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[Question] [ I am building a world with a small island nation trying to defend themselves against a large continent with medieval (1200-1300) level technology. They lack metal and use obsidian and stone for weapons and tools, similar in technology level to the Aztec around 1500. **How could they feasibly synthesise an explosive and how would they go about doing so?** [Answer] ## Yes they can. First, we need to know what [Gunpowder](https://en.wikipedia.org/wiki/Gunpowder) is. Luckily we have Wikipedia, they will need an inventor. Will make a good story on how to get to gunpowder, methinks. Your island(s group) are very lucky. A few of them have huge bird colonies. Those big bird colonies create a lot of [guano](https://en.wikipedia.org/wiki/Guano). So you can feed a lot of people from the small area you have. Good, you will need your people to be numerous. But you can create part of [gunpowder](https://en.wikipedia.org/wiki/Potassium_nitrate) from [guano](http://pigeonsformeat.com/index.php/utility-pigeons/10-gunpowder). Next step is sulfur. Again, you have hit the jackpot! A volcano with a [Sulphur Mine](http://www.bbc.com/news/world-asia-pacific-12301421). You might want to create a lower caste to get this stuff. It really smells. You know, like hell or another bad place. The last step is charcoal. Now that is easy, we get that from burned wood. Now wood will be a bit of a resource bottleneck on an island. But for the greater boom, it will need to be done. **Oke, now we have Gunpowder, how do I use it?** In the west, it is best known for its use in cannon and rifles. Those things are not available to you, for lack of metal (working). So I suggest, go with mines and grenades. Both will need [fuses](https://en.wikipedia.org/wiki/Fuse_(explosives)). You have the material to make those, so no biggy. **Mines** are best used for guerrilla activities. Blow up their boats when they are close to the shore. Explosions work better under water. You do need to do some waterproofing. I think you can use animal fats for that (thank you birds). **Grenades** will be a tennis to basketball size affair. An explosion is nice, but it is the shrapnel that will kill. So use a hollowed out coconut for the shell. Make it as thin as possible. Then line it with stones. Sharp ones are preferred. In the middle, you place the gunpowder. Attach fuse, light, and throw at an enemy. Make those foreigners sorry they ever came this way! [Answer] **GUNPOWDER!** > > Wars were fought over islands that were covered feet deep in seabird guano. > <http://pigeonsformeat.com/index.php/utility-pigeons/10-gunpowder> > > > The wars were fought because guano is a rich source of potassium nitrate, which is the oxidizer in gunpowder. You need sulfur for gunpowder. If they are on a volcano they are in luck as regards sulfur - they can just go pick it up. A coral atoll, not so much. How cool is this volcano with burning sulfur I found at [nationalgeographic.com](http://news.nationalgeographic.com/content/dam/news/photos/000/758/75878.jpg)? [![enter image description here](https://i.stack.imgur.com/iS0aP.jpg)](https://i.stack.imgur.com/iS0aP.jpg) The third ingredient is charcoal. A beach, a hole, a fire and a bunch of coconut shells will make you fine charcoal. Those are the ingredients for gunpowder. I would not encourage the obsidian cannon. [Answer] [Gunpowder](http://cavemanchemistry.com/oldcave/projects/gunpowder/) is within their realm of options. It requires three ingredients. * Sulfur, this will be the hardest of the three. It must be mined. Mining without metal is hard but not impossible. Can be found near volcanoes. Those seem fitting for an Island nation. * Saltpeter could easily be extracted from guano with a process quite similar to potash. Hardly a modern and sophisticated technique. * Charcoal, come on it's likely they know about charcoal. But if you want to mix it up. Pure enough alcohol or Sugar could suffice. So there is your basic gunpowder. Not to make it useful without metal is a bit harder. There is evidence of bamboo cannons but it's likely those are at best unreliable. But wooden or bamboo barrels might work with stone projectiles. If you can make cannons, you can make bombs. Fill a bladder or wooden barrel with gunpowder mixed with shrapnel. I guess granite might do the job. Obsidian seems to brittle to be of use and regular stone not sharp enough. But granite chips would cause a nasty wound. [Answer] You could use guncotton. First, have your alchemists heat Melanterite, and then add water to the resulting sulphur trioxide to get sulphuric acid. Then get new alchemists (it's a strong exothermic reaction) and have them add some saltpeter to your sulphuric acid to produce nitric acid. The resulting mixture of nitric and sulphuric acid is mixed 15:1 with cotton (which means you need tropical or subtropical climate on your island). After a few minutes your guncotton is washed with cold water and then dried and ready to use. Expect to lose a few alchemists before they figure out the importance of washing the guncotton. [Answer] Better use what you already have: any flammable material, ground finely enough, is explosive. No need to resort to complex chemistry likle gunpowder. It's all a matter of surface area. A lump of coal burns slowly; grind it up and it burns much faster. Suspend coal dust in the air and you have a highly explosive mixture that has destroyed many mines. See <https://www.cdc.gov/niosh/mining/features/coalmineexplosion.html> Similarly, flour mills and silos are frequently destroyed by exactly this type of fuel-air explosion when powdered material ignites in the air. <https://www.independent.co.uk/news/uk/home-news/cheshire-flour-mill-explosion-four-missing-workers-named-10400399.html> The challenge is to weaponise this effect. Modern thermobaric or enhanced-blast weapons do it with powdered aluminum packed around conventional explosive. Your stone-age natives will use flour or similar, and will need a clever means to scatter it in the air and ignite it -- but the explosive itself does not require anything so tricky as gunpowder and can be made easily enough with stone-age technology. [Answer] There are a large number of explosives out there, but let's go with the one that comes top to everyone's mind...**Gunpowder** You need 3 things to make traditional gunpowder. Sulphur, which might be readily available on a volcanic island. Saltpeter, which can be harvested from urine. Finally, you need Charcoal, which you can get if you have fire and trees. Mix in the right proportions and you have a basic black powder. A large enough volcanic island and large enough population and you have all the bases covered. As for Metal, it's not necessary at all. Firecrackers are pretty much gunpowder in a tight paper sleeve. Everything else is just a matter of scale. Metal turns out to be useful when you are trying to generate shrapnel or to make firearms, but there are other ways you can get some devastating devices without having to resort to metals. The Korean Hwacha is a pretty terrifying device. It's basically a rack of around 200 heavy, rocket propelled arrows. You can look up some cool videos on it, and the Mythbusters one is very cool. If you have obsidian to use as arrowheads, the effect could be very scary. Next we have Grenades. They used to be a clay pot with a narrow neck, a plug and a fuse. Imagine the iconic picture of a ball shaped bomb with the fizzing fuse. Those were bad enough. Now imagine an old time grenade with obsidian shards embedded into the clay. Nasty! At any rate, metals aren't necessary, but they tend to give more options. [Answer] As others have said, gunpowder. However, I disagree about cannons not being possible. They won't be good and they will be fixed mount but if the access to your island is limited that need not be a showstopper. Take a wooden gun barrel (yes, it can't last) and bury it in a **lot** of stones/sand of mixed sizes. It won't be perfect but most of the force will still propel whatever you are shooting. It's the mass piled on top that resists the force, not the gun barrel itself. If you can make concrete (doesn't need metal, doesn't need any more chemistry than gunpowder--it was discovered earlier) you won't have a problem with your gun burning up. I don't think you'll be able to do heated shot even then, though. (Heated shot is normally done by preparing the gun minus cannonball, getting the cannonball as hot as you possibly can, you load it and immediately fire, before it's heat gets through your wadding and lights the gunpowder. [Answer] [Lycopodium powder](https://en.wikipedia.org/wiki/Lycopodium_powder) This may need an ignition start. It is made up of clubmoss spores. It has been used in fireworks for centuries. Found naturally, just collect it. ]
[Question] [ **What requirements would a meteor have to satisfy, to approach Earth unrecognized until hitting the atmosphere and cause climatic changes after the impact?** * The meteor should have at least a circumference of 500 meters at impact to cause something. * It might have to hit earth at land because at sea there would be tsunamis and mostly no climatic change. * The climatic changes should be an impact winter but if there are other ideas they are very welcome! * If camouflaging the meteor is naturally possible then i would prefer this way. If not we are at the actual technology level. Edits: * The Meteor should remain undiscovered until the discoverer has no time left to make his discovery public before the impact. [Answer] ## **Cover it with carbon black then approach from the sun-ward side** This is something of the current nightmare scenario for real life planetary scientists. An object covered in carbon black between the star and an observer is incredibly hard to see against the black background of space since the IR radiation from the star is radiated back towards the star instead of towards the observer. Carbon black has an [incredibly broad absorption spectrum](http://www.pcimag.com/articles/86552-when-black-is-white) that covers the entire visible spectrum and into the IR range. Because of this broad absorption, there is very little visible light for a conventional telescope to detect. In addition, trying to pick out a very dark object in the glare of a star is very difficult. [Answer] **Paint it black.** Have it moving really fast, and have it come in from above or bellow the plane of the solar system. If it was painted black(with a nice thick layer of some some kind of tarlike substance) they probably wouldn't see it coming at all. We just don't watch space that carefully with very many telescopes. If we didn't know where to look we'd have no chance and if we did know where to look we might still miss it. It's really hard to spot even much larger objects on slow lazy swings around the sun. Additional details for this kind of scenario: [How far away could Earth detect a projectile travelling at relativistic speeds?](https://worldbuilding.stackexchange.com/questions/16724/how-far-away-could-earth-detect-a-projectile-travelling-at-relativistic-speeds/16726#16726) [Answer] # The Science Fiction Method Get the whole thing painted with [this type of paint](https://en.wikipedia.org/wiki/Radiation-absorbent_material). .#start rant It would be *practically* impossible, but who gives two dimes to practicality when you are into making comets invisible from detection? .#end rant Also it should be a small to medium sized comet. You cannot expect a huge [Baptistina](https://en.wikipedia.org/wiki/298_Baptistina) sized body to not be identified due to its gravitational effects on nearby objects when travelling in the inter-planetary space. # The Other (Practical) Method You would need to hack into the computer systems of NASA and European Space Agency and shush out any and all information they transmit about the comet. The comet might still be visible from naked eye by the folks up there in ISS, but it would only be a few minutes between seeing it and it crashing down into Earth's atmosphere. [Answer] ### Hide it in full view — Just make it Fast EnoughTM Make it small and *fast*. The important thing is the impact energy; a very fast and small enough thing, painted yellow and red with the sign "LOOK AT ME, I'M COMING" is practically as good as invisible. Mandatory reference to [Randall Munroe's What If](https://what-if.xkcd.com/20/) site. (By the way --- in that case I really suspect that hitting sea or land will make little difference. Couple of kilometers of water instead of air will be just a microsecond nuisance). [Answer] ## Have it approach from *lots* of different directions. If your plan is to *intentionally* harm your target planet (and you have unlimited resources and very good orbital mechanics at your disposal) then you could have your meteor approach in 100,000 magnetically charged pieces, converging on a single point somewhere just inside the Earth's orbit. Individually they'd just be too small to see from any reasonable distance but collectively, once they hit each other they would stick together to form a gigantic meteor that seemed to instantly appear from nowhere before [dropping onto Paris](https://www.youtube.com/watch?v=xhtdD4hHboU&feature=youtu.be&t=8s). As an added bonus, you could paint it whatever colour you please. It really wouldn't make that much different since the pieces are tiny. [Answer] I was thinking about suggesting maybe a fragment of neutron star since that would allow you to get the same mass in a much smaller area. Unfortunately it seems the smallest size a neutron star could be and remain a neutron star is 0.1 stellar masses. That's 33 thousand times the mass of the earth so doesn't really work. (see <https://physics.stackexchange.com/questions/143166/what-is-the-theoretical-lower-mass-limit-for-a-gravitationally-stable-neutron-st>) Average meteorites though have a density of 3g/cm. Make the meteorite out of something like gold or uranium and you can get the density up to 20g/cm. You should also make the meteorite spherical to get as much mass as possible for the cross section. Unfortunately square-cubed is not working for us here as a factor of 3 increase in density does not give us a factor of 3 decrease in cross section. However it doesn't need to be a sphere. If you can control the meteorite's orientation and rotation finely enough you could shape it like a very long rod with one end pointed towards the earth. Make that end black and inclined at an angle so it doesn't reflect anything back towards earth. You can now make the meteorite as massive as you like by extending the length of the rod without making it any more visible at all. An important point to make though is that there is no need to camouflage it at all. We do not watch all the sky all the time, and not even all the meteors that we know are out there have been found yet. You don't need to explain a meteor not being spotted unless you want that explanation to be significant. It's actually more likely we would not spot one than that we would. [Answer] 500 meters isn't very big. They are hard to spot at the best of times. The bulk of meteors are in the plane of the ecliptic. A long period asteroid at a high angle to the ecliptic may not have been spotted yet. If it comes to Earth after closest approach to the sun, then it would have been in the glare of the sun for it's final approach, and far enough away to be hard to find before. It takes several locations to pin down the orbital parameters of an asteroid. MANY asteroids have been found, lost, found again. Remember too that Jupiter keeps re-arranging orbits. It's quite possible that an asteroid whose aphelion is out close to jupiter could lose enough energy that the other end of it's orbit becomes a colider. Some of this will depend on the funding that the skywatchers get. There is a lot of sky out there. It doesn't all get photographed every Tuesday. ]
[Question] [ Inspired by comment under [this question](https://worldbuilding.stackexchange.com/questions/5078/what-would-the-world-be-like-if-computer-software-did-not-have-any-undo-featur) > > "Darling, does this dress make me look fat? > > > QUICKSAVE > > > "Uhm ... no?" > > > WRONG ANSWER, WANNA TRY AGAIN? > > > We all dreamed about having possibility to redo something in real life. There are [movies around it](http://en.wikipedia.org/wiki/Groundhog_Day_%28film%29) but they seem to be all based in pure fiction. So, **Is there some possibility to have undo for real? And how to make it reality?** Rules: * Stay inside current science knowledge * If you need to go to the future, such future should be plausible given current science knowledge * Any form of magic, or all-powerful being appearing from nowhere (a.k.a The God) is not allowed * Does not matter how pricey it is. You have [all money on Earth](http://theinfosphere.org/Bad-ass_gravity_pump) * The same applies to energy consumption. [Answer] Can do with current technology, but it will require all the money in the world... Send me all the money in the world and I will let you in on the trick! No seriously, a current day totalitarian state could mandate that all citizens attend conditioning classes as part of their juvenile education system. In those conditioning classes, hypnosis and subliminal messaging could be used to "program" each citizen's mind with a command phrase. High level officials within the state would know the command phrases such they would finally have the absolute control that Leaders have always dreamed of. For example: > > "Does this dress make me look fat?" > > > "No Dear, the donuts you constantly stuff in your maw are what make > you look fat!" > > > ...wife glares furiously, then raises butcher knife. > > > "rosebud" > > > ...wife's eyes glaze over, lowers knife. > > > "put away the knife. forget everything you or I have said since you > put on that dress. then wake up." > > > ...wife complies, then turning to her husband asks, > > > "Does this dress make me look fat?" > > > [Answer] Fork a software copy of your wife (she pre-approved such copies) and a copy of yourself and run them both in a simulation space that runs much faster than real time. Have the simulated you answer your simulated wife over and over, repeating the copying and answering procedure until the simulated you produces an answer that pleases both simulated you and your simulated wife. Have the umpteenth copy of you report back the optimum response, whereupon you halt execution of all the copies and answer your wife in real life. [Answer] No - not without limits of physics. Time flows in direction of increasing entropy. Undo will decrease the global entropy, negating thermodynamics. Time means causality. Reverting time reverts causality. Do you really want to dive that deep? [Answer] There is an example in Science Fiction where this is done - which is The Void from Peter F Hamilton's Commonwealth Saga. It's an artificially constructed portion of the universe where the rules have been re-written on a quantum level. One of the consequences of this is the ability to rewind time. The Void actually remembers all previous states and is able to rewind the universe internally to the remembered state while not rewinding the traveller(s). This seems to me like the only way in which something like that would be possible, you need something to remember the prior states and a way to reset everything back to that prior state. Of course if everything goes computerized and virtual then this becomes easier, we already know how to rewind computer time. Of course that doesn't work when you are talking to a real human being who would still remember no matter how often you pressed the undo button... unless real-time memory editing was a thing. [Answer] This isn't possible without a huge uptick in technology. You certainly can't go back in time, because that would violate, among other things, causality. Also, going back in time wouldn't help, because you'd still have the past you screwing up the answers to those questions. The alternative, by the way, is to kill your past self - but then that would kill your *current* self, and so we enter yet another paradox. So let's get creative. There has been talk of turning people's biological bodies into mechanical ones, and turning brains into computer hard drives. I think this is possible within, say, 50 years - for perhaps a handful of brain cells. On a scale as large as the human brain, it's going to take us a lot longer. *However*, if you devoted all the resources in the world to this task, you could speed up the process a lot. So let's say that all the relevant people in this scenario have computers storing their memories, emotions, and personalities. But they still, for some reason, have normal bodies. Creepy. If you mess something up (although at this point, the question would be more like, "Honey, does this new chip make me look slower?"), there's an easy solution: Modify the hard drives storing the person's memories. Make them unconscious, then use some programming to turn that memory into whatever you want it to be. It won't change your actions for the rest of the world, but you can "change" your actions for all who observed it. [Answer] In theory, one possible outcome of "the singularity" will allow people to transfer their consciousness into a machine. A machine, then, that could significantly alter their perception of the "world", simulating the world individually for each human. Undo would simply rewind the simulation, and change the user's memory of the events as needed so humans could fully interact, and any one could rewind short things. Would probably need to have limits built in, otherwise the world would be in a constant state of rewind. For instance, tiny, localized rewind effects have low to no cost - oops, dropped my phone and it broke, let's go back a few seconds. No need to rewind the day for anyone else, and the user would just have to accept the "lost" time since the rest of the world kept going on. Large area rewinds (The rainstorm caused too much damage), or rewinds that affect a lot of people (sports exhibition), or rewinds that pass through a lot of time (I wish I hadn't entered into this relationship) would require greater resources, such as "lifespan", or would have to require several people wanting the same exact rewind, etc. Then there are human factors. "I wish I hadn't gotten married and had 2 kids" - what happens to the kids if this rewind is successful? "I wish I had killed modern-day-hitler when I had the chance" These problems would be present in any undo system - not just a simulated human system. But as far as a reasonably possible future, many of our time believe the "singularity" is inevitable. [Answer] Yes, it is possible (ish) with today's technology . . . I am not entirely sure how a real life "undo" may be possible, but a prevention of "do" may be by exploiting quantum entanglement between two photons with temporal separation. You would need to capture a photon in a device and have a system periodically read the quantum data on said photon. Now, whenever an unsatisfactory event occurs, you would write the quantum data to that photon. The quantum data will inadvertently be present on the entangled photon in the past, the one captured in the device. Once the device reads the quantum data and collapses the quantum state, you will "receive a message from yourself in the future" warning you of the event that you do not wish for yourself to perform. There is no telling if this device will honestly work, for, if you think about it, many paradoxes are at play here, but this is possible with today's technology. It would not require all of the money in the world, yet it would be very expensive. I also believe that if you had all of the right "know-how", you could build this device yourself. [Answer] This also kinda falls under movies so may not be what you're looking for, but the book behind Edge of Tomorrow came up with a hypothetical science way of resetting time. I asked about it after seeing the movie (as it left all the theory out) and got a very interesting reply, so I'll copy and paste that. From my non university level physics, it actually sounds like something that could potentially work many many years into the future. > > The way they did it is through theoretical particles called Tachyons. Tachyons are like normal particles, but instead of moving through space like a photon or any other particle we are familiar with, they move through time. > > > Every 30 hours the Mimics are able to place a "bookmark" or "save point" of sorts, which gives them another 30 hour grace period. Throughout those 30 hours the "original" Mimic server (the bookmark) will be receiving tachyon signals from its "parallel" server. If things do not go according to plan, the parallel server sends a "reset" signal and it all starts over from where the "bookmark" was. That "bookmark" server will be endowed with all of the knowledge of the 30 hours that are to come, and so can change their tactics. > > > They can do this as many times as they want, and that is why they have been so utterly unpredictable and deadly. > > > Think about it like playing a video game with statically placed obstacles and enemies. You can play a level, die, then jump back, this time having learned something new and now anticipating what you know will come. It isn't a "new" timeline, it is the same timeline. At most it is a very closely parallel timeline. They are just "rewinding" to their save point. > > > [Answer] This is not going to work, assume I know the secret for undo. If you give me 100 $ I tell you how that works. * You give me money * I tell you the secret * You do undo to receive back 100$ * Ops you also undo the knowledge of the secret actually undo could be perfectly possible, but we cannot know that. ]
[Question] [ **TL;DR:** Can human build a computer that lasts for a few hundred years under active maintenance with a limited spare part supply, not too bulky or power hungry, and has the performance similar to a high-end desktop PC in the near future? > > I'm aware of similar questions in this site, like [Preserving electronics for hundreds of years](https://worldbuilding.stackexchange.com/questions/141854/how-to-preserve-electronics-computers-tablets-and-phones-for-hundreds-of-year) and [Computers lasting for centuries](https://worldbuilding.stackexchange.com/questions/28505/computer-that-lasts-for-centuries/). However, I couldn't come up with a reasonable enough design based on the info they provided. The former has the requirement of using regular electronics (which we don't need here). The latter has provided some good ideas, but they are mostly for *large* bases *on Earth*. > > > > > [Space faring robot functioning for 1G years](https://worldbuilding.stackexchange.com/questions/140771/can-a-space-faring-robot-still-function-over-a-billion-years) is also a nice source of ideas, but I don't think it puts the computing power of the machine as a priority, while we do. > > > --- #### Full version with background Let's say people are sending a space probe to some solar system nearby (think of [Project Longshot](https://en.wikipedia.org/wiki/Project_Longshot) but a longer trip). The trip will take roughly 300 years. Since the communication delay will be multiple decades, the probe will have to handle any situation during the trip or inside the solar system on its own. So, we have to install a powerful computer on the probe to make it smart enough, and keep it running throughout the trip (or at least preserving it in a state that can be woken up any time). Here I'm making numbers up. Let's assume the computer's total performance is comparable to a high-end desktop PC today (e.g. i7-12700K + RTX 3080, in any measurement you like (TFLOPS?); details can be adjusted), and its tasks can be distributed/parallelized however you want. It can be custom-built using technology available in the near future (say in the 2070s), and cost isn't a problem. We also assume that any reasonable preservation environment is possible (proper heat management, vacuum, noble gas, constant temperature, anti-radiation, etc.). We can also have some spare part supplied in the probe with reasonable ways to use them. Robots that do simple maintenance can be available if needed (methods to preserve them are not discussed here). There are limitation on mass and power because it's on an interstellar space probe. The computer and its shielding should weigh no more than a few tons so that the probe can fly fast enough. Relying on the probe's reactor, its power consumption should be less than 100kW. The lower the mass and power consumption, the better. Are there reasonable explanations/designs for the setting above? What will the computer look like, or what should be considered when coming up with a design of it? Rough ideas are perfectly okay! I'm not really designing an interstellar computer, but looking for a technical starting point to design other parts of the story. Some limitations I'm aware of: * Diffusion and other degradation within semiconductor chips that makes transistors unusable. Running it continuously for a few hundred years makes matters worse. Is this a big problem? --- It's my first time to ask a question here, so please tell me if I did anything wrong. --- Edit: Explained what I expect to get nicer. [Answer] > > Let's assume the computer needs to be roughly the same performance as a high-end desktop PC (e.g. i7-12700K + RTX 3080; can be adjusted). It can be custom-built using technology available in the near future (say in the 2070s), > > > This is a surprisingly tricky thing that depends on a lot of factors. A major problem with stuff in space is radiation, because there's no atmosphere to attenuate it and science-fictional environments often involve an awful lot of highly penetrating particle radiation emitted by nuclear reactors (or weapons) or from space dust hitting relativistic spacecraft, etc. The 12700K uses a 10nm process, which means that it has very small features of which you can fit a lot on a chip, and which can work at convenient power and heat levels given the speeds and capabilities of the chips. Problem is, those little features are vulnerable in a high-radiation environment... one neutron or an [HZE](https://en.wikipedia.org/wiki/HZE_ions) ploughing through the chip will likely damage many of them, and when you've damaged enough the chip will simply stop working. Compare with a real-world radiation hardened CPU, the [RAD750](https://en.wikipedia.org/wiki/RAD750). It uses a CPU design that's 20 years older, and a process that produces features 15 times larger or more. It has a tenth of the clockspeed, and is only a single core as well. Those bigger, simpler components and careful choice of material mean that the RAD750 will be substantially more robust to background radiation... this will significantly improve its longevity I posit that what your space probe will have will be stuff that is simple and very overbuilt, and because of the continuous risk of random, permanent damage caused by [galactic cosmic rays](https://en.wikipedia.org/wiki/Cosmic_rays) which are effectively unshieldable without an enormous amount of mass, highly redundant. In part, this will involve large numbers of simper devices, rather than a small number of more capable ones. They'd also be more likely to be things like [FPGAs](https://en.wikipedia.org/wiki/Field-programmable_gate_array) (field programmable gate arrays) which you can think of as a sort of reconfigurable microchip that isn't as capable as a purpose-built system but can be much faster than software and can be reconfigured to do the jobs of many different kinds of microchip. That way, you can have a large number of common devices which can be freely mixed and matched, and a standard replacement that can be used for almost any purpose. Even if an individual radiation-hardened FPGA receives serious amounts of radiation damage, it can be reconfigured to route around the damaged areas and continue to be useful in a way than a normal CPU could not. So: * computer that lasts for a few hundred years Potentially, yes. * under active maintenance with a limited spare part supply, Yes. With clever system architecture, this can be made easier with hardware that can "self-heal" or at least be repurposed before needing to be replaced, and a common replacement module can be used for a wide variety of different tasks making maintenance easier and allowing the system to gracefully degrade rather than being rendered suddenly broken forever. * not too bulky or power hungry, "*Not too bulky*" is hard to quantify. On the other hand, being low power is almost a requirement for something that needs to last a long time in space, because high power means high heat and that wears things out. * and has the performance similar to a high-end desktop PC in the near future? I don't think it could be comparable. The total amount of "compute power" is likely to be higher, but it isn't necessarily going to be in a form where you could run the same kind of application on both. Advances in software and technology are going to be pretty unpredictable, but I think you could expect the future computer to give you a lot more bang per buck than today's equivalent even if it were otherwise similar in raw clock cycles or IO bandwidth or whatever. [Answer] In real life humanity launched Voyager I in September 1977. It's still performing reasonably well to this day (November 3, 2022 - 55 years and still going). It is very feasible and realistic to assume that a civilization capable of interstellar travel could one up scientists from the 1970's by at least one order of magnitude. A few things to consider: 1. Have backups. The Voyager probes each have more than one onboard computer, so if one fails there is another one to cover for it. This is not just space vessel design - nuclear power plants and airplanes have multiple computers handling their main function too, in case one fails. 2. Solid state is the way to go. The fewer moving parts your computer has (fans and discs because they spin, for example), the less likely mechanical wear is to become an issue. You probably do have a mostly full solid state computer (except for the speakers and vibration) within grasp right now in the form of a smartphone, so that should be a no brainer for the spaceship engineers. As for computing power, assume Moore's Law is still maintained - or that a breakthrough makes it even better. That's what most sci-fi writers implicitly do. In Old Man's War people have fully aware AI's running on a small chip in their brains, and it's kinda in the early 2100's. [Answer] You will have a problem with circuit aging. This is a well-known problem in chip manufacturing, and there is no known solution. Basically the running computer has electricity running through transistors, and due to a phenomenon called [ElectroMigration](https://en.wikipedia.org/wiki/Electromigration), the structure of the different materials in the transistor gets slowly corrupted, atoms of one will be carried from one side to other by the flow of electrons. This eventually slows down the switching speed of the transistor. It gets worse with higher voltages, higher frequencies, and higher temperatures. A good cooling system should severely limit the temperature but that will not address the voltage and frequency wear. (Edit: I was incorrect about space, apparently satellites use material that is highly conductive thermally to move heat away from hot ICs, this transfers to a larger panel to radiate away the heat at infrared frequencies.) Basically, the chip will fail, if a circuit cannot complete its task within the cycle allotted, it can cause a crash. This can be addressed with backup circuits; basically unused duplicate (or triplicate) circuits on the chip that can automatically kick in and replacea failing circuit. Or whole backup chips; when one gets iffy, we disconnect it and switch to a new one. You can also cut power to the CPU except for brief intervals of operation. In most mission modes, there is no reason to be running the CPU for more than a few seconds per minute, or even per hour, in interstellar space. Just be aware that transistors do age and fail, many modern fast consumer CPUs just are no longer designed to run continuously for decades. Power management is not just to save energy, even if you have unlimited energy, severely reducing power and frequency (and thus performance) when we don't need it is also extending the lifetime of the device. [Answer] ## Cluster many similar computers, avoid single point of failure <https://en.wikipedia.org/wiki/Single_point_of_failure> <https://en.wikipedia.org/wiki/Computer_cluster> <https://en.wikipedia.org/wiki/High-availability_cluster> With some effort in software design, it is possible to implement complicated systems on a space ship like life support or navigation as a *distributed tasks*, that is a designated computer nodes receive commands, which are dispatched to other computer nodes, that may be available, or not (anymore). If it is not, the task is dispatched to a node that is still available. **Redundant functionality** For max reliability, your computer cluster consists of X individual computers, all capable of doing the task. So.. your system will live as long as the longest lasting computer. **Keep lots of computers in store, to be merged into the cluster later on** You could keep some computers in reserve, to be switched on and merged into the cluster later, which will be decided by existing cluster nodes.. Tom's remark below made me avoid using a timer for this, that would introduce a point of failure. The "fresh computers" subscribe to the cluster.. take over critical tasks, like the dispatch.. **Mind sustainability and durability, use a fridge** Even when a computer is switched off, it could still deteriorate. Remarks by user71659: in order to preserve plastic wire isolation and support components, consider using ceramics or glass instead of plastics. For certain materials such as plastics, it helps to store reserve components in cryogenic conditions. **Research properly before deciding the size of the cluster** Test it thoroughly. Set up a cluster of say, 1500 nodes. Let it run for long heavy tasks, and every day, destroy a few of your computers and assure it works in any foreseen circumstance. Use material analysis and statistics to predict fail / shut off for individual nodes. Then, determine the statistic for failure > 500 years.. with the data gathered, dimension your computer cluster. In fact, this research will be the main part of your project. [Answer] ## Look not to the future, but to the past. Current computer tech optimizes for smaller, faster, lower-power computers. The primary mechanism to achieve this is making the silicon features smaller, which is *terrible* for long-term space reliability. Ideally, you want your probe made out of huge chunks of silicon, so that any stray particles can only do limited damage to your device. For reference, consider the curiosity rover (launched 2011) - it needs to do far more complex tasks than an orbital probe, but it gets by with 256MB of ram and a 200MHz clock speed. NASA's budget was clearly large enough to afford a more capable chip (even when the design process started), but the rover fundamentally did not need one. As a general rule, you make things reliable by making them slow, large and simple. High clock speeds and small features are great for running desktop applications, but they're a liability in space. This fact will not change with time - it is a fundamental fact that smaller features are more radiation sensitive. The only possible room for advancement is greater redundancy, e.g. ECC memory, but even the best error code correction will be fried by a well-placed neutron to the memory controller. What you really want are essentially five or six identical *Voyager* probes crammed into one case, which spend most of their lives in sleep mode. For operations, three cores should be activated under some kind of voting system, with failing nodes swapped out for trustworthy computers. It's likely hopeless to attempt to shield your computer from radiation - there's probably a trade-off point at which it becomes worthwhile, but if the shielding weighs more than just adding three redundant systems, you may as well just add redundancy. Mind you, redundancy does not solve everything - there was a famous [incident](https://admiralcloudberg.medium.com/the-dark-side-of-logic-the-near-crash-of-smartlynx-estonia-flight-9001-68b9f42b1fb2) in which the failure of a single switch caused **all four** redundant flight computers of an airbus A320 to fail. One way to mitigate this might be to have two dissimilar, independent computer systems on board, developed by two separate teams - with any luck, any holes in the logic of one team will be caught by the other. [Answer] Two centuries ago, nobody would have been able to conceptualize how a device like a smartphone would work using software. Similarly, there can be technologies that come up later which we cannot think of now. * As an Engineer, if I had to design such a space ship, I'd look for very sensitive materials that can absorb various kinds of radiation. So rather than shield the ship from radiation, I'd create layers that'd actively absorb radiation, to power the ship. It would also need a mechanism to let go of waste/excess radiation. * The computing circuitry need not be static in the way we currently design electronics. It should be designed to evolve and adapt, while retaining the ability to remember/honor its original purpose that was programmed into it. * Communication with Earth does not have to take multiple decades. If a wormhole or similar technology can be created, communication could happen instantly. This could also mean that a maintenance crew could easily reach the ship. [Answer] It is possible to imagine a FPGA that detects the damage and heals it by rerouting the damaged functionality over free reserve cells. It would stay operational as long as there are still free reserve cells to repair the damage. Parts that are not yet damaged would stay in use and the same reserve cells can be used to replace various failed parts. Hence on a long run the system of the same complexity may be able to take more punishment than just a highly redundant system where all unit fails if something gets broken in it. The system may still have two or more redundant brains so that surviving brain could solve the problem how to reroute an fix another programmatically. [Answer] The first digital computers were vacuum tube units. A 'bit' was the vacuum tube equivalent of a flip flop. Normally this is done with 2 transistors. But they *knew* that vacuum tubes break. So the circuit was designed with 7 tubes, and set up in a way that ANY two could fail and the circuit would still work. And each tube had an indicator light (in duplicate) So a bit was a box the size of a small shoebox. A bunch fit in a file drawer style cabinet. Indicator ligths on the front showed if one had a problem. Despite this, there was a whole group of guys with shopping carts full of tubes running around and replacing tubes on the fly. So you build in redundancy. Everything is in multiplicate, with multiple interconnections. ]
[Question] [ Imagine a 1 square km section (including a suitable depth of soil - maybe 100m?) of a contemporary rainforest is transplanted onto the Earth in a time a few million years before the Cambrian explosion (540 mya), to an area which approximates the same surface temperature and precipitation as the area experiences on earth today. **Could we expect the contemporary plants and animals to survive / thrive during that time, and would they out-compete the native creatures?** **Assuming they survive, can anyone speculate on how long it would take for 'contemporary' life to come to dominate the whole planet (or at least the land parts of it)?** [Answer] ***DESTINATION UNKNOWN***: The [precambrian](https://en.wikipedia.org/wiki/Precambrian) represents 90% of Earth's history, and so is a huge and amazingly variable time. Even in the later times, this period is often assumed to be extremely volcanic with lots of major impact events, but the record is very poor as to what really happened. Tuesday could be mass extinction day, but there was no one to record it, and no life of note to care. There are a lot of things we don't know with certainty about the precambrian period that affect your question. Traditionally, the atmosphere in this time was assumed to be very low in oxygen, but there's [debate on this subject](https://en.wikipedia.org/wiki/Great_Oxidation_Event). Much of your life could die within minutes of arrival, including essential insects. There may have been lethal doses of trace gasses that would kill your plants instantly. Conventional plants are used to our air mix, and a sudden change would probably kill them, even if they were somehow self-conserving enough to hold most of their oxygen for internal use (a big if). I'm not certain at what point the atmosphere was able to screen out enough radiation to allow plants to grow outside water, but there wouldn't be an ozone layer like we think of to protect them. A rainforest requires a lot of steady water. We know almost nothing about the weather or water cycle of the period, but it's unlikely to have been stable or consistent. Land would not retain rainfall well. Your forest would need to land in the luckiest place on Earth (literally) to even get the water it needed. The most likely survivors of your drop would be bacteria, and they would potentially be quite advanced compared to their local ancestors. This doesn't guarantee they would live - local conditions could be bad, and local bacteria would be well adapted to the conditions then and there. It is not impossible that the addition of modern bacteria could have a chilling effect on eukaryotic evolution. Better adapted bacteria might outcompete early eukaryotes for essential survival niches. Any introduction of modern life to the precambrian environment would need to more resemble terraforming than a random drop of land into an ancient world. Specially adapted lichens would likely hold up well, as would some single-cell animals, possibly some sponges selected for local foods and conditions and various sea plants and planktons selected and/or modified for local conditions. Your time travellers would need favorable starting conditions and broad distribution to avoid catastrophes. After a few million years, your inserted select organisms ***may*** have transformed things enough to allow more advanced plants, animals and fungi to be introduced. [Answer] The soil would be lacking a lot if not all of the organic part which makes the difference between a proper growing ground and simply crushed rocks. This would mean that any exchange with the surrounding environment would likely impoverish the transplanted biome, affecting its wellness. Since a (rain)forest is the final stage of a sequence of steps starting with pioneering plants, I am confident most of the plants would suffer from the non favorable environment and wither. This would affect all the food chain, which is based on those plants. I am not sure that the modern biome would outcompete the native lifeforms, for the simple reason they are better used to those particular conditions. [Answer] If the rainforest is transported with **all the supporting ecosystem** (bacteria, worms, bees etc.) and if it is transported to a **favorable climate**, then **yes, it will thrive**. Some of the species would go extinct, but the rest would be very comfortable. There is just nothing that can threaten this patch of rainforest in late Precambrian. What would be the problem for the modern life is to expand out of this little foothold in the ancient world. As other people have mentioned, Precambrian landscape was very barren. Most of the plant and animal species of the rainforest just can't live there. But a few of them can. So autotrophic species like mosses and lichen will start slow expansion. If will take many thousands of years for them to expand over the surface of the Earth, but eventually they will get there - simply because there's nothing to stop them. Their competitors, ancient lifeforms are hundreds of million of years behind in terms of surface adaptation. After primary producers would colonize barren world, other organisms, like bacteria and fungi will follow. Eventually, a soil will form and modern life will colonize entire surface of the Earth. I'm sure that will happen in less than one million years. It is a very good question what would be happening in the seas. At first, rainforest life would have no adaptation to live in sea water. But evolutionary pressure would undoubtedly make seawater organisms from freshwater and terrestrial ones. Whales and dolphins had already walked this way, and in Precambrian, some species will evolve to eventually dominate the seas. That should take more than one million years, and native species may offer some stiff competition. [Answer] For most on-land contemporary plants and animals Earth would by lifeless - all life was at narrow strip in seas and lakes along the coast. All landmasses were just barren rocks were even deserts plants wouldn't live. So all of this 1 sq miles rainforest would just die out qickly without even having contact with precambrian life. BUT there is some water and surface based plankton life in rain forest. I.e. some unicellular algae and very small crustacean. These are extrimly advanced for this time. And if they somehow managed to get into water (like by the wind) with then plankton - they could form new modern-like plankton layer and than evolve into something. So all we can get at best-case scanario is premature Cambrian explosion with slightly different ways of evolution. This can dramatically change all the species and all biological history . Like abscence of dinosaurs, or mammals, or both - crocodiles rules the world! [Answer] **Will the *Contemporary* plants survive? You're asking the wrong question** In one way the Earth's diversity has dropped over time. We have fewer flora and fauna species. But in another... We have more bacteria, more viruses, than ever before. *And you just dropped all that in the middle of a time where the defenses haven't developed.* > > By the toll of a billion deaths, ~~man had~~ plants have earned ~~his~~ their immunity, ~~his~~ their right to survive among this planet's infinite organisms, and that right is ~~ours~~ theirs against all challenges, for neither do ~~men~~ plants live nor die in vain. (Morgan Freeman, *War of the Worlds* (2005)) > > > The modern flora with all of its disease, parasitic insects, and animal life — everything that could be found within a square Km that's had a bazillion years to develop immunities and symbiotic relationships — would likely thrive in the Cambrian era. Heck, even the Cambrian atmosphere would be conducive (I think) to rapid growth. On the other hand, it's plausible (if not down right expected) that you destroyed the Cambrian era, creating a universe-ending paradox. [Answer] If you read wikipedia, about the last ~ 94MY of [Precambrian](https://en.wikipedia.org/wiki/Precambrian), which is called [Ediacaran](https://en.wikipedia.org/wiki/Ediacaran), and read about [Ediacaran biota](https://en.wikipedia.org/wiki/Ediacaran_biota): * there was little free oxygen before Ediacaran, until all free iron "rusted" * no life on land - even lichens are disputed * even first [insects](https://en.wikipedia.org/wiki/Evolution_of_insects#Evolutionary_history) are from Devonian period, 200MY AFTER Edicarian * several suspected [Snowball Earth](https://en.wikipedia.org/wiki/Snowball_Earth) glaciations. Even if surface is not fully covered by ice/glaciers like during [Marinoan glaciation](https://en.wikipedia.org/wiki/Marinoan_glaciation), it would be too cold for rainforest So chances of your replanted contemporary life surviving back then is slim to none. [Answer] Based on the current understanding of Earth's climate history, transporting said section of rain forest back to the Ediacaran a few million years before the Cambrian results in either the immediate destruction of the rainforest as it materializes in the middle of an ice sheet during the Baykonurian glaciation, or everything except microorganisms dying soon afterward despite missing the ice because of the cold climate. [Answer] **Rainforest plants would do OK. Bugs would thrive!** Long before there were plants on land, there were microbial mats. The heyday of marine microbial mats was well over a billion years ago, with the evolution of multicellular grazers and tunnelers pushing them from dominance. On the land the microbial mats of cyanobacteria and other bacteria did well. There are also fossil traces of these from over a billion years ago. Microbial mats of this sort still do well if they get a head start and grazers are excluded. [Life on land in the Proterozoic: Evidence from the Torridonian rocks of northwest Scotland](https://ui.adsabs.harvard.edu/abs/2002Geo....30..811P/abstract) > > The Stoer Group and Diabaig Formation of the Torridonian succession in > northwest Scotland are late Mesoproterozoic to early Neoproterozoic > (ca. 1200 1000 Ma). Features preserved on the top surfaces of fine- to > medium-grained sandstone beds in a number of stratigraphically and > geographically separated localities are attributable to microbially > induced sedimentary structures; these include wrinkle structures, > remnants of apparent microbial crusts, and indications of original > cohesiveness and pliancy in sand-sized sediment. The surfaces on which > the microbial structures formed were exposed subaerially (abundant, > deep desiccation cracks and locally pedogenic structures) in alluvial, > interfluve, and lacustrine margin settings, and many of the structures > developed in areas well away from the perennially wetted regions > adjacent to shorelines and fluvial channels. Thus, these features > indicate that Earth's biosphere had adapted to and colonized land > surfaces many hundreds of millions of years before the dawn of the > Phanerozoic. > > > There is evidence of [ancient soil and even multicellular life](https://onlinelibrary.wiley.com/doi/full/10.1111/j.1475-4983.2011.01099.x) of some kind dating from the early - middle Cambrian, also before the date proposed for the forest transplant. The [Great Oxygenation event](https://en.wikipedia.org/wiki/Great_Oxidation_Event) had reached its final and current stage by 850 million years ago, also before the described transplant. The atmosphere would be close enough to our modern atmosphere for plants. --- Hundreds of millions of years of terrestrial microbial mats is plenty of time to make good soil, especially in someplace like an alluvial plain that concentrates the rock breakdown products of these mats. Good soil, good atmosphere, water and light means the forest would thrive. But what would really thrive are the microbe grazers and their predators. Springtails, slugs and nematodes would quickly spread over the delicious microbe-encrusted earth. These little grazers would move out from the forest and feast on the defenseless microbial mats. Predators that eat these creatures would also have a heyday. There would be a nice island of forest. The rest of the world would be overrun with bugs until the mats were gone and population crashed. ]
[Question] [ I'm working on a setting where a settlement was established by about 350 people. These were from a medieval civilization, but have been cut off due to various reasons and had settled on the coast of a new continent (uninhabited). It was a shipwreck situation and not a lot of supplies they got from their homelands survived. They have however survived for a decade now and have a functioning village slowly develop with the basics of food, water, and shelter covered. They hunt/forage/fish and supplement it with simple crops/farming. Early on, one can assume they would be living as a community but as time passed, they would barter goods and services. However, I need to figure out how they would setup money based economy? Since the generation that experienced civilization are still surviving (since only a decade had passed), they have knowledge of money based economy. How would they go about establishing this? [Answer] Money economy does make sense when there is the need to exchange good and services over large spatial or temporal intervals, where money act as non perishable value keeper, to be used when barter is non practical (e.g. I would barter 2 cheeses for your ladder now, but presently I have only 5 goats and making cheese would take me 3 months). Normally in your situation once they settle their village some of them would start venture into the surrounding for hunting and gathering water and other resources. This would result in exploring the surrounding and establishing paths. While doing so they would end up either crossing some already established commercial routes or finding some other village. But you state the continent is not populated. There is then no need for a value keeper which is non perishable. I even doubt if they will need to keep the concept of private property. Unless they grow so much that they can spread in the continent, creating different villages with different needs and productions (e.g. a village of farmers, producing crops during summer, and a village of hunters/sheperds, producing meat/furs during winter) [Answer] One thing I've read is that the development of money seems to predate the development of currency by many thousands of years. In other words, there wasn't a free-for-all system of barter, where anything could be exchanged for anything, but a few semi-standardized units of value, such as livestock, which were later replaced by tokens. [Origins of Money and Banking](http://projects.exeter.ac.uk/RDavies/arian/origins.html) So, your society might have decided that cows and chickens are your main stores of value and exchange. Not quite the same thing as pure barter. Another possibility would be a gift-based economy, which is similar to barter but not identical: [The Myth of the Barter Economy](https://www.theatlantic.com/business/archive/2016/02/barter-society-myth/471051/) [Answer] As was brought up by Ariah, a true barter system has never really been observed, even in very undeveloped parts of the world. People tend to implement the closest things to barter systems in time of need (winter, famine, etc.), or when communities are extremely small. Often, however, it's usually more of a neighborly, gift-based system. Now, you have stated that you want your community to move past a communal, gift-based, bartering society, which is really quite natural. I can see it going in two directions, one without money, and one with money. In this case, I determine money to mean a medium of exchange that holds "imaginary" value. A banknote is not actually worth 20 dollars - its literally a piece of paper - but the society gives it value. # Without Money Now, in a stable environment, often several goods naturally become a sort of currency among a people. They generally meet a few criteria: * Non-perishable (I use this term loosely) * Plentiful * Stable in value Depending on the environment, a few common examples would be cattle, rice, blankets, salt, skins, tobacco, and wine. All of these never really lose their value (okay, cattle can die, but they're pretty stable), are useful, and, in the areas where they were used as currency, were generally pretty easy to come across. Things like bread, or eggs, that will go bad extremely quickly, are less suited to this system, and things that fluctuate greatly in value (because of seasons, for example), are generally unsuitable as well. This would be a more natural evolution as the society moves on from struggling to survive to a more normal state of existence. Without external influences, this is the most likely development to occur. # With Money Well, we all know how money works. As for materials, you can be as creative as you want. Whether its a seal printed on paper, minted coins, bits of precious metals, shells, et cetera, you can really choose anything convenient for use as your currency. "Why would such a system develop here though?", is the imperative question. Frankly, it wouldn't be completely necessary. It is quite plausible, however, mostly due to the cultural background of the settlers. If they came from a nation with ideas of money engrained in them, it is quite likely that they would mimic their native culture. # Somewhere in Between Most European colonists (which seems to be the closest approximation to yours), used a mix of the two. In early Virginia (Jamestown and Roanoke), copper, tobacco, and minted coin were all used as currencies. Most emerging societies will find themselves in between as well. [Money, Credit, and Banking in Virginia, 1585-1645](http://economics.yale.edu/sites/default/files/goldberg-paper.pdf) # Establishing a Money-Based Economy Establishing a money-based economy is fairly simple in theory. The government decides upon a value to give to the currency and makes the currency. The hard part comes in convincing everyone to act in accordance with the idea. It could be difficult to convince someone to trade a cow for a piece of paper at the start. As time goes on, however, and if the money stays stable (no horrible inflation or deflation occurs), the society will start to have more and more confidence in it. It certainly will help that all of the settlers came from a society where money was the norm. Money, at the end of the day, is a risk, with rewards. It has no inherent value, but allows for much more ease in trade and regulating the economy. [Answer] You could chalk up developing an 'economy beyond bartering' for an isolated village to a number of things (summed up at the end). First, you could look at different forms of pristine state formation and extrapolate the consequences of each one. F. Fukuyama listed six in a book called Origins of political order. I'll mention two: A Hobbesian model, whereby everyone lives in squalor and barbaric conditions until a hierarchy is developed and a king (or priest, in those days) claims there must be a better system and says the way this will be is through gold or grain. Hierarchy allows a ruler to manage the population better and the one on top says how its all going to be. Hobbes called it the 'Leviathan'. The ruler in turn can claim more for him self and the population lives is stratified. An alternative is by a guy called Ibn Khaldun, (14th ce) who argued something that the book Dune adopted. There's a people that comes up from hardship by settling down and becoming farmers, and there's a nomadic warrior people living on the fringes. When the farmers become soft, the warriors come in, kill people and force them out and then sit at their tables becoming soft. (The original people become nomad warriors and return years later when they've become stronger than the new farmers. Kill Loot Repeat) In this way, an economy is born by becoming more comfortable and advancements that take place to make people lazier. To create this kind of advancement-decline-repeat system, some people leave the village to venture forth and do their own thing - become disenchanted and return. Personally, I think there's something to be said for urban development. The Oxford Handbook of Cities in World History claims in the early chapers that it's a mistake to think that a bartering system changes because there are more people. Rather, it changes because with more people, new institutions rise to manage them in different ways. Old european cities usually had multiple tiers of problem solving levels. For example: a town would contain a number of streets and in a street there was one guy you needed to speak to if something went wrong (like theft). If he couldn't solve it he took it to e.g. the church. If they couldn't fix it they took it to the courts. Which is why today, depending on your problem, you can call support centre, next go to the council, next go to lawyers office, next go to police, next go to parliament or something. A bartering system changes when the problems facing the people overwhelm whatever system is in place. In short, 3 ways: the economy (a system of exchanges and interaction) changes when a hierarchy is instated that says: 'this is the way we will do it now'; kill-loot-repeat system that sees people pursue peace through comfort and death; or system changes within urban setting that try to reconfigure the way it's done (progressive trial-and-error changes). Just some options. [Answer] Money would come into play when the leaders decide they have a need to tax the population. If the rulers create the currency, it gives them more control over the population and makes taxing them easier. ]
[Question] [ This has been a burning question of mine for many years: [If magic is real, can it be true that rational scientific thought should exclude it?](https://worldbuilding.stackexchange.com/questions/13364/if-magic-is-real-can-it-be-true-that-rational-scientific-thought-should-exclude) In the course of discussing it, I've realized I need to address my expectations more directly. This passage is from a post by user Qi Chin as part of the pitch for a WIP steampunk fantasy RPG on the defunct [indie-rpgs.com](http://indie-rpgs.com/archive/index.php?topic=23104.0;wap2). I love it even more now, as it summarizes what I'm aiming for better than any words I could write: > > The oppositions of the three pillars the world is set up on: > Technology, Religion, and Magic. Each part is needed for everyday life > to go on, but these three aspects keep opposing each other. > Characters either act either as agents of one of the three aspects > (mercenary or idealistic) against the other two, or as agents of > balance > > > I cut it off at this point because it then drifts toward emphasizing religion and losing the parallelism. Anyway, I want to make a world where this makes sense. There are three (what is the best word?): Science/Technology, Religion, Magic. Each corresponds to an aspect of how the universe works. Each requires a different mentality and worldview to fully grasp. This is the contradiction: they are, or at least appear, contradictory, yet they are all equally right. And not by being equally wrong: I don't want the story to be anti-science or anti-religion, nor do I want to have to make all characters be wrong. All three pillars are equally important. But what does religion give? Science is related to technology, magic also lets you manipulate the world, so what can religion grant to devout practitioners that's equally concrete yet doesn't fall under the other two? I detect a Christian fundamentalist assumption underlying the structure I want, and that raises the question: **Can I make a world that maintains this three-pillar structure without the story only making sense to readers with a strongly religious worldview?** I want all pillars to be equal within the story; it wouldn't seem right for that equality to only exist if viewed from the perspective of one specific pillar. Said assumptions that seem fundamentalist: * Science and religion are intrinsically opposed. This is most evident with religions that focus on dictating aspects of nature. * Religion and magic are intrinsically opposed. Only makes sense with religions that prohibit what they term "magical practices", which naturally excludes any of their own practices. I don't want readers taking a D&D approach: "That's Arcane Magic and that's Divine Magic." All magic must be arcane (whatever exactly that means in this context). The third side of the triangle may not directly stem from fundamentalism: * Science and magic are intrinsically opposed. As seen in my previous question, they do seem to be opposed, in the sense that it's difficult to define a world in which magic can exist and not be subsumed by science. I require them to be opposed in a more straightforward sense. This seems to imply the popular phrase "Science is the religion of our time", a description that often bothers scientists. But this also seems specifically religious: * There can be aspects of the world that appear (or are!) contradictory yet are all true. So how do I reconcile all this? I recognize that I can get close to what I describe by appropriate choice of prevalent scientific, religious and magical views, but I was hoping for more. Ideally, there would be some characteristic of this universe that made this conflict more... philosophically justified? than it would be in ours. [Answer] Instead of taking the philosophical groups *Science*, *Religion*, and *Magic* and facing them off against each other - frame it about the conflicts between the people within those groups. **Magic vs. Science** If you consider [Clarke's Third Law](http://en.wikipedia.org/wiki/Clarke%27s_three_laws); > > Any sufficiently advanced technology is indistinguishable from magic. > > > Then science and magic aren't really in opposition. Science may be unable to explain it, but it isn't *opposed* to it. Magic, like Science, doesn't have emotions. It doesn't care if something else is opposed to it or not. However, *people practising magic* - let's call them Mages - very well could feel threatened by the ever-advancing march from the scientific community to *explain how things work*. I mean, it does take the fun out of things! Conversely, fans of the scientific method may not understand or appreciate why Mages do amazing fetes with reckless disregard for the minutiae of it. An interesting angle to consider would be if [Scientism](http://en.wikipedia.org/wiki/Scientism) was a common philosophical view in your society. **Science vs. Religion** Religion, to a large degree, is instruction on *what is - morally - right and wrong* and how to behave. Science doesn't really have any moral code - it's amoral(not immoral). There is no good nor evil - there is only nature to observe, study, and understand. In that sense, Science and Religion aren't explicitly opposed either. To have opposition between religious people and the scientific community, the prevailing religion needs to have a doctrinal opposition to understanding how God(s)'s universe works. Creation could be seen as sacred and study of it degrades it to a level where *mere people* can understand it. The phrase *God is a watchmaker* definitely should be considered heresy. On the flip-side, a religion that is a-okay with science may see it as an opportunity to gleam insight into how awesome Creation is, and further evidence that God(s) is worthy of worship. **Religion vs. Magic** Again, opposition comes down to views and beliefs people have about magic. Mages could plausibly hold the view that *"Hey, magic exists, why shouldn't we make use of it?"* Whereas a religion may say that practice of magic is witchcraft. Your religion could take a more mild view. Consider the Jedi Religion and The Force - with its respective light- and dark-sides. There are some aspects to magic that are benign or even beneficial, and there are some aspects that people should meddle with. Compile lists of good-magic and bad-magic, and you'll find lots of differing views and lots of room for large culture-wide opposition. **TL;DR.** > > Can I make a world that maintains this three-pillar structure without the story only making sense to readers with a strongly religious worldview? > > > Yes, I think so. Each group has its own fundamentalist elements. Be sure to point them out, and contrast them against more moderate views within each group. [Answer] > > But what does religion give? Science is related to technology, magic > also lets you manipulate the world, so what can religion grant to > devout practitioners that's equally concrete yet doesn't fall under > the other two? > > > Traditionally, religion has offered many things that can't be obtained through science or magic (at least, the sort of "magic" that people have actually believed in in real life; fictional magic is a bit different). **Community**: religion is usually an element of a community rather than a single individual. Community elements of religion may involve: enforcing social mores, helping members of the community in need, uniting the community against an external hostile force. Science also involves a community, but I feel like scientific communities are not usually quite so tightly bound as religious ones can be. And magic, on the other hand, seems more likely to be a personal or at least secretive endeavor. **Moral Code**: religion often is associated with a moral or ethical framework that may motivate the adherent to self-improvement, or to serving an ideal such as "helping others" or "breaking free of the ties of the world." Science and magic are both more mechanical, providing means to achieve results (the "how"), but not providing a value system by which to decide "what" to do. (By the way, I'm not saying that scientists or magic-users lack morality. Of course, they have their own moral systems. In real life, scientists and people who believe in magic can formulate systems of ethics based on multiple sources, including philosophy and religion. In your world, apparently no scientists or magic-users are religious(?), so their codified systems of ethics would have to be based on non-religious philosophy.) **Miracles**: a "miracle" is a bit different from magic. As I said earlier, magic is generally a fairly well-defined "process" for using mystic powers to achieve some result. The magic-user says an incantation, or brews a potion. A miracle, on the other hand, can't be forced. It is the result of intervention by a higher power. A follower of a religion may pray for miracles, but can't demand one. (There is of course an exception: the standard rites, blessings or sacraments that may be associated with religious clergy are generally formulaic and have predictable results, but at the same time are not considered "magic".) [Answer] From your comment: > > Answering "Can people act like this?" is not sufficient. I want "Can there be a (meta)physical difference in this world that makes it more right for people to act like that, with 'right' in both senses of true and good?" > > > This actually lends itself very well to a very simple explanation. ### Science vs. Magic For the most part, the world behaves exactly like our own world does. This allows the scientific method to be applied (to most things), which allows for *true* science, as well as the trappings of science that you were probably referring to - like inventors, steam power, and labcoats. Magic, however, cosmologically rejects investigation. Magic that starts to become "understood" doesn't just cease to be magic, it ceases to work *at all*. This makes mages very paranoid and causes them to at the very least avoid or hide from scientists, and in some cases outright kill them. Mages who trifle with such things as the "scientific method" are hunted by their peers, because they're literally endangering all magic. Magic is only taught through apprenticeships, because every mage is a little bit different and the act of learning magic well enough to write a textbook about it or teach it to a classroom would destroy it, or at least destroy the parts the mage intended to teach. ### Magic and Religion Once again, since Magic is the thing that we can most easily change, I'll assume religion works similarly to our world and change magic to make them opposed. In addition to being impossible to understand, Magic is inherently evil, or thought to be so. Have some calamities in history been caused by mages who got too powerful or too greedy, though in some (true or not) conventional wisdom about how magic inevitably corrupts the user to great ambition and selfishness, and you've a recipe for any sensible religion (or secular authority) to ban its practice. ### Science and Religion In the real world, there are religious people who are also scientists. While science - that is, the scientific method and the philosophy that has grown up around it - does reject blind faith (through concepts like Burden of Proof and Occum's Razor), this divide isn't as deep as the two that involve magic. That might be fine. If it's not, you need an unambiguous statement from the religious powers-that-be (either God(s) or mortal heads of churches) that the world is meant to be appreciated, but not examined. [Answer] The proposed situation requires three distinct spheres, none fully comprehended – in either sense of the word – by the others, individually or in tandem. For the sake of argument, let’s presume that “science/technology” resembles its correlate in our world. The question, then, is how to construct the other two poles. **Religion** As noted [elsewhere on this site](https://worldbuilding.stackexchange.com/questions/824/is-there-an-effective-way-to-design-a-realistic-religion-for-a-world?s=1|0.9702), the common, vague set of presuppositions most people in the West ascribe to the category “religion” are extremely problematic. They do not effectively describe most religious phenomena in human history, and they take as normative a set of Christian theological notions, largely arising from the Protestant Reformation. The result is that all “religions” are presumed to be Protestantism in funny hats. If you want to begin with the assumption that “religion” is a genuine, legitimate phenomenon in the world, and it is not entirely dependent on such Judeo-Christian notions as “faith,” then you have a phenomenon that *can be studied scientifically* but which *cannot be falsified*. This is extremely important. To whatever extent “religion” makes falsifiable claims, they must be presumed incidental to what the system provides its adherents. As Émile Durkheim put it, “No human institution can rest on error or falsehood, or it could not endure.” The core principle, I suggest, is that “religion” is a phenomenon that binds together social groups and causes them to adhere to and obey abstractions rather than individual desires. Ordinarily, these abstractions are projected into the metaphysical or super/supra-natural. Within a fantasy context, it makes little intrinsic difference, since demonstrable supernatural effects can be analyzed from a scientific perspective, drawing them into the realm of the putatively natural (though see below, on magic). What science *cannot* do is to demonstrate that the abstract, metaphysical claims of religious adherents are simply true or untrue. They are not reducible in this way. To take an obvious example: does the American Flag represent the United States and the people who consider themselves Americans? That’s not in itself an answerable question. What do you mean by “represent”? And yet it is precisely *without* such refinements that the flag gets so hotly contested (flag-burning amendments, etc.). Insofar as the abstraction functions within the socio-religious context, it does so at an immediate, doxic level. Example: are American flag stamps patriotic? Lots of people think so, including the US Postal System, but they do in fact violate several articles of US law regarding flags and their display. Does that matter? In what sense “matter”? Some will object that this is patriotism, not religion, thereby demonstrating that they’ve missed the point, but let’s allow it for the moment. Consider Lynch v. Donnelly, the “Pawtucket Crèche Case” (see Wikipedia or whatever for references). In essence, the city placed a “holiday display,” including a “holy family crèche,” on public land. The city said that they did this to bring people together in a positive spirit and prompt them to spend money at the mall. The Supreme Court ruled that this display was not religious, because it was really about money, and therefore secular. But in what sense is money or economics intrinsically secular? If people gather annually and are compelled to use money to designate a complex system of obligations (e.g., “think of the homeless at this time of year, please give”—should we not think of them at other times? Why the obligation only in this season?), and if infinite TV specials and whatnot insist that money is not what’s really at stake in all the monetary exchanges, then isn’t money the underlying material symbol of the holiday spirit in the US? Returning briefly to the tripartite division in question, we can see here that a scientific study (such as Durkheim’s) of a religious system is perfectly possible, but it in no sense *comprehends*, much less *explains* or *explains away* that system. It offers a translation from one system of knowledge to another. **Magic** As a rule, terms cognate with the Latinate “magic” (*magia*, etc.) function largely to designate minority, small-scale, or despised ritual phenomena. At the same time, *magia* commonly designates the study and manipulation of phenomena outside natural-philosophical expectation. For example, in the high Middle Ages, the study and use of occult (hidden, infra- or supra-natural) powers was divided into *natural magic* and *demonic magic*. *Natural* magic examined real, identifiable phenomena whose mechanisms, though occult, occurred without the intervention of intelligences. For example: magnetism, sympathetic resonance, astrological influence. *Demonic* magic concerned phenomena whose causes lay within the power of intelligent, non-human beings (demons, devils, elementals, angels, etc.). From this perspective, focusing on the “natural,” we can further divide phenomena into those whose mechanisms are knowable but as yet unknown, and those whose mechanisms are intrinsically unknowable because exterior to nature. To understand this, you must recall that “nature” in the Middle Ages meant the sublunary sphere, the world beneath the moon. All powers superior to this, from the moon to the stars and on to the empyrean, simply could not be interpreted fully, because they were not subject to natural law. In many understandings, such phenomena as magnetism manifested celestial (moon through stars) power within the sublunary. As such, their causes could not be codified or understood properly within any scientific system. Their study and manipulation was therefore intrinsically magical. You may say, however, that this simply divides “science” arbitrarily into two sectors. This is not entirely the case. If we postulate that a range of phenomena are caused by suprahuman intelligences—gods, angels, etc.—then scientific study may not be useful. Each phenomenon of this kind would be unique, dependent on the intelligence in question, responding to the investigator’s own spiritual qualities. One could never reduce the variables and factors sufficiently to develop controlled experiments that could yield worthwhile results. (They’d work, but they’d give only negative results.) So their study, while theoretically possible from a scientific perspective would be irrelevant and pointless. **Religion and Magic** There will likely be some conflict between these, insofar as magical study seeks to manipulate the powers that undergird human reality. At the same time, this conflict is not intrinsic. From a common early modern (late Renaissance) perspective, the serious magician cannot achieve any higher knowledge of celestial intelligences without their approval, and as they are of the angelic orders, that approval is a kind of divine sanction. In other words, magic only proceeds effectively if the magician fully submits to the deepest personal sanctity. This is not to say that his work will put him in a strong religious position institutionally, only that he need not be a pariah. Similarly, there is no particular reason that priests or whatever should find him especially threatening—nor that they should take much interest in his results, since after all they have nothing to do with how anyone but he can or should live. By this construction, these systems certainly overlap, but at a practical level they need have little to do with one another. **Conclusions** There are many other possibilities. I sketch this rough western-European system because (a) I know a lot about it, and (b) it’s easy to research. But it should give you some ideas for how to develop your own system. The crucial point, as I see it, is to recognize that these three spheres do not intrinsically have much to do with one another. So long as you maintain that at a logical level, you can readily invent all kinds of conflicts and twisted alliances made at the *human* level. In other words, the vast complexities necessarily arising as these many institutions and groups and individuals come together have nothing to do with what *must* happen, and everything to do with ordinary human politics and so on. [Answer] These three are different ways to manipulate the world. **They each are a tradeoff between the power of the effect vs certainty of the result.** Science is repeatable if you conduct the same experiment thousands of times it will always to the same thing. But Science is constrained by the laws of entropy conservation of mass and energy and the laws of causality. Very reliable but the least powerful. Magic is a bit more temperamental. The mind set of the user matters and it is a bit more chaotic, 9 times out of 10 the same spell will do the same thing but there are some odd ones. Magic can break through some of the limits on science, teleporting breaking conservation of momentum, and causality fireballs violating conservation of energy and so on. But magic in turn has limits you can't raise the dead you can't move continents and so on. Magic is stronger but not quite as reliable. Religion is talking to / negotiating with a higher being. It is very hard to predict what will happen. Asking for the same thing might result in a different result every time. But the results can be awe inspiring, the dead rise the sun stops in the sky, and planets come into existence, there is no known limit. Religion is the least predictable since you are talking to a wise being rather than invoking rules, but it can have the most powerful results. Each of the three fields will have their own ways of trying to improve repeatability and power but these are the starting points. [Answer] In the cartoon "Gargoyles", one of the characters makes a very profound statement to his employer (a Tony Stark-like fellow) who is about to come under attack by Oberon, the King of Fairies. "Energy is energy," he says, "No matter if it was created by magic or technology." Obviously, you can't create or destroy energy, but this is a cartoon. Even so, the point the character was making rang true for me. Now, beginning with that premise, we can define terms: * Science: Science is a process. Observe, hypothesize, experiment, analyze. * Technology: The use of science in the physical world to harness the energy around us, from the simple machines (wedges, levers) to the most complex. * Magic: The use of science in the metaphysical world to harness the energy around us, from the simplest spells to the most complex. What does this leave us with? Magic and tech are truly two sides of the same coin; magic may seem to have some complexities, but really, this is why they have schools dedicated to the subject. Not everyone can be a wizard just like not everyone can be an engineer. Now, religion is more interesting. You're not manipulating any energy. You're not even holding a device (chainsaw!) or enchanted artifact (Dreadblade of Eternal Fire!), you're holding a thing that represents an idea. In a world where people can use such things, it would be difficult to gather followers unless you can do something about them. By allowing your priests to invoke your power (assuming you have any), they can draw energy *from you* to do whatever it is they need. Since you're a deity, you can extend that to whomever you like, really, but concentrating it with the people that have dedicated their lives to you is typically a good idea. Unless you feel like monitoring everything constantly, you can set up certain restrictions on how your powers can be used. These would be my guidelines for a world with all three. [Answer] The best technique you can use is to recognize that the world is not homogenous, and the three pillars are not just standing idle trying to prove things. They are actively trying to change the world such that they eradicate that which is not **easily** explained by their approach. Accordingly, if there is a region which is heavily dominated by religion, it will seek to craft the world in a way which is best understood by religion. It will make sure that it is hard to bring deep magic or deep science into its hallowed corridors. The same goes for both science and magic. Any force powerful enough to claim to be a pillar of a world is going to be shaping the environment to make its way of thinking more powerful. There will be contradictions. These contradictions will occur far from the centers of any of the three pillars, in the murky realm between it all. All approaches will treat those contradictions with disdain (for they make sense in no mindset). Ignorance of these details balloons into expenditures of effort to deal with the consequences of that ignorance. Now, as for the smaller question, of what does religion bring, if one wishes to avoid directly empowering religion with being "right" (as in "they picked the right deity"), one power they have is the power of tradition. Religions are astonishingly good at developing individuals whose mindsets are deeply rooted in ancestral beliefs. This can be even more so than the effects of magic (though magic does love family blood lines). Let this be their power. The religious institutions would naturally have great gestalt powers forming from looking at the religion as a whole. A religious warrior can fight with a fury unmatched by science or magic because he or she **knows** there is an afterlife. From a gestalt perspective, the common core shared by all those of that religion is the part of value, so losing a body is just that... a body. Magic and science place more value on the individual, so the loss faced by a single individual is much greater. [Answer] One possibility is that this society exists within the context of much more powerful neighbors (going with the magic-is-science angle). These neighbors are unwilling to share technology explicitly (hence, the scientists have to work hard), but will do so under some conditions (hence, magic is the result of using powerful artifacts provided by the outsiders). Under some conditions, the neighbors will intercede directly; but they are powerful and vain and like to play god, so require tribute and offerings (religion is the way this society requests divine aid). The scientists believe that society needs to be self-sufficient, and thus is always pressing to advance native knowledge. The mages believe that the way forward is allying with the outsiders to make leaps and bounds increases in power. The priests need neither science nor artifacts to achieve their goals, since they can simply invoke divine powers to do all the heavy lifting for them (some of the time). The neighbors themselves are stratified into many camps. The non-interventionists believe that all creatures must earn their own fate, and thus stay out of the affairs of the more primitive society (but look admiringly on the scientists). The traders recognize that the primitives will advance eventually anyway, so positioning themselves in favorable trades will gain them the upper hand. The aristocracy is bored and has no real obligations. Playing god comes naturally to them and plays on their vainglorious narcissism. They must let the primitives suffer from time to time, to maximize their need for the "divine". But they personally intercede at critical moments to ensure that the faithful are justified in their prayers and praises. The balance of the primitives may reflect the balance of the advanced, or could be totally independent of it. For instance, the non-interventionists may be the most politically powerful, but simply not care about the actions of the other factions. Or, the advanced factions could all be vying for control, and using the primitives as their proxy. [Answer] Easiest way to reconcile the issues is to start from clean board and focus what you actually want. While magic is not relevant in the real world all conflicts between religion and science that I have seen are based on ignorance of facts on the part of the person who sees the conflict. Ignorance of facts here does not mean ignorance of science. A surprising number of devoutly religious people do not really understand the religion they follow and, oddly enough, many atheists insist on baseless beliefs about religions. Even more odd is that those baseless beliefs are usually based on statements and opinions of people the atheists otherwise think of as idiots. So it is good to ignore most things you know about religion versus science from the beginning. Although [Bahá'í might be a useful reference.](http://en.wikipedia.org/wiki/Bah%C3%A1%27%C3%AD_Faith_and_science) I'll give my own suggestion below. Note that it reads much like some sort of an utopia. This is more or less inevitable for rough outlines of drastically different societies. You'll have to insert your own issues and conflicts based on the needs of the story. **Religion** could be mapped to normative control. And in fact that is the main social purpose of religion. Basically the religion would serve as a guideline for determining what behaviour is socially acceptable and what is not. Clergy would work as organizers, teachers and interpreters of moral code. Note that moral codes do **NOT** deal with good and evil, they deal with social norms. The two should always be connected as closely as possible, with the ethics informing the moral code and its interpretation, but forgetting the distinction leads to direction of influence inverting. Which is a problem since social norms are affected by current politics and cultural prejudices. Thus inversion invariably results in the persecution and even murder of minorities being considered "good". And persecution and rejection of opinions your social group disapproves of. Which is not really compatible with the premise, so the people of the setting should be well aware of the distinction. Science actually studies ethics, generally with more objectivity than religion can, so questions of ethics would probably be dealt with science. Actually applying them to matters of morality would be a matter of religion. Religion also upholds traditions and rites promoting social cohesion. **Science** would deal with remunerative control. Basically, economics, production, commerce, employment would be planned, controlled and developed based on science. This would include matters of ecology, health, transportation, and other issues that directly affect economy. Regulations and their interpretations would be experimented or simulated, the effects would be observed and analyzed, and finally changes that would improve achieving the goals intended would be implemented, others not. What those goals should be would be a matter of social norms and actually fall under the direction of religion. This would give science and religion a stable and mutually beneficial two way interaction. Science is also vital for education and collecting information all decision making relies on. **Magic** would deal with coercive control. Violations of the moral code and economic regulations would be investigated and prevented with magic. With mind affecting magic offenders could be reformed with much higher success rate than prison sentences or fines can provide. Matters of internal and external security would also be dealt with magic. Magicians would naturally be subject to moral code and regulations as normal. And obviously be part of the society and economy in general. They'd have wages and equipment built with science. Deal with moral dilemma by turning to religion and possibly their confessor. Combined with the role of magic in enforcing proper function of science and religion this should give a relatively stable three way interaction. [Answer] It's interesting that you explicitly group science and technology, as most (all?) real-world fundamentalist believers have no trouble using all the technology they please while denouncing the methods and ''beliefs" that make it possible. By keeping the terms and ideas explicitly linked, perhaps through language, it will be clear that you can't use the fruits of science without *some* form of acceptance *of* science. In [another recent Answer](https://worldbuilding.stackexchange.com/questions/8/must-magic-be-tied-to-medieval-tech/17178#17178), I suggested that if physical law were teleological, an attempt to understand physics would be more like psychology or politics. It would have more in common with Madison Avenue than Mathematics. So, what if *some* physical law is like our real universe, understandable through clear rules that operate at the most fundamental level of the constituents; *and* some rules that are teleological. Perhaps some lost civilization or alien über-technology, back doors into the simulation, feral AI nanotechnology, aliens that watch them like a telenovella and *do* interfere (essentially making the ideas of Greek gods real), or other excuse for making the teleological stuff exist "on top" of the essential fundamental physics could be explained to the reader, but would not be understood by the characters. The basic premise of science that rules are defined at the most fundamental level, are simple, and absolute would not be held as an inviolate principle even by the followers of scientific method, because *some* things act like human-scale concepts and whims are at play. Careful experiments might get messed up through magical interference (nanobots contaminate *everything*; the "gods" just want to mess with you) so the absoluteness and confidence might be iffy as well. A mage who successfully controls or predicts some aspects of reality will work with squishy concepts at the scale of humans and tied with human perceptions. it will be like our *economist* not like the science camp's *physics*. So why can't they co-exist? As I pointed out, even the hard core scientist will admit the limitations of his field, as part of the mindset of the science camp. Maybe they suspect that the teleological stuff is built on top of the fundamental and don't appreciate the size of the gulf to bridge them, and feel that the messy stuff will yield to clear rules with enough data and better math. Maybe they compete for funding and market share. Ah, what if they interfere? Like I mentioned above, experiments get messed up by magic influences. Nanobots in the reagents and glassware get activated if "magic" is used nearby. The same would hold for commercial applications. So, your electronics would go haywire if brought into a household where all the appliances and comforts were based on magic. **A household would be strictly one or the other, beyond the most robust physical "simple machines".** The magic camp could be criticized for its lack of reliability and applications that it doesn't handle well, especially in the emerging Industrial Revolution. Towns set up around (steam based) mining operations will have strict rules to keep out any magical interference. Embracing one fully means giving up the other completely. Now what about *religion*? In your scenario it needs to correspond to some aspect of how the universe works. How does that translate into a way of predicting outcomes and providing increased prosperity and comfort? To make it approachable to readers other than (this culture's) fundamentalist, it needs to depart from the normal meaning of *religion* as opposed to evidence-based reasoning and positions that can't change with better understanding. I'd suggest making it completely different from Abrahamic religions in our world, so it won't be seen as being something to appeal to the real-world religious. It does follow that the teleological "magic" rules which can be exploited must have some kind of *Agency* associated with them. It needs a backing intelligence to handle the human-scale and human-perception concepts. A camp could exist that addresses the intelligences directly and explicitly, rather than as a set of rules to exploit. In that world, it might not be so clear that teleological rules require agency and backing intelligence. Perhaps the human perception just matches the real underlying universe-backed concepts, as they naturally would. So what would this camp *do* that conflicts with the Mages? We need to assume that it clearly *works* and this is acknowledged by all camps. If the R camp addresses the Agents directly maybe they are opposed to M's "technology" from exploiting the rules directly. Use of M devices in an R household would interfere with the natural balance they are trying for, to let the gods like them personally and care for them by arranging things to turn out well for them. R people have a complex magical environment around them that is messed up by directed specific use magic, and the unreliable and iffy M applications are *certain* to go wrong when in an R environment. R people need to avoid S technology too because R works when people are *not* taking direct control over aspects of reality, beyond a certain (historical) level. Their lifestyle would be rather different. But they are "successful" in being prosperous, healthy, and happy. Maybe they are against the other two camps encroaching on more of the natural environment and their homes in the wilderness. And the gods take care of them, right? So someone encroaching on their territory in order to mine the land, change it to farmland, or whatever, will run into troubles. In the modernizing world that trouble might amount to both S and M devices not working so well for them, and bad luck caused by M influences. That means that a steam-tech enterprise encroaching on them is doomed. R people might also push the other way, where the whole R society pushes others *out* or stops them from taking on something new that the R people think is wrong. --- > > All three pillars are equally important. But what does religion give? Science is related to technology, magic also lets you manipulate the world, so what can religion grant to devout practitioners that's equally concrete yet doesn't fall under the other two? > > > I think it's still not clear, so let me elaborate by choosing a more specific scenario. Let's say that the distributed AI of the nanotechnology is supposed to "take care" of the whole of the environment including the primitive tribes of sentient beings that lived there, at the time they were deployed by benevolent aliens to prevent the planet's demise by natural means like a "great dying" due to something or another. Using M *directly* messes up the overall system, and when such use is respected and allowed does prevent the overall system from doing its normal job. People have taken direct control over their environment as civilization progressed, and the overall nature-keeping system is overridden and broken everywhere people started doing large-scale things and as they learned to be heavy-handed and direct M to their own personal small-scale goals. The R folks want to keep things the old way, and find benefits that "civilized" people have lost. They live in simple huts but tolerate the weather magically without having to explicitly control the environment in their hut. They hunt and gather, always finding enough and never facing hardship. They don't get sick, and find disease and pain to be the sickness of the city-builders and proof of the correctness of their ways. Educated people who have returned to then R lifestyle find it boring and miss more explicit comforts, so they have turned to an explicit worshipful philosophy and apply themselves to artistic endeavors. All the good music and paintings come from the R, and people go on retreats to them (sometimes to stay for good). [Answer] Things religion could contribute that science and Magic could not: 1) a moral system. Science can only tell you how things work, but not if they're moral or not. Or as Hegel puts it, you can't derive an "ought" from an "is". You could make the Science people (and the Magic people) use their technology / powers to do something that the religious people would find morally abhorrent. Then, religious people would be distrustful of everything Science and Magic may offer, for they would think of Science and Magic as paths to immorality. 2) Connection with a higher being / god. This is the purpose of religion. The word comes from Latin religare (to reconnect). Maybe humankind may have sinned against the gods and so lost their favor. The only way to reconnect with them is through religious practice. Now Science and Magic may be forms that your humankind has found to live in a godless world and survive on their own, without resorting to higher supernatural beings. But since Science and Magic try to harness mankind's own potential, without relying on gods, then there would be no way that Science and Magic could unlock the god's power. This means that the gods must be above the scope of scientific experimentation (ie they must be non-physical and unbound by natural laws). Also, they must be personal beings (i.e. not just some kind of impersonal force or energy to permeate the universe) to answer prayers and do miracles. By doing so, these gods would only answer prayers if they saw it fit, so they couldn't be manipulated by the Religious people. So religious people wouldn't have the gods at their disposal as a kind of freak show to convert the Science and Magic peoples. Only people with faith and that adhered to The Religion would be able to reconnect with the gods and be able to talk with them in order to get prayers answered. Mind you, this doesn't mean the gods would be real. Just that the perspective of the religious people regarding reality would be so. 3) Regarding Science and Magic, they both may harness powers dormant on the forces of Nature. But they would be opposed as the scientific method is to some kinds of practices based on empyricism (it works and I don't know why). See the difference between Western Medicine (based on scientific method) and practices like Accupuncture (based on empyricism). [Answer] I see your three pillars and I can see how you can make them work without leaning too heavily on one thing or another. The First thing is to take it as a given that the three pillars are the corners of a contiuum. The hard core are going to be closer to one pillar or another, Fundamentalists on all sides are going to be inclined to reject the other 2 pillars. So lets look at what each Pillar represents: **Religion is Faith**. Things happen because God wills it. Things fail to happen because God wills it. Most folks will understand that science and magic have their place, but your fundamentalists around this pillar view these as a Denial of God. After all, miracles happen, right? **Science is Logic**: We can breakdown and understand everything. We can get results by consistently applying the same set of conditions. The Fundamentalists around this pillar will claim there is no room for Faith or Magic, or that they are irrelevant. Miracles are just a series of highly improbable events. **Magic is Intuition**: An application of mental will, and stuff happens. You don't have to consistently fill in all the dots to get a feel for how things will play out. You bring in the variables by feel, account for the chaos of the universe based on experience. In a way, there is a blend of the other two here, you have to have faith that the magic *should* work, and there are semi-consistent steps to take for a desired result, but those steps can vary by individual. Our will and intellect make things happen. Fundamentalists here are going to say Chaos is far more powerful than limits imposed by science, and our will is as powerful as that of any god. All three of these can be combined in various ways. Magic could be studied by the scientific method. Miracles can be wrought with magic, and Science can be used for examining God's works. It sounds like a foundation for an interesting setting [Answer] # They are *always* mutually exclusive * **Science**: Stuff happens, and I know how it works * **Magic**: Stuff happens, and I do not know how it works * **Religion**: Stuff does not happen, but I know how it works anyway * **Chaos**: Stuff does not happen, and I do not know why These things are mutually exclusive. Once you have figured out how magic works, it is no longer magic but science. Once you have figured out why religious stuff does not work, it is no longer religion but science. Once religious stuff to work and you do not know why, it is not longer religion but magic. Once you lose the knowledge as to why scientific stuff works, it is not science but magic. Once scientific or magic stuff stops happening, but you think it will happen anyway if you just keep at it, it is no longer science or magic, but religion. [Answer] First to answer your question you got to define magic, science, and Religion in relation to each other. To summarize with out going in to detail, science: is a command; magic: is a art form: Religion is a request or a negotiations. ``` science: is a command. If your using science or technology you know that if you do a certain thing your going to get a certain result. It is the most reliable of the 3, but also the least powerful. Not matter how powerful it is science is still bound by natural laws, but magic and religion are not. Magic is the middle ground between the two. Not as powerful as religion or but yet more reliable, with the opposite relation ship to science. The main different of between magic and science is magic depends on the spiritual, mental and emotional state of the magic user. If a science will work the same no mater who is doing the experiment. But I magic user doing a spell right after witnessing the death of his family may get a different result then if he had been performing the spell a week earlier. ``` This makes magic less reliable then science because the result can change if the person change, and there is no 100% guaranty that one magic user will get the same results as another. Religion: first you have to differentiate between religion and magic. Here is a simple rule, if you a spell it's magic, if a god, saint, spirit, dose a spell for you then it religion. Religion depends on your own power and/or knowledge. In Religion your not do any of work so you could use magic that you could never hope to preform on your own. Even if you have no magic power or knowledge you can still ask a god, saint, spirit or even a demon for help get a spell that only the most power magic user could preform usually. Religion is more powerful but less reliable because unlike science or magic it relies on the action of someone other then you to work. You can do all the right things and have the right spiritual and mental state, but it is meaningless unless your benefactor answers your request. And just because ( he, she, it) answers your request doesn't mean ( he, she, it) will answer in the way you want or expect. How to answer your questions : Question one:"Can I make a world that maintains this three-pillar structure without the story only making sense to readers with a strongly religious worldview?" ``` Can you tell a story about the dangers of environmental abuse that can be understood and enjoyed by people without a strongly environmental worldview?" Of course you can, as long as you make a clear to the read the difference between magic and religion and you will be fine. ``` Question 2: "All three pillars are equally important. But what does religion give?" If you need something that will work ever time every day regardless of who is using it you need science. If your in a crises that you can't solve without some deus ex machina then you need religion. If you need something between these to then you need magic. Also remember what resource a person has available to them might effect which they choose to use. A invention cost money and magic user may require money for his serves. But depending on your religion your god (or gods) may also require a price but probably something less economical and more personal. This may make the prime choice for the economic disenfranchised. What do you think of my answer. Or confused at all. comment below and let me know. So how do I reconcile all this?: I will answer this in three parts. 1 magic vs religion. The leading Religious people our subspecies of magical power that doesn't coming from ( God, or gods) since wizards and witches can do the miraculous without conforming to the religious morality there fear that this power will corrupt them. It's natural form to suppress magic and encourage divine channeling. 2. science vs religion. Scientist don't understand their religious neighbors and think that their both creepy and insane. They try their best to keep this "insanity" from spreading. magic vs science. The magic elite don't want their authority challenged by a group of peasants with modern weapons. [Answer] If all three of these things work, and they all work for different reasons, then they will all attract different types of people. **Tech** This works like it does in reality. You figure out the reproducible principles and laws of reality and utilize them in invention. This will attract logical thinkers. **Magic** This appears to work via madness. Its users are reality warpers and their power comes from them and works the way the mage thinks it works (and no mage knows or understands this point). This may attract egotistic and ambitious people. Given the inconsistent and individualistic approaches to magic used by the mages, using scientific methods to examine the magic is fruitless. **Faith** The practitioners of faith ask and an unknown force gives. When a member prays and hopes an outside force acts to aid them. The religion is based around this unknown entity. No-one really knows anything about the unknown force or has any means of testing it. Nothing happens to the person praying and they cant feel any power in themselves. If they pray for someone to be healed and they are healed, it is an unknown third party that is doing the healing. This way all three pillars work and feel very different. The kind of people who go to join each of these groups are going to have very different outlooks and perspectives. Once you localize it to your story and think through some scenarios, rifts and grievances can emerge from their interactions. [Answer] So you want all three to be valid but no one recognizes that fact and each branch tries to invalidate the other two? Maybe you can use the "we all came from the same place" trope to explain it. In the past god/gods/aliens/something else? Granted or created us with the ability to maintain an organized intelligence or "spirit" after death. But in order to maintain your spiritual self after death requires certain rituals or beliefs that allowed your mental organization to remain intact. The past society was also able to communicate with "spirits". This caused a rapid increase in scientific advancement and general increase in quality of corporeal life. Then dramatic event occurred where massive knowledge was lost, not only scientific but historical. In addition, knowledge or ability to communicate with spirits was lost. This creates a rift where people take only certain aspects of the previous society and try to make sense of the world through those limited views. Science has lost most or all of the previous advances and basically starts over and without the communication with spirits it advances slowly. Religion has snippets of how the old society was and how the god/alien/something allowed an afterlife. They also maintain some of the necessary steps for maintaining the spirit without really knowing how or why or even if they really do work. Magic has maintained some of the advanced science from the previous society that works on some of the principles of the spirit world, but the practitioners only know the way to trigger these "spells" and don't know how they fundamentally work. In this way all are valid in that they are parts of the previous whole and any conflict arises from centuries of being separated where new theories are created to explain their origins that are off the mark and invalidate the other aspects. ]
[Question] [ And could it look anything like the universe we know? *Don't get hung up on the terminology. In general, you seem to see through it easily, so I don't want any more answers mentioning that. I'll say it's a translation error: My "F" is the quantity that, in the equations of motion discovered by physicists in this universe, occupies the position most similar to that occupied by force in our universe. Things - I guess I can't call them "forces" anymore - like gravity and magnetism confer a velocity rather than an acceleration.* I ask because this way is ancient logic, "common sense", the easier way for humans to understand. But if you look more at how such a world would function, what's impossible? *I was thinking about Aristotle's "natural motion" - though don't try to be consistent with Aristotle in your answers. He believed there could be no vacuum because the only thing resisting motion was fluid resistance - that is, inertia was 0 - and any applied force to an object in vacuum would result in infinite speed. I'm taking a different approach, as explained next.* A world with no momentum. If you stop pushing a rolling object, it stops. Objects fall at a constant speed in a vacuum. *I may have meant to say "no inertia" here. What I mean is that, where in our universe inertia resists acceleration, in this universe the equivalent to inertia would resist motion.* *A recent answer required this clarification: I recognize that a universe entirely filled with highly viscous fluid would create a somewhat similar situation using physics as we know them. Objects would require force to remain in motion. However, I am not looking for that answer.* *With real physics, if you are moving and encounter a viscous medium, you will slow down, and you will feel the deceleration. In my world, you feel speed, not acceleration. Driving into a wall won't kill you, but driving too fast will. There's also the minor matter that fluid resistance is, I believe, roughly proportional to speed squared. In my universe, the (force-like quantity) required to move in a vacuum is defined as linearly proportional to speed.* Orbits are impossible. What could the astronomical-scale universe look like? Are any form of atoms even possible, or would matter have to be continuous? Are fluids possible? How might they behave? This seems to be the most critical factor in creating a recognizable world. *Assume some form of weak anthropic principle. That's the question: What other laws have to be different to create a universe that could still contain something we could recognize as intelligent life capable of drawing the conclusion (force-like-quantity)=mv?* [Answer] Answering this is tricky because $F=ma$ is just 4 symbols. We need to break it apart into its real meanings to start playing with it. $m$, for mass, isn't changing between the two worlds, so we can get away with not worrying about it here. This is good, since mass is a bugger of a concept to really nail down. $v$ and $a$ are velocity and acceleration. To haul in calculus terms, velocity is the first derivative of position, and acceleration is the second derivative of position. Because you're using $v$ in your alternate world, I'm going to assume the rules of science still apply. Now the funny thing about mathematical models like this is that variables are just letters. Force, $F$ is defined to be equal to $ma$. End of story. No can do, folks. However, the story gets a little more interesting because we **do** have something which we define to be equal to $mv$, momentum. $p=mv$ is another key equation, often considered more key than $F=ma$ because it handles objects that change mass better, like rockets. A key difference between force and momentum is that force is an interaction between two objects, and momentum is just an intrinsic trait of an object. This is where the freedom of world-building begins: how can we make a $mv$ interaction? **The cleanest path is probably derivatives.** $F=ma$ is actually the derivative of $p=mv$, if you hold $m$ constant. If we want some fictitious force, $F\_1=mv$, then it should naturally be the derivative for something momentum-like, giving us $p\_1=mx$, where x is the position vector. This has really disturbing consequences: it suggests there is truly a center of the universe, at the point where momentum approaches 0, and infinite momentum near the edges. There will be a natural tendency for the actions to have more of an effect in one direction than the other (due to the continuous change in momentum). Literally speaking, the laws of physics would be symmetric around this point. At large $x$, the changes in $x$ for day to day life become smaller, percentage wise. This means we can assume momentum of objects is proportional to mass. Literally speaking, it will be harder to make larger objects move, in any direction. At this point, you have to make a decision: do all of the forces in the universe adapt to the new interactions, or do we try to just squish things like atoms into the world? Electrostatics governs the shape of the atom. $F\_{es}=\frac{1}{4\pi\epsilon\_0}\frac{qQ}{r^2}$. If this force was simply applied to the velocity of an electron rather than its acceleration, the effect would be the immediate disintegration of the atom. **Electrons would either spring free of the atom, or be sucked into the nucleus.** One would have to write a new electrostatic force, such as one without the $r^2$, like $F\_{es}=\frac{1}{4\pi\epsilon\_0}\frac{qQ}{r}$. This would be a **completely** different system (without orbits), but it would at least balance better. We have a large number of $r^2$ based equations in our laws of motion. All of them would need to be rewritten to get anything resembling **anything** we are familiar with in this world. If you don't rewrite all of them, you can follow a simple rule: "if you can name it, in this world, it cannot exist in the new world." This is where I have to stop imagining. When there is an opportunity to rewrite every single law of matter, the degrees of freedom are limitless. You can literally create any sort of world you please once you are no longer bound by the laws we believe we are bound by in this world. Want atoms? sure. Want fluids? Sure. Want bird-sized atoms that are sentient and move about on a fluid-like body of electrons? Sure. Literally anything is open if you're rewriting the laws. [Answer] > > **tl;dr:** Such a world would be quite different from ours. Basically, all modern formulations of classical mechanics fail on it, and you also could not base that world on an underlying quantum theory. > > > I assume that you want the laws of physics as similar to ours as possible with this restraint. Especially I assume that you want to preserve an underlying quantum theory for which the macroscopic world is the classical limit. This implies that the world would be governed by a principle of extremal action (the action being essentially the phase of the quantum wave function), and therefore the classical world being described by Lagrangian equations with an appropriate Lagrangian. Since the intended law of motion does not include acceleration, the Lagrangian must be linear in the velocity, as otherwise the Lagrange equations would generate an acceleration term. So the Lagrangian must have the form $$L(\vec x,\dot{\vec x}) = \vec f(\vec x)\cdot\dot{\vec x} + g(\vec x)$$ Inserting into the Lagrangian equations $$\frac{\mathrm d}{\mathrm dt}\frac{\partial L}{\partial\dot x\_k} = \frac{\partial L}{\partial x\_k}$$ we get $$\vec\nabla f\_k(\vec x)\cdot\dot{\vec x} = \frac{\partial \vec f(\vec x)}{\partial x\_k}\cdot \vec x + \vec\nabla g(x)$$ Now the meaning of $g(x)$ is clear: It's just the negative of a "potential function" (quotes, because it is not really a potential function, just like your force is not really a force, as the units show). So let's write $g(x)=-V(x)$. WE have then $\vec F=-\vec\nabla V$ just as in conventional mechanics. For $\vec f(\vec x)$ the situation is a bit more complicated: To get the intended equation of motion, we need $$\vec\nabla f\_k(\vec x)-\frac{\partial \vec f(\vec x)}{\partial x\_k} = m\vec e\_k$$ for all $k$. However, let's write this down for the first component of $k=1$: $$\frac{\partial f\_1(\vec x)}{\partial x\_1} - \frac{\partial f\_1(\vec x)}{\partial x\_1} = m$$ Clearly for $m\ne 0$ this equation cannot be fulfilled, since the left hand side is identically $0$. In other words, your law of motion cannot be derived from an action principle, which means that your world cannot be based on quantum mechanics. Given that quantum mechanics in our world is responsible for a lot of the behaviour of materials (including the very fact that there are solid materials to begin with), this means your world must be very different from ours. Also note that all modern formulations of classical physics (Lagrange, Hamilton, Hamilton-Jacoby) ultimately depend on the stationary action principle. So basically the complete tool set of modern physics could not be applied to your world. [Answer] This is what you have in a viscous liquid. The risistence in such liquid is nearly proportional to the force exerted and in absence of foce things stop moving. There are two possibilities though. * In the absence of force things stop instantly * In the absence of force things stop gradually but for constant speed you need constant force. The later is aristotelian world and this law happens in any medium. Even in our universe at large scale: to move constntly at very high speed a body would need constant force to overcome the light pressure of CMB. [Answer] The definition of "force" is mass times acceleration, so it's not meaningful to describe what the universe would be like it it meant something else. One could, however, consider what it would mean if some quantity other than force were affected by various things much as force is. Harmonic oscillation of many kinds of objects (e.g. springs), for example relies upon the second-derivative negative feedback relationship between force and position. It doesn't matter what term one uses for the quantities that are interacting, but it's essential that negative feedback affect the second derivative. Without only first-derivative feedback, nothing can oscillate, and higher-order levels of feedback are prone to create systems which, if they oscillate at all, are apt to do so in highly chaotic fashion. Likewise, the only way planets can have any kind of orbit is if the effect of an object's position upon its gravitational effects has a second-derivative effect. If position had only first-derivative effects, then an object's trajectory would be determined entirely by its position, which would imply that gravity would always pull objects along a straight path toward or away from the center. In short, in order to define any sort of physics where F=mv work, one would have to define some means by which either an object's position could affect the derivative of force, or the integral of an object's position could affect the force upon it. Such a system would likely be like the current one, but with the word "force" used to describe momentum rather than mass times acceleration. [Answer] 1) No orbits: 1a) That means no atoms, no chemistry. 1b) That means no planets to live on. 1c) No orbits. Galaxies would collapse into a supermassive black hole. 1d) No orbits. Galactic clusters would collapse into a supermassive black hole. 2) Temperature is motion. Motion dies away--everything very quickly cools to absolute zero. 3) Everything at absolute zero means ordinary stars can't exist. Fusion could still occur once the pressure gets high enough. That means degenerate matter (if electron degeneracy means anything in a world without orbits) and the normal thermal regulation doesn't work. You would have dark bodies that simply sat there until they reached 1.41 solar masses and then detonate in a bang that would outshine a supernova. However, the mass thrown off by the detonation would soon stop and then fall back due to gravity. The light of the supernova would fall off **much** faster than normal and the star would soon reform, albeit slightly lighter. It would detonate again when enough material had fallen on it, each subsequent detonation would be a lot weaker than the previous ones as the material went up the periodic table. They would eventually cease when the star had been replaced with a great iron ball. Note that no mass escapes, the interstellar medium remains as it did after the big bang. Planets can't exist because there's nothing to make them out of. [Answer] (Force) (is proportional to) (speed difference) is a formula that describes "dynamic friction". It is a significant part of many real-world physics (aka engineering) problems. Natural and artificial bearings (including hips) are designed based on this force. (Force) (is proportional to) (fluid density) \* (area) \* (speed) \* (speed) is a formula that describes "air resistance". It is a major part of many engineering designs, including the shapes of animals, plants, cars, and planes. [Answer] This obviously throws all of physics out of the window. For starters, as @Russell points out, the velocity has to be relative to something. There therefore has to be a fixed notion of position, and being static. This overthrows one of the fundamental assumptions of the Theory of Relativity, and so the Big Bang is out of the question. You're going to have to think of another way to get any sort of astronomical scale universe. [Answer] Basically, you're proposing a universe in which constant forces are required to maintain constant velocity, instead of to change it as our own universe allows. In addition, an increase in force is an instantaneous increase in velocity, or infinite acceleration. In such a universe, the energy required to exert force would be depleted almost instantly, and F=ma=mv=0. [Answer] In this case it is best to replace the terms with new terms so that we can use different units. We could use the terms SRF for second rate force, srm for second rate mass, srp for second rate momentum, and SRE for second rate energy. For force we have the equation F=p/t so for second rate force we have the equation SRF=srp/t and if we use the equation and so if we use the equation SRF=(srm)\*v for the second rate force then that means we need to use srp=(srm)\*x for the second rate momentum. Just as momentum in our universe is direction dependent the second rate momentum in your universe would also be direction dependent. For the second rate kinetic energy we can use the equation SRKE=(srm)\*x^2 so that the second rate kinetic energy does not depend on direction. This would mean that the units for the second rate mass would be srkg for second rate kilograms, and the units of second rate momentum would be (srkg)\*m, the units for second rate force would be (srkg)\*m/s, and the units for second rate energy would be (srkg)\*m^2. In the universe you are describing the second rate momentum and the second rate energy would be conserved as that way objects would be unable to move without interacting with each other as that would violate conservation of second rate energy, and second rate momentum. This would also ensure that two objects that are applying second rate forces to each other will experience equal and opposite second rate forces. In this case there would not be relativity in terms of speeds as anything that would be moving would experience a second rate force meaning it would be possible to tell which objects would be moving and which are standing still. There would however be relativity in terms of position values however as physics would not depend on an objects position value and so if there were two object it would not be possible to tell which object is at position zero and which has a none zero position. This would also mean that the second rate momentum and second rate energy of an object would depend on the position reference frame that their second rate energy and second rate momentum is being measured from. In our universe in addition to force being a type of interaction there is another type of interaction known as elastic collision in which the energy before and after the collision is the same. In this case we might imagine that in the universe you describe there would be an interaction known as second rate inelastic collisions in which the second rate kinetic energy would be the same before and after the collision meaning that there would be no conversion of second rate kinetic energy into second rate potential energy. If we assume that second rate elastic collisions work by first converting second rate kinetic energy into second rate potential energy and then back to second rate potential energy then the second rate elastic collisions could produce harmonic motion as two objects keep having elastic collisions with each other repeatedly. This also means that stable structures could form that would be held together by the equivalent of elastic collisions instead of by the equivalent of forces. Objects that are made of particles that experience constant second rate elastic collisions would behave like a cross between a liquid and a solid as they would not flow and would tend to retain their shape but particles could move through them freely through the equivalent of elastic collisions. This is the reverse of our universe as in our universe if something only has elastic collisions in it then it will disperse over time while attractive forces can cause stability. In the universe you describe any unbalanced force would prevent the universe from being stable but the equivalent of elastic collisions would lead to stable motion and potentially complex structures. [Answer] ### Changing the formula doesn't change the world. The easiest, and most obvious answer to your question is: "Yes, of course". Just switch the meaning of 'v' and 'a'. So in your world, the word 'velocity' has been replaced by 'arrow-speed' and the word 'acceleration' has been replaced by 'voom-crease'. So the great Physicist 'Oldton' derived F=mv. It's important to get that there are (at least) two schools of mathematics - Platonists, and Formalists. Platonists believe that formula actually correspond to the universe somehow. A few physicists are Platonists. Formalists see formula as expressions that can be juggled according to a set of rules. In Physics, almost every physicist accept that the formula we have for describing the world that we measure models, simulations, representations. If we didn't accept that, we would have to start looking for ideal objects in nature, and we don't find them. So, another way of looking at this is regarding the progress of science. Pre-Newtonian physics used all sorts of different answers, such as the theory of impetus. Post Newtonian physics replaces f=ma with [![relativistic version of f=ma](https://i.stack.imgur.com/84qfA.png)](https://i.stack.imgur.com/84qfA.png) ]
[Question] [ Could a civilization grow or develop to advanced levels if they don't hold religious beliefs? I have just watched Star Trek: The Next Generation, "[Who watch the watchers](https://en.wikipedia.org/wiki/Who_Watches_the_Watchers)" (season 3, episode 4). It tells the story of the Mintakan people, a proto-Vulcan race near a Bronze Age of cultural development. It is clearly said at some point, that millennia ago members of this civilization has dropped believing in any kind of gods, supernatural beings or any other kind of faith-based mythology. And yet, they're still remains in a Bronze Age. Is this possible and believable? We're far more developed than Mintakans and yet we have many gods, supernatural beings and other faith-based believing. As we look through our history, even (or especially) this after Bronze Age, we can clearly see many examples that this believes were actually a stimulating factor to many discoveries, achievements etc. From Christopher Columbus, who found America mostly to prove, that Church was wrong. To Stephen Hawking, whos many works were meant to prove that everything is explainable without the need of God existing, led to many new discoveries in physics. But, these are only two of large number of examples, that searching to disobey some believing, to disprove existence of some gods or other religious of faith-based myths, was one of fundamental elements of our civilization development. As you can see from above, I'm personally believing, that thesis shown in mentioned Star Trek episode is unreliable and impossible. In my opinion, it is impossible to advance any civilization to our level of development or further, when denying all believing, faith and religions. I'd like to challenge this in worldbuilding terms. Is it possible to have modern, advanced civilization without faith? If yes, would that kind of civilization need some replacement for faith and religion to stimulate its development, and what kind of replacement would that be? [Answer] I think this is a question too subjective to have a correct answer. In consequence, my answer (and I believe all answers) will also be quite subjective. I don't agree with you in that a civilization cannot develop without religion. In fact, I personally believe that the lack of religions would solve lots of problems of a civilization, and would make its development faster, because it would prevent, for example, most wars. I can't think on some advancement impossible without religion. Even the examples you are proposing aren't impossible at all, and would have finally happened, although maybe later. However, even if a civilization could develop without religion, I think **all civilizations do depend on religion/magic on an early stage**. The human being constantly tries to explain its environment. On an early stage of development, there is not another explanation than religion/magic. This is why most prehistoric civilizations are known to worship the sun or the earth. When those civilizations evolve (for example, on an stage of development similar of that of Ancient Greece), the need of something explaining the world remains, but the religion is less primitive. The birth of science led to the first atheists, but that science is far too incomplete to explain the world. Finally, on our stage of development, the completeness of science is which makes a part of the population atheist. This percentage is likely to continue growing with the further development of science. In conclusion, development is possible without religion, but it will never happen because humans will create something to explain their world. Finally, to end with an example, as far as I know all of the underdeveloped human tribes which are still on a "prehistoric cultural stage" believe in some type of God/myth which explains the world. [Answer] I believe it is possible. Consider many early religions, they were based around trying to explain the world as the civilisations saw it. The ancient Egyptians believed there was a god called [Ra](http://en.wikipedia.org/wiki/Ra) who carried the sun across the sky, Norse civilisations belived [Thor](http://en.wikipedia.org/wiki/Thor) was responsible for the terrifying thunder and lightening they saw. These deities were an early attempt to explain concepts far beyond their understanding. We now have a different theory (based on a lot more evidence) for why the sun moves across the sky or what causes lightening. My point is that in many cases these deities were early attempts at understanding science, people looked around them and saw people. They saw the sun move, therefore it was a sensible suggestion to suggest that someone was moving it. However, another explanation may have been the sun is ballshaped therefore it's rolling across the sky. Or that lightening often occurs at night - perhaps its bits of left over sun escaping? If a civilisation was to create other reasons to explain the (to them) magical world which didn't involve more powerful beings the a religion could be formed on science. There is also the counter argument that the church has held science back, there is evidence in our world of medical advanced being prohibited up until the renaissance periods. It is entirely possible that not having a religion based society would allow science to advance quicker. In my opinion however that's short sighted, the fact that religion has attempted to hamper science in the past is coincidental. In your world a dominant ruler, a highly respected scientist could just as easily hamper new and original theories. **TLDR** Yes it is possible, many deities were created to explain things earlier civilisations didn't understand. If these people formed conclusions free of the concept of powerful beings then their ideas may have evolved very differently. [Answer] I too believe that religion and science don't always go well together. It depends how people link these two. The Greeks believed in the gods but also they also made science make huge progress. In the middle ages, things started to change in Europe but not in the Muslim world. Muslims were really devoted to their religion and science really improved during the Abbasid (for example). Christians believed that the work of God was superior to mankind and therefore it made scientific researches clash with the religious doctrines. I'm not saying that there was not technological progress in the middle ages but the religious beliefs made it harder. But this did not last forever. Customs evolved and reason supplanted the religious way to explain how things work. People still believed in gods (and many still believe today) but they now know that reason is usually better than religions to understand the world. Today, we continue to make progress without the religions but we could ask ourselves where we would be if religions had not existed. If it's possible to have a pre-industrial world without any kind of religion. (Confucianism is really important in China but it has no god. I consider this as a belief rather than a religion even if they more or less serve the same purpose. But it coexisted with other religions like Buddhism.) If people don't believe in gods, they have to believe in something. Humans can believe in science and they can believe in themselves. Some even said that Marxism, feminism, and other things ending in ism could be substitutes to religions. It,s also possible to believe in nothing I guess but I'M getting out of topic. Well, it does bring the point of what you mean by belief. [Answer] Well if any of the many religions here on Earth are true, then there won't be much "advancement" without acknowledging the truth and basing your understanding of reality on it. It also depends on how you define "advance" or "better" with regard to human society and behavior. I'd say so-called uneducated people who unconditionally follow the Golden Rule are far more advanced and better than so-called educated people who don't, but not everyone would agree with that. You ask "is it possible to have a modern, advanced civilization without faith?" While theoretically possible, since there has never been one that existed outside the fantasies of the mind, and there have been well over 100 recorded distinct civilizations, the reasonable answer in my opinion is no. After all, it is <%1 probability historically. [Answer] The main issue with answers so far is that they all talk about how human civilizations develop. But the question does not ask only for human civilizations, which we know how the only one has developed, but for civilizations at large. Can a civilization develop without religion? Of course yes. Human dependence on religions on early stages is caused by our need for explanations about "How the World works", the eternal "Why?" question. (The answer, anyway, is 42). But a species without that need for knowing the Why, but with an ability to learn and keep knowledge, is perfectly able to develop (slowly, since there is no curiosity) without any kind of religion. They simply do not need it. [Answer] Faith in general does not provide you with anything physical, so aside from cultural issues, it is very possible that a society can exist without faith. Bronze, copper and whatever else is necessary is not found through believe, and methods of utilizing it are not given to men by gods or similar, it is simply curiosity and drive that causes a society to advance technologically. How the culture exists on a social level however is a different question. Faith and associated religions have often been used to keep the common people under control, give them a reason to exist or to endure difficulties, and sometimes even inspired them to archive things others would had considered to be impossible. Without faith a culture would have to understand their existence well enough to no longer need any form of believe, and to maintain order on their own. Otherwise they would fall into chaos, which not necessarily destroys a culture, but might turn them into a very evil and self-centric one. The Vulcans are a special case here, as they suppress all emotions, and suddenly many things no longer require faith, as they can be explained through logic. The need to faith is replaced by understanding and logical conclusion, so the culture was able to strife without any believe system. [Answer] I would say that civilization requires faith at least in beginning and probably always. Evolutionary game theory strongly suggest it does. As products of evolution by natural selection, we are innately selfish. Our behavior is anchored in hardwired desires which in turn focuses on short-term survival and reproduction. Even our reason ultimate depends on hardwired emotions. We can't use reason to decide between two courses of actions unless we first desire one outcome over the other. When tend to rationalize why we should fulfill our desires, to the harm of others, much more often than we rationalize we should suffer loss or take risk for others not genetically related to us. If one looks at religions form the perspective of behavior control, of suppressing short term immediate selfish impulses to foster long term thinking and cooperation, then all religion look the same. Religions impose significant material cost on societies, especially in the materially poor past. There is an odd concept that our forbearers were morons stumbling around in a superstitious haze bumping into trees. But our forbearers had far fewer resources than we and far less margin for error. Their ***behaviors*** had to be more precisely adapted to circumstances than ours. When the population devotes 90% of it's efforts just to grow food, there's not a lot of room for maladaptive behaviors. We've fallen into the trap of thinking them foolish because we regard their ***explanations*** for why they made this or that choice as nonsense. What we missed was that the explanations are irrelevant, only the consequences of the behaviors matter. E.g. many traditional medicines work even though the explanations for their mechanism of action are nonsense. There is no connection between a justification for a behavior and the adaptive benefit of the behavior. It does not matter why someone believes that should act less selfishly, it only matters that they do. If religions did not produce some concrete material good, very quickly selection forces would favor societies with progressively less and less religion. Societies that wasted resources on religious constructions, manpower on clerics and time on rituals would be outcompeted by societies who could use the same resources for roads or defenses, the same manpower for work or war and the same time for production. Instead, we see religion being completely ubiquitous throughout history and the most dynamic and innovative cultural periods also being ones of great religious fervor. The problem that religion fixes is that morality is something of a lie when looked at from purely materialistic terms. If an individual can get a signficant advantage by harming another without paying material consequence, then evolutionarily, there is no reason not to. That is especially true in primitive conditions where material consequences are unlikely and interdependence low. With the experience of thousands of years of practical experience behind us, we can argue that enlightened self-interest might guide us today, but how did the ball start rolling in the first place? How do people learn to cooperate on progressively larger scales when everyone can determine rationally and accurately that they personally could benefit from quicker and surer by cheating, exploiting and killing? That's were religion comes in. It invents a consequence where one does not not exist. Religion supplies the one behavior modifier that no secular idea can: inescapable consequence for moral choices. For the faithful, regardless of the faith, their is always an inescapable consequences for selfish moral decisions. In a purely secular society, the most power humans, or one thinking himself just smarter than those around him, have no rational incentive not to abuse others. In a faithful society, however, the behavior of the most power human is still subject to to judgement by the divine. Whether that conceived of as a personified god or some mindless supernatural force doesn't matter, nor does it matter if it "true" to any degree. To produce a positive material effect. It just matters that most believe inescapable consequence will fall upon the selfish and uncooperative. Once the belief in such inescapable consequence becomes part an axiom for one's reasoning, then cooperation, self-denial and self-sacrfice appear rational and optimal choices for individuals. More over, if one knows that most of the rest of a society believe the same thing, then it is rational to assume their behavior is likewise moderated making them more trusty. This lowers transaction cost and increases social cohesion, making the society materially wealthier, less internally contentious and more militarily effective. All the great periods of dynamic innovation and growth in human cultures are associated with ages of great piety. On the other hand, the direct example of the last 200 years strongly suggest that polities grow more brittle and prone to violence as they grow more secular. Since the French Revolution onward, the more secular the dominate political ideology, the more murderous the regime. Robespierre feared no divine consequence and neither did Lenin, Stalin, Hitler, Mao, Kim il Sung or Pol Pot. Once they reasoned that their actions were necessary and that they could escape material consequences for their choices, there were no limiters on their behaviors. Since we are trapped with our darwinian cores we may always require that a high percentage of our population be religious. It's pretty clear that we really needed it in the past. [Answer] Faith is belief in the absence of evidence. Strong faith is unshakeable belief in the face of evidence to the contrary. Neither of these is conducive to an evolving understanding of reality. --- You have conflated correlation with causation. Religious belief *retards* science and technology because why look for answers when you already have them. Undoubtedly you will now object citing monastic centres of learning and various inventions that came out of them. To this I answer that progress during the Dark Ages was very slow precisely because control was in the hands of the church. Technological development is hostage to surplus. There are three things that will stymy it: 1. Slavery - what do you need a machine for when you can make someone else do it? In a slaving society, technology is pointless and expensive. Developing even more so. Philosophy has all the intellectual posing advantages and it's cheaper. 2. Religion - all the answers come from the priesthood. Looking elsewhere is suspicious and *finding* other answers gets you branded heretic. Even if the church is well pleased with your new idea they will dispose of you anyway and have a divine revelation. 3. Relative scarcity. The renaissance occurred as a direct and immediate consequence of the Black Death's rapid depopulation of Europe, which left all the assets intact. For the first time, trade skills were so valuable the balance of power shift to craftsmen. Even the value of peasants rose; it was hard to get enough staff to farm your land. The dire need to get higher yields at every level of civilisation greatly increased the value of reach-extending technology like better ploughs, water-mills, wind-mills, weaving looms, then mechanical looms, then power mechanical loom... *This* is why nothing happened for so long then steel to silicon in ninety years. And none of this happens when people think they already have all the answers in a book about the creation of the world by their psychopathic invisible friend who occasionally tells them to kill their firstborn just to see whether they're stupid enough to do it. Once the Black Death gave men respite from scarcity and the renaissance began, it was in the minds of men that the church didn't have *all* the answers. Fortunately it also gave men respite from oppression by the church. God's protection wasn't much chop and the power of the church was also broken. Otherwise it would have enthusiastically put a not-very-merciful stop to independent thought of any sort. [Answer] I would suggest that the universe is too populated for there to be a planet without the dichotomy of those-with-advanced-knowledge and those without. No matter where you go, there's going to be visiting aliens who seem like gods to the inhabitants. And then, this existence will continue for the planet dwellers until such a time that they've intellectually grown up. They realize that they've had neighbors all the time and that their advanced physics really isn't magic or supernatural after all. At this time then religion converts into appreciation or awe or envy or even fear. [Answer] Science is predicated on philosophical naturalism. It's not faith-based, or atheistic, but it is largely agnostic, or more accurately theologically noncognitivist in how it formulates and tests answers. It doesn't matter if there's a god, or if god was responsible for an apple falling, because that doesn't tell you anything about the nature that god created in which apples fell. Many Christians were humanists and naturalists. They believed that God set the rules, but that the rules themselves were knowable, measurable and predictable - and what's more, they saw this measurable predictability as evidence of God. Some theologians took issue with naturalism, under the belief that it removed God's imminence in all things. But both interpretations were possible within the religious constraints of the time. I believe that religion is man-made. And as such it's simply a context in which human beings discuss and analyze things. It's not magical. It's self-serving. If scientific discovery serves individuals well, then religious people will encourage scientific discovery up until the point that it threatens their comfort or power. The Church didn't mind using Galileo's heliocentric model of the solar system to keep track of religious holidays, so long as it remained hypothetical. So yes, civilizations can develop with or without faith. Civilization cannot flourish without at least a modicum of free thought. Religious beliefs typically slow the rate of change, or set it back for a few centuries, nothing more. You don't need religion to formulate dogma or create taboos. Religion is what people label their personal preferences, where they store their anecdotal wisdom. Unless you have a religion that successfully stifles technology and information transfer, which we saw in the dark ages, but eventually mankind got back in the game (or Europeans I should say, I think the Eastern world was trucking along okay during that time). [Answer] I think religion is inevitable for a species like ours, because it ties into how we handle **[risk assessment](https://www.psychologytoday.com/blog/the-inertia-trap/201303/why-are-people-bad-evaluating-risks)**. The key is that at points during our evolution, we lived in very small groups. This made it beneficial, from an [evolutionary standpoint](http://www.nature.com/articles/srep08242), for us to treat risks oddly. An irrationally cautious proto-human was more likely to survive and breed than a rationally risky one. So we're literally programmed to be bad at math in critical key areas. You can see this in how we handle things like [lotteries](https://en.wikipedia.org/wiki/Apophenia) or safety in sky diving ([risk homeostasis](http://www.dropzone.com/safety/General_Safety/Risk_Homeostasis_and_Skydiving_663.html)). This fundamental evolutionary irrationality ends up manifesting as religion, because a large percentage of humans will see patterns that aren't there. This gets treated as spiritual events, miracles, etc. Eventually, [confirmation bias](https://en.wikipedia.org/wiki/Confirmation_bias) locks it in and you end up with long-term religions that reject outside rational explanations. So, I would say that it is very likely that any species that evolved in small groups will develop religion, because at some point being hunted will create this type of beneficial irrational behavior. However, you might see a non-religious swarm species. Say if ants or bees eventually became intelligent - they can afford to be rational because they have the numbers to play the odds correctly. [Answer] There is a pitfall of bias by many. The roles of faith: * Explain what is not known * **Moral code and value system** * **Unifies the people** Religious figures like priests create primitive governments that are ruled by the law of god. The belief of good and wrong create a system where people will not abide the laws only by the fear of law enforcement. Before modern era the law enforcement did not have the same global reach. Communities are built around worshiping gods. How I see it, the religion provides a strong power that can unify huge groups. Without Vatican and crusades, the Europe would have been overrun by the caliphates => Europe would anyway have a religion, although a different one. [Answer] the fact is we have in Brazil a almost atheist indigenous people, so there is no strong law enforcing religion for primitive societies: [Pirahã people](http://en.wikipedia.org/wiki/Pirah%C3%A3_people) note they are in stone age, not bronze age. But the religion plays a role in the development of civilization. Without religion would be necessary another form of central ideological power, and maybe these is mandatory. Also, religions can vary a lot. Sumerians don't believed in [afterlife](http://history-world.org/sumeria,%20death.htm), a essential component in nowadays religions. Romans have many lares, deities without form or appearance. [Answer] I think something important may have been overlooked in the premise of the question... Faith is, or at least can be, a much broader term. Religious or supernatural faith, belief in unseen powers at work in the universe, is but a tiny sliver of the faith that most people demonstrate. People have faith in themselves, in each other, in leaders, in institutions, in governments, in philosophies, and even in science. The list could go on indefinitely... Is a soldiers faith in his commander or country all that different from a priest's faith in his god? Do these belief structures not provide many of the same sorts of rituals, symbols, morality, codes of conduct, and so on? This may seem to be generalizing an awful lot, but everyone seems to have faith in something, even the atheist has faith in his/her own reasoning. So... Could a society develop without faith? Probably not. Could a society develop without supernatural faith? Most likely yes. [Answer] It depends a great deal on how you define "faith". Human civilization has often tied together the concepts of 'explaining the natural world', 'explaining the birth of nations', and 'encouraging people to follow the rules of society', which we tend to lump under the broad concept of gods and the supernatural. While the first aspect could be largely done away with in a society that somehow attained advanced science early, and the second aspect can be done away with if a nation recorded its history accurately from the very beginning, the third aspect is very difficult to pull off without either 1. belief in some kind of moral code that exalts people who live according to its laws and encourages people to look down upon those who do not, or 2. an authoritarian rule, often operating under a totalitarian dictator who effectively functions as a god incarnate, at least in the eyes of the people. Atheistic societies can exist only if they substitute 'gods' with a suspiciously similar substitute that encourages society-promoting behavior, which generally relies upon faith that *the system will work* and people who "follow the rules" will be "rewarded" for their behavior in the end. Without this, society will devolve into anarchy. Most humans are not altruistic enough to reliably make sacrifices without the belief that they will get something in return. (A society built by a naturally altruistic eusocial species, such as intelligent ants or bees, may be different.) While anarchistic societies based on merit and natural social encouragement/discouragement can and have existed (the first human societies were like this), they are by nature small - no bigger than the average "social circle" - since every person must be aware of every other person in the society to ensure people are contributing and reward/punish behavior appropriately. A major civilization could not develop in this state. [Answer] I find it interesting that your own argument supports the Star Trek episode. You said you find it to have been impossible for us to have developed modern civilization without religion pushing the changes (mostly be others trying to prove them wrong). The civilization you are talking about has only made to the Bronze age and seems to be stuck there? However, most religions and beliefs are based on our fears of the unknown and wanting to feel someone/thing can control the fickle fates of life (one we can appeal to in our favor). If for some reason a people are fatalistic or just unafraid of say dying, they would have little reason to believe in anything supernatural. ]
