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[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/117773/edit). Closed 5 years ago. [Improve this question](/posts/117773/edit) The moon is made up of a substance that emits gamma rays. It bathes the planet in low levels of radiation, and has done so since humanity's inception. It is the same size that it is in real life, and the same distance from earth. The atmosphere is also similar to ours. How would this form of radiation benefit humanity and the rest of the planet? [Answer] I freely admit I'm reaching here: It would make the moon unsuitable for an alien invasion fleet to set up a command base there. Their standard invasion protocol requires them to set up a command base on a natural satellite, out of reach of the locals, before orbital bombardment can begin. They took one look at our dangerously radioactive moon, and decided it would be easier to invade someone else. [Answer] **It wouldn't be any different.** The Earth's atmosphere absorbs gamma rays. This is a good thing, because gamma radiation is not helpful for humans or most other life. [Answer] As Samuel said, there would be **no change to humanity whatsoever**. The gamma rays would not penetrate the Earth's atmosphere well enough to affect human DNA. However, depending on the strength of the radiation from the moon, we might see a stronger aurora effect. I think what would be more notable is the effect on our society's development. Let's assume the world developed the same as it did without the radioactivity. Consider these two scenarios: 1. Since so much radiation has to come from *something*, this means there could be a valuable radioisotope in the dust of the moon. NASA has been using [decaying radioisotopes](https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator) for long term power generation for decades. The prospect of unlimited energy has made the world more excited than ever before! Now capitalism has jump-started a gold rush to the valuable materials of the cosmos, causing massive investment in space exploration! 2. Conversely, society has scorned space travel! In the Space Race with the USSR, the United States exposed all those Apollo Astronauts to radiation, killing them a few years after the missions ended. As a result, Human Space Exploration has been **banned** because of the inherent risk. With NASA now gone, anti-science rhetoric is at an all time high. The boundary between church and state has begun to thin... [Answer] As jedmeyer mentioned, there would likely be no direct effects from the radiation. The earth already gets hit with a lot of high frequency EM radiation, including gamma radiation, and very little of it gets through the atmosphere. There would likely be quite a few secondary effects though: * Earth would have been warmer throughout it's history. All the extra radiation would be adding extra energy to the atmosphere, which has to go somewhere. How much warmer is hard to tell without exact numbers on the composition of the moon. This in turn, would likely have at least resulted in shorter ice ages, which would have had an impact on both evolution, and human society. * The exact atmospheric composition would likely be different, though by how much is hard to tell. It's well known that UV radiation is what produces almost all of the atmospheric ozone on Earth. Similar reactions occur for gamma radiation, though to a much lesser degree. * On the same note, lightning might be more common in the upper atmosphere. Ionizing radiation like gamma radiation can cause charge imbalan es that are conducive to creating lightning. Such effects occur relatively infrequently however (thermonuclear explosions for example can cause lightning, but it's mostly because of the atmospheric turbulence and charged particulates, not the radiation directly). * Man-made satellites would have lots of issues. Gamma radiation is a serious problem for electronics. It's possible to design systems that are radiation hardened, but they're far more expensive than regular designs. Most LEO satellites are not fully radiation hardened in real life, but in a world like you describe, they would have to be. * Human spaceflight will become almost impossible, with becoming an astronaut essentially being a death scentence. * The moon *might* look brighter in the night sky. * Baseline background radiation on the surface might be marginally higher (a few PPM at most). Anything that can be done to impacted by this would be, but the effects would be so small they likely would be unnoticeable except on a massive scale. That last part is where most of the theoretical potential benefits come in. Bacteria and other things that already have a particularly high mutation rate would likely evolve faster and scientists would have another natural random number generator. That's about it though as far as benefits I can think of. [Answer] One non-benefit: A seriously radioactive moon would put a big crimp in our space program. Just about everything that's been tried in deep space has been tried on the Moon first. If the moon is hot enough to bathe Earth in gamma rays it's hot enough to play major havoc with the electronics of any nearby spacecraft--you probably can't even orbit it. [Answer] You weren't very clear on whether "humanity's inception" was an inclusive or exclusive timeframe, but either way it presents a problem since it means the moon has either been outputting a large amount of energy over billions of years or somehow got "turned on" once humanity appeared. Still, the point is that this isn't natural at all and contradicts all current theories of moon formation. Therefore those theories are obviously wrong and the moon is giant spaceship parked there by ancient astronauts. The radiation might just be the first layer of automated defenses that will fall under the control of whoever first reaches the bridge of the Lunar class starship, gains administrative rights over the ship's systems, and inherits the legacy of the Precursors. Or if you insist on the radiation itself being helpful, it might be part of an electronic countermeasures package designed to protect Earth from detection by roving bands of von Neumann machines bent on devouring all organic life. [Answer] Now, if the radiation is coming from right below the surface from a claimable source, like radioactive isotopes, building a base on the moon might be more feasible. However, this depends on the amount that is radiated. Too high and there will be no space program, faint but detectable would work perfectly. We could have had project orion if the moon contained claimable nuclear material. [Answer] The periodicity that the moon brings via gravitational radiation (i.e. tides) creates a dynamic playground of wet/dryness that add complexity to the environment. This complexity is exploited in various ways by quite a few different organisms (consider a bird hunting in tidal pools, or a barnacle advancing further upshore). If the moon emitted gamma radiation, which acts as a DNA mutagen, life on earth would have a similarly periodic landscape regarding the rate of mutation that occurs during meiosis (which is when parent DNA combines to form child DNA). This would allow organisms to vary their behavior and in turn expect more or less variation in offspring. During times of dense population, or for parents that cannot offer a socioeconomic advantage, it might make sense to procreate when the moon is overhead--in hopes that the offspring benefits from the 1:1,000,000 shot that it will receive a beneficial mutation. On the other hand, during times of sparse population, or in cases where the parents can offer an advantaged situation, it would be better to "play it safe" and procreate when the moon is not visible. This would minimize mutation generally and be culturally a move that indicates support for the status quo. Realistically, I think that the x-ray moon children are just more likely to just be sickly--genetic evolution is not so potent on human timescales--but as a cultural phenomenon it might lead to an even stronger conservative/liberal divide than we have today. [Answer] It gives lifeforms an elevated tolerance to radiation. Since the entire biology on Earth developed under moderate radiation it adapted to that radiation by optimizing our DNA mechanisms. As an benefit, humans (and other species) are able to withstand high radiation levels without lasting damages. Advantages include fields as manned spaceflight, healthcare (less cancer) and nuclear industries. The main detriment is that governments have less scruple in using nuclear weapons. ]
[Question] [ Space is 3d. Which means complications when we introduce FTL travel and in imagining the fleets and their position. But in my story, FTL is easier beyond the reach of the sun and after the last planet, as the technology beyond FTL travel is effected by planets. So basically the easiest FTL 'jump' is the one between places of no planets or asteroids or suns. So let us imagine the solar system in a a simplified way like in Mass Effect or in [this](https://i5.walmartimages.com/asr/2eba49dc-08fa-4166-8720-a2172e90afcc_1.ddab208a60f5683a8c24ca06692026ce.jpeg) image or in [this](https://i.dailymail.co.uk/1s/2020/01/13/15/23345186-0-image-a-17_1578929974592.jpg). So the aliens have to appear 'beyond' Pluto. Now here is what I actually need for my story. **Humans need to find out about them. One week in advance** Now I have zero idea about our current space observations capabilities so I don't know if it is possible now or not. If it is not possible I guess the story can be set a couple of decades later. But then what do I need? Like actual technologies, not handwaving it with: advancements. For example can the current Kitt Peak National Observatory in Arizona detect them? Two important points: Space is big. And we probably, like I said I know little of our astrophysics, are not monitoring every part of it. True. But such a jump is very 'loud' and when the fleet arrives there is a a release of energy there. So we probably should be warned. They have FTL travel. They can just do what they want including arrive at earth in an instant. The aliens speed is not an issue as they are having all sorts of problems regarding their technology and fuel. So they are not using their full tech. Also FTL travel is not doable inside the dead zone of the sun. That's a whole thing in my world but basically means that they are using advanced thrusts to move inside of any solar system. This again is like drawing imaginary lines starting with the sun and ending with the last planet. Anything withing the line of the last planet is a dead zone. After that FTL travel opens. [Answer] With current human technology the alien craft would have to be either extremely large (and visible) or very, very noisy for us to detect it anywhere outside the orbit of Mars. So either they're flying around in a polished chrome planetoid or their method of travel produces phenomena that draw our attention. Our best optical instruments are unlikely to detect them at any reasonable range if they're not planet-sized... or at least small moon size. If the Death Star warped in and sat somewhere on the orbit of Pluto we probably wouldn't notice it for a few years at least. It wasn't until 2005 that we managed to get an image of Nix (Pluto's 3rd moon, although it was the 2nd until they found Styx in 2012) using Hubble, and Nix is about 31 miles long *and we were looking for it*. As far as I can tell Hubble never managed to get a discernible image of Styx or Kerberos which are both much smaller. So unless your alien ship is extremely large the odds of a visual survey noticing it in the next few *decades* are vanishingly small. In order for humans to even start looking we'll need a fairly strong signal source to alert us to the fact that there's something to look for. We'll also need a couple of weeks to get the various observatories re-tasked before they can even really start looking in the right place. There's bound to be a radio observatory like Mauna Kea that can do it quicker, but you probably won't get time on Arecibo inside of a 6 months unless you've already found the object and people are starting to panic. Honestly, the only way we're even going to notice them coming is if they're making a *lot* of noise on a fairly clean EM band. They'd have to be sending a few megawatts in our general direction to get noticed in days from that distance. The closer they get the better our odds, so I'd advise that they take their time on in-system drive. If it takes them 2 weeks to get here then they'd better be raising all kinds of hell on the way or there's no way we're even going to notice. We'd maybe figure it out a couple of days before they passed the Moon's orbit. Maybe not. As for near-future technical advancements, it's unlikely that we'll have anything of interest in the next couple of decades that can really improve the detection odds. In another 50 years or so we might have a functional far-side radio telescope that makes Arecibo look like a portable radio, but it won't do you much good unless it just happens to be pointed in the right direction at the time. A lunar optical observatory would be nice, but again limited by the Moon's orientation at the time. Give it a hundred years or so and we could find out about the aliens when they destroy an inhabited station or ship out in the outer solar system. A frantic radio call for help would probably get the attention needed to search for the aliens. [Answer] As the main point is "Humans need to find out about them. One week in advance", I'd like to offer a new option: **We were lucky**. As @Corey mentions in [this answer](https://worldbuilding.stackexchange.com/a/185154/38707): > > (Pluto's 3rd moon, although it was the 2nd until they found Styx in > 2012) using Hubble, and Nix is about 31 miles long and we were looking > for it. > > > Why don't you do your people to be looking at that place **AND** an UFO appears in the screen? You may use all the useful info from the other answers but you don't really need to be so technologically advanced. Something like: > > "The researchers were looking at Nix and something unexpected > appeared, let's look closer. Gosh! Look at that, what is that > object?!" > > > [Answer] As for detection, the warping out of FTL may create a radio burst that will be picked up by radio telescopes on Earth. It has a very unusual signature, making astronomers direct their telescopes towards the source. They can then spot the exhaust from the alien's engines as they decelerate towards the Earth (the fastest way for the aliens to reach Earth would be to arrive at high speed and then decelerate at maximum thrust to reach Earth with near-zero velocity). Let us assume that the maximum deceleration that the aliens can stand for extended periods is 30 meters per second squared (three gravities). Then the maximum speed towards Earth they could arrive with at 5 billion km (a bit outside Neptune's orbit) and still brake would be 17.300 km/s, and it would take 160 hours (6 days, 16 hours) to reach Earth, arriving with near-zero velocity (to enter orbit). This gives you roughly the week you ask for. To extend the time a bit, slightly increase the initial speed and distance or reduce the deceleration. As for what kind of engines the aliens need, the output would have to be rather extreme to achieve an acceleration of three gravities. The only engines we know of that can do this are chemical ones, and they should have a very visible output. Ion engines have a better fuel-mass-to-thrust ratio but need heavy reactors produce the thrust, resulting in low acceleration (that in turn can be maintained for a very long time). The aliens could feasibly have a matter/antimatter drive that uses the annihilation photons for thrust. Electron/positron produces photons of 511 keV, while proton/antiproton annihilation produces photons of 938 MeV. Both would light up on gamma-ray telescopes like the [Fermi Gamma-ray Space Telescope](https://en.wikipedia.org/wiki/Fermi_Gamma-ray_Space_Telescope) and instantly catch attention. At any rate, it would be difficult to imagine that any engine using non-handwavium technology to provide such an acceleration would *not* be easioly detectable on Earth. [Answer] ### They aliens' arrival emit gravitational waves when leaving FTL. [LIGO](https://www.ligo.caltech.edu/) detected it. The alien fleet's FTL technology emits a burst of gravitational waves when they leave supra-luminal speeds. The fleet needs to be big, massive, but not that much. IRL, gravitational waves are only detected when cosmic events in the scale of black holes fusing or supernova explosions, but these are thousands of light-years away. Since they decay at 1/r and not 1/r2, the fleet needs to be a sizeable one to create detectable waves. Compare the required energy/mass in proportion to the square of the distance to "beyond pluto's orbit" (e-4 LY^2) to the square of the furthest black (e+9 LY^2). The magnitude of the gravity waves produced by the aliens need to be around e-13 times the waves produced by the black hole merger. > > A typical stellar-class of black hole has a mass between about 3 and 10 solar masses. [ref](https://www.nasa.gov/vision/universe/starsgalaxies/Black_Hole.html) > > > So your alien fleet doesn't even have to be massive. A solar mass is about 1.989e+30 kilograms. Multiplying all that, the fleet needs to cause gravitational waves as the collision of a mass in the order of e+17 kilograms, or in the ballpark of a hundred million times the mass of an oil supertanker ships. That's way smaller than the Star Wars' Death Star [ref](http://www.tdgutierrez.com/2017/07/28/part-ii-mass-of-the-death-star-in-episode-iv/). > > An oil tanker's weight is in the 10e+9 kg order of magnitude. [ref](https://en.wikipedia.org/wiki/Oil_tanker) > > > Your fictional alien motherships will need to be be bigger than that. The only thing your FTL technology really needs is to emit gravitational waves. The rest is covered. LIGO can pinpoint direction, so scientists will know exactly where to look for, and maybe spot your aliens within your timeframe. [Answer] So you want us to detect an alien fleet arriving out beyond Pluto's orbit and we have a one week deadline. @Corey has very clearly ruled out our seeing their arrival by visible-light observation. Adding to those arguments, there is also a significant possibility that the sun will be obstructing our direct line of sight to Pluto during many moments of our orbits. If they arrive during any of those moments, our chances of detecting their arrival goes from highly unlikely to near impossible. So let's see how else we might know they have arrived... They are utilizing FTL which is something we currently have no scientific explanation for. So if we don't know how it works, we also don't know what side-effects it might have. Perhaps all of our nuclear reactors suddenly flare or dim as the physical laws of the universe ripple as the aliens come out of warp "nearby". Perhaps our cyclotrons release new unexpected particles during the instance of their arrival. Maybe our quantum computers all start suffering an identical rounding errors just because an inactive FTL drive is inside of the dead zone. We might not know what any of these things mean when they happen, but we would know that something strange is going on, and in response, we might start watching distant space with more effort than we currently do. [Answer] **You can see them when they arrive.** This seems a little goofy to say, but, the simple answer is just that they emit a giant flash of visible light when they drop out of FTL. Something extremely bright in the visible spectrum is WAAAY more likely to get spotted because we have about 8 billion people, a significant fraction of whom like to look up at the night sky as a recreational activity. Hobby astronomers spot interesting new stuff before professionals all the time, so it doesn't need to be a flash big enough to spot with the naked eye necessarily. Subsequent confirmation within a decent timeframe (a couple weeks) is well within current tech, we can certainly 'see' something that far away in somewhat decent detail, we just have to know there is something in that section of the sky to look at. [Answer] **Neutrinos** If their braking propulsion is showering inner solar system with narrow beam of highly energetic neutrinos from exotic nuclear reactions, they are detectable with existing neutrino detectors and it is possible to determine the direction. Theoretical models of such propulsion already exist. It is possible to check the source with existing x-ray and gamma-ray telescopes/spectrometers whether the spectrum conforms to these models. Compared to visible spectrum and radio, the x-ray and gamma-ray space background is quieter and aliens would stand out much more. This way it can be determined that it is artificial process and measured their speed by doppler shift. [Answer] # We detect their STL rocket burns. One week from Earth to Pluto would require one heck of a rocket burn. Given a time of 3.5 days (half the time used for acceleration and half for deceleration) and a distance of 33 AU, we can calculate their acceleration as being approximately 96 m/s, or approximately 10g, and a maximum speed of .097c (the relativistic factor of which is still approximately 1, so we can neglect relativistic effects here). That is a very powerful level of acceleration sustained for a very long time - it would require either some form of superscience reactionless drive, or an extremely powerful nuclear rocket. The amount of energy such a rocket would produce would likely make it one of the brightest objects in the sky - though how bright would depend on how much mass these ships have. [Answer] Space is big and your alien ship is small, so the odds that someone notices it are very low. It's incredibly difficult for such a (relatively) tiny object to draw our attention at such extreme range. A much easier approach is for the ship to go somewhere we're already looking. Have ship approach along the vector between Earth and [Polaris](https://en.wikipedia.org/wiki/Polaris). This is a very prominent star that is perhaps the most important star in the Northern hemisphere for navigation purposes. Every amateur astronomer knows how to find it, and it can be seen with the naked eye. People are always looking for it for reference purposes. If your ship came in along a trajectory that blocked the view of Polaris, people on Earth would notice it pretty quickly. Stars get eclipsed all the time by objects moving through space, but your ship would block the star suddenly and unpredictably, and the star would remain out of sight for an extended period of time. That's definitely not normal, and would draw attention fairly quickly. [Answer] I think the most likely way to detect them is if the fleet (their engines or some other of their devices) were to produce radio noise. Considering it would be a by product of a device and not an intended signal its emission may be erratic. But still something unusual enough to be picked up and drive attention on. Pinpointing the source from different radio telescope stations astronomers would be able to find the location of the emission and in that position it would have no astonomical explanation. Furthermore acceleration by the fleet would not be consistent with the gravitational field and so raise even more attention to the unexplained phenomenon (see all the fuss that [Oumuamua](https://it.wikipedia.org/wiki/1I/%27Oumuamua) made). If you have to be detailed about it check the frequencies that radiotelescopes use. [Radio telescope](https://en.wikipedia.org/wiki/Radio_telescope) > > Channel 37: 608 to 614 MHz. > > The "Hydrogen line", also known as the "21 centimeter line": 1420.40575177 MHz, used by many radio telescopes including The Big Ear in its discovery of the Wow! signal > 1406 MHz and 430 MHz [7]. > > The Waterhole: 1,420 to 1,666 MHz. > > The Arecibo Observatory has several receivers that together cover the whole 1–10 GHz range. > > > I would suggest the [hydrogen line](https://en.wikipedia.org/wiki/Hydrogen_line) as it also may have plausable explanation of emission by alien technology. The signal may be faint considering it is not focused to Earth and spreads out in a sphere from the fleet but (for story reasons) has to be picked up. So at the source the emission should be very powerful. Engines first come to mind. I would suggest to avoid having the FTL arrival to produce the signal because it would be an instantaneous event, much more likely to be missed. And it would mean further observation and confirmation would be impossible. Astronomers would not be able to go from "a strange radio signal from that direction" to "an alien fleet is coming towards us!". The aliens may be aware of emitting radio noise and not care. Or just underestimate human technology. Usually a good engineer would shield that. Maybe they are having technical problems as you mention? The signal would take from 7 to 4 hours to reach Earth from Pluto (depending if Pluto is at its farthest or closest to Earth). **One week only seems a tight costrain though**. Consider that astronomers would verify their observations before coming out to the public or to their government. Observations would need to be performed by different radio stations on Earth in order to do the triangulation necessary to locate the source. More stations are also needed due to Earth rotation. As the signal will set for one station another will pick it up. P.S: Unrelated question: why would the aliens need to arrive near Pluto? How about arriving above or under the plane of the solar system? [Answer] **Anyone looking up** I'll assume their engines are reaction engines with 50% efficiency. Their ship is the mass of an aircraft carrier -- about 100 million kg. Going from twice pluto's orbit (100 au) to the sun is $2 \* 10^{10} km$. $2 \* 10^{10} km = \frac{1}{2} a(1 week)^2$ gives us $82 \frac{m}{s^2}$, or just shy of 10 Gs of acceleration. At 50% efficiency, this thrust is $4\*10^{17}$ Watts. Solar irradiance is $0.873 \frac{W}{m^2}$ at Pluto's distance from the sun. So the ship is as bright as a perfectly circular reflective mirror of radius 1 million km, or 1000x larger (in each dimension) than Pluto. While it is hard to see Pluto at that range, something literally a million times brighter... Pluto is magnitude 14 brightness. Each step is 2.512, so 1 million times brighter is magnitude -1. Pluto isn't a perfect reflector, so the ship would be a bit brighter; call it 1 more magnitude. A magnitude -2 object is brighter than the brightest star in the sky. On a clear night, anyone looking up on the right side of the planet would see it. Even if their engines are less bright than this, it would have to be much much much much much less bright not be spotted by curious amateur astronomers. Basically, trust is bright. It takes a lot of energy to move fast, and energy use means emitting light; entropy doesn't really give you other options. [Answer] I won't type a huge answer with a bunch of math because other people have already done that, and the math checks out. What I will do is give you two points that will help get the gears turning in a more creative way, plus one means of detection that I don't think anyone has mentioned yet! 1. Regarding the one week deadline from detection to arrival: the distance between Pluto and Earth is 4.6 light-hours, which simply means that travelling exactly at the speed of light it would take them 4.6 hours to make it to Earth. Since they are having tech problems, and they're starting slightly beyond Pluto, you can basically adjust these numbers however you want to make it work out for the story. Example: if 1.00c = 4.6hr travel time, then multiplying the travel time by roughly 36x would give you a travel time of 168 hours, or almost a week. That would be (1/36)c, or 0.027777c, or 2.7% the speed of light, which is completely believable for a species capable of FTL travel but currently experiencing some technical difficulties! Feel free to customize this based on your needs, or even do something like require the ship to slowly accelerate and build up speed, which changes the equation. I didn't consider this until now, but if the typical FTL drive is broken on the ship, they will need to resort to conventional means of acceleration, which will result in G-Forces being exerted on the crew. They may not be evolved for that, and it won't be an insignificant amount of G-forces either; it would probably kill humans to accelerate like that. I don't know exactly what the Gforces would be, but there are some physics calculators online that are based around F=ma, and will tell you the acceleration required to reach a certain speed in a certain amount of time, and then you can look a that acceleration and compare it to the acceleration of Earth's own gravity (9.8 m/s^2) which is one "g" of acceleration, to see how strong it would really be. They'll need to use some kind of tech that we don't have yet to cancel these g-forces, like "inertial dampeners" which have been a staple in science fiction for decades but don't have much basis in reality, or maybe a shield that provides a different "frame of reference" inside the bubble, so from the ship's perspective and the perspective of the crew inside the ship, it doesn't feel like you're moving at all because the shield bubble is like a bubble of "still" space, but the bubble can accelerate through our space as fast as it wants to, or as fast as their malfunctions allow them to. This is similar to how the Alcubierre Drive would work, except it would only be a bubble of local space around the ship and wouldn't have any type of physical shielding capabilities. NOTE: The information being received by scientists/military on the ground will be 4.6 hours out of date due to the distance and light delay. This means that when the scientists first spot the ship and make the prediction that the ship will reach Earth in roughly 168 hours, the ship actually appeared 4.6 hours ago and began moving then, giving it a 4.6 hour head start. The scientists should be aware of this, as physicists have known about light delay for hundreds of years and have been dealing with it personally since the dawn of radio communication. Also, as the alien ship gets closer and closer, the light delay will shrink and shrink until it gets to 0 (light delay from Earth to the Moon is about 1.3 seconds for reference) so it isn't like the alien ship will just appear on Earth when it looks like it is still 4.6 hours away. 2. Regarding the detection: we currently have some pretty new devices called gravitational wave detectors that we are using to gather information about fast rotating black holes and pulsars. You're right there would be a "BANG!" when the ships jumped back to local relativity, but it wouldn't be a sound wave since space is a vacuum. While there could certainly be a blast of radiation released when the ship drops out of FTL speed (as is theorized would be released by an Alcubierre Drive, which is one of the current ideas for a true FTL drive) there will also be "gravitational ripples" released by the sudden appearance of large ships. Usually, there are NO such ripples ever caused by matter appearing or disappearing suddenly, other than at the quantum scale. Even when a star explodes, nearly 99.9% of all the matter is still there, it's just expanding now. Similarly, when matter is sucked into a black hole, all the matter is still there contained inside the black hole: the mass of the singularity just rises based on the mass it is consuming. However, for matter to just appear seemingly out of nowhere? Even at the edge of our solar system, this could be detectable to us as a gravitational anomaly just like the ones that the LIGO and VIRGO groups began researching in 2015 when looking at pulsars and binary star systems far away from us. It would really probably be more like a "gravitational shockwave" since there will have probably never been readings like this before, especially if the ships are large, there are extremely many of them, or there are a lot of normal sized ships but one massive mothership that also appears. The radiation burst and, later, images from orbiting telescopes, could merely server as a confirmation that you're dealing with aliens, but you could make the initial detection via gravitational wave equipment to take advantage of some brand new technology in a way that would make all the scientists scratch their heads initially. Good luck on this, it sounds awesome! [Answer] As you point out, space is 3D. So, don't forget that our solar system is (mostly) a flat plane with Pluto being a little off of that plane. Depending on your alien FTL technology and the interference of planets, the fleet could arrive directly above or below our plane - perhaps allowing them to be closer to Earth for detection. As for detection methods, radio waves, gravity waves, supernova light bursts, etc. could all trip a sky survey mission here on Earth and raise awareness. [Answer] One alternative the the "FTL jump" or warp drive approach is to have their interstellar technology use some sort of wormhole. (Optionally require a device like the *Mass Effect* mass relay at the origin point to generate the wormhole.) Lots of scifi has the ship open a wormhole instantly, accelerate in, and then pop out instantly, but you can certainly stretch it out to have the wormhole take as much time as you'd like to fully materialize/open wide enough for the fleet to come through. Maybe it takes a week, maybe it takes a month -- plenty of time for people to get curious about some weird point-source radiation or gravitational waves or accidental radio transmissions through the baby wormhole and have someone pointing a telescope in the right direction when the fleet starts coming through. [Answer] # Detection The detection question is easy: we can't. It's not like in the movies. We don't have telescopes sweeping the sky like radar. We can't zoom and enhance. To get an idea of Earth's detection capabilities, just look at [our best picture of Pluto taken from Earth](https://web.archive.org/web/20110629005310/http://www.boulder.swri.edu/%7Ebuie/pluto/hrcmap.html) (actually Low Earth Orbit). [![enter image description here](https://i.stack.imgur.com/Z2t2S.png)](https://i.stack.imgur.com/Z2t2S.png) This is a composite of hundreds of images taken over the course of a year by the Hubble Space Telescope, and it is 1000 km wide. If your spacecraft is 1km wide, huge by spacecraft standards, it is 1000 times smaller than Pluto and would be a single pixel, if that. # An Extrasolar Maneuvering Object! We do now have some [wide-field instruments](https://en.wikipedia.org/wiki/Wide-field_Infrared_Survey_Explorer) and [sky surveys](https://en.wikipedia.org/wiki/Astronomical_survey) constantly sweeping the sky looking for minor planets and asteroids, but at the distance of Pluto a ship-sized object would not even register. Your ship would eventually be spotted as it moved closer, much closer, and would be registered just as some new asteroid. Scientists would take note of the new object, more telescopes would start observing to determine its orbit, and they'd eventually notice a few things. First, it's headed for Earth. This would get it more attention as a possible threat to Earth. This would not cause a panic, we detect these all the time, and as we take more observations and get a more accurate orbit we're more and more confident it will miss. But observations will reveal the next issue... It's extrasolar! Meaning its orbit indicates that it must have come from outside our solar system. The discovery of ['Oumuamua](https://en.wikipedia.org/wiki/%CA%BBOumuamua) recently caused a stir, but it was still a scientific curiosity. This would cause more observations. Eventually they'd realize... It's maneuvering! A hunk of space-rock should follow a predictable orbit around the Sun. Any corrections and maneuvers the ship makes would cause it to not follow predictions. However, unless it's something really dramatic, there Earth scientists would *still* not label it a spacecraft and would be *extremely* hesitant to do so. There are plenty of reasons for ["non-gravitational acceleration"](https://en.wikipedia.org/wiki/%CA%BBOumuamua#Non-gravitational_acceleration) and scientists will search for a natural explanation. As the ship gets closer to Earth it will have to maneuver more dramatically to achieve Earth orbit and the evidence will mount that there can be no natural explanation, or it will get close enough that it can be directly imaged. By that point, the ship is practically on top of us. # Extremely fast, but still slow. Because our detection capabilities are so bad, and because it would take us quite some time to determine that it's not a natural object, your spaceship has to move quite slowly... but still far, far faster than any man-made object. For example, the journey from Earth to Mars takes months, in part because we're coasting most of the way. New Horizons, one of the fastest spacecraft ever, took almost 10 years to reach Pluto. So you can choose however fast you like for your spacecraft to go to get your week, it will still be fantastically fast compared to Earth spacecraft. --- > > *So basically the easiest FTL 'jump' is the one between places of no planets or asteroids or suns.* > > > If so, that ship will have to come out of FTL waaay before Pluto. # Which is the last "planet"? What is and is not a ["planet"](https://en.wikipedia.org/wiki/Planet) is decided less by physics and more by human definition. For example, Pluto is no longer considered a "planet" by humans, it is a "dwarf planet", but that should not affect an alien's FTL drive. There's plenty of [other dwarf planets past Pluto](https://en.wikipedia.org/wiki/List_of_trans-Neptunian_objects), including some, like [Eris](https://en.wikipedia.org/wiki/Eris_(dwarf_planet)), which are more massive than Pluto. In addition, the solar system doesn't just stop at Pluto. There is the [Kuiper Belt](https://en.wikipedia.org/wiki/Kuiper_belt) which is a second asteroid belt far larger and more massive (but less dense) than the belt between Mars and Jupiter. Neither of these are very dense at all, certainly not like depicted in the movies, and we send spacecraft through hem all the time. # Neptune... or Saturn. As you say, FTL drives are affected by gravity, but Pluto and other Trans-Neptunian Objects are far, far too small and spread out to have an influence. Instead I'd suggest they need to drop out of FTL because of the first really massive object which can influence its entire orbit: Neptune. It is nearly as far out as Pluto, and it is massive enough to be a plausible influence. Or you can decide Neptune and Uranus were on the other side of the solar system and it jumps in near Saturn. It really doesn't matter, we still wouldn't see it. --- # Just Don't Mention It. In the finest tradition of good sci-fi, if you don't have to explain it ***don't explain it***. Especially if you're not an expert in that field. Since our detection capabilities are so bad, you don't have to explain the details at all. As above, the first Earth will know of it is vague observations of some new asteroid. If it comes up later in the story, all you need the aliens say is their FTL drive is influenced by gravity and they had to come out of FTL because they got too close to the Sun. Done. [Answer] Behind Pluto are alot more small Objekts. Ultima Thule for examle is 30 km long and was detected 2014. The New Horizon Misson went first to pluo and than to this rock. So its possible. Now a lot of Teleskopes are looking for Planet 9 much furher outside. They are looking for tiny peaces of light. That increases the chance findign it. You culd say it was just luck or you use the Radiation from your FTL witch could be very bright. It dosen't need to be bright in the visible spctrum. a lot of telescopes are using infared or ultraviolet. ]
[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/104261/edit). Closed 5 years ago. [Improve this question](/posts/104261/edit) Mounted in the middle of the Colonist main military base is the Massive Energized Particle Railgun. A BFG (Big Freaking Gun) able to draw on an effectively endless amount of power in order to charge up, and which point it is capable of firing a 1,000 ton “bullet” out of the atmosphere at relativistic velocity and into space. Obviously, once in space the bullet can keep its trajectory forever without slowing. Since the bullet is really an RKV (relativistic kill vehicle, or a big thing going REALLY fast), whatever it hits will be destroyed, as the impact will release more energy than a matter/antimatter reaction with the same mass. Hang on though, wouldn’t this mean that this gun could destroy any planet in the galaxy if given enough time and accurate information about said planet’s orbit? That’s not really conflict that’s holding a gun to the collective head of the rest of the galaxy. So is there some reason that this BFG could not hit another planet? If not, is there some way that a planet could defend against this galactic scale weapon of mass destruction? [Answer] First, some problems. # Your BFG isn't Big enough. > > *Wouldn’t this mean that this gun could destroy any planet in the galaxy?* > > > Depends on what you mean by "destroy". A 1,000 ton projectile at 0.9c is about 1e23 J. This is a lot, it's about 1/4 the energy of the meteor that killed the dinosaurs, but the impact will not "*release more energy than a matter/antimatter reaction with the same mass*". It's roughly the same. Getting smacked by a dinosaur killer is bad, but it won't destroy the planet. A civilization advanced enough to be worth expending 1e23 J on can recover ***and fire back***. We'll get to that. You can, of course, pump this thing up with as much energy as you like. At 0.999c it's 2e24 J, but it still isn't a planet cracker. More like a major ecological disaster. # Sorry about your atmosphere. > > *firing a 1,000 ton “bullet”* ***out of the atmosphere*** *at relativistic velocity and into space* > > > This 1000 ton bullet has to plow through your atmosphere adding drag, reducing it's final velocity, and greatly increasing the amount of energy you need to fire it. Worse, it will compress and heat the atmosphere creating an enormous fireball at the launch site doing a lot of damage to your own planet. 1e23J is roughly a week's worth of sunlight for Earth. One shot will disrupt weather patterns. Fire a few of these and you'll cook your planet. The first victim of the BFG will be the ones who fire it. This needs to go on a moon with no atmosphere, or in space. # How do you get it that fast? Assuming you have the energy, and we're talking ["Type II Civilization"](https://en.wikipedia.org/wiki/Kardashev_scale) levels of energy, how do you apply it to the projectile without obliterating it? This is the basic problem of a rail gun, how do you accelerate an object to relativistic speeds before it leaves the "barrel"? You could make the barrel longer and longer and longer, but at 0.9c this thing will go the diameter of the Earth in 47 ms. Not a lot of time to apply energy. Better to use a ring accelerator. Basically a giant [cyclotron particle accelerator](https://en.wikipedia.org/wiki/Cyclotron). The projectile spins around the ring, going faster and faster, held in the ring by powerful magnets. When it's reached its final velocity, the magnets release and it goes flying off. This would take *even more energy* to hold the projectile in the ring while its accelerating. The bigger the ring, the less energy necessary. So let's build a big ring. # Everyone Will Fire Back The problem with a purely kinetic is whoever gets hit can trace it right back to you. And they're going to be pissed. And they'll throw whatever they have left at you. As before, this is Type II Civilization levels of energy. Presumably your enemies are also Type II Civilizations to be worthy of such an investment which means they have more than one planet, and ways at striking back at you. Even if they don't, everyone else is likely to be pissed and come to destroy this threat to the galaxy. # The Big Falcon Ring This can't be in an atmosphere. It has to be huge. It needs enormous amounts of energy. It needs time between shots to gather energy and accelerate the projectile. Pick a large moon with no atmosphere and build the ring on the surface (turns out this isn't going to work, see below). [As others have pointed out](https://worldbuilding.stackexchange.com/a/104278/760), you'll need several rings to be able to fire at all points in the sky. Putting it in orbit doesn't help. Mine the moon itself for material. Put solar arrays in orbit to power it all, possibly even a [Dyson Swarm](https://en.wikipedia.org/wiki/Dyson_sphere#Dyson_swarm) around the star. The amount of energy needed to keep the projectile in the ring path is related to its [centripetal force](https://en.wikipedia.org/wiki/Centripetal_force). The formula for relativistic centripetal force is $$F = y m v^2/r$$. y is [The Lorentz factor](https://en.wikipedia.org/wiki/Lorentz_factor), $1/\sqrt{1 - v^2/c^2}$. This accounts for relativistic velocities. * v = velocity, ultimately 0.9c * m = mass of the projectile, 1000 kg * y = the Lorentz factor, ~2.3 at 0.9c * r = radius of the ring The force necessary to keep the projectile on a circular path is inversely proportional to the size of the ring. Double the size of the ring, halve the force necessary to keep the projectile in a circular path. Starting with the radius of Earth's moon, 1.7e6 m, we get $F = 1000 kg \* (0.9c)^2 / 1.7e6m$ or about 1e14 N. This is a lot. A Saturn V rocket puts out about 1e7 N. However, we can scale this down by scaling up the ring. Put it at Earth's orbit, 1 AU, and we're down to 1e9 N. Assuming the force is exerted over 1 m^2, this is 1 GPa inside the yield strength of steel. Stronger and more exotic materials, like [graphene](https://en.wikipedia.org/wiki/Graphene) with a tensile strength of about 100 GPa, would allow a 0.01 AU ring or a "mere" 1.5e6 km. Sci-fi materials would make it even smaller. Put it in a system that isn't terribly important to you, because that's where everyone will trace your shot back to, and that's where everyone is going to direct their ire. The ring need not be orbiting the Sun, it could be at a stable [Lagrange point](https://en.wikipedia.org/wiki/Lagrangian_point). I can't underscore enough just how large a project this is, even for a Type II Civilization. # The BFG needs Big Falcon Power. We can calculate the forces involved for the cyclotron gun at maximum velocity. The force required to keep a *non-relativistic* projectile in the ring is F = mv^2/r. For your 1000 tonne projectile at 0.9c on something like the Earth's moon it's about 5e16 N: a lot. To put this in perspective, 5e16 N is the equivalent of lifting everything humanity has ever made 1 meter up in 1 second. And that's before relativistic considerations. Putting aside the question of how you'll build a moon sided cyclotron that can withstand 5e16 N of force, something very, very large will have to power this. Not only is this a major investment by your civilization, but it's vulnerable to attack, and vulnerable while its being built. You'd need to pretend its some sort of civilian project. But once it's fired your cover is blown and it is vulnerable. Like a nuclear weapon its role is a balance of terror. Once you use it its value to protect yourself is lost. # How Fast Can You Fire Again? This thing needs enormous amounts of energy. And it needs time to accelerate the projectile. And the apparatus might be damaged in the firing. How often can you fire it? This is largely up to you. You can tweak the numbers for your story. If it's once a year, then they can get maybe 4 or 5 shots off at a close neighbor before anyone realizes what's happened. Maybe it's longer. Maybe its shorter. Narratively it gives time for the attacked civilization to react before another shot can be fired. Even better if they know they're doomed. The first shot has already landed, maybe somewhere relatively unoccupied to limit the immediate damage. They know more are already on the way and they can't stop them. But they can try to destroy BFG before it harms anyone else, and launch themselves at it knowing by the time they get there their planet will probably be wrecked. # Time On Target If your civilization wants to be *really* smart, it conducts a [Time On Target](https://en.wikipedia.org/wiki/Time_On_Target) bombardment. It fires at its furthest targets *first*, then closer and closer ones. The end result is every target is hit *simultaneously*. Nobody can see it coming. Nobody gets any warning. # How Do You Know Who You're Firing At? > > *Is there some way that a planet could defend against this* ***galactic scale*** *weapon of mass destruction*? > > > "Galactic scale" is a bit of a problem for your targeting. We're talking 100,000+ light years end-to-end. Being able to fire a relativistic kinetic projectile and hit a moving target 100,000 ly away is crazy complex and requires information you ***literally cannot have***. At the time of firing you'll be seeing your target as it was 100,000 years ago. While you can do rough calculations to determine its motion, you can't do this with sufficient accuracy to hit a planet both because of the crazy complicated and chaotic math involved, and because you cannot have sufficient detail at that range. You probably can't even see the planet. There's also the question of how you got into a fight with someone it takes 200,000 years to communicate with (100,000 years out, 100,000 years back). When your projectile falls, who will even be on that planet? Will it even be the same species? It's like firing at us for something the Neanderthals did. Either you're doing some extremely grand space opera, or you should scale it back. A lot. 20 light years offers you about 100 or so systems to play with and time scales that are inside a lifetime. # Do we even need a BFG? What if we put a motor on this 1000 kg mass? What would that take? Running the numbers we can use the [rocket equation](https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation) to find an ideal solution of how much reaction mass we'd need for a theoretically near perfect sci-fi space motor. $$m0 = m1\*e^{dv/ve}$$ * m0 = starting mass * m1 = final mass, 1000kg * dv = total change in velocity, 0.9c * ve = exhaust velocity The tech details don't matter because ultimately space motors throw mass out the back as fast as possible and rely on Newton's second law to be thrusted forward. It all depends on how much (reaction mass) and how fast (exhaust velocity) we throw it out the back. The higher the exhaust velocity the less mass we need. Less mass means a lighter spacecraft which requires less thrust for the same acceleration and the [Tyranny Of The Rocket Equation](https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html) works in our favor. The exhaust velocity of a very, very efficient ion thruster is 210km/s. So that's $1000kg \* e^{0.9c/210km/s}$ or $1000kg \* e^{1286}$. $e^{1286}$ is so large even Wolfram Alpha won't give me an answer. So much for known tech. If ve = 0.1c that's $1000kg \* e^9$, 8e6 kg or 8000 tonnes of reaction mass. Not infeasible! Probably about as much mass as your average sci-fi space cruiser. Let's go faster! Let's say we can throw mass out the back of this engine at ve = 0.9c! $1000kg \* e$ is a mere 1700 kg of reaction mass. Great! We're in business... maybe. What about the energies involved in throwing all this mass at relativistic velocities? How much mass are we throwing out the back and how much energy does it take? The mass is easy enough to calculate since we're at constant acceleration, $reaction mass / time$. How long do we need to be accelerating? Depends on how far the target it. The worst case is a nearby star system at about 4.5 ly. It's accelerating constantly to 0.9c, so the average projectile velocity is 0.45c. It'll be accelerating (hopefully) tiny fractions of this mass for roughly 10 years. If ve = 0.1c, that's $8e6 kg / 10 years$ or 25g/s. This is a lot. The kinetic energy of 25g at 0.1c is about 1.1e13 J. This is a lot of energy. This means our engine must produce 11 TW for 10 years: 3.2e21J. Assuming the most mass-efficient generator possible, a matter/anti-matter reaction, and using $e = mc^2$ and $m = e/c^2$ that would require 35,600 kg adding significantly to our projectile's mass and throwing off the rocket equation. ve = 0.1c won't cut it. If ve = the ludicrous 0.9c that's only $1700 kg / 10 years$ or 5.4mg/second. At 0.9 it has a kinetic energy of 6.3e11 J. That's still a lot of energy requiring 0.6 TW over 10 years: 2e20J or the matter/anti-matter reaction of over 2000 kg again throwing off our rocket equation, but not unrecoverably. I'm not sure on the math, but I'd estimate we'd wind up with something like 5000 kg of reaction mass and 5000 kg of matter/anti-matter. What about beaming it power from a laser? If you can focus a 1 TW laser on a moving target 5 light years away and sustain it for 10 years, why are you messing around with throwing rocks? Just cook them. As assuming we can come up with some lightweight matter/anti-matter power source, and a lightweight engine that can fire milligrams of matter at 0.9c, this can be done inside known physics... but not known engineering. [Answer] As Phillip said, this is viable for within-system warfare, but not for interstellar. **Accuracy is a major problem**. Even at relativistic speeds, projectile will take many years to reach another star system, so you need to predict where the planet will be then. You cannot adjust your aim as it will take years between shots, and your target will notice the near-misses, and find a way to detect and deflect or destroy further shots. You can try to install guidance system, but then you need to go slower than light to give it time to react, which also gives target time to respond. And it is a technical challenge to make a engine that is powerfull enough to alter trajectory, and robust enough to survive being shot from a railgun. If impact destroys the target planet, the **recoil will do major damage** to launch planet, or at least alter its orbit. You can use planet's own spin and orbital momentum to help accelerate the projectile, but those are a fraction of relativistic speeds. Impact is shorter than acceleration, but not by a whole lot (unless your railgun is miles and miles long). "firing a 1,000 ton bullet out of the **atmosphere at relativistic velocity**" will likely obliterate all surrounding area. Here is the a [10kg bullet being fired](http://www.highpants.net/wp-content/uploads/2014/04/Highpants-EM-Railgun-Results001a.jpg) But you could put your BFG on a moon without atmosphere. **Defense:** If it is coming at less than full speed of light, you can detect it. Then you hit it with your own impactor. It does not have to be heavy, 1T will do enough to deflect it, or destroy whatever guidance mechanism is there. If the projectile is coming at the speed of light, I am not sure if guidance system is viable, so defenders they can just alter the orbit of their planet slightly, in random direction, every few years. Your projectile takes more than a few years to get there, and the planet will be out of the way by then. Technology to alter the orbit will be similar to your BFG: launch heavy rocks. [Answer] You said in a comment that your universe has FTL travel and communication, while your railgun is firing sublight-speed projectiles. That makes it a useful weapon for interplanetary warfare, but not so much for interstellar warfare. It will take years to hit something in a neighbor star system and up to 100,000 years to hit a target at the other end of the galaxy. Military deterrent doesn't really work on those timescales. When the civilization living on the targeted planet gets the news that there is a RKV heading their way, they have plenty of time to slightly change the orbit of their planet so it will miss (which might not even be necessary if you forget to account for some unknown mass changing the target orbit or your projectile's trajectory), change its course by hitting it with their own relativistic mass or just relocate elsewhere. And they will likely leave this challenge to future generations while concentrating their current effort on retaliation against you. [Answer] There are so many reasons this won't work I'm not sure if I'll be able to list all, but let's give it a try: # Space is big, part 1 Passive missile has big flaw. Little errors on the launch can change into big ones at the target. And we are talking interstellar distances. Radius of planetary orbit is negligible compared to distance traveled. Radius of a planet does not even count. # Space is big, part 2 Three body problem is not solved analitycally yet, and probably will never be — it was proven impossible within our current understanding of mathematics. This means you need to calculate effect of each gravitational mass on your missile, and on each other. Each asteroid that can pull it even so slightly sideways. Each tiny impact. This is a lot of numerical calculations. And lot of numerical errors. And a lot of things you will have to measure, a lot of measurement errors. On the interstellar distance it will make it miss. # Countermeasures are easy All you need to do is to hit it slightly, a little from the side. You have years to prepare, decades maybe, because impacts with interstellar gas will release detectable amounts of energy. If you have FTL means of knowing it is coming, you have literally dozens of millennia. You can retry few times. Side of missile will explode, rest will fly on different course. # Retaliation If such missiles could hit, you can be pretty sure that firing one will result in revenge launch. Use one and you are playing with mutual kill. Or, with FTL, they can prepare some nasty surprises for your descendants and make *them* stop the missile or die,with thousands of years to try and stop it on their own if this fails. [Answer] > > wouldn’t this mean that this gun could destroy any planet in the galaxy if given enough time and accurate information about said planet’s orbit? > > > No, because there's a vast amount of space which is *completely* inaccessible from the BFG. For example, in this image, only that area of space in which the *w*-axis has positive values are visible. The planet rotates, so other parts of the Universe become visible as others are shielded by the planet, but there are still huge swaths that will never be visible. For this same reason, the only people in the Northern Hemisphere who can see southern stars are those very near the Equator. For guns on the equator: visualize what the "tangent plane" would look like, rotating around the planet. (As an example, inflate a beach ball, and then slap a piece of cardboard at the equator.) There's no way that it can hit anything around the Poles. [![](https://i.stack.imgur.com/hPosy.png)](https://i.stack.imgur.com/hPosy.png) [Answer] Space is huge (as other answers have stated) and it's also tremendously unknown. Remember that a 0.000000001% degree error on these calculations with a projectile travelling 1000 light years @ light speed will miss by a few million km. The calculations required for this multi-year weapon to strike a target must include: * Projectile can't hit where the planet is now, it needs to project where the target planet will be when the strike occurs. Anything that effects the motion of your projectile could also effect the target. * Gravitational effects of all bodies the weapon (and your target) might pass. Remember those bodies that could gravitational effect the bullet are also in motion, so you'll need to know each bodies movement along the path to know where they will be when they interact with the projectile. Remember these factors will also affect the position of your target. * Space weather. The Heliosphere protects most of the solar system from some interesting weather that we barely get a glimpse of on Earth...but there is matter travelling in all sorts of directions at near speeds of light that will be knocking your projectile around. Not a major amount by any measure, but it doesn't need to change the trajectory much to cause a miss. I'd be curious what would happen if your speed of light projectile hit a proton travelling at nearly the speed of light in the opposite direction...I'm sure the people at CERN would like to know, and I'd speculate it'd be enough to adjust the trajectory of your bullet. * Dark Matter. What is big and unknown, and able to impact the trajectory of your bullet? You would need a nearly omniscient level of knowledge to strike a target at that range. [Answer] Suppose you describe WW1 16" gun to a civilization that has bows and arrows. They say "what if picked one up and shot it at a mammoth?" This seems to be your problem here. The energy involved in pushing 1000T up to a decent fraction of c means you aren't doing it *on* an inhabited planet. The energy budgets are wrong for that. That kind of weapon isn't mounted on an inhabited planet. Similarly, a 16" gun isn't something you carry around. Using this weapon on a civilization that isn't on a similar energy level is like using a 16" gun on a mammoth. Sure you kill it, but why are you using a 16" gun to kill a mammoth? Mammoth's *aren't dangerous* to someone with 16" gun technology, and anything of value will be destroyed by using it. It is ridiculous overkill. Your weapon could probably hit a planet within a few light years, assuming you solve the aiming problem, but beyond that the travel time is long enough that chaos in planetary orbits and gravitational tug on the projectile will make the target not be where your bullet is. We used 16" guns in WWI to destroy fortifications designed to defeat 1800s military guns. If this weapon is built, you'd use it in a similar sense, to defeat something a slightly lower tier of technology cannot defeat. Quite possibly you wouldn't shoot solid projectiles, or you'd somehow mount guidance systems. It wouldn't be on a planet. Maybe it would be a set of solar-sail based accellerators which in turn are moved around by ridiculously high energy lasers mounted on other platforms. Each shot might involve gigatonnes of mirrors blasted off to infinity and the entire solar system lighting up with reflected laser light. The weapon you describe is a type 1.5 civilization weapon. At relativistic speeds, the KE of matter is approximetally its rest mass. Type II civilizations have 4E26 Watts of power. A Type I civilization could fire one every 26 days using the entire civilization power output. A Type II civilization can fire something like that a few 1000s of times per second. A Type 1.5 civilization could fire one using 22 seconds of civilization power budget. Storing 26 days of your civilizations' power budget is unreasonable; Tsar Bomba is about 3 hours of our civilizations' power budget. A Type 1.5-2 civilization isn't planet-bound; no significant fraction of their economy is in a Earth-depth gravity well. This is simply a side effect of heat budgets (their energy budget is too large for an Earth-sized planet to handle). Type 1.5 might be able to have a significant fraction of their economy in a Jupiter-sized body, but by Type 2 that isn't reasonable (other than having disassembled Jupiter-sized bodies for raw materials). [Answer] Putting inside an atmosphere will cut one of its balls off. Lobbing your bullet out of the atmosphere, it will start to burn up. It will also add some imprecision - as it passes through wind, clouds and turbulence, its course will change. Not a lot, but it's got a *long* way to go. It could also damage the planet, and certainly the colony. How loud is the boom? It would be really hard to hit things that it can't see in the sky - a ship on the other side of the planet, for example. [Answer] This is somewhat more of a comment than an answer, but the closest thing to a worked example was in the book "[The Millennial Project: Colonizing the Galaxy in Eight Easy Steps](https://www.amazon.ca/Millennial-Project-Colonizing-Galaxy-Eight/dp/0316771635)" by Marshall T. Savage. Near the end of the book, he speaks of a galaxy spanning civilization using massive mass drivers to send pods between star systems at .9 *c* in order to maintain trade and communications between the various star systems (with "reasonable" time delays, especially for a traveller inside the pod). The traveller is encased in some sort of gel or fluid since they will be undergoing about 10 g acceleration for a month in a mass driver which spans a large fraction of the *solar system* In the book, a similar device in the receiving solar system is used to decelerate the pods, and to launch a return pod. This may not be entirely practical since it is such a huge construct, and waiting for things to line up to fire the shot will also take a great deal of time. Unlike many of the other commenters, I do believe that this is a viable system, since the pod (or warhead) can be outfitted with a guidance system and is large enough for thrusters to provide the fine tuning of the orbit needed to strike a planet. Moving at .9 *c* it is coming very close behind its own light cone, so the target has very little real warning or time to deploy any countermeasures. Increasing the energy density at the launch end cam push the pod to almost any arbitrary speed, at .99 *c* you likely do have a planet buster, and the warning time is virtually nil. Needless to say, ownership of such device will be strongly opposed by everyone in the vicinity, and the knowledge that such a thing exists will be seen as an existential threat by almost any civilization in range. The likely response is to not just build a counter weapon in your solar system, but to preemptively carry out a first strike to neutralize the threat. [Answer] A giant space bullet is never going to be able to hit a random planet somewhere in the galaxy. Even assuming you could build such a weapon, the slightest micrometeor or gravity wave would knock it off course enough to miss the whole solar system. Imagine a sniper hitting a nickle two miles away in a class five hurricane only harder. Anything like this would have to have a guidance system. If you have a guidance system, you might as well stick and engine on it and have it fire itself in space AKA a kamikaze spaceship or guided asteroid. Finally is the time frame. Star systems are light years apart. When you fire the bullet, you'll be wiping out anything from the target's grandchildren to hitting a dead planet because the race already went extinct. Giant space bullets will never be a cross galaxy threat. [Answer] There are many very cheap deterrents to that weapon. Some space federation or whatever equivalent to a country there is in that fictional world may simply shoot a very powerful laser at the cannon. Just melt a few millimeters off of it, and the whole thing will explode the next time it fires. If the cannon is very articulate, you can move a few Phobos-sized asteroids onto the orbit of the planet. Should a projectile hit one of these asteroids on its way through a target, not only will it be deflected, you will also end up spreading a lot of large-sized particles in orbit. This will ❤❤❤❤ artificial satellites, space stations and ships that get hit by the particles. Say goodbye to all your space efforts and forces. [Answer] In addition to the other answers, it's worth noting yet another reason the weapon should not be launched from the atmosphere. Not only will it be inaccurate and slow down, but Randall Munroe of XKCD fame can give some insight on a new problem: > > 3,000 kilometers per second = 0.01c: > > > This would be pretty bad. The thing that makes this a little unpredictable is the fact that at speeds in the range of hundreds of kilometers per second, the air [begins to undergo nuclear fusion](http://www.sciencedirect.com/science/article/pii/0032063389900305) (Google that paper title to find the full text). This, combined with plain old plasma heating, may manage to eat apart the diamond sphere completely before it reaches the ground. > > > In this quote he's talking about a 100-foot meteor; it would start to break apart, but even if your big bullet doesn't stay together, most of the kinetic energy will still hit the target planet. The real problem here is the fusion part. There's a LOT of air in the way of a typical launch, and at relativistic speeds (keep in mind the example given is for only **0.01c!**) this would cause the meteor to travel upwards through the atmosphere, causing fusion of certain compounds in the air it encounters on its way. You know what else causes fusion? Thermonuclear bombs. TL;DR: Put it on a moon or something, as suggested elsewhere. ]
[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/134475/edit). Closed 5 years ago. [Improve this question](/posts/134475/edit) One of my POV characters in this epic fantasy is a slave. He and another slave get sent on a mission to another nation by a slave master (who is evil). I'm struggling to find a way for these slaves to actually take part in this mission instead of having them run away. The reason can be magical or just something smart, I haven't finished making my magic system yet so I'll be happy to change something around too. I' m looking for some reason they will comply and put their master's plans into action. My slave was sold into slavery by his family who are rich. The custom in my world allows for a family to sell up to three children into slavery if they disappoint the family. Kind of like being shunned, but worse. [Answer] All the slave are induced into drug addiction, and the master is the only one to have that drug. If you know the [legend of the Assassin](https://en.wikipedia.org/wiki/Assassins#Legends_and_folklore), you should better understand what I am talking about > > The legends of the Assassins had much to do with the training and instruction of Nizari fida'is, famed for their public missions during which they often gave their lives to eliminate adversaries. Historians have contributed to the tales of fida'is being fed with hashish as part of their training. > > > No matter how evil is the master, the drug dependency will ensure that the slaves return to him. [Answer] You don’t need magic or any other fantasy element; standard coercion techniques will work just fine. The slaves have families. The master keeps their families under his control, and warns the slaves that those families will suffer if the slaves do not return. [Answer] Some IRL solutions. Every slave can run away. And every slave will be hunted, dragged back to his master, tortured publicly in front of other slaves and then killed. With a reminder that everyone who will try to run will face the same consequences. Dying a gruesome death is worse than living a bad life. Extra if the slave have new "slave family", usually forced by slave masters (to have free new slaves) that can be held hostage. Magic solution - not a single slave is given a task to do on their own without an overseer. And slave is marked with a "slave" insignia that can be bounded with a bracelet that overseer wear. On that bracelet you can see each slave "mark" if it's not touched by bearer after head counting the magic will kill the slave. Also the bracelet has build in recognition if the bearer is alive and is it really the one who should be touching the marks. [Answer] For much of history slavery was often better than the alternative. Keep in mind slavery for much of history was not the slavery we think of when we hear the word, the line between slave and serf got pretty gray. Slaves often had rights or protections and usually had the possibility to become free with full legal rights. Slavery was often a temporary situation often a way to pay of a debt, even when it was not it was far better than the alternative. A slave who runs away is a criminal thus an outcast without any legal protections, with no land, property, or money, with no ability to feed themselves, an outcast might not even be able to buy things even if they had money. Just being a outcast can get you killed for most of human history. You are easy prey for bandits, even normal people were allowed to rob or murder you with no repercussions, you had no land or porperty, and you will tend to starve in the winter/dry season. A high value slave on the other hand would often live much better than the average free man. They could earn money, own property, gain status and influence, even buy their freedom. Alternatively in rome for instance a runaway slave would be executed or branded thus becoming the lowest form of slave labor often miners or other such dangerous and deadly works were their lives would be short and brutal. The sad truth is for much of history being a slave was better than being an outcast or criminal. People without the protection of society did not live very long, better to be a temporary slave than a permanent corpse. [Answer] They comply and even return because, to their knowledge, their master is the only person that has the antidote to the disease that forces them to obey. They may see the disease as a curse, but in practice it could be a distant relative of a cross between the zombie ant fungus [[1](https://en.wikipedia.org/wiki/Ophiocordyceps_unilateralis)] and the rabies virus [[2](https://en.wikipedia.org/wiki/Rabies)]. This disease acts on the neural system of the hosts and makes them susceptible to execute orders given during the early stages of the infection. After a certain short amount of time, the host becomes immune to following other orders, and will not be able to conceive the idea of disregarding the initial commands. As the disease progresses the hosts begin to show signs of degradation of mental faculties, which could also be accompanied by fits of excruciating pain, short bursts of fever, and other temporarily debilitating symptoms. After a long enough period, they turn into mindless zombies, unless the antidote is provided, which completely clears the disease and its effects. The master is a regular user of the antidote, hence the immunity. Also, if the slave turns into a zombie, the infection could become contagious, with added flare for a pandemic twist. [Answer] Some sort of magical addiction? Slaves spending too long away from their master get ill - perhaps they need to periodically take a special potion that the master charges with their own magic. For a long-distance mission, the master can provide a small supply of the potion - enough to get there and back - but without the Master's magic they can't make more. A potion made by anyone else would also not alleviate the symptoms. Transferring a Slave from one Master to another would then involve "resetting" the Slavery Curse to register the new Master's magic instead of the old one, but can only be done by the heads of the local Slave Auction Houses. (This would also mean that Slaves could act as an insurance against Imposters attempting to usurp someone's position via transformation or disguise magic - giving a non-Evil reason why some of your rich/powerful "Good Guys" would keep well-treated Slaves as a Seneschal or something. For the child of a lowly farm-worker, such a position could actually mean they move *up* the social scale by becoming a Slave.) (There may be rumours of other people able to break or retarget the curse, that runaway Slaves try to find - but many of those trails lead back to Bounty Hunters making a living by capturing and returning escaped Slaves...) [Answer] ## Lies The master feeds slaves a steady diet of lies throughout the time that they are with him. The lies convince the slaves that *all authorities* are awful, that *nobody* is to be trusted, that the objects of freedom are *insidiously bad*, and that other slaves who left before *suffer*. They may believe that outsiders are inferior or dangerous, or even perhaps that outsiders aren't real people. This is made easier if the master's household has some key difference from the rest of the country; perhaps all food is prepared raw, or everybody speaks with an distinct dialect. ## Stockholm Syndrome Stockholm Syndrome is what it's called when the oppressed feel strongly loyal to their oppressors. It could be cultivated by developing a co-dependent relationship directly with slaves, in which slaves feel emotionally tied to the master, i.e. they would fear that their absence would result in the master's harm... ...or it could be cultivated by abuse, in which the master harms the slaves and convinces them that it's their fault. The slave who believes this will find it morally fraught to go somewhere where he isn't getting his proper punishment. [Answer] Perhaps the problem could be solved from a law-enforcement perspective if your country has good policing and the slaves are clearly (and irreversibly) marked. The order to the slaves might be communicated to the local authority together with the slave's IDs and some payment for administrative costs, and once the slaves leave they are free to roam. Should they be spotted by government officers, they could be checked with the list off current slaves in action, and the master notified of their location and condition. Should the master notify the authorities that they should return, they will be captured and returned to the master. Should they be found outside of their assigned region, they will be taken into custody and the mater will be notified. This could add some tension to your story, just by the fact that there is that *slim* change that they might escape, if they're smart and nimble enough. You could also add some close encounters and such to build up moments of tension in a classic "we are hunted" style. It is a highly flexible solution and could also provide more opportunities to share the intricacies of your world, by allowing the slaves to wander a little more and get caught up in the travel, rather than being mind-controlled from point A to point B. I hope this answer may bring you some inspiration. [Answer] Magic is allowed? Then it's easy: The Master places a curse on the slave. It will trigger after X hours and get stronger over time. The curse overrides all other wishes the slave might have. Until eventually the only "goal" the slave wants to achieve is getting home to his master. In its final form this will override all other desires, eating, sleeping, drinking. So if the slave does not get back to satisfy the curse's wish, he will die a cruel self-inflicted death, e.g. by walking through the desert without enough water. This has the benefit over an addiction that it cannot be satisfied elsewhere and that the drug does not need to be supplied beforehand and afterwards. [Answer] For this answer I'm assuming this master is either a wizard or has mage under him (powerful enough to do what I'm about to propose). To ensure the compliance of the slaves in such a situation, the master steals something of value from them. This something, however, is not a trinket or a loved one, but something ephemeral, intangible. Suppose you could steal laughter or joy. Imagine not being able to sleep or dream of better days. Just think of someone that can rob you of love (the actual emotion) you have for your soon to be wife (whom is also one of the master's slaves). I don't know about you, but if someone stole my ability to perceive humor or to have hope, I would cover great lengths to get it back. [Answer] Magical Solutions: - The master has the heart (soul) of the slave and can torcher or even kill the slave with this. This isn't really supported by a structural magic system (with elements), but by an skill system (someone just has the skill to do so) - The magic language binds someone to the vows done in this language, like in [The Inheritance Cycle](https://en.wikipedia.org/wiki/Inheritance_Cycle) [Answer] What about branding? It doesn't require magic, and that way they'll be recognized as slaves by citizens and authority figures can figures. Those people can figure out who owns those slaves and turn them in for a reward. The master would give the slaves written permission to go out to complete a task which will prevent anyone from falsely accusing them of desertion. The branding will add an extra challenge to players insistent on escaping slavery by hiding the brand or rebranding themselves. [Answer] # Non-Magic * **Coercion:** The slaves might have a family. The master can use the family as a coercive tool. If they don't return, their families die / get tortured forever. * **Power:** The slaves know that their master is really powerful. Even running away the master will find them, capture them... and make them regret. The master has a lot of man and allies to accomplish its task. # Magic Allowing magic makes everything really easy. * If you think of running away or do it: you are punished. * If you don't come back / accomplish the task in X days: you are punished. **Punishment** can be something like asphyxia until regret, cardiac arrest, dead, constant pain that increases over time, sickness, loose of memories (family and childhood), emotions (love, happiness, joy), abilities (see, hear, walk, feel pleasure or joy, eat, sleep). [Answer] **Magic:** Remove the heart of the slave and keep it on a jar. Heart is preserved and still running, as long as the body also does. If they do not return or behalve in a way that you don't like --> destroy the heart and the slave dies. If something happens and the slave dies for other reasons --> you will instantly know. BONUS IDEA 1: the slaves do not know this until some of them die abruptly. BONUS IDEA 2: Master can detect when the heart is stopped or working hard, and act on consequence --> shock after a hearth attack, etc [Answer] Similar to John's answer. Suppose the person is clearly marked as a probably slave (for example, skin color). Even if they *aren't* a slave, they are liable to be kidnapped and sold into slavery by unscrupulous persons. Their master, however, is a good master and treats them more as employees than slaves; i.e. they are slaves primarily in name only. If they escape, they are liable to be sold somewhere else, while if they show they are a slave, they are protected by their master; in addition, they are able to stay with their loved ones in reasonable safety. As an example, Joe Slaveholder sends his slave on a job. A) John Slave can run away and perhaps be captured by Jonas Slavetrader and sold somewhere else, or brought back and risk being sold by Joe. B) John Slave can do is mission under his owner's protection (if he is mistreated, his owner can use his authority to deal with it), and come back to his family with perhaps even more trust and freedom than before for being trustworthy. C) Any variation between A and B; likely results in lost trust and freedom. ]
