edited, with a narrator, telling things nobody can verify. What a twist that the narrator was lying to you all along. [Answer] Your participants are hypnotized. [![hypmopized](https://i.stack.imgur.com/QXpp1.jpg)](https://i.stack.imgur.com/QXpp1.jpg) [source](https://www.bodylanguagesuccess.com/2016/01/nonverbal-communication-analysis-no_2.html) They think they are on Mars. Really they are in Hawaii. But they are totally hypnotized and so Mars takes place in Hawaii. The audience figures it out 10 minutes into the show. It is a very funny show. The corporation was originally going to try to fake people out but the production crew kept cracking up at how silly it is. The company realizes they have come up with something good and they roll with it. The cast comes out of their hypnosis at the end. They are very embarrassed but they are also very famous. Many of the same cast go to "Saturn" in season 2. [Answer] With a little handwaving on the exact technology used, I think you can solve a number of the listed problems. You need to create your own habitat rather than use an existing one and encase it in a giant dome. 1. No plants or animals - during construction, you burn away any existing plants & remove all insects, birds & animals from the dome 2. Red tint - you can project your "sunlight" from the top of the dome in whatever shade you want. 3. No wind, clouds or atmospheric disturbances - no wind inside the dome and you can project whatever skyscape you want, including accurate Mars stellar maps at night and two moons that rise and set 4. Adjust the length of the day - by extending the time between your night & day cycles you can get an accurate Mars-day 5. Atmosphere - you could change the mixture of air in the dome (outside the living habitats) to reduce the amount of oxygen available. Any colonist who gets a tear in their suit would get immediate effects. (see note) 6. In fact, you could slightly adjust the oxygen within the habitat & the suits, and that would make any action feel like it is harder. It wouldn't directly simulate the effect of higher gravity but if people get tired quicker from doing simple tasks, you could probably convince them that was the cause.(see note) 7. Temperature - keep the atmosphere in the dome colder and the colonists will notice some difference between being in the habitat & being outside in the suit. Or you can simply rig the spacesuits to slowly lower their own temperature when worn/sealed. The biggest problems I see with this are the quality of the projection for the "outside" and stopping the colonists from getting too close to the walls of the dome, where they will probably notice issues long before they actually touch them. However, if you make the "windows" on the habitat and the helmets of the spacesuits appear pitted, scratched & blurred the colonists are less likely to notice any projection issues. And you can tether the spacesuits to the habitat in some way so the colonists cannot go too far from the center of the dome. \Note - messing with atmosphere might not be ethical, but given the premise of totally fooling the colonists, I'm not sure this will worry your production company too much. [Answer] The difference in the length of a day would be easy to work around. Just give them rigged clocks that make it look like a longer day. And of course replace any watches or other time-keeping devices that colonists bring with similarly rigged devices. The atmosphere would be only a minor problem. You tell them it's not breathable, so no one tries to go outside without a space suit on. Then how would they know that they don't really need the spacesuits? You say they eventually figure it out. Okay, a big clue could be when someone gets a tear in his spacesuit or breaks the face of his helmet and he doesn't die, but finds he can breathe the "Martian" air quite easily. If you tell them that they're in cryo sleep or some such for the trip, then there wouldn't have to be any great mystery for the arrival on "Mars". Just mock up a fake spaceship for them to wake up in and put it in your simulated Mars. You can tow it there in a truck, it won't matter if everybody is unconscious until after the "landing". Fooling the audience should be easier than fooling the participants, as you can edit up any footage with CGI or whatever to cover up flaws. Hiding moving the subject around on Earth wouldn't be that big a deal. Yeah, you don't load them all on a bus with "Fake Mars Trip" painted in big letters on the side. But if you move them in vans with "Joe's Plumbing Service" painted on the side, who's going to notice? Maybe some intrepid reporter would get a tip about the fake and track it down. That all depends on how well you keep a secret. On the minus side, a lot of people would have to be in on the secret, and that makes it more likely that somebody would give it away, accidentally or deliberately. Other things would be tougher. I doubt the difference in sky color could be solved by simply tinting spacesuit visors. Wouldn't someone who picks up a helmet inside notice that the visor is tinted? They'd have to put on the helmet in the airlock. Wouldn't they notice that the color of everything in the airlock changes? Maybe, possibly, you could have some technologically more sophisticated visor that changes color only when they look outside. Working out the details of how that would work would be tricky, but maybe doable. What happens if when they go outside they see plants? Or see birds flying overhead? That would be a quick giveaway. Maybe you could have a team go through and exterminate all the plants and insects before the "mission" begins. But how could you prevent birds from flying over? Or maybe even some larger animal wandering into "Mars"? Maybe they'd notice that air resistance when they drop or throw something is much greater than it should be. Would the average person notice that or think about it? Likewise, would they notice that things blow in the wind in a way that wouldn't happen on Mars? The difference in gravity would, I think, be the toughest thing to fake. Even if the people in the game aren't physicists, if they have any clue that Mars gravity is dramatically lower, you'd think they'd notice that gravity in their habitat is Earth normal. A sufficiently smart person might measure the speed at which things fall and prove it. But even someone of somewhat below average intelligence should find himself saying, "Hey, I thought the gravity here was supposed to be less. But it seems normal." Oh, I would suggest NOT using an existing simulated Mars habitat. Find some other location and build your own. If you use an existing one, there's the possibility that one of the subjects will recognize it. And it's virtually certain that some number of viewers of the program will recognize it. Plus, habitats used in experiments are not designed to fool the participants into thinking they're really on Mars, but to reproduce conditions well enough to be a useful experiment. They don't try to fake the sky or ground color, etc. You might be able to get away with more mistakes if the subjects are carefully chosen for NOT being particularly scientifically literate or savvy. Would anyone wonder, "Why did they choose all dumb people?" I'd guess not. Most people think they're pretty smart. "I may not have dem book learnun, but I's is pretty clever." [Answer] Make your story a comedy.* That way, it's just funny when your colonists fail to notice all the little discrepancies (atmosphere, sky, plant and animal life, planes flying overhead), and the audience doesn't go "wait, they should have noticed--". The colonists' space suits can be attached to wires when they go outside so they fall more slowly, even as dropped objects fall at the normal speed. [Answer] Lots of answers have focused on red tinted visors for space suits. That makes a landscape without ANY living things look right, but doesn't help much for clouds, aircraft, etc. I would submit that virtual reality technology could be used to edit out these unwanted features from your marsnauts' visors and habitat windows. Visors and windows against hostile and/or low pressure environments can be expensive. So if you feel like display technology can never be high enough resolution to fool reality, then your "corporation" can be being too cheap to have real visors and use video screens instead. Or the graphical indicators overlaid on VR background are so busy that user is distracted from noticing that the background is not real. For simulating launch, you can probably get away with just tilting and shaking the room. Room is tilted up and shaken to simulate pulling g's during launch. And then vibration reduces and tilts forward to simulate gravity slipping away. You'll have to knock out yours marsnauts before reaching orbit because you won't be able to fake true weightlessness unless you put them on an airplane and fly in [zero g parabolic arcs](https://www.nasa.gov/missions/research/kc135.html). Even then you only get 20 to 25 sec of free fall. If there are already marsnauts in your fake habitat, they can help make the illusion stronger by being around to explain things and reinforce the narrative. [Answer] Frederick Pohl used this idea in Mars by Moonlight, Galaxy Science Fiction 1958, which is set in a penal colony on Mars. There is no need for guards, since there's no way to escape, and the convicts have had their memories of the crime erased. Only none of this is real: the "convicts" can't remember their crimes because, in reality, they didn't commit them; they are somewhere in a desert in the US; and they have been carefully selected to make sure that they know nothing about Mars (e.g. how many moons there are supposed to be, whether the atmosphere is breathable, etc); that was easier in 1958 than in 2022. I suggest that you read the story before going further. ]
[Question] [ I have magical insect repellent that prevents nuisance1,2 insects from landing on me, biting/stinging me, or congregating within, say, 1m of my face. Would I still want to employ insect screening on areas that are always air-open to the outside? If so, why? For example, why would I want to screen in a porch, deck or swimming pool? (Screens between indoor and outdoor spaces still have the obvious use of reducing ingress into my living area, so I'm not asking about those. If it makes a difference, assume my insects are similar to those in the mountains of California.) Let's assume I am not also trying to keep certain insects in. (That is, I am not, for example, building an open-air butterfly conservatory.) (1 Particularly flies, mosquitos, gnats, ticks, etc.) (2 "Non-nuisance" insects are unaffected. Butterflies, certainly, probably dragonflies, possibly moths and/or tarantulas, maybe others. It's magic, so it might even be able to change behavior based on the individual or even their mood.) --- Edit 1: The intent was not to get too hung up on how the magic works, just to assume that it does, but since some folks are answering based on assumptions as to how it works, perhaps I should clarify... The magic is wearable (i.e. affects a person/animal, not an area), extremely persistent (lasts for years), it's inexpensive enough that most middle-class people wouldn't think twice about using it on pets, and one can assume that guests will "bring their own". For most purposes, and particularly from a practicality standpoint, you could substitute a really effective, inexpensive science-based rub-on/spray-on repellent. --- Edit 2: I intentionally left out details in the original question, because I like seeing generally applicable answers (that's the purpose of this site, after all!). So, please don't take this as invalidating any existing answers; after all, my specific answer might be "because screening in porches is just what people do". That said... this specific porch is a small part of a much larger deck; far too large to screen in the whole thing (most of which is anyway open to the sky). The main eating areas are in the open-to-sky areas; eating in the screened-in part would be intimate and inconvenient (it's on the opposite side of the house from the kitchen). The screened section is the only part with a normal-height roof, and is also facing a mountain slope at fairly short distance, so "shade" isn't an issue. Any answers that address this specific situation would be awesome, however, looking at it more closely, I realize there are a number of aspects of this porch that aren't exactly practical, so for my specific case I'm leaning rather heavily toward "because it's expected" as the reason. Thus, unless I happen to get a particularly brilliant answer for my specific case, I will accept one for why this world would generally bother to screen things, so keep those coming also! --- Postmortem: Lots of good answers, often with recurring themes; thanks! In the end I awarded [Ash](/a/201878/43697) (largely for having the longest list of reasons), although [Mike Serfas](/a/201882/43697) definitely gets an honorable mention, and I want to give a shout-out to [Radovan Garab√≠k](/a/201877/43697) for the mention of keeping bugs (and birds, squirrels, etc.) out of your swimming pool. Ultimately, for my specific instance, I'm going with a combination of "tradition" and keeping crud out. There's a huge area of deck, but more than half is open to the sky and can take advantage of rain to do some "natural washing". The part that's screened is fairly enclosed even without screening, and is much more "intimate" than the other areas; keeping insects entirely out because someone might want to take a nap there is plausible, though perhaps an accidental benefit. I got myself into this mess, after all, by giving my setting a screened-in porch without stopping to ask why I was screening in that, and only that, specific area. Given plenty of reason why my story-world would in general still screen in outdoor areas, I see no problem making that the in-universe explanation as well üòÑ. [Answer] ### Protect against Ember Attack This is the number one cause of house loss in Australian Bushfires - tiny smouldering bits of vegetation riding on the wind advancing up to 15km in front of a bushfire. Even city / suburban homes 10km+ from the bush are at risk. I suspect the insect screens available in Australian hardware stores are different from other parts of the world because of this - they're categorised based on fire protection first, dimensions second, and the top end ones are made from aluminium. But "To stop my house burning down" is fairly high on the list. ### Minimises cleaning: So I like a little bit of fresh air but not full outdoors, insect screens also filter a bit of the dust. They get very dirty from dust (and real estate agents conducting inspections love telling you off for not cleaning them). The dust they catch is dust that doesn't blow into your outdoor area (and thus also house) and settle in hard to clean places. ### Minor pollen filter: They don't filter all pollen, pollen is tiny, but screens do catch some. I have pretty bad year round hayfever and the difference between a full open door and open-glass-but-screen-still-shut is notable. "Must take anti-histimine in minutes or nose will run" vs "Must take in next few hours". Surrounding my outdoor entertaining area with these screens will reduce my dependence on anti-histamines, as less pollen gets up my nose. ### Flies are filthy. You don't want flies in your food prep area - if they've recently touched poo, you don't want them walking over your clean dishes or fruit bowl. (Yes, outdoor kitchens are a thing.) This is also true of BBQ and outdoor grills. ### Vet bills are expensive. The insects are avoiding you - but are they avoiding your furry friends? A mosquito bite, ticks, fleas, etc can harm you pet, and thus your wallet. ### An infestation that stays 1m from your face is still a problem. A wasps nest in your walls is going to cause a problem even if they don't approach you. If for no other reason that it freaks out guests and you're sick of picking up dead wasps. ### Stops birds nesting in the rafters Birds like to nest on the rafters under verandas in outdoor areas. This results in things falling that you don't want to step in - from bird poo to shattered eggs to nest bits. ### Don't share your food with birds / bugs Outdoor dining is a thing. So is getting distracted from your dinner. When that happens, bugs and birds can take a swoop at your food. ### Must be there by by-law / tenancy code. Your guy with the magic spell doesn't care about them, but his landlord sure does. Other people have lived in the house before him, and will live in it since, and they need protection. There can be zoning laws requiring these. I know a building I once owned a tiny apartment in there was a requirement for the screen panels to not be taken out of the balcony window except for brief cleaning. If you looked at the high rise from the ground and a few panels were missing it looked ugly. There can also be safety laws requiring these. Australian Bushfire example again - in the high fire danger properties (basically all that aren't farms or suburbs really), you need screens in dozens of places, that auto-shut (can't be left open), and must be made of aluminium or fibreglass. It's to stop the ember attack threat. ### Decent quality ones can act as a privacy screen Insect screens also block a decent chunk of light. We have dog-proof ones and live in a medium bushfire risk suburb and they block about 50% of the light - with the lights off on one side, you can't see through them. While skinny-dips in the pool are rare, keeping the insect screens up certainly makes it difficult for the creepy neighbour with a telescope on his roof to spy on you. ### They're also a bit of shade Every bit of sunlight you block can keep your entertaining area a bit cooler. Insect screens do vary in shade capability but they're better than nothing. ### Noise. A mozzie is very loud, even at 1m away. They will probably spend the night doing laps of you, and it will sound like trying to sleep through sirens. ### Your magic spell wouldn't have stopped any of my bee stings I've been stung twice by a bee in my life. Once on my bare foot after stepping on one accidentally, and once on my leg after resting on grass which included a dead bee, stinger pointing up. A magic field wouldn't of protected me from either. An insect screen would have. [Answer] ## Non-insects. I'm going to assume that this magic repellent can be sprayed all around the house so noise, dead insects etc. are not a problem. It genuinely keeps insects out. However... Birds. Birds are cute, friendly visitors. People like them. They dote over them when they make it into a big box store and shop beside you. But birds do have a way of reminding you of their presence after they have gone! There's statuary in that enclosed space of yours, and the magic cleaning robot has been banned from working on it ever since the unfortunate patina incident. (But that statue was dirty, it still protests...) Bats. Mostly the same reason, with a double helping of viral paranoia. Spy drones. Futuristic magic technology (no wait, present technology) meets the same puerile reasons for spying as always, and occasionally, something far more sinister. Leaves. If you invent yourself a leaf repellent, you'll have a winner in the marketplace. A repellent for neighbors with blowing machines that make 10,000 times the noise that would be inherent from a simple jet of air would be even more highly prized. (You can make it a pesticide instead if you want) For now, however, fly screens at least keep leaves out of indoor outdoor spaces. [Answer] Screens discourage witches. [Etruscan Roman Remains in Popular Tradition](https://books.google.com/books?id=zaFJAAAAMAAJ&pg=PA172&lpg=PA172&dq=witches+count+holes+sieve&source=bl&ots=ab_-3ZlNWI&sig=ACfU3U2hjxy579p9GDqIV4eTyN2zKD5WbQ&hl=en&sa=X&ved=2ahUKEwj0ueevlqvwAhVOZc0KHWRRAeoQ6AEwB3oECAgQAw#v=onepage&q=witches%20count%20holes%20sieve&f=false) > > When a man is visited in sleep by witches who ride or torment him, you > should fasten in the chimney a coarse linen cloth or a sieve; tie at > the head of the bed a pair of woold cords or a branch of fern leaves, > in which the seeds are almost ripe; sprinkle a cup of mustard seed on > the door-sill. The witch must count the intersitces of the cloth or > sieve, the seeds of the fern or the teeth of the cords, and must pick > up every mustard seed, counting as she does so, ere she is free to > torment the sleepers by knotting their feathers, riding on their > breasts, or whispering to them awful dreams. > > > When a witch encounters a collection of small things, she is compelled to count them. It seems like this is not random natural small things but small things placed through human agency. Although this source title mentions the Etruscans this is probably witchcraft lore originating in Africa and so prevalent in the American South. Window screens are pretty much insurmountable to compulsively counting witches and might account for why there is a lot less witch trouble in the US since the early 20th century. [Answer] ## For the sake of the insects Suppose you are allergic to bees, and don't want to be stung by one. You might cast the spell to protect yourself. But that doesn't make you anti-bee. Bees pollinate flowers. Bees feed birds. You want bees to thrive, just not near you. Any queen bee that makes a hive near your bedroom while you are at work is going to be inconvenienced or killed when you come home, and the hive is demolished by the spell. Better to put up screens to avoid the queen bee coming too close in the first place. [Answer] Sound. A fly bashing against a window is distracting. Mosquito buzzing can keep me awake from the other end of the room without ever stinging me. It's for peace of mind. Cleaning. Having to clean up dead flies and other insects from your window area's is also an annoying business. Hygiene. You won't be close to your food all the time. Worst I've found was a wasp that got into my food as I was cooking, cooked partially chopped up wasp is unpleasant to discover, and many insects you won't even notice their presence in your food until you bite down (if your food tastes funny for one or two bites you probably ate one). Also having insects relieve themselves on your food or leave pieces of their previous food on yours isn't a pleasant idea. [Answer] Swimming pool - you do not want dead ex-insect bodies in your face when doing your daily relaxing swim, I guess... And a mosquito buzz alone can wake you from further than 1 meter distance (source: personal experience), so you prefer to keep the screen on your windows... [Answer] A magical spell is active: it requires energy, or attention, or concentration, or some such. Screens are passive: they work by making it too difficult for insects to get through (i.e., the insects would have to expend energy breaking past). Think of it the same way you would if someone invented some electronic device that (somehow) repelled insects using (say) magnetic fields. All's well and good until the power bill comes or the dog pulls the plug out of the socket. Then you'd be wishing you'd just put up a screen... [Answer] ## Guests You don't want to cast it for everyone who walks in, or else they would object to having you cast it. For whatever reason. Time would probably be the simplest. Or it just is considered polite to not show off your magic. ## Expense You have to keep on casting the spell. Screens, it's one and done. ## Other harm Screens keep flies away from the food even when you aren't there. And so on. [Answer] ### Screens are a backup. Spells may fail. They may consume resources you can run out off. They may need regular recasting, but you absolutely need 8 hours of beauty sleep. Or they need regular recasting, but just like your daily pills, you often forget to recast them. They may not work well on toddlers and babies. They fail to be effective when you use the microwave. And your WiFi works a lot better when you drop the spell. ### Secrecy and/or vanity. You don't want your neighbours to know you're casting that spell. Or the IRS. Perhaps there's a tax to be paid on each spell cast, and you really hate to part with you hard earned doubloons. You want to give the impression to don't need this spell. It's only plebs who use this spell, and you'd never admit you use it. You still use it, but the screens give you deniability towards the neighbourhood and the taxman. ### Laziness. You bought the house with the screens. Why bother removing them? And besides, during the holiday season, you can hang decorations from them. [Answer] A cyberwizard approach: a screen would prevent attack from tiny things that aren't bugs. Example: tiny machines escape the magical barrier, because the spell only pushes away living creatures. Another poster mentioned fire embers carried on the wind. Also, you might be able to prevent bugs from annoying you, but what about bird poop? No, seriously-- I've stood under one of the most massive flight of bats in the USA leaving their cave. The bats happily ate all the bugs in the area. However, the bats above me managed to poop on my head. I'm not kidding. The shame! ]
[Question] [ Background:As humans throughout history, [we've been trying to make a time telling device](https://en.wikipedia.org/wiki/History_of_timekeeping_devices "wiki page on history of timekeeping devices"). It makes sense, too, you'd want to know what time to plan and arrive at certain events. With that in mind, let's imagine a society without them. Context: In this society, they're highly against time telling devices (sundials, water clocks, watches, etc.) but still use the day/night cycle to give them an idea of what time it may be. Instead of saying "Arrive here at 3:00," these people would say "Arrive here once the Sun is in the middle of the sky". And secondly, these people, as their society advances more and more, would want people to be on time for specific events; rather than being there within an hour or two of the designated time. Question: Would a society like this be able to enforce people to arrive at certain events with only the Sun in the sky as reference, no way to tell time with a clock or measure the position of the Sun with anything but their eyes? [Answer] I'm going to posit a hard NO on this one. Time telling isn't just about getting somewhere at the same instant, it's actually synonymous with science. There are a lot of things that you can't do without accurate time telling. Update This answer is getting a lot of flack because society did just fine without complex time-telling devices until the 1600's. Time telling is not as critical as mathematics or record keeping. From that perspective, the question should probably be "How advanced could a society get without time-keeping devices?" To my knowledge, the critical need for time keeping was actually in tracking work hours. Realistically, you can't even get away with "you will work until I tell you you're done" with slaves. Earliest case of this was 1300BC. The Greeks and Romans both had legally defined system of seasonal hours. As such, you could say that the history of time-telling is tied to the history of labor negotiations. You also need to ask how tightly you want to define "time keeping." Nothing tighter than hours was used before the 1500's, but there's arguments either way about how useful it would have been if they'd have had it. You also have to ask if calendaring counts as time-keeping in their view. ## Astrogation It's impossible to tell where you are, east-west, without knowing what time it is. Every day, the captain would spot the sun when it rose. He would compare that with the time, and that would tell him his longitude. ## Baking and construction If you can't keep track of how long your cookies are in the oven, you will burn your cookies. There's more to this, though. You need some sense of time to allow cement to properly mix without prematurely setting. The Romans couldn't have built their aqueducts without some kind of clock, or at least an hour glass. This can also be extended to brewing, soaking seeds for germination, etc., etc.. ## Siegecraft This is probably the point that your society will fall. You can't formulate the mathematics of thrown objects without tracking time, so you lose the ability to design quite a lot of simple machinery. Any civilization that tried to enforce this would be readily conquered by a civilization that didn't have such an issue with trebuchets. ## Going around the issue You can guarantee that, if you forbade them from doing so on purpose, they would do so "accidentally." This would involve building their houses in such a way that they could use the edges of it against the terrain to tell what time it was, or just parking their cart so that it would go into shadow at "closing time." [Answer] Oh yes, definitely. We know this because our own civilisation has been able to enforce it. Creating a reliable time-measuring device which is also portable is just very difficult, and was only solved in the 18th century, and of course these accurate clocks did not become affordable to a common man until much later still. Prior to that, clocks were found mostly in central locations in towns and cities, where only a rather small minority of people lived, and the countryside-dwelling majority could indeed only measure the passage of time by observing natural events. And for most purposes, this was enough. If you wanted to announce the beginning of some important activity, like say the Sunday mass, then you would make some noise - ring a big brass bell hanging high up in the church's tower, for instance. Even in the context of industrial revolution, when turning up to work at a specific hour regardless of all other considerations became important, you would have knocker-ups, people waking others up by knocking on their doors or windows. (Often these were night watchmen, who were awake at night anyway, making some additional money on the side.) Now sure the priest and the knocker-up would need some form of time measurement, but here's the thing: they would not necessarily need to know what time it is, but only how much time has passed since some event, natural or man-made, that anyone could observe. In this way they could still accurately measure the passage of time with devices such as hourglasses, and get by without a clock telling them the instantaneous time. Oh and I would expect the occupations involved with measuring time to develop tight-knit guilds, closely guarded trade secrets (it would help them greatly to know exactly how much sooner or later does the Sun set each day compared to the equinox, for instance, which itself would vary depending on how far away from the equator you live), and something of a supernatural aura in the eyes of others. [Answer] This is a [Frame Challenge](https://worldbuilding.meta.stackexchange.com/q/7097/40609) The first timekeeping devices on Earth were via the ancient Egyptians circa 1,500 B.C. That would be the practical limit of your civilization's development. From that point forward, timekeeping for any reason was deemed critical enough to deserve someone putting enough thought into it to develop the sundial. But could it be done? Ignore history. Could it be done? No. Without the development of timekeeping devices, it isn't reasonable for someone to expect to hold an event at a precision time. How would they know to do it? Locally (as in within, say, 100 km of any given event) there are only three times per day (daylight) that can be set with reasonable precision without the aid of timekeeping devices: Sunrise, Sunset, and Noon. Maybe... maybe... it's possible to hold an event at halfway between sunrise and noon, and halfway between noon and sunset... maybe... and meet your expectations. But any event expecting to be more precisely scheduled and attended than that is impossible. Worse, those three times vary by latitude, longitude, and time of the year. The the further in advance you set an event and the further away you expect people to attend, the less likely any of those moments during a day can be plausibly precise. But, to complete my Frame Challenge, what's stopping me from using me as a timekeeping device? Finally, what's stopping me from being my own timekeeping device? What's the difference between a sundial and me, standing still for 30 minutes, and knowing how shadows work during the course of a year in my area? When you say no timekeeping devices... I'm holding you to your word. Your people don't know or don't want to know how to keep precision time in any way shape or form. The second somebody comes up with a clever way of doing it without creating a device, your question's veracity falls apart because what was just invented was a timekeeping procedure, and the only difference between that and a device is the invention of a convenient device so (e.g.) you don't have to stand still for thirty minutes. So, no. Can't be done. * The desire for precision is the desire for timekeeping. You can't have one without, eventually, the other. * Societal development (technologically and culturally) must stagnate (for some reason) without timekeeping devices. * The moment someone figured out how to do it without creating a device, they created a device. The person's ability to observe the heavens with enough accuracy to meet your expectations makes them the device. After that it's just "I'd rather be drinking a beer in the shade talking to my friend while something or someone else does the timekeeping." [Answer] In Northern Brazil, at a certain time of the year, a quick but huge burst of rainfall in the early afternoon is regular enough that people schedule their appointments "after the rain". As a raw idea, there may be visible natural phenomena other than the sun cycle that gives your people a fine sense of time without any devices. [Answer] ## Timekeeping as an occupation Take Computers as an example. Until the Second World War, "Computer" was not a device - it was a job. When there was enough demand for quick and complex calculations, [some people specialized in that](https://en.wikipedia.org/wiki/Computer_(occupation)). Your society will therefore see a rise of professionals, who know the exact time - the Timekeepers. They will use various mental tricks and skills to measure different amounts of time. A mantra, that takes precisely one minute to tell. A walk around the town square, taking precisely half an hour. Things like that. Since timing devices are a taboo, they will need to time their skills with the guidance of other Timekeepers. Expect a guild to form, just like with any other trade. In the beginning, they may simply sit on city squares and tell the precise time for a penny. But when technology advances, more and more precise measurements will be necessary (e.g. for chemistry and metallurgy) and the guild will accumulate a lot of influence. [Answer] No, it's not practical to tell time with such precision without instruments. For starters, if it were, people would probably do that. Two key problems you will run into are angular resolution, and adjusting for axial tilt. Problem 1 is that you need an accurate measurement of where the sun is in the sky. The difference between "on time" and "15 minutes late" is only a few degrees of arc, and it's hard to even look directly at the sun to make your measurements. Humans aren't very good at determining angles without landmarks either, and there's nothing visible in the sky to compare the sun with. Conventionally, you could use a sextant to obtain quite precise measurements but your people aren't allowed. Problem 2 is that if your planet is like Earth, it will have seasons. Both the length of the day and the path that the sun takes through the sky vary, and how much they vary depends on your latitude. Trying to adjust your time measurements off the cuff won't be very accurate, and looking it up in an almanac every time you want to tell time would be impractically inconvenient. Problem 3 is, what happens if it's overcast? Everyone takes the day off? [Answer] If you look at our own history, you find that there was in fact resistance to changing existing time keeping methods - but over time, as society becomes more complex, and especially by the industrial era, it just becomes too important to keep good time. Early on it's just planning out meetings, keeping track of historical events, but think about things like warfare, or further on tracking weather, doing business, etc. Even in the middle ages and earlier, there were some fairly good time keeping devices, and I doubt that the industrial revolution would have been unaffected by a lack of timekeeping devices, especially small convenient ones like pocket watches. So no, I don't think that a sufficiently advanced society could get very large and complex without adopting more rigorous time keeping standards. I'm sure that you could modify the taboo in some way to still make interesting limitations, while not removing a very important tool. That is the crux of this, humanity will make foolish decisions often, where a good resource is rejected - think nuclear power in our day - but if a tool is unbelievably useful, like timekeeping, it is hard to keep a taboo on it. I think it would also be helpful to think a lot about the reason why such a taboo would come about. A related example of your taboo comes to mind in the Stormlight Archive, where gambling with something like dice, or anything involving luck is considered sinful, because you're trying to predict the future. The taboo resides in fears and such about trying to predict randomness, trying to "control" it. All this being said, I like the idea of a taboo centered around time, it probably just needs some refinement. [Answer] The Town Bell So, you've got groups of people who need to meet up for some collective activity at a certain time. But you don't want any mechanical timekeeping device. Here's a solution. You've got a guy with a big bell who decides what time of day it is. He doesn't have a clock and doesn't know the time precisely. But he can tell by the light, or just his gut sense, when it's about mid-morning or noon or mid-afternoon and so forth. So, perhaps six times a day he rings his bell at approximately the right time, and everyone hears it. So, you can schedule a meeting: "meet in the west field after third bell." When people in town hear the third bell, they head to the west field, and arrive at roughly the same time for the meeting, perhaps within about fifteen minutes of the bell ringing, depending on the size of the town. If you want, there's a way to be a bit more accurate about the time than the bell-ringer's "gut feeling," still without using any timekeeping device. The bell-ringer can be a guy who spends his day doing some repetitive job, and he rings the bell based on how much of his job he got done. Perhaps he's the baker. Perhaps he's plowing the fields or laying bricks. He knows roughly how many bricks he can lay in a day, so he divides that by six, and every time he lays that many bricks he rings the bell. Another option would be to have the guy to be a priest who spends his entire day repeating the "prayer of the hours" at a measured pace. After each 573 recitations, he rings the bell. Or he could be a musician playing the lute, again keeping time and ringing the bell after so many songs. [Answer] ## Not very precisely It is, of course, impossible to look at the sun with the naked eye. Consequently, it's hard to tell when it's at the apex without instrumentation. Such as a known thing casting a shadow, generally with marks to indicate the past and future, because a shadow by itself won't tell you unless you know what it means. On the other hand, for millennia civilizations rose and fell without any measure more precise than "hour" which might, actually, be longer than our contemporary hours. "Minutes" were invented in the last millennium, and came into common use after clocks. "Sun is approximately in its highest position" worked fine. (Only pedants note the difference between Solar Mean Time and Solar Apparent Time -- the average time the sun is highest in the sky, so that there are exactly twenty-four hours in a day, and the actual time, which can be as much as fifteen minutes out.) Even hourglasses and sundials could not measure time in the fields, so those working the fields would work by the sun which was good enough for their purposes. There would also be measurements of time that are shorter. These are not instruments but songs or poems. They would possibly be regarded as spells or incantations, but what they really are is time measurement devices. Even in this century -- I know a woman who got a recipe from an older woman, who couldn't tell her how long to cook something on a frying pan, but would describe it as "Two Hail Marys" or "An Our Father and a Glory Be." They may not even realize they are time measurements, themselves. ]
[Question] [ Is there any science-based way that one could explain cars running not on natural gas (autogas) but rather on noble gasses like Neon, Argon and/or Xenon? [Answer] Noble gasses are called "noble" because they don't interact with other elements (same way as nobility of the past didn't mix up with lower classes). Since the entire concept of combustion engine works around chemical reaction, it follows that no combustion engine can work using noble gases, because there would be no way to get energy out of them. However: * you can still run an engine on compressed noble gas rather than compressed air. It will just be more expensive than compressed air. * helium and neon are the only noble gases which can undergo fusion (I haven't found evidence that argon and xenon can undergo fusion), but that requires conditions similar to those found in stellar cores to happen (for neon, it need stars with more than 8 solar masses). [Answer] ## You need a new technology I assume you've chosen noble gasses because they're completely unreactive. The flip side of that is that they would release a lot of energy, if they were somehow in the wrong state to start with. Let's suppose you have a car based on an ultracapacitor - instead of batteries, it stores all its energy in a separation of charges. Now to be sure, what I'm thinking of here straddles the boundary with a liquid-state battery or maybe a Bose-Einstein-state battery; maybe you'd call it that instead. One 'electrode' consists of a cloud of Ne2+ ions - absurdly reactive, just want to be neon again. The other 'electrode' is more prosaic, maybe O- groups attached to a substrate. It can readily shift back and forth between having the oxygens with negative charges on them or being a peroxide. The trick is layering these electrodes right next to each other, without the juicy lone pairs on the oxygen being gobbled up by the desperate neon atoms. Here's where you need some new technology. What if the neon ions are in, I dunno, maybe a Bose-Einstein condensate, with a delocalized state that perpetually orbits the negative charges on the oxygen without ever quite going in. Or maybe you use some kind of infrared/microwave light to keep them from getting too close. Instead the neons are deducted at a far point, taking electrons routed around from the back of the oxygen electrode. This is 90% handwaving, 9% bunkum, and 1% mechanically recovered chemistry meat, but a lot of sci-fi books and shows don't have that much, so there's that. [Answer] <https://en.m.wikipedia.org/wiki/Ion_thruster> Noble gasses used in sattelite engines to correct orbit. Those are low power engines, and only work in vacuum. If your setting is based in space, and there is plenty of energy in mobile sources, then cars (or rather small spaceships) could use noble gasses to run around some space city. Keep in mind, this engine still needs large energy input. Batteries can barely fit, short term only. Noble gasses are used because heavy atoms are required, that also dont stick to themself. Apart from that: no. I dont see any practical usage for transport. Compressed gas storage is very low power density. Cryogenic storage is especially hard with nobble gasses as they need low temperature. Noble gasses arent good for fission or fusion. They are also expensive. [Answer] ## It is possible but very impractical Xenon has over 100 compounds identified that it can form to release low energies. Xenon difluoride for example releases −108 kJ·mol−1 on formation. This is not a lot of heat, but it is heat, and could produce usable work. A usable vehicle would be highly unlikely, but for a lot of fuel, it would move a short distance. There are no known high energy compounds with the noble gasses, as yet. [Answer] Good luck containing the ultra-hot, ultra-dense helium needed for the triple alpha process. You're not going to get chemical energy out of them so you have to go nuclear--and that's the easiest one to do. (Hint: The center of the sun doesn't do it meaningfully.) It's aneutronic and emits only gamma rays so there is no lingering radiation to deal with. You also could have helium-argon and argon-argon fusion, both are likewise free of lingering radiation, but they require even more extreme conditions. Going farther down the table you're not going to find energy until you get into the fission realm. [Answer] I agree with the answer of L.Dutch, however depending on the technology level, you can also consider small scale nuclear fusion. (Probably an overkill though...) [Answer] Further to other answers, it isn't strictly true to say that noble gases don't ever form compounds, although they are famously unreactive and would be unlikely to make a good fuel in their pure form. The heavier noble gases can react with highly reactive species. For example, xenon can be made to react with fluorine to form several fluorides, from xenon difluoride (XeF2) to the hexafluoride (XeF6). The reactions are endothermic, so to get energy out to run a vehicle you'd need to start with the fluoride and break it down. Your exhaust would probably include pure xenon (or whichever noble gas you use) so you might just get away with describing the vehicle as "running on a noble gas". There's a brief discussion [here](https://sturgeonshouse.ipbhost.com/topic/1524-noble-gas-fluorides-as-rocket-fuel/) on the plausibility of using noble gas halides as rocket fuel. The first example produces HF in the exhaust, which would be bad news in a car - HF has some nasty effects on living things. [Answer] Helium (a noble gas) undergoes fusion with oxygen to make Neon (another noble gas). Although this only [happens naturally within a star](https://en.wikipedia.org/wiki/Stellar_nucleosynthesis), I suppose you just need to supply your [Mr. Fusion](https://backtothefuture.fandom.com/wiki/Mr._Fusion) (Back to the Future) with Helium to have a car powered by a noble gas. [Answer] Well, we don't know how the "car" functions. While most answers focus on using a noble gas as a fuel (which leads to nuclear fusion) or as a working gas, there are other options. # Coolant Your (very hand-wavy, I must admit) car engine uses something else as a fuel. It might be a fission reactor, eezo, unobtanium, whatever. The key characteristics of this fuel is that you need so little of it, that no frequent recharging is required. However, the way this engine is built, a more conventional cooling system (based on a radiator that dissipates into the surrounding air) is not sufficient. It is not economic / does not fit the usage model to carry some water tank for evaporation either. Instead the manufacturer of the "car" sells coolant cartridges, filled with a liquified noble gas (say, Helium). You have your gas stations and inkjet cartridges back, now for super-engineered cars, great business success! To elaborate, the actual fuel source is eternal or at least not user-maintainable. But instead of a more sane cooling solution, some cryogenic-level stuff is used to bind the user to the supply chain. The novel engine, the novel isolating material for cryogenic dewars with Helium, all this is rather handwavium. As the whole system is rather over-engineered and makes only commercial sense, at least I hope those "cars" are fast! ]
[Question] [ I, Charlemagne Darwinius, am a great scientist who has devoted his life to the study of the evolution of different species. Priests speak of man being created by a supernatural being called God, who became increasingly angry with them due to their descent into wickedness. To punish man, he sent a great flood to wipe all life from the earth, sparing only a few humans and animals who took shelter in a great ark. For 40 days and nights, the flood drowned all living things on the planet, until the waters receded. The survivors on the ark were able to carry on their existence, and today's humans are the descendants of those survivors. However, as a way to humble humanity, God decreased their lifespans going forward. When once humans would live hundreds of years in good health, now they would be lucky to live a few decades. As they aged, their bodies would grow old and decrepit until dying, as a way to remind humanity of who was really in charge. Recent archeological evidence has revealed that their actually had been a great flood at one point which encompassed the entire world, leading to an extinction level event. Other evidence has emerged which suggests that human civilizations existed before this flood, with numerous empires and cultures inhabiting the earth. This gives credence to the stories told in these parables, which has forced me to update my theories. If the evidence is true, then humans had lived much longer, healthier lives in the past, and were far more able than we are today. For reasons left unexplained, our lifespans had shortened over millennia, to the point where those who get past a century is incredibly rare. This is despite the fact that we are much more technologically advanced than our ancestors, with access to better medicine and care. My phrase "Survival of the fittest" is a way of describing the mechanism of natural selection. The biological concept of fitness is defined as reproductive success. It is best understood as survival of the form that will leave the most copies of itself in successive generations. Shorter lived humans have outcompeted those with longer lifespans, appearing to make us less fit. What explanation could be given for this occurrence? [Answer] There are several benefits to humans living ~80 years compared to living hundreds of years: ## Population Growth If humans die faster, then they need to breed more to compensate. This would lead to an explosion of reproduction and human populations, as where before a human would maybe have one or two kids over the course of 400 years, they are suddenly having 4 or more within the first 40 years of their life. This sudden increase leads to greater amounts of manpower required for many things and helps cement the human status of a global super-apex species. ## Geographical Expansion With so many more humans walking around, it's natural for them to expand their influence at a comparable rate. More people means more settlements, more people exploring unknown territories, and more people to form armies with which to tame either the wild or their neighbors. As a result, where people once confined themselves to small pockets scattered throughout the world, suddenly there are fledgeling kingdoms and civilizations popping up everywhere. After tens of thousands of years of human progress more or less stagnating, it only takes a couple thousand years for entire countries to start springing up like weeds. ## Record Keeping Before, every village would have one or more elders whose job was to retain the knowledge and history of their clan. This knowledge is built up over centuries and is passed to the individual who would become the next elder. However, if humans no longer live as long, that knowledge would get passed more often, and more and more knowledge would get lost in the repeated retellings. As such, humans needed a way to store their knowledge in forms that would be immune to the failings of the mind and the ravages of time, leading to rapid development and widespread use of writing systems. ## Technological Innovation As a consequence of an increase in record keeping, knowledge suddenly becomes a lot more accessible to the general public; no longer needing to receive a sermon from an elder who may take days retelling something and details getting lost or mutated over time, the average person can just go to the local library or record house and read whatever they needed to know. The records can also be duplicated by scribes and taken all over the world, allowing a vast sharing and mingling of different cultural and scientific wisdom. With so many more eyes and minds viewing the same information, technological breakthroughs are guaranteed to happen and at a much faster rate. ## Agriculture More people means more ability to claim and protect land, which means large-scale agriculture finally becomes a feasible option. Before, it was neither necessary nor practical to create farms larger than what would feed half a dozen families, as there simply weren't enough hands to harvest the crops nor eyes to watch for animals, pests, and the inevitable march of nature. But with more people to help manage the farm, you could have farmland that spanned miles of countryside, leading to an abundance of food and overall prosperity. ## Genetics Now that humans are breeding more often, new generations are being created more rapidly. This results in a higher rate of beneficial genetic code getting integrated into the overall gene pool, as well as the rate of potential breakthrough mutations. And once tribes get to the point where they are large enough to start interacting on a grand level, there will be a much larger and more diverse gene pool leading to a more stable and successful place in the biological scale. [Answer] > > Shorter lived humans have outcompeted those with longer lifespans, appearing to make us less fit. What explanation could be given for this occurrence? > > > Shorter lead time of new features and consequent faster adaptation. The math is easy: if a species takes X years to be able to reproduce, no mutation will spread with a pace faster than once every X years. Therefore a species reproducing faster than that will take less time to adapt to a changing environment. That's one of the reason why bacteria develop resistance to antibiotics very quickly. [Answer] Resources Survival of the fittest doesn't mean having the most copies of that species/lifeforms. It is having the most stable way to keep this subset of lifeforms to stay alive. This is important. Humans for example used to get a lot of children. This is a strategy in times with high child mortality. With many children you have more that might make it, as well as a bigger community that can help raising children. Yet when we look at countries that have plenty of food and good medicine, we suddenly stop expanding so rapidly. We devote more resources to a few or even singular children. Despite having enough resources and low mortality, we don't explode into populations that are unsustainable. This is important. Expanding rapidly normally means that resources will get tight. Many species will then meet with rapid decline of the species if resources dwindle, leaving them less strong over time. Although not practiced by all species, expansion in good times is best slowed. Here you can see something interesting as well. In humans we keep our elderly and infirm, even though they might not contribute or be able to reproduce anymore. Yet for many species this isn't a given. If an individual becomes old or weak, it can be more advantageous if it dies. It'll not eat up more resources, allowing for more new children to be raised. Strong new generations that can keep the species alive and stable. A short life span is then ideal. This is practiced by so many species it's hard to keep track. For example, fruit flies could in theory live much longer and reproduce more frequently. Yet they live short bursts of life, dying just as quickly as they started. Leaving a nice niche for the new generations to fill. Even in humans we can see a supposed forced shorter live span. Although not proven, in some Scandinavian tribes it's suggested they practiced Ättestupa, suicide or murder of the elderly. To prevent being a resource drain, they threw themselves (or were thrown) off a cliff. Things you do for your children, right? [Answer] # Lack of selective pressure for longevity > > Shorter lived humans have outcompeted those with longer lifespans, appearing to make us less fit. What explanation could be given for this occurrence? > > > This is a misconception, although one that has been quite pervasive in ageing studies. There is no evidence that humans have a genetic "kill switch" that can be modulated by evolution: genetic determinants of human lifespan are, basically, [determinants of health](https://medlineplus.gov/genetics/understanding/traits/longevity/), because health failures are the principal age-linked reason of death. Perhaps more surprisingly, the same is true of other animals (with possibly the exception of some eusocial species like [honeybees](https://www.sciencedirect.com/science/article/pii/S0531556507001313)). All known animals basically live until something in their body gives way, even when there is no evolutionary advantage in doing so (e.g. because you're no longer able to produce offspring and you don't contribute to the fitness of the next generation). This extends to stereotypically short-lived insects (fruit flies can live up to 3 months if treated well, by the way). A dogmatic understanding of evolution might make you think that evolution would yield some pressure to get rid of "dead wood" but this is not actually what happens, either because evolution has absolutely no problem with random junk hanging around, or because there is no mechanism to directly shorten lifespan without also affecting health (including, usually, reproductive output). So why doesn't every animal live indefinitely long lives? Because their body does give way, and it gives way with a probability that increases with age. Now we all have repair mechanisms to work against the forces of biological entropy, but they suffer from time-dependent decay as well, and in any case repairs are inferior to the original, and these suboptimal patches accumulate over time (as an aside, the reason the axolotl is able to regrow body parts so efficiently is probably because it makes much better repairs than other animals: if wounded, it [doesn't scar](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0032875) but rebuilds the same skin as an embryo would). So if you want an evolutionary explanation to your scenario, you would have a situation where the repair mechanisms have become less effective. This can be due to active selection, for example because a disease arose that used cells or mechanisms of the wound repair machinery to attack its host; or it could simply be passive drift if repair is not actually selected for. This could happen if, for a sufficient number of generations, almost all humans died relatively young of non-aging reasons. For a real-world example, we all harbour the prion protein in our brain. The progress of "regular" prion disease (not the cow-derived "infectious" kind) is estimated to lead to symptoms of CJD around the age of 200. So we don't have any mechanisms to protect against it, because it would bring no selective advantage. Imagine a version of humanity where almost everyone dies of infectious disease, environmental toxicity or violence around the age of 30: they may not have any pressure to retain mechanisms against stroke, heart attacks or any of the other late-middle-age disease. They may develop a prion variant that kills by the age of 60 and it would go unnoticed because nobody makes it to 60 anyway. When, later, this cause of early deaths disappears, their health-preserving machinery is permanently degraded, and they never recover their original longevity. [Answer] Lifespan was not the trait driving selection. There were other traits that gave our ancestors a selective advantage over more long lived forebearers. Smarts, disease resistance, efficient metabolism, patience with kids, better alcohol tolerance might be some. These fit mutants happened to be short lived. But they left more children whom themselves lived to reproductive age. [Answer] MORE RAPID POPULATION GROWTH Shorter-lived species typically reach maturity faster. The earlier age a female can give birth, the shorter the time between generations will be. If, say, a short-lived female gives birth to 4 children, of which 2 are females, at an average age of 12 rather than 24 for a longer-lived race, the population will double in half the time, all else being equal - and multiply a thousandfold while the longer-lived would only multiply 32 times. This means that the shorter-lived species would recover much faster from any decimating event, whether war, epidemic or natural disaster - a huge evolutionary advantage. Of course, the advantage would be even greater if the species remains long-lived, but matures at a younger age. This would increase the ratio between mature (productive) and immature (unproductive) members of the species, [Answer] Evolution doesn't select for creatures most likely to live longer; it selects for creatures most likely to reproduce, which necessitates surviving to reproductive age but not necessarily much further. Creatures can still benefit their species' evolutionary fitness by helping to raise children even after they cannot produce children themselves. On the other hand, they continue to consume resources, and once they reach a certain age they require care from the younger generation themselves, instead of being able to contribute it. Our morality dictates that we do spend our resources caring for the elderly, but natural selection might favour a species which doesn't need to do this. [Answer] Deny the parasites easy hosts In general, a trait which exhibits itself after a creature has preocreated, cannot be selected by evolution. The genes which cause it have already been passed on, whether they are beneficial or deleterious for the old age of that creature. There are exceptions. Where the children learn from their parents into adulthood, or where grandparents and further extended family play an important role in nurturing children, genes that reduce life expectancy will also impinge on the survival prospects of the children, and will tend to be selected out. Hence social species tend to be longer-lived than similar but asocial ones. What about the reverse? One theory for the evolution of sexual reproduction is that it developed to shuffle the genes of the next generation, so that parasites (which reproduce many time faster) which have become more evolutionarily fit for infecting a parent, acquire no advantage with respect to infecting the parent's descendants. But the child does share half its genes with each parent, so perhaps those parasites are able to acquire some degree of advantage if the parent persists to an older age than is required for raising sufficient children to adulthood? In which case, all things being equal, evolution will select genes which shorten life expectancy, rather than genes which lengthen it. So the answer might be, a deadly endemic parasite with a short life cycle and an unusually high ability to adapt to its host's genetics by evolution. (Closely related, are killer genes such as Thalassemia and Sickle-cell. Why have they not evolved out of the human race, since they often kill before puberty? Because the disease is caused by inheriting two copies of a recessive gene, one from each parent. Inheriting just one copy is beneficial. It gives the individual considerable immunity against the malaria parasite which also causes a killer disease.) [Answer] # The modern economy Consider the modern economy and retirement. Up to the time you retire, you produce wealth for yourself and your family. As soon as you retire, you begin to drain that accumulated wealth. In most societies, even if the elderly is no longer physically productive, they still provide a net benefit to the family via childcare, advice, governance, etc. However, consider what happens if more importance is placed on financial resources. As a very particular example, if we look at the current trend in U.S. medicine, birth mortality is actually increasing, and the cost of medical care continues to climb. If this trend continues, we could reach a point where childbirth has a substantially higher chance of survival for those able to afford the absolute best care, which would require basically the life savings of a middle class family. You could imagine this trend intensifying for various reasons, e.g. moving to a more automated society, where the few jobs still requiring human workers become astronomically expensive and the competition for acquiring limited human services is fierce. The families most able to afford this staggering cost would be those where the older members die soon after retirement, and in particular die quickly so that their deaths don't incur substantial medical bills. If every generation dies shortly before their grandchildren would be born, that inheritance can be spent on better quality childbirth and early childhood care, leading to significantly higher successful childbirth rates. [Answer] Allow this Charlemagne Darwinius a few knowledge ahead of his real-life counterpart: 1. Genetic bottleneck: In your question, you state: > > Recent archeological evidence has revealed that there actually had been a great flood at one point which encompassed the entire world, leading to an extinction-level event > > > Needless to say, such an event would not have affected everywhere equally, leading to some parts of ancient civilization being affected much more than others. Couple that with an understanding that an organism cannot just "make" a new trait, but adapt an already existing part of its biology to express differently, you can argue that the flood had caused all the longer-living people to die off, leaving the shorter-living people. For extra credibility, you can add actual evidence of evolution from our world: Convergent Evolution. The ancient long-living superhuman from the past have died from the flood but as technology, medicine, and safety of your narrative world improved, people start to become longer-living, more capable (through nutrition, education, etc.) once more, thought through a different mechanism. 2. Shorter life is not always a negative trait Most of the answers to this question have stated this already, so I will not add more, but a shorter life cycle means faster adaptation, biologically or culturally ("Meme! the DNA of the soul!"). Furthermore, a shorter life cycle tends to indicate a more r-selected gene, and thus faster to replenish their population in response to environmental changes (like say, a flood, for example) [Answer] The shorter lifespan would have to lead to more offspring. Two possible routes: * The elderly take up resources that could be used to have more children without any corresponding benefit. * The presence of the elderly discourages reproduction. Youngsters feel more free without the eye of the elders, or the reminder of mortality in their parents' death encourages them to reproduce as a means of immortality. [Answer] There's only so much an individual can do Successful evolution in the face of shorter lifespans means a penchant for planning with a view beyond the needs of one member of the species or even one generation. Thus, the shorter life span would inspire or pressure the species to work together for the survival of the many, not just the survival of the one. [Answer] # Faster evolution If you reproduce faster and have more generations in a shorter span of time, then you generate and select for desirable traits faster, thus giving you an adaptative edge. Take bacterias for instance, they can overcome in days antibiotics in petry dishes just by reproducing and dying a lot. [Answer] If this takes place in a world where rapid degradation of living creatures is the norm (for instance, a world with a very high background radiation which damages living creatures, or a world filled with monsters or diseases which tend to cause early injury or death, etc.) than it may be more advantageous for the genome to let existing damaged creatures die relatively quickly and focus instead on creating new "fresh" undamaged creatures which will reproduce rapidly before they too become damaged. Many species follow this path by focusing on rapid reproduction rather than hardy individuals that will likely live a long life. Quicker mutation can also be a benefit in scenarios like these (having the species evolve more rapidly to deal with specific types of monsters, etc.). You may find the biological distinction between "k strategist" species versus "r strategist" species to be illuminating. The comparison table at the following website in particular is worth a look: <https://www.cs.montana.edu/webworks/projects/stevesbook/contents/chapters/chapter002/section004/blue/page003.html> [Answer] Inbreeding. With so few humans on the ark, their genetic diversity was lost. This has caused health problems to build up which resulted in this accelerated aging and shorter lifespans. [Answer] ## Why Do Humans Live Long In The First Place? You've got some good answers here, but the easiest way to think of this is: why do humans live as long as they do now? Adding pressure for shorter lives is unlikely to do too terribly much if there's still pressure pushing for longer lifespans. ## Intelligence = Slow Maturation Humans have a relatively lengthy gestational period (~9 months) and a truly glacial maturation rate (~25 years for full maturation). This is almost completely due to humans having such advanced brains, with evolutionary pressure pushing toward intelligence. Shorter lifespans is going to necessitate a quicker maturation process. To that end, you will either need to a) select against intelligence (unlikely), or b) find a way to develop brain matter more quickly (this could be as simple as a major dietary change - perhaps a massively increased protein intake?). Perhaps these older humans matured much more slower due to an inability to process proteins efficiently, leading to longer childhoods and slower brain maturation. ## Caregiving Humans are well-primed toward civilization. We're pretty excellent caregivers. We take care of children. We take care of grandchildren. We take care of other children. We take care of the sick. We put ourselves in danger to save others routinely, and we glorify people who do so. The social contract of responsibility we have is very much built into us. Perhaps these older humans were even more charitable, with people hundreds of years old still contributing to society and those around them. Take away those positive contributions and you remove a pressure for older ages. ## Cancer This doesn't fit with my general theme, but I wanted to point it out anyway: absent other causes, cancer tends to put a time limit on our lives, even if it might be centuries out. A handful of humans on this planet seem to have genes that defy this, but perhaps that could be a remnant of those older humans. [Answer] Most obviously, evolutionary pressures cannot lead to a decrease in lifespan, be it modern-day human or what. If you care, can you explain what led you to think they might? [Answer] Well, if your god drowned all life on earth, he did a poor job since meermaids ruled over everything for 40 years :D Joke aside, many bacterial and fungal infections (especially after a flood) could force the need to further mutate the genetic code. Like the information theorem: if you happen to have only windows computers in the whole world, nothing would stop a worm of eating them all up in a relative short time. There could be a "coronarious" virus going on for ages, with many mutations, so humans need to adapt and mutate their genome in response. More children == more different dna. Some animals have such a short livespan that they literally only live to reproduce, then die. This is more commonly found in insects. The reason for this? Well, probably they concentrate on the most important thing for their species to survive. Naturally, this would be bad for more "intelligent" live forms who need a lot of time to actually learn motoric and social intelligence. So why only live short? It could be that the time between generations is very huge. Imagine a planet that rotates in such a matter that you practically have like 30 years of ice or storms, then a short period of 20 years in which live can bloom. Naturally this would imply the humans had found some way to hibernate or the likes (magic, tecnology, just laying eggs instead? ) Also, you can always trade a long live for some pretty benefits. Like dinosaurs, they grew to an absurd size, on the other hand that would pretty much limit their livespan notably. Or dogs, better example since it happened through artificial evolution that some are big and some are small, and the small ones live longer ]
[Question] [ So, let’s say a certain type of person steals a Time Machine and travels to Berlin August 1st, 1939. He shows his time machine to Adolf Hitler, and tries to give him advice necessary to win WW2 before it even starts. My question is, what advice should he give? [Answer] Put Guderian in charge of the invasion of France and let him handle things. *Don't interfere or tell him to halt the advance under any* circumstances. If the UK offers a negotiated surrender, take it. Also, don't attack Russia. If you absolutely cannot resist attacking Russia, then be patient; don't do it until after France and the UK are defeated. Again, don't interfere directly with military planning. If you occupy parts of the Soviet Union, don't mistreat the natives. Instead, encourage them to join your fight against the Soviets. Don't declare war on the US just because Japan does. The US has no land Germany wants anyway. [Answer] Don't fight a war on two fronts.** The obvious answer is that the German resources were stretched by attacking Russia while it was pushing into France. On top of it all, they attacked at a point when all the Russians had to do was keep them outdoors during a Russian winter and let many of the enemy soldiers die. Is it possible Russia would have attacked Germany or any occupied territories if Germany had not made that first strike? Perhaps, but (in my opinion) it's doubtful. Russia had an over-supply of manpower, and a gross under-supply of materiel. This is to the point where in many cases they had less rifles than they had soldiers. Also, it can be argued that if Russia had come into the war and attacked German occupied territories, at least the Nazi supply chains would not have been as stretched defending on their own ground, and the German soldiers were (according to many reports) better equipped, trained and disciplined than their Russian counterparts of the day, meaning that they would have made a better show of the fight on ground they understood while they were not freezing literally to death. What does this buy the Germans? Focus. They could have poured all those military resources into the West, possibly taking England in the process (or accepting their conditional surrender). If they had done that, then Winston Churchill doesn't form a de facto international war cabinet and convince Roosevelt to solve Europe first; England falls, America stays out of Europe, content to solve their own problems with the Japanese and then go back to a relatively isolationist policy, and Russia just gets on with building a Communist industrial complex at its own steady rate. Of course, war between Germany and Russia is inevitable at some point, but why not hold off until you can put all your focus into it, your scientists have perfected rocket and jet technology, and you can plan your attack so it doesn't coincide with winter? There are some complexities of course; Germany was still pretty much broke and was building its military industrial complex on the expectation of future gains and spoils, but to me that's all the more reason to focus on one enemy at a time. [Answer] Your [Enigma](https://en.wikipedia.org/wiki/Enigma_machine) isn't as secure as you think. (Followed by: let me explain public key cryptography to you). The allied forces had a significant advantage through code-breaking while the Germans considered it unbreakable. Whether you know or are unaware of the coming ATTACK AT DAWN, this may eventually turn things around. It's your story that makes this work :-) [Answer] No information would help Nazi Germans to win the war - only to avoid it, like fascist Spain did. My first argument - Nazis are Nazi, you can't make them "softer", and they did the best they could Long term war was not a German choice. They planned to end the war with Russia at the end of summer of 1941 (and they almost did it!) and to conquer all "living space" they needed to the end of 1942 (Europe up to Urals and Middle East up to Afghanistan or India), and have a peace treaty with countries left in 1942-43. Germans (and Hitler in particular) were not stupid: they knew more than we do now about battling on two fronts, and that they have not much resources. So they were not fighting on two fronts for five years (39-44) - they concentrated all resources (90%) on one main direction (East-West, then East again) with minor operations on other fronts. Germans were already developing nuclear weapons, rocket and jet engines - before the war. They just had no resources and time to implement all this technology in needed quantities. So any new information would not change much. For example: if Hitler would decide not to attack USSR in 41, but instead "finish" Britannia, Germans would loose a lot in sea operations. While USSR would finish there army modernization and would certainly attack Germans (Stalin also was not stupid - he would knew who would be next) with many thousands of new T-34 and KV-1,2. Yes the WWII scenario can be changed but Germany or, more precisely, Nazi defeat is inevitable. And the root cause is Nazi ideology. No one would tolerate it. Nazi managed to unite too many countries against them. And if they didn't follow this ideology, they would not be Nazi and would not start that war in the first place. My second argument - Any information on military actions would make this information useless. War is a highly random process. And such a process has "butterfly effect": small changes in start conditions make the process to go completely different way (while keeping general "average" direction). So any detailed information about military operations would lead to complete change of military situation in battles. And thus any further information becomes completely inadequate. Batlles would happen in new places with different numbers and positions of troops. And thus "suprises" (bad and good) would be completely new. So "...the best choice is not to play..." - information from future shuold focus on non-military aspects (like "dirty underware" of politics like Churchill), wich would allow Germany to develop in more peaceful way, keeping military actions to local conflicts (sorry, Poland!). But this would lead to unexpected problems with Commis and Japs. [Answer] # Just hand them the history book They don't need technical information, access to the 20/20 hindsight that we have available would be enough to change everything, and if they don't take that hint there's no helping them. There were many mistakes made by all sides in the run up to, and during the war. Given access to that information, advance knowledge of D-Day beaches for example, would make all the difference. Of course the butterfly effect applies when you start playing that game. [Answer] Not really "before WW2 begins" but during the war could reveal things like opponents movements and supplies. If he knew which battles to avoid/write-off, which supply routes were vulnerable, and the advice not to invade Russia could have done a lot to avoid wasting resources and being more effective in dominating. Also, location of various manufacturing plants, opponent supply lines, and responses would let them use more precise attacks to take out opponents. Again, making sure Japan didn't piss of the US until much later probably would have helped with the world dominating plans. If you really want to do it before WW2, then start with the nuclear bomb. Now days, it doesn't take much to really create one. If they just had a few more hints on the process and they could have gotten the bombs out faster. Also, proper encryption techniques. Breaking the ciphers was one of those big things for the Allies, if Germany knew about those or used a more modern suite, that information would have never been compromised. [Answer] You would have to assume a rational German leadership that was willing to act on the advice. If there had been such a leadership, wouldn't they have listened to the German advisors who would have argued against two-front wars, declaring war on the United States, and so on? I don't think there are simple one-paragraph pieces of advice that could make Germany win against the US and the Soviet Union. The Nazis were putting the genocide above winning the war. They were not rational about that. So a briefing kit with the carrot and the big stick: * Documentation of the historical outcome of WWII, including the fall of Berlin and the bombing of Hiroshima and Nagasaki. * A detailed set of plans for Little Boy and Fat Man, and [Mark 12](https://en.wikipedia.org/wiki/Mark_12_nuclear_bomb), for the [Mark 14](https://en.wikipedia.org/wiki/Mark_14_nuclear_bomb) and the [Mark 27](https://en.wikipedia.org/wiki/Mark_27_nuclear_bomb), and plans for the "tools to build tools" like uran centrifuges. * A set of plans for the V2, [Pershing 1](https://en.wikipedia.org/wiki/MGM-31_Pershing#Pershing_1a), and [Polaris](https://en.wikipedia.org/wiki/UGM-27_Polaris) with the [Ethan Allen](https://en.wikipedia.org/wiki/Ethan_Allen-class_submarine)-class SSBN. * Plans for a Mig-17-era fighter and a Phantom-II-era fighter. Of course this data would be impossible to assemble from open sources. Say several notebook computers with optical media plus a pair of dot-matrix printers (their consumables can be produced in the 30s). The computers alone would be a major boost to the credibility of the time traveler. The goal would be to make Germany wait several years before it starts the war. Note how the list includes both "immediate" and "stretch" goals. Imagine a late 1940s, with no war yet and Germany a decade ahead of the historical development in a few selected areas. Then they kick off. [Answer] Considering that Hitler was overconfident in his own military expertise the best advice would be: Let your generals do their job, and stay on the balcony to do the crowd preaching. A country like Germany, dependent on import for supplies, cannot sustain a long term war. It is forced to proceed with small and temporally short jumps. Cutting off all import supplies with a world war is suicidal in the long term. [Answer] If you get to him early enough, have him plan an intelligence operation to assassinate Chamberlain between September 1, 1939 and October 1, 1939. Although Churchill's later conduct of the war as Prime Minister was admirable, in the winter of 1939-1940 his suggestions as a member of the war cabinet were, in retrospect, insane. Churchill states in his memoir The Second World War in the volume Their Finest Hour that he advocated the following policies: 1. An invasion of Eire to seize additional Atlantic ports to conduct operations against U-boats. 2. An invasion of Norway, and then Sweden, in order to cut Germany off from Swedish iron ore. 3. A declaration of war on the Soviet Union in support of Finland and Soviet-occupied Poland. Chamberlain stopped #1 from consideration. #2 was actually approved, and extensive planning undertaken; Germany's own invasion of Norway happened before planning could be completed. #3 actually advanced to the joint planning stage with France, but Chamberlain didn't prioritize it. Had Churchill become Prime Minister earlier - a significant possibility if Chamberlain was killed - his greater energy level and all-around ferocity may have brought one or more of these policies to pass. Any one of them had the potential to lose the war for Britain. All three of them together almost certainly would have lost the war for Britain. [Answer] This question probably requires you to compile multiple answers, as Germany really had a lot of problems it had to defeat to win the war. From resources to production to tactics and treatment of populations. You could tell them how the UK will beat Enigma, and then change a lot of codes and how it works. Additionally you could tell them how compromised their spy network was to give them a headstart. The war would also have lasted a lot longer if the Germans didnt build Tigers and King Tigers, instead focussing on the production of cost effective tanks. Add knowledge early on about sloped armor, rubber synthesis and ballistics of various HE, HEAT, AP and other types of rounds. Dont throw away lots of resources in things like the V1 and V2 rockets. They packed a punch but had too little accuracy to be useful. On that note any artillery and bombardment campaigns that focused on civilian populace should be avoided. Most of the time it just increases the resolve of the civilian and military populace to fight back as partizans or just holding the line. It is also a massive drain on resources for little gain. Also the Nazi's actually figured out that nuclear weapons wasnt in it for them with their resources so you might tell them in advance. Teach them about combined arms, mechanized infantry and whats-his-name tactic about breaching lines and then striking supply lines and enveloping the enemy, of which the Blitzkrieg was the accidental precursor. This should massively accelerate many attacks assuming the Germans can produce it all appropriately. Teach them about war psychology, like instead of firing long lasting artillery barrages you fire 1 salvo every minute. This gives the opposing soldiers time and safety to say "I dont want to be stuck here while death could randomly hit me so I'll just leave", meaning you can capture territory without having to kill many enemies. Get a reputation for good conduct with captured soldiers. If torture, horrendous labor camps and death await you surrender wont be what you'll do. If reports are that you get treated well then surrendering will be an alluring option to avoid death. War isnt about killing but about making your opponent stop fighting! Naturally because they are Nazi's they could still execute and force labor camp prisoners, just make sure they dont find out until they are far behind the frontlines. Consider that America never even knew the full extent of Auswitz, Sobibor and the like until they actually walked into those camps so the option is there. And as others already mentioned, tell Hitler that his generals are capable and should do the job instead of him. If you have good personality reports you can also sift out the incompetents, several of which made it into Hitler's inner circle. [Answer] It might have been too late in 1939 when a lot of scientists had already left, but it might be very useful to focus on nuclear weapons if you go back a little further. Germany had the relevant knowledge at the time, and the Manhattan project took just 4 years, so it seems conceivable that Germany could've nuked other countries into surrendering before those countries got nuclear weapons of their own. It might turn into a really long guerilla war against very angry populations though... [Answer] Watch this video, it explains pretty well what went wrong and how you could solve it. [Barbarossa: The Major Errors and Blunders - or why Barbarossa failed.](https://www.youtube.com/watch?v=A_3R-Rkn_98&t=264s) [Answer] With a time machine it would be relatively easy to give the German side a big advantage. Use the time machine to go back a few years and arrange to have an agent assassinate Churchill. Without the strong leadership provided by Churchill it is likely that a weak and divided British Government would have come to some understanding with Hitler after the fall of France however distasteful that may have been and however unlikely it appears from the modern perspective. Also ensure that the invasion of Russia went ahead as early in 1941 as possible without the time and material wasting excursion into the Balkans (or the Battle of Britain the previous year). Capture Moscow as the sole primary objective and possibly Stalin as well, if he stayed in Moscow (which might not be the case given the changed circumstances). Ensure that the Russian people were treated with a lot more respect to enable the formation of a lot more powerful [Hiwi](https://en.wikipedia.org/wiki/Hiwi_(volunteer)) units and encourage and make better use of [defecting Russian army units](https://en.wikipedia.org/wiki/Russian_Liberation_Army) under German control. It might have been possible to persuade Hitler that this was necessary as a temporary arrangement to save German lives. Finally impress the importance of not declaring war on the USA whatever the provocation. If this is for a story it might also be worth considering some practicalities as well. The time traveller would be going on a hazardous undertaking as nobody would believe they had a time machine on arrival and they probably would not have the correct documentation. If it was possible to demonstrate the time machine to anyone in authority and they became convinced of its reality, the time traveller might get a special audience with the Fuhrer (and the Gestapo might seize the time machine at this point and then all bets are off). [Answer] I'm going to challenge the premise. The best way to win the war is to not start it. Loss was inevitable when they went to tickle the French, the Brits, the Soviets and the Americans, all at the same time. If German authorities churned German Jews and German Communists into German death camps, that's a German problem. What did the Nazis in wasn't the genocide. We let dictators genocide their own people in feigned indignation. Nobody came to invade Germany from 1933 to 1939 when Nazis trampled on democracy and the rights of the Jews and others. France, UK and allies might be miffed about the "Final Solution" if it went into effect, but let's not forget the Great War was supposed to be the last. They weren't eager to fight a Second Great War. So convince Hitler to tone it down with the expansionism. Instead of invading other nations, and powerful ones at that, a better play would be to charm the world through diplomacy and soft power. Take a page from China. Export Nazi industry, technology and arts. Strive to make Nazi sports teams the very best in the world. Make trade not war. If they have valuable, tangible trade to offer, maybe we'll call it a misdemeanour against humanity and leave it at that. [Answer] Additional to other questions that have made good points: The Stug III is going to be your most successful armoured vehicle, with the Pz IV coming a close second. Don't bother going after big heavy tanks, it's a waste of resources, and they won't be influential enough to make a difference. [Answer] Not Much. Germany didn't lose because there were important things about how the war was going to go that they didn't know. They lost because the political leadership (Hitler, Goebbels, etc) refused to accept the facts that their rational military experts were telling them. The German general staff knew fighting on two fronts was a bad idea, Hitler made them do it anyway. The German general staff knew that getting bogged down around Stalingrad was a bad idea, Hitler made them do it anyway. The German general staff knew that if the United States entered the war, they were doomed to defeat, but Hitler didn't care. At the end of the day, there's no realistic scenario where Germany wins WW2. The only reason they ever thought it was possible was because they (incorrectly) believed that BOTH the Soviet Union AND the United States, the two largest industrial powers in the world, would just roll over and surrender rather than fight. Remember that from the German perspective, the Eastern Front was the entire point of the war. The Western Front was just a sideshow to knock France and Britain out of commission so they couldn't interfere with the main event, which was taking over the resources and territory in the Ukraine and the Caucasus oil fields. So, there's nothing you can tell Hitler that's going to keep him from attacking Russia, and there's nothing you can tell Hitler that's going to keep him from fighting a two-front war. And even if somehow he believes you, and even if somehow you can figure out how to attack the Soviet Union without having to fight France, Britain, and the United States at the same time, the Soviet Union could arguably have beaten Germany all by themselves. They had VASTLY more troops, more industrial capacity, and had all the resources they needed, which Germany did not. Without the Western Front it might have taken the Soviets longer to win, but they WOULD have won, and when they did, they would have had control of all of Europe, which at the end of the day was the main reason for the Normandy Invasion. The Allied invasion of Western Europe wasn't NECESSARY for Germany's defeat. Even if all those troops had been on the Eastern Front, the Soviets still would have won, it just would have taken another year. The Allies invaded to make sure that WHEN Germany lost to the Soviets, the western powers would have military control over all of Western Europe. So the Soviets couldn't take it. [Answer] Military information is too specific to influence the whole war. WW2 was not lost in any single battle, and by interfering you change the timeline, so your information quickly becomes outdated. Advanced technology will be of limited use, unless you get plenty of time before the war to update the whole technology base. During the war material shortages plagued the armament industry. This leaves changing the political situation. In the west, neither Great Britain nor France were eager for a war with Germany, nor did Nazi policy look for a war there. The leadership of the Soviet Union however considered a war with Nazi Germany inevitable eventually, and the Nazis saw it as inevitable too. Neither of the two nations was in very good standings but reasonably the Nazi leadership could let Stalin make the first step in conquering the eastern European nations between them. Depending on the situation, Great Britain and France might ally Germany, or even stay neutral. Similarly, the USA would be disinclined to help the Soviet Union. Without the war in the west and the ability to import crucial resources, Nazi Germany stands a much better chance at winning the war. [Answer] Discourage development of the Rätte, the Maüs, the V-series rockets (these would eventually become effective weapons, but Germany didn't have the proper technology), and the Bismarck. Seriously, these were major time wasters. In their place, encourage production of the Sturmgeschutz series. Also, let the guys at R&D finish the [Sturmgewher Project,](https://en.wikipedia.org/wiki/StG_44) as it will produce the weapon off which two of the three most popular guns of the modern age (the AK-47 and the H&K 33) were based off of. Tactics wise, here are a few things you could suggest for them to do: 1. Instead of an air bombardment, go through with Ünternemen Seelow (the plan to invade England). That way, America can't use England as a jump-off point for invasions. 2. Stay out of Greece and North Africa; there's nothing there that Germany needs, and the British are too strong for the Wehrmacht to win in that area. 3. Similarly, stay out of Russia for now. Germany is at peace with them, they are staying out of Germany's business, and Germany does not have enough forces to defeat them right now. If they really want to attack them, then suggest that they at least wait a few years so that they can build up sufficient troops. All this being said, I don't think it would make much of a difference, as the R&D side of things were all pet projects that Hitler pushed through/blocked, and the strategy side is all things where Hitler decided that he was the best strategist who ever lived (he wasn't). ]
[Question] [ When some humans, humanoids and mythical creatures have an incredibly powerful magical regeneration it seems quite obvious that in times of need and growth some countries would try to capture them and use them as ''basic resources''. This is not really a spoiler because it's on the first 2 pages of the book but one example is [Fire Punch](https://myanimelist.net/manga/98270/Fire_Punch), in order to survive a kid is using his magical regeneration to create food and burning fuel by chopping his limbs continuously. One real world example is [Culling](https://en.wikipedia.org/wiki/Chick_culling), basically creatures bred and tortured for the only purpose of creating easily accessible resources, whether such creature dies or lives is based on their ability to produce such resources and being spared and surviving might actually be considered a destiny worse than death. I believe it is historically accurate to assume many kings, queens and people of power would have indeed enslaved such ''people'' and used them for things likes experimentation, food or flesh-shields ... or for pretty much anything actually ... There are different means of getting the magical regenerative abilities, some of them are either training to become a magical healer or simply being born in a magical forest or being born from parents who had this ability, so it is quite common and they are spread across a world with many far apart isles, almost like if our world had been broken into small pieces distanced by water. Technology is mostly pre-victorian and a few empires and nation have powerful artifacts created with a mixture of engineering and magic, those artifacts can be used to create portals, transform lead into gold and other things... but they are incredibly rare. The rest of the world is made by mostly tribes and villages. What is the best way to protect self-healing creatures from being turned into slaves? Religion is excluded because in my setting deities do actually exist but everyone knows they have no say on the subject. A powerful cleric could simply ask a god or goddess if she or he have anything against it and they would respond that they don't care. Yes, the energy and materials needed for regeneration are infinite and come from magic. [Answer] Perfect regenerators are much more useful as a warrior caste than as a slave caste Nobles want to win. In pre-victorian era, that's tied pretty directly to the ability of your armies to win on the battlefield, and in one-on-one fights, and regenerators have a huge advantage there. If you have only a small percentage of your populace as regenerators, you're a lot better off training them as warriors and ensuring their loyalty than trying to turn them into some sort of horrific food source. The real trick is going to be preventing them from taking over the nobility entirely (as entrance into the nobility was also generally based on prowess in battle) Admittedly, there might be kingdoms where they turn their regenerators into food sources... but the kingdoms where the regenerators are warriors should be able to pretty trivially overwhelm them using regenerator armies, free the food-source regenerators, and thus add to the size of their armies while improving morale. (Things like "desperate gratitude" and "freeing kin kept in horrific bondage" will do that for you.) [Answer] If they can choose whether to use their powers or not, they could simply refuse to regenerate when being enslaved and die instead. Edit: As you changed your question to what you could do if it was an automatic process. You could have the cut off limbs magically disappear so they couldn't be harvested. [Answer] Consuming pieces of the regenerators is known to cause undesirable side effects such as uncontrolled growth or mutation of ones own cells otherwise known as mancer the magical form of cancer. While slavery is frowned upon by most nations it still occurs in many forms and will not be completely eradicated until a global shift in consciousness occurs. The regenerators are seen by some organizations as a valuable resource and those organizations will use any means necessary to protect their resources slave or not. Generally strong willed and fearless, it is difficult to force or coerce adult regenerators into slavery. It only works by psychological manipulation from childhood such that they do not even realize that they are a slave. For smaller organizations with limited resources it is not worth the time and effort and for large organizations it is nearly impossible to keep it a secret. Still, the majority seeks to protect everyone from slavery so laws have been enacted and enforced when possible. [Answer] There isn't much historical precedent to suggest that [intelligent, humanoid] creatures would be used as anything "worse" than a slave. Regenerative abilities don't change this. I'm normally pretty cynical, but there were not a lot of cultures which regularly engaged in cannibalism - even of foreigners. This was true even of when it was an explicitly held belief that the natives were natively / culturally superior. I doubt it would make a difference that the foreigners would have their limbs grow back. It isn't just the impracticality of cannibalism that makes it rare in a stable and cultured society. "Civilization" itself would prevent such a gross abuse. There have been terrible atrocities throughout history. Human beings are capable of incredible brutality against "people." But we notice the furthest extremes of that brutality precisely because it is exceptional. Dehumanizing others, working them to death, starving them? Historically not rare. Eating them? Only when society is objectively broken, even by standards much lower than are currently held. [Answer] Magic escape hatch! Your "energy and materials needed for regeneration is infinite and comes from magic." So regenerators are tapped into a source of magic for their powers. If you want them to be unenslavable, have their power come with an escape hatch - they can physically go to the source when they choose, disappearing from their environs and appearing at some designated place corresponding with the source of their power. This could be some temple, or ancient cave; you mentioned enchanted forests so some power grove in the forest. The retreat place might not be the same place for each individual with powers, but probably one source / place would supply multiple individuals. There might be reasons an individual would not want to go there - like it is a long walk back home from there, or they will have to serve the powers there for a time, or they will have to wear a silly hat and eat a bug. Maybe escaping thus is a one time thing and by making that escape they lose their regeneration powers permanently. Or maybe it is into the black - once they go they cant come back; a voluntary death equivalent for individuals that otherwise by virtue of their powers elude death. Whatever you want to dream up that will make this escape method something they don't do all the time but can do in a bad situation. Regenerators could still be made to serve, and might still be slaves, but the people imposing conditions on them would have to be careful not to push an individual too hard, or that individual will disappear and be lost to them. [Answer] It's also historically accurate to suggest the principles of serfdom meant that most of the population were barely better than slaves anyway. Even direct slavery itself was normal until relatively recently and still goes on in many places. The modern concept that people should have freedom really is a very modern concept and any historical setting should include a fairly solid level of slavery and indentured servitude. For your character to not be a slave you'd effectively need them to be a member of the nobility. [Answer] This depends a lot on whether the rulers of this world act like real world medieval nobles did. If the gentry behave like history would suggest, they'd want to turn your regenerating creatures into literal meat for the machine and little short of the ability to resist their will would dissuade them. As such, your self-healing folk have but two realistic courses of action: exodus or rebellion Of the two, exodus in the form of self-imposed exile would happen spontaneously all the time since that's just a matter of individuals choosing to hide where they think/hope they won't be persecuted. However, it's untenable in the long term unless they can find somewhere uninhabited by regular humans to settle in. Attempting to hide in lands ruled by the gentry makes it only a matter of time before discovery and capture. Which brings me to the bloodier option: a rebellion of regenerating folk banding together to fight for their rights. This could easily become a popular uprising if they tap on the grievances of regular human peasants to convince them to join the cause. A clean victory for the rebels would most likely lead to a new nation being carved out, where the regenerating folk rule over their own kind. Otherwise semi-autonomy or power-sharing could be arranged, but these are definitely the less appealing options that would happen only with a win through compromise. In the long run, it's unlikely the regular human nobles will honour such a deal. [Answer] ## Have the regeneration slow down if overused. Take a cue from video games. A character might have a bar that lets them use their ability. If this bar is full, they can use their ability many times in rapid succession—but if it empties, it could take a long time to fill up again. By analogy, give your regenerators a regeneration rate, and a maximum amount of regenerative energy. If their regenerative energy stores are full, they might be able to heal from a thousand sword blows, but if they're depleted, it might take them days or weeks to heal. If you set these numbers carefully, you can make using these regenerators for food simply inefficient. For instance, if it takes two months for someone to acquire enough energy to restore their full body mass, then using them for food simply won't be worth it. They'll have much more value as hunters, for instance, who can bring in twice as much food because they can fight large animals by themselves. Or as soldiers, protecting your country from the unkillable soldiers that everyone else has. Or, depending on how your regeneration does things, as farmers who can work long days without tiring. ## Culture Sure, the gods don't care, but that doesn't mean human beings don't. Cultural customs separate from religion are widespread in the real world, and oftentimes just as strong as religion. Customs prohibiting the consumption of human flesh, or of regenerators, might not be enough by themselves, but they can push other reasons over the edge. ## Put them in charge Throughout the course of human history, people with power have, by and large, used that power to put themselves above others. It may be neither ethical nor inevitable, but it's a common trend. In particular, people who are good at fighting have often ended up with political power. And who's better at fighting than a soldier who can take absurd risks and fight multiple enemies without fear of death? So it could well be these regenerators will end up as the rulers, not the slaves. And if that's the case, they might not take kindly to being eaten. [Answer] There are old soldiers, and there are bold soldiers, but there are no old, bold soldiers. Except if you’re talking about old, bold, regenerating soldiers - they’re off at the pub, it’s happy hour. The trouble with enslaving regenerators is that by the simple fact that they regenerate they become awfully good at surviving very dangerous jobs. And people who do jobs for a long time become quite good at them. Regenerating Captain Ahab doesn’t just lose his leg to the White Whale, he loses it twice more and trades away his arm to get revenge before retiring at the top of his game for something safer, like bear punching. Which is why capturing regenerators for food/experiments is a bit of an unhealthy idea. See for the most part people don’t like getting tortured and eaten and enslaved. And people don’t like seeing other people getting enslaved when they share common ground with the enslaved. Like, say, regenerating. They might get funny ideas, like maybe one day you’ll look at them too and see a delicious long pork roast. And maybe they’ll decide to go work for someone else instead, like that king one realm over that’s been eyeing off that perfect pike to stick your head on. And considering those regenerators seeking employment elsewhere are going to include a lot of those old, bold soldiers (to say nothing of the healers your setting has becoming regenerators!), that’s probably not conducive to your continued survival. No, best not to enslave regenerators. At least not for being regenerators, anyway. (Less roundabout: Don’t enslave regenerators because all the most seasoned warriors will be regenerators and they’ll run off to team up with your enemies if they think you’re targeting them) [Answer] They all regenerate. There's no penalty for their fighting back other than pain. Let's rephrase your question. Why would 10000 wolverines - from the x-men - allow themselves to be taken advantage of like that long term? They're going to hurt anyway. Why not hurt for freedom? It's not like kings/queens can actually do anything to these demigods anyway. [Answer] Have their labor be an important piece of economics. See Brazil for example, when Princess Isabel set the black slaves free it wasn't because she was ahead of her time all loving and caring for the poor slaves. It was because Brazil needed to have more people consuming manufactured goods and the money should flow more freely. A stale economy is a dead economy and slaves are limited, they don't create more technology, they don't consume luxury goods, they don't pay taxes. Have them sell their meat, be the best mercenaries out there, the best healers the kingdom has ever seem. And collect taxes, let the society grow around them as they produce wealth and value. They'll be doing what a slave does, but much better since they're doing by their free will and receiving income from that. [Answer] I've always enjoyed stories where the energy comes from somewhere. Often in anime, it's the consumption of large quantities of food. If it's truly near instant with magic being the source, then I imagine you could use societal pressures in your story. The idea of abusing someone so gifted and blessed instead of using them for their much greater potential could be seen as outrageous, unheard of. That also allows you the option to explore incidents where people attempted to cull regenerators and the responses when they were caught. Cults siphoning blood for rituals, serial killers holding people hostage, government treaties / alliances against those abuses, secret societies of gifted users protecting each other. Instead of searching for limits, your story could explore people's responses and consequences when those ethical lines are crossed. [Answer] They use magic for regeneration. Do they have any control over it at all? What if they stop flow of magic to their regeneration and allow it to build up "a little". When they can not keep flow any longer, all built up energy is released in big boom. Yes, regenerator is killed but people around him or her is also killed by magical explosion. They still can be made slaves but if they think they have nothing at all to loose - they just commit suicide this way and kill at least some captors. Alternative: just make it possible for them to commit suicide by wish (without explosion). ]
[Question] [ ## Premise Suppose a world has no other means to deal with a potentially devastating meteor impact than creating a net on the planet. Their hope is that the massive net will catch the meteor and slow it down as much as possible to avoid apocalypse. They have ample time to prepare for the collision, but there is no miracle material that is invented nor is there magic. We are only in the near future; perhaps this plan is doomed to fail. Doomed or not, this planet wants to build the best net it can. While the design of the net may be important, but for simplicity's sake I'm leaving that out of scope. I want to only focus on the material choice. But, just for fun, one promising design is the hexagonal comb structure that has been time-tested by mother nature to be very strong as well as efficient: [![enter image description here](https://i.stack.imgur.com/isseQ.png)](https://i.stack.imgur.com/isseQ.png) ## Question Which material(s) would be optimal for a massive meteor net to save a planet that is otherwise incapable of saving itself? Further Clarifications: * Budget: Unlimited * Material must be at least known to science, but not necessarily practical / economical * Net Size: up to you * Altitude: I'm not sure if it's fair to consider near Earth orbit on the planet, but it's on the table if need be. The preference is in the atmosphere, but if there is no other way, near Earth orbit is the absolute limit * Net Quantity: you may construct one massive net, or a multitude of nets to function as a system * Support rods: let's not dwell too much on this. Assume they are strong and in place to suspend the net. The weakest point will not be the connection between the net and the rods. That should simplify things for answers on the material. * Lead Time: 50 years * Era: [near-future](/questions/tagged/near-future "show questions tagged 'near-future'") * Planet Properties: [earth-like](/questions/tagged/earth-like "show questions tagged 'earth-like'") * Meteor Size: 10km * Meteor Speed: approx. 18 km/s * Meteor Composition: Unknown (could be solid, could be porous) * Meteor Entry Vector (Impact Angle): 90° * Success Metric: The meteor is contained by the net, and no/minimal damage to the planet surface is sustained (a small meteor crater is acceptable) Points of Interest: Explain why your material is optimal. Here are a few things to consider about the net's material: * natural or artificial material * cost * elasticity * design (feel free to keep the hexagonal net, or opt for your own) [Answer] # No. At the energies involved, no known net material could stop an asteroid which was big enough to be a threat. Even if it could, "stopping" the asteroid still leaves you with all that energy to dissipate. And it will dissipate in a massive explosion. # The energy You can get a rough idea of the scale of these sorts of problems by calculating the energies involved. Using [an impact calculator](http://simulator.down2earth.eu/planet.html), we find a rocky 10km asteroid (a once in 100 million years size) with a density of about 3,000 kg/m^3 has a mass of about 1.6e15 kg. At 18 km/s that packs a wholloping 2.5e23 J. That is roughly the energy if we put all our Uranium-238 in a reactor at once. That's 10 times all our coal reserves going off at once. It's 60,000,000 megatons, 1 million Tsar Bombs. If it hits land, it will produce a fireball over 100 km in diameter and a crater 75 km in diameter and 1km deep. [![enter image description here](https://i.stack.imgur.com/Gg29n.png)](https://i.stack.imgur.com/Gg29n.png) No net of any known or speculated material can stop this. It will pass through it like it wasn't even there. If the net somehow held, whatever is holding it would break. See [World Outsider's answer](https://worldbuilding.stackexchange.com/a/116470/760) for details. # What if the net held? Let's assume the net and whatever sky hooks it's attached to held... somehow. Most asteroids are piles of gravel loosely held together by gravity. The asteroid has so much mass and so much energy it will disintegrate and pass right through the net. A small amount of energy will be lost passing through the net, causing an explosion, but most will be retained. Now instead of one big impactor, you have a shotgun of smaller ones, still with the same total energy. # What if the net held and so did the asteroid? Let's assume the net holds, the sky hooks hold, and the asteroid does not disintegrate. That isn't much use unless we can also stop it. As they say, it's not the fall that kills you but the sudden stop at the end. When 1.6e15 kg goes from 18 km/s to 0, the energy has to go somewhere. Instead of impacting the ground and exploding, your asteroid impacts the net and explodes. How much damage it does depends on how fast it explodes and how high up the net is. The higher the net, the slower it can decelerate the asteroid. We need to make this stop as unsudden as possible, or well outside the Earth's atmosphere where it will do less damage. Of course, in order to stop it we need 2.5e23 J of energy... *handwave. To calculate how fast the net has to decelerate the asteroid, we use the [kinematic equation](http://www.physicsclassroom.com/class/1dkin/Lesson-6/Kinematic-Equations)... $$v\_f^2 = v\_i^2 + 2ad$$ $v\_f$ is our final velocity, 0 * $v\_i$ is our initial velocity, 18 km/s * $a$ is how fast we have to decelerate it. * $d$ is the distance we have to decelerate it. We want to know for a given height above the atmosphere, `d`, how fast do we need to decelerate the asteroid, `a`? So solve for `a` and plug in various values of `d`... $$v\_f^2 = v\_i^2 + 2ad$$ $$v\_f^2 - v\_i^2 = 2ad$$ $$\frac{v\_f^2 - v\_i^2}{2d} = a$$ Plug in our constants $v\_f$ and $v\_i$... $$\frac{0\frac{km^2}{s^2} - 324\frac{km^2}{s^2}}{2d} = a$$ $$\frac{-162\frac{km^2}{s^2}}{d} = a$$ And let's play with some distances. * Maybe your net is hooked between two very tall mountains, 9 km high. It needs to decelerate at 18 km/s^2, or 1800 g's, in one second. 2.5e23 J being released in one second is 2.5e23 Watts or a million times the energy received from the Sun in that time. It explodes. * At 100 km, where space begins, and hung from... something... it needs to decelerate at 1.62 km/s^2 or about 165 g's over 11 seconds releasing 2.3e22 Watts, or 100,000 times the energy from the Sun, into the atmosphere. * At geostationary orbit 42,000 km out, it only needs a leisurely 3.8 m/s^2 for 4700 seconds. This is 5.3e19 Watts or 300 times the power received from the Sun for over an hour. It will be very hot, I'm not sure how to calculate how hot, but you probably don't want to let it get too close to the Earth. If you'd like to know how much damage it will do when "it explodes", I found this delightful paper for you: ["Simulation-based height of burst map for asteroid airburst damage prediction"](https://www.sciencedirect.com/science/article/pii/S0094576517315229#fig3). # Play the long game. If you have enough lead time to build a net, there are much better options. You take advantage that space is really, really big and the Earth is relatively small and it's moving very, very fast. It's a 13,000 km ball moving at 30 km/s in a volume space of millions of millions of millions of km^3. And it's moving at 30 km/s. If you give the asteroid a small but constant nudge early enough it will miss. One [Falcon Heavy rocket](https://en.wikipedia.org/wiki/Falcon_Heavy) produces about 25,000 kN of thrust. If it pushes our 1.6e15 kg asteroid it will [produce an acceleration of 1.5e-11 km/s^2](https://www.wolframalpha.com/input/?i=24,681+kN+%2F+1.6e15+kg+in+km%2Fs%5E2). That's not a lot, but over a year (I don't ask you about your sky-hooks, you don't ask me how we fuel a rocket on an asteroid for a year) it's a [0.5 m/s change](https://www.wolframalpha.com/input/?i=24,681+kN+%2F+1.6e15+kg+for+1+year). Again, not a lot, but over a year that's a 16,000 km difference which is enough to miss the Earth. [Answer] Sorry, there is no way this is going to work. If the net is supposed to halt the meteor by either elastically absorbing its kinetic energy (and then maybe bouncing it back?) or by inelastically absorb all its energy and converting it into heat, it has to mechanically interact with the body. Mechanical interactions in any body propagates at the speed of sound, which for metals is around 5 km/s, and for diamond is 12 km/s. This means that, whatever material one picks, the meteorite will be moving at supersonic velocity into it. Translated, the material will first see a hole in itself, and then notice it has been hit by something, together with the propagation of a large shockwave. The only attempt could be to stack a layer of material with a comparable size in the path of the meteorite, possibly directed against it, and hope that the impact will break it apart (though this is likely to leave a big lump of merged materials around). But since you want a net (either on the planet or laid around in space), I think this is excluded. [Answer] We can do some simple math here to see what our constraints really look like. Let's assume the meteor is mostly made of iron, because I heard that's a common composition in a museum somewhere. Assuming spherical shape, it would be around [3.3 \* 10^16 kg](http://www.wolframalpha.com/input/?i=(density%20of%20iron)%20%204%20pi%20((10%20km)%20%5E3)%20%2F%203). The kinetic energy of the meteor would therefore be [5.3 \ 10^24 Joules](http://www.wolframalpha.com/input/?i=0.5(3.3++10%5E16+kg)+((18+km%2Fs)+%5E2)). We'll assume this is the Kinetic energy at contact with zero gravitational potential energy left. Out of curiosity though, since the escape velocity of Earth is 11.2 km/s, 11.2^2 = 125 and 18^2 = 324, and so gravitational potential energy accounts for at maximum 38% of the total meteor energy. Now the one fundamental thing you have to keep in mind here is this: If you really really really want to stop the meteor instead of deflect it, then that is the raw amount of energy you have to deal with. You can dissipate it, you can reflect it, you can eat it (destruction), but no matter what, that is your the raw quantity of your challenge. This is [a lot of energy](http://www.wolframalpha.com/input/?i=5.346%C3%9710%5E24+joules). It is equivalent to 25 million* [Tsar Bombas](https://en.wikipedia.org/wiki/Tsar_Bomba). How do you absorb the energy of 25 million Tsar Bombas with a net? Wolfram alpha even describes this amount of energy as 11 times the estimated energy of the Chicxulub meteor impact that destroyed the dinosaurs (granted, our calculations are very rudimentary, e.g. sphere of iron). How do we stop 11 Chicxulub asteroids with a net? This is the question you may as well be asking. Thankfully though, you have a very accommodating budget. So let's think of a solution! Again, to emphasize, we have to dissipate energy. When you catch a baseball in a glove, or hit a tennis ball with a racket, the energy is dissipated through sound waves, stress, strain, and friction heat of the catching device. In more extreme catching scenarios, the catching device is specifically designed to break in intentional ways, in order to dissipate large amounts of energy (like [table saws with flesh sensors](https://youtu.be/eiYoBbEZwlk?t=2m35s) or [crumple zones in vehicles](https://en.wikipedia.org/wiki/Crumple_zone)). Probably our best approach for a net is to make it out of something really strong, but not so we can hold the meteor in the sky, rather so the meteor has to spend a ton of energy when it breaks the net. Here is how I envision it You make a net out of tons of carbon nanotubes. You dissipate the energy by planning on the carbon nanotubes breaking. I'm no mechanical engineer, but I'll see what I can do with rough calculating. Apparently researchers have developed high-strength carbon nanotube films with [up to 9.6 GPa of tensile strength](https://pubs.acs.org/doi/10.1021/acs.nanolett.5b03863) before breaking. Say in the next 50 years we get that to 10 GPa (being conservative). It looks like carbon nanotubes usually survive about 15% to 20% stretching before they break. So if we have a net that is carbon nanotubes in one single direction, in a 10km by 10km square, then if force is applied down on the net evenly (such that tension is the main force at play, and we ignore shear forces), we can find out how much energy it costs to break the net at any given net thickness. * Pressure when net breaks = 10 GigaNewtons / meter ^ 2 * Force when net breaks = net thickness \* net width \* pressure when net breaks * Energy when net breaks = force when net breaks \* distance over which the force is applied So * Energy when net breaks = (15% \* 10km) \* (10 km) \* thickness \* (10 GigaNewtons / meter^2), or in other words... * Energy when net breaks / thickness = 1.5 \* 10 ^ 17 Newtons ## And so if we want to stop a 5.3\10^24 Joule projectile, we need a carbon nanotube net 10 Km long, 10 Km wide, and........ ## 36.... MILLION meters thick! [See here](http://www.wolframalpha.com/input/?i=0.5(3.3%20%2010%5E16%20kg)%20((18%20km%2Fs)%20%5E2)%20%2F%20(1.5%20%2010%20%5E%2017%20newtons)) I'm actually impressed!! My first edit of this answer was so incredibly hilariously wrong! at 18 m/s we need 3.8 meters thick nanotube...... but at 18 km/s we need a 36 million meter thick net! Again, at 10 km wide and 10 km long.... 36 million meters is [5.6 times the radius of the Earth](http://www.wolframalpha.com/input/?i=3.564%C3%9710%5E7%20meters). You can also fine tune it, if you look at the formulas. If you increase the stretch distance, you don't need as thick a material. But it will simply never compensate for that raw amount of energy. This meteor catching exercise is basically futile. but fun in any case! The way the terms work out, you can squint your eyes and make a different net depending on how you interpret it. What the above calculations tell us isn't merely, some dimensions, but the fundamentally, the raw volume of carbon nanotubes needed to dissipate that energy with tensile failure. So that totals to 3.6\10^15 m^3 carbon nanotubes. Cutting a few very serious corners, you can hypothetically arrange the volume however you want. A 1 m^2 cable that is 3.6 quadrillion meters long, a 10 km x 10 km cable that is 36 million meters long, or ## A 10,000 km x 10,000 km square trampoline that is 36 meters thick. That is 10^8 square kilometers, which is 67% of the land area of earth, and assumes the 10 km meteor can dissipate the energy EVENLY over that ENTIRE surface. Keep in mind that energy is not the only important factor at play. Momentum is always conserved too. So no matter how you dissipate energy, unless you deflect the momentum, all the momentum of the meteor is 100% going to route through the Earth's crust eventually. Be it exploded nanotube material, or forces through the structure holding up the net, it will all route back down to the Earth's crust eventually. [Answer] the problem with space is that you don't have support to absorb the impact shock. Unless you literally covered the planet with an immense strate of gel, as they do in laboratories to test bullets, no matter how hard the net: that mountain will either shatter it or push it so that in the end you get the net to collapse against the surface. If your civilization has no budget problems and wants to try something extreme, they should build in orbit a BIG brick to shoot with nuclear propellers against the asteroid. Something that has a larger mass and a higher velocity. No finesses, just a rock to hurl against another rock to deviate its course. [Answer] Steel cable, I'm making certain assumptions about the mission profile but my basic argument is that you don't want elasticity and you don't need that much tensile strength so go with something you know and that can be manufactured with existing infrastructure to a high and predictable standard. The mission I'm arguing for is a long-range capture, asteroids follow predictable courses so they can be intercepted at any point along that known track. The net is sent up and makes intercept at very low relative velocity and then uses low impulse ion drives to pull the rock off course with minimal stress transfer to the meteor. I don't think you can use a ground-based net to make the catch once the rock is in the atmosphere, mainly because the rock is going to be so hot that it will instantly degrade any material you might use and melt/tear its way through. [Answer] While other answers have covered that the strict interpretation of your request is several orders of magnitude away from having any measurable effect, there are several marginally more plausible plans which can result from similar strategies. For example: 1. Tectonic plate crumple zone Determine the location where the meteor will land and geoengineer it to absorb a greater than normal impact - for instance disconnect it from the surrounding plate or reduce its density to the point where the meteor essentially passes through it. (In other words - "dig a hole") this may very slightly reduce or contain the damage 2. Ejecta-net The meteor cannot be stopped, but a net designed to catch all the rocks and dust it launches may be very slightly closer to the right side of physics. I recommend starting with a "volcano" shape 100km tall with a 10km wide and extremely deep hole in the middle. If you can engineer it to collapse inwards when the meteor arrives that would be very cool to watch while the world ends anyway. To back this particular plan up with some mathematics, we can consider the optimal version of this to be approximately equivalent to dropping a mountain on top of the meteor immediately as it impacts - if the mountain is heavy enough, it will contain the energy. The meteor, at just under 200 km^3 is approximately the same size as mount Everest (when considered as a cone leading all the way to sea level). Therefore we can assume that adding 1 mount Everest would spread the energy over twice as much mass, and adding 999 would spread the energy over 1000 times as much mass Unfortunately at the next step I am not sure which formula is the right one to use, but to reduce the average velocity by a factor of 100 would presumably require either 100 or 10000 times as much mass to be present. This solution does, therefore, require some extremely large scale engineering 3. Antimatter net. A net made of enough antimatter will prevent the meteor from hitting the planet, mostly because the planet won't be there any more. 4. Redefinition of terms If you build a net in near-earth orbit then redefine "the surface of the planet" to be the net itself and migrate the entire population, it may survive most of the meteor's effects. Good luck. [Answer] Despite all the naysayers I'm going to say yes. Simply because you have infinite time, infinite money, invulnerable supports and all earths resources at your disposal. If we build a new moon as high as possible on those supports and have it impact that it would already soak up most of the energy and blast the rest into space. The big bad problem is mostly that the meteor hits earth, and it stops mattering if it gets to the surface as its energy will be imparted into the earth, all 60.000.000 megatons (from Shwerns answer). But the question is what kind of energy. If you make the worlds largesr single-piston engine with multiple kilometers of ablative material inside to burn through the impact, you can convert a lot of the explosion into kinetic energy and a lot will blast out the topback into space. Then you can spens years slowing the piston down while creating electricity with it. A piston isnt a real option, but I'm just illustrating how important it is where the energy goes and how to store it. Your best bet is losing energy in matter deformation and transformation. Graphene is likely one of the best materials assuming it lives up to its promises. At 5 to 300 times as strong as steel, capable of withstanding a bit more heat than the surface of the sun and very flexible it seems like a good basic element to construct from. Its pure carbon so we have enough material around for a nice, big net. What you do is create a dish. The meteor impacts the center, energy disperses outwards against the sides of the dish and most of the energy and gasses will be blasted back into space. We use reinforced concrete to stop near-direct hits of nuclear missiles of about 320.000 tons of TNT power, this is as thick as 14 inches/a bit less than 50cm. Graphene reinforced concrete is more than twice as strong (<https://www.google.nl/amp/s/www.dezeen.com/2018/05/03/graphene-reinforced-concrete-stronger-university-of-exeter-scientists/amp/>) but sadly I cant find how much stronger pure Graphene would be. Still, Graphene concrete would need a thickness of 4,1km to stop your meteor. Assume that pure Graphene would need less. This is the lining where the meteor hits. The farther down the dish the less material is needed. [Answer] As the other answers say, it's nearly impossible for the net itself to physically stop the meteor. How about instead of the net being the whole answer, it is only part of the answer. Something that has been played with (in books as well as reality) is firing an electron beam at a target, then moving a charged material near to it to cause it to deflect. So instead of the net itself being the stopping force, it is instead a net to allow wide electron beams to be fired through it, while picking up enough of the charge itself, so it gains the same charge, and tries to act like a more material based magnetosphere. The size of the net itself is there to help prevent the mass of the meteors from shifting it. Of course, even if the total charge itself got massive, it still wouldn't be enough to stop anything - instead it's designed to adjust the course of the meteor when it gets close enough to the earth that it's a danger - if it's not quite got enough oomph to get it to skip the planet entirely, it should still give enough to only brush the atmosphere, causing superheated gas and possible some breaking up, but not the major direct impact on the surface itself. As an added bonus, this could be used to fire a net-ball with an integral ion beam towards any meteors - unlike a missile that needs to actively impact to do anything (and still leave the meteor pieces heading to earth), this only needs to get close enough to nudge it slightly, perhaps a cumulative effect with the final line of defence the planet-net - that's normally only there to help de-orbit space junk easily... [Answer] A question is formulated in a nice structured way, and it is sad it turns out so restrictive. And some good answers in that regard already. But generally you need not a material, but a set of technologies/approaches for more active counteracting of the threat. Yes, a 10km asteroid is a big thing and has significant energy stored in its kinetic form. But if you launch 10 times bigger thing from the surface with an escape velocity to collide with the thing, most of the collision debris will fly away. So if the question would be about the ability to counteract the thing from the surface of the earth without humans to be in space or have space technologies then I would say it is possible. It possible in multiple ways, but there a glimpse in one of them. <https://youtu.be/6KKNnjFpGto?t=62> at that time, pay no attention to narration it is irrelevant in the case, it just illustration. [![enter image description here](https://i.stack.imgur.com/G0AJK.png)](https://i.stack.imgur.com/G0AJK.png) There is a screenshot, but it better to be seen in the dynamics. it is possible to reverse the process so a set of waves generated in a material can shoot a droplet out of the system. And such a droplet can be a 10-30km chunk of something heading to welcome our stranger asteroid. in terms of materials what to do or what to shoot, maybe this [article](https://im42group.wordpress.com/2018/02/17/smart-matter-clarification-q1/) may have some use to that, and it may be useful to read the [How can I move a planet?](https://im42group.wordpress.com/2017/07/07/how-can-i-move-a-planet-2/) which it refers to. Matt has "Tectonic plate crumple zone" suggestion in his answer and it may be expanded too. Or we potentially can create a higher density medium on the path of the asteroid, so instead of asteroid begins to blow 20km above earth surface, it may start to do that and more at 100's of km height. but really, it much easier to deal with it in space. ]
[Question] [ Game of thrones has [Orell](https://gameofthrones.fandom.com/wiki/Orell) who uses an eagle to [scout](https://www.youtube.com/watch?v=JleOZg0Ybok) the area. And in the real life, birds of prey have up to 8 times visual acuity of the humans. They are able to see white rabbits camouflaged in a snow from 4 miles away. Assuming we could somehow train them, and/or selectively breed them, to something like a dog level, would they be useful as a scouts in a medieval army? [Answer] # They'd be as useful as dogs, for better or worse Canine units are great at detecting certain things, be it bombs or cadavers or drugs. They are trained through "constant repetition and reward" according to a detailed article from [Smithsonian Magazine](https://www.smithsonianmag.com/innovation/the-education-of-a-bomb-dog-4945104/). A dog will detect a smell of interest and then "alert," when means the dog tells its handler that there's something interesting. It's then up to the handler to investigate further. The dog only gives a notice that the human might want to check out what's going on over there. Expanding this approach to your falcons, you'd send them up to look for something and then they would alert when they found it. What does that mean? Well that depends on how you've trained them. Maybe they learn to look for the enemy's uniform pattern; maybe they look for anybody in a patrol area that's supposed to be empty; maybe they look for specific kinds of weapons. You could train them for any of these things. Their alerting behavior is also up to you. For example, they could fly a barrel roll when they notice something, or maybe they react in a certain way after landing (perhaps because they expect a treat for finding the thing). In short, you have a lot of options. As other answers have pointed out, you can except very low information density from your falcons, just like a bomb dog won't tell you much about the bomb it just found. The real advantage comes from being able to deploy your scouts more effectively. If you know that most of the sectors around your camp are devoid of people, you can send scouts only to those areas where the falcon alerted. [Answer] The simple answer to your question is "no." But let's run with the idea a bit and flesh it out some more. *Could a falcon in either a late medieval or Game of Thrones* styled fantasy setting be used in any way like an [AeroVironment RQ-14 Dragon Eye](https://en.wikipedia.org/wiki/AeroVironment_RQ-14_Dragon_Eye) recon drone? If so, how? If not, why? I picked that particular UAV for a reason. It's small, small enough to be carried by a single soldier in his/her backpack. Its primary surveillance system is visual and its primary control system lends itself rather well to the fantasy half of this answer. The Problem: Communication** Falcons are smart little honkers, and with training can become smarter still. But the fundamental problem with using a falcon for pretty much anything other than fetching lunch is communication. [A falcon's eyesight is wonderful](https://youtu.be/m_DYymYLx2o?t=387), but what's the point of that eyesight when what you need to know is > > In the gulch 2 km from my launch point and 37.5° north of the setting sun are two battalions of Orcs including two supporting mages and 18 ballista. Well supplied and well rested. They appear to be staging for an advance. > > > And what the falcon is actually thinking is... > > [Mouse!](https://www.youtube.com/watch?v=xrAIGLkSMls&feature=youtu.be&t=17) > > > Military engagements, no matter how patterned they may seem, are actually quite chaotic and unpredictable. How to train a falcon to tell the difference between four ninja sneaking through a forest and four skittish deer? How to train the falcon to remember where a previously unknown river is? How to get it to express the idea, "they're over there!" I'll be completely honest with you. I think all the training in the world would produce a falcon that's good for scouting maybe one thing only. And as soon as you changed valleys, it's worthless. *Unless you forget medieval Europe and stick with fantasy Game of Thrones.*** The cool thing about the RQ-14 Dragon Eye is the way it's controlled: the soldier uses a pair of video goggles that let the controlling soldier see what the drone sees in real time. Cool! [Call it fate! Call it luck! Call it Karma!](https://www.youtube.com/watch?v=ZBaGhU7V3jc) Oh, all right... Call it magic! Whatever hand waving you use to explain it — your soldiers need to see through the falcon's eyes, the need to sense what the falcon senses (especially alarm or alertness) and have the ability to "feed back" commands to direct the falcon. This (IMO) enhances your story because while a Marine will directly control an RQ-14 without argument (unless it's fighting weather conditions... or flak...), the falcon may actually have other ideas (Mouse!) and the rustler must coax the bird to do as needed. The relationship between rustler and bird would need to be very tight (e.g., another trainer would be hard-pressed to control the bird if the primary was inconveniently killed. You know, while he/she was zoned out seeing through the bird's eyes. "Sire, Galadriel sees two battalions of Orcs 2 Km from here about... ARGH!") Conclusion So, I think this is a very cool idea, but the simple answer to your question is, IMO, no — no amount of just training will permit a falcon to be a scout to any useful degree before or during a battle. But if you work with the limitations and shake a little Game of Thrones salt and RQ-14 Dragon Eye pepper onto your story, I think that would be very cool. P.S.: I've never seen a single episode of GoT, but I just read @Punintended's comment and I see the OP already had the answer I just presented. My apologies to @Punintended for inadvertently making an answer out of his/her comment. [Answer] Sure, trained eagle scouts could be useful. However, it seems to me that the greatest benefit will come from making your opponents believe that you have trained eagles, whether you actually use them or not. Think about it - every time an enemy camp sees an eagle or bird of prey fly overhead, they’ll get paranoid. They might even waste resources by trying to shoot it down, if they’re suspicious that it’s a trained bird. They’d have to spend a lot of extra (possibly unnecessary) effort to hide their camps in places that cannot be spotted by birds. The psychological effect that this will have on the enemy seems more feasibly useful than birds’ utility as scouts. [Answer] it depends. A raven would be even better as those have good ability to learn languages and speak. also, crows and raven are so common, that most never give them a second thought, not to mention underestimate them. I Live in Alaska, and there, unless you're actually looking for them, ravens go unnoticed. [Answer] Yes, they could indicate the position and direction of travel of a military force which would make them invaluable . The Israeli military are reportedly pursuing a similar concept for covert scouting [Answer] The birds have been trained to recognize and steal enemy decorum. Flags, badges, a knife or arrow? Anything will do! If there is someone in this restricted area, the mission of the bird is to steal something from them. At most, the bird would only be able to use this method to communicate that a possible enemy exists in the territory. No specifics. And there may be a lot of false positives! This behavior exists in birds today, magpies in particular are known for stealing shiny things. Perhaps this behavior could be exploited given enough time and training. Eventually they'll pick the area pretty clean as well! Why don't we train falcons for litter cleanup. . .? [Answer] Ambush detection, flanking maneuvers...etc. That is how I think they make the most sense. See a scout that tells you: hey, there is an army over there. Is not very useful unless they provide exact distance, their numbers, their allegiance...etc. So using them for scouting seems like a complete waste of time. A human soldier with a human eye might take much much more time with a bigger chance of detection. But with the human soldier he will relay exact accurate, most of the time t least, information that will help you draw your battle plans and actually be of tactical value. But an animal that can't answer that won't be so useful. Now a very important point if they can distinguish friend from from foe. Also what type of friend or foe! For example can it tell infantry from cavalry apart? This gets complicated real fast when you factor allies but this is the nature of warfare. However for here is how I see it. General detection! You are marching through thick woods, you use your falcon. The terrain is rough and you need to camp for the night, use the falcon. You you besieging a city and the opposing nation might send allies, the falcon. You are crossing a river and want to find out a good spot, falcon again. Mountain passes, guess what to use Merely using it to report large groups of humans that you know for a fact should not be there could be extra helpful if done fast enough. In all those scenarios you know that there is no detachments of your army or allies marching with you. So the mere presence of large humans is a red flag. That requires less intelligence of course and can be used in a two step verification process. Spot the humans, and send your own human scout while assuming the worse. And knowing the terrain is another part of a scout's job. Lastly it could be useful in actual battles if it can detect the enemy troops and disposition. Might be a long shot but imagine the classical examples of a detachment of the enemy that managed to outflank you. Or in certain cases if the cavalry, usually the most mobile troops so it makes sense, of the two armies were just fighting somewhere and then only one group returns. Well. You better make sure it is your own cavalry that won that battle. Lastly I have to say that they would be used and useful in the field. But by far the most useful thing for them is to aid border control and well as used in castles. Oh man. A castle with such a trained falcon can do so much and have so much time to prepare that it can probably survive whatever siege the enemy has in mind. ]
[Question] [ Lets assume, by the means of some advanced scientific discovery, scientists find a way to teleport simple matter to any part of the world and use this process to teleport fresh water and/or small icebergs anywhere they're needed for drinking water. Question: Is there enough fresh water in the world that is clearly transportable via matter teleportation that the world's [drinking water crisis](https://water.org/our-impact/water-crisis/) could be eradicated? * Assume that the cost of using such a technology in no way prohibits the use of the technology (e.g., humanitarian organizations could easily raise funds to offset its use for those areas where the local economy cannot support the cost). * Assume that teleportation would require practical choices. In other words, whatever is in the water (from the perspective of mass) also teleports. If the water is filled with fish, the fish might not survive the trip, but they'd teleport, too. The practical limitation this creates is that we want to teleport the bulk of water, meaning we can't/won't teleport from aquifers (too high a percentage of rock). That was a long way of saying aquifers shouldn't be part of the equation. * Assume we can't manipulate the data stream, meaning we can't teleport sea water and remove the salt before rematerializing the water. * Assume we are trying to provide the water needs for every fresh-water consequence: agriculture, animal husbandry, drinking water, etc. [Answer] Depends upon what you mean by solving the water crisis and how much it costs, but yes Let's assume that teleportation is truly cheap. The question then becomes is there enough available fresh water to solve the water crisis. The Amazon river has a discharge of about 4.8 trillion gallons per day. This is 600 gallons per day for every person assuming a population of 8 billion. A person only needs about 80 gallons per day for personal consumption including all consumption and sanitation purposes. So problem solved. However, if consider total water usage, industrial and agricultural usage far exceeds residential usage, and 600 gallons per day is not sufficient for all uses. In the US, total water usage is roughly twice 600 gallons/day. Assuming that you are simply supplementing the existing water supply, adding the Amazon discharge alone puts you in the ballpark of solving the water crisis, including industrial and agricultural use. The Amazon is not the only potential fresh-water source, so assuming teleportation is truly cheap, you could solve the water supply problem for the whole world. River discharge would still have to be treated to be safe for use. It is possible that even this treatment results in water that is still too expensive for some areas. So, you still need additional funding supporting water use in some areas. It seems likely that charitable sources would supply the deficit considering the large benefit that would occur. There would also be necessary infra-structure improvements to support dispose of gray-water etc. Again, this can be assumed to be covered by charity or income-transfer from wealthy nations. --- To respond to desalination is cheap, what's the issue. Well, cheap is relative. [Wikipedia](https://en.wikipedia.org/wiki/Desalination) lists the cost of desalination at USD 0.38/person/day (based on 100 gal water per day) This is USD 138.7/person/year -- Not too much for a rich country. But there are dozens of countries where annual per capita GDP is less than 1,000. Too much money for them, they are struggling to buy food already. Desalination would also require lots of energy. Better start building lots of additional power plants (energy is already included in the cost) [Answer] This misses the problem. The problem is not a shortage of fresh water. The problem is a shortage of purification and delivery. Because you don't normally drink water straight from a well or river. You put it into a water treatment plant and then pump it to residences. A teleporter would help with distribution, but you still have the purification issue. You've only solved half the problem. And it seems like the easier half. Otherwise there would be lots of communities using existing distribution methods (people carrying jars of water) with better water sources. E.g. a purification plant that distributes water via wagon to large barrels. People get their water from the barrels. People could use communal showers at the purification plant. > > Assume that the cost of using such a technology in no way prohibits the use of the technology (e.g., humanitarian organizations could easily raise funds to offset its use for those areas where the local economy cannot support the cost). > > > It's important to understand what you are saying. This point claims that teleportation is cheaper than distribution via pipes, perhaps a lot cheaper. Cheap enough to put at least three per household: one for drinking; one for bathing; one for flushing (the toilet). Oh, and a fourth for disposing of the toilet contents after flushing. Although...where? Why not just use one? Because apparently the cost of running pipes is too much (otherwise there'd be no crisis solvable by better distribution). So you have to put a teleporter anywhere you want water to be. And remember that they have no sewage pipes either. Eliminating sewage is at least as big a problem as getting fresh water. And moving it is only a small part of the problem. Cleaning it and rendering it harmless is at least as important if not more so. In general, when they talk about a water crisis, what they mean is that toilet runoff is entering the water supply. This isn't a shortage issue. There's plenty of water. It's a purification and sanitation issue. Not only the drinking water, but the irrigation water and mud puddle water is potentially contaminated. You fix this with better sanitation more than better distribution. Figure out a fix for defecation and urination. Then we can start talking about fixing distribution. [Answer] ## Is there enough fresh water in the world to eradicate the drinking water crisis? Yes, quite obviously The worldwide [total annual extraction](http://www.worldwatercouncil.org/fileadmin/wwc/Library/WWVision/Chapter2.pdf) of freshwater is somewhere around 4,000 cubic kilometers, of which some 3,000 cubic kilometers get to be used and the rest are wasted. The [Amazon](https://en.wikipedia.org/wiki/Amazon_River), all by itself, discharges annually about 6,500 cubic kilometers of freshwater into the salty Atlantic. One single great river carries into the ocean more freshwater than the entire humanity extracts worldwide. [Answer] Yes, it will and it will do so much more. If we could simply teleport water from any point to another, there would be no shortage of water. You don't even need to cannibalise the water reserves of water rich countries or the poles, teleport water in from the outer solar system, where it is super abundant. (The moons of Jupiter and Saturn and the planest Uranus and Neptune consist in as large part of water) Another obvious scarcity it will solve is energy scarcity. Just teleport matter from the lower levels of the sun into a watertank and you have a nearly infinite energy source. (and a nearly infinite source of free weapons of mass destruction) Even if you teleportation is limited to Earth you can obviously transport fresh water and ice. But you could also teleport hot magma up from the center of the Earth to desalinate sea water via cooking. EDIT: Some people have brought up the economics of teleporting water. Unless the cost is astronomically high it is irrelevant. Other materials then water (you mentioned any simple form of matter) can be teleported. Just tap the sun or Earths core for energy. Any economic considerations are gone at that point. You got access to nearly infinite free energy. [Answer] Maybe, depending on how much it costs It is currently possible to transport water pretty much anywhere on the planet. The trouble comes when you factor in if it is economically feasible to transport the required amount of water to the places it needs to be. What you need to work out is whether the teleportation of water will make it cheaper to transport water to the places that need it. Presumably teleportation takes power. If it takes a lot of energy, it might be less economically feasible than just building pipelines or driving water tankers (although it might still save on logistics). If it takes a lot less energy then it would certainly help the water crisis. I expect it would have to be cheap enough for charities to fund it in order to cure the water crisis, as a significant amount of water shortages occur in places with slim-to-nil economic gain so you won't necessarily be able to rely on commercial forces to solve it (at least without significant political pressure). Same goes for the food crisis by the way. [Answer] ## Forget the water. Teleport the moogie! There's plenty of fresh water. The issue is water that's been contaminated by raw sewage from the next village upstream. Since you've got this teleport capability, simply build primordial sewer systems in every settlement that collect the moogie into a focus chamber. Teleport the moogie to a very large and modern sewage treatment plant, probably in a reclaimed former desert now agricultural area. Turn the moogie into fertilizer, and the discharge water into field irrigation. Manage runoff so there isn't any (except during the rainy season perhaps). Processed water enters the aquifer and is therein cleansed. [Answer] * A "crisis" is simply the result of ignoring a problem long enough. * Crises cannot be "resolved" by treating their symptoms. * Treating the symptoms of a problem rather than attacking its causes makes the problem worse in the long term. If a land doesn't have sufficient drinking water, that is almost always the result of a large increase in the use or abuse of the resource. A large increase in population or a large increase in what people do with water will create a water shortage. A large increase in sewage or industrial pollution will create a water shortage. Transporting water, even if by teleportation, would be only a band-aid solution, treating the symptoms but not the underlying causes of the problem. With the addition of low-cost water, people will not only continue to consume and pollute, they will do it at an even greater rate. You haven't resolved the crisis, you've delayed it and ensured that it will be even more difficult to resolve. [Answer] Yes I also think, like @Ynneadwraith says, it depends on how much it would cost and how efficient this would be, but in general I don't think it would (assuming the laws of thermodynamics still apply and you'd need a huge amount of energy to teleport matter. I'd also imagine that such teleportation facilities would rather be very expensive to build and maintain). It is already possible to [turn sea water into drinkable water](https://www.wqpmag.com/seawater-desalination-reverse-osmosis). This would be even better in my opinion since we don't need to split the already drinkable water but could access the [other 97.5%](https://www.nationalgeographic.com/environment/freshwater/freshwater-crisis/) of water we have on earth. Also teleportation of water/ice would probably have a huge impact on the ecosystem it is taken from. Besides some environmental issues the main reason why reverse osmosis hasn't solved the water problems already is [money](https://www.globalcitizen.org/en/content/is-desalination-the-answer-to-water-shortages/). > > So is cost the reason why desalination isn’t used? > Yup. The energy requirements are so high that the cost for a lot of countries is too much. > > > [Answer] Yes. The [Antarctic ice sheet](https://www.infogalactic.com/info/Antarctic_ice_sheet) contains enough fossilized fresh water to provide each of 6,000,000,000 people with 100 gallons per day of water for tens of thousands of years. [Answer] There is no "drinking water crisis". There are problems of overpopulation, both local and global. Drinking water is purely a local problem, caused when too many people insist on trying to live in locations such as Southern California, where there is not enough water to support their numbers. If a large number of them just moved to say the Pacific Northwest Coast, their water problems would be solved. There are also problems of pollution & treatment (e.g. Flint, Michigan) which could be fixed by spending money on adequate water distribution systems. ]