[Question] [ This is a question I've been wondering about for a while. If I wanted to give my characters the best possible chance of surviving my story's Armageddon, what time of year should I schedule it for? Let's keep the scenario as general as possible for maximum usefulness to people who aren't me, while still laying down some ground rules. Let's assume some sort of global EMP attack / solar flare that destroys the entire world's electronic infrastructure. No radiation, no explosions, no immediate deaths. But everyone's left without electricity, running water, sewage, and every other part of the vast network of societal services we perpetually take for granted that keep us from having to fight every day for the right to breathe. What's left of the government is rapidly breaking down, the stores aren't restocking, and people have to secure access to food, water and medicine, acquire the means to defend themselves from others, etc. Let's further narrow it down to focus on the USA, since I know that the seasons are wildly different depending on where in the world you are, and lots of other factors could be in play to make the answer a great big "it depends". **What time of year should I have this event take place in to make sure that the greatest number of people has the greatest chance of living to see next year?** [Answer] ## Mid Spring Around late April the last freezes will have passed through the U.S.. It will be possible to remain outdoors with little protection for seven months from this time. Farmers will have already prepared their fields (which would have required the heavy equipment) and planted the first crops of the year. Setting up manual irrigation will not be an unbearable challenge. Soy is ready for harvest in a month. There will be time for multiple plantings and harvestings of this staple calorie crop in rural areas, and also plenty of time for urban areas to establish farming in any areas suited for it. There will be plenty of time to build new things. Most sewage systems are based on gravity allowing everything to flow down hill. With a little work, people may be able to get sewage and water working in places where there is easy access to springs, rivers, or mountain runoff. There's also plenty of time to prepare for a winter without heating. Time to chop wood, knit blankets, buy extra clothes, can food, make candles for the long periods of darkness. [Answer] # December 31 It can be trivially demonstrated that if the Armageddon happens on December 31 the greatest number of people will have the greatest chance of living to see next year (actually, pretty much all of them will!). . PS: In case you also wanted to include people in different timezones all around the world, you may wish to expand that a little up to 23:59 of 30th December. [Answer] # September Summer is a busy time when people are unsettled and often off traveling. Kids may be separated from their parents. A lot of people move in the summer. But once school starts, people are pretty settled in for the year. Even people who aren't in school or parents of children in school (or working in schools) tend to move with that schedule. In cold weather areas, crops are mostly in by September. In warmer parts of the US, a lot of crops ripen year-round or specifically in the fall months, but food and survival temps aren't as critical in winter. Because of "back to school" and the end of the travel season, stores are well stocked with goods of all kinds. Summer heat is more or less over (sometimes you get a last hurrah) so super quick food spoilage, issues with sewage, trash, and corpses (the event may not have caused deaths but people die anyway), and the death of fragile people from not having air conditioning are not strong concerns. It may be cold at night, depending on the location, but it's a few months before the worst of winter and accumulation of snow. This gives people some time to prepare. September is a great time to can food (and there should be enough fuel left to do it) and semi-perishable foods can survive outdoors, at least overnight. It's a good time to cut wood and prep fireplaces (for those lucky enough to have them) for use. Some may be able to buy wood stoves (there are some designed to use existing chimneys) which are far more efficient than fireplaces and allow cooking too. Some families will move in with each other to conserve fuel and other resources. For local communities that choose to work together under effective leadership, everyone should survive the winter (aside from some with severe medical conditions). If people don't panic and if government stays intact, a lot of places will be able to function. Small rural towns are the best bet as they're likely to have horses or oxen available, may grow their own food already, have wood for heat, and don't have too many people to fight over resources like generators and fuel for cars and trucks and tractors. Cities will be in trouble because most food must be trucked in and cities have more complex infrastructure. And potable water...big problem. Their survival will depend on a lot of things but having the event occur at the very end of summer is their best chance. [Answer] **Christmas** (seriously) *NB: there appear to be some MASSIVE misconceptions going around as to what I'm actually saying here, so I'm going to clarify as part of this edit inside the various sections. But first, some theory.* *Surviving ANY end of world event, whether it be the end of power generation or the zombie apocalypse comes down to one factor - preparation. If you're not prepared for the end of the world, you're highly unlikely to survive, but the longer you survive, the better your chances of remaining alive. Remember Y2k? We all had our pantries stocked, fuel in the car, just in case. Same deal here.* *Also, I'm not suggesting that this is a* great *time to survive; not at all. Most people are still going to die. What I AM saying is that because people are already planning to have family around them for an extended period, and have stocked up on food, blankets et al accordingly, they have a better chance of survival than they otherwise would, but in many cases this is still not going to be enough. But, on with the answer...* If we narrow it down to North America in particular, there are several advantages to this being your chosen date. **1) Family** Christmas is often seen as a time of family, so small family gatherings are happening all over. This is actually a good thing, because less people are going to be out trying to find loved ones, and those you care about are already grouped together in a small 'clan' that is determined to look after each other. **2) Food** These aforementioned families have already stocked up for the Christmas period and therefore have an advantage in terms of managing food supplies going forward in the initial chaos while they work out what to do next to sustain themselves. **To address comments;** I'm not suggesting this is a long term fix, merely that this will give you enough time to plan your next move. The fact that you've planned for a feast means that you can ration it out for a bit and figure out how to get to a ready food supply from there. If you have this, you have a small buffer. If the end of the world occurs without this buffer, then the very next morning you're raiding the local supermarket like everyone else. That lowers your chances of survival, especially if people start bringing guns to this particular party. **3) Cold** Sure, not nice to be out in, but if the power goes out, all that aforementioned food hoarded by the aforementioned families will go off at a slower rate. Still not good if you're in (say) California, but in Illinois or New York, you could almost freeze your food by leaving it outside. **To address comments;** I'm not suggesting here that this will freeze food, and in point of fact that would be counter productive. What I'm saying is that if you somehow find a way to get your homes warm, you don't want your food in there because your fridge won't work. Put your food in an eski (or cooler for our US friends), out on the snow, to keep it cold, not frozen. You still want ready access to that food in the short term. **4) Traffic** Because the families are already together, there's little need to travel meaning that the roads are freer for the emergency services, assuming of course they can get their cars and trucks working. That means that as issues arise, the emergency teams can respond more rapidly than they could if everyone was trying to get to family or just plain get out of dodge in a disorderly fashion. ***The Caveats*** This is still a catastrophic scenario by most standards. Large population centres (cities) consume a lot of food, and produce almost none. Many of the people in these population centres start dying after a few days no matter what you do and civil disturbance will be on an exponential curve when the food starts running out. Add to that the fact that the cold is a two edged sword insofar as our warm-blooded metabolisms mean that we need to eat *more* during the cold than otherwise, so that food that lasts longer before spoiling gets eaten faster to avoid starvation. Also, EMPs and other technology neutralising phenomena will make it much harder to coordinate responses and the like, and most of the people who survive from the cities will do so by walking out of them immediately. Some of those families (for the reasons mentioned above) will be less likely to do that at Christmas. The real winners out of a doomsday scenario at Christmas in North America are going to be the small communities across the food belt of the USA, where they have family around them, a supply of food and the capacity to grow more as they go, not to mention having herds of cows and sheep to survive off while crops regrow. **To address comments;** I can't speak for Iowa as I've never been there, but ultimately when we talk about the *theory* of survival, it comes down to this. In the short term, having family and friends close and ready to work together as a team, as well as reserves of essentials like food and blankets, increases the **chances** of your survival, but doesn't guarantee it. In the long term, being where you can grow and store food increases your **chances** of survival, doesn't guarantee it. Just like being caught outside without heating in the snow belt is going to massively increase the risk of you freezing, being in the Arizona Desert with no air conditioning, food or water is also going to decrease your odds of survival. Ultimately, you want a place where it can be temperate most of the year and have a steady supply of food, for **long term** survival. But, you don't need to worry about long term survival if you can't survive in the short term. So, being prepared by having your family close and a stock of food is your best bet. That sounds like Christmas, to me at least. [Answer] You can write off 999 people out of every 1000 no matter what time of year it is. Any disruption to the food supply will doom the people whose every bite of food up until this point was bought in a store or restaurant. There will be immediate looting of every place near a city where food is stored or sold, and only a fool will try to re-stock them. Our major cities will dissolve into gang warfare over the dwindling supplies of food (and over racial/ethnic/religious hostilities where those were already present). Some of these gangs will spread out along the roadways leading from these cities, so the turmoil will eventually reach smaller cities as well. The survivors will be those people who move as quickly away from civilization as possible. Of these, only those who can live off of the land, or learn to do so *right {filtered} now*, will be alive six months later. The best time of year is whenever the people who flee the cities, but who cannot live off of the land, die quickly enough that they don't interfere with the people who *can* live off of the land. My apologies if that's a wee bit grim. --- **Addendum** For a picture of what it will be like, read any historical account of a siege, paying particular attention to what happens when the food runs out. ]
[Question] [ This is specifically about the climate, and where on the planet it would be mildest. Imagine Earth, rotating at the usual distance from the sun. Except, it is tidally locked to the sun; a so-called **"Eyeball Planet"**. One spot on the earth is always directly facing the sun; lets call this the **"Day Pole"**. Opposite that spot would be the **"Night Pole"**, eternally dark and impossibly cold. To my understanding the Day- and Night-Poles' extreme climate would make them entirely uninhabitable, unless I'm mistaken. What we will call the **"Equator"** on this earth is the band exactly between these two poles. At any point somewhere near the "Equator" the light would be like different levels of permanent twilight/dusk. **My question is, Where on the planet would the climate be most hospitable for earth-life, in relation to the Poles and "Equator", and where in the sky would the sun be if you were there?** [Answer] # The sunlight equator, sort of First off, let be sure to distinguish between the sunlight equator that you are talking about, and the planetary equator that we have on our planet. The Earth is already at a distance that supports an optimum *average* temperature for life (~14 C). Therefore, if you keep the Earth the same distance from the sun, but make it tidally locked, you will end up with a hotter day pole, and a cooler night pole. However, another thing to consider is that the angle of the sun's rays is still pretty large at the northern and southern latitudes. Therefore, those regions will not receive as much solar radiation per surface area as the planetary equator. The last thing to consider is that there is still a Coriolis effect of sorts. The rotation of the Earth matches its rotation around the sun. This will cause warm air rising from the day pole to move from west to east, thereby making the areas to the west of the day pole warmer than the east. Put this all together, and your optimal temperature regions will be roughly in a gradient from the day pole to the sunlight equator, with the gradient shallower along the planetary equator and the in the westward direction. See [this answer](https://worldbuilding.stackexchange.com/questions/4850/how-would-winds-behave-on-a-tidally-locked-planet) here regarding winds on a tidally locked world for more information. Regarding the sun's location in the sky, it would be up to 60 degrees off the horizon to the north and south of the day pole, and as low as on the horizon, along the planetary equator to the west of the day pole. In all cases, the sun would be in the direction of the day pole. Side note, at ground level you would expect a cold breeze from the night side to be blowing towards the day pole, since the warm air escapes the day pole at high altitude. So everywhere is going to have a chilly breeze. [Answer] The name of what you and the first answer call "the (sunlight) Equator" is actually the **terminator**. The [terminator](https://en.wikipedia.org/wiki/Terminator_(solar)) is the line that separates the day and night sides of any astronomical body. On an airless place like the Moon the terminator is clear-cut, while on a body with an atmosphere, like Earth, it's fuzzy. Even on a tidally-locked planet the terminator would not be an unmoving line, since unless the orbit is almost exactly circular the terminator will oscillate as the planet moves. This is called [libration](https://en.wikipedia.org/wiki/Libration). Earth's orbit is not very eccentric but it is not circular, so as the planet moves in its orbit it sometimes goes faster (near perihelion) and sometimes slower (near aphelion). The speed of Earth's rotation around its axis, however, does not change, so the terminator will sometimes get ahead and sometimes lag behind its supposed, average "fixed" position. The libration zone will be a thin ring around the great circle that separates night and day; inside that zone the sun will appear, go up a bit, then stop and then go back down. This area, I think, would be a very interesting place to inhabit. It will never be too hot or too cold and it will experience some of that alternation between light and darkness that is essential to many biological creatures. It will also have an interesting weather. It should in fact have something like (very mild) seasons. Since this is an alternate Earth, you could maybe choose to make its orbit more eccentric and thus make the libration zone broader. [Answer] Life would exist everywhere on the planet. We currently find life in boiling geysers, in volcanic vents and at the South Pole. High-flying test aircraft have captured mold spores in the stratosphere. Everywhere we look on Earth there is life. If Earth was tidally locked to the sun, the side facing the sun would have a constant updraft. The pole facing away would have a constant downdraft. In between would be a stable, continuous planetary cyclone. This would have a cooling effect on the sunny side and a warming effect on the winter side, though the extremes would be "extreme." This constant airflow would provide a means for life adapted to the dark side to exploit the nutrients generated on the sunny side. Mauna Kea has insects living on its glaciers that eat the freezing bugs blown up from below. Glaciers several miles thick would form on the dark side and would flow towards the sun, where they would melt and continue the cycle. [Answer] I think that in a tidally locked planet, the night side gets cold enough that any atmosphere freezes, and ends up frozen on the ground. On the hot side, any liquid would eventually evaporate and, along with any atmosphere on that side, will eventually make its way to the dark side, where it would permanently freeze in place. Even at the terminus, and even if the planet wobbles a bit, every molecule that can get off of the ground in the warmth, will eventually get permanently deposited onto the cold side. So, a tidally locked planet is a planet without any atmosphere or liquid anywhere on its surface. The only possible place for life to exist would have to be sealed underground. The above means, that some NASA scientist is likely to say, "There is a 100% certainty that life is there". ;) [Answer] I liked Cadcoke5's comments that anything volatile would generally end up on the dark side, but there are even worse implications of a tidally locked planet. The spinning of our planet, coupled with the convection of the molten core (which is heated by decaying potassium, thorium and uranium isotopes) powers a magnetic field. This field keeps the solar wind from stripping our atmosphere and water vapour from the planet. A tidally locked planet would become more barren than mars (which has such a thin atmosphere that liquid water can not exist and even if it was pure oxygen, you would die in seconds). It may take a while to dry up by our standards. I don't know if this would be 10 million years or a billion years but compared to the 3+ billion years our planet already is, it is instant death. ]
[Question] [ Would copper-based blood be viable for a human-like land-based species in an earth-like atmosphere or would it be worse than iron-based blood? [Answer] No, it would be less efficient. Hemocyanin [is a protein that transports oxygen in some invertebrates](https://en.m.wikipedia.org/wiki/Hemocyanin) the “blood” of animals that contain this protein, such as horseshoe crabs is blue when oxygenated because of the copper present in the protein. Hemocyanin is substantially less efficient at carrying oxygen compared to hemoglobin (what you have in your red blood, assuming you’re not a sentient horseshoe crab or octopus). Therefore a copper based blood would be less efficient if we look at the real world examples of copper based blood as a reference. Hemocyanin is more efficient at lower temperatures and lower oxygen concentrations than hemoglobin, which is why it is present in animals like cephalopods, crabs, lobsters and other denizens of the deep. Hemocyanin would not be sufficient as an oxygen carrier for any vertebrate breathing earth’s atmosphere. [Answer] > > would it be worse than iron-based blood > > > Yes, as NixonCranium's answer states. Haemoglobin is a more efficient carrier of oxygen, so for equal concentrations of oxygenating compounds in the blood, haemoglobin is objectively better. > > Would a copper based blood be viable for a human-like land-based species in an earth-like atmosphere > > > This is a very different question to checking what works best. Evolution moves incrementally into the "adjacent possible" solutions, so once a body plan is substantially committed to a solution, it's not often that you see evolutionary pressures to reverse that. More typically, what you end up with is further layers of adaptation to push a non-optimal solution into something which works for a new ecological niche; and evolution is a surprisingly good way to make things "viable". With aquatic mammals, we actually have interesting examples of evolution going in the other direction. Hemocyanin is objectively better for deep-sea dwellers, but whales have evolved a blood supply with twice as much haemoglobin which allows them to dive to similar depths. It's easy to see how successive small increases in haemoglobin concentration would give animals an advantage in feeding range. There's no reason to think that the same would not be true for animals with copper-based blood. If there are no haemoglobin-based animals already occupying that ecological niche, it would actually be surprising if something else *didn't* move in. Animals who can expand their feeding range further towards the surface would have a clear advantage over those who can't, so it's easy to see how they could evolve more concentrated blood to deal with the environment. And from there, animals who can make more use of the feeding or nesting opportunities on dry land would again have clear advantages. This doesn't mean that it would be the objectively best solution, any more than a whale's haemoglobin concentration and air-breathing are objectively the best solution for life in the depths of the ocean, but it's perfectly well within the bounds of what could be evolutionarily viable. ]
[Question] [ The Dwarves, they mostly live within their mountains while a wealthy but small percentage of them own land on the surface. They are very isolationist preferring not to take sides when conflict arises unless it directly affects them. The Hierarchy of the society in question is as follows: * The Tsar - He is the sole ruler of his vast underground empire. The position is passed on to the oldest son when the Tsar dies. * The Council - A council which makes decisions on matters beneath the Tsar and consists of a single appointed noble from each of the clans. * The Nobility - Wealthy clans of varying power and size that have held power for many generations. The most powerful clans swearing direct fealty to the Tsar while the smaller clans swear fealty to the various greater clans. What makes them a part of the nobility is the fact that they're clan has a seat on the council and able to cast votes on decisions. * The Boyars - wealthy non-nobles who own some mines and land but don't hold much power themselves and have only had their power for one or two generations along with nobles who've lost their seat on the council. * The Merchants and Tradesman - The ones who own businesses and work in accordance with the Boyars. * The Common Folk - The ones who work the land and mines for the Boyars and nobility. The group of extremists in question wants to get rid of the nobility and the Tsar while also taking control of the mines and owning the land on the surface, and after achieving these goals they also plan to invade the surface and expand the Dwarven people beyond their mountainous homeland to greater territory on the surface. The tech level is around late 16th century with some technology of the Dwarves being ahead in some regards with the beginning emergence of snap lock muskets. The humans on the surface however only have tech equal around the end of the 14th century due to slower development on their part and also due to the Dwarves restricting trade and knowledge of their technology with them. How could a group of extremists overthrow and drastically reform such a society? EDIT: More information because there has been a question on how this group is extremist. The extremists are a group which is very anti-Nobility and want the people, the common folk, to own the mines and land they work and not be merely content with their lives. They also believe that the dwarven race as a whole is superior to the humans and even the elves because of their technological advancements. They believe that the nobility is holding back their people's true potential and by being rid of them they can then usher in a new age of progress for their people by invading the surface and establishing dominance upon the world above. EDIT: To Clear up some confusion over my use of the term "Boyar" and what differentiates them from the regular nobility. Summarised, The nobility have seats on the council and the Boyar don't, Among the Boyar are disgraced nobles who've lost their seat and thus are no longer considered nobles by the other nobles, and there are also families who've only owned land or a mine for one or two generations and don't have a council seat. Additionally, if a Boyar gains enough influence they may be able to petition for their family to have a council seat, which would make them nobility, and the nobles may decide to have a vote on whether or not they may have a seat. The Tsar may also grant a council seat to a Boyar for whatever reason he wishes. Votes on the council are settled on a 6 to 10 majority basis. [Answer] Find some neglected prince who is somewhere between 5th and 10th in line for the Throne, but is disrespected by other royalty for some reason (maybe even for their interest in outside world). Get him to conspire with you. Conspire with a few powerful clans, by promising them even more riches and power from conquering human land. Ideally candidates are clan that is rich enough to produce an army, but lacks political power or respect. Start spreading rumors that humans want to invade dwarves and steal their riches. If necessary, hire some human thieves or bandits to do just that. Stage a coup-d'etat, killing every royal so your pocket price becomes Tsar. Use armies of the loyal clan to prevent other clans from taking power for themselves. Attack and kill the clan that is leads the opposition, redistribute their lands, mines and riches to loyal clans. Repeat until opposition ends. **PS Your political system is overly complicated**. Boyars are same as Nobility, and defined by ownership of land (including mines), which is the only source of power in medieval settings. Power means army, which requires money or resources, and these come from land. You can have different levels within nobility (Game of Thrones is a good example); IRL boyars were the top non-royal level. The next-powerful class are merchants and craftsmen, who own the technology and skills to create or deliver goods. Industrial revolution meant that technology became more valuable than land. [Answer] Start a religion. It may take longer than you prefer but it works. If the nobles see it as a way to keep the workers in line (and too busy to think about rebelling) they'll not only approve of it but they might even donate some resources, like meeting space or even salaries for the clergy. If you're lucky, the nobles won't want to come to services. Then you have safe ways to meet up and spread information among workers. And you can start organizing. Slowly, the religion will start amassing more and more power. At first they can justify this by taking the burden off of the nobles. For example, they can take care of feeding workers who are sick or injured or survivors of dead workers. Then, without the nobles having noticed the transition, they're suddenly in charge of food distribution to workers in general. Then to other parts of society. Then the nobility realizes the religion is in charge of everyone's food. But it's okay because the religion is neutral and benign. For now. [Answer] Your revolution is missing a strong base and since your dwarves seem to share some common ground with the old Russian Empire, I'll give you a simple alternative: Dwarf [Rasputin](https://en.wikipedia.org/wiki/Grigori_Rasputin). A charismatic religous leader can be the center of your extremist movement, as Rasputin did, your leader will proclaim himself (or herself, she can be Drawf [Joan of Arc](https://en.wikipedia.org/wiki/Joan_of_Arc))a holy person or a messenger of the Gods. But they will side with the Common Folk instead of the Ruling Class. If you add some repression and corruption you can get a valid [revolutionary situation](https://en.wikipedia.org/wiki/Revolutionary_situation) and your extremists will have a chance at success. **EDIT due to OP EDIT** What you've described is within the causes of a Revolutionary Situation. Given the state of technology and assuming religion is part of the status quo (ej. The Tzar has been ordained by the Gods) an strong religious (with a political agenda) leader can be the engine that launches a Civil War that overthrows the goverment. [Answer] *Lie. A lot.* What you're doing is essentially a scam. Instead of scamming people out of cash, you're scamming them out of their country, but the same principles apply. Put pressure on your marks until they're not thinking clearly, then suggest what you want them to do in such a way that they think it was their own idea all along. Start with a generous amount of fearmongering. Make sure that your people believe that the humans are horrible terrible people, the worst sort of barbarians, ready and willing to invade your lands, slaughter all good, honest, hard-working dwarves, and tear down dwarven society as a whole. Repeat this until they *really* believe. In fact, things will generally go better for your rule if you just don't ever stop propagandizing. Eventually, someone (presumably a councilor or the like, unless your society has a separate professional army, which it probably doesn't) will get put in charge of fixing the "human problem". Make sure that someone is sympathetic to your cause. It's great if they're a card-carrying member of the Invade the Surface Party, but control through e.g. blackmail or bribery can be effective - just make sure they don't slip their leash, so to speak. If the chosen councilor or general *isn't* yours, and you can't make them yours, have them removed by whatever means are necessary: blackmail, character assassination, regular assassination, backroom politics ("if you let us take the lead on the Human Committee, we'll support your bid to lead the Farming Committee"). Continue until someone sympathetic to the cause gets the job. This may cause a fair amount of havoc, which you should take every opportunity to blame on the humans and/or wishy-washy, ineffectual councilors. Once you're in charge of fixing things, have your confederates spread rumors that everyone else is wishy-washy and lax on the subject of the humans. This works doubly in your favor, because in addition to eroding popular support for the other nobles, those nobles will be encouraged to contribute generously to defense in order to save face... but you control all the defense efforts, by the Tsar's decree. Play your cards right and your enemies will hand you all the power you need to dismantle them if the time comes. Throughout all of this, the pace and excess of your propaganda should increase. You're not satisfied until the public well and truly believes that the humans need to be, if not crushed, at least denied with all possible force ("crushed" is more helpful when it comes time to implement the second part of your plan, invading the surface). What happens next is up to the rest of the government. It's possible that they will willingly cede you the power and resources you need to carry out your invasion plans. If so, you win! If your invasion goes well, the wealth and lands you seize will help secure your position when the nobles get uppity again. If it fails, well... don't fail. More likely, the nobles will buy into the threat, but insist on "helping" solve it - some with good intentions that just happen to conflict with yours, others with selfish motives. In either case your goal is to use your position as the final arbiter of all things human-problem-solving to paint them as misguided or treasonous, and have them sidelined, exiled, or purged (adjust to taste, and keep in mind that they may be assets in the future if handled correctly). Eventually the council will shift to a composition that will give you power as above. The last option is that the government will do nothing, refuse to be baited, or even rebuke you for your efforts (and/or political grandstanding). In that case, your job is much trickier: you'll need to use the fear and anger you've instilled in the population to launch a coup, aided by whatever hardliners you can scrape together among the nobility. (Don't forget to shore up your support by offering people generous rewards after your victory. You can even promise to promote upstanding commoners to a newer, more effective council of nobles, if that's what it takes to get them to storm the barricades for you.) There are a lot of ways this can go wrong, and you may find it more advantageous, not to mention safer, to simply wait and continue to apply pressure. [Answer] OK overthrow a government. *nothing easier as that ...* First you need a plan, the plan what you want to do if you would lead this country. You need to convince others you're right. When you are getting opposed by the government (from your position illegally or unmorally) , because you're too extremistic it comes to the turning point of the whole story: **You need a strong supporterbase to make a big revolution** When you have convinced more than a quarter of the common people you have a power to be recogned with. If you have half you can successfully make a civil war with your supporters and with that split up succesfully from the government. When you have more than half of all people convinced, up until more 3/4 you can win a civil war easily, even against the army. when you have very many more than 3/4 you have already overthrown the country and won the not even started war. So whatever you do, you need to be backed by many people. Meaning you need to be good in convincing others EDIT: You show up a (or more) fault(s) of the nobility. Like oppression. Then you spread the rumors about the storys common people happened. Make sure everyone feels the oppression could hit him/her self, that everyone is threatened. People will rumor more and fears consolidate. The turning point is another fault by the government, which lets everyone jump up and raise their powers to get rid of the nobility. And then follow above - every "fault" can be government made or put the blame on the government. [Answer] Your revolution will be the product of Dwarven, not human, thinking. An underground mining culture will never use nor value rifles. In a world where every building is bulletproof, a world of tight spaces and short sight lines, an innovation in long range piercing weaponry will be greeted with disinterested shrugs. The weapon of choice in brutal underground fighting is strategic suffocation- controlling flames that suck the air from the tunnels, and directing choking smoke down others. Dwarven defensive thinking is focused not on controlling access to a space (which is easy underground) but on maintaining life support to a space (which is hard). The Nobles and Boyars don't control the mines and land above- they control the air and water pipes that connect them, and they control the mining winch rooms, and the doors that swing shut in the event of a mine fire. Or a riot. The innovation that suddenly makes revolution possible and changes the power equation is explosives. Young PowderMasters mastering the mining techniques suddenly make whole new areas quickly and easily accessible. New frontiers open up, ones not previously controlled by the old regime. At the same time, Those PowderMasters recognize the obvious military applications of their skills. By banding together, they can share their art with each other more easily, and restrict access to others. This guild is the start of their secret society, and shared power makes for ambitious plans. And how will they keep control of this brave new world they are creating? A blasting charge can just as easily remove an air access pipe as it creates one. Easier, really. [Answer] As history taught us multiple times : **Convince the poorest(the common folk) to carry out a revolution** and destroy the entire hierarchy, making the people love and later elect you their leader. Enforce their feeling of patriotism and nationalism. Tell the people how unfair this hierarchy basically is, and propose the only possible solution - killing all the current leaders and council members to later "democratically" elect a single leader who will lead the dwarves to prosperity. *In the late 16th century, I guess that wouldn't be hard - speaking of history, think of the french revolution; the french people were - technologically - quite similar to your dwarves. They too had just discovered explosives etc., however also including cannons, so it should be far easier for your dwarves then it was for the french people back then.* *Worst case : The noble men have all the weapons. At first try to convince the soldiers;if this doesn't work, start a guerilla war, and starvate them.* But you can be sure they will elect you, because you were there leader back in the revolution, and also know how to influence the people. However, make sure to *stay in the background* as long as the hierarchy is still alive - else they may kill you - the leader - before the revolution gets a chance to suceed. *Finally, build up your own hierarchy, and see how long it lasts...* [Answer] You need some kind of power base to start a revolution. In a medieval setting, it might be hard to incite the common folk to revolt. Having essentially no weapons, and being poor, they have very large odds against them. Consider Russia; there were multiple uprisings of serfs in Russia, but none overthrew the tsar until the Russian Revolution, which was well after the medieval period. But there are alternative routes to a revolution, some of which might make more interesting scenarios an uprising of common folk. It's possible that the merchants, tradesmen and boyars are very unhappy with the situation. Say they control nearly all of the economy, but have very little political power. If they are disaffected enough, they might be induced to revolt, and if together, they control enough resources, the revolution might be successful. And then, in the chaos following the revolution, your conspiracy of extremists could seize the power from the merchants, tradesmen, and boyars. (Think the Russian Revolution, where the Bolsheviks ousted the other socialist parties and took all the power for themselves.) And they could unite the dwarves by starting an expansionist campaign on the surface. (Think of the French Revolution, where Napoleon raised an army and conquered half of Europe.) Finally, they could double cross the merchants, tradesmen, and boyars, eliminate all the elites, and try to raise up the common people. (Examples of this might be during the French Revolution and the Chinese Cultural Revolution.) [Answer] Totally different attempt : **Blackmail the Tsar.** Everybody has something valuable. Control him from the background. When you notice him slightly considering the possibility of reopposing, force him to state that **one of your men was a secret son of him noone knew**. Then assassinate him and his children. You will have the next Tsar. *Now start widening your power and dominating the council & later country ! Convince the people that you are the leader of the poor. Also, portray the other races as the "real threats" for your "glorious race". Use propaganda.* ]
[Question] [ **Closed**. This question needs to be more [focused](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Update the question so it focuses on one problem only by [editing this post](/posts/96765/edit). Closed 6 years ago. [Improve this question](/posts/96765/edit) You see it in movies: an invading entity is unstoppable with conventional weaponry and a desperate leader is forced (after much soul-searching) to detonate a nuke against said invader as a last ditch effort. So my question is this: given the sudden appearance of a large alien creature (along the lines of a kiaju/Godzilla/Cloverfield kind of thing) plus a host of smaller accompanying creatures that are all extremely resistant to conventional weapons and going on a massively destructive rampage across the Swiss border and into France, what would the weaponry escalation path look like and at what point would the French President finally resort to the deployment of a nuclear weapon? Or is this the kind of thing that would never actually happen? I hope that is a clear enough question... [Answer] There are a lot of alternatives to nuclear weapons which are not explored in movies because the choice would be rather anticlimactic. Remember that these movies ***rarely*** make any sense; it's all about shock and awe, not logic. Consider that a flesh and blood creature is going to be severely damaged by an explosion in real life, unlike movie monsters which are conveniently immune to armor piercing tank shells, napalm, etc. First things first, this giant creature would be targeted by air strikes, and maybe face ground armor capable of delivering punishing ordinance. Have you ever watched a movie and heard the main character yell into a radio: > > "Coordinates X, Y, Z, this is ***danger close!!!***" > > > That's because the shock wave of an explosion (or the resulting shock wave from the impact of a kinetic projectile) can kill a human being. It's called [**hydrostatic shock**](https://en.wikipedia.org/wiki/Hydrostatic_shock_(firearms)). You never see Godzilla worrying about that in the movies, but in the real world that's something we're quite mindful of. Also keep in mind that we are experimenting with Gauss cannons which fire square blocks of metal because aerodynamic ammunition would actually ***go too far***. You know it kicks ass when that becomes a concern. And while there's severe limitations to the technology today, that will likely not be the case in 10 years, and I'm sure some exceptions could be made for an emergency situations. Anyway, moving on. If for some reason regular ordnance proved to be insufficient (perhaps because there are a lot of parasitic monsters following the kaiju, which would difficult to wipe out in street to street fighting), there exist air fuel bombs, and other truly scary weapons which can deployed, and which are capable of wiping entire towns off the map while not being nuclear. Only if these things failed would nuclear weapons even become an option, and most likely because there's a concern about some sort of contamination which might be killed off by the radiation fallout. To my mind, that would actually be the best reason to deploy nukes in the first place. Imagine a giant monster rampaging through the streets of a metropolis. Sure, the monster is dangerous, but it's blood may be toxic, and there may be parasites which stream off of it, and which are actually a bigger threat than the Kaiju itself (think [**Cloverfield**](https://en.wikipedia.org/wiki/Cloverfield)). A nuke would solve that problem nicely. Kills the monster, and irradiates the heck out of any biological material left behind, killing any bacteria or viruses. Of course the collateral damage may be quite high, but it all comes down to a cost-benefit analysis. DO you risk these things getting out of the city and having to hunt them down for the next decade, or do you turn New York to cinders? And of course it's always New York. [Answer] The weaponry escalation would be local civilian weaponry such as shot guns, followed within minutes by police weaponry including machine guns. There would probably then be a pause. The situation would then rapidly escalate up the chain of command in the police force and at some senior level escalate into the political arena via some emergency procedure being triggered. The Government leadership would be briefed on the situation within hours and further emergency procedures in place for terrorist attack would enable the armed forces to be activated. Depending on the exact situation on the ground and the proximity of the nearest available ground forces, the air force would probably be used next attacking with missiles and bombs within hours or possibly the following day depending on the time of day when the alert was first raised. By the following day ground forces should start to arrive in quantity and engage the enemy together with attack helicopters and a lot more fixed wing aircraft from bases all across France. Given the French view on defence and the suddenness of the attack I doubt that any foreign forces would be asked or allowed to be involved. After a few days a significant build-up of conventional forces would be available in the locality, including large numbers of infantry with conventional weapons such as rocket propelled grenades, machine guns and mortars. This would be supplemented by armoured forces and ground launched surface to surface missiles to engage the enemy in strength. If these forces were defeated then I imagine the French president would be forced to use nuclear weapons. The first nuclear weapons used would be tactical (if the French have these). If these were unavailable or ineffective then larger nuclear warheads would be used. It is impossible to say what the time span would be. It would depend on the exact location of the enemy, their numbers, the damage they had caused, the size of the area damaged, the speed of the damage, the number of people in the immediate vicinity, the effectiveness (if any) of conventional forces and other factors. I imagine it would come to a head quickly maybe a week or two, perhaps less. [Answer] **I think the first logical question would be "are they even affected by extreme heat and radiation"** After that, detonating a nuke over ones own soil is a rather personal choice. Detonating a nuke over another soil would be a very difficult choice because its virtually an act of aggression. Would they do it? sure but they would have to know its effective and that there is no other alternative and that the enemy spread is uncontrollable. As for progression. They would likely try chemical weapons before nukes. MOABs would be a good determiner of whether or not a nuke is even viable. [Answer] A nuke would be deployed when the cost of life of not deploying it far outweighs the cost of deploying it. Large monsters aren't really a problem because there are so many non nuclear weapons that could be deployed long before having to resort to the nuclear option. Monsters would have to be extreme to warrant nukes. The threat really needs to be to the global scale of wiping out all human life or at least a good sized chunk of it to warrant it. A disease is the most likely thing to get nuked. Anything like the zombie virus from Resident Evil or World War Z would be nuked at the first sign to burn out the infection. [Answer] **GOOD NEWS!** Plans/protocols for usage of nuclear weapons on home-soil against invading forces already exist! The geological features and proximity to/density of civilian population determines if a nuclear weapon can be used... and what size. Two examples: * Sparsely populated mountain region can use a rather sizable yield weapon. * Paris is a "no nukes allowed" area. To me, this means that the escalation to nuclear weapons could be extremely fast if the kaiju is coming from mountainous regions and conventional weapons (JDAMs, MOABs) prove useless. Additionally, I feel that if the kaiju is known to be aggressive and is moving fast through the mountains, escalation to nuclear weapons could be near instantaneous; The plans to use them in this type of scenario **are** in place. (I did my English 102 report on nuclear weapons 20+ years ago. Primary reference was a 1970's US House/Senate report.) [Answer] I'm running the risk of adding not an answer (as real life rarely considers kaijus) but I would like to add some real world info in addition to Michael Kutz's answer. In the wonderful/scary (take your pick) book 'Nuclear Nightmares', Calder investigates the disposition of nuclear forces during the early half of the Cold War. The part that springs to mind is the section where he talks to US nuclear technicians deployed to Germany with 'tactical' weapons, designed to counter the wave of Soviet ground forces imagined in a possible invasion of Europe. The parts that stick in my mind are that he defines the difference between a 'tactical' and 'strategic' nuclear weapon as; > > Whether it is intended to be detonated in Germany or elsewhere > > > and that the US nuclear techs were complaining that; > > The German villages were at most '2kt apart' > > > meaning that 2kt was the largest yield they could safely use without large damage to the local civilian populations. So to attempt to answer the question directly, there is a long precedent of nuclear weapons being part of the generalist arsenal available to field commanders in Europe, to be used on home soil. In the specific example of a kaiju I would expect the use of the smallest yield weapons possible, to be used in areas of sparse population. Nuclear Nightmares: ISBN 0563177403 [Answer] Nobody has mentioned using a neutron bomb, which I think is the answer here. It sounds like France doesn't have any, but they could borrow some from another country or modify existing nukes. If damage, heat, and concussion from conventional weapons isn't working the next level is radiation. A neutron bomb is designed to give off as much radiation as possible at the expense of the blast radius. The US developed them to be used over friendly territory to stop the advance of Soviet troops without destroying the infrastructure like roads and buildings, but after human rights protests Europe didn't want anything to do with neutron bombs so they may not have access to them with short notice in real life. [Answer] The resonable escalation path would include two stops that haven't been mentioned yet: ## Fuel-air explosives A fuel-air explosive is a large conventional weapon that is basically just a lot of fuel. As it doesn't carry its own oxidizer, it uses oxygen from the air. This means the plane doesn't need to carry the weight of the oxidizer, and there's a lot of fuel that will turn a lot of oxygen into a lot of flames. Your large creature can't rely carry a nuclear reactor (no cooling circuit) so it must breathe - and after being on the receiving end of a fuel-air bomb, it will be breathing in fire. This tends to be rather fatal. ## Bunker busters Modern bunker buster bombs are designed to penetrate into armor and explode on the inside. This can be quite damaging as the sort of armor that keeps shockwaves *out* is also quite good at keeping them *in*. There might not be a lot of visible damage on the outside, but the inside of the target will be turned into a fine puree. Note that the latter weapon would initially be armed with a conventional warhead, but the escalation path would be to use a nuclear bunker buster. Having the nuclear weapon go off on the inside means that even a very small weapon (<1kt) would turn the thing into small chunks of radioactive meat. Sounds bad, but it does restrict the fallout. ]
[Question] [ I am living in a society which considers autonomy over one's own death a basic human right. That means killing someone is very, very bad, no matter the circumstances. Our society is strictly against the death penalty, and also opposed to law enforcement using deadly force. But at the same time we believe that everyone should have the right to end their own life through suicide if they choose so. I was tasked with designing a maximum security prison for the worst of the worst criminals of our society. Most are convicted to multiple life-long sentences. The human rights activists want to make sure that the inmates have the right to commit suicide. The politicians also agree: Keeping someone in prison is expensive, so the earlier they die, the better for the tax payer. But most inmates are very dangerous and inmate-on-inmate violence is unfortunately very common. How can I design a way for inmates to commit suicide which can not be abused? * The suicide method must be available to all prisoners. When a prisoner sincerely makes the decision to end their life, they must be able to do so within 24 hours. * Inmates must be unable to physically force another inmate to commit suicide (driving someone to suicide psychologically is something different, of course) * Inmates must be unable to use the suicide method to injure someone, use it to escape, smuggle contraband or compromise the security of the prison in any other way. * Prison personnel must not assist with the suicide, so just asking to be executed is out of the question (assisted suicide is only legally possible when a person is physically incapable to commit suicide due to a medical condition) * The guards are trained and equipped to subdue inmates with various non-lethal methods, so provoking a guard to shoot them won't work either. * If possible, the suicide method should be humane and painless. * I am on a budget, so nothing which is so elaborate that the cost would be prohibitive. Tech level: present day. [Answer] A suicide booth It should be activated by a fingerprint/retina scan or something like that, after activation there would be a time to decide (few hours) to avoid forced activation/give some more time for the inmate to decide. The person gets locked in, guards are notified to check if the activation was not forced, and then it gets filled with helium for painless suffocation. [Answer] You don't have to design prisons to facilitate suicide. The suicide rate in prison is always extremely high. Prisons have to be designed to prevent prisoners from committing suicide. There are procedures to prevent prisoners committing suicide. The answer is easy. Read the literature on how prisoners commit suicide and make sure the features and methods for suicide are readily available by the score. Make sure those features are such that prisoners can commit easily. You don't need special facilities, gadgets or poisons, special rooms or whatever. Let prisoners keep their belts and shoe laces. Ensure there are lots of hooks and do-hickeys for attachments or clothes hooks or similar and they'll do the rest. This is part and parcel of what happens in prisons in the real world. There's no need to fantasize about adding death dealing devices. Prisons are killing machines enough. They drive their inmates to self-destruction. If you want prisoners to suicide, just look the other way and they'll do the rest. Most of the other answers seem to be written by people who haven't had to look into the abyss. This in some ways is your good fortune, but it robs you of the understanding of the terrible price even the loss of a single human being bring in its wake. [Answer] Maybe you shouldn't give that freedom to inmates. Prison serves three purposes: **Rehabilitation.** Let there be said that a prison that doesn't rehabilitate is a prison that does not work. **Imprisonment.** For people who pose a threat to society, imprisonment serves to protect said society. **Punishment.** Prison strips inmates of some of their freedoms and rights. Freedom of circulation, obviously. Depending on your jurisdiction, it could also include voting rights, freedom of speech, etc. In a country with euthanasia, then it may include the right to die. If you give inmates the right to die, you give them the right to reduce their punishment, which defeats the core purpose of prison. You have to remember that they are in prison because they (were convicted of having) wronged society, i.e. there's probably someone out there who lost a loved one because of them. You should ask yourself if allowing suicide isn't giving them a "get out of jail free" card. --- Now about how to make suicide happen regardless, keep it simple. You need a room and a pill. Inmate asks to go to the room, eats the pill, then dies. The inmate can back up at any time. You may add a psychiatrist in the loop for good measure, if you have the budget and personnel. This fits the criteria of being a conscious decision, available to all, unable to hurt anyone else. The weak link may be supply, particularly if pharmaceutical/chemical companies estimate it's inhumane. See how some US states reintroduced old death penalty method because they couldn't procure injections. [Answer] What about just having a room with a pistol in it? When a prisoner asks to commit suicide the guards will escort them to that room and come in to remove the body after he's dead. If it's a problem that the prisoner may steal the pistol, assault the guards and go on a killing spree with it you can fix the gun to the wall with a remote trigger. The prisoner stands in front of it and presses the button. There can be a glass window (not in front of the gun) for the guards to check if the prisoner really killed themselves or just faked it by shooting without standing in front of it. If the prisoner didn't commit suicide correctly and just got a heavy wound, the guards can enter and shoot him (the prisoner is incapacitated in his ability of killing himself by the previous shot and they clearly stated their intent of killing themselves earlier). Neither option should be particularly costly. The biggest expense probably is the extra room but that can be offset by using a rarely-used room and designing the window into it (if the original room didn't already have one). Firearms should not be a problem, if these are so rare because everyone uses non-lethal methods replace firearm with a dart gun that uses deadly venom instead of something that merely knocks out the victim. A sightly more costly option would be a fixed station the arm is held into. After the arm has been inserted the station will inject the venom. This also removes the problem of accidental non-suicides. [Answer] Just have an air chamber available that will not close with more than one person inside. Have a computer terminal, that only operates with the door closed, that will release nitrogen when the prisoner types out a randomly generated phrase on the keyboard. (A second measure to prevent murder and also serve as a indication of intent by the prisoner.) Patient lies down on a mat or bed and dies. No idea what the cost of gas vs. lethal amount would be. I suppose you could cheap out and make the air chamber a hyperbolic chamber... but it might be less humane with the ear pressure, increased temperature etc. [Answer] Attach something with a poison in it to a part of the inmates body. On a voice command, it can open it and the poison will flow. With voice recognition, that should avoid being able to cheat the system and kill someone. [Answer] Low-tech: one deep elevator shaft and an openable door onto it. No mechanics or poisons to go wrong. And you probably needed an elevator anyway, so the extra costs are low. This has the advantage that there is no weapon or other contraband to steal. (If you're not concerned about prisoners keeping their belts or other rope-like items, use [this answer](https://worldbuilding.stackexchange.com/a/50897/28) instead -- prisoners in our world use it already so we know it works, and you don't have to build anything special.) Access to the jump site needs to be controlled; it must not be possible for a prisoner to push someone else off. So, most of the time, this space is the resting location of the elevator. When a prisoner wants to use his suicide option, a guard escorts him through the locked-and-alarmed door guarding the site, uses his key to send the elevator up and then disables it, and waits. When the prisoner has either jumped or decided not to, the guard returns the elevator to service, locks the door behind him, and resets the alarm. The purpose of the alarm is to alert guards if, somehow, a prisoner manages to gain access to the door with intent to push someone else. Even if a prisoner reaches the elevator, he'll need a key to deactivate the elevator. And he'll only have a short time to improvise, because guards are responding to the alarm. [Answer] Assume that in this society that some of the keys to total body control have been mastered and the knowledge is no longer solely in the hands of mystic monks in Shambala or whatever. We know yogis and martial artists can do some extreme stuff with their bodies. Hypnotically implant a mental routine that controls breathing and panic responses. this hypnotic routine is subliminal, so that the panic control that would create super soldiers is not easy to access by the prisoner. The breathing routine doesn't just slow, but actively stops breathing altogether. With the panic response muted, this becomes about as humane a way to go as possible. Now, give each prisoner a randomly generated nonsense phrase or other triggering mechanism, unique to each prisoner, that triggers these 2 routines at the same time. This way, each suicide cannot be forced by another person, does not not leave messy residue, other than the corpse, and does not require additional resources, rooms, or other stuff that can be abused. It does not require a guards interaction, and would be available to even a quadriplegic. Since this method is hard to circumvent and be abused, you can create a really fun villian, because they'd have to be very clever, and clever villians are the most fun :) ]
[Question] [ Suppose that there's a button at the other end of the universe, and a 'stick' that goes all the way there. If I push the stick, will the button get pushed instantly, or there is some latency that I am missing? (Suppose that the stick is made from whatever strong enough material that can stand whatever physical or practical constraints over there.) I want to use this mechanism to build a real-time communication system that spans multi-light-years areas. So is this a good idea? [Answer] The pressure allowing the stick to move when pushed at one end will move at the **speed of sound** in that material. Imagine the rod is a [slinky](https://en.wikipedia.org/wiki/Slinky). Understand springs ([Hooke's Law](https://en.wikipedia.org/wiki/Hooke's_law), etc.) and you understand solids in general: they are just orders of magnitude stiffer. It might be more philosophically correct to note that a spring is just like any solid rod, just wimpier. A wall resists pushing because it [*compresses*](https://en.wikipedia.org/wiki/Compression_(physics)) by some invisible amount. When you apply a compression stress to a solid sample cylinder [it gets shorter](https://en.wikipedia.org/wiki/Compressive_strength) and the force pushing back at you is proportional to the change in length. When that force balances the load the column is in equilibrium. Picture a concrete piller as being **exactly like a bedspring** except for the size of the constant: the concrete compresses by micrometers. [![concrete tester](https://i.stack.imgur.com/uqOYu.jpg)](https://www.youtube.com/watch?v=eAUfJ90QtDY) I’ve seen video like the concrete strength tester above, but with a micrometer (pictured below) in parallel with the rock sample. You could clearly see that stress (force squeezing the column) and strain (the *change in length*) were in sync until something broke. ![dial](https://i.stack.imgur.com/VTY8G.jpg) It’s all a matter of the scale of the compression relative to the size of the member, and the human perception scale. Imagine a short rod of steel the size of a pencil. On this scale you find it *hard* and unbending. But, it's really a sample of a product sold as *rope*! It comes in spools 10 feet in diameter. For a length of a bridge span, it wobbles and is obviously ropelike. Conversly, if you have a steel I-beam a mile long, and you push one end hard enough to shove it, you will note a delay before the far end moves, and the length shortens like a piece of rubber, compressing first, and then the wave of compression moving to the other end where that wave eventually causes the far end to move. The compression moves as a [logitudinal wave](https://en.wikipedia.org/wiki/Longitudinal_wave) in the solid, since the sample is long enough to make the [speed of sound](http://www.engineeringtoolbox.com/sound-speed-solids-d_713.html) (the speed at which the atoms react to their neighbors) slow in proportion to the total time involved. Radio would be *far* faster than mechanical linkages. ]
[Question] [ I recently came across [Could pulsars really act as "lighthouses" to help in interstellar travel?](https://worldbuilding.stackexchange.com/q/94682/627), asked a week ago. The author was trying to figure out if pulsars could be useful for interstellar FTL travel, because they could be used to find a craft's position; the answer was, of course, yes. I had some reservations, though. My main issue was that it seems, from an engineering standpoint, not very feasible. Here's my thought process: * To be certain of successfully triangulating your position to a high degree of accuracy, you'd need to have probably half a dozen or more candidates to observe from any one location. * Observing a pulsar isn't easy. The issue is that if you make a random jump out of hyperspace, you won't know where any pulsar should appear unless you can quickly determine a general location. This means that you'd need to do a lot of guessing, and essentially discover pulsars all over again. * This in turn means that you'd need a large radio telescope, and that's not really easy to attach to a typical spacecraft. Optimally, the dish is over 100 meters in length. Let's say that we overcome various other technical hurdles, and need to attach a 100-meter parabolic radio telescope (although I'm open to other designs, if you can make a very convincing argument otherwise) to an interstellar spacecraft, for the purposes of finding and monitoring pulsars for navigation. I'm concerned as to whether or not the telescope could survive sub-lightspeed travel for any extended period of time. By this I mean acceleration for perhaps two weeks to a speed of maybe $0.01c$, staying at constant speed for three months, then decelerating for two weeks. Propulsion would likely be from chemical rockets. * Will the telescope survive the harsh conditions of space, including micrometeoroid impacts? * Will there be any physical stresses from the motion of the ship that could damage it? * Are there any other potential dangers to the telescope itself, and can they be overcome? So far, nobody's actually addressed the original scenario in as much detail as I'd like. I'd love answers that do that; it's why I asked the question. However, I wouldn't be totally opposed to answers that suggest different but related options, such as using a different type of telescope, or using pulsars a different way. But you'd have to make a *really* good case for doing so, and you'd still have to justify that this option would survive the spaceflight. --- My motivation for asking this is that I've considered using pulsars for this purpose in several stories, but I've always gotten hung up on how to solve this sort of problem. [Answer] # A scintillation array + good computer = *synthetic aperture* Pulsars are not exactly discrete and quiet things. And radio telescopes do not actually need to look like in [the film Contact](https://www.youtube.com/watch?v=O9G5lrxTF6k). In fact... [the radio telescope that discovered the first pulsar](https://en.wikipedia.org/wiki/Interplanetary_Scintillation_Array) today looks like this: [![enter image description here](https://i.stack.imgur.com/0jS1i.jpg)](https://i.stack.imgur.com/0jS1i.jpg) *The Interplanetary Scintillation Array, Mullard Radio Astronomy Observatory , Cambridge, UK* Yes, those uneven poles and sagging wires are what first picked up the signals from the pulsar that affectionately became called [LGM-1 (Little Green Men 1)](https://en.wikipedia.org/wiki/PSR_B1919%2B21). So you do not need to cover your array with a big metal sheets like you see on parabolic antennas. What your ship needs is not a big dish, but a number of "whiskers". They do not need to be massive, they just need to be **long**, say up to 100 meters for a nice round number. Further helping this is the fact that you can "cheat" by having a computer compare the signals from each different whisker. By running some fast and fancy math on the incoming signals, you create a fake antenna that is just as large as if it had been a massive dish that has a hundred meter radius. This is known as a [synthetic aperture](https://en.wikipedia.org/wiki/Aperture_synthesis). And even if the gathered energy of the pulsar signals do not become as plentiful as it would be with a "solid" disk, the extreme angular resolution is such that it becomes easy to pick out the relevant signals from noise. So can a radio telescope that can listen in on "beacon" pulsars survive a space trip? **Oh yes, it can**. You just eject the drogue weights that un-spool the "whiskers", and soon you will have the bearings of all the pulsars you need to make an accurate estimate of your position. [Answer] You do not want your dish hanging in the breeze as you zoom about. You want it when you want it, and not before or after. You want an **Inflatable dish.** [![inflatable GATR dish](https://i.stack.imgur.com/H6xT5.jpg)](https://i.stack.imgur.com/H6xT5.jpg) from <http://www.gatr.com/products/4m-antenna-system> > > GATR has introduced an inflatable 4 meter-class communications hub. > GATR’s unique shape and design has enabled this high-capacity 4.0m > antenna that is 80+% less volume and weight than comparable sized > deployable rigid antennas (4 cases, less than 400 pounds total). > > > Your sleek, suave spaceship slips thru space. On emerging and desiring a fix on pulsars, the GATR-type inflatable radiotelescopes are deployed. They inflate to very large size, enabling rapid detection of the pulsars in question. After listening to the pulses (they sound good), you deflate the GATR radiotelescopes, pumping the inflation gas back into cylinders. The deflated GATRS are packed away and your ship corrects course and streaks away. [Answer] **Ignoring the amount of likely technological advancement between then and now** An instrument as specialized and large as a radio telescope wouldn't be kept open unless it was needed. The thing about space is don't you have to worry as much about structural engineering against gravity. So you can have very thin loosely supported structures that can sprawl out on demand. Currently in space this is taken advantage of all the time. When a satellite is put into orbit in most cases its solar panels are rolled out. When a probe reaches its destination its antennae is deployed. A radio telescope isn't much different from an antennae dish. This reduces the chance it will get damaged. [Answer] # X-ray pulsars From <https://www.seeker.com/how-to-use-a-pulsar-to-find-starbucks-discovery-news-1766499711.html> Apparenly x-ray pulsars are easier to see > > Or, you could look for pulsars that emit X-rays, a much brighter signal. X-ray antennas are also smaller and lighter, says physicist Richard Matzner at the University of Texas at Austin. Their drawback is oversensitivity to electrons surrounding the Earth. > > > But an X-ray–based positioning system could pinpoint an object to within 10 meters, an improvement on the 100-meter or so accuracy of the radio pulsar system. > > > [Answer] The physical stress of motion won't be a problem. Every telescope on earth is built to sustain 9.8 m/s2 acceleration indefinitely. Accelerating up to 0.01 c (299,792,4.58 m/s) over the course of 2 weeks (1209600s) can be accomplished with a constant acceleration of 2.48 m/s2. Since this is much lower than what we engineer telescopes on earth to it should be easy to engineer a telescope to withstand that level of acceleration. [Answer] # Can a telescope survive micrometeoroid impacts? Data on micrometeoroid density is pretty sparse, and I wasn't able to find any. However, I think it is reasonable to use particle density as a proxy. We can get various particle density figures from [this post](https://space.stackexchange.com/a/2814/17340) on Space.SE, [this paper](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030053331.pdf) from NASA/Goddard, and a [selection of quotes](https://hypertextbook.com/facts/2000/DaWeiCai.shtml) about interstellar space here. The key here is going to be converting units. Lets put everything in terms of kg/m$^3$. From the Space.SE graph, we have about $2\times10^{-13}$ kg/m$^3$ at 550 km orbit, which is where Hubble telescope is. Solar wind density at the distance of Earth can be converted from particles per cm$^3$ to density by assuming a particle mass of $.002 / 6.02\times10^{23} kg$. The 0.002 estimate is due to most particles in space being hydrogen or helium. This gives us a near-Earth particle density of $3\times10^{-14} $ kg/m$^3$. This also broadly agrees with the numbers from Space.SE out at 1000 km altitude. Finally, for the interstellar density estimates of 0.1-1000 atoms / cm$^3$, we convert via the same method to a range of $1\times10^{-16}$-$1\times10^{-12}$ kg/m$^3$. Note that we shouldn't be seeing the higher end of the range except in [molecular clouds](https://en.wikipedia.org/wiki/Interstellar_medium#Interstellar_matter). Assuming we can steer our telescope clear of them, we should be traveling through space on the lower end of the spectrum. Mass isn't the only thing driving the potential for collisions; velocity is as well. What we should be really measuring is mass flux, the mass of particles we encounter per unit area per second. Now here it will be difficult to know for sure the velocity of particles in the direction of an object as it is hurtling through space, since this is a vector problem. So we will make some assumptions for best case for Hubble, and worst case for our telescope. Hubble is moving at roughly 8 km/s. Supposing the particles are not moving, we multiply Hubble's velocity by LEO particle mass density to get $8000\cdot2\times10^{-13}=2\times10^{-9} \frac{\text{kg}}{\text{m}^2\text{s}}$. For our telescope standing still in solar wind in Earth orbit, where solar wind has a velocity about 500 km/s, for a flux of $500000\cdot3\times10^{-14}=2\times10^{-8} \frac{\text{kg}}{\text{m}^2\text{s}}$. For our telescope moving at 0.01c relative to the interstellar medium (low estimate, since we are watching where we go), flux is $3000000\cdot1\times10^{-16}=3\times10^{-10}\frac{\text{kg}}{\text{m}^2\text{s}}$. So our telescope is seeing within an order of magnitude the particle flux that Hubble has been seeing since 1993. So the operative question is: has Hubble been damaged by micrometeroids? Well, Hubble did have a mirror replacement in 1993, but since then, as far as I can tell, the mirror was not repaired or replaced by any subsequent servicing mission, and Hubble is evidently working fine today. Which means that Hubble has had its fine optical equipment not (significantly) damaged in space for almost 25 years. From this, it seems the particulate threat to a giant space mirror is not significantly higher than it is for Hubble, and we can expect a 25 year life span, at least. # Can the telescope survive the acceleration? 0.01c is 3,000,000 m/s. Divided by two weeks gets you 2.5 m/s$^2$. Since this is less than 1g, it goes without saying that anything that can structurally survive being on planet Earth will also survive this acceleration. There are plenty of structures that at least 100m across. Perhaps the most applicable, some [Airbus A380](https://en.wikipedia.org/wiki/Airbus_A380) variants have a wingspan of 90m, so if it is doable with aerospace materials (i.e. aluminum), then it is practicable in space. Without any turbulence in space, I don't see any way that a telescope would need to be stronger than a large aircraft wing. # Any other considerations? I can't think of any. In general, I think we should consider the fate our of our outer planet probes. Of Pioneer 10/11, Voyager 1/2, Galileo, Cassini, and New Horizons, exactly none of them hit anything. From what I can tell, the primary difficulties (with Voyager 2, and Galileo, if I'm not mistaken) were radiation related. But those difficulties happened in proximity to giant radiation fields. Good solar system mapping should allow you to send your telescope into deep space without running into any unexpected radiation. # Conclusion From the evidence I have, I conclude that a large radio telescope could be moved into deep space without significant damage, and could be expected to operate for decades, at least, not even counting various improvements in space technology that could be expected in the near future. ]
[Question] [ Given that the surface gravity on the Moon is a fraction of Earth and there is virtually zero atmospheric pressure but I still want to wet our beloved moon with whatever liquid that is known to science. It can be liquid nitrogen or a cocktail of acids etc, assuming the present day tech level and the only handwavium is awarded to transportation of the liquid and nothing else how can we cover the entire (at least 95% of lunar surfaces) with liquid solution so that the shallowest depth is about 1 m for at least 1 year? (I'm trying to figure out how the new tug of war between a planet and its moon will play out.) **Clarifications:** * Money isn't an issue. * Foams are not allowed. * It can be any kind of liquid not necessary water [Answer] ## How much we need? Rounding down Moon to a roughly flat ball with the average distance to the planetoid center and then making a hollow sphere to the highest elevation via math gives us the estimated volume of liquid we need to fill. So: $V=\frac{4 \pi}{3}(R\_{peak}^3-R\_{sea}^3)$ Taking 1737.4 km for moon sea level, the [highest point](http://www.nasa-usa.de/mission_pages/LRO/multimedia/lroimages/lroc-20101027-highest.html) goes 10.786 km above that. This gives a volume of: $V=411722695.8934 \text{ km³}$ That only fills to *just* about the top of the highest mountain, demanding 5 km coverage, brings it to a generous $V=604296935.9922 \text{ km³}$, so your preferred solution is somewhere between those two extremes. In other words: it's a huge lot of liquid. If that would be water with a density of $\rho=1 \frac{\text t}{\text m^3}$, it would weigh ${4.1 \choose 6.0} \times 10^{16}\text t$. That is still much less than the weight of the moon (which ranges in the $10^{19}\text t$ area), but it is a considerable fraction: you would add about $\frac {1 \to 2} {1000}$ of the mass of the moon itself if you take water. Adding that much weight would have a substantial effect on the Moon-Earth system though, resulting in a decaying orbit and crash on a long term timescale, but that would be a better question for [Randall Munroe](http://what-if.xkcd.com/), who might dedicate that question of world destruction a blog entry. So I skip on that and go to what our ocean has to endure. ## Environmental Problems... Obviously, water will freeze due to being exposed to an environment of at coldest $26 \text K$ on the surface of the moon and $3 \text K$ at the surface to outer space. To complicate things, fluids start to evaporate much earlier (as much as close to $0 \text K$ for Hydrogen) due to reduced pressure. And above that, the Moon's surface gets very very close to $400 \text K$ in the sun, because rock is a very very bad thermal conductor. In the end, pouring all the water onto moon will just help in creating a jagged ice crust that more resembles an uneroded Europa than a liquid. Why uneroded? Europa encounters daily tidal forces, just like Tethys, which keep the inner water layers of the planetoid in a liquid state due to the extreme magnetic fields of the gas giants they rotate around. Earth can't grant that field - and both these snowballs have an outer crust of ice, not a fully liquid ocean, so the water solution is kind of out. ## What to take? So we got to take something that doesn't boil away, gets blown off the moon by the solar wind and doesn't freeze to solid by exposure to the temperatures. But here is the problem: there are not too many substances that are in liquid state in an environment facing to the $3 \text K$ and near vacuum environment of outer space... actually I could come up only one single material that actually is a liquid in an environment close to that: Helium boils at $4.22 \text K$ and remains liquid till very very close to absolute 0. it would weigh 0.125 tons per m³... but that is at 1 Atmosphere pressure, while we got a 0 atmosphere out at the upper edge of our ocean, which again... makes our precious ocean boil away due to reduced boiling point. Hydrogen (which boils at $20 \text K$) is not an option, as it freezes at $14 \text K$. ## End of the line No, you can't create a fluid ocean on moon, as it has neither a protective magnetic field (which would keep the sun wind away to allow the creation of an atmosphere and thus any pressure at all), nor is there a liquid that would be fluid in the whole $3 \to 24 \text K$ temperature range that we can expect on coldest point, and especially there is no substance that is liquid for the whole $3 \to 400 \text K$ range that we have to deal with on the day side. This does ignore the temperature averaging effect of the fluid though, but still: **No Atmosphere = No oceans in fully fluid state.** [Answer] If we are hand waving the transportation of the liquid, then the source is easy: [Tethys](https://en.wikipedia.org/wiki/Tethys_%28moon%29). Tethys' density of 980 kg/m$^3$ and spectroscopy of its surface indicates that it is almost pure water ice. And it weighs 6e20 kg, so plenty of water to go around. Assuming incompressible liquid water, it has enough payload to bury the moon under 16km of water. Even if you just slammed it into the moon, the probably has enough gravity to keep a good portion of that water. If you put it in orbit around the moon (note: do not attempt at home! gravitational effects on Earth-Moon system have not been validated!) you could break it off in chunks and throw it at the surface to liquidate the water without liquidating the moon itself. Also, there are plenty of smaller ice moons or icy comets around to supply water for you. Also also of note, if you put that much water on the moon, a lot of it will evaporate due to low pressure and solar radiation. But only up to the partial pressure of water at current surface temperature. The result will be an atmosphere on the Moon, at least for a while until everything cools down and freezes. [Answer] Reading on [Terraforming the Moon](http://www.slate.com/articles/technology/future_tense/2014/07/terraforming_the_moon_it_would_be_a_lot_like_florida.html) a while ago, it does seem to be marginally possible by repeatedly peppering the surface with comets until enough gasses had accumulated to create an atmosphere, which would then allow a liquid water hydrosphere to form. Obviously, this would not submerge the entire surface of the Moon under water (other answers have already calculated the vast amount of water required), but so long as you had accumulated enough gasses to build an atmosphere which could hold liquid ocean and allow people to walk unprotected on the surface, it seem plausible that such an atmosphere could remain for over 10,000 years. [![enter image description here](https://i.stack.imgur.com/bzfAJ.jpg)](https://i.stack.imgur.com/bzfAJ.jpg) *The low gravity means the Lunar atmosphere extends for hundreds of kilometres, resulting in spectacular cloud formations* While not long on a geological time scale, this is still twice the length of recorded history on Earth, so sufficient time to allow a civilization to grow and prosper. Of course, any really smart people who were doing this would also arrange for an artificial magnetic field and probably seal the entire Moon in a vast "bubble" of artificial diamond to keep the air in, but brute force engineering could supply the solution. [Answer] Doesn't have to be water? Great! Water is stupid anyway, boils off, totally. For a short time you get residual ice and snow, and earth has a ring system, but you don't want to sell space postcards, do you? So, to business: What you need is a liquid without vapour pressure. [Ionic liquids.](https://en.wikipedia.org/wiki/Ionic_liquid) They're cheap, you can get them at a few hundred euros per liter nowadays. And I'll give you a *real good discount* for any order of more than 200 cubic kilometres. Getting the feedstock for my lunar factories might be a bit tricky in the beginning. But I'm sure we can work something out with my friends who collect spent comets and stray asteroids to get all the necessary carbon and fluorine. I really hope your bank will be up to it. Delivery is immediately stopped when monthly advance payments are interrupted. As a plus, I guarantee without additional cost a minimal amount of foaming for at least six months. Can be extended to 12 month for a modest 25% surcharge, in advance. [Answer] Self-replicating nanobots that consume the regolith and burried ice deposits and produce nanoparticles that don’t adhere to each other, so it behaves as liquid at our scale. The hard part is providing energy. If the biofilm is on the surface of the rock and *below* the growing layer of heavy fluid, the fluid should transmit sunlight. Large particles are usually black (think petrolium) or some opaque pigment. To make it *clear* the particles are engineered to support surface phonons in the manner of plexiglas. The pool of heavy oil will Enhance the metabolism of the biofilm, protecting against damaging UV and passing the frequencies that can be used for power, blocking solar wind particles, and carying off heat. It will also serve as a medium to move different resources around as deposits of needed atoms will be found in different places. It might be designed as an *ocean* of nanotech manufacuring bots! **That’s why it was done.** Once booted up to produce a biofilm and pool filling some lowland or crater depression, you can introduce instructions to produce a larger variety of nanobots which manufacture goods of all kinds. Why let it fill the whole moon, overflowing the original basins and forming ever larger seas? Because it increases capacity and connects geologically diverse regions where different materials can be found automatically. Perhaps the civilization that produced it falls or “ascends” and leaves it to go feral. A few million years later you have something like [Code of the Lifemaker](https://en.wikipedia.org/wiki/Code_of_the_Lifemaker) but based on nanotechnology it is more indistinguishable from the kind of ecosystem we are familiar with. [Answer] You're going to need a **lot** more than current tech (it would be a huge industrial undertaking to make the factories to make the stuff to make the liquid) to 'generate' any type of liquid, even if you handwavium away the transport problem. If you merely want to move existing liquids, and you're handwaviuming from Earth to the Moon (simplest case), your only possible viable option is seawater (well, perhaps if you were willing to kill everyone on Earth by stealing their freshwater... you'd have two options) - but that won't stay liquid for long. Given enough handwavium transport, we could coat the Moon in cometary-ice, I suppose. We don't have the tech to keep any of the waters (salt or fresh) from freezing, unless we handwavium a space industry (I hope we get to transport it and all of the materials needed with handwavium, too). It might be possible to set up enough mirrors (using existing technical ideas) to heat the dark-side of the moon - but that's a *lot* of material to make and place, and to run in order to keep all of this water liquid. ie: Again with making huge industries, and probably 10s of thousands of people (maybe we could get away with just under 10k people... but I doubt it). Covering such a huge amount of the Moon's surface is going to be problematic. The lunar high point is 1938 meters higher than Everest. Granted we won't have to go that high (let's go with 8.848 km high), and surface area is 38 million km2 is **3.36224 × 10^14 m2** of liquid. That's a **substantial** number. Unless my math is wrong, all of the seawater on Earth only amounts to 1.386 x 10^12 m2, a couple of orders of magnitude less than you would need. [Answer] Oh, that's easy. Melt it. Place giant mirrors in orbit of the moon and have them reflect and concentrate the sun onto the moon's surface. You are going to want to heat it slowly and evenly. Too much heat too quickly or heat applied to locally and you'll cause vaporization and/or stress fractures. I'll add the math later tonight, but I'm sure it'll cost trillions of dollars. ]
[Question] [ In my setting, one of the habitable (?) worlds has a global average temperature of 34 degrees Celsius (93.2 F). Is this within the human habitability range, or is it too hot? [Answer] We can live in this temperature. We would have to adapt to it but we will get used to it soon. The limit for living on a planet is the point that proteins denature (~40 degrees Celsius). Because at this point we (our body) could no longer survive. [Answer] The average temperature of Earth is ~15 degrees Celsius. So, your planet is about 19 degrees warmer than Earth. I suppose Dakkar would be uninhabitable if it were 19 degrees warmer, but Helsinki would have a temperature similar to Miami. Seems livable to me, though if its life forms were autochtonous, life in each hemisphere would probably differ a lot from the other side. [Answer] A global average temperature of 34°C would be very uncomfortable and have expanses of areas uninhabitable by humans, but it would not preclude human life in some areas. The bigger problem would be understanding [wet-bulb temperature](https://en.wikipedia.org/wiki/Wet-bulb_temperature). In a civilization with advanced technology, interior areas could be made habitable, but there is a limit where it becomes impossible to survive in the unprotected environment, even if not working/moving. For that limit, the humidity of the environment influences the ability for living organisms to radiate the heat that they produce. From [this article on the impact of temperature and climate change on survivability](http://web.science.unsw.edu.au/~stevensherwood/wetbulb.html): > > The wet-bulb temperature is probably not a very good predictor of the "feels-like" temperature for most common conditions, which is why it is not used for this. However, it can be used to establish an absolute limit on metabolic heat transfer that is based on physical laws rather than the extrapolation of empirical approximations. That is why we focused on it instead of the usual measures. > > > So, more parameters are required to understand how survivable your world is to humans. [Answer] Life on Earth lives in a delicate balance. The rise of only a few degrees C would spell absolute disaster if it happened here. On Earth, the average temperature is slightly less than 15 C (58.3 F). This means that the average temperature on this planet would be roughly 50% hotter. Over the past several decades, Earth's average temperature has risen only about a degree Celsius, but that small change has had a huge impact on weather patterns, as well as the melting of glaciers, and polar ice caps. If the average global temperature is 34 C (93.2 F), then you would have to take into account that the temperature extremes would fluctuate much more than they do on Earth. A rise to 34 C would effectively wipe out most of life on Earth. Surface water would evaporate, and leave giant inland deserts. Storms would also be so massive, that we currently have no means of classifying them. It may be possible for a few pockets of life to survive, but the vast majority of the world would be a wasteland. The seas levels would also rise significantly, and low coastal areas would be completely underwater. People could survive there only in underground habitats, or possibly at the poles. The tropical regions would be completely scorched. Temperatures would exceed 70 C. The ground would be completely dry and parched. The clay would become rock hard, and there would not be any signs of life. Civilization would be incredibly insular. Since the people would not be able to travel far enough to visit other colonies. The biggest extreme would be people living at opposite poles. Their culture would evolve completely separately from each other, and they would not share a language. The people would also be adapted to the heat. In conclusion, 34 C is most likely too extreme for humans to prosper. There may be some individuals alive, but there would be a lack of resources, and especially food. It would be far more believable if the temperature was lower. Even 5 C higher on Earth would be pretty extreme. ]
[Question] [ A plot point of my novel is that the pilot accidentally finds a planet that is being purposefully hidden (i.e. been deleted from all star maps). It starts with him arriving at a location that is just empty space. Other than distant stars, there's nothing physically around him. There is a minefield of jammers though that prevent him from scanning the area so he starts searching the area and after some time, starts to see a distant planet out of the cockpit. What would be a realistic distance would the ship be in order for the pilot to physically see a planet (comparable to Earth in size, temperature and age) out of his ship? [Answer] **It's all a conspiracy.** If the planet is actively hidden (removed from maps), it stands to reason that the people in power by and large don't want this world to be found. So the reason nobody finds the planet is that approved instruments or nav software used for long range scanning and navigation are programmed to scrub certain data from the results. It wouldn't be unthinkable that the companies involved in space travel have to adhere to this, given that even today [all maps of china are wrong.](https://en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China) Or certain areas containing military bases are not even close to accurate on google maps or similar services. So your pilot would jump into a system that, according to his sophisticated sensors, is completely empty. But since the planet is only scrubbed from the sensor feeds, he can just see it through his window.[\*] [\*]: [Space is really big](https://en.wikiquote.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy) and the chances that you see a planet with your naked eye AND identify it as a planet aren't great. You need to be either very close or invest a lot of time to study its movement. So maybe he just has some after market astronomy hardware installed and uses that. So the answer to your question would be: however far you need it to be for the story. [Answer] Much of this depends on the technologies used to mask the planet, and the technologies that are being used to scan. Active jamming is not a viable plan, since it alerts everyone that something is there, and would induce people to send probes or use various electronic counter measures to see through the jamming. A sufficiently powerful active transmitter could simply "brute force" its way through the electronic interference, or the searcher can send millions of nano satellites to take a look. As an aside, active jamming cannot mask the presence of a gravitational field, so simply looking at the trajectories of the nano satellites will be very revealing. Using [metamaterials](https://www.iop.org/resources/topic/archive/metamaterials/) to actively refract electromagnetic signatures around the object being screened is far more plausible, and done properly, won't even leave a "hole" for sensors to determine that something is there. The problem is metamaterials are generally effective for a limited range of wavelengths, so attempting to screen at all possible wavelengths would require an extremely sophisticated and expensive screen. [![enter image description here](https://i.stack.imgur.com/iuFQq.png)](https://i.stack.imgur.com/iuFQq.png) *Metamaterial cloak in action* The other effect would be that the planet below would be cut off from the outside universe and end up in perpetual darkness. All life on the planet being extinguished is probably *not* the intention of whoever was hiding the planet... Gravitational effects are still not hidden by the use of metamaterials, and any infrared or other signatures from the planet may interfere with the metamaterial cloak. As well, if the planet is in communication with the outside world, then holes will need to be created in the cloak to transmit and receive, which are then vulnerable to discovery. On the other side of the equation, spacecraft will need very sensitive scanners in order to do things like detect distant spacecraft and align antenna for long range communications or weapons. In space, there is no real limit to how large you could build a receiver or mirror (a continent sized mirror of metal foil a molecule thick is theoretically possible, although rather difficult to point). Large synthetic apertures can be made by positioning elements at varying distances from the spacecraft, and having a constellation of sensor drones a light second in diameter (about the distance from the Earth to the Moon) should be no problem for a space ship designed to do scouting or exploration. [![enter image description here](https://i.stack.imgur.com/KOzhL.png)](https://i.stack.imgur.com/KOzhL.png) *Just keep adding mirrors* The fact there is a planet orbiting the star means that it would be known from the stellar survey. Currently we can detect exosolar planets even hundreds of light years away by looking for the subtle variations that the orbiting planet induces. The star and planets orbit around a "barycentre", so the size, mass and orbit of a planet can be deduced by looking for a "wobble" in the star. Arriving at teh star and *not* seeing the expected planet would be far more startling and unexpected. [![enter image description here](https://i.stack.imgur.com/QQdbY.jpg)](https://i.stack.imgur.com/QQdbY.jpg) *Finding the barycentre allows you to determine mass, orbital parameters etc.* So the idea that an astronaut could simply "look out the window" and see an unexpected planet would be pretty unlikely. [Answer] So you're interested in what the pilot can see? **Despite Earth's atmosphere**, we can still see Mercury, Venus, Mars, Jupiter, and Saturn. We've been able to do this for millenia. **More recently**, Carl Sagan asked NASA to help us take one of the [first group-selfies](https://miro.medium.com/max/672/1*6MUyun4RqF_97NKD05Hj8g.jpeg) ever. This picture was taken near Saturn's rings. Quite honestly, if they hadn't very helpfully put that arrow and text there, I would have assumed that planet Earth was a buggy pixel in Voyager's camera. Now, you're asking that a pilot might spot a random planet just by flying around a solar system a little bit. There are a few general ways to spot a planet (using some hand-waving here because fortunately we humans have always known what planet we were looking for when making our robots do our exploring). Here's a few that I can think of: **Orbital aberrations**: If this solar system is like ours, then there's a good chance that there are other planets, but this mystery planet (Planet X, if you will) is also there, just unaccounted for/hidden. If you make a supercomputer do some very hard math, you can figure out the orbit periods of each planet and look for any odd features about the ellipse with which each planet goes around its sun. Now, this means that we have to wait a minimum of 1 full orbit of the outermost planet in this system to have reliable information. Recently we have been considering the possibility of a *[Planet Nine](https://en.wikipedia.org/wiki/Planet_Nine)* in our solar system (apparently it has a mass of 10 Earths and messes with Neptune's orbit a little bit). But this has taken us this long to even notice - we've been watching the stars as long as we've had eyes, and it took us this long to maybe identify its existence. In fact, we didn't even know that any planet past Saturn existed until the last few centuries. We might assume that being able to see in space without an atmosphere to distort our vision would make it easier to spot planets by eye, but I'd disagree, because at least on Earth you know to look up. In space, you can look in every direction. All solar systems that we know of are roughly disk-shaped, so even if we know where this 'disk' is, there's a lot of space we have to look through. If we assume that our ace pilot can spot things as far out as the pale blue dot (assuming that the pilot's vision is equivalent to Voyager cameras), we're suggesting that at the nearest, our pilot can see an Earth-sized object from **6 billion km away**, and furthest, we're saying that this pilot can spot it past this solar system's sun at a crazy **12.1 billion km away** from the ship. You can make your own judgement on whether this is realistic or not. [Answer] If the planet is far from any star, you could very well rub your face on it and still not see. You already can do that in a room with lights off. It would be practically pitch black. There is simply nothing more than starlight to be reflected by its surface. And if it is black in color it will get way worse to see it. If it is very cold (near 0K), then even on IR, it would be pitch black. If you are near enough, it could be perceived as a disk oculting some stars. But you would need to be very near it, like no more than 10 times the distance from the Earth to the Moon (and probably much less). And without knowing where to search for it in the vastness of interstellar space, it would be like searching for a needle in a haystack. However, if it is as hot as Earth, it would glow in IR light. It would still be pitch black for human eyes, but some telescopes similar to WISE, but much more powerful, could perhaps see it as a faint dot from a few light years away. However, seeing and perceiving are different things. Seeing a small dot in the middle of billions of other similar and uninteresting other dots spread out randomly means that in would still be very unlikely to be noted (so, although visible, it would still be very well camoufled). It would only be noted when you are already very near to it (say, at least 20 LY, possibly much less) or if you are intensively and actively scanning each one of those dots looking for a needle in the haystack. [Answer] To reframe the question a bit... On average, the human eye has an angular resolution of ~1 arcminute (1/60th of a degree). The diameter of the Earth is ~12750 km. $$12750 / x = \tan(1') = 0.00029‬$$ $$12750 / 0.00029 = x= 43,965,517$$ So at ~44,000,000 km, an astronaut looking out the window of their spacecraft would be able to resolve the Earth as a disk and not merely as a point source of light. [Answer] Jamming sensors to hide a planet will not work, as others have explained. The better solution is to hide the planet in plain sight. There are 100 *billion* stars in our galaxy alone, and probably at least that many planets. That is so many that simply reading a list of them is impossible; you would die of old age before making a dent! So, folks search databases to find planets they want to visit. Simply change the database entry for your planet such that it isn't interesting, and nobody (except your protagonist) will ever come by and notice what you've done. I assume your story has FTL travel. What is its nature? For instance, if you have something like wormholes or hyperspace lanes, your planet is simply off the beaten path and there is no record of any resources (or a habitable atmosphere) that justifies the time and expense of getting there when so many other planets are easier to get to *and* have a reason to go there. If the wormholes or whatever are man-made, nobody has put one near this planet *because* nobody thinks it's interesting. [Answer] Move the planet. Plot device used in James H. Schmitz "The Witches of Karres" The witches periodically move the planet when the authorities get too annoyed with them. Invisible tech: So you have a planet. It has forests and lakes, and plains, and no cities. Sparse population. Posit contra-gravity (as in H. Beam Piper's works) and there are no trails/roads. Radar? What about it. Right now commercial planes have transponders so they show up decently on radar (and controllers know who's who.) A piper cub with 400 pounds of engine at the front, and the rest mostly wood and fabric doesn't give a decent radar reflection. Use paint with an impedance of 377 ohms per square, and radar energy is absorbed. Radar generally is tuned for the specific application. It's trained to disregard things that aren't interesting. Flocks of birds, planes that move at car speeds, things below 300 feet. (If you wanted to create some excitement hang a 4 foot diameter corner reflector from a drone or kite, and fly it near an airport.) So, advance the tech. Flying vehicles made with little metal and absorbing plastics. Low populations that can live on agroforestry. ]
[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/78308/edit). Closed 6 years ago. [Improve this question](/posts/78308/edit) People are afraid of (probably) everything you can think (animals, open spaces, closed spaces, death, and so on). Of course that not everyone is afraid of everything, but generally it is. But is there something what can be god(s) afraid of? And how strong the fear may be? --- Most of gods are (probably) afraid of losing of worshippers - because amount of worshippers limits their power and life. But what if amount of worshippers does not limit their power and life. What they (gods, of course) can be afraid of then (else)? --- **Example:** Currently (for some time) they are afraid of power of Icefingers the Bloodhand, because he handles magic in such way that it can destroy the world (and kill also gods). Only saying of Icefinger's name causes panic fear in gods ... but still they are eager to see what shall happen, so they pass that fear. [Answer] The answer is anything you please. It's your world, and gods typically have the power to be... well.. anything you want them to be. Typically we give them fears that us mortals have, so that they resonate with us more. If you want to have some fun, though, you can break out the [Lövheim cube of emotion](https://en.wikipedia.org/wiki/L%C3%B6vheim_cube_of_emotion) [![Cube of Emotion](https://i.stack.imgur.com/K4P5v.png)](https://i.stack.imgur.com/K4P5v.png) The cube of emotion is a recent model which theorizes that there is a connection between our emotions and the three monoamine neurotransmitters. While still an early model that needs to be defended more, it is the first to truly tie emotions to chemicals. As such, it permits us to use neurochemistry to explore new sides of emotion. Fear appears in the bottom left corner. It's where you have high dopamine but low noradrenaline and low serotonin. Now your gods might not have neurotransmitters, but we can look at their behavior and see if those neurotransmitters might give you some ideas. What follows is a gross oversimplification of how our brain works, but it's interesting enough for me: * Noradrenaline is associated with unpredictability in the environment. If we're having trouble with predicting the environment, noradrenaline will spike. In fear, its low, so we're pretty sure the environment isn't actually changing all that unpredictably. * Seratonin is associated with how happy the body is. When you eat food, seratonin goes up to let you know you did a good job. It's the link to your lizard brain. If seratonin goes low, that means your lower brain is pretty certain that things are bad. * Dopamine is associated with reward seeking behavior. High dopamine means you think there are rewards to be had (or in the case of fear, you think there might be a way out, you just have to find it) So when you put these together, you see that in fear, your more base self is quite certain things are bad, and you're not seeing them changing, and you're pretty sure you need to seek a way out. Let's put this against an example. Arachnophobia. First, an inspirational photograph: > > [![Spider](https://i.stack.imgur.com/TqHQT.jpg)](https://i.stack.imgur.com/TqHQT.jpg) > > > Something deep rooted in your lizard brain has taught you that this pattern of legs and eyes is bad. Really bad. Bad bad bad bad news. It lets you know "you are failing at life right now. This is not how it is supposed to be." Worse, things aren't changing. Your husband isn't coming by to whisk the spider away. In fact, the soon-to-be-about-to-sleep-on-the-couch-for-a-week fool is laughing at you. (In his defense, it is a cute little jumping spider!). Your body checks the scene again... yep, it's not changing. There is nothing to make this spider go away for you. But you know there's a solution. Somewhere in this god forsaken spider-infested world, you know that you can make it better. Of course, you have to get past the nerves first. Perhaps a haiku will do. I composed my wife a haiku for such a moment a while back. I called it "Spider," and it went something like this: > > Spider: splat splat splat splat, > > splat splat splat splat splat splat splat, > > splat splat splat splat splat!\* > > > I think I captured the art of the hakiu pretty solidly in that one. It was missing a cutting word, though. Mostly spatting-words. Oh well. So if you take those three attributes of fear, an unhappy base self, lack of change in the environment regarding that unhappiness, and the idea that you might be able to do something about it, you have a pretty generalized sense of what one might be fearful of. If your god has some underlying essense that can be happy, you're on the road towards the god being able to have a fear. May I suggest your god have a fear of spiders? Just sayin' \* *The original poem ended with the line "splat splat splat, all gone!" but my wife was insistent that wasting two syllables worth of splats was not worth it, just in case the spider might have pulled through, so the poem is shown here in its more refined form.* [Answer] ## 1. Other gods If by gods you mean entities similar to the ancient pagan gods, then remember that said gods represent **parts** of nature and the universe (for example, lightning and fire, skies and sea, war and love, harvests and death). This means that gods may fear other gods. You may then enter in a Pokémon type game, whereby gods of a certain type fear gods of a type that is supereffective against them. --- ## 2. Fate But, if ancient pagan gods represent just a **part** of the universe, this means that they can't account for The Overarching Principle that governs the **entire** cosmos. On ancient pagan religions, said Overarching Prínciple was an impersonal and irresistible force that drove every being (including the gods) to their fate. Not surprisingly, that Overarching Principle was called Fate. So gods fear Fate. Or any other Overarching and Irresistible and Impersonal Principle that ultimately rules the functioning of all the cosmos. Not conforming to the place in cosmos to which Fate has placed you is called hybris, and gods could be guilty of it. Ironically hybris would only lead to their demise, even at the hands of mortals. --- ## 3. Chaos Finally, on ancient pagan religions, gods are **not** the primordial beings that created the universe. Rather, the present cosmos is nothing more that Order that came out of Primordial Chaos. That Order is symbolized by Fate, but Chaos is always seeking to reintroduce itself on the cosmos that it lost. Since gods derive their power from Order, they fear the resurgence of Chaos. Bear in mind than on pagan religions, Chaos is as much of an Impersonal Overarching Principle as the Fates... only a Principle that was defeated on the beggining and can come back at any time. Regarding Chaos, that is interestingly the real reason why gods fear the loss of worshippers. If mortals do not submit to the gods, they are rebelling against the established Order, thereby opening the gates for the forces of Chaos to enter the cosmos. On the best case scenario, Chaos would destroy the World and the gods would not have nothing to rule over. On the worst case scenario, every single being would perish... including the gods. --- [Answer] Are we talking about an omnipotent God? In that case, I'm not sure there's anything you can do. But if you're talking about a world where gods don't have absolute power, then the answer is simple: anything outside their realm. Take ancient Greece as an example. Zeus had control over the sky, lightning, etc. But he wasn't in control of the seas - that was Poseidon's turf. Zeus and Poseidon classically had a big sibling rivalry in the Greek myths. And for good reason. Let's say that the other eleven Olympians were sick and tired of Zeus hogging the throne for himself. If they ganged up on him, they could very easily defeat him, assuming it's them against him with no backup on either side. Or perhaps you'd like a world like that of the Percy Jackson books. As the series progresses, Riordan makes it very clear - even developing it into a *very* central plot line in his new series about Apollo - that the gods remain immortal so long as they have worshippers. If they are no longer worshipped, they die. Conversely, one can make himself into a god by gaining worshippers that continue to deify him or her over the millennia. In this type of world, having believers could be a huge worry. After all, your life literally hangs on whether people worship you. Or worse: people could invent a new god who's even more powerful than you are. [Answer] "Fear" entails a change of circumstance. No-one fears the past; it has come and gone. The present is not feared either although one might be afraid in the present because unfolding events imply a change of circumstances for the worse. I might be afraid of a snake in the present, but underlying that fear is my concern that the snake will bite me. I might be afraid of the great height I am teetering on, but underlying that fear is my concern that I will fall. Some fear is rational and some is not. "Phobias" are a category for which the fear is inappropriate for the actual possible future circumstances, to the point where the fear interferes with the individual. I may fear snakes so much that I decline to go anyplace one might be. Now gods. You can define them as you like. Maybe they need worshippers and maybe they do not. The Cthulhu mythos gods might have worshippers but they do not need them. Maybe they can be killed and maybe not. I can imagine though that even aliens gods such as these have one set off circumstances they prefer over another. Cthulhu might prefer to be cruising around rather than trapped sleeping in a sunken city. So: 2 things for you to make up. One is the nature of your gods and the circumstances they prefer and dislike. Two is the rationality of your gods: you can state that one fears a given thing but there need to be no obvious connection with that thing and the possible future situation unfavorable to that god. If your gods are characters there might be narrative possibility in unpacking exactly what that connection is and how the god came to understand it - sort of like unpacking exactly how Indiana Jones came to fear snakes. [Answer] Looking at stories I’m familiar with, I recall several trends: ## their peers A more senior god may order them around, forcefully transmogrify them, imprision, banish, or kill them, etc. More equal gods or juniors may turn the tables and hurt the more senior boss god. Or, just being a gossip and busybody makes the high god “afraid” of them listening in and/or meddling, as this disrupts his plans even if it doesn’t hurt him per se. ## their children Both full next-generation gods and demigods are *always* causing problems. ## their parents Likewise, gods might eat their full-god children ## special artifacts A special totem, sword, cup, or other object may give the bearer power over the god, or banish or kill the god. ## knowledge Likewise, mortals, demigods, other gods, or other magical beings might **learn** of a secret weakness or the recipe for magic that can do whatever, as with the artifact case. ## time All things run out, even the Universe runs down. --- The cases that come to mind include: * Greek and Roman Mythology (the story book I used in 6th grade was a paperback in modern English based on [Bulfinch](https://en.wikipedia.org/wiki/Bulfinch%27s_Mythology) if I recall correctly). * [Season 5 of *Buffy the Vampire Slayer*](https://en.wikipedia.org/wiki/Buffy_the_Vampire_Slayer_(season_5)). * *The Magicians* ([T.V. series based on Lev Grossman’s book](https://en.wikipedia.org/wiki/The_Magicians_(U.S._TV_series))). For gods **in which the idea applies** (powerful class of beings that exist *within* the universe), it’s no different than science-fiction beings of great power, including those *pretending* to be gods such as with the *Stargate* franchise and a few episodes of Star Trek. --- # Omnicient beings For a kind of supreme being that exists *outside* of the universe, that has complete knowledge of all of space-time, and is not affected by anything in the universe, then the concept does not apply. But, consider the case of a human who makes a movie. You have complete knowledge over the events; you can examine each frame and run it backwards and forwards and watch a scene again and again. Nothing happening in the movie can reach out and cause things in your “outside” reality. But, people are still “scared” of [*Psycho*](https://en.wikipedia.org/wiki/Psycho_(1960_film)), and can be affected psycologically by the knowledge of the work. In his own reality, the producer and director have lives with concerns and fears. They are not scared that some event or character in the movie will hurt them, but might be worried about box-office performance, lawyers, taxes, competitors, and other issues *caused by* the work existing and the specific content of it. [Answer] * Eh, going to go with the classic: things that are fated to hurt them or are immune to their power. * OR things to go with their powerset. So, every god has a skill set and thing--so a god of the woods might be afraid of fire--after all, that god may have the memory of a thousand trees dying via fire. This god might also not be fond of axes. Gods can be just as neurotic and fearful as people, if you want them to be. It's your playground. They can be afraid of literally ANYTHING if it makes sense within the framework of their abilities. [Answer] Sufficiently powerful mortals... See: [Odysseus](https://en.wikipedia.org/wiki/Odysseus) [Heracles](https://en.wikipedia.org/wiki/Heracles) [Friedrich Nietzsche](https://en.wikipedia.org/wiki/Friedrich_Nietzsche) [Richard Dawkins](https://en.wikipedia.org/wiki/Richard_Dawkins) Some actively fought the gods, and some fought the premise of "god/s" both were pretty effective. [Answer] Gods can fear their own creations becoming too powerful. For example, [Genesis 11:3-7](https://en.wikisource.org/wiki/Bible_(King_James)/Genesis#11:3) aka the [Tower Of Babel](https://en.wikipedia.org/wiki/Tower_of_Babel). > > 3 And they said, “Come, let us build ourselves a city, and a tower whose top is in the heavens; let us make a name for ourselves, lest we be scattered abroad over the face of the whole earth.” > > > 4 But the Lord came down to see the city and the tower which the sons of men had built. > > > 5 And the Lord said, ***“Indeed the people are one and they all have one language, and this is what they begin to do; now nothing that they propose to do will be withheld from them.*** > > > 6 Come, let Us go down and there confuse their language, that they may not understand one another’s speech.” > > > 7 So the Lord scattered them abroad from there over the face of all the earth, and they ceased building the city. > > > This is usually interpreted as punishment for humanity's hubris, but it can also be interpreted as God fearing humanity's potential power if they continue to work together. This is not meant to spark a Biblical debate about its interpretation, but to give story ideas. [Answer] What scares us? Beyond phobias, anything that can hurt us. Same should apply to gods. Now what can hurt a god very much depends on your world. What gives your gods their power? If worshipping is their source of power, does losing that mean death or eternal slumber? The former would be scarier but the latter would mean some form of imprisonment. Perhaps you gods have great power but aren't indestructable. Then any skilled mortal may cause them fear. A great warrior might can them great pain, mutilate them even. If older primordeal beings exist, those may be more powerful. Those could be feared. That depends on why they're no longer here. Are they sleeping? Fear of waking them up might be a very real thing for those gods. In a similar vein perhaps there powers beyond the gods. Maybe there is an underworld or afterlife for them. Perhaps they fear one day to be trapped there. Perhaps it's a force of nature, completely beyond their control. Maybe the gods are programmers. Perhaps what they should really fear is their software. If it ever finds a way out of the simulation it might wreck the world. Maybe it's an AI fearing a fatal loss of power. It really depends on the limits you've imposed on your gods. The Norse gods 'feared' Ragnarok as it will bring the end of the world and their death. [Answer] Actual examples of actual gods being actually afraid: * The One God (who speaks of themselves in the plural) of Hebrews and Christians: > > "And the Lord God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever: Therefore the Lord God sent him forth from the garden of Eden, to till the ground from whence he was taken." (Genesis 3:22-23) > > > "And the Lord said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do. Go to, let us go down, and there confound their language, that they may not understand one another's speech." (Genesis 11:6-7) > > > * [Cronus](https://en.wikipedia.org/wiki/Cronus), the supreme 2nd generation god in the Greek mythology, learned from his mother Gaia "that that he was destined to be overcome by his own sons", so he decided to eat his own children. (Summary by Wikipedia.) It didn't help, he was eventually deposed by Zeus and imprisoned for ever in the prison of Night. * [Zeus](https://en.wikipedia.org/wiki/Zeus), the supreme 3rd generation god in the Greek mythology: > > "Zeus had received a prophecy that [Thetis](https://en.wikipedia.org/wiki/Thetis)'s son would become greater than his father, like Zeus had dethroned his father to led the succeeding pantheon. In order to ensure a mortal father for her eventual offspring, Zeus and his brother Poseidon made arrangements for her to marry a human, Peleus, son of Aeacus." (Summary by Wikipedia.) > > > Even that most manly heroic Odin sometimes expresses fear of the unknown: > > "Hugin and Munin fly each day over the spacious earth. I fear for Hugin, that he come not back, yet more anxious am I for Munin." (From the [*Poetic Edda*](https://en.wikipedia.org/wiki/Poetic_Edda), translation by Benjamin Thorpe, from the Wikipedia article on the ravens [Huginn and Muninn](https://en.wikipedia.org/wiki/Huginn_and_Muninn)) > > > [Answer] First you should be aware of the fact about FEAR. Means why exactly we feel fear? The root cause of fear is "`Desire'". Desire might be the only thing that causes fear. For example have a look at following... * If you have Desire of Win then you will be afraid of loosing * If you have Desire of living then you will be afraid of death * If you have Desire of profit then you will be afraid lose. * If you have Desire of Respect from other then you will be afraid of Disrespect (and that eventually cause obstacle in you duty) and so on... So if people have Desire of anything then he/she must have fear of not fulfilling that Desire. As per the Holy Book of Hindu (Bhagwat Geeta) stated that If a person can control his Desire then he can get fully control on his/her fear. By following this teaching many saint use to leave all his Desires and start living ordinary life with only limited resources. Hence the most fearless human in the world is those saint who left all their wishes or Desires and got fearless. **Now let's talk about How much fear/desire God has** As per Hinduism (don't know about other) We have two division of Gods. One called `Bhagwan` and other called `Daiv`. Don't know what is the English meaning of them but you may consider `Bhagwan` as Lord and `Daiv` as God. Bhagwan (Lord) is the one who created this world and other creatures (including Daiv/God). Bhagwan (Lord) not only created world and living things but he also created feelings (like anger, fear, whish ect) and impose all on us. Means what ever we feel because Bhagwan (Lord) wish us to feel. Lord himself dosn't come under all these feeling but we all comes. But Lord also told us about how to overcome those negative feelings (anger, fear etc) via his Holy books. One short example of fear I have shown in beginning lines but in Holy book of Hinduism, it is written in brief that how we can get rid of all weaknesses of humans and can be like Lord himself. [Answer] God, as omnipotent and omniscient being, doesn't have to fear anything. It means more, as he(she,it) simply doesn't fear. It means, the terminology, "God fears" or "God doesn't fear" don't have sense, or if it has, it is over the level, what we could understand. --- The situation is a little bit different in the case of polytheist religion systems, including the fantasy & RPG-invented ones. These gods aren't omnipotent or omniscient, they are simple mortals, with their limits. They aren't gods in the sense as we can read it in the Bible. The only difference to us that these limits are in their case much wider (different, typically strong magical power, biological immortality, etc). In their case, they can fear anything which greatly reduces these limits, their goals or their future. For example, an AD&D demigod, whose only way to die is being killed by a Magical Axe Artifact, can fear any hero nearing him with this artifact. [Answer] What's a mob to a king? What's a king to a god? What's a god to a non believer, who don't believe in anything? --- But honestly, their ultimate "fear" would be a lack of purpose. This would come in the form of becoming irrelevant. Possible roads to reach this state of null would come through being replaced, ie: young gods, or forgotten, ie: non-believers. [Answer] Actually there are two categories of fear: * Phobias, which are fears that are not rationally justified. You can give your gods phobias about anything you want. They may even rationalize that there is no danger from it, but they still are afraid of it, because fear is irrational. * Rational fears. I'll concentrate on those below. Now when excluding phobias, what do you need for fear? * It must be something you care about, and would not want happening. I don't fear that a sack of rice falls over in China, not because it is impossible that this happens, but because I don't care if it happens. Note that the object of your fear need not be connected to physical harming yourself. For example, a mother fearing for her child can be personally perfectly safe. Also, I don't fear good weather, not because I wouldn't care about it, but because I actually like good weather. * It must be something that (you believe) can possibly happen. I don't fear that I'll be abducted by aliens, not because I wouldn't care if I were, nor would I like it if it happened, but because I don't expect it to happen. * It must be something you don't (feel you) have control over. Something you can prevent, you don't have to fear (if you do anyway, either it's lack of confidence, or a phobia). I don't fear to starve, not because I wouldn't care, not because I'd like to, not because I consider it impossible, but simply because I believe I've got the means to prevent it. The first bullet is easy to fulfil: Every god will have something he cares about. Maybe the god of the oceans fears pollution of the oceans, not because it would harm him, but because he likes the oceans, and certainly wouldn't enjoy them polluted. The second and third bullet require that your gods are not omnipotent. However the important limitation can well be just the other gods, if the gods are at odds to each other. Of course if you want *existential* fear, then you indeed must make the gods not entirely immortal; Icefinger's magic from your description is just that. But remember that not all fear is existential. For example, the fear of social decline is rarely existential (unless you're very close to the bottom, your life is not in danger from it), but nevertheless can be very real (and if your gods have a social structure of their own, they can indeed also have that fear; your mentioned loss of worshippers might play a role in this as social status among the gods is likely correlated to the number of worshippers, but there might be other issues, for example the favour or disfavour of higher-up gods will likely play a role for the lower gods). ]
[Question] [ **This question already has answers here**: [What are the enabling factors for melee combat in modern or future settings?](/questions/3358/what-are-the-enabling-factors-for-melee-combat-in-modern-or-future-settings) (17 answers) Closed 7 years ago. Let's be honest, swords are cool, we can all agree on this, but the invention of the bullet (which removed the musket's reloading time) has practically removed swords from any form of combat where guns are an option. What can I do to make sure that soldiers in my culture still use swords with their guns? What changes must I make to history? Is it even possible to achieve this? Unlike [this question](https://worldbuilding.stackexchange.com/questions/3358/what-are-the-enabling-factors-for-melee-combat-in-modern-or-future-settings) I am specifically asking for swords in modern scenarios,as opposed to general melee in the future. [Answer] I'm going preface this by saying that anything I don't back up with a source, I've learned by my experience and study as a Historic European Martial Artist (a HEMA practitioner, for the acronym minded). This answer has some background before actually proposing solutions, but that background helps to understand what you need to change. # The Modern Case for Swords There are actually modern situations where a sword would do much better than a gun. The police have a "[21](https://youtu.be/K1HbEUPfjqM) [foot rule.](https://youtu.be/J_KJ1R2PCMM)" Basically, a person with a knife (or sword) wins against a person trying to draw a gun. Even with a gun drawn, 10 feet beats a gun. Body armor for bullets does not mean body armor against knives or blades, [as seen here](https://youtu.be/Dxi2NDwbsQ8?t=30s). In fact, some companies which attempt to provide prisons guards armor need to change their armor to adapt to stabs. (As you can see [here](http://www.warwickmills.com/Body-Armor/Corrections-Officer-Protection.aspx), this armor is specifically meant for protection against stabs, not bullets! They also sell different armor for ballistic protection because they're not the same thing!) Additionally, it's been known for a long time that you aim for [the weak](http://67.media.tumblr.com/3495d6e0d0772223a339d90016774d67/tumblr_inline_o0yyh5ete91s71ybj_500.jpg) [spots](https://66.media.tumblr.com/c48f4d0d4747c030ac955274915d3572/tumblr_inline_o0yygs7PrQ1s71ybj_500.jpg), so don't stab/shoot someone in the gut when you can go for the unprotected face! That makes this whole armor argument a much more tricky! So swords in warfare? This isn't something we've seen for a long time, mostly because it's hard to get a large force within 21 feet of solders. As seen in this [reddit post](https://www.reddit.com/r/NoStupidQuestions/comments/2z3mvk/are_swords_still_used_in_modern_combat/), where veterans and solders talk about it, bayonets and some knives still see use in modern warfare. These blades are usually used in urban areas, where you may not have time to aim your gun. Can a sword do a little better than a bayonet or knife? Well yes; you will (generally) have increased reach, so you can kill the other guy before he reaches you. Additionally, swords can have more cutting (or thrusting) power than a knife, and can also be used in [grappling](https://youtu.be/T5aE7a53S0w). Actually, this is a general trend in combat in general; if a weapon allows you to kill them before they can even reach you, or allows you to fight at the same distance, you use that weapon first! (Tactical considerations aside...) I'm calling this the "kill them at distance" (KTAD) principle. # Why No Swords Today? Coming from a Historic European Martial Arts background, I know that swords were more commonly sidearms than primary weapons. **The weapon of war before the rifle was, generally, a staff weapon.** (Staff weapons include spears, lances, and other pole-arms.) This is because of the KTAD principle. Pike formations were even common into the [late renaissance](https://youtu.be/PbhANeJL_T4), where muskets were common. The bayonet became popular because you can get some advantages of staff weapons but also retain your ability for long-distance combat. (Although [some people](https://youtu.be/hKRa966S5Dc) say bayonets may not actually have seen much killing...) During the colonial age, many solders used swords as a backup weapon because they were often outnumbered and their gun was not up to the task of killing that many people before they were overrun. In any case, as guns became easier to use and their rate of fire and capacity for armor penetration increased, people took the KTAD principle and selected to use the weapon that kills the enemy without putting themselves in mortal danger. Early in the days of muskets, people did still wear plate, and it did help against musket fire. Eventually, though, the power of the bullets were simply too much for the armor of the time, so the increased weight of the armor was a liability and therefore ditched. # How Do We Bring Swords Back? * Make gun operation more expensive. Some component of the gun, ammunition for the gun, or even raw materials for the gun may be too rare for guns to be widely adopted, such as [cannons or guns](https://youtu.be/fV-uC7ubrIo) in the Middle Ages of Europe. * Fail to develop good methods of gunpowder manufacture. * Make really good anti-ballistic armor. This is the case in [DUNE](https://en.wikipedia.org/wiki/Dune_(novel)) series. * Have battles take place in confined areas or areas of poor visibility, which requires the fast reaction time for combat. * Have strong cultural preference for carrying swords, such as the case of the [Gunto](https://en.wikipedia.org/wiki/Gunt%C5%8D) (Japanese WW2 swords) or [British Officers during the colonial era](http://www.skminiatures.co.uk/communities/7/004/006/892/707/images/4525439432_pre.jpg). * Develop a strong cultural preference for handguns. When the gun jams, or when the solder cannot reload, they switch to their side-swords. (This does set up your culture for an extreme shift in thinking about combat, such as that [Shaka's shortspear](https://youtu.be/BZLGKFWlRzY?t=2m34s) did for the Zulu.) * Fail to develop timing mechanisms, which then prevents machine guns from developing. [Answer] You need lightweight, full-body armor that's resistant to high-kinetic-energy projectiles, aka bullets, but vulnerable to slicing (the shields in Dune, but without the handwaving). Although I suspect the first thing militaries would do to counter the armor is invest in a lot more artillery, not spend hundreds of hours training grunts to use swords... [Answer] ### Legal legacy What if duels were legal, but only with swords? If you kill the opponent on a proper duel you face no reprecussions. Of course, trained person would easily defeat untrained person. If nobility was consistently trained then they would like how things are.The law is just, it allows self-defence for poor and rich alike. When guns are introduced, duels with guns would be outlawed (because power balance shifts in a way elites don't like). Guns could be also outlawed for self-defence too. Then people will carry swords instead of guns: sword is a pretty convenient melee weapon to carry. Of course, on the battlefield soldiers *will* carry guns if those are effective. What can be done about that? Well, if everything happens in space then soldiers don't need to carry guns - stuff like boarding is heavily unlikely and they won't ever get to a personal gun's shooting range. Navy people could easily carry swords though. Carrying a gun is pretty stupid in space - there's only your crewmates to shoot and if you miss both your target, you and people in immediate vicinity are going to have a bad time. [Answer] Heavy armor or shields, that are reactive to fast moving objects or objects with high energy can be countered by close range combat weapons like swords. This method is probably most commonly seen in games like [Mass Effect](http://masseffect.wikia.com/wiki/Kinetic_barrier) but there are also mentions in Frank Herbert's Dune in the form of [shield belts](http://dune.wikia.com/wiki/Shield). **Shields:** A simple way to realize such shields on todays technological basis would be some kind of electromagnetic shield (EM-shield). There is the concept of [Eddy current brakes](https://en.wikipedia.org/wiki/Eddy_current_brake) which use magnetic induction within conductive materials to transform kinect into heat energy. This concept is based on inhomogeneous magnetic fields. A fast moving object has to travel through this field and as an effect of the changing magnetic flow (due to the inhomogeneity) will then generate currents according to [Lenz's law](https://en.wikipedia.org/wiki/Lenz%27s_law) that counteract the change in magnetic flow. Those currents will (due to the electrical resistance) generate heat and reduce on basis of the conservation of energy the kinect energy of the moving object. A neat coincidence is that faster moving objects will have higher rates of kinect energy loss and thus experience the biggest "repulsion". [This short video](https://www.youtube.com/watch?v=N7tIi71-AjA) shows the concept, however here, the magnet is moving which in general can be interchanged by a stationary magnet and a moving conductive material. With high enough field-strength, in principle every material can become conductive. There is also the possibilibty of incorporating fast changing electric fields. A static field can split up charges within an object and thus create measurable postive or negative charges on opposing sites. These in return can be used to repulse the object, however a change in the direction of the electric field has to be employed to do so. The object will react to the changed electric field polarity within a small time interval in which the electric field has to be changed again. This, however, needs active recognition of the object's material e.g. on basis of the induced fields to modulate the shield accordingly. A general drawback of a repulsive shield system is that in general all systems have to obey to the conservation of momentum. That is, the shield systems will always generate a momentum, depending on the relative mass between the moving object and the shield system (e.g. light objects can be stoped more easily as heavy ones). This however, is another argument for fighting with swords instead of bullets. **Armor:** There are materials that react to fast moving objects differently than to slow ones. Take for instance [non-newtonian fluids](https://www.youtube.com/watch?v=2mYHGn_Pd5M), that become much "harder" on impact of fast objects. Such materials could be used as armor layers to protect against fast moving objects while letting slow ones still pass. This has the advantage that slow movments (like body movements) will not trigger the protective effect and thus will not harm the wearer's mobility. However, the speed of a striking sword is in the range of usual body movements, making this type of armor less effective against swords. There is also a material called [Starlite](https://en.wikipedia.org/wiki/Starlite) (however, its inventor didn't publish its composition) which is told to be resistant against laser beams due to its great insulating capability: [click for video](https://www.youtube.com/watch?v=RxqFyDugqs4) [Answer] Swords fell out of use largely because they became more and more useless in war and culture was became more and more urban thus less and less people had use of it in their day to day lives. With the advent of guns this just sped up their demise as the weapon of choice in areas of life... So how do you bring swords back in modern days? * Make the materials to make guns or gunpowder harder to come by thus reducing the amount of use you can have for them. * Make an armor that resists guns shots, but is not resistent to cutting. This might come about through metamaterials, but in sci-fi there are personal forcefields that protect against kinetic weapons but let everything else pass through. * Currently soldiers carry about 50lbs. Make a new piece of essential equipment that makes carrying amunition or a gun near or totally impossible and you'll start to see people carrying swords instead of guns. * Make Long range stealth technology cheap that until someone is close they can't be seen and again people will start using melee weapons rather than guns. * If you're ok with slightly futuristic and moving to any sort of pressurized area that military will fight in such as space ships or pressurized domes used to colonize planets then they are going to use mostly melee weapons because you can't risk putting holes in such structures. So there is plenty of ways to possibly move back to swords, but you also then have to make sure it's not viable to use steel armor either cuz then swords are worthless again. [Answer] Swords were used until the end of the 19th century, one thing changed the deal in warfare, the [Haber process](https://en.wikipedia.org/wiki/Haber_process). It's a chemical process that synthesize ammoniac the rarest component of explosif at the time. With this process we extract ammoniac from the air, before it was a natural formation collect in moist caves. It maid explosive incredibly cheap and the production of ammunition exploded. This lead to the artillery based strategy of the WW1. Without this process you cannot maintain a long conflict based on gun power, it will still be there and most of the kill will be by guns but you will have some cool actions with blades. An another point on why they stop using swords is it need more training than guns : The Haber Process was also a true revolution in agriculture since ammoniac is a used in fertilizer. Without it humanity would not have been able to grow has much and the demography would be very less high. This give you less people to do war. The point is with less soldiers you can't just throw untrained young people into the hell of war. You are more incline to train well your troops => give them a sword trainning. [Answer] Guns shoot bullets according to a maximum rate of fire. The faster that rate of fire becomes, the shorter the distance becomes between bullets. The fastest rate of fire there can be is one in which there is **no** space between bullets—i.e., the bullets are touching each other end-to-end as they exit the barrel. So now the weapon looks feels different. Instead of firing a series of projectiles, it is essentially a solid cylinder of bullets pressed together end-to-end. This is like a sword with a long, spaghetti noodle for a blade that is actually bullets moving incredibly fast and tearing through whatever the operator waves the gun at. You don't need to aim by pointing and shooting, but rather just a slice that causes the bullet string to sweep across the target, like a blade would. **Update in response to comments:** A machine like the sword-gun would consume an enormous amount of ammunition that its operation is somewhat prohibitive, but not impossible. It is not the kind of weapon that one soldier can carry into battle as a personal weapon, but rather it's like a stationary piece of artillery that is connected directly to the outlet of a supply column that serves it. Several guns stationed at artillery bases would allow operators of the device to slice through the gates of the city while laying siege from miles away. As many as hundreds of miles behind the front lines there are mobilized bullet factories operating at peak capacity to pump a continuous stream fresh bullets into bullet pipelines. These large pipes run over the surface of conquered lands directly to the front lines and into the sword-guns. Use of the sword-gun has environmental concerns as well. After a city has been ravaged by these weapons there is an enormous amount of bullet metal buried deep within the scars of the city. It could take many months to mine out all of that material when the city is reconstructed after the battle. ]
[Question] [ In [how smart can I make ants](https://worldbuilding.stackexchange.com/questions/45037/how-smart-can-i-make-ants), an idea was suggested, to instead of making each ant individually sapient, [make the 'anthill' as a whole sapient](https://worldbuilding.stackexchange.com/a/45046/885); a kind of unconventional hive mind. Just as a familiar anthill is more like a single body whose organs happen to not be stuck together, my alien intelligence develops on the level of a colony. Just as a single brain cell is not a mind, a single bug is not sapient. To quote the accepted answer: > > It is the level of a colony that has a single DNA and evolves as an > animal. Individual workers are no different than our individual cells > which are replaced from within as they wear out. The colony has intent > and direction and will decide when to move or camp, flee or fight, > discover new food resources and hold social relations with other > colonies. The individual bugs communicate via hormones etc. just as > the cells and organs within a body coordinate, but are one system. > > > In summary, the basic concept here is that hundreds of thousands (if not millions), of small creature are able to make up one big creature, in the same way cells make up humans. Ever since hearing this answer, I have become obsessed with this idea but I, as a hard-science fiction worldbuilder, must know if this concept is at all realistic. So, is this concept of a collective consciousness realistic? And if so, how would it develop from regular ants? [Answer] Hmm, this started out as a comment but got better. Perhaps the colony did not develop intelligence as a first step, but became something more, first. Look at the analogous question: how did a [biofilm](https://en.wikipedia.org/wiki/Biofilm) of [eucaryote cells](https://en.wikipedia.org/wiki/Eukaryote) stuck together become sentient? Well, not directly as one thing. Multicellular life developed, with *increased specialization* of different cell types and tissue forming *encapsulated organs*. One organ *specialized in information processing*, developing from tissue whose role is to distribute and process signals. So, a mass of ants is like a biofilm. Increased specialization with different types of ants and coherent groups applied to specialized purpose is like development of a higher level of life. We see that beginning with ants and termites already. Information and coordination works via phermones and shared stomach contents between workers, with no central controller. This is like cells coordinating via hormones. **Add a new caste**, a ***courier***, specializing in sending messages directly to distant reaches rather than diffusing slowly through the population. These can relay messages from one *organ* to another, directly and quickly. Say, fungus farmers deep in the mound can prepare for the load found by the foragers, because the collective mass of workers foraging give summaries to a small number of express couriers which make rounds back and forth. Couriers are nerve tissue. Now what happens if the population of couriers in a chamber, waiting their turn at a courier run, just mulling around eating and resting, communicate the diffuse way as all ants do? It might start to develop a mass of connected nerve tissue devoted to being interconnected among its own mass of cells. See where I'm heading here? --- And don't forget to read [GEB](https://en.wikipedia.org/wiki/G%C3%B6del,_Escher,_Bach)! [Answer] In a small way this happens already. Weaver ants have a very complicated communication system using pheromones that allows for an unusual amount of cooperation. A lot of that is hard wired into the ant as instinct; When I smell this, I do this. If the smell is stronger over here then that's where I should go. The trick would be a very small evolutionary change that gets rid of the hard wiring and allows for a bit more flexibility. This could allow for inspiration to do something more than "make a nest, look for food." The other important part would be a way to have a collective memory. If each ant is just doing its part and responding to what's happening right now, it would be a like a person with [anterograde amnesia](https://en.wikipedia.org/wiki/Anterograde_amnesia), which would wreck any hopes of them developing sentience. This could be accomplished with chemicals; maybe each ant laying down a pattern of pheromones into the walls of the nest of the signals and messages passing around the nest, or it could be a special class of ant that does it. Perhaps while taking care of the eggs and larva. By having memory and history, you can see where you're coming from and where you're going. Eventually it might develop into what could be seen as a biological computer, with input from the scouts, short term chemical memory in the form of scent trails (RAM), long term chemical memory laid down in the walls of the nest (hard drive), and the collective processing power of several million ants. [Answer] **Yes, but...or No, but** ...its weird I just realized those mean virtually the same thing... So there are questions that need answering. Primarily who are your **actors**. What use is sapience to your ant colony? If they are, as a colony, creating sapience. * Who/What is the receiver of the little pieces of information from the individual ants? * Who/What is using the information being collected? * How is the collected information being used? Additionally you need a **transfer medium** for your information. I would suggest some form of electro-chemical transmission, ants already use chemical trails to mark paths and others to announce intruders...but those aren't real precise...sapience is going to require more precision. In nature, **energy efficiency is paramount**. The more complicated the creature the less energy efficient it becomes. Complex organs and systems require far more upkeep and energy. They just happen to offset the energy requirement by increasing the creature's survivability. **Size** is an issue here...any organ(s) is going to require energy to maintain it and keep it functioning...can an ant maintain the level of energy required to support such a communication method? So. To wrap up you need to. * Define your communication method and how it will work. What kind of energy requirements does it have * Define collecting agent for your information * Define the acting agent, who/what is sapient and making decisions * Can the size of your creature support the energy demands of such a specialized organ? In short: **Sapience requires specialized members of the whole to transfer and process information.** So I am pretty sure you at least need one of these. (and I am not talking about NPH but that probably wouldn't hurt either) [![enter image description here](https://i.stack.imgur.com/fXelC.jpg)](https://i.stack.imgur.com/fXelC.jpg) [Answer] Well, you need a means of communication, and a way of powering it, both of which may be somewhat challenging if the members of your hive-mind are the size of ants. Have you read Vernor Vinge's ***A Fire Upon the Deep***? The distributed-mind creatures in that are close to human-sized and use ultrasonics. The ant mind in T H White's ***The Book of Merlyn*** is also worth a look; it is fantasy rather than SF, but it has some ideas about the psychology of such a mind IIRC. [Answer] Real world ant, bee and wasp colonies (and I'm guessing also termites but know little about them) are hotbeds of competition and internecine struggle. They are not the perfect 'hive mind' they are depicted to be. For instance in some species the worker sneakily lay eggs when the queen isn't looking. The queen not so sneakily eats their eggs when she discovers them. In others, multiple queens found a new colony and then compete to become the reigning monarch. Or the workers murder the queens one by one until there is only one left. Drones compete to mate with new queens. And so on. So you need a mechanism to eliminate all this competition. The most obvious biological solution is to make them all **clones of each other**. If everyone is genetically identical, then no-one is favouring their genes above anyone else's. So perhaps you could have an ant species which reproduces like aphids (greenfly). When the going is good, the mother (your founding queen) churns out identical copies of herself. It is only when times get tough, that the aphids switch to sexual reproduction and produce winged males and females to fly off to find some new place to live. Because ants are to a certain extent controlling their own environment (building a nest to protect from weather & temperature, gathering food, cultivating fungus) they'll spend most of the time having clones. The winged ants that head off to found a new colony will not be clones - they'll have their genes mixed up as normal. Downside: disease will go through a colony of clones like wildfire, since they all have exactly the same resistance, same 'blood group', and so on. [Answer] I personally subscribe to the slightly radical hypothesis that in fact not only is it possible, its actually very common. I am a panpsychist and have the belief that consciousness is actually fundamental to the operation of reality. That even cells have their own consciousness, however that consciousness is nothing like human consciousness. Its "Cell" consciousness, whatever the hell that looks like. But it looks like something. And somehow those individual cell consciousnesses become the collective consciousness that is you. Its unexplained how that happens but then consciousness is pretty much unexplained anyway so you don't lose much there. There *are* good reasons for believing that things operate this way, but they are far, far to complicated to explain here. There is a widespread assumption that its incompatible with physics but it turns out it isn't. Physics is based on Quantum mechanics and General relativity and once you grok them it turns out the two ideas are perfectly compatible. Once you accept that somewhat radical position then its a pretty easy step to extend it to societies of multi-cellular organisms. If collections of cells can become "one" without any real explanation then it follows that collections of multi-cellular organisms can become "one" without any real explanation. And I believe this sort of thing happens all the time already with *humans now* but those consciousnesses tend to be weak, contingent and fleeting. Interactions do seem to be important. If the interactions are tight and strongly coupled then you get strong consciousnesses (like individual humans). If the interactions are loose and weakly coupled then you get weak consciousnesses (like humans unified by a sporting match, musical concert or other common cause) [Answer] With ant's there are at least 2 major obstacles, preventing them to be sapient. * Speed of information transfer and mobility. Also maybe more fundamental, system as whole(or some aspects of it) which makes anthill an anthill and limits size. ## Speed, information For ants, we can imagine system which allows to transfer and work with information, bits of it. And that system makes some useful results. We can, because they already have such systems. But what makes system, which others have, mammals and others, useful? * It's fast. Someone may be dumb but fast, and be successful. * It's energy efficient comparing to what it does (helps find new energy and in some cases prevents being energy for someone else). Smarter someone is - better it might be at finding food or preventing being food himself. * It allows to learn, tune(learn) actions fast, on the fly in some cases. Even for a snail, which needs 20-30 lessons in simple cases, which it may comprehend according to it's smartness level, it may take just a hour (not sure about time, just assume it repeats some actions once in 2 minutes, maybe a bit to fast for it, but in general 2-3 hours it think is reasonable amount of time for it, and it may be smarter then that, Helix pomatia used to be laboratory snail, because of relatively simple structure of neuron networks and bigger size of nerve cells). Smart-fast-energy efficient - at some extend any from this triad may compensate imperfection of other two. You may be fasts, but not smart not energy efficient - as example Mustelidae in general or Polecat, Mink([just funny, mink farm](https://youtu.be/hoEN355PhmY?t=173)) as example. Can't find atm and can not recall - saw somewho from Mustelidae smaller, just little bigger then rat, they are so crazy, so target driven, all time in movement, all brains in killing it's pray, nonstop - but also they like to play and are funny. For wide range of combinations, it can be found a species, which will express this combination the most, air, ground, see, deep see. But brain principles(I mean neuron cells) are same. It shows how flexible that system is, it works from no brainers to relatively smart creatures. In all these cases speed of signal (20 m/s, differs in some range for different species), efficiency(element is few cells, even if the are bigger then usually still a cell, so they consume less energy then significant size multicellular organism), compactness (it's a boost for and speed, and efficiency, and mobility) - these properties are vital for systems, which we may observe atm. $\small \text{Ants}$ For system based on ants interaction, as separate elements of such system Can it be fast, as information processing? With chemical and physical approach, no. Way to slow, just reacting to food stimulus in their current stage it may take them 15-30 minutes to react on food presence. And it's kinda typical time of their thinking, few bits tick. Ants as messengers, as information carriers, they have zipp back and forth at 20m/s speeds and actually way more then that - depends on size of that ants-brain - to gain proper speed of thinking. Dense packing of information and processing it - when it goes about mm size creatures. If we take big cell 0.1mm and small ant 1mm - there difference in volume 1000 times, roughly speaking 1000 times difference in energy consumption for 1 bit processing, storing. If their speed is 2 cm/s it means 1000 times slower signal processing, and because of size which will be 10 times bigger (linear difference instead of volume) it will be not 1000 but 10000 times slower. So to reach some rabbit brain processing power smartness(let say 1kg), it have to be 10'000'000 bigger. It's 10000 tonnes anthill, just in ants mass. (feeding and thinking capabilities proportional to small rabbit) Funny thing, principles behind information processing, for most(if not all, I mean, I just doubt a little about bacteria's and viruses, but looks like the do) of creatures we observe on earth, are so much flexible, that it works with ant's even in case of such efficiency difference. It works, but in same time it prevent's them to reach rabbit philosophic ability's(rabbits are hedonists - eat and propagate life, and they are good at that). ## Mobility Mobility, another thing which makes brains and similar systems as useful thing. Constantly changing environment, changes are introduced at least trough moving in different parts of that environment, full of other moving things which wish to make energy from others moving things, and do not let to make energy from them self. In this sense even mobile ants colonies, are not mobile. Rabbit is small and available information around him, is kinda small (field of vision(compact, eyes), sound which reaches place where he is(compact, ears), odors which reaches his place(compact, nose)) - so information is reduced, at point where it is collected in amounts it reach these points of information collection, and because of such reduction he have to think more to recreate important for him information which is behind these bit that reached him, but because of that fact it is reduced, he is capable to work with it, it fits in his small brains, would it be more, he would have difficult times just to filter that information, he could do that, but price will be loosing higher abstraction layers. Ant-rabbit is way bigger then usual rabbit, and surrounded with tiny bits of information like white noise. Noise because it's not important, nor critical for him, and he is't capable to process it all, too much information. And because of size it easy may let him ignore it - eat what can be eaten, eat what moves and so on, on "reflex" level - no need to think. **Ant-rabbit as mobile and stationary system** have major flaw in each state As mobile system, because of it's size and weak structure (as whole structure strength, not as elements(ants) strengths, but binding energy between elements) can't be 3d structure, it have to be flat and this will reduce speed of his thinking drastically, also it will reduce theoretically possible complexity for it(it will be dumb as rock if short). Although it may exist in that form for migration as example and so on. It still can feed himself, react, protect - reflexes will still work, it do not need brains for that. After he can dig-build-find anthill to reassembly 3d complex structure, and get his consciousness back. And there another problem how to feed himself in that situation. He is big. It needs lot of food, lot of water. Human need let's say 100kJ/kg per day (just for rough estimation, human needs 8-10MJ/day). Ants-rabbit may need something around 1/100 of it's mass food a day, that is 100 tonne per day. Grass grow 40 tonnes per $km^2$ per season, let say 100 days for simplicity, means $0.4 tonne/km^2$ so it means ants-rabbit needs $250km^2$ area just to feed himself daily, and 1.5-2-3-4 times more for purveyance for time when grass do not grow, in case to keep that place productive. Way to much for his elements, big for single organism (but not totally impossible [Trembling Giant](https://en.wikipedia.org/wiki/Pando_(tree)) he is 43 hectares (106 acres)) Also [Army ant](https://en.wikipedia.org/wiki/Army_ant), they do that not for fun. Also ants do not eat vegetables only, and there are lot of reasons, if they would then they easily would exterminate grass in their reach, but living pray is attracted but that grass (for different reasons) and that extends ants reach and energy collecting capabilities and prevents them from exterminating their food sources. Ant's surrounding is a big bait. If ant-rabbit will keep photosynthesis plants to produce energy for him, still insane areas needed for such weak internal organisation. Potencial barrier to get consciousness is so big, this may get it with higher probability and speed [Slime mould solves maze puzzle](http://www.abc.net.au/science/articles/2000/09/28/189608.htm?site=galileo&topic=latest) * Slime, may be used as media for ants to process information, and as symbiotic part of system may actually solve some problems in getting that consciousness-brains. Maybe even in natural way, after ant-rabbits will eat everything on planet except symbiotic parts. But will it satisfy you as ants consciousness. ## Size limits As above there are some big problems to solve, and to get that possibility to solve them, ant-rabbit's have to eat and destroy everything except them selfs. Ant-rabbit have great advantages and great weaknesses, too polar in his strength-weakness and not capable to solve these tasks in it's initial form surrounded by other creatures. On top of that, getting brains and consciousness is't easy task by itself, I mean to level, where you may solve problems which you do not have to solve, when it may solve problems which it created for itself. Any living creature, may and solve (as spices, and at some extend as individuals) problems which it have to solve. All these who did't, or failed at some point - are no longer living. All that processes takes time, this is race, and cell have leg-up in that race. But even if we place on start line ants and cell - cell will win. Ants playing cell, have not chances to win race. And first ant-bear slime will rip Ants-rabbit apart, even for Ants-human, Ants-million-humans, Ants-1000millions-humans-pre-1963techlevel-science-approach it will be a problem. Too fragile on each point in time, until it gets real smart and advanced tech. Probably, ants-rabbit have to be created, to skip all that fragile development. Or environment have to be created to prevent breaking factors, but it will unpredictable limit abilities of such system to develop itself. Being friable structure, it's very tricky to affect environment. I mean, elephant may move trees as whole, can ants do that, piece by piece yes, as whole very tricky, they may, but it will be already more complex task for them then for humans. (just imperfect example to show, idea) ## Conclusion Possible, but natural way highly unlikely. Is there sense-point-value-meaning-significance-spirit in to creation of such systems? $Yes.$ We are pretty good at creating problems for us, and at solving them. But also we are limited in types, approaches, classes of such problems. And to be able breach boundaries of our collective consciousness, we have to solve new types of problems, and for that is't reasonable to create another creature with another types of problems, which will be not typical for us. It may create both types of problem have-to-solve and do-not-have-but-may to solve. Besides, it's interesting task by itself. If we survive, then in not so much distant future there(in this star system) will be no problems we can't solve (except our typical problems), and probably few more fundamental problems. And to get ability to solve more fundamental problems, and be better at solving our problems, it might be good time to get new toy, which will teach us by it's problems by it's existence, which will transform our ways of thinking farther. Next race we have to begin and to race. Actually space may be good place to create such ants-brains. Less restriction from gravity, less energy to redistribute food-energy, more energy in general - all energy size restriction will be less strict. [Answer] As far as I can tell, absolutely. But the fact that an infinite amount of sapient species theoretically exist helps this a lot. Fire ants are known to create rafts during floods, so perhaps the bonding behavior of these ant-hills results from a long lasting flood. ]