[Question] [ In my story shapeshifting drugs are controlled and only widely used for therapeutic medical purposes only, a recent study showed a young patient with severe depression and poor appetite is suddenly craving for Taco after turning into a sea sponge and another similar report of a grandma suffering from ADHD signs up for bonsai lessons soon after turning into a shoebill. Lately there has been an increase in the demands for time released shapeshifting drug which can cost up to hundred times of those immediate or fast acting ones, ironically clinical trials have repeatedly shown that the shapeshifting drug is just as effective as those in the control group whom are hooked up to a virtual reality headset. So it is not the drug but then why many honest doctors still prescribe costly time released shapeshifting drug over those safe and equally potent fast acting ones? Say a pair of twin Alice and Bob, each took a time released shapeshifting drug and a fast acting shapeshifting drug respectively, Alice would have to walk her twin, now a labrador retriever at a nearby park for no more than 12 hours while waiting for her side effect to kick in. If the side effects of both drugs are exactly the same then why the costly time released shapeshifting drug is more popular than fast acting ones? [Answer] **The cheap one doesn't last as long.** You want a quick rush of being a falcon for a few hours? You can just go for the cheap one - but you run the risk of it wearing off unexpectedly at an inopportune time, like say, 5000 feet in the air. You want to keep it going longer? Use the slow-acting one. Not only does it last longer, but you can easily feel when it's starting to wear off and get somewhere safe before you end up transforming back without warning (and in this case, plummeting to your death). [Answer] Maybe the long-length one is less painful to use. I can only assume that you'd feel something while the transformation happens. And if that is spread out over a longer amount of time, it won't be as sudden, and won't be as strange-feeling. As a side note, it might not be pain, but some other thing. Maybe like it is when you've sat down without moving for way too long, and then move. That vibrating feeling. [Answer] # The rush! This might just be out of scope. Changing shape goes along with more psychological effects. Though clinically the same in some respects, the rush you get from being in two forms at once as you slowly transform is exhilarating. The fast acting can be scary and uncomfortable. As the effect comes from experience and not directly from the drug it isn't a side effect exactly. Imagine it as a go-kart drive. Normally it's exciting if you do it for 10-30 minutes. If you then cram that whole experience in 1 to 30 seconds it'll be experienced quite differently. [Answer] Your brain takes time to adjust to a change, days to weeks. The fast-acting one leaves you confused and afraid as your brain can't keep up with the radical changes. The slow acting one gives you time to adjust to the changes. Also, rapid changes will be very unpleasant even if your brain somehow adjusts. It takes enormous amounts of energy so you would need to be fed intravenusly to make sure you dont die from starvation. It also makes your hormones go haywire as the hormones of both species intertwine in quick succession rather than slowly build off one hormone while building up the other one. You will likely feel nauseous, famished, thirsty, disoriented and dizzy. [Answer] The treatment isn't just one drug, but a suite of related drugs that have to be carefully tailored to the target user and the intended shapeshifting form to ensure nothing goes wrong. This means that it's typically administered at a clinic rather than used at home. For the time-release version of the treatment this isn't a problem. The technicians can mix up a cocktail that takes effect a predictable time later. You might go to the clinic in the morning and then have the drugs kick in after a few hours when you're at home or wherever else you intend to enjoy your shapeshifting 'trip'. Maybe it will occur a few minutes earlier or later, but it's close enough to make plans around. The quick onset version, in contrast, takes effect quickly and unpredictably. It might be almost instantaneous, or it might strike after a few minutes during the car/bus ride home, which would be quite inconvenient for everyone. So while the drug course itself is more expensive, it's much more convenient and safer, and it's not more expensive than going to a clinic with its own dedicated animal park attached to it. [Answer] Use of shapeshifting drug is regulated in certain locations, and if one is found in possession of the substance, is not admitted. The drug is hardly concealable before its assumption, so hoping to smuggle one in and then take it's not possible. On the other hand, detecting the drug once assumed is also impossible. Therefore the slow acting drug allows one to take the drug, enter those locations and then shapeshift, with very few chances of being caught. [Answer] **Marketing and FDA.** The slow drug is marketed to doctors. Its the one who has put in the money and effort to be approved for medical use (The fast version is marketed only for recreational use). Its got an easier name to remember. If doctors prescribe the fast version, they would have to jump through all sorts of paperwork hoops. The hospital pharmacy probably doesn't even have the fast drug. (The doctors never prescribe it, so the pharmacists never stock it, so the doctors never prescribe it) They aren't paying. The patient isn't paying. The insurance company is paying. The slow drug has been fully approved. The insurance legally has to pay for it. The fast drug hasn't been approved, so the insurance can refuse to pay for it if they want. (As a general principle, the insurance don't pay for anything if they can avoid it) This is exactly the sort of thing that happens in real hospitals according to slatestarcodex. [Answer] **Advertising.** The fast acting shapeshifting drug has been around a long time. It goes by its generic name. It is considered sort of déclassé. Poor people with safety net insurance can get it. Yes it works fine but it is so 3 decades ago. The new sustained release has got a sweet brand name - maybe something like "Flyvanse" or "Tryvanse". Ad campaigns and persuasive drug reps work on the honest docs and persuade them that the new thing is better for their high end fancy patients. And so the new stuff that is the equal of the old stuff but 10x the cost gets prescribed. Capitalism! [Answer] ## Vanity Do you want to look muscled for 10 minutes, or for a long time? That nice wavy hair, firm booty, slightly muscled figure that attracks potential mates... ...would be a shame if that wore off. So you need it long term ]
[Question] [ What digit, if removed, would hamper a human from fighting using medieval weaponry? (I'm toying with both thumbs but this may be too limiting in the work that the slaves can do or both little fingers as I believe they are important for grip.) See below for more context: A humanoid race in a typical fantasy setting with roughly medieval technology keeps humans as slaves. They view them as little better then vermin and to reduce the effectiveness of any uprising they "dock" or remove a digit from both hands. Thank you for your time in reading. [Answer] As a person who studies European Martial Arts, I feel qualified to answer this question. It's rather morbid, but swordsmen also lost a lot of fingers, too. It just so happens that getting hit in the fingers is a realistic risk when fighting without full basket-hilted weapons! # You Cannot Remove a Digit without Removing Utility There is an unfortunate dependency upon hands for both manual labor (the word "manual" comes from "manus," meaning *hand*) and fighting. Simply, the capacity for a person to use a farm tool and a weapon rely on the same fingers. Remove a finger and both fighting ability and manual labor ability decrease. # The Thumb and Index Fingers: Too Much Cutting off a thumb simply makes most tools totally unusable. Maybe they can pick up *some* rocks and bash with that, or throw punches, but don't expect proficient use of most weapons. Likewise, the index finger is too important to most tool use to remove. It may remove too much grip strength to let people use polearms or swords effectively, but also farming implements and most manual trade tools. It simply removes too much value! # Pinky or Ring: Not Enough These can be used for subtle changes in grip, changing the weapons position enough to be a consideration while fighting. This becomes important when binding and winding: controlling the opponents blades when in contact with your own. As you may guess, this doesn't prevent someone from taking a threshing flail, stealing a sword, or taking their fruit-harvesting bill hook and smashing another person in a violent slave revolt. The use of these fingers *is important* but *not crippling enough,* especially to the untrained individual! # The Middle Finger: Likely Best Choice Legend has it that the French would remove this finger (and in some versions, also the index finger) from English archers so they could not draw their bows. Thus the rude gesture of "flipping the bird," developed so those English could show those Frenchies that they're not yet beaten and have better missile weapons. [It's a myth](https://en.m.wikipedia.org/wiki/The_finger#Classical_era), but maybe slaves of this world can use a similar gesture as mild defiance of their masters. Anyways, removing this finger does decrease grip strength and prevents some sword grips. Specifically "fingering the guard," which gives a fair amount of control on the point. This is actually a big step in how we get things like the "pistol grip" for modern fencing and basket hilts. Additionally, this finger helps significantly with grip strength, though not as much as the index finger. So you could expect them to be able to handle tools but not take the rigours of blocking an incoming weapon and fancier fighting techniques. [Answer] ## Slave Rebellions Always Fail I can not emphasize enough how often they fail. In the thousands of years of human history where the majority of civilizations employed large scale slave populations, a slave rebellion has literally never won a total military victory and secured themselves as a sovereign nation all on thier own. The very few successful slave insurrections such as the Haitian Rebellion were only won with the heavy support of foreign military and logistical aid. A lot of this boils down to how big of a difference proper weapons, armor, training, and tactics makes. Boudica's Revolt is a good example of this. While Boudica's army was estimated to be at least 8 times as large as the Roman army, her rebellion was still a total failure. The big issue was that most of her army was just peasants sent to the battle field with whatever improvised weapons they could muster. The issue with sending poorly trained and equipped troops into battle is that most individual soldiers care if the battle will be won or lost a lot less than they care if they will survive said battle. When the superior Roman weapons and training led to the decimation of Boudica's first few lines of troops, the guys next in line saw how badly they were losing and tried to run. As they broke, the guys behind them saw things were not going well so most of them tried to run too. Those who may have been brave enough to stand and fight were no longer in a proper battle formation, making them easy to isolate and kill. This sort of panic is called a rout, and is the real winner of ancient and medieval battles way more so than just fighting until all the enemies are dead. The routed army suffered 80,000 casualties as Roman soldiers and cavalry chased down the panicked rebels. In all, Rome only lost 400 men. The difference in quality of arms and training between an army and slave tools only grew larger in the Medieval period. For a slave to even hope to beat an army fielding armored knights and men-at-arms, they needed weapons and tactical knowledge that they generally did not have. The longest improvised pole-arm a slave could muster would be farming implements no more than 4-6 feet in length, and they would have known nothing about pike blocks or phalanx tactics to even know that they needed more. They would very rarely have any access to shields, armor, or bows of any sort, and a knights lance was typically 10-15ft long such that knights could just charge down rebel slaves with impunity, shoot them down with bows, or dismount and decimate them using shield wall tactics. All this said, there was one weapon easy enough for slaves to secretly make a lot of that could threaten a mediaeval army: the sling. A sling can be fashioned easily from found scraps in what little free time a slave may have, it can be hidden very easily, and trained with quietly. On top of that, slings are excellent weapons against armored enemies. The Romans for example actually preferred slings over bows as weapons of war because the impact of a sling could kill a person from internal injuries, even when the actual stone failed to penetrate the armor. While a bunch of poorly trained slaves with slings may still not be able to beat a professional army of archers, pikemen, and cavalry, they will still be able to inflict enough heavy casualties to make their masters understand that the sling is the most dangerous of all slave weapons. ## Why removing fingers does not work In the Medieval period, the French would allegedly cut off or cripple the ring and middle fingers of captured English archers to prevent them from ever using a bow again, but crippling a slinger is much harder. When using a string, you typically pinch the release string between the index finger and thumb, and the stay string is either looped on the middle finger or pinched by the lower 3 fingers... however, typical is not the same as the being the only way to do it. Longbows had very high draw weights that made them pretty much unusable with the weaker lower fingers, but slings don't put nearly so much stress on the hand for equivalent stopping power. If you remove the index and middle finger, they can just loop the pinky and pinch the thumb to ring finger... in fact, with a bit of ingenuity, a sling can be used even with any 4 fingers missing. Cutting the fingers off of a rebellious slave actually reduces his options for what weapons he can wield directing him towards the dangerous sling. For a slaver, it is in many ways better to let a slave have all 5 fingers, and to cut him down when he tries to fight you with a pitchfork, than it is to cut off fingers forcing him to consider his other options. This is before you even consider how much missing fingers devalues your slaves. Also, dismembering your slaves as a matter of policy is a good way to trigger a rebellion, not prevent one. If a slave thinks he can have a tolerable life by doing what he is told, then he's a lot more likely to be compliant than if he knows he will be maimed either way. Using violence to control people only works when you leave some hope that they have the means to avoid that violence by submitting to your control. [Answer] Counter suggestion: **Removing their Tongues** Okay, granted your question called for Fingers, but allow me to present the alternate proposal - Removing their Tongues. Without a Tongue, they cannot speak. Medieval type slaves I think we can presume cannot read or write. **Without a means to communicate effectively between themselves, it's much much harder to organize a rebellion** Now - for your framing - removing a tongue doesn't stop them from doing hard work - it doesn't stop the Slave from being given orders 'Do this, Do that, do this like so', nor does it prevent the slave from acknowledging an Order (e.g. nodding) - but it removes the Slaves ability to *talk* amongst themselves, without that organizing a complex thing like a Rebellion becomes almost impossible. Plus, you get to through in a little speciesism about how 'they don't want to listen to that innane human babble they call 'talking' [Answer] Frame challenge: based on historical examples, not even cutting both hands is sufficient to prevent uprising and usage of weapons. Let me introduce [Galvarino](https://en.wikipedia.org/wiki/Galvarino): > > Galvarino (died c. November 30, 1557) was a famous Mapuche warrior during the majority of the early part of the Arauco War. He fought and was taken prisoner along with one hundred and fifty other Mapuche, in the Battle of Lagunillas against governor García Hurtado de Mendoza. As punishment for insurrection, some of these prisoners were condemned to amputation of their right hand and nose, while others such as Galvarino had both hands cut off. Galvarino and the rest were then released as a lesson and warning for the rest of the Mapuche. > > > When returning to the Mapuche he appeared before Caupolicán and the council of war, showing them his mutilations, crying out for justice and a greater rising of the Mapuche against this Spanish invader like the one of Lautaro. For his bravery and gallantry he was named by the council to command a squadron. With knives fastened on both mutilated wrists replacing his hands he fought next to Caupolicán in the following campaign until the Battle of Millarapue where his squadron fought against that of governor Mendoza himself where he was able to strike down the number two in command. > > > As the saying goes > > Corner a dog in a dead-end street and it will turn and bite > > > [Answer] ## Are testicles 'digits'? Removing testicles lowers your male slaves' aggression, competitiveness, strength and dexterity. That's useful for preventing rebellion. Not so good for heavy labour, though. [Answer] **The Toe** The digit that keeps a human being from running away without declining their productivity for menial tasks is the toe. This type of mutilation was practiced commonly in America. (See links 1 and 2.) Since balancing becomes difficulty, and running impossible, this effectively diminishes the fighting capability of a human being. **Alternative: Ears** Historically, removing ears were also a common mutilation practice in European slavery in the Americas. (3) This is also part of the American slavery culture, disfiguring the face is another way to mutilate a human without impacting their productivity, and value to their owner - it's somewhere in the book in the fourth link. While this would not change a human's ability to fight, it would impact the social standing and probably impact their ability to form connections and networks, which is crucial for organizing resistance. **Addition: Does Mutilation Always Decrease the Value of a Slave?** Mutilation is undesirable to the human being that is mutilated, but not necessarily undesirable to the owner of the said human. The value of a slave whose genitals were removed would be twice the original on average in the Ottoman Empire. (I cannot remember the specifics, but the author is going to be either Halil İnalcık or Şevket Pamuk.) Here are some relevant links: * <https://www.quora.com/How-did-a-slave-owner-keep-his-slaves-from-running-away?share=1> * <https://listverse.com/2020/03/01/top-10-horrible-punishments-for-slaves-in-america/> * <https://www.jstor.org/stable/3789424> * <https://books.google.ca/books?hl=en&lr=&id=lGZNiCFBCZEC&oi=fnd&pg=PP7&dq=slavery+mutilation+antebellum+toes&ots=jWwzEoup5I&sig=UMVhBDEBxXgnv185te6vH9g-U6E&redir_esc=y#v=onepage&q=toes&f=false> [Answer] Slaves are not very dangerous. Taking away swords and spears is the best way to prevent slace uprisings. This is the most efficient, because it comparatively, not having a decent weapon is a much larger gap than being crippled in some way. That's just how big a difference good weapons make. Not only that, but crippling a slave will also make him less useful. Typically, only highly specialized slaves were crippled in some way. Think harem guards being castrated, certain types of craftsmen having their tongues cut out, or being made lame so they couldn't flee, that sort of thing. and they were all to prevent personal betrayal, not to prevent general rebellion. (Also remember that while these specialist slaves were still property, and so it was immoral, they also typically lived much better lives than the average freeman, so such positions were often competed for, inspire of the crippling. History is fucked up) More general slaves like the type we usually think of weren't worth the effort. If a slave master thinks they will revolt, he will just kill them. The whole point of general labor slaves is usually something to do with undesirables. Like the modern prison system, it's a place to send people who you aren't comfortable letting roam free. Running an economy on slavery is actually not very common, and not very effective either. Slavery is usually a way to keep specialist workers, or a dumping spot for people who the power structure doesn't want to be free to do other things. In the bronze age, it was typically both. Only a couple cultures tried to use slaves as the main labor force, and all of them regretted it. not because the slaves revolted, but because they just make a very poor base work force. What? People who do not benefit from a society are not very motivated to cultivate it? If only someone could have foreseen this! [Answer] # Big and or Pinky Toe These toes are crucial to maintain ones balance. Given wielding a weapon and practicing martial arts both require a strong sense of balance people without such features would have an inherent disadvantage. Also consider damaging the vestibular system in the ear. ]
[Question] [ Set in near future, the human and robot coexist together amicably and conflict is rare. They are designed to resemble us as close as possible for our sake, so we feel at ease and less paranoid by their presence. Even their behavior and speech pattern feels personal and genuine especially those micro facial expressions that doesn't create the uncanny valley effect commonly found in dolls, but one thing stands out like a sore thumb. They appears to sit on chairs designed for human! They are equipped with powerful hydraulic legs and sitting on a chair would stress the actuators for 2 reasons, first their body is very heavy and can easily break the chair with their full weight so they need to engage the actuators to support most of their weight and number 2 is the center of gravity is much higher for them because of the heavy battery pack located inside their chest and balancing it put more stress on the actuators. So despite all the trouble why do these robots still want to sit on a chair when clearly they know such action is very inefficient? [Answer] ## The world is still designed for humans In any social engagement it is important to know when to sit or stand. Depending on the social situation sitting, standing or the refusal of sitting or standing can mean a lot in social standing, ease of a person, threat and more. It is important to keep to these social rules if they want to fit in. More important is that the world is designed for humans. Many things are more easily accessible by sitting. Desks, computer terminals, dining tables or even just filling a car or a public transport vehicle. All can be used or used more to the full extent. Saves a ton in (design) costs if you don't need to adapt part of the world to robots with special computer terminals and cars. You ask: "*So despite all the trouble why do these robots still want to sit on a chair when clearly they know such action is very inefficient?*" Humanoid robots are inefficient by definition. Adding an inefficient method would be expected – to make it fit in – rather than frowned upon. [Answer] ## Bipedal locomotion is inherently unstable. We never actually stand still. Try it! You'll see that you wobble and waver constantly, with micro-adjustments to your posture and center of mass all the time to avoid falling over. Standing completely still is not a natural state of things for a human. You can do it with some effort, but it's not comfortable for most of us. Likewise, if your robots have similar proportioned body-parts to humans, your robots must also constantly adjust themselves to stay upright. Even for a robot, sitting in a chair is more energy-efficient than standing. [Answer] **The robots compete with each other to see who can be the most human-like.** Sitting down was a piece of the repertoire from long ago, when the competition among robots first started. Robots now not only sit down, but tip chairs back, cross legs over, bounce nervously and other pieces from the human repertoire their keen observations have picked up. A robot that comes up with a new human behavior to mimic will get appreciative nods from the other robots who notice. They wrinkle their noses, seem to doze off, push hair out of their eyes. Certain behaviors are trendy - perhaps long hair and a head toss to throw it over a shoulder. And this summer all the robots have their hair long and are tossing their heads! Occasionally a robot will pick up and copy some behavior he saw someone do that is not normal human behavior - a person squirming uncomfortably from ill fitting underclothes or a painful hip. Particularly edgy emulators will cherish such one-off behaviors. More conservative robots will stick to common behaviors. [Answer] ***Frame Challenge:** They would not break a normal chair by placing their whole weight on it.* ### How heavy could these robots actually be? Normally if an OP says "a robot is heavy enough to break a chair", I would just take this at face value; however, the OP specifically gave enough details to prove that his robots should not be heavy enough to do this. > > the center of gravity is much higher for them because of the heavy battery pack located inside their chest > > > Since you mention that robots are top heavy because of the weight of their batteries, we can assume that a robot has a density of somewhat less than that of a battery. Older styles of robotics were very heavy because of their use of lead-based batteries; however, lead based batteries are no longer used in robotics. Instead, we now use lithium ion batteries which hold more power while being about 3 times less dense. A standard automotive lithium ion battery has a density of about 0.92g/cm^3 which is actually slightly less than the density of the human body; so, for a chest full of batteries to make a robot top heavy, it would have to actually be LIGHTER than humans, not heavier. Even if we assume the use of older style lead batteries, your robot would still have to be significantly less dense than its batteries to make it top heavy. If the android is the size of an average human, then that means it weighs in at somewhere less than 200kg to be able to meet the description given by the OP. ### How heavy should they be? As it turns out, the batteries are not actually the heavy part of a robot anymore. To figure out what an actual android should weigh, the best thing we can do is look at actual human sized robots being built today for public consumption, and see what they weigh. The two best examples you will find are probably the Promo-bot (about 152 cm tall and 100 kg) and the Kiki (about 160 cm tall, 80 kg). These are both a bit on the short end; so, if we assume your androids are made a bit taller to equal a more average Western human's height of about 172cm we'd get something in the 107-145kg range. So, even in the real world with our relatively privative technology, human-like robots only have a density of about 30-80% greater than humans. These robots also both drive on wheels instead of walking and have slightly over exaugurated body volumes; so, with legs and actual human proportions, they should actually have very close to human weights. Even if you assume a higher density metallic framed robot designed for heavy labor, it will still be much less dense than you may assume. Significant amounts of the robot's internal space needs to be dedicated to air gaps to give room for things to move around, hydraulic fluids (1.0-0.8 g/cm^3), assorted electronic components (0.6-0.4 g/cm^3), the afore-mentioned batteries (0.92g/cm^3), etc... So even if you assume the structure of the android is made of a denser structural metal like steel (as opposed to something more practical like aluminum, titanium, fiber composites, or polymers), the steel bits are still unlikely to account for more than 20-30% of its actual volume... so even in this case, it is still very unlikely for a human sized, heavy labor robot to exceed 200kg. ### Would this break a human chair? The average human chair is rated for about 115-365kg; so in theory, a human sized robot could exceed the recommended weight capacity of a poorly made human chair but chairs are not just designed to survive the weight of a human, they are designed to survive the impact of a human sitting on a chair. Since humans can be quite clumsy, we often inflict an impact force much greater than our resting force on the objects we interact with. So the weight ratings on chairs are normally 1/3 the load weight that the chairs actually break under during testing to account for how humans are expected to interact with it. This means that as long as you are careful about how you set your load on a human chair, it is actually designed to have a holding capacity of about 345-1095kg. If we assume that androids are even just a little less clumsy than humans, then thier extra weight could be easily offset by how carefully they sit allowing any android to sit down safely on practically any human chair. ### So why then would Androids Sit? Apart from the obvious points already made about the social advantages of sitting, even when there are no humans around to perform for, they would would still benefit from sitting down to relax. It takes less energy to stay upright in a sitting position than a standing one because minor changes in your environment are less likely to knock you over. Sitting vs standing may not seem to conserve any power if your robot can just lock into a standing position, but in a standing position, it will need to continue to maintain full awareness of its body and surroundings to make sure nothing changes that would cause it to fall over and risk being damaged. The safer nature of siting means it can reduce power to its sensory and processing systems by reducing the cycle rates of how often it processes its environment. This also extends how long it takes for its electronic components to burn out if they are not always running at the higher capacity. It may also slightly reduce stress on the robot's hydraulics causing those to fail slower too. Even though your hydraulic pumps may lock into a position, the outward pressure of a hydraulic system on its container is higher when it is under load increasing the risk of it forming a leak. [Answer] Apparently continually standing when there is a seat available in a conversation with a sitting person is not considered socially ok, or is seen as aggressive or makes people nervous or isn't polite... if personal experience is anything to go by. They already alter themselves for social reasons, might as well suffer a bit for social reasons as we all do anyway. I wouldn't put it past them to go the extra mile to keep up appearances and remain polite with humans. [Answer] **Inductive charging** Are your robots powered by a nuclear rtg and run forever? Or do they have a battery pack that needs to recharge? If you own a business that owns robots, or have your own robot maid at home, you'll probably have purchased said robot(s) with a charging dock - which just so happens to be in the shape of a rather ergonomic chair. No need for messy wires or tedious battery changeouts, all new robots come with built-in inductive charging! [Answer] Sociology. The group psychology of amicability is pretty simple, even if we're unaware of it. Standing in the presence of other people who have to sit is an intimidating act, if not outright hostile. The mafia don, the kings of old, if you were in their presence and someone was standing, it would be them and not you. Even in the fictional portrayals that you see on tv today where it's the opposite... the petitioners enter the court with the big guy sitting on throne, think about the details that go into that. As they approach they must bow or kneel (no longer stand). And there are big beefy guys with spears/swords/guns standing between them and the king, ready to put an end to any nonsense that might occur. (Guards and servants being the exception to the "no one stands" rule, and their loyalty is heavily policed while they are made to know their "place".) If Mr. Robot is going out to a work lunch with his colleagues, worse than him not eating with the rest is his tendency to stand there, all stiff like the T-800 endoskeleton from The Terminator. Ready to pounce and murder the savior of humanity or not. Boardroom meetings. Casual visits. None of these things work if they insist on standing. Perhaps it'd be no big deal if they were little tin cans like R2-D2, but if they are proper (humanoid) androids, then they just have to sit. This is so basic though, that I would hesitate to bother to explain it at all. No one reading your story or playing your rpg will seek to poke holes in this, though if they do now you can wallop them with a good one. [Answer] # Don't tell the humans, but it's a toilet! Hydraulic humaniform robots need state-of-the-art lubrication. Molecularly engineered, tested durable <insert motor oil ad here> ... but nonetheless, *degradable* lubricating oil. They take an occasional social drink to refresh themselves. And every day or so, when no one is looking, they use a fine gauge prehensile needle mounted in their ... posterior port ... to penetrate the fabric of a neglected chair they find some pretense to sit upon. The needle threads its way around the undercarriage and gives each joint and wheel some expired and degraded robot lubricating oil that is nonetheless quite suitable to keep a human-grade chair spinning and wheeling across the floor smoothly enough to remain the office toddler's favorite toy. The humans still think the robots on the night shift must have a can of WD40 stashed away somewhere. [Answer] (My answer is inspired by [Ruadhan's answer](https://worldbuilding.stackexchange.com/a/218425/6712) to the question.) ## For Safety Standing is relatively unstable for a humanoid biped. Especially when such a biped is top-heavy. These robots have vital, heavy parts (batteries) located in their chests. Should the robot fall over from a standing position this can damage the battery and effectively destroy the robot. When not actively moving, the robots are eager to stabilize themselves either by leaning on walls, sitting, or whenever possible lying down. Every opportunity to lower their center of gravity is a chance to reduce the risk of damaging their vitals should they fall over or be knocked over. It is worth the extra energy cost to reduce the risk of irreparable damage. Perhaps when they sit, a third stabilizing leg can be extended from their spinal column to reduce any weight placed on a chair and reduce the need for keeping actuators actively balancing them in a sitting position. This would give them a strong preference for chairs that have no back or that have an appropriate hole in the back. Lying down would be preferred when stationary for long periods of time, but is avoided otherwise because it requires the most floor space, and takes the most effort for getting back into a standing position. [Answer] Ah, you must be talking about the A301-B model house droid. I was on the design team and I get this question a lot. When Nano Robotics wanted to break into the domestic market, we were tasked with converting our widely popular Mudrertron 9000 killbot into a more family-friendly model. We didn't have time to completely re-engineer the internal model so we had to get creative. At first, we simply re-trained the internal reality model to do nothing at all when it had the urge to kill. However, that resulted in long periods where the robot would become unresponsive any time you tried to talk to it and the marketing guys didn't like that. It was actually my colleague Markus who came up with the idea to have them sit. That way when you talk to it it seems like it is really listening! So, that's your answer. Any time you see your A301-B sitting down it's because it actually wants to kill you but can't! [Answer] # Chairs are docking stations that connect into mains power and high-speed network links Another answer already mentions that they might double as chargers and maintenance stations, but they can serve another purpose too. For the really computationally demanding tasks that make your overclocked brain take up 10x the energy, or that demand really high capacity network flow, you want to be wired into the grid. In real life, high-performance server equipment never uses WiFi or battery power, and instead always uses wired power and network connectivity. It's worth considering when the robots frequently sit down. Sometimes it's for committees (social and political emulation is a major power hog), sometimes it's for social interaction with humans over food and drink (again, social and emotional emulation at that level can be demanding), sometimes it's just for sitting down in small group to hash out a difficult problem (a lot of required computations for simulating possible solutions, network connectivity needs to be very fast to cross-reference and retrieve external data). Each of these are so demanding that it would make sense that chairs are designed with these facilities in mind. [Answer] **The same reason that humans sit on chairs, to relax** I've been working with robots for a couple of years now and there's a big hidden issue that most people aren't aware of when it comes to actuator design. This mostly applies to electric actuators, but there are some similarities with hydraulic ones. If you read the [MIT Mini Cheetah actuator paper](https://fab.cba.mit.edu/classes/865.18/motion/papers/mit-cheetah-actuator.pdf) you'll see that **low** gear reduction and a big motor is preferred compared to the high gear reduction and strong (but slow) motors that most people expect in robots. This style of actuator transmits the forces from the ground back into the motor very efficiently allowing the motor to act as a virtual spring that's computer controlled. This also means that the motors need to be constantly consuming power to maintain balance, just like human muscles. It then makes a lot of sense for the robots to sit down so they only have to balance the upper half whilst sitting on chairs. Or almost no balance and no power required if they're also resting their arms and back comfortably on the chair. This answer somewhat ignores the premise of your question, but I believe hydraulic actuators that will be used in robots will require the same backdriving allowance. This means there needs to be a path for the hydraulic fluid to flow backwards with an active controller that maintains balance by turning the piston into a virtual spring, but using power in the process. The alternative is the robot locks it's legs into position which will require no extra power, but that makes the legs perfectly stiff and unable to balance. Stiff legs are also incredibly prone to damage in case of falls; you really want everything to be floppy to absorb as much energy before breaking. The other premise that robots need to partially use their legs to avoid putting all the weight on the chair is also questionable. If you insist on doing that then the robots will be sitting quite menacingly on chairs, leaning forward and with the legs firmly placed below their center of gravity. They'll look like their about to pounce on you from whatever chair their sitting on; just try sitting on a chair with only half your weight and see how you look. The balancing physics of a humanoid robot and a human will be very similar even if the center of gravity is a bit off. I'd suggest you make your robots no more than twice heavier than a human (you probably want the arms and legs made of light carbon fiber anyway). In that case most chairs will be fine under a robot, but it would be a nice detail of the story that all your robots need to carefully inspect the structural soundness of their chairs before sitting down. ]
[Question] [ 1. They have tried Democracy 2. The civilization is very much similar to human civilizations but I want it to stay as a monarchy yet still have technology advanced enough to travel around the galaxy. Is it even possible? [Answer] **If you want it that way ...** Democracies like to pretend that democracies are (a) superior forms of organization and (b) sort of inevitable. But if you look at the model of history underlying that claim, you will find something much like Marxist [historical materialism](https://en.wikipedia.org/wiki/Historical_materialism). And most people today believe that Marxism was a dead end. Is social and political history really marching only *forward*? And where is *forward,* anyway? So consider this: * Is your monarchy an absolute monarchy, or is the monarch at the top of an aristocratic oligarchy? An absolute monarch, ruling by birthright, risks that you get an idiot every couple of generations who destroys everything. Or just an ordinary human, when the situation calls for an extraordinary leader. If it is possible in such a situation that **actual** power goes to a [shogun](https://en.wikipedia.org/wiki/Shogun) or [maior domus](https://en.wikipedia.org/wiki/Mayor_of_the_palace), the civilization may cope better. * Does your setting have FTL travel and communications? If not, organizing interstellar elections is all but impossible, anyway. A monarchy may be suitable if the monarch sends [viceroys](https://en.wikipedia.org/wiki/Viceroy) and orders which arrive decades later. The [Traveller](https://tvtropes.org/pmwiki/pmwiki.php/TabletopGame/Traveller) roleplaying game explored a setting where different factions of humanity found different ways to cope with communications lag (even FTL communications lag). * Right now democracies worldwide are being challenged by autocracies. It would be nice to believe that democracies will win, but that takes effort on the part of the democrats. Quite possibly, social media is good at destroying reasoned debate, and promoting personalities over policies. [Answer] > > Hence it is that such democracies have ever been spectacles of > turbulence and contention; have ever been found incompatible with > personal security or the rights of property; and have in general been > as short in their lives as they have been violent in their deaths. > > > So James Madison. Someone with less support for the form of government would probably put it more strongly. Your aliens find that putting the government in too many hands results in everyone's trying to live off other people. Shut most people out of it, and they will grumble but do their work. It needs three things: 1. A way to coopt talent in the lower classes. Your monarchs and the nobles they use to implement their rule keep a sharp eye out for signs of talent. Such people are to be inducted, as quickly as possible and definitely in childhood if at all possible, into schools and social groups so they can be induced to work with the government. Noble titles, and intermarriage, lie ahead as possibles. Your culture may even practice adoption for quite lowly children to become the legal children of people of quite high birth. 2. A way to contain grievances. Lower classes need ways to petition the government and a fair degree of confidence they will be heard. 3. A way to remove upper class people who are incompetent. Shuttle them off to a monastery or kick them upstairs are possibilities, but they have to be kept where they will do little damage. They expend a lot of resources on ways to test people and put them in an appropriate position [Answer] All political systems based on mass mobilization (democracy, fascism, communism, hybrid variants of all three) arose in contexts where the loyalty - or, at least, service - of large numbers of individual citizens was required to project military power. And that development in turn was almost entirely dependent on the basic unit of military power becoming an individual volunteer or conscript soldier with a firearm. (Or, later, groups of conscript soldiers manning artillery or vehicles.) As soon as the basic unit of military power ceases to be an individual soldier with a firearm, we have no reason to assume that current forms of political organization will continue. It is very easy to imagine a world where the basic unit of military power has become an armed robot directed either by an AI or by a very small class of technicians. In that world, whoever controls the robots ultimately controls all political power, and will no longer need to trouble themselves with securing the loyalty of mass movements like political parties. Individual human loyalty will be nearly irrelevant to them. In the case where a small class of technicians is still required, you might end up with a mixed monarchical / aristocratic system. In the case where the robot militaries can ultimately be controlled by a single individual, you will get absolute monarchy, or its equivalent under a different name. (Assuming human beings manage to maintain operational control of their AIs at all.) As a result, it's entirely possible that advancing technology won't make monarchical or absolutist political systems in your interstellar civilization less likely - but will make them *more* likely. Who controls the technology enabling interstellar travel, and how do they control it? Who controls the technology allowing for the application of military and police power? If those groups are small enough, and decide to call themselves "kings", then you have tenable monarchies. [Answer] As a frame challenge, this question is based entirely on the assumption that only a democracy can lead to technological advancement sufficient to travel around the galaxy. **TLDR** There is absolutely nothing in the concept of Monarchial Rule that prevents a society ruled by it from advancing to a very high level of achievement. The trick is to prevent the Adversarial Approach from restricting societal advance, not absolute rule itself. I doubt if anyone would, for instance, argue that Apple was lead by a 'democracy' instead of by 'autocratic rule'. If monarchs take an adversarial approach to their own people, progress is thwarted, just as certainly as it is under an adversarial 'democratic' system. However, if a monarchial system takes a benevolent co-operative approach to the people, then it can certainly be much more effective than an adversarial-based 'party politics' democratic system. This is evidenced throughout human history. In fact, as is evidenced in the world today, centrist single-body non-adversarial type governments such as monarchies, theocracies, and family compact party-less type systems are perhaps the better system that can assure the long-term stability necessary for prolonged, sustained progress. Adversarial 'win-lose winner-take-all' one party against the other polarized systems that are the basis for democracies today suffer horribly from zig-zags in policies and governance, leading to inevitable chaos and stagnation as one side 'undoes' what the other side has accomplished. Progressive projects inevitably get cancelled every time a new government is formed. Progress under such a system depends entirely on the fact that corporate governance is far from democratic, and the institutions that were driving the progress (corporations, Universities, and entrepreneurs) were able to peruse long-term stability of governance through the unlimited term reign of their CEOs, Presidents, and Chairmen, to assure long range plans were followed. It is also a completely false premise that only a 'democracy' can enforce human rights and be governed by the Rule of Law. In fact, as is evidenced in the world today, populist democracies are antithetical to human rights and the fundamental freedoms of freedom from oppression and freedom from tyrannical intimidation. [Hammurabi](https://en.wikipedia.org/wiki/Hammurabi), almost 2,000 years before the Christian era, consolidated the 'universal Rule of Law' and encased 'Individual rights' in the law, guaranteeing it was upheld and respected by all, including the elites, under a system that was far from 'democratic rule'. More like a benevolent dictatorship. In order for fundamental freedoms, social responsibility, and the rule of law to be protected, there must be a strong heavy-handed system to do so. Americans, for instance, tried a 'Constitutional' approach, but failed miserably, as each side of their adversarial system interprets the Constitution to serve their own needs, with no independent impartial overall 'oversight' body to assure the spirit of the Constitution was enforced independent of party politics. As originally intended in the American Constitution, the American military swore their loyalty to enforce the Constitution, but somehow along the way, the 'sense of loyalty' shifted from their oath to uphold the constitution to the concept of the Chain of Command and Loyalty to the President as Commander in Chief dominated above their loyalty to the principles of the Constitution. The fact that a 'constitutional crisis' could ever arise over this narrative is very telling indeed. Somehow, in any form of Constitutional Government there needs to be a strong, politically independent, unassailable body that protects the Constitution unilaterally and unambiguously, unchallenged and immune from political intervention or manipulation, yet has no political power itself. Ultimate power to enforce the Constitution, immune from political hacking, intimidation, or intervention, yet no power to make or enforce laws, just the power to enforce the Constitution. Canada's Governor General system, for instance - a completely separate branch of the legislative body even from the courts. Perhaps the best form of government to guarantee progress and to protect individual and social rights and freedoms over millennia, rather than decades, would be a Constitutional Monarchy, where the monarchy rules and has the ultimate say, but is limited in scope by an over-riding Constitution that it is morally, ethically, legally, and culturally bound to follow', based on the over-riding premise of 'honor' rather than 'power'. As per John Locke, should the Monarchy not abide by the Constitution, the Monarchy can be constitutionally replaced, but otherwise remains intact. Of course, the Constitution has to be socially responsible and built on equality to begin with, before social responsibility and equality are protected under it. [Answer] **We can learn a thing or two from good old Earth** > > It’s good to be the king. But, when it comes to a nation’s economic health, it’s also good to have a king — or queen — on hand. Monarchs open economic doors. > > > “In the presence of royalty, companies can enter circles they wouldn’t be able to get in by themselves,” says Angélique Heijl, deputy director of international economic affairs at VNO-NCW, the largest employers’ organization in the Netherlands. “This holds particularly true for countries where the government plays a large role in the economy.” > > > Monarchs typically serve their respective nations longer than democratically elected heads of state: The recently abdicated Dutch Queen Beatrix was on the throne for 33 years; Elizabeth II of Britain has held her position for 61 years and counting. This kind of leadership stability gives these particular figures additional sway in the business community. ([Source](https://fortune.com/2013/04/30/the-business-case-for-monarchies/)) > > > When it comes to a galaxy-spanning empire, the businesses are ***incredibly important.*** So much so that SciFi (e.g., Johnny Mnemonic) has played around with the idea of business being government in its own right. The influence of business on a civilization so advanced as to span an entire galaxy cannot be over-estimated. Therefore, a government that partners really, really well with business has a high degree of believability. And a monarchy is it. Governments do two things: they manage wealth and they impose order. The later is done with the threat of violence ("if you break the law, we will take your freedom!"). The former is the basis of at least two college-level economics classes. But a monarchy and its ability to *grant patents and charters* has an excellent chance of partnering with business. **Add the inherent difficulties of communication to the mix...** To add to the boiling pot... democracies kinda depend on reasonably swift communication. That comes from being small in size (Ancient Greece...) or having a tremendous communication system (modern-day democracies). When you depend on the people to elect their leaders, you need a way to ~~manipulate~~ inform your population so they can make wise choices. Which suggests that the worst conditions for a democracy would be a geographically large area with remarkably poor communication. Given that condition, it's easy for pieces of the democracy to begin breaking away into independence (we've seen that in our own lifetimes!). A galaxy like the Milky Way is 100,000 light years across. Ignoring for the moment that massive black hole and maelstrom of radiation in the center, that means that your communication must at best cross 50,000 light years to reach everyone. Let's assume FTL... to get a message across in one week you need to travel 2,600,000X the speed of light. Well, it's SciFi, right? What's a little thing like hand-waving excessive speeding? But that's the only way to have a *practical* democracy. Super speed. Otherwise people can't be kept informed in a way that makes democracy work. The longer it takes to inform the people prior to an election, the more your democracy will look like a monarchy anyway. **And too many voices kills democracy** Finally, here's your last problem. A galaxy-spanning bureaucracy would require a lot of levels of abstraction to work. Ignoring how to govern a planet (our attempt at one-world government doesn't work fabulously), we can assume that each planet would want a seat at the proverbial table, right? I mean, think about how Star Wars presents the Senate. I think that's *really optimistic.* Millions (if not billions) of planets. Maybe 1,000 per region of authority (The U.S. Senate represents 50 states, and it's unwieldy). Thousands (if not millions) of regions of authority. A senate of senates of senates.... Each having executive and judicial branches... Which looks an awful lot like a parliamentary monarchy pretty quickly. **Conclusion** I think it's more likely for a monarchy to exist on a galactic level than a democracy as-is. I'm just sayin' [Answer] # **Constitutional Monarchy** Same answer as for the UK on Earth, and several other countries where the monarch is a lower-profile figure (for example Sweden, Spain, and the Netherlands. Also in different cultures and with constitutions I know little about, Morocco and Thailand). ## **The monarch is a figurehead with no real power when things are working normally.** The monarch has enormous unused power to sort things out should the normal processes of government become deadlocked or worse. The least radical way to to this is to dissolve the government and call fresh elections, over the heads of the politicians. If a coup is attempted, it is the monarch to whom the military have sworn loyalty (also the civil service, police, etc.) and a call from the monarch to oppose the coup leaders might succeed. (It did, in the 20th Century, in Spain) Think of a circuit breaker in an electrical circuit. It does nothing except "watch" almost all the time. If the circuit overloads, the breaker pops, preventing serious consequences. But if it pops for no good reason, it is soon replaced with one that works correctly. So would any monarch who got ideas of becoming politically active outside a constitutional crisis. They would be escorted to a comfortable padded cell while a relative was installed as the new monarch. And the advantage of this system? In my opinion, any person who seeks the power of becoming president, thereby reveals his unsuitability for the role! Better to have somebody who is in that role for life by accident of birth, and who is trained to it by experts in the constitution and crisis resolution. As for a galactic civilisation: the biggest issue is speed of transport and communication. You can make this as fast or slow as you want. You have historical examples to draw on. The Roman Empire, which was limited to pony express speed for messages and marching speed for moving people. The Islamic Caliphate, with similar speeds, but much greater absolutism, an absolute dictator supreme caliph ruling kingdoms whose rulers were almost as absolute in their own realms. The British empire, already a constitutional monarchy, with the electric telegraph for near-instantaneous messaging, but limited to the speed of ships and steam trains for moving people. The modern world, with jet aircraft and faster missiles. This will be a far more significant influence and limit on possible forms of government, than the choice between a monarchy and a republic (with elected president of greater or lesser power). (Asimov is on record as saying that his Foundation was modelled on the Roman Empire and its fall). [Answer] **A statistical fluke, or something made to look like it.** Imagine a monarch using their power to abolish feudalism\*, introduce universal healthcare, retirement funds, free education, meritocratic distribution of positions in administration, ... and then none of their heirs screwing the pooch. (\*) One biiig exception there, of course. Say from a earth-equivalent 1800 onwards. Each monarch reigning for a mean of 20 years until the civilization can journey the galaxy (year 2525 for absolutely no song related reason) - that would put us into the beginning of the reign of GoodMonarchTheWise XXXII The odds of that happening are very small (assuming 1 in 10 people is good enough (or not-bad enough) to be that monarch,the chances would be 0.1^32) but this is fiction, right? As i alluded to in the header, there might be some power helping the odds along, but that power (a secret cult weeding out the heirs? a transdimensional being executing an aeon-long polsci experiment?) would then ultimately decide the leadership position, thus this influenced political system may or may not be a monarchy (depending on the way that power is organized). [Answer] (this answer focuses more on the *political* reasons than the *science* reasons, but they're related). # They're the only ones who want to expand A general rule I've seen proposed (but is certainly disputable) is that monarchies are *efficient* and *want to expand* more than democracies. The reasoning being that democracies take on additional overhead when expanding (new voting districts, different administrative centers, etc.) while monarchies gain more in tax revenue than they lose when expanding (they don't have to deal with things like checks and balances and so need less administration for new parts of their empire). Obviously, this is not always true: * [Democracies can want to expand](https://en.wikipedia.org/wiki/Manifest_destiny) (although I think it's worth noting that the US is more of a [federated](https://en.wikipedia.org/wiki/Federation) [republic](https://en.wikipedia.org/wiki/Republic) than a democracy) * Not all monarchies seem to expand much (see any modern monarchy like [Eswatini](https://en.wikipedia.org/wiki/Eswatini) or [Jordan](https://en.wikipedia.org/wiki/Jordan)) (also worth noting that, if true, this theory does not make monarchies *better* than democracies, just *better at expanding* than democracies) If monarchies do have more incentive to expand, it could be not so much that the monarchy *made the technology* to take over the galaxy and more that the *technology was already made* and the monarchy was the only civilization who *wanted* to expand their empire. # For the glory of the empire! Alternatively, the monarchy could have developed technology *specifically* to colonize the galaxy. Rather than working for personal profit, perhaps the engineers worked to spread the wonderful glory of the god-emporer. # This is not too far from what happened on Earth In earth's past, monarchies have also expanded to become great empires (think democratic Greece vs. Alexander the Great's Greece or British Empire vs modern UK). I think it's very much in line with history to see a monarchy dominate the galaxy before any of those slow-moving democracies do (how long that will last is another matter). [Answer] **Consider that the monarch doesn't just have absolute power, but absolute obligation.** By tradition, or other means, consider the situation where the ruler has spent their entire lifetime being brought up to believe that their role and responsibility in life is to guide their civilisation to greater heights. They have been educated since birth on every subject considered important to your race for progression of their civilisation. Perhaps even the partners of royal family line are also chosen based to a large degree on merit, so that aptitude finds its way into the genetic line. The end result should be that every leader is benevolent and wise. The indoctrination is strong enough and the prestige so great that one abusing the power is imply unheard of. Perhaps the biology of your species even encourages this behaviour. They can still delegate any number of decisions to suitable organisations, but have the necessary background and wisdom to impose their executive power where it is of the most benefit to society. [Answer] # Aristoi + Eugenics Your aliens have selected a genetic class that systematically weeds out people with "undesirable" traits. With genetic engineering and social programming, they have created a class of people who are genetically and educationally "optimized" (at least in their minds) for rulership. But this class actually lives quite humble lives. They're really just administrators and bureaucrats living comfortable but not spectacular lives. Because they are surrounded by strict rules about what they are allowed to have and do, they really don't have much freedom. Sometimes, half the battle of who should be in charge is just picking a fair way to decide. The monarch may be better, or at least they are no worse than the next guy. # God-Rulers: Your original great monarch is still alive - sort of. AI has created a simulation of the great founder. Each new "Emperor" is considered a reincarnation of this ruler, but they are really a mouthpiece for this AI. This program rules wisely and impartially, worshipped as a god by the people. # AI monarchs: Or why not just make it official, and AI's ARE the monarchs? Each new "ruler" is designed as an upgrade of the previous system. # Humans don't matter: No one cares who the ruler is, except the humans. And they really don't count. The society provides all needs for all citizens, but that's a fraction of a percent of GDP. Every important decision is made by corporate boards or wealthy plutocrats, but these are mostly AI's, downloaded rich folks living in computers, or hyper-advanced cyborgs. Monarchs are simply not capable of understanding governance at this level of sophistication and are kept away from decision-making like silly children. It seems like the ruler is in charge, but real administration is done by computers. The REAL powers don't care if the monarch executes people or builds lavish palaces or even carries out whole wars with other civilizations. It is STILL less than a percent of GDP. If it makes the humans feel relevant, then why not? ]
[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/201537/edit). Closed 2 years ago. [Improve this question](/posts/201537/edit) Suppose there are some swords (not man made, but abundant enough to arm an army), that grant their users a magical abilities such as: extremely heightened reaction/increased perception of time and injury regeneration, short range teleportation, high speed, area of attacks, teleportation into a void/dimension where they can control some laws of physics/basic reality to fight an opponent in a 1v1/ 1vX against whatever their opponent may be, basic natural elemental control etc. (They get a single ability, not a combo), The swords are rooted in some basics of science and isn't just a delete button for their wielder to use against their opponent, and have an incredibly high durability. The swords in nature are alien/not of the earth, so they cannot be manufactured by humans, incredibly improper use can result in their destruction. There is no other magic in this society/world. I am trying to strike a balance where the swords are powerful enough to deal w/ extremely dangerous threats found on both the earth and beyond, but not strong in that they can just bust a continent or planet open because of magic, or have a group of people armed w/ swords simply control the entire world because of the sword's power. In the same vein, I also cannot have the firearms SO powerful that there is absolutely NO reason to use such magical swords in a near future setting. Why would a near future society/humanity still use guns mainly in their military against both humans and other entities, when these swords grant users such power? Edit: Some idea of how these swords work: The swords need to be held in order to be activated, further more they can't just be used in the real world wherever if that makes sense. What ends up happening is that they essentially create a large barrier/ container in an area where they are able to use magic. In lower level barriers/containers people can exit and enter the barrier/container as they please, higher order containers are a bit more tricky. For visualization purposes imagine that a certain radius around the user is teleported into a different subspace where the laws of physics are slightly altered along w/ some magic to allow the swords to function (the laws of physics cant be manipulated such that it makes chemical reactions inert so that guns dont work, or gravity reversed etc.). The laws are changed in order to allow just the sword to function in its true capacity, everything else is remained unchanged. This means that only the sword users and the sword itself are augmented via magic. [Answer] ## Training These swords may be superior as individual weapons, but militaries and police forces prefer guns for the ease of training and standardization. A new recruit can be taught to use a gun in minutes, and trained to a decent level of proficiency in weeks. Learning to use just a regular sword effectively takes years of practice, and these additional abilities increase the amount of training necessary. Worse still, none of that extra training can really be standardized, since each sword grants one of a wide variety of abilities. Even after all that investment, that master swordsman you spent years training could be killed in his sleep with an airstrike, or sniped from miles away. Meanwhile an entire army platoon equipped with rifles could be replaced in a few months. ## Cost For a military or police there's also the matter of cost. Your scenario implies that these are a modest number of these swords in circulation, but that number is not increasing, and may actually decrease over time. In practice, this will make them extremely expensive, which is another liability for police or military forces since not only do they have a lot of people to arm, but most of those people spend most of their time not using their weapons. The expense might be worthwhile for special forces teams, but in most cases a gun would be a more practical option. ## Unwanted Attention If these swords are both extremely valuable and tactically/strategically useful, carrying them may draw the attention of those who want the weapons for themselves/their nation states/money. A sword is generally not a concealable weapon, and walking around with one might attract more trouble than the sword is worth. Worse still, if these swords are sufficiently durable and valuable, an enemy nation state may opt to just shell the general area the sword wielder is in, and sift the sword out of the wreckage. Remember also, that no matter how powerful the sword is, and how skilled the wielder is they're still going to have to sleep, so even a regular (albeit desperate and/or determined) person could potentially be a threat. ## Too Good to Use Deploying these weapons risks not just losing them, but allowing them to fall into enemy hands. Over time they're going to tend to find their way into the hands of those who secure them the best and use them the least. The sorts of scenarios where the sword's power might allow you to tip the scales in your favor are also exactly the sorts of engagements that military planners would probably never allow them to be deployed in. One sniper bullet may change a narrow victory into a crushing defeat that also hands your opponent a powerful weapon. On the other hand if you know you are very likely to win, why risk using the sword at all? Militaries might focus on collecting and securing these swords to prevent their use entirely. [Answer] The longest sniper shot on record is currently 3,540 meters. At that distance it took the bullet about 7 seconds to get there. The sound of the shot took 10 seconds. The crack of the bullet itself would arrive at the same instant. The target of the shot literally had no warning he was about to be killed, and anyone around beside or behind him would have seen him hit and then heard the bullet crack, and *then* heard the shot, assuming they heard it from three and half kilometers away at all. Now, that is an extreme example, but military snipers can get to a thousand meters pretty routinely. A few hundred meters, trivial. Even at 100 meters for modestly-skilled soldiers with standard assault rifles firing over iron sights. In those cases, again, the bullet arrives before you ever know you're being shot at. Heightened reaction speed is utterly meaningless if a bullet goes through your brain before you know there's something you should be reacting to. The effects on someone trying to bring a sword to a long-range gunfight seem pretty obvious. ***EDIT*** As noted, shooting at 100 meters or more by average soldiers using standard weapons is normal. It only takes a few hours to train someone how to hold and aim a rifle properly, and in a stable shooting, hitting a man-sized target at 100 meters is trivial. One hundred meters is a long way to run charging at one or more people firing semiautomatic and automatic weapons and no way to shoot back. It's even longer if you don't even know how many you're facing or where each is. [Answer] First of all, to kill with a sword one needs to be at reach of the target. If you have 4 enemies each at 300 meters from you, one North, one East, one South and one West, killing them with the sword would require you to teleport in each and every location and slash them. With a gun you just need to aim, fire, turn 90 degrees and repeat: way faster. Then, there is the other issue that the higher in charge want still to have control over the powers granted by the swords. See, in every army ammunition and weapon and never distributed together unless needed. And from the description you make, these swords do not sound like something you want to give to any average Joe fresh out of the drill instructor's hands. Only elite troops will be allowed to use them. [Answer] The problem with melee weapons is that they require a mixture of skill and physicality. The skills and physical traits valued in sword fighting vary by culture, but by and large any melee combat is largley a contest of physical prowess. A 9 year old with an AK-47 can effortlessly defeat any of the greatest swordsmen in history from 300 yards out. Now, these swords do have magical abilities, that does maybe allow your swordsman to narrow the gap a bit, but not if he is getting shot in the head from 800 yards out by a trained marksman with a scoped rifle. He won't even likley know he is being attacked until the bullet has already impacted, so how is he going to get a chance to use any of his abilities? Frankly, I think justifying why all the sword users haven't been killed by gunmen is a more relevant question than why guns are still being used. [Answer] Fire Arms * **Range and Rate of Fire** - so your sword can deflect a bullet at point blank range... how will it fare against 100 rounds per second from a mile away? * **Ammo Factories** - congratulations, you've managed to block 100 rounds per second for ten seconds. Your sword work is truly spectacular! But how long is your stamina going to last against my massive ammunition stockpile? Magical Swords * **Injury Regeneration** - true warriors don't carry magic swords for their direct combat value as weapons. The swords are too short range to be effective on a modern battle front. But the healing they can grant is an incredible boon in dealing with non-fatal injuries. * **Elemental Control** - control of the weather, especially heavy rains and fog can be very helpful on a battle field, obscuring visibility during both attack and retreat. Alternatively, withholding rainfall and causing drought can tax your enemy's supply lines. [Answer] One thing often not thought of when making comparisons like this is that it is *always* safer to incapacitate a target at a distance than it is from right next to them. Even with super speed or amazing durability, it is still safer to fight from a distance. There are a small handful of exceptions to this, and pretty much all of them are predicated on there being a significant power disparity between the attacker and the target. Even in antiquity, a squad of very good archers was almost always preferable to a squad of very good swordsmen if you were talking about actual warfare. Ultimately, the reason that melee weapons were more prevalent than ranged weapons historically comes down to two specific factors: * **Economics**: Quite simply, swordsmen and spearmen were more economical than archers. This, in turn, is a result of both the training being more economical (good archery requires a complex set of skills which all need to be good, while good sword-fighting needs just raw physical ability and some basics of close quarters combat that can be applied to almost any weapon) as well as a manufacturing aspect (mass producing acceptable swords is much easier than mass producing acceptable bows or crossbows, largely because bows and crossbows need much better quality control than swords for them to be useful). * **Asymmetric Protection**: Historically, it was much easier to protect against projectiles than against melee weapons. A warhammer would ruin your day no matter what type of armor you were wearing (even if just because the impact will leave you rattling around inside your plate armor), but a lot of armor was reasonably good protection against arrows. Firearms upended both of those factors, they have much better penetrating power than arrows or bolts and are both cheaper to produce at acceptable quality and less of an issue to train for. In your case, I see the economic side of things being the primary factor. You have an unknown number of rare, irreplaceable weapons balanced against trivially mass-producible commonplace weapons. Given no other differences, anyone with even the most basic understanding of military strategy is going to favor the cheap commonplace option over the rare irreplaceable one. This likely will be compounded by differences in required training. Modern militaries can turn out acceptable rank-and-file riflemen in a couple of months, but getting to the point that you can handle a sword properly takes most people *at least* a year, and that’s ignoring the very likely need to extend that training to cover the special abilities of the sword. Given all this, I envision that things will develop in a very specific way in this world: * In antiquity, the wielders of these swords would have been major historically significant warriors. Not necessarily generals or commanders, but the heroes who lead their sides to victory. The described abilities are, in and of themselves, more than enough to turn the tide of a battle in the classical era, and still possibly enough even up through the late 1800’s if applied correctly. * Parallel to this, ‘normal’ military forces would have developed pretty similarly. Possibly some differences to try and protect against the abilities of the wielders o these magic swords, but otherwise things will be pretty similar (the swords are just too rare to make much more of a difference). * In modern times, the wielders of these swords would be treated similarly to special forces, but likely kept in reserve much more aggressively than conventional special forces, because the swords are irreplaceable and losing one would be a major blow to the nation. Essentially, when these guys get sent out, you know things are seriously bad and the regular military forces are not capable of dealing with it. * In terms of training, even back to antiquity (assuming sensible people are in charge, not stupid aristocrats), I envision prospective wielders being carefully selected for some degree of compatibility with the sword, followed by lengthy training to produce as skilled a wielder as possible. It’s likely that there will be multiple trainees in parallel, and possibly even multiple wielders for any given sword at any given time, with the intent of always being able to deploy a sword when needed. [Answer] How many swords are there relative to human standing militaries? Are there enough swords for entire human militaries across the world to replace guns? I would assume that the likely answer is **no**. > > Why would a near future society/humanity still use guns **mainly** in their military against both humans and other entities, when these swords grant users such power? > > > Humans will likely *adopt* the use of said magical swords, but its limited amount plus difficulty training people in swordsmanship make it not suitable for regulars. Instead, a small group of soldiers will be trained to wield these swords and be embedded to the main army roster in various ways. 1. **Reconnaissance, intelligence, espionage** Hyperspeed and/or teleportation, regeneration, heightened reaction/perception? This combo screams "perfect spy/scout". 2. **Assistance in transport or evacuation** Again, hyperspeed and/or teleportation? Although sword wielders can only use these capabilities sparingly, at least they can be instructed to do so only for critical situations (e.g. Dunkirk or D-Day). 3. **One-man engineer corps** They can make damage comparable to artillery strikes once in a while with their area-of-effect attacks. Having them augmented in a regular infantry corps roster is useful. 4. **One-off recharge-limited supersoldier** Occasionally, an infantry team runs into an unexpected encounter with an enemy larger team. Magic swordwielders can Hulk up their power for a short time, banishing and fighting the enemy into the mirror dimension, saving the team from surrender or destruction. Humans will still use guns as standard-issue soldier kit. Yes, the swords will be used partially, but it won't replace rifles. Why? 1. **Easy training** People can be trained well to use firearms faster than swords. Duck-and-cover and return-fire discipline is also (presumably) easier to instill than sword combat discipline*citation needed*. Even with all the skills, it's still a sword to wield. 2. **Easy production** Guns can be made in large amount (and so the number of people available to use them). There are just times when quantity with slight quality wins over slight quantity with pure quality. 3. **Previous popularity** Guns and the accompanying current 'conventional' toys of war have been used extensively in recent history in comparison to these new swords. It will be easier for militaries to develop ways to either improve, patch, or extend the already existing roster of tools and systems. It takes time to study how to best use these swords, especially now that we have other very powerful weapons that we're already fluently brandishing now and then. No one rushes to mass-adopt them. Likely, adoption will be a very long process given the limited number of items. Some of militaries will just adopt them for the sake of leveling the playing field and not to prioritize its usage. 4. **Near stigma-free** Given its popularity and mainstream use, no one will brand a gunman "witch" or "sorcerer". Contrast with this new rising magic. It's very easy for an enemy nation to call a nation with major use of these swords "using an army of entirely 'dark magic'-ians", sort out a PR work to stamp it as 'Axis of Hell', produce both local and global consent to gang up against it, then just wipe it out. [Answer] Guns could be more popular because they are simpler to make (swords could be handmade or something), "more effective" to use (as in kill faster and more accurately than a sword), or there could be some stigma against using swords that kept people away from them in recent times? [Answer] In a close-range one-on-one situation a person who is reasonably skilled with a swords *may* have an advantage over someone with a pistol, in much the same way that inside about 6 meters (20 feet) a person with a knife is more likely to succeed against a person with a pistol. A *master* with the swords may be able to defeat an entire squad of trained soldiers armed with firearms. The problem is that becoming a master takes a long time and not everyone has the physical or mental potentials to do it. So your number of available *effective* sword wielding personnel is going to be limited to elites only, all of whom have spent years focusing on their mastery of the sword. Conversely it takes relatively little time and effort to become marginally competent with a firearm. Right now it takes about 10 weeks for US Army Basic Combat Training to churn out a class of boots, all of whom are released to AIT with a basic knowledge of how to follow orders, operate in a unit and - among other things - how to handle a modern rifle. While they won't be winning any awards as the world's best soldiers straight out of boot, a large group of relatively inexpensive combat-ready troops can be processed very, very quickly. So for every sword wielder you train there are probably thousands of conventional troops processing through basic. From here it should be obvious that the numbers are firmly on the side of the firearms. Which is not to say that nobody *would* go to the expense of training and equipping elite soldiers with these 'magical' weapons. They absolutely *would* do so. Only the best, most capable and best-suited people would make it into the training, and only a handful of those would graduate... just like the top-tier special forces units of today. And like those special forces units you don't just throw them away sending them against large numbers of regular troops. They'd only get called in when their specific skill set is required. Everyone else will be pounding on each other in the big battles, but your sword wielders probably won't even be in the area when it happens. Instead they'll be dropped somewhere that is a much better fit for their operational abilities. And they'll probably use firearms anyway for most of it. I guess the question becomes: why *would* you train troops to use these weapons? Because swords - especially magic swords - are cool, that's why. Oh, and teleporting up to an a\*\*hole and sticking a couple of feet of magical steel in his guts is a pretty convincing way to finish an argument. [Answer] Explosive bullets are a thing. Sure, maybe you can block a bullet with your magic sword, but what good does that do if it explodes? In real life exploding rifle caliber bullets are rare because the Geneva Convention bans them, and also they're just not necessary. Regular bullets kill regular people just fine. But if there were jedi out there blocking bullets, you can bet that that section of the Geneva Convention would get forgotten pretty quickly. If rifle caliber explosives aren't big enough, rifle launched grenades exist too. Maybe a 7.62mm explosive bullet isn't big enough, but what about a [40mm HEDP grenade](https://youtu.be/Z8diO5uFJOE?t=43)? [Answer] **All the answers above are technically wrong** Every military in the world would want to use these swords in combat. Why? *Injury regeneration* Not all gun shot wounds are lethal, but medical aid or evacuation is expensive. But with these swords you can take cover, activate it, and heal your wound. No specialized medicine, no surgery, and no training required. This reduces your logistical and monetary cost for all your troops. It increases survival rate and morale. Just make sure you use your gun in combat instead of the sword. [Answer] *No defense possible* While swords are fascinating, as most fencers will tell you, guns have a distinct advantage (or disadvantage - this depends on the context) over swords: you can not parry a gun shot. Guns are singularly offensive weapons without any defensive capabilities whatsoever. In a sword fight, if an opponent attacks you, you can always bring your blade between yourself and the attacking blade, i.e., parry the incoming strike. In a gunfight, if you're shot at, there is nothing you can do using your gun to defend yourself. ]