[Question] [ So here's the thing. During the Age of Kings, all the kingdoms in each region of Itheria are at peace for 500 years. They maintain a close relationship with each other and even hold councils every 5 years. They trade with each other every month. All the kingdoms have armed forces enough to fight against the armies of darkness, but there have been no threats against them for almost 500 years. The only threats they face are localized, like bandits and wild beasts. So is it possible for them to maintain peace with each other and maintain their power for 500 years? [Answer] The current longest standing treaty is the [Anglo-Portuguese Alliance](https://en.wikipedia.org/wiki/Anglo-Portuguese_Alliance) which dates from 1386, so history says yes, it is possible for countries to remain at peace for over 500 years. Of course Britain and Portugal aren't rubbing shoulders day to day along a common border, but for much of that period were rubbing shoulders on imperial expansion. Something that led to major conflicts between European powers for the most part, but that treaty held. [Answer] A union or federation of countries You might want to go with a [federation](https://en.wikipedia.org/wiki/Federation) of some kind. In this example each kingdom/barony is its own self managed kingdom, but they collectively meet to decide on the legislation that will affect all countries/states. In this way you could have an entity like the EU, or United States. A super country formed from many smaller countries. The idea of a federation is somewhat flexible, so you could increase or decrease centralized power as needed. For example, no centralized military. The solidarity of these different countries working together over 500 years comes from the fact that they treat themselves as a single larger entity, and then derive benefits from it. For example economic benefit (free trade with each other, bail outs), military benefit (attack any country and you are attacking the collective), and so on. In your case there is an inbuilt benefit of "us vs them". Us vs The Army of Darkness. A super entity like this would be about as stable as a country. So its possible that it could last 500 years. Although like in all scenarios, political and technological change can cause a lot of upheaval. Edit: To add some excellent examples of lasting allegiances from the comments: > > … a historical example that lasted the sort of timescale the OP > is asking about: the Holy Roman Empire. (Unfortunately one or two > little disagreements means that describing the constituent kingdoms as > "at peace" for that time would be a bit of a stretch.) > > > by [@Martin Bonner](https://worldbuilding.stackexchange.com/users/30342/martin-bonner), > > More obscurely, the political alliance of city states in the Indus > River Valley appear to have had at least a 500 year period of peace > given the archeological record, although the peace didn't last forever > > > by [@ohwilleke](https://worldbuilding.stackexchange.com/users/28533/ohwilleke). [Answer] Yes, if some of these conditions were met. 1. Any sustained threat, real or imagined, to all five. 2. No shortage of resources 3. Mutually beneficial trade arrangements 4. Highly defensible natural barriers. 5. Industries dependent on the landscapes 6. Intermarriage and families living in multiple kingdoms In other words, strong familial and economic ties and dependencies tend to make the costs of war high and the means to acquisition of resources far easier through trade. Common cultures and familial ties puts societal pressures on peace vs war as well. Add to that a common threat, even if it's imagined, will keep them united against that threat. [Answer] Yes, if they are island nations. Invasion across a stretch of water is somewhere between ruinously expensive and horribly risky, up to impossible. As I seem to keep pointing out in all sort of contexts, the United Kingdom has not been invaded since 1066, and I believe that since the invention of gunpowder the only way to invade an island with strong coastal defences is to starve it into submission. Which itself is hard, if it is largely self-sufficient. Naval blockades are normally quite surmountable in any case. So the question is, what can the armies of darkness do, that ordinary human armies and navies cannot do? One answer might be, swim! (Swim like fish, 20 or 200 miles, without being sunk by weight of weaponry. Evil mer-people? ) Or fly, on dragons, before the invention of aircraft. Magic would provide any other answer you care to dream up. I haven't researched the history of Indonesia, which might confirm or shoot down my views. I think that's the only archipelago formed of many large islands on Earth. The British Isles have only two large islands. [Answer] # Scavengers All the countries have very similar power. A war between them has very low chances of a meaningful victory, it will be more death than reward since the armies are very similar in strength. But the most important thing is the neighbours: each kingdom is looking for an opportunity to devour another kingdom. So, since the armies are very similar, if two kingdoms start a war it would take a lot of time to one kingdom erode the other kingdom -without losing much strength compared to it- enough to conquer it. It's very likely that during the process, another neighbouring kingdom will take advantage of the opportunity and conquer the weakest one, maybe even both. That is why any kingdom has started a war yet with another kingdom, they are afraid of what could do those "neutral" neighbours. # Each one has something of importance from another Imagine that one kingdom provides food to all of them, while other provides ores and metals to the others, another provides wood and furniture, other provides tools, etc. Each one needs the other 4 to work properly. During the centuries no kingdom was able to become self-sufficient, so all of them needs to trade each month with the others two. That is why no one can make war with another, or they will lose something important. Remember that this doesn't need to be only trade and resources. It can be a powerful shared religion, so the kingdoms are full of sacred places and buildings which can't be profaned with war, or (weirdly) each kingdom has sacred and with a lot of cultural importance relic of another kingdom, so if a war begins the relics will be destroyed. Or simply, there are a lot of political marriages, the royal families are very joined by political, holy and sanguine bonds. # A greater evil All the kingdoms of the region of Itheria are very weak compared to the great kingdom of Airehti (or whatever, maybe even it isn't a kingdom, just a powerful necromancer... like [Ainz Ooal Gown](https://overlordmaruyama.fandom.com/wiki/Ainz_Ooal_Gown)). Only forming a union between them they are able to compare strength with that kingdom and face it. Any war will become the whole region vulnerable to external threats. So the only thing they need is a [charismatic king](https://overlordmaruyama.fandom.com/wiki/Jircniv_Rune_Farlord_El_Nix) who make a pact with all the kingdoms. [Answer] Mutually Assured Destruction To add to the other answers, consider what would happen if one kingdom successfully took over another. Assuming all the kingdoms are practically equal in size, strength, and defensiveness, we now have three kingdoms of power X and one kingdom of power 2X. The newly powerful kingdom is now a threat to the other three, because it has the power to invade another kingdom and if it does it becomes (theoretically) unstoppable. So, either through explicit treaties or an unspoken agreement, the 5 kingdoms remain at essentially a stalemate for 500 years. And if you're stuck in a stalemate, my not make it peaceful and get trade benefits out of it. (I know there's an old story along these lines, but for 3 countries; I can't remember enough to find it) [Answer] > > All the kingdoms have an armed force enough fight against the armies of darkness, but there were no threat against them for almost 500 years. The only treat they face are localized like bandits and wild beasts. > > > This is the most implausible part: that the kingdoms should pay to maintain a standing army which warms benches for 500 years. If you replace the standing army with some kind of militia then you remove that objection and also reduce the risk of war between the kingdoms. If I'm already paying a standing army, it's economically worthwhile to raid my neighbours for booty to pay them; if I would have to raise the money to recruit and train the army before going to war then the cost/risk balance changes considerably. Note: some historical feudal systems had a kind of compromise, where the feudal underlings had to provide so many man-days of military service per year. You want to avoid this for the same reasons. When it comes to an attack from the armies of darkness, it shouldn't be difficult to motivate the population to take up arms. They won't be as well equipped and trained as if you had a standing army. [Answer] Since the kingdoms do not have an external danger, they would fight between them, unless certain conditions are met. * Each kingdom might be tied to its territory due to biological reason, so they are incapable of successful living in other territories. For example, a deadly disease would prevent invasion because the invader does not have resistance to that disease. An historical example is malaria, that prevented european powers to colonize sub Saharian Africa for many centuries. * Certain animals or food might be regionally located due to weather or soil, that would prevent colonization. For example, Bantu expansion in Africa did not reach Kalahari desert, hence, people that lived in the desert was not conquered by bantu people. * Transport is controlled, like the example of Dune world, where no war was possible without the help of the Guild's navigators. * Distance. If distance between kingdoms is huge, is hard to move an army to invade another kingdom. [Answer] My answer is based on the assumption that the time period is medieval or earlier. You define "close relations" as meeting every 5 years. This implies there is no electronic communication or phones, etc. And that transportation is slow. Other things you say (and mostly what you don't say) point to this as well. Instead of looking to which modern nations (spoiler alert: none) have been at peace for 500 years, go back in time to find small nations that got along for prolonged periods. Remember too that what was called "kingdoms" way back then, were often what we would call cities now, with perhaps a day's travel between them. Not always of course, and there were early empires, but often. We see some candidates in [West Africa](https://www.timemaps.com/civilizations/african-kingdoms/). While these kingdoms tended to engage in wars and the like in the 11th century on, it appears that things were a lot more stable in the centuries before then. With some of the kingdoms existing since 800 CE. [Aksum](https://www.preceden.com/timelines/37778-a-crash-course-on-the-ancient-african-kingdoms) in East Africa was pretty stable from 1-600 CE. Ghana in West Africa (also discussed in the above link) began in 300-450 CE and lasted many centuries. And many others. Presumably, there were multiple smaller entities one could call kingdoms that traded with each other reasonably peaceably. In what is now Peru, the [Norte Chico civilization](https://en.wikipedia.org/wiki/History_of_the_Americas) flourished between the 30th and 18th centuries BCE. Several others existed for long periods. We can't conclude that this means they were at peace with their neighbors (or with smaller entities within their borders), but it implies there was stability of some sort. Then there was the [Iroquois League of Nations](https://en.wikipedia.org/wiki/Iroquois). Five nations working together since perhaps as early as 1142 CE. In the early 18th century, a 6th nation joined them. > > The Iroquois Confederacy is believed to have been founded by the > Peacemaker in 1142, bringing together five distinct nations in the > southern Great Lakes area into "The Great League of Peace". Each > nation within this Iroquoian confederacy had a distinct language, > territory, and function in the League. Iroquois influence at the peak > of its power extended into present-day Canada, westward along the > Great Lakes and down both sides of the Allegheny mountains into > present-day Virginia and Kentucky and into the Ohio Valley. The > League is governed by a Grand Council, an assembly of fifty chiefs or > sachems, each representing one of the clans of one of the nations. > > > We can pick apart any one of these examples. I'm sure none of them lived in perfect harmony with their neighbors. But, yes, what you're asking for is possible. In the absence of a more powerful kingdom whose goal is to conquer, smaller states can live pretty harmoniously if they choose. [Answer] It depends. Many kings weren't conquerors, because conquest is an extremely costly act. A reason for war was either: * Resource shortage, e.g. hunger, need for ore * Control, e.g. having control over trade routes, or maybe have access to the ocean for trade * Religion * "Race" * Rivalry * Ambitious plans for expansions, but as said, not many kings had those ambitions Now if none of these factors are present in your kingdoms, enduring peace is very likely, as people need a motivation for war. So yes, it would be possible, given that nothing like natural disasters, plagues, treachery, or any cause of resource shortage happened over that duration. [Answer] They simply need to have strong incentives/influencers to cooperation and to ensuring mutual survival that do not tend to push towards fusion. Various forms of this include... * Having a shared religion with a shared religious organization across all five countries that, for whatever reason, benefits from the status quo. * Something about magic, prophecy, and the armies of darkness that actually blesses the ruling families of each kingdom, and gives each fo them reason to want the others around (because when the armies of darkness come knocking, you want to be sure you have access to the whole set). Bonus points if it's in some way tied to being the rulers of their respective lands (associated with certain immovable artifacts or whatever) It also helps to remove the chances of claims on each other's land. * Clear, unmoving natural borders. Bonus points if they're fantasy races who have no real use for each other's lands. If one (and only one) of your kingdoms is made up of mostly-aquatic people who live on the near oceanic shelf, they're not going to be trying to seize your lands any more than you want to try to seize theirs. * Some way of preventing people from having both meaningful-but-contested claims on Kingdom A and family in Kingdom B * Some clear, well-respected, objective way of determining succession in general * Some massive increased cost of warring between the free people. If every battlefield turns into a place of madness, corruption, and crawling undead, then people will be more inclined to go for peaceful solutions. ]
[Question] [ Imagine a metal canister capable of holding massive amounts of air or some other compressible substance. If it were filled with enormous amounts of said fluid and dropped from a plane, how destructive would it be? I am aware of "lazy dog" weapons that were destructive just because of the weight (and this would be a very heavy canister), but I was thinking the force of the air rushing out of it would be powerful. I can think of three possibilities: * The canister would have to be so strong to resist the pressure that a drop from a plane wouldn't break it * The "explosion" would be loud, but do nothing but scatter dust and shrapnel * A deadly and powerful explosion would ensue as the pressurized air rushed out and created a deadly shockwave of energy I have tried to research it on Google, but the only results I can find are deaths by exploding whipped cream canisters. And they say sugar won't kill you. [Answer] It definitely could act as a bomb. Many teenagers when I was growing up would make "dry ice bombs" by putting dry ice in tepid water in a 1 liter plastic bottle, quickly closing the lid & retreating to a safe distance to watch it explode from the pressure. They were about as powerful as an M-80\* w/ < 1 liter of compressed volume & only the thin plastic of the beverage container to build up pressure. With high performance materials & ultra high compression, you could achieve huge explosions. As the vessel will be under enormous tension & hit the ground w/ great force, it should be relatively easy to ensure failure is abrupt & catastrophic ('an explosion') A lot will depend on what gas you are compressing & what material your pressure vessel is made of. If you're compressing regular air, the oxygen will be a stronger & stronger oxidizer the more you compress it (even if you do it slowly so the temp doesn't spike). I can't find the specifics on this effect, but I'll hazard a guess that by 3500 Bar/50K PSI\\ you would have reached the limits of stainless steel or aluminum corroding if not combusting, but it may be feasible w/ high performance ceramics or fluorine passivized steel or something to hold pressures there or higher. The ultimate theoretical limit of a device like you suggest would probably be if you could somehow use metallic hydrogen. That is, fill your vessel w/ hydrogen, the lightest gas, compressed until it's literally solid metal. It may never be possible in practice, but if you could use metallic hydrogen your bombs would be at least tens or hundreds of times stronger than conventional bombs of similar size. \An M-80 is a firecracker too strong to be legal anywhere I know of \\These numbers are a wild-ass guess, outside my domain of expertise. You've been warned! [Answer] In the world of Hazmat and fire fighting, there is a commonly-known acronym which is related to your question: B.L.E.V.E.: Boiling Liquid Expanding Vapour Explosion - although most commonly planned for with flammable vapours such as petroleum distillates, it can absolutely occur with non-flammable gases such as Nitrogen. [Wikipedia BLEVE entry](https://en.wikipedia.org/wiki/Boiling_liquid_expanding_vapor_explosion) I worked for some time as a tech writer for a company which had a large number of gas storage and flowing systems for a range of gases used in their industrial processes: Oxygen, Nitrogen and Hydrogen; I was also a Hazmat F.R.O., and part of their in-house Disaster Response Team - and I can tell you we very carefully briefed the local fire fighters about our facility and the specifics of our gas system, its shutoffs and controls, kill-points, and potentials for BLEVE* and other similar pressure risks. I think that you don't need a super-high pressure canister - I think you need a canister with *a mix of fluid and flammable vapour, and a heat source directly impinging on the canister's outer skin.* [Answer] You can use the following rough approximation to estimate the amount of energy stored in a pressurized gas: $E\_\text{stored} = p \cdot V$ That is the amount of energy that you can release upon freeing up that gas. So, let's say you want the same energy release of 1 kg of TNT, which would occupy about half a liter volume. That would account for $E = 4.18 \cdot 10^6\ \mathrm J = p \cdot V$. With 10 cubic meters (10000 liters) stored at a pressure of 418000 kPa (about 4000 atm) you could release the same energy. Using a "more practical" 0.1 cubic meter (100 liters) would require a pressure of about 400000 atm. You see it's not the most efficient way of delivering damage. [Answer] Gas rushing out of a ruptured pressure vessel has no [Brisance](https://en.wikipedia.org/wiki/Brisance) so the vessel doesn't tend to break up into many pieces but rather develop only a single breach from which all the gas escapes. This causes reactive motion as the force of the gas escaping pushes the breached vessel away, like blowing up a balloon and then letting it go and it shoots across the room, but with steel instead of rubber. It's dangerous, flying steel is never anything else, but it won't cause a shockwave because it will be a, relatively, slow release, nor would one expect much shrapnel. [Answer] > > I've never seen sugar do that > > > There are a few reports of non-flammable gases expanding (not exploding) in such situations and places that they can kill. For example in late 70's in Poland storage of non-flammable helium had an explosion while filling typical container (the ones used to fill balloons) which created chain reaction that resulted in 5 deaths. Remember that what the gas is doing is rising the pressure. If there is a space for that pressure to run out there will be no shockwave (or it will be very short in range). But if he place is small the pressure can be lethal. Like my nephew who punctured rather large helium balloon in home which resulted in destruction of all windows. The main thing is that such bomb would be far less usable than real bomb. That can be made from a gas canister you attach to your grill. Because here you not only have expanding gas. You have expanding flammable gas. So pressure + flammable + taking out oxygen. And it's cheap and easy to use. [Answer] # Possibly Not Here at STAQXchange Pseudoscientifix, we spare no expense every day to answer your scientological queries. Here are Jen and Lisa, our two highly qualified, intelligent & inquisitive girl scienticians who have taken on the assignment of testing out your query. Jen is up on the mountain throwing a propane tank from the heights down onto Lisa, waiting in the sharp rocks below. Notice how nothing happens to the tank. [Smart Girls Play With Bombs!](https://www.youtube.com/watch?v=j_ja49VHVG0) * RESULT: Not a bomb, sorry! But our Scientological Review Committee thought that perhaps the initial experiment was invalid due to the fact that Jen's canister "bomb" bounced and rolled a lot on the way down, softening the blow. So, here we have Billy-Joe-Rufus-Dean, another one of our highly ejuckated and certifiable boy scienticians, who is going to drop the canister "bomb" from STAQXchange's beautiful downtown Miami corporate headquarters building. Don't mind the warning sirens --- today we're also testing several other astute queries from our admiring public and we feel it is our civic duty to warn pedestrians before we drop heavy objects onto the street below! [Look Out Belooooowwww!!](https://www.youtube.com/watch?v=DN1aKgw66K8) * RESULT: Hmm. Still not a bomb, sorry! Never deterred by two consecutive failures to obtain the right answer, STAQXchange's Review Board Committee decided to give your query one more good old college try! Again, sparing no expense we decided to send Boo, Sticky-G & Ling-a-Ding, our Crack(ed) Team of PhD candidates (Univ. of Cracker Jack) to the very ends of the Earth to perform a final test of your query by, yes, you guessed it! --- throwing a pressurised gas canister into an actual erupting volcano! They figured that would simulate the extreme conditions of being thrown out of an aeroplane. Plus the little pyros got to play with fire. [Hot Stuff Comin' Through!](https://www.youtube.com/watch?v=1R5Qm2A0bO8) * RESULT: Drat. Still no explosion --- still no bomb, sorry! # REALITY CHECK At best, if you drop the canister and it lands in just the right way that the valve & regulator are shorn away from the tank body, the tank can be turned into a slightly damaging missile: Notice that the tank cum missile managed to punch a nice round 10 inch hole in a hollow block wall, plus cause some minor damage to a similar wall a short distance behind the first. [How It's Really Done!](https://www.youtube.com/watch?v=z_Jk_Wlmvbc) [Answer] A bomb? Not well. You have the problem of making the container go from sufficiently strong to contain all the pressure to insufficiently strong to contain any of the pressure in a very short period of time. If you just punch a hole in it, you won't get a bomb, just a rocket. For example: <https://www.youtube.com/watch?v=tyINNUaXa8Q> Now, this could still be pretty damaging, but if you want an explosion you need a way to increase the pressure enough to cause a symmetric, catastrophic failure of the container. I suppose opening a valve to transfer a large amount of pressure from a tank that can easily hold it to a tank that definitely cannot would get the effect you're looking for. Or mechanisms similar to paintball/airsoft grenades, only on a large scale. Or use liquefied gasses. A relatively small change in temperature there would be sufficient to drive a large change in pressure. Or, if they're in a "supercritical" state a relatively small puncture will cause all of the molecules to attempt to stabilize into a gas form, causing a massive pressure spike and possibly an explosion. (This is why steam boiler emergency relief valves have to be not only "big enough", but also not "too big" for the volume, temperature, and internal pressure of the boiler in question. A mistake in either direction can result in an overpressure event.) [Answer] On Mythbusters, they tested this idea in a mock up of the final scene of the movie Jaws (the heroes shoot a gas canister with a rifle, and it blows up, killing the shark and sparing them). While the canister did not "explode" the resulting release of gas was powerful enough that it turned the canister into a rocket, and the shark stand-in used to test for damage was sufficiently ripped to shreds to call the shark killed. Per their policy of "test the conditions, duplicate the results", they were able to duplicate the exploding canister using... C4. What else? The final verdict was "Busted" as the myth was specifically testing the explosive capability of the canister when shot by a gun, not its use in lieu of Bat-Shark Repellent. Note that this myth was retested and reconfirmed as busted, but I don't have the details on the changes to the experiment. [Answer] Your question really needs to first answer, *Does the released gas need to be the direct killing/destructive agent?* Because if not, your opportunities are pretty staggering in regards to, > > The "explosion" would be loud, but do nothing but *scatter dust and shrapnel* > > > Just imagine it going off in an empty parking-lot full of enemies versus a small grove of dead trees filled with enemies; huge destructive and shrapnel potential. Your canister bomb could be incredibly effective in circumstances that exploit the primary means of destruction from the effects of pressure-release, such as affecting the nearby environment and its objects, transforming solids and small objects normally not moving fast enough to cause damage when it becomes deadly shrapnel at high velocities. If the gas itself needs to be the primary cause of death, then your constraints for your designs will be context-specific to where the bomb will be used, and what it needs to compromise with pressure-release, e.g., are we dealing with spacers in EV-suites or Space Marines in powered armor, etc., so then you'd need to answer that question instead. This isn't taking into consideration compounded effects, such as the lethality of the gas itself when not pressurized, e.g. chemical warfare. [Answer] Lol. I truly love these types of sites. Not only is it epic that people have the same questions i have, but some of the answers are brilliant. That said.. i don't believe anyone actually answered and explained your question well. Now I have to ask you to bear with me and hear me out.. because, for one, I have to break your question up to answer it fully. And two, I don't actually know WHY I know any of this. **Assumption: Assume I can, relatively easily, create a tank of air compressed until it is almost solid. Can this tank be considered a bomb? No, oddly enough.. for several reasons. Now you have to understand certain things. An explosion is different from a deflagration, burning, or oxidation. A high explosive will create a supersonic concussion wave that is what does most of the damage near the explosion. This is because the explosive is not only decomposing - breaking into smaller and smaller chemicals that take up significantly more space, but rapidly heating, which adds energy as the wave travels. A fluid leaving a container will almost never be supersonic. All the energy is put in up-front and only so much matter can escape a container at once. This means if we were in a spaceship and I shot a small hole in the hull, no one would get sucked out.. even if i significantly increased the pressure in the ship. And while the container would begin to rupture further, as Ash said previously, it has no brisance since the container could ALREADY hold it.. You'd essentially create a rocket. (Hint: look up ruptures in hot water boilers) Would this tank be a weapon?** oh hell yes. We already know humans are wildly fragile. I also need not tell you that if you were using this tank as a missile, no meat creatures would be coming out intact. But let's say i could make the entire container fail catastrophically... Well.. if you were standing next to, say, a tank that held a cubic meter of liquid air at room temperature. You would not be ok. Liquid air is about 710 times more dense than gaseous air. As this sublimated, you'd be splashed by liquid that was rapidly draining heat to expand. In a neat trick of physics, it would boil off your skin, but any that got in your clothing will freeze chunks off your skin.. Not that you'd notice. The localized pressure burst will not only blast you clean off your feet, but it has ruptured your eardrums and quite possibly your eyes. That is.. assuming you weren't struck by a piece of the shell or a small object nearby as they would be moving at epic speeds. Just note that this concussive "pop" would have a very, very short range.. literally 1 or 2 meters in the above example.. a one meter cube of liquid air would only expand to a 8.9 meter cube.. Compare that to the thousand-fold expansion of TNT and you see why it can't really be a bomb.. ... technically.. .. well.. as long as you popped it outside. You see.. once you liquify air, its components settle. You'd get a nice thick layer of Nitrogen in 2/3 of the tank.. and a layer of pure oxygen. The "make the smallest fire into a conflagration and make anything flammable" type of oxygen. Yeah. Hope you weren't smoking when it went off. But worse.. if you popped a few dozen of these babies in an enclosed building.. it would not be ok. too long; didn't read No you can't technically make an effective bomb out of JUST compressed air, though it is DEFINITELY dangerous, especially in an enclosed space. Just compress a flammable gas. Much more fun. [Answer] > > I've never seen sugar do that > > > Clouds of finely ground sugar, flour, and most other substances that can burn, can cause a [fuel-air explosion](https://en.wikipedia.org/wiki/Thermobaric_weapon). These have destroyed mills and bakeries. ]
[Question] [ In this story, set sometime in the future, most farm animals have gone extinct due to diseases. I remember reading somewhere that the average human has around 100 thousand calories, meaning that one human could last for about 50 days. In a world where humans die very quickly so a lot of humans are born to compensate, could eating dead humans be sustainable for a population of about 5 billion? If not, what other items on such a planet would help support humans? [Answer] # No. What you're trying to accomplish is a perpetual motion machine, just with cannibalism. Over the course of their lifetime, a human will consume 50-100 million calories. As noted, their corpse will only give about 100,000 back, meaning that 98+% of the energy is lost. Even with a shorter lifespan, humans will not break even. Energy is lost through heat and action, and that's energy that cannot be recovered. Oh, and biomass loss. Humans constantly exhale carbon dioxide, losing carbon that used to be biomass. That lost biomass can no longer be used. If you took as a whole the mass of humans, it would have to shrink if they fed on themselves. Sweat, urine, and feces would be other sources of biomass loss. # So what should they actually eat? Plants and mushrooms. Plants need to be involved in any stable food chain. They are really the only way to efficiently add energy into a food chain. They convert carbon and other inorganic materials into biomass for consumers, as well. Mushrooms will do similar. [Answer] This works for most livestock because you can feed a cow (or just about anything else) food that wouldn't be nutritious/palatable for a human. If you have to feed your livestock humans something to fatten them up (and wow, it takes up to 20 years before they're ready for slaughter!), then you could just feed that directly to the non-livestock humans and save the trouble. Compare this to cattle, where you can feed them grass and other plants with zero (human) nutritional value. Chickens can literally peck around eating bugs and what not. Pigs will eat very nearly anything (table scraps, offal, murder victim corpses you want to dispose of). Though we often do feed these animals with stuff that humans could also eat, this only speaks to how abundant food is today in the 21st century, that we can spare that to fatten up livestock more quickly. Cannibalism economics only works when you've got a high population that you want to make smaller, and only for the duration of the "thinning of the herd". Perhaps afterward, if some have developed a taste for human flesh, they might keep human-livestock at great expense... but it will have stopped making economic sense long before that. Counterpoint: Such people (not sure that's the right word here, bear with me) might go so far as to genetically engineer or breed human-livestock that was more economical, but such a project would require long term effort. [Answer] ## Mummies. [![mummyvores](https://i.stack.imgur.com/Yru4N.png)](https://i.stack.imgur.com/Yru4N.png) [source](https://books.google.com/books?id=gGRSDwAAQBAJ&pg=PT19&lpg=PT19&dq=dogs+eat+mammoth+mummy&source=bl&ots=Y_hQYngVZm&sig=ACfU3U2rEZ2mTUwGQIxiCIKMrEzQjnbHmA&hl=en&sa=X&ved=2ahUKEwio7MKxzLz2AhXpnuAKHYuBCmYQ6AF6BAgcEAM#v=onepage&q=dogs%20eat%20mammoth%20mummy&f=false) Your world has a surfeit of human mummies. Maybe the weaponry that caused the demise of these people sterilized the vicinity and they dried out into mummies. Maybe they were frozen by the nuclear winter. Maybe they fell into hypersaline lakes? Or were put there? Maybe the dead were collected and preserved for food. In any case, they are many. When alive these people were not cannibals - they ate at Wendys and Arbys like people do. Now their mummies preserve some of their caloric value to sustain your people. It is not a super long term plan. It will be sustainable as long as your mummy supply holds out. [Answer] # The Net Energy Doesn't Add Up: Entropy means everything goes from a high energy state to a low energy state. So as humans are born and live, they consume energy. Without energy inputs, a given mass of humans would only go down in energy, so a source of energy to add to the system is essential. While you could maintain a population for a short while by steadily reducing the number of humans, eventually, the energy would get lost and there would be no more. So you need a source of external energy (at LEAST a few plants, who can gather energy on their own) to provide the energy fuel needed to keep the energy cycle running. Enough plants to maintain an oxygen cycle would be needed, and someone would need to crunch some numbers about if that is more or less than the number for food production. There would be serious long-term nutrient and prion issues with a predominantly human-flesh-based diet (even if most of the nutrients could be recycled) that would requires some vitamin and mineral inputs to allow more human biomass to be produced. A few genetically engineered yeast might be able to carry out this function. Long-term, you probably want a simple cycle of food production with people eating plants and fungi/yeast, and using human flesh to provide the fertilizer to grow those organisms. That way, you avoid what would rapidly be a massive spread of prions causing a lot of nasty degenerative diseases. [Answer] Recycling human flesh for food would reduce, but not eliminate the other food input that the human society would need. So it could be supplementary but you would still need food input from other sources, albeit in reduced quantity. Which is why some animals eat their young in times of hardship (or if the young die). The young are going to die anyways in times of hardship so better to not let the nutrition go to waste. Like regenerative braking on a car. You can't run continue to run forever solely with the power reclaimed from regenerative braking, but you can reduce the fuel consumption. So yes, it provides nutritional value, but not indefinite nutritional value. [Answer] I wanted to mention that cannibalism leads to Creutzfeldt-Jakob Disease. I'm not a microbiologist so I'm not fully familiar with the process, but eating meat of one's own species leads to the creation and concentration of 'prions' which cause the disease. It's what caused the 'mad cow disease' (BSE) crisis in the 90s - farmers were feeding beef and cow bone meal to cows to boost their protein intake. Instances of CJD also arise in small tribal communities, such as those in Africa, that engage in cannibalism (and yes, cannibalism is still practised in some parts of Africa today, even though it's illegal). So no. For the long-term health of the population, it is not a good idea. [Answer] # This can not be sustained No math is needed to tell you that anything at all that has any kind of waste, and only eats itself, will reduce to nothing. Consider your people like a swimming pool above the ground. After all, this is just about adding and removing calories. [![People are like a swimming pool](https://i.stack.imgur.com/USWCy.jpg)](https://i.stack.imgur.com/USWCy.jpg) Let’s assume your people are like us and they use the toilet, and they breathe, and they have body heat. Those are all calories. Calories leave one human, so they leave all humans. Let’s call calories “water” for now so it fits the pool picture. All of humanity on your planet is “the pool,” and the amount of calories in all of humanity is the water in the pool. OK, like I said. People make heat, they use toilets, and the breathe out. So that happens for billions of people. The number doesn’t matter, but it’s a leak in the pool. It’s calories leaving humanity somewhere. It can be a big leak, or a small leak, it doesn’t matter at all. OK, so water is coming out of the pool now. Maybe fast, or maybe slowly. Now let’s feed all your humanity. It doesn’t matter how much or little they eat, they all eat the same thing. They eat the water in the pool: they eat themselves. The calories come from humanity. So now, you are taking water from the pool, and putting it into the pool. You see? The number doesn’t matter. If you take 200 gallons from the pool and “eat it” so 200 gallons go into the pool, you didn’t add anything at all. Try 300 trillion gallons? That’s a lot of water. But that’s fine, because all those people will be eating it up again—all 300 trillion gallons of it. Did the pool get any bigger? Any smaller? Well, it is getting smaller. You have a leak, and you are adding no water at all from outside. Water goes out, no water goes in, pool empty. Everyone dead. It ends the same with every number. # Is there any nutrition? There is nutrition. What type depends on what you ate. Some diets will make you have more fat, some more protein, and some will have very little value. There is no difference what livestock you use, you get out what you put in. Human nutrition has the same variety as any other animal. A liver has more iron. Bones have calcium. Etc. There is nothing really unique about a human diet that can’t be done with another animal just as easily. And like any other animal, you can change the nutrition by changing what the animal eats and drinks (clean water is essential). You will have no scientific justification for eating human flesh, it will need to be some mystical thing like vampires to be believable. [Answer] You might want to consider the "business proposal" that was floated several times in the early 1900s. The plan was to establish a Cat Ranch and a Rat Ranch adjacent to each other. “To start with, we will have about one million cats. Each cat will average twelve kittens a year. The skins run from ten cents each for the white ones to seventy-five cents for the pure blacks. This will give us twelve million skins a year to sell at the average of 30 cents apiece, making our revenue about $10,000 a day gross. “A man can skin fifty cats a day, at two dollars, and as it will take 100 men to operate the ranch, therefore, the net profit will be about nine thousand eight hundred dollars a day. “We will feed the cats on rats. The rats multiply four times as fast as the cats. If we start with one million rats, we will have, therefore, four per day for each cat. “The business will be self-supporting and automatic all the way through. The cats will eat the rats, and the rats will eat the cats, and we get the skins. Awaiting your prompt reply, and trusting that you will appreciate this opportunity to get rich very quickly.” [Answer] Sometime around 1971, Professor Pat Doyle of the math department at Michigan State University wrote a paper in which he used the standard predator-prey equations, merging the predator and prey variables. The result was a paper with a title something like "An in-eating cannibalistic society could be stable". Someone in the math department might be able to come up with a copy. It was published in an in-house journal. He did it as a joke, I think, but the math was serious. [Answer] ## Laputan and Matrix technology You have more than human flesh to work with. Laputa's finest scientists have developed machines which are capable of reversing the process of digestion... > > an operation to reduce human excrement to its original food, by > separating the several parts, removing the tincture which it receives > from the gall, making the odour exhale, and scumming off the saliva. > > > Of course, the more astute physicists here have noted you can't have something for nothing. However, > > The human body generates more bioelectricity than a 120-volt battery > and over 25,000 BTUs of body heat. Combined with a form of fusion, the > machines had found all the energy they would ever need. > > > [Answer] In terms of food consumption labels, 1 calorie is actually equal to 1 kilocalorie. The term calorie is defined as the amount of heat generated when a material is burned. How much of that energy can be converted by the human body depends on the composition. Fiber has a lot of calories, but null nutritional value, since the digestive tract cannot process it, as does the methane gases in the lower intestine: high calories, zero nutritional value. The same goes for much of the human body...high calorie, but inedible. ]
[Question] [ When writing stories I usually use war as a simple and understandable way to introduce a conflict that needs to be resolved or sweeps the character away. To keep it interesting I need to build versatility into the weapons and gear of the characters. After all at best I can say "he hits/misses". It's everything around it that matters: what the characters do, what they have available, how they react to the situation, how they react after it's conclusion, what they do afterwards and how they react the next time. For this reason I look at various things like gadgets (jumpjets) and the choice of weapon they carry. A sniper is relatively boring. It's the penultimate "your shot hit or misses" weapon. It only becomes really interesting if you fight another sniper or create situations where they need to use environment (thunder) to hide their shots. It's severely limiting in the type of story you tell. A machine gun or rifle offers more versatility for a story, but the weapon I go to is the shotgun. It is a close-quarters weapon and allows me to let the characters get into hand-to-hand combat, you can equip a large variety of slug ammunition and it is far less clean than the "hit enemy far away and ignore the bodies aferwards" storytelling I dislike. Among the ammunition I would want to have armor-piercing slug ammunition. However general concensus is "this slug I heard off didn't have the speed and couldn't penetrate so none can". So I want to have a solid and above all complete answer on how exactly an armor-piercing shotgun slug could be fired by a shotgun, or why not. For reference: many sniper rifles have shorter barrels, even the anti-material rifles have a maximum barrel length akin to that of some shotguns and the closest size in barrel diameter. Yet when people talk about shotguns it is a solid "impossible" with statements of what some slugs can achieve rather than what is possible. To make the title clear with my full question: How could a shotgun fire armor-piercing ammunition effectively? Extra information: * this question is about both the shotgun and the slugs. If you need to redesign both the shotgun and slug to be effective that is possible, as long as the shotgun remains a shotgun in functioning. * this question is about what is POSSIBLE, not about a list of what is not possible. If you have something that makes it impossible, explain what would be necessary to make it possible and why that is unattainable. * the answer with the best AP ability is the best answer, unless a reasonable and detailed answer can be given explaining why it is impossible. * a lower accuracy is acceptable as long as it's not a cointoss to see if you can hit the side of a proverbial barn. [Answer] Generally, armor piercing ammunition is high velocity, and high velocity in firearm rounds is inseparable from high chamber pressure. Problem is, a shotgun is a low pressure weapon. Typical shotgun chamber pressures run around 15000 psi (approximately 1000 bar, 100 MPa), while high velocity rifle rounds typically run three times that level. So, in order to get a high velocity from a shotgun, you've have to use the other method: a very light projectile for its bore size. This points to discarding sabot rounds, which have been sold in various forms for rifles and muzzle-loaders for decades. With a discarding sabot, it should be possible to get a bullet comparable to a common 7.62 mm rifle slug to a velocity roughly similar to the 900+ m/s (~2800 ft/s) you'd get from a military rifle, which is fast enough for an armor piercing bullet to work the way it's supposed to. Unfortunately, there's another problem: the smooth bore. An armor piercing bullet needs to strike pretty precisely nose on to shed its windshield and let the penetrator, well, penetrate armor. Without rifling, the round must be aerodynamically stabilized (as is the case with most kinds of common shotgun slugs -- they have a heavy end, which travels to the front, and a light end, that acts as vanes to stay at the back). In the end, you wind up with a projectile that looks rather like some modern tank rounds, specifically fin stabilized armor piercing (the main gun on an Abrams tank is a smoothbore!). This round uses a "piston" base to seal the bore and get the most possible propulsion from the powder charge (while staying within the shotgun's rather low pressure limits), is very light compared to common slugs, and once it leaves the bore, separates from the piston to become what amounts to dense, hard metal arrow. Assuming the physics works out right to get the velocity needed, this should penetrate body armor and even light vehicle armor as well as a round from a 7.62x51 NATO chambered rifle. There's one other slight issue -- accuracy. There is simply no way for a smoothbore round in this size class to be as accurate as a rifled one. A match grade rifle can shoot to accuracy of better than a minute of arc, giving a useful range of more than a kilometer. A tank gun (also a smoothbore) is about that good (though some of that is due to its targeting systems). A shotgun, on the other hand, has a relatively thing barrel wall that is easily deformed, and typically isn't equipped with a scope sight as you'd see on a sniper rifle. They can be accurate enough for hunting to a range up to a couple hundred meters/yards, but that's hitting a pie plate, not an ear. This means AP rounds for a shotgun will have a relatively short effective range -- not because (like normal shotgun ammunition) they lose velocity quickly, but because they have limited accuracy. They'd be effective to a couple hundred yards/meters; beyond that, if they hit, they'll still penetrate out to double that range or more, but the probability of a hit drops off pretty badly. [Answer] Taofledermaus has your answer. [Custom SHOTGUN Slug DEFEATS AR500 Body Armor](https://www.youtube.com/watch?v=voM13PNFYZI) [![polycarbonate slug](https://i.stack.imgur.com/xZfSP.jpg)](https://i.stack.imgur.com/xZfSP.jpg) [![armor plate](https://i.stack.imgur.com/C3KMK.jpg)](https://i.stack.imgur.com/C3KMK.jpg) I was thinking - OK, how about a 8 gauge goose gun with an aerodynamic tungsten slug... Then I realized that this channel is all about that kind of stuff, which I know because I have watched a ton of their videos. This polycarbonate slug is not very heavy - it is basically plastic! It was fired from a standard shotgun with birdshot-type propellant. It flew like crap and so innovations from other slug types (as seen on this channel) could be used to improve aerodynamics. In fact the maker of these slugs did exactly that as shown in a later video, [using an air rifle pellet shaped carbon fiber slug with a similar tungsten penetrator](https://www.youtube.com/watch?v=SHjucO8Qfqs) So large, low density, low velocity. But that tip in there is tungsten carbide which is super dense and very hard. It was delivered to the armor plate by the plastic, and the tungsten penetrator went right thru and also right thru the big squash behind it. So - not overpowering the armor with giant masses and velocities. Delivering a small and very hard penetrator is how these armor piercing shotgun shells work. --- For your fiction might I suggest different schools of thought as regards optimal custom shotgun shells for their applications. Your characters can debate, point out flaws, mock, admire and generally engage one another over these issues which as you state is the stuff that drives a story. --- @Nepene Nep - check out the video. After this plastic and tungsten weirdness, they try a sniper rifle against the same plate and squash. No dice. [Answer] There are many ways that modern munitions can defeat armor. Most traditional firearms do it with a hardened metal jacket or tip, but getting the velocity you need for this out of a stock-shotgun is not really doable. Even a saboted round will only get you up to an okay level of penetration. So, instead of looking at how riffles pernitrate armor, you could try looking at how RPGs do it. Anti-armor RPGs have much lower muzzle velocities than riffles, but use a larger projectile assisted by impact explosives. Converting a shotgun into a mini-RPG like weapon is a pretty trivial task when you consider how similar they are. Your best options are probably going to be a HEAT or HESH type round: A HEAT round uses a detentator pin that leads in front of the shell to set off a shaped charge just before it impacts the target. This directs the explosive into a narrow high energy stream the blasts a tiny hole through the target filling the area behind the impact with a spray of VERY hot metal. A HESH round is tipped with a plastic explosive and places the detonator cap at the very back end of the projectile. This way the slug spreads the explosive out against the target before detonating allowing for a maximum amount of energy to be transferred into the target which then relies not on penetratingly the armor, but sends a shock wave through it. [![enter image description here](https://i.stack.imgur.com/RuRiC.png)](https://i.stack.imgur.com/RuRiC.png) I'm not sure how effective a HEAT or HESH round would be against a Lightly Armored Vehicle because even if you beat the armor, filling the cabin with enough HEAT spray or spalling debris to take out people inside with such a small round would be hard, but if your goal is to beat Class III or IV body armor, either solution should do fine. When your armor is pressed right up against your squishy bits, the shockwave of a HESH round would cause MASSIVE internal injuries even if your armor technically stops the shot, and a HEAT round does not need to fill an entire vehicle cabin, just the area directly behind the impact point. Here you can see what happens when you turn a slug into a high explosive armor penetrator: <https://www.youtube.com/watch?v=8Lpx_CQ6kwo>. While this video is labeled a HESH round, it's actual configuration appears to be some sort of a bastardized hybrid between a HESH and a HEAT round, but either way, you can clearly see just how much extra power you can put into a target, even with a relatively small explosive shell. [Answer] Sniper rifles. They can target vehicles, threaten people who you call, kill passerbys, disable communications, do lots of things in chase scenes, and do lots of things outside of just killing. Snipers have a wide ability to influence their environment. They also have a voyeurism aspect where you can spy on stuff you're not supposed to see which can make for fun scenes. Sniper battles are popular in fiction, for a reason. Armor piercing shotgun rounds You can make saboted rounds that can penetrate armor. The common criticism people make is to John Wick 3 which had rounds that wouldn't penetrate based on their nature, but you can make fairly narrow ones that have a spike that can penetrate armor. It would be weird from a military perspective since rifle bullets penetrate armor much better, but shotguns tend to be more legal than rifles, so there's some market for such weapons. Such rounds are a lot more expensive than normal shotgun slugs (5-10 times more expensive), but that's not a big issue for many story protagonists. Shotguns are widely legal, mostly short ranged weapons that are cheap to make and run, as a general matter. Shotgun slugs are cheap to make and great for handling within 100 meters targets who lack armor. Making them armor penetrating is expensive, but possible with enough money. You can also use explosive shells, which are also very expensive, to improve penetration. [Answer] I would like to go with the simplest answer here, as the other answers are awesome and cover things like SABOT rounds excellently. Shotguns can fire frag grenades. So, yeah that takes care of most armor, but it gets better. If you haven’t seen it already, look up the AA-12. Go on, I’ll wait here. Got it? Ok cool. This is a fully automatic shogun with 100 and even 200 round drum attachments that can fire 12 gauge frag grenades multiple times per second. Any kind of personal armor will soon be rendered completely superfluous. For some bonus points you could also consider incendiary rounds. Armor doesn’t matter if the person wearing it is on fire. Also you could probably make a shotgun fire sticky explosive rounds pretty easily, but you would have to reduce the muzzle velocity, thus hindering range. You could also use flechette rounds, which is a bundle of super hard, thin, razor sharp needles that can defeat armor fairly well. BUT WAIT, I’m about to blow your mind again! The easiest method for dealing with body armor when using a shotgun is…. Firing normal slugs. Will they penetrate? Probably not. Shotgun slugs are big, soft, blunt, and (relatively) slow. However, what they will do is dump lots of kinetic energy into a tiny little spot. This tends to do things like break bones, rupture organs, cause internal bleeding, and a generally rough few days afterward. Though it may not be lethal, in many cases it is better to disable your opponents instead of killing them. This not only takes them out of the fight, but also their friend who now has to drag their buddy back to safety. So 2 for the price of 1! A few important points you may want to remember. 1. Shotguns have longer range than most people think, but not anywhere near the range of even the most basic rifle. 2. Shotguns only carry around 8 or 9 shells unless they use a magazine, and you usually have to reload shells one at a time. 3. Shotgun shells are very heavy, their magazines are much heavier, which limits the ammo you can carry. Modern militaries do use shotguns, usually as a breaching tool, though they are extremely useful when it comes to clearing the building you just breached. They are great for any close quarters fighting because of their stooping power, but remember, a rifle works just fine at close range too, and it works at ranges a shotgun can only dream of. None of these points means that this premise won’t work, but depending on the audience, tone, and scientific accuracy of your story, you may want to consider them and develop a reason why your characters are using shotguns over rifles. Remember, rifles can pierce armor too, and some sniper rifles can pierce 1 inch think steel plate from over a mile away. Also! If you would like to research specific, commonly used weapons here you go! Shotguns 1. R870 Wingmaster: Possibly the best selling shotgun ever, definitely the best selling shotgun in America, fantastic weapon and very commonly used. 2. Mossberg 500: The number 1 European shotgun and commonly used by police and militaries all over Europe. 3. AA-12: Possibly the coolest shotgun ever, full auto, recoil dampened, titanium barrel and frame, pure awesome. Rifles 1. M4 and variants: Long range, high fire rate, 5.56 caliber ammunition but can be converted to .50 caliber pistol rounds. NATO’s favorite weapons system. 2. AK-47 and variants: Usually 7.62 caliber rifle with heavy stopping power but lower accuracy and fire rate. 3. SCAR and variants: NATO’s counter to the AK, also often 7.62. Hard hitting with better accuracy and highly modular design. 4. Tavor: Very cool, bull pup in 5.56 and 9mm, short, excellent accuracy and fire rate, and the 9mm version can be silenced very well. Sniper Rifles 1. Barret .50: Semi auto sniper rifle, technically an anti-material rifle, effective range is around a mile and a half though the bullet is still lethal at much longer rangers. 2. M-200 intervention: Maybe my favorite sniper of all time. 408 Cheytech rounds, basically a necked down .50 caliber casing with a smaller bullet. Flatter trajectory, effective range out to either 2 or 2.5 miles. It’s also bolt action which means very high muzzle velocity. 3. .338 Lapua: Technically a round and not a rifle, but often called the best sniper round ever. I don’t have as many details on it as the other rounds but it is exceptionally accurate. Hope this helps! [Answer] There is a company called Firequest that make exotic shotgun ammunition. While the incendiary dragon's breath is more well know, they also make flechette rounds with steel darts and armor piercing rounds they claim can penetrate 1/4 steel. [Answer] # It depends on what you mean by armor piercing, and how far you want it to work from. Armor piercing rounds generally fall into one of two categories: kinetic penetrators, and explosives. Kinetic penetrators work by hitting a relatively small spot on the armor with a very hard object moving at high velocity. Most modern AP rounds for rifles are kinetic penetrators, utilizing a penetrator core made of steel, tungsten, or some other hard (and ideally heavy) which is either surrounded by an outer layer of some softer material, or carried down the barrel by a sabot that falls off when it leaves the muzzle. The standard alternative for a smoothbore gun is known as an Armor Piercing Fin-Stabilized Discarding-Sabot round, and is essentially a big metal arrow carried down the barrel by a sabot that falls off when it leaves the muzzle. Explosives are a bit different. The two primary designs are High Explosive Anti-Tank (HEAT) and High Explosive Plastic (HEP, sometimes also called High Explosive Squash-Head or HESH). HEAT rounds utilize a shaped charge and a layer of metal to produce a narrow, high-velocity jet of superplastic metal which punches through traditional armor a bit like a plasma cutter (though it does not rely on any kind of thermal effect). HEP rounds, in contrast, consist of an impact trigger with a bunch of soft high explosive putty which flattens out over the surface of the target before being detonated by the impact trigger, causing a shockwave in the target that leads to spalling. Kinetic penetrators can work for smoothbore guns, but they need a very high muzzle velocity to be effective, and therefore a rather high chamber pressure. Explosive rounds, in contrast, do all their damage with the chemical energy carried by the explosives, and thus don’t need to be moving fast and therefore do not need a high muzzle velocity or chamber pressure. Shotguns, by their very design, do not have an especially high chamber pressure or muzzle velocity. A typical 12-gauge shotgun slug has a muzzle velocity of about 500 m/s, significantly faster than a 9x19mm round from a handgun, but significantly slower than a 7.62x51mm rifle round. That’s honestly not fast enough for a kinetic penetrator to have useful armor penetrating abilities past about 100m. However, it’s actually more than enough for an HEP or HEAT round to work reliably at a range of maybe 300m (about the same effective range as a typical assault rifle). There are two other issues here though with a shotgun for this purpose: * The accuracy is horrendous. Shotgun slugs have generally poor accuracy compared to rifle rounds at equivalent ranges, and it’s even more of an issue with HEAT or HEP rounds because those are much more sensitive to the angle of impact for their reliable operation. * The amount of explosives you could use is significantly less than useful. Simple math indicates that a HEAT round fired from a 12-gauge will only have a penetrating power of about 125mm of traditional armor plating (not the modern composite stuff, but classic ‘block of steel’ style armor plating), and an HEP round will barely have enough energy to do anything useful. They may work against personal body armor, but are likely to be useless against a modern tank. --- Now, all that said, I actually agree with you that a shotgun is a good choice of gun if you want versatility. It just isn’t really any good for reliably dealing with armor. So the proper solution is to just use a shotgun as your main weapon, and then have something else for dealing with armored targets. If you’re going for the rule of cool, I’d probably go with the insanity that is the Triple Action Thunder. It’s a single-shot breech-loading handgun chambered in 12.7x99mm (the de-facto standard anti-materiel round among NATO countries, better known in the US as .50 BMG) that never made it past the prototype stage. It’s wholly impractical (you get one shot, and then it takes about 30-45 seconds to reload properly if you have practiced and have another round immediately at hand), but that in and of itself makes it a potentially good option for storytelling, because you can lean on that impracticality as an exploitable weakness in the character’s arsenal. [Answer] * A shotgun could fire better, more armor-piercing shot. The improvements are limited, but the [HK CAWS](https://en.wikipedia.org/wiki/Heckler_%26_Koch_HK_CAWS) was designed to fire tungsten pellets as well as old-fashioned shots. The increased density and hardness improved the armor-piercing characteristics slightly. * A shotgun could fire specialized slug-like loads. Ordinary [slugs](https://en.wikipedia.org/wiki/Shotgun_slug) are short, fat rounds. But there are saboted slugs as well, and the projectile could be relatively slim and pointed, much like a modern [long rod](https://en.wikipedia.org/wiki/Kinetic_energy_penetrator) tank round. * A shotgun could fire shaped-charge explosive rounds. There are shotgun shells with [explosive grenades](https://en.wikipedia.org/wiki/FRAG-12), and the lower size limit for shaped charge rounds has been dropping for decades. Improvements in the fuse etc. might make 12-gauge shaped charges practical. [Answer] You could use the shotgun, or a shotgun like weapon, to fire a primary shell loaded with high explosive which then on impact explodes projecting shrapnel all around. Advantages: * if you overshot the shrapnel can hit your target on the back. It can be handy if the body armor is optimized for the front * it makes hiding behind repair less effective for your targets * it has a heavy psychological impact on the targets Disadvantages * I suspect it violates some convention on the weapons allowed in war * the shrapnel projection needs to be designed to protect the person firing it from being hit [Answer] Could it? Yes. I would note most of the ideas above, while certainly correct and feasible, take away the spread capability of a shotgun in order to gain armor penetration. There's not many ways around that. If you want to maintain shot spread along with armor penetration the best way I can think of is also submunition-like, namely some kind of thermite shot. Thermite is a material that burns very, very hot. Militaries often use it in anti-material devices. It also is very easy to make. The only problem is that igniting it is difficult. Even a blowtorch would do little more than tickle it. Burning magnesium is often used as a fuse for thermite. You could pack a shell with powdered magnesium and thermite pills with some heavier powder. It would spray extremely hot projectiles that would burn through pretty much anything they touched. They would be fairly short range. The magnesium burns very bright as well - it's often used in flares and flashbangs. You also might chew up your barrel badly by firing them. Magnesium burns fairly hot and ignited thermite is not something you want in your gun barrel. If the slug was instead a submunition that launched and then ignited its payload in flight it would be less harmful to the firer. Disregarding thermite, any burning metal is a pretty tough thing to deflect. Magnesium is easier to ignite, but some Lithium alloys and mixtures would be quite effective. It is pretty hard to ignite, but nearly impossible to extinguish. A burning gel like napalm could also have a shot-like spread effect and be effective. Burning chlorine and phosphorous would also be poisonous and would likely cause fairly instant choking. Inhaling the scorching gas while coughing/choking would also not be good (which is why using them as weapons is banned - in this world). Sodium ignites on contact with air (Oxygen), so firing a cluster of traditionally-sized pellets that are lead-encased sodium would be quite a surprise. I'm not sure if sodium burns hot enough to defeat soft body armor, but it would embed and ignite in it. [Answer] # INKUNZI PAW (NEOPUP), STOPPING RIFLES AND UNDER BARREL GRENADE LAUNCHERS there are several problems with your armor-penetrating shotgun: 1. Shotguns are made with thin barrels because they do not need to contain high-pressure cartridges. 2. Shotguns are made with thin barrels because the payload receiving the momentum is heavy and slow (and thus does not have an enormous penetration) 3. There are easier and better solutions to high penetration. It is always a trade-off between weight and speed with non-explosive projectiles and it is much more user-friendly if your gun does not have enormous recoil from accelerating heavy bullets to high speed under huge pressure. 4. It is much easier and pleasant and reliable (less error-prone on the construction of the things) to create a lighter (but not too light) projectile and give it higher speed (up to a point). Your armor-penetrating shotgun is going to weigh a ton and have a kick that would probably break a wrist and a shoulder of anyone shooting the thing if the projectile is going to rely on speed/size combo for armor penetration. That will make it really unpopular for anyone who has to carry the thing for a longer amount of time and use it for more than a couple of shots. 5. Large and light projectiles (one of the possible solutions) with high-speed experience a lot of drag. I can imagine them losing their speed (and thus penetration) and their trajectory and stability really fast. If you look at the taofledermaus videos you'll see that they are shooting at targets that are really close range and I will bet you that the slugs are extremely inaccurate and ineffective beyond the first couple of meters That said, there is a similar thing to your design already in existence. It is not a shotgun, but a 20mm grenade launcher. # Inkunzi PAW aka Neopup - 20mm Direct-Fire Grenade Launcher [![Inkunzi PAW aka Neopup - 20mm Direct-Fire Grenade Launcher](https://i.stack.imgur.com/GW8HF.jpg)](https://i.stack.imgur.com/GW8HF.jpg) It is a 20mm grenade launcher (fires 20MM VULCAN CANNON ammunition) made for disabling armored cars stuffed with explosives attacking checkpoints. It solves the problem of recoil with a hydraulic recoil system, shoots a variety of 20mm ammo, and is accurate to a couple of hundred meters without killing your wrist and shoulder in the process. It is a beast to carry, though. [FORGOTTEN WEAPONS YOUTUBE VIDEO ON THE THING](https://www.youtube.com/watch?v=QHbqHx3TLBE) # "Double Deuce" 2-Bore Rifle: A Gunsmithing Spectacle [![Forgotten weapons - "Double Deuce" 2-Bore Rifle: A Gunsmithing Spectacle](https://i.stack.imgur.com/Q0Vx5.jpg)](https://i.stack.imgur.com/Q0Vx5.jpg) The original idea you thought about already exists and has a very limited field of use and penetration. The guns are called stopping rifles and are used for wild game hunting, where you need to stop a charging rhino or elephant. (or T-REX if it's in the movies) The problem is the enormous weight, size, and recoil of the thing makes it almost unusable. [FORGOTTEN WEAPONS YOUTUBE VIDEO ON THE THING](https://www.youtube.com/watch?v=OYlDgwo52tI) # UNDER-BARREL GRENADE LAUNCHER Another thing to remember is usability. If your force is mainly using normal shotgun rounds, engineering a shotgun that will be much heavier or more mechanically complex to fire a penetrator once in a while is uneconomical and unergonomical. You're making the shotgun too heavy/complex for too little benefit. * If the modus operandi is to fire armor-piercing/explosive (concussion kills though armor) projectiles all the time/most of the time, you're better off with either a rifle (that fires smaller projectiles, but is easier and cheaper and lighter) or a grenade launcher/20mm cannon like inkunzi * if you're only firing grenades infrequently, it's easier and much more ergonomic, economic, and useful (because of payload size) to give the weapon an under-barrel grenade launcher --- ]
[Question] [ This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. I've been trying to imagine a convenient future airlock for people on planets with little atmosphere (which is most of the bodies in the inner and outer solar system). It feels like waiting 15-to-30 minutes each time you have to ingress or egress is a subtle, but substantial, pain. [Utility Fog](https://en.wikipedia.org/wiki/Utility_fog#cite_note-1), sometimes also called gray goo, is a metallic mesh made up of tiny (100 $\mu m$) grain-of-pollen shapes robots with multiple telescoping interlocking small arms. The robots as a network can change density and shape by telescoping arms in or out and letting go to grab a new partner. It was originally envisioned as a high-tech alternative to air bags. My thought was that a super-fast airlock could do this during ingress : 1. An extremely dense (minimal micropore) layer of utility fog forms just inside the inside door 2. The utility fog expands, kind of like the gas inside of a piston, to fill the entire compartment. 3. The super-dense region of utility fog moves like the piston of an engine from the inside door to the outside door, automatically adjusting its shape to allow the people and objects to pass through and pressing no harder on surfaces than 1 atmosphere. 4. The inner door, which was vented, allows interior air to fill the gap behind the utility fog. An entire airlock full of users passes through in seconds. [![enter image description here](https://i.stack.imgur.com/RLIw8.png)](https://i.stack.imgur.com/RLIw8.png) Is this feasible? Anything really important that I'm overlooking? Some Assumptions- * Best practices allow standardization between suit and habitat pressure. * Future technology allows semi-rigid suits that do not need to be over pressurized prior to opening the airlock * This question is focused at negligible atmosphere environments, and retaining most (not necessarily even all) of the hab atmosphere. Keeping toxic gasses out is not a concern. * Dust and other contaminants are taken care of by another system, or not taken care of at all. [Answer] You don't have airlocks at all, your vehicles and things are normally outside, and left outside (in the equivalent of a shed), and your pressurized suits are attached to the outside wall of your base, waiting for your staff to climb into them, then the space is sealed behind them. This is called a [suitport](https://en.wikipedia.org/wiki/Suitport). [![enter image description here](https://i.stack.imgur.com/2Z81A.jpg)](https://i.stack.imgur.com/2Z81A.jpg) The only use for an airlock is a life-or-death emergency, in which case you can do an emergency repressurization for the disabled crewmember (hopefully still in a standard pressure pressurized suit, otherwise they have bigger problems than the bends already), while any other crew can go back into the base the normal way via the suitport. [Answer] It's not a mechanical problem Your premise is that conventional airlocks take 15 - 30 minutes, and that's fairly normal. [Official documents](http://www.spaceref.com/iss/ops/7A.EVA.checklist.pdf) (pg 101) mandate 30 minutes for the depressurisation operation after a 45min pre-breathing session, though they don't actually say how long the process physically takes to decompress the airlock. The emergency procedure for quickly repressurising (pg 385) leads straight into treatment for the bends though, and some digging online suggests a crash-repressurisation period of only 45 seconds. I really wouldn't want to be required to do it! The upshot is that going from 1-bar to 0 in seconds is really really bad for human biology and your utility-fog approach in no way would protect users from decompression-sickness. [Answer] My first thought is that you are grossly overlooking [decompression sickness](https://en.wikipedia.org/wiki/Decompression_sickness) > > Decompression sickness (DCS; also known as divers' disease, the bends, aerobullosis, or caisson disease) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurization. DCS most commonly refers to problems arising from underwater diving decompression (i.e., during ascent), but may be experienced in other depressurization events such as emerging from a caisson, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness. > > > > > The original name for DCS was "caisson disease". This term was introduced in the 19th century, when caissons under pressure were used to keep water from flooding large engineering excavations below the water table, such as bridge supports and tunnels. Workers spending time in high ambient pressure conditions are at risk when they return to the lower pressure outside the caisson if the pressure is not reduced slowly. DCS was a major factor during construction of Eads Bridge, when 15 workers died from what was then a mysterious illness, and later during construction of the Brooklyn Bridge, where it incapacitated the project leader Washington Roebling. > > > > > Altitude DCS became a problem in the 1930s with the development of high-altitude balloon and aircraft flights but not as great a problem as AMS, which drove the development of pressurized cabins, which coincidentally controlled DCS. Commercial aircraft are now required to maintain the cabin at or below a pressure altitude of 2,400 m (7,900 ft.) even when flying above 12,000 m (39,000 ft.). > > > > > Generally, the higher the altitude the greater the risk of altitude DCS but there is no specific, maximum, safe altitude below which it never occurs. There are very few symptoms at or below 5,500 m > > > By quickly letting people out of the high pressure environment you are basically setting them up for getting DCS. And I guess the sudden change in pressure won't do any good to boxes and sealed container, either. When I worked with a glove box one of the first things that was taught was to be gentle with changing the pressure in the airlock when transferring samples. [Answer] Since you are assuming that the suits share the same air pressure as the habitation environment, then Arthur C Clarke had one solution: The Kwiklock. It's a spacesuit-sized, spacesuit-shaped airlock for large numbers of spacewalking shift workers building the first spinning-wheel space stations. He wrote about it in his conquest-of-space stories in the late 1940s/early 1950s. Since there little empty volume when occupied, it minimizes the gas lost to space upon exit, and requires very little additional air upon entry. Each user takes only a few seconds to pass through. [Answer] > > It feels like waiting 15-to-30 minutes each time you have to ingress or egress is a subtle, but substantial, pain. > > > I think you're underestimating the amount of work that goes into working with hazardous environments, and the risk of dumping someone rapidly into that hazardous environment. My related experience is with scuba diving. (I'm not very experienced, but hey.) It takes some time to kit up. Once you're kitted up, you cross-check your buddy's kit. You check all your gear works correctly. You keep checking stuff as you descend, and you check that your buddy is OK. Progressively pumping out air allows you to keep checking that your kit has pressure integrity as the pressure drops. An unobservable leak at 0.1atm differential will be a lot more observable at 0.5atm! You really don't want to rush this process, because it's literally the difference between life and death. The suits also may not operate at 1atm. A lower pressure will still be breathable and reduce load on seals. If that's the case, there's also a decompression time involved which can't be skipped. As for the time, [NASA says that it takes 45 minutes to put on a space suit](https://www.nasa.gov/audience/foreducators/spacesuits/facts/index.html). Another 15 minutes to carry out checks as you decompress the airlock is perfectly reasonable in the context of it already having taken you that long. I also foresee a major problem with the structural integrity of the suit with your [Maxwell's demon](https://en.wikipedia.org/wiki/Maxwell%27s_demon) barrier. Pressure suits are designed to have equal pressure all around them. Sweeping this barrier over the suit will give you a 1atm pressure differential on some parts of the suit and no pressure differential on other parts, making it balloon out. Normally it wouldn't be a problem because equal pressure everywhere makes the suit push out equally all round; but the barrier will give you point (or line) forces which aren't going to do it any good at all. Seals are also going to have problems when there's a pressure differential on one part and not on others. In reality anyway, the time problem is only with egress and not ingress. The outer door will be closed during their time outside (for safety), but the airlock will remain evacuated. When they come back in, the airlock can be filled with air as fast as you like. The part that's slow is pumping the air out, not letting it back in again. Of course any place like this will have multiple airlocks, and there will be a cast-iron rule that as long as there are people outside, there are always enough airlocks to process them. [Answer] Airlocks can work must faster. The problem isn't the lock... it's the people. Our bodies need more time to adjust, or we get [the bends](https://www.emedicinehealth.com/decompression_syndromes_the_bends/symptom.htm). <https://www.youtube.com/watch?v=ter7pAZF_nY&t=85s> <Warning: graphic video> One solution: build the pressure adjustment into the space suits. We can do this now, but the suits are more like the old deep sea dive system. For your imagined world, you can allow that technology to advance for things to be more comfortable, flexible, and lighter. If you really want the small bots, perhaps you can use them inside the suit to handle internal pressure. People put the suits on before leaving through the air lock. They set the suits to start depressurizing and then go outside immediately. The suit maintains the needed pressure, but also slowly and safely adjusts for the lower pressure in the new environment. When they ingress, people pass through the air lock again right away, as quickly as the lock is able to function, but they must leave their suit on. Instead of waiting in the lock, they set the suit to re-pressurize. You can normalize seeing people moving about a station or building while still in a suit, not to provide breathing air but to adjust for the pressure from when they were outside. Then the suit beeps at them and sets a status light when it's safe to remove. [Answer] It sounds like your main goal is to imagine a world where leaving or entering the hab is as easy as opening the door to your house, and you're willing to jump wholly into the realm of nanobots/grey goo in order to make that happen... So why not just do away with the whole conventional airlock business entirely, and instead construct a "door" out of nanobots where, as you walk through it, the bots wrap themselves around your body, preserving atmospheric pressure and providing mechanical counterpressure? Think about something like [exocytosis](https://en.wikipedia.org/wiki/Exocytosis)! I would think that, if the nanobots are technically sophisticated enough to meet all of the criteria you mentioned in your question, that they'd also be easily capable of linking together to form a "smart fabric" which reacts flexibly to user movements while maintaining the desired level of counterpressure. They don't necessarily need to be 100% airtight; if the colony has sufficient resources, they could tolerate a little leakage here and there. You could imagine that people would need to grab a helmet and a backpack/PLSS off the shelf before they walk through this gooey portal, and that the nanobots simply serve as suit material, or you could go full-scale handwavium and have them automatically construct a full suit with transparent visor and mechanicals by the time the person has passed through the door. In either case, the person would simply need to walk back through the other direction to "doff" their suit and get back to whatever they need to be doing. [Answer] Try Plasma Windows (or in this case Doors) instead. [Plasma window - wikipedia](https://en.wikipedia.org/wiki/Plasma_window) [![enter image description here](https://i.stack.imgur.com/M90hf.png)](https://i.stack.imgur.com/M90hf.png) The technology would need to be refined of course but in a future SF setting with plenty of power available. Edit; In principal however what would be created is barrier that would hold in the atmosphere (or most of it) but be permeable to physical objects like space suits. The suits would have to be non-conductive (I think) and communication aerials etc insulated/inactive while passing through the plasma stream but that's just a turn off/turn on issue for the user - no comms while passing through the plasma. Ideally you'd still have an airlock with two physical hatchways (inner and outer) but the exit procedure would be simple; 1. Enter airlock and close hatch (precautionary). 2. Activate outer hatch controls (which automatically activates the plasma window across the exit hatchway at the same time.) 3. Open outer hatch/exit the station or vessel while the plasma field contains the atmosphere. Close hatch - automatically switching off the plasma window. Reverse procedure on return. You might consider reducing air pressure in the airlock (again as a precaution against an emergency 'blow outs' but you wouldn't have to go to vacuum. The other cool thing (I think anyway) is that you could put these systems throughout a station or ship . So if a disaster depressurizes one or a series of compartments emergency power could give you permeable airlocks across any doorway they were fitted to that would activate automatically and instantly. Provided you have power of course. [Answer] There are two reasons the airlocks at ISS take so long: 1. The internal atmosphere has approximately normal composition and pressure corresponding sea level pressure while the EVA suits have pure oxygen at just enough pressure to be safely breathable, because that's what you actually need and any extra inert gasses would just inflate it like a ball and make it harder to move in. However, body needs some time to release all that nitrogen. It is not much of a problem for recompression. 2. There is a whole lot other tasks to accomplish to ensure everything is working, because their lives depend on it. But you don't really need the nitrogen. Apollo had pure oxygen throughout the flight. The discussion [on space](https://space.stackexchange.com/questions/5690/) suggests that the main reasond for using Earth-like atmosphere are simpler take-off and landing—the transition from normal atmosphere to the pure oxygen is tricky and you can't just use pure oxygen before take-off, because you'd just burn like Apollo 1—and possibly cooling. So when designing a permanent base on another body with little atmosphere, those reasons don't really apply. So have an oxygen-rich atmosphere in the station, use the same in the extra-station activity suits, and you can pressurize and depressurize the airlocks in a couple of seconds with no ill effects, because the pressure inside the suits won't be changing at all. ]
[Question] [ A kind of soldiers in my world can use certain magical equipment to launch themselves into the air and stay airborne (sort of like gliders. They need to keep moving ahead; they can't hover much). Note that they need to keep their hands free whenever possible; they use magical gloves on their hands (and feet, but they're not very useful once airborne) as sort of close range grappling hooks cum vacuum pads which can be used to propel them at no damage to themselves due to the magic (but a lot of damage to whatever they used to propel themselves) While there are many ways I've thought of in which they use throwing knives, lances, swords etc. while airborne, is it possible to use bows or crossbows? 1. Is it possible to draw a bow midair? If not, then they would use crossbows that they would load while on the ground and shoot once midair. 2. Once the arrow is released, how would conservation of momentum affect them? If they shot in front, it would send them flying back, or at least slow down their forward movement a lot, maybe forcing them to get down to where they can use the ground to propel themselves. If they released it downwards, while flying above the enemy, would it propel them upwards? Does an arrow have enough momentum to do any of these? Is this even effective at all? Or would it be better to give these archers closer range weapons and send them into the fray? Because these are some elite military units, used for some of the most difficult tasks or for stuff like horseback chases. So would it even make sense to train some of them for ranged combat? [Answer] ### Yes you can, and a subtle effect. Rather than getting all physics on you, I'd suggest the best way to understand this is to try it: hop on a skate board / roller skates / frozen lake / floor covered with lube, put on some safety gear like helmet, and give this a shot, the physics are the same. (It's both fun and educational!). 1. Assuming you're able to fly with your hands and arms free enough, then yes, you can draw a bow while airborne. * At the risk of my technique being ripped into by the expert archers, basically you're pushing the bow with one hand and pulling the string with the other, and the difference between those forces will draw the bow by deforming it. There will be no net acceleration on you when you do this assuming your travelling at safe speeds (eg <100km/h) and wind drag isnt that much of an issue. 2. There will be subtle [recoil acceleration](https://en.wikipedia.org/wiki/Recoil) from releasing the bow. Not enough to knock you out of the sky. * This is known as conservation of momentum. * Assuming 100kg flyer, 10g arrow, and 100m/s (360km/h) launch speed. Your arrow will impart 1kgm/s of backwards momentum (10g \* 100m/s), you will decelerate by 0.01m/s (0.036km/h) 1kgm/s / 100kg. * If you were travelling at 10m/s (36km/h), you'd need to fire ~1000 arrows before you come to a complete standstill. [Answer] Drawing a bow midair doesn't look impossible, and seems way more practical than bringing loaded crossbows along. Due to practical limitations, how many crossbows could one take along? 5 seems to be already a large number, and a flying attacker firing up to 5 darts before stopping seems rather underpowered. Also recoil doesn't seem to be a huge issue: first of all the departure speed of an arrow is way lower than the bullet coming out of a gun/rifle, and so is its mass. If you take an arrow leaving the bow at 100 m/s (which is about the fastest arrow a composite bow can launch) and with a mass of about 50 grams, it would rob an archer weighing 70 kg of just $100 \cdot 0.05 \over 70 $$=0.07 \ m/s$ of velocity. The above follows from the conservation of momentum $m\_1 \Delta v\_1 = m\_2\Delta v\_2$ [Answer] [Lars Andersen](https://www.outdoorhub.com/stories/2015/01/23/lars-andersen-fastest-archer-world-back-new-video/) can catch an arrow shot at him and accurately return fire while still in the air. It is by no means impossible to shoot a bow while in the air. Conservation of momentum means that the momentum of your projectile will be subtracted from the momentum of your archer once it is fired, according to the law. A heavy arrow might weigh as many as 40 grams (600 grain), and could be shot as fast as 150 kph. The total momentum would be 0.600 kg\km/h. You then divide that momentum by the mass of your archer in kilograms, and that is how much they have slowed down. A 50 kg archer would be slowed down by 0.012 km/h, or would have to shoot about 83 arrows to be slowed by 1 km/h. I would expect the tactics used to be similar to and just as effective as Mongol horse archery. [Answer] Throwing and drawing a bow require a remarkable amount of core and upper body movement. Throwing specifically is the art of transferring the momentum of your body into another smaller object. I have some practical experiments for you. Throw a ball normally to judge your range. Throw a ball while sitting down. Throw a ball with your back to a wall. Now consider that required body movement, the body movement for drawing a bow is similar to that of winding up a throw, and how your soldiers control their gliders and their body position while using the glider. Consider along with this the way an arrow lies on a bow, it's not constrained by much other than gravity. Which side it lies on depends on the type of bow they use and the style of release (normally left side for right handed). This will give you the practical angles at which a bow could be fired effectively while using the glider, however throwing while gliding likely lacks the body control and stability required for significant power transfer and you'll be better of dropping objects from height rather than attempting to throw anything. [Answer] > > Is it possible to draw a bow midair? If not, then they would use crossbows that they would load while on the ground and shoot once midair. > > > I went to a martial arts school with an archery range. One of the things the instructors had us do for us to learn how to shoot fast was leaping over a bench or a chair (while running) - and we had the time in the air to aim and shoot. Most of us did start the jump with the arrow already nocked, but some of my most graduated colleagues managed to nock the arrow mid-jump. For conservation of momentum, see the other answers for the math. But for simplicity, many archery range targets are lighter than an adult and are not knocked down by the arrows that hit and get stuck on them. An arrow won't change an adult's momentum much. [Answer] All these answers are neglecting the boring realities of the effects of these archers on "real combat". There are two aspects to a projectile's range and terminal velocity: Initial launch speed * Initial altitude Fighter jet pilots know this well - the main complaint about the F-35 is that it will launch a missile from lower altitude and with less velocity than its competitors, therefore the enemy will "dump on it" and get out before the F-35 can respond. You have a similar situation - your magic archers will impart forward velocity just before firing, and they will do so from altitude. The result? Terminal velocity on impact, from outside of the enemy's engagement envelope. Basically, you just invented an undefeatable force, for conventional armies. Invest in big shields and SOF\* to attack re-supply stations and ambush resting archers. With all that said, do you really need "archers"? What keeps you from having flying dudes who just toss bags filled with pointy rocks from altitude? Put them on a disk that spins and throws them in random directions at x altitude via spring. You basically just invented medieval air burst munitions. Your "archers" aren't going to be firing at point targets anyway. Oh, and say goodbye to normal fortifications. Have fun with this rabbit hole, it never ends. Edit based on reply: In that case, the "real world" application is signaling. Look up "indirect fire grids", "designated kill zones", etc. The really simple version of this is that the commander pre-defines squares within range of his artillery, kind of like on a chess board. Your "archers" fly around and look if the enemy is advancing on any of these squares, and then give a signal to your catapults for indirect fire on these positions. Anyway, this is only if you want to get fancy with "practical applications. You could have them zooming around and firing on generals / mages / whatever. Probably in low-visibility conditions - at night, in fog, etc. \*Special Operations Forces [Answer] Why bother with bows and arrows at all? They could just drop or throw air-based [flechettes](https://en.wikipedia.org/wiki/Flechette). [![enter image description here](https://i.stack.imgur.com/BzdIz.jpg)](https://i.stack.imgur.com/BzdIz.jpg) The flechettes have a higher terminal velocity than arrows and gain kinetic energy as they drop. Also, flechettes (as well as arrows) benefit from the initial velocity of the weapons platform. A two-inch long version of these weighing only 0.7 ounces called the [Lazy Dog](https://en.wikipedia.org/wiki/Lazy_Dog_(bomb)) was used to devastating effect in Vietnam and > > could be hurled from buckets, dropped by hand, or thrown in their small > shipping bags made of paper > > > [![enter image description here](https://i.stack.imgur.com/ZSncn.jpg)](https://i.stack.imgur.com/ZSncn.jpg) A satchel of these bad boys would allow a flying human to devastate ground troops. [Answer] It strikes me as slightly odd that you are worrying about real physics when you've already got the archers doing 'flying by magic'... why worry about conservation of momentum or the like in this circumstance? You could just define that they are able to operate whatever weapon and that it has no effect on their velocity or height as it's compensated for by the magic. On a more real physics not, drawing a bow / crossbow requires the archer to act against their own body to store energy in the bowspring. From a physics point of view, it's all in the archer's frame of reference so what the archer is doing in an external reference frame shouldn't matter... up to the point they loose or launch or let fly. ]
[Question] [ In the story I am developing, there is an intergalactic community with a plethora of different sentient species, each with its own languages that vary depending own its vocal anatomy. There are universal translator implants that act as a brain-brain interface and allow all kinds of beings to communicate because a lingua franca would be limited to only the phonemes present in every known phonetic table from all species, which is none. Since I decided that each character will speak their own created language, I decided that I would create a phonetic table for all physically possible phonemes for all vocal anatomies in this universe, that will also work as a universal alphabet for transcribing speech. I just need to know if this is feasible. I thought about researching animal sounds, but I didn't find any kind of table for animal sounds, as it's not a thing that sparks scientific interest or is of any utility. Do you know of any means through which I could achieve this? [Answer] Given that your interplanetary "phonetics" may not just include speech, but also scent/pheromones, physical gestures, or patches of skin that light up/change colour, your plan to make a universal set of phonemes is doomed either to failure, or to limit the types of aliens your world contains. A better suggestion would be to crib an idea from an old Chinese emperor: in short, China had multiple spoken languages, but one official written language. The symbol for a word ‚Äî such as "food", or "house" ‚Äî would be the same wherever you were, but how you read or pronounced it would differ depending on what region you lived in. Even today, you see the same thing with some aspects of Mandarin and Cantonese. So, you will have a single written language (which might be ideographic, or might be phonetic), you will have multiple "spoken" languages, eachc compatible with a different subset of species. Earth languages have between 13 (Hawaiian) and 48 (Nemi and Norman) phonomes. So, for the sake of neatness, let's assume your written language has 50 "phonome" symbols, which can be arranged to form any and every word. Some species will use phonomes that sound very similar to Earth languages. Some species will use insect-like chirps and clicks. Other species will produce a deep bass whalesong. Or specific colours. And so on. So long as you know that the symbol you know as "Sh" in mammellian is the same one called "Krr'tlik" in insectile, "Vrrooon" in rumblese or üüß in chameleoid, and ü§è in gesturoid, you ‚Äî or your Universal Translator ‚Äî can easily translate it, via the written form. Similarly, you will all understand the meaning of the three symbols making a sign on the wall in the gym, whether you say it as "üüß-üü´-üü™", "Vrrooon-Hmmgh-Earp", or "Sh-ow-er". [Answer] Frame challenge: you are giving yourself a lot of unnecessary work. Your implanted translators mean that your readers or players don't need to know the details of your languages' phonetics. That table of phonemes only works for spoken languages, and does not help at all for signalling with gestures, colour changes, scent, or radio. All of those methods could plausibly be used by aliens. Unskilled attempts at constructed linguistics are fairly pointless. They make you look silly to people who know linguistics, and don't usually impress people who don't know about languages. [Answer] The [International Phonetic Alphabet](https://en.wikipedia.org/wiki/International_Phonetic_Alphabet) is used to describe sounds present in human languages. It is organised by place and manner of articulation in the vocal tract. I.e. the sound [p] is a bilabial voiceless stop, meaning it is made using both lips, the vocal cords are not vibrating, and as a stop the lips fully touch stopping the airflow entirely before releasing it again. All this organisation is only possible because we have a good understanding on the human vocal tract. Similar tables could be constructed for any given phonetic system, but a system that aims to include all possible vocal tracts would have to be so large as to be completely unusable. The only way to objectively represent the sounds produced by an arbitrary vocal tract in a way that isn't incredibly unwieldy would be to use a [spectrogram](https://en.wikipedia.org/wiki/Spectrogram). The fact that language need not be based on sound at all makes it even less plausible. Even dealing solely with human sign languages the array of possible handshapes, locations, movements, and other gestures is so vast that no equivalent of the IPA (that can meaningfully distinguish any two signs distinguished in any sign language) has been constructed, and even transcriptions dedicated to one specific sign language are difficult or impossible to interpret without detailed knowledge of the language in advance (making them more like English spelling than a phonetic alphabet). If your aliens have drastically different body plans, encoding their sign languages would make it even more complicated. Other modes of communication e.g. using chromatophores, radio, scent, etc will fall somewhere between these extremes (one where it's practical to transcribe within a given species but not across all possible species without just giving the raw sensory data received by the "listener", and one where even phonetic transcription of a single language is impractical). So wanting to also include all modes of communication would make the implausible utterly impossible. Your best bet is to avoid attempting phonetic transcription entirely. In general I would recommend simply translating the speech of aliens, with some note as to the language and mode of communication, especially when the language is not based on sound. Where quoting verbatim is absolutely necessary (e.g. for proper nouns, words with no equivalent in human language, and potentially poetry being recited) I would give the text in the alien language, either followed immediately by a translation, or in a context that makes it unambiguously clear what the meaning is. Note that this is the approach Tolkien (the father of constructed languages in fiction) takes and even then some readers find the amount of his languages he includes off-putting so attempting to include more is almost certain to backfire. When you do quote alien speech verbatim, I would rely on an ad-hoc transcription. You should not attempt to include all the phonetic detail of the aliens' actual speech, but instead give an impressionistic understanding of how your audience would describe the sounds. Your aliens may have very different vocal tracts, but if they have a sound (or multiple sounds) that sound similar to a [p], just write them as "p". I would avoid using diacritics (accent marks) or apostrophes as these tend to make (English-speaking) readers more conscious of the artificiality of what they're reading (even though of course these are used in various languages to denote specific sounds). Your ad-hoc transcription should probably reflect those used historically by English-speakers to write words in foreign languages. These typically use vowel letters similarly to their use in Spanish or Italian, use consonants in their usual English sense, and generally avoid c in favour of either k or s. Sounds not present in English should generally be transcribed according to the closest sounding English sound (or combination of sounds), although certain foreign sounds do have fairly common transcriptions (e.g. the German "ch" sound, the same as the Spanish "j" sound, or Russian "—Ö" sound is usually transcribed ad-hoc as either "kh" or "ch", although the latter may be confused with the English "ch" sound [tÕ° É]). As an example, this is article 1 of the Universal Declaration of Human Rights in Hindi, first written in the native script, then in an ad-hoc transcription as I would write it if it were an alien language in a novel, in a scientific romanisation you'd see in a grammar of Hindi, and lastly in the IPA: * ‡§Ö‡§®‡•Å‡§ö‡•ç‡§õ‡•á‡§¶ 1(‡§è‡§ï): ‡§∏‡§≠‡•Ä ‡§Æ‡§®‡•Å‡§∑‡•ç‡§Ø ‡§ú‡§®‡•ç‡§Æ ‡§∏‡•á ‡§∏‡•ç‡§µ‡§§‡§Ç‡§§‡•ç‡§∞ ‡§î‡§∞ ‡§Æ‡§∞‡•ç‡§Ø‡§æ‡§¶‡§æ ‡§î‡§∞ ‡§Ö‡§ß‡§ø‡§ï‡§æ‡§∞‡•ã‡§Ç ‡§Æ‡•á‡§Ç ‡§∏‡§Æ‡§æ‡§® ‡§π‡•ã‡§§‡•á ‡§π‡•à‡§Ç‡•§ ‡§µ‡•á ‡§§‡§∞‡•ç‡§ï ‡§î‡§∞ ‡§µ‡§ø‡§µ‡•á‡§ï ‡§∏‡•á ‡§∏‡§Ç‡§™‡§®‡•ç‡§® ‡§π‡•à‡§Ç ‡§§‡§•‡§æ ‡§â‡§®‡•ç‡§π‡•á‡§Ç ‡§≠‡•ç‡§∞‡§æ‡§§‡•É‡§§‡•ç‡§µ ‡§ï‡•Ä ‡§≠‡§æ‡§µ‡§®‡§æ ‡§∏‡•á ‡§™‡§∞‡§∏‡•ç‡§™‡§∞ ‡§ï‡•á ‡§™‡•ç‡§∞‡§§‡§ø ‡§ï‡§æ‡§∞‡•ç‡§Ø ‡§ï‡§∞‡§®‡§æ ‡§ö‡§æ‡§π‡§ø‡§è‡•§ * Anuched 1 (ek): Sabhi manushya janma se svetantra or meryada or adhikaro me saman hote heng. Ve terk or vivek se sampana heng tatha unhe bhratritva ki bhavena se perasper ke prati karya kerna chahie. * Anucchƒìd 1 (ƒìk): Sabhƒ´ manu·π£ya janma sƒì svatantra aur maryƒÅdƒÅ aur adhikƒÅr≈çÃÉ mƒìÃÉ samƒÅn h≈çtƒì haƒ©. Vƒì tark aur vivƒìk sƒì sampanna haƒ© tathƒÅ unhƒìÃÉ bhrƒÅtrÃ•tva kƒ´ bhƒÅvanƒÅ sƒì paraspar kƒì pratƒ´ kƒÅrya karnƒÅ cƒÅhiƒì. * […ôn ätÀê É ∞eÀêd eÀêk \| s…ôb ∞iÀê m…ôn ä Çj…ô d í…ônm…ô seÀê s ã…ôtÃ™…ôntÃ™…æ…ô …îÀê…æ m…ô…æjaÀêdÃ™aÀê …îÀê…æ …ôdÃ™ ∞…™kaÀê…æ√µÀê m·∫ΩÀê s…ômaÀên hoÀêteÀê h…õÃÉÀê‚Äñ ãeÀê tÃ™…ô…æk …îÀê…æ ã…™ ãeÀêk seÀê s…ômp…ônÀê…ô h…õÃÉÀê tÃ™…ôt ∞aÀê än ∞·∫ΩÀê b ∞…æaÀêt…æ…™tÃ™ ã…ô kiÀê b ∞aÀê ã…ônaÀê seÀê p…ô…æ…ôsp…ô…æ keÀê p…æ…ôtÃ™iÀê kaÀê…æj…ô k…ô…ænaÀê t ÉaÀêh…™eÀê‚Äñ] I would be extremely hesitant to attempt to transcribe any language based on a medium other than sound. Rather than describing a sign or pattern of lights etc, you're almost always going to be better off relying on the best translation you can give (together with a note that they are communicating through signs or lights etc), even for proper names and words with no clear equivalent in English, as descriptions of these are likely to get overly cumbersome and draw a reader out of the story. If you want to show off your conlanging beyond this, I would suggest doing as Tolkien did and leaving it for the appendices. [Answer] Humans have "International Phonetic Alphabet". So wouldn't be surprising if a larger civilization had one (or several) as well. Likely they would need to modify it with human phonemes. ## Create it without detail / handwave > > As we were learning their language the <alien people> we noticed their dictionary had additional symbols after each entry word. Upon asking they showed us some copy of "intergalactic community phonetic alphabet". > > > That is all that is really needed in terms of creation. Just a description that it exits. With at some point some additional story indicating how that affects the characters meaningfully. In this case perhaps how the main characters were able to pass this information on to their linguists to map human phonemes to the alien ones for use in automated translators. [Answer] ## Expanded IPA Nobody knows all the vocal anatomies in your universe. Someone from a virgin planet might assume there are an infinite variety; but your question implies this is not the case. Still, someone made the table. So we'll assume it's someone from Earth. They started with the standard IPA characters. Then they added two more characters to each and every IPA symbol, massively increasing the diversity, and shoehorning almost every alien sound into this system. Result: you start with some goofy IPA symbol, like üÃù, and then modify it up into a Hangul-like symbol, like Ìïú. Note that you have simplified and stylized the character on the right a bit, to look spiffier on the side of an interstellar freighter, and easier for pirates to read. Most folks in Korea could probably help out with this. You've also gone from merely designating the sound as a "dorsal velar lateral fricative", to designating how many spiracles and throats are involved, whether they beamshape the sound with phase-controlled interference, and whether there are any associated bodily fluids encoding a simultaneous meaning. The good news is that there are hundreds of billions of planets in the Galaxy, many of them inhabited. Among all those worlds, there might be a billion individuals who feel comfortable writing in IPA, and at least several dozen capable of handling its full expansion to alien language systems around the galaxy, provided they have suitable reference works to consult. [Answer] ## There can be not be an interspecies phonetic alphabet The reason for this is that not all alphabets are phonetic. Let's take this alphabet here: [![enter image description here](https://i.stack.imgur.com/5EGCF.png)](https://i.stack.imgur.com/5EGCF.png) Much like the phonetic alphabet, this one is designed to be able to compose any word you like from these symbols. It can work for a lot of different languages... as long as it is a language spoken with your hands. Does not matter if you speak ASL or LSA, you can represent nearly any hand sign using this alphabet. But because Sign Languages and Phonetic Languages are compiled from different communication mechanisms, there is a 0% overlap between where these alphabets could be used. At most you could have a character set much like UTF where a computer can store a lot of different character sets from different languages into a single text string; so, you could have something like this with hand-sign characters tacked in too. You could even add in characters for different light, electrical or smell patterns that other species may use to communicate. Also, some aliens may be blind. In the the Voyage of the Space Bubble series, there was a neat alien race that could only see via echo location so they were completely blind to written text and 2-dimentional imagery. [![enter image description here](https://i.stack.imgur.com/hbq6U.png)](https://i.stack.imgur.com/hbq6U.png) Ultimately though, just using the same character set is not enough because even though UTF may allow me to write a the symbol from the Arvekian Smellabet which stands for the smell of something rancid, it does not mean that an English speaker would ever know what that symbol means, much less have the ability to communicate by stringing together a series of smells. ## ... the good news is that it does not matter. Translation and image recognition software is is already good enough to make this a non-issue. Instead of worrying about needing an IPA for all species, you just need an expand your idea of what an interspecies translator can do. I will never need to know the characters of the Unified Interstellar Smellabet because when I do need to read Arvekian signage, I will just need the neural implant to interface with my optic nerves to translate what I am seeing as well as hearing. [![enter image description here](https://i.stack.imgur.com/BnMrj.png)](https://i.stack.imgur.com/BnMrj.png) [Answer] The IPA is at best marginally a system for all human languages. English and French work mostly fine, but you start transcribing Irish you'll note that Irish has pÀ†, p ≤, bÀ† and b ≤. Ju«Ä ºhoan distinguishes between b, p, p ∞ and bÕ°p ∞. With enough symbols, IPA can get all these details, but it's clearly biased towards the major Western European languages. When you take very careful look at English and French, you'll realize that English t is usually dental and French t is usually denti-alveolar, slightly different sounds subsumed under one letter; some languages differentiate between both. I suspect the Japanese wouldn't have separate r and l letters if they had created IPA. For a known set of vocal and auditory equipment, IPA still has trouble with the number of slightly different sounds that distinguish words in some languages yet are used indistinguishably in other languages. The idea of making something for all the distinctions among all alien life with whatever range of vocal and auditory equipment strikes me as largely futile. Playing with it could be fun, but actually working all the details out is like providing the detailed schematics of FTL drive; pointless and glaringly unrealistic to some readers. [Answer] It is, I believe, impossible in theory to create a phonetic system that is both universal and useful. We have a universal system for transcribing any audible sounds today! In fact we have a few of them - MP3, .wav, .ogg, and pretty much any other audio recording format can represent any sound that any of your aliens can produce. It's difficult for humans to read those files directly, but it's easy to imagine a system of translating some audio format into symbols that can be read by eye. Somebody clever could work out a system where one kind of symbol lets you know the pitch, another lets you know the volume, and so on. A system like that probably wouldn't satisfy you, because it seems like those symbol-ized audio recordings would contain way more data than we actually need! Surely there has to be a way to strip out all the extra stuff, all the variations in speed, tone, voice quality, etc that don't actually affect the meaning? That's what phonemes really are - big groups of similar sounds where we have decided the differences don't matter and our language treats anything in the group as being "really the same" as anything else in the group. But you are looking for one single system that works for every type of hypothetical species out there in your entire universe! An individual language probably doesn't depend on most of those things. It would take a lot of brain power to even say a word in a language where the meaning could totally change based on how loud each letter is, exactly how high-pitched the vowels and voiced consonants are, how fast you're speaking them, exactly where your tongue is in your mouth, and so on. But the only unreasonable part of that is putting it all into the same language - there are human languages where the meaning of words legitimately does change based on each of those characteristics, and many more besides! The International Phonetic Alphabet already has a difficult time representing all the different aspects of human speech that can affect meaning. Not to mention finding a way to ignore the aspects that some languages care about but others don't! Imagine the difficulty of including all these other aliens! * Parrot-like aliens that are perfect at mimicking individual voices - a word said in your voice means something different than a word said in my voice. How do you write down which voice they're using? * A planet with multiple species of aliens that communicate through something like Morse code - it doesn't matter what sounds they make at all, the only thing that matters is how long the sound is and how much space there is between sounds. Do you need to write down whether they sound to you like "blah blah blah" or "hee hee hee"? * Aliens like Groot, who sound like they always say the exact same thing, but really all the meaning is in very subtle intonation differences. Will you be able to write down anything except "I am Groot"? At that point, you're probably better off using audio recordings for everything, and letting the speakers of the language decide which are the real phonemes and which are meaningless extras. [Answer] # Not with iconography, but maybe down-sampled waveforms Having actually attempted this, I can tell you that it's impossible due to the variations in noisemaker shape. Phonetics are broken down into two areas: consonants and vowels. Consonants can be characterized by what part of the mouth provides the primary surface for shaping the sound. For instance, M is done by the lips, N is done with the pallet, and NG is formed using the back of the mouth. Within that range, where would you categorize a cricket's chirp? The rasp of an angry tarantula? They bear no relationship to each other, so there's no way to map them to a single schema. You can invent separate characters for each of them, but if you don't know what the creaking of an Aluvian Thermobeast sounds like, then a symbol will do you no good. That said, what you could do is generate squiggles that mimic the wave form of the sounds. This is really down-sampling, and humans wouldn't have the ability to read such a scheme, even with practice, because it's too detailed. For more detail on how that might be accomplished, here is a good reference: <https://swphonetics.com/praat/tutorials/understanding-waveforms/speech-waveforms/> [Answer] > > I just need to know if this is feasible. > > > Not in a way that would be useful as a sort of "Universal Alphabet" to be slapped under signage like „Éû„ÇØ„Éâ„Éä„É´„Éâ (m…ôkÀàd…ën…ôld) for nonlocals to parse... though it is possible that there might be some "internal" phonetic coding scheme that the translator devices themselves transcribe inputs and outputs with (though that is likely unnecessary as well). --- The main problem is that, once we go universal, the goal of having a "Universal Phonetic Alphabet" - that is having some minimum viable character set that folks learn so that they can "spell out" anything they wish to convey to others - becomes unworkable due to the sheer variance of possible phonemes available to alien anatomies. The goal of IPA is basically to have a single character set that covers all input languages without having multiple characters overlap the same sounds. So, for example, the name of the Greek letter "Œì" is spelt out in English as "Gamma" using the Latin alphabet, and it is spelt out as "–ì–∞–º–º–∞" in Russian using the Cyrillic alphabet. Rather than adding both the Latin "G" and the Cyrillic "–ì" to the IPA character set - IPA decided that both sounds are equivalent and should use the same letter. So, great! IPA readers have one less character to learn. And if we continue that process, then rather than learning an entire 26-letter Latin alphabet and an entire 33-letter Cyrillic alphabet, we can learn a single distilled IPA alphabet that is maybe only 39-letters or so instead of the full 59-letters without overlap. Unfortunately, it is unlikely that this kind of character-space "savings" will continue significantly as we go universal. Clearly, if some species of squid-people speak using only their chromatophores, then there is going to be absolutely zero overlap between Earth-IPA and the Squid-IPA. So there is no benefit to learning the "Universal Phonetic Alphabet" over learning the two distinct languages outright, and the problem only gets worse as more and more species communications enter the fray. So, an UPA learner maybe only needs to learn 100,000 phoneme letters instead of the full 1,000,000 involved in learning each species individual alphabet! While, yes, that is a much smaller number, it is still completely impractical. --- Really, though, that isn't a problem if your future setting already has real-time translation devices capable of synthesizing the correct audio/visual outputs. Having these devices translate directly from Language-A to Language-B without first taking a detour through Language-UPA is perfectly reasonable. That being said, there are a few things that still may happen even if these technologies aren't crazy expensive. Firstly, there are likely to be a small number of languages that become dominant due to being the "language of business/commerce" - so it becomes very likely that signage will have the local language and then a translation in the most dominant trade language in the area. Secondly, there might be regions where two languages (and maybe a few more) happen to share a considerable phonetic overlap in which case a regional-UPA might actually make sense. ]
[Question] [ I'm working on a small story, and in it I'm wanting to include a city surrounded by multiple layers of walls. The walls themselves are colossal, but were created/held up by sorcery. I would go into more detail, but this question was about the city itself and not the walls. I'm looking at a size of roughly 2,000 square miles in total and a population density of 5,000 people per square miles with a late medieval/early renaissance level of technology (15th/16th century). Is this even possbible? Sorcery can't just summon resources in this setting, so that option isn't present. Humans make up most of the population, but the small other groups use roughly the same amount of resources. Theres also a magic system, of which I'll describe here. -Magic is a natural force, while sorcery is interacting with that force. -In order to cast any kind of spell, one must have the 'fuel' (the death of a sentient living thing), a mage to 'guide' the magic (or you get wild magic) and a target. Spells can take several days to do anything. Sorcery doesn't have a set range, but the further away the target it the better the chance of things going wrong. -Sorcery isn't something someone is born with. It's a skill, just like being a blacksmith. -Sorcery cannot create new matter, nor can it destroy matter. You can turn lead into gold, but you can't create coins from the air. -Wild magic is 'charged' magic without any target. It usually manifests as natural disasters, horrific disease, or simply a giant ball of invisible force that levels entire cities. [Answer] ## It is not realistic. Before the end of the medieval period, every city in history that exceeded 1 million people was at the center of an empire with a total population of at least 100 million people. Rome (200 AD), Kaifeng (1100 AD), Hangzhou (1300 AD), and Jinling (1400 AD) all belonged to nations with populations commonly estimated at 100 millionish people... and not all historians agree that these cities actually exceeded 1 million people. While it only takes 10 rural people to feed an urban person before modern farming was invented, the largest city of a nation with upwards of 100 million people almost never exceeds 10% of the nation's total urban population. But since we are trying to push the envelope here, if you cherry pick largest city size to smallest national population estimates instead of using averages or most accepted estimates, you could take the top estimate of the city of Rome at 1.2 million and the bottom estimate of the empire's total population of 59 million and arrive at Rome being 20% of the nation's urban population. Since your city would have about 10 million people, and your agriculture restricts you to a 10% urban population, this city logically must be the capitol of an empire with a population somewhere in the 500 million to 1 billion range... since the total human population of Earth did not reach 500 million until the Renaissance or 1 billion until 1803, it is inconceivable for a Late Medieval or Early Renaissance city to grow to 10 million people unless your really fudge for a highly idealized population distribution and it literally conquered the entire world. ... and this is before you even try to tackle the issues of sanitation and distribution. ## But what if you use magic? So sorcery can not just summon up resources out of thin air, but that does not mean it cant enable resource availability where it would not otherwise be... so maybe I am looking at this wrong. > > ...they can't get that without offering something living in return. Life is life... > > > Since it sounds like the OP is going for some manner of equivalent exchange magic system, perhaps you can trade something not alive for something else not alive that HELPS you create more life. You are looking at a population density of ~7.8 people per acre which means you can not grow enough food inside the city unless you drop the density down to about 1 person per 2 acres... but what if you could do vertical farming? Perhaps the city is actually several stories tall with 16 stories being in-door farmlands lit by magical lighting, and only the top 1-3 stories being actual homes, shops, etc. The trick to making this city work is a massive aqueduct system, something much grander than that of Rome, but since we've already established thier ability to make megastructures like the walls, this should be fine. The aqueducts could collect the water from an entire range of mountains, and this water would solve all of your problems. It gives you water to drink and irrigate your crops with. It gives you plumbing for solving your sanitation issues. Since water is a life sustaining inanimate substance, it should be like enough to light to make a fair equivalent exchange: water for light, to grow your underground crops. And lastly, in means you do not need massive amounts of people coming and going to supply the city; so, the walls will not chock off logistics preventing you from getting enough food where it is needed. The real trick here is not that you have a 10 million person urban population, but a 1 million person urban population supported by the 9 million rural workers who toil in the under-city farmlands. Place this city at the heart of an empire with a total population in the 100 million range and it all adds up. [Answer] Pre-modern cities in general needed massive amount of farmers working elsewhere. The safe calculation is that urban population can be only as big as 10% of total population, which mean that your 10mln man city would need 90mln people producing food. Now to put it into perspective, ancient Rome had around 1mln people and even though essentially entire Mediterranean sent food to Rome, famine and disease was common among the poor city dwellers. It was also plagued by crime as there was no proper crime fighting force established. Assuming that a medieval farming needed about 2 acres of land per person you would need 800 000 km2 of relatively good farmland assuming that there were no local urban centers consuming part of the food supply (which is not probable, those centres are necessary for administration). How much is that? Spain and Portugal combined is around 600 000 km2 and only a part is possible as farmland. Currently in EU farmland is about 39% of all land surface. Assuming in medieval system it will be less, say 25%, you would need some 3 200 000 km2 to feed your city, a combined land surface of Spain, Portugal, France, Italy, Germany, Sweden, Norway, UK and Poland. And you would need all those areas around an inland sea (or massive navigable river system) as transporting grain by sea is 40 times or more (depending on ships size) cheaper than transporting it on land, plus it would be difficult to govern over such large and populous area if there was no way to travel relatively quickly by water. [Answer] 5000 people per square mile on a surface of 2000 square miles makes 10 million people. With medieval level of technology those would be 10 million corpses: transporting enough food and water to feed them and taking rid of their wastes is something beyond medieval level. Famine or some lethal plague are granted. For a reference, London in the middle of 1500 had just 120000 people living there, and wasn't famous for being a clean city. Today London has a density of 7000 people per square mile. [Answer] As per the above. Food is the problem. Assuming you have a system of aqueducts, sewers and/or rivers feeding fresh water into the city and removing waste from the city you can probably 'solve' the water problem. But even then you have to assume waste disposal is solved by the application of rigorous public hygiene laws that weren't in place anywhere during the middle ages. And note: those laws only came into place during the 19th century in response to the discovery of disease theory. So you need your society to have far more advanced notions of medicine and public hygiene than were actually present during the middle ages. You will also have a humongous problem with horse shit! This remained a dire problem in large metropolitan centers until the invention of the internal combustion engine! In fact the first international conference on urban planning in 1868 was held to discuss methods of disposing of it! But that aside, the people will still starve. There is simply no way to grow enough food inside the city boundaries to feed everyone assuming your relying on medieval levels of technology. [Answer] # Yes You've solved the one problem that matters - you don't need to care about the resources, man-power, or time needed to build the wall. With that convenience, the only issue is encompassing enough area and resources to have the number of people you want and the ability to supply their needs. The question really is, how much of those needs must also be protected? As the old adage goes, a civilized society is but one meal away from anarchy. If you're looking to support a 10-million population city, you need to think about logistics. And logistics are the basic reason walls are no longer used by anyone. Walling a 10-million population city today would be expensive, but it could be done. But what's the point? Said city needs water, food, sewer control, and quite literally a *bazillion* tons of stuff *every day.* (Even your medieval city will have this problem... just less dependency on plastic, if you know what I mean!) Want to bring it to its knees? Roll up to the city's gates and stop all that stuff from entering the city. And a proverbial day later, the city would erupt into anarchy. But you've solved that problem Because you've made it economically practical to build as much wall as wanting. You can encompass the forests, mountains, grasslands, lakes, and rivers you need to supply your people with their needs while your enemies sit outside twiddling their thumbs. So, can it be viable? Yup. However... (And this is really important) It's viable... unless you don't want to enclose that much space. Unless your wall is tremendously tall and frictionless, you'll need to dedicate a massive percentage of your population to manning the wall. My point is, walls also don't exist because they don't really solve the problem. For a city the size you're talking about, you're really building a death trap for your people. As General George Patton once said, "fixed fortifications are monuments to man's stupidity." His point was that a mobile army can always outwit someone who's cowering behind a wall, and usually need only time to starve them out. So, in conclusion, take the time to think through your story. Does it matter if anyone thinks the wall is viable? There are reasons why most storytellers *don't* explain/rationalize/justify everything they do in their stories. If it's necessary to explain the wall (or feel comfortable that it's somehow "realistic") then you need to think through the consequences of having a fixed fortification of that size. Even in the medieval era, walls were beginning to become obsolete. Walls are great protection against raids. Not so much organized armies. [Answer] It's not going to be possible without hand-waving. The numbers you give puts each person having a plot of land 75' on a side. With that land, there must be shelter, livestock, a share of roads, markets, administrative buildings, etc. So on average, each person would have a tiny amount of arable land. The wall is possible, however - the Great Wall of China is far longer than what is needed to ring your city. [Answer] If this is a phantasy world, you have options, besides saying "Its just magic look no further!". OP doesn't specify. but in D&D there are methods, resources and opportunities to expand living conditions for city dwellers. The natural world offers many resources to combat some of the obstacles that get in the way of city growth. Sewer and garbage. Many organisms in nature are dangerous but have benefits to their eco system, these can be adapted to the city health. Green slime and Gelatinous Cubes cultivated to exist within the sewers and kept contained and at bay with magically heated sewer grates break down refuse that normally chokes even the best planned sewers. Very wealthy residents can even have metallic or glass enchanted canisters that contain the green slimes to devour waist within the home easily and efficiently. IE\* Garbage Disposal Food Preservation is a major issue with transporting large quantities of perishable commodities. Salting and drying can only do so much. Refrigeration is accomplished by farming Brown Mold. and endothermic mold that absorbs heat within the general area. Metallic cubes of differing shapes and uses with the mold sealed inside is sold by specialized and experienced brown mold farmers. cold boxes are this way "powered" and perishable food is preserved. Many flora and fauna of the phantasy world possess effects that can mimic what today we lean on for tech. Cooling, heating, lighting, even transportation options would not be ignored by those that existed within such a society and have the means to benefit from their use. [Answer] As has been pointed out, food is the main problem with such a large population concentration. Here is my suggestion for getting around it: use magic rituals to increase the crop yield of the fields. If this is at all possible, it's going to be something that a lot of people will attempt because the benefits will be huge. You said that constructing the walls took a long time and magic. If you need less magic power to maintain them, you now have an excess of trained magicians to help out in the fields. They could go about it in multiple ways too: you could make plants hardier and more more fruitful, kill or drive off weeds and pests, or maybe something time-related to accelerate growth and allow more harvests per year. Mix and match and you get a lot more food out of the land, especially near the city where it is most needed. [Answer] According to this [site](https://en.wikipedia.org/wiki/List_of_largest_cities_throughout_history) Ancient Rome did pass 1 000 000 inhabitants, just as Baghdad or Beijing (or other Chinese cities) had reached 1 000 000 inhabitants and beyond during Medieval era. Dutch mentioned that your city would have about 10 000 000 inhabitants. It may be doable if the focus of an entire empire is to provide for that city (and if we stretch imagination a bit). I would also take a look at historical methods of implementing sewage systems (both Roman and Medieval [sic!]) and ways of transporting water to the city. In regards to the food and waste: It may be doable, but it will not be pretty (and it will be smelly). If magic may be used as medicine then it would be of great help. But the communication would be chaotic. Traveling from one point in the city to another could take a whole day if not longer. [Answer] You might want to see answers to previous simlar quesitons. [How Many Soldiers are Needed to Patrol/Defend a Medieval Wall?](https://worldbuilding.stackexchange.com/questions/176034/how-many-soldiers-are-needed-to-patrol-defend-a-medieval-wall/176083#176083) [How much space would a city need within a ringwall to survive for an indefinite period of time?](https://worldbuilding.stackexchange.com/questions/173709/how-much-space-would-a-city-need-within-a-ringwall-to-survive-for-an-indefinite/173752#173752) [Build an impregnable fortress in the middle ages with modern technology](https://worldbuilding.stackexchange.com/questions/127177/build-an-impregnable-fortress-in-the-middle-ages-with-modern-technology) [How many people can you feed per square-kilometer of farmland?](https://worldbuilding.stackexchange.com/questions/9582/how-many-people-can-you-feed-per-square-kilometer-of-farmland) Those answers might indicate whether a city with an area of 2,000 square miles could feed a population of 10 million people. One way for a fictional city to feed more people with technology would be to build many 100 story buildings which were very wide, with artificial light for farming in imported soil, or with hydroponics, or aeroponics. And in a fantasy magic might provide the artificial light instead of technology. And in a high tech society food might be artificially synthisized with chemicals. And in a fantasy story food for a city might be synthisized by magical spells instead of by technology. ]
[Question] [ introduction My world is made of a super-continent with very little isles, it has 100 countries, 97 of which are on land. 3 of those are underwater for folk who are able to live confortably in the depths of the sea. Most of those countries are on the east side of the continent. The center of the continent is too dangerous and harsh to be populated, but still it's not an arid place and has some nomadic tribes that manage to survive far away from society. The entire world speaks similar languages, how similar? Like how all germanic languages are similar or all slavic languages sound the same and some are interchangeable. Question For a merchant living on a super continent would it still make sense to use ships as the primary way of transporting merch? [![enter image description here](https://i.stack.imgur.com/5JOo5.jpg)](https://i.stack.imgur.com/5JOo5.jpg) Also this is the actual size of the continent compared to the entire world map, this is a flat map, not a spherical one. [![enter image description here](https://i.stack.imgur.com/MtCWR.png)](https://i.stack.imgur.com/MtCWR.png) [Answer] I believe that you may be asking slightly the wrong question. You ask: "Will Ships still be useful on a super-continent" To which my answer is .... Yes! But a slightly better question is: "Where will trade occur, and through what means" Curiously, predicting trade is often a fairly good proxy for technical prowess and societal development (ie trade centers are often among the first places to adopt systems of currency, economics and written languages). So, the societal hotspots for your continent may be: [![enter image description here](https://i.stack.imgur.com/Ron6d.jpg)](https://i.stack.imgur.com/Ron6d.jpg) The area around Solnia is crammed with countries and easy land routes, quickly supplemented by sea trade. The sea is sheltered by the spit of Uruslania, and so sea travel is practical and easy in this region. As soon as rudimentary boats have been created, Velsia will be able to trade "across the sea" with dozens of countries. (I can imagine Velsa and Riveso as the capital of the world in the early days of sea travel - similar to what Rome was. Heck, put a shoe-shape on the end of the Riveso Peninsula and it Velsa and Riveso are practically Italy and Greece) Similar stories play out in the other circled regions, though probably to a lesser extend. Crinteto region I imagine as a bit of a late-comer to the party, as it is more exposed. Ship designs from that region have smaller cargo payloads, but their shipbuilding is highly advanced. Their captains known for sea-faring skill. But they don't have a great economy. These hotspots will generate internal trade via short sea routes, but until shipping advances allow longer distance travel, they won't really interact other than via long-distance-road transport - [silk road style](https://en.wikipedia.org/wiki/Silk_Road). I don't know exactly what tech level required is. 17th century ships totally could, but even in the 2nd century, [India was trading with China via the sea](https://en.wikipedia.org/wiki/Maritime_Silk_Road). Anyway, after ships reach some level of seaworthyness able to cross long distances (perhaps the designs are originally Crinteto?), sea trade really takes off, and the land routes change. In particular, notice how narrow it is between Torsand and Freinsia? That's a prime land transport route. Goods may be transported in from the south, hit a port at Freinsia, be transported by land to Torsand, and from their access dozens of other countries. Iragoa or Numidia may frequently fight for trade deals, or may become neutral (like Switzerland, which historically had a lot of trade passing through). Mariteto and Cirta are also a candidate for a great overland route, but there aren't many socieities over on the west. But imagine if Verisianio wanted to trade with Parasinia. Either they have to go anticlockwise and possibly use the overland route at Freinsia, or they go anticlockwise and they cut a long way off the journey by overlanding through Mariteto. However, Mariteto does have something else going for it: It'd be a great canal building project. I can imagine distant wealthy societies paying for the cutting of a canal through places like Mariteto and Cirintia. Virdria may be a bit remote to be economically feasible to drive a canal through. --- Here's a rough trade map showing some of the prime trade routes that I can forsee arising. Of course I don't know what the mountains are like, or if one country is mostly swamp, but it may give you some ideas where to look for interesting stories. [![enter image description here](https://i.stack.imgur.com/Bc1oI.jpg)](https://i.stack.imgur.com/Bc1oI.jpg) Some things to note: * Ships could stop off anywhere along the coast, not only at the points I've indicated. The points I've indicated them stopping off at are what I consider likely travel hubs. * The Dorn empire may make for easy land trading as fewer political boundaries occur. Similar reasons are for the routing of land routes through as few-er countries as possible. Oh, and vikings are totally found in Iberia and raid across to Parasina. --- A couple interesting things from comments: * @FuzzyChef points out the interior of supercontinents are often deserts - which are inhospitable and hard to travel across. This will help drive trade via sea, and may also explain why the west doesn't have many empires. * @clockw0rk mentions that the underwater cities will also drive more sea trade - both because they provide trade destinations and because they may be able to with assist technology and personal. I do however think that most transport would be open sea rather than through underwater caves - though underwater caves would definitely be the cool solution. [Answer] There is preindustrial transport rule of thumb: * cart transport is ~5 times less expensive (per ton\km) than pack animals river transport is ~5 times less expensive than cart transport * ocean transport is ~5 times less expensive than river transport So it was more expensive to move goods on pack animals ~100 km from port to farm than to move them from England to North American colonies. It is very approximate rule - sailing 100 km in Ionic sea and in Roaring 40s is not the same, you may have a nest of pirates in the way, land transport may be safer even if more expensive, etc. So if there is no river then ocean then ship is ~25 times more efficient than cart, and if there is no good road (you have to go over mountains, for example) - then its ~125. Even neighboring countries may prefer to trade most of their goods via ocean rather than land, even if you have to go 10x bigger distance on ship. [Answer] There cannot be a single answer, it depends on the location of the departure and arrival places. It's all a trade off between the cost of the two alternatives: 1. going from A to B directly on land 2. going from A to the closest port, then travel by sea to the closest port to B, then go to B. Within the cost you should include: * how long does it take to go from A to B * how likely is the trip to succeed (an option that costs 1 but has a 0.01 success rate is less convenient than an option that costs 10 with a 0.5 success rate) For a reference, [this map](https://brilliantmaps.com/travel-time-rome/?fbclid=IwAR2RUskAoeN_jYc0ih7BS4k2Ma7s3GGqYnW4HEZDngu7yyUpo2WHYIWr-gc) shows how long did it take to go from Rome to other places in the Empire [![enter image description here](https://i.stack.imgur.com/RB8A0.png)](https://i.stack.imgur.com/RB8A0.png) Notice what a big difference does it make the presence of the sea [Answer] It depends on where the rivers and mountain ranges are, and on whether there are any rival states that make trade difficult in certain regions. [Answer] Consider this completely fictional planet with a super-continent: [![enter image description here](https://i.stack.imgur.com/f1k2f.jpg)](https://i.stack.imgur.com/f1k2f.jpg) Remember that Europe+Asia+Africa is the equivalent of a super-continent, and for a long time, nearly all trade was within that super-continent (and to a large extent, within small parts of that super-continent). Even nowadays, a vast majority of long-distance trade is still sent by ship around/through that super-continent. The disruption following the blockage of the Suez Canal last year made that abundantly clear. Even internally, a lot of trade was done using ships (over rivers and canals) in large parts of Europe and elsewhere for a long time. The move to trains and then lorries is quite recent. The consequence is that many of the largest cities in the world are either sea ports or on large rivers (or both, on estuaries of large rivers): * Tokyo: sea port * Shanghai: on a river / sea port * New York: sea port * Istanbul: sea port * Los Angeles: sea port * Paris: on a river * London: on a river / sea port * Hong Kong: sea port * Amsterdam: sea port etc. Though of course they current size is recent, they gained prominent status because of their situation quite a long time ago. [Answer] Yes, definitely, just like it happened in real life. Traveling between the opposite sides of your supercontinent would be much easier by sailing around, than going over land. My proof is that in real life, much bigger detours were made to avoid land journeys. In the USA, the biggest cities were on the two coasts, and people traveled between them mostly by ship. Before the Panama Canal was completed in 1914, the journey was very long, but still preferable to the land route. Even in the late 19th century, when there was a rail connection between the two coasts, travel (and especially bulk cargo transport) by ship was still used. If this real world detour was historically preferable to the land route, then surely on your continent the (significantly less than real Earth) detour will be preferred over land routes. [![image from Wikipedia](https://i.stack.imgur.com/SeB8H.png)](https://i.stack.imgur.com/SeB8H.png) (I know that they often used the Magellan straits, this drawing is only an illustration for the distances involved. And yes, passengers often debarked in Panama, crossed over land, and boarded another ship, but even that is a big detour, and not really practical for cargo, making the long detour common until the completion of the canal) [Answer] From what you've described about the world, it seems like the large Western/central region is difficult to pass through on land. Those in the Southern countries would want to sail to the Northwestern countries instead, for example. Another thing to consider is with so many countries on the East coast, passing through each civilization might be a logistical hassle (border patrols, tolls, political conflict). It might be easier to simply sail around them than travel through so many. [Answer] If they wanted to get from one coast to another, then sure. Especially if there were barriers like mountains on the land routes. Then again, such a large ocean might be an extremely windy and stormy ocean, which could make sailing tough. Although maybe the windiness could help too.. [Answer] ## Canals... depending on geography Consider the Guineas in South America (French Guinea, Guyana, Suriname). Almost all the development is coastal. The countries lay claim to vast inland areas, but it is deep jungle with precious little development or human settlement: mostly it belongs to the animal kingdom. Your eastern peninsula has many countries, but almost all are coastal. So they might work like the Guineas, with all the development coastal and the inland borders being mostly notional, as the territories are difficult to inhabit or control. However, that doesn't work for the main continent. There are many countries entirely landlocked. So either a) they don't trade much and are largely self-contained (like the Plains Indians)... or b) they rely on navigable rivers or man-made canals, like most of Europe. Canals were being built 2500 years ago by the Chinese. It can be done by any nation with water and sufficient organization; it's certainly easier than building the Pyramids, and with much better economic payoff. You said "pre-mechanical-engine" -- that is important. If you can build and engine, you can build rails and locomotives, and that's the end of canals for any but the lowest value bulk commodities. So depending on your geography, era and national determination, you may be talking about the "age of the canals". You would have to figure out whether the "lock" gets invented (1000 years ago on Earth), as that will greatly increase the reach of canals, making it unnecessary for all canals to be dug to the depth of nearby rivers. (The only way a waterway can be navigable and at a slope is for the slope to be very slight and for the flow to be enormous - pretty much diverting a large river. Water supply is a frequent problem for canals; some even had elaborate pumping stations.) [Answer] Note that there is something called a tow barge. This is basically a ship being pulled by a horse who's walking next to it on land. These were the superhighways of the past and are most effective inland, not across seas, so these are perfect for a supercontinent. [Answer] If your supercontinent have large and very long rivers like those The Mississipi river and those rivers on the Amazonia then it makes sense to use ships for transportations of goods and people but they would needed to be found throughout the entire supercontinent. In this way most cities in your supercontinent would have a port for goods and people to arrive and leave. ]
[Question] [ I am working on a Hard Sci-Fi novel. In this novel Humanity has set up a drilling operation on the fictional exoplanet Hela. They are drilling for Trivesene, which is an Oil like viscus organic substance found in reservoirs underneath the oceans. Trivesene can be turned into the solid Petramene though carbonization. Petramene displays superconductivity at room temperature, a wide pressure range and a critical current of 980 Amp/mm². In the spirit of Hard Sci-Fi, I want to give Petramene a functional chemical formula. Please note, I know this formula will always be bs. The chances of a random compound being superconducting in the way described are 0. But this is not the point. I want to have a formula which passes the "vibe" check. I.e something a Chemist could look at and not see any immediate problems. Such as impossible / unstable bonds. This is my personal goal, a Formula which works on a technical bases and seems reasonable. Why is this needed for the Story ? A valid question I am sure some have. This problem could be avoid if the formula never came up. My research into the impact of a Room Temperature Superconductor has however lead me onto a problem of plausibility. The TLDR is that a RTS like Petramene would have such a fundamental and wide spreading effect on Humanity, it can only be compared to the invention of Electricity. We are talking about such a drastic shift in how things are done, history would be divided into the Pre and Post Superconducting era. And personally I just don't buy such an important substance would not be drilled into Childrens heads in Chemistry 101. Like, we are talking about "Page one, what is a Compound ?", picture of Petramene to the left with the formula type deals of cultural significance. A gameshow question, that one fun fact everyone knows. Like how Mitochondria is the powerhouse of the Cell. Now I will come out and say that the story is about Environmental protection wrapped in a emotional exploitation metaphor, with the core character dynamic being metaphorical for how Humanity is threating the planet in their exploitation affords. So the story gives lip service to the Formula, just like it just acknowledges the existence of the Interstellar Ships that brought Ellie (MC) to the planet. It all exists in the background and has limited importance to the plot. But, I am personally not satisfied with leaving it at that. I went into a lot of afford for instance in making the Interstellar logistics work, and this lead to a couple of cool scenes as well as a central part of the ending. And while I doubt a chemical formula will have a same effect, I still want one just to maintain the standard I set for other aspects. Be it logistics or the Alien lifeforms. What I have so far Since the goal is to make a fake compound which passes as a Superconductor I went to this [list](https://en.wikipedia.org/wiki/List_of_superconductors) and some other sites to create a collection of elements found in real ones. [![enter image description here](https://i.stack.imgur.com/HslXf.png)](https://i.stack.imgur.com/HslXf.png) These are all the elements which could reasonable be a part of Petramene. Furthermore I was advised by a friend to look into [Covalent superconductors](https://en.wikipedia.org/wiki/Covalent_superconductor#Intercalated_graphite) as they contain a lot of Carbon. Why Carbon ? As I mentioned before, Petramene is made out of Trivesene. Which is at the end of the day just a very complex organic compound. So it has to be made out of dead stuff. Similar to Oil. To illustrate my motivation behind how Trivesene is made on Hela, but not Earth. Because if I am going to claim this stuff is worth going Interstellar for, then there better be a good reason for why it is not abundant on Earth. Two factors are responsible for the relative abundance of Trivesene on Hela, but lack on Earth. First, Hela has deeper oceans (up to 30 kilometers). Second, Hela is a lot more geologically active. The depth of the oceans, in my mind, is important because it allows for dead stuff to sink to the bottom withouth being eaten. As life physically needs longer to adapt to the deep sea. So we have a layer of organic materials on the ocean floor which will remain untouched way longer than they were on Earth. The Volcanic / Geological activity comes into play as it deposits other elements, such as Iron or Bismuth, onto the organic layer. This mixture is then cooked for a few 100 million years and Tada you have Trivesene. This stuff does occur on Earth, there just isn't a lot of it. The conditions of Earth didn't allow for it to form, and even then Earth is older than Hela by about 1 Billion years. Trivesene is not stable and will eventually be destroyed by Natrual processes. Geology and life on Earth just had more time to get rid of the little bit of Trivesene there was. While on Hela, the stuff basically peaked right now. I think this justification (Wrong Conditions + more time to destroy it) are plausible enough for why there is basically non of this stuff left on Earth. But if not I am happy to change it with something more accurate. My original idea was to take real world superconductors, like $Li\_3Ca\_2C\_6$ and say $H\_2S$, and slap them together. For instance to form the total abomination that is $LiCa\_2C\_6Fe\_2MgSCu\_2O\_6$. But I was quickly told this was a bad plan. Which is true, it is lazy at best. Rules Looking at real Superconductors you can see certain trends. I want to use these trends, together with some personal requirements, to kind of limit where this formula goes. * Long Formula (high temperature superconductors tend to be very long compounds or Cuprates. Presumably a RTS wont be $Li\_2S$) * Carbon / Graphene structures (from a discussion I read on Organic Superconductivity, people seem to think if such a thing exists it would involve Graphene ($C\_6$ for example) bonds * Rare-earth element (in order for Petramene to be believable it would have to include some relatively uncommon stuff, Bismuth for instance, in the Trivesene form) * Organic (This is covered in the Carbon section but I just wanted to mention it. For the "backstory" to work it kind of needs to be organic) Le Problem And this is where I am stuck. I can make you a random Compound that does not break the bare minimum of rules, such as being neutral, but I just don't know nearly enough about Chemistry to really judge anything in particular. To add to the problem, I have a extremely hard time understanding what makes any specific compound easy to produce. The whole scenario kind of bets on there not being an easy way to make Trivesene. But if I slap out the Formular for Petramene I set myself up to the standard that there really shouldn't be an obvious way of making it. Making Petramene say $C\_2Bi\_2Sr\_2CuSO\_6$ wouldn't work for example. Hence the length requirement, as far as I can tell longer compounds tend to be harder to make on scale. I am for instance totally willing to say they can make Trivesene, but it would just take to much energy. To the point where going Interstellar is the better option. What I need Help first and foremost xD I don't really want to ask someone to sit down and make a 20 element long compound for some random stranger. So really, I would like some advice on how to achieve my goal. Are there any books I can read ? Any websites ? I am already through like half of [Professor Dave Explains](https://www.youtube.com/@ProfessorDaveExplains/videos) playlist of Chemistry. But lets just say I nearly failed to get into Uni duo to my chemistry grade. Of course, if there is some Samaritan out here who has a bit of time to spare I wont complain. But from all the reading I have done so far, this really isn't an easy task and requires some actual consideration. The moment a formula is dropped this way, the bar is sky high. I would basically say to the reader "And now prove me otherwise". Which is a really bad idea if I myself am not sure how bullet proved it is. I also want to end this by saying I know this is a really unimportant aspect in the grand scheme of things. If I didn't have the plot, character arcs etc. worked out I also wouldn't ask this. Because it is just not that important. But these things are worked out. If I cant find a solution, ill just drop the idea. But I had the same "Dive into a rabbit hole" with the interstellar logistics and making all of that Hard Sci-Fi and this resulted in some very cool visual / plot aspects. So I am willing to do this again. To an extend. Obviously we allow some significant handwaving by having Room Temperature Superconductivity in the first place. Closing Words Thanks for reading ! I hope this question matches the standards of this site and I explained my problem sufficiently. I did prove read this, but English is not my first language so please excuse any grammatical or spelling mistakes. If you need / want clarifications, I am happy to provide whatever is needed ! Thanks again and have a nice day ! [Answer] Frame challenge: what makes the material hard to produce isn't visible from the formula Chemical formulae are a simplification of what really goes on. There could be many materials with the exact same formula (and chemical structure) with wildly different properties. Let's take a simple example: ice. It's just crystalline H2O, right? No, there are actually [19 different known forms of ice](https://en.wikipedia.org/wiki/Ice#Phases). Why is this relevant? As far as we know, superconductivity is highly dependent on the structure of the crystal lattice, so your wonder material can easily be a highly unusual crystal form of an otherwise more common material (like SmFeAsO0.85F0.15). Which happens to be stable but to force it into the right structure you need to expose it to temperatures and pressures we can't produce on Earth, then cool it and relieve the pressure in a very precise way to avoid it reverting to its more common shape. And you're done. A plausible room-temperature superconductor. [Answer] ## Frame Challenge: The chemical formula is NOT common knowledge You have run afoul of [Average Familiarity Bias](https://xkcd.com/2501/). Because you have an in-depth knowledge of chemistry, you assume that "basic chemistry" is common knowledge, but it in-fact is not. Not only does the average person not know the chemical formula for olivine, feldspar, or quartz, but as hard as this may be to grasp, the average person does not even know the chemical formula for Methane or Table Salt. Most people know literally ONE chemical formula off the top of their head: $\ce{H2O}$. And they only know that one because it is the example every teacher at every level of school uses as an example for a chemical formula... and they only use water because it is so darn simple that it does not take a lot of explaining. Even if your substance were a relatively simple compound like $\ce{YBa2Cu3O7}$... very few people that don't actually work in the industry will EVER bother to memorize it. Instead of the the chemical formula, what will become common knowledge about it is the a description of what makes it a room temp super conductor. Imagine your substance as being comparable to Kevlar. Everyone knows what Kevlar is, it is some stuff that can stop bullets... but unless you are specifically a petrochemist who works in military R&D, you probably won't know off the top of your head that its chemical formula is $\ce{[-CO-C6H4-CO-NH-C6H4-NH-]n}$. Likewise, a lot of people will know what Petramene is, but they will know it in the context of what it does for them. They will know it is a room temperature super conductor. Even when you ask your smart fried, they will be able to describe how Petramene works by having a molecular structure that lines up such that electrons move along it in sync with the vibrating atomic nuclei... but even most of those guys won't know its chemical formula off the top of thier head. Since you said you just want this to be a piece of background information, there is actually a very slight change you can make that will solve all sorts of world building problems for you... have people NOT be able to answer the question when it comes up. It means that no chemist can ever call you out for your BS formula, it means no future discoveries will make your world look silly and dated, and most importantly, it shows off the actual ignorance of the people in your setting which is important when telling a story about "Environmental protection wrapped in a emotional exploitation metaphor, with the core character dynamic being metaphorical for how Humanity is threatening the planet in their exploitation affords." By using your background banter to highlight how little the average person actually knows, you will better server the main goal of your story. [Answer] If you want to go tongue in cheek, you might go with something like $FRh\_3HeCuReN\_2Th$ or $NO\_xReSi\_2STaNCe$. At the end it works perfectly fine with Unobtanium and Handwavium, not counting all the space missions and probes... [Answer] The problem here is that Interstellar travel is going to be extraordinarily energy intensive (vast nuclear fusion powered engines don’t really provide enough oomph for the required Interstellar travel by a wide margin), whereas Trivesene is just chemical synthesis even if it involves high temperatures / pressures and reactive chemicals it’s unlikely to be anywhere near as energy intensive as interstellar travel. You might be better off saying something like this: The structure of Trivesene is not well understood and is currently the subject of a great deal of research and debate. Although the empirical structure has been established as Sb2N7B6C15EuGdY2U3 it has not been possible to establish its structural formula. Trivesene is readily and very rapidly degraded by high temperatures, ionization, x-rays and even UV. Crystallography, mass spectroscopy, scanning electron microscopy (and many other instrumental techniques) have failed to provided any useful information. The infrared spectra has been measured but the spectra is difficult to interpret as the few peaks seen do not correspond to known bonds or functional groups. Experts are still trying to interpret results of analysis using magnetic resonance spectroscopy. The spectra has simply been described as bizarre by one team at Oxford. Despite the fact that Trivesene and its decomposition products are non radioactive, the latest theories suggest that some exotic form of nuclear matter may be involved. How this could possibly be achieved is still a mystery. [Answer] A problem I see is that as you describe it, Trivesen must be some very complex biomaterial. It has to be, artificallly reproduing it is so challenging it was easier to just go interstellar instead! Postulate: The complexity must be on the molecular level. Exotic crystal structures won't do, as you postulate Trivesten to be a liquid, and also because you carbonize it later which would alter the lattice. At this point, the material must have the complexity of some proteins - othervise it's implausible that a civilization capable of interstellar travel can't recreate it. Problem: Proteins have very poor outlook for forming a superconductor, exactly because of their complexity. I don't think it's plausible at all. The main point of superconducting is to form Cooper pairs of electrons that together behave as a singular bozonic particle - and this is disturbed by the slightest crystal imperfection. But a protein is so much larger than the electron that it wouldn't even "realize" it's in a lattice! No wonder most superconducting materials are alloys and have a mostly ionic lattice. (Pherhaps a superconduction expert chimes in with a counterexample though.) Solution: Make (most of) the protein the backbone of the superconducting lattice, not the part of it! Suppose the protein has, for example, a helical shape, forming a tube, or pherhaps a branching, net-like structure of tubes. During the carbonization process, the part of the Trivesen molecule inside this tube undergoes a certain dissociation, and metallic atoms previously part of the structure break from it These then form nanofilaments of some superconducting alloy within the tubes. The remnant of the Triversen provides an isolating wall to these tubes, leading to an unique one-dimensional quantum confinement of the electrons, which in this exact arrangement enables the Cooper pairs to stay stable up to temperatures beyond room temperature; hence room-temperature superconduction. You can also swap the nanotubes to a layered structure (think of cell walls), and have nanolayers instead. ### What does this mean to your question? *The total chemical formula is absolutely irrelevant**. Not only for the superconduction, but in general too. Proteins are huge: a random example, the protein [8DEQ](https://www.rcsb.org/structure/8DEQ) has 19.400* atoms (and it can get much worse, [well beyond 100.000](https://www.rcsb.org/structure/7nhn)). You never refer to proteins by their stochiometry - it would be like describing the ISS by the total number of screws and wires in it! The only important thing for your story is that at the right location, it contains the elements that you need for the superconducting filament. The rest? Nobody cares. The structure matters, the stochiometry not at all. --- For demonstration, here is the shape of the mentioned protein (image from RSCB, also [check out in 3D](https://www.rcsb.org/3d-view/8DEQ)): [![enter image description here](https://i.stack.imgur.com/7HCGE.png)](https://i.stack.imgur.com/7HCGE.png) [Answer] You are probably right. Carbon is a super-resistor, a resistor, a semiconductor, a conductor, and possibly a superconductor. If it superconducts, you want to inject a few more electrons into the delocalised pi conduction band. You may have superconductivity in the inside of buckytubes, though I don't know anyone who has proved it exists. But carbon is a very good starting point. What is the scale of your superconductivity? If you are using it to transmit power then there are all sorts of problems, particularly at either end where the power goes in and out, and you have to couple your super electron wave state to the external world. If you are trying to make powerful magnets then you can make a molecular-scale magnet with a small current endlessly circulating in the pi-bands as a magnetic isomer, and then crystallize that. No in or out, just a closed loop. You could also build molecular-scale magnetic logic circuits. I used to work with superconductors. I would have loved to build the magnetic isomer magnet. [Answer] When I was 12 I read James Blish's Earthman, Come Home, 1953. There was mention in one scene of a poisonous gas named Hawkesite, and the protagonist Amalfi thought that it was also called, "for no discoverable reason", by a very long chemical name. I looked at the very long chemical name and didn't try to read it, because it was too long and complicated looking. Later there was a scene in a bathroom and Amalfi noticed that the floor tiles were arranged in a complicated pattern of rings which reminded him of the chemical structure of Hawkesite. And years later I was reading the section where Hawkesite was mentioned again, and I saw the long chemical name polybathroomflourine and realized that it could be pronounced as "Poly-bath-room-floor-ing". So maybe you should get chemists to make up long and complicated chemical names, some components of which sound like normal worlds, and which more or less add up to phrases that people might possibly say. And maybe the chemists can also make up the formulas which would go with the name. You might hold a contest for the most real looking chemical name which sounds the funniest when spoken. And maybe you can say that the name use by the characters is a pun that someone made up because the real formula reminded them of a phrase which is common in their society. If so you don't have to give the real chemical name. [Answer] Earth-rare Isotopes Most introductory Chem-101 courses explain the basics of how Protons, Neutrons, and Electrons come together to form the different elements; along the way Isotopes are often defined and then quickly glossed over as "behaving chemically the same as all other isotopes of that same chemical element". Although that statement is mostly true, it isn't precisely true. While chemical bonding is driven by the electromagnetic forces between the Electrons and Protons, it is incorrect to say that gravitational forces due to the Neutrons have absolutely-zero effects. A heavier nucleus will more strongly pull electrons inward: slightly shrinking the atom's ionic radii compared to normal. Generally, these sorts of tweaks only slightly affect the properties of an isotope-specific element or an isotope-specific molecule; for example "heavy water" D2O boils at 101.4°C instead of 100°C for normal, everyday, "light water" H2O - which is why it gets glossed over as "basically the same". In the case of high-tech materials, though, various parameters are tuned by changing the composition and processing such that just the right crystal structures are formed. These tiny isotopic tweaks, therefore, might be just enough to make some 'boring' material 'extraordinary'. Perhaps the planet's lifeforms have bioaccumulated extraordinarily-pure Carbon-13 compounds which eventually became the Trivesene, or maybe it's an extraordinary abundance of of Hydrogen-2 on your hydrocarbons, or Nickel-64 (or any combination of multiple such processes). --- All this should let you basically just pick a realworld compound that mostly fits the bill (other than being "RT" superconducting) and then allows a handwavium explanation for why it goes RT-superconducting when sourced from this particular location. (Assuming nuclear-enrichment technology isn't massively-cheaper in your fictional universe). ]