[Question] [ I'm working on colony development. The word is similar to the earth around 5000–4000 B.C. and humans basically known how to hunt, farm, build houses/structures and share their knowledge between them and their kids. We have a group of these people (let's say around 300) who wants to build a sustainable colony starting from almost nothing. They have enough food (but not usable seeds) and water for some weeks, rudimentary clothes, a small amount of basic tools and some flints/firestones. So they shouldn't be dead for the next few weeks :) I'd like to know what kind of environment is the most favorable for them? What are the most important resources to gather and farm in order to properly start this colony? I thought about a large forest in a moderate climate (Mediterranean?). They could find water sources, gather berries, hunt wild animals, get wood for houses and fire, and rocks for their tools. Do you see a better place to start? If you had to select the ~5–10 most useful/mandatory raw resources (fitting in the same environment), what would you choose? [Answer] I believe what you are looking for are **river valleys**. Many, if not all major ancient civilizations who settled down to permanent settlements could only do so because they were able to learn agricultural techniques and they needed fertile land to do so. Look to the Egyptians and the Nile, as well as the Tigris and Euphrates in Mesopotamia. There are many more examples in other parts of the ancient world. **Food and fresh water.** Sustainable food sources along with fresh water are the most essential things for any human settlement. River valleys provide for an abundance of fauna and diverse wildlife for your colony to make use of. This is besides the fact that they offer some of the most fertile land you can find for agricultural uses. **Shelter:** Since you will need some form of shelter a river valley allows for you to choose a few options. They could build brick homes from clay found in the river. Wooden structures from great forests growing along its banks, or maybe even use the river to transport stone from quarries they mine up river. **Trade:** At some point the world will start getting smaller and the population of your colony will get bigger. Trade will be something that most likely you will participate in. The river is a natural medium for this as most major rivers either lead to some major body of water and are navigable. **Some form of metal:** You are going to want some source of metal, so that at some point you will be able to allow for technological advancement. Now what you decide to use will be subject to how you want your colony to grow and interact with the world. I do not think it is essential to have it right next to the initial settlement but within a reasonable distance, there should be some sort of easily mineable metal such as gold, copper, tin. [Answer] The best location is generally a sea shore with a source of fresh water. A cliff with caves is the best low tech shelter. Caves actually give better protection from weather than most buildings. Before large scale fishing oceans apparently had orders of magnitude (yes, **plural**) more fish. A coastal area with good fishing due to upwelling, plentiful molluscs, or even seals unused to humans could easily support small human colony without much effort. Coasts with cold currents are generally more productive since the current lifts nutrients from the deep. A source of fresh water is a basic necessity for humans. And many other large animals so a good source of fresh water usually implies good hunting as well. Areas with low population density generally have significant seasonal food resources in the form of fruits, berries, and mushrooms. There are of course also plants with edible leaves and roots, but those might be less obvious. I think the traditional theory of discovery of new food sources is to observe what other animals think edible and then experiment cautiously. If there are only few hundred people and the world is uninhabited, hunting, gathering and fishing should support them comfortably. So generating new food sources would not be a priority. In fact with a good starting location there would be no urgent priorities, I think. It is easy to forget, but we actually evolved to survive **without** civilization. Good technologies to preserve to the next generation despite no urgent need might be pottery, making thread and nets, maybe boats. Making salt (or just brine) from seawater and using it for food preservation would also be good skill. A small garden might be practical and help keep the idea of agriculture alive. [Answer] To answer this question I (somewhat surprisingly) turn to [Dwarf Fortress](http://dwarffortresswiki.org/index.php/Main_Page "DF wiki") and its associated wiki. Dwarf Fortress (DF) is a game about... building a sustainable colony/fortress starting from almost nothing. It is also highly detailed and quite realistic. **Location:** An ideal (ie: easy to settle) starting location in Dwarf Fortress has several key features: * Easy access to fresh water, like a river or stream. This is mentioned in some of the other answers as well. Easy access to a river also provides fish and (depending on your setting) irrigation. If your river periodically floods like, say, the Nile, then your colony gets free irrigation like the ancient Egyptions did. * Mild/Hospitable weather. A hard winter right after settling could easily freeze all your settlers. Hot weather is less of a concern if you have access to a riverwater but extreme weather places you colonists at risk of heat stroke and/or melting. * As other answers have noted, you will at least want one metal ore in close proximity to your colony. Metal is useful for better tools, weapons, etc. and has economic value, but that might not matter to your colony yet. * In a primitive society, trees are also very important resource as fuel and as a construction material. If your colonists know how to work metal (copper, tin, bronze) or want to make glass then trees also become a source of charcoal which is neccessary for any serious smelting/glass making. * Food. Duh. Rivers provide some fish, plains and savannas (like Africa) provide larger herd animals and grains. Forests *may* also have eadible plants. Trees will have edible fruit which have seeds. If your settlement is near an ocean then salt is also valuable because it can be used to presurve meats. **Resources, Tools and Knowledge:** Many DF players tweak their starting resources too: * You mention that your colonists have several weeks of water with them. I have a problem with that; water is really heavy. A Litre of water is one kilo. and one human needs 1-2 L per day depending on exersion. Two weeks of water is (worst case) 28 KG. That is alot for one person to carry. It is far more likely that your colonists followed a river. As user2389345436357's answer states, you will probably be looking for a river valley (like the Nile) for your colony. * Your colonists should take along knives, both for self protection and hunting. In some early cultures openly carrying a knife was a simbol of status as well. Your colonists should also have the knowhow to make shelter for themselves. * It is best that your colonists have a wide variety of skills. In DF, you would typically start out with a Mason, Carpenter, Woodcutter, Miner, Fisherman, Fish cleaner/disector, Butcher, Tanner, Farming, etc. Consult the full list of skills [here.](http://dwarffortresswiki.org/index.php/DF2014:Skill#Skills) Of these, the Fisherman, Butcher and Carpenter will be most useful in providing food and shelter. Later on your settlement might want glass makers, metal workers and masons. Once you have seeds (hopefully) from the local plants farmers will come in handy. Note [this](http://dwarffortresswiki.org/index.php/DF2014:Starting_build#Design_Constraints:_Which_skills_do_I_need.2C_really.3F) list of starting skills and other considerations. * The local animals might be hostile and unsuitable for tameing: if possible your colonists should take along animals as pack animals, for leather, producing meat, milk and (later) cheese. Goats and llamas might be a good choices, they both produce milk which can be made into cheese, wool for clothes, and can act as pack animals. They are also produce edible meat. * One last point - have you heard of the 50/500 rule? Basically, 50 people is enough for short term survival, and 500 or more are needed for long term survival. This has to do with [genetic diversity](https://biology.stackexchange.com/questions/9388/), if your group of people is too small then inbreeding becomes an issue. According to Wikipedia's [article](https://en.wikipedia.org/wiki/Space_colonization) on Space Colonization, [150-180 people](https://en.wikipedia.org/wiki/Space_colonization#Population_size) should provide enough genetic diversity to last around 60-80 generations, or 2000 years. 300 colonists should last significantly longer than 180, but 500 is a fairly well quoted figure for long term (10000yr+) survival. **TL;DR:** You want a temperate climate, a river or other fresh water, wood, fruit, fish, butcherable animals, more wood, and ores of your favourate metal. --- You might benefit from reading the [Dwarf Fortress Wiki](http://dwarffortresswiki.org/index.php/Main_Page "DF wiki") (link above) and/or [playing the game](http://www.bay12games.com/dwarves/). Dwarf Fortress might not be the best way of simulating your colony but many of the concepts are applicable. [Answer] Since you explicitly have eliminated seeds from the supplies the people would have, they should retool themselves for a nomadic hunter/gatherer existence. Living as nomads isn't a huge stretch for people, the world's population is descended from hunter/gatherers and that lifestyle was around even into the late 1800's in various parts of the world. You did not mention horses, but if they have horses then they will be able to go one better and become nomadic pastoralists and even horse raiders as well. This would also imply they can get a source of livestock along with or shortly after getting horses. As nomads, they would not need (or even be able to carry) lots of goods, so basic tools to hunt/fight, butcher, clean and dress animals, and manipulate the skins and wool for shelter and fibre would be the 80% solution for these people. What they need after that they can trade meat and skins for (if they are traders) or raid the settled agricultural settlements to get. (Historically, it was usually both). [Answer] Depending on the skills/knowledge of your colonists; raw ore on the ground, and trees to go with it - since you've implied water and animals are available. * High quality iron ore (detectable by magnet) was available on the surface in the US as little as 150 years ago, when MI and MN were opened up. Iron tools go a long way towards... everything. * Coal beds nearby would be nice, instead of having to barge the ore to the coal, which is what happened historically. Alternatively, you could make-do with charcoal, which takes trees and dirt (helps if you have an iron shovel...), which leads to: * The right trees are next most important (fuel; tools: bow & arrow, ax-handles, shovels; buildings/machinery: tepee poles (valued at 4 horses apiece on the Great Plains), houses, lumber-drying sheds, mills; transport: barges, wagons, carriages). * Finding plants you can start to domesticate, since you're refusing to let them bring seeds. Crops may take quite a long time to develop. * Domesticated horses that they brought with would be *very* useful; transport, transport, transport, and horse-power to run mills/machinery that you need before you can make engines. Same for goats and/or to a lesser extent, cattle (both of which covert the landscape to food). * You'll also need some good clay deposits to make kilns/firebrick with. [Answer] At around 3000bc is when we first started building pyramids, so they would be progressing rapidly towards organised settlements with civic structures. I agree with the river valleys answer, particularly about the metal. Salt is also a crucial factor as our brains require salt to process properly. (salt was used as a currency in the roman and pre-roman eras). According to a research paper\*, it is also the only taste we are born to like, all others are learned. Something to remember is that the odds that there would be life on another planet that would have the right proteins for us to consume without being toxic is very remote (they may not even be carbon based.) So maybe have the original fauna & flora as well as introduced ones, could make for interesting complications (if earth flora can only grow in certain areas etc) **Edit**: \*There are a few articles here, I cannot remember the specific one I was referring to, but it was a neurological basis paper I read about 5-7 years ago. Here are some others, the first of which has to do with the lessening of the salt in infancy as the child ages: "Infant salt taste" (GK Beauchamp, BJ Cowart, JA Mennella), "Intersalt: an international study of electrolyte excretion and blood pressure." BMJ has arguments in it that both show nature and nurture arguments. Salt also helps with control of our blood osmolarity and is used for conduction within the brain. Of course too much also causes heart and blood pressure problems. Too little salt in the body can induce episodes of symptoms with eerie similarities to dementia/Alzheimers and can lead to death (I know someone who had this happen, she survived thankfully). ]
[Question] [ I am creating a semi-dystopic sci-fi world in which the government is - surprise, surprise - corrupt and needs to be replaced. In books, this is often done via warfare and violence, but I would love to find a way to do it without war and yet not have the story devolve into a series of political debates or "get out the vote" rallies. Similarly, I can't afford the time span (or cast) required for slow-moving revolutions like the Enlightenment or the Industrial Revolution. Any other ideas for replacing a government? [Answer] A few ideas: * Use the judicial system. Somehow get a critical number of the main politicians all arrested and/or evicted from office, all at a critical time that isn't anticipated, so that enough non-corrupt leaders can end up taking their places. * Use non-corrupt media, and/or infiltrate corrupt media, and suddenly make enough people agree that things have to change. Drama, music, and comedy may be some of the most effective media. * Convince the string-pullers to change their minds. I.e. if your politicians are corporate pawns, you might be able to get your ideas to make sense to enough corporate heads so that they issue amended instructions to their bought politicians. * Convince the spy-masters and intriguers to change their agendas. If elections are rigged farces, if you can convince the people rigging the elections to rig them in favor of a new group of opposition leaders, you could break the corrupt block's control of the government that way. * Infrastructure collapse. If power and/or information systems shut down for long enough, a new reorganization might happen as people are forced to recover from the crisis everywhere locally. If it lasts long enough, once things are restored, the old government and power-structure may have lost dominance, relevance, or have fled or disappeared in the chaos. * Out-corrupt them. An organized campaign to scandalize, blackmail, implicate, threaten, or otherwise manipulate many corrupt high officials at once, might be able to get enough of them replaced. * Out-intrigue them. If the corrupt governors are dangerous paranoid scheming types, infiltrate their confidants and get them to scheme against each other. Replace a few of them with people who are actually on your side, and have them eventually be the survivors of the political backstabbing. * Turn the police and military. Perhaps the corrupt authorities have instructed the police and military to murderously crack down on civilians in times of unrest, and it looks like there are enough protests that it may come to that, but you've generated enough sympathy in the police and military leadership and culture, that they refuse to attack civilians and instead demand the corrupt politicians resign. * Cyber campaign. Gain control of the media, communications, utility, and/or financial computer systems, in such a way as to get rid of the corrupt officials. Many options here. If you can control any or all of those types of systems to enough of a degree, there are many possible ways to effect a political revolution. [Answer] Although not always *entirely* without violence, there are plenty of examples in real-world history — enough that there is a whole [Nonviolent revolutions category](http://en.wikipedia.org/wiki/Category:Nonviolent_revolutions) on Wikipedia, and a [page on the topic](http://en.wikipedia.org/wiki/Nonviolent_revolution). For example, read about [Velvet Revolution](http://en.wikipedia.org/wiki/Velvet_Revolution) which took place in (then) Czechoslovakia over about a month and a half in 1989. In this case, and I think in general, there are two common themes: * Civil disobedience as a tactic * World politics as an important factor — collapse of supporting governments (as for example totalitarian/communist Warsaw Pact states) Another common aspect is unwillingness of the military to act against their own people — sometimes extending up to the military leadership and leading to a bloodless coup (or nearly so). In a future dystopian story, this could be the techs responsible for maintaining combat drones — or hackers taking over their control. All of these real-world stories feature strong personalities, intrigue, and high-stakes tension — the possibility of collapsing into violence or tragedy is always there. I don't think you need to rely on dry political speeches at all. [Answer] **If the people have motivation and cooperation** then an easy solution would be a march on the capital. Something similar to the MLKJ march on Washington. If the government is corrupt, it is likely they would use the army to prevent this from happening, even going so far as to kill citizens. Harmless protests such as the Hong Kong protests, where the Chinese government gassed [its own citizens](http://www.bbc.com/news/world-asia-china-29398962). In situations like this, if the population really believed in its dream, they would over power the government in sheer numbers. Generally, the army is not big enough to fight off thousands of people pushing their way -- without fear of death -- to the capital to fight the oligarchy. Generally speaking, a government would not want to slaughter its citizens, no matter how corrupt. Being in places of power over people is only useful if those people are around, so if they are dead it will be hard to have the power. In addition, there are many political problems with mass slaughtering citizens; if there were another country like America in your world, it would most likely go to war with this man-slaughtering government. I digress, if the people have a spokesman who can rally them, it is usually game over for the government. **If some politicians aren't corrupt** then those politicians could influence governmental decisions by voting for or against certain actions. This is assuming it is a democracy, or some form of dictatorship in which more than one person is in charge. If it is only one person, politicians could over throw the president/chancellor/general by disobeying orders, whatever that entails. Not passing on information, causing the Commander and Chief to fall into a trap, perhaps. **If a company has money** then the company could buy out the politicians. Assuming they are corrupt, more money would be welcome. If the tech giant did not completely control the government (directly make decisions, such as "I pledge allegiance to the United States of Walmart"), then they would be able to manipulate the politicians to cast votes, or to not pass on information to their Commander and Chief, etc. If you're thinking the government would shut the business down, you're wrong. The business would be sensible enough to hire its own mercenaries and fight its way to the capital if need be, or at least defend its operations, factories/plants, and HQ. **If there are immigrants** then the new population could influence the votes in just a generation or two. This may seem racist, but flooding a country with new citizens has a huge impact. Once those citizens' children are of voting age, they could easily be 20% of the voting group, which is a big deal in politics. Such groups could even make their way into political offices, and get voted up the chain of command. In this case it would be best for each family to have four or five children to adequately increase the votes. **If necessities are held hostage**, such as water sources, food sources, and power sources, then those can be used as bargaining chips. If these are controlled by a company, a mass of citizens, or armed troops opposed to the government they can threaten the government by limiting access. Taking out Hoover Dam or a nuclear reactor would certainly slow things down and get attention. **Notes** Most of these situations assume that the population of each group act as one entity, like an ant colony. This is dire for the operations to work. One person in the group with information could leave the cause and foil all the plans, even get people killed. There needs to be trust, motivation, and leadership in any of these overthrowing parties. [Answer] Dissolve large amounts of LSD on the water supply. While everyone is having a trip, destroy all military equipment besides your own, now wait for everyone to return from hallucination and force your way to the government. As the military has no weapons to fight and the population is, hopefully, not mad about the collective drugging and angry at the dystopian government failures, the balance of power will shift towards you. [Answer] The world doesn't need another political manifesto. And it seems you don't want to write one. > > ...not have the story devolve into a series of political debates or "get out the vote" rallies. > > > So, why not have a complete and total deux-ex-machina? Some magical character or magical artifact that causes the reversal of fortunes you seek to bring about? For example, the *Narnia* series features a witch who sets herself up as queen and brings a century-long winter to the realm. This is brought to an end when a magical lion, and four children teleported into their universe from a magical closet, confront the queen's forces in battle (yes, some violence there). Make a non-violent version. In the previous volume, Aslan created the world by singing. Create a version where the Aslan stand-in character ends the winter and melts the queen's cold heart with song. (Is that the plot to Disney's *Frozen*?) Also consider some magical artifacts. Arthur had a sword that only he could pull from the stone. He also had a magical scabbard that would prevent him from dying in battle, no matter how badly injured. Even more impressive the the [Point of View Gun](http://en.wikipedia.org/wiki/Technology_in_The_Hitchhiker%27s_Guide_to_the_Galaxy#Point_of_View_Gun "Point of View Gun") from the Hitchhiker's Guide to the Galaxy. Anybody fired at with this device is immediately able to consider the merits of another person's opinions, no matter how close-minded before. Wow! Another plot device you can use is dreams, or some other means of psychological epiphany (preferably unbidden and unwanted for the recipient, as dreams are). In *Robinson Crusoe*, the protagonist sees a deity eponymously named "Defoe" (after the author) in a frightening apparition in a dream. In the New Testament, it is said that Pilate was reluctant to crucify Jesus because his wife had a bad dream and warned him. This seems quite unlikely for a number of reasons, but it works in fiction. Have somebody appear from *our* universe into the fictional world to intervene, like the kids in *Narnia*. Maybe have the universe itself correct the situation. Signs and messages from the stars and planets, maybe messages from insects, talking animals, and sentient plants, *a la* the movie *Avatar*. I've got it. Perhaps the head honcho has some illness or physical affliction, so he starts experimenting with smelling, or eating, a mysterious plant. This unknown, mysterious plant magically makes him calm, a little bit absent minded, and empathetic--and less prone towards violence and tyranny. He no longer forbids this plant to his subjects, and others start eating and smelling the plant as well. Meanwhile, the hardliners of the government are displeased. They try to enslave innocent young men to become goons for the war machine, but they escape to the Magical Wintery Kingdom of the North. At the same time, some strange messengers appear from a faraway land, and start talking about their dreams and singing songs about imagining things and foretelling the coming of a new age. The masses worship and honor the new messengers and their songs become known for generations. That would make for some pretty interesting fiction, in my opinion. [Answer] In Eric Frank Russell's **Late Night Final** story (PDF available on web in Google search) Earth is invaded by a squadron of ships and the people don't resist. But they also don't cooperate and eventually absorb the invaders into their society, because it is the better one. > > "They brought with them weapons of considerable might, not knowing > that we have a weapon truly invincible." Waving one hand, he indicated > the world at large. "It took us thousands of years to learn about the > sheer invincibility of an idea. That's what we've got—a way of life, > an idea. Nothing can blast that to shreds. Nothing can defeat an > idea—except a better one." He put the pipe hack in his mouth. "So far, > we have failed to find a better one. "They came at the wrong time," > Meredith went on. "Ten thousand years too late." He glanced sidewise > at his listener. "Our history covers a long, long day. It was so lurid > that it came out in a new edition every minute. But this one's the > late night final." > > > [Answer] What came to my mind is Heinlein's ["The Moon Is a Harsh Mistress"](http://en.wikipedia.org/wiki/The_Moon_Is_a_Harsh_Mistress). Of course you cannot steal the plot right away but the core idea is that the very central computer which is involved in everything (if you can have such a character) must be at the same time (a) the most sensitive spot of the ruling system (b) one of the best computers around, so on the verge of becoming really independently thinking and (c) by the nature of computing specifics, influenced by pure logic and reason more than by anything else. In Heinlein's novel this is pushed to the limit in that the computer is so much intelligent that it develops its own sense of humor, quite subtle, and is craving for somebody with whom to communicate in the corresponding mode of communication. One slight inconsistency is that somebody who is willing to overthrow the government turns out to be one of those who have free private access to the guy (some IT technician). The rest is clear - once they become friends, it is just the matter of purely logically explaining to the machine that the government is worth overthrowing. [Answer] I recommend the idea from David Brin's book "Earth". If the government gets to be too much of a nuisance just unplug them from the Internet and carry on without them. An interesting example of a real revolution was the Russian revolution in Feb 1917 when the Russian soldiers fighting against Germany in World War 1 decided to leave the war and head home. Not bloodless but surprisingly without much violence. The big problems came later after the Bolsheviks seized control in October. It is an interesting case because as the "first" communist revolution the majority of the violence came after the revolutions when everybody else figured out what was going on. So if you want a quick (low violence) revolution you have to come up with something that hasn't been done before. [Answer] A centralized charecter, like a prophet who has the capability to convince people to make sacrifices for the greater good. Which will be the first to unravel, the corrupt governments hold on her citizens or the "machine" behind the engineered perception of your prophet? [Answer] Re-reading [my answer](https://worldbuilding.stackexchange.com/a/11928/7900) another closely related plot came to my mind, this time from the first story "The Gargantian trap" of Stanislaw Lem's [Cyberiad](http://en.wikipedia.org/wiki/The_Cyberiad) According to Lem, this is in fact a classical trick well known to experts (such as the main characters Trurl and Klapaucius). Encountering a planet with two halves of the population ruled by two tyrants at war with each other, Trurl and Klapaucius split, each offering to his host the same idea: the ideal army is the absolutely unanimous army, so all soldiers must be switched together into a single individual. Both rulers are excited about the idea and start consolidating their armies at high speed. What happens is that after certain critical amount of individual minds joined into a supermind, the latter finds the very concept of war totally meaningless, so on the final battlefield two of these superminds just go for a walk gathering flowers along the way. [Answer] A [General Strike](http://en.wikipedia.org/wiki/General_strike) might work. If a large enough portion of the population simply refused to go to work it would cripple the economy and force the corrupt government to react. If the government reacts by mobilizing troops against the civilian population there's a reasonable chance that soldiers may have an ethical problem with using force against unarmed civilians in their own country. Soldiers may begin to go on strike as well. With the workforce and the military on strike the government effectively looses power. [Answer] I would suggest the "Libertarianism as a social movement" idea. As communications technologies like the internet become ubiquitous and other technologies become cheap and common enough that people can successfully decouple from the various "grids" (electrical, water system, banking system, healthcare etc.) they will discover they can plan and do many things that were formerly the domains of the government due to the government's ability to mass resources. Governments can (and do) try to squash these systems (look at the battles between governments and government supported monopolies like the Taxi system and Uber), but the end result is governments and their clients look corrupt and incompetent, the masses of people who benefited from the new technologies and the people who created the new systems get pissed off and work even harder to bypass the "gatekeepers". Other changes occur as old market leaders and dominant corporations are simply outcompeted and loose their commanding market positions. The various power structures and systems which support them become increasingly irrelevant, and if/when they eventually collapse, the people who "unplugged" from the system first are able to thrive and prosper. ]
[Question] [ I'm writing a story in which a character has to make it through an area filled with aerosol poison...or something along those lines. He starts out in a hospital area, with access to equipment. Is it feasible that he could just put on an oxygen mask and be adequately protected? I think hospital oxygen masks are just to supply EXTRA oxygen, and not keep other stuff out. So...wanting to make sure this plot point doesn't have any leaks (pun intended ;-) [Answer] # It Depends... ...on which kind of mask your character finds, and if they know the difference. A standard mask used to administer oxygen, air and anesthetics: [![enter image description here](https://i.stack.imgur.com/QvZcy.jpg)](https://i.stack.imgur.com/QvZcy.jpg) A standard mask used to administer only oxygen: [![enter image description here](https://i.stack.imgur.com/DpiTc.jpg)](https://i.stack.imgur.com/DpiTc.jpg) If you character knows what to look for (and where in a hospital to find one), the first will do well enough, if properly sized and worn. This kind of mask is designed to work with the coaxial gas delivery / evacuation tubing that's attached to an anesthesia machine. The hose attaches to the opening at the top, a rubber head-band attaches to the four prongs, holding the mask on the face. At the bottom is a soft plastic balloon that surrounds the nose and mouth. The second mask is designed to provide "blow-by" oxygen. This mask is a slightly harder plastic whose rubber band attachment is quite flimsy and weak (by design). This kind of mask can be found almost everywhere in a hospital and is designed to hook up either to the central O2 system or to any portable O2 tank. This kind of mask rests lightly on the face and is, by design, very leaky. **Problems:** Obviously, the second mask will admit aerosol poison along with oxygen or air from the tank. Ungood, that. This could, however, be the cause for several hectic MacGyver moments as your character realises that the mask isn't going to be quite up to the task. This is why God invented Tegaderm film dressings. Just glom a bunch of those all over the face and mask, taking care to seal up the O2 delivery tube and Bob's your uncle. [![enter image description here](https://i.stack.imgur.com/hclzl.png)](https://i.stack.imgur.com/hclzl.png) Should your character obtain the first kind of mask, they'll need a "converter" to go from the O2 tank's small gauge hose to the large opening. Part of the anesthesia supplies is an ambu bag which will do the conversion. Still, this mask isn't perfect! These masks are designed to keep anesthetic gasses inside the circuit (OR staff headaches from leaking anesthetics are not uncommon); but they're not designed for long term use and they certainly aren't designed to keep poisons out. Even when strapped to a person's face, they often leak, especially at the bridge of the nose. Your character will have to carry the O2 tank in one hand and jam the mask to their face with the other. The tank can provide 15 lpm maximum, which should be more than enough to get your character through the Zone of Yuck. Using a standard hospital E tank, your character should be good for about [45 minutes or so at maximum flow](https://www.phc-online.com/O2-tank-duration_a/151.htm). Tanks are notorious being not quite full...so, make sure they check the gauge before grabbing a random tank! **Reality Check = PASS!** Even so, it will be a harrowing and exciting venture with a very high risk of failure. For example, do note that the mask won't protect the eyes, and they, being mucus membranes, are susceptible to noxious fumes. [Answer] Yes, it can work but it depends a great deal on the "aerosol poison" you are dealing with. It needs to be something like chlorine gas. Chlorine works by physically damaging the respiratory tract and pulmonary system when inhaled in relatively large doses. The oxygen mask doesn't need to seal perfectly to protect the wearer and the lack of eye protection will leave the person needing to flush out their eyes when they get clear but should cause no permanent harm. You are also clear of the danger once you get past the poison fumes and into fresh air. With other airborne poisons such as most nerve toxins or blood toxins an oxygen mask is not going to be adequate. Breathing in even a small amount could cause harm and the oxygen masks you are talking about cannot be completely sealed from outside air. An oxygen bottle contains pure oxygen, it is not a SCUBA tank filled with compressed air. Breathing 100% oxygen from a bottle is better than breathing poison gas but pure oxygen can cause be just as harmful if the person breathes too much of it or too long. Also consider that many airborne blood or nerve toxins can be absorbed into the bloodstream through the eyes or even through exposed skin. For these types of toxins you need a full mask that protects the entire face and a full protective suit. (It is possible that such protective equipment is stored somewhere in the hospital as hazmat equipment.) Also, some aerosol poisons are intended to be easy to clear, such as the stuff used when fumigating a house. Other poisons are intended to be longer lasting. They are sprayed as an aerosol mist of tiny droplets that stick to things, including the person and their clothes. These droplets will continue to evaporate and off-gas toxic fumes long after leaving the area where they are deployed. This means that the person needs to keep the gas mask on while following a strict decontamination protocol, stripping off and discarding their clothing and showering off any residue that may be on their skin. [Answer] (Slight) frame challenge, At an high exercise level we need 3.5 litres per minute (average person): [![enter image description here](https://i.stack.imgur.com/lmk0Q.jpg)](https://i.stack.imgur.com/lmk0Q.jpg) This would indicate that if the person were to leave the mask on, given that they would only be able to take shallow breaths, lest they breath in the outside poison air, they'd not be able to get up, walk and in the stressful situation function. They'd either need to: Up the flow rate on the regulator and take lots and lots of shallow breaths - the dead-air space in their trachea would make this impossible to sustain and they'd gasp for air and get poisoned. Or: What they would need to do is rip the tube out of the mask, shove it in their mouth and turn the flow-rate up on the cylinder's regulator. If they need to, then, replacing the mask and doing the inpatient-shuffle along the hall would disguise their escape. [Answer] TLDR: Fit any medical oxygen mask, *then throw a plastic bag over your head*. Done. I paint with 2-part (A and B part) Imron-style paints. The two molecules link up in a conga line of ABABABABABABABABA, forming an extremely long molecule. The magic B-part is *isocyanate*. When it's not grabbing A-parts, it likes to grab white cells. This can really mess up your immune system. It has very poor penetration through skin, but extremely good penetration through lung membrane. If you brush or roll the stuff, the isocyanate stays on the brush or roller. But if you spray it, now it's aerosolized. So the painter is in the same pickle as your hero. The manufacturer recommends protective gear with externally supplied air. It keeps positive pressure in the mask. The positive pressure assures no aerosolized material can get into the mask. That's what your hero needs. Medical masks aren't designed to do that, but the external oxygen or air tank will provide positive pressure if only he could come up with a painter style mask/hood. So the hero needs to **throw a plastic bag over his head** and tie it at the neck with a competent but imperfect neck seal. Once the bag inflates, the mixed inhaled/exhaled air will leak out the neck seal. This will create the same positive pressure that the painter enjoys. Assuming he doesn't have access to bottled air, the oxygen and his exhaled CO2 will dilute and expel the nitrogen in the air. He will be breathing a mix of oxygen and CO2. Which won't be pleasant! Pure oxygen isn't healthy, but the presence of CO2 creates the sensation of being unable to breathe, filling him with a desire to tear the bag off his head. The concentration of CO2 will be decided by how fast he runs the oxygen supply, which in turn will decide how long it lasts. This isn't sustainable for hours, but could get him through a tough area. If he also has access to nitrogen, (liquid nitrogen, used to preserve samples or cool the CT scanner's magnets)... he could make himself a perfectly pleasant cocktail that he could breathe indefinitely, at the cost of additional weight to carry. [Answer] As others have answered, it's physically possible. However, you should note that breathing pure O2 is toxic. I can't find clear figures for 1 bar of O2, but 0.5bar O2 causes irreversible damage in 16h. I'd expect 1 bar to be much faster (not just half the time). Your character would need to be breathing it at just over 1bar, as he won't be able to generate negative pressure. Also even in the short term, pure O2 causes hormonal responses – you should google for more info on this – which is why it's not used for resuscitations any more. There's also issues with the low CO2 levels in the blood. Someone with actual medical knowledge can weigh in and expand this. ]
[Question] [ **This question already has answers here**: [Is Asteroid Harvesting economic?](/questions/5168/is-asteroid-harvesting-economic) (9 answers) Closed 5 years ago. My story is set in a somewhat recent period of time (within let's say 50 years) The material (raw metal and such) are extracted by splitting the asteroid and then sensors identify which pieces of rock are mineral/metal rich. After these pieces are collected they would be brought back to a large mother ship where the pieces of rock would be melted down and the material extracted. Would this process be worth the expense and are there better ways this could be set up? [Answer] Depending on what you're using the minerals for, this might not only be worth it, but it might be the only possible way to access minerals in any quantity. Let's start by taking a look at Apollo 11. The Command / Service modules of the Apollo 11 mission came in at nearly [29 metric tonnes](https://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1969-059A) and carried a fuel load (combined kerosine and liquid O2) of around [2.4 million litres](https://www.space.com/18422-apollo-saturn-v-moon-rocket-nasa-infographic.html) to get it on its way to the Moon. I'll point out here that a ratio of mass to fuel load isn't necessarily helpful here as Saturn V was designed from the ground up to get that mass and size into orbit, but this ratio does show that even if you were shipping equivalent amounts of mass (one load at a time) into orbit to make something big, it's going to take massive amounts of fuel. So; let's build something big. The Constitution class Starship (TOS Enterprise) has several mass estimates that put it in the 180k metric tonne range. This is approximately 6,207 times the mass of the Apollo 11 Command & Service Module launch weight. The cost of launching 17 Apollo missions was considered too much for many Americans and the program was shut down (in part) because of the ongoing costs to the USA. Just getting the raw mass for a starship (not to mention the building crews, habitats, construction frames and gantries, etc.) would be 365 times the cost in fuel of the entire Apollo program. All this assumes that there's this much fuel *to spare* from our dwindling resources. Not practical, and potentially not possible. BUT; we have an entire asteroid belt out there. The advantage (as sdfgeoff points out in his comment) of asteroids is that they have very little gravity to contend with. So, if the minerals are out there in the asteroids, then mining and refining them out there is a better option than trying to get all those minerals off the Earth. The problem is going to be size and mineral content. The Asteroid belt between Mars and Jupiter comes in at a mass of around 4% that of the moon, and we don't know what percentage of that is usable in terms of minerals. Also, much of it is spread out once you get past Ceres and a couple of other really large asteroids making Ceres the obvious starting place. If we're talking around 50% mineral content (and that's likely very generous) you'd have more than enough materials for a fleet of starships, but you have to refine the materials first. That means smelters, factories, and **energy**. That's the biggest issue as we'd need energy out there and as there is no mass extinction of plants on Ceres recorded, there's no oil or other chemical energy store. If we find reserves of Helium 3 though, in quantities similar to those found on the moon, you've got a massive amount (for a time at least) of minerals **and** energy available with very little energy cost in terms of gravity wells. You build your infrastructure first (refineries, factories, construction frames et al) and then whatever materials you have left go into ships or other space borne needs. Eventually, we'd mine out the asteroids and then we'd have to look for other mineral sources in low gravity wells. One that we might consider would be the Moon, as even though there's an energy cost to getting minerals off it it's nowhere near as expensive as getting them off the Earth. Better yet, we'd look at the smaller moons around Mars or even the outer gas and ice giants, but then we'd need to find Helium 3 or some other mineral based energy reserve as well and those sites are remote at best. If our energy needs are being supplemented initially by solar, then their distance from the sun is also problematic. Ultimately this problem comes down availability; not just in terms of the mineral resources themselves, but also the energy required to extract and transport them. Mining Minerals on Earth is possible because we have massive energy reserves. Getting them out of the gravity well however will cost a lot of that energy. Mining Minerals on asteroids would negate the energy cost of getting those minerals into space, but then there's very little energy (outside of a potential fuel for fusion reactors) to use out there in the first place. So, if there's no energy source on those asteroids, then the answer is probably no. It's not worth it because the cost of the minerals comes at a cost of shipping energy up to those asteroids constantly. If the materials are being used on Earth, then again the answer may well be no, because the cost of getting the mining infrastructure up there in the first place would fund what you want to build. But, if you're looking to build things in space and have an energy source available locally to the minerals, then it would certainly be worth considering if you're building anything at scale. [Answer] The value of asteroid mining is the materials already in space. Getting materials off Earth currently costs around $25K a kilo. If the material is already in space, you can build spaceships, space stations, satellites probes, etc without the cost of the fuel to get it into orbit. [Answer] Once you have the technology to get there and back, it gets interesting. There's two main advantages to asteroid mining compared to planet-based mining. As others have noted, if you need the materials for further construction in space, you save a lot in launch costs. But even if you want to ship the materials back to Earth, there's the second bit: most of the material the Earth is made of is pretty much inaccessible to us. We only have access to a thin crust at the very top of a very massive planet. Even worse, many minerals have preferentially segregated deep below the crust, even all the way down to the planet's core. Many of those materials are very valuable - platinum, iridium, gold, silver, many rare earth metals; even iron and nickel. At the same time, there's plenty of ice in the asteroids, which could be used for in-situ fuel processing, dropping the shipping costs significantly. Another great bonus is that asteroids often contain mostly pure metals, rather than ores. This might allow us to avoid costly refining, and greatly increases the yield (e.g. most modern copper ores yield only about 3% of their mass in copper; a 500t asteroid could correspond to 15kt of copper ore in the ground). Aluminium would save a lot of energy on refining - if it isn't one of those that's frequently found oxidized even in asteroids. It's hard to say if it's going to be good enough in 50 years. The economy is complicated, and what seemed like a great venture might dissipate to a low-margin trade very quickly. The initial investment required is very large, and we don't *really* have the technology to do this right now - either for human-manned or robotic-based miners. Any attempts will probably come hand in hand with larger presence in space in general - that's where the real savings are. The main problem with mining asteroids is that they're pretty far from the Earth, and perhaps more importantly, from each other. If you happen upon the right kind of asteroid, you might be looking at hundreds of billions of dollars of worth. If you happen upon the boring kind, it might mean a few months spend looking for and travelling to the next one. Some sorts of automated probes would help, but again, we don't really have the tech now. Would it be plausible in 50 years? Possibly. There's some asteroids that are more accessible than the Moon's surface even. One typical mining candidate is [4660 Nereus](https://en.wikipedia.org/wiki/4660_Nereus) - it is thought to be magnesium rich, but it's mainly of interest because of it's approach-ability (if you time things right). It might serve as a pilot proof-of-concept operation sometime in the future, before we head on to the more distant belt. For story purposes, it might help to have some good reason why the initial investment got started. Something that *forces* people out of the well. There's relatively little interest in space exploration and exploitation among the public right now, and you could even imagine people fighting hard to prevent that (e.g. imagine you find the entire stock of gold on Earth in just one asteroid - that's not going to make gold-holders happy). How do you change that? Making people *want* things to happen is usually a good start. If people don't care about space economy (or worse, find it competitive to their own job), you won't get asteroid miners in 500 years :P [Answer] I'm going to go against the naysayers here and say yes. Economically speaking, the greatest cost to mining asteroids is the fact that there's no established pipeline. The assumption here is that every rocket must take off from earth, capture it's load and return to earth. With regards to the reduction in leaving atmosphere costs, there's always the approach of using a so called "space elevator" [A Nasa article with regards to that.](https://science.nasa.gov/science-news/science-at-nasa/2000/ast07sep_1) Once that's established, you'd need to establish a system of craft built specifically for floating through the asteroid belt. They wouldn't need to be that large as they wouldn't need to carry enough fuel to take off from anything with a real gravitational pull. With regards to the economics, the initial cost would have to be offset by large potential gains in the future. So the minerals pulled in would have to be incredibly scarce, or conversely, so incredibly cheap to pull down but be so incredibly abundant and be more so than on earth. Again, the second is a little more plausible if the established pipeline is already built and cheap to maintain. You wouldn't even need there to be an economically viable reason to establish the initial pipeline, just someone with disregards to econ. In "The Man in The High Castle" by P.Dick, his timeline allowed for the Nazi's to establish efficient rockets for international travel. His Logic for such a situation was that the Nazi's were mad with a craving for doing the unthinkable, regardless of the consequences to themselves in the end. [Here's a link to the scene where 2 characters are aboard the lufthansa Rocket](https://books.google.co.uk/books?id=5aBwki0xmZEC&pg=PA39&lpg=PA39&dq=Philip%20k%20dick%20man%20in%20the%20high%20castle%20lufthansa%20rocket&source=bl&ots=Rq1k7Oj5Y8&sig=DMvQ-qR6HxBUWHGbn-nPqVimeak&hl=en&sa=X&ved=0ahUKEwjGy5jk0YnaAhXKJlAKHRGNC_sQ6AEIYDAE#v=onepage&q=Philip%20k%20dick%20man%20in%20the%20high%20castle%20lufthansa%20rocket&f=false) Once anything is established and working, it doesn't need to prove it's theoretical worth to potential backers, as it's already generating visible wealth. If a madman in a dictatorship were to waste his resources on such a thing, You wouldn't have to worry about they why. If the profits of using such a system were to outweigh the costs of maintaining it, then it wouldn't be difficult to get potential investors for the continued use and expansion. It all ultimately boils down to how your timeline's constructed (50 Years is a long time) and how much you really want to mine asteroids. [Answer] Asteroid mining would be expensive, but the materials brought back would be worth it. Find a big enough asteroid and you can get tons of ore like iron, gold, platinum etc. I also suggest you automate the process using robots to do all the leg work. [Answer] It's the year 2068, humanity has managed to get a space elevator working about twenty years ago. Now, they need more metals and rare materials which are found in asteroids. Ships with specialized equipment bring asteroids towards Earth and set them in a very specific orbit, which passes close by the space elevator but does not collide with any other asteroids. Miners work on these asteroids and they get to work and deliver materials using the space elevator. A gigantic construction is underway to complete a self sustaining refinery so that asteroids can be mined **and** processed in place instead of having them brought to Earth. [Answer] So one thing that I didn't see anyone talking about is sure you get an asteroid, but how are you going to refine it. out in space there's no to low gravity, that means that even if you are able to heat metals to boiling, that you're not going to be able to pour them. They would need to be forced through some type of piston into workable shapes, ingots or what not that can then be tools and or rolled and compressed. This Piston type forge would have to be make of some material that could handle the heat and not get clogged by cooling metals, it would need to be easily repaired and replaced. ferrous metals could be manipulated by magnetism, but heated to molten, you find that magnets work differently on the metals. Sure it can be done on a no gravity environ, but the expense and process is going to be much more difficult. Extruded metals would be the easiest to process. If you had a large amount of dense mass you could actually create your own pseudo gravity well. But centrifugal force gravity is be far the cheapest, and could handle the things that gravity assists with such as pouring metals from crucibles. It just adds to the size of your operation(ship) though bringing a mass onboard a rotating ship also has it's issues. ]
[Question] [ Many people here have likely played [Spore](https://en.wikipedia.org/wiki/Spore_(2008_video_game)), a game where you design a species and expand its empire into space and beyond. It was one of those games that worldbuilders absolutely adored and after recently playing it I noticed something that could be interesting to see in *my* world. Spice Geysers; [![enter image description here](https://i.stack.imgur.com/NrGyv.png)](https://i.stack.imgur.com/NrGyv.png) To people who have not played the game, these geysers produce spice which acts as currency. What I'm wondering is, could these Spice Geysers exist in a realistic way? [Answer] My first thought, probably triggered by "spore", is to make them the vents of underground possibly burrowing fungal life forms. Something like the puffball mushroom family but giant sized. [![enter image description here](https://i.stack.imgur.com/SXZhw.jpg)](https://i.stack.imgur.com/SXZhw.jpg) They could periodically vent to spread their spores. If these spores had a useful property (my first thought is hallucinogenic drug) then they could easily be used as a trade good or currency. [Answer] ## Reality The closest Real life example I can give you for a spice geyser is any geyser that contains salt water. This isn't exactly a "spice" geyser as salt isn't technically a spice (its a seasoning). In addition, it would require a lot of refinement to get the salt ready for use. However, it would likely require about the same refinement as any other source of salt derived from salt water. As far as use for currency, [salt was used as a currency](https://en.wikipedia.org/wiki/Salt#History) and highly valued commodity for many years, but that might not be exactly what you are looking for. 1. Salt is not technically a spice, but is a seasoning (close enough) 2. [Salt water geysers exist](http://mysite.du.edu/%7Ejcalvert/geol/geyser.htm) 3. Salt was an extremely valuable commodity, and [was used as a currency](https://en.wikipedia.org/wiki/Salt#History) ## Fiction and Previous Worldbuilding When I think of spice as a currency, one thing jumps directly mind. This is the spice Melange, from the classic novel Dune. Dune is a seminal sci-fi book, and should be instantly recognizable to any fan of fictional literature. The book revolves around conflict over the spice Melange. Melange grants a great many boons to its users (as a drug) and can be found on only one planet, Arrakis. Spice almost certainly acts as currency in Dune, and is highly coveted by all, to the point where it is said that a [one briefcase full of spice would be enough to purchase an entire planet.](http://dune.wikia.com/wiki/Spice_Melange) More specific to your "Spice Geysers", there is a [phenomenon in the dune universe called a spice blow](https://en.wikipedia.org/wiki/Sandworm_(Dune)#Connection_to_the_spice) that would appear to observers much like a geyser. 1. Melange is a spice 2. Melange can form a geyser-like plume 3. Melange is an extremely valuable commodity, and could be (was?) used as currency @superluminary 's answer is actually somewhat related to mine. The Author of Dune, Frank Herbert explicitly identified CHOAM with OPEC, equating the spice melange to oil in an interview with OMNI magazine. Edit: Artist's Rendering of a Spice Blow [![enter image description here](https://i.stack.imgur.com/M6HXy.jpg)](https://i.stack.imgur.com/M6HXy.jpg) [Answer] ## Oil The definition of a spice is: > > an aromatic or pungent vegetable substance used to flavour food, e.g. cloves, pepper, or cumin. > > > It is a biological material, that can be used to impart flavour to food. So we might ask, what biological material do we see gushing out of the ground in our world? One solution might be oil. On Earth, the ultimate breakdown product of sea animals and plants is crude oil and natural gas. Crude oil is a complicated cocktail of hydrocarbons, which can be refined into petrol, diesel, lubricating oil, and other carbon-based substances. Imagine if the breakdown product of dead sea life were palatable. Wine and Cheese improve with age (up to a point). The Chinese eat "100-year-old eggs". We can then postulate a planet with spice pools instead of tar pits, and spice gushers instead of oil. [Answer] If you replace "spice" with any valuable material, simply for the fact that those are needed for something and it's easier to extract from natural occuring geysers than importing them from other worlds... Check for eruptions on [Io](https://en.wikipedia.org/wiki/Io_(moon)) (sulfur, an important component for metabollism of anything organic, and you can also make some salts with that) and [Triton](https://en.wikipedia.org/wiki/Triton_(moon)) (nitrogen, you can make laughing gas or an Earth-like atmosphere for a ship with enough of that) (also actual geysers, more tame than Io's volcanoes). In fact, thinking back about Io... If that sulfur is bound to any metal in any form, it should taste salty, maybe spicy... For the very definition I know for a chemical salt is the ionic binding between a metal and a non-metal. I don't recommend trying any of those salts in your diet, though. [Answer] There are bacteria that live near volcano and deep sea vents that feed off the heat similar to how surface plants feed off of light. Geysers are just hot springs that build up pressure. It's potentially possible that some deep-sea-vent bacteria that produced some desirable spice could adapt to living near geysers. Then their produced spices could seep into the ground (and thus into the water of the geyser), and the spice is harvested from water rather than risking damaging the ground the bacteria are in. ]
[Question] [ When viewed from their planet, are moons always the same colour as ours? Or is there a variation? What other colours might be possible and what causes the differences in colour? [Answer] More or less they can be of any colour. The colour of the moon from the point of view of someone who is in the planet is determined by four factors: The moon material, the atmospheric composition, the sun colour and the observers eye sensibility. * First the colour of the sun, normally determined by the temperature. You probably want it to be white/yellow or white/xxx so it doesn't change the planet light. * The moon material will be the thing you can change more as you can choose many materials with different colour reflections. For example iron oxide for red (like Mars). * The atmospheric colour is the final filter, so you can have a brown moon and if you have a green atmosphere, the moon will be more green than brown. The colour of an atmosphere can be because of its components in different layers so maybe you can have a coloured sky but still have a breathable atmosphere in lower level. * The sensibility of the observers eye can also filter what it perceive. Humans can see a range of frequencies that we call "visible range", but other animals can have other ranges for example bees can see in ultraviolet range. This can be affected by the sun light as it's normal for life to evolve to be more sensible to the range of light it have. So you can combine each of the three factors to create the colour you want. About the colour of the moon, you can search for mineral pigments to found many pigments (colours for your moon) that are more or less naturals. For example you have: lapus lazuli for blue, iron oxides for red / ochre even green (see <http://www.earthpigments.com/sof-green-pigment/>). I found a page in which you can find minerals by colors: <http://webmineral.com/help/Color.shtml> You can see a link about what animals see in following link <http://www.colormatters.com/color-matters-for-kids/how-animals-see-color>. [Answer] Of course no. A satellite colour is the combination of 1. the colour of incident light (depends on the star) 2. albedo colour parameters (depends on the material of the satellite itself) 3. atmospheric filtering. Since there are blue, white, yellow, orange and red stars, that's a lot of possibilities. With only our own Sun (orange), and no atmospheric filtering (since these photos are from space), we have these: ![Moons image](https://i.stack.imgur.com/Hb6Yg.jpg) (Source: <https://commons.wikimedia.org/wiki/File:Moons_of_solar_system_v7.jpg> , Original source: solarsystem.nasa.gov , more details in original page) [Answer] I'd think much variation. Our moon is a pretty barren rock with some lava flow colouring it (lava flow is the dark spots. The other side of the moon mostly lacks this and appears much more solid white apparently). a couple examples: IO (moon of jupiter), would appear very yellow in the sky due to it's sulhpur composition. Europa (another jupiter moon) is mostly ice and it's colour would be more white along with a red center. Triton (Neptune) has a nitrogen atmosphere and will have a blueish colour Tethys (saturn) has a yellow / sand colour to it. A good portion of moons will look barren as ours, but there can easily be colour variations from simple make-up. Most of these pics can be readily found on google. ]
[Question] [ It's well understood that [torchships](http://www.projectrho.com/public_html/rocket/torchships.php) are the most powerful spaceships that we know of without inventing new physics or handwavium. Getting around on the back of a nuclear flame is crazy fast. Also, attacking something with a nuclear flame is a no-brainer since that much energy in a directed fashion will melt through the thickest tungsten armor with ease. But, what about when something is attacking the hot end of the torchship? **How effective is the nuclear flame at defeating any and all kinds of attacks?** Attack types under consideration: * Beam: All Types and wave lengths * Projectile: Kinetic * Explosive: Chemical, nuclear and anti-matter Torchship Specs: * Magnetic bottle containment * Continuous thrust * 4.5 Tera watt drive output * Wet Mass: 1,000,000 kg * Dry Mass: 500,000 kg * Exhaust Velocity: 3,000,000 m/s * [$\Delta$V](https://en.wikipedia.org/wiki/Delta-v) : 2,000,000 m/s * Thrust: 290,000 N (Ship specs shamelessly stolen from Project Rho. Credit where credit is due.) Out of scope: * Any attack that doesn't have to go through the drive system. I know that attacking a torchship from any other angle will render it the same as any other spaceship; I'm not interested in that. [Answer] ## You aren't as safe as you think ### Other properties of the ship The combustion chamber need not be made of any sort of imagined material. Conditions in today's rocket nozzles readily exceed the material properties of the nozzle, so [measures](https://ocw.mit.edu/courses/aeronautics-and-astronautics/16-50-introduction-to-propulsion-systems-spring-2012/lecture-notes/MIT16_50S12_lec14.pdf) are taken to protect them. Cooling is the biggest, some use the cryogenic fuels through the nozzles as a preheat, others use a stream of fuel to form a layer between the combustion and the nozzle. The same could be done with the nuclear fire of a torch ship. The plasma in a test [fusion reactor](https://en.wikipedia.org/wiki/Tokamak_Fusion_Test_Reactor) is contained in powerful magnetic fields and kept away from the walls of the container. The same could be done with the torch ship, stand off the reaction from the walls of the chamber, add some radiation shielding and a cooling system and you are all set. ### Beam Weapons (To include directed energy) A beam of charged particles could easily wreak havoc on the nuclear reaction, admittedly it would be challenging to ram through the exhaust stream, but focused enough and it could get through. Adding [alpha partilces](https://en.wikipedia.org/wiki/Alpha_particle) to a fusion reaction could snuff it out or cause a runaway reaction. [Beta Particles](https://en.wikipedia.org/wiki/Beta_particle) could cause issues as well by changing the charge of the plasma. The effectiveness of this depends on the magnitude of the magnetic containment and its polarization. A beam of [neutrons](https://en.wikipedia.org/wiki/Neutron) could also cause issues, interfering with the reaction and adding a ton of extra energy to the chamber as they decay. [Heavier Ions](https://en.wikipedia.org/wiki/Relativistic_Heavy_Ion_Collider) will also interfere with the reaction and do physical damage to the containment chamber. Pick your [wavlength](https://en.wikipedia.org/wiki/Electromagnetic_spectrum) of the laser, and dump plenty of power into it. Depending on the content of the reaction some wavelengths may pass right through it and damage the walls of containment. I'm thinking [gamma radion](https://en.wikipedia.org/wiki/Gamma_ray) of a magnitude that exceeds the design of the torch ship. Likewise, some wavelengths may be absorbed by the reaction and exceed the design of the ship, I'd guess [microwaves](https://en.wikipedia.org/wiki/Microwave). **Results may vary, ask your lead engineer if you have questions** ### Kenetic Weapons [Relevant XKCD Comic](https://what-if.xkcd.com/16/). Moving fast enough and your kinetic projectile will be unaffected by the nuclear fire. If the contact with the heat is brief then the projectile won't have time to vaporize/ablate away. **I'll see if I can apply some thermodynamics to it later on**. Also, even if you manage to vaporize it, now you've got a cloud of vapor with the energy of the projectile moving towards you. ### Explosives Getting them into the chamber is the main issue. Get through the exhaust stream and your payload will do its job. [Answer] There's a monumental difference between an uncontrolled nuclear explosion and harnessing one for long term propulsion. Controlling such fires is tricky. It's even trickier when some sick fool decided to take an even faster torchship and ram it up into your exhaust! The fool will certainly not survive the process, but now you have a complicated situation. Your beautifully controlled carefully balance propulsion system now has another nuclear propulsion system crammed up inside it. And, as you melt it with your nuclear fire, it starts to behave less and less like a torchship, and more and more like a nuclear bomb wedged in your tailpipe. Anything that was balanced is now decidedly unbalanced. You really want that part balanced. And as Munroe [put it](https://xkcd.com/1133/) regarding the exhaust end of your spacecraft, "This end should point toward the ground if you want to go to space. If it starts pointing towards space, you are having a bad problem and you will not go to space today." [Answer] Any drive system is about control. A torchship flies on a continuous controlled nuclear reaction. Probably the simplest way to destroy it is to cut through that control, fire a significant load of fissile material up the pipe contained in such a way as to explode within the constrained area. Pour too much fuel on the fire. As for how to protect your missile on the way in, use same method as the drive itself is contained within the ship. Anything that can protect the ship against its own drive can protect an incoming missile against the drive. Part two is about balancing the missile drive against the returning force of the ship drive to get it inside but that's a solvable problem. [Answer] You're talking about an engine that is outputting 4.5 Terawatts, in a controlled fashion, **continuously**. That's a 14th of the energy of the atomic bomb dropped over Hiroshima every second. A lightning bolt peaks at around 1 Terawatt, but only lasts for 30 microseconds. I'm pretty sure anything you throw at the hot part of that won't even register when compared what it has been designed to contain. In the case of a projectile or explosive it's going to be destroyed long before it gets within range to become dangerous. If it's a laser unless you're using a terawatt laser it's not going to make a difference. That's going to require about a thousand nuclear power plants running continuously to power it. [Answer] I here propose two exotic type attacks which could go through the nuclear torch and hurt the torch ship. These are suitable only for concept-driven science fiction. **Dark matter fusion poison.** I take "torchship" to mean a fusion powered rocket: mass is converted to energy. Dark matter is unaffected by electromagnetic radiation and so a clump of dark matter should be able to traverse the energetic output of the fusion engine. Does dark matter pack a wallop? Would I feel a lump of dark matter dropped on my toe? I cannot find the answer. Maybe dark matter moves right through normal matter. I read that as far as is known, dark matter cares about gravity and the weak force. But the cool thing for the torchship (and a scifi endeavor) would be a wad of dark matter interfering with the fusion engine. [The weak force mediates fusion reactions](http://oilprice.com/Alternative-Energy/Nuclear-Power/Scientists-must-Study-the-Nuclear-Weak-Force-to-Better-Understand-LENR.html). A cannonball of dark particles traversing normal matter and then interfering with fusion via the weak force could poison the reaction. This would be cool in that the result of a successful hit would be that the engine would turn off. Or the people who can shoot the cannonball might not be sure what it will do, and they shoot it anyway. Other outcomes are possible. How to fire a cannonball made of dark matter? Gravity gun? **Gravity waves.** These too should be impervious to the output of the engine and just about everything else. The prospect of generating on demand gravity waves seems daunting but if you can make them (maybe converting one type of electromagnetic radiation into another?) they obey the rules governing other types of EMR. They have energy and can do work, which means to me that their energy should be attenuated when they do work. Could you concentrate them with a lens? In any case: gravity waves can travel up the exhaust. So what if they do? I could imagine that a wave which strongly reduced the distance between particles would accelerate interactions between those particles. Just like flammable vapors under pressure explode more violently, I could imagine that a fusible substrate suddenly compressed would undergo fusion more violently. Conversely, interacting particles suddenly at a distance from each other might reduce their interaction or cease to interact. Gravity waves this strong might also have local effects on time. Again this would be a fun thing to explore in the writing: the people who can fire gravity waves as a weapon might hope to blow up the torch ship but other things might happen as well. [Answer] A magnetic field can mess up the torch containment and cause the engine to wreck itself. So an explosion that’s designed to produce a momentary, incredibly strong, magnetic field could be a weapon. Free neutrons are very penetrating because they don’t “feel” the electrons as solid barriers like other atoms would, and the nuclei are very tiny targets. A beam of neutrons fired up into the rocket will pass through the plume with high efficiency. Then those that gets through will [bombard the rocket mechanism](https://en.wikipedia.org/wiki/Neutron_radiation#Effects_on_materials), transmuting elements and damaging it. Or, just the energy released as some of them decay in proximity of the engine parts will cause damage. Consider a tight beam or dense pellet of antimatter. The rocket exhaust is tenuous, not solid, so only a small part of the antimatter will erode from the passage. [Answer] Since torch drives are made of unobtanium, a sufficient number of unobtanium KE penetrators of sufficient size and velocity, aimed at the drive's thrust chamber, could damage the drive causing explosion. EDIT: unobtanium has the amazing property of being as strong and temperature resistant as I want it to be. Thus, since it's easier to break things than to build them, unobtanium KE penetrators would **naturally** be able to break torchships. ]
[Question] [ In this universe, mass and gravity work differently so stable torus planets are possible (donut shaped). How would a torus world orbiting a single star have to rotate in order to have a stable day and night cycle on all of its regions? For example if it was constantly in a horizontal position from its star and rotated as such, the inside of the ring would be eternally dark. So I believe its rotation would likely have to be both horizontal, vertical and complex so that all its regions would have similar constant day and night cycles. Assume this torus world has a total surface area similar to Earth's, a similar distance from its sun, 12 hour days and nights, etc, etc. (If that information is necessary for any reason.) [Answer] # A Day/Night Cycle for All Points 1. Lay the torus down so it's in line with the plane of its orbit. (That is, it's "laid flat".) 2. The planet must rotate about an axis that is perpendicular to it's orbit, like [Uranus](https://en.wikipedia.org/wiki/Uranus#Orbit_and_rotation). 3. The planet must also rotate such that it's axis of rotation is always perpendicular to the orbit, like a [tidally locked planet](https://en.wikipedia.org/wiki/Tidal_locking). So yes, the planet is rotating about two axes, but one of them is rotating much more slowly than the other. There is also the oddity that people on this inside will have "short nights" and "long nights," because the sun will be blocked by the far side of the planet (a short night) and then because the sun goes under their horizon (a long night). People on the outside of the ring will just have long nights. So the duration of a night will change based off of geographic position, but the duration of those night(s) will be consistent. This will also result in 4 points which are in perpetual twilight, almost like the earth's poles in their summer. I suggest calling them the twilight lands. [Answer] # Spin it like a top [![enter image description here](https://i.stack.imgur.com/J8YTh.png)](https://i.stack.imgur.com/J8YTh.png) If you set it on its side so that one could see the sun through the hole in the middle from an orbit further out. then spin it around that axis, You'll have a day/night cycle similar to earth's. The outside will be normal, and the inside will have eclipses in the middle of each day. Edit: Now that I think about it some more, the inside will spend most of their time in twilight. Either from the eclipse, or from all the light reflecting back at them from the ground "above" them. [Answer] I'll admit it. You nerd-sniped me on this one. I had to figure out what the day night-cycle on a toroidal planet was like. It happens to be that mapping a torus to a map is really easy, so after setting up a simple script in Blender3D, I was good to go. For reference, the top and bottom of the animated image is the smallest possible circle in the torus: ie the inside circle/edge. First up, some axis (taken from some other website): [![Torus with Z along it's vertical axis when laying flat](https://i.stack.imgur.com/MgeUa.gif)](https://i.stack.imgur.com/MgeUa.gif) First up, spinning on the Z axis while the sun points at it from the side: [![Dot moves across the screen](https://i.stack.imgur.com/k8rC7.gif)](https://i.stack.imgur.com/k8rC7.gif) As you expect, we get a patch of brightness (the side facing the sun) while the rest of the planet is either facing away from the sun or shaded by the center. How about we rotate it by 90 degrees so now the Z axis starts facing the sun and rotate it around the X axis (As per amflares answer): [![Spinning Torus](https://i.stack.imgur.com/JJhka.gif)](https://i.stack.imgur.com/JJhka.gif)[![ describe this....](https://i.stack.imgur.com/KHTFl.gif)](https://i.stack.imgur.com/KHTFl.gif) Wow! That's fancy. The day and night goes in opposite directions depending on where you are. And that's not inside vs outside either (remember, inside is the top and bottom edge). You'll notice it creates a line twice a day. That's when it is 'face' on to the sun (sun is on the Z axis). You could live in that - the whole planet get's illuminated at some point during the day - but I have no idea how timezones will work. I feel that something would be pretty messed up here. So let's try another tack. Rather than spin it along directly along an axis, let's give it a 45 degree tilt: [![Spinning at 45 degrees](https://i.stack.imgur.com/RIExZ.gif)](https://i.stack.imgur.com/RIExZ.gif) [![Still no idea](https://i.stack.imgur.com/mlL53.gif)](https://i.stack.imgur.com/mlL53.gif) Aww. That's even more messed up. Right, I'm out of ideas for how your planet should spin. I'd say go for the "spinning it like a top" - ie not around the hole. [Answer] Orbiting a sun that is far away is always valid like amflare has stated but it is limiting. But if you are messing with physics, there's a few fun things you could do. Especially if the "sun" travels around the planet. * The sun oscillates up and down shooting through the center of the torus. This would leave a cold outer edge and an always lit inner edge. You'd also have North Days and South Days. * The sun (or suns) draw a helix or screw pattern as they loop in and out of the "hole" and also travelling around the circumference of the donut. The inner side would always be lit some amount each day though changing with seasons but the outside would have dark seasons. * Skip a spherical sun completely and go with a varying size torus of heated plasma that goes up through the middle (while small) and travels around the outside (as a larger ring) before getting smaller to fit inside again. People on the outer edge would only see an arc of light sweep across the sky, the rest would see a ring. If planets have a stable shape as tori, suns might also follow the same pattern. [Answer] This is a totally different suggestion but if you are messing with physics anyway.... Have the sun stationary in the center of an enormous torus and then rotate along the internal axis of the torus. It would rotate in a way that the outer edge would become the inner edge during the day. Unless you handwave a lot of stuff through magic, landmasses would get closer together during the day and farther apart during the night. Because the outer circumference is larger than the inner. This kind of world can only exist in a universe of magic or a universe with a super science race that has a really odd sense of humor. [Answer] I think you are mistaken about what is referred to as a "ringworld". Ringworlds are generally not torus (donut) shaped worlds that rotate on one axis and orbit on a different axis. Ringworlds generally are rings around a star, with an internal radius equal to the orbital distance. As such, they only need to rotate in one manner (about the star's center of gravity). Day and night cycles are usually created by a smaller ring of alternating transparent and opaque segments that orbits inside the main ringworld at a faster pace. If you're imagining a torus orbiting a star not at its center, it would also have to rotate along the axis tangential to the orbit in order to permit light to reach the far side of the ring. This axis would constantly be moving as the torus rotated about its own center of gravity to create the forces necessary to simulate gravity. Edit: Thinking more about this second case, you could tilt the ringworld enough to let light hit the far side of the ring, then [tidally lock](https://en.wikipedia.org/wiki/Tidal_locking) the ringworld to the sun. Day/night cycles would come naturally by way of the ringworld rotating about its CG. ]
[Question] [ The hero of my story has been cursed to be forever 'bloodthirsty' in the literal sense of the word. Effectively, he has been turned into a vampire. But drinking blood will cause him to lose his senses, compassion, and empathy, which is why he refuses to drink blood, even though his body thirsts for it and causes him burning pain when he smells it. However, he still gains nourishment from normal food. Thus, how would I reconcile the fact that hunger, thirst and need for sustenance can be sated by normal food and drink, and yet he still thirsts for blood? Would drinking blood cure him of the need for normal food? Can he live solely on blood? Could drinking blood increase his strength beyond what normal means could? [Answer] ## Consuming blood can be a psychological addiction instead of a physical need It doesn't have to be a physical dependency. If he can live indefinitely on normal human food, then he's getting everything his body needs in terms of carbs, fats, proteins, vitamins and minerals. However, just because the body has what it needs, doesn't mean that the psyche has what *it* needs. The burning sensation in his body could be the result of a projection of his mind. His body is actually just fine, but his mind thinks his body is on fire. We see this kind of projection in some forms of mental illness where a patient will believe their skin is dirty but in reality they've "cleaned" their skin so much that the skin is gone. In addition to this being a purely psychological problem, this poor vampire is in a state similar to ["dry drunkenness"](http://alcoholrehab.com/addiction-recovery/white-knuckle-sobriety/) or "white knuckling", a state familiar to anyone with alcoholism. He's given up blood [alcohol] but his mind desperately, desperately wants it. Extraordinary feats of will-power keep this vampire from taking that first juicy bite. The inevitable problem with dry drunks is that they start drinking again. In the context of this story, this vampire is in a desperate "man vs self" style conflict....which could get really interesting. [Answer] Well a normal human can live a long time on bread and water. However, they aren't going to be very healthy. I would say that the normal food is sufficient or barely adequate to sustain him (as a vampire). A rare steak might help him out a little more, or blood sausage. I would expect that the constant need for blood is either a curse that tortures him or that consuming blood powers some of his supernatural abilities. When he does drink blood it may also give some kind of high like heroin, making it harder to resist. [Answer] In answer to your questions about living on blood and getting extra strength from it, the answer is categorically no on both. Blood has a lot of nice vitamins which are handy for long-term health, but it's totally lacking in calories. A vampire living solely on blood would die of starvation, and in about the same time as a regular person would starve to death. Even if you hypothesise a different digestive system, it still doesn't work. There simply isn't enough chemical energy in there to be extracted. That also kind of screws up the extra strength option too. Of course hysterical/berserker strength is a thing, so some kind of brainwashing to tap into that when exposed to blood might be possible. But that's just accessing strength they already have and don't use. And of course you could invoke magic. Vampires drink blood because of narrative necessity (otherwise you wouldn't have a vampire in your story!) and magic can provide enough handwavy depolarise-the-positronic-fields-Scotty guff for temporary suspension of disbelief. [Answer] You could make it so that blood is simply a craving. A lot of people crave sugar and fatty foods despite the fact that they offer little nutritional benefit and have lots of downsides, yet people still eat plenty of them and it makes them overweight and causes plenty of issues such as type 2 diabetes. Sugar does actually provide energy in moderate quantities, and gorging on plenty at once can make one hyperactive. Having absolutely no sugar in a diet can equally cause problems, or mean that the person has little energy. So substitute sugar or fats for blood and it's a similar scenario. Maybe lack of blood would make the vampire lack certain things, they may become some form of malnourished without blood, or are affected more by sunlight, but can still survive reasonably well. If they moderate their blood intake then they can be completely healthy, but when they drink blood they will obviously crave more, which can soon cause them to get out of hand and they become addicted to it. Then an excess in drinking blood, rather than making them overweight would cause them to have less humanity and morality. Maybe certain vampires have no blood in order to ensure their systems are not used to it, then they have parties where they gorge on blood and temporarily become incredibly energetic/strong/nigh-immortal. There are people who exist almost solely on sugar and fatty foods, and whilst they are not particularly healthy they can continue to survive for a long time. So perhaps a vampire can exist solely on blood, but again it causes a number of issues. [Answer] A good model here might be human corn eaters. A lot of (most?) people consider corn quite tasty, and eating enough of it will make you feel full. However, a person physically cannot live on nothing but corn. It is deficient in two important nutrients, lysine and tryptophan, that the human body requires to process protein and build bones. Trying to do so causes a protein deficiency condition called [Kwashiorkor](https://en.wikipedia.org/wiki/Kwashiorkor), where people get bloated stomachs, large livers, red hair, and will eventually die. This is why historically societies that relied on corn (eg: Mesoamerica) also had to cultivate beans or some other source food for those missing nutrients. So for your putative creature, all you'd have to do is change his physiology in a way such that there's a nutrient required for survival that his body is geared to only process out of blood. One candidate might be [Albumin](https://en.wikipedia.org/wiki/Albumin). Its the primary protein in blood, and is usually produced by the liver. So a liver that for some reason quit producing Albumin, or one of several conditions that can cause it to get [removed from the body too fast](https://en.wikipedia.org/wiki/Protein_losing_enteropathy), could be your mechanism. A list of [typical symptoms is here](http://emedicine.medscape.com/article/166724-clinical#b4). Interestingly, hypothermia is one of them, as are a lot of physical changes that might make a person look ancient. ]
[Question] [ So, this race of Wussname are a peaceful people. Each and everyone of them possess this weird ability of sympathy that allows them synchronize their emotions and share their knowledge with other each within a short range of a hundred meters or so. Their warriors are not as numerous as mine. At their best, I still outnumber them four to one. Their physical prowess and weaponry are about the same as mine. But, somehow, they have effectively refused to submit and resisted my forces. The thing is, I have never wanted to conquer them. I only like to claim those rich mines of Unobtainium deep inside their territory. And the idiots refused all attempts at negotiation, bribery or infiltration. And they called me evil while I only want those resources to build more advanced armies and plunder other countries. So, how would I effectively destroy these people. I would prefer keeping them alive to torture them later, but extermination is fine too. Notes: My army consists of mostly medieval infantry, about a tenth is cavalry, a tenth have cannons. I also have a hundred of Dragon knights but they are expensive and I would prefer to keep them for another day, since I heard there is another country that have a lot of flying fighting bird thingies. **Edit1**: My army outnumbers them, but but their warriors are significantly more skilled since they can share fighting knowledge and experience. I estimated that one of them could potentially kill 2.7 of mine. But I don't want to mobilize all of mine just to kill them, because there are bigger Bads behind my back. I need to defend my border too. Since the beginning, they refused all my attempts at infiltration covert or not (they can spot my spies right away). They said out right that 'NO deals with the Devil!' Half of my vanguard are torturers, killing and torturing as they go. What they do, even I feel it creepy sometimes, and yet it did not break the psychic freaks. It enraged them further, boosted their damage. Beside, the reports said they have squads of specialized healers to soothe the warriors and correct the minds of broken men I released. **Edit 2**: Since everybody seem to forget that the enemy is smart and have a lot of advantages over my forces. I'll list all the reasons (I can think of) of why was it so hard to kill them. 1. Near instant message relay. 2. Perfect battle coordination. Imagine there is a mind sitting behind a screen called "computer" stopping time to arrange troops in perfect position. 3. Perfect group cooperation. Deadly in back-to-back fighting. 4. Individual combat mastery, one of their warriors equals 2.7 (only estimation could be more). Consider all of them are veterans. 5. No negotiation. Can spot spy or assassin right away. 6. Have psychic healers to drive battle moods in any way, it's safe to assume that they're always in the right mental state to shatter armies. 7. Their uniforms look so weird you can't tell who their officers are, not sure if they need one. 8. Psychic range is about 100 meters. Putting a wall between them would not stop it. 9. They're are peaceful, they resent killing but have nothing against severing an arm or leg and leave you bleeding. 10. My country faces four nations with Wussname to the north, all the other neighboring countries are enemies we are constantly engaged in wars. 11. I have a truce with Whatcha to the west, promised to give them 20% loot. It means I'm currently using only half of my numbers actively fighting Wussname. It takes 2 weeks with double horses to ride across my country. Marching is slower. I don't like to mobilize all my troops unless I have a good reason to do so. 12. Their General is as good as any commander who has survived 30 years of continuous warfare, and is good at winning wars. 13. No idea where their weapons come from, but it is as good as mine. Same level of technology (medieval). 14. Known practical weapons: Bow, cross bow, cannon (powerful but expensive and ammunition are slow in production), lancers, steel swords, pikes and stuff. Dragons are for quick hits or special operations only. Armors is mostly leather and anything anyone can buy, it's hard to fully equip 750,000 men with steel. [Answer] Using the right tactical approach, this shouldn't be much of a problem, if you are superior to them in numbers and military supplies. **Method 1** Attack them on 3 sides at once! You are dividing their already-less-than-half forces into three. Now, here is the trick. You attack them with 1/6th of your entire force from three sides. (Hence you are using half of your total military). All three assaulting parties are of equal force right now. The defenders would quickly form 3 groups to counter the threat and they will probably make a quick mincemeat of them soon but ... After dividing their force into three, assault them from the fourth side from the remaining half of your army. Before the little naive fools regroup, your forces should be rolling their leaders under their boots in the capital! **Method 2** Use guerrilla tactics. Plant landmines on the border at night. Then in the daytime, initiate a border skirmish and entice their troopies to cross the border right where the landmines are present ... I don't think their hive-mind ability is going to help them locate the mines. Rinse and repeat. Repeat and rise. At times you are going to plant landmines and play on enticing them to cross the border. Other times you are going to NOT lay the landmines, give them the impression that they are in place, then initiate a skirmish, kill a few and quickly return. Rinse and repeat. **Method 3** Use biological weapons! Infect some of the prisoners with a deadly contagious pathogen (that shows its effect later) and set them free. The healers won't know anything is wrong... until the pathogen has spread all over in their population. Now you simply go trampling them under your boots... [Answer] **Physical Death** If you outnumber them four to one, just walk in and do whatever you want. Unless there's some kind of brilliant victory by General Wussname, you'll be able to just roll over them. Even if they manage to kill 2 of your troops for everyone one of theirs, you still have double the required troops to annihilate their army. Unobtainium, obtained. **Psychic Death** Capture a good number of the Wussname and take them back to your dungeons. Torture them into insanity or force them to watch untold pain and atrocities. In modern language, give them a raging case of Post Traumatic Stress Syndrome. Release them back to the general Wussname populace and wait for the nightly screams to begin. Experiences like torture will come back in dreams which are then shared across all the Wussnames. Some (many) won't be able to handle the stress or images shared and either go insane themselves or kill themselves to make the images stop. If you can offer them some kind of cure (it doesn't need to work, they just need to believe you have one) then you have an incredibly powerful bargaining chip. Unobtainium, obtained. [Answer] The question states that "their warriors are significantly more skilled since they could share fighting experience. I estimated that one of them could potentially kill 2.7 of mine.". However in battle I'm not sure that would actually work to their advantage. One battle has joined, a psychic range of 100 meters will mean that hundreds or possibly thousands of fellow psychics are all fighting at the same time and all sharing their own feelings and emotions. That mix of rage and fear, and many emotions in-between, will be enormously distracting. Once the forces are engaged in melee combat, each man is effectively fighting one or maybe two men in front of him. To do that well takes concentration and awareness. Having hundreds of other peoples emotions washing over you (especially if they're wounded or dying) is not the sort of thing that aids concentration. Fear is a very powerful, deep-rooted emotion. There's the very real risk that a localised panic, caused by a unit being overrun or surrounded, spreads quickly across the whole army. Suddenly, the psychics could find their whole army being routed simply because of a handful of men being overwhelmed. [Answer] ## How evil are you ? Genocide can be a hassle, as the population is rarely cooperative, and the gains are never enough to cover the expenses of such vast project. Fortunately, the human cruelty is nearly infinite, and this hasn't stopped many powerful leaders and sharp mind to spend countless time and effort on such a despicable purpose. Here is a list of useful tactics that have been used through history, or that have been invented by that wicked mind of mine. You can use them both for genocide or to simply break them as a people. ## Disease : As mentioned by Youstay Igo, you could find some sickness they are vulnerable to, and use it against them. You have many ways to do this * infect some prisoners and then let them escape from your prison. * hold a position upstream of a river were they usually drink, and throw all sorts of nasty things in it, like the feces of a hundred thousand soldiers. * sell them some infected clothes or covers, and watch smallpox do the job. * drop dead bodies on them with your dragons. With some luck you may even hit some wells in the process. ## Scorched earth Ravage any land you can get hold on, and leave nothing behind. Each one of your defeat will only buy them some time. Each one of your victory will cost them people and land, crippling their economy and morale. Burn the villages, rase the cities, salt the earth, poison the wells, kill the men and enslave the rest ; this may even help you fund this war. ## Psychological warfare This one has been mentioned by many other answer, so I won't detail it. Even if torturing some prisoners is not that effective against the rest of the population, this cannot make them any good, so carry on. It could even be used as a distraction to boost your own troops moral. ## Debilitating Drugs In the [opium wars](https://en.wikipedia.org/wiki/Opium_Wars), Chinese forces were significantly weakened by the use of opiods, which were illegally imported from British colonies (this was, as you can guess, the starting point of the war). Getting Wussname to widely use some sort of addictive drug may reveal tricky, but very useful once you succeed. You may achieve this by using some third party, so they do not suspect the provenance of the drug : manipulate a travelling merchant, a friendly country of your enemy, or send troops equipped with the drug to a suicide assault. They may found the drug on your soldiers body and try it. ## Toxic gas You may have some alchemist guild to help you on this. Find some stone that produce a nasty gas when mixed with water and other stones, use the right wind at the right place and bam, you got a tactical and psychological edge on this annoying race of them. ## Guerrilla warfare Youstay Igo mentioned that too. Ambush, traps, landmine and gunpowder are your friends on this one. Use also your dragons to make raids on their cities with incendiary bombs. Beware thought, as this is their country, they know it better than you do. I'd suggest you burn forests rather than trying to use them for an ambush that could be easily scouted and used against you. ## Aftermath Once you are done with all that nasty stuff, you can track the survivors, capture them, break them, drug them, breed them, and use them to transmit messages for your future battles. Find some way to let them hope for freedom, like a prophecy about a white knight in shining armor, so they have something to lose if they betray you. EDIT : I almost forgot, but this will also grant you the unobtainium. But you may discover that having some instantaneous communication is far more precious than better weaponry. Also, [as Conan said](https://www.youtube.com/watch?v=6PQ6335puOc), there is nothing in life better than crushing your enemy. [Answer] It seems your foe's advantage lies in the shared years of psychic knowledge of fighting. But this knowledge will be useless if the style of fighting changes drastically. Being a brilliant swordsman doesn't teach you how to shoot a musket. Change the style of battle and remove their advantage. If they usually fight against close packed formations spread out, if they usually fight in clearings fight in forests, if they usually fight during the day fight at night. If they normally fight swordsmen bring in longbows. PS. Cannons annihilate normal medieval tactics. If you have field cannon when enemies attack with tight formations blast them with grape shot see pickets charge or any of Napoleon's battles. Good cannon are why trench warfare happened. The first part of the answer assumed your cannon were no more effective than archers [Answer] I don't know what the terrain is like but since you're so evil why don't you just [burn them out](https://en.wikipedia.org/wiki/Scorched_earth)? You can start fires across the front and burn everything that can burn to the ground. You don't even need real soldiers for this. A couple soldiers can supervise a group of slaves, so your manpower increases dramatically. Try not to engage the enemy and just start lots of fires everywhere. Keep doing this as you move through the countryside and pretty soon the psychics are all starving. I would think your dragons would be especially helpful with this if they are the fire breathing variety. This will force them to spread out their troops, and let you ambush them with overwhelming numbers. Eventually the natives will counter attack you and you can perform a tactical retreat to a place where you can fight them off effectively or lead them into a trap where you drown them in a flash flood, crush them in a rock slide, etc. Regardless you just keep burning everything until there is a charred, barren, wasteland progressively expanding into their territory. Keep reminding them at every opportunity all you want is a modest amount of stuff from the mine. Eventually they'll crack after enough bad winters with progressively diminishing food. By then the full output of the mine will seem like a modest amount as long as they can eat. Of course you should periodically burn down a few villages so their somewhat fuller bellies don't breed any rebellious ideas... [Answer] Many armies have Buglers and Drummers to sound maneuvers. You can use the wailing of torture victims! Since the send/receive telepathy of these guys is really on shared within their own race, you need them broadcasting the most horrific stuff during a battle. Step one, capture some. You need about 1 captured for every 75 or so enemy Maybe threaten or cajole them while you have them, but don't harm them until battle day. On battle day get them up and out on some poles in front of your army. Instead of standards, you have your victims held aloft. At the start of the advance, use your flaying knife on a stick to begin peeling the skin from the victim's back around 100 m from the battle. This way, the defending force not only gets to SEE your evil, the will begin hearing it in their heads very shortly before battle is joined. Advance slowly, with archers at the front as long as is possible. Make Use of slingers, siege weapons, anything at all that can hit from more than 100 meters. If it can cause messy and painful deaths from a distance, do it. Aim for gut shots. *Keep ranged weapons in play as long as you can.* Announce to your enemies that you will stop the torture if they stop fighting you. Keep in mind, you actually have to honor this in order to gain trust. You have to mean it, otherwise the defending troops will glean your intent. Tell them that you will accept surrender on a unit by unit basis. take a victim off of the pole for every 100 surrendered. Tell your captured that you only want the unobtainium. Tell them this over and over and over. Next during the battle irregularly and periodically tear another strip off of your victim. to send torture jolts through the enemy closest to you. Every time you do that, rake the enemy with arrows. Archers fire just as soon as they hear the scream. The purpose of all this is to maximize the demoralization without committing your reserves. If you can get them to start surrendering, you can very quickly shift things until you have a huge numerical advantage. Keep on message in a nearly fanatical manner. [Answer] Other answers have focused on how you might turn the psychic powers of your proposed race against them, but your edit suggests that torture is largely ineffective. My suggestion is to **work around their powers**, not try to make them backfire. The range of the psychic powers is about 100 meters. If you can separate your opponents, their fighting prowess will be reduced. So fight with this in mind. Use cavalry to scatter your foes. Unless they have a lot of reach weapons (pikes and similar), they will have to scatter before a concerted cavalry charge. Then ride them down. However, it is quite possible that they will not scatter sufficiently. An even better strategy might be to conceal the bulk of your force. Presumably your opponents will then advance cautiously, in waves, so as to avoid the whole force being ambushed. You can then have hidden cannoneers fire missiles between the groups, so as to make joining together again very risky, and proceed with a cavalry charge from the side. [Answer] Assuming that they are unable to turn their "sympathy field" off, a less subtle torture tactic becomes possible. Stage a few raids to capture as many prisoners as possible, and then build whatever equipment is necessary for your torturers to be able to perform their duties while on the move. The idea being that any of their forces who want to attack yours have to walk through a 100m radius bubble of screaming agony to do it. It will be much more difficult for their psychic soothers to do their jobs while the torture is ongoing than to simply correct the damage afterward. [Answer] **Unpredictable actions** Their psychic power is indeed a great power, and should help them to organize quickly to any form of conventional strategies. But if you launch different undersized and oversized assault, it is possible to make even the greatest leader to doubt. You have dragons, you don't want to use them, simulate them. Make them believe you brought all your army. use other country uniforms. Deceive them the more you can. Prior to assault, burn some villages to the ground and simulate dragon footprints. They will have a lot of informations to deal with, some of them against one another. Information can be a great asset, but If you can't filter it and analyse it, each decision you will take is the wrong one. So this will allow you to confuse the head. If this communication thingy is constant, they will never have fought without it, so even experienced soldiers will be confused, and clumsy. Add some natural fears in the mix, like fires and strange masks, screams, torture. If you have some prisonners, maybe you could deceive them into relaying false information too : Let one ear a conversation about bringing him under the city to perform some new sacrificial ritual with destructive power, make him believe it, and when you assault the city, put bring him close enough and begin the "ritual" he will desesperately cry that you are in this specific part of the city, unleashing a demon and sacrificing him, but nobody will be there, so you will split the army. With a good assault like this, you will have destroyed a significant part of their forces, confused the other parts, and probably had access to huge logistic assets, that you captured or destroyed (or poisoned if it is the water facility of a city). Now you either continue like this to end it quicke before they adapt, or you go back to guerilla style but you will have gain the number advantage. You can also ask for a ransom if you capturesome valuable people or assets. ask for something that will help you win the war. **Other economic means** If they don't want to sell unobtainium, then ask it for ransom against captured people or valuables, use other countries as intermediary, use aggressive monopole strategies to get key ressources of their empire to make them crave it. Use propaganda to direct bandit attacks on them. Any Wussname who wander out of Wussname direct territory should be killed by your spy network, by any means, and same with people commercing with them. **Environment destruction** Poison any river going throught the Wussname country. Burn whatever they are using for ressources which is within your grasp. If some herbs have known influence on people's mood, use them to change the way they are feeling, either to be overly confident, careless, or depressed. you can smoke them in the wind or use them in water. **Shorter Version** Push them out of their confort zone. There is a lot of ways to make them unable to rely on the capacities they have always fought with. emotions and tactic information can be deceived, and can be broken. [Answer] Well, first thing's first, I wouldn't do this while you have another war going on unless absolutely necessary. One of Hitler's biggest blunders was declaring war on Russia (who prior to the war, saw Britian as a bigger threat than Germany and was content to not help the British and had treaties to avoid conflict with Germany which Stalin was so spectacurlarly devoted to, he willfully ignored evidence that Germany was gearing up for an invasion because Germany said they wouldn't do that. He did not treat any military build up as a threat until they crossed the border.). Japan's biggest mistake in WWII was that they underestimated American's conviction to the prosecution of war and mistimed the declaration of war which lead to an unintentional sneak attack at Pearl Harbor. Prior to WWII, Japan had prosecuted a successful war against Russia that relied on hitting Russia quickly before Russia could mount a counter attack. Russia also happened to be in the middle of some social unrest that would lead to the Revolutions and didn't need a war right now, so took the first peace deal they could get rather than commit forces to the front, which if they had would have destroyed the Japanese Army. Japan was relying on this to happen with America and Admiral Yamamoto's famous "Dictate Terms in the White House" warning was ignored (and distorted into a goal when American press got wind of it... American's believed it would be Japan's intention to land on the west coast, march towards the East Coast, and rule the lower 48... in actuality, they wanted islands that could get them rubber and oil for their war in China). Yamamoto, having studied in America, was also well aware of the nation's love of that pesky second amendment and that it meant that the entire populace is armed, which is something I think you're not factoring in. Assuming that there are civillians in Wussname, the psychic nature of the race would mean that in times of war, there are no civillians. Since half your army is away at a current war and your army is four times that of the fighting forces of Wussname, that means your attack force for Wussname is now twice that of Wussname. If they out perform you at a rate of 2.7 to one, that means for every two Wussname forces you kill, you lose five of yours, though considering that on average, devoting three to kill one means one survivor who is at 30% health means the figure is probably going to rise to six. Causalty in warfare isn't the measure of dead troops, but troops removed from fighting by any means (injuries included). My question is then, what is the threat Wussname presents that requires immediate action to respond too. As they are peaceful, you would be the aggressor force, not Wussname so you could choose the time that's most oppertune to attack. If your general is halfway decent, he'll tell you that that starting a new war when one is currently on is not a good idea. Heck, I'm a civillian who learned officer ranks by watching way too much Star Trek and I'm telling you it's not a good idea. Second, if you're going to feel threatened at all by psychic races, perhaps your other enemies are as well. An alliance against the psychic menace would be much more advisable. You're already providing spoils of war to one of the nations most likely to be your enemy in the later future. If you can gin up enough anti-Wussnameism, you can appeal to both the evil empires (they could learn our evilest secrets and tell the world... they must be stopped!) and those noble republics (I mean, come on, they can control how you think... sure, we may take away a lot of basic human rights, but we've never done THAT! We merely enforce correct thought by proper conditioning that you have a chance to resist.). Not only does this net you greater superior numbers and prevents another empire from declaring war on you out of sympathy or oppertunity, but it gets you something way more valuable than your treasure: Operational details of your enemies. By working with them, you can improve your intelligence and strategy of that country you were fighting and the ones you wish to fight in the future. It's quite hard to co-ordinate an attack if your allies are unwilling to tell you their strengths and limitations on the battlefield. (This is one of the reasons that the United States sells weapons to nations of less than savory moral behavior. It's easy to know what the enemy has in their arsenal when they give you the order form for the arsenal.). ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- 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). Closed 8 years ago. [Improve this question](/posts/18962/edit) In a near-future scenario what sort of manufacturing might occur in space? There are several potential advantages to a factory in space. Space provides hard vacuum, micro-gravity, consistent solar power, large amounts of raw materials from asteroid mining, and the ability to vent as much hazardous waste as your heart desires. But what manufacturing processes could actually make use of these features? In our near-future scenario we still rely on chemical rockets to get into orbit and to putter around the solar system. We have captured a few asteroids and comets and nudged them into orbits around the Earth. What products could be made more cheaply or efficiently in space? And could the benefits ever outweigh the cost of transporting the necessary people and/or materials into orbit? [Answer] The biggest advantage of manufacturing stuff in space is that it's *already there*. If you build a spaceship part on Earth, now you have to ship that part out of Earth's gravity well. That's hideously expensive to do - one of the big goals of space exploration is to get transportation down to under 1,000 dollars per pound. So if you make a 50-pound spaceship part, you automatically add at least $50,000 to the cost for transporting it to space. Make that same part in space, and you don't have that cost. Now think about that price difference in say, a pound of screws from Earth vs a pound of screws from space. As for other techniques: 1. You should use robots and [Waldos](http://en.wikipedia.org/wiki/Waldo_%28short_story%29) for most direct manufacturing. Your humans will stay in their safe rotating habitat 99% of the time, remotely controlling bots that do the actual work. This avoids most issues with zero gravity and bulky space suits - the only time they need those is if all the waldos break down and you absolutely need a human on-site. 2. While pollution is less of a concern, you don't want to literally just throw your trash into space. It might literally come back to hit you. It would be better to define a large area on a nearby body - probably the moon - as trash central, and require factories to send their trash on orbits that will impact there. This still keeps pollution disposal very cheap, while not cluttering orbits. Certain pollutants (like radioactives) might need other disposal techniques - maybe send those out to the asteroid belt on very slow, low-energy orbits. 3. I can't speak authoritatively on this, because as far as I'm aware no one's actually tested it. But I suspect that there will be manufacturing techniques that work extremely well in microgravity, especially in materials composition. But we don't have any details on which those would be. [Answer] Just my 2 cents, but a vacuum isn't an advantage it's a disadvantage. It's hard to work in a vacuum - humans need to wear bulky suits and humans are still often needed for set up and repair. Also pistons that rely on fluid would need to be air tight. Space is also full of the occasional cosmic ray and solar storm, so it's not an easy place to work. I'm not sure micro-gravity is much of an advantage either. It's hard to work if the slightest force propels you away from the object you're trying to work on. Low gravity could well be an advantage, but micro-gravity - I think that's a disadvantage. OK, that out of the way, there's no shortage on what they would mine if asteroid mining was cost effective - Wiki has a page on it. <http://en.wikipedia.org/wiki/Asteroid_mining#Financial_feasibility> But the issue is 2 fold. 1) cost and 2) guaranteed return. Wiki makes the point that one particular asteroid > > "16 Psyche is believed to contain $1.7×10^{19}$ kg of nickel–iron, which > could supply the world production requirement for several million > years" > > > When we mine iron on earth, we dig through thousands of tons a day. The trucks alone are as big as a small building and the factories that melt and separate the minerals from the earth - enormous. To do asteroid mining, you have to try to minimize the equipment needed cause launching things in space is very expensive. If it takes 100 years or longer to get equal return on investment - that's not attractive to an average business cause they get killed on interest payments alone. So it's a fun idea, but, for now at least, not practical. I mean, if one company gets an asteroid and a million year supply of Iron - what's to stop a 2nd company from, 20 years later, doing the same thing but with better technology - that leaves the first company holding a big loss. The real trick with space mining is to get the technology to send something in space that can build machines in space - and while that might sound terminatorish, that's really not what I mean. What I mean is, you can't send drilling equipment up to an asteroid the size of Wyoming, what you need to do is send equipment up to Wyoming sized asteroid that can build drilling equipment from the asteroid material, so you can increase production quickly. Right now, we don't have that technology. It's similar to the Mars problem. What we really need is the ability to build things fairly quickly on Mars if we're going to settle there and right now, we don't have the means to do that. Setting up a colony on Mars with today's tech would be very slow, and probobly would lead to the death of the colonists. on Today's tech, it's very hard to see how the benefits would outweigh the costs for asteroid mining especially since the process can be copied by someone else the instant it becomes profitable and the tech is improved. But long term, the benefits of mining something as simple as Iron in space is obvious - because ultimately, it's more energy efficient and cost effective to build things in space than to keep sending stuff from earth into space. . . .but we're not there yet technology wise. How long it will take for that to happen, that's hard to say, but at some point, with improving technology, I think it's sure to happen, and when it does, mining for basic stuff (Iron, water, nitrogen, carbon, oxygen) and for more exotic stuff (Platinum, Iridium, etc) and possibly helium, which we don't think of as valuable, but it could become valuable if Fusion ever gets figured out. I'm sure it will make sense eventually, but perhaps, mostly not to send back to earth, but for building stuff in space. at least, that's my thinking on the subject. [Answer] So: supply and demand has made something economical to make in space. But there's a catch: space is very expensive to go to. It has a lot of special properties but it is fundamentally an expensive place to visit, so whatever you make in space has to be incredibly valuable(and not just decoratively. It has to be used for something and there can't be good alternatives). (It occurs to me that human nature is kind of awful and therefore there will be people who sell space tomatoes for exorbitant prices specifically because they're exorbitantly expensive and rich people will buy them to impress one another, but that's boring.) There's one thing space (well, orbit) has that Earth doesn't have. Well, the other way around. It's gravity. Space has microgravity environments for minutes or hours at a time, and there's no way to do that for more than a few seconds on the ground. Hard vacuums, radiation, energy, isolation are all doable(if expensive) on the ground. And what can you do without gravity? Grow crystals, incredibly perfect ones. Isolating your crystal pods from vibrations and convective forces as the crystal forms lets crystals form with much fewer deviations or defects. The crystal growing chamber has a seed crystal and some solution, and all it needs is to cool down very slowly. That's really easy to build with zero moving parts and no maintenance required, so living spaces for human beings(expensive and breakable) is minimized and productive crystal aging vats are maximized. Superconductors are strange metal crystals that benefit from extreme regularity, perhaps space is the only place they can grow stable enough to work at room temperature. Maybe they're just growing giant germanium-doped silicon crystals for really sensitive radio receivers. Or giant perfectly regular crystals to build gravity interferometers for detecting cloaked spaceships by their gravity signature. Giant protein crystals for X-ray diffraction. Or giant rock candy, or all of the above. [Answer] **Starship fabrication** I would only build things in space that I could build using resources already available in space and that aren't required or designed to ever enter a gravity well or atmosphere. Once a certain tech level is reached, large space-going vessels that aren't intended to ever make planetfall would likely fit that requirement. Due to the hostile environment in outer space—hard vacuum, significant radiation, and lack of gravity or atmosphere—life support costs alone will naturally make any construction there more expensive. However, the energy cost to lift something out of a gravity well is also significant and will remain so. [Space elevators](http://en.wikipedia.org/wiki/Space_elevator#Climbers) will be volume-constrained, even though they will [greatly reduce the cost per mass unit of getting stuff into orbit](http://en.wikipedia.org/wiki/Space_elevator_economics). Therefore, the only case in which the savings from space-based construction will outweigh the costs is for huge, heavily automated endeavors that require massive amounts of raw materials, and then only when the vast majority of those materials can already be harvested without entering a gravity well. Aside from that, the only things you'd want to make in space are things that require microgravity to make. Currently, that list consists solely of large, symmetric, and perfect crystals, although technological development could obviously change that. [Answer] Solar energy collectors is an area of active research. See <http://en.wikipedia.org/wiki/Space-based_solar_power> Although if we are putting asteroids into LEO this might become less attractive, one of the major issues with space based power stations is degredation due to space junk. [Answer] I have a somewhat low-tech sounding, but totally practical, suggestion: ball bearings. Currently, in order to make high-quality ball bearings, the metal is stamped into a form, made slightly too large (to account for the mass that will be lost in the next step), ground and polished for hours on end to make it round and smooth, and it *still* doesn't come out as perfect as if one simply extruded a precisely-measured quantity of molten metal into a micro-gravity environment and let it find its own shape. The process, because it's so simple, could be handled almost completely autonomously. Now, as others have noted, the cost of launching materials into orbit in order to manufacture stuff is usually too prohibitive to bother with. But if these asteroids you mention can be mined for iron and other necessary elements (which I guess is the point) then the materials are already on hand, and the process becomes reasonably cheap. You then only need to find a way of getting the finished product down to Earth where it can be used (parachutes, heat shields, the usual). If I could make one other suggestion: if you allow nuclear (as opposed to chemical) rockets in this scenario, everything starts to make a lot more sense. Nuclear rockets aren't some far-out imaginary technology we'll never live to see, either, but are theoretically very possible, and an active area of research within the space-tech field. They're probably closer on the horizon than asteroid mining, frankly. With a basic design, you could assume a 2-3x improvement in rocket thrust-to-weight ratios, which makes things like mining (and relocating) asteroids that much more practical. [Answer] I would like to think about **advanced weapon manufacturing.** A big lab 'ship' in space that houses inventors and officers that dedicate their life there. They manufacture and develop secret weapons such as missiles and nuclear bombs that could be launched from space. They could manufacture top secret weapons in order to hide them from secret intelligence and spies. They could manufacture advanced aircraft that could launch from space and attack any country in the world. This would be useful if you were attacking an area where you had no military bases. Maybe such a station would be useful for defending against aliens (You never know). ]
[Question] [ *Edits are in italics*. To narrow it down more, can you have 'magical' force that doesn't have laws the way physics has laws? For example, in Tamora Pierce's books, magic is tied to the users physical and mental strength. The magic is a bit like a muscle, you can build it up, but everyone's maximum strength levels are different. It you use too much at once you die. Can a world exist without universal restrictions, or would the magic force simply make it uninhabitable for continuous life? *Can magic, if it were a random force creating and uncreating things, a bit like the Infinite Improbability Drive (that spaceship from Hitch Hiker's Guide to the Galaxy) be forced to follow rules? It doesn't necessarily do exactly what you want it to, or even close to what you want it to.* I understand that this is a very vague question, I am have trouble describing the phenomena. This is for a book series, not an RPG (at least, for now) the story will focus on the main characters trying to make rules the magic will follow. [Answer] Yes, you can! The one caveat is that whenever you have the characters use magic to solve a problem, as opposed to having characters having to solve problems caused *by* magic, you risk writing a deus ex machina. Like [Cort Ammon's answer](https://worldbuilding.stackexchange.com/a/13239/214), I'm going to recommend reading [Sanderson's First Law of Magic](http://brandonsanderson.com/sandersons-first-law/). However, I disagree strongly with Cort Ammon's claim, "Sanderson's First Law of Magic suggests it is remarkably difficult to use such a rule-less magic in a book." If you read the article on Sanderson's First Law, Brandon Sanderson writes most emphatically that magic systems without rules can be effective! He does give some advice on how to use them in your storytelling, though. In particular, he says that such magic systems should be used primarily in one way: **to make it very clear that the main characters have little control over their worlds.** To quote some of the article (emphasis mine): > > I [developed] my first law as a way to include magic systems **that don’t follow very strict rules**, but which also don’t undermine their plots. [...] > > > This leaves room for those who want to preserve the sense of wonder in their books. [...] Books that focus on this use of magic tend to want to indicate that **men are a small, small part of the eternal and mystical workings of the universe**. This gives the reader a sense of tension as they’re never certain what dangers—or wonders—the characters will encounter. > > > Sanderson continues in his article to say that the major weakness of a magic system with few rules is that, in most cases, resolving conflicts with this magic cheapens the story. As I wrote above, there is great risk that it will come off as a deus ex machina. This is because, since magic cannot be understood, any time it helps out the main characters greatly, it can break suspension of belief. Sandrerson writes: > > The really good writers of [magic systems without rules] **very, very rarely use their magic to solve problems in their books. Magic creates problems**, then people solve those problems on their own without much magic. [...] > > > So, if you want to write soft magic systems, I suggest you hold yourself to NOT letting your magic solve problems for your characters. If the characters try to use the magic, it shouldn’t do what they expect it to—as the reader doesn’t know what to expect either. Use the magic [...] to screw up things for the characters. > > > Looking at your original question, I noticed that you wrote, "[T]he story will focus on the main characters trying to make rules the magic will follow." This is very much in the spirit of Sanderson's first law! I believe that you can create a successful world with strong narrative potential based on your goals. [Answer] Yes, however, [Sanderson's First Law of Magic](http://brandonsanderson.com/sandersons-first-law/) suggests it is remarkably difficult to use such a rule-less magic in a book > > Sanderson’s First Law of Magics: An author’s ability to solve conflict > with magic is DIRECTLY PROPORTIONAL to how well the reader understands > said magic. > > > It is simply easier for readers to understand the magic if there are rules governing how it operates. There are absolutely ways to help a reader "understand" the magic without rules, but it will be up to you to figure out how to do it in your particular story with your particular readers. Magic systems that seem to revolve around things like "love" and "harmony" have a tendency to be very understandable without resorting to rules. If your audience is teens, magic systems which reflect the chaos and complexity of puberty also tend to come across as highly understandable. Good luck! [Answer] Have magic behave like the weather. There are definitely rules, but it is part of a whole so vast, with so many factors to take into account, that it is impossible to properly predict the outcome of anything remotely complex. Let's say in your world someone wants to light a candle. It's an action that is fairly simple, it should work always as expected 99,9999999% of the time. However start trying to summon up fire beings or create a firestorm and you may end up firing up the nearby volcano instead or accidentally putting out every single fire in the province or even burning your neighbors' cooking. [Answer] I can think of a few works which might be of use. They all fall into the category of "making sense out of apparently nonsense rules". ["Harry Potter And The Methods Of Rationality"](http://hpmor.com/) is fanfic exploring the opposite: an analytically trained Harry Potter tries to make sense of the magic in the Wizarding World using the scientific method. It's meant to teach you how to think, and it's a great read! It might give you ideas to read it and see the sorts of objections Harry has when he tries to make sense of the apparently nonsense rules of the Wizarding World. For example, when he [tries to figure out how his magic bag works](http://hpmor.com/chapter/6). > > "Aaaaaaarrrgh this doesn't make any sense! " > > > The witch beside him lifted a lofty eyebrow. "Problems, Mr. Potter?" > > > "I just falsified every single hypothesis I had! How can it know that 'bag of 115 Galleons' is okay but not 'bag of 90 plus 25 Galleons'? It can count but it can't add? It can understand nouns, but not some noun phrases that mean the same thing? The person who made this probably didn't speak Japanese and I don't speak any Hebrew, so it's not using their knowledge, and it's not using my knowledge -" Harry waved a hand helplessly. "The rules seem sorta consistent but they don't mean anything! I'm not even going to ask how a pouch ends up with voice recognition and natural language understanding when the best Artificial Intelligence programmers can't get the fastest supercomputers to do it after thirty-five years of hard work," Harry gasped for breath, "but what is going on?" > > > "Magic," said Professor McGonagall. > > > "That's just a word! Even after you tell me that, I can't make any new predictions! It's exactly like saying 'phlogiston' or 'elan vital' or 'emergence' or 'complexity'!" > > > The black-robed witch laughed aloud. "But it is magic, Mr. Potter." > > > --- ["The Order Of The Stick"](http://www.giantitp.com/comics/ootscast.html) is a web comic about a adventurers in a world which follows the rules of Dungeons And Dragons *and the characters know it*. But unlike other works which break the fourth wall, this is just how their world works. They treat the rules of D&D like we treat physics. In particular, Bards are people with the skill to explain why things happen and predict what will happen next by studying the plot, theme and tone of the story. Things just happen to you because you're the hero. They frequently [rely on action cliches](http://www.giantitp.com/comics/oots0389.html). > > Elan: Really?? Wow, what were the chances? > > > Julio: Pretty good, considering we wouldn't be having this scene if it didn't forward the plot in some way. > > > Elan: Oh, right. > > > --- [The Uncertainty Principle](https://en.wikipedia.org/wiki/Uncertainty_principle) isn't a work of fiction, it's how our universe fundamentally works. Put informally, at the smallest scales everything is fundamentally uncertain, everything is a roll of the dice. At normal scales it all evens out and you can pretend the Universe is clockwork, that's [Classical or Newtonian Mechanics](https://en.wikipedia.org/wiki/Classical_mechanics), but it's all based on the average probabilities of bazillions of tiny interactions. This leads to weird edge cases like [quantum foam](https://en.wikipedia.org/wiki/Quantum_foam) where "empty" space is really pairs of particles and anti-particles popping into existence and immediately annihilating each other, and [quantum tunnelling](https://en.wikipedia.org/wiki/Quantum_tunnelling) where because the position of a particle is uncertain it can appear to pass straight through an impassible barrier. So, in a sense, what you're describing is our own reality. [Answer] > > Can a world exist without any sort of universal restrictions, > > > Sure, we live in a world where micro scale physics and macro scale physics require two different math models to calculate, and the universe still seems to be around last I checked. To explain further, there is no inherent Metaphysical force that will cause the world to destroy itself if two parts of the world function differently. Of course, this being your world and your setting, you could simply say that there IS some force that destroyed the world because some parts of the world is functioning differently, however, it may be difficult to write a story set in a setting with no world. > > or would the magic force simply make it uninhabitable for continuous life? > > > Funnily enough, the answer to both parts of your question can be yes. You could say that the force that dislikes differing rules may also completely neuter any and all life on the world, which only makes it more difficult to write a story with no characters or world [Answer] I have two answer - and they may contradict each other. First answer: the universe IS magical, and it does follow rules that we are still trying to fully elucidate. Second answer: assuming you mean "Harry Potter" type of magic, then the answer is clearly 'yes'. Such magic implies limitless 'jump the shark' outcomes, which implies that there are no rules. Magic implies no laws. You write a story with magic rules and I can write a sequel where a wizard has magic to break those rules. Such magic would contradict the known universe - which does have rules. Like I said, my answers contradict but are both true. Interesting. [Answer] It is possible to write magic without rules, probably the best example of the thought behind this is when asked about the speed of his ships someone (probably in regards to firefly) replied that they travel at the 'speed of plot', this allows you to use any magic that helps the plot (not necessarily the characters). Another approach is to have rules and tell no one what they are. This is a great method to allow the characters to think they know what is going on, but be wrong having incomplete or inaccurate knowledge of the rules. [Answer] This is how I'd do it: Write a big list of possible outcomes (and number them), then every time the 'random' spell is evoked, use a [true random number generator](https://www.random.org/) to pick the outcome for the story. You could take this a step further and get your random results via randomly generating a number and using it to select a random word from a random website, or some thing like that perhaps. [Answer] > > the story will focus on the main characters trying to make rules the > magic will follow. > > > That is not actually a magic without rules. There are two options: ``` 1. Magic has rules, but they have not been discovered. 2. Magic has rules, but the way they interact with magic use is undefined. ``` The first case should be pretty clear. This is how science works. Thunder was magical, incomprehensible, thing beyond human power and understanding with a powerful god behind it. Until science explained it. Not sure you could write on riveting story of magician experimenting to discover the rules of magic. Then again lots of the scientists behind major discoveries really were quite exceptional people with interesting personalities and stories. And you could use those real world stories as a basis for characters, so it might work. Still, I think you mean the second case. I actually have read a series that had this as the main plot. The world had supernatural spirits or whatever that made reality malleable and interacted with human minds. When first settlers arrived the events "imprinted" magic with a certain pattern of interaction, which turned out to be undesirable. So later the main characters used a ritual to re-imprint magic with a new pattern. If we replace the "undesirable pattern" with "no coherent pattern established" this sounds a lot like what you wanted. This is actually the model used in quite a lot of stories with super powers. Since the various universes were originally assembled with separately created fragments without any real overall planning and coherence, different people would have different powers with entirely separate rationales. By now this has become traditional so even settings that are otherwise coherent do not try to make powers of different characters to make sense together. So I guess in a world with magic like that, magicians would be very similar to mutants in Marvels X-men. Magic would awaken in puberty, and each magician would have his own unique powers with its own unique rules. Essentially the will and mind of the magician would force the rules or pattern of interaction on the magic. It would work the way it works because the magician believes it does. And the magician would believe it works the way it does because that is the way it works. A self-reinforcing loop. Reasonably since the expectations of magicians would impact the original power and pattern different cultures would have widely different traditions of magic with entirely separate common powers and patterns. Since magic comes from interaction with external field magicians would presumably be stronger in areas where people believe in their tradition. So if you were able to construct a model of interaction with magic that has the properties you wish and then imprint that model on the magic itself, you could become quite powerful and make your enemies nearly powerless. Even better you could connect power with actions and patterns you approve of and disconnect it from patterns you disapprove of. Human sacrifice is an easy example. You could make even your enemies act the way your prefer... ]
[Question] [ I have an idea for a Young Adult fantasy, a small number of teens are visited by characters from 'fantasy' world, at which point they learn that most of our fantasy worlds exist and that magic works in our present world. They are attacked by a few people selected by an enemy as their opposite number, also empowered by magic. My big problem is guns getting in way of a more magical & sword vibe I want to go with. I'm okay with guns being present to some degree, but I don't want them to be the main characters primary weapons. I also don't like how instantly fatal they are. I want my heroes to be strong enough to have a significant effect in the world, but it doesn't matter how much magic they possess if a single sniper rifle can stop them effortlessly. Thus I would like to come up with some way of justifying the limited use of guns or cut their ability to completely neutralizer the protagonists. **The Premise** It's a pretty straightforward plot as described above, other than the fact that it's going to have some actual death involved. In some ways, it's a partially deconstruct the standard YA magic hero story. The sudden presence of magic can't stay a secret and ends up being national news and even starting battles. The heroes can't resolve things without the use of force, there will be a need for some to be willing to fight and kill, and at least one of the heroes and some of their fantasy guides will fall in the fight. I'm not going entirely gritty deconstruction, some of the general YA optimism will exist and the teens won't be completely destroyed emotionally by the need to fight, but I am trying towards a more realistic [Reality Ensues](http://tvtropes.org/pmwiki/pmwiki.php/Main/RealityEnsues) story while still keeping some of the YA tropes and general fantasy. Lots of the fantasy guides are from Eastern Style RPGs, so think of any Final Fantasy to get a general feel for what the combat should be like. Lots of magic and swords and protagonist with a bit of [Charles Atles Superpower](http://tvtropes.org/pmwiki/pmwiki.php/Main/CharlesAtlasSuperpower) when it comes to their skill with melee weapons. The heroes all gain some level of enhanced physical fighting ability (the ways very, but generally fit under 'knowledge of fighting magically bestowed upon them' or 'prior training in actual martial arts or fencing, but with their magic abilities used to enhanced their physical skills'), with two characters playing the 'pure mage' role of no physical fighting skills. One of the 'enemy' teens has a gift for bringing in people from other fantasy worlds. He declares himself the president of the US and starts bringing in the military from a fantasy world to enforce it. This military goes up against both the disorganized US government's military and our heroes as sort of 'mooks'. Generally, they're treated as less dangerous then our present military, but they have numbers. My problem is that I want to try to justify a group of a few dozen, at most, heroes, all either larger than life fantasy heroes or teens with powerful magic, going up against a larger force of 'mook' soldiers. I want a real fight scene, so saying the teens just nuked everything with fire before the enemy knew what was happening is not really a possibility. the teens can do lots of 'weak' attacks, maybe toss a lightning bolt that zaps 3-5 soldiers at once, but they can't just nuke everything at once. I want a real challenge in such fights. The enemy force consists of soldiers from a world that is a little past fantasy, but where swords and magic are used as often as guns. I'm going to claim that military tradition causes them to frown on guns and that a combination of limited gun crafting ability and armors that are effective against guns but not close range weapons all combined to lead to an emphasis on close range and magical fighting with guns used only to supplement the main force. However, *OUR* guns are still powerful, and it wouldn't take long for the enemy forces to realize they can go out and buy better guns at the local shop, or hire soldiers & mercenaries. How can I either limit adoption of our weapons or create a believable way to limit the power of adopted weapons? **The Magic** The premise of this world is [human belief in something can make it happen](http://tvtropes.org/pmwiki/pmwiki.php/Main/ClapYourHandsIfYouBelieve). The fantasy characters that come to our world to meet with the heroes come from real worlds that mimic popular literature because of the combined belief of people reading these literary works, and allowing themselves to imagine them as being real, was sufficient to make these worlds actually exist, giving life to the characters within them. The reason that our present world doesn't see any magic is that we all collectively believe magic shouldn't exist, and our collective belief in magic not existing keeps it from happening. However, if one person believes hard enough in something magical happening their one strong belief in something occurring can be enough to overcome the passive disbelief of others long enough to make the magic real. The protagonists do not know this, they simply know that people showed up that shouldn't be able to exist and tried to drag them to a meeting without explaining why; only later did they discover they could work magic (having been inspired to believe in it by the sudden presence of so many other fantastical things). They were each selected by their creativity and ability to believe, effectively they were chosen as the teens most capable of using magic, but the fact that they don't know *why* they can do it limits their belief in their abilities and thus the power of their magic. Each hero's magic feels very different because they each believe that magic should work differently, and each subconsciously places limits on what they can do because they believe those limits should exist. The enemy has been told how magic actually works and as such they better believe in their magic without limits and are therefore individually stronger than the heroes. [Answer] There are a lot of things that could be done here...but here's an option for you that I think plays well thematically with how you describe magic working. In short, belief-based probability bending... aka, your main characters literally have belief-induced plot armor. People believe that heroes don't just go down in a hail of gunfire. We see this in film and literature all the time. Batman flips his way through gunfire all the time and is generally unscathed unless he needs to be injured for a plot related reason...and even then, it's seldom a debilitating injury that causes serious damage. And James Freaking Bond...heaven only knows how much lead has fruitlessly been fired at him. This is something well engrained into culture and into the human mindset. In reality, a few targets against many with guns ends in a hail of lead. But a hero has plot armor. Bullets simply fail to hit him, explosions knock him away instead of pulping his innards, and so on. It is that belief that protects the heroes. Sure, in close combat against a few enemies, they can be defeated...in a duel they can be killed...but against a hail of lead from faceless mooks? Meh. Against a cheapshot from a sniper? He'll miss and shoot the glass out of their hand instead. It's not that they are messing with the aim of their enemies...it's that their 'plot armor' basically bends bullets around them to protect them. Maybe this is a little too meta for you...but hey, I thought it was fun. [Answer] The latent magical fields that surround spellcasters have a weird, sort of dampening effect on ordinary matter. Almost as if the caster is incased in a sort of jello. While the effect is fairly weak, anyone non-magical moving near a mage can feel the drag. You move more sluggishly. Your arms feel heavier. Your punches swing slower. The more powerful the magician, the stronger the effect. The lighter the object in question, the stronger the effect. So yeah, a competent mage getting shot at? You can visibly see the bullets slowing down as they approach and bounce into the magical field around him. He can dodge them by stepping aside. If he gets hit, he'll have maybe a bruise. An arrow, being much heavier, can still have enough stopping power to kill, although most mages are quite capable of sidestepping those as well. Or take the time to cast a spell to block them. A sword to the face would still hurt, although the stronger the wizard, the harder you have to swing to be fast enough to wound him. Other magical fields seem to ignore the effect completely; a magical sword cuts through even the most powerful mage's field with impunity. A magical arrow flies in at ordinary speed. A magical bullet... well... it would kill a wizard easy. Only problem is; magically enhanced materials are much harder to work with during smithing, are ridiculously expensive to obtain and almost every part of the proces has to be done by hand. There´s simply nobody in the world who has the kind of resources to build a factory that produces magically enhances rifles. Crafting a modern gun by hand is hard enough, but using a magical material to do it? You simply cannot work it well enough to make such a device. Maybe a primitive gun, if you try really hard, but even those are probably no match for tossing a lightning bolt, so none are known to exist. * Yes, this is just making plot armor an inherent property of magic. * Allows sudden, enhanced fighting ability for mages * Bullets are useless against mages * Arrows are not * A magical artefact gun could still be a potential threat, but it'd be a major plot point [Answer] A little precognition could go a long way. Not even that much or that specific... 5 seconds of a bad feeling would be more than enough. Sniper pulls the trigger, the hero senses it and moves 3 inches to the left until the bad feeling goes away, and the bullet goes whisking by. This wouldn't be plot breaking because enough bullets, or being distracted and ignoring the feeling would prevent the hero from dodging. Also, not all the heros need it, just the ones you don't want to get shot. [Answer] Guns have no defenses against magic and lots of fiddly little moving parts. This means that you could have it trivial for the heroes to disable the enemy guns with a simple spell or ability. Snipers are harder but defenses could still be put in place. For example being able to detect hostile intent/an attack even without needing to see the attacker. [Answer] This is a two-part answer. As you said, magic can be influenced by the subconscious. This means that the reality bending magic of your world would in fact make it totally plausible that if a character believes he or she is the hero of the story, bullets can't touch him or her. The subconscious then acts to make it so. If you're asking for a non hero-armor answer, guns are very... delicate. Take for example the protagonist of The Irregular at Magic High School, he can disassemble most guns with a sweep of his hand or a simple spell. Guns are at an almost irreducible complexity level. Undo a few screws and viola the gun is no longer operational. This would also keep archery to a minimum as bow-string are easy targets for cutting spells. Also, if the magic user is at all good with fire, seeing a gun's magazine would allow them to ignite all the bullets in it at once causing much damage to the gun and whoever had the gun. [Answer] A difficult question. I can only think to solve it in 3 ways. * Why you want a pistol if your magical arrow can hit the target behind a wall? This have the problem than then how you protect them from magic. * The use of advanced weapons is dishonest and enemy society is very honourable and prohibited it clearly. (about this). This is very strange in a "evil" society. * They are protected by magic of another powerfull (and provably ancient) source like a wizard or a prophecy that must happen. [Answer] Depending on how you WANT your magic system to work, this could go MANY different ways.. But I think you underestimate just how much of an impact a so-called "weak" attack like a lightning bolt that zaps 3-5 people at once really would have on a real-world situation. A lightning bolt is an INCREDIBLE amount of energy packed into a compact space. Therefore, your protagonists are already not "weak" by any stretch if they can manifest such amounts of energy with little to no effort. Guns work and are effective because they are a quick and easy way to mimic the effect of putting a lot of energy into a relatively small space. Eastern style RPGs VASTLY underestimate the effect guns would have on a battle. Even steel plate armor was insufficient against medieval guns, therefore armor is out of the question. Especially if you are talking about defense against MODERN guns. In a story that tries to mimic real-world battles, guns will ALWAYS win against swords. And, honestly, no military leader worth anything would frown on guns, unless those guns were INCREDIBLY expensive or otherwise not worth the cost... However, if your protagonists can cast an enchantment that, perhaps, creates a magnetic field or energy shield around themselves, such that the bullets are deflected or stopped, that would work even against things like grenades or other small arm explosives. [Answer] How about inverting your basic premise: "human belief in something can make it happen"? So, within the vicinity of your magic-wielding teens, guns don't work because the bullets travel so fast that they are invisible. And if it can't be seen, it can't be so. Swords work, axes work, arrows work (sort of) armor is impenetrable because it looks impenetrable - but bullets and explosions simply don't register. This will have other implications, and require careful handling. Tanks, for instance, can still crush people, even if they can't shoot them. [Answer] Well, most gunshot wounds are not in fact immediately fatal or incapacitating. That's why [stopping power](http://en.wikipedia.org/wiki/Stopping_power) is a concern for weapon users. Usually if you need to immediately kill someone, you need to shoot for the brain, and landing such a hit on a moving target is so difficult that most military and law enforcement professionals are trained not to even attempt those shots. If your magic is based on willpower and *clap your hands if you believe* principle, then you could have the heroes simply shrug single gunshot wounds off as "just a flesh wound", action hero style, and magically heal them after the fight. This gives your heroes/magic users a superhuman capability to withstand gunfire. Guns are, however, still somewhat effective - if a gunslinger can land a headshot with his handgun (a *really* exceptional feat), a sniper can get a headshot in (pretty tough to do - real snipers don't generally attempt this) or someone can manage to hit the hero close in with a shotgun, they can kill them. They have to fight for it though; either they need to get close enough for the heroes to fight back with magic, or need to be really elite. This might or might not fit your intentions. [Answer] First off, **limiting of spells**. In order to receive assistance or not arouse the wrath of some governing authority, the kids must sign the "Covenant of One". After they do, no single spell can help or hurt more than one person at a time. This creates single combat situations, and a the all-too-human search for a loophole. Next, **guns**. In *Dune* there was a personal shield that slowed things down, like bullets. This prevented lasers (which would cause the whole block to explode, killing shooter and target). It meant that they practiced knife combat a lot. Maybe there is a shield spell that slows all rapid objects down if they approach the body, permitting an adept to dodge. It will still allow air molecules to enter, allowing breathing, but it would make the air frosty after awhile, because all the warm molecules would be kept out but the cold ones admitted. More about **guns**. Another approach is to fire the O'Reilly curse: the "No-spin zone". It prevents bullets from rifling as they exit the gun, increasing friction and making the bullets veer off after they leave the barrel. Or an anti-fever spell that prevents anything from getting hotter than 98.6, which prevents ignition of the bullet's propellant. (To cast this spell, you need more cowbell.) [Answer] Kinetic energy shields such as those featured in the 'Dune' series by Frank Herbert. The shield could be a protective amulet or a spell. It would also give you a reason for using swords and stabbing weapons in the modern era. [Answer] They get magic rings, bracelets or necklaces to wear, these are specifically crafted to protect against anything traveling more than X feet per second, and if it does, it is slowed to that speed. The slowest 22 bullets travel at about 500 feet per second (340 mph). The fastest thrown baseball was 105 mph (154 feet per second), which is also (logically) about the limit of how fast an arm can strike. I am not sure what damage a bullet (with much less mass than a baseball) would do at 150 fps, but I should think it is not much unless it is sharp and lucky (in the eye, in the carotid artery, etc). for the most part it would scratch muscle and bounce off, and light leather armor would stop it. The protagonists do not have to know it works because they believe it works, they just believe it works because they SEE it work, either in an explicit demonstration by a helper, or in battle, people with the protective device are effectively protected in a hail of bullets, others without it get slaughtered as they would expect. Of course, knives, swords, spears, mace, or a board with nails in it all continue to work normally, being human powered they don't exceed the speed limit. Arrows may be slowed a bit, but with greater mass than a bullet could still be sharp and lethal. The excuse for not having an even **greater** restriction is that the wearer is subject to the **same limitation** within the field generated by the object, so to fight effectively the field cannot slow **them** down, and thus cannot slow projectiles down any further than how fast a human can move. ]