[Question] [ ## Some Context I'm conceiving a universe set in the far future. Humans have already mastered FTL drives and populated several planets in various star systems. They have engines based on singularities (i.e small Black Holes). I'm not looking for a pseudo-sci-fi excuse to allow black holes to be harvested. Humans can do that because I want them to. So startup, containment and storage are fine. The problem here lies in the fail-safe procedure in case anything goes wrong, because I don't think people would sign up for a joyous space trip where a loose screw could make them say hello to an event horizon. ## The Actual Question That being said, I want to know: 1. Can Black Holes be safely dissipated/collapsed/destroyed in case of an unpredictable malfunction of the engine? 2. If yes, how would a mechanism do that in an emergency scenario (fast and **very** reliable)? ## Observations I am aware of [this post](https://worldbuilding.stackexchange.com/questions/20120/would-the-hawking-radiation-from-a-small-black-hole-make-a-feasible-propulsion-s). It clarified a lot but it didn't quite give me the excuse I'm looking for to make this mechanism viable. I've read somewhere that a black hole is the very definition of "collapse" - and this word in my question just means "a way to make the black hole disappear", turn off the engine by brute force (similar to using a fuse to protect an electronic device). [Answer] Start with an 0.1% of Everest-mass black hole. Stuff it into a 0.001 meter radius (1 mm) containment device. At the edge of the containment device, gravity is 0.01 m/s^2 from the black hole. This is microgravity. It emits 1.358944e+10 watts, or 3 times that of a typical nuclear reactor, and it will last 10^10 years before evaporating (slowly increasing in power output as it does so). Every time you lower the black hole mass by a factor of 10, power output goes up by a factor of 100 and lifetime down by a factor of 1000. These micro back holes are dangerous like a hot knife or radioactive core is dangerous; their gravity is extremely local (and if it passes through something the gravity will tear a tiny hole in it). Most of the damage they'll do is from radiating energy at a riduculous rate; actually reaching such a tiny black hole is going to be nearly impossible, as the light pressure will prevent you from falling into it. The hard part is containing the insane emissions the black hole generates, and making it move along with the ship, moreso than worries about gravity. --- A more practical engine might have even smaller black holes and somehow constantly feeding it matter (to grow it and convert to genergy). The emission rate is a function of size (smaller is more power); such an engine runs into the problem that it explodes if you don't constantly feed it mass: to "park" such an engine you have to feed it a large amount of mass. In any case, such black holes are even smaller than my 1/1000th of Everest black holes: they have even less gravitational strength. While their gravitational gradient at their surface is insane, it quickly falls to nothing further away. Black holes are not cosmic vacuum cleaners; they are just extremely compact. You could have a black hole the mass of the sun; but the energy flux is lower than the smaller black holes, the gravity is more annoying to deal with, and thrusting it around is going to be more annoying. And that much matter in a single ship is pretty expensive (there is only so much matter in the galaxy; if each ship requires a solar mass, you'll run out). [Answer] # You invented it, you decide Sorry for coming off as boring but this question is of the sort: > > *I have invented Big Magic™ for my setting.* > > > *Now please tell me how this little aspect of Big Magic™ works.* > > > Well... no-one knows that except you. Especially so since you have taken a figurative **hole** and somehow made usable energy come out of it, energy that you can harvest, which is something we have no idea how it would happen in real life. # Common tropes At it happens you are not the first one to face this problem. And both real life and science fiction have employed different tropes to deal with this: * **Eject the core**. Commonly used in Star Trek. Simple enough: just get rid of the whole thing... eject it out of the star ship. * **Axe the cable**. This was one of the safety options [when the world's first artificial nuclear reactor was started](https://en.wikipedia.org/wiki/Chicago_Pile-1#First_nuclear_chain_reaction). * **Emergency cooling/retardant**. You have a reservoir of something that **will** shut down the engine, ready to dump into the machinery. Problem is that you will not be going anywhere for a while until you clean out the inhibitor. Used in real life [nuclear reactors](https://www.quora.com/How-is-boron-used-in-nuclear-reactors) and on [aircraft engines (assuming you also trigger the fire extinguisher bottle)](https://www.quora.com/Can-aircraft-engines-be-restarted-after-the-fire-handles-have-been-operated). * **Clog in the machinery**. A piston of some stort shoots something big and obstructive into one of the pathways of drive-train and jams it. Works wonders on [table saws](https://youtu.be/rnlTGndRi38?t=3m0s). [Answer] Starships should be fitted with two FTL drives powered by small black holes. When one singularity fails, activate the other FTL drive and move away from the failed singularity at superluminal velocity. On the other hand, basic physics may be the best answer. Assuming the engine malfunctions, then its capacity to extract energy from a small black hole will be reduced to zero. The gravitational field of the black hole will prevent anything from escaping from it. The problem facing a starship with a failed black hole engine will be the black hole itself. It seems not unreasonable to assume that there will be suitable technology to keep a black hole safe. The real problem will be the mass of the black hole. The ship should jettison the failed engine (preferably with a warning beacon) and thus lighten its load. If they possess FTL communications technology, call for help. Either they should activate any secondary FTL drive or engage a sublight propulsion system in the hope of reaching a safe spaceport of call. Failed engines powered by black holes may not be a big problem. The physics of the situation may solve this by itself and there are technological solutions that basically amount to move away from the black hole as fast as reasonably possible. [Answer] There is an [arxiv](https://arxiv.org/abs/0908.1803) article on black hole ships which addresses this pretty well: > > [A] BH with a life expectancy of about 3.5 years has a radius of about 0.9 attometers [and] a mass of about 606,000 tonnes and a power output of about 160 petawatts. Over a period of only 20 days a 160 petawatt power source emits enough energy to accelerate 606,000 tonnes up to about 10% the speed of light. > > > It even addresses (to some degree) what to do if the black hole gets too small, because black hole engines produce more energy the smaller they get: > > Conceivably, unfed SBHs of radii less than 0.9 attometers, having less than > 3.5 year life expectancies, could be used to rapidly accelerate interstellar robotic > probes to relativistic speeds. Robotic probes do not necessarily need to “stop” > and could tolerate much larger accelerations than humans. The problem of > navigating such objects could be difficult however. > The SBH would have to be ejected (or otherwise escaped from) before it > explodes. > > > So the danger is less of being sucked in and more of being overwhelmed by the energy emitted, and the solution, whether because it's at its end of life and is too energetic or someone sabotaged it and its energy can no longer be contained, is an emergency core ejection. It's also interesting because it changes the spin up/down dynamics: generally relativistic flight is shown as symmetric: it takes a long time to slow down as it did to speed up, but for this type of drive that wouldn't be the case, as the singularity would be producing significantly more energy after a long trip (according to the table in that article, a singularity with less than 2 months of life remaining would produce ten times as much energy and weigh 1/3rd as much, giving nearly 30 times the stopping power) [Answer] I just looked at [this article](https://www.google.com/amp/s/www.technologyreview.com/s/419351/how-to-destroy-a-black-hole/amp/), and it says that the formula for a black hole is mass is greater than its angular momentum squared plus charge squared. The article suggests that to destroy the event horizon, you need change the BH's angular momentum or the charge. Because of the squared terms in the equation, that means you need to bring them closer to 0 (if it's positive, subtract, if it's negative, add). You can try to change the momentum by moving it or throwing something into it, or you can take the relatively simpler option of changing its charge. You could get electricity out of another black hole and feed electrons into it if its charge is positive (electrons are negative), or take electrons out if the charge is negative. Then, once the right side of the formula is greater than the mass, the event horizon will disappear and something will happen. No one is sure what will happen then, but you could claim that after testing, scientists found that it neutralizes the BH. You already said that you had a way to get energy from black holes, so you can probably fit this into your story. Maybe black holes have to be "charged" with electrons before a trip so that they don't collapse. That would make for some more interesting situations. What if the BH's power runs out and it needs a jumpstart? Why not have a BH with a positive charge so you can always draw power from it but need to give it a ton of e- to deactivate it because you have taken so much out? Hope this helps! [Answer] # [The Black Hole Bomb](https://en.wikipedia.org/wiki/Black_hole_bomb) > > A black hole bomb is the name given to a physical effect utilizing how > a bosonic field impinging on a rotating black hole can be amplified > through superradiant scattering. > > > I understand that's hard to read, and pretty meaningless. Can I recommend you check out [this video by Kurzgesagt](https://www.youtube.com/watch?v=ulCdoCfw-bY) In short, what it describes is a system by which we can harvest energy from a black hole, and if we never release that energy it will eventually explode in one of the largest explosions any civilisation could hope to create. I see no reason you couldn't apply the same principle for your engine, if you're drawing energy from a black hole, all you have to do is close the box and let it overwhelm itself. [Answer] **The Twin Singularity Engine** Adding to John Locke's answer. Conceive that your engine is powered by the difference between to oppositely charged singularities. The failsafe is to bring (crash) them together thus diffusing both. Great care should be taken to keep their charges in sync so that a failsafe action would leave nothing behind from one or the other. [Answer] Strictly speaking singularities probably don't exist. They are a mathematical anomaly. In reality Hawking radiation dissipates the mass of the black hole before the final collapse into a singularity can complete (from outside the event horizon the process is slow, trillions and trillions of years, from inside the process is nearly instantaneous). However a small black hole (1 million tons and smaller than a grain of sand) would be a wonderful source of energy. Although it would probably be easier to manufacture them rather than harvest them simply because the universe would have to be really really really really old for small black holes to exist naturally. A black hole small enough to be portable and also useful enough for energy production would emit so much outward radiation pressure that you wouldn't have to worry about a tipsy passenger falling into the event horizon. Black holes are incredibly stable, except at the very end of their lives where their radiation production increases explosively. You could stabilize your black hole by feeding it mass (assuming you had a way of forcing mass through the radiation pressure). This would be a slow process at best (if you could feed it fast enough at all) and would require hundreds of thousands of tons of disposable mass. Ejecting the black hole is the second best option. If you could eject it at a significant fraction of c you could buy yourself plenty of time before the boom. The best option is to not drag around this heavy and caustic black hole in the first place. Use an energy ansible between your ship and the black hole. The black hole is safely isolated and you have the option of shutting down the umbilical in the event of a catastrophe. [Answer] There are three main ways you can extract energy from black holes: accretion disks, superradiant instability, and Hawking radiation. In the first case you drop matter into the disk and gain energy from the radiation: the energy gained is proportional to the mass of the black hole so it favours large black holes. This is unlikely to be very effective for spacecraft, but I do recommend it for running large static installations. [Superradiant instability](https://arxiv.org/abs/1501.06570) basically extracts energy from the rotation of the black hole (it is somewhat related to the [Penrose process](https://en.wikipedia.org/wiki/Penrose_process)); this can give a lot of energy fast, but the black hole needs to be near-extremal - presumably they are created spun-up when inserted in the ship and used black holes spun up at local starbases. Finally, there is Hawking radiation which scales as $\propto 1/M^2$ - the smaller the black hole the more power you get ([there are theoretical ways of boosting this](https://arxiv.org/abs/hep-th/0012260)). So this favours very small black holes (good for spacecraft) but unfortunately over time they grow hotter and harder to feed matter to keep cool. So this is a plausible failure mode for a black hole generator. **Fortunately there exists a very simple solution: throw a bigger black hole on the failing black hole.** This "douses" the Hawking radiation by increasing the mass of the merged black hole, and it can now be disposed of responsibly. So I suggest that there will be an extinguisher black hole stored on the ship, used to get rid of engine failures. It is too large to have much Hawking radiation and doesn't rotate so there is no superradiance - indeed, it brings down the spin a bit. The main problem may be to move the extinguisher black hole fast enough in a crisis. Superradiant instabilities occur over a few light-crossing times in the tank you are keeping the black hole, so detection of a fault and dousing needs to happen near lightspeed. A slowly ramping up Hawking-radiator gives plenty of time to act. The gravitational waves of the in-spiral are likely to be disruptive only for about 100 times the Schwarzschild radius, so for small holes this will not damage the ship. [Answer] What if you used science B.S. to somehow increase virtual particle emergence around the horizon to evaporate the black hole far faster than normal and vent the hawking radiation out? Maybe as a side-effect the vessel gets a giant boost of speed from the blast that you could work into the idea. Also what if the black hole in the engine requires maximal entanglement with a second black hole stored safely elsewhere, and through more science B.S. you can safely dissipate the one by doing something with the other? What if this process isn't foolproof and sometimes it results in some or all of the vessel ending up at the location of the other black hole? ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 1 year ago. [Improve this question](/posts/223612/edit) In my story there's a family which only refers to themselves by their last name. They only go by their first names when in company with other members of their family, but even then they tend to use a pet name. The only way to actually know their name is by marrying into their family (besides being their doctor or something like that). But besides that they make sure that only people in their family know their first names. [Answer] In several cultures there are myths associated to people's names. From [Wikipedia](https://en.wikipedia.org/wiki/True_name): > > In Jewish tradition, when several children have died in a family the next that is born has no name given to it, but is referred to as "Alter" (Yiddish: אלטער, literally "old"), or Alterke, the view being that the Angel of Death, not knowing the name of the child, will not be able to seize it. > > > Generally speaking, it was believed that **someone could get some degree of control over someone else if they knew that person's name**. In the most extreme of cases, they would be able to take their life away. For further reference, there are quite numerous examples of folklore, pop culture and fictional works in the Wikipedia article linked above. [Answer] Judging by the time you asked this question, I'm guessing you're somewhere in the Americas where it's unusual to be known by your surname. Now the British are waking up we'll tell you it's entirely normal to be known primarily by your surname, or some familiar name based on it. Whether at school, at work, or among friends. Between one thing and another, it's reasonable not to know someone's actual first name. (Even him, his first name isn't Boris, that's his stage name) [Answer] The Romans did this, but the Romans had a messed up naming system. There were only 40 first names (praenomen) typically given to a male Roman. As time went on, it narrowed to about a dozen. So in public life, calling a Roman by their first name Decimus doesn't even make sense, because 1 out of every 20 people were named Decimus. So the given name was only used within the family. Also females were not given a (first praenomen) name. They only had a last name, with a feminine declension. So, let's use Julius Ceasar as an example. Hold on for it. His name was Gaius Julius Ceasar. Gaius was his praenomen which is one of the most popular praenomens and we don't know him as Gaius. He was in the Julia gens, so his nomen was Julius. His family line had a cognomen Ceasar because some ancestor of his had a caesarian (latin for the verb to cut) birth and adopted it as a cognomen pasted down to his descendants. His father and grandfather were named Gaius Julius Ceasar. His uncle was named Sextus Julius Ceasar and his aunt was named Julia Ceasar. He had a sister named Julia Ceasar and another sister named Julia Ceasar. They were referred to as Julia Major and Julia Minor. His daughter, who married Pompey, was named Julia Ceasar. I'm not suggesting you follow this wacky system, but I am saying in history there are cultures which do not use given names. You can have such a culture in your world and not worry about having to justify the verisimilitude. [Answer] It is entirely possible for people to be known by their family name and a nickname. In some parts of the world, family names precede given names due to the importance that family names have over personal names. Consider the novel Dune by Frank Herbert. The protagonist, Paul Atreides, is adopted into a clan of Fremen on the planet Arrakis. Fremen custom is for individuals to have a public name that the individual chooses for themselves, and a private name, which only those closest to the individual may know or use. Paul Atreides is given the private name Usul (meaning the base of a pillar), and chooses the public name, Paul Muad'dib... but the Fremen eventually drop 'Paul', and call him simply Muad'dib (the name of the hopping desert mouse). Even in real world cultures, there are names that are restricted. In some modern Islamic societies, women may have given names that only their family or another woman may know, that no male stranger is permitted to know. So, for a given name to not be known even if its owner is well known isn't anything particularly unusual. [Answer] **Since no species/context was specified, I'm going to assume that they're on a human inhabited planet for the purposes of reconnaissance/surveillance.** Take that as a frame-challenge if you will. Their species doesn't have individual names, they identify solely as members of their swarm. They are a hive-mind that lacks differentiated identities or fixed functions within the group and arrive at decisions almost by reflex of consensus without debate or equivocation. They are also shapeshifters, taking the form, clothing, voice, name and character-role of their chosen family member only in company when they imitate flawlessly all regular human habits and appropriate idiosyncrasies enough to seem like regular folks. [Answer] **Their first names are all very silly.** [![drag nutts nickels](https://i.stack.imgur.com/O9Efn.jpg)](https://i.stack.imgur.com/O9Efn.jpg) [source](https://www.reddit.com/r/SouthDakota/comments/s36kp2/someone_in_butte_county_wants_to_change_their/) Rogue Lawyers with sophomoric senses of humor have changed the first names of all these people to silly strange and obscene things. Some of the new names are also extremely long. Some are invented symbols. Some are sound effects. All of the sound effects are fart noises. It is all perfectly legal but the family usually works around it. [Answer] **Monarchs and Nobility** If your name is on [this list](https://www.scarymommy.com/royal-last-names/) announcing that you are part of that family is probably more important than your name unless you are famous in your own right. If your last name has been changed to Caesar this also applies. Any name that is changed for religious/political reasons falls under this umbrella also [Answer] Use of surnames is pretty normal, with or without title. To me it seems odd that I even know my child's teachers' first names, when I'd always refer to them by their chosen title (usually Mr. or Mrs.; Ms. is fairly uncommon) and surname. Nicknames are also common, as is a complete mixture. In one club, we have: * a duplicate first name known by a nickname unrelated to his name (animal-based FWIW - he often greets male friends by surname alone. Hearing my surname bellowed from a distance does transport me back to school sports though. * one member commonly known by his surname * another who uses first name and abbreviated surname, but whose son is almost invariably known by a nickname * another parent known in some contexts by his self-employed business/work name, with a child referred to by a diminutive of that. You might also look to the names people choose for themselves here, on Twitter or Strava (not so much Facebook with its real names policy) - somewhere between a nickname and a personal brand. These can be completely unrelated to their real name. If I met any of those in person, I'd call them by their adopted/screen name. To use an example from here, this answer started as a comment on @separatrix's answer. I'd hazard a guess that's not their birth name. I suspect you need to use the family name with a nickname to be more specific. The tricky bit is taking on that nickname from a young age - they might start off as "Baby Smith" but become "Broccoli Smith" after that time when they chucked unwanted food at a grandparent. That may or may not stick. ]
[Question] [ Working on a sci-fi project, similar to well known properties, in which real world road maps play a role, but need to justify them in world on a planet where people don't build on the surface. I have entertained the idea of 1. septarian nodules: rock formations that resemble roads. 2. An extinct ancient civilization whose roads persist. 3. laser projections showing 'safe paths' None of these quite work. Does anyone know any other reasons why roads or road like formations might appear on a planet's surface? The planet is a remote, outer rim space pirate haven loved also by the cartels for the presence of a rare mineral that is created by some of the local fauna. Said fauna prevent people from settling on the planet's surface, and yet there are 'roads' present. Desert in appearance, and made nearly inaccessible by an asteroid cloud. [Answer] **Animal trails.** [![animal trails](https://i.stack.imgur.com/UWfxS.jpg)](https://i.stack.imgur.com/UWfxS.jpg) <https://www.tripadvisor.com/LocationPhotoDirectLink-g60857-d102614-i133670350-Hovenweep_National_Monument-Cortez_Colorado.html> Animals will often stick to trails. It makes sense in a place with a lot of brush or with uncertain depth of snow or water - if you walk where other things have walked it might be easier. The depicted trails though offer no particular advantage except they might be the shortest path. Large animals can make large trails. One can find a lot of copyrighted photos of the Okavango delta where elephants and hippos make big trails that are then used by other animals. I read that in the late 1700s there were well beaten trails to salt licks in Kentucky - at that time in use by bison and smaller creatures but used farther back by Pleistoscene megafauna like mastodons. These beaten paths were often the ancestors of roads - they are easier for humans to take too although not necessarily the shortest route between A and B. There is a great poem about this for those inclined: <https://poets.org/poem/calf-path> In any case - your "roads" are the ancestors of our roads. Calf paths. [Answer] ## Ice ridges [From a body such as Europa](https://www.jpl.nasa.gov/images/europa-ridges-hills-and-domes). In this figure the features are 200 yards per pixel, so these are unusually large "overpasses", but you could handwave about different conditions of gravity, tide, water temperature etc. giving to-scale results. [![Europa ice ridges](https://i.stack.imgur.com/8rQLG.jpg)](https://i.stack.imgur.com/8rQLG.jpg) [Answer] Don't bother to explain them. [Chekhov's Gun](https://en.wikipedia.org/wiki/Chekhov%27s_gun) suggests that unless the explanation is important later in the story, don't bother burdening the audience with it. Here's an example of something relevant to your question that is never explained from Arthur C. Clarke's [Childhood's End](https://en.wikipedia.org/wiki/Childhood%27s_End) (1953) > > And far, far away on the horizon was something that was not of Earth-a line of misty columns, tapering slightly as they soared out of the sea and lost themselves among the clouds. They were spaced with perfect precision along the rim of the planet-too huge to be artificial, yet too regular to be natural. > > > You can see that in this case the author was *deliberately* ambiguous about the origins. Maybe your patterns are roads, maybe they are not. Maybe your characters simply don't know their origin. Maybe some cultures take them for granted. Maybe other cultures worship the "path-makers." And other cultures deny the patterns exist at all. And yet other cultures labor to eradicate the ancient evil of the "devil roads". Perhaps mad scientists claim (falsely; they are mad) to know the truth behind the enigma. And perhaps the poets --who claim them to be a work of art-- are closer to the truth than anybody else. Wash your hands. It's time for dinner. [Answer] Depending on how much water is now present on your planet (you mentioned in the comments that the planet is currently desert-like), dried out rivers like those which appear to be on Mars could create something like road networks. [![Mars river beds](https://i.stack.imgur.com/seeNp.jpg)](https://i.stack.imgur.com/seeNp.jpg) Image from: <https://www.esa.int/Science_Exploration/Space_Science/Mars_Express/River_relic_spied_by_Mars_Express> [Answer] > > Walk without rhythm, it won't attract the worm > > > In the Dune series of books, there are giant worms that traverse the world a la graboids. They are called 'sandworms' and you can read more about them [on the fandom wiki](https://dune.fandom.com/wiki/Sandworm): > > Sandworms lived beneath the sand. Attracted to rhythmic vibrations on the surface, they would breach in pursuit of the origin of such vibrations. This was an effort to defend their territory, of which they were highly protective. Thus to see a worm, and live to tell about it, was extremely rare, save for the mysterious fremen, who had achieved some kind of mastery over the beast. > > > (...) > > > Their skin was thick, rough, and orange colored. It served the simple function of armor and was comprised of many scales, each a few feet in size. These scales overlapped and interlocked to form the armor that protected it against internal sand invasion. > > > As the Fremen discovered, this armor, while all but impenetrable, could be exploited. By prying open the edges of one or more of the scales, the integrity of the armor would be compromised; sand was now free to enter into the sandworms softer insides. This would cause intense irritation for the sandworm. The beast would then roll itself until the prone scale was at the highest point from the desert floor, thus minimizing the amount of sand that could enter. > > > A fremen poised to "ride" the beast as it rolled its open scale towards its highest point could literally mount the worm. As long as the scales remained open, the sandworm would not submerge. Maker hooks were then placed towards the front of the beast to control lateral movement. As a result, wormriding became a viable, even sacred, method of transport for the Fremen across the surface of the planet. Indeed, distances were even measured in "sandworms", the distance one could ride a worm until it was exhausted and allowed to submerge. A 20-worm ride would be a far and difficult journey. > > > Some worms in the books are 450 meters long (a bit over a quarter of a mile). Any being that large that spends its time tunneling through the earth close to the surface will leave marks. In fact the ground is very likely to collapse around those tunnels; if the collapse is either shallow or old then the worm's trail would look different than its surroundings, effectively looking like a primitive road if seen from afar. [Answer] Well then, my friend, I have my answer, from the writings of Phillip Pullman. You see, he had the same problem with his natural roads, and as an answer, lava flows. If you can explain a peculiar amount of volcanic activity, then you could easily say that these roads are simply cooled down remnants of lava flows. [Answer] Sailing Stones (<https://en.wikipedia.org/wiki/Sailing_stones>) are one option. These are stones which move around on a flat, flooded surface such as a desert floor, when the conditions are right (high wind, freezing temperatures). They leave behind trails as if the rock had dragged itself. Since they're driven by Ice Shoves (<https://en.wikipedia.org/wiki/Ice_shove>) there's a limit to the size of the rocks involved, but having some large enough to make a reasonable road-sized line should be possible with rocks wide and flat enough. It just needs a large enough ice surface floating over the water and shoving the rocks. [![enter image description here](https://i.stack.imgur.com/eAjnt.jpg)](https://i.stack.imgur.com/eAjnt.jpg) [Answer] If you specifically want natural structures that resemble modern paved roads, you could use lava flows. Under the right conditions, volcanic rock can be quite similar to asphalt. [Answer] How about... optical illusions and telescopic artifacts? Just referring to <https://en.wikipedia.org/wiki/Martian_canal> At the end of the 19th and in the beginning of the 20th century, it was believed that Mars had canals, because long, elongated structures were seen on it's surface. It turns out that this was a combination of wrong translations of the word 'canali' in combination with bad lenses (well, worse than we have today, anyway) and the cognitive effect that our mind wants to see patterns — even if there are none. I for myself find this a fascinating story. I do not know how this could fit into your project, but I would just like to offer a non-material alternative to the other proposals. [Answer] Imagine a small plant, similar to grass, but has a root structure that stops any other plant life from growing in its vicinity. Perhaps the roots emit a certain kind of poison , toxic to other plant seeds. Animals will naturally make tunnels through underbrush, and while doing so, they will gather some of the seeds of this plant on their fur. As they travel along the paths that they make, the seeds will fall off along the way, taking root and driving out other plant life. Animals clear out the underbrush by breaking it apart as they move through it, and the plant makes it so that no new growth takes its place At first, the plants might not make that much of a significant difference to how clear the path is, but as more and more animals take the same path, they spread more and more seeds along the same ground and clear out more of the other plants that grow along the side of the path. This benefits the animals, by giving them easy transportation, and it benefits the plant by spreading its seeds along new paths. Over time the most widely used pathways could become long, twisting stretches of green carpet, cutting through dense forested area, with smaller pathways diverging away from them like a natural highway system. This theoretical plant does not take over the entire world because of the fact that it is relatively weak, and relies heavily on animals constantly replanting it and maintaining the roads. [Answer] Well based on your comment about it being a mining planet would ore veins work? It may not be super realistic with earth ores but with different geologic conditions i see no reason why an ore could not have a spiderweb of veins close to the surface. ]
[Question] [ **Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/229631/edit). Closed 1 year ago. [Improve this question](/posts/229631/edit) The Vareyn once lived in a fertile land at the head of a great desert, subsisting off of a great river and its bounty - until they were forced to leave after a catastrophic volcanic eruption. Many years later, the Vareyn had long moved on to become a seafaring civilization, and after the ash had settled, a new people came to fill their place. My question is, would these new settlers adopt parts of the Vareyn language? I imagine that, since the material culture of the Old Vareyn people remains, there would be a considerable collection of cultural artifacts (like literature, inscriptions etc) that would become part of these settlers' vast inheritance. Realistically, though, would this influence these people and the evolution of their language specifically? Thanks for any help you can offer! [Answer] Previous answers have dealt with the question in its narrow form, but this could be treated as an instance of the more general question: when people are surrounded by multiple languages, how do they decide which one to speak? If people are surrounded by a language that exists *only* in written form (as in medieval Egypt), then they won't adopt that language for obvious reasons. However, it is not unusual for cultures to prefer entirely different languages for writing and speech, which sometimes includes using a "dead" language for writing. For instance, medieval scholars generally wrote in Latin, while the Christian apostles, and Roman philosophers like the emperor Julian, wrote in Greek (according to Gore Vidal, sophisticated correspondents in Julian's time considered Rome's own language to be an inferior option more suitable for bureaucracy and commerce). Another common pattern is that when large numbers of cultures coexist, as in the Roman empire or modern India, they will settle on a common written language because literacy requires a lot of training anyway, and if you're going to make that investment it is more profitable to learn to write in a language that a thousand times more people can understand (like Latin, or Hindi, or English). And that language might then seep back into their native speech, albeit rarely replacing it wholesale. The main reason people adopt a foreign written language is commerce (or political force, which is kind of the same thing). But the popularity of written Greek in the early Common Era seems to have been more due to the high regard for existing Greek literature. And modern Greek is partly the result of a conscious effort to resurrect the classical language. So you could imagine something like that happening with Vareyn, if the settlers brought a wide variety of native languages with them, and Vareyn literature was considered especially good. **But,** only if actual Vareyn *speakers* were widely available the whole time. No one goes out of their way to learn a new, long-dead language just to use it to buy cheese in their own village. [Answer] You would not expect any influence because as you describe it there is not any cultural or historical relationship between those two peoples. Literature for example is not "left behind", it is actively transmitted and translated between cultures who are in contact. Stone inscriptions and the like will not influence the language of the newcomers who cannot even read them. You can of course construct a situation where such an influence takes place if you want to. Maybe the newcomers find a library of the Vareyn in the desert sand, their scholars *somehow* figure out their language and it turns out that those Vareyn knew a lot of things the newcomers do not know - in subjects like astronomy, medicine, mathematics etc. In such a case the language of the newcomers would probably adopt scientific vocabulary from the Vareyn. [Answer] Language is not a biological agent which remains active after the bearers are gone. If it is not used in life, it cannot be transmitted. Look at Latin: though inscriptions in Latin were present in Rome and all the territories if the empire after its fall, hardly anybody without an education would speak Latin, using vulgar. Even less in parts like modern North Africa, Turkey, Greece, middle East and so on. Actually, I remember reading that in a Pompeii graffiti they found an inscription which sounded more close to the current dialect than to classical Latin: the writer had written "I want to give you a kiss" using, instead of the Latin osculum, the dialectal vasum. [Answer] **Not a slightest chance** In your case there is a very clear discontinuity between speakers of the old language and new settlers. Only written texts remains, and phonology of the old language just can't be reconstructed. If new people have interest in the old text AND those texts have strong similarity to the other language that they know, or they are lucky to find a [Rosetta Stone](https://en.wikipedia.org/wiki/Rosetta_Stone) which provides a link between the old language and the language that they know, then old text can be translated. But this will be a translation only - without revival of old phonetics, sounds of words of that language would remain lost forever. P.S. I presume that both old and new civilizations are pre modern. If (like @Daron implied) old civilization left audio recordings of their speech, old language could be revived. [Answer] **Nope** The settlers move into the ruins of Vareyn civilisation. There are arches with inscriptions and libraries full of books. The settlers cannot read them because it is a different language. It would take decades to reverse engineer the language and there is no obvious benefit. **Unless. . .** There IS some obvious benefit. For example the Vareyn had better metalworking technology. Their spoons and geodesic domes are built from some strange rust-resistent alloy. In that case the settlers' scholars spend ten years trying to read a metalurgical textbook from context, and piece together a lot of the language from there. This leads to a lot of Ancient Vaeryn becoming technical terms in the sciences. Or maybe they all had smart homes (yuck). All the houses are solar powered; there is food in the fridge; but you have to speak Ancient Varean to open the door. [Answer] # Best example: Egypt Egyptian old dynastic pharaohs had many edicts written in hieroglyphs. By the younger dynasties, the edicts were using shorthand cursive. Then the Achaemenid Persians came (twice!) and brought a different script and then Alexander came. Shortly after, things were written down in greek, then the script changed again (to Latin) when it became a Roman province, then a variant of that, then the Sassanid Empire conquered it, demanding its own script, and then came the time of Islamic rulers, again overthrowing the writing system and language. 3000 years of language changes, in a nutshell. By 680, nobody in Egypt or anywhere spoke old Egyptian or could read hieroglyphs anymore, and even the cursive and Achaemenid Persian were unreadable or had speakers. Only some dialects of Greek, the Church Latin, and the Sassanid dialects were used somewhere and their scripts readable by someone, but people in Egypt would shift to speak and write what we call "Arabic" today. So, to boil it down: No, even with a takeover, it is common that the new masters bring their own language, and if there is no contact between the old inhabitants and the new inhabitants, then there is no cultural transfer of language and thus they will bring their own language. [Answer] > > Many years later, the Vareyn had long moved on to become a seafaring > civilization, and after the ash had settled, a new people came to fill > their place. > > > By this passage, it can be assumed that the two civilizations are still co-existing. The Vareyns still exist as a civilization, with all of their cultural bag and baggage, language, and iconography, they have just moved on to another habitat. Unless the two civilizations were an entirely different species, and communicate in a completely alien fashion to each other, the interplay between the languages is inevitable. Vareyn artifacts will still have to be named by the newcomers, and it is inevitable the names will be based on the original terminology. It is equivalent to the white race pretty much forcing indigenous societies out of their lands, but elements of the original indigenous language live on in the manes of places, and artifacts. As long as two civilizations co-exist, their language will intermingle. [Answer] **The new people were longtime admirers of the old.** [![double headed eagle](https://i.stack.imgur.com/z30g3.png)](https://i.stack.imgur.com/z30g3.png) > > So know, pious king, that all the Christian kingdoms came to an end > and came together in a single kingdom of yours, two Romes have fallen, > the third stands, and there will be no fourth... > > > <https://en.wikipedia.org/wiki/Moscow,_third_Rome> The people who now inhabit these lands did not come a long distance to settle here. They lived in the hinterlands and barbarian areas around the Vareyn homelands. They raided the Vareyn, or were employed by them, or enslaved by them. They were very impressed by the Vareyn and rightly so. They are to this day. These people have repaired the Vareyn buildings. They emulate Vareyn society. They assert that they speak Vareyn. They say that they are Vareyn. No original Vareyn are around to disagree. [Answer] You've got the serious (and correct) answers, so I'm just going to abuse the fact that you didn't specify the technological level that the Vareyn had reached before sailing off to sea. ## Yes, but they don't understand it The Old Vareyn ruins are complex and full of marvels. Over the years, the bravest of your people have dared to explore the crumbling towers, labyrinthine tunnels, vast plazas and majestic palaces. What they found was, by any definition, magic. Doors that open themselves, stairs that move, magical mirrors that show moving images from far away. And - voices. Some are activated by pressing a button, others just by standing in the right spot. Some have been looping forever. Some have now stopped, but your sages have recorded them. Your people understand that these are the voices of the Gods. They sing the looped recordings as chants to Myne D'hgap, goddess of the underworld, not knowing their meaning, but feeling their power in repetition. They recognise some as warnings or omens, because when One-Armed Lynn tried to stick her hand through the doors, the voice came and she acquired her nickname. Out of narrative, the only way they would include the previous civilization's language is if they could hear it. If the Vareyn are gone, the only way is audio recordings. Without actual two-way communication, they would not understand what these recordings *mean*, but they could still use them for ritual purposes - this was the status of Church Latin for most Catholics until the Second Vatican Council. Individual snippets (they may not be able to identify which sequence of sounds is a single lexeme, so it may not be something a Vareyn would recognise as a word) may be incorporated in their language as names, invocations, curses etc. The overall sound of the language may affect theirs in terms of phonemes, but only if enough people actually get to hear the original audio. The grammar and language structure would leave no trace whatsoever. [Answer] > > The Vareyn once lived in a fertile land at the head of a great desert, subsisting off of a great river and its bounty - until they were forced to leave after a catastrophic volcanic eruption. > > > Many years later, the Vareyn had long moved on to become a seafaring civilization, and after the ash had settled, a new people came to fill their place. > > > My question is, would these new settlers adopt parts of the Vareyn language? > > > **Maybe.** Probably not, but it really depends on how we fill in the gaps in your scenario. (FWIW, that's one reason why you're getting so many different answers.) Newcomers to a land borrowing words (and expressions and phonetics and even grammatical features) from the language of the people previously living there happens all the time. Linguists even have a term for it: [substrate influence](https://en.wikipedia.org/wiki/Stratum_(linguistics)). But normally that happens *while the people speaking the old language are still there*. If the previous inhabitants are gone entirely, e.g. destroyed or driven far away by some catastrophe, then it's unlikely that just the inscriptions they left behind will have much effect on the newcomers' language, especially if most of the newcomers can't read them. Even if some of the newcomers do have the motivation and skill to decipher the old inscriptions (rather than just treating them as decorative art, or as evil heathen marks to be destroyed, as seems to have been common in real life), they'll probably just translate them into their own language. Sure, you *might* end up with a handful of borrowed words for otherwise untranslatable technical or cultural terms, but probably not much more than that. Things might be somewhat different if the two languages happened to share the same writing system, and if literacy was common enough among the newcomers, that most people finding the old inscriptions could actually read them. In that case you *could* perhaps get significant borrowing, especially if the two languages happened to be so closely related as to be at least somewhat mutually comprehensible. On the other hand, if the new language was unrelated to the old one (but still sharing the same writing system), it seems more plausible that the old inscriptions would just seem like gibberish to the newcomers. Now, a common human reaction to seeing something unreadable but clearly meaningful carved in stone seems to be "It must be magic!" So a plausible outcome of this particular scenario could be a bunch of words from the old language being adopted into the new one, but with *completely different meanings*, as people claiming (falsely) to be able to understand the old language would pick more or less random phrases from it and use them as "[barbarous names](https://en.wikipedia.org/wiki/Barbarous_name)", inventing new mystical meanings for them. --- But of course, none of those scenarios really match yours in one respect: your Vareyn people are still alive, although living in completely different region and with a different lifestyle. That, in turn, raises a bunch of questions: * Did any Vareyn remain in the old lands, or return there after the catastrophe? If not, why not? (It's rare for people to *entirely* abandon a land, as long as as it's even marginally livable and as long as they're not forced out of it by other people moving in.) * If all the Vareyn left, did they move far away, or did they stay close enough that the new people settling their old lands would know of them? (And, if the latter, why didn't the Vareyn themselves resettle the old lands once it was possible again?) * How much of their old culture and language do the new "sea Vareyn" retain? Can *even they* read the old inscriptions, or understand the old Vareyn language? Do they even know where their old homeland was? If some descendants of the old Vareyn did stay in or near the old lands, or return there once the worst of the catastrophe was over, that could provide the kind of linguistic continuity needed for a proper linguistic substratum. It doesn't really matter if there are only a few of them — all that's needed is that they're there, and they they can read the old texts in their own language and teach that language to the newcomers. On the other hand, if the Vareyn moved far away from their old homeland, it's possible that the newcomers might not even know that the Vareyn still exist somewhere. In which case it doesn't really matter whether they do or not, as far as the newcomers are concerned. Indeed, if enough time has passed, even the Vareyn themselves might have forgotten exactly where their old homeland was, and their culture and language could easily have changed beyond recognition. They might not even be able to read the old Vareyn inscriptions themselves, e.g. if they ended up adopting a different writing system from some other culture in the mean time, or if literacy among the old Vareyn was restricted to, say, a particular priestly class that no longer had any meaningful social role in their new lifestyle. And the new Vareyn language could also be heavily influence by a substrate language spoken by whoever used to previously live where the Vareyn moved to. *Someone* almost certainly already lived there, and that's probably who the Vareyn learned their new lifestyle from, one way or another. Most likely that learning would come with a heavy dose of linguistic borrowing, as the Vareyn would need huge amounts of new nautical terminology (boat/ship types, ship parts, crew roles, sailing tasks and commands, directions, points of sail, terms for nautical geography and weather and winds, types of fish and other marine life, new foodstuffs, etc., etc.) that they wouldn't have needed before. Or the Vareyn might even have given up their old language entirely and switched to a different one spoken in their new homeland, maybe with a bunch of substrate vocabulary and phonetic influence remaining from their old speech. --- Anyway, assuming that your newcomer people *do* somehow end up in sufficient contact with the old Vareyn language to borrow parts of it, what would be the most likely things to be borrowed? Historically, the most likely remnants of a displaced and otherwise forgotten language to survive in a recognizable form are [toponyms](https://en.wikipedia.org/wiki/Toponymy), i.e. the names of places and geographical features. The reason for this is kind of obvious: when you move to a new land, you need *some* names to call the rivers and hills and valleys etc. there, and one of the most natural choices (especially if the particular feature you need a name for doesn't have a particularly distinctive appearance) is whatever the previous inhabitants called those things. Which might be whatever the *previous previous* inhabitants called them, and so on. Of course, it's also likely that any such borrowed geographical names will be modified to fit the new language, and maybe even given new [folk etymologies](https://en.wikipedia.org/wiki/Folk_etymology) and "corrected" to better match them. At the very least you're like to see the old names attached to a descriptive suffix (or prefix) like "town" or "river" or "hill" etc. in the new language. Personal names are also fairly likely to survive, although a lot of that depends on the naming habits of the new culture. (If personal names in the new culture tend to be descriptive phrases, they're a lot less likely to adopt names from another language than if they have a tradition of "opaque" names with no obvious surface meaning being passed on from generation to generation.) A third common category for borrowed words are terms for things that the borrowing language has no existing word for, such as types of animals or plants or terrain or weather that don't exist in their former homeland, or new technological, cultural, social or religious concepts. The latter category might include things such as professions, titles and military or religious ranks, as well as things like new foodstuffs, clothing items, tools, games, instruments, etc. Of course, the likelihood of all of these linguistics borrowings depends a lot on what kinds of cultural and technological aspects the new culture ends up adopting from the old one. Here, as in general, language tends to follow culture. Yes, sometimes even words for common and familiar things do get borrowed, especially if two languages are in very close contact. But borrowing is a *lot* more likely to happen when you need a word for a new concept that you don't have in your own language yet. [Answer] It may impact the culture, but not the language. Even if they were able to decode the Vaeryn texts and understand the meaning, that would provide no indication as to how the words were spoken, unless the two languages share the same written characters, and interpret those characters in the same way. The settlers would ultimately use their own language when describing Vaeryn cultural artifacts, and no element of the Vaeryn language would be reconstructed (for a real life example, how much do you see "Linear A" script or "Indus" script impact modern languages). If they share similar looking characters but not pronunciations, the result may be like an English speaker trying to read Cyrillic by substituting the sound of whatever letter looks most similar. Something might get incorporated into the settler's language, but it wouldn't necessarily sound anything like the original word. If they share a phonetic written language and there hasn't been too much linguistic drift, it would be possible to reconstruct the pronunciation of Vaeryn words, and they may then be incorporated into the settlers' language. However, in that case you are probably talking about two closely related languages used by closely related cultures. How much would these ruins teach them that they haven't learned directly through exposure? Culturally, the remaining Vaeryn ruins might inspire the settlers' architecture, or they might simply like the look of Vaeryn text and use elements of it for decoration. Similar to how, in real life, it's not uncommon for someone who doesn't speak Japanese to get a phrase tattooed in kanji. Technology might get rediscovered if the settlers take the time to figure out what it is and how to use it, but it might also get repurposed. Metal tools may be melted down, stone blocks stolen and used in new buildings, paving stones relocated onto new roads. The finished product merely indicates that something is possible to construct, it doesn't necessarily provide the information one would need to duplicate the feat. [Answer] They might take on some of their language in order to better communicate with other tribes, merchants, or people in neighboring countries, if the original inhabitant's language was known and the new inhabitants language wasn't. Like how many African nations found that knowing English was useful long after native English speakers left, because it was a common language that they could use to communicate with each other, or with people from far away who didn't know any African languages\dialects. You might also have situations where the newcomers were in awe of some aspects of the local culture and followed them in a cult like way. [Answer] Before this is closed. I want to squeeze in another factor to be considered, that complicates any answer. If the Vareyn culture and language was 'replaced' in this area by another different culture and language, it assumes there were at least two cultures that had descended from some common culture through evolution (unless they are a different species). This therefore assumes some common ancestry. It also presumes that the Vareyn peoples were not alone in their part of the world. With any sufficiently advanced culture, they would have traded with societies around them. This would have necessitated some form of mutual common communication. Even if the Vareyn completely left the area, their influences on their neighbours would still remain. A case in point is the Rosetta stone. This stone was created for a reason - the original intention was to link three languages and cultures together, because there was obvious intermingling between them, undoubtedly promoted by trade. It was created when all three languages were active, and all three societies were intermingling. There are very few 'pure' languages on Earth that have not been influenced by antecedent languages in their development. As a frame challenge, any answer would depend on how the Vareyn language originated, and on how widely it was spread to neighbouring societies while the Vareyn were in the neighbourhood. If the Vareyn peoples were numerous, they would most certainly have had 'branches' that spread throughout the region. In point of fact, it is not beyond speculation that the newcomer language could probably have been influenced by the Vareyn language, and vice versa, even while the Vareyn were still inhabiting the region. It is very rare that any population develops in complete isolation, unless it is, well, completely isolated by geography. And that is a plot point that is not specified in the original question. [Here](https://en.wikipedia.org/wiki/Zoroastrian_Dari_language) is an example of a language that has descended from other languages, morphed into its own distinct language, and is now almost extinct. > > Genealogy Genealogically, Dari Persian is a member of the Northwestern > Iranian language subfamily, which includes several other closely > related languages, for instance, Kurdish, Zazaki, and Balochi.[6] > These Northwestern Iranian languages are a branch of the larger > Western Iranian language group, which is, in turn, a subgroup of the > Iranian language family. > > > ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- Closed 2 years ago. * You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). * This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). [Improve this question](/posts/201079/edit) During excavations some wizards came upon the workshop of the 5th dimensional being that created everything, essentially god. In that workshop were many notebooks chocked full of the techniques of creation (Turning 5th dimensional magic energy into 3 dimensional objects) Every once in a while godly existence gets boring and you need to spice things up, so some notebooks contained various ways of destroying things. Over a few hundred years our intrepid wizards translated one such way. It involves dropping something. Luckily wizards have access to airships with a ceiling of 5000m. Rules: 1. It can be any currently known natural substance or substances in our world even if the wizards have no idea what it is. Natural is key. Avoid Man-made substances/chemicals. 2. The least complex the better. 3. No nuclear bombs, balls of pure gunpowder, or metal spheres filled with nitroglycerine. (See #1 on man-made) 4. It must fall a minimum of 300meters and a maximum of 5000. 5. Weight limit: Don't drop a mountain on the town. 6. The wizards should be safe from the resulting destruction. (Most of the time. Some of the larger craters will have definitely destroyed the wizards who made it.) 7. It must be scalable. The God-creator used it to make a 800km diameter crater. The wizards will use it to make craters between 100m and 15km. 8. When the wizards are “creating” the object it will be stationary and inert. Once their spell is complete it will become “fully real” and any chemical reactions will begin. 9. The wizards need to be within 30meters of the object while creating it. So when it is “fully realized” the object must not instantly kill them by its proximity. 10. The object created is permanent and must not cause undue devastation to the world beyond its initial impact. Notes:The object doesn’t necessarily need to be explosive, but I feel that’s the only way. I’ve done the math for the impact of a 100 ton pure iron sphere dropped from 5000m, but it doesn’t have nearly enough energy for what I’m looking for. I originally wanted the objects to be actual meteors falling from outer space or teleported into the atmosphere, but my magic system doesn’t really allow for that. There have been questions about medieval explosives, stone age explosive, and others, but I believe this question to be unique and not a duplicate due to the criteria. [Answer] Ever tossed a river rock into a campfire? Probably not -- camping seems to be restricted to those who are fanatical about it, these days, instead of being forced on clueless children. I mention this because a waterlogged stone will explode in a fire when it gets hot enough for the water trapped in the rock to flash into steam. People have been injured by this phenomenon with rocks the size of a fist. What your wizards need, then, is a source of heat that they can put inside a large, waterlogged stone (ideally one shaped so that when it drops, it'll penetrate the ground and spend its energy moving the earth rather than just spraying fragments of itself). Fortunately, any mixture of sodium, potassium, and lithium will do this, and provide a certain amount of delay to allow for the "bomb" to fall. If the wizards can't create alkali metals, they could accomplish much the same effect with sodium or potassium hydroxide (which will get very, very hot when it reacts with water in any form). Now, it would *take* a god to make a crater 800 km across this way -- but if you're willing to handwave that, the BLEVE type explosions these "steam rocks" can create might well produce shallow craters as large as several hundred meters across, depending strongly on the soil they're dropped into. [Answer] # You cannot simply "drop" something. If you can't drop explosives, you're left with plain ol' impact force. But nothing lighter than a mountain will do (in fact, it must be **much** heavier). You have imposed a vague weight limit: > > Weight limit: Don't drop a mountain on the town. > > > **Note:** I'm taking you at your word and treating this as a limitation on the mass of an object, rather than the size. You have imposed a specific height limit: > > It must fall a minimum of 300meters and a maximum of 5000. > > > You're asking for a crater about one tenth the size of the [Chicxulub impact crater](https://en.wikipedia.org/wiki/Chicxulub_crater), which is around 180km wide. It is estimated that the total energy of the Chicxulub impact was between $1.3×10^{24}J$ and $5.8×10^{25}J$. Now, there are various estimates of the exact relationship between crater diameter and the energy of an impact, but we know it is approximately $K\approx D^3$,[1,2,3] so if we reduce the diameter by a factor of 10, the energy is reduced by a factor of 1000. Therefore, we're shooting for **at least $1.3×10^{21}J$**. Now for why what you ask is impossible: A height limit plus a weight limit imposes an upper bound on the energy of anything propelled by gravity. Specifically, $E = \frac{1}{2}mv^2$, where $m$ is the mass of your object, and $v$ is the final speed of your object. What will be your final speed? With your wizards' magical ability to negate friction around their object, we will neglect air resistance. Now, we could calculate these integrals ourselves, but we're smart internet users so we can use [this free fall calculator](https://www.omnicalculator.com/physics/free-fall) to find a fall time from 5km of 31.93 seconds, giving a final velocity of 313.16m/s. This is the *maximum possible speed* given your height restrictions and allowing *zero air resistance*. Plugging this in to our kinetic energy expression, we can see that for the energy we want, our mass would need to be around $1.3\times 10^{16}kg$. Is that heavier than a mountain? The tallest mountain (from sea level) is Mt Everest. A nice back-of-envelope estimate at <https://weightofstuff.com/how-much-does-mount-everest-weigh/> gives a whopping 357 trillion pounds, which is $1.62\times 10^{14}kg$. **Even if we stretch the limits you gave to the extreme, we're still a hundred times too light for the crater you want.** ## So, what can we do instead? We've ruled out just dropping a thing. The size limit and speed limit make it impossible. You've ruled out making the thing heavier, so all that's left is to make it faster. **Don't drop it at the ground, *throw* it!** Take a 2-ton ball of steel and use your wizardly powers to impose a strong magnetic field to push it down to the ground. With arbitrary amounts of magical energy, your wizard railgun can make that ball go arbitrarily fast and pump as much energy into the crater as you want! References: 1. <https://www.noao.edu/jagi/sepo/education/plansurf/plansurfiiia.html> 2. J. W. Bond, The moon and the planets volume 26, pages317–321(1982). DOI: 10.1007/BF00928014 3. D. W. Hughes, Mon. Not. R. Astron. Soc.338,999–1003 (2003). [Answer] ## Sodium Sodium is a basic element that can be using for making bullets that explode violently on impact <https://www.youtube.com/watch?v=T85d7ST2yxU>. Because it is a pure element, it's composition could not be any simpler. I can't find any exact calculations, but if a simple handgun bullet can contain enough sodium to make things explode this dramatically, I'd imagine dropping a 100 ton ball of the stuff would produce a very impressive crater. Apart from being highly explosive, this solution is good because the fallout would quickly react with various elements in the ground forming common salts. While your target zone may be rendered agriculturally ruined for a few decades, it would not be so toxic as to be a threat to people settling the area thereafter. [Answer] I think a microscopic primordial black hole could more or less fit the criteria you give. Points in favour: * Certainly not man made (we can't make them!), * explosion by black hole evaporation can be precisely timed by setting the initial mass, * all of the intial mass is converted to Hawking radiation in the process, which gives a very significant release of energy even for the most modestly sized of black holes, * a sufficiently low mass black hole will have a subatomic sized Schwarzschild radius and negligible gravity over macroscopic distances, so before detonation, being within 30 metres of it should not be a problem, * and the amount of energy released can also be precisely controlled by setting initial mass, so we do have some degree of scalability! Now, given the size and density of the created object we can safely ignore any interaction with surrounding matter, so after creation our black hole will effectively enter free fall until evaporation. Unfortunately, this means that the time to fall to a safe distance severely constrains our black hole mass; for instance, for a 20 MT explosion, we would want a roughly 1 kg microscopic black hole, which if I have not miscalculated is expected to [evaporate](https://en.wikipedia.org/wiki/Hawking_radiation) in about $10^{-17}$ seconds. However, again given the size and density of the object, impact with the ground should not change its trajectory or development more than its previous impact with the atmosphere, so I think we can simply increase fall distance to achieve the desired level of destruction. For instance, for a 1000 ton black hole, time to evaporation will be about [84 seconds](https://en.wikipedia.org/wiki/Hawking_radiation), allowing for a fall down to 30 km below the surface. During the fall, the black hole will convert all of its mass into energy, for a total energy release of roughly [20 teratons of TNT](https://en.wikipedia.org/wiki/TNT_equivalent). The vast majority of this energy release will happen at the very end, i.e. far underground, with the total power output being about double the that of the [2004 Indian Ocean Earthquake](https://en.wikipedia.org/wiki/TNT_equivalent) (so quite survivable on a planetary scale, but very destructive for anyone right above the hypocenter). Again, due to the size of the black hole in question, I assume that accretion of surrounding matter is negligible compared to mass loss by Hawking radiation. One should probably also calculate the luminosity at creation. I have treated this as negligible, but have not checked this. Finally, I suppose quantum gravity effects could be important for this kind of thing, so your final mileage may literally vary; but in terms of creating large, scalable explosions from a class of objects that (maybe) occur naturally, it is not a bad fit to your question. [Answer] Okay, so your mages know how to access the five dimensions of space and time. This makes things very interesting because one of the cool things about 5 dimensions is that it can hold more stuff. Think about it this way if you have a desk and you cover every square inch of it with papers your desk can't hold any more papers. But you can go in a third dimension and start stacking papers. Now your desk can hold a lot more papers. In fact, if your desk was square, and we imposed a limit that said that you could stack papers until you had a perfect cube, your desk would hold a lot of paper. Now, then, let's suppose that you have a 4-dimensional sphere move through our 3-dimensional world. What happens? The sphere starts out as a tiny dot, grows to a maximum size, and then it starts to shrink. Just like a sphere passing through a 2-dimensional plane will create a point, then a circle, that gets bigger and bigger, reach a maximum and recede to a point and then to nothing. These two facts give you your answer! Your mages simply have to drop 5-dimensional spheres of iron or rock on these towns. The mage, holds these little pellets of iron. They look like little ball bearings, weigh next to nothing. Give it the old incantation and toss it off the side of the airship. The pellet starts to grow and gain mass, not because ye olde wizard cast a growing spell but because the cross section of the item in our plane of existence is getting larger. It smashes into the town like the wizard dropped an entire mountain on it, but then the object continues to move through the 5th dimensions until it shrinks and eventually disappears leaving nothing but a giant crater where it landed. No exotic materials, no fancy pants explosives, just plain old rocks that happen to be bolders/mountains where most of the stuff/mass is tucked safely away in another dimension that is usually inaccessible to mere humans. Bonus points, because the wizard didn't check the 5 dimensional size, and the 5 dimensional shape of the object, sometimes as the cross section is passing through our 3-dimensional universe the object randomly and violently generates a giant spike or otherwise juts out in a weird way unexpectedly and damages their air ship. This naturally causes the ship to crash killing everyone on board. [Answer] **Nuclear bomb** I know you said no Nuclear bombs, but it seems a bit narrow. Nuclear bombs are complicated, incredibly difficult to produce and require incredibly accurate science. But this is not completely true. A lot of science and accuracy goes into enriching Uranium and maximising the yield. In contrast, you've made a scenario in which it's possible to make more rudimentary but highly effective scalable bombs. Have your mages create a huge cylinder of highly enriched Uranium with a hole in the middle. It's a single naturally occuring element. It'll get close to critical mass. Meaning that if you add a rod of Uranium in the middle it should start fission all on it’s own for a nice boom. Now you only need a way to add the rod automatically after being thrown, but as your mages have airships it seems a small extra step technology wise. "But won't this much Uranium kill my mages as they produce it?" Uranium is chosen for Nuclear weapons as it's relatively *stable* over long periods of time, but with a push they can rapidly undergo fission. It makes sense, as otherwise the power would be leaking out of the weapons at a steady rate. With highly enriched Uranium your mages might've got more chance on cancer in the long run, but there isn't an accute danger. "Won't there be Nuclear devestation afterwards?" Not as much as you might think. The 100% highly enriched Uranium is likely a relatively clean bomb. Most of the radioactive material will only be radioactive in a short duration, expanding their energy. You see people live in the cities already relatively short after the Nuclear bombs fell on Hiroshima and Nagasaki. These bombs are likely more dirty than the ones you'll drop. [Answer] Just use air. Really, *really* highly pressurized air (possibly a pure gas) in a (spherical!) container that is strong enough to contain it, but very brittle, such that a decent impact will cause it to shatter resulting in rapid expansion of the gas inside (i.e. "an explosion"). Your next trick will be figuring out the pressure vessel... Plasma inside a *really* good insulator probably has some good destructive potential, but I'm not sure it would have the necessary *kinetic* force. Since your main criteria seems to be making *a crater*, and not just wanton destruction, that means you need a whole lot of kinetic energy. [Answer] Why not just a meteor? As in the Tunguska impact. It creates an explosion, a sudden release of energy high above the ground, and the vaporized rock disperses. [![enter image description here](https://i.stack.imgur.com/q2QZ6.jpg)](https://i.stack.imgur.com/q2QZ6.jpg) From: <https://www.syfy.com/syfywire/a-half-million-years-ago-antarctica-was-hit-by-a-blowtorch-from-space> [Answer] **A bubble of nothing** Your wizard makes a big bubble inside of which is nothing but a pure vacuum, with water making up the outside of the bubble. You then drop the bubble on the town below. When it pops all that air rushing inwards is going to get very hot, I'm thinking of a scaled up version of [Sonoluminescence](https://en.wikipedia.org/wiki/Sonoluminescence) (which is apparently hot enough to melt steel) so a bubble the size of a building I assume could be hand waved to make quite the bang and thus a large crater. [Answer] You might be out of luck here. I don't think there are any explosives that form naturally. If you really don't want to use gunpowder, you could maybe use ceramics to hold a massive ball of lava, but it would have to come from the immediate surroundings, or it will cool into rock before you reach your target. I'd personally say the aforementioned sphere of gunpowder is your best bet. Gunpowder isn't hard to make; the most basic form only has three ingredients: charcoal, Saltpeter, and sulphur. Sulphur and Saltpeter occur naturally, and Charcoal is easily made with any trees, some dirt, and a fire. There's a technique to making charcoal, but it's still pretty simple. You bundle the wood together with as little air space as possible, cover it in a dirt mound, and set it on fire with a few air holes, blocking them off as soon as you can see fire through them. The idea is to make the wood really hot, but cut off the oxygen supply so it doesn't just burn to ash. For much of history, there was a profession dedicated to this: charcoal makers were called colliers. Your god could simply have given the wizards the recipe. It's worth noting that Gunpowder technically doesn't detonate; it deflagerates. In order to cause an explosion, it will need to be encased in a solid container to build up pressure. To set it off, use a wax-covered rope; cut it at the right length, set the rope on fire, and drop it such that it explodes without giving the villagers time to put out the fire. Ideally, you'd make it explode just before it lands, so that the force of impact won't break the container, but if that's too tricky, you could always build a reinforced "landing gear" on the bomb that's designed to break on impact, absorbing the force and leaving the main bomb with enough strength to build up the pressure needed for a massive explosion. Alternatively, you could drop the bombs with a parachute. You can control how long the bomb takes to explode once lit by cutting the fuse at the right length. you'll just need to keep the prevailing wind conditions in mind. [Answer] I would probably drop some acid or a strong base on them. Turn it all into a pile of goo. I'm not a chemist though, so I don't know how likely that is. If that was possible you'd still have to figure out how to "activate it" from 30m away. I thought about making something shake the ground like an earthquake but I can't see that ever being physically believable. There's just no way to get that much energy out of something that small. Since you got wizards anyways (sorry, I don't know their powers), you could somehow drop a metal sphere and change its volume or mass and just make it 100m for a while and then go back to regular sized. Could it be a lifeform? Like they splice together a certain bundle of plants and then it grows out of control for 100m eating everything and then dies because it can't sustain itself. It could have the added benefit of exhaling a bunch of CO2 and suffocating everything around it. Good luck :) [Answer] There is a suggestion that if metallic hydrogen could be created and exposed in a low-pressure environment (i.e. terrestrial atmospheric pressure or lower), that it would not instantly revert to molecular hydrogen, but might remain stable for a short period of time. If this is correct, dropping a large chunk of metallic hydrogen would likely result in its eventually returning to its molecular state, and then there is the matter of all that hydrogen burning in the oxygen atmosphere. The density of molecular hydrogen at standard temperature and pressure is 0.08988g/l, or 0.00008988g/cm3. The density of metallic hydrogen is estimated to be approximately 1.15g/cm3, so the change from metallic to gaseous hydrogen would involve an increase in volume of nearly 12800 times... and that doesn't include the expansion as a result of an increase in temperature as a result of the hydrogen combusting. There may be a few too many 'ifs' in this suggestion, but it has possibilities... especially if you have magic. [Answer] Nearest thing coming to mind is a tiny particle of anti-matter. It is not "stable" by any means and its arrival is bound to create a substantial havoc, but the other requirements should check. If you cannot remotely create it (make it appear directly at target) then some kind of maglev-in-vacuum container is needed. Any self-respecting God should be able to produce it (actually it's much simpler than obtaining anti-matter). To trigger explosion it would be enough to let air into container. [Answer] # Portals Contained inside the airship are a set of portals roughly 20ft apart, one above the other, magic is used to keep a vacuum between them. Keeping the vacuum and portals going works as a limiting factor. Any sufficiently dense object can then be used to build the necessary kinetic energy. Once sufficient energy is built up, open the bomb bay doors and shut off the bottom portal. Depending on the object used and the speed obtained, the initial slam into the air when the portal magic is ended could destroy the airship. Since extra dimensionality seems to be a part of your world, connecting two points in 3d space may not be so hard, but keeping the vacuum between them may be. Also, creating 'nothing' might be the riddle that kept the secret locked away for so long. [Answer] 1/overdose the whirlwind spell: by chance, arrange the runes/preparations too psyonically perfect and the whirlwind doesnt stop until il has dug a hole and thrown the rocks and ground on top of the neighboring city, the whirlwind mutates into an insane toroidal lissajous spiral and bores downwards flinging rocks and buildings far in the air. 2/portal to an asteroid field, like saturn's rings: The whizard does his teleport spell to saturn's rings, and then teleports back in such a way to send a huge rock through a portal at the city 3/earthquake spell 4/subterranean explosion spell, i.e. put 10 tons of magma and 10 tons of water in the same place underground at the same time, the expansion would be so fast that it would cause a mini super volcano caldera. 5/create a void under the city, so that it literally falls down into a sinkhole and everyone slides into the middle of the city and there are just a few arms and legs sticking out of the rubble. ]