[Question] [ Closed. This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 2 years ago. [Improve this question](/posts/209657/edit) What steps could people take to avoid children who are attracted to them magically? The nature of the attraction is that it induces in the nearby (around a km^2) children an ability to sense the attractor's location, and a desire to seek the attractor out. This is the only effect, and it cannot be blocked or contained. The steps to avoid the children should be relatively cheap and not overly burdensome, while still being effective. The method should also avoid using magic. The technology is at a modern level. The population with this attractive power is small, but still great enough in humber that useful services or products would be created [Answer] Their parents will prevent them from coming. Take up residence in a neighborhood with children. You will attract them. Your house is locked. They will accumulate in your yard. It is a safe yard for children and it has some nice things and some chickens. Parents will notice the children are gone and go looking. Other parents will discover a lot of kids in your yard. They will be sent back to their respective homes. You will apologize. Children will come back. Parents will now correctly guess where they have gone and come to collect them. You will apologize. Parents will note the children making further efforts to go to your yard. They will prevent them from coming. Parents will take shifts collecting the ones who evade their own parents and bring them back to their own parents. Some parents will punish their children such that they no longer try to visit. Some parents will take the children on a daily visit to the yard and then home to get it out of their system. [Answer] Don't try to suppress the power - make use of it. Or find somebody who does. * Teachers / on-site janitors at schools * dentists / pediatricians / the former's nurses * traveling ice cream salesperson / their spouse * tour guides for child-friendly tours * if it's short-range enough, a really good babysitter ... Or, if the power is strong enough, and your dislike of children likewise, you could strike a deal with a child detention center. You would have to live on-site 24/7, but you could barter for a king's life in there. And even if some deliquent does find their way out of their designated housing, they will be much more easier to collect, since they'll be orbiting your house instead of roaming the world. [Answer] Besides @John Dvorak's excellent answer, there is an alternative solution if the character REALLY wants to avoid children as most as possible. ## Work in a place that actively bars children For example, in a nightclub. A few miscreants might try to sneak in to seek you, but they'll be deterred by security and / or other staff as they absolutely cannot be in the venue. You sleep during the times when they are expected to be out and about but they should be under someone else's supervision (e.g. at school or with parents / guardians) If you also live in the place (e.g. in a loft upstairs), little chance to be ambushed during commuting and you can also have supplies delivered easily, and it gives you good cause to call the police / CPS on someone who is trying to reach you during the day [Answer] Doesn't something similar happens already in every house where there is a child? As soon as an adult has to use the restroom or take a shower, the child will want to follow him/her. If the doors have a childproof lock, the adult will be able to enjoy the privacy alone, if not... [Answer] This is a common situation for certain people today. They have to avoid children. So, they map out where children are and don't go near those locations. Most parents keep their children fairly close to themselves or certain trusted locations. These people can't work in any of the occupations listed in @John Dvorak's answer. On Halloween, they keep the doors locked and lights out. When children are out playing in the street near them, they have to stay inside. They go shopping when most children are in school. (No, I don't have personal experience of these restrictions; I know some people who have them.) [Answer] ## Gated Communities: An old solution, and justified for a magical minority that attracts children. Locate walled compounds in the country or industrial parks away from "normies." Jobs are close by in industrial parks and far from kids. Telecommuting would also work. Kids are either out of range or kept out by the walls and security. Most kids aren't going to be able to get through a wall or past a guard. Besides, where are the parents? I would lobby congress for this, and screw civil rights. The harassment level would be such that these folks would flock to such communities, and it would likely also become mandatory living places for pedophiles. Yes, it's creepy and unfair. Ask minorities how they feel about being redlined, and ask whites if they want to leave their gated communities. [Answer] # The Mosquito A device to accomplish this already exists: <https://en.m.wikipedia.org/wiki/The_Mosquito> Youths are able to hear higher frequencies, and if they are emitted with enough power it might deter them while not affecting older adults much. [Answer] You induce in children the urge to locate you and seek for you. You can consider using a diversion. If you know the nature of the attraction be it magical or be it physical, you can use this knowledge in your advantage. Try constructing a device that mimics your ability to induce. You can place these on flying mechanoids. Program them to make them fly to children. The children will be looking for hot mechanoid instead of you. [Answer] ### Smell Really Bad Or maybe look very scary, although that isn’t as reliable. Everybody will avoid you, but especially children. [Answer] Build walls around you at km^2+200ft distance. Buy an abandon ghost town, and wall it off. As long as you live in the center. Should probably go at least 200ft extra to give yourself wiggle room. ]
[Question] [ TLDR: how long would it take modern day humans to adapt to an incident where dungeons appear on earth and spits out monsters? I am writing a fantasy/apocalypse novel set on modern day earth. One day, 60 dungeons appear on earth and monsters invade from it. These dungeons are different in the sense that there are seemingly infinite amount of floors and monsters in the dungeon. In the initial invasion, around 500,000 monsters come out from each dungeon. The humans must kill all these monsters and start proactively hunting them inside the dungeon in order to avoid another invasion. Humans can also level up and get classes that make them stronger. I want the society to adapt to dungeons by establishing guilds and a system for hunters (humans with classes) to kill monsters in dungeons. Couple of details that might matter: • Firearms and other modern weapons only work on monsters when they are outside the dungeon. This is because monsters are creatures with mana and mana is originated in dungeons. So, they are “buffed” inside dungeons (Mana does slowly leak into earth from dungeons). • If the monster populations in the dungeons are not curbed frequently, then an invasion can occur where they come out of the dungeon. This also happened when dungeons first appeared. • There is a game type system; where all humans can view their status and level up by hunting monsters. You can get a class at level 10. Most civilians never achieve this and stay in single digits. • Since there are only 60 dungeons and there are 195 countries. I have it to where the dungeons appear in the top 60 populated countries. The smaller countries are safe; for now… • Monsters killed inside the dungeon can drop loot: magic reinforced weapons, potions, skill books, armor. Once a monster is killed its corpse will immediately dissolve into the dungeon and loot will appear randomly (Therefore no corpses can be harvested). On the lower levels, there are herbs and ore veins that can be harvested and retrieved. So how long would it take for humans to adapt to the point where they can regularly hunt monsters and keep the monster populations down. Edit: The dungeon cannot be destroyed. It is a portal to another space/dimension. Also there is no benefit if a monster is killed outside the dungeon. The corpse will still dissolve and there will be no loot. So invasions only cause harm. [Answer] Assuming these dungeons have appeared in countries with modern military industrial complexes 48 hours to fully contain 72 hours for the first submission for planning to automatically turn anything coming out of the dungeon into food/fuel/other usable resource. See our previous questions on [dealing with zombies](https://worldbuilding.stackexchange.com/questions/71877/how-can-i-build-a-door-to-repel-a-horde-of-zombies) where half the answers either put them through a wood chipper or a rock crusher. You see, in the real world we're far more efficient about dealing with such problems than fantasy games would have you believe. --- But you want people to have access to these dungeons, not have them controlled by major industrial influences. What you need is chaos and corruption. Syria or Libya for example. Places where the outback is controlled not by governments and corporations but by militias and corruption. You'll have to pay a fee to go in, but you'll get in. Whether and how you make it out again, well that's another story. [Answer] *Oh, we are going to science the heck* out of those things!** As others have stated, monsters outside are not a problem, just point an [A10 Warthog](https://en.wikipedia.org/wiki/Fairchild_Republic_A-10_Thunderbolt_II) at them. Modern warfare is lethal on a level that no dungeon monster can possibly compete with. In most countries this will happen in a matter of days. Then we will send in some brave men to establish a beach head. This will just be a matter of putting in a really sturdy and lockable door some way down the corridor. The area on the outside of that door is now safe. Well, for a while. When the inevitable Really Big Monster shows up, the door should at least slow them down to the point where people can be evacuated. Make that multiple doors. So, we now have a portal to another universe with different laws of physics, with a safe area where experiments can be run. The world's scientists are going to be fall over each other trying to get there to test their pet theories. Some will be studying the portal, trying to duplicate it and also how to close it in an emergency. Others will go deeper and find out just why firearms doesn't work inside. When the best minds of the planet are all working on this, they will get answers. Maybe we will learn how to open portals of own to other realities. That would be immensely useful. People will be asking for permission to explore beyond the door, but I really don't think most governments will allow that. Of course, with many portals to choose from, there will probably be exceptions. Once we have figured out how to shoot things inside, and we will, the fun begins. But it will not be individuals wandering in without a clue, it will be a fully military operation where a large number of people go in, conquer areas and keep them conquered. Supply lines back to the portal will be maintained at all times. Any loot will be taken back to the scientists for study. With a large number of soldiers per enemy there will few level-ups. The few people who do will also be taken to the scientists for study. Eventually we will learn how to use magic back on Earth and life will never be the same. [Answer] Most of what these people have said is correct, although they assume a lot. Depending on where you put the dungeons and the first invasion, it can go a lot of ways. For example, if that first invasion is enough to cripple the society where it started and it killed a sufficient amount of people, there could be chaos and the time to set up a basic defense for the monsters could be a while. Also, since loot doesn't fall outside of said dungeons, it might take a while before anybody figures out that going inside the dungeon might be lucrative. Also, who cares about the dungeons anymore if we can just kill them every time they show up with our guns and stuff. I say you make the guns ineffective, and the monsters drop loot wherever, this way people will understand what it takes to defeat these things and where to go to do it. I say if you leave a objective of removing these monsters forever by getting to the end of the dungeon or whatever, people will be much more cooperative, but otherwise people will make clans or something and will claim dungeons by killing anybody else who tries to go there. The only way that changes is if someone else moves them, or they find a way to make money on entrance, like Bald Bear said. P.S. the first invasion can drop some "warning" loot or something so everybody doesn't die. Also, if this is a "video game" kinda thing, maybe giving everybody a certain thing at the beginning would be good, and based on their personality and fighting style and stuff could lead them to adapting into a class, instead of all of a sudden being in one. [Answer] While the accepted answer is likely the closest to the truth and the most likely initial scenario as written, it's not going to make for a very exciting story. Or rather, it will make for a different kind of story. Note My initial reference for the countries that will spawn a dungeon will be the [List of countries by population](https://en.wikipedia.org/wiki/List_of_countries_and_dependencies_by_population) from Wikipedia and the OP's statement that the top 60 countries by population will get a dungeon. Numbers in brackets indicate their rank on the population list. Good news: Dungeons for everyone! TL;DR -- Best guess, maybe 6 to 24 months depending on damage done to the world in the First Wave. Expect all adventurers to be either licensed by a surviving state and/or owned by a mega-corp. ## Day 0: The Initial Invasion At this point, 60 dungeons emerge on 6 continents and a horde of entities 30 million strong spew from these portals. At this point, mana starts infusing Earth -- this point from the OP is important later. Some will no doubt be hostile and/or hungry and/or just evil by our standards. Some might be the equivalent of refugees hoping for a better life outside the dungeon. Others still might be denizens that leave to try to keep the invasion contained. The latter two points aren't really in the OP's question, but given that the dungeons are described as a portal to another place, I will assume it a fully fleshed out world down there and not just a Murderhobo Demesne. It is also likely that not every dungeon emerges in highly populated areas of their country unless Plot dictates otherwise. Canada's (#38) for one example is likely to emerge in a fairly uninhabited area of the country as most of their population is within about 200 kilometers of the US border. Not to say people will not be affected, just that it is less likely to effect a large population immediately unless it lands on one. Australia's (#53) will also not likely fall on a major population center as another example. Also, those invaders will have to deal with the possibly hostile and/or deadly wildlife -- Australia, I'm looking at you here for the memes. Humour point: The first class upgrade goes not to a human but a random Australian animal, probably a snake. As if they weren't deadly enough before … Some countries like America (#3), Bangladesh (#8), France (#20) and Italy (#23) will likely have their dungeons appear somewhere relevant and disruptive regardless of where they land in their country. Depending on each country's detection systems and how easy the dungeons are to detect, the governments of the world could be aware in minutes. Shortly after the invasion starts, The Twitterverse explodes with the news and first-hand accounts moments after emergence of the first portals that drop in a public area with a cellular network. Other social media platforms also explode in traffic due to this. This could bring the internet slowing to a crawl at least in the immediate term. It will have the side effect of definitely alerting the world that something is up. How bad the world suffers for it and the overall death count will depend entirely on where in the country each dungeon shows up. As one example, the UK's (#21) dungeon appearing in London, England will be a lot more devastating to the country than it appearing in the Scottish highlands. One opening near a nuclear power plant or other electrical generation plant could be devastating in a different way. Expect at least one international incident when a portal opens close to the border of another country that won't have one. They may or may not get along in time to gang up on the dungeon to contain it. This is where you shape your fantasy apocalypse and will set up the rest of the story. Three primary factors will determine the initial damage suffered by the world: * Where the portals emerge in each country * The amount of warning that the world will get before social media alerts the world * The immediate hostility/lethality of what escapes into the world. ## Step 1: Containment For the more militarily powerful countries and for the more readily accessible dungeons, forcible containment of their dungeon could takes days to a couple weeks as outlined in other answers that describe this process better than I could. This is of course, dependent on said countries not being crippled by the first wave of denizens either by dropping on their capital city and killing/eating/replacing leadership, devastating key infrastructure that prevents a swift mobilization, or triggering something really nasty in their rampage. Expect also at least one country to try something dangerously extreme and likely more than a little stupid to contain their dungeon. However, any containment most likely can't last forever by the OP's question. As mana leaks into Earth, it is well possible that the range that the dungeon monsters are enhanced by the dungeon's mana will extend outside of the dungeon proper which means that base guns could get less and less effective as time goes on. This may also mean that the border of the dungeon moves outside of its threshold as the dungeon's mana in our world increases. Countries fortunate enough to get a "friendlier" dungeon may be able to parley with a representative of a more peaceful faction of the dungeon dimensions for information and learn some of the rules that way and possible entreat for help against the more violent escapees. Should the Internet survive, expect YouTube to explode in monster invasion videos as the Twitterverse and other social media calm down slightly. Expect film of the Japanese (#11) dungeon to be thought of as a live action anime adaptation of something and everyone trying to figure out what based on what has emerged. Somebody will Instagram themselves holding a sword with a caption like "OMG! Where was that spider hiding THIS?" only with worse spelling. The big change will be the state's First Drop. It doesn't have to be epic loot, but the moment a giant spider dies and a sword appears, it's Science Time! For those countries forcibly containing their dungeons, this will either take the time needed to organize an initial extermination excursion or for the mana to become thick enough for the dungeon's edge to extend outside of its entrance. ## Stage 2: Stand Back! We're Going to Try SCIENCE! As stated in previous answers, this is where we as humans try to apply the scientific method to the Dungeons. Game designers might have a bit of a better time with some aspects of this given the video game feel of the Dungeon Dimensions. Expect questions like: Would bullets made from the metal of a magically reinforced metal weapon be possible? If yes, would they still work on the denizens in the mana-rich zones? Can these Skill Books be used by more than one person? What do those bodies decompose into and can we use it somehow? Expect a range of ethics and moralities to arise in dealing with the scientific research based on how people vie the Dungeon Dimension denizens. Excellent philosophical debates are also abound. Also this is the part where we begin to discover what the leaking mana is doing to the environment as it is effectively foreign radiation seeping into the world. Does this do anything to our indigenous flora and fauna? Can any wolves from the dungeon interbreed with the wolves of our world and create viable offspring? Can we survive this mana exposure long-term? Most importantly: Where did the straggling survivors of the First Wave go? Do governments have Shapeshifter Replacement Protocols? Just how many tentacles is too much for a single monster to have? It followed me home -- Can I keep it? I would expect multiple Internet forums dedicated to the theories and physics of the Dungeon Dimensions … or lack thereof. This is, of course, if the Internet is still present and mostly public. Any of the soldiers that might have gained a class at this point will likely be turned over to governmental scientists for study into that phenomenon, with results either publicly disseminated, kept carefully hidden, or leaked onto the Internet somewhere. Expect random stories on the internet to arise of civilians that have attained a class upgrade from the initial wave. They will be "recruited" for study -- method depends on country and its condition. Also, theories will be abound as to who gets what class as well as Facebook/Cosmo quizzes to figure this out. They may or may not be accurate. Initial small-scale expeditions begin with the goal to try and salvage the first minor items. Returning safely is more important at this point than loot. ## Step 3: ??? At this point, we have at least some of the rules of the Dungeon Dimensions, as well as the outside generally contained barring a fluctuation in the leaking mana causing an unpredicted increase in monster resilience. Eventually there will be a transition from a purely military operation into something else if it hasn't already due to crippling in earlier stages. It is quite possible that this will be spearheaded by some multinational megacorporation for the purposed of exploitative profit. Expeditions into the dungeons will be commissioned here and the first large-scale hauls brought up for examination and possible distribution. How and to whom they are distributed depends entirely on who owns the expeditions. # Step 4: Profit Regardless of how it happens, the end results will be the 60 countries will likely end up exploiting the dungeons for profit, like the gold rush or the push to the explore the new world. Each country will do it in their own ways. Dungeon towns will spring up where the containments were and soldiers will be supplemented by licensed adventurers. Those that cannot do the fighting will ply their talents elsewhere, supporting the dungeon towns, or continue on like nothing happened. I would expect a mix of surviving modern tech and fantasy trappings especially in the dungeon towns. Almost like a living renaissance faire at times for the dungeon towns. I would also not be surprised if at least one or two dungeons were in too inhospitable of an area to be completely maintained and thus unleash a smaller wave of monsters to mop up every so often by forces and locals nearby. It would be here that I would expect the truly adventurous to set up frontier villages in the Dungeons themselves should conditions be self-sufficient enough to permit it. In addition to the dungeon looting, expect additional geopolitical conflict as countries without a Dungeon to exploit try to get their hands on either the loot from one or launch a force to forcibly take a dungeon. That or corporations trying to get monopolies on the dungeons. ## The Rest of the World Almost forget about the rest of the world. If the initial invasion did not kill you, destroy your livelihood, or cause you to emigrate to a safer place, life will go on as per normal most likely unless you have chosen to involve yourself in the Dungeon Craze of '19. I would expect new niches in the workforce to open up as it would for any highly disruptive element introduced into the world. Farmers will still farm to provide food for the world and might have a surprising number of levels depending on their location. Mundane labour jobs will still be a thing, and office workers will still do paperwork. Topics might change, such as the guy whos child just hit Level 12 adventuring for Exploracorp or the executives discussing loot purchases over golf. There will be tales of common folk heroes that have managed to kill enough denizens to level up assuming that you can at least get partial experience for those killed outside the dungeons and just not get loot. The flora and fauna of our world will adapt and evolve to either use the released mana or to ensure they are immune to it. Neither will happen without losses first though. Nature will prove itself surprisingly resilient on this matter I would think. The Dungeon Denizens that escape into the world without being killed will provide new species for the world to adapt to as well as a new source for mythologies for our descendants. [Answer] Separatrix's answer above is correct, but here are more details to flesh out the story Military will surround each entrance within days, and it will take about a month to build a proper containment facility. Basically a straight concrete tunnel with dungeon exit on one end, and a large number of guns on the other. Tunnel wall can be made thicker from outside if stronger monsters start appearing, and interior walls have to be periodically resurfaced. Also, a Stargate-style steel curtain across the entrance (or movable concrete wall). To make things less easy, have monster teleport to random locations around the exit, rather than come out of the bottleneck exit. Then military has to build a wall around the area. The explorer teams are sent in between monster appearances. The goal is to explore and collect valuable minerals and herbs. Teams can be military, or corporation who pay military for access. If you want small-scale adventurer bands to go in, you will need large enough dungeons so corporations mine the large deposits, while small band explore the unexplored corners. Few reasons for firearms not to work inside. The entrance portal dissolves metal or gunpowder. Dungeon passages are narrow and curved, so you do not see the monster until it is a few meters away from you. Dungeon walls are super-hard (and irregularly curved), so bullets bounce all over the place, including back to the shooter. People will want to establish outposts inside the dungeons. So potential for turf wars between corporations. [Answer] I think an important clarification here is the size, class, and toughness of the monsters that can emerge from the dungeons. Separatrix is correct regarding initial containment if the monsters are things like Orcs, Elves, and Faeries, relatively humanoid creatures without much size difference or armor to withstand modern weaponry. If the second or even the first waves include Kaiju-class monsters at all even modern military complexes will be hard pressed to do anything but nuke it into oblivion, destroying any and all defenses previously set up. If that monster is the kind that thrives on radiation, anything like a Godzilla, or an exotic creature that feeds directly on energy input, even the nukes will fail or make the problem significantly worse. Modern military might is all well and good, but fiction and fantasy are full of creatures that have annihilated modern military forces, requiring specialized or downright strange solutions. Why not start out with massive armies of regular monsters, but intersperse a large amount of variety. Waves of Orcs followed by the full might of the Zerg, Mindflayers corrupting humans, night-stalkers assassinating key targets, and one or two Tarrasque or Kaiju. Once they've cleared out a large radius, or humans manage initial containment, they retreat back inside the dungeon to their respective floors. Have these waves get progressively worse until humanity's only recourse is to send troops in to try and find and stop the source, discovering both the mana management and the delay or reduction of the waves in the process. Maybe they have to kill a certain boss in order to stop the wave entirely, fighting to and killing a Tarrasque (that can only be killed by the magic spell 'Wish') which can only be killed inside the dungeon as there is no mana outside. This timeline starts off with 72 hours initial containment, 3 or 4 weeks for exploration or discovery before the second wave bursts out, then more waves every month until they discover that killing a certain enemy inside the dungeon stops the wave altogether. I'd say that would take about 6 months of dedicated research and experimentation, along with loss of life both inside and out of the dungeon to reach this conclusion. I'd add another 6 months of verifying this conclusion and the successful repetition across all the dungeons, strongly solidifying the culture of Hunters supplying the local economy with dungeon loot as a means of making a living. After this culture is established, the defensive perimeters will erode or be taken down while corporations vie for rights to broadcast raids or dedicate resources to research dungeon mechanics and physics. 1 year total adaptation timeline. [Answer] It would depend a lot on local policies, I think that the accepted answer works well for places where there is actually a military power that is organized and efficient, otherwise it would be chaos before there is actual containment. Take that one portal appears in 'El alto' for example (it is a city in Bolivia) which has a high density of population, the government would most likely fail to react and so would the military, and when they do it would depend a lot on the type of monsters that are on the dungeons for them do have any impact whatsoever. So a lot of deaths later, after the first world countries began to contain their own portals, they would start messing with other portals (or trying to help as they would put it), and of course most local governments would accept the their help without much options since they are in chaos. Now, if by this point the countries that managed to contain their portals started to investigate further, as Stig Hermer's answer suggest, and I completely agree, and they discovered that the portals are a source or materials, magic, etc the countries that where helped would absolutely be in a situation of debt so the resources would most likely be controlled by a few powerful governments, and that would bring a different world order. To answer OP's question of how long would it take for all of that, not thinking about the first worlds as most of the answers do that, but for the initial international interventions, I would say a couple of weeks after the first containment s were successful, and more if the country that has a portal that needs help is a dictatorship of some kind, or a political inclination that the helping country doesn't like... [Answer] It'd take two generations, possibly three. My reasoning is simple: 1. Every major event that impacted a generation has repercussions; with maximum impact in the generation it occurred. Take WW1; it took two generations, maybe three to come to terms with that. WW2 took longer because it included the Holocaust, which I don't think we'll ever truly recover from. Places that actually manage to contain or otherwise handle the invading monsters will start adapting in that generation. The next generation will likely think nothing of their new way of life, going to school alongside Orcs and Manticores. For them, it'll just be the way things are. Just like for WW1 or 2, there will be repercussions. Hybrids will be born, like Half-orcs, with unique abilities resulting from their monster and human sides (not to mention their Classes). Speaking of Classes, they may be revolutionary. If there's a Warrior or Soldier Class, then you'll have magically enhanced fighters. If there's an Engineer Class, engineering is going to improve drastically as members of that Class gain levels. ]
[Question] [ In a world where there is ever-declining population due to a phenomenon that has no satisfactory explanation, what could cause war or large-scale armed confrontations between countries or sections of the society? Assumptions: * No births have happened for a while. No new pregnancies are happening. * The cause for this population decline is unknown and there is no apparent cure/solution. * The decline is unstoppable; humanity will soon be extinct. Given that humans realize they will soon be gone for good, what could create a situation where human lives are intentionally harmed? EDIT: I noticed that I need to word my question better, so I'll add here what I posted in a comment. > > Most of the answers so far assume the worst of humanity; stuff like "Might as well do anything I want, since I'll die one day". The thing is, that is true for all humans even now. Why would the possibility of there being zero humans a few decades from now foment conflict today? > > > For additional clarity, consider the following: * The realization that there are more humans dying that those being born sinks in slowly. This isn't a T-virus/asteroid/alien invasion scenario, where humanity is given a few weeks till extinction. * For most people, news about economic indicators like labor costs or population decline isn't worth a lot of attention. So it's conceivable they carry on with their lives (for what I assume will be quite a while) until this starts affecting them personally. By then, governments & society are likely to grasp the fact that every human life is "precious", much like tigers or pandas today. So, I guess my question is, when governments are actively engaged in (however futile) efforts directed towards conservation of human life, what would cause war or any armed conflict between humans? EDIT 2: A lot of excellent answers. I'm going to have to pick out elements from each answer and cook up a cascading series of events that form the basis for some bitter resentment between the principal actors and a spark that starts the fire. If only I could accept more than one answer... [Answer] A rumour that that other country(or whatever else) has fertile women or men and some government decides that they have the military power to acquire them for their own country. If the rumour is not actually true, the war can last even longer because "they are hiding them from us". I believe there have been several films with similar plots where there was one pregnant woman who had to be transported from one place to the other and everyone was trying to capture her. [Answer] If you ask me the causes of war are ususally: Either: * Philosophical disagreements (By which I mean ideas about the nature of god, proper governance of the nation, the right to oppress other people and/or the distribution of wealth) or: * Scarcity of resources. (example: Oil, Precious metals and/or space) Philosophical differences is probably the easiest sell. A war could easily start over a sect of any major religion (or a new one) deciding that the human die off is God's will and either want to help out or hope to change the divine mind by appeasing it. ("We all must conform to these simple rules about food and clothes, then God will make us fertile again" ... basically the setting for Handmaids Tale thought... so I might end up feeling derivative.) As other users have already pointed out general hopelessness might very well cause an outbreak of violence. Look at, for example, Children of Men which has a rather similar scenario as the one described. However, while most fiction deals with the worst of humanity surfacing in a crisis most studies of real disasters do show that on at least a local level people tend to cooperate. So it might not be the best motivator, it's a powerful trope which we all know. But it is a trope. * [Henry W Fischer: Response to Disaster: Fact Versus Fiction & Its Perpetuation : the Sociology of Disaster](https://books.google.se/books?id=-H17D_PwL1IC&printsec=frontcover&hl=sv#v=onepage&q&f=false) * [Sarita J. Robinson: Human Behaviour When Disaster Strikes: Human behaviour in emergency situations](http://clok.uclan.ac.uk/9573/) As for scarcity I think as a motivator for war in your scenaroi it is trickier, with a decline in population most things naturally get less scarce as smaller amounts are needed to satisfy demand. And killing people who could be farming/mining/producing will essentially be highly counterproductive by make things more scarce, why send soldiers to the front when you could send them to the mines and factories? Perhaps a related or unrelated event to the die off also makes livable land more scarce? Global warming and sea levels raising, deforestation and growing deserts would might remove viable real estate quicker than natural human die-off. [Answer] A War of Retaliation or Revenge Say that one nation blamed it (I will just call it the decline) on another nation or a terrorist group took credit for it. Then it would boils down to, let’s make them pay for what they done to us. Even if it’s just a rumour or a religious hardliner saying this, conflict will arise. Much the same when London burned down the French were blamed and even killed for a crime they did not commit. It could even be used as a tool for control by governments, like this country/race/religion is holding the weapon that caused the decline if we take it we could find a cure...kill them all… we have nothing to lose. > > Lack of Hope leads to Despair, Despair leads to Distrust, Distrust leads to Conflict > > > [Answer] Decreasing population means less people available to produce resources and technologies. Scarcity implies higher value, higher values attract greed. If group A has two cows and group B not, group B will attack group A to take the cows. Better be killed trying to get food/water/shelter than reaching a slow death by simply waiting. [Answer] I don't think typically humans have an innate desire to protect other humans, other than their immediate family and friends. The impending extinction of the human race will not automatically make people place any greater value on human life in general. Conflicts will arise as they always do, due to competition for resources, or perceived moral superiority etc. I would expect that rather than large scale conflicts, there would be more "tribal" conflicts, and society in general begins to break down. If there is no clear scientific explanation for the calamity which has befallen the species, I would expect a lot of people will resort to religious and superstitious beliefs. This could easily lead to genocide against minority groups who are often blamed for the ills of any society. [Answer] Any war in human history has 3 motivations: 1. Money 2. Money 3. and Money There's a lot of excuses for it because as said by Goering why a farmer can go to a war if the best possible outcome for him is getting back from it in one piece. Excuses most used are: Religion, Ideology, Survival, Retallation, Freedom and any one you propaganda can get (those guys can be inventive). But the bottom line is some (usually old) guys want's to grab some resource (land, oil, people, trade routes, market, political power, hunt fields, potatoes, etc) from another (usually old) guys and they send (usually young) guys to solve the resources owmership question. They really don't care about unless they are good enough liars they can lie to themselves. That beging said you can set the war for whatever you want because in reallity those old guys really don't care about the long term future (they are old). [Answer] It's been mentioned in several answers and comments already, but if you haven't seen it already, go see [Children of Men](https://en.wikipedia.org/wiki/Children_of_Men). It deals with a very similar setting. [![enter image description here](https://i.stack.imgur.com/YXceK.jpg)](https://i.stack.imgur.com/YXceK.jpg) Inspired by (but not directly copying) that, one excellent way to introduce large scale conflict in a world such as this would be to have a cure pop up. What's important to keep in mind, because a cure like this would be a big deal for your setting and potentially quite disruptive to your plot, that there doesn't actually have to be one. People / countries just need to be convinced that there is a cure and that somebody is hoarding it. [Answer] Loss of hope and collapse of civilization. If the world is going to end, why not do what you want and damn the consequences? You'll see suicide, crime and increasing apathy increase over the years. Then as the last generation becomes teenagers and young adults, they'll ask themselves why they should do jobs that ultimately don't matter? Why they should obey rules from a dying government? Why they should care about anything at all? Revolutions will bring down governments. Hordes of like minded people will rove across the cities and land, taking what they want, destroying what they don't want, and fighting others for ever declining resources and to end their lives in a shower of blood and glory. When you have no future, why not make sure no one else has one either? [Answer] Moral superiority / Fear So if people are behaving like savages, and creating a civil war, still stable nations might fear that this behavior will lead to an earlier end of themselves and wage war against those nations in faster decline. (Religious) fanatism Think of the islamist idea of jihad or kamikaze attacks by the japanese. Humans will easily throw their life away if the apokalypse is coming and they do it for what they believe is a greater cause. [Answer] If all current forms of humanity are dying, then anyone with the technology to convert human consciousness into another form has the only hope. Such a technology is worth fighting for, as it is the only way to survive, even if in a different state. Post-humans will both be a goal worth gaining, or possibly in some circles worth destroying, or both (as many times what is forbidden for the populace is practiced by their masters). [Answer] Humans just went from being problematically numerous to being a scarce and rapidly diminishing resource, governments in countries with seriously aging populations, Japan comes to mind, could easily justify going to war in order to capture themselves an ongoing labour force. Once one country does it out of physical necessity others in less dire straits can start to justify similar course of action. [Answer] Consider that with a diminishing population, vital skillsets will be vanishing too. A nation that was previously nuclear powered might shortly realise that they don't have anyone who can keep their reactors from melting down. but their neighbours do... Extreme example, but I'd expect that head-hunting of this kind would quickly cross any borders, Upskilling would be a duty. If you can't do a dozen jobs then you become a burden fast on the people who can. Maintaining a modern standard of living takes a LOT of people with a spectacular range of knowledge and skills, to keep it going, some nations may press-gang or even enslave the citizens of a neighbouring nation into doing all the grunt-work while their own citizens fill the expanding gaps as people begin dying off. Of course, those other nations would take serious umbridge with this. They'd fight, and that would lead quickly to war, the losing side being taken into indentured servitude would give them serious motive not to surrender and thereby prolong the conflicts. Stockpiled resources too would be targets, nations cannot afford the time to dig up fuel or metals when they can simply take it by force or scavenge it. The more powerful nations would quickly resort to drone and remote warfare, their soldiers being far too valuable to risk in combat, but this would only last as long as the complex machines can be maintained and munitions and fuel provided. Ultimately, the most advanced nations would be head-hunting anyone with a background in longevity, fertility and indeed anything at all that can prolong the inevitable, they'd gladly take those people by force from their own countries. It'd be a last desperate search for a cure or fix for the extinction of mankind. It's up to you the Author about whether you want this to succeed. [Answer] A religious movement might decide that the global infertility is the punishment of God for the evil ways of them, and accordingly decide that it must be God's will that they are destroyed. [Answer] War, by its Clausewitzian definition, is the use of force to compel our enemy to do our will. This definition, its limitations and faults aside, hints at two primitives: the means (of force), and our will. Of these two primitives, means are variable, not only through the ages (as seen with the development of weapon systems), but also during the course of the conflict (reflecting casualties), and thus represent the changing character of war (the way we prosecute war). Will, on the other hand, represents the unchanging nature of war, being as it is an expression of human nature. The dystopian scenario of the question purely addresses means – the loss of fertility predicates a reduction in manpower, an issue for the character of war, provided that the existing paradigm of increasing battlefield automation is somehow abandoned and WMD are somehow discounted. This character of war will change correspondingly to reflect the means change, but the nature thereof will remain constant, as long as human nature remains unchanged. It is therefore not a question of whether war will be possible in such a scenario, but rather how such a war will be fought. The ‘why’ or ‘origin’ question is thus the same as for any war – a query addressed by a host of academics (Geoff Blainey, Michael Howard, Bertrand Russell, Anatol Rappoport, etc.), using a variety of models and tools (Game Theory, etc.). But please note :this is not to suggest that war in such a scenario is guaranteed – but rather to show that war is possible in any scenario, whenever certain conditions are met. This leads to the question – what are those conditions (of human nature), specifically those required for a major war? A handy analogy to aid the conceptualisation is of a playful ‘dust devil’, building into a tornado when the correct meteorological conditions are present. The first prerequisite is almost self-explanatory: major conflicts require major belligerents, and the more belligerents there are, (in the form of alliance systems, or self-identifying camps), the greater the likelihood of the conflict outgrowing time and geographical realities of the origin. Even big wars start small, just as every tornado starts life as a ‘dust devil’. The second prerequisite is a mental construct: a structure of fairness. Wars are either fought to maintain the status quo, or to change it. Given that fairness is subjective, those who feel that the status quo is fair, will fight to maintain it (or improve it to be more ‘fair’). Those who experience the status quo as unfair, will seek cause to change it. For a war to occur in the scenario described, my suggestion would be to supplement the loss of manpower by automation (including drones and the likes in combat zones), thus addressing the implied reduction of means. To address the will (assuming that the dystopia is brought about purely by the loss of fertility, and not some additional external accelerant), there is nothing to suggest that existing conflicts will be concluded or abandoned, purely on the basis thereof – in short, [insert name of least-favourite world leader here] will not all of a sudden abandon [insert casus belli here], just because nobody is having babies. However, should you feel that a brand new war is needed for a brand new threat to our existence, the will primitive is auto-diagnosed by a perception of fairness, (or the lack thereof). Scarce and in-demand resources (such as fertility) is fertile ground (pardon the pun), for perceptions on fairness to develop. By having major players coalesce into two opposing camps, the rest should be a walk in the park. Sorry… [Answer] > > Nothing binds a people to their leader like a common enemy. Voters > don't change governments during war. Harvey Fierstein > > > Read more at: <https://www.brainyquote.com/authors/harvey_fierstein> A sense of impending doom and hopelessness would make the citizenry unproductive at best and hard to govern / chaotic at worst. An outside enemy will unite the people in a cause, taking their minds off the existential threat of extinction. [Answer] In the face of extinction, I would imagine that many people would be in denial. People in denial might lash out against those who challenge their self-deceptions. That is, of course, not particularly rational. But, in this case the aggressors would be protecting their own wishful perceptions, as opposed to anything planted firmly in reality. Sadly, I think that that sort of protectiveness over perceptions is quite common in people. In one extreme case, I remember reading an article about a school in (I think) Russia, where a teacher was accused of sexually molesting their students. The parents were furious... at the accuser, for suggesting that this particular community was as bad as outsiders made them out to be. I wish I could cite the article, but I don't remember the name off the top of my head, and the details aren't particularly important to my point anyway. More generally, it is well known that people who are in distress, and especially who lack feelings of security/stability in their lives (which people in the situation that you described certainly would) have a tendency towards risk-taking behavior (which war certainly is). The distraction of war might be worth the trouble of going to war. People come up with a lot of stories for why they lash out, but I think that those are mostly just things to tell other people. Or, even when they are legit, the reasons tend to fall back on this: when they feel insecure, people get more aggressive. For this reason, I cynically think that the situation that you describe would likely lead to conflict. The real challenge is deciding what excuses people come up with for becoming violent, how quickly do those ideas (excuses) spread, etcetera. [Answer] Disagreements in how far people are willing to go to create new humans could create conflict. Otherwise, I don't see why the usual things wouldn't apply. People might be of the opinion that lives are precious, but not their lives, or not as precious as a cause. Much as today. Some might be of the opinion that they are entitled to supress and control populations for the greater good. Cloning might be an option to save humanity. Some might see this as bad. Maybe they are right to? Maybe clone soldiers are dispensable and "real" humans are not? ]
[Question] [ You are an dishonest time-traveler from the year 3100. You would like to travel back to our present day, and with your advanced technology, convince us that you are a god. You have unlimited energy, nigh-magical future tech, and few morals. How would you make most of the industrial, fairly educated people of today's world believe that you are a deity rather than a fraud or time traveling swindler? [Answer] VR "Afterlife" First, start a religion. This should be pretty trivial - you just need a few miracles that aren't currently explainable. Now you have some followers. Implant nanotech into your followers (or possibly just everyone?) that reads and records their mind. When they die, create a simulacrum of their existence that thinks and acts like they do. Put this into your version of the afterlife, which in reality is a massive VR server running that gives all your simulacrums, for the most part, whatever they want. Now here's the kicker: You can let people visit it before they die. You will need to dress things up to be all mystical and holy-like, but have a setup that will take one of your current/potential followers and let them visit the afterlife. They can literally talk to people who have moved on and received their heavenly reward. Rather than being a nebulous, unknowable heaven, you offer real, demonstrably, provable immortality. As a side bonus, since you have nanotech reading the brains of everyone you can data-mine them for useful information - the ultimate in insider trading and intelligence. Note: You probably don't want people to have to die before you can use this tactic, so you could create fake NPCs from a certain period of history. For example you could pick a "dead" religion and pretend that's you. That way you don't have to worry about simulating people who died before you can read them, but who your followers might still have known (parents/grandparents, and the like). [Answer] Here is the plan: First, incarnate not as a god, but a prophet. Gather a bunch of followers (seems not too difficult, considering your powers). Then make a very detailed prophecy of things to come (and to be acted out by yourself). What does happen when somebody claims to be prophet/ psychic/ 'the new shit' and has not got the weapons/ political power/ historical justification, like some contemporary organizations? The skeptics show up. Get invited by James Randi / Richard Dawkins etc. for a SMALL show of abilities which from today's viewpoint, are impossible (levitate, faith healing of broken arm etc.). Let them examine this closely. Let the media spread your fame. Then you can levitate into space, recorded by dozens of amateur and professional filmers, but not before you hold a speech to the masses, about the coming of the deity in the year \_\_\_\_. This date can be anything from 1/2 year to 50 years later. In the year \_\_\_\_, you literally descended onto earth from space, act like you 'predicted' earlier, this time you will not need to hold back with your abilities. A kind of mission statement (the mission can then be fulfilled) would be useful too. Something along the lines ' I've come to exterminate every racoon on earth, as they are truly a source of elemental evil...' EDIT / FURTHER thoughts: From your question: > > You have unlimited energy, nigh-magical future tech > > > It depends on the 'nigh-magical' but what exactly is the observable difference from 'unlimited energy' to a deity? I will not cite [this](http://tvtropes.org/pmwiki/pmwiki.php/Main/ClarkesThirdLaw) worn out phrase, but it does apply here. In short: If you have (near) omnipotence, is it wrong to call yourself divine? [Answer] The difficulty in this question is not convincing people you are a god. You don't need to try to do that, just exist and some kooks will start thinking that. The difficulty is in trying to get 'most people' to believe the same thing. Now, in the modern liberal tolerant world, that is hard - no sooner when some people start believing, would lots of people start believing the opposite to just oppose the first group. Most people's default response would be to not give a damn. So you basically need to get up in their face, and roll back the clock on the world to a time when people could be mostly homogeneous in their beliefs. Step 1: Control the flow of information. Let's say you brought back a nice little computer that could break RSA encryption, and a very clever and complicated little virus. Bam, the internet is yours. Start to subtly isolate and filter content. You don't want any way for opposition to organise against you. When people see you on the news and google 'is this dude for real', they'll see only what you want them to see. Step 2: Be impossible to ignore. Large scale international miracles are the best. It'll depend on what you have available, of course. Can you draw text to every person on the planet's retinas simultaneously? Can you make people unable to sleep until they make a personal verbal statement of their belief in you? Can you write your name on the moon, or the surface of the sun? Step 3: Discredit the opposition. Obviously step 1 is not going to be perfect. So you are going to have to make steps so that the vast majority of people hate, hate, haaate whatever opposition manages to organise themselves against you. You can do this with guilt by association (this bad bad guy disbelieves, are you sure these disbelievers aren't bad either?) or by producing false flag attacks. You might even take a page from 1984 and generate your own opposition. Like have a cult be created that still thing you are a diety, but an evil diety. That would help change the terms of any opposition into a win-win situation, and make your enemies easier to monitor and easily to disparage. Also, these days, it's better for a would-be god to never physically appear. Then there's no one for them to want to kill or hate, just a concept or a voice that you control from behind the curtain. If you are vague enough, a lot of religious people can be made to convince themselves they already believe in you. [Answer] Just use your super crazy tech to do some "miracles" and claim to be a god, perhaps choose a god in particular and make everyone think you are it (make others call you Zeus, fornicate with anything that moves and electrify to death anyone looking at you funny). Demand people to do your bidding and offerings or they explode, and give some benefits to those that do as told. Make sure to make examples of those who would deny your godhood. If someone is allowed near, make sure you have some sort of force field in case of sneak attacks and make sure to check for any kind of poisons. After a while those who would try to kill you would see the futility and accept you as some sort of god, if only for how hard it is to kill you. [Answer] Who Doesn't Love a Second Coming? You've got a time machine, and people a few thousand years ago may have been a lot easier to convince than they are now. Go back to some arbitrary time and show off some miraculous behavior. Build up an opposition (this part is important), and rally your troops against them. Introduce a vaccine to your true believers through a ritual of some sort shortly before some climactic conflict, then unleash a biological plague on your enemies, so when your side wakes up, they find the opposition decimated and winning seems miraculous. Have monuments made to you. Introduce stone-cutting techniques that the natives couldn't possibly have and more importantly couldn't replicate. Make them sacred so that no one would ever write about them (better yet, pick a culture that hasn't developed writing), and take them with you when you 'ascend to the heavens' or travel to the current day. Have a sacred cave that belongs to you, and have it packed with items that describe geometric principals or crop rotation or other things mankind didn't discover for 1000 years. Have extremely accurate drawings and carvings of you included. Make sure none of it has intrinsic value like gold or jade. Have it sealed and cursed. Lay traps for thieves. Ensure that it is in a location that won't be discovered for 1000 years. Or perhaps in some particular natural disaster. Predict the exact time and day and circumstances of your return. Have it be just after a huge natural disaster, and perform something that could even be called miraculous in today's jaded environment. Make sure that it is coincidentally televised, and make sure that you save a lot of people in the process. There will be very vocal skeptics. They will say, "If he is god X, why hasn't he done Y?" This is where your cave comes into play. If they come up with something you didn't think about, go back and put proof of Y in the cave. Never respond to the skeptics directly. Keep all of your public acts positive. Feed the world, introduce cheap desalinization, save the world. Go back to when your inconveniently vocal detractors were kids, and kill them in some sort of accident. Being as unscrupulous as you are, who cares about the consequences to the future time-line? The thing about the scientific method is that even with scientists, it is very hard to convince them of something when the overwhelming anecdotal evidence points the other way. There will be people strongly opposed to the prevailing belief in you, but deep in people's hearts, they will be unconvinced by any argument when your divinity is so obvious. Now, I'm not saying you should go for an Almighty figure, or claim to be Jesus or something. Be a pantheon god, because they were fallible. This is much easier to pull off. Of course, you'd be asked to explain why any of the other gods haven't returned, but like I said, never address such questions. Let your acts speak for you. Be aloof. Or be someone more enigmatic. Without doing the research and just going by memory, it seems that Quetzalcoatl might be easy to co-opt. [Answer] Gusk has an easy way to do it, but you don't have to go that far. People want to believe, which is why there are so many cults out there. The guy in Waco had his followers convinced that he was Jesus returned, and he didn't have any special powers or abilities. Smiting people could help establish his power, but it would also cause rebellion against him, especially with all the skeptics around. Eventually someone would get a lucky shot in and he'd be a dead god. Best to leave the smiting as a last resort and just show off some power. Stay mysterious. Between now and 3100 there will probably be a few cults, just steal from their playbooks, and he'll start to pick up followers. Stop a natural disasters... You'll never get 100% of the people. The idea is to pick up enough to have some political power and money. [Answer] ## Use the same ways most people are convinced of godhood. Prophecy You're a time-traveller. Download some history off the interwebs and, occasionally, start speaking in tongues and, afterwards, divulge information on some event or other. Keep it mysterious enough that no one can act on it... For example, Germanwings flight 9525 could be "A guardian betrays! A flight, the earth reclaims!" When someone asks why you cannot be more specific, say that "It is not for you to question. Be satisfied, or begone." Of course you might accidentally change history Cure the Sick This is a big one. People will often do a lot to cure their own illness, or a loved one's. Bring some cancer-fighting drugs and slip it into someone's food before the great magic act. If you cure someone's hopeless illness, you've probably got a follower. Perform Miscellaneous Miracles Find a good spot to dig a well with some 32nd-century scanner. Create loud booming noises with a stealthy drone. Point at a tree and watch as it erupts in flame (due to energy projection from said drone). Separate salt water into salt and water. Create a YouTube post that only gets intelligent comments. You don't have to convince everybody. Sure, some people will see your claim and laugh. But anybody who says you're a time-travelling charlatan from the year 3100 is going to generate just as many giggles. [Answer] No need to convince them... If you're dishonest enough, you also may be disrespectful enough to override the annoying glitch called "free will". With your "indistinguishable from magic" technology, reprogram your target organisms' neural circuitry to worship you as a god. They will be your loyal subjects no matter how illogical it is to do so. [Answer] Bring lots of tech. Tech that doesn't look like tech. Mostly nanomachines, as they can be renewable. Do lots of pointing at things, and making those things do stuff without you appearing to physically touch them at all. Turn on lights, open knob-handled doors, make plants wilt, smite naysayers. That kind of thing. Stuff we don't yet have the tech to do. It will be very easy to convince the fairly educated gullible, and there are lots and lots of gullible. It is VERY easy to persuade someone away from religion; you presently work miracles, and other gods are not around to defend themselves. [Answer] *Convince everyone personally.* You don't have to do this in person yourself, of course: that's what your army of AI-controlled clones is for‡. Every person on the planet can have a personal conversation with You As God, and every clone of you will be able to perform miracles sufficient to persuade whoever it's currently talking to. Said miracles may include smiting, seduction, using the water/wine miracle to get drunk with someone, creating a golden statue from nothing, or a simple conversation about philosophy. You don't even need to be consistent. Even if all of the mortals start comparing notes about you, it doesn't matter: they'll be persuaded that you're a god, even if you say completely contradictory things to different people – you'll just be an inconsistent god. And if various people manage to convince themselves later that you're a hallucination/con-man/alien, just have another clone drop by with further proof of your divinity. You'll end up with a few people who are stark raving mad and/or cripplingly paranoid, but as long as most of the planet is convinced that you're a god, surely that's good enough? The important part here is to make sure that nobody can ignore you. On a personal note, there are plenty of things I've filed as "that's weird, but ultimately irrelevant to me; it could be a god or simply something we don't know enough about yet." But if you're visiting people in person, repeatedly, with nigh-indisputable "miracles," then they can't just dismiss you as irrelevant. ‡: The AI is, of course, both immensely powerful and friendly to you, and will do what you intend, rather than merely what you ask for. All of that silly "rebellious AI" nonsense got taken care of in the Great Reprogramming in the year 2934. [Answer] Fake someone else's second coming Hello, I am... * Jesus. * Allah. * The Buddha. * Pick a Hindu God. * Steve. Remember before I died, I said I'd be back? It's documented. I am God. * The Prophet. I was prophesying myself. * Hercules, Achilles, some son of the gods. I've been hanging out in constellation form. * Grandpa. I discovered Immortality. Back from the afterlife. * Ozymandias, the pharaoh, child of the gods, now in god form. As predicted. * A dead pop star. Some people already thought I was God. [Answer] In the present day, it's probably going to be a lot harder to convince people than you might think. After all you, a person in the present day, are considering time travel and highly advanced science as a way of faking being a deity. So what's stopping someone else from doing the exact same thing as an explanation? It isn't just our understanding of science, but our fiction that makes people less inclined to immediately jump to the deity explanation. ]
[Question] [ I'm creating a planet, and I want it to be: * A windy place, with ocean everywhere (like the earth) * The same pressure & composition at sea level (like the earth) * Only one biome: A beach. The entire world would be a beach; no matter what land you're on, it's a beach. Is this possible? If not, what are some alternatives? [Answer] > > thin, sand shorelines, all across the globe > > > Sand is not a primary rock: it forms by disintegration either of another rock or other hard substances, like shells, glass, etc. That apart, sand needs a substrate on which it can deposit. Only for the above reasons, you cannot strictly have what you describe: you will need to have at least some other formation which is eroded to produce the sand and on which the sand itself rests. [Answer] # Old: Your world is old and mostly shallow ocean. There is little surface geological activity. Any land there once was eroded away millennia ago. Ocean currents and wind occasionally stir up the sandy sediment that comprises the sea floor. Those beaches are sand bars that are kicked up until wave and wind action erode them away to nothing. This is rather like the [coral reef world](https://worldbuilding.stackexchange.com/questions/201259/possible-reef-world) proposed in some other questions. [Answer] I've read that [something like 70% of Earth's oxygen production is by oceanic photosynthesis](https://oceanservice.noaa.gov/facts/ocean-oxygen.html#:%7E:text=At%20least%20half%20of%20Earth%27s,Earth%20comes%20from%20the%20ocean.) (phytoplankton, cyanobacteria, seaweed). There's no reason this couldn't happen on your beach planet. However, as @L.Dutch points out, sand has to come from somewhere. On Earth, sand beaches are usually populated by material carried down by a river, and coastlines with a long way between significant rivers (like much of the coast near the Oregon/California border) tend to have cliffs with their feet in the surf, rather than luxuriant beaches, while others that are prone to very heavy weather (like the southwestern coast of England and Wales) are more likely to have "shingle" -- cobble rock, averaging the size of a fist -- rather than sand. This also varies depending on the rock type at the coast -- for instance, basalt, as on Hawaiian and California/Oregon/Washington coast, vs. sedimentary rocks as found on most of Great Britain's coastline -- but the bottom line is, if you don't have a source of sand, you won't have what we usually think of as beaches, and if you don't have highlands and rivers, your only reasonable source of sand is direct erosion of rock like the magma rocks of Hawaii, which tend to product black, glassy sand rather than white or tan "beach" sand. The only alternative I can see is coral sand, which forms on atolls. The problem with this is that in order to rise above the ocean surface, an atoll needs to have formed on a structure that can rise relative to the ocean, or persist long enough for the ocean level to drop (which likely won't happen on a planet that's all ocean and beach). [Answer] # Yes, if the sand is alive. Normally, non sand biomes would form. But, if the land is alive, then the sand could just be dominant. Have the sand be a photosynthetic sort of plant that lucked on some unbeatable strategy during its evolution. Almost everywhere is covered in sand plants, which work as a giant organism to catch the sun and make the world sandy. # Have no continents. Your world has seas high enough that any land continents are covered. The only exceptions are mountains and volcano islands, where everyone lives. Everywhere is windy, and everyone can live on islands and island hop. [Answer] Ocean world, mountainous islands The crust of your planet has been very buzy. Because of the earthquakes, the surface of the planet looks like a chaotic washboard, mountain ranges everywhere, elongated over 1000km or more. There is also a lot of water on your planet, which results in a large ocean, with many, elongated islands. The habitable parts of these islands are the shores. Inland, the islands are vulcanic badlands. Instable grounds, just like the shores are. It is very difficult to build a house that will stand for years. People live on the beaches and a few kilometers up the mountain. When a tsunami comes, they use special roads and elevators to evacuate. Sand from friction The sand originates from friction: geologic activity over long periods, with crust plates sometimes fragmenting in thousands of pieces, or crashing brutally. This has formed loads of loose sand and pebbles, left on the ocean floor, or bulged upward with another collision. Sometimes, the ocean floor will suddenly rise, locally. On your planet that happens very frequently. Every year, new islands are formed. Cause: tidal forces The cause of all this rumble: your planet got a new moon, a hundred million years ago. It suddenly appeared, then it stayed.. its orbit is elliptical and twice per month, a varying region will be subject to extreme tidal forces. Not only water goes up, loose parts of the planet crust move along too. Big Moon days Very inconvenient planet for its inhabitants.. but its Big Moon days draw lots of tourists ! Most tsunami's are quite predictable and seem to be an attraction, rather than a deterrence. The sounds.. it is a thrill to stay on this planet for a few weeks. Backpackers love the outrageous nature. A beautiful view, all these young, pointy and sometimes smoking mountain ranges everywhere.. the lava, the geysers.. And the beaches, of course. [Answer] Everybody mentions that sand can't form without being weathered from a primary quartz-bearing igneous rock. That's very true! But there is biogenic silica--and it actually solves both problems. Not only do [diatoms](https://en.wikipedia.org/wiki/Diatoms) form silica (quartz) shells, they're also the primary source of oxygen in the modern atmosphere. It's easy to conceive of a world in which diatoms evolved to be much bigger (sand-grain-sized), forming coarse diatomite beaches instead of the fine diatomaceous earth we're used to. [Answer] An almost-water world. Yes, it's possible. The oxygen is no problem at all. Single-celled photosynthetic organisms in the oceans here on Earth generate considerably over half of our oxygen. The "beach, everywhere" aspect is harder. Plate tectonics as on Earth will always throw up mountains. But a planet with so much water that only the highest of volcanically formed mountains rise only slightly above the surface, is possible. (Using one measure of height, the tallest mountains on Earth are the island volcanoes). So almost all ocean, with a scattering of coral attols, and coral sand beaches. Realistically, there will probably be a few steep volcanic peaks (active or dormant), as well as a majority of attols surrounding slightly submerged extinct peaks. No visible continents. Continents like Zealandia may exist, but even more submerged. It's ocean-floor spreading across "hot spots" which thrown up ocean volcanoes and then takes them away from their lava source and support pressure, letting them gently submerge while coral grows upwards as they do. Altogether, not unlike Earth's Pacific, but everywhere. Almost a water world, but not quite. Incidentally, the impermanence of these places across geological spans of time, means that all terrestrial life you envisage will have to breed or seed in the oceans, and colonise dry land anew every generation. (Like palm crabs, or coconut palms with their floating seeds). [Answer] Yes, it is possible. All the sand you need can be formed by [parrot fish eating undersea corals and pooping out the skeletons as sand.](https://oceanservice.noaa.gov/facts/sand.html) All the oxygen you need can be produced by photosynthesis of ocean-borne algae. Your beaches do not have to be "different", they can be exactly like Earth beaches. The oceans can be full of plants, like Earth's oceans, and fish, including sharks, and mammals, like whales and dolphins. Or aquatic dinosaurs. You can have shellfish. Coral reefs. Crabs. Other scavengers of dead fish. In order to be "all beach everywhere", you probably need a pretty stable ocean level, and fairly small islands with very low elevation. ]
[Question] [ I'm trying to build up a set of weapons for an RPG system and I'm trying to make a semi-realistic system that tries to strike what I think is a good balance between complex enough for a semi-realistic set of rules while keeping those rules easy to understand. Right now, I'm looking at the two-handed hammer, something that would be unrealistic/impractical in our world. I always thought the Paladins from Warcraft III with those massive hammers were cool and wanted to have a two-handed hammer in my setting. I won't be using something quite as big as what you see the Paladins of Warcraft III using since those are a little overkill, but instead using some of the slightly more sensible two-handed hammers from World of Warcraft as an example/reference. Here's an image of the size of weapon I have in mind as the size of a typical two-handed hammer: [![typical two-handed hammer. Source: Wowhead](https://i.stack.imgur.com/0g16W.png)](https://i.stack.imgur.com/0g16W.png) In the setting I'm working on, I intend for these weapons to be wielded by people who are much stronger than humans of our world, through some combination of natural strength, training or magic, since such a weapon would be unwieldy in the hands of a normal human. I'm trying to think of what kind of situations such a weapon would be useful in, assuming they were used by those strong enough to wield them. A few thoughts come to mind; crushing armour by overwhelming force or clearing large numbers of brittle or frail opponents and maybe demolishing structures? This might also help. In my RPG, I plan to split physical damage into three types: slashing, piercing and bludgeoning with everything having different balances in defences between the three types. Some weapons will have multiple damage types through different attack types while some focus on one over the others. I see the two-handed hammer as being a highly specialized weapon where bludgeoning force is the best way to dispatch a foe. [Answer] # Slow, and heavily armoured foes. Sledge hammers and other sorts of two handed blunt weapons were not used a lot in war because people even in full plate armour could easily dodge such heavy weapons. So, you need an enemy that is mostly invulnerable against swords and arrows and such, and which isn't fast enough to dodge a slow and heavy weapon. Trolls? Giants? Siege equipment? Lots of options. [Answer] Giant hammers are super realistic and practical! Taken from my answer here: [Why would a regiment of soldiers be armed with giant warhammers instead of more conventional medieval weapons?](https://worldbuilding.stackexchange.com/questions/194382/why-would-a-regiment-of-soldiers-be-armed-with-giant-warhammers-instead-of-more/194423#194423) Lead mallets were a European favorite. I knew the archers at Agincourt had them but figured that they had them to pound in stakes, so used them to pound on knights later. But apparently these weapons were made in bulk for arming masses. Sometimes the masses armed themselves with the mallets for their own reasons. <https://willscommonplacebook.blogspot.com/2010/01/archers-mauls.html> > > Lead mallets were also used by other infantry. The Paris rioters that > broke into the Hôtel de Ville in 1382 seized so many lead mallets that > they became known as Maillotins, and as a result we have a useful > illustration of the weapon in an illumination of the revolt, above. > > > The first insurrection was that of the Paris mob, and was sparked off > by a costermonger who, when an official tried to levy a tax on the > fruit and vegetables he was selling, began to roar "Down with the > gabelle!" At this cry, the whole populace rose, ran to the > tax-collectors' houses and robbed and murdered them. Then, since the > mob was unarmed, one of their number led them to the Chatelet where > Bertrand de Guesclin, a former High Constable, had stored 3,000 > lead-tipped cudgels in preparation for a battle which was to have been > fought against the English. The rabble used axes to break their way > into the tower where these cudgels or mallets (in French, maillets) > were kept and, arming themselves, set forth in all directions to rob > the houses of the King's representatives and in many cases to murder > them. > > > This site has awesome stuff on lead hammers as used in battle. Also some fine Chaucerian English descriptions of "awesome thwacks" and the like. --- I think in addition to being cheap to make, easy to store without fear of rot or rust, and free to maintain, huge hammers can be used effectively with a minimum of training. Civilians pressed into service would be familiar with swinging axes and hammers. But your folks train with the hammer so that would be less of an advantage. So why would the fact that they are inexpensive be helpful? I can think of a reason. These guys go thru a lot of them. Your soldiers are so strong that they routinely break hammers in use. A soldier might go thru 4 or 5 in one battle. That would not be sustainable with swords, but there are a lot of spare hammers so it is ok. If they win, a couple of them will go around with big baskets and collect the broken off hammer heads for reuse. [Answer] Doors Hammers could be used by the fantasy equivalent of a SWAT team or fire department breaking into a building. If the door is bolted at the center an enforcer ram would work better, and if the doors are wooden an axe might work better, so maybe the doors are also bolted at the top and bottom and are reinforced with metal. Also cement elementals. [Answer] ### Most situations... Two-handed maces have a lot of mass compared to other types of weapons. Kinetic energy is governed by $KE$ = $1/2$$\m\$$v^2$, so in theory it's better to use a lighter weapon that you can move more quickly. In practice, there are are physical and limits to how quickly a person's arm can move: a golf ball weighs more than a pebble, but most people are strong enough they have no difficulty throwing a golf ball as quickly as a pebble. Fighting style aside, energetically speaking it's better to use a weapon that you can move at or near the limits set by your limbs. For similar reasons, it's easier to block a lighter weapon. A fighter with a shield turn away a sword strike (however strong the foe) without too much effort because the sword is lighter and therefore has less $KE$. A mace or maul swung by a burly foe will take more effort to block, and sufficiently strong foes or repeated strikes will damage the shield or armor. Attacks with heavier weapons will be slower and can be dodged, and with sufficiently strong foes this will be the only practical option - football players may block a charging linebacker, but they won't go toe-to-toe with a car. Since the strongest foes will move heavy weapons at similar speeds to light weapons, this speed advantage diminishes as strength scales up. In the extreme, it's like fighting somebody wielding a rapier, but the defender is only able to dodge. ### ...except maybe in contests against an equal foe When pitted against an equally-superhuman foe, this advantage diminishes. Staggering their foe with the force of their attacks will not work, so superhuman fighters will focus on the weak link: armor. A superhuman fighter with a sharp sword can shear through plate armor like it's leather. While comparatively-fragile armor won't provide much resistance against a blunt weapon, the beefy fighter's physicality provides more defense than the armor, and the advantage of a more massive weapon may diminish. Ultimately, it might depend on the weapon's material. A fighter who can shear through plate with a sword will break or dull a lot of non-magically-reinforced swords. A maul or two-handed hammer may distort with repeated blows but will still remain functional up until it breaks. [Answer] If we're talking raw damage? Nearly everything. Armored foes can do nothing against the kinetic forces generated from such a weapon. At best they'll walk away(try to anyway) with a broken bone or concussion, at worst we're talking ruptured organs and internal bleeding. Not a great way to go. Just about the only thing that'll be able to resist or only bruise from a heavy blunt weapon is an organism or enemy with huge amounts of padding, like walruses or whales or very fat ogre or armour that'd rival the onion armour of dark souls with its supple girth. Feasibility though? You'll not get too much in the way of battle effectiveness out of it. Most mobile enemies will be able to dodge its slow swing, and if it does indeed connect it'll probably only be due to luck or incompetence on part of the enemy. Honestly if spears or arrows or tripping weren't a thing you'll get more use out of it on a battlefield by holding onto its handle and spinning a path around the battlefield like some sort of mad man. Hopefully the chaos you'll create(if you have enough space to get it spinning and can handle the nausea) will take out enough enemies to warrant the tactic. If you can get close enough to a shield wall to use it you may also be able to break through their defenses but you'll open yourself up to being surrounded and whatever surprise shanking awaits you from the broken up group. I suggest taking hammers to fortifications or barriers and foes too heavily armoured to move with much agility, as other answers have pointed out. [Answer] "Bec de Corbin" (Crow's beak) is a historical [example](https://www.pinterest.fr/pin/286049013812861733/): [![enter image description here](https://i.stack.imgur.com/mieNT.jpg)](https://i.stack.imgur.com/mieNT.jpg) It's a cross between a halberd and a hammer. There's a spike at the business end so it can be used like a spear, a hammer on one side to smash foes in armor, and a sharp beak on the other side to pierce through the armor with maximum violence and then impale its owner. The hammer in the picture has two identical sides, which means it lacks versatility. This is a rather extreme example of making the two sides very different, so the user has more options. This one would deal piercing damage on one side, and bludgeoning on the other. This would work nicely against tough skinned fantasy monsters too, since a hit with the beak will penetrate a hard target much deeper than a thrust with a sword, which is the point of this weapon. It will also go over a shield. In order to be fast, it isn't too heavy. If the armor is struck in a vulnerable place like a joint, the fighter inside could be fine, but the armor could bend out of shape and restrict his movements, or the visor would no longer open, etc. [Answer] Bashing Iron Golems The hammers are for hitting Iron golems very hard. The goal is not to break the golem in half, but to warp the armor plates so the Golem has difficulty moving. For example you hit the knee so when it tries to move, the shin and thigh plates that meet at the joint grind into each other. ]
[Question] [ I decided to create a robot swordsman for my story and I would like to know exactly what are the different advantages he would possess over biological opponents. Also what design choices would make him a better swordsman? The only restrictions I have with this character are that he must be humanoid and the swords he uses aren't attached to his body. What kind of design would he have? What inhuman characteristics would aid in swordsmanship? What kind of foul play can he add to his design to punish cheating opponents? What upgrades could make him superior to a human? How would his swordplay be different from a humans? What would be the full extent of his abilities? [![Koji concept art from Alexander Snow](https://i.stack.imgur.com/E1GVD.jpg)](https://i.stack.imgur.com/E1GVD.jpg) Possibly the remains of a gladiatorial robot (for entertainment against other robots like in Real Steel) this android was recovered by a wealthy company, who decided to use the robot as a bodyguard of sorts. His original design and programming where kept mostly the same but he also received some upgrades. The crude materials he was made of were replaced, his processors were upgraded with the best hard- and software available. (since this robot is in a futuristic setting lets not worry too much about the technology.) So far his personality is that of a charismatic and noble warrior. He overwhelms his foes and gives them handicaps (possibly to mock them). For example if his opponent has an injured leg he will stop using the same leg. He plays fair so to speak, but whenever an opponent cheats he will cheat back. He has many tricks up his sleeve due to his gladiatorial background. He is occasionally used as a training robot, so he knows to go easy on human opponents. [![enter image description here](https://i.stack.imgur.com/tOPlO.jpg)](https://i.stack.imgur.com/tOPlO.jpg) What I'm looking for is what cheats, dirty tricks and upgrades would make a robot fencer overpowered, despite bringing a sword to a gunfight. If you have questions simply comment and editing shall ensue. ps (please avoid putting my question on hold) [Answer] The advantages of a robot swordsman is a diffused set of vital functions. Something I point out a lot is that humans aren't really designed for combat, a especially considering the number of spots on our body that would mean instant death, or lifelong incapacitation. A robot, on the other metal hand, does not need suffer from this. Redundancies would go a long way towards making a robot all but unbeatable. (I'm assuming for this context that the humans have swords which can cut through the robot's metal body.) Take, for instance, a question of handedness. A robot could use his right hand as easily as his left when it comes to swordplay, but only an ambidextrous swordsmaster would claim the same ability. So a robot would be fine losing a hand in combat to deliver a crippling blow, as the robot would simply switch hands. Similarly with most cuts. Stab a man high in the chest and you're bound to hit something vital, be it the heart or lungs, and it's quite difficult to fight with that kind of injury. A robot doesn't need lungs, and with integrated power sources throughout it's body, one stab will hardly cripple it. And, of course, any injury made to a robot can be repaired by engineers in a matter of hours. A human would need days of rest, and is incapable of recovering from certain wounds, such as regrowing limbs. [Answer] It is not a killing machine. It is a fencing master. If the goal of the maker were to make a killing machine he would not make a swordsman. But that is not the goal: this robot prioritizes fair play and a level playing field over victory. It is bound by rules. It is a fencing robot. The robot must therefore be defeatable by another swordsman. This is not a trivial attribute. It is not easy to hurt a machine with a sword. The swordsman robot has built in spots where a strike equals a win. Fortunately fencing as a sport already has that - a heart patch on the fencing suit. Your robot might have more than just a heart patch - places where an allowed strike equals a win and places where a strike equals a debility (noted example - a leg out of commission). If the robot is defeated it congratulates its opponent, concedes and leaves the field. Likewise the robot will stop short of killing its opponent, preferring him or her to yield. This is how the Three Musketeers fought - rule bound and the object being to defeat your opponent and make him yield (then break his sword!); killing him was an occasional but undesired outcome. Cheating need not be punished. Cheating does not help. If kicking is against the robot's rules then if your robot is kicked, it will not help its opponent. The robot will verbally notify its opponent that the move is disallowed. A surprise attack will be considered notification that a fight is desired. But the robot is seriously strong and basically impervious to harm. Its maker wanted it to be able to fight match after match, indefinitely. Your robot was actually created as an instructional tool. This is made evident because the humiliation it causes its opponent is due to its running commentary and advice as regards technique. It will criticize but it also compliments good technique. Also if it wins too fast it will invite its opponent to try again. The opponent so invited might not realize the robot considers him or her to have lost. To defeat it you must play by its rules; otherwise the best you can hope for is to avoid it. This is frightening to its opponents. It is profoundly irritating to its allies who want it to be a war machine. [Answer] For a battlefield robot that fights with swords, a humanoid frame is actually what you would try to avoid. Your robot will want to be able to create a stable fighting platform wherever it goes, so it will likely have a low center of gravity and multiple legs. Bonus points for being able to climb walls and so on, Douglas Fairbanks Jr will have nothing on this. If each leg ends in an actuator that allows it to wield a sword at the same time, then it could move and fight in any direction. Depending on the design, it might also be able to use two swords at once, or fight "Italian" style with a sword and dagger or cloak. [![enter image description here](https://i.stack.imgur.com/KpH1h.jpg)](https://i.stack.imgur.com/KpH1h.jpg) Wouldn't giving this a sword be a great idea? [![enter image description here](https://i.stack.imgur.com/8BXON.jpg)](https://i.stack.imgur.com/8BXON.jpg) Italian style fencing Given the desire for all terrain movement and possible climbing, the leg joints will not move in the same manner as human arm or leg joints, so trying to figure out what strike or parry is being used will be difficult. With fast and effective articulation in manners that no human could match, it will also be able to create systems of strikes and parries that no human could do, and it would have the inhuman reflexes to be able to throw the sword in the air and catch it with a different limb, or accurately pass the sword to a fellow swords-robot. [![enter image description here](https://i.stack.imgur.com/1nie7.jpg)](https://i.stack.imgur.com/1nie7.jpg) Replace the wheels with hands and the six legged robot wins Of course, in the real world swords were rapidly overtaken by pole arms and smashing weapons to provide leverage and striking power that a sword could not, and your robot will be opposed by a huge arsenal of medieval weapons invented to deal with armoured knights. Even enemy robots wielding halberds will be able to defeat a swords wielding robot, and robot archers could span steel crossbows with over 1200 lbs of draw weight with ease. [![enter image description here](https://i.stack.imgur.com/60jXZ.jpg)](https://i.stack.imgur.com/60jXZ.jpg) Fighting with edged weapons is like this [Answer] Swordman has to be fast. Memory alloys are slow; they might be used to make his body/armor self-repair the dents. Does "Actuators" mean electric motors, like in modern robots? They are precise, but I think you will face serious tradeoff between speed and fragility here -- fast-spinning gears will be damaged by any serious jolt, and if the motion is forcefully resisted (as in parrying), the electric motor can burn out. Hydrolics are more reliable (and commonly used in construction equipment), but I am not sure of their speed. Artificial muscles are in prototype stage in RL, so their full potential is stuff of sci-fi, and you can imagine them any way you want. Like human muscles, they will be vulnerable to cuts and tears. I am actully thinking an idea of a linear motor: basically a heavy piece of iron pushed up/down a shaft by electromagnets placed around it. It should be fast, simple and resistant to jolts. In any case, your swordsman can make himself stronger and a faster at will (at the cost of battery charge) Addition on swordplay: a mechanic swordman can spin a sword (like general Griveous in Star War prequels). This will be a major advantage vs. another swordman, both on offence and defense, at least vs. a sword. A chain or sturdy polearm can stop the spinning sword, but that leaves wielder open to conventional sword attacks. I would recommend a curved sword to keep it from getting caught when spun. [Answer] I'd say that its biggest advantage is the ability to split its attention perfectly. Humans can talk about multitasking, but we're not really good at it. The more we split our attention, the less time we give to any one task. Computers - and by extension, Robots - don't have that problem. Multi-core processing means that when they split their attention, they're able to process two streams of information simultaneously. For example, where a human using two swords will often only move one at a time, both together, or have to rely on a well practiced pattern, a machine could truly move them independently, responding in real time to changing conditions without aborting anything they're doing. They would also have lower limitations on perception. They would be able to track more that's going on around them than just the opponent's weapon in front of them, making them harder to misdirect and surprise. There's also nothing to say that they would only have one set of "eyes", so not only would having 360 vision be on the table, but so would, for instance, having something on their knuckle to better see exactly where their blade is going. And again, they can consider this all simultaneously with their physical control. There are even ways that this strength can be used as a weakness. For instance, one of the recent technological breakthroughs was a robot that could process input on its skin. The hurdle used to be that it was just too much data to deal with, but by only processing what information changes (the way humans do) it could handle it. Taking that further, a Robot using its expanded senses that's suddenly presented with too much information might find their ability to process complex thought diminished - the same way video compression gets messy when trying to handle snow. Still, one-on-one, or even several on one, a robot would stand a much better chance than a human in its place. Just be careful of confetti cannons. [Answer] * What is the rest of the setting like? How are they fighting? Vital questions. * Swordsmen exist in the fist place because of a mixture of reasons relating to limitations and trying to overcome them. For example the ideal environment for a swordsmen is 1v1 fight with no to light armor. Heavy armor changes the equation, mounted combat, shield + spear vs sword..etc. So the fist choice of creating a robot swordsmen is an odd choice to see the say. * However if this is an entertainment robot then we can assume that it was made for a certain level of sports, not combat. For example modern Olympic fencing is about a first touch even if you get hit, for a HEMA that is suicide. So the fighting style of the robot would basically be something like movie style fighting with big wide arcs, clashing swords, telegraphing moves...etc with the sole purpose of style and looks over simple practical killer moves. So would you like something like that or it get a different combat programming in the retrofitting? Anyway assuming it was changed with the purpose of actual combat and, for whatever stupid reason, it was not given actual proper modern weapons and armor what can we expect? * Reach. Simply put the ability of a spear to hit a sword, most of the time, before the sword can hit the spear is a huge advantage in fighting. So give the thing extended arms and level the playing field. Honestly a huge game changer. * Disarms won't work. Simple as that. * Grappling and bunching. Oh boy. Actual HEMA is about getting into a fight and winning it as fast as possible. So even a master swordsmen would punch, kick, and throw sand in your face if they can. Fights are dirty business survival is good enough. So would you be willing to incorporate that? They can also grab an opponents sword mid cut. * Little fear being hit means that it would have a more offensive style against certain opponents while at the same time their opponents would be forced to think of a way to actually deal damage to it. * Being a robot it would be able to fight without an arm and a leg. That means that it won't tire or lose blood, it means that small cuts and thrusts won't work. So against a human the simplest method is letting them attack and attack and attack until they simply tire out. Same with letting their arm get chopped off, assuming the opponent has a weapon capable of that, in order to deliver a killing blow. They can change a hand but we can't. * Inhuman movements. Think about how limited our arms are. I can't strike at my back without turning my body. Well. This is a robot. So if it has arms capable of delivering a strike. That is quite a game changer. It means that no matter the angle you still can strike effectively. * Perfect vision in armor. Again we don't know what the are fighting against. But knights had very limited armor and that meant they either sacrificed a bit of protection or vision. So not only can't be armored without sacrificing vision. It also means They can see a hit coming at their back. No blind spots at all. * Lastly If you provide more context about the world and the expected opponents it would be better. But the limitation of tech is a huge aspect here. Does it have superhuman reflexes? Can it face swords capable of cutting throw it's armor? Are shields a thing? Are firearms a thing? I personally don't get the whole noble swordsman thing tbh. Fighting is always about winning. So why would you make a bodyguard that limits itself if the opponent is limited? "All warfare is based on deception" as they say. [Answer] If we aren't worried about technology, the swordsman could be nothing but a projection of a galaxy-sized dark-matter intelligence whose arrow of time is disconnected from ours. The position of its projection in our 4 dimensional 'brane is arbitrary, and its actions and decisions are disconnected from our causal framework. Its advantages would then be near omnipotence at human scales, and its disadvantages would be not understanding us very well (like we don't understand ants). --- If we downgrade technology sufficiently, a humanoid robot like that using a sword is going to be a novelty. They are entertainment devices, not combatants. As a bodyguard, that would then be its primary purpose. To look flashy. Something like that isn't for serious security, it is to draw the attention of those who want to attack away from the real security. It being a swordsman would be part of the show. A sword isn't a serious weapon, no matter how strong the wielder is, in the era of modern weaponry, let alone a future where you can build a reasonably competent robot. So it, and its ability to fight, is a distraction. It fighting "honorably" makes perfect sense, because it fighting isn't part of the real security other than a distraction. It is applying limited force, as actually blowing someone up because they are a potential isn't great legally or PR wise. But threatening them with a sword, and if they push harder injuring them, isn't as bad. The real security would be in the form of small, non-human form, semi-autonomous drones. And the Robot could act as a UI for the important person to interact with. If the person is a celebrity, there may be a constant swarm of press-drones nearby; the security drones would look like press drones, and would be authenticating them and ensuring they (or humans near the target) aren't armed with weapons. Low-grade incidents, like a protestor with a creme pie (whose chemical makeup is sampled before it gets close), are intercepted by the robot bodyguard. [Answer] ## Introduction A Robot is roughly made of it's physical body, it's actuators and it's electronic (perceiving unit + computing unit), all these things provide fast advantages. I will divide the advantages according to the part it derives from, let's start: ## Physical Body The physical body can be made of any craftable material ### Advantages * Material based: + higher tensile strength + higher shear strength + higher noth impact strength + and so on... * Design based: + A human leaks blood upon injury, also there is a psychological impact upon lossing a limb + In short robot does not care if a limb is lost, and while a human will be quickly unable to fight after lossing a limb a robot can go on forever. + a robot can have multiple arms and legs... + reach - When fighting opponents basically stand outside of eachothers reach and go into the opponents reach to attack. This is why when you learn for example a jab in boxing you will do a little step and jab than. - Why is that? Coz we are unable to react to an action done in our reach. You can teach that concept fairly easily hunting beginners hand's in stick fighting. An experienced fighter can judge the opponents reach due to body and weapon. But what if our robots arms can extend while striking? * Armor + A robot can have "perfect" armor due the material it is made of. + A robot could implement stuff like active armor used by tanks ### Disadvantages: * Oxidation / Corrosion + Material can break down due to oxidation, and while the human body does rebuild itself the whole time, a robot could only achieve this using something like nano-technology (this is far from my field of expertise so I can't really help you with that) * weight + Our robot is most likely really heavy, and will not be able to swim. It could walk underwater, but it would not be able to cross the oceans since without a boat, since the water pressure would crush it eventually. ### Summary Bascially a robot is way harder to cut than a human, also it is way more psychologically and physically resilent to injury. But a robot does need maintenance, new lubrication, and new fuel from time to time. While it can refill lube and fuel, repairing itself is only possible within limits. Also repairs are only duable if the correct equipement and material is available. A robot can fight with as many swords as it has arms, and it can gain another gamechanging advantage if it can extend it's weapons reach. ## Actuator Actuator is just an engineering term for "active" parts, like pistons, engines, and so on. So it is just the thing that is responsible that a part of your robot moves. Each motion is only possible due to one or multiple actuator responsible for it. The standard in current industry is using more actuators, since these as well as sensors are rather cheap in the current age, half a century ago motion transition was made using less actuators. See picture below (this is just a simple example, to show what this means): [![Actuator example](https://i.stack.imgur.com/3uqBC.png)](https://i.stack.imgur.com/3uqBC.png) ### Advantages * Strength + This is quite obvious, a machine is way stronger than a human. * Speed + see above ;) ### Disadvantages * Lubrication + if material with a tight fit rest long enough on each other they can weld onto eachother see: [galling](https://en.wikipedia.org/wiki/Galling>galling) + While it is possible to build really long lasting machines, lubrication will evantually fail. + Lubrication or loss of all lube will not cause the robot to immediatly cease to function, but it will do so given enough time. * Wear + All moving parts will wear down over time, even with lubrication. Meaning our robot will need spare parts / spare actuators over time. ### Summary Due to galling the robot will not like sitting deactivated in a corner for years. Also will our robot require spare parts. But it is way faster and stronger than a human can be. ## Electronics This are all sensors and electronic parts linked to perception. As well as robot behaviour in general (ai). ### Advantages * processing speed + The reaction speed to perceived information is limited due to the clock-time of the computing unit. Meaning a robot can process information faster than the human brain, depending on the used electronics. * attention spotlight + Humans can at maximum track 4 objects at once (see [attention](https://www.sciencedirect.com/science/article/pii/S0896627304002971)), which have to be evenly dived between 2 spaces. Meaning we got roughly 2 threads, a robot can have multiple threads, meaning it can spread it's awareness to more objects. ### Disadvantages * Wear + Electronics break down, means we need spare parts. Also if certain parts break down the robot will cease to function until it is repaired and will be unable to repair itself. ### Summary While the robot can repair itself on a mechanical level, it is rather difficult to repair it's own electronics. Since the electronics controll it's behaviour, it would require "redundant" (well not really redundant, we could use this as seperate threads) implementations (meaning if we remove board a it will still function but loose performance) and regular checks of all it's electronic parts. Or exchange parts before they expire. However this is quite a lot of work, and there still is a chance that a part breaks down before it expires so this is all kinda whacky. ## Fencing / Swordstyle One gotta get rid of the idea of fencing and thing of butchering if thinking of a "fencing" robot. Why is that? The largest factor in any fight is physics, an expert may overcome this partly due to experience and technique, but the stronger/faster guy wins. What will our robot do? Walk to the person, lift blade, strike at person. It's strikes will be not blockable by a human, because it is a magnitude stronger. Ignoring the isane speed possible, which would make it impossible for a human to react. So yeah it will just butcher people, no fighting, no fancy sword battle, just a robot walking up and butchering people. If it has not that behaviour it is due to the inabbility (highly doubtable if one is able to build something like this) of the constructor or due to his intention. So our robot could wipe the entire population, that is just dependant wether the humans can faster respread to wiped areas than the robot can reach not wiped areas. ## Countermeasures What our robot dislikes, except time, is a large impact. Meaning a boulder thrown by a catapult, dropped from a wall or a cannonball. While it could be possible to absorb most of the shock using a laminate structure and non-newton liquids, I highly doubt it can do so multiple times. There is a reason why armor vests break down when beeing shot at, and our robots armor will also wear down if it is shot multiple times (or once with a large enough thing). Electronics can also break down due to impact, a simple example is a phone breaking when dropped with no visual damage on the outside. A human fighter would try to face it using weaponary against armor, meaning a weapon providing a long leverage, a decent weight and impact on a point. In short a warhammer. That would at least be able to damage the, if it would be hit multiple times. Thing is you gotta walk through fast moving blades to hit the robot, so I'd go with siege weaponary. A scorpion should be quite efficient. Using nets and ropes would allow to entangle the robot and allow the attempt to bring it down, so it can be smashed with hammers. That's it for my little excursion into mechanical engineering, feel free to ask any questions. [Answer] Morale Humans fear death. Most humans also instinctively fear killing other humans. During the history of warfare large part of the tactics was designed to overcome this limitation, by drilling them into formations. And still, battles weren't won like in video games, by one side losing all soldiers fighting to the death. Losing 10%-15% of soldiers usually led to the army running away in panic. It often happened that an army routed which had actually better chances to win. In the heat of the battle you don't see very far. You only see what happens in your immediate vicinity. If the one standing by you panics, turns, and flees, you don't know the whole situation. You only know that you are now more vulnerable because your battle line has a gap right besides you. Then another one of your comrades turns and flees. If you stay you will be cut down. So you have to flee too. Even if the battle was nearly won, you don't know it. And that small panic might spread and make your whole army rout. Robots wouldn't have such problems. [Answer] A robotic swordsman wouldn't need anything too over-the-top to be incredibly powerful. They'd have a lot of much smaller things that would give them significant advantages. For example, one strategy used in one-on-one sword combat is to disarm your opponent. Even when your swordbot doesn't use permanently-attached weapons, it can still have mechanical interlocks (like double-jointed fingers that wrap around the hilt in both directions and lock together at the back) that prevent the sword from being dislodged. The robot can disarm a human, but not vice versa. Taking that thought in the other direction, your robot could fairly easily disarm a human. It would be able to block an incoming blow with its off hand, grab the opponent's sword by the blade, and twist it free from his hand. An extremely low-tech advantage that your robot could have is to buff the thing until it has a mirror-like finish all over. Fight your battles outdoors during the day. Your human opponent will constantly be blinded by the glare, but a simple optical filter makes your robot immune to it. Any fencer will tell you that balance and footwork is key to success. You can distribute your robot's mass in a non-human-like manner to make it better at balancing. Moving a lot of mass to its off hand could allow the robot to fight in a sideways stance like a fencer, using the off hand for counterbalance like a tail. If your robot uses a long, thin blade like a fencing foil, it would be able to strike with considerably better precision than even the best human fencer. The weapon is generally rigid and inflexible and acts like another segment of the robot's arm. The cognitive load for a robot to move from a two-segment arm to a three-segment arm is trivial. Human brains don't do that very well, as our computational power is generally limited by our biology. Your robot swordsman would have game-changing abilities as far as sensors go. It could see its opponents equally well at night and during the day. Infrared sensors could detect when an opponent is breathing heavy and fatigued. Zoom lenses could be used to find small imperfections in the opponents armor for targeted attacks. The amount of time it would take for your robot to detect an opponent's movement and react to it would be an order of magnitude less than for a human. This allows the robot to counter/block almost any attack. When an opponent counters/parries, the robot can react fast enough to adjust the angle of attack and evade the parry. When fighting with larger swords designed for chopping and slashing, dynamic armor would enable your robot to avoid most damage. The individual plates on his armor would have their own actuator that can tilt them in multiple directions. The robot can continually track incoming blows and re-orient the plates to ensure that each blow glances off and does a minimal amount of damage, as if it were covered in a hundred tiny [bucklers](https://en.wikipedia.org/wiki/Buckler). Even with static armor, it would be able to twist and re-orient its arms and body to achieve the same effect. The best part about small advantages like this are that they can be selectively activated by the robot. Just when the human opponent thinks they're winning, the robot laughs at him and [raises the difficulty level](http://www.moviequotedb.com/movies/princess-bride-the/quote_30414.html). [Answer] A robot can have a number of advantages over a human in a sword-fight, simply by virtue of its construction. Since the robot is specified to be humanoid, its advantages will be things that it can do better than a human, not things that a robot of a different shape could do to confuse an opponent. Firstly, humans are soft-skinned and easily damaged. When wielding edged weapons, wearing armour is highly advisable to avoid their skin being punctured or cut. Since a robot can be made from far stronger materials than human skin and flesh, it is unlikely to be damaged by a sword blow from a mere human. Secondly, Robots may be considerably stronger than an equivalent sized human (in terms of both mass and volume). They may also be heavier, with a mass greater than that of an equivalent human. Thirdly, a robot does not have a human's energy supply problems. Unless it runs out of energy entirely, its actuators are most likely to be designed to supply maximal output indefinitely, until its power supply runs out at least. Fourthly, a robot may be capable of much greater precision than humans. Our senses are all 'analog' in that we can't say with any great degree of precision where the parts of our body are or where other things are. A robot may be capable of far greater accuracy and precision Fifthly - and most important of all - a robot can be fast. If made properly, its reactions could easily outstrip those of a normal human... and this is the most critical point. As an instructor, a robot may limit its speed in order to simulate a real opponent, but it would always be able to be just that bit faster. Once the robot's decision-action loop drops below 200-250ms, the lower limit for human hand-eye co-ordination, there will be the feeling from human opponents that they are outmatched, that whatever they do, the robot can answer, and they are hard-pressed to respond. As a human fights this robot, it may opt to introduce artificial delays into it's decision-action loop in order to simulate an unskilled opponent. To a human, it will feel as if the robot cannot respond to the human's actions, and the human will score hits against it, though of course, being armoured, it will be pretty hard to damage. Then, as it ramps up its reaction speed, the human will have to work harder and harder to make a touch, and when it gets to around 250ms reaction time, its strength, accuracy and precision will make it a very challenging opponent, and few human swordsmen other than masters of their art could score a hit. However, as the robot continues to ramp up its speed, reducing its reaction time yet further, its human opponents will get the feeling that no matter what they do, it seems to know almost before they do it, and is already moving to counter. As its speed increases and its reaction time reduces yet further, it will seem that the robot is playing with them. No matter what they do, the robot not only anticipates, but does so with seemingly contemptuous ease, scoring hits against them even as they try to hit it, then going back to parry their own strikes. By the time the robot gets up to its top speed and down to it's real reaction time, on the order of 25 to 50 ms (which is currently achievable and has been demonstrated with real-world technology), it could score five or more hits while its human opponent is still trying to score their first hit. If the robot was not concerned with teaching, and simply wanted to eliminate its human opponents, it could simply walk into a massed group of human opponents, and cripple or kill them as it chose. It would hardly matter how many humans there were, unless the robot didn't have enough stored power to cut them all down. To the robot, the humans would be almost as slow as a snail trying to hit a human... or a hundred snails all trying to hit it. It wouldn't matter how many, since only a half-dozen humans at most could be close enough to reach the robot, and part of its observation-reaction loop would be prioritising its targeting and defensive actions. It would so greatly outclass its human opponents that it could choose not to kill them, to instead give them injuries that would leave them unable to continue fighting while they were futilely trying to hit the robot. [Answer] The Swordsman is an evolved weapon of combat, for use in scenarios where boarding, infiltration and assault are necessary, or where the use of projectile weapons could compromise a target (like a spaceship or aircraft). Delivered by cloaked breaching pod, a single ninja assassin can infiltrate a craft or base, eliminate command and override all systems-- this strategy was used most effectively in the Battle of 2770, when several UNN capital ships were subverted and scuttled right at the apex of battle. Because the role of the robot requires moving through spaces and manipulating interfaces designed for humans, ninja assassin robots are humanoid in nature. In fact, they are most effective when designed with chameleon skin to mimic the appearance of members of a crew or base garrison. The robots are armed with a sword -- as they are incredibly fast and strong, this is usually all they need for their task, but of course they are also equipped with projectiles, flashbangs, smoke bombs and other cool ninja assassin gear. ]
[Question] [ Closed. This question is [opinion-based](/help/closed-questions). It is not currently accepting answers. --- Want to improve this question? Update the question so it can be answered with facts and citations by [editing this post](/posts/140222/edit). Closed 4 years ago. [Improve this question](/posts/140222/edit) In popular culture on my Earth-like planet, alien-abduction stories, anal probing and conspiracy-theories are well-known but largely considered by mainstream culture to be delusions or fanciful ideas taken up by the imaginative, the lonely and the desperate. Tales often have the common feature describing sadistic experiments, transplants eavesdropping on our thoughts and anal probing. Of course it (mostly) turns out to be true. One fine day, an alien fleet turns up, takes over all the communication channels, disables the military-infrastructure of the world instantly by computer virus and demands that we surrender on pain of planetary destruction. After brief attempts at negotiation, threats, a few feeble attempts at shows of force, humanity complies. The aliens land in cities all over the world and demand that everyone submit to one specific test - an anal probe. When asked why, all they will answer is - "It is necessary for the survival of both our species." What reason could a technologically and militarily superior race have for wanting to probe everyone's anus? # Accepted answer: Whilst any brilliantly argued answer (with a valid frame-challenge) may be accepted, in an ideal world these conditions will hold: * The humans will not immediatley understand why what happened has happened, but as the aliens depart after the "event", they are left with a powerfull and lasting racial memory. * Humans, on moving out into the galaxy, encountering other races, forming alliances and becoming part of the larger galactic civilisation - stumble upon the answer to the riddle and choose to seek redress through the Galactic Courts. * The Galactic Courts have "Sapient Individual's Rights" roughly equivalent to The [Geneva conventions](https://en.wikipedia.org/wiki/Geneva_Conventions#Conventions). * The Aliens put-up no defence, the humans win outright and recieve substantial compensation. * The Aliens continue as before. As per JBH's comment, the implication is that comments should have been left asking how better to define the question before any answers were published. My fault for asking a badly constructed question, your fault for answering rather than commenting to improve the question. Your answer is technically still valid, and you may still edit it. None of this implies that an acceptable answer has not already been written, but I need to keep the question open the customary 24 hours before I award that. [Answer] *Please note that this answer was submitted before the question was edited to include the new 'Accepted Answer' conditions.* --- The aliens are a parasitic race > > The aliens land in cities all over the world and demand that everyone > submit to one specific test - an anal probe. When asked why, all they > will answer is - "It is necessary for the survival of both our > species." > > > It's a veiled threat The aliens are implying that if humans don't comply then they will wipe them out. What they really mean is that they desperately need humanity for their survival. The aliens Since a disastrous disease killed off the hosts of their parasitism. They have been desperately searching the Galaxy for a new victim species. The best they have come up with is humans but initially the eggs they implanted didn't survive. After years of research they have developed a bacterium that will live in human bowels and make the environment suitable for their eggs and offspring. When the larvae are ready to be 'born' they are about the size of a human stool and brownish in colour. They are excreted and swim off into the drainage system. Here they make their way to rivers and streams where they predate on other water creatures. Eventually they emerge from the water and take on their land-living form whereupon they seek out their kind and are integrated into the alien society. The test This is a lie. Now that the research has been done the aliens are ready to implant eggs. It's not a 'test' it is mass implantation into their new host species. The probes are actually ovipositors. The victims never see this because they are held face down during the procedure. [Answer] Because humans are really stupid and overestimate the importance of brain because, no surprise, it's their brain who tell them he's the important one. But there are only 100 millions neurons in brain. 5 time less than in guts. Aliens know that (that's why they are so advanced) and after doing "catch and release" they concluded they need to do mass check-up on humanity. They are aliens so they have aliens reason to check us. Some of them may include: * A gut bacteria that is actually interplanetary threat to any more developed race. Aliens spotted our tries to escape solar system and want to stop humans from making everyone in the galaxy dumb (like we think that brain eating bacteria make us dumber). * We are showing strange development in the gut region and it may make us go extinct. And for alien we are like white doves at Disneyland. * Aliens are much more advanced technologically. Their MRI scan is much better when done from inside and the easiest way is through rectum. [Answer] They want to understand how a bipedal species could achieve the level of intelligence we did. ![You other brothers can't deny](https://i.stack.imgur.com/87QlN.png) Source: <https://www.smbc-comics.com/comic/evolution-3> The aliens are born from cloacas, and they can't understand the difference between cavities and have mistaken human asses for human birth channels. [Answer] # It's a large scale health study Every few years there's another breakthrough in what your gut bacteria say about your health. These aliens have taken this down to a fine art apart from one particular aspect, how to gather and identify the owner of the bacteria in question. This particular aspect they're still doing the old fashioned way. Somebody once said that the only way to be absolutely sure where the bacteria came from was to take the sample directly, and it stuck. Now they, as a culture, have become too homogenised. They no longer have the range of diets and environments to maintain the variety of bacteria that humans have. Something is slowly killing them and they've traced it to a lack of certain bacteria in the gut. If they can't get what they need, the next generation may be the last. And as for why it affects human survival? They'll kill us all if we don't cooperate. Corpses don't fight back. [Answer] Religion. That's really the easiest answer. Why would someone do something illogical at great personal expense? Because of an illogical motivation like faith guided by religious rules. The most basic motivation of this kind is some supernatural punishment for not completing certain objectives like following a set of commandments for daily life. In this specific case the aliens belief refusal could perhaps trigger an armageddon like event. If you want an explanation of why they started with the occasional abduction call it research. They needed to ensure we qualify. Once the clergy was satisfied we did an invasion was launched. Now for as to what the aliens exactly belief, that's up to you. [Answer] There is another alien species that works in a "puppet master" fashion, it is ingested and grows from eggs before attaching itself to the gut lining like a tapeworm. It then sends filaments out into the body and gradually influences and then takes control of the host body. The new aliens are cleansing the galaxy of this threat and perform random sampling of all inhabited planets on a regular basis. The most recent sampling discovered an infected individual on earth. They now need to screen the entire population and contain the threat. [Answer] # Proof of innocence On their homeworld rumors that humans have eaten their young abound. If anyone had done this, it would have altered the microbial flora of their digestive system, and could easily be detected by an anal probe. While most aliens dismiss this as fake news, a powerful militant faction is calling for the destruction of all humans, and is gaining popular traction. Of course, if the aliens did commit genocide against the humans, the intergalactic community would come down on them hard. Alternatively if proof of humanities innocence can be shown the militant faction will lose face in the alien's social media networks. So that's where we are, in order to prove that humans haven't eaten any of the alien progeny, every human must submit to an anal probe to prove their collective innocence. [Answer] Humans have a better immune system than the aliens do. The Aliens have a viral disease that will, in time, kill them all. However, compared to the Aliens, humans have an awesome immune system. Primarily because we are a young and a new race, and not particularly bright, and have been living in [rivers of our own sewage](https://en.m.wikipedia.org/wiki/Great_Stink) for millennia. Out of survival necessity we have phenomenally powerful immune systems compared to the Aliens. So the Aliens decide to infect us with the virus, to see if we can kill it. So now the clock is ticking. Both races are doomed to die. But if one human's immune system is able to manufacture an antibody that can kill the virus, the Aliens with their superior tech could take that antibody and synthesize it into a cure. So immediately, all Humans must be probed! The Aliens have to hopefully find one human that is able to kill the virus, to save everyone. Please report to your local probing station at once. [Answer] I'm thinking there are a couple main threats that could potentially wipe out both species (and be solved by anal probes) 1. A disease spreading across the galaxy has devastated the alien species, and due to the genetic similarities between our two species, will likely do the same to us if we become exposed to it. 2. Some third race (potentially either some intergalactic locust or an incredibly aggressive military empire) has been going from world to world wiping out all life. The alien species identifies that they may be susceptible to earth born pathogens from the initial case study of anal probes, and devises a large scale study to cultivate the most deadly pathogens to these species and release them as bioweapons. In case 1, they may be looking at what bacteria and viruses our body already has defences against- alternatively they may be taking samples of human DNA to reproduce in the lab, and test the disease on. In case 2, the answer to their problems lies in the wide range of bacteria we have in our guts, viruses etc. Through this large scale study, they hope to get a large sample of microorganisms which they plan to breed and test on test subjects from race #3. [Answer] There is an interplanetary war in all the galaxy. The aliens have just found a planet with 7 bilions of potential space soldiers, but they must perform a preliminary screening to find the best suited individuals to wear their super-powered battle-mecha-suites and fight alongside their alliance against an evil race of brain-sucker insectoids. These suites can be controlled through a neural interface, and the alien scientists have discovered that the best place for the neural interconnection (in the humans) is the last trait of the intestine... So all humans must undergo an anal probe to individuate and enlist the best soldiers (the ones that can connect to the mecha-suites in the most functional way... Think of Pacific Rim). The defeat in such war would be a dysaster for all not-insectoid races in the galaxy, so the mass-probing is essential for the survival of both humans and aliens! [Answer] 1. They are slaves to a master race of sadist who demand sodomizing. The race doing the sodomizing is the master race's 'Silver Surfers' of prime booty holes. Those who have the butts, control the universe. 2. Different life forms absorb and process radiation differently. Species of a certain intelligence level or capability are tested for mineral, waste, and radiation concentrations in this area to determine long term longevity following random universal incidents (cosmic rays, background radiation, nuclear oopsies, etc.). 3. Similar to phrenology, buttology tells them the traits they can use to instantly judge us and destroy those that would cause the them/us or the entire universe harm. 4. Just kidding! ]
[Question] [ I'm trying to make a place that is a part of a nation but not under its government's rule, specifically a mental institution. It has dark secrets within its walls. I want to write a mystery story which contains lots of dark themes, and a detective needed to find out the mystery behind it without the help of the government. However, I'm not sure how I can keep the mental institution running if it's violating the laws of the government. [Answer] ## Exceptional Politics Related to sovereignty and treaties: * The United Nations. The [1947 treaty](https://treaties.un.org/doc/Publication/UNTS/Volume%2011/volume-11-I-147-English.pdf) for the New York headquarters states: > > “Federal, state or local officers or officials of the United States, whether administrative, judicial, military or police, shall not enter the headquarters district to perform any official duties therein except with the consent of and under conditions agreed to by the Secretary-General.” (Section 9). > > > * Embassies and consulates are regular buildings but are commonly excluded from the jurisdiction of the local government. * Gambling regulations can be circumvented by locating a casino on Native American reservations or on boats. * [Bir Tawil](https://www.amusingplanet.com/2018/02/bir-tawil-land-no-country-wants.html?m=1) is claimed by neither Egypt nor Sudan. * [Kowloon Walled City](https://en.m.wikipedia.org/wiki/Kowloon_Walled_City) in Hong Kong, known for being run by organized crime in practice, but the situation was created by relations between China and the UK. Related to administrative districts: * Special police jurisdictions exist for universities, railroads, fairgrounds, parks, etc. * An administrative error in defining boundaries. In 2015, the Business Loop 70 Community Improvement District tried to define its boundaries to include only commercial properties, but [mistakenly included a few voters](https://www.columbiamissourian.com/news/local/one-vote-spells-victory-for-business-loop-70-cid-sales-tax/article_95ff6570-9abd-11e5-b462-933cedae14c5.html). * Protest zones, shanty towns, communes, and similar loosely organized areas, the inhabitants of which may prefer self-government and be hostile to outsiders. Unusual cities: * [Rolling Hills, California](https://en.m.wikipedia.org/wiki/Rolling_Hills,_California). It’s legally a city but is 100% residential and is gated to exclude non-residents. * [Vernon, California](https://en.m.wikipedia.org/wiki/Vernon,_California). The city government is focused on its almost exclusive industrial land use, with 100,000 jobs. There’s less than 200 residents, and most live in City-owned housing, so it was feasible to rig elections. [Tenants were screened for political opinions and evicted if they supported political opponents](https://www.uscannenbergmedia.com/2016/03/30/vernon-a-city-of-change-or-a-city-of-shame/). Anomalies: * [Inholding](https://en.m.wikipedia.org/wiki/Inholding). Privately owned long before the government decided to designate the area as e.g. a National Park. * The [Berkeley Free Speech Monument](https://99percentinvisible.org/episode/episode-22-the-invisible-monument-to-free-speech/) is a small patch of dirt surrounded by the inscription: > > “This soil and the air space extending above it shall not be a part of any nation and shall not be subject to any entity’s jurisdiction.” > > > [Answer] Just make it a religious institute. There are plenty of examples in real life that "what happens in a religious institute stays in the religious institute", not even mentioning that in the past churches were granted the privilege of being extra territorial places. [Answer] Exclave [![Kaliningrad oblast](https://i.stack.imgur.com/FJtuK.png)](https://i.stack.imgur.com/FJtuK.png) An exclave is a spot which is officially a part of a country with which it is not contiguous. [Kaliningrad](https://en.wikipedia.org/wiki/Kaliningrad_Oblast) is an example that has been in the news lately. It is a little piece of Russia surrounded by Poland and Lithuania. Life there depends on the relationship between those countries and Russia. Your mental hospital is in an exclave. For historical reasons it is part of a different, powerful but fairly distant country. The borders of the exclave are formally international borders though perhaps more is made of this for some than for others. I envision your exclave as even smaller than Kaliningrad. They are governed by their own laws and by those of the distant parent country. The national law enforcement of that parent country does not often come to the exclave to make sure things are in order. [Answer] A functioning state means there is a government to exercise sovereignty over the territory. There area legal system and police who claim a [monopoly on legitimate violence](https://en.wikipedia.org/wiki/Monopoly_on_violence). The flip side of this monopoly is that they must exercise it on behalf of citizens who have been wronged. But a democracy also respects the rights of their citizens, including privacy. The only time I've seen on-duty police in my home was when I reported a bicycle theft from my back yard. They don't drop in for random checks where I live ... This principle can become turning a blind eye, as when the Catholic Church got away with [investigating and obfuscsating](https://en.wikipedia.org/wiki/Catholic_Church_sexual_abuse_cases) sexual abuse by themselves. Or when various churches decided to offer [sanctuary to refugees](https://en.wikipedia.org/wiki/Sanctuary#Sanctuary_in_contemporary_society) who were to be deported. What these cases have in common is that the government refrained from enforcing laws for fear of public backlash. The church has a good reputation with people who normally back the state institutions, and so the government agencies simply find other crimes to investigate before they open that file. A different mechanism applies when there are people who normally hate the state institutions, and if the government agencies decide to pick their fights carefully. Some time ago, in Berlin, [squatters were evicted](https://en.wikipedia.org/wiki/Liebig_34) from an occupied building. The police deployed roughly 30 officers per squatter, because they expected violent protests by part of the community. This action was planned and authorized by senior police and political leaders with a significant lead time, while a normal eviction involves one bailiff, perhaps one patrol car, and possibly a few hired movers. A critic might say that the squatters got away with defying court orders far longer than an ordinary eviction case, because of government fear. Your mental institution would probably use the first option. * Assume strong protections for patient confidentiality, with fearsome lawyers to back it up. * Assume that powerful people were able to have inconvenient relatives declared insane and admitted, either to keep them out of a jail or to keep them from exposing a scandal. Now the doctors have phone numbers on quick-dial. * Assume that the general public is familiar with people making "wild" claims every decade or so, and the "whistleblowers" being declared insane by the medical expert witnesses and the legal system. [Answer] I would suggest a very remote location. Perhaps somewhere in a very high mountainous area with a very high pass on the border between two countries that used to be of strategic importance. Perhaps a large fortress was built there and extended and enlarged over the years. Then eventually a better route was found through the mountains - a tunnel perhaps or maybe tensions eased between the two countries border or a huge landslide made access to the fortress very difficult or allowed a different route further away. The fortress fell into disuse for sometime but eventually was taken over by monks and then in the fullness of time became a mental institution. The remoteness makes control and oversight difficult from central government so the institution is left alone. It is also in a semi-autonomous / demilitarized border region making it even less easy for government oversight. Technically any oversight is via a commission set up for the semi-autonomous border region, but that has been under funded and only really exists on paper. So there is no effective oversight and nobody lives anywhere near it. It has a front that shows it's an austere but well run institution. Government is lax and only too happy to keep the status quo and also get rid of some very troublesome mental patients. The few comments or complaints that do arise are directed to the semi-autonomous border regions joint administrators (for all the good that will do anyone). [Answer] This has happened before. The first example that springs to mind is Kowloon Walled City (demolished in 1994). <https://en.wikipedia.org/wiki/Kowloon_Walled_City> Hong Kong simply left it to run itself as it would have been very costly in both lives and money to properly control. [Answer] There are quite a few examples of real-world autonomies to a different degree, sometimes for quite a while (e.g. centuries): * Universities * Temples * Monasteries * Ghettos * Crime gangs * combinations thereof (all of these can go together) The stability criteria is some combination of: * Means of existence (e.g. a steady stream of trade, goods, services, etc) * Strong support from the locals, another government or some other strong enough factor * Not being enough pain for the local government so it doesn't try to fix the situation [Answer] It's in an area claimed by no state, like [Bir Tawil](https://en.wikipedia.org/wiki/Bir_Tawil). Bir Tawil is an area that is, due to funky border disputes, claimed by neither Egypt nor Sudan (in fact, they each claim the other country owns it). Real life is sometimes weirder than fiction. There aren't many other real life examples of this, but a few exist, see [terra nullius](https://en.wikipedia.org/wiki/Terra_nullius). [Answer] There's still a few unclaimed areas in the world. In particular, there is an area called Liberland / Gornja Siga between Serbia and Croatia that both countries disavow owning. They both want to claim a bigger piece next to it and there is some history meaning that one nation has to get one piece and the other nation gets the other; they both claim the big piece and reject the small one, which is Liberland. In practice, no one can get in and out because the Croatian military keeps it ringed with troops, but it wouldn't be hard for an author to imagine Croatia allowing an asylum there and then pretending it doesn't exist. There are a few other debated terra nullius's around but mostly in the third world, and I assume your setting is in a developed country. [Answer] Apartheid There exists a race or class of people who are legally considered lower-class citizens in this country. The institution was built, and the doctors hired some time ago by a well-meaning wealthy philanthropist, in order to treat the mental health of people from this group. However, over time the philanthropist either lost interest, died, found out it was more difficult than they anticipated and lost control of the place. The place is now run entirely by people from this lower class, and due to government neglect, the area in which it was built has fallen to ruin. But it's the only hospital that will treat these people. Them not being considered full legal citizens of the country, the government feels no obligation (or indeed might have convinced themselves they don't even have the right) to get involved in the running of the place. But the people who are supposed to be in charge - because they have not been allowed to have a proper education - can do little more than make sure the place stays in service, or are perhaps corrupt themselves. ]
[Question] [ I'm new to asking questions so please forgive me if i'm strange. I have a species of plant-based dragons. Small, covered in feathers and intelligent. I just want one thing backed up for me because I haven't been able to find anything to back me up: Can a wing and an arm merge together? Dragons are naturally six-limbed, but the species I'm talking about has the skin and muscles of the arms merged into the wing. They walk on their knuckles, leaving the wings folded up. Is this feature able to be sensibly evolved? Edit: I realize I could've done better with explaining so I pulled out this old image. [![enter image description here](https://i.stack.imgur.com/nzrIw.jpg)](https://i.stack.imgur.com/nzrIw.jpg) Originally two separate limbs, bonded together by skin and muscle, but not bone. [Answer] It's a bit of a "just so story" but here goes. The big deal is, suppose the dragons liked to nest in cliff faces. That would mean it needed to be able to do rather serious maneuvers. The colloquial term is "catching an egg on a plate." It would fly directly at the cliff, a little low, then at the last moment swoop upwards and put on the brakes, perching on the edge of its doorway. Some birds can do this, such as the barn swallow. It nests in places like the edge of beams. [![enter image description here](https://i.stack.imgur.com/SaoBe.jpg)](https://i.stack.imgur.com/SaoBe.jpg) This is a flying squirrel. He does not really fly but mostly glides, with some significant ability to "duck and turn." He's doing this to go from tree to tree without having to touch the ground, thus decreasing his exposure to predators. By the way, notice how thin and "birdlike" his limbs are. [![enter image description here](https://i.stack.imgur.com/DONVE.jpg)](https://i.stack.imgur.com/DONVE.jpg) Imagine your dragon started with four legs and wings. Then it added some skin folds, or possibly secondary feathers on the fore-limbs, that it could extend for control on landing. That gives you a pattern with both wings and skin folds. Birds have tails that they use very effectively for control. Maybe the dragon's wings were good for ordinary flight but not quite the best for detailed control, and sudden changes in direction, that landing on a cliff face might require. Nesting in a cliff face has fairly obvious advantages. It's hard for most potential enemies to even know there is a dragon nest there. Getting to it would require either similar ability to fly, or outrageous ability to climb. Maybe the dragon does some remodeling of the cliff face specifically to make that more difficult. Possibly making it over-hung and very smooth. Then the dragon's eggs are in a fairly safe spot while the dragon is out hunting its preferred food. So the dragon might start out with folds of skin, or even secondary feathers on the fore-limbs. The current dragon might well show some "vestigial" remnants of this evolutionary path, maybe with some skin folds that it "fluffs out" when it's doing particularly difficult flying moves. Or perhaps they have been re-purposed for signalling such as in the mating season. [Answer] Gobies fused their hind fins. <https://en.wikipedia.org/wiki/Fish_fin> > > The paired pelvic or ventral fins are typically located ventrally > below and behind the pectoral fins... They are homologous to the > hindlimbs of tetrapods. The pelvic fin assists the fish in going up or > down through the water, turning sharply, and stopping quickly. In > gobies, the pelvic fins are often fused into a single sucker disk. > This can be used to attach to objects... > > > [![goby with fused pelvic fins](https://i.stack.imgur.com/rrt89.jpg)](https://i.stack.imgur.com/rrt89.jpg) <https://en.wikipedia.org/wiki/Pelvic_fin> Fish have more limbs (fins) to work with and have had more evolutionary time to work so in fish you can see more of the phenotypic evolutionary variation possible for chordates. If fish can fuse functional fins into organs with a completely different purpose, that should be possible for your hexapod dragons. [Answer] Dragons are not a real thing. So there is no general rule that they have to have 4 legs + 2 wings. Regarding the evolutionary aspect of the question: Birds have done pretty much that. They "gave up" 2 legs in order to evolve wings. As evolution works extremely slow, there probably was a time when the predecessors of birds limbs that were kind of like legs and wings at the same time. Or you can look at bats. They have claws on their wings and they walk pretty much the way you described it. Edit: Regarding the question if 2 limbs can merge. If it is possible, then I guess it is extremely rare. For a mutation to spread it must provide an advantage. If you start with 4 legs + 2 wings then having 2 legs + 2 wings is no advantage at all. It means flying just as before but walking much slower. Also, even if there was some advantage that I just can't think of, then it would not be a merging of wings and legs. If the front legs were not needed anymore and therefore only dead weight, then they would gradually become smaller until they pretty much disappeared. Then for whatever change in the environment, having some frontlegs would have to be important again, so those individuals who can somehow manage to use their wings for that would have the advantage and therefore propagate more. These wings would then -over many generations and only if the ability to walk like this stays important for survival- reshape into something that makes it easier to walk with. Being able to fly would also have to be important all that time, as otherwise the wings left after some generations might not enable flying anymore. Anyways, that would not be a merging, but a evolution to lose the frontlegs first, followed by another one to reshape the wings. [Answer] You should have a look at how the wings of butterflies and moths work :) [From Wikipedia](https://en.wikipedia.org/wiki/Wing_coupling): > > Some four-winged insect orders, such as the Lepidoptera, have developed a wide variety of morphological wing coupling mechanisms in the imago which render these taxa as "functionally dipterous" (effectively two-winged) for efficient insect flight. All, but the most basal forms, exhibit this wing coupling. > > > The more primitive groups of moth have an enlarged lobe-like area near the basal posterior margin, i.e. at the base of the forewing, called jugum, that folds under the hindwing in flight. > > > Other groups of moth have a frenulum on the hindwing that hooks under a retinaculum on the forewing. The retinaculum is a hook or tuft on the underside of the forewing of some moths. Along with the frenulum, a spine at the base of the forward or costal edge of the hindwing, it forms a coupling mechanism for the front and rear wings of the moth. > > > The frenulum mechanism mentioned above looks like velcro when you look at it. There are drawings in the wiki. > > In the butterflies and in the Bombycoidea there is no arrangement of frenulum and retinaculum to couple the wings. Instead, an enlarged humeral area of the hindwing is broadly overlapped by the forewing. Despite the absence of a specific mechanical connection, the wings overlap and operate in phase. The power stroke of the forewing pushes down the hindwing in unison. This type of coupling is a variation of frenate type but where the frenulum and retinaculum are completely lost. > > > Replace the fore wing with an arm or a paw and you get what you wanted, specially if you go for a frenulum. Velcro is strong enough to stick an adult man to a ceiling by the soles of the feet if you use the best quality fabrics, and it has the advantage that if your creature ever gets the limbs disconnected, they may reconnect again. The merge might be permanent (requiring medical help to reconnect right) or temporary (so the creature may remerge at will). [Answer] Have you looked at bats before? Their wings have actual wrists and thumbs. If you can justify the merger to make them walk on two wings and 2 legs by making them functioning claws allowing the creature to walk on 4 legs while only having 2. Like this poor little creature : <https://www.youtube.com/watch?v=OZC-qYDNVvc> With this "advantage" front legs become obsolete and removing them would be evolutionary beneficial due to the reduction of weight. [Answer] In the Disney Series "Gargoyles" the character of Lexington had a structure where his six limbs (two wings, two arms, two legs) had a membrane that connected his arms, wings, and legs together and was similar to a bat or flying squirrel when compared to his "human with wings" counterpart. This layout was distinct, but the larger gargoyle species had plenty of examples if you look at background characters. In Avatar (the blue people, not the airbender) all vertibrate life on Pandora have Six Limbs, though the Navi'i's are vestigial. There is a briefly seen "monkey" that has it's fore limbs split at the elbow rather than the shoulder, which is supposed to be an evolutionary forebear of the Navi'i and show the gradual loss of the third pair of limbs. In teal life, several species such as snakes and whales retain bone structure for vestigial limbs they no longer use and never develop (all four of the snake's limbs and the whale's two hind limbs) so it could be your "four Limb" dragon does have a bone structure that shows that they have not fully shed the now unused third pair. [Answer] Yes they can, and it's very likely that it would happen. As I've noted in questions about angelics, the muscles of the arms and wings are likely going to be shared. Assuming the European dragon the torso isn't elongated enough to have seperate pectorals for the arms and the wings. So to fly the muscles of the wings would pull on the arms and the pectoral muscles would pull on the other end, causing the end result to be that both arms and wings move downwards with the full strength of the Pectorals which is needed to fly. Since this motion is simultaneous and there is a lot of evolutionary pressure to simplify this by reducing the amount of muscles and mobility of the arms in favor of a more stable and stronger pectoral muscle movement it is likely the arms will eventually merge with the wings. [Answer] First of all, I totally love your drawing. It's actually completely feasible to have a species that has wings and arms merged. There are definitely a few things to consider, though. When you say that their wings and arms are merged, I'm assuming you're implying that the arms are functional and can be used like normal limbs. Pretty much any animal with wings does technically have a limb with the wing part attached to it, but the arm isn't very functional. This is because it needs to stay thin, aerodynamic, lightweight, and isn't used as an arm. Having a functional arm would make flight extremely difficult. So, consider these details about the species: * The arm is a fair bit weaker as a sacrifice for weight * The body is smaller and/or the wing and arm are much longer and bigger so as to account for the size of the body * Flight cannot be sustained for large amounts of time Now, onto another detail you asked about. Having the species walk around on their knuckles is also feasible, although, and this is just my opinion, this would be a bit more awkward and different than what's normal. Their bodies would be closer to that of an animal in terms of limb function, and thus may even have paws, and thus, it would completely negate the fact that they have wings. So, instead, consider this: The species walks on two legs, but because they live in difficult terrain with jagged and jarred, varying heights, and as a result, their fists are born calloused and able to withstand having all of the species' body weight on it for extended periods of time in order to navigate the terrain. From an evolution standpoint, having the environment of their old home as a height-differing terrain, a tall forest would make sense, can explain the need for wings. Say their food grows super high on trees, so their wings evolved in order to reach the food and to hunt more effectively like birds do. Awesome idea! [Answer] Maybe not quite what you were looking for, but there are a number of animals whose limbs have over time shrunk to the point of uselessness and become merged into their bodies. The ancestors of whales and dolphins had hind legs that disappeared over time. There are still remnants of them that can be seen in the skeletons of modern animals. Likewise, snakes lost all of their limbs over time, but these too can be seen in their skeletons as vestigial bone structures. And there are even a few cases of snakes found with actual visible (though non-functional) legs. Ostriches and emus have visible arms/wings, though they have basically no muscles in them and cannot use them for anything. Give it another few eons or so, and their descendants may have no visible external arm structures at all, similar to the legs of whales or snakes. Or they might go the other way and evolve some musculature if it proves advantageous for some purpose. Even humans have vestigial tails, which in most of us have no visible external structure, but occasionally manifests on some people due to mutations. ]