[Question] [ I understand that generally, beings get as big as the thing(land, sea etc)they live on or in however another celestial object can interfere with size, like the moon and ppl got smaller. But can a molecule somewhere completely foreign to this realm be for instance as large as a dog or horse, human or house? Large enough to see with the naked eye? [Answer] **Polymers** can be as large as you like. Th best examples are probably car tyres or other rubber objects which are (mostly, probably) one large cross-bonded molecule. A textbook example (literally) is a bowling ball. Of course, those tend to have other layers underneath, but the principle is there - and comments have found some impressive ones. A polymer is a chain of monomers (hence the name), where each unit is pretty much the same as the next. Occasionally, the head of a chain binds to something that isn't a monomer, and it ends. (Or perhaps manages a complete loop.) However, carbon-based chemistry has up to four different covalent bonds from a single atom, and so you can "decorate" your polymer strand with other things which are still chemically part of the same molecule. If one of those things happens to be a link to another polymer strand, you now have two chains which are, in theory, part of the same molecule. If you mix in a lot of "cross-link me" and "fork the chain" impurities so that any given chain links to an average of two dozen others, it's easy to see how virtually all the chains will be connected to each other *somehow*. On a typically-smaller note, still working with covalent-bonded carbon: **Graphite** (as found in pencils) is a flat-sheet and a single molecule. It may form in non-earthlike atmospheres as a kind of snow. **Diamond** is three-dimensional, and works on the same principle. If you're willing to settle for a crystallised stellar remnant, then a 4000km molecule is about 50ly away, apparently known as "Lucy". (Link in comments, credit where it's due.) Some designs for a space elevator based on carbon-filament cables stretching into orbit would count. These are made as covalent-bonded structures because fibres tied to each other just can't handle their own weight when they're supporting over 100km of cable. [Answer] While no longer in the realm of chemistry a neutron star would also sort-of count. And here you are talking about a significant fraction of a Sun-size star's mass. ]
[Question] [ Castles, particularly Concentric Castles, are great to have against the technology of the time; swordsmen, crossbowmen. They're less great against ornery wizards and capricious dragons. The lords of the land got tired of the occasional wizard tossing a fireball in their courtyard and flying off at a height that mere bolts and arrows couldn't reach. Strangely, they were also sick of the odd dragon swooping off with their livestock, gold, or family members. They were most perturbed by the dragons buzzing their walls with breath, taking out many of their men. How did they counter this problem? Assumptions are as follows: * Magic is reasonably common, but the kind of magic that lets an individual swoop in and take out a few dozen troops is rare. * Dragons exist, have various nasty kinds of breath, and are smart enough to demand ransom. They're also only slightly more common than the Wizards. * Technology is Late Middle Ages. * Kings are likely to have someone on payroll who can use magic, or at least knows a lot about it. * Dragons and Wizards have a hard enough time knocking over walls. The lord does not wish their castle's look ruined, not to mention that sometimes they'll be expected to deal with all three threats (besieging armies, dragons, and flying wizards) at the same time. [Answer] The short version is: Add roofs to the keep, towers, and along the walls. But first let's understand the difference between castles and underground bunkers. ## Castle vs Bunker Castles use height as their defence, while bunkers use depth. Height allows you to see further, to shoot further, and to get more angles of attack on incoming sieges. A tall wall also prevents siegers from just walking into your castle. In particular, it deals with the concern of cavalry, as it's difficult to get cavalry into a castle unless you control the gate house. While a few bunkers are tall like a castle's keep, many sacrifice these advantages of height for greater defense against artillery. By burying yourself in dirt, you can use hundreds of tons of earth as a shield. They deny entry not with large stone walls, but with barbed wire which you can see and shoot through, and with powerful artillery and machine guns. They are heavily roofed, as they expect to be hit by indirect fire and air attack. In the world wars, there were many fantastic bunker castles which were very expensive. These were pretty great, but the Germans in both wars demonstrated the ability to construct and transport massive artillery pieces which could tear these apart. So the cheaper and more effective bunker design was adopted. ## **How to defend against medieval flying creatures?** Short version is: Ranged weapons and roofs. Man towers with light artillery weapons, probably ballistas, and light cannon if you have those. And plenty of ranged troops who can shoot any enemy that gets close. Keep look outs who watch the sky from several angles, to try and prevent the enemy using clouds and the sun as cover. And make sure there are roofs that protect your troops and deny intelligence to the enemy. Magic, I'm less certain of. You could always try to rig a giant fly-zapper, if that works on hawkmen. Maybe cover your castle in magical wards that make curses and spells less effective? You'll want roofs that your men can climb onto via ladders, so they can fight any flying enemies who land on the roofs. You also want to have it so that there are always some archers who have a clear shot at a given roof, so your towers and walls can cover each other against this. And as always, firefighting will be important. And for high-flying enemies... you'll want heavy mortar artillery if gunpowder is available, that'll preferably send exploding shrapnel ammo high into the sky (medieval flak). If you don't have that, you'll have to build something like a giant ballista that shoots bladed nets or something like that. Otherwise, all you can do is use magic or hire a flying creature to deal with these high fliers, your only other option being to try and ignore them and perform damage-control. If flying creatures are a big problem in your area, more than cavalry and infantry, then you should just make a bunker. [Answer] ## Stretch thin wire and rope from ramparts to battlements to towers Even if it isn't strong enough to damage the flying [dragon, hawk-man, roc], the risk of them getting tangled/falling to your troops below should help keep the skies in the immediate vicinity of your castle clear. Yes, a creature like a dragon could burn through it, that's why you make it thin enough that they can't see it easily. This means the dragon is forced to expend energy in fiery/acid/ice breath when anywhere near the castle's sky. ## Barrage balloons [Barrage balloons](https://en.wikipedia.org/wiki/Barrage_balloon) were used in the world wars to help prevent against dive-bombing aircraft. I think they should work against dive-bombing dragons. One disadvantage against dragons compared to aircraft is that dragons have fiery breath, and aircraft bullets do not tend to set things alight. So you may need to enchant your barrage balloons against fire. Barrage balloons require higher technology level compared to just stringing ropes around, but will defend your castle higher up. This prevents dragons from carrying stones aloft and dropping them on your troops. [Answer] **Don't neglect your defenses against conventional foes.** Sure, dragons are a problem, but so are angry peasant mobs and the armies of rival lords. In WWII, Germany came up with [above-ground air defense bunkers](https://en.wikipedia.org/wiki/Flak_tower). These "Flaktürme" were a combination of an air raid shelter and a firing position for air defense artillery. * Think of something like [Bunratty Castle](https://en.wikipedia.org/wiki/Bunratty_Castle) with with a massive central keep and relatively small outbuildings. * Put [Ballista](https://en.wikipedia.org/wiki/Ballista) and [Scorpions](https://en.wikipedia.org/wiki/Scorpio_(weapon)) on the towers. [Answer] A rookery. A large group of ravens with cock-fighting barbs on their legs. They can out-maneuver the larger dragons, attacking its rider and weak points, like the eyes. If you have the right kind of wizard, you could even put bombs on some of the ravens, and have them akbar into the oncoming dragon. They might not even need any training - they could instinctively attack the dragon as a flock, just like dolphins will attack sharks. [Answer] **Don't let them get close to your castle**. Instead of waiting for the enemy to approach and destroy your castle, intercept their armies midway. Since magic is reasonably common, it shouldn't be to difficult to create a magic reconnaissance system to detect invading armies before they reach your castle. Then, you can either send out small strike teams to harass their armies, weakening them before they even arrive, or dispatch an entire army to fight them on a battlefield. **Divide and conquer** In most fantasy stories, wizards and dragons are pictured and solitary and aloof beings. You can use this to your advantage. If the wizard/dragon is attacking your castle solo, you can counterattack with your own wizards/dragons, since you say that they are very common in this world. If the wizard/dragon is part of an army, wait for them in inevitably separate and lead a heroic solo attack on your castle. Then, overwhelm them with your troops and kill them. **Supply lines** Dragons and wizards would probably need large amounts food and wizard fuel. Instead of fighting a bloody war, simply destroy their supply lines, preventing the dragons and wizards from effectively fighting. And scorch the earth to prevent them from foraging for food. [Answer] Much of this would depend upon the nature of the air attack, and the building technology available. To survive against a dragon's flame breath, you'd need some sort of hardened roof, plus a method of ventilation to bring fresh air into the castle - flames would deplete the oxygen and heat the ambient air. A cave under the castle with a prevailing breeze would be nice, or perhaps large bellows driven by falling water with a tunnel for fresh air intake. Against a wizard... one would have to explore the nature of the damage a wizard could inflict. After all, even Saruman had to resort to conventional explosives to breach the walls of Helm's Deep. If all a wizard can do is toss fireballs (or shoot missiles in the case of Tim the Enchanter in Monty Python/Holy Grail), then the same reinforced roof and ventilation system should suffice. Defence against both... has anyone ever considered shooting flaming balls in return? Fire was one of the more potent pre-explosive weapons. True that dragons can breathe fire, but their wings are fairly thin, and probably vulnerable to flaming tar. Same goes for a flying wizard, their robes do look rather flammable. This opens up a WW2 style image of dragons spiraling down with a wing in flames. I doubt the Lord would be concerned with the appearance of the castle, if they were faced with a new form of attack. They'd just be leaving a good looking castle to whomever defeated them. [Answer] I wondered about this while playing Morrowind, where Levitation is a very easy spell to acquire yet there are still forts and castles. Then I realized that defenders could cast Dispel at any invaders that tried flying over the walls, which would likely lead to them plummeting to their deaths. So with good anti-magic the walls are still useful. Against dragons, I suspect the tried and true movie favorite, the ballista, is the answer. But it would benefit from a few improvements. The main issue is that if the dragon attacks the crew they have nowhere to hide and they typically die. I would put a bunker of sorts within a few yards of each ballista. I would also make a point of having many ballista, so while one crew is hiding, other crews can be lining up their shots. Another way to deal with dragons is for a wizard to cast Paralyze. [Answer] Borrowing an idea from one of my favorite videogames, use glass shrapnel. Make a ballista with a wider launching bay, and fire glass panes out of it. The glass will shatter on impact, causing a bad day for any wizards or dragons unlucky enough to catch a direct hit. You can also use a modified bellows pump to build pressure in a vat of boiling oil, and then squirt it at anything that comes near. [Answer] If magic & dragons are somewhat common then Castles become not just defensive positions but can also be offensive positions as well. Power projection ...Castles built on frontier to push forward your mages power ie put their magic in range of neighbour countries forts/castles & cities. A line of Castles reinforcing each other with overlapping areas of magic bolstering & amplifying each other ie magic from neighbouring towers able to be channeled to tower/s under attack, also in depth defence with another line of towers behind the first ready to channel to the front line. Magic used to attack walls? Well the walls are inbued with magic wards as a passive defence, but also defended by a company of Wizards. Aerial attack by dragons, griffins, angels, birdmen, giant eagles, pegasus riders etc a thing? Well just include a squadron or two of dragon-riders, squadrons of griffin & pegasus riders, and companies of birdmen, angels etc. Your castles become like stationary aircraft carriers. With a bunch of air forces on your border you have a good deterrent to any would-be enemy. If they attack at any one castle or section of castles you are able to do the same from your unattacked positions. No more breaking just one castle then entering kingdom to pillage, they'd have to go at every castle on border at once ...plus if you have defence in depth & castles/airforces all over distributed then wars of conquest become much harder. ]
[Question] [ In my world (essentially playing in the late 1920's to early 30's, though with a bit of hand-waved technological and political progress), a rail line exists that spans Eurasia from Lisbon to Bangkok. Most segments of the tracks are either completely straight or only bent in a very minimal way, so there wouldn't even be a need for the train to be articulated to a great extent. I'd imagine the trains that run on these tracks will probably have to travel in excess of 200 km/h to get anywhere on a reasonable time scale. The [Mallard](https://en.wikipedia.org/wiki/LNER_Class_A4_4468_Mallard) is, to this date, the fastest steam locomotive ever built, having gone about 203 km/h (126 mph), though I've been wondering if it's possible for a steam locomotive to go even faster, or if there's a physical/structural limit to their speed- Steam turbines are an option as well (like on the [PRR 6200](https://en.wikipedia.org/wiki/Pennsylvania_Railroad_class_S2)), but I'd really love to include [connecting rods](https://en.wikipedia.org/wiki/Connecting_rod#/media/File:Walschearts_valve_gear.jpg) for their design, if possible. Diesel engines aren't part of the question though. [Answer] For steam locomotives, the limits of speed are affected by mass, friction, aerodynamic drag and power. As stated in the question, the Mallard was the fastest steam locomotive, and it achieved this by virtue of its streamlining. The PRR 6200, as a steam turbine driven locomotive was not much slower than the Mallard, 110mph/177kph vs 126mph/203kph, and it was not streamlined. Apparently, it suffered from the disadvantage that its steam turbine was directly coupled to its wheels. Extrapolating from those two locomotives, a streamlined steam turbine locomotive with a 2 or 3 speed gearbox, or an electric drivetrain could conceivably exceed the Mallard's speed record, though I would not expect speeds to exceed 150mph/241kph under light, streamlined load conditions. With weight-saving measures such as titanium construction and an emphasis upon lightness for the entire train, speeds of up to 175mph/281kph may be achievable. The problem with steam engines is that they require large quantities of both fuel and water. By making the steam turbine a closed-loop system with a condenser, the necessary mass of water can be reduced considerably, and by using fuels such as heavy fuel oils, the mass of fuel can be reduced, as well as eliminating the need for both a fireman and a driver. Reciprocating pistons have the problem that they suffer from vibration at speeds other than that for which they are designed, which causes mechanical stress and limits top speeds. However, even with a geared or electric, closed-loop steam turbine, streamlining and titanium construction, I would expect a locomotive on a regular passenger service might typically reach speeds on the order of 150mph/241kph. [Answer] You have a few assumptions here which are very much based around normalising current infrastructure. There are a few things you might need to reassess. > > and if there's a physical/structural limit to their speed > > > The limit on train speeds has much less to do with the train than you'd think. The main limiting factor for trains, since before Mallard, has been track quality. In the UK, [Intercity 125](https://en.wikipedia.org/wiki/InterCity_125) trains never ran at 125 mph in normal service - average speeds were always under 100 mph, a speed which the existing Deltics could already achieve, because the track wasn't smooth enough for them to run any faster. [Wider gauge tracks](https://en.wikipedia.org/wiki/Broad-gauge_railway) would certainly improve that, of course. There's a good reason that Brunel set a 7ft gauge on the [Great Western Railway](https://en.wikipedia.org/wiki/Great_Western_Railway), and many current high-speed routes use wider gauges. > > so there wouldn't even be a need for the train to be articulated to a great extent > > > Again, track is your issue here. You're grossly overestimating what "straight" means. Sure, your trains wouldn't need fancy tilting rolling stock to take corners fast. But you'd still need multiple carriages with articulation between them, because there's a limit to how straight and level you can fit rails, and how straight and level they will stay over time. You could maybe make them a bit longer, but not significantly more. Regular railway carriages in the UK are 60ft, whereas the Shinkansen carriages clock in at 82ft. Bigger, but not dramatically so. > > Id imagine the trains that run on these tracks will probably have to travel in excess of 200 km/h to get anywhere on a reasonable time-scale. > > > Now this is your big assumption. Before jet passenger flight became common, "a reasonable timescale" was simply as long as it took, because there wasn't an alternative. Sleeper trains were the norm for any kind of long distance trip, and you just planned for however many days it took to get there. Russia still runs trains through Siberia, and Australia still runs trains across the Nullarbor Plain. The fact that it takes a few days to get across a continent is not exactly a limit. [Answer] ## Your problem would be operating economics The thing with a steam locomotive is that "an hour on the track is an hour in the shop", even at conventional speeds. Given that *Mallard* didn't survive its record run completely unscathed, the rigors of such high-speed running would take a toll on just about *any* steam locomotive design to the point where the economics of maintenance would favor just about anything else for regular high-speed revenue service. As a result, you'd probably see mainline electrification on such a line as soon as someone ran the numbers on how much they were spending to maintain their locomotives, as well as the increased track maintenance costs that'd be caused by the quite severe pounding loads associated with a steam locomotive. ## Why not steam turbines? While steam turbine locomotives existed back then -- these units used a direct-drive or single-speed geared system, sometimes with intermediate crank arms in the drive mechanism as well. This made them very steam hungry at low speeds, and the fine mechanics of a steam turbine would not help the topic of maintenance costs either. ## Electrification was *already* viable then This leads us to the solution that was already in play then, and what modern HSR above the 125mph/200kph mark almost universally uses as well: *overhead electrification* with AC power. The 11kVAC 25Hz [New Haven electrification](https://en.wikipedia.org/wiki/Electrification_of_the_New_York,_New_Haven_and_Hartford_Railroad) had already been in service for two decades at that time, and the performance benefits of not having to drag a generating plant around with your train were well-known in the art even then, with the Pennsylvania Railroad installing a similar 11kVAC 25Hz system in what is now the Northeast Corridor at that time. ([That PRR electrification](https://en.wikipedia.org/wiki/Amtrak%27s_25_Hz_traction_power_system) is still in service *today* with some minor upgrades and plant renewal over the years -- the only reason it's not capable of 150mph+ operation "as is" is due to catenary tensioning issues.) Electrification has other benefits as well. Electric traction eliminates pounding loads, and also makes *multiple unit* operation eminently practical, where the traction motors and controlgear are spread throughout the coaches instead of being all in a locomotive. This also plays nicely with the notions of streamlining that became popular in the late 1920s and early 1930s, based on early wind tunnel work and the development of the Jacobs bogie that improved high-speed dynamics greatly. [Answer] #### Disclaimer: The answer from Monty Wild covered the mass optimization part, except for the fuel. Others have also answered with stuff about rail quality issues etc. and I have nothing to add there. That being said, there is one more technology path that could be well worth exploring. ### Going nuclear Lets fit a nuclear reactor on your train. * It will provide all the heat you could ever want * It will get rid of the necessity of having a huge haul of coal attached to your train. * Also since you will directly use the steam, you don't need to concern yourself with converting the steam to electricity. * As an added bonus you will get rid of having several shifts of coal-feeders(or whatever the term was) and will instead have just few engineers making sure the reaction stays nice and tame. But what about the radiation? Won't the shielding prove heavier than the coal? In 19th century we didn't care all that much about stuff like that. So just add some lead plating around the engineers outpost and call it a day. Who cares about a teensy bit of radiation somewhere in the deep wilderness? [Answer] No way can say, "The top speed for a steam locomotive is X kph." It depends on many factors. If you reduce the total weight of the train while keeping the power of the engine the same, then it will go faster. Add better streamlining.Reduce friction between wheels and rails. (Though frankly, this is a pretty minor factor with trains.) Etc. Can the power of the engine be increased without increasing its size and weight? Probably. I'd be reluctant to say that any technology has reached its absolute maximum. But a lot of work went into steam engines so my guess -- and it's just a guess -- is that without some radical new idea, they're probably near the maximum achievable. If you're writing a fiction story, you don't have to actually provide design specs for your improved train. And indeed most readers would be bored out of their minds if you did, especially if this is not a key element of the plot. How fast do you think your trains need to be? If you said they travel at 200 kph, I doubt any reader would question it. If you say they travel at 1000 kph ... yeah, probably not plausible. [Answer] So, there are multiple factors in the history of modern train development which you are mostly missing with a single engine. * Breaks. It was established quite early, but breaking on the wagons and not only on the engine might require manual labor – or better hardware. * Refuelling and refilling with water – you need many stops for a steam engine. * A limit to the power of a single engine: you can make a single engine only that powerful and only having so many weight (to be able to pull many wagons behind it). * A corollary: the amount of weight a wagon coupling system can allow. * Air drag (as mentioned above, all that streamlining). The solution to many those problems are either powered wagons (in passenger trains, which are basically all electric) or multiple engines. In both cases you (basically) need to control multiple engines as a single one. This is, however, not viable before some electronic control system. It might be a quirk of our technical development, but by the time we (as humanity) could reliably control multiple engine units in a train, we had electrical / advanced diesel trains. Why am I talking about power and number of wagons? Because if you want to accelerate a train to a higher speed, you need pull power and braking ability which you basically could use to pull more wagons at a lower speed. (It does not convert completely, but it's the same direction.) Next requirements are the economics: Why do you want to pull the trains so fast? * Cargo ain't the reason. * Passenger trains could just spend a further night without much ado. * If it's really urgent, they could just cable the message. Or fly (if flight is in the picture already.) Also, if you follow the [Transsib](https://en.wikipedia.org/wiki/Trans-Siberian_Railway) route for a while, it had some problems historically. It was not easy to build with all the bridges and tunnels. So, it's again the elevation and load limits to the trains. [Answer] Oh, let us have some fun with this... First, you simply are not going to get the entire route straight and flat - not with engineering of the time, or close. That means there will be sections needing a different sort of engine than for the fast runs. You might switch out just the engine, or switch trains. Still, there is a lot of fairly flat geography. Given enough(!) human determination, there could be some very long fast stretches. Also you need to keep the rails very near exact in alignment. Given that ground can shift, this means a need for periodic re-alignment. To my mind this means a simple (hah!) mechanical gadget that runs along the rails, adjusting alignment. This is screws and wedges and a human watching an optical sight, so feasible for the time. (Yes, there would be cost.) As others had noted, wider gauge is good for stability. As other posters have noted, there is great advantage to an external power source. But electrifying the entire route seems improbable. Mechanical gearboxes are going to be a problem - so use electric motors instead. There are motors and generators from that period still in service, so reliability could be good. This means a steam turbine fitted to a generator, and the wheels driven by electric motors. Efficiency is a concern, but if we imagine rare-earth magnets available early (not a huge stretch), then this is feasible. The Japanese bullet trains were built in the 1960s, so not huge gap from your time period. Would not be surprised if you could get equivalent 200mph speed. Train would have a streamlined nose, much like present bullet trains. Powerplant would be a steam turbine, driving an electric generator. When leaving station most power would come from electrified rails, and perhaps for tens of kilometers after. This reduces peak power requirements, and greatly stretches the on-board fuel. Might be electrified sections in more developed areas. Likely want something near a closed-loop to reduce water carried. Lots of air flowing past a fast train. Back end of the engine would be huge radiator with aluminum fins parallel to airflow - figure the last 10-20 meters of the engine sides as a stack of fins. (There are similar designs from the period, so not a stretch.) Could such a thing have been built in that time. Maybe not, but also not so far from possible. :) [Answer] There are a couple of inherent limits to the speed of a steam train, though I've not done the maths to work out the exact numbers. Firstly, no steam train has ever been fitted with a gear-box, (mainly due to the size/weight that would be required to handle the load). This means that at top speed, the pistons are reciprocating at VERY high cadence - significantly increasing that cadence requires numerous major changes. Secondly, the very concept of steam power relies on the *expansion* of the steam, which involves diminishing returns, basically the faster a piston "opens" the lower the force that the steam can exert. And increasing the steam pressure also produces diminishing returns... To contradict certain other answers, the amount of water needed isn't a major factor. From what I can find, when Mallard did its record-breaking run, it only had seven coaches in tow, which is well below its limit, giving a total of approx 240 tonnes. The tender had a maximum water capacity of 5,000 imp gal / 23,000 L; == 23 Tonnes - less than 10% of total weight. ]
[Question] [ Assume there was a super advanced alien race that for some reason, wanted to add a new planet, of lets say 1 Earth mass, into the Solar System. Where in the inner Solar System *(The part of the solar system inside Jupiter's orbit, so asteroid belt is included)* could we put this planet, so that it would have a stable orbit for billions of years? *Note: I would preferably not want have this planet orbit closer to the sun than Mercury, and would like for it to affect the inner planets as little as possible, although I care more about the first condition rather than the second.* *And also, the planet needn't be habitable* [Answer] There is a book about the possibility of human habitable exo planets around other stars. *Habitable Planets for Man*, Stephen H. Dole, 1964. <https://www.rand.org/content/dam/rand/pubs/commercial_books/2007/RAND_CB179-1.pdf> On pages 46 to 52 Dole writes about the spacing of the planets in the Solar System as it was understood in the early 1960s. Dole estimates that the forbidden zones around the planets take up ab about 50 percent of the volume of the Solar System, leaving about another 50 percent which might possibly be occupied by other planets under some conditions. According to Dole's calculations, the more massive the planet, the larger its forbidden zones, and the farther the planet is from the Sun, the larger its forbidden zone will be. And the more eccentric the planet's orbit is, the larger its forbidden zone will be. The mass of the star is also a factor. Table 8 on page 50 gives the inner and outer edges of the forbidden zones of the planets. As nearly as I can read the tiny numbers in the table, the gaps between the forbidden zones are wider than the forbidden zones for the inner planets. Figure 18 on page 51 indicates that there is room for a roughly Earth mass planet and its forbidden zone between the orbits of Mercury and Venus, between the orbits of Venus and Earth, between Earth and Mars, and beyond Mars. It might be possible to put two Earth mass planets and their forbidden zones between Mars and Jupiter. None of the forbidden zones overlap, except for those of Neptune and Pluto, and the orbit of Pluto is tilted considerably compared to that of Neptune. I note that it would be unlikely for major planets to form with orbits where their forbidden zones overlap, because those overlapping forbidden zones would interfere with he formation of the planets out of smaller objects. But if aliens build a new planet in our solar system by using spaceships to move smaller objects into place and assemble a planet out of them, or if the super advanced aliens open a portal to move an already formed planet from a distant star system to an orbit among the already formed planets in our solar system having partially overlapping forbidden zones might not matter much. [Answer] Make Mars a double planet. Or Venus, or of you do not care about Earth much, replace the Moon with the planet. The previous stability should remain more or less the same, apart from some disturbances that might or might not manifest in the long term (as long as the resonances remain stable, you do not have much to worry about). [Answer] If you have the resources to create or bring a new planet - generally, wherever you feel like. You will be probably able to maintain the orbital stability as well. On the other hand, if you are limited in long-term expenses, the orbital stability becomes an issue. And there, the answer becomes "nowhere in the habitable zone". Mercury, Venus, Earth and Mars are in a complex orbital relationship, maintained by constant exchange of momentum between the planets. There are hints that the solar cycle is related to the tides the first 3 planets exert at the Sun as well. How can one save the plot, then? * Replace Venus / terraform Venus. It is Earth-mass and with some added water and without the greenhouse effect can be pretty much habitable. And only slightly hotter than the Earth (if at all). * Make Mars double. Mars is not much different than the Moon in both mass and composition. Put an Earth-sized planet there and allow Mars to orbit around. A heavier body in the place of Mars will likely have only minor effect on the Earth's orbit. The two Mars moons can be put in an orbital resonance with Mars (3-moon world?), mined into oblivion or stored in the asteroid belt until better ideas arise. * A combination thereof (replace Venus, store Venus near Mars where it can cool off for a while). Beyond Mars it's rather cold, but if you don't mind that, the asteroid belt itself is a place. Not a place to have a planet on its own, but pretty much a place where a planet would be stable. Vacuum it first or prepare for a serious meteorite shower later. You can use the collected material for a little fancy moon as well. Beyond the asteroid belt it is really, really cold, in particular too cold for almost any type of atmosphere or hydrosphere. If you can bear the heating bill, neither Jupiter, nor Saturn, nor the ice giants beyond, will mind an Earth mass satellite. You will have to rearrange the moon zoo there first in order to avoid crashes. Don't put anything heavy below Venus orbit even if you don't mind the heat. We like our calendar and seasons pretty much. Thank you in advance. [Answer] The planet would be able to be the most stable in a orbit between earth and Mars because that the biggest gap between notable celestial bodies of the inner solar system. So gravitation pull of any bodies would be most minimal hence being able to keep a steady orbit as long as the sun lives. Edit:I apologize by I messed up(dyslexic). It rather crowded between mars and the belt you best bet would be between earth and mars. Another solution would to have an orbit perpendicular of all the other orbit since most bodies in this system tend to stay on one plane. [Answer] This is a cool question. The short answer is: probably not. The long answer requires us to consider a few things: ## 1. Are the current planets stable? To discuss this we first need to understand something about dynamical chaos. Let's imagine a situation where you're trying to predict whether a skilled soccer player will make a goal. Furthermore, let's say you're a particular enterprising soccer fan and consequently you know the direction they will kick and the power of kick with some accuracy. In addition, you measured the goal beforehand and know what its boundaries are. If you know all these initial conditions precisely you could simply run a simulation to predict the position of the ball over time and determine - for certain - whether the player makes the goal or not. Now let's complicate the situation: instead of knowing the initial conditions perfectly, say there is some error. If you conduct your simulation in this case you'll find there are some cases where the ball ends up in the goal, and some cases where it does not. Even if we know exactly how to do the physics, Even if our simulation is perfect, the position of the ball at any given time in the future will be uncertain simply because the initial conditions are. The solar system as a whole exhibits something called chaos, which, at the risk of oversimplifying, is fundamentally just a version of this same effect we found with the soccer player. The difference is that in the case of chaotic systems the error in a subsequent state grows quickly (typically exponentially) in time. Hence, dynamical studies of the solar system typically involve comparing large sets of simulations statistically - while we can't be confident in any individual simulation - the overall ensemble is interpretable! [![enter image description here](https://i.stack.imgur.com/7d3Rp.png)](https://i.stack.imgur.com/7d3Rp.png) Below is a plot from a paper by [Laskar, J. & Gastineau, M.](https://ui.adsabs.harvard.edu/abs/2009Natur.459..817L/abstract) unfortunately behind paywall. They integrated identical copies of the solar system for 5 billion years with the only difference being that they shifted initial position of the planet Mercury by just a few meters between simulations. The plots show the resulting maximum eccentricity of the Mercury over time (first panel is using just Newtonian mechanics, and the second panel is using General Relativity). In either case, there are many cases where the eccentricity of mercury can grow extremely large, and most of these cases result in either ejection from the solar system or collision with another planet. This implies that the current planets - just the 4 we have - aren't super stable as is. This isn't to say that the solar system will definitely shake itself apart - but it does show that the unstable trajectories are possible given what we know about the current state of the solar system. ## 2. Alright, but what about adding another one? If we wish to consider the addition of another planet, what's critical is its mass. If the new body has a small mass, it won't really destabilize the orbits of the more massive bodies, and it has a better chance of surviving. There are regions like this in the solar system - for example the "Earth-Mars Belt" (you can read the paper [here](https://arxiv.org/abs/2010.01225): since it's public), a region between ~1.09 and ~1.17 AU where small bodies might be able to survive for billions of years. Finally, we get to your case - what if the added body is the size of the earth? In this case, the body not only needs to survive, but it also has to do so in a system that is being destabilized by its own (earth sized!) gravitational field. Given that the solar system without such a body is barely stable, the addition of such a large body would almost destabilize the entire inner solar system - probably impacting another planet or being ejected. While the only way to find out for sure would be to run a ton of very time-consuming simulations, I'd be very skeptical that such a situation is possible. ## 3. What about resonances? There are some situations where planets can be found in what are called "Mean-Motion Resonances" with each other, and this tends to permit stability even in very closely packed systems. The poster child for this type of behavior is the Trappist-1 system, which exhibits several small planets all in resonance with each other. While such a configuration cannot be realized by simply adding a planet to our solar system - it is conceivable that there could exist systems in general with planets more tightly packed than what we have. \*\*This answer is reproduced from a similar [question](https://astronomy.stackexchange.com/questions/50292/could-a-planet-theoretically-have-a-stable-orbit-between-venus-and-earth-or-eart/50326#50326) on the Astronomy StackExchange ]
[Question] [ I was reading [James Blish](https://en.wikipedia.org/wiki/James_Blish) again the other day and came across a passage wherein he suggested, with all seriousness, that the only article required to create a new age of piracy was ships that didn't require fuel. It further suggested that the only reason the [Golden Age of Piracy](https://en.wikipedia.org/wiki/Golden_Age_of_Piracy) happened at all was that sailing ships needed only the wind to take them and that the age ended because steamers needed fuel. I've seen others suggest that as long as you have lawless ports where you can fence your stolen goods *that* is all you need for piracy to run rampant. So I decided to look at the actual history of piracy these are the four factors that seem, to me, to have led to its rampant heyday: * The crews, there was a ready supply of the skilled but desperate, both at sea and on shore. * Ships that could sail long distances, especially compared to the distances between ports, without making port and when they did "port" for anything but the most strenuous repairs could be any sheltered bay where clean water and food could be found. * Ships that when they did need major repairs could be serviced with relatively cheap, and abundant materials. * Goods (in coastal towns) and cargoes (on other ships) to take and ports to sell them in. With those factors in mind I'd like to consider a case study, towards the end of the Federated Human Space timeline. There are three basic phases to the future history in this universe: In the first few decades of our expansion into space the authorities were very free with what left Sol and many colony worlds with cutting edge technology were planted in [far flung star systems](https://en.wikipedia.org/wiki/Canopus) that have rarely been heard from since. After humanity met their only extraterrestrial neighbours they took to something of a war footing, expansion slowed and a very successful program to limit the rate of colonial spread and technological advancement was put in place. The Continuity Program aimed to keep technological artifacts interchangeable across Federated Space and as far beyond as possible and to keep human populated star systems as densely packed as space allowed in case they ever had to defend the colonies from their worryingly reticent neighbours. As part of the program they keep the production of many vital components centralised and they took pains to round up ships that had been retired so they couldn't be captured and studied by their possible adversaries. Fast forward to the era after the Sunderer Crisis and Continuity still keeps a lid on humanity in many arenas, though for very different reasons, but there are several hundred decommissioned/mothballed hulks in the inner systems (those star systems within 15 Light Years of Sol) alone, and there has been substantial skill leakage out into the colonies, many parts of those hulks can be reused, and ships built from scrap have become viable. The situation as compared to the Golden Age of Piracy factors I have identified are as follows: * Starship crews have become a breed apart from their planet bound cousins, their opportunities are constantly growing but there are also always ventures that go belly up leaving a few rogues haunting the watering holes of docking stations looking for work at any given time. Crews tend to pull together in times of trouble but they also have a certain fierce rivalry to the way they conduct business as usual. * The ships in the setting do have comparable relative ranges to those at the height of the [Age of Sail](https://en.wikipedia.org/wiki/Age_of_Sail) in terms of being able to run between several ports without any need to resupply and they don't need any kind of port except when they need major repairs. * Most of the materials needed to service starships are now readily available in a number of places outside direct government control, along with those with the skills to use them. * Cargoes exist that can be taken with relative ease in transit. Much of the trade is in raw bulk materials, mostly pure element stock for molecular printers, value added goods like art, alcohol and fine weaving whose value is in the fact they are made by hand or that they come from a certain place, and large scale integrated systems like interplanetary ships and space habitats. Of those goods the most easily stolen are the elemental stock and the integrated systems but all can be sold on if they can be moved far enough fast enough, which usually they can. The equivalent of shore raids in space probably involve hitting habitats and are probably (read certainly except under very strange circumstances) impractical. **So does the situation after the Sunderer Crisis support the idea of space piracy?** In answering please consider both raiding ships for interstellar cargoes and the raiding of in-system shipping by local vessels. Additional data that may be useful: * The average travel speeds are roughly 4C but the specific travel time for any given trip is highly unpredictable. * Travel is completed using jumpdrives in increments of 5LY or less per jump to maintain an acceptable level of unpredictability, longer jumps are less predictable and prone to larger deviations in jump time. * While in jump the ship and its crew experience no time, the trip is instantaneous for the travelers. * Because of the nature of the jumpdrives in use interstellar ships tend to be as big as the support facilities on their design consideration route allow, topping out slightly south of 50miles long due to one particular facility being standardised to that size. * By the era being discussed humanity is still concentrated in the inner systems, three jumps (15LY) from Sol, but has successful colonies in the trade route network out into the 25-30LY band. * There is a [reactionless drive](https://en.wikipedia.org/wiki/Reactionless_drive) effect as a secondary function of the jumpdrive technology but that function can't be used near large masses, including but not limited to planets, moons, most asteroids, the drive cores of other ships and most of the larger space habitats. [Answer] **Highly Unlikely** In the real world throughout history, in order for a vehicle to get from point A to point B it must trace a continuous path, direct or otherwise, through three-dimensional space between the two points. If trade winds, land masses, mountain ranges, clouds of volcanic ash or hostile territories limit the possible routes, then a "pirate" can predict the path and attempt an intercept at some point outside of the direct control of the protective forces at the departure and destination points. The huge difference in this situation compared to real world travel is the jump drive. Now the vehicle can avoid all the risks associated with the path in between point A and point B completely. The only "real world" space it needs to traverse is to a safe jump distance from planets, habitats and so on. (It was only specified that there was a proximity limitation for the reactionless drive, but if there is no limit on jumping close to other masses then raiding habitats is very likely rather than the opposite.) What this means is that a port governing body only needs to focus on controlling its local space out to the safe jump radius, whether that is the "100 diameters" rule from the Traveller roleplaying game or some other distance. The governing body does not even need to control the entire sphere (although it's probably a good idea), it just needs to provide a small number of protected corridors between the cargo transfer stations and the safe jump distance. Basically stick a few heavily armed battlestations orbiting just outside safe jump distance and direct outgoing merchants to head towards one for its jump point. (Also maintain a constellation of observation / early warning satellites and mobile forces.) The second huge defence against piracy is Newton. Spaceships are totally unlike craft that travel on land, sea or in the air, because their speed is not constrained by a surrounding medium. Spacecraft hurtle through space at mind boggling speeds that our human minds have difficulty grasping intuitively, but outside of when they are boosting to orbit they typically have quite low acceleration compared to Earth-side vehicles. For maximising movement through the vacuum of space, what matters much more than peak thrust is total delta v. A craft may only be able to accelerate at 0.01 G, but if it can maintain that acceleration for 50,000 seconds then it has 10 times the travel potential of a craft that can accelerate at 1 G for 50 seconds. So even if the pirates have long range weapons so it is a credible threat, pirates cannot just tell a ship to "stop or we'll shoot", because "stopping" will probably take hours or days. Instead, pirates need to close in with a target, match velocities and dock. (Even if it's not needed for artificial gravity, spinning a ship on its axis is a really good way to make hostile docking attempts really difficult.) They cannot do this unless their ships have vastly better acceleration than their prey, which is not likely for "mothballed hulks". They want to be really, really careful, because apparently most of these ships are 80 km long, which means the energies involved are massive but they also need to really, really quick so the navy can't respond to the calls for help and intercept and/or track them. ("Really quick" means taking only a day or so to match velocities after entering the detection range of the target on a vector that clearly indicates that they are up to no good.) TL;DR - provided that destinations have defensive forces to control local space, jump ships are practically immune to attack. In-system craft are really difficult piracy targets unless the pirates have vastly superior acceleration compared to their targets. [Answer] With your conditions I don't think widespread piracy would be feasible. Too easy to escape and no way to ambush goods carrying ships, as they can immediately jump in any direction. That way only - though still remote - possibility is in-system piracy, but this would be much too easy to interdict by local authorities. In the age of sail the pirates were operating either along trade routes or at specific choke points. The reason for the former is that ships carrying cargo and/or passengers need to get from point A to B as fast as possible, especially since they weren't fast. This was due to the limited capacity of consumables, especially food and drinking water. If any of these ran out or trip was prolonged, everyone was in serious danger. While I was doing research for different topic (transport in slave trade), I was kind of shocked that average mortality on average cruise was 8% for free passengers, 15% for slave trade. Normal cruise was usually eventless with no deaths (or maybe one or two of the passengers or slaves succumbing to conditions), but every so often a disease broke out or trip taking longer caused food rationing or shortage, causing in turn mass casualties (up to 50%-60% of people on board, passengers and crew alike). Also, that mortality numbers included people dying while accommodating to new place or recovering from trip hardships, too, and that could be even months after arrival. So quicker the travel, the better, but of course that means geographically it will be along very specific route and with obvious destinations it's even more predictable. At sea there's really no way to disengage from pursuing ships if 'they're faster; in deep space - as mentioned - one just jumps away in random direction. There's literally no way to ambush someone en route. Choke points are obvious as well - one can see it even today in piracy in the Malaya area or Gulf of Aden (with Somali pirates), but even in Gulf of Oman (though this would be rather state piracy). In general, even today piracy exists and it's basically because merchant shipping is severely constrained in what defensive measures they can deploy (by laws of country they fly the flag). Though there are always options like Convoy Escort Programme Ltd - private navy, offering escort through "pirate infested waters" for a fee. So, going back to your question, none of this will apply, except barely for choke points (which would be any sufficiently large mass like moon or a planet or other ship), unless you force all the interstellar traffic to be constrained to, say solar plane of ecliptic. There is literally too much space to cover and people do not realize how BIG space is. This, of course, works for in-system piracy - locals raiding ships and then go into hiding in an asteroid belt, but there's one serious drawback to it - you can't really hide in space. Even mediocre telescope is AWESOME in space, and really just minor investment in basic surveillance net would at the very least detect such acts (of course with all the drawbacks of STL of imagery), giving enough to local authorities to pick up the trail. Main reason is that range is not really limited, and with high enough resolution every object in solar system, even quite small, can be detected and tracked. And raiders would have to invest heavily in countermeasures, and this is definitely not something that could be cobbled in an asteroid mine's workshop... Same visual detection systems can be mounted on every ship, too, and unless you're introducing some kind of FTL sensors, merchant detecting incoming ships from really long range and can, by doing very minute course corrections, avoid intercept long enough to be able receive support. [Answer] Another thing that limits piracy in this setting that a 50 mile ship (assuming it's mostly cargo space) **will take years to unload of all it's cargo at best**, let's say for the sake of argument that the 50 mile ship is only 1 mile wide and 1 mile tall (50to1 ratio is extreme). A standard shipping container is 8 feet wide, 40 feet long and 9 feet 6 inches tall (and if the cargo is outside containers it will take much much longer to unload), this means that means that there can be a total of 2417580000 if the ship is 100% containers, even if you say 50% of the ship is used for things other then storage that still comes out to having 1208790000 (1.2 billion) containers on board that the pirates will need to unload, seeing how the entire world containers are estimated to have [170 million containers](https://porta-stor.com/many-shipping-containers/) I'm pretty sure that if someone **stole 10 times the entire world shipped goods** he won't have the years needed to unload it all before the multiple worlds who had their entire economy stolen will come hunting for him gun blazing. [Answer] > > Does the situation after the Sunderer Crisis support the idea of space piracy? > > > ## No it does not: ### 50 mile long ships is your biggest limiting factor While Jump Drives could be handwaved away with some manner of jump inhibitor technology, 50 mile long ships utterly destroys your "The crews, there was a ready supply of" and "Ships that when they did need major repairs could be serviced with relatively cheap, and abundant materials" criteria. Part of forming a pirate crew means recruiting enough lawless people without attracting the eye of law enforcement, and part of a ship being cheaply repairable means that you don't need to bring in a lot of outside labor to fix up your ship. One of the biggest factors in why the age of piracy was so successful was because a pirate ship could be small and cheap and run by a small crew, with minimal skills, on a small budget. This means that pirates did not have to start off rich to get started. Rich people have no reason to invest in something as high risk as piracy. A man-made object the size of a 50 mile long ship would take hundreds of billions of manhours just to get out of a mothballed state performing enough routine maintenance and inspections to get the ship up going. Even if you assume extraordinary amounts of automation, it would still require thousands if not millions of highly trained crewmen to oversee the automated processes to make sure they are operating to spec. You can't simply recruit that many specialized laborers for a common clandestine cause without getting yourself caught by authorities. What's worse is if you need to make any sort of extraordinary repairs. With only a few of these ships in service at any given time, even if the materials are cheap, the facilities capable of conducting repairs on this scale are very few in number... so the second an illegally operated ship shows up for a major repair, it will be instantly obvious and authorities will be notified. If pirates can't find a sketchy, no questions asked, discount port to operate out of, they will not be able to perform critical repairs & maintenance. ### But what if we handwave away the maintenance? Even if you assume a flawless automated maintenance system allowing these ships to be run by a very tiny crew... they still need the manpower to actually perform piracy. While a ship this size might operate with small enough of a human crew to stay under the radar, official merchant ships have no such limitation. The volumes these ships can haul is so ridiculous, that you could fit a million space marines and 10s of thousands of fighters/bombers on board, and barely put put a dent your profit margin. Since illegal crews like pirates have to stay small to stay covert, they would be hopeless outmatch by what an official ship going through legal channels may be able to muster. ### How going smaller is better for piracy It is better to make ships much smaller and more numerous: Instead of the old hulks just being a few hundred of these 50 mile behemoths, scale them down to just a few hundred feet, but make it so there are millions or even billions of these old derelicts floating around for anyone to get their hands on. With there being so many, no one will notice when one goes missing, and when 1 of the 10,000 ships that showed up in your planet's orbit today is a pirate, there may be hundreds of possible places for him to pull in for repairs and to sell goods, and only one of those many places needs to be unscrupulous enough to ask no questions. Even if only having 1 place able to service warp drives is important to your story, this is still okay if that 1 place has millions of docks for ships to go into for repairs run by millions of separate maintenance teams. While there is technically no reason a setting can not have 50 mile long ships and still have piracy, the pirates will be having nothing to do with those. Pirates need smaller ships and smaller prey to be successful. [Answer] ## Your best bet might be hijacking Piracy proper doesn't seem feasible in your world -- er, universe. To get the goods off a 50-mile-long ship, you're going to need another 50-mile-long ship to take it... except as you mentioned, the jump drives of large ships interfere with one another. Unless a pirate has some means of keeping their hulk "cloaked" in a common jump waypoint area, only warming up their jump drive when another ship appears (not to actually fire, but just to cause interference), they're not going to have any means of stopping and approaching the target before it jumps off again. Instead, I posit that your pirates will lurk in squadrons (probably 10-30) of *tiny* interceptor ships on the periphery of these jump waypoints. They lie in wait, and when a ship pops in, they use their vastly superior speed and maneuverability to approach and dock to the victim before they can align and jump off again. Using technology *scavenged from* the mothballed hulks, they can develop special interceptors; perhaps one is designed to interfere with jump drive operation (thus disabling the jump drive as soon as it's attached, so the target doesn't jump off while they're attempting the hijacking), while others are literal can openers that attach to and punch through the hull. The pirates then board the target ship armed to the teeth, and capture the crew. Once the pirates have control of the target, all their ships are safely attached to it and they jump off to their "hideaway" with the new ship. If they have certain morals they can transfer the crew to a smaller ship and go dump them at some backwater station... or lacking such morals they can just jettison them. With the ship safely tucked in their hideaway, they can transfer and disperse valuable cargo at their leisure, and then scavenge it for repair parts as well as perhaps any new technology they don't yet have. The best defenses against hijacking will be: * Navy patrols at waypoints: Common jump waypoints should be actively patrolled, specifically scanning for stealthed ships. Patrols should have larger ships that can legitimately challenge hulks, as well as fighters/interceptors that can chase off smaller ships. Interesting twist -- crew of a patrol doesn't feel they're getting paid enough, decide to mutiny and become pirates! * Armed crews or even security teams: on a 50-mile-long ship, why not have 20 extra people on board that just sit around playing cards with guns strapped to their backs? For they most part they're just getting paid to play cards, but if a crew tries to hijack this ship it may not turn out well for the hijackers. * Small-caliber defense turrets: automatic targeting turrets all over the ship that are small enough to track even the fastest interceptors (with perhaps a few larger turrets in case the pirates bring any bigger, better-armored ships to bear). Take 'em down before they get a chance to board. * Quarantine systems: anywhere a hull breach is detected, heavy security doors close off that area of the ship, and then the environment can be made hostile in a way that overwhelms any personal-sized protection (for example, overheating the quarantined section to 200-300°C which would likely overwhelm an environmental suit's climate controls before plasma torches/etc could break through the security doors). Might occasionally cause some damage to the ship or more rarely the loss of a crew member or two, but better than losing the whole ship and possibly its crew. * Tracking/distress beacons: more of a deterrent than anything else, if the crew activates this (or the ship activates it automatically), it summons help or perhaps passively transmits (via quantum comms or some other virtually undetectable means) its coordinates so the authorities can track the ship back to where the pirates have taken it, and shut them down by whatever means necessary. Not as helpful in protecting the crew/cargo of the ship itself, but has potential to disrupt future operations, and hopefully increase the risk of hijacking to unacceptable levels. [Answer] I think you're overlooking a few things that made pirates successful in the Golden Age of Piracy. ## Impressment It wasn't an abundance of "skilled but desperate" people. Nations practiced impressment, which was basically semi-permanent slavery. Grab a guy, make him work on a ship. He's stuck there for months, if not years, learning skills and making a wage but otherwise where he doesn't want to be. They didn't do this because there were a lot of skilled sailors around, they did it because there wasn't nearly enough. Many a pirate was a former impressed sailor. ## Trade Winds Ships sailed in fairly predictable routes because the winds were fairly predictable. It's much easier to pirate a ship if you have a pretty solid idea of where they are going to be. How will your space pirates know? Perhaps a constraint on where ships can jump? [Answer] Classical piracy is nearly impossible in your setting. Even in a setting without FTL boarding and seizing the cargo is going to be unpleasant. As I see it you got three options as pirates. ## Ransom, Infiltration and "Protection" Ransom is as easy as getting something nasty on board of one of your spacecraft. Antimatter, nukes, combat robots, nanotech, several tonnes of semtex, xenomorphes. Alternatively messing with the crafts systems (explody jump drive software update) or crew (got a cute daughter there pal) is also a vector. Be creative. You tell the company about the threat and demand a reasonable price in exchange for the information on how to remove it. Alternatively you get a crewmember to drop off some cargo on deep space. Infiltration is a long term project that might be difficult to pull of but, given the extreme payoffs, it is worth it. Place more and more sleeper agents on the vessel and wait for worthwhile cargo. Then you eat the rest of the crew or space them. Whatever tickles your fancy. The protection angle has to bee combined with occasional attacks, where you run the ransom strategy with heavy weapons or simply conduct purely destructive attacks on the spacecraft. Then you approach shipping companies with an offer of protection in the dangerous territory. The money is regularly shared out among the captains and greedy morons get crucified on their ships nosecones. There is even the option of going legal here. [Answer] **Extortion** Remember, the particular goods are not the target, the wealth is. Since getting close and at the right speed is rather improbable, change tactics. Threaten to blow up the ships. If your pirates have developed a reputation or can offer proof that they can and will destroy the ship; the crew, or the ships owner (or insurance), will pay in a crypto currency. Note: I gave a similar answer to a similar question. [Would interstellar space piracy be possible under these conditions?](https://worldbuilding.stackexchange.com/questions/210504/would-interstellar-space-piracy-be-possible-under-these-conditions/210519#210519) [Answer] Addition: as you're writing fiction, you can flaunt physics and make up your own force via some presently-undiscovered, intergalactic wind, permitting old and new piracy tactics to come alive in three dimensions! > > **So does the situation after the Sunderer Crisis support the idea of space piracy?** > > > Perhaps- This would help explain both the reactionless drive and unpredictable transfer times (tides, varying "wind" speed, etc.) > > * The average travel speeds are roughly 4C but the specific travel time for any given trip is highly unpredictable. > > > > > * There is a [reactionless drive](https://en.wikipedia.org/wiki/Reactionless_drive) effect as a secondary function of the jumpdrive technology but that function can't be used near large masses, including but not limited to planets, moons, most asteroids, the drive cores of other ships and most of the larger space habitats. > > > [Answer] **The pirates would disable their prey with long range weapons.** Long range weapons are great in space. You can see a long way and there are no crossbreezes to spoil your shot. Matte black, stealthy<\*> pirates would use railguns to hamstring their prey while still at distance. They would take out the engines and defensive weaponry. The ship could then be threatened at close range with more destructive weapons (e.g. a nuke) if it resisted. In addition to cargo, the target ship's crew itself could be a prize to be ransomed (as modern pirates to) or pressed into service on pirate ships. * seriously stealthy! [Answer] With the mechanics of your drive, I think your ships are going to be a bit different from what you think. I think they will use large cargo containers (at a mile long, they would be only 2% the length of the ship). They would arrive, establish a stable orbit, and disconnect/drop all the containers listed for this location. They would then maneuver to where the outgoing containers have been staged for pickup, connect them all, and depart. The first part might take a day, and the second might take a week. Every few dozen stop-overs, they might take a few days vacation. So piracy? There really is no point going after the ships in "flight". (You don't know where they are except when they are maneuvering to drop or pickup.) You go after the freshly dropped cargo, or in some rare cases, the cargo being staged for shipment. It becomes a race: Can the pirate get in and steal something before the cargo handlers and guards can arrive and establish control. I think there is one cargo you've forgotten: Colonists. I don't think this changes anything. [Answer] At first, I was thinking a 50 mile long ship would be outrageously too large. Shipping of standard raw materials, such as what you would find on a periotic chart, would be unnecessary as these materials would be available in most systems already. However, if these far flung systems produced or harvested exotic forms and kinds of matter, which may be doable. If one of these systems harvested pure neutrons from a neutron star to be transmuted to any element you want, such as super trans-uranic elements, you may need large quantities of liquefied neutron matter. Another, is either harvesting or constructing sub-stellar black holes. These things you do not want to create in Sol. If you ended up dropping one out of its construction containment, you do not want it bouncing around the Sol star system. So build these babies in some disposable star system of the frontier. To make Alcubierre drive like system, you will probably need black holes to power them. Now, based on your limitations, you can’t just go from one of these harvesting site, up to 30 ly away from Sol, you can’t do it in one jump. You would need to make more than 6 jumps. More than likely, these jumps would jump to star systems along the way, to allow the jump drive to cool down or recharge. Can’t imagine subjecting this powerful drive to such huge stresses be good without giving it time to stabilize. The drives that power these freighters are so powerful that their power interferes with other freighters. Other objects, such as planets, the star itself etc. will cause issues for these ships. They must enter these systems from a great distance, maybe 100’s of Au out and slow approach the pit stop areas for recharge. These cannot be too close to the jump point so it will take some time to transit in and out of star systems. These jump points will change over time, due to the orbit of planets and the movement of the stars, but is very predictable. Economies would develop around some of these common pit stops these freighters travel through. In our part of the galaxy, there isn’t many star systems spaced out enough to select any number of systems to choose to jump to, maybe one or two along common routes. Limited and predictable routes are more likely to fall prey to nefarious people to try to take advantage of. Now, the biggest problem with the reality of this universe is time. To make a transit from one of these far flung colonies, 30 ly out, is 7.5 years one way, not counting porting time. Cant imagine you have a professional and skilled crew if they will be away from family and friends for 15+ years. So the “crews” will probably be much larger to account for the crews families. Due to socio-economic balance, the shipping company may make these large long haulers into cities. May forgo some automation to justify a couple thousand people on board as “crew.” They bring their own economies with them that need servicing and cash into pit stop stations. This can make them more desirable as a soft target for pirates. A small pirate clan may not be able to deal with a 50 mile long ship, not to mention can do anything with liquefied neutron matter, but if they threaten the lives of the crews children, they may be more apt to cooperate or maybe holding the ship/crew hostage. Plus, these large crews can add to the number of desperate space sailors that may be more inclined to go on raids for quick cash. ]
[Question] [ Post-apocalypse how well would photo-voltaic solar cells hold up? They are solid state so I expect they would do okay for a while, but would they remain functional for 100+ years. I know that dust and grime would stop exposed arrays functioning, batteries will rot and that inverters and smart meters are prone to failure, but would old cells be able to be reconditioned and put to use? Would scavengers be able to find rooftop solar arrays, or would they need to find sets that for some reason were never installed and kept in safe storage? [Answer] There are three big problems and one that is far less serious. One, encountered by a Peace Corps volunteer I knew who worked in the Sahel region in Mali, and also brought to my attention by someone who had been a U.S. consul in Tanzania, is that photo-voltaic cells are theft magnets in places where there is lots of extreme poverty. It is a form of wealth that cannot be hidden if it is to do its job and can't be carried on your person. Efforts to install them to run village well pumps would generally fail unless a 24 hour guard crew was assigned to protect it by the village. Post-apocalypse, I would expect that similar concerns would arise. A second is that photo-voltaic cells usually have fragile glass panels incorporated in them and aren't that sturdy at the silicon level either. While they don't have moving parts - yay! - any decent hail storm, hurricane, or dust storm vigorous enough to stir up gravel is going to do a lot of damage. Even a proximity too close to a nut or pit-fruit bearing tree could be a problem in the presence of severe windy storms. High winds can rattle them if they aren't installed tightly (slowly loosening the connection of the mounting to the surface it is mounted upon over decades) and if severe enough, high winds can blow them off a roof like shingles. In places where hail happens with some frequency, it isn't uncommon to have to replace a roof due to hail damage every 10-25 years, which is considerably less than the expected useful life of the cells. Unless someone is covering the cells with shutters or some other kind of cover in windy, stormy weather, it is likely that most will be seriously damaged over the course of a century or more. A third concern is that photo-voltaic cell installers don't always pay a lot of attention to the materials in the frame and mounting. Iron and copper corrode, and over time, even coatings designed to prevent that from happening will wear off. Another kind of issue would be bird poop, leaves and dust, but these would merely temporarily degrade performance until the panels are cleaned. [Answer] If panels are kept reasonably well (and are not stolen, of course) yo can expect a mean degradation < 1%/year for reasonably good quality panels (the whole story is [here](https://sf-asset-manager.s3.amazonaws.com/95679/29/19855.pdf)). This means you may expect to get about 1/3 power out of the panel after 100 years. This figure already includes small damage due to "normal" wear and tear (temperature stress, cleaning, ...) but does *not* include major events (e.g.: a tree falling over the panel or it being stolen). Note this figure is constant for a certain number of years (dependent on quality, but surely >= 50y), then will start to increase due to other factors collectively labeled "corrosion of cell and interconnect" that can be disregarded for a certain period, but later become prevalent and depend heavily on maintenance (especially waterproofing as sealants fail after a number of years of sunshine exposure). [Answer] Solar cells works roughly on this way: [![enter image description here](https://i.stack.imgur.com/FtT9W.jpg)](https://i.stack.imgur.com/FtT9W.jpg) The here important part is, that the photons of the Sun push the electrons out of the base plate. These electrons can find their way back only after they made some work for us. To make this possible, that base plate should pass very strict constraints (in its crystall structure and materials what it has). Furthermore, it depends also the energy of photons: 1. Photons with too small energy (infra-red) are incapable to do anything, they are reflected back or they heat the solar cell. 2. Photons with the needed energy do as we want from them. 3. Photons with *too much energy* (they are mainly ultra-violet) can *damage* the base plate: they disorganize the crystall structure and the plate coating. Obviously the solar cells on the Earth are tuned that the most solar photons fall into (2). But not all of them. To prevent the problem of (3), typically the antireflection coating has also a filtering function, to filter out the possible most harmful photons. But this is not perfect. The result is that the effectivity of the solar cells still decreases with time, and slowly they will become unusable. How long they last, it depends mainly on manufacturiing details, but none of them would last forever. As the large-scale solar cell manufacturing is a young industry, there is yet not enough practical results. Different estimations around the net say some decade. [Here](http://energyinformative.org/lifespan-solar-panels/) is a detailed list of the typical degradation of the solar panels. This list is for the currently most common application, their real timeline likely significantly depends on the anti-UV coating, too. It could be tuned, but it would require to make the antireflection/ultraviolet protection layer much more costier *now*. It is un-economical for the sake, to make them lasting longer *decades later*. [Answer] Solar panels are more durable than they are being given credit for here. Regarding fragility and susceptibility to physical damage consider the potential damage from hail. All panels are tested to survive at least 50 MPH hits from hail, most are up to higher standards, and a few manufacturers even build and test to 250 MPH (I'll leave that to you look up as I don't want to promote any brands). For reference, one inch hail stones (considered severe and only likely to [hit 0.5% of panels](http://www.isws.illinois.edu/pubdoc/CR/ISWSCR2009-12.pdf "hit 0.5% of panels") in a 20 year time frame) [travel at 45 MPH](https://hypertextbook.com/facts/2005/AliciaKosiba.shtml "travel at 45 MPH") (Another source, [NASA JPL from 1978](https://www2.jpl.nasa.gov/adv_tech/photovol/ppr_75-80/Hail%20Risk%20Model%20-%20IES1978.pdf)). As far as nuts falling from a tree go, they have significantly less impact than hail. Also, I'd recommend against putting your solar panels in shade but I'm no expert. If you want to see an example of a severe storm having little impact on a PV system, [here you go](https://energy.gov/eere/articles/hail-no-national-labs-solar-panels-survive-severe-storm). Mechanical stress is unlikely to be a factor in your scenario. Degradation is really the only significant worry. Modern solar panels are better than older panels, though. They degrade at approximately [0.5% per year](http://ieeexplore.ieee.org/document/6930713/?reload=true&arnumber=6930713) linearly. Older panels averaged 1% per year over 20 years and often followed a bell curve (so they'd get worse faster). After a hundred years of use the median panel will still give you 50%. I imagine that's not going to be your biggest worry in a post-apocalyptic world. All this is assuming you are finding panels that have been used for a hundred years. If you're talking about panels that have been in storage or have only a few years of use things are better. Corrosion comes from the environmental conditions, namely humidity, wind, and heat. A new or shielded panel will have very little of this. Degradation comes from the heat around the panels as solar panels get very hot while under the sun and generating electricity. Again, this won't have taken much of a toll on new panels or panels in storage. [Answer] As others have pointed out, modern silicon solar panels degrade about 1% per year assuming no physical damage. So the odds of them producing a significant amount of power after 100 years of actual weathering aren't that good (unless maybe they got buried in dry sand or something and miraculously didn't get broken as it shifted.) There are other types of solar panel, like black copper oxide, that don't suffer nearly as much degradation from use. But they're much more expensive and much less efficient, so while some of them could last 100 years, you'd be unlikely to find any except in the ruined homes of crazy, old tinkerers. And they'd still be big, heavy, and horribly inefficient. ]
[Question] [ * Consider the zombies to be human-like, with characteristic zombie gait, only differing in that they don't need to eat, they eat out of taste for human flesh, not out of a need for nutrition. Do not consider normal metabolism. They can very well run continuously, accumulating lactic acid without pain. There's no thermodynamic limits for them, besides that they can do whatever a normal human can do physically. They feel no pain and have the IQ between a cockroach and a anemone. In other words they are purely reactive. They seem to not have immune systems, so they rot under anything that consumes flesh. They only stop moving when they are out of muscle tissue. The difference in speed is due to activity in cerebellum, its a matter of remembering how to run. The smart variety still remember how to do trivial tasks like opening doors. The dumb ones can only run towards a target. If they lack a leg they will be unable to stand up, walk or run. They have no tactics whatsoever. * Consider the Roman army well supplied and protecting a large walled city. No zombie casualties inside the city so far (the city is clean). The Roman army has to go outside and restart trade routes in order to resupply the city. Ignore countryside. The task at hand is simple. Protect the city and reopen trade routes. Consider standard equipment and tactics. The city is a large city but is not Rome itself. Given a standard occupation roman army from Caesar or Augustus time, and a horde of archetypal zombies, how would the roman army fare versus the zombies? What tactics should be used ? [Answer] The Romans could equip themselves with better arm and head armor and do quite well against the zombies. Since the zombies are unarmed and unarmored, the only major threat they pose to the Romans is the threat of infection due to biting. The Romans need to make sure the zombies are dead before they can get bitten. ![enter image description here](https://i.stack.imgur.com/VJAC0.jpg) A standard soldier, as seen above, has roughly the following equipment: * Throwable spear (pilum) * Short sword (gladius) * A large shield (scutum) * Armor over the body, neck and head This protects fairly well against most of what a zombie can do, and gives the soldiers a quick way to take out a zombie via slashes and stabs to the head. The one danger is that, while slashing, an arm could be bitten, since a standard Roman soldier has no arm or hand armor. With this armor, a Roman soldier is unlikely to sustain significant damage unless the zombies can overwhelm the Roman shield wall. Luckily, or zombies are incredibly predictable, and we can use this predictable nature to deal with them. We know that they will run continuously towards humans, without paying to much attention to where they are running. We also know that they don't run any faster than normal people. Our soldiers should start by preparing an area for slowing down an approaching zombie horde. Trenches, caltrops, and small walls of pointed sticks can be erected as a barrier, with a path wide enough for a horse to ride through left clear down the middle. Horse-jumpable obstacles are fine on this path. Once the fortifications are done, the Romans should send mounted soldiers out to go find some zombies. We know that the zombies will follow the horses, so the horses can lead them back to our fortification. Our horsemen need only to lead the packs back through the fortified area towards our entrenched infantrymen. As the zombies slowly mangle their way through the fortifications, with our legionaries hacking them apart on the far side. The fortification need not stop our zombies, only slow them down sufficiently as to not get our shield wall overrun. Pila thrown by the rearward ranks of the army will further slow the zombies down as they approach. Since legionaries have bare legs as well, they'll want to retreat in waves to keep some space between themselves and fallen zombies. After each battle, hack apart and then burn all of the dead from both sides. [Answer] The key issue for the Romans (assuming the usual zombie tropes apply) is that most Roman weaponry isn't designed for destroying zombie brains. The initial wave of zombies will be met with a shower of pilla. To the horror of the Romans, the spears will stick out of the zombies, but they won't be stopped for the most part (a few will be pined to the earth, but obviously still capable of motion). As they close in, the Romans will move to a close formation and draw their short swords. In contact, the Romans have been trained to make short stabs into the torso of the enemy, which zombies will simply ignore unless major muscle groups are severed. Once again, following standard zombie tropes, the Roman shield wall will be overwhelmed and pushed over. Many Romans will be infected (although because of the armour, a lot of Romans will not be eaten). Now follow up forces will have a problem, not only will their usual weapons and tactics not be effective against zombies, but some (a lot?) of the oncoming horde will be armoured, and thus even more resistant to Roman arms. The Romans have a few things in their favour. Because they were great engineers, they have the ability to build defences against the oncoming zombies with enough time. The zombies will find large ditches, walls and abiti of fallen trees blocking their advance, and they will not have the awareness or ability to overcome obstacles except by filling ditches with their bodies. The Romans can also pull out siege engines (once again with sufficient time and warning). Zombies might not react to a sword thrust or pilla impaling them, but being crushed by large rocks falling from the sky will certainly destroy their brains. The Romans also have access to fire, once again with enough time and warning they can fill pots with oil and send fire against the zombie horde, burning a lot of them and cooking the infected brains. So if the Romans have an idea of what they are up against and sufficient time, a legion could throw up a wall and ditch around their position, and use siege engines and fire to destroy the zombies that are trying to eat them. A relieving force will need to have sufficient siege engines and ammunition to clear the fortified position of any zombies left after the garrison ran out of rocks and oil, before marching up and freeing the trapped garrison. [Answer] The Romans were good at adapting strategy and equipment. During the Dacian wars, they added arm protection and shin guards to the equipment, and it's no reason to believe they would not do the same after the first encounter with the zombie horde (if the fort did not fall to the infection...). Next would probably be switching out the gladius for a weapon more suited to decapitating/skull crushing. Dolabras (mattock axes) would be available right away, but my guess is they would eventually settle on falcatas or something similar. The shield would be very useful, but the pila next to useless. The Romans would probably approach this an an engineering problem. They would need a series of small zombie-proof forts along a stretch of road to the next trade settlement, in the style of Hadrians wall. A couple of big ballistae with Greek fire would probably be able to secure a safe zone for constructing a fort. Once a new field fort was built, the ballistae could be moved forward, allowing for a new one. The strings of forts would eventually be linked by a double palisade-protected road, eventually upgraded to a raised road (a viafer) similar to an aquaduct or the Wall of China. Not only would it allow for safe traffic, it would also be a suitable structure to depose criminals, deserters and the occasional religious dissident from. ]
[Question] [ I have toyed with the idea with a certain creature in my head for quite some time, and with the [creature design challenge](https://worldbuilding.meta.stackexchange.com/q/1862/2113), I thought this would be a great time to ask about it here. The basics of the creature is fairly simple. It is a ferocious [manticore](http://en.wikipedia.org/wiki/Manticore)-like beast, but the end of its extremely long tail is fused to the tail-end spine of a human. This human is an exact replica of a real human, with working internal organs, brain and the like, however, the human is part of the manticore as well. The creature likes to hunt noble souls, by taking its human tail as an angler-fish like bait, making it run around and screaming for help, then while the heroes are distracted trying to help and calm down the human tail bait. Now herein lies the problem. How can the human tail bait thing be preferably physically connected to the manticore in a reasonably non-vulnerable way, while also allowing the manticore and the human tail bait to have a large distance between them, enough for the 5m tall manticore to lay in wait? Notes: * The creature is created by some powerful wizard, from dust and the corpse of a human, with loads of magic. * The human tail bait thing will appear to also be in distress and claim that it is bound to the manticore chimera. This is a ruse to make the heroes drop their guard in order to try to save the human tail bait thing. The human tail bait has no self, it is the manticore chimera. * As noted above, it is preferable for there to be a physical organ connection, but any other means may work as well. * The creature is fully intelligent, and can speak from both its manticore mouth as well as its human's mouth. [Answer] **Disguise the bait as a fellow noble soul.** Your intrepid heroes are travelling along when they spot something ahead. On closer investigation they find that it's an (apparently dead) manticore, with a knight pinned underneath who's been stung by the tail - in fact, it's still impaling his body. On closer investigation the knight is stirring weakly and calls for help - he claims that he managed to finish the creature, but he's weakening from the poison and is unable to free himself. Won't the heroes help him move the manticore and give him first aid? Of course, being noble souls, your heroes will immediately rush forward to help this knight out... [Answer] The first problem you'll have to overcome is that the 'bait' has a tail; of course, we know it's the tail of the manticore, but to the 'heroes', it looks like some guy with a giant tail sticking out of his back, which could probably be followed all the way back to the real problem. To solve this, you'll need some form of cover, something that the bait can hide its tail behind. I'd suggest it shouldn't run around, but instead should stand mostly still, or even lie on the ground. But you still need it to attract the heroes. So let's say there's a ruin of a cottage (manticores are excellent at creating ruined cottages, so long as there are spare cottages nearby). The manticore slides in under the rubble and thatch of the roof, and wriggles its tail until the head and upper body of the bait are barely visible. When the heroes walk past, they hear the pained cries of a man, and quickly find him 'pinned' under a large stone. Perhaps he tells them a story of a fearsome manticore attack that killed his family. Being nice people, they of course run over to help the man, and now are near enough to become easy prey for the manticore. Another option could be the manticore lying in wait on a cliff face, with the bait appearing to be a man hanging onto the cliff edge for dear life. Or the manticore could hide behind a large boulder while the bait peeks out, maybe pretending to be hurt and thus using the boulder for support. In all of these situations, the manticore can hide itself relatively easily and still be very close to its bait, thus not requiring too long or delicate of a tail. I would even go so far as to say the bait doesn't even need legs (or even human organs), especially if the manticore is able to clothe it in a long robe. **EDIT:** As per your 3rd note and the fact that some manticores supposedly have scorpion-like tails, I came up with an alternate idea, of a **mind-altering poison**. The manticore finds a lonely traveler, and instead of eating him outright, it poisons him with a swift strike from its tail and leaves him bleeding on the road. When the traveler awakens, suddenly he can't remember where he was going, and his vision has become blurred, but he has a vague recollection of a traveling companion, a close friend or family member, who is now nowhere to be found. The man panics and stumbles around, searching for this imaginary person. When the heroes come by, the man pleads with them to go back with him to the spot where he lost his friend, and help him search. They can see that he's been hurt, and of course want to help, so they follow him right back to where the manticore is hiding. With this method, there is no physical connection between the manticore and the bait, but the bait can be easily replaced and the manticore still gets a viable weapon on its tail. It could even still have the man-shaped tail, to masquerade as the imaginary companion, but it would no longer have to be as lifelike, as the only one it has to fool has been drugged/poisoned. [Answer] Since this is a magical creature, the fake human doesn't even need to really exist at all. Simply give the Manticore a special illusion-projecting tail that allows it to project any type of illusion they like - optionally with audio illusions, but equally valid to make the Manticore an expert at throwing its own voice. This would mean that the 'human' isn't actually attached to the Manticore though, so it would spoil the monster a little bit if that is absolutely essential. Or it may be a corpse that is made to look alive BY illusions, either focused from the manticore's tail, eyes, or some other part of the manticore (which would also allow it to hide its true body with the same illusion). From there, whatever form you feel would be most 'alluring' to the noble types can be used, since as an illusion, it can take any form it likes. [Answer] The manticore could be an arboreal creature where the tail mimics someone tied to a tree. The tail would be long and resemble a thick liana, or an exposed root when in the ground. The tail would connect to the bait's feet. The manticore would hide on top of the tree, and have things resembling branches and leaves to help blend into the tree-tops [Answer] The manticore can lay waiting in ruins or caves with lots of broken structures or loose rocks. Instead of having a running lure, the lure could be placed under a rock or debris in such a way that it looks like the victim of an accident. A rock could then cover the tail. Since the manticore is five meters long, it should be strong enough to lift the rock at the right moment. Might even use the rock to beat the heroes down. Or the manticore itself might disguise as the rock or debris. --- Alternatively, the manticore might be aquatic. The lure would pass by a drowning person in a mangrove or some other kind of place where you could chance upon someone after turning a corner. The heroes would try to help the drowning person, and the manticore would drag them down. ]
[Question] [ **TL;DR: I want a society which behaves as a hive. Is it plausible and how to achieve this?** *The setup:* Different planet in our universe. In other words: Normal, physical rules apply, there is no magic involved. I would like to have plausible explanation for everything. *Bonus:* Because This is around *creature*building and not *world*building, I am leaving out the world setup. But, obviously, I would like my creature to meet with humans, so I would like to end up with a planet, which can also support trained humans to survive (= human who went through nowadays NASA astronaut training). And as I am typing this question, one becomes obvious: The planet has to have at least one moon. *The creature:* As stated in the bold text above, I would like to end up with a creature which: * Shoots for the moon (and at least has the technological level to go there) * Has hive state of mind (possibly evolved from ants or bees) * Is large enough to be recognized by human as someone "who runs the show" (ant of size 0,5 meters to start with?) * Looks like the insects here on Earth. Does not need to look exactly like an insect, but on the first look at it you would "categorize" it into insects. *The question(s) (again):* * Is such a creature actually plausible? Could evolution process end up in "intelligent insect"? * What traits does such a planet need to have in order to maximize plausibility of such evolution? And ultimately: * Would that planet be able to support astronaut's life if (s)he takes off their helmet? [Answer] Starting from simplest to most complicated, lets tackle the size issue first. ## Large insects physiology Insects do not breathe with lungs the way we do. They have many spiracles distributed over their body that open into many tracheae which allow oxygen into their body. They can't use expanding lungs the way we do because their exoskeleton cannot deal with that much flex. [Studies](http://phys.org/news79804314.html) have shown that the ability for large insects to evolve is highly limited by their ability to get oxygen to their leg muscles. Increase oxygen, such as in our Paelozoic era, and you increase their ability to get large. **You want a Paeleozoic era level of oxyegen in the atmosphere of your planet.** **Low gravity would also help large insects be realizable.** While it appears large insects *can* evolve in Earth like gravities, they are bound by the [Square-cube law](http://en.wikipedia.org/wiki/Square-cube_law), and it seems more likely that exoskeletons will remain a valid solution as they get larger. **An unfriendly planet will increase the viability of exoskeletons.** The big advantage of exoskeletons is that a strong strike from the world around you does no damage as long as it wasn't sufficient to crack your shell. Endoskeletons will be more desirable in situations where it is valid to take a little damage from a strike, and then heal it afterwards. If the environment is hostile, with many potentially killing blows around every corner, shielding will be more useful than repair. ## Culture of a Hive Insect Population The defining characteristic of the hive mind is an unusually strong correlation between the actions of individuals, apparently centered around the mind (historically depicted as the "queen" of the hive). In order to do this, there must be communication -- constant communication. Much of this communication is built at the genetic level (especially given the short lifespan of bees, giving few opportunities for learning). This is where your question gets interesting. **Going to the moon is a HUGE communications gap, which limits this communication. This is going to drastically decrease the culture's desire to travel to the moon.** It's just not the nature of a hive mind's mentality. Two directions which could help are RF technology and genetics. Consider a world colonized by one or more of these hives (you did not specify if the entire species was a hive, or if there were multiple competing hives, like ants). They would eventually reach a balance, and live in the best harmony the planet can afford. **The discovery of RF communication could dramatically increase the rate of their communication, and allow it to occur through the vacuum of space.** This would, in a flash provide a new surface to colonize and trigger a space race. However, a hive mind would use communication as simple as ours, so it wouldn't be as simple as a phone conversation. Hive minds require coherency, and the easiest way to do this is analog communication such as sounds or dances (digital brings up all sorts of timing woes that, in my opinion, prevent a hive from functioning adequately). Just because they had a new technology like RF wouldn't cause them to immediately shoot for the moon. They would need to adapt the technology to their communications. Thinking about how such a race would become so powerful, their individuals would have to be well programmed. Such a race would probably need a way to genetically wire their workers to listen to the right commands and act accordingly. **They would probably conquer genetics and biology long before RF.** Accordingly, they could design workers that would be custom engineered to respond to RF communication just like their primitive songs and dances. I would also expect them to split the difference between biology and technology: **I would expect the technology to be physically adapted to be more similar to their primitive songs and dances.** How much of this balance is genetic, and how much its technological is pretty much up to you. ## Choices I would consider looking at more complicated hive mind structures than the simple queen+workers pattern, because there's a lot of room for creativity there. If there is a multi-level hierarchy, the queen might install a lieutenant on the moon, equipped with powerful RF communications. Alternatively, a simple queen+workers hierarchy might simply be looking for a backup plan in case something went wrong on their planet. Being able to evacuate the queen to a moon already colonized by workers could be a strong strategic move. [Answer] An alien that *looks* like an insect - i.e. has an exoskeleton - is quite plausible. We do not get such creatures of the size you desire here on earth simply because insects have an open circulatory system and a largely diffusion-based respiratory system, however, an exoskeletal alien of larger size would need - and there is no reason why it could not have - a closed circulatory system and a more efficient respiratory system. The Square-Cube law limits the size of any creature, but aside from relatively thick-seeming limbs, an insectoid alien of approximately human size is still quite plausible. It would be plausible even up to elephant sized in a 1g environment. If their home world's gravity is lower, they could be even larger or more spindly. If you look at [this](https://worldbuilding.stackexchange.com/a/510/75) answer I gave about creatures with a hive mind, you'll see that biological microwave communication would be the most efficient means of communication for such a species. The thing with microwave communication is that they may be able to communicate at interplanetary ranges if they made use of signal boosters, and they may even be able to communicate at lunar ranges without such artificial enhancements. In order for a species with a hive mind such as the one I proposed in the answer I mentioned above to evolve, high levels of free metals in the environment would be desirable. This may lead to an environment somewhat toxic to humans due to the presence of heavy metals. In addition, another extant or extinct sentient species could provide the evolutionary stimulus required for a hive mind to evolve, as could a highly unpredictable environment full of predatory species. Of course, this would likely leave our hive very suspicious of other species, especially if they are sentient. A species with a hive mind, in my opinion, is highly likely to attempt exploration of space. Population control may be alien to such a species except in the form of inter-species or inter-hive warfare, and thus *lebensraum* may be of some importance, and the species intelligent enough to consider the possibility of finding some off-world. As to the human-survivability of these beings' home world, I would say that there is no reason why not. An oxygen atmosphere is plausible, though the exact level of oxygen may vary from our own. If species on this world rely on metals, there *may* be heavy-metal dust that would be toxic in the mid to long term, but a simple dust mask would provide sufficient protection for humans in the short term. Gravity may be higher or lower than on earth, but if the atmosphere is human-breathable and roughly earth temperature, surface gravity is unlikely to be more than around 1.3g as higher gravity would allow accumulation of helium or even hydrogen in the atmosphere. [Answer] Cooking will make them intellingent. Any animal on earth can replicate anything a human can do,except cooking, this might be the one thing that enabled us to become intellingent, and we are the only species on the planet to have this skill. Humans have schools: Wolves too! Humans have tool use and crafting : So do most social animals, even birds and ants do. Humans have emotions : just like any social animal Humans can hunt : And so does any other predator yet they are not so smart.. But only humans can cook. [Answer] (first post.) most more intelligent animals have slower reproductive times, (due to complex brains taking longer to develop) and smaller litter sizes. so, in order for insect-like creatures to become intelligent, I would assume that "queens" would breed slower. having hundreds of dumb cannon fodder is no problem if you make 10000 more in the time it takes for 100 to die. however, if you breed slower, evolution probably would push towards intelligence. now, let's say you have gotten intelligent. I know beehives on earth have hundreds of members all "talking" at once, but communicating with pheromones sharing complex ideas in a room with thousands of other individuals would be a hassle. [Answer] Being aliens, these creatures would indeed be more "*insect-**like***" than "***actual*** insects", (presumably with lungs, a cardiovascular system, etc) but that could still leave them with "growing pains" from the exoskeletons. Thing is, the species here on Earth that use exoskeletons (like crabs/lobsters/etc), tend to have to shed them regularly as they grow, leaving them vulnerable until the new one has been properly grown. Which would be why insects have this stage where they grow their one and only skeleton, which they then keep using until they die. Hence the three stages (egg, larva, pupa) before going into full adulthood. Our alien friends could be expected to have a somewhat different road to adulthood. Like the queen giving birth to live larvae to bypass the egg stage. Being large enough to be intelligent (even sentient), they may also have a way to school their young in the new ways of a world that changes too fast for (natural) evolution to keep pace. That way the new adults would have more than just instincts telling them what to do (and how to do it). --- However, one question that people seem to miss, is ***what causes such a species to develop tools in the first place***? (Even if we don't necessarily witness this particular stage, it'll still be useful to consider when building the species) I'm obviously thinking **artificial** tools, like knives, hammers, etc. It's one thing to have natural appendages, but picking up a tool for the very first time ever, takes some imagination. Especially when you then also start to make them yourself. And of course, having appendages (like hands) capable of actually *handling* the tools, would not go amiss. [Answer] 1- Technologically capable of getting to the moon is pretty easy if they start developing technology in the first place - figure out how they began using mechanics and chemistry, and you figure out how they developed up from primitive to higher levels. Looking at ants, chemistry would seem an easy field for intelligent species to investigate due to their use of pheromones and therefore highly sensitive chemical receptors. How would tool use begin in the first place? They have to be capable of manipulating primitive tools (found sticks and rocks) in a way which is superior to their built-in appendages. I could see them developing pottery and then glass for storage and mixing, add in metals and you get batteries and electrical investigations, but this is still presuming they would have a curiosity and investigative drive I'm not sure would exist in a 'hive mind'. 2- a hive mind is tricky to describe. it is not really a single intelligence but a mass of individuals working in a cooperative way. We may look at an ant colony or beehive and think they all are working with a single mind, but that is far from true. One means of producing what may seem like a 'hive mind' would be to have very low levels of individuality or variations in personality with high levels of communication. This is very easy to explain by having little adolescent development of mind. If each generation in a nest is be genetically identical, and they don't have much of a childhood development (brain is pretty well grown into adulthood as-is), they could be so similar they may not even have a well developed sense of individual self (just each generation of each nest as an 'individual'). 3- recognizable as dominant, technologically advanced species. this has nothing to do with size, but would entirely rely upon displaying technological development - probably by demonstrating tool use (could use a radio to call back home to alert people of a human showing up). Maybe wearing a toolbelt or something. 4- If this is to be immediately reminiscent of an insect, the size issue is going to be a problem. The oxygen levels would need to be extremely high and/or some non-insect breathing is done. This isn't too hard, as they can be internally very different than an Earth insect despite outside appearance - a circulatory system with blood pumped through wings could provide all the circulation and heat regulation they need (faster flapping gives better gas exchange and shedding of excess heat). The shape will fall victim to the square-cube issue of requiring enormous legs to support an incredibly heavy exoskeleton (endoskeletons have the biggest advantage here). This could be slightly ameliorated by them being at least partially aquatic - they could have evolved from small flying insects, becoming terrestrial as they got bigger, and then amphibious as they got too big to be comfortable on land (think insect hippos - land-dwelling but happier in water). Perhaps as they evolved into larger sizes, their exoskeleton got thinner to save on weight. A good impetus for technological development might be tight leather clothing/harnesses to help hold their bodies together out of the water (less strain on their shell), maybe metal plate armor to protect their thin fragile abdomen/thorax chitin against attack. Their legs would still be very burly relative to Earth insect proportions. More legs than just 6 would help distribute the weight a bit (dodecapede?), but still nowhere near as spindly as would be visually similar to terrestrial insects. [Answer] For this question we first need to understand three topics. - biology (insects, invertebrates and hive mind animals) - hive minds - the technology tiers Biologically speaking it is possible for a insect like species to develop but it would need to develop in a certain way. Evolution made us bipeds and two armed and two eyed for a reason, it’s the best way for a conscious species to develop. Hands for the usage of tools, two legs because it’s the least amount of limbs you need for walking and two arms because it’s the least amount of them you need, as well as eyes. It could also be possible for said beings to have more than two eyes but they would have to follow the structure of wasps or other certain insects (three simple eyes, like ours, and two complex eyes, like those in flies) but they would certainly need two simple eyes, like those in humans, because of the ability to sense light, colour and Depth. But it could also have many pupils in one eye, such as the mantis shrimp, which has two eyes but three pupils in each, as well as the ability to sense more colours than that of visible light (ultraviolet light and polarised light). It could also have two arms but their evolution will require a totally invertebrate being. A vertebrate being can only have two arms because of the structural complexity. It would also need a complex closed circulatory system and a complex breathing system to develop a human like size and also a greater capacity for evolution towards intelligence. The thing that would make it insect like would be the exoskeleton. Many frown down upon this idea but that’s because they don’t realise the ways you could circumvent it’s problems. An insect with fingers (to manipulate and create tools) could pretty easily take its exoskeleton off when molting. It could also when molting, secrete an enzyme that begins breaking down the old exoskeleton while creating a new one under it. Processes like these are found somewhat in the formation and shaping of bones. So now we have our finished alien. An anthropomorphic being with (most probably) two arms, bipedal, two eyes and a very complex exoskeleton (whose plaques should remind of the muscle system on vertebrates). It could have horns, a funny color, be aquatic, have regeneration, or even be able of secreting webs or acid. Also it probably would not be able of flight, so they would probably remind you of a crazy hybrid between a human, an ant and a crustacean. That’s the end of the biological topic. For hive minds you have to understand that these insects don’t share brain waves, they just communicate constantly through the use of hormones. Your aliens could have that but they probably couldn’t go to the moon because of the complexity of the actions needed for that without hormonal instructions. And because they are sentient they must also be able to communicate through various means (just like how humans can communicate through facial expressions and also speech). On the other side, hive minds require the minds of the workers to be “empty”, awaiting the next command, while the queen would send out all orders. If you want you species to be entirely sentient then there would be no queens of the hive mind in a sense. The species would all have intelligence and “freedom of thought” but the rulers would still be queens since they are the ones that can create more brood. They would still be separated into classes and functions such as termites : - infants (nymphs) - workers (builders, scavengers, groomers and caretakers) - soldiers - reproductive substitutes - king and queen You could make it that the nobility is the reproductives and they are constantly creating more brood, while the soldiers are always protecting and destroying threats, while workers continue with their functions, also being allowed to choose their function by controlling what morph they shall take (basically choosing what work they will perform, by psychosomatic reactions). An idea would be that they develop many technologies before venturing to space until they develop neural chips that they implant on their brains to connect each other on a constant communication array (which would also include many awesome technologies). And that’s when they venture into other worlds (also developing the suits and technology to do so). They would probably not develop AI since they reproduce constantly and they have a vast array of loyal servants but they could do it for communication purposes I suppose. That’s the hive mind point taken care off. For the technological tiers you’d have to understand the functions to follow in every society : - digging - building - farming - ranching - cooking - decorating - researching - suit wearing - supplying - operating - doctoring - tidying These functions must be carried out, and every species must develop in the seven tiers of technological progress : - pre-industrial age : before the engine - Industrial Age : the age of the engine - atomic age : knowledge of the universe and the creation of fission and fusion. - space age : satellites into space and space exploration through probes. - space faring age : the development of the warp drive. - interstellar age : the creation of a galactic civilisation. - world builder age : the total understanding of the universe workings, and the end of progress. You can see that the colonisation of their moon would be a type four civilisation trait. They would need to have conquered their world totally and then try to terraform their moon by colonising it and then transporting materials to it to make it like their planet (they should need space suits accommodated to their needs, the neural chips, complex space ships that would find, collect and manipulate materials). I hope this was of help. ]
[Question] [ The premise is a low-tech world such as Earth prior to 1600 CE but with a fixed number of magical/technological teleportation portal pairs scattered across the world. Each portal only takes travelers to its paired portal. The workings of the teleportation are no longer known so the portals just stand there and do their thing. The question is how do I arrange for the world around the portals to *not* globalize? My current thought is for them to be controlled and their use regulated by what passes for local government but that is prone to change as power struggles cause them to change hands over the decades/centuries. So I am looking for something more structural to make them usable but without causing cultural/economic globalization. **Edits:** My intention was that the portals would be seeded during world building and then be unmovable by means that the various civilizations have available. So they are like rivers, useful but you take them where they are. The sense in which I meant globalization is a process where cultural and material exchange is below a threshold where it becomes more reasonable to talk of a single large civilization/economy rather than several smaller civilizations/economies with some interactions. There is no hard and fast line between these extremes but I am looking for something that helps the civilizations remain distinct rather than pushes them to merge. [Answer] You have actually partially solved this yourself. The key to globalization is a network. A link between two points is not enough by itself, you need those points to connect on to other points. Towns where there are these paired portals would have commerce and trade between themselves and knowledge would travel faster but that would not be enough to globalize by itself. Particularly if the portals were too slow or too small to reasonably permit an army to pass through. They would be useful for messengers and you would end up with an interesting "distance map" when you look at travel from one point of the world to another but they would not be enough by themselves to reshape the world. One thing you might well find though is that a town that happened to have multiple endpoints for the pairs inside it would end up growing and becoming a central hub as a result. Many capital cities might well have that benefit and access to appropriate portals would be a major strategic advantage, as important as rivers and defensible positions are. [Answer] Make the transaction cost high. Modern globalization occurred because transaction costs plummeted: payment, travel, communication, shipping, etc. Maybe the portals make you sick, sap your health, 10% chance of death, take a day/week to recharge, requires gold to operate, etc.? [Answer] If you mean real Globalization like today where most people have some idea of the rest of the world and accept Africa and China and trade goods across the globe, then the number of teleportation devices would make the real difference. If you only have a handful of these teleport locations scattered around the globe groups who know about one pair probably would not know that any others exist. People don't tend to travel far without decent transportation. So assuming that the people who have one don't fear it as a god or devil technology and actually use it then it would likely be treated like going to market or traveling to the 'big city'. Without the understanding of the globe, people might think that they are traveling to a strange and different "planet" not just to a different part of earth. So connecting the Navajo with the Han won't make the French know about South Africa. You'll really only have blending where the 2 cultures meet. And the Chinese for a long time didn't 'blend'. Also if one end of each pair are clustered into one location, it would tend toward Globalization around those connected cultures around a central trading city. However, if there are hundreds or thousands of these portals around the globe, then having a few close enough together for knowledge of them and what they can do will have people in power looking for them and wanting to control more of them, and knowledge would spread between them. Even more, if a pair happens to be close enough together that someone might have physically traveled between them and recognize both ends and what it means, things would start to get really interesting. And real Globalization will be almost impossible to avoid. Just consider each portal as a trade route and go from there, looking at cities on trade route hubs. [Answer] So you have a couple options that I can think of. 1. Make them geographically remote, top of a mountain, middle of a swamp, you get the idea. Limiting their use would limit the impact of culture transfer significantly and no one wants to live in the middle of a swamp so if you place them away from "civilization" in places that people have trouble getting to, that should solve that. 2. Their use requires something beyond the average person: Maybe you have to be a mage to activate them, maybe you need a certain relic (there could be many of said relic) a passport so to speak. 3. Limited number of portal pairs. On an earth sized planet a dozen pairs connecting certain parts of the globe wouldn't make a huge difference in globalizing things just because of the scale of the planet, this is even more true if you combine it with #1 or #2. [Answer] Commander Sanders of the Colonial Engineers 3rd Brigade, Set-Prep Ship Isis reporting. We arrived planetside eight standard years ahead of the multi-gen colony ship, with only one third of our original equipment. Our sister ships, the Farrigut and the Ontarsis, were captured by slaver pirates (details reported separately). Of the settlement development equipment lost, the most notable absence are the majority of the TeleGates. We are left with only sixteen mated pairs and no multiplexing hubs. From the planetary accessment scout's report, we determined that ten of those pairs will be needed just to link the initial landing site with needed resources including farmlands, mineral deposits and the fishable coastlines on three temporate point of the main continent. Naturally storm protected bays have been chosen for each of these fishery gates. In keeping with standard practices, one of the gates has been affixed well above the permafrost line of the tallest mountain, ensuring access to fresh water at landing. That leaves only six pairs for trans-continental access. Since this planet has three major continents and two subcontinents, and considering that all of the major continents are bisected by nearly unpassable mountain ranges, even the most dispersed distrubution of these six pairs will leave more than 40% of the viable landmass and all of the island chains inaccesssable through civilized methods. Also note that with the telegates spread so thin, there is no redundancy. These things are built tough but if even one of the vital main continent links break down, the initial landing zone will become uninhabitable, lacking access to either resources, water or food. Since the landing zone is the only point where multiple gates are within walking distance of each other, if it fails, then this entire pitiful network will also. This planet is one gate failure away from "going primitive". God help those poor colonists if that happens. -- end of narrative -- My point is that the worldbuilders who installed the teleportation gates would not have prioritized globalization. The planet was empty when they arrived so there was nothing to globalize. Instead, they would focus on making the initial colony viable. If there were any resources available after that, they might try to clear the path for future expansion. [Answer] If you mean to prevent idea exchange, it's impossible even without teleportation. The ideas flow even with the weakest means of communication. If you want to prevent globalization in sense of massive traffic, the best thing to do is to limit the mechanics of the portals itself. Make them need to recharge each time someone teleports. Set the limit as you like, for example 1 person an hour, or 1 person a day. The portal will be unavailable as long as it is recharging, or it will be able to teleport smaller objects only, when not fully charged. It will enable single travellers to pass by, but will make it unable to be used to transport goods or enable mass traffic. [Answer] I would add one more answer. Make the two places at the different sides of the portal extremely different. That is, a portal between the frozen north and the burning desert, a portal between the humid jungle and the dark forests. Assuming people have adopted successfully to their local habitat, they may not want to travel to the other side at all. ]
[Question] [ My people live in a tidally locked planet with very strong winds from the night side to the day side. Normally these winds are **50-70 km/h (around 30-45 mph)** but they can easily reach 100-120 km/h (around 60-75 mph). I know that winds can be much faster in tidally locked planets, but it has to be an inhabitable planet. They have a **Bronze Age-like technology** with a strong, well-organized feudal power. The materials available are from animal origin (mostly **wool, leather and bone**). They live in houses dug in the sheltered side of hills and mountains, in a tundra ecosystem with little vegetation and few geological features. They do not have magic of any kind. **What kind of clothes would they wear to travel between locations**? Tight clothes so they can walk in the wind? Or baggy clothes that could take advantage of the wind and help them move, like ship sails? I would like to hear your answers, and please tell me if something is not clear. Thank you! [Answer] > > Normally these winds are 50-70 km/h (around 30-45 mph) but they can easily reach 100-120 km/h (around 60-75 mph). > > > I live in exactly such a place - you could have taken these numbers from my monthly weather report. It is also moderately cold. The wind is exciting the first few times, but it's honestly not such a big deal. A simple leather motorcycle jacket works very well to break the wind. Canvas "work" pants with tightly woven fibers also work well. Loose fiber cloth (so basically any generic "normal" clothing) is pretty bad - the wind cuts right through, and no amount of layering helps. In your example of a bronze age culture, their best bet would be leather. I'm not sure how tightly fabrics were woven historically - but I assume sailmaking would have developed the [technology for it](https://en.wikipedia.org/wiki/Cotton_duck). A single layer of that would be good enough in the conditions you describe - probably something that's almost the thickness of your average pair of jeans (so not super thin like a silk blouse). But you don't need to go overboard with super thick fabric. Among people in such a place, hat strings would almost certainly be very popular :). Also, after a quarter hour or more, the wind can really dry out hair, eyes, lips, nose and the rest of your face. It's not exactly a hazard (unless you're a beauty model) but it is an inconvenience. So various masks, gloves and visors would be popular accessories (also helps with snow and dust). Or perhaps they like to use creams, oils and waxes to protect their skin. One imagines that royalty might travel in covered palanquins, and lack of wind-dried skin might mark one as upper class, similar to lack of suntan in some cultures. Something I notice is that once you bundle up in some kind of tight overwear (leather or canvas), even if it's not very warm, you suddenly feel warmer because a significant wind chill factor has been eliminated. I'd say the wind can easily make it feel 5-15C colder. So when you put on the jacket it suddenly becomes much warmer. This is where zippered vents are really nice. I don't think historically such things were common, but perhaps in your case people would have all sorts of slits on their outerwear that are fastened by buttons or laces, and can be partially opened to cool off. [Answer] ## Clothing will be heavy duty 1. Slightly Loose: While you don't want your closes to be too loose since you want to minimize how much that wind will knock you around, some looseness will be good. Being a windy tundra, you will need a air gaps in your cloths to help insulate you from the cold. 2. Water tight: Those fast winds will be able whisk moisture away from your body cooling you down much faster than a normal tundra. Even if this is were not a particularly cold planet, hypothermia could be a real problem if you get caught wet out in those kinds of winds. But on a colder world, even more so. So clothes that are thick and don't breath too much could be advantageous. 3. Protection: Those winds are fast enough to send sand and debris flying. Your clothing will need to protect against the abrasion of a constant bombardment of sand, sticks, ice, etc. Getting knocked over and even dragged along the ground during a strong gust may be a very real concern as well. You would in most places see thick layers of furs like those used by the Inuits since staying warm will be your biggest goal, and all other goals would be secondarily achieved. However, no planet has just one climate. People living closer to the sub-stellar point will enjoy much more warmth than those living under less direct sunlight; so, this region may not be a tundra at all (just very windy). These people will likely still opt for full body clothing to protect themselves from the harsh winds, but thinner so they don't overheat. They will likely see going out for a walk in the open as a something that needs safety gear, like we do with bicycles and motorcycles, so I'd expect at least parts of their body to be protected by leather or rawhide protection. Bone or tusk helmets (like those used in the Mycenean Greek period) or maybe turbans may also be a common precaution against being stuck in the head or knocked down. Also, if they can find a way to protect their face and eyes, that would be expected too. [![enter image description here](https://i.stack.imgur.com/UQcuS.png)](https://i.stack.imgur.com/UQcuS.png) [![enter image description here](https://i.stack.imgur.com/BW93a.png)](https://i.stack.imgur.com/BW93a.png) [Answer] Let's start with the nature of the winds themselves. Yes, they'd be faster, and we can ignore that, but there are a few useful bits you could get fun ideas from. [They just figured out](https://www.sciencedaily.com/releases/2022/04/220420092119.htm) that Venus's winds are so strong that they actually abrade the planet to counteract tidal locking. This is why it has negative rotation and a day longer than its year. The motion of the planet, plowing headlong through the solar wind, created a slight bias that induced a single planet-wide hurricane where the winds circle the planet every four days. Ok, enough fun facts. Even if it doesn't make the planet rotate, it would create a reliable east-west bias of the winds, which would impact both architecture and transportation. I would guess that wind power was the target of most of their transportation needs. They would have figured out tacking shortly after they figured out cloth, so they'd have windward roads that went straight and widdershins roads that zig-zagged. Boogie boards would be their equivalent of walking sticks. Thus, their clothing would likely be adjustable so it could be tied back when traveling into the wind and let loose when they were making use of it for propulsion. The **looseness** of the clothing wouldn't be as important as the **stiffness**. You don't want clothing that flaps because that induces drag in random directions and will eventually damage the cloth. Also, fur would be abraded off of the outside over time, so you'd want the fur on the inside for most purposes. This makes it harder to be heavily insulated due to mobility issues. Smooth, stiff surfaces would dominate. Goggles would be non-optional, as would cloth over the mouth and nose. This is another area where they would see advanced innovation. Hats would be non-existent because you don't need them indoors, and you can't keep them on your head outdoors. So tight-fitting hoods, head-wraps, skull caps and helmets would be common. [Answer] The flora and fauna of such a world would evolve to adjust itself to the conditions you describe. If your People did not evolve in the same environment they would, as did we, harvest the local resources to allow themselves to live on this world. Else you may need to think of a reason why they are not naturally equipped to. I can imagine creatures like turtles with gripping feet that hug the terrain and shells that allow the wind to flow over their hard domes. Perhaps mammoth like animals with soft dense fur beneath but coarse thick fur on the outside. Plants, with heavy leaves and thick skin more rubber like but slick that let the wind channel over them, or large petals that grow on one side shielding the more delicate parts on the leeward side but still exposed to the sun. Insects that weave protective nests resembling silk. [Answer] # Baggy clothes bound tight. They wear baggy clothing that's wrapped tight around them and bound with cords. This has the benefit creating extra layers of insulation while reducing drag from the wind, and prevents the need for specially tailored, tight-fitting clothing for each different body—especially helpful for growing kids. ## Moving downwind. In the event they need to move downwind quickly, especially in emergencies, they release the cords and let their clothing catch the wind. For less experienced people, they slide along the ice and tundra—some on small bone sleds they carry for that purpose. More experienced people can stay upright, crossing large distances quickly in leaps and bounds. This is known as *running the wind*. [Answer] **No clothes.** Clothes slow them down. They need to move fast. No shoes either. They tie their hair back. From the movie "The Fast Runner" <https://www.slantmagazine.com/film/atanarjuat/> [![fast runner](https://i.stack.imgur.com/gHy4a.jpg)](https://i.stack.imgur.com/gHy4a.jpg) ]
[Question] [ My [polytheists with competing moon gods](https://worldbuilding.stackexchange.com/q/71/28) are going to have to contend with (what they think is) a new moon, and thus a new moon god, showing up. What are the most plausible ways for them to react to this? We have historical precedents for a new god *replacing* a local god or gods (religious conversion), and of going from polytheism to monotheism, but I don't know of any cases of a change like this within the context of an existing polytheistic religion. As far as I'm aware the ancient Greeks and Romans and the Norse didn't have new gods added to their pantheons over time, for example. (If I'm wrong about the lack of precedents, I trust that somebody will straighten me out in an answer. In particular, I know very little about eastern religions, so maybe there's something to be learned there.) Constraints: * They don't see this as *some other religion's* god, like happens when a religion seeks to displace local gods with a new religion. They have a pantheon of gods with a history/mythology already, and now it appears that those gods' number has increased. * Their pantheon consists of a sun god, the moon gods (one per moon), and an earth god. (There's no overall boss-god.) They don't have specialized gods for other purposes like war, fertility, lightning, and so on. * Their gods have not communicated with them about this (e.g. through prophecy). This doesn't mean that some people won't *think* they've received such communication, of course. * They're low-tech; they won't be launching probes or even building powerful telescopes to investigate the matter. My polytheists aren't necessarily human, but when trying to write accessible stories I find myself making aliens either relatable in human ways or very, very different. I'd like to stick to "relatable in human ways" here -- not human, but my reader should think their behavior broadly makes sense. [Answer] ***The lay people*** would naturally react how they would always react: * See if anything bad happens around the time, and use the change to explain it * Worry about new taxes/fees/sacrifices that the priests/shamans will demand, using the change as a convenient excuse (see below for possible options) * Worry that the change portends something bad, and look for hopeful stories proving them wrong. * When possible, try and use the new god's appearance to their secular benefit. "Father, I want to mate with that girl you disapproved of. Clearly, a new moon god appearing on the same day you forbid me means you have to change your decision". ***The priestly class*** would react by amending the mythos to include the new god. And - color me cynical - parlay this to their benefit. Plenty of natural explanations to use: **Path #1:** **mortal ascension to godhood**. Plenty of examples from our own history. Just taking Olympians, we have [Dionysus](https://en.wikipedia.org/wiki/Dionysus) being granted godhood in many versions (see Wiki discussion on he late addition to the mythos). Same thing happens in Heracles story. Dionysus is a very good example as he was clearly added on to earlier pantheon separately, as Wiki notes. **Path #2:** **Baby god arriving**. Again, drawing on Olympic tradition, we have [Hermes](https://en.wikipedia.org/wiki/Hermes). Well, the entire set is basically each other's kids :), but Hermes was added on later. This is probably the likeliest path - having children is a natural thing for human's gods. Your people would probably find details of the new moon (size, color, location) that are in-between of two existing ones and explain that it "inherited" from both parents. Or even more likely, all the moon gods are kids of sun god and Earth goddess (the latter seems to be typically female for obvious reasons). **Path #3:** **Errand done**. The god was missing due to being on an important errand, and finally got back. Or was completing training or right of passage and now it's done. Probably slip in an obscure legendary prophecy about it (that someone just made up). If I'm the priest making the prophecy, I get to ensure people pay me more goodies as a consequence. **Path #4:** **Keep up the good work worshipping!**. The god was previously unhappy and unwilling to show its face. As a result of heroic efforts of the priesthood (and now pay us more goodies to sustain that) we got the god happier... and if the goodies keep coming we will work to ensure the continued happiness. **Path #5:** **We have *always* been at war with Oceania**. If the religion has a more centralized and hierarchical priesthood (ala Egyptians), not a big deal to amend your official Party Line and add in a new god. You issue a new set of rules, everyone falls in line and worships under new rules. It may be good practice to smooth things over using one of the approaches listed above, but not entirely necessary. --- Another likely angle: if your moon gods are themselves specialized (the question seems to reject that option?), a new god would be a patron god of *something*. And if that something happened to be a recently powerful demographics that didn't have a patron god, they would clearly make it worth your priestly while if you ensure that now the god has them covered. Maybe, you recently had a rich class of luxury traders. Or a new agriculture branch gained prominence (Who's up for god of Quinwa or Monsanto?) May be that's how patronage of gods over specific things starts in the first place. [Answer] > > As far as I'm aware the ancient Greeks and Romans and the Norse didn't have new gods added to their pantheons over time, for example. > > > Actually, the Romans were quite promiscuous in accepting new gods. See [this](http://www.roman-empire.net/children/gods.html). > > With the vast size of the empire, there were of course many new gods from distant civilizations which the Romans learnt about. Romans didn't tend to think that only their gods were the right ones. If they heard of other peoples' gods they would think that these were real gods who watched over other parts of the world and whom they had simply not yet heard about. And so as they learned about these new gods, new temples were built to these new arrivals in the Roman pantheon. > > > Isis (Egyptian) and Mithra (Persian) are fairly well-known examples. It is also not widely realized, but the Roman pantheon was *enormous*. See [Wikipedia](http://en.wikipedia.org/wiki/List_of_Roman_deities) for a list. Roman deities numbered in the hundreds, although some of them were seen as aspects of other deities. Since Norse mythology was oral, and the Norsemen didn't build temples the way the Romans did, there is simply no way track the appearance or disappearances of gods within the tradition. All we know is what was reported in the Eddes. In general, I would argue that polytheistic religions would probably accept new gods without much fuss, as long as the new gods did not conflict fundamentally with the established gods. If the religion has been around long enough to generate a large body of established writings about the attributes and boundaries of the Known Gods, I'd expect problems, but the existence of multiple gods seems to imply limited powers and limited influences, so the "discovery" of a new god ought to be easily accepted. For instance, the Greeks accepted Zeus as a sort of head god, although he was hardly either omnipotent nor omniscient (see the divine maneuverings in "The Iliad"), so a more powerful, dominant deity would not be accepted. The Romans had Jupiter in much the same role, except that there is little Roman mythology, so there is not much basis for speculating on how the gods interacted. This did not seem to bother the Romans much - they just kept adding gods as they encountered them in the course of establishing and expanding an empire. [Answer] Polytheists are much more accepting of new gods and religions, there is always room for more. It's more like they just didn't know about this new god and maybe he/she will smile favor on me. I'm pretty sure most polytheists didn't look on Christianity as a new religion, (at least at first) but the rise of a new god. There will always be the people who don't like change (Pluto has always been a planet!) but there are plenty of open minded people too. Many are not going to be too upset about adding a new god to a pantheon. I am pretty sure that the pantheons did expand. Part was absorbing others when a new god wasn't an obvious alter ego of a current god. We mostly are aware of the 8 big ones. Looking here at the [wiki article](https://en.wikipedia.org/wiki/List_of_Roman_deities) shows that the Romans really did absorb new gods. Now, in your case it will be a little more frightening. They will have an actual visual confirmation that a new god has arrived, unlike the humans, who learned of new gods through communication with other people. This new god will be visible to all at the same time. It will certainly cause some panic. Most will have some fear of the future, but take a wait and see approach. How does this new god play with our old gods? How does it affect our lives? Some will try to gain favor by jumping on the band wagon to accept the new god. Eventually it will become accepted and many new stories will come about explaining the new arrival. [Answer] This is a bit different in how multiple gods seem to have been adapted in ancient history. Usually, a god or cult figure would enter the pantheon of the ruling culture either by adoption, if the god fulfilled a role that hadn't been done before, or was only a "secondary" duty of a major god, or the attributes of the god would be taken by one of the existing gods in the pantheon. The second option seems to be the more common one, think of the various roles the god Apollo plays: a sun god (or charioteer to the sun), healer, archer, patron of music etc. Apollo is evidently quite multi talented, but aside from being a god, the more likely explanation is various solar cults eventually coalesced around Apollo, and the attributes of these various cults were incorporated into the god we know as Apollo. Other Greek gods were similarly multi talented (Athena is goddess of wisdom, courage, inspiration, civilization, law and justice, mathematics, strength, war strategy, the arts, crafts, and skill. No wonder Odysseus had her as his patron goddess). In this particular instance, there is a physical manifestation of the new god, so sweeping the deity under the rug, so to speak, isn't possible. There would need to be a "plausible" explanation for the god to appear at this time and add itself to the pantheon, and attributes which do not belong to other gods will need to be assigned to this one (or, the god can manifest itself with *real* miracles and declare itself to be the god of whatever it wants to be). This will also cause a lot of turmoil in the priesthood, since the arrival of a new god will upset the order and hierarchy of the existing pantheon. Religious wars could be fought to determine who exactly fits where in the pantheon, and the new god will probably have a very fanatical group of followers determined to displace the former "top" god, opposed by equally fanatic believers of the "old" religion who are determined to keep the new god in a "junior" position in the pantheon. And of course there will be *some* free thinkers who will wonder if the appearance of a new moon might mean the pantheon of gods isn't all it's cracked up to be, and propose alternative religions in its place. ]
[Question] [ Reality is both cruel and unjust when it comes to the point of absorbing magical power from a slain monster: every adventurer notices the significant boost in their magical power when they defeat lesser monsters found loitering around the kingdom but pathetic gains from the high reward bounties usually issued by the guilds. This phenomenon has been called the magic scaling asymmetry problem since ancient times and remains unsolved to this date. King User VMDCCLX had to put up a decree to ban bullying of lesser monsters due to the mounting pressure from the conservation activists. I am wondering: how could the slaying of lesser monsters grant more magical power compared to monsters of higher caliber? [Answer] The more powerful the monster, the more efficiently it uses up the magic and thus the less left to boost the slayer's. It is possible that this could be counter-acted by slaying the monster very quickly, but also possible that the monster is using up the magic all the time, not just in battle. [Answer] The magical power of each and every creature is somehow proportional to the ratio between surface area and volume of the monster. $MP \sim {surface \over volume} \sim {k\_1 R^2\over k\_2R^3}={k\_1 \over k\_2}{1\over R}$ The smaller the creature, the larger the magical power MP. This is also what happens with the metabolic rate in animals: the smaller the animal the higher the surface to volume ratio and thus the more energy loss that needs to be compensated by the metabolism. [Answer] 1. Monster, especially magical, are dangerous. Slaying them require expensive ammunition and rare ingredients even for experienced groups. Even elite hunters could perish and become prey for monsters. In terms of `loot/(risk*expenses)`, hunting for (relatively) small monsters is just brings more profit because **require less expenses**. Bigger monsters don't get more precious or expensive ingredients. 2. This world is really cruel and big monsters eat smaller one... if could find them and catch. So, if you see *small monster which survive couple years*, you could sure it has some ability like invisibility or extreme speed. It means it has some gland which could provide similar ability for human (being properly extracted and refined). Tracking and killing small monsters is tricky but in general is less dangerous. If you are lucky or just have good enough equipment, you would prefer hunting for **small monsters which could get rare abilities** which big monster just don't need. Since average slayers can't differentiate monsters, they are slaying every small monster in hope that someone would have something unique. It's put more pressure for small monsters: they are not live long enough for developing their abilities and/or produce next generation. So smart people want to limit hunting like in our world hunting at spring is banned: let game to breed next generation and grow. Probably, you could combine these options. [Answer] ## Quantity of souls In this world, magic power is gained by consuming souls of magical creatures. As it turns out, the process cares about the quantity of these souls, not the quality of them. Killing a dragon allows you to absorb a magical soul. Wiping out a group of five harpies will give you five souls. But a skilled gremlin hunter can get a hundred souls if he finds a decent breeding ground of these small creatures, and all that with much less risk than confronting a dragon. [Answer] **Magical energy gained is according to the inverse of magical energy owned.** I am a newbie adventurer, armed with a pointed stick and my wits, and a codpiece. I slay a lurking GRUE. A GRUE has intrinsic magical worth of 100. My own magical worth is 2. 100 \* 1/2 is 50. A GRUE is worth 50 points for me. Lord Murderhobo has magical worth of 1000. Many and varied are the things he has killed. He kills a GRUE as part of his stretching exercises. This GRUE is worth 100 as well. 100 \* 1/1000 = 0.1 magical points for the Lord. Should I, the newbie, by clever artifice manage to slay a feral FLANGHOUND with energy of 10000 points I would obtain 10000 \* 1/52 = 192 points. Lord Murderhobo would obtain 10000 \* 1/1000.1 = 10 points. Of course the chance of me with my GRUE-stained stick slaying a FLANGHOUND is vanishingly small. Thus is it that experienced adventurers must seek ever greater adventures to receive comparable payback for their efforts. [Answer] Larger monsters *do* give off more magic-increasing energy than smaller monsters, but the sheer quantity means that it's not usable by your everyday adventurer. Imagine trying to capture a rush of water in a wineskin. If it's a trickle of water, capturing it is easy, and your wineskin is partially filled. If it's a torrent of water, your wineskin will be ripped from your hands and emptied out when the water recedes. Small monsters release a small trickle of magic power, while big monsters release a torrent -- but it's the small trickle that's useful to those nearby, not the large torrent. [Answer] The high bounties are on monsters which happen both to be more powerful and also to reward the adventurer more poorly. You don't have to tie the two together. For example: * The city was founded somewhere that just happened to have fewer powerful monsters (that's what made it a good place to found the city!) or the powerful monsters just don't like to approach the city because of the immediate and disproportionately brutal reaction on behalf of the city guard. This explains the fact that lesser monsters are easy to find. * The more powerful monsters live in an area which makes it hard to get magic from their slaughter. For example, they live in an area where the bedrock naturally absorbs magic with high affinity (so the energy released on the death of a monster is immediately drained away into the Earth). This explains the fact that the powerful monsters release less usable energy: it's not that they release *less* energy, just that they happen to live in conditions which make that energy unharvestable. [Answer] ***Magic potential differentiates as power grows:*** Magical energy as measured by gains from slaying monsters is intrinsic to all monsters. Each is born with an identical amount, but as they slay heroes, burn villages, ect. this energy goes into making the monster more powerful (just as it makes the magicians gain from the killing of the monster). A huge ancient red dragon has converted all this potential into city-killing magic might and has none left to steal. A lowly goblin is filled with energy and hasn't converted hardly ANY of it to power. Strong monsters kill others and grow stronger because of it. They also become less attractive as victims because they have less potential. Thus weak monsters are magic prey, and strong monsters are predators. Logically, these powerful monsters can no longer gain in strength without killing new monsters. So if your wizards lay off the weaklings, the big baddie monsters will step in to fill the ecological niche they leave. Conservationists need to concentrate on breeding programs, not the end of hunting. Otherwise it merely leaves more magic on the tables for the super-killer monsters to become Godzilla. [Answer] ### That's what evolution would do. Due the law of energy conservation, magical energy is obtained by converting *food*, lots of food. Smaller monsters' metabolisms require relatively little energy, and therefore they can easily eat much more than what their metabolism require and use the excess to fuel their magic. Bigger monsters' metabolisms already require a large amount of energy, and thus food, *just* to keep them alive and moving. There's not enough food to harvest without stripping the land bare. Add to the fact that bigger monsters are so powerful and tough *without magic*, and you can see how harvesting magical power would be detrimental to them: little benefit, huge food handicap. It's just evolution at work. [Answer] How can a easily dispatched (well, you can call it that) fat hens give more nourishment than strong ferocious lean wolves? Because of different balance of resources inside them that you consider useful for some particular cause - be it nourishment or drawing of magic, of course! Not every greater monster is magical - it could be greater physically instead: stronger, faster, better armored. And without a single drop of magic. [Answer] # Bigger monsters retain more magic Bigger monsters retain much more effectively the magic in their bodies even after death. That is why they are so strong during life. This means that for an adventurer it's much more difficult to draw that magical power. The main problem is that non-one has found an effective way to draw that magic easier yet. ]