[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/140422/edit). Closed 4 years ago. [Improve this question](/posts/140422/edit) I want to create a scenario where highly technological aliens invade a medieval earth, the kind with magic and dragons and such. But I don't want the aliens to be completely overpowered. I want them to be scary and come out of nowhere but give the humans a chance to win the war. I think the best way to do this is not giving the aliens guns, or explosives, or plasma weapons. These aliens need to have only melee weapons. the aliens would still have far better means of transportation, communication, and armor, but the humans have magic and dragons to counter this. It's a perfectly balanced war. I just need to know if and why such an advanced race would have such primal weapons... [Answer] What if they did bring bucket loads of weapons to try to invade us, but the **environment on earth rendered them incapable of working effectively?**. Maybe the high amount of nitrogen in our atmosphere or even moisture (water vapor). This would be possible if your alien race was a hot headed bunch who did not do their homework first before invading :P. They then have to resort to primitive weaponry like swords and clubs just to defend themselves. [Answer] ### It's a game. > > Welcome to most glorious event of the year! As you all know, each year we pick a planet and select an area of specimen to defeat. This year we've chosen a fun classic planet near Sol, which they've named 'Earth'. > > These creatures are about our height and have a weird pale uniform color. They fight using physical energy. They have long metal sticks called swords. Your challenge this year is to defeat them at their own game! > > > [Answer] What you seem to be describing is some form of 'gap' in their technology tree, assuming the same development path as we have taken. For us, we consider electro-magnetic technology to be almost child's play so as to be so simple, and a massive amount of our modern technology is actually based on this. But, the only reason that we think that is because of the Maxwell equations of 1861-1862. Prior to that, if someone like Queen Victoria had said 'you engineers, build me a box I can speak into that makes my voice come out in front of all my subjects', it simply couldn't be done because we didn't have the scientific *theories* available to design a practical application like radio. We've already made some scientific progress integrating weak nuclear forces with electromagnetism, and we expect the next one will be strong nuclear, then gravity. Once we reach that point, we have a grand unified theory that *could* give us incredible control over the universe and our place in it. But, that's assuming there even *is* a GUT to be discovered. The answer to your question however seems to be in the power sources for your alien ships. If your aliens have mastered theories around Strong Nuclear forces, then they may well be able to initiate fusion reactions, giving them vast amounts of power for spaceships, but not have even basic radio. Also, based on what we know, it's possible that fusion doesn't scale down or miniaturise well, meaning that it's possible (especially if their planet doesn't have the ingredients for gunpowder readily available near the surface) that your aliens could have fast ships, but only basic weapons. Ultimately, what we think of as the 'obvious' technology tree is really a function of what we've discovered through our own scientific endeavours. But, it's entirely possible that other beings, having discovered other principles of the universe first, could get here and then go 'damn! How come they have such powerful weapons and haven't even mastered the basics of space flight?' [Answer] The aliens came here for a peaceful reason. But they had very bad discipline, and some of them decided to invade earth using whatever they had. Swords are too weak for them to be considered a weapon that requires any regulations. [Answer] **They have better equipment, but not with them.** A spaceship is not a place to bring high-powered weaponry. A stray shot can easily damage critical components or puncture the hull. Replacement parts may be months or years away. Consequently, the doctrine is to favour melee weaponry when operating near spacecraft. Your aliens might be able to manufacture some low-grade ranged weaponry given time but there's only so much the Machine-Shop on their ship can actually produce outside of small tools and replacement parts for the ship. [Answer] ## **Magic** If your humans have access to magic, perhaps that could be the answer? The aliens attack a city or village and it is a slaughter as they use guns, bombs, and plasma weapons. Then, at the last moment the towns Elders, a group of wizards or sorcerers, **create a powerful spell to deactivate the weapons** that have slaughtered them. Perhaps they could place a curse on them so that any one who uses those weapons is killed, forcing the aliens to use swords and other lesser weapons. With the weapons deactivated, the attacking aliens are furious but can do nothing as they do not understand the magic and have no control over it. The spell is limited as the wizards were rushed so only affects the weapons, not the transports or ships. It also strongly signifies that **although humanity is weaker, they can still win the war.** This could also affect the plot and story in interesting ways. If the Elders are dead, there is no one left to turn to about using advanced large scale magic (like the curse), increasing the stakes for our heroes. A potential sub-plot could be the last Elder survived and when they are killed, the curse dies with them. The aliens are now frantically hunting them down to lift the spell/curse. [Answer] There is the trope that magical energies cause advanced technology to malfunction. In many universes that combine magic and technology (such as the Dresden Files or the old CRPG Arcanum, and to a lesser extent in Shadowrun), magic and technology do not mesh with each other. In the Dresden Files and Arcanum, simply having a magic user be present near a piece of tech is sufficient for it to start behaving erratically and even break down. Maybe in your world, even the presence of magic on the planet is enough to cause high tech small arms and ground vehicles to malfunction? The spaceships might work because they have heavy metal shielding to protect from interstellar radiation, but as soon as you try to fire your blaster outside the ship, it blows up in your face. [Answer] A fairly simple one but it could just be a matter of culture for the aliens. As a highly honour based society they wouldn't dream of anything less than taking their enemies on in personal combat, seeing ranged weaponry as weak of character and cowardly. [Answer] You mention dragons and magic, so we're talking about a fantasy scenario. Have your aliens initially invade with their standard plasma/laser/whatever guns blasting people to ashes. Then the humans figure out that the lowest-level, easiest defense magic completely blocks that type of weapon. Maybe aliens use lasers and the first level "minor darkness" spell that every wizard learns in the first semester in magic school and that everyone thinks is mostly useful for playing pranks completely eliminates those weapons. Or the $10 protection rings you can buy on every street corner that are so weak that people use them mostly for not hurting themselves so much when they bump into furniture completely blocks plasma. You get the idea. Instead of taking the weapon away from the aliens, make it useless. The aliens suffer some pretty horrific losses before they get the idea that if high-tech doesn't work, then low-tech it is, and go and use human melee weapons. [Answer] ### It's a sport This alien species is very advanced. As a sport or entertaining activity, they invent a new fashion of hunting, similar to the saga of Predator movies. The major difference with the Predator movies is that instead of using all their technology to track down and hunt warriors they make something more exciting: fights at equal levels. A spaceship is sent to the planet, scan down the entire surface and look for an intelligent race. Then, investigate their culture and technological warfare: weapons. After doing that the *sport-aliens* or **hunters are sent to the surface using the same weapons as the intelligent species of the planet use**, in our case swords. The challenger or objective of the activity is to kill the major amount of individuals in the minor amount of time without dying nor using more advanced technology. The alien who kills the most amount of humans is rewarded with honor/trophies/status/money/etc. It's just a game. Even more, it could be televised in real time! [Answer] Can't numbers be a balancing factor? Let's say the spaceship holds a couple thousand fighters, and there are at least millions of humans. That could work well even without magic and dragons. The humans have bows and crossbows, siege weapons (even the romans had catapults and ballistas), so it would be weird if the aliens didn't have any of those (or couldn't copy any of those in a day). [Answer] My initial thought was simply that the ships were not actually theirs (either stolen or borrowed), such that the actual technological level of the invaders was such that swords were the best they had. However you describe them as highly technological so that's out the window. In its place **They aren't engineers, they're technicians** What I mean by this is that whilst someone on their homeworld created their technology, the ones on the ship only know it well enough to maintain and repair. If it was to far damaged from earlier events, or simply didn't function in the environment, they may not be able to work out what was wrong. Imagine an IT support person trying to tank. [Answer] ### Get rid of their spaceships The only way, other than the aliens *choosing* to have an even fight, to make this even remotely plausible would be to have them lose most of their tech - *at the very least all use of their spaceships* - around the time of their landing on earth. Any spaceship capable of interstellar travel, no matter how limited, is a far more potent weapon than anything a medieval society has access to. If they can get, say, ten people to orbit, they can probably just as easily drop a half-ton rock on your capital. Or crush your armies by firing their trusters once or twice. Or do whatever else they like because swords and arrows aren't much of a threat compared to colliding with space rocks at relativistic velocities. Even if you ignore a spaceship's offensive uses, the humans would need pretty much unlimited teleportation magic (which is *also* a weapon potent enough to render swords etc. meaningless), otherwise the aliens' logistical and strategic advantage will make them unbeatable. You can't catch them, you can't siege them, you can't defend your crops, livestock or food stores, or infrastructure. *However*, take that away from them and the tides might turn: ### They probably (used to) rely on their spaceships for almost everything Let's be real, a foot soldier, even with the fanciest of guns, is not going to be much use in a space battle. Why would the aliens waste valuable cargo space on infantry weapons when they have a gigawatt laser turret on their vessel? Why lug around explosives when you can level a city by pointing your thrusters at them? Better pack more fuel or better food or that redundant life support system they recommend for long voyages. The only way you would be worse off is if you ran out of fuel, or broke something critical during the landing, or the engine had some weird interaction with the local atmosphere. But that's never gonna happen, right? Right? Okay, crap, uhm, let's just fire up the fabricator on emergency power to make ourselves some pointy sticks, yes? And pray that the skiff still works, we're gonna need it. [Answer] They came "to serve man". Part of the ethos of getting meat for the dish is that certain weapons must be used. Bloodsport / Rite of passage / Initiation / ... . Various similar - ie the means of hunting the game is part of the thrill of the chase. cf not shooting a sitting duck. Similar is done in a Larry Niven story where large super intelligent (vaguely) dinosaur like creatures live in a high pressure environment. Hunters come to hunt them with well defined allowable weapons. The creatures are bored out of their minds by their environment and welcome their side of the 'hunt to the death' situation. Searches .... [**Bandersnatchi on Jinx**](https://wiki2.org/en/Known_Space) * Jinx, orbiting Sirius A, is a massive moon of a gas giant (simply called Primary), stretched by tidal forces into an egg shape, with surface gravity at the habitable areas near the limits of human extended tolerance. The poles lie in vacuum, the equatorial regions are Venus-like (and inhabited only by the Bandersnatchi); the zones between have atmosphere breathable by humans. Jinx's poles become a major in vacuo manufacturing area. Jinxian humans are short and squat, the strongest bipeds in Known Space. But they tend to die early, from heart and circulatory problems. There is a tourist industry which provides substantial useful interplanetary trade credits for the Bandersnatchi, who allow themselves to be hunted by humans under strict protocols. Bandersnatchi <https://larryniven.fandom.com/wiki/Bandersnatch> <https://wiki2.org/en/Bandersnatch_(Known_Space)> <- good [Answer] The aliens are not willing invaders. They are invading, of course, but only because they have no other choice. They might be the last remnants of their race, with almost all their knowledge, technologies and resources lost, forgotten or spent, and their invasion attempt is their last resort try at survival. Or at least their best bet to secure a few more days, years or centuries until the inevitable demise of their species. Or they might be criminals who were condemned to exile to a hostile planet as a form of punishment or exotic execution. The ship has brought them against their will and without any weapons to defend themselves or tools to return home. All the while the law-abiding aliens back at home sit on their couches and watch that fancy new reality show about a rag-tagged band of shipwrecked guys fighting with improvised weapons against a strange bipedal humanoid race - in glorious 3D transmitted by hovering micro-drones. ]
[Question] [ Most branches of Christianity has always associated witchcraft with the devil, or some form of demon worship. This has been used as an excuse for the persecution of innocent people who were seen as threats to society. (The Salem trials, the Knights templar, etc.). What I want is for the Catholic Church to embrace witchcraft as a legitimate craft in the dark ages, and frame it as a tool for good. However, for whatever reason, only women have the ability to perform it. This is a problem as it can be seen as a challenge by officials to the role of men as leaders. How can the church incorporate the practice of witchcraft into its practices without changing the status quo? [Answer] OK, we need a change in the role of women in Christianity, less opposition to magic, and support for some specific witchcraft practices. Maybe consider starting the alternative history already in Judaism. Until the 6th century BCE, people in Israel and Judah were polytheists and had numerous temples for their main god Yahweh and his wife/consort [Asherah](https://en.wikipedia.org/wiki/Asherah), often associated with a tree (probably as the origin of life) and represented by a 'pole'. At some later point, the temple of Jerusalem must have started enforcing strict monotheism plus the exclusivity of the Jerusalem temple. Earlier writings were censored, and writings from the time are militantly monotheistic. The victory of the monotheistic zealots was so complete that the previous situation only became known through relatively recent archaeological findings. (All of this is *actual* history, not alternative history. Just in case this isn't clear because these facts are so little known.) Suppose the process had not been quite so thorough. Currently there are only a small number of more or less opaque references to Jewish polytheism, such as a few references to Asherah poles, and the first commandment saying that God is jealous and his people are not supposed to worship his competition. *Not* that he is the only one. One can easily devise a variant of (mediaeval) Judaism in which Asherah retained her role to some limited extent, similar to the role of Jesus or that of Maria in Christianity. E.g., Asherah could be seen as simultaneously a human, a second god, and identical with Yahweh. As a consequence of this alternative Jewish theology, Mary's role in Christianity might have become less significant. Or, more interesting for our purposes, she might have been strengthened through a merger with Asherah: Mary as an incarnation of Asherah (i.e. Asherah became flesh as Mary before Yahweh became flesh as Jesus), the consort of Yahweh and the mother of Jesus, therefore simultaneously the mother and wife of God. This weird dual role is not at all unusual for fertility goddesses. This would have considerably strengthened the role of Mary in Christianity. And if Asherah was weak enough in our alternative Judaism, then it was Mary who dominated the duality of Asherah-Mary. In the time before the establishment of the Christian biblical canon, there were plenty of religious writings floating around that are now lost completely or were only recovered in fragments. If they mentioned Jesus at all, they were usually known as gospels. One of these was the [Gospel of Judas](https://en.wikipedia.org/wiki/Gospel_of_Judas). It is worth reading the Wikipedia article to get an idea of how radically different non-canonical gospels could be. There is also a text known as [Gospel of Mary](https://en.wikipedia.org/wiki/Gospel_of_Mary). As it is not well known and survived only in part, it is probably a good idea to rewrite it as follows: Mary the mother of Jesus = Asherah = Mary Magdalene! As in many apocryphal writings, Mary is the closest disciple of Jesus. In addition, she is also his wife! (This is logical because Jesus and Mary are incarnations of Yahweh and Asherah. As they are not normal humans, incest is not a problem. And maybe contemporaries didn't suspect anything because Mary didn't age since giving birth to Jesus?) Like Jesus, Mary does the occasional miracle. However, she does them in less spectacular ways, e.g. healing people by means of holy plants. Presumably she already had some practice when Jesus was born, and taught him the trade. The Gospel of Mary should also contain an explicit statement saying that Jesus was the only man allowed to engage in witchcraft. Otherwise it's strictly for women. This should also explain any anti-witchcraft passages in the Bible that you might otherwise have a problem with: they only apply to men! However, alternative Christianity isn't actually a feminist religion. Misogynism creeps in in various ways, e.g. in a partial equation between Asherah/Mary and Eve. To stress this, the snake is added to the Asherah Poles, resulting in the [Pole of Asclepius](https://en.wikipedia.org/wiki/Rod_of_Asclepius). So we have the connotations of fertility, original sin and healing all in one symbol. Just like 6th century BCE Jewish temples, Christian churches have two altars: A main altar with a cross in the middle and a side altar with an Asherah pole in the aisle. This isn't so different from reality, where some old Catholic churches actually have side altars with depictions of Mary! [Answer] Actually, Catholic doctrine didn't include belief in witchcraft most of the time. To believe that simple village women would make deal with the devil and gain thereby magic powers was a heresy of itself. > > The Germanic Council of Paderborn in 785 explicitly outlawed the very belief in witches... (from [Wikipedia](https://en.m.wikipedia.org/wiki/Christian_views_on_magic?wprov=sfla1)) > > > Even the 'Hammer of Witches', although written by Catholic monks, didn't find much popularity among Catholics, and was more popular among Protestants. It wouldn't, however, make witchcraft any more palatable for the Church on itself. I think, the easiest way to make medieval clergy tolerate magic of any kind would be to treat it as science, as a result of manipulating natural laws in any way, rather then as any mystical process. Another possible variant, although more problematic in my opinion, would be to treat magic as a result of prayer, a miracle. If your witches would use the trappings of Christianity, pray to the God and St. Mary, use crucifix as a ritual tool, possibly, maybe, it could be seen as a miracle granted by the God. That the women were able to do that, and not men, could be seen as a special intervention of St. Mary for the other womenfolk. The second version seems to be a bit more problematic to me, though. Magic as science would be no different from medicine, while magic as prayer would be in conflict with Church hierarchy. It would mean more conflicts and power plays inside the structure of the Church. Special monastic orders of magic-women, maybe, the attempt to keep them from high positions in the Church by men. It would be complicated. [Answer] How exactly are you defining witchcraft? It’s a tricky one, but aligning witchcraft with midwifery might get you somewhere with “only women have the ability to perform it”. I’ll have to come back to edit this, but I think Diane Purkiss has done some good work looking at the overlap between late medieval midwifery and witchcraft - if the Church sanctioned midwifery, encouraged the use of birth girdles and other ‘superstitious’ items, and allowed charms and amulets (have a look at Don Skemer’s book on Textual Amulets), then the two might have gone together without the negative connotations that actually ended up happening. The other things worth looking at are accounts of mystical happenings. Again, I’ll come back and edit this when I’ve got all my notes, but there are examples of things like mystical pregnancies (generally women swelling with the Holy Ghost), devotional anorexia/inedia (surviving solely on the Eucharist), and other things that generally happened to women. Caroline Walker Bynum’s *Holy Feast And Holy Fast* is a great place to start if you’re interested in that kind of thing. If you start with the kinds of things that *were* sanctioned (or even venerated) by the Catholic Church in the period you’re interested in, especially things that happened to women specifically, then use that as a basis from which to build your witchcraft practices. Female healers? They could be church sanctioned midwives. Able to perform miraculous acts? Incorporate them into hagiographical tradition. :) [Answer] How to incorporate magic? Very easily. Slap a Saints name on it. <https://www.catholic.org/saints/stindex.php> <https://en.wikipedia.org/wiki/List_of_saints> If there's not a saint for what you want, call it a Jesus something or another. How to integrate woman controlled powers? A few different ways, but totally still doable. Chain them to a controller that's male. It would require a cradle to grave scheme, trained from birth. Sequester them to nunnery. How do humans control other humans? Lots of ways. Women have always had a place in the Catholic church. Any religion involves some magic. [Answer] I'm going to approach this from a different direction. Rather than looking at our world as it is & making parallels, I'm going to cheat completely & use someone else's parallels... [Terry Pratchett](https://en.wikipedia.org/wiki/Terry_Pratchett) wrote a lot about religion & [witchcraft](https://en.wikipedia.org/wiki/Discworld#Witches). In his world, the gods all actually existed - you didn't have to believe in them if you didn't want, but you knew for sure that they were actually there. I don't recall him ever having a 'devil' parallel at all. [1] His witches, therefore, rather than being the stereotypical 'devil worshippers dancing naked round standing stones' [2] took an altogether different view. The magic they did was sometimes 'real' but more often than not they relied on solid midwifery skills, a good knowledge of herbs & a very good grasp of "headology" [that's psychology to you & me]. He therefore mainly avoided the potential clashing of dogmas by not making them compulsory in most cases & more specifically by never tainting his witches with 'evil'. [3] A witch with this cultural background could more easily be seen alongside a more real-Earth religious system, as is doesn't really clash with it. Priests generally don't have issues with midwives, pharmacists, or psychologists, only with 'devil-worshippers' - so if your witches have never been seen this way there's no need for them to ever be at odds with organised religion. They could even, at a push, be 'nuns with special jobs'. --- [1] *[after comments]* He did in fact have one devil character, but somewhat out-of-canon, so I'll leave him out for this comparison. [2] He did use parallels to Shakespeare's witches, "When shall we three meet again?" etc, but it was often followed by discussion over who couldn't make it because their Doreen couldn't babysit that night, or arguments over who would bring the cakes & make the tea. [3] He did parallel the 'witch gone bad' using references to the ones who lose their way & turn towards a 'dark side' would end up living on their own in out-of-the-way gingerbread cottages & be burned in their own ovens by small children. These witches were seen even by their fellows [*'sistren'* (sic)] as aberrations, & don't form a part of the overall world view of witches. [Answer] Step one: find some heathens and learn their culture. Step two: take not of whatever parallels you can find between their heathen culture and your own. For example, if they believe in a master god, you can trace a parallel to your own single god. Step three: copy their traditions, but replace all the symbolism with sigils and images from your own tradition. Step four: repeat all steps above, ad infinitum. --- For example, the Bible says that Jesus was born around the time of a heathen census, and those did not happen in December. But some heathens that the church really wanted to convert only celebrated their major god birth on the solstice of winter, so the church preached to them that it was JC's b-day that was actually being celebrated that time of the year. It stuck, and to this day we celebrate the day when the three wise men (or twelve, depending on tradition) dressed in red and broke into the stable where Mary gave birth through a chimney to put some incense, gold and... stuff into his socks. --- There was also something about a mesopothamian goddess of fertility that was celebrated some moons after the other heathens orgies. But you know how these kinds of things always get lost through the ages and translation, so now we celebrate the rebirth of god by evoking a bunny which lays colored eggs (in some countries, those eggs are also made of chocolate). --- Sometimes you get a twist when you try to reform your own religion. One person's celebration of the time when their people escaped slavery by running away from it is someone else's celebration of someone being flogged and hanged on a cross in a very passionate manner. --- Last but not least, about only women being able to do it: if you are running a machist, mysoginistic organization in a world where women can evoke fireballs and hurl them at you, it is in your interest that they are no longer able to cast magic and that all the knowledge on such things is controlled by the patriarchy. Because the moment they learn to cast again, the evil system goes down. This is actually why the priests are forbidden from marrying and stuff. [Answer] ## Only some types of magic are forbidden Might not be as difficult as you think, depending on how you set up your world's magic system. The Bible (OT) lists a number of specific kinds of magic practices that are explicitly forbidden - those listed in Deuteronomy 18-10, and one in Exodus 22-17. Since it separately lists the types of forbidden magic instead of just a general prohibition against all supernatural practices, this suggests that any magic that does not fall under these particular categories are not forbidden. Indeed the Talmud lists various anecdotes of people using supernatural abilities - and makes a distinction between "miracles" (which are unique events) and those which are done through specific knowledge of the world's inner workings. Medieval Kabbalists were quite all right with making various forms of protective amulets and other practices that they did not consider to fall under the categories of forbidden magic. Now here's the problem (and the fun part): the details of what these specific magic types *are* are not well documented. There's also a fair bit of discussion as to whether they refer to magic at all or were simply particular idolatrous practices that were well-known at the time and subsequently forgotten. Some specific practices that are generally agreed upon as forbidden include divination through the dead (necromancy), divination through a particular animal's bone placed under the tongue, anything that involves the worship of a false deity, or practices that "harm the world" - though this last one could be more of a statement about how the magic is used. The Talmud mentions that summoning small animals is generally forbidden, but is permitted in order to fight off a threat. Also, King Saul inquired of a necromancer at one point despite it being explicitly forbidden, so there's apparently some room for flexibility in times of need. Anyway, TL:DR - some types of magic are permitted, other types are forbidden. The Bible only forbids the forbidden types, and even the forbidden magic may be acceptable under extreme circumstances. [Answer] The problem is that the dogma is kinda... dogmatic! As a result, everything this is not commonly observable and does not exists in the Bible or Evangiles is at least suspect. Witches are not common in our world and remember that Galilee had to refute his theorie of the earth turning around the sun not to be burned as heretic. But nowadays, science has established that the earth is nothing more than a planet turning around its star (which is called sun) and it is no longer a problem. In a world where magic would be common, using it *decently* (according what Catholic hierachy thinks) would not be a problem. Another example is weapon factory or usage. Bible does says *Thou shalt not kill* but soldiers and weapon smith are not condamned. But in the middle age, crossbow was banned by Catholic church because it could be used to too easily to kill knights, until regular armys use it commonly. Another example is medecine. Catholic churched condemned dissection of corpses, until it became a common practice. So if magic was rather common in a world, the Catholic church would have adapted to it. [Answer] There is some debate on the Old Testament translations from Hebrew into Latin and English around the topic of [witches and wizards](http://www.newadvent.org/cathen/15674a.htm). The term poisoner is thought to be more accurate than the Witch or Wizard. Some people, in modern times, have used that fact as fodder for the arguments that the prohibitions on witchcraft were actually male chauvinism seeking to control the practice of midwifery. But, in the context of when the Hebrew Bible was written, [it is thought to have meant people that use witchcraft to harm another.](https://quod.lib.umich.edu/e/eebo/A62395.0001.001/1:7.6?rgn=div2;view=fulltext) If this idea is acceptable, then your story's Catholic World might accept witchcraft if it was used for good purposes and not selfish purposes or injuring another person. There are still many prohibitions in the Bible against interacting with familiar spirits and demons, so the rest would be how does witchcraft work in your world. [Answer] Make Mary rather more than just the vessel who delivered Jesus into our world. Make her instead the greatest of the white witches. Of course, the early church was misogynistic, and so this would be an extreme rift from out own world. Even so, stranger things have happened. Had the Plague of Justinian been defeated thanks to the efforts of some herbalists/witches who found out how it was transmitted (fleas) and managed to stop it (maybe an obscure African plant we know as Pyrethrum) ... in our lifetimes we had a very close shave with SARS, which was defeated by reducing its opportunities to infect new victims. Add as much magic as you need. [Answer] We already have an example of Catholic-incorporated witchcraft that survives to the modern era: exorcists. The use of magic to combat magic is a time-honored tradition, pitting the power of your god against whatever the other person worships. It's like religious Pokemon, except Mew2 commits genocide to prove a point. While today's exorcism has slowly adapted in reaction to increased understanding of mental illness, there are still rare instances where the Church decides that this is not an insane person and if the family agrees, an exorcist can be utilized in an attempt to drive out the foreign spirit. What do we derive from this? 1. That magic is okay to the Church if it comes from God, and not from you. 2. That it is used towards the glorification of God, not you. 3. That it solves a problem that would be very difficult to address any other way. [Answer] One major advantage that the church had as it persecuted the magic wielding witches was the fact that there wasn't any magic wielding. At least, none that was powerful enough to put a stop to the persecution. Makes the inquisitors' job nice and cushy, don't it? Now, **if witchcraft was real and/or much more powerful**, you'd have serious battles on your hands, where witches would sometimes kick the inquisitors' cushy behinds. In a world of power witches, many people and society in general would have use for witchcraft skills and you might add to your story social structures like guilds and schools of witchcraft, or positions in other institutions (e.g. royal court witch), that would lend **some political power to witches**. Under these circumstances the church would have a hard time labelling magic as "evil" and abuse magic users. It would be much more practical and profitable to have a truce at first, then make use of witches, then label useful magic as a holy gift from God. You could have magic-nun-healers dispensing god's grace and healing to anyone willing to pay/pray. Bear in mind that it's the **practical use** of getting people to be faithful or give money to the church that is the key. A healer who won't serve in the name of the church or can't fight the church, is of no use and is therefore not holy. We can happily murder her. Now you can go ahead and label the "other" magic users as evil (necromancy/destruction magic etc, but generally anyone who won't work with the church) and have a magic war where the church becomes the greatest supporter of witches due to a common enemy. [Answer] ## Here are a Few Turning Points That I Think Would Make a Difference **Simon Magus and Peter (approx 63 AD)** Simon Magus was a Samarian (Northern Israel) magician who, around 63 AD converted publicly to Christianity and was baptized. He was criticized by Peter for trying to monetize his own conversion. The addition of a mere few words to the account recorded by Luke in Acts, (8:20) "...it's not your sorcery, but because you thought you could buy the gift of God with money..." would have help give clarity to church fathers when thinking about the subject. **The Murder of Hypatia (415 AD)** Hypatia was a popular Egyptian professor and a dedicated atheist (neoplatonist). Because of her popularity, church leaders approached her socially and for advice. Because of this, Hypatia became deeply involved in a internal political struggle within the church between her friend and recent convert Orestes (who was also the Roman prefect, or governor of Egypt) and the "rightful" heir (people believed church leadership might be hereditary) Cyril. The entanglement got Hypatia murdered by a mob. Later historians would record her both as a witch and a saint. If, instead, you had something like the [O'Reily-Stwart Debates](https://www.youtube.com/watch?v=oyJ9j-OowqY) between Hypatia and someone, recorded by antiquarians. Both sides could walk away claiming victory. It might have made clearer for posterity contemporary atheist values (and distinguish them from "magic"), better define what witches or magic was, and maybe have saved Hypatia's life by convincing one of the two sides to back down. **King Phillip of France and the Betrayal of the Knights Templar (Friday October the 13th, 1307 AD)** What do you do when you owe a stupendous amount of money to the only international bank in the world, and you need a loan? Why, of course, you arrest the bankers, seize the bank, and approve your own loan request! King Phillip set the precedent for the convenient finding of "witches"; government searches as a cover story for property confiscation. The way in which this was done would be mirrored so closely by the Spanish Inquisition (1478) that we tend to think of these two events as simultaneous. The Pope (the seat of the church was in France at the time) was a puppet of the French king, so it might have been too much to hope the Pope had took a public stand on defaming, torturing, and murdering the church bank. Edward II had just become king, and was too weak to take a stand -- but maybe he could have. Maybe if cynical historians had done a more thorough job of popularizing the money grab for what it was, instead of allowing the charges of witchcraft to linger, nor set the precedent for Spain that this way of doing business got results. **The Spanish Inquisition (1478)** Ferdinand and Isabella (the same pair of Columbus fame) were a pair of weak monarchs over an extremely divided Spain (7 kingdoms, 5 languages, and half-occupied by the Almohad Caliphate (empire) in the south). You know how we can unify all these people under our rule? We'll search out non-conformers and take their stuff! Worked for King Phillip, right? The Spanish Inquisition set our popular attitudes about magic and witches, despite it being largely a political land and property grab by too weak monarchs. Again, bitter (and preserved) critique by historians would have helped keep attitudes in the present more level. Little known fact : Pope Sixtus tried to reign in the Inquisition from within. Maybe he could have publicly denounced them, instead. Or, maybe if the Pope had been really clever and suggested burning (instead of seizing) the belongings of witches, would have nipped the profiteering motive from Ferdinand and Isabella. Maybe Reformist attitudes could have matured early and denounced the action (Martin Luther would nail his theses to the wall in 49 years), with the protection of the German nation behind them. **Salem Witch Trials (1692 AD)** By now steeped in a lot of paid-for press making witches bad. It's possible these would have happened anyway -- there's thought that something medical that drove the people temporarily insane. Maybe without the imaginative groundwork laid by the Spanish and French Inquisitions this insanity would have manifested as dragons in the New World? Maybe fairies? Would have resulted in, perhaps, a new myth, instead of the shameful memory. [Answer] Just give "witchcraft" a different name. It is how authorities incorporate stuff that outwardly doesn't complies with their heavy-hand-enforced morals. Just like how "Socialism with Chinese characteristic" is more akin to state-controlled capitalism and not socialism. In the anime "A certain Magical Index", the Christian church, as well as other religious sects, deploy magical fighting forces to further its goals. They call their witchcraft "holy spells" and such. [Answer] Practically though, you would want to confine all witches into specialized monasteries and/or a distinct Christian order like Dominicanes or Jesuits. Catholic church already has a huge predisposition towards displaying infernal beasts, skeletons, skulls and all such attributes of witchcraft in their own churches, which is not shared by other branches of Christianity, so in some sense it would be easier for them to integrate witches dogmatically. [Answer] Each idea, requires either adding soem flexibility on church's ideas, or stretching the definition, usage and limits of witchcraft. Maybe both. Idea 1: "We live in darkness to serve the light." Okay, very basically, witchcraft in medievel fantasy settigns can do some nasty stuff, depends on definition. But being usually associated with demonic powers, witchcraft is known to inflict misery. But, power is power. There was a historical example I vaguely remember about a pope, claiming he had literal demons chained under the church's basement. Think of something like that. An enslaved demon, and church is using that demon's powers with the help of many women who can channel that power. "They reminds us what the dark powers can do, they offer us a way to undertand and build counter-measures against it, and they offer us a wide arsenal of powers in our command. A... Necessary evil." Idea 2: "Our curse is our blessing." Maybe witchcraft is originated from a curse. Or takes a heavy toll. So, only a special group of women, who can handle the side effects, and specially trained, indoctrinated, are serving to the church as assistance in areas where non-magical methods won't work. But all actions of these women needs to be regulated. That is why "wild" or "rogue" witches, who perform witchcraft outside church's interference, are known as heretics and dangers. So they are executed on the spot. Some other women can also wield and learn witchcraft, but it is not systematic. Idea 3: "Monster on leash" Inquisitors aided with trained, perhaps tortured witches. Maybe they were broken by other means. Up to you. Church takes and raises whoever they can control, and kills those who they can't control. All for the sake of power, all because of the arrogance of the bishops and pope himself. Idea 4: "These nuns are too good of a fighter/healer/scholar for a human!" Witchcraft, is not exactly openly performed, but rather, a group of nuns who wields weapons and trained in martial arts or trained in healing etc are actually performing witchraft to further boost their abilities. But, they are a seperate organization under the church who plan on their idea of devotion by whatever means necessary. So, for others, they are just "Nuns who are exceptionally trained." And they become a nun to hide their methods under the church's protection. Idea 5: "Weapons of my enemies." Maybe women can "activate" artifacts made by witches, and they can use these "artifacts to full potential because females in this setting has a naturally higher magical or witchcraft talent. And it shows. So, these women can "use" witchcraft based tools and methods, but are not witches themselves. All these artifacts were actually creation of witches church took. And someone figured out that women can use these artifact. Creating a defence force who can actually benefit from the "weapons of church's enemies." Idea 6: Desperation Maybe the famine, plague, wars and many other disasters you could add, caused the church and people following them to be desperate. So, they captured young witche trained them, and added them to their ranks. It was not something church planned, or even wanted. But, desperate times brings desperate measures. Idea 7: Puppet or battery Maybe the "burnt" witches are not actually burned, but taken to a special place, placed under a... surgery... that deprived their senses, and allowed someone to wield them as staffs or sources of magic. Maybe these witches were turned into small containers that grants power of witchcraft to whoever female, touches it. Maybe church is using these "witches" as battery for magic and training lots of women just to use all the witches they captured and... turned. Check out the catridge of the bondrewd from made in abyss. Similar method. ]
[Question] [ In my worldbuilding, we're looking at the typical dystopian setup of most of humanity being in some way dead and gone. I'm not looking for what would happen if the internet shut down in general—that seems to have been answered more than enough. But what happens to the data on the internet? If, say, people managed to band together and find a way to restore internet access for the remnants of humanity (assuming power/equipment), would all of the information currently stored on the internet be gone due to the systems having been shut down? Would it ever be possible to recover any of the old information from the internet, assuming you could access the internet (as a whole or in part) again? [Answer] The "Internet" refers mainly to the network connection that makes millions of computers accessible from any connected device. The actual data, however, is stored on millions of mass storage devices, ranging from small platter or SSD volumes to optical or magneto-optical carousels containing petabytes in a single location. None of that data would be significantly compromised by loss of the network backbones; all that would be required to make it accessible again is to restore high-rate data connections between a substantial fraction of the machines that mount and read/write those storage volumes. [Answer] Don't forget you'll need to deal with passwords. Even the if you power on a server and all the bytes in the disks survived you'll need to deal with decrypting any encyrpted data or having login passwords. It's not as if you'll be able to a password reset as no one's email will be working. [Answer] **"There is no cloud, there are only other people's computers"** As pointed out by [Zeiss Ikon](https://worldbuilding.stackexchange.com/questions/220413/would-it-ever-be-possible-to-restore-the-data-currently-on-the-internet-if-the-i/220414#220414), data isn't on "the internet," it is on computers. But I expect significant problems, up to and including data loss, when communications go down and later get restored. Programmers are making mistakes all the time, not thinking of possible errors, and so programs are buggy. The recent [Log4Shell](https://en.wikipedia.org/wiki/Log4Shell) exploit is a good example where a possibly beneficial function could be abused in unexpected ways. * I would expect that a number of [caches](https://en.wikipedia.org/wiki/Cache_(computing)) have to be rebuilt, with a loss of some recent data. * Badly made systems could be impossible to restart, with component A relying on component B, component B relying on component C, and the most recent version of component C relying on component A (even if the original C didb't). [Answer] It depends on how long does it pass between the shutdown and the restart: the data that we see in the cloud is stored in some data centers around the globe, and these data centers, if not physically destroyed, will keep the stored data as long as the memory allows. Solid state memory stores data under the form of localized charges, and when the amount of this charge is changed, the data is corrupted. This can happen either because of electrostatic discharge (which also physically damages the components) or by charges present in the environment, typically supplied by cosmic rays and radioactive decay. The more the data storage is exposed to these sources, the higher the chances of data corruption. [Answer] **Data loss will be unavoidable** If internet is abandoned for a relevant amount of time, with no way to guard loss of information, because there has been no access and no maintenance personnel, you'll have issues. Things will be lost forever. This is already what happens now.. information not accessed will get lost. Without active internet, your DNS servers will get no requests. At some point, DNS servers will also cease to communicate URLs between them, to keep up the DNS database. When too many DNS servers get lost, the backbone of the information (URL's and links) will disappear. As L.Dutch made clear, it would depend on the amount of time past, what would happen with SSD like storage. Any information on magnetic media will get wiped out in 30-50 years, whether machines are switched off or not. A spinning harddisk wears out even faster. Normally, long before a harddisk has issues, the datacenter will move data, replace it, and move data back.. as long as there is personnel. In your scenario, data will really get lost. I can add the importance of the *close down scenario*.. how did the internet shut off ? how well were files preserved during that event ? [Answer] The data is stored on devices that, 99.9% of the time, withstand a power failure, and work just fine once power is restored. However, leaving such devices alone for a long time can make them unreadable. I have tried to access a hard drive I had stored on a shelf for two years, I was just going to see if I could use it for something else. Despite being undisturbed for those years, it was no good anymore, the only thing I could use for was a paperweight or doorstop. There is also the problem of the network itself. It takes software to access web pages, unless you are going to engage in a lot of searching for javascripts and templates and other stuff, the raw data of web pages is not easy to figure out. An internet page may read both code and data from remote devices; when you read Amazon, it is building the page code it sends you on the fly from dozen of sources. If any of these sources are missing the page may not render at all. This interdependency across the network can mean the whole Internet degrades rather quickly, because many elements can be affected by each hardware failure as time goes on. If it goes down for a few weeks, I'm sure it will come back fine. If it goes down for a decade, I doubt it would come back fine. [Answer] The biggest concern IMO is whether the Domain Name System (DNS) remains functional. DNS is responsible for converting names (e.g. `worldbuilding.stackexchange.com`) to addresses (e.g. `151.101.193.69`). I see a few potential problems here: 1. DNS is hierarchical so if the top-level servers (e.g. those for `com.`) are unreachable or down then no addresses can be looked up. 2. The DNS servers for each domain (and subdomain) are maintained by the site owners. If the server addresses change when the Internet is brought back up and the owners aren't there to update the DNS records then the sites at those domains will be unreachable even if the servers are up. 3. As pointed out by @Goodies in the comments, domain registrations expire and when they do the registrars1 typically deregister them (or take ownership themselves). Even if automatic deregistration doesn't happen, domain names can only be registered for 10 years at a time2 after which the domain must be re-registed with the TLD's registry operator3. If this doesn't happen then the domain will likewise be deregistered4. In this case I'd expect only government domains (at or above the state/province level) to continue to be resolvable over the long term with most domains (`*.org.`, `*.co.uk.`, etc.) becoming unresolvable. 4. Related: The Internet is not a single place but rather many places (servers) all over the world. It's not enough to just restore access to your ISP, you also need to restore (at least some of) your ISP's links to other providers, those providers' peering links, etc. --- 1 Registrars (such as GoDaddy or TuCows for `com.`) sell domain names at retail/wholesale. 2 At least for some Top Level Domains (TLDs), possibly for all. 3 I'm not sure whether this is true for all registry operators.   A registry operator runs the actual domain name servers for a TLD (e.g. VeriSign for `com.`). Registrars notify the operator when changes are made to individual domains' `NS` (nameserver) records. 4 Again, I'm not positive that this is the case for all registry operators. [Answer] Probably not all of it. Some systems are "trivial". Think of your traditional servers and networking hardware. Just power on all the equipment and they have running configuration saved and automatically restart needed things. Make sure that interconnections are also powered on that is every piece of equipment on the way between them. This is however forgetting durability and other such concerns. On other hand specially with cloud and very large systems this is unlikely to be enough. I think getting up your cloud platform is rather involved process from cold-start requiring very specialised and probably even undocumented knowledge. Needing things done in just right order with probably some caressing and giving time to get certain programs running and stable before starting next ones. And at that point you might not be even running the stuff we think of as Internet there. Those thousands or hundreds of thousand individual web sites, servers and others might need similar actions to get up and running. Or in worst case they might not even be recoverable. Our modern software development some times isn't exactly stable or great. And likely mean that you need some other system up and running or even some random laptop somewhere from where you run other software to upload the software and run it in cloud. All the steps above might be needed to access some of the data. Or they might not even be enough. [Answer] In addition to the catastrophic DNS problems Alex Hajnal mentions there is a related problem with certificates. Within a few years everybody's certificate is expired, nothing that uses https works. In theory this might be averted by setting the clocks wrong--but the people restoring it likely wouldn't know this and very well might not even know what time to set it to. And even if they get it back up, those certificates will be ticking time bombs--the people with the passwords to update them are gone. ]
[Question] [ Suppose I have a very big area as big as Gobi desert and it is windy all years round, but it is covered in snow instead of sand since Earth is experiencing another ice age right now. I am not sure if dunes would still forms regardless of the type of particles or it must be sand and only certain sand? [Answer] Snow dunes already form on Earth, like one can see in all regions where snow and wind are plenty. [![enter image description here](https://i.stack.imgur.com/XnyQu.jpg)](https://i.stack.imgur.com/XnyQu.jpg) However they do not reach the sheer dimension of sand dunes because of the difference in the interaction between the constituting particles. While sand grain keep staying separate and individual under the conditions present in a sand dune (to start coalescence they need to be at pressures and temperature way higher then those present on the surface), snow flakes can very quickly and easily coalesce and form larger bodies of something which will end up being a block of ice. What you end up having is then not a dune but an ice sheet/bulge. To have dunes you need to have particles which do not coalesce together. [Answer] I've lived (and currently live) in areas where blowing snow is common. Of course dunes form, though we call them drifts, and they can form thicknesses of a dozen feet where other surfaces have but inches. From a practical perspective, there's little difference between solid water and solid silica beyond density. But understanding how dunes form is important. High enough winds will flatten everything. Low enough winds won't form dunes. The right winds form washboards (dunes). But it's also important what the limitations of ice crystals are. Photons are hot! Even in the coldest regions of Earth, sunlight will melt surface ice. This means you must have a low enough level of solar energy that the surfaces of the dunes aren't subjected to a daily thaw-freeze cycle. Of course, as I think about it, that thaw-freeze cycle might be a wonderful suspension-of-disbelief reason why snow dunes form in a way that looks exactly like desert dunes. Should sunlight thaw the lighter density snow during the low-wind day, the high-wind night can refreeze it and pile it up, causing a natural form of windbreak, which would be the core of dunes. The leeward side of the dune would always be icy compared to the fluffy windward side. This would also cause a really cool story element. [Answer] Have snow *on* the sand dunes! [![image of sand dunes covered in snow](https://i.stack.imgur.com/bPKNF.jpg)](https://i.stack.imgur.com/bPKNF.jpg) Just need an area meeting the conditions for a desert, and have it close enough to a region where snow can occurr. Regular weather patterns move snow into the desert, and viola, snowy dunes. [: As for dunes made exclusively of snow, it's not to my understanding that snow works like that. Whereas sandy deserts are blown by the wind over time to form dunes, snow is constantly replenished. It sticks to things like trees and stones, while sand kind of sits on things. Very different properties! Can't make a snowman out of sand yk? [Answer] Yes, snow dune-like structures called [sastrugi](https://en.wikipedia.org/wiki/Sastrugi) are a thing. > > Sastrugi are distinguished by upwind-facing points, resembling anvils, which move downwind as the surface erodes. These points usually lie along ridges perpendicular to the prevailing wind; they are steep on the windward side and sloping to the leeward side. > > > [Answer] "Not really", is the answer to that. The problem is that unlike sand, ice crystals can sinter together to form a larger solid blob, they can melt (with the water generally being absorbed into the surrounding snow) and they can also sublime (turning directly into water vapor... something that can happen with very find windblown particles). Snow flakes rapidly break up into smaller ice crystals when windblown, unlike sand grains that take much longer to wear down. You can get some transitional forms that seem a bit like dunes in the form of snowdrifts, but these are temporary things and continued wind can transform them into much harder, pointer and more angular structures (the sastrugi mentioned by Monty Wild) in contrast to the generally softer and more rounded structure that sand forms as sand grains can't sinter together or sublime away under normal circumstances. Wind-hammered snow can have almost rock-like hardness, and without a supply of fresh snow surface ice will be scoured away by the wind and sublime into the air causing features to reduce over time. Combinations of wind and sun and dry air can cause some visually striking things such as penitentes: [![Penitentes ice formations at the southern end of the Chajnantor plain in Chile](https://i.stack.imgur.com/cFn0H.png)](https://i.stack.imgur.com/cFn0H.png) These spikes of snow form in very dry, cold mountainous areas and can reach several metres tall. ([image credit ESO](https://en.wikipedia.org/wiki/File:Penitentes_Ice_Formations.png)) > > Suppose I have a very big area as big as Gobi desert and it is windy all years round, but it is covered in snow instead of sand > > > What you're more likely to have is something like an [ice sheet](https://en.wikipedia.org/wiki/Ice_sheet) where any interesting shapes are going to be driven by glacier flow more than by wind effects. Glaciated terrain can certainly be interesting and varied, but it only superficially resembles a sandy desert. Also have a think about where the moisture is coming from to drive your snowfall, and what is triggering the precipitation... if you want heavy snowfall over long timescales, you're probably going to want some mountains, rather than a big plain. ]
[Question] [ Now, my world is old. ***Very*** old. And, unfortunately, the story locked me in a paradox. Namely, the colonization of the [lush caves](https://worldbuilding.stackexchange.com/questions/199687/what-would-be-the-evolutionary-drives-of-a-lush-cave-environment) featured in another of my questions, which also have a name now (Harat Caverns). You see, a small group of intelligent dragons colonized this place 3.5 million years ago. They were in the renaissance age. **How can I prevent them from progressing beyond the early industrial point**? And, as a side note, **why would they prefer medieval weaponry and customs**? Do note that magic does exist. Edit: Welp, apparently due to bad writing on my part, everyone thinks I'm just talking about the dragon civilization. I'm talking about the entire *world*. Also, if it helps, the setting is a large archipelago in a mostly temperate zone. I also still want the use of fossil fuels. And there are humans, as well as 8 other races. And the dragons. Sorry about the misunderstanding. Have upvotes as a compensation. Edit 2: I had an idea. I decided to come up with a special deific monster called a Watcher, or *numina*. While they've been around for a while, I only just realized how I can apply them to this. You see, *numina* used to only stalk roads at night, killing travelers, but I realized that perhaps they can prohibit other things as well. Do with this as you will. Edit 3: New developments! Now, iron is extremely rare, only found in trace amounts in copper ore, and tin is almost nonexistent. Meanwhile, zinc is a bit more common. As a result, brass is used for almost all the things bronze, iron, and steel would be used for. While this may have unforeseen consequences, I do wonder if it would help. Also, I have accepted numina warping, and have decided platinum is immune to it. Also, in response to RobbieGoodwin, who had asked several good questions, what I mean by Numina being "deific" is that they are godlike, but not exactly gods. They are unkillable, but their powers are quite limited, only allowing for a limited, chaotic control over their environment. The temperate archipelago thing was included because I felt that while I may not see any connections, someone else will. Same with other races. And finally for fossil fuels, coal and oil exist, but natural gas does not. And, another thing: this world is completely unaware of air pollution, so that would not be a viable answer. BTW, here's a [link](https://chat.stackexchange.com/rooms/121156/the-new-world-project) to my chatroom if you're interested in the world. [Answer] I am surprized nobody mentioned lack of materials. Lack of coal or metals would prevent most machinery from being made. In addition, use of any fossil fuel in a closed environment of a cave will quickly deplete oxygent. Maybe somebody tried it early on, and since then, fires are no longer allowed. Dragon's fire breath is not a fossil fuel, it uses methane that dragon produces from their food, so basically similar to exhaled CO2 or burps or farts. Unfortunately, dragon's breath is not hot enough to engage in any advanced metallurgy. [Answer] **These dragons are the original ones who colonized the cave.** Yes: they are 3.5 million years old. Actually 3.85, 3.97, 4.12 and Gramps at 5.193 million years old. Dragons are not very creative because they don't need to be and your cave dwellers are especially uncreative because their quiet cave environment offers no impetus to try new things. Moving into the cave was their one burst of creativity and actually that was all Gramps' idea; the others came along with him. Cut off from the movers and shakers of dragon society as a whole (if there still exists dragon society topside) and with only the 4 of them down in the cave, they continue as they always have. It has worked out ok. There have been some long naps. There are no new dragons because as it happens these four dragons are all dudes. They thought some ladies would be along shortly. Maybe they still will. [Answer] **Your race is very conservative and nature-loving** Intelligent dragons are not like people. They prefer solitary life, see trade as nothing more than a necessary evil, and, above all, protect the state of their natural habitat. Defacing their land is one of the most heinous crimes to them, so, building a factory or a railroad is nearly as bad as killing everyone in a village. Unlike dragons of human legends, those dragons are not drawn to riches. Having enough space, food, and time for thinking is more than enough for their happiness - and they are indeed happy in their caves. [Answer] ## Dragons are mentally incapable of grasping how to read/write This could maybe be explained by severe dyslexia, blindness, or possibly even the inability to mentally comprehend language itself. The big turning point for mankind coming out of the stone age was literacy. For over a million years, man kind's ancestors survived by learning what they could from oral tradition alone. Without writing, it is just as easy to lose knowledge from one generation to the next as it is to gain knowledge. So, you could be the greatest inventor in the world, but with no way to write it down, your inventions can never see wide-spread adoption, and most of them would be forgotten within a few generations. That said, there is one way out of the stone age without writing which is apprenticeship. Here, each dragon can pass on a specialized set of knowledge to the next generation either through spoken instructions or by simply performing tasks to be seen and learned. Each generation will forget a bit and innovate a bit. Unlike a society that has a formal education system, apprenticeship will eventually find an equilibrium where new ideas become so complex that they can no longer be taught without a written record because they require the collection of too many unrelated concepts to orally aggregate in one place. Chemistry for example is the culmination of the works of many great minds spanning several nations over several centuries to be able to come to the kind of system we have today. In an oral society, those men would have never heard of each-other's work; so, instead of building up on previous discoveries, each person's work would be independently lost to the ages. Without literacy, I doubt you could actually achieve Renaissance levels of technology, but you could probably get somewhere in the classical-to-medieval tech level just fine, and then stagnate... only it won't be true stagnation. Knowledge will just be in a constant state of ebb and flow. Some centuries a village might peak at Renaissance levels, then next century it regresses to ancient level tech all because some master blacksmith had a heart attack and died before he could fully train the next generation. Technology will also tend to form and only ever exist in pockets instead of spreading to the whole population. You see this pattern a lot in the history of steel making where various techniques of tempering, quenching, and carbonizing are discovered remain local to an area for a few generations and then fall out of use. [Answer] ## The UNDO program. In a decent magic novel whose name escapes me, the protagonist was a programmer with small magical talent who built up magic spells like programs from small parts. To ensure nothing would go wrong, he designed his magic UNDO program first. The dragons did something similar. They progressed for a few years or a few months, until a magic effect went wrong, and then they used the UNDO spell to go back to how things were before that. They've been doing that at regular intervals ... ever since. [Answer] **Religion/tradition/principles/*evolution*** Technological stagnation has happened before. Although there obviously was scientific progress in some areas, during the European medieval period much groundbreaking work was suppressed by the church, often discouraging or even killing the researchers. But in many other countries, you see slow or stagnant progress. Many African countries had little progress over the years. This can come from too much hardship, little resources, little time/reason to research or tradition, as well as Religion. Your dragons can have a religious reason. Their tradition might dictate their preferences. They might not have the resources or simply see little advantage to continue research as they suppose their life won't be enriched. If you look at western countries depression is very high due to high wealth. But there might be another factor at play. Humans are still very much evolving. There's evidence that our brains get more and more plastic *even in the next generation*. We're better able to understand the problems and build upon them. While at first mathematics was hard for learned people, now it's the standard curriculum for most of the population. Part of our scientific progress might be because of our still-evolving brains. Dragons might not be so lucky. Where humans have doubled down on intelligence, dragons might just have it as a side effect. They are *dragons*. They don't need intelligence to survive, so evolving it further is unlikely. [Answer] ## Degeneration: Your dragons aren't as smart as their ancestors were. Why, after all, should they be? They've been living in a totally stable environment for millions of years. There is no great drive to have tech, and no advantage to having tech. There isn't even an advantage to being intelligent, except agriculture. The time spent learning science and technology is time spent NOT seeking out mates or eating/growing food. The time spent making things is time that could have been spent intimidating your rivals for food and females. It's time you could have spent raising your young (once they get past the grim deterministic youth stage) to be successful breeders and maters. Even calories devoted to growing large brains are calories that could have been spent on a bitch'n set of horns for a mating display. Telling the ladies they should learn how to read is not going to get you mates. Still, the founders wanted everyone to know stuff, and remember tech, and be able to make things. So they imposed their values on their offspring, who grudgingly learned it even though it seemed worthless to them. Now, all this time later, with no drive to make things or know tech, they are like a tribe of natives on an idyllic island with food abundant. Once you get past the grim, deterministic childhood (which the adults seem fine with) life is pretty cushy. knowledge passed on has disappeared like a giant game of telephone. In a very real sense, they live in the land of *Idiocracy*. Of course they prefer ancient ways - they're simpler. Of course they prefer old-style weapons. They understand them. That smart, scrawny smart-alex who made that arquebus got everyone mad at him and they made an example out of him. Those things are really loud in a giant cave anyway. Now the cleverest thing anyone makes are basic tools, cool-looking swords (mostly to show off for the mates) and the occasional crossbow for hunting whatever it is they hunt. [Answer] You need divine intervention It can't be emphasised enough that 3.5 million years is, in historical terms, an insane amount of time. If you want your world's Renaissance Era to last more than 1,000 times longer than the entirety of Earth's human civilisation (even at its most expansively defined), then no amount of conservative social customs are going to last long enough to matter. It is in the nature of all societies to change; consider that China is possibly the world's most stable and long-lasting civilisation, yet in the space of barely 3,000 years it has revolutionised its religious, social, political, and economic make-up multiple times. Certain resource scarcities might work better, but the natural resources necessary to sustain Renaissance-level development for countless generations are not that radically dissimilar from those needed for an industrial revolution. Even if it would take a freakish, million-to-one coincidence or leap of genius for a society to escape the technological bottleneck, over that span of time a colossally improbable event approaches inevitability. Your best bet is therefore probably a magical being or force of effectively god-like power relative to the world's other inhabitants (perhaps the spirits you mention would fit the bill, or maybe something else) which for some reason refuses to countenance railways and mechanical looms but never gets tired of caravels and ruffs. It's pretty handwave-y, but less so than the alternatives. As a side note, you'd still need to consider the implications of a society that's been at a Renaissance level of development for longer than it took modern humans to evolve from apes. What will it be like to have a literary corpus and cultural memory stretching back to when the continents were markedly different shapes? How will people relate to a history which can be measured in geological time? Such a world may have some enforced similarities to our Early Modernity, but culturally and psychologically, it will be a very different place to live in. You'll also have to figure out what happened to recently remove the divine anti-modernity umpire in the first place... [Answer] For some reason, it is very difficult to create durable stores of information in your world. The paper rots, the stone crumbles so easily that carving text into it is impossible, clay tablets don't work because the humidity erodes them over time, and so on. That means if you want to build industrial machinery, you can't just go to the library to find out how an internal combustion engine works, you have to find someone who actually knows how to build one. Hopefully, you learn enough to teach someone else, but more likely you don't really get all of the nuances. That doesn't make it impossible, but your civilization will need to keep an oral history of their technology, which limits the size and the complexity of your technical options. A seaworthy ship is not going to be a problem, but a car probably isn't going to happen (how many people today know how to build a car from scratch?). This opens up two issues/opportunities for story telling: 1. It is much easier to lose technological progress - the only guy who knows how to cure seal skin dies at sea, and the knowledge is lost 2. Longer lived races will be more technically advanced simply because they have more overlapping generations and a wider knowledge base [Answer] A lack of sufficiently energy-dense power sources. The industrial revolution required a huge amount of readily available power. No coal, no oil = no revolution. Because these were readily available in our world, thousands upon thousands of people were working simultaneously to solve problems. In an energy-poor word, maybe 10 are, and they have to be cautious about how they spend it. [Answer] Lack of metals would stymie an industrial revolution. If the iron costs as much as the blacksmith then mass production doesn't happen, screws continue being made individually by hand etc. Take a look at the Roman empire; they had lots of very [sophisticated stuff](https://mccurdyco.com/roman-water-lifting-machine/), but never got around to industrialisation. Consider the role of printing and cheap paper for spreading knowledge. If knowledge is handed down from master to apprentice rather than published and taught in schools then innovation is much harder. Social systems matter. There is no point in innovating and making lots of money if some guy in a suit of armour can come along and take it all off you. Go and watch "[Connections](https://en.wikipedia.org/wiki/Connections_(TV_series))" by James Burke; its full of this stuff. You can find the full series on YouTube. [Answer] **Imprecision** The numina warp things in their vicinity, everything somewhat differently and unpredictably. (Or maybe it's not the numina but some other agent.) I.e. two yardsticks that had the same length today will vary by, say, 1 millimeter tomorrow. The beams of a scale will have slightly different length tomorrow. Your weights be 0.1% heavier or lighter tomorrow. That kind of stuff. Everything medieval still works - houses (wood moves anyway), weapons, armor, carts - none of this requires millimeter precision. Cogwheels? They will work but never be efficient. Waterwheels? That's wet wood, it will work. You can have a lot of low-precision machinery like hammer mills (leather is pretty useful for transmitting power as it is slightly elastic, steel bands won't work so well anymore). Mass production is possible - sort of, anything that requires precision requires human labor. Weaving machines are never going to be precise enough except for pretty crude fabric, and even then it may not be worth it. Taylorism will work (that's how ["manufactories"](https://en.wikipedia.org/wiki/Gobelins_Manufactory) were set up, these tended to have multiple waterwheels in a nearby river, power transmitted into the working halls via leather bands). Quantitative chemistry? Impossible: the beam length will vary so your measurements will not repeat on the next day, i.e. it will be very hard to be sure about anything. (Read up on what made Lavoisier the founder of modern chemistry.) The inhabitants may not even be aware of the situation. The only thing that they observe will be "complicated mechanisms tend to jam on the next day". [Answer] You got some really great answers, but if you're curious of our-world examples, read about China under the Qin dynasty or Japan in the Edo period. Both were an example of the central authority heavily discouraging change so as to preserve the status-quo and out of ideological disinterest with anything beyond their borders. Also, as outlined in many answers, technological progress is not a given, but rather the exception. Previously in history empires would collapse and completely wipe out any progress we made, best example of that is the [Late Bronze Age collapse](https://en.wikipedia.org/wiki/Late_Bronze_Age_collapse), [Classic Maya Collapse](https://en.wikipedia.org/wiki/Classic_Maya_collapse) and [decline of the Khmer Empire](https://en.wikipedia.org/wiki/Khmer_Empire#Decline). Indeed, it is speculated that many of the Greek myths about heroes and titans were inspired by the living memory of the power of those past empires. [Answer] Maybe there is some magical time-loop present, so whenever someone attempts to invent a specific technology, it resets to a certain time farther back. [Answer] # Chaos Magic: The very existence of sapient, intelligent dragons shows us that the world is rich in Magic. This magic alters stuff, on a microscopic level. It gives creatures new abilities beyond the mere physical, but it also scrambles purely physical constructs on the fine level. This causes all precision devices to ever to subtly change over time. Or possibly depending on the level of magical saturation in the location, the sages argue about the cause. Now a sword will not mind at all if it becomes 1/100 of an inch shorter one day, and then longer again the next day. Nor, mostly, will a simple axle for a wagon. Or a wooden waterwheel. But make that same axle out of steel, and fabricate it to hairfine precision that way any *real* machine needs to be, and it will sometimes rattle and other days bind in its bearings. And goodness but you are looking for trouble if you try to machine something as precise as a high-pressure steam engine, or the workings of a firearm more complex than a basic muzzle-loading flintlock, or a truly accurate clock. They *can* theoretically build more modern machinery, but it will simply not be reliable. And the more complex and precise the construct, the sooner it will fail. [Answer] Another possible solution could be "political"; in a way: You mentioned magic exists - which implies, that magic users exist as well. While I don't know the details of your setting, it's likely that powerful mages would rise to political power as well. It could be in their interest to restrict technological advance, either to avoid loss of power or for other reasons that would weaken their position in the long-term. As an example: The game Arcanum gives a setting where magic and technology cannot co-exist and disturb each other. This would be an ideal world where established magic users clearly wouldn't want too much technological advance and may pull some strings to keep it in check. Generally speaking (and depending on how far your magical abilities go), it could make sense for some type of magic courts or groups to either outright prohibit certain technology, or go with anti-tech propaganda. "Machines are evil", "Automation is bad", basically. Perhaps that mentality is ingrained into most cultures by now, after centuries of propaganda. Even easier, since you mentioned this "Watcher": Magicians could claim that machines, factories and the like attract the beast to begin with - even if it wasn't true. Perhaps, they know of a way to attract or provoke it themselves, giving them a scapegoat to target places that refuse to play along - just to prove a point. Come to think of it, that's kind of what happens in Final Fantasy X with Sin. Obviously, this wouldn't be an easy solution for your problem, since it raises many more issues. [Answer] Basically, lack of imagination or lack of resources to realise that imagination… lack of imagination, here, covering whatever strange theory might inspire politicians to try to hold things back as the Roman Catholic Church did during the real Renaissance. What else would be needed, or work? When there was a "paradox" please explain it. No lost caves, caverns or dragons are “paradoxes.” Against a background of millions of years, it hardly matters that the industrial revolution began so long after the renaissance ended, and lasted for less than half the time. How much older than the dragon colonization is your world, and what difference could that make to the Question… except if nothing much happened in the last 3.5 million years, why might anything to worry about crop up now? Don’t you think your denizens might prefer medieval weaponry and customs because that’s what they’ve been used to for millions of years? If it ain’t broke, don’t fix it Do explain what difference magic might make. Do explain what are your main drugs of choice in that world. If the setting being a large archipelago in a mostly temperate zone matters, please say how. If you want fossil fuels, please say whether that’s plain-old coal, semi-industrial unrefined oil or sophisticated derivatives such as petrol or diesel, and why. When there are humans and other races, please say what difference that might make. When you came up with a special monster, please specify to what extent the Watcher, or Numina was “deific” and what difference that made. How god-like does “deific” mean here? While your Numina have been around for a while please instead of baldly stating that you’ve realized how you can apply them to this, explain how! You see, do as you will, that Numina used only to stalk roads at night, killing travellers, but perhaps they can prohibit (other) things as well might be relevant, but only after you’d explained how. Can you re-phrase the whole thing so it's internally consistent, anyway? [Answer] Constant Aurora prevent electricity from being harnessed in any meaningful way. The moon of this planet is extremely geologically active. Volcanos erupt weekly and spew their dust into space where it gets swept up by the Earth's magnetic field (stronger than normal) and forms a flux tube. Like Io and Jupiter this causes constant Aurorae whose charged particles cause electrical surges and destroy any would-be inventors devices. Alternatively, it orbits an unstable red dwarf that has CMEs monthly. This achieves the same effect. ]