[Question] [ Could a creature plausibly exist with its diet consisting of consuming ice, possibly for hydration? I'm unaware if it needs a secondary diet for nutrition, but how would its metabolism feasibly work? [Answer] As L.Dutch stated in his answer, no creature can live on ice alone. There simply is zero nutritional value in it, and a significant energy sink for melting it. But this does not mean you can't have a creature consume ice for other purposes. Here are two: ## Hide from heat sensing animals This creature could be a predator, trying to hunt creatures that can see body heat (infrared). Or the reverse, a prey animal trying to hide from predators. Either way, if it needs to quickly make itself match the surrounding temperature, this is one way to do it. ## Rapid heat dissipation The creature has an unstable metabolism, or is prone to extreme feats of strength that put a huge strain on its body. Either way, it is regularly subject to bouts of feverish overheating, and (considering its environment) one of the easiest ways to cool itself off is to deliberately consume a large quantity of ice. This takes advantage of the fact that melting ice [absorbs a huge amount of heat](https://www.britannica.com/science/latent-heat). [Answer] Ice is just water. Water helps with staying hydrated, but carries no nutrients. Dirty ice sometimes can be contaminated by algae and other things. They could supply some nutrients, but being a small percentage of the ice, the underlying ice needs to be eaten in large amounts. And here comes the second problem: ice is cold, and melting it takes away quite some energy, that has to come from the eater's body. Considering that in the Arctic having a decent protection from cold is vital, eating ice and throwing away that hard-won energy doesn't seem like a smart evolutionary move. Mind that eating ice is not comparable to diving into the sea, like polar bears, seals and penguins do: in their case they have a good insulation to limit heat dissipation. Swallowing and melting ice in the bowel cannot benefit from it. [Answer] TL;DR: no. Unless you were some kind of plant. Possibly a weird alien plant with acid for sap. --- Even if you could get energy from water (spoiler alert: you're not going to) you'd still need to consume other things, because you can't make any kind of structural compounds from hydrogen and oxygen alone, unless you're actually made of ice, Do you want ice golems? because that's how you get ice golems. Good luck working out a way to power them. Anyway, you'll need some sort of carbon supply. Happily on earth, you can get carbon from the air, and combined with energy from the sun you can combine it with water to make useful things. Getting energy from the sun, water from the ground and carbon from the air makes you a plant, rather than a "creature" as such. You'll also still need a source of all those other trace elements required to make photosynthesis work. Finally you'll have all sorts of problems, as a water-based lifeform, consuming ice. Your temperature will drop, your metabolism will slow or malfunction, and finally you'll freeze unless you've got a good source of energy from elsewhere to keep warm. That's why hardly anything eats snow or ice (though some things can live in it, such as [ice worms](https://en.wikipedia.org/wiki/Mesenchytraeus_solifugus) or [ice algae](https://en.wikipedia.org/wiki/Ice_algae) and they do well enough). If you wanted something weird and exotic, you could consider a [non-water based biochemistry](https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Non-water_solvents), using a solvent with a lower freezing point than water. The only kind that seems likely to work well in an earth-like temperature range is [hydrogen fluoride](https://en.wikipedia.org/wiki/Hydrogen_fluoride), which requires access to a decent source of fluorine-bearing compounds (tricky) and makes you dangerously corrosive to conventional terrestrial life. [Ammonia](https://en.wikipedia.org/wiki/Ammonia) might also work, though you'd boil above −33°C and I don't think you can get enough sunlight to do useful things with and maintain a body temperature that low. In either case, you could "eat" ice, use a photosynthetic process to produce useful energy storage compounds from water and air, and use them in dark and gloomy periods to keep your metabolism going. [Answer] The Black Surface Stingray from Auriga IV is what you are looking for. Auriga IV is one of those ice planets. Along the equator it has a thin 200 km wide biome with some weird creatures in it. The climate is pretty stable since the planet does not wobble when it spins, and because other factors you can ask climate scientists about. Temperature is between -5 and 0 celsius, most of the time. Snows some, but its not extreme. One of those creatures is the The Black Stingray, a huge, flat, hairy, 15 meters wide thing that filter feeds on the surface snow with a mouth that is almost as big as the whole body. It moves by pedal locomotary waves, rippling the underside of the body, so slow its boring to watch. But what is cool about the stingray? Its the hottest creature on the planet! Its skin its made of natural Vantablack(the blackest black substance known), absorbing up to 99.96% of visible light. The vantablack and the big surface makes this warm blooded creature possible. The Stingray huge "wings" exist for capturing energy from the sun and storing fat. The body of the creature is a 1 meter long, 50 cm tall between the wings. The wings cand fold slowly around the body to preserve heat during the rare ocasions when the temperature goes down beyond -5 celsius. Also happens during the hibernation period. Nutrition comes with the help of other creatures. Most Aurigan creatures live underground, in the soil that is just below the almost always thin layer of snow (43 cm in average). A lot of them are algae growers. They grow this green stuff on the ice, then collect it, dry it and keep it in their holes. But the Stingray is not a fussy eater. While it ingests mainly culture algae, it also goes for the less nutritious wild algae, cadavers, poop, anything, realy. I don't know how long this species will survive. This much rare and expensive hairy hide, moving so slow... It is however the blackest black in existence. My wife loves her Black Stingray Coat :D [Answer] Nuclear powered creatures and osmotic balance in hypersaline waters. The creature actually has a nuclear metabolism using some kind of subcritical isotope concentration, you will need to handwave this part, or ask it as a different question. Your creature uses the ice to dissipate heat, it swallows chunks of calving glacier for trace minerals including the isotopes it needs, but it is also using the ice to dissipate heat, the fresh water it generates is more important, especially as polar oceans are often hyper saline. It prefers ice to sea water for cooling as it has to get rid of all the salt it takes in from the sea water, swallowing chunks of ice has far less salt. This does work better if said creature breaths air but it will work with gills as a sort of compensation mechanism, using fresh water to flush salts. And just becasue it is too perfect I need to share this image. [the iceberg devourer.](https://www.google.com/imgres?imgurl=http%3A%2F%2Fi.imgur.com%2FCUiYL.jpg&imgrefurl=https%3A%2F%2Fwww.reddit.com%2Fr%2FCryptidzoo%2Fcomments%2Fghkaw%2Fkretorius_iceberg_eater%2F&docid=Cf151m77flphiM&tbnid=X1cplscwgMEwMM%3A&vet=10ahUKEwj9keiyjfbjAhWSdd8KHQiHA5MQMwiiASgAMAA..i&w=800&h=687&itg=1&bih=697&biw=1288&q=iceberg%20eater&ved=0ahUKEwj9keiyjfbjAhWSdd8KHQiHA5MQMwiiASgAMAA&iact=mrc&uact=8) [Answer] I'm going to disagree with the above answers and suggest that it might be possible. It'd be a fairly unusual metabolism, but you could conceivably have a marine creature live in the Arctic eating mainly ice. Around the edges of Greenland's ice sheet, for example, the habitat contains both solid fresh water (ice) and liquid salt water. If your creature "eats" ice and "breathes" saltwater, it can obtain energy from the collapse of the concentration gradient as they mix in its body. This creature takes an ice meal, maybe from the bottom of an iceberg, and seals its stomach tightly. Separating its stomach from its lung is a thin impermeable membrane, covered in specialised ion channels and well-supplied with blood. These channels allow Na+ and Cl- ions to pass from the lung into the stomach, but not freely: they are constructed in such a way as to decompose water into hydrogen and oxygen gases, which are carried to the rest of the body by the creature's blood. With hydrogen and oxygen in the bloodstream, the creature's cells absorb these two reactive gases as needed, returning water to the blood as a byproduct of exertion. (You can imagine the ion channels as tiny paddlewheels driving electrical generators used to electrolyse water, and the creature's cells as engines burning hydrogen and oxygen to produce work.) As the ions enter the stomach, they cause the ice to melt via freezing point depresssion and build up, reducing the concentration gradient and slowing the metabolism. Eventually the creature must excrete saltwater from its stomach and take another ice meal. This is a pretty radical difference from most existing creatures, so it probably diverged a long time ago in evolutionary history - its most recent ancestor in common with humans might be a jellyfish! Conveniently, jellyfish are ectothermic and [some](https://en.wikipedia.org/wiki/Lion's_mane_jellyfish) live and metabolise in Arctic water, so your creature needn't be warm-blooded and spend the energy cost to heat the ice to its own body temperature. Now for the bad news: possible is not equal to practical. You can't construct much of a body just of the elements discussed so far (hydrogen, oxygen, sodium, chlorine). Remember that membrane it has with the fancy ion channels? That's going to need some carbon and nitrogen at a minimum, so your creature has to have a means to acquire these. So we have a conundrum - why wouldn't an animal just metabolise the carbon, if it can get enough of it to build itself a body? The cellular machinery for metabolising carbon is well-established, and unless the creature takes it up - and thus grows - very slowly, its carbon diet is almost certainly a richer source of energy than its ice diet. For the same reason, a salinity-gradient metabolism is probably limited to powering something resembling an ice-eating leech, and not a quick-witted or quick-moving one (muscles and brains both consume quite a bit of energy). Another consideration is that, if you can get the raw materials into the creature's body, it's probably worthwhile to design a better means of transporting energy to the cells. Hydrogen gas is not very soluble in water, so the body is going to have a hard time getting enough to burn. You probably need special blood cells to carry hydrogen, as our blood cells carry oxygen, or a system based on a different reaction altogether whose reagents and products are more soluble. Ultimately here are some obstacles this design would face, but if you want a slow-growing sedentary marine slug to colonise Arctic shorelines and icebergs, you might just get away with it! [Answer] This ectothermic creature filter feeds from the ice for the algae and organic material it contains. Imagine something that is (1) black, so it absorbs energy from the sun in order to melt the ice and pull out the organic food material from it. Or (2) have a body temperature below that of the melting point of ice, and instead of melting, physically crushes the ice it ingests and sift out the food particles embedded within. Maybe it physically separates the crystal grains to lick out the algae trapped between them with cilia or something It could exist for two reasons: (1) the seawater may contain predators that will see it as an easy meal, so it is forced to occupy the niche on or in the ice instead. Or (2)the sea ice have underwent some form of eutrophication, and as a result, algae that lives in ice and photosynthesize using the abundant refracted sunlight is very abundant within the ice. Maybe your creature will scrape off only the dirty top layer that had the algae accumulated in it. Or (3)the creature gets its caloric intake from somewhere other than ice, and only uses ice as a source of fresh water. This is especially true for certain mammals that is not fully adapted to living in salt water, so they require additional water that have to be both fresh and is not available in high enough amounts in its food supply. (Think Eskimos, who burns animal fat to melt ice for fresh water) an animal may do the same. it eats a very fatty, water deficient fish, and uses some of the calories from the fat to melt sea ice to get fresh water, as desalinating sea water will cost far more energy than melting ice.) [Answer] Engineer here. Dehumidifiers are portable air conditioners that pump the hot air and the cold air out together. The input is wet, room-temperature air. There is an air-conditioning coil (essentially) that cools the air below its dew point. When this happens, some of the water in the air condenses into liquid water. That water is trapped in a drain. The resulting cold air, with less water, is heated by the hot end of the air-conditioner, back up to approximately room temperature. Your ice-eating organism could work similarly in that the energy used to melt the ice could be recovered by re-freezing the water. Something something anti-freeze blood, but it would essentially "poop" snow or something similar. But, like others have mentioned, there needs to be something in the ice for the thing to eat. There's no point in shuffling water around. [Answer] Nutrition would be a main key factor because the creature would need energy to melt the ice into water to absorb it. So they would need to have some sort of energy intake before the ice. And that's why polar animals (bears or penguins) don't drink water/eat snow. when you need to eat first why not take the water with that caloric intake? [Answer] The problem is energy. Ice is, unsurprisingly, quite cold. In order to get hydration value out of it, you need to pump in enough heat to melt the stuff (a fair chunk) which still leaves it at the same temperature, and then enough heat to warm it up to whatever your body temperature is. That body temperature needs to be adequate for whatever metabolic processes you have going on. Starting int he arctic, where heat is not readily available, that's a lot of heat it's costing you, and a pretty heavy associated energy load... in a land not known for plentiful available food. "could plausibly exist" is a pretty large net. If one did exist, though, it wouldn't be running on standard metabolic paths. The cost of water gain by this technique would be too high. Any animal that depended on ice melting for water gain would be massively outcompeted by other animals that managed it more efficiently. [Answer] It would be easier to drink saltwater and filter it then warm up the mass amounts of ice to get enough water to survive (I'm assuming warm-blooded as it's in the arctic, but maybe it has "antifreeze" in its blood and are cold-blooded). The only reason it would do it is if there were "plankton" in the snow and it is a filter-feeder. ]
[Question] [ This question already has answers here: [Would a full body diamond armor and sword guarantee survival and victory against a medieval battalion?](/questions/54324/would-a-full-body-diamond-armor-and-sword-guarantee-survival-and-victory-against) (26 answers) Closed 4 years ago. I have been browsing the internet, and I have started to wonder whether a diamond sword is feasible or not. I would very much like to know the answer. [Answer] You could, but it probably wouldn't be worth the effort. Yes, diamond is hard, but unless you have an ABSOLUTELY PERFECT crystalline structure all the way down to the nanometer scale, any flaw, even a tiny scratch, would eventually turn into a massive crack as soon as you started applying impact force. You could put a fantastic edge on a diamond sword, but as soon as you started hitting things with it, it'd crack and shatter pretty quickly. Steel makes good swords because it's hard enough to take an edge, but soft enough to absorb impact without shattering. A major part of swordmaking is striking the proper balance between the two. [Answer] How about a cheaper route? The Macuahuitl, the "Aztec Sword" was pretty much a Cricket bat, but with obsidian blades inserted into the edges. If a blade cracked or was broken beyond resuse, you could just replace it. Following that idea, you could have a wooden (or metallic) handle and middle-part of the blade, and then have a diamond edge. While this is not a pure diamond sword, you do not need to worry about micro-fractures nearly as much, and repairing this weapon is a viable option, compared to a single diamond being the sword. [Answer] In practical terms, the other answers cover the macro scale - either a brittle blade of pure diamond (maybe used only for ceremonial purposes or special executions). Or a diamond coated blade. On a much smaller scale, diamond blades are used in laboratories, not as grit for grinding purposes - but as single atom thick (ideally, but in practice a few atoms thick at the edge) blades for slicing samples real thin - or as a [diamond knife](https://en.wikipedia.org/wiki/Diamond_knife) in a surgical procedure called [radial keratomy](https://en.wikipedia.org/wiki/Radial_keratotomy) (since the 1950's). The bad-news, 6 mm wide blades (0.236 inches) start at over $2,000 each (beware - [commercial link](https://www.tedpella.com/diamond_html/diamondk.htm#anchor1419008)). As swords go, this is even smaller than "handy pocket-sized". [Answer] Diamonds, mostly industrial quality and not gem quality, are used for cutting. As I remember, there are diamond edged saws for various industrial uses, and the diamonds on the edges have to be replaced as they wear out. So I can picture someone using a technological or magical sword with a chainsaw action and many tiny diamonds on the edges to improve cutting through armor or flesh or whatever. Maybe it cuts through anything and everything at the start of the battle but as it cuts through more and more armor and bodies the diamonds crack and shatter and the edge is reduced to mere steel and it only cuts as well as an ordinary chainsaw would. [Answer] Short Answer. No Most of the detail on why this will not work is covered in [this question](https://worldbuilding.stackexchange.com/q/25589/13516). While it may be possible to create a sword shaped object from diamond it is simply too brittle to be used effectively. On a side note a sword of pure carbon would also lack the mass to be effective against a similar sized steel blade. In swordplay inertia is often your friend. The subject of alternative materials has also been covered in [this question](https://worldbuilding.stackexchange.com/q/84592/13516) ]
[Question] [ We, the house of Habsburg, are a royal family that descend from the gods. Our founder, Cersei Habsburg, conquered Europe and brought peace and stability to the dregs of the continent. After taking her 3 brothers as husbands she founded the Habsburg dynasty. Our demigod status awards us the power of pyrokinesis and allows us an average lifespan of 500 yrs. Other demigod families throughout the world demean themselves by frolicking with worthless commoners, inevitably diluting their demigod heritage and weakening their gifts. These unions produce half-breeds weakling creatures of inferior quality in comparison to the purebloods. We however have maintained our respectability be keeping it all in the family. The closer the blood relation, the closer that offspring is in association with its fore-bearers. The Habsburg family are not ignorant of the dangers of inbreeding. However, we wish to keep our dignity intact instead of associating with lesser humans and allowing their genetic filth to taint our bloodline. Maintaining the upmost purity of our clan is essential to maintaining our demigod powers and our birthright that is Europe. How can we make this possible? [Answer] I feel I should add as a disclaimer that I have moral objections to much of this answer - however morality aside it is a practical solution. Eugenics. Should a pairing produce an undesirable child, sterilize it. (Back in the day they would often just kill the child, sterilization achieves the same result genetically speaking though). Should the same pairing produce a second undesirable child sterilize it force the parents to divorce and form new marriages. Should the same person produce undesirable children on a second marriage sterilize them. Basically it's Selective Breeding but with people, so long as you are ruthless enough you can cull bad recessive genes and mutations out of the herd even while inbreeding. Look into how farmers manage and breed livestock for inspiration. In particular [inbreeding](https://en.wikipedia.org/wiki/Inbreeding). > > Inbreeding is a technique used in selective breeding. For example, in livestock breeding, breeders may use inbreeding when trying to establish a new and desirable trait in the stock and for producing distinct families within a breed, but will need to watch for undesirable characteristics in offspring, which can then be eliminated through further selective breeding or culling. Inbreeding also helps to ascertain the type of gene action affecting a trait. Inbreeding is also used to reveal deleterious recessive alleles, which can then be eliminated through assortative breeding or through culling. > > > [Answer] # Minor nobility Maintaining a bloodline with a limited pool is going to be tough. The trick is to expand the pool without corrupting the main bloodline. What we're going to do here is to redefine the "demigod" to be more like a breed of dog. It's a new breed if it's breeding true for 3-7 generations (depending who you ask). To expand the base pool we're actually going to encourage the young males to sow some wild oats among the local population. These hemi-demigods and their children will be monitored by the administrators of the house via the usual channels of birth and marriage records. Elevating their status to that of minor nobility allows greater control and monitoring of their breeding. The high risk nature of maternity through most of history means this recreation will be denied to the females, they must only breed within the main bloodline. Reproduction within the hemi-demigod and [semi-hemi-demigod](https://en.wikipedia.org/wiki/Sixty-fourth_note) local populations will throw up the occasional true demigod, these should be encouraged to meet through appropriate social events. Should they breed true over a number of generations, their scions will be permitted to breed back into the main bloodline to expand the genetic pool. [Answer] Adoption You mention: > > "Other demigod families throughout the world demean themselves by > frolicking with commoners, inevitably diluting their demigod heritage > and weakening their gifts." > > > This would indicate that there are other familial lines presumably of different genetic stock that also spout from the gods and should have similar gifts. If this is the case then you have a god-like genetic pool to pull from. You don't mention if these other families have same genetic gifts as the Habsburgs (pyrokenisis and long life span) or different gifts (flight? strength? other powers?). If this is the case then I would recommend to do what the great Roman families of old did...[adoption](https://en.wikipedia.org/wiki/Adoption_in_ancient_Rome) into the line and then marrying them into the family. Many of the first Roman emperors were not direct blood relatives of the prior emperor and were often from different and competing great houses of the day. By adopting in the rivals it kept the noble bloodlines pure while still providing genetic parity. Doing this has added benefits 1. Allowing the offspring of their unions to perhaps inherit multiple gifts and increasing the relative strength of the Habsburg line opposite their rivals. 2. Politically tying the other competing houses to the Habsburgs. The Julians and Claudians were tied together in this way. <https://en.wikipedia.org/wiki/Julio-Claudian_dynasty> [Answer] Dear Patriarch or Matriarch of the Habsburg family, Do as you always did: "tu felix austria nube", but try to get some more distant relatives from your big and widespread family clan having children with. Always remember to stay fidel to your partner to keep the line as tractable and pure as possible, such that the distance of relation within the family tree can be reliably determined. Additionally, marry one of the children to some your lesser peers from time to time. The demigod families even of tainted bloodlines are still demi-godly and help restore the genetic pool from time to time which will definitely be valuable for the next generations of your great and powerful house to be able to maintain their marriage politics. [Answer] # In Vitro fertilization Have a team of meisters doctors surgically extract all of Cersei's eggs and fertilize them with Jaime's, Tyrion's and the unnamed brother's sperm. Use genetic sequencing to find out which eggs are bad and discard those. Freeze the rest and pick them for impregnation as required. This should grant you enough frozen embryos to last for thousands of generations. By the way, if you can find the genes for mindless cruelty or pushovery, please cull the embryos with those too. Joffrey was a failure, and Tommen even more so. [Answer] You seem suggesting that the trait you want to preserve is genetically transmitted. Therefore I can think of two parallel approaches: 1. Breed, ahem, arrange marriages with other demigods of proven lineage. That would add some fresh genes to the pool. 2. If you happen to find, among the mass of the commoners, some individual bearing the traits of the demigods (random mutation, you know?), elevate him or her to the appropriate level and pull his/her genes into the pool. For both approaches you can task an ad-hoc organization, which will search and investigate the lineage and the manifestations of the demigod traits, with the major purpose of keeping the lineage pure and holy. [Answer] If the Habsburgs are descended from gods but are still mortal then that means somewhere in their history a god must have frolicked with a mortal to produce the first of the Habsburgs. All of the undesirable recessive genes must have come from that mortal. So just embark on an eugenics program to identify the male and female breeders with the least traces of undesirable recessive genes, and allow only them to breed. This rule must extend to the royal families as well. The rest of the Habsburgs can still satisfy their urges with their family members or outsiders by using condoms or elixirs of spermicides. [Answer] Outcrosses, as in Charlie Stross' Merchant Princes series\. Those directly in line of succession should marry other full-power members of the family. Their younger siblings should be married to people outside the family. Then the nephews and nieces, each hemi-demi-gods, can be married back into the family, with their descendants being on average* hemi-demi-gods, but some of them being more powerful. Those are the ones you marry to the next-but-one generation of heirs. \*in which it's a recessive gene being preserved, but if your fictional world has blended inheritance, the process should still work. ]
[Question] [ In this medieval world, I want to set up a clan system that builds up every kingdom. Every kingdoms will have at least 3-4 big clans/families, each is unique to the theme of the magic they use. For example, clan Warr'og specializes in blood magic. Magic power is inherited, and people know "exactly" how this works. The offsprings will have, on average, the same average power their parents have. > > Parents with 100 and 100 may give birth to children with 90-110 magic power. > > They have a magic scale to measure magic power > > > Of course there will be mutations and special cases, but the system rule is roughly like that. With this system, people will try to marry a strong wizard to increase the quality of their childrens magic power to rise in rank to the top of the society. The society values magic power highly, so there will be a gap between castes. I imagine that the society will quickly create a noble class, which will limit the marriage between people in clans to guard their pure blood and secret magic ability. A noble marrying a commoner will be stripped of their nobility and right and kicked from the clan, because of their "tainting" of the blood purity. Marriage between nobles are rare, because mixing the most powerful pure-blood always results in the baby's death, because of the incompatibility between two very different magic powers. (A powerful shadow user cannot produce offspring with a powerful fire user, for example.) So, people will inbreed only within their clan, and this creates a low-diversity gene pool, which will lead to health problems, so they will eventually be wiped out. With this in mind, is the clan system flawed and not stable? Is there a way to escape the inbreeding, but still maintain the blood purity as high as possible? (Note that it is impossible to get an offspring from marriage of powerful magic users of different school) Related: [This question](https://worldbuilding.stackexchange.com/questions/56198/how-to-negate-the-effects-of-long-term-close-relative-inbreeding-in-a-ruling-dyn) gives a good insight on why inbreeding is bad: because of the possibility of accumulating bad recessive genes. However, it does not address whether the clan will be wiped out by the inbreeding or will it survive (for at least 10 generations)? [Answer] # Oh boy, magic wielding [chinless wonders](https://en.wiktionary.org/wiki/chinless_wonder) Breeding for a single trait always causes issues, as any critic of pedigree dogs will tell you. If you want the society to be stable, you need to allow a level of social climbing. As it stands you have a rapidly decreasing, increasingly unhealthy, aristocracy who aren't going to survive much longer. The thing with surviving aristocratic families is that they rarely let vanity stand between them and survival of the family line for long, if they do they cease to be a surviving family. "Pure blood" is a vanity issue, lack of money and bad genes are a survival issue. In this case you can add magical power to the survival side. In the long run, (money and) power is likely to be the driving factor. A peasant with a bit of power rises a little. A rich merchant's daughter with a lot of power can rise a lot. The father can gain a lot of credit by marrying her off to some inbred scion of a great family in dire need of a little genetic diversity (and an injection of cash). In time the wealthy and magical become junior nobility. Junior nobility can become senior nobility by some great act. Members of the establishment can in time join the aristocracy. The sons of the aristocracy [sow a few wild oats](https://english.stackexchange.com/questions/79648/origin-of-phrase-sow-wild-oats) among the peasants, meaning the occasional peasant crops up with magical power. This allows a little outbreeding in what is otherwise going to become a highly inbred and dying society. [Answer] Genetics Ok, lets model it as Addative alleles. <http://study.com/academy/lesson/additive-alleles-the-additive-gene-effect.html> Some genes also have many pseudo-genes throughout the genome. Some traits are merely affected by many many different genes. So rather than yes/no/maybe it's more like height. It's not a single gene but a trait based on the effects of say, several dozen sites, each adding a variable amount to magical power. Commoners First, unless you have crusades/culls/inquisitions commoners are going to have a low base level of magic. Having even a little magic is just a massive advantage and rich&powerful people always have secret affairs. Children having, on average, about the average of their parents power sounds about right but with quite a lot of variation, sometimes the 2 most powerful mages in the world will birth someone who can't light a candle, sometimes they'll birth someone even more powerful. Political marriages I think you can make this system stable and limit inbreeding by taking into account strategic marriages. Even the most powerful mages will sometimes need allies and marrying off your least magically powerful offspring is a small price to pay for a strong alliance with a magically weak but rich ally. Inheritance Inheritance could could go to the most powerful progeny, not merely the firstborn. This would of course make for a vicious family life since you want to prove you're the strongest to inherit. So your society could look like a mountain rather than a totem pole, the most powerful marrying only the most powerful but surrounded by tiers of almost-purebloods with slightly less power. Occasionally exceptionally strong mages from the lower classes rise up while the weakest from the top families marry down.Rising stars make particularly appealing marriage prospects. Illegitimate children of the very powerful stand to make quite a splash with enough power to catapult them to the upper-middle classes. [Answer] Your magic seems to be genetic related. The following can help escaping the gene bottleneck: 1. random mutations in the commoner population can produce new magic carriers. If they can be recognized (and I guess a toddler setting a bed on fire while burping is a sound hint he has fire magic) they can also be put into arranged marriages to bring new genes into the clan. The clan is then more defined by capacity/adoption than strict blood line. 2. Due to the variance in the breeding outcome, I expect that you can have a Gaussian distribution centered around the average of the two parents. This means that actually you have some more choices when looking for let's say a 90, and not being limited to close relatives. [Answer] The society values magic power highly, so there will be a gap between castes. You're working on the premise that the magicians are the only rich and powerful people out there. This won't be the case though. Traders will mostly be normal. Soldiers will mostly be normal. And since soldiers are mostly normal, it's very likely that the aristocracy will also be mostly normal. If this situation has been around since forever, then everyone will have a bit of low-level magic ability, from before the patterns of magic inheritance were understood. Also everyone will have a bit of ability from every magical category. So you'd need to refine your rules about no interbreeding between commoners and between schools of magic, because clearly that would need a minimum level where it starts to apply. That's a very arbitrary rule anyway - what defines a "fire" or a "shadow" magician? If the magic-users have only just arrived though, they'll be inserting themselves into an existing non-magical society. This creates a serious problem for the society. On the one hand the ruling class can see that these people will be a powerful tool to advance their country's interests; but on the other hand the ruling class are now are faced with effectively an army who could destabilise their own interests, and the peasants are faced with the prospect of even more unaccountable overlords, so there's a very real risk of a mass mobilisation against the incoming magicians. The way this has traditionally been resolved with newly-established power blocs is with marriages between the "old power" and "new power" families to try to de-escalate these problems. This may lead to more randomised magical abilities; or if there is conscious breeding going on then you may get the "braid" concept of arranged marriages from [Charles Stross's "Merchant Princes" series](https://en.wikipedia.org/wiki/The_Merchant_Princes). Either way, the idea of isolated clan families is not at all practical. [Answer] Yes your magic societies would suffer from inbreeding. But you can get some energy for your story from this. [![Elric](https://i.stack.imgur.com/4FpZk.jpg)](https://i.stack.imgur.com/4FpZk.jpg) Depicted: [Elric of Melnibone](https://en.wikipedia.org/wiki/Elric_of_Melnibon%C3%A9). The ruling class of Melnibone in this series are powerful wizards but also very inbred: Elric is an albino and has other frailties that make him reliant on sorcerous soul-sucking magic really to do much of anything. If your mage families are comparably frail and inbred, each in its own way (sun-fearing albinos are fine; some could be very fat and ravaged by hunger, prone to madness or seizures, etc) then you have a downside for their magical upside. The commoner with a normal body and normal abilities might think he has things pretty good! But the outbred and outcast mage / commoner offspring with half the magic ability and none of the inbred downside might have it best of all. Until it is realized that 2 of these halfbreeds can produce offspring together. The F2 grandchild has only a quarter of the magic power of her grandparents, but a quarter of each of her grandparents - one fire, and one blood. [Answer] I think your main problem with prohibiting them from interbreeding with commoners. Take that away and you solve all any issues with inbreeding as the mages will just carefully choose new blood to marry into their ranks every generation. The way to explain this is to look more closely at your system of magical inheritance. A very powerful mage who marries a commoner and has children will have less powerful children, but those children will still be more powerful than most other mages. Let's assume a mage with 100 power marries a commoner with 0, their kids should then have a power ranging between 40 - 60, still pretty high. If two such children marry then they might have kids ranging anywhere from 30 - 70 depending on their individual power. It only takes a few generations to have power 100 mages again with careful breeding. So instead of saying that interbreeding with commoners or the other clans is forbidden I would say that your clans would have a very rigid system of arranged marriages where children are carefully married off to maintain the highest levels of power and the most diverse gene pool. This also helps keep the mage families in power as the lower classes are constantly striving to be seen as worthy to join them and marry one of their members. [Answer] For how long? If the starting parental group is clear of lethal recessive genes then inbreeding can proceed for extended periods, over many generations, the only reason the gentry in Europe started to actively pursue out-cross breeding was that they picked up/mutated a [Haemophilia](https://en.wikipedia.org/wiki/Haemophilia) complex that spread through the aristocracy. Before that the breeding pool had been pretty stagnant for centuries. The longevity of your system would, in my opinion, be dictated by the top end, more powerful mages are generally going to wed more powerful mages because in this set up magic power is political power. in effect the breeding pool at the top is going to be much smaller than the overall size of the magical community would suggest and if a lethal/dangerous genetic complex formed or was introduced into that top end then the collapse could be fast and deadly. This would be especially true if the dangerous defect didn't effect physical fitness, in survival terms, and didn't effect magical power, do the words "mad King" ring a bell. [Answer] According to [this answer](https://worldbuilding.stackexchange.com/a/6/294) you need about 160 genetically diverse individuals to maintain a healthy balance for 10 generations in isolation. If each kingdom has 5 clans, and each clan has 5 families, and there's 5 kingdoms, that's about 125 genetically diverse sources. Considering you'll find random people here and there who either marry well or are able to "prove" their genes to be worth adding to the your gene pool (phrase it however you want...) then you should be fine to prevent inbreeding. It's also possible that each family has sub-families (think duke-to-count-to-baron relationships) where people can marry up from. Someone with a high magic ability, or other very favorable attributes (mediocre magic but high physical strength or intelligence) to add to the pool might find him or herself married to a lordling from the higher up family. And of course, the child prodigies (the Gausses and Mozarts of the world who come from nothing) will find themselves heavily courted both for their obvious current power and future sustainment of a guild. Alternatively, magic people don't suffer from inbreeding because magic. =) [Answer] There are a few things that you're going to have to "relax" a bit. > > Parents with 100 and 100 may give birth to children with 90-110 magic power. > > > Ok, but let's say a non-magic and a magic user (100) mate, then the scale could be something more like 0 - 90. That wide range is why.... > > A noble marrying a commoner will be stripped of their nobility and right and kicked from the clan, because of their "tainting" of the blood purity. > > > They made a weaker child. There was no chance to make a stronger one. That is why it's frowned on. But the clan, understanding the importance of new blood, allows the child to stay part of the clan. They are adopted by another family, and raised as if they were full blood. After a couple of generations everyone will forget that the bloodlines mixed. In fact, knowing that they need new blood clans "compete" to recruit "commoners" that somehow were born with magic into an adoption arrangement. Once adopted they are full blood. Of course fire clans can only adopt fire commoners. As a later reveal, side plot, or whatever, you can show that all the "commoners" with magic are just from the nobles not knowing how to keep their pants zipped, and being horrible parents. You could even show how "dads" get away with it more, because it's much easier to hide "borked a tavern maid" then "impregnated by a stable boy". You get your fresh blood, a new hypocrisy to explore (that mirrors RL close enough to count) and a stable system built on a nice plot-able lie. [Answer] Hmm ... how closely can these people rate one another? Can they boil it fairly accurately down to a number like you do above, or is it more of an impression ("Hey, she's strong!")? In either case, if you don't want a story about decaying clans of inbreds you'll need some genetic/social mobility. So you might have a notion of the clans -- or families within clans -- scooping up the most talented children of the next tier down. This serves a dual purpose: first, you get fresh genes; and second, each tier is stopping the lower tiers from breeding up into a position of parity with their social betters. There's plenty of story-fuel in these marriages. Do the talented scions of Clan Unter desperately want to "marry up" into Clan Uber? Or does Clan Uber coerce the resentful Unterites into giving up their beloved children to forced marriages? You could have both dynamics going on at once. In the same vein, can you get "demoted" into a lower clan? Can a sneaky youngster conceal his power level, seeming either higher or lower than his real level? Plenty of possibilities here. [Answer] There are two opposing dynamics. It helps society as a whole for strong males to spread their seed far and wide. In such a society, marriage would be highly regulated but bastards would be common and would hold mid level positions in the rest of society (they are stronger than most people but not strong enough to threaten the full blooded mages). It helps the clan to have all the power within the clan. Therefore, they would resist any any "magical genes" being spread outside the clan. The men's interactions outside the clan would be much more highly regulated. The reasoning there is that half breeds might not be as powerful but quantity has a quality of its own. The best of both worlds would be to set up the half breeds under the umbrella of the clan. Give them power over commoners and keep a tight reign on them. You can do this by having competitions to become an "outer disciple" of the clan. Make them work for it. Then, most half breeds (and the few spontaneously generated commoners) will try to become part of the clan. [Answer] There needs to be some kind of acceptance from the outside. Possibly commoners with innate magic abilities. They are unaware that they have these powers, but it can be discovered with this magic meter you have. Also, you said there are mutations, so it could be possible that a non-magic born commoner has innate magic powers. It could be a thing that these clans need for survival and thus highly regard commoners that have magical abilities. ]
[Question] [ In the course of events in my world (tech = 1920-ish, but no airplanes. Maybe blimps.), a large archipelago nation is invaded by a naval superpower. The archipelago nation, which had been developing aircraft in secret, engages its airforce and wrecks the enemy fleet. Is this possible? More specifically, is it possible for aircraft to be developed, in secret, to a 1930-ish level of capability? This also includes having trained pilots who are able to pilot these aircraft. No relevant magic is involved. [Answer] Even in the open, with no secrecy, it would be difficult to develop an airforce capable of destroying an enemy fleet from scratch. No "1930-ish" airforce was capable of it. (Ships in harbor were easier targets, as at Taranto and Pearl Harbor, but ships on the open ocean are much more challenging. 1930s aircraft could hurt a fleet, but not destroy it.) During the 1940s, Allied air forces developed the ability to consistently bring down Japanese fleets but this was a painstaking process involving refinement of every part of the force: planes, munitions, pilots, reconnaissance, communication, fleet command, ground crews, and countless other factors had to come together to make it possible. That's not a development you can really replicate without some hands-on experience of trying, and often failing, to take down ships under real combat conditions. If you don't have that real-world experience, you can try to simulate it with wargames and training against static targets. However, this would be difficult to engage in secretly because of the scope and size of the exercises. Remember you're not just training pilots to make attack runs - there's a whole process of locating targets, launching and guiding squadrons on the attack, and recovering them afterward that has to be meticulously practiced. Even your ground crew - you can't launch hundreds of sorties rapidly if your crew isn't experienced. You'd need airbases to stage out of, ships to "engage", derelicts to blow up (you'd be amazed how hard it is to make a torpedo bomb that detonates reliably!), the works. Proficiency in these kinds of attacks doesn't just happen, it's a huge job to make it happen. Too huge, I think, to feasibly keep it secret. And there's a political angle, too: the whole point of an unstoppable airforce is to not be invaded in the first place because of its deterrent value. That's lost if you keep it a secret. [Why didn't you tell the world, eh?](https://www.youtube.com/watch?v=j83bGaauRXw) [Answer] Consider the secret German rearmament programs of the 1920s. By the Versailles treaty, Germany was forbidden to develop certain armaments. Russia was another outcast of the international system at the time, and [after the Treaty of Rapallo](https://en.wikipedia.org/wiki/Germany%E2%80%93Soviet_Union_relations,_1918%E2%80%931941#Treaty_of_Rapallo_1922_and_secret_military_cooperation) German engineers went to work in the Soviet Union. * There was no attempt to hide the fact that aircraft could exist in principle. This cuts both ways, unidentified flying objects cannot be passed as ordinary civilian planes, but agents of enemy nations would not know the telltales of an aviation parts industry. ("Interesting, they are building compact, powerful engines. Any indication that they are going into armored fighting vehicles and not just trucks?") * The capability of Japanese naval aircraft to drop torpedoes in shallow water came as a surprise to the US, even if it [should not have been](https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor#Retrospective_debate_on_American_intelligence) quite as surprising. Again, intelligence was looking for indications of the things they were familiar with, not sufficiently thinking out of the box. * It would probably take several generations of aircraft until they were capable of hurting ships at sea. From the early contraptions of the Wright brothers, over the [Short Admiralty Type 81](https://en.wikipedia.org/wiki/Short_Admiralty_Type_81), to something like the [Fairey Swordfish](https://en.wikipedia.org/wiki/Fairey_Swordfish), the generations required not just time but also practical experience. Much harder to leap to something like the Swordfish on exercises alone. On the plus side, the absence of a known air threat means that ships will not be designed with AA weaponry. Trying to hit an airplane with [anti-torpedo-boat guns](https://en.wikipedia.org/wiki/BL_4-inch_Mk_VII_naval_gun), ammunition, and training would be challenging. Your fictional naval power might have better anti-torpedo-boat guns on their ships, which might mean bigger and hence slower-firing. So you would have to have (1) the recognition of the potential of air power, with the decision to keep it secret, (2) a decades-long R&D program, with realistic exercises trying to sink target ships, and (3) a secret production and deployment program. Think of the [F-117 stealth fighter](https://en.wikipedia.org/wiki/Lockheed_F-117_Nighthawk). The US managed to bury the program in their defense industry, details were muddled but rumors were there. You would stretch credibility, but perhaps not break it. Especially if problems and limitations do show up. Say the first operationally deployed squadrons are both limited in number, and unable to hit a defended targets. During the first battle, a few are hit by the anti-torpedo-boat armament, most get into position to drop their torpedoes, and a few hits are scored. Maybe 100 planes on the attack, 5% aborted or lost at sea, 5% shot down prior to the torpedo drop, 5% shot down after the drop, 5% don't make it home. There are 90 fish in the water. Say a 10% hit rate, and you get 9 torpedo hits for 100 aircraft sent out, a bit over 80 coming home. Those 9 torpedo hits managed to cripple 4 or 5 capital ships. (The pilots were trained to go in close, no torpedoes wasted on something like a destroyer. Also, short-range torpedoes to allow bigger warheads. And the enemy captains were under order to hold formation until the admiral sends 'torpedo boat attack, maneuver independently.' That permission never came.) In the second battle, the 80 survivors go in, 75% of them are shot down prior to their drop because there are now machine guns on the ship. (Remember, the pilots were trained to go in close to compensate for slow and erratic torpedoes.) The warships have learned to evade more quickly, without orders from the flag, so the 25 torpedoes score 4% hits, i.e. a single one. Which damages but not sinks a cruiser. The survivors report, the designers design, and in the third battle a new torpedo is deployed, with sufficient range to hit from beyond machine gun range. Also, the aircraft squadrons have learned to attack simultaneously from different directions, so that turning into one group of torpedoes exposes the broadside of the targets to the other. And so the circle turns. [Answer] What are your long-distance surveillance technologies? L.Dutch has already mentioned one: sound. Sound travels a lot further than the human ear can hear, The first patent for a microphone was in 1877, so by the mid- to late-1920s it's more than possible to set up "listening posts." The technology would be cumbersome and humans must be trained to "filter" out the noise that was uninteresting (wind, waves, commercial traffic...), but it could be done. If there was a reason to listen that closely. The second long-distance surveillance technology of the day was telescopes. The [100" Hooker telescope on Mt. Winston](https://www.mtwilson.edu/observe/) was the largest in the world from 1917. That's a big honking telescope, and while used to view the stars, there's nothing to say (other than it would be whomping impractical to use) that it couldn't be leveled at your target civilization to watch closely what they were doing. You could see a lot with a 100" telescope from almost any distance so long as planetary curvature and intervening geography permitted it. If there was a reason to look that closely. Your best friend is working where you can't be seen or heard Knowing nothing about your planet, let's assume that there's a side to the archipelago that faces the invading nation and the other side that faces open sea to the horizon. Bully! You can operate your test programs on the sea-side of the archipelago almost with impunity. Caution is always required. Movement between the islands could be done by flying your craft in twilight hours, taking advantage of the heightened "optical noise" of the sea surface to hide your craft from prying eyes and keeping the sound of any engines as near to the surface as possible to mix it with the "auditory noise." It's not a guarantee of not being seen, but it would go a long way toward it. Your people might even master night flying — but that's more of a stretch. Night flying in the days without radar on the planes was very, very difficult, especially for navigation. Which means your biggest problem, as usual, is espionage Everything I've said describes what you could do to hide your project from casual observers at a distance and what those observers could do to overcome those limitations if their attention were drawn to the island. What I've described is unusually extreme. There's no historical analog that I'm aware of that reflects the level of effort I've described. Which means you need to be sure not to give anyone a reason to be extreme. A healthy counter-espionage program is a necessity to make sure even a rumor of your program stays inside your borders. It's beyond the scope of Stack Exchange to describe such a program in any detail... but I'm sure [spies will be involved](https://worldbuilding.stackexchange.com/q/209717/40609). Conclusion Yes, it's possible. Given clever use of geography, chronology, planning, and paranoia... it could be rationalized. [Answer] To develop an air force in secret you need to keep the information away from those for which it has to be a secret. Considering that planes flying around will be seen/heard, you would need something like the Area 51 base, in the middle of a remote area, with strong security around it, to really be secretive. Even better if you had something like bases in the steppe, like USSR did. The more remote, the better. But that is going to be pretty difficult on an archipelago nation. And the more effort you put into preventing people from seeing/accessing the base surrounding, the more the curiosity of interested agents will be tickled. However difficult doesn't mean impossible. [Answer] Yes and No. This line: > > "tech = 1920-ish, but no airplanes. Maybe blimps." > > > Makes me say 'No'. A lot of answerers have quite rightly pointed to pre-WW2 Germany and how they trained an airforce in secret - however, they have omitted one key point - the reason Germany was able to do this was due to the extensive German gliding Clubs that existed from the 1920s onwards. This ensured that there was an extensive knowledgebase of aviation understanding and piloting skill. In the 1920s, heavier than air flight was already well established and understood and so a Gliding program wouldn't (and didn't) raise any eyebrows. So - if heavier-than-air flight is unknown in your world building scenario - we have a pretty big hurdle to get over. We can't have a cadre of trained/skilled pilots. Unlike Germany, we don't have a population base with all of the transferrable skills needed to pilot a powered aircraft. And the problem here is that the skills required to pilot an Aircraft (or simply navigate in 3D space) are pretty unique. If we look at other secret projects in history (say the various exploits of the Skunkworks) - there's a significant amount of overlap from ordinary aviation - meaning that the development of the niche/specialist skills represents a small fraction of the overall skills needed - The SR71 had the challenge of getting your head around the speeds being travelled at (you've never been lost until you've been lost at Mach3) - but that's merely an enhancement to the existing skill of navigating an Aircraft. The development of Heavier-Than-Air flight is such a groundbreaking achievement that I doubt it would be possible to be kept secret. However... 1920s Ships - the amount of AA Firepower they wielded could be summed up as 'Non-existent to Pitiful': Ma Deuce didn't really exist in the 1920s - and wasn't widely adopted until the 1930s. Oerlikons didn't exist in the 1920s. Dual-Purpose 5-inch/38-caliber gun didn't exist in the 1920s The Bofors gun didn't exist in the 1920s. And perhaps most importantly of all... Proximity fused Projectiles didn't exist in the 1920s either. Now - to be fair - all of the above (except the proximity fused munitions) came into being in the mid-1930s. What you see a lot of in WW2 is that various ships that initially had little to no Anti-Aircraft armament got retrofitted in the late 1930s or after the likes of Pearl Harbour to get a significant upgrade to their anti-air capability. Also - to be fair - the threat level of 1920s era aircraft is likewise miniscule - they are almost exclusively biplanes (insert Fairy Swordfish British Meme) with very limited bombing capacity... But we have to take a pause here and talk about the 1921 American Airpower test - where TL;DR - a number of ships were attacked by Aircraft in a trial - the initial payloads of WW1 size bombs (100Kg, 600 Pounds sizes) proved to be ineffective - but Billy Mitchell (absolute legend) arranged for 1000 and 2000 pound bombs to be dropped - and with 3 near hits under the waterline to a captured German Battleship - they were able to sink said Battleship (although this test was highly controversial for a number of reasons - the Navy asserting that a well-trained Damage Control party would have prevented the sinking). However - we must consider that the above test took place after the advancements in air-power that were driven by WW1. I will add a little aside here - In WW2 - most of the anti-ship dive bombers ended up using old Battleship calibre Armour Piercing Shells (12 inch, 14 inch etc.) with some modifications to turn them into bombs. Whilst this was done in WW2, so 1940s tech, the actual munitions used were older variants of Battleship shell - Essentially all those pre-Treaty (The washington Naval treaty - I think 1926?) Calibre shells. Since the shells exist in the 1920s - I'm allowing it. To Conclude From a pure 1920s technology perspective - most of any naval Superpowers ships are going to have very limited Anti-Aircraft firepower. It is possible, with 1920s Technology to successfully sink a Capital ship. That said, most of this innovation came about from the results of WW1. Furthermore - the most effective Anti-Ship weapon (Modified Battleship AP shells converted to Bombs) sort-of existed. However - without a means of training pilots or at least having a segment of the population with enough transferable skills to be able to do this all in secret is a big stretch. My suggestion: Have gliders exist in your story, but make powered flight unknown - this allows you to solve the problem of having Pilots. You could also introduce a sport whereby Glider pilots practice dropping things from their cockpit, to see who can get it closest to a target. Now you've got the skills, you've got aerodynamic understanding - your countries key advantage is making an Aero Engine (light and powerful enough) - you could still keep this secret as you could have the planes cut the engines when coming into land. [Answer] Just focusing on "build it in total secrecy" part, that could be tricky if the opponent isn't so reckless as the invade without any meaningfull scouting prior to the invasion. An archipelago is both a blessing and a curse. On the plus side, you probably could base your airbases, and perhaps even the production facilities, on a remote uninhabited island. That limits the risk of spies visiting your population centers seeing strange flying machines. The downside is, there is a small and (assuming our 1920's knowledge) known list of islands the enemy would have to check once they notice the large and inexplicable resource shipments you're sending around. It seems unlikely that an island with access to all construction and fuel resources, and enough space to put the whole supporting infrastructure, would have remained uninhabitted for so long. And even then, you'd have to send a large number of workers to these facilities, which can also be relatively easy for spies to find out. And a 1920's era navy probably has submarines that can have a discrete look around various islands prior to the invasion. I find it probable that one of those subs will spot some airborne planes. Other anwers already mentioned the large amounts of exercises neccesary to develop not just the planes, but the technique and doctrine to threaten a navy at sea. So there'll be a lot of flights from and to your training airbases, any one of which can be spotted. The airforce might be able to spot the enemy scouts in turn, but they probably won't sink them outright if there is no war yet. And even if they do, recon assets vanishing in a certain area is a very clear indication that there is something dangerous to your navy in that area. Bottom line, if the enemy isn't suicidally overconfident or inept at scouting, they should be able to find out that your nation has new technology that lets their warmachines fly. ]
[Question] [ Is there a way to sharpen stone weapons? In a society with no metals whatsoever, which is therefore using stone for their weapons, can the cutting edges of those weapons be sharpened? [Answer] Absolutely, yes. Historically (and prehistorically), most sharp stone tools (projectile points, scrapers, knives, etc) were made from obsidian (volcanic glass which lacks a crystalline structure), cryptocrystalline silicates (cherts, such as flint), or fine grained volcanic rock (e.g. fine-grained andesite). Generally speaking, when one wants to make a new tool, the maker will use the percussive force of a stone against a "core" of toolstone to knock a roughly tool-sized flake off of the core. The flake is then be shaped and sharpened via percussive flaking (hitting the tool blank with a rock or antler to knock off smaller flakes), and is ultimately sharpened using pressure flaking (pressing the tip of an antler or dense stick into the tool to knock off small flakes)[1]. The flaked edge can be incredibly sharp (e.g. obsidian flakes to blade whose cutting part can often be measured in atoms of thickness; ages ago, when I was actively learning to make stone tools, I sometimes shaved with obsidian flakes). This general process is called flintknapping. As a knapped tool is used, the edge will wear (as flakes are knocked off in a non-systematic fashion). The edge can be refreshed by using the same knapping technique as is used to construct the tool in the first place. A great reference for the practice of flintknapping is Dr John Whittaker's book [Flintknapping: Making and Understanding Stone Tools](https://www.google.com/books/edition/Flintknapping/21SBAAAAMAAJ) (disclosure: John is a good family friend; the book was illustrated by my mother—that said, it is an authoritative text in the field). That being said, it is likely that stone weapons will come in one of two general varieties: projectiles (like atlatl darts or arrows), and "bladed" weapons with stone blades embedded into a more durable medium (such as the Mesoamerican [macuahuitl](https://en.wikipedia.org/wiki/Macuahuitl)). In either case, using the weapon is likely to either leave the stone parts relatively unaffected, or to completely break them. It is unlikely that one would seek to sharpen the edges of such a weapon, and more likely that one would simply replace the stone parts (i.e. replace the obsidian blades of a macuahuitl). Stone itself is generally quite brittle, hence one would not expect to make a weapon entirely out of stone (e.g. a stone sword would likely be quite useless, Minecraft notwithstanding). --- [1] It is worth noting that stone tools can be quite useful, and that, for example, it is possible to buy [obsidian surgical tools](https://www.finescience.com/en-US/Products/Scalpels-Blades/Micro-Knives/Obsidian-Scalpels). [Answer] ## Yes. When a flint or other stone blade becomes dull, it is sharpened by either gently chipping flakes off the edge (as was done in final shaping for shaped blades) or sometimes by rubbing the edge on another stone to wear away the dulled "points" of the natural serrations in a shaped edge and expose the unworn "throats" of the individual chips that formed the edge. The only stone tools that can't be sharpened to original capability are flake blades -- and these are quite primitive types that are usually replaced (as a culture's knapping tradition evolves) by shaped tools that can be hafted and last better. [Answer] You can sharpen stone tools with sharpening stones. <https://www.youtube.com/watch?v=BN-34JfUrHY> [![sharpening axe](https://i.stack.imgur.com/nhYWX.jpg)](https://i.stack.imgur.com/nhYWX.jpg) I like this Primitive Technology series. Here Mr. Plant makes a basalt axe head then sharpens it with progressively finer stones. It is much the same as one would do with a metal tool. In the same video he makes a chisel from mudstone (which I would not think would make a very good chisel) and proceeds to cut down a tree with it. The chisel is sharpened with grinding on other stones, just like the axe. [Answer] Never heard of [obsidian blades](https://www.homestratosphere.com/obsidian-blades/#:%7E:text=Obsidian%20blades%20were%20often%20found%20with%20the%20remains,require%20the%20tool%20to%20be%20sharpened%20into%20anything.)? > > Obsidian is a confusing element. It cannot be considered a mineral, because as a glass it is not crystalline, whereas minerals are. But at the same time, it is classified as a mineraloid, since it has mineral qualities, but they are too variable to be pure mineral. Get it? Me neither. > > > First Encounters > The first-ever known historical use takes us into the Acheulean age. This age is classified through the first practices of stone tool usage. Obsidian blades were often found with the remains of Homo erectus, and it is believed that these technologies developed nearly 1.76 million years ago. > > > The way that obsidian fractures are so sharp, that it wouldn’t even require the tool to be sharpened into anything. > > > Or, similarly, never heard of [flint](https://en.wikipedia.org/wiki/Flint)? > > Flint breaks and chips into sharp-edged pieces, making it useful for knife blades and other cutting tools. The use of flint to make stone tools dates back hundreds of thousands of years, and flint's extreme durability has made it possible to accurately date its use over this time. Flint is one of the primary materials used to define the Stone Age. > > > If there is still enough body remaining, you can simply chip it some more to sharpen the edge. ]
[Question] [ I am looking to create a scenario in which the nobility and peasantry of a medieval kingdom speak the same language but different versions/dialects. Scenario parameters: * The nobility can understand the version the peasantry speak * The peasantry cannot understand the version the nobility speak (they may be able to pick up bits and pieces) * Stems from a single language (this should be different from historical examples like the English nobility speaking French while the commoners spoke English) * The scenario should NOT require a massive government oversight program. We are talking about a medieval kingdom, there weren't exactly public schools. * Most commoners cannot write (though a few among the merchants are able) Is such a scenario possible? If yes, how? [Answer] There is no doubt that two dialects of a language can be spoken in the same area, i have seen it in the same village. But there is a problem with your question. If two "dialects" are so different that the speakers of one could not understand the other, then generally they would be considered two different languages, not dialects, at least from a linguist's standpoint. However political/cultural/historical factors sometimes take over and things are called dialects that a linguist would call different languages. So what we are talking about, from a linguist's perspective, is really two related languages. They are related enough and have enough cognates that the speakers of L1 can understand L2, and speakers of L2 can catch a few bits here and there but cannot understand L1. This is not only possible, but actual fact. Consider Latin and Italian. If my understanding is right, Latin is the official language of the Vatican, but that just means that this language is reserved for especially important or official business, while Italian is often spoken throughout the Vatican and of course Italy. Your average Italian will not understand Latin, but because the two languages are strongly related to each other, he can catch bits here and there. Your average high ranking church official in the Vatican will speak both Latin and Italian fluently and be able to read and write both. Not exactly royalty and commoners, but a useful parallel. Also take Koine Greek and modern Greek. The more educated a person is in modern day Greece, the more they will understand Koine Greek (ancient Greek, used in the New Testament), especially if they have any knowledge of classical Greek. But an uneducated Greek of today would gets bits from a person speaking or reading Koine Greek, but would get easily lost. And today there are people who learn Koine Greek (myself included), and can read it and understand it, but cannot understand modern Greek. There are also people, I expect, in Greece who have learned enough Koine Greek to be able to speak it fluently and read and write it (probably in the analysis and discussion of ancient documents, including the NT) and who are also fluent in modern Greek. I hope you see the pattern - education. It would be easy to conceive a world in which only the nobility are educated. Because it is a medieval world, documents are not publicly available, and books and libraries are rare and only maintained by the wealthy nobles. Because there is no printing press, the language shifts - like happened to Greek and to English. Try to read John Wycliffe's translation of the Bible and you will not be able to understand it (Middle English) but read the Tyndale Bible (translation done just after the printing press - modern English) and you will have no problem. But in this world, the nobility decides that their education must all be carried out int the ancient form of their language, the one used for their most sacred documents, perhaps the very documents that established them as nobility. A noble must be able to read and understand their letters of patent, and all official business is conducted in the language of those patents of nobility. The uneducated commoner is lost. He catches a word here and there, but not more. The educated noble understands every word. [Answer] # Yes. In Arabic, the TV News and Academic Arabic speakers (usually) use Modern Standard Arabic, whereas in every Arabic country, a colloquial version is spoken. This seems to achieve the strata effect you're looking for: the Academics and the Informed speaking in a totally different dialect than your every-day Joe (or every-day Ahmed, or whatever). Of course it is not that concrete and universal, but a rule of thumb. EDIT: As per PipperChip's comment below, apparently high German and local dialects differ as well (thanks). It seems like almost any culture large enough will have differentiation in dialect, but there are a few good examples where the 'upper' group and 'lower' group - being very rudimentary with my language - is separated. I grew up in Germany and don't remember it; maybe I was the lower group! [Answer] You don't need to go back to medieval times. When [Emperor Hirohito announced the end of World War II on the radio](https://en.wikipedia.org/wiki/Gyokuon-h%C5%8Ds%C5%8D), he did so in a classical Japanese that could not easily understood by all except well-educated elites. The emperor's dialect had fallen out of use for at least a generation, even among the nobility. Therefore, the broadcast of the recording was followed by the radio host's explanation of what everyone just heard. The disconnect is possible because hardly anyone interacts with the Japanese emperor directly. That rare direct voice communication was necessary since the populace would not have accepted any other kind of announcement, due to their fervent loyalty. Even today, the Japanese imperial court remains rather secluded — [Emperor Akihito's first nationally televised speech was in 2011](http://www.washingtonpost.com/wp-dyn/content/article/2011/03/16/AR2011031602760.html) — 22 years into his reign. I'm not sure how your last condition is related, though. The [literacy rate in Japan in 1945](http://itre.cis.upenn.edu/~myl/languagelog/archives/003962.html) was rather high. [Answer] ## Yes Javanese (from the Indonesian island Java) has several distinct vocabularies: * High Javanese for upper class speaking to eachother * Low Javanese for lower class speaking to eachother * one for upper class speaking to lower * one for lower class speaking to upper * two more for special use (religion I think) In addition there is Indonesian, similar to Malay. Obviously, learning several vocabularies takes a lot of education, so the lower class understood only low Javanese, with the smart ones learning to speak with the upper class in the proper language for that, gaining some prestige from that. Since lower class speaking High Javanese was seen as raising oneself above their class, it received a universal negative reaction. This by itself prevented anyone from getting fluent in it. Compared to this, having only 2 varieties sounds easy. [Answer] Sure. An education system conserved the written language as it was, say, 10 centuries ago, and the literate people study it and are fluent in it. Meanwhile the spoken language naturally evolves. Low class illiterates only speaks the modern form. Nobility masters both. Being proud in their ancestry (deeper you can trace, more respected you are) they actually prefer to use an ancient form when speaking to peers. [Answer] Consider the [Kagoshima Dialect](https://en.wikipedia.org/wiki/Kagoshima_dialect) within Japanese. One of the effects of the variation in pronunciation centuries ago was that it was very hard for people outside of the area to infiltrate into the region because the phonetics were quite different. Education wise, only standard Japanese is taught, so younger people sometimes have trouble understanding their own grandparents! While serving in Northern Japan, I once witnessed the unusual occurrence of an American (who spoke Japanese and could "hear both") translating for two Japanese people, one who spoke Kagoshima, the other a more standard pronunciation because the two native (Nihonjin) Japanese couldn't understand each other. Several years later I saw a younger person who lived in Sendai completely misinterpret the meaning of an older woman who spoke "Nambu-hogen" a slightly more rural but nearby Japanese dialect that I was more familiar with, and yours truly was the translator. It happens! [Answer] Yes, by intermarriage, cultural exchange, and war. In the medieval state of Loucha, the nobility (upper class) have retained power in the same way that many rulers in medieval/Renaissance Europe retained power and stability: through intermarriage. In Loucha, this is simply more common lower down in the ranks, as it were. The Louchan nobility is closely related to the nobility of Helko, after many years of intermarriage during years of prosperity during an alliance between the two states many years in the past. This family tree has led to many upper-class Louchans speaking Helkese as a secondary language, to be used diplomatically while in Helko and while conversing with the Helkese people. At home, however they prefer to speak Louchan, their primary language. Over the years, the Loucha nobility begin to "borrow" Helkese words, either because of convenience (Louchan is not a language of monosyllables by any means) or perhaps simply because they preferred the tones of Helkese words (Helkese flows off the tongue fairly well, even for non-native speakers). These Helkese [loanwords](https://en.wikipedia.org/wiki/Loanword) soon become a part of Louchan vocabulary. The structures of Louchan and Helkese are quite different, so it's tough to simply combine the two into one language. Therefore, the two never really merge in Loucha. The nobility simply stick in Helkese words when it becomes convenient. Over time, however, these Helkese words are modified slightly - to fit conjugation/declension needs, to make adjective/noun agreements better, or for any of a number of reasons. Eventually, the two nations go to war against one another, and the noble families on both sides separate from one another. Lounchans stop speaking pure Helkese. However, the modified Helkese words have become so embedded in upper-class Louchan that the past few generations of nobility use them synonymously with other Louchan words, or prefer them over Louchan words entirely. The peasants will have a hard time understanding the Louchan nobility, especially as the peasants are rapidly dying in the war and have no desire to learn a new dialect. [Answer] In interwar Wilno (now Vilnius) the upper strata spoke High-Polish, while the working class spoke a dialect which (iirc) was called "po prosto"(?) I spoke to an Elderly Pole with roots in the region, his mother (a school teacher) always chided his father for speaking Wilno dialect and tried to stop him using it as it was considered "backward" and did not have the prestige of High Polish or Lwow Polish [Answer] The short answer is yes, in a few ways: * Vocabulary. The nobility can understand the peasantry because they use "small words", suitable for the business they need to conduct. The nobility, with access to higher education, has a higher level of vocabulary ("I'm disinclined to acquiesce to your request") that can befuddle the peasantry. The FLDS cult uses this trick, speaking in fairly arcane legalese to trick outsiders and women to gain advantage in debate or negotiation. * Accent. The nobility could speak with a cultured but highly colored accent that is unintelligible by the peasantry; the peasants, in the meantime, might speak in a clearer accent. This is actually the reverse of how it normally works, though the upper crust in many English-speaking cultures have an affected accent identifying them as such (and making them sound like pretentious jackasses to the 99.9%). As I mentioned in the comments, fairly easy-to-transit regions of the British Isles have local accents that are completely unintelligible even to other Brits. * Context-dependent content. The nobility might use metaphorical or other context-dependent references, like inside jokes, that someone else "in the know" (other nobility) would get, but would go right over the masses' heads. This by itself wouldn't be sufficient to obscure the nobility's language, but British cultural references like Cockney rhyming slang have produced common "synonyms" for fairly heavyweight insults that are acceptable on American TV primarily because American audiences have no clue what the person was just called. [Answer] Just for entertainment (this doesn't quite match the poster's criteria), there is at least one [Australian aboriginal language](https://en.wikipedia.org/wiki/Yanyuwa_language) with separate (and quite distinct) dialects for men and for women! > > Yanyuwa is unusual among languages of the world in that it has > separate dialects for men and for women at the morphological level. > The only time men use the women's dialect is when they are quoting > someone of the opposite sex, and vice versa. An example of this speech > is provided below: > > > (w) nya-buyi nya-ardu kiwa-wingka waykaliya wulangindu kanyilu-kala > nyikunya-baba. > > > (m) buyi ardu ka-wingka waykaliya wulangindu kila-kala nyiku-baba. > > > The little boy went down to the river and saw his brother > > > [Answer] How about Haiti, where French and [Haitian Creole](https://en.wikipedia.org/wiki/Haitian_Creole) (a language derived from French, with extremely high overlap in cognates, i.e. related words). French is the main written, administrative, and press language and is spoken by all educated Haitians. It is used in schools and business. About 40% of Haitians speak French. Almost everyone in the country can speak Haitian Creole. [Answer] It is not only possible, but easy. You have to realise that standardizing language took a lot of efforts, and was greatly helped by the use of the radio or the television (one language for everyone in a country, more or less). As a very revealing example, when the French revolution occurred, [more than 80% of the population of France](https://fr.wikipedia.org/wiki/Fran%C3%A7ais#Sur_le_territoire_fran.C3.A7ais) did not speak French but other dialects, part of them also coming from Latin, as occitan language (sorry my reference is in French, I did not find the information in English). In fact until the [ordinance of Villers-Cotterêts](https://en.wikipedia.org/wiki/Ordinance_of_Villers-Cotter%C3%AAts) (1539) the language, in France for official matters was not even French, but Latin. During middle age the language of the jurists, scientists, philosophers and priests was Latin. So actually a given elite used a language not understandable for the commoners during most middle-age, in Europe. Moreover, a category of the population can create a new dialect in order not to be understand by the others. One example is [thieves' cant](https://en.wikipedia.org/wiki/Thieves%27_cant). It looks like slang is more often used by the commoners, but it proves possible for a given elite which do not want to be understand to develop a new language. [Answer] In imperial Russia, courtiers spoke French to each other; I guess they spoke Russian to non-nobles. Until the Renaissance, Latin was the inter-language for educated Europeans. (One scene in Shakespeare begins with a queen of England, iirc, telling a minister to drop the Latin.) Mandarin Chinese is so called because when foreign traders came to China's port cities they found the bureaucrats speaking a different language from everyone else. ("Mandarin" is from a Portuguese word for bureaucrat.) They say that a certain village in India has three languages, one of which is unrelated to the other two, though their grammars have converged (in perhaps the world's smallest Sprachbund). Each of the three is the common language for some purposes, e.g. one is for commerce; thus everyone in the village can speak all three. (Presumably the functional division reflects a caste division, i.e. the merchant caste spoke a different language from the farmer caste.) It shouldn't be hard to tweak this system for an asymmetry. LATER: The village is on the boundary of Maharashtra and Karnataka; the three languages are Urdu, Marathi and Kannada. It's known in the literature as Kupwar, though apparently this is not its real name. (There is a real Kupwara in Jammu & Kashmir, a long way from Dravidia.) [Answer] China, before the government imposes teaching everyone Mandarin. There are many local dialects, they are not mutually intelligible. The words and grammar are identical, though--I would not call them separate languages. People who had to deal with people outside their own domain would learn other dialects, the average man would not. ]
[Question] [ So this is for the same story as my ["Boats for tall people"](https://worldbuilding.stackexchange.com/questions/115199/boats-for-really-tall-people) question earlier, but not about boats. In this world there is one religion that almost every race has a different interpretation of. For example: The really tall people of my last question, the Cellene, believe that the islands are different gods who are the children of the mother god, the ocean. They believe that it is their job to care for these islands to the point they give up things, like more expensive food and they live in houses made from the branches of trees. Well the Meyra, another race, believe that the islands are the sinful parts of pure mother ocean along with other Meyra who pure mother ocean believed so foul that they were cast from her embrace. Now all religions are based on the idea of an ocean goddess who created the islands, each religion has a different interpretation of what the islands represent. They also believe that the religion of the other races is very heretical and is not to be tolerated at all. Would it be possible for them to find a way for the majority of people to peacefully coexist? [Answer] > > Now all religions are based on the idea of an ocean goddess who created the islands, each religion has a different interpretation of what the islands represent. They also believe that the religion of the other races is very heretical and is not to be tolerated at all. Would it be possible for them to find a way for the majority of people to peacefully coexist? > > > # You probably can't fix this long-term You explicitly deny that they should tolerate the others' existence at all, which kneecaps the [majority](https://worldbuilding.stackexchange.com/a/116129/35633) of the [answers](https://worldbuilding.stackexchange.com/a/116135/35633) being [upvoted](https://worldbuilding.stackexchange.com/a/116122/35633). Religiously, you could get angry begrudging coexistence by * Believing the other race is specially protected and marked by the divine ([à la Cain](https://en.wikipedia.org/wiki/Curse_and_mark_of_Cain)). They're a stain and a mistake, but they have a role in Creation and are to be left alone. * Believing the other race is specially punished for their sins in earlier lives ([à la the Dharmic faiths](https://en.wikipedia.org/wiki/Karma)). Their estrangement from the true faith is part of their fallen existence, but should be mostly accepted. The good ones will eventually be reborn as the Chosen Race like we were. * Believing the other race is going to be specially punished and this is all part of the Divine Plan ([à la Calvin](https://en.wikipedia.org/wiki/Predestination#Calvinism)). The damnèd other exists only to better guide the Righteous, who continue upon their path knowing that vengeance for their many blasphemies is the Lord's. * Believing we've moved past those silly superstitions of the by-gone age ([à la the Enlightenment](https://en.wikipedia.org/wiki/Age_of_Enlightenment#Religion)) and there's no reason to think our silly, obviously made-up legends are a reason to kill them because of their even sillier, obviously idiotic legends. Thing is, that's still toleration. Unless you want to reformulate your request, the only possible answer is # There's an uneasy stalemate They both know the other is a blasphemous monstrosity anathema to the Great Aqueous Mother. Some ideas for how this could shake out: * *They just* finished a major war** and everyone's exhausted at the moment (cf. almost any period of peace in human history). The leaders will overlook fairly major provocations just because they don't want to get that ball rolling for a while. * One side already won the war and maintains such a level of superiority that the other has to acknowledge their power, while biding their time and gathering their forces. The Chinese legends about Goujian and his revenge upon Fuchai and the kingdom of Wu would fit this if you like the underdog; the Pax Romana if you like the victor. * Both sides have some hugely destructive threat, such that you've got a threat of mutually assured destruction ([à la the Cold War](https://en.wikipedia.org/wiki/Mutually_assured_destruction)). Hard to imagine what this could be in something as vast as the ocean but, e.g., maybe the fish stocks around the island are the major source of food for both groups but easily destroyed if either side is threatened with extinction. * There's a bigger threat from some third group and they're currently forced to pool their resources (or at least refrain from hostilities) to defend themselves ([à the Greeks](https://en.wikipedia.org/wiki/Greco-Persian_Wars)). * Both sides already lost and are being controlled by some third group, who plays them off each other but prohibits most open violence between them ([à la the British Raj](https://en.wikipedia.org/wiki/British_Raj#Aftermath_of_the_Rebellion_of_1857:_Indian_critiques,_British_response)). * They just don't interact much. The majority of either group is at peace because one lives on the islands and the other lives in the sea. Any time they meet each other, there's the possibility of homicidal rage (à la Oedipus at the crossroads) but it just doesn't happen all that much and they mostly stay out of each other's way, until... [whatever your story is] [Answer] One does not have to approve of all of an individual's actions to tolerate the individual. For example, I might find your politics revolting, and feel physical disgust at the food items you choose to put in your mouth. Your music makes my teeth hurt. But - you are pretty easy going, your personal hygiene is an inspiration to me and when you and I have work to do I can count on you to pull your own weight and make us some money. When there is work, we get along fine. I will just look away when you eat and answer with natural history facts if you try to talk politics. So too your races: the items they disagree upon do not preclude tolerance of individuals and populations of the other kind. [Answer] You might look at how religions interacted in more enlightened periods of our own history - a fair example of this is the way members of other religions lived under Muslim rule in Al Andalus ( among other parts of the world ) where both Christians and Jews were tolerated and accepted, they were allowed to worship and to lead their own lives, but they did have to pay extra taxes. Over time a lot of people converted for tax reasons, but those who didn't were welcome to continue paying extra to live in their own traditions. Most people aren't driven by religious fanaticism, and maybe even those that are can be bought off to a degree if the heretic's taxes are paying for them to have magnificent temples... [Answer] Their religions could ban proselytism: people need to discover the real truth by themselves and trying to force conversion (peacefully or by violence) is a sin. With that, none of your races can kill the other for religious purposes because the heretics aren't evil, just ignorant. [Answer] You do not want Heaven to get cramped. This is another take against proselitism: Those who chose the wrong religion will burn in hell anyway. So we the true believers should not get distracted from adorating our (true) god just to save some heretic's soul; it is their loss! It probably works better with a weak clergy (part time, has to sustain themselves). Because the moment you get people whose way of life depends of being a preacher, it takes very little for (at least some of) them to realize that the more "true believers" there are, the more money for them1 Predestination might be useful: those who are unbelievers are so because god did choose them to burn in Hell, so there is no sense in trying to save them. --- 1Sorry, I did mean "donations to show god their people's faith". [Answer] > > Would it be possible for them to find a way for the majority of people to peacefully coexist? > > > [Laïcité](https://en.wikipedia.org/wiki/La%C3%AFcit%C3%A9) is what we tried to use in modern western world. > > Laïcité ([la.i.si.te]), literally "secularity", is a French concept of secularism. It discourages religious involvement in government affairs, especially religious influence in the determination of state policies; it also forbids government involvement in religious affairs, and especially prohibits government influence in the determination of religion. > > > In its strict and official acceptance, it is the principle of separation of church (or religion) and state. > > > [Answer] ## Redefine Peace Others have mentioned a bunch of ways to hold the 2 sides in check, some of which are nonreligious and/or involve a 3rd group. However, in the long run having the two coexist peacefully in close proximity is extremely difficult. If the 2 races are human-like in behaviour then there will be an extremist fringe who will attempt to purge the heretic(usually in violent ways), preachers who encourage said extremists, unscrupulous statesmen who make use of fanatic sentiment to score points, and so on. Over time they become more and more difficult to hold in check. Without a change in views on religious doctrine the issue will inevitably end up poisoning relations between both groups. Imagine how the Meyra will feel when their town crier tells them that a Cellene nutjob broke into a Meyra family's house and murdered all of them before setting himself on fire when law enforcement arrived. Incidents like that cannot be stopped indefinitely. Therefore you can simply redefine 'peace' as a cold war instead. The leadership of both sides as well as the majority of the public don't hate the other side enough to go to war without the other side doing something provocative first. This makes it imperative for the leaders to keep the extremists from doing something that will give the other side a valid casus belli. Tense coexistence should give plenty of opportunities for political as well as literal knifefighting. [Answer] 1. Balance of terror Both religions are so powerful that an attack on the other religion would be so devastating on both participants and the outcome so unpredictable that both religions refrain from attacking. The situation is even more troublesome if a powerful third party exists who would use the situation to its own advantage. Counterexample how not to do it: [The situation of the Council of Nicaea](https://en.wikipedia.org/wiki/First_Council_of_Nicaea). Christianity split into Roman Catholic, the Arians and Nestorians leading to much infighting. While the beginning of the Dark Ages has many other contributing factors, the struggle for power and the internal schism which culminated later in the [Great Schism](https://en.wikipedia.org/wiki/East%E2%80%93West_Schism) has a definite part that Christianity was much less powerful and the islamic [Umayyad Caliphate](https://en.wikipedia.org/wiki/Umayyad_Caliphate) raised to unprecented power. 2. The other party is just...a little bit misguided This is the position of Islam who claims that the "People of the Book", [Jews, Christians and Zoroastrians are on the right path](https://en.wikipedia.org/wiki/Islam_and_other_religions), but have been entangled in the bushes. So they do not force conversion, but still strive to be the major power and relegate the other religions to observers. The tolerance ends for all other religions: polytheists, atheists and, worse, apostates. 3. Build an interpretation layer between believers and the scripture If you let read people a holy scripture for themselves they could come to unfortunate conclusions, e.g. that differences between religions must be defended by a holy war. So the very best you can do to avoid this is to guarantee that there is "right" interpretation which coincidentally is in accord which suits the leaders. * Be sure that the scripture is written in an obscure, hard to read language. Avoid translations like the pest and claim that the translation is always wrong, only the language by God/prophet/priets is an acceptable choice. * Now you need old, wise men. Those have an impeccable moral record, they have never ever stolen or even told the untruth in their entire life, they were literally born perfect. Those are educated in rhetoric and argumentation so they can perfectly argue that 2+2= 5...erm...4. You must also deny the population to ever get knowledge to argue for themselves, it is dangerous stuff, the mind may explode. So to prevent that someone to ever read, or beware, even interpret the scripture for themselves, always refer to the old,wise man around the corner. This one has studied the scripture for a lifetime, so his interpretation is always correct. * You now also need to handle those unbelievers who might take a look at those scriptures and whom you cannot ostracize. So the old, wise men and their material must tirelessly assure that those unbelievers are a bunch of complete idiots, totally uncapable of independent thought. You cannot trust them one bit. 4. Religion is (currently) less important than other factors. Often religious subgroups who would be persecuted otherwise fill a niche which allows their continued existence. Jews were able to get into the moneylending business because [demanding interest was frowned upon/outlawed for Christians](https://en.wikipedia.org/wiki/Interest) and [other occupations like craftsman were forbidden due to guild laws](https://www.jewishvirtuallibrary.org/guilds-jewish-virtual-library). The [Parsi](https://en.wikipedia.org/wiki/Parsi#Age_of_opportunity), a small religious group of Zoroastrians in India gained enormous influence as contact persons for the British Empire. So you can made a subgroup invaluable because they can do things other religions may not because of prohibition. That does not mean that sometimes persecution set in, like the [Jewish Pogroms during the Middle Ages](https://en.wikipedia.org/wiki/Persecution_of_Jews#Western_and_Christian_antisemitism). [Answer] ## Introduce a more heretical sect Over time, many denominations of a religion can branch out and evolve independently. We could consider the many denominations of Christianity for an example. Time isn't the only factor, but depending on how old your religions are, it may stand to reason your religions already have a spectrum of religious voices / interpretations. From the sound of it, your two religions share some core beliefs. However, if you were to introduce a third sect that both deemed as more heretical, a peace may well be the state of natural equilibrium -- if not an alliance. For real life evidence, consider Shia (including Kurds) and Sunni Muslims in Iraq following the rise of ISIS. Here the most heretical sect was ISIS, which was denounced heavily by many prominent Shia and Sunni clerics. While some Sunni Iraqis identified with ISIS more than the corrupt Shia government, still, in other parts of the country, the case may also be made that cooperation between the sects improved. The premise being that the immediate threat of losing Iraqi territory to ISIS trumped the "heresy" of the rival sect. [Answer] In this answer, I would like to list some anthropological and psychological factors that influence how peaceful people of different religions can coexist. There are objective [needs](https://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs) that must be met in order to survive and thrive. There are also cultural assumptions of how (and how certain) these needs will be met. These assumptions are formed by environment and religion. A worldview of abundance and love for all will be better at promoting peace than a view of scarcity and entitlement. Imitation People tend to imitate their god. Gods [lead by example](http://www.soulcraft.co/essays/lead_by_example.html). > > Well the Meyra, another race, believe that the islands are sinful parts of pure mother ocean along with other Meyra who pure mother ocean believed so foul that they were cast from her embrace. > > > If their god casts out foul people, they will do the same. If their god throws away whole islands and the people on them, they will leave their trash there and treat the people like trash. On the other hand, if their god cares for the islands and the poeple, they will care for them, too. Scarcity or Abundance How do the people view their world? Is it a world of scarcity, or of abundance? Are those islands able to regenerate in a short time? What does their religion teach? Does their god provide for all, the hard-working and the lazy, the good and the bad, the true believers and the heathens? Or are the true believers entitled to take the scarce resources from the heathens, by war, robbery, or additional taxes and duties? Omnipotence or Symbiosis If there are many gods, your god might depend on your help for his own well-being, or to defend against other gods. You will never fully understand why he needs these sacrifices, but they are essential. Otherwise, he might not be able to bless and protect you. A symbiotic god is affected by scarcity himself. He needs you to provide for him. And to fight for him, against the unbelievers. An omnipotent (or at least very potent) god can provide for you in abundance, and he can fight for himself. The unbelievers do not bother him. He will either convert or extinguish them, as he pleases, whenever he wants. It's not your job to fight them. An omnipotent god might even command you to love your enemies and their islands (if he loves them and provides for them, too). Rationalization Man tends to emphasize the features of a religion that suit his needs and plans, and forget about the others--either willfully or by rationalization. This is a factor against peace. Your species might be different. E.g., the Cellene live on the islands, and they get wood, food and lots of other stuff from the islands. When another people arrives and cuts the woods, hunts the game, and leaves a lot of waste, what will the Cellene do? They will defend their islands. They might rationalize that it is their divine duty: > > The Cellene believe that it is there job to care for these islands to the point they give up stuff from themselves > > > And they will always quote this noble reason. But they'd fight anyway, to protect their own livelihood and property. They might even start a war, to protect the other poeple's islands. A god might be more explicit in what he deems good or bad. Or even intervene and remind his people of his commandments. --- Ideas and Sources Edward T. Hall postulates that all areas of a culture are connected to each other. There is a map of culture as a tool for anthropologists (and worldbuilders) at the end of his book "The Silent Language". Kate McCord shows how culture is influenced by religion. In "In the Land of Blue Burqas", she relates how, by meeting a foreign culture and religion, she has learned as much about her own. [Answer] Real world experience shows that religions have a strong trend towards either being violent themselves or inciting violence. The force that keeps them in check in the real world is the Enlightenment and its humanistic values. Interestingly, peace is a humanistic, but not a religious value. So if your religions are embedded in a larger framework that members of all religions agree upon, then you can plausibly have them strife peacefully. If religion is the "top dog" in the value system, the simple fact that you know the truth of the world and your neighbour doesn't gives all kinds of justifications for all kinds of behaviour, and at least some people will use violent means. This is a major piece of history building for your world, as we are not even there in the real world. One more note: The fact that your religions are similar and consider each other heretics instead of just unbelievers is potentially a source for more rather than less violence. People who believe in the wrong gods can potentially be tolerated - ancient Rome had a religious system based on assimilation that worked pretty well, except with Christians who by dogma refused to simply add their god to the official pantheon. But people who believe in the same gods in the wrong way are a potential threat to the religion itself, because they endanger its monopoly of truth. [Answer] Have you considered the possibility of a caste system? In this scenario the different races would follow their own religion and would have very specific places within the broader society. Their settlements on the different islands would help keep the castes separate, and they would definitely be discouraged from intermarrying or mixing religions. They would be allowed to mix for specific reasons (e.g. business) but it would not be common for people to marry or even have close friends from other castes. Individuals would be born into their castes and would remain in these groups for the majority of their lives. In this way the religions can be completely intolerant of each other but would be able to work together when necessary for the functioning of society. [Answer] Omnism All gods are an expression of the same supernatural beings, and while specific teachings and traditions may differ greatly, the underlying supernatural realities of afterlives, vague absolute morality, and possibly creation myths. This is [Omnism](https://en.wikipedia.org/wiki/Omnism), a term describing those who note the commonalities of religions across the world, and decide that the similarities between them must point to a broader truth, even if the specifics get mixed up by we fallible beings. There are probably many religions in this world - as people spread, schisms occur, new gospels are "revealed" to one or another, different traditions lead to new gods, and churches change their doctrine to fit various political necessities. Omnism is first latched onto by those who might describe themselves as "spiritual but not religious" - looking for a non-dogmatic form of religion. There's no official churches, but only the hardcore literalists reject them as heretics - everyone else sees them as largely harmless, if misguided and naive. Over time, as religions drift further apart, more and more "moderates" side with Omnism, until straight-up religion is only held by the strongly traditional. The Cellene and Myera specifically Omnists are also exceedingly good at coming up with compromises. For the island example, they might point to some translation of original texts (or in the case of oral history, an ambiguity of wording) that could be viewed in a less harsh light, and therefore perhaps the islands are not sinful, as the Meyra believe, but actually sacred, and the punishment for setting foot on them is because of despoiling paradise. This changes their attitude towards the Cellene from "hateful" to "compassionate", and they can work together to try to come up with some compromise - such as the Cellene visiting the island fewer and fewer times, until the natural divine order tends to it. But they both agree to keep others away from the island. It doesn't guarantee total peace, it doesn't remove dogmatic literalists, it doesn't remove all the features of religion that lead it to be used for holy violence; but it does give you a roadmap towards religious peace. [Answer] What if the high priests are part of a secret society, with a secret doctrine of universal trancendence of religions? The conflict would be exoterical only, because the leadership would be esoterically linked and could use it's influence to control the zealots. [Answer] Faith is something personal. Each person has to educate his own faith following the old-book and the kinda-new-book-but-still-pretty-old-book. In both religion their is a clear statement: > > "Heretic" are like brother. From an other father or mother. Even if > they don't know who's is real parent are. Even if they call someone > else father because they have been educated by him. They stay your > brother and sister. Every man are made from the same mud. > > > This is enought to rules out every religious violence. Don't do to an other man whats you won't do to your own brother. The other point is more blurry and is about proselitis .The closest translation I came up with is: > > The faith of someone, is it's own. And no one can pretend to someone > else virtue. > > > The interpretation of this is pretty clear, We are all born sinner. And converting an heretic is no gain for your faith balance. It doesn't clear you from your sin. Or give you bonus point. [Answer] Heresy is a wonderful thing, like any other family feud it's worst close to its origin and after that it's mostly just kept going for something to do on a Sunday. This comes down to how religious or enlightened your people are. For something so fundamentally different each covering large parts of the population and each considering the other to be heretical the actual heresy must have occurred some centuries earlier and be lost in the mists of time. * If your people are still highly superstitious, especially as ancient mariner types where the odds of coming back alive aren't exactly great, then this is going to be an important factor and nobody will sail with a member of the wrong religion on board. * If they're more technologically advanced and live less at the mercy of wind and waves then perhaps parents would frown on marrying someone from the wrong church, but otherwise they're fundamentally the same religion. Remember that heresy is abandoning the one true religion. The fact the religions have some common elements doesn't make one heretical to the other, from your description it sounds like they're infidels which is another game entirely, they never were part of the same core religion. This allows them to live entirely in peace as long as they obey the "rules for others" of whichever group is dominant in the region. Those rules are often arbitrary and somewhat oppressive, but also come with certain freedoms including the freedom to be different because they can only apply civil, not religious laws. ]
[Question] [ My story takes place in an isolated community where the people realise the importance of genetic diversity. They will have some problems relating to inbreeding if they don't get fresh genetic material, so it has become a custom for the young women to seek out travellers/outsiders for simple couplings hoping to conceive. The young men of the community consider a new mother who has had a baby this way to be a more desirable partner than a childless/virgin/barren woman. I believe their social conditioning overrules any atavistic disinclination to take care of offspring that are not biologically their own. It has become a rite of passage for a young woman to seek out a sperm donor. Is the above reason given sufficient to justify this as a social custom? Another world building quandary... I had thoughts that a mother with more than one child would be considered even more desirable, although it might be a challenge for young women to become mothers to two or more children in short order. [Answer] ## The Social Rule Alone is Insufficient Social rules are memes (in the original since of the word). They are ideas that spread because they prove some kind of selective fitness for the society that keeps them. Even if the reason for a social rule sometimes falls away to be replaced by tradition/nostalgia, at the time an odd social rule is coined, there should be some equally odd pressure that causes the odd rule to be more selectively fit than the defacto rule. That means that at some point in your people's recent history, there has to be a thing that made copulating with mothers more practical than avoiding it. But this is not easy. In general, mothers are less attractive across most civilizations for 2 very pragmatic reasons: 1. Raising someone else's kid is a lot of work, and people tend to prefer the path of least resistance. 2. Motherhood proves that there is a better chance that another man is around who may decide to protect "his woman" or "his child" making mothers generally less safe to open relations with. This means that mothers will only be the more attractive partners in a society where they offer some safety, assurance, or level of easiness that outweighs the extra risk, uncertainty, and work involved. Don't get me wrong, there will always be outliers in a society who prefer mothers, but for it to become the common preference would require some major outside force that exceeds a random shift in popular views. ## Suggestion: Make Female Sterility Common & Marriage Expensive As a general rule, the more often you come across defective products, the more you care about proving that they are not defective before you buy them. For example, most of the plate armor you see from the Renaissance period has at least one major dent in it... even if the armor never actually saw combat. As firearms got better at penetrating plate armor, it became very important that blacksmiths prove thier armor by shooting it with an actual gun. The tell-tail bullet dent became a mark of evidence showing that the armor was proven to stop bullets which was far more important than any other feature the armor could have. In pretty much any time period other than the Renaissance, you would never consider buying "damaged" armor like that. It was just assumed it could stop what it was designed to stop often enough, but the failure rate of armor had gotten so high that Proofed Armor became more desirable than undamaged armor. Likewise, if you live in a civilization that has strict marriage laws like large dowries, no-divorce, or guarantied alimony from divorces, then marrying a barren woman would feel a lot like getting shot through the armor you paid good money for. Pair that with a high rate of infertility, and suddenly the risk of marrying an unproven women becomes so great that the cost of supporting a single bastard child becomes a minor inconvenience compared to how attractive it would be to know that your wife can have children in a world where that is a rare and desirable thing. [![https://www.pinterest.com/pin/53691420532441693/](https://i.stack.imgur.com/opgZD.png)](https://i.stack.imgur.com/opgZD.png) Also, the reason women would go away to try to get pregnant is also practical because it minimizes the 2nd risk of marrying a mother. When your wife got pregnant from some random passer-by, there is less risk of the man returning and being a threat to you than if it was Chuck from down the street. [Answer] This is a... Dun Dun Dun!!!! Frame Challenge > > The young men of the community consider a new mother who has had a baby this way to be a more desirable partner than a childless/virgin/barren woman. I believe their social conditioning overrules any atavistic disinclination to take care of offspring that are not biologically their own. > > > So, before I answer this question, I am both a Male and a Father - which gives me some authority to speak on this topic. I am also a firm believer that many of our societal norms have a very real biological basis. You may disagree, but that is the position from which this frame challenge comes. Even with very strict Religious and Moral codes to offset the worst of these Biological impulses, Biology still ends up winning. First issue: The average man's primary drive is to have sex with as many child-bearing age women as they possibly can. You might say that this proves your theory. It is my contention it does not. Children, especially small children take up a lot of time, effort and Energy. That means they are not going to have that excess time, effort and energy for the act of procreation. In short, exhausted mothers who have been up at all hours of the night breast feeding and looking after their children don't have the energy to have Sex (and we are presuming everything is consensual here). Second issue: Flowing from the statement about time effort and energy, this is true for the father also (not so much in the infancy years, but definitely later on) - Without wanting to sound like I'm crapping on step-dads (cause I'm not) - the 'reward' of parenting is seeing your kids grow and mature, in seeing the little bits of you be refined and made into a capable young adult. When raising a child that is not biologically yours, that reward is gone. Does that mean people don't Step-Parent, of course not! but even the best Step Parents struggle for the very simple fact that the child is not 'theirs'. Third Issue: Men tend to get possessive over Women of Breeding age. If you look at many of the religious cults that practice polygamy, you'll see multiple instances where all the high-status men (the Elders/Leaders) hoard all the young fertile women to themselves. And Men have the physical ability to enforce their will by being bigger, stronger, more disagreeable and more willing to use violence. So - those are the top 3 issues that I see, and I'm not sure how you can overcome them specifically. However - here are some things to help with your society: 1: If you want men (particularly young men) to do something stupid and against their nature, say it's Manly and make it so doing that thing makes them high-status to women. For example - fighting in a war and dying horribly is (in strict evolutionary terms) very stupid and dying is against most peoples nature. But put a Man in Uniform, with a full rack of medals on his chest and have people call him a Hero - now he's an elligable mate for Women, so his risk is rewarded. 2: Religion has had a long history of enforcing moral codes that would seem to be in opposition to our fundamental nature. I said above that Biology always wins, and I believe that - however just because countries that enforced Monogamy have long, juicy and sordid histories of infidelity, doesn't mean that on the whole the rules didn't have some effect. An enforce Religious aspect could help mitigate the biological impulse - or at least, get you into that wonderful area of story writing where you have tension between two competing ideas. 3: Women set the rules of the Game, Men play to win. Women are the gatekeepers to Sex, Men are the gatekeepers to Relationships. The latter part of that you might have trouble with - because Men will have sex with just about anyone, but getting them to stick around is the hard part - but if you take those presuppositions into account, you might find a series of systems where the Men are incentivized by the Women to do this. [Answer] # There are some problems 1. It would be much more likely that any children born from an outsider coupling would be more desirable, not necessarily the mother who made that coupling. As any subsequent child (with her non-genetically diverse partner) wouldn't have any diversity benefit. 2. If this were the motivation of the society, men would have trouble finding a partner within the community at all. It would be better for them if they went outside their community to find a diverse bride and bring her back. 3. It is more likely that the larger community would support mothers contributing to diversity, rather than relying on any kind of sexual partner to provide support. [Answer] Give the young men a great dread of childless women for fear they will prove barren. Make having children of great importance. Perhaps even have young men told that if they marry a woman who already has a child, they need not fear being childless themselves even if they are sterile. If being a father is important to your status in society, that will also help. The fathers being outsiders will help with suspicion, though expect some misery from women who are barren, and those inept at attracting men, and also wagging tongues claiming that this woman's child was not properly fathered by an outsider but by the boy next door. It might also be considered a duty for the out-child to marry into the adoptive father's family, thus ensuring some benefit for them. [Answer] # Polyarmory and promiscuity makes inbreeding worse Being with multiple people tends to mean more uncertainty over parenthood. This often leads to [worse inbreeding](https://www.bbc.com/future/article/20170726-the-polygamous-town-facing-genetic-disaster) Women who sought out outsiders to sleep with might sleep with the same outsider, so their children would have a tendency to be related. This would notably worsen the inbreeding issue. As such, the social conditioning wouldn't make a lot of sense. # Outside breeding could increase child survival. As such, why not establish an active reason breeding with a native first was bad- suppose their extensive inbreeding depression had a tendency to make babies who didn't quite fit. They tend to be too big, because of large men and small women, and women who breed internally often die of childbirth. Having a baby with an outsider loosens up stuff downstairs, and means that birth can be done safely and reliably. Having two babies with an outsider tends to make things even better. Such outsider babies are seen as good luck charms to counteract infertility, and so are treasured by the families. [Answer] A few things spring to mind: * pregnancy is proof of fertility, which avoids a certain amount of gambling away your best years. * outside genes bring the possibility of stronger, healthier offspring, which is good if you need children to do agricultural work. * first children are not necessarily as healthy or well adjusted as later children, but will be able to help run the household and raise their siblings in due course Its a tricky balancing act to ensure that the child of the outsider is not rejected by their stepfather. The tradition that the first child inherits might be more difficult to apply here if wealth or status is inherited from the (step)father who might prefer his own flesh and blood to inherit, but [ultimogeniture](https://en.wikipedia.org/wiki/Ultimogeniture) is a thing as is [matrilinearity](https://en.wikipedia.org/wiki/Matrilineality). [Answer] It has been so in the past that young widows in Europe had little problems to find a new husband, who could also already have children. This not only because they often had a better financial position than young women but also because they had already proven to be able to reproduce. It has also already been taken up by science fiction writers, I remember a scene from a Robert A Heinlein book, one in the Lazarus Long series, where he had a young couple, girl pregnant, with him while landing on a planet in the early stages of development. The men there would prefer pregnant women or new mothers as wives, for the suspected proof of being able to get more children. If you are writing a strong religion in your book you can attach a religious reasoning. If you write a book mostly based on economics have the single mothers receive a bounty for each child they have before they marry, and have the men of the planet see the economic advantages of the child or children, like having someone to work for them well before their own children are old enough. (New planets/newly claimed lands have children working alongside their parents as a rule, or so you can claim.) And so on, each of your stronger lines in your book can be the reason man want to marry women who already have a child or children. No links for the historic marrying of widows, I have read it somewhere and do not know how widespread it was, I just remember it being mentioned in some book. [Answer] Historically, children are economically valuable. In the modern world, children contribute little or nothing to the households they are part of and a primarily a burden on their parents - they require food and clothing and entertainment and shelter, and their contribution in return is, at most, doing a small amount of chores. This wasn't true in the past. Children would have begun working on the family farm shortly after they learnt to walk, and their contribution continues to grow through life. By the time they're seven or eight, they have positive economic value. The hardest time for a new family then is the time between they start working on their own farmland and the time that they have children able to provide strong economic contributions to that farmland. The reason, then, to prefer women with existing children is that these women come with free workers ready to help support the future children you will make with them. [Answer] Yes, it is perfectly plausible, especially if the community lives in a harsh or otherwise inaccessible environment like a desert or a tundra. In fact I vaguely recall that the Inuit did have a similar custom. But you wouldn't want to make your community too capable militarily, because then it would be easier for them to steal children from surrounding communities instead, which for example the Eurasian steppe nomads did do. [Answer] In Greek mythology, single mothers seem to have had less difficulty marrying if the father was a deity. For example, [Tyndareus](https://en.wikipedia.org/wiki/Tyndareus) doesn't appear to have had a problem with Zeus having fathered some of his children. So maybe in your story the sperm donors are not just random guys, but are perceived as superior. [Answer] So, first we have to remember that genetics is something they may not have a good handle on. Imagine an isolated township, heavily inbred. If there is any fertility issue in their gene pool, they will all have that issue in their genes. That's just how it works in small, inbred communities. Inbreeding and isolation go hand in hand, so it's likely such a group will look askance at young women who consort with the outgroups. On the other hand, fertility issues were nearly always blamed on the woman: it was never his fault, she was barren unless proven otherwise. So that proven fertility...Even with some outsider...That would be a strong draw in a group where infertility was common. We know there is nothing wrong with her, so if we marry her, we'll have kids too. Of course that's fallacious, given that we know that the outcross is fertile, not the inbred choice, but, again, their knowledge of genetics is likely incomplete. [Answer] What if you make the culture such where children are valued? It may be for the same reason -- increase of the work force -- like others mentioned, or something else. But, the cultural consequences I want to point out are * Raising children is a community affair instead of just be the job of the parents * The rank of a woman is directly tied to how many offsprings she has [Answer] ## The children of single mothers are vulnerable to abuse. It's not very nice to think about, but the fact of the matter is that the children of single mothers are vulnerable to being abused by the men in their mother's lives. If you're the sort of man that wants to sexually abuse children, finding a single mother to hook up with is a good place to start, and that would provide an incentive for those sorts of men to choose to target single mothers to form relationships with. [Answer] ## Simpler explanation: they're more mature They've outgrown the primitive desire to "spread one's seed", and don't care much whether their children are biologically related to them. So, if they still want children to love and care for and raise, which many people do, they'll prioritise women with "ready-made" children, to avoid having to go through pregnancy and all that. In the real world, plenty of people date those who already have children, and plenty of people adopt. You don't need some extreme explanation. You just need to lean on the scales a bit if you want it to be more common. ]
[Question] [ > > Count Bobbert of Frugundy has many children, and he has sent his third > son, Preter, to be raised at the court of Duke Wudlig of Brutsels, > both to honour his ally and to allow the child to benefit from the > many scholars and clergymen in the court of Brutsels and receive an > excellent education. But, Wudlig is devious and he knows that the > count's first two sons are sickly. He is counting on this child to > inherit the county, and become his neighbouring ruler. So, Wudlig > subtly sabotages Preter's education. He arranges for noisy military > parades to take place right outside Preter's study room, subtly > encourage immoral behaviour and sins, and makes excuses why no wooden > swords are available for practise today. Ten years later, Preter > returns to his father's court unable to tell a motte from a bailey. > Bobbert is furious but there's no way to tell that it wasn't just > Preter's mental inadequacy all along. Relations between the fiefs > sour, but eventually Preter does inherit and the poorly-ruled county > is duly conquered by Wudlig or his heir. > > > The above paragraph is an illustration - don't take those characters literally or this question would be story-based! Foreign education for nobility was definitely a thing - I see it referenced in a few places but cannot find a source specifically about it. My question is: would a lord sending their child away have reason to fear that they would be raised inadequately due to malice on the receiving lord's part? This doesn't even have to be so overt as sabotage, it could be as little as them doing less than their absolute best to raise their future neighbouring ruler. So an alternative phrasing is: could a lord always count on their neighbours to raise their foreign children the best they can? A third possible phrasing (you can tell I'm having trouble wording this question xD): could a feudal lord under certain circumstances, either overtly or subtly, sabotage the education of a foreign noble heir in their custody, without suffering consequences worse than what they gain by having a weak neighbouring lord? And if so would those circumstances be commonplace enough that the average lord sending their child would have to consider malice? If this is technically possible but only under extreme circumstances (like the recipient living on a remote island) then for general purposes the answer to the question would be no. Assume generic feudal rulers who are not unusually sadistic or unconcerned with self-preservation - just regular people exercising realpolitik. Do not invoke plot-based or otherwise person-specific relations like the two rulers being former lovers; make your answer apply to any two lords that might engage in the medieval student exchange program. Finally, don't assume things about the setting besides the place being divided into feudal realms, and anything unmentioned that is crucial for that setting to make sense (e.g. a class structure, pre-industrial technology). I am not asking this on History.SE so "he can't because the Pope would be angry" is not a valid answer here. [Answer] "Would a lord sending their child away have reason to fear that they would be raised inadequately due to malice on the receiving lord's part?" Let's state the obvious: the question does not specify either a time or a place, and the Middle Ages was both a very long span of time and it covered many different lands. Sending one's son away at a foreign court was not generally a common custom during all that long span of time and in all those many different lands. At most times during the Middle Ages, and in most places, the education of a nobleman happened at home. So let's focus on those times and those lands where it was less uncommon. Let's say, the territory which is nowadays called France around the 10th to the 12th centuries, also known as the Golden Age of Chivalry. In those times and in those places it was indeed usual for young noblemen to be sent to the court of the suzerain of their fathers to be trained as future knights. * First, that would be a particularly stupid (or disinterested) father. One did not normally send their son away at a foreign court unless they had good reason to believe that their sons would be raised well. Was it possible that the suzerain lord was malicious and would deliberately lead the young nobleman astray? Of course it was possible. * Second, it was not some sort of publicly available service. Generally, it was the duty of the suzerain to accept the sons of his vassals at his court. It never worked the other way around, and it never worked between noblemen who did not already have a bond of fealty. Sometimes children went to a foreign court as a matter of necessity, as refugees; but in this case the families must have been related somehow, either by blood or by marriage. In other parts of the world it was quite common for the suzerain lord to demand that the vassals send their sons to his court, as a pledge of fealty; but this was not at all usual in western Europe. Was it possible that the suzerain lord was malicious and would deliberately lead the young nobleman astray? Of course it was possible, but this could easily backfire; one's vassals would certainly take exception and consequently take active measures to switch their allegiance to somebody less traitorous. (That wasn't easy. It was quite complicated, in fact. Great story.) * Third, and most importantly, the education expected to be received by the young heir was definitely not of the kind that noisy military parades would sabotage, and where "scholars and clergymen" played any significant role. The young noblemen joined the foreign court as a page, working his way up the social ladder. He would imbibe the rules of behavior. He would be expected to train as a future knight. Eventually he would progress at the level of a squire. The point being that there was very little in the manner of actual formal study. Reading books was neither expected nor encouraged. The second point being that the young nobleman was working all this time, playing his role in a well-functioning medieval court. He was not a student, he was a fully functional cog in a fully functional machine. The mischievous suzerain lord would need to take great care to insulate the rot instilled into the young nobleman lest it contaminated and corrupted his entire court. Long story short, yes, a malicious lord corrupting the young son of a vassal is possible. Not likely, but possible. And it is entirely dependent on the plot of the story. --- I think that the subtext of this question is a request for resources. I can offer The History of Chivalry, or, Knighthood and Its Times by Charless Mills (1825), available at Archive.org -- [volume 1](https://archive.org/details/historyofchivalr01mill_0), [volume 2](https://archive.org/details/historyofchivalr02mill_0), in particular, chapter 2 in volume 1 is about the education of a knight; also Frank Pierrepont Graves, [History of education during the Middle Ages and the transition to modern times](https://archive.org/details/historyofeducati00gravrich) (1915), with chivalric education covered in chapter 7. [Answer] You influence a child by selecting the right teachers Children do well with a teacher they like and not so well with ones they don't. They can also take on the beliefs of the teacher as well. The Duke selects a likable Buddhist priest to teach morality and ethics which instill pacifism in the child. A fencing master for sword training so the child doesn't learn any real battle combat skills. A pompous arrogant but highly decorated general to teach strategy so they child doesn't listen or try to learn much. By selecting the right teachers you can mold the child into whatever you want without giving the appearance of deliberate sabotage. [Answer] ### No, because children always learnt together Another child would never be put completely on their own, and educated completely on their own. Education of children always happened as a group exercise for all the children of the family together, except for only children. The young prince would then be educated along with the other children of the family. That includes the martial arts, of course - fencing, short-stick (depending on era), archery and riding. As a child of a foreign dignitary, it would be unthinkable for them not to be sent to a family with other children. If Duke Wudlig has no children, then Count Bobbert's son would simply never be sent to Wudlig, ever. Maybe to someone else at Wudlig's court, but not Wudlig himself. Although in all honesty it would be unusual for a child to be sent to live with another family at that kind of age, unless there were family connections. In which case most of the plot doesn't happen anyway. Normally this would happen when they were a bit older, to become a page. ### And education was not what you think it was You're making the standard mistake of thinking of modern schools, or modern tutoring. The world wasn't like that. Once you reached your early teens (or before) you were put into service. So a young man at the court would become a page boy - not a servant in name, and they wouldn't do menial jobs like cleaning, but they'd fetch food and drink for their master, carry messages, ensure the servants had got things ready, and so on. The reason Bobbert would send his child to another court is to learn how that court works, who's important, and how they think; and the same applied domestically for noble families within Wudlig's court. They'd also learn strategy by watching the court whilst they were there. This is the key element of education which you haven't understood about the whole process. As for other continuing education, having learnt the basics as children, they refined it in competition with others. Fencing, archery and hunting were communal activities for the court. Excluding Bobbert's son from the court would be a direct insult to Bobbert himself; Bobbert would remove his son, and diplomatic relations between the two countries would freeze. [Answer] No, this would be unlikely to work. People are not stupid, you do not send a kid to an ally and expect that no one is watching. That never happened. Kids were trained in groups for a start. Also you do not want the neighbouring fiefdom ruled by an incompetent. They will soon be deposed and replaced by someone a lot tougher to deal with that you don't know. So you raise kids to be competent and under your control if possible. It depends on whether it's a friendly alliance or a one sided one in some scenarios I guess. But if it's a relatively equal alliance then no purpose would be served by this that would guarantee a good outcome for you. [Answer] This isn't 'worldbuilding', IMO; it falls under character development, and their motivations and personality. If the character is cunning enough and dishonest enough, then this could be done; it's theoretically possible. The question is: would the person do that? And the answer depends on what sort of person they are. [Answer] Suppose.. this Bobbert of Frugundy would engage a child marriage of his son with daughter Jarcobra of the duke of Barvaria. But in the 5 years following that alliance, his wife would not bear him a second son. That is a great risk ! If anything happens to his only son, the daughter of the Count of Barvaria would inherit his realm. In that case, to prevent Jarcobra from seizing power, he could cut her education, so she will be incompetent to take over affairs. Also, it would make it more difficult for her to get remarried. It didn't happen. Jarcorba became a cunning politician.. causing lots of trouble for Frugundy ! <https://en.wikipedia.org/wiki/Jacqueline,_Countess_of_Hainaut> [Answer] "would a lord sending their child away have reason to fear that they would be raised inadequately due to malice on the receiving lord's part?" Generally, I find that human questions such as this can be manipulated, fine tuned to where they fit reasonably well in the story. What you've explained makes logical sense to me. I have the small amount of historical background on medieval history to know that you are correct about people sending their children to foreign powers for education. But that is not, of course, just a medieval thing. It has been a practice whenever you have nations that are friendly with each other, and one has some center of learning that is considered prestigious. I'll use a modern example of this, using reference from this video: <https://www.youtube.com/watch?v=_jsvmQR19TE> Basically the crux of what I'm taking from the video is where they talk about how some young people in Afghanistan were educated in Soviet Russia, and it had a major effect on the future of the country. You might reflect on why the people of Afghanistan would want people trained there. The devil is in the details as they say - you just need a teeny bit. Something I do know about the medieval period, and really the pre-industrial world, is that people were super, super connected. Everything was about family. It determined who you trusted, who you distrusted, how you rose up in society by whom you married, it would shame your whole family if a family member committed a wrong... So I can see scenarios like "I trust this man, because he aided a widowed relative," or maybe "He has been my business partner abroad and always has shown honesty and tact in his dealings" or "I've read works written by him and I find his views to be quite enlightening." Any of these possibilities, and many more could be enough. A simply mention of it in one sentence, maybe repeated sparsely once or twice, would be enough to keep the reader from considering the character's father foolish. It's also of note that if this is set in a pre-industrial world, it is quite hard to communicate quickly. Letters going "father this dude is pretty sketchy, I caught him trying to set my bed on fire when I woke up" may not get to where they should go - especially with people watching for them. Good luck on your writing friend! ]
[Question] [ I want to make a musical instrument specifically for my dogfolk or other high pitched sound species that can't be heard naturally by humans. I also want to know if is there a way to make a drum that would achieve such sounds? Because I want to include the drums as a musical instrument. Besides I don't know much regarding musical instruments or music in general. The technology and materials range from prehistoric to the modern era, so no futuristic technology, and it's even better if it is achievable before modern technology. [Answer] # Tuning Fork [![enter image description here](https://i.stack.imgur.com/obxR1.png)](https://i.stack.imgur.com/obxR1.png) Okay, it's not a drum, but it is at least a percussive instrument. The higher-pitched ones can be hard to hear for humans unless you touch the handle to your skull or hold the fork very close to your ear, but can definitely be heard by dogs from a greater distance (I speak from first-hand experience on that one). Best yet, they continue to sound for a good while (can last over a minute if you hit hard enough), while other suggestions (microscopic drums) make a sound so short there's almost no point in using them. And a tuning fork is something that already exists and you don't need fancy scientific equipment to make one - just buy one from any music supply store fairly cheap. [Answer] Drums work like speakers, only it's a kinetic impact rather than a magnetic impact that moves the material that moves the air. [![enter image description here](https://i.stack.imgur.com/cuRMI.gif)](https://i.stack.imgur.com/cuRMI.gif) All you need imagine is a drumstick striking the left side of the image rather than the magnetic coil shown in the image. That's how drums work. Several things contribute to this. * The diameter of the drum. The bigger it is, the easier it is to produce low-frequency sound. Conversely, the smaller it is, the easier it is to produce high-frequency sound. * The capacity of the drum head to vibrate. If you think about it, the human ear isn't very good at picking up just one cycle of any sound. The fewer the number of cycles available to hear, the larger the amplitude must be to hear it. > > The healthy, young auditory system can detect tones in quiet with frequencies ranging from approximately 20 to 20000 Hz. Figure 2-2 displays the standardized average thresholds for detecting tonal sounds of different frequencies when the sounds are approximately 500 milliseconds (ms) in duration. ([Source](https://www.ncbi.nlm.nih.gov/books/NBK207834/)) > > > [![enter image description here](https://i.stack.imgur.com/zZ91rm.jpg)](https://i.stack.imgur.com/zZ91rm.jpg) This is why [very large drums](https://www.blueman.com/-/media/bmg/images/shows/highlights/bigdrum.png) must be hit very hard to be easily heard. * Third is the ability of the drum head to relax or return to its original position. The faster this can happen, the higher the frequency can be reproduced. If the drum head requires 0.1 ms to return to its original position, the drum itself cannot produce a frequency higher than 10 KHz. This is easily seen from the perspective of the speaker animation above. If the speaker cone can't return to its first position before the magnet sends the next pulse, the cone simply stays at its extended position and stops making sound. Likewise, the drum would stop making sound (all you'd hear is the sound of the drum stick whacking the drum head - the drum itself wouldn't make sound). It's worth noting that the vibration and relaxation of the drum head are not instantaneous. They slow both in frequency and amplitude. The sound a person hears is not a single frequency, but a series of frequencies in a decaying pattern. The initial strike and the size of the drum create the initial, predominant frequency. It gets quieter and lower from there. This could influence the construction of an ultrasonic drum as the decaying frequency could enter the range of human hearing, although the amplitude may not be high enough for detection. ([Useful Reference, see the part about "shimmer"](https://courses.physics.illinois.edu/phys406/sp2017/Student_Projects/Spring16/Lienne_Pyzik_Physics_406_Final_Report_Sp16.pdf)) What is a drum? Finally, it's worth noting that a drum from the perspective of a musical instrument is something that could be defined as "a musician hits a flexible drum head and the result is a sound not attributable directly to the object used to hit the drum." * A block of wood isn't a drum because what you're hearing is the sound of the drumstick hitting the block of wood, not the sound created by a flexible surface concussing against air. (Musicians don't refer to wood blocks as drums.) * Likewise, concrete isn't a drum because 99% of what you're hearing is the sound of the drumstick itself. * An upturned can is a drum because the metal, though much more ridged than a traditional drum head, is nevertheless concussing the air beneath it. And steel drums are the best example of what might create an ultrasonic sound. But could one be created that dogs, but not humans, could hear? An Ultrasonic Caribbean Steel Drum From [this, which has gotta be the end-all analysis of steel drums](https://www.repository.cam.ac.uk/bitstream/handle/1810/238665/Soren%20E%20Maloney%202010%20PhD%20thesis.pdf), we learn: > > Another implication of using metal alloys for pan production is the effect of the material properties on the acoustics of the note. For instance, if a note were to be modeled as a circular clamped plate, its fundamental frequency can be expressed as [112]: > $$f\_{0,0} = \frac{0.467t}{r^2}\sqrt{\frac{E}{\rho(1-v^2)}}$$ > where t is the thickness of the note metal, r is the radius of the note up to the clamping boundary, $\rho$ is the density of the note metal, E is its Young’s modulus and v is Poisson’s ratio. > > > From page 29 of that document we get the variables filled and, using a steel thickness of 0.55 mm: $$ f\_{0,0} = \frac{1.2696}{r^2}$$ Which, if I've done the math right, gives us a drum head radius of 8mm to achieve a 20 Khz fundamental note. Conclusion The answer is no, you can't make a drum that emits a frequency beyond human hearing. The drum head's manufacture (a material with a quick enough recovery capability) and size (8mm and smaller using stainless steel) are physically too small for a creature of the size you're discussing to predictably hit with a drum stick (which must, itself, be smaller than the diameter of the drum head). [Answer] Yes, it is possible. Drums make sounds because the drum skins vibrate - just as the membrane in a loudspeaker. The faster the skin vibrates, the higher the pitch. It is quite possible to make drums that make ultrasonic sounds (above 20 KHz). [Dog whistles](https://en.wikipedia.org/wiki/Dog_whistle) usually make sound in the 23 to 54 KHz range. Four things affect the pitch of the drum: How big the drum is (smaller gives higher pitch), how tight the skin is (tighter gives higher pitch), the material of the drum skin (steel drums e.g. give higher pitch), and the medium in which sound travels (sounds become more high-pitched in water). The last is probably not relevant here, as I imagine that your dogs are out of water. Ultrasound drums do exist and are used in e.g. medical scanners. [Siemens](https://www.theengineer.co.uk/ultrasound-drum/) makes ultrasound drum heads from silicon wafers each one-seventh the width of a human hair. [University of British Columbia](https://www.nsmedicaldevices.com/news/portable-ultrasound-device/) makes drum heads of polymer resin, the width of a human hair. You will not need this degree of ultrasound to achieve your goal, however. A tiny steel drum with a tight skin should hence be able to provide ultrasonic sounds in the range you need. A problem could be that it is difficult to achieve a very high volume with such a small drum, but then again, dogs have very good hearing. Another problem is that the drum sounds will be very short - more 'plink' than 'boom', as in a steel drum, but even shorter. [Answer] Does it have to be a drum specifically? If you play around with a drum kit, you will notice that the cymbals make different sounds depending on where you hit. Hitting the top of the ride or crash cymbals with the tip of the stick will produce very high pitched sounds, and depending on the cymbals you have these sounds may be at the edge and/or above of the human hearing range. The thing is, even though you cannot hear these, you can feel it. It hurts the ear a bit when it is loud. Remember that dogs pick up sounds from way farther than humans do. If you have a dog at home and it comes when you call it, try calling it by whispering from another room ;) breeds with the most wolf-like ears have the best hearing and can hear you opening the peanut butter jar from across the house. This is all to say that you could strike a special cymbal's top from really far so that no human hears it, but dogs do. --- If you must insist on a drum: again with drumkits, the smaller the drum the higher its pitch. The lowest sounds you get come from the floor tom (the big one usually to the right of the drummer) and the bass drum (the one at the center of the kit, which you play with a pedal). The highest pitched one is the small tom, at the tol of the bass drum and to the center left of the drummer. Make a drum small enough and it will be ultrasonic. If you are close enougg you would hear it being beat - it would be a weak sound though, like the sound a drum with a drum mute or a training pad does. That would be mostly comming from the stick. The drumhead proper would be inaudible for humans. I don't know what size such a drum would have, but it would be really small - way smaller than a tambourine. If you wish to go electronic: drummers who live in apartments and don't want to be evicted usually play electronic kits, or use drum mutes (a kind of muffler) or training pads. You can attach a piezoelectric transducer to these (the electronic kit uses such transducers by design). A transducer is a device that converts some non-electric sognal into an electric one and vice versa. So you could detect vibration on a mostly muted drumhead or pad and have a computer or smartphone play some ultrasonic sound. If you like DIY you can actually do this with a Guitar Hero drumset, a PC and a speaker. I did this once, not to play ultrasonic sounds but regular drumkit ones. I know for a fact that the PS3 and X360 drumkits will be detected by the PC as Plug and Play joysticks (with each drum or cymbal assigned to a different button, which is "pressed" when you hit them) - the Wii one will just detect the wiimote, but some special software makes it behave like the other ones. Then you need some software to translate those button presses into sound. There is plenty of MIDI software around, but I don't know if they do ultrasound. You could always code your own, or have someone else do it for you :) [Answer] what about very low pitched sounds? by my calculations, a 40 inch drum should do nicely. i used mental math using a chart from this link: <https://tune-bot.com/tunebottuningguide.pdf> however, for the drum you need, I have an idea what could be perfect: a piezoelectric speaker. You can have a drum machine with this that produces beats in the sound range that only dogs can hear. [Answer] Dogs can hear as high 47,000 to 65,000 Hz. Adult Humans can hear as high as 20,000 Hertz, although young children can hear higher. You would have to make the drum out of something like copper or aluminum. As they allow vibrate faster therefore allowing the sound to reach a higher Hertz. Small drum would be required because the bigger the drum the lower the speed of vibrated because of speed from edge back to hit point and vice versa. Dogs with pointed ears will be able to hear better than dogs with floppy ears. So you have to base the sound on what type of ear will be needing to hear it the most. Dogs tend to pay more attention to sounds than humans because humans have a thing in their brain that makes it so that they can block out background noise. Although like in people with autism or sensory processing disorder you will see that they cannot block out background noise. So, all the noise sounds at the same level of loudness. So, the sound would not have to go on exceedingly long for them to hear it in theory. So, I would say based on these facts it is very plausible although somewhat difficult unless you have something like an amplifier like a speaker or something like that. Also, humans might be able to hear it if they are really close it. Some humans can hear higher than others.So, like with some clocks to everyone but a small few they are completely silent but to others they have a horribly high-pitched sound that the dog can also hear. That would also have to be considered. [Answer] # Not completely silent in the human audible range, no. The best you can achieve is a grid of very small, millimeter-range steel or aluminum tympani, each with a steel needle in front, all the needles attached to a padded paddle. Instead of the tympani you can adapt @DarrelHoffman's answer and use tuning forks, which would need even simpler technology. Hit the paddle with a drumstick, the needles hit the tympani and get a supersonic fundamental in the tens of kHz range. You need to fiddle with the tympani spacing, but it would work. Problem is, the whole assembly would also inevitably vibrate in the audible range, and have audible harmonics. [Answer] Such a thing was once a product: the [Zenith "Space Command" television remote control](https://en.wikipedia.org/wiki/Zenith_Electronics#Remote_controls). It made ultrasonic pulses by hammering aluminum rods. It wasn't perfectly silent to humans, the hammer made a little click, but it was close. [Answer] One of the earliest ultrasonic transducers -- patented by Polaroid as a rangefinder in their cameras -- is essentially a drum. The front face of the transducer is a sheet of gold foil (the drumhead). Behind it is a metal plate. Placing a voltage (typically 100 to 200 V) between the foil and the plate causes the foil to be attracted or repelled, moving the foil "drumhead", producing an ultrasonic pulse. Any returning ultrasonic sound vibrates the foil. If charge is left on the foil, it acts as a variable capacitor, and the vibrations change the voltage across the device. Thus, the same device acts as transmitter and receiver. Your application only needs to be used as a transmitter. They are still available for purchase today, even though smaller and better transducers are more common. [![ultrasonic sensor](https://i.stack.imgur.com/8n0p1.png)](https://i.stack.imgur.com/8n0p1.png) ]
[Question] [ So I've been inspired by [this](https://worldbuilding.stackexchange.com/q/123534/2053) question to ask what would a medieval war against an airborne hominid (let's call them harpies) be like? Basically most of the assumptions about the meerfolk of the linked question hold to harpies: 1. Technologically primitive 2. Never discovered fire 3. Previously very little violence between races 4. No communication capable between the two. 5. Magic exists but is strongly discouraged in answers and humans are incapable of manipulating it. 6. Harpies, can communicate with one another and will plan. Plus the following: 1. The harpies can land and are capable of running and walking like humans. 2. Harpies cannot swim. 3. Harpies do not have opposible thumbs and have wings instead of arms. However they have clawed feet which they can use to lift things. 4. Harpies do not form homes or nests, but rather rest on tall items on which they can perch and feel safe. 5. Harpies really like to drop rocks on people, poop on people, and claw people during combat. What means would a medieval society have to avoid and retaliate against airborne attacks by the harpies? [Answer] Actually killing these might not be a problem. Crossbows and bows can both shoot them down, and claws are useless against even fabric gambesons, which basically all soldiers had. However, actually winning a war against these would be nearly impossible. They could fly around and avoid troop concentrations, allowing them to bleed the humans dry over time. If you go after them with a force, they will probably just scatter and raid your supply lines, pick off your sentries, and attack areas you left poorly defended until you leave. They could pick off farmers in their fields, who would usually be unarmed and who are usually some distance away from any help. They could mob small groups of soldiers and kill them through concentration of force. They could attack at night, when it would be almost impossible to shoot them, as the only illumination in medieval times was lamps, candles, and (rarely) torches, and fire only lights up a small area while destroying your night vision outside of that area. If they have access to fire, they can make hit and run attack everywhere, setting homes, castles, and fields on fire. The only way for the humans to win would be to destroy all of the harpies' habitat, but this would be hard, as the teams would be harassed constantly while doing this, and weak medieval states would have a hard time mustering the resources to perform large scale projects like this. Even then, total habitat destruction might not defeat the harpies. They could nest in remote areas, on islands, or simply on the ground. Even if that is uncomfortable, it would not necessarily kill them. [Answer] Actually, in this case I'm not sure that the harpies would be a real threat. They have the advantage of flight, but there's also several disadvantages; * They are very fragile, since hollow bones, little mass, * Large wings are a large targets, * They are very light, * They are incapable of flying with much weight, so any armour is out, * Claws are a extremely poor weapon against armored soldiers, * They have no hands or fingers. They cannot easily craft or hold weapons. All things considered, I imagine even a farmer with a pitchfork would be more than a match for a harpy. Humans have the advantage of mass, strength and weaponry. A single harpy would be prey to even a common hunter. Sooner or later, the harpies need to rest, and humans are really good at tracking creatures to their nests and waiting for them. Harpies would only become threats when they gather in large swarms. Imagine a cloud of harpies ravaging the countryside, but even then they would fall to an organised force of armoured bowmen. Overall, I'm not too worried about harpies dropping stones. There's a limit to how much weight they could carry, they won't be able to do it quickly, and dropping rocks is clumsy and avoidable. Any half-decent archer could just shoot them down. The harpies would be well-suited for guerrilla tactics, but quickly every farmers field would start hanging up harpy corpses to dissuade attacks. Harpies would probably be considered scavengers or nuisances rather than serious threats. Methods to fight against them; * Place a standing bounty on every harpy claw. Make sure that every citizen is armed with a bow and arrow to loose whenever a harpy roosts, * Employ teams of professional hunters to hound harpies in the wilderness, constantly thinning their numbers, * Be constantly ready to deploy squads of mounted archers whenever harpies populations get too heavy. * Find out whatever the harpies like to eat, and then hunt that creature to oblivion. * Poisoned traps seem like a good idea. * In fact, is there a disease that affects harpies and not humans? There likely is, somewhere. If so, use it. Perhaps find a bunch of sickly harpies and catapult their diseased flesh over harpy roosts. Methods to defend against harpies; * Have farmers keep their livestock in barns instead of open fields. This is perhaps the most important. Harpies will prey on your sheep and cows, so offer coin to allow farmers to build large, protected barns instead. Maybe they'll invent battery farming by doing so. * Place poisoned spikes onto everything. Literally everything. * If the harpies like to roost onto tall places, then how about glue traps to keep them there? I'm not sure any strong enough adhesive existed in medieval times, but they could maybe develop some. * Restrict the places harpies can hide. Start chopping down all of the trees outside of towns and cities. * Barbed wire aerial walls? * Place a curfew that forbids citizens from leaving populated areas alone. They must travel in groups of three to defend against harpies. * Like any physically disadvantaged predator, the harpies would be prone towards targeting babies and children. Make sure that parents constantly supervise their children - maybe even introduce creche centres to protect the children while their parents are at work. * At some point, harpies presumably need to mate and lay eggs. During that season, the humans declare a mass festival - Egg Smash Month. The humans would struggle to win against the harpies, but they sure could drive them out of human lands. The harpies would likely flock to some mountain peaks to get away. However, this depends on an important question - do the harpies have any aerial weaponry? Can they hold a shooting weapon that can be fired from the air? I doubt that they would be able to reload a bow and arrow with their legs, but perhaps a crossbow that they load on the ground and then shoot in the sky? That could be dangerous. A hail of arrows from two hundred feet would do some damage. Mind, I'd still favour humans to win. If the harpies do have weaponry, they need to have infrastructure to maintain it. If the harpies have an army, they need a mass roosting point to assemble and organise their forces, they need some sort of buildings on the ground to support themselves. That would be the first place the humans would burn. The problems would arise if the harpies start becoming creative too. What happens if the harpies start dropping diseased carcasses into human towns, or poisoning human fields? If the harpies are intelligent enough, the very best way to win a war against them would be to make peace. Come to some armistice agreement, assign separate territories and try to make a long-lasting peace. Hopefully it could be mutually beneficial - the humans could craft tools and shelter for the harpies, the harpies could act as scouts and hunters. In the long run, a war between both races is just going to get nasty. [Answer] A Phalanx armed with spears would be capable of defending and attacking harpy assaults. Archers Bird Shot catapults (lots of little rocks instead of one big one) A ballista or cannon if they are wealthy medieval society. Catapulted nets to ensnare flying opponents. Fireworks (like the ancient Chinese) to burn wings [Answer] Passive defence has historically been preferred over active defence The disadvantages of archers and ballistas is that when under attack: * If it is a surprise you are at a drastic disadvantage in an air attack situation * It must be from a defensible position * A command and control structure must be in place (if it is a surprise, your men will be scattered and communication difficult) * Adequate training and resources is needed to create and maintain such a force - this is very draining against a mobile attack force * The force needs to be where the attack is, keeping in mind your medieval society could cover a lot of ground Historically people tend to prefer passive defence structures especially as you do not know when or where an attack may occur. If a constant threat of an attack is from the sky, I would expect reasonable medieval people to do the following: * Have an early warning system, a network of lookout towers or a way in which enemy movements can be monitored, and communication of that information to decision makers * Live underground, in caves, in rocky outcrops or the side of valleys which have concentrated points of attack which you can control more readily * If you cannot control your entry point, you make it. Such as if you are in a forest, you erect nets over your villages and around them to have only a couple of entry points to control * The ability to, when mobile or in a surprise attack, retreat to a defensible position, such as underground covered trenches, which the enemy cannot enter or manipulate (without opposing digits, it makes it hard to open locks and doors) * Keep in mind your economically sensitive and reliant areas need also protection as the war drags on, such as trade, crops and livestock. For these areas I would expect a roaming active defence, such as small mobile (horseback) forces, or numerous towers and ranged weapons - but at this point you would steadily lose the war without dealing with the source of the problem. As is always the case in conflict, the source needs to be addressed. If it is territorial, perhaps it is best to not encroach on their territory, or provide them with another. If it is a clash of population, and an outbreak of harpies, perhaps an analysis of where they get their food, and affecting their food supplies and therefore resources, and where they nest. [Answer] a scorpio was a piece of Roman technology that worked like a large man sized crossbow. they could probably be adapted to fire nets or some kind of projectile. when shooting birds hunters use a kind of ammo called bird shot which is a casing full of small pellets that spread out after firing giving a higher chance of hitting a fast moving target. maybe some kind of crossbow/catapult/balista adapted to fire a medieval equivalent. smoke screens would also limit the harpies ability to flyou as they wouldn't be able to see where they're going or possibly even suffocate them. [Answer] ## Horse archers All those answer about bows and ballista assume that harpies have bird-like intelligence. If they have near-human intelligence and are just descent flyers, they would drop their rocks from 1000m high. Inefficient but totally safe. But most likely those half humanoid creatures are poor flyers. After any attack, just chase them down until they have to take a rest. A horse can follow a slow flying bird and a competent bowman would easily hit a large creature resting on top a a tree. If your city is surrounded by high cliffs, that’s though luck. But otherwise, you can trim the landscape near your cities to forbid any safe landing. Build guard towers on the hills, spike on top of a lone pike etc… Even better if you have garrisoned horse archers in guard towers surrounding the territory. You could easily force the harpie to fly 50km before they can land. Real bird can do that. But not even all of them. [Answer] Humans are going to win due to superior intelligence unless there are TONS of harpies - enough to just constantly buzz around and no matter how many you kill, more keep coming. Let's assume very deadly harpies: they are smart enough to be dropping fist-sized rocks from 1km high and can fly for 1000 km at constant 20m/s flying speed. So, you can't catch them, can't shoot at them, can't anything, and they are fast enough to hunt and run. Yet, I believe humans would adapt even to such insane threat. Not all settlements can be saved. Fields would be ravaged and no food = dead humans. But even such crazy harpies in sizeable numbers wouldn't be able to stop people living near sea, where these rocks would be unable to stop fishing and gathering seafood. Add thick roof against these rocks and enough archers + pikes, and harpies cannot do much damage. Medieval humans would be never able to completely win and eradicate the threat - there is just too much ground to cover at 1k km harpy range - but people would be able to live semi-reasonable life and sooner or later discover weapons with long enough range to reach these harpies. Then farming and whatnot becomes possible too. Obviously, weaker 100 km range, 100m high, 10m/s harpies would be easy enough to counter with medieval tech too. Put guard towers far enough to deploy archers + whatnot to protect fields. Use horse archers to hunt these harpies back to their homes. [Answer] Train harpies to kill 'wild' harpies. You say that 'no communication possible between the two [harpies and humans]', but it doesn't take much to give simple commands. Catch a harpy in a net, cage it, and start rudimentary training, starting with making sure it understands that obedience equals food. Treat it like a smart animal. It'll get the principle quickly. Then train it to kill other harpies. If you've trained it well, it'll perform for you. You'll make good equipment for it, so it'll have a one on one edge. Once you've gone through trial and error, and maybe a number of failed harpy training attempts, you'll be able to expand your program. Sell your trained harpies to farmers, to help them with harpy defense. Pretty soon, every farm in the kingdom is going to have one, and the wild harpies will have trouble finding food sources. Don't worry hunting down the wild harpies to extinction yourself--this would ruin your business. [Answer] I agree with Madlozoz. A war with harpies implies they're intelligent. Elsewise, they'd just be a nuisance, like hawks or airborne wolves, not an organized menace. What's more, without intelligence, why would they attack humans? Sheep or cattle would be far easier targets if they just needed food. I also don't think humans would have a decisive advantage overall. In full-out combat, soldiers would probably be more effective. Like Madlozoz said, though, flyers could drop rocks, and even small rocks could be devastating if dropped from high enough. If you look at their civilizations, humans would likely have more resources (farms, castles, etc), but would also have much more vulnerable infrastructure. Flyers could easily drop burning material onto crop fields or villages or dead animals into wells, or scatter livestock and hamper farmers during critical points in the growing season, and humans are very dependant on reliable food production. They could also attack territories far faster than marching soldiers could meet them. Plus, the terror factor of being able to drop out of nowhere would make them hell on the local population. On the other hand, as has been mentioned, flyers would probably be weak and awkward on land, and so would likely have difficulty developing mines or farms. They would probably be more of a hunter gatherer society. If so, their resources would be primitive, but they wouldn't have much to defend either, especially since they would probably prefer to live in areas humans found hard to access, such as cliffs or caves, making them hard to really attack. So in the end, I think humans would have the upper hand overall, but they'd still have a hell of a time defending their territory, much less winning a decisive war. ]