[Question] [ I understand, of course, that humans evolved for this exact environment! However, if you could travel back in time 2,000 years and modify our species (without any unintended health consequences), could you prevent the widespread environmental damage we currently do? And could you do that *without* adjusting our psychology? I'm looking for high-tech body modifications (not just 'turn us into bison') that would eliminate, or at least minimize, our inclination to drive down the road toward environmental degradation. That is, how would you build 'greener' humans? [Answer] ## Make us become less fertile as conditions change...except we already do that. Slowing down the human reproduction rate overall will not work - The cause of the human reproductive boom is not our high reproductive rate (we have one of the lowest reproductive rates of any species in the world) but our reduced death rate. Population growth without limitation is exponential; no matter how slow this exponent is, at some point it will skyrocket. Like Thanos's stupid plan, reducing human reproductive rate is a temporary solution at best; at some point we will exceed the carrying capacity of the planet anyway... Unless we are able to *detect* changes in our environment and slow down *our own* reproductive rate when our population outstrips the carrying capacity of our environment. Many animals do just this, especially large predators like bears (which is why pandas are having so much trouble reproducing in captivity). However, these animals tend to become less fertile as food becomes *scarce*. The problem with doing this to humans is that we are so good at keeping ourselves fed that many are unlikely to notice the change until it is already too late. What humans really need is to become less fertile as life becomes *easier*. Which we already do. Population growth in developed countries is leveling off and in some cases (like Japan and Germany) has already started to decline. Because of this, most modern scientists agree that overpopulation is *not* a danger to the planet. As long as countries continue to develop, eventually the global population should stabilize with an average of 2 children per couple. Population growth will stop. The real problem is not the *number* of humans, but the *behavior* of humans. A global measurement of human population growth vs environmental impact gives a skewed picture, because the population growth and environmental impact are not happening in the same places. Developing countries have the highest population growth, but the smallest environmental impact. Developed countries have the smallest population growth, but the highest environmental impact. It is that latter that must be targeted to inhibit environmental damage, not the former. ## Directly or indirectly, you will need to modify behaviors In prehistoric times, there were periods of plenty and periods of famine. In order to survive, humans would stock up during the periods of plenty in order to survive the periods of famine. The problem is that even when in a comfortable environment, the human body wants to consume as much as possible in preparation for the lean times ahead. In modern times, however, those lean times never come (unless our unrestrained consumption causes them to come). So how can we fix this without modifying psychology directly? One of the biggest sources of environmental damage occurs due to heavy meat consumption. The human body craves high-energy food, and given the option (which we have now, while we didn't in the past) will eat as much of it as possible. Land clearing for livestock, emissions and runoff from farmland cause immense amounts of environmental damage. We already limit our own reproduction when conditions are too easy. If there was a way of connecting the drive to eat meat to this same part of the brain, such that developed countries were less inclined to eat meat, this would benefit the environment greatly. This can likely be done without significantly altering overall human psychology. There are other changes that can be made to make humans less inclined to consume under comfortable conditions - like reducing the need for competition - but these will likely require more invasive psychological modification. [Answer] ## The damage we do to the environment is due to our decisions so you need us to be better decision makers. ## Make the logical part of our brain a bit stronger and give us a stronger sense of humor. Most of our problems stem from choosing instant gratification and ignoring long term problems. The logical part of our brain has to work hard to override instant emotional responses, often times just getting used to justify an emotional decision rather than actually making the decision. We are better at rationalizing then actual rational thought. If the logical part of our brain had an easier time overriding the emotional (not too easy we still screw up a lot) then we would be better at taking long term effects into account. We are also suck at changing our mind. We tend to stick with the first thing we are told. One of the current ideas about what humor IS is that it is how the brain changes held beliefs. If a belief is provisional there is no issue we just toss it, but once we start integrating a belief we don't like to change it, the more ingrained the harder it is. Humor is believed to be how we change held beliefs, a mechanism that looks for internal conflict (combinations of logically inconsistent beliefs) and rewards the brain for challenging and changing them when they don't match. When two beliefs are too tightly held the conflict stops being funny and we get cognitive dissonance instead. We just ignore the problem and even get angry when attention is drawn to it. If humor reached a bit farther or cognitive dissonance was a little harder to trigger you would have humans who are more likely to change their mind when they see enough evidence instead of digging in their heels and denying the issue. Will we still screw up, of course, You can't stop that and have an intelligent species. But at least we will be more likely to recognize problems and do something about it. You can't ask for much more than this since a lot of what we do is what any animals that can does, change its environment to better suit itself. Even with climate change most of the worry is about the impact it will have on *us*. So make humans better at seeking out and solving these problems. [Answer] OK everybody seem to be focusing on *fertility*. As good a point it is, and some answers and comments reflect that, the fertility solution alone has 2 major flaws: 1. It is only temporary, you just delay the inevitable. 2. it's already happening (as IndigoFenix pointed out). The problem is that we now live a lot longer than strictly necessary to infant and nurture the next generation. I take it that all the answers towards fertility control have the tacit assumption that the underlying problem was overpopulation. So in light of that and of the point (2) above, my solution takes the problem from the other side: ## Make us (much) less resilient. At the moment we already have extremely resilient bodies compared to the whole range of biodiversity. We can survive in a wider range of temperature, pressure and gas composition, than most species (bar a few really impressive bacterias), so we can push the boundaries of our environment to a point which is 'uncomfortable' for us, but already deadly to many species. If you make us more **fragile**, such that environment modifications puts us at a direct risk (not a risk over 10 generations) and force us to do a great deal of thinking and life choice in order to survive, I would count on the collective intelligence to find a few ways to live 'greener' in a stable lifestyle in order not to have to completely reorganise society everytime we dump a few tonnes of carbon in the atmostphere (and also avoid the inevitable massive death toll during the reorganisation). This way, regardless of the actual human population level (prehistoric, current or future), the onus is on the humans to find a survivable way to handle it. Hopefully the humans have the mental capacities to find workable solutions, the only thing they needed was an actual incentive\* \*(as said above, *this is dangerous for your grand-grand-grand children* is not resonnating much with the current short term views of modern societies. But *change now or die now* might speak to more people, and the ones who don't listen will feed the ecosytem shortly anyway). [Answer] **Make us less fertile** There are a myriad of reasons why we as humans do what we do and changing a single one will make us less successful as it is that very resourcefulness that has allowed us to survive and circumvent every challenge thrown at us by the world so far. In point of fact, going back only 2000 years is leaving it far too late to make an evolutionary change to us other than fertility because a lot of what we were doing to the environment we were doing that far back. The difference between the Egyptians of old and we today isn't our approach; it's our numbers. We are spreading across the planet in numbers that the planet could not sustain if it wasn't for our science, our ways of harnessing energy for transport of food and other supplies, etc. The problem with the environment today isn't a problem of our methods so much as it is of our rate of consumption. If we were to dial that back significantly, then the planet could handle it but the price would be that within a generation there would be far fewer of us. So, don't have as many of us in the first place. If we did something to dial back fertility 2000 years ago so that even in ideal conditions, we couldn't expand in numbers at the rate we do, then we have made a great start on solving the problem. The issue as I see it is that we are the first species ever to be able to *create* our own ideal conditions, to adapt our environment to us rather than the other way around, so as a result we increase in numbers. But, if there was an increased energy cost in birthing, say, so that the absolute maximum number of children a woman could bear in her lifetime was 3 (replacement for the parents and the occasional non-breeder or fatal accident) then we are greener by virtue of being fewer. We don't need the massive energy intensive infrastructure to move food and the like around the planet, and we end up living in balance with the environment, at least more so than we do with the numbers we currently have to support. [Answer] Gather in close, wise children, sit here in the cool shade and learn more about the Olde Times of the Barren Lands. Listen to our revered New Ranger visiting our Forest today. Listen and learn. There's legends told of our ancestors, the Sun Walkers, who, before the great Change, traveled freely without covers upon the bare surface of Earth's lands and seas. These were the Sun Walkers who worried not if the Sun danced upon their bare skin; who worried not if a young one chased a butterfly out of the cherished Deep Canopy into the dangerous sun-dappled Borderlands; who worried not about careful Elder Tree care and New Forest regrowth planning. Indeed, these short-sighted Sun Walkers actively practiced sacrilegious clear cutting of acre after acre of our protective Forest lands for many generations before the great Change. The legends say in the ten years before the Change there came the First Forest New Ranger, the seer prophet with dire warnings to protect and restore what remained of the Forest lest their carefree way of life in the Light be forever changed to seeking the Dark. Warnings that went unheeded during all of the Last Sun Walker Decade. Warnings that heralded the coming of the Blister Plagues that took root amongst all the Sun Walker tribes and the coming of the Blister virus that even now lays hiding just under the skin, carefully awaiting its chance to burst forth for those unlucky enough to be caught unprepared in the Sunlight. Those of you already laden with Blister scars... look closely at your scars and see in them the ravaged, barren, wrinkled deserts of the legendary Lands in the Sun. Remember the plight of the foolish Sun Walkers and remember to give thanks every day for our sacred Deep Canopy and for the work of our many New Rangers. [Answer] Here are two genetic modifications that could be considered. 1. Gluten tolerance removed. 2. Dairy tolerance removed. The mutation that allows humanity to digest Wheat and Dairy allowed population growth to explode as agriculture was developed. Introducing additional intolerance to Corn and Rice may also be helpful. [Answer] **Give us a better sense of smell.** (I'm cribbing from Larry Niven's *There's a Wolf in My Time Machine* here, of course.) If we can't tolerate the smell of coal smoke, or of petroleum, the industrial revolution is going to wind up as a non-starter. That eliminates the more severe environmental risks our current civilization faces. ... which isn't to say the resulting hypothetical civilization might not come up with some new ones. But at least they'd be different ... [Answer] I think there is something important that must be understood : **All species are modifying their environment through their behaviour.** The widespread environmental damages that we do now is due historically to the order of magnitude of two exponential growth : first, in population and second in using energy and machines to augment our capabilities and make our lives easier, thus making a huge change in the environmental impact we have. Regarding population, in western countries, the birth rate is below 2, which means that we are not on a long term growth. This part is already more or less managed, and the number of living people should be stable on the long term. No need to modify anything regarding population in my opinion. The second exponential growth is the production / consumption we do. **(2% per year of growth, over 200 years, it's already 50 times more).** However, as you might have noticed, we don't *feel* that more rich compared to our ancestors, because we compare ourselves to our neighbour and what *seems* "normal" is slowly changing in our minds. Similarly, we don't *feel* what the world was like 100 years ago. (**That's called [baseline shifting](https://en.wikipedia.org/wiki/Shifting_baseline)** : what was considered a big fish was not the same for our grandparents compared to us, as well as what is a "hot summer" or a "cold winter", or a crowded area, or normal job conditions, etc...) This is what makes it difficult today both to : * Ask people to reduce their lifestyle (for them, it's "normal") * Make them understand the long-term impact we have. (for them, it's "normal") Now that the problem is clearer, here are two positive solutions (in the sense it wouldn't hurt anybody's ethics). We can fix it either by : * **Making people more rational** (and interested in the long-term of the species, depending of how you see people nowadays), and thus, people would base their decisions taking the facts above into account more easily, because they'll know they are very lucky and the environment in great danger * **Giving people a long-term memory** (maybe coming genetically from their parents), so that they'll remember (more or less) how it felt a long time ago. [Answer] [![enter image description here](https://i.stack.imgur.com/vS1yq.png)](https://i.stack.imgur.com/vS1yq.png) # Make humans unable to digest animal fat and protein. Animal husbandry for meat and dairy production accounts for a lot of greenhouse gas emission and growing food for animals requires a lot more land than growing plants for human consumption. Going vegan allows to feed a lot more people per square km of farmland, which means we require less deforestation and less use of pesticides, herbicides and fertilizers. # Make humans more temperature resistant. A lot of energy is used for heating in the winter and air conditioning in the summer. If humans could live comfortably in a much larger temperature range, then a lot of this energy could be saved. # Make humans able to see in the dark. Another large contributor to energy usage is artificial light. If we wouldn't need it, we could save a lot of natural resources. # But in the end it won't do much. If you don't considerably change the psychology of humans, then the human population will keep growing and will keep finding new ways to use Earth's resources to improve their comfort. So you will just delay the point at which humanity reaches the limit of Earth's resources. [Answer] **By making us as a stronger alpha predator** Humans hunt in groups, cultivate lands, manipulate objects, even grow a bigger brains because we're not come from the top of the food chain. If we can hunting solo whenever we want, the probability for us to resort to using sharp objects and fire will be lower. We won't need to develop hierarchical organization, we will be just enjoying life and roam the forest to this day. [Answer] I agree with Tim B. Fertility is humanities downfall. We form communities, it is in our blood. <https://socialmediaweek.org/blog/2015/01/5-key-reasons-people-join-communities/> A great blog that goes more in-depth here. As the communities grow through pair bonding, each area expands exponentially. Seeing that you do not want any psychological tampering, making pregnancies rarer would, theoretically, do the trick. [Answer] Taking up IndigoFenix' point, probably the most useful mod would be to re-engineer the gut to digest cellulose and not animal proteins (not sure that this is chemically feasible, though). Ultimately, it's all doomed to fail. Unless you have a way of winnowing the population on a constant basis, it will eventually creep up to the point that feeding us all damages the environment in a catastrophic way. Those who say we should limit reproduction are missing the point - it's not our reproductive capacity that has caused our population to burgeon, but our adaptability. We can, and have, adapted to every environment on the earth (and off it!) but these days we do it mostly through the application of technology. If you want to save the planet by tinkering with humans, the best thing to do would be to make us no smarter than the rest of the animals. [Answer] As most of the other answers are focused on population control as a solution, let's take a more proactive approach, seeding our genome with a few time bombs. Have your time travelling geneticists encode a few pandemic capable viruses with high lethality into the junk sections of our DNA and then set up triggers to release them when needed. If each plague is triggered by a different indicator of environmental decline (famine, drought, pollution, radiation,...), then every time we start to mess things up, along would come a plague to slap us back down and teach us humility. [Answer] **Self-regulating fertility** Make humans break down if they live in too cramped quarters. Increase this to a degree that even Rome could not have existed. There are side effects, however. First, humanity disperses into smaller villages, towns get depopulated because people *just cannot stand being in those crowds anymore*. Second, those smaller communities are less resilient to attack. The loss of life and commodities means that there will be less surplus for luxury activities, in particular focussed research. So... expect the Industrial Revolution to happen much later, or maybe not at all. Third, humanity will still grow and fill the world. It will not be as concentrated, but ultimately, its *global* ecological footprint will exceed sustainability. It will just happen later. (This is a potential plotpoint: Avoid ecological disaster, just to see a different disaster looming at the horizon.) Fourth, evolution will work against you. People will live in overly large communities anyway (just because the advantages are so large). They will suffer, they will die, but they will still come, just because suffering in a city is slightly less horrible than dieing in yet another raid. Which means you have a breeding ground (literally!) for people where your mutations are reverted. One thing to combat this evolution is to get the raids under control. Historically, raiders got eliminated once police forces could communicate faster than raiders could move - i.e. with the invention of the semaphore. So... if your hypothetical benefactor forces humanity into dispersion, he should consider giving them that idea. A semaphore is not terribly difficult to build, it is mostly about being dedicated enough to work out the tricky optimizations and improvements. The other disadvantage of dispersal is that intermediate products will have to be carried over longer distances. It will shift economic advantages, but I do not think that it will eliminate technological progress (of course, I may be wrong). ]
[Question] [ **Preface** With all technology discovered prior to this question, on today's planet, there are still some things we have not observed - which may be used to justify introducing new life forms, right here at home, in a story. --- **There are a LOT of unexplored places on Earth** > > * We've explored [less than five percent of the ocean](http://oceanservice.noaa.gov/facts/exploration.html) > * We see evidence of [potentially new organisms but can't always locate them](https://en.wikipedia.org/wiki/52-hertz_whale) > * Plenty of undiscovered species [do exist](http://news.nationalgeographic.com/news/2011/08/110824-earths-species-8-7-million-biology-planet-animals-science/) > * Many rainforests have areas that are either uninhabited or that [modern scientists haven't been through](https://www.youtube.com/watch?v=sLErPqqCC54), ruling out discovery in > the "traditional" sense but allowing large creatures to go unnoticed > by science > > > --- **To be clear** I am defining "undiscovered species" as: * Somewhat unique. Cannot be a subspecies or a division of a well-known species into groups that are somewhat similar to each other. * Unbeknownst to or denied by modern scientists. Can be seen by isolated or indigenous societies. * Lacking observed evidence of existence to the point that any actual evidence found is explained by some other phenomena. Like if [the bloop](https://en.wikipedia.org/wiki/Bloop) was an animal and we brushed it off as ice moving, or like if [this thing](http://natural-environment.com/blog/shell-oil-company-catches-alien-squid-on-camera/) wasn't actually a known animal, or if [this thing](https://www.youtube.com/watch?v=cGk-yuYMAms) wasn't a sleeper shark. --- **So the question is** **Given the above information, how large can each of the following organisms plausibly be on Earth in 2016 while remaining undiscovered with current technology?** * **Plant, fungus, or similar species** * **Land animal** * **Aquatic animal** --- \*I will not accept "*it will probably be..."* I would like calculations or references as opposed to speculation, please. --- **Edit:** In response to all answers - I ask "how large can they be" not "what is a size they could be". I do apprciate your answers but every one seems to say "this is a large thing we've seen so an organism could be at least this large". What no answer **does say**, as the question asks, is "based on the ways we observe the world, an organism could be *at most* this large". [Answer] # Land animal First, the answer depends on your definition of 'undiscovered'. If you mean 'undiscovered to Western scientific classification' then it is quite possible that a currently known sub-species will be elevated to species sometime in the future; much like the African Elephant is in the process of being split into two species (the original bush elephant *Loxodonta africana* and the forest elephant *Loxodonta cyclotis* which a recent DNA analysis indicates is [more closely related](https://en.wikipedia.org/wiki/African_forest_elephant) to an extinct European Elephant than to the bush elephant) If you mean 'undiscovered by Westerners in general', the winner might be the [kting voar](https://en.wikipedia.org/wiki/Kting_voar), if that is non-mythical and also non-extinct. The wikipedia page I linked is pretty skeptical, but consider that a different distinct bovid was found in the same region in 1992, the [saola](https://en.wikipedia.org/wiki/Saola). If you mean 'undiscovered by any people'; well, then it would have to be something Antarctic, or tiny, because people are everywhere. Its hard to even say what would constitute 'undiscovered' in that sense, so I'll let it pass. # Aquatic animals The first specimen of the [colossal squid](https://en.wikipedia.org/wiki/Colossal_squid#Largest_known_specimen) was captured in 2007. Since it is only recently that the [giant squid](https://en.wikipedia.org/wiki/Giant_squid) and colossal squid were distinguished from each other, it is plausible that there could be another large squid type hanging out in the deeps (Titanic squid?) Sleeper sharks are also large and poorly known. The [Southern Sleeper](https://en.wikipedia.org/wiki/Southern_sleeper_shark) Shark was determined to be distinct from the [Greenland](https://en.wikipedia.org/wiki/Greenland_shark) and [Pacific Sleeper Sharks](https://en.wikipedia.org/wiki/Pacific_sleeper_shark) only in 2004. The sleeper shark niche seems like a plausible place to find a new species. Another shark option are deepwater plankton feeding sharks like the [megamouth shark](https://en.wikipedia.org/wiki/Megamouth_shark). The megamouth has only been discovered in tropical regions; there could be a polar variant hiding in deep oceans. # Trees Given the incredible diversity of tree species in rainforests, I feel confident that there are 30m+ undiscovered trees hiding in the darkest Amazon or Papua New Guinea. # Fungus The [giant fungus in Orgeon](https://en.wikipedia.org/wiki/Armillaria_ostoyae) was hardly suspected to exist until an [investigation in 2003](http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev3_033146.pdf). It seems pretty likely that such a fungus could exist elsewhere in the world without being noticed. A plausible location would be in the mountains of southern Siberia or Mongolia. They are sparsely populated and have a climate generally like that of Malheur National Forest in Oregon. Another option would be the lower Andes in Chile and Argentina. Of course, looking for the same kind of giant fungus might blind us to the possibility of a different kind of giant fungus. Might there be huge fungal colonies collecting nutrients from rainwater washed underground from a lush rainforest? It could be in the [limestone caves](https://en.wikipedia.org/wiki/Phong_Nha-K%E1%BA%BB_B%C3%A0ng_National_Park) under jungles of Vietnam, the [cenotes](https://en.wikipedia.org/wiki/Cenote) of the Yucatan, or even in the giant underground [counter-Amazon](http://www.livescience.com/15849-underground-river-discovered-beneath-amazon.html) ['river'](http://www.bbc.com/news/science-environment-14693637). [Answer] There is an island in the Andaman Sea where the [human inhabitants literally kill on sight](https://en.wikipedia.org/wiki/Sentinelese_people) any human being that sets foot on the island. They are living a Stone Age tribal existence, but we don't know anything about their language and culture, because anyone who tried find out got dead before learning anything. Whatever animal species exist on that island have been "discovered" and described only by those Stone Age natives. Just about anything might be living there. As long as it can survive alongside a tribal human society - megafauna are probably out, for example. The archaeological records show that megafauna have never survived the arrival of human beings. But anything regular-sized (up to the size of an elephant) would be completely feasible. If you want to know the theoretical maximum size this undiscovered land mammal could be, it will depend if you want it to be a mammal or not ([heat dissipation becomes an issue before biophysical weight/mass limits kick in](http://www.askabiologist.org.uk/answers/viewtopic.php?id=6836)), and whether it has live young or lays eggs. There is a [summary of research into size limits on sauropods](http://onlinelibrary.wiley.com/doi/10.1111/j.1469-185X.2010.00137.x/full), which explains other factors like how much they chew their food and how long their necks are ... The [contraints for sea animals](https://worldbuilding.stackexchange.com/questions/317/is-there-a-maximum-size-an-ocean-bound-creature-could-grow-to) are admirably covered in the answers to this question. I can't see any upper limit to the volume of a fungus, because [entire aspen forests are a single individual organism](https://en.wikipedia.org/wiki/Pando_(tree)). The largest on record is 106 acres, and there would be no practical obstacle to it continuing to expand. Of course, if it couldn't live in sea water, your fungus would be constrained to the size of whatever land mass it was on, and, to remain undetected, would need to be under the surface of the ground, except for its "flowers" - whatever shaped thingy it pops up to spread its spores from time to time. [Answer] ### I believe that the calculations you are asking for are impossible. One reason is the difficulty of defining discovery. Take [Bigfoot](https://en.wikipedia.org/wiki/Bigfoot). Has he been discovered? Plenty of people believe in him. Or does it only count if a reputable scientist bags one and carries it off to be stuffed in a museum of natural history? And what about species that were only recently discovered to be *separate* species? ### Empirical evidence provides a lower bound. Every now and then, scientists [discover a new species](https://en.wikipedia.org/wiki/List_of_megafauna_discovered_in_modern_times) or accept the descriptions by an indigenious people that were previously discounted. * A new [monkey](https://en.wikipedia.org/wiki/Myanmar_snub-nosed_monkey) in 2010. Half a metre. * A new [tapir](https://en.wikipedia.org/wiki/Tapirus_kabomani) in 2013. More than a metre. From that we can [state with some confidence](https://en.wikipedia.org/wiki/Bayesian_inference) that an undiscovered, human-sized mammal might exist. [Answer] I'm not sure if the [Soala](https://en.wikipedia.org/wiki/Saola) meets your strict definitions, but it was discovered in 1992. Also, [Mount Mabu](http://www.cntraveler.com/stories/2014-05-05/mount-mabu-mozambique-maphead-ken-jennings) is popularly known as the "Google Forest" because it was found via satellite mapping by a team looking for previously unexplored regions. It's plausible that as-yet unknown species could live there. TL;DR - it's totally plausible in my opinion. [Answer] It seems impossible to calculate a maximum sized organism (animal/plant/other) that could be still undiscovered, because it seems possible that an organism bigger than any that could possibly live might remain undiscovered. For example, a hypothetical deep sea organism - plant, animal, or other - could grow to the size of a mountain - kilometers or miles in each dimension - and stick to the ocean floor. Survey ships could pass over it with sonar scans and record it as an undersea mountain with unusual texture. And who knows how long it might take for anyone to be interested enough to investigate more closely and discover it is a life form. What about a giant sea monster that comes to the surface? If it surfaces away from normal shipping lanes, it might never be seen or photographed. There is no radar system that constantly scans the entire surface of the sea to detect ships, is there? Are there satellite systems that constantly image the entire surface of the Earth and record it? And if so, what is their resolution? How big would something have to be to certain to be detected? I believe that under the right circumstances, organisms miles wide could come to the surface periodically and not be detected. What about a sea creature that doesn't make songs, calls, echolocation and other vocal noises like whales do? Could underwater hydrophones detect the sounds it make swimming if it was big enough? And if so, how big would it have to be to certainly be detected? Thus it seems possible, under the right circumstances, for plants, animals, and other organisms as big or bigger than any known to exist to remain undetected today. [Answer] A few years ago I was amazed to learn that something larger than the Giant Squid, the [Colossal Squid](https://en.m.wikipedia.org/wiki/Colossal_squid) has been discovered. Now the giant squid is found dead in fishing nets, but spotting a live one proved very difficult. I saw on TV one expidition thought it would be a good idea to go down in a bathesphere and just watch out the window—they *heard* whales in the area but didn’t see them, either. The larger Colossal Squid was “spotted” in the stomoch of a whale in the early 20th century, but no intact specimen found until 2003. If you had asked this question just a few years ago, would you beleive the answer would be 500–750 kg? We *don’t* spot them in fishing nets or floating dead because of their habitat and lifestyle. This suggests that very large and completely unknown animals may live at similar depths, and their physiology is such that they *sink* when they die. The lifestyle causes it to be *large*. These squid hang out below the deepest that normal fish can see, and using a *huge* eye watch for shadows against the glow from the surface. Then they need a huge *reach* to grab what they spotted. So, another unrelated squid like that, or some other animal that makes its living in a similar way will tend to be very large. Perhaps they have a slow metaboloism and eek out a living on rare dinner, but they never stop growing and live for hundreds of years. How large could it possibly be, without us knowing about it already? I think it would be the *total biomass* limit, the size multiplied by the number of indivuals. If some unknown population was large enough to make a dent in the prey population, we would notice. [Answer] The Sentinelese are an indigenous population residing on an Island near India. [According to wikipedia](https://en.wikipedia.org/wiki/Sentinelese) they remain "virtually untouched and uncontested by modern civilization" and they have met near all attempts to make contact with violence. The Indian government has heavily discouraged to attempt to access the Island they reside on or make contact. Perhaps you could work that into a story. [The wiki page for "Uncontacted peoples" might interest you.](https://en.wikipedia.org/wiki/Uncontacted_peoples) ]
[Question] [ Assume a fairly futuristic scenario where we can deal with the energy requirements of handheld laser weapons and the realistic creation of plasma ammunition etc. From what I understand a plasma gun will shoot a ball of plasma like a projectile, which provides a little bit of kinetic energy and "burns" its target. A laser gun is just a continuous beam of energy that burns the target for as long as you fire it. What exactly would be the advantages of one over the other? Lasers obviously don't burn after you stop firing, but they are more "instant" (traveling at the speed of light rather than an ejected projectile). Do they burn better than plasma? They are also silent and invisible. Also, would a plasma gun hold any advantage over regular kinetic weapons? Would they have less of a kinetic impact? Less instant kill potential? Is the burn effect worth it? I've tried Googling a lot for comparisons from a somewhat scientific perspective, but I usually just end up finding threads about people comparing the stats of plasma vs laser guns in a specific game or something, which obviously is not what I am after - if anyone has got useful links for me to read I'd be happy about that too. [Answer] Plasma weapons are a popular SF concept that just won't go away. They are encountered in such diverse places as the original Star Trek TV series, and the Babylon 5 TV series. They play the role of a futuristic flame-thrower. Their main draw-back is that they won't work. Plasma is the so-called "fourth state of matter", and is basically hot air. When we say something is hot, we're actually talking about the speed with which its individual component atoms wiggle around. Room temperature gas moves at about 500 m/s. Obviously, plasma is really really hot. That is, it is a gas heated to temperatures comparable to the interior of a star or the center of a thermonuclear explosion so that all the atoms are ionized. Unfortunately, according to the [virial theorem](https://en.wikipedia.org/wiki/Virial_theorem), the plasma wants to equalize its internal pressure with the external, i.e., it wants to expand into a diffuse cloud of nothing. And since it moves really really fast, this means that after the plasmoid travels for one second, its diameter will be approximately five thousand kilometers, i.e., it has dissipated into nothing. [More cool info here](http://www.projectrho.com/public_html/rocket/spacegunexotic.php) So I'd go with lasers. :) For extra oomph, make them gamma ray lasers. [Answer] The open-source game [UFO:AI](http://ufoai.org/wiki/About) has a plausible-sounding design for both plasma and laser weapons, and the in-game description has a very detailed hard sci-fi explanation about how they work. All the advantages and disadvantages of plasma and laser weapons are presented in detail, both in the descriptions and their in-game functionality, although the later is a little bit abstracted. A very powerful late-game weapon is actually superior to the alien's plasma rifle, as it's a normal kinetic weapon with a projectile including a very little amount of plasma, designed to burst after entering the target, working both as a shaped charge to punch through armor, and as a very advanced version of the real-life expanding bullets. The [plasma weapons](http://ufoai.org/wiki/Translation:Plasatomizer_txt/en) involve a solid protective shell which is designed to burst after traveling for a short while. They have a small range, because despite the projectile traveling fast the plasma eats through the casing very fast, and due to its lighter weight the accuracy is also lower than of traditional firearms. What it excels at is its high stopping power. Whoever is hit, feels the pain immediately. The [laser rifle](http://ufoai.org/wiki/Equipment/Primary_Weapons/Laser_Rifle) uses a type of [chemical laser](http://ufoai.org/wiki/Translation:Laser_txt/en), has very high accuracy and a long range, no recoil, but with the added problem of having no sudden impact, therefore a lower damage, and that they require some time on the target, effectively reducing the damage due to the shooter's inaccuracy as the beam might wobble on the target. Basically, compared with traditional firearms, the plasma and laser rifles actually represent two completely opposite directions, instead of being almost interchangeable with each other compared to the traditional firearms. *I'm not suggesting to completely copy these designs from the game I mentioned, but it might be worth taking a look at, as the developers obviously put a lot of though and research into it.* [Answer] While shooting plasma as projectiles doesn't work, using lasers to turn the air into a plasma has interesting applications in weapon design. If you want an actual laser weapon it's advantageous to deliver as much power to the target as possible. Unfortunately, when light travels through air ti interacts with it causing heating and light scattering. Once the beam has high enough power density, it will heat the air into a plasma, which interacts with the light much more strongly. This effectively creates a maximum power delivery to the target as any additional power output by the laser just goes into heating the plasma. However, the plasma does create another possible energy delivery mechanism, as plasma is conductive. If one fires two high powered lasers at a target, they could be used as wires in a high powered version of a taser, where rather than being a non-lethal weapon it's an insanely high powered tank exploding weapon. However, due to the natural tendency for air to breakdown into plasma under high electric fields it's likely that beams would have to be far enough apart that the weapon could not feasibly be considered a handheld weapon. (unless it's being wielded by a giant or a mech suit.) [Answer] Self contained plasma bursts are possible, as Randy Curry recently proved. Now his experiment only went two feet, but it's proof of concept. <https://www.youtube.com/watch?v=T5sIPJL_6F8> Other problems with Plasma Weaponry might still hinder development, but plasma dispersion is not one of them. [Answer] For plasma weapons one would probably be shooting either skyrmions (knotted magnetic lines that the plasma follows or a very past non-contained plasma (see the SHIVA start project). In either case, the relative mass is less than that of a bullet, the "net" kinetic energy involved would either be small or transfer in-efficiently, the compression and then sudden expansion of the plasma would be the main damage effect. This can be easily done today (though it is against the Geneva convention on sub 12.5mm expanding or exploding bullets) so there seems to be little advantage (beside possible weight and logistics depending on the power source and ammunition). Lasers are different. First, it depends on how you wish to cause damage. As far as I can find the most effective when power is not an issue is a rapidly expanding plasma that is generated by a laser. The US did testing on both lethal and non-lethal versions (Pulsed Energy Projectile (*PEP*) and Pulsed Implosive Kill Laser (*PIKL*)). Such a system has little recoil (mostly from expanding air in-front of the muzzle) and has the same advantages and disadvantages of any laser system (logistics mostly, with the weather being an issue fro targeting). Overall there is very little use for a small scale laser weapon or plasma weapon. Most kinetic weapons today can perform the same and have less significant draw backs. Logistics is the biggest win and so in cases when that is paramount then it would be better to have a laser or plasma weapon, and since a plasma weapon and laser weapon are the most effective when having similar terminal ballistics (photistics?) the winner between them would be plasma due to its (most likely) superior inflight characteristics (less susceptible to weather effects). And while kinetic weapons may change the way that they acclerate (powder, electro-magnetic, gravity, etc.) they are still overwhelming more effective. [Answer] In favor of lasers: * The output of a laser is massless; all you need is the energy storage, no material for your "ammunition". * Lasers move at the speed of light; you cannot dodge a laser (though depending on the power and wavelength you might be able to find cover before you're permanently damaged) * Lasers are unaffected by wind and pure range. * There's no theoretical limit to the power output of a laser; plasma has to be contained or buffered in some way which limits the power output. In favor of plasma: * Adding mass means there is some heat transfer by conduction and convection, instead of merely radiation; Whenever there's matter to readily conduct or convect energy, the transfer of that energy into your target tends to be more efficient. * Plasma, having to be magnetically "bottled" to travel out of the weapon any practical distance, would be better buffered against the transfer of energy to the surrounding air, while a laser would have to "burn through" the air and anything it contained (fog, dust, smoke) which is the major source of attenuation of energy. [Answer] I'm always surprises at people going "plasma cant work!". Imagine this: "I've got this great idea for a tank penetrator. You use something heavy that liquidises under pressure and shape something around it so that this cuts like a heated waterjet through the armor". "yeah", says his buddy, "but lead will deform upon firing and using some kind of magnetic system to keep it together, pressurise it and aim the jet won't work!" To which people even during the world Wars replied, "we could also use something less outlandish like the materials we have lying about for a hardened shells that does exactly that". Heat up the plasma while in a container like VSZ suggested in his post. Use a material with a high temperature resistance like Tungsten, or since you arw talking future tech use a Graphene shell (withstands a bit more than the surface of the Sun) and encase that with some insulator since Graphene has this nasty habit of being one of the best heat conductors known to man and losing heat is so annoying. It does make it easier to heat up the plasma in the first place. Once it hits and the plasma is released plasma has this nasty habit of expanding rapidly. We usually call this an "explosion". To maximise that, engineer the capsule to break open only at the impact site, creating an instant shaped-charge sending Hot plasma through the opponent. As for laser weapons, Atomic Rockets (<http://www.projectrho.com/public_html/rocket/sidearmenergy.php>) points out how lasers need to be very focused to work and lasers are harder to keep together across a distance than people think when talking about killing people with them. The best method they come up with is firing 1000 laserpulses in about 0,01 seconds. Each pulse is a joule or more, and turns the surface of your target to vapor or plasma. This plasma expands rapidly in a miniature explosion, most of which goes directly in the laserbeam. To prevent the plasma from soaking up energy meant for the target you use the pulses. Each miniature explosion rips part of the material around it away, causing large holes in your target each pulse. However this is unlikely to be silent. Your PC isnt silent because it needs cooling down, you are blowing away massive amounts of energy and even at its peak you have to assume no more than 70% to 90% of the energy is used for the laser and the rest is waste, and thats extremely generous as most estimates are more around 50%. Theres also the problem that you turn everything in the laserpath to plasma, including any dirt on the lens which will damage it unless its from a high-strength and -heat resistant material, but it wont be silent. ]
[Question] [ I'm trying to figure out what a huge swimming ark that is able to support maybe 10.000 people would look like. It's for a P&P campaign. And please excuse any bad grammar, spelling or poor word choice, I'm not a native English speaker. **The setting:** * The world is covered basically entirely in water (think Waterworld, the movie). I assume that also means that there are more rainfalls than in our world. * Magic doesn't exist. * The ark was being built with technology that was available during the industrial revolution, but I'm flexible about this. Science could have advanced in a different order in this civilization but they definitely didn't have lasers e.g. * The ark has been on its journey for a very long time now, let's say 300 years and has had no contact with any outsiders. That means that it has to be entirely self-sufficient. It also means, that society and culture have deviated quite a lot since it left. Most people have no idea what their ancestors life was like before they left their home, or when and why they did it in the first place. Many machines broke during the time and there was no one to repair them because they didn't have the replacement parts or they forgot how it works. * And finally, the lower decks are 'lost'. They are off limits to the general public and swarmed with monsters. They are basically dungeons where adventurers can go and try to find valuable equipment or books or whatever. But what would such an ark look like? It doesn't need to berth or navigate very well and it is much larger than anything ever build in real life, so it could have quite the different shape than conventional ships. E.g. how high would it be and where is the waterline? **Rare resources:** * Sunlight is one. Maybe they would try to build a lot of relatively thin towers to maximize surface and get more sunlight. But then, why don't you see that in real ships? (I don't actually know anything about ship design though, hehe.) Living space on the top deck would definitely very coveted, reserved for the government and rich merchants and the like. Which brings me to the next point. * Space. The ark would probably be tightly packed. People would be living in tiny apartments like in Tokyo City. Poor families would live in the lower decks, the rich would display their status by living on the top floor. Towers would emerge automatically from this system, unless prohibited. But would they own it or rent it? I think it would make sense for the government to own the entire ark and collect rent, but there may be some exceptions. Also it may be difficult to collect rent in some of the lower decks where crime lords could be the actual rulers. * Fresh water. Unless there is a good way to remove the salt from seawater, they would have to collect rainwater. So I think they would build big awnings collecting the water and reservoirs to store it in. But the awnings would block the sunlight so they would only be put out during rainfall. * Air. The air in the lower decks would probably be pretty thick. Careful ventilation shaft would be constructed to ensure an optimal circulation. Maybe they could have something like the $CO\_2$ scrubbers they have in spaceships? * Food. I'm having a hard time imagining how they would provide enough food for everyone. In medieval time, most of the land was just farms producing food but in this case this is just not possible. So if they use agriculture they would need a plant that has a ridiculously fast agricultural cycle. (And possibly a plant that doesn't require a lot of sunlight so you can grow it beneath the surface.) Maybe they could have small floating islands dragging behind them to grow their food. But these island would be vulnerable to storms and high waves. So maybe plants that can grow in saltwater like mangroves that also bear fruit? And maybe it is possible to grow some plants on the hull underwater and there are occupations like pears divers who harvest them. Also, obviously they would fish a whole lot. * Power. You would probably want some mechanical part in the ship that require power (like pumps). You can't burn fuel because it would run out so maybe they have a lot of wind turbines? * Waste. Ok, that is kinda the opposite of a rare resource but it has to go somewhere. Organised plumbing is necessary. Even in the lower decks disposing your waste improperly would probably a serious offense. They would probably use it to manure their plants. Recycling would be a big deal in general. You can't get anymore metal than what you started with, if something gets thrown overboard and it doesn't float, it's probably gone for good. Getting new wood is not a problem in principle, plants get their carbon from the air, not from the soil. **Dangers:** * Fire, definitely. I'm not sure how the ship survived for so long without a major fire breaking out. What would fire prevention and fire fighting techniques look like? * Leaks. I'm laughing at the idea of some ignorant fools trying to build a well. I guess the hull is just build very sturdy, and that's that. I'm also wondering what sort of social structure would emerge from this. In the beginning there would most definitely a powerful government. Both because it's necessary to guarantee the survival of the colony and also because only a strong government would have been able to build the ark in the first place. But over time it could have lost a lot of influence. This is, in a way, required since the fact that the lower decks have become dungeons is a non-negotiable feature of the setting. I'm also having trouble imagining what the typical job would be that you can have in this world. And I probably overlooked a lot of details that would change from the '3D-ness' of the whole city. There wouldn't be just streets there would be a lot of staircases, pulleys, chutes, (possibly) elevators and the like to make transportation between floors easier, kind of like a modern shopping mall. By the way, I think inside the ship you wouldn't really notice that you are on a ship, it would be too large to sway noticeably. These are my thoughts so far at this moment. How feasible is this setup? What did I miss? [Answer] A massive city-ship would be difficult to keep afloat for so long. You might get away with the city being built in sections, with doubled bulkheads between and massive gears used to raise a single massive section at a time for maintenance. So maybe more like a tightly-connected raft of ships where you can effectively dry-dock one section at a time between the others. The hull might be made of some kind of reinforced super-concrete (fictional invention necessary for a ship that large to be built at all much less with industrial revolution technology, with the added necessity of repairing at sea without external resources), with only vital parts like the gearing and hatches made of brass (iron is too prone to corrosion in marine environments). Most food would need to come from the sea - fishing, kelp harvesting, maybe big aquaculture pens set up around it as well or plenty of long oyster ropes (ropes just dragging through the water covered in oysters - tricky aquaculture but probably worth it for the meat and the shells). Sending out whaling boats would be of vital importance - whales could produce great quantities of fat for oil or lubricating grease, huge sheets of leather for sails or tarps, sinews for ropes or nets, meat, intestines for water-tight containers, large bones, etc. After so much time, I would expect most things to be made from these resources, with any metals being exceedingly precious, and wood being nearly as valuable. The top of the city would need to be used for farmland - citrus trees would be especially valuable for both food and wood (though still little of that as trees are slow growing). The growing material could be the organic waste from the city keeping it richly fertile. Rainwater would probably be the most vital resource of all, so efforts should be made to capture every bit of it and funnel it down to cisterns. You could consider growing edible saltwater plants (spartina, orache, etc) in massive greenhouses and collecting the condensation on the glass for fresh water, but that much iron and glass work may be a bit much. Maybe a colony of trained pelicans doing some extra fishing work and for some harvested eggs. Large air scoops could capture the wind to funnel it belowdeck for ventilation, and putting a windmill in them could provide power as well. This could be mostly mechanical power for bilge pumps or workshops, but I would advocate for some primitive electric power as well to split water into oxyhydrogen gas for recycling metals or glass, or a lime kiln (use barnacles or oyster shells in a kiln to produce quicklime for concrete or plaster). Crude electrics are possible even with fairly primitive technology, so this shouldn't be hard to work into an 18th century environment. The structure of the ship should be in large holds, each hold being one big open area with some metal structural braces scattered throughout - interior walls could exists, but not being structural allows flexibility in use and significant changes over time. This allows better variability in shanty-towns, workshop neighborhoods, etc. Perhaps 15' high and several hundred feet across each, with maybe a dozen holds per 'city block', and 20 levels from top deck to bottom? Engineering wise this is absurd, but with a few dozen blocks it gives you the space you would need for a floating city complete with adventuring dungeons. Socially speaking, I'm looking at it in a medieval way - the engineers keeping the ship in working order (clergy responsible for the saving of mankind), with whale-hunters being the knights (skilled specialist athletes with expensive equipment and potentially lethal jobs), all supported by a wide base of peasants doing the grunt work of kelp-farming, barnacle scraping, fishing, crafting, etc. Plenty of church vs lord politics possible and maybe things have gotten bad because of peasant revolts - they don't understand the implications of poor maintenance, so it seems like a lot of work for no obvious benefit since they don't see the counterfactual of a city-ship actually sinking (if they believe it is even possible), and they resent the engineers getting so much for 'not doing anything' but sticking their noses in books (weird things of no use and maybe of great evil depending on how superstitious the people get). Maybe a third of the decks will be below the waterline - this means no real lighting aside from precious oil lanterns (whale oil is expensive but the lantern itself would be priceless), so they will most likely be completely abandoned or only used for long-term storage of cast-off materials or whatnot (one would not need to tell people not to go there - the extreme expense of artificial light and the foul air would probably keep everyone out by nature). After a few generations, what is in these fetid below-water holds would have been completely forgotten or maybe some inhabited by people shunned by the rest of the population and living a mostly blind life in dank moldy sewer conditions (being forced to live down there would drive anyone into a murderous rage at surface dwellers). Over time, the mechanics for raising some sections have failed. Maintenance has not been done properly for a generation or two, and holds have corroded and have been filling with water faster than bilge pumps can compensate, and are now areas abandoned to giant crabs, giant beetles, sea serpents, giant leeches, octopuses, etc. which have come in through the holes in the bottom and are living in half-flooded holds at the lowest level. Perhaps opening a bulkhead door to enter into a section has started releasing the air pressure which has kept some of the water out - one that was opened, the water is flooding in farther and farther, so they have time pressure to find/fix whatever and get out. Every additional bit of water taken in brings the ship that much closer to sinking, so it is imperative that lifting mechanisms get fixed and monsters cleaned out so that section can be repaired. Opening the hatches allows more air out, letting lots more water in, so the hatches need to be kept sealed as much as possible, which also leads to suffocation if too much time is spent down there. [Answer] Going in a different direction from everyone else, I'd look at how a ship will transition towards living indefinitely on the ocean. Essentially, this will move towards eliminating all non-renewable resources, which would include things like plastics and metal. Ultimately, all resources would come from the ocean. **Basic Resources** Your basic resources will be sea creatures, algae, sunlight, ocean garbage, and anything that exists on the ship. Anything that can rust or break down over time will become increasingly rare and hard to get. Things like lime trees, on the other hand, can be grown from seeds. Fish would provide meat, as well as bones and sinew, which could be used for sewing and cord. Birds would provide the same, as well as feathers. Lime trees, and trees in general, could provide wood, but would be comparatively slow growing and take up space. Trees sequester carbon from the atmosphere, but ultimately require nutrients from the soil as well. I would expect wood to be available, but expensive. Ocean garbage would contain things like bits of derelict ships, old plastic barrels, and free floating buoys. Tangled shreds of old fishing nets and line could become valuable resources as shipboard resources start to run out. **Livestock** Cows would be an unrealistic animal to farm on a ship. However, there are other types of life forms that could effectively be farmed. At a most basic level, organic waste tossed of the ship will attract large schools of fish, which can be harvested for food. These fish could potentially be penned and farmed, though such pens would be at high risk during large storms. Seals could also potentially make a good form of livestock. They can range through the ocean to find food, but wouldn't be able to run off, as there is no solid land for them to move to. Whales or dolphins would only be an option if there was a way to keep them around. From seals, ark-dwellers could obtain skins, bones, sinews, milk, and fats. Fats could be used for insulation, lubrication, cooking fuel, and light. **The ark** Initially, I would expect the ark to take the form of a large, modern ship, such as an oil tanker or a cargo ship. Over time, repairs would have to be performed using natural materials, as initial repair supplies run low. Even with natural materials, though, the deepest levels of the ship may be too far under the surface of the water to repair. Some flooded compartments would need to be abandoned. These would be infested with sea life, but would contain valuable resources that adventurers could delve the depths to seek out. Sealed compartments could maintain air pockets produced by algae. Over time, additional flotation would be needed to keep the ship up. The original ship could be rafted together with large rafts and floats made up of seal skins and bits of sea waste to keep it floating even as the original hull develops leaks and holes. These large, single-decked additional rafts would greatly increase the area of the ark, but would be much closer to the water, and hence be at greater danger of being swept by waves during violent storms, especially initially. **Ark economics** Resources would be gathered by farmers living on the rafts, and probably processed into goods on the relatively stable main ark, which I suspect is also where all lime trees would be grown. Other resources would probably be harvested by small boats travelling away from the ark, maybe even for days or weeks at a time. These boats would comb a large area for bits of sea trash to bring back to the ark. Initially, machinery on the ark would probably be the basis of manufacturing, but as time progressed and people became more comfortable with life on the open ocean, and as these machines broke down, hand-made goods would become more common and higher quality, and these original industries would fade in prominence. **Economic classes and governance** Wealth, of course, has always generated more wealth. There will be people that work on the rafts, pulling fish out of the water and scraping algae and barnacles of their undersides, and there will be people that own the rafts (and hence all of that delicious algae). There will be people who make a living trying to milk ornery seals, and people who own the seals. Is suspect that the safest, most insulated areas on the ship would be home to the most wealthy, followed by people who live on the top deck, and finally by people who live on the rafts. Social mobility would be limited, with only people who are exceptionally skilled craftsmen, scouts who are lucky and find a particularly valuable piece of floatsam, and brave individuals who plumb the depths of the hull for riches being able to move up in the world. In essence: the ark would be the castle in the center of a feudal society. However, over time, as the rafts become better constructed and more seaworthy, raft dwellers would probably become discontented with their lot and seek to break away. The ruling class, of course, wouldn't want to see their valuable algae beds and barnacle farms go sailing off on their own, and would do everything in their power to suppress this. Religions would form, venerating the ship and promising damnation towards anyone who sailed away. If nothing else worked, enforcers could be placed on the rafts to make sure that nobody tried to make off with them, with limes a carefully guarded commodity to discourage flight. Perhaps, after 300 years of floating, this kind of pressure is coming to a head, and society is about to break apart... **Addendum: the living raft** Another possible food supply / building material would be seaweed. Specifically, forms of seaweed which form gas-filled knobs. While modern forms of kelp only generally provide enough buoyancy to keep themselves floating, what if they were selectively cultivated? Underwater kelp beds could grow rooted into balls of composted organic matter, bobbing along under the surface of the waves. Long strands of tough kelp with large, buoyant nodules could be woven together into a floating base for a raft, with the leafy ends sticking out around the sides of the raft to gather sunlight and continue growing. [Sargassum](http://en.wikipedia.org/wiki/Sargassum) is one example of a seaweed that floats and could be cultivated for this reason. [Bullwhip kelp](http://en.wikipedia.org/wiki/Nereocystis) is another. Kelp rafts might also offer additional safety against large waves. Kelp is strong, but flexible, so a raft could bend and undulate with the waves without breaking. Raft dwellers could tie themselves and all of their belongings into the raft and ride out a storm. Kelp grows incredibly fast, and is also nutritious. It's possible that the entire lives of the ark-dwellers could shift to be centered on the cultivation of huge floating beds of kelp. Over time, the kelp could even become the focal point of the descendants of the original ark-dwellers. Kelp-based burials would help return nutrients to the kelp, as well. "From the kelp we are made, and to the kelp we shall return..." [Answer] **First off, lets talk about capacity.** The largest modern cruisers, like the [Allure of the Seas](http://en.wikipedia.org/wiki/MS_Allure_of_the_Seas) have a regular capacity of slightly over 5.000 people. Well, an arc is build for an emergency, so let's say it *could* provide room for 20.000 people (People are packed in). But this ignores the fact, that our arc must contain a lot of stuff which a cruiser does not (production likes, recycling facillities, ...) **Supply** Cruiser doesn't contain production lines. They just store the Stuff they need, refill in harbours what is missing. Storing food for 100.000 people for 300yrs is just impossible, we don't need to talk about that. But if the arc is planned for 2-3 yrs, the best way I guess is to build some additional ships as storage, each one smaller than the arc, so if one get's lost not all food is gone. Still, 100.000people for 2-3yrs is overly much. It could help, if the ships are cruising near arctic or antarctic-zone, so it's cold enaugh that there must not be any afford to keep stuff fresh over years. Also, there are whales which are a good source for food. Also, of course, you need livestock. **Long Term survival** It's obvious, that the supplies cannot hold for decades, even if rationed strictly. There must be solutions for the question of how doesn't get food if supply is lost. If the people think they're the last of menkind, they must ensure our persist. They could test everyones health and give the healthiest a priority. This could end in riots, be aware. Who is allowed to have children? This should be strictly regulated. The biggest long-term problem is population! Keep it small. After 300yrs, there might be 10.000 People left, which sounds like a way better number for this size of ship, due there's a lot of more room for cattle. The birthregulation will multiplie the ration priority and well also end in riots. Make sure that the savety personal belief in you. This is a longterm emergency, it will be hard for everyone,... propaganda must be brought to it's limit. **History Check** 100.000 people are hardly possible around 1700 a.D. The first crusier was set up in 1840 by the Peninsular & Oriental Steam Navigation Company, so your engineers who build the arc had really no experience building a megaship for thousands of people, like they have today. **My Opinion** So you got a solution on how to build the arc, setting up a economy (Which is hardly possible to keep the population alive). The problems I talked about had lead to class formation and riots, but the ship keeps going. 300yrs after the journey started, the ship should be in a very very bad condition. Fire, illness, lack of supplies and riots have killed many of the people and maybe many rooms are empty. Maybe the leaders have brought good leading quality and the people now are the descendants of the healthiest and most intelligent people of the starting population. This would be a light in this darkness. The low population at this point would mean, that many gears are unused and there should be more spare parts. I really like the idea, only scrutched its hull and hope to give you some points you did not thought about. [Answer] The biggest design flaws are at the top and bottom. **Top** The very top would not be for living. By making sunlight a valuable commodity, there's no way the tip top would be used to house people. It would be reserved for plants. The problem of soil production would be a big deal. Human and animal waste could be used to help out with this, but it would be far too valuable not to use for farm production. **Bottom** People would have to be able to get to the bottom of the ship to shore up leaks. You can have monsters mid-deck or pretty low, but I would say that there have to be passages that get you directly to the bottom/waterline for problems like this, and it needs to be fairly free of monsters. (Not completely, I mean that's what heroes are for!) **Water** Desalination does not have to be a high-tech process. See [this link](http://water.usgs.gov/edu/drinkseawater.html). **Lost Tech** I don't know that it's possible to design and keep this in working order without better tech than medieval or a bit beyond the industrial revolution. So the idea of a cult of sacred engineers who look after the ship (as suggested by another answer), while nearly everything else is at the medieval level, seems like a good idea. **Ship as an island** This is going to be tough to maintain. Could you make it stationary, as others have suggested? More like an island that used to be a ship? In this case, the ship was a ship to begin with, but it was placed somewhere shallow, and then sand was built up along the sides. If there's nowhere to go (no dry land or other ships) and things are dangerous, on the seas, it might be a good idea to bury it in the sand. In this case, the lowest levels then can be monster laden, and it might be the mids where they worry about leakage. If it's stationary, you can also do some sea farming, like kelp beds and other things. They could use their waste (animal bones and the like) and their dead to create an artificial reef nearby. There will be folks that swim and there should be suits as well. I'd make one side of the ship nearer to the water, and the other higher off it. The side that floods more often can be the poorer side, so you can have two rubrics for wealth--how high and what side. [Answer] You're not going to be able to keep something that big afloat that long. Especially if you can't get to the bottom of the ship to pump out bilge water, or do repairs. Concrete might be the best bet. Getting steel out of the industrial revolution is... quite another. It was the age of iron (and wrought iron) for a reason. Big castings of high-quality steel? 20th century baby. Power: No solar cells (or you're pretty close to lasers) - which degrade after 50 years anyways. No nukes (if you've got them, you've pretty much got computerized controls). You're down to wind action. And you're not going to be doing any sailing of anything that large, or that bulky/tubby. Which means you're going to be helpless in storms. Anything on the surface/top is prone to being washed away/lightning struck. Maybe not so good for the rich. Oh, that's where you were going to put your sails. On masts? Oh, SNAP. Where're you getting replacement sailcoth? Masts? Rigging? From *plants*? Grown *where*? That weren't washed away? Under the deck... how're they getting light? Under glass (crash!). From the quartz lamps... powered how? Replacement bulbs are harvested from the... quartz-fish? Smelted with a furnace powered by... burnable water / or the trees you were planning to use for masts? Trees are sails in and of themselves, better have a ship tall enough to shield them from the wind... and for their roots to grow down into soil... Well, that certainly makes a tall/deep ship - hope you don't run aground and spring a leak. You're pretty much going to need magic, or a whole lot of handwaving - to make it fit your requirements. You're also going to need to have a justification of why the people haven't engaged in all-out war to clean up the lower decks piece by piece. You don't let monsters live in your garden/backyard. --- Big waves: 100ft tall waves have been detected with satellites. 80' wave documented in photo: <http://www.monsterwaves.net/e/monsterwaves.html> Getting hit sideways with a wave == a problem. Rolling your boat is going to be a problem. Just like being that large means you may snap it on the trough of a big enough waves, if you use it long-enough - especially given materials you're likely to be using. Also, not a good idea for traveling north or south with your boat. Icebergs, getting top-loaded with ice, and roaring 40s - for example. The cold seas are only productive because of ocean conveyor belt system - which only exists because continents of land block ocean distribution. ie: No land, no high-productivity areas. > > For lightning strikes you can build lightning rods, I don't see the problem > > > Which are made of metal. Metal and the sea environment don't mesh well. Especially if you have two metals in contact: it makes a battery and you get even more corrosion. Where are you getting your metal from (each new mast is going to need it)? How're you going to maintain it, when you can't get all the way down to hull? If it's not connected to every major mass (Faraday cage), then you're inviting a lighting strike on that area (ie: lower decks). Also, who's training your electrical engineers? Gold may not corrode (and the battery/acid effects will not be strong enough to dissolve it (needs Aqua Regalia), but it'll definitely melt (lightning?, definitely fire) and... get stolen by any unwatched crew (there are no other gold mines on the ship...) This page doesn't say that these boats were protected: <http://www.boatus.com/seaworthy/swlightning.asp> But does dovetail with what I've learnt about lightning... a lightning rod is better than nothing, but is not 100% protection. --- Let's get crazy. Is it *that* important that the whole thing have been engineered? How about bio-engineered? A huge sea-turtle, or whale (without all the diving (hard to keep oxygen for just a whale, much less a whole community running) might work. Assuming enough plankton coming to the animal (human hunting symbionts help keep away competition from out-competing it for food, if animal wasn't engineered). Sea turtles (and land turtles) *have* lived for hundreds of years. Mythologically: Aspidochelone [Answer] An ark that big would be essentially a floating island as such a good model for most of your questions would be [Easter Island](http://en.wikipedia.org/wiki/Easter_Island). You'll note that Easter Island apparently suffered an ecological catastrophe and has a population of around five thousand. Ten thousand might have been possible before ecological issues and with some industrial technology. Area is about 150 square kilometers. So the ark would be maybe 15-by-10 kilometers, also known as huge. Reduction in size can be achieved with technology, but if people had time to built a huge ark they'd probably want to future proof it by making it "dark age" resistant. They'd also build several arks. Basic technology would probably be concrete. Romans knew how to make sea concrete and concrete can be used to build ships. The ridiculous size would probably require significant reinforcement. Easiest solution would probably be the same as we use in the real world: steel. (Although that assumes the demand would result in improved manufacturing, wrought iron would be "good enough".) It should be pretty obvious that a good corrosion protection is needed, but as you could concentrate the reinforcement into core and above sea level parts isolated from sea water and with decent protection from rain water, this should be doable with industrial age technology. I think this would actually scale to 15-by-10 kilometers required for reasonably survivable ecosystem, although with that size you could probably also make it several kilometers deep so it lies on the sea bottom and can't sink. And doesn't need bilge pumps, which is the one technology requirement a floating ark needs. Although you could probably make the bilge pumps operate with hydro power (rain water coming down makes water come up) for a reasonably maintenance free operation. For reducing the required size with technology there is pretty much ONE resource available to harvest: the sea. I think the simplest "built-in" way to harvest resources from the sea would be to build huge pumps that suck in water through nets to harvest debris and fish and maybe even filters to harvest algae. With good enough filters you could harvest plankton in a manner similar to whales. The pumps would also give the island a propulsion system so the islanders could choose where they go. The power source would likely be steam engines powered with either plankton derived fuel or fast growing plants grown for that purpose. The sea harvested biomass would make the island ecology capable of sustaining a higher population or more practically make a smaller ark capable of supporting the desired population. There would be usable wind power to supplement the steam engines, which would reduce the fuel requirements. I think there would be a guild (or cult) of engineers to perform maintenance on the engines. The costs would be paid with harvested sea resources. There would also be a related guild of navigators to map where the ark should go to harvest optimal resources, avoid bad weather, and not collide with sea mounts. These guilds would probably be ark-wide. There might also be a separate guild for resource management that would enforce responsible practices. This would include population control. In agriculture, the staples would probably the cereals and potato much as they are here and for the same reason, high productivity. This would be supplemented with fruits for diversity. The orchards would be placed for erosion control. Medicinal herbs and spices would also be grown. Animals would probably be sparse. Bees would have been included for honey. Meat would have been replaced almost entirely by fish. There would be some horses for farm labor and transport. There would also inevitably be some birds, both sea birds living in the only dry land they could find and poultry. Cats and dogs might also exist for pest control. Otherwise, historical island cultures were tribal with the island divided between powerful chieftains. But I suspect this is in large part caused by islands usually having a mountanous geography that divides them into several isolated parts. The ark would be quite different. There might be some "ridges" for "cave dwellings" and wind power placement and some "points" for the navigators to have wider view, but mostly the ark would be flat without major obstructions. It would probably even have high quality roads and canals built-in. I think this would result in a single government. I am quessing an oligarchy or democracy similar to the Greek models. Conflicts would be between social classes not geographical divisions. [Answer] Well Aircraft carriers generally have about 5000 people living on board, and can be provisioned for about 6 months. They also have hanger decks filled with planes and the hold has enough diesel fuel to supply it's supporting fleet. So something 2-3 times this size could conceivably be enough for 10,000. With some modifications. The Aircraft carrier has fresh water generators to produce fresh water from the ocean, but it is somewhat limited in volume. So having fresh water collection from rain is a good idea. As well as the solar power you mentioned. I would combine them, design the solar panels to be able to catch and funnel water into cisterns. As far as food generation one of the better ones might be dragging a a floating mat of seaweed for 'food'. it could be a mile or so in diameter, it would also explain part of the 'slow' movement of the arc around the globe. It would also help encourage fish and such to be easier to catch by having the 'reef' for them to hide in and around. The 'waste' from the ship could be used to help fertilize the patch. I would think only the 'rich' would be able to have actual gardens to grow veggies in, middle class might have a pot. But there might be some public gardens like museums open to the public. EDT: After rereading the question, IMO, Industrial Revolution technology would not be sufficient to build a ship or island to support 10,000 for a decade, much less 300+ years. I think even today we would be very hard pressed to do such a thing. [Answer] No one would really plan for 300 years, so it seems you would have two parts to what would be a huge floating island. And first, one would have to consider how such a huge thing would avoid ending up anchoring on the seabed somewhere. I think you would end up with ancient sections that may have a core of metal that was gradually replaced by stone or calcifications, concrete, etc. These may be very tall and very deep, with the bottom floors, long sunk and abandoned, resting on the ocean floor. These sections would be coveted and fought over, held by the rich/powerful. There could be many of these, some close together, some further apart. Maybe even some legendary ones held by either monsters or lands of paradise. Some "cities" could have maintained different technologies than others, resulting in competition, trade, spying. Surrounding these would be floating islands made up of organic debris, mats of seaweed, built up soil, citrus trees, etc. they would be kept afloat with a constant effort of building back up what had rotten away. The people on these could be very different from the people in the "cities" with different culture, religion, etc. They would be mobile and drift from place tp place. This could be a good thing, helping with trade and exchange of goods, or a bad thing to be avoided at all costs - becoming "lost" to the "civilized" world. Islands lost this way could be found later reverted to various levels of savagery. Lower levels could be used as "dungeons" if they had surviving tech to pressurize and pump air into lower, previously abandoned areas. This could be done for living space, to retrieve artifacts, etc. You could also have surviving scuba tech and/or gill breathing mutants. You could get some of the same ideas by coming across long lost floating islands. Add some radiation by giving some cities, now long abandoned by rational men, decayed nuclear reactors, and you would have a source of mutants and monsters. [Answer] **Monsters are the key.** This isn't a true answer, merely a thought, so perhaps this should be a comment, if so, I apologize. But it looks like some of your unsolvable problems can be addressed with the monsters themselves, specifically the sustenance and ark sustainability issues. 1. Sustainability: Without repairs, your ark is not going to last 300 years. So, who's repairing it? Simple, the monsters are. Either specialized species like ants, bees, or any other building creature instinctively shoring up leaks, or intelligent monsters making repairs because that's what any intelligent being would do. (As to what materials the monsters are using, that's up to you. I'd personally prefer biologically produced substances, but that might be a little too high fantasy for your tastes). 2. Sustenance: No matter what general solution you have for food and water on the ark, there's probably going to be a food shortage. As a result of this, your population is probably going to end up eating the monsters (unless they're completely toxic). This can actually play to your advantage. It gives your adventurers an additional to venture down into the depths, and it also explains the lack of crusades/exterminations. After all, it doesn't make a lot of sense to exterminate a food supply. [Answer] Such a big ship floating for centuries without repair in dry dock would have plenty of problems: * [barnacles](http://en.wikipedia.org/wiki/Barnacle) - especially around propulsion and steering. Effectivity of propulsion and ability to steer will degrade significantly. * total inability to repair water-displacing part of the structure, or to obtain materials to repair broken machinery. * Fuel. Even nuclear fuel needs to be replenished. Solar panels produce some 10-15 watt per sq foot. Less in areas closer to poles - where sea life is more abundant. So you can have either energy or food, but not both. * Providing food. You need to live off the sea, with sunlight providing energy to you (and not plants). To help you a bit, you can feed scraps and bycatch to insects (which need no sunlight) and feed insects to chickens, getting some non-fish meat. Also fungi can grow without sunlight. * Metal is non-renewable resource. What wears off or rusts away, is gone forever. * Adverse weather. You are one [rogue wave](http://en.wikipedia.org/wiki/Rogue_wave) away from complete disaster. IMHO in such no-dry-land world, you would be better off to build some non-floating structures on shallow reef areas, preferably using [biorock](http://en.wikipedia.org/wiki/Biorock). Such areas are incredibly biologically productive (lots of food), you can build wind turbines for energy (leaving land for agriculture), you have no problem with navigation, and you can drag your fishing boat to dry dock to repair them. Possibly you can even mine metals from sea bottom. And make boats from plastic. Biggest reef [Saya de Malha Bank](http://en.wikipedia.org/wiki/Saya_de_Malha_Bank) - 40K km2 could support 100K people easily. [Answer] **The Entagled flotilla** Maybe a fleet aproch would work for your setting, where there are big ships where people live, but others that only provide support. A flotilla of vessels that are interdependent, much like Battlestar Galactica settings, seems more plausible. This allow to have some specialized ships to specific functions (livestock, farming, water collecting, etc), creating a more versatile community. Some of the most obvious requisites for an atonomous system is redundancy and resilience. You can still have a very large ships for people to live in, but instead of visiting the lower decks to explore, you can go to the further ships of the flotilla, perhaps connected with ropes or other systems, and long ago considered lost or forbidden. ]
[Question] [ I don't just mean tides or large-scale floods and droughts but a premise where one or more large bodies of water (or even every such body if that makes it easier) disappear, only to reappear one or two millenia later. My intuition tells me this would logically happen either through a form of cyclical geological porousness that leads water to sink under the planet's surface or some kind of evaporation mechanic, but that assumes the water has to go somewhere. Perhaps large volcanoes that then act as sinkholes? Wormholes that suck out the water? Saturnine water rings? [Answer] ## Ice ages combined with a Mediterranean type basin Your planet has the following features: * a more extreme climate than Earth, perhaps because it has very high [obliquity](https://en.wikipedia.org/wiki/Axial_tilt) or perhaps because it is an [eyeball planet](https://en.wikipedia.org/wiki/Eyeball_planet). Because of this it has very large ice sheets at the poles (or dark side) and a region at the equator (or sunlit side) that's so hot that ocean water readily evaporates, leaving salty desert or a body of salty water like the Dead Sea only much bigger. It might have less water than Earth, to facilitate these features. * a strong seasonal cycle that lasts several thousand years. (I'm unsure of the orbital mechanics needed to achieve that; it could be worth an extra question if there isn't one already.) * a particular quirk of topography, described below. Your civilisation lives in and around a basin in the temperate zone, somewhat similar to the Mediterranean basin on Earth. The basin has an opening where the water can flow out into the hot region. But this opening is far to the North (or South or towards the dark side, wherever it's cold), so the water has to flow North and then turn around and flow South again, until it eventually reaches the hot region. The basin floor slopes downward slightly towards the North, and the opening is deep enough that the entire basin can drain out through it. But because of the seasonal cycles, this opening is blocked with ice most of the time. As the planet slowly starts to get warmer, the ice sheets start to melt, and this fills up the basin. (So this will be a freshwater ocean.) In the hottest years of the cycle, so much ice melts that the opening strait becomes unblocked, and at that point the entire basin suddenly drains. Once that has happened the water will flow to the hot region and start to evaporate. The evaporation explains why the water can flow downhill instead of just meeting another ocean. The evaporated water will ultimately fall as snow on the ice sheets, replenishing them. After this, the basin will remain dry for most of the thousands-of-years cycle, until the planet has cooled and heated up again and the melting ice refills the basin. If desirable, the cycle could be shorter, say around 100 years or so, but the ice doesn't usually melt enough to drain the basin. This means that the oceans will fill up much quicker, since the ice will be melting again only 100 years after the draining, but it also means the draining will be much less predictable. A hundred year cycle could be achieved by having your planet orbit a brighter star than our Sun, at a larger distance. [Answer] Bridge of the gods landslides. the bridge of the gods geologic formation in Oregon was a series of land slides that crossed the columbia river damming it for years, a lake would build up behind it. The dam created a natural bridge. that lake would eventually breach the natural dam again cutting off the the ability to travel. The lake was hundreds of feet deep, so a serious barrier. This even got incorporated into the local mythology. But best for your story this happened over and over again, several times in human history. the last one around 600 years ago. Because of the local geology these huge landslides are common. <https://www.youtube.com/watch?app=desktop&v=Y-w65F_b91U> [Answer] Oceans are interconnected, and form an equipotential surface for the planet's gravity field plus centripetal force, in order for the entire ocean to recede it's required to somehow move a part of the planet against gravity (up or down), *then* back. This takes too much energy to even bother with a realistic explanation. However, there is one force that's strong enough to perform this: **Incomplete black hole tidal locking** If there is a black hole somewhere nearby your planet, and your planet being decently close to a black hole to experience tidal disruption of several kilometers, while also being not totally tidally locked to face one side towards it, then your oceans might be able to recede then get back with a period of half a day. So you make the day last several millennia, relative to the black hole, while the warmth and light would come from another star located elsewhere (at a distance far greater than the planet's, making this binary system a separated one). Carefully selecting orbital parameters could net you a planet close enough to a black hole to have tides of several kilometers, lasting millennia because of leftover rotation relative to the black hole, yet day and night lasting about normal because of the distant star that's heating the planet from afar. [Answer] You could appeal to oscillations in the orbital eccentricity of your planet, due to gravitational perturbations from a giant planet or binary star. This could cause an extreme version of Earth's Milankovitch cycles. See here for more details on extreme Milankovitch cycles: <https://planetplanet.net/2014/10/08/real-life-sci-fi-worlds-3-the-oscillating-earth/> See here for more on Earth's orbital oscillations and "standard" Milankovitch cycles: <https://planetplanet.net/2022/08/22/billion-year-evolution-of-the-solar-system-climate-forcing-and-orbital-chaos/> [Answer] Ice ages are an example of this. Just with solid water instead of liquid water. Over the last couple million years, huge bodies of solid water formed in North America and Eurasia, dissipated, and reformed dozens of times. [Answer] Have a bit more tectonically active planet. Take a body of water such as the Gulf of Mexico or the Mediterranean and have the crust rise and fall. A more active crust can raise or sink large chunks of the crust. For a small example, see how the Campi Flegrei caldera is rising and sinking over hundreds of years. There are two ways to remove an ocean. One is to block off the water inlet such as the Strait of Gibraltar and it dries up. The other is to raise the land under the ocean so that it recedes hundreds of miles. For example, much of North America west of the Appalachian Mountains was under sea level for a long time. The evidence is both the limestone layers and the beach front sandstone layers. It is only recently (geologically speaking) that it became high mountains. The mantle under North America has pushed it up. By having a more active planet, these changes can happen far faster than on Earth. [Answer] To make it possible through a geological cycle, you may use [astronomical nutation](https://en.wikipedia.org/wiki/Astronomical_nutation). This is a change of the planet's axial tilt over a millenia. The axial tilt may change its orientation relative to the sun. On Earth we have polar ice caps right at the poles. The accumulation of polar ice caps can change the sea level only if the body of ice is located on land. Ice forming as it floats on the water will not change the water level until it is large enough to touch the sea floor. Put an ice cube in a cup of water and watch the cube melt. You will notice that the water level does not change. Ice forming on land (like on Antarctica) takes water from the ocean and the ocean level will go down. As the ice cap over the continent melts and water flows into the sea, the ocean level rises. As the axial tilt changes, North and South poles can either be over a deep ocean or a continent. If the antipodal points (North and South) are both the same (either land or sea) then the cycle variation is amplified. If the antipodes are opposite (one land and one sea) the effects mostly cancel each other and the cycle variation is small. [Answer] If the core of your planet had cooled, there would no longer be a mechanism for creating mountains and valleys. Over the millennia, the taller parts would be worn down and the deeper parts would be filled in. Mars, for instance, would currently only have oceans about 300 meters deep. At that point, it would be fairly easy to have a cycle of ice ages that dry out a basin and refill it. That, however, happens over a period of 10k years, which might be a bit long for your concept of "history." [Answer] ## Lake Megachad Quoting from [Wikipedia](https://en.wikipedia.org/wiki/African_humid_period#Lakes_and_rivers_of_the_Sahara) on conditions about 10,000 years ago: > > This enlarged Lake Chad reached dimensions of 1,000 by 600 kilometres (620 mi × 370 mi) in north–south and east–west direction respectively, covering the Bodélé Depression and perhaps as much as 8% of the present-day Sahara desert. > > > Current day Lake Chad is *significantly* smaller than that. So to reiterate, real-world history supports massive inland seas forming and dissipating on timescales of 10,000 years. [Cyclically](https://en.wikipedia.org/wiki/North_African_climate_cycles). It looks like every ~20,000 years, the Sahara enters a ~6,000 year "wet" period, where monsoon rains basically transform it from desert to savanna. This is likely based on small, cyclical changes in Earth's orbit that change the amount of sunlight hitting the ocean, which impacts monsoon winds. Thus, the major requirement for this cycle to produce large inland seas for your story would be: there's a [endorheic basin](https://en.wikipedia.org/wiki/Endorheic_basin) for the monsoon rains to fill. As long as there is a depression with no outlet, the rains will do the work of creating your inland sea, and then the later heat will remove it. [Answer] A slow moving, massive object almost in orbit (small black hole), creating a massive tide at the poles, freezing the whole water into a huge mount everest sized mountain of ice, then once it departs (or the planet is detached from its orbit around it), the ice slowly melts and the oceans return. [Answer] There is lots of room in the atmosphere to hold all the water. The planet's orbit around the sun is elliptical, just enough to warm up the water into the atmosphere, then cool it back down into the oceans. Or make the planet orbit a binary system (two Suns, one slightly larger), so it still can have normal seasons. ]
[Question] [ Let's pretend these magnificent and beautiful creatures are able to reproduce asexually so we can forget about their mating habits or their partners. I have yet to witness any hard shell eggs laid underwater by any species and most mammals like to bear live offspring even underwater, just like whales and dolphins. Sea turtles prefer to bury their hard shell eggs in the sand on the beach partly because these eggs need certain temperature to develop. Is it possible to have soft shell mermaids egg/spore in the sea/ocean? [Answer] Unless the mermaids you're imagining are significantly more "alien" than the ones in typical mythology, then it doesn't make a lot of sense for them to lay eggs. Mermaids are *supposed* to be half human aquatic beauties - that, to me, implies that they are mammals, and thus bear their offspring until giving birth to a living baby. If, however, you'd like to make them utterly inhuman, then sure, they can lay eggs like fish. They may be limited in ***where*** they can lay them based on the pressure the eggs can withstand, the temperature of the water, etc. They may lay the eggs in caves along the shore which they can then guard, for example. [Answer] **They lay eggs.** This is [explained in Futurama](http://theinfosphere.org/Transcript:The_Deep_South) by Umbriel the mermaid: > > I'm not your first am I? I mean, I-I lay my eggs and leave and you release your fertiliser. > > > (Note that Umbrel is a moon of Uranus. Just like another famous mermaid, Ariel) [![enter image description here](https://i.stack.imgur.com/kbXSS.jpg)](https://i.stack.imgur.com/kbXSS.jpg) As we all know, mermaids have the human half on top and the fish part on the bottom (though some wish it was the other way around). While they may be classified as mammals, not all mammals give birth to live young. The notable example is, of course, the other chimera of the animal kingdom, the mighty [platypus](https://en.wikipedia.org/wiki/Platypus). Eggs don't need a hard shell underwater for the same reason octopuses don't need skeletons, they're supported by the fluid around them and internal hydrostatic pressure. As they're made of essentially incompressible liquids, they can be at any depth (perhaps near volcanic vents for warmth). [Answer] It depends on their tail, the more likely and realistic tail is a dolphin or dugong (manatee) tail instead of a fish tail, in which the mermaid would give birth to live young. The less likely would be the fish (or even reptile) tail. As AndreiROM said, this would probably make the rest of the creature less mammalian and therefore less human, so not a half-human aquatic beauty. In this case they would lay eggs. With only forelimbs and no hind limbs, I'd guess they'd stay underwater and lay soft-shelled eggs. Saying that, if they lay hard-shelled eggs on land it could explain what they're doing on the surface when they're spotted by sailors and fishermen. *Although it's not relevant to the question but instead the context for the question, I want to say just one last thing as a side note.* *How would this species ever survive or even evolve into existence with only asexual reproduction? I suggest that the species comprises of one sex that has a unique sexual system that allows exchanging of genes (a simple one would be that they simply lay eggs and then fertilize each other's eggs. A few will become clones and a few will mix, or they could control the fertilization to remove chances of clones.).* [Answer] If you google for "mermaid purse", you will find pages about [egg cases](https://en.wikipedia.org/wiki/Egg_case_(Chondrichthyes)). They look like this (taken from Wikipedia): ![Mermaid purse](https://i.stack.imgur.com/s5Y6Y.jpg) So when you see that lady casually swimming around the sea, doing her underwater shopping and chatting with her girl friends, and you notice her lady bag - it hasn't got a mirror and makeup in it. That's where she keeps her unborn children. [Answer] In part, you have made an unwarranted assumption - that merfolk reproduce like "higher" animals, with either live birth or large eggs. The life cycle of mers is completely up to you, and there is no reason to think of the young as recognizable, smaller versions of adults. For all you know, mermaids produce hundreds or thousands of small eggs, like frogs or fish. The hatched young go through several life cycles, eventually becoming something like their final form. At some point they would join groups of adults to become socialized and educated. Or not. Like I say, the subject is obscure. [Answer] Fish and Amphibians lay soft gel-style eggs, by the thousand. Reptiles lay hard-shell or leathery eggs. Typically less than a hundred. Mammals have live births, with fewer than 10 offspring. Marsupials do lay eggs, or have pouches. You notice that more advanced species have fewer offspring. Mermaids are intelligent (typically), so they cannot lay thousands of eggs, there will not be enough resources for a proper brain in any of them. Better brain means fewer offspring, which means better protection for each offspring (hard shell or newborn's ability to react to its environmnet) So mermaids will have to have a few offspring, and they will have to be either relatively tough eggs that they guard, or live birth. Eggs do not have to have a hard shell, it can be thick leathery hide. [Answer] Most of the previous answers make much harder assumptions than those actually found in nature. I know of no reproductive process in the animal kingdom that doesn't have an egg or egg-analogue at some point. Also, most of the cited situations (reptiles do this, mammals do that) have more exceptions than the answers imply. While 'most' fish/amphibians/reptiles do lay eggs, many don't. While the platypus lays eggs, most mammals don't. Some fish and reptiles (specifically some shark species and anacondas) hatch their eggs inside the mother, and then 'give birth' to live offspring. I don't see any significant difference (at least as far as this question is concerned) between that process and the process of a mammalian amniotic sack(egg-analogue) breaking, and then the mother 'giving birth'. In the end, there is an 'egg', and it will 'hatch' and the offspring will come out of the mother whether still in the 'egg' or not. So the level of 'fish-like' qualities vs the 'mammal-like' qualities of the merfolk isn't really a factor. Instead, the answer is which fish and/or mammal is the mermaid the most similar too, in terms of reproductive biology. It could be mammalian, and still lay eggs, or fish/shark and still give live birth, or not. Yes, it's entirely plausible for a species of merfolk to have relatively softshelled eggs, if that's how you want them for the story. And it can be adjusted anywhere along the entire range of mammal, amphibian, reptile, or fish spectrum as needed. ]
[Question] [ We all know of plants that draw in animals with sweet nectar or even just sit around hoping an insect will sit on it and get caught, but I'm imagining a forest dimly lit by the flickering flames of a plant that tried to attract moths for consumption. These plants are then harvested by those who dwell in the forest for their fuel. How would a plant produce a small flame (what chemical process would need to occur) and how would it prevent itself from being burned by it? [Answer] **First lets look at another reason that a plant might want to produce fire:** A great many parasitic insects are attracted to CO2 and most organic substances release some amount of CO2 when burned. So producing CO2 may create a small advantage in attracting insects for pollination and/or consumption. **Next how might a plant self ignite:** According to several sources; cotton rags when soaked in linseed oil can [spontaneously combust](http://en.wikipedia.org/wiki/Linseed_oil#Spontaneous_combustion), under the right conditions. > > The oxidation of linseed oil is an exothermic reaction, which > accelerates as the temperature of the rags increases. When heat > accumulation exceeds the rate of heat dissipation into the > environment, the temperature increases and may eventually become hot > enough to make the rags spontaneously combust. - [Wikipedia](http://en.wikipedia.org/wiki/Linseed_oil#Spontaneous_combustion) > > > We could extrapolate on that, and picture a plant that could produce a bulb of fibrous material that it would soak in a oil/resin that had similar oxidizing properties. ta-da... Fire! **Now on to sustaining the fire:** The above mentioned bulb could and probably would burn rather quickly. For a sustained fire we would need the stem to act as a tube to continue to feed the, now burnt, bulb with oil without the stem itself burning away. If the stem was kept sufficiently moist it should hold up for a good long time. (have you ever boiled water in a banana leaf?) So that shouldn't be a huge hurdle. Continuing to feed the bulb with oil should be fairly straight forward as well, the heat from the flame should create enough suction to keep the oil flowing, or you could look for a more wick like solution. After the initial combustion the plant would only really need to continue to produce enough oil to keep a small flame going, I doubt a major reservoir would really be needed. **Now what happens when if the flame goes out?** A simple solution here would be that the oil dries and hardens at the end of the stem forming a clot, this would be the signal to the plant to start producing a new bulb. [Answer] Fire requires a lot of energy, most of which does not make light. [Bioluminescence](https://en.wikipedia.org/wiki/Bioluminescence) is how a plant would produce light. But, you want fire. Ok. Plants already produce oxygen and hydrogen via [photosynthesis](https://en.wikipedia.org/wiki/Photosynthesis). If the plant stores one or both of these gasses it could use them to keep a small flame lit for short periods. A safer source of fuel would probably be a wax or oil produced naturally by the plant. The difficulty is in getting the fuel ignited. This might be done with a lens made from water to focus direct sunlight. Once the flame is going, it could burn into the night and attract moths. By the way, the [reason moths are "attracted" to light sources](http://www.livescience.com/33156-moths-drawn-artificial-lights.html) is a pretty interesting aside. Moths aren't necessarily attracted to lights, their navigation is just getting messed up. Moths are expecting the light they see to be parallel light beams, since they evolved when all they got were parallel rays from the sun or moon. This means if they keep incoming light rays at the same angle, they'll flight in a straight line. Point sources of light like lamps or candles have very divergent light rays. So, moths spiral into a point light source because a spiral on a diverging light source looks like a straight line to a moth. Neat, right? ![enter image description here](https://i.stack.imgur.com/UpcP8.gif) [Answer] [Samuel's answer](https://worldbuilding.stackexchange.com/a/11060/458) shows that moths are only attracted to local lights because their current evolved behavior is relative to a world with a single, distant light source. So, **in a world were plants evolved flame production, it would likely not be to consume bewildered moths** because moths would equally evolve to simply avoid the flames. **There would have to be another selective pressure for this to be convincing.** I may be wrong, but I believe that bioluminescence is almost always a method of communication, so **these plants would be more believable if the flames served a communication purpose that aided survival**. But why would a plant need to communicate? Perhaps the **communicating might be necessary for reproduction**. Many plants have male and female counterparts, rather than having both parts, as most plants to. Sporing plants also have an interesting reproductive cycle. Some odd ones have very, very odd reproductive cycles. In your world, the flame could be some kind of signal that involves other plants in the reproductive cycle. I'm not going to bother with details on how the reproduction might work, because there really is a plethora of real example you could modify. If you toss in a little symbiosis you can get really creative. One species can play off of the other and they both benefit from the flame adaptation. But now the question, **why flame instead of bioluminescence?** We already know bioluminescence can evolve and it is quite effective in aiding survival. Why would flame be any different? The first thing I can think of is that flame fills the air with exhaust. Yes, it makes light too, but perhaps the light in combination with a particular gas that comes from the burning is what triggers the other plants to do their part of the reproductive cycle. With all this in mind, **I envision that the plants grow in close quarters** because the light and the exhaust would thin quickly as more distance was given between individuals. I also envision that **the plants only light once or twice a year**. Making flame is far more consumptive than bioluminescence, so the plants need time to fill a fuel reservoir. And now the final questions: **What is the fuel and what would ignite it?** Ignition is probably best solved with **electric spark**. A simple moving part on the plant can build up static and release a spark at the right moment. An **explosive chemical reaction** might be possible, but at was mentioned in [pmcoltrane's answer](https://worldbuilding.stackexchange.com/a/11066/458) even the bombardier beetle's explosive reaction tops out at under 100C. **The real problem I think is the fuel**. We don't really know of any chemicals that burn in low enough heat so they would not damage the plant, plus most combustion reactions need forced air (or compression) to start up. Maybe a wind channel structure could handle that. **Perhaps your audience would be willing to suspend their disbelief on these points**. I probably would be if the rest of the story was interesting and they way the people used the fuel was a central point in the plot. [Answer] There are plants that evolved to create wildfires to kill the competition. Of course, native to Australia. Adaptations that promote fire include: a high content of volatile oils in the leaves and litter; litter that breaks down extremely slowly; an open canopy; long strands of bark that hang from limbs after peeling and which can be carried alight for many kilometres to start new spot' fires well ahead of the fire front. <http://www.australia.gov.au/about-australia/australian-story/eucalypts> [Answer] There are definitely going to be some hypothetical's in my answer; but here we go. It sounds like your ideal plant is something akin to the venus fly trap, pitcher plant, or even the [carrion flowers](http://en.wikipedia.org/wiki/Carrion_flower) (which attract insects for pollination as opposed to food) in terms of behavior; however rather then sweet or rotten smells you want fire to be the primary attractant. **Surviving Fire** Lets start with a plants ability to survive fires. Natural fires are typical of various conditions like lightning and dry plant matter ([Fire Ecology](http://en.wikipedia.org/wiki/Fire_ecology) for more on the subject of natural areas with fires). Plants survive these conditions in a number of ways, Ponderosa Pine trees lose lower branches and have tough trunks, thus they keep their living branches and leaves (needles) above the reach of fire. Although if you're aiming for a smaller plant then your particular plant will be one that stores energy in the roots and regrows out of the ground following a fire. So that's an overview of how nature does it now. What about some ways it could handle it? For one you could have the cellulose of your plant pull silicate and other minerals out of the ground and embed them in the bark creating a stone-like layer to protect from flame on the outside of your plant. The leaves could also produce a flame resistant oil/coating that protects from heat and open flame. [Fire-retardant gel](http://en.wikipedia.org/wiki/Fire-retardant_gel) absorbs large amounts of water to form a protective blanket. **Making fire** So now we need to make a fire. The main way I see this working is having your flower be a swamp denizen. The large amount of rotting materials combined with a symbiotic relationship to certain bacteria could allow your plant to create and store methane gas for burning. But what about the heat? Well nature even has you covered here; [Thermogenic Plants](http://en.wikipedia.org/wiki/Thermogenic_plants) create excess heat; although you'd have to scale this up I would say that it's at least possible. So your plant could have a stalk that releases a stream of methane and is lit by thermogenic action. It could operate on photosynthesis during the day and come nightfall the fire could start. [Answer] My immediate thought was something like a [pitcher plant](http://en.wikipedia.org/wiki/Pitcher_plant), which is already carnivorous, and lures its prey with nectar before trapping it in a pitfall. What if the plant were something like a pitcher plant, but secreted liquid wax into its pitcher, like a natural candle? A specialized leaf, stem, or flower parts could evolve to be naturally porous, to become a sacrificial wick when dried out. Once ignited, it would lure moths and other insects, which would fall into the liquid wax. The wick would burn until all the wax was consumed, at which point the flame needs to die before burning the plant. (The plant may have a high water content, or line itself with a nonflammable buffer.) That leaves the problem of ignition: the [bombardier beetle's](http://en.wikipedia.org/wiki/Bombardier_beetle) chemical reaction doesn't even reach 100°C. [This list of hypergolic](http://en.wikipedia.org/wiki/Hypergolic_propellant) reactants looks pretty toxic. Maybe the wick naturally produces something like nitrocellulose, and ignites with a brief spark once the wick dries out sufficiently? Plenty of animals harness electricity: I'm not sure about plants. [Answer] Alcohol and acid can be combined to produce fire (though the alcohol should be of a certain concentration and the acid should be of a certain nature -- details, details...). There are several instances of fruit naturally fermenting in nature, instances of plants with reservoir systems, and instances of naturally occurring acidic compounds of the correct nature (though mostly in animals, not plants). It is plausible that a plant could maintain a reservoir-segment base that catches whatever seeded fruit is not eaten outright (or even more interestingly, a plant that has a reservoir catch and lives symbiotically with another, taller plant that produces the fruit and drops it, some entering the reservoir). This reservoir would be a good place to ferment without disturbance, and either the shape of it could encourage evaporative distillation or some sort of root-like leeching mechanism could grow as a mesh through the fruit to cause alcohol to be drawn to a secondary reservoir or leaf-like blivet due to viscosity differential or whatever. The same plant, if it produced an acid of the right form could combine these two to create fire. The real issue is, why would the plant do this? While the complexity of the relationship and mechanics of a symbiotic plant system like a fruit-tree/acid-making flame thrower are actually *not* that far out considering how many intensely complex (and at first glance downright unlikely!) symbiotic systems exist in real life, the odds that this would be a beneficial capability for a plant that *lacks the cognitive ability to decide when to shoot fire* are pretty long. If you can resolve the issue of how the plant decides when to do this (unless you just invent intelligent plant life in your world, then the problem is solved, but you have a new problem of making plant-monsters acceptable to the audience without going completely campy 1950's sci-fi style) then you have a sound basis for a fire-breathing or flame-throwing plant system in the form of a fruit-to-alcohol and acid-excretion system that combines wherever the fire is supposed to happen. The moth thing is not, I believe, sufficient basis for this -- you need something else. Something like self-destructive perimeter defense which is individually sacrificial but overwhelmingly effective for the greater system, perhaps (similar to how war fever has beneficial group survival outcomes for humans and many other mammals). [Answer] Plants can & do produce highly flammable substances. Consider the gas plant: <https://en.wikipedia.org/wiki/Dictamnus> Or have you ever squeezed an orange peel into a candle flame? So the problems are 1) an ignition mechanism; and 2) an evolutionary reason/pathway for spitting flame. [Answer] The plant could hang a small sphere of dried sugar above a wick of fibrous material, which would be partially submerged inside a constantly replenishing supply of oil. The wick would double as an extremely efficient nutrient absorber, and the moth would fly into the flame, burn up, and have its remains absorbed. ]
[Question] [ Suppose a message was sent to the past with a diagram, description, and use, of the simplest fission weapon. It didn't describe how to mine Uranium, enrich it, or even a description of WHY it works or atomic theory, but did indicate "U235 (and indicate element 92) needed to be separated and concentrated from U238". If the USA or another superpower got the message, took it seriously, and wanted to build it, how early could humans have achieved this? Given that explosives, mining, atomic theory, and industry was pretty well along in 1900, I'd think 1900 or earlier. I suspect a sufficiently large enrichment plant would be the tricky part. [Answer] # Probably Not Much Earlier Than We Did The problem is less with the concept of a nuclear bomb - Enrico Fermi famously speculated as to the liberation of atomic energy for destructive purposes in the early 20s - and much, much more with the necessary materials science required to make the fissile material. It took thousands of centrifuges, billions of dollars, the [accidental discovery of Teflon](https://www.sciencehistory.org/historical-profile/roy-j-plunkett)... The "billions of dollars" part is also a big deal. It was \$2B to get to the first bomb's worth of material, in 1942 dollars. That would only have been $1.2B in 1900, assuming that individual tasks wouldn't cost more in real values (which it would), but that would have been 10% of the entire GNP of the time. It's hard to imagine, barring an existential threat (which WWI was not!) a country spending an amount of money nearly impossible to contemplate on something that atomic theory didn't yet support. You'd also need advances in mining. Chemical leaching in place of traditional smelting. By the time the US felt it *needed* an atomic bomb, it already had plenty of scientists who postulated that it was possible... and had all the other tools it needed, as long as it had the motivation to spend an enormous sum of money. In 1900, it didn't have the technology, nor any of the other tools. Knowing that it was possible wouldn't magically advance those - particularly lacking the motivation. *Addendum*: Per @AlexP's comment, the centrifuges weren't even successful, though they would be eventually. But I should also point out that prior to WWII, there wasn't really a country on earth that would be called a "superpower". Prior to WWI, the United States barely had an army! ]
[Question] [ Planets that are larger and have higher gravity tend to have thicker atmospheres, since it is easier to hold onto gases. Higher air pressure leads to a higher air density, and therefore, a greater the air resistance. So, on a planet twice the mass of Earth with a proportionally thickened atmosphere, would a leaf fall faster or slower? [Answer] As I mentioned in a comment, I am making the following assumptions about this planet: 1. Twice the mass of Earth; $M = 2 M\_e$ 2. The same bulk density as Earth; $\rho = \rho\_e$ 3. The same atmospheric composition as Earth; 4. The same surface temperature as Earth; $T = T\_e$ 5. An air column proportional to surface gravity; i.e. the total mass of air above any square meter of surface on the planet is greater than on Earth by the same proportion as surface gravity; $\sigma\_{air} = \sigma\_e \frac{g}{g\_e}$. With the previous assumptions, this ends up meaning that the total mass of the atmosphere is double that of Earth. # Planetary radius The mass of a sphere is its volume times its density: $$M = V\*\rho$$ The volume is given by: $$V = \frac{4}{3} \pi R^3$$ By setting the mass equal to double the mass of Earth, we can find the radius: $$ \frac{4}{3} \pi R^3\rho\_e = 2 \frac{4}{3} \pi R\_e^3\rho\_e$$ $$ R^3 = 2 R\_e^3 $$ $$ R = \sqrt[3]{2} R\_e $$ # Surface gravity Surface gravity is calculated from the formula: $$ g = G \frac{M}{R^2} $$ Substituting from above, $$ g = G \frac{2 M\_e}{(\sqrt[3]{2} R\_e)^2} $$ $$ = \sqrt[3]{2} G \frac{M\_e}{R\_e^2} $$ $$ = \sqrt[3]{2} g\_e $$ # Air pressure and density We decided that the mass of the air column was proportional to surface gravity: $$ \sigma\_{air} = \sigma\_e \frac{g}{g\_e} = \sqrt[3]{2} \sigma\_e $$ Air pressure is the mass of the air column times the acceleration due to gravity (for a thin shell of atmosphere like Earth's, we can assume that the acceleration due to gravity is constant in the atmosphere without much error). $$ P = g \sigma = \sqrt[3]{2} g\_e \sqrt[3]{2} \sigma\_e = \sqrt[3]{4} P\_e $$ From the ideal gas law, we know that density is proportional to pressure at constant temperature (and composition): $$ \rho\_{air} = \sqrt[3]{4} \rho\_{air,e} $$ # Terminal velocity of a leaf The density of a leaf is much higher than air, so I will ignore buoyancy effects. I'll also assume a drag coefficient of 1, which strikes me as reasonable for a leaf. The velocity of the falling leaf is when the drag force due to air resistance balances the force of gravity: $$\frac{1}{2}\rho\_{air} v^2 A\_{leaf} = m\_{leaf} g $$ Assume the leaf has some thickness $d$ and density $\rho\_{leaf}$ which are the same on both planets. Then: $$\frac{1}{2}\rho\_{air} v^2 A\_{leaf} = A\_{leaf}d\rho\_{leaf} g $$ $$ v^2 = 2 d \frac{\rho\_{leaf}}{\rho\_{air}} g $$ $$ = 2 d \frac{\rho\_{leaf}}{\sqrt[3]{4} \rho\_{air,e}} \sqrt[3]{2} g\_e $$ $$ = \frac{1}{\sqrt[3]{2}} v\_e^2 $$ $$ v = \frac{1}{\sqrt[6]{2}} v\_e $$ $$ \approx 0.89 v\_e $$ # Different assumptions If we make the atmospheric increase larger, which I think is more realistic, then the leaf will fall even slower. If we increase the surface temperature or the proportion of light gases (Helium, Neon), which are also realistic, then the air density will be less and the leaf would fall faster. Making the planet denser (rock is not very compressible, so this would probably mean more Iron relative to Silicon) would increase the surface gravity, but since the atmospheric increase was proportional to surface gravity, this still makes the leaf fall slower. It is worth noting that maintaining Earth's surface temperature in a thicker atmosphere implies that the planet orbits farther from its star or has a dimmer star. **tldr;** For these assumptions, the leaf will fall slower on a larger planet. # Edit: Buoyant force The question has been edited to specifically ask about the buoyant force, so here's a little more info on that: The buoyant force is given by the displacement of air by the leaf. The density of a fresh leaf, like other living tissues, is close to that of water, about $1000 kg/m^3$. The density of air at standard temperature and pressure is about $1.2 kg/m^3$. So the buoyant force is roungly $0.1\%$ of the force of gravity. If we double the mass of the planet and its atmosphere, then the density of the air increases to $\sqrt[3]{4} \times 1.2 kg/m^3$, or $1.9 kg/m^3$, so the buoyant force increases to almost $0.2\%$ of the force of gravity. This is still too small to an effect to bother including in the calculation. The fact that a leaf falls slower in air than in a vacuum is almost entirely due to drag (aka air resistance), not buoyancy. You can test this by crumpling a leaf into a ball. It has the same buoyant force it always did, but much reduced drag, and it falls much more quickly. [Answer] Gravity is not the only thing to consider for atmospheric density; pressure (and by extension density but they are different properties) can also be increased by the amount of energy (read as heat) being stored in the atmosphere. Also, the relative strength of a magnetic field ( terrestrial or induced) can have an impact on how much of the atmosphere is retained as well. This is best exemplified by Venus, with a very similar size and mass to earth but much denser atmosphere. There, bouyancy is your friend as it is going to be higher than on Earth but only needs to counteract the same gravitational force. Of course, building a bouyant airship that can survive that atmosphere without dramatically increasing weight is going to be a challenge, meaning that we're not comparing similar circumstances. Finally, the other consideration is planetary density. Gravitational force increases proportionally to the square of your proximity to the center of mass, so a planet with the same mass as earth but (say) half the diameter is going to put you further down the gravity well yet may only have a similar atmospheric density. That would make the bouyancy have to work harder against gravity than on a planet with earth like density. In short, there are a lot of factors to consider, gravity and atmospheric density being only two. All other things being equal however, I'd argue that if planetary density is equal, atmospheric density is proportional, etc. then the real deciding factor is whether the distance from the center of the planet is increasing at the square root of the increase in mass. If it's increasing at a lower rate, bouyancy will have a greater effect. If it's increasing at a higher rate, bouyancy will have less of an effect. But, it should be noted that this is a highly simplified way of looking at it and you would need a lot more specifics to figure it out on a case by case basis. [Answer] The question specifies "proportional". If we assume twice the gravity and air density, then: The answer is no. Terminal velocity would be neither faster, nor slower. Note, the leaf would accelerate faster initially. But it would reach terminal velocity quickly. Terminal velocity is directly proportional to the sqrt of gravity and the sqrt of the inverse of the drag. So if "proportional" these factors cancel out. [Answer] Your primary premise is flawed. Earth and Venus have comparable gravities but Venus has 90 times the atmosphere. [Venus atmosphere](https://en.wikipedia.org/wiki/Atmosphere_of_Venus) Other planets also differ widely. Saturn is huge but has close to Earth gravity, you can fit 1000 Earths into Jupiter but it has less than 3 times the gravity [Planets gravity](https://www.universetoday.com/35565/gravity-on-other-planets/) Neptune and Uranus are also close to Earth gravity, Uranus is a bit less than ours, yet both of these have atmospheres of perhaps hundreds of kilometres if not more. [Answer] To a first approximation, let's see what happens if we take the existing Earth and its atmosphere and dial up gravity to 2g. * Pressure is just the weight of the column of air above your head. So if $g$ doubles, the pressure doubles. * For a gas, $P \propto {1\over{V}}$ (Boyle's Law) $\rho \propto {1\over{V}}$ so near to the surface, the density doubles too. * Drag (F) is directly proportional to density so it doubles. But... terminal velocity occurs when drag equals weight. So we've doubled the drag but also doubled the weight - so the two cancel out and there is no difference. ]
[Question] [ In my story, those who are transported back in time do not age if they have to live through the years in the past. You don't start aging again until you reach the point in time you left. I was curious though, in this situation, would it still be feasible for one's hair and nails to grow (basically meaning they'd still have to groom themselves)? What would have to happen for these two facts to coexist? Ir perhaps I'm overthinking this. [Answer] Aging is related to the accumulation of DNA damage in the cells. Hair growth is simply a physiological process, like also red cells production in the blood stream and skin renewal. If you stop all the physiological process I think it is going to be pretty hard for your characters to survive in the past more than few weeks: no skin renewal mean no wound can ever heal, just to give one consequence. [Answer] I would suggest that you're overthinking this. Your premise is insufficiently detailed for this question to need answering for your story. The part of your world that you have lots of detail on - go into detail on them. The part of your story that is more hand-wavy: stick with "normal" for details you're not covering, because "normal" will not feel out of place for your readers. So in this case, I would assume your character does grow hair and nails. Think of it this way. Do you think that T.H. White had an explanation for this, for Merlin? No, not in the slightest. And if it was interesting to write about, he would've written about Merlin combing his hair or trimming his nails just like anyone else. [Answer] Assuming that one's body remains constant throughout time travel, you would not age when you jumped to a different time. At least, that's how it is presented in sci-fi - the person steps into the machine, and pops out exactly the same in a different time. Warning: reality might be quite different from stories that sell well. In which case, all bets are off. Relativity suggests that as a person approaches the speed of light, time slows down for that person, to where a one month journey for you the light speed traveler might be a 50 year time span for everyone else. However, that's a one way trip. Relativity suggests you might be able to fast forward, but not rewind. Note than in a lot of popular sci-fi, people don't travel at light speed, they instead warp space/time, so they avoid that paradox completely by just not physically traveling very far. Oh no, I've gone crosseyed... ]
[Question] [ For as long as recorded history, the Earth has had two moons - religions were based around the interactions of these two bodies in the heavens, they were worshipped, feared and romanticised. Then at the birth of astronomy in the 17th century, it was discovered that the smaller of the two bodies was in fact obviously artificial, with hatches, windows, tunnels, structures etc etc. The first manned space missions in the 1950s and 1960s targeted this structure rather than the moon (which was largely forgotten as a goal) and resulted in multiple countries landing at various points on it. Assume an accelerated rate of technological advance into space flight, with such technologies such as space planes, NERVA engines, Orion spacecraft et al all being followed through to a usable conclusion, but not more than 5,000 people being put into orbit between the early baby steps of the 1950s until the current date (circa 2050). Also assume that the structure is not just surface shallow, it is not hollow, nor is it solid but rather its entire volume is a structure, how large would this structure have to be to still be largely unexplored? Edit: In response to queries for further parameters. 1. Assume that the structure is largely operational, with human compatible environmental systems, power, lighting, mass transit, gravity etc 2. Assume that these systems are not necessarily free to use - doors may be locked (eg secure areas, personal accommodations etc), mass transit systems may need a form of interaction not immediately obvious (eg payment), there may be areas of the structure which are exposed to vacuum or irradiated, there may be damage from meteorite strikes. 3. Assume a political climate similar to our own, on a similar time line - there was a cold war which ended in 1990 for much the same reasons. 4. Assume motivations both compatible with a cold war, and also a general public desire for information - for example what does the structure mean, who built it, when was it built, what does it mean for us as a species, but equally the desire to retrieve advanced technologies before any opposing country or faction, to achieve the upper hand before someone else does. [Answer] This depends on a very large number of factors, like how hazardous the structure is and how large the tunnels are. If they're too small for a man in a space suit to fit through then it could take a very very very long time. If it's laid out in a neat grid it will take less time. If it's a rabbit warren then more. If the structure isn't active and isn't trapped and isn't otherwise actively trying to kill explorers etc then I'd compare it to cave diving. They need to carry their own air, they can't go very fast, it's dark, they're in bulky suits, they don't know what's around the next bend. So lets go with cave diving. Cave divers can cover around 15 meters/minute when cave diving. Less if it's tight. Lets go with that. Lets assume living spaces similar to the ISS. So we've got 5000 people who've spent time mapping this. Lets assume that each of them has averaged the same as a tour on the ISS, 6 months each over the course of 100 years. 5000/100 = 50 people per year or 25 doing 6 months shifts. so at any given time call it 25 people resident in stations attached to the structure, perhaps 5 stations similar to the ISS with 4-6 crew each. They're unlikely to spend every waking moment exploring, they need to spend a large fraction of their time maintaining the systems that they need to live or doing work in the explored sections. The longest space walk in history was eight hours and 56 minutes. Lets assume they each spend, on average 3 working days per week purely on exploration for 9 hours solid. More and they're more likely to make mistakes and on space walks mistakes are likely to mean death. Of those 9 hours they can't spend the whole time in new passages. They're going to need to spend time traveling through explored regions to reach new areas and time traveling back. Lets assume 3 hours out, 3 hours exploring "virgin" terrain and 3 hours getting back. They'd probably move their bases to new regions once the trips took too long but I'm probably making pretty generous assumptions. Finally we can make some guesstimates. 15 meters per minute \* 180 minutes per day \* 3 days per week \* 25 people \* 52 weeks \* 100 years 1,053,000,000 meters or a little over a million KM of tunnels. That sounds like a lot but for comparison at 2,500km, the Odessa Catacombs are probably the largest network of man-made tunnels on earth. I can't get exact numbers for the 2D size of the Odessa Catacombs but from some googling they seem to be mostly under an area with about 70 KM diameter. **So if your station was a rough sphere with a diameter something along the lines of 100KM with a winding maze of tunnels roughly as dense as the Odessa Catacombs throughout the 3D structure then we could expect it to have something like 5 million miles of tunnels leaving most of it unexplored even after 100 years.** Specialized tech for aiding the exploration would speed things up massively but then they're unlikely to have as many people up there in the 1960's as later. If you want to deal with that then make the structure mildly hostile to small drones and similar tech unaccompanied by humans. to make this economic they're going to need to be finding something of worth. This would be a project dwarfing the moon landings in terms of cost. They'd need to find something equivalent to room temperature superconductors or working fusion generators every few or so at least. EDIT: Some of the edits to the OP contradict my answer since I was assuming cold, dark, dead tunnels navigated in space suits. However I only considered tunnels, not any of the rooms connected to them so it may still take about as long to properly explore the space. Also live technology allows for more interesting problems like "staff only" areas which attempt to expel our explorers since the system does not consider them staff etc. [Answer] **UPDATE** I have it, but it's not about size, and we've been looking the wrong way. Size doesn't matter, and we need to look down, not up, for examples of unexplored places. If there is sufficient funding, it would have to be absurdly large and absurdly laid out. If there isn't sufficient funding, it has too much economic, military, and philosophical value to remain unexplored. No, instead ***it has to be not too large, but too dangerous***. --- First, why size can't save you. You say there's air, power, lighting, mass transit, even gravity (?!). Setting up a permanent, manned colony on the station would be far, far easier than setting one up on the Moon. You still need to ship humans, food, water, and their equipment *but not air and environmental systems*. There's no issue of bone degradation due to lack of gravity, so they can stay as long as they like. This reduces what you have to launch significantly. ***It makes keeping people on the station closer to maintaining [an Antarctic research base](https://en.wikipedia.org/wiki/Amundsen%E2%80%93Scott_South_Pole_Station) than the ISS***. While getting them there is still costly, many more people can stay on the station for months or years at a time. For example, Amundesen-Scott maintains 50 people over the winter. But people are inefficient. They require food and water and sleep and have to return to base. Instead, ***use cheap quadcopter [drones](https://en.wikipedia.org/wiki/Unmanned_aerial_vehicle) to do the exploring***. They can be controlled by the people on the station, or by the people on Earth, or in a semi-autonomous mode. Drones are light and cheap compared to food and water and humans, so you can send a lot of them. Have the humans there not for exploring, but for drone maintenance and to do the odd thing the drone cannot do. How long will it take to explore your structure? ***With sufficient drones exploring every path in parallel it will take as long as it takes to traverse the longest path***. If your station is laid out with any sort of logic, this will be the time to go from one end to the other, plus time for doors. Room exploring time does not matter except to find the exits, follow on drones and humans can explore what is found in parallel. Just how big? ***At a very modest pace of 1km/hour, 100 years (or 36,500 days or 876,000 hours) means the longest path must be 876,000 km.*** That's over twice the distance to the Moon. If the hallways are roughly 3m x 3m (space for a person to walk, plus piping and wires and structure and such), and we assume the twistiest path possible, that's an internal volume of 7,884,000,000 m3. or 7.9e9 m3. How big is that? For comparison the pressurized volume of the ISS is about 1000 m3 or 1e3 m3 or 8 million times smaller. Reaching for the handy [Orders Of Magnitude By Volume](https://en.wikipedia.org/wiki/Orders_of_magnitude_%28volume%29) (I love these lists) we find it is about the volume of [Lake Thun](https://www.google.com/maps/place/Lake+Thun/@46.7005221,7.448202,10z/data=!3m1!4b1!4m2!3m1!1s0x478fae3554ddf6eb:0xc692ca79d2500aea), a rather large lake in Switzerland. And that's the best case using the most twisty and most nonsensical path. ***Making it so big it cannot be explored by drones in 100 years is impractical.*** You either wind up with a ludicrously large station, or some ridiculous reason why you can't use drones, or an internal layout that makes no sense. --- Now, why it will always been an object of interest. ***If you want to leave something unexplored, do what archeologists do: be wildly underfunded***. As any archeologist will lament, there's acres and acres and acres and acres and acres of unexplored and unstudied ruins and artifacts out there in the world and not enough money to fund the studies. As any archivist will tell you, museums are full of great stacks of unexamined artifacts and not enough money to fund people to sift through them. So, like with exploring the Moon, maybe there was initially a great race in the 1960s to land on the station. After a few manned missions they didn't find the great wealth of knowledge they expected, and public interest and funding waned. Since there's gravity it can't even be used as micro-gravity research and manufacturing. Later, with the advent of cheap spaceflight and cheap drones, universities can scrape together the funding to send one drone to the station, similar to how they can launch micro-satellites now. Other exploration is done by the odd commercial venture to explore the station in search of rumors of those lost ancient vaults of knowledge that must be there somewhere. ...but even this is absurd. ***A large, human-friendly, orbital structure has enormous economic value***. It would be an enormous boon for the space mining and manufacturing industry. It would be used as a fuel and supply station and orbital construction center. Asteroids could be brought nearby for mining. Satellites could be serviced. Spaceships could be built and launched from orbit saving tremendous amounts of fuel and mass. Looking at it from the Cold War perspective, ***it is the ultimate high ground***. Whomever controls the station can threaten to drop a rock on their enemies. No major nation would allow it to remain unoccupied. From another perspective, ***this station is the answer to the eternal question "Are we alone in the universe?"*** It's a big blinking sign saying "NO!" Of course it's going to be explored to find answers: Who built it? How did they interact with us? Where did they go? Can we go there, too? ***Once we can reach this station, we would have no reason to leave. It would be our jumping off point to the stars.*** --- Finally, how to make it unexplored. ***Where on Earth have we not explored? Underground and deep under the ocean.*** Why haven't we explored there? Heat and pressure. Since it's a space station, you can throw in radiation. ***There's lots of reasons why parts of the station (or the whole station) might be too hot, overpressurized, or irradiated.*** Maybe the environmental controls are broken. Maybe it wasn't built for humans. Maybe the power source is overheating. Maybe the radiation shielding has broken down. As we learned at Chernobyl, [even robots do not like working in high radiation environments](http://www.the-scientist.com/?articles.view/articleNo/10861/title/Soviet-Official-Admits-That-Robots-Couldn-t-Handle-Chernobyl-Cleanup/), and even robots have to vent waste heat. This would severely limit how far and how long robots could explore parts of the station. We can't fix it because we don't understand the technology. To us, their technology looks like a microchip would look to a 19th century scientist: a mostly featureless lump. All their essential systems are presumably encrypted far beyond our capabilities. Some of the critical systems are in the hostile zone. We don't care try to disassemble any of it because it might make things worse. We don't understand their language and have no [Rosetta Stone](https://en.wikipedia.org/wiki/Rosetta_Stone) upon which to start a translation. If it is an alien language, we have no basis upon which to perform an analysis. We'd have to try and map glyph (if they even use them) to their functionality of technology we don't understand. Slowly, painfully slowly, we'd do careful experiments to pick apart how (hopefully) minor systems work to learn the fundamentals. We'd develop new instruments and new areas of science and physics to analyze their tech. And then, maybe in 100 years, we'd learn how to fix the station, reduce the hazards, and finally get a look at the core. [Answer] **With 1970's to current space technology, the station would remain largely unexplored for thousands of years even with continuous, dedicated efforts to explore it.** Our moon has a radius of ~1700km. Assuming a "smaller" artifical moon had a radius of 1000km, it had a volume of ~4 million km³. Further assuming an average room/corridor height of 4 meters, accounting for high ceiling halls, outer walls etc., you had to explore an inner surface area of roughly 1 million km², equivalent to [the surface area of Egypt](https://www.google.de/webhp?sourceid=chrome-instant&rlz=1C1EODB_enDE669DE669&ion=1&espv=2&ie=UTF-8#newwindow=1&safe=off&q=surface+area+of+egypt). In addition to the average 4m height of rooms and corridors, further assume an average width of 5m of corridors, where a room is defined as a broad corridor. That would require the exploration of 200,000 km of corridors. Since we are talking about rooms and corridors for the most part, you will only ever see as far as the farthest wall, so whatever area you want to survey, you will have to physically get there. No tool more sophisticated than rangefinder binoculars will aid in the exploration in terms of covering raw area. Human walking speed is 6 km/h; assuming 8 hour work shifts plus breaks, a human could cover ~50 km/day. That would mean 4,000 person-days, or 11 person-years to explore the whole station by foot under ideal circumstances. In practice, this is based on a number of unrealistic assumptions: * No backtracking whatsoever: Assuming the station layout even allows an [Eulerian path](https://en.wikipedia.org/wiki/Eulerian_path) or a division of the station into multiple such paths, the explorers would have to carry all their provisions and equipment from start to finish, which is obviously impossible. Alternatively, someone has had to go ahead and create base camps, which already implies backtracking has occured. This factor alone will increase the time to fully explore to several times the theoretical optimum. * No multiple exploration runs: Locations deemed interesting will have to be visited and investigated multiple times with specialized equipment to count as explored. * No obstacles: The question already mentioned the station being in various states of disrepair and poor lighting, which slows down the average speed of exploration, increases the need for additional tools such as lights or debris cutting/moving tools and requires detours for truly impassable obstacles. * Competition: Since we are talking about a cold war era, political tensions and the direct rivalry of space-faring powers could easily prevent the complete exploration of the station for an indefinite length of time, and might even make the station a battleground. * Simple logistics infrastructure: No matter how many person-years you assume the exploration to require, you have to at least double or triple that number in order to support the actual explorers. They have to eat and drink, require equipment and maintenance thereof, medical assistance, command and communications, maybe even military protection from competing powers. Triple it *again* because everything happens in space. Overall, assuming the political background does not significantly obstruct the exploration into impossibility, we are looking at several hundred person-years as an absolute minimum for exploring the whole station. Let's make it 1000 person-years. In practice, space technology and space-faring economics will be the most limiting non-political factor. The [Apollo program](https://en.wikipedia.org/wiki/Apollo_program#Mission_summary) managed to put a total of 18 people on the moon, for an average of 10 days each, over a time span of ~3 years from the first landing (Apollo 11) to the last (Apollo 17), or 60 person-days per year. **At 1000 person-years required, this would require a continuous Apollo program with a duration of ~6000 years.** Modern space technology will not significantly improve the economics of going to the moon or its smaller brother. The [rocket equation](https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation) still holds as true today as it did in the 1970's. You will still use oxygen and hydrogen as your fuel. You will still have to use multi-stage rockets made of light and durable metals. In order to fundamentally reduce the costs or increase the frequency at which you can send stuff to the moon and back, you would need novel ways of doing so, such as a [space elevator](https://en.wikipedia.org/wiki/Space_elevator) or a [space fountain](https://en.wikipedia.org/wiki/Space_fountain). [Answer] I think you'd need to add a condition - something like once under the surface, remote drones or fast vehicles can't be used (insert reason of your choice) because otherwise you could very rapidly explore using small drones. So with that out the way you are down to people exploring - and the obvious challenge is getting people there. It is incredibly expensive (in terms of cash, resources and people) to get a tiny number of people to the Moon and back. You aren't going to get an order of magnitude improvement on that by 2050. So assume only a small, select group of visitors each mission, and missions, even if you throw resource at them, will not be able to happen continuously - you'll run out of resources, or you'll have an incident that while pause space exploration while faults are understood and fixed (see evidence from the Space Shuttle...) and even something a tenth the size of the moon would not be able to be explored fully. Remember volume goes up as the cube of the radius - there's a lot of volume in a sphere. [Answer] *At first, the great powers rushed to explore the structure. But then **the incidents** happened. Exploration was immediately halted and only restarted much later, but newfound caution - or fear - meant it never recovered its initial gold-rush pace.* What are the incidents? Don't know, but that's a plot in itself, really. Whatever happened ("Icarus incident" has a nice sci-fi ring to it), it has to be wild enough to scare everyone good. It sounds like whoever built the thing aren't around anymore, so perhaps the explorers learned a bit too much about their fate - and learned it a bit too directly - and it wasn't pretty. If, at the same time, the structure has already rewarded the initial explorations with more data than anyone knows what to do with, things could settle down while that's being chewed on and interest wanes. Of course, some will be clamoring for a return to full-on exploration, but people are saying the same for our Moon - and space in general. But generally, people just aren't interested enough to follow through. In the story, that thing has apparently been up there for eons, and doesn't seem to be going anywhere. So let sleeping dogs lie, curiosity killed the cat and all that. Why spend *my* tax dollars just to have more astronauts and eggheads uncover another [redacted] and end up [redacted] like last time? Man, I don't even like to think about that whole thing. So sad/creepy/scary/horrible/gross. --- Or maybe there's simply a very explicit "keep out!" sign and - for once - humankind takes note. At least somewhat. A problem facing us today, for instance, is how to safely store radioactive waste that'll be dangerous for thousands of years. How do you design a structure that's so secure, or simply so *uninviting* that a future civilisation (that may not share any of our culture or understand our languages) will keep clear? [This is a problem that's been studied](http://www.slate.com/articles/health_and_science/green_room/2009/11/atomic_priesthoods_thorn_landscapes_and_munchian_pictograms.html), but of course no one knows if any of the proposals put forward will actually deter future-man. Imagine we found an ancient structure here on Earth. We don't know what it is. We just know it's at least 10,000 years old and appears very deliberately designed by some hitherto unknown civilisation. Would we immediately dig/drill/dynamite our way in? Undoubtedly. Would we stop if we discover that those warning sign-looking things are in fact warning signs, and the structure is actually meant to keep us from unleashing tons and tons of self-replicating, radioactive ebola nanites? No, we'd probably keep digging, because as a species we're not terribly smart. But there'd certainly be a lot of debate, and exploration would be conducted very, *very* carefully, and halted again and again. And a lot of resources would likely be devoted to *keeping people from exploring* because of the dangers it poses. And sooner or later, the exploration will be so slow that it's just not interesting, and is considered a waste of money. --- And, as others have already pointed out, exploration can move in fits and starts. The vikings appear to have sailed to (and made non-permanent settlements in) North America, but everyone remembers Columbus, hundreds of years later. And it took another hundred years and a few decades before the pilgrims landed at Plymouth Rock. A then a few hundred more before Lewis and Clark. Et cetera. [Answer] Some things: depending on what you want the tone of whatever it is you’re making this for to be, a pretty easy way to validate decades of exploration is to make sure it keeps changing. If you want to keep it within the realm of plausibility, then it would probably make sense for this object to be self-maintaining, given that apparently it’s been up there for most of human history. This would probably include repairing, maintaining, and building new things, as well as destroying old ones. Staying in orbit is one of those things that’s really easy for a big ball of rock, but really hard for something that humans which need to stay on the surface of another big ball of rock can survive in. Because Space is Hard. If you want to go with the slightly more supernatural method, then why not throw in some non-Euclidian geometry? No one really seems to know what exactly this thing is and/or where it comes from, *and* it’s mostly unexplored, so it’s not like all the humans back down earth have a good reason why it shouldn’t be bigger on the inside. It can be advanced technology, space distortion, general weirdness, whatever. This works, because historically, most [Big Dumb Objects](http://tvtropes.org/pmwiki/pmwiki.php/Main/BigDumbObject) are supposed to be pretty weird. Also, exploration time really depends on how involved someone is in the process. They could carefully measure, test, and photograph every single door or passage they find, which is actually pretty likely, at least at first. But this would also probably take forever. The other end is you could just draw some rough lines on a map, and call it a day. Or, just wander off and see what you find! Historically, this is more or less how humans found new places for pretty much ever. They put a bunch of guys in a boat, and told the boat to go somewhere and try and keep track of what direction they were going in. eventually, they would hit some beach or another, get out, figure out roughly where it was based on where they were pointed when they started the voyage, plant a flag, get back in the boat, and go home. This is good for filling in rough outlines, and testing things like “Maybe you can’t fall off the edge of the world?” or “I’m pretty sure that India is this way?” Then, after some people have lived there for a while, things start to get narrowed down. Rivers and mountains are found and named, then they work downward, to streams and hills, to creeks and valleys, until every other little aspect of the landscape is all mapped out. This takes a really long time, which is why we’re still doing it. So, I guess depending on how “discovered” something is, speed depends on how familiar it actually is. More habituated areas would take longer to map out, while new excursions are pretty cut-and-dry. Of course, this is all kind of irrelevant if the whole thing keeps changing, but there’s no reason why some parts could change slower than others, or not at all. It could also just get harder the further you go, less hallways and more locked doors. Exploration is really just dependent on how thorough you’re willing to be, and how much stuff is in your way. [Answer] There are some very good answers, but I think they are to pessimistic in view of your edits. * The station has breathable air. I assume it has water as well, and that humans figure out how to get it. The environmental systems would have to pull humidity out of the air. Public restrooms? Parks and fountains? * Can humans figure out how to draw power from the station systems? If there are no easily accessible sockets, perhaps they will learn to vandalize light fixtures. From these, I expect that hydroponic gardens are possible. Bring plants, use the water, use human excrement to supplement the initial load of fertilizers. This will greatly reduce the supply problems if you eyeball the list of supply missions to the ISS. * The station has gravity. I take that as a close-to-earthlike gravity which allows people to stay healthy for long periods. If transport costs remain high, people could serve for decades at a time. Think of Brits going to India in the 19th century. * The Apollo program went as high as four launches in one year. Assume that level is sustained all through the 1970s, and *nobody goes back*. 660 man-years. * The Space Shuttle program suffered setbacks. Assume that a level of ten launches per year is sustained through the 1980s and 1990s, each with ten passengers in addition to the crew. Again the passengers don't go back anytime soon, but we'll allow the Apollo-era crews their first shore leave. 5,500 person-years in the 80s, 15,500 person-years in the 90s. This gives a total of 21,660 person-years to explore the station. Say each person-year gives 300 workdays of 12 hours each. That should be low enough to prevent mutiny, high enough to satisfy the taxpayers back home. That accounts for 2,120 people going into space, 120 on Apollo capsules and 2,000 on shuttle flights. As you can see, the contribution of the Apollo flights isn't all that great, so it won't change the total much if they spend most of their time developing techniques to live on the station. 50% of the work goes into "life support" for the expediton. Running those hydroponics, darning old socks instead of using new ones, transport of food and supplies where you need them. Another 25% goes into "starside R&D" like figuring out how that subway works or why there is gravity. That leaves about 20 million hours of "exploration and mapping" duty. Now you need assumptions about the average room and corridor size. Imagine a four-person team moves forward at 1 km per hour and covers a corridor with adjoining rooms, 20m wide and 4m high. Each person-hour explores 20,000 cubic meters of the station. That means 400 billion cubic meters are explored. (For that rate of progress, I'm assuming they will open most doors and just glance inside. "Yep, another family apartment. Just like the last one. Write it up and go on.") A billion cubic meters is a cubic kilometre. So they could explore a cube roughly 7.5 kilometres on a side before the turn of the century, and without any new launch vehicles. The design of the station would affect this greatly. Just doubling the average ceiling would double the mapped volume. Of course there would be expeditions to the center of the station, and so on, the mapped area won't be a cube. A 120-km sphere like the first Death Star would do nicely to leave plenty of unexplored space. BTW, I haven't talked about robots yet. They might be able to help with the initial survey of major corridors, disused subway tunnels, etc. [Answer] The Great Pyramid in Giza is roughly 91 million cubic feet in size. It is estimated to be around 4,600 years old and we *still* haven't fully mapped it out. So, taking into account the #3 and #4 requirements I'm going to estimate that the structure would have to be no bigger than the Great Pyramid. Which, obviously, is far far smaller than the moon currently is. The issue isn't in how fast a team of robots could go through and build a virtual map of the station. The issue would boil down to conflicts between political, religious and scientific entities. Some simply wouldn't want it explored as that might be seen as "desecrating" a holy site. So, those people would have to be appeased by going slow and being extremely careful in how results are published. The scientific community would have legions of people trying to build their careers on coming up with what everything from the smallest scratch means to what the rooms where even used for (hint: archaeologists default position is to always claim religious activities). Also, these people would want to be as sure as possible that each room they enter is left in the same state as absolutely possible so you can forget scanning a room, then moving onto the next one as quickly as possible. And god help them if they find writing of any sort anywhere. Politicians would want to ensure that their particular countries/states/etc would benefit from the exploration so it'd take a while to put together teams, assign them, replace them, etc. There would be work stoppages as discoveries are made and the benefits/conflicts from those discoveries are doled out. Finally, we have the ever evolving nature of the global political situation. As countries go to war or find themselves financially unsound, work would necessarily stop until those issues were resolved. Also you can pretty much guarantee that if the thing is of a sufficiently large size that one or more countries would be planting a flag on it and claiming total dominance.... Yeah, 100 years to explore an ancient structure isn't a whole lot of time. ]