[Question] [ A planet with an early civilization (Middle age like) is doomed to be destroyed by an unstoppable event. So an advanced civilization decides to do a planetary evacuation to save the species and their culture, which is staged as an event based on the mythological beliefs of the early civilization to cover their tracks. However, is there a reason to transfer the early civilization into an artificial habitat like an O'neill Cylinder rather than move them to a different planet? [Answer] Convenience, due to multiple and maybe concurring factors, for example: * the cylinder can be brought closer to the rescue place, easing logistic on the evacuation. One thing is moving a lot of people to few light seconds away, another thing if that distance increases. * the planet might have a better use for the rescuer than hosting refugees. What's the point of saving them if then they get threatened again by mines/real estate agencies/etc. * the cylinder can be tailored to contain some features relevant to the mythology of the rescued people [Answer] **You need an artificial habitat no matter what.** The nearest suitable planet for this species is many light years away. Some delicate aspect of this species' biology makes cryogenic preservation or other forms of "stasis" unsuitable, meaning that all members of the species will be awake for the entire trip, which could last decades, centuries, or more. Whether or not you ultimately plan to re-home this civilization on a planet, you're going to need an artificial habitat where potentially generations of individuals will live and die. No matter what the long-term plan is, the first step will involve transferring many individuals to a large-scale artificial habitat. It's a bit like asking why you'd choose an RV to do a long-distance family road trip - it's worthwhile to have on a long enough trip, regardless of your final destination. [Answer] **Biologically incompatible species** There is an incompatibility between available planets and the biology of some/all of the species required for the primitive civ to survive. A constructed habitat is a simple (though likely not easy) solution to that problem. **Ease of access** They might want to do more stuff with the rescued civilization during and after rescue, which depending on the morality of the culture of the rescuers could range from trained enslavement, through extreme-mild research, and over to something like benign integration into the overall larger society. **cultural/moral/political reasons** This is a bit out of bound for the question (you specifically asked about *practical* reasons, but a habitat could be a practical solution to a political problem (for example)). The faction that wants to save the planet ends up using a habitat for the simple reason that they cannot get access to anything else within the time frame required. Or perhaps they were sponsored by ACME Habitats inc. etc. **Wishes from the primitive civ** Again slightly out of scope, but they might have contacted the primitive civ in some manner and put out the options for them, and the choice was to go with the habitat. [Answer] # Entertainment value --- Let's take another point of view on this situation : a primitive civilization will be relocated in order to keep them from extinction. Sure, you could bring them to some planet that already has everything they'll need to start fresh and leave them be. But what about making this "heroic deed" profitable as well? By putting this civilization in a controled, fully customizable environment, you can make them a primary source of endless, cheap entertainment. People love medieval stories, reality shows and so on. With this solution, there's no need to use actors, fictions and the likes. You make the environment from scratch, so anything like cameras, microphones and any other way to spy on them is easy to implement. You can even prebuild some habitats for them, in order to have full access to their full life, 24/7. What about going further? If you have control over the entire environment, you could also create just about any kind of situation you couldn't easily create in a natural world. Having control over the water and food supply, the quality of the soil... You could create wars with minimal effort. Is a group of individuals foiling your plans and potentially ruining your show? Remove them using those convenient "maintenance" systems. With this kind of control, any individual is a "character" you can use for entertainment and marketing purposes. Sure, you could do all that on a natural planet, but it would be much easier to handle a world made for that purpose, rather than having to repurpose an already existing ecosystem. It's all about profit, and what the public wants to watch. [Answer] **Why rescue them?** The aliens value the diversity of civilizations in the galaxy. They want to preserve as many as possible, not as dry databases but as actual, thriving, developing cultures. **Just civilizations?** The aliens also value biodiversity. A civilization might rate slightly higher than non-sentient animals, but they'd rather preserve the animals, too. Any planet that would be a shirt-sleeve environment for the primitives is going to have native animals. **They cannot terraform in an instant.** The aliens have FTL travel, and the ability to build a big habitat on short notice, but terraforming an entire planet is something else. So they want to resuce the civilization, but they *don't* want to disturb other biospheres if they can help it. Fortunately they can help it -- they replace the doomed planet with an artificial dome. [Answer] **It's on the way** Due to speed limits, the nearest suitable planet is thousands of years away. So whatever vessel you use to transport the civilization, it needs to be a self-sustaining ecosystem in its own right. Enter Professor Gerard K. O'Neill and his flabbergasting cylindrizer. [![enter image description here](https://i.stack.imgur.com/djm2r.jpg)](https://i.stack.imgur.com/djm2r.jpg) Perhaps the cylinder is a big space ship that slowly sails to the new home planet. Or perhaps the cylinder stays where it is. Once they built the cylinder the aliens didn't see the point of relocating the civilization a second time. The cylinder is as good a home world as any. [Answer] Practicality & Simplicity. The following assumptions are made in this answer: 1. The advanced race has time to construct at least one cylinder before the extinction event occurs and the science/engineering involved in constructing an O'Neill Cylinder is well understood. 2. The aliens have many ships but they are also spread across many systems and those ships have other responsibilities beyond just trying to rescue this one species, including looking after the needs of their own people. 3. They can't save everyone, even on a planet with a population density equating to that of Earth in the Middle Ages. But they believe they have a moral imperative to save as many of the species and as much of their biosphere presumably as they can. Perhaps some kind of '*life is rare and intelligent life even rarer*' perspective which makes the medieval aliens precious in the eyes of the advanced aliens. Assuming these starting conditions apply and the alien race that needs saving lives on an Earth like planet in metal rich, Sol type star this means the solar system is likely to have abundant resources in space for the construction a cylinder. So they have ample **raw materials** right where they need them. This means *nothing* needs to be transported into the solar system for construction of the cylinder except perhaps for some initial construction / printing and mining equipment. (And maybe not even much of that since the aliens can 'bootstrap' rapidly from a tiny industrial base very quickly.) Say one ships worth of equipment. So once it arrives (assuming they don't already have it) They just locate the largest metallic asteroid they can find and press the 'start' button. Once construction commences no other effort is required by the aliens beyond perhaps construction of the 'drive' they want to attach to the cylinder. (Since there's no reference to how the aliens travel between the stars I've just ignored this issue.) As soon as the cylinder is airtight the aliens can start building the biosphere while work on other essential systems (like the drive) is ongoing. So they can start moving plants and animals up from the surface (with locals reporting lots of mysterious lights in the sky). Lastly they kidnap a selection of medieval aliens and explain what has happened to them if not why. [Answer] A planet? Good heavens, why would you inflict so crude and plebian a dwelling place on them? Of course they were living on one before, but given that you are removing them anyway, what conceivable reason is there to plant them on one of those vast, uncontrollable, and quite dangerous places? The best science in the world can not make the planet quite safe. The primitives might face an ice age, or a drought! No, much more humane to bring them into a place where the habitat is harmoniously controlled by wise minds. [Answer] # Ethics Humans won't see reason about environmental destruction. They won't stop competing to dig up resources to kill each other. The aliens *can't* kill them - it would be unethical - and they *can't* just step in and clean up the planet (the humans would abuse their resources even more, reverse engineer and otherwise exploit the alien technology, and destroy nearby habitable worlds). So there's no way to keep the Earth from dying. Problem is, the honey badgers will die with it. And the aliens know the honey badgers have responded to recent ecological turmoil by evolving sentience and starting the rudiments of civilization. (They may be more trouble than humans, but they're not sure to work *together* to destroy their new planet). The honey badgers *have* to be rescued. Now the aliens could dump honey badgers on a freshly terraformed planet, easy peasy. Except... the species will be denied their normal development. They should grow up in a "natural" environment, and that means not just rich wild ecosystems and a perfect color of sky blue, but running the 3D printers and completely refurbishing the geology of the target planet to show the Descent of Honey Badger with reasonable authenticity. (Some fringe creationist groups will insist there are "missing links" between the time points of the simulated strata, but they would have done so even on a natural homeworld, most likely) Result: honey badgers spend a subjective 40 days and 40 nights zooming from one homeworld to another at a very fast sublight speed on an advanced megastructure, arriving thousands of years in the future to be transferred to a perfectly authentic fake homeworld the aliens have made in the meanwhile. [Answer] ## Capitalism, Colonisation and "Ethics" You want to displace this population and take their planet for your own. Ethical rules and other such inconveniences prevent you from wiping them out militarily. They've equally proven inconveniently resistant to all the diseases you've tried to give them. ## So you generate a cataclysm Offer them an escape, an artifical habitat away from the unfortunate apocalypse that's preventing them from remaining on the planet while you rebuild their environment. You've ticked all the boxes, you haven't wiped them out, you haven't used the army, they have gone willingly, you haven't had to give up another valuable planet in exchange. Unfortunately by the time their planet is suitably hospitable for a primitive tribe, their lands have all been taken over by your industrial expansion. After all, it was a hostile environment with no existing population, so why not. However they're welcome to remain on the habitat with safe controlled weather and no dangerous extremes, no drought, no floods, and no cost to themselves. A round of cost cutting measures, a little neglect, the O'Neill cylinder loses its environment. These poor people never get any luck. An enquiry shows nobody was really to blame, the company gets a token fine and you're home free. [Answer] **Finding a planet for them is harder than you think** It's not actually as easy as you think to move planets. For example, we Earthers have evolved for billions of years to live on Earth in very particular conditions. If we were to move to another one, it wouldn't be good enough to simply go and find another oxygen planet with liquid water. The gravity would have to be similar, we would need similarly low levels of CO2, I'm sure there are many other gasses which would be deadly, or extremely uncomfortable to us if they were present even in trace amounts. The climate, soil, etc. would have to be right to grow the food we eat, there would need to be plenty of water that is not contaminated with any chemicals or microbes that are dangerous or unhealthy for us. A similar magnetic field might also be required or highly recommended. Now let's take your primitive race. You probably want to keep them as pure to their origins as possible - i.e. not using technology or any sort of body modification or drugs to help them adapt to their new habitat, going by the question it seems you don't even want them to know you exist. It's probably easier to create an artificial habitat which can replicate their original conditions - i.e. those most suited to them - than it is to find a planet which matches their requirements closely enough. [Answer] Outside of space opera, FTL isn't going to happen, and interstellar travel is hard. A "realistic" interstellar civilization is a mesh of systems connected together with lightspeed communication networks. They can still have ridiculous technology levels and even extend over galactic clusters without it being cheap to move large amounts of mass between solar systems. They expand by sending star wisps -- tiny craft -- to new solar systems, which in turn build an entire civilization in that solar system (connected back to the old one via light speed communication). Uploading and downloading of life forms to digital representations is trivial, so even interstellar travel is possible; you just don't move your body. When such a civilization finds a more primitive one that they want to save, building or even finding a new planet is going to be hard. I mean, they could copy them and upload them; but doing so isn't very polite to someone who doesn't consent. (uploading a copy and killing the original still kills the original). Building a space habitat is much cheaper than building an entirely new planet. The kind of problem that they couldn't block (cheaply) might be a supernova going off nearby. They build the habitat and shield it with the planet. When the supernova fades, the planet they used to inhabit would have its biosphere destroyed; the advanced civilization can then start reprinting a biosphere, while the rescued civilization lives in a orbital habitat. After a thousand (or maybe million? I don't know how hard terraforming is) they can then move the rescued civilization back to the planet. In a modern sense, this would be akin to identifying an endangered species next to an exploding volcano. Taking that species and keeping it alive in captivity during the explosion, then rebuilding the habitat as best we can, reintroducing the species to that habitat over time until it has recovered. Finding a new habitat is harder (more expensive), and riskier, than trying to breed it in captivity. In the near future, we'd also try to backup the species with a record of its DNA and attempt to artificially produce copies of it (maybe in related species), but that would be a backup attempt. [Answer] Life basically is divided into growers (plants) and eaters (animals.) Growers have a very low energy budgets, almost certainly incapable of supporting civilization. Thus the race you're trying to save is an eater. Eaters require an ecosystem to eat and an atmosphere that can be reacted with said ecosystem. Effectively, this means a world with an already-existing ecosystem and you probably have to seed it with a **lot** of lifeforms to make it metabolically compatible. Providing that is going to be a lot harder than just moving the species in question. No world without an existing ecosystem will have a suitable atmosphere--it's the product of life. (On Earth this would be oxygen, while I wouldn't say animal life must be oxygen based there has to be something and it takes energy to create.) Thus moving them to another world is simply not viable. It has to be an engineered habitat. [Answer] # It's not the only planet doomed to be destroyed by the same event. If it's just one planet in the system, and they have a few years to plan, they could always commandeer any of the other, potentially uninhabited planets; especially if they're in the [Goldilocks Zone](https://en.wikipedia.org/wiki/Circumstellar_habitable_zone) - though if you're able to evacuate a whole planet, you could just plan to move another planet into the same orbit once the event requiring evacuation happens, you could just terraform that planet, and be generally good to go. Sure, the system's down a planet, but as long as you can keep it on the down-low, that seems reasonable. As long as there *are* other planets in the system. But what if we [up the ante](https://www.youtube.com/watch?v=hTc9sLmOR0A)? After all, if there are *no* other planets in the system, then getting them to another galaxy would take a while, or finding a suitable planet nearby might take more work than is helpful. So you get them on an artificial habitat, and get the habitat out of there either with fair warning ahead of time of the event in question, or as the event begins and in a...bit of a rush to get them out of the system. This might actually help with the mythological beliefs being used to cover your tracks - just, well, without staging anything if you're actually still leaving while the event is in progress. [Depending on how similar their early civilization is to ours](https://en.wikipedia.org/wiki/Planets_in_astrology), you could get away with just letting them be able to see the event as they're escaping the actual event. Given some time, "I saw Pluto explode!" becomes "Pluto and Neptune got into a fight a while back" after a few years, and...that could get wrapped into a mythology with not a lot of trace for anyone who investigates well after the fact. [Answer] # The Once and Future Home World: Let us assume a cataclysm bad enough to wipe out life, but not actually blow up the planet. Your native population will be destroyed by the cataclysm to come, but you either don't have the means or are ethically restrained from moving them away from their home system. Maybe they technically OWN their home world. Maybe every habitable planet is reserved for whatever intelligent species evolves there first. Maybe the mythology says they get to return to their home after the apocalypse. In a couple thousand years (a blink, really) their world will have recovered from catastrophe and be ready to be repopulated. So what to do? You move them to a set of orbitals in their home system (maybe even over their home planet). They orbitally rendezvous periodically to allow genetic exchange, but are separate to prevent a single catastrophe from wiping them out. The sun looks the same, the plants and animals are preserved, and you don't have to drag them all very far. You use local materials (after all, the locals own the asteroids you build the orbitals out of) so you don't have to drag stuff from somewhere else. They can look down from the heavens and see when their planet begins to green - at that point, it should be ready to re-colonize. **And** at that point, your responsibility to these people is done. You've saved them, left them with their own world, and even given them the landing ships to repopulate when the world is ready. I mean seriously, you don't want to be on the hook taking care of them forever, do you? ]
[Question] [ So I'm creating a sci-fi book, and I'd like to know a way to calculate how fast would the moon need to spin to create a certain amount of gravity, and how much energy would be required to get it to spin that fast. I couldn't find any information on this on google. If you do answer, please provide the calculator/equations you used to calculate the mentioned information. Okay, I see some people misunderstood my question. I know artificial gravity can be "generated" by rotation. What I meant was, how fast (RPMs) would the moon need to spin in order to achieve the Earth's gravity for any underground habitats. So that anyone living in those underground habitats would experience gravity similar to Earth's. Something similar to hypothetical rotating space stations, except in this case, the entire moon would spin, so that anyone living in it's underground habitats would experience Earth-like gravity. [Answer] $$ F=\frac{mv^2}{r} $$ That's your equation. Let's flesh it out. m is the mass of the human, in kilograms. Let's call it 75kg (around 165lb). F is the sum of the weight of the human on earth and the weight of the human on the (non-spinning) moon, in Newtons. This is because centripetal force due to a spinning planet (or moon) will act in a direction opposite that of gravity from that planet (or moon). Call it 735N in earth-weight, for just over 120N moon-weight (close enough). F = 855N. r is the radius of rotation, in meters. The radius of the moon is around 1738100 meters at the equator, where we'll be building our base, for maximum velocity. r = 1738100 meters. Now we just have to solve for velocity: $$ \frac{Fr}{m} = v^2 $$ $$ \sqrt{\frac{Fr}{m}} = v $$ Substitute in our variables: $$ v = \sqrt{\frac{855\mathrm{N} \* 1738100\mathrm{\ meters}}{75kg}} $$ And solve: $$ v = 4451 \mathrm{\ meters/second} $$ The circumference of the moon is 2×π×radius, or 10920804 meters. So, our moon would complete one revolution every 10920804/4451 seconds = 2453 seconds. That's roughly once ever 40.89 minutes. That's not so unreasonable, right? But here's the catch. Anything at the equator of this moon on the outer surface, going at the speed of the equator, will be launched out into orbit. That means moon dust, rocks, spacecraft, everything. The moon will disintegrate, and the underground base with it, if you can even find a way to build the base in the first place (maybe before speeding up the rotation). The escape velocity of the moon is only 2380 meters/second, and the equator is clocking 4451. So, no more moon. The solution to this is to make the moon stay together by some incredible binding force of essentially magical strength. If every molecule was immovably bound to every other, you could have your base. Whether that works for your story, I don't know. Note: You'll run into this problem on any planet of any size, when you try to make its centripetal force greater than its gravity. The equatorial speed will rise over escape velocity, and the planet will disintegrate. That's why artificial gravity of this sort typically only comes up in space stations, which aren't kept together by gravity at all. [Answer] Such a high rotational rate would cause the moon to shatter. Not only would the rotational rate have to exert enough centrifugal force to cause people to experience 1.2 G while on the ceiling of a cavern, it would have have to over come the moons natural gravity. At that speed objects such a rocks and lunar regolith to leave the surface and fly off into space. It would probably be high enough to cause the lunar bedrock to break apart and also fly off into space. [Answer] **Bah.** I want a giant spinning habitat on the moon! If we can't spin the whole moon that fast without having the rocks on it lift off (which makes sense, I grudgingly accept) we will construct a habitat on the surface of the moon and have that spin. Now, how fast? from <https://rechneronline.de/g-acceleration/centrifuge.php> [![screenshot from Gforce calculator page](https://i.stack.imgur.com/S1uee.png)](https://i.stack.imgur.com/S1uee.png) So if my habitat makes 0.025 revolutions in a minute that means 1 revolution in 40 minutes. The circumference of the moon is 3,476,000 meters. That means in the habitat we are going 86900 meters in a minute. That is 5214 km/hour. Oh that is fast you say. Too fast, oh my. Things will break. The ship canna take much more. Pish posh I tell you! This is the moon! There are no pesky bugs to splat on the windshield. And we have a maglev track. The rotating habitat will be spinning like a fashionable belt about the midsecton of the moon. You will have to get up to speed before you get on. There will be special places to do that. [Answer] **An intuitive explanation** If you're spinning the Moon, you want apparent gravity to point away from the core, into space. That's fine, except that it's not only your habitat which experiences that apparent gravity. Rocks on the surface also "want to fall", and if things are falling away from the core ... the rocks will "fall" into the sky. That becomes a runaway process, in fact - anything which "falls away" reduces the mass of the Moon, decreases its gravitational pull, and lets more material pull away faster. (This is a mix of escape velocity and the [Roche limit](https://en.wikipedia.org/wiki/Roche_limit).) See also [this](https://en.wikipedia.org/wiki/Gravitational_binding_energy). Such a disintegration was a plot point in part of the *Long Earth* series. --- There are two interesting ways to handle this. One is to glue the surface together, but at that point you might as well build your own habitat - even the risks are the same. The other is to **core the Moon** and put your habitats inside, then have them rest on the stationary rock above to not fall into space, which supports the rock at the same time. You'll want a frictionless set of rails. The precise dimensions will affect your needed speed, but that's given by the centrifuge-calculation answers. [Answer] *Wayfaring Stranger* gives you the math on why your idea is impractical (impossible, without super materials). A more practical way to use rotation to increase apparent gravity on the moon, would be to have rotating habitats in the shape of a frustum (cylinder with one end wider than the other; much wider in this case). Basically you would embed a misshapen O'Neil Cylinder in the crust of the moon (narrow end down) so that the combination of the force of gravity from the Moon and centripetal from from the rotating habitat align and result in an apparent 1G within the habitat. [Answer] So this has kind of already been addressed but here we go: The problem with the question is that centrifugal force is the opposite of gravity, in that increasing the centrifugal force of the moon would lessen gravity. In order for this to work, the people in the caverns would need to be standing on the ceiling of those caverns. If you think of references to this in media such as Interstellar, Cowboy Bebop etc the part of the space station that has gravity is the outer wall but *only* on the inside, with a person's feet pointing toward space and their head pointing to the rotation point. This makes sense too, take a string/belt, hold it over your head and spin it - the centrifugal force pushes outwards. The other part as mentioned by others is the stress placed on the moon's surface. Needing to bind the surface together would probably be the first issue to be addressed. ]
[Question] [ [![enter image description here](https://i.stack.imgur.com/GvIN8.png)](https://i.stack.imgur.com/GvIN8.png) [![enter image description here](https://i.stack.imgur.com/v7d7J.jpg)](https://i.stack.imgur.com/v7d7J.jpg) Recently got inspired by chinese wushu martial arts movies and I wanted to implement a little bit of what I saw into one of my fantasy worlds. The idea was to make a lightweight spear-rapier hybrid type of weapon for my some of my fantasy world's elite soldier. (armor having gone out of fashion) The shaft of the weapon would be pretty much like a bo-staff while the tip/blade would be made out of a thin razor-sharp, extremely durable and flexible/wobbly material. It would be designed to do damage from thrusts and slices using the strength of one's muscles rather than momentum. This would be for more theatrics (impractical jumping, back-flips...etc) and overly dramatic fast-paced fencing, users would be able to collide/clash blades at a distance without having to get too close except of the occasional colliding of shafts for dramatic effect. --- Also on a less important note and unrelated to the main question at hand but for additional information. Since my world is fantasy I was personally planning on making the metal the tip/blade of my spear-rapier hybrid's are made out of be able to heat up with momentum eventually turning it into a "heatblade" with sufficient time/momentum, this in order to counteract the inherent weakness of these type of weapons against armor. [Answer] The basic weapon you're looking for to marry to your bo staff is the [urumi](https://www.youtube.com/watch?v=rkOgQCl9jrI). This is basically a sword that is razor sharp, and more importantly for the martial art you're considering, *razor thin* as well. As you can see, the urumi, with its flailing blades and some amount of uncertainty where they're actually going makes this a terrifying weapon. And that's just for the warrior wielding it! Imagine facing someone flailing one of these things around! (They are actually carried by men in parts of India, and form the basis for one of that country's more astounding martial arts.) So, why not just snug the handle of an urumi onto the end of a quarter staff! Allow me to introduce the *kshwanna*, a curious weapon wielded by crack warriors in a world near you. [Fig. 1. Preparing for the Attack from Below to Above:![enter image description here](https://i.stack.imgur.com/tnkjM.jpg)](https://i.stack.imgur.com/tnkjM.jpg) As you can see in figure 1, the crack warrior is positioning his *kshwanna* low for a surprise attack. His opponent is momentarily baffled by the presence of his wing, which like the tassels on many kinds of weapons, is being used as a visual block and a distraction. [Fig. 2. The Attack is Carried Through Successfully:![enter image description here](https://i.stack.imgur.com/Nldpg.jpg)](https://i.stack.imgur.com/Nldpg.jpg) As you can see in figure 2, the attack came as just a bit of a surprise to the foe, as the wing was drawn back, revealing the terror of wicked sharp flails rapidly approaching. The foe has been caught off guard and is now suffering from multiple injuries: part of his ear has been sliced off, one eye has been destroyed and long gashes can be seen upon his torso. While the wounds made by the *kshwanna* are not usually deadly in and of themselves, the cumulative effect is often shock and weakness from blood loss. The blades are not able to stab, but a strong jab from the quarter staff itself can knock a foe off his feet. The blades can, however, slice off fingers, noses, ears, and other bits, which is also true of the urumi upon which this weapon is based. The *kshwanna* is rarely used in battle against earnest enemies. Rather, it is a showy weapon wielded by skilled warriors during flamboyant and exciting martial arts exhibitions and contests. [Answer] What you describe is in essence still a spear, and it’s arguably not a good one. To understand why, you have to understand the practicalities of the construction of a spear versus those of a rapier. ### How a spear is built and why it works. Note that I am considering an actual spear here, not a javelin. The general construction of a spear is a relatively compact piece of hard material (usually metal or stone) on the end of a relatively rigid pole (usually made of wood). The details of this construction are actually kind of important to understanding the fighting style. In particular: * The head is very compact relative to the rest of the weapon. This allows it to be kept light without sacrificing durability, which allows for better control when thrusting (compare to many other polearms, where the head is a significant portion of the weight of the weapon and for which thrusting attacks were inefficient compared to other options) while still avoiding significant risk of the head itself breaking. * The shaft is (usually) constructed to have very high compressive strength along its length, typically at the cost of durability perpendicular to the length of the shaft. This allows for even better thrusting attacks, but means that using the shaft to block is usually a bad idea (which is why so many traditional fighting styles using a spear either use a shield with it, or emphasize dodging or deflecting/redirecting over blocking). * The binding of the head to the shaft is a potential weak point on the weapon. It’s got to be durable enough that shock loading won’t cause it to come undone, but in general it’s still the most likely part to break unless the shaft itself is attacked directly. The combination of the very compact head and the structure of the shaft means that it can be optimized, however, to simply have good compressive and tensile strength relative to the length of the shaft, and most historical designs were built like this. This leads to a case where striking a spear head as it’s thrust can often easily knock it off the weapon (or knock it out of alignment with the weapon, which will cause it to break off the next time you try to thrust at something). All of this leads to a relatively simple to construct and simple to use pole weapon optimized for thrusting strikes. ### How a rapier is built, why it works, and how it’s different from a spear. At its simplest, a rapier is a short sword (typically about 1m to 1.3m long) with a thin (often 3cm or less at its widest) double edged blade and an often complicated guard. The blade itself is often at least a bit flexible due to its small cross-section perpendicular to its length, and the overall weapon is light, but not exceedingly so when you consider it rationally (typically about one kilogram). Similar to a spear, details of the actual construction are important to the overall fighting style. In particular: * The tang (the un-sharpened metal at the opposite end for the blade from the tip) extends the full length (or almost the whole length) of the grip and is in some way locked in. This is a crucial part of making *any* sword a viable weapon, because it makes it almost impossible for the blade to become separated from the grip. This is also, notably, a drastic difference from a spear, where the norm is either a short tang no longer than the head itself, or a locked collar arrangement (similar to how the heads of most farm implements are affixed to their handles). * The blade itself has to be specially made. The very edges have to be rigid enough to retain their sharpness and not get dented just because of hitting something but soft enough that they won’t just chip or shatter if you hit something hard, and the rest of the blade has to be flexible and springy enough that striking something hard won’t just snap the blade. This is in stark contrast with a spear head, which instead of being flexible relies on its relatively compact dimensions relative to its volume to maintain its structural stability and is a lot less picky about the exact properties of the material it’s made of. * Due to the short effective range of a rapier, you need a guard to protect the hand. This isn’t needed at all in a spear, so we can kind of ignore it for the purposes of this discussion, but it’s important to understand that the guard also served to help balance the weapon effectively. The reason a rapier works so well for highly agile combat styles (same for many other fencing swords as well as other thin blades with complicated hilts) is that it has more mass right by where you are controlling it from than anywhere else in the weapon. This gives very precise control, at the cost of not being able to hit as hard. ### OK, so what about a rapier on a stick? What you would get is not a spear, and would not be wielded as such. What it would really be is something along the lines of a glaive, fauchard, naginata, or guandao, but with a very thin blade. Such weapons are generally not great for thrusting attacks, but are *very* good for sweeping strikes. The problem though is that if the blade is thin and flexible like a rapier, it’s actually going to be too fragile for this type of usage. On top of that, sweeping attacks are pointless unless there’s momentum behind them, because you have to overcome momentum to get them started in the first place (essentially, the lighter a weapon, the shorter it should be if you want it to hit effectively, because you need to put more force directly behind the strike to get the same net impact as you would with a heavier weapon of the same size), and if you get momentum behind it, the impact load on the blade will be enough that it just snaps unless you’re *super* careful with it. Now, there are some other designs you could look at that might be better for what you want, but they don’t involve flexible, rapier-like blades. The terms you want to look for are ‘sword staff’, ‘svärdstav’, ‘partisan’, ‘langue de boeuf’, and ‘ox-tongue spear’. All of these describe spear-like weapons that had longer double-edged blades as heads instead of the shorter points many westerners associate with spears these days. They could all be used for both slashing and piercing attacks, and retain most of the benefits of range that a spear would give you, at the cost of some agility due to being heavier (both for durability, and to allow more momentum behind a sweeping attack). [Answer] **1st bad news**: momentum doesn't cause change in temperature, energy does. That apart, you don't want the metal of any weapon to get too hot, because any metal getting too hot either loses its functional properties or will start creeping. Take a nail and start bending it back and forth. Do it long enough and it will break apart and you will notice it has also gotten noticeably warmer in the point were you have bent it. **2nd bad news**: if you don't use momentum you are drastically reducing the efficiency of your weapon. $F\cdot \Delta t = m\cdot \Delta v$ tells you that the more change of momentum you have, the more force you can exert in the same time. **3rd bad news**: a shaft designed to be flexible and bend won't allow you to exert any appreciable thrust. It's a basic engineering knowledge that any lean structure when loaded on the tip will buckle. Try with a raw spaghetti and see. If you want to be realistic and accurate, I would say your weapons is ill designed and not very practical/effective. [Answer] As a rule, unless the weapon is entirely magic (in which case, it can look like whatever you want), the answer is simple: # Was A Similar Weapon Used in Human History? If the answer is no (as in the case for a spear with an extended, flexible tip), then it's probably impractical. If a weapon would be relatively straightforward to make (strapping a rapier to a staff just involves some rope), and yet *wasn't used*, then it isn't practical. Weaponsmiths weren't uncreative in human history. Your stated goal of making [flynning](https://tvtropes.org/pmwiki/pmwiki.php/Main/Flynning) practical is also unlikely, because sound and fury signifying nothing is not something any fighter wants. They will opt for a weapon that foregoes the clashing in favour of "end this fight now". [Answer] Physics isn't on your side here. You want "overly dramatic fast-paced fencing". The reason you can get that sort of thing with a fencing foil is that they are lightweight and balanced, with the weapon gripped near its center of mass (large, ornamental pommels were often cleverly-disguised counterweights). The weapon that you've designed is essentially a [polearm](https://en.wikipedia.org/wiki/Pole_weapon) of some sort (I'm imagining an [ahlspiess](https://en.wikipedia.org/wiki/Ahlspiess) with a more flexible blade). Polearms were primarily used for three things: throwing ([javelin](https://en.wikipedia.org/wiki/Javelin)), thrusting attacks from a safe distance ([pike](https://en.wikipedia.org/wiki/Pike_(weapon))), or using the shaft as a lever to increase striking force ([halberd](https://en.wikipedia.org/wiki/Halberd) or [woldo](https://en.wikipedia.org/wiki/Woldo)). The physics that make this class of weapon so useful for that third use case are the exact same physics that will make it almost unusable for yours. A spear/staff has a shaft that is of relatively uniform density. The center of mass is therefore at the midpoint of the staff, far from the place where the users in your first photo are gripping it (the Bo staff is typically gripped with hands on either side of the center of mass, balancing it). This makes it *much* more difficult to control when used as in your first image, as you're essentially on the inefficient end of a lever. As an example, try closing and opening a door from the doorknob side. Easy, right? Now, grab the inside edge of the door, just above one of the hinges. Try to swing the door closed (slowly) and while it's moving, try to stop it and change direction. See how that's *significantly* harder to control and takes far more force than using the doorknob side? Swinging a staff/spear like a fencing sword will take significantly more strength, and the weapon will have so much intertia that it will be hard to control and easy to predict and parry with a lighter weapon. Plus, a small movement on the user's end will translate into a much larger movement on the business end. This means it will be almost impossible to control well enough to make targeted thrusts (attach a pen to the end of a broom handle and try to write with it). The second photo is a *bit* more practical. The left hand is near the center of mass, allowing it to be used like a pivot point. The tip would follow the right hand in speed and magnitude, only mirrored. This reduces your range quite a bit, though, because you have to be able to physically reach the center of mass (which is actually beyond the midpoint due to the heavy blade on the end). Plus, your body gets in the way of the back end of the staff, limiting your movement options. Each swing still imparts a lot of momentum that has to be cancelled. Even an unusually strong fighter wouldn't be able to make those sorts of movements quickly enough for the sort of action that you're envisioning. The reason that you can have fast, flashy sword fights is because the weapons are agile. Fencing is about quick reactions and precise strikes. Long, heavy weapons are fundamentally unsuited for that sort of fighting. The closest thing you might be able to get would be a spear-like weapon whose blade could be removed and used like a short sword in close-quarters combat. This fits in line with many historical weapons used by peasants, which were often improvised by [attaching bladed farm implements onto the end of a long tool handle](https://en.wikipedia.org/wiki/Guisarme). [Answer] **From one perspective, it's no more or less practical than a traditional spear** You have a long staff with a metal tip. You're modifying the tip a bit, but it's still just a metal tip. Spears, lances, etc., have never been slashing weapons as there's not enough weight to seriously damage the opponent (please take that for what I mean... think "I can't cut the guy's arm off with a spear, but I could with a sword!"). They've always been stabbing weapons. And since you're attaching a stabbing point to a stabbing weapon, there's no practical difference. **On the other hand, what's the point?** My first reaction was to think the leverage of a lengthy staff would bend or break the rapier tip. However, there are a number of weapons both European and Asian that have lengthy tips (halberds, guandaro...), meaning leverage might not be an issue. So the real question is... What's the value of a flexible tip? The staff itself already serves the same purpose of the flexible rapier: to produce movement that harder to counter. The flexible tip won't be substantially lighter than most spear points (especially given the aggregate weight of the staff and the tip). So I really can't think of a reason why a rapier tip would be a benefit. But it could be a liability. Armor might be declining on your world, but that doesn't mean some hard object might not get in the way. In fact, comparing your rapier-spear to a traditional spear, a bit of light armor would likely tip the balance in favor of the traditional spear. [Answer] **That weapon isn't going to be very good** A rapier does damage by the rotation of your hand causing the blade to whip around, cutting skin and going through the opponents guard. You use this to do slashing style attacks. A spear does damage through the strength you can put into it's thrust, and the speed and control that can be done with a rigid shaft and both hands. For a strong thrust, you want a mostly rigid blade, although some flexibility can help prevent it breaking. You also have slashing spears, like the Glaive, however if you look historically, the blades used for these were rigid and strong. This is because a piece of metal on the end of a long shaft is heavy, and due to physics, swinging it takes a lot of strength, and therefore is hard to bring back for a second strike. So you either want them to back off and give you time, or die. A rapier on a spear end, would combine the worst of both worlds. You have a thin, slashing/cutting blade that needs to be moved quickly and score repeated small hits on a weapon that you can either thrust or do long sweeping swings with. Not ideal. [Answer] ## The closest practical weapons was the Japanese Naginata [![enter image description here](https://i.stack.imgur.com/quBQn.png)](https://i.stack.imgur.com/quBQn.png) The Japanese actually used weapons very similar to what you are describing (minus the magic heat blade thing.) [Naginata](https://en.wikipedia.org/wiki/Naginata) were a very common type of light polearm sword thing during the 11-12th century AD. Most of the time the blade was slightly curved more like a katana or sabre than a rapier, but if you are going for an authentic Japanese feel, the weapon should have a curve. The metalurgic techniques used in Japanese bladesmithing actually cause the blade to curl back during the heat-treating process; so, even if a Japanese smith were to forge a straight sword blade it would normally end up with a slight curvature when it was done anyway. The reason I suggest you go with the Naginata is that it was a light weight polearm designed for quick thrusts and stabs which will fill the role you are looking for quite well. There are plenty of Youtube videos out there of Naginata dueling that are very fast paced and "flashy" much like a rapier duel would be. That said, what you should never expect out of a Japanese blade is flexibility. The Japanese were not as good as the Europeans or many Near East civilizations at making spring steel; so, their blades were typically thicker and sturdier relying on using bimetallic carbon steel layering and single step temporing for strength instead of homogenized crucible steel with multi-stage tempering. This made their blades very rigid in comparison. When a Japanese blade gets bent, it stays bent; so, you could substitute a Naginata blade with something thinner and more flexible, but it would be somewhat anachronistic. ## ... or the Ahlspiess (frame challenge) I suspect you actually meant a sabre based on your description, because the rapier is a thrusting sword and very unsuited for cutting even though your question asks for that, so if you want a polearm that is more literally a rapier on the end of a spear then the Ahlspiess would be your weapon of choice. A big part of the reasoning for the evolution of rapiers was that cutting blades like sabers were not very effective against light and medium armor like gambison or chainmail. Since even peasant soldiers had at least a gambeson by then late medieval period, thrusting became a far preferable method of attack. While the Ahlspiess and Rapier look like flimsy weapons they both have blades that are thicker perpendicular to the edge than broader bladed but similar weapons. This makes them more spike like than blade like so they are actually surprisingly stiff blades despite not looking like it. The idea of rapiers having a lot of bend is a common misconception based on modern fencing foils. Fencing foils are made very flexible on purpose to prevent injuries, but historical rapiers did not bend any more than a broadsword because they needed enough rigidity to punch through through these armors. Yes. they were made of spring steel so they could flex very far without breaking, but it takes a good bit of force to actually do this. [![enter image description here](https://i.stack.imgur.com/MjM91.png)](https://i.stack.imgur.com/MjM91.png) ## Many other similar weapons [![enter image description here](https://i.stack.imgur.com/seBZs.png)](https://i.stack.imgur.com/seBZs.png) There were many other historical weapons that could be described as swords at the end of a polearm. This includes sword staffs, bradeches, glaves, etc. but these weapons were typically much longer and heavy hitting battlefield weapons designed to be used in pike squares rather than fast dueling weapons. [![enter image description here](https://i.stack.imgur.com/VgQ7N.png)](https://i.stack.imgur.com/VgQ7N.png) The cutty-stabby dueling pole-arm of choice in Europe was the short-staffed Halebred, but these are in many ways the opposite of what you want. They swing with tons of inertia making them great at killing through heavy armor, but they were not what you would consider nimble in the way that a rapier is. ]
[Question] [ <https://en.m.wikipedia.org/wiki/Albertosaurus> Going to have my male human protagonist kill an Albertosaurus with stone age weapons. However as this is in self defense I was just curious to know how one would go about doing it. For context the two characters have been sent back in time to late Cretaceous Midwest America. They're lucky to have found themselves in a situation that they have a semblance of surviving. Nevertheless surviving a year in this hostile environment is going to be difficult. I want to have my character fight an Albertosaurus because I believe that that's the largest carnivorous dinosaur and animal they can reasonably kill in the 70-66 MYA era ( <https://en.m.wikipedia.org/wiki/Maastrichtian> ) Taking down such a large creature with a spear is different to doing it with a bow and arrow. Still in this situation what would be the ideal way to kill a healthy, adult Albertosaurus that is, at most, forty meters away? [Answer] **Pit Trap** [![enter image description here](https://i.stack.imgur.com/2GV7U.png)](https://i.stack.imgur.com/2GV7U.png) Dinosaurs are big and heavy. Big heavy things are more vulnerable to falls than small light things. A three foot drop will not harm an ant. A person falling into the pit will be fine unless they land awkwardly. Or there are spikes at the bottom. You do not need spikes. A dinosaur falling into a garden variety hole in the ground will break a leg, die of dehydration and be eaten by scavengers. [![enter image description here](https://i.stack.imgur.com/uFqJ1.png)](https://i.stack.imgur.com/uFqJ1.png) Gotcha. [Answer] **Drive them over a cliff.** Obviously, this is a situational and risky solution, but still one to take into consideration: the mass of the Albertosaurus won't allow for rapid changes in direction. If they can be lured (e.g. with meat of smaller animals) towards a deadly precipice, especially while charging (at a dummy prey, or, in a pinch, at one of your time-travellers) with 20 km/hour, they can surely be defeated. [Answer] ## Fire Making fire will be a key survival step. Once fire is made, it must be preserved, because using a [fire drill](https://en.wikipedia.org/wiki/Fire_drill_(tool)) every night is exhausting. So your survivors will need a [fire pot](https://en.wikipedia.org/wiki/Fire_pot#Early_times). Assume that they also carry suitable torches, or that dry wood is available. Light the torch, wave it and shout, and *hope* that this unusual spectacle panics the dinosaur. Herd the dinosaur into a ravine. [Answer] **A pit trap** Have your characters dig a hole deep enough to cause the animal to fall in far enough to injure itself. Albertosaurus was a maximum of about 10m meters long but only 3-4 meter in height. So dig a pit at a natural choke point and draw the animal into it. It only has to be 1-2 meters deep! As long as it is broad/wide enough to ensure the animal will fall in depth doesn't really matter. The animal weights 2000 kilos plus after all! You line the bottom of the wide but shallow pit with sharp stakes every 20 cm or so. Then lead/coax the animal into charging across the covered pit. Immediate death isn't the goal merely crippling injury. If the Albertosaurus can't hunt it's doomed. [Answer] Since it's in self defence I'm assuming you don't have time to dig a pit that big and line it with sharpened stakes and bait. I'd distract it and basically herd it to an area where I have an advantage. A sling is great for this sort of task. You don't sling at the animal you sling in the direction you want a predator to go. They follow the sound instinctively. Or you sling opposite to where you want to herd a non predator and they move away from the sound instinctively. This is the reason shepherds used slings, they still do in the Andes and I think the middle east. 40 metres is an easy range, I can sling over 100 metres without trying too hard. [Answer] An Albertosaurus surprises the hero (heroes?) from 40 meters, and then charges them - I presume. Two plausible ideas for them to kill it: The most logical way for the two of them (or maybe just one) to kill something that big, is to run in a direction which has something that the humans could get through, but the dino would get stuck in - two trees, narrow passage in a rock formation, etc. If they stay close enough to its head to keep it enraged, and have some sort of weapon, they could eventually take it out (poke its eyes out, cause it to bleed out, etc.) I don't see, in the wiki reference, anything about the *width* of an Albertosaurus - but maybe you can find that somewhere. > > One test of animal intelligence is the ability to 'go away from food, to get to food' and not all predators have this level of intelligence. > > It seems plausible to me that a dino wouldn't have this level of intelligence - or if it did, that it would not exercise it while food (your heroes) is within reach > > > An alternative is for them to run near a cliff / ravine / natural bridge. When the dino runs a similar path while pursuing them, its massive weight causes some sort of collapse in the earth. The collapse causes the dino to break a back leg, or tips the dino over where it either bashes its skull or hits its skull hard enough to stun/immobilize it. While it is immobilized, the hero knifes an artery in the neck, cuts the tendons in its back legs, or whatever works for you. A horse can break a leg by stepping in a gopher hole. A less heroic kill could come from an Albertosaurus who broke a leg running. Another negative to this is you'd need a prehistoric giant gopher (or whatever) hole to be in the right place - but you're writing the story so if that works for you, I'd believe it. If you didn't plan for the Albertosaurus to charge them, they could taunt it into charging them. This gives your heroes the added advantage of planning. Why they'd taunt something with banana sized teeth is beyond me, but I'm sure they have a good reason :-) [Answer] Learn from the Ewoks <https://www.youtube.com/watch?v=N3C5GN15kas> * two logs smashing together * logs, rocks tumbling down a hill * trebuchet (or similar) * snare [Answer] **A Well-Placed Arrow/Spear** There are already some fantastic answers. However, it might be less thematically sound to have the largest theropod dinosaur in your story being taken down by a simple pit or fire. To fix this, I suggest a more "interesting" method that is less practical. Albertosaurus, unlike some dinosaurs, has an *Antorbital fenestra* which is a large opening in the skull that houses the sinus'. If an arrow or spear where to make its way deep into the Albertosaurus' skull via this opening, it has the potential of seriously disrupting its sense of smell. Since most large theropods rely upon their sense of smell to hunt for prey, a dinosaur with a compromised snout is not going to survive long in the wild. [Answer] It is entirely possible for humans to bring down very large animals with a spear. Especially if they use an atl-atl to add power to their throw. The proof in this is the general disappearance of megafauna (predatory or otherwise) soon after the arrival of humans in any landscape. Like somebody else mentioned in another similar question, if the animal can bleed out, there is not really any size limit, assuming your protagonist can start the bleeding somehow. There's a lot to assume there, but all of that lies outside of the scope of the question. They'd probably have to get lucky, especially if they haven't been throwing spears their entire life. For your plot to work, do they have to kill the dinosaur? Can they run and hide somewhere until the predator gives up or more suitable prey comes along? [Answer] **Run, then make the trap.** You won't be making trap if it is 40m away. Humans can run/walk very *very* long distances, they are also very agile compared to a dinosaur. If our guys are in a forested environment, even an average person will be able to dodge and outrun a dinosaur until it tires out. Then do whatever you like with it. [Answer] ## Use a Barbed Spear While a Mammoth may not be quite as aggressive as an Albertosaurus, they were much larger, and harder to kill, yet this did not prevent our stone aged ancestors from hunting them. Cave paintings show many different hunting methods that worked, but most of them required you to either work as a group, or prepare a trap in advance, but there was one hunting method that was relatively safe, only required 1 hunter, and needed very little prep work. The hunter would hide in a tree overlooking a known mammoth trail and thrust his spear into the mammoth from above while remaining at a safe height above the it. The key here is in how these spears were designed. Unlike a military spear where the head has smooth blades for easy extraction, hunting spears were napped or had added barbs such that they would go in easy, but be very hard to take out. What this would mean when hunting large animals is that you only needed to land one strike a few inches deep, and then let go of the spear. Then when the animal inevitably panics and tries to run away, the action of moving around works the spear deeper and deeper into the prey until it pierces something important, and kills it. So, lets apply this to your Albertosaurus scenario. Your hero is out hunting and spots the Albertosaurus. Knowing that the Albertosaurus is a terrible climber, your hero decides to climb a tree and wait for the Albertosaurus to pass on, except that the Albertosaurus notices the human and goes to investigate. The hero being terrified and not quite sure if he's gotten high enough to be out of harms way is forced to turn and fight. As the Albertosaurus tries to figure out how to reach the human past all the tree limbs, it exposes the side of its neck or torso not realizing how dangerous of prey this tiny human can be; so, the hero thrusts his spear into the exposed bit and lets go knowing better than to try to extract it. Now the Albertosaurus is a hunter too, not a warrior. It will only pursue a hunt if it believes the hunt is worth the risk; so, it will react the same way any predator would react to being unexpectedly stung. It will fall back, at least long enough to reassess the threat of the prey and try to decide if it's still worth it. But that moment where it recoils is where your human is given the opportunity to keep climbing until he is surely too a safe height. So now, even if your Albertosaurus decided to try again, as it moves around trying to figure out how to get to the human, the spear will go deeper and deeper, and hurt more and more. Eventually, the spear will either work its way into an artery or vital organ dropping the dinosaur then and there, or the building pain will cause it to try to get away from the human, which will have the same basic effect in very little time. Regardless, it only takes 1 barbed spear to kill very large prey, you just need to be able to get somewhere safe enough to not get eaten while you wait for the spear to do its job. [![enter image description here](https://i.stack.imgur.com/j5SrA.png)](https://i.stack.imgur.com/j5SrA.png) [Answer] ## Poisoned arrows Use a strong poison like Black Mamba venom, [a few grams](https://www.quora.com/If-a-black-mamba-was-to-bite-a-T-Rex-could-its-neurotoxic-venom-eventually-bring-down-the-large-dinosaur) will suffice to kill a Rex. The Rex you'll have to shoot in the mouth. The Albertosaurus would be easier: it was smaller (less body weight) and as mentioned above, it had an open skull, providing easy access to brain tissue, vulnerable to nerve agents. ]
[Question] [ Militia Y intends to burn massive amounts of wood in order to produce carbon monoxide to be used as an air contaminant in warfare. **Defence**: to be asked as a follow-up question. **Time period**: ancient (140 AD thereabout). **Plan**: Arrive at battle site long before enemy arrives, Settle massive load of wood in strategic places. The rest lies in the bows of the archers (with flaming arrows of course). **Transport**: Carried by massive griffins (on platforms tethered with steel chains). **Although!** Militia Y would prefer to test a recent [theory that wet wood produces more carbon monoxide](https://www.hunker.com/13419014/what-happens-when-you-burn-wet-wood-in-a-fireplace) **No worries**, [carbon monoxide also poses a health hazard in ventilated areas](https://www.ncbi.nlm.nih.gov/m/pubmed/9456553/), thus, there might be feasibility of open air carbon monoxide poisoning. **However, realistically, is this strategy** a little too fantastical, even for a fantasy world? [Answer] This will be totally ineffective in any open environment with a terrestrial atmosphere because [carbon monoxide is lighter than air](https://healthybuildingscience.com/2013/02/22/carbon-monoxide-facts/). As such any amount of CO produced will rise into the atmosphere away from the battle. Only in a confined space like a cave could this be considered as a weapon, where fire is already an extremely effective combat tool. [Answer] Any fire big enough to produce a useful amount of CO will also produce its own circulation. The heat of the fire will cause air to rise over the fire, and bring surrounding air in at the bottom. The bigger the fire, the bigger the effect. So the fire itself will drive the CO away from the location of the fire and disperse it. Also, the evidence of many millions of Boy Scout and Girl Scout camp-outs is that fires do not tend to produce dangerous levels of CO near the fire. I have never heard of an outdoor situation in which there was any possible CO problem. Long before the CO gets you, the other components of the smoke and gaseous combustion products of the fire will get you. The moment you get some kind of enclosure you can have significant problems. It would not take much. The bottom of a deep bowl-shaped valley might accomplish something if it was a very still day. The fires would have to be small and distributed around so as not to create large updrafts. But probably not from the CO, more likely from the CO2. Or if you could lure the opposition into a cave or similar situation, you might get enough still air to have some effect. [Answer] **Burn your wood for the smoke, toxic and otherwise.** If you like the idea of burning lots of wood, go ahead and burn it. Especially wet wood will make a lot of smoke and smoke is a legitimate asphyxiant. Probably better than carbon monoxide because smoke makes you cough and choke, and also you cannot see your enemy - who you know must be there because her troops (including massive griffins and who knows what else) showed up enough ahead of you to set up all this smoke. It might be possible, with smoky fires and medieval tech, to add other things that would be better chemical weaponry than CO. If you burn poison ivy (I think burn in a relatively cool fire) some of the oil gets aerosolized. Breathing that will seriously mess you up and can even kill. Breathing a little bit and coughing a lot will make you even more scared of the smoke. Your troops can throw bales of poison ivy or your world's equivalent on your fire once the enemy starts advancing through the smoke. [Answer] This could work under one circumstance: militia Y is burning a plant with toxic/irritant properties, such as poison oak/ivy/sumac. (One problem fire fighters encounter with wildfires is encountering smoke produced by one of these plants burning. Get this irritant in your lungs, & if it isn't fatal the victim sure wishes it was.) However as others have pointed out, this is not very practical. When armies in WWI used mustard gas in battle, they found it difficult to manage: all it took was one unexpected breeze, & the poison would blow into friendly ranks. And there is the challenge of finding enough of this plant to be worth the problem. As user535733 commented, your militia would be better off bringing armor & pikes than poison plants & wood to burn. [Answer] I think such an action could be easily defeated. If I remember correctly Pliny the Younger describing how the Romans dealt with the eruption of the Vesuvius also wrote that they used cloths drenched in water to protect themselves from the smoke, that wasn't enough for Pliny the Elder, but it should be enough against a man made fire. ]
[Question] [ In my world, [hypnotism](https://en.wikipedia.org/wiki/Hypnosis) is both powerful and reliable. With a few tools and a lot of suggestions, it is possible for trained hypnotists to put people in a trance-like state. While in this state, the victim will do almost anything the hypnotist's ask. Experiencing pain or being startled can knock a person out of a trance. Obviously, politicians would be a high value target for hypnosis. This is because a hypnotized politician could either really embarrass themselves and end their career or they could be manipulated for domestic/foreign purposes. If powerful mentalists were around, how could politicians and other very important people make sure that they don't wind up being manipulated and saying/doing something that they shouldn't do? Edit: How hypnosis works is that a hypnotist performs some repetitive action like swinging a pocket watch or stirring a glass while the subject watches. The hypnotist then keeps suggesting that the subject relaxes and stays calm. After about 3 minutes of this, if the subject is compliant, they get hypnotized. The tricky thing is that sly hypnotists can hypnotize people over the course of a casual conversation without the subject realizing it before it is too late. The sly hypnotist could just perform a minor repetitive action and get the subject to remain calm until they're in a trance. [Answer] # Life is pain ### (anyone who says otherwise is selling something). The answer is **pain**, which disturbs hypnosis. In every world, technology develops in part to supplement or provide abilities we ourselves do not have. Our distant ancestors invented textiles to replace absent fur, and knives to replace claws. In the present, we supplant failing hips with titanium, support immune systems with antibiotics, and aid hearts with pacemakers and implantable cardioverter-defibrillators. If we lived in a world where we did not have these problems, these technologies would not exist. We *do* live in a world where we are not vulnerable to hypnosis, so anti-hypnotic tech does not exist, but it could. I propose an implanted monitor which tracks brain waves. When they match the induced hypnotic state, it shocks the bearer enough to either wake them from the hypnotic state, or prevent them from falling into it. Naturally, every serious politician would have one, but they’d likely be almost universal, just like vaccinations. What sane parent would send a child out of their sight without one? [Answer] /In my world, hypnotism is both powerful and reliable/ **Pre-emptive strike** Your politicians are all hypnotized by powerful and reliable hypnotists to ignore hypnotic suggestion. In your world this worked better than expected - politicans not only paid no attention to hypnotists but also ignored in person suggestions, information and complaints by lobbyists and constituents. Information and new knowledge obtained by hypnotically protected politicians was all through reading. Information was thus much less biased by the communication skills (hypnotic or no) of persons advocating one or another policy choice. The inability of hypnotically protected politicians to listen to other people did cause them some trouble at home. [Answer] **Be Old as B\*lls** [![enter image description here](https://i.stack.imgur.com/tedSu.jpg)](https://i.stack.imgur.com/tedSu.jpg) Politicians are mostly old crotchety men. Against all odds this turns out to be a good thing. You see young people are vulnerable to hypnotic suggestion because they have a storm of new thoughts popping off morning noon at night. It is hard to distinguish what thought they came up with the one that was hypnotically implanted in your brain. Old people are different because they are essentially robots. And you cannot hypnotise a robot. Everyone knows it just cannot be done. These withered old dinosaurs are ossified and operate on auto-pilot. They seize up if they have to do anything fundamentally new or answer a question they were unprepared for. Fortunately they have been around the block so many times they have their reactions prepared for anything that might happen. Only they will react the same way as they did 20 years ago. Usually by talking about the budget for fifteen minutes while being careful not to say anything specific. That means if a rogue thought pops up it will be noticed immediately as the first thought they had that day. Then the training kicks in and they report to their handlers for reprogramming. Even if the implanted thought does sneak through, the victim will likely not have the secondary skills to carry it out. If Senator Oldbones is implanted with the message to assassinate Speaker Fartface at todays congress, then he is stuck because he doesn't know where to find a weapon. He knows where the knives are kept at home. They are in the knife drawer. Unless they are dirty. The dirty ones get put away and then magically reappear the next day. But he is not at home today. He is in the Senate house. This leads to him either driving home in the middle of the day, when he should be on the floor, or wandering the halls mumbling to the custodial staff about how he needs to butter some bread. Both strange behaviors are picked up on and the senator is sent back for reprogramming. Hooray! [Answer] **Politicians are very good at passing laws that protect politicians...** If you think about it, what protects politicians from angry gun owners? Yes, there are those few gutsy crazies like [John Hinckley Jr.](https://en.wikipedia.org/wiki/John_Hinckley_Jr.) who will take the risk and try to step past the defenders, but for the most part, the traditional protection works remarkably well. *Law.* Whether we're talking about your local department of transportation hiding whether or not they're going to bypass your town with a new freeway or your local potentate's critical national secrets, the reality is that a hypnotist can do a lot of damage if a lot of damage weren't being risked in return. So it's reasonable to assume that politicians would pass laws making hypnotism of any public official a [capital offense](https://www.law.cornell.edu/wex/capital_offense) little different from any other act of treason and punishable by death. Save in the cases of the crazies and the *incredibly confident...* problem solved. **Notes:** 1. You don't explain how hypnotism works in your world, so there's no way to explain what the politicians can do to physically defend themselves. We can always throw out vague things like, "they train mentally to resist hypnotism," but that doesn't say much and doesn't add much to the rules of your world. 2. Insofar as I understand hypnotism, it isn't like radio. The hypnotist must be present and within visual and audible contact of the target. Thus, bodyguards will also add to the politicians' protection. 3. If hypnotism is as powerful as you suggest, most communities would be investigating how to employ hypnotism as part of their judicial process. Nations would be employing it for espionage and spying. In the process, a great deal would be learned about how to defend against the very weapons those municipalities and nations are employing. **And finally...** If hypnotism were that powerful, average citizens would be losing their life savings to unscrupulous hypnotists. The legal system would very quickly begin licensing hypnotists, regulating their activities, and an entire suite of laws would quickly come to pass making hypnotists horrendously liable for what they do. If this doesn't sound a bit like the laws governing gun ownership, you might not be paying attention. As the Good Book says, where much is given, much is required. [Answer] ## Guards It's always useful to have someone watching your back. You might not be aware of being hypnotised, but people around you will probably notice. Many politicians are protected by personal bodyguards, secret-service, mercenaries or just plain policemen. These individuals may be trained to watch for the signs of someone being hypnotised, or the kind of language and behaviour that leads to it. The role of bodyguard may therefore not end at the physical security, it may include the security of their charge's mind too. ## Fortification and counter-hypnosis. Hypnotism is most effective against the unwary and unprepared. A vital public official (or worried joe-punter) might engage the services of a trainer to teach them to defend their minds against this. This would start with Mindfulness and Awareness of what's happening, and at the extreme upper-end, incorporate small hypnotically implanted micro-suggestions which act to shock the person out of whatever trances they may be entering. The politician might start slowly slipping into the trance, and then abruptly snap out of it with whatever warning-signals they have implanted in their subconscious ringing hard. They'd then know the person in front of them is attempting to hypnotise them, and can act accordingly. **Narrative Improvements** For purposes of narrative interest and the need for things to not be perfect, this hypnotic defence-layer might interfere with the ability to actually sleep, every time you start drifting off to sleep, you'd snap to wakefulness with mental alarm bells ringing due to the false-positives. To deal with this, a person with this system in place might need to go through a series of nightly rituals. Sitting in front of a mirror and repeating a code-phrase three times, or wearing their Sleep-Amulet. Basically disarming their defences for the night. This may make them vulnerable if they're accosted in the night by a hypnotist, or fail to reactivate their defences in the morning for some reason. [Answer] Several possibilities (likely all of them will be used): 1. Legal. The same way politicians are protected from assassins - by making murder a serious crime with grave enough punishment to deter almost everyone from killing your politician, no matter how you hate him/her/them, and making police investigation throw *a lot* of effort into murder cases. 2. Sunglasses. 'nough said. (Now I wonder why sunglasses are so popular in the USA and why USA is the dominant country on Earth) 3. Optical distraction. Assuming plain sunglasses do not work, wear glasses with minuscule mirror specks embedded in them - as you make tiny head movements, they generate flashes that distract you enough from falling into the trance. 4. Concentration distraction. Wear [uncomfortable dress](https://en.wikipedia.org/wiki/Suit), not uncomfortable enough that you cannot do your work, but enough that you cannot relax. This might extend into corporations, top level management just *cannot afford* wear anything else, and the more important they feel, the more likely they are to [order their employees to wear](https://en.wikipedia.org/wiki/Dress_code) such dresses as well. Politicians that wear [more comfortable](https://commons.wikimedia.org/wiki/File:%D0%97%D0%B0%D1%8F%D0%B2%D0%BA%D0%B0_%D0%A3%D0%BA%D1%80%D0%B0%D1%97%D0%BD%D0%B8_%D0%BD%D0%B0_%D1%87%D0%BB%D0%B5%D0%BD%D1%81%D1%82%D0%B2%D0%BE_%D1%83_%D0%84%D0%B2%D1%80%D0%BE%D0%BF%D0%B5%D0%B9%D1%81%D1%8C%D0%BA%D0%BE%D0%BC%D1%83_%D0%A1%D0%BE%D1%8E%D0%B7%D1%96,_1.jpg#/media/File:%D0%97%D0%B0%D1%8F%D0%B2%D0%BA%D0%B0_%D0%A3%D0%BA%D1%80%D0%B0%D1%97%D0%BD%D0%B8_%D0%BD%D0%B0_%D1%87%D0%BB%D0%B5%D0%BD%D1%81%D1%82%D0%B2%D0%BE_%D1%83_%D0%84%D0%B2%D1%80%D0%BE%D0%BF%D0%B5%D0%B9%D1%81%D1%8C%D0%BA%D0%BE%D0%BC%D1%83_%D0%A1%D0%BE%D1%8E%D0%B7%D1%96,_1.jpg), [less oppressing dress](https://commons.wikimedia.org/wiki/File:Muammar_al-Gaddafi-2-30112006.jpg) might be often pulling short straws. [Answer] Shift social expectations and political norms. In the real world, many women are [scared](https://www.theguardian.com/commentisfree/2021/apr/06/women-are-scared-to-enter-politics-because-of-their-past-i-was-one-of-them) to enter politics because they fear that some grumpy ex will send their nudes to the tabloids. There are legal ways to counteract this fear, such as making the tabloid legally culpable for prosecution, but the photo could still be submitted to anonymous Internet sites where such laws are hard to enforce. What really needs to happen is to shift social norms. The default response should be to blame the leaker and consider the woman a victim. If hypnotism is a real risk in your world, a similar pr effort will be needed so that instead of "pervy president took his kit off at the State of Union" the general discussion is muted tones of "poor man!" with perhaps a good hearted "honestly, I hope I look as good at his age!" That's key for the pr side. The more important (to the country) practical question is how to avoid a hypnotised President doing something terrible- declaring war on France perhaps. For this, the answer is the same as without hypnotism. Structure the government such that no individual or sufficiently small group to get compromised is able to take such consequential action unilaterally. This won't solve everything, but it should help any other suggestions. [Answer] **Monitoring** They will undergo some hypnosis sessions and the characteristic patterns of blood pressure and pulsations will be measured. Then they will carry a bracelet and another sensor to constantly monitor the state. If an hypnotic status is detected a small electric shock will wake up the politician. ]