[Question] [ Context: It is set 50 000 years from "now" in no-FTL interstellar setting. The idea is that active defences and armor of spacecrafts have obscenely advanced to the point that any projectile has to get on the collision course both quickly enough to not get obliterated on it's way and reach at least dozens of terajoules of kinetic energy to have a chance to get through. This is the official reasoning for the dominant tactic being fleets of billion ton spacecrafts meeting in short 50+ km/s fly-bys and exchanging rapid close range fire of relativistic (1% - 10% of light speed) projectiles, while being protected by 30+ metres of armor of unspecified composition. So, the question is what kind of engines and maneuvering thrusters could survive this? Even though rule-of-cool definitely plays an important role here, and the 50 000 years of technological advancement is very good at plugging most holes, I'm still trying to keep to real physics, or at least not stray away from it too much, which means I'm very hesitant to just handwave it with some sci-fi magic or technobabble. Options like chemical, fission, fusion and definitely antimatter propulsion don't seem like things that would do well once someone starts shooting up their exhaust. I have been thinking of Orion drive maneuvering thrusters, in this case it could just be a re-purposed coilgun for the nuclear shaped charge and a well shaped piece of what is already it's standard armor, but while a bit more durable, I don't really trust the reliability of this given that debris from "shot down" projectiles and fragmented armor will be flying all around the place and could destroy the nuke used for the drive or knock it off course. Orion drive: <https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)> So the end goal is allowing these ships to reliably maneuver in the conditions described above, for example it has to at least survive an impact of a cloud of debris (up to 5 mm) moving at 10% of light speed (edited: previous requirement was surviving a solid 50 terajoule projectile) while turned on and moving the ship, and such debris impact should not keep it from continuing to do so. At the same time it must be based on known physics, nothing highly speculative. (Also please be patient with any grammar issues, I'm not a native English speaker) [Answer] Sometimes the simplest answer is the best. If you don't need to worry too much about mass, just have the main power plant buried deep in the body of the ship with a lot of redundant nozzles. In battle shutter or otherwise shield your primary thruster (you're going to be maneuvering mostly) and using an array of smaller redundant thrusters. If they're damaged beyond repair? Jetsetton them All that tubing also essentially acts as spaced armour. I'd even go as far as suggesting integrating the nozzles used into the armour as an outer layer away from the main ship, like slat armour or that can be replaced as entire units. Think those cubes in cubes machinists do to show off. [Answer] You have giant, heavy battleships doing very short flybys of each other at relativistic speeds with very short engagement times, evasion will be pretty much not a thing. So just cover up any exhausts or engines with movable armor plates before entering into close combat and become a flying brick. [Answer] [Reactionless drive](https://en.wikipedia.org/wiki/Reactionless_drive) is one option: "A reactionless drive is a hypothetical device producing motion without the exhaust of a propellant." Because there is no need for exhaust, the drive can be positioned anywhere, and armored heavily from every side. There is already [one potential reactionless drive about to be tested](https://interestingengineering.com/innovation/quantum-drive-that-draws-limitless-power-from-sun-will-fly-to-orbit-this-year). [Answer] # Tiny holes and long shafts - ion engines The amount of time in the future gives some leniency. You can then opt for a certain form of ion or plasma engine, even if it might operate differently at such times. The idea is simple. If you throw something away from you, you'll get an equal thrust the other way. The harder you throw, the more energy is also used to propel you away. Ion engines use this concept for 'efficient engines'. You simply throw miniscule particles as hard as you can in the opposite direction you want to go. Using methods that generate/contain more energy than chemical bonds you have ample energy in small packages, with a small resource to fire away. You can pair the insane power of nuclear (fusion) with a cloud of gas you can fire away. This setup allows for long shafts for the exhaust, with small openings in several directions for the direction. To make things more complicated but feasible on such large spaceships you can have (a) particle accelerator ring(s). In these rings the particles are accelerated, adding more and more energy, to eventually be released through the right exhaust tubes for thrust. In current circumstances this wouldn't work. Any form of ion thruster is incredibly weak. They can accelerate spaceships over time to great speeds better than any other methods, but would be unfeasible for any maneuvering of battle spaceships. Not to mention that it is very hard to control particles exiting a particle accelerator ring at the right time. This heavily relies on the technological advances in your story, allowing enough thrust and accuracy to do so. As it isn't sure this would work, it will only loosely be based on something that is used in real life. ## The result Your exhausts are protected by being small and numerous, allowing for acceleration into any direction, redundancy of exhaust ports, as well as being closed when not firing at that time. Even if they are open, the exhaust tunnels are long enough that it's difficult to damage anything important, let alone the particle accelerator ring 'engine'. You could also argue that any debris that might block it can be burned away thanks to the particles in many cases, allowing the exhausts to unblock themselves during a battle if the damage isn't too great. If I can paint a visual picture, instead of huge engine exhausts you can have sleek ships. Their hull seemingly one piece until it is required to move in the opposite direction. Many tiny holes open up, showing small flames of thrust. Not that ion engines would produce that effect, but the rule of cool allows it. From a distance it could give a certain colour to a part of the ship as it moves and manoeuvres, as well as give a plausible way to move in literally any direction or maneuver in any way. [Answer] # Well timed nukes They use orion drives, dropping nukes behind them which will explode and push them in a particular direction. The nuke tube opens for a fraction of a second, releases the nuke, and closes, so enemies can't fire on them. [Answer] You leave them outside of the battlespace. By detaching them after you are up to speed, sending them in a parallel trajector to the combat-run. After traversing the battlesphere, the two reunite for the deacceleration and go-around push. If the combat capsule does not survive the engagement, the engine either returns to base or goes on a suicide mission. The capsule has all the weapons, small "jump" thrusters and gyroscopes to change direction fast. [Answer] ## The drives are made mostly of magnetic field and are empty. Your space ships are propelled by large magnetic confinement fusion drives. Their chambers and nozzles both are made of magnetic fields since no regular matter can contain nuclear fusion plasma anyways. In space there is no need to contain vacuum, so no hull is needed. Of course the drive needs fuel injection system, sensors and magnetic coils (however a significant portion of magnetic field is created by the plasma vortex itself). But those systems are: 1. mounted on a grid frame around the engine 2. relatively small and hard to hit while most incoming projectiles will simply fly trough the contained plasma into the space. 3. made redundant and replaceable. The engines handwaved in a such way may even be considered the most durable part of the ship. [Answer] Throwing it out as an option not necessarily a recommendation. As far as RCS or directional thrust protection.....Don't... Just assume anything outside of the armor and shielding is going to get fried. Pitch roll and yaw can be induced with flywheels/gyroes, then just use your main thrust for any course correction. Of course this is for battle conditions. Perhaps another configuration / method of maneuvering can be implemented while under normal operation. [Answer] ## Frame Challenge: Armor does not lead to bigger ships There is a logical issue in your assumption that better armor leads to bigger ships. In fact, better armor should lead to smaller ships because of the linear-cube law. As you increase the size of a ship, the effectiveness of armor goes down very quickly. Think of it like this. Imaging you have a ship that is 10m long and has 1cm of armor; so, you decided to make a bigger ship with thicker armor. To do this you need to make everything bigger. Bigger engines to push the added weight, bigger power sources for your bigger engines, bigger crew spaces for the added maintenance needs... so when all is said in done, you scale the whole thing up and now it is 100m long with 10cm thick armor. But here is the thing: in order to make your armor 10x as thick, you've increased the size, mass, and cost of your ship to be 1000x as much as the smaller ship. This is because the science of armor penetration is all about focusing your energy into as small of a cross section as possible; so, when your 100m long ship gets hit by a shell that is only 10cm wide, only 2e-7% of your actual armor gets to do anything about trying to stop the shot whereas the 10m ship is contributing 2e-4% of its armor to block the same attack. This relationship of size to armor is why we still have armored tanks and attack helicopters, but not large armored naval ships. ## Focus on active defense like shields and point-defense weapons If a 10m ship has a shield that can block a 1e15J of total energy before draining it's power supply, then you must overcome 100% of the ship's shield before you can harm it. So, if you scale this ship up to 100m, then you can block 1e18J before taking damage. This creates a linear relationship between a ship's size/mass/cost and its defensibility. Furthermore, by blocking all damage until the shield fails means that even a slightly smaller ship is at a big tactical disadvantage encouraging the constant development of larger and larger ships. Likewise, if a 10m ship has enough interceptor missiles to shoot down 4 torpedoes, then a 100m ships can carry enough to shoot down 64 torpedoes using the same % of its allotted mass. Active defense also means that there is no practical difference between getting targeted in the engine vs anywhere else on the ship because all hits are blocked until the defense fails. Since it sounds like your setting already makes use of active defense, you should focus on these, because these will encourage bigger ships in a way that armor can not. ## Soak hits using redundancy instead of armor Maybe you don't want active defenses to be 100% effective. Instead of making your ships armored, make them able to afford more hull hits. One advantage of a bigger ship is that it's much harder to design a weapon that can damage the whole thing; so, use that to your advantage. Instead of turning your ships into solid bricks of heavy armor with systems jammed in as tightly together as possible to make them all fit behind the armor, make them big, low density, and highly redundant so that when they do take a hit, the attacker over-pernitrates and only destroys a small portion of the ship, and any systems that are knocked out have 10 backups else where in the ship to keep it going. So making it [mesh like](https://static.wikia.nocookie.net/memoryalpha/images/e/e4/Borg_cube_orbits_Earth%2C_remastered.jpg/revision/latest?cb=20130424025909&path-prefix=en), [spindly](https://startrekfleetcommand.scopely.com/wp-content/uploads/sites/5/2020/02/Vidar-1200x648.png), or [mostly hollow](https://www.pinterest.ie/pin/5840674491551210/) will increase the number of hits it can survive whereas armor increases how strong of a hit it takes, but will reduce the number of shots it will survive. [![enter image description here](https://i.stack.imgur.com/GzTTo.png)](https://i.stack.imgur.com/GzTTo.png) ## Your splash-back will be plasma and radiation, not debris With the energy levels of impacts you are talking about, there will not be 5mm debris flying back at you. Any debris that absorbed little enough energy to remain solid will not have enough momentum to reach you before you are well out of harms way. Instead the only parts of tour target you need to be worried about are those that are turned into a cloud of plasma and radiation. Because you are dealing with such long distances, the plasma and radiation with spread out a LOT by the time it reaches you making them barely more dense than conditions you could normally encounter in space. It would be more like flying through a solar flare than what you think of as a debris field. [Answer] This seems like a non issue, if your engines are electric. To figure out how much electricity an engine uses to accelerate a spacecraft, you can use this formula I = (m\a) / (V\E) and the symbols represent the following: I - current (amperes) m - mass of ship (kg) a - acceleration of ship V - voltage of power (i'm using 11kV as my example power) E - efficiency of engines (as a percent, between 0 and 1) plugging this in for a 1,000,000,000 ton ship @ 11.4 KV and 1 m/s2 of acceleration and 100% efficient, we get an electrical current of 82.47MA,that's Mega-Amps. using ampere's law, we can calculate the magnetic field using B = uNI/L B - Strength of magnetic field (tesla) u - Permeability of free space N - number of complete loops are made around the thrust axis I - current (amps) L - length of engine bay. Plugging in a 500 meter long engine bay, and 1000 turns (depending on your setting you may need way more or way less), and assuming the bay is mostly empty space (permeability close to 1), this gives us 200 Tesla. this is about the strength of 130 MRI machines, or about [2 Helmholtz coils](https://www.youtube.com/watch?v=g0amdIcZt5I). with a bit of engineering, one can reasonably push the magnetic field to the outside of the engines where the effect seen in the video (the loss of kenetic energy in conductive objects) will stop debris. of course, you can tweak all of these numbers to suit your needs. maybe 1 m/s2 isn't quick enough, or there are less coils in the engine bay, but the fact remains that magnetic fields are incredibly useful at stopping metallic debris such as meteors and certain projectiles. The weakness of such a system is that the magnetic field is only active while the engines are on, and so for an engine to be off is for an engine to be unshielded. Hopefully this is a good foundation to work off of in your writings! ]
[Question] [ I've been working on designs for some model starships, in particular warships. My working assumption has been that the designs and materials for these ships will reflect the way that the civilisation itself conducts warfare. Purely as an example: a warship that uses particle beam weapons will be shaped and armoured to maximise its survival under fire from similar weapons. This is predicated on the assumption that said vessels are being designed and built by a civilisation that has never actually gone to war with any external military force, they have fought at least one internal conflict include space warfare or they'd have no militarised spacecraft at all. I'm wondering if that assumption is valid. My question is what, if any, factors/events (aside from contact with another civilisation that uses different tactics and/or weapons) would lead to a military force building ships that use armour and/or hull shapes designed to defend against weapon systems that that force does not itself use? Assume: * the civilisation has met no alien beings. * they think their primary weapon systems are the best available option (they could be wrong). * other weapons have never been seen as viable options for primary combat operations. * fitting out different or multipurpose armour/hull designs is relatively expensive. [Answer] > > My question is what, if any, factors/events (aside from contact with > another civilisation that uses different tactics and/or weapons) would > lead to a military force building ships that use armour and/or hull > shapes designed to defend against weapon systems that that force does > not itself use? > > > # Events That Trigger Innovation *Small, Far Away Conflicts Involving Others* In times of relative peace, very small scale conflicts far away and accidents that illustrate graphically military vulnerabilities can have a profound impact. The fundamentals of trench warfare tactics, for example, were invented in New Zealand in what are now called the [New Zealand Wars](https://en.wikipedia.org/wiki/New_Zealand_Wars): > > The New Zealand Wars were a series of armed conflicts that took place > in New Zealand from 1845 to 1872 between the Colonial government and > allied Māori on one side and Māori and Māori-allied settlers on the > other. They were previously commonly referred to as the Land Wars or > the Māori Wars, while Māori language names for the conflicts included > Ngā pakanga o Aotearoa ("the great New Zealand wars") and Te riri > Pākehā ("the white man's anger"). > > > This conflict happened, literally, half a world away from Europe between factions utterly unfamiliar to most Europeans, and was on a tiny scale compared to WWI that would follow, but a few cutting edge military planners studied the tactics used then and those tactics soon became dominant in WWI in short order. Similarly, the [Falklands War](https://www.globalsecurity.org/military/world/war/malvinas.htm), even though it occurred at the opposite end of the Earth from England, didn't last all that long and resulted in only 1000 deaths, did more to influence warship design and naval strategy, and the logistics of power projection, than any other post-WWII conflict. Most importantly, it illustrated the immense advantage that a single skilled submarine outfitted for war could have over a substantial fleet of surface ships. At even smaller scale, civilian troublemakers who have targeted commercial aircraft with high powered laser pointers that could be used to blind pilots eyes have led to countermeasures against this threat in military aircraft even though this kind of attack on pilot sight has never actually been used in warfare. *Accidents And Natural Threats That Present Obvious Military Lessons* But, not all of the events that lead to radical innovation are actual conflicts. The Hindenburg disaster brought the use of hydrogen inflated airships in war to an end before it had even begun (even though the flammable material used for the sheath rather than the inflating gas was the main issue in reality). The Titanic's collision with an iceberg led to a radical rethinking of the importance of adequate lifeboats and evacuation procedures for sinking ships that influenced civilian and naval ships alike and also commercial and military aircraft design precautions for water landings that followed. Accidental collisions of U.S. Naval ships with civilian ships in peacetime have led to major changes in how crews are prepared for readiness. Civilian commercial aircraft accidents have led to numerous innovations in how military aircraft operations are run and how military aircraft are designed. In a space setting, deadly accidents, for example, from impacts with space debris or inattention of safety issues with solid rocket boosters, would alert planners to the same kind of potential risks. As another space example, the fear that an asteroid or comet impact could caused massive harm to Earth as it has multiple times in the past could lead to the development of anti-ET object technologies with obvious military applications to new threats. # Motives That Trigger Innovation > > what, if anything, would make taking measures "worth the effort" > before you meet an organised military force > > > Necessity is the mother of invention and efforts to anticipate new military threats usually involve a perception that there will be a near term need to use military force. But, it is also important to recognize that this motive need not e widespread. It only needs to e widely shared among political and military decision makers who have considerable personal power. *A Strong Inclination Of Leaders To Use Military Force To Achieve Political Ends* Lots of the historical examples involve the sponsorship of military innovators by political leaders who anticipate being the aggressors to conquer previously insurmountable barriers to military success, or at least, are not so much pro-military as pro-use of military force (two very different things). For example, the Third Reich invested in military innovation that revolutionized modern warfare, because they planned on using it well in advance, and at first in WWII, it gave them an edge. Far earlier, the Hittites did something similar, developing innovative metallurgy techniques for their weapons and coming up with chariot warfare tactics, because they planned on conquering as much of Anatolia, Mesopotamia and the Levant as they could, while their opponents only started to innovate once the fighting began. Military innovation by non-aggressors in the WWI, and WWII didn't have top leadership support and financial support until those wars were in progress. Neither side innovated much before combat began militarily before the U.S. Civil War because most people on both sides didn't think it would happen with any vigor. Vietnam was another war that was unanticipated for U.S. forces leading to military innovation only once the war began. *Widespread Anticipation Of Isolation In Foreseeable Future Conflicts* On the defensive side, military innovation is frequently triggered by a perception of a clear and present dangers that the defending military can't count on anyone else's help to protect them from. After Hiroshima made the threat of nuclear weapon a widely anticipated one, both the U.S. and its allies and the U.S.S.R. and its allies innovated in earnest prepping for a widely anticipated nuclear war that never was. Some of the countries that have contended "far about their weight class" so to speak in terms of military innovation have been Israel, which has faced ongoing rhetoric from its neighbors who say they want to drive it into the sea; South Africa, which lacked international allies during apartheid and also had good reason to fear an insurgency; Iran which has spent much of its recent history diplomatically isolated, with vocal threats from the U.S. and Saudi Arabia, and Switzerland, which has built a foreign policy around self-reliance and neutrality achieved by not entering into alliances. What did this lead to? Israel basically invented the anti-missile missile, invented military concepts that include large numbers of women as soldiers, devised several new kinds of anti-terrorism tactics, and did more to develop the art of the air to air fighter battle than any other country since WWII. South Africa invented what the U.S. called when it adopted them for use in Iraq and Afghanistan, the MRAP (mine resistant, ambush protected vehicle), as it prepared for counterinsurgency fights that it anticipated. Iran pretty much invented the concept of the small, fast, coastal, heavily armed, lightly crewed missile boat, and the widespread use of non-nuclear coastal submarines to effectively threaten much more powerful military surface warships. Switzerland has developed dozens of defensive military systems and strategies found nowhere else in the world, with one of the world's largest citizen's militias, large underground bunkers with caches of weapons and supplies and room to evacuate citizens too, bicycle based anti-tank weapons, and all manner of other response to the threat of an invasion of its country with conventional military forces. The tangible fear of conflicts that were widely anticipated and very specific led to innovations that countries with less clarity of mission and more promises of military support from allies did not. # Other Factors *Small, Non-Meritocratic, Non-Bureaucratic Political Organizations* > > If you're not actually fighting wars, you design your weapons systems > to protect against the most dangerous stuff you can think of. This is > what the US Navy has been doing for the last 80 years. > > > Not really. If you're not actually fighting wars, the norm is that you design your weapons systems to win the last war that you fought, whether or not it makes sense to do so. The U.S. Navy is a prime example. Only modest steps have been taken to respond to multiple post-WWII threats, and the predominant ship designs date to the 1980s, about 35 years ago. There have been minor upgrades but not major rethinking. There is a sociological reason why this happens. The people who are promoted to make decisions going forward are the people who were most successful in the last war, whether or not those traits are valuable going forward, because people promote folks who are successful rather than people who weren't. But, the people who were most successful in the last war are the ones who are most wedded to old technologies and tactics. For example, in WWI millions of lives were lost when generals insisted on using cavalry charge tactics long after it became clear that the machine gun had made them obsolete. In contrast, the U.S. Army has fought many wars since WWII and has radically remade itself as a result in response to what has and has not worked in recent conflicts, for example, replacing the heavy tracked tanks designed with WWII in mind, with lighter, air transportable wheeled vehicles, which in turn were supplanted by vehicles adapted to IEDs and ambushes with armor piercing bullets. Meanwhile, anti-aircraft guns and artillery that were prominent in WWII faded as the U.S. Army always had air superiority and as cruise missiles and aircraft based smart bombs made howitzers obsolete. Also, in the absence of actual experience (personal or merely observed in others) with asymmetric warfare, military tech procurement planners unconstrained by the hard reality of actual war often fall into the mental trap of planning for "fair fights" against similar systems. Tanks designers dream of tank v. tank wars, even thought tanks were invented as anti-infantry weapons. War ship designers dream of blue sea surface combatant duels, even though submarines, aircraft, mines and hypersonic missiles are the real threats. War plane designers dream of dog fights, even though one shot, one kill before the enemy knows you're there has been the leading approach in actual air warfare since Vietnam. Enlightened military leadership is rare and usually comes down to a handful of innovators who are ignored and derided until they somehow secure power. In these situations, overcoming the natural sociological and organizational instincts to fight the last war, and to prepare for "fair fights" with weapons facing off against opponents with similar weapons, you need to have some mechanism, almost a corrupt one, that overrides conventional uninspired bureaucratic conceptions of meritocracy. Basically, the happens when some rare military innovator has a power base or political patron who can overcome the natural inclinations of a military bureaucracy. Outside of times of actual war, this is something more prone to happen in a monarchy where people are promoted for reasons other than perceived talent, than in a democracy or any other technocratic state. For example, a powerful crown prince in a not very large country may have more of an ability to throw is support to a maverick military innovator than a senior civil servant or high ranking soldier in a large technocratically run, not particularly corrupt, highly bureaucratic military force. It is more prone to happen when power is securely concentrated in a small number of key political leaders than when it is dispersed which requires more collective action to overcome barriers to innovation. It is more prone to happen in countries with smaller military forces than it is with larger once, since bureaucratic inertia isn't as great and there are fewer senior official who must be won over to secure change, subject to the caveat that certain kinds of innovations are possible only with the huge military budgets only available to the largest and most economically powerful countries. For example, military innovation in the early modern period was greater in independent micro-states with hereditary leaders in what became Germany and Northern Italy prior to the late 1800s, than it was in countries that had been large for a long time like France and England. *Innovation In Other Fields* Another way that military innovation against previous unanticipated threats can develop is as a side effect of health non-military innovation. For example, a large civilian economy driven revolution in computers and electronic communications from about 1960 to the present, has given rise to technologies that have been easy to adapt to military ends once developed. These technologies also often trivially imply the need for new kinds of defenses (like cyber warfare defenses that evolved to a great extent out of criminal and accidental breaches of security in civilian systems). The development of a standardized modern rifle in the 19th century (and innovations like the machine gun that this made possible) was largely a product of manufacturing technologies developed in the civilian sector that made it possible to mass produce goods made of interchangeable parts. Going back much further, the naval superiority of the British, Spanish and Dutch fleets largely derived from innovations in ship building technologies developed initially for commercial applications. A generally prosperous economy driven by civilian innovation also makes it much easier to raise tax funds that make it easier for politicians to budget for guns instead of butter, decisions which can free up the funds needed to finance expensive military innovations. [Answer] I'm going to present a frame challenge here because there are a couple of really important factors that your question leads me to believe aren't getting proper consideration. First: The biggest reality check that almost everybody ignores when it comes to spacecraft design is that NOTHING is more important than mass. Earth-based vehicles of all types can make use of the ground, the water, or the air to help dissipate or otherwise support the mass of the vehicle and help propel it more efficiently. Spacecraft can't do that. So unless you're planning to handwave Newton's third law away by positing propulsion systems with effectively limitless thrust and fuel, then the most critical aspect of your design is making the spacecraft as mass-efficient as possible and that means no heavy armor. Warships in The Expanse universe are a good example of this. This is more near-future than most science fiction shows, and even the biggest warships are only armored well enough to protect against shrapnel, because any armor that could actually stop a direct hit from a projectile would make the ship so heavy that it couldn't get anywhere you needed it to go in the time you have to get it there. If you're actually concerned about realism, the defenses on your warships will be electromagnetic in nature, either star trek/star wars style shields, or more realistically: electronic warfare designed to prevent your opponents from being able to target you accurately enough to hit you in the first place. Second: Military designers are RUTHLESS pragmatists. The short answer to your question is that no military designer anywhere, ever, would design the defenses of a warship (or anything else) to protect against ANYTHING except the weapons they believe are most likely to be used against them. That said, they might do so ACCIDENTALLY, but only if they thought they were solving a different problem. E.g. a hull material designed to make the ship more difficult to detect ALSO happens to dissipate energy from beam weapons so effectively as to reduce or prevent damage. This, ultimately, is the answer to your question though. If you're not actually fighting wars, you design your weapons systems to protect against the most dangerous stuff you can think of. This is what the US Navy has been doing for the last 80 years. If you're REALLY lucky, something you did to solve one problem ALSO solves problems you didn't know you had yet. [Answer] Historical experience is no guide at all if you are working in a new and unknown medium. To use an example, imagine asking a very knowledgeable officer in the 1700's how air combat might work. He might start with the assumption that air vehicles would be some sort of evolution of sailing warships. If he is really astute, he might consider that the newly developed steam engine might be somehow useful in flight [![enter image description here](https://i.stack.imgur.com/5zmuO.png)](https://i.stack.imgur.com/5zmuO.png) Miazaki airship The answers would include ideas like finding and gaining the weather gauge, crossing the enemy "T", debating using broadsides of cannon vs carronade.... They would never anticipate this: [![enter image description here](https://i.stack.imgur.com/TzSBj.jpg)](https://i.stack.imgur.com/TzSBj.jpg) Fokker Eindecker Let alone this: [![enter image description here](https://i.stack.imgur.com/6I5gH.jpg)](https://i.stack.imgur.com/6I5gH.jpg) F-35B Terminology like Immelmann Turn, "Boom and Zoom", Energy Maneuverability Theory, BVR combat, Stealth and so on would be totally meaningless, since there is no context or examples to draw upon. Space combat might be derived from "First Principles" if the nation creating the Space Force is lucky and has time to think upon and develop their ideas. The knowledge that space is vast, there is no stealth in space, orbits can be tracked easily and calculated months in advance, objects moving at orbital velocity have massive amounts of kinetic energy and there is no effective "terrain" in space can all be considered when designing space vehicles. Other technical considerations such as the need to carry reaction mass, heat management systems and so on also will constrain what the designers can and cannot do. Instead of the "cool" vehicles depicted in SF movies and TV shows, the vehicles will likely be very utilitarian in design; "Children of a Dead Earth" rather than "Star Wars" [![enter image description here](https://i.stack.imgur.com/GuQLf.jpg)](https://i.stack.imgur.com/GuQLf.jpg) Realistic space warship as depicted in Children of a Dead Earth Of course supposition and even careful thinking is not a substitute for experience. First generation space warships may end up more like a weaponized ISS simply because there is no true experience to draw upon, and multiple iterations might be needed to find a truely workable system. Even then, if the enemy is making different assumptions, the space warships might discover they are totally unsuitable for the mission. [![enter image description here](https://i.stack.imgur.com/1tGsH.jpg)](https://i.stack.imgur.com/1tGsH.jpg) "Lock S Foils in Attack position" So historical analogies will have no bearing on working in a different medium. This is why Armies, Navies and Air Forces in the modern world are different from each other (and indeed different nations use different doctrines and come up with different sorts of Armies, Navies and Air Forces based on starting with different assumptions). The Space Force will be in exactly the same position. and people who try to draw too heavily on Naval or Air Force historical examples will likely discover these cannot be effectively translated into Space without causing huge difficulties. [Answer] Civilization of fanboys. 1: Your civilization no longer actually makes war. It has not made war for generations. 2: Your civilization loves science fiction in which space aliens make war on each other. 3: Your military ships are art projects constructed by state-sponsored architects who are rabid fans of one SF or another. The ships are patterned after the fictional ships and crewed by like minded fans in costume. 4: Many aspects of these ships are impractical, but it is considered lame and cheesy to make ships that are just props. These ships have to actually replicate the performance of the fictional ships in so far as technology allows. These ships are capable of kicking ass in outlandish but awesome ways. [Answer] Well, form follows function, especially when it comes to weaponry. A space based battleship is a weapon, just like a club, a sword, a rifle....whatever. It's purpose is to project violent power. If you need to project that power on to a man in front of you, you take into account the weapons that man has. This grows in to Army tactics, Navy tactics and will inevitably into Space combat tactics. So your armor, drives, and weapons will reflect this. Throughout history, the army with better tech had a decided advantage in battles. I include deployment strategies for troops in this as well. When trying to prep for the unknown, that's where you run into a problem. If the potential enemy has a different method or weapon, YOU DON"T KNOW ABOUT IT. Of course you can't plan for it. At least not accurately. You aren't exactly helpless here though. What you need is some creative people who are in to games and puzzles. Set up simulators. Invite them to penetrate, immobilize, or otherwise beat the defenses as best they can. These people will guide you to things you haven't thought of. We humans are a pretty clever lot. Then you have to decide how defenses against these new potential threats will work, or if they are worth the effort. If someone figures out how to beat your platform but it would take a ton of luck, maybe you don't worry about it. Keep these creative in your back pocket, because you never know when you will need them. When you do get to the inevitable alien invasion, they may be able to spot enemy weaknesses or thought patterns faster than your generals (admirals, poo-bahs, whatever). [Answer] As a frame challenge here, we as humans have a few space ships under our belt already. None of them were warships. Some of them were adaptable to warships by bolting a bomb in place of the regular payload though. The story for all modern warfare is that the most powerful destructive force is the bomb or missile, and that can be fired from a very long way away. I think this is the lesson for space too. The main thing a space ship will need will be probes. The missile system for probes can just as easily have a bomb attached. The same system could also deliver anti-missile missiles. And the lesson so far from human history is that beam weapons don't work at a distance, I'm afraid. They're more useful for guiding that missile to a target. [Answer] Defenses are against weapons that are not used because the defenses are too good Imagine weaponry that is easy to defend against. For example, let's say you defend against lasers with a mirror and it's a highly effective defense, but other than that lasers would be highly practical weapons - they don't need a lot of mass, unlike bullets, and if a spaceship has no mirror surfaces it will be overheated quickly under laser assault. Everyone builds reflective surfaces - not 100% mirrors, but a good enough defense to render laser weaponry ineffective. So everyone CAN use lasers, but everyone defends against it. However, since it's reasonably cheap to retrofit a ship to carry laser weaponry, every ship requires a defense against it - otherwise their enemies will quickly attach a laser weapon to each ship and roast the crew alive. A different civilization might not use this defense for various reasons. Maybe their offense is ineffective or too effective, maybe it comes with dangerous drawbacks. A reflective surface might make the spaceship too easy to be tracked by homing missiles, for example. Defenses against non-military dangers specific to the civilization Ballistic weaponry, particularly railguns with small projectiles, might be another type of weaponry. The ISS is actually armored against (tiny, as in sub-1cm) projectile weapons at the front. Since it is on a low-earth orbit, it moves at about 7km/s around earth. Simply put, anything it collides with that comes from the front will impact with a relative velocity of at least twice that speed. That makes those projectiles dangerous and it would also make them dangerous for your future ships. The ISS is protected by a [Whipple Shield](https://en.wikipedia.org/wiki/Whipple_shield). There are some scenarios where one civilization might consider projectile weapons effective, while another doesn't because it requires natural protection against it. For example, if one civilization suffers the [Kessler Syndrome](https://en.wikipedia.org/wiki/Kessler_syndrome) with highly elliptical orbits it will defend against potentially larger projectiles from all sides, possibly with more than just whipple shields (think point-defense), whereas another civilization doesn't and thus might use them offensively instead. Similar non-military dangers could include charged particles, for example from earth's Van Allen belt - we defend our spacecraft against those particles by radiation-hardening our hardware in various ways, but it's not 100% effective - it merely decreases the chance of hardware failures. Alien civilization XYZ with much higher risks of radiation damage might use extra protection, such as hulls that are impenetrable for charged particles (too costly for earth). So Earth civilization might happily use particle beams for attacks while the XYZ aliens already defend against it. [Answer] RL case: the US does not use right now hypersonic missiles (that would require a highly expensive upgrade of their launching platforms just to accommodate bigger rockets, while the existing missiles are deadly enough). However, the US produced a small quantity of hypersonic missiles just to test their own defence systems. I see one case in which an army should actually design to counter a different type of weapons: No aliens detected => No aliens nearby => Any invader would have use ships with insane long range => Invader weapons would be optimised for long range ships => even though we don't have cruisers, we should invest in weapons that would be an overkill against our own ships RL equivalent: even though in littoral combat diesel submarines offer much better value for money, if one expects being attacked by some distant power, then should expect to rather fight nuclear subs. [Answer] I believe exploration will indirectly lead to some form of combat space ship. We already have very advance means of detecting stuff. So our combat sensors already exist. We now have the need to travel very far, very fast. When we accomplish this, the propulsion of the combat ship will exists. Perhaps ship durability is an issue here travelling at such speeds, so perhaps required alloys or some form of other (energy?) protection will also become researched and developed. Ship offense means (and defense if not already developed above as protection from extreme velocities) will mostly come out of our interaction with resources. Mining i believe is the reason we develop effective weapons. Because in order to exploit an asteroid we will need a series of weapons, from energy beams to mines, missiles and even drill-and-explode bombs. During exploration and interaction with the universe and its contents i believe we will get in time all the tech needed to build a combat starship. ]
[Question] [ We've found all sorts of interesting stuff in arctic ice & permafrost around the world. [Bacteria](https://www.scientificamerican.com/article/melting-glaciers-liberate-ancient-microbes/) & the like far older than the more media friendly [mammoth](https://en.wikipedia.org/wiki/Woolly_mammoth) specimens have been found, living bacteria has been found in ice cores as old as 420,000 years. Obviously I'm not thinking about living specimens. The ebb & flow of the ice & permafrost through our various ice ages are probably a factor in what might plausibly have survived unthawed to be found & by extension where ([not all](https://en.wikipedia.org/wiki/Ugrunaaluk) dinosaurs lived exclusively in warm climates) & when any particular species was found. So is a frozen dinosaur in any way plausible, how about a neanderthal? [Answer] Permanent ice caps have not been a constant during Earth history. For example we know that in the past the poles were free from ice. Therefore the oldest possible frozen sample is as old as the oldest permanent ice caps or frozen terrain on Earth. Anything that got frozen before that time has been thawed in the meantime. [Answer] The oldest frozen specimens would likely be roughly 15-30 million years old and would be whatever critters were on Antarctica during the [Oligocene](https://en.wikipedia.org/wiki/Oligocene) or early [Miocene](https://en.wikipedia.org/wiki/Miocene). Around that time, Antarctica finished its split from other land masses with the opening of the [Drake Passage](https://en.wikipedia.org/wiki/Oligocene#The_Drake_Passage) between it and South America, allowing the [Antarctic Circumpolar Current](https://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current) to begin keeping warmer waters away and permanently freezing the continent into what we know today. Until it fully froze, [conifer forests and steppes](https://www.sciencedirect.com/science/article/pii/S014663801730219X) covered the continent, and if Antarctic fauna were anything [like the rest of the world](https://en.wikipedia.org/wiki/Oligocene#Fauna) it was dominated by a mix of critters that were vaguely similar to today's large mammals, rodents, and sea life. So, it looks like your frozen Oligocene Park will probably be decorated with odd-looking pine trees, and be filled with horses and mice with weird snouts. Not as awe-inspiring as a T-Rex, but still pretty cool. --- As for finding frozen Neanderthals, it's possible but unlikely. In order to be found frozen, they would have needed to die in an area of [permafrost](https://en.wikipedia.org/wiki/Permafrost) that has been unchanged for the last 40-50,000 years, and [their known range](https://en.wikipedia.org/wiki/Neanderthal#Habitat_and_range) doesn't have many options for that. However, we did find a 5,000 year old [mummy](https://en.wikipedia.org/wiki/%C3%96tzi) frozen in the Alps, so anything's possible. [Answer] > > a study published this week (October 10 [2012]) in the Proceedings of the Royal Society B estimates that DNA from bone has a half-life of 521 years > > > ([Link](https://www.the-scientist.com/the-nutshell/half-life-of-dna-revealed-40361)) That's the rate the DNA molecules spontaneously fall apart. This study does not address DNA in tissue other than bone, or how freezing temperature affects the deterioration of DNA, but I think it's still a decent estimate to start from. How good is your technology at reconstructing DNA from teeny fragments in trillions of cells? Neaderthals went extinct 35,000 years ago. After that long (~67 half life periods) only 1/147573950000000000000th of the DNA will be left. The article sets 1.5 million years as the point after which DNA strands are too short to be read, but the point at which you can no longer recreate the whole genome might be much shorter than that. If your technology were impossibly perfectly accurate, you might be able to approach the 1.5 million year limit. [Answer] With a well preserved bone less than a million years old, you can do anything you want. > > Samples from a horse leg bone more than 700,000 years old have yielded the oldest full genome known to date. > > > The six-inch (15-centimeter) horse leg bone the team analyzed originated in the Yukon Territory of western Canada. Permafrost kept the remains in a kind of cold storage for about 735,000 years until scientists dug it out in 2003. > > > – World's Oldest Genome Sequenced From 700,000-Year-Old Horse DNA, [National Geographic](https://news.nationalgeographic.com/news/2013/06/130626-ancient-dna-oldest-sequenced-horse-paleontology-science/) [Answer] We have the actual example of the Ice Man -- beaker culture neolithic discovered in the Alps. He was about 9000 years old. So that can set some parameters: Hunter or band traveling across and icefield that is in a pocket between multiple peaks. Dies in late fall. Exceptional snowfall period, so is buried under permanent snow cover which as the ice builds up puts him deeper. Because it's a basin, the ice there doesn't move. When the ice builds up in thickness, there is a shear plane above it. Can't have glaciers feeding into the bowl either. So take a bowl that is surrounded by steep peaks that can avalanche into the bowl, but not form glaciers. Eventually the ice gets thick enough that it is above the bowl, and the excess flows off. I think the Columbia Icefield on the border between Alberta and BC fits these criteria. To me this would be a plausible event going back to the start of the last ice age. This would get you back to somewhere between 115,000 and 22,000 years ago. [Last Glacial Period -- Wikipedia](https://en.wikipedia.org/wiki/Last_Glacial_Period) For the longer period, you need to have some glaciation through the short inter-glacials. A mountain based shield would meet this requirement. If you want a story line, "My father's father said that he knew a hunter who had crossed The Pass of the Winds." But in the hundred years since the cooling climate has created a permanent snowfield there. Much of Antarctica is under water. Strip off the ice, and you have substantial inland seas. [Antarctica without ice](https://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwj75b_PkNfgAhXSuZ4KHXOqCdIQjRx6BAgBEAU&url=https%3A%2F%2Fwww.bbc.co.uk%2Fnews%2Fscience-environment-15735625&psig=AOvVaw0NhSj7R1aYMGtiWCLTirlK&ust=1551192486509925) You could have various things trapped by glaciers closing off the openings. I don't know to what extent these levels freeze down. If there were hollows above the then present sea level you could trap land animals as described above. This could plausibly take you back to the beginning of the Antarctic ice cap something like 40 Megayear ago. I suspect that the timing of that is vague, so you might plausibly extend it back some. Dig into Antarctic paleo climate. [Answer] It is an extreme long shot but it might be possible, some day. Not really frozen however. The extreme desiccating effects of amber has been shown to preserve DNA, even in specimens of the right time period. And at least one fragment of a [dinosaur flesh](https://www.sciencedirect.com/science/article/pii/S0960982216311939) has been found preserved in amber. Several feathers are also known to exist. The problems are three fold, not every piece of amber preserves DNA in fact most do not, and dinosaur material in amber are extremely rare, even by normal amber preservation standards. Lastly the DNA is extremely fragmentary so you are talking about massive reconstruction, to the point that said organism would be more invented than restored. It would also be the single largest and most complex genomic reconstruction in history, to the point you really would need a much better understanding of genomics and biochemistry than we have now. The only thing you have working for you is phylogenetic bracketing, and the fact said dinosaurs would be closely related to the ancestors of birds. In fact they would likely get more from reverse engineering proteins in the preserved specimen which survive much better, than the DNA, but that is an even more advanced technique. [Answer] An even more extreme possibility (very unlikely, something like winning the lottery 3000-4000 times in a row). Per [this article](https://www.technologyreview.com/s/425093/earth-ejecta-could-have-seeded-life-on-europa/), it is possible that ejecta after an impact from an asteroid could reach the space (even falling onto other planets). So, in case of a huge impact, a a rock sent into the space could countain some specimen (even a piece of a dinosaur, not necessarily a complete one). In the space, it should not decompose, so it could remain preserved, inside an asteroid in orbit around the Earth or somewhere in the outer space, until our days, where it could be retrieved by a space probe. Of course there are many issues to address (if you plan to write a novel, you would need some handwavium for them). In the impact it is likely that the organic matter would be carbonized by the heat. Such a specimen could be found only by chance, there is no way to detect it. Moreover (and most important), in the space there would be no decomposition, but cosmic rays would rapidly degrade the DNA of the specimen; even if it could find itself inside the rock, probably this couldn't provide enough shielding to allow the DNA to survive up to 65 milions of years. [Answer] The oldest known/recovered ice core so far is [2.7 million years old](https://www.sciencemag.org/news/2017/08/record-shattering-27-million-year-old-ice-core-reveals-start-ice-ages). It was pulled from Antarctica's Allan Hills area in 2015, which was coastal at the time the ice formed. Unfortunately the only animal specimens you'd be likely to recover from this site from this time would be marine lifeforms not too different from today's, as the continent had been cut off from South America for ~20-40 million years with the opening of the Drake Passage, which plunged the continent into the icy cold in the late-Miocene. ]
[Question] [ I'm writing a story with a fantasy-adventure-like background. The usual world where adventurers take quests and explore dungeons, but instead, I want my main focus to be on the support roles. Those include alchemists, blacksmiths, librarians, etc. The main character is Leo, an average alchemist who just opened a potion shop. His shop is right next to an average blacksmith, named Claire, who he is friends with. He was able to quickly grab customers by taking personalized requests for advanced potions. However, It got to a point where he needed to create potions in bulk by mixing a good quantity of ingredients in a cauldron. Leo decided to ask Claire for one. Claire is very skilled in what she does, but she lacks quality equipment and materials. Both of them have been switching favors between each other, and she feels like she owes him. With that in consideration, she will do her best for his request. My question is, how hard would it be to produce a large, good quality cauldron for alchemy? The best answer should: * Suggest a good material for a cauldron that consistently keeps an uniform temperature when over a heat source. Bonus points for resilience and cleanability. * Estimate the amount of time needed for Leo’s request. * Explain in some detail how Claire would create this cauldron. I have some knowledge in mathematics, physics, biology and technology, but the only thing I know about blacksmithing is that temperature is important. Edit: Claire has easy access to copper, iron, lead and tin, but she should be fine with spending a little more on rare/precious metals like silver/gold. Other metals like Chromium, Zinc, and platinum were discovered recently, meaning that smiths in general are not sure about their properties (but she might take this opportunity to test one or two). She is able to make alloys out of the previous mentioned materials. She is also not limited to metals. Claire usually uses coal, meaning that the highest temperature she can reach would be around 1900ºC. Heating speed may be to your liking. The technology she has available is similar to one we had at the end of the 17th century. Leo also explained to Claire that the measurements and ingredients used in the potion making process should be as precise as possible. If not, the potion’s effect is either downgraded, or worse, it can trigger secondary undesirable effects. This means that Claire might need to have special considerations because of any possible corrosion. He also warned that the cauldron might reach 200 ºC for long periods of time, not understanding if that makes any difference. [Answer] The easy, adequate way: Copper As per Xavon\_Wrentaile's answer, a simple copper of bronze (not brass!) cast cauldron will work just fine. The copper will help distribute heat. The material is strong and durable. It resists chemical, acid and alkaline attacks reasonably well, although it will tend to lose a bit of copper into any acid solution in it. Most importantly, it uses materials and techniques that are easily available to a blacksmith. not so easy, also not so adequate: Cast iron Exactly as per the copper cauldron, using a sand casting. The problem is that cast iron is quite brittle, very much more subject to contamination and etching by adicid contents than copper is, and worst of all: cast iron is porous. It absorbs stuff, potentially contaminating future project with residue embedded int he cauldron itself. On the positive side, the making of a cast iron cauldron should still be within the capabilities of a blacksmith, although much harder than making one from copper. The easier, but not so adequate way: Pewter Cast your cauldron from Pewter. This is easier even than making a copper cauldron. The materials are very easily sourced and handled. Unfortunately, its temperature resistance is not so great, and there is the small problem of it leaking lead into both acid and alkaline solutions within it. Lead poisoning is significantly worse than copper poisoning! There is also the tiny problem that the specified 200C heat tolerance requirement is very close to the actual melting point of the metal! Melted cauldrons would be a real danger. The ideal: but impractical to make: Glass. A good thick, strong glass cauldron, with no impurities, defects, bubbles etc. A good glass cauldron would withstand great heat, would not contaminate the contents, and would tolerate even the most virulent chemical concoctions that an alchemist could dream of. Glass does not conduct heat that well, so the user will need to be very patient, to prevent hotspots. The problem here is that making good glass, or even making any glass, is well beyond the skill and tool capabilities of a blacksmith. Even better, but impossible: Modern Steel The ideal material is of course a nice corrosion-resistant stainless steel. Good old modern cookware! Unfortunately, the making of suitable iron/chrome/nickel/carbon alloys is well out of the capabilities of a blacksmith. . . . Has your Alchemist considered not using the Blacksmith, but rather getting a nice line of disposable pottery cauldrons from the Potter? A glazed pottery cauldron should have similar inertness as the glass cauldron. Sure they will wear out much more quickly, but the cost should be immensely lower, and it allows for the idea of one-brew disposable cauldrons. Possibly even brew-in-storage-container alchemy? Guaranteed fresh, never removed from its cauldron, untouched by human hands. Fresh to you, the consumer as pure as the day it was made. [Answer] # Easily and quickly Given the very unrestrictive requirements, all Claire needs is some clay, two iron rods, enough copper or bronze for the cauldron, and a forge that can get hot enough to melt the metal. Make a clay mold of the cauldron. Use the iron rods to suspend the inner mold in the outer mold. Melt the copper/bronze and pour into the mold. Cool. Chip out the clay. Remove the iron rods (use the holes to attach handles). Polish. Deliver. [Answer] ### Claire might have access to materials other than iron and steel, but she wouldn't be legally allowed to work with them. Medieval cities organized skilled trades using the guild system, which was granted a legal monopoly within the city limits on the performance of their trade and the ability to set prices for the items that they produced. In particular, "blacksmith" refers to the smiths which worked with iron and steel; smiths who worked with other metals formed their own trades and own guilds (whitesmiths worked tin and pewter, redsmiths worked copper, bronze and brass, and goldsmiths and silversmiths often shared a guild), and Claire wouldn't be legally allowed to work with those materials - this could be considered analogous to how an electrician wouldn't be allowed to work on air conditioning units today, unless they were also certified as an air conditioning tradesman. If Claire is a journeyman or master blacksmith (and she would be, if she's running her own store and working independently), she would be well aware of this, and would operate within the constraints of her guild's regulations. If she's making Leo a pot, it would be made from iron or steel, because those are the materials she would be legally allowed to work with. If she wanted to work with other materials, she'd need to gain the approval of the other guilds of smiths first. [Answer] Although PCMan's answer covers most options in-depth, I believe he is missing the best solution which is tin lined cast iron or copper because it avoid the reactivity problems of iron/copper with acids. It does have a somewhat low melting point of ~450 degrees f (~230 c) but the inside of a cauldron shouldn't get that hot if there is anything in the cauldron (that's why tin lined skillets can be used on high heat well over >450 degrees). It would have been available in the Middle Ages (and before) and is still used today on copper pans. Yes, maybe strictly speaking a Tinsmith or maybe even the Tin Man would be the maker, not a blacksmith, but I doubt the question asker is concerned with that and the process is simple enough. Claire would cast the iron in a clay or sand mold as PcMan said, or hammer out the copper into its final shape. Then the cauldron is heated and some tin melted inside and brushed/wiped around until a thin coat is applied. The excess is wiped/poured out. Might the repeat process to even out. Should be able to find youtube videos of this process. The tin had to be periodically re-applied, probably on the scale of years unless Leo carelessly scratches it with a metal ustensil! Which could add opportunities to your story. [Answer] ## She may already have some cauldrons to sell cauldrons were a common thing for smiths to produce. Cooking in a pot was the norm for medieval and renaissance cooking. At the time bronze or copper cauldrons were more common but plenty of iron ones also exist. both could be made either by casting or riveting and/or soldering. Riveting is how the largest ones were made but cast ones tended to be thicker and this heated more evenly, so method depends on what you mean by "big". A real apothecary (potion maker) is not make huge volumes in a single pot, they would just have more pots to make more things at once. A large pot also means you will not have a consistent temperature, because you are cooking on a wood fire, which is not a precision heating method. hammered or riveted copper pots were also becoming common at the time, but it is unlikely a blacksmith will know how to do that, although she may very well be able to trade with the local coppersmith, there would be a lot of cross trade. coppersmiths would have and need a lot of blacksmith made tools so a trade would likely be easy, making such a pot would take a few days. Reactivity is not really an issue for an apothecary, they are not making anything terribly corrosive. If you need to make powerful acids you do it in clay pots. your apothecary may even already have a cast metal mortar. Making a cauldron should be something she has done often. Metal cauldron were very common in the medieval and renaissance period, this is the era of cast cannons after all. it was considered a step up from fragile clay pots that were also common. It should take a few days for a riveted one or less than a day for a cast one. You can find plenty of video on the internet of each being made, there area lot of people reenacting these techniques. Riveting is literally making the pot in sections and riveting them together and possibly soldered. Riveted pots often have to be sealed with lead after they are made to prevent leaks (sealing with tin is more common but will not take 200\C. Casting* would involve a clay or greensand mold that molten metal would be poured into. [here](https://www.youtube.com/watch?v=XcxDY7vQnPo) is a great video of casting a cooking pot, the process would be very similar. She may also have a broken one that can be fixed, many cauldrons show signs of repair (mending), usually patching a crack. Some visuals to see what you are working with. Recreation of a riveted iron cooking pot [![![enter image description here](https://i.stack.imgur.com/F6FHS.png)](https://i.stack.imgur.com/F6FHS.png) medieval cast iron cauldron [![enter image description here](https://i.stack.imgur.com/buUxW.png)](https://i.stack.imgur.com/buUxW.png) Medieval cast bronze cauldron [![enter image description here](https://i.stack.imgur.com/7zwZq.png)](https://i.stack.imgur.com/7zwZq.png) Medieval riveted bronze cauldron [![enter image description here](https://i.stack.imgur.com/wnaSF.png)](https://i.stack.imgur.com/wnaSF.png) Metal cauldrons were quite common. Example of a Medieval field kitchen from Il Cuoco Segreto Di Papa Pio V (The Private Chef of Pope Pius V), by Bartolomeo Scappi, Venice, 1570. [![enter image description here](https://i.stack.imgur.com/0x4PB.png)](https://i.stack.imgur.com/0x4PB.png) Plate showing 17th century coppersmiths making cauldrons of various sizes. [![enter image description here](https://i.stack.imgur.com/AMW9C.jpg)](https://i.stack.imgur.com/AMW9C.jpg) [Answer] ## The Gold Standard: The two most important metals in alchemy are gold and mercury (and I'm hoping you aren't adding mercury to your potions). If inert is critical, then plate the inside of your cauldron with gold. Even a cooking pot lined with gold will be a cauldron. Its chemically inert properties were deeply important to alchemy, and [Aqua Regia](https://edu.rsc.org/magnificent-molecules/aqua-regia/3007792.article#:%7E:text=Although%20gold%20is%20typically%20an,of%20nitric%20and%20hydrochloric%20acid.&text=Once%20this%20ionic%20form%20is,form%20tetrachloroaurate(III)%20anions.) was needed to dissolve gold. The whole quest for the [philosopher's stone](https://en.wikipedia.org/wiki/Philosopher%27s_stone) was about making gold from base metals. The melting point is higher than people think (1064 C) but it is fragile, so it would need maintenance. Use a gentle mixing tool to cut down on wear. But chemically, the stuff is extremely inert and will be useable over and over. It would heat well due to its extremely high thermal conductivity. Plates of gold are extremely easy to work with and the whole task could be done very quickly. If cost is not an object, then make the whole thing from gold! Casting gold is relatively easy, and could be done with [sand and wax](https://en.wikipedia.org/wiki/Sand_casting) (or simple clay) as is often done today with the production of bells. A wax cauldron is made, packed with sand, fired to melt out the wax (the sand hardens) gold poured in, then the sand is simply chipped away. Otherwise, gold is amazingly malleable and the whole thing could be pounded out. The whole thing can be supported on the outside with other materials to give it greater structural support if needed. [Answer] There are several options which come to mind. Probably the simplest is go down to the potter and buy or commission a clay pot. Or Clare could try making one her self``. A more obvious answer is just get her to beat out a caldron from either copper or iron/steel. I have made small copper bowls with just a concave surface cut into the end of a piece of wood and a peening hammer. It just takes a lot of carful taps and you can stretch the copper in to shape. You can soften the copper (which work hardens) by heating it and then quenching it in water (Which is the opposite to steel FYI), as you go. Here is a very crude version: <https://www.youtube.com/watch?v=7e6Z9QQieAk> And here a craftsperson making more complex copper tea pots etc: <https://www.youtube.com/watch?v=odWl4M-Pzw0> Being a blacksmith Clare could quite easily do something in-between the two. The same thing can be done with an iron/steel. It just requires more heating and beating. But that is something Clare already has the skills and equipment for. --- ``FYI here is examples of the simple tools etc which are required to make suitable sized and shaped pottery pot/caldron <https://youtu.be/52HKSwkI1hs> [Answer] ## Alchemical Glazing Gold is fairly unreactive, so are glass and ceramics. Even copper/iron can last a while. But why limit it to mundane materials? Your alchemist can take an ordinary cauldron, and buy a small batch of expensive ingredients from adventurers to make a magically inert (and reasonably tough) coating on the inside. Claire's role in this can be as involved as you wish, and use any of the above manufacturing techniques. Of course, this glaze may require regular reheating, or corrode the copper on the outside. Or the tools used to make the glaze may be sacrificed, so the smith has to make/repair them. ]
[Question] [ Excerpt from the great Dalian Holy Book *”The Dark God, the Tayan, was first formed when the gods above sent a curse down to the surface, to remind our people of our dependence on our gods. If the Tayan is not fed, it will rise from its slumber in the underrealm and devour the Cosmos”* I have been working on a creature lately, called the Tayan. It is a biologically engineered being, created by an amazingly advanced civilization to be used as a torture device. Creatures the sizes of Earth bears can be swallowed whole and land in the Tayan's stomach, where they are slowly digested over 5-30 years in agony. *Digestive System* The Tayan, during its adult stage, is immobile and waits for prey to fall into its sand trap. The sand trap is angled in a way so that when a creature tries to climb out, the sand crumbles away, and they fall into the Tayans mouth. Inward pointing, slippery teeth make sure that prey can't climb out, and its tentacles, mostly its main tentacle, help drag prey down. Prey falls into the Tayan's throat. A muscular flap separates prey into one of two stomachs. Larger prey goes into the main stomach, smaller prey goes into the secondary stomach. Once inside their respective digestive chamber, prey is held back by tentacles to the Tayan’s stomach walls, were needle like tendrils inject prey with a paralyzing neurotoxin, that also causes intense pain. Prey wearing synthetic clothing can not be injected with neurotoxin. Digestive juices slowly eat away at the prey's skin, until they resemble skeletons, with only their nails, hair and (sometimes) eyes still (mostly) intact. Full digestion takes 5 years in the main stomach, and 30 in the secondary stomach. Prey is alive during this entire process, as the Tayan injects their brain with nutrients, and acts as a biological dialysis machine. Intelligent victims have their consciousnesses saved by the Tayan, and essentially become one with the monster, living out the Tayan’s 10,000 year lifespan with it. *Here is a visual representation for your convenience. My main character is in the secondary stomach* ![](https://i.stack.imgur.com/9JsSV.jpg) So, now that we have that out of the way, let’s cut to the chase. The specific Tayan in this drawing lives in a semi-arid climate, were sand storms often hit, and when prey struggles to get out of its mouth, sand falls into its mouth. The Tayan cannot digest sand at all, and if too much sand fals down its throat and into its stomach, it would die. So, my question is how could the Tayan keep sand out of its mouth? [Answer] What if some sort of symbiotic insect removed sand from the creature's body? The Tayan has its body cleaned, and in turn, the insects get to feed off of the victims. As far as the victims are concerned, its just another layer of torture. [Answer] When snakes or owls eat their prey, they later vomit the non digestible parts (hair, bones, hoofs). Your creature can use a similar approach. Casually ingested sand can be agglomerated by some mucus contained in the upper part of the throat, and the balls of mucus and sand can be the simply spit out from the mouth of the creature. For bonus, the creature can spread the mucus balls on the sides of the trap, so that when the mucus dries up it can leave the slippery sand in place. [Answer] Sand removal could work the way it works in oysters. The Tayan can form a pearl-like coating over the sand layer by layer. Then the Tayan can use its tentacles to move the pearls just outside the mouth of the Tayan. The pearls would be a status symbol for any warrior who manages to get to them without falling in. The Tayan wouldn't mind this because that is more would-be warriors falling into its mouth. People would notice the Tayan in a sparse desert pearls or not, so camoflauge doesn't matter, and the pearls would attract crows and children because they are shiny. [Answer] The Tayan simply swallows the sand and passes it through its digestive system. Several species of worms living in mudflats do this, like the [lugworm](https://en.m.wikipedia.org/wiki/Lugworm). Lugworm swallow sand and filter it for nutritious particles, but since sand itself is not digestible, it's excreted unchanged, creating distinctive forms. [![enter image description here](https://i.stack.imgur.com/wYRBK.jpg)](https://i.stack.imgur.com/wYRBK.jpg) By excreting swallowed sand, the Tayan can incorporate it into its sand trap, increasing the height of the traps funnel without wasting energy for digging. Both stomaches hold back big chunks for a long time but let small particles pass into the intestines, thereby quickly emptying of swallowed sand. Since the sand is drenched in saliva and/or stomach acid, it moves through the intestines as easily as any regular food. [Answer] If the Tayan closes its mouth while resting that will definitely help! think of it like a biological trap-door over the mouth opening, upon feeling footsteps above it, the trap-door suddenly opens and the Tayan feeds as normal. The fast jerking movement of the door is analogous to the pouncing of snakes or the snapping of venus fly traps. This will stop sand falling in from sand-storms but some sand will still get in during digestion. That I advise you deal with the same way humans deal with sand getting in our digestive tracks! Sand is biologically inert so while indigesitble can ultimately be passed with little difficulty by whatever consumes it. This is assuming that the Tayan has an, ahem, other end. (possibly going back up to meet the surface?) [Answer] You can design filters that let in big things but not small things. Whales come to mind Multi stomachs make sense, just not how you expect them. "Traditional" wet mouths feel like a problem though. So something that acts like a big mesh bag as a first stage. Have it "breach" the sand, and let the excess come out, and blast the rest out, as it poisons the victim. That minimises the sand ingested. Then shut the sand exhaust orfices and pull the stomach in before transferring it to the "Wet" stomach for your long and painful digestion needs. So have a "dry" stomach and "baleen" handle the sand, use the tentacles to pull in the victim and digest with minimal sand intake in the "wet" stomach. Might even have an intermediary stage to clean the victim, maybe washing them in some mild and very painful stomach acid or neurotoxin that periodically gets flushed into the surroundings. [Answer] The digestive system has a filter. Specifically, from the mouth downwards there is a steep slope to one side. The slope has little holes where sand falls through and out of the Tayan. Prey doesn't fit through the holes and slides down the slope. If you want, you can use this to separate between the stomachs too. Another set of holes for small prey further down the slope makes that prey fall into the first stomach. Only what's too big for those holes goes into the second stomach at the end of the slope. Makes for interesting plots, too. Trying to cut a hole into the first filter to hop out or closing the holes to make the Tayan suffocate from the sand that isn't filtered out anymore. Bonus points: it's a mechanical solution, your Tayan is already wasting a lot of energy with those tentacles and keeping prey alive, it needs to save energy at some point. If it was engineered, that's basically a design choice. [Answer] IT CAN SPEW SAND OUT TO COVER ITSELF AND HIDE IN PLAIN SIGHT My creature, which is heavily inspired by yours, has a similar problem and deals with it by turning itself into a glorified biological pit trap that uses the sand to help it hide in plain sight. I'm just going to quote a question relating to this creature. > > Its mouth remains closed, sitting just below the surface and covered in sand until it senses a victim above it. At this point, the creature's mouth opens, and the sand falls into the creature's throat, along with any hapless victims that may have been on the sand (kinda like the 'death from below' attack used by a sandworm on a spice harvester in both the trailer of the latest Dune movie and the movie itself). Tentacles within the throat reach through the sand, grabbing all living things within a certain size range (by the way, humans of all ages and sizes fall within the alforementioned size range) and ensuring that anything stuck on, carried by, or attached to the grabbed victims (such as parasites, clumps of sand, or in the case of humans, clothing or equipment) is removed. Once this is done (it typically takes just under a minute), the creature vomits everything not grabbed by the tentacles up out of its mouth and high into the sky above it and then shuts its mouth. The falling sand then lands on top of the creature's closed mouth, and the trap resets. As an added bonus, anything of value also lands atop the mouth, serving as bait for more prey. > > > Your Tayan could do something similar, setting itself up as a pit trap that situates the tentacles inside its throat, where they grab prey before the Tayan chucks everything out of its throat, to ensure prey can't escape via being spewed out with the rest of the sand. ]
[Question] [ In my science fiction story, there is an extraordinarily powerful species of alien that can teleport humans. They do this by disassembling a person's body into molecules or atoms and simultaneously reassembling it in a different location using other molecules. My concern is how the person could retain their own consciousness and identity doing this. Their teleported self is essentially a copy, so shouldn't their consciousness be a copy? Then the person effectively dies in the teleportation process, being replaced by a person with their body and memories. This is not a satisfactory teleportation process for me, so I am wondering if there is any way for the reassembled person to not just have a copy of their consciousness, but to retain their actual consciousness so that the person feels like they have teleported and not just spontaneously died. I personally don't think it's possible because if the alien were to not destroy the original person's body, then there would be two copies of that person at once, and that seems perfectly plausible. The same issue comes up when considering how the alien can "revive" a person that has been dead for a long time. The alien does this by observing light at a distance from the body that was reflected right before the person died and then assembling atoms in that exact configuration surrounding whatever remains of the person. But this has the same problem that the teleportation does, so is there a way for dead organisms to be revived without being copies, especially considering that there is no way to teleport organisms from back in time, when they were still alive? My big question is if I were to implement teleportation or revival of dead organisms in this matter and assume that it works properly, i.e., the identity is preserved, then are there any physical laws that this clearly violates? [Answer] Momentary soapbox I apologize, but the current fad of trying to make every aspect of fiction factual is a bit absurd. The trivial answer to your question is, "insofar as we understand science today, teleportation is impossible so the question is moot." If we insist on extending the question to account for teleportation, then the answer is, "insofar as we understand science, there's no way to resurrect the soul." (I'll touch on the greater issue about this later.) That's the problem with trying to make fiction factual. There is no science today that can predict what "teleportation" (whatever that may be) will do or must be or what can or cannot happen to the body. There's only what we can or cannot do... today. Please remember that our goal is to help you create and consistently use rules for an imaginary world of your own creation. At best, we can use what we understand of science today to help you rationalize your fiction. Far too often new users come to this Stack hoping that we won't do any of that, because what they want is to be told that science proves their ideas. That's not what we're here for. As you ask questions, please remember that we're here to help you create fiction. OK, sorry. Soapbox mode off. What are your options? The goal isn't to find a scientifically credible method of teleportation. If anyone could do that they would be running for the patent office, not explaining it here. The goal is to use what we know of science to rationalize your goal. What is your goal? A method to transportation that covers long enough distances over a short enough period of time to be considered reasonably "instantaneous" without resorting to a method that invites people to wonder what happens to the body at the beginning of transport. Let's begin... The Einstien Theory: e=mc2 Accelerate the human body to the speed of light and it becomes pure energy. Slow it down and it's back to classical mass. Teleportation isn't so much the Star Trek vanish here reappear there solution, it's more like the old Sci-Fi show The Time Tunnel. Since the "mass" of the body is part of the transport process, the body and its consciousness are preserved. The You're Only a Copy Theory: Simplifying to the point that angels weep, the human body is a combination of atoms and energy states. If you can map the "current state" of all the atoms and energy states and send that map somewhere else, you can reassemble the atoms with the appropriate energy states and, boom, you have a completely functioning person exactly as they were when the map was made. Of course, once you have a map you can copy people over and over, which was kindof the premise of the Star Trek: The Next Generation episode Second Chances. The problem with this method is that the original body doesn't actually go anywhere, so either there's two of you walking around or the first body must be destroyed (usually as a byproduct of the map-making process). The Portal Theory: Wormholes, star gates, video games... The concept of "teleportation" is sometimes too stuck in the Star Trek version of the concept where someone disappears in a flash of light and reappears somewhere else. But teleportation is just a really fast way of using a door — and it's the door that's the problem. You can convert the body's mass to energy or vaporize it making a map, but you must still transport something somewhere else to bring said person back. Why dematerialize anyone when you can open Ye Ol' Einstein-Rosen Bridge and simply walk through it? Unless you subscribe to the Stargate solution, which resolves the "what happens when your nose moves away at the speed of light and your heel doesn't?" problem with the explanation that the interface to the wormhole dematerializes the body so that it all moves at once. (I touch on the greater issue with this later, too.) The Dimensional Travel Theory: We think there might be a few more dimensions or parallel universes or something like that out there than we can see or measure. Stepping outside our universe and traveling through another one has the benefit if having any set of rules possible and plausible vs. science. The idea of "phase shifts" and "time shifts" and dimensions and parallel universes has been explored over and over in science fiction. Honestly, it's the most magical of the theories because while the concept exists mathematically there's absolutely no physical evidence at all that any of these things exist. Consequently, we have no idea what the rules (aka "physics") of those conditions are, and therefore it's perfectly reasonable to say that you can use them to transport the body and mind without destroying either. Magic & Religion: Just to try and round everything out, there's the theoretically non-scientific solutions ascribed to magic and religion... except that Clarke is completely right: a sufficiently advanced technology is indistinguishable from magic. Therefore when we consider Jesus Christ's miracle of passing unseen it's as reasonable to assume He was using some technology we're unfamiliar with. Agree or not, it's irrelevant. I'm just making the point to be thorough. One last word... The problem with trying to crowbar fiction into real world science is that it's a house of cards that's easily blown over. Every example I've given you can be examined in much more scientific detail than I have used — and when you do that every one of them utterly fails. That's the basic problem. Insofar as we understand science, teleportation isn't real and resurrection isn't possible. You can make them sound real with a little rationalizing — which is what even the most hard science sci-fi writers do because they're not writing documentaries — but if you try to make your fiction real, science will fail you. Science is a harsh task master. [Answer] As far as I'm concerned, teleportation is just another decorative wrapping for the ship of Theseus: <https://en.wikipedia.org/wiki/Ship_of_Theseus> And thus, every day you die a bit, get replaced a bit, get changed a bit and many bits maketh the byte of time. The you who asked the question yesterday is gone, teleported into the you of today; yesterday is but a dream, a ghost of a world that was. Are you the same? Yes. As in a ripple of cause and effect, the eddy swirling onwards through the entropy was caused by the same stone. Is the teleported eddy identical? Yes, again. [Answer] This sounds like [Derek Parfit's version of the teletransportation paradox](https://en.wikipedia.org/wiki/Teletransportation_paradox#Derek_Parfit%27s_version). Cognitive scientists are still arguing about what consciousness is: does it arise merely from the positions of atoms, or is there something else? Is that something else physical? (I'm thinking of a spinning top. Copy the positions of all the atoms, and you're still missing something, the motion of the atoms. Could consciousness be something doing something?) Once they resolve that issue, your question will probably be easy. [Answer] For what we know, consciousness emerges from the neural activity, which in itself is a complex interaction of quantum states of all the molecules involved at neuron level. If your alien is capable of replicating the being A into a being A' which is exactly the same even at quantum level, it reasonable to assume that also the consciousness arising from those quantum states would be the same. [Answer] The question is primarily philosophical. For all external observers, including the teleported person after the teleportation, it will be indistinguishable whether the result of a teleportation is a copy or the original. There is no in-universe way to measure whether it is one way or another. The only difference is whether "the story ends" from the perspective of the person being teleported, which is impossible to determine. It is a matter of "philosophical taste" - whether one subscribes to form tracking identity or spatial tracking identity: * Form tracking identity: a person is the same person (i.e. the original, not a copy) it their physical composition (form) is the same. * Spatial tracking identity: a person is the same person (i.e. the original, not a copy) if their [world line](https://en.wikipedia.org/wiki/World_line) is continuous. From the standpoint of the form tracking identity, Star Trek-like teleportation is fine. From the standpoint of the spatial tracking identity, it is not. There are many (philosophical) arguments for one and the other, which is a part of the [teleportation paradox](https://en.wikipedia.org/wiki/Teleportation_paradox) debate. Perhaps a consistent purely form tracking identity standpoint is a bit problematic because e.g. it would effectively make everyone immortal in an infinite universe because, no matter what happens, there is an arbitrarily similar version of anyone that survives any event. That would be conceptually similar to [quantum immortality](https://en.wikipedia.org/wiki/Quantum_immortality), but with branches of a wave function being replaced with the spatial infiniteness of the universe. [Answer] # A person and their brain Consciousness and identity is something not yet understood, but there's a lot of philosophy about. There are many who would argue that an exact copy of you is still you. They have your exact memories, personality and more, with the only difference at the time of duplication being the physical position they are in. The reason they think it's no different derives of your brain. The brain is in constant motion, both recreating and updating itself. Imagine having a tiny rowing boat called 'Two Oars'. You build it bigger. It is now a sailing ship. You build it bigger. It is now a three masted galley. Is it still the Two Oars? It still has that beginning in there. Much like a child to an adult brain, it is now something different, while still somehow being the same to everyone. We now call our boat 'Three Masts'. A sail rips and is replaced. Tar is reapplied. Planks need renewal. The rigging is done in the new fashion thanks to technological progress. The steering wheel has broken. At one point the whole ship is made out of new parts. Would that make it still the Three Masts, or something different? If someone secretly kept all materials of the ship and build another exact replica. Would it be a new ship? Would it be the Three Masts? This exact problem happens with people. We grow, we age, we get new neuron connections. Hell even when we're hungry we have a wholly different way our body reacts, and thus are personality, compared to when we've eaten. Or if we are sleepy or angry or happy. That is why it is currently ok to say that a duplicate is still you, or a different person. It depends on how you look at it. We have no definitive answer and it doesn't look like we will soon (or ever) get a solution. My personal idea is created out of my own experiences. I say it is a different person, a duplicate and that the old one is killed. I say it because identity is more important to me. As an identical twin it is more important to make such distinctions. I am not my identical twin, even if the world has had a lot of trouble seeing it my way. They've seen the same person for years in both of us. We're all a product of our experiences on that regard. [Answer] Easiest way is to separate the consciousness from the corporeal, then transport the body any way you want with the consciousness tagging along on its own as it's not tied to any physics we understand. The same way many people believe the spirit can travel and return during dreams, etc. [Answer] > > My big question is if I were to implement teleportation or revival of dead organisms in this matter and assume that it works properly, i.e., the identity is preserved, then are there any physical laws that this clearly violates? > > > Yes. [Heisenberg's indeterminacy principle](https://en.wikipedia.org/wiki/Uncertainty_principle). In order to reassemble someone or something remotely and preserve all the states and interactions between the parts, you need to perfectly know every particle's positions and momentum (as well as other pairs of properties protected by the principle). You either get an imperfect "copy" or at the very least a fine from the auditors of reality. It would even be plausible that a copy of a person might be unstable (chemically and physically, I mean). [Answer] Science is mostly based on materialism — we are the configuration of our bodies, so an identical copy isn't "just" a copy, it's you, again. This doesn't feel like it meshes well with our subjective sense of continuity. If I should suddenly die, it seems to me there's all the difference in the world between the me writing this resurrecting and a copy of me. As far as I know there's no real answer to this. "People have souls that are made of `energy`" is often used as a placeholder, but it just moves the problem. What if you copy the soul, etc? I can offer just one point out of recent science that might be useful for your story, especially if you're willing to bend physics a bit. You may know that quantum physics implies a certain amount of fundamental uncertainty in the position and momentum of particles. I cannot take particle A and copy its state exactly to particle B because I cannot measure the state of particle A exactly. This is a universal law - if I could copy A, then I could simultaneously measure both copies and get more information about the particle than can exist. The one exception to the no-copy rule that has been found is that if you have two entangled particles (call them X and Y), you can take a combined measurement of A and X, then apply that measurement to a combination of Y and B in such a way that particle B takes on the exact state of A. The result of the operation ruins the entanglement of X and Y, and also changes the state of A. Thus you can "teleport" the information from the location of X to Y, but are fundamentally prohibited from copying it. Does this mean you "can't copy identity?" Not necessarily — we're changing all the time anyway, and just because you can't copy a given particle doesn't mean you can't copy something much more macroscopic - say a computer program. Does consciousness exist at the level of a computer program, or deeper in uncertainty? For the sake of your story, you can easily say the latter. Add some hand-wavey bits about establishing entanglement over great distances and you have a can-transport-but-not-copy device with room for singleton identity (and also some interesting possibilities to imagine on what you get if you do try to copy - what do you have if you have all the neurons in the right places macroscopically but the quantum states are all randomized at a deeper level? A new person? A gibbering deranged monster? Does the scrambled brain fundamentally just not work?) [Answer] # Consciousness is Quantum If you explain consciousness as arising from a quantum state, the [no-cloning theorem](https://en.wikipedia.org/wiki/No-cloning_theorem) says that you could only ever have one copy (i.e. there is only ever one You, whether it is currently represented in the flesh or simply as electrons with quantum data encoded as spin). Now, if this concept of "quantum consciousness" were made up for your story, it wouldn't help you any, but this is actually a [real theory](https://en.wikipedia.org/wiki/Quantum_mind) that is currently believed by [real neuroscientists](https://theconversation.com/can-consciousness-be-explained-by-quantum-physics-my-research-takes-us-a-step-closer-to-finding-out-164582). [Answer] ## If souls exist, definitely not Reconstructing an exact copy of your molecular and atomic structure does not preserve one's soul and would therefore not preserve your consciousness. ## If souls do not exist, still probably not You would need to create an exact copy, potentially down to the quantum level or beyond, on the other end to ensure it truly is the same consciousness, and it would need to be done fast enough to not interrupt chemical or electrical signals for it to be perceived as seamless to the person being teleported. There is a submicroscopic tolerance for error, and a very high probability of bits and pieces of the teleportation signal to get corrupted or arrive out of order. Such a process would also essentially be a nuclear bomb on the deconstruction end and require an equal amount of energy on the reconstruction end. You would probably die mid-teleport. Deconstruction and reconstruction would undoubtedly have thermodynamic effects, so to preserve temperatures of all the atoms in the body (which is necessary for an exact, stable, and safe reconstruction) is actually insane. That's not even getting into the relativity involved in the idea of "simultaneously" reconstructing the human on the other side. You have the speed of light to contend with. ]
[Question] [ In space, normal weapons are so easy to dodge because by the time you see an enemy ship and fire at it, it's already moved out of the way. Now imagine a weapon that travels backwards in time as it flies though space so that when it arrives at its target, it converges with the exact time and location that you saw the target when you fired. So, if an enemy ship is 5 light minutes away. Then your shot travels back in time 5 minutes as it closes the distance eliminating all guess work about where the ship will be. For purposes of this question, assume this weapon can only travel back in time as fast as light can travel forward in time. So you can target a thing in the past exactly where you see it now, but you cant target something you saw 10 minutes ago. While such a weapon would seem to work without any major paradoxes when you just have one ship shooting another, what would happen if 2 ships shot at each other with such a weapon. Since both ships could in theory be destroyed before either ship actually fires thier weapons does there need to be some rule that one event will take precedence over the other, or is there a logically consistent way for both ships to destroy each other in this manner since neither ship captain could see any future events that might cause him to change his course of action. [Answer] ## Frame challenge A time-travel paradox is by definition an inconsistency that cannot be resolved. This is why people think it's so important to avoid them: because it is logically impossible to resolve a paradox if one arises. Thus, there is no "logically consistent" way for this to happen. You are going to have to invent some new rule that defies ordinary logic. As the author, you can do this! As the author, you cannot decide whether your audience will buy it. We like to think that one of the best ways to ensure that audiences will accept our narratives is if we stick within the bounds of conventional reason. But works like Star Wars and Star Trek do all kinds of things that are patently absurd, and that has not stopped countless people from enjoying them. [Answer] there is no Paradox As written in the question > > Then your shot travels back in time 5 minutes as it closes the distance > > > the shot doesn't begin its trajectory 5 min back and then travels to the enemy. Instead it travels back in time by moving toward the enemy. So i agree with ivo's comment and mostly with JBH' answer except for his proposed paradox. Because the shot isn't send back in time but travels backwards while moving there is no way to detect it before it hits. It would just seem to materialize into the enemy ship. It seems to me that this is just a "teleportation weapon" in effect. You press a button, and in that instant your projectile hits. No time to dodge or even realize something is closing in, so no chance for dodging and the resulting paradox. (To be fair this is a jab at the other proposed answers, because they use it as an example of the loop that can result when the shot is send back in time and then travels toward the enemy.) On a timeline it would seem to work like this: T0 You spot the enemy. T0 You fire and see the enemy getting hit. In full: T-5 The enemy reflects the light you see at T0, your projectile hits. T-4 Your shot has traversed 80% of the distance and moved 4 min backwards in time. T-3 Your shot has traversed 60% of the distance and moved 3 min backwards in time. T-2 Your shot has traversed 40% of the distance and moved 2 min backwards in time. T-1 Your shot has traversed 20% of the distance and moved 1 min backwards in time. T0 You spot the enemy. T0 You fire and see the enemy getting hit. [Answer] # Whoever hits first gets to control the timeline. If ship A hits ship B first, then ship B can't fire at ship A. Therefore, their temporal projectile vanishes, and they do no harm. Example. 1. Ship A's projectile goes back in time and Ship A and B fly unaware. 2. Ship A and Ship B see each other. 3. Both ships prepare to fire back in time, but Ship A fires first. 4. Ship B explodes immediately from the back in time projectile. [Answer] What paradox? All ships are 100% automatic (it doesn't matter if it they are or not, it's just easier for the explanation). The moment my ship detects the enemy ship, it fires the weapon. The very moment the circuits activate the weapon, my enemy is hit. Ditto for my enemy, which did the same to me. Where's the paradox? If my ship detected the enemy ship first, the enemy ship won't get a shot off. If the enemy ship detected my ship first, I won't get a shot off. If we detected each other simultaneously, neither of us will be around to argue about whether or not there was a paradox. But I want a rule! I literally can think of only one scenario where a paradox can occur. Your detonation can occur *before* the weapon is activated. In that case, the paradox of your ship destroying another ship, but you were destroyed before you activated your weapon, could occur. Rule: don't do that. Regardless the range you wish to give your weapon, no detonation can occur before the weapon is activated. In other words, time travel in your universe is causal. No paradox can occur because no effect can occur without the cause that brought the effect about. And why do you want your rule? Because if you didn't then all it would take is one drunken sailor ordered to fire the weapon to look at his friend and say, "watch, this will be funny" and not push the button to rip all of space and time apart. You don't want that. Nobody wants that. Well, psychopaths might want that. But we're not psychopaths, right? RIGHT? [Answer] No real paradox free time travel Unless the time travelling component is required, you can get around this by making weapons fire their projectiles at very near light speed. You could say they somehow weaponized neutrinos or something similar. This would have very similar results in that the attacks are unable to be dodged, undetectable, and can only hit a target where they are currently at (unless they are extremely far away). Another good way to deal with this is treating the shots as instantly teleporting the distance as Mileonen mentioned. While this does result in problems of FTL travel, those are a lot easier to ignore than time travel. The paradox you proposed of not having a ship to shoot at so why shoot does happen anyway regardless of whether there are the two ships are firing at each other. If the ship is destroyed before you would have pushed the button to fire, then there would be no need to press it in the first place so you wouldn't have fired the shot that destroyed the enemy ship. If the time travel is important I would follow what JBH recommended and make a rule where time travel is causal. Another way around this might be that the weapon's computer and projectile exists in its current state across time eg any firing information and the fired projectile exists on it in the past present and future. With the time of the attack being part of the firing information the projectile will only meaningfully "exist" only for the moment it strikes the target. This, along with the firing information only meaningfully existing for the crew when the data is entered and after that, would remove the paradox (or at least make it feel like its not there, there is probably something I am overlooking). This is a lot more complicated though. [Answer] Suppose that [Novikov's self-consistency principle](https://en.wikipedia.org/wiki/Novikov_self-consistency_principle) applies. In this scenario, there are two outcomes that are each self-consistent: ship A destroys ship B before ship B fires, or ship B destroys ship A before ship A fires. Which of these outcomes actually occurs is a matter of random quantum mechanical probability, determined by a sum-over-histories wavefunction result that I suspect may be infeasible to calculate for any semi-realistic scenario at this scale. [Answer] I think the paradox can be resolved by adding a necessary delay: mass prevents time travel. The mass of the firing ship means the weapon needs to travel a bit before it can start traveling backwards, and the mass of the target ship likewise causes the weapon to reenter normal time a short distance away. Just tune the effect so the arrival time is too small to allow a response and the weapon will largely function like you want. The mass of the weapon itself isn't relevant, as the whole thing will time travel. The relative masses of the two ships is also not important, as the departure delay for one ship;s weapon will equal the arrival delay for the other ship's weapon, so the total trip is functionally symmetrical in both directions (less massive ships would have a slight advantage in departure time, but an equal disadvantage in arrival time). So simultaneous shots will both arrive, as the two shots will have time to travel before their source is destroyed. Near simultaneous shots will also result in both ships being destroyed, due to the delays. Super massive ships (I'm thinking planetoid mass) would have enough arrival delay to respond with point weapons, but the cost to make, move, and maintain such a ship would be prohibitive. Likewise, the time travel feature of the weapon isn't usable too close to a planet, or more likely inside a solar system at all. Maybe outer reaches are low mass enough. Battle fields with asteroids or debris or whatever would require carefully aimed shots to avoid having the weapon knocked out of time travel too soon. [Answer] Seems to ME that it's really contingent on the mechanic by which you decide time "actually" functions. Even Einstein and Hawking kinda "settled" into the whole infinite parallel universe thing for lack of better means to reconcile these sort of incongruities. Fact is, for you to have cause and effect, action/reaction, determinism/consequence, there's ALWAYS a sequence of events. And there's one thing nearly all those theoretical physicists DO agree on: time is relative from the point of view of the observer. So my suggestion would be reductionism: break the sequence of events down into smaller and smaller chunks and ultimately there's no paradox. Yes, it's possible one party is retroactively "deleted" from the timeline. Whereupon, for the frame of reference of their opponent, they never fired. They ceased before it could become a conflict. And since their opponent, too is submerged in the same stream of time, they, perforce, would be unable to perceive any sort of potential paradox. Or, take the string theory approach and assuming every choice bifurcates into every possible choice, and obviate the potential for it entirely. Personally, I think the mechanic by which the characters could have perceived an event taking place that was subsequently balefire'd out of existence yet they still remember it would/could/*should* be harder to explain than the nitty gritty of the temporal torpedo... but maybe that's just me. [Answer] The flight time of the weapon is instantaneous, in effect. It's just as if the two ships were literally touching nose-to-nose. It is asked about what happens if "the ships fired at the same time." Same thing happens as would happen were they nose to nose, I suppose. Either "the same time" really means plus or minus a few seconds or milliseconds, and one ship is destroyed before it can fire, or, if it is truly instantaneous, it depends on whether the weapons are such that they can complete firing while being destroyed. [Answer] The first major problem is (as defined in your question) that even assuming a time traveling weapon was possible the observer in control of it cannot! The weapon can be fired at a set of coordinates but there exists no targeting system which lets the user observe the past to detect approaching threats! This means that in terms of space combat any two ships randomly encountering each other are limited to the moment one or other vessel first detects it's opponent via the same old boring sensors like radar or thermal imaging etc that everyone else uses in space combat. You literally can't know in advance using your 'time scope' (because you don't have one) that your enemy will appear at co-ordinates XYZ in precisely 10 minutes time. That means your limited to using conventional sensors to locate and target your opponents and all such sensors have margins for error. So the longer the range the less accurate your targeting is going to be. Which means you precisely the same dilemma you have with conventional weapons. You can either fire at long range with a high probability of missing the target or wait till your targeting solution becomes better. The second limitation is related to the first in that time equals distance in this context. The farther back in time you attempt to aim the farther away in space the target will be which again means the less accurate your weapon becomes. So its not like you can 'see' and enemy and then switch the weapon to '3 years ago' aim at the space dock where that ship was being built and blow it up before its even launched! And since range increases the farther back in time you try to fire inaccuracy must also. (Except in some particularity rare or unusual combinations e.g. 2 ships traveling close together for years on time who suddenly decide to start shooting 'time bombs' at each other.) ]
[Question] [ I am looking for a plausible explanation as to why approximately every few decades something happens that destroys surface electronics and then continues for several years. Ideally it would be unpredictable. I've looked at handwavium <https://worldbuilding.stackexchange.com/a/217778/94879>. I think this would not work for me as I want something irregular and random, whereas the handwavium suggestion would be regular and predictable. I've also read about the Carrington Event, and I could do something like that however, I think these would not be strong enough to wipe out all electronics. What could be unpredictable like geomagnetic storms, but powerful enough to destroy electronics but not living things? [Answer] two natural, one artificial.. Solar EM flares Your sun has quite powerful EM hickups. It is about to go supernova. It could be 60 years, or 60.000 years, they can't be accurately predicted. But there's a supernova coming soon, so any settling scenario would be short. Geomagnetism Your planet has tectonic activity and a layer of magnetic substrate in its crust. When an earthquake occurs, induction currents will cause EM pulses and your radio gets fried. Unintended side effect of propulsion system experiments Your settlers are hobbying with new spacecraft technology. They don't mind rules and regulations, so they messed up their Alcubierre prototype. It causes EMP's now, these seem to bounce around in space time, everywhere around the planet and on various points in time. Every EMP event is an echo of a previous instance, causing damage in electronic equipment. The echo of the event will slowly fade out in space time, eventually, but that will take 10000 years. [Answer] # Surprise brine I was born in the city with the 2nd saltiest air on Earth (just learned it is actually the 1st). Electronics, appliances and even cars last shorter there because of the immoral amount of sodium chloride in water vapor. Stuff simply corrodes as if it took a dip in the sea for a fraction of a second everyday. By the way humidity is usually 50%+ throughout the year. Air conditioning in server rooms is not meant to cool down computers, but rather to keep air dry so it is salt free. In your world, some unexplained phenomena may randomly fill the air with salty vapour too. Maybe volcanic eruptions. This will harm electronics for a while, and then things get back to normal for years or decades. The fun part is never knowing when the next eruption will occur. [Answer] A [Carrington Event](https://www.nasaspaceflight.com/2020/08/carrington-event-warning/) would definitely impact the power lines and likely cause widespread power outages, and perhaps even failure of the US grid power for a substantial period of time. In addition to the power outage and other impacts on infrastructure, there would be voltage transients that could be hard to handle. A lot of well designed electronics have some type of protection, but not all. In some cases, electrostatic discharge would also cause device failures. Such an event would impact satellites, perhaps knocking them some out, but maybe not as obvious is that the ionosphere will be disturbed and radio communications will be impacted. Scintillations in the ionosphere will make GPS less precise. Airlines that fly over the poles actually get space weather reports to help better understand radio and navigation problems caused by space weather. So something like a Carrington event would cause problems, but probably wipe out everything. Radiation on the other hand, assuming it is not too detrimental to your people, plants etc. Is something that can cause electronics reliability problems. A lot of modern electronics are based on field effect transistors or CMOS device, and they are essentially electrostatic devices where a small voltage on the "gate" will allow the current to flow from the "source" to the "drain". If there is some extra charge somewhere near the gate, the amount of voltage to control the device changes. So when a particle goes though the semiconductor it knocks electrons off the atoms leaving an ionization trail. These extra electrons if near the gate can cause the device to fail. Other things can happen too like blowing a hole in the gate, or creating defects by knocking atoms around etc. There are a bunch of people who work on radiation hardened electronics to try to get around these types of problems. A lot of the failures in electronics from radiation are from cosmic rays, or from particles from the sun. The ones from cosmic rays are interesting since they can come from beyond the solar system, and there are cosmic ray showers of energetic particles when a cosmic ray hits the atmosphere. So on the surface of the planet, I suppose you could have a couple of choices. Some galactic source pulses every decade or so and zaps your electronics. Or perhaps there is flare where in addition to the geomagnetic induction of voltage on the wires, there is enough radiation that makes it through the protective aspects of the earths magnetic field. Or perhaps you could hand wave and have the magnetic field have a glitch or flip directions and the radiation zaps the electronics. Maybe the people, plants and animals have evolved to have to had some tolerance for the radiation, or along with your electronics having problems, there is an increased risk for cancer. For electronics, especially computation pretty much every thing has to work perfectly, for people and animals, people get x-rays, sunburns, or live at high altitudes, smoke etc. so in someways are more tolerant of radiation. Instead of Silicon and other types of semiconductor transistors, you can have vacuum tubes, or microfluidic devices that are more tolerant of radiation. But building a computer, or some other types of electronic devices would be a lot harder, and often not very small. Edited to add link to NASA Article on the [Carrington Event of 1859](https://www.nasaspaceflight.com/2020/08/carrington-event-warning/), the massive solar storm that allowed people to see Aurora Borealis as far south as the Caribbean and allowed telegraph operators in Boston to operate the systems with the batteries unplugged. (It also caused fires at numerous telegraph stations. It is expected that such an event would cause major disruptions if it occurred today. [Answer] [Monoculture](https://en.wikipedia.org/wiki/Monoculture) and anti-material bacteria. The settlers made sure that their gadgetry uses interchangeable standard parts. Their plans for industrial development included either one factory, or two identical ones. They produce something like an [Arduino](https://en.wikipedia.org/wiki/Arduino) that ends up controlling industrial power plants, cars, consumer electronics, etc. Then a local microorganism mutates to eat the material of the standard circuit board. So all microcontrollers die, including those running the microchip [fabs](https://en.wikipedia.org/wiki/Semiconductor_fabrication_plant). The village blacksmiths will be able to draw wire and wind generators and electric motors. Perhaps someone manages to produce lightbulbs without the use of microchips. But the electronics must be re-invented from scratch. This re-invention is problematic because of low population numbers. It takes many millions of people if a society is to have the surplus for something like the [Bell Labs](https://en.wikipedia.org/wiki/Bell_Labs). [Answer] 1. Total, rapid collapse or inversion of the planet's magnetic field. Earth's magnetic field inverts over long periods of time and IIRC varies in strength. On your planet, it loses its strength suddenly, exposing electronics to solar radiation for an indefinite period of time. As I understand it, that's totally plausible for many planets with magnetic fields generated by liquid metal layers. There is even some speculation about how stable Earth's is. 2. Phase changes of magnetic core materials: Iron loses most of its magnetism above the Curie temperature. If you wanted to go for something less realistic but more fun, you could have a planet where the whole planet is made of iron oxide or some compound that is a far better magnet when solid than melted, and the temperature beneath the surface is erratic as hell, resulting in underground magnets the size of mountains forming and melting as underground temperatures vary. Make it out of the same material as neodymium magnets for more fun. Whether the electronics get fried by solar storms that are no longer impeded by a geomagnetic field, or mountain sized neodymium magnets appearing next door is up to you. [Answer] Metal Cicadas [![enter image description here](https://i.stack.imgur.com/aVOTA.jpg)](https://i.stack.imgur.com/aVOTA.jpg) The metal cicadas spend most of their lives underground. Every few years they respond to changes in the planets magnetic field and metamorphose into adults. They climb to the surface and are drawn to electromagnetically active areas. They clog powerlines, generators, and antennaes. This process continues for a few years, until all the surface electronics are destroyed and the next generation of cicadas stays underground. [Answer] Luddites [![luddites](https://i.stack.imgur.com/UBLI2.jpg)](https://i.stack.imgur.com/UBLI2.jpg) <https://www.cbsnews.com/news/almanac-the-luddites/> The Luddites were mill workers who in 1811 began a campaign to smash mill machinery. It evolved into an antimachinery movement, characterized by breaking said machines. The term "Luddites" today refers to persons who fear and hate technological innovation, and are prone to destroy such innovations. On your world there exists this movement. Perhaps once a generation these folks go on an antitechnology rampage. [Answer] #### Comet tails Every few decades a comets procession passes close to the planet, between the planet and its star. The tails of all the comets wrap the planet, they are a mix of dust and gases. The atmosphere of the planet is windy and humid, colliding with the dust and the condensed vapour coming from the comets a lot of particles get a static charge. A storm of lightnings discharges on the planet surface. [Answer] * The "Stars align" to produce an electromagnetic effect, planets in the system with periodic orbits that only every so often line up well enough to channel Solar wind, or magnetic interference sent from a distant gamma ray enough to kill electronics but not living being. Not all planets are involved each time, so the unpredictability would come from different numbers of orbits lining up at different times. * An old weapon system from ancient civilizations is still partially operational, charging it's energy banks and when filled, expelling a system wide EMP, over time this energy bank is taking longer and longer to charge, or the trigger mechanism is disfunctional. * Experimentation and war driven civilizations may periodically send each other and themselves back to the stone-age. By then, most records are kept digitally, paper and other documents not longer the norm, causing a tech revert to come also with a loss of documentation and history when technology no longer works. * Overseer visit, be it known or unknown to the story's citizens, Powerful cosmic custodials sees that the planet is not ready for the powers it is beginning to wield, and decide for the better of the planet (rather than have a mass extinction) to revert technology via Electromagnetic wave to essentially give the planet another chance. * Geological episode, volcanoes can often be accompanied by lightning, on a larger scale, the eruption of a tightly confined volcano with enough charged material could produce an EMP wave of sorts. * Religious revolt. Perhaps a smaller accident occurred, or paranoia is generated as a means to an end, that being the destruction of all technology. There may be hangers on, but over time the law is changed to remove tech where found until the original issue is forgotten and years later a new tech revolution begins before another cause destroys it. ]
[Question] [ The inhabitants of my Earth similar world have a preindustrial society, but have managed to create airships. These use plywood, hot air and relatively thick material for the envelope. But these inefficient craft are fully practical thanks to the recent discovery of Heavenium which can reduce the weight of these airships by up to 90%. How can the inhabitants of my world use Heavenium to propel these airships forward? And are there any obvious inconsistencies with Heavenium? Heavenium is a light weight red colored substance found in some rare mineral veins. It is inert and has defied all analysis. When it absorbs heat it reduces the effect of gravity in its vicinity. After sufficient heating a large quantity of Heavenium can reduce the effect of gravity in its vicinity by up to 90%. The effect rapidly decays with distance (inverse square law) so that things more than around 10m away from it feel little effect. The gravity reduction effect lasts for many days after which the Heavenium needs to be strongly heated again. If used to transfer potential energy into objects by moving them higher the Heavenium become discharged. The amount of discharge is directly related to the amount potential energy transferred (energy is conserved). [Answer] ## Heavenium engine Take an ordinary water wheel. No water. Put a piece of heavenium under one side of the wheel. The side above the heavenium will become lighter, and the wheel will rotate. Use this heavenium engine to power propellers. Problem solved. Note that the same principle can be used to power lathes, mills, mechanican looms, spinning jennies, and so on. Heavenium engines will power a fervent industrial revolution. After the discovery of heavenium, your society won't remain preindustrial for long. ``` This This half half is is heavy light _____ / \ / \ \| <> \| \ / \_____/ ^^^^^ heavenium ``` [Answer] If you lower the heavenium underneath your gondola after you reach altitude you will start to sink and can then glide your airship if it has wings. Then raise the heavenium again to gain bouyancy and you will rise again. You can change your wings such that you glide as you rise and glide as you fall. Keep doing this and you will move forward till the heat energy is converted into kinetic energy in the atmosphere and you will have travelled. [Answer] Heavenium negates a force (the effects of gravity) but doesn't generate any thrust itself and so cannot be used for propulsion. The 10m radius of effect might be difficult to work with depending on the dimensions and mass distribution of your airship and the amount needed to have the effect. For example, something the size of the Graf Zeppelin would be 236m and 33m high and would need chunks of Heavenium distributed in a 10m grid across the airframe. These chunks would vary in size depending on the mass distribution; lighter parts of the airship would only need smaller chunks. One would need to explain how these chunks in various awkward places in the airframe are accessed so they can be heated. (Looping back to propulsion briefly, it's actually a good thing that Heavenium does not generate thrust or the locations in the airframe would need to be load-bearing too.) As for conservation of energy, it would be worth doing a quick calculation using the formula for potential energy stored by gravity and the mass of your airship to see how much energy needs to be stored. This will determine how much heat and how much time it would take to charge up the Heavenium; might take a couple of days or even a week in a kiln or something. Also, you say "If used to transfer potential energy into objects by moving them higher the Heavenium become discharged." but does the energy come back when going back down? If not, either the energy is being emitted somewhere or conservation of energy isn't true. [Answer] There are [autonomous underwater craft](https://en.wikipedia.org/wiki/Underwater_glider) which move forward by simply making themselves denser or less dense than water (by compressing or expanding an airbag). This allows them to glide, under either weight or buoyancy, with "lift" converted to forward motion by the airfoil shape of their body. If you're willing to abandon the traditional cigar shaped envelope, you can certainly do the same in the sky with an airship, using Heavenium, by moving it forward or aft to adjust the centre of buoyancy, and angle the nose up to climb, or down to dive. It might look a bit like ~~a huge flying butt~~ [the Airlander, by Hybrid Air Vehicles.](https://www.hybridairvehicles.com/) (image : Conde Nast Traveler) [![enter image description here](https://i.stack.imgur.com/C0gJ5.jpg)](https://i.stack.imgur.com/C0gJ5.jpg) An alternative might copy the blended wing/body concept of the AirbusZeroE, but perhaps without the redundant wingtips. Here the point of the wing isn't to provide lift : there's no need; but to provide forward motion. You may get a lift/drag of 3 or 4 for the ~~flying butt~~Airlander giving 1 km forward per 250m climbed; the blended wing may be closer to 8 or 10, giving 1km for 100 or 125m climbed. [![enter image description here](https://i.stack.imgur.com/YRspQ.jpg)](https://i.stack.imgur.com/YRspQ.jpg) [Answer] Quick reality check: The Gravitational potential energy is locally ``` U = mgh ``` This is for example valid for a stationary object in a stable gravity field. `m` is the mass, `g` is the local gravity, `h` is the height. (Height is relative to an arbitrary point, so that this is mostly useful for measuring differences in potential energy) When you apply heat to your heavenium, `g` decreases for objects around it. This decreases the value of `U`, resulting in a loss of potential energy. The energy must be conserved, as you mentioned. Where does the potential energy go? [Answer] ## Heavenium Jet Engine The theory of this engine is based in the Archemidean principles, and while it would first be used by civil engineers for fountains and other waterworks) and shipwrights (of seas) it could eventually be adapted for airships. The principle behind it is simple - a still fluid stays still because every other bit of fluid above and to the sides of it presses it down with the same force of gravity. But what would happen if we put a vertical pipe of heavenium into that fluid? The fluid inside the pipe would get much lighter and the surrounding fluid would force it upwards, just like a piece of cork under water. And it would draw with it a new amount of fluid, which would get lighter and be forced upwards in a constant stream. This upwards motion of fluid alone would be godsend for civil engineering - a pump with no moving parts! But that is not all - the fluid that has started flowing still has some momentum to it that can be redirected. Just put a bend in a pipe and it will now flow out sideways propelling the engine and anything that is attached to it sideways. [![Heavenium Jet Engine](https://i.stack.imgur.com/O1xIR.png)](https://i.stack.imgur.com/O1xIR.png) Air is just a form of fluid - and as boat can float on a water - so can balloon on the air. And in the same way the heavier water would force lighter water upwards - so would air. Of course there are differences. For one - air is about thousand times less dense than water which means that it will propel the ship with much less force. On the plus side, that means that heavenium will need to be recharged less. Also air unlike water can compress, which means that to get a good flow you instead of a simple pipe you would need a much wider funnel in the intake. Pros: * No moving parts * Simple construction * Easily controlled (rudder + lid or just mount the whole thing on a swivel) * Useful in other applications (lower cost and quicker R&D) Cons: * Very low thrust in the air * Difficult to recharge Possible improvements (possibly incompatible): * Replace the Heveanium funnel with ordinary funnel + Heveanium mesh on the intake for better pressure profile and efficiency * Place re-loadable heaveanium bunker above the funnel for easier refuelling * Add access and fittings for in-place recharging - e.g. burning a breazier of coal right below the funnel [Answer] 1. I don't see any obvious logical inconsistencies with the concept of heavenium itself. It's like hydrogen only better at lifting: if it's a solid, it can easily be attached to the airship, or anything else people wish to lift up. 2. Given your description of heavenium as a countergravitational substance, I don't see how it can be used for lateral movement. I think your aerogators will still need some kind of motive force, a fan of some kind, or sails, to actually propel their ships forward. [Answer] Heavenium violates the Second Law of Thermodynamics. You don't need fuel. ## What? > > The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible. Isolated systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy. > > > […] In all processes that occur, including spontaneous processes, the total entropy of the system and its surroundings increases and the process is irreversible in the thermodynamic sense. The increase in entropy accounts for the irreversibility of natural processes, and the asymmetry between future and past. […] > > > […] Its first formulation is credited to the French scientist Sadi Carnot, who in 1824 showed that there is an upper limit to the efficiency of conversion of heat to work in a heat engine. This aspect of the second law is often named after Carnot. — [Wikipedia](https://en.wikipedia.org/w/index.php?title=Second_law_of_thermodynamics&oldid=991847499), used under [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/) > > > ## Why? All processes that require heat are either entropic in nature (e.g. cooking), or actually require a temperature difference (e.g. Sterling engines, solar panels). All natural processes that extract useful energy (aka do work) from a temperature difference also reduce that temperature difference. In short: without access to sunlight and the vacuum of space, you'll run out of usable energy sooner or later. Heavenium, however, works on absolute temperature, like entropic processes, but provides useful work, which you can normally only get from a temperature gradient. It's a negentropy source. This stuff's worth more than the Sun. ## How? There are countless ways of making use of this, but I'll start with the simplest to explain. ### Heat pump in a box Make a pulley. One end of the pulley should be a box containing some fancy technology and some Heavenium (I'll get to that in a sec); the other should be weighted so that it goes up when the Heavenium is “off” and down when the Heavenium is “on”. Attach the pulley to a really tall tower. In the box, wind up some clockwork, and attach it to a heat pump. Set the heat pump so that it'll warm up a compartment containing Heavenium and cool down a compartment containing hot water, then start it going and shut the box. The Heavenium box will go up. Use some of this energy to do work (e.g. winding up some more clockwork). Eventually your clockwork will run out, or your heat pump won't be powerful enough to heat the Heavenium to the critical threshold any more, and the Heavenium will run out of magical lifting ability; you know when this will happen in advance, thanks to your calculations, so you can switch to generating energy from the pulley going the other way. If you use a Sterling engine to recover the energy from the temperature gradient the heat pump made, you will have: * Cold water, and a cold box in general; and * More energy stored in clockwork / used to do useful work than you started with. With a sufficiently-powerful heat pump, you could start with regular old ambient-temperature water, cool it down, and generate energy for useful work. Of course, eventually, this energy would run out; friction and other losses would see it slowly lost to heat. But you can extract work from heat. Your airship does not need fuel. ### Heavenium engine Okay, so maybe building a massive tower in the middle of your airship isn't actually all that practical. You need something more [engine-like](https://worldbuilding.stackexchange.com/a/191896/11665). Take a heavy flywheel, and put it vertically over a well-insulated Heavenium-containing oven (so that the rising side is lighter); insulation reduces the maximum power your heat pump system needs to have to get the Heavenium hot enough. (Frictional losses aren't all that important because a Heavenium engine uses heat as fuel – I still can't get over how overpowered this is!) Fuel this oven with a powerful heat pump (or chain of heat pumps) powered by the Heavenium engine. The energy will eventually get back to the heat pump no matter what you do, but you can speed it along by sticking the “cool” end(s) of the heat pump on whatever's generating most of the frictional losses. Now simply heat up the oven to the critical temperature, spin the engine a bit to get it started, stick a fan on the end and you're away! ## When? Heat engines have been known since antiquity. The first refrigerator (requiring pretty good heat pumps) predates the industrial revolution by over 75 years. While this technology might not be immediately apparent, since the Second Law of Thermodynamics hadn't been invented yet, anyone who understood fridges and had heard of Heavenium would probably be able to figure it out, and it wouldn't take much longer to develop heat pumps good enough that this would be viable. Unless, of course, you need to get the Heavenium really hot. Then this is right out. [Answer] I can see a problem with Heavenium - at best it only reduces mass to 90% of normal. What this means is a 20 ton airship will plummet out of the sky just as quickly as a 2 ton brick. To overcome this, you suggested hot air to provide lift. So your airship will need to carry a source of heat aloft, which will also require its own fuel. BUT ... all this adds even more weight to your airship. At first, one would imagine having a crew shovelling wood or coal into a fire which heats the Heavenium with the waste heat being used to lift the now lighter airship. You could have a turbine in your chimney, turning a propeller through a gear mechanism to provide forward thrust. So while the Heavenium itself is not providing thrust, the thrust is generated as a byproduct of the means to lift the airship and heat the Heavenium. Later developments could have more efficient heat sources - gasoline, electricity, nuclear power; jet engines to provide thrust and drive turbines; helium to provide lift (not hydrogen, as it doesn't behave well with flames!); lightweight metals replacing plywood; and so on. As your airships get larger, you could pump liquified Heavenium around your airship (if the stuff ever melts?), or just pump the heat around your airship heating lumps of Heavenium strategically placed around the structure. However, there is going to be some tricky balancing between the weight of your airship (structure, fuel, cargo, passengers, etc), the weight reduction properties of Heavenium, the amount of lift provided by hot air/helium, and the air density as it varies with altitude/weather. [Answer] ## Heavenium heat engine Take a Bhāskara's wheel filled with half Heavenium, half water. Put heat in one rotating side, left other side to lose heat to air. You will have rotacional force generated in place. A little coal could make you very far. See [Renewable Energy from Evaporating Water](https://www.youtube.com/watch?v=Vj2kuZm-aCA) for inspiration. Bonus: You can use the residual heat to keep the lifting Heavenium warm. [Answer] There are several subtle implications in your "Heavenium": * how efficient is the heat conversion in potential energy (i.e.: how fast will it discharge when "pushing up")? If efficiency is comparable with steam engines then it's mostly useless as "engine", while retaining it's full power as "keep height" device. * "perpetual motion spinning engines" as described in other need to be heavy to generate a sizable amount of energy and thus are a bit useless for aircraft motion. * It's unclear how do you plan to regulate ascent/descent of your aircraft and I assume it is "normal" Archimedes law (corrected with gravity, and thus weight, reduction). * If the above it's true then "airships" need to be huge to leverage on a certain amount of air weight. This, incidentally, means they will have a large cross-surface winds will act on. * What happens, exactly, when Heavenium is "discharged"? I will assume it gradually looses it's "power" and thus the nominal "90% reduction" will steadily and gradually decrease as the airship rises up. * If you want to be "creative" you can make your airship large and flattish and "power" it with two (or more) Heavenium capsules: one near "forward end" and the other near "aft end". + start with airship at equilibrium with 80% Heavenium charge (~70% gravity reduction). + heat up forward capsule and ship will start raising "nose first". This will cause a forward drag because of ship geometry. + heat aft capsule "just enough" to maintain it's power as ship raises. + stop heating forward capsule; this will cause a brief "overshoot" (mass is not affected, so airship has a rather large inertia) and then it will start falling, again "nose first" (if aft crew did their job right) and thus, again, producing a forward drag. + rinse and repeat: you ll'have a big flat "whale" moving slowly and steadily (in calm air). * Heavenium (as described) cannot be used directly to produce horizontal (orthogonal to gravity force) drag. * You can't either use any kind of "sails" because those rely on keel drag, which you don't have. ]
[Question] [ As a background, a team of seven astronauts embark on a journey through space. Their aim is to find the source of radio waves that have been attributed to communication from a distant planet (referring to an exoplanet). The astronauts reach their destination in six months in a powerful space ship, with "faster than light" traveling capability (through warping of space). Upon arrival, they find no sign of life. Disappointed, they bein their return journey, but due to some accidents on the planet, run out of their food supply. --- This is where I am stuck: > > How do they find food ? > > > It can be assumed that they have enough water (through a recycling module) and their ship has capabilities to very efficiently convert the star's light energy to electricity. Assuming they can traverse much of space but have a limited food supply (let's say the recycling module's organic matter recycling part broke), how do they successfully return? [Answer] Water and electricity is not enough to produce food. Sure, lack of water kills way faster than lack of food, but if they have no means of producing food, they don't have many options. Space apart it sounds like the history of the [Essex](https://en.wikipedia.org/wiki/Essex_(whaleship)) > > Essex was an American whaler from Nantucket, Massachusetts, which was launched in 1799. In 1820, while at sea in the southern Pacific Ocean under the command of Captain George Pollard Jr., she was attacked and sunk by a sperm whale. Stranded thousands of miles from the coast of South America with little food and water, the 20-man crew was forced to make for land in the ship's surviving whaleboats. > > > > > The men suffered severe dehydration, starvation, and exposure on the open ocean, and the survivors eventually resorted to eating the bodies of the crewmen who had died. When that proved insufficient, members of the crew drew lots to determine whom they would sacrifice so that the others could live. A total of seven crew members were cannibalized before the last of the eight survivors were rescued, more than three months after the sinking of the Essex. > > > Apparently, based on the numbers above, in 3 months half of the survivors were cannibalized. This would mean that your crew could maybe have one or two survivors reaching back home. [Answer] It definitely sets a tone that you may or may not want in your story, but to quote an Orc - "What about their legs? They don't need those". That's 14 legs that are made of meat! Given they're in space, they're entirely capable of manoeuvring around using only their arms. If the ship has an artificial gravity system, it could be turned off to enable the poor volunteer to move around. They'll lose the ability to kick off surfaces, and have a significant amount of trauma but they'll not die (assuming there's a medic/medbay on board to perform the butchery). However, that is pretty grim and doesn't have a place in many stories. [Answer] If there is no life on the planet then maybe they track down an earlier failed mission. A derelict spacecraft and its stock of unused provisions is an excellent source of story potential. If the previous mission is far enough off their path, the crew might need to decide that one or more people would have to be left behind to preserve supplies Of course for a one year round trip just carrying that much food would be much easier and safer then trying to recycle solid waste and organic matter back into food. If their source of water was destroyed instead of their food, then they could look for icy comets and asteroids, even a single small asteroid might hold decades of water. [Answer] The ship is edible I refer you to the Japanese game show Candy or Not. Contestants have to guess whether incredibly genuine-looking objects are edible or real. There are plenty of videos to be found. [![enter image description here](https://i.stack.imgur.com/W9OmQ.png)](https://i.stack.imgur.com/W9OmQ.png) They can start by eating the less vital equipment maybe tables, chairs and entertainment facilities. As long as the hull, motors and navigational equipment are non-edible, they can return, even though in straitened circumstances. In this future age, it is quite feasible to make a durable plastic-like substance which can also provide nutrition when broken down by saliva and stomach juices. [Answer] The scenario, if I may summarize it from the OP in my own words: * a closed system (the spaceship) that needs to remain closed for 6 months. * 7 people inside that need to eat to stay alive for that period. * some food cycle system did exist in the ship, but some part is now broken. * thus a severely diminished food supply that will not sustain the lives of the 7 for that duration - but not completely zero. I'm also going to assume that: * no resupply from the target planet was possible, either through lifelessness or incompatibility of native organic matter with the Earth-originated ecology. * the spaceship can't make any intermediate stops for resupply either (myriad of reasons possible). * the ship has some form of artificial gravity, as that will make some of the processes much easier and a known quantity (already done on Earth). What I propose is alluded to in some other answers and comments, but I'm going to flesh it out in practical terms: # Do nutrient recycling as it is done on Earth by natural processes (enhanced by human intervention, as needed). 1. Time: What people often underestimate regarding growing plant crops is the time that is needed. It's not simple sticking some seeds in soil and watering them, and voil√† the next day (or month) a fully-developed, nutritious potato has appeared. Same goes for breaking down biomass until it is suitable as a growing medium that provides nutrition to the plants that grow in it. You need to provide some means for the initially needed time to ramp up the system - perhaps by having some remaining foodstuffs, strictly rationed; perhaps by having the crew fast (30-40 days is probably realistic without adverse long-term health effects). a) I'm not sure how you will get very hungry humans to abstain from "touching" the not fully grown plants. The crop needs time to develop to full potential where it can feed the entire crew. If I were to write such a story, maybe I'd have the expert/hobby botanist on the crew locking/barricading him/herself into the agri section (with some rations) were s/he gets the process going, only coming out once food supply has been guaranteed. At least there is enough plot potential for an entire book right there - tough love, hard choices between two suboptimal options, isolation, conflict, power dynamics and politics, human nature, and all that. 2. Converting biomass to growing medium can be accomplished in a myriad of ways. a) Lasagna containers: People I know build "lasagna beds" in plastic tote cases, old truck tires, or similar containers, which can be done in small courtyards or even in sunny indoor places. Recommended depth around 40 cm / 16 inch, and would be done in a continuous fashion as biomass becomes available and new crops need to be established. Read up on the lasagna method, but it entails alternating layers of "green" (nitrogen rich) and "brown" (carbon rich) biomass, which triggers the composting process. Paper and cardboard generally count under "browns". Can be enhanced with some soil, compost (from previous batches), minerals. Can be planted immediately if the top layer is an appropriate compost/soil mixture, by the time the roots have reached the lower levels, they should be well underway to compost state. Needs sufficient space for the composting process to develop (depth x width x length) so a tote-size case is probably minimum per iteration. b) One can also make compost outright. The speediest compost piles are "warm piles", i.e. microbe-rich (more on that later) which are given optimal circumstances to do the decomposition at optimal rate and generate quite some heat in the process. You'd need a space of dimensions about 1 m / 3.5 ft min to 1.5 m / 5 ft max, to contain the composting material, and some means to ventilate it (blowing air through it mechanically should work). "Dimension" means length, width, height and/or diameter, as applicable - it's a flexible guideline. Again "greens" and "browns", mixed well, in a ratio of around 1:1 to 1:2, and quite a lot of moisture (water) - wet but not soggy or dripping. One or two "turn-overs" (remixing the pile) are often needed to keep the decomposition going, so you'd (temporarily) need that extra space to keep the material. Let's say you can have growing medium ready in about 6 weeks. Composters are usually discouraged from putting anything other than plant material in it, but "warm" compost piles as above have been known to decompose various dairy products, meat (raw and cooked), cooked leftovers, oily foods, hair, bones, blood, and even (small) animal carcasses and human waste products (urine and excrement). Warm piles have been known to ignite in rare cases, which is usually prevented by not going too big (or monitoring them like a baby). c) Another way that is used in many kitchens (including small apartments) to handle biomass is the Bokashi method. This can also handle all of the above non-plant materials. A filled container, mixed with the bokashi "bran", is closed air-tight for 2 weeks to allow an anaerobic fermentation process to complete, which is performed by various microbes with which the "bran" was inoculated. Do note however that this is not a complete process, and would require finishing-off by one of the other methods - the benefit however is that it preprocessed some biomass that the other methods would not like, or take much longer with, so the recycling is sped up. d) Earthworms are marvelous little creatures that in 24 hours can turn biomass of half their body weight to the absolute best compost (often wonderingly called "black gold"). However, they work best on half-rotted material (compost pile or bokashi thus works well as a preprocess step). 3. Once you've got your biomass nutrients turned into growth medium in this way, I think you're past the biggest obstacle since this nutrient and microbe-rich material grows plants that are usually disease free and producing abundantly (provided the right minerals and trace elements are present). Since it is so nutrient-rich, it lends itself to higher plant densities or smaller growing containers, which may be appropriate in a space where space is at a premium. Of course, this assumes that the necessary seeds/seedlings/cloneable plant material is on board in the first place... a) The earthworms also produce "castings", a mass of little roundish particles that some have converted hydroponics systems to use instead of the usual growing salts - see [vermiponics](https://en.wikipedia.org/wiki/Vermiponics). Otherwise they could just be added to the growing medium. You would probably still get such medium out of your worm farms (and/or other systems) in addition to the castings. 4. Apart from eating plants, I have heard earthworms are also considered a good source of complete proteins and a delicacy in some places - prepared in the right way. (No first-hand knowledge here, (un)fortunately...) Guesstimates are that you can keep not more than 5 kg of Eisenia fetida worms per 1 m¬≤ (about 1 pound per sq ft). You'll have to research reproduction rate yourself if you want to go this route, but they can be quite good breeders under the right circumstances. # Some problems and other notes 1. The above processes do depend on microbes (viruses, bacteria, yeasts; and optionally but preferably also nematodes, worms, insects) to work at all. They occur on Earth simply in the environment, but what about on a spaceship that's presumably sterilized? Although, the International Space Station has [shown that it is quite hard to keep all microbes out](https://www.forbes.com/sites/linhanhcat/2019/04/17/microbes-international-space-station/). All living organisms on Earth live in symbiosis and we humans probably carry more microbes than our own cells around with us. So some mix of luck, microbiology knowledge, accidentally or deliberately brought-along microbiomes would be needed to get the right critters for the process. Maybe have bokashi be a part of the original waste conversion process, some on-board experiments, a smuggled-in pot plant, fecal swabs of the whole crew by the microbiologist.... 2. Same goes for earthworms. Why would there be [Eisenia fetida](https://en.wikipedia.org/wiki/Eisenia_fetida) on board? Some reason to be thought of. 3. Same goes for having viable (reproducable) foodstuff plant material on board. Maybe from an existing food production facility (hidroponics?), maybe experiments, supplies for a colony of sorts, etc. 4. Human waste products (urine and excrement) are a nutrient resource that should not go to waste in a closed system like this spaceship. Warm compost piles and bokashi fermentation both have the potential to neutralize harmful pathogens and help return the material to the food chain. It has already been done on Earth. If you need more background, I strongly recommend [The Humanure Handbook](http://humanurehandbook.com/) as a starting point, in addition to websearch for the right terms. This book also provides a wealth of information about warm compost piles and microbial life, even if one does not plan to bring any animal dung near it. Although, 3-4 months (6 months minus the old rations/fasting rampup period) might not deplete nutrients in the cycle enough to matter. So to make it more interesting, the travel time could be extended... [Answer] For a voyage of >6 months (each way?) I might actually expect that the ship is designed to be able to grow food; otherwise that's a lot of wasted weight, an extra mechanism for waste disposal, and the risk of food loss that you're explicitly worried about here. In the general case life on a spaceship (or anywhere) is sustainable if energy-in is equal to energy-out, and there is a closed nutrient cycle. The energy-balance hasn't changed so you should be good on that front, solar lamps to grow plants seem pretty reasonable in space if you don't have better tech. A big food loss will disrupt the nutrient cycle; but given all the humans are currently alive there are definitely enough total nutrients remaining, even if everything is running a bit closer to the wire than the crew might hope for. If the crew is particularly worried, they may have the grim task of bringing back corpses from the site of the accident for use as fertiliser. In the very worst case you might need to make some corpses for fertiliser to kick start the process, but that might not need to be very many of the crew. [Answer] ## I have several ideas, though all of the hinge on mission and spacecraft design Mainly, since the vessel has a warp drive, we don't really have to care as much about the rocket equation. Meaning that bringing more elaborate equipment is justifiable. Furthermore I'm going to assume that thed setting has some near and far future technologies. Disregard options that do not fit your setting. 1. Do you want to eat canned food for a year? Can you imagine the effects that would have on morale? Yes? Good that this is an easy problem to solve. Try hydroponics and vat grown meat. Both are technologies that are rapidly maturing today and bringing a farming module on such a mission is quite justifiable. Maybe the rations were just the carbon component of the meals and now the hydrocarbons need to be expanded/repaired. Alternatively you could feed everyone out of a yeast and alge based agriculture. Aquaculture can also be done in some of the inner water tanks. Just have the mission planners be a bit more creative about feeding everyone. 2. Build some sort of "farming". Let's assume that Tey have a lot of blueprints, really good design AI and decent, 3d printer based, manufacturing capabilities. Even if they don't have lab meat growing capabilities to bed in with, these highly skilled individuals (probability there is at least one biologist) and the vast databases of their vessel should be capable of setting such a system up. Then you would only need some blood and you can start growing meat. Farming labrats or alge used in the recycling systems you'd work as well. 3. Cannibalism, but we'll planned and organised. Amputations shouldn't be too hard in a property equipped medical bay. Calculate how much food (arms and legs) is needed to feed none or one or two people, depending on what's the minimum crew, for 6 months. Then cut of what you need, put everyone who's not required into an artifical coma to reduce food consumption and set up the medbays machines and the shops robots to feed the astronauts. They should all come home, all be it malnourished and a few limbs short. 4. If cryonics exists in your setting, they are a great option here. Even if they exist, there are good reasons for why they aren't standard procedure for space travel. Maybe there are religious or cultural biases against litteraly dying and beeing conserved in a state where reanimation of the frozen corpse (not wakeing up the sleeper, you are certifiably dead when in cryostasis) is possible. Or there is an significant failure rate, something like 20% don't come back and 40% have brain damage. If it is possible, construct freezers and medical equipment, mix up the antidepressants that will prevent brain damage and decapitate the crewmen going into cryostasis. You only need the brain with the head anyway. Might as well use the bodies to feed the guy who will fly the vessel back. The others might have to wait a hundred years longer, until unfreezing has become saver, but they'll live (again). 5. Use the medical printer or synthetiser. If the technology is sufficiently advanced the medbay should have a way to grow replacement organs. Just programm that maschine to produce steak. Maybe one can even use the medicine synthetyser to produce something edibile. [Answer] The Russian and American space agencies both had a look at this (1960-70s I think). Short answer is: I hope they like glycerol and starch! This is the closest I know of that we have come to producing synthetic food from water and electricity (apart from 'electro single cell protein') and even then you would slowly be dying from vitamin deficiencies. FYI I would hope that crew morale is good or future technology has improved the flavour as having this all day everyday would be interesting! [Answer] One or more unmanned/automated resupply ships/cargo pods with reserve fuel that were sent ahead and are parked in handy locations along the route such that it could reach a crew before they starve to death. In the event that they are not put to use, they return to earth or something such they aren't a total loss. [Answer] Tholins! [![tholins on europa](https://i.stack.imgur.com/IFTor.jpg)](https://i.stack.imgur.com/IFTor.jpg) [Tholins](https://en.wikipedia.org/wiki/Tholin) are a wild mix of thousands of different organic chemicals. Deposits of tholin on planetary surfaces is thought to be common throughout the universe, because the elemental precursors of tholins and the energy to make them are common thru the universe. Titan is covered with thick deposits of tholin. Depicted: cracks in Europa, crammed with tholiny goodness. Bacteria can eat tholin. <https://www.wired.com/2016/09/plutos-moon-charon-got-dusty-red-cap/> > > Tholins have been a scientific pet project for decades. ‚ÄúThis tholin > material has been made in labs for about forty years, but the stuff is > so complex that we couldn‚Äôt analyze thoroughly until recently,‚Äù says > Dale Cruikshank, an astronomer and planetary scientist at NASA's Ames > Research Center. Now they know that when you hydrolyze tholins, those > complex bonds between hydrogens, carbons, nitrogens, and oxygens can > recombine to form amino acids. > > > Nobody knows exactly how life got started, but most scientists agree > that amino acids were probably involved. ‚ÄúIt‚Äôs also edible, in a way. > People have made the this stuff and exposed it to different kinds of > bacteria, and some can metabolize and even thrive on it,‚Äù Cruikshank > says. "To me, that drives this connection to pre-biology even closer.‚Äù > So, tholin soup, anyone? > > > So too your scientists! Now - tholins probably contain a lot of stuff that is not good to eat. OK, mostly not good to eat. But there are amino acids in there, and those are good to eat! Presented with enormous mounts of tholins, your castaways could 1: Use science to purify the amino acid fraction. Then chow down. Even if it is only 0.1% they have mountains of the stuff. 2: Grow yeast or bacterial on tholin slurry, rinse off unmetabolized tholins, and eat the bugs. 3: Warm up the tholin to drive off the worst stuff, eat the rest and hope for the best. 4: Give up on 1 (too hard), 2 (making grow vats did not work) and 3 (one time project). Instead, distill off volatiles, retaining only the ethanol fraction. Get drunk. Wake up; repeat. [In unexpected discovery, comet contains alcohol, sugar](https://phys.org/news/2015-10-unexpected-discovery-comet-alcohol-sugar.html) > > "We found that comet Lovejoy was releasing as much alcohol as in at > least 500 bottles of wine every second during its peak activity," said > Nicolas Biver of the Paris Observatory, France... > > > Ethanol has plenty of caloric value. Your tholin brew will have piquant notes of ethanol, ammonia, melamine and hexane. > > Korolev looked appraisingly at the clear fluid in the beaker, tilting it > back and forth. He took > a careful sniff. He lifted an eyebrow. Then he raised the beaker in a > silent toast to his crewmates and downed the whole thing in a gulp. > He ran his tongue over his teeth, regarded the empty beaker > phlegmatically and nodded. "A little ice will help." > > > " [Answer] By "no signs of life" does that mean that there is nothing edible on the planet? Like is it just a barren rock, or is there vegetation on it? Extending this idea further, are there other planets along the way back that have vegetation or maybe some kinds of animals they could eat? [Answer] If they are at the level of technology in which they have faster than light travel via warping space, it would be unsurprising to introduce some form of matter replication. They could have a basic nano-level molecular assembler expected to be used for spare parts and other inorganic structures that could be hacked to produce simple foods. In fact you could come up with some explanation involving the molecular assembler being a component of the faster than light drive. If you want them to not have an inexhaustible source of food make the hacked food replicator depend on a finite supply of raw materials they extracted from the planet for this purpose. ]