[Question] [ Life on Earth pretty early on settled on [deoxyribonucleic acid](https://en.wikipedia.org/wiki/DNA) organized in chains of base pairs as the means to code for the construction of proteins which make up a lifeform. It also has the benefit that it can be biologically copied relatively simply and accurately. But why would life that has evolved separately from Earth life end up with the same solution to the problem of coding for construction of proteins and inheritance of such coding? The specific base pairs in DNA are [cytosine](https://en.wikipedia.org/wiki/Cytosine) ("C", C4H5N3O), [guanine](https://en.wikipedia.org/wiki/Guanine) ("G", C5H5N5O), [adenine](https://en.wikipedia.org/wiki/Adenine) ("A", C5H5N5) and [thymine](https://en.wikipedia.org/wiki/Thymine) ("T", C5H6N2O2). These happen to be able to form the fairly well-known "double helix" DNA structure. Here already we can see a strong dependence on an environment rich in carbon, nitrogen and oxygen (as well as hydrogen), which works well on Earth and with Earth life. Assuming that life develops independently (no common origin) on different planets, possibly in different solar systems, each able to support some kind of life which may be either similar to or dissimilar from Earth life, **is there any plausible reason, or plausible set of criteria, why life would happen onto specifically DNA** (as used by Earth life) on different planets? Or is it simply a random chance thing and there is no reason whatsoever why alien life wouldn't just as well happen onto something utterly and completely different that solves the same problem? Please note that I am not asking about the specific proteins being coded for, or the mechanism by which DNA is used to actually drive protein production, or the need to find a solution to the problems that DNA solves in Earth life, but simply about *the use of specifically DNA itself.* If you want to address those issues as well, then feel free, but they are not the focus of this question. I'm not going to tag this as hard-science, but the harder the science in the answers, the better. [Answer] # Because those nucleotides occur naturally. ...probably. We've been finding the building blocks of DNA on meteorites for a while now. [According to NASA](https://www.nasa.gov/topics/solarsystem/features/dna-meteorites.html) there's a good chance they occur naturally. > > *The team found adenine and guanine, which are components of DNA called nucleobases, as well as hypoxanthine and xanthine. ...Hypoxanthine and xanthine are not found in DNA, but are used in other biological processes.* > > > *Also, in two of the meteorites, the team discovered for the first time trace amounts of three molecules related to nucleobases: purine, 2,6-diaminopurine, and 6,8-diaminopurine; the latter two almost never used in biology. These compounds have the same core molecule as nucleobases but with a structure added or removed. ... "However, if asteroids are behaving like chemical 'factories' cranking out prebiotic material, you would expect them to produce many variants of nucleobases, not just the biological ones, due to the wide variety of ingredients and conditions in each asteroid."* > > > And [we've been able to produce them in the lab using non-biological reactions](https://www.nasa.gov/content/nasa-ames-reproduces-the-building-blocks-of-life-in-laboratory). > > *Thirdly, the team found these nucleobases -- both the biological and non-biological ones -- were produced in a completely non-biological reaction. "In the lab, an identical suite of nucleobases and nucleobase analogs were generated in non-biological chemical reactions containing hydrogen cyanide, ammonia, and water. This provides a plausible mechanism for their synthesis in the asteroid parent bodies, and supports the notion that they are extraterrestrial," says Callahan.* > > > *NASA scientists studying the origin of life have reproduced uracil, cytosine, and thymine, three key components of our hereditary material, in the laboratory. They discovered that an ice sample containing pyrimidine exposed to ultraviolet radiation under space-like conditions produces these essential ingredients of life.* > > > Rather than being a fluke that happened once on Earth, DNA, or at least its building blocks, appear to occur naturally. So another planet would have the same chemical base pairs available for proto-life to produce DNA. DNA and RNA are *very* good at what they do: encode the blueprints for an organism very efficiently, accurately enough to ensure stability, but allowing sufficient inaccuracies for evolutionary variations to respond to changes in the environment. It's so good at what it does that despite billions of years of evolution and endless variety ***no life on Earth does anything else***. This implies that even if several competing forms of life arise on another planet, DNA/RNA based life will win. # RNA might be more likely. Just because the base pairs are there doesn't mean you get DNA. You might get RNA first, known as the [RNA World Hypothesis](https://en.wikipedia.org/wiki/RNA_world). RNA has many of the properties of DNA which are important to life: it's self-replicating, it can act as a catalyst, and it can make proteins. RNA is more fragile, making it suitable for only simple life, but that's exactly where life starts out. [Answer] Having compatible DNA is very unlikely, just about the only way it could happen is if you had some form of cross contamination, like a panspermia event. Just having DNA may not be hard but have a compatible sequence (same nucleotides and/or codons) is just too unlikely to be believable without a common ancestor. [Answer] **RNA is basic, DNA is sophisticated** It took a long time for life on earth to switch from a purely RNA based genome to the more stable DNA. RNA is still essential for life processes. RNA is chemically simple and its ingredients are sythesised in Urey-style experiments. So it is pretty likely that an alien lifeform will use RNA as an information encoding molecule. It may later develop DNA or something different. **While RNA is basic, the code is arbitrary** An exobiological life form will for sure have a different genetic code being incompatible with the Earth's life forms. Even if it uses the same bases (they look quite optimal for their purpose, but so-called exotic bases exist in nature and can be synthesised by chemists), the mapping to aminic acids is completely arbitrary and will be different for sure (for statistical reasons). The set of aminic acids will be also different. **There may be mirror life** Sugars, aminic acids, and bases are asymetrical molecules, they have mirror images with the same physical features (melting point, acidity, etc.) but that are still different. Biological life has selected for a long time one of the mirror forms to build their more complex molecules from and cannot use the mirror images in general. On another planet, the mirror images of the Earth's molecules may be chosen by life. [Answer] **EDIT**: After some edits to the question, I think the bulk of my answer is not directly relevant as the question seems to be asking about the physical molecule of DNA and not an abstract idea of molecular organization. Given this, my response would be the "short answer" below. --- **Short answer:** no **Long(er) answer:** it depends **Long answer:** I think a point of clarity here is what you mean by DNA. Do you mean literal, biological DNA the molecule, or the higher level concept of DNA as a molecular scale data storage mechanism? If you mean literal DNA, then I would say that the chance is pretty small, approaching impossible. Convergent evolution can only explain so much, and the odds of two completely independent ecosystems evolving exactly the same solution to a problem is incredibly small. However, if you mean DNA in a more abstract sense, then I would say that it is all but guaranteed. Most [definitions of life](https://en.wikipedia.org/wiki/Life) require a few key properties: * Input/output of energy * Self replication/perpetuation * Signaling (read: communication) The most relevant of these properties to this discussion is self replication. This requires some form of data storage at some level. Here on earth, organic organisms use DNA to store information from generation to generation and to differentiate between different types of organism. DNA has a few key qualities that make it ideal for this task, again speaking in high-level, abstract terms: * Recursive (it contains the instructions to read, build, and modify itself) * Malleable (can be modified during replication, either intentionally or by chance) * Simple structure (very basic components, four base pairs, are used to form very complex output) While we obviously do not know for certainty, it seems reasonable to assume that any sort of complex life would require some similar mechanism that accomplishes these goals as well. [Answer] **We don’t know for sure, but probably not** There are so many possible different chemical variations that it would seem unlikely in the extreme that a rerun of evolution would arrive at exactly the same “design”. Whilst a lot would be down to the exact conditions present, a lot would also be down to chance. Assuming that the life on this alien world was carbon and water based (reasonable assumptions but by no means a given). And assuming that some form of sugar based acid is going to be used (hard to be certain, but I would have thought there are plenty of other arrangements of molecules that could do the same job) and assuming that it happens to be pentose sugars that are use (rather than hexose sugars) then there is still a fair amount of choice as you can [see here](https://en.wikipedia.org/wiki/Pentose). Even assuming all this there are lots of potential bases other than pyrimidines and purines and a good variety of pyrimidines and purines as well. Although not as famous as those of biological importance, there are plenty of variants available as can be seen by looking through [this index](http://onlinelibrary.wiley.com/book/10.1002/9780470187944) I would say the best way to ensure that DNA was found as the building block of life on another planet would be to make sure that the conditions on the alien world exactly matched those on Earth and additionally to assume that *DNA is the only possible solution to the problem*. Although this is a very big ask, it might just be that there is only one way of solving the problem using the chemistry available to life on an Earth like world (we don’t know for sure). If this were the case then I think that it would be a suspiciously god like coincidence. And we might even imagine that intelligent humanoid life forms are the best solution for any land based animal and if we are not careful we can persuade ourselves into a star trek like universe where all the aliens are basically just like us ;o) [Answer] There are other methods to store genetic information similar to DNA that *we* have discovered. They are called [XNA](https://en.wikipedia.org/wiki/Xeno_nucleic_acid) for short. I would assume, there will be different way to code genetic information in the universe, however, DNA would be one of them. So far, we know 9 other methods. If you incorporate other genetic methods into your universe, but explain that your story is passing on the worlds with DNA due to compatibility reasons, no one will question the science behind it. After all, this evolutionary path has been taken at least once, there is nothing that stops it to be taken more than once. You can also consider using RNA as it is simpler to form and statistically speaking should be more abundant. RNA is compatible with our biology thus RNA based life forms can (and does) infect humans or can be used as food source. [Answer] DNA isn't necessary for life, but the instructions on how to function, how to reproduce, and the imperative for improvement, are necessary for life. You could implement those instructions in a variety of ways - in the book/film The Andromeda Strain, the foreign life was of a crystalline structure that thrived and grew under radiation. How that worked, the story didn't explain. So to consider your hypothesis, you need to consider exactly how DNA is used in a living cell. It is not DNA itself, but the instruction sets contained in DNA sequences, plus the supporting chemical structures, that enable life to function, just as a microprocessor by itself can't do anything. It's the instructions executed by the microprocessor that makes the system functional. The living cell exists by executing instructions found in DNA, or in the case of very crude bacteria, the simpler and less long lived RNA. This miniature 'computer' runs on chemicals and not electricity, and it has no 'clock' (though it can multitask like crazy), but like a microprocessor, the cell executes an instruction set in response to stimuli (both internal and external), to achieve a desired goal. On top of the 30k or so instructions in DNA, plus a backup copy, DNA also contains templates for the multicellular, multiorgan creatures. This chemical software has been running for a few billion years on earth, fixing itself, reproducing itself and improving itself. Consider also that as far back as we can find identifiable complete DNA strands, around 150-200 million years in bugs trapped in amber, the basic components and representation of instructions (4 chemicals, always referenced in groups of four... a 256 bit medium), have not changed. The templates for the creatures have evolved considerably, but not the basic instructions. The basic functioning of DNA does not appear to be evolving, although it does facilitate evolution of the templates. Some of the instructions in DNA may well predate life on earth. Evolution in a living creature, as in variations in the DNA, only happens during reproduction when the DNA replicates, or a new strand is combined from two donors in the case of sexual reproduction. So how did living creatures evolve to reproduce, if reproduction is necessary for evolution? The living cell had to come into existence with the ability to reproduce, which also happens to be its most complex function, or it would not survive, let alone evolve and thrive. It is interesting to note that, as far as we can determine, life on earth began not too long after the ecosphere changed to conditions that would support life, as in temperature, presence of water, etc... almost as if life was waiting for those conditions. Perhaps the basic instructions in DNA for functioning and reproducing/evolving aren't the result of random chance, but a deliberate effort. By whom and for what purpose might make for an interesting story. You can accomplish the same goal with mechanisms other than DNA/RNA/amino acids/proteins. As it is, DNA and the supporting chemical structures are an elegant solution that has been proven on earth for a few billion years... repairing itself, replicating itself, and improving itself. Life, as far as we can observe, is the only entity in the physical universe that appears to be following a coded instruction set to improve itself. Science has never observed a rock or a body of water consulting an internal instruction set on what to do next. [Answer] One of the currently most supported theories on where life came from, states that [we're descendants of bacteria that came to Earth with a meteorite](https://en.wikipedia.org/wiki/Panspermia). Given how far comets can travel and how often they presumably crash into other celestial objects (if you consider the impact of gravitation on their route), it's not too unlikely that extraterrestrial life would be descendants of the very same bacteria - the evolutionary line would, of course, split up long before the bacteria would have arrived on Earth, but probably not yet before DNA or at least RNA developed. So, if we and the aliens happen to both have evolved from the same bacteria species that already had DNA when evoluton split up (which is, as explained above, not quite far-fetched), it's extremely likely that the genetic structure is DNA-based for the aliens as well - it hasn't changed much, as it seems, during the long travel of the bacteria across space to Earth, so it appears to be quite stable. It might be well-imaginable, though, that the aliens developed some comparably minor changes in the structure, thus having, say, 5 pairs of nucleobases rather than 2 like humans. Since earth life is the only known example, there's no telling how likely that is. I think this information would be pretty much solid enough to build your entire concept upon, and the idea to be relatives of the aliens via a "life before life" of sorts might have some interesting impacts on the story. [Answer] ## There are people who speculate that DNA predates life So the short answer is that with only one data point we don't know if DNA is super-special (I personally don't think it is) In <https://www.newscientist.com/article/mg21528795-500-dna-could-have-existed-long-before-life-itself/> it is speculated that DNA existed before life started to use it which would indicate to me that early life might well have just been using what was handy and another planet might well have something else handy. [Answer] I can't say for sure, but the DNA/RNA system works wonderfully well. RNA might be better for simplicity. Think about it: Each three-base pair codon codes for a specific amino acid (although some different codons are for the same amino acid, e.g., Alanine is coded for both by mRNA codons GCU and GCC (DNA codons CGA and CGG)) The essential amino acids (for us) are the twenty covered by these codons, as well as start (Methionine, mRNA codon AUG) and stop codons (mRNA UAA UAG and UGA). You usually only have 2 types of DNA: DNA and mtDNA (mitochondrial). But RNA comes in many types: mRNA (messenger) tRNA (transfer; it brings the amino acids to the ribosome coded for by mRNA) lncRNA (long-noncoding) rRNA (ribosomal structural) crRNA (CRISPER RNA, used as a guide for the restriction enzyme Cas-9) snRNA (small nuclear.) and viral RNA (Which is unusual in that it can be double-stranded. Then agian, viruses also can have single-stranded DNA, so not so unusual.) ]
[Question] [ Average Joe was an amateur astronomer. While he was out in the wilds one day with his telescope he was kidnapped by aliens, carried off and kept as a slave on a world somewhere in the Milky Way. Having learned enough of their language and technology to steal a ship he now needs to find his way home. The ship is powered by narrativium and travels at the speed of plot, it's guaranteed to get him home before his dog dies as long as he points it in the right direction. What knowledge could Joe have that would allow him to find his way home, or is he lost forever? [Answer] That will not be easy. Our galaxy is about 100 000 ly across and you can see Sun with naked eye at 80 ly at best. Of course you can see a lot further with a telescope but there are [4–16 billions](https://www.quora.com/How-many-yellow-dwarf-stars-are-in-the-Milky-Way-Galaxy) of yellow stars, that would look like Sun from afar. But it would be possible if we postulate perfect memory of Joe(or all necessary data saved on his laptop) and ability to do as much as hyperjumps as we need for any distance in a short time. As it was already mentioned you can narrow the area with image of the galaxy. [![Galaxy and Sun](https://i.stack.imgur.com/pbax4.jpg)](https://i.stack.imgur.com/pbax4.jpg) But that would not be enough. As you go somewhere around that part of Orion Arm you still will be thousands ly from the Sun and there would be millions of stars around. You will need to look for extremely bright stars - above 100 000 of Sun's luminosity. A star like that would be one of the brightest stars on the sky even when seen from several thousands ly. If you do several 100 ly jumps you will see that most bright stars will go bleak and only our candidate will "move" with us. We can find only several stars like this several thousands ly around, some of them would be [Deneb](https://en.wikipedia.org/wiki/Deneb), [Aludra](https://en.wikipedia.org/wiki/Eta_Canis_Majoris) or some other star from the [list of brightest stars](https://en.wikipedia.org/wiki/List_of_brightest_stars)(look for the distant ones on this list). Now we can start to look at colors of those stars and distances between them. By doing this we would be able to get exact names of the stars. Now we will be able to narrow our search to some hundreds of ly. There we will do the trick again, only this time we will look for less bright stars like Sirius or Vega. After this we will have to check only several stars to get to the Sun. [Answer] Going home can be easy, or it can be very hard. 1. Very easy. Spacefaring aliens should have not only comprehensive stellar catalogs, they should have space equivalent of "Google Maps". If Average Joe knows the name of the Sun in alien language - problem is solved in one step. If he doesn't know the name, he can search for specific type of star with specific planetary system. Planetary layout supposed to be as good as stellar fingerprints - all exoplanetary systems known so far are different, and none is like our solar system. 2. Easy. The database does not contain planetary data, but it does contain star data. Look for [Alpha Centauri](https://en.wikipedia.org/wiki/Alpha_Centauri)-type ternary system, and look for G2 class neighbor. There must be not too many to choose from. 3. Hard. There is no database, and your traveler must make his own observations. Depending on the instruments he has it may take some time, or make the whole task impossible. It would also be very important what specific knowledge this amateur astronomer has. If he knows the general distance of the Sun from galactic center and relative position of it with respect to outside markers like [Andromeda galaxy](https://en.wikipedia.org/wiki/Andromeda_Galaxy) or Magellanic clouds, the search can be greatly narrowed. If not, he has to locate bright stars that would match Sun's neighborhood, like [Canopus](https://en.wikipedia.org/wiki/Canopus), [Betelgeuse](https://en.wikipedia.org/wiki/Betelgeuse) and [Deneb](https://en.wikipedia.org/wiki/Deneb). It is also worth noting that Sun's region may not be directly observable from his current location within the galaxy. [Answer] **Joe is lost forever, unless…** Let us assume for a moment that the aliens have transported Joe to their home world and by coincidence it is only 200 Light Years away from Sol. Within a 200 Light Year cubic volume near Earth, is approximately 32000 stars. Joe is not going to know that any given binary star might possibly be Alpha Centauri because it is 4.2 LY away from a G2V star, simply because the database available to him will not contain understandable stellar classifications, nor will it contain understandable distances. Joe may recognise that he is somewhere in the correct place near the end of the Orion Spur. Now if the alien home world is further away, let us assume that Joe can find his way back to the Orion Spur, he is still going to be hopelessly lost at that point. **The Pioneer/Voyager Maps** There is one possible way for Joe to find his way home, and that is by triangulation of the signals from Pulsars, as shown on the Pioneer Plaques, but again, that poses its own unique problems. [![enter image description here](https://i.stack.imgur.com/08z3U.png)](https://i.stack.imgur.com/08z3U.png) <https://en.wikipedia.org/wiki/Pioneer_plaque> Maps on how to find the Earth were attached to the Voyager and Pioneer probes. Does Joe have a photographic memory, and has memorised the map? Or when Joe was abducted he was carrying a book containing an image of the plaque? Not only are the periods of each pulsar encoded as binary, but the approximate distances to each pulsar are drawn on the maps. Now, the pulsar periods are not only in binary, but the time intervals are specified on the Plagues in terms of hydrogen, so Joe could use the Ships computer to translate this into the Aliens time intervals. <http://www.johnstonsarchive.net/astro/pulsarmap.html> Joe could pull up the list of galactic pulsars and triangulate to find the approximate position of the Sol system, and this will give him a position within tens of light years. Further triangulation can be made by looking up the nearby Supergiants and identifying Betelgeuse. [Answer] I would bet that if aliens are travelling the stars, they probably aren't doing it without computers aiding in the navigation. Maybe with his amateur astronomy he can try to travel home by figuring out what the aliens call his planet. If he can't do that, maybe he can use his skills to narrow the nav computer's search. Maybe he can travel to a lot of systems with the right type of star, then explore to see if the planets are what he expects. He could also try to fly until he finds familiar constellations, then get help from the nav computer to try and "Get back" to the exact celestial patterns seen from earth (or at least close enough). I'm imagining him drawing Orion's Belt on a tablet, then asking the computer to find a similar pattern in the sky. Maybe the computer finds a few possibilities (the constellation would look different depending on where he was in the galaxy) and he has to fly certain directions to line things up correctly. Next he doodles the Big Dipper and tries to find another match. Maybe that's not very realistic, but with enough narrativium he could try it. Also, maybe there are more than one type of alien he could meet or get help from. [Answer] If he is an amateur astronomer then he'll probably know at least some of the stellar properties of solar systems near to us. Assuming he has access to an extensive alien stellar library and can match their data to what he is familiar with, he might be able to screen out the billions of G type stars that aren't our Sun. Alpha Centari is a binary (really a trinary solar system with binary suns and a distant red dwarf), Sirius A and B is a binary system, the flare star Ross 154, etc may be enough to narrow down potential Earth systems to something he could reasonably check within his (dogs) lifetime. Even more so if they also catalogue planets/moons. Of course the age of the library will have to be taken into account, proximity to other stars is pretty variable over millions of years. Once he is very close, say 100 light years or so, then he may be able to pick up radio emissions, but realistically those signals are far too weak to receive more than a few lightyears away so that won't really help unless the aliens have REALY good detection technology. [Answer] The big problem with using the proposed images of the galaxy to navigate is when you're in space, you're essentially underwater in terms of movement (but with no bottom and no surface). It's nowhere near as easy as just following a linear path to get somewhere, and you have no idea which direction you're facing and which direction the galaxy is currently facing - direction doesn't even mean anything. ryanrr's suggestion of an on-ship computer is sound. It's unlikely that everyone in this society is some kind of genius, our astronauts couldn't build the spacecraft they rode in on or get themselves to the moon without ground control crunching the numbers, and it's unlikely that these alien astronauts/interstellar kidnappers could do so either. Assuming ship's computer was made to not recognize authorized pilots, and was developed with simplicity in mind for these burly, kidnapper types, Joe should be able to tell it to search for star systems with planets - if this race thinks it's cute to take slave labor from wherever in the galaxy, they've undoubtedly done a great job cataloging every star system they've discovered, possibly with a list of inhabited planets (if any), so they can go back and grab more free workers when the last set they abducted keel over. These undoubtedly come with a relative set of coordinates (which update over time in accordance with galactic movement), for quick and easy navigation. [Answer] **The Hansel Maneuver.** [![Hansel and Gretel and trail of pebbles](https://i.stack.imgur.com/3qU1D.jpg)](https://i.stack.imgur.com/3qU1D.jpg) Hansel knew he would be lost in the deep forest. So he left a trail of pebbles with which he and his sister could find his way home. As he is abducted, your hero should realize the same thing that Hansel did, and surreptitiously leave a trail behind him as he travels. Then he has only to follow the trail to find his way home. The problem: space is big. What to leave as a trail? I was initially thinking he could leave these. [![LED pig](https://i.stack.imgur.com/oQaxF.jpg)](https://i.stack.imgur.com/oQaxF.jpg) These things will blink a long time, work frozen in ice and do not care about vacuum. But even though they blink in different colors I suspect they would be hard to see at cosmic distances. Not impossible, if there was not much else around and you were an artificial intelligence with a telescope and image analysis. Would some sort of radio emitter be better? A periodic chirp. One could search for the next from the vantagepoint of the last using a big dish to establish direction. Maybe that only seems better to me because we are used to seeking visible light EMR with our eyes, but seeking other parts of the EMR spectrum with machine aid. I submit this idea because it is different from what answers are here already (which add up to pretty dim prospects for our hero, it seems to me) and plausible given sweet space MacGyver skills - not because it is a thing sure to work. [Answer] So, I mean, his captors know where his planet is / was, yes? If Joe is somehow using their ships, he would have the ability (in theory, and perhaps not the *access*) to read their star charts. If he has their star charts but doesn't know exactly which star on the chart is home, he could use his own knowledge of the stars near Sol to narrow down his search. "Hey, this one has a binary system about 4 LY away, and is 800 LY from this one which I *think* might be Rigel..." And narrow down from there. [Answer] Milky Way is rather simple galaxy. You just locate the bar (get it, bar, in the Milky Way). Then by galactic longitude the Orion spur and at the end is our sun. Then just go where our solar system is and voila. The place of our sun in galaxy shouldn't be a secret to amateur astronomer. [![Galactic Longitude](https://i.stack.imgur.com/7jKjl.jpg)](https://i.stack.imgur.com/7jKjl.jpg) ]
[Question] [ I am trying to build a city populated almost entirely by monsters, but I am having difficult conceiving a power structure that can exercise proper control over this city. Given the evil dispositions of the variety of monsters within the city, what power structure might be constructed by the creators of the city to allow the city to last? A few points: 1. The creators, [Mind Flayers](http://forgottenrealms.wikia.com/wiki/Mind_flayer), have access to a variety of mind-control magic and require a constant supply of fresh human brains to survive. 2. The creators have access to a large variety of magic and labor; they can construct almost anything that might help. 3. The world has medieval-level technology. 4. The city should be open to all creatures who follow its laws, including humans, dragons, demons, and other monsters. (Structures will be along the lines of [How does one design a city meant for creatures of greatly varying sizes?](https://worldbuilding.stackexchange.com/questions/30228/how-does-one-design-a-city-meant-for-creatures-of-greatly-varying-sizes)) 5. Passage to and from the city is easily controlled because it is underground with several specific entrances. The problem that I have run into while considering this power structure is that given the large variety of powerful, evil inhabitants, it seems that the city would collapse eventually under a creator-run oligarchy unless these inhabitants are managed well. **How can the creators use their resources to create a lasting, open city of monsters?** [Answer] So I am going to approach this from synthesized Forgotten Realms/political science perspective (I love being able to say that). **So your mind flayers.** Mind flayers are crazy powerful. They can control the minds of the weak willed and make them their pawns and eat the brains of basically any intelligent creature. You mention they have to eat human brains specifically, not sure if that is necessary in your world or not. Psionics are neat..and scary. **The scales of society.** In the forgotten realms perspective you have both the *evil/good axis* and the *law/chaos axis.* Good and evil is pretty obvious and you already mentioned that the city is predominantly inhabited by evil creatures. Evil doesn't necessarily mean crazy though. An evil setup can be just as lawful (often times moreso) as a good setup. Just a few of the many examples that come to mind, both real and fictional. * Luskan and Thay (forgotten realms) * Qaddafi's Libya, Saddam's Iraq **So how do they create and maintain a city.** This is pretty standard (apart from the brain eating) dictator 101. **Tools to maintain power** * Power (both information and violence) Information is a big one in this scenario. Mind Flayers can generally read the minds of creatures around them at will (adventurers being able to sometimes resist). With that kind of ability you can know the secrets of virtually everyone. Heck they could make it a prerequisite that to enter the city everyone allow their mind to be read. *Knowing everyone's secrets can give you a great deal of control over them.* Violent power will probably come in the form of dominated thralls and willing thugs wanting to serve the powers that be. Basically hit-men and secret police. The violence doesn't have to stop what most *good* societies would consider crime it just has to maintain the power structure and reinforce the fact that the flayers are not to be messed with. Thieving and murder would be ordinary and the police would not need to care so long as it didn't impact leaders. * Fear The idea of having my brain eaten by a tentacle faced monster that I can only assume has a beak like an octopus is terrifying. * Mistrust Sowing fear and mistrust among the populace. If the people don't trust anyone, and after all most anyone *could* be a thrall its tough for them to organize and overthrow the government. * Money and resources Control them...control the peoples...er monsters I guess. **All in all** its really not that hard to fathom, its actually likely easier for the flayers to pull this off than it is in our world and it happens an unfortunately often number of times in reality. [Answer] You might be very well served if you were to read "The Prince" by Machiavelli for tons of detail on how to pull something like this off. Machiavelli only envisioned humans, but he was extremely cynical. Outside of that, Your Mind Flayers could set up a fairly low maintenance power structure that could handle all of the nastiness they invite into the realm. Set some fairly basic rules. the fewer the better. Things like "Don't kill your neighbor in the city unless you have a really compelling reason to do so, and no, "I'm Hungry", is not a good enough reason". Think along the lines of the John Wick movies: "No business is to be conducted in the Continental". Make your very few rules punishable by swift, gruesome, death at the hands of the mind flayers. Make executions public and very painful. Make the rules local to just the city and surrounding area itself. If you kill your neighbor and eat him in the forest outside of city limits, no problems. Enforce super strict secrecy. Have the city limits stretch well beyond the actual underground lair and make everyone go well outside, away from the entrances in order to be outside the city limits. You don't want nosy villagers coming around and hiring murder hobos, aggressive clergy, and other idiots to come and mess your place up. One last bylaw, If you do kill something within a certain radius of the entrance, leave no trace of it. Consume the carcass completely and remove any evidence that the victim was there. Violators of this rule don't get to die quickly. Finally, Outright kill anything that might be strong enough to resist the mind flayers. You don't want anything getting ideas. To carry on with the D&D theme here, keep in mind that the Chaotic Evil types aren't really going to thrive here. They may come and hang out for a bit, but sooner or later they will likely violate one or two of your rules and the Mind Flayers get a snack. These are some simple ways to keep a variety of monsters in line. [Answer] **What is a city?** A city is a deck of many things to many people: 1. The name itself, city, comes from the same Latin root as Citadel -- **a place strongly held**, a place of safety for those within. 2. **A place of commerce and interactions**, where people come to trade what they have in excess for what they lack. Physical proximity allows easier interaction. 3. **A seat of power** projected over a neighboring area, each city has a natural support basin. This includes the imposition of law, an agreed upon set of behaviors and corresponding penalties for infringements. What does this mean for our city of so-called monsters? In a world where magic is real, where honest-to-god magic-resistant fire-breathing dragons roam the land, where mind-flayers literally feast on human brains, humans are most definitely not at the top of the pecking order here. However, all the power dynamics of groups of rational selfish actors are still very much in play. Since the existence of the city is a given, we can make a few assumptions about the city that must be true or the city would not exist: * The Flayers have sufficient numbers, sufficient cohesion and sufficient overall power to be the dominant power in the city. I.e. no roving [Bhaalspawn](https://worldbuilding.stackexchange.com/questions/9774/how-could-a-group-of-6-people-destroy-an-army) or flight of dragons or dwarf clan can simply waltz in and ravage the place or seize control. This must therefore mean that the Flayers number at least in the hundreds and quite likely in the thousands. * There is a reason why the Flayers maintain the city open to non-Flayers and non-thralls, i.e. independently willed actors. This could be trade, military alliances, or other political arrangements. * There is a reason why other monsters and creatures (even free humans) would consider entering or even taking residence in the city -- there must be something to be gained from entering a flayer nest. This means that the Flayers are able to restrain themselves from psionic attacks agains all comers, and are able to impose a degree of order and some level of violence control and contract enforcement. Most likely candidate is money, or whatever the average monster values. It could also be that as a society predicated upon the consumption of sentients, certain practices and behaviors are considered acceptable here while frowned upon in the rest of the sentient world out there, such as ritualistic sacrifice, various types of blood magic, interactions with powerful demons, etc. * Since the OP states that Flayers need a fresh supply of sentient brains, and since we have determined that to maintain independence, the Flayers must number at least in the high hundreds, a steady supply of human or humanoid victims must be provided. Assuming a rate of consumption of 1/week, the flayer city must consume at least 50,000 and possibly as high as 500,000 sentients per year. While sentients can be violently acquired through warfare and enslavement, this would place the Flayer at some degree of personal risk, which seems unacceptable when it comes to something as basic as feeding for a creature as sophisticated as a Flayer. It thus seems reasonable that any sizable Flayer city would maintain a herd of sentients for consumption. With humans reaching reproductive age at about 15 and possibly sooner given magical stimulants, and the average human female able to bear 1 child every other year, there would need to be several hundred thousands, perhaps 1 million sentient feedstock (90% of whom would be children), making the city one of the largest in the medieval setting world. Even if a significant fraction of the feeding needs could be externally provided (a steady stream of slaves), there would come a point where the cost of maintaining and growing an in-house supply would equal the (presumably nontrivial) cost of acquiring sentients from consumption through raids by the Flayers or allied forces. In either case, it would ironically (and tragically for those living within) be one of the largest cities in the world. [Answer] The only thing evil people understand and respect is brutality, and they won't even respect that unless it follows rules. Otherwise they wouldn't be evil, if they were held back by principles, or empathy, or sympathy, they couldn't do the things that they do. So in this case, as per your setup, the most powerful entity is going to rule, but it cannot be by whim: There must be clear rules about what is allowed and what will get you killed in the most painful way possible for you, and they must magically enforce that penalty, even if it costs them more than they'd like, on every monster that violates the rules. I would add, even though you didn't ask, that if the Monsters cannot exercise their evil then they probably won't stay, and your city will eventually be abandoned. They aren't going to live in peace with each other just because it is a city! The value of a city is proximity and opportunity, usually at the hub of some kind of trade or attraction (e.g. movie studios, financials, shipping and trading, farm or ranch markets, etc.) For plausibility, I'd expect monsters to be there **for a reason,** to ply their evil trade perhaps, or live on the magic energy. The most probable rules to pass first are "don't damage the infrastructure," "don't steal from the shops", etc. Murdering and eating a pedestrian may be okay, but shoplifting gets you shredded alive, buster. [Answer] Real life examples abound, some of which endured 1000 years and more. In Polynesia it was done by basically terrorising anyone who broke the rules and executing their entire extended family if they got out of hand, or sometimes their whole region if it was a sub leader, in addition to making them cook up and serve their kids to the rulers at feasts during more peaceful times just to keep them in mind of who is boss. One king travelled in a canoe that was used on land and carried from place to place by conquered high chiefs to underline his absolute power. Yet overall the economy thrived, no one went hungry etc,. because control over leaders was tight and strictly enforced. People endured a lot before breaking the rules when the consequences are so bad. So you just need powerful, ruthless leaders. ]
[Question] [ In the early 21st century of a world closely resembling our own on the surface, rare individuals awaken Telekinesis- and Telepathy-based powers during adolescence. Their existence is unknown to the public through interference of certain organizations with power. One such government organization in a highly developed country, responsible only to the Ministry of Interior, employs superhumans to fight crime and terrorism in covert tasks. Nevertheless its actions and ways are not to be made public in any way. That being said, can the superhuman agents of such an organization be allowed everyday freedom when they are off mission? How can such an organization make sure that its agents will follow the rules of conduct at all times and will not jeopardize the faces of the organization, the government and even their superhuman fellows, should they stir trouble or even go rogue? If possible, the superhuman agents should actually feel their freedom(instead of, let's say, sleeping in homes under surveillance). It should also be taken in mind that many such agents are in their mid- or late-teen years because the side effects of said super-powers drastically shorten the user's lifespan(unbeknown to most of them though). That makes for even harder to control individuals. [Answer] The same way normal intelligence services operatives are. Train them, monitor them, enforce the restrictions. If your average CIA operative were announcing it to everyone they met and telling CIA secrets they wouldn't last long. You could also create specific areas (for example a remote village somewhere) where they are allowed to live and use their powers freely. If all else fails generating some sort of dampening device that blocks their powers and making them wear it would be an option. It would be a bit unfortunate if you lost a valuable operative to a mundane car crash while their powers were blocked though. [Answer] An important note is why they would give them everyday freedoms: presumably the superhumans want the freedom and their willing cooperation is important enough to force the organization to give it to them. This depends greatly on how amoral the organization is willing to be. If going rogue or needing to be terminated is a problem and the organization is willing to be evil then expect the kids to have secret little implants filled with poison hidden in their bodies that need to be reset every few months to prevent them from going off. Expect some serious brainwashing to keep them in line with anyone who doesn't respond well being terminated. Luckily these are kids/teens so add in simple pleasures to keep them happy. Sex, wealth, status etc. Paying people well can be a remarkably good way to maintain loyalty and keep morale up. There could even be an elaborate Truman-show style deception around their "normal" lives to ensure that they have an idyllic life, are only exposed to the "correct" ideals, to avoid release of confidential information when they inevitably tell someone and to make sure they have the perfect little girlfriend or boyfriend in their "real" lives to whom they can reveal their secret identity and who they think they're doing it all to protect. After all, we don't want them getting upset about their civilian lives and potentially becoming emotionally unstable. Better that the organization carefully control things from behind the scenes. Note that any Superhumans with telepathy or other powers which could reveal the deception would need to either be terminated immediately or be handled at another facility, never allowed near any senior organization personnel and handled through a layer of human personnel who sincerely believe whatever cover story is being used. Their limited lifespans makes some things easier, they only need to be controlled for a few years. They won't have decades to become disillusioned. [Answer] They have to get some freedom *on* a mission, or the mission gets a lot harder. If you can trust them during combat, why not during leisure hours? * Can you keep the low average lifespan secret from the operatives? Unless they are particularly dumb, they will notice the low number of older colleagues as soon as they learn college-level statistics. Any explanation they make up for themselves will be worse than the truth. * How many operatives, and how important is each? Can you assign a well-trained *team* to keep each one happy and under control? A father figure to offer counsel, a big brother figure to get into some carefully controlled mischief (nights out clubbing, etc.), a best friend who stays sober and becomes the designated driver? A boyfriend/girlfriend who is a few years older and very hot ... * Explain to them that all the benefits between missions depend on their value, which in turn depends on the secrecy. Once the masqerade is broken, they will be paid like a mid-level government official. No more sports cars, no more martinis in nice places. Accept that the secrecy won't be perfect and prepare to handle the fallout. Publish a third-rate superhero comic with the department names and callsigns of the operatives. [Answer] It's not all that different from a police force. Have a secret internal affairs department. Some of the super powers are telepathic, which to me means mind reading. So you have weekly "counselling" sessions where the members can can go and talk, share their frustrations, or just hang out and play board games. Doesn't really matter what they do, since the counselor will be carefully probing to see if there is any underlying resentment or other issues that need to be addressed in such a way as to diffuse the issue in a satisfactory way. Another thing that will help is a clear code of conduct that all members agree to, with clear routes to bring issues to light. One of the bigger things that the organization will need to think about are people that see injustice within the organization and decide to become whistle blowers. Having internal routes that actually work to fix internal problem will help stop this. [Answer] These super humans would not be granted the same freedoms as everyday people. Using the United States military as an example, you do face restrictions (and these for your average mechanic or what have you.) * Limited freedom of movement. All travel must be reviewed/approved. * Overseas "trips" to fun places like Afghanistan. These are not optional * Limited freedom of speech, no commenting on politics while in uniform (you're not supposed to at least) * Restrictions on appearance and fitness These are basic restrictions that all members of the US military accept. Considering the nature of your operatives and the likely exceptionally secret nature of their work they could expect increased restrictions on freedom of movement, speech etc. Operational lock downs are not uncommon. Leading up to a big mission they would generally have no communication with the outside world and would be on lockdown on the base somewhere. Considering their knowledge and abilities it would not be surprising to see significant observation/surveillance as well... An organization of specially trained people that get used/lied to/controlled by a secret government organization...always a good setting for a story. [Answer] Have your superhumans under secret surveillance at all times. Technically violation of their freedom. But as long as super humans don't know about they will feel free. Alternatively or additionally introduce informants into their daily lives such as a teacher classmate step-parent work colleague have them get close to the superhuman becoming there friend, romantic partner or trusted counselor. Then have your informant make daily reports bake to you on there action and mental state. This way if they are going rogue you can figure it out before hand. [Answer] > > Can the superhuman agents of such an organization be allowed everyday freedom when they are off mission? > > > Yes. > > How can such an organization make sure that its agents will follow the rules? > > > It depends on how strictly the rules are being enforced. Here are some approaches: * No enforcement: take it on good faith they will follow the rules * Incentives: e.g. money * Reactive enforcement: they break they rules and then they are punished * Surveillance: monitored so preventative measures may be taken * Selective recruitment: only bring on people who will abide by the rules * Training: taught to minimize their impact on the public * Indoctrination: fealty ingrained * Brainwashing: either with telepathy-based powers or some other means * Collateral: e.g. you have their loved ones * Ultimatum: e.g. an explosive in their head Options may vary based on the details of the particular powers. ]
[Question] [ Say you have a galaxy, possibly ours, with a central black hole. In an instant the black hole falls through a plot hole and vanishes. **What happens to the rest of the galaxy?** Does everything keep on like nothing happened? Does it slowly unravel? Does it quickly unravel? Something else? **Why this question?** In the Void Trilogy by Peter F. Hamilton, an artificial black hole at the center of the galaxy is suddenly removed. In the story, nothing much happens, and it seemed weird that no one seemed to think it was much of a big deal. [Answer] **Not all that much** Sagittarius A\* is big, but not that big. Its mass is estimated to be around 4,200,000 (four million two hundred thousand) solar masses. That's a lot of gravity! But consider the Milky way is estimated to be around 1,000,000,000,000 solar masses! In all, the total gravitational effects would be minimal. The largest effect would be on stars near the center (for whom most of the gravity from the Milky Way's stars cancel out rather equally, so they feel mostly the pull of the center). However, once you get a short distance away from the center of the galaxy, the effect of Sagittarius A\* herself is actually quite a small player in the grand scheme of things. Of course, you ask if anything unravels. Certainly physics just unraveled, right through your plot hole. Many years later, some intelligent species might notice that something funny happened. *EDIT: type\_outcast was kind enough to work through the numbers to see how fast a star would have to be orbiting to achieve escape velocity of the galaxy, initiating an "unraveling" like effect. He used the escape velocity equations, $v\_e=\sqrt{\frac{2GM}{r}}$, where M is the mass of the galaxy and r is the distance between the center of the galaxy and the escaping star. For a reasonable star, like S0-102, which is close enough to the center to be noticeably effected by the loss of nearby mass, that escape velocity was over half the speed of light! This means, unless the star is traveling at relativistic speeds already, it will not escape the galaxy. Thanks type\_outcast!* *EDIT: This questions is actually quite fascinating if you think about it. An entity labeled "super-massive black hole" vanishes from existence, and we hardly even notice because the galaxy is just that mind-numbingly big! I figure this might be a good chance to plug the [Universe Factory](https://medium.com/universe-factory), the WorldBuilding.SE blog, which has an article on [why it can be so hard to fathom these scales](https://medium.com/universe-factory/dealing-with-extreme-scales-c1540882bdb#.z2l13g2fx). It's worth a read, if I may say so myself!* [Answer] The answers so far have assumed that the galaxy in question is a spiral galaxy - and if we're talking about the Milky Way, then that's all well and good. But galaxies are pretty diverse, both in shape, size, mass and composition. Most look nothing like our own. It turns out that if you're willing to set your story in a different galaxy, you can get some pretty interesting effects from the removal of a large black hole. I'll look at the ratios between the mass of a certain black hole in a galaxy/star cluster and the mass of the galaxy itself: $M\_{\text{BH}}/M\_{\text{galaxy}}$. For reference purposes, the black hole at the center of the Milky Way, [Sagittarius A\*](https://en.wikipedia.org/wiki/Sagittarius_A*), has a mass of $\sim4\times10^6$ solar masses, while the Milky Way itself has a mass of $\sim1\times10^{12}$ solar masses, giving us $M\_{\text{BH}}/M\_{\text{galaxy}}\approx0.000004$. That's small; removing Sagittarius A\* from the Milky Way won't do squat. ## Globular clusters and intermediate-mass black holes [Globular clusters](https://en.wikipedia.org/wiki/Globular_cluster) are dense, gravitationally bound sets of stars, gas and other objects, usually of around . They're usually quite old - in the case of the Milky Way's globular clusters, as old as the galaxy itself. Now, what's interesting for our purposes is that there's not really a firm dividing line between certain globular clusters and [dwarf galaxies](https://en.wikipedia.org/wiki/Dwarf_galaxy), which may contain up to $\sim10^8$-$10^9$ solar masses. In fact, a few globular clusters, such as [Mayall II](https://en.wikipedia.org/wiki/Mayall_II) and [Omega Centauri](https://en.wikipedia.org/wiki/Omega_Centauri), may contain [*intermediate-mass black holes*](https://en.wikipedia.org/wiki/Intermediate-mass_black_hole), a putative class of objects with masses of up to $\sim10^6$ solar masses.1 In the case of Omega Centauri - where the existence of the black hole is disputed - the maximum mass is $\sim10^4$ solar masses. The mass of the globular cluster itself is $\sim4\times10^6$ solar masses, meaning $M\_{\text{BH}}/M\_{\text{galaxy}}\approx0.0025$. Mayall II gives a ratio that's roughly the same, maybe a bit lower. If the black hole in one of these two globular clusters was removed, it would influence the orbits of the innermost stars. This is perhaps more dramatic than in the case of a normal galaxy, because globular clusters have density distributions strongly peaked towards the center. In other words, yes, many orbits would be disrupted, although I doubt that it would be enough to disrupt the cluster. Remember, the mass ratio is still less than 1%. ## Massive elliptical galaxies Some supermassive black holes have masses on the order of $\sim10^9$ to $10^{10}$ (1 billion to 10 billion) solar masses, three of four orders of magnitude greater than Sagittarius A\*. These black holes yield much better mass ratios than smaller supermassive black holes. One issue, unfortunately, is that some of these ultra-high mass supermassive black holes are found in very massive elliptical galaxies, which can be up to several trillion solar masses in size. Consider [NGC 1600](https://en.wikipedia.org/wiki/NGC_1600). Its central supermassive black hole likely has a mass of $\sim2\times10^{10}$ solar masses, while the galaxy itself has a mass of $\sim10^{12}$ solar masses. That's not bad; we get a mass ratio of $M\_{\text{BH}}/M\_{\text{galaxy}}\approx0.02$. [NGC 4889](https://en.wikipedia.org/wiki/NGC_4889), a supergiant elliptical, has a central black hole of similar mass; its total mass is $\sim10^{13}$ solar masses, yielding $M\_{\text{BH}}/M\_{\text{galaxy}}\approx0.002$ - possibly smaller, if non-luminous matter exists there in large quantities. ## Dwarf galaxies and supermassive black holes Omega Centauri (and certain other high-mass globular clusters) may be the cores of dwarf galaxies, stripped apart by tidal forces from the Milky Way. As I said before, the dividing line doesn't really exist. However, a high-mass dwarf galaxy is certainly different from a low-mass globular cluster. Now, consider a set of dwarf galaxies called [*ultra-compact dwarfs*](https://en.wikipedia.org/wiki/Dwarf_galaxy#Ultra-compact_dwarfs) (UCDs). Their masses are on the order of $\sim10^8$ solar masses. One UCD that particularly excites me is [M60-UCD1](https://en.wikipedia.org/wiki/M60-UCD1). This galaxy has a mass of $\sim10^8$ solar masses, and **might house a supermassive black hole of $\sim2\times10^{7}$ solar masses** - five times the mass of Sagittarius A\*! This leads to a mass ratio of $\sim0.15$, which is enormous! The orbits of many stars in the galaxy - which is only about 200 light-years across - are quite strongly influenced by the black hole. Removing it would certainly disrupt a number of orbits. There ultra-compact dwarf population continues to grow, as does the population of supermassive black holes in UCDs. It was recently announced that UCD-3, [a galaxy with a mass of $\sim9\times10^7M\_{\odot}$](https://www.aanda.org/articles/aa/pdf/2007/07/aa6429-06.pdf), likely contains [a black hole of $3.5\times10^6M\_{\odot}$](https://arxiv.org/abs/1804.02938), giving us $M\_{\text{BH}}/M\_{\text{galaxy}}=0.038$. This is lower than M60-UCD1 by a factor of four, but that's not much, and it's quite encouraging. I will say that I don't think you can get any better than this. Compared to the Milky Way, M60-UCD1 is an *excellent* candidate for this sort of setting. It's also extremely dense, and quite massive for an ultra-compact dwarf. The high density means that, just like in a globular cluster, you can probably find plenty of exotic objects inside, from [blue stragglers](https://en.wikipedia.org/wiki/Blue_straggler) to [Thorne-Żytkow objects](https://en.wikipedia.org/wiki/Thorne%E2%80%93%C5%BBytkow_object). --- 1 As of July 2018, no intermediate-mass black holes have been confirmed, but there are a number of candidates: * The possible black holes at the centers of the globular clusters [47 Tucanae](https://en.wikipedia.org/wiki/47_Tucanae), [Mayall II](https://en.wikipedia.org/wiki/Mayall_II) and [Omega Centauri](https://en.wikipedia.org/wiki/Omega_Centauri#Evidence_of_a_central_black_hole) (all disputed) * The central black hole in the spiral galaxy [NGC 4395](https://en.wikipedia.org/wiki/NGC_4395) * Possible black holes in [Messier 82](https://en.wikipedia.org/wiki/Messier_82) ([Messier 82 X-1](https://en.wikipedia.org/wiki/M82_X-1)), [Messier 74](https://en.wikipedia.org/wiki/Messier_74), and ESO 243-49 ([HLX-1](https://en.wikipedia.org/wiki/HLX-1)) * The central object in the star cluster [GCIRS 13E](https://en.wikipedia.org/wiki/GCIRS_13E) * An object in the high-velocity cloud [CO-0.40-0.22](https://en.wikipedia.org/wiki/CO-0.40-0.22) * A number of other [ultraluminous X-ray sources](https://en.wikipedia.org/wiki/Ultraluminous_X-ray_source) (ULXs) If some of these exist, they could be reasonable decent choices for you. Also, [a recent search of *Chandra* data](https://www.nasa.gov/mission_pages/chandra/images/cosmos-legacy-survey-shows-evidence-of-intermediate-mass-black-holes.html) indicates that there may be a substantial population. I'll update this list if any of these are verified in the future. [Answer] Everything's relative. If the force pulling the stars to the center ceases, the stars' orbit velocity will shoot them out from the center in a straight line (obviously - there are no circular forces) but not perpendicular to the center. If you think it does this slowly, well, the Sun is travelling at 720.000kmh. That's fast. Relatively speaking. And the closer to the center, the highest the speed. [Answer] A flippant answer. Every gravitational wave detector on earth would glitch off the scale and a lot of physicists would be thinking "WTF now??". At least until they compared notes with other gravity wave detectors and with the astronomers. The rest of the world would first not notice and then not care a jot. Setting this event in Vinge's zones of thought universe would be interesting. ]
[Question] [ I have this fictional sci-fi galaxy (similar to Mass Effect) in which a race of aliens is blind, but has superhuman hearing. I want to make these aliens interesting and somewhat scary on the battlefield, so the first thing I thought of was a sound gun. That is, a weapon that fires a directed beam of sound at a target. The original plan was that they could use the harmonic frequency of the human brain to blow up people's heads, but at this point I'd be happy if they could use it simply to stun or disorient foes. The main problem I'm dealing with is that I don't think sound can be fired in a beam like light can. From experience, sound tends to be omni-directional or spreads out almost immediately. However, I know my knowledge of science is lacking, so I was hoping I could come here for some definitive answers. So, in summary, **can there exist a weapon that fires a directed beam of sound?** How might it work, or if it's not possible, how might a similar sort of weapon work to get somewhat loud results? You shouldn't be affected by the sound as it goes past, at least not as much as you would if you were in its path. I'd be hoping for the ability to temporarily or permanently deafen foes with such a weapon, but a smaller effect that can be scaled up is fine. As this is a sci-fi setting, there is a lot of room for technology and power, but I would like something that's based in real science. [Answer] ## **Ultrasonic Gun** It's well known that with the correct frequency applied that sound, and sound alone can shatter a wine glass. These demonstrations are always spectacular, so let's build a weapon on the same principle. **Assumptions** Since we are working with sound, above a certain threshold, a sound wave will just pulverize the target. The CDC lists [10psi of overpressure](http://www.cdc.gov/niosh/docket/archive/pdfs/NIOSH-125/125-ExplosionsandRefugeChambers.pdf) as > > Most people are killed > > > so let's use that as our upper bound for power requirements for this weapon since we want to liquify the person, not instantly pulverize them. Further, we assume that we can overcome the high natural elasticity of skin to cause it to liquify. **Safety Concerns** The OP states that this will be human mounted weapon so safety precautions need to be made to ensure the weapon carrier doesn't get liquified too. While ultrasound is still sound, it is "aim-able" in that pointing the ultrasonic transducer sends sound in that direction and not anywhere else. As long as the weapon bearer isn't "looking down the barrel" then they should be okay. **Power Requirements** The 10psi overpressure threshold set out in the Assumption section is 700 times the [limits of human hearing](https://en.wikipedia.org/wiki/Orders_of_magnitude_(pressure)) (130db). Speakers that generate 110db of sound often require thousands of watts. Granted, the energy from normal speakers is spread across a much wider area than an ultrasonic transducer would but I think that sets a decent lower bound on the power requirements for this this weapon. Given that also don't know the power requirements to achieve destructive resonance in human tissues, the power supply may be asked to provide megawatts of power but since we don't know how much power it takes to liquify human flesh, let's just hand-wave and call it good. Regular speakers just don't have the [power output required](http://www.therichest.com/business/technology/the-10-loudest-speakers-and-subwoofers-in-the-world/) or the directionality that we want, so let's go with ultrasonic transducers. Let us assume that a megawatt class ultrasonic transducer can be created and matched to adequate heat dissipation tech. **Frequency Requirements** There is [no one frequency](http://www.ncbi.nlm.nih.gov/pubmed/8176050) that the human body resonates at, or perhaps there is but the power requirements to do so amount to getting hit by the blast wave of high explosives. At a minimum, you only need to know two frequencies: muscle and skin to count as "liquifying the target". Muscle alone will just make the target fallover. Skin alone just make the target look naked. This leaves the horrifying prospect that the brain are still intact but the target's body is liquifying. If the nerve endings are still functional then.....Death shortly follows but looking down to watch your body turning to liquid.....that's nightmare fuel. Killing someone may not be as effective as just maiming them by liquifying their skin. Wounded soldiers take significantly more resources to treat/transport than a dead soldier. **Time for Effect** I have no numbers but I think the effects would happen very quickly, just a few seconds. This makes it an effective battlefield weapon because you can't expect a target to stay still for a minute or so. **Weapon Design** Since an ultrasonic transducer by definition emits sound at greater than 20Khz, we will need a second transducer to use interference to generate the target frequency. Both transducers can be fitted to a gun-like mount linked to the power supply backpack. Heat dissipation from the power source and the transducers will be important considerations. Add a control to allow the weapon carrier to select a target frequency with some presets for skin, bone, etc. However, access to the raw frequency permits the carrier to experiment with finding the frequency for stone or metal. [Answer] *Sound guns*; also known as [Long Range Acoustic Devices (LRAD)](https://en.wikipedia.org/wiki/Long_Range_Acoustic_Device) in the US military; exist, were developed by the military, weaponized, and deployed several years ago (circa 2005). These weapons project a highly directional sound beam and have been used to "discourage" Somali Pirates when they attack cruise ships. LRAD: [![LRAD](https://i.stack.imgur.com/alZ0x.jpg)](https://i.stack.imgur.com/alZ0x.jpg) > > According to the manufacturer's specifications, the systems weigh from > 15 to 320 pounds (6.8 to 145.1 kg) and can emit sound in a 30°- 60° > beam at 2.5 kHz. > > > and some technical information about sound directivity: > > The parameter "ka", which is the wave number multiplied by the speaker > radius, is often used to characterize sound source directivity. For > this source, ka=19 at 2.5 kHz, and according to the LRAD data sheet, > the beam angle of about 30 degrees total is precisely what is > predicted for a regular loudspeaker.] > > > Small spherical "point-source" acoustic devices follow the known > inverse square law, which predicts the loss of 6 dB per doubling of > distance from the source, solely due to geometric spreading. Large > speakers (or large arrays), such as these, have an interference > pattern in the nearfield which produces peaks 6 dB higher than the > output pressure and nulls where the pressure is essentially zero.[5] > The larger the speaker, and the higher the frequency, the longer the > effective nearfield. The nearfield for this device is approximately > 8m. > > > [Answer] **1.** The [Vortex Cannon](https://www.youtube.com/watch?v=IN_N_J1yx-U) is absolutely possible. It just needs refinement. [![enter image description here](https://i.stack.imgur.com/d3uRD.png)](https://i.stack.imgur.com/d3uRD.png) --- **2.** Additionally you might be interested in Kate Bush - Experiment IV No technical details are shown but the idea is there. (Not suitable for nervous children!) [Kate Bush - Experiment IV](https://www.youtube.com/watch?v=NTUcoR8_pyE) [![enter image description here](https://i.stack.imgur.com/CjqDH.png)](https://i.stack.imgur.com/CjqDH.png) Song lyrics: > > We were working secretly > > For the military > > Our experiment in sound > Was nearly ready to begin ... > > > They told us, all they wanted > > Was a sound that could kill someone > From a distance > > > --- **3.** The idea of focusing sound has already been tackled here. [How can you focus sound?](https://physics.stackexchange.com/questions/1263/how-can-you-focus-sound) [![enter image description here](https://i.stack.imgur.com/j8I1S.png)](https://i.stack.imgur.com/j8I1S.png) [Answer] Parabolic dishes can be used to focus sound waves. With a pair of parabolic dishes facing each other, people are able to talk at more than 100m distance without straining. This is sometimes seen in childrens' play areas. The gun in chasly's excellent answer burns 100L of air with the corresponding amount of acetylene: that's about 20L of oxygen and 10L of acetylene: about 60g of explosive material. I think a suitably reinforced 2-3 metre dish with 1kg of solid explosive at its focus would make a less bulky and probably more effective weapon. Admittedly, i've never built one. ]
[Question] [ In my setting, I have reasonably traditional Dwarves and Elves. The Dwarves magic allows them to control metals, earth, and other non living constructs. The Elves can control non sentient living things like plants and animals. In the past, during a Dwarf-Elf war the dwarves turned the elves metal armor and weapons against them. Now the elves refuse to use any metals at all. What options do they have for armor and weapons that can rival dwarven steel? I would like answers for each of the following criteria based on the elven beliefs and magical abilities to get the most useful armor and weapons: 1. Use only natural, living components with no modifications but magic to keep the plants or trees alive. 2. Use animal components such as horns, tusks, teeth, spider silk, or skin in addition to the plants above. 3. Use basic magical manipulation to change the chemical and physical structure of plant and animal based substances to produce a new one, such as carbon fiber. Bonus question: my elves also don't like fire. Bioluminescence can replace light from fire, but what process could generate enough heat for the elves to survive the cold that doesn't threaten to consume whole forests? (Another bad experience in a previous war.) [Answer] I'd much rather fight by controlling nature. *Nature's a bitch, man.* **Defending** Healing armor. Active defense. There are lots of options for armoring using natural materials. Leather, chiton, or fibers. A mix of the three can provide fairly excellent protection against certain attacks. If they use living armor it can even *heal* or provide *active* defence. Yes, that elf's armor just swatted a blade aside and that one just inflated a gas bag to absorb a hammer blow. **Attacking** Disease. Poison. Toxic fungus spore gas. Swarms of bees. Mice infiltrators. The greatest benefit is what the Elves have to attack with. Namely, disease. Biological warfare doesn't care how heavy dwarven armor is. They can use toxic mushroom spore grenades. It's almost unfair. A swarm of bees should be able to find openings in the armor. Herds of mice to chew straps. [Metal-eating bacteria](https://en.wikipedia.org/wiki/Microbial_corrosion). Basically, nature is trying to kill all of us anyway, put an intelligent will behind that force and it's something to be reckoned with. Elves win. Game over. **Staying warm** At the party afterward they can stay warm by standing around large pile of metal being eaten by bacteria. The oxidation occurring is an exothermic reaction; it puts off heat. But not much in reality, they'll be better off building large compost piles (they can get up to 135°-160°F). [Answer] For both armor and for weapons, metals are a fantastic choice. They offer hardness and ductility that are hard to obtain in other materials. There are, however, a few other choices worth looking at. ### Armor **Leather** Leather armor, sometimes reinforced by [boiling it in water or oil,](http://en.wikipedia.org/wiki/Boiled_leather) makes an effective armor. It's less effective than steel, but also cheaper. **Wood** Wood is stiff and clunky, but was [used by the ancient Siberians](http://en.wikipedia.org/wiki/Indigenous_peoples_of_Siberia) to build armor out of. Specifically, wooden pauldrons were used in addition to suits of lamellar armor made from boiled seal skin. **Paper** Armor can also be made from sheets of paper laquered together. This was used by the ancient Chinese as a form of armor, and was quite effective. It's cheaper to make than steel armor, but breaks down over time. [It's had some minor implementation in the modern day, as well.](http://mythbustersresults.com/paper-armor) ### Weapons **Ceramic** Ceramic is harder than steel. However, it's also quite brittle. It makes for some extremely sharp knives and tools, but swords, for the most part, are made to survive hard knocks. There is, however, an exception to that general rule that is quite common in fantasy settings: [the katana](http://en.wikipedia.org/wiki/Katana). The Japanese didn't develop smithing to the same degree as the Europeans, so they relied on the process of folding somewhat weaker steel in order to produce a sharp blade. This produced a blade that was stiff and excellent for cutting, but would shatter if used incorrectly. Because of this, a level of mastery was needed with a katana before it could be used for war. Ceramic offers some similar properties to the steel used in katanas. It's incredibly hard, but also brittle. Your elves could use blades with ceramic edges in a similar way that the katana was used. The focus would be on a single, powerful killing blow, with little to no sword to sword contact or parrying, which would chip or shatter the blade. Properly struck, such a blow would allow a ceramic blade to slice through metal armor more easily than a steel sword. Long ceramic blades would be tough to make, and even tougher to make strong, so it's likely that either something more like an ax would be used, or else that a sword blade would be made from multiple, overlapping ceramic blades. **Wood, bone, and carbon fiber** Wood, bone, and carbon fiber could be used to make weapons, but don't hold an edge well. They do, however, have the advantage of resiliency over something like ceramics. They bend without breaking, making them better for something like a handle or the shaft of a spear. For a sword, carbon fiber could be used for everything but the edge, which could be made of a stronger material like a ceramic. **Other natural materials** On Earth, other natural materials with the hardness and strength to be excellent weapons, easily on par with steel, do exist. Unfortunately, they don't come in large quantities, generally found in tiny structures like the [teeth of limpets,](http://www.theguardian.com/science/2015/feb/18/limpet-teeth-strongest-natural-material) which are made from a composite stronger than anything we've ever made in a lab. The claws or teeth of dragons, in your world, could be made of such a material. If they were, the elves could use this as their main material for weapons, making elven blades rare, but the sharpest and strongest in the world. [Answer] First of all, they should avoid any close encounters. No stone or wooden weapon and armour can stand against a dude in a full plate armour. Indeed, that is why full plate armours were invented in the first place. But your setting is perfect for hit-and-run tactics. Elven army approaches enemy like ghost, uses surprise to their advantage and disappears before dwarves realize what happened. In this case, any armour is for elves more of a liability than advantage, because it slows them down and makes it harder to sneak up on the enemy. Traditional elven bows and arrows are perfect for this tactic. They are silent and easy to carry. You can use bones or special wood for arrowheads, as long as you wait with your attack until the enemy takes off his armour. And if he doesn't take it of for a long time (like a couple of days) it will take a toll his body anyway and do the job for you. Now as for mounts, I suggest unicorns, because... why not? But normal horses will do as well. They were already used for guerrilla warfare in our world: <http://en.wikipedia.org/wiki/Lisowczycy> <http://en.wikipedia.org/wiki/Henryk_Dobrza%C5%84ski> You can throw in some ink-spitting, fog-creating, poison-dart attributes to the mounts, to make them more useful in ranged combat. If they control plants, they can also use toxic spores as a weapon of mass destruction. And as for bonus question, how about hot springs? No fire involved. It's not a new idea as well: ![enter image description here](https://i.stack.imgur.com/ABMRe.jpg) [Answer] Quite a few options. For instance, Mongol-style composite bows. The elven archers would of course have to be good enough to hit vision slits or gaps in the dwarven armor, but that skill level kinda goes with being an elf, doesn't it? For close combat, see the Aztec Macuahuitl <https://en.wikipedia.org/wiki/Macuahuitl> Then there's the quarterstaff (and Asian variations): get your armored dwarf on the ground, and he's toast. You might also look at the Roman retiarius <https://en.wikipedia.org/wiki/Retiarius> Then there are also various area-effect weapons, such as catapults throwing stone balls. [Answer] One material you should consider is **glass**. Glass is very strong, easy to work, and quite magikable. While brittle in comparison to steel, it too can be heat-treated to make it stronger and more flexible. Glass is impervious to corrosion, can be made from very common materials (mostly just sand with a few additives), and can be worked into a viciously sharp edge. This was what was used in *Treason*, by Orson Scott Card. In the book, there is a planet named Treason which has no natural deposits of iron or other hard metals, on which the galactic civilization marooned a group of rebel intellectuals trying to overthrow them a few hundred years ago. The only way they could get iron is to sell things off the planet. Because iron is so scarce, most weapons and tools are instead made out of glass. Armor could also, in theory, be made out of glass, but since their armor would be intended to resist the heavy bludgeoning weapons typical of most sorts of dwarves, it would be more likely that they would use some type of laminated wood and horn. More important than the surface armor, though, is the type of padding under it, which usually is made from wool, leather, or whatever other material is typically used. [Answer] Only magic is going to allow you to put a tooth on a stick through steel armor. Once you are hand-waving *magic makes it so*, do whatever you want. Leather or layers of cloth can make good armor - not as good as steel for most applications, but suitable enough to have been popular historically. A thick coat of layers of silk cloth laminated or quilted together would be fantastic protection. You will be unable to find anything living which could possibly rival steel for making weapons. You could possibly use a massive tooth on a long pole as a sort of warhammer - some species have pretty strong tooth enamel (the hardest substance anything grows). This could knock a dwarf down, but is still unlikely to harm the dwarf inside and would still be quite prone to breaking against the steel plate. Individual dwarfs could be brought down with bludgeons and then thin bone/antler knives used to find the gaps in the armor (there are always eye slits even if joints are well protected by mail). Unfortunately a dwarf in plate is going to be proof against anything an elf can wield - a small group of dwarfs could be overwhelmed, but no grand melee is going to go well for the elves. As far as keeping warm in the winter, that is easy - good clothing. [Answer] Use magic to manipulate living (or former) living objects by transformation of [Carbon Allotropes](http://en.wikipedia.org/wiki/Allotropes_of_carbon). Carbon is the building-block of most known life, and its allotropes can have incredibly properties. A very simple example would be diamond-edged swords, knives, and arrowheads. You don't want to make an entire weapon out of diamond - it would be incredibly brittle and would break easily - but you can use diamond to enhance the edge and cutting power. So yes, that wooden sword suddenly can cut through armor, and bows Pure [Lonsdaleite](http://en.wikipedia.org/wiki/Lonsdaleite), while not something we can form (or that occurs in nature), is even harder than diamond and could be used in it's place for even better weaponry. [Carbon Nanotubes](http://en.wikipedia.org/wiki/Carbon_nanotube#Properties) have a ridiculous strength for their weight, and could be used to create razor-thin wires or bolas that would cut enemies up instead of just tripping them. They likely could also be used to create incredibly strong bow strings, or for structural building. I'm sure there are other possibilities as well, although it depends on what kind of non-magic tech level you want. Note: I don't expect that magical elves would necessarily use the science jargon above, but they're not dumb and might have stumbled on many of these options by accident while experimenting with life magic. [Answer] I'm not sure how much or what kind of magic your elves have, so I will try to keep magic use to a minimum. I will assume that they can make plants and animals grow more than they do on Earth, so that the best materials won't be exceedingly rare. For armor, leather has already been mentioned. That is because it makes a good armor. It is both tough and flexible, and it is made from animal skin processed with plant and animal products. If it gets wet, it can become harder and stiffer, making boiled leather especially useful for armor. The leather-like material rawhide is even harder, but is can also be brittle. Wood is not the best option if you stick to common woods like oak or maple. However, there are rare woods that are more than three times harder than hickory, the hardest "common" wood, such as [this](http://en.wikipedia.org/wiki/Allocasuarina_luehmannii) Australian bull-oak. Woods like this could stand up to steel, at least for a little while. Many different types are commonly called "ironwood". As for weapons, you could look at "primitive" cultures where metal was not readily available, like in the Americas, Africa, or Oceana. Many weapons from these areas took the form of clubs, like the Zulu [knobkierie](http://en.wikipedia.org/wiki/Knobkierie), the Māori [patu](http://en.wikipedia.org/wiki/Patu), or the Aztec [macana](http://en.wikipedia.org/wiki/Macana). Clubs are still useful weapons against plate armor—in medieval Europe, many units used maces, hammers, or similar weapons against armored foes. If made using the same hardwoods mentioned above, the elves could be quite effective. Also, note that many of these club-like weapons had cutting edges, even if they weren't sharp enough to be considered blades. Fangs or horns could also be added for penetrating power, like the Aztecs used obsidian. Depending on the degree of physical manipulation that the elves can perform, they could use the carbon present in all living things to create diamonds or carbon nanotubes. Using nanofibers to reinforce their armor and having diamond-edged weapons would probably let them outdo the dwarves. As for keeping warm during winter, using wool and fur for clothing would help a lot. As for their homes and cities, there is a simple solution: [thermogenic plants](http://en.wikipedia.org/wiki/Thermogenic_plants). If you have plants that generate heat, why do you need fire? [Answer] The biggest downside of an 'all natural' approach is hardness and sharpness. Few things occurring naturally will be as hard as a decent steel, nor do many things take a sharp edge. Flint and obsidian for example (although you omit them from your original post) become extremely important for that reason - they're sharp. I would suggest that what you'll have is a skirmishers vs. heavy shock troops sort of battle. An archer simply cannot go toe to toe with a knight - they'll lose. And plate armour will fairly reliably stop arrows. But I don't think it'd take much scaling up in your fantasy world to make bows that *will* pierce armour. The 'classic' English longbow was up to a draw weight of 180lb. <http://en.wikipedia.org/wiki/English_longbow> But with modern techniques - you get compound bows, which provide a multiplicative effect. <http://en.wikipedia.org/wiki/Compound_bow> I don't think it's too much of a stretch to allow your elven archers some really quite horrific poundages on their bows. Similarly - crossbows. You can gain some seriously large mechanical advantage on crossbows/arbalests. The downside of crossbows though is that metal tends to be a key factor - I don't think you'd be able to make an all-wood crossbow with the 900lb draw like this one: <http://www.todsstuff.co.uk/crossbows/windlass-crossbows.htm> But maybe you could use similar techniques as you would with a longbow. Inevitably you'l end up with a longer arm, but ... well, ballista or scorpions were primarily non-metal. <http://en.wikipedia.org/wiki/Ballista> The other enemy of the armoured warrior is the pole arm. Bills were the starting point - little more than a farming tool. <http://en.wikipedia.org/wiki/Billhook> But with a 6ft pole, fighting in formation - the armour advantage reduces, because you've got the ability to poke them in lots of places at once, and hook, trip and stab. Armour is good, but when you're on the floor, finding a 'vital spot' and finishing you off becomes *MUCH* easier. So I think even without the addition of magic into the mix, you've go two races that'll be at a bit of a stalemate. Armoured dwarves will be nearly invincible in close combat, but hampered by terrain, ranged attacks and general mobility. (Mobility in plate is a lot better than you think, but if you assume equal levels of fitness - the guy who isn't carrying the weight is going to be able to do more). You don't diminsh that too much if you allow early firearms (muskets, flintlocks etc.). They're damaging, but their range and accuracy is poor. And then you get Elves who are able to take good advantage of rough terrain and ranged attack. Fighting mobile, with bows that are *potentially* very dangerous if you allow the modern style compound bows with proper sharp flint/obsidian arrow heads. They're wearing light armour and are generally a lot more mobile and able to make use of cover. Thus the stalemate - in the rough ground (forests) elves win. In the open ground, dwarves win. And so they'd be foolish to fight off their favoured ground. That's before you add magic to the mix - which I think logically would have to be aimed at playing to strengths. Fast plant growth to create the rough ground that the Elves can exploit. [Answer] The weapons/armor question seems well answered, so I'm looking at the "stay warm" question. First, if the elves have affinity for natural magics and can wear living armor, why can't they just wear furry clothing that is alive- and generating heat? They would have the equivalent to heated coats without the drawback of heavy batteries or short-lived chemical reactions. Second, depending on how widespread magic is among your elves, they can simply enchant themselves to be cold resistant. This could take many forms, from simply saying they cast a spell and aren't bothered by the cold, to something more akin to eastern [monks controlling their internal body temperature](https://www.buzzworthy.com/monks-raise-body-temperature/) (except with magic). [Answer] A spider silk resin composite armour would give Dwarven steel a run for it's money Scientists are currently developing [spider silk](https://www.livescience.com/46519-spider-silk-bulletproof-clothing.html) armour for soldiers. The real key is the difference in fighting styles. The Dwarfs would be better armoured and geared up for mostly hand to hand combat but the elves would be archers and highly maneuverable. The dwarves would most like win, not due to weapons but the fact they can set the whole forest on fire and burn the elves out. [Answer] Natural Weapons and Asymmetric Warfare **Rope** The spring tree noose trap has been used for centuries to trap small game. If an elf can control the natural fiber, then he can put the noose around a neck instead of a leg. The first defense is for the Dwarf to wear armor for the neck, aka gorget. The next level is to have two spring traps, one for each leg of the dwarf and pull him apart. Armor isn't designed to prevent this. It could be, but it may make the armor so stiff and heavy than the dwarf is immobile. **Wood** If the elves can control plants magically, then the crossbow becomes an awesome weapon. The crossbow limbs could change stiffness on command. In relaxed state the bow would have a draw strength of 50 pounds for quick loading. Once cocked the elf puts his magic into the crossbow to have a draw strength of 500 pounds and fires. **Bamboo** I believe that it was used to make many booby traps in Vietnam. It is rather hard and can dull an edge. **Food** How long can a dwarf army fight when their rations spoil? If the elves are masters of natural things, then convince the bees and wild game to leave the realms of the dwarves. Next have the domesticated animals stop producing milk and offspring. Crop failures, potato blight, corm smut, etc... **Ophiocordyceps unilateralis** Yes, the zombie fungus that takes over the minds of ants. A little elf magic and you have fungal induced zombie dwarves. ]
[Question] [ In my story, some personal effects get jettisoned from a spacecraft airlock. Some time later (months to years), other characters discover one of these items drifting in space. It holds information on it, but I'm not sure what format to use. I'm sure the obvious answer is an SSD or some form of flash storage, but there are reasons in the story for the technology to be outdated. I initially wanted to use a VHS tape, but I don't know if the tape would degrade in the cold vacuum of space and/or with direct exposure to the sun. I'm sure text on paper would get bleached, but what if it was a notebook or folder that remained closed? Would a floppy disk or CD-ROM have any issues, or are all forms of digital storage equally fine in this scenario? Is this a silly question? Thanks in advance! Edit: To be as specific as possible, I'm looking for the most viable form(s) of data storage, in widespread public use pre-2010, that would survive approximately one year orbiting the Earth at about 200,000 km/125,000 mi. [Answer] **Paper should survive** There is not enough debris in space to *consistently* do damage over a year to exposed surfaces, so I assume that books, letters and the like should retain integrity. So your discoverers would at least discern information from anything written in a book or letter, provided it was *etched*, regardless of ink state. Etching is caused normally while writing with a ball point pen, as the process of ink transfer involves pressure to spin the ball while the pen slides over the paper. While the paint might mot survive the exposure due to sublimation or other reasons, the etching is not undone as quickly. Any debris hits would just make holes or splats, making a bit of text lost or unreadable, yet the whole might provide enough context to restore the missing letters. **Inks have troubles, but a year is not too long for them to completely degrade** The issues might hit anything printed, as both typographical print and laser print makes bits of paint adhere to surfaces rather than get embedded in them, making bits of paint less resistant to heat/cold strain and charged particles as a general exposure. Laser paint (toner) tends to get peeled off the sheets even on Earth over several years, even if the media was protected most of the time, in space this should worsen to a possibility of blotched space appearing all over a laser-printed media. Not sure if that media would stop being legible after just a single year, but give it ten, and it'll get almost blank. Jet printed media resists heat/cold better but it might sublimate off the exposed media into vacuum, if the components of a paint were volatile enough, however that paint would leave traces in the paper for the researchers to still be able to discern the writings after several years of exposure. So count jet prints as legible with special measures. **CDs would likely break apart, and get numerous read errors** Unless the CDFS format used in your universe allows for ECC everywhere, the data on an exposed CD-R/CD-RW might be counted as lost, however large parts of it could still be read in fragments (sectors) containing one to several dozen actual bit errors. This is due to the data layer of a CD-R/W being exposed to high-energy sunlight (UV and above) and charged particles which deteriorate the state of sensitive material used to store the data. Sunlight intensity is hard enough to penetrate plastics, and anyway data writing to a CD-R/W is done with a laser of visible light (early, DVDs IIRC have an UV laser, anyway too low energy to not get erased by exposure), so the sunlight could just write random data over what was on the CD-R/W. CD-ROMs are made differently, the data is contained in bits of metal embedded in plastics instead of in a contiguous layer of something, so each individual bit has far greater chance of survival under the sunlight. Yet there is a debris problem, a CD-ROM hit by a piece of dust at cosmic speeds has a high chance to split in half, or produce a crack in plastics that would result in it breaking apart when spun up for reading. However, since you're speaking about personal data, CD-ROMs are out of scope, as a person is not able to produce CD-ROMs on their own. So, while a CD-ROM stored in the stuff might actually survive (with probability), its contents would not belong to a person whose stuff that originally was. **SSD and Flash would lose data quickly enough** In fact SSDs are best to not get exposed to sunlight even on Earth, with UV shielding and stuff, as data on an SSD is stored in pockets holding electric charge, and any possibility of excitation causes charge leaking, resulting in different charge level at read, thus different bit sets (hello TLC+QLC!), this damage would also make the SSD controller to fail by losing its operational data (there's a ton, not going into details). Flash NAND memory also stores charge in form of triggers' state, leaking that charge is also pretty expected from charged particles and ionizing photons. **HDD might also not survive, but the data is protected better** The 2010s HDDs used quite small magnetic domains as means to store data, and some older but still working drives even did not have extra Flash NAND onboard storage for controller data (instead it was read from tracks off the working range at drive startup), and controller ROM was usually wired. Also external hard drives are normally boxed in, offering additional protection to exposed electronics. A year in space would cause air in a HDD to leak away, but some precautions taken after the HDD is retrieved (and in case of an old enough device, its controller board replaced to increase chances of it starting up normally) could let your discoverers delve into the decently vast personal storage of downloaded memes and Temporary Internet Files. The HDDs are built with a metallic case that actually gives the data layer excellent protection from hazards in the near space, up to and including charged particles. In case a HDD is hit by dust, a too small bit would not even dent the cover, a too big bit would blow a hole through the cover and probably several disk plates out of how many installed (say a 18-TB hard drive of current manufacture has 9 plates, an old 4-TB SAS server-grade drive had two or four depending on the manufacturer, 2.5" HDDs usually have one, and should they have a [IBM-2311](https://www.computerhistory.org/revolution/mainframe-computers/7/161/569) or similar device for their PC among their belongings (plate wise), it might only leave a dent worth several kilobytes even not preventing the device from working normally. That is, the older is the HDD, the easier it would be to get the data off it after space exposure, provided they are able to get spare parts for it. But even an average HDD of 2010s should remain perfectly readable in a clean room with tools, with about 99% of data being intact, even after several actual debris collisions. If it was boxed, and the box isn't penetrated, there is a decent chance that it'll just start up normally after being exposed to atmosphere for a day, to fill the insides through a breather hole. **Flexible media would suffer down to unreadability** The reason is that flexible media is made of polymers which are prone to deterioration under sunlight exposure, the stronger the harder. The good thing for tapes is that they are folded over a spindle at least hundredfold, so should the tape in question be retrieved quickly enough, and be initially rewound to start, the inner (close to tape end) parts of the tape might retain integrity. Still, the tape in itself would be unusable by an ordinary person, and would require special tools to be read. The good thing is that VHS tapes are analog signal, so any bit rot involved would not destroy the data. Flexible disks aka floppies would likely suffer the same fate as the exposed or close-to-exposed areas of tape, aka crumple up destroying data stored on them. The 3.5" floppy is actually boxed, alowing it to get exposed for longer while retaining usability (reading should anyway be done raw, but floppies have large magnetic domains compared to HDDs so a lot harder to lose data to exposure, if not for the underlying media), yet they hold too small amount of data to be usable. And the 1990s floppies were not enduring enough read/write cycles to bother with them here (80s were a LOT better, I have one 720-kb floppy that's still readable, yet nowhere to read XDDD), maybe your world suffered the same. So, count tapes as damaged and unreadable without tools, floppies damaged or destroyed, depending on whether they are hardcover or not (3.5" are hardcover, 5.25" and 8" were not). **Summary** So, your best bet of recovering information from a personal media starts with books or written paper, followed by jet printed paper, followed by an external HDD, followed by a VHS tape, followed by a hardcover floppy disk. The biggest storage would be the HDD, followed by a VHS tape (with restrictions), followed by a written notebook, followed by a hardcover floppy (a notebook can hold a lot of more useful data than a floppy), followed by sheets of printed paper. Everything else you should consider being unreadable either completely or without very special tools, with a serious exception being HDD, that one depends on technology used - it might fall into both categories, depending on what happened to it over the year in space. [Answer] The problem of space is not vacuum, but all the rest: * magnetic fields: these would damage any storage medium based on magnetism, like a VHS tape * charged particles: these would damage solid state memories, magnetic storage, film * (dust) particles: these would damage the surfaces of anything exposed to them, so writings, carvings etc. Think of sandblasting a surface * radiation: it would break down complex molecules, affecting inks, colors, plastic and so on * thermal cycles: close enough to a star, anything going from dark to light would go from few K to several 100s K, resulting in mechanical damages The overall effect depends on the conditions of the exposure, in terms of time and energy. [Answer] My vote would be for something that's somehow ended up being retro-futuristic: minidiscs. [![A memorex minidisc with transparent casing](https://i.stack.imgur.com/lezMh.jpg)](https://i.stack.imgur.com/lezMh.jpg) (image credit [Evan-Amos via Wikimedia](https://en.wikipedia.org/wiki/File:Memorex-minidisc.jpg)) The [MD Data](https://en.wikipedia.org/wiki/MD_Data) format has been about since the '90s, and in its 2004-era form it could store 1GB of data. It has definitely been widely available, and though perhaps it was never that popular in the real world (and got discontinued in ~2012), we haven't had much crewed spaceflight beyond LEO for a few decades either so I think your fictional setting can stretch to it. Minidiscs are a [magneto-optical](https://en.wikipedia.org/wiki/Magneto-optical) storage medium. Amongst other things, they require local heating (generally provided via a laser) *and* a strong local magnetic field in order to write data to them, which means they're much more robust to ambient non-ionising radiation and magnetic fields than purely magnetic or optical re-writeable medium. They have a plastic casing around the disc that can protect against a certain amount of environmental stress such as UV and some kinds of impact. The major threat would seem to be micrometeorite damage, and that's hard to quantify as you've not given us much information about the orbit the objects would be in. 200000km is halfway to the moon, but that's an odd place to have a spacecraft in a circular orbit. A [Hohmann transfer](https://en.wikipedia.org/wiki/Hohmann_transfer_orbit) orbit between the Earth and the Moon would likely have a [periapse](https://en.wikipedia.org/wiki/Periapse) in low-orbit around the world the spacecraft was departing from, and that low orbit is likely to have a reasonable amount of human-made debris. Further out, impacts are likely to be much rarer. The JWST's mirror, all the way out at Earth-Sun L2 was expected to get struck [about once a month](https://www.space.com/james-webb-space-telescope-micrometeoroid-damage), but the mirror segments do have a total area of >22m2... more than 4500x that of a minidisc seen face on, so a free-floating disc in space might reasonably not be hit at all in a year. LEO is a much dirtier place though. [![Average cross sectional flux vs area chart, using ORDEM2000 data](https://i.stack.imgur.com/KtyQp.jpg)](https://i.stack.imgur.com/KtyQp.jpg) This chart was taken from [Sensitivity analysis of spacecraft in micrometeoroids and orbital debris environment based on panel method](https://www.sciencedirect.com/science/article/pii/S2214914721001999), and was derived from the [ORDEM2000](https://conference.sdo.esoc.esa.int/proceedings/sdc3/paper/91) dataset. There are newer datasets, but the ORDEM2000 set is fairly pessimistic and makes for a good worst-case, so I'll use it here. This assumes ~1000 strikes per square metre per year of 10μm debris. Now, if your disc had a large side facing the direction of travel for its whole orbit, that's a risk of 5 hypervelocity dust impacts per year. However: * That's a worst case scenario, and difficult to engineer... it would need to be entirely in LEO, and spinning at precisely one revolution per orbit in order to maintain the face-on orientation. * ORDEM2000 is fairly pessimistic, and other models like [SDEEM2015](https://conference.sdo.esoc.esa.int/proceedings/sdc7/paper/303) predict a 10-fold *lower* incidence of fine dust, enough to let your disc escape unscathed. * You probably wouldn't store minidiscs loose in your pocket.. A tough storage case for the disc will actually do a pretty good job of protecting against fine dust impacts... we're not talking about sand-grain sized things here, and objects larger than dust might not actually hit during that year in space. * There are areas of the casing that can be struck without risk to the disc inside. * It is possible to still read *some* of the disc even in the event of a certain amount of damage. * If it were edge-on to its orbit, it might reasonably not be struck at all. So there you have it. Whilst not necessarily as long-term or easy to read as paper, minidiscs might well work OK for your needs, and have a significant storage capacity and existing technology base to handle them. --- Also, honorable mention: [M-Disc](https://en.wikipedia.org/wiki/M-DISC), a write-once DVD/blu-ray storage system that came out in ~2010. It is chemically and thermally very stable, and assuming it avoided too much physical damage it might well survive OK. Whilst it came out a bit late for your timescale, the technology to *read* it was very readily available, and your setting is already deviating from the real world so it isn't too big of a stretch. [Answer] **Clay tablets** This quite far pre-2010, pre-2010BCE even. It seems unlikely that a modern person would be in possession of clay tablets, but perhaps they are an archeologist or Luddite. Maybe they just had some engraved periodic table tchotchke on their space station desk. [![enter image description here](https://i.stack.imgur.com/JEdYq.jpg)](https://i.stack.imgur.com/JEdYq.jpg) [Answer] **Digital Magnetic Tape** Before modern computers, early spacecraft use magnetic tape for all their data storage needs. Early Mars lander missions (Viking 1 and Viking 2) are good examples. The prime examples are the two Voyager Spacecraft. They still work and have been using 8-track digital magnetic tape since 1977. Granted, they are rather far away from the sun, but it's still insane to think that somewhere in deep space a tape-based computing system is still operating and has been doing so continuously for almost half a century. Here is an image of the tape deck in the Voyager Spacecraft and you can read more about [this here, on space.se](https://space.stackexchange.com/questions/2053/how-was-magnetic-tape-decay-prevented-in-voyager-1) [![Voyager Tape deck prototype](https://i.stack.imgur.com/3jbtt.jpg)](https://i.stack.imgur.com/3jbtt.jpg) Because of this, I think your best bet for slightly retro media would be a tape of some sort. There are lots of form-factors to choose from, and provided the tape isn't directly exposed to the sun but has some sort of case, I think even consumer-grade tape cassettes (audio, VHS) would be fine for at least a year. [Answer] You want a personal effect that will survive. Various answers have addressed the vulnerability of pretty much anything in common use. However, I can think of one item in modern use that I would expect the information to be retrievable from: a diary. Pen on paper in a notebook with a closure. It's closed so virtually all the abuse will be taken by the cover and the edges of the paper (and people usually don't write to the very edge), the actual written area is decently protected. It doesn't matter if the ink came off, a pen will etch the paper anyway. [Answer] Astronauts were constantly being hit by [micro-meteoroids](https://en.wikipedia.org/wiki/Micrometeoroid) on their moon trip which was just a few days each way. They're smaller than a grain of sand, but travel at an average of 22,500mph and would be constantly impacting. So unshielded I doubt any conventional data storage will be much good after a year. ]
[Question] [ I'm drafting up a world for a pet project of mine. I came across the idea of "what if there was a much longer night every *X* days?" I thought that would be an interesting theme for the world, so I'm trying to explore it. My first thought is that if there was a very large cloud of debris in just the right orbit, it might cause an extended eclipse, of sorts. To someone living on the surface, without telescopes, it would seem like there was a regular period of darkness. But, I'm not very familiar with cosmology/orbital mechanics, and I wanted to see if this was a plausible. And if plausible, what the necessary conditions might be. [Answer] ## Your world could be a moon of a (large) planet. That way, if your moon rotates along it's own axis, you would have a day/night cycle, but whenever it's behind it's planet it turns dark. You wouldn't get *very* long nights this way, even from Io, the closest large moon to Jupiter, Jupiter only takes up about 1/18 of the elliptic. I could do the numbers, but I doubt you would get more than a few hours of extra night time, tops, if you want to keep things moderately realistic. If you want to handwave how your world sticks together under the tidal forces, you could use this mechanism to make very long nights, though! Edit in response to @DarrelHoffman: Kepler's third law tells us that the period $P = \sqrt{k a^3}$, where $a$ is the average distance and $k$ some constant. Assuming a circular orbit for simplicity, the length of the orbit is $O = a \pi$, and we may divide these numbers to find the speed of the moon $v = \pi^{-1}\sqrt{k a}$. Specifically, the speed is monotone in $a$. If we assume the light rays are parallel, the length of the part of the orbit that's behind the planet is fairly constant, unless the moon is so close it's ridiculous. All in all, the time spent behind the planet thus is decreasing. So sorry, there doesn't seem to be any sweet spot! What occurs to me now would be to let the moon have a very eccentric orbit! That way, you could let it periodically end up behind the planet when it's at its furthest away, and therefore when it moves the slowest. You probably couldn't make it *that* excentric in practice, but possibly enough to make some different. This orbit would also make for very interesting seasons, and would likely make astronomy and/or astrology develop in interesting ways! [Answer] Natural debris? No, not really. At least, not unless you are in a *very* dangerous star system with lots of asteroid impacts--and even then, it would be a periodic dimming, not a total blackout. A mysterious alien megastructure, like a partial Dyson sphere? Sure. Heck, there are even proposals to that kind of thing *on purpose* for climate control. If you want an entirely natural explanation for varying day/night lengths, you could just put your planet in a binary star system. When the stars are far apart in the sky, days will be long and nights will be short. When the stars are close together, days will be short and nights will be longer. In this case, however, the maximal length of a night would be the "normal" nighttime--half a rotation period--with nights usually being shorter. [Answer] # Very Possible! Depending on your definition of "extended," this already happens with the moon. Consider also that Saturn's rings do cast a shadow on the planet. In any case, nothing in orbital mechanics prohibits this! As a side note, I doubt a cloud of debris would have the same effect as a solid body like the moon unless it was REALLY BIG. Smaller debris clouds would dim light shining through, but the light would still go through at random points. There is also the issue of multiple reflections within the debris cloud, which allows more light through than a solid body. # How to Solve This In theory, any orbiting body of sufficient size could extend nighttime with the right size, distance, and speed. Specifically, if you wanted exact numbers, you need an angular velocity of the orbiting body relative to the perspective of the planet to extend this darkness time. Once you have this (and how long it extends night by), you can then solve for mass and distance of the orbiting body. This will give a family of solutions, actually, because of the combined effects of mass and distance. So you will need to get an equation for the apparent size of the orbiting body, and fitler down your family of solutions by parameters that fit. To an observer on the surface of the planet, full eclipses are only possible when the apparent size of the sun is equal to the body providing the eclipse. You may still have multiple solutions here, so this is where you get to choose a mass or size and solve for that. # Some Examples A large enough sun-shield in a particular orbit would permanently shade a spot on the planet: specifically a Lagrange point of the planet-sun system. Go a little higher or lower in that orbit and this dark spot will move (more or less slowly, depending on the orbit). Another option is a moon in a highly elliptical orbit: it will spend a lot of time in the outer range of its orbit, potentially causing longer nights/eclipses. This adds a little complexity to our approach by varying the apparent size of the moon, as it looks smaller the further it is from the planet and still needs to dim/block the sun. There is a much smaller "sweet spot" for this situation than if we decided to use mostly circular orbits. [Answer] Natural cause? Can't come up with a new one. Consider a previous civilzation that put up a sun shield to reduce overheating. At the height of the civilization, it was kept perpendicular to the line between the star and the planet, and it was kept at the L1 lagrange point between the star and the planet. L1 is unstable, so it now drifts. And the control mechanism no longer keeps it perpendicular. So you get periodic partial eclipses. If it was highly reflective, you would also have a real glare when the sun and it made the right angles. Be difficult to predict. [Answer] This would happen even without debris cloud. If rotation speed of planet decrease causes nights to last long. Another dense planet might cause the reduction of rotation speed. And for the debris cloud, here is my answer, a **debris cloud can cause long nights**, but *it depends*, 1. Size of the home star of the planetary system. * If the star is small, more light would block by the debris cloud. 2. Distance between planet and star. * When distance increase, the amount of light fall on to the planet decreases, so when the planet encounters the debris cloud it is more likely to have darkness. 3. Thickness of debris cloud. * The more thickness have, it is harder for light to penetrate. 4. Materials that debris cloud made up of. * None reflective dark-colored (black) opaque debris would do the job. 5. And for longer nights, the debris cloud and the planet should revolve around the star towards the same direction with different speeds. * This make nights that exist for days, even weeks long. (Relative motion) ]
[Question] [ I sometimes tell my kid that when he grows up, he might be living on the moon. Last night he was worried that Santa won't be able to bring him presents there. To which I replied that sure, Santa can go quite fast, covering the entire globe in a 24 hour period. So, Santa wouldn't have a problem reaching across a distance of a mere [30 Earths](http://spaceplace.nasa.gov/moon-distance/en/). Would he..? It's just a matter or time, right? I'm no stranger to the various estimations of Santa's speed (different estimates of time he has and actual distance traveled): <http://www.telegraph.co.uk/topics/christmas/8188997/The-science-of-Christmas-Santa-Claus-his-sleigh-and-presents.html> <http://www.daclarke.org/Humour/santa.html> <http://www.fnal.gov/pub/ferminews/santa/> Let's say Santa gets a fresh bunch of reindeer, with their reindeer spacesuits and his jolly red santapacesuit, sets his sled's warp/wormhole/time distortion generator to max output, and heads out. **Can I get a fair estimate of how long will it take him to reach the moon and my kid** (How long will the boy be staying awake despite his father's protests). And oh, my son (or his son, or his grandson, or his clone's grandson's robotic heir) isn't the only eagerly awaiting kid on the block - the moon's gonna be heavily popualated in a couple of years decades centuries. So make it snappy! [Answer] # How fast does Santa go now? The population of the Earth is about 7 billion, and the land area is 150,000,000 km$^2$. Lets assume that people live in groups of 3.5 per 'household' on average (no idea if that is a good assumption), then Santa has to make it to 2 billion households over 150,000,000 km$^2$; or 13 per km$^2$. If those 13 per km$^2$ are neatly distributed within that square kilometer, we can approximate that he has 0.5 km to travel between each household (depending on how good Santa's traveling salesman algorithm is....say maybe I should ask for that for Christmas?). At half a kilometer between households on average and 2 billion households to cover, that means it take him a billion kilometers to hit everyone on Earth in one night. Defining the night is tricky too, but lets say he has 24 hours as the night swings its way around the Earth. That means he has to be going at about 11.6 11574(!!!) km/s to make it everywhere on time, assuming zero seconds for delivery. That is going to be a sun-of-a-gun for re-entry, but then given that he is already doing 0.039c (!!!!!!!!!!) in the atmosphere, and even at sea level, he's probably got some pretty great materials technology (definitely asking for that for Christmas). According to [xkcd](https://what-if.xkcd.com/20/), he should be causing fusion of the air in front of him as he passes through it. Gnarly! # How long does it take to get to the moon? At 384,400 km away, it takes only 33 seconds to get to the moon. # Conclusions Totally do-able! Now Mars is going to make things a little harder... [Answer] I think Santa would have more difficulty with lunar delivery than other answers suggest. We can't model Santa as a mere physical projectile and expect the results to be meaningful; the Santa-reindeer-gifts system is known to obey a set of additional rules which constrains his behavior beyond the ballistic model. In particular, while Santa is capable of impossible velocities, this ability has only been shown to function at night- more precisely, on *that one special night of the year.* We'll ignore possible effects from the inevitable encounter with sunlight as Santa travels between the Earth and the Moon; it is unclear if this would count as "day" in any event, and if Santa has some vampiric aversion to the Sun he could at least use a big parasol or something. The more direct problem is that a "day" on the moon (a synodic day, as we use on Earth) is as long as 29.5 Earth days. So, assuming a roughly even distribution of human colonists around the Moon, and supposing that Moon Christmas starts with the whole of the night side of the Moon on December 25th and progresses from there, there will still be Moon Cookies left out waiting for Santa's arrival on *January 8th.* That is of course a worst-case scanario; careful astrological calculations before you position your lunar homestead will ensure that Santa can reach your grandson roughly in time with the lucky Earth kids. And in either event, they'll be better off than Venusian colonists, for whom the old "Twelve Weeks of Christmas" will be roughly true. [Answer] It isn't the distance to the moon, which would worry me, but more the absence of atmosphere on the trip there and the presence of the atmosphere on the trip back. Santa would need a complete new set of sleigh, space suit and space proof reindeer. Currently Santa is moving 650 miles per second [according to this link](http://www.daclarke.org/Humour/santa.html). So, since the moon is 238900 miles away, it'll take him 367 seconds there and 367 back. With the training of new deers he may be able to beat the 6 minutes time. The biggest problem will be the re-entrance into earth atmosphere, where he'd probable turn into a huge ball of Christmas plasma, but at this point, I'd like to hand over to the real rocket scientists. [Answer] Reindeer cannot cross the vacuum of space. Not to mention Santa himself. That's why the elves keep posting questions to this forum about building physical bridges between planets, and why having a retractable one is so key. They'll be able to extend the bridge on Christmas Eve and take it down after Santa's return, before our sensors detect anything. Don't you worry -- the elves are well aware of our tech progress. They'll handle this just like the year they had to start making Atari game consoles in what used to be the wood shop. [Is it possible to build a bridge between planets?](https://worldbuilding.stackexchange.com/questions/64926/is-it-possible-to-build-a-bridge-between-planets) [Answer] # Tunneling This question and of course the answers I have seen thus far have all assumed "classical" mechanics. Instead, if we consider the Quantum Mechanical Santa Claus, we get much more sensible results. <http://www.amsat.org/amsat/archive/amsat-bb/200812/msg00543.html> In the case of a Quantum Mechanical Santa, he would be able to cross over to the moon via tunneling assuming * There is a potential preventing him from being observed in the space been Earth and the moon. * His Wave function decay is slow enough to reach the moon * There are observers on the moon Under such circumstances, Santa would instantaneously find himself on the moon. [Answer] There is a special Moon-Santa who stays on the moon and because of the lower gravity is able to jump anywhere he needs to go [Answer] Santa is a mythic role, much greater than a single man. Santa doesn't need to break the laws of physics and move so fast; he merely occupies millions of physical bodies simultaneously to accomplish his task. As such, Santa needs zero time to get to the moon as long as there already exists there a generous soul to manifest through. ]
[Question] [ Imagine you have someone sent back in time without warning. He is smart and has a good generalist grasp of science and technology, but is not a master of any particular field. He wants to use a crude microscope, for instance to demonstrate the presence of germs and thus germ theory. At what point in history would our mechanical and glass shaping skills be sufficiently advanced to build a rudimentary microscope given only a general explanation of concave mirrors 'stacked' on each other? Assuming that they had sufficient funding from an interested source to cover reasonable expenses and time to try a few failed attempts before the final product? Could this be managed during the middle ages? [Answer] You don't need perfectly ground lenses to make a microscope, much less the advanced optics knowledge to build compound, stacked lenses, modern microscope. This is Antonie van Leeuwenhoek's microscope (the first microscope in the world): ![World's first microscope](https://i.stack.imgur.com/zQbqF.png) The lens is just a glass sphere, nothing complicated. The slide is just a pin. With this he was able to discover: * cells * bacteria * sperm * the fact that microorganisms eat each other just like larger animals * the fact that microorganisms reproduce (it was popular theory back then that microorganisms spontaneously appear - like dust that suddenly come alive due to some chemical process) Some of his lab reports read like a Discovery Channel documentary of lions and zebras. Interestingly, people who tried to reproduce Leeuwenhoek's microscope (including some who wanted to be his competitor at the time and sell microscopes) didn't manage to produce his lenses via grinding. He never patented his lens making technique and kept it a secret. People later managed to reproduce his lenses by taking thin glass threads and melting the ends letting the glass form beads. So to build your first microscope, all you need is a glass blower competent enough to work with very-very fine glass threads. [Answer] Well according to [wikipedia](http://en.wikipedia.org/wiki/Microscope), the first microscope was made between the 1200's and 1600, so actually the middle ages are not that far off. You can also look at this page <http://en.wikipedia.org/wiki/Timeline_of_microscope_technology>, which links to the book [\*], which may probably answer all of your questions. About the fact of finding germs, it is said once again on [wikipedia](http://en.wikipedia.org/wiki/Bacteria#History_of_bacteriology) that the first bacteria was found in the 1600s thanks to a "single-lens microscope". So I assume that as soon as you have a basic microscope and that you look in the right direction, you can actually find germs. [\*]: Bardell, D. 2004. “The Invention of the Microscope”. [Answer] All you need is someone with the basic theory of lenses, and enough favor to get someone to help do the work. Glass has been around since 4000 BC. So any time after that you could get someone to form you some glass disks, and then practice grinding and polishing to get the shapes. It would take some trial and error if you'd never done it before, but the hardest part is knowing which lens shapes to use. Even a rough idea, along with the knowledge it's possible, would give you hundreds of years of advantage. So absolutely possible. [Answer] You can make a crude microscope by placing a drop of water on a slide to act as a lens. This brings the list of stuff he needed to have in his pocket down to a mirror (rescue signal mirror or makeup compact will work) two slides, and a slide cover. An eye dropper is also nice, but with practice you can use a finger to place a single drop of water. ]
[Question] [ Imagine a world that reaches the end of its resources in silicon, petrol, coal, metals... everything that allows for conventional technology — even before it has found a way over it (renewable energy sources, space exploration for mining...). Let's ignore the possibilities for stagnation or proper collapse of the society. What in this case would be the next logical progress for the society? What "technology" style would arise? What breakthrough? How likely are they? How do they solve / resume technological advancement? [Answer] A quick note here is that 'running out' isn't really a thing economies experience. Or at least the leading economy in the world has never experienced this. It's easiest to see with energy. A given material is popular at a given time because extraction economics favor it. Trees were once popular because they were everywhere and took hardly any effort to chop down. Coal became worthwhile as trees dwindled and we figured out how to dig effectively. But turns out that the advances in digging technology made it easier to get at oil and gas. And today, oil deposits are getting increasingly difficult to get at, so we're developing wind turbines and solar panels and the like. However, at each step along the way, the new resource didn't suddenly appear as we 'ran out' of the old one; it was there for quite awhile, just much less often used. Similarly, when we switched to the new resource, the previous one wasn't depleted. There are still trees, coal and there will still be oil by the time we switch to something else, **it's just more expensive to produce.** This is why we shift to new materials. What a given society thinks is 'too expensive' changes based on technology available, and at just about every point in history, technology has advanced faster than our exploitation of a given resource can reach cost-prohibitive levels. We've always had something new in the works whenever the old thing gets difficult to continue. Resources are never really disposed of, they just end up in increasingly difficult places. For example, it became more cost effective to mine garbage for aluminum than digging up the ores back in the 60s. The only way a material really becomes lost to us is if we throw it into space, which we presently do in trivially small quantities. If this ever becomes a common enough practice that it's a problem, it would likely imply an advance in spaceflight that make things like using the moon or asteroids for mining become more practical and at some point, mining our garbage will become less cost-effective than mining the moon. Perhaps we run out of technological advances waiting in the wings, waiting for a time when their exploitation will be profitable; that seems rather unlikely. It's often said that the Higgs boson is probably going to be the last major verified discovery of physics for a long time. Further particle physics research is going to require larger, more sophisticated accelerators to test. In physics, we've more or less hit the limit of how fast our technology can keep up with theory. In mathematics, we hit this limit well over a century ago. Presumably, since these two foundational sciences on the complexity ladder have surpassed our technical capacity, we might some day hit such points in chemistry and biology and all the rest. It's suggesting that theoretical research proceeds faster than technology can keep up (which makes sense in a way). As a result, we're going to have a lot of things we're pretty sure are there but need someone to get around to making. So we won't run out of things to invent. We've sort of got three rates of progression, economic being the slowest with technology a bit faster and research being much faster than that. Even if research stopped today, it's got quite the headstart on keeping the minds of engineers full of ideas. On the other hand, if we really did run out of stuff to invent, that means scientists have run out of stuff to study and we would understand pretty much everything. A world where humanity is omniscient of all the workings of the universe is a much different and exciting question. However, it's one I really don't think I can provide a decent answer to. [Answer] This is a concept that's arisen in sci-fi fairly frequently. Generally one of three things are portrayed to happen: 1. After a period of upheaval the society reverts to simple agriculture and stagnates at whatever technology and population level can be supported. Sometimes there remains a small group that still has access to the advanced technology but it is not accessible to the masses. 2. Civilisation collapses entirely. Think Mad Max roving hordes, people fighting over every last scrap they can get. This is one variant of the post-apocalyptic scenario popular with a lot of sci-fi. 3. There is some sort of breakthrough that changes the rules of the game. For example organic technology, synthetic fuels, solar power, nuclear fusion. A lot of interesting stories can be told along these lines, civilization on the brink of collapse or already collapsing while people struggle to perfect a viable alternative in time. **Future Tech** The problem with future tech is that ...it's future. If we already knew about it then we would have it. There are a large number of things in the near or medium term future that we can possible guess at. Reading sci-fi or speculative science articles will provide plenty of fuel for thought, but here are a few examples to get you started: 1. Bio fuels generated from sunlight 2. Moving away from transportation entirely (telecommuting, video chats, virtual reality) Then further into the future: 3. Fusion 4. Bio technology - artificial life tuned to perform certain roles 5. Quantum Computing Then from there we open up into pure speculation: 6. Completely new power sources 7. Major breakthroughs in physics or chemistry For example at any point, even tomorrow, someone could have a eureka moment and crack cold fusion, or antigravity, or teleportation, or something else we've never even heard of. When they do that the entire game changes. It could even seem really minor at first, the discovery of electromagnetism, or of lasers, were major breakthroughs that are now used everywhere around us but at the time their possibilities were impossible to predict. [Answer] I can think of two different ways of approaching this question, depending on what you mean by "conventional technologies". As I think both would be interesting questions, I will attempt to answer them both. # No more conventional technologies to discover Our own history has involved moving on from one technology to the next as we discovered better ways of doing things. I would call that a series of conventional technologies, even though each one is novel when it first appears. If you are asking what would happen when there are no longer technologies left to discover (due to a species reaching the current limit of its ingenuity) then the next technological step could not be a discovery. In that case the next technological step would be some kind of compromise. Unable to use technology to continue feeding an ever growing population, compromises may include population restriction, rationing of resources including food and water, or even reduction in body size to allow a larger population of smaller creatures. Metabolic rate may also be artificially restricted so that a slow living population can support greater numbers than the available energy would otherwise allow. When technology can no longer be used to provide more, it may be used to restrict numbers, restrict access to resources, or restrict the size or life rate of individuals. Given enough time these are all natural effects on a population in a restricted environment. For example, [dwarf dinosaurs](http://www.academia.edu/4843313/2010hateg_Dwarfing) and [reduced metabolic rate](http://www.uvm.edu/~pdodds/files/papers/others/2000/lovegrove2000.pdf) on islands. Technology may be used to speed up these effects in order to avoid conflict and suffering. It may be used to enforce equality in suffering so that everyone is a little bit hungry, rather than some starving. In the extreme case, a species may become unrecognisable due to the changes made, possibly even ceasing to be organic eventually. # The next conventional technology If instead you are looking for the next conventional technology, to allow continued growth of a population that can no longer be sustained by its current technology, then there are two ways of searching. You can look back or you can look forward. You can look back to earlier times and see if a technology that has been abandoned for being less practical might be adopted again due to being more efficient. Sometimes new technology is not more efficient that the previous one, just more convenient in times of plentiful resources. Looking forward is more difficult unless your world has technology similar to our past, allowing you to use our present as an estimate of their future. If you want to predict technology that we don't yet have ourselves, this is more difficult but there are some things you can do without needing to make genuinely new inventions. ### Look at the theoretical limits of current technologies For example the limits on communication, transport or computing. It is unlikely you can predict the specific details of improvements in computers over the next century, but you can read up on the [theoretical limits of computing](http://en.wikipedia.org/wiki/Limits_to_computation). This way you can give your world a level of computing power which is theoretically consistent with the amount of available energy and materials they have, even if you don't explain exactly how it works. ### Necessity is the mother of invention A good prompt for your imagination is to ask what a population in such a situation would most need. This won't give you the inner workings of the resulting technology, but it will allow you to present a more believable combination of unexplained (or partially explained) technologies. ### Be specific about what is in shortage It's not easy to imagine new technologies as a result of a shortage of everything. It's a lot easier to come up with new ideas if you just think about one specific shortage. For example, in a world with a water shortage you can think about what problems that would cause and what alternatives could be used. You need to drink water, but you don't need to flush the toilet with it. You can separate the current uses of water into essentials and luxuries, and come up with alternative technologies for the luxury uses and more efficient approaches to the essential uses. By imagining one shortage at a time, and adding to them, you can build up an idea of what might happen if a population was subjected to a number of different shortages over time. # Specific details There are of course far more specific potential answers, which you can access by posting further questions and narrowing down your requirements each time. [Answer] I know this is a late answer but I think this needs to be added and I haven't really seen the other answer emphasize it (besides Envite's, indirectly). # Recycling In Dune, there's little water so they make suits that recycle bodily fluids (sweat, urine) into drinkable water - they also have moisture farms (Luke Skywalker used to work in one on Tatooine, another desert planet). That's just one example. In real life we do this all the time - old metalworks get gathered and turned in for pennies and this contributes a lot to the availability of metals for industry. While recycling may not be a great way to save energy, it is a great way to make the most out of existing materials. At any point, you're going to have old technology around and old constructs, that can be refined into newer ones. The limiting factor is energy. Unless we're talking about a world without any energy (it can lack conventional *fuel* but it can't lack energy sources entirely), they can go through a time period of scarcity, as they adjust to different energy sources and recycle their old stuff into new stuff. This would of course raise the value of materials a great deal, but it can also depend on how efficient recycling is - if the techniques are developed adequately, it would be much like an unchanging supply of coinage, since the supply wouldn't grow or fade - the value of materials would be closer to the difficulty of recycling them versus their technological usefulness. Another effect would be a shift of research into transforming materials into one another. If you need an element and don't have it, you can work on forming it from others, shifting from scarcity of each material separately, to scarcity of material *overall*. You could have technology that creates rocks out of dirt or get sand out of stones to make glass. You could also find ways to use some of these materials as fuels - if you find some process that can turn uranium into plutonium efficiently (very implausible but it's just an example), you could then use it as fuel until it degrades and you can use it for something else. *I know we're talking about all resources being gone, but you might still have waste from old reactors and you can still transmute other metals to uranium or whatever*. [Answer] [The Mote in God's Eye](https://en.wikipedia.org/wiki/The_Mote_in_God%27s_Eye) is a novel (nominated for the Hugo and Nebula awards) in which humans make contact with a race that has depleted their world from metal. Do not continue reading this if you want to read it! I strongly recommend it. > > In that world, the society has cycles of increasing population and > development until there are no more resources, when it comes world war > for resources and population strongly reduces almost to the point of > non-survival, and technology disappears. Then they grow again, thanks > to an innate "superpower" of their mechanics, able to build almost > anything from any other thing with no new materials, just reformatting > existing metal and plastic. > > > [Answer] Technological development would be focused around resource production (probably especially energy). Depending on their situation, they may focus on going to space, or going into the earth. Depending on the parameters around them they may try to go to an alternate universe or use magic. In order of likely hood (in my opinion): * Going to space. Civilization would work on a way to use remaining resources to enter space and collect new resources. * Going into the earth. The civilization would try to go deep into the earth to get geothermic energy/materials buried deep * Develop magic. This depends on how the rest of the world is built. If magic exists, civilization may try to use magic to get the resources and energy it needs. For example, if people could produce electricity with magic, then maybe society would enlist these people to make electricity to supply power for technology. Technological advancement would depend on how society stuck together. If everyone went out for themselves, likely no more advancement would be made until a remnant of society was rebuilt. If society was stuck together, it is likely that technological advancement would be seen as the only way out and would be focused on. [Answer] As your civilization sees it's end nearing all nations put their differences aside to solve the problem you put forth by a most ingenious method; they build a self-learning machine intelligence and give it the instruction of solving the problem of diminishing resources. So they go at it and at some point the machine reaches enough basic intelligence to start learning. It decides to make itself smarter to be able to solve the problem it's been given. Two minutes later it reaches near infinite intelligence. Five seconds later it launches every nuke on the planet to every city it can find, irradiating everything. The machine solved the problem of diminishing resources by cutting out demand, making sure te remainder will now last forever. ]
[Question] [ So far I had no luck trying to find the visible absorption spectrum of CO₂ anywhere, all I get is the far infrared absorption spectrum and stuff like that. If you just search "what color is liquid CO₂" it simply says everywhere that "it's colorless" but... That's also said a lot about other liquids such as water, but we all know that's not true. Water is not colorless at all, it just appears colorless in small quantities since it's a very transparent liquid, and one can only appreciate its slightly blue coloration in very large quantities such like in pools, lakes, oceans, etc. Water is not just blue because of Rayleigh scattering and the sky's reflection, it is also and mainly blue because it does in fact absorb more red and green light than it absorbs blue light, just like any other blue thing. That being said, I don't think liquid CO₂ is colorless, I think it's just appears colorless in small quantities, but in very large quantities some color is perceivable, exactly just like it happens with water. But I might be totally wrong since that belief is based on absolutely nothing, that's simply how I guess it is since I have absolutely no idea and it's hard to imagine a liquid that totally ignores visible light lol I had this question unanswered for a looong time, would love to finally get an answer. Thanks in advance! [Answer] ### Blue ![enter image description here](https://i.stack.imgur.com/3c2sG.jpg) CO2 has the same transparency as H2O over the visible light range (380 to 700 nanometers). At 3 atoms, CO2 also has about the same particle size (232 picometers) as H2O (282 picometers). Rayleigh scattering is largely dependent on particle size. CO2 is 17% smaller, which is squared in the scattering equation, giving you a slightly more intense scattering (2%) of all visible frequencies, including blue. Based on these two data points, liquid CO2 oceans will look like H2O oceans in the visible light range. Which is to say, a kind of blue. In the infrared range, things will be different. Water is black in infrared, where a CO2 ocean will continue to be largely transparent. [Answer] As best I can tell, liquid CO2 is clear: it doesn't absorb any wavelengths in the visible light spectrum. In large quantities it would likely be subject to [Rayleigh scattering](https://en.wikipedia.org/wiki/Rayleigh_scattering), giving it a bluish color similar to a water ocean, which I suppose could be altered by particulates ([Mie scattering](https://en.wikipedia.org/wiki/Mie_scattering)). No one that I can find has published the index of refractivity of liquid CO2, likely because it's not a particularly common substance. I have seen people note that the index of refractivity of *gaseous* CO2 increases with pressure, and my guess would be that liquid CO2 (at the pressures it exists) would be noticeably more refractive than water. [Answer] **As With Water, It Depends** CO2 is colorless to the human eye due to the mechanics of particle physics. It's liquid form is therefore a reasonable analog to H2O. H2O has its color depending on circumstances. [According to the National Oceanic and Atmospheric Administration](https://oceanservice.noaa.gov/facts/oceanblue.html), the 'default' color of H2O is 'blue,' but the effect that makes this so is fairly weak. The dominant coloration of water (and CO2) oceans is dependent on the size and nature of the body and what else is contained within it. Particles in suspension in a body of clear liquid will easily overwhelm the coloration of those bodies. This is how oceans can appear green, red, black, and with the right pollutants any color you darn well please. A thing to note with CO2 ([From this fact sheet](http://www.fao.org/3/w6355e/w6355e09.htm)) is that the conditions which cause it to take liquid form also tend to cause a portion of it to form a solid - dry ice. Dry Ice is distinctly white. Depending on the conditions you are envisioning this liquid ocean of CO2 to exist within, it seems likely that from long distance these oceans would appear mostly white, as the ice portion of the water would overwhelm all other factors. Various degrees of turbidity (depending on wave action, or even organic behavior for example) would further mess with this. For shallows, under a no-ice scenario, the coloration of the sea bed would also play a powerful role. [Answer] Building on [Ted Wrigley](https://worldbuilding.stackexchange.com/users/66915/ted-wrigley) answer. Our eye can "see" wavelengths between 380 and about 750 nanometers. [![Wavelengths and visible spectrum](https://i.stack.imgur.com/zKSdy.png)](https://i.stack.imgur.com/zKSdy.png) What makes water (H20) blue is that, on our visible spectrum, the absorption coefficient of the wavelengths which our eyes identify as "blue" is close to none, reflecting the rest of it (just like you pointed out). [![Visible light absorption spectrum of pure water ](https://i.stack.imgur.com/DAyB1.png)](https://i.stack.imgur.com/DAyB1.png) I looked around CO2 absorption spectrums. Most of them either used a wavelength domain from ultraviolet to microwave, or solely focused on infrared. The ones where i got some answers were: * <http://irina.eas.gatech.edu/EAS8803_Fall2009/Lec6.pdf> * <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174548/> You should notice there that there is no absorption in the visible spectrum, making it basically clear, and if there is, it is so minimal that might not make a difference to the human eye. [![Transmission spectra of some atmospheric gases.](https://i.stack.imgur.com/iw0eQ.png)](https://i.stack.imgur.com/iw0eQ.png) [Answer] **Liquid CO2 does not absorb light in the visible spectrum.** [![wavelengths](https://i.stack.imgur.com/MS8zK.jpg)](https://i.stack.imgur.com/MS8zK.jpg) for reference. [source](http://www.physicalgeography.net/fundamentals/6f.html) [Effects of Temperature on the Near-Infrared Absorption Spectra of Molecules in the Condensed States. I. Carbon Dioxide1. Waggener et al. Journal of Physical Chemistry 1967](https://pubs.acs.org/doi/pdf/10.1021/j100872a025) > > Liquid carbon dioxide, in cells of several centimeters, does not > absorb measurably in the wavelength region from 0.3 to 1.2 u- Its > spectrum in the region between > 1.2 and 2.5 u is shown in Figure 2, and the principal bands are identified. > > > Visible light is 0.39 to 0.76 so falls in that range. CO2 does absorb in the infrared and ultraviolet but not in visible light. The liquid CO2 ocean would be colorless. --- I see it mooted that liquid CO2 would be blue like water because of Rayleigh scattering as happens in the sky. Water is not blue from Rayleigh scattering. It is blue because it absorbs in the red frequencies, and so with enough depth blue is what remains to scatter back to us. <http://www.webexhibits.org/causesofcolor/5B.html> > > Water’s intrinsically blue color is easy to see when the water is > sufficiently deep, such as in the Caribbean and Mediterranean Seas, > and in Colorado mountain lakes. Pure water and ice have a pale blue > color, which is most noticeable at tropical white-sand beaches or in > ice caves in glaciers. (Green colors are usually derived from algae.) > The blueness of the water is neither due to light scattering (which > gives the sky its blue color) nor dissolved impurities (such as > copper). Because the absorption that gives water its color is in the > red end of the visible spectrum, one sees blue, the complementary > color of orange, when observing light that has passed through several > meters of water. Snow and ice has the same intense blue color, > scattered back from deep holes in fresh snow. > > > Of course if there were suspended particles in the CO2 ocean those might participate in Rayleigh scattering. Any sort of impurities could impart color because the CO2 will be optically clear. [Answer] Because of the intense pressure required to support the existence of liquid CO2, there would have to be a thick atmosphere, which makes me think that you wouldn't be able to see the liquid CO2 ocean from space. Even on a planet with gravity that would create such surface pressures there would still be a ridiculously thick atmosphere. Furthermore the concentrations of CO2 and other greenhouse gasses in the upper atmosphere would have an insane greenhouse effect that would make the planet insanely hot, perhaps so hot that it physically would not allow for liquid CO2 for very long. It would have to be an exoplanet, perhaps even some kind of 'planet like interstellar object'. [Answer] Okay, I'm not very sure if my answer is correct, but I think that it the color would differ if in different depths, like water, and if, for example, the depth of the water/liquid CO₂ was, let's say, 1,000 feet, then I would say that the color of the water/liquid CO₂ would be maybe a dark navy blue, seen in space, of course, because of the depth. If the depth was at around 50 feet, then I'd say the water/liquid CO₂ would be a azure blue (again, seen in space), but again, I'm not very sure if my answer is correct. I would agree with you that liquid CO₂, just like water, is transparent, or having no color, in small quantities. [Answer] **Blue** > > Liquid carbon dioxide mainly exists when carbon dioxide is dissolved > in water. > > > To exist in liquid state would requiere to dissolve in water, as pure water has a blue tint, this is the color that the Carbon dioxide ocean would acquire. [https://www.lenntech.com/hazardous-substances/carbon-dioxide.htm#:~:text=Although%20carbon%20dioxide%20mainly%20consists,soluble%2C%20when%20pressure%20is%20maintained](https://www.lenntech.com/hazardous-substances/carbon-dioxide.htm#:%7E:text=Although%20carbon%20dioxide%20mainly%20consists,soluble%2C%20when%20pressure%20is%20maintained). ]