[Question] [ Set in the medieval period the one where King Arthur was supposed to obtain a certain quest reward from lady of the lake. Magic strength in this universe depends on species and most importantly the affinity that ones had been born with, humans seemingly spanned both ends of the spectrum. An enchanted weapon is crafted by bestowing a regular weapon with a magic property, you can only have one magic property on a weapon and subsequent enchantment will rewrite the current magic property regardless of talent. Given the high trading value of metal at that time why aren't people recycling those enchanted weapons? Note that durability of a weapon is only affected by colliding with another object or a nasty foe so theoretically there is no upper limit for applying new magic properties on a weapon. Recycle: rewrites magic property of enchanted weapon. Reforge: melt down the metal and then make into new one. Reuse: switch between ownership Repair: self explanatory [Answer] It's simple economics. Once a weapon is enchanted, it's a much better weapon in some respects. The thing is, weapons aren't normally judged on a wide-ranging, complicated scale. The enchantments people will pay for will all be more or less the same - supersharpness, unbreakability, flame generation, soul reaping, etc. Once you've acquired one of these weapons, there will be a ready buyer for it. So why bother adding a new enchantment? EDIT - as a result of a comment by Hobbamuck, I should point out that there is an alternative. In my original answer, I've assumed a sort of common-sense Swords and Sorcery approach to the question of what "enchantment" means. This is by no means certain. Let's say that there are a million Demon Realms, and a weapon can be enchanted to be powerful only in one realm. If I'm going Adventuring in a new realm, it would be natural to want my weapon to be enchanted to be powerful in that realm - but with a million possibilities it's unlikely that there would be a weapon on the market which has the enchantment I need. Particularly if the base (unenchanted) weapon is more expensive than the enchantment, it would make sense to purchase the enchantment I need for the mission at hand, rather than conducting a long search to find the one I need. [Answer] Assuming an ideal spherical free market in a vacuum, recycling becomes rare if we go by these axioms: * An enchanted sword is worth more than the same weapon without an enchantment. * Magicians seek to make a profit. A magician who decides to sell enchanted weapons must acquire weapons to transform. It only makes economical sense if the output of the process is worth more than the input, by which I mean that a wizard must sell their weaponry for more than the price of the weaponry they bought (plus labour cost and any magical materials consumed). Replacing an enchanted sword with another enchanted sword does not bring the wizard profit, so they must be using unenchanted swords if they want to stay in business. One could bring up the fact that multiple enchantments exist and some may be more valuable than others, but in a free market the value is inversely proportional to the supply. Ergo, there must be fewer wizards who can make the enchantments that are worth a lot - else every sword would be equipped with the desired enchantment over time, making the price drop. That means that a minority of weapon enchantments involve sword recycling, for it is only even an option for the high-end wizards, and they could make greater profit if they started from an unenchanted weapon. This only changes when swords are in such short supply that there are fewer weapons than magicians, but that would make unenchanted swords worth more than enchanted ones and break the entire business model of an enchanter. [Answer] **There's more incentive to NOT re-enchant a sword than you might think** Swords are a dime-a-dozen. They're made by the thousands for the military. Swords are *everywhere.* It's almost as if you can't swing the proverbial dead cat without hitting one. And since there's no benefit to enchanting a sword twice, there's no motivation to do it. In fact, one could say that there's motivation to ***not*** recycle magic swords because that minimizes the amount of magic in combat. Think about it. Your thousand-man infantry could have a thousand magic swords, or one sword that's been recycled a thousand times. What's the motivation to recycle that one sword? There is none. So there's nothing really about magic swords that make them less desirable for (re)enchantment, it's just that the world is a better place when you don't do it. [Answer] > > Note that durability of a weapon is only affected by colliding with another object or a nasty foe so theoretically there is no upper limit for applying new magic property on a weapon. > > > Clearly this is not so. If people are adverse to recycling enchanted items, it would be because overwriting an enchantment degrades the physical or mystical properties of the materiel. (See experiences in early magnetic data storage media where you could record over a tape a limited number of times before noticing a decrease in quality.) [Answer] The enchanting works along the same line of the fingerprint identifier available on some smartphones: it activates only when the legitimate owner tries to use it, else it doesn't. And in this case Pommegranate INC., which patented the enchanting process, has no economical incentive in allowing a second user to access the item, preventing them from lucrating on the royalties. The process leaves a permanent trace in the metal, and it has been shown by experience that overwriting leads to unwanted effects. Even worse if the overwrite happens with a different bearer. [Answer] Because magic **won't** be overwritten. If someone tries to overwrite an enchantment, the result is instead a dual enchantment. Sometimes this is helpful, other times not so much. 1. Worst Example: Let's say you have a Sword of Fiery Fury; it's as hot as if it just came out of the forge, so it tends to ignite and/or burn whatever you hit it with. However, since you've realized the innate problems with this, you want that enchantment overwritten by Fearful Aura (the weapon inspires fear through its presence) instead. Instead, you get a sword that swings and pulls *itself* around (violently) to hit everything within range. Oh, and it burns and/or ignites everyone and everything in range *except* you. You can only sheath the dang thing after the battle's over (ie. after all the enemies are dead or aren't enemies anymore) and so you only take it out as a last resort. Best Example: Once again, you have a Sword of Fiery Fury. However, this time you want its enchantment overwritten with Frigid Fury (extreme coldness). You end up with a Sword of Furious Frostfire, which releases icy blue flames on impact, igniting the area (what it hit). These flames spread, burn, but otherwise act like ice, freezing (and therefore immobilizing) the unfortunate victim. In other words, your enemies will end up disintegrated, leaving behind a crystalline formation of frigid flames that burn and freeze to the touch in their image. Eerie and effective! Since recycling is therefore impossible, people think very hard about the enchantments they put on their weapons and only go for "overwriting" when they want a new fusion enchantment. New enchantments can be added, you just can't overwrite or otherwise remove already held enchantments. [Answer] ## Psychometry: Psychometry is the magical principle that objects take on the emotions, auras, and impressions of the things around them and the people that use them. So if a man buys a magical sword and uses it to fight a war, there are his feelings of hate for his enemies, the suffering of the dead, and possibly those of his own violent death. Who knows, part of someone's soul may be stuck in there. So you go and decide you want to inherit your father's sword. If he used it, there's some dark stuff associated with that thing. For a non-magical weapon, no big deal. But dark impressions are a lot harder to get rid of than the mere enchantment that opened the weapon to a larger world of magic. The more powerful the weapon, the more violence that goes with it. Maybe you fight the same enemies your father fought. Fine. Maybe your father loved you and his own feelings towards you are safe. Okay. Are you certain of that? Are you willing to trust a soul-draining weapon in battle with all the hate and anger and death associated with it? Have fun. So try to reenchant the sword, and those negative impressions don't go away. They are soaked in like a stain. Melt it Down? Maybe you can burn out the taint in the fires of the volcano it was forged in, but otherwise good luck. As for repair, during the lifetime of the owner, the weapon is MAGICAL and is unlikely to need repair. And if it does break, maybe it's because of some really bad vibes that have soaked in. Maybe you're better off just mounting that thing impressively on the wall and getting a new one. But maybe not where the dripping blood and screams of the victims will mess up the floor or disturb anyone's sleep. [Answer] Sometimes it goes boom. If a weapon has magic on it and you try to add more magic or seriously alter the metal (reforge) then it produces a very big explosion. So to recycle/reforge you first need to remove the existing enchantment, but the technology to do that isn't perfect and leaves some non-removable residue behind depending on factors like how long the enchantment was there, the strength of the enchanter, etc. Depending on the amount of residue it has a chance to go boom when you try to add the next enchantment. If you repeat this process the residue accumulates and the chance of boom goes up. The exact point where it will go boom isn't able to be accurately measured and even guessing how much residue will be left after removing an enchantment is very complicated. So no one wants to try re-enchanting your old family sword that you swear has only had one enchantment since new because if there's too much residue then it's pretty likely that their workshop will become a pile of splinters. You probably don't even want to remove the old enchantment because it's at least something, whereas if you remove it and no one will re-enchant it then you only have a pointy metal stick. To reduce the number of magical suicide attacks you can say that once enchanting starts you can't move the weapon and enchanting takes a while with a big, obvious setup. Likewise, it's going to be difficult to take a forge into the middle of an enemy encampment and start heating up a sword to reshape it. But you do have some myths where a king hundreds of years ago was able to reforge a high-residue sword into a dragon slayer in the hour of need, etc. (And maybe a small industry of research wizards with heavily armored workshops in remote locations and no eyebrows who experiment with pen knives and subtle enchantments, trying to create formulas to accurately calculate how tightly an enchantment is bound and predict if a weapon will be re-enchantable.) [Answer] **Enchanted items are very expensive and thus often protected by a curse for their commissioner. Bloodline curses or password-esque curses are very common to accomplish this.** For example, a rich Lord might have a set of enchanted armor with a bloodline curse that burns anyone not from his bloodline on skin contact. This way, not only can rightful progeny be easily screened, but thieves and other miscreants are discouraged from killing or stealing from young noblemen to obtain their magical items because they'll be crippled by the curses on them and would be unable to use or fence them. Similarly, an adventurer might have a magical sword that bursts into flames but only when the wielder whispers the command phrase. This command phrase can be something very obscure or even nonsensical and this discourages theft and having the weapon being turned against them by people who don't know this 'password'. Unfortunately though, over time curses can weaken, conditions can change, and knowledge can be forgotten. If an adventurer dies without passing on the command phrases or activation keys to their magical items, they become expensive magical paperweights. Similarly, an improperly done bloodline curse might deteriorate in functionality when the bloodline of the original owner gets too diluted several generations down the line. This means that wealthy or traditional families often have large vaults full of magical items that they can't use because they can't figure out the command phrases or their curses have made them entirely unusable over time. [Answer] Enchanted weapons are either 1) never given up, 2) made by the gods. In the latter, the power dissipates because their purpose has been served, so no one regards them any more. [Answer] ## Old enchantments never die, they just go somewhere else When a sword is recycled/re-enchanted, the old enchantment is not actually *overwritten*; rather, it is *cast out*. After being expelled from the sword, it becomes a free-floating blob of invisible magical energy, seeking a new object that it can latch on to. This is generally a bad thing. * Recycle a frost sword? Oops, your well is now a block of ice. * Flaming sword? Goodbye, thatched-roof cottage. * A sword that strikes fear into the hearts of your enemies? Now the bell around your cow's neck makes you too terrified to milk her. * Supernaturally sharp sword? Guess what, the magic went into one of your teeth and you bit your own tongue off. Swords *can* be properly disenchanted without unleashing the old spell—it's a bit like unpicking a knot—but it takes a skilled magician and a good deal of time. And if the magician screws up, the energy backlash can melt or destroy the blade. It's a lot less trouble to just start with a fresh sword. [Answer] In our world, technology gets better as time goes by so disposing of or recycling of our technology makes economic sense - because you aren't going to want to have a 100 year-old computer (can't run Doom on a Colossus). Traditionally, magical worlds reverse this - magic gets worse over time (lost knowledge, men are weaker in spirit than their ancestors, magic is a non-renewable resource, etc.). So older magical artifacts tend to be more powerful than what can be created today, which means more effort is put into guarding and preserving versus recycling. Now, in your world maybe that isn't true. Maybe magic is getting better. That might be fun - whole armies having to buy new magic swords every three years because two-year-old swords are really borderline pathetic against the new models. Then you might have to enforce recycling so the landfills aren't filled with old magic items, just dangerous enough if civilians find them, but no danger to someone with modern defensive magics. [Answer] "rewriting" the magic item has a higher cost than the metal. This "cost" can be any of a number of things: * Ages the "rewriter" by 20 years * Rewriting takes years longer than just enchanting an unchanted item. * The replaced magic manifests itself as a highly toxic, corrosive acid vapor, likely to destroy everything around it * The replaced magic may have a hidden magical "trap" that fires if it is replaced. * etc. etc. etc. [Answer] Why is any of that difficult? From time immemorial up to around 18-1900 most accounts of the aftermath of battle include details of gleaners gathering up everything from the corpses’ teeth to, yes, full suits of armour and weapons. Why would they not reap that rich harvest, however horrid? Given the high trading value of metal at that time doesn’t your Question Answer itself? Either people would be “recycling” everything to hand, or they’d see enchanted weapons as something special to be treated differently… more likely, both. Here, to be treated differently might mean find a specialist gleaner, prolly an enchanter? Why is any of that difficult? [Answer] so if i understand correctly, they basically get enchantment that they already want in the first place right? since they can order it base on their desire or suitable talents, the chance they change their mind is unlikely especially regarding melee weapon that they are used to or master with and they choose that certain enchantment for a reason. it also can take a while to train your body to get used or accustom with this new enchantment. sure you may encounter someone that is a bad chemistry with or has advantage against your martial style or enchantment or unit formations/compositions and force you to use another magic enchantment, but as @JBH has mention its far better to enchant blank slot weapon than rewrite the magic of the original weapon, and you may want to use back your old enchantment back later against the others, also now you have two weapon that can work as backup weapons or combine their magic enchantment with. to explain better why i say you likely need to train your body to get use to the new enchantment of your weapon, imagine you originally use fire sword you likely know the safety movement to make sure the fire or heat dont reach or blow over your face or use proper armor for it and your body likely get use to the heat, outside of knowing how you can control your movement to use the fire to damage your opponent, to fast and you may lose the heat, but still it fitting with/become your martial style. and then you change to electricity, you need to learn a new safety to make sure you dont get electrocute yourself, it likely different than your previous one and require fitting armor against such element too. or if the enchantment boost your physical ability such as speed or strength or maybe make the weapon heavier or lighter, you need to train your body control and timing or perception to get use to that, especially if it boost your speed or manipulate the weight, otherwise it may ruin your balance or stance or you may accidentally overswing that can make vulnerable opening to yourself or make your weapon stuck to deep to pull out, or weaker swing that can result in less lethal damage or not deep enough cut to your opponent, because how light or how heavier to you, outside of your embedded muscle memory or habit not fit for this certain enchantment that can end up injure you. after all we are talking about weapon here, its not just costly economically to do so, but it also can cost your life or your pride (if we talk about nonlethal duel) and time. ]
[Question] [ From [Giant in the Playground Forum](https://forums.giantitp.com/showthread.php?310029-Temperature-of-Dragon-s-breath-weapon-%28fire%29-or-I-guess-cold-too): > > Well a Great Wyrm Red breathes hot enough to theoretically ~~liquify~~[melt] 4 > inches of solid iron across an 80 foot or so line. So an 80 foot wall > of iron 4 inches thick could be ~~liquified~~[melted] by a single attack by a > Great Wyrm Red. > > > > > the end result is that the air breathed out by the dragon [onto the iron reaches] 1520 > degrees Kelvin, 1246 degrees Celsius, or 2276 degrees Fahrenheit. > > > Can an umbrella be used to deflect a breath from the dragon, and also keep its average human user alive? If so, what materials would it have to be made of? It must still be light enough for an average person to still raise. Assume the umbrella is a small personal umbrella, with at most 60cm radius, with a surface area of roughly 2.25-2.5 meters squared. This happens in a low-fantasy world, with some magic, but still has similar physics. Edit: to better support yes answers, seeing as the d&d dragon’s breath is far more deadly than expected, you can assume the umbrella can activate magic, but only to turn the umbrella into a sphere/semi-sphere around the user. Edit2: Due to an error made in calculations by the source on the temperature of the breath, we now have some inconsistencies for temperatures mentioned in some answers. We will assume 1246 degrees Celsius for this question (enough to melt ductile and cast iron), as all of the answers mentioning higher temperatures of 1500 degrees scale linearly, so this does not invalidate any of the premises. [Answer] **Yes**, but... You can probably construct an umbrella which deflects and protects that which is immediately behind it from immense heat, however, without a thermal protection system like a thermal suit, anyone in the vicinity of such heat would probably roast simply by proximity. For example, there's [NASA's ADEPT program](https://www.nasa.gov/centers/ames/orgs/exploration-tech/projects/adept.html) where they developed an unfolding heat shield: [![ADEPT](https://i.stack.imgur.com/i6JZm.jpg)](https://i.stack.imgur.com/i6JZm.jpg) And here it is in a hot-air wind tunnel: [![In hot air](https://i.stack.imgur.com/JxIWT.jpg)](https://i.stack.imgur.com/JxIWT.jpg) Adept's TPS system is mostly constructed out of woven carbon fiber layers with a rigid central shell. [Answer] ### Umbrella vs a kiloton nuclear warhead. Even ones made of unobtainium and blessed by all the gods will be vaporised in an instant. **Lets take a look at that wall melting, and try to work out the power in the dragons breath** So, melting point of iron is 1538 degrees C Lets assume Earth global average temperature at the spot the attack happened (15 degrees C). Irons specific heat capacity is 444 J/kgC. Irons density is 7874kg/m^3 Your wall that was melted was 24.384m ('80ft') \* 10cm ('4 inches') \* ...? Assuming the wall is a standard [medievil fortification](https://en.wikipedia.org/wiki/Medieval_fortification) the wall height was 2.5m minimum. (But it could be up to 6m). We're going 2.5m here just to give the umbrella the best chance. So we have $24.384 \cdot 0.1 \cdot 2.5 = 6.1 m^3$ of iron. The wall weighs 48031.4kg. So to heat that wall by one degree, you need 21325941.6 joules of energy. ... But we need it heat it up by 1523 degrees. So the energy contained in the breath is: 32479409056.8 joules! That number means nothing, so I suggest refering to Wikipedia's helpful ["Orders of magnitude" page](https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)), which shows us that: * This is just under a kiloton nuke. * This is bit over a [Massive Ordnance Air Blast Bomb](https://en.wikipedia.org/wiki/Massive_Ordnance_Air_Blast), the largest non nuclear bomb ever created. * This is a bit over the impact of an A380 at cruising speed - 560 tonnes at 511 knots Also remember this is just the energy that hit the wall - the breath also heated up the air, the ground, the dragon, and the poor people behind it. (Edit: Corrected a maths error, I had originally calculated this as over the strength of a Hiroshima bomb, it's actually about an order of magnitude below this.). [Answer] **No you can't** The breath is simply too hot. If it hits the umbrella and it holds, you'll still be exposed to incredible heat from all sides where the breath goes past you. It is able to liquify 4 inches of metal on an 80 feet surface! Assuming steel, that is 1510C or 2750F! But it's much, much hotter, as it can liquify 4 inches deep. In. A. Breath. The flash heating will probably cook you alive. Where it hits the ground or surroundings it'll likely liquify the material, likely giving off lots of toxic funes that'll rob you from breath or poison you, likely both. This will also add to the heat flying around you. The umbrella might not protect you fully as well, making you in even more dire straights. [Answer] **Frame Challenge: The premise of the original thread is wrong** The original theory is as follows: > > A pure iron wall has 30 HP per inch of thickness and Hardness 10. A Great Wyrm Red has a breath weapon that does 24d10 Fire Damage in a 70 ft. cone. Maximum damage is 240, which is halved against objects for 120, which is then dropped by 10 because of Hardness. So it's technically a little less than 4 inches thick that can be liquified. A 70 ft. cone has a maximum straight horizontal line in it of something like 80 ft., and everything in the AOE takes full damage. > > > Which someone disputed as > > 4 inch thick Iron has 120HP and hardness 10, and a Great wyrm breath weapon does 24d10 damage in a 70' cone which averages at 132 damage. > > > > > However fire would do half damage to objects (I personally wouldn't say that iron walls are particularly vulnerable to fire) which after hardness would be 56 damage so a basic MM great wyrm red dragon would probably heat the metal thoroughly but not completely destroy it. > > > I would go with the second method with averaged damage (as commonly you don't roll and use the average in a lot of DnD situations for sake of speed) in which case it would heat the metal but not destroy it meaning the breath is much less than expected heat wise. ~600 C is a lot less destructive than the initial 1243 C. However what is commonly stated in the RPG stack is *DND is not a physics simulator* thus, we can also assume that these measurements were not really thought out in terms of physics in general. [Answer] Make the umbrella with something akin to the [Shuttle thermal protection system](https://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system) > > The black HRSI tiles provided protection against temperatures up to 1,260 °C. [...] These tiles were such poor heat conductors that one could hold one by the edges while it was still red hot. [...] The HRSI tile was composed of high purity silica fibers. Ninety percent of the volume of the tile was empty space, giving it a very low density (140 kg/m3) > > > For comparison water has a density of 1000 kg/m3. Just be sure that the deflected breathe doesn't bounce back on some other nearby surface. I can't find information on their price per square meter, but from the answer to [this question](https://space.stackexchange.com/q/6577) I infer it is not prohibitively high, if jewelers can use it as soldering base. [Answer] What if the umbrella were made from the esophaguses of a Great Wyrm Red Dragon? The umbrella might well survive and be found smoking, deep in the wall's crater directly behind where the player -used- to be. [Answer] ## The Wall Would Explode Before it Melts You can not "melt" the wall in any thematically satisfying and meaningful since of the word. [Ash's energy calculations](https://worldbuilding.stackexchange.com/a/185985/57832) do a good job of expressing how much thermal energy it would take to melt the wall, but they do not tell the whole story. **Here are a few practical points that it misses:** 1. He is off by a few order of magnitude when converting J to Kilotons. By his calculations, it would be a 0.007762kT blast, or roughly the energy force of a really big conventional explosive missile. 2. High energy fires condensed into a small area create explosive forces that blast the steel away as you "melt" it. Basically you are doing this to the wall, but at about 1,000,000:1 scale. This means there are forces at play which may not require you to fully melt the metal to remove it. [![enter image description here](https://i.stack.imgur.com/CyOq8.png)](https://i.stack.imgur.com/CyOq8.png) 3. When shooting fire across a room, you create more heat than is absorbed by the target. With these 3 factors added together it is REALLY hard to say how accurate a simple thermodynamics equation will be; so, instead I will assume that a dragon's breath would probably have a similar thermal efficiency to an Oxyacetylene torch, then we can do some calculations to figure out how much energy is actually going into the metal. It was surprisingly hard to find the energy efficiency of an Oxyacetylene torch, but after running through a long rabbit hole of various sources I've found that: * Oxyacetylene torches produce ~1585.26 kJ/cuft of fuel * You can cut a 1/4" channel through about 10.9 ft of 1/2" thick steel per cuft of fuel * This means you need about 1163.49 kJ/cuin of steel to heat/blast your way through the wall. * Using a 90" tall wall you have a total volume of @ 345,600 cu inches to remove. * This requires a total energy of ~402,103,380kJ. Compared to Ash's equations, this means you are actually outputting about 12.38 times as much energy as it takes to just melt the steel to do so by heat blasting it. While this is still no nuclear bomb, it is roughly equivalent to blasting the wall with 10,544 liters of burning jet fuel. That is 17.6 liters per sqft. So, to answer your question, with a normal umbrella having an 8-10sqft surface area, standing in the dragon's spray means you getting pelted with the equivalent of ~140-180 liters of high velocity jet fuel. Even if the Dragon's breath failed to ignite, it would probably buckle your umbrella under the sheer force of getting hit by whatever fuel it it breathing at you. If your umbrella were able to take the force of getting hit by the dragon's breath, you would then have to be able to survive the explosive force of that much fuel combustion in such a small place. Even if you could survive that, you are then looking at a sudden wave of heat that is going to be hotter than the surface of the sun coming at you from all angles. The only way I see your hero surviving this is if he is wearing and entire suit made out of [starlite](https://en.wikipedia.org/wiki/Starlite) or similar material. Starlite can protect a person from 5 minutes of sustained blow torch heat; so, it can probably protect you from the heat of a dragon's breath as long as you can solve for how to make it durable enough not to crack under the explosive force... also you're hero will need to be super human tough to survive the explosive forces being transferred through the armor. [Answer] **This very much depends on the mechanism of how the breath works.** If it's heating by radiation (i.e. some kind of heat ray), then @Ash's answer above gives a convincing 'No'. However, this kind of answer also prevents the dragon surviving the breath, so we should probably conclude this is not what the rules intended. **It may be better to assume it's more like a flamethrower**. Flamethrowers work by squirting out a flammable substance, which is ignited. Thus the heat is generated not at a point, but across the target area, and not instantly, but over a period of time as it burns. Obviously a *very hot* flamethrower, something like thermite perhaps. **Would this work?** Thermite has an energy density of 20Mj/L Let's consider a 10cm square of 4" thick wall. Let's for convenince, metricise this to a 10cm cube of iron. this weighs 7.8kg. Irons specific heat capacity is 444 J/kgC, and we need to raise it 1523C 444 \* 7.8 \* 1523 = 5.2MJ. So a 2.5cm thick layer of thermite could melt through 10cm iron (assuming all the heat goes into the iron). Let's say 50% goes in, and we need a 5cm layer. So (handwaving away how the dragon stores and fires large quantities of thermite), the breath weapon could be thermite-based. **Can an umbrella deflect this?** A standard umbrella can easily deflect thermite before it is ignited. It's not impossible for an umbrella to deflect lit thermite, though obviously it'll need to be thicker and heat resistant – it doesn't have to withstand the heat indefinitely, just long enough for the thermite to be deflected. Some kind of fibreglass cloth is likely? If this leaves you standing in a small clear patch in a large field of thermite, your life expectancy won't be great. But if this protects you from a stream of thermite which otherwise splashes down some distance away, then there's no reason you can't survive. [Answer] **Supposing your umbrella forces an air current in front of it to shield the user.** If your handle is hollow and pushes the cold air behind you up and out around the outside of the umbrella, one could hope the forced convection will reduce heat transfer sufficiently. Basically, we're making an air curtain in front of the umbrella. This requires a little bit of machinery or magic inside the umbrella but it seems you have no other choice if this is to work. Convection formula: P = dQ/dt = h \* A \* (T − T0) Therefore E = h \* A \* (T − T0) \* Δt A human can withstand temperatures of 42°C and the breath is at 1246°C meaning T - T0 ≈ -1200°C. Let's suppose the Wyrm's breath lasts Δt = 45s. Its a big thing and a long human breath is about 15s (I timed myself). A = 2.5 m^2 Taking into account the calculations made by others on this thread, we have an E = 30 GJ energy transfer. And yeah, there is latent heat of fusion and dissipated energy but a few numbers were taken for worst case scenarios and constraints have been eased since so this is a good order of magnitude. BUT this energy is spread over a 70-ft = 21.3 m cone according to <https://www.d20pfsrd.com/bestiary/monster-listings/dragons/dragon/chromatic-red/red-dragon-great-wyrm/> So we are only taking 100 \* 2.5 / 21.3^2\*pi = 0.175 percent of that because the rest is not directed towards us. We get a final E = 0.00175 \* 30 GJ ≈ 50 MJ. For air on air conducto-convection, we have empirically h = 10.45 − v + 10√v according to <https://physics.info/convection/> This gives us v - 10√v = 10.45 - E / (A \* (T − T0) \* Δt) = 10.45 - 5\*10^7 / (2.5 \* -1200 \* 45) ≈ 380 m/s So √v = (10 + √(100 + 4\*380))/2 ≈ 25 √(m/s) therefore v ≈ **625 m/s**. That's a bit under twice the speed of sound in air. I don't know how permissive your magic/machinery system is but it's *theoretically possible*. Plus, you can probably modify many these numbers to make it more favourable, especially if the heavy constraints on total energetic output are eased only slightly (a slightly smaller wall means orders of magnitude less energy and therefore orders of magnitude less speed for the air curtain). For example, if you double the breath time, you almost halve the required speed of your air curtain. The physical model is not perfect but it works well enough to get an idea of the situation and gives a nice proof of concept. Hope this helps! ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 4 years ago. [Improve this question](/posts/161928/edit) There are a number of stories that contain a being that can turn parts of itself intangible at will, meaning it won't interact with most objects: * The twins from the second Matrix movie; * The demon from Kim Harrison's first Hollows book; * Kitty Pryde from X-Men. This seems to make physical defenses useless: a shield won't stop a being that can just make part of their arm go straight through the shield. A sword attempting to cut off a body part will just go straight through the body part without doing any damage. A wall or a door won't stop it either because it can just phase through. For this question, assume the following properties: 1. The attacker can make any or all parts of his body intangible at will, for any length of time. Intangibility means it does not interact with any baryonic matter, whether living or inanimate. The process that causes the intangibility is based on fictional science and is not of magical or supernatural nature. 2. The attacker can still "walk" on any surface that a tangible person would be able to walk on, as well as on the air. 3. The attacker can have an intangible bit in between two tangible bits. 4. The attacker can still eat, drink and breathe and has full sensory perception, even if the sensing body parts are intangible. 5. Anything the attacker wears or wields can also be turned intangible, following the same rules, as long as he touches it. So he can't fire a projectile through a solid wall, but he can shove his gun fully through the call, fire it and then retract it. 6. The setting is modern times to near future, with currently no power dampening tech available. How would one defend against such a being, be it through preparing the location where the confrontation will be or through specialized armaments and training? [Answer] "4. The attacker can still eat, drink and breathe and has full sensory perception, even if the sensing body parts are intangible." Assuming based on their other immunities that they would be unaffected by airborne agents while intangible. Assaults on the other senses should work. Flashbangs, Sonic attacks, Bright lights. Attacks on their fully perceptive sensory organs should yield deterrent and if enough energy is pumped into them this way could be a bit more than that by causing Blindness, Deafness or internal bleeding from ruptured organs such as eardrums. [Answer] # Raising the Cost of Interaction When such a being is intangible, it *can't* interact with anything in a useful/harmful way: it must make at least part of itself tangible to be able to cause harm. So, make the act of becoming tangible *extremely* costly and dangerous. ### Radiation: Strong ionizing radiation can cause immediate and invisible damage to living tissue in the area. Bathing an area in such radiation can cause severe damage to an intangible being the instant it decides to become tangible. Even if it only makes a part of itself tangible, it can sustain serious injuries before it even realizes that something is wrong. In this instance, a soldier would either need protective clothing (which could give away the threat), anti-radiation meds (much less effective than blocking the radiation altogether), or a death wish. Non-ionizing radiation (such as RF or microwave) can cause thermal effects: it can literally cook living tissue. While this can be more immediately noticeable than the damage caused by ionizing radiation, it can also be used as a directional weapon. Large, ground-based antennas used for communicating with satellites can emit this type of energy in a specific direction. # Nowhere to Hide: If the being's control over its power is too great to rely on it ever becoming tangible, then you must strike at it while it's intangible. ### Carbon Monoxide: Invisibly deadly, an entire facility could be filled with CO without the target ever realizing it. Even though they're still able to breathe while intangible, they need something *to* breathe. If all that's available is CO, then they'll be dead before they've taken a dozen steps towards their destination. Soldiers within the effected area could theoretically be given implants which allow them to survive within the CO for a short while (essentially, air supplies which can be hidden under clothing, and connect to the user's airways in a way that's not obvious). This is science fiction, but could reasonably be created with technology not much more advanced than what currently exists. Alternatively, soldiers could be armed with weapons that emit CO (like a spear that pumps car exhaust out of holes along its haft). If these weapons are stabbed into the lungs of the intangible being, they'd instantly displace the atmosphere in that immediate vicinity with carbon monoxide, causing injuries right away. ### Explosive Decompression: If the being needs air, then they'd theoretically need that air to exist within a specific pressure range, like a regular human would. That being the case, rapidly exposing them to negative pressure would be immediately and violently injurious. Sticking them in a vacuum chamber probably wouldn't work quickly enough to prevent escape, but a thermobaric bomb could likely do the trick as long as you don't mind all the collateral damage. [Answer] Radar-linked auto-guns. The radar lets you know which parts of him are tangible and the guns perforate those parts with bullets. This does require some kind of visual identification unless the entire area is a kill zone. Or simply program the gun to auto target any one who starts having pieces going intangible. [Answer] ## Through the power of science!!! You said "The process that causes the intangibility is based on fictional science and is not of magical or supernatural nature." If this is true, then that means this phasing is a physical process of some sort, one that a human body is able to generate and maintain. Since this process is not magical or supernatural in nature, then it must be some natural (non-magical, not supernatural) process that can probably be replicated. Since it is (presumably) a human body producing and sustaining this process, then it must not require a tremendous amount of energy to sustain. So since this is (probably) a physical process, it is very likely that we could find a way to observe it - specifically the method behind it - beyond simply saying that it's phased now and it wasn't before. And since this process is able to be generated and then sustained by the energy within a human body, it is well within our means power this process with technology rather than biology, if we can just learn how the process works! Assuming that this power is not unique, that you are able to find someone with this ability who is willing to cooperate, and that you have sufficient funds for this, it would be easy (I'd go as far as to say trivial) to find a physicist or other notable researcher willing to study this ability. It would be even *more* trivial to then script this scientist or research team (you do get to decide this, after all) to make a breakthrough (they're *brilliant!*) and gain a significant understanding of this process! And at that point, you now have both an understanding of the process, and sufficient power to recreate it! All you need then is a little more research and a little bit of hand-waving (no need to *actually* explain the process), and now you can reproduce this effect yourself! ## But how does this let me defend myself? Well, if you have the understanding and the means to *power* this phenomenon, then it's not hard to imagine building something able to *disrupt* this phenomenon as well! After all, your researchers understand this process *very well* (they're rather enthusiastic about opening a new branch of science), and they've made a number of breakthroughs! For example, they now know not only how to replicate this process, but also how to *disrupt* this process! And once they know *how* to do it, it's only a matter of time before they *build* something that can do it! They're scientists after all, and one of the fundamental principles of science is verification! Admittedly, there's no guarantee that this process will be as easy to perform as the original phasing process we observed, so it could be particularly expensive to do so. Still, a little bit of handwaving and this process's resource consumption becomes at least manageable, if not insignificant. Now if you have the resources to fund the research into this, then you almost certainly have the resources to either patent this technology or otherwise acquire this technology somehow. Even if you don't have those resources (perhaps you are a competitor to the people who *did* fund this research), there are... *other* ways to acquire it. But regardless of how it's done, you *need* that technology if you want to keep yourself safe from people who can phase. And once you have that technology, all you have to do is deploy it in such a way to keep you and your assets safe from those... phasers?... who would otherwise do you harm! Generate an anti-phasing field around your home! Set up a "honeypot" safe in a sealed room as bait and trap the phaser when they try to break in! Build an anti-phaser into a gun, and briefly activate it whenever it fires a bullet! Doesn't matter! You now have the means to block, trap, and kill a phaser just like you could any other person! As for *how* this technology works, what its limitations are, and so on, that's whatever you want it to be. Have fun! [Answer] **This being is invisible and invincible.** Taking your first point at face value, this entity can choose to turn its whole body intangible, meaning it will not interact with any of the common types of matter we find here on earth. As long as it remains intangible, it cannot be affected by any kind of wall, gas, or projectile. Because it can turn other objects tangible/intangible at will, there really isn't any reason for the being to turn its own body tangible and make itself vulnerable - it can just wear a pair of gloves which it turns tangible whenever it needs to interact with a physical object. The being is completely safe so long as it remains intangible, and it has no compelling reason to ever become tangible. There is nothing you can do to stop it. [Answer] Two words for you: *nerve gas*. Best way to prepare an area you're anticipating them entering. By way of a bonus, you can seal it up nicely to reduce the risk to people outside. Initial exposure to a fatal level of neurotoxin can be unnoticable. Even if they just phase a hand in, it can seep through the skin, if you choose the right nerve agents. By the time they realise their terrible mistake, it will be much, much too late for them. [Answer] Considering it can do whatever it wants, whenever it wants, and is not affected by anything it doesn't want to be affected by, there are 2 options: 1.Something very special (and probably unknown) - like cryptonite for Superman, or: 2. Distance. Distance would be your only defense. You mention that it can "walk", however if we imagine this being having powers similar to those of the Matrix, but a bit better (they seemed to be able to only activate only when their whole body is in the clear, while in your case different parts can operate separately as needed). This puts the following question: If the being is in it's invincible mode and no part of it's body interacts with anything, is it still affected by gravity? If yes, then gravity would be one of the options, if no, then that should somehow cover the distance part, considering it is not affected by Earth's gravity, and the Earth is moving through space at huge speed, all you would need to do if somehow force it in it's invincible state for a somewhat prolongued period of time (technically a few seconds would be needed). [Answer] Assuming 1) the attacked anticipates the attack and has information about the abilities of the attacker 2) the intangible person is still visible and 3) breathes normal air: I would video-survey the area, being careful not to have walls/floors thick enough to hide within. When I detect the attacker, I simply flood the access routes with gas. I assume the attacker turns tangible when unconscious? If not, do they fall through the floor? If not, well, it might be safer to simply kill them. [Answer] **Turn off the light** If he can see you he can't attack you. Sometime running is the best outcome, for your next encounter be sure to be the one coming from the shadow. I guess even this godlike being must eat or fall asleep. SmokeBomb, flashlight, illusion, send him inside a portal to an unknown and unpleasant location. **Velocity** Make him jump off a train, he will keep the same speed as the previous frame (the train). If he doesn't materialize again he will never stop, cause no force is slowing him down. When it does, he will likely sever extreme damages. [Answer] This is in fact a solved problem in the Warhammer 40k universe. [Necron Wraiths](https://wh40k.lexicanum.com/wiki/Wraith) perform almost exactly this kind of behaviour in combat to allow their weapons to bypass body-armour and even the victim's skin so they can strike at internal organs. They have essentially two phasing behaviours. They can phase-attack, where their weapons pass through body-armour and even the skin of their enemy without harm but slash at internal organs and components (of machinery) They can also use their phasing to defend themselves by completely becoming intangible. The phasing is very rapid, so they can use it to allow bullets and projectiles to pass through them They do not have the ability to attack while fully phased, so they have to "decloak" to attack, which renders them vulnerable. Generally it's not a problem because they decloak while lunging for the attack. Defending against them essentially entails sticking a solid object in their path while they lunge, so when they decloak they impale themselves on it, or are forced to retreat or recloak, stopping their strike. Alternately, timing your attack to when they're lunging is effective too. For bonus similarities, Wraiths can fly and see through walls and in complete darkness... [Answer] ### Create a situation where he has to be both tangible and fully intangible Like avoiding danger while staying on a platform. *(Please feel free to correct my grammar and prepositions without asking)* For example, attract the attacker on a ladder above lava (or anything else lethal), then trigger an explosion on him. He will have to turn fully intangible to avoid the explosion, but he can't do that while staying on the ladder. He'll fall through into the lava. Your rules doesn't say what happens if he falls into lava while being intangible but I don't really see how he could get out alive. And you might not even need lava. Consequently: **Making him fall inside the ground**. Falling from a high point might be lethal in all cases, depending on your rules. When he reaches the ground at terminal velocity(\*), if he's tangible he'll die instantly, and if he's intangible he'll fall *inside* the earth (and will keep falling until he decides what to do!). Then what happens, based on your rules, **if he's inside matter and he tries to become tangible?** Maybe he just can't, if so he'd keep falling towards the the center of the earth (eventually reaching the other side), but there's no way he can breathe so he'll suffocate in no time. Maybe if he does he dies instantly (or just lose a body part, if it's just a arm in a wall for example). Either way he's dead. Ultimately it's your choice, but if you want to give the attacker a weak point it's a great choice, it makes sense. Also, based on the fact that he can "walk" on any surface a normal human can, there's a choice you have to make. I see two possibilities: either he always keeps the sole of his feet tangible, or the ground magically repulses him. If it's the latter, he'd reasonably crush on the ground even when intangible, so I think the former makes more sense. But if he's falling really fast, making a small part of his body tangible won't save him. --- (\*) As a bonus, if he stays intangible while he falls he'll never reach terminal velocity because the air won't slow him down, so he'll keep gaining speed indefinitely :) [Answer] > > The attacker can still eat, drink and breathe and has full sensory perception, even if the sensing body parts are intangible. > > > **Lasers** If your creature can still see, then they can have their eyes damaged by intense light and if their intangible body parts can be affected by light then that means they are constantly vulnerable to lasers. You might say "Lasers don't cause that much damage" but dying "by a thousand cuts" may be enough to deter any attacker long enough to escape. [Answer] ## Sniper rifle. Or basically any gun from an ambush. Let's assume they don't have supernaturally fast reflexes. (If they had, it would be a superpower on its own). Also we assume these beings don't spend all their down time phased. Most bullets fly faster than sound, so if the shot is fired from outside the target's field of vision, then the bullet will hit before the sound of the gun can be heard. Even if phasing out is an instantaneous action and it doesn't require any preparation or concentration, and the target starts phasing as soon as the bullet is felt, the fastest human reaction time is around 0.12 seconds (most healthy humans average at about 0.25 and it's insanely hard to reduce it below 0.20 even with training) During that time a rifle caliber bullet (with a muzzle velocity of 850 m/s) can travel about 100 meters, more than 300 feet. This means that even if the intangible being can instantaneously become intangible as soon as he feels the bullet hitting, and even if he has reaction times a thousand times faster then the fastest human, the bullet already splattered his brain before he can turn himself intangible. ]
[Question] [ My aliens want to build the heaviest chemical rocket possible: They never were much into space travel, since their planets' gravity is about 1.5 of ours. They made lots of bad experiences fighting against gravity and 'decided' to keep their technology on the ground. Suddenly the world's biggest corporation decides that it's absolutely necessary and very urgent to send a few drives, a breeding station, and some robots into space. They don't care about everything they've built up or the rest of the world. They go with chemical engines because they don't have any experience with stronger ones. That would be about 100 tons of rocket for 1 gram of payload? Can we also use nanotubes and diamonds to make it hold together? Nice. The best place for launch is the planets largest mountain, letting you skip a part of the atmosphere and also letting you abuse some of the planets rotation. Still, there's a good amount of distance to cover, because the atmosphere goes about 2 times further than earths. (50% hydrogen, 40% nitrogen and some heavy stuff that doesn't matter) If the air was warmer, it would be easier to pierce through, right? What could be better suited to warm up the atmosphere than a bunch of bombs? They'd shoot up a few rings of nuclear warheads that detonate at various heights, wait until pressure and wind are ok, uncover the rocket and launch it. *Of course air density is one of the less important factors when thinking about launching a rocket. I want it to be important, because I want to nuke the sky. I also know that there are better ways to escape a planets gravity than chemical engines, but that's what we're working with here. Try to work with a lunatic, please.* Two questions: Is this way of heating up the atmosphere realistic? If not, what would be the best way? [my last post with a similar topic](https://worldbuilding.stackexchange.com/questions/158406/whats-the-limit-of-my-rockets-weight/158421#158421) I'd also be thankful for comments that mention more variables to think about. What else would the aliens have to do to launch their monster of a rocket? It's not about solving a problem, but about creating new ones which the aliens can barely solve. [Answer] **Mount your nuke on the pointed spike on your rocket.** Heat reduces drag. If you are going to make heat, make it where you need it - right in front of your rocket. This works to reduce air resistance. <https://www.researchgate.net/publication/268555192_Drag_Reduction_of_Spiked_Missile_by_Heat_Addition> > > Experiments conducted in Germany 45 years ago and later repeated in > the USA in the early 1980s indicate a drag reduction of approximately > 50% for a spiked missile due to burning of hydrogen gas in the > separated flow. This paper investigates through computational fluid > dynamics (CFD) means the role of heat addition, by burning of hydrogen > gas, in reducing drag... Addition of heat into the turbulent > separated flow virtually eliminates the shear layer reattachment shock > wave and also modifies base drag. Injection of hydrogen into the > separated flow region without burning did not eliminate the > reattachment shock wave, indicating that heat addition is a necessary > condition for eliminating shear layer reattachment shock wave and drag > reduction, as observed in both the German and the USA experiments. > > > If you have the fixings for a nuclear bomb you can probably make a fission reactor. Mount one on the tip of your rocket and use it to heat the tip to very hot. From the linked article - the longer the spike the better this works and so your rocket should have a very long glowing hot spike on the tip. [Aerospikes](https://en.wikipedia.org/wiki/Drag-reducing_aerospike) are already in use but I could not find a picture of a glowing hot one. Once you are out of the atmosphere you might want to dump the fission reactor. As there is less passing air it will not be cooled as well and it will get hotter and hotter. - Note - the large percentage of hydrogen in your atmosphere will also reduce air resistance as compared to Earth. Also people might talk in squeaky voices. [Answer] The main issue with this approach is that it's a *largely pointless* way of affecting the rocket power, as atmospheric drag is a very small part of the energy cost of launching a rocket. A much greater burden - especially on a high-g planet - is [gravity drag](https://en.wikipedia.org/wiki/Gravity_drag): broadly speaking, the energy you have to expend maintaining the height you've already gained while you work to go higher/faster. As ever, the rocket equation is not your friend here. The best approach is definitely to gain as much height and speed (remembering that gaining 'sideways' speed is what rockets spend most of their energy doing) *before* beginning the rocket phase. Putting the launch site on top of a mountain is a good start, but you need to do more. An intelligent race on a high-g world would certainly have discovered both lighter-than- and heavier-than-air flight, and the idea of rocket-propelled flight won't be any more novel to them than the idea of rocket-propelled rocketry. From your mountain-top launch site, you should lift your launch platform as high as possible into the atmosphere using a balloon. Since the atmosphere is already 40% hydrogen this will consist of filling a zeppelin with pure hydrogen *and **then** heating it like a hot air balloon* - what could possibly go wrong?! This is a much less disruptive way of getting through the bulk of the dense atmosphere. Once up there, you should launch your rocket more like a glider than anything else, using wings to generate as much aerodynamic lift as possible for as long as possible. Since the speed of sound in hydrogen is much higher than in terrestrial air you'll be able to get a lot of lateral speed up in this mode before it becomes more practical to jettison the wings (or lift up out of the atmosphere) rather than continue to strengthen them. Your chemical rockets can then switch into pure rocketry mode, with a good headstart in both altitude and lateral speed. Meanwhile, all that uranium can be put to good use powering the heaters that will keep that mountain-sized zeppelin launch pad aloft. [Answer] > > Is this way of heating up the atmosphere realistic? > > > It'll heat up the atmosphere fine, but the low-pressure, low-density region left behind won't persist for very long. Certainly not long enough to fire a rocket through it. Or at least, not a rocket that needed to survive. > > If not, what would be the best way? > > > The best way is *not to use a chemical rocket*. I'm not sure that you'd have much luck even if you built some kind of evacuated launch tube, [Star Tram](https://en.wikipedia.org/wiki/StarTram) style, and shot your rocket out of that. If you're so willing to nuke your world, why not just implement [Project Orion](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)) instead? Lots of thrust, high Isp, everyone's happy. Apart from those who develop cancer as a result of the launches. It'll be easier than the launch tube, and it is more likely to work given your apparent tech level, too. [Answer] # Just use the nukes as propellant instead. Back in the 1960s, some NASA scientists investigated the possibility of spacecraft propelled by relatively small nuclear bombs; they called it "Project Orion". The idea is that the spacecraft would launch the nuclear bombs out of a hole on the bottom of the ship, where they would detonate; the bombs would be designed to be "shaped charge" explosives so that most of the bomb's energy would be focused back up towards the spacecraft, where it would hit a 20m steel plate. That plate would be connected to a massive set of shock absorbers, which in turn would be connected to the rest of the spacecraft. The numbers they calculated for it would be that such a rocket would be capable of carrying 6000 tons of cargo (the weight of an entire Saturn 5 rocket) to the moon and back on one tank of fuel. While I'm not a rocket scientist, so I'm not certain how much delta-V a rocket would have left when launching from your alien planet, I'm sure that they'd be able to do so. Unfortunately, international politics and Cold War tensions rendered the construction of nuclear pulse propulsion rockets infeasible, but this might not be the case for your aliens. [Answer] # What about lightning? Note: all the other answers about air resistance being totally negligible part of the rocket launch are 100% correct. But since this isn't tagged hard science, the rule of cool prevails. Nukes are inefficient at rarefying a column of air, because much of their heat is spread over a an area much larger than your rocket. Lightning however does very good at heating a very localized column extending from ground to the cloud layer. Lightning "bolts" naturally follow a column of air ionized by the the strong static field built up in the clouds. Another way to ionize the air is with a high intensity laser. So, mount an array of high-power lasers around your launchpad, wait for a stormy, overcast day, fire off the whole laser array at once, and take off as soon as the turbulence from the awesome giant column of lightning has dissipated. If you really wanted to stick with the "nuke the skies" concept, nukes definitely ionize the air pretty well, too. Rather than big clusters of megaton strategic nukes, you'd want a small vertical string of kiloton tactical nukes. You could combine that with the lasers to get could column containment. So a slow-motion video capture of your launch would show 1) A sequence of small nuclear blasts starting 2) Immediately followed by high powered lasers stabbing up into the sky 3) Immediately followed by a huge lightning blast 4) Followed a short time later by your scorched and wind-buffeted rocket lurching into the sky ## Bonus: In addition to the chemical rockets, harvest the lightning strike to give your craft some initial kick with a rail-gun type launcher. [Answer] A few years ago I looked at a proposal to speed aircraft by using a laser to ionise the air in front of them. This is an extreme form of plasma aerodynamics, which is mainly being tested with gentler approaches, but it would have the effect you desire. The trick is using an ultra-short pulse laser which is essentially self-focusing to achieve the required intensity with a relatively modest laser. ]
[Question] [ This was an idea loosely inspired by a Sci-fi movie that I will not name here. But the relevant part is that it involves an interstellar colony ship landing on a planet and the crew learning that the ship had been *submerged in an ocean.* Now there is something that kind of bugged me at the time of seeing it, that I thought would be a rather interesting set piece that I myself would like to work with. To illustrate this, here is a rough cross-section of a spin gravity spaceship in space. [![enter image description here](https://i.stack.imgur.com/oHITy.png)](https://i.stack.imgur.com/oHITy.png) Now, this set up works because the only gravity is generated by the spin of the ship. Up and down are meaningless terms in space but the passengers need some way to orient themselves, so down is always towards the floor and outside the ship while up is always towards the center of the ship. Now here is the cross-section of the ship when it is submerged. [![enter image description here](https://i.stack.imgur.com/sh7UY.png)](https://i.stack.imgur.com/sh7UY.png) This changes things because now there is a definite down that no longer corresponds to the floor. The bottom of the ship would be unaffected the top of the ship would be completely upside-down while the sides would be...well on their sides. Where once there was a gently sloping hallway now it’s a really long curved shaft going up and an equally deep pit going down. Which personally I find much more interesting topography than what we got in the film where the deck plan was always nice and flat. Poseidon adventure on steroids. But this new orientation of the ship creates a rather interesting problem that I admittedly can’t think through. How on (insert planet name or designation here) can you get around? So here is the riddle: **How can human adventurers navigate and maneuver around a submerged spin gravity ship to salvage from it?** **Edit:** I have decided to pivot the original hard science tag with the more accurate science-based tag which doesn't require the strenuous citations. As was pointed out this question is harder to come up with hard science answer to, and I really don't want any of your wonderful comments to be deleted because you didn't include equations that I can't make head nor tail of. Thank you for enjoying this post. [Answer] Need some dimensions to work on this : [![enter image description here](https://i.stack.imgur.com/sh7UY.png)](https://i.stack.imgur.com/sh7UY.png) From the referenced show, which shall not be named: the crew, when they became aware of their situation, escaped in pods to the surface where they could see the coastline in the distance. According to this [article](https://researchmaniacs.com/QuestionsAnswers/HowFarCanTheHumanEyeSeeOnTheOcean.html), that puts the crew, at most, 2.65 miles away from the shore (of course, it's relying on Earthlike geometry). The characters are able to swim to land, which would cause me to believe they are much closer. Maybe 1 mile or less. [![enter image description here](https://i.stack.imgur.com/nK76s.png)](https://i.stack.imgur.com/nK76s.png) Again, relying on Earthlike geometry, the [continental shelf](https://en.wikipedia.org/wiki/Continental_shelf) is no more than about 100 meters deep. Assuming the spin was 1 whole g (9.8 $m \over {s^2}$) : $a = \omega^2 r, {\delta{a} \over {\delta{r}}} \approx 0 = \omega^2$. $9.8 = $So, what all that means is that I don't want some sort of strange blood-pooling effect because the "gravity" at your head is too much lower than the "gravity" at your feet. A ship diameter of 100 meters (50 meters radius) would spin at 0.442 ${radians} \over {sec}$, and ${\delta{a} \over {\delta{r}}}$ for a ship this size is about 2% of "g". That seems low enough. So, I'd guess these dimensions : * Ship diameter : 100 m * Bottom depth : 100 m * Top depth : surface (light blue in the image); or just beneath surface at tide. **At the top:** Everything is upside down. You can stand on the roof and walk with some safety. The grade of the "roof" starts to increase as you approach the sides : You can refer to this image for grade, or here are some high points - * 20 degrees : 35% grade (difficult walking) - this grade kicks in at $+ \over -$ 20 meters from the highest point (so about 40% of the top and bottom can be walked) * 90 degrees : $\infty$ grade (vertical climb) (about 60% of the station). You'd need up to 60 meter long ropes to navigate to the bottom. Many typical climbing ropes are 100 meters or 200 meters long. Ropes will have to be secured to some fixture on the ship. It might also be possible to climb some distance from fixture-to-fixture. [![enter image description here](https://i.stack.imgur.com/q2mDc.png)](https://i.stack.imgur.com/q2mDc.png) Although the ship has open access to the air, some airtight seal is keeping water pressure out below the surface, or the flooded sections are sealed. In the later (and more likely) case of the flooded sections being sealed, no special diving equipment is required on the inside. Pressure on the bottom is roughly the same, in this case, as it is on the top. No special equipment would be required. It may be possible to reach flooded sections through airlocks that were meant for space, but can be used for this purpose. There also may be environmental seals between parts of the ship. \*\* At the bottom \*\* All moisture, dust, and dirt is working it's way to collect at the bottom, under the guidance of gravity. I'd expect the floors to at least be wet, unless an environmental control system is still working to remove humidity from the ship. As said above, if the flooded sections are sealed, the pressure down here is 1 atmosphere. The air may be stale, if oxygen scrubbers aren't still working. And you may need light, depending on the state of the power and lighting systems. As on the top, at the bottom, you get a nice $+ \over -$ 20 meters (40 meters total) of walkable surface. Which is about 40% of the ship. In this case, the floor is the floor and everything is "rightside up". [Answer] ## Climbing/Caving Equipment Humans have been maneuvering through tight, awkward, occasionally-vertical spaces for centuries, if not millennia. Climbing and caving gear is well-established and well-developed, and would work just as well in an artificial environment like you're describing as it would in a natural cave. For flooded portions of the interior, cave-diving is also a well-established discipline, so that also wouldn't be anything too novel. It's definitely a specialty, though, as it's one of the most dangerous types of diving. Outside the ship, normal scuba/submersible equipment could be used, just like any other underwater salvage work. [Answer] **DISMANTLE THE SHIP** First off, rule number one in space or on planets is never board a derelict ship. it's never safe. Even on the ocean, boarding derelict ships are unsafe. hundreds of shipbreakers in Alang India die every year inside these hulks due to workplace accidents involving these ships. Like a man looses his footing to an oil patch and falls all the way down from the top deck to the ship's keel. One time this happened, and a man broke his back. He was one of the lucky ones. But, with most ships, if it has been submerged for that long in water, it's beyond salvage, so as dangerous as it is, the best course of action is for the flightless hulk to become scrap. A floating crane would be what you'd want for this task. just cut apart the ship, and take it up piece by piece. [![enter image description here](https://i.stack.imgur.com/y0bue.jpg)](https://i.stack.imgur.com/y0bue.jpg) Because the ship being rendered into scrap will be less cost intensive than restoring it--which will in all likelihood never be possible. And the ship turning into scrap will proved much needed building material for starting the colony. [Answer] If the ship lands on a planet deliberately under human or computer control, instead of crashing, then landing should be a process the ship is designed for. In that cases, the ship would be designed so that nobody would be upside down when on the planet. Presumably the ship would stop rotating while still in outer space, so that it wouldn't have any gravity from spinning. Everyone would be in weightlessness during the landing, except for acceleration and deceleration and the planet's gravity getting stronger and stronger. So if the ship deliberately lands on a planet instead of crashing, it should be designed to stop spinning and descend without spinning. And presumably the crew quarters would be designed to turn so that the former down direction to the exterior of the ship, was now pointing d toward the planet. Thus after they landed on the planet the decks would be underneath instead of upside down or vertical. So the crew quarters would have to be in several parts that could separate and move to a new orientation and then reattach. Thus I suspect that the ship would land, if it landed deliberately, with its long axis pointed down at the planet's surface, and the crew quarters would be swung around at right angles from their previous orientation so that their decks now pointed down toward the planet, instead of pointing outward perpendicular to the long axis of the ship. [Answer] # Cut internal power and flood the ship. This is likely to be one of the safest ways you can actually explore the interior of the ship. It solves a number of potential issues, namely: * Gravity becomes mostly irrelevant because you can easily move in three dimensions. * You don't have to deal with the otherwise complicated process of entering and exiting the ship. * The equalized pressure inside and outside the ship will make it less likely that structural damage will cause it to crumple like an aluminum can. * Because of the uniform environment inside and outside, it becomes much easier to use drones and robots to do the exploration instead of actual people. The downsides are that for safety reasons, everything inside has to be unpowered (you're not *likely* to get shocked, but it could still happen), and the submerged environment brings some interesting engineering challenges (mostly due to pressure/temperature/salinity differentials screwing with buoyancy). Of course, some of this also depends on the design of the ship itself. If it was properly designed to allow easy traversal in zero gravity (that is, without the ring spinning), then regular climbing becomes much easier, but so does navigating underwater. OTOH, if it's a smooth design like the stuff seen in a lot of sci-fi (think like the inside of the Death Star in Star Wars, or the inside of the USS Enterprise in Star Trek), then the only practical option is going to be flooding the ship. [Answer] One seldom sees a rolling tire come to rest standing up. If the ship is being retrieved as salvage... and assuming it survived reentry (somehow), it seems its most likely final orientation would be lying on its side, more like a disc than a ferris wheel. In that case, none of the issues you mention would apply. If it somehow it DID land upright, I would think the easiest way to get around inside would be to simply knock it over first. If its frame could somehow survive reentry and the incredible water pressure toward the "deep end," it could surely survive being knocked over, too. [Answer] ## FLOAT the ship Especially if the ship is in an awkward position like shown (you say we’re looking endwise upon a cylinder like *Rama*, not a torus like the *2001* space station). The way you float a ship like this is by welding tanks to it, to the outside. You then selectively flood or evacuate those tanks to change the bouyancy of the entire structure. You saw this done with the *Costa Concordia* recovery, and it’s being done again (with an un-sunken ship) with the *Texas* restoration. In Texas’ case, they want permanent bouyancy, so they are filling those voids with foam. But you would certainly want to have them under control **so you could rotate the ship**. In fact, you would attach the first few tanks, some underwater (filled with water) and then fill them with air to lift the ship off the bottom *and* rotate it for attaching more tanks. ## Get it away from the shore! The biggest threat to the ship, sitting on the bottom and exposed to air, is that sea and wind forces will move it back and forth repeatedly. It happens at least once a decade that a US destroyer or other Navy ship finds itself aground, and is torn apart by sea forces dragging it across the bottom, before the Navy can respond. In fact, it’s all the Navy can do to get the fuel drained (to prevent an oil spill). The ship is a total write-off. Now, if the ship is deeply embedded so it can carry the sea loads, this may not be a problem. But it will become critical to move the ship from “solidly not floating” to “solidly floating” in one calm day, much like the *Costa Concordia* lift. ## And then get it into a deep, *calm* harbor Once you can get it independently floating, you will get it away from shore and float it in deeper water. (But not so deep as to be unrecoverable if it sinks). Meanwhile, you’ll be preparing a deep harbor capable of taking it. Because you’ll want to be able to effectively “dry-dock” it. That probably means using a natural deep harbor like San Francisco Bay and dredging out parts of it so it can be moved farther from sea action. [Answer] Handwaving all the factors that allow the ship to survive being sunk in the ocean, there's a really simple answer: you build a salvage vessel capable of raising the spaceship. This has actually been done, semi-successfully. In the mid-70s, the US CIA funded the construction of just such a ship, the Hughes Glomar Explorer, in order to recover a sunken Soviet nuclear submarine: <https://en.wikipedia.org/wiki/Project_Azorian> [Answer] # Ship is sealed below the water line, buoyant, and you want to salvage every gram? Go to the section above water, take every intact peice of equipment, then cut the ship just above the water line. Remove that peice and process the metal. The ship is now lighter as its mass is lower, and will rise in the water. Allowing another section to be processed. [![Cut the ship and lift it up](https://i.stack.imgur.com/y4IR0.png)](https://i.stack.imgur.com/y4IR0.png) # Ship has inertial dampeners still intact? Recovery team goes in with a generator, powers up the inertial dampeners, and tweaks them to maximum dampening (minimal mass). Lower mass and higher volume will make the ship float very high in the water. That ring shape will rise, and flop onto its side. Gravity will still be the wrong way, but there wont be any long drops. # No flooding, and you need to salvage only a few key items? Rock climbing equipment. Drills, ropes, pulleys. Team of people belaying each other down the curved shafts bulkhead to bulkhead. # Flooding, and you need to salvage only a few key things? Scuba gear. Underwater lights. Rope to find your way back. If it's partially flooded, a mix of scuba and rockclimbing gear. # The entire ship is worth salvaging with aims to repair and re-use? The technique used to recover a sunken space ship is the same as used to recover a sunken water ship - use buoyancy to lift it. Lifting the entire ship can be done using compressed air and parachutes: [![Lifting a 6tn block of concrete from the ocean floor](https://i.stack.imgur.com/SLrer.jpg)](https://i.stack.imgur.com/SLrer.jpg) # The ship is a radioactivity hazard? If the reactor has melted down, and the ship is resting on the ocean floor, the ocean is keeping the radioactivity contained (every 7cm of water stops 50% of the radioactivity). You can't lift the ship. You can't walk through it. You can't cut it above water as that may raise the reactor above the waterline. Get a pressurised diving bell for divers to live in during the process (so they dont need to decompress between shifts), and salvage the ship bottom up. Cut parts of the ship, let the ship sink further, and lift bits up when they've been confirmed to be safe. That's slower and more expensive, but contains the radioactivity. [Answer] Spaceships might be big and strong but you're forgetting one thing. A spaceship is built for space. In space the pressure exerted on the Hull of a spaceship would be a problem the ship was designed to handle. This same spaceship will most likely be full of air or another mix of gasses suitable to the users of the ship. But that same ship underwater will not have a Hull capable to handle the immense pressures that the ocean brings down on it. Here on Earth those same pressures demand a special sub to get into the Mariana trench (and they're not very big) . So either the ship will be incredibly strong (a fancy super material) to resist the immense pressure that is exerted by the water. Or it will be a collapsed semi-imploded graveyard of the crew that went down with it. ]