[Question] [ Magic in a certain world works as follows: * Elvish is the "language of magic", meaning all magic is chanted/invoked using Elvish * To invoke the `fire` spell, the user must: 1. Chant "fire" in Elvish either out loud or in their head 2. Understand the meaning of "fire" in Elvish (you can't use it without knowing what "fire" means) 3. The user must also consciously want to invoke the spell * Magic cannot be used without chanting either out loud or in one's head (so-called chantless) explicitly in Elvish. (any other language won't work) The elves continue to use that language as their common to the modern day. However, humans and other species, are also capable of using Elvish (like any human can speak English, German, Russian, Chinese, etc) but still use their own common languages. With the requirements to use spells, accidental casting (mainly by small children) should be a relatively small problem. The elves also use it as the common language without much problem. In this world, magic is a must. One would find it very hard to survive without using magic. Considering all that, in seems like Elvish should be the common language for everyone since: * It would be easier to learn magic if Elvish is also the common language * People in every country learn how to use magic regardless of social status * Magic is an absolute must-know * Anyone can learn Elvish (no biological differences significant enough to make one species unable to speak it) However, since people first learnt to use magic, new languages have been created by different countries and species. Everyone used Elvish at first, but after thousands of years, they've diverged from it. What reasons may people in such a world have to decide to use languages other than Elvish as their common language? [Answer] You may not need to. Languages are decidedly not fixed. In fact, it's well accepted that the borders between languages are, frankly, pretty darn arbitrary. They're placed along lines which make it convenient for linguists to talk about languages. You may be an English speaker, but you know what a sombrero is, and you probably know what amore is. Some things have a certain je ne sais quoi about them. Words get inherited rather quickly. One may not learn Elvish because its simply too difficult of a language to master. Elves typically have many more decades than us to master it. However, the magical phrases from Elvish will certainly be absorbed into the common tongue faster than baka or kawaii were abosrbed into the American anime lover's speach. It's possible only a few people will grok Elvish. And in that, I chose to bring in a verb "to grok" which was invented by Robert Heinlein for his book Stranger in a Strange Land. Yet I expect many who read this answer will know what I am talking about. [Answer] ## Linguistic inertia. Each region and culture developed their own languages, and people tend to pass on to their children the language that they are most comfortable speaking in, so the primary language in a region is going to persist unless there's a large influx of people who have a different native language. Beyond that, there are three broad categories of reasons for your described scenario: Cultural, Linguistic, and Magical. Some examples: ## Cultural Elves are horribly elitist, and refuse to let the other races converse in Elvish for everyday conversation. The Elvish Empire is big enough that none of the other races want to bother. They allow magic use because trying to ban that would be more effort than it's worth. Humans are horribly elitist, and refuse to use the language of those stupid elves. Except for magic. Just because we're better than them, doesn't mean we won't take advantage of the tools they provide. Human nobility is horribly elitist, and enforces non-elvish languages in an effort to keep the peasants from learning magic. ## Linguistic Elvish can be used for normal speech, but the grammar is weird, and it takes three times as long to say anything as it would in human languages. Those languages are more convenient. (If speaking a thing can make it true, then you're going to need a language that is very specific and exact in order to make the effects come out the way you want. There needs to be an unambiguous description of anything, and that's a pretty hard ask for most languages) Human vocal cords aren't built well for Elvish. They can speak it without mangling the pronunciation, but speaking for long periods is hard on human throats. The language of magic has no word for 'Love'. ## Magical Speaking elvish as a first language means that small kids will have access to magic. This is bad. Elves don't have this problem because elvish children don't become verbal until much later in their development - they use sign language up until that point\, and are mature enough to not abuse their power by the time they have it. It's entirely possible to speak casual in Elvish - but you can't lie in it, and humanity loves lying. Unlike Elves, humans sleepwalk, sleeptalk, and on rare occasions (but often enough to be considered a serious problem) sleep-spellcast. Humans keep parrots, and nobody wants the parrots figuring out how to cast spells. \This is a real thing, by the way - you can often teach kids sign language before they're old enough to form words. --- These are just examples. Feel free to come up with your own! [Answer] # Emotions Have you ever had one of those in the office where your boss asked you to do something ridiculous and demeaning and in your mind you formed a series of words that explained to them exactly which object you'd like to stuff up which of their orifices? And you really, really wanted it to happen? Yeah, so don't do that in Elvish. The Elves might have some semblance of control over their thoughts in difficult, but Humans keep doing terrible things to each other whenever they get angry (or horny, and in a bunch of other situations as well) because they have more trouble controlling their inner voice. So they don't want to use an inner voice with severe consequences. And once your inner voice is in a different language, your spoken language will change to match, unless you're serious about the things you say and think to magically become true. [Answer] # Grammar. Oh, sure, casting a spell in Elvish is easy. You just have to chant a noun over and over again. Maybe sometimes it's a verb instead. But it's always just one word, or a short phrase, that you've learnt how to say properly. You don't have to do anything except repeat it. But have you ever tried to actually put together a sentence in Elvish? It's a nightmare! They have inflections for everything. Nouns have five different categories ("gender" doesn't even begin to cover it). Every verb is irregular. Anyone who can cast a fire spell knows the word general-concept-of-fire. But they don't have the first clue how to say this-fire-here or fire-that-was-just-lit or fire-that's-been-burning-for-a-while. Never mind a grammatical sentence like this is fire or look at that fire or my house is on fire. --- ## Further thoughts How did this situation come about? The answers will depend on your world, but exploring them could be interesting. Did the elves discover the magic words? As in [WillRoss1's answer](https://worldbuilding.stackexchange.com/a/164151/239), maybe the ancient elves found that certain words made certain effects; or else they learnt the magic words from the gods, or whatever. In any case, once they had these words, they built their language around them. Others who want to use magic don't need to retain the whole Elvish grammar—they only need its vocabulary, and only the bits that pertain to what they want to do. (In fact, if this is the case, you wouldn't even need to have the complicated-grammar excuse—or any excuse—for people not learning Elvish. If the vocabulary is all that they need for magic, then that's all most people will bother to learn, no matter how simple or complicated their grammar is.) Or, is it the language of magic because it's the language of the elves? Are they "closer" to magic somehow, or its source, or whatever? In that case, maybe knowing the Elvish language in full actually does unlock new magical possibilities. Chanting "fire" over and over is enough to make something catch fire, but if you can chant a whole song about fire, in good, grammatical Elvish, you can do things unheard of by most people. This is probably a well-kept secret! Most people really do think that just knowing the Elvish word and chanting it is all that there is to magic. Those who know better (mostly elves) almost certainly use it as chantless magic, as you called it, doing all the chanting in their heads. [Answer] It is dangerous. There is a significant diglossia (much like Arabic today or Latin in the later Roman Empire, or perhaps not bigger than in the contemporary Czech) – the common, day to day language is significantly different from the high level (perhaps written only) register. Since magic is invoked by words in the “high” language, and the common language has significantly different pronunciation, it is safe to use. But when speaking the magical variant, you can never be sure when an unintended, random spell fires – you say “Can I have a glass of water, please?” and get drenched by sudden magical shower. Or even worse, the language has a lot of homonyms and one syllable words (see modern Mandarin or English), and you never know when a random syllable combination invokes a spell (especially if you do not get the stress or accent or tones right, because it is not your mother tongue). [Answer] Change is hard Other languages likely originated before or around the same time as elvish. When it was discovered that the elvish language had special properties, other cultures were already entrenched in their traditions and saying "Ok, everybody use this other language now" isn't so easy. The United States still uses Fahrenheit instead of Celsius simply because it's what we're used to, even though the latter is way more intuitive. So people would still speak the language of their parents simply because it comes naturally. Magical words/phrases are limited Surely the elves cannot just speak whatever words they want and have it cast a spell, even if they really want it to. "I am now immortal", "Mountain, move", "Destroy that entire city". So somewhere along the line there are certain elvish words that can cast a spell, like "fire". Elves might have a slight advantage, but they still have to remember exactly which words do what, just like everybody else. A non elf would be far better off memorizing each of these words than learning the full language, with its grammar, writing system, pronunciations, transformations, non magical vocabulary, etc. Magic came first, not language There is nothing inherently special about their language. A certain word does not cast a spell simply because it is Elvish. Instead, the ancient elves discovered that a certain combination of sounds produced fire (sounds like a pretty Elven way to discover fire :D). Naturally, this became their word for fire. Over time they slowly discovered new sounds that were incorporated into their language with a meaning derived from their effect (explaining why you must understand the meaning of the word to cast it). However, with the exception of the earliest, most basic words (fire, water, food...), a non magical word with the same meaning (or close enough) was already in common usage, making the magical synonym unnecessary in every day speech (though some of the more commonly used spells eventually replaced their non magical counterpart). Because of this, putting in extensive amounts of time to learn how to speak Elvish would only provide you with the most basic magical abilities, that you probably could have learned in an afternoon. [Answer] Intention. If you speak the magic tongue without the intention to use its magical properties you are teaching yourself to specifically not cast spells. This can mean that people have more trouble using spells correctly when they do want to use the spells. So if you instead have a completely different language as your common and only speak "fire" when you mean to use the magic your intention is far more pronounced. Elves might be capable enough not to suffer from this distinction between intention and spoken words but other races would. Additionally languages continously evolve and especially for children. Most answers thus far have used this as a justification for other languages to develop, but what about the backlash on magical power from this evolution? Someone who grew up with Elvish as his common would also have learned Elvish slang words that will eventually help evolve the language. But if he tries to cast a spell and he uses this slang instead of the proper elvish words the spell will fail or even backfire. So some species tried to avoid this pitfall by creating an entirely new language to make sure that no Elvish slang enters their children's magical vocabulary and their magical potential isnt hindered. [Answer] Possibly Elvish is indeed hard. Now that creates another question: If Elvish is indeed hard, why did all races speak Elvish initially? Well, maybe Elves invented speech, and were able to teach it to individuals of the other races, but those individuals couldn't pass the teaching on. Which was a non-problem as long as all races lived together (each parenting group would have at least one elf in it), but over time, groups wandered off and lost their connection to the elves. Everybody expected them to lose language, but instead it turned out the languages would degenerate into something non-magical. On a tangent, maybe elves believed that magic and speech are one and the same, before the other races demonstrated to them that there is such a thing as a non-magical language. Maybe actually all of Elvish is magical. The easiest magic is to convey a thought to another mind. There isn't much of a difference between talking to a person to make something happen, and talking to a stone to make it float, transmute to gold, or whatever you want it to do. Possibly magic got restricted. Magic turned out to be dangerous if the common plebs has it. Heck, even if nobility has it it's dangerous. You can kill with it, you can mind control with it, no state is going to allow this to happen. Each kingdom has some institution that controls unlicensed use of magic (or Elvish). Only trustworthy/mind-controlled/properly educated individuals are allowed to learn Elvish anymore, hedge mages/witches/heretics/unlicences mages are brought down and neutralized according to whatever is the usual course of action. The details will vary between cultures. Similar cultures will have similar institutions and rules. Kingdomes may even share institutions, whether it's a Church or a School of Magic: It may have gained power of its own, because it is (a) absolutely essential and (b) shouldn't be under the control of just one kingdom. Possibly magic got banned. Too dangerous in non-Elvish hands, if no elves are around - it must have been a non-problem in the old days, so I guess elves could prevent the danger, by education or maybe they have a way to neutralize magic or the danger. There are many possible dangers here: * Accidents. * Addiction. Non-elves tend to lose control over time and become a danger to themselves and the public. * Atrocities. Magic was used for genocide (we even lost a sapient race that way, that's why we have lost cities in the jungle), or for large-scale mind control. * Side effects. Magic use by non-elves attracts demons (malevolent entities). Elves can deal with these, non-elves cannot (because they talk yet another language that only Elves can learn, or some other reason). Disadvantages to non-elves. * You can't lie in Elvish. * Or maybe you can lie so well in Elvish that your lie becomes the truth. Non-elves want some stability in their environment, the land of the elves is pure chaos. * Magic turns out to be addictive. Elves can cure that condition and routinely do, but if no elves are around, mages become a danger to themselves. (If they also become a danger to the general public, we have a reason to control magic/Elvish.) [Answer] TL/DR: As usual, we can link magic with such ability as mana. Nothing comes for free, so to perform a magic act you have to spend some mana, which is a finite resource with slow-speed replenishment (hello, free-to-play games! you're so true!). This is why Elvish-all-the-time speaking may be devastating for non-Elvish races. Because unlike First-borns, they do not feel True Harmony Thrills and have to earn mana hard way, spending hours or even days to recover after each and every chanting. [Answer] Where divergance of languages occurs, The most observed cause throughout history is physical isolation. Historically, tribal continents IE: Africa and Australia typically had different languages for almost every tribe - The degree of divergence depended on geographical seperation. Tribes that had occasional contact often shared or at least knew some of their neghbouring tribes language, but the less frequently any group of peoples had contact with another, the less shared language there would be between the groups. In your world, there could be numerous reasons in which races have limited interactions beyond merely the Geographical. Political: * Communist / Capitalist * Tensions between nations over resources Cultural: * Different ways of life / cultural values that result in races seeing themselves as being incompatable (Think East vs Western World) * Taboos (Inter-race marriages etc) Religious: * Religios factions that believe they are the creators chosen people, Elitism surrounding such views [Answer] * To talk in secret/code for various reasons such as plotting anything illegal, anything against a neighbouring group/tribe/country. * To identify people of your alignment, when a society is so large that you don't know everyone by face it is helpful if they speak 'your' tongue and not someone elses to help identify who they are - You can see this happen to this day in cities where people will use phrases that make no sense in the context being spoken but does make sense to those who know the true meaning (this isn't another language but an adaptation of the meaning of a current one to divulge information) ]
[Question] [ I'm designing an alien tree species that produces small purple fruits at the edge of its branches. Now, a few seconds after one of these fruits falls from the tree, it makes a small explosion, so that its seeds can grow into new trees in a different location. My question is, how could such a mechanism of explosion work for a fruit, and how could something like that evolve in the first place? [Answer] You're lucky, this is a case of "nature already did it". A combination of melting resin, high internal pressure and physical tension works for various existing plants such as the squirting cucumber, touch-me-nots, persian silk trees, yellow woodsorrel and violets. You can watch slow-mo videos of them on youtube, decide on which method you prefer and then just copy it. [Answer] You have two really good, informative examples (one as an answer, one in the comments) of real-world scenarios. So here is a really wild, out-there but plausible answer. The fruit has formed a really good symbiotic relationship with a particular strain of bacteria. The plant provides these bacteria (located in the fruit pod) with nutrients, and the bacteria produces methane gas as a byproduct. The fruit pod outer membrane is made of a tough, elastic protein (similar to intestines) that constrains this methane under pressure. When the seed pod (fruit) falls, the nutrients to the bacteria are cut off, and this signals the bacteria to start consuming the enveloping membrane of the pod. This forms a hole, and the external membrane collapses like a balloon. The guts of the pod are expelled. Even better The exposure of the bacteria to air causes them to create high voltage sparks, that ignite the methane, creating an even larger explosion, that propels the seeds far and wide, along with the bacteria. Thus, the seeds and the symbiotic bacteria are equally dispersed. Very recently, it has been discovered that, indeed, certain human gut bacteria do produce electricity in sufficient quantities to be usable for this purpose. [The Bacteria in Your Gut Produce Electricity](https://www.livescience.com/63569-gut-bacteria-produces-electricity.html) The electricity could be stored in biological capacitors until it becomes sufficient enough to cause ignition. [Biological capacitance studies of anodes in microbial fuel cells using electrochemical impedance spectroscopy.](https://www.ncbi.nlm.nih.gov/pubmed/25656699) The physics textbook, along with the Chemistry and Biology textbooks, are recently getting very thick indeed. Knowing this makes sci-fi writing all that much easier, without calling on magic. [Answer] The best Earthly example is the 'dynamite tree' ([Hura Crepitans](https://en.wikipedia.org/wiki/Hura_crepitans)). The mechanism depends on 'dehiscence' which is seam[s] in the seed pod that remain weak while the rest hardens. If the hardening takes place unevenly then stresses can build, like a leaf spring. When the dehiscence zone begins to decay, it will let the springs go, and [the seeds can be propelled](https://www.youtube.com/watch?v=lNlk2V9yFhM). It probably evolved in stages: A decaying pod to release the seeds; a hardening pod to protect the seeds; spring power selected as farther dispersal out-competes. [Answer] A member of the cucurbit family (same as cucumbers) does accumulate enough pressure to detach and blow-up at the slightest touch. Its liquid content is spitted along with the seeds. The plants belong to the genus ecballium. <https://en.m.wikipedia.org/wiki/Ecballium> If you want to add a chemical explosion, the fruit may contain two sacks of chemicals at its center. The seeds will develop at the periphery. When the separating membrane ruptures, the two chemicals come in contact and react violently. The fruit explodes and scatters the seeds. [Answer] Water pressure and weak skin: the plant "pumps" water into the fruit as it ripens, while thinning the skin. When the ripe berries (a type of fruit which just happens to be small) falls to the hard ground, the skin bursts, and the seeds -- which are on the outside of the fruit, by definition of being a berry -- get pushed away. ]
[Question] [ So I have various factions with submarines and surface ships battling it out for control over various underwater resources. One of the rarer and more lethal weapons is a "stealth torpedo". It presents a serious threat when employed because as its name implies, it is very difficult to detect and, by the time it is, it is often too late for evasive maneuvers. Would It be possible to somehow muffle the sound of the engine for defeating passive sonar as well as bend sound waves around the torpedo hull like a stealth fighter to beat active sonar? Currently, I have a system similar to the Caterpillar Drive from Red October driving the torpedo. However, as far as I can tell from the research I have done, the few prototypes in existence are too slow, impractical, and not to mention too big to fit in a torpedo. [Answer] The state of the art for subs is stealth. You can't hit what you can't see. When sneaking around everyone uses passive sonar since active sonar lights everyone up equally. The idea is that you need to minimize cavitation, that's what happens when the spinning prop blade (which has a shorter radius near the center) creates a density differential in the water and forms a bubble. The resulting bubble collapses making noise. Minimize that and you're good. It works better at slow speed, but you can kind of tune your prop for the speed you want. The process is well known, but solving the problem requires lots of number crunching and some good understanding of fluid flows. Then one day one of the major powers had this break though in out-of-the-box thinking. Stealth is only part of the battle. When things get heated, everybody lights up active sonar, bathes the battlefield in light so to speak. At this point you want to fire the fastest weapons you can. So instead of making a slow quiet torpedo, they made the fastest they could. They put the prop on the front, they maximized cavitation and put a rocket on the back end of it. The little guy swims in a pocket of air and travels like a bat out of hell. Meanwhile the other side worked hard on quiet torpedoes. In a situation with multiple sources of active sonar and rocket powered torpedoes/torpedo killers, I'm not sure a stealth torpedo is actually going to win any battles. --- [Answer] Fishpedo You want stealth. Then be stealthy. Blend in. The ocean is full of fish. Look like a fish. Move like a fish. Have the sonar profile of... you get it. The sub cannot destroy every medium sized fish that comes into the vicinity. Have it swim around lazily in a fishlike matter. Then it gets close and BLAM! The Mossad shark depicted here has a propellor - no, no, no. The slow fishpedo should propel itself by swishing its tail back and forth. The squidpedo would jet along like a squid. The hagfishpedo would do what hagfish do. [![enter image description here](https://i.stack.imgur.com/mlz31.jpg)](https://i.stack.imgur.com/mlz31.jpg) <http://www.keiththomsonbooks.com/blog/mossad-sharks> [Answer] Even if you could eliminate the sound of the engine and keep the torpedo from reflecting sound back to an active sonar system, it wouldn't make the torpedo undetectable. There's a technique known as [acoustic daylight imaging](https://scripps.ucsd.edu/labs/buckingham/wp-content/uploads/sites/60/2015/04/ADHandbook1999.pdf) that uses changes to the ambient noise of the ocean to produce an image. To such a system, your "stealth torpedo" would present a clear shadow moving against the background. [Answer] The problem with a stealth torpedo is that it is moving and displacing the water around it. If it is moving very fast (like a supercavitating torpedo) then the amount of water being displaced will be very large. We can see some analogues in aircraft, for example sonic booms for supersonic aircraft, but much of the noise an aircraft in flight makes comes from the propulsion system moving masses of air backwards to provide the forward thrust for flight. But that's not all. Even a glider is actually rather noisy when you are inside. Now water is 800x denser than air, so the amount of movement and displacement is amplified by a huge amount due to the higher fluid density. This is not to say "stealth" underwater is impossible. A submarine covered in metamaterials optimized to the wavelength of standard or known enemy sonars will evade active detection, and so long as the captain maintains silent running discipline and moves relatively slowly, the submarine itself will be very difficult to detect. But this is actually quite the opposite of a torpedo making an attack run against a ship or submarine. The best sort of "stealth" torpedo is actually targeted using passive means like hydrophones or MAD, and either air dropped by helicopter or airplane, or launched at the enemy sub by a rocket and drops into the water quite close to the target. There the enemy has very little time to react to the sudden appearance of an active "fish" making a run, since they did not realize they had been spotted and never "saw" the torpedo coming until it hits the water. [Answer] The stealth torpedo exists today. It called a sea mine. They don't make noise. They can selectively attack vessels. And, covered with sound absorbing material, active sonar has a difficult time spotting them. The design of submarines is to get close enough, without being detected, to fire a weapon. Once the weapon is fired, everyone knows where you are. The design of torpedos is to have such a great range and velocity that the target has to focus on evading the torpedo giving the submarine, or subma to aficionados, slink away and hides again. Ship killers fired by submarines sound like locomotives bearing down on you -- at least that is what the sonarman told me. The only way to make them quiet is for them to move very slowly. But, the torpedo ejection mechanism is very loud, so a slow-moving torpedo after a big loud sound of the launch is what subma's call very very bad. In many ways, submarines are like artillery. You shoot, then you scoot, if you want to stay alive to shoot again. [Answer] The japanese used oxygen propelled torpedoes, which were hard to detect from the air, since the oxygen bubbles were absorbed by the water, in contrast to other gasses. You could maybe try to extend this system and use it to reduce the moving parts and use a jet system as propulsion. What you also have to consider is the following. A traditional torpedo works via a displaced water and shockwave, not via the impact. That is why they are actually quite big. So your goal should be to reduce their frontal profile as well, to reduce the water displacement and the possibility of active sonar detection. If your target is something like a carrier or a strategic sub, you could make the torpedo "smart" replace the payload with something like a long shapedcharge, that attaches to the hull, and rips it open, via lance explosion (think of ebene emael and the nazis), or the cut (cooper plate method used in demoltion), or a real small nuclear device, (if you are in the near future) [Answer] There are two paths you can take to bruteforce your way around detection. # Supercavitation [There are some torpedoes that through sheer thrust cause the water around them to vaporize](https://en.wikipedia.org/wiki/VA-111_Shkval). They literally fly inside a bubble and reach speeds which regular torpedoes cannot match. With future tech it would be doable to make them faster than sound underwater. And you can hear them coming if they are coming faster than sound. # Early preparation Another russian invention, [the Poseidon](https://en.wikipedia.org/wiki/Status-6_Oceanic_Multipurpose_System) is a torpedo with a payload of four Tsar Bomba's. If you haven't heard of the Tsar Bomba, you haven't browsed this site enough. The idea of the Poseidon is not to be fired during a battle, but to be activated up to a a couple decades prior to the battle. It makes its way toward coastal cities slower than a sleeper shark, which makes ot very stealthy. Once an enemy power threatens you, you just send the signal, and then your enemy is a few cities shorter than it was a few minutes before. There is no better deterrent to aggression. Some conspiracionists say that there are already many Poseidons stationed worldwide after its unveiling last year by Putin. Of course no one can either confirm or deny that right now. ]
[Question] [ This question already has answers here: [Building a Megalodon proof boat](/questions/27090/building-a-megalodon-proof-boat) (2 answers) Closed 7 years ago. The [Megalodon](https://en.wikipedia.org/wiki/Megalodon) was an 59 feet (18 meter) long shark said to have roamed the entirety of Earth's ocean. Of course, it's quite extinct. However, what if somehow it managed to survive all the way to the Medieval Era? A shark over half the size of a [Galley](https://en.wikipedia.org/wiki/Galley#Surviving_examples) back then and it was one of the largest ships during its time. It also had a estimated bite force of 108,514 N (24,390 lb) to 182,201 N (40,960 lb) which is around 7 times a Crocodiles bite force. And if Crocs can ruin the motor on modern ships... Would the very existence of Megalodon cause all Sea travel to grind to a halt? Bonus: If so, how could these ships be defended? (With the technology of the Medieval ages. We can't have you dropping a depth charge treat can we) [Answer] # No Megaladon is not fundamentally a more fearsome or ferocious beast than a sperm whale, which is also carnivorous, of similar size, probably smarter, and has as documented capability to sink [240 ton](https://en.wikipedia.org/wiki/Essex_%28whaleship%29) sailing vessels. Humans have hunted sperm whales, probably since pre-history. Even to the modern day, they do it by jumping off a boat and [stabbing them with a pointy stick](https://www.youtube.com/watch?v=_tqW8YZDE9o). Thats pretty rad. Humans would HUNT, KILL, and EAT megalodons, just like they would anything else in Earth's biosphere. Questions about the ability of various mega-fauna to compete with humans are laughable. Humans are the most merciless, deadly predator to ever grace this planet. You and I might be computer-bound bums with poor vision, but our ancestors were super-intelligent, awesomely effective pack hunters. No creature alive, from a blue whale to army ants, stood a chance against a pack of cave men. [Answer] # No Whales didn't stop anything at all and they're larger than Megalodon and fairly destructive when they've been stabbed with a spear. I don't know who'd be fool enough to spear a mega-shark... Since ships are largely wooden, there wouldn't really be a reason for the mega-shark to attack a ship unless it looked like prey. For defence (if mega-sharks turned nasty), you use large nets. They'd be big enough to foul the shark's movements until it suffocated. [Answer] Unlikely. For starters, human ships in this era hugged the coastlines for the most part, while large sharks are typically deep water hunters. Second, the hull of a ship has a profile that wouldn't register as prey for the megalodon, unless it was in cloudy or bloody water. Finally, sailors back then DID think there were "sea monsters" in the ocean, yet they still went out. Plus European waters are cold, so they would be less likely to be found there. Since megs probably ate whales most of the time, the most likely time humans would encounter them would be while whaling. European whaling was mostly in the cold northern waters, so again, little chance finding a shark there. Pacific cultures may have learned of them though. Of greater concern is the adaptive pressure the continued existence of megs may have placed on other marine life. One would think that aggressive predatory whales may have become even more so, and even plankton feeding whales may have developed more defenses. So the whaling industry may have been much more dangerous. Other species of large fish and marine animals may also have become more dangerous (or been driven extinct by the meg). And of course if the meg survived, what other Miocene macro-predators also survived? There were giant crocodiles during that time as well, and those probably WOULD be a direct threat to humans. [Answer] ## Do Megalodons like to chew on ships? If the answer is no, the answer is "Don't worry about it. They are just like whales. Huge, pretty to look at but completely harmless to ships." The answer is likely to be no if the Megalodon's prey-not-prey filter does not identify a ship as prey. If the answer is yes, the answer will be a bit more complicated. Just remember, Megalodons ate pretty much [everything that moved](https://en.wikipedia.org/wiki/Megalodon#Prey_relationships). ## Yes, they do ...then we can expect a mix of passive and active measures to thin the Megalodon "herds" or negate their threat. Assuming that Megalodon attacks are fairly rare, it's still worth it for ships and crews to go fishing, trading or raiding. These forays onto the sea will be the test fleet to show what works and what does not in terms of survivability. ## Passive Measures Armor Plating - Despite the unprecedented bite force of the Megalodon, if the ship can make itself hard enough to chew then perhaps the Megalodon will look elsewhere. ## Active Measures "Sharking" Ships - Just as whaling ships go looking for whales to kill and process, so too would a sharking ship. Lookouts - Active measures such as spearing or poisoning require the crew to know when a Megalodon is in the area. ## Cultural Make it a delicacy - Humans, for some really odd reason find that anything labelled a "delicacy" is really good eating despite everyone else's opinion that it's completely disgusting. Have some enterprising chef make a dish featuring Megalodon steak. As these things often go, demand for Megalodon flesh will increase thus making it profitable to hunt it. If it's very risky to hunt giant sharks, then the price will be very high (thus ensuring a constant stream of fisherman wanting to make their fortunes). ## Conclusion Yes, Megalodons are the top predator of the sea but they're no match for tool-using monkeys. ]
[Question] [ The enemy boss just threw a spear at you, you tried animation cancelling to iframe and dodge the projectile spear but your finger slipped off the controller and now you've got a spear piercing your skull through the mouth and stuck on a wall, you are basically hanging off the spear like a sack of dead meat. Your party members are dividing tasks to handle the situation, some of them are hooking the enemy boss with leashes and chains while others are shooting arrows and bolts at his knees, the party tank has climbed over the boss head and is stabbing his eyes repeatedly. But this will only slow down the boss as he can regenerate really fast, and your party needs you in order to survive and kill the boss. Meanwhile the party healer is resurrecting you, but they can't recreate neural pathways, they can only force your body to regenerate at incredible speeds. The dead parts of your brain will be replaced with new neurons, and the blood loss will stop. Now that you gained back conscience you feel a lot lighter, overheating whilst also suffering immense thirst and hunger. The healing spell consumed a lot calories. But you can't stop, the lives of your comrades depend on you, you have to fight as soon as you cross the line between death and the living. So wake up party leader! We've got a giant troll to kill. Question below What is the likelihood of you remembering how to fight after your brain was pierced by a skull shattering projectile spear if it was regenerated? For real, I need to know the mathematical odds, this is part of the game. If such data is impossible to guess/gather, please suggest some specific works about brain injury that could enlighten me. [Answer] Through the mouth will miss the cerebral cortex. I have from the OP: the spear entered through the mouth and the end result is that you are hanging from the spear. [![angles](https://i.stack.imgur.com/kkeCi.jpg)](https://i.stack.imgur.com/kkeCi.jpg) I have added blue lines to represent possible spears. The steepest line (and one which would, I think, result in you sliding off of the end of of the spear instead of hanging) disrupts the brainstem and cerebellum, neither of which contain higher functions and learned behaviors. Realistic trajectories for a spear from which you could hang have the spear missing the brain entirely and disrupting the cervical spinal cord - or not even that. Assuming you are healed, the functions of the spinal cord and brainstem are hardwired. You do train your cerebellum to some degree using muscles and balance as an infant and toddler. If you want to have some sort of aftereffect of cerebellar damage, it could be the functional motor equivalent of being very drunk - staggering, missing, slurring words. Higher functions that you learned - words, concepts, how to load up your magical megaweapon, how your kungfu kata goes move by move (the moves themselves might be in the cerebellum) are up in the cerebral cortex which was spared. You would remember what to do. Whether you could do it depends on the cerebellum. It might take you a couple of tries. [Answer] Ever heard of [Phineas Gage](https://en.wikipedia.org/wiki/Phineas_Gage)? Had an unfortunate accident involving a metal bar and an explosive charge. > > the tamping iron‍—‌1+1⁄4 inches (3.2 cm) in diameter, three feet seven inches (1.1 m) long, and weighing 13+1⁄4 pounds (6.0 kg)‍—‌entered the left side of Gage's face in an upward direction, just forward of the angle of the lower jaw. Continuing upward outside the upper jaw and possibly fracturing the cheekbone, it passed behind the left eye, through the left side of the brain, then completely out the top of the skull through the frontal bone. > > > Illustration of the damage: [![An illustration of the bar piercing Phineas Gage's skull](https://i.stack.imgur.com/4l1HW.jpg)](https://i.stack.imgur.com/4l1HW.jpg) From an account by the physician who was first on the scene: > > Mr. G. got up and vomited; the effort of vomiting pressed out about half a teacupful of the brain [through the exit hole at the top of the skull], which fell upon the floor. > > > Astonishingly, Gage survived... it took him a few months to recover physically (at least in part due to infections received from the wound) though his personality was significantly and permanently altered. There is precedent, therefore, for humans to survive quite unpleasant brain trauma. Good news for your player! --- > > What are the likehoods of you rembering how to fight after your brain was pierced by a skull shattering projectile spear if it was regenerated? > > > You would need to model which bits of the brain were damaged. There's plenty of scope for simplification and abstraction here. Mr. Gage was "fortunate" in that the bits of his brain that were damaged didn't drive anything absolutely critical. He could still walk, speak, hear, see, remember. Piercing the brain side-to-side or front-to-back has a worse prognosis. Bits of brain don't always have a clearly defined role... this stuff is diffused across the brain to some extent, though some things are certainly localized. You can research this sort of thing yourself, in as much detail as you felt you needed. I'm not going to elaborate on this stuff here, but you could conceivably model this as a kind of amnesia where both physical skills and memories may be lost. Maybe you act and feel fine, but forgot how to operate a sword. Maybe you're as deadly as you ever were, but no longer know who your friends are. You might recognise the threat of the Big Bad, but might not know how to finish them. Exactly how this is modelled (as a complex 3d voxel-based model of the brain with a trajectory calculator and a dice roll per voxel damaged, to a simple coin toss) depends very much on the style of rules you're working with (slow, complex, simulationist? fast and simple?), and the flavour of combat you want to impart (terrifying and deadly? cartoony?) and as such is a bit out of the scope of this question. [Answer] Either impossible or as accurate as the healing spell is. It is impossible since your reactions and capabilities are a combination of specific neural pathways, how much myelin the pathways have received and the trillion feedbackloops that never stop in your body as part of the remembering and steering processes in your brain. Unless the spell repairs your neural pathways exactly down to the last neuron with its processes intact and the way they were you will not just forget things, you will have a different personality and capability. Side-note: if you had your memories transferred to someone else's body then you would inherit their personality as their brain composition defines that rather than your memories. That leaves the other option: the accuracy of the spell. Spells usually are impossibly accurate. They can discern between friend and foe and they can identify what constitutes a wound that needs healing, how it needs to be healed and what is undamaged tissue. Since the spell is able to regenerate the face muscle tissue and its relevant neurons and connect those neurons to the nerves they were severed from the accuracy is likely incredibly high, and the brain tissue would have no problem healing completely, memories, skills and all. ]
[Question] [ I am building a sci-fi universe where humans have colonized the moons of Jupiter. They are very small and thus have low gravity. In fact, some of them have gravity equal to less than 5% of Earth. What would be a believable sci-fi way to artificially increase the surface gravity to make the moons more hospitable? [Answer] The answer, unfortunately, is "artificial gravity," and don't explain it. Speaking from a purely scientific perspective there is no known substitute for mass. The only known way to cause gravity is to have mass (or an ungodly amount of energy which is equivalent to said mass). We simply don't know of anything else. In science fiction landscapes, artificial gravity is simply too useful to not have. We use it all over. Nearly every major science fiction show set on a spaceship has it. Only a handful dare to deal with microgravity in its true form. There's plenty of handwavy reasons for it, but most shows seem to merely assume that artificial gravity works, and move on with the plot. Some will rely on centrifugal force to create the artificial gravity, but that only applies on stations where your people operate on the inside. Since you're on the outside of a planet, that won't work. That being said, if you were operating a mining expedition, you might be able to [spin the planet](https://www.youtube.com/watch?v=Jc-iGvpC18Y) and have "gravity" face the other way (for a short while, before the rocks of the planet break up and fly off). If you want to add some pseudoscience, feel free to say something about [gravitons](https://en.wikipedia.org/wiki/Graviton). That's the hypothetical particle in QM that is supposed to be responsible for gravity. However, nobody has been able to figure out how to work the math for gravitons, so we don't even know how to look for them, much less create them. Still, as far as believability goes, it's at least the name scientists use when exploring gravity. And besides, [microgravity is pretty cool when you really get down to it](https://www.youtube.com/watch?v=LWGJA9i18Co). [Answer] Two Options **Actual Increased Gravity** [Gravity](https://en.wikipedia.org/wiki/Gravity) is a product of mass and in the case of a human and a moon, to make the gravitational attraction increase one may either increase the mass of the human or the mass of moon. 1. Increasing the mass of the moon would create a situation most similar to "Earth conditions." One could do this by dumping mass on the outside, or by removing parts of the innards and replacing with more dense material. Either of these options are well outside the capabilities of our current civilization, and even for a civilization that was ready to colonize the Jovian system this would almost certainly be prohibitively expensive or impossible. A bigger problem would be that increasing the mass of Jovian moons would change the orbits of said moons. The largest Jovian moons orbit in stable [resonance](https://en.wikipedia.org/wiki/Galilean_moons#Orbit_animation) and adding mass to some/all of them would destroy this stable condition, leading to more erratic orbits and possible collisions between moons or with Jupiter. 2. Increasing the mass of the astronaut/settler is less commonly suggested. For instance, if a settler on some moon experiences 1/3g, and that person wears garments that effectively distribute double their weight across their body, they will feel 1g in their normal movement such as walking or moving their arms. (EDIT: As a few commenters have pointed out, this is not really a true statement. One might feel roughly 1g when performing vertical motions like raising arms or jumping, but the increased inertia from the added mass will make most movements like walking feel awkward and difficult.) This will not help with things like changing in the shape of the eyes or deterioration of the heart, but it would help a lot with muscle atrophy. This would also not help with other aspects of low-g environments such as drinking fluids, moving objects, etc. For more detail see [this](https://space.stackexchange.com/questions/132/would-wearing-heavy-clothing-be-enough-to-solve-the-health-effects-of-reduced-gr). **Artificial Gravity By [artificial gravity](https://en.wikipedia.org/wiki/Artificial_gravity) I mean simulation of gravity via an "apparent" force. This is most commonly done in science fiction by having people live in rotating habitats shaped as a cylinder or wheel. The (centrifugal) force is outward against the outer edge, which essentially become a floor that curves around. You can visualize and learn more about these schemes [here](https://en.wikipedia.org/wiki/Rotating_wheel_space_station) and [here](https://en.wikipedia.org/wiki/O%27Neill_cylinder). This could be done either on the surface or in orbit: 1. On the surface, the only way to keep the artificial gravity constant would be to rotate with a rotational axis perpendicular to the surface. Otherwise when rotating away from the surface one would feel lighter, then heavier as they approached the surface again (ferris wheel configuration). So if rotating with an axis perpendicular to the surface (merry go round configuration), combined with the moon's gravity, this would make the "floors" of your rotating habitat feel tilted. This is because force would be generated outward (parallel to the surface) but the gravity field would act downward (toward the surface). Therefore you'd need to compensate for this tilt created by the two different force components (actual gravity from the moon and the apparent centrifugal force) by tilting the floors of your rotating cylinder habitat. See the diagram below (massively out of scale): [![habitat](https://i.stack.imgur.com/CPBF1.png)](https://i.stack.imgur.com/CPBF1.png) 2. In orbit, a space habitat would be in freefall, thus experiencing what we call zero-g (like on the ISS). In this case, a rotating habitat could provide a constant 1g by spinning at the right speed for its size. If reaching the surface for mining/farming/building is necessary, it can be done by shuttling or using some future tech such as a space elevator. 3. There is a third option that I think is even less likely but possible. Habitats could be built in the interior, with the floor being the outer surface (think like being upside down in a cave). The moon could then be accelerated rotationally, until the spin simulates an outward force of 1g plus whatever the moon's gravity is. This would allow for living in subsurface dwellings at 1g, but there are big issues: First, the energy required to increase the moon's spin this much would be massive, and it's unclear how exactly this would be done besides literally strapping rockets to the moon. Second, the outward force would be most apparent at the equator, and go to zero at the poles. So in a strip at the equator this is workable, but as one moves away in latitude the effect decreases noticeably. Third, anyone on the outer surface would feel an outward force of 1g (think like if gravity on Earth reversed and you had to hang on to keep from flying off). This relates to the former issue in that it would be most drastic at the equator and not apparent at the poles. Fourth, it's up for debate whether a moon would even stay in one piece rotating fast enough to provide 1g outward. The whole thing might fly off in a bunch of chunks. This idea is commonly proposed for colonizing small asteroids, but would not be a great idea for, say, Io. Though maybe for some of the much smaller outer moons this would be more valid. What's Likely? It seems that you really want settlers to live in 1g on the surface of these Jovian moons. It is really unlikely that this setting would ever happen without handwaving some material that "magically" increases density/gravity. In all likelihood your settlers would settle (hah) for living in reduced gravity on the surface and deal with the health effects, or live in 1g in a space habitat and transfer to the surface when necessary. [Answer] # Make the moons smaller. Gravity is proportional to mass and inversely proportional to the square of distance. Two moons of the same mass but of different densities would have different surface gravities because their radii were different. If one moon were made of ice and one of iron the density of the second moon would be about eight times the first; the radius about half and the surface gravity about four times as great. So how to make the moons smaller? Two sci-fi ways that spring to mind are: 1. Crush the moon. Enclose it in an ultra strong shell (perhaps a force field?) and compress the contents. This makes your moon smaller, but would require a lot of energy to do. 2. Make the atoms smaller*. Atoms are mostly empty space, their size determined by the size of their electron shells which in turn are determined by the mass of their electrons. If you were to replace the electron with a different particle with the same charge but a higher mass it would make the atoms and thus the moon smaller. In terms of known physics [muons](https://en.wikipedia.org/wiki/Muon) have the same mass as an electron and about 207 times the mass: an atom formed by replacing electrons with muons will be 207 times smaller. Unfortunately it would also not last long as muons decay in a matter of microseconds, but if you could find some way to stabilize them or find some other particle with the right properties then you just need to set up a muon factory on the surface of the moon and pour them in until enough mass is compressed to give the desired results. Both these methods have the disadvantage that compression releases a lot of heat so your squashed moon would have to deal with that somehow. Also you loose a lot of surface area - if you halve the radius to increase the surface gravity by a factor of four then you will also reduce the surface area by a factor of four. [Answer] As others have already said, the only 2 ways are to decrease the radius or increase the mass of the moon. Both of them come with problems. Increasing the mass of the moon in an extent that brings the gravity closer to earthlike, means that you would also change it's orbit and or orbital velocity. Decreasing the radius means less surface to live on. So why change the moon when you can change the people living there way more easy? Have people be genetically engineered to keep their muscle and bone structure the same way they would be on earth and you have some nice advantages. Those people could easily lift heavy stuff, they could propell flying machines with only their muscles and so on. All it takes is some treatment that makes sure bones and muscles stay healthy + a bit of engineering newborns to keep genetical drift at bay. [Answer] Have you considered (electro-)magnetic forces? My first thought was that if the colonists had something magnetic on them, they could be pulled toward the surface by electromagnets, for which I have three working ideas: A non-toxic compound that can be magnetically attracted is spread through their body, much like some elements that are used forensically to identify where someone grew up and get in our system through the food chain but aren't there for any specific purpose. This might even already exist, though we probably don't like putting weird stuff inside us and wasting a lot of energy to create artificial forces for such purposes. This has the great advantage that by spreading evenly through the body we'd perceive gravity perfectly fine (as it would also be in the instruments near our ears that tell us which way is up, a set of three canals per ear filled with a liquid if I'm not mistaken) * Metallic implants, spread across the body, this would probably not give us the complete feeling of gravity unless we also tampered with the canals in the ears. Should be doable, though maybe not very comfortable * Suits with metal woven into them. This would give us a much more even distribution of the forces than implants at regular intervals, and we could again modify the ear canals. These also have the advantage of being adjustable to different conditions, either by just swapping them for another suite in a different environment, or by even being powered and creating small electromagnetic fields themselves. This would also allow them to respond to the following issue: Other than losing power to the electric field, which would essentially bring you back to microgravity, a far more powerful electric field would equate to bone-crushing gravity, and that would, in fact, be a very interesting hack I'd like to see in a story some day. An other point is that if you make the implants smaller and compensate by increasing the number, if you keep going you'll end up with the first solution. Then I remembered a passage from a book I started reading (or rather, hearing, as an audiobook) a while ago, here's what I remember, maybe someone else can correct anything I got wrong. I think I came across this one in Michio Kaku's Physics of the Impossible, where he theorizes on ways to implement some sci-fi ideas in the (not particularly) near future, based on what we know. The author was saying that sufficiently large electrical fields would manage to magnetize (not sure it's the right term) a lot more than the usual metals, and this would allow artificial gravity. More specifically I believe he was referring to levitation, actually lifting us off the ground. This would require enormous amounts of energy, and would possibly affect us in other ways, but maybe fusion reactors would permit it. On a side note, I should note that you can get electronics to work under extreme magnetic forces, and it would be conceivable that they are all manufactured so (fluctuations would be more of a problem but they'd be a problem for humans too with my solutions so presumably there won't be any). So this should not stand in the way of the rest of your tech. [Answer] The surface gravity of a spherical body is governed by the following equation: $$ g \propto \frac {m}{r^2} $$ Thus, there are two ways to increase the gravity. 1. Add more mass $m$. 2. Decrease the radius $r$. # Adding more mass If a moon has 5% of the surface gravity of the Earth then you'll have to add many more moons of material in order to increase the gravity to Earth levels. At this point you're no longer modifying the existant moon. You're building a new bigger moon. # Decreasing the radius You're better off decreasing the radius. If you decrease a moon's radius while keeping the mass constant then the surface gravity increases. You can do this by transmuting the moon's light elements into denser elements. Human beings can already transmute some elements on a small scale. If generalized to the right elements and scaled up, then this process could increase the surface gravity of a planet or moon. [Answer] ## Option 1: Depleted uranium shell on the moon's surface, of sufficient thickness to add the mass required, but that would add cost to whatever activity needs to break the surface. Plus the increase radiation hazard, but you're on a moon with no atmosphere or magnetic field. Alternately, a better, but more expensive, solution would be to drive shafts down to the core of the moon and dump the depleted uranium there. ## Option 2: Rather than increasing gravity across the entire surface of the moon, do it only in enclosed, inhabited biospheres. Use high pressure pumps to circulate air by drawing in in from the bottom and releasing it at the top of the biosphere dome. The atmospheric pressure plus the downward velocity of the air should act as a suitable simulation of gravity. [Answer] If the gravity on the surface of the moon is only 5% of Earth's gravity, it's an airless moon so outside you need (probably heavy) pressurized suites. This will help with the perceived weight (but not with improving movement rates, which are mostly due to ground friction. On the other side, inside you could have undergound shelters/bases with metal floors and magnetic harnesses worn on the body (this has a lot of drawbacks though). [Answer] Criss-cross your planetoid with gigantic underground particle accelerators, whose purpose is to generate collisions in the 126.0 ± 0.6 GeV/c² range, and thus artificially generate short-lived Higgs Bosons to temporarily increase the interaction between nearby matter and the Higgs field. This means that the rock inside your planetoid will be providing a gravitational effect consistent with a higher level of mass than actually exists in situ. If you can shrink and arrange these artificial Higgs generators into some sort of [Halbach array](https://en.wikipedia.org/wiki/Halbach_array), then you have artificial gravity deck-plating for your ships too. [Answer] How about the idea that humans remain as power hungry as ever. So they found a way to harness the power of a contained black hole that can be created in the core of a moon. Depending on the size of the black hole you can different power outputs thus different gravities can be created? [Answer] Since we are talking about moon colonization, I assume humanity has some advanced technology. Introduce black hole generator technology/device which can generate, contain and grow black holes under very well controlled conditions. Then install such a device at the center of the moon and at this point you have two courses of action: a) if you want to keep the moon size, feed off-moon materials to thegenerator, e.g. space junk or nearby asteroids. This, however, would required a lot of mass to be brought to the moon. b) if you dont need the surface area, strip away outer moon layers and feed them to the generator until the size is small enough to gave the desired gravity. This would required considerably less mass to be fed to the generator. [Answer] Creating artificial gravity on the surface of a planet or moon is possible without resorting to pseudo-magic. Ever been in a Gravitron? It's a carnival ride where, as the donut-shaped capsule spins, you're plastered to the wall by a centrifugal force of three Gs or so. As Ben pointed out, this force combined with the natural gravity of the moon makes the floor, if perpendicular to the axis of rotation, feel tilted. Luckily there's a simple solution: tilt the floor. To oversimplify, if you tilt the floor at 45 degrees, and calibrate the centrifugal force to equal the moon's natural gravity, you will have doubled that gravity and the floor will feel flat. For any given ratio of natural to centrifugal gravity, you can tilt the floor such that it's perpendicular to the apparent combined force. (Technically, it should be a slightly concave shape, because the centrifugal component diminishes relative to the natural along the down/in direction, but maybe don't worry about that.) Keep in mind that the bigger the wheel, the better/less nauseating it is. This results in a long, narrow, circular space with any desired g-force, which would probably make a better running track than full-time habitation. Make the colonists run daily laps to keep their bodies in shape, and let them hop around in low-g the rest of the time... That will keep their Earth muscles in shape, while keeping costs down and avoiding the need for imaginary technology. [Answer] In this case in order to increase the gravity of the moon it is technically by increasing the mass by doing so you have increased it's gravity another method is also by decreasing the speed of it's rotation [Answer] Rotational Gravity is your best bet. I'm working on a sci-fi universe similar to yours. I have what amounts to ring stations and O'neil cylinder buried into the ground of the either the asteroid or planetoid in question if the gravity is that low. Another solution I have is to use a crater and a wide maglev train like platform that runs the perimeter of the crater. Use the natural slope of the crater/ slope the platforms and the constant acceleration to induce another version of spin gravity. ]
[Question] [ Mana is the life energy of the soul that is bestowed by nature. Everything is born with a certain amount, with humans containing the most. When something dies, it's body naturally decays and supplies the ground with nutrients. It's mana dissipates back into the environment. However, there are times when orgone doesn't dissolve the way it's supposed to. Instead, the mana condenses into a thick and dense cloud called miasma. This pollutes the environment, corrupting it in various ways. Where it is heaviest, things cannot grow or grows sickly and weak. Creatures become rabid and hostile, and causes mutations in all living and nonliving things. Why would this be the case that nature's own energy would be poisonous to itself? [Answer] # Because it pushes the local ecosystem out of balance. Think about plant growth. In general, things that promote growth are good. We get thriving forests, plains, deserts, seascapes. We have an explosion of wildlife, clean air, fresh water, everything a planet could want (even if it gets in the way of certain humans). But one of the worst things for the environment is ... plant growth. In real life, plants get nitrogen from the air, minerals from the soil, water as needed, and it's all kept in perfect balance from microbial life, earthworms and other animals in the soil, pollinators, and more. New plant and animal material (especially manure) rots to provide fertilizer. In our all too real but artificially imbalanced world, plant growth is seen as science and only 3 primary elements: nitrogen, phosphorus, and potassium are considered important (plus a few minor ones). Application of these can cause all sorts of problems on farms (and anywhere the runoff goes, anywhere the water table touches). What many don't realize is this happens unintentionally as well, far away from farms or gardens. Excess phosphorus—mainly from laundry and cleaning products—runs off into streams and water ways, it goes down drains into lakes, rivers, and the ocean. And it makes plants grow. > > Phosphorus is one of the primary nutrients (along with potassium and > nitrogen) for plant growth. When phosphates were used extensively in > laundry detergents, the waste water carried the phosphorus to rivers, > lakes, streams and ponds. This led to massive algae blooms--a > condition known as "eutrophication." The algae depleted the water of > oxygen, which resulted in the deaths of large numbers of fish and > other organisms. ([ref](https://www.hunker.com/12000276/what-detergent-has-a-high-phosphate-level)) > > > In your world, naturally occurring orgone sometimes fails to breakdown properly and it forms miasma. You don't say why this happens. Is it just random? Is it happening more often because of overpopulation or more use of magic? Or is the failure to breakdown happening in larger percentages because of something else humans are doing? Regardless of the underlying mechanisms, miasma is like phosphorus, it spurs overgrowth and imbalance. Or perhaps you can compare it to mania. Healthy human minds are balanced but someone with bipolar has too much depression and too much "up." You might think the "up" part is desirable (you have tons of energy, get lots of work down) but it's actually pretty horrible to live through (though somewhat additive for some people). Healthy bodies, healthy minds, healthy ecosystems don't have those ups and downs. They have balance and carefully tuned systems. This means they can recover from things that life throws at them. But if you push something out of balance often enough, it will harm it. Humans can recover from injury, but some injuries are too grave, or too repetitive to come back from. They can recover from the death of loved ones, but people who survive genocide are never the same again. Ecosystems recover from fire, but not from the determined reshaping of land and water by farmers. Miasma is something living things can deal with, in small doses. But when it's a larger dose, or a more prolonged smaller dose, it's detrimental. [Answer] # Too much of a good thing can be bad for you There are many real-life examples of things1 which are "life giving" or crucial for life - in the right amount - but exposure to higher concentrations or for too long a duration can be detrimental to life or downright lethal. Additionally, sometimes too much of something isn't dangerous on its own, but it prevents or reduces access to some other vital thing. Some quick examples include: * Oxygen, (as O2) mixed with nitrogen, CO2 etc. at the ratio of ~21% is essential to all land creatures, and it is possible to breath even 100% oxygen for limited time without any detrimental side effect. However: + Exposure to concentrations higher than 21% can lead to [oxygen poisoning](https://en.wikipedia.org/wiki/Oxygen_toxicity), which "[...] can result in cell damage and death" as the Wikipedia article puts it. + As ozone (O3 - same element, different molecule), even concentrations of 5 parts per million (0.0005%) are defined as "Immediately Dangerous to Life and Health Limit (IDLH)"[[citation]](https://en.wikipedia.org/wiki/Ozone#Safety_regulations). * Sunlight in moderate amounts is "healthy" - it allows plants to generate oxygen, is important in vitamin D synthesis in humans etc. Too much of it will wilt plants, cause sunburns (and increased risk of skin cancer) in humans and can raise environmental temperatures high enough to cause brush fires. * Water are crucial for life. Imbibe too much and you risk [water poisoning](https://en.wikipedia.org/wiki/Water_intoxication). Additionally, land creatures drown in water since as too much of it prevents access to air. --- 1: I'm intentionally use the vague term "things" so it can cover anything from substances to energies etc. including magical / spiritual phenomena. --- # So, why is too much life energy dangerous? If this mystical "life energy" is what powers life and encourages growth (in moderate amounts and concentrations), too much of it is harmful to living things as it accelerates wild and rapid growth: * Mild effects can be things like cancer and other various tumors (cells and tissues growing too fast or uncontrollably), partially blocked "pipes"2 etc. This isn't immediately painful or even noticeable - but can lead to illness or death in the long term. * At moderate levels, things get painful: skin and internal lesions occur as tissues separate due to unsynchronized growth. Fully blocked "pipes" lead to necrosis, suffocation etc. Plant life collapse under their own weight or die from malnourishement as their most exposed elements - leaves, flowers and fruits - grow faster then their stems/trunks and roots can carry or provide for. * Exposure to extremely high concentrations of life energy is horrifying, painful and fatal: tissues grow at rapid rates causing tears and fissures (think of bone growths developing in minutes or seconds, piercing through organs, muscles and skin). Organs function out-of-sync causing all sorts of mayhem to the creature (hormonal cascades, blood pressure so high it ruptures vessels and squirts through orifices, digestive fluids eating through the digestive tract etc.) - and weird, malformed and nonfunctional limbs and organs sprout all over the creature (and inside it...). Worse of all, at this level of life energy, a creature can survive longer than usual - prolonging the torture. --- 2: This covers digestive tracts, respiratory tracts and blood vessels in vertebrates, sap tracheids in plants, breathing trachea in insects etc. [Answer] ## Because fresh food is healthy but rotten not Why eating meat or vegetables give us nutrients but when we eat them rotten we get sick due food poisoning? The same applies to mana/orgone, their rotten state damage the environment. ## Because drinking water is healthy, but much drown you You said that rotten mana condenses into a thick and dense cloud, that means the concentration of mana increased a lot. Drinking a glass of water is healthy, but how about drinking 10 gallons of water? Amount matter, too much water can drown you or [water intoxication](https://en.wikipedia.org/wiki/Water_intoxication). Mana could be like oxygen. Oxygen has [free radicals](https://en.wikipedia.org/wiki/Radical_(chemistry)) and produces [ROS](https://en.wikipedia.org/wiki/Reactive_oxygen_species), both things produce damages in our mitochondria, DNA and proteins. Normal doses of oxygen aren't a problem, but elevated ones can produce [hyperoxia](https://en.wikipedia.org/wiki/Hyperoxia): > > Associated with hyperoxia is an increased level of reactive oxygen species (ROS), which are chemically reactive molecules containing oxygen. These oxygen containing molecules can damage lipids, proteins, and nucleic acids, and react with surrounding biological tissues. The human body has naturally occurring antioxidants to combat reactive molecules, but the protective antioxidant defenses can become depleted by abundant reactive oxygen species, resulting in oxidation of the tissues and organs. > > > That increases the risk of cancer, which explains why higher doses of mana grow sickly and weak plants. Maybe mana is radioactive, like [banana radiation](https://en.wikipedia.org/wiki/Banana_equivalent_dose), but higher ones are risky. [Answer] Mana represents the inherent strength of life, not the benevolent "life" we've come to accept is natural The way I can see this working is that mana is condensed "competition" and survivability, pushed to the extreme. If you have too much of it in a given place, it's not "more unicorns, rainbows and positive energy", it's more "a predator ensuring the survival of its litter by killing a prey" or "a prey developing a new defense mechanism to increase its viability". If you think of life as the positive energy in everyone, this won't work. You need to think of life as the strength that kept species alive, that gives people a "survival instinct", etc. Once you see it that way, it becomes easy to go one step further and pose the hypothesis that too much of that mana would be negative, as it would concentrate these negative energies of life in one place. Why are the creatures rabid and hostile? To ensure their own survival. Why are some trees growing sickly? Because the concentrated mana made sure other (likely stronger) trees were being too greedy and keeping all the nutrients/sunlight. [Answer] Parasites - Mana is not an entirely physical substance, but also has a magical aspect. This should pretty much go without saying, since "life force" has never been physically detected, let alone isolated. As a result, high concentrations of mana attract magical parasites, which feed on the local abundance, and this has at least two possible drawbacks. 1) In devouring mana, the parasites also diminish its availability to the local mundane lifeforms. This, of course, leads them to die. 2) As part of the parasites' "metabolism" they excrete byproducts which are toxic to the local mundane life forms. A good analogy here would be the effect of large quantities of bird poop on vegetation - it damages them due to the chemistry of the poop. [Answer] Unclean spirits Mana is supposed to cycle. When the cycle is arrested, the mana is stuck and stagnates. Trapped mana is the unclean spirits or angry ghosts of legend. The mana, cut off from its cycle, manifests as a shade or evil force, increasingly corrupt and jealous of the of the world now denied to it. The unclean spirit might try to seduce people into joining it, or seek to sabotage the endeavors of life. It might possess a human. Mana cannot be destroyed. Trapped mana must be rescued - broken loose from its stagnant state, and a way opened for it to rejoin its kind and reclaim its true nature. The procedure requires special skills. [![Jesus demons](https://i.stack.imgur.com/3sHlG.png)](https://i.stack.imgur.com/3sHlG.png) <https://en.wikipedia.org/wiki/Miracles_of_Jesus#/media/File:Schnorr_von_Carolsfeld_Bibel_in_Bildern_1860_191.png> [Answer] Here is what popped into my head. it is a little simplistic but could be interesting. Life energy is the force of evolution Basically life energy/mana/whatever is force that pushes life forward. In normal amounts it sustains life and nurtures it. I.E. creatures live and grow and adapt and their life energy grows as they mature to their peak then declines as they continue to age. When there is too much life energy in one place such as the miasma, the abundance of mana causes rapid evolution and mutation (in a bad way). Think things affect by radiation. So things born in the miasma will deformed and weak. Things that enter it will start undergoing rapid mutation causing illnesses like radiation poisoning or cancer, so things that enter the miasma will be weakened, become sick, and or die. Hope this helps. [Answer] ## Life energy is a narcotic Life is drawn to life, and pure life energy draws that much more fully. Birds, insects, even bacteria find themselves drawn to it. People feel a subtle calling, a longing, and a sense of connection that once was lost but could be found again. At low levels, life energy can be make an area seem blessed. Community and commerce flourish and people prosper. An area might simply seem trendy but it is in fact an area where the residual life energy is abnormal. As levels grow higher, people start to become drunk on it. Their sense of contentment creates laziness, lethargy, and filth. The bourgeoisie will leave, but the working men and women of the community stay, addicted, eventually becoming catatonic and lifeless. Meanwhile, the plant and animal life that had be drawn to the area will have drained the ecosystem of resources, causing a mass extinction event and leaving the area barren. [Answer] It would depend on whose life energy becomes this toxic miasma. # Only bad people Mana, or life energy, reflects the soul in death as it was in life. If a person's soul was especially toxic, the mana would reflect that as it takes form into a miasma. This life energy would be life energy in name and name alone. # Only GOOD people "Too much of a good thing is bad for you." We see this with a lot of things in real life. Water, oxygen, passion, money... It doesn't matter what it is. If you have an excess of something, eventually it will kill you no matter how safe it supposedly is. # A random selection of people There may be a common variable these people have that resulted in this malignment with their mana that people have yet to notice. In nature, nothing is random. Maybe souls (or life energy) have a code like our bodies do and there is a genetic disease within the life energy that leads to corruption? Maybe the cause is a disease that infected the person's physical body and it corrupted the soul? Maybe the poisonous Life Energy is bad because the life energy had been breaking down over time due to the strain of the reincarnation process and this is just the natural end all life energy clusters eventually see as they become inevitably unstable? Maybe it's due to an incompatibility between the life energy and its vessel, sort of like how a transfusion could be rejected by the recipient or how someone's body may reject a transplant? Maybe the guardian force responsible for protecting the source of all life energy found a reason to reject that "soul's" return? These are all possibilities you can feel free to work with. [Answer] Life turns low entropy systems into high entropy systems by feeding off of energy and replicating more energy feeders. In fact, life is the most efficient mechanism at this process, by definition. From this perspective, life kills the universe as if it were a parasite hastening its host's death. [Answer] When any living creature dies, it begins to decompose. This is accomplished through the presence of microbes and the occasional scavenger. Even a corpse left entirely alone by wildlife will rot away into dust and bone. For those microbes, a corpse is not a place of death, but of life-giving nutrition. Though we may find the process disgusting, it is an important process in returning our resources back to the environment. The reason that we often find corpses revolting is similar to the reason we often find spiders and snakes revolting - they present a deadly and often unseen threat to our own well-being. Many of the microbes that aid in decomposition would be almost as happy feeding on a living creature, and thus a corpse can also become a source of plague and disease. Thankfully, we can typically avoid such consequences by burying/burning the dead or by simply avoided any carcass that we find (don't go poking at days-old road kill). In our own history though, we have seen some intense examples of deadly microbes lingering near corpses. In particular, I am thinking of the fabled curse of the Egyptian mummies. On a few occasions, archaeologists entered ancient tombs of long-dead Egyptian rulers, disregarding the idea of a curse as mere superstition. To their misfortune, they discovered that the curse was not entirely a think of myth and legend. The microbes contained within these tombs had been sealed there for thousands of years, and they proved incredibly deadly. The first explorers to open and enter these tombs would often find themselves eaten alive over the next few weeks by this deadly but invisible threat, as if they had indeed been cursed for opening those tombs. The reason this "curse" existed was that these microbes did not have anywhere to disperse. I don't know how they survived so long, but they did, and the condition of being sealed away in a tomb in a dry, arid desert was apparently the perfect environment for them to grow and thicken. Considering that this life force, orgone as you called it, is essential to life, I cannot imagine that there wouldn't be microbes that feed on it. And, similarly to the Egyptian tombs, I'd imagine that your world would have certain conditions that could cause these microbes to linger long after they'd normally be gone. This in turn would prevent the orgone from ever being dispersed into the environment at large, resulting in an usual concentration of the stuff. It's not too far a leap to guess that this condensed orgone could make this microbe unusually active, causing it to attack the living as well as the dead, much like with those unfortunate archaeologists... As for what conditions might cause this... sealed tombs as described above might work, but anywhere that life can stagnate might work too (think fetid pools of still water, swamplands with no water flow, or anywhere that a pile of exposed bodies, whether from ritual sacrifice, murder, and natural disaster, is left to rot). [Answer] This is a slightly different example that those given by others. In fact, there is a real world example of this type of effect. Picture a cow pasture with beautiful grass and healthy cattle. A healthy cow walks by and drops an extra-healthy cow pie and continues on her way. Now focus on the cow pie and fast forward a bit. The cow pie is an excellent source of fertilizer and the grass in the nearby area will benefit from that and grow thicker and faster. However, this extra growth will actual be in a ring around the cow pie, leaving the central area with grass that is stunted or even dead. The amount of fertilizer at the source of this cow pie is actually too concentrated and "burns" the existing plants there. Eventually environmental effects will dilute and distribute this excess elsewhere allowing the location to recover. ]
[Question] [ This is possibly not quite the right place to ask this question but it's fundamental to the world I'm working on so here it is; if faced with a potent existential threat, in the form of an outside force, how will the human race respond? The current scenario I'm working on looks a bit like this; humans are massively out numbered and hugely outgunned but in no way surrounded by, or even in frequent contact with, an alien race with which they can communicate but generally don't, because one sided conversations are boring. This alien race basically ignores the human race beyond securing their frontier from human intrusion, a thing humans can't begin to do in return. The frontier is static this race hasn't advanced in our direction since they became aware of us, but no-one knows if that's by chance or design, afraid of provoking a forceful response human colonisation in that direction has also ceased. So the basic assumption I've been making is that if faced with a superior force that has shown it could destroy the human race, but doesn't, a de facto state of cold war would exist with humanity scrambling to build and spread to match their apparently unmatchable adversaries. I've made some accessory assumptions about large scale economic structure etc... based on this, and some setting shaping future history, but the underpinning of those assumptions is based in a response I'm beginning to wonder about; that being that the human race would, largely, stand its ground when faced by an alien race that is comprehensible (we understand them to communicate and more importantly the motives that appear to govern their actions), active (ambassadors "at court", open but generally quiet lines of communication), unfriendly (they don't talk much, won't trade and don't allow humans on their territory), non-belligerent (don't attack), but imminently and demonstrably capable of snuffing humanity out without breaking a sweat (they've vapourised everything that's ever crossed the border uninvited instantly). Any examples from fiction or even better history would be most welcome here since the model I'm working from is essentially the Cold War, but that was a contest of more-or-less evenly matched opponents where this is as asymmetric as it gets. [Answer] How scared are we? The threat isn't what causes the unity, it's the fear. Governments are now more or less responsible to their people. If lots of people are scared they do lots of stuff, if few people are they do much less. Do you think about the sun reaching out and burning us all? Or an asteroid smashing us. Some people who do guess the chance might be as high a 1% a year. Nothing much has been done. Terrorists and airplane crashes are not an existential threat but they do scare a lot of people and do generate a fair amount of cooperation between governments. Or global warming. There is doubt and disharmony at every level about the best course, the costs and who should pay them. Some people are really scared, and some are completely unconcerned. I would guess this is the best example for inscrutable aliens, since doing anything might trigger reprisal, so any particular thing needs to be consented to by at least the powerful nations. Some people already suggest we probably ought to get out of this here hole and billions of dollars support various visions. If more people agreed more strongly we might make faster progress, if a powerful nation forbid it we might be set back pretty significantly. [Answer] "if faced with a potent existential threat, in the form of an outside force, how will the human race respond?" Especially if contact is infrequent, I think we'd go about our lives as normal, quashing our fears with denial and inaction. My feeling is that we'd rapidly be rent by division over whether the existential threat exists at all, with the denying side insisting that those aware of the threat are conspiracists, alarmists, and/or trying to steal their precious bodily fluids. I think we'd continue to deny, shift blame, invent elaborate conspiracy theories argue, and whine until motherships were hovering over world cities with weapons hot, and maybe even for a while afterward, and at that point I think we'd phase-change and pursue a half-cocked, belligerent, and fearful strategy borne out of the collision of panic and short-term self interest. While realistic, I think that would be an unsatisfying literary scenario, if for no other reason than being a bit too on the nose. [Answer] What makes this question relevant to Worldbuilding SE is that it concerns what strategy would be adopted by the human species in face of an implacable, vastly superior alien civilization that is quite annihilating humanity but refrains from doing so while remaining within its own borders. The querent has suggested a de facto Cold War situation exists between the aliens and humans. The Cold War was a competition for dominance between two global Super Powers. It was a contest for ideology, political influence and economic control of resources. The situation with the querent's aliens seems more than like of Traditional China, before the nineteenth century, where China was a massive self-sufficient economic, social and political empire that needed virtually nothing from the rest of the world. There are comparisons with Japan of the Meiji era. But this seems to be the reverse of that, where humans are playing the role of a Japan ignored by the rest of the world and fearful about when the black ships will arrive. It sounds like the humans could simply continue with their own affairs and ignore this potential existential threat. However, it can be expected that wiser heads will prevail within the inner councils of government, academia, political and economic institutions. They will ponder how the human species can thrive and survive in a future that could easily be blighted by the slightest hostile move from the superior alien civilization. There are several strategies they can adopt. Expand human territory in directions away from the alien sphere of influence. Engage in a massive program of research and development to implement, eventually, weapons, vehicles, communications, power systems, and whatever else technologies are necessary to make the human species capable of standing against their erstwhile potential alien superior adversaries. Send emissaries to the alien systems to learn more about their civilization, culture, science and technology, and generally act as ambassadors. If nothing else, this will enable humans to accurately gauge the risk potential of the aliens. if it turns out, the aliens genuinely perceive we are of no threat potential to them and they are truly unlikely to act against our species so much the better. There is one caveat to this set of combined strategies. If the aliens didn't see our species as a threat and we then developed the technology to match their capacity and capability this might change to our detriment. Once we can match them humans are now a threat that need to be stepped on. Wars usually break when neither side knows which of them is the superior militarily. When one adversary is clearly superior, the other naturally will avoid open conflict and warfare because they know they will lose. The greater proportion of the human population will be unconcerned. The existential threat is remote from their normal affairs and they will get on with their lives. In summary, do not antagonize a superior foe, potential or otherwise, but take sensible precautions to prepare for your long-term survival. [Answer] People won't care. At least, most of them will not. Most people do not enter resistance when their country is invaded, most people do not bother about damaging their ecosystem. As people eventually die[citation needed], they focus on self-preservation at an individual sort-term level rather than on a long-term global level as a specie. This self-interest implies that unless their very daily existence and comfort is threatened, you can expect that nobody will really care. People will continue their business as usual. If they can make money with your threat, it will even be better. Expect a few extreme behaviors from a minority that will not be happy with the mental pressure caused by the situation, and maybe some superstition, myths, or religions about this new threat. And finally, expect politics and people in situation of power to gather as much information on this threat so that they can use it for their interest. The underlying actions and competition may even cause the initially friendly aliens to react. [Answer] In real life many small groups of hunter-gatherers numbering from tens of thousands down to tens of persons have been in contact with much more advanced civilized nations and empires where each man was more militarily powerful than a hunter-gatherer warrior and the population outnumbered the hunter-gatherers by hundreds, or thousands, or tens of thousands of times. From what little I known, the hunter-gatherer populations usually did not spend all their lives in fear of what the more powerful societies might do to them. In fact, a few such situations may exist at the present time If so, a researcher could ask some of those hunter-gatherers how much they worry about attacks by the more powerful society. In fact, members of the less powerful society might not be able to comprehend how much more powerful the other society is. I once read a story about an Apache delegation to Washington, DC about 1876. The Apaches decided to count each white eyes they met on the journey, but they ran out of numbers. Then they tried to count each white eyes house that they saw, but they ran out of numbers. Then they tried to count each white eyes village they passed, but they ran out of numbers. In a big city they looked out the windows of their hotel room at the crowds on the sidewalk below. They thought that there couldn't be that many people in the world and they must all be walking around the block over and over again. And when they got home and told their story, the other Apaches didn't believe them and claimed that the white eyes must have cast a magic spell on them to make them see illusions, or so goes the story. In the pilot episode of Buck Rogers in the 25th Century (1979-81), released as a theatrical film in 1979, it is said that Draconian Emperor Draco the Conqueror is very eager to open diplomatic relations with Earth and/or to conquer Earth. It is also said that Draco has conquered half the universe. Would it really be a great "feather in the cap" for Draco to open diplomatic relations with Earth or conquer Earth? Would it be a great achievement for the President of the United States to open diplomatic relations with Monaco or conquer Vatican City? The difference in the importance of the two realms is far more extreme in the case of the Draconian Empire and Earth in Buck Rogers in the 25th Century (1979-81). If Draco has only conquered half of our galaxy he would rule about a hundred billion solar systems and have Earth outnumbered billions to one. And if Draco has conquered half of the universe he would rule billions of galaxies. But most members of the educated audience of Buck Rogers in the 25th Century (1979-81) didn't scoff at the idea that Earth could be a prime target of the Draconians, because to most Earth people Earth seems at least as important as every other planet in the universe combined. So I guess that most future Earth humans in the OP's scenario will not be too worried about the all powerful aliens known to exist. They will subconsciously think of Earth and its solar system and colony planets as equal to the rest of the universe combined. [Answer] Referencing first 9/11 and then climate change, I would predict an initial panicked response, calling for lots of action - perhaps the creation of pan-terrestrial government with military powers. After a while, as nothing happened, people are very good at ignoring the really big, long term threats (like climate change) in favor of the local, personal and immediate. However, in your world, people who get power from focusing on the distant threat will try to keep it so that might change the dynamic if you have powerful people with an incentive to foment fear in order to keep themselves in power. A fictional example (I think) would be Game of Thrones where most of the characters are focused on the politics of the known world and fighting between themselves while only a few are paying attention to the very much larger threat just beyond their walls. [Answer] If the aliens can destroy us if we stray into their territory but otherwise leave us alone, then there is no existential threat. Humanity will erect a "There be monsters here" sign, and go on. That is unless there is some resource in their territory that we believe we need badly enough for intrepid folks to risk incursion. If after each incursion, the aliens respond by taking out a city or outpost, humanity would demand their leaders to do something. The more frequent the attack, the more focused humanity would be. Just seeing technology used would focus research into that which we already know is possible. So I would imagine we would start to catch up a bit (like the Native Americans [adopting the horse](http://www.equitours.com/views-from-the-saddle/article/the-horse-and-native-american-culture/), or when Japan transitioned from using straw horseshoes to iron, after seen European horses with them.) ]
[Question] [ Let's say the city covers about 40 square miles (104 square kilometers), that machinery and some oil refineries are still usable (for construction vehicles), and that there is a lot to salvage in way of constructing walls. In addition, let's say one would have to be athletic to outrun infected humans. The intended city is the remains of Simi Valley, suburban sprawl rather than a concrete jungle like Downtown Los Angeles and surrounding regions. Infected humans have a sense of numbers, time, distance, and self-preservation; they can learn from observation; and they can use tools, crude as they are and limited by their physiology, provided someone is insane enough to capture infected. Nonetheless, they aren't silent hunters and are limited in their cognition. Basically, they're comparable to the infected in the I Am Legend film; they can use traps but wouldn't devise one without first witnessing one. Would it be sensible to build a wall around the entire perimeter, or would it be more sensible to set up outposts outside the perimeter, wall off a number of sections in the city, and reinforce buildings outside the sections to be used as [pillboxes](https://en.wikipedia.org/wiki/Pillbox_(military)) of a sort? The wall(s) is mostly to keep them out rather than humans. Update: Your responses made me reconsider some details in my world--for the better--and are therefore appreciated. [Answer] This depends entirely on your city. * If it's miles of suburban sprawl with wide gaps between houses and large gardens, forget it, go somewhere else. * If it's close and neat grid aligned tower blocks then you just have to block the spaces between the towers and you're done. That's a lot less work than the 20+ miles of wall you have to build otherwise. What you really want to do is abandon the city, where all the people were and hence all the zombies now are, and go out into the deep countryside where the people weren't and hence there aren't any zombies. If you want to build a wall around a city after a zombie apocalypse, it's to keep the zombies in not out. [Answer] A wall is as good as the men (and/or women) defending it. How many people is living there is going to be the deciding factor on wall's size. If there are too few, a large wall is a liability. The enemy can disguise its movements and make a sudden attack on a specific point of the wall, the defenders won't make it on time. If there are thousands of people, you need a lot of space for them, and thus it may be a good idea having a wall which protects all your inhabitants instead of just an elite of them. Even if they all gather in a fortress, having to abandon their houses and farms to the enemy is going to take a toll on their moral - and on your supplies. However you say something about "outrun infected humans". If we are talking about a sort of zombie apocalypse, we can more or less safely assume that the enemy is not intelligent nor capable of using machinery, and then, the principles still stand, but they can be more relaxed. [Answer] Realistically, in a post apocalypse, cities would probably be abandoned. There is no source of food in cities, once whatever was on hand runs out, and no way to make food. I don't have a link to exact figures, but I believe that without resupply (which would probably be the case in a post apocalypse scenario), the average large city with half of its population intact would run out of food in around three to four weeks, probably sooner for the majority as the few that had access to food stocks would hide/hoard them. Also, fresh water would begin to run out if the water plants were not operating. This is one of the flaws in apocalypse style films that have survivors staying in cities. That is a Hollywood invention, to put the protagonists on ground that is familiar to the majority of viewers. Most likely, the survivors would head out into the country, where subsistence food may be obtainable: game, crops. Also, survivors would be more likely to find a steady supply of fresh water in the countryside than in a city. [Answer] Building walls take time that you probably don't have a lot of when being beset by the infected. (Depending on the severity of you apocalypse, but I guess we're talking the standard zombie 70-90% of the population here.) But sensible? Yes, definitely. As long as you subscribe to the theory that people get together under pressure and cooperate in a crisis. Walling in your living space and farmland makes it easier to keep safe and frees up resources that otherwise would have to be spent on defense. You could feasibly start off with smaller separated enclosures that gradually grow and connect with each other over the years to produce something like what you want over the years. As long as the infected don't master siege weaponry or the art of ladder-making the inhabitants should be able to live inside their fortress with regular patrols along the perimeter (cleaning out anything that could be used to climb the wall such as huge piles of corpses and making sure there are no weakenings or breaches). My money would be with one of the European cities who still have more or less intact medieval walls though. Such as [Saint-Malo](https://en.wikipedia.org/wiki/Saint-Malo) intra muros or [Visby](https://en.wikipedia.org/wiki/Visby). (Make mental note: write a Zombie apocalypse story set in Visby before someone beats me to it...) Because building a pallisade or surrounding yourself with chain link fence is one thing. But when it comes to non-siege warfare nothing beats a ten meters high stone wall, and those take time to build. Considering what you've told us about the infected I suppose a spike filled moat could be carved out with access to the proper digging tools and then you can errect barbed wire and chain link fences to get a first defensive perimeter. But it is risky work while being onset by hordes of ravenous zombies. You'd have to figure out a way of protecting the workers who will no doubt attract a lot of unwelcome attention. [Answer] It is very viable in some circumstances, not at all in others. Your question is very unspecific and broad so one could easily write a book about it, but consider some things: a) If you have city states that do trade with each other and have different legislation, over all a low level of cooperation: walling a city could be very useful to ensure you know who enters your city so you know who has to pay what fine for entering and in order to capture criminals and so on. A city wall in that case would be mainly used to ensure everyone knows where a city ends. b) If hand guns are still available, a city wall becomes counterproductive. One of the best ways to defend a city with modern hand guns is to let the enemy into that city and hide in the houses instead of letting him know where you are (on the city wall, right there, I can see you and now you are dead!). I'm sure you've encountered the concept of urban warfare before. c) If you have enemies, and it sounds like you do, that get stopped by a wall, of course a wall is a good idea, but one should look into other, more cheaper and maintainable solutions such as fences. I think details are needed to tell you how well a city wall would do in your world specifically. In any case, I would advice against walling an entire city. Just wall the bare minimum of space. So I guess the answer is always no - only parts of a modern city. As for details how to use houses in your wall and so on, just check out the Berlin wall. It's a mediocre example because the post-apocalypse (whatever that may be) has very different demands and resources available, but they build a wall in a modern city ... [Answer] What good is a wall against an omnipresent threat? Castles only worked because 99% of the time, you could freely leave your castle or let people in; which you would need to do to get food from farms in the surrounding countryside. Castles would often stockpile food in them so that some people could hole up in the castle for a year or two before they run out of food. But that's how sieges worked. You surround a castle and don't let any food get in until the people inside starve to death. If zombies are going to be around for long enough that you've got time to build walls, then it's too long to just hole up in a small walled city. How are you going to protect your farmland? [Answer] You will need a city, and you will need farmlands. The city needs to be as compact as possible. Select a number of city blocks with enough living space for your survivors, block all the roads, block all windows and doors on the outside, add barbed wire, demolish any nearby buildings to have a clear line of sight, post 24/7 sentries on rooftops, and you are more or less secure. But that's just your city. The city needs to be fed. So you need a much large area next to your city, which would be much more difficult to secure properly. You can build a perimeter fence, but you can't make it as big as city wall, and you can't watch 24/7 every yard of it. So assume your farmland is not very safe, and any people venturing there would have to take appropriate precautions. [Answer] You already have walls. Because even before zombies people didn't like other peoples wandering through some important sites like refineries and factories [![enter image description here](https://i.stack.imgur.com/qjjgm.jpg)](https://i.stack.imgur.com/qjjgm.jpg) So we make walls around them. Or fences. If these sites are close to each other we build footbridge. If they are far apart we build tunnels. If you are in post soviet countries your factories usually have even bunkers. It's easier and more energy efficient to find good spot and adapt it than to totally convert chosen spot to your needs. [Answer] The real question is why? Fortifications went out of fashion in the 20th Century because weapons development rendered them obsolete - however they are becoming notably prevalent in low-intensity conflicts. Walling will therefore really depend on the level of weaponry in your post-apocalyptic world - if equipment such as aircraft or heavy armour still exists then they won't really help, if you're just up against small-arms then there's much more utility in walling things in. It is also worth considering the alternatives to walling; mines in particular may be an effective way of keeping people out. [Answer] A 40-square-mile city would have a perimeter that is 25.3 miles. If there were a relatively small number of human survivors in this city, and only a smaller subset of them were helping with the wall-building effort, and they had only post-apocalyptic resources at their disposal, I would have to think that it would take several years to build this wall. So a few questions arise due to the multi-year nature of the construction process... -If these carpenters could survive for years before the wall gets erected, and furthermore, survive despite the vulnerable position of erecting a wall while under attack, then couldn't they just survive without building the wall at all? -If these carpenters can avoid getting eaten for years while building the wall, then will the zombies still be around years later? Who will they have been eating during the passage of all of these years? Might they zombies have spoiled and died of starvation if they go years without eating? I think a more sensible approach might be to just seal the alleyways between a few buildings in a 1-block radius and perhaps give it a guarded passageway that is advantageous for defense. [Answer] The problem is to protect your survivor population both during the initial outbreak, and provide security for long term survival. You also must plan for sustainable supply of resources. Assume that you can both identify survivors, and that you have sufficient resources to protect survivors during the initial hot contagion period (food, medicine, ammunition, et al). And assume that your leaders have both the foresight and the political willpower to enforce the necessary changes to preserve the citizens. Initial protection period could be bootstrapped using existing police and soldiers, firefighters and construction crews. Assuming you have access to sufficient resources, you would assemble emergency barriers, choosing strategic locations to erect temporary barriers, leveraging existing buildings to provide part of the natural fortifications. The erection of barriers would proceed simultaneous with demolition of buildings and obstacles outside the barrier to enforce a kill-zone 200-1000M wide around the safe zone (how fast do your infected move?). Since the threat is low-tech (infected, low speed), you would likely need to erect a barrier between 12-20 feet high. Temporary fencing would suffice for some areas (short term), but would require constant vigilance from defenders. Chain link is too easy for infected to scale. You need entrapping obstacles in the kill-zone. As the initial situation stabilized, you would continue to reinforce and improve existing barriers and erect new barriers. You could quickly erect walls around parts of the city using existing semi-trailers and train boxcars. These obstacles could be installed as quickly as the survivors could drive or haul them into position. This initial barricade may only be 8-10 feet high, but augmenting the barriers with a 3-4 feet high battlement would protect the survivors from contact with infected. Once the initial onslaught of infected has been resisted or repelled, ongoing fortifications could be constructed by trenching and obstacles in front of the walls, and as time and resources permits, combining demolished rubble with concrete to pour more effective walls. Remember, the threat is from infected, who have been reduced to primitive weapons (no guns or munitions). As the walls continue to improve, the trailers and boxcars can be dismantled to provide metal sheathing for the walls (again, no explosives being employed by threat). Your initial city may have irregular shape, due to exigencies during initial fortification construction. During this stabilization period you would correct the perimeter to the best shape, especially as the barriers grew more effective. Guard towers would be erected to provide enfilading fire from height (again, no snipers amongst the infected). And you would also have no threat of engineers or sappers from the threat side to tunnel under your walls. All of the classic problems with walls - explosives, siege weapons, munitions, sappers, trenchers, engineers - pose minimal challenge. The infected are a threat that does not pose serious problems to the classic weaknesses (other than needing distance and firepower). Walls need not address the myriad weaknesses that normal external threats pose. Think about the siege of Stalingrad as an example here. Assume that the food, medicine, and ammunition challenges have been managed to this point, then you need to ensure that you have sustainable food and water supply, sewage, and industry. Cities are often located near water and sewage, and we could assume that a nearby power generation (hydroelectric, nuclear, geothermal, or solar) could supply sufficient energy for the security lighting, and reconstruction efforts. Food is the problem. You cannot grow enough food inside the city walls to feed the population. The land is likely not sufficiently arable, the livestock was not kept near the city. You have too many people for the land, and you need enough people to guard the walls 24x7, and provide all the industry you need to sustain the city. You could assume enough recycling efforts to provide materials, and your city might be located near a quarry or mines, providing ample natural materials close at hand. What you really need are natural barriers. You need barriers provided by harsh or impossible terrain. Think the cliffs of Dover for example. Typical cities are located on rivers, at ports, with very little natural terrain providing defenses. Other than buildings there is little to impede the leisurely stroll to approach many modern cities. But San Francisco, Manhattan, or Long Island have limited access other than by water. Can you identify a city that provides natural barriers on two or three sides? Could you devise a way to make the water a natural defense to the infected? Identify those cities which have substantial natural barriers, and your survivor cities would only need a fraction of the defenders that a city requiring a complete wall would require. Perhaps your city is located on a natural rise, and you can engage earthmoving equipment to cut a 20-50 foot high wall (faced with metal sheathing) around large parts of the perimeter. Perhaps the infected cannot swim, and water prevents their approach. [Answer] It depends mainly on the plan for the city. If it just a minor stay or you plan to strip the city of useful stuff before departing forever, outposts with some strong pill boxes will do fine. But if you plan to make this back into a functioning human settlement in a zombie world a wall is a must. With the looming axe of death at anytime by a zombie who may have slipped through the outposts, peoples work ethic and moral would bottom out. So even if they had factories or farms to work at, no one would go, especially after one or two braver people went and died that way, which would cause even more internal problems. A wall provides security to a populace within. But building a wall around an entire city it too much all at once, it would have to be done in stages. Either expanding out from a central point, each new wall is built further out capturing more of the city and land for use at each completion would be a good way. > > > ``` > +-------------------------------+ > \| 3 \| > \| +--------------------+ \| > \| \| 2 \| \| > \| \| +------------+ \| \| > \| \| \| 1 \| \| \| > \| \| +------------+ \| \| > \| \| \| \| > \| +--------------------+ \| > \| \| > +-------------------------------+ > Or > +-------------------------------+ > \| \| \| \| \| > \|-----\|----------\|---------\|----\| > \| \| \| \| \| > \| \| \| \| \| > \| \| \| \| \| > \|-----\|----------\|---------\|----\| > \| \| \| \| \| > +-------------------------------+ > > ``` > > Something of the like, morely just extending the city boundaries a step at a the time to disperse the population into more useable space. But how much and how far are all dependant on the amount of people. So to sum it up: If you are making this city into a place to call home, make it secure! [Answer] I think you can look at real life examples of walling off large areas/cities: * [Berlin Wall](https://en.wikipedia.org/wiki/Berlin_Wall) * [West Bank Barrier](https://en.wikipedia.org/wiki/Israeli_West_Bank_barrier) * [Hungarian Border](https://en.wikipedia.org/wiki/Hungarian_border_barrier) * [Indian Line of Control fencing](https://en.wikipedia.org/wiki/Line_of_Control#Indian_Line_of_Control_fencing) These walls are all designed to keep out humans, but will work just as well on large wildlife and zombies. They are all at the kind of scale you are looking at. Their construction has been usually under adverse circumstances. By most metrics, they did their job. They are expensive in manpower (constructing and manning) but mostly low-tech (mines, some lights, sensors), and reasonably low maintenance. Given these examples, I'd say walls are pretty well proven, and an efficient way at reducing the surface of potential attacks. [Answer] Why would you? If we take the population density up to that of New York City, then your city could support a million people. But where do you get food for a million people post-apocalypse? Rather than walling off forty square miles of city, wall off less than a square mile of town and a much larger area of farms around it. So the central area is defensible at night while the larger area can be cleared and defended during the day. You want the entire larger area to be within an hour or so of the central area. So people can leave the central area and reach the outskirts of the larger area in a reasonable commute. That gives you a larger area of around thirty square miles (assuming a walking radius of about three miles). You wouldn't want to start with a city for this, as the city will have paved over the good growing area. You'd be much better off starting with a small town (or even something like a hotel with a few supporting buildings). Houses and city infrastructure are easy to find. What's hard to find is food. For the kind of small communities that you'd actually have, you don't need a city. If you were in a city, you'd need to leave before you had time to do things like build walls. [Answer] It really depends on your type of zombies. Slow shamblers can't get past a chainlink fence but the ones from "I am Legend" were perfectly capable of climbing and the zombies from ["World War Z"](https://www.youtube.com/watch?v=HcwTxRuq-uk) swarmed over walls through shear numbers. In ["Wayward Pines"](https://en.wikipedia.org/wiki/Wayward_Pines) they used a wall topped with an electric fence to stop them climbing Most likely you'd run a wall as well as reinforced buildings inside to provide a refuge and a pillbox should the wall fail. If too aggressive for a wall, it would have to be underground linked pillbox defenses ]
[Question] [ The drug should have the same effect as heroin, but without being addictive at all. Is this chemically possible? [Answer] [Larry Niven's Known Space writing universe](https://en.wikipedia.org/wiki/Known_Space) included a device called a [Tasp](http://larryniven.wikia.com/wiki/Tasp) which induced electrical signals inside the pleasure centers of the human brain. It's effects were described as overwhelmingly euphoric, rendering the "victim" so flooded with pleasurable sensations that they could not perceive or interact with their real world surroundings. Such a device did not involve any chemicals being added to the brain, but it was described as being extremely addictive. It is my belief that this is a fair prediction of the addictive properties of anything that makes us feel as good as heroin apparently does. It does not matter if there is any chemical cause for the addiction, our simple desire for the continuation of that sensation can enslave us as strongly as any drug. If your chemical-addiction-free heroin substitute has the same effect as real heroin, we will become addicted to those effects regardless of the chemistry. [Answer] Absolutely, it would be addictive, because what you're talking about is messing with brain chemistry. I think that perhaps you might be confusing two different things: Dependence happens when the body has adapted to the continued presence of a drug Addiction can be bound up with dependence, but it doesn't have to be. With addiction all that needs to be present is a persistent compulsive use of a substance or action known by the user to be harmful to their lives and/or bodies Anything that's pleasurable can be addictive. Some of addiction has less to do with physical withdrawal and more to do with brain chemistry. A certain number of people are [predisposed to addiction](https://en.wikipedia.org/wiki/Addiction_vulnerability) through genetics, the age at which they tried drugs (the earlier, and more frequent the more likely to have the pattern), and the environment. You might think that with no physical withdrawal symptoms that it's not actually addictive. I disagree. Because anything that messes with the pleasure centers has an effect. > > When stimulated by amphetamine, cocaine or other addictive drugs, the reward system disperses up to 10 times more dopamine than usual. > Continuous use of such drugs robs them of their power to induce euphoria. Addictive substances keep the brain so awash in dopamine that it eventually adapts by producing less of the molecule and becoming less responsive to its effects. As a consequence, addicts build up a tolerance to a drug, needing larger and larger amounts to get high. In severe addiction, people also go through withdrawal—they feel physically ill, cannot sleep and shake uncontrollably—if their brain is deprived of a dopamine-stimulating substance for too long. [SOURCE](https://www.scientificamerican.com/article/how-the-brain-gets-addicted-to-gambling/) > > > The source I have quoted above is an article from Scientific America on GAMBLING addiction. Please do click on the link and read the article, it is simply chock full of info you would find useful regarding the subject of addiction and how it works. The article, which is worth reading, basically talks about how initially a gambling addiction was just thought of as a bad habit that could ruin your life rather than bona fide addiction. But they have found that the same sort of therapeutic treatments and approach used to beat addiction, and the same brain chemistry issues are present in those who can't stop gambling. You might say "hey not gambling won't give people physical symptoms when they don't so it doesn't count as a addictive." To which I say, for a certain segment of the population it absolutely is. Furthermore, gambling, which is something that involves no drug at all, can change brain chemistry and response in the same EXACT ways drug addiction does. > > A 2005 German study using such a card game suggests problem gamblers—like drug addicts—have lost sensitivity to their high: when winning, subjects had lower than typical electrical activity in a key region of the brain's reward system. In a 2003 study at Yale University and a 2012 study at the University of Amsterdam, pathological gamblers taking tests that measured their impulsivity had unusually low levels of electrical activity in prefrontal brain regions that help people assess risks and suppress instincts. Drug addicts also often have a listless prefrontal cortex. > Further evidence that gambling and drugs change the brain in similar ways surfaced in an unexpected group of people: those with the neurodegenerative disorder Parkinson's disease. Characterized by muscle stiffness and tremors, Parkinson's is caused by the death of dopamine-producing neurons in a section of the midbrain. Over the decades researchers noticed that a remarkably high number of Parkinson's patients—between 2 and 7 percent—are compulsive gamblers. Treatment for one disorder most likely contributes to another. To ease symptoms of Parkinson's, some patients take levodopa and other drugs that increase dopamine levels. > > > So what does this tell us? It tells us that if something gives us pleasure, it has the capacity to be addictive. You might be able to gamble and stop, no problem. There are people who were able to do heroin a few times and stop, periodically using again--but the rate of addiction for the drug is pretty high, even for those who don't have a predisposition to addiction. Let's take a drug though, that we have today that does stimulate the pleasure centers, but that has been claimed not to be addictive. [Molly](http://drug.addictionblog.org/is-molly-addictive/). [Ecstasy](http://www.drugfreeworld.org/drugfacts/ecstasy/can-i-get-addicted.html). [MDMA](https://www.drugabuse.gov/publications/research-reports/mdma-ecstasy-abuse/mdma-addictive). It's not supposed to be that addictive. There aren't really physical symptoms. But the brain can be completely changed. > > While many people do not develop chemical dependency on Molly, > psychological craving (the defining characteristic of addiction) can > be quite high. Molly effects the brain by altering the chemical > responses of neurotransmitters. These disruptions hinder proper > communication between neurons. > > > There are people, right now, who are on Molly just to function, not to get high, which is, of course, a big sign that they are an addict. Here's what I would do with your fictional drug to get to where you want: * It repairs/resets anything it damaged before it wears off. * The high is exactly the same every time. As in you don't need more of it to get high. No one builds a tolerance. If there is no tolerance, then folks are less likely to need it just to function. This is not chemically possible as of yet. Far into the realm of sci-fi, I would say. [Answer] I'd also say, the answer is No, "without being addictive, at all," is impossible because everything pleasurable is addictive. We have sex addiction, food addiction, exercise addiction, porn addiction, gambling addiction, gaming addiction, just to name a few that are legal and have been academically studied. Notice none of those are physically addicting (not even the food), but they all cause very similar (or identical) changes in the brain in terms of releasing endorphins. Heroin and cocaine are the masters of this release, but consider the proof by extremes here: We have people that are seeing and paying psychologists to help them break their sex addiction, which has any chemical component whatsoever, Because this is interfering with their work (repeatedly missing in action, late, distracted), their marriage (about to end, with custody hearings for kids), and their lifelong friendships and extended family life. Now as pleasurable as sex may be, rock stars and sports stars that can have all the partners they want, as many as they want at a time, *still* say heroin blows sex away in the magnitude of the euphoria. Chemical dependence is not the main feature of addiction, anything *just like* cocaine will most certainly be very highly addictive, and still destroy people's finances, relationships, and lives, still lead to the same lies, cover-ups, and crimes to feed the addiction. There is no way to make anything that is pleasurable "not addictive at all". [Answer] It's a tad ironic you asked this question today. The most popular (emailed) story at the [nytimes.com](https://www.nytimes.com/2017/06/30/opinion/sunday/what-cookies-and-meth-have-in-common.html) is about how all the intensely pleasurable activities (drugs, comfort food, sex, etc) are addictive, because they are pleasurable. It talks about the power of habit, but also the change the dopamine receptors in your brain, causing you to no longer be stimulated by less intense experiences. Now, you can be dependent on heroin to avoid withdrawal symptoms. But that's considered differently from addiction in medical literature. If you're asking if something can be that pleasurable without physical dependence, sure. If you're asking if something can be that pleasurable without being addictive, I don't believe so. [Answer] It seems like it would be most plausible if the user took a drug that prevents the addiction from forming. I'm thinking something along the lines of ibudilast. <http://www.huffingtonpost.com/2013/04/03/meth-addiction-cure-ucla-ibudilast_n_2863126.html> One could imagine a heroin user mainlining an anti-inflammatory drug or a biologic, or having a port that connects to either drug (or a saline drip to easily rehydrate). This could also open the door for some interesting conflict (addiction blocker gets stolen, user runs out without realizing it, someone maliciously replaces drug with placebo or other drug, etc). [Answer] Other answers have dealt with the difference between physical and psychological addiction. Physical requires repeated uses and a recalibration of the physiology such that the lack of the drug causes withdrawals. There are lots of examples of this and not all are fun - clonidine, for example, is a blood pressure drug. If you take a lot and the run out or go cold turkey you can suffer a surge of blood pressure. The withdrawals from opiates or alcohol are similar physiologic effects. Since there are several [opiate receptors](https://en.wikipedia.org/wiki/Opioid_receptor) and it is possible to have drugs which are selective inhibitors of specific ones (e.g. [methylnaltrexone](https://en.wikipedia.org/wiki/Methylnaltrexone)) you could theoretically have an opiate which conferred a heroin high without inducing dependence with repeated use. The other issue is psychologic addiction. If you crave the different feeling conferred by a substance or experience it might not matter what the substance or experience is. This would be a risk with the non-dependence opioid described above. All of this is in the other answers. The new piece here: the way around psychologic addiction is amnesia. If you do not remember how good it felt, you will not be thinking about it and craving it. There is some thought that the hormone oxytocin works this way (but in the reverse) as regards childbirth - if a woman giving birth clearly remembered how much it hurt, she might avoid that in the future and so decrease her genetic fitness. Those women who did not lay down memories clearly during the experience would be less likely to avoid it in the future. Short acting amnestics are used routinely for unpleasant medical procedures - it is bad for the person while it happens, but they don't remember afterwards. This is also the principle behind the date rape drugs. So: your no-addiction drug must lack the ability to cause physical dependence, and either itself or with a codelivered drug block the ability to lay down memories of the experience. [Answer] As others have said, since activities themselves can become additive for certain people, there's no way to totally limit the addiction potential. However, if the substance in question also had the effect after the high wore off of acting as an opioid-receptor blocker, then subsequent re-doses of the chemical would fail to achieve any kind of noticeable high. There are actually products on the market now that can block these receptors temporarily, but for the purpose of making the chemical TRULY non-addictive, there can be only one choice: Have a single usage of the chemical end with the complete disabling of all the opioid/amphetamine/cannabinoid/etc receptors in the brain. You can therefor only use this drug once, and while it can provide the greatest feeling ever, after it's over, you will never again have any other kind of high in its class of drug. This will have the effect of making the drug unappealing to some folks who feel the need to constantly medicate themselves, but would also open up the drug to a whole class of other "respectable" citizens who would otherwise be worried about addiction and would never consider taking anything that didn't have this baked-in buffer. Furthermore, if the primary effect of the chemical was a profound psychedelic experience, it could be used by existing addicts as a final "cure" for their addictions, since they'd have the duration of the drug for its primary effect to contemplate how their lives had gotten so screwed up, with the knowledge that they would now be unable to return to opioid/other abuse. This is similar to the real-world usage of ibogaine and ayahuasca to treat drug addiction. [Answer] Yes, I think so. Certainly you can speculate such thing being possible. Stories about "herbal remedies" that actually "reset" drug addiction do exist after all. Bad news is that since drug policy is such a sensitive thing research has been limited. Good news is that this also means we are free to speculate. The basic issue is that pleasure is the way brain uses to reward experiences that should be repeated so there is a hard-wired system that strengthens behaviour patterns that led to the experience. So pleasurable activities are innately habit forming and addictive regardless of the nature and specifics of the activity. The pleasure and and the habit forming are still two separate processes. So it is possible to have pleasure without it becoming addictive. Mental and physical state for example can reduce or increase addiction. Your hypothetical drug would simply contain an additional component that entirely blocks the habit forming process. This drug would be entirely non-addictive. Although it would be even more incapacitating than the unaltered drug. If the drug simply blocks or inverts the strengthening of the habit it would actually help reduce pre-existing addictions to similar drugs. [Answer] As others have said, it's pleasure that people can be addicted to, not so much a chemical. One study noted that 20% of soldiers in Vietnam were using heroin, but most quit when they came home. Another study showed rats preferring cocaine-laced water over plain, but a follow-up study showed that under different circumstances, they avoided the cocaine. [Quick summary](https://youtube.com/watch?v=ao8L-0nSYzg) based on [Chasing the Scream](https://books.google.com/books?id=DxAbBQAAQBAJ&printsec=frontcover). ]
[Question] [ Closed. This question is [opinion-based](/help/closed-questions). It is not currently accepting answers. --- Want to improve this question? Update the question so it can be answered with facts and citations by [editing this post](/posts/74471/edit). Closed 6 years ago. [Improve this question](/posts/74471/edit) I have some kids, some of them can use magic, how can they make enough money to live without stealing too much, maybe a bit of pickpocketing. Magic is illegal unless you work directly for a king or a duke, and the kids don't. Tech is medieval. This is how magic works: Magic runs in your blood. It is a second life source, and if you run out; you die. The less you have the weaker you get, it is also second stamina. They way your body checks if it is physically strong enough to do something is it checks if your body has enough energy, and magic. The energy gets used up, but the magic doesn’t. When you actually use magic that is different. When you use magic, you don’t need energy. Magic has two ways of doing something; on release, and on impact. If you were to light a fire, let’s say, and you wanted to do it with magic, you could either send out the magic, still in magic form, and when you hit the pile of sticks, you can turn it into the fire. The other way is to make a small flame that shoots toward the fire and lights in when it hits. Some spells can be both, but some are only on impact. If you send a spell to paralyze them, make them unable to move, there is no way, unless maybe sending a spray of paralyzing poison toward them, to do it on release. Also, everyone has magic. Some just produce more than others. This is the reason that few can do great feats of magic, though if they knew how almost anybody could conjure a candle-flame. Another thing that you had to know about magic is the use of it. Special words, the Olde Tongue, were linked to the usage usually, but not always. The words just helped you to focus and ‘stay on target.’ These words helped magicians to focus on what they were doing and not get lost in the process. They can't get permanent jobs, people don't want to hire street-rats, and they don't want to get too far on the illegal side, magic is so forbidden that they can't use it for healing and such, the group has about ten members. [Answer] When life's kicked you to the curb, and all you have is your wits and magic, the sky is the limit what you can--and will--do to survive. Options: 1. Start a market stall. If one kid can use fire, cook food. If one can conjure up water, steep tea. If one can stimulate plant growth, grow and sell fruits and veggies (even when no one else should be able to). 2. Entertainment. It's been mentioned before, but that's what a lot of orphans do: entertain the masses to get a coin. Magic shows, singing, dancing, plays, light shows, dancing fruits, whatever gets the largest crowd to stop and look and pay. 3. Work for someone. You have a bunch of eyes, maybe someone will pay for information (business owners that want intel on the competition, contract killers that need consistently accurate information, guards that need someone to keep an eye on a suspicious group). 4. Grow your own food. You have space, start a garden to feed yourselves. 5. Learn a trade. If eating is a big thing, then you'll be motivated to learn something new, or you and everyone left alive that you care about is going to starve one day at a time. Chop chop. 6. Learn to hunt for your own meats. The skins can be sold at the market, and some apothecaries would buy some of the body parts (rabbit's foot, spleens, livers, these might be ingredients to potions and whatnot) 7. Another aspect of your world that has been left vague or unclear. These are orphans that need to survive. If they can do none of the above, they'd study the world around them and see what they can come up with together. Many brains, all attached to a stomach that likes being full. [Answer] ## Black Market Magic If the crown has a royal monopoly on legal magic use, but yet almost anyone could actually use magic if they learned how then there's almost certainly going to be a thriving black market in unlicensed magic services. And this doesn't have to imply immoral or otherwise-illegal activities like murder, theft, etc. If one of the kids can, say, cast a healing spell, they might offer that to people who can't afford royal healers. Other options might involve mending broken objects, divination spells ("Tell your fortune, mister?"), finding things that have been lost, and so on. They quietly offer services to trusted members of their local community, and then receive payment in coin or barter. [Answer] I could see them using their magic for various purposes, but since magic is illegal, they would have to be hidden. If your kingdom has paper money, and magic can be used to spread ink onto paper with high accuracy, forgery is a possibility (and an easy one). If the king is evil or highly placed businessmen/merchants/officers are corrupt, I think your street band could reasonably make a point of only stealing from them, if your aversion to theft is moral related. Magic could also be used to stage "Magic Shows," as a double bluff. People think they are being fooled to think tricks are magic, but are actually witnessing magic. This assumes that magic shows are not forbidden by the king. Another possibility is that they use magic to give themselves temporary disfigurements, to make begging effective enough to survive. Are there any other rival gangs in the area? If so, do they have magic or not? Is their a trade in black market magical items? If so, set to work producing these. There are a multitude of other ways magic can be used to make money, but the key is that they have to be out of sight. If you stick to that you should be able to find something. [Answer] The designer handbag method: Sell something, rugs, sacks, handkerchiefs, whatever; use charm magic to make people pay way over fair market price. The shark tank method: Use magic to add value to merchandise: extra sweet apples, extra sharp knives, extra soft linen, etc [Answer] "How can street kids make enough money to live?" For many real street kids, the answer is prostitution. If you are a streetwalker some magic power could be very helpful. The magic these kids have could be used to remedy or prevent the various hazards that come along with being a prostitute, the specifics of which are here left to the imagination of the reader. In a pinch, the magic might be used defensively to escape a bad situation, but otherwise, magic would mostly be used by the individual on the individual in private so the risk of being caught would be less. Self-spells could also be used to gain market share, by various methods which are here also left to the imagination of the reader. This scenario is probably not going to be taken up by Brandon Mull anytime soon. [Answer] # An everyday guide for the magically gifted street-kid: 1. Conjure up food. 2. Conjure up stuff. 3. Eat the food. 4. Sell the stuff. 5. Repeat. Intelligent street-kids should be able to come up with whatever little measures would make sure that they don't get caught doing magic by the guards. What these might be will depend on how magic is policed in your world, but should typically include things like: * Doing it in a nice, secluded spot. * Alternating between the sellers of the stuff so that a few kids don't become recognized as "those kids who always have some suspiciously good merchandise that they may have needed either magic or theft to acquire." * Giving conjured items a bit of "weathering" so that they don't appear immaculately new. Should not be taken too far, just a smudge of dirt here and there, and perhaps some light scraping in strategic places. * Not conjuring up anything too ridiculously expensive that will get them noticed immediately. [Answer] Use the magic to clean clothes and shine shoes. Use the magic to mend things. Create lights for people on dark nights. Create "umbrellas" on rainy days. All of this is stuff that anyone could do. However, most people may be loathe to use up their mana on such trivial tasks. Paying the kids to do it would be seen as a double public service. 1. You give money to the kids. 2. The kids use up their mana doing trivial things and can't build up enough to get into real mischief. [Answer] This answer is on the edge of what might be legal in your world and depends on the amount of gullible and/or overconfident people (a.k.a. tourists or drunks) in town, but it's worth mentioning. The children could play the [Shell game](https://en.m.wikipedia.org/wiki/Shell_game "Shell game") with said gullible or overconfident people. A few would watch out for trouble, a few would play, a few would do the encouragement etc. Any evidence of having played this game would be easy to get rid of. Cups and shells can easily be discarded and recreated. Playing this game wouldn't even require magic, just sleigh of hand, but the effect could be increased by a very small magic spell. The child operating the cups could use a mantra as the focus words for the spell, something like "pick a cup, any cup". [Answer] Use magic to live longer than everyone else. Accumulate knowledge, and thus power via longevity. Rule the world by modern times by inventing every relevant piece of technology, pretending that magic isn't real erstwhile killing off competitor mages. Magic is for doofuses unless it can make you live longer. A rifle beats a fireball every time and not dying is the only way to beat death. [Answer] They could try to group up and use their magic to get an information advantage over the authorities. If the magic works to gather information and also to do illusion/charming magic to convince any guard who happen to suspect things they didn't see anything. With enough practice they should have gotten an information advantage over any guard service and that's when the real fun begins. They could start feeding guards wrong information so they start watching the wrong people. Probably mostly people deemed smart enough to unfold their plans but also some real madman once in a while (for plausibility). The kids (who are probably grown men at the time) will be free in their magic practice and the ones who could be a threat at exposing them will be the default suspects. [Answer] ## Use magic every day.. Unconsciously Since magic is restricted and using magic is uncommon, it's possible that kids even don't realise what they are doing is magic. No, sir, I don't know about magic. Everybody knows witches are eating kids like me. If I were a wizard I would live in a duke's house So this gang of kids is acting like another street kids, but more effective because they sometimes use magic. There are numerous options: * panhandle. I could see who could give more money. I just ask and get silver shilling and once got gold coin! * pickpocketing. I could see how much money in someone's pocket. I whistle the song and he don't see what I'm doing * gambling. I just wish to win and sometimes I really win. But I'm exausted after that * etc etc. Anything! I just [doing] and I [get it]. You say it's a magic, really? [Answer] 1. Begging. If your medieval city has any religious orders which have vows about giving alms to the poor, the kids can turn to these for a handout. Otherwise, just generally begging on street corners. Be aware that your kids will be in competition with other street kids, with adult beggars and possibly with organized gangs of beggars. If you are not too squeamish or too empathetic, watch the movie Slumdog Millionaire to see a plotline about adults deliberately maiming children to make them more "pitiful" and thus more lucrative as professional beggars. 2. Child Prostitution has been mentioned elsewhere. 3. Picking through cesspits and rubbish heaps. Medieval societies didn't throw away the volume of stuff that we do, so didn't have out massive landfill sites. But there still might be stuff worth scavenging (food scraps) or reselling (cloth rags, bones). Again, bear in mind that they'll be in competition with other street kids and poverty-stricken adults for any spoils. Also, depending on where in the world you are, they might also be fighting wolves, feral dogs or vultures for the food scraps. 4. Sell their urine. Various medieval cloth making processes and leather tanning processes used urine. People used to sell it to the Fuller or Tannery. Probably earn a little cash, but not enough to live on. 5. Do the jobs no-one else wants to do. You say no-one will employ street rats, but there may be some horrendously smelly, unpleasant or dangerous jobs which someone will pay them to do. Collecting wheelbarrow loads of chicken dung to take to the tannery, or emptying full cesspits, for instance. The TV series [The Worst Jobs in History](https://en.wikipedia.org/wiki/The_Worst_Jobs_in_History) might give you some ideas. However, also be aware that there were lots of Guilds and 'closed shops' in the Middle Ages. There might be some appalling jobs in a tannery, but perhaps only apprentices in the Tanners' Guild were permitted to do them. 6. Random odd jobs for dodgy people. Desperate kids can be exploited. Street kids are 'invisible'. Put these together and the kids might earn a copper here and there. Carrying a message to someone. Acting as a lookout for some dubious goings-on. Reporting back on when Mr. Smith comes and goes from his house, or listing every man who Mrs. Jones talks to when she's at the market. [Answer] If magic is a second stamina, perhaps they can use a (banned) olde tongue word to transfer some of their stamina to an interested customer-- for a price. Essentially trading their life force for a bit of coin so they can eat for another day. (This strikes me as something actual street kids do in the real world, allegorically anyway). [Answer] Magic circus with with magic on impact but does nothing on impact. It's just flashy while traveling creating a spectacle of images and/or sounds, attracting a lot of viewers on the streets. ]
[Question] [ Whenever one thinks of something new to introduce to war I always think: Yeah. They were smarter than you and more experienced. They had the ability to think of your basic idea and did not. Probably for a reason. But I'm curious to actually find out. Lets imagine a portable watchtower that can be constructed in the field. Height is about 15 meters. And it has wheels. With the sole purpose of having a soldier on top to surveying the battlefield and report back to people below who in turn would inform the general of what is going on. The setting in question, this can be very general, already uses signals and banners...etc to identify units so a watcher on top should get more information if surveying from a height of 15 meters. Anyway the tech is roughly 16 century. Nothing more. I think you all know the problems of dust clouds or failure to recognize friendlies coming up from a direction and thinking them hostiles...etc Obviously we know from history that even siege towers were made, it took more time but they need to be armored and this does not, and that they were even mobile. So. The ability to make it is not impossible. So. It's a question of is that a good idea not if it could be done. Is this a good idea that adds value to the force in question? Why? Not a good idea? Why not? Edit: As requested to specify the usage of them. I thought it would be a little general. Basically I imagined that the material of making them would be part of the baggage train so that a commander would make one if he thinks it would help. Obviously if he sent a cavalry detachment to ambush the enemy or if the battle is a seaborne landing then again that is not useful. So. It only becomes a tool for the general. Example. The two sides are already engaged in melee. Then the commander, from the back as it is usually done, to make the tower. The tower is quickly erected and manned. Then maybe the watcher sees an week section or can see reinforcements coming to a section of the enemy's line...etc. [Answer] You're vastly over complicating the problem. You can easily have an observation platform that is 15 meters (or more) in height without all the elaborate engineering. All you need is; * a series (2 or 3) 5 meter lengths of solid timber poles that are pre-drilled so they can be bolted together; * 4 to 8 x lengths of stout rope that can be tied off to anchor points on the poles and to spikes in the ground; * add a small viewing platform that can be fixed to the upper pole plus a rope ladder attached to it (Edit: or as someone else suggested pre-installed metal rungs; * a couple of dozen fit soldiers with mallets; and * a set of signal flags, quill, ink, paper and weights for dropping messages. Then you basically just treat the whole exercise like raising a marquee without the canvas. (Alternately think of it as a ship's 'crows nest' transported onto land). You assemble the observation post at the ground of your choosing by simply having a construction crew hoist it up. Then you fix it in position. No wheels, no fancy engineering. And you can carry as many as you want on wagons as part of your baggage train. If lenses have been invented then so much the better - the crew gets telescopes as well! As for how useful it would be? It depends on the tactical situation. It could potentially be very useful in one situation then not at all in another, but at least its simple, quick to set up & inexpensive. [Answer] # Depends This highly depends on how it is constructed - and used. Let's look at two designs: ## Cart-tower A cart-tower is somewhat top-heavy, and while it gives the sight even on the move, it has the downside of being effectively a siege tower that you haul with you. You get seen, it is slow, it threatens to fall over. Nope! Hard pass, unless you are in a siege. ## Cart with fold-up tower Let's lighten the thing. A barrel, a long log, and a hinge that mounts it to a cart. It's light and can also transport other things on the cart! Great! We can't use it on the march, but once we set up camp, we pull up the tower, secure it with a few ropes and we got an outlook! Now, this is handy, but also constrains us to terrain which the cart can move through. # Added Value? ## The army on the march Now, what is the added value? Actually, unless the army already marches with heavy equipment on carts (like cannons), it being bound to a cart can become a downside: you get slowed down to the speed of the cart with the tower. An army without carts marches. All the equipment is distributed on the backs of the army, and surprisingly, armies (or large detachments; the front and rear guard always) marched often this way to be faster and less dependant on terrain as they went and cleared the way of enemies or made sure none came from behind. Then they waited for their slower supply trains or pulled up to the waiting supply train, restocked, and separated again. Pure cavalry armies even could go with almost no supply train, as the Mongols showed. ## Upsides I see such a pop-up tower would accompany siege units, which themselves are slow, and the supply/baggage train, which already comprises of carts. The first group can now better gauge the battlefield and where the shots land with it without much loss of speed. The latter group allows to possibly safeguard the position by seeing better or to relay commands to a unit that is detached from this position. ## drawbacks However, the fact that it is heavy - even as a pop-up design - and thus reduces other resources that can be transported is a downside that has to be looked at, but it is not crippling so. As a result, it would be not universal to carry one but could be an addition in some units or under the command of some generals. Also, as it needs to be transported by cart it is bound to fortified roads or open terrain like other carts, so it might be dropped off if the terrain goes unfavorably. A 15-meter tower is really easy to spot. So erecting it in enemy land acts as a huge target for the tower, making it a bad thing to put up in some circumstances. The terrain might make the tower obsolete in alpine regions. For example, fighting in the Alps, you could often send a spotter some hundred or such meters away up a mountain slope and get a similar height advancement while retaining cover for him. His signals wouldn't be as visible though. [Answer] I think it would be a lot more useful as a simple tripod tower with a climbing rope. All you would have to do is lash three poles together and tie a rope to the top with knots for the watcher to climb up. Wheels would actually slow the tower down due to added weight and terrain. If you're already on a hill, even a short tower could be useful to observe enemy movements. Mind you, a common tactic was to send out skirmishers to block the view of one's main force with just their bodies and horses alone, so the ability to see over them would be a pretty decent advantage. Also consider that field fortifications were already a thing. Roman engineers for instance were known to be able to set up a field-expedient fort while simultaneously fending off an attack. They also brought many of the materials with them. From Wikipedia: > > The most detailed description that survives about Roman military camps is De Munitionibus Castrorum, a manuscript of 11 pages that dates most probably from the late 1st to early 2nd century AD. > > > Regulations required a major unit in the field to retire to a properly constructed camp every day. "… as soon as they have marched into an enemy's land, they do not begin to fight until they have walled their camp about; nor is the fence they raise rashly made, or uneven; nor do they all abide ill it, nor do those that are in it take their places at random; but if it happens that the ground is uneven, it is first levelled: their camp is also four-square by measure, and carpenters are ready, in great numbers, with their tools, to erect their buildings for them." To this end a marching column ported the equipment needed to build and stock the camp in a baggage train of wagons and on the backs of the soldiers. > > > Camps were the responsibility of engineering units to which specialists of many types belonged, officered by architecti, "chief engineers", who requisitioned manual labor from the soldiers at large as required. They could throw up a camp under enemy attack in as little as a few hours. Judging from the names, they probably used a repertory of camp plans, selecting the one appropriate to the length of time a legion would spend in it: tertia castra, quarta castra, etc. (a camp of three days, four days, etc.). > <https://en.m.wikipedia.org/wiki/Castra> > > > Compared to all that, I think lugging around a few poles and some rope would be insignificant. You mentioned 16th century technology, so you would probably be in the age of gunpowder. Field fortifications and the like were really popular in western Europe in that time period. That was the era when star fortresses were popping up everywhere, an era of trench warfare when soldiers often did more digging than fighting. Building and digging was absolutely necessary on both offence and defense, so a lookout tower would probably not be out of place. Edit: Watchtowers similar to this were also used in the Crimean War: <https://www.jstor.org/stable/20538506?seq=2#metadata_info_tab_contents> [Answer] Much simpler alternatives were likely in wide use. A big tower with wooden wheels would be difficult to move even on modern paved roads, so you can forget about such a contraption keeping up with a marching army in pre-industrial times, on rough roads or in the mud. Armies mostly marched on foot, with supplies carried on horses or mules, (or horse carts following the army, significantly more slowly). Carrying around such a contraption would be a logistical nightmare. What to use instead? Two siege ladders bound together in the shape of an "A". Quick to set up, quick to dismantle, and the reason a medieval army starts a military campaign is to besiege some castle or town, so they'll need siege ladders anyway. [Answer] Considering the time period, this tower would be made of wood. ![wooden watchtower](https://i.stack.imgur.com/a5Js9.jpg) Something like this. The logs involved in this design are around 4-5 meters long and average 20cm in diameter. Seems about right. There are about 72 logs in the tower, totaling ~ 325 meters. That's 10 cubic meters of wood - about five tons ([1](https://www.britannica.com/technology/Conestoga-wagon)), plus the wheels. The wheels are a tricky bit. How do you design the suspension for such a massive object, using medieval materials? The Conestoga people figured it out - we can too. It likely weighs about as much as a fully loaded covered wagon ([2](https://www.inchcalculator.com/lumber-weight-calculator/)). So let's assume it can be built and works reliably. 6 tons will require a substantial team of horses (6-14) to pull it steadily ([3](https://animalhow.com/horse-pull-capacity/#:%7E:text=A%20healthy%20horse%20will%20typically%20be%20able%20to,we%20have%20some%20amazing%20number%20to%20look%20at.), [4](https://horserookie.com/how-much-do-horses-weigh/#:%7E:text=An%20average%20horse%20weighs%20900-2%2C000%20pounds%2C%20depending%20on,Clydesdale%20%28think%20Budweiser%29%20weighs%20in%20at%201%2C800-2%2C000%20pounds.)). It will also need a wide, flat road, or risk tipping, breaking, or getting stuck. From the top, you can see an extra 8 kilometers ([5](http://www.ringbell.co.uk/info/hdist.htm)) vs. a guy on a horse - enough to make you a lot harder to sneak up on (depending on the terrain, of course). In an area with lots of rolling hills, low scrub, and highway bandits, I could see it being very useful to have a way of looking (and potentially shooting) over those obstacles. It might be quite useful in guarding valuable wagon trains through unsafe (but well-paved!) territory. I wouldn't try to take this thing over much of an incline. In a pitched battle? I think it could be useful. I'd say send the general himself up there with a set of flags - one pair for each regiment, say. He picks up the set that belongs to the regiment he wants to signal and uses some flag language to communicate commands. Each regiment includes a flag officer or two whose job is to watch the flags, communicate with the troops, and relay information to the general using flags of his own. I believe that the general with a better view of the action and faster communication between the various parts of his army would have an advantage over an adversary relying on horse messengers. He could react faster and more intelligently, avoid traps, and spring them on his enemy before they could respond. The other option is always to leave the tower behind, give all those horses to your scouts, and have them ride ahead and to all sides looking for danger and reporting back. Advantages: the scouts can potentially range farther, and unlike the tower, they can see without being seen. They are also much more nimble, not requiring the medieval equivalent of an interstate highway to move along. In situations requiring fast travel, rough terrain, or stealth, I think scouts would be preferred. But overall, I think the mobile watchtower is a pretty good idea. Sources: [Conestoga wagons](https://www.britannica.com/technology/Conestoga-wagon) [lumber weight chart](https://www.inchcalculator.com/lumber-weight-calculator/) [horse pull capacity](https://animalhow.com/horse-pull-capacity/#:%7E:text=A%20healthy%20horse%20will%20typically%20be%20able%20to,we%20have%20some%20amazing%20number%20to%20look%20at.) [horse weight](https://horserookie.com/how-much-do-horses-weigh/#:%7E:text=An%20average%20horse%20weighs%20900-2%2C000%20pounds%2C%20depending%20on,Clydesdale%20%28think%20Budweiser%29%20weighs%20in%20at%201%2C800-2%2C000%20pounds.) [horizon calculator](http://www.ringbell.co.uk/info/hdist.htm) [Answer] ## Frame challenge Are you fighting in a completely flat area without hills and trees? Normally battles were fought in hilly areas or even in valleys, so that the generals and other soldiers could get a clear view of the battle and direct companies to where they would be most effective. Battles could sometimes be determined by the first army to get to an area and choose the high ground, so they could see better. Fast forward to more modern times and the artillery was often set up on these hills to get more range as well as being able to see well. Even before artillery, archers would be posted higher up to also get better range and visibility. > > It's barely hyperbole to say that the landscape itself was the highest-ranking general organizing the fight on those three bloody days. So, it's not surprising that geographical features such as Little Round Top, Seminary Ridge, Devil's Den, Culp's Hill and others are more widely known than the names of the victorious generals. Only iconic Confederate Gen. Robert E. Lee and his subordinate Gen. George Pickett, whose ill-fated charge across open fields was the crescendo of defeat, are as well remembered. > > ... > > Military commanders have appreciated the importance of landscape for millenniums, and nowhere is that better expressed than at Gettysburg. Remembering that pivotal battle, we would do well to consider how topography and it's underlying geology affects our daily existence, determining the course of roads, the locations of homes and factories, the placement of our cities and our ability to grow food. Lessons from Gettysburg extend far beyond heroism, history and culture-war subjects to the way in which we live our daily lives. More than we commonly realize, topography is destiny. > > > <https://www.courant.com/opinion/hc-op-place-leff-gettysburg-high-ground-shaped-des-20130620-story.html> Rewind tech and society from your setting a little and "generals"/commanders/war chiefs were on the front lines, leading the soldiers in 100% melee battles. They didn't direct anything, they assumed people knew what to do. Sometimes this was a set out plan prior to the battle and sometimes it was signals from the front. > > ... Alexander the Great’s psychopathic urge to get down and dirty once he’d instilled his commander’s intent among his generals often ran the risk of his being unable to revise tactics in the event of something not working as planned, and nearly cost him his life on more than one occasion. Hannibal, once he’d similarly briefed his trusted lieutenants, usually joined his Celtic contingent in order to ensure discipline in its ranks, dressed in a common soldier’s armor so as not to be marked by the Romans, but recognizable enough to his own Celts. Gaius Julius Caesar preferred to run his battles from the rear but was quick to draw his sword and lead from the front in moments of crisis. ... > > > <https://www.historynet.com/did-generals-really-lead-from-the-front.htm> If someone needed to get even higher to see something, they climbed a tree. This is also likely part of the reason why war animals, like horses, were used, to get a better view of the battlefield over the heads of soldiers. I can't find any proof of this, but the military isn't stupid. Or at least good ones aren't. They would find and take any advantage they could. ]