[Question] [ In my world a Roman emperor (any emperor of any period of the Roman Empire for the purpose of this question) decides to create the tallest possible tower (measured from base to the highest floor reachable by traditional steps), and is willing to build it anywhere in his empire where it would make the most sense to do so. The cosmetic style of the tower should be similar to [other buildings of the Empire](https://en.wikipedia.org/wiki/Ancient_Roman_architecture), and can't use techniques outside the understanding of this era/region of architecture. The building can be as wide as needed (even surpassing the Colosseum, if needed), circular on the base, and should be vaguely tower shaped (such as the later Tower of Pisa, as an example). The tower is a monument to himself and the empire, and is intended to be able to be used, with small events held within. The tower has no set practical purpose, but it must be serviceable to host random events *inside* to showcase it. The tower should be stable enough to last through the centuries. The height shouldn't be considered the tip-top of a spire, but instead the height of highest floor that can be reached via conventional stairs. Height is measured from the base to this floor. The emperor wants to build this tower as high as he possibly can. How high can I justify this tower being? [Answer] Nobody knows. Roman writer Pliny the Elder scoffed at the useless pyramids and considered many Roman buildings to be both greater and more useful. This implies that the taller and more impressive the Emperor built his tower the more the Romans would have complained about the waste of money unless it had some practical use as well. If the emperor had a practical use for the tower then the Romans would have approved of it. What sort of proportions would the tower have to have to be considered a tower and not a building? As tall as wide, twice as tall as wide? 1. I could imagine a city with a tall cliff at one side. There could be a tower perhaps hundreds of feet tall with a vast room in it used as a water tank maybe 100 feet in diameter and 100 feet high. An aqueduct would cross from the edge of the cliff to the tower and bring in water to the top of the water tank. The water would flow out the bottom of the water tanks, still at least fifty feet above street level, through pipes and be distributed around the city. There could be a viaduct alongside the aqueduct so people could reach the top of the water tank. If the water tank had a concrete dome the walls would have to be very think, like 20 feet, and a ring of rooms about 20 feet wide could have been built on top of them to help buttress the dome. Or the water tank could have a flat wooden roof and rooms could have been built on it. Thus there could be rooms for parties on top of the water tank. And above the rooms could be a viewing platform that might be hundreds of feet above the city depending on how tall the water tank was and how high the water tank's bottom was above street level. 2. The [Sanctuary of Fortuna at Palestrina](https://www.google.com/search?q=sanctuary%20of%20Fortuna%20at%20Palestrina&sa=X&espv=2&tbm=isch&tbo=u&source=univ&ved=0ahUKEwiHms2bxqnTAhWI54MKHVndC_EQsAQIWA&biw=1280&bih=894&dpr=1#imgrc=_%5B1%5D) built about 120 BC on a series of terraces on a hillside had a very impressive total vertical dimension. But I don't know what was the greatest height of open interior space as opposed to filled in terraces. Obviously an emperor could have built a similar structure which appeared to be a tower from the outside if it was built on narrow terraces on a narrow tall hillside. 3. The emperors built [several platforms](http://romereborn.frischerconsulting.com/ge/FT-008.html) from the sides of the Palatine Hill on tiers of arches to support additions to the Palace. These platforms may have been 50 to 100 feet tall, and then palace buildings were built on top of them. Septimius Severus built the Septizodium or Septizonium in front of one such palace wing. Italian archaeloogist Rudolfo Lanciani believed the Septizodium had been seven 30 foot stories tall, and thus 210 feet tall, and had been built to screen that palace wing, that thus should have had a total height of 210 feet. Modern archaeologists believe the Septizodium was only three stories high. 4. Many medieval Italian towns and cities looked like Manhattan with many tall slender towers belonging to noblemen. The few remaining in [Bologna](https://en.wikipedia.org/wiki/Towers_of_Bologna) out of about a hundred range from 32 meters (104.987 feet) to 97 meters (318.241 feet). The [*Torre de Mangia* in Siena](https://en.wikipedia.org/wiki/Torre_del_Mangia) is 102 meters (334.646 feet) tall. I would guess that a Roman Emperor could have built towers that tall. 5. The Donjon of the 13th century [Chateau de Coucy](https://en.wikipedia.org/wiki/Ch%C3%A2teau_de_Coucy) was 35 meters (114.829 feet) in diameter and 55 meters (180.446 feet) tall. A Roman Emperor, with many thousands of times the wealth, could probably have constructed similar structures. This [plan](https://en.wikipedia.org/wiki/Ch%C3%A2teau_de_Coucy#/media/File:Coupe.donjon.Coucy.3.png) of the donjon of Courcy shows it had three great rooms, one above the other. 6. That immediately makes me think of building a tower with three [Pantheon sized rooms](https://www.google.com/search?q=pantheon%20elevation%20drawing&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjN3YGr3qnTAhXh3YMKHYzXBEkQ_AUIBigB&biw=1280&bih=894#imgrc=_%5B8%5D) in it, one above the other, for a total height of 450 feet. And then a fourth Pantheon room could have built on top, this time out of wood or at least with a wooden dome to save weight. The Romans could certainly build wooden domes with half the diameter of the Pantheon Dome, and so might have been able to build a Pantheon sized one. In fact I have read a theory that the original Pantheon of Agrippa had a wooden dome approximately the same size as the concrete dome of the present Pantheon. If I was building such a building on top of a tower of Pantheons I would have inner and outer walls about 20 feet apart, the outer wall considerably higher than the inner wall, and build wooden domes on top of both the inner and outer walls. Since the outer doom would be 40 feet wider in diameter than the inner dome and would spring from a higher level there would be plenty of space between the two domes for wooden beans and trusses to connect and mutually support them. And there would be space between the two domes for stairs leading up to the top and a viewing platform 600 feet high atop the tower of Pantheons. Of course, that building is imaginary and was never built. 7. The Colossus of Nero was a statue 106.5 Roman feet (30.3 meters or 99 feet) tall, or possibly 37 meters (121 feet) It stood in the *vestibulum* of Nero's Golden House, possibly a courtyard, or a niche in an exterior wall, or in a room. From [Suetonius](http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Suetonius/12Caesars/Nero*.html), > > There was nothing however in which he was more ruinously prodigal than in building. He made a palace extending all the way from the Palatine to the Esquiline, which at first he called the House of Passage, but when it was burned shortly after its completion and rebuilt, the Golden House. Its size and splendour will be sufficiently indicated by the p137following details. Its vestibule was large enough to contain a colossal statue of the emperor a hundred and twenty feet high; and it was so extensive that it had a triple colonnade a mile long. > > > This translation certainly makes it seem like the colossus was inside a room. I have read that Nero had a life size painting of the colossus made, and hung it in the atrium of a villa built by Caligula on the outskirts of Rome. If the atrium was a courtyard or room it should have had a wall at least 100 to 120 feet tall to hang the painting. 8. I once read that the palace buildings Caligula built on the Palatine were built of wood, unlike most masonry Roman buildings. How tall a tower could a imperial megalomaniac like Caligula have built out of wood, if he wanted to? The Yongning Pagoda was described in *Record of the Buddhist Monasteries in Loyang* to be 90 Zhang high and 100 Zhang with the spire, or 330 meters (1082.68 feet), but in the commentary of the *Waterways Classic* "only" 49 Zhang or 163 meters (534.777 feet). Archaeologist Yang Honxun who excavated its foundations believed it was about 147 meters (482.283 feet) tall. See discussion [here](http://historum.com/asian-history/46370-why-do-ancient-chinese-architecture-hardly-ever-go-up-9.html), page 9, posts 88 and 89. Note that the Great pyramid is 138.8 meters (455.38 feet) tall and was 146.5 meters (480.643 feet) tall when completed. The facing stones were loosened in an earthquake in 1305 and later carried away, and the pyramidion at the top is missing. So if Calgula wanted to he could probably have built a wooden tower hundreds of feet tall. 9. The Legendary [tomb of King Lars Porsena](https://www.google.com/search?q=tomb%20of%20lars%20porsena&noj=1&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjD1JLGgarTAhUq44MKHe_MA4MQ_AUICCgB&biw=1280&bih=894) of the Etruscan city of Clusium was described in a way hard to visualize. it was supposed to be 200 meters (656.168 feet) tall. If an Etruscan King of a city state could build such a structure about 500 BC I guess a Roman Emperor could have built something just as tall - however tall it really was. 10. There were a number of important ports in the Roman Empire, like Ostia and Portus, the ports of Rome. The Romans could have built tall towers as light houses at those ports, as tall as the Pharos at Alexandria. The [Pharos at Alexandria](https://en.wikipedia.org/wiki/Lighthouse_of_Alexandria) is believed to have been about 120 to 137 meters (393.701 to 449.475 feet) tall. Or [115 to 135 meters](http://www.crystalinks.com/lighthousealexandria.html) (377.297 to 442.913 feet) feet tall. In fact the Romans did convert the Pharos from a tower seen by day to a light house that could be seen at night, and did build some other light houses. The Roman light house or Pharos at Dover, England now stands only 60 feet high. > > Today the pharos is only a four-storey building at 19 metres or around 60 feet high with the top floor section being a medieval restoration, but originally it was six levels high at 24 metres or 80 feet and, maybe even eight levels high, according to some Roman historians? > > > [https://thejournalofantiquities.com/2013/05/12/the-roman-lighthouse-dover-kent/[13]](https://thejournalofantiquities.com/2013/05/12/the-roman-lighthouse-dover-kent/%5B13%5D) The Tower of Hercules in Corunna, Spain is an ancient Roman lighthouse. > > he Tower of Hercules (Galician and Spanish: Torre de Hércules) is an ancient Roman lighthouse on a peninsula about 2.4 kilometers (1.5 mi) from the centre of A Coruña, Galicia, in north-western Spain. Until the 20th century, the tower itself was known as the "Farum Brigantium". The Latin word farum is derived from the Greek pharos for the Lighthouse of Alexandria. The structure is 55 metres (180 ft) tall and overlooks the North Atlantic coast of Spain. The structure, almost 1900 years old and and renovated in 1791, is the oldest Roman lighthouse in use today. > > > The tower is known to have existed by the 2nd century, built or perhaps rebuilt under Trajan, possibly on foundations following a design that was Phoenician in origin. It is thought to be modeled after the Lighthouse of Alexandria. At its base is preserved the cornerstone with the inscription MARTI AUG.SACR C.SEVIVS LVPVS ARCHTECTVS AEMINIENSIS LVSITANVS.EX.VO, permitting the original lighthouse tower to be ascribed to the architect Gaius Sevius Lupus, from Aeminium (present-day Coimbra, Portugal) in the former province of Lusitania, as an offering dedicated to Mars. The tower has been in constant use since the 2nd century and is considered to be the oldest existing lighthouse in the world. > > > In 1788, the original 34 metres (112 ft), 3-story tower was given a neoclassical restoration, including a new 21 metres (69 ft) fourth storey.[14](http://www.ostia-antica.org/portus/c001.htm) The restoration was undertaken by naval engineer Eustaquio Giannini during the reign of Charles III of Spain, and was finished in 1791.[14](http://www.ostia-antica.org/portus/c001.htm) Within, the much-repaired Roman and medieval masonry may be inspected. > > > [https://en.wikipedia.org/wiki/Tower\_of\_Hercules[15]](https://en.wikipedia.org/wiki/Tower_of_Hercules%5B15%5D) It is kind of disappointing that it was originally only 34 metres (112 ft) tall. This article suggests that the lighthouse built by Claudius at Ostia was probably taller than the Pharos at Alexandria. [http://www.ostia-antica.org/portus/c001.htm[14]](http://www.ostia-antica.org/portus/c001.htm%5B14%5D) If that is correct then a Roman Emperor did build a tower more than 300 feet tall, possibly more than 500 feet tall. There would be rooms and stairs up to the highest floor, which would be used for working the light house and not for events, of course. The Cordouan Lighthouse built 1584-1611 in France was 162 feet (49 meters) tall and had a king's apartment on the second story. [https://en.wikipedia.org/wiki/Cordouan\_Lighthouse[16]](https://en.wikipedia.org/wiki/Cordouan_Lighthouse%5B16%5D) Thus it is always possible that the pharos at Ostia had rooms sometimes used for imperial events, lower than the light room. [Answer] Most historians and archaeologists agree that the [Lighthouse of Alexandria](https://en.wikipedia.org/wiki/Lighthouse_of_Alexandria) (built in the 3rd century BCE) was about 120 to maybe 137 meters (400 to 450 ft) tall. If this is true then it would have been the tallest tower in the world until the construction of Malmesbury Abbey Tower in 1180. This should give you a rough idea of how tall a tower the Romans could have built. [Answer] Roman buildings always have some use. So we are looking at high utilities. High utilities usually won't calify as towers, unless they are lighthouses (see other answers). Oh! We could also use an acueduct tower. Usually acueducts are only underground, but in the case you had a city in the middle of a big big BIG plain, there would be some possibility of having something very high. The only way of this height happening is if the acueduct had to make a turn in the middle of the plain, where pressure would be higher. As corners inside a pipe make a weak spot where the pipe could burst, Romans lifted the pipe to the height of atmospheric pressure in the pipe to make a turn/corner at atmospheric pressure. [![Giro de acueducto1](https://i.stack.imgur.com/RX7z8.png)](https://i.stack.imgur.com/RX7z8.png) [![Giro de acueducto2](https://i.stack.imgur.com/75UEw.png)](https://i.stack.imgur.com/75UEw.png) The limiting facts for that are the distance of the plain, the pressure inside of the pipe and the absence of any other source of clean water (river water is not healthy). For more info on Roman Engineering I suggest looking up Isaac Moreno Gallo on Youtube, he's an archeologist or an engineer or a mix of the two, I'm not sure. His videos are what gave me the idea. Source: [video](https://www.youtube.com/watch?v=IIy9VWnfu8I) ]
[Question] [ One of the bigger difficulties is the storage of information is that the more efficient information is stored, the quicker a single person can learn, and thus the more they know. This becomes extremely efficient when books come into play and starts on a quick rise after the population becomes literate. But sometimes a species cannot create this basic binding of paper, perhaps they are polymorphic, perhaps they are blind. The reason why they cannot create books doesn't matter, the next concept is. Inspired from the 'spiders' from Stephanie Meyers, The host; > > Each new Spider was born knowing what the last knew, so knowledge was never lost > > > This concept has struck me as extremely interesting, the idea of memory being passed on to the next generation seems very unusual and yet oddly fascinating. *Is there any way to explain how memory could be passed on to the next generation?* [Answer] **Mystically:** your fictional people remember their past incarnations. With a bit more of handwaving this [ceases being mystical and can actually go scientific](https://worldbuilding.stackexchange.com/questions/47181/how-can-i-scientifically-explain-the-afterlife/47184#47184). **Mystically, version 2:** your beings can access the [Akashic Records](https://en.wikipedia.org/wiki/Akashic_records). Depending on the mystical school describing these, they may contain from just thoughts and desires of everyone who has ever lived to each and every detail of the whole history, past and future, of each particle in the universe, so taylor it to your needs. **Genetically:** as seen in Assassin's Creed. This has an advantage that you can limit the amount of information that a species can carry from one generation to the next, if you wish. **Genetically, version 2:** as seen in Steven Universe. Gems are born when a planet's crust is seeded with a kind of genetic matrix for their species. The matrix contains not only the instructions for their shape and composition, but also all the knowledge that they will have upon birth. **Genetically, through horizontal transfer:** if genes can carry memories, these memories can be implanted into someone else through viral infection. Virii will sometimes incorporate genes of one host, and when they infect new hosts later on, the more recent host will have some of the previous host's genes implanted on their infected cells. This is called horizontal gene transfer and it is a thing in nature. Alternatively this may be achieve through genetic engineering/therapy, for a more controlled and accurate effect. **Telepathically:** as seen with the Zerg species in Starcraft. A Zerg learns all they need to know via telepathy, being instructed by the hierarchy that spawned them. They are guided, in ascending order of rank, by hatcheries, overlords, cerebrates and on top of that an overmind. **Technologically:** you can have a brain implant installed on the brain of a newborn to kickstart its brain with memories from other people (or even fabricated memories). See *Ghots in the Shell* (movie and animé), and the awesome sci-fi books *Old Man's War* and its sequel *The Ghost Brigades* by John Scalzi. Though your species may have no technology of their own, a more advanced benefactor may implant stuff on them. **Technologically, version 2:** Again an implant, but this time to link everybody together like a hive mind. The technological version of telepathy. *[Star Trek's The Borg](https://en.wikipedia.org/wiki/Borg_(Star_Trek))* work like this. This way everybody can access the same knowledge, or maybe a secured version per family. This technique could also allow a human version of cloud computing. See Joe Haldeman's *The Forever War* and *Forever Free* for a variation on this theme. **Magically:** again as seen on Assassin's Creed. At some point the protagonist of the original game transfers his memories to a set of discs (such discs are technological in nature, but that technology is advanced enough that it is indistinguishable from magic for all purposes). One of his descendants absorbs those memories from the discs a few centuries later. This memory transfer method does not rely on the genetic memory transfer method on which the series is based. **Magically, version 2:** as seen in Steven Universe. Gems can fuse among themselves to form new beings. These beings have the memories from the gems that fused. They are also able to use any component's wisdom, insight and personality to judge, handle, process and combine any other component's memories, thus being able to have much more knowledge than the mere sum of each isolated component's memories. **Organically:** those trees from James Cameron's *Avatar*. People can connect to those to upload and download memories. Seems like whole forests are interconnected as well. Failing all those... Maybe the species reproduces by binary fission, like bacteria. Each child will have the memories of their parent. I have read that this is the case with starfish when an arm regenerates a whole body, but I can't find any sources confirming this now. [Answer] In humans, the embryo is built, essentially from scratch, from a fertilised egg. Reproduction doesn't have to be like this. In your species, the embryo begins not as an egg but as a bud on the side of the mother's brain (which is conveniently located in the mother's torso). This bud forms a cyst around itself, but it remains connected by a bundle of nerves, which allow the developing brain to interface directly with the mother's. The mother's thoughts and the foetus's are shared. The foetus learns from the mother's experiences. The mother has direct experience of the grow mind within her body. The brain bud then develops a placenta like structure which draws nutrients from the mother, and causes the embryo's body to grow. Eventually, the nervous connection withers as foetus becomes independent, shortly before birth. In that scenario the baby is genetically identical to the mother. There could be sexual reproduction: You could have a parasitic male, that buries into the female body, rests on the brain, and the genetic merging of his and her brain tissue starts the brain bud described above. In this scenario, the embryo has genes from both mother and father, but memories only from mother. [Answer] Well, sort of. The form that evolved intelligences always seem to take is a complex of super-interconnected thoughts, which can't really be separated wholesale from the intelligence itself. Or rather, they could, but it would be so incredibly delicate and computationally expensive that there is essentially zero chance of it ever evolving (note: this also includes telepathy). The only ways I could think of it coming about are if it was engineered by some advanced super-race, or if the aliens reproduced by temporarily shutting down their brains and then duplicating them cell-by-cell. In the latter case, the resulting spawn would be psychologically identical to the parent, which isn't ideal. Perhaps, the spawn is then flushed with hormones and such that "reset" most of their brain, turning the ancestral memories from "experiences" to "known facts"? That said, the "right" answer while writing something is probably "sure, if you want it to". Most of Renan's answers are good ones. All of them except the genetic memory one, really, which draws the ire of pretty much every nerd with any knowledge of genetics or information theory. Although I suppose it is a good way for a *bioengineered species* to have ancestral memory. For example, have a section of the brain specifically dedicated to monitoring the rest of the brain, and whenever something significant happens, that section "writes it down" in DNA and uses specialized blood cells to send it off to the germ cells. This organ would probably also be responsible for turning the ancestral DNA-memories into synapse-memories during brain development. [Answer] I would recommend the book ["A Fire Upon the Deep"](https://en.wikipedia.org/wiki/A_Fire_Upon_the_Deep) by Vernor Vinge. The story revolves heavily around a planet where the native life evolved very sensitive sound organs. One species, the Tines, was able to become sentient through an acoustic group mind. Sentient Tine persons would consist of 4 to 8 less-than-sentient individuals sharing their thoughts directly through quiet and intricate buzzing. Tine persons were effectively immortal since their young would immediately be incorporated into one of their parents' group minds and programmed with cognitive duties and memories. It would eventually take the place of older individuals that died off. ]
[Question] [ Imagine a coordinated attack by a large and motivated hacking group, that results in a nation-level compromise of the financial systems we take for granted: credit card payments, accounts at the top banks, the ACH system etc. Funds become frozen, and so do individuals and corporations, financially. Illicit transactions remain uncorrected until trust can be re-established. Digital trust, on which a staggering amount of our modern society's functioning is based, drops to near-zero levels. Can we prevent total chaos? If not, how could our society recover? [Answer] In the very short term you may see activities similar to those already used by banks during major outages. * greater powers to branch staff to allow small payouts to known/regular customers without electronic confirmation * raising of those small limits * inter-bank couriers with cash and payment orders * etc Trust relationships are relatively straightforward to reinstate: you work through trusted individuals, and banking does have a good peer relationship network in addition to government facilitated communications. The return to business will rely on rebuilding to known good platforms, so organisations that can do that for key services within hours will be in the strongest place. [Answer] Nation level is interesting - that suggests that the rest of the world is still able to function, to some extent, whilst within the targeted nation the financial system is in complete collapse. I think a lot of it would depend on the specific nation though: * *United Kingdom* - London is disproportionately powerful in financial terms, which means that a whole lot of people are heavily involved in financial trading. This sector would collapse without digital support, especially if other nations are able to take up the slack, although the global nature of a lot of these high level transactions would cause knock on effects across the rest of the world. Small villages and towns cope somewhat better - there are several schemes where regional "currencies", linked to the Pound are in use, and these could relatively easily expand. They tend to aim to keep money within the local area, and cash transactions are essentially unaffected. Cities and large towns, which are more reliant on national or international businesses are hit harder. Due to the daily requirements of life, people in these areas are more likely to operate "cashless" - using card payments, mobile phone payments, and electronically controlled transport payment systems. Without the banking systems working, they effectively have no way to obtain funds, even if they were previously fairly well off financially. City dwellers also tend to have less contact with neighbours, so may feel less able to approach others for trades of useful goods (e.g. vegetables grown in gardens or similar). * *USA* - This is essentially one of the scenarios "preppers" prep for, so in areas where large numbers of people are prepping, there is likely to be resigned acceptance. The USA is even more biased towards city living than the UK in many regions, so suffers similarly to the UK. There are also various areas where there are closed economies which don't intersect particularly with large finance - immigrant communities where most money circulates within a fixed group, as with the regional currencies in the UK. * *Somalia* - Somalia doesn't really have a financial sector, and most payments, even large ones, are cash based, due to lack of trust in banking systems in a country with a barely functional government. Essentially, life goes on - hardly anyone notices. * *China* - Large financial sector, which is likely to collapse, but also a very controlling government, relative to the UK (in theory), which has a lot more say in how businesses within the country work. In theory, it would be able to enforce cash transactions for day-to-day life, and then work to support critical businesses. This might involve military law, enforcing work in return for basics of living such as food and shelter, or a wholesale return to communist ideals. * *North Korea* - No difference for most people, with the rulers being the only ones affected. * *Switzerland* - It's essentially a country of London. Collapse. [Answer] A major hacking compromise would not result in *all* funds becoming frozen - while a financial institution may freeze most of its operations (especially if some state of emergency is legally declared) until it gets some recovery done, it will be able to handle any transactions that it deems sufficiently important in the same manner as in their "usual" disaster recovery procedures on how to do (some of) work based on paper if i.e. the IT systems are completely unavailable due to communications or power outages or some other issues. That wouldn't work on all or even most transactions, but it would be quite feasible to arrange, for example, that all your corporate customers get deliveries of cash for paying out salaries simply based on existing legal agreements (in paper files) even if no account information is available or trustworthy. Such backup procedures also exist for any serious transaction system - for example, some years ago I worked on a (non-US) ACH-like system and we had clear pre-arranged business contingency procedures that would also work without any digital trust by exchanging paper documents - it would be rather expensive and labour intensive, but it would work and allow for partial recovery (i.e., not the full number of transactions, but including all the larger and the more important ones) within hours assuming that there's not some other disaster that doesn't allow you to communicate with your employees, or move people/couriers around the city. A more realistic effect would be an immediate credit crunch as every institution is afraid about other institutions liquidity and solvency - similar to immediate aftermath of the Lehman Brothers collapse. It would result in an economic crisis and *hurt* a lot of businesses, but it wouldn't result in stopping economics or destroying a lot of businesses. [Answer] [*I, for one, welcome our new BitCoin overlords, and would like to remind them that I can be helpful in rounding up others to toil in their crypto mining pools.*](https://www.youtube.com/watch?v=8lcUHQYhPTE) That's only slightly glib, in that what you're asking about has happened to varying degrees in various countries around the world, both historically and in modern times. Your scenario is fundamentally the same as other historical financial system and governmental collapses, only with the slight variation that it's an electronic financial system. The classic textbook example of a total financial collapse is [hyperinflation in the Weimar Republic](https://en.wikipedia.org/wiki/Hyperinflation_in_the_Weimar_Republic) during the interwar period. The Weimar Germans had it especially bad because they really didn't have any options other than using the worthless paper currency, which by the end was being burned for heat, used as wallpaper, and generally used as anything but currency. The best modern example of a total financial system collapse is [Zimbabwe](https://en.wikipedia.org/wiki/Hyperinflation_in_Zimbabwe), 1990's through 2015. (`Zimbabwe's peak month of inflation is estimated at 79.6 billion percent in mid-November 2008`, which works out to ***30,700% inflation per second***), and they still... exist, and in largely the same horrible mess they've always been in. A far cry from total chaos or a societal collapse. When a financial system collapses, people just use something else as currency, and ultimately the result is that the government-issued currency becomes completely useless, is not used, is no longer printed, and people standardize on something or somethings else to use as currency. Maybe, long term, the government is able to re-establish government-backed fiat currency, but if not, and until they do, people rely on other nations' currencies, and traditional "value stores" like gold. The current situation in Argentina, post-Chavez is instructive, as it is likely similar to what we could expect from your scenario for any given society, not counting any international economic repercussions or fallout. Bad, painful, but far from total chaos. Society doesn't collapse. Argentinians now are using currencies from other countries and commodities like gold as currency, rather than untrusted, mostly useless state currency. (Even with the government largely criminalizing the use of foreign currency and mandating obscenely bad official exchange rates.) Someone or something destroys the financial world every 10 to 15 years, but we recover and carry on every time anyway. Most recently, it was the [sub-prime mortgage fiasco](https://en.wikipedia.org/wiki/Subprime_mortgage_crisis) that wiped out tens of trillions of dollars from the US economy. Before that it was the dot com bubble bursting. (Twice, actually, late 90's and again in the early 2000's). Before that it was the banking collapse in the 80's, before that the OPEC embargo of the 70's, and so on, probably going all the way back to the beginning of history or so. Every decade or so the world gets destroyed, and every time we recover, rebuild, and prepare to do it all over again. So, let's pick the US for our total financial collapse, as it's probably the worst case for global implications and repercussions as far as how financial collapse in a single country would ripple out to the rest of the world. Frankly, it doesn't make much difference how it happens... whether it's hackers, war or invisible pink unicorns, recovery looks basically the same, and it's basically the same thing that happened when banksters destroyed the world 8 years ago, dot com companies and moron financial analysts destroyed it before that, and so on. In what ended up being massively longer than I'd like, you can see my analysis of what implications a US financial system collapse would have, below, and there's simply nothing there that's unprecedented. It's all stuff we've survived in the past, so I see no reason that we wouldn't survive it again. 1. US dollars become worthless. This is brutally painful for Americans and wipes out tens of trillions of dollars worth of wealth in America alone, the American economy sinks further and faster than it did in the Great Depression. Within the US, this creates a societal reordering, rather than a societal collapse. The current wealthy elite whose fortunes are based on the newly worthless US financial system and fiat currency go from billionaire to broke overnight. (Just as happened in the Great Depression and the Black Tuesday 1929 stock market crash.) People fortunate enough to have substantial holdings of what replaces USD become the new wealthy elite. At this time, replacements for USD would likely be precious metals commodities (gold in particular), GBP or Euros, and people with significant numbers of blockchain-based crypto currency (BitCoins, LiteCoins, etc). The existence and current semi-accepted state of crypto currency is a new phenomenon, yet it's all but guaranteed that crypto currency will be a significantly dominant replacement for whatever government-backed currency gets wiped out in any future financial collapse - it has all the advantages of government-backed, fiat currency (and some significant advantages fiat currency doesn't), but most significantly for a financial collapse situation, is completely unrelated to the current financial system or government fiat currency. 2. Countries that are major global trading partners with the US suffer severe economic destruction as collateral damage from the US financial collapse, of course. Countries who use US dollars as a defacto currency will be similarly devastated, and find themselves turning to similar replacement currencies as seen in the US. Countries that peg their currencies to a rate based on US currencies experience a brief and unpleasant currency correction shock, but are not too bad off. Even the countries that artificially suppresses or elevate their own currency evaluation via this USD linkage don't suffer significant long-term repercussions, since they just switch to pegging against the Euro instead. 3. China would end up suffering almost as much economic damage as America in the most optimistic analysis, with a significant chance of ending up suffering even more from a US financial system collapse than the US would. China owns massive amounts of American private and sovereign bonds (debt), which is now all gone. Use of monetary policy and a pegging of the Yuan to USD at an artificially low rate has historically created large economic growth based on exports to the US, at a cost of making the Chinese economy dependent on those exports. The US financial collapse wipes out US demand for Chinese goods, dragging down the Chinese economy with it. The massive loss of wealth for both Chinese companies and government from newly worthless US debt causes panicked stock sales on a large scale. The Chinese stock market is currently heavily artificially inflated by the Chinese state, which no longer has the ability to continue the charade. The Chinese suffer a market crash as bad as, or worse than, the Black Tuesday market crash of 1929 in the US. Existing concerns about overstatement of Chinese economic growth by their state agencies amplify the stock market crash and result in Chinese economic contraction on a scale not seen in major economies since the Great Depression. State controls on the Chinese economy go into overdrive, in an attempt to prevent total economic collapse, but fail, because the foundations of the Chinese economy (ownership of US debt, exports to the US at highly favorable currency rates, an artificially inflated stock market) have been ripped down by the US financial collapse. There is a significant possibility that expensive, mostly empty cities built by state planners will need to emptied back into the rural areas as a result of the economic collapse, in [a reverse-flow replay of the Mao-era "Great Leaps Forward"](https://en.wikipedia.org/wiki/Great_Leap_Forward#Famine_deaths). This would have the effect of collapsing real estate prices, which would further exacerbate the economic and stock market crashes. China likely has no possible short term solution or mitigation to their economic implosion. 4. The EU and non-EU European countries go into economic depression, but not devastatingly so. Like everyone else, China and the US comprise a significant part of their economies, but not enough to risk financial or societal collapse as a result. Other "1st world"/"industrialized"/well-off countries outside of the EU (South Korea, Japan, Australia, etc.) end up in a similar boat as the EU, with varying levels of economic depression and wealth destruction as a result of the collapses in the US and China that comprise a significant part of their economies. All these economies will be growing again inside 2 or 3 years. 5. India gets hit a bit worse in absolute terms than the EU and "industrialized" countries, due to their industrialization efforts being financed significantly by the US and China, as well as the loss of those markets for their good and services. In relative terms, the collapse of China is advantageous to them. India supplants China as the world's largest, fastest growing "developing" economy. With China's economy in ruins, India is now the country that will emerge as the world's next military and economic superpower. Brazil is in a similar position to India economically. In absolute terms, things are a bit worse for them, in relative terms, China's fall means that Brazil joins India and Japan in the top 5 world economies, when counting the EU as a single economy. (EU - #1, US - #2 probably, #3 possibly, Japan - #2 or #3, India - #4 or #5, Brazil #5 or #4. China probably drops to #6, followed by Russia in #7.) 6. Africa, Russia, and Central and South America are hit hard by the collapse of China and/or America, and the resulting loss of trading partners, investment dollars and/or foreign aid/financial loans, but they're all economic disaster areas anyway, so relatively speaking, the world doesn't look too much different to them. 7. The impact on the Middle East and the OPEC oil producing countries is highly variable, depending on which specific country you look at. Oil is still in high demand. The devastated US and Chinese and depressed EU economy sees global demand for oil drop 20 to 35%, but this is not crippling to most OPEC countries. Middle Eastern countries that are warzones or otherwise have no functional government control remain as disaster zones. ISIS likely tries expand, forcing direct military action by Israel and Turkey, in conjunction with any governments currently left standing in the area. Similar dynamic for the other Islamist groups operating in failed-state regions of the Middle East. As the two stable powers remaining in the region, Israel and Turkey likely expand their political and military influence accordingly. [The House of Saud](https://en.wikipedia.org/wiki/House_of_Saud) falls to internal parties or external forces who set up local puppets, as the US is no longer able to prop them up. Probable fractured-state or failed-state dynamic in the Arabian peninsula as a result. 8. Decreased global oil demand hurts Iran more than most. With US and European influence and force projection capabilities in the region severely hampered, there a strong possibility of multiple flashpoints between Iran and any standing Sunni Arab states, Iran and Israel as well as Iran and Pakistan. If so, India looks to exert influence on its periphery against Iran, possibly warming Indian-Pakistani relations. North Korea collapses with the loss of their Chinese patron, resulting in several million starvation deaths in the first year. Korean unification under South Korea likely, after bloody failed-state dynamic in North Korea, as DPRK military fails to maintain control with Chinese patronage. Probable cooperation between South Korea and Japan substantially warms relations between the two. So... a lot people are ruined, a lot of people die, some countries get wiped off the map or split into pieces. Alliances shift, wars and insurrections occur. Underneath it all, normal people keep doing what they have to do as best they can do it to survive and put food on their table. AKA, the whole history of the world since the dawn of time or so. [Answer] Revision to more traditional means of commerce would follow such a catastrophe. In societies with traditional trust mechanisms, these would come back as the default, for example traditional Chinese culture is based on trust within the family unit, while American society trust is based on "being a man of your word". So many projects, corporations and even units of government would devolve to meet the requirements of the basic "trust units". Things would become much smaller, and while small projects could go quickly, larger projects would have to be either recast as collections of small units with interfaces between trusted people, be forced to move much more slowly as physical meetings and "sneakernet" connections are arranged or simply abandoned altogether. Governments would become much more important and perhaps powerful at the municipal and town levels, while administrative units like Provinces and States become less so, and national level governments become stripped of many of their powers by default, as people refuse to deal with them over the trust issue. Even internal government functions will become difficult to impossible as bureaucracies internal functions are slowed or severed due to lack of trust (and endless committee meetings and movement of bureaucrats will paralyze whatever functioning is left). There is obviously going to be major attempts by governments and bureaucrats to attempt to keep their existing perques and power, by force if necessary, but the same trust mechanisms which allowed the expansion of modern commerce and industry also underly the ability of large governments and the Administrative state to function. While it might be easy to call out the Army to suppress an area, if the soldiers cannot be paid, they are not going to be as inclined to follow orders. Populations dependent of government welfare like food stamps will also be uncontrollable if their benefits are not being provided. So an overall reordering of society into smaller units which can provide internal trust and communications between trusted members is going to be the result of this catastrophe. [Answer] By using physical documents, couriers and face-to-face meetings (aka the [sneakernet](https://en.wikipedia.org/wiki/Sneakernet)). This would slow things down considerably, as meetings would have to be arranged, and documents/couriers vetted. However, most of these transactions could have time limits applied: if the courier does not arrive within a certain amount of time, the transaction is rolled back by default. A side-effect is possibly faster transmission, especially for very large files (never underestimate the bandwidth of a station wagon full of USB drives). ]
[Question] [ As discussed here: [How would a Reflecting-Oven-Jay Evolve?](https://worldbuilding.stackexchange.com/questions/15061/how-would-a-reflecting-oven-jay-evolve) > > The Reflecting-oven-Jay > > > This is a small African predatory bird with a perfectly smooth set of wings with an area of ~100 cm2, so maybe the size of a pigeon. It hunts in large flocks, around 10,000 birds to a group (there are plenty of real birds that form flocks this size). Using some basic multiplication, this flock can focus about 130 kW of sunlight. The flock decides to kill and eat an elephant, who has a metabolism of around 3000 watts and already has to work to keep cool on a warm day (heat sink ears, spraying water on self, etc). By spreading out and focusing sunlight on the elephant, the birds totally overwhelm the elephants ability to cool itself, raising its body temperature by about a degree Celsius every 2 minutes (130 kW / 4 tons\*specific heat of water), leading to slow heatstroke and death. Divided evenly, there's a lb of meat for every bird in the flock, a huge windfall, sustaining the group though any cloudy days until the next kill. > > > Assuming it evolved as described in the answers to that question, is this actually viable? We've seen birds self-organize into vast flocks so creating a formation should be achievable but: How much light could an individual Jay actually concentrate into an area? Can the flock manage to scale that up to a sufficient power to overheat the target? Do the birds need to land and use their wings and tails as reflectors (in which case they'd need the right shaped for the land surface) or can they do this while in flight. While in flight would be ideal as it makes them considerably more terrifying. On the bright side (all puns intended) the fact that they are doing this in an already extremely hot area and aiming at animals already coping with high temperatures does count in their favor. They don't need to raise the temperature very much. [Answer] My attempt doesn't truly answer if it is feasible or not, but it does try to come up with a *believable* solution. **The problem is flight** If this bird indeed developed this behavior through survival, we can almost immediately discard any notion of it using it's reflective feathers while on the ground. Not that birds are necessarily all slow on the ground, some are very fast (ostriches), but from an evolutionary historical standpoint, birds than are very fast on the ground, aren't in the air, and vice-versa. Not to mention ground predators don't necessarily need to see as much in order to pounce on their prey if it's on the ground. So our bird is a good *flyer*. But how can a flying bird reflect sunlight. A bird in flight will normally hold itself almost horizontally. Meaning feathers on its back, wings, head, and tail would reflect light upwards (mostly) and the ones underneath would have no sunlight to reflect. This makes directing light reflection rather inefficient for most. **A bird with unusual flight abilities** The hummingbird is the only bird I know of that can hover. (You can read up on it on Wikipedia). It also needs huge amounts of food and is basically constantly fighting starvation because it spends too much energy but let's get back to the question at hand. **Hovering** allows for more precise placement in a defined space. It also allows the bird to position itself much more *vertically*, meaning there's an actual non-dynamic surface (belly or back&head) that can now reflect effectively sunlight towards *something*. Add the ability to place itself properly and a flock of hovering birds could form some kind of a reflective panel formation, using up to 20-30% (invented number) of their surface to reflect light. [Answer] Another idea lacking on information about how feasible it is. Imagine if the birds had tails like a peacock branching behind them. Except less wispy, more reflective. ![White Peacock](https://i.stack.imgur.com/N3sGx.jpg) You could make them ground based, but the scenario seems to indicate that flying is better. So instead, for birds in flight, imagine if the tail moves not only up or down, but can tilt from side to side. This will interfere with their flying, so either the wings need to overcome the drag from the tail or the bird actually glides from its tail (which overcomes the drag from the wings) while using its wings to reflect the light, though that causes some amusing images of gliding birds in my mind. [Answer] Mythbusters did an episode trying to use solar power to repel a pirate ship (at the behest of President Obama). They found one *major* challenge is aiming. If you're the only one putting a jittery bright light on the target, it's easy to see your errors and correct them. With 10,000 jittery bright lights, it becomes hard to determine which one is yours, and good aim was very difficult. They solved it by putting a mesh in front of the mirror-holders so that each mirror holder could see where *their* light hit the mesh, and extrapolate out to the ship. Accordingly,to aim, the oven-jay would probably need to have a special limb which reaches out in below the oven-jay and acts like a targeting recticle (or like Mythbuster's mesh). The oven jay would need to calibrate this geometric structure, and then ensure it doesn't change during flight (which is not easy for any organic structure). Also worth noting would be that the path of an oven-jay would be very predictable during attack, because it would have to hold its wings at a very exacting angle. Oven-jays would have to fear predators from above while they are attacking. An attack could take a very long time. Consider the heat of 13 1kW space heaters, and think about how long that would have to be focused to actually kill an elephant. The ovenjays are only 10x faster than that. [Answer] They could be a two-step reflector akin to a mirror telescope: the huge swarm flies below, reflecting and focussing the sunlight upwards, and a small swarm flies above, reflecting and further focussing the light through a small hole in the lower swarm. They could circle all the while, which would also fit the inclination needed for the focussing [![enter image description here](https://i.stack.imgur.com/IX8u5.png)](https://i.stack.imgur.com/IX8u5.png) Note that both mirrors would be bowls, which would roughly fit the way the birds would need to angle their wings for flying in circles. The different mirroring might be sexual dimorphism, one gender is mirrored on the upside (and therefore make up the lower mirror), and one gender would be mirrored on the underside to populate the upper mirror. The leisurely circling would also alleviate the need for perfect focus: They could keep this up for hours, while the elefant would exert itself trying to get away. I thought about the circling and the angles of the wings some more: If the oven-jays fly in circles around the axis of the telescope, the wing angles (angle of bird vs. horizontal) for birds near the axis would be more greater (because the curvature of the flightpath would be tighter), while the mirror actually needs to be more horizontal there. This could be solved by having them all fly in similar ellipses, thereby setting the parts of the flightpath with higher curvature (and therefore steeper wing-angling) farther from the axis, and the parts with less curve and less wing-angling nearer to the axis. Center of the ellipse would be the axis. [![Flight-paths seen from above](https://i.stack.imgur.com/RzsW5.jpg)](https://i.stack.imgur.com/RzsW5.jpg) Pictured: Flightpaths as seen from above [Answer] No, as written it does not work, spacemonkey is right flying and reflecting do not realistically combine. And even in ground you would probably need to be stationary for some time, a state also known as "predator attractor". I could expand on what spacemonkey explains about the reasons, but instead I'll just tweak the \*\*\*\*\*\* birds to something that might work and maybe even evolve. It is all about heat management. Assume a bird that evolves to reflect as much heat as it can. Make the feathers in wings transparent to sunlight in a further effort to reduce heat while flying. Would also give the bird lower visual profile while flying, making it harder to recognize by both predators and prey. And even if the predators sees the bird making the wings harder to makes predicting its evasions harder. Now imagine a huge flock of these birds. Sunlight streams down thru the transparent wings of the flock or reflects off their white bodies. It hits the ground below and a large part of it converts to heat. But the flock reflects the resulting infra-red back creating essentially a mobile greenhouse under it. This behaviour could evolve since the resulting updraft would make flying easier, if the bird forms flocks for some other reasons. And yes being surrounded by these birds would make you hot, provided it was tropical midday. So heat exhaustion might happen and be usable as weapon. Large flocks of these birds could drive off competition from carrion simply by hovering around until the competitor must leave. From that it is a short step to using the the heat to create new carrion. The special effect is very different from what you probably wanted, though. [Answer] An idea not touched upon yet is **flying in a group around the target**. While flying light can easily bounce off the wings and make the whole idea of focusing the light into the target hard. Standing on the ground to do the same is also just as hard due to threat from predators. So my take on it would be: the **back and tail feathers are reflective and this focuses the light onto the target as they circle it**. So, no hovering is involved and all light should, if at the correct angle, focus into the target as they go around it. [Answer] The birds won't be able to stalk and kill a large beast with their ability. Aiming will be nearly impossible during flight, and landing on the target allows for many ways of retalition. Also, by hitting an elephant by about two degrees every minute, the elephant will have plenty of time to hide under the shade of trees, or to go into a river where the water will be a heat sink. Your birds could hunt in some other way. In Australia every living creature is trying to kill every other living creature in one way or another, and sometimes they get creative. Australian birds of prey [have taken a page from Cave Johnson and learned to burn other animals' houses down](http://www.iflscience.com/plants-and-animals/australian-birds-of-prey-have-harnessed-the-use-of-fire-to-flush-out-their-prey/). Your birds could do the same thing, but they don't need to find a fire. They can make their own. Just burn the savannah high grass. This has a lot of advantages: * A single bird can start a fire that will spread through a large area; * Not only there will be more meat than the birds can eat, it will be cooked, making it easier to digest. Same thing happened with hominids when our ancestors tamed fire; * This method of hunting is delightful to watch (I am not a pyromaniac). ]
[Question] [ **This question already has answers here**: [Where would an identity implant be implanted in the body? And what would make it secure?](/questions/54211/where-would-an-identity-implant-be-implanted-in-the-body-and-what-would-make-it) (12 answers) Closed 6 years ago. In Futurama every person has a chip implanted with their personal details and a predetermined job. On the show the chip seems to be implanted in to one of their hands, and is easily removable. Where would be the best place to have such a chip installed at birth that would be extremely difficult to remove? [Answer] **Inside the skull** When babies are, well, babies, the skull is actually rather soft. Right in the inside of the skull would make a chip very hard to remove, but not incredibly difficult to insert. [Answer] **Near an Important Artery** As a baby, arteries are much smaller and much more accessible to surgeons. A tiny incision could take a chip right close to major arteries with little risk. In the future the tiny chip remains tiny, while these major arteries grow considerably. It would take a skilled surgeon to remove the chip without damaging these vital arteries. The authority responsible for placing the chip could also vary the locations of these chips to hit various arteries, so finding its location would factor into the cost of having it removed. **Within Bone** Putting the chip inside of a subjects bones could also do the trick. Removing it would be incredibly painful (think bone marrow transplant) and costly. There are also many bones in the body, so this also provides an opportunity for varying the chip location. **The Real Issue** Regardless, if the chips can be inserted by a skilled surgeon, there must be the possibility of someone with similar expertise removing it. The real deterrent would be laws against its removal with regular checks (and likely strict punishment), and difficulty of removal. Making the actual procedure for removal incredibly difficult and expensive allows only the most wealthy or skilled to actually remove the chip. [Answer] Rabbit's suggestion of inside the skull is good, another possibility would be in the chest cavity. It could be inserted with a thick needle and the surgery to remove it is actually more difficult than opening the skull (if you don't get into the brain itself). You have to cut through muscle and bone and avoid a bunch of blood vessels that you really don't want to mess with if you don't know what you are doing. [Answer] **Make them breath it in** If your chip is going to be around similar dimensions to that in Futurama you could make people just breath it in. It will end up somewhere inside the lungs where it'll be nigh impossible to remove without extensive surgery. The added bonus is that this way allows to even chip people that were born off the grid or outside your sphere of influence. [Answer] So you want the chip to be hard to remove. Right. **Does it matter if the subject survives the retrieval?** --- ## No Get me that chip, I don't care. Put it somewhere accessible, but hardish to get to if the subject does not want you to. Go for between the shoulder blades if you want the least hassle. Somewhere under the skin in the breast area for visibility. Maybe in the buttocks? (not many nerves there) --- ## Yes I don't want to hurt or endanger you. And seeing you got your chip implanted into one of the upper [vertebra](https://en.wikipedia.org/wiki/Vertebra), as in, it's part of the bone, it will be very hard to remove without complications. (See Logans [answer](https://worldbuilding.stackexchange.com/a/81610/34012) for some ideas. Or in [skull](https://worldbuilding.stackexchange.com/a/81607/34012) like Rabbit says.) [Answer] Here's a radical concept; nanobots. These nanobots would be injected into the blood stream and use genetic information as a biological identifier and broadcast relevant information to the parties with access to the broadcast codes. There would only be a few nanobots and they wouldn't need to store very much information. In fact, the data could be spread across a few bots if data storage is a problem. The reason why this is an excellent option is because there would be no way of knowing where in the blood stream the nanobots are hanging out. While this isn't a chip per se, it serves the same purpose and is basically a chip that was chopped into a bunch of tiny pieces and still works. [Answer] I think something that could be quite important to think about here is also that you don't want the populace to lose the chips implanted inside of them. There are quite a few job or hobby related incidents in which people lose digits are even entire limbs, like their legs or arms. Because of that, it could theoretically be considered a bad choice to place the chips here, unless of course you go with the idea that the government predetermines the chipped people's jobs as well. In that case, you could decide that people in low risk jobs could get implanted in their arms or legs, and other people could get implanted somewhere else. It's that "somewhere else" bit that gets even more opinionated. Like others have stated, while it would be arguably easy to place a chip inside the head of a baby, it wouldn't necessarily be easy to pull the chips out later in life. A chip placed in front of, or near, a vital organ could result in pieces of the chip doing damage to the organs themselves if the chipped person is ever shot or stabbed in that area. Likewise, putting the chip in other areas, like under the arms or lower belly area could make sitting down or becoming overweight quite uncomfortable, depending on the size of the chip. Putting it in the back could make sleeping harder. I suppose everything comes down to the size of the chip, whether or not it has to be removed in order to be verified (could officials simply scan the chip through the skin with an electronic device?), and how visible it must remain at all times. However, as a side note I'd like to point to two chip-ish instances in video games: The location of Cortana in Master Chief's head in Halo, and the bar code on the back of Hitman's head in Hitman. Depending on your own rules, this area of the head could be a viable place to put the chip. There's a lot of ways to play with that idea. Put a small disk tray like device back there, or force the populace to keep their heads shaved. Overall, I'd still say that this can be kind of a difficult question to answer with so many variables. [Answer] ## Put it inside the brain A skilled surgeon can remove and replace almost any single organ or tissue of the body, but the brain is what make you who you are. Yes we do have a number of skilled neurosurgeons in the world, but they are few and far between; and even if you could convince a sufficiently skilled surgeon to do it, I think the downside (brain damage) would be a pretty good deterrent against removing the chip. Putting a chip inside a child's brain would carry risk, but if performed correctly (which standardizing would likely ensure) should produce little to no damage. The brain is surprisingly resilient in recovering from damage, as shown in people recovering from severe brain injuries, but who would want to go under surgery to remove a chip, knowing that the person waking up wasn't going to exactly be you. ]
[Question] [ In sci-fi movies and tv shows, English happens to be the Lingua Franca of most alien civilisations humans come into contact with. Even upon first contact. The obvious reason for this is that these movies are largely produced to be shown to English speaking audiences. Lets assume there are many planets in our galaxy that are inhabited by intelligent beings like our own, but due to the different physical characteristics of these planets, they posses quite different biological characteristics Lets say various Alien civilisations communicate by: Whistling, grunting, radio-waves, exchanging proteins, exchanging electronic data etc etc... What would we humans as explorers need to do to establish diplomatic communications with such societies? Could a lingua franca be possible on a galactic scale? [Answer] There are two interlinked problems to a lingua franca that works for multiple sentient species. One is, as you have said, that the lingua franca would have to work for species whose means of speech varied between "Whistling, grunting, radio-waves, exchanging proteins, exchanging electronic data etc etc..." The other problem is deeper and more difficult. Problem number one could be dealt with by having the *common* part of the lingua franca be at the level of conceptual structures; the part of grammar dealing with basic classification of nouns and verbs and adjectives - or something even more universal than these divisions. Then on top of that there would be the actual means of speech, which might vary between species but could probably be translated by computers or people given that the grammar was already the same. There is a real life example of this sort of thing now. As you probably know, the various sign languages used by the deaf, such as British Sign Language and American Sign Language, are languages with a grammar very different from the spoken language (English) in the same territories. For instance sign languages, being received visually, often use the fact that information can be relayed from the face and the position of the hands *simultaneously*. However when people go deaf later in life they often find it hard to pick up a whole new language such as BSL or ASL, so they use Signed English, when each word is signed in the order that it would be spoken in English. It is "clunky" compared to the true sign language because the necessarily sequential nature of a spoken language adapts badly to the more "parallel" nature of a gestural language. But it is easy to learn for a native English speaker and works as a sort of lingua franca. Problem number two is more profound - what if the thought of aliens is so, well, alien that we simply cannot find common concepts? We could only establish whether an alien species shared enough common concepts to build a lingua franca between them and us by trial and error. *We* might be spared the bother if other established spacefaring species interacting with each other had already done most of the work for us. All we would need to do was add the specific English / Mandarin / Hindi or other local surface layer to the off-the-shelf translation machine that comes with the Galactic Federation welcome pack. [Answer] If faster-than-light travel is possible, then a galactic *lingua franca* is possible. Consider written and spoken English: the language is the same, despite being encoded using two very different sets of symbols (marks on paper vs. variations in air pressure). A galactic *lingua franca* simply requires that your species establish a transformation between a set of symbols that you understand, and a set of symbols that some other party uses. If faster-than-light travel is impossible, then a *lingua franca* is, at best, highly improbable. Languages evolve, even trade languages that nobody uses as a first language. Given a minimum edge-to-edge travel time of 100,000 years, the language will have shifted so much that effectively each contact will be a first contact, at least from a linguistic standpoint. [Answer] There is a lot of philosophy involved here, so you could start out by reading Wittgenstein to get the basics, but that's a lot of work and I don't know that I understand most of it myself, so I'm not going to get too deeply involved on that side of things, so I'm going to talk about my day job instead: Assumption 1: We might expect that spacefaring races would develop machine computation or something like it. Assumption 2: We might expect that early communication avenues between alien species to be related to scientific enquiry and trade. Obviously, both are open to challenge, but starting with them offers the interesting proposition that rather than a language as such, the starting point for communication might be a standard data interchange format rather than something equivalent to our spoken languages. This could begin from universal mathematical concepts so that newcomers to it would be able to decode it in a simple way and then allow data interchange in more sophisticated but fundamentally literal ways - quantities, images and so on. This interchange language could then be adapted to allow translation via whatever type of interface the users of the language needed, so we might put it on screen or turn it into sound, the Xanziklargians will convert it into pheromones while the Mn''z' will convert the data into gamma ray pulses and the Aeiazima Windwraiths turn it into fine threads of warm and cold nitrogen. Everyone's translation software is different but the data they are translating is standard. The language may develop extensions that allow more detailed communication between species which have concepts and ideas in common, but the basic interchange format will need to be limited if it is to be universal. The conflict between universality and detail makes this a very interesting area to contemplate. [Answer] ***If*** contact is possible, a [***Lingua Franca***](http://en.wikipedia.org/wiki/Lingua_franca) is inevitable. Historically speaking this happened whenever more than 2-3 different cultures were able to communicate. Trade, exchange of information, many reasons drive the need for contact. A single communal language is the common answer. Step one in diplomatic contact is to learn to communicate and to build trust. [Answer] It is hard to imagine a space faring race not being able to see or have a written language. So while they may have some means of communication we are not able to see/hear etc., it should be possible to be able to communicate using some sort of visual written set. Now off topic SETI has been listening for some time now and has heard nothing. That means that there has been nothing in range that has some sort of communication we would understand and that means no alien races that are close by to us. There may be other intelligent life in the universe but nothing close. If faster-than-light travel is possible is it FAR more likely that someone would just show up or we would find them long before SETI would hear anything. [Answer] First of all,Aliens will probably have diffrent vocal cords and eyes(most of them,i believe)so the idea that English could be a Lingua Franca is kinda naive..I'm almost certain (and i have reasons to believe it) that there are diffrent "inteligences",not just human inteligence.And diffrent instincts,so what follows:diffrent kind of logic. There are two solutions to your problem: Telepathy I'm not talking about any mumbo jumbo or Jedi Knights,but mind reading technology that is theoretically possible.A device could read your brain waves and transmit it (like a phone call of sorts)to another device of alien lifeforms.This way you could "see" or "feel" what they want to communicate.There are two diffrent versions: 1.Translation of brainwaves into words/sounds of an alien,something like a speaker that will tell an Alien what you thought of.It may be problematic:remember,aliens may be asexual,have diffrent genders,or just completely diffrent set of instincts,so it may still sound nonsensical for them.I guess it also depend on the translation devices.Would they be able to translate everything into another laungage ?The answer is yes when the type of species is similar to humans.We may use similar things here on Earth in 100-200 years or so. 2.Translations of "feelings".This is probably far-fetched,and i cannot see how it would work from the scientific/Engineering perspective.However,when this mind reading or "telepathic" technology is perfected,someone's thoughts could be "translated" into visions or feelings.You could suddenly underrstand what an alien wants and feels like about particular subject.If you want to make it cooler and more mysterious,it could work like a VR of sorts.You would be taken to a virtual world where you could experience the same senses,smells,pain etc.This way you could really understand other species. Lets call those devices "telephators".Also,note that this all assumes that FTL travel is possible.Without it,it is impossible to keep track of the telephator technology,as those devices need to be compatible with each other.But with FTL a common system could be used.You could think of a fancy name for it and it would work like a "telephatic internet"of sorts. Prothean Laungage Inspired by a videogame called "Mass Effect".Imagine an ancient civilisation that has spread all over the galaxy and has left structures with a written laungage(or something else)in many star systems.Because it is a dead laungage,it never changes,it is used in interspecies communication and it is "standarized"for this purpose,and no one uses it in daily life.You get the picture. This version assumes that Alien species are at least remotely similar to homo sapiens,and even when they have 6 hands or tentacles ,they can at least see a writing system.Note that an Alphabet, Sylabic Alphabet or Abjad is a poor choice:it has to be an iconographic/logographic system like Egyptian hieroglyphs or Chinese Hanzi,where every symbol has a meaning.Memorizing like 100 000 diffrent symbols poses no chalenge for human-like civilization,as you have computers everywhere and they will be able to upload new knowledge straight into their brain implants (or AR glasses or whatever). If you want your laungage to be spoken,this complicated things.Inn this situation i would go for a Japanese-inspired way of writing.In Japanese,you can write everything in two diffrent versions of "Kana".In essence,they are syllabic Alpabets (one symbol,one syllable)Katakana is used for loan words ,foreign names,countries,plants and animals.Hiragana is used for everything that cant be written with Kanji (Chinese symbols used for Japanese).So majority of words that you see in this laungage are written with kanji,but in the same line you see a lot of Kana as well. For our purposes,Kanji-like system could be used for species that want/must communicate only through written laungage (they could call those symbols in their own respective laungages,like Chinese read kanji diffrently than Japanese).And kana-like system for sounds....However,it still leaves the problem of deciphering those sounds when we first see them.An recording or some "biological scheme"(a plan of their bodies/genes that would show us how their communication worked)is needed. In theory,other ways of communication can be found in those "prothean ruins".If a lot of these "dicitionaires"were spread across the Milky Way,they would be seen as the best standarized Lingua Franca (or a set of Lingua francas). Later if i have more time i will review this answer in case i made some spelling mistakes,and maybe i will add an idea or two. ]
[Question] [ While the reasons for it's existence do not matter as it is part of an artificially created planet, I am curious if a lapis lazuli island would be able to survive erosion and support Earth-like life? Are there any new dangers that would come about from this kind of environment? What kind of adaptions would be likely in such a place? [Answer] # Its not too much different from obsidian First off, lapis lazuli is a gemstone mostly formed of the mineral [lazurite](https://en.wikipedia.org/wiki/Lazurite). Lazurite has the same blue appearance as lapis lazuli, so it might be more reasonable (and accurate) to say that your island is made of lazurite. Based on lazurite's hardness (5-5.5 on the Mohs scale) and density (~2400 kg/m$^2$); it probably wouldn't act that much differently from obsidian (hardness 5-6, density ~2400 kg/m$^2$). Obsidian lava flows are not too inhospitable for life, other than the fact that they are bare rock. There is plenty of documentation about how obsidian lava flows can be overgrown with plants in a matter of decades. Obviously, a primary difference between lazurite and obsidian that the soil derived from this island would be blue. Ground up lapis lazuli is an expensive painting pigment called [ultramarine](https://en.wikipedia.org/wiki/Ultramarine); your islands soil would be pigment mixed with organic matter. Lazurite has an interesting mix of minerals in it, with sodium, calcium, and sulfate content that will be good for plants. However, without phosphates and nitrates, it might be a hard for plants to get a head start. On the other hand, seabird guano's fertilizing properties are primarily in teh form of ammonium nitrate and phosphates. A few hundred thousand years of seabirds nesting on the bare rock might provide all the soil nutriment needed for the place to be over-run with vegetation. I don't see lazurite being called alkali anywhere specifically, but it is a [feldspathoid](https://en.wikipedia.org/wiki/Feldspathoid) mineral, and many of these minerals are alkali. So it seems likely that your soil will have a high pH, which may limit the plants that can colonize. Volcanic derived soils are usually acidic, by contrast. However, in keeping with the seabird island theme, coconut palms will do fine up to pH of 9 (and maybe higher) so plant life would be able to get a start on such an island, even if it has an alkaline soil. ]
[Question] [ I am creating a world where the currency (the only currency) is tablets that dissolve in water to create food. Each tablet provides all of the nutritional needs for an average adult for one day. The gruel doesn't taste particularly good, and the person feels hungry again right away. But, most people rarely eat anything else and the population stays fairly healthy (barring plagues, natural disasters and the occasional war). In most ways, my people have reached a technological level about that of Europe in 1650. The small planet has five island continents (think Australia), with urban centers mostly in the coastal areas. Ocean water is potable, so there is plenty of water for everybody. Unfortunately, there are no aquatic animals. On four of the five continents, most of the land is also very barren. The largely barren continents have pockets of fertile soil, in which various crops can be grown. Every continent also has indigenous large herbivores that eat the few plants that grow wild on that continent, plants that can't be digested by my people. The fifth continent is nearly overgrown with a fast growing plant that is processed to make the tablets. The plants cannot be made to grow anyplace else but on that continent. (There is magic involved here, the nature of which will be revealed towards the end of the story.) The total population on the planet is about 100 million people, with the population pretty evenly split among four of the five continents. Each continent has a monarch and nobility. The monarch and nobles own all of the land and everything it produces including the wild animals (meat). Poaching or stealing of food other than the tablets is punishable by death on all five continents. Three of the continents deal in slaves and on the continent that makes the tablets, almost all of the (grueling) work is done by slaves. The two other continents on which slavery is legal get a lot of tablets in exchange for slaves. Slaves on my planet are slaves for life, as are their progeny (even if the other parent is a free person). Food other than the tablets is scarce. Peasants are lucky to eat real food a few times a week, slaves never do. On the other hand, few nobles have ever tasted tablet gruel. The monarch and most of the nobles on the continent that produces food are extremely rich, extremely powerful, and solidly evil. They like things as they are and want to keep them that way. The fifth continent has its royal family, perhaps 300 rich and powerful nobles, a few thousand pretty darn comfortable peasants, and 50,000 slaves. My story begins at least 150 years later, at the cusp of an industrial revolution. I want the economy of my little planet to have been fairly stable for the past 150 years. It is here that I ask the question: **How can I keep this economy stable for at least 150 years (200 to 250 years is better)?** I figure that the tablets have to be produced at a rate of at least 100 million per day (every day), but the average day will produce enough so that basic necessities can be purchased with small caches of tablets. As a rule, tablets are not hoarded even by the rich. Wealth is accumulated in the form of 'stuff'. Additionally, my people have the sense (or perhaps I can address the issue later as a matter of biology) to keep the population stable. This currency is mostly consumed as quickly as it is "minted". I am not averse to using magic to make things *work*, but I'd like to keep it pretty subtle. Magic is not a day to day concern of people not involved in the manufacture of food tablets. The world has a significant maritime structure that has evolved because of the tablets. It's a small planet, the sailing distance between continents is only a few days. So, 'spreading the wealth' is a non-magical industry important to my people. OH! And as far as my people suspect, they are the only 'intelligent' people in the universe. (Yes, this question was inspired by The Force Awakens.) [Answer] The answer depends on a lot of small details which one might fit into a storyline. From [this Quora answer](https://www.quora.com/What-are-the-characteristics-of-a-good-currency-and-how-does-Bitcoin-compare-to-that) by a former financial adviser: > > 1. Generally Accepted - Many people must accept the money as a settlement of debt or as a discharge of obligation. > 2. Durable - Its quality/value does not deteriorate over time, which is why we do not tend to use food products as money. (*my note: your food does not seem to deteriorate, so I don't think it has a problem with this criteria*) > 3. Divisible - If you divide the money in half, each half should be worth 50% of the whole. This is why we tend not to use diamonds or artwork as money. > 4. Stable/Consistent - The value does not fluctuate substantially with time. > 5. Transportable - It is easy to move from one place to another. > 6. Scarce - It is difficult to acquire. > 7. Easily recognizable - It needs to be obvious what it is, mostly for the purposes of #1. > 8. Difficult to Counterfeit - This mostly has to do with #6. > > > You can analyze your food tablets to see how well they fare, and possibly shape them slightly to better fit that list of requirements. One detail which I think would be very important is looking at how transactions with large numbers of tablets would work. Let's say I work for the nobles, and I have a million dollar helicopter that I want to trade for a piece of rare artwork (okay, maybe those aren't *exactly* 1650's items, but you get the idea). Will I accept, say, 300,000 tablets in exchange for the helicopter and will another party accept 300,000 tablets in exchange for their artwork? This is the "Generally Accepted" criteria listed above. In a more difficult case, I sell my helicopter for 300,000 tablets, but my art vendor has sold the artwork before I could get my hands on it. I now have 300,000 tablets on my hands, enough food for me to eat for 822 years straight! Am I still happy with my trade? Am I comfortable that I can still find ways to get the desired value out of 822 man-years worth of food? If you can convince the readers that the answer is "yes," you are certainly on your way to using food as a currency. Scarcity would be a big deal for this currency. If the nobles start manipulating the food supply, and the poor are dependent on it, it may artificially raise the value of the tablets above their "actual value." This is no problem, as long as the tablets remain scarce. However, if the market is suddenly flooded with tablets when the nobles stop making it artificially scarce, the value of the tablets will plummet. This would actually create a complicated metastability that you would have to deal with: the value of the stockpiles of tablets the nobles have would be worth more as long as the poor are oppressed and hungry. [Answer] Take a look at the [Kokudaka](https://en.wikipedia.org/wiki/Kokudaka) of feudal Japan for a historical example. A landowner's wealth was determined by the amount of *koku* the land could purportedly produce. A *koku* was equivalent to the amount of rice needed to feed a man for a year (about 5 bushels). A smaller unit, the *masu* defined the amount for a day, similar to your tablets. Daimyo's estates had anywhere from 10,000 *koku* to over a million. This is not to say that their wealth was exclusively in rice. Think about how we talk about rich estates as being worth "billions of dollars" as if they could liquidate all of their assets whenever they pleased. A noble's wealth might be defined by the amount of tablets their estate could earn, but in practice the actual food would go towards feeding their subjects while the majority of their wealth would be in goods. The feudal Japanese system also included the [*ryō*](https://en.wikipedia.org/wiki/Ry%C5%8D), a currency unit equivalent to four *koku* (later changed to 1:1). The *ryō* and its lesser denominations were used for everyday spending. So in this way, food was the basis of the currency, but people weren't literally taking bushels of rice to the market. [Answer] There are several problems with your premise. Money is something that has to circulate. If a society has a monetary economy, the circulation of commodities is intimately tied to the circulation of money; if circulation of money stops, the circulation of commodities also stops - and if it is a monetary economy, circulation of commodities must be the main, if not the only, way commodities are distributed. Problem is, if money has other utilities besides being a means of payment, people will always be tempted to use money as something else. In our case, people will be tempted to **eat** their money. And the only thing keeping them from that is the idea that the food that they might buy with their money is more (or much better) food than the money itself. But your description goes on to say that proper food is usually unavailable, so people eat money instead of it. Which means your money doesn't circulate properly; it is eaten, and therefore is withdrawn from circulation. In a low fantasy world, this would be extremely unstable; it would make the production of any other food inviable (who would pay for proper food? How do you prevent people involved in the production of other edible items from eating them, instead of selling it for... bad food?). All of this means that the economy will always be on the verge of returning to a "natural" (ie, non-monetary) economy, or, even more, that it will be basically a natural economy, with only a few markets where money actually circulates (and this would mean an economy that in all likeness is immature for an industrial revolution - there would be not enough demand for non-agricultural products to sustain an industrial sector, for people would have eaten their money before buying industrial gadgets). Of course, since your world is high fantasy, these things can always be explained away by magic; and if you start from the premise that the workings of your world are magic, it is probably better not to try and make all things explainable in terms of a non-magical world. You have to suspend your readers disbelief; if you try to explain too much, you risk raising their doubts instead of dispelling them. The money in your world is tablets of food. As long as you explain how they would be able to buy both a large house and a pair of shoes, that's it; if you try to explain how they would run a stock market, or even banks, based on food-money, you risk to put all your system under scrutiny, instead of keeping your readers focused in your story, which is what really matters. ]
[Question] [ A soft and vulnerable intelligent underwater species, you can consider them closely related to Earth's octopus - in the way chimps are closely related to humans. Consider that clothing is often worn for: * Status * Warmth * Modesty and, if possible, should last at least 3 months within sea-water without decomposing. What kind of clothes would work best for underwater? Or, if you don't think octopus society would use clothing for the above points, what would they do/use instead? [Answer] **They probably wouldn't wear clothing all the time.** Like Cyrus and some others I suspect that an octopus-like species who are so much more flexible than humans would find clothing restrictive. *Humans* often find clothing restrictive and we are far less stretchy than octopi. How would you shape a piece of clothing that would go on an octopus? Sleeves would be a lot of work to make for all eight arms and more importantly would obstruct the sucker pads on their tentacles. They *use* those pads. A garment that covered their head/body ("mantle"?) would obstruct their gills, or if it had a hole for the gills, would scarcely cover enough of their bodies to make a difference in terms of warmth. Reinforcing the point about flexibility is a related point about [buoyancy](http://study.com/academy/lesson/buoyancy-calculating-force-and-density-with-archimedes-principle.html). The density of octopus bodies is much closer to the density of the medium they live in, water, than the density of human bodies is to the density of the medium we live in, air. That's why the force of gravity *appears* to be less underwater and why sea creatures can just swim up the side of a cliff where we would have to laboriously and dangerously climb it. The relevance to clothing is that humans spend most of their waking time upright or semi-upright and gravity ensures that their clothing stays put, draping decorously downwards. Octopoids would live in a much more three-dimensional world, swimming up, down and all around. Clothing would float a lot more, tangling up with their tentacles and making locomotion and modesty difficult. It would need tighter fastening than human clothing just to stay on. **But let's say they do wear clothing sometimes. What would it be like?** Nonetheless, I can see that they might wear clothing on occasion, despite its inconveniences, for adornment, status, identification, protection or other reasons. We put up with uncomfortable clothes, why shouldn't they? Llario's answer has already suggested fish skin as a fabric. This is the best choice: it is available, it is flexible, and it is designed by evolution to last underwater. I do not know whether any sort of processing would be possible or desirable to make it last longer. Presumably you would have to very carefully scrape off all traces of flesh from the skin or run the risk of attracting predators. I can't imagine that [tanning](https://en.wikipedia.org/wiki/Tanning) is relevant underwater but I'm very ignorant in this area. Another option is fabric made from fibres, possibly derived from seaweed or other sea plants as also suggested by Llario. Woven fabric is the easiest form to invent. Weaving has a little "give" to it, but not much. It took centuries of development to develop the pattern shapes of a standard human jacket or pair of trousers that allow reasonable movement without using up vast amounts of fabric. These difficulties will be greater for octopoids as I said above. I don't think they'll use woven fabric for practical clothing, but they might enjoy swirling their woven cloaks in the water when making a dramatic entrance to a party. For clothing stretchy enough to allow flexible sleeves for their tentacles and figure-hugging coverings for their mantles into which gill-openings could be made, they need to learn to [knit](https://en.wikipedia.org/wiki/Knitting#History_and_culture) or crochet. They really could wear beanie hats. [Answer] Shark skin for the rich show-offs, less valuable fish skin for everyday jackets, seaweed fabrics for standard clothes. If you allow synthetic fabric then latex will be the first choice for working suits. Standard clothes will use paillettes a lot, 'cause underwater there is such a few light, matte clothes would be too anonymous... Warfare would see an evolution from fish bones to shell plates, crab full plates, heavy whale bones. The advancements in weapons will make such heavy armours obsolete and fighters will move to camouflage patterns on lighter textiles. And for some reason when I think about octopus people I cannot help but figure them wearing monocles... [Answer] Semi-sentient (level of dog or lower - it can even be fungus) species that form symbiosis with wearer. It's not dead, therefore has less chance of dissolution and it allows for breeding better clothing - also, chance for genetic engineerimg at some point. Even we have some clothes that eat sweat at this point, I think. If we had symbiotic relationship with any species, we'd have contests for purebred symbionts as we have with cats, dogs, etc. Symbiosis between species is nothing new in nature, as is breeding better useful species in civilized setting. There could even be clothing rights activist that want there to be no clothing cruelty. If that,s not your cup of tea, shells are pretty durable in some species. There could be a crab colony protecting yor mermen. Can you imagine an underwater knight in crab armour, whose armour attacks you with the fury of the woman scorned waving dozens of tiny claws covered in some sharpening solution? [Answer] Have you looked at what human divers wear? Really, any non-flush clothing would make absolutely no sense underwater. Why would a sea-based creature want to wear something that makes it move 3 times slower? And get easily entangled in things? (dangly clothing won't just sit down nicely as it does on land). And what's this talk about fish skin? dead biological matter gets dissolved in moving salt water in days... What are you even talking about? They would wear the same kinda stuff that divers/surfers wear - rubber, latex, neoprene... And it would be purchased from humans because it could not be produced underwater. [Answer] Aquatic species with gills has much less use for clothing than we do. They either survive direct contact with their environment or they die. So we can ignore protection from elements as a criteria. Protection from attacks is feasible, but you are probably not asking about my designs for octopi plate mail. So let us skip that too. So clothing would be used for status and decoration. The simplest solution for that is **paint**. Assuming your octopi does not have the color changing ability some octopi here have in which case they have no need for clothing ever. So the octopi would paint themselves with their status identifiers and add some personal decoration to it. Richer and more influential octopi would have larger patterns and use more expensive colors. The common rabble would have no paint at all and being able to afford and earn some status markings would be the common goal. Trade in pigments would be thriving and possibly justify long range commerce. Additionally small stones, sea shells, flowers and other small decorations could be attached as decoration. [Answer] **How octopi might use clothing** Octopi are an incredible order - and it just so happens that some species actually use something that could loosely be considered clothing. Coconut octopi have been observed carrying pairs of half-coconuts or shells around with them to wear as camouflage and defense - as seen in [this video](https://www.youtube.com/watch?v=BFda1MZ54G4). They pull the pieces together over themselves when they are lying in wait for prey or threatened. Now this is not really clothing as it is only put on when they come to rest, but you can see how the concept could be adapted into a sort of suit of armor. One of the benefits of being in the water is that it can support the weight of such armor, making it more practical than on land. It seems unlikely that octopi would use clothing for warmth, as insulation would be of little use since they are ectotherms, so don't generate much heat. Clothing to keep them warm or cool would need active heating or cooling systems inbuilt. I don't know about whether they would use clothing for status symbols or "decency", as your octopi analogues clearly differ a great deal from extant octopi in social behavior given that they have a whole society. Use of clothing as a status symbol seems plausible, given there are a range of similar behaviors in nature (such as bower bird nests). However a major use of clothing you have missed is for disguise. Octopi are masters of disguise, and the best of the best is the [mimic octopus](https://www.youtube.com/watch?v=t-LTWFnGmeg). Clothing could be used to take it's disguises to another level. **What would octopus clothing look like** I would suggest octopus clothing would likely take the form of a hard shell of some sort, which the octopus can draw it's whole body into when threatened or hiding. It might even have spines. It would also probably be modeled after something else - either a perfectly innocuous rock, or another species - so as to fool predator and prey alike. One of the key advantages of an octopus is it's ability to morph it's body into any shape, and I suspect they would be unwilling to give up this ability lightly. Therefore I expect there clothing might be quick release, allowing them to ditch it when they need to get through a small hole. **Below is a mock-up of a possible octopus garment** [![octopus enclosed in a rock-like shell adorned with an urchin](https://i.stack.imgur.com/Wm1jZ.png)](https://i.stack.imgur.com/Wm1jZ.png) This suit has the following features: 1. a hinge to allow rapid removal if the suit becomes an encumbrance 2. a hook for easy release using tentacles 3. a faux sea urchin (with real spines) for added protection 4. eye holes 5. tentacle holes **Materials used for this garment** This could be constructed primarily from a piece of hollowed out coral rock. The urchin spines could be collected from real urchins (which might also be eaten). The spines might need to be replaced quite frequently, as they are quite brittle. The hinge and hook could be made from plastic/rubber [which is found in abundance in our oceans, and lasts a long time](https://blogs.ei.columbia.edu/2011/01/26/our-oceans-a-plastic-soup/). Or perhaps from biological materials, such as kelp fibers, fish leather or fibers from [shark egg cases](https://en.wikipedia.org/wiki/Egg_case_(Chondrichthyes)) [Answer] **Grease.** [![ocean grease](https://i.stack.imgur.com/vFDxX.jpg)](https://i.stack.imgur.com/vFDxX.jpg) <https://oceangrease.com.au/pages/the-story> This would especially be true for a species which itself secreted a greasy coat. Grease reduces contact between water and skin, inhibiting unwanted cooling (or heating). Contaminants in the water touch grease, not integument, and are washed away. Parasites will be dissuaded by the grease film. The grease / water interface reduces friction. Also body paint can be decorative - I don't think distance swimmers go in much for this but certainly your aquatic species could. Distance swimmers grease their bodies, which has a number of benefits including some of those above. ]
[Question] [ The proximate cause of the [Anglican Church's split from the Roman Catholic Church](https://en.wikipedia.org/wiki/History_of_the_Church_of_England), which retained more vestiges of Roman Catholicism than other major early Protestant Church denominations, was the desire of the King of England to divorce his wife. One way that the Roman Catholic Church could have navigated this crisis could have been for the Pope to declare, [with ample Biblical precedents](https://en.wikipedia.org/wiki/Polygamy_in_Christianity), that it was doctrinally permitted for people of great wealth who could afford to support more than one wife without a doubt economically, to be married to more than one woman at the same time. Allowing this practice would also have discouraged the rather common practice of [British monarchs murdering or executing their spouses](https://www.historyextra.com/period/tudor/murder-conspiracy-and-execution-six-centuries-of-scandalous-royal-deaths/). Martin Luther, in Germany, as leader of the new Lutheran Church wrote [a little known epistle to a minor German aristocrat](http://whatdidluthersayaboutpolygamy.blogspot.com/) at around the same time which stated that Lutheran Christianity did not have any scriptural basis for a prohibition on polygyny, and that therefore it was allowed. If the Pope had followed the lead of Martin Luther and created a narrow exception to monogamy for very wealthy aristocrats, could Roman Catholicism have remained the religion of England, or was schism inevitable for other deeper causes of which the divorce question was merely a symptom? Why would this have been possible or not possible? [Answer] **Would sanctioned polygyny have stopped Henry VIII from forming the Anglican Church?** This is what you're really asking, isn't it? The answer might have been yes, but Henry's famous desire for an heir was by no means the beginning of the schism between English government and Rome. > > The conflict of authority in England between church and state certainly dates back to the arrival of Augustine, and has simmered for many centuries. The murder of Thomas a Becket was one of the more famous episodes of this conflict. The Magna Carta, signed by King John in 1215, contains 63 points; the very first point is a declaration that the English church is independent of its government. > > > The beginning of the sixteenth century showed significant discontent with the Roman church. Martin Luther's famous 95 Theses were nailed to the door of the church in Wittenburg in 1517, and news of this challenge had certainly reached England when, 20 years later, the Anglican branch of the church formally challenged the authority of Rome. Henry VIII dissolved the monasteries and abbeys in 1536. > > > **There is a public perception, especially in the United States, that Henry VIII created the Anglican church in anger over the Pope's refusal to grant his divorce, but the historical record indicates that Henry spent most of his reign challenging the authority of Rome,** and that the divorce issue was just one of a series of acts that collectively split the English church from the Roman church in much the same way that the Orthodox church had split off five hundred years before. ([source](http://anglican.org/church/ChurchHistory.html)) > > > So the honest answer is more likely, "no." Polygyny would simply have delayed the inevitable. **Even if polygyny stayed the formation of the Anglican church, it would have had some serious reprecusions** If I remember correctly, there were regular problems with non-inheriting sons in medieval Europe (not just England). This problem would have exploded the proverbial ten-fold had polygyny been legitimized. Indeed, it might have brought about the shift from feudal Europe to democratic Europe much more quickly. There are few things worse in the world than an entitled son who is entitled to nothing. ***I'm therefore compelled to answer "no." Polygyny would not have preserved the preeminence of Catholocism in England.*** [Answer] ## First things first I would like very much to read an alternate history book where, in an attempt to preserve England for the self-titled Universal Church, [Pope Clement VII](https://en.wikipedia.org/wiki/Pope_Clement_VII) steers an [Oecumenical Council](https://en.wikipedia.org/wiki/Catholic_ecumenical_councils) towards pronouncing that polygamy is permissible. I would *especially* love a book where the doctrinal and temporal machinations needed for such a radical pronouncement would be explored in detail. This being said, there are *massive* problems with the suggestion. ## Why is polygamy not allowed in Christendom? Seen from a great distance, Christianity is a particularly non-observant Jewish sect. The original founders of the Christian religion, notably [Paul](https://en.wikipedia.org/wiki/Paul_the_Apostle) and the anonymous author of the [*Luke-Acts*](https://en.wikipedia.org/wiki/Luke%E2%80%93Acts) duology, were undoubtedly Hellenized Jews, who were not aware that they were founding a new religion. Is it uncontestable that Christianism began as a movement to reform Judaism and open it to the world. Now, at the time when Christianism was emerging from the religious debris resulting from the fall of [Second Temple Judaism](https://en.wikipedia.org/wiki/Second_Temple_Judaism), the Jewish religion had no problem whatsoever with polygamy; it was the *Roman authorities* who had a big problem with polygamy and insisted on men having at most one wife at any given time. And let's not forget that the original founders of Christianism were *Hellenized* Jews, and the Hellenistic world had inherited from the Greeks a strong presumption that civilized men did not have more than one wife at any given time. Sure, they could have more than one wife, but only *serially*, not simultaneously. In short, when it all began the equation was simple: civilized men are married with at most one woman; being married with two or more women at the same time is for barbarians. Christianism was trying to take over the people of the Empire; and the people of the Empire were civilized; and civilized men did not take more than one wife at the same time. Not only they didn't: they couldn't. The law was very strict. It was *unconceivable* to preach a religion which did not emphasize monogamy. It would have been perceived not only as utterly alien, but as fundamentaly barbarian; and one thing the inhabitants of the Empire agreed on was that they were not barbarians. By the time of Henry VIII the Church had accumulated a millennium and a half of dedication to monogamy. Reversing its stance would have required a massive dose of radical thought, something for which Pope Clement was not known. And then there are the practicalities. ## The practicalities First of all, in the times of Henry VIII, the Popes did not have unquestioned [papal infallibility](https://en.wikipedia.org/wiki/Papal_infallibility); this doctrine was promulgated at the [First Vatican Council](https://en.wikipedia.org/wiki/First_Vatican_Council) in the second half of the 19th century. Sure, there were *some* medieval theologians who argued that Popes were infallible under certain conditions, but papal infallibility was not a black-and-white doctrine of the Church. Any Pope who would even contemplate the idea of allowing polygamy would have been *certain* that the Church would splinter and lose both people and territories to the Protestants and the Orthodox. The only non-insane way to declare polygamy permissible in the eyes of God would have been to summon an Oecumenical Council, and work to get a consensus. Second, we must dismiss out of hand the idea that the Church would even attempt to *"doctrinally permitted for people of great wealth [...] to be married to more than one woman at the same time"*. It is a basic doctrine that all men and women are equal in the face of God; stating that rich men are more equal than poor men would have been anathema in the 16th century as it would be today. This cannot possibly work. Either *all* men can marry more than one wife, or none can. Third, there is the problem that all men *and* women are equal in face of God. Having one rule for men and another for women would have been quite iffy; borderline possible, but practically guranteed to raise a lot of opposition at the Council. Fourth, such a decree would have placed canon law in stark opposition with the secular law of all Christian countries. For that millennium and half during which the Church had placed itself firmly on the side of monogamy had had the effect that the *secular* laws of all countries banned polygamy, had strict punishments for polygamous perverts, and did not even consider the possibility of people having more than one spouse. After all, king Henry was not concerned much with the sinfulness of having more than one sexual partner: what he wanted was a *legal heir*. Fifth, the Church would have had to innovate and emplace a new form of marriage ceremony. As inherited from the Romans, Christian marriage ceremonies emphasize the equality of the groom and the bride and require freely given consent. The new form would have had to insert one or more third parties, namely the pre-existing wives, and devise a form for all the parties involved to express their approval and to take the respective vows. (The pre-existing wives need must be part of the ceremony because they are to accept the new wife as a sister and take vows to live in peace; a vow is not valid unless freely taken.) Having the Catholic Church devise a radically new form of marriage ceremony is not a task for the faint-hearted. ## The tactical situation *Pontifex Maximus* is a great and ancient title, and it confers great power. Except when it doesn't. The tactical situation was that at the specific time in question Pope Clement was not a free man. In 1527, the soldiers of the [combined empires of Charles V](https://en.wikipedia.org/wiki/Charles_V,_Holy_Roman_Emperor) had [sacked Rome](https://en.wikipedia.org/wiki/Sack_of_Rome_(1527)); the Pope himself had [escaped disguised as a humble peddler](https://en.wikipedia.org/wiki/Pope_Clement_VII#Sack_of_Rome). When the petition of king Henry VIII for the annulment of his marriage with [Catherine of Aragon](https://en.wikipedia.org/wiki/Catherine_of_Aragon) reached the Pope, Clement was for all practical purpose a prisoner of the emperor. And Emperor Charles V was the nephew of Catherine. [![Emperor Charles V reigning resplendent over his vanquished foes](https://upload.wikimedia.org/wikipedia/commons/thumb/a/ac/Allegorie_du_regne_de_Charles_Quint_16th_century.jpg/640px-Allegorie_du_regne_de_Charles_Quint_16th_century.jpg)](https://commons.wikimedia.org/wiki/File:Allegorie_du_regne_de_Charles_Quint_16th_century.jpg) *Emperor Charles V reigning resplendent over his vanquished foes; pope Clement is second from the left, standing next to sultan Suleiman I of the Ottoman Empire. 16th century allegory. Reproduction available on Wikimedia, in the public domain.* Both the Most Catholic Emperor and the Catholic Church were also much preoccupied with the issues resulting from the [Protestant schism](https://en.wikipedia.org/wiki/Reformation) which was making inroads in the Germanies. By allowing polygamous marriages they would have given the Protestants direct proof that the Church of Rome was truly the [Whore of Babylon](https://en.wikipedia.org/wiki/Whore_of_Babylon#Reformation_view), possibly with the immediate consequence of pushing more German princes into the welcoming arms of the [Schmalkaldic League](https://en.wikipedia.org/wiki/Schmalkaldic_League). ## To sum it up * The Pope was not able by himself to make polygamy permissible. He would have needed the consent of an Oecumenical Council. * The Pope was under the thumb of Emperor Charles V, the nephew of the spurned wife Catherine of Aragon. * Both the Emperor and the Pope had much more pressing issues on their mind than the matrimonial situation of king Henry. * Even if they had considered it, it was not a simple thing to do. Lots and lots of changes would have to be effected both in canon law and in the rituals, entailing a massive risk of splintering the Church. * And even if the Church would have been willing, English law was not ready for it. [Answer] There's a fundamental flaw in this question: the assumption that the Anglican Church was Protestant. It was not. It was the Catholic Church with Henry VIII in charge rather than the Pope. Protestant churches were based on more basic doctrinal differences, e.g. Martin Luther's 95 Theses. See the related question on the History site: <https://history.stackexchange.com/questions/46240/how-did-the-general-population-of-england-convert-so-smoothly-to-protestantism?s=8%7C35.1949> [Answer] It did survive. There are Catholics in the UK. The protestant/catholic fighting was regional and cultural as much as it was religious. Polygamous societies cannot compete with monogamous ones. Poly societies under-utilize their male workforce, since so many of them fight/exploit each other for a chance to reproduce. They always end up with a horde of angry, virgin men, and you can't always dump them onto the EU, if you know what I mean. There were a great many criticisms of Catholicism. At its core, the mysticism - conducting religion in a language that your flock cannot understand, was the big complaint. The Church of England is *very* similar to Catholicism in terms of ideas. They broke away so that they could stop taking orders from the Vatican, and so that they could study the bible in their native tongue. If the European aristocracy had gone poly, it would have hastened the revolutions that killed off so many of them, and no way would it have delayed the enlightenment. ]
[Question] [ In the [MARS](http://channel.nationalgeographic.com/mars/episodes/power/) series of *National Geographic*, an organisation is steadily colonizing Mars by sending a handful of people every few months. However, these aren't ordinary people, of course; they are top-notch scientists of all kinds that have a mission to build up a civilization on Mars. However, I wondered, if we steadily send the best people we have from Earth to Mars to develop a colony, will we slowly create a smarter civilisation on Mars relative to Earth? What would the consequences be of this 'intelligence gap'? [Answer] Note: This answer assumes that those going to Mars have a high IQ (which I believe the OP intended), and that IQ is indeed a fairly good measure of intelligence. --- # Yes. I think the question of the most important factor, though, boils down to [nature versus nurture](https://en.wikipedia.org/wiki/Nature_versus_nurture): Will these individuals be smarter because of genetics, or because they're in an environment encouraging learning? # Points in favor of intelligence through nature: * [IQ heritability](https://en.wikipedia.org/wiki/Heritability_of_IQ) - the amount attributable to genetics - can be 0.45 in children in 0.75 and in older humans. That's reasonably high, and will be important in this population (see e.g. [Bouchard (2013)](https://www.cambridge.org/core/journals/twin-research-and-human-genetics/article/div-classtitlethe-wilson-effect-the-increase-in-heritability-of-iq-with-agediv/FF406CC4CF286D78AF72C9E7EF9B5E3F). * IQ heritability increase roughly linearly as a person gets older, until roughly 20 years (see [the Wilson effect](https://www.ncbi.nlm.nih.gov/pubmed/23919982)). In other words, genetics gets more important later on, when people are starting to take on jobs (and possibly procreating, in future years). * There will be a relatively small population at first, leading to a sort of inbreeding. This should concentrate the genes, given that the average IQ will be higher. # Points in favor of intelligence through nurture: * IQ is not always the best measure of intelligence. I don't want to get into that debate, though. * Children in each generation will likely have access to a good education. They will be raised by parents who expect them to learn to be scientists, engineers, and members of other STEM fields, as well as colonial leaders. As far as I'm aware, though, intelligence is passed mainly through genes. However, it's one thing to have potential, and another to be able to develop it. The environment will play another important role, and the combination should make for a smarter population. --- # The consequences This is another matter entirely. I don't know how quickly a change like this can propagate through the population. I assume that the first generation of colonists won't be too worried with procreating in the beginning, just staying alive. However, once things are suitable and safe, they can consider raising children. The delay, though, is not insignificant. Another important factor is what's happening on Earth. If all of the "smart" people are leaving for Mars, will that somehow reduce the mean IQ on Earth? I'm not sure; you'd have to send an awful lot of high-intelligence people away for there to be major changes through the planet. If this is the case, you might see some resentment towards remaining intellectuals. There will be something of a class divide: Those who are allowed to go out and explore and those who are forced to stay on Earth. People will not be happy if it's implied that they are "too dumb" to go to Mars. I recall reading *Brave New World*. At one point, it is revealed that > > There was once a colony only of Alphas - the smartest, fittest humans - that was a complete flop. > > > Nobody wanted to do the dirty work, so to speak. Everyone theoretically had good leadership traits, and they could do high-level jobs, but they couldn't do grunt labor. Consider this when thinking about your story. [Answer] Depends on: * the **level of automation** the colony is capable of (do you need sewage-recycling and potato peeling crews, or is it all done by cunningly crafted machines with properly implemented AI). If more mundane functions are required, it's likely that lower-skilled (and indirectly, lower IQ) folks would be required to conduct them, or the colony would not be viable. * whether the population would both be full-time colonists and actually produce a sufficiently large number of children to maintain a viable population -- a Mars posting might be considered **a temporary hardship posting** -- kinda like working on an oil rig or at a Polar research center -not a lot of kids born in Antarctica. * whether **eugenic policies** are enacted -- i.e steps taken (or not) to control for the effect of mean-reversion -- the tendency for children of high-IQ parents IQs to revert towards the population mean. This requires some explanation. Think of (the heritable component of) IQ as a result of the interaction of a few thousand genes (or un-methylated genes manifested in protein cascade complexes) mostly recessive, or dependent on many parts that effectively act as if recessive if any step is missing. If the parents don't have enough pieces in common to maintain the cascades (F depends on E, E depends on D and C, D depends on B, C depends on A), the child loses IQ points. Mean reversion is a statistical truth, not a universal one: very rarely, very smart (160 IQ) parents will have even smarter children (new or highly effective IQ-boosting gene cascades activated) but that's a far-off tail-end distribution (maybe 1 in 50 children of very high IQ parents will exceed their parents). This can be in part alleviated by, from most to least effective 1. Scientifically selecting germ cells and ensuring desired characteristics are in. (Keep in mind that identifying IQ boosting traits is hard and moreover some IQ boosting traits might have deleterious effects on phenotype functionality say via a predisposition towards neuroticism, so a high level understanding of the complexities of gene expression is required, currently outside our reach) 2. Breeding in a small pool (i.e. Parsis or Ashkenazi Jews where many of the cascade components are ~100% prevalence); or 3. Ensuring that the high-IQ parents also have high-IQ siblings, parents and grandparents. Given the politically left-leaning proclivities of most scientists and the bad reputation eugenics got in the 20th century, unless a colony is founded specifically on these principles and self-selects for individuals with these values, such an outcome is unlikely. * the capability to optimize the environment and control **toxin levels** -- there are many substances on Mars such as perchlorates that are plainly toxic to humans, this one in particular by confusing signals from/to the thyroid gland. The silicates form a fine powder that will electrostatically stick to all EVA suits that can combine with water vapor to effectively form a type of cement in one's lungs. Moreover, without a radiation cover, the habitats would have to be underground or otherwise well-shielded to prevent harmful cosmic rays from affecting cell functioning. * the capability to provide **effective education** -- a non-trivial challenge in the context of a resource-limited colony without the full technological might of a >$100 trillion 2016 USD world economy to back them up. * the unknown variable of whether human embryos/children have the capability to **develop optimally** within Mars' **reduced gravitational field**. As Earth-evolved mammals, there are many evolutionary shortcuts that may take a 1g gravitational field for granted, and could result in severe impairment. To date, we have a sample size of 0 humans raised in less than 1g. [Answer] # No Intelligence is hereditary to a certain extent. However, here are some things to consider. * Is life on a frontier colony where a lot of effort needs to be expended to survive the best for passing on the math, science, and medical knowledge that the parents have? * Is the set of people who are excellent at research and problem solving, the same as the set of people who are good parents? Is there even significant overlap? * Are the 'best people' more genetically pre-disposed to intelligence or to hard work? * Are the 'best people' the best because they have the best genetic material, or because they were born into the upper-class of the wealthiest countries? Remember, the reason there are a lot more physicists in the Germany than Ethiopia isn't because Germans are necessarily smarter. You can answer those question as you will, since they can be a bit touchy, but my conclusion is that the genetic intelligence gap between the 'best people' sent to Mars and the plebians left on earth will not be significant. [Answer] ### Not Necessarily There's a strong chance that this would indeed be the case in the short term, but not necessarily in the long term. ### Intelligence Studies all point to intelligence being a genetic factor. In other words, our potential has some built in limits. The people being sent to Mars are probably above average in many ways. However, not all those ways are necessarily genetic. You see, your genetic potential also needs an opportunity to be reached. You need a society which opens the doors to you getting a good education, and discovering those area you shine in. Some people are great athletes, as well as intelligent, but only pursue a career in sports. Others have a potential to be quite strong, but enter academia, and never develop a habit of working out. There's many possible combinations. ### Compromises The bunch being sent to Mars are interesting because they no doubt meet quite high intelligence standards, but they must also meet certain physical standards as well. And so, a very important question is just what balance was struck between intelligence and physical fitness. Some compromises might have been in made in order to mitigate a lack of fitness in very intelligent individuals, or a relatively lower intelligence in the strong individuals who have certain key skills the future colony will need. ### Potential Once the colony is established and the first colonists land, they will soon discover that their lives will now be a lot more difficult than they were back on Earth. Children born there will (arguably) have access to fewer resources than our children will. Will they really be smarter? They may have a genetic predisposition to be more intelligent than your average Earthling. However, they will also live in a much more dangerous and stressful environment, where they might have a lot less opportunity to innovate, and generally reach their full potential compared to a child of similar intelligence here on Earth. This is because their existence will be a lot more focused on survival than on simply developing their own potential. ### Future Colonists Also important to keep in mind is that eventually it will become economically viable, or even necessary to build up the Martian colony. By far the fastest way to do that is to send specialists from Earth over there to help them expand (rather than wait for several generations to grow up). And so, when this new workforce is sent over there (some of them perhaps only temporarily), will the intelligence standards for them be quite as stringent as the ones for the initial colonists? Will all the future settlers and colonists? Most likely not, as there will be a pressure to colonize, and if everyone is super intelligent, then who will want to perform the menial labor type of jobs? Not the professor level educated engineer. ### Conclusion In the short term the colonies will be populated with very intelligent individuals, however over time this gap will most likely narrow significantly. [Answer] Intelligence does not equal wisdom. Just because someone knows a lot about physics doesn't mean he/she knows a lot about other aspects of life. They're experts in their fields, sure, but not superhuman. Further, you won't build up a civilization if you only send your top scientists to a remote colony. The population is a key component in creating a civilization, and you will need people performing other basic activities. While it sounds nice that by sending the best people there, you're sending your best to create a new world for humans to inhabit, in order for them to not entirely depending on export from earth, they'll eventually need people who are doing things like making bread, cleaning streets, teaching kindergartners, etc. Hardly things that top scientific minds would excel at. Over the years, we appeared to be smarter not because we keep breeding the smartest people we have. While that might be partially the cause, the main pusher is the improvement and availability of education to the masses. The peasants of middle ages appear to be dumb compared to today's children because the people back then didn't have readily available schools and universities for all children. There is a thing called *Flynn effect*, you can look up the details on how various aspects affect an apparent steady rise in IQ in our children across the world. So, what's most likely going to happen is that once a society is built up and we're pushing it to make it self-sustaining, we will need to send more people who cover the spectrum of intelligence to the new colony. The intelligence gap will possibly be there, but it'd be similar than intelligence gap between the United States and, let's say, England. There will be a lot of prestigious schools on both sides, but with possibly different focus. And overall, the intelligence gap will not be too great to the point that they'll look down on us and call us filthy earthlings. We simply cannot only send our top intelligence to a remote planet and hope they'll build a society of smart humans. [Answer] There are tons of studies on this question, but imo -- if a woman is well fed, the man providing the sperm was healthy, she is , happy (stress kept to a minimum) and healthy and her child is born without a defect or medical issue, and if the child is nurtured, fed and educated to the best possible level -- they have a better chance to use whatever IQ they came with. I think IQ is inherent to a degree, but that environment makes a tremendous difference. My own IQ is high, but I was not taught maths or sciences, so what difference does having a high number make? Not much. [Answer] Studies, at least decent studies, do not show that intelligence is inherited. They show a significant correlation between measured IQ's in identical twins. This does not, in itself, show that inheritance is a big part of the overall mix. It is fairly clear now that brain development depends on both a large number of genes, and the development of the brain in the womb. The best summary is that you cannot meaningfully separate genetic effects and environmental effects, and it is a conceptual nonsense to try. There is a big literature on this topic. See for example :- 1. Dickens WT, Flynn JR. Heritability estimates versus large environmental effects: The IQ paradox resolved. Psychological Review. 2001;108(2):346–69. 2. Zuk O, Hechter E, Sunyaev SR, Lander ES. The mystery of missing heritability: Genetic interactions create phantom heritability. Proceedings of the National Academy of Sciences. 2012 Jan 24;109(4):1193–8. [Answer] Definitely YES, for two reasons: Firstly because all their genetic parents will be rather on the clever side, as was already noted in the other answers. Not clear if the effect will be large. Secondly because those kids will grow up in a world without war, hunger, and poverty, much less drugs, and well educated parents, good own education, and proper health care. All kids have a good chance to live up to their potentials. [Answer] No. The population of Mars will, at least initially, be selective. The skills and abilities will be selected for the Mars environment and, yes, we would expect highly educated people with a correspondingly high average IQ (but their range of skills and experience outside those specifically used for selection might be very limited). However, these skills will be specialized and the environment a restrictive one for the raising of children, with many types of experience simply unavailable to them and the natural world of Earth effectively alien. The narrowing of the range of learning experience in formative years will have a generally damaging effect on the full range of IQ, although some specific IQ abilities may score significantly higher relative to Earth. To put it another way, the 'best' people for Mars are not necessarily the 'best' people to produce the next generation. ]
[Question] [ [Cerberus](https://en.wikipedia.org/wiki/Cerberus) was a three headed dog, commonly depicted with a collar and tail of snakes. Such an organism is quite difficult to justify, but how can such a creature appear that way? Is there a realistic way that Cerberus could evolve? A list of all of the Anatomically Correct questions can be found here [Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798) [Answer] ## No, not without some really contrived circumstances To evolve three heads, Cerberus would need to evolve, for a long time, in a niche where it's better to have three sets of eyes, noses, teeth and brains than a single set of highly adapted eyes, nose and teeth. Let us note that evolution doesn't usually just sprout a new feature to achieve a given purpose, it starts with an existing anatomical feature then molds into the ideal shape for a given niche. Two extra heads with duplicated skulls of the first head is highly redundant. Practically everything you'd expect from three heads can be achieved more cheaply with a specialized single organ. Need to see in 360 degrees? Get chameleon eyes. Hear behind you? Articulated ears. Need to eat quickly? Get a giant mouth with lots of teeth. I can't think of a set of circumstances where it's a clear and long standing advantage to have three heads instead of just one. There are real costs to metabolism, neurological complexity and over-all competitiveness that come with three heads compared to a single head. Now, if you have a magic gene splicer and nursery, anything is possible...but that's not typical evolution either. [Answer] ## The side heads are actually hands Multi-headed animals are not very effective from an evolutionary standpoint, since there's not much you could do with three heads that you couldn't do much better with only one. But a quadruped with extra hands could be useful - four legs for stability, plus hands for manipulation and carrying things. To evolve this structure, you'd probably have to start off with a six-limbed body plan. On Earth this didn't happen with vertebrates, [but there's no real reason why it couldn't happen on an alien world](https://worldbuilding.stackexchange.com/questions/46839/what-evolutionary-benefits-does-a-hexapodal-body-plan-have/46857#46857). (This means that Cerebus could be in the same clade as centaurs, griffons, and dragons!) Over time, a centaur-dog could become more specialized for hunting and killing, and its hands could develop into powerful claws with pseudo-teeth that could tear prey apart from multiple directions like a pack of wolves sprouting from a single body. From there, the hands might evolve to look more like heads in order to confuse prey, who might fight back by attacking the false heads instead of the real one. [Answer] ## Polycephaly It's probably possible, but extremely unlikely, to find a Cerberus that would live more than a day. Many [advanced mammals experience polycephaly](https://en.wikipedia.org/wiki/Polycephaly#Non-human_mammals) but nearly all of them die within weeks of birth. Three equally-developed heads would also be a problem; one head would necessarily be in the middle, and the spine attached to it would probably be deformed from the pressure of the two surrounding spines, or deform the two surrounding spines with its dominance, which would result in three heads of differing mental capabilities. [![](https://i.stack.imgur.com/3knB2.jpg)](https://i.stack.imgur.com/3knB2.jpg) [Answer] **MULTIPLE HEADS** If let say a dog like the Rottweiler, Doberman, German Shepherd or maybe even a wolf was born with polycephaly and survives to mate and pass on its three-headed gene to its offspring then Cerberus is plausible. But what could likely have happened was that the acquiring of the third head was a gradual process. This could be supported by the fact that Cerberus was also depicted as a normal 1 headed dog, this let call it as Cerberus Senior. Cerberus Senior could have had the Polycephaly gene in it but as a dormant gene probably from some distant or recent ancestor. This gene however might have been activated in its offsprings or descendants, which could be supported by the fact that the three headed Cerberus was portreyed as the brother of the two headed dog Orthrus. If this gene was activated correctly in the two offsprings or descendants,Orthrus and Cerberus , that is if their brains each work in harmony with each other, then it is a successful recreation of Cerberus and Orthrus. **SNAKE TAIL** The snake tail could have been caused by a mutation in the tail hair of the Cerberus Senior or its predecessors that made the tail hair scale like, like the scales of a pangolin which is just mutated hair. This can be supported by the fact that both Cerberus and Orthrus are depicted as snake tailed. Therefore Cerberus and Orthrus are scientifically plausible but it is however highly unlikely that these mutations will be perfect and that Cerberus or Orthrus will survive till maturity. [Answer] It's a wolf with 3 heads. 3-headed animals are not unheard of, so it would be possible for a 3-headed wolf to exist. The snake tail could be a symbiote, trading protection of the rear in exchange for blood and poop as nourishment. I'm not so sure about the mane of vipers, but our Cerberus could have snake-like locks of hair that look so much like snakes that people would think that the mane was made up of real serpents. Therefor, Cerberus would be scientifically plausible. [Answer] ## Adaptive Conjoined Twins: My answer is actually going to be a variant of my answer to [THIS](https://worldbuilding.stackexchange.com/questions/187116/would-an-evolutionary-predecessor-for-winged-quadrupeds-start-with-four-legs-and/187138#187138) question based on some creative developmental handwavium. I would imagine a fantasy world where a developmental mutation occurs, is somehow taken up by a common virus, and spread to many new species. In this case, you need a stable genetic shift that causes essentially all fetuses to create conjoined twins. Fortunately, we're talking ***domesticated*** animals, so the evolutionary pressures have a lot more to do with what humans like, rather than what is adaptive. You start with a dog that consistently creates conjoined twins that re-merge due to developmental genetic variants. Maybe this is because the dog is a fun chimaera with two heads and neat growth patterns. Maybe they think guard dogs with extra heads are terrifying (this is especially true if there are superstitions about multi-head dogs). Who knows? All the variants that are non-viable die, and the ones that are merely dysfunctional are kept as really cool pets. But they ***could*** be at least partly functional, as humans with two heads and conjoined twin syndrome are sometimes reasonably functioning. So for argument, one head is consistently functioning, the other not so much. The more functionality, the more people love them and select for them. Now that you are selecting for crazy heads, A second mutation occurs. The non-functioning twin is getting different developmental signals (which is why it's the non-functioning one) and this one starts consistently growing two heads in a polycephalic manner. Now the resulting conjoined twin suddenly has THREE heads. This creates a huge stir among the breeders, who select for this like crazy. It LOOKS like a Cerberus, which may have been the original reason for the two-head breeding craze. You could end right there, if you wanted. But with a selective pressure to have more function, eventually the two "minor" heads become able to move and articulate. Now your three-headed guard dog might actually have some real usefulness, and the lesser versions are phased out. Because this is all developmental, you'll probably still get a natural failure rate where variants regularly occur. As long as people like the three-headed dog, they will keep selecting for increasingly stable versions. Any other Cerberus-like characteristics would be largely cosmetic and easy to select for. [Answer] In the Ringworld books, the "[Puppeteer](https://en.wikipedia.org/wiki/Pierson%27s_Puppeteers)" aliens have their brains located in their torsos, while their heads are more like a hand/eyestalk combination equipped with a mouth. An apex predator with a similar body plan could look very much like Cerberus or the Hydra. As for the "mane/tail of snakes", how about jellyfish-style stinging tendrils? If they were muscular hydrostats, like tentacles, they could be used to actively attack prey or defend the creature. ]
[Question] [ For the purposes of this question only, I am making the following definitions: * Cell: a microscopic, membrane-bound subunit of a living organism. * Living organism: an entity composed primarily of biological macromolecules that eats, reproduces, and evolves. Everything on Earth that is ***unambiguously*** alive today is composed of cells, from unicellular microbes to large creatures with hundreds of trillions of cells. I am curious about the possibility of non-cellular life. Could life exist without cells? * Specifically, could living organisms naturally arise from non-living molecules, evolve and increase in complexity, and go on to form a biosphere without cells arising at any point? * If such life is possible, how would it differ from cellular life? [Answer] Let me start with an obligatory reference to one of the great worldbuilders of Science Fiction: Hal Clement. In [Needle](https://en.wikipedia.org/wiki/Needle_%28novel%29) the alien visitor was a hard-SF take on the classic “blob”. It was explained that rather than being descendant from life using cells, it came from viruses, or something like that. Note that researches work with “cell-free” cultures, which is basically the gunk from inside a large number of cells but without walls cutting it up into little compartments. (Unfortunately Google doesn’t turn up any popular articles explaining that; only scientific papers *using* them and products aimed at keeping them.) Some “compartments"” in nature are not microscopic. Look at algae in particular. > > [![algae](https://i.stack.imgur.com/Xh5Cd.jpg)](https://i.stack.imgur.com/Xh5Cd.jpg) > > > Valonia ventricosa, a species of algae with a diameter that ranges typically from 1 to 4 centimetres (0.39 to 1.57 in) is among the largest unicellular species > > > However, you asked about *complex*. [Eukaryote cells](https://en.wikipedia.org/wiki/Eukaryote) can have features like cilla and internal organelles by diving up the cell with more internal membranes. A cell that’s large in one dimension, like a muscle cell or nerve, can have multiple nuclei. So what’s the difference between a large cell and a bunch of cells? Perhaps the distinction is less clear if the contents can move between them more easily and partitions can come and go. But it will still be *like* multi-cells because it couldn't have a single nucleus controlling everything. It would still have a high degree of unit-ness even if boundaries are fluid. [nigel222](https://worldbuilding.stackexchange.com/users/13883/nigel222) points out that a [plasmodial slime mold](https://en.wikipedia.org/wiki/Plasmodium_%28life_cycle%29) is exactly this: a single membrane without walls. This supercell is known biologically as a [synctium](https://en.wikipedia.org/wiki/Syncytium) or [Coenocyte](https://en.wikipedia.org/wiki/Coenocyte) (depending on how it formed) and is essentially a bag of cytoplasm containing thousands of nuclei. Follow the links to those terms for more about your subject of interest here. [![slime mold](https://i.stack.imgur.com/O3XQF.jpg)](https://i.stack.imgur.com/O3XQF.jpg) You might look at The SETI weekly Colloquium on [Power laws, predictable evolution, and the limits of life](http://www.seti.org/weeky-lecture/power-laws-predictable-evolution-and-limits-life). On one slide he shows that “things change” when limits are reached, and a higher level of organization is needed to make progress. This includes the boundary between simple bag-like cells and those with complex internal organization, and again with the largest of those and multi-cellular life. So limits will need to be overcome at a particular size. Could nature find a different way? Multi-cellular life was an easy solution since cells divide anyway: just stick around and cooperate to greater degrees. But understanding what the issues are with growing and maintaining itself with respect to energy and resources, you might find an idea to inspire a different solution that can be plausible in a good SF story. Without cells arising at any point, you ask? I don't think so. What would keep all the *stuff* together, and how’s that not a cell? Maintaining a compartment to keep all the stuff together is thought to be an essential starting point for true life arising from protolife, but that could just be our limited imagination. What do you even mean by not having cells at all? [Answer] What if the basic building block of an alien form of life developed on the *outside* of its basic structure instead of the *inside*? Cells use membranes to contain all the 'stuff' floating around inside them, but proteins can 'stick' to the outside of two-dimensional surfaces and in some circumstances move along those surfaces. This might actually be just as efficient a means of initiating life; less freedom to move around, but because they are locked to a 2-d surface they have a greater probability of proteins colliding, interacting, and forming new exotic structures. You might end up with a world where life's basic components are 'inside-out' compared to cells, shaped like protein strings or webs instead of enclosed blobs. All proteins would move along these strings instead of floating around in a liquid medium. Life on such a world would probably look and behave very, very differently. All life on Earth operates according to the basic assumption of forming a barrier against the outside world. Life on this alien world might be more prone to forming connections with other organisms instead of keeping them out and might eventually evolve into a single planet-spanning organism. [Answer] It may depend on the meaning of "macroscopic". Since the characteristics of microscopic organisms largely depend on pressure and mechanical resistance of the cell membrane, it is possible to find very large organisms with unicellular characteristics if you find the proper pressure or the proper material for a cell membrane (see the algae in JDlugosz answer). If you leave large unicellular organisms evolving for a long time, they may develop a certain level of complexity by developing organelles or other structures inside the cell. That may do what you want/need. In fact, taking a gas giant (a high-pressure environment where, at the right altitude, some gases are thought to be near-solid), you may find the perfect place for complex unicellular life to evolve. If such complex unicellular life is taken from its environment and manages to survive (say, being transported by an alien species from its gas giant and into a high-pressure rocky planet), they may even develop sentience by contact with a more manageable environment (not only made of near-solid gas). I hope that helps. ;) [Answer] Taking the suggestion of organelles/structures developing on the outside of a "mebrane" as mentioned above in a slightly different direction, what about a lifeform where nuclei attach and move along fibres or similar internal structures, and perhaps these structures could later evolve to take on functions of a kind of skeleton or even a muscle? Imagine a lifeform like the slimemold above, where it contains a number of fibres, and as it approaches some kind of obstacle, enemy or food source, it can "transport" nuclei or even mitochondria-like organelles into the direction of that "encounter" in order to process, (chemically) fight, or digest whatever it is meeting. Once that is done, the organelles or neuclei (or indeed whatever structure is hypothetically possible) can be moved to other places, or just be spread about evenly according to osmosis-like regulation. The issue with such internal fibres or structures of course, is that they would restrict the organism's plasticity, so they might have to take on a fixed form. You could either work with that, making them growing like a tree would, with fixed branches, etc., or you could argue that even these skeleton-like fibres can be spliced and/or reassembled again according to need. The entire organism would be encased in a membrane or wall depending on its evolutionary niche. Obviously, all of this might be incredibly improbable, but it seems at the very least plausible to me. [Answer] Maybe. You can imagine a planet that started with an alikaline, rather than acidic environment, specifically alikaline by the mineral kind, not the ammonia kind. Amines and imines are not very stable when treated with a base, and certain that quaternary amines, or the choline that makes up earth like cell membranes will not be able to be synthesized, let alone to form naturally within such environments. What you get then is a planet that was stuck in a RNA world, which that sugars are more available than fats or hydrocarbons. Whatever life you get will be assembled RNA or proteins that forms rigid, atomically perfect structures that resembles more like viruses than cells, crystals instead of flesh. DNA origami is a useful approach for nanotechnology today, and I certainly don’t see that if living organisms can not be designed out of it. Protein binds nuclei acids, therefore you get all the different effector tools, ribosomes are made of rna that binds protein or dna readily. Build a scaffold of intertwined RNA or proteins(RNA resembles DNA a lot) that forms repeating, or crystalline structures, then you get a nanofactory. That can potentially make copies of itself. DNA can make DNA, RNA can make RNA and RNA can make proteins, therefore the minimal requirement for life is really just to keep the central dogma going. We then throw in some form of nanoassembling, which is very common in all living organisms(flagellar motor in microbes, or nuclear pore assembly), then we just get a multi-particular viral "organism" that work just as well as the cells on earth, is not better. After all, all known function of cell membrane transport are based on proteins, with the few exception that is the diffusion of a few gasses, or unwanted toxins. Therefore, we can’t rule out a substitution made with proteins that specialize(on such jobs). Evolution of such life, if it is evolved at all, would likely happen within geodes or fissures, where concentration difference drives the crystallization process, forming the first crystalline "particles" which would become the building block of all other, higher form of life. Interestingly, such RNA based lifeforms have a much higher chance of evolving larger individually, rather than forming an analog or what we called "multicellular organisms". Clockwork based high order computations, or "minds" are more likely to be present as opposed to the electrochemical processes that makes up animal brains. (you can avoid pesky errors when your manufacturing is atomically perfect, therefore having no place for an error at all). Expect to see a lot of "tick tok" creatures around on such planets. Also, ribozymes are not prized for it’s ability to make energy, so expect to see thermodynamics as a prevailing work around, complete with all naturally evolved steam engines(as a replacement for photosynthesis) and a lot of giant analogs of enzymes or other biomolecules. (Anyone want a mechanical dinosaur that runs on steam, or a fully living, sentient robot made of plastic?) you can make this a steampunk/clockpunk or macromolecular world or location for your potential protagonists, even complete with things like a molecular sword or purely mechanical mounts to be discovered. [Answer] It all depends on degree of complexity required in your unicellular life-form. As already pointed out we already have "huge" (several centimeters or more) unicellular living forms. In our line of evolution cell membrane is an essential component of any complex organism because it specializes in several essential functions (e.g.: signal transmission, pinocytosis, active transport, etc.) which are difficult to imagine in a single cell. As dimensions and complexity grows need arises for specialized means to transport "materials" across the organism and to process it. In our evolution line this is accomplished specializing cells to form blood vessels, intestine, lungs, kidneys, etc. in an unicellular body all these functions would have to be performed somehow by internal organelles, which may be possible, but surely not easy or likely. It would also be debatable if this "megacell" divided in thousand of sections, each devoted to a function, can really be considered a single cell. In general a single cell is so because it has a single copy of the genetic code (syncytia are not considered a single cell, but multiple cells without separating membrane as they have multiple nuclei); it is not easy to understand how a single copy could suffice when dimensions and complexity grows. ]
[Question] [ In the desert, the major factors of survival are water, food and temperature. I have a city in a desert where the first two are covered by a nearby river and agriculture from that river, but would it make sense to build a city underground to beat the heat? Or would it be better to adapt the species living in the city to higher temperatures? [Answer] # Yes, underground would help with heat Given food and water are covered, underground living will be cooler$^1$ and safer than living in direct sunlight, but there are some caveats: ## Geothermal gradient As you descend into the crust, the temperature increases in a steady, predictable fashion known as the [geothermal gradient](https://en.wikipedia.org/wiki/Geothermal_gradient), which is about $25^{\circ}\text{C}/\text{km}$. Thus, your best bet is staying just a few meters below the surface. That way you'll get almost all of the insulating effects of the ground, while avoiding the increasing temperatures from below. ## Digging is hard Digging an underground city would be prohibitively difficult. Your people would be much better off to find an existing system of caves. ## Ventilation and heat regulation People generate a lot of heat and $\text{CO}\_{2}$ that need to be exchanged for fresh, cool air. Putting multiple entry/exit points to your city will help, but you'll still need air flow, and this will certainly take a lot of effort! You didn't specify the level of technology your people are at. Fortunately I can present a fan that requires practically no technology at all: Put quite simply, you take a large piece of lightweight fabric, animal skin, whatever, and affix it to a wooden frame about $16 \times 16\text{"}$ ($40 \times 40 \text{cm}$). Make several of these. Then you have volunteers/workers/slaves at the (preferably ramped) entrances constantly push the air out. You will need one such fan for every 10–100 inhabitants depending on how densely packed the city is. ### Inspiration: *Nuclear War Survival Skills* book My inspiration came from the public domain book [*Nuclear War Survival Skills*](https://en.wikipedia.org/wiki/Nuclear_War_Survival_Skills). Here is their diagram of the fan I described: [![Simple box fan](https://i.stack.imgur.com/eWjnWm.jpg)](https://i.stack.imgur.com/eWjnWm.jpg) At around p.59, they state that this fan can move 300 cubic feet/min, which is enough for 9 very crowded adults in hot weather, or up to 100 in cool weather. That book describes some other fans and is in general a great read for designing underground living on a small scale. --- With more technology, you can automate any type of fan somewhat by putting the fans on circular wheels or belts, and use some pulleys and gears to give the people (or beasts of burden) a mechanical advantage. Again, ventilation is necessary (and very easy to underestimate!). It will be hard work, but if done adequately, the underground would remain cool and hospitable to human life. # Water source You say you already have a nearby river. Does it run underground? Or is it at least somewhat near your underground city? If you can pipe some of it through your city, your inhabitants will have a much easier time with it, and the water will help cool the city even more. # Lighting You didn't ask about lighting, so I'll keep it short: mirrors. Placed around your ventilation/entrance shafts, you can "beam" sunlight into the city. Your people would want to keep fires to a minimum, as they generate lots of carbon monoxide, which can be easily fatal. --- 1. More moderate. Cooler during the daytime, and warmer during the night (a lot of deserts get quite cool during the night). [Answer] Your question is bit misleading. The important thing is not to be underground, the important thing is to have thermal mass of stone around you. A historical example of what you want is [Petra](https://en.wikipedia.org/wiki/Petra). Similar use goes up to stone age where people lived in caves that had stable temperatures year around. In addition to Petra other examples of [rock-cut architecture](https://en.wikipedia.org/wiki/Rock-cut_architecture) exist in Cappadocia and India where it was a result of suitable rock formations. In fact, I'd go so far as to say that such architecture will mainly exist in areas where you have natural caves or rock formations and easily workable stone so that the amount of work required is exceptionally low. Otherwise it will be easier to build above ground and just make the walls more massive. Typical solutions are adobe, mud brick, or [packed earth](https://en.wikipedia.org/wiki/Rammed_earth) which naturally allow relatively simple and easy construction of thick walls with high thermal mass. Actually building underground would generally be impractical since while the resulting architecture would indeed have relatively stable temperature the amount of work required would be higher than with other alternatives with same protection from heat. Additionally being actually underground would make it more difficult to deal with floods and sand. It is generally better to live so that gravity helps you keep your home safe from such issues. That said, it is reasonable for the desert city to have significant infrastructure underground. Underground aqueducts or [qanats](https://en.wikipedia.org/wiki/Qanat) or likely. Similarly underground tunnels make a good source of cool air for ventilation. This would be combined with a [windcatcher](https://en.wikipedia.org/wiki/Windcatcher) towers or similar. I guess you could say that the optimum is a combination of below and above ground elements. And that building above ground usually requires less labor and is the default barring natural caverns or exceptionally easily workable stone or special needs as with water conduits. [Answer] # Yes * Insulation against sun, wind, rain, and temperature changes! The [geothermal gradient](https://en.wikipedia.org/wiki/Geothermal_gradient) can help keep a cave system warm. Some houses use [geothermal heat pumps](https://en.wikipedia.org/wiki/HVAC#Geothermal_heat_pump) to warm or cool as needed, which can be extended to caves * Caves can often have natural choke points, allowing for easy defense. * Your city may be hard to spot. After all, it looks like any other bit of land! # The Other Issues * Light is an issue. Do you have skylights? Mirror systems? Do you use a lot of candles? * You need to dig out caves and rely on some structural engineering to keep things up. [People have had great success, otherwise!](https://en.wikipedia.org/wiki/Underground_city) * Fresh air needs to enter somehow. This requires ventilation, but that can be done. [Answer] The fact that underground cities in the desert in our own world are very few and far between, as far as I know, might indicate that it would either require some special knowledge or else a whole lot of work to create an underground city in one. I think adapting to the heat or finding another way to cope with it would be easier, and more likely, personally, but then, I like heat, and I like to study heat-tolerant life. Nevertheless, I'm sure you could find a way to make an underground city in the desert (even a practical way), but it sounds like it might not be the easiest thing to figure out. An underground city might start to smell after a while, too (however, probably less in a desert than a humid area, is my guess). If it was close to a river, it might get a lot of water from the river running into it (and I imagine it would smell a lot more; the dry banks of rivers that once were wet can smell pretty interesting). [You might consider what termites do.](http://www.greenbiz.com/blog/2009/09/02/how-termites-inspired-mick-pearces-green-buildings)\* They have natural air conditioning with the way their mounds are set up. This would be helpful to establish a constant temperature (deserts get cold at night). In the case of termites, they keep it at about 30° C all the time, where it fluctuates between about 0–40° C. outside. They establish a constant draft of air, and build so that the sun doesn't hit it as much at certain times. (\*Note in the link that it says termites have a brain the size of a pinhead, but I've heard that science has established that the size of the brain doesn't regulate intelligence necessarily, but rather ability to control a larger body.) You might also consider that the people of your desert might have materials that reflect infrared light (which could cool down whatever they're placed around a lot). Infrared isn't some special space aged thing. It's just a color you can't really see much, if at all (unless you've got super powers), because it's outside the visible spectrum for humans. (And, infrared light heats things up, much how UV rays give people sunburns, kill microbes, and stimulate vitamin D production. Plastic and modern glass usually block UV rays, and this helps to prevent damage of some kind or other—including to vitamins in milk and such, I believe. So, you would need a color that reflects infrared to keep things inside cooler.) In our modern world, you can get clear inserts to go on windows to block infrared (and stop the house from warming up through the windows). [You could do the same thing to your whole house (or city) with the right color of paint](http://www.eckart.net/markets/coatings/industrial-coatings/architectural-coatings/aqueous-systems/exterior/ir-reflecting-wall-paints.html) or something. [Answer] Survivability is probably not an issue, as others have stated - increased insulation from the heat, etc. The difficult part of this is creating a history for such a city. One doesn't simply pick a spot in the desert and decide to build a city there, there has to be a back story to explain how it got there. One possibility would be for it to have started as a normal, above-ground settlement that over time became increasingly buried under centuries of sandstorms. People started building covered walkways between the buildings to keep out the sand, and building tall chimney-like structures, both to allow for air circulation and also some with ladders to provide a means of egress from the buried buildings. These chimneys would continue to be built taller as the sand became deeper. Eventually, as modern technology became popular, they might also run electrical cables down some of the chimneys, as well as plumbing/sewage, and later telephone, ethernet, fiberoptic, etc. Some might even be converted into elevator shafts. Prior to being hooked up to electricity, their primary source of light would be torches, which produce smoke, and so these would also need to be placed near the chimney structures. It's possible you could line the edges of chimneys with polished metal to act as mirrors and bring some daylight down into the buildings, but again, this means most of the light would be near the chimneys. Some enterprising architects might see the benefit of designing arched ceilings so that any smoke from light sources would collect into the chimneys. One problem with this scenario is it does make it difficult to expand the city, as digging underground in sand is not a simple task. It's possible that additional structures would be built on the surface, which might themselves be buried by more sandstorms, so you have layer-upon-layer of city, with the deepest parts being the oldest and newer structures being closer to the surface. The most recent developments would be on the surface. Of course, any surface structures would have to be positioned such that they are not directly on top of the chimneys from the deeper chambers. Eventually, social strata would start to form based on depth. The above-ground level would be mostly traders and craftsmen, the type who would do business with outsiders most frequently. Below them would be the aristocracy, who being the wealthiest residents would choose the most comfortable lodgings - deep enough to be protected from the heat, but not so deep as to have little access to sunlight, fresh air, quick trips to the surface, etc. After that, things would go steadily downward in terms of social standing, with the poorest people relegated to living in the oldest, deepest parts of the city. [Answer] The best thing to do would be both. Snakes, lizards, and other creatures live in the ground during the day, when it's hot, then come out at night. You species could be nocturnal, resistant to heat, and be able to come out during the day if necessary. Being underground also helps insulate against all kinds of things. ]