[Question] [ It's war on other planets! A century old feud devolved into full scale interstellar war as the Federal Fleet goes on the offensive for the first time in its history. In an attempt to end the war swiftly, Federal Strategic Fleet Command devised a daring plan, a plan that hinges on the success of military operations on the surface. With the battle still raging in space, battleships move into position to land their troops on the planet below, and stand by to deliver orbital artillery support.... --- There are two problems here packed in one inconvenient package. The first problem is to locate targets on the surface. The second problem is to locate the ship relative to the surface. You might be thinking GPS, which would make things trivial. However, this scenario can happen on a planet with a GPS system controlled by the enemy, or no GPS at all, which is effectively the same thing. You cannot rely on infrastructures the planet may or may not already have, and that you may or more likely may not get access to. So the question is: ***How can you accurately and reliably hit targets with orbital artillery without using GPS?*** I was thinking triangulation using the ships, however they aren't really built to be GPS satellites. I'm not quite sure what you need for an accurate geolocation besides a good clock. Also there's the fact that the ship themselves don't really know where they are themselves, which may or may not be a problem. You can use anything you can bring with your own spaceships, preferably something that doesn't need to be deployed (like satellites) since those can be shot down. Troops on the ground can use any sort of beacon to designate targets, though the beacon has to be man-portable (and also woman-portable), and preferably launchable through a 40mm grenade launcher. We are talking about *precision* strike, give or take a couple meters. Targets are not mobile. The goal we strive for is zero collateral damage. I should also specify, the artillery we are talking about launches dumb (i.e. not smart, i.e. not guided) projectiles. It launches them really really fast, like 0.1% of c fast. They are also stupidly light to limit kinetic energy at non-WMD levels. [Answer] You don't need GPS if you can detect the target from orbit via radar or using high quality optics. Once you select your target your computers will calculate what you need to do to hit it. The calculations are pretty standard, you convert from spacecraft reference frame coordinate system to [ECEF](https://en.wikipedia.org/wiki/ECEF) coordinate system taking into account the pointing angle. That requires line of sight but if you position a handful of ships in GSO you can pretty much cover the whole planet. I don't know why you put restriction on smart/guided ammunition.[They've been around for a while.](https://en.wikipedia.org/wiki/Precision-guided_munition#Laser-guided_weapons), there is no good reason for space going civilization not to have them. [Answer] There are some very deeply rooted, age-old issues behind your question. In a nutshell they all boil down to: How do interstellar travelers navigate among the stars? Let's take a look at this question in depth, and then we can see about answering your specific question. **Terrestrial Navigation** So how do people on EARTH navigate, anyway? Well, thanks to generations of people who were either very bored or very curious, humanity has a strong collective grasp of exactly where the Earth is located within the solar system, and exactly what we can expect the night sky (and day sky) to look like at any given time on any given day. This is key to navigation. Using a sextant and any one of a set of [Navigational Stars](https://en.wikipedia.org/wiki/List_of_selected_stars_for_navigation) (or the sun, moon, or planets) a navigator can determine his/her exact location on the surface of the Earth. The positions of satellites in orbit are monitored by tracking stations at fixed, known location all over the Earth whose positions are accurately determined using stellar navigation. The GPS would not be able to function without these tracking stations, since their positions would decay over time. The tracking stations are able to monitor and adjust the orbits of the GPS satellites, since the positions of the tracking stations never vary, but remember that their position could never have been determined without first using the stars to get a bearing. No matter how advanced the navigation technique, a map of the sky is needed to take bearings. Something to remember is that the mapping of the sky around the Earth has taken literally thousands of years. Methods have become more sophisticated and technology more advanced, but the core of knowledge was still gained through prolonged observation and experience. This is presumably something our intrepid interstellar explorers will *not* have. **Extraterrestrial Maps** Luckily, thanks to a nifty phenomenon called [Stellar Parallax](https://en.wikipedia.org/wiki/Stellar_parallax), we humans have managed to map the stars beyond our solar system to a startling degree of accuracy. Unfortunately, this method has a limited range. Presumably as science marches on we will produce more and more accurate maps and longer and longer ranges, but as it stands we can currently only take accurate parallax measurements to a distance of ~1600 ly. This might sound like a lot (and it really is pretty damn far) but the galaxy is a very vast place. Our maps cover about 0.07% of the Milky Way Galaxy. That's not terribly encouraging, but for now let's just focus on what we *do* have mapped. **Extraterrestrial Navigation** So let's say we have someone who is really bored, really rich, and really sick of people. They hop in star ship and blast off at FTL speeds (#magic) and makes it to [Polaris](https://en.wikipedia.org/wiki/Polaris), which is about 433 ly away. But what now? Our explorer is too far away from Sol to use accepted sky maps. Stars will be in different positions in the sky thanks to parallax, since our explorer is so far from home. Luckily, our star charts cover this area, and with a bit of extrapolation our explorer can predict what the sky will look like in the Polaris system just from our knowledge of where the stars lay with respect to the Sun. If the ship has a powerful enough telescope, our explorer can use his current navigational data to orient himself in Polaris and start mapping more distant stars using more parallax. This might take some time, but it will both increase the accuracy of current star map and sky map and extend the current star map past what is currently achievable from Earth. Next our explorer will want to start mapping the planet (I assume he found a planet upon which he wants to settle). In an empty vacuum it would be very tough to chart a planet's orbit, but our explorer has luckily already mapped out the sky using his extrapolated parallax data. Using these stars as a reference, our explorer can watch the planet(s) and sun(s) and moon(s) and get a pretty accurate picture of the system of orbits, including critical data like eccentricity, inclination, etc. Combining this new data with the sky map can produce an almanac of useable navigational points in the sky including stars, planets, moons, suns, and possibly other alien objects. It is imperative, however, that this process goes in this order. Trying to map the planetary orbits without first mapping the sky will result in failure. Now that we have an almanac of navigation points our explorer can navigate the star system to his heart's content. Tracking stations can be placed on the surface of the planet using stellar navigation similar to that used on Earth, only with an alien sky and alien navigation points. These tracking stations, being permanent references, can be used to further deploy more navigation equipment like GPS satellites or the like. Now our explorer can move on to another star system and repeat the process for as long as there is predictable parallax data from which to pull. **Orbital Bombardment** Now for the fun part: bombing stuff. In the best case scenario (for bombing, that is) the planet over which the war is being fought is populated, the sky map is well documented, tracking stations are in place, and orbit data is very accurate. In this case orbital strikes can be calculated down to the tens of centimeter (that is not an exaggeration; we can almost do that right now on Earth with missiles). This is, of course, utilizing every available resource from ground station data to GPS satellites to visual rangefinding. In less optimistic situations the battleships will likely have at least some combination of above resources from which to draw. This will limit accuracy somewhat, but if there is a sky map and available orbital data then strikes are possible no matter what. In the worst case scenario where a battlefleet must fight in an unmapped system there will be considerable difficulty even hitting the correct continent. Sky mapping and orbital analyses will be fairly critical for accurate strikes against ground targets. That being said, all of the above assumes the use of fairly modern navigational methods. It is entirely possible that as science marches on technology will allow for accurate machine vision enabled computers that can orient a ship in orbit without any sort of sky map. A sky map would still help, of course, but in a pinch such a computer might be able to put the hurt on a target even without in-depth star mapping and orbit analysis. High power telescopes and accurate laser weaponry would also need no navigational data to hit a target in visual range. Just point and shoot so to speak. Technology may also allow for very fast mapping of the sky and orbit analysis. Current methods would take months to accomplish this with any guarantee of accuracy, but delicate enough sensors could perhaps give accurate data in minutes or even seconds, making the entire process effectively instantaneous. **Final Thoughts** I would say that given any reliably effective method of travel between star systems, there will also be an equally effective method of navigation to ensure star ships can get from place to place. Mapping is also the first thing anyone will likely do upon entering a star system for the first time, so unless there is literally no time at all to get one's bearings, it will probably be simple enough to warp into a system (or whatever method of FTL you prefer), map out the sky and any planetary orbits, and then commence with the mission, whatever it is. If mapping is truly daunting, then I would personally sent unmanned mapping probes far ahead of my colonists and military forces to ensure some data is gathered and waiting if I enter an unknown system. I hope I've helped some. Good luck! [Answer] **When you have at least four battleships in orbit above you** (three when you got a very good clock)**, you have GPS.** To determine your position on the planet surface, you need * the exact positions of three objects in orbit (orbits are very deterministic, so you only need to know the exact [orbital elements](https://en.wikipedia.org/wiki/Orbital_elements) of a satellite to extrapolate its position at any point in time) * your distance to them. That allows you to triangulate your position. GPS determines the distance by having the GPS senders in orbit send their current time accurately to the nanosecond. The GPS receiver can then calculate the distance to the sender based on the time-lag due to the speed of light. A fourth GPS sender is required as a time reference, unless the GPS receiver also has a clock which is as accurate as that of the GPS senders. Present day GPS receivers do not have clocks which are accurate enough, but in a science fiction scenario where you have FTL travel, atomic clocks might be small enough to fit into a handheld device. That means you just need your ships in orbit to send their current position in orbit and their current time to the troops on the ground (normal GPS satellites do not send their position regularly. They don't need to because they maintain predictable orbits. But a ship in battle will likely maneuver a lot). Note that you must use some form of communication which is bound to the speed of light for this to work. The troops can then use these messages to triangulate their position. Orbital reconissance can also be provided by the ships in orbit. When you want ground troops to assign targets to ships in orbit, they can do so by sending the GPS coordinates to the ships. Should a poor soldier have lost their GPS receiver and only have their radio available to shout "blow up that thing a mile southwest from me", the ships in orbit can triangulate the source of the radio signal. You just need three ships in orbit to receive the radio signal. They can then do the GPS triangulation in reverse: They compare the times where they received the radio signal to calculate their individual distances to it and thus find the exact location from which the signal originates. [Answer] One existing tool which has been used for year is laser guidance. You have someone on the ground "designate" a target, and the bomb seeks in on that point. Its basically a super-fancy semi-active seeker where the target is lit up by a human who "knows" where the shot needs to go. If you don't have eyes on the ground or some comparative ability from orbit (like from satellites), then it may be wise to call into question why you need a precision strike against something you cannot see. What are you trying to hit so precisely anyway? [Answer] It seems to me that any properly motivated attacking force would have many, many ways in which to do this. First and foremost, deploy your own GPS sattelites, or hijack the enemy's. After all, you control the orbitals, so what's to stop you from hacking, or destroying their own network, and then launching new ones? If the enemy destroys them you can always simply launch more, or deploy smaller support ships with defensive weaponry at key points such that they act as guidance and triangulation beacons (GPS ships, as it were). This is absolutely vital, and you have no real excuse for not doing so. After all, your armada will be surrounding and attacking the planet, how are you planning to maintain communications if you don't establish a network of satellites or ships? The other major variable is the type of projectile you're launching. **Guided missiles** are very accurate, can hit mobile targets, and are generally easy to guide. All the troops need is to paint the target with a laser, or deploy a radio beacon, and the missile does the rest. However, they can be interefered with via electronic warfare, and if you're launching them from orbit they must first safely enter the atmosphere before striking their targets. You're better off deploying them on the ground and launching them from within the atmosphere IMO. When you want to take out enemy bunkers and strong points, however, your best bet is "dumb" artillery - aka dropping rocks on them. And these must be carefully aimed, because they're not going to discriminate against who they're squishing. The problem with these projectiles (rocks) is that you can't possibly aim them *that* accurately. Not only will you have a difficult time calculating the trajectory from orbit relative to planetary rotation (although this is doable), but you can't possibly account for all the trajectory adjustments needed for atmospheric entry, winds, etc. However, you can take the concept of dropping rocks, and come up with something a little smarter. Your projectile can be a massive chunk of metal with both a shaped heat shield, deployable fins, stabilizing thrusters for fine tunning the trajectory, and possiblly a gyroscopic stabilizer at its core. Once it has entered the atmosphere it can start tracking in on its target much like a missile, but without suffering from the same ... fragility. The damage it would inflict on its target would be based on the force of its impact, not due to any explosive payload it might carry (although antimatter, or nuclear warheads could be deployed in this fashion). [Answer] GPS is irrelevant. As the Battery Commander of a collection of orbital artillery pieces you need to know where to point your guns and how fast the projectiles should leave your guns' barrels. GPS is designed for troopers to report their position in a common frame of reference so that a battery without line-of-sight on the target can calculate the appropriate angles and weapon charges to deliver munitions to target. If your spacecraft are in low orbit (300-400Km above the surface) the flight time of your projectiles are ~1s and with "good enough" optics you could potentially take hand signals from the troops and aim manually at their targets. If your spacecraft are in a stationary orbit (~30 000Km for an Earth-sized planet), the flight times of your projectiles are ~100s. In this case, if you position your ships above the target, the trajectories will still be essentially straight lines (down) and with the crosshairs adjusted for the planetary rotation while the projectile is in flight, you will still be able to aim manually and hit your targets. Different orbital periods will complicate the trajectories that need to be calculated but the mathematics that allow a GPS receiver to locate itself on the surface of the Earth with timestamps broadcast from three different satellites on deterministic paths over that surface is called [Trilateration](https://en.wikipedia.org/wiki/Trilateration) (not Triangulation, Grr). The same mathematics are equally applicable to a collection of spacecraft that know their relative positions and each receive the same timestamp broadcast by a trooper on the ground. [Answer] While the WW2 they hit target out of sight with shells from a ship over the curve of the planet. With advanced tech their is so much way of doing it I don't know where to start. For triangulation you just need 3 points. Your ship, your troops, your target thats 3. You can keep track of your troops with a radar tracking a specific frequency that there communicator transmit, then the troop use material like a laser coupled with a compas or even simple instruction like : "500m north" and you calculate where to shoot. You can add precision with a high altitude drone that keep an eye on the action. Or even create your own mobile GPS with a net of drones. [Answer] You can use mountain peaks and ranges as your beacons. Triangulate three points and get your bearings that way. If there are no visible features for your ground troops, have the orbiting ship quickly 'scan' the planet and create a digital elevation model, DEM map(as detailed or undetailed as your require for your setting). Your ship then transmits this map to your groundtroops who use standard navigation techniques to figure out where they are and where they are going. Your troops can either transmit their calculated co-ordinates. If they are not accurate enough, your ship could use location beacons attached to your troops. These beacons would not be tied to a planetary GPS system but rather use the ship itself as an origin point. The ship can then determine the troops x,y,z distance from the ship. If you don't want to bomb your own troops, they can say that the target is 3 degrees, 14km from them and your ship takes the necessary reading from them and works out where the target is. Or they could just 'light them up' with those portable distance reading laser things. [Answer] The simplest thing if you have spacial advantage and lots of time - park in stationary orbit. Then you can do whatever you want and the result will land in pretty much the same location. Even if you had nothing else, you could do things like small drop at high speed to inhabited location nearby the target, and then approximate from it the changes for the final bombardment. ]
[Question] [ ## Backdrop This is set in a world after an empire-state that controlled the entire solar system fell. They have incredibly efficient catalyzed direct fusion drives, which powers [the heavy mining and shipping industry across the entire solar system](https://worldbuilding.stackexchange.com/questions/241031/what-would-be-the-ideal-reaction-mass-for-hall-effect-engines), sending cargo in and out of the outer solar system and between the planets. But there needs to be a solution to ferry light cargo and people on and off-world. These would mostly consist of light, extremely refined goods that cannot be made elsewhere, such as microprocessors, cryogenically-packed fruit and vegetables, and other goods only unique to earth. The vast majority of freight stays orbital, or dropped down the gravity well on single-use, dirt-cheap reentry capsules. ## Categories There are two broad categories we can split designs into. ### Space-Plane (launches sideways) A VTOL space-plane is a fantastic all-purpose craft, easily combining the functions of a helicopter, a plane, and a spacecraft. Any explorer or scout ship will probably have it as a shuttle. In this setting, it has modified turbojet engines on pivoting nacelles, scramjets along the lats, and two catalyzed fusion engines on the back. If you need fuel, you can skim off a gas giant. If you need a floating base of operations for a ground exploration, like on the side of a rough mountain, or a slow areal scan, then it can also do it. If you need to transfer cargo from one ship to another without docking, it can also do that. It's a jack of all trades, but a master of none. Its key advantage here is that it can hover over or land basically anywhere with enough space, regardless of terrain and with little regard for weather, or landing infrastructure. ### Basic Rocket (launches straight up) The other category is firmly in the same group as the Starship, built by SpaceX, except that it's a fusion-powered SSTO Starship. But still a Starship. It's a rocket that launches straight up, either air braking like the starship, or landing propulsively, like the falcon 9 and heavy boosters. It would also be reusable and if you had the technology to, and the delta V budget, be made as an SSTO rocket, making reuse even simpler. Unfortunately, this kind of ship can only ferry cargo up and down, and would require highly specialized infrastructure for engine plume management system, keeping the energy away from the craft itself, so it isn't damaged by its fusion drive. ## The Question What is the best design for a ship that does one thing, and only one thing: Get cargo from the surface into orbit, then bring cargo back, and repeat? Industrial fright transport. 1. A heavier and bigger delta-wing space-plane. 2. Something like [a heavy skiff](https://www.artstation.com/artwork/xYGE4O) and a landing bay, something like the Starship's chopstick arms, to have room for the deluge/engine plume management system. In the expanse, one of the [concept arts](https://www.artstation.com/artwork/eaPrXw) shows a heavy shuttle profile, slightly smaller than the Roci. 3. A shuttle variant, which takes a leaf out of the ISV Venture Star's book, and a little like [the lander](https://www.artstation.com/artwork/rRke2) from Destiny. It's a ship that is a compressive-tension truss, with its own (beefy) landing legs on the bottom. Above the folded legs are the stacks of cargo containers, covered with reflective material. Above it is the fusion reactor torus, and above it is the rigging, hinges and hydraulic shocks for an X shape of engine nacelles, angled away from the body. As aerodynamics becomes an issue, a shield/cone would sit above the engine pods, which doubles as the fuel and reaction mass tanks. Such a design negates the issues that a traditional rocket has, as its engines are far enough away from the ground for reflected energy not to damage the landing gear. (See the image link for visuals.) 4. Or maybe something totally different. That's my question. If you need to move industrial amounts of cargo on and off the surface, how? ## Side-note Sorry about asking the previous question, as clearly I didn't word it correctly, and didn't get the answer I needed, this should rectify it. [Answer] # "[Or maybe something totally different](https://en.wikipedia.org/wiki/Non-rocket_spacelaunch)" Bulk shipping operations doesn't want high performance spacecraft, they want **infrastructure**. Operating fleets of contained nuclear explosions (e.g. a fusion reactor) safely is expensive, as o.m pointed out with the Kzinti Lesson, not to mention the capital expenditure involved in each spacecraft. Meanwhile, in today's world, maritime shipping vessels use the absolute cheapest and dirtiest [bunker fuel](https://en.wikipedia.org/wiki/Heavy_fuel_oil) to minimize operational expenditure, and air couriers buy [secondhand passenger planes](https://simpleflying.com/cargo-operators-older-planes/) to save on capital expenditure. And of course, proper road and rail infrastructure is critical to overland shipping and economic development. Infrastructure-based space launch would consolidate high-tech, high energy technologies into a single hub, rather than spread out across the transport fleet. This would massively decrease shipping costs into space by simplifying operations of the actual spacecraft itself and take advantage of operational economies of scale within the launch center. # Types of Launch Infrastructure **[Beam-Thermal Rockets](https://en.wikipedia.org/wiki/Beam-powered_propulsion)** Instead of being powered by an internal fusion reactor, beam-thermal spacecraft would have their energy sourced externally, by wireless power transmission such as microwaves or lasers. **[Skyhooks](https://en.wikipedia.org/wiki/Skyhook_%28structure%29)** Skyhooks are long cables in orbit, rotating opposite to the direction of orbital motion, such that the ends are nearly stationary relative to the planetary surface when they are at the point closest to each other. This allows for small suborbital craft to dock with the skyhook tip and be carried into orbit. Here is a Kurzgesagt video on the subject [https://www.youtube.com/watch?v=dqwpQarrDwk](https://en.wikipedia.org/wiki/Skyhook_%28structure%29) **[Electromagnetic Launch](https://en.wikipedia.org/wiki/StarTram#Generation_2_System)** A massive coilgun accelerating payloads to orbital velocities at close to 1 G over 1000s of kilometers of land, typically exiting at the peak of a mountain range. **[Loftstrom Loops](https://en.wikipedia.org/wiki/Launch_loop)** A Loftstrom Loop is a rapidly moving looped belt being held up by its own momentum, supporting a massive bridge holding up an electromagnetic launch system above the atmosphere. **[Orbital Rings](https://en.wikipedia.org/wiki/Orbital_ring)** An Orbital Ring is created by extending a Loftstrom Loop to circle around the planet's circumference, rather than looping at two points on the surface. **[Space Elevators](https://en.wikipedia.org/wiki/Space_elevator)** The classic Space Elevator, a cable capable of withstanding [enormous tension](https://en.wikipedia.org/wiki/Space_elevator#Cable_materials) (and not being cut) is tensioned between the planet and a counterweight (say, an asteroid). However, because the cable "orbits" the planet at the speed of planetary rotation, the elevator would have to dock at a geostationary orbit. If a moon is tidally locked to its planet (e.g. Earth-Moon), a space elevator could be built out [from the Moon](https://en.wikipedia.org/wiki/Lunar_space_elevator) its [Lagrange Points](https://en.wikipedia.org/wiki/Lagrange_point), which also are locked in a similar manner. And if two bodies are tidally locked to each other (Pluto, Charon), [an elevator could perhaps be built between the two.](https://space.stackexchange.com/questions/5193/space-elevator-between-doubly-tidally-locked-bodies) [Answer] **With sufficiently efficient drives, think of the landscape.** Launching a chemical-propellant into Earth orbit is so difficult that torching the launch pad is among the least of your concerns. Just think of the stages that get dropped along the way ... With a hyper-efficient drive, you **can afford** to worry about the blast effect, and you also **need** to worry about it more. Larry Niven called this the [Kzinti lesson](https://tvtropes.org/pmwiki/pmwiki.php/Main/WeaponizedExhaust) -- "a reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive." So instead of doing VTOL, and toasting the tarmac, do HOTOL and toast the air behind the spaceplane. You could of course have both, with different roles and drawbacks, if your style includes technobabble. *"What was that?" The detective stared at the wrecked hangar. "That is what happens when a spaceplane uses the engines in an enclosed space and not on the runway. The backblast got them, too. No survivors."* --- *"600 meters." "Stand by to expand the drive focus and increase flow on my mark." "500 meters. ... 400 meter, sir, should we-" "Mark." At the touch of the switch, the magnetic nozzle reconfigured and the stream of reaction mass became a torrent. Even so, the deceleration was reduced to 2 G. The cargo lander settled in a cloud of dust.* --- *"Have you ever been down in a lander? A bit more, hmm,* energetic *than a passenger spaceplane." "Not since I was in the Marines."* [Answer] > > Unfortunately, this kind of ship can only do one thing, and that is launch things into orbit and bring them back. > > > Well... Hold up there Hoss. See, when we look at real-world applications, especially in Heavy mining and Industry - we find a plethora of Vehicles that specialize in doing one thing and doing it excellently. For a planetary scale shipping endeavor - the cost of building a number of highly specialized vehicles for ferrying cargo from the Ports/Terminus on the ground into a stable Orbit, where they can be loaded into interstellar vehicles is minimal compared to the revenue generated by such a large-scale application. I would imagine that with the exception of certain specific cargos, the preferred method would involve the futuristic equivalent of a Shipping Container - e.g. a standardized unit for moving - so I'd expect to see Space Vehicles built around this. Depending on your desire to invent Tech - my thoughts would be something like an Aircraft carrier catapult, possibly a Mass Driver type system. This would accelerate the launch vehicle on the ground with enough speed/energy to get into the thinner atmosphere where Rocket engines can work more efficiently. This is to reduce the Fuel/Energy needed in that initial phase from being carried on the vehicle - Every kilo that isn't cargo that you need to shift into orbit is a Kilo that isn't profitable - and that initial phase is where you have the most atmospheric Drag - so offloading some of that requirement to an external device would be good. [Answer] > > a ship that does one thing, and only one thing: Get cargo from the > surface into orbit, then bring cargo back, and repeat? > > > **Cargo ship with rockets.** [![cargo ship w rockets](https://i.stack.imgur.com/vu1Bo.jpg)](https://i.stack.imgur.com/vu1Bo.jpg) You made it easier for me because you called it in the OP. > > Unfortunately, this kind of ship can only do one thing, and that is > launch things into orbit and bring them back. > > > Thats what it does. No fru-fru. Other ships take care of all that. This is a heavy lift up, then fall back down and brake before break. Rinse. Repeat. [Answer] The answer is very obviously **a spaceplane**. And not like the stuff you describe in your first paragraph. There will NOT be VTOL capabilities on the commercial ones. That's just unnecessarily added weight and complexity. Air-breathing engines with bypass-thrust are simply magnitudes more efficient than any rocket-like contraption you could build, as long as there is air to breathe and move. The wings also mean that you don't have to actively burn against gravity while accelerating for orbit (remember: Orbit isn't that far up, it's mainly going sideways fast). We might see foldeable wings because on the way down you need much more rigid but smaller ones than going up, but there will be wings. SpaceX doesn't need them because they just land empty rockets with pretty much zero weight. They're recovering their plane, 0 cargo. And having to carry up fuel just to slow down on the way back is an absolutely unnecessary cost factor. Edit-Addition: Alternatively a two stage Virgin-Galactic kind of system could be in use. A Rocket consisting of mostly payload would be carried as high as possible and then launched the rest of the way into orbit. This would still mean that the expensive bit of rocketry (all the time spent at or near ground level and the forces necessary to escape from there) can be negated by proven-efficient plane technology. Even more stages including RAM- and SCRAMjets could also be thinkeable for increased efficiency. Generally this system would not only be cheaper, but also have a higher cadence per infrastructure than a classical spaceport [Answer] ## Bulk Freighters will be Ovoid shaped. When it comes to optimizing structural integrity with air resistance, the best shape is an ovoid (egg shaped). The forces involved in atmospheric acceleration and re-entry are significant, and the larger and heavier you get, the more integrity becomes the biggest issue you face. Making a long skinny rocket shaped ship will suffer more crush force over its smaller cross section as you get too big, a perfect sphere would have too much drag, and anything with sharp corners like a cube is less structurally sound under the heat and stress. Wings are especially fragile as you scale up in size and speed; so, while space planes are great for smaller loads (100 tons or so), they would be terrible for larger ships. [![enter image description here](https://i.stack.imgur.com/JmPYn.png)](https://i.stack.imgur.com/JmPYn.png) ## Container Ships In real life, goods are typically transported either via bulk carrier for transporting massive volumes of unpackaged products or container ships for when you have lots of smaller parcels to deliver and distribute like consumer goods. Ovoids will of course be perfect for bulk carriers since things like grain, water, ore, fuel, etc. don't really care what shape they are in, but container ships will require a bit of extra engineering. Shipping containers are cuboid for many reasons. They are ideal for putting smaller boxes into, they make good use of the space, and they are able to be directly loaded onto trucks for transporting the maximum amount of goods for distribution. So it is best not to mess with the cuboid shape of a shipping container, but it does lead to concerns about how tightly you can pack your cargo in a spheroid. For it's length, width, and height a spheroid has ~47.6% less internal volume than a cuboid. So, while cubes can't survive high delta-Vs or air breaking nearly as well as a sphere can, they may still be the ideal solution. High Efficiency Fusion engines are crazy cheap to operate compared to traditional rockets, and are basically immune to the [tyranny of rockets](https://www.nasa.gov/mission_pages/station/expeditions/expedition30/tryanny.html) problem. Assuming Perfect Efficiency, each ton of cargo fired at traditional Delta-V only requires about 2 grams of hydrogen fuel. Let's say we consider "High Efficiency" to mean some fraction of perfect. Now we need to make up some exact number for what "High Efficiency" means... but I think most people will interpret this to mean some tangibly large fraction of the total energy. Conventional Rockets are about 70% efficient; so, let's go with that and say you need about 3g of fuel per ton. This means that the fuel cost per ton of launch weight is about /$0.003/ton if you are using hydrogen fuel. While some of you might be thinking that fusion will require much more expensive deuterium, tritium, or He3, current research into fusion technology predicts that heavy versions of hydrogen can be created as part of the nuclear process before we reach economic viability, much less high efficiency. So, plain old hydrogen is the most likely fuel source at this tech level. The reason this is all so important is that it means you don't need over 4G of acceleration to get to space on a budget. A cuboid container ship will need to burn a lot more fuel and move a lot more slowly than an aerodynamic round ship, of similar mass, but the cost of getting to space will still be super cheap. Even if you burn 10x as much fuel going up at a modest 0.5G all the way. That still places your at only 3 cents per ton in fuel costs... now the extra weir and tear on your thrusters will likely be a lot more expensive than that, but the extra efficiency of stackable containers should still out weigh this fact. For structural reasons, you will still want your ship to have a rounded bottom (plus you want them to be able to use the same ports as bulk carriers); so, the whole bottom will be the same as the other ships, but the top section can just be shipping containers bolter together in a more or less cylindrical pattern. More cubic shaped designs will be oncourse be viable for smaller container ships. [![enter image description here](https://i.stack.imgur.com/jUhKW.png)](https://i.stack.imgur.com/jUhKW.png) ## Space Port Design Space port design will work more or less like a normal modern rocket pad. But because you have "incredibly efficient catalyzed direct fusion drives", you can handle WAY bigger payloads using the same space port technology. The largest rockets used today weigh about 4000 tons with a 150 ton lift capacity, but with direct fusion drives your fuel efficiency is about 500,000 times better than Rocket fuel; so, a 4000 ton ship needs only needs about 11.4 to 100ish kg of fuel to reach orbit depending on if you are trying to maximize your delta-V or just make it as smooth of a ride as possible. Furthermore, traditional rockets have a much smaller base section than these ships meaning that issues like distance to landing struts, sonic and thermal kick-back etc will be more spread out and less of a problem. In fact, height, and not total size is a much better gauge of how hard it is to make an appropriate launch platform; so, using the squattier designs like the ones shown above could easily be 10x the mass of a Saturn V Rocket, and not require any additional technology to make an appropriate launch-pad for. You just need to make it wider. Furthermore you can overcome many of the things that make normal VLS rockets difficult. In a normal space rocket, your goal is to accelerate as fast as possible with as little complexity as possible because the more time you spend getting off the ground, the more total Gravity you have to overcome. This is especially complicated at take-off because that means your first stage rocket gets a lot of kickback both in terms of heat and sonic reflection. We currently solve for this by shooting up jets of water at the thruster as it takes off which absorbs the heat, boils, and then the bubbles absorb the sonic feedback. The other thing we do is limit initial takeoff accelerations to about 5m/s^2 (which is much lower acceleration than once it gets away from the pad). However, in a ship where fuel is less of an issue, you could limit takeoff acceleration to much slower (1m/s^2) reducing actual downward thrust and kickback at launch and landing time at the cost of using a bit more fuel. This means that you could go an additional 50% bigger (in all directions) and modern space pad technology would still get the job done. This places the maximum mass of a heavy freighter somewhere in the 135,000 ton category when fully loaded... though I suspect something in the 40,000 ton weight class may be more common since throughout most of civilization, the majority of cargo ships seem to be about 1/3rd the mass of "top-end" ships because it makes building to tolerances much easier. Given this size, economy of scale, and figures taken from various sources, I'd estimate this as being 15-30% ship/fuel, and the remainder of the mass as cargo. As for how expensive these space ports are... they are not really more expensive than a normal airport. Yes you need a large exclusion zone because of the power of the thrusters being so loud and hot, but because it is a VTOL design, you don't need long paved runways; so, a fairly small total facility in the middle of the desert or a small rocky peninsula would suffice. That said, smaller versions of this design would not need specialized launch pads at all. 50 ton ICMBs can be launched directly from the back of a truck in the middle of a normal road; so, smaller ships with this wider profile (500 tons, maybe even bigger) could still be launched and landed safely from open fields or simple paved surfaces just like these 50 ton missiles. In all reality, your fusion engines should mostly make space planes obsolete since anything too big to VTOL will also be too big for wings. The biggest application I see for space planes will be where sustained in-atmosphere maneuverability and speed will be important or if fusions reactors simply need to be to big to work with smaller ships, and you need good old fashion chemical propulsion for smaller crafts... so, you'd probably still see them used for military purposes where you need aircraft that can perform both air and space missions and/or for non-bulk purposes. [![enter image description here](https://i.stack.imgur.com/XstDy.png)](https://i.stack.imgur.com/XstDy.png) ## Do you really need ships that can carry 100,000 tons? > > ... the transported cargo (up to space) would mostly be small, extremely refined goods like microprocessors, cryogenically-packed fruit and vegetables, and other goods only unique to earth. The vast majority of freight stays orbital, or dropped down the gravity well on single-use, dirt-cheap reentry capsules. > > > Because you have such cheap fuel, it is actually better to not do this. Fusion engines and reactors are very expensive and hard to make... but a few kg of hydrogen is very cheap. In fact the total fuel cost of launching 100,000 tons of cargo into space would be between about /$400-4000 in today's economy. In terms of shipping, that is dirt cheap. **You could potentially run hundreds of missions with a reusable heavy freighter for less cost than it would take to build 1 single use rig.** This means that you want to have a 2-way freighter designed to go both ways and be reused over and over again. This is very different then modern rockets where the fuel is really expensive and the rocket is by comparison cheap. Even if your return trip back to space is only carrying a few tons of processed good, for every 100,000 tons you are bringing down here, it's still worth it. Being able to send your fusion engine assembly back up into orbit is already a necessary cost, so might as well use the ships you've already got... not to mention, manufacturing and refining on Earth will be much cheaper; so, most if not all ships, ship parts, and fuel production will need to be done planet side anyway. [Answer] **Use both for different applications** what you are describing is a type of spacecraft I'd like to call a shuttle, an SSTO spacecraft designed to move cargo and people in and out of a gravity well. I'd use a VTOL spaceplane design for an atmospheric passenger shuttle, as aircraft tend to not apply a lot of G-force on passengers that may not be used to high G's. these would probably require specialized landing pads and an atmosphere to function. Rocket SSTO shuttles could be used for ferrying large amounts of cargo and on bodies with no atmosphere (such as Earth's moon). these just shoot the cargo containers (or people) out into orbit for a swift 15-minute accent, but at the cost of extremely high g's, so only ai pilots or human pilots that have trained their bodies to survive the accent. they may also be able to land on most solid surfaces and be over all less complex than VTOL Space planes, so they would be a good choice for early colonization of planets. VTOL Spaceplanes and SSTO Rockets aren't the only methods to shuttle things on and off worlds, a disposable space crane could be a cheap alternative to these systems, at the price of reusability and carrying capacity. Probably only good for getting cargo to the surface of a body. Other uses for these craft types besides surface-to-orbit transfer: * A space plane could dive into an atmosphere, travel along a straight line, scout out the planet, do some quick atmospheric science and ascend up out of the atmosphere * short-range orbit-to-orbit transit in a rocket SSTO (I.E from Earth to luna or between the moons of a gas giant) * any shuttlecraft type could be used as a lifeboat in case of emergency, so long as you can stuff it full of crew (see s1 ep 1&2 of the Expanse) * as a bomb/missile (see s4, ep 10 of the Expanse) [Answer] Assuming no crazy sci-fi tech, like space elevator, I feel that Starship-like reusable rockets would be best. With fusion that you have mentioned, it would reduce risk of dealing with tons of fuel and oxidizer. And would allow for faster turnover. But it would be only for one-way trips from ground to orbit. Similar system could be adopted for getting stuff from orbit to ground. A container would be attached to a "descend module". This would be a heat shield with a landing parachute or rockets. A booster would then be attached, which would deaccelerate the module, so it starts air-breaking. The booster would detach before that and boost back up into orbit to be reused. The main issue with the above system is that it is not kind to the cargo. Both Gs and shaking puts limits on what kind of cargo and people can be carried. With fragile cargo, you risk breaking it. And most people would find it uncomfortable or even dangerous to travel like that. If you want to be more kind to your cargo, you would definitely need a shuttle-like aircraft. It would be strongly aerodynamic and need two types of engines. One to get off the ground and into air and sufficient height. Then, it would use the fusion engines to slowly accelerate into orbit. It is the return trip that is the difficult part. The design would need to avoid air-braking to reduce stress on people and cargo. This would result in "weird" design where the engines would also face forward. This is to reduce the aerodynamic drag when going through upper atmosphere, while also being able to slow down slowly and gradually. [Answer] ## Use single use re-entry vehicles This answer will probably not make you happy, but you may find solace in it being much more grounded in current tech. As described by [Tsiolkovsky rocket equation](https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation) any rocket-like vehicle will be inherently limited in the amount of weight it can transport so it is best to avoid it entirely. Instead of lifting materials from planets, I suggest that most materials and products would be manufactured in spaces and dropped on planets with single use vehicles. If raw materials were shipped from orbit to ground, the eartbound vehicle could be extremely simple as a large chunk of homogeneous material is likely very resilient. The empire state could conceivably use VTOLs for passengers, critical supplies, VIPs, secret documents and such, so there shouldn't be a lack of coolness. However with very large volume of product landing earthside with parachutes. This answer does not take into consideration space elevators / coil guns of any sort. [Answer] I would like to suggest [Skylon](https://en.wikipedia.org/wiki/Skylon_(spacecraft)) for transporting people and their hand luggage. Most stuff you have taken into space is probably more valuable in space because you have put the effort into lifting it. If most of the weight is coming down some other way, then the transporter for the remainder will be very plane-like. [Answer] ## Spinlaunch plus skyhooks **Spinlauch** is a great system if you don't have to take squishy humans along. It is made to move cargo. It works even better if it only has to reach lower orbits at an angle. Combine it with skyhooks and you can scalable fuel minimizing launch system. Fusion gets you energy not fuel, you still need to minimize fuel to keep your rocket equation economical. Spinlaunch gets most of its impulse from a ground based powerplant, with only a small fuel component (even less if it only has to reach low orbit). It is a high G delivery system, horrible for living things, great for cargo. Essentially spin a counterbalanced system up to high speed in a low pressure environment then throw the rocket most of the way with only a small rocket component. You can see a great breakdown of how it works [here](https://www.youtube.com/watch?v=yrc632oilWo). [![enter image description here](https://i.stack.imgur.com/cwVK7.png)](https://i.stack.imgur.com/cwVK7.png) **skyhooks** do one thing catch things in lower orbit and move them to higher orbit or vice versa for virtually no fuel. With high turnover cargo as long as you have roughly the same mass going down on average as going up, it works for practically free. Unlike space elevators you could build one today. Better yet it gets cheaper to run the more you use it since it gets its energy mostly from its cargo. for some great idea try the Kurzgesagt [video](https://www.youtube.com/watch?v=dqwpQarrDwk) on the subject to see just how far you can take tethers just using existing materials. [![enter image description here](https://i.stack.imgur.com/DTDfH.png)](https://i.stack.imgur.com/DTDfH.png) Combine both technology and you have a system that can move non-fragile cargo very cheaply. Nothing you describe is fragile to these kinds of G-forces. [Answer] There are plenty of excellent ideas for this that have already been said, but I have an idea of my own. A variable-wing spaceplane could fill this task nicely. It could take off with its wings folded (Since your universe powerful engines, this shouldn't cause a lift problem. Anything with a powerful enough engine can fly.) to reduce drag. It could then dock with an orbiting freight station, transfer its cargo, undock, and reenter the atmosphere. It would unfold its wings to slow itself down, and glide like the space shuttle for landing. ]
[Question] [ So. I've come up with a live-action video game, essentially like Ready Player One or The Matrix. You put on a helmet, which then intercepts your brain signals and causes you to enter a virtual reality. The game itself is an escape-based game, where you have 1 hour to get into the next level. Of course, going through 20 or so levels like this would take a long time, even if you beat each level first try. So, I decided I needed to make time go faster for those in the game than for those outside the game. I would prefer each level to last around 5 minutes for the real world (despite being an hour for those inside the game). This kind of speed up would be tough on the brain, so how can I help mitigate that from being a major problem? In response to comments:(TurtleTail) You are able to leave the game between levels, simply by pressing a button which allows you to take off the helmet and continue with your life. [Answer] In theory the simulation itself wouldn't be the problem, you can easily run something designed to play for an hour in 5 minutes, just like you can fast forward a movie. However the issue is that the brain would need to be able to keep up, otherwise it would actually just appear as a sped up movie and not like an hours long game. I can think of two ways to get around the problem. Either by actually speeding up the users brain somehow. Or to link it to a dream like state where the actual gameplay elements would be a couple of minutes then coerce the brain to fill in blanks with dream like memories and emotions in between. Depending on your setting both could be viable. Be weary though that the first option includes the actual capability to "do an hour of thinking" in a couple of minutes. This kind of tech would ripple through your entire world with all it's possible up and downsides. [Answer] ## Gradually speed up your levels In the old days, when we played [Tetris](https://www.google.com/search?q=Tetris), it was comfortable to play the first 4 levels. The game went very slowly and you had all the time of the world, the Tetris bricks would take 10-15 seconds to fall.. enough time to learn the proper keyboard keys to turn-and-drop the brick. Later on.. level 11, the speed of the Tetris bricks required a turn-and-drop decision in about 500 miliseconds. The previous levels seemed dull to play. Looking at your screen, the outside person watching your level 11 Tetris wouldn't be able to keep up with your fingers and gets to think you must be clairvoyant, or know all the moves.. [Answer] *You don't justify your premise that the brain would have trouble dealing with the faster in-game time. I play games right now where the in-game time is faster than real-time and I don't even get a headache. The movie* Inception *justifies its premise using the suspension-of-disbelief assertion that time passes faster in a dream than in reality. There doesn't seem to be a real problem here (other than you won't simply state that as a rule of your world people can process faster in-game time than reality time without harm), but for the sake of argument, let's say there is one...* **Reduce the detail** People get confused, headaches, even very real psychological problems because too much detail is happening too quickly for the mind to process. Heck, amusement parks *depend* on this human limitation for most of their fun! The problem is that, barring an act to block things, you can't actually stop your brain from hearing all the noise going on around you or from processing everything it sees to the level of detail the eye permits, or from smelling everything that's out there. Except that the brain actually does stop those things. Automatically it will filter out noise it doesn't want to listen to (within limits, an air horn is awfully loud) or things it doesn't want to focus on, or smells that have been around too long. **You need to do the same thing in your game** You need to pre-filter the detail so the enhanced speed doesn't overwhelm the mind. Humans can frequently see individual leaves on trees from an awfully long way away — but is it actually necessary to have that level of detail in your game? While our eyes *can* see that detail, what we end up *comprehending* is that the trees behind the person we're talking to are green. Pre-filtering also has the advantage of allowing you to control the flow of the game by forcing the focus of the player to be drawn to necessary detail rather than unnecessary detail. Pre-filtering is also valuable economically as computer time isn't wasted rendering details that serve no useful purpose in the game. Honestly, do you actually *need* to see the pores on your friend's nose when you're talking to them? Reduce the detail to reduce the distraction, control the flow, and be economically efficient. And at the same time you'll save their brains, which is a good thing because they'll be needed when the zombie apocalypse starts. [Answer] **Not realistically, or not much** There is a hard cap on how fast a human can think. Specifically, there are neurochemical reaction speeds to contend with that simply take time. Thoughts don't happen instantly, and reacting to any external stimulus has a delay. Specifically, it is widely recognized that a human has a reaction speed of around 250ms to visual input to execute a "prepared action". This can be reduced with training to make a specific reaction instinctual instead, and there are some studies that show you can increase reaction speed by eating specific foods, but generally, reaction speed is something that's mostly determined by fitness, age, and genetics. Interestingly, as the information-bandwidth that you need to react to decreases, reaction time decreases too. Reacting to a sound is faster than reacting to something visual, and reacting to a touch sensation is even faster, reaching about 150ms. That said, in certain scenarios, time acceleration is already used. Many people listen to audiobooks or podcasts at an accelerated speed, and switching a video to play at a higher speed is also rather common. Unfortunately, the human mind is simply limited on how much "bandwidth" it can intake per certain amount of time. From personal experience, I know that I can watch a video at 1.25 speed and only negligibly impact retention, but when I crank it to 2x speed, I *need* to turn on captions to keep my information retention high because I simply can't process all the video and audio at the sped-up pace but I can read and comprehend at that pace. You can try this at home. Pick an information-heavy video, and crank the speed until you reach the point where you aren't understanding anything anymore. Because of this, I don't think you could crank the speed of a VR or even a "Full Dive" significantly. Maybe if you start off slow, you could crank the speed by a couple percentage points: TV channels have gotten away with cranking speeds to 104% to increase advertiser time with only very few people noticing, but anything more would immediately be noticed and likely perceived as very uncomfortable. Maybe, provided your equipment can interact deeply with the brain or people take reaction-speed increasing drugs, you could crank it into the tens of percentage points (110%, 120%) but anything more would likely be uncomfortable and disorienting. [Answer] It all depends on whether the human brain is overclockable. Does a human brain even have a clock speed (and are humans more intelligent if theirs is raised significantly... or do they just arrive at the same conclusions more quickly)? If the human brain operates on principles significantly different than one where a clock speed metaphor is appropriate, then time can't go faster in the Matrix without the inhabitants of it being incapable of "keeping up" with the events in the Matrix. On the other hand, even if it does have a clock speed, the methods and technology to ramp that up seem far-fetched. Meat just isn't that quick. Signals only propagate along synapses so fast, proteins can only be synthesized so quickly, etc. Most of the sensations of a dream having lasted much longer than the sleep that it was born from have to do with malfunctioning faculties that let an awake brain track time. [Answer] Why does the escape room take an hour? Well, we know it doesn't. It takes 5 minutes. But it sounds like your goal is to have the humans playing it *perceive* an hour has past. [Chronoception](https://en.wikipedia.org/wiki/Time_perception), or the perception of time, is an intriguing topic because we really don't understand it yet. We have many hypotheses about how the brain links together events to from a cohesive stream of time, but hard neurochemical arguments are hard to come by. You could easily pick one of these theories and argue that your game stimulates the brain carefully to create this illusion. However, the harder challenge would be "overclocking the brain" as others have put it. The brain can only think at a certain pace. You would not be able to simulate a nice leasurily drive through the countryside with a simulated F-1 car careening around corners. The decision making has to happen too fast. One interesting thing you could play with is the theory that "time slows down" for people in high-adrenaline environments like sky diving. Studies have shown our brain doesn't actually operate faster in these environment, processing stimuli as it always did, but it does seem to respond faster. You could argue that this is because the brain is "disconnecting" the slower higher order thought processes and falling back on the more instinctive paths through the neurons. This could be troublesome for an escape room, where typically one is relying on higher order thinking, but you may be able to re-invent the escape room to reward more flowing forms of thinking. Indeed, there are some who argue that there is a "flow" state where data progresses through the brain more laminarly than usual. If the game encourages people to enter this state, it will be easier to generate unusual chronology. That being said, the answer may be a writing solution. *why* does the escape room need to take an hour? What purpose did that provide? If the idea of the book is that people spend hours in these games and then are suddenly confused that little time has passed, then you'll have to have this particular perception. If you just want a scene which plays out as-if it were an hour long escape room, there may be writing ways to avoid needing such longevity. [Answer] I think the best way to handle this is to sidestep the question of "can you speed up the brain?", if you're okay with a pretty advanced technological level you could have the device scan the brain, recreate it digitally and put the real one to sleep. Once you have that simulated brain created you can make that simulation run arbitrarily fast (dependant on the available processing power), the player wouldn't actually experience the game, but an exact digital copy of themselves would. When you log out of the game, the memories of the replica would be inserted into the real brain, the digital brain would be purged and the real one woken up. This method essentially bypasses any biological speed limit that the brain has, the only thing to worry about is "writing" memories into the brain. It's definitely far past the technology level of Ready Player one, but close to The Matrix. (The method does open the door to some weird philosophical situations if the technology is flawed, stuff like a replica surviving the purge and a person existing in multiple forms at the same time, but you can ignore these if the technology works reliably) [Answer] The first point is that you really can't speed up the human brain. They've performed experiments attempting to recreate "flashbulb memories," where it feels like time slows down, but what they've learned is that your perceptions don't speed up, your brain just retains more information after the fact. They've demonstrated this in experiments with fighter pilots. The pilots develop a [more organized brain structure](https://www.ucl.ac.uk/news/2010/dec/fighter-pilots-brains-are-more-sensitive) [through training](https://www.bbc.com/news/health-11992270), but it was very task-specific. You can improve reaction time to a specific task, but that speed improvement is entirely in [problem recognition time](https://fs.blog/ooda-loop/), not resolution time. Improving recognition time also makes the person more susceptible to false positives. What you can do is reduce the intermediate garbage. Most of a person's time in an escape room involves moving from one place to another to find the next set of clues. If you make the escape room twice as big, it takes twice as long (roughly), even with the same set of puzzles. If you want it to take less time, you can reduce "travel time" in the virtual world. [Answer] I recommend you take a look at [Accel World](https://en.wikipedia.org/wiki/Accel_World), a Japanese novel and animation where the players of the game enter a world where time is accelerated 1000 times. It enables the players to enter and exit a game while standing at traffic lights or wherever, and be back in the real world fast enough that there is little danger from 'zoning out' in a public place. The author's reasoning behind the ability to accelerate time is that time is related to the speed of your heart beat. He proposes that when people are in love, or in an emergency situation, your heart beats faster and your consciousness slows down. By that logic, if the game can accelerate your heart beat, it can also accelerate your consciousness, causing time in the game to pass by much faster than in real life. Of course, this idea presents lots of other questions, such as, is it really healthy to speed up someone's heart so much that their consciousness is accelerated 1000 times? But then, it's fiction, so the science doesn't need to be perfect. ]
[Question] [ An evil emperor wants to conquer the Galaxy. Before sending humans he wants to send out an advance force that will subdue other life-forms. The Emperor's Adviser comes up with the idea that the Empire should send out DNA-based life-forms that are as hardy as possible. These are to be cockroaches. They are to be genetically engineered to have a DNA 'off-switch' so that when humans finally arrive they can remove the entire population of cockroaches who have already done the job of wiping out alien life-forms. **The plan** Standard Earth cockroaches (with the DNA off-switch) are to be placed in containers that are fired in random directions throughout the galaxy. Some will crash land on planet surfaces and break open releasing the cockroaches to devastate the local biosphere. **Question** Are cockroaches the optimum vector for doing this? Would they survive the journey, the crash-landing and would they be able to colonise other worlds capable of supporting carbon-based life? If not, what would be better? **Note** I'm assuming that all non-Earth life-forms have evolved separately and so do not have Earth DNA - or even DNA at all. Because other vectors such as viruses for example are adapted only to attack creatures with Earth DNA, they would presumably be ineffective against alien life forms. [Answer] # Cockroaches don't live up to their reputation. The domestic cockroach that seems so hard to kill is as dependent on our warm comfortable environment as we are. If you want to clear an infestation in a cold climate, just leave the heating off, the windows open, and go away for a couple of weeks. The cold will kill them all off. # Locusts on the other hand do live up to their reputation. As long as the local flora is edible and the temperature is within a suitable range, locusts will breed to plague levels and devastate the vegetation across vast areas. # Cyanobacteria Also known as blue-green algae, while often not blue-green and never algal, these bacteria are possibly one of the oldest forms of life on the planet. They photosynthesise so you don't need to worry about local life forms, any nutrients will do, they really like nitrogen rich water. In effect they range from skin irritant to neurotoxic, they also have a tendency to form massive blooms in fresh water leaving it poisonous to many animals. [Answer] Cockroaches and other animals **need food**. It is very unlikely that planets around galaxy will have life forms that are compatible with us - even on our own earth many organisms can't digest cellulose and mycochitin, and on other planets evolutionary paths will be totally different and unrelated. What you need is **something with photosynthesis** - simple plants, cyanobacteria, generally low level [pioneer species](https://en.wikipedia.org/wiki/Pioneer_species). That would at least give them a chance. Chemo and radiosynthesis, and other possible forms of making own nutrients are risky, you can't really be sure there will be appropriate energy source available. Light is pretty universal, so it is a safest bet. [Answer] First problem. # Animal life is a parasite on plant life. Cockroaches breathe oxygen released by photosynthesis, consume plant matter that was created by photosynthesis, eat animal matter that in turn was fed by plant matter created by photosynthesis. The animal isn't capable of building its own nutrients, but rather relies on the complex organic molecules the plant has built. In an ecosystem that the animal did not evolve in, the organic molecules the plants use (for structure and energy etc) could very well be completely incompatible, leading to animals with in turn completely incompatible biologies. If you consider this unlikely, the story of trees and coal should fix that. Trees (and hence wood) evolved many millions of years before organisms that could break down wood did. So huge piles of unrotting wood built up. These huge deposits of carbon are what most of our coal deposits are made out of. **Millions** of years later, white-rot fungi finally figured out how to rot wood. And it stopped happening. Our life forms co-evolved to eat each other. The cockroach could arrive, eat things, and find nothing provides it with enough energy or nutrients to live. What more, everything could be poisonous or toxic to the cockroach. Macroscopic life on Earth is relatively recent, and it exists in a specific kind of life-modified world. A different biology or ecology could easily result in an atmosphere poisonous to cockroaches and organic matter it cannot get energy or nutrients from. Second problem, # Space is big Firing stuff in random directions in space won't hit planets. Hitting a planet (besides Earth and the other planets of the Solar system) by firing in a random direction would be like firing a gun in a random direction, and hitting a specific target on the other side of the planet, 1000 times in a row. Gravity won't "pull you into" planets, but would almost always just swing you into a new direction. Next problem, # Stars are far apart Launching something at a speed that it would reach the other side of the galaxy before, say, the Earth is swallowed by the sun, requires insane amounts of energy and technology. Stopping such a projectile requires you to package insane amounts of technology and energy *into the projectile*, which is exponentially harder. And then we reach: # The Galaxy has lots of stuff in it Suppose you have perfect aim of star wisps. If you fired one per star, that is 100 billion stars. We are already talking about a task that the entire human civilization couldn't pull off once, and you want to do it 100 billion times. --- You need to rework your plan. Start with a star-wisp based self-replicating mini civilization. This is already insanely hard, technology wise. You launch a dozen or so of such wisps. They fly to nearby stars, quickly check for raw materials. If they see it, they stop. They then try to bootstrap their own industrial civilization. After, say, about ten thousand years, 1 in 10 of them have the ability to launch star wisps in turn. Each launches a dozen wisps, at a rate of 1 every hundred years. (These are expensive to launch!) So every ~10,000 years, you get 1.2 times as many wisps as you had the previous cycle, and start with 12. To reach 100 billion wisps this takes 139 cycles, or just over a million years. In practice, you are going to be more limited by the speed of light than replication rate; the galaxy is 100,000 light years from end to end, and your star wisps are probably moving slower than 0.001c (get going faster than that, then stationary atoms in the interstellar medium hit you like hard radiation. Not good). As with all exponential growth functions most of the growth happens in the last part, so after the local corner of the galaxy gets saturated you'll have a relativistic speed (even 0.001c is relativistic) wave of star wisps leapfrogging each other to colonize every system it can. This star wisps armada can then build simpler things, like customized biological weapons, to disrupt any ecosystem it finds. However, more likely and usefully, it could instead seed dead worlds with life, or even try to redirect the ecosystems of worlds towards complex multi-cellular life and/or an oxygen atmosphere. What more, 3d printing a human is a simple task compared to creating star-wisp producing civilization. So the armada could switch from spreading to invasion after it sets up a beachhead; the invading biologicals could be printed humans. [Answer] ## It is unlikely for something like this to work Your falling point here, like pretty much all questions about alien fauna/flora, is [Chirality](https://en.wikipedia.org/wiki/Chirality_(chemistry)). If the planet your cockroaches land on has the wrong chirality, the cockroaches will not be able to derive any nutrition from eating the flora/fauna, and may in fact have lethal allergic reactions to it, quickly killing off your pests. This is, of course, passing over the issue of maintaining a breeding population of cockroaches whilst they travel the depths of space, or the inherent problem that if the cockroaches eat 99% of the local flora/fauna, your cockroaches will have no more food and starve, potentially leaving some remote natives alive to repopulate. It'd be much more efficient to launch a set of Von Neumann Probes to hunt down and eradicate life. Just make sure that the kill switch is the last thing to mutate though, unless you want to become a cautionary tale after your robots sterilise your home world. As @Kieran mentioned in a comment, a way to use Von Nuemann Probes whilst sticking with the DNA theme would be to have them analyse the environment, before designing and manufacturing a set of invasive species (specialised for this world) to destroy the natives. Perhaps your probes could collect the DNA and use it for later invasions, producing your own Tyrannid Hive. [Answer] **This will likely not work with any higher organism** Cockroaches as much as any higher organism from earth is much more dependent on an earth-like biosphere, thus your plan would only work under the assumption of a biosphere similar enough to earth to nourish and shelter your neobiota and these have to be tougher than the local organisms adapted to the eco system. **Viruses** Viruses may have adapted to Earth DNA, but retroviruses are still the most versatile and flexible creatures (lifeforms or organisms would not be correct here) we are currently aware of. If the alien way of saving genetic information is so much different that a cocktail of any virus known on earth (and possibly lab-engineered mutations of these) does not have any effect, no earth-stemming organism would have a chance to survive or reproduce at all, as they probably could not even digest local fauna or flora. [Answer] # An assortment of fungi Fungi do not necessarily need oxygen to live. Some are optionally aerobic, so when they invade an ecosystem and overgrow there, they may compete with the local fauna for oxygen. For air breathers there might be little to no impact, but for water dwellers this will spell doom. The fungi may also grow unchecked and deny light to local flora. Unlike viruses fungi will have no problem adapting to local life. Where there is a substrate for the fungi to feed on, there is a way. Finally, the way fungi grow and spread is a marvel of biology. Some like cordyceps start their life as single celled organisms, which then fuse - yes, fuse - into a single chimeric organism shaped like whatever beast it is that they are feeding on from the inside. Others grow to gigantic proportions - [a single individual armillaria is over five kilometers wide!](https://earthsky.org/earth/largest-land-organism-honey-fungus) [Answer] Even if every other aspect of your plan worked (it doesn't, see the other answers), your last step would probably still fail. I'm talking about this "kill switch" you installed. The problem are random mutations. In the best case scenario you have somehow colonized 100 billion star systems within less than 100 thousand years (assumes you spread at light speed starting from one edge of the milky way). For every colonized star system you will have a billion or so cockroaches. So your kill switch must have a reliability of better than 1:100 trillion over 100 thousand years. Those are really long odds. All it potentially takes is one small enough population to survive the kill switch on some backwater star system and who knows what will happen... [Answer] One might suppose the emperor knows where the target planets are. Otherwise, the logistics wouldn't work out without the probes like Kyyshak mentioned. If the hostile civilization is more familiar with the target, it could be possible to engineer the offensive species for each target before sending them. In that case, viruses are still the best bet. Larger organisms might seriously disrupt an ecosystem, but they are unlikely to completely overwhelm local life forms. If you insist on larger organisms, I recommend a duplicate of the target species. These duplicates can be designed with reproductive advantages, breed with the population and spread the kill gene in the target species. [Answer] A cocktail of retrovirus' and bacteria. Have several hundred strains of virus' that are programmed chlorophyll producing cells, bacteria, algae ect. The bacteria are programmed to consume any and all biological material it can. Pretty much go for the bottom of the food chain. These are also programmed to a very quick life cycle, multiplies quickly and adapts to any environment possible. And programmed after a set amount of time to target itself and/or turn off it replication ability. This cocktail would be designed to consume oxygen and eliminate oxygen producers. Soon, much of the complex life would die out, leaving little to stand up against the Empire. This is followed by another cocktail that is designed to restore the planets atmosphere and clean up anything left behind from the first wave. Maybe have a third wave to ensure a clean reset of the biosphere. This wont kill all life, but would make it significantly easier to colonize as there is no mega fauna to deal with, except the ones you bring with you to repopulate. If, as others have mentioned, that the adaptation of your biological genocide bugs gets out of had or fails to perform, drop an asteroid on the planet and say "screw it." ]