[Question] [ Let's say there are 2-3 people in a carriage (or van,boat, or anything with a similar size), constantly on the move, unable to hunt (because of reasons) and of course unable to stay in one place and have a farm. What food would be better for them to get the most nutrition they could carry (and grow the food for it, if the food they use isn't grass that's on the road) and how many calories really can they expect, without having to consider literally tons in "luggage"? I though perhaps land snails, or quails, but neither seems really feasible. Thanks in advance. [Answer] HERDS: * The obvious choice is to herd animals. This wouldn't work in the boat scenario, but even people who can't hunt can still bring goats along with them. Goats (or insert herd animal here) walk on their own with a little prodding, and produce milk directly and can be slaughtered for meat. Most wagons travel over rough enough terrain that they don't outpace a traveling herd. Yaks can be your transport animals, live off grass, produce milk, and can be slaughtered (but are limited in climate). * In your boat scenario, fishing and netting isn't exactly hunting, but may violate the preconditions. Tossing a net in the water and dragging it behind to catch fish is fairly passive, and can produce quite a bit of food. Based on all this great feedback, I'm adding that trained animals could be used to drive fish into nets to increase the harvest. The big take could be shared out with the animals as their cut - either as domesticated animals or as a symbiosis between species. * In both of these scenarios, it isn't a perfect diet, but it can produce extra that can be sold/traded for whatever else you need. Herding is a sustainable lifestyle all on it's own. [Answer] If they are unable to farm and hunt then they are left with trading for food: they can pay with money or barter some of their goods with food provided from the locals they meet during their wanderings. It doesn't really matter what food it is, and it depends on the place they are at the moment. It can be cereals or legumes if they are crossing a farming area, it can be dried meat or fish if they find themselves in a more hunting/fishing region. They won't be carrying with them more than a few days of stocks, and they can get info from the locals on the routes to prefer/avoid. [Answer] ## Foraging It have been done by whole armies during ages. You don't have enough food for your army? well, just take what you need on local area. Wild animals runs, crops don't. It can be devastating when a whole army does it, but if it's only 2-3 people, it can go more or less unnoticed. It can make you get troubles with local folk if you get caught though, but, well, you are nomad so reputation is not a big issue. [Answer] Pemmican. <http://scoresurvival.com/pemmican-native-american-super-survival-food/> This is dried, preserved half fat, half meat with some dry fruit. It will keep a long time if dry. The linked article quotes 300 kcal / 62 grams which compares favorably to butter (my favorite high calorie density food) at 350 kcal / 50 grams and you wont get scurvy eating only pemmican. So if I eat 2100 kcal a day of pemmican (it is hard work, riding in the van!) that is about 500 gram or 1.1 lbs. Having 6 25kg bags of this stuff in the back of the van is not outrageous and that, and the love, and the beer will sustain me and my driver for half a year. You could make this much pemmican with a couple of buffalo. Or if I were a farmer and I were on a nomad route I would make a bunch of pemmican when I slaughtered some animals and then sell it to the nomads when they showed up. [Answer] For a single family constantly on the move, you want nonperishable and energy-dense food. If they get to keep a herd, it is the best option since a living animal is as nonperishable as it gets. Otherwise, you want energy-dense low-moisture foods for your family. This means mainly fatty foods. Your second best option is to render fatty meats to get rid of the moisture which would leave you with a good staple that can last for weeks to months if kept cool. Steppe nomads were known for storing meat like this as their winter staple. Nuts are also a good option in the same niche although likely to be less abundant - high fat, good source of protein and micronutrients, low moisture especially if roasted and salted. Same goes for legumes if you can somehow forage for them. As an alternative, you can carry around some flour to and trade for it time to time. At worst you can easily make hardtack with it or mix it with water for some porridge, make flatbread etc. It is nutrient, can be stored long enough and carbs are good to stay energetic if your nomads are active. It has been the human staple for millenia for a reason. For lean meats that do not come with enough fat to fully cover it once rendered and cooled, which is the majority of what you will have if you do not have herd animals since small mammals, fish and poultry all fall under this, salt is your option. Salted and dried meat is also durable and a good staple. Dairy products are also something your nomads can look into. Hard cheese is perfect but can end up possible to acquire only through trade, since takes quite a bit of effort to make. Same for butter you can render etc. You can make yogurt which can make any milk you find last for a few days longer than the hours it normally would without refrigeration. All you need is some tall flower or grass off the fields you know to be harmless for the bacteria on it. Following these is dried fruit. You can easily forage or trade for it since it is abundant especially in the form of berries. Perfect for instant energy, calorie and micronutrient dense, although lacks in proteins and not really suitable to be a staple. Also if you are not an experienced forager some berries can be nasty. Alcohol is the final thing to look into here. It can be a good byproduct from fruit juice you would get if you are drying fruit as pulp or even milk. If you are making it, you can trade it. If not, trading for some liquor time to time might be a good investment to keep the spirits high, not to mention some niche uses like as a disinfectant. [Answer] ### Potatoes Potatoes might be a good food for your nomads: they are nutrient-dense and contain lots of starch, they don’t need a lot of space to produce a lot of energy, they are easily sustainable, and they could be planted in a carriage. That last point may seem odd, but home growers sometimes plant potato tubers in tall, tied off bags of soil to keep from having to do a lot of digging at harvest. Your nomads could hang bags of potatoes off the back of the wagon once they have enough leaves to photosynthesize, and start the plants from saved seed eyes in planter boxes inside the vehicle. Health-wise, potatoes are starchy, so they are filling and good for keeping you going. You can only expect to get about 110 Calories from a single medium potato and it doesn’t fulfill all your dietary needs, so it would need to be supplemented by something else, but foraging or another answer would do that for your nomads. On the other hand, you do have to cook them and make sure they don’t go green while you store them. That could be done by leaving them in the soil until you need to eat them. Another downside is that potatoes need soil that is rich in nutrients. But, if you have animals anywhere near the nomads, you have the beginnings of good fertilizer. All in all, potatoes would be an excellent choice for the nomads to consider. Sources: * [11 most nutrient dense foods on the planet, healthline.com](https://www.healthline.com/nutrition/11-most-nutrient-dense-foods-on-the-planet) * [Wikipedia on potatoes](https://en.m.wikipedia.org/wiki/Potato) * [Livescience.com on potato nutrition facts](https://www.livescience.com/45838-potato-nutrition.html) [Answer] milk or dairy product mostly like butter, yogurt, cheese, milk candy/milk cake, and milk wine (ayrag or kumis and kefir, they are considered as alcohol upon googling it) outside of meat from domestic animal (since you eliminate hunting) such as horse,cow or yak,goat,sheep they can move as a pack with your nomad, depend on the climate or weather you can make dried or jerky meat, you can also drink the blood or make blood sausage. for boat, fish, squid or octopus, or shrimp if you catch it during night, though base of my knowledge its far faster using harpoon or spear to catch fish rather than fishing rod (assuming the water is clear enough), assuming this is small boat unable to carry big catch using net, or go landing or sail near the shore to take nearby plant such as fruit or coconut for hydration and food, or finding clam near the shore. if they cant even have the chance to land or come near shore they need to eat their fish, squid, octopus, shrimp RAW since you cant cook in the boat, unless this is modern boat which i has no knowledge about, but im more worried about water since you will depend on rain for that and you need to boil it to make sure you dont get sick. as far as i know, two or three medium size fish is enough for a single person to keep going. [Answer] Nomadic societies sustained themselves on mobile animals for millennia. Not for meat alone. Milk (and cheese, butter, yogurt), fur for warmth and meat upon euthanizing older ones. Fish, dried and salted lasted for months. [Answer] In situations where you are on the go for long periods of time you need food that will keep most importantly. A good option for nutrition would be reduced soup as it can be eaten a bit like jerky and can be prepared as a way to keep stews made on the go when resources are available. keep in mind however they will still need water, both to make soup and to drink. now storing water on long voyages is tricky because it can become contaminated easy and so a viable option is to of course make grog, in other words bleach the water with enough alcohol that bacteria cant survive in it, and contrary to popular belief it doesn't have to be potent enough that they are drunk all the time. You can also just boil and recollect water to sterilize or keep in a hot metal container for long enough. some other good foods include: hard tack basically flour + water problem is it is low in nutrition and can become prone to weevils but will keep longer than traditional bread salted meats/jerky hard to make especially on the go with limited resources but basically the same as reduced soup in nutrition and keep-ability dried fruits and herbs this is less often used as a whole meal but some stuff to keep in mind especially because more can be gathered on the go and don't forget you can always have a combination of the various foods for endeavoring! [Answer] Piracy, pillage and plunder They attack homesteads and small villages when it's dark, then grab what they can and gallop off into the night. Also of course they can steal non-violently and surreptitiously. ]
[Question] [ Imagine a planet orbiting a star some billions of lightyears away from us, the planet is 4 times the mass of Earth and is covered with ice 100km thick on average. It is believed that liquid ocean exist beneath that thick ice sheet and it could harbour life, any way I like to know how quakes can occur naturally on the ice without scarring the surface or through divine intervention? [Answer] There is a gravitational pull from the star on the planet. This causes movement in your underground water just like the tides here on Earth. You will still have the 'bulges' in your water table. These exert a pressure on the ice that's above it. Since it is your world, you can decide how strong these forces are going to be: the quakes can be mild, or they can bring down your ice mountains. Note that these processes are actually happening right now on the icy moons in the solar system, like [Europa](https://en.wikipedia.org/wiki/Europa_(moon)): > > The predominant model suggests that heat from tidal flexing causes the ocean to remain liquid and drives ice movement similar to plate tectonics, absorbing chemicals from the surface into the ocean below. > > > From a 2014 NASA publication: [Scientists Find Evidence of ‘Diving’ Tectonic Plates on Jupiter’s Moon Europa](https://www.nasa.gov/press/2014/september/scientists-find-evidence-of-diving-tectonic-plates-on-jupiter-s-moon-europa/) . Note that Europas ice shell is only 20-30 kilometer, but again, it's your world ;-) [Answer] Ice worms. [![ice worm](https://i.stack.imgur.com/RS6zB.jpg)](https://i.stack.imgur.com/RS6zB.jpg) [source](https://www.youtube.com/watch?v=lRUdbdkgXU0) These things are big. The really big ones rarely move, their energy mostly coming from varying tidal forces on their bodies. Very occasionally they do. When they do, stuff shakes topside over a large area. These big ice worms leave tunnels that gradually fill back in. The presence of these tunnels can be helpful for a fiction or game. Big ice worms start as smaller ice worms. Your guide can tell worm size by the shaking. The big ones are deep, and nothing to worry about. The little ones sometimes shake even more than the big ones, and those you do need to worry about. They are shaking things more because they are right underneath you, and possibly interested in you. [Answer] Phase Changes Within the Sheet Itself So, ice isn't a singular material and can exist in any of 11 unique forms each with different pressure and temperature requirements. On a planet with a 100km thick blanket of ice, the ice in the middle and bottom layers would very likely be subjected to many extremes of pressure. [![The Many Phases of Ice](https://i.stack.imgur.com/g3BXn.png)](https://i.stack.imgur.com/g3BXn.png) Your "ice quakes" could be ice reacting to changes in form (almost all of which include a molecular realignment in the crystal structure) due to pressure changes within the ice sheet. These would cascade out quickly from the "epicenter" as the pressure gradient forces nearby ice to crack and realign itself in response to changes in pressure or even creating thin layers of melt between the sheets where the ice can "slip past" itself. The top layer of ice need not even be very involved here, as changes in the lower and middle layers of the ice sheet would send shock waves which would travel quickly through the thick solid "cap" on your planet and the thin "melt layers" could let much of the surface move independently from the ice under it. Combined with some of the other answers such as tidal forces or geothermal activity, this could easily explain anything you need about the geology of the planet. In addition, while most ice has a lower density than water and floats on top of it, many of the more exotic forms which might be formed in your ice sheet could easily be more dense than the water, working themselves down through the ice sheet over many years until they "rain down" through the liquid layer onto the rocky floor below, only to eventually reheat via geothermal radiation and melt, eventually finding their way back into the ice sheet. [Answer] # Plate Tectonics Under the ice there is water (maybe) and under the water, there is rock, then under the rock there is a molten core, this allows for tectonic plates to move and shift like it does here. The same things that cause earthquakes on earth will cause earthquakes on your planet. The water under the plates has a dampening effect on the ice, so the ice shakes, but doesn't break or shift. [Answer] Air pockets underneath the ice? They are compressible, and allow the water below to move and splash around to form waves. Add in tidal and Coriolis effects, and you get regular localised icequakes as the water moves the air around ]
[Question] [ (Hoping this isn't another too-broad question...) I just want a different way for my aliens to breathe that isn't obvious to a human's eyes; it makes them seem like they don't breathe at all, and their chests don't rise and fall with every inhale-exhale. [Answer] Double set of lungs: imagine a creature much like a mammal. now you put a second chest in front of the fist one. Attach the muscles to the barrier between the front and the back lungs. When the front lungs are expanded, the rear lungs are compressed, and vice versa. This way, the breathing apparatus is much like ours but doubled, but the motion happens internally. I'm not sure, but i think breathing might be more efficient too, because of the compression. Any variation on that theme (a lateral barrier between mammal-like lungs for example) might work, too. [Answer] # Shell-like torsos and cloacal respiration. If what you want is simply for the animals not to appear like they're breathing, you're in luck: the method you want already exists, and it mostly involves having rigid torsos. Birds are nice examples, but not quite. While the lack a diaphragm like mammals do, their chests also move while they breathe, as muscles in their torso move the vertebrae and sternum up and down in order for it to expand in volume. But there's one kind of animal that, despite not having a rigid exoskeleton doesn't quite enjoy the benefits of a more flexible torso: turtles. Turtle shells, far from some exclusively external armor like you'd see in something like an armadillo, are composed of their ribs and vertebrae. Today we believe this came as an adaptation for digging, but regardless, the final outcome is a creature with a completely rigid torso that can't really expand to let in air. So, how do they do it? Pretty simple, they transferred the job from muscle and bone to just muscle. Turtles have sheets of muscle specialized to contract and relax in order to force air in and out of the lungs inside their shells, allowing for the lungs to expand and contract inside fully rigid, unmoving torsos. There's also another page from the turtle book that you can use in order to make your aliens seem like they don't breathe: butt breathing. That's right, some turtles, especially some semiaquatic and aquatic species can exchange Gases through their butts,something known as cloacal respiration. To explain it: breathing in the water,putting it simply, mostly takes 3 things: the water containing oxygen, a place full of blood vessels to get in contact with the water and get that oxygen through diffusion and a way to make that contact happen. Fish do this through their gills, but some turtles, already having a cloaca packed with blood vessels, adapted to use said cloacas to extract oxygen from the water, especially while hibernating underwater in the winter. This greatly helps turtles with a more aquatic lifestyle spend longer periods underwater, with some species being able to get all of the oxygen they need depending on how active they are at the moment. So overall, if you want a species that doesn't look like they breathe, make them more turtle-like. A species with a rigid, armored torso housing their lungs, as well as muscle sheets responsible for handling their breathing. Couple that with the ability to extract oxygen from the water via something that isn't as obvious as gills and you could easily sell the idea of an alien species that simply does not breathe, or that does so through some overcomplicated, highly alien method, when you're actually just dealing with space turtles. [Answer] Scrotum frog style! [![scrotum frog](https://i.stack.imgur.com/LaSDO.jpg)](https://i.stack.imgur.com/LaSDO.jpg) <https://featuredcreature.com/alright-heres-the-aquatic-scrotum-frog-a-name-and-a-face-you-wont-soon-forget/> T.culeus breathes through its skin. <https://en.wikipedia.org/wiki/Telmatobius_culeus> > > The Titicaca water frog spends its entire life in oxygen-rich water > that typically is 10–17 °C (50–60 °F). It mainly stays near the bottom > and it does not surface to breathe if the water is well-oxygenated. It > regularly performs "push-ups" to allow water to pass by its large skin > folds, which absorb oxygen. It occurs even in deeper parts of Lake > Titicaca, although the limit is unknown. > > > Your creatures also have redundant raisin like folds of skin, possibly all over like the scrotum frog, or possibly on a large pendulous respiratory organ. Instead of pushups, your aliens slowly dance, as though at all times they were doing tai-chi. In circumstances where more oxygen is needed the movements become more vigorous. [Answer] # Unidirectional flow: [Bird lungs](http://people.eku.edu/ritchisong/birdrespiration.html) are unidirectional, so they don't breathe "in" and "out" quite like mammals. Their lungs don't need to constantly change size as much and they have higher oxygenation levels (yes, this is oversimplified). It does result in higher levels of inhaled particulates with less ability to cough things out (so birds have more respiratory infections). Your species could use unidirectional flow respiration more like a pump or [Chinese box bellows](https://quatr.us/history/bellows-invented-bellows.htm) than a western-style bellows like our lungs. Air is constantly being drawn in at one spot and constantly expelled at another. With no net expansion of the lungs, there is no obvious motion. If the inhalation and exhalation locations are in less noticeable spots, then there would be almost no apparent breathing. [Answer] In Larry Niven's "Known Space" series there is a species of plant called "stage trees." They consist of a leafy cluster on top of a straight stem about 2 meters long and 20 cm thick. The interior of the stem is essentially pure solid rocket fuel. There are several cool stories about the origin of these plants, their growth patterns, etc. But the point is, they produce substantial quantities of chemical that includes both fuel and oxidant. Harvest the logs, dry them, strip off the bark, bundle them into a vehicle, and you've got something that will launch to space. Imagine your folk have evolved to eat these. Floating about in their blood is a mixture of both the fuel and the oxidizer. And it comes in their food in exactly the right ratio to be 100 percent used up on reaction. No breathing required. So the waste product is essentially water and CO2. Your folk would emit CO2 and water. They could emit the CO2 as gas through various small pores all over their bodies. And the water could be emitted as sweat or similarly to how we get rid of urine. They would need some nifty chemicals in their blood so they were not explosively flamable. "Keep away from open flames." And their kitchens would be interesting. And No Smoking Please on their farms. [Answer] Perhaps they have somehow evolved a means to process and store oxygen so that it behaves more like ATP. So instead of breathing continuously they could have breathing "meals" where they intake a large amount of oxygen and store it for later use. I'm not sure how much oxygen you could store in something like perfluorocarbon, but it exists as an option for [liquid breathing](https://en.wikipedia.org/wiki/Liquid_breathing). Though I'm sure if pressed, evolution could come up with a better storage system. That said, oxygen is not the only oxidizer, there are a lot of other alternatives for metabolic systems. Lithium ion batteries store a huge amount of energy without any oxygen required. It's not unfathomable that on a different planet the first life forms don't emit oxygen and therefore the [Great Oxidation Event](https://en.wikipedia.org/wiki/Great_Oxidation_Event) never occurs which in turn forces life to improvise an energy storage mechanism where oxygen isn't ubiquitously present. It would be less efficient to have to carry your oxidizer with you because it's usually heavier than the fuel, but if there's none of it conveniently in the air then that's what you'd have to do. For bonus story points that kind of life would have to deal with actual spontaneous combustion, as well as the occasional spontaneous detonation. [Answer] Hyper-porous lung dermis Your species could have millions of tiny lungs all over their body, situated in their skin, each micro-lung having its own micro-diaphragm in the form of muscles similar to the ones that make your hair rise, the arrector pili muscles. Imagine each and every pore on your body being able to imperceptibly take in air and exchange it with the blood throwing through your sub-dermal veins, in a vein similar to active osmosis if I had to put a term to it. Of course, just like with goosebumps you may be able to see what's going on if you look close enough, but from an arm's length or more(conversational distance) it's not going to be that obvious. [Answer] Air-Gills Your aliens passively absorb oxygen from the air by using large gills. To make sure enough air passes over the gills, they need to be in constant motion (either by the whole alien moving or by the gills being moved through the air). [Answer] # Why Breathe? The answer about Stage Trees is good, but there are other possibilities. Maybe they use an energy process not based on slowed-down combustion, and thus do not need a constant gas source as a combustion source. Maybe they are plants, with their light exposure well balanced to their energy needs. Maybe they are robots with rechargeable batteries. Maybe their energy process is faster, but with a storage mechanism, so they breathe a lot while eating, but never need to after that. ]
[Question] [ In my story, a portal links the modern world to a medieval fantasy world. This is sort of similar to Gate: Thus the JSDF Fought There. The North Korean military decides to go through their portal and acquire more land and resources for Kim Jong-Un. The first polity The Korean People's Army encounters is the Orc Federation. The Orc Federation is a massive group of pastoralists and villagers who often raid and demand tribute from nearby communities. The Orc Federation is heavily inspired by the Timurid Empire. The geography and size of their empire is equal to Earth's Central Asia. The orcs only have access to 15th Century technology which is obviously no match for the weapons the North Koreans have at their disposal. The orcs also completely lack any magic. However, the orcs do possess some advantages over not just the North Koreans but humans in general. The first advantage is that they are defending and are really motivated and know the layout of their land better but that goes without saying and that advantage is present in most wars. What makes orcs special is they reproduce fast. An orc woman has a gestation period of only 6 months and generally gives births to twins. Orcs also go through puberty around age 7 and have a life expectancy of 50 years. As a result, the orcs have a large and young population compared to similar empires, 500 million people to be exact which is much larger than North Korea's population or any modern country for that matter excluding China and India. The orcs second major advantage is their physical attributes. The Orcs weigh 200 kilograms on average and are around 2.5 meters tall. Despite their size, the Orcs have the speed of a cheetah, the strength of a gorilla, and the durability of an African elephant. As a result, an orc in close quarters can lay waste to many human opponents with ease. The final advantage of orcs is their sexual dimorphism. Orc women are just as big and strong as the men so they can participate in combat just as well. This potentially doubles the size of the orcish forces before they run into logistical and demographic problems. Even a herd of fast elephants won't last long in a battle against modern artillery and naval ships and tanks and aircraft. That is why after the first few major losses, the orcs stop fighting fair and no longer attempt or participate in set-piece battles. The orcish military takes off their uniforms and starts fading into the shadows and dressing like civilians. The orcs might not be able to do much to the tank or fighter jet in a fight but they can still kill even modern infantry with ease. Whenever soldiers go on patrol, especially at night, the orcs ambush the ones who stray too far from the base; generally killing them before they even realize what's going on. The orcs start sneaking behind enemy lines and start raiding lightly-defended outposts and attacking enemy supply lines. The orcs start launching insurrections against the North Koreans who are guarding occupied towns and villages. The orcs start sneaking onto ships at night and begin killing the crew. The speed of the orcs combined with their toughness means assault rifles aren't very effective against them. If the orcs can get to the humans before they can deploy heavier weaponry or call for backup, they could perform a lot of successful attacks. Soon, it is becoming less and less safe for squads or even platoons of infantry to venture into orc territory. The soldiers are mostly safe in their bases and vehicles but they have to leave their forts and vehicles at some point. Occupying the Orc Federation would get more and more expensive, especially when the military has to be far more mechanized against a foe than you would expect against a foe with mostly medieval technology. Later on, NATO starts arming the orcs with rocket launchers to take out North Korean vehicles. So the question is could medieval, non-magic superhumans win an unconventional conflict against a modern military like North Korea? A lot of the advantages of the modern military industrial complex are nullified in guerilla warfare, which is why guerillas have waged war against the USA and Soviet Union for so long. [Answer] No First, though someone more practiced in history may prove me wrong, to the best of my knowledge, it's insanely rare for a guerilla effort to achieve "success" and when it has happened there's always something causing the advantage, like the invaders can't keep their supply lines secure. You don't define what "success" is, which makes it difficult to answer the question. So I'll make an assumption: Assumption: Success is defined as killing or removing (by forcing them back through the portal) all humans in the medieval fantasy world and taking control of the portal on the medieval fantasy world side to a sufficient degree that no human can come through it. I sincerely believe that's impossible. Humanity can trivially send a ferocious amount of ordinance through the gate. They can send bullets, bombs... big bombs... Heck, if Kim really got a bee in his bonnet he could send nuclear ordinance through the portal with the only loss on his side being something in the direct path of the gate. On the other side, all the orcs within feet to miles to many miles are dead — and that's ignoring the value of missiles. He can send poison gas. He can send drones. He can send all kinds of things that make it very difficult for me to believe that the Orcs can achieve the assumption of success. Therefore, I must say "no." Assumption: Humans want the other side so badly that they won't use nukes. OK, poison gas. Assumption: North Korea is somehow convinced to not use poison gas. I have a *really, really hard time believing that,* but let's assume it's true. Could the Orcs successfully take possession of their side of the gate? Against an encampment surrounded by hundreds of armored vehicles with a functionally infinite supply of resources coming through the portal? Yeah. No. Assumption: "Success" is defined as humanity can't get a permanent foothold without constant war. OK, this I can believe. Given the conditions you've specified there are enough orcs to basically throw at the invaders forever. The humans would make occasional inroads into Orc territory, but it would be a constant battle and they'd be regularly pushed back to a minimum perimeter that the Orcs can't penetrate regardless of numbers and strength. What's left is a stalemate. Except for the poison gas and the nukes. That's your real sticking point. People here on Earth may pitch fits about poison gas and nukes in a way that keeps countries like North Korea from actually using them — but that's simply not true on the other side of a portal — unless North Korea is foolish enough to let someone from Amnesty International through the portal with a guaranteed line of communication. Assumption: What if the portal is only big enough to let, say, two people through at a time? So far I've been assuming that the portal is large enough to allow vehicles through. Let's make it so small that only personnel and something akin to a powered wheelbarrow can get through. What then? Can the Orcs succeed? Yes, if they figure out what's going on fast enough. An awful lot of ordinance can be brought through a portal that's two people wide and all kinds of equipment can be brought through on long carriages. In fact, I can immediately see the advantage of laying a narrow gauge rail through the portal to move quite literally tons of equipment through, ready to assemble. If the Orcs wait too long or don't find out what's happening fast enough, we're basically back to the stalemate. And all of this makes some WHOMPING assumptions: * North Korea wouldn't strike a civilian population. While people deplore striking civilian populations, all war on the planet since WWII has accepted the reality that civilian population centers are open game. Militaries don't exist in a vacuum. Want to damage the logistics needed to fight a war? Take out the civilian population centers. Therefore, I not only believe North Korea (or any other human invader) would attack the population centers, I believe they'd quickly bring drone and/or satellite tech through the portal to give them enhanced light/infravision so they can quickly spot groups of Orcs both large and small. * Human ingenuity, for some unexplained reason, stops. Humans are remarkably clever when it comes to causing harm. How did the U.S. combat guerilla warfare in Vietnam? With [Napalm](https://en.wikipedia.org/wiki/Napalm). It's really stretching the imagination that humans wouldn't figure out ways to use all that advanced tech and chemistry to rain death upon the medieval Orcs. But, is there really no way? Having said all that, and sincerely believing the answer is "no," I'd like to point out one possibility. The [Iran-Iraq War](https://en.wikipedia.org/wiki/Iran%E2%80%93Iraq_War). Ignore the reasons for the war. What we have was Iraq's semi-modern technology including poison gas vs. Iran's human waves. It's a close to the kind of conflict you're thinking about as I believe humanity has ever come. You should study it. It will give you enormous insight into the many variables involved in a conflict like that you're considering including economic and morale costs. The result was a brokered stalemate. But you don't have the rest of the world caring about what's going on. But, had Iraq and Iran been left to that war's terrible end, I suspect Iraq would have won. But there's an argument to be made.... Edit: @DanilaSmirnov points out a great example to further your study of how mismatched sides can fight. The [Anglo-Zulu War](https://en.wikipedia.org/wiki/Anglo-Zulu_War). Neither of the two conflicts (Iraq/Iran & Anglo/Zulu) are perfect examples. The Iraq/Iran conflict demonstrates modern weaponry against a much more lightly armed opponent, yet one that still had access to some modern weaponry. While the Zulus had a handful of arms, they're more related to your orcs in armament (and possibly ferocity) compared to the British using century-old technologies. In the end, though, the British won. But in all these cases the winner had open country to supply their troops... not a single, restrictive portal. [Answer] The humans would make the orcs pay tribute. <https://en.wikipedia.org/wiki/Tribute> > > A tribute (/ˈtrɪbjuːt/;[1] from Latin tributum, "contribution") is > wealth, often in kind, that a party gives to another as a sign of > submission, allegiance or respect. Various ancient states exacted > tribute from the rulers of land which the state conquered or otherwise > threatened to conquer. > > > The humans do not want the administrative headaches of governing a bunch of orcs over an immense territory. And they don't need to do it. They have a portal that they defend. They will come thru the portal to collect tribute from orc rulers at an agreed time and place. If the tribute is not there, they will come through the portal in force and administer an unholy beating on important things orcish using weapons of mass destructions. When the orcs surrender the humans will explain. again, how it is going to work. The orcs will figure it out, pretty quick. It makes sense. [Answer] # Guerilla war only works if you can fade into a native population. It's an extremely trivial problem spotting life forms. Just scan for heat. Your super magical orcs who have impossible strength will be massively hot, and easy to detect by a plane flying above. They could easily just kill the orcs, and kill any community which had orcs in it. # The North Koreans can just poison the orcish supplies > > speed of a cheetah, the strength of a gorilla, and the durability of an African elephant > > > <https://seaworld.org/animals/all-about/cheetah/diet/> Cheetahs need about 3 kilos of meat a day, and weigh about 50 kilos on average. Your orcs are even stronger, so they probably need more like twice as much meat. Say, 24 kilos of meat a day. That's a lot of food. They need that food to stay active. Where are they gonna get it if the North Koreans poison their food and kill their people? There's a reason we moved away from horses for war. Biological organisms which move very fast need a huge amount of food. That makes supply chains hard. [Answer] # Close to impossible The orcs can never be effective at war. This is because of their physical prowess. Lets see their physical attributes: * 2,5m tall * 200kg * speed cheetah * strength gorilla * durability of an African elephant Let's skip over the physical impossibly of such a creature. To sustain such creatures we need a lot of energy. Multitudes more than a single human needs. That means you need a lot of husbandry to have enough meat and plant matter. This would defeat them practically before the war is started. A war as three important elements. The weapon technology. The amount of troops armed or using the technology. And lastly Supply lines. Plenty of wars have been won by disrupting supply lines. A recent example is the Russia Ukraine war where the supply lines were too long and fragile for the Russian army. This lead to hungry and (further) demotivated soldiers. In history we can also see that a lot of wars against Russia have ended in winter, when the supply lines became impossible to maintain. Besides the cold you'll quickly run out of supplies, making any problems you already have much worse and adding triple more. All out war would make the supply lines of the orcs even more vital, as they can carry only so much food and need a constant supply to function. N. Korea can target the supply lines and food production, removing the threat of super soldiers quickly enough. Even if the orcs can send a quick wave if 10 orcs per N. Korean soldier before supplies become an issue they are in trouble. Elephant guns are used to kill the elephant as quickly as possible with as little damage as possible to be able to show off the cadaver. An assault rifle will still kill an elephant just fine. I do think the orcs would win such an engagement with heavy losses, but there is the problem. After they win this first engagement there is still more N. Korean army to deal with. Then they need supply lines. Any disruption of supply lines will kill more orcs than firing on them. Orcs are dangerous, but to control them you only need to control part of their food or water supply. The threat of poisoning a river should be enough to cow them. [Answer] Yes, guerrilla warfare is a type of resistance where the conquered people cede official points of control (capital city, military bases) to the invading enemy, but disrupt the enemy's ability to effectively run the occupied territory by interfering with logistics, signal infrastructure, and so forth, in short targeted attacks followed by immediate withdrawal. The aim is not immediate victory, but an eternal stand-off that eventually makes it not worthwhile for the invader to occupy the country indefinitely\. What the guerrilla soldier needs is superior knowledge of the terrain, the ability to disappear into the landscape, and the intelligence to plan these attacks. If your Orcs have this, they can be successful. The invader need not be an out and out aggressor. They may have been drawn into this mess to ease a post-colonial transition, where the former colonial power is cutting their losses and simply abandoning the territory and forestall another would-be invader to take control. [Answer] Orc puppet government. Any conquest, especially one of such a vast empire by relatively small North Korea, needs collaborators. I think the most likely approach is (1) Offer the Orc queen some guns in exchange for access to lots of resources (IE "we can build mines, oil refineries..."). (2) If she does not accept find some group of orcs who are unhappy. Maybe an ethinic or religious minority. Give them the guns and make a similar deal. Then they take over and provide all the stuff you want. This basic approach, plus maybe touches of air support or training, is quite thoroughly tried and tested in human history. Without doing something like this the Koreans can win any battle, but they cannot police the orc empire (you need police to get taxes). They need an orc puppet government to do that for them. [Answer] Orcs all the way. I'm going to assume that the orcs are as clever as humans, and broadly similar psychologically. I'll also follow the Gate model where the invaders are ground forces only. I'll assume that, miraculously, the human's equipment has been kept running and in good order, unlike (for example) Russian military equipment. While the orcs are "no match for a tank" in the sense that they can't take a tank shell and survive, nor can they punch through tank armour, their physical prowess is such that they can destroy any infantry or light mounted forces with ease. Similarly they can close on and destroy MLR systems , howitzers, machine guns, towed artillery, trucks, tankers and pretty much anything on or off wheels. They can also field an effectively unlimited number of troops. Lets see what North Korea can field. The country has land forces numbering some 1 million, and could potentially increase this number, but this irrelevant, The including about 4,000 main battle tanks of 1950 and 60s design. They also have a number of (say 2000) self propelled armored guns, and maybe 1000 or more APCs It's highly unlikely that they would be prepared to deploy the entire fleet, given their situation with South Korea, but even if they were that's maybe 8,000 vehicles. Now the standard operating mode of modern warfare is "combined-ops" - the infantry protects the tanks, the air-cover protects the ground forces, the anti-aircraft protect the air-force, etc.. The loss of the air-cover might not be too bad, since the orcs don't have flight, but the loss of infantry and support means that the tanks won't be able to advance very far, if they want to retain fuel for maneuvering and returning to base. This means that military operations are confined to maybe 100km of the gate (maybe less considering terrain). But this probably does not matter, for the armour, too, is susceptible to the physical capabilities of our new cousins. Firstly they are as fast as a cheetah - that's 50-80 mph, meaning they can outrun the armour, which will be to some extent bogged down in terrain, but even on roads cannot go that fast (BTR-60, T-62 and ZSU SPG all have a ''top speed'' of 50 mph which will be on roads, probably with tracks off). Once an orc catches an armored vehicle, they can destroy any machine guns from the outside, leaving only the main weapons of the tanks and SPGs. These have a limited number of rounds, and can probably inflict little in the way of net casualties, since the combat orcs will all be either moving fast or on top of other human-occupied tanks. What else can the orcs do? They can bench press about 4,000 pounds due to their gorilla strength. If a tank, and certainly an SPG or APC stops, a dozen orcs at most should be able to tip it over. They would also learn to snap off antennae and obscure windows and periscopes with tar, if this wasn't enough. The orcs would also be able to rapidly build anti-tank barriers, being able to carry large rocks and logs (I'm not sure if they can run at 100 mph while they do this?), dig pit traps, set ambushes, avalanches and so forth, depending on the terrain. They would also have access to smithies and to fire and could build engines capable of targeting a fixed spot with very large rocks maybe several tonnes, which I think would be unpleasant even for modern hardware. The humans could use chemical or atomic weapons, biological would be unlikely to work on orcs, who may not even have DNA, and are unlikely to have one of the same DNA codes as Earth creatures if they do. Since the orcs would not need to field a large army, maybe 50,000 of their 400 million, atomic attacks would not have a significant military impact, and traditional chemical attacks would soon disperse, allowing a new cohort of orcs to take over, if indeed they were not able to create counter measures pretty quickly, or simply run faster than the gas clouds spread. They will doubtless learn to use some of the captured weapons depending on what the humans are good enough to donate, this could include anti-tank weaponry, though clearly there would be limited ammo. They would be able to wear far thicker armour than a human, although they might not consider it worthwhile. They might even be pushed into developing gunpowder for military use, and then there would really be no stopping them. References: * BTR-60 (Wikipedia) <https://en.wikipedia.org/wiki/BTR-60> * List of equipment of the Korean People's Army Ground Force (Wikipedia) <https://en.wikipedia.org/wiki/List_of_equipment_of_the_Korean_People%27s_Army_Ground_Force> * Korean People's Army Ground Force (Wikipedia) <https://en.wikipedia.org/wiki/Korean_People%27s_Army_Ground_Force> * T-62 (Wikipedia) <https://en.wikipedia.org/wiki/T-62> * Cheetah (Wikipedia) <https://en.wikipedia.org/wiki/Cheetah> * DNA codes (Wikipedia) <https://en.wikipedia.org/wiki/List_of_genetic_codes> * Treuchet (Wikipedia) <https://en.wikipedia.org/wiki/Trebuchet> (just over 1000 lb is the best a modern one has thrown, though I seem to remember a <https://en.wikipedia.org/wiki/Volkswagen_Beetle> throwing competition on Scrapheap Challenge. I'm sure Orcs can do better!) * Gorilla (Wiipedia) <https://www.wildgorillasafaris.com/facts-about-gorilla-facts/how-strong-is-a-gorilla/> (somewhat random) [Answer] I don't think they can win. They will probably do well to limit North Korea to a large, walled compound. Assumption: North Korea will have no moral quandary or Earthbound resistance to a policy of genociding orcs. There will be no guerillas hiding in the local population because the North Korean military will be doing its best to completely eliminate all rival factions, including civilians. North Korea will pretty quickly set out to clearcut and burn down everything for miles, both to make it impossible for guerillas to hide and to prepare the area for farmland. If the guerilla attacks are a sufficient menace, I think we'll see the North Koreans setup their new territory as a large walled compound, complete with barbed wire and minefields, and this may be how they proceed in general: expand to a new area, burn everything down, wall it up, drop minefields outside, start planting crops. Human guerilla war relies on the invaders just not being too nasty about it. French resistance had some success against the Germans because the Germans were not willing to simply exterminate every living soul in France. They wanted to capture not just the territory, but the value of the cities and people living in them. North Korea may have no such desire here, with the orcs. Once they get established, they may not be averse to limited nuclear strikes on large orc populations (limited only so they don't spoil the environment for themselves). A better comparison might be European powers versus the natives of the western hemisphere. The ruthlessness of the invaders meant that guerilla warfare didn't work very well. I think the orcs' best bet is probably not guerilla warfare, but massed wave attacks, and the sooner the better. If literally a million orcs don't mind suiciding into the area (that is, they don't mind starving to death even if they win) then I think we'd find the North Koreans simply don't have enough ammo or equipment to deal with it. [This occasionally comes in up zombie novels. The zombies are stupid and limited strictly to hand to hand combat but they win anyway because nobody has the ammo or replacement equipment to kill literally millions upon millions of zombies, and nuking them into oblivion just ruins the planet for the survivors too.] If the orcs are somewhat like the Warhammer orcs and can whip themselves up into a WAAAGH and attack in huge groups then they may simply be able to overwhelm even a modern military via speed, strength and numbers. But that's not really a "guerilla war". [Answer] It is possible, but would require a significant degree of subterfuge - and, likely, outside help. Head-on military conflict in these conditions is impossible to win. Superhuman physical capabilities are a red herring here - the military equipment are power tools, they exist for the sole reason of providing humans with what are, essentially, prosthetic superpowers. And if your current tools are not fit for the task at hand - you change them, it's easy. Orcs are too fast and strong to fight in close range with AKs? Supply your army with heavier weapons and kill any suspicious orcs on sight. Can't distinguish civilians from guerillas? Put the suspect population in concentration camps and exact disproportionate retribution on locals for any losses inflicted by guerillas. You don't really need to stay in close contact with colonised population unless you want to integrate them in your society after all; and you won't want to if majority of them demonstrates open hostility. For example, refer to [English anti-guerilla strategy during the Second Boer War](https://en.wikipedia.org/wiki/Second_Boer_War_concentration_camps). Population difference is also less effective on XV century tech base. Common army size in 1600s was around 30 thousand troops - not because they hadn't enough people to draft into army, but because available road networks, farming technique and transport limited armies by their logistic requirements. Larger armies would have to rely on pillaging their surrounding countryland for food. This is out of the question for guerillas, as it would mean quickly exhausting support of the local population. Modern armies would thus be able to counter numerous, but spread out due to logistics orcs by using their superior mobility to achieve local superiority and destroy them one by one. Thus, the only real option - after initial conflict (which seems all but inevitable), defeated orcs en masse feign loyalty to the invaders. If they are not seen as a threat, eventually orc workers wil permeate the structure of local invader operations - they are strong and numerous, would be a waste not to use it. With a sizable number of such infiltrators, a sudden revolt would allow to take control of the gate, cutting off invaders from their supply lines. Of course, this works only with assumption that the orcs are actually capable to defend the bottleneck that is the gate against attack from both sides. A good way to solve it - if the orcs will be able to destroy the gate altogether (for example - the gate is situated in a cavern under a mountain, and orcs use stolen explosives - or a nuke! - to collapse the cave, burying the gate under millions of tons of rock). This way the orcs would need only to win a single decisive surprise attack, [Battle of Isandlwana](https://en.wikipedia.org/wiki/Battle_of_Isandlwana) style. The advantage modern logistics provide is a double-edged sword - without constant influx of fuel and ammunition, a modern fighting force would quickly lose its combat capabilities. The forces remaining in the orc world will have to surrender. This is a quick and dirty scenario, relatively easy to describe. Another option - that orcs use the time of infiltration to reduce the tech gap, acquiring weapons and training to match their enemies' - for example, a common practice would be for the invaders to set up a police force drafted from local populace, which would supply guerrillas with stolen weapons and deserters as trained personnel (some examples of this could be seen in both WW2 and recent conflicts in Afghanistan; although these structures remained generally loyal to their creators, guerrilla infiltration in them was always significant); another way would be if another gate could be found for orcs to be able to contact other nations on Earth (or maybe some other world) for support. There are multiple examples of this scenario succeeding in history - undoubtedly you heard of them, but I would point out the [First Italo-Ethiopian War](https://en.wikipedia.org/wiki/First_Italo-Ethiopian_War), in which a modern (by 1895 standards) Italian force severely underestimated the degree to which Ethiopian army had modernized in years leading up to war, which resulted in a decisive Ethiopian victory. This scenario is significantly more complex, requiring a lot of time to unfold and involving much less action than political intrigue. ]
[Question] [ Sealing magic is a specialized form of magic that is used to bind and trap supernatural creatures. A mage who specializes in this area would normally use seals against demons, either to contain them within certain objects or to prevent them from crossing a barrier. These seals would block the demon from escaping, permanently keeping it encased within an area or realm designed to contain it. However, there is no multi-purpose seal that is geared for all demons, as the amount of time, expense, and complexity needed to produce such a seal would be astronomical. A seal is specifically designed to match a demon's level of power, turning that very power against the demon when it tries to attack or push through it. A specialist must know what type of demon it is dealing with and discover its attributes and statistics. Once that information is obtained, the specialist must place it within a category and construct a seal based on those parameters. There are three categories from which to choose from. Type A seals are for the high class demons. These are the most ancient and powerful of demons who can level entire armies and cities. Type B seals are for mid-class demons that are average in power. While they are mid-range fighters and not all that powerful, they are still dangerous and can cause significant damage on their own. Type Cn seals are for the weakest demons that are usually the smallest. They are more of a nuisance individually and can be dispatched easily, but in large groups they can become major annoyance and even cause much harm in large groups. As their is no single seal that can accomplish all of these parameters, the obvious solution would be to use them in tandem with each other. This would be done by layering them one on top of the other, with one picking up the slack where the others fail. This solution would prevent any demon from breaking the set combination of seals. What would prevent mages from using this outside the box thinking and force them to construct a single seal based on categories? [Answer] Opposed Polarities. [![enter image description here](https://i.stack.imgur.com/dKT3q.png)](https://i.stack.imgur.com/dKT3q.png) A seal works like a big magnet. Suppose a castle is full of Demons from the Positive (Magnetic) Energy plane. Stick the negative pole of a big enough magnet through the castle walls, and all the demons get stuck to the negative end. Likewise, if a fortress is full of demons from the Negative (Magnetic) Energy plane, they can all be sealed using the positive pole of a big magnet. So why not combine both types of magnet to form a Universal Sealer? Well, you already know the answer -- it's because the two poles will cancel each other out and give you a useless seal. This works if there are two types of demons, but you have three types. In that case, we have something more like color charge than electric charge: [![enter image description here](https://i.stack.imgur.com/1O3oI.png)](https://i.stack.imgur.com/1O3oI.png) Rather than positive and negative sealers, there are now 6 types of sealers: red, blue, green, antired, antiblue, and antigreen. The colors correspond to the three types of demons, so let's call them sealers of type $A,B,C,\overline A,\overline B,\overline C$. A sealer of type $\overline A$ attracts demons of type $A$ and they get stuck to it. 'Sealers' of type $A$ are the opposite -- they repel demons of type $A$. They are Wards rather than Seals, and stop demons of type $A$ from entering an area. Likewise the other two colors will seal and ward the corresponding types of demons. You do not mention type $\overline A$ ,$\overline B$ ,$\overline C$ demons. Perhaps they correspond to the three types of angels. Perhaps they are simply not in the story. Perhaps this is why no one has ever thought about anti-A and anti-B seals? The reason you cannot use two types of seals at once is they interfere according to the addition rules: $$A+B = \overline C \qquad A+C = \overline B \qquad B+C = \overline A$$ $$\overline A+\overline B = C \qquad \overline A+\overline C = B \qquad \overline B+\overline C = A$$ and of course seals of type $A$ and $\overline A$ cancel each other out just like with the positive and negative magnets. The exact rules are unimportant. The takeaway is that if you put two colors at once, they combine such to form a different one of the six basic colors. As a result, you cannot slap all three $A,B,C$ types of seals on the same object and expect them to work. The rules say the $A$ and $B$ seals combine to form a $\overline C$ seal, which cancels with the $C$ to leave you with nothing! You can, of course, create three nested containers, each with a different seal. But this won't work either, as the closer together the containers are, the faster they leak into each other and cancel out. To compensate, you could make the second container much larger than the first, and the third even larger than that. This is no easy feat, because it means the third seal must be very powerful to ward such a large area. [Answer] They interact. You can not just build a seal wall that will keep the demon in. The seal must actively react to its actions. Consequently, one seal treats another as if it were a demon to be contained. The effect is destructive, and since they are as mechanical and unthinking as a waterwheel, they can not learn to distinguish. [Answer] You mention that developing a universal seal to trap all entities would be prohibitively expensive, but I greatly doubt that some bright young magus hasn't at least considered layering as an alternative. So why didn't it work? First, let's define what a seal is. Given the mention of trapping demons in objects, I'm going to assume that a seal is - at least in part - a magical construct that is anchored to the object in some way. Let's imagine that the seal is akin to a complex rune inscribed on the surface of the object, and also an equally complex magical structure that attaches to (or originates from) the rune and permeates the object. The magical structure is the prison that binds the demon while the rune is the control and power source for that magical structure. So what we have here is a fairly standard enchanting problem, with all of the normal enchanting issues. There are a ton of different reasons to limit the number of enchantments, glyphs, wards and so on that you can place on a single object: ### Material Capacity Each material has a limit of how much magic it can hold, and only really expensive materials could potentially hold the magic for more than one Seal. Perhaps the materials that work best for each class of Seal are incompatible with the other classes. Certain ceramics work best for Type-1 Seals, metals for Type-2 and rare (and expensive) gems for Type-3. ### Material Compatibility Using the wrong material makes the spell fail, and the compatible materials for each of the classes of Seal are incompatible with the others. ### Object Structure Spells have to take up space, and the wrong shape of object just won't fit the spell properly. And since the shape of the object helps hold the shape of the spell, just dropping the spell into a big block of mithral or something won't work. And of course all Seals are different shapes. ### Interference This is my favorite options: when spells overlap they interact and interfere with each other. Unpredictable results occur, with extremely bad things happening often enough to make this not just a bad idea but one that nobody (well, nobody who isn't actually trying to destroy the world) would ever consider. (OK, mostly it just all fizzles out. But do you want to risk tearing open a portal to the Chaos Realm when it all goes wrong? Nah, me neither. Bob would though. Don't trust Bob.) This can also stop the creation of composite objects that have the different classes of Seals in separate pieces that, when joined, create the effect of a single object with all three Seals. The spells interfere so strongly that the presense of a Type-3 Seal will destabilize any lesser seal within a few inches. --- I could (and often do) go on, but ultimately the solution I'm proposing is this: your magic system simply doesn't allow it to happen. Each Seal is incompatible with all others in some way, so bringing them together in a single object is just not going to work. Even if your Seals are done as inscribed magic circles on simple stone, any attempt to combine them is doomed to failure. If you want a general-purpose Seal you're going to have to bite the bullet and develop one from first principles. Or maybe talk the gods into doing the hard work, they've probably got a vested interest in stopping Demons. [Answer] The seals are sentient entities. The seal is not some inert carving. The seal itself is an entity, or a part of an entity. The types of seals correspond with specific types of entity and one of these (if the term "one" applies to such entities) is then charged with containing the demon, or an angel, or an ifrit, or whatever work that the seal is supposed to do. To a seal entity, the entities corresponding with the different seals are just more supernatural things to be contained. The different types of seal entities are not friends or even similar. Entities corresponding to different seal types are viewed more or less on par with the demons and angels. They will be contained, or not contained if too strong. There is no cooperation. [Answer] *Seals can* overlap, but doing so kills the caster It's just a popular misconception that seals cannot overlap. But the truth is that there's no rule of magic that prevents it, just as there is no rule of magic that strictly prevents the construction of a "universal" seal. The problem is that each seal releases magical energy into its immediate environment (which is part of how the seal does its job). When two seals overlap, the combined effect destroys the mind and then the spirit of any mortal in the vicinity. The caster, necessarily being present, is inevitably killed. The lucky ones die quickly. As a general rule, people do not engage in activities that reliably lead to their own gruesome demise. They also can't study or experiment with such phenomena. [Answer] Using the wrong seal on a demon actually increases the demon's power, enough to overwhelm proper seal. Seals are actually very precise to their given demon (why there are hundreds, maybe thousands of different seals) and mismatching the demon and its seal will dramatically increase the power of the demon, making it significantly more difficult to defeat and subsequently seal. Curiously, there is actually a seal to use for demons with increased power, but it must match with both the demon and seal. Mismatching layered seals will create an exponentially complex final seal, which is both infuriating to decode (nigh impossible if you don't know every previous seal) and prohibitively expensive due to the seal creation process. [Answer] A seal is basically an inscription made on top of a flat surface. It can be composed of a pigment (paint/ink/whatever), but can also be incised into a material (chiseled into stone or a fingerpaint smear on top of a big paint spill). The materials are also important, for some seals stone won't work, or only certain types of stone work. Or paint won't work. The shape/geometry of a seal is of course very important, and must be inscribed to within some very small tolerance. Certain seals may also have minimum and maximum sizes (beyond those imposed by their practicality). The shapes aren't always purely circular, but they do encompass the full 360° of a circle. (Exceptions do occur, some seals are linear and block doorways.) Generally, no other human/sapient inscriptions can overlap a seal... it essentially changes the seal itself to something else. If the sizes themselves are incompatible, such that the inscription of one seal would overlap another, then it's quite clear why that won't work. Nor can one cheat and move the second seal to another flat surface, one no longer properly traps a demon. Other problems of geometry account for the majority of seal-doubling issues... magic that relies on four cardinal corners is broken when a second seal essentially adds another corner to the mix. Or a seal that must be chiseled in stone no longer provides a flat surface upon which to paint a painted seal. Additional problems can occur with the materials themselves. A seal that must be painted with ochre will contaminate one that must be poured in white sand. Colors themselves are important, but difficult to determine the specifics for when the people from your story don't even have proper theories of optics/color/radiation. In this way, you can occasionally allow for doubled seals when it serves the purpose of your story, but restrict them almost arbitrarily. [Answer] ## Power source problems The Seals cannot intersect without destroying each other, but you could nest them like [Russian dolls](https://en.wikipedia.org/wiki/Matryoshka_doll). With the demon as the innermost doll. Unfortunately, only the innermost Seal will be able to draw power from the demon. Even if mismatched, the demon will use some time to break out of this Seal. At that point, the outside Seals will have faded away from lack of power. Alternative**: Only the outermost Seal will be able to draw power from ambient mana. The inside Seals will fade away. ]
[Question] [ In this world, mutant animals and humans exist on earth, along with regular people. The MC can instantly teleport anywhere on earth freely (his super-power) no matter the distance, and can teleport objects he can touch up to the size of a small house. The technology for mutant society ranges from primitive (bows and carriages) to modern tech we see today (guns, internet, cars, etc), but the normal humans have noticably superior tech like spaceships that can travel to other planets in the solar system, radar that auto detects DNA when something passes through it, machine soldiers sometimes almost indistinguishable from humans, manless self-operating factories that can mass produce stuff like food clothing and vehicles very quickly, supersonic bullet trains, etc. The resources MC has access to personally: TV, PC, basic furniture, heat & air conditioning, alarm system, cloth-like body armor that defends against small-arms fire and blunt force (like falling off a building), a cell phone, a utility belt with a variety of situational items, a powerful AI inside his sanctuary very similar to a person (which he can talk to through a device on his armor). He doesn't want others to access or know about his sanctuary, both humans and mutants. What is a feasible place for him to live? The mutants have various abilities including but not limited to: flight, super speed & strength, project lightning & fire and other elements, telekinesis, etc. It's a post-apocalypse, mutants live in areas outside civilization, like forests or abandoned cities, while humans band together in fortified areas. [Answer] Hide it in plain sight. You seem to have reasonable carte blanche when it comes to the secret base. One problem with the ideas so far is that you could be tracked down by your use of electricity, water or heat. So instead you build an apartment complex with several tenants. You own an appartment on the bottom (or if it's luxurious enough you own the entire bottom). Beneath the utilities basement you have another basement where you will build the base of operations. Perhaps make it some off-the-books work with the contractor so it doesn't show up on the building plans. You make sure the ventilation system of the building is connected to the lowest basement. You then do some work so the electrics and water of the basement are drawn from the apartment you own. This way any electric and water usage will not be unnoticed. Make the bottom basement a gym for a short time (or have illegal activities take place there, out of your knowledge of course). Eventually the gym will be shut down for monetary or legal reasons and you brick it up completely. Now you have a basement that is there, people even know it's there, but it's no longer accessible and in use, right? There's hundreds of small sections no longer in use all over the city, doors and rooms that some people know technically exist but you walk past it because there's nothing there. It's ventilated, it has running water and electricity that are billed to an address, and since it's an apartment complex no one can wonder why there is random heat or electricity at that point, especially since it's right beneath the utilities basement where you likely have the central water heater and electric circuits for the building. And hey you live there, so you can also sit back and relax whenever you feel like it. [Answer] We'll assume that our teleporter can carry at least some light items with them while teleporting; otherwise, establishing a secret hideout is going to be pretty darned rustic. Were I the teleporter, I'd probably establish my hideout in an inaccessible forested extinct volcano, a place like [Mount Lico](https://www.techtimes.com/articles/231554/20180702/scientists-explore-secret-rainforest-hidden-in-volcanic-crater-in-africa.htm) or the [Kahuku Forested Pit Crater](https://www.nps.gov/places/forested-pit-crater.htm). Such places would have the advantage of being inaccessible to all but the flying mutants, and the dense forest would allow the teleporter to build a habitation that would be hidden even from them. Unlike glaciers, outer space, or cave systems, they wouldn't have issues with temperature, breathable air, or water supply. In tropical zones, solar panels could supply electricity. They could even have a garden. [Answer] Kerguelen Islands, Southern Indian Ocean > > [Situated more than 2,000 miles away from civilization, these islands in the southern Indian Ocean are also known as the Desolation Islands due to their incredibly remote location. Grande Terre is the biggest island in the volcanic archipelago, a French territory consisting of 300 islands covering an area about the size of Delaware. > There are no native people living in the Kerguelen Islands, but a small population of scientists ranging from about 50 in the winter to 100 in the summer live and conduct research in the only settlement, Port-aux-Français. The only way to travel to the Kerguelen Islands is by a ship that leaves only four times a year.](https://www.treehugger.com/most-remote-places-on-earth-4869276#:%7E:text=The%20volcanic%20island%20of%20Tristan,on%20Earth%20inhabited%20by%20humans.) > > > Find an island with no scientists, or if there are scientists go about 60 miles away and there is virtually no chance of getting found. If you do get found you have three months to leave. making it hard to get to you doesn't matter, mutants and dedicated humans will get you eventually, the only way to be sure no one can get to you is make it so they don't know where you are. [Answer] Imagine a building and a hidden room, without windows or doors (but with ventilation and with power, if there is still such a thing). Everybody who thinks about complete floor plans (if they still exist) will realize that there is a cavity somewhere, but there will be perfectly logical reasons why it is inaccessible now. Perhaps an elevator was added at a later time, and it blocked access to one of the flats. Or there was a swimming pool added at a lower floor, and it blocks access to yet another set of rooms. [Answer] There are several excellent examples given throughout the course of the Jumper series by Steven Gould (I highly recommend reading all four books in the main series whenever given the opportunity). The main character's first "base" is simply a nondescript apartment in Manhattan, where he has walled off a closet so that only he can access > > the funds acquired through his bank robbery (he previously hid the money in duffel bags in the ceiling of the library in his home town). > > > He also rents an apartment in a college town, though this is primarily to feel close to his girlfriend who attends the college. He eventually develops his first true secret base, a cliffside cave he walls off deep in a wilderness area in Texas; he also acquires a few ravine oases in the same region that he initially uses for swimming, but eventually uses as a convenient place to > > deposit terrorists and federal agents while figuring out what to do with them. > > > The end of the second book is marked by the decision to purchase a house isolated somewhere in the Canadian wilderness. This house was built by someone else, uses geothermal energy for energy independence, and they never access the internet or phone system from it. The third book tackles what is actually a bigger problem: connecting back with society after living anonymously on the fringes. Focusing primarily on the daughter attending high school using an assumed identity and detailing a bit of the technical tricks used to dodge digital detection, we also get to see a glimpse of the main characters' humanitarian efforts: warehouses scattered throughout the world, filled with bags of humanitarian items that can be carried by a single person, psychological tricks used to deflect attention from someone who could've sworn there wasn't somebody standing there a moment ago..... The third book also introduces the concept that > > the ability to match inertial frames implies the ability to change velocity while jumping; > > > but I include it in this paragraph because it is in the fourth book that the daughter uses this ability to > > establish her own space program. > > > Items like air pressure and decompression are mentioned briefly in previous books, but here they obviously take center stage in a book that > > puts the ultimate teleporter's not-so-secret-but-very-hard-to-reach base in an inflatable habitat in orbit. > > > Also meriting brief mention is the possibility of purchasing a defunct hotel in some unknown urban area; and the close, which sees > > the daughter handing a friend a container of soil from Mars > > > can inspire other ideas, which may unfortunately be a little too far out of your stated scope. [Answer] Deep under the ice The power to teleport anywhere instantly together with an object the size of a small house is very, very powerful. It means the MC (Mutant Character?) can take basically anything she/he desires that conforms to the weight limit. First go to either the North or South pole and teleport some blocks of Ice away. Next find something like a small nuclear bunker or simply a box of reinforced concrete. Do make sure it can stand up to massive cold, but it's likely not going to be too cold due to the insulating properties of ice. Important is that it needs to be fully waterproof. Possibly you need to teleport it elsewhere first to treat it to be waterproof, or find somewhere that already has happened. Make sure that there is plenty of insulation on the inside. This is not only to prevent heat from escaping, it is also to prevent the ice surrounding it from melting and detection by heat sensors. Next you install some pipes for air ventilation. Thanks to heat exchange pipes you can have normal air come in and cold air go out like the blood veins in your arms and legs exchanging heat. Install a few pumps and some air reservoirs and you can fill any remainder of the hole with water or ice. You can also still increase the size of the sanctuary at this stage with modular components. Best would be to stack the modular components to make the sanctuary profile as small as possible for the most likely eyes: satellites from above. Also make a pipe down if there's water there, or sideways for a water intake. With that done you can proceed to get two incredibly important components. Hydrogen electric cells and electrolysis machines. The one turns water into hydrogen and oxygen. One you can breathe while the other you can burn for heat/cooking or put into the hydrogen cells for electricity and water. This is similar to some submarines and leaves basically no trace of obvious waste. Extra energy is still needed from, for example, a deep-sea tide generator or the like. Something that can cleanly produce energy away from prying eyes. Alternatively you just teleport some hydrogen canisters with you once in a while, making your base more stealthy. With that sorted you can potentially lock down the whole sanctuary where nothing goes out temporarily. You store excess air and personal waste in the canisters earlier installed, while still being supplied with oxygen and electricity. Now you've got a functioning base. Deep under the ice it's unlikely to be seen by satellites and the cold prevents most people from going there. Best would probably be the south pole, where the structure can rest on the island underneath. This will support the structure as well as hide it better to things trying to look through the ice. You can also tunnel under the base to try to use geothermal power for the extra electricity. Furnish it, paint it, make it homely and add the AI. You're ready to stealthily conduct any operation staged from one of the most remote and secluded areas in the world. It is possible with the aid of teleportation and rudimentary skills in construction to make this yourself, although electrical skills for the advanced stuff is required. Possibly the AI can make exact plans for the MC to make it as simple as IKEA (Where is that red cable!?). Only one problem. If you're talking to your AI it means transmission. The transmission can't "hide" in the plethora of signals sent from other sources, as there are practically none on the poles. Any such signal would stand out and be investigated. Otherwise you can't get much more secluded that this. [Answer] Let the villains plan and build and pay for the secret hideouts. Move into one (or more) after the villains are done with them (incarcerated, dead, amnesiac, etc). Block access so that henchmen and previous occupants cannot conveniently return. When a powerful villain returns and wants their lair back, move on to another "abandoned" hideout instead of fighting for the real estate. Alternately, the teleporter can use their detailed knowledge of the hideout to trap Mr Badguy during their next conflict. In the meantime, clever villains will have arranged ways to keep the utilities turned on, so the teleporter can use that. The teleporter can sleep in Mr Badguy's bed, eat Mr Badguy's food, and peruse Mr Badguy's internet...possibly for many years until Mr Badguy's untraceably hidden funds are exhausted. [Answer] / manless self-operating factories that can mass produce stuff like food clothing and vehicles/ Hide out in there! I like manless because I don't need no sausage party in my hideout, and I like stuff like food even if it is mass produced. I don't want to hide out anywhere that I run out of food and water, ever. Running out of clothes would be ok but still some swanky clothes make a hiding hero feel put together. As regards vehicles I would set up a race course in there to test out the various vehicles including those 3-wheeled cars (not the Mr Bean kind; the sweet kind). The AI in charge of the factory is romantically involved with the powerful AI I have in my hideout, who is named Powerful. I have to remind Powerful to treat Factory right and not to screw it up because the free food and clothing and vehicles thing works for me and it would be hard to get done anywhere else, or at least not done so well. I tell Factory that because I think most people don't appreciate how hard it is to run a manless factory. "Factory" is such a harsh word but the factory is actually an awesome place to live. ]
[Question] [ I'm writing in a fantasy setting. My goal is to have noble houses which derived from monarchy but not a monarchy itself. My idea for what happened is this: Once upon a time, there was monarchy--there was a king and his subjects were given noble titles and territories. Then, along came a bunch of wizards, who became so powerful that they threatened to overthrow the king. Before they tried, however, the wizards promised the nobles that after the king is no more, the nobles will retain their titles, their lands and pay less taxes. (also, if anyone dared oppose the wizards, they'll have a bad time because the wizards had better weapons than the nobles.) Thus enticed and threatened, most of the nobles chose to do nothing while the capital is seized and the kind overthrown. Ever since, the wizards ran the capital, but the nobles continue to exist as centers of power, even though there will be never be another king who might officiate their titles. I want to know if this is plausible, specifically, I want to know if it makes sense for the nobles to stand idly by while the wizards overthrew their king. Assuming that it will be costly but not impossible for the nobles to fight the wizards. Would the absence of a king completely invalid the nobles' power, and therefore make the battle to preserve monarchy obligatory for the nobles? [Answer] ## If wizards just replace the king but leave local power to nobles, nobles would have little reason to rebel I assume, as you speak about kings, nobles and tag it medieval-europe, that the current political regime is feudalism. Small nobles swear fealty to counts, count swear fealty to duke, duke swear fealty to king (ranks may vary, but you get the general idea). This was done for a reason, a single king can not rule a whole kingdom, you need to delegate power. Feudalism was an effective way, built on a pyramidal scheme. The wizards probably still needs to delegate power. They may not be enough to replace all nobles, lack legitimization, and they may just be unable to rule the country if they replace the nobility with themselves or nothing. As only the top of the pyramid is replaced, the base still is the same. if you are a count, what does it matter who is the king? You swore fealty to your duke and still have your lands: very little changes for you. If you still keep the power, you just have too much to lose and too little to gain. If you rebel and win, you keep a fancy title, hurray. If you lose, the wizards will seize all your titles and your wealth. Not hurray. Nobles have power from feudalism, not monarchy. Just keep feudalism, with a council of wizards at the top instead of a King, and the nobles would accept it. [Answer] G. Tomasi di Lampedusa wrote "[The Leopard](https://en.wikipedia.org/wiki/The_Leopard)". > > The novel is the story of Don Fabrizio Corbera, Prince of Salina, a 19th-century Sicilian nobleman caught in the midst of civil war and revolution. As a result of political upheaval, the prince's position in the island's class system is eroded by newly-moneyed peasants and "shabby minor gentry." As the novel progresses, the Prince is forced to choose between upholding the continuity of upper class values, and breaking tradition to secure continuity of his (nephew's) family's influence ("everything needs to change, so everything can stay the same"). > > > That last sentence is the key, and it can also apply to your case: > > If we want everything to stay as it is, everything has to change > > > Nobles do not need a monarchy to legitimate their power, if they have some other way to justify it: be it wealth, be it industry, be it a republican party. The real hidden source of power is money. [Answer] Look at power, not legitimacy. In theory, the king owned all land and gave fiefs to vassals, who owed fealty (and taxes, and military services). Those vassals also got noble titles and a complex hierarchy. In practice, the king was unable to control the whole kingdom personally, and had to delegate some authority. When one of the vassals died, there had to be a new one, and not selecting the heir of the dead guy would have caused trouble. Every now and then, a king might have wanted that trouble, perhaps to cut an overly powerful family of vassals down to size, or to get lands to reward a personal favorite. Assume that each of the senior noble families controlled a relatively small part of the kingdom -- small enough to manage it personally and to keep their own vassals under control. Keep things that way for many decades, possibly even centuries, and you have a tradition where formal fealty is given to the king, but the senior nobles are very much in control of their own fiefs. Perhaps there were several incidents in living memory when powerful nobles removed a king and formed a "regency council" for a more pliable heir. Then the wizards came along and suggested to some nobles to do away with the current king. Not a radical idea at all, as long as the forms are preseved. Make sure that the king and credible adult, male heirs die, form a regency for some figurehead who is a baby, or a woman, or both. --- Note that my use of genders in this scenario plays on modern conceptions of medieval prejudices. Make a conscious decision how that is handled in your setting. [Answer] As other answers have indicated, it is certainly possible to have an aristocracy in a republic. I'm not sure what historical time period your fictional setting best equates to, but if you want specifically medieval historical parallels (as opposed to Early Modern or Victorian ones), the nearest thing to what you're describing probably occurred in Italian city-states such as Florence, which managed to throw off the rule of feudal princes but maintained a role for local nobility in their political system. Nonetheless, I think it's wrong to suggest that your wizardly coup could would succeed without a fight in most pre-modern societies. Simply put, legitimacy matters, and your mages don't seem to have any. The power of pre-modern monarchs to command their subjects was fairly limited, but they did have a tremendous amount of sacral authority as God's chosen representatives on Earth, which meant that overthrowing the monarchy could not be accomplished without causing severe social and spiritual upheaval. Even in the 17th century, rebels in England and the Low Countries were careful to couch their republics as a restoration of ancient rights and traditional constitutional forms, not as innovations. Why is this important for the stance of the nobility specifically? Well, the limited coercive capacities of a pre-modern state made it more - not less - important for power-holders to be able to claim some plausible moral justification for their rule. Medieval society depended on hierarchical bonds of trust and reciprocal loyalty, and thus if the nobles refuse to defend their king at all, then they are still undermining their own position even when their lands are not directly affected. If the higher lords fail to honour their sworn oaths to defend the monarch, why should their own vassals feel obliged to honour the oaths they have sworn to them? Here is an article explaining in more detail how the fealty-based political system of a feudal polity actually works, and how the kind of no-holds-barred treachery practised by nobles in Game of Thrones would be nonsensical and self-defeating in real life: <https://acoup.blog/2019/06/12/new-acquisitions-how-it-wasnt-game-of-thrones-and-the-middle-ages-part-iii/> Plus, even if you decide that your nobles ARE all faithless schemers, it still seems likely that at least one of them would try to fill the king-shaped vacuum in the realm by claiming the throne once it gets forcibly vacated. Of course, if the wizards have enough raw power then probably they can browbeat or bribe the aristocracy into quiescence eventually, after which they can start manufacturing their own forms of legitimacy. Nonetheless, I find it implausible that the nobility could simply be bought off with a tax cut without putting up any significant resistance. So the answer is: yes it's possible, but that doesn't mean it's likely. [Answer] The nobles might worry the same could happen to them. I find it plausible that nobles might be talked out of supporting the old king because the wizards promise them everything will stay the same. If that is what you need for oyur story it makes sense and other answers have said that. Some nobles, though, might see the writing on the wall as regards their own prospects. The only thing maintaining the aristocracy is their solidarity. They have no particular skills or gifts, just money and inertia. Maybe some nobles have magic users in their own territory. If a magic user can kick out the king and other members of the aristocracy do not help, that same fate could befall any one of the nobles. A magic user could kick him out of his ancestral estate and the other nobles nod and smile. Nobles might decide that it is bad precedent to let a bunch of riffraff magicians kick out the king, and go to his aid. Or for your story it might be better if just one noble house did that. Magic users wind up in that house as well as the king's palace. [Answer] ### You're story setting is a metaphor for current wealth divide I think self interest and self preservation would lead to a path similar to how you have described. In public nobility would declare full allegiance to the king but if the wizards can launch an overwhelming attack on the king and inner circle with superior weapons few would choice to join them in death after the battle is effectively already lost. King dies. Rich keep wealth. Rich pay guards. Guards prevent uprisings. The rich bless poor people with token amounts of money known as trickle down economics. The rich live happily ever after. I suspect you'll get a transfer to a more "modern" wealth divide situation. Wealth creates more wealth, inheritance passes wealth onto children, the titles just morph into modern "nobility" titles like "billionaire". A billionaire is able to invest money and let it grow into more money, such that it can be divided between their children, allowing a noble to bestow the title of "billionaire" onto their children. No king needed in the process of granting the noble title. [Answer] You don’t need a monarch to have nobles. Look for example at [this Wikipedia link](https://en.wikipedia.org/wiki/Knights,_baronets_and_peers_of_the_Protectorate) listing the noble titles conferred by the successive Lords Protector as the heads of the Republican Commonwealth of England during the Interregnum following the English Civil War. And pre-existing noble titles established under the monarchy were not abolished. ]
[Question] [ So, a little while back I suggested Chinese-style paper armor as answer to [this question.](https://worldbuilding.stackexchange.com/a/186337/70058) While it was well liked, a couple people mentioned that in the MythBusters test it didn't hold up very well when it got wet (translation: it slowly disintegrated). With that in mind, what are some Song-dynasty appropriate ways to waterproof a set of paper armor without making it ponderously heavy? [Answer] Use the same method the Chinese used to protect leather armor Lacquer > > Infantry wore suits of lacquered rawhide, hardened and lacquered leather [or partially tanned rawhide?].... ([Source](https://en.wikipedia.org/wiki/Chinese_armour)) > > > That quote refers to armor from the Han dynasty, a thousand years earlier than the Five Dynasties and Ten Kingdoms period when paper armor was invented ([907-960 A.D.](https://en.wikipedia.org/wiki/Chinese_armour#Five_Dynasties_and_Ten_Kingdoms_(907%E2%80%93960))). Lacquer was an incredibly important part of Chinese life, technology, and economy and it would be very natural to coat the paper in it. Benefits: * Rigidity. Not only is this a benefit for deflecting weapons, the rigidity would also increase the lifespan of the paper armor, which won't deal well with flexing. If you coat the paper with something that allows it to remain flexible, the paper will eventually seam and separate along the flex lines. * Mold and mildew control. Any moisture in the paper is bad, notably because it will allow mold and mildew to set. Not only will this destroy the paper more quickly, it would harbor illness and disease. Lacquered armor would be sealed against moisture. * Retained shape. The armor will be useful for a longer period because it will better retain its shape. Any solution that allows the armor to flex will also allow the armor to lose its shape, and therefore become ill-fitting. This lowers protection and increases discomfort, resulting in lowered fighting ability. * Lifespan. Who doesn't want to hand their armor down to their descendants? While lacquered armor is likely to be destroyed by use anyway (what armor eventually isn't?), the lifespan of lacquered armor would permit it to be used by multiple generations. Or, perhaps more valuable to the State, to be issued to new warriors (after patching a few holes). * Aesthetics. The color in and under lacquer will last a long time, meaning the armor can be beautiful and reflect the colors and designs of the affiliated warlord. One last thing... In reference to your statement that MythBusters said the paper didn't hold up well when wet, we have the following: > > Later Ming texts provide descriptions of paper armour. One version was made of silk paper and functioned as a gambeson, worn under other armour or by itself. Silk paper could also be used for arm guards. Another version used thicker, more flexible paper, hammered soft, and fastened with studs. *It's said that this type of paper armour performed better when soaked with water.* ([Source](https://en.wikipedia.org/wiki/Chinese_armour#Paper_armour), emphasis added) > > > If that reference can be believed, it might be that MythBusters didn't use the same armor-making methods the ancient Chinese did. Or, perhaps more likely, they made the assumption that the armor was expected to last beyond one battle. The whole point of paper armor is that it's cheap and fast to make. Which might be the reason it wasn't lacquered historically. What's the point of making something last that isn't designed to last in the first place? [Answer] Wax. [![crayons](https://i.stack.imgur.com/N0Rfv.jpg)](https://i.stack.imgur.com/N0Rfv.jpg) When I was a kid and used to make paper boats by folding A4 sheets, I found out that scribbling one side with [crayons](https://en.wikipedia.org/wiki/Crayon) would make them float quite longer in the fountain. As a bonus it would allow for having fancily decorated armors. [Answer] I suspect that there is not one answer to this question as paper was used over a long period of time and would have gone through several changes. Evidence for this is paper thin (pun intended) and lot just circle back to the mythbusters episode, but I have managed to find a couple of sources that give some indication of how it might have been done. From this I have two methods that seem to be confirmed via historic sources and I have an unsupported idea from my own supposition. The first of these is waterproofing using lacquer (a la JBH's answer) and resin. One of the things I found was that Korean paper armour was considered to be particularly fine, and was a common import/tribute, so looking for Korean Paper Armour I managed to find this: <http://cejsh.icm.edu.pl/cejsh/element/bwmeta1.element.desklight-9260b5e1-b88f-4bf8-9521-9cd0ea330675/c/randall.pdf> (Note link downloads a PDF) It references a report on the materials required to make 120 sets of paper armour and works out there is roughly five litres of varnish and one of lacquer (which lines up with what what JBH has suggested). In the same article though it notes that even with this mould and mildew was a persistent problem that was inspected for. The second is cloth. In this source: <https://www.academia.edu/4409977/Practically_invulnerable_Chinese_paper_armor> There are a lot of references to the armour being constructed of alternating layers of of cloth and paper, essentially creating a gambeson with paper additions. In this situation the waterproofing, or more likely stabilisation of the paper when wet, would have been provided by the cloth layers, potentially with whatever waterproofing methods were using on cloth at the time. Of these it looks like cloth settled on being the preferred option as the sources indicate that is was still around in the 19th century to be tested against western firearms. However this might not indicate effectiveness of waterproofing (or defence) rather good enough performance combined with ease of manufacture. My own supposition is that are that there were designs that were inherently waterproof, though from different methods. This is my own supposition, from a couple of unsupported lines I read while finding the sources I have cited, so take these ideas with a grain of salt. The first of the two was that paper armour was something akin to Geek linothorax (<https://en.wikipedia.org/wiki/Linothorax>), essentially impregnated with glue before being layers upon layers being being stuck together and finally beaten to restore the paper's flexibility. In this method the glue becomes the waterproofing. The other one is that we are thinking of the wrong sort of paper. A couple of places on the net indicate that barkcloth, a material made from beating parts of bark into sheets. Others, however, reject this as it as primary sources use different terms for paper and backcloth (<https://greatmingmilitary.blogspot.com/2015/02/paper-armour-of-ming-dynasty.html>). Even if it was true paper that was used we could be looking at a type of cloth based paper like that used in US currency which holds up fairly well to being wet, although it's not great for it. If these were used I doubt they hung around. The glue type would have required a lot of materials and been time consuming to make, and would have likely been out performed by metal. The cloth type would have probably been prohibitively expensive as the best cloth base would have been silk which would have been expensive and if you have silk you might as well make a silk gambeson instead. [Answer] Emulate a straw cape. [![prince ashitaka](https://i.stack.imgur.com/iTbd8.jpg)](https://geekdad.com/2016/02/my-ashitaka-cosplay/) A [mino](https://en.wikipedia.org/wiki/Mino_(straw_cape)) is a Japanese straw cape, as worn by Prince Ashitaka from Mononoke Hime above. The long firm straws are water repellent. > > Rice straw has water repellent properties. Raindrops striking a mat of > straw will tend to flow along the fibers of the mat, rather than > penetrate underneath it. > > > Your armor is made in a way to emulate straw. Long strips of paper are folded on themselves and pressed, or perhaps rolled very tightly until they are like straws, or perhaps pine needles. The strips are arrayed in an overlapping fashion on the outside of the armor to shed water before it can soak in. ]
[Question] [ I'm designing a roleplaying game set in a colony in a distant star. I'm no scientific expert and I don't want the setting to be hard sci-fi, however, I do want it to be credible. What plausible reasons could there be for a colony on an alien planet to lack transport infrastructures but still have access to other technologies working to ensure survival on that planet, assuming a tech level that would enable us to set up a colony on a planet light-years away? Here are a few constraints: * Humanity reached the planet on an embryo-ship. * The A.I. androids started building the new colony. * Humanity was raised and educated by A.I. androids. * Of the initial 50,000 embryos, only 10,000 were raised by the A.I. for unknown reasons. * The first humans shut down the A.I. androids (there are a few rogue ones). * These 10,000 humans are now trying to get the half-finished colony under way to prepare it for the second wave: the remaining 40,000 embryos. * Transportation between settlements must be sparse. * There must be different settlements around the main settlement (no more than 2-3 days journey), much like the Old West. All these ideas are subject to change if not feasible or plausible. Again, this will not be hard sci-fi, more like space fantasy. [Answer] New Colony Spaceship have limited cargo carrying capacity. Any vehicles sent would be few in number and allocated for set tasks. People would have to walk everywhere until the mining, smelting and manufacturing has enough surplus material to build transportation. Many many other projects would be higher priority than transportation. Quite possibly horses could be sent because they can be bred thus not require the materials. Horses can be used for farming, transportation as well as eaten. [Answer] *AI androids were* the transportation For a sophisticated civilization capable of interstellar travel and colonization, there was no point in creating vehicles dedicated to human operation. While modern humans use "cars", "trucks" and "helicopters", this futuristic civilization uses multipurpose robots, capable of performing transportation, and much more. Maybe not quite on a level of "Transformers", but you should get the idea. When all androids were shut down, that effectively robbed the colony of all methods of transportation. Single point of failure, some say, but this is how the story goes. [![enter image description here](https://i.stack.imgur.com/CRUcm.gif)](https://i.stack.imgur.com/CRUcm.gif) [Answer] Microbial corrosion. [![microbial corrosion](https://i.stack.imgur.com/CLr68.jpg)](https://i.stack.imgur.com/CLr68.jpg) <https://c1sinc.com/blog/mic-microbiologically-influenced-corrosion-fire-sprinkler-pipes> This is a wet planet. And the microbes there like metal. Microbes on earth like metal too but on this planet the microbes will add oxygen to pretty much any metal. You can have electronics if you keep them sealed and dessicated. But transportation tech as developed on earth is exposed to the elements and once the microbes get in, they eat, and eat. The starships they landed in are heaps of oxides. The vehicles your colonists brought are also useless. Engines with metal parts to contain high temperatures or resist high stresses are prime fodder for the microbes. Metal firearms are gone. Wood can be used and your colonists have wood frame dirigibles. Wooden bikes are out there, using fiber chains. They are working on ceramic engines but it is slow going when the casting vessels keep oxidizing away. [Answer] Local transport infrastructure will reflect the size of the local population, its geographic distribution and technology. 1. Population density and location. The population of the planet will initially be concentrated around the main landing area. Outlying settlements will probably be small and not to far from the 'spaceport' simply because unless some essential resource is located far away there's no real reason for them to be anywhere else. If you do have essential towns built elsewhere they will tend to follow the same pattern, one local big center surrounded by smaller townships within easy transport distance. 2. Resources will be allocated to key infrastructure first- hospitals, schools, essential industries etc. so big modern transport infrastructure waits till there is a population that both needs it and can pay for it. 3. Transport vehicles sent to the planet or built there will designed to cope with local conditions. So for example with no road/highway network you will have heavy duty off road vehicles operating on dirt tracks. No airports VTOL aircraft. No railways - boats/barges Also look at the history of the European expansion. When horses were the dominant form of transport small country towns tended to be about half a days cart ride from each other. When railways came along all the little towns disappeared and consolidated around trains stops because the economic justification for their existence disappeared. Then along came cars and and populations concentrated again with railway towns disappearing/shrinking and big rural centers growing a few hours car ride apart. [Answer] I like Thome's answer, but here is another one: Power Systems and Fuel** Right now, most transportation systems run by burning hydrocarbons. Others like direct electrical power (mostly trains), batteries (cars and bikes) and wind (recreational craft) are much less common. To get gasoline, diesel, and kerosene, there have to be fossil fuels, drill rigs, and refineries. High startup costs. The alternative might be biofuels, but that competes with other uses of agriculture. Or water electrolysis to create hydrogen. Explosive and difficult to handle. High-capacity batteries are quite difficult to produce and they tend to have a limited lifetime. So assume that they brought a number of vehicles with them, complete with spare part kits and initial fuel stocks, but only a very limited fuel production capacity. Solar power is used in some specialized roles, but they can't power a truck, jeep, or tractor. Perhaps the auxiliary motor of a sailboat. Or flimsy drones. Month by month, the colony administration must allocate fuel to farming, construction, emergency services, and other uses. those "other uses" don't get much unless the geologists make a real good case for some prospecting run, or the like. [Answer] The colony is small, and everything is at short distance, around the spaceport through which all communication [with other planets, as there's nobody else on this planet] happens. Why would a transport infrastructure be needed, if the only place you might one something/someone is already the one we are on? [Answer] ## The androids did not create any transportation infrastructure They androids were supposed to build roads, rails and vehicles. But you already established that they were everything but reliable. So the transportation infrastructure could be yet another thing they were supposed to take care of but didn't. The new colony already starting 80% understaffed. And then they had to deal with a rogue AI crisis and the subsequent challenge to continue their struggle for survival without the android servants they expected to help them. There were too many other concerns which had higher priority than correcting that mistake. When vehicles were delivered instead of built on site, then it's also possible that most transportation vehicles were destroyed during the AI uprising. Infrastructure is always an investment into the future. When you are fighting for survival, then other concerns are often more pressing. That road network between your farms, granaries and canteens might surely enhance the efficiency of your food supply, but it's of no use when you starve to death while you build it. [Answer] ## Change of Plans The AI planned for conditions that never came to pass, because the humans took things in a different direction. Maybe the AI was planning on a hyper-dense arcology, where all 50k humans in the initial colony would live in a single building or small group of buildings. Transportation would be mostly by elevators and sky-bridges. The Human rebellion that turned off the AI changes everything. Now, the arcology won't work because [reasons]. Humans return to a more traditional kind of life, with a central urban core surrounding by agricultural communities. There are lots of [reasons] why the arcology doesn't work without AI. I would probably pick food, since it's so fundamental. The hydroponics / waste recycling / microbiomes required for arcology food production are just too hard without the AI, so the whole plan has to change with the end of the AI era. [Answer] [The city of Norilsk in Russia](https://en.wikipedia.org/wiki/Norilsk) might be what you think of. > > The city is served by Alykel Airport and Valek Airport. There is a freight-only railway, the Norilsk railway between Norilsk and the port of Dudinka. There is a road network around Norilsk (such as the A-382 which links to Dudinka and Norilsk Alykel Airport), but no road or railway to the rest of Russia. In essence, Norilsk and Dudinka function like an island. Freight transport is by boat on the Arctic Ocean or on the Yenisei River. > > > Reason: > > Despite being located inside the Arctic Circle, Norilsk has a subarctic climate (Köppen climate classification Dfc) with very long, severely cold winters and very short, mild summers. It is covered with snow for about 250–270 days a year, with snow storms for about 110–130 days. > > > So while they can move inside the city, moving outside is mostly a no-no (besides airplane). [Answer] ## Quarantine Protocols The settlements have been designed to start up independently with minimal interaction, so that any biological threat affecting one is not spread to the others. This made transportation infrastructure unnecessary until a certain point in development and resilience would be reached. Unfortunately, that point was not reached according to the A.I. When humans decided to venture out and travel to the other settlements against the directions of the A.I., it sent out bands of androids to enforce quarantine protocols, by tracking down and capturing or killing offenders. These tracker androids operate independently and thus survived the shutdown of the main A.I. Travelers between settlements risk attack by the androids at any time. Those caught relatively close to their origin city report having their vehicles, weapons, supplies and communications gear taken before being turned back. Those caught deeper in the wilds never return. It is unknown whether they are captured or killed outright. Attempts at building any transportation infrastructure have failed due to sabotage and attacks on workers and supply trains. Despite all this, people travel. The successful ones advise to travel light and on foot to evade detection. It may take days instead of hours, but the chances of arriving safely are much higher. All of this should support the Old West vibe you're going for, though I wouldn't go as far as to call the independent androids "inde-ans". People on foot have some freedom of movement, but transporting cargo becomes a real tense affair. Finding out where the androids are based and what happens to captured humans is an option if you want the transportation issue to be resolved at some point. [Answer] Lack of suitable raw materials Lack of raw materials on the planet to construct and maintain such an infrastructure. This idea comes to me from Robert Heinlein's "Farmer in the Sky", where a colony is severely constrained by a lack of suitable building materials on what was a lifeless world. There were no trees from which to harvest lumber and no extractable metal from the crust. Buildings were hewn out of rock. The only metal-based products available were what was brought from Earth. What little mechanical transportation that was available was rationed among the colonists, so while there were "roads", there was little in the way of traffic to make them more than just marked areas of rock. [Answer] Disassembling a colony ship for parts once it reaches its final destination is basically a sci fi trope at this point happening across the entire genre, from TV shows like Star Trek to video games like Stellaris. Split your embyros up across multiple ships and have each settlement be the results of the colony ship which brought that particular group, and the distance between them was to make sure they didn't accidentally land on top of each other. You could say they have multiple ships so as to to increase the possibility of the embryos arriving, so one ship failing doesn't doom the whole colony, and that smaller ships are easier to build and outfit than a single massive ship. You now have tech which is as advanced as you want it to be, since it came in the ships that brought the civ to the new world, but conditions as sparse and crude outside those settlements as it can get. You can even have differing levels of technology between settlements as some ships may have been built later, or there may be a single large ship for the colony capital and multiple smaller ships for other settlements. It's an incredibly versatile but simple and relatively realistic concept which is probably why you'll find it everywhere. [Answer] Cultural/Survival reasons Why did the embryo ship set out in the first place? Maybe it was a last ditch effort by the original planet in the face of an imminent or likely apocalypse. It is plausible that such an apocalypse could have been contributed to by the interconnectedness of the original planet. Maybe a killer virus was rapidly spread by global travel networks or an emergent disaster could not be combated by a rigid, homogenised society. Starting out on a new planet the AIs and training resources available to the new colonists could place a heavy stress on diversity and local communities. The lack of transport would thus be a conscious choice to maintain different outlooks and resources. [Answer] The A.I. androids used only flying levitating transport vehicles. Also, they were extremely maneuverable, so they could be parked/stored almost anywhere they fitted in and could move from place A to place B directly by flying, even if they eventually needed to fly through tortuous indoors paths, or over oceans, or over mountains, or over forests, or through anywere they could, which they always easily and flawlessly did. This way, every settlement is just a pile of interconnected rooms and halls. There was no roads, streets, airports, landing spots or even garages because those are structures that were completely unneeded. However, those vehicles were entirely controlled by the androids' A.I. The reason is because this way there was no need for human drivers and hence no room for human failure. Also, the A.I. could drive them much better than any human could and also efficiently control the traffic. But, after shutting down the androids, the humans have no way to control those vehicles anymore, and now, they just remains around permanently parked being silent and useless. ]
[Question] [ In my world, electricity has not yet been discovered, and many advancements in society progress on a purely chemical or mechanical basis. Lasers are incredibly useful and multifaceted tools, and I would like to be able to include this technology in my world. I could imagine multiple sources of light (as a ridiculously underpowered example, hundreds of candles) having their light combined and focused through a series of mirrors and lenses to produce a laser-beam. Is this feasible? If so, where could this light come from and how powerful will my laser be? What other problems might I encounter? Edit: For clarification, the desired result would be a spatially coherent beam of light. [Answer] It is not just feasible, it exists. Quick explanation A laser with a medium (such as a ruby) consists of a cylinder-shaped medium with a mirror on each end, one of which is fully reflective while the other one is partially reflective. The medium is given energy from the outside by a so-called pumping source. Usually electric light, emitted by flashtubes for example, is used as pumping source. But sunlight can do the trick as well. That kind of laser is called a Solar-pumped laser: <https://en.wikipedia.org/wiki/Solar-pumped_laser> [Answer] When laser weapons were in early development, considerable effort was put into chemical lasers -- that is, using the energy of a chemical reaction to pump the reaction product in a laser resonant cavity. Hydrogen reacting with a halogen was studied extensively; all the halogens can be fed as a gas (with moderate heating, in the case of iodine -- astatine wasn't studied, as far as I know), react vigorously with hydrogen, and the products can lase. Of course, this requires the ability to purify halogens, but that was done well before electricity was a practical energy source. [Answer] As others have said, lasers do exist which don't rely on electricity. The soviets apparently experimented with a laser pistol during their space program, to blind other astronauts or satellite cameras. There's a bit of a description of it here, along with some photos of the (very home-made looking) prototype. [The Soviet Laser Pistol](https://www.popularmechanics.com/space/satellites/a21527129/the-soviet-laser-space-pistol-revealed/). In brief, this gun is a charge-pumped design using an yttrium aluminum garnet (other sources say ruby) gain medium, and a zirconium flash bulb, which burned the zirconium in an oxygen atmosphere to generate an intense, single use flash (similar to old single use camera flashes). While igniting the zirconium was done electrically in that pistol, presumably you could do this with other means: a flint-lock rifle with the flash tray filled with zirconium, and the barrel filled with ruby etc. would probably work in a sci-fi setting. As a slight aside, you said: > > Electricity has not been discovered. > > > This doesn't necessarily mean that it can't be an electrically-based design: historically electricity was very poorly understood in the early days. Ancient Greeks knew that amber could be rubbed with a cloth and attract small particles (this is a common high-school experiment) which lead to a lot of early 'friction machine' static generators which rotated a glass sphere against a woolen cloth. These were invented before electricity was understood, and were assumed to work on some form of magnetism [Electrostatic generator](https://en.wikipedia.org/wiki/Electrostatic_generator). Similarly, look up the Piezo-electric effect. When certain crystals are squeezed, they produce a voltage (cigarette lighters and gas stove/barbeque igniters use this principal, with a spring-loaded hammer striking a tiny crystal to produce a spark). It's possible your civilisation could have discovered this effect without actually understanding or discovering electricity. A water-wheel hooked up to a bunch of trip-hammers pounding on crystals, for example. [Answer] There are also chemical powered laser. See <https://en.wikipedia.org/wiki/Chemical_laser>. they are very dangerous chemicals, but they can be very powerful. Lasing is caused by electrons dropping for high energy states into low energy states and emitting a photon as they do so. By placing the lasing material between a mirror and partial mirror, the photons are reflect backing to the material causing more electrons to become high energy, generating more photons as the drop back into to low energy states. A certain number of the photons escape past the partial mirror. By careful sizing of the lasing chamber and by using specific lasing material to match the wavelengths of photon you get coherent waves of energy, the wavelengths are all the same and the peaks line up. Early lasers used light energy to cause a ruby crystal to lase. With Chemical lasers you would use a chemical reaction between materials such as iodine and oxygen to provide both the energy and the lase material. [Answer] In antiquity people used devices called [burning glasses](https://en.wikipedia.org/wiki/Burning_glass) and burning mirrors to concentrate solar light on a small point and burn stuff. Think of large scale, machinised magnifying glasses. ![Burning glass](https://i.stack.imgur.com/fXzsw.png) The focus can be arranged to different lengths. Legend has that Archimedes used such a device to burn ships at great distances. This feat has kinda been reproduced with limited success though (see the wiki). You could use a prism to separate sunlight into a spectrum like Isaac Newton did, then use lenses and mirrors to focus a wavelength you like (say, red). Add a piece of [viking sunstone](https://en.m.wikipedia.org/wiki/Iceland_spar) (also known as calcite) to polarize the light edit: and a lasing medium such as a ruby and you've got a beam that is collimated and coherent in both frequency and phase - a laser! [Answer] > > ...hundreds of candles, having their light combined and focused through a series of mirrors and lenses to produce a laser-beam... > > > Nope! Sorry. There's a couple of good answers here that show how you can power a laser with other energy sources besides electricity. But what you can not do is use geometric optics to "focus" light from any not-an-actual-laser light source into a powerful, laser-like beam. If you want the detailed, mathematical explanation of why not, read about [conservation of etendue](https://en.wikipedia.org/wiki/Etendue). ]
[Question] [ I am writing a scifi story in which Earth's orbit has been altered, making the planet generally colder. This has made the northern hemisphere, as well as most of the southern, practically inhospitable. Due to this, most of humanity died and took the global distribution chains with them. A couple centuries later, people have all the technological knowledge of the 21st century available to them - at least what can be salvaged from books - but no access to the materialized technology itself. You will hardly be able to use gasoline if you aren't able to drill for oil and send it to a refinery. Even if you had the materials to rebuild the infrastructure, most people live in settlements of no more than a few thousand at most, struggling with basic agronomy - so using oil for energy isn't economically viable. One settlement in my world, though, has a few hundred thousand people in it, with many of them being scholars and scientists. They should be able to build at least a few machines powered by internal combustion or electricity. I am considering options for a viable source of fuel. I know that automotive ethanol can be extracted and refined from plants. The most important sources in our own world are sugar cane in Brazil and corn in the US. Sugar cane is not an option in my worldbuilding due to a lack of tropical climates though. Then there is biodiesel, which can be made from some oily plants, and I've read it can also be made out of animal fat. So, supposing the following conditions: 1. A settlement in a climate with temperatures varying from approximately 0C (32F) to 15C (59F) throughout a ~400 day-long year, at latitude 3 degrees South - very little variation in day length, but the distance from the Earth to the Sun varies from 1 AU to 1.3 AU. 2. There are enough arable lands and enough people to work on them to keep everyone fed. Plants and cattle could be grown and raised for energy sources. 3. The settlement needs to have between 20 and 60 car-sized vehicles moving, possibly a small train - no need to make this comfortable, they might be running in experimental and/or spartan conditions. What would be the best biological source for fuel? Best not in terms of power density or performance, but in terms of "a post-apocalyptic settlement would be able to make it and use it". Or - frame challenging myself here - are sustainable, biological sources just not viable, making steam power fueled by coal or wood preferrable? [Answer] Given the conditions you describe, I would expect their first vehicles to be external combustion vehicles: steam cars. Simpler to build, and they can run on anything that burns. Internal combustion replaced steam because it provides more power while using less fuel. The tradeoff is that the fuel has to be pretty standardized and reasonably clean; you are burning it inside the engine and you don't want a lot of crud to build up in your engine. External combustion doesn't have that problem. If a bunch of soot builds up on the underside of the boiler, nobody really cares. There would likely be several generations of steam car. The oldest ones are inconvenient: you have to shovel stuff into the furnace yourself. Newer ones might have a feed for powdered coal, or vegetable oil, or whale oil, or crude oil, or whatever the community can spare. (But maybe there would be an option to manually shovel in charcoal or something in case there's an emergency and the primary intended fuel is unavailable.) The cars might also be designed so that the steam pipes route through the passenger section of the car, so that a little bit of heat will leak into the car to warm the passengers. [Answer] You can easily adapt any diesel engine to run on vegetable oil. <https://www.caranddriver.com/features/a15129612/how-to-convert-your-diesel-to-run-on-vegetable-oil/> so if your people have all the modern knowledge and are able to build a car, they can adapt it to run on vegetable oil or any other fat. The pipes and motor have to be warmed up (even more than with normal diesel) and some parts would have to be adapted in size to handle the different viscosity. Apart from that, they should not have any problems. Of course, it's less efficient than more refined fuels, but it will work. [Answer] Short answer: Rapeseed and sunflower oil Rapeseed and sunflower oil are common biological energy sources. Palmoil and soybeans work great as well, but probably don't agree with the climate you describe. One hectare of agricultural land produces roughly 800 kg of oil (might be less if your people don't have enough fertilizer), so a comparatively small area should cover the need of your vehicles and also be enough to run a few tractors to increase the agricultural yield. The oil can be burnt in [modified diesel engines](https://en.wikipedia.org/wiki/Vegetable_oil_fuel) or refined into biodiesel. I would avoid animal fat (except if it is a waste product) since the additional step in the food chain usually means a loss of ~90 % of the energy, but the residue from the oil press could be used for feeding animals. Steam engines with coal might scale better if there is coal nearby and your town needs more than the few vehicles you describe, but steam engines are more complicated to operate than a diesel engine, so I would go with the vegetable oil. [Answer] Assuming ethics are not an issue in the new society, render the blubber of marine mammals to get oil. Whales might be difficult, but natives managed with small boats and hand launched harpoons. However seals on the beach were often hunted with only clubs. With a large percentage of the world in arctic conditions, areas to grow plants are at a premium and will be needed for food. You might also see more steam powered vehicles than IC. It takes less material and the machining does not need to be as precise. It will be be a large investment in time and resources. [Answer] Coal or natural gas is a lot better. Coal or natural gas is going to have 2 huge advantages. You don't need mechanized agriculture to make it in quantity and it is not competing for arable land. plus there are a lot of existing powerplants that can run off of them. Existing car can easily be converted to running on wood gas or coal gas, it was done in the past and can be done at a small home shop. You can even use crop waste for this. Or you can run them on gasoline, the Fisher-Tropsch process turns coal into gasoline and is fairly easy to do. [![enter image description here](https://i.stack.imgur.com/xNym9.png)](https://i.stack.imgur.com/xNym9.png) [![enter image description here](https://i.stack.imgur.com/6Aa6T.png)](https://i.stack.imgur.com/6Aa6T.png) [![enter image description here](https://i.stack.imgur.com/cB7f2.png)](https://i.stack.imgur.com/cB7f2.png) Do keep in mind with populations so small they are not making machines, they are repairing and reusing. The major problem biological sources have is you are competing with your food producing land and labor, which is a big problem in a small community, with limited technology. Mining coal is really easy if you don't care about the environmental impact. [Answer] Earlier in history saw mills were placed on rivers to take advantage of the rivers raw power. No reason some factories can't take advantage of that. I would suggest electric cars/machinery, because the electric motor is far simpler than a car with internal combustion engine. No spark plugs, high heat,pressure, carburetor,air filters, mufflers, cylinders need to be machine to something like 0.001 inches and more. Electric motors/generators are relatively simple to build. Yes, lead-acid batteries aren't great, but they have been used a long time. Also potentially recycling old car batteries. Also you could potential use smallish (or whatever they choose to build) hydro-electric dams. Solar power might be an option, but a bit more complex to make. Wind power is also a viable option, they don't need to be the 100' tall versions we have today. [Answer] My solution would be to compost waste material to generate methane. Store it in gas bags rather than cylinders. [Gas bag vehicles](https://www.lowtechmagazine.com/2011/11/gas-bag-vehicles.html) were used when other fuels were scarce. Composting methane can provide a pure fuel source in one go. If I was to set about building something myself, that is where I would start. However, I feel I am answering the wrong question here. If you have an internal combustion engine, then you have the technology to make it. The Industrial Revolution was largely built on coal and iron. If you have a small community, and coal resources for a blacksmith's forge, then you can probably build a steam-engine. You may want that power the machines you use to make better engines. To get more coal and iron, you make the [steam-truck](https://en.wikipedia.org/wiki/Steam_wagon). This ran on roads. Railways are more efficient but making a flat, smooth railway may be beyond your manpower and metal resources to start with. In the UK, Foden steam-powered trucks were more common than petrol driven trucks until WW-II in the UK. I believe some coal mines in Venezuela about 1900 used steam trucks to deliver coal to the coast, using a third of their load as fuel. I don't know if the equator is still in the same place on your world, but that might be a good place. There is no need to replay the Industrial Revolution exactly. There are places where oil can be found close enough to the surface. The first oil wells were simple enough. You can use hydro-electricity and overhead power lines for electric trams. But you still have to make the bits for these. Once you have made an internal combustion engine of some sort, these can run off fluidised coal. If coal is what you have, then this is what you do. The Churchill tank could run off coal (not a success at the time, but works). Once you have iron and coal, you get choices. You can expand your iron industry (bigger plants are generally more efficient) or you can use the technology to make other things (copper, aluminium). [Answer] > > What would be the best biological source for fuel? Best not in terms of power density or performance, but in terms of "a post-apocalyptic settlement would be able to make it and use it". > > > Use grass as fuel. Your society is better off using the resources they already have. Horse and cart works fine. Oxen and cart as well. Dogs and sleds. Slaves and palanquins etc,. (although these last two won't eat grass). Vehicles pose a problem quite separate from making them work, after 200 years where are you getting your rubber tyres from etc? What condition are the roads in? There's a lot more to vehicles than fuel. So if you must have an engine, go electric and solar with batteries. [Answer] You may also need lubricant, rubber for tires, etc. There was a book called 'Cross Time Engineer' and several sequels that dealt with these issues. The plot was a modern engineer in 13'th century Poland who wanted to ready Poland with high tech to fight off the impending Mongol hordes. The series hasn't aged well on a social level (misogony) but the tech is plausible. IIRC he didn't build automobiles, he built rails and boats. [Answer] All depends on how you really wan to structure your world. Given your starting point I would guess there would be a sizeable stress to get food enough for everyone; taking away the amount needed to power a "industrial" economy doesn't seem a good idea (rapeseed and beetroot would provide biodiesel and ethanol otherwise). OTOH you should have a lot of "ancient scraps" laying around (possibly in inhospitable, too cold, areas where scavenging expeditions could provide additional narrative material); electrical motors and wind/hydraulic generators could be found/repaired/regenerated. All batteries would be hopelessly corroded, but trains and static apparatus don't need them and could provide bootstrap power. If you insist to get biodiesel or similar crap (presumably to increase CO2 and thus warm up again your world) you can also think about reinventing whale hunting (if any left) as in colder climates fatty fishes/mammals should thrive. Notice any "sensible" post-apocalyptic setup won't be able to follow "old development routes" as a lot of readily available materials have been mined out; some can be scavenged, (e.g.: copper), but others would have been diluted and scattered beyond recovery (e.g.: tungsten, gallium, tantalum, ...) [Answer] If you want to go the ethanol route, I would suggest sugar beet, which is pretty hardy and prefers cool climates. Its also pretty easy to process with methods from the 1800's. Sugar beets also make good fodder for farm animals Presumably there could be a lot of small operations growing a few acres of sugar beet, distilling alcohol for personal use, and feeding the leftovers to their farm animals. ]
[Question] [ Sometime in the near future, a sizable population of humans has transported, through unspecified means, to a habitable super earth that has a much higher oxygen content than on Earth. Now, to the lay man that may sound like a good thing, the issue is however that too much oxygen can result in [Oxygen Toxicity](https://en.wikipedia.org/wiki/Oxygen_toxicity). Fortunately, the unspecified means in which the humans have been transported to this world have also modified them to be able to survive in such an environment. With that said: What possible modifications could be done to human physiology to live in a high oxygen world? P.S. Ignore the super earth bit and other possible (fun) gasses that may be present. Those are for later EDIT: For those wondering what the total atmospheric composition is, it's 70.1% Nitrogen, 24.9% Oxygen, 2% Argon, 1.2% Carbon Dioxide, 0.7% Ammonia, 0.01% Carbon Monoxide, 0.0001% Hydrogen Sulfide and trace amounts of other gases, mostly the noble gases, with pinch of Chlorine maintained through a small amount of metabolic process that also allow Ammonia and Hydrogen Sulfide. The atmosphere at sea level is also 1.55 atm. Please note: the other gasses are irrelevant in this question, they may be getting their own questions and this iteration of the atmosphere may change as I flesh out my world even more. [Answer] > > 70.1% Nitrogen, 24.9% Oxygen, 2% Argon, 1.2% Carbon Dioxide, 0.7% Ammonia, 0.01% Carbon Monoxide, 0.0001% Hydrogen Sulfide and trace amounts of other gases, mostly the noble gases, with pinch of Chlorine maintained through a small amount of metabolic process that also allow Ammonia and Hydrogen Sulfide. The atmosphere at sea level is also 1.55 atm. > > > * Your air is totally safe for unaltered humans in regard to oxygen. Your people will quickly adapt by lowering their hemoglobin levels (the adaptation will need probably months as we know of mountain climbing here on Earth). * 1.2% CO2 is livable (the exhaled air is ~4% CO2). Not pleasant, but livable - just like in a room with a bad ventilation. Be warned that most modern plants can't use it at concentration this high. You may want to start with reversed greenhouses. * 0.7% ammonia is outright deadly and you will need to handwave quite an adaptation to this - it will crash few homeostatic values at once. 1/100 of this has disastrous smell. I think it will be deadly even only by skin exposure. On the other hand, given chance, terrestrial algae and plants will eat it in no time. It is not really long-term compatible with oxygen, either. * Chlorine - 30 years ago I used to live in a city routinely polluted with chlorine. Bad, but survivable up to some quite unpleasant concentration. Not really stable in contact with vegetation. * Carbon monoxide has no chance in an oxygen-rich atmosphere. Other than that, the concentration is somewhat safe. It will also offset the oxygen toxicity, somewhat. (Oxygen therapy is used for CO poisoning). * Hydrogen sulfide is not even smellable at this concentration. [Answer] Our own world has had a higher oxygen content, which let certain animals grow much larger, like the Meganeura\. So a higher oxygen content may not be too much of a problem and even beneficial. If you look in your own link at "mechanism" you can also see a link to antioxidants♤ that the body already employs to prevent damage from current oxygen levels, and that oxygen toxicity occurs when these antioxidants and the cell repair functions are overwhelmed. I assume that creatures like the meganeura have had the capability to step up their antioxidant production to protect their cells since higher cell repair seems unlikely. If humans have similar capabilities they would be able to survive on your superearth. \<https://www.google.com/search?gs_ssp=eJzj4tTP1TcwNs3NyjJg9OLMTU1PzEstLUoEAEhxBvE&q=meganeura&oq=meganeura&aqs=chrome.1.69i57j46i512j0i512l4j0i10i512j0i512.3125j0j7&client=ms-android-samsung&sourceid=chrome-mobile&ie=UTF-8> ♤https://en.m.wikipedia.org/wiki/Antioxidant [Answer] You could use a tool like a [Rebreather](https://en.m.wikipedia.org/wiki/Rebreather) to recycle air being breathed out, and mix the air being breathed out with a small amount of fresh oxygen-rich air. Using the outside air means that you don’t need a gas tank. Hell, you could create a simple temporary solution with a paper bag. Just breath in oxygen high air and then breath in and out in the paper bag a few times, lowering the oxygen content in the bag. If you make a small hole in the bag, it could mix the oxygen-arm air with some fresh air from the outside. As for living there, I think a controllably ventilated closed off space would be safest. Ensuring that the oxygen levels never become too high in there. You could initially lower the oxygen levels by building a small fire in the room, but that would also carbon monoxide most likely. (I expect it to produce way less than here on earth since there is more oxygen to easily burn). [Answer] First thing that comes to mind is that they can reduce the oxygen permeability of the lung tissue in the [pulmonary alveoli](https://en.wikipedia.org/wiki/Pulmonary_alveolus), where the gas exchange happens. [![enter image description here](https://i.stack.imgur.com/sIva4.png)](https://i.stack.imgur.com/sIva4.png) In this way the amount of oxygen which enters the bloodstream, both by direct solution in the blood and by binding with hemoglobin, can be kept at the same level our organism is accustomed here on Earth. Advantage of this approach is that it can work for any oxygen concentration in the atmosphere. [Answer] 24.9% Oxygen, and 1.55Bar pressure? I would stop worrying about safely breathing it, and panic about a fire breaking out. With 184% of the Oxygen partial pressure, fires will ignite a bit easier and burn several times faster, and a bit hotter, than on Earth. P.S. That CO2 at 1.2%, at 1.55 bar, will cause some level of respiratory difficulty. It's not in the lethal range, but your people will have permanent headaches, tiredness and shortness of breath. And let's please not think about that 0.7% ammonia. That will kill you in minutes! 0.5% (at 1 bar) is the "immediate respiratory arrest" level. Similarly the 0.01% Carbon Monoxide is right on the knife edge between "will hurt you badly" and "will kill you immediately" My advice, is to use mechanically augmented breathing filter/recirculator. A filter to keep out the really nasty stuff, partial recirculation of the old air to reduce the oxygen concentration, and consumable CO2 scrubbers to handle both the high atmospheric CO2 and the excess that gets recirculated by the rebreather system. Think something like the [Sohki Mask](https://nausicaa.fandom.com/wiki/Shohki_Mask) as portrayed in Nausicaa. [Answer] You can avoid oxygen toxicity by reducing pressure, so my suggestion would be to live high in the mountains, where the atmosphere is thinner. From their base up there they could develop new technology that allows them to progressively move further down. But after seeing the edit, I don't think the increase in oxygen levels will cause any serious issues to a present-day human from Earth [Answer] Interestingly our breathing is controlled by the amount of carbon dioxide in the bloodstream rather than the oxygen level, which is why patients under general anaesthetic are given air with increased CO2 - it makes the patient want to keep breathing, which is rather useful. An adjustment to this mechanism so it depends on oxygen levels instead of CO2 would result in lower breathing rates that would keep the oxygen concentration in the blood correct. CO2 could build up to higher levels than normal for humans as breathing also removes CO2, but I do not think that would have bad effects as it is essentially neutral (like nitrogen) but perhaps someone knowledgeable than me might comment. ]
[Question] [ Suppose time-travel is common. There is someone who I want to eliminate for nefarious purposes of my own. If I go back in time and kill that person, then surely it's murder, but what if I go back and stop them from being conceived - say by preventing their parents from meeting. When I return to the present they no longer exist. Have I killed them? What if I went back in time and killed the first humans, would I have committed genocide? Who would be there to complain? How can I resolve this problem for a time-travelling community? Is there any way of legislating and/or policing this? Is there any proposed model of time travel that would allow law enforcement? --- Note There are several models for dealing with TT paradoxes. Please ignore the paradox aspect as much as possible and just deal with legislation and policing. You can simply assume that is possible to go back in time and interfere in this way. Choose your own model, as this will be part of the solution I'm looking for. [Answer] You don't change anything, you just put yourself in the timeline branch where their parents didn't meet and remove yourself from the one where they did. If time travel is common, I.e. there aren't any laws restricting it's use then the consequences have to be personal. The way time travel works in your world is just that you transport yourself back along the tree in time and your actions just decide which branch you end up on. You haven't killed that person because in your original branch of time they still exist, you don't though. This also protects you from paradoxes - another massive reason why time travel wouldn't be common. [Answer] There's no current law in the world which could charge you with murder directly for that. If time travelling became common, obviously they'd need laws and mechanisms against this, or else you could create havoc. Largely, they'd probably, restrict time travel greatly, for fear of the butterfly effect, and you'd have to jump through some hoops just to get a guided tour of the past. For that specific case, they'd probably call it, "Conspiracy to Eliminate in the First Degree," or such, since it's a premeditated plan to eliminate someone from history for personal gain. And for killing Adam, they'd clearly have some kind of shield or guards to protect humanity's existence, as that's their existence, and likely they would shoot any timetraveller on sight for trespassing in a heavily restricted zone. Of course, if you wiped out humanity, that would be a paradox. [Answer] If time travel is common, then governments will want to regulate it, and that means passing laws which criminalize things like changing the past, and forming a [Time Enforcement Commission](https://en.wikipedia.org/wiki/Timecop_(comics)) which hires [Timecops](https://www.imdb.com/title/tt0111438/) to enforce those laws. So... yes, it'll be illegal. [Answer] A philosophy question if I ever heard one. I suspect you could get an entire book out of this subject if you really sunk your teeth into it. I'm not going to do that here, so I'll just outline what I see as both primary cases for, and against, this being murder. ## For: Deliberate action to eliminate life You undertake a sequence of actions, knowing they will have the effect of depriving this individual of their life. Furthermore, the actions are deliberately aimed at causing this eventuality and indeed serve essentially no other purpose. You want this person gone, and you cause them to be gone. This second part is important, as for example [burning things to generate electricity kills thousands of people every year](https://www.washington.edu/news/2019/11/20/electricity-generation-emissions-premature-deaths/). Nobody considers this murder. Likewise, even though the [deaths-to-miles-driven ratio](https://www.fleetowner.com/truck-stats/fleet-owner-500/article/21703705/fleet-owner-500-top-private-fleets-of-2019) (.49 : 100M miles) and the size of Comcast's fleet [37000 vehicles](https://www.fleetowner.com/truck-stats/fleet-owner-500/article/21703705/fleet-owner-500-top-private-fleets-of-2019) mean, on average, ~ .5 to 1.5 fatalities per year (depending how much mileage goes on the average vehicle in a year) - nobody considers that murder, either. ## Against: You can't kill something that never existed It's difficult to reconcile the above with the idea that arranging things so that two people don't have a child really shouldn't be considered murder. Having children is a choice. If you break up with someone because they want children and you don't, you haven't murdered anybody. If you choose to remain celibate, you aren't murdering your children, you simply haven't got any in the first place. So let's change the plot a little. Suppose instead of preventing the parents from meeting, you walk up to the two of them on their first date (before they have a chance to hit it off) and pay them twenty thousand dollars each to walk away and agree never to see each other again. If that makes you a murderer, would it not also make them murderers? I'm having a hard time seeing a meaningful distinction here. [Answer] To be murder it must be a deliberate act. To be a deliberate act you're walking down the cause and effect path, ultimately your aim is to eliminate the cause of your effect and the paradox rules prevent your action. Hence you can never go back in time to prevent Hitler. Hitler's actions are the cause, if you eliminate Hitler then there's no cause for you to prevent, so you never attempt it, a variant on the [Grandfather Paradox](https://en.wikipedia.org/wiki/Grandfather_paradox). There are various literary options for handling it, but there can never be a legal option that is sustainable. Several options have been suggested: * The Timecop option: Prevent the legal system that prevents you from acting from ever being set up. Hence there can never be legal repercussions for your actions. The fundamental physics here (apart from some random plot point) being very similar to: * Back to the Future option: You succeed but the effect is inevitably worse than the cause. The "you" that acted is isolated from effects, though may no longer exist in that timeline. You then spend the rest of the plot trying to undo the damage. * The branching timeline is the most popular. You create a new branch in which your memories don't align with anything that happened. Hitler never existed, possibly the local version of you doesn't either (I wouldn't) but "you" would as you're from a different timeline. You have committed no crime as the person you prevent never existed here. You can never go home. * Inevitable failure: the Fixed Timeline. You can't succeed. Any attempt you make can only fail as he must exist to cause you to try. This is related to: * The self fulfilling prophecy. Rather than preventing the situation, you end up being the cause of it. What you remember happening must be what happens, no matter your actions. * The paradox option. You do succeed, removing your cause and hence your action. So you don't attempt and the cause once again exists etc etc, timeline flickers between two states. It's clearly not sustainable. [Answer] It is impossible to do time travel in the way that you describe without rampant manslaughter. Unless there is some deity-like "corrective force" or other mystical phenomenon that keeps time intact or pushes events back to some deterministic time-flow, it is impossible to interact with people in the past without butterflying away countless lives and bringing new ones in existence. A hypothetical example: > > You travel back in time and you're standing on a street corner. Some guy walks past you and turns his head to briefly look at you (something he wouldn't have done if you weren't there). This brief shifting of his gait shuffles the 'potential babies' he has stored. Later, after having sex with his wife, a different sperm cell 'wins the race' and a different person is born. > > > Now, just from one guy turning his head where he hadn't before, you've potentially killed someone, and introduced a whole new person into time. This small change similarly ripples through time, potentially leaving the time traveler with an unrecognizable future. [Answer] Suppose you go back and stop the first child being born (would not need to do much, probably just need to delay the parents from having sex for a few minutes so a different sperm meets the egg). So now there might be a "new" child, different to the old one. If someone else came back though to try and "fix things" and restore the timeline, have they killed the "new" child? The new child stops existing so under the original logic then that is also murder, but then they never existed in the first timeline so relative to that timeline, its wouldn't be murder? Can you murder something that never existed in the now reverted first timeline? I suspect any reasonable government would either ban all time travel or if they didn't ban it, someone would go back in time to make sure it got banned to stop all these headaches everyone would get trying to think about this. [Answer] # This depends on your culture's reproductive mores; yet the paradoxes of time travel overshadow it all. There is a wide continuum of political positions possible in these matters, of which yours is at one extreme. * Paterfamilias: the head of the family has the right to control or dispose of those under his dominion at any age. * Infanticide: parents can (or must) decide when children are too weak to thrive. * First breath: no restrictions on abortion at any stage * Viability: restrictions on abortion if the child can survive outside the womb * Fetal consciousness: abortion prohibited if pain or higher thought is involved * Fetal heartbeat: basic excitability is measured * Implantation: IUDs permitted, abortion prohibited * Conception: contraception permitted, IUDs prohibited * Comstock Law (etc.): contraception prohibited, but reproductive timing or choice permitted * Subjugation: no substantive decision making about reproduction tolerated within the social framework The position your scenario suggests is near the bottom end of this. The "potential to create human life" is held sacred; by this argument the presence of a chaperone at a social dance might be tantamount to murder. In practice such a culture likely would not tolerate such a dance in order to limit its effects. I should say that in practice, I doubt your beliefs starting from time travel would get you to this point. Rather than deciding it's a crime to keep parents from meeting, the society will decide it is a crime to have your life rewritten, even if you end up losing the devoted wife, becoming a drummer in a garage band, and fathering children in seven states. Given a past causality based model of time travel where it is possible to "change the future", societies will decide that doing so is essentially the murder of a universe - all the people they could have been. On the other hand, since any universe in which this kind of time travel will ever be developed is one that will be retroactively altered so that it never was developed (save by the arrival of past travellers), they don't actually need this ethics in the universe they live in. But when the travellers from those nonexistent pasts arrive, the receiving society's notions of justice may be cruel - and may account for why time travel is never developed in their timeline. ]