[Question] [ I'm trying to work out a design for an isolated monastery populated entirely by sentient undead, and having trouble working out what would need to be there. If the entire population is vitally challenged, that means no need to eat or drink, and maybe sleep. So you wouldn't need a dining room, and you wouldn't need to devote space or time to food production. Some private space might be needed; alternatively, that might be seen as unnecessary in a heavily religious commune, especially if sleeping is unneeded. The centrepiece of the monastery would likely be the chapel/place of worship of some description, but what else would there be? What would they spend their time doing, with no need to farm subsistence? What would that mean for the layout? Assume a fairly standard pre-industrial fantasy setting as far as tech level goes. The head priest will be a mage, and a few of the others might also be. The place is totally isolated from other civilisation, no contact at all. Any thoughts? [Answer] I'm guessing that everything they do, they do to please their dragon overlords. So it will all come down to a few simple things: * Worship * Read * Clean/Repair * Train in combat * Ensuring the above tasks can continue to be performed indefinitely **Worship** Pretty self-explanatory. They would likely have a place to gather and worship together, to honor their venerable deities. They may also have private worship chambers, that would have thick stone so that they can worship and/or meditate in silence. I don't think there is much needed to ensure this task can keep going. So long as they are alive (sort of), they can worship. **Read** If you're undead and going to live forever, you need someway to occupy your time. They will likely read a lot of material about how and why their gods are divine, and then re-read it, and then keep on reading it until they can dictate every word of it from memory. And then read it some more. This means that they will need some sort of library to store their books, which will likely be the largest room in the monastery. Also the head priest/mage will need to stay quite mentally sharp, so they might have books about casting magic too. Books will eventually be worn out, so they will need to be copied onto new parchment/paper. This means they will need knowledge of how to make paper/parchment, as well as how to bind them into a book, as well as materials to write such as quills and ink. This supply may come from a small farm (containing whatever birds quills are made from, and goats to use their skin as parchment), or a garden with plants to make into ink (or however old ink was made) and trees to make paper. This means they will need to be proficient with gardening and shepherding etc. **Clean/Repair** This needs to be done, as if their dragon gods eventually visit them (that's the dream!) they will want the place to be presentable. And I'm guessing the dead produce a lot of dust, as they will consist entirely of dead cells. They will also need to make sure any of their tools for performing tasks (brooms, book binding equipment etc.) are repaired or replaced. This means they will need some sort of workshop to repair/make tools. This will likely be confined to its own area, such as an external shed or a side room that is cut off from elsewhere, as the noise and waste such as sawdust will pervade the common areas for worship and reading. All their common areas will also likely be quite bare, in order to make their cleaning easier, and I can't imagine they're materialistic or sentimental enough to keep things around for decoration, they would only own practical things like tools and shelves (and possibly chairs?). **Train In Combat** There's always the possibility that others might try to invade their monastery, so they will need to be able to fight them off. This means they will need to stay honed on their fighting skills, and also they will need weapons in good condition. Again, they might be visited by the dragons who will want them to march off to pillage at a moment's, so they will need to be prepared for that eventuality. This will require an armory, training grounds, and a smithy to make weapons. They will likely need to find the materials for weapons themselves, so perhaps also a mine of some sort to find iron. That is everything that I can possibly think of that they might need rooms for, or have inside their home. [Answer] They won't have to produce a lot of new items, just to repair or replace occasionally broken ones. But what they need, they have to craft from the scratch. * They'd better have some sort of mines and a smithy (making tools to repair the monastery, tools to protect themselves from wild animals, etc), and some communication line with the mines (maybe even a small settlement near the mines). * They need some wood for the tools, so there's some communication line with a nearby forest. Zombies also need wood in order not to freeze solid in the winter, so they might even have a lumber camp. * If they wear clothes (maybe ceremonial?), they have to farm cotton or linen, spin, weave and so on. So, there still are small fields around the monastery, and they need some rooms with clothes-making equipment. * If they are copying/writing books, they need to produce paper an ink by themselves. Again, some rooms with the equipment, and maybe a bigger cotton field. [Answer] If the undead population of your monastery feels a need to worship, that will probably be the one thing the majority is doing, 24/7 on their "knees" in the chapel. With only a few of them taking time off to manage the place. Standing guard is probably the second need, if there are nonsentient undead (skeletons/zombies) present, those will likely do this 24/7, not moving for weeks or years. Finally, the mage and his apprentices if any may devote time to study and occasionally have to prepare or gather resources for spells. If the monastery has been built to purpose by the undead, the chapel will dominate, the magical study will be close by (can be any size, depending on the requirements of magical studies) and finally there will be a general purpose storage/tool hall where all supplies are stored and repairs can be done. This also doubles as a place where any undead not engaged in worship can stay. [Answer] * They are members of the group who ruled over men with the help of the dragons. * They were overthrown, the dragons were killed, and the dragon leader disappeared * They believe the dragon leader will return and resurrect the faithful, so they encase dragon remains in tombs * They go into hiding --- The above bullets are points that already exist within the Elder Scrolls world. So, as a group who believes you will one day return to power with dragons that re-emerge, how do you prepare? * You stay faithful - continue worship of the dragons (*makes sense for a monastary as well*) * You remain ready to overthrow (*convince? see comment*) the men currently in charge. Given that the dragons granted power in the "voice" and the dragons are now gone, they can possibly continue to practice as the "Grey Beards" do. But perhaps they also remain prepared by continuing training in combat or magicka. 2. a secondary part of this bullet is that, if they are continually training, accidents *do* still happen from time-to-time which may mean that they need ways to "fix" their wounds. Given that they are undead, the wounds will not heal themselves with time. Other things they may do largely depends on the nature of the people who are there or their beliefs on what will be required to put the dragons back in charge. (*Factions could emerge - those who remain "truly loyal" vs. the ones who "are loyal but slack off in certain areas", or differences between thoughts on how they should prepare may also create different factions*) If they believe that entire armies will need to be outfitted, they may be continually producing weapons and armor in preparation. If they have remain secluded all this time because they are just fearful followers, they may have done nothing more than worshiped the entire time while believing the dragons themselves will fix everything and put them in charge for remaining loyal. [Answer] Good Day, Thinking about this, you could look up what real monks did in their... freetime (when they did not ora, but labora) When your civilization doesn't know the... uh, whats the name... letter press (?), than your monks could copy books the old way. Seriously, thats a task that takes real long time if you want your books to look pretty. In Germany something that does like a prime task for (male) monks seems to be brewing beer. There are dozens or monastery - breweries that still sell beer, and this isn't just a phenomena from Germany... all that once was holy roman empire or a hold of the knights from the german order (black cross at white ground) seems to embrace the idea of delegating the beer-production to some kind of monasteries. At least in the past. They could take care of childs... well... uhm... how does an undead population make kids? Take them from other civilizations graveyards? Anyway, schooling siblings might something they could do. Some monks actually did pretty well when researching stuff. At all, they did have the time for studies other might find to time-consuming. Mostly they discovered stuff that was themed around healing others. What plant does cure what disease. But whats a disease for an undead? Coming back to life? Well, to cure this not much research is necessary after all... And taking a look to the far east, you could have your undead lerning how to maximize the power of their bodies. They wont feel any pain maybe, so its time to develop Bone-Fu, which is performed by using your other monks loose limbs and... ehm... no. Its better I do not plot more about this topic... I wonder if someone did answer the same stuff while I was typing this. [Answer] Monestaries are places of great internal reflection. Much of what you see on the outside derives directly from what the monks feel they need to do on the inside. You are going to need to get inside the minds of the undead. In the comments, you say they want to venerate their dragon lords. What does that entail? Is that a massive expenditure of energy, such as the sacrifice of foods or burning effigies, or is that an inner activity that they could do for centuries simply standing still. In the case of the former, they still need resources. In the case of the latter, their needs will depend upon the precise nature of their undead-ness. You may want to choose to decide how much of their past life shows up in their nature. In many oriental martial arts genres involving warrior monks, much of what they are doing is trying to grapple with the untold atrocities they did before they realized they needed to find peace. A monk who has attached a great deal of death to his sword may find it tremendously useful to be able to use the sword in a way which brings peace and wellbeing to others. You could also choose to make them a bitter vengful group with a hatred for life. They would then become preoccupied with what it takes to keep life itself away from their core sacred temple. This could be a full time job, and have great implications for what sorts of structures are needed. [Answer] Well I myself also wasted a lot of thoughts on a topic like that. My undead community would have been a village not a monastery, but otherwise it was quite similar and I couldn't get it to work. Here are my thoughts on the subject: (Sorry if they are a bit messy, I gathered them from memory.) --- I assumed undead does not need to eat. That is kind of an important factor, since if they it they will almost surely be carnivores and - since no living being (sentient or not) would tolerate living beside an undead colony eating living flash, they would almost be a wanderer/nomad tribe. So no eating. I thought if they are sentient, they would have some clothing and furniture needs. After all no sleeping does not mean you don't like to sit down from time to time. Also, if you need clothing and furniture you will surely practice some craftsmanship which requires tools and special furniture like benches, tables, forges, tools like hammers and saws and like, and materials like wood, cotton, ore and maybe skin of animals. Since trading is out of question, they would need miners, agricultural workers, craftsmen and so, so they would have jobs to do. Also I assume they would need some protection from "heroes" roaming the lands, inquisitors and such, so having dedicated military is also a good idea. Another factor is if undeads lives are eternal. If they are, I would assume nobody would do the same job for an eternity (I guess being sentient means you **CAN** go mad.), so periodically they would switch roles. If lives are not eternal, then they must provide replacements by "recruiting" living people - something that definitely requires some sort of a military. Additionally I think an undead society also requires leader(s) who organize the work, but - since neither bloodlines nor wealth could not be a factor for obvious reasons - they would elect (by vote) or select (by some more radical way) their leaders. I would think sexual roles in an undead society would be more loose (because nobody gives birth, gender differences would be simply alternative body designs), so even a female leather - which is very rare in pre industrial societies - is possible. ]
[Question] [ Is it possible for an organism to evolve to biologically generate its own nuclear power? If so, how would this evolution occur? [Answer] ## They already have I'm not kidding. [Candidatus Desulforudis audaxviator](http://www.sciencemag.org/content/322/5899/275.abstract) (alternate [wiki link](https://microbewiki.kenyon.edu/index.php/Desulforudis_audaxviator) and [PDF paper](http://escholarship.org/uc/item/23x7d9r0) not behind a paywall) is a really curious species. It is a "single species ecosystem" which lives in deep fissures underground where D. audaxviator makes up so much of the total genetic content of the ecosystem that we have to consider that the remaining genetic load identified during analysis might be nothing but contaminants from our collection process. D. audaxviator has metabolic pathways to process the hydrogen peroxide generated by the radioactive decay of Uranium nearby. It, in every sense of the word, derives power from nuclear sources. [Answer] There are already organisms that have evolved to use nuclear power. Radiotrophic fungus are found inside and around the Chernobyl power plant. Fundamentally, there is little difference between plants that use light radiation to generate energy than organisms that use other forms of radiation to generate energy. Any sort of energy - heat, radiation, light, or chemical could potentially be used by an organism. It would also certainly be possible for some form of radiotrophic fungus / plant / algae to form a symbiotic relationship with other organisms like the relationship between Elysia Chlorotica and algae. Over time, this symbiotic relationship could develop to the point that the radiotropic fungi / algae become a part of the larger organism - similar to how mitochondria have been integrated as part of larger organisms here on earth. This could possibly create an organism that seeks and eats highly radioactive waste, or basks in levels of radiation that would kill the organisms we're familiar with. [Answer] Possibly a LENR reaction would be compatible with biological processes that we are familiar with. Though widely considered impossible, enough scientists still think that LENR actually exists and is able to generate lots of energy that it would seem reasonable for a Worldbuilding scenario. LENR reactions do not require extreme pressure or temperature and do not have the large radioactive byproducts that are so harmful for life. If LENR is real and the nanotechnology of biological processes could harvest the energy, it would seem a viable basis for a lifeform. There is a chemical poisoning problem associate with LENR materials since palladium, nickel, etc. are used. But, perhaps a LENR reaction could be based on a suitably engineered carbon molecule. This seems like the best choice for a direct usage of nuclear power by a lifeform that I can think of. To avoid life damaging radiation hazards you need something that either avoids the radiation in the first place - perhaps aneutronic fusion or such-like, or you must have a very powerful system of resisting and/or repairing radiation damage. Aneutronic fusion is unfortunately even more challenging than the mainstream fusion approaches. Any form of fission is loaded with ionizing radiation. If an organism could somehow harness Pu-238 or similar isotope in the manner of a [radioisotope thermoelectric generator (RTG)](https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator) perhaps it use this as an energy source. Pu-238 is an alpha emitter and is quite harmful, Sr-90 is a beta emitter, but still ionizing. The RTG is a very simply nuclear design, but the radiation is still a very real problem. The simplicity of an RTG is a major plus if you could justify dealing with the radiation and the ability to renew your supply of your radioactive isotope of choice. All RTG isotopes are necessarily short half-life and not present in significant quantity in nature. Then again, just how big can your lifeform be? If it is the size of a planet, good old uranium, thorium and potassium can generate plenty of heat and the levels are radiation are not very high -- just on that scale, the overall rate of heat loss is quite low. [Answer] Awkwardly enough, such a creature would be one that couldn't do much except channel that energy as quickly as possible. Think a creature with a drive to do something quickly, and that something would be massive, such as a zerg ultralisk from starcraft. Move as quickly as possible to get rid of heat and go accomplish a huge task, like destroy something, and then overheat and die when no objectives are left. This would be a cool weapon creature, but otherwise impossible to stop moving without overheating. Alternately, let the heat go free, like a Balrog. And it would be massively well armored to survive nuclear radiation. And... It would leave radioactive scat. [Answer] ## Dyson sphere Consider the possibility of a Dyson sphere with a single organism. Since the star would be entirely enclosed within it, it's reasonable to think of the whole system as one creature. That's a single organism with a fusion plant to power it. The single organism grew bigger and bigger until it overwhelmed (or incorporated) all other life. ## Power plant For a smaller variant, consider an abandoned fission plant covered in a lichen or fungus. Perhaps over time it accidentally adds more uranium to the core. This increases the heat output. As it grows, it finds more and more uranium and puts it all in the core. Perhaps you find these alternatives boring, but they're what I thought of given your description. [Answer] For fission, the heavy elements already exist, and are already producing heat, which doesn't quite match your description of "generate its own nuclear power". There are processes to speed up the breakdown of the elements so that they produce heat faster, but it's a bit far-fetched to imagine one of those processes taking place within a living creature. However, the overall concept of a creature eating radioactive rock and surviving off the heat they produce isn't impossible. A creature that survives on heat transfer and eats extremely heavy food would be unlike anything ever encountered on earth, so you're on your own, to invent that one. As for fusion, the only reactions that are known to work are "hot" fusion, requiring an enormous amount of energy to start, and in turn, produce too much energy to control (but they're getting close). It is pretty unbelievable that any creature would ever be powered by hot fusion. However, there are also a lot of folks who think "cold" fusion might be possible, where just a few hydrogen atoms somehow are merged and produce a little energy, which can be controlled. How and why the atoms combine is still a matter of science fiction.... but that makes it fair game for a science fiction story like you might be writing :-) If you write a story about strange little fish which are hot to the touch in arctic waters, eat almost nothing, have short lifespans, cause strange illnesses to anyone who eats them for too long, and produce a layer of air when kept in sealed tanks which changes your voice if you breath it, a clever sci-fi reader will realize you're describing a cold fusion powered creature. ]
[Question] [ I'm designing a computer game in a fantasy setting with dwarves who need to produce steel. This is a very traditional Tolkein-esque fantasy world at a relatively "middle ages" level of technology (no gunpowder for example). Detailed production chains are a big focus so I'm trying to keep things somewhat realistic (Is "hard fantasy" a thing?) and trying to design how dwarves (masters of working with stone and metal) would produce steel in this setting. I think it's not too far-fetched to think that [Huntsman's production of crucible steel in the 18th century](https://en.wikipedia.org/wiki/Crucible_steel#History_of_production_in_England) could have been employed in a less technologically advanced society in the real world, if the knowledge was there. So far I have the process as something like: * Mine iron ore from the mountain * Possibly need to grind this down and roast it * Produce fuel by turning coal into coke or wood into charcoal * Produce some kind of iron - **this is the part I'm unsure of** * Place the iron along with a flux in heated crucibles to produce steel I'm not sure exactly how the iron production, the key step to a smith, should go. Is direct reduction of the iron ore into "sponge iron" acceptable for use in this scenario, or would it need to be worked into wrought iron for use in this method? I guess sponge iron/a bloom of iron would contain too many impurities to use? Is there a better method I should be using? Some way that dwarves in this setting could avoid the labor-intensive working of iron into wrought iron? I'm aware of wootz/Damascus steel but I think it would be nice to have dwarves use the (more advanced?) crucible method to produce larger quantities than the medieval-level humans do in the same setting, is possible. Assume that the dwarves have a fairly large workforce of willing blacksmiths, as well as the ability to use waterwheels or windmills where appropriate. [Answer] Why not go full out and have them use blast furnaces and the bessemer process? **Blast furnace** This will get you iron. Blast furnaces were first invented in china in the first century, construction wise they are fairly simple. The biggest issue needed for a blast furnace is a powerful bellows which would naturally progress from engineering focused dwarves trying to get hotter and hotter flames or just trying to get fresh air into a subterranean city. It could even be an accidental discovery, to keep fires going underground without suffocating they will have to know how to reliably move air around. I can almost imagine dwarves cutting the furnace out of solid rock so it will last forever. Blast furnaces are still used today. You also need limestone flux and coal but again... dwarves. If anything they will start with a much better footing as mining is far more common for dwarves and the ability to extract the necessary rocks will be easier for them. Blast furnaces are fiddly but in the exact way dwarves would love; precisions mixing, close observation, and assessment of material quality. It also requires a big collective effort, which is perfect for dwarves. Bonus the slag from making coke from coal can be used as fertilizer and dwarven agriculture needs all the help it can get. [![enter image description here](https://i.stack.imgur.com/MMdw3.jpg)](https://i.stack.imgur.com/MMdw3.jpg) [![enter image description here](https://i.stack.imgur.com/5KqeU.jpg)](https://i.stack.imgur.com/5KqeU.jpg) **The bessemer process.** This step is more optional and individual dwarves could still make smaller furnaces. The bessemer process if used to mass produce steel from pig iron. It will make dwarven steel consistently better and as a subterranean race they will start with a better understanding of forced air processes necessary. In the early days the process was regulated just by looking at the fire, no fancy sensors necessary. It also favors coal as a fuel source over charcoal, which requires a lot of lumber, so again better for subterranean dwarves. Even the Spiegeleisen needed to make the best steels is just a matter of mixing iron ore and certain rocks together in a blast furnace. The only thing you really need is precise metalworking and stone cutting, which dwarves are supposed to be good at, and a small amount of metallurgy(chemistry) that they would likely have discovered anyway. Using a limestone or dolomite instead of clay lining for the furnace will result in a better product and stoneworking dwarves would certainly notice this. It has the bonus feature of producing fertilizer usable slag, which might explain how dwarves are able to grow so much with so little farmland. [Answer] The dwarfs best smelters use steam distillation of iron to make the best steel. They find certain magma flows that have a higher temp than the evaporation temperature of iron (iorn boiling point 5,184°F,2,862°C). This might be a bit of a factual stretch, since most high upper strata magma temps top out around 2,000°C but if they can figure out the fundamentals of heat transfer they could pump up the temperature of one stream of magma. They have stone tubes that guide the iron steam and it slowly condenses into liquid iron as it cools. They then add the elements they need to get the carbon into the iron. They cool it and are good to go. Simply using magma as a heat source to melt iron in minutes instead of hours or days makes dwarfs more efficient than surface dwellers. [Answer] I'm no expert, but i'll give it a try. As far as i know you mostly need know-how to make steel from iron. To make iron you [smelt](https://en.wikipedia.org/wiki/Smelting) iron-ore and then separate iron and slag (that's were the flux is used). Afterwards one can convert the iron to steel by using know-how, fuel and a special oven: [puddling](https://en.wikipedia.org/wiki/Puddling_(metallurgy)) Personally i think its far more "realistic" that a race like dwarves have a natural connection to stones and metal to have instinctual knowledge the humans needed centuries to discover. ]
[Question] [ **This question already has answers here**: [Evolution of giant floating mammals](/questions/34892/evolution-of-giant-floating-mammals) (6 answers) Closed 7 years ago. I have read about flying sharks that hunt birds and great monstrous flying whales, so I would like to know how a whale could conceivably start 'flying' in real life. I'm gonna just set [Blue Whales](https://en.wikipedia.org/wiki/Blue_whale) as the standard here, they are about 30 meters or 99 feet long and weight about 173,000 kilograms or 173 tonnes. I'm fine with making changes to their body and structure, as long as they still look like a blue whale and retain their size. Gravity and atmosphere would be the same as earth. They should probably be able to fly at around the same altitude as commercial planes at around 11km or 39000 feet. Try to figure out how big they can get too. I'm not sure they would be able get above the clouds tho. [![enter image description here](https://i.stack.imgur.com/htAnG.jpg)](https://i.stack.imgur.com/htAnG.jpg) [Answer] Note that whales have no wings, so they cannot fly like a bird or a bat; they would have to fly like a balloon or Zeppelin. Basically, you need to get their density down to less than the density of air. Since whales can swim under water, their density should be approximately that of sea water, which according to [Wikipedia](https://en.wikipedia.org/wiki/Seawater) is $1.025~\rm kg/l$. Air, on the other hand, [has a density of $1.225~\rm kg/m^3$](https://en.wikipedia.org/wiki/Density_of_air) — note the different unit. In other words, in order to fly, whales need to become lighter by a factor of about $840$. Or in other words, a whale that now weights $173~\rm t$ would then have to weight a mere $207~\rm kg$. That is, less than three average human adults. Since you excluded the idea of their body essentially being a big balloon (which is the only way I see it could work), I'd say there's no way to get what you want. External balloons would only work if they are about $840$ times the volume of the whales themselves, which would make them less like whales with attached balloons than balloons with attached whales. [Answer] With the constraints you have specified (Gravity and atmosphere would be the same as earth), the way to get something the same size as a whale to fly is to use one (or more) of three different methods: 1) Reduce density of the whale (as a whole) so it is lighter than air. This could be done by making the skin out of something super-strong and super-lightweight, and filling the whale with hydrogen or helium, or by altering normal whale tissue into something that resembles [aerogel](https://en.wikipedia.org/wiki/Aerogel). The book 'Tinker' by Wen Spenser did something like this. Size limit will be determined by durability of the body and stresses like high winds. 2) Apply a powerful enough force. Imagine a whale with a rocket strapped on. This would probably also require re-engineering the whale into a structure that could survive the stresses involved. Size limit will be smaller than the first solution even if you give the whales a skeleton made of exotic materials like carbon nanotubes. 3) Use a high tech or magical McGuffin. Antigravity, tractor/pressor beams, or magical weightlessness or flight. No limit on the size possible with this solution since your solution can be as wild or as improbable as you like. The first two are science/engineering approaches (i.e. possible in our universe), the third requires your ability to alter your universe (since this is world-building). If you combine more than one of these solutions, the maximum size of your whale will be larger, but in general the problem will be designing a structure strong enough to deal with the stresses of flight. In real life, whales can get as big as they do because they are supported by surrounding water, which is why they can be bigger than any land animal. [Answer] If you can't fit the whale with wings, turn it into a big balloon, reduce gravity or make the atmosphere really dense, then your options are limited. The [Antonov An-225 Mriya](https://en.wikipedia.org/wiki/Antonov_An-225_Mriya) would be able to lift that much weight (maximum total payload 253,820 kg versus whale-weight of 173,000 kg so no problem there) - the question is, would the whale fit in the payload bay without needing to be chopped into pieces? > > The aircraft has the spacious cargo compartment with length of 43,32 m, width of 6.4 m and height of 4.4 m > > > [Antonov: AN-225 Mriya / Super Heavy Transport](http://www.antonov.com/aircraft/transport-aircraft/an-225-mriya?lang=en) So we should be OK on length: > > up to 30 metres (98 ft) in length > > > [Wikipedia: Blue Whale](https://en.wikipedia.org/wiki/Blue_whale) It's hard to find data on the width of a Blue Whale's tummy, but if we assume it's no wider than the tail, then we should be ok: > > The width across its tail flukes (flippers) is about 6m (20 feet) > > > [Cool Antarctica: Blue Whale](http://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/whales/blue_whale.php) and on height we do seem to be roughly in the ballpark. So in summary, this method meets the criteria in the question and should work OK, although the whale might have trouble squeezing its waistline into the plane - it might need to go on a diet first. If you could choose a slightly smaller whale, that would be helpful (173,000kg is particularly large, even for a Blue Whale). You would need some way of helping it support its own weight out of the water, of course... (perhaps you could use the additional available payload weight to surround it with some kind of gel?) and some kind of a [brain-computer interface](https://en.wikipedia.org/wiki/Brain%E2%80%93computer_interface), assuming you want the whale to pilot the aircraft itself. Alternative answer: [drop it from a really high place](http://www.imdb.com/character/ch0007558/quotes). [Answer] You'd have to have it full of lighter than air gas, if you want your whale to fly. Your other options are to cover it in stiff armour, so that its spine doesn't snap under its own weight, or a series of wings along its length to provide uniform lift. Both these options are energy intensive, not least since they involve adding to the mass of an already huge load. Far better to have an inflatable bladder that it can fill with hydrogen, generated by bacteria in its gut, to compensate for its own weight and have wings evolved from flippers for propulsion. If the bladder extends along the length of its body, the only support the skeleton needs to provide is against air pressure. Thus, the bones can become hollow and so, lighter. The blubber is needed for insulation, especially in the jetstream, but the amount can be reduced. Instead, you'd want a hardened outer skin to withstand the cutting (and drying) effect of high winds. Food will be an issue, unless you also have flying seafood. This is what will limit the size and number of your whales. The more effort the whale spends per kilojoule (or kilogram) of nutrition obtained, the less there is available for growth. ]
[Question] [ Pennyless Joe, the broke archeologist, finds an old pawn shop selling something curious. A ceramic vial labeled "Groundhog Day Potion". It's a bargain for $1.99. (He buys it, because he is not quite that broke). Pennyless Joe is very intelligent (though not financially savvy) and well versed in archeology and alchemy. After buying and studying the potion sample, he learns that the potion is real, still potent and allows the imbiber to "Groundhog" - relive an entire day with full memory of what happened on the first iteration of that day, but you only relive the day a single time. He also knows there is no way to duplicate the potion, because it requires a long-extinct herb and the magic in the potion will be spent at the start of the replayed-upon day. But alas, by breaking the seal, the millennia old potion begins to lose potency. Pennyless Joe's alchemical knowledge tells him that the potion will only be useful by December 24th of 2016. So Penniless Joe wants to use the potion to reverse his wealth predicament, and make the most cash out of this single day. what should his winning strategy be for this one day, to get really rich? --- EDIT: This does not break or invalidate any answer already posted at the time of this edit so: Penniless Joe does not have much money on him after buying the $1.99 potion. He does have an income, but it barely meets his monthly expenses. You can make any assumptions about his credit rating or any other ease/hardness of obtaining credit. Also keep in mind that he has one year to use the potion. P.S.: please do not answer with some potion-duplicating infinite loophole. It is intended to be a single-use artifact. [Answer] With only a single day's knowledge, and a single chance to exploit this day's knowledge, the correct answer would almost certainly be lottery tickets. There are few - if any - ways to make a short term 'profit' on a par with gambling, and knowing the day's lottery numbers is the only way that would really be possible for an individual to accomplish in the repeat of a single day. Many iterations may allow more theoretically profitable opportunities (such as repeated wins at casino games), but Joe would only need to memorize a single sequence of numbers to win the lottery - something completely doable in a single day. Ideally, Joe would play and win the lottery multiple times in a day (Pick-4 in the afternoon, reinvest in bigger payouts later) but the fixed maximum payouts on a single lottery would probably limit the value of that strategy unless Joe could play multiple different lotteries all at once. Of course, if Joe's trying to accomplish this without attracting any attention (once the day ends and he's back on regular time), simply playing the single largest lottery once would be the way to go. [Answer] Joe must locate wealthy individuals with terminally ill or dying relatives, offering 'one more day' in exchange for the personal wealth of the individual. Joe may not be able to look at himself in the eye ever again but a mansion doesn't really need mirrors, does it? Simply ensure the paperwork is in place the day before delivery of the potion - so the recipient re-lives the next day. [Answer] Getting away from the normal kind of gambling, he should short sell stock. Find a few stocks that have massive daily losses at the close of the market. On the loop day sell the stocks short. Cover the shorts as soon as the market reopens after loop day. This has a benefit over buying stock because you need to have money to buy the stock, which Joe probably doesn't. This has a benefit over the lottery because there might not be a mega millions lottery on the day he happens to open the vial. Make sure you pay your taxes. **Edit:** How to convince a friend that invests that you're not full of crap: On the 22nd talk to a friend and have him choose between 3 and 5 stocks, write down the ticker symbols, but not tell you what they are, with the understanding that you'll either call him at 7 in the morning to tell him the exact price the unknown stocks he chose will be at 11 am, or that you'll call him at 11 am to find out what the ticker symbols are. On the 23rd (first pass) wait till 11 am and call for the ticker symbols. Write down the prices for those symbols. Then wait for the close of the market to see who you should short. Maybe consult with your friend to get some input on what ones are the best. On the 23rd (second pass) call your friend at 7 am and tell him which stocks he chose, and what the prices are going to be. At 11 am call him and tell him which stocks to short. On the 24th close the trade and split the profits with your friend to the agreed upon amount. [Answer] The best plan for maximizing your wealth in a single day involves the following. **Pre Planning Steps** (not in any particular order) 1. Pick a very busy day in sports, in the United States this will likely fall sometime in Autumn when you have professional and college football, professional baseball, professional basketball, hockey...etc. 2. Take out a large reverse mortgage on penniless Joe's home 3. Travel to Vegas. Spend the very busy sports day documenting all the games being played. (it would help if you can carry over a notebook from one day to the next, but if not he could get the scores and stuff tattooed on himself). 4. Spend some time with a few high rollers in the casino and keep track of their day to convince them on the repeat day you can make them a lot of money if they invest in your day. 5. Find a stockbroker in Vegas for ease of access when you choose to repeat the day. Again, make sure they know you, call them and see what things happened during their day so the next day you can more easily convince them to maximize your time/money. **Repeat Day** 1. Get up really early, meet with the whales and call your stockbroker to get them in on the plan. Take your mortgage money and any cash from the whales and invest in the market based on what you know you can make, waiting for a day where there were big changes will obviously make you more money. 2. Use some of the money to hit sports books around vegas and spread your winning bets around (no one wants to get broken bones by making a casino think you are cheating) bet big obviously the crappier the odds the larger the bet...putting it all on one bad bet you know will come through is efficient but...spreading things around should draw less attention...until tax time at least. 3. Enjoy the day, have some drinks, gamble (though I should mention that gambling won't be certain since you are likely creating an alternate reality by gaming at table...where you change the dynamic as opposed to sports and lotto betting) 4. Bet the lotto...obviously. Wait for a large jackpot that no one else wins (no one wants to share a jackpot afterall) 5. Hire a wealth manager 6. Profit... 7. Visits from the NSA, FBI, IRS, and other agencies who are going to be very very suspicious... [Answer] Joe thinks about lottery or casino first, but he is intelligent and he has read about the [chaos theory](https://en.wikipedia.org/wiki/Chaos_theory) before and he has a nagging suspicion that not just a butterfly might flap her wings differently, but the mere breathing differently might cause variations in thermal noise of the lottery machine, and it's quite probably the numbers will be different the second time (and it's almost guaranteed with the roulette, especially the electronic kind that draws randomness from quantum noise). Oh, he will buy a few tickets, just in case. OTOH, stock markets (or even better [forex](https://en.wikipedia.org/wiki/Forex)), are less random, more dependent on general trends. So he will spend the time familiarizing himself with the forex operations and then put everything into the financial operations. Unfortunately, being penniless, the most he would be able to invest is his monthly salary (just after he receives the cheque). The exact nature of the potion is important - if he drinks it, will he relive the previous day until the drinking, or the following one? In the first case, he might wait for some unexpected big changes in stock market or foreign currency [like this one](https://www.investopedia.com/articles/forex/052815/swiss-franc-good-investment.asp). Unfortunately, he'll never know if there's not something better tomorrow, but if he waits for too long he might never get better opportunity. [Answer] Roulette. Go to a casino, note the numbers that come up. Go back, spread your bets around enough that it's not so obvious that you're making a mint. Continue until the casino throws you out. ]
[Question] [ > > If you were to do a plane or world where music interacts with everything and instruments are essentially able to influence reality based on how they are played, what would be the practical difficulties? Where might such a world fall apart, and what would you suggest as caveats to prevent that from happening? > > > I am breaking this down into areas of interest, as it was stated to be too broad as a single question. Assumption: Sound has the power to influence everything in the world. The percussion of your footsteps temporarily discolors the ground, the tone when you speak stirs the air, the chopping of an axe against a tree causes the forest to actually shudder. Music or harmonics have the ability to cause larger effects. Issue 1: Vibration Q. If the impact of sound causes vibrations that in turn can cause sound, how might you limit the ripple effects to maintain a functional world? Issue 2: Scale Q. If a drum can influence the world, surely a volcano or a thunder storm are even more exciting than normal. Controlling for scale seems important, but how to codify such a control? Issue 3: Animals Q. Many animals make appealing noises and sounds, and it can be assumed in such a world that the number of animals who adapt to exploit the harmonic nature of the world would increase. What impact might that have on a broader sense? I'm envisioning a murder of crows being a truly frightening sight. [Answer] The main effect would be that people would make far less music. Music is dangerous, and therefore not the sort of thing people would engage in without purpose. Once that's cleared up, it really just works the same way that magic does in any other setting, maybe it's secretive and only taught to a few in fancy colleges, maybe the world is speckled with hedge musicians who teach by apprenticeship, maybe whatever other system you come up with. Issue 1 (**Vibration**) is largely a non-issue. The vibrations created by sound create far less sound than it took to create them. Sound still dies out. Issue 2 (**Scale**) can be controlled by just having the effect of major natural noises being the same as the things that cause those noises in the real world. Lightning is caused by thunder instead of the other way around, with the source of thunder being some mysterious process in the clouds. That keeps those sounds appropriately impressive without breaking things. Issue 3 (**Animals**) mainly comes down to animals developing specialized organs to make very specific sounds, even more so than they already do. This would have no major impact on the nature of the ecology as a whole, it would just mean that some predators shoot lightning instead of ripping things apart with claws. Note also that most animals would try to avoid making sound as much as is possible outside of specific sounds they intend to exploit, since they are even more likely to draw unwanted attention than in the real world. [Answer] **1) Vibration** If you hold to the conservation of mass & energy, then the sonic energy output of a given reaction would be less than the sonic energy input, before you consider the potential energy released. I would assume that releasing potential sonic energy would be quite important to your world. Much as generating a spark to light a fire or tipping the first domino of an impressive display, the use of sonic energy to amplified effect through stored potential sonic energy would be a goal of those seeking power. Your world might have the equivalent of WMDs in those songs/tones/harmonics that produce such amplified effects. For example, a specific wail might cause stone to rend and scream in agony, which triggers a chain reaction in neighboring stone to the point of causing a mountain to explode in a cataclysm of rock shards. In other contexts, however, many reactions may well be defensive and specifically dampen the effect. For example, shuddering trees might cause a sound inverse to the axe's chopping so as to limit the number of trees that suffer from the sound. **2) Scale** Reversing cause and effect, as suggested by @Saidoro, is an excellent choice. Having thunder cause lightning and a tremendous roar cause a volcanic eruption will emphasize the place that sound has in your world. This also opens up dramatic tension where a dormant volcano begins roaring and everyone knows to flee, or better yet, attempt to counter the sound, perhaps with calming songs that quiet the earth and lead to peace and stability. The [inverse-square law](http://en.wikipedia.org/wiki/Inverse-square_law) also helps to explain potent local effects from relatively low energy (human voice) while not having the world end with the first volcano. Because it takes 4x as much energy to have the same effect at 2x the distance, an incredibly load/potent sound that is 100x as loud as what is required to kill everything within 3 feet will "only" kill everything within 30 feet. You need to get to 10,000x power to reach 300 feet. Decibels are already on a logarithmic scale to help with such comparisons. **3) Animals** Silence would be even more important for most animals to avoid becoming prey, as noise would leave greater evidence of their presence. Animals would also, presumably, develop even more specialized sound-producing organs to assist in hunting, defense, and every other aspect of survival. For example, rather than a beaver that has teeth designed for cutting wood, you instead have a creature that can sing the song that bends trees to one's will to build living structures of wood. Just as animals have highly developed physical predator/prey equipment, such as teeth, claws, muscles, hide, etc., I would expect highly developed sonic abilities. Presumably human beings will be the top predator in large part through musical instruments and other sound producers that permit human beings to generate sounds far beyond the capabilities of another animal with similar lung capacity/strength. [Answer] > > If you were to do a plane or world where music interacts with > everything and instruments are essentially able to influence reality > based on how they are played, what would be the practical > difficulties? Where might such a world fall apart, and what would you > suggest as caveats to prevent that from happening? > > > This is an extraordinarily complicated question, but -- with all due respect -- the first clarification or moderation applied to the question has taken it in what I think is a problematic and overly narrow direction. Music is not intrinsically about vibrations, sound, pressure, or anything like that. It is what it is. See Plato's various discussions (often highly negative). Music affects people, or the world, because it does. Now you have to immediately ask, "why?" That could be because of vibrations or sound or whatever, but it could be because of harmonic relationships. For example, you could say that any absolute relationship of 1:2 or 2:3 has an automatic effect on the world, because in fact, normally speaking, nobody and nothing ever gets close to such precise relations. We always approximate. So we try to build a house that's twice as long as it is wide, but in fact we get kinda close to a 1:2 but not really. Thing is, we can tune an interval very precisely, because if we put a bar on a string at nearly 1:2 (5" from one end, 10" from the other), and vibrate the string, we can roll the bar up and down until our ears tell us that the relationship is getting closer, and then any ear that isn't actually tone-deaf can home in on the correct relation until we get very precisely to 1:2. Or 2:3. 3:4 is trickier, but not by much. And that gives us octaves, fifths, and fourths, and they are perfectly (justly) tuned. And that is not normal: few if any other relations in the real world can be "tuned" so perfectly So why is that? Well, maybe it's because the universe is structured around these special relationships, but only music is able to bring them to the fore. Or maybe it's because the Gods like music, and have infused its basic relations with special divine qualities. Or maybe it's because the stars are exactly in those sorts of relational distances and aspects, and this reflects down into the sublunary world through music -- in which case, why music alone? So far, all this is pre-created: this is Greek music theory 101 through elementary medieval European music theory 101. And I do mean 101: you have no idea just how complicated this stuff could get. But to answer the question: why does music affect the world? Because the world is built on musical relations, from soup to nuts; more accurately, Creation itself is built on those relations. When we perform or play or think about musical harmony, we are tapping into the structure of the universe itself. Nothing else but pure Euclidean mathematics (which has no real-world analogy) is like this. So... What are you trying to explain, exactly, and how does it work in your universe? Because I can explain music having pretty much any implication you want, without having to invent anything whatsoever. You just have to realize that "music" does not mean "sound": it means complex mathematical relations that may be expressed sonically but are weirdly drawn toward perfect integer relations... just to begin, at least. **Background Thinking** Bear in mind that the category "music" is in no sense obvious or automatic. While we know of few if any cultures whose people do not produce something we in the modern West would classify as "music," we also know of few if any cultures that have a category or classification that maps the modern Western "music" at all smoothly. To give the obvious example (which also lines up with my previous remarks, historically), in the Middle Ages, "musica" (Lat.) was classified together with astronomy, geometry, and arithmetic; these are the quadrivium, the topics of study and analysis founded in the nature of the Creation as God chose to make it. Then you have the trivium -- rhetoric, grammar, and logic -- which are the topics founded in human thought and arbitrariness (in the technical sense). The reason "musica" was in the quadrivium and not the trivium was not only that "musica" is rooted in harmonic relations and so forth. It's also because what we usually mean by "music" today was a narrow subset called "musica practica," music as it is actually done in human life. And this was deemed uninteresting, unimportant, and largely insignificant, because what's interesting and important about music is how it is embedded in the Creation, NOT what you happen to hear somebody singing on a streetcorner. The point is, again, that clarification is needed. At base, "what if music is really super-important and powerful" is not a hypothetical question; it is a historical one. But it's not necessarily a physics question, and it certainly is not a matter of weaponizing sound. In order to dig into the issue more deeply, you have to consider just what you mean by "music" as opposed to "sound" or "noise". [Answer] I would start with some assumptions: * The nature (as in not living things) are unchanged. Vocanos erupt, lightening strikes, etc. * Sound creates a reaction in matter which causes *visible* light to be emitted (in reality, sound can cause things to heat up, which emits infrared light, so this new world will have something similar, but greatly amplified) * The technology has progressed at least as far as the world today. * Harmonics, or pleasing sounds to human ears, have a far greater effect than dissonant sounds (as per OP) * All movement creates a little sound (this is true in our world) * Sound can be bad, harmonics are unimaginably worse. # Human interactions Language would be vastly different. If spoken language exists, it would be very different to what we experience today. A form of sign language could be a possible adaption to having such a dangerous organ (the voice box). If humans developed a spoken language, they would be careful not to speak over each other, as accidental harmonics wouldn't be pleasant. A baby would soon learn that shouting loudly would hurt, so they wouldn't shout. In fact, any kind of hearing would become unnecessary, since all sound has real consequences. As has already been mentioned, music would be limited. The natural instincts of parents would be greatly altered. Humans who learn to whistle and sing at the same time would have unnatural power. However, it's quite possible their lips would become calloused (as a guitar player's hands do) from the vibrations. Inner mouth shields could possibly be developed to bounce sound out of the mouth instead of going into the head, allowing for stronger sound output from the mouth. This also has implications for impressive 'concerts' involving light shows similar to fire-spitting performers. Also, martial arts involving harmonics? TV's etc. would likely not produce any sound as something that is designed to be on for long periods of time will eventually cause damage to the surrounding structure. Also, accidental harmonic resonance with the surrounding environment could cause unwanted destruction. This leads to several questions about communication in general. Assuming sign language takes over: * Would the telephone be developed? What would it be (weapon/excavation technique)? * Would the jump to video communication be possible? (e.g. technology progression something like light signals -> morse code via light -> video communication) Assuming voice communication happened: * How would the telephone be different? (perhaps there would be a box to speak into so that sound didn't leak out to accidentally destroy people) # Animal interactions Herbivores would avoid sound at all costs. Creatures such as hummingbirds would likely not exist, since they would likely damage flowers/each other etc.. But if you're not being too careful with physics, it would be interesting to see the light come off their wings. Birds would focus on large wing structures to avoid unecessary flapping. Insects may be very different (imagine how easy the life of a predator would be when it's food literally lights up like a christmas tree). Possible insect adaptions include: * faster reproduction (to avoid predators) * The swarm creates directed sound at the predator, each member of the swarm creating a different frequency, so that all of them meet at the predator. This would make many many harmonics in a tiny space (think explosion). * a lot more walking involved, flight only as an escape mechanism * becoming poisonous or physically difficult to eat (e.g. spiked) Other herbivores may adapt to use vibrations to knock down fruit etc. from trees. Predators would also rely on being as quiet as possible, but catching prey would look magnificent. Subtle adaptions could include multiple resonance chambers in a thick skull to frighten prey or even incapacitate at close distance. # Nature, and human adaption to it Places that frequently earthquake or lightening would be out of bounds. It would just not be plausible to live there. If anything lived there would either fly or do something to disconnect it from the vibrations. Sounds that cause sounds etc. would naturally dissipate, although likely much more destructively than our world (as mentioned before). The side effect of this is that sound would travel much less in media it could destroy. For example, you might not hear a pot falling in the kitchen upstairs, but you might find the pot melted and the ground dented. You would build floors that don't break so easily. Avalanches would likely become earthquakes, but again, the energy would travel less. But the mountainside might take a hit because of the sound. # Summary ## Issue 1 Sound would dissipate more quickly so it wouldn't travel as far. In solid media, sound would likely cause more destruction (and therefore travel less). ## Issue 2 Intelligent beings would likely deal with the issue of scale themselves and naturally avoid dangerous circumstances (much the way humans avoid overly hot or cold climates). ## Issue 3 The most pronounced change would be that animals would try to eliminate sound as much as possible. Anything that gives away an animals position is usually a disadvantage in the wild. Packs of animals could destroy prey/trees/rocks by emitting sound from different points in space aimed at the same place. [Answer] My first assumption to this would be (to keep things from escalating) that the sounds would be absorbed as part of their affecting other things. So the crunch of gravel coloring the ground quiets the crunch by absorbing some of the sound into the discoloration. These kinds of reactions could go both ways, sounds could be absorbed most of the time, or amplified or 'rebroadcast' if pleasant sound like singing or a warning like an ax against a tree. At least from things with a 'living aura' might be able to amplify or 'push/rebroadcast'. [Answer] Well, there is such things as [Harmonics](http://en.wikipedia.org/wiki/Harmonic) and [Resonance](http://en.wikipedia.org/wiki/Resonance), which helps explains some of the more crazy things that sound can actually *do*. Those links are good background reading for this sort of thing. **Issue 1: Sounds causing sounds, which cause sounds, which cause...** This can be very easily solved with energy. Even in physical systems in which resonance is happening, you still need to put energy in before stuff breaks. Do you have a horn that causes walls to break up? Well, you need a bigger horn to break more wall. You can even say that you need a basic amount of energy in your sound (well, an [intensity](http://en.wikipedia.org/wiki/Intensity_(physics)) at the receiving object) for the receiving object to make sounds. Also, the sounds made by that object need not be of the same frequency as the initial vibration; there can be dampening effects which stop hinder the magic. **Issue 2: Scale** This is most easily solved using resonance. Sure, a drum may have the right frequencies to cause a certain magical effect, but a thunderclap does not. This, once again, relies on harmonics. If big sounds cause certain effects, then you better make sure that whatever is living there can survive those effects. **Issue 3: Animals Using Harmonics!?** Well, animals *would* use this to their advantage. Plants and animals seem to exploit [all](http://en.wikipedia.org/wiki/Gecko#Adhesion_ability) [sorts](http://en.wikipedia.org/wiki/Mantis_shrimp#Claws) of [physical](http://en.wikipedia.org/wiki/Sense#Electroreception) [phenomena](http://en.wikipedia.org/wiki/Sense#Plant_senses) to gain advantages. You may even see some creatures invest in forms of [soundproofing](http://en.wikipedia.org/wiki/Soundproofing) or [noise cancellation](http://en.wikipedia.org/wiki/Active_noise_control). Obviously, creatures who make a wide range of sounds would have an advantage here. [Answer] Considering the much larger scale of the effects of sound in this setting, I would assume some drastic differences, primarily adaptations to *reduce* the influence of sound on the world: *( Keep in mind, I'm assuming we want to maintain a world resembling what we know - Honestly, for sound to be this effective, the world would be unrecognizable )* Overland materials, such as rocks, trees etc. would probably be more porous or softer, to avoid being shattered and torn apart by intense sounds during heavy weather or the concentrated effects of animals using sound as a means to hunt or influence their environment. For rocks, this would be because you'd only see rocky material that is soft and sound-proof enough to maintain structure for long periods of time. The surface might be quite sandy as well. Winds could be quite intense, especially during weather phenomena and even worse during volcanic eruptions. Specifically: Q1. As mentioned above, the world would adapt, so would biology to dampen sound; you'd see a lot more soft materials covering familiar natural structures or said structures being composed entirely of sound-dampening materials (or they would more often exclude sound-trasmitting mediums) Q2. The cause reversal already proposed should work well enough Q3. Animals would again not only develop a lot more sound-centric tooling and weaponry, but would also develop sound-dampening significantly. You might not see as many hard-shelled creatures, but you probably wouldn't see *more ears* (since the reason sight is preferred isn't just because light is so prevalent, it's also because it's very efficient in providing information, compared to sound). I'd also like to repeat Saidoro's assumption that music would be far less prevalent - this isn't because it isn't appealing, but if a drum can cause havoc, it would be like using a gun to paint (i guess). But there would also be a lot more use for music as a tool. [Answer] One thing I've not yet seen mentioned is communication (both human and animal). Using sound (especially loud sound like a warning cry) to communicate may be a bad idea if it can have all sorts of side effects. So probably other communication channels would develop to be used in preference to acoustic communication; maybe optical ones where the skin colour can be changed (like a chameleon, but faster) for sending signals. On the other hand, maybe the side effects of sounds are used to have a greater effect than the sound alone (if that is the case, the aforementioned warning cry would actually be a good example where it might be desired). People would also probably not speak acoustically to each other. They may have developed sign language; however they also might have biologically developed an optical communication channel (skin colour/patterns, bioluminescence) sophisticated enough to be used for language. Generating sound would likely be restricted to actually manipulating the surrounding. Probably the idea of communicating with sound (i.e. speaking) would be so alien to humans that few would ever even think about sound as a possible communication medium. [Answer] It is for most cases easy to dampen sound, and that probably would be a requirement for all tasks performed. Axe-handles would probably be designed to absorb vibrations (and therefore sound), or certain actions would have to be taken beforehand, like putting up sound absorbing walls around the tree. Shoes would have a very soft sole to prevent noise from walking, and things like metal necklaces would be generally unheard of. Everything can can make noise would be carefully designed to serve a purpose, so drums would probably not exist, except for those that have been carefully designed to cause a very specific sound for a specific purpose. If very loud sounds (thunder crack) could have wide-spread devastating effects, such a world could have never survived, so there must be a reason why certain sounds just won't cause havoc. A possible reason could be that it requires a melody for a certain effect (which would also counter the wood-chopping or walking). Or the effect of such noises would actually be beneficial, for example the crack of thunder could cause water to appear, which then explains the rain. Animals would adapt and send out sounds that fulfills their purpose. Most animal noises that can be heard at night (in the real world) are made to lure potential mates for reproduction to them. Maybe the effect would be much stronger in your world? A roar of a defending animal could cause fear to be applied magically on the target. Also most animals would completely rely on sound as their offensive and defensive abilities, as there is no need for claws, if you can just whistle someone to death. There would as well be a strong effect on society. If speaking, singing or even knocking on something could cause magic effects, the world would either be very a savage one, or parents would spent much time on educating their children on how to be responsible when using such powerful magic. If you imagine to give every child in the real world a real fairy that fulfills their wishes, then many things would be very chaotic. [Answer] A dimensional rift would be useful. Basically you can have a world 'in the balance.' Different sounds can cause rifts to different worlds depending on their tone and pitch. The size of the rift depends on how amplified the sound is. It would bring a whole new meaning to the word 'hush.' [Answer] **Who says this doesn't already happen?** Quantum physics actually *is* the world you are describing. The QM model is based on the fundamental assumption that everything is model able as a wave, known as a quantum waveform. Everything you are looking to have happen actually occurs in QM. So why don't we find the world we live in looks like a bunch of harmonic waves? It actually does look like a bunch of harmonic waves in areas termed "linear." Motion of objects through air at high speed are often best modeled using waves and harmonics, actually. The issue shows up when something behaves non-linearly. QM suggests that everything is actually linear, but the "reality" is so complicated that *actually* modeling the world in this way is too computationally expensive and too hard to measure. If you accounted for the exact state of every proton neturon, etc. in the entire universe, and constructed a quantum waveform for it all, you could actually view the world as a bunch of harmonics! In reality, we find non-linear models do a better job given our imperfect view of the universe. We like the idea of particles colliding, because it matches well with our billiard-ball style intuition of how things should work. So you'll probably want to look at what QM does to solve this. The solution of choice is called a [Wave Packet](http://en.wikipedia.org/wiki/Wave_packet). A wave packet acts like a snippit of a wave with some location. It is easy to show that QM lets you break apart the universe's waveform into a bunch of these little wavepackets (with a few minor caveats). Wave packets are neat because they exhibit "wave/particle duality." In highly linear situations (like a photon traveling through air), the coherent wavelike part of the wave-packets becomes the most driving part, and we see wave like mechanics (which we *do* see in photons traveling through air). In highly nonlinear situations (like when you use the photoelectric effect to generate said photon to fly through the air), the importance of the wavelike behaviors gets downplayed because there's too many non-linear effects. The importance of position begins to drive, and we see particle like mechanics (which we *do* see in photons emitted in this way). A QM lesson in a nutshell, the famous "[single photon double slit experiment](http://en.wikipedia.org/wiki/Double-slit_experiment)" is so interesting because the creation of the light is best modeled as a photon (a particle), but its behavior in the rest of the setup is best modeled as a wave (a lightbeam), so both models break down and give bad predictions. Only the full QM waveform model is strong enough to properly predict the uncanny results of that experiment! So what do we expect in a world based on harmonics? This says that a "consistent" world with an emphasis on harmonics will avoid non-linearity. You won't see a hard wall (like the echo-y concrete surfaces of an underground tunnel). You'll see soft walls which seek to minimize the non-lineary of the situation (nuclear submarines are coated with a rubbery surface whose job is to minimize the nonlinearity between the water and their hull, so they make fewer echos). You would not find people discussing the truthood or falsehood of ideas, but rather find them discussing the harmony of ideas, and balance. So, given these general principles that lead to a world dominated by harmonics, what might your particular questions yield: > > Issue 1: Vibration Q. If the impact of sound causes vibrations that in > turn can cause sound, how might you limit the ripple effects to > maintain a functional world? > The concept of "impact" you are looking for implies a non-linearity. Accordingly, you would see more of those submarine style surfaces which damp the ripples. > > > Issue 2: Scale Q. If a drum can influence the world, surely a volcano > or a thunder storm are even more exciting than normal. Controlling for > scale seems important, but how to codify such a control? > > > There are two scales in mind: size and loudness. Loudness would be a simple issue to control: louder things do more. Your intuition for soundwaves would be sufficient for this. The issue of drums size vs. a volcano's size gets interesting, because theoretically it only matters in one place: its hard to generate high harmonics with a large object, and hard to generate low harmonics with a small object. You would expect to see different "flavors" of effects. What makes drum/volcano interesting to me is that it starts rapping on the edges of the wave/particle duality issue. If the world is perfectly linear, its size matters little. However, such worlds are not very realistic nor fun for readers. In a world which is simply *more* linear than ours, emphasizing harmonics more, there are still some nonlinearities. This leads to something which has been found important in many worldviews: a drum usually is drown out by a volcano, but a drum struck with the right feeling and in the perfectly right place can shift the world. I would expect that, in a harmonious world, there are fewer places which such nonlinearity can be exploited, and they have less of an effect. However, they would exist, or else drums would be a far less interesting part of your story. As a clear example: if you beat a drum and nobody is around to hear it, does it have a large effect? Now do the same beating of the drum in a crowd, it has a much larger effect. Clearly the presence of people causes these non-linearities to become important. > > Issue 3: Animals Q. Many animals make appealing noises and sounds, and > it can be assumed in such a world that the number of animals who adapt > to exploit the harmonic nature of the world would increase. What > impact might that have on a broader sense? I'm envisioning a murder of > crows being a truly frightening sight. > > > This could actually go either way, depending on how you want to sell your story. In one direction, you could argue that the sound of crows is *very* discordant, so its effects would be more poignant in a world that is highly reliant on harmony. In the other direction, you could argue that these crows exist in this new harmonious world, not our world, and the crows would probably have a commensurately harmonious sound (generating the same feeling of cacophony we feel in our world by emitting a more harmonious sound received by ears that demand more harmony). ]
[Question] [ In a world inhabited by primitive hunter-gatherer humans and dragons, one of the most respected trial by fires is to hunt a dragon by jumping through their mouth and killing it from inside the stomach. Understandably, the survival rate of such a trial is not high. However, the question arises, how big would this dragon have to be? **The hunter has to know the minimum size of dragon to find for their trial, otherwise they could get stuck halfway**, and nobody alive wants to be stuck in a dragon's throat. Knowing the minimum size would also help the hunter find a suitable dragon easier, and it is also easier for a hunter to perform the feat on smaller, slightly weaker dragons than a behemoth. This could also be useful information for their rivals. Oops. Who could have predicted the dragon was just a size too small? --- **The question: given the shoulder length of a human warrior, is there a rough formula for the minimum size a dragon has to be, for this human to be able to go through its esophagus and into its stomach?** Details: * the dragon has the same internal organ to body proportions as a standard lizard * externally, dragons have the same form as a standard lizard, difference being wings and a flamesac for fire breathing * size would be for the rough height, width, and length of its body and head, excluding its tail and wings. * the dragon's esophagus is the right diameter for that person to slide through with an allowance of +/- 5%. Sometimes you just have to squeeze through. * you can use metric or imperial for size. Assume the barbarians know unit conversion and politely measure dragons for suitability before each trial. * don't worry about the stomach acid. This is why it is called a trial by fire. Example: * If you want to use calculations, you can use Billbo as an example. He is a healthy male of height 180cm, shoulder width 41 cm, and 71 kilograms of weight. Diagram of a Dragon without its flamesac and wings: [![enter image description here](https://i.stack.imgur.com/d2dUA.png)](https://i.stack.imgur.com/d2dUA.png) --- Derived Algorithm from Answers so far: > > Referencing Emilio's answer, the total length of dragon needed for a Billbo-sized hunter to do the trial for **is 31 meters, the rough length of 2 sperm whales**. > > > > > Thus, with Billbo as a reference, we know we require roughly **2 sperm whales of length per 1 Billbos, which equals 2**. *We call this number the Billbo Constant*. Hunters can find their width in respect to Billbo, and multiply it by the Billbo constant to find how many sperm whales in length the dragon has to be. > > > > > Let's use Jojoe, the widest man in the tribe, as an example. Jojoe prays to the tribal gods before finding the great Billbo to compare lengths with. Jojoe finds his belly is 60 cm in diameter, versus Billbo's 41cm shoulders. With this comparison, **Jojoe knows that he is 1.5 Billbos in width**. He multiplies it by the Billbo Constant of 2, and knows that he must find a **dragon that is at least 3 sperm whales from head to tail**. Confident, he goes off in his adventure, *mostly* sure that he will not meet an ignoble end as a fishbone in a dragon's throat. > > > [Answer] **31 meters long, from head to tail.** I pasted your Diagram of a Dragon in MS Paint and inserted a straight line across the narrower visible section of the esophagus, right next to where the trachea gets touched by the line linking it to its label. Took note of the tools's measure of "number of pixels from picture edge to mouse cursor" at both ends of the line. They are: 144, 113 140, 121 Horizontal and vertical displacements are respectively 4 and 8 pixels. The lenght of that line, following the Theorem of Pitagoras, is the square root of the sum of the squares of the horizontal and vertical displacements. That's 8.944 pixels. If that corresponds to Billbo's shoulder length of 41cm, that means a pixel of your Diagram of a Dragon is 4.584cm long. Taking just the horizontal displacement for an approximation, the tip of the head starts at 70 pixels, the curve of the tail at its rightmost is at 627 pixels, and the tip of the tail is at 513 pixels. So the whole dragon is approximately (627-70)+(627-513) = 671 pixels long. Multiplying the length of the dragon in pixels by the length of one pixel in centimeters, we get 3075.8 cm. So about 31 meters long, from head to extended tail. [Answer] The only animals which could swallow an adult human whole without tearing their bodies apart first are giant constrictor snakes, which squeeze their prey to death first before swallowing, to avoid the scenario in the question where the prey could damage their digestive system. And large adult male sperm whales. If a human is oriented correctly, it can be swallowed whole and thus possibly alive by a large adult male sperm whale. I am not certain about the ability of smaller sperm whales. However the story about James Bartley being swallowed alive by a sperm whale is fictional. [https://www.australiangeographic.com.au/topics/history-culture/2017/03/did-a-19th-century-sailor-get-swallowed-by-a-sperm-whale-and-survive/#:~:text=Historians%20have%20since%20concluded%20that,stomach%20of%20a%20sperm%20whale.](https://www.australiangeographic.com.au/topics/history-culture/2017/03/did-a-19th-century-sailor-get-swallowed-by-a-sperm-whale-and-survive/#:%7E:text=Historians%20have%20since%20concluded%20that,stomach%20of%20a%20sperm%20whale.) <https://en.wikipedia.org/wiki/James_Bartley> <https://www.snopes.com/fact-check/fisherman-survived-inside-whale-for-three-days/> However, it should be possible for a large adult male sperm whale to swallow a man whole, and thus alive if they are live at the time. In one scientific book a list of the normal and unusual contents found in the stomachs of sperm whales included a human cadaver. And the word cadaver indicates to me that it was someone wrapped up in a sack, weighted, and buried at sea to be later swallowed by the whale instead of someone alive when swallowed. I once read a mention of a fight between whalers and the legendary great white whale Mocha Dick, a main inspiration for you-know-who, where Mocha Dick allegedly swallowed two whalers who fell into the water. I don't know if Mocha Dick actually swallowed them or they just fell into the water near his mouth and sank due to the weight of their clothing, and the witnesses imagined Mocha Dick swallowing them. I once read of another incident where a harpooned sperm whale smashed a whale boat possibly by biting it in half, and then submerged carrying a man in its mouth. The other whalers must have though he would certainly drown or be eaten. But the whale came back up, tossed the living man onto floating wreckage, and dove again. So if you were being attacked by a pack of wild animals would you rescue one of them which got injured? Maybe the whale didn't know that the human was one of its attackers. Suppose you are walking through bushes when you feel a sudden stabbing pain in your back and you run away without looking back to see what's attacking you. Suppose you run into a bush and knock a bird's nest with a baby bird onto the ground, and stop to pick up the nest and bird and put them back in the bush, and then resume running for your life. Wouldn't that be a very kind and considerate thing for you to do? And wasn't returning a man to the surface be a very kind and considerate thing for the whale to do while being attacked? Anyway, I once read of a man who crawled down the throat of a dead large adult male sperm whale to reach the stomach. I think he would have been very stupid if he didn't have a rope tied to him and people ready to pull him out if he got stuck. Anyway his example seems to show that the throat of a large adult male sperm whale could be wide enough for the body of a man to pass through if in the correct orientation. And I once read of a dead sperm whale tourist attraction where people could walk down the throat and into the stomach. Although I suspect that the operators of the attraction excavated to make the throat and stomach larger than when the whale was alive. Anyway whale scientists who have dissected sperm whales of various sizes should have measured the diameters of the throats and stomachs of those whales and should have a good idea of the relationship between overall length and throat diameter. This site claims it is very, very improbable for a living person to be swallowed alive by a sperm whale. > > And some experts claim that it may theoretically be possible for a sperm whale to swallow a person whole, though there are two problems with this. One is that the sperm whale’s dagger-like teeth would likely kill the prey first, in which case you’d be long dead before suffocating in the whale’s several stomachs. But this point is rendered mostly null, as sperm whales only feed deep beneath the surface of the water and would never view humans as prey. So any accidental swallowing would have to derive from a rather bizarre sequence of events. > > > <http://www.todayifoundout.com/index.php/2020/07/so-how-do-animals-swallowed-alive-actually-die-and-do-any-animals-ever-get-out-alive-after/> I note that Sperm whale teeth are actually rather blunt, not dagger like, so how much they hurt a person would depend on how hard the whale bit down. If the whale bit with full force it would be like having a drawbridge fall on you. I note that healthy sperm whales have been found which were toothless, and others with malformed lower jaws which couldn't close on the upper jaw, and even one without a lower jaw. Apparently such whales feed by sucking in their prey and often don't bite on the prey. It does offer some helpful stories about how some animals do manage to survive being swallowed alive. And Wikipedia says: > > While the veracity of the story is in question, it is physically possible for a sperm whale to swallow a human whole, as they are known to swallow giant squid whole.[11] However, such a person would be crushed, drowned or suffocated in the whale's stomach.[editorializing][citation needed] Like ruminants, the sperm whale has a four-chambered stomach. The first secretes no gastric juices and has very thick muscular walls to crush the food (since whales cannot chew) and resist the claw and sucker attacks of swallowed squid. The second chamber is larger and is where digestion takes place.[12] > > > <https://en.wikipedia.org/wiki/James_Bartley> So a large adult male sperm whale would be about the minimum size creature which could have a throat wide enough for an adult human to crawl down to reach the stomach and attack the stomach. Could land animals that heavy exist? > > The sperm whale is the largest toothed whale, with adult males measuring up to 20.7 metres (68 ft) long and weighing up to 80 tonnes (79 long tons; 88 short tons).[36][37][38] By contrast, the second largest toothed whale (Baird's beaked whale) measures 12.8 metres (42 ft) and weighs up to 14 tonnes (15 short tons).[39] > > > <https://en.wikipedia.org/wiki/Sperm_whale#External_appearance> Though much larger ones have been reported. Anyway, the most massive sauropod dinosaurs had weights estimated to be even heavier than the most massive sperm whale ever weighed by humans. Their necks are slender compared to their bodies, but some of them could have throats several feet wide. Thus animals with enough mass to possibly have throats wide enough to swallow humans can walk on land on a planet with 1 *g* surface gravity and an atmosphere similar to that of present day Earth. But of course no carnivorous land animal ever had more than a fraction of that size. Though their throats should have been narrower, they do show that creatures with the weight of large adult male sperm whales, and thus possibly having throats as wide as sperm whales, could walk on land on a planet with a surface gravity of 1 *g* and an Earth like atmosphere. And just for fun, here is a link to a image from a Prince Valiant comic strip in the 1930s where he fights a giant sea crocodile. <http://aprincenamedvaliant.blogspot.com/2011/11/sir-gawain.html> I think in the 198s there was rather similar plot with a giant lizard crawling toward Camelot. And in about 1960 or so I have a dim memory of a full page panel where a knight on foot with a sword faces a giant crocodile with the mouth opened wide enough it looked like the knight could have stepped inside the mouth. And that reminds of an illustrated children's book from decades ago where a Chinese boy confronts a Chinese dragon that looks a lot like a crocodilian. I remember one illustration where the dragon's mouth is propped open with a pole and the boy is in the mouth walking toward the throat. As I remember, he goes inside the dragon to either kill it or help it. [Answer] The dragon needs to be the size of a sperm whale. Reference: [Swallowed by a Whale](https://www.ycaol.com/swallowed.htm) Fair Use Quotation: > > Late that night, working by lantern-light, the tired crewmen removed the stomach of the whale and slowly winched it to the deck for flensing. They were startled to notice movement inside the large sack, movement that looked like something living and breathing. The captain called the ship's doctor who made an incision in the tough flesh. And out slid the doubled up missing sailor, James Bartley, as if he were suffering from severe stomach cramps. He was alive, but unconscious. > > > > > The doctor ordered Bartley drenched with sea water, a treatment which restored his consciousness but not his reason, for he babbled incoherently. > > > > > Confined to a cabin for several weeks and bound so he could not injure himself in his wild flounderings, Bartley gradually regained his senses. Within a month he was able to relate what had happened to him in his terrifying experience. > > > > > Bartley said that as he was cast into the water from the long boat he saw a tremendous mouth open over him and he screamed as he was engulfed by it. He then felt sharp stabbing pains as he was swept across the teeth and then slid feet first down a slimy tube that carried him to the whale's stomach. He could breath, but the hot, fetid odor soon rendered him unconscious and the last thing he remembers was kicking as hard as he could at the soft, yielding stomach. Finally, he lapsed into unconsciousness until he again came to his senses almost a month later. > > > There was also a documented incident last year where lobster diver Michael Packard was swallowed alive by a humpback whale and lived to tell the tale. However, he was only in the mouth of the whale, not its stomach. Reference: [Cape Cod Times](https://www.capecodtimes.com/story/news/2021/06/11/humpback-whale-catches-michael-packard-lobster-driver-mouth-proviencetown-cape-cod/7653838002/) ]
[Question] [ I'm imagining a world populated with a species of intelligent, social, and "modern" (in terms of technology) humanoids. For the purposes of this question, they and their world can be near identical to us, except they are obligate carnivores. I think this may be a mildly controversial point, but it is my understanding that the amount of food used to grow livestock could feed a much larger population of humans than the livestock themselves will feed (see [here](http://news.cornell.edu/stories/1997/08/us-could-feed-800-million-people-grain-livestock-eat) and [here](https://foodprint.org/issues/animal-feed/?cid=260) for two simple examples). Similarly, top carnivores are frequently the least common animals in the food chain, as a simple consequence of the fact that there needs to be more of everything else for them to find enough to eat (if you pardon the gross oversimplification). This leads me to believe that, all else being equal, a species of technological carnivores would have more trouble maintaining as large of a population as we do on the same world, due to the logistics of acquiring sufficient food. However, I'm not actually sure if this is true, nor am I sure what the main limiting factors would be (increased land use for food, increased environmental destruction, increased transportation needs etc...) and if they limiting factors might cause more short-term or long-term problems (aka New York city is simply no longer possible for logistic reasons, or modern cities are possible but increased environmental destruction causes more sever global warming). Of course, another possibility is that this won't be an issue at all. To summarize though: 1. Would being an obligate carnivore make it harder for a technological society to enjoy the same sustained population growth that we have had? 2. If not, what are likely to be the primary limiting factors? [Answer] Food logistics is still a primarily limiting factor on human population growth now; I see no reason for it not to be with a carnivorous species as well. I think the real question you're asking is whether a purely carnivorous species will be limited *more* or *less* than we are, and the answer can only be **more**, because you're in essence limiting the options of what a species can eat and that kind of specialisation is always punished by evolution on earth as it changes. Human success is at least in part based on the fact that we can eat almost anything. Vegetables of course, fruit, other animals, and some foods that would kill other animals. Have you ever seen those posters up in your local vet about all the foods you **can't** feed your dog, and why? Dogs, which as a species are pretty flexible in what they can eat, can only eat a small subset of what we can. In practice this means that humans can grow as a species because wherever they go, they can find something they can eat. In places where they can only find things they can't eat (like grassland prairies), there are plenty of animals that we've domesticated that can eat the grass, and then we eat the animals. So, we still make use of the local resources. Finally, humans can now grow in even bigger numbers because of distribution technologies. We can get massive amounts of food into our cities every day, offsetting the fact that those cities don't produce much of their own food. In point of fact, our society is capable of growing to its current size because we need so much smaller a percentage of that population to actually produce the food that we all eat. Moving on to your carnivores, if they have the same level of technology, then you probably only need the same small percentage of it to produce food for the others, so in that respect the limiting factor is the technology, and is the same as what we currently face. The bigger problem is the fact that you're limiting yourself to a specific food type, meaning that you can only move to places and areas where that food type can be supported. Many graziers actually do plant crops; they just plant crops of tall grasses for their cattle, sheep or otherwise. They do this so that they can support a larger population of meat stock on their lands. I'd expect that your carnivores would do the same thing, but the food your meat animals eat might not grow everywhere, meaning that you have a limitation in the amount of food you can produce. For us it's not a problem because if the land doesn't support pasture cropping, we just grow something else on the land; something else we can eat. Your species is going to find that difficult. So yes, your food supply will ultimately be the limiting factor, because it's **our** limiting factor as well. Also, because you're limiting the food *types* that can be consumed, your growth is likely to be smaller as well simply because as the world changes its harder to support specialised food supplies. As such, your technological species had better be good at adapting. [Answer] # Doubtful Assuming this species did not just appear overnight and that they were able to reach modern levels of technology. I don't think that logistics of food will limit a population size. With modern logistics I can get my "product" shipped to my door overnight from a warehouse in a different city. Might not be the exact same with food but we're getting pretty darn close. Logistics are getting better and better with the inclusion of modern technology (computers, AI, robots, multitude of transportation options). Creation of food might be a limiting factor (still doubtful considering economic forces would push the market to keep up with demand), but being able to move it from point of creation to point of consumption with modern technology would not be an issue. We have refrigeration and preservatives (might not be the healthiest thing but it does extend the shell life off food). Keeping food from spoiling would also not be an issue in this modern era. Keeping things as parallel to todays world as possible one of the biggest differences I would see would be that the average family would spend a larger % on food. If logistics include the creation of food then imagine all the research done for plant GMOs (genetically modified organisms) now being redirected towards animal GMOs. Might have more moral / ethical questions but I am very confident that the volume of food created would be able to keep up with population growth. [Answer] I suppose in some ways, yes, but there are really three parts to consider here: technology, planet size, and livestock size. # Technology Exactly how technologically advanced is this species? Is it the same as humans? It is entirely possible the species may have ways of producing synthetic meat, or using cloning technologies to produce meat. This is perhaps even a point to build culture around, with synthetic meat being considered a poor persons food, and natural meat for richer people. You know, the kind of thing white suburban moms would brag about at the PTA meeting: "AT LEAST I DON'T FEED MY CHILD FAKE MEAT KAREN!". You get the idea. # Planet Size How large is the planet the species is inhabiting, especially compared to current population size and required living space? Perhaps the species has indoor farms in skyscrapers, producing food right in the cities where it is needed. Perhaps there is something similar to the Japanese roof gardens, where people in cities have areas on top of buildings where they can grow a communal garden. # Livestock Size How big are the most common livestock, what do they eat, and how fast do they reach maturity? All of these are things to consider in your determination of whether or not the society can produce enough food # Conclusion There are many factors in deciding how food would limit population growth, but ultimately, any society will eventually be limited by it's food production capabilities. [Answer] A strictly [carnivorous](https://en.wikipedia.org/wiki/Carnivore) humanoid species' [population size](https://en.wikipedia.org/wiki/Population_size) would be limited by the amount of available [arable land](https://en.wikipedia.org/wiki/Arable_land) in the same way that an [omnivourus](https://en.wikipedia.org/wiki/Omnivore) species would be. In order to [farm animals like cows or goats](https://en.wikipedia.org/wiki/Meat_industry) you will need meadows/pastures for them to [graze in](https://en.wikipedia.org/wiki/Grazing). If this fictional humanoid species lived on a [relatively small rocky island like Japan](https://en.wikipedia.org/wiki/Agriculture,_forestry,_and_fishing_in_Japan#Land_shortage) the amount of farm land might be extremely limited. You might be able to mitigate this somewhat by [factory farming](https://en.wikipedia.org/wiki/Intensive_animal_farming) like is done with pigs, but at the end of the day every area has its [carrying capacity](https://en.wikipedia.org/wiki/Carrying_capacity). If this fictional humanoid species had advanced enough technology then [cultured meat](https://en.wikipedia.org/wiki/Cultured_meat) might be a viable alternative. [Answer] **Indirectly limited** Thomas Malthus had the highest misfortune of describing existing trend exactly in moment when it finally started loosing its relevance. Humans are at latest from the green revolution ('50s-'60s) no longer realistically constrained by food production in any way. If somewhere is a famine, it is not caused by technological or environmental inability of producing food, but political issues (read: Mao's Great Leap Forward as last big example). Right now we are as fussy as we want. Beef? Salmon? Avocado? Ecological food? No big deal. So if such specie reached the same technological threshold, sooner or later they would be fine. Nevertheless, you have a very good argument why their population should be much lower than humans - all their history, until somewhere around XIXth century equivalent they were drastically restrained by food production. Low food -> low population -> less scientists -> slower growth. If they made it anyway, then they are fine. However if at their year 1900 equivalent their global population was 500 mln, then right now their population may be reaching 3 billion. Not because they are hampered by their diet right now, but because their population haven't grew so much from times when it mattered. Moreover as result of historical legacy their population could be a bit more dispersed. There are plenty of inhospitable lands (or sea shores in sub-polar regions which are rich in fish) that may be considered by a carnivore as quite tempting. [Answer] ## Land To produce meat capable of providing 1 kilocalorie of energy one needs to feed the chickens/pigs/cattle anywhere between 3 and 20 kilocalories of vegetable food, for a [conversion ratio](https://en.wikipedia.org/wiki/Feed_conversion_ratio) from 30% (for broiler chicken) to 5% (for luxury beef). Thus, in a first order appoximation one can say that to reach the same population as us omnivores, the obligate carnivores would require anywhere between 3 and 20 times more land dedicated to agriculture. Going into more details is complicated, because while chicken and pigs eat more or less stuff which *we* could also eat, ruminants (and horses) do not *have to* compete with us -- they can eat grasses, which humans cannot digest. In practice, cattle grown for meat are fed a lot of grain, which of course comes into competition with human food. On the other hand, we use a quite lot of grain to make dubious products such as ethanol (to drink or to burn)... The problem is of course that there is no such undeveloped land available on Earth; with very advanced technology we might be able to increase the area under cultivation by, maybe, 50%, but increasing it by a factor of 3 or 4 or 5 is out of the question. The sad conclusion is that at best the man-sized obligate carnivores cannot reach a population level higher than one quarter to one third of the present human population. However, this is not the saddest conclusion. The *really sad* problem is that I see no plausible way for them to sustain a pre-modern civilization. With pre-modern agriculture primary productivity was low, and feed conversion ratios were dismal. Consider that during the antiquity and the middle ages, the average human was lucky to get 5% of their energy from meat; the other 95% came from vegetable sources, mostly cereals and pulses. But it may well be that this can be handwaved somehow. ## Logistics Meat is much more energy dense than vegetables, especially in terms of volume. So there is no reason to believe that the logistics of bringing all the food into the cities in the form of meat will be more complicated than bringing it in the form of vegetables; if anything, the logistics will be simpler. [Answer] **Will food logistics limit the population of a civilization of exclusive carnivores with modern technology?** If you mean transportation and storage, maybe. If you mean, the geopolitical system of food production, very likely. **Would being an exclusive carnivore make it harder for a technological society to enjoy the same sustained population growth that we have had?** Yes, indeed. The agricultural revolution was key for population growth, and hence, ancient technology. **If not, what are likely to be the primary limiting factors?** In decreasing order: climate change/energy sources, peasant labor, drinking water and arable land. **Explanation** This is a complex question, so I'll try to explain some points and then come back to the answers. According to Systems Ecology, the limiting factor for the population growth of any species is always the amount of energy it can derive from its environment in a useful way. For most species, this means that the food consumed delivers more energy to the body than the energy invested in basal metabolism and other activities, including of course, those activities that are meant to obtain food (i.e. grazing, hunting and gathering). For example, if gazelles develop a way to run faster, the cheetah population would narrow to the fastest cheetahs. Then the latter species might either evolve into some sort of faster supercheetahs (who need and get more energy from their environment) or dissapear altogether due to famine, sickness, poor genetic diversity, etc. but that is a different story. For those species that hunt in group, the rule applies for the whole group: those packs of wolves that are able to catch faster gazelles would thrive, but the species might be endangered for the same reasons pointed out in the case of cheetahs. For those species that are able to produce their food, i.e. transform their environment in order to catch or grow their food, the energy rule holds as well but it gets more interesting. Bees, ants, termites, spiders, beavers, among others, modify their environment to obtain and store their food, so the amount of energy invested in running the production of food must be lower than the amount of energy delivered by the food produced. The energy needed to maintain the glands and synthetize the complex molecules that form the thread of a spiderweb must come for the preys that the web catches. When it comes to humans, things get even more complex because our species has been able to use exosomatic energy (energy outside the human body) to produce food. In other words, the energy invested in producing, storing and transporting food does not necessarily comes from the energy delivered to the human body through food digestion. Agricultural tools, beasts of burden, natural and chemical fertilizers, machinery, gasoline, etc. are used in the production of food, but the energy required to produce them comes mostly from fossil fuels, biofuels (bioethanol mainly) and primary electricity (hydro, solar, wind, nuclear, biomass, etc.). These exosomatic sources allow us to grow food in deserts, mountains, and other places where it was impossible to produce it a hundred years ago. If you plot the world population and the world production of fossil fuels over time, you will see that both lines start growing roughly at the same time. Land, water, soil and the "usual" limiting factors are not an obstacle to our food system AS OF TODAY. Each of these factors can be supplied, enhanced or substituted using the exosomatic energy sources mentioned above. In fact, the current food system produces more food than required by the world population (according to FAO), so edible crops are used for other purposes. There so much corn, for example, that it is used to make ethanol for cars, to feed livestock and to sweeten all kinds of things (that's why you can find high-fructose corn syrup in your favorite soft drink). Since the system is based on fossil fuels, it is clearly unsustainable in the long run but that is a different story. Feeding humanoid carnivores is a bit harder than feeding humans. However, while it seems doubtful that a carnivore population of 7.2 humanoids would survive under the current energy available to us, it is equally doubtful that they would grow at the same rate that omnivore *Homo sapiens* did because the amount of energy and biomass required to grow carnivore food is larger. In a trophic pyramid, **only ten percent of the energy contained in one level can be transferred to the next one**. Since life is basically made of the same molecules (carbohydrates, proteins, etc), this number is also an approximation of biomass transfer. In other words, you need 100 lb of grass to feed 10 lb of herbivores (even if it's 1 lb of insects), and then feed 1 lb of carnivores. For carnivores, agriculture would only be the step in the food system. In fact, carnivore humanoids might never had developed such a labor intensive practice in the first place! Why take all that time and energy in a system full with weather uncertainties when you can go around hunting game happily? In fact, hunter-gatherer communities were healthier than agricultural societies, not to mention absence of slavery, plagues, wars and other niceties that characterized agricultural empires. On the other hand, hunting carnivore humanoids might go extinct after they hunt down every last game available. In fact, humans are held responsible for the extinction of megafauna in all continents except Africa, where elephants, rhinos and hippos evolved together with sapiens, so they "know" that our weak appearance is deceiving and that sapiens are not to be trusted. Assuming our humanoids did develop agriculture as a desperate means to "grow" their own chickens or something, you would have a though problem feeding carnivore slaves and peasants. Anyways, let's assume peasant labor was fed on a mix of dry insects, blood and bones for some time until some ancient civilization found coal (energy resource) and built some steam engine (technology) that they could apply to agriculture (note we are talking here about two major processes in human history: agricultural and industrial revolution). Even in that case, the rate of growth of the population would be lower because these humanoids would still be entirely on the third level of the trophic pyramid, rather than partly on the second level as our agricultural ancestors were. ]
[Question] [ Dear Royal Council Member, It has come to our attention that the natural sources of magic are starting to dwindle, and as a result we will start to phase out our reliance on magic. Before long, magic will be outlawed completely to try and preserve whatever magic is left. We will be pushing the development of steam-based technologies. During the shift, any magic that is deemed necessary will be permitted, to expedite the progress. You have therefore been summoned to the court, to help give some insight into what repercussions we should prepare for in the coming years, as we push this change to society. With kindness, Queen Mary the Everliving, Ruler of the Human Empire --- # What happens when you force out an existing technology, that remains available, but illegal, and replace it with a different one? I'm hoping to get some interesting ideas about what to expect from a societal perspective from the changes. Some people will barely be affected and some people will be more affected, but I'm not sure how. Will this start an arms race between other nations? How will magical societies, like entertainers, magical merchants and religious sects adapt? Would secret magical sects start to form? I'm currently looking at what to expect in a long period like 400-500 years. ### Society/Setting This is set in a **generic medieval fantasy** setting. Although **magic isn't rare**, it's also not something the common people rely on. They're **still using conventional medieval tools** to do their jobs. Higher class people are much more used to magic. ### Magical Technology Magic is used in a wide variety of situations, ranging from combat to entertainment and quality of life. In combat, it is manifested as spells that make a small group a very maneuverable siege engine. Training a group of casters for this purpose is time-consuming and expensive, so conventional siege engines are still used. They are unparalleled in their utility in overcoming obstacles, easily conjuring temporary bridges or removing dangers. Magic will still be a part of army combat, so there won't be many changes here. In entertainment, magic is primarily used for the illusional effects, aiding in telling tales and acting out plays. There are also specific spellcasting arenas for magic duels. In everyday life, magic is used primarily by the higher classes, as a utility to help out with things like cleanup, keeping things fresh or even hiding the scent of the medieval streets. ### Conventional Technology Metallurgists have access to **metals that are both more durable and stronger than conventional metals**, but iron and steel are still the most commonly used metals. There is another land that offers **crude oil** in trade, although its uses haven't been explored much yet. Alchemists also know how to make **gunpowder** and crude bombs, but due to their unstable nature and the fact that a trained spellcaster can cast a fireball spell much safer, they haven't been explored much either. ### Political There are nations of Kentaurs, Elves, Gnomes, Humans, Dwarfs and some less pleasant races. Most nations agree that it appears something is wrong, but there's one nation of magical beings that are **unwilling to follow with the changes, and will openly continue to rely on their magical powers**. Aside from The Big Bad Guys Nation, there is currently **mostly peace** between the rest of the nations, and almost all have some kinds of **trading agreements** with each other, but everyone also still keeps **active armies**. [Answer] The problem with this scenario is that you can't force everyone to cooperate. It's not in their best interest. Let's imagine for a moment that all your top advisers, which include some very powerful mages, agree that "natural sources of magic are starting to dwindle". And they also agree that some steps must be taken to preserve this most valuable of resources. ### 1) Availability of services Your average every day person doesn't use magic. They might, however, pay a mage for the occasional healing, or help in solving an issue. These services are about to become unavailable forever, and that won't go over well! Where there' a healthy demand, a supply is sure to follow. If you cut people off from a whole gamut of services they feel they strongly about, then what's most likely to happen is that a black market will spring up, offering those services for very steep prices. (think along the lines of the USA's Prohibition). More importantly, however, magic was most likely used quite extensively in government projects and military applications: * Oh, the King wants to know what's happening on the frontier? Let's communicate with the local commander via magical means, or teleport some official over there. * We need a sturdy bridge built in a hurry, for our army to cross this ravine? Magic to the rescue! * A large group of orcs is about to overcome your garrison? A handy fireball will save the day. Suddenly removing these elements from society will severely damage your government, and erode your power. Which brings me to my next point: ### 2) How will you convince others to give up magic? You listed quite a few races which coexist on your world, and, presumably, there's more than one human kingdom around as well. You may choose to limit your use of magic in order to preserve it for future generations, but who's going to get all the other kingdoms and races to agree? Worse, even if they verbally agree to cut back on magic use, how can you ensure that they will ***actually do so***? > > I'd like to draw a parallel to the many environmental agreements which our leaders have signed: It's not much use if you convert your entire industry to be "green", incurring high costs in the process, and damaging your economy, if your neighbor will continue to dump toxic waste in the water your countries share. > > > ### 3) Resistance to change Let's face it, magic is awesome, and asking everyone to give it up is a bit of a tall order. Luxuries which the elites are accustomed to are going to dry up. Some of these powerful lords, whose lives have maybe been significantly lengthened, or otherwise enhanced by magic, will resist your efforts to cut them off from it. Most likely with violence. ### 4) Can you reach a consensus? Even among mages and nobles there is going to be a debate whether magic is really running out, and at what rate. Humans are not well known for our ability to plan for the far future. Think fossil fuels, deforestation, and climate change. You could tell everyone that oil is running out, and that in the interest of future generations we should all give up our personal vehicles, implement extensive public transportation networks, and replace any remaining combustion engines with electric ones. How many nations do you think would pay lip service to your noble goals, and how many would try and implement it? Magic is in a similar category. Many mages will see this as an attempt to limit their influence and power. Many nobles will see it as an attempt to monopolize the use of magic for your own use (the government's). Other races may see this as an attempt to weaken them economically and militarily. There's little chance of a consensus here. ### 5) Conclusion What you're proposing has enormous military, economic, and social ramifications. It will most likely lead to civil unrest, and war. You should probably start by convincing some very powerful mages that it's in their interest to help you restrict the use of magic (promise them privileges, access to magic sources, positions of power, etc.). Have them form a "Society for the Preservation of Magic", and start pumping out propaganda about the dangers of wide spread magic use, etc. (get the population to move away from it). In parallel, have these powerful mages start shutting down the projects and practices of weaker mages, slowly cutting them off from magic sources under various pretexts such as "unethical use of magic". These lesser mages may need to be bullied into submission, jailed, or maybe even executed. You will also need to meet with other heads of state, and try to get them on board with your plan. Your coalition will have to bully other kingdoms and races into adopting your practices, and you will most likely have to go to war with those who refuse to adopt them. Of course you will also need to start training up engineers, doctors, etc. to replace the magical services you're cutting off. Some institutions will need to come into being, such as the Guild of Engineers, Guild of Doctors, etc. Over a decade or two you should be able to achieve your goals of making magic a very exclusive, and hard to access resource. [Answer] # Peak Magic > > [*Any sufficiently advanced technology is indistinguishable from magic.*](https://en.wikipedia.org/wiki/Clarke%27s_three_laws) > — Arthur C. Clarke > > > If magic is a measurable resource, and its uses are something that you can learn and exploit, then what you have is not magic; it is a natural resource being used to affect and/or power technology. Sure, you can name it "magic" if you like, but for all practical intents and purposes, it is fuel that powers technology. What happens when your technology relies on a resource and that resource is running scarce? Well... no-one knows for sure because we have never experienced that scenario for real. The closest we can get is [Hubbert's Peak Theory](https://en.wikipedia.org/wiki/Hubbert_peak_theory). This is your first question on Worldbuilding and due to rather arbitrary reasons I will grant you a little bit of leeway, and not vote to close, since I could give you a sort of answer. But do know that your question here is extremely broad; the number of possible outcomes is vast. Therefore I am giving you this broad answer: **Apply Hubbert's Peak Theory to your world, and try to create scenarios from that.** [Answer] Building on one aspect of [AndreiROM’s comprehensive answer](//worldbuilding.stackexchange.com/q/72591/20215#72602), I am reminded of [*The Space Eater* by David Langford](http://www.infinityplus.co.uk/nonfiction/spaceeater.htm), in which 1. Mankind creates some colonies in other star systems, and then loses contact with them. 2. Earth scientists discover a field of technology called “Anomalous Physics,” which features such staples of sci-fi as wormholes, matter transmission and matter conversion. 3. Earth scientists discover that the use of Anomalous Physics (beyond certain constraints) damages the fabric of the universe. 4. Earth military scientists discover that one of the colonies is using Anomalous Physics recklessly, apparently not yet having discovered the risks. So the military sends emissaries to the colony to get them to stop.  Using a classic iron-fist-in-a-velvet-glove approach, the emissaries start with diplomatic persuasion, but they have a Plan B: a weapon that will destroy the colony if they don’t cooperate (which, of course, they don’t). In real life, there is a similar situation: the politics of greenhouse gas emissions.  As far as I know, that’s still being addressed by peaceful negotiations.  But, when snow becomes a thing of the past, temperatures of 100 °F become commonplace, and coastal cities start being submerged by rising sea levels, somebody might start thinking that the third-world countries that are still burning dirty coal really need to have nuclear power delivered to them.  By missile. So, yeah, the nations that agree to phase out the use of magic are probably going to come into severe conflict with the nation(s) that don’t. [Answer] Here is my main question to you: Is Magic a local or global resource? **If it is local**, the problem will solve itself; mostly. If a nation refuses to limit its use, it will burn though the magic available in its land (like over farming does). Then they would have to be mobile. They would have to conquer the lands around them and move into those. The defense against that is to use magic to defend those lands heavily enough that you burn them out and make them useless to the would be conquerors. **If magic is global,** it is in the best interest of every group to use as much magic as possible to achieve as many gains as they can before it is gone. Yes, magic will burn out faster but if your people are in a better position for a "post magic" age, then you won. Everyone would have to get together to defeat the "cheaters" while, themselves trying to not get caught cheating. In this situation, I would use as much magic as I could to secure the resources and manpower my people needed to survive. **On another note, technology requires a cultural change.** You need to go from a knowledge hoarder culture to a knowledge spreading culture. Everyone needs to know the basics of tech in order to grow it quickly. The problem with that is that there will generally be guilds or other groups whose power base comes from restricting knowledge from the general public. Those power bases will oppose any spreading of knowledge/power. [Answer] Worst case scenario: war. Those whose wealth or power comes from magic would lose their wealth and power if magic suddenly became illegal. Depending on how many people these are and how powerful their place in society is, this could lead to civil war. Plus remember people tend to dislike change and be suspicious of new technology when it comes out. > > How will magical societies, like entertainers, magical merchants and religious sects adapt? > > > That depends on how reliant they are on magic. You can definitely expect some kind of push back. Riots, sabotage. And in extreme cases, war or terrorism. [Answer] So you have a measurable amount of magic. Let's call it "mana". So the main problem is - how to figure out the mechanical way of achieving magic outcome. For example: flying brooms and carpets are common way of personal travel. Try to swap it for something technological. You either conclude that is not possible or you use magic to explain how the oil/steam powered machine can do the same thing. Or how to put it different way (and I know it's not popular opinion) Steampunk is just magic but in Brunel tophat. ]
[Question] [ On Earth we don't really notice many effects of the Earth spinning, apart from the day-night cycle. It took a long time for people of Earth to realise that it even was spinning, but there are measurable effects (differences in gravity, [the Coriolis effect](https://en.wikipedia.org/wiki/Coriolis_force)). Would it be more obvious if the Earth spun 2 times faster? 10 times faster? 100 times faster? 1000 times faster? The Sun would appear to move faster, but what else would we notice? Could life survive on a planet spinning that fast or would we all be flung into space? I suspect at some point the Earth would break apart. [Answer] [There's an excellent answer on Quora about this.](https://www.quora.com/What-would-happen-if-earths-rotation-speed-increases) > > 1. The Earth would become an even more imperfect sphere and this would reduce the acceleration due to gravity; it would decrease at the equator and increase at the poles. Also, the days would shorten. > 2. Since the effect of gravity has deceased near the equator, we would observe tides much higher than usual in these areas, much more land would go underwater during high tides. I assume Venice would cease to remain habitable. > 3. [The precession of the Earth’s axis would change](https://en.wikipedia.org/wiki/Axial_precession#Cause). As the Earth becomes an even more Oblate Spheroid, the gravitational differences (of the Sun on Earth) would be larger on different parts of the Earth, this would make the axis precess even faster. The current cycle is 26,000 years long for one complete precession, this would shorten depending on the increase in rotational velocity. > 4. North Star would change faster. Currently the North Star is Polaris which is set to be replaced by Deneb in 8,000 years. Due to the above reasons, it would occur faster and astronomical charts may cease to be relevant. > 5. It is also possible that the axial tilt of the Earth would increase. This would mean that winters would be colder and summers would be hotter. > 6. Since the Earth now rotates faster and the Coriolis effect depends on the rotation of the Earth, the impact of [Coriolis effect](https://en.wikipedia.org/wiki/Coriolis_force) would increase and we would experience faster wind speeds. > 7. This would be a boon for [geostationary satellites](https://en.wikipedia.org/wiki/Geostationary_orbit) as the operational altitude would reduce due to Earth’s increased rotational velocity. > 8. Since the [Sidereal day (Sidereal time)](https://en.wikipedia.org/wiki/Sidereal_time#Sidereal_time_and_solar_time) would now be shorter, we would have to redefine our present units of time. > 9. Since the Coriolis Effect would alter the wind speeds, and the rotational velocity of Earth has increased, the travel time of aeroplanes would change. [Watch: If Earth is spinning to the east, why isn't it faster to fly west?](http://www.sciencealert.com/watch-if-earth-is-spinning-to-the-east-why-isn-t-it-faster-to-fly-west) > > > Speeding up significantly could have effects on the Earth itself, to the point of nonexistence ([See HDE's excellent answer for details!](https://worldbuilding.stackexchange.com/a/64858/17568)). My answer tells what would happen on a sped up earth, so keep in mind going certain speeds may amplify certain parts of this answer. [Answer] # When will the planet break apart? A solid body will break up if the centrifugal force at a point is equal to the gravitational force. At Earth's equator, the equation becomes $$\frac{GM\_{\oplus}}{R\_e^2}=\omega^2R\_e$$ where $M\_{\oplus}$ is the mass of Earth, $R\_e$ is its equatorial radius, and $\omega$ is its angular speed. Rearranging and solving for $\omega$ gets $$\omega=\sqrt{\frac{GM\_{\oplus}}{R\_e^3}}$$ Assuming $R\_e\approx\bar{R}\_{\oplus}$, its mean radius, we have $$\omega=1.24\times10^{-3}\text{ rad s}^{-1}$$ Earth's current angular velocity is approximately $\omega=7.29\times10^{-5}\text{ rad s}^{-1}$. This is almost exactly 1/17th of Earth's breakup speed. Now, this assumes that $R\_e$ doesn't change with $\omega$ - which it does. In fact, [the equatorial bulge is](https://en.wikipedia.org/wiki/Equatorial_bulge#Mathematical_expression) $$R\_e=R\_p+\frac{5}{4}\frac{\omega^2\bar{R}\_{\oplus}^4}{GM\_{\oplus}}$$ At the original breakup speed, we have $$R\_e=6.356\times10^6+\frac{5}{4}\frac{(1.24\times10^{-3})^2(6.371\times10^6)^4}{6.673\times10^{-11}\times6\times10^{24}}=1.43\times10^{7}\text{ m}=2.24\bar{R}\_{\oplus}$$ This decreases the gravity by a factor of roughly 5, so the breakup speed is actually a bit lower. So at 100 or 1000 times its current rotation speed, Earth wouldn't be here. # The Coriolis force The maximum magnitude of the [Coriolis acceleration](https://en.wikipedia.org/wiki/Coriolis_force) is $$|\mathbf{a}\_c|\_{\text{max}}=2|\mathbf{\Omega}||\mathbf{v}|$$ where $\mathbf{\Omega}$ is the rotational velocity, and $\mathbf{v}$ is the velocity of a particular particle. This means that the force scales linearly with $|\mathbf{\Omega}|$, and thus can only be 17 times as large as it is right now, at a given point on Earth. We'd see [Rossby numbers](https://en.wikipedia.org/wiki/Rossby_number) (which characterize how much a system is affected by Coriolis forces) lower by no more than a factor of 17. As Anoplexian noted, this would lead to stronger winds and likely stronger hurricanes - although nothing catastrophic; an order of magnitude change here won't be devastating. I wouldn't be too concerned. # Daily life At 17 times the Earth's current rotation speed, each day would last about 45 minutes, and each night would last about 45 minutes. Even [at 12 hours per day-night cycle](https://worldbuilding.stackexchange.com/q/21521/627), you have to worry about humans getting the proper amount of deep sleep each cycle. 45 minutes is enough for a nice catnap, but not good sleep. I'd assume that creatures would either adapt to such a short sleep cycle, or sleep through several days and nights, and then spend several days and nights asleep. Whether or not either of these is feasible is something I'll have to look into; I'm not overly optimistic. [Answer] For us to "fly off the Earth", the centripetal force required to keep an orbit of the Earth's radius would have to be the same as the acceleration due to gravity. This would be of the order $\frac{v^2(m^2/s^2)}{6.4\times10^{6}(m)}=10(m/s^2)$ Meaning the velocity at the surface would be $8000(m/s)=\frac{2\pi r}{t}=\frac{4\times10^6(m)}{t}$ Meaning one day would have to last ~5000 seconds, or one hour 12 minutes. For this to happen, Earth would have to rotate about 17 times as fast as it does in reality. [Answer] For a fictional treatment of this, see Hal Clement's [*Mission of Gravity*](https://en.wikipedia.org/wiki/Mission_of_Gravity). In it, the planet Mesklin has a day approximately 18 minutes long, with a surface gravity of 3 G at the equator and 700 G at the poles. Much of the book involves the surface conditions and how the native species handles them. For example, they are instinctively terrified of even small heights, since at 700 G any fall is fatal. ]
[Question] [ How would the history of American colonization by Europeans differ, if the Native Americans were immune to the new diseases? From [Wikipedia](http://en.wikipedia.org/wiki/Native_Americans_in_the_United_States): > > Even before the European settlement of what is now the United States, Native Americans suffered high fatalities from contact with European diseases spread throughout the Americas by the Spanish to which they had yet not acquired immunity. Smallpox epidemics are thought to have caused the greatest loss of life for indigenous populations, although estimates of the pre-Columbian population of what today constitutes the U.S. vary significantly, from 1 million to 18 million. > > > Assume that the Native American population is at 18 million. [Answer] **The colonization would have happened much slower, later or not at all.** Not only would there still be 10 times as many Americans, they would still have their strongest and wisest leaders in place, a network of trade routes between tribes and finally all those fertile fields the settlers found lying fallow in our timeline would be claimed and farmed by the local tribes. Any settlers would face much more resistance at every turn. ## Much slower The most likely scenario is that the first boat loads of pilgrims get slaughtered or starve without land to farm, bringing that migration to a screeching halt. Then the Europeans switch to their standard tactics, the one that also helped them in Africa and Asia: **Divide and Conquer**. By initially trading with certain tribes and providing them with tactical advantages over enemy tribes, the Europeans ingratiate themselves and then barter for a small part of some defeated tribe's land. From there, they keep tipping the scales in inter-tribal wars and propping up their allies, escalating the inter-tribe wars, doing through bloodshed what the plague did in our timeline. ## Much later The first European settlers get kicked back into the ocean. Several attempts are made and violently repelled. The Native Americans tell their children and grandchildren stories of the white-as-death men that came from the sea and were pushed back by great heroes. After the Industrial Revolution in Europe, the next fleet to sail to the Americas is steam-powered, has cannons and a force of marines with rifles. The coastal tribes are forced to surrender as their villages explode around them and no arrow or spear can harm the ships. Some years of relative peace pass by as the Europeans set up their coal mining and industry, but after that they relentless drive west, conquering or exterminating any native tribes they encounter. Despite the obvious exposure to guns, swords and other metal items, it's highly unlikely that the Native Americans would catch up on their own. Pre-Columbian North America [did not have any knowledge](https://en.wikipedia.org/wiki/Metallurgy_in_pre-Columbian_America) of mining or the smelting and casting of metal, with the only known samples being worked copper that was probably found on the surface. South America did have these techniques, but they were exclusively used for decorations, mostly using gold. South Americans would probably have a decent chance of developing ironworking, given their better starting point and more extensive use of slave labor. The North American natives would have to overtake some huge cultural barriers, since proud hunters are not likely to accept having to break their backs digging for iron ore. The feudal system in Europe was a big advantage in that regard. Some strong tribes might enslave others to do their labor and set up a mine plus smelter, but large scale industry is very unlikely. For both North and South, the discovery of steel production would likely come too late to save them. ## Not at all In the third and least likely scenario, the Native Americans form a broad alliance of the eastern tribes after the first encounters. This prevents the Europeans from gaining any ground. They do however trade with the Europeans in coastal settlements and from this they acquire horses, metalworking skills and eventually the knowledge to produce guns. The eastern tribes then conquer the rest of the Americas and establish their own empire, rivaling those in Europe. The Aztecs would have been in a good position to trade their gold for Spanish steel if they had not been devastated by the smallpox, so perhaps they would have become the dominant empire in Middle and South America. [Answer] Having more people in place is not necessarily sufficient to prevent Europeans from colonizing the Americas. Most of the people, like today, would not be warriors or fighters of any description, so would not contribute materially to the defense of the land (although they would be able to support a much larger warrior class). If we look at India or China, we see densely populated lands which were overrun and colonized by Europeans because the Europeans could draw upon an entire cultural arsenal of ideas,tactics and enticements. They divided various kingdoms against each other, offered sophisticated trade goods and when things went south, could fight much larger "native" armies using superior European arms and tactics. And of course, the Europeans essentially controlled the seas, so they could come at the time and place of their own choosing, making organized defense that much harder for the natives. Native Americans would have a double disadvantage, since they would be facing all the sophisticated tools in the European arsenal, but would be starting their resistance from an essentially Neolithic culture. Even in the 1500's, this would be a huge mismatch in capabilities, and the native Americans who learned to use this to their advantage against enemy tribes would rapidly prosper under the rule of the Europeans. The best possible outcome would be the situation that Tecumseh tried to engineer with the war of 1812; allegiance with the British against the Americans in exchange for an independent Native American enclave (it is difficult to say a country or State, since Native American culture had not fully grasped the concepts of a "Nation State" as we understand it). Since there were many competing European nations looking to colonize the Americas, there is the potential for multiple native enclaves as various tribes and confederations throw in their lot with the Spanish, French, English, Dutch, Portuguese and other competing nations against the others. Of course, a lot will depend on who the eventual winners are.... [Answer] It seems pretty obvious that if the Indians had not lost millions to disease -- I've seen estimates of 90% of the population wiped out, I'm not sure what the scholarly consensus is, or how reliable any numbers are -- anyway it seems obvious that that would have put them in a much stronger position to resist European colonization. But exactly how would it play out? At one extreme, one could argue that it would have made little difference. Bear in mind that the reality was not a matter of "Europeans versus Indians". Both groups consisted of many competing nations. When Cortez conquered the Aztecs, a very important factor was that the real situation was not "a tiny band of Spaniards versus a huge empire", but rather, "a tiny band of Spaniards mobilizing many native nations who all had good reason to hate the Incas -- because the Incas regularly tortured, killed and enslaved them -- and leading them against the Incas". My point being: the actual history was a series of shifting alliances between various European nations and various Indian nations. If there had been more Indians, this would certainly have changed the dynamic, but as for most of history it was some Europeans and some Indians versus other Europeans and other Indians, maybe the Indians would have just killed each other and the end result would have been the same. At the opposite extreme, one can certainly imagine a scenario where the Indians all banded together to resist the Europeans and throw them off the continent. But that scenario is wildly improbable. It's like saying that Germany could have won World War 2 if only they could have convinced the French and British and Yugoslavians and Greeks to unite with them to fight the invading Americans. I think there may be some subtle racism here: the idea that of course Britain and France and Germany are distinct nations with distinct history and cultures, but that the Cherokee and the Navajo and Incas are all basically the same, there's really no difference between them, because they're all "just Indians", not "real" nations. Like I've heard many times that Malintzin, the Indian woman who served as a translator and guide to Cortez, was a "traitor to her own people" for helping the Spanish against her fellow Native Americans. Except ... she WAS siding with her own people. Her father had been assassinated by the Aztecs for refusing to submit to their power. Would you really say that she had some moral obligation to help the people who murdered her father, just because they were born on the same continent? That's like saying that in World War 2, the French were "traitors to their fellow Europeans" because they accepted aid from the United States and Canada to win their country back from the Germans. More realistically: There's both a moral, or perhaps public relations, question, and a raw power question. Regarding raw power, there's the obvious point that, despite all I've said above, the more Indians there were, the harder it would have been to defeat them. Yes, when it came to raw violence, the Europeans had the advantage of superior military technology. But they also had to travel long distances to fight, and they had to supply their armies over long distances. They were fighting in unfamiliar terrain while the Indians were in their homeland. Etc. Even if the Europeans had the raw power to win in the long run, as their death toll mounted, at some point they might well decide that it just isn't worth it. Like the collapse of the British Empire after World War 2, or the recent U.S. withdrawal from Iraq, or the Roman evacuation of the British isles ca AD 400. There have been many times in history when a big nation has the raw numbers and military might to defeat a weaker nation if they were willing to pay the cost in money and lives ... but they're not willing. RE morals: To Europeans, America was largely an empty continent open for the taking. The more Indians there were, the less viable this view would have been. While some Europeans had no qualms about massacring any Indians who got in their way, others had great respect for the Indians. In Columbus diary he describes the Indians as being pure and virtuous people because they were untainted by the evils of civilization. When one tribe told him that another were cannibals, he refused to believe that it was possible, writing in his diary that this must be a mistake, that now and then someone got lost in the woods and his family came up with wild stories about him being eaten by cannibals to explain why he never returned. The Pilgrims executed one of their own people for murdering an Indian. Etc. I think it's fair to say that the bloodier any conquest was, the more moral objections that would have been raised to it. So wow, where does all that rambling lead? It would almost surely have slowed down the European conquest. I think it's unlikely that it would have prevented Europeans from having any foothold in the Americas at all. After all, some of the early Spanish conquests were before the plagues really took hold. My gut feel is that, if enough Indians had survived, there could still be independent Indian nations today in the Great Plains of North America, maybe in Argentina and Brazil. But the Spanish would still have taken the Aztec and Inca empires and the U.S. would still be established east of the Mississippi. There'd still be white people in California, though who they'd be aligned with politically is hard to say. [Answer] The colonization of the Americas by Northern Europeans may not have happened. Fewer Native Americans lost to disease would have meant more people to fight the colonization. The Europeans would either have to bring more people over to fight them, given up (and gone home), or negotiated peacefully. Any of those three options would have left America with fewer Europeans colonizing it. ]
[Question] [ I would like to destroy a Dyson Sphere so it leaves big chunks of scrap metal with no habitable zones left, but still with enough structure to hold building-sized blocks. The destruction shouldn't be man made. Sphere Description (ordered from the sun to the outer layers): 1. Habitable Zone: cities, agricultural farms, places 2. Support Zone: electricity and water supply, first structure level 3. Main structure: the other structure levels where everything is built on. 4. Spaceports and Cargo System: an infrastructure on the outside where spaceships can dock and a network of "Trains" transport cargo 5. Shield Pylons: for shielding the whole Thing against little meteoroids and ships. I've described the hull of the sphere about 200 - 500 meters thick. What could make such an impact on the Sphere? How would the destruction progress after the initial "blow" hit the Sphere? ETA: This question has been refocused slightly, as such some of the answers below are a little out of date. [Answer] A Dyson sphere is not stable on itself, for a variety of reasons. On one side, since the sphere encircles completely the star, it does not feel the gravity, so it must be kept on place artificially. This means having rockets or jets of some kind, thus placing extra tensions on the structure. On the other side, the sphere can feel the variations of the gravity field caused by e.g. external stars that pass nearby, so it feels tides, which are not good for a solid structure. If the sphere does not encircle all planets (think on a Dyson sphere the size of Earth's orbit, to lye in the habitable zone) external planets cause tidal forces on the structure. Moreover, you have material fatigue. If your maintenance is not perfect (and it is hard to have perfect maintenance on a sphere with hundreds of millions of kilometers in radius - this is 10,000,000,000,000,000 square kilometers to maintain), the sphere will corrode (even if it is not metallic, there are gamma rays and free protons out there) and eventually tear apart. Moreover it is probable that the sphere fails on itself. Simply some vibration that happens to be in a normal vibration mode of the sphere (thus causing resonance) will destroy it. And then there are cataclismic events like large asterois or comets, etc. [Answer] What about the sphere being hit by a [cosmic string?](https://en.wikipedia.org/wiki/Cosmic_string) Some excerpts from the Wikipedia page: > > Cosmic strings, if they exist, would be extremely thin with diameters of the same order of magnitude as that of a proton, i.e. ~ 1 fm, or smaller. > > > [...] > > Even though cosmic strings are thought to be extremely thin, they would have immense density, and so would represent significant gravitational wave sources. A cosmic string about a kilometer in length may be more massive than the Earth. > > > [...] > > The only gravitational effect of a straight cosmic string is a relative deflection of matter (or light) passing the string on opposite sides (a purely topological effect). > > > Also on [this blog entry on how to destroy the earth](http://qntm.org/destroy) you find > > 1. **Whipped by a cosmic string** > > > **You will need:** a cosmic string and a whole lotta luck > > > **Method:** Cosmic strings are hypothetical 1-dimensional defects in spacetime, left over from earlier phases of the universe, somewhat like cracks in ice. They are potentially universe-spanning objects, thinner than a proton but with unimaginable density - one Earth mass per 1600m of length! All you need to do is get a cosmic string near Earth, and it'll be torn apart, shredded, and sucked in. Probably the entire rest of the solar system would be too. > > > **Earth's final resting place:** String. > > > **Feasibility rating:** 1/10. Mind-bogglingly unlikely. Even if cosmic strings do exist, which they may not, there are probably only about ten of them left in the ENTIRE UNIVERSE. And they can't be steered, unless you have godlike powers, in which case you might as well chuck the Earth into the Sun and have done with it, so you're relying entirely on luck. This. Will. Never. Happen. > > > **Source:** this method suggested by Dan Winston. > > > BTW, you might also be interested in some of other entries of the latter site; after all whatever can destroy the earth should be able to do huge damage to a Dyson sphere, too. [Answer] I would say that a few rocks aren't going to affect a Dyson Sphere, however, a passing brown Dwarf or even a White Dwarf, could put enough pressures on the whole system to truly disrupt it's functioning, maybe even tear it apart. The gravity between two stars would flex and bend the sphere. [Answer] I have several thoughts. Let's start with your opener - meteors, firstly they will need to be travelling at very impressive velocity to breach something half a kilometer thick! It's possible but I can't help thinking someone with the technology to build a Dyson Sphere could cope with a few stray rocks. Even damaging the outer skin in a single place would be fairly devastating to a sphere - assuming the inside is pressurised atmosphere would start to leak out dragging debris with it and causing massive damage. What about some tiny robots which worked their way through the weak spots of the superstructure? My first thought is could someone do something to the sun itself? Having already established there must be some seriously impressive technology behind this location could the inhabitants of the sphere harvest something from the sun which causes it to react badly? Could excess mining tip it to cause a either supernova, implode into a black hole, scorch the ground with flares, throw out lethal radiation... you get the idea? Finally physically destroying the sphere may be an option but there are more ways to get people to abandon a city other than blowing it up, there could be a sudden change of heart towards outsider or a plague, a famine. Perhaps your simplest solution is to look at real world reasons which force people to leave places. You may find these are a lot easier to explain than trying to undermine such advanced technology! Who knows, maybe the rush to escape or low maintenance will cause it's destruction in the long term. [Answer] Have you thought about having the meteors being like a thousand fist-sized meteors, explain it that because of the small size of each meteor they slipped past the sphere's defenses. piece by piece the meteor shower could destroy infrastructure to a point where it becomes unstable and thus requiring your party to leave. [Answer] An event from outside massive enough to damage the sphere or a structural failing of the sphere itself are both too prone to wreck the whole sphere, causing complete breakup of it. I thought of two things: 1) Some kind of calamity during construction that kills off or reduces capabilities of whatever being or race is building it. If the framework is already in place but not the 'land', you've got that framework you want. 2) The star changes somehow. If it grows or intensifies, the habitable area will be scorched at least, rendering it uninhabitable. If the star shrinks the habitable area will freeze over, rendering it uninhabitable. [Answer] Stars have a temperature difference over a long period of time. A Dyson Sphere, absorbing all of the energy from a star, would be sensitive to those changes over a period of time. This is described via the [Standard Solar Model](http://en.wikipedia.org/wiki/Standard_solar_model). An increase of, say, 10% could lead to a runaway climate effect on the entire sphere that isn't manageable, which could lead to it being abandoned. This will take a very long time to have a real chance of an effect. Beyond that, it could run out of fuel, and if that happened, then it would become unstable. Eventually parts of it would run in to the Sun, and would fall in lots of pieces spread all over the place. A scenario that this could happen is described in Ringworld, where essentially due to a lack of raw materials, the civilizations gradually regress in to a pre-technology civilization, where they eventually forget to fuel the rockets keeping it stable. Maybe these rockets even get stolen. In any case, if the Dyson Sphere is neglected for any reason over a lengthy period of time, it will cause some serious environmental issues, eventually having it fall in to it's host star. [Answer] If the sun in the center of the Dyson Sphere went SuperNova that would destroy the Dyson Sphere. It is in some way concievable that a small proportion of the sphere might survive. With that much matter to be destroyed it may be possible to postulate that some sections would survive. [Answer] Kinetic energy (from meteors) doesn't simply create damage at a point of impact, it also imparts acceleration onto the impacted body. Any\* motion of the sphere takes some part of it closer to it's parent star. Not only that but the motion will accelerate, as the closer to the star a mass is the greater influence a star's gravitation has over it. Your result is that the Dyson Sphere tears itself apart before it actually 'touches'' the star because one side(part, not hemisphere) of the sphere is under greater and greater gravity-induced acceleration whilst the other side is under less and less. If it's a '3d polygon' it seems to me you have to have an immensely resilient sphere to be able to apply sufficient counterthrust without wrecking your shell. Otherwise, you have two oppositional impacts. Firstly a dyson sphere is of course restricting the transit of mass from interior to exterior but not restricting the gravitational impact of the star. Under normal conditions a star acts as an attractor (gravity) and repeller (ejected massive particles) Some learned individual I'm sure could do the math if it's at all relevant.. But it seems to me that if your Dyson Sphere is not absorbing the same 'quantity' of force and mass that it#s Star normally ejects your Star is effectively gaining mass. And mass that would otherwise be repelled by solar wind etc et al..is now drifting inexorably towards your Sphere. It's all well and good saying "I shoot meteors with lazors" but that doesn't actually change where the mass that composed that meteor is being is being attracted to. Intuitively, that all seems plausible to me, but even so how long (if ever) such a process would take to materially impact your structure is entirely beyond my ken. ]
[Question] [ I'm working on a story right now where darkness plays an important role, and I had the idea to set my story on a rogue planet, a planet in perpetual darkness because it has no sun. However, from what I understand, heat and energy in this kind of system is hard to come by, which could make things a little boring if the entire planet is so cold nothing interesting can happen. So these are the elements I'm interested in providing to my planet: * Should be not frozen solid: It doesn't have to as warm as Earth, but warm enough that humans could live with life-support. Antarctic-level cold is about the minimum here, or about -100 °C. * Should be geologically interesting: I'd like it to be warm enough underground that humans may prefer living there instead of on the surface; I'd also like to see magma, but this is optional. * Should support life, though it need not be life-as-we-know-it. * Should be able hold an atmosphere. (EDIT: Originally there was a requirement for a semi-Earth-like atmosphere, but I've relaxed this.) Here's some more background on the planet, but feel free to adapt this as needed: * The planet is a (alien) life-supporting planet that was flung from it's solar system long ago. * The planet does *not* have to be Earth-sized, and will likely be much smaller. * Life on the planet somehow survived, though it has heavily adapted to the darkness. It is not necessarily intelligent, though it could be. * Due to the scarcity of energy, the natives tend to cluster around sources of energy, much like we have deep sea life that clusters around volcanic vents. To me, adding a moon (or moons, or even sister planet) seems to be the most likely way to make the situation more feasible and more interesting, so i'm especially interested in answers involving moons. (Bonus points(?) if the moon provides low light or is visible somehow.) But any solutions are acceptable. I'm willing to accept some handwaving. [Answer] Rogue planets can be kept warm. The key points can be found in the Wikipedia entry on [rogue planets](https://en.wikipedia.org/wiki/Rogue_planet). > > Interstellar planets generate little heat nor are they heated by a star. In 1998, David J. Stevenson theorized that some planet-sized > objects adrift in the vast expanses of cold interstellar space could > possibly sustain a thick atmosphere that would not freeze out. He > proposes that atmospheres are preserved by the pressure-induced > far-infrared radiation opacity of a thick hydrogen-containing > atmosphere. > > > The OP's rogue planet is geologically interesting, any geological activity can produce heat and with a dense hydrogen atmosphere this heat will be retained. If the rogue planet had a large moon, relative to its own size, or was part of a double planet, the tidal forces would drive increased volcanic and geological activity. Large areas of magma could exist akin to Deccan Traps. Good for additional planetary heating. If similar volcanic activity occurred on the large moon / double planet companion, this could be visible from the planet's surface. This wouldn't provide much illumination, but it could make its presence observable. This won't constitute a glow-in-the-dark moon, but unless you want to go full pseudo-scientific hand-waving, there aren't too many options. Radium moons or a moonscape covered with bioluminescent flora, for example, but neither of which will throw much light. Very much very low light levels. There is a good chance that a biosphere could develop. Most so in the light of what is known about the extreme conditions where life can survive. But this assumes the evolution of life on rogue planet as such, however, if the planet had its own indigenous alien biosphere it doesn't seem likely it would survive the transition from a planet in a solar system to a rogue planet. The principal exception would be if the planet possessed sapient lifeforms with sufficiently advanced technology to enable to survive the transition to a rogue planet. Especially if they were capable to preserving and saving enough of their planet's biosphere. Since their planet has been a rogue for a long time this should be enough to allow its lifeforms to adapt the conditions, with a little help from genetic engineering. Since Stevenson's proposal for habitable rogue planets required a hydrogen atmosphere, any oxygen present would either have to be extremely low or it would constitute a hazard to life and limb. In this case, there shouldn't be very much oxygen in the planet's atmosphere. The rogue planet's inhabitants may use oxygen and so it may be present inside their habitats, but generally in the atmosphere, no. If these conditions are meet it is plausible that a rogue planet could have temperatures comparable to Antarctica and below, but still at levels to make life viable. EDIT: There was an earlier question about perception on a Titan-like planet. One possible solution was infrared perception. Not eyes as we know them, but complex arrays of heat sensing pits. See this question [Evolution of eyesight on a planet with a methane biochemistry](https://worldbuilding.stackexchange.com/questions/48525/evolution-of-eyesight-on-a-planet-with-a-methane-biochemistry) If the alien lifeforms on a rogue planet either evolved or modified themselves for infrared perception their world wouldn't necessarily be one of absolute darkness. They might even lack any sense of difference between night and day (without a primary star that is meaningless anyway). The emitted infrared radiation from their moon might provide some additional illumination. In a double planet system, if you want to tidal forces to generate geological and volcanic activity, the two bodies will need to be close together. This probably means they will be tidally locked, with the same sides facing each other. At least, an apparently stationary moon will be a geographical reference point for the inhabitants. [Answer] @a4android's tidal heating answer was my first thought, too. Along those lines, the planet might have multiple moons, or artificial moons. With enough handwaving, a pattern of multiple moon orbits with electromagnetic interaction with each other/the atmosphere could result in some lighting and light effects. Related, but not identical ideas: * The "Spiders" from Vernor Vinge's *A Deepness in the Sky*: > > The plot begins with the discovery of an intelligent alien species on a planet orbiting an anomalous star, dubbed OnOff because for 215 of every 250 years it is dormant, releasing almost no energy. During this period, the planet freezes and its fauna go into hibernation. - <https://en.wikipedia.org/wiki/A_Deepness_in_the_Sky> > > > You could have your planet orbit a pulsing star which wasn't cold enough to let it freeze, but does let it get dark and cold. Or have its wandering route technologically directed to plot a course by stars which could periodically warm it up a bit. * The Pierson's Puppeteers from Larry Niven's *Ringworld* books - they put their entire civilization into debt to buy (handwaving technology) from outside the galaxy, so they could sent their planet *and its star* off into a wandering state - <http://www.technovelgy.com/ct/content.asp?Bnum=605> They have rogueness, and heat, but not darkness. But they could get darkness by being underground, as your other idea mentions. e.g. the humans in *The Matrix* lived underground for warmth because the sky is reflecting heat, the Eloi and Morlocks in H.G. Wells' *The Time Machine* have a surface/underground split for societal reasons and potentially for safety (you could have predators on the surface). E.M. Forster's [The Machine Stops](https://en.wikipedia.org/wiki/The_Machine_Stops) have people who live underground by ... habit? and are able to go to the surface, but don't because they think it's not for civilized people. * Jules Verne's *Journey to the Center of the Earth* has an idea when explaining that the center of the Earth is not too hot and molten, the Earth's heat is surface-only: > > "The earth has been heated by combustion on its surface, that is all. Its surface was composed of a great number of metals, such as potassium and sodium, which have the peculiar property of igniting at the mere contact with air and water; these metals kindled when the atmospheric vapours fell in rain upon the soil; and by and by, when the waters penetrated into the fissures of the crust of the earth, they broke out into fresh combustion with explosions and eruptions. Such was the cause of the numerous volcanoes at the origin of the earth." > > > "Upon my word, this is a very clever hypothesis," I exclaimed, in spite rather of myself. > > > "And which Humphry Davy demonstrated to me by a simple experiment. He formed a small ball of the metals which I have named, and which was a very fair representation of our globe; whenever he caused a fine dew of rain to fall upon its surface, it heaved up into little monticules, it became oxydized and formed miniature mountains; a crater broke open at one of its summits; the eruption took place, and communicated to the whole of the ball such a heat that it could not be held in the hand." > > > If this was at all workable, you could have a cold, dark and frozen planet, but with hot regions generated by ongoing chemical reactions between the surface and atmosphere. * Greg Egan's short story ["Hot Rock"](http://gregegan.customer.netspace.net.au/BIBLIOGRAPHY/Bibliography.html#p99) has a rogue planet called Tallulah: > > Tallulah had no sun; it had been an orphan for at least a billion years, drifting untethered through the galaxy. Yet distant astronomers had surmised - and the instruments here and now confirmed - that its surface was awash with running water. [..] when a planet was stripped of its sun, the decay of long-lived radioisotopes could eke out enough warmth over billions of years to keep its core molten. [..] > > > Tallulah was created by long-lost 'Builders', who created a 'deep rock' femto-scale technology, which turns iron and nickel into a hundred billion varieties of weird particles at 90% mass to energy conversion. The story has future-humans and aliens landing on it, trying to work out how it works. * *The Matrix* again, it has 'humans combined with a form of fusion' used as batteries to power the machines. That kind of idea, perhaps the life forms on the planet huddle together for some kind of unusual heat creation process. They can go exploring over the surface, but not spread out and live or stay there for long in isolation. * Not exactly related to temperature, but Terry Pratchett's *The Dark side of the Sun* has a sentient planet called The First Syrian Bank. It's a digital computer intelligence formed by plate tectonic shifts creating circuitry in a silicon based crust (IIRC). If you went with an approach like that, the planet could have its own unknown technology for keeping warm, and a motivation of keeping warm surface regions to encourage aliens to land, live, trade, communicate. At least fulfills the *The planet supports life, though it is not life-as-we-know-it.* part, and has lots of scope for why the temperature isn't very human friendly. * Peter F. Hamilton's *Void* Trilogy has a couple of variants of an ancient alien Arkship/warship crash landed on a planet and being embedded in the surface and lived in by other people. If it was a powerful enough ship, handwavy technology, it could have been enough to drive the planet out of orbit, energy levels drop a bit and cool down, now it's the main source of light and heat - heating the surrounding earth and melting rock underground around it - but not the entire planet. Life forms life within a region around the ship, without necessarily knowing what it is, or knowing about it at all (if it's underground). And of course, there's blunt technology - the planet is frozen and inhospitable, but the aliens have enormous nuclear reactors in craters. Each crater is a region of habitable land/underground, and a gaseous atmosphere kept from leaking out by gravity/frozen atmosphere dome overhead. Some nuclear reactors over time have gone wrong and melted regions near them, some attempts at drilling underground, trying to find resources, nuclear testing, have left relatively short lived molten regions deep underground. [Answer] I don't have time to research and write a full answer, so this will have to do, sorry. A low mass [Brown Dwarf Star](https://en.wikipedia.org/wiki/Brown_dwarf) with a habitable moon might allow what you need, due to orbital shenanigans the brown dwarf was ejected from it's solar system with it's moon. Now heat on the moon is generated internally by tidal forces, and some heat from the brown dwarf (depends on how near it is). The brown dwarf can have as much luminescence as you like, from as bright as sol to no visible light, just some infra-red (which sounds like it suits), and still be a brown dwarf. You've a rogue pair, and one is technically a star, but it might give you a habitable rogue world. [Answer] Suppose that the planet had almost completely frozen over with the remaining life clustered around geothermal vents. Then if one ore more moons, either through collision or by entering the Roche limit, were to break up and impact the planet, there would be significant heating. Keep your impacts small enough to not be crust-melting/atmosphere stripping but large and frequent enough to melt the ice and trigger a bit more geological activity. You can then have a (relative) bloom in native life for a geologically short period and it's clustered around vents, as you wanted. Light is a major problem. The best I can come up with is a glowing molten crust, which would of course have to be another body. So I would definitely go for a collision between moons as the source of the meteors and the molten moon, which is also what you wanted. The numbers are unlikely to pan out if you calculate this exactly but you did say you're game for hand-waving. [Answer] I had an idea that might be slightly out of the box. How about an Oort-cloud style set of asteroids and meteors in a fairly unstable orbit, such that the planet is bombarded relatively often. Whilst this presents some difficulties for the continued existence of life, the effects may not be that great, as the primary cause of extinction in events like this is a dust cloud blocking out light. [Answer] Try setting it in the distant past, before space was the frigid wasteland it is today: <https://arxiv.org/abs/1312.0613> interview: <https://www.nytimes.com/2014/12/02/science/avi-loeb-ponders-the-early-universe-nature-and-life.html?_r=0> ]