[Question] [ First things first: english is my second language, so I apologize in advance for every mistake. In a game of mine (D&D 5e) I've created a world, Eos, with a sentient race for each god. There are N gods, and I've managed to link each classical race to each power. Just for reference, the other races are: humans (goddess of solidarity), hoflin (halfling, god of freedom), dwarves (god of wit), orcs (goddess of earth), "tiefling" (god of fire and shadows), elves (goddess of magic), wylde (god/goddess of the moon and the sun). There are several sub-races and also several cultures. The influence of each god on its "children" is more physical than cultural. And then there are the *pahilam*, the race created by the goddess of war and violence. And I'm stuck. I think that they are a bit dull. They look like humans with red skin and red-purple hair. Their bodies are much stronger and tough and they can easily use their bare hands as lethal weapons. Their skin is hard to pierce. They are quick, and they can also survive for several days without eating or drinking. And that's it. From a mechanical side, they are a good race: they can do what a low level monk can do, and they are toughter than most of the other races. From a cultural point of view they are mainly part of a large empire, but there are also other factions. I've already outlined their rules and traditions. My real problem concerns their "fluff". So the orcs has their tusks, and a complex honor system; the elves can adapt to every habitat, slowly changing their bodies; the wylde are twins that can create physical body doubles; the hoflins are mildly psychic, etc. But the pahilam are mostly strong humans with red skin. What can I do to make them more unique? I'm stuck. **EDIT** To be clear, I don't want others to work this for me. I'm sorry if this is not clear in my question, but I'm looking for something that could be of inspiration for this race. Their main culture is set, and I've got no problem with that. It was easy. What I don't know is how to make them unique lorewise. For example, in D&D kobolds are well known for traps, cowardice and small size; drow are generally evil (I know, I know), troglobes with a penchant for spiders; and so on. I'm looking for some advice on *how* to make a race more interesting and less boring. **EDIT II** Thank you everyone for your answers. I need to rewrite the question to be more clear. It's hard because in my head I know what I'm talking about, but I can't pull out the worlds in english. I'll think about a way to be more clear and on point. [Answer] **Ancient Grome** [![enter image description here](https://i.stack.imgur.com/yzTYe.jpg)](https://i.stack.imgur.com/yzTYe.jpg) She is the god of war. Not the god of battle. War is about logistics. War is about discipline. The Pahlim have ancient Greece/Rome inspired fluff. They have the largest and most technologically developed civilization in the world. They have large cities, extensive trade routes, sharply defined borders, well-drilled army battalions, marble arches, aqueducts, and a senate full of pompous officials. They have the best technology. They have concrete. They have uniform stone blocks for their buildings. They have a uniform measurement system. They are the only civilization in the world that produces paper in bulk. However they are bad at magic. Usually the role of Lawful Neutral civilization falls to the Dwarfs. But I see your world does not have dwarfs so the spot is open. Their culture revolves around following the law, creating order and society, doing right by your inferiors, obeying your superiors, and maintaining one's own reputation. The Pahlim might or might not have slaves, depending on if they are the goodies or the baddies. Since they are lawful they have strict regulations for how slaves are treated. How much food and rest they get and how you may punish them. Like the Orcs they have a sense of honour. Unlike the Orcs their honour does not come from single glorious acts. Their honour comes from keeping your word and contributing to society. You are not supposed to distinguish yourself since no one individual is greater than the society as a whole. Their heroes are not famous warriors. Their heroes are shrewd politicians and generals. These guys make wise decisions within the scope of the law. One type of adventure you can have in Ancient Grome is political intrigue. [Answer] ## How to Create a Race from a High Concept Start off with the high concept. You've done this part already, it is **war**. The next step is to ask yourself what qualities represent those who are built for this high concept. Don't just name one, but name all of the qualities you can think of. Next, start thinking of powers that could represent those qualities. An ideal power will represent not just one, but several of those qualities. For example, a god of war is about more than just violence: they could be about control, protection, tactics, organization, etc. So, instead of just giving them the obvious power of strength, figure out what powers could represent these other qualities. Once you have multiple possible powers for each race, you want to filter through them for cases where there is overlap to make sure you're races are not being assigned the same powers to ensure each is unique. So, if one power fits 2 or 3 races well, then choosing the Next Best Fits may be better just to add diversity to your system. Lastly, once you have powers assigned to each race, you need to refine them such that they are balanced. Sometimes you have a power that is useful for so many things, that you need to limit when it can be used, or nerf its power, or vise versa, you may have powers that are so niche, that you may need to expand on it, or even give a race more than one power to balance it out. ### Possible powers could include: **Domination:** the ability to control others through supernatural intimidation or mind control giving Pahilam war chiefs the ability to raise armies out of any population. The represents the control and organization aspects of war. **Foresight/Danger Sense**: The ability to intuitively make good tactical choices by predicting what they need to do/not do for a better strategical advantage. This represents the protection and tactics aspects of war. **Synergy:** War is won by soldiers, not heroes. Pahilam may simply become overall tougher when working in cooperation with others so, some kind of party buff based power system would work. This could represent the might, protection, tactics, and organization aspects of war making this an especially representative power for your Pahilam. However, since your humans represent the divine aspect of "solidarity", you may find that Synergy is a better power for humans, and choose a slightly worse fit in favor of diversity. Or you could limit how the two races synergize so that maybe Pahilam get synergy buffs that are specifically useful to combat, whereas humans may get synergy buffs that are more specific to out-of-combat or mental challenges. [Answer] **Teracotta Warriors** [![enter image description here](https://i.stack.imgur.com/YunZl.jpg)](https://i.stack.imgur.com/YunZl.jpg) The reason the Pahlim are so strong and tough is they are not made of meat like the other races. They are constructed for war out of river clay. That is why they are so tough. It is also why they are red. It is also why they have different hair colors. The hair does not grow, it is attached to the head as a decoration. In battle they style their hair into different colored crests to denote rank. Like this: [![enter image description here](https://i.stack.imgur.com/QCq6G.png)](https://i.stack.imgur.com/QCq6G.png) The Pahlim do not have organs. If you chop off an arm it hurts, and they cannot use that arm anymore. But they will not bleed to death. The Pahlim do not give birth. They construct new ones of themselves. The Pahlim do not have children. They are "born" as adults. [Answer] # Gender Predominance: You have a race honoring a goddess, centered on war. I agree that war is about logistics, but you want this to be biological. So let's do something unique. Your race are all born female (honoring and in the image of the goddess). By legend, they may claim their whole species is descended from her. They are capable of giving birth [parthenogenically](https://en.wikipedia.org/wiki/Parthenogenesis), so even one individual can repopulate if needed. It also means that with almost every individual being female, the population can VERY rapidly expand or replace losses. After all, just about everyone can give birth. Extremely successful warriors are given the honor of becoming "consorts to the goddess." HOW this happens can be up to you - an actual divine blessing, game level, or some kind of vote among warriors. Like some species of fish, they can undergo a developmental change known as [sequential hermaphroditism](https://news.yale.edu/2009/02/02/why-don-t-more-animals-change-their-sex) and turn into males. They can then engage in sexual reproduction, spreading their "strong warrior" genes throughout the population. If you make them quick to develop into adulthood, their potential to build large armies extremely quickly would be frightening. # A little bit reptile? Parthenogenesis is found in lizards, so this works even better if your race has reptilian qualities. If, for example, they are tough because of scales, or do more damage because of claws. It's not uncommon for reptiles to be able to alter their metabolism to tolerate deprivation. In that case, I'd have them lay eggs, leaving their offspring to gestate in military academies back home, seen over by the elderly and maimed. Producing new warriors then becomes an almost industrial process like the training programs of ancient Sparta. You might then want them a bit more equatorial, though, as they might slow down in cold weather (a built-in weakness?). You might want to look at [Neith](https://en.wikipedia.org/wiki/Neith), an early Egyptian goddess of war, for inspiration. She could give birth parthenogenically, suckled crocodiles, and sometimes appeared as a snake in her role of protecting dead warriors. For the violence part, [Tiamat](https://en.wikipedia.org/wiki/Tiamat) (the Mesopotamian Goddess, not the 5-headed dragon, although they are related) was a goddess of creation and chaos, who gave birth to the dragons to create an army with which to fight the gods after they killed her mate. Her body was used to make the world, so she can symbolically be a goddess of parthenogenic birth and death as well. In that case, your warriors might consider themselves the kindred of dragons. [Answer] This may be something of a 'frame challenge' answer, because most other responses have associated 'war' with armies, and organized militaries. Armies exist even in peacetime. It could even be said that most organized military units exist in peacetime as a *deterrent* against wartime. (How effective those deterrents are is debatable, but that's beyond the scope of this answer.) That isn't what 'war' actually is, though. War is the destruction, death, starvation, terror, and defiling of innocent bystanders. War is the extreme of violence. War is indiscriminate. Nations and their soldiers may well attempt to limit or *tame*, war, but in the end the bomb doesn't care whether the person caught in its blast is a soldier, a doctor, or even an infant. War consumes whatever it touches. Think about what *that* means for a species created by a goddess of war and violence. Your goddess of war and violence may well be better known to people as the goddess of monsters. [Answer] **Borrow the Tengu** [![tengu](https://i.stack.imgur.com/fobykm.jpg)](https://i.stack.imgur.com/fobykm.jpg) <https://www.deviantart.com/flying-fox/art/Tengu-113998170> Flying Fox your Tengu rocks hard! Bird people are not Tolkien or Game of Thrones. They are a cool idea that has not quite been done to tiny bits. I like the idea that the big ones cannot fly anymore but they can jump 10 meters using their wings. Kids can still fly. When the bird people go to war, they all go to war. Watching your 6 is not enough. The idea that the tengu might be associated with war is congruent with their role on folklore. <https://en.wikipedia.org/wiki/Tengu#Martial_arts> > > During the 14th century, the tengu began to trouble the world outside > of the Buddhist clergy, and like their ominous ancestors the tiāngǒu, > the tengu became creatures associated with war.[41] Legends eventually > ascribed to them great knowledge in the art of skilled combat. > > > [Answer] # Myrmidons The [Myrmidons](https://en.wikipedia.org/wiki/Myrmidons) are, at least in Ovid's telling, more about hard work and thriftiness than war. Nonetheless there is some variety in the tradition, which seems like it might have originated with some early contact between simple people and armored soldiers, just as Centaurs might have been a description of mounted soldiers. Perhaps you can make your *pahilam* a social race, bred from one or a few queens in a colony, serving as comrades, fiercely territorial and warlike against their own kind and all others. They might physically resemble ants about as much as the original *"The Fly"* resembled his insect forebear, with hard exoskeletons, compound eyes and mandibles and such, and various advantages and disadvantages you might lay out accordingly. [Answer] ## A (sort of a) hive mind A hive mind or group mind is when multiple entities have their minds conected into one single consciousness. If we talk about war, this is very useful to organize and synchronize entire batallions. So with this in mind (pun intended) the goddess gave them the capability to achieve this. But! althought its something everyone has, they have to develop it. Some of them (depending on certain aspects) are prone to develop a higher level of group consciousness (let's call it "groupness"). Pahliman can only be "interconnected" with other pahliman that have either similar or lower level of groupness in a way that you can feel and communicate with others on your same level, but are only able to "receive" information from pahliman with a higher groupness; this is what leads to both social and militar hierarchy: a group of soldiers is connected among themselves, and a lieutenant is connected to both one group of soldiers and other liutenants, whom on their own are connected to generals and so on and so forth. This trait is both physical and cultural, as the pahliman have to train and work hard to increase their level of groupness, and of course pahliman with higher groupness are more respected amongst society. [Answer] The question needs work but it is still good. I would recommend thinking outside their main trait (war) and asking yourself some questions like What is their national sport or entertainment? If your answer is something like "they don't have time for sports, they want war" or "Their sport is gladiator arenas" you will end up with a flat race. And even without making it violent you could still tie them to their war traits. Maybe chess (due to the strategic nature of war) or the Olympic sports (many are tied to war). Following that as an example here are some questions that may help: How is their culinary? What are some of their social scandals? What was their biggest political crisis? What are some of their holidays? Try adding a "not related to war" at the end of them. They can have holidays and scandals related to war, but to get the creativity flowing try to focus on the ones that are not related to it, because these questions won't make a race less flat because they now have sports and food, but they will shape how you see them and give you more ideas on what to add to them. [Answer] It sounds like you think gods are important, and perhaps a focus of the story. Cool. One way to make your races less boring is to perhaps not make all of them monotheistic. One race could be based on a single god, one could be from a group of gods working together, one could be from a (differently-sized) group of gods who don't work together. [Answer] **Make them tragic** Make them mature very rapidly but only live for 15 years. By having such short lives, there will be less of a taboo of dying in battle as you don't risk losing another 60 years of life, just 2 years before your genetics fail. Three ways to highlight a short life: 1. Have their bodies (and blood) start off as pure red in color but as they get older both get more and more black blotches - and when they die of old age their bodies are completely black and withered looking. Thus the more red you are when you die (younger) the more life you have stolen from your pointless fate. 2. Make them gifted in mental arts such as philosophy, math and architecture but they literally don't live long enough to do anything with that potential. 3. Short lives means that a slight against a grandfather quickly becomes a slight against an ancient ancestor. Unlike long lived civilizations, you don't have time to make amends for insults you made to the short lived creatures - and so your insults get embedded into their cultural understanding of the world before you can rectify them. [Answer] This race could have a kind of vampiric quality to them. They feed on some sort of metaphysical energy, lifeforce or whatever you want to call it, when they damage or kill their enemies. They heal themselves based on the amount of damage and pain they cause to their enemies. Perhaps they could even need this energy to sustain their life. So this race has to wage war constantly or they die. Mechanically I suppose that would mean buffs based on damage dealt. [Answer] As a source of inspiration, you can have a look at **Zergs** [![enter image description here](https://i.stack.imgur.com/wEUYt.jpg)](https://i.stack.imgur.com/wEUYt.jpg) They are strong, adapt very well to very different environments and seem to only care about destroying and devouring everything. They seem to incarnate all ideas that we associate with War. Your God of War would be very pleased by them! ]
[Question] [ This question is inspired by the [Would high fertility rate among the rich crowd out commoners?](https://worldbuilding.stackexchange.com/questions/86008/would-high-fertility-rate-among-the-rich-crowd-out-commoners) . The tax rate presented doesn't seem to encourage the desired behavior. The starting assumptions are: * The country is developed and wants to promote natality among the well-off using the tax system. * The citizens are not able to avoid paying taxes, without emigrating and renouncing their citizenship. * The government is ready to sacrifice the economic growth for *social engineering* purposes. The citizens who don't want (many) children should work less or leave the country. * The government won't pay any subsidies. Parents should raise their children on their own income. What kind of a tax system would encourage upper income people to have many children? [Answer] **Give tax breaks for having kids as a reduction of your tax rate.** Say an income tax rate is 50% - 5% per kid. A person making 1 million a year makes 50k per kid, a person making 10 million is incentivized with half a million a year per kid. Lower incomes don't care nearly as much. Or divide income by the number of people in the family. A person alone pays tax on all income, with a partner that pay half that, with 8 kids they pay 1/10th. **Encourage polygamy.** Say by making property tax a main tax and exempt a property per woman with children, possibly allowing a bigger property the more kids she has. To afford many expensive properties a rich man must have many wives and a horde of children. **Limit maximum income.** Say a person may only take home a million a year, but allow money to be counted as being earned by a person's children. For some value of the income cap this will not even be subsidies, but an increase on rich people who don't adopt the workaround. [Answer] Your fictional country could: * Make *all* expenses from raising kids tax deductible, and have the amount deducted from payable taxes, not from taxable income, so rich people get 100% of those costs back. * In return for this, stop subsizing schools and kindergartens. Make them finance themselves via fees. Rich people can deduct the fees from their taxes, of course. * Tax childless adults for being childless. Call it *making sure there is an working population a generation from now*, and punish "freeloaders" who don't raise that generation. [Answer] 1. Rich ladies often don't want to bear many children. It is physically arduous, and many of these ladies are rich because they themselves work. If you want your country to be full of the genetic descendants of rich people, use surrogates. Carrying a baby to term is work like any other and women can and do accept pay for this. If the government does not want to be involved except through the tax code, then make the entire cost of the surrogate deductible from income. It is a deduction poor people will not use and so it will only help the rich who are interested in having more children this way. 2. Adoption is another way to get more children into rich families (if you do not care about genotype, only about upbringing). Adoption is expensive and cumbersome. Leave it expensive, so that it is a path available only to the rich. Then as with surrogacy, make all costs deductible from income. 3. Rich people often rear their children with nannies and the like. The rich people spend much of their own time staying rich. Make the expenses of child rearing (like nannies) deductable from income. 4. 100% income tax bracket. This would be for the top bracket, of course. High earners must find deductions from income to avoid being in that 100% bracket. Aside from the deductions above for child costs one could have a standard deduction which is not per child but which increases as the number of children increase. Additionally, the standard deduction (as done on US taxes) is a flat amount. If there deduction were 1% off the income tax rate per child this would be worth much more to the rich than to the poor. One could have a floor below which income tax rate goes no lower such that the rich would still pay some tax - maybe 20%. This would also ensure that people who already play 20% or less do not benefit and so are not also encouraged to have children. The end result of this will be large stables of children putatively of wealthy persons. These children will be raised by employees and may or may not have contact with their parents. This is an existing mode for wealthy persons to deal with their children, and it would just be scaled up for tax reasons. Should someone pursuing this route suddenly suffer a financial calamity he or she might suddenly find the huge loads of kids very financially burdensome. There would need to be insurance such that the government or other interested entity could take over the maintenance of the children and also facilitate their transfer to persons still rich enough to benefit from them. [Answer] Short of a tax that could turn the well-off into not well-off, nothing. It should not be surprising that the rich buy the lifestyle they want, and if they don't **want** a lot of kids, they will pay whatever it takes to avoid that. That is the case with most of them: They have a lot of money, they do **not** want to be absentee parents, but they also do not want to be weighed down and prevented from traveling, entertainment, projects and such by having to care for six kids. They want their child-bearing to be a few kids close together, so their "parenting" time is a relatively short decade, after which kids are in school. Rich mothers do not want what having a lot of kids does to their bodies; and does to their social life and available hours and career: Especially mothers that are independently rich through a career of their own, like those in entertainment, law, real estate or business. They have a busy life, and more than a few years away is all they can afford. Rich fathers are often the same. They want to love their kids and spend time with them, but they are busy staying rich. What you would be encouraging, by forcing them to have kids or lose fortunes, is absentee parents, multiple classes of kids: he first two they wanted and love, and the other six they had through surrogates to avoid millions in taxes, that will be raised by nannies without really knowing their parents, because this was more cost effective than paying the taxes. If it doesn't cost them more than the surrogate-and-nanny solution: they will just pay it, people earning a million a year can get by just as well on \$900K, they will just start donating to an opposition party that promises to repeal the tax you imposed. Or if that is impossible, find ways to hide their income using overseas companies, shells, trusts, etc. --- ### added: Because much of being rich is about power and lifestyle, both of which they can financially engineer by being **in charge** of money, corporations and property that they do not **technically** own. For example, they can transfer their wealth to a Trust for their kids; which they are in charge of until they die (no matter how old the children get). The trust owns the house, the stock, the companies, the cars and planes and boats; and because they are in charge of it, the Trust lets them do whatever they want with those things. They can also buy whatever they wish, they are just doing it on behalf of the Trust. Technically they are not rich, they don't own a thing and earn no salary. The Trust can also own all the stock in a company, and since the guy that formed the trust decides how the Trust votes, he votes himself as the CEO every year. If he wants, he can pay himself some modest salary or bonuses, like $250K a year, not exactly rich, just pocket money for Vegas. Even their credit cards can be in the name of the Trust; which (like a corporation) they can make an independent "person" in the law. So even when somebody **sues** them and wins, if they are suing the person instead of the trust, the person is a pauper and they get nothing. And if American law gets in the way, there are other countries perfectly willing to accommodate them with bullet proof financial protections. They just need to know where to look. [Answer] You would need the change the culture, so that the wealthy want more children, rather than simply having more because its forced on them. People have families because they want some children. Being rich gives you the option to have as many children as you want, and no government scheme will make them *want* more (though it may make them have more in order to maximise their assets). Many will conclude that it might be cheaper to fight or change the government, or leave for a friendlier nation, than to give in to punitive taxation that forces them to do things they don't want to do. The way to get around this is to make it cool or necessary to have large families; maybe emphasise the idea of clans or family-run corporations or a pride in one's lineage (reviving the idea of the noble classes). Maybe there is some shadowy organisation in the background that kills off the children of the wealthy, giving them an incentive to have more (though the rich will almost certainly try to take out this organisation). One issue with this as a concept is that the more children the wealthy have, the more their wealth is diluted amongst the children they do have, making this a self-defeating idea in the long term. Assuming that this downside is acceptable to the government, a lesser issue is that the rich women will want to pass on their genes as well as rich men, but many wouldn't want to spend a significant part of their lives pregnant or nursing babies. An entirely new class of bonded surrogacy services, would arise from this. [Answer] Bring back feudalism and mix it with corporate capitalism. In medieval times, the most wealthy people (nobles) always tried to have many children, because they needed an heir to continue ruling their realm after their death. Children were also needed for political marriages. Also, they needed some children in reserve in case your heir apparent dies. In our modern world, we would have to make some adjustments to this system. Titles of nobility do not count for much. But there is something else in our modern world which we could make hereditary: Companies. Decree that company ownership can not be sold. It can only be inherited or gifted to ones children. When an owner dies and there are no heirs, the company is liquidated and the proceeds go to the government. In our modern world, the risk of losing your only child to the bubonic plague is rather low. But there is a risk which is almost as bad: a child might turn out to be incompetent. So a successful business owner might want to have multiple children to make sure at least one turns out to be capable of not running their company into the ground immediately. This of course requires that the company owner can choose which child inherits which companies (splitting a company is of course always an option a company owner might or might not consider). That means company owners have a strong incentive to have children to continue their company. Investors, employees and business partners will get nervous when an aging company owner is childless, because they know the company will go belly up when they die or become incapable. You could further increase this pressure if you have certain conditions which force company owners to suddenly "abdicate" their position to one of their children. For example if they are convicted for any form of corporate misdeeds: *"The company you work for failed the last OSHA inspection. Your boss is prohibited from leading any companies for a year. What, she has no kids to take over for the time being? Not even a toddler you could make owner in-name-only while the middle managers keep the company running? Well, then the company unfortunately needs to be liquidated and you are out of a job."* A company where the owner has many well-educated children will seem much more secure and future-proof. Another reason to have children in this system: What do you do if you want to merge your company with the company of someone else? You marry into it! 1. You gift your company to your daughter 2. The owner of the other company gifts their company to his son 3. Your daughter and his son get married and have some kids 4. They gift their companies to their most qualified child 5. The child merge the companies 6. (optional) your daughter gets a divorce so she can be used to repeat the process with some other company The problem with this process is that it takes at least two generations. But it might be possible to speed it up with some legal tricks. For example, you might make it possible to *formally* give a company to a child but *de-facto* still retain full control over it. So you can gift a company to your infant grandson, but only under the condition that you keep managing it for them. [Answer] Taxes are not the answer at a first order level, although tax policy can be harnessed to influence more important first order influences on fertility. The biggest drivers of total fertility rates and age of child bearing are the risk of losing a child and the risk of dying before you can have more children. People systemically overestimate both of these risks and over respond by increasing their fertility and age of reproduction than they would if these risks were not present. For example, gang members in places where gang membership is deadly have children early and often, leading to high total fertility rates even though their children are almost certain to grow up in poverty. The same is true of countries with extreme levels of infant mortality and privation like Afghanistan and the poorest countries in sub-Saharan Africa. So, the first order response ought to be to require or otherwise encourage the affluent and their children to serve on the front lines of all military conflicts and in other dangerous jobs so as to maximize the risk of losing a child or dying early. While poverty due to having to support more children does discourage child bearing and tax policy can make a minor tweak to this, it is by far a second order effect. Still, perhaps there is a way to achieve the goal of higher risk with tax policy. This would be to enact huge tax breaks (perhaps total tax exemptions) for military veterans who earn military valor awards, and for members of other high risk civilian professions (e.g. CDC hot zone responders) who are similarly recognized. Since these tax breaks are much more useful to the affluent or for people who expect to be affluent, than they are for the average person, these tax incentives might disproportionately lure affluent people into these high risk posts, and these high levels of risk, in turn, might do their magic of enhancing total fertility rates among the affluent people who take these risks. [Answer] If you want your rich people to have more children, limit the amount of money which they can leave to each child. If each child can inherit no more than one million dollars in cash, assets and possessions combined and if I have built a twenty million dollars fortune from my inheritence,... I'm going to sire kids like a bunny rabbit, just to keep the bureaucrats from getting my hard earned money when I die. [Answer] From the POV of tax policy, in broad terms there's one way to incentivise rich people to do X while avoiding incentivising poor people to do X. That's to provide a tax break for doing X which poor people find themselves unable to claim. It seems to me that you cannot simply reward all child-related expenditure, because poor people spend a significant proportion of their income directly on their children and therefore would be incentivised too. We don't want to give poor parents any kind of break, right, only rich parents? So if a rich parent is spending 10% of their income on their child, and a poor parent is spending 30% of their income on their child, you make that deductible from tax, then that's still a huge incentive to the poor person even though the dollar amount for them is less. Similarly, the other question you link to that inspired this one is still giving a lot of incentive to poor people to have children, because dropping from 40% to 10% marginal rate is pretty huge. So, provide reductions of taxes that rich people pay and poor people (entirely or mostly) don't. For example the top rate of income tax, capital gains tax, property taxes on the most valuable property. Since X is children, costs related to live-in nannies or private education could be made tax-deductible, but not for food or clothing. At least, not ordinary food or clothing. To really drive the point home that you hate poor people, set a threshold at which the benefits kick in. For example if you spend at least Y amount of money on X (your own children), including childcare and education and maybe money paid into trust funds and whatnot, then you get the benefit. Less than Y, none of it kicks in. Then choose Y to be roughly an amount that rich people with children are spending on their children already, and poor people don't have available to spend. Finally, the number of children needs to be taken explicitly into account in the tax system, otherwise there's nothing to encourage a rich person to have 8 children, as opposed to just spending 8 times the money on one child. Of course all these things are pretty blatant, so don't expect the policy to provide a covert nudge. You've won election on a "more rich kids" manifesto, right? > > * The citizens who don't want (many) children should work less or leave the country. > > > I assume you mean *rich* citiens who don't want children. I don't think there's any way for a tax system to drive people out of the country other than by overtly punitive taxation. Really you should look more to criminal law to do this *effectively*: simply arrest those who should have children but don't, and they'll start fleeing if they can. But that's not the premise of the question. So, if you really want this, then set the top rate of income tax and capital gains tax at 90% (or heck, 120%, but arguably once you're past 100% it's not even tax policy any more, it's just a fine for wrongful behaviour). Reduce it per child. But do bear in mind that rich people find ways to ensure that their income is not legally classed as income, so it's genuinely quite difficult to place taxes in places that catch them. One innovative suggestion for catching the rich is to tax property instead of income. Since you're willing to sacrifice the economic well-being of the country, many of the usual objections to it fall. Then ensure that rich people provide an honest evaluation of their property by giving them a straightforward tax return: they say one number representing their opinion of the total value of everything they own, and they don't need to provide any justification for that number. The government then has a choice between accepting some percentage of that number as that person's tax for the year, or else purchasing from that person everything they own in return for the number they said. Of course this would lead to a rapid uptake of crypto-currency, Swiss bank accounts, buried treasure, and other assets that cannot readily be confiscated. But you've already stipulated that in your world, tax avoidance is somehow difficult, so I will hand-wave that away by assuming this government somehow polices such things. Applying this to the encouragement of children: "some percentage of that number" will depend on the number of children. To ensure that it only incentivises the rich to have children and not the poor, then again you make sure that this tax regime only applies to rich people: people with minimal discernable assets and whose main income is a job with a salary below a certain amount continue paying income tax as before, while the rich are moved to property tax. Of course, this really only works if rich people broadly support your goals, agree with you that they all ought to be having more children, and enthusiastically set about having them to avoid the penalties for not doing so. Otherwise you've just *seriously* upset all the rich people, in which case they won't emigrate, they'll have you assassinated. Deposed if you're lucky. [Answer] You ask about using **Tax System** to increase **birth rate** from **well-off (rich)** family. The difficulty here is that is target population THE RICH, not THE POOR. Therefore, we have to make some rule that can only benefit the rich. **Tax deduction: (@o.m. idea)** everything you pay for children (health care, education, ... ) is count as tax. For example, the family have to pay `$1000` tax a month. They have a child. They send their son to a school cost `$700` a year. When the family pay tax, they only pay `$300` (they already 'pay' `$700` in children education) *My opinion:* It still benefit the poor, but not very much because they cannot get `$700` off their tax for their son because they do not have `$700` in the first place. They can get `$100` off, however. The proposal still benefit a middle class a lot, who have just enough money to invest in their kid. The very rich does not care much about this. **More tax for childless:** Who does not have child will pay more tax. Each children they have, they pay less tax. My opinion: this is not going to work. It hurt the poor. Because, if you have children, you cannot raise it, but when you don't, you have to pay more tax. It might work if combine with **Tax deduction** The rich doesn't care because they can 'paid' for their lifestyles. **Tax thresholds for privileges**: Tax thresholds is use to measure how RICH the family is. If family pay tax above the thresholds (for example, more than `$1000` a month), their children can access to public school. More, then better public school. And healthcare, bus, flight, etc ... It is depend on how the government want to social engineering, they can give a list of threshold (targeting) and following privileges. Note that the privileges can not only for children, but for their parent as well. For example: A minister chair only for those who pay `$10000` tax (max sure he is well-off class) and have 3 kids. *An example I just think of:* ``` `$1000:` public school (increase birth rate among middle and upper class but reduce those from lower class) `$5000:` one of best public school in nation (Harvard or Yale for example). This allow you to create a group of best citizen from rich family. `$10000:` and 3 child: Can become Minister of ... (increase birth rate among those rich politician) `$x0000:` and x child: Have royal title (?!) `$x00000:` and x child: Can have y private plane (more children = more plane :3 ) ``` [Answer] To make the *rich* do something is very difficult. The simple answer is this: For tax paid ***over one million per year***, **each child** you have eliminates **one quarter** of your taxes. (Note too that, especially, the system *includes* death taxes) # They'd call it the "25% kid" rule... So to be clear - 1. For ordinary poor people (ie, people who pay under $1m a year in tax), the law does nothing. They are not affected in any way. 2. For rich people (those who pay more then $1m a year in tax), the saving is incredible, stupendous. Say you're paying 10 million a year tax. All you have to do, is have four children ............... and *you now pay basically **no** tax!!* (You only pay the modest baseline $1m a year.) For the profoundly rich who pay 100s of millions a year in tax, it would be insane to not have four children: every single truly rich person would have four children: it would be absolutely ridiculous to not do so. As mentioned above - especially - death taxes are the truly hated thing amongst the rich. Consider tycoons with a wealth measured in the billions. When they die, basically the government takes most of it. By simply having four children, they get to *keep ALL of their money* (ie, the inheritors get it all, the government gets nothing). The above system would certainly and absolutely ensure that everyone who pays more than, say, about $2m a year in tax, would, almost certainly have four children - it would be crazy not to. --- Note that one huge social effect would be: women who *want to have* many children would be in incredible demand amongst the super-rich. (Indeed, it would apply to men too: imagine a super-wealthy family and consider one of the females in that family. It would be totally ridiculous if she married a man who "only wanted one or two kids" - you'd be literally throwing away billions.) Almost certainly women (and men) would start having children very, very young (why risk billions of dollars on an older partner - fertility declines with age, there is chance of not being able to have the four children, when one starts older). One plot point could be .... perhaps women would tend to have one "demonstrator" child at a young age, I mean to say as a single mother, at say 16. They would then be really "proven" (i.e. to the world's rich) that they can easily bear healthy children. Conversely older men with lower fertility, would be summarily discarded by the world's female rich: there'd be no room for niceties in the need to quickly reach four children. Don't forget, for the truly rich you'd be throwing away 100s of millions a year, **until you got to** the "four quarters"; every year you waited until getting the four children would be more zillions down the drain; it's possible very young marriages would become the norm again (as for all of history before about 100 years ago). --- [Answer] Scale inheritance taxes based on how thinly the estate is spread. This would come with two components: Number of people, and similarity in size between their shares. Both would reduce the amount of tax the government charges. For similarity in size, the smallest share pays nothing, larger ones pay 50% tax. For example, \$5 billion split \$3b for one and \$2b to the other, would result in after-tax inheritances of \$1.5b and \$2b, respectively. For number of people, the starting rate could be 50%, and it halves for every two people. Leave your estate to one or two heirs, and 50% goes to the tax office. Leave it to four, and only 25% gets taken. Leave it to six, and it's down to 12.5%, and so on. To disincentivise them leaving it to a company or charity instead of their kids, those bequests are taxed even more heavily, say 75%. If you want to ensure as much of your fortune stays in the family, you have a lot of kids, leave equal amounts to each of them, and leave it directly to them, without using company or charity intermediates. [Answer] Extremely high transfer taxes on spending/withdrawing (simpler to make withdrawing money near illegal) money for expenses, moving your money out the country, corporate fringe benefits, corporate money transfer for anyone above your target income then you exempt everything related to childcare and household including the personnel and their fringe benefits- as long as you have put the worst sharks of your tax department to police this plus extremely legal reform so they can't get past this. Then special tax exemption bodies for this siblings so the money they receive is actually worth something. Why have any exemptions for non-citizens/emigrants? This sort of heavy taxation is going to have an effect- it will do the social engineering. Transfer taxes are impossible to get past with a modern banking system as it in the financial institutions/property registers. Hideous taxes on holding cash and possibly basically support (like they basically can't insure against such robbery- a tax on that) for criminals to rob them. [Answer] First have a regressive (fixed amount) flat-tax per year per child, something like $15,000. That reflects the government's cost in education and healthcare. Then have a progressive (percentage) tax deduction or credit per year per child, e.g. your taxable gross income is reduced by 10% per child. Reducing your AGI 10% reduces your taxes by more than 10% if the tax system is bracketed or curved. Say also that an ordinary family typically takes \$10k/year of other deductions (standard deduction and all that). The \$15k/kid/year is also tax deductible since governments don't tax **tax**. ``` Income 0 kids tax 3 kids tax extra kept income per kid $40k 4k 40k (all) -12k $100k 22k 46k -8k $1M 400k 300k 33k $10M 5M 3.5M 500k ``` **For the very rich: the proportions stay about like this**, letting them keep 5 more % of their income per kid. --- Gory details **You make \$40k/year**, no kids. Minus the \$10k, you're in a 15% bracket so paying ~$4000 in tax. You make \$40k/year, 3 kids. You are underwater because your $45k 3-kid tax > your income. **Make \$100k/year**, 0 kids. Taxable income is \$90k/year putting you in a 30% bracket, tax is ~22,000 figuring for the curve. You keep $78,000. Make \$100k/year, 3 kids. Taxable income is 30% less (-\$30k) - the 10k standard - the \$45k tax you pay, or \$15k. That's in a 10% bracket so \$1500. Total tax is \$46,500, you keep $53,500, or about what an American nets after also paying state tax, FICA, healthcare and higher education. **Make \$1M/year**, 0 kids. You're in a 45% tax bracket, so \$400,000ish tax, you keep \$600k. Make \$1M/year, 3 kids. Deduct \$10k, \$300,000 for the 3 kids, and the \$45,000 kid tax you paid, giving \$645,000 taxable income. Taxed at 45%, about \$255,000. With the kid tax that's \$300k, so \$700k you keep. **You're being paid $100k to raise 3 kids.** **Make \$10M/year**, 0 kids. Taxable income is \$9.990M, putting you in a 50% bracket for almost all of it. Tax is \$5,000,000, you keep \$5,000,000. Make \$10M/year, 3 kids. Deductions are the 10k standard, 30% (\$3M) for the kids, and the \$45,000 tax you paid for the kids. That's \$3,055,000. Net income is \$7M, back in the 50% bracket so \$3.5M. Add the \$45,000 kid tax you paid, tax is $3.545M, you keep \$6.455M. **You are literally being paid \$1.455M to have kids.** Make \$10M/year, 9 kids. Deductions are 10k, 90% (9M) for 9 kids, and $135,000 kid tax you paid. That's \$9,145,000, leaving \$855,000 taxable at 45% or ~\$370,000 plus the kid tax. You keep \$9.5 million. You are literally being paid \$4.5M to have 9 kids. ]
[Question] [ After seeing that recent pistol (<https://en.wikipedia.org/wiki/FN_Five-seven>) has bullet diameter quite similar to one used in modern assault rifle, I started to wonder whether it is possible (and reasonable), to design: * pistol and assault rifle of the same bullet diameter, but different ammo length AND * both pistol and rifle are of reasonable performance AND * just in case of running out of rifle ammo, one can load inferior and shorter pistol ammo in to rifle. (without caring any special converting gear) **Would such bullet compatibility be possible without any serious trade offs?** (I'm not asking about using the exactly same bullet, but ammo of DIFFERENT length) [Answer] ### Same width projectile > > pistol and assault rifle of the same bullet diameter, but different ammo length > > > Absolutely. An [M-16](https://en.wikipedia.org/wiki/M16_rifle) is a .22 caliber, as are several pistols. Note that this isn't what you actually want. There is no indication that any existing pistol can actually fire an M-16 bullet or that any existing pistol bullet would go into an M-16. ### Different length ammunition in the same gun See [this](http://www.webyshops.com/tech-talk/how-to/22-Ammunition-Basic-Info.html) for example: > > ### .22 Short > > > The .22 short was originally developed as a self-defense round in the 1800s, and while you'll see it primarily used in smaller handguns today, you can still find rifles capable of shooting both short and long .22 rounds. However, it is important to note that .22 short rounds fired out of rifles tend to be less accurate than .22 long rounds. 22 short rounds are always rimfire, and contain relatively light powder loads vs. other .22 ammo. If you're planning on stocking up on .22 short rounds, best do it for your .22 handgun, and leave your rifle round purchases to the more reliable .22 long rifle. > > > The .22 short mentioned here is suggested as being mostly for pistols but usable in some rifles, albeit with lower accuracy than ammunition better designed for that rifle. Note that this is purely single shot rifles that are bolt action. ### Interchangeable ammunition There are several examples of rifles and pistols that can share ammunition at [this page](http://www.gunsandammo.com/network-topics/the-guns-network/11-great-pistol-caliber-carbines/), e.g.: > > **Rock River Arms LAR-9 CAR A4**: This handy, reliable AR is user-friendly and tons of fun to shoot. It comes with a 16 inch Chrome Moly barrel with a 1:10 twist rate, optional R4 or RRA Quad Rail. The six-position tactical CAR stock from RRA is easy to use and locks securely in place, and the gun comes with an A2 flash hider with ½-36 threads. Hogue grips offer a secure, comfortable hold, and the excellent single-stage trigger makes this one of the most accurate 9mm ARs available today. The flattop forged upper offers plenty of space for mounting any optic you’d like, and at just over seven pounds, this is a very comfortable rifle to shoot, even for extended periods at the range. RRA offers a wide variety of options and upgrades, and the CAR A4 is a very good defensive firearm. It’s also loads of fun to shoot. MSRP: $1,180. > > > Perfect Partner Handgun: There are few things more fun than sharing a few boxes of 9mm ammo between your RRA CAR A4 and H&K’s new VP9 at the range. > > > This is a fully automatic rifle, although some of the other examples are single shot rifles. There is an argument that *any* rifle that uses pistol ammunition is technically called a sub-machine gun. This rifle differs from the typical sub-machine gun in that it has the long barrel and stock of a rifle. It's unclear to me if the technical difference between an assault rifle and a sub-machine gun matters for your story. You may want to be careful to avoid the term "assault rifle" unless you are willing to explain why you think that it is appropriate. This is interchangeable ammunition, not ammunition of different lengths. The tradeoff here is that the rifle would *always* use the pistol ammunition. So its flight characteristics would match a really long barreled pistol rather than a target rifle. Of course, the kind of ammunition that an assault rifle (e.g. the M-16) uses is also a compromise. It's a smaller projectile and ammunition than used by battle rifles like the M-14. And the M-14 and other contemporary battle rifles used a shorter ammunition than the original Browning Automatic Rifle or the M1 Garand. Smaller and shorter means lighter. Lighter can be easier to carry, more rounds for the weight, or a combination of both. The argument against using pistol ammunition is that it is shorter but still heavier. So if we take 210 rounds of M-16 ammunition as the typical amount a soldier carries, you might find that it would change to 150 or 160 rounds instead. And not fly farther or hit harder than the pistol. Only a bit more accurately, particularly at longer distances. ### Different length with an automatic There are no examples of this. Different length ammunition is used with single shot rifles. Interchangeable ammunition is the same length for both. My quick guess as to the problem making the different lengths work in an automatic is that it would jam more often. It's adding more complexity to the rifle. It might actually be easier to reverse things, making a special handgun designed to fire rifle ammunition. It's unclear how useful that would be compared to a rifle with a long and short barrel combined with a removable stock. [Answer] > > *pistol and assault rifle of the same bullet diameter, but different ammo length...just in case of running out of rifle ammo, one can load inferior and shorter pistol ammo in to rifle. (without caring any special converting gear)* > > > Before going into the technical details, let's discuss why you wouldn't bother. # Pistols Are Not Useful On The Battlefield Hollywood has given us an extremely exaggerated idea of what a pistol can do. A pistol is a personal defense weapon with an effective range of about 20 meters with moderate training, 30 if you practice. In any scenario where you're concerned about running out of ammunition, a carbine (ie. short barrelled rifle) is superior in almost every way except maybe weight. Pistols are inaccurate, underpowered, and have a low capacity. A pistol has a very short barrel which cannot take full advantage of a higher power round, nor make it accurate. It has a low capacity 7 to 15 round magazine. The lack of a stock makes it difficult to steady, especially for follow up shots. Its short length means the rear sight and front post are too close together for accurate shooting. In contrast a [carbine](https://en.wikipedia.org/wiki/Carbine#Modern_history) has a longer barrel, generally has a full 20 to 30 round magazine, a stock to steady your aim, and the longer length provides more distance between the rear sight and front post to make aiming easier. # Ballistic Coefficient Then there's the ammunition. Pistol ammo not only has less gunpowder, it usually has a smaller, lighter projectile than the equivalent caliber rifle round. This is bad news for accuracy, range, and stopping power. The [ballistic coefficient](https://en.wikipedia.org/wiki/Ballistic_coefficient) is a measure of how well a bullet can overcome air resistance. A higher number means less drag which means it takes longer to slow down. $$BC = \frac{mass}{diameter^2 \* i}$$ As you can see, the more mass the better it will slice through the air. For example, the FN Five-Seven fires [5.7x28](https://en.wikipedia.org/wiki/FN_5.7%C3%9728mm), a 2 gram projectile at only 700 m/s. It starts slow, and slows down fast. In contrast [5.56x45 NATO](https://en.wikipedia.org/wiki/5.56%C3%9745mm_NATO), an intermediate round of nearly equal diameter, fires a 4 gram bullet at 900 m/s. It starts faster, and it can retain that velocity better. There's little reason you'd want to carry a ton of pistol ammo. Instead, you'd carry a bunch of intermediate ammo, like [5.56x45 NATO](https://en.wikipedia.org/wiki/5.56%C3%9745mm_NATO) and maybe a pistol and a few pistol magazines as a backup weapon in case your rifle jams or is lost. # Practical Alternatives Firearms designers struggled with the gap between pistols and rifle rounds for about 100 years, and they've solved it pretty well in the last 50 by introducing intermediate cartridges like 5.56 NATO. The major realization was most combat happens inside 300 meters and a full power rifle round that can go out to 2000 meters was overpowered. This allowed the creation of smaller, lighter, shorter rifles with less recoil and more firepower that are plenty accurate. For special cases, you have a [designated marksman](https://en.wikipedia.org/wiki/Designated_marksman). This is why, for example, the [M1 Carbine](https://en.wikipedia.org/wiki/M1_carbine) replaced the [M1911 pistol](https://en.wikipedia.org/wiki/M1911) or [M1 Garand](https://en.wikipedia.org/wiki/M1_garand) as the primary weapon for support personal in WWII. The M1 Garand was too big and heavy to be lugged around when it's not likely to be used. A .45 pistol is too inaccurate and only has 8 rounds. Currently the US military is in the process of [replacing the M16 rifle with the M4 carbine](http://www.thefirearmblog.com/blog/2015/07/29/marine-corps-brass-approve-replacing-m16-with-m4-carbine/); same basic rifle, same round, but one's a lighter, shorter carbine. You'd either carry a carbine which fires an intermediate round, like the [M4 carbine](https://en.wikipedia.org/wiki/M4_carbine). Or use a pistol-caliber carbine like the [Kel-Tec SUB-2000](https://en.wikipedia.org/wiki/Kel-Tec_SUB-2000) or [Beretta Cx4 Storm](https://en.wikipedia.org/wiki/Beretta_Cx4_Storm) which gives you the benefit of a longer barrel, stock, larger magazine, and longer sight picture. Another alternative is to use a rifle like the ubiquitous [AR-15](https://en.wikipedia.org/wiki/ArmaLite_AR-15) that is amenable to conversion in the field. The AR-15 can be pulled apart without any tools, and you can swap out various parts to accept various calibers. This does mean you'll have to carry a different upper receiver, bolt, barrel, spring buffer, and maybe even trigger group, and you'll have to re-zero the rifle to the new bullet. Not something you want to do in the middle of a fight, but not something you need an armorer for either. I just can't see any situation where, in the middle of a firefight, you suddenly find yourself with an overabundance of pistol ammo and no rifle ammo. Probably your best bet is to use a single round, the FN 5.7mm, and carry both the FN Five-Seven pistol, and the [FN P90 submachine gun](https://en.wikipedia.org/wiki/FN_P90). As you'll see below, the 5.7mm round is somewhere between a pistol and rifle round. Fired out of the longer barrel of the P90, it has a reasonable range and accuracy, and a 50 round magazine. [![enter image description here](https://i.stack.imgur.com/I0h8g.jpg)](https://i.stack.imgur.com/I0h8g.jpg) [*Source.*](https://en.wikipedia.org/wiki/FN_P90#/media/File:FN-P90_2.jpg) Fans of the Stargate TV shows will recognize the P90 immediately. The downside is FN 5.7 isn't a terribly popular round. While it is a NATO standard, it isn't used by much more than the Five-Seven and P90. If you're concerned about ammunition supply, go with something everyone is using. That will depend on where you are. --- # Caliber is the Diameter of the Projectile, not the Cartridge! There's a common misconception that, for example, a 5.7mm round means the cartridge is 5.7mm. That's not true. For example, 5.56x45 NATO is 9.60mm in diameter at its widest; only the bullet, the tip of lead that actually fires, is 5.56mm (really 5.7mm, don't trust bullet names). FN 5.7x28mm isn't 5.7mm either, it's 7.9mm at the base. [![enter image description here](https://i.stack.imgur.com/8hGQz.jpg)](https://i.stack.imgur.com/8hGQz.jpg) [*Source.*](https://en.wikipedia.org/wiki/FN_5.7%C3%9728mm#/media/File:Many_bullets.jpg) Left to right: 9x19mm, .40 S&W, .45 ACP, ***FN 5.7x28mm, 5.56x45mm NATO***, .300 Winchester, 70 and 76mm 12 gauge shotgun shells. Note how very different in size 5.56 NATO and FN 5.7 are. # Cartridge and Bullet Geometry Note that the bullets have a different geometry. The pistol cartridges are very short and cylindrical. This allows them to pack the most powder into the shortest possible space, something you want in a pistol which has to be compact. They fire a fat, flat nosed projectile. It isn't very aerodynamic, but pistols are inherently inaccurate; what happens after 50 meters doesn't really matter. It's all about making up for their relatively low velocity by throwing as much mass down range as possible. Rifles don't have to worry as much about space, but they do have to worry about range and accuracy. They use a longer, larger diameter case to pack in as much powder as possible. Then it gets "necked down" to a smaller bullet diameter. This also helps feeding the longer cartridge by giving it a little ramp. A smaller, longer, pointed bullet has better aerodynamics and can fly further, faster, and flatter. These are known as ([Spitzer bullets](https://en.wikipedia.org/wiki/Spitzer_(bullet))) introduced around 1900. FN 5.7x28mm is somewhere in between. It's like a tiny rifle round, and that's what makes it so versatile. Compared to the 9x19mm, the ubiquitous 9mm pistol round it was designed to replace, it has far, far less bullet mass, 2g vs 7.5g, but it's fired at almost twice the speed, 715 m/s vs 400 m/s. Since kinetic energy is $mass x velocity^2$, despite being a third the mass both rounds have the same kinetic energy leaving the barrel. But its smaller diameter and aerodynamic shape means the 5.7 has better range and accuracy. So while FN 5.7 might be a good choice if you want to settle on one round for everything, it will swim around in a gun chambered for 5.56 NATO. # Rimmed vs Rimmless Revolver cartridges usually have [a rim around the base significantly larger in diameter than the rest of the round](https://en.wikipedia.org/wiki/Rim_(firearms)#Rimmed). It's this rim that keeps the cartridge from sliding further into the chamber. This is why revolvers can handle cartridges of varying lengths. The downside is it's relatively weak and it's possible to tear the rim off when extracting in a high powered round. Anything fed from a stacked magazine (ie. just about everything in the last 60 to 100 years) uses [a rimless cartridge](https://en.wikipedia.org/wiki/Rim_(firearms)#Rimless). It still has a rim, but it's the same diameter as the case, it doesn't stick out. The chamber is shaped to match the geometry of the cartridge and the cartridge fits snuggly into the chamber with minimal gaps, more on that below. The smooth geometry of the round means it stacks well in a magazine and feeds smoothly out of it, there's no rim to snag. This is why, for example, there's a plethora of "ACP" pistol rounds. ACP stands for [Automatic Colt Pistol](https://en.wikipedia.org/wiki/Automatic_Colt_Pistol). When semi-automatic pistols started appearing around 1900 they needed new, rimless cartridges to work with the new "automatic" magazine fed system. Point is, you can't use a rimmed cartridge in a gun that expects rimless and vice-versa. # Centerfire vs Rimfire Cartridges have a primer, a bit of explosive that will go off with hard whack. The hammer or firing pin strikes the primer which ignites the gunpowder which throws the bullet out of the gun. And, you should not be surprised to find out, there's two different ways this is done. First is [rimfire](https://en.wikipedia.org/wiki/Rimfire_ammunition). That means the primer is around the rim. The hammer or firing pin strikes the rim of the cartridge. They're cheap, but they cannot be reloaded. For this reason, rimfire tends to be used on small cartridges where you're not throwing away a lot of brass. Then there's centerfire which, you guessed it, has the primer in the center. These must be pin fired, but you can have a hammer which strikes the pin as in the Colt 1911. Centerfire is safer, produces a smoother detonation, and the case can be reloaded. Most importantly, they allow for a sturdier base which can withstand the higher pressures of rifle rounds. For this reason, nearly all rifle rounds are centerfire. You can't use a rimfire cartridge in a centerfire gun, and vice-versa. # Bolt Locking and Headspace AFAIK this has never been done, except for very small variations. For example, many rifles can take both [7.62x51mm NATO](https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO) and [.308 Winchester](https://en.wikipedia.org/wiki/.308_Winchester), though there may be malfunctions because of the different powder loads and chamber pressures. The primary problem has to do with the bolt locking mechanism and [headspace](https://en.wikipedia.org/wiki/Headspace_%28firearms%29). Any breech-loading gun (ie. gun for the last 150 years or so) has to have some way to open the breech so a round can be loaded, and then seal it so the round can be fired without high pressure gas leaking out. There are many, many ways to do this, but it usually involves a ["bolt"](https://en.wikipedia.org/wiki/Bolt_(firearms)) which moves back to extract a spent round, and forward to strip a fresh round off the magazine and shove it into the chamber. The bolt is locked in place: rifles usually have a [rotating bolt](https://en.wikipedia.org/wiki/Rotating_bolt) with locking lugs (just like a bolt-action rifle), while pistols usually have a less robust but shorter mechanism based on [recoil](https://en.wikipedia.org/wiki/Recoil_operation). The bolt face is flush against the base of the round. This is both to lock the breech so gas cannot escape backwards, and also because the firing pin is usually in the bolt face. Point is, you can't have a gap between the bolt face and the round, and the bolt must be securely locked. That means the round must be of [a specific length and geometry for that chamber](https://en.wikipedia.org/wiki/Headspace_(firearms)). Too long and the bolt won't lock. Too short and the round won't fit snugly in the chamber, when the round is chambered it might slide too far forward resulting in a gap between the bolt and bullet base that could cause a rupture when the bullet is fired. Or when the firing pin strikes the base the bullet might slide forward resulting in a light strike and the bullet not firing. # Cycling The Action The next problem is getting any semi-automatic gun to reliably cycle with such wildly different powder loads and projectile weights. There's two major ways semi-automatic and automatic weapons are cycled: gas and recoil. Gas uses some of the gas from the exploding gunpowder tapped from a port at the end of the barrel. Recoil uses the recoil force of the projectile. Both work only within a specific range of forces. Gas-operated weapons can *usually* be adjusted by tuning their gas port: how much gas gets vented from the barrel into the mechanism. This adjustment can usually be done in the field with no special tools. Recoil-operated weapons usually require changing the recoil spring. Neither are designed to handle such wildly different amounts of gas and recoil as between a pistol and intermediate cartridge. Instead it's about variations in ammunition quality, environmental conditions, and how well maintained the weapon is. You'd have to make a lot of compromises to have a semi-automatic weapon that would cycle reliably with pistol and intermediate cartridges with just field adjustments. --- In any situation where ammunition supply matters, you're not going to be using a pistol as anything but a backup weapon, so carrying a bunch of pistol ammo doesn't make sense. Go with a carbine instead: it's more accurate, and has a greater magazine capacity. If you really want to be flexible, carry an AR-15 and a conversion kit. Or chuck the conversion kit and use the saved weight to carry more rifle ammo. [Answer] This is all going to depend on your definition of "reasonable". A pistol is normally fired in one hand. This limits its weight to about 2 to 2 1/2 pounds, both in terms of aiming accurately and recoil. An assault rifle is intended to use both hands, and a weight of 6 to 8 pounds is a reasonable number. So, in rough terms you can expect an assault rifle to weigh about 3 times what a pistol does. This in turn suggests that an assault rifle round will have a momentum (mass times muzzle velocity) about 3 times that of a pistol, so an assault rifle which fires a pistol round will be rather underpowered compared to assault rifles which do not. The recoil of a weapon is (to a first approximation) proportional to the mass of the weapon for a given round. Furthermore, since a pistol round will be designed for complete powder combustion within the rather shorter barrel of a pistol, an assault rifle with a normal barrel length will be grossly underutilizing its barrel length, and will be larger and heavier than it needs to be. The thing is, you haven't defined "reasonable". If the issuing military decides that the benefits of a single cartridge outweigh the drawbacks of reduced performance, that is entirely up to them. The P90/FiveseveN combination is a good example. The small caliber permits decent energy at the cost of momentum, so the pistol is adequate. The P90, on the other hand, was intended for use by those not ordinarily in combat, such as vehicle drivers, and at short range. It's been adopted by police-type units, but it's not generally considered powerful enough for front-line troops. The same sort of calculation is likely to recur for any use of a pistol round in the assault rifle role. [Answer] **Probably** It would not be very practical, you could have a weapon with 2 different [bolt carrier group](https://en.wikipedia.org/wiki/Bolt_(firearms)) that could be moved into place like the cylinders in a revolver. Each could accommodate a different length ammunition. The drawback is the weapon may not cycle properly when switching to the lower power pistol rounds if gas or spring operated. Another drawback is the weapon becomes more complex. [Answer] OK, so the problem is using current firearms and brass casings. Go to a caseless design and it would be doable. Why? Most pistol rounds are straight walled cases, with a rim (mostly revolvers) or rimless (mostly automatics). Most rifle ammo are "bottle neck" designs, where the base (with or without rim) and lower half of the casing are a larger diameter, and then they neck down (at various degrees, depending on the round) to the bore diameter. So a traditional pistol round isn't going to work with a traditional bottle neck rifle round. There would be nothing to support the case walls, you'd have case blowouts and all other sorts of kaboom-like experiences. Not good. All that said... Go to an older design, like revolvers and lever action rifles (1860/70s technology) and it already exists, either using same ammo or using the "special" version of magnum pistol calibers - 38 Special and 357 magnum are exact same, but the case length on the 357 is .1" longer. Same with 44 Magnum and 44 Special, several 32 calibers (32 long, 32 h&r magnum, 327 federal), etc. More recently Ruger has made semi-auto and bolt action carbines and rifles in 357 and 44 magnum. Of course, rifles and pistols can be designed to use the same round from the first drawing on... This is the case of the PS90 and FN57 you mention. There are also ARs and AR-like rifles/carbines chambered for pistol rounds, some using the same magazine as a popular pistol in that caliber (Glock, Beretta, etc). You can also create what the US Government defines as a pistol by not putting a full length stock and a shorter barrel on, in a very specific manner (otherwise you end up creating a short barrel rifle, that while cosmetically and functionally identical is a very restricted NFA item and requires a $200 tax stamp, extended back ground check, etc). There are plenty of AR and AK based pistols. Finally lets not forget the various single shot rifles chambered for pistol calibers, and the "specialty" pistols chambered for various bottle neck rifle rounds. Of course, almost all of these are single shots. [Answer] No, because you said *assault rifle*, which implies semi-automatic. For a variety of reasons, but mainly because of [rim lock](http://wethearmed.com/rifles/rim-lock-the-problem-with-rimmed-rifle-cartridges/), almost all practical semi-auto weapons use rimless cartridges. Rimless cartridges [headspace](https://en.wikipedia.org/wiki/Headspace_(firearms)) off the shoulder or neck of the cartridge. So even if length were the only difference between the rifle and pistol cartridges, you'd still need to swap barrels for proper headspace. So while this is technically possible, it wouldn't be very practical. Instead of lugging around an extra barrel on the off chance of needing to fire pistol ammo, a soldier would be better off carrying more primary ammo. This might actually be practical if you weren't asking about semi-automatic rifles. There are carbines that fire pistol ammo, and the primary ammo for the rifle could be loaded hotter than normal pistol ammo. (Although then you would have to be careful not to accidentally load the rifle ammo in a pistol.) You could also have a bolt action rifle that fires straight-walled rimmed cartridges (which headspace off the rim) and can fire shorter pistol cartridges without modification. There would be no risk of loading the rifle cartridges into a pistol. [Answer] Not really as you have phrased the question. By definition assault rifles use high velocity but small calibre rounds. The rational being to give a weapon which can provide effective and accurate fire over moderate distances (say about 300m) but still retain good accuracy and handling characteristics at close quarters and in confined spaces. By contrast pistols and sub machine guns tend to use large calibre, low velocity rounds which provide good accuracy and handling at short range but rapidly drop off as range increases. There is also the fact that pistols and rifles tend to use a different operating mechanisms. Most pistol calibre weapons operate by blow-back where the force reaction force of the cartridge on the bolt pushes the bolt backwards and cycles the action whereas automatic rifles tend to use a gas piston arrangement. There is also the consideration that pistol calibre rounds are now seen as increasingly less viable as military weapons, except as lightweight secondary sidearms, partly due to the proliferation of body armour which is very effective against pistol rounds. What is increasingly common is a radically shortened version of the standard infantry assault rifle, for example the L22 carbine version of the L85A2 used by the British Army and issued to aircraft and vehicle crews. There are also a number of purpose built weapons with a SMG type barrel length but assault rifle ammunition type. Equally short barrel assault rifles are generally superior to SMGs in performance with very few drawbacks and having the advantage of reducing the number of different ammunition types required. Even specialist units which like counter terrorist units of police and military which retained SMGs much longer than regular infantry have now mostly switched to some form of assault rifle chambered for an intermediate round. If anything the trend in the military has been to go back to larger rounds in the 7-8mm range for increased effectiveness at longer ranges, especially in light of experience in the Middle East. Similarly the only real logic for carrying pistol ammunition is in very limited quantity for a secondary weapon which you would probably only use if your primary weapon was lost or inoperable. [Answer] Possible? Yes Doable? Yes Better idea? Of course. Use the same magazines that will fit the gun and rifle. But for the quick answer: Rock River Arms LAR-9 CAR A4 and KH VP9 CMMG Mk9 T and CZ P-09 You probably noticed the number 9 is reappearing. It's 9mm. Those wacky germans in the XIX century figured out it would be cool if the same bullet would fit in the carbine, gun and revolver. Oh, and if the gun could be easily converted into a carbine (hence the Mauser broom). When you consider using shorter ammo for the pistol in your rifle remember that this is actually useless from a logistic point of view. Yeah, the ammo crates carry more ammunition with pistol ammunition, but they also weigh more. And it's better to stock and carry better ammo. So, from a soldiers point of view it's better to have 3 magazines for their rifle on them than 4 magazines for their pistol. [Answer] For your information: Hi-Point firearms makes both a pistol and a carbine that not only fire the same round but also share the same magazine, available in .40, .45 and 9mm. American made, lifetime warranty and affordable. ]
[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/58508/edit). Closed 7 years ago. [Improve this question](/posts/58508/edit) What if the human race never sedentarized and was forced to wander on earth. What if a creature hunted humans restlessly and the only way to survive was to avoid settling down for more than 48 hours. And i mean, a creature Humans could never surpass or hide from, no matter what technology level they reach. They are hunting all over the world, maybe thanks to species variation. (I won't hide you don't need to ask what they are, they are just a reason to prevent Human from settling. And all humanity is threaten, all civilizations of this world would be vagrants. How much effort would it take to reach a Middle Age level of civilization and what would it look like ? By "Middle Age level of civilization" i mean the evolution gap between firsts homo sapiens and Middle Age civilization. It is ill posed, but it's hard to quantify. It's like saying the Lord of the ring take place in Middle Age, it's wrong but it still light up images in our mind. And, i don't want answers like "It's not a plausible world" or "they'r all going to die anyway", It's a fantasy world so i just need plausible way for humanity to survive and achieve technology and knowledge to go as far as Middle Age level. [Answer] **Don't sell human brains or natural selection short.** We are incredibly adaptable to varying conditions and there's no reason to assume we would be unable to thrive in the conditions you're describing. You need to think in terms of what kind of realistic **abilities** and **technologies** these people would have. For example, they might be fantastically good at multitasking--they walk and weave at the same time. They have looms that attach to their bodies so they can weave while they walk. They carry vats for paper making harnessed to themselves. You have the vat on your back and the person behind you is stirring it while you are both walking. Children pick up weaving and other crafts really quickly because the genes that govern that are selected. Navigation is second nature to everyone. Maybe they don't have to write because they have extremely good memories. Suppose someone came up with an incredibly effective mnemonic device system that would be roughly equivalent in their society to the printing press. A way to describe their developed technologies in extremely efficient verbal shorthand. Maybe they have litters where they can carry young/sick/old. Maybe the litters are really expansive and carried by everyone--say it's mounted on your shoulders and head so the people under the litter are still free to use their hands. Maybe people could sleep in shifts and you could never need to stop at all. Maybe genes would be selected in such a way that you got a mix of diurnal and nocturnal people so that you had natural 24 hour "coverage". Domesticate something that can travel at the same pace as you. Herds of elephants that hold up a litter that has a small village or garden on it. Suppose you had a few dozen vegetable gardens widely spread out. You tend each for a few hours of the day as you pass by that way. Suppose you randomize the order in which you visit them so that the predator doesn't figure out how to use your schedule to track you. This vegetable garden idea could have naturally come up by someone having the idea to plant the seed of something they ate in a place where the nomadic travels would bring them back, and when that worked everyone started doing it every place. "The world is our garden/farm". Instead of having a place with a fence and a home, you cultivate everywhere. Multiple highly cooperative groups doing the "cultivate everywhere" thing, just seeing what needs to be done in a given field and doing it and moving on, since, if everyone does that, the food will be ready at the place you happen to be when it's harvest time. (Mormon pioneers did something like this--the first group to leave would plant a field that a later group would harvest when they got there.) Maybe people don't have time to fight each other, so they are genetically selected to be cooperative rather than violent. Extreme cultural bias toward cooperation. Permanent structures could be built a little at a time so that eventually there are little clusters of shelters all over the place. That could give you a motivation for writing since they could leave notes to each other about local needs or resources. Maybe you would have different cultures evolve that did different combinations of the above. Like some have the gardens and some have the elephant-mounted platforms and some do the human-mounted litters. Big structures like bridges could be built cooperatively over time. Instructions could be left saying "we did X, the next thing that needs to happen is Y, there are trees at Z location that would work for that". Maybe you have a specialization called a "runner" that moves between groups carry messages/warnings/etc. Maybe you could have "homing dogs" or something where instead of just messages (like homing pigeons would carry) they can have a pack tied to them and they are released and know to find their way back to their return point. Domesticated birds that live in a mobile chicken coop and provide eggs. Some kind of plant/berry/whatever that is cultivated and selected to need small amounts of soil so that it could be carried with you and provide you nourishment. [Answer] # The Mongols were "vagrants" - even as a large empire Let's step back a bit: the ice age warms up and humans are able to domesticate plants and animals and use agriculture as a means to make food instead of hunting and gathering. The vast majority of humans across the earth become agriculturists. However, a fair number - particularly in the vast steppes of Central Asia - become herders. Herders are an interesting and viable alternative to agriculture. Instead of settling down and growing crops, herders got a bunch of animals that could provide meat, milk, hides, and so on, and traveled around with them as they grazed. This made things like developing systems of laws somewhat difficult, as there was no "capital city" among herders, but individually, herders have historically been **MUCH** hardier than agriculturalists. Onto the Mongols. In the early 13th century, a bright and charismatic Mongol leader named Temujin gets the idea to unite all the Mongol tribes. Long story short, it works out. He becomes known as the Great Khan - Genghis Khan. Then Temujin/Genghis Khan realizes that the powerful Chinese state to the south would never tolerate an equally powerful neighbor, so he takes the fight to them by going **around** the Great Wall of China and interrogating Chinese prisoners of war along the way to learn about siege warfare. They besiege the Chinese capital and crush the Jin dynasty to create the Yuan dynasty and the Mongols begin their rule over China. Another long story short, they send an emissary to Persia to open trade. China and Persia have never been on quite good terms over their claims on Central Asia, so the Persians behead the emissary and return the head to China. Genghis Khan is furious and has the Mongols conquer Persia as well. At that point, he pretty much decides that his role in life is to unite the world under Mongol rule. Longer story short, Genghis Khan and his descendants conquer half of the known world, from Russia to Korea to the Middle East and so on. Sounds pretty hellish, right? Not really. Life under the Mongols was actually pretty sweet. You could do whatever your local lords permitted and the Mongols hardly cared as long as it didn't get in the way of trade, which they taxed. They were also pretty brutal, as you could imagine, and so highwaymen all but disappeared under their domain. It was said you could carry a golden plate above your head from one corner of the Mongol Empire to the other without being accosted even once. As for the Mongols themselves, they were content to live outside cities in their yurts and carry on their herding ways, as long as you paid taxes. They were also shamanists (where gods were tied to specific lands), so there was complete religious freedom in the Mongol Empire, which is actually quite rare among history's empires. So to answer your question, the Mongols - for the span of their empire, at least (until the USSR forced them to settle) - never really "evolved" from a "vagrant" civilization. Herding worked well for them personally and as long as you paid your taxes the Mongols ruled with quite a light touch. They moved people like administrators and engineers wherever they were needed because the Mongols themselves didn't care for that kind of thing, but they valued people that could do what the Mongols could not. In that case, this hypothetical "middle ages" level of civilization wouldn't even need to be established by the ruling empire. I know this contradicts the idea of a human-hunting monster in the original question, but I hope I could help illustrate an alternative form of society that served its people well. [Answer] # We would most likely have died out What are you are saying is that the genus [Homo](https://en.wikipedia.org/wiki/Homo) of the Earth would have forever been [hunter-gatherers](https://en.wikipedia.org/wiki/Hunter-gatherer) and also been forced to remain nomadic. This in turn means that the [Neolithic Revolution](https://en.wikipedia.org/wiki/Neolithic_Revolution) would never have taken place. Without the Neolithic Revolution, it is unlikely that we would ever have evolved — biologically and socially — to the point where we are today. And whenever we were hit by calamities, such as extreme seasons leading to food shortage, we would have been decimated (as did happen). So in all likelihood we, as Homo Sapiens, would most likely have joined our other Homo cousins and died out too. [Answer] # We would have found a way to wipe the predators out Over the past 45,000, we (as a species) have systematically wiped out any major species we've come across - either as a food resource or to compete for resources. This may be intentionally, as a consequence of us wiping out the natural prey for this super-predator, or from climate change (humans adapt to climate change more readily than other larger animals). Given our natural desire to kill things, it was inevitable that we'd create enough of a dominance over the environment to settle. The other alternative is that this super-predator would have wiped out any proto-human species before it had a chance to evolve. [Answer] **Some Stone Age people were already very nomadic**. Many years ago I had a conversation with Dr Erik Trinkaus in which he told me that the leg bones of ice age humans from Europe & the Near East were very well developed. From the size of muscles which would have been attached to those bones, Trinkaus estimated those ice age people were walking an average of 20km a day. He also said that he'd never seen a skeleton with a leg broken badly enough to be unable to walk. If you couldn't keep up, you were abandoned by the group. The injury that lots of the people DID have was repetitive strain injuries to the hands and wrists from dragging heavy objects - probably dragging animal skins with heavy-ish stuff on them, like small children, tents, meat and so on. However, that 20km is an average. The people could and did stay in one place for a while. If the salmon are running, you stay by the river and catch fish. If the reindeer are migrating, you ambush a bunch of them and spend several days butchering your kills, drying the meat, starting to tan the hides, and so on. If there is a blizzard raging, you stay put in shelter or you die. **What applies to the humans also applies to the predator**. If the humans can't stay put for more than 48 hours, then neither can the predator. Unless it is a Terminator with a fusion plant powering it or some sort of Hollywood movie monster which ignores all laws of biology or physics, the predator will have to do all the things that lions, tigers and bears do - mate, raise young, spend time eating its kill. If it is not dedicating enough time to that, it will die out. If its babies can't keep up or be carried, it will have to stop following people to care for them. And if the babies are vulnerable in any way - say it lays eggs and abandons them - the humans will murder those babies all to death as soon as they figure it out. **The predators can't follow every group, all the time.** 100 humans are being followed by 2 predators. If they split into 3 groups, one of those groups does not have a predator following it! **The humans cannot have any technology which requires significant time and effort to produce the end product.** They can't make pottery, smelt metal, weave cloth, tan leather, or even bake bread (those loaves need to prove overnight, and grinding grain into flour takes ages). They'd probably even lose some technology which those ice age people mentioned above have - no time to mine for the best flint or heat the flint nodules in a fire to make them into more workable stone. No time for cave paintings. No time to tan leather to a decent standard which will last a long time. Humans are almost reduced to a chimpanzee level of technology. [Answer] **NOMADS** You would see societies of nomads like many that are still around today, though it would depend on the nature of the elements preventing people from settling. **Population Size and Communication** Technological development would be dependent of the population size, the pressure to develop, and how much communication there is between humans. The Inuits, as a great example, have some wonderfully sophisticated means for surviving. I've heard their clothing compared to an astronaut's. **Socializing** Even if the nomads wander about a bit, and can't settle (for long), it's likely they'll run into humans from time to time, have regular meet ups in a general area, develop some signalling systems to help them find each other. They'll then be able to trade commodities and technology, celebrate, marry, and perhaps war. This does depend both on how warlike other humans are, and what kind of threat is preventing them from settling. **