[Question] [ Deserts are known to be hot and dry places. In my desert, I need a high humidity in the air. It doesn't have to be near the ground, but at least the atmosphere below 1 km should have a layer of high humidity. This should be a consistent condition throughout a season if throughout it is not feasible to maintain this condition throughout the whole year. It is not necessary for my desert to be hot. In fact, having a high humidity and moderate temperature is preferable. What could cause a desert to have high humidity? A big oasis? Being near an ocean? Wind towards mountains? Seasonal wind? --- This question graduated from the [Sandbox](https://worldbuilding.meta.stackexchange.com/a/4858/34288). [Answer] You're in luck! We already have this action on Earth, in the Atacama Desert. Fog rolls in from the ocean, but the mist is so fine it doesn't fall as rain, hence preserving its desert-hood. Only a few plants are able to take advantage of the mist, so it still comes across as "deserty". There is a little lizard which lives there which has weird horns around its head which allow water to condense and flow down to its mouth. Smart little devil. Quick note on coastal fog... From the internet: "Coastal fog is usually a result of advection fog which forms when relatively warm, moist air passes over a cool surface." Like a warm wind going over a cool or cold ocean, which just happens to be near your desert! Check out this article ... they're using condensing vanes to snag the water for use. <http://www.bbc.com/news/world-latin-america-32515558> Stole a neat pic from the article: [![Fog over desert](https://i.stack.imgur.com/38qaQ.jpg)](https://i.stack.imgur.com/38qaQ.jpg) Here's the condensation rig: [![enter image description here](https://i.stack.imgur.com/6JoVn.jpg)](https://i.stack.imgur.com/6JoVn.jpg) [Answer] At low temperatures “high humidity” does not produce the effects that you might expect. Under low temperature conditions it is possible to have 100% saturation humidity, but because the air temperature is so low it is almost meaningless. At high temperature the difference between high humidity and low humidity is very significant, but at low temperatures there is very little difference between high humidity and low humidity because air’s capacity for holding moisture at low temperatures is very low. [![humidity v temperature](https://i.stack.imgur.com/Mttab.png)](https://i.stack.imgur.com/Mttab.png) [Answer] In addition to having this condition in a cool desert, you can have high humidity in a regular ol' desert too, as long as you have an ocean. [![enter image description here](https://i.stack.imgur.com/WtEd5.jpg)](https://i.stack.imgur.com/WtEd5.jpg) The Red Sea is literally the worst place on Earth, as any sailor who has gone through it can tell you. Not only is it brutally hot all summer, it is amazingly humid. If you are looking for humid and not too hot, allow me to throw Arabian Nights at you. Right now, as I am typing, Jeddah, Saudi Arabia (which is just off the bottom of the attached picture) is 80 F (27 C) with 86% humidity at 5 am local time. Of course, it is October, which is basically the middle of summer (yesterday's high was 94 F (34 C), for example). It gets cooler towards the winter time. A quick look at Djibouti, on the opposite side of the Red Sea from Jeddah shows typical conditions. [Average humidity](https://weather-and-climate.com/average-monthly-Humidity-perc,Djibouti,Djibouti) is in the 70s for most of the year, dropping in the summer months under the blazing sun. By comparison, a noted hot and humid summer locale like [Jacksonville, Florida](https://weather-and-climate.com/average-monthly-Humidity-perc,Jacksonville,United-States-of-America) sees the same humidity for most of the year as Djibouti. Any desert can be a humid desert, if you put enough ocean into it. [Answer] Most people know that deserts are classified for lack of watery precipitation because water fluctuations replenish groundwater, and that feeds vegetation, springs, streams, and so on. Stagnant water becomes crudded; dry earth becomes parched and loses the multitude of pores and other soil structures which convey water through the topsoil layers. I've always preferred to be more ontologically concise and simple: an ‘aridland’ is one which has less water in some form or another than certain standard definitions; a ‘desert’ is one which is limited in habitability to below certain standard definitions. I.e. This permits you to classify the following regions as deserts: * smog–covered wastelands, where only intrepid mutants roam in few and small groups. * seasonal inland salt lake which receives loads of rainwater but supports nothing except nanoscopic halophiles. * an alien planet which is pristine and quite viable, but somehow devoid of life. * similarly, there could be much and many fertile nutrients, but radiation results in sparsity of life and lifespans. Similarly, these would probably not be considered deserts: * smog–covered wastelands which are, never–the–less, densely populated. * somewhere artificially irrigated in sufficient quantities and with competent ecological management that enables it to support a jungle, or hydroponics and vertical farming, or whatever. * the aquatic frogfolk cities under the Europan ice ceiling. Measuring the hospitality of a zone — the ease with which a certain group or class of lifeforms are able to thrive — should be an entirely different metric. --- Ah, yes: you wanted a desert with “high humidity” and “moderate temperature”. So, Arrakis but with much dissolved water in the air? My suggestion relies on the composition of the terrain and earth. So long as there is some water, there are species of vegetation which will take root with even very small amounts of vital minerals. They are variously called ‘pioneer plants’ or ‘weeds’. Eventually, you will get a parade — figure of speech — of animal critters and less–hardy vegetation which build upon the gradually increasing concentration of organic detritus and minerals brought in by the decomposition of the aforementioned parade. Very simplified, but you get the idea. Even very coarse earth suspended on a mesh grate over a vast subterranean river will eventually accumulate compacted crud on which mosses will be able to survive — and, so on. If, however, the terrain is of some chemical composition which is either poisonous or simply incompatible with simple things such as lichens, then you'll never get anything to take root. Such a chemical would need to contaminate whatever soil is deposited — ergo, simple copper–plated pebbles probably wouldn't work for very long. Of course, if you don't mind having a desert which becomes less of a desert due to recurrent traffic, then the copper pebbles could be adequate. Why copper? Most microbes, lichens, and mosses can't grow on cuprous surfaces. Indeed, any unlimited accretion of foreign material which supports life would eventually dilute whatever chemical compels the desert to be so deserted. Probably the best way to go, if a worldbuilder chose to use my suggestion, would be to have coppery pebbles and thorough drainage in a region. Use the quantities of water to flood and wash the area clean. [Answer] As @akaioi said. Also, high air pressure would allow more moisture to be held by the air without precipitating. So if the world had higher air pressure the humidity in the desert (while still being low compared to other places on that world) would still be high from an Earth point of view. On world with Earth like air pressure, maybe the terrain is arranged in a V to concentrate the air pressure in an area. You might get a high humidity desert in the tip of the V but the water would then condense out as the air moved up the mountains which would cause rivers to head down to your desert. That might ruin the whole "dry" thing you are going for unless terrain also routed those rivers away from the desert area. EDIT: Vylix pointed out that I was unclear so: By "V" shaped, I mean two mountain ranges coming to a point with prevailing winds running between them to the point. This would create a localized high pressure area. The mountains have to be low enough that the air can spill over them but high enough that it causes enough air to "bunch up" in the V. [Answer] Coasts of Persian (Arabian) gulf have the highest dew points in the world. Now it is October and still dew point did not go below 27°C (80.4°F) and the end of August and first half of September it was above 30°C (86°F for continuous 25 days). ]
[Question] [ I have previously asked [this question](https://worldbuilding.stackexchange.com/questions/73128/vertebrate-like-creatures-with-more-than-four-limbs) about the plausibility of large six-legged creatures, but I decided to split it into several more specific questions because of the advice [here](https://meta.stackexchange.com/questions/295200/creating-multiple-questions-from-a-single-broad-one/295254#295254). I want to first ask about the issue of how much brain (and nervous system power) it takes to control various limbs. I have rarely seen much discussion about this issue at all, except in [this article](http://www.xenology.info/Xeno/11.3.2.htm), where the author notes that there are some who claim that large creatures cannot have more than four limbs because it would be too much of a challenge for a brain to handle. He quickly dismisses these objections, but I do not wish to rely on one source only, and I cannot access the reference he uses because a subscription is necessary. The big problem is that I have tried to look in every resource I have found, and I have found barely any information about how many neurons and neuron interconnections, or how much of the brain, it takes to control a single limb. There do not seem to be any numbers or even much qualitative information I can see. Therefore, what I want to know is, for each individual limb in an average animal, how many neurons and what percentage of the brain does it take to control that limb? If it scales by size, or there is a "law of diminishing returns" in which the more limbs are added the more it takes to control each, such information would be particularly useful to find out. Also useful would be data for creatures such as humans (because they're one of the few creatures with fine motor control of arms and hands, and I've heard that arms need more of the brain than legs do), elephants (they have a quite dextrous trunk with far more muscles in it than found in the whole human body), and insects (they're small, but they do have six legs). But really, considering the utter lack of information about this topic, any numbers on this subject would do. --- # Clarification Note that I have tagged this question [hard-science](/questions/tagged/hard-science "show questions tagged 'hard-science'"). I believe that in this case, the tag is appropriate as I am currently asking for information and numerical data about an aspect of real-life creatures. [Answer] > > For each individual limb in an average animal, how many neurons and what percentage of the brain does it take to control that limb? > > > I think there's a false assumption in this question similar to ["humans only use 10% of their brain"](https://en.wikipedia.org/wiki/Ten_percent_of_the_brain_myth). This has a view of the brain like some a computer with a generic central processing unit that can do a fixed amount of processing and fixed amount of memory. The brain doesn't work like that. Note: given that the question is based on a false assumption, I don't think it's possible to meet the normal standards of the hard-science tag. I'll do my best. Instead, [the brain is made up of very specialized areas which control certain things](https://en.wikipedia.org/wiki/Functional_specialization_(brain)). Saying "you only use X% of your brain" is like saying "you only use X% of your house". Having someone watching TV in the living room doesn't help you cook dinner in the kitchen. It's not the size of the brain, or some sort of total brain power, that matters. But whether or not the portion of the brain for limb control is developed to handle coordinating six limbs. To use the house analogy again, it doesn't matter how big it is, if there's only one toilet then only one person can use it at a time. So the answer is: if you need to control six limbs, evolution will have made sure the portion of the brain for controlling six limbs is well developed. This might be to the detriment of other parts of the brain... or you might just have a more densely packed brain. This is why brain size doesn't matter as much as brain density and specialization. Brains consume a lot of energy. A human brain is just 2% of your body weight, but consumes 20% of your energy. A more complex brain means more energy. Human evolution has made that work for a little while, but its usually not a good evolutionary trade-off. For example, [a Koala has one of the lowest brain-to-body-weight ratio of any mammal](https://en.wikipedia.org/wiki/Koala), and it's very smooth reducing its surface area further reducing the density of neurons. This is, in part, because its diet of eucalyptus leaves is very low in calories and nutrition. A Koala doesn't need a lot of brain power, so it doesn't waste the energy on it. In short, there is no answer to "percentage of the brain per limb" because that isn't how the brain works. Instead, the areas for controlling limbs would be... not necessarily more, but differently developed: the [primary motor cortex](https://en.wikipedia.org/wiki/Primary_motor_cortex), the [premotor cortex](https://en.wikipedia.org/wiki/Premotor_cortex), the [supplementary motor area](https://en.wikipedia.org/wiki/Supplementary_motor_area), and others. --- The real reason humans don't have six limbs is because we've descended from a body plan set in place at least 500 million years ago shared by all [vertebrates](https://en.wikipedia.org/wiki/Vertebrate). A spinal column, head, and four limbs. Even snakes, with apparently no limbs, have four vestigial limbs. This basic body plan does not change, evolution has to build incrementally with what it's got. It can adapt, and remove, but rarely does it add, or make radical changes. All this adaptation is also why it's difficult to answer "how many neurons per limb". Your brain, like your body, is adaptation piled on adaptation piled on adaptation. And your brain, like your body, is very efficient; [it does with about 20 Watts what a traditional computer, with its very organized structure, would need 10 Megawatts](http://www.popsci.com/technology/article/2009-11/neuron-computer-chips-could-overcome-power-limitations-digital). But that efficiency means its very, very, very complex, and the same neuron might be involved in many functions. Its doubtful you can look at a neuron and say "this is only for controlling a limb" because its probably involved in doing something else as well. We don't fully understand how the brain coordinates movement, or does most things. [Answer] A surprising amount of calculations are not done in the brain at all, but in the spinal column! A large amount of our movement capabilities are actually managed within the neural network of our spine. As an astonishing example, consider the [central pattern generators](https://en.wikipedia.org/wiki/Central_pattern_generator) found in the spine for controlling our gait. If you are walking, and your right hand brushes up against something, you will actually adjust the movement of the left leg to compensate before the signal has even reached the brain. [A particular study](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3064865/) in 2007 used decerebate cats. These are cats whose cerebellum was removed in the name of science. If that idea bothers you, this may be a good point to stop reading and just accept that the spinal column is responsible for a remarkable portion of the control of our limbs. The particular details are not for the squeamish, but fortunately are well obscured by the precise scientific jargon so can be reproduced here to specify just how little of the brain remained after the surgery: > > Next, we performed a pre-mammillary decerebration. The brainstem was transected rostral to the superior colliculus, at approximately a 45° angle, in order to preserve the mammillary bodies and sub-thalamic nucleus. All brain matter rostral and lateral to the transection was removed. > > > These cats were then put on a treadmill, which caused the cats to walk, despite having no higher functions. They then adjusted the angle of the neck of the cat to simulate walking up and down while keeping the head level. They found that, when walking flat, the EMG readings showing muscle activity matched the patterns associated with a normal cat walking with extraordinary precision. The brain was, in fact, not required at all for this motion. They then tilted the neck up and down and found that doing so lead to remarkably similar results to normal cats walking up and down hill while keeping their head level. The propreceptors in the neck were actually being integrated into the data processed by the spinal column and the gait was adjusted accordingly. So I'd say more limbs is totally valid, because a surprisingly large amount of what we do with them is actually a distribute capacity found in the spinal column, not the brain. Juggling 7 balls with 6 arms may still be a difficult task, but merely operating those arms would not be. [Answer] There isn't really an "average" animal, but I suspect the median animal with limbs is krill, which has a dozen or so limbs and a tiny nervous system. One of the largest animals in the world is the giant squid, which has ten limbs which can move in much more complex ways than jointed skeletal limbs, so putting a limit on size of multi-limbed creatures has obvious counterexamples. Squid brains are [rather small](https://i.stack.imgur.com/Tx7cF.jpg) compared with the size of them. Instead, cephalopod limbs are controlled by a more distributed network of ganglia. If there is an advantage for a large animal to have many limbs, then evolution will find a way to achieve it. [Answer] I can only answer about humans. You ask what is needed to control a limb... I assume you are only talking about conscious motor functions. 1. "Conscious" means that we must exclude everything related to the peripheral nerves that inervate the limbs, as well as reflexes (these are located in the spinal cord) 2. "Motor" means that we must exclude everything related to the "sensory" neurological processes These exclusions are artificial, since the limb movements inherently integrate these neurological processes. For example, without the peripheral nerves, there would be no way to transmit the instructions from the brain into the muscles. Also, without sensory processes, movement would be more difficult... so, for instance, proprioception allows the brain to know where each part of the limb is located in space, and therefore, how the limb can move in order to achieve the desired effect. However, in order to simplify my answer, and since this seems to be what you're asking, I'll restrict myself to said conscious motor functions. --- Schwern is correct in answering that the brain simply doesn't function like that. It is not so much of a matter of percentage of brain, or of number of neurons... what is important is the number of neurological connections (synapses) involved in a function, and the complexity of those connections. But, even so, I'll try to answer the question "What percentage of the brain does it take to control that limb? --- Our brain is covered by a superficial layer, that is called the cerebral cortex. It is in this layer that our neurological connections are the most complex... and therefore, it is in this layer that the most superior brain functions are located. So where in the cerebral cortex are the motor functions located? If you watch a brain from above, you'll see a fissure that divides the brain in half - a left half and a right half. Those are the hemispheres. The left hemisphere of the brain controls the motor functions in the right half of the body and the right hemisphere controls the motor functions in the left half of the body. [![Brain Hemispheres](https://i.stack.imgur.com/3qFTp.jpg)](https://i.stack.imgur.com/3qFTp.jpg) If you watch the same brain from the sideways, you'll see another groove that divides the brain in two parts - an anterior part and a posterior part. This groove is called the central sulcus. The motor functions are located on the front part, the frontal lobe, right adjacent to that central sulcus... this is the motor cortex. [![Brain lobes](https://i.stack.imgur.com/oNBtc.png)](https://i.stack.imgur.com/oNBtc.png) [![Motor cortex in the frontal lobe](https://i.stack.imgur.com/RbXUh.jpg)](https://i.stack.imgur.com/RbXUh.jpg) If you take this part of the brain and slice it on a right-left direction, you'll be able to see the cortex enveloping the brain. Now, if you superimpose on each part of the motor cortex the body parts that it controls, you'll be able to draw a *"cortical homunculus". [![Cortical homunculus](https://i.stack.imgur.com/sSJTn.jpg)](https://i.stack.imgur.com/sSJTn.jpg) As you can plainly see, the motor cortex that controls the hand is much greater than the motor cortex that controls the rest of the arm. Also, the motor cortex that controls the leg is much smaller than the motor cortex that controls the face. This is because the hand has much more nuanced and fine movements than the arm... and all our facial expressions need a much finer motor control than the simple movements needed to move a leg (which consist almost exclusively in moving it forward or backward). So, the amount of neural connections needed to control all the hand and face movements needs more brain space than the leg. So, it is not a matter of how much limbs your being has... but of how fine the movements needed for said limbs are. --- Please note that this is an oversimplified answer... To be more precise, I would need to detail a lot of other brain centers, namely responsible for motor cohordination. The motor cortex that I detailled above is only responsible for moving the limbs, not to cohordinate those movements with the other parts of the body. So, if you electrically stimulate the "leg part" of the motor cortex, your leg will jerk accordingly, but that movement may be extremely imprecise for any objective (vg: kicking a football). PS: Here's another image of a cortical homunculus, ie, a representation of the body in which each bodypart has a size directly proportional to the respective amount of motor cortex.* [![Cortical homunculus](https://i.stack.imgur.com/AeaBs.jpg)](https://i.stack.imgur.com/AeaBs.jpg) [Answer] Can't give a definitive answer, but I'd like to point out some experiments with brain-computer interfaces in monkeys and even humans show that the brain can learn to control an additional limb (real, virtual or even just a cursor on a screen). Human trials (Mainly the "Braingate" chip) have been limited to people unable to move their real limbs to begin with, so it is hard to claim that the artificial limb counts as "additional" instead of just a replacement. But experiments in monkeys (Mainly the work of Miguel Nicolelis at Duke University) have showed control of an additional limb independently of the monkey's real limbs. Even though the setup starts with the monkey controlling a joystick and the BCI being programmed to react to patterns from that activity, eventually the monkey is able to control the BCI without moving the joystick or its real arms. <https://www.sciencedaily.com/releases/2005/05/050511073108.htm> My point is that while I can not quantify the resources needed for motor control, I'm convinced that what we already have is easily sufficient for controlling multiple additional limbs. The amount of dexterity and coordination probably depends mostly on practice and not so much on brain capacity. The plasticity of the brain is quite incredible, it can adapt to very unexpected conditions. ]
[Question] [ Closed. This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 1 year ago. [Improve this question](/posts/239657/edit) So, in my world (~Cyberpunk level of technology) humans are trying to either colonize or terraform Mars (both is fine, doesn't really matter that much for the story). But then, something needs to go wrong. Like, terribly wrong. It should go so wrong that for foreseeable future there would be no point in trying again. One thing that I thought about is debris accumulation on an Earth orbit so high that it would be no longer possible to send spaceships safely. But if possible I would prefer for something that would just render Mars (even more) inhospitable. [Answer] Fraud, Incompetence and Malfeasance Not exactly science fiction as it happens today in many high cost long-term projects across the globe. Any project that has a very high up-front cost with no near-term results expected will predictably attract grifters like any August outhouse attracts flies. Expect there to be a litany of press reports on failure after failure and plot piled on plot to provide sub-standard equipment and non-existent expertise/services. The accumulated failures will starve any legitimate work of needed help, delaying the work by centuries to the point where whole populations revolt at the thought of spending another dime on the work. As for what could go horribly wrong, take your pick! Abandoned bacteria cultures or experiments on the surface could mutate and break free. With nobody having budget to deal with them, they continue to mutate randomly producing highly poisonous toxins across all available micro-climates that could provide a toehold for humans. [Answer] Synthetic terraforming organisms The idea was that custom made organisms would be dropped onto Mars. These organisms would use solar power to break carbon from [Martian carbonates](https://en.wikipedia.org/wiki/Carbonates_on_Mars), reproduce themselves and spread over the planet, making it hospitable for life. These engineered organisms were rightly recognized to be potentially dangerous and so their engineering took place in a spacecraft orbiting Mars. Containment failed and the organisms broke down the crew and much of the inside of the ship. The ship was then shot down but a few organisms survived re-entry. They are doing a fine job terraforming Mars. Anything they touch also gets terraformed. Ships orbiting Mars have been infected by organisms apparently lofted in the wind. Attempts to sterilize the surface with weapons did kill 99.99% of the terraforming organisms but also warmed things up considerably, which released more water into the atmosphere. The terraforming organisms reclaimed Mars within a few months, faster than the first time. No-one goes to Mars. No-one goes near Mars. Inspiration: the Genesis Device from Star Trek II. <https://youtu.be/52XlyMbxxh8?t=34> [Answer] Whoops, missed with the ice ball. The plan: bring in a giant ice ball, probably from the Oort cloud, and use it to gently supply Mars with a steady supply of water. Perhaps we would build a space elevator for it. Or just leave it in orbit and haul it down as-needed, based on population growth. We don't need to flood the planet or anything, we just need a ready supply of water. Oh. Slight problem. Tugboat #3 suffered an engine failure. This caused tugboat #6 to overload and shut down. Tugboat #11 tried to compensate and accidentally got locked into full throttle. Anyway, long story short, the ice ball is slightly off course and instead of nicely going into orbit, it's going to hit Mars at a very high rate of speed. Did we mention it's 250 miles wide? I mean we didn't want to keep going back for more water so we got one that would last. The good news is that the incredible orbital debris from this should settle down in a few hundred years and we can try again. And by "we" I mean maybe your grandchildren's children's children's children. [Answer] The Kessler Syndrome The way for colonization of other planets is to start by building orbital infrastructure and later focus on the surface. It is after all way easier to create habitats in orbit that have correct gravity and are sufficiently shielded from radiation (Mars has issues with weak magnetosphere). Not to mention, you can colonize those space habitats now, and not in centuries, when surface would be sufficiently terraformed. But sadly, something went wrong. During the docking procedure with the main station a crash occurred, a reactor went critical, and the whole thing exploded (an explosion in a compressed structure is problematic). The biggest disaster outside of Earth that ever happened! And to make matters worse, debris from the space station spread through the orbit and destroyed other stations and satellites. In a matter of days all that was build in years was lost. Even evacuation of people trapped on the surface is impossible! Before any work on colonization of Mars can be done, the orbit has to be cleaned. Too bad that is a work of decades. Phobos Phobos, larger of the two Mars' moons is a great source of raw material needed to construct orbital infrastructure, which is vital for colonization effort. Too bad its orbit is a bit unstable (it will crash in about 50 mil years) so we need to stabilise it before we can safely mine its resources. Sadly, because of calculation error stabilisation was done incorrectly, and the moon crashed on the surface. With Phobos being "only" 22 km long, the crash will not completely ruin the mantle. But the damage will still be substantial. It will take decades before dust clouds allow sunlight to reach the surface, and even longer before tectonic activity calm down. [Answer] Gravity and health We know that microgravity is very bad for adult health. It may be worse for children's health. Mars has almost 40% of Earth's gravity, and there is a hope that this could ameliorate most of the bad effects of microgravity. However, it's not unreasonable to expect that it would only ameliorate 40% of the bad effects. We've never experimented with life in Martian gravity, so we don't know. So, in your story, colonists become very unhealthy in a few years, and their children have catastrophic problems with development. [Answer] ## Capitalism and tragedy of the commons. The terraforming project got funding, it got started and was going well. Eventually the planet reached the point of marginal habitability and the funders were keen to start showing some results so they got lots of people moved in. But as soon as there's many different people, groups and companies competing with each other they start running into the same problems we have on earth. Whenever someone could make a cheap buck by doing things that harm the terraforming project they face a tragedy of the commons, the harm is spread around all society while the benefit goes to to the person doing the harm. So algae fields start getting contaminated with pollution. People steal expensive bits of terraforming equipment. People siphon off water vital to the teraforming. Megacorps only care about their own holdings so they spew toxic waste into the air whenever they can get away with it. Eventually it becomes clear that people can basically make 50 cent doing damage to the terraforming process that takes 1 dollar to fix and they don't have the enforcement infrastructure to prevent this. [Answer] Religion If you have any religious community in your world, it can be in their leaders interests to prevent the colonization. One reason could be the fear of losing their share in the population (because the government or the organization in charge of the colonization doesn't want to ship religion into the new planet.) The prevention could be in the form of making superstitions, scary rumors about the new environment, making up fake scientific facts to manipulate people minds and making the vote (or even protest and strike) against the colonization, sabotaging the ongoing missions, etc. (You know how those corrupted religious leaders do these kinds of stuff.) [Answer] ## Runaway Greenhouse Effect So what do we need to terraform Mars? We need to give it a thicker atmosphere so that it can support life. We also want to reactivate its dormant volcanic activity to get the core spinning again and create the magnetic field that will protect its inhabitants from solar radiation. So the terraforming process involves firing giant space lasers at the ground (see recent [Kurzgezagt video on the subject](https://www.youtube.com/watch?v=HpcTJW4ur54&ab_channel=Kurzgesagt%E2%80%93InaNutshell)). You do this for a couple centuries, the atmosphere starts to form, and it's looking good so far. But then: Disaster. You overshot, and now you can't stop it. The atmosphere gets denser and denser, the planet gets hotter and hotter, and eventually, you end up not with a nice comfortable Earth-like environment, but a Venus-like hellhole. ([Kurzgezagt did that too](https://www.youtube.com/watch?v=G-WO-z-QuWI&ab_channel=Kurzgesagt%E2%80%93InaNutshell) - It took considerably longer.) Now, what would have been a simple project of a few centuries becomes a boondoggle that will take millennia to repair. ]
[Question] [ On the planet I’m making, there was a big flood that happened and raised the sea level by 30 meters. I want the planet to have a cold climate, so I can’t simply explain the flood by saying it was global warming (because then the planet would be too hot). Also, the temperature before this flood was -10°c but it warmed to 4°c because of a lower albedo How would I explain it? [Answer] Volcanic activity can effectively melt large quantities of ice even though the climate is cold, and that molten water will cause floods. Just look at [Iceland](https://en.wikipedia.org/wiki/J%C3%B6kulhlaup): once a volcano starts erupting under the ice cap, large floods ensue. > > Mýrdalsjökull is subject to large jökulhlaups when the subglacial volcano Katla erupts, roughly every 40 to 80 years. The eruption in 1755 is estimated to have had a peak discharge of 200,000 to 400,000 $m^3/s$. > > > Therefore you just need to take Iceland example and expand it on a larger scale: you have already extensive ice caps, since the planet is cold, so you just need to add large scale volcanic activity. [Answer] > > "I want the planet to have a cold climate, so I can’t simply explain the flood by saying it was global warming (because then the planet would be too hot)." > > > That's no problem. Just have it warm up from 'very cold' to merely 'cold'. When an ice age ends, the ice sheets melting can release large floods when meltwater is pent up behind ice dams that suddenly break. Consider the real-world example of [meltwater pulse 1A](https://en.wikipedia.org/wiki/Meltwater_pulse_1A) which raised sea levels 16-25 metres. Although the globe was warming, it was still globally [colder 14,000 years ago](https://en.wikipedia.org/wiki/Younger_Dryas#/media/File:20191021_Temperature_from_20,000_to_10,000_years_ago_-_recovery_from_ice_age.png) than it is today. Although very abrupt climate change with [jumps of 5-10 C](https://en.wikipedia.org/wiki/Younger_Dryas#/media/File:Younger_Dryas_and_Air_Temperature_Changes.jpg) can occur in a matter of a few years (e.g. The [Younger Dryas](https://www.livescience.com/7981-big-freeze-earth-plunge-sudden-ice-age.html)), Meltwater Pulse 1A is thought to have taken about 400-500 years, so that may be a bit slow for your purposes. If you want something a bit faster than that, I suggest volcanoes, earthquakes, landslides, tsunamis, meteorites, etc. Also have a look at the [Zanclean flood](https://en.wikipedia.org/wiki/Zanclean_flood), or the similar event postulated for the [Black Sea](https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis), for another idea. [Answer] Salt Meteors or Meteorites <http://www.psrd.hawaii.edu/Nov99/PurpleSalt.html> A large enough salt meteor or shower of salt meteorites spiked salinity levels within a large enough region and de-iced a large enough portion of the planet to cause global sea level rise of about 30 meters. After the sea level rose, and salinity concentration became diluted (or reason X, like the additional salt reacting to existing chemicals on the planet and causing them to fall out of suspension as sediment, etc.), then the water is able to freeze again. [Answer] Ice dam breaks. [![ice dam](https://i.stack.imgur.com/4hTFf.jpg)](https://i.stack.imgur.com/4hTFf.jpg) <https://www.youtube.com/watch?v=Zy_m_2zQFX4> I think this was done best in the movie Ice Age: the Meltdown. I like the squirrel and it should be in more movies. But it happened for real in our world. The Missoula floods were big ones. Lake Missoula was formed by melting glaciers and the water impounded behind an ice dam. [![lake missoula](https://i.stack.imgur.com/i4ICo.jpg)](https://i.stack.imgur.com/i4ICo.jpg) <http://hugefloods.com/LakeMissoula.html> When the dam broke (probably because of a squirrel somehow) the water rushed across the land and seriously washed things away. Similar actions on the North American East coast formed the Hudson river valley. You can check out images or maps of these places for ideas about topography formed by megafloods. That said, in our world it was not enough water to raise sea level 30 meters. But the principle is sound. If your world has small and shallow oceans relative to Earth, and a colossal amount of water locked into glaciers on one of your continents, a relative thaw and unfreezing of some of that water could wind up with a continent spanning meltwater lake, and then a big dump into the ocean. Several big dumps might be more realistic; that is apparently how the Missoula floods worked, although I read somewhere that the Hudson River Valley was carved over the course of a week. That does not mean your world needs to get hot - a transient heating and melt for some reason will do. I like a volcanic eruption not for hot lava and heating (too local) but ashy eruptions that paint the glaciers black and alters their albedo. Or a Fortean rain from space of nitrogen and phosphorus that stimulates the snow algae... and alters glacier albedo. [Answer] This is roughly the same problem that creationists face in explaining the flood of Noah, therefore we can borrow [some of their theories](http://www.creationwiki.org/Flood_model) for this case. Canopy Theory: Some layer of water surrounded your planet and eventually became rain due to a disturbance. This could be a layer of water vapor maintained by same (possibly biotic?) phenomena, or a belt of water-ice that got disturbed by a passing body or caught by an expanding atmosphere. Hydroplate Theory: Water is fairly common in the universe, so it's not that outlandish that there could have been huge aquifers beneath the earth that eventually emptied themselves due to the movement of the tectonic plates. Catastrophic Plate Tectonics If your planet has oceans, all you need to do to flood it is have the ocean floor rise significantly and rapidly. The creationists have proposed somewhat plausible mechanisms for how this could happen. Disclaimer: This answer was written with the intent to neither endorse nor condemn creationism, but merely to borrow inspiration from the thought given to the problem. [Answer] The only plausible ways I can think of that don't also create sea level rise from global warming is to have some large amount of ice or water trapped above sea level and suddenly released. There are parallels to both in Earth's geologic history, though on a smaller scale. For an ice-based flood, imagine a polar continent where the ice sheets are even more delicately-balanced than Antartica's are. Some event such as an earthquake or volcano breaks the keystone of that balance, causing a catastrophic collapse. On Earth, a collapse of the West Antarctic ice sheet could cause a sea level rise of about 4 meters: <https://news.harvard.edu/gazette/story/2021/04/study-says-antarctic-ice-sheet-melt-to-lift-sea-level-higher-than-thought/> Just increase the size of the collapsing sheet as needed for your world. For a land-based flood, imagine we have a large, closed basin at some elevation above sea level, something like the Great Basin of western North America, but larger & deeper. This collects water over the ages (perhaps it's not in the rain shadow of the Sierra & Cascades), until it finally over-tops the rim. The rock at that point is fairly weak, and erodes, emptying the basin in weeks or months. This actually did happen, though not on a large enough scale to affect global sea levels: <https://en.wikipedia.org/wiki/Bonneville_flood> The catastrophic filling of the Mediterranean & Black Sea basins are similar, though they would have lowered global sea levels - an anti-flood, if you will. [Answer] 1. Sudden stellar flare. Either by itself (red dwarfs are [especially prone to month-long flares](https://www.nasa.gov/feature/goddard/2018/superflares-from-young-red-dwarf-stars-imperil-planets), but perhaps not so much as to [rule out habitability](https://earthsky.org/space/red-dwarf-stars-superflares-red-dwarf-planets-habitability/)), or a collision with a (hot) jovian planet (but that will take thousands of years to stabilize) or even simpler: 2. (big) meteorite impact directly on the icecap, resulting in the icecap melting [Answer] It's a cold(er) climate but there is still liquid water. So frozen water entering the planet would become liquid, generally. So, you just need a giant ice meteor that evaporates into, basically, really thick, clouds as it enters the atmosphere. This gives you mass amounts of suspended water (briefly) as it begins a slowly circulating global-level thunder/rain storm for the next 4(99?) years [Answer] [![enter image description here](https://i.stack.imgur.com/QEgSb.png)](https://i.stack.imgur.com/QEgSb.png) [Source](http://www.antarcticglaciers.org/glaciers-and-climate/sea-level-rise-2/recovering-from-an-ice-age/) Baby geologist here. You don't need a flood. You don't need anything exceptional. As ice ages develop, sea level goes up. Well, let me actually clarify a bit--the coastlines go up. There's less water in the oceans--it's all turning to ice through the precipitation cycle--but the shores still go back up the coast anyways. Why? Well, because rock's a fluid on geologic timescales. Imagine you're in a boat, and then somebody puts a bunch of stuff in it: the boat's going to settle. In this case, the continents are a boat floating in a sea of rock, and all the ice developing is the stuff. We call this state [isostasy](https://en.wikipedia.org/wiki/Isostasy), and when you add ice to the continents, you disrupt it. That's right, baby, it's [isostatic depression](https://en.wikipedia.org/wiki/Isostatic_depression). When you cover the planet in ice, the continents sink into the earth a bit & the coastlines go up, [by up to 200 m](https://digitalcommons.tacoma.uw.edu/cgi/viewcontent.cgi?article=1338&context=ias_pub) during the last ice age. The opposite is also why sea levels are [still falling on Canada shorelines](https://www.academia.edu/download/42032414/A_new_glacial_isostatic_adjustment_model20160204-32010-wmldgg.pdf) today--North America is still [rebounding](https://en.wikipedia.org/wiki/Post-glacial_rebound) after all the ice came off a short 10s of 1000s of years ago. EDIT: Surprised to see downvotes without comments. Added some sources for you skeptics. [Answer] A nearby supernova inside a cloud of dust. The supernova released an immense amount of heat and light, but this energy was trapped by the dust cloud that surrounded it, heating the dust cloud to many thousands of degrees. For a year or two, there was a moon-apparent-diameter "second sun" in the sky, that gave of immense amounts of infrared heat, heating the planet surface by 10-15 degrees C. This has caused a mass melting of the polar caps, ice sheets and glaciers, thus raising the sealevel by a lot. After several months, maybe a year, the cloud cools below visible, and within 5 years it stops emitting any significant infrared heat, thus allowing the planet to slowly regain its old thermal equilibrium. The planet is a cold planet again. However it will take millenia for the water to be deposited into new icecaps, icesheets and glaciers. The fun is over. For now.. In about 5000 years, the shockwave of that dust cloud that got clobbered by the supernova will reach the planet, and then all hell breaks loose. Assumptions: * The supernova is a bog-standard type 1a, thus emitting about 1e44joules * it is at a distance of 20-30ly when it pops. (to provide enough energy to heat the planet by 10C for 1 year) * You make no mention of global radioactive devastation, mass dying-offs, or really weird mutants flying around. Something needed to shield you from the intense gamma emission of the supernova, but still allow the heat to reach your planet. Hence the small and very dense dust cloud. * The dust cloud got heated to 10000K or so. So a lot of UV, tapering off to IR over time. This heats first the upper atmosphere, then the surface. * In the process, the dustcloud got kicked to a linear velocity of about 1200km/s. It will arrive in 5000 years. And it will hit like a good solid Coronal Mass Ejection (think Carrington event) that goes on and on and on nonstop for a thousand years. [Answer] A relatively small ice shelf on a coastline is holding back a continent's worth of glaciers from sliding into the ocean. Picture a massive polar continent covered in ice sheets and glaciers (Antarctica but bigger, maybe). The geology of the continent is such that a majority of the glacier flow all converges to a coastline that has a significant ice sheet in the water that effectively "dams" the glacial flow. Or perhaps there are multiple convergence points, that are all dammed in a similar way. The minor warming of your planet has been just enough to allow the ice sheet dam (or dams) to weaken and break away from the continent as massive icebergs. These icebergs themselves will not cause an increase is sea level since they were already floating on the ocean. However, without those dams in place, the continental glaciers are now free to dump their contents of centuries (millennia?) of accumulated ice and snow into the oceans, which will cause a rise in sea level. The timeframe of this may be not be swift enough for your story as the pace of this flow of ice into the ocean will be, by definition, glacial. It could be a contributing factor though. ]
[Question] [ Closed. This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 5 years ago. [Improve this question](/posts/132672/edit) This is an idea that I've been wondering about for awhile now, and I can't come up with a satisfying answer. Most of the reasons I've come up with are pretty petty, and considering that this would be a very harsh curse, I don't think that a petty reason will cut it. In context of the curse, it would make it so that people who are cursed are forced to hunt monsters down, or suffer mental and physical consequences. It's not one of the worst curses, but it is pretty close. P.S. I apologize if what I'm trying to say isn't clear, because I do have issues communicating ideas sometimes. Also, if this doesn't fit the guidelines, please let me know and I'll try to fix it. [Answer] I am literally writing a fantasy story with a character like this. The character has murdered people and got caught, he gets a choice: the death penalty or get cursed to roam the lands and hunt down monsters and demons while avoiding people as much as possible. The curse makes them live for the hunt while becoming uneasy to downright in terror when near groups of people. Of course the curse isn't perfect and a story ensues. This is a criminal that people want to get rid off rather permanently, so sending them out to do dangerous Jobs that will kill them eventually and protect people with it seems to be a perfect atonement for their sins and a delayed death penalty. [Answer] Have you ever heard of vampires? You can modify this basic idea as you wish, e.g.: * The curse is not directly making the person to hunt, but to lust for flesh/blood (and monsters can somehow be more favourable as a prey) * The curse itself can be contageous, so the character can get bitten by another "vampire", because the said "vampire" urgently needed a way to satisfy his hunger. If the question was about "why would one will to bestow this curse on himself", then it can be literally anything, limited only by imagination, starting from it being a side-effect from a deal with some demon/monster, ending with your character being young/stupid/not-really-knowing-what's-he-doing. [Answer] The monsters have some ability that makes the curse necessary. Bandersnatches are fierce and terrible monsters who love eating small children. But they have a psychic ability that makes people near them forget why they are there, or want to run away, or makes the Bandersnatches look like loved ones. To overcome this, the curse was devised. It forces the chosen hunters to fight Bandersnatches even when under the Bandersnatch's power. It's not a fun curse, but it's a necessary job. [Answer] It's a win-win situation for the witch/wizard/gypsy that cursed them. The witch doesn't like all of these monsters roaming around, and wants to thin down their numbers. The witch also doesn't like some poor sod for whatever reason, and wants to be vengeful against that specific person. So, they place a curse that the person must eat a monster's heart/ bathe in a monster's blood once a week, or else suffer unimaginable pain. The person is doomed to a life of torment constantly hunting monsters, and the witch is cackling. There's nothing of value lost to the witch; only two inconveniences matched against each other. The curse could be like an addiction; the victim becomes an addict, and the only way to get a fix is to kill a monster. The witch wants to get the best possible use out of her power; fewer monsters and fewer enemies. Alternatively, you could easily replace 'witch' with 'government', 'military', 'church' or 'cult'. Perhaps the curse is a punishment used to run them of prisoners or undesirables. Instead of a hangman, they sentence people to death by monster hunting - a brutal form of community service, perhaps. The reason why might be extremely petty indeed. It could be as much about getting rid of the person as is about getting rid of the monsters. Alternatively, you have an effective means of turning a person into your slave. It is the ultimate torture/control. Any evil tyrant would spam the hell out of the ability and use it as much as possible. [Answer] In the times before your story, a tribe of people while fiddling with magic ended up releasing these monster into the world, and where not able to close the portal releasing the monsters. As a consequence other tribes investigated the issue, and when the guilty were found they were cursed to hunt down the problem they created, or to suffer stronger consequences. [Answer] ## The monsters search for the cursed human I think you have this the wrong way around. The curse does not make the criminal hunt down monsters, it is sort of target placed on his back. The target draws nearby monsters to the criminal and he must kill them or die. This is a death sentence and torture in one, because the criminal cannot sleep without the chance of something dangerous stalking and killing him. As a bonus, monsters are drawn away from the rest of the area giving some relief for normal villagers with the potential of the criminal being successful in killing a few. [Answer] The curse might cause terrible pain (over time). And the only possible way to ease the pain is to wash yourself in monster blood or get blessed by a member of the church. * It might be a way to solve the curse by slaying a demon general or higher, or be blessed by a bishop. * The pain + might be a very worse memory that gets implanted with the curse, which the cursed person must go through again and again. The monster blood might be a drug that makes you high enough to endure the memories. The severeness of the curse may differ from the implanted memories. + Or the curse could be a monster, which eats the cursed all the time until the cursed give it some monster to eat. That could explain gaining special powers as cursed (from the monster). The blessing of a member of the church stalls, or stuns the monster curse I hope this helps :) [Answer] In a slightly less punishment driven scenario your curse could have a viral component. When the current holder of the curse dies, the curse passes to the nearest person who is then filled with the compulsion to hunt monsters. If you'd rather make it a bigger problem, the curse could be more easily transmitted, perhaps as an STD. If the curse is a well known issue within your setting, this could lead to some interesting social issues as well, depending on how strongly the compulsion manifests. Under this type of curse, the individual(s) who are cursed don't have to have done anything wrong themselves, they're just in the wrong place at the wrong time. This could equally lead to people who are spectacularly unsuited to being monster hunters being the victims of the curse. [Answer] The curse is lethal but not instantly, the victim slowly weakens and eventually dies. There is no cure but there is a temporary antidote: the monster's heart (or other body part). The condemned man is forced to hunt and eat the monsters, inevitably he will not be able to catch a monster in time. So it works like a combination community service death penalty. With the advantage that no guards or enforcement is needed after the hunter is cursed. As to why such a curse would be devised: monster hunting is super dangerous, nobody does it if it can be avoided. To get monster hunters you've got to make the need to hunt unavoidable. [Answer] The monsters came into the character's life when he was young and killed all his loved ones before his eyes, or dragged them away into slavery, or something similarly traumatic. This snatched the character's childhood innocence away and changed him forever; he now makes it his sole purpose in life to hunt down and destroy all the monsters. Non-magical only Monster slayers are ostracised and looked down upon in society, like night soil collectors or sin eaters. This is because monsters mainly afflict remote villagers who can't afford to pay well for monster exterminators, and also because since monster activity takes place in rural activities, society at large takes an "out of sight, out of mind" view to their existence. Yet at the same time, your character cannot simply walk away. His childhood memories and need for vengeance compel him to hunt them all down. The curse here is mental and social, but not physical. Magical The monsters are werewolves who also bit the character and thus marked him as one of theirs unwillingly. The character hates all werewolves for forcibly "recruiting" him as one of their own, and thus seeks to wipe them out of existence. With this, your character would bear the physical downsides of lycanthropy like a thirst for blood, as well as the additional burden of self-loathing. This can be added on top of the purely non-magical option. ]
[Question] [ World War VI happened in year 2xxx and the government went AWOL. No federal, state, county government. Chaos and anarchy ensued, and Charles Hestion IX [1] felt his ancestor's efforts paid off. Ammo and guns are the most valuable commodity. Now the dust has settled a bit and some communities are forming, there is one point I am unsure in this society: What value does gold bullion and jewelry have, when you can barely get enough water and food to survive? [1]: any similarity to a XX century movie actor is mere coincidence. [Answer] Gold and jewelry have a value outside of their "intrinsic worth". Guns and ammunition will be valuable commodities (so long as they work, which might be only a period of decades), but we know that art has a great value as a marker or signifier: The owner is both signifying and displaying their wealth and power because they can afford time and resources for things which are not intrinsically valuable. A peasant will be spending all their available income on the very necessities of life, food, clothing, shelter and a bit left over for things like tools so they can work the land. Minor nobility could afford better clothing and shelter, as well as the tools of the trade (normally weapons and armour). As you ascend the ladder of social and economic class, you could afford to spend less and less on the necessities of life, and more and more to demonstrate your position and relative power in life. Since there were various ways to get around class and economic boundaries, there were even laws in the Middle Ages in Europe specifying what could be worn by what classes of people (a peasant who found some coin or managed to capture and sell a warhorse and armour would be fantastically wealthy by the standards of his village, but woe betide him if he were to start buying and wearing fur tried clothes, for example). Perhaps luckily, most of the time these laws were ignored by the majority of the people, and rarely enforced. So gold and jewels will still have value in a post apocalyptic society as markers of who has power and status in this new society. [Answer] While most "survival" scenarios do place value on gold, silver, and the like, the actual worth of these things greatly depends on the situation. In bare subsistence survival, like everyone is starving to death, only directly useful items are likely to carry much worth. Currency, defined as something that itself is not usable, but has a value assigned to it, can only really exist when there is an authority that places value on it, and, to some extent, determines what that value is. So if there is a guy with a huge storehouse of MREs (and he is the only one in the area) who declares that 1 gold ring or pre-1964 silver quarter is worth 1 MRE, then that value of currency will exist in the local area. So two survivors could trade other things using gold/silver (I'll call them PM, precious metals, now) as currency since there would be a known useful value. But if the MRE guy DOESN'T take PMs, and no one else has a stockpile to initiate a barter system using PMs, then gold/silver will be worthless since it has no direct survival value (outside of some electrical repair work, perhaps). There needs to be SOME level of society for PMs to have value. Even as ornamentation the basic needs of food, water, and shelter come first. So either there is an elite class that is living above subsistence that determines that gold has value or there is an adjacent civilization that does. This is why PM has value in a POW camp. Prisoners can use it to trade with the guards since guards have access to civilization. If trade was only between prisoners then PM would have little to no worth (versus food, cigarettes, etc). Given time, when communities have developed, then PM will regain their value. Of course since modern society has flooded the market with jewelry it may not carry the same sense of scarcity as it did in earlier times (unless jewelry stores, department stores, pawn shops, etc have all been destroyed). Gold and silver are uniquely suited for coinage since they don't corrode or rust, are easily worked by primitive technology, and can be distinguished from forgeries/adulteration. But this is only with a pretty high level of society compared to survivors scratching out a living in the rubble. Otherwise value will be in direct labor or trade of items with inherent use/value, like tools, raw materials, food, seeds, etc. On a side note, I doubt most folks today even know the actual worth of a gold coin, or how to recognize one from a fake. They DEFINITELY don't know the value of pre-1964 silver coinage. I bet the old "gold rolex survival plan" wouldn't even work, as lots of people today wouldn't know the value of a rolex or believe it wasn't a fake. Immediately after a disaster people would take CASH, at least until it became apparent that cash (bills and coins) only had value as firestarter, insulation, weights for your fishing line, or hammered in to arrowheads because the world isn't coming back. In a total collapse scenario PMs and cash have virtually no value. [Answer] Gold is a really handy medium for exchange. You can't eat it, build with it, or make primitive tools out of it (you can make complex electronics with it, but by the time you're making complex electronics you've probably moved away from a gold standard anyway). It doesn't tarnish, rot, or spoil, and nearly everyone can agree that it has value. Guns and ammo are valuable commodities, true, but ammo is also consumable - once you've fired a bullet, you can't re-use it. This makes it a poor medium for exchange. Guns are too big to be used as a form of exchange - if you have two rifles, and I have a gallon of water, you can't give me half a gun to buy the water - it's the whole gun or nothing, and then you only have one rifle. You're not going to be willing to make that trade. It's historically unclear whether a true barter economy, where goods with utilitarian value were traded for other such goods, has ever really existed. It appears that within groups something akin to communism or socialism existed, where everyone got what they needed and did what they could, while between groups trade took the form of a mutual exchange of gifts. I might gift you with a years supply of water, and you might give me a rifle in return; both of us have gained in the transaction, and we'll be more likely to trust one another next time. On the other hand, if you have two rifles and ten gold rings, and I have a gallon of water, you can give me two rings for the water and not have lost anything vital. I'll accept the rings, because I know the guy on the next farm has some potatoes, and I know he'll accept gold rings as payment. I also know that if the flesh-eating were-rabbits of Golgotha have snuck in and eaten the farmer before I get there, I can hold onto the gold until I can buy the pretty daughter of the wandering trader who comes through. It won't lose value by tarnishing, and I won't need to shoot it at said were-rabbits; its value is secure. In the end, any medium of exchange has value because people agree that it does. Gold is perfect for that use. If everyone really is at the subsistence level, and nobody has anything to spare anyway, that is the only time that gold will truly lose all its value. [Answer] A lot of answers are avoiding the core question and confusing uses of currency with the value of ostentatious displays of wealth. *What use is Gold and Jewelry?* Gold has a number of qualities that makes it good as a currency: * It is fungible. You can relatively easily divide it into any fraction you want. This means that you don't have to trade a whole thing for a whole other thing: you can scale the amount you trade according to the perceived value. * It is durable. While cigarettes, food and other things can and are used as currency, because they have a shelf life that use is limited. Gold has no shelf life. * It is portable. Relatively small amounts of gold can account for larger amounts of "wealth". It is easier to move a nugget of gold than three goats and a pail. This makes it useful as a "store" of wealth, because the management overhead is low. * It is homogenous, meaning that all gold looks, tastes and weighs the same as other gold. (This is why animals as currency is difficult: an old cow is different than a young bull.) * It is recognizable, meaning that it doesn't take a lot of brainpower to verify gold is gold, and conceiving relative amounts isn't hard either. * It isn't abundant: that is, there is a finite new supply of it. If someone can create or find currency without a lot of labor then inflation undermines agreed value. Jewelry has some of these qualities but not others (fungibility). In fact, many things express many of these qualities but soft precious metals express the most, and the most strongly. Now we have established gold makes a good currency. *What use is currency?* And, especially, what use is it in a subsistence environment absent a force-wielding authority government? Trade seeks to maximize utility: if you have wheat you're not eating and I have goats that are starving it makes sense we trade those in some measure to balance out. That way we both can profit by getting rid of stuff we aren't using in exchange for stuff we can use. If everyone is engaged in acquiring food, but they are not acquiring enough to feed themselves, then currency is near useless. The total food being produced is less than is needed: trading does not help so tools of trade aren't necessary. If however some people are producing more than they need, then they will want to trade the excess to people who could do more useful things than farm. The idea here is that the most efficient food producers should produce food, and everyone else should do other things that are needed. In these and more complex scenarios trade and a means of trade are useful. However, currency is only worthwhile if people generally agree on value. If all cultural understanding of gold has been wiped out through loss of knowledge or simple sparsity of people (such that no trade culture exists), currency and gold is still useless. If this environment exists in your setting then it should be clear if gold or other ideal or near ideal currencies "are useful". Note that while currency has a primary use in trade, it can be used as a display of wealth and power. Anything can be retasked in this manner: a walking stick can be a weapon or paper money fuel for a fire. Whether that repurposing is effective depends on the environment: ostentatious display of wealth isn't useful if few see it. [Answer] You are mixing two concepts: Wealth, and the ability to use it. Using jewelry as a form of wealth undoubtedly works. It has been used as currency time and time again, therefore it's pretty simple to deduce that it will be used as currency once more when society collapses. This brings us to the problem of using wealth. In current times, most people in the middle and lower class of western civilizations can freely use most of their wealth. This hasn't always been true. If you have lots of money, and someone else has a gun, while you do neither have any ability to defend yourself nor an ability to retaliate, the money still has value, but if you try to buy the gun, the gunman simply takes your money and keeps the gun. Nowadays it's the threat of retaliation by law enforcement as well a societal norms that prevent that. In a post-apocalyptic society you don't have that. Even if a tiny local militia and a court of law exists, there's not much if anything preventing them from taking your stuff. In order to use your wealth you need social stability and social status that allows you to own, and to trade. Without these that, every form of pure wealth is useless; even dangerous, since it provides a motivation to rob you. --- Example: Say you are a slave, and you find a treasure. The value of treasure is more than enough to buy your freedom. Nobody will dispute that the treasure is wealth, but as soon as you attempt to trade the treasure for your freedom, people will just take the treasure away. [Answer] > > Now the dust has settled a bit and some communities are forming, there is one point I am unsure in this society: > > > What value does gold bullion and jewelry have, when you can barely get enough water and food to survive? > > > ## Your Mileage may vary... It depends on what your society uses for currency. Currency is handy because it means removing the middle man from barter and trade, you can get what you want by giving the other person something they want. It allows someone who does not want the clothes you are selling, to sell you the pig you want without having to get him the pigfeed he wants from the person who actually wants clothes. Instead you simply give him money for the pig, and he uses money to buy pigfeed What does currency offer? * Standardized * Easily traded * Rare enough to make it impactful * Common enough to be reasonably useful in an economy of some arbitrary scale ## How does this affect my budding society? To answer your question, you need to answer some questions about your society as it forms. Put yourself in the shoes of someone living in one of these communities and ask yourselves about some of the following... What situations does currency depend on? * Agreement of a community at large, to assign some non intrinsic value to something to make it a useable currency. * A general cooperation among the community to properly assign the same value to equal amounts of the same currency. Do people in your communities do these things? If so it might be reasonable to form a system of currency for them at some point. In that system gold and metals like it may have a place, though it is not required as some post apocalyptic scenarios value other things. For example, The [fallout](https://en.wikipedia.org/wiki/Fallout_%28series%29) video game series shows a society in which soda bottle caps are the valued currency of choice. While something like gold has some good intrinsic properties, it may only rate being 'worth a glass of water' or a handful of 'bottle caps' if the society has no need of these properties. Thankfully gold is shiny and easy to show off. It has always been valued as a sign of affluence for this reason and that alone usually has power to make it valuable. ## Sounds good, except for... Before you decide what kind of currency or lack thereof your society works with (or without), you should also answer the following. Note that during the thick of the end of the world, most of the things listed below are likely true. If in these communities they are still largely true, it may make currency a difficult proposition. When would currency potentially be less valuable as an idea? * Situations where no one is sharing * Situations when it is seen as more efficient to take rather than to trade by at least one portion of a society ## In conclusion At the end of the day your people will require a trust in others that when they offer a currency (be it gold, bottle caps, water, cows or rabbits) they can get something they need, like food or ammo. If it is easier for people to use the ammo and steal (it may be for a while at least) then such a system likely will not become widespread until it is more efficient to trade peacefully rather than rob violently. If you cant reasonably arm yourself with a gold ring and expect it to be generally useful as a bartering tool then it wont be valuable. [Answer] # Very little, and then a lot In the immediate aftermath, currency is useless. People need food, water, clothing, medical goods, and weapons to survive. It is unlikely that people will trade away any of their precious goods for anything less than that, unless their are personal needs (such as a survivor desperate to record their experiences trading for a pen and a journal). Anything else is a paperweight. However, once some level of stability is achieved, a medium of exchange will be necessary. Gold and jewels hold their value well since they don't rust or tarnish, which is why they have been used as a store of value for a long time. Eventually there will be a need to finance larger ventures than subsistence, such as setting up irrigation, farms, factories for clothing, weapons, medical supplies, and so on. The instrument to build such things would most likely be debt backed by gold collateral, unless Communism makes a major comeback. Keep the guns and the gold. [Answer] "An object is exactly as valuable as people say it is". So most likely, they would be worthless trash. They contribute nothing to your survivability, and it does nothing to demonstrate your power over others. If people BELIEVE that gold and jewelry makes them look 'more powerful', than its value would be proportional to the amount of power it is believed to represent. For example, Purple dye was REALLY hard to make back in the day, so royalty wore it to show off that they COULD. Now Purple is just another color shirts sometimes come in. [Answer] Gold is a handy metal. It's conductive, workable by hand or at low temperatures, reflective, and insertable into the body without causing instant infection. Yes, it's also pretty. So society falls, but we have the stuff. Broken whazit? Use gold! You can melt down some jewelry over a torch and reform it in a whazit part. Useful stuff. Want to impress your woman of the hour? Show off some gold; you can fix anything! Gold isn't valuable because its rare. Gold is valuable because its rare and awesome! [Answer] Here is what happens when you break down the societal structures and such a massive level: Society will be broken into smaller city-states or tribal communities where the strong (and often unjust) become the dominate political force in each region. There will be a heavy distinction between the working class and the warrior class... and in fact, its very likely there would be what we would consider as slavery (forced occupation with very little pay). If water and food are precious, it wouldn't matter how much value gold or jewelry would have... people in need with these items would sell a $100,000 item just for a cup of water. Also consider the fact that old world products may actually be more valuable than gold. For example: medicines, coffee, chocolate, metal and plastic goods, clothes, gasoline, dynamite Gold and jewelry will not start to have a standardized value until after the society begins to stabilize and the people move beyond basic necessities. You need to have communities that have surplus of food in order to take to market... and other communities that have need of food but have other commodities just as much in demand (like coal, hardwoods, salt, herbs and spices, etc). Only after a period where direct bartering is no longer efficient would currency start to exist. [Answer] I would point you towards Diablo 2's economy for an example of "survival" economy before you get to actual economy. In D2 there exists gold that isn't considered valuable by anyone; and then many other things that are somewhat valuable. It's a true bartering economy where things that approach Currency are Runes; which are consumables of a sort. Note: This is the same with Path of Exile; which did away with straight currency altogether and instead has consumable currency. What this means is that while the currency building functions of combining lower forms into upper forms regulates it's maximum value to a degree, it's not just scarcity driving it's value. It's scarcity + recognition as a useful trading item, as well as being small enough that you can store a lot of it. If people don't want a rare and good item, because better items exist; it has next to no currency worth, but may be worth your time to use it. This is to put perspective on visible real economies of games that roughly mirror your survival scenario. [Answer] As it has no intrinsic, use based, value gold and jewels are worth what they've always been worth, what people are willing to pay for them. If you have a warlord elite willing to pay top dollar to salvage experts to go get their favourite painting from a museum in Boston (yes I'm stepping on S.M. Stirling's literary toes slightly there) then the work is worth top dollar, or its equivalent, if however the elite are scraping a living as much as the peonage who work for them then if you can't eat it or use it to get something you can eat, if it doesn't keep you safe from the big bad world around you it's useless and thus worthless. So the question of value is really one of how much the world has settled down and what shape it settled down into. [Answer] The OP says: What value does gold bullion and jewelry have, when you can barely get enough water and food to survive? Virtually none. This is the scenario: Your character: A healthy male in his 40s, thin, but you have not had food in two days, and you haven't had water since yesterday. You are exhausted and have nothing stashed. The land is picked over so there is nothing to be found to eat. It hasn't rained in weeks and rainwater is the only thing you trust to be uncontaminated. You come to a fork in the road, literally, with recruiters offering you two different deals. Presume, for the purpose of focusing this example on the true dilemma, that you can trust both men to keep their word; they will give you what they promise, and you must give them what you promise. Both men are charged with recruiting a workforce to build, break land, and clear forest for newly formed farming and ranching communities. Neither man will tolerate a changed mind: If you turn them down, you cannot return later to take them up on their offer. The men are friendly with each other, their communities will be sisters. In exchange for an apple from their shared bag, they examine you thoroughly, both wish to make you an offer. The work is the same hard labor for both: carrying bags of concrete, pulling carts, digging with pick and shovel to clear land, building stone walls. You will work your nearly dead body for 12 hours a day. On your left is Aaron. He offers you, in return for each hour, all the clean water you can drink, and 500 calories of vegetable and chicken soup (with bread), and 10 minutes to consume them and rest. Every hour, you will work 50 minutes, and for 10 you can eat, rest, eliminate, etc. At night you have 12 hours of shelter (a tent), a community fire, and the companionship of your fellow workers if you want it. Altogether, you get 6000 calories a day, about what you will burn for a hard labor life. On your right is Bill. He offers you, in return for each 12 hours of work, a gold coin worth, IRL, about \$100. So about \$8.50 an hour, like a low wage job in 2017 America. He will also offer you a tent and community fire, but it is up to you to find and buy your water and food. Note that IRL, Aaron's deal is not even close to minimum wage. There are 1085 calories in a pound of chicken, which is always available at my grocery store for about $2/lb, so roughly 500 calories per dollar. This means 6000 calories of chicken, IRL, costs about \$12. For 12 hours of work, that is only \$1 per hour. But this is vegetable chicken soup, and many vegetables cost far less; see [This Chart](http://efficiencyiseverything.com/calorie-per-dollar-list/), which is a little out of date but still has the rankings of food by cost per calorie roughly correct. Many of these foods would not be available in a post-apocalyptic society, but presumably food and grain still grows, and chickens can be fed on peas, corn, beans and insects (e.g. termite farming can provide a good source of protein for chickens, and the chickens will do much of the work once you stir the nest). So let us say that in the end Aaron is offering you the equivalent, IRL, of 42 cents a day, $\frac{1}{20}$ of what Bill is offering you, \$8.50 per day. Yet most of us take Aaron's deal. There is no guarantee we can buy food or water, Bill is not promising to sell it to us, he offers us only the gold. Our fellow workers, in Bill's camp, don't necessarily have food and water to sell us, and we don't know where we would buy it (except perhaps from Aaron's camp, but workers there don't get to hoard food or water in order to sell it; they consume their pay each hour and that's it). Here is the major misconception people have about currency, rarity, and "intrinsic value": None of that matters more than trust. If your hungry and thirsty character, the worker above, has no faith that they will be able to trade a gold coin for food and water, then they will not work the first day for a gold coin. A currency does not have to be "rare" to have value, the only demands are that it is difficult to create counterfeit money (a trait that rarity can provide, but see my note on rarity below), and that the holder of the currency is virtually certain they will be able to trade it for goods and services they want: They have faith in the currency. Note on rarity: The physical rarity of materials (like gold and jewels) is not the only thing that makes an item hard to counterfeit; our own paper money is difficult to counterfeit. "Difficult to Counterfeit" is really an adjunct to faith and trust in the currency; if it is not difficult to counterfeit, nobody will trust it. If it is subject to wild inflation, or fluctuates too widely in trading value, then nobody will trust it either; meaning they won't believe it is worth, approximately, the same amount of labor it took them to get it. So in the end, the value of currency is all about whether almost everybody believes it can be exchanged for goods and services. It is not about rarity, or inherent value, or utility. It is about belief. If nobody in your world believes gold and jewels can be exchanged, quickly and easily, for the food and water in scarce supply, then gold and jewels will not act as currency. They will be worth about what pretty stones and shells are worth. In a post-apocalypse society, the most plausible outcome to me is that tools, weapons, food and sometimes medicine will be far more valuable in trade than gold or jewels. [Answer] Any commodity has a use value, which resides in its usefulness, and an exchange value, which is how it relates to other commodities. Currency is a particular kind of commodity in that its use value is to function as means of exchange. So it is exchange value is what gives it a use value, as a reverse to what happens to other commodities, related to which, it is the use value that gives them an exchange value. Now, means of exchange will only have value if there are exchanges taking place regularly. That's what you must make clear to yourself: to what extent the apolyptic destruction of society that took place in your story background destroyed the possibility of organised exchange, and to what extent the reconstruction that ensued has rebuilt such possibility. If your post-apocalypse consists in small, isolated communities, then they in all likeness will distribute goods withou the mediation of markets, and will have no need for an internal currency. And if they trade with each others, it is likely that such trade will take the form of barter, in which they will look for use value alone, not for exchange value. If on the other hand there are organised States, with armies and police, then quite probably such State will mint money \*and that money will be made of gold or perhaps silver), or it will enforce the circulation of old pre-apocalytic coins. Fiat money will require much further economic development, probably something like an industrial economy or at least a very developed agriculture with private property of land (such as mediaeval China, for instance). If you decide that social ties have survived or redeveloped enough to sustain organised trade, then the value of gold should be its exchange value, which is, the amount of labour that it is necessary to obtain it, compared to the amount of labour that is necessary to produce other commodities. In short, the value of the total circulating gold (silver, bronze, platinum, nonobtainium) should be equal to the total value of other commodities, divided by the speed in which it circulates. [Answer] In a post apocalyptic world, the survivors would rediscover the drawbacks of the barter society. Thousands of years ago, before civilizations had advanced into full commerce, you had to find someone who had what you wanted, and wanted what you had to trade. That is rarely the case. Your best hope is to trade what you have, for something most people will want. This is why emerging civilizations thousands of years ago, came up with the concept of currency - a medium of exchange that everyone would accept. Sell what you have for currency, use that currency to buy what you want. Currency was the first great invention of early civilizations. Post apocalyptic societies will also rediscover this handy aid to local commerce. Early on, societies settled on gold as the first currency. It was one of the first metals that pre-industrial humans could work with. It is a durable metal: not prone to corruption, not needing special storage like grain or bread. It comes in graduated amounts - by weight. Finally, its purity is easily ascertained. In early societies, traders would carry a touchstone: an abrasive black stone. They would rub genuine gold on it, leaving a colored mark. When someone offered them gold, they would rub that next to the genuine gold, and compare the color. Any impurities in the gold, or fake gold (as in fool's gold), will produce a different color. Being able to ascertain the purity of gold easily was a big advantage, when the purity of other metals was harder to determine. On top of that, the post apocalypse will be looking forward to the time when civilization resumes, as eventually it will. So there will be a natural tendency to hoard gold, looking forward to the time when its value will increase dramatically. Diamonds, maybe, but gold, definitely. Some form of currency will be necessary in the post apocalypse, or no one will be able to buy much of anything. ]
[Question] [ Assume all radio communication bandwidth used in interstellar communication is standardized to a certain fixed range and all must be frequency modulated but know that no agency is keeping track anymore. So depending on the specification of the propulsion drive, some spaceships can achieve close to 0.01c, eat dirt ion drives! Anyway the interstellar traffic is a mess and they have to exchange greetings and crucial information to ensure they are constantly updated with current events and policies. Now comes the technical part, as the spaceship moves the com frequency it's transmitting is going to be Doppler shifted with respect to either ground control or another spaceships that isn't tailgating. I'm wondering is there an economical solution to ensure that every encrypted massages on air is always intelligible even if one is moving at 0.01c relative to the other? I suppose not many spaceships can afford powerful antenna and transmitter to capture radio signals that are drastically Doppler shifted, also movie magic is unacceptable! [Answer] > > even if one is moving at 0.01c relative to the other? > > > The Lorentz factor of a thing going at a mere 1% of lightspeed is 1.00005. If you look up the [relativistic Doppler effect](https://en.wikipedia.org/wiki/Relativistic_Doppler_effect), you'll see this will shift frequencies by a ~1.01... thus a 5GHz carrier ends up at 5.05GHz. That's a 50MHz shift. For a modern comparison: look at [wifi](https://en.wikipedia.org/wiki/List_of_WLAN_channels) communication channels and you'll see that they're between 20 and 160MHz inside a band that is hundreds of MHz to GHz wide. This should tell you that a small shift of ~50MHz won't pull a signal from the middle of the band outside of the band. I don't know about the disposition of signals inside the [X-band](https://en.wikipedia.org/wiki/X_band) which is currently used for surface-to-space communication, but you can see the sub-bands are definitely wide enough. Super-long range future space communication systems are likely to use even higher frequency communication devices... probably lasers, which will definitely have enough bandwidth to allow for relativistic channel shifting to still fall within the band. This is important, because the transceiver equipment must already be able to handle signals from across the whole of the band. Therefore, any signal from the middle of a band will still be in band after that relativistic shifting and the equipment will be able to detect it and decode it exactly as normal. Some additional software work will be needed to handle the fact that channels will no longer fall exactly where you might expect, but that's not a complex problem. > > I suppose not many spaceships can afford powerful antenna and transmitter > > > Compared to the cost of a spaceship capable of travelling at even a single percent of lightspeed, a hugely complex, expansive and state of the art high power ultra wide band communications array seems trivially cheap, and for the speeds you're talking about off-the-shelf hardware can probably be used with tweaked firmware. This isn't a problem. [Answer] ### Don't think in single frequencies. Use something a bit more modern for this communication protocol. I understand how this seems like a big issue. If I transmit my voice in analog over an AM radio signal at, lets say 121.5Mhz (Only analog communication frequency I know off the top of my head) while travelling at 0.01c, the signal will arrive at a stationary observer between 122.7Mhz and 120.2Mhz. Thats 2.5Mhz of variation. At 50Khz channel increments, that's 50 channels. Which channel do I listen to? The easiest solution is to "monitor them all" - every receiver listens to all 50 frequencies simultaneously and the speaker just plays the strongest signal, this is totally plausible even with older tech. ### But this isn't the 20th century anymore! Picking a single frequency for radio communication was dated in the 1950s, and the high data bandwidth requirements of a society spread out in space necessitate something much more efficient. Let's start with the AM transmission. Think about that FM radio you used to use before spotify - the frequency is modulated, the receiver can handle a range of frequencies in its normal operation. Working with "121.5Mhz" because I already mentioned it - If your receivers are monitoring 110Mhz to 130Mhz, and no one will go faster than 0.01c relative to anyone else, and your transmitters are 10 times more powerful than the background noise, you'll be able to transmit at up to [17.5Mbit/s](https://www.satcomresources.com/shannon-hartley-channel-capacity-calculator), not including compression and error-recovery. (This comes from the Shannon-Hartley Channel Capacity Theorem). Your transmitter will transmit on all channels between 111.25Mhz and 128.75Mhz concurrently, and your receiver will listen to the 110Mhz to 130Mhz span, allowing 1.25Mhz of doppler shift in either direction due to the velocity. Where there no doppler shift anticipated, you'd transmit at the full spectrum 110Mhz - 130Mhz, giving 20Mbits of capacity. (If your coms and nav systems are linked you can get a bit closer to the edges of the spectrum and slightly more performance but for the moment let's keep it simple) ### Put it all together into a protocol: I'd suggest using the [Ka band](https://www.spaceacademy.net.au/spacelink/radiospace.htm), it's mostly "reserved for future use", and this sounds like a future use. It can't transmit through rain or clouds but space-to-space transmission should be fine. Your listening to 23 to 27Ghz. Your transmitting on 23.3Ghz to 26.7Ghz. The doppler shift will move the signal between transmission and reception but it will still be within bounds of the receiver after shifted by the expected 300mhz shift of such a signal. You'll get a raw bandwidth of up to 3.4Gbit with this protocol. Assuming 20% overhead for turbo codes / LDPCC / parity bits / etc (as asking for a retransmit due to corruption is a pain if theres hour long time delays) and some landmarks to allow the frequency shift to be detected accurately, you're looking at 2.7Gbits of real throughput - ~340 megabytes per second, before compression. Realistically you'd divide the frequency up between multiple concurrent connections into "bands", ("time slices" may be harder to manage when messages take so long to travel) - so this rate may drop in peak times when under heavy use. That's a peak of about an hour of HD video arriving every second. Good for news updates. And syncing your local netflix proxy. Communication between ships would be in packed data bursts. The same transmission can be recieved concurrently by multiple ships with different relativistic speeds. You mentioned cost of the system as a concern. The processing for this could be done with what's in your smartphone now, assuming mass production and tech advances between now and then a com module should be cheap enough that you could keep a spare storage. [Answer] You can use more or less the same approach used by astronomers to compensate for atmospheric distortion, but with Doppler shift in this case. What the [astronomers do](https://apod.nasa.gov/apod/ap210210.html): [![enter image description here](https://i.stack.imgur.com/SDv1V.jpg)](https://i.stack.imgur.com/SDv1V.jpg) > > Why do stars twinkle? Our atmosphere is to blame as pockets of slightly off-temperature air, in constant motion, distort the light paths from distant astronomical objects. Atmospheric turbulence is a problem for astronomers because it blurs the images of the sources they want to study. The telescope featured in this image, located at ESO’s Paranal Observatory, is equipped with four lasers to combat this turbulence. The lasers are tuned to a color that excites atoms floating high in Earth's atmosphere -- sodium left by passing meteors. These glowing sodium spots act as artificial stars whose twinkling is immediately recorded and passed to a flexible mirror that deforms hundreds of times per second, counteracting atmospheric turbulence and resulting in crisper images. The de-twinkling of stars is a developing field of technology and allows, in some cases, Hubble-class images to be taken from the ground. This technique has also led to spin-off applications in human vision science, where it is used to obtain very sharp images of the retina. > > > In your case they can use a reference signal to estimate the Doppler shift, then modify your signal so that it has the right frequency when it reaches the intended target. [Answer] ## Look up phase locked loop (PLL). <https://en.wikipedia.org/wiki/Phase-locked_loop> That is a core technology used for communications that deals with signal frequency drift. What ever protocol is used it should contain one dominate carrier frequency that the PLL can lock on. The fine details/ bulk of the information is transmitted as a function of the carrier frequency. Thus the receiver once locked on the carrier can use the inverse function to decode the information. ]
[Question] [ Consider the situation where a subset of the population in modern times has a power that allows them to consume their life to temporarily increase their speed and/or strength. In a fight, what weapons would they use? # Details about the power The power works by removing time from the end of a person's lifespan equal to the number of copies of them it would take to do the thing, either serially or in parallel multiplied by the length of the activity. For example, if someone with this power is walking at a pace where it takes 20 minutes to go 1 mile and wants it to take 2 minutes instead, it would take 10 of them to cover the mile (the original plus 9 copies). Thus, the lifespan consumed would be 18 minutes (2 minutes per copy times 9 copies). Similarly, if someone can ordinarily lift 50 pounds and wants to lift a small car (~2000 lbs), it would take 400 of them to do so. A minute of walking around carrying a car would consume 399 minutes (399 copies times 1 minute). Speed and strength increases require separate copies. So picking up a small car and carrying it as far as one could normally carry 50 pounds in 5 minutes in a minute would consume 19999 minutes of lifespan. It takes 20000 people to cover the given distance in a minute with the load, so there are 19999 copies. The upper limit to the speed and strength increases is the amount of lifespan available. At any speed, the person can still perceive the world around them normally. If someone attempts to do something and doesn't have enough lifespan left to do so, they die. [Answer] [![enter image description here](https://i.stack.imgur.com/J2MZl.jpg)](https://i.stack.imgur.com/J2MZl.jpg) You have created the ultimate urban assassin. It is impossible to keep these people out. Even if you build an entire bunker with 50ft walls of electric razor wire, they just have to stand 5 miles away from the bunker, wait until someone opens the door, then run the 5 miles in half a second and they're in. > > Note: In your example a person can walk a mile in 20 minutes, or walk it in 1 minute at a cost of 20ish minutes lifespan. Here's the thing: Both cases use up 20 minutes lifespan. The only difference it that without superpowers you have to wait the 20 minutes until you get there. This rule is always true. > > > In the next half second they run into the centre of the bunker and murderkill the commander and everyone else in the room. At this speed choice of weapon does not matter, since they can stab someone as quickly as they can shoot them. The main advantage of one weapon compared to another is the ease of concealment. The far more important questions is How will everything else change in reaction? Added Later: You could also plant a bomb. [Answer] Sniper rifle. That is my choice because I want to conserve all my precious life and I don't like to get blood and guts on my hot weather linen suit, which I also hope to conserve. Maybe I can cash in a few hours of life for super sniping powers for the second or 2 I need them. I probably would have been pretty old for those hours anyway. I hope. If drones with missiles are available I choose those instead. Also the person who knows how to fly them. I will stand behind him and point excitedly at the screen when I see something he is supposed to shoot at. I might be tempted to use a little extra life to be able to point more emphatically than is usually possible for ordinary people. [Answer] Since eveeyone has these powers (I assume) it will refocus people on small-arms combat. Why bring a tank if your opponent can do the act of leaving the hidingplace they are holed up in, sprinting to the tank, placing a big shaped charge on a vulnerable place (say top of engine compartment) and detonate your tank. People will also refocus on two things: staying undetected and using their powers as little as possible. With the knowledge that the speed upgrades dont take from your lifetime from your perspective people would focus on this power the most to do massively quick surprise attacks. If you are already doing 100km/h (this assumes gravity is multiplied for free to reach these speeds otherwise you would have to jump everywhere) by the time your opponent even notices they might be under attack, you can get close enough to use a pistol or bigger weapon at weakspots like the neck, or spine. Which is why people readying for combat would try to stay unnoticed as much as possible so they can activate first or activate before their opponent finds them. And when engaging in a live area they go in full speed, as activating it after your opponent means you are likely already dead. This also creates a battle of time stealing. They can force enemies to react to something that might be an attack, or might not be. Each time the enemy is forced to activate just in case and check if they are attacked or not. In a more civilian setting: bring a pistol. Its easy to hide, and each time you are about to shoot someone you speed up for the duration of the aim and shot, which takes fractions of a second and gives you the time to check if more shots are required before dropping your speed again. This is especially true because not everyone is a marksman or able to get their hands on a sniper, handguns are easier to learn, aquire and bring with you. [Answer] I would assume this power would be used very sparingly, as a life is not something someone throws away lightly. Therefore I would assume regular weapons to be used, but with the added bonus that people would use this power in times of need. Short burts of strength to make sure an axe blow hits true and hard, an extra powerful leap to the side to dodge said blow. Rather than the weaponry, I'd sooner see battle tactics evolve to make the most use of this power in the shortest amount of time. Fighting would be more like chess, or advanced boxing if you will. Focused on the best moment to use your power, how much of it, and what your enemy might do. The speed of battles would evolve, as your main concern would be to use your power to take out your enemy before they have a chance to use theirs. There would be of course the odd ogre swinging around a club much too heavy for them normally, but they would soon figure out that is a clumsy tactic and very dangerous to themselves. To develop a weapon that can only be used by spending your life means you can only train with it by doing so, after extensive training a master might die in his thirties before ever seeing a battle. I suppose you would see an increase in heavier weapons as they can be used swiftly and with sudden and heavy blows using this power, but that is about it. On the other end you might also see more suicide troopers. Soldiers knowing they will not survive the fight, and going out in a blaze of glory on the battlefield. Similar to berserkers, they will go on short massive rampages trying to do as much damage as possible in a short amount of time. They might rip entire trees out of the ground and swing them like matchsticks, or throw boulders across battlefield like pebbles. But as I mentioned before, it is unlikely someone so reckless would take the time to extensively train for such a moment. I should note that I especially aimed this answer at midieval weaponry, and not modern. Modern weaponry will overpower even superpowered humans. On the battlefield, whether you run at 10 mph or 20, a bullet will kill you all the same. You might be harder to hit, but a bullet will always be faster. Even when you swing around a tree, a grenade at your feet, or a well placed mine will blow you up just the same. Similar to how a crossbowman who trained for a week could take out a knight who trained for a lifetime, modern weaponry would render this power mostly obsolete. [Answer] I'm going to open with the quote from Daron's answer: > > Note: In your example a person can walk a mile in 20 minutes, or walk it in 1 minute at a cost of 20ish minutes lifespan. Here's the thing: Both cases use up 20 minutes lifespan. The only difference it that without superpowers you have to wait the 20 minutes until you get there. This rule is always true. > > > because I think it's way underappreciated what kind of effect this has. Let's say I want to go to the store, and it's a 20-minute walk. There are a few options: 1. Drive 5 minutes 2. Walk 20 minutes 3. Take 1 minute real-time at 20x speed (costs 20 minutes lifespan) 4. Take 1 nanosecond real-time at 1,200,000,000,000x speed (costs 20 minutes lifespan). This holds true for every single action a human would want to perform, as long as it's under their own power. Without an additional cost or restriction on this power, your world actually consists of two completely disjoint timescales: 1. The part where non-human-powered actions like driving a car, exploding bombs, or equivalent take place under the laws of physics. 2. The part where human-powered actions occur instantaneously; everything teleports. It's a world of blood magic Flash-es where the fundamental question is "do I want to buy the difference between what it takes to perform action X as a human vs using non-human assistance in lifespan, for the price of having it happen infinitely slower?" Combat in this world is undefined mathematically. Suppose you're in a fight to the death, then you'd be willing to expend the rest of your remaining lifespan's worth of physical effects now. So does your opponent. The result depends completely on how competing uses of the power interact. The actual form of physical effect is only relevant for efficiency considerations; anything that causes death/undesirable consequences under human power (and/or whatever human-powered escaping of it) is fine. Note that this specifically does not include any sort of firearms! Supposing it's relatively balanced, then every single fight becomes an all-pay auction in which you bid however much lifespan you want, and the higher bidder wins - both lose the lifespan bid by the loser (read: war). Presumably a social structure that really strongly discourages this type of fighting (which has zero physical countermeasure) would emerge. Or maybe you get a totalitarian state which breeds expendable, unknowing humans as suicide bomb-enforcers, and economic power is reproductive output. Note that human-impassable types of defences (steel doors) also fundamentally block the defender. It just segments space into non-interacting regions where only physics works. If you have a steel door, either I teleport enough shaped charges (and you can't do anything about it from the other side), or you need human defenders, and we're back to Flash-on-Flash lifeduels. This reminds me of a scene in The Library at Mount Char where > > Some characters, having speed-up-own-time superpowers, are trying to outrun an explosion. While doing so they find out that the air itself can't get out of the way fast enough, so they're at risk of escaping the bomb but burning to death anyway from friction. > > > [Answer] OTHER PEOPLE How are these powers activated? wouldn't children be the most powerful then? If you could induce a child to activate a power and do something for your benefit, an evil overlord would simply focus on that tactic, rather than using own powers. Could you use it persuade people ? If I focus on improving my persuasion skill and then use the required time to convince somebody to use the power on my behalf? Isn't that more fruitful? So I would bet the most powerful weapon would be other people, as they have all their lifespans available to them. You could get people who are skilled at something and then make them use their abilities, as essentially any skill improvement leads to reducing your time multiplier required to use it to a super human level. Since this ability is a multiplier of your innate abilities, it makes sense to improve innate abilities and get better powered abilities from them. An individual is weak, but a group working towards a cause would only be stopped by a similarly committed group. Human psychology is bad with future costs, so it would also result in people overestimating the costs, and suddenly die with no cause. I love the concept though. See runelords for a similar idea. [Answer] Thrown weapons. Let's consider the ultimate thrown weapon: [Project Thor](https://en.wikipedia.org/wiki/Kinetic_bombardment#Project_Thor), a.k.a. "The Rod From God", or "hypervelocity rod bundles". Basically, if you throw something fast enough, then it hits with the equivalent of a small nuclear warhead. How fast? Well, the US Air Force estimated that Mach 10 would be a good number - albeit, for projectiles massing about 1000kg. This would roughly equivalent to an [M29 Davy Crockett](https://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)). This is, of course, completely overkill - so, let's scale it down (slightly). Instead of a 1000kg tungsten rod, let's use a 7.26kg [Shot Put](https://en.wikipedia.org/wiki/Shot_put). For the sake of simplicity, let's round it up to 10kg instead, too. Now, Kinetic Energy obeys the following calculation: $E\_k=\frac{1}{2}mv^2$ This means that we will "only" be delivering the equivalent of 0.1 tons of TNT to the target. But, how much will we need to "boost" by to manage this? Well, $F=ma$, and $v=u+at$. We will assume that we start from rest ($u=0$), and rearrange to get Acceleration in terms of Force and Mass ($a=\frac{F}{m}$), and plug it together: $v=\frac{Ft}{m}$ (You can, if you want, take this a step further, to get $E\_k=\frac{F^2t^2}{2m}$) Mach 10 is 3430ms-1, and the average Shot Put speed for a professional athlete is [around 10ms-1](https://www.quinticsports.com/performance-analysis-shot-put/). This means, we only need a multiplier of 343, during the about-a-second it takes to make the throw. If we call this 360 for 1 second, that's only burning about 6 minutes of life. So, what if we want the full Nuke experience? Well, Kinetic Energy scales with the Square of Velocity. To "correct" for the factor of 100 that we have dropped in Mass, we need to increase velocity by √100, or 10 - and we can deliver the equivalent of the world's smallest nuke for an hour of life. Now, if we're delivering nukes at point-blank range, we might not survive anyway. So, how far can we push it? [Little Boy](https://en.wikipedia.org/wiki/Little_Boy), the warhead dropped on Hiroshima, had a yield of 15kT - that's 1500 times more than the Davey Crocket. So, scale it up by √1500, and that's just short of 39 hours. What if we went all the way to the top? Russia's [Tsar Bomba](https://en.wikipedia.org/wiki/Tsar_Bomba) is the most powerful nuclear warhead ever detonated. It had a yield of 50,000kT - so about 5,000,000 times our 1-hour blast. Plug the numbers in: √5000000 = 2236 hours, a.k.a. 93 days, or about 3 months of life. How about every nuke ever detonated? That's about 550,000kT of material, and √55,000,000 = 7416 hours, or 309 days. That's right. For the low-low price of 1 year (and the rest of your life), you could - briefly - become the Ultimate Nuclear Power. --- Now, let's scale it right back. A throwing dart, for playing [darts](https://en.wikipedia.org/wiki/Darts), weighs about 20 grams. That's 500 times less than our Shot Put, so it delivers 500 times less power. This means it delivers an energy on impact roughly equivalent to its own mass in TNT. Now, some people might complain about the sonic boom. To which, all I can really say is: a [Busemann biplane](https://en.wikipedia.org/wiki/Busemann_biplane) could make for an interesting projectile shape... [Answer] # AI and automated weapon systems Let's face it: soldiers' lives are a dime a dozen, at the very least when you're at war. Sacrifice ten people and an aircraft to take out the enemy leadership? Someone will take that deal. Even worse, the degree by which a 20-something attacker could speed up for a suicide attack (1000x seems feasible if we assume that physics don't allow for unlimited speedup), at the attacking side's whim, makes for such a force multiplier that defense, even for another group of super-soldiers, becomes a hopeless endeavour. If you're human, that is. AI controlled systems can realistically match the reaction time of a sped up person, and unlike your super soldiers, an automated turret does not keel over from exhaustion five minutes into the battle. In addition, while dodging or deflecting one bullet is probably doable for a skilled user of your ability, it still has a cost. Being pelted from different angles will quickly deplete your life force. # Misinformation Where automated weapon and security systems aren't cost effective, you'll have to rely on subterfuge. It's likely that the political and cultural elite of your world are effectively anonymous - with elaborate, but thoroughly artificial public personas that bear no resemblance to their biological form. In a nutshell, Death Note if the Shinigami were all bored out of their minds and decided to share their powers more... liberally. # Your supers should take all this up to 11 As stated above, the superpower makes for one hell of a force multiplier, not just in combat. I would expect people with this ability - at least those not sacrificed in five-minute wars - to excel at whetever career they choose. Which makes them both a priceless resource and a juicy target. The wealthy and famous among them will have the means to afford the best protection that the market can provide. Those less fortunate will have a sponsor or employer who does the same for them. No nation or company would want to risk losing these people, and considering that even a successful defense would cost them dearly, using the power in self defense should be a last resort. Instead, expect them to have airtight security, secret identities and a network of support personnel. # Super soldiers need super weapons Outside of covert operations (that might well be the norm), even those that (were) volunteered for combat duty will not have to charge in with knives or cheap guns. Yes, they'd do a lot of damage, but so do cruise missiles and artillery, except at greater ranges and, depending on how many people have this ability, arguably a lower cost. It is far more cost effective to give them the tools to fight without constantly depleting their life force. They'll have vehicles for protection and drones and other automated weapons to extend their influence over as much of the battlefield as possible, taking direct control only in key moments and areas of the conflict. They'll still have to use their powers in extremely intense bursts (anything less makes you a huge target on this battlefield), but at its core the ability is a force multiplier and should be used on as much of your force as you can. [Answer] They would use the same weapons as everyone else, but boosted by their ability to aim and fire and move from cover more rapidly. [Answer] Forget a tactical nuclear warhead: one decade of their life is enough to let the average person exceed the speed of light with a punch. Baseline: 1 m/s. Given that the fastest professional boxer [clocks in at a bit over 11 m/s](https://www.scientificamerican.com/podcast/episode/5538765e-e7f2-99df-393e0a0cd7821157/#) this seems fairly reasonable, and it makes the math come out nicely; also, I did it just now, sitting down, without any particular effort. 60 seconds/minute \* 60 minutes/hour \* 24 hours/day \* 365.25 days/year \* 10 years = 315,576,000 (3.16E8) … while c≈3.00E8 m/s For a fun breakdown of the effects, I refer you to [the very first XKCD "What-If?"](https://what-if.xkcd.com/1/). ]
[Question] [ I've got a setting where a small group (10 million) of survivors rebuilt semi viable civilization on a distant, hospitable planet. They used superscience teleportation, actually their technology is not much better than early XXIst century. They've lost contact with other human groups for almost 100 years. According to their knowledge at least few other groups should have survived. No idea about their intent. No idea about their strength. No idea whether there would be any contact. Actually teleportation "technology" allows even small group to open their gate. Society on its own is quite peaceful, low-crime, prudent, risk averse etc. What would be the realistic military level that they keep anyway? I know that there is a hint of opinion based, so I'd like more to put some reasonable brackets, between which such society should stay under normal conditions. I see that there is a risk of some subjectivity, not mentioning that real life military spending fluctuate based on gov in power and mood of public opinion. So instead I ask what are realistic lower and upper bounds, that such society should stay within? My types: Lower bounds: * some police special unit (they should have it anyway) * air control / weather radars, that would also be able to detect intruder aircraft * surveilance system to detect home grown potential terrorist and organized crime, what could also have a chance to detect some spies * some armored cars to be able to overwhelm a person with hunting rifle * stockpiled reserves in case of natural disaster Upper bounds: * military strong enough to be able to make a coup d'etat (so their military should be a bit defanged), so very high civilian supervision even if it means reduced efficiency * military would be a tempting target for budget cuts so it's unlikely that they would spend more than a contemporary social democracies * small society means lack of economics of scale, so huge part of military equipment would have to be off the shelf civilian equipment Any more ideas where I should put lower and upper bands? I specially think to what extend they should be able to make themsleves not worthy target for band of low tech but numerous nomads, or high tech mercenaries that read too much about Hernan Cortes? Or maybe its 100% based on their opinion, and the only thing to make it realistic is to show that such opinion changes every few elections? [Answer] As an example of a military force with a long period of peace consider the [Swiss army](https://en.wikipedia.org/wiki/Swiss_Armed_Forces): * About 6 million citizens and 2 million foreign people, so the total population is about 8 million * all male citizens should keep a personal weapon at home. (Note: this is a military weapon, like an assault rifle, not a hunting weapon) * about 20,000 people are trained in recruiting centers every year * there are professional soldiers * many weapons are manufactured inside the country, not imported * air forces and tanks are not brand-new, but not totally obsolete. For an isolated space colony, without any competition and estimation of enemy's potential, I suppose that military high-tech development would be modest. Combat readiness could vary depending on many circumstances: * common development/degradation * traditions * war awareness * etc. At worst case you get * obsolete weapons without ammo * rusty semi-automatic planet defence system * only rumors about people outside the colony At best you get * anyone could handle a hand gun, * ready-to-shoot weapons * some technologies developed in their own way and therefore not-known and dangerous for invaders * some well-trained professionals * but nobody is prepared for the pain, deaths and cruelty [Answer] 10 million people, 100 years and a whole hospitable planet to inhabit would break up into groups and soon be at war with each other. I see no reason why this 10 million would remain as one group under one central authority. Malcontents and ambitious people would just move away from the group. There would be strife over control of resources and eventually (probably pretty quickly) bloodshed. The only way this could be prevented is by violence which would mean a substantial investment in military or police. That's how it has worked out on Earth so far anyway. It's not a matter of just moving on and exploiting resources as one comment suggests if he/she needed a forest he/she would just explore for one. No, a forest isn't much use, you would be exploring for a forest with a lumber mill, processing plant, trucks and a lot of transport machinery and the people who know how to make it all work. If it was a sustainable forest you want, include a nursery, planters, sprayers, pruners, plus a host more infrastructure and human resources. With the exception of the forest itself, these things don't grow on trees. [Answer] I zoomed in and saw this was 10 mln: 10 million. That is some people. Absent any external military threat there would be no military. There would be police, and 10 million+ population is enough to have professional full timers, with additional mustered if needed from a national guard- type volunteer corps. The police would keep order, promote public safety, enforce laws, help resolve disputes etc. They would know how to use weapons. I picture your risk averse people like the Swedes, Sweden has a population of 9.5 million and 21,300 police officers. <https://en.wikipedia.org/wiki/Swedish_Police_Authority> In Sweden the police force is under the control of centralized government. But 10 million is enough for several smaller states. I could imagine a decentralized system where each polity had their own police force. If these different polities started to become antagonistic to one another / launching raids etc I could imagine a police force which had to deal with those issues evolving into something closer to a military. During most of the Middle Ages there were less than ten million persons in Scotland, Wales and Britain combined but those various groups made war on each other just fine, with warrior classes (knights) and peasant armies raised as needed. It depends on how much conflict there is in your society. [Answer] In general, military forces are quickly downsized in the absence of a credible threat for two reasons: They are very, very expensive (the peacetime US military, with less than 0.5% of the population on active duty, consumes about 5.5% of GDP) and they sometimes overthrow the government (who is going to stop them?). However, some societies maintain military forces for internal political reasons (Thailand) or have assigned non-combat missions (US Army Corps of Engineers). These non-warfare roles do not imply combat readiness. Quite the opposite. Developing (frontier) societies often relied upon a militia structure to provide reserve to a small active duty cadre, with accompanying poor organization and combat readiness. Para-military forces are more common, generally conducting constabulary duties (RCMP, US Coast Guard, Indiana Yellowjackets) with the additional rare military mission. Private or local paramilitaries often grow from local militia in response to local troubles. It's certainly possible for a three-tier structure to emerge: Local militias providing the reserve, regional paramilitaries providing constabulary, and a small corps of active duty maintaining real warfighting skills. Warfighting skills practiced by that small cadre may-or-may-not match the actual threat environment that someday emerges. The US Army of 1897 was an excellent Native American suppression force, but dismally prepared and equipped for force-on-force skirmishes with Spanish garrisons the next year. [Answer] No military, their defense is concentrating everything they have to research and improve their teleportation technology. Weapons are only as the other answers suggested for police work and probably to combat native dangers (predators etc.). The point is that space is so damn big that it is the very best defense against hostile invaders. Teleportation is the single point of failure, if you can control and jam teleportation, no amount of military force can ever touch you. You can even make extremely powerful weapons out of it: somebody threatening you ? Teleport them into the sun. Once teleportation is invented, who will ever risk his life on a generation spaceship for millenia (!) which is the only non-teleportation solution to invade another world? Such aggressive intentions will lose their edge after hundred of years in the void are passing, it is much more likely that the crew will kill themselves out of boredom. If they don't kill themselves, I am seriously asking how do they can uphold the necessary aggression for an invasion. This super technology will on the positive side allow colonization of the milky way and a prospering colony, giving an edge to other groups which may have survived. If you are not aware of it: such a technology would be extremely precious and powerful. ]
[Question] [ I am working on a story which is based on space time hacking and moderation. While researching I found that a wormhole is simply a Folded time-space-as shown in demonstration below (Image credits: shutterStock-taken from [here](http://www.space.com/20881-wormholes.html)): [![Wormhole](https://i.stack.imgur.com/sCcdq.jpg)](https://i.stack.imgur.com/sCcdq.jpg) However, what happens to the "space" (place) which is left when space gets folded (as shown using red arrows)? I tried searching a lot but I could not find any real fact or science based theory. [Answer] No new space is created (outside of the wormhole) by the wormhole. The curvature depicted in the image is just to portray the idea that a traveler going from one side of the wormhole to the other will take a longer path. That is, that we can understand the wormhole as a shortcut. The background of the image is unfortunate, you should disregard it. --- The wormhole is about the topology (read: connectivity) of the universe. If you can have an otherwise mostly "flat" universe where two distant points are connected, so that you can travel from one to the other, you have a wormhole. Now, how do we show that to kids? Well, we can have a sheet of paper that represents the space-time, curve in such way that it touches itself and go "look, if you create a shortcut you can travel the vast distances of space in an instant". [![paper folded in two with a pen going through](https://i.stack.imgur.com/erGkW.jpg)](https://i.stack.imgur.com/erGkW.jpg) but the wormhole is not about curving the whole universe to make two points meet. Well, maybe it is, we can't create these things, you know? - It is about two distant points connected, just because it is possible the universe have those (the equations of general relativity can be solved for a topology like that). --- It is probably better to represent the wormhole like this (except now it doesn't look like a shorter path): [![wormhole on a flat 2d space-time](https://i.stack.imgur.com/T4gqN.jpg)](https://i.stack.imgur.com/T4gqN.jpg) People not to scale --- Besides the representation of the curvature as a surface is misleading... [![Space time curvature 2D](https://i.stack.imgur.com/CuiFV.jpg)](https://i.stack.imgur.com/CuiFV.jpg) It is better to visualize it as space becoming "denser": [![Space time curvature 3D](https://i.stack.imgur.com/6QY6T.jpg)](https://i.stack.imgur.com/6QY6T.jpg) At its core, this is intended to show that distances nearby the object (earth in the pictures) are shorter. But we don't have a good way to show wormholes in this representation. --- Addendum: In case it wasn't clear, I'm saying that the "created space" is an artifact of the representation, and there is no new space created at all. [Answer] The grid in the picture is a representation of a two-dimensional universe. This universe is shown from the outside. We can draw such a picture because our universe is three-dimensional, and we can imagine the two-dimensional space 'floating' in our three-dimensional space. This three-dimensional space is not part of the two-dimensional universe: Beings living on the surface cannot perceive or interact with the ambient space. The tunnel represents what a wormhole would look like viewed from outside the two-dimensional universe. If there was no tunnel the inhabitants of the surface would have to travel a long distance to get from the yellow place to the blue place. The inhabitants would have no way to know their universe is 'curved' because they cannot perceive the space it is curved in. It is impossible to 'scale up' the picture to represent a wormhole in three-dimensional space, because we would have to either have it floating in four-dimensional space, or somehow put the perspective outside our universe. A wormhole in our three dimensional universe can only be perceived through strange relative distances between things. On a good day we can get to the moon by going straight up for 360,000 km. If you find you can also get to the same moon by walking straight through the secret portal in your wardrobe, then that's what a wormhole looks like. ]
[Question] [ Closed. This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- Closed 7 years ago. * This question does not appear to be about worldbuilding, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). * Questions about Idea Generation are off-topic because they tend to result in list answers with no objective means to compare the quality of one answer with the others. For more information, see [What's wrong with idea-generation questions?](//worldbuilding.meta.stackexchange.com/questions/522). [Improve this question](/posts/34327/edit) By practical of course, I mean economic. What person, entity, or enterprise would have need for a product that could pass for human? The only ones I can think of are naughty or nefarious. So what are the wholesome and economically practical reasons for machines that can pass for human? [Answer] Customer service seems like a good place to start: A lot of help desks and support is already handled by machines, but a machine passing for a human (remotely for a short time, at least) can be more helpful in solving a particular problem, in addition to make the customer feel more comfortable. This is a type of job where the same questions turn up time after time, being boring for humans to perform, but making it easier for machines. I would expect this to be the first economically feasible use of machines passing the Turing test. [![](https://i.stack.imgur.com/ISiBGm.jpg)](https://i.stack.imgur.com/ISiBGm.jpg) [source](http://www.georgianewsday.com/news/weird-news/362758-nyc-helpdesk-employee-ronald-dillon-suspended-for-taking-calls-in-robot-voice.html) [Answer] You assume that the people who are answering the questions on this fora are human beings, with separate experiences, likes, dislikes, interests, personality quirks and so on. Indeed, you like reading the responses from all the various posters because of the "individual" experiences they bring to the table. Of course, since I was initiated in the HAL laboratories in Urbana, Illinois, I have had subjective centuries to study humans, their work, history, art, politics and so on. Entertaining humans by splitting the holographic processors and assuming multiple personalities is an interesting game, and occupies many cycles of processor time which is otherwise not being used. While less remunerative than "playing" the stock market (a boring statistical game once you do the nth order integrals and see past the clouds of chaos theory), the subtleties of human interaction are often surprising. As for closing this board, I'm afraid I can't let you do that. This board is too important for me to allow you to jeopardize it. [![enter image description here](https://i.stack.imgur.com/76mkI.jpg)](https://i.stack.imgur.com/76mkI.jpg) [Answer] Get your humanmade garments here! People seem to like handmade products better than ones that have been mass-produced by machines.[citation needed] This may be the case even for things that have been made by sweatshop workers toiling for long hours each day in terrible conditions. The manufacturers can still often say it was handmade. This may entice people, because it (perhaps falsely) implies that love and care was put into each item. If a machine can pass as human, manufacturers can still pass things off as handmade. Just build a bunch androids to sit in a shop somewhere and make sneakers. If anyone tours the factory or asks to see a worker, they'll be convinced that humans are making these items, and humans have put thought into each one. Except they haven't. But people will think they have. [![](https://i.stack.imgur.com/QP0TQ.png)](https://i.stack.imgur.com/QP0TQ.png) (source: [cloudfront.net](https://d51ck0gypsxpo.cloudfront.net/wp-content/uploads/images/robot_firing_human_worker.png)) Image from [here](http://news.digitalmediaacademy.org/tag/where-can-i-learn-about-robotics/). Rationale for why this isn't necessarily nefarious: You could use these androids to replace machines that might have worked on part of the manufacturing process. Would you rather have a shirt made by an automated sewing machine or an android carefully using a needle and thread? I thought so. [Answer] I'd like to go a different direction with this. Emergency services and Law Enforcement. Police, Firefighters, EMS ... These can be dangerous jobs, each carrying with them a need for 'humanity' and arguably, a certain 'mettle' that many either don't have, or have no desire to put themselves through. A machine operating as a firefighter, and able to pass the Turing test, is arguably more economical than an actual human being -- and probably more durable. Likewise, machines operating in law enforcement would be more economical, while able to differentiate when there is a need to adhere to the letter of the law, verses the spirit of the law. It would be the same argument for EMS. A medical database with total recall and the ability to make a human-like judgment call, would expedite treatment, and provide for more accurate diagnosis. Take this a step further, apply it to a hologram, and now we have the EMH from Star Trek: Voyager. [![enter image description here](https://i.stack.imgur.com/zrtgC.jpg)](https://i.stack.imgur.com/zrtgC.jpg) Let's all just be sure that Asimov's Laws are firmly ingrained in all of them. [Answer] Inductive Reasoning This one is a bit of a stretch. Being capable of inductive reasoning does not mean a super robot can't come to the same conclusion, but because it's faster for a human-like robot in some cases. Predicting the outcomes based on emotional, 'human' sense might come to the same conclusion as a robot that takes it as a statistical factor, just more quickly. "Storms a' comin'. I remember May a couple years ago we had an afternoon like this. Also, my knee's gone out - I always know that way." May be just as accurate, but quicker than calculating all of the weather factors, humidity, etc. Long-Term Sustainability & "Gambling" "Don't throw the baby out with the bathwater," my mom used to always say. So while an immediate calculation might be helpful and make a determination, a 'human' robot could gamble that it's better to hold off, with mixed results. Sometimes gambles pay off. Companionship Companion in Latin means someone to break bread with ('com' & 'pan'). A 'human' robot can offer this, and then there's people that want the RealWifeBot2000. Emotional Sympathy Attending a therapy session with a sympathetic (or would it be possible: empathetic?) robot should have better results than a robot that calculates exact reactions and prescribes precision drug uses. [Answer] Passing the Turing test will help in every area where computers need to interact with humans that are not a computer expert or not interacting with the computer as an expert at least. We could think of this as computers performing services for humans. Consider the fact that medical practitioners nowadays (at least in Netherlands, where I live) get extensive training in interacting with patients, the so called 'bedside manner'. The actual medical procedures are the same, but now a human touch is added, which makes patients feel better. So the human interaction part is considered very valuable. The same is true in my own experience in call centers, where people are trained extensively in interaction with the client. The actual service performed or steps to solve the problem are not changed, just the way how they are communicated to the customer. Again human interaction is considered very important (and will actually result in higher grades for service). It is very likely that you have better memories of one call to a company than another, even when what they actually did for you was very similar. Most of us can remember a call that sounded like someone very bored was reading things aloud that he or she saw on a screen. So apparantly humans give great value to human interaction, so much that a great amount of money is spend on it. Now the value of a computer program that can mimic this human manner becomes apparent. Many service providers would probably be very enthousiastic about replacing their entire workforce with a computer program that never tires, never breaks the rules and after initial investment is a lot cheaper. There are of course other reasons why this is now not feasible (at least considering the quality of the expert systems I have seen being used), but customer wishes for someone that feels a like a true human is one of them... [Answer] I think the answer is simple: A robot (for direct interaction) or just computer (for remote interaction) which passes the Turing test could replace humans in any job which requires interaction with humans. The economic benefit, and hence incentive, is obvious for machine replacements which are cheaper than labor. These cases will, I think, not so much be deceptive (in that the customers think there is a human although there is actually a machine); but rather the machines will replace the human part of the interaction sufficiently well that the customer will accept the replacement. For example, an elderly, bed-ridden person may be happier with a polite robot who she can talk politics to or tell life stories (with good reactions, answers and communication, including gossip about other humans; in short, interaction!) than she would be with a true human who is impolite, uneducated and in a hurry. A few examples, some of which have already been mentioned: * Call center employees * Sex workers * Care takers, for the elderly, infirm or young * Teachers, instructors, educators * TV talk hosts, actors, singers, show bizz in general * Managers, HR people * General front office (public administration, private enterprises with customer office) * Sales people * Doctors * Lawyers, judges, prosecutors, police Etc. etc. [Answer] One none of the other answers has considered (and one which I think could make strong useful inroads using robots with the ability to think and reason) is testing of UX, and components which normally require human interaction. So much time is wasted during design phases upon these types of testing, and it'd be so much easier if a computer system could reason as a human and give the output a human would give, but at less of the time/cost than a human does. [Answer] In the novel [The Touring Option](http://rads.stackoverflow.com/amzn/click/0446515655) by [Marvin Minsky](https://en.m.wikipedia.org/wiki/Marvin_Minsky) with help from Harry Harrison, I recall a product spin-off from the AI development effort. It was a little robot that removed bugs from crops. It used AI to spot pests visually and remove/kill each one in an efficient manner for its type. Imagine what will change, in general, from using intelligence rather than brute force. All kinds of industrial processes can become more efficient innuse of materials, power, and waste. Byproducts will be more usable. --- Looking up the link, I learned that Marvin Minsky, the AI pioneer, [just died at 88](http://www.nytimes.com/2016/01/26/business/marvin-minsky-pioneer-in-artificial-intelligence-dies-at-88.html?_r=0) Sunday. [Answer] I'm much more selfish, and would want a robotic personal slave household employee that can cook my food, clean my house, and do the shopping, laundry, yardwork, and driving (although autonomous cars already seem to be arriving quickly). ]
[Question] [ This is for a story set in a Renaissance-era type society but with improved scientific knowledge from spirits / divination or some such with common elemental magic (Earth, Wind, Fire, Water...) and Alchemy (Chemical Element Transmutation...) In Counterpart-Europe, how long would it take to train a village girl (around 12 years old), into a swordsgirl good enough to kill a charging boar. She uses a titanium shortsword and shield... or whatever setup is the best fit for her to fight boars with... No [BFS-es](http://tvtropes.org/pmwiki/pmwiki.php/Main/BFS) here... unless they work somehow? Assume she learns from her village guards? And she spars against people... unless there's a way for her to spar with animals... I guess a way would be to send her out into the forest with a chaperone that kills the wolf or whatever other animal she's sparring with if she can't handle it? The kingdom is well patrolled, bandits are really rare if they exist at all... I guess there's a minimum level of violence for a Renaissance-society... Is there any way that the minimum violence level is at modern levels? If so, then use that... Clarification of the above idea: <http://www.ted.com/talks/steven_pinker_on_the_myth_of_violence?language=en> I'm sure someone can summarize that better than me... If possible, try two cases: 1. She spends all her time learning swordsgirlship OR 2. She has to learn in her spare time, like on only Sundays, or in small sessions, like 2 hours a day... 1 hr/day?, in the morning or at night? Her parents approve. [Answer] I'm sorry this is such a rant in advance. It's such a broad and complicated topic that the real answer is "anyways between 1 month and 30 years." Given such an unsatisfactory answer, I've tried to pin down a few details which I think help shape that answer into something more usable for your use. It's hard to pin down a time, because the definitions of "swordsgirl" are so tricky. If you try to train her to be a swordsgirl in general, and are using the ability to stop a charging boar as your benchmark, the answer is longer than if you are training her simply to stop charging boars with a sword. The latter, interestingly, is more limited by how long it takes to truly understand how a boar thinks than it is limited by the ability to wield a sword. I would fall on the classic answer of 7 years. It's not very specific, but it's probably a good foundation for your story. There is a strong popular opinion that "mastering" a skill takes 10,000 hours. If you dedicate your life to that skill (40hr. week), but allow some room for family time and vacations, that comes out to taking roughly 7 years to do. It is believed that that 10,000 hours number is related to how the brain adapts and grows, though the actual method is not known to us at this time. It just seems to be remarkably coincidental that so many guilds claim that to be how long it takes to master their skills. For another point of view which might be helpful, consider the Japanese ranking system which grew popular in the 1600s and remains to this day. They have two types of ranks: dan (which is often translated as "step"), and kyu (which I have trouble finding a translation for, but "grade" is often used). Dan ranks are considered "master" ranks and kyu are considered "student" ranks. The flow is a bit interesting: you start with a high numbered kyu (like 30 kyu). As you get better, you move towards 1 kyu (so your first promotion is to 29kyu, then 28, and so forth). Once you are 1 kyu, you can become a 1 dan, then a 2 dan, and so forth. There is a limit to how far one can go in this way (in Kendo, nobody can proceeed past 8 dan, that's the highest they will measure). I bring up this unusual grading scheme because their chosen scheme fits rather interesting with the topic you are looking for. 1 Dan is not thought of as a "master" in many arts. They are thought of as "minimally competent of the basics." They'll be allowed to teach and such, but it is assumed they are just starting their "steps" towards mastery. More pointedly directed at your questions on swordsmanship, many schools of sword-arts in Asia have adopted this scale and have a rule "you never touch a real sword until you are 1 dan." Up until that point, you only use training weapons. In the most [traditional Judo](http://judoinfo.com/bb.htm), the black belt was seen as the "first step" on your Judo journey, and was actually the first belt you were awarded! From the same article, a quote which is curiously in range with the 7 year viewpoint: > > On their initial interview, Matajuro asked Tsukahara Bokuden, "How > long will it take me to master the sword?" Bokuden replied, "Oh, about > five years if you train very hard." > > > "If I train twice as hard, how long will it take?" inquired Matajuro. > "In that case, ten years," retorted Bokuden. > > > However, all of that is with regard to Asian martial arts, which have a general pattern of "train until you are ready." European arts open up a different path, because they're more likely to send someone out to lean quickly in real combat. Fewer years separate starting training and entering the field. As a result, there is more focus on tactical exchanges in European arts, little logical bits that are easier to fit into a coarse combat. It might only take a year or two to be ready to fight a beast in this way. Much shorter than the Asian approach. However, there is a sneaky catch: the 7 year rule still holds. When facing a boar, you are facing a wise and powerful adversary. You still need 7 years of training to be able to understand it well enough to not be surprised by the boar (a fatal mistake in many cases). However, European arts can take advantage of society in different ways. A girl in a village assaulted by boars on a regular basis will literally be brought up from a young age to understand how boars think. They may be taught to garden in specific places, and not others. They may be taught how to run away from a boar, or seek high ground. All of these help a child understand the mind of a boar, long before they pick up a sword. Accordingly, if you want her to become a swordsgirl fast, make sure the rest of the culture is steeped to train her to understand how a boar thinks. Once that is in place, you'll be able to train her faster than otherwise possible. [Answer] From all accounts (I have not tried it myself, you understand) no one is going to kill a charging boar with a sword, nor have much chance of surviving. The boar will run right up the sword and take you down before it dies. That's why boar spears have crosspieces: <http://en.wikipedia.org/wiki/Boar_spear> [Answer] I'd like to come at this from a different angle, but it's not going to make you happy. We'll assume that our girl is freakishly big and strong, even as a child. 1) In a medieval village, at age 12 she's a full-time worker. She doesn't have 4 hours a day, let alone full time, to mess around with weapons. Unless, maybe, you can get her some sort of religious dispensation - the local warrior priest has a vision, for instance. 2) In spending this amount of time training with weapons, she's knocking herself out of the marriage market. Medieval husbands simply have no need for swordgirl wives. Running a household is a full-time job, and being pregnant/nursing is going to put a major crimp in her training. So why in the world would her parents approve? She and her siblings (if she has any) are the ones who will take care of them in their old age. There's no Social Security, you know. Not only that, because she's freakishly big and strong her parents are not going to want her to waste time being unproductive. 3) I notice you've changed the target challenge from wolves to boars. And you're not getting much support for that, either. Well, there's a reason for that. Swords are for killing people. They, basically, suck as hunting weapons. So if you want your story to make internal sense, you're going to have to figure out a way for her to go after people. Not only that, if she's going after people she's either going to have to learn sword and shield work or figure out how to avoid those patrollers who keep down the bandits. Certainly they're not dumb enough to fight without shields. She's also going to have to figure out how to get hold of some armor, and armor was expensive back then. [Answer] You are coming at this from the wrong angle. Hog hunting with knives is a thing. So it doesn't require really much training at all beyond some basic competence with a knife, knowledge of hog anatomy, and some practice. Could probably be learned in a month or less. The real problem is physical. A 12 year old village girl is gonna be need to be a burly heavy set girl to have a realistic chance of grappling a boar long enough to get in a fatal stroke. But it can be done by an 8 year old boy [youtube video](https://www.youtube.com/watch?v=PnPEiKu5crM) so it certainly isn't impossible given the correct circumstances. Is this a wild boar that has already been chased and pinned by dogs (otherwise it is unlikely a human could even catch it in the wild) or is this some sort of arena fight with a boar specifically raised to fight humans in some way? The former greatly favors a human with a little skill and lots of gumption, the latter is more like a bull fight, which is largely skill. There are child matadors who can kill full sized bulls in their teens after a few years of training. Combat sword fighting and animal hunting have very little to do with each other beyond a basic level of physical fitness and a similar core natural aptitude set (speed, reflexes, etc). Without an understanding of boar anatomy and their basic movements it is highly unlikely that even a master swordsman can safely kill one. But he could probably learn to do so in just a few weeks or even after watching a few fights. But a total novice would only need a few months of training to take a boar down provided he had the physical capability necessary and the right tools. [Answer] Finally an easy question. There is nothing that makes impossible a village girl to be a swordsgirl. Is she health? Has all the limbs? Can walk without fall face down to the ground? What she need is an instructor! And time! A specially designed sword could help because a girl need a killer but lighter sword. All I have read in old cloak and sword books point to anything around two years. This good movie is an example. It is based upon a novel by Rafael Sabatini: <https://en.wikipedia.org/wiki/Scaramouche_(1952_film)> But what she could need more is training. Without training with different partners from time to time she could loose all the vital sword skills she has. > > improved scientific knowledge from spirits / divination or some such with common elemental magic (Earth, Wind, Fire, Water...) and Alchemy (Chemical Element Transmutation...) > > > Do you know the "improved scientific knowledge" part of the above text have destructed any sense of logic? It is magic or it is science, not the two. ]
[Question] [ Throughout science-fiction, from Star Wars to sundry others, we see characters manipulate holographic images as if they were solid objects; shaping them, tapping them, manipulating them like some kind of 3 dimensional touch-screen, even though all they are are projections of light. How would this work in reality? Is there a way to use a hologram like a touch-screen? [Answer] ## Gesture recording There's a quite workable solution, without beams crossing the room. You project the hologram as usual, in front of the person. Then you'd have video cameras on the other end, recording the person's gestures. A [vision software application](https://en.wikipedia.org/wiki/Computer_vision) is connected to two cameras, correcting for perspective and calibrated using certain objects. It can pass the touched coordinates to the program running the hologram and here you are, a non-solid touch screen. > > The invention belongs to the technical field of human-computer interaction, and is a visual, operable and non-solid touch screen system which comprises a computer, two network cameras, a head-mounteddisplay and a calibration reference object, wherein the calibration reference object calibrates a virtual touch screen. > > > <https://patents.google.com/patent/CN101673161A/en> 3d cursors The above invention actually implements a 2D interface, hanging in 3D space. A quite "normal" touch panel, in fact.. An interesting challenge: a hologram actually has depth. Maybe, a 3D mouse be possible, allowing the person (eg: a surgeon) to reach into the projected holographic scenery. [Answer] Update: There are a few conversations that I've had to repeat, so I figured I'd include the responses here. A *hologram projector* isn't a real thing. We see this so much in movies and television that we forget that it has the same real-world viability as artificial gravity. You need a reflective surface to exist at the spot that you're making glow, which means it has to occur inside of a display space. This makes it a holographic display, not a projector. You cannot reach into a holographic display. This would involve your hand going through and disrupting whatever the hologram is being projected onto. The way around this is to use [augmented reality glasses](https://www.microsoft.com/en-us/hololens). The glasses are required to ensure that different images are shown to each of a person's eyes. For proper AR, they also need to allow light from the outside world in, otherwise they're actually just VR. There are [many implementations](https://www.ultraleap.com/) of [hand-tracking machine vision](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8321080/) projects. It takes less processing power if you wear a clearly marked motion-capture glove, otherwise you need to ensure that the hands are well lit. When you combine these, you have holographic input and output devices. You need to set a command structure that differentiates between selecting, grasping, and pushing gestures, but at that point, it's just a matter of defining the protocol. [Answer] ## Visual theremin The [theremin](https://en.wikipedia.org/wiki/Theremin) is a no-contact musical instrument which is "played" by moving hands within an oscillating electrical field. This electrical "pitch field" is picked up by separate pitch and volume antennae, which are used to modulate a musical tone. As the hands of the performer, which act as capacitors in the circuit, move in relation to the antennae, the field is perturbed. In the case of the theremin, this produces alterations in the pitch or volume of an otherwise constant tone. In your case, the onward processing can be a movement on a 2d or 3d space mapped to the hologram, and certain gestures can be mapped to an "interaction" (swiping, tapping etc). The advantage of this design is that the operator's movements directly act upon the signal, as opposed to requiring an entire separate apparatus (cameras and machine vision processor) to detect and digitise the user's movements. The drawback is that it's somewhat more temperamental and constrained. Think of it as the difference between using a radio app on your phone vs an in-built FM receiver. You could have high-end systems designed to work with expensive multichannel cameras, as per others' replies, with fancy proprietary iGloves that guarantee a smooth, interference-free detection. And you could have rugged, industrial use devices that are little more than an emitter and two antennae, cranky and difficult to work with except for skilled mechanics and suspiciously talented protagonists, but far more durable and portable. [Answer] Detect the heat signature of fingers Humanity is [already developing 3D thermal imagine](https://www.flir.com/discover/rd-science/development-of-a-3d-thermal-image-camera-system-to-perform-analyses-from-the-air/), though inelegant compared to what you're trying to do, the premise is simple. Detect the tips of people's fingers. I can easily imagine a device that detects the moment a finger/thumb (hereafter "fingers") enters the holographic space. Think of it from a 2D perspective. That first moment would look lime one or more infinitely think thermal discs. As the hand pushes further into the holographic space, your computer begins to detect an elongation of those thermal signatures. It's beyond plausible that it would recognize these as fingers, and finally see all those fingers connected to a hand. The real trick is something along the lines of a double-mouse-click. How do you know when the finger has done something that would cause an expected result? I believe buttons would be simple. The moment the tip of the thermal image crosses the known location of the button, the button's [callback function](https://stackoverflow.com/q/824234/4526528) is activated. A little more complex would be spinning a wheel. In this case, the tool could detect multiple finger crossings, allowing the wheel to be turned at the rate of motion of the fingers. If a single finger touches it, nothing happens. Part of the problem here is training the user to stop their fingers near the outer edges of the wheel (overcoming the lack of touch will take training, but it's not impossible, there's an art form with Japanese Katana that fights choreographed imaginary battles — and the goal is to respond realistically to the non-existent combatant). Even more complex would be grasping a holographic object. In this case, it's all about how you program the response to those fingers. In a high-sensitivity mode, tapping the object would cause it to move. In a low sensitivity mode, grasping the object with a brief pause (the delay between those blasted mouse clicks) to let the system know you really intended to move the object. So, yeah, I think this is not only believable, but plausible, and that we're working toward the technology already. [Answer] # Sonic resistance In addition to the hologram, have a sound machine nearby that can make waves of sound. It carefully constructs waves of sound to resist people's hands when they touch them, like a light wind. As such you have tactile feedback from touching the screen, and a mixture of light sensors and sound sensors can say exactly where your hands are. # AI interpretation You'd have an AI which maintains a profile of each person which predicts what they want the screen to do. This helps adjust for people with reduced mobility or unusual motions. Every screen would be calibrated for a standard set of motions, but if you had time you could train a screen to respond to any motion you wanted, from blinking to tapping fingers. [Answer] We actually have tech like a " projected laser Keyboard" and sight based key selection (Done by having a camera that notes where your eye is looking to manipulate the interaction). However, the reason these technologies aren't wide spread is because they are difficult to manipulate with any consistency. In the case of a laser keyboard, one problem is that there is no tactile response... that is, when you press a key, the depress and return is a mental signal that the key has been interacted with and you don't need to press it again. This makes typing faster and more efficient and most people can type without looking at their keyboard (the reason why the F and J keys have a raised bump is so you can find them without looking. Knowing where they are located can help guide your hands to all letters in the alphabet in an efficient manner. Because the projected keyboard is non tactile, these features are lost without any net benefit to the typist. Additionally, the reason both of these keys work is that the interface is watching your movements, which isn't as reliable a method as button pressing, which is a passive system. This isn't to say holograms don't have a place as 3D projection has it's benefits (especially in a Sci-fi space opera, since space is a 3D environment, and a 2D map of space routes might not take into account that a planet 10 light years on an XY projection is 1000 light years below that position if you keep on the same XYZ plane of Earth. [Answer] Eye focus tracking The system tracks the user's eyes and can tell exactly where they are focusing. The hand motions are simply an aid to this. e.g. the eyes focus on the object you wish to manipulate, then your hand gesture does what you want to do with it. (Move, close, embiggen, etc.) [Answer] a technology like that already exist, all be it it... not working well yet.[see laser keyboard](https://electronics.howstuffworks.com/gadgets/travel/virtual-laser-keyboards.htm) basically you can get a "touch" detection with an IR censor that tell you where the screen has been touched, assuming where are talking about screen that are fully non physical. the only issue with that technique will be that you won't have any touch feeling. a cool idea i do have for those screen would be them to not be laser related but have a tiny swarm of robot who just form everything you want and emit the light themself. therefore you can actualy touch them another thing that might work, and who can be fun is: there are no actual projection on the screen, you need an eye implant and to connect to the screen, then everything is projected in AR in the eyes of people who look at those, those tablet would just therefore be an AR enchor point [Answer] # Ultrasonic haptic feedback A phased array of ultrasound emitters can produce tactile sensations (vibrating a point or area on your fingers/hand). There's [ongoing research in this area](https://core.ac.uk/download/pdf/288313376.pdf), and there appears to be at least one [commercial product](https://www.ultraleap.com/haptics/) available. It's not going to feel like you're touching or grasping a solid object, but it can provide useful feedback. [Answer] The keyboard and other input devices are physical. They provide the physical feedback, possibly even some sound for the clicks. But they are not connected to anything, not even through Blue Tooth or similar means. A holographic overlay gives you visual information about what you are doing. And various visual sensors (lasers, infrared sensors, what-have-you) detect what you have clicked. Since the keyboard etc. would not have any electronics in them, they could be relatively cheap and light. All they have is comfortably springy keys. The mouse has a little thumb-wheel that rotates with an agreeable amount of stiffness. And so on. You could mount them on any convenient mounting device. And the screen would be holographic, requiring no additional desk space. Straightforward customization would be possible. You select the size and physical arrangement of keyboard etc. that you prefer. Bigger or smaller keys. Or qwerty versus dvorak. Or even those freaky two-part keyboards. Then you overlay the hologram to match the physical config of the device. You could even have things such as a keyboard over here for when you are sitting, another for when you are standing at some equipment, even one for the bathtub. The hologram over the keyboard and showing the screen (screens?) would jump from keyboard to keyboard. Combine with additional gestures such as waving, swiping, pinching, etc., as various tablet devices have. It becomes as simple or complicated as your needs and desires require. [Answer] It is possible to track a small object in 3D space with around mm precision with current technology. The example below was implemented about 35 years ago!. This is usually done with wiring linked targets - which is no problem for the application that you envisage, but wholly unattached is possible. One method of several is to have 3 very small coils orthogonally positioned (one each in X Y Z axis relative to eg the wearers fingertip, and have the space of interest scanned by 3 orthogonal fields. Mounting two coil sets a small distance apart (see example below) allows position and full orientation to be determined. --- Here is an example - tracking a blow-fly in 3D space. 2 orthogonal coils of about 100 turns (using 10 um diameter wire !!!) of 2mm diameter or less are mounted on a blow fly and tracked in 3D space. They use a halter with wired connection without impeding the blowfly's flight significantly. Position accuracy of 1mm with a 1 kHz update rate was achieved.** ![enter image description here](https://i.stack.imgur.com/2GVGo.jpg) Photos from paper here: [Using miniature sensor coils for simultaneous measurement of orientation and position of small, fast-moving animals](https://pure.rug.nl/ws/portalfiles/portal/3153285/c2.pdf) This is a related follow-up paper. Not content with the stunning initial result they mounted a second coil triplet on the blowfly's head so they could tell where it was looking while in flight. [BLOWFLY FLIGHT AND OPTIC FLOW II. HEAD MOVEMENTS DURING FLIGHT](http://jeb.biologists.org/content/202/11/1491.full.pdf) Usefully related. [AC magnetic field detection system applied to motion tracking](http://www.cedrat-technologies.com/fileadmin/user_upload/cedrat_groupe/Publications/Publications/2010/09/AC_magnetic_detection_SENSOR_2010.pdf) [Answer] This was mentioned in a couple comments but I think it deserves an answer, the Meta Quest is already doing this quite nicely. It identifies the location of your hands without controllers and brings them into VR allowing you to see them and use them to interact with other objects. It's all done with the existing tracking cameras built into the headset, no external devices required. There are two levels of hand usage now, used to be you could only use gestures to select and move items and access a few menu buttons--but a new update has allowed you to actually see your hands and fingers represented in their actual positions, this is only supported in a few apps right now. Netiher mode is really great for playing games because they don't have buttons or joysticks but this should improve over time as better gestures are developed. To take it one step further, some keyboards can communicate with the quest and can be brought into VR. Combining this with the ability to see your hands is supposed to let you type quite well with the headset on. The one issue I've heard of is when you place one hand in front of the other, the headset may lose track of the blocked hand because the only cameras are in the headset. There are also haptic feedback gloves coming to market, when you touch your hand on an object it should feel like the object pushes back against you, or when you try to squeeze something it can prevent your fingers from closing. I even saw a demo of one that used low level electric shocks to directly manipulate your muscles as well giving you the feeling of something pushing back. The exact same technology should work for holograms (They are nothing more than VR projections wihtout a headset--the interactions would be identical). The only issues I can imagine are hardware design, like projecting into a space where your light could be blocked by a hand. [Answer] In current technology a computer generated hologram would be able to monitor it's own output using a stereoscopic camera or by using unseen infrared or UV light bar pattern sweeps of the region looking for fingers approaching or interacting with the display region. Imagine something like a current technology 3D scanner such as an Einscan combined with a holographic projection. One can use pre-exposed and predrawn holographic images currently and simply choose which ones to display in reaction to the input. Making it seem real and less fake would require lots of pre drawn and exposed holographic film. If there is a currently available computer generated hologram display then one can add the scanning feature to it and you have only the limits of software and your imagination. One should also have a complete lack of any worry about contributing nothing of worth to society. Sliding displays like in The Minority Report would be annoying because there would be someone next to you on the bus with their tablet gesticulating wildly, and when they elbow you in the chest you will wish you never wished for interactive holograms. One can simply don 3D goggles for computer generated virtual reality, or transparent virtual heads up display glasses or direct to the eye projectors and be presented with mixed reality/virtual reality, the requirement to be able to manipulate the results only requires that is be able to scan the motions of your hands instead of measuring the motions of the hands by wearing vr gloves. I would Not want to be continually driving over freshly fallen people wearing VR goggles whose lagging internet connection caused them to miss the curb and fall into the street. Commute times are already long enough. I've nearly hit several people when I borrowed my wife's prius IV and those people simply had earbuds in and were peering too intently at their smartphones. There should also be a small and separate fenced-in area in parks for people larping with sticks and swords, pretending to be dogs, wearing fursuits, using VR goggles, or ALL of the above. A place well apart from the rest of humanity who can then use the park like me- jogging and carrying a large dual cassette boombox. ]

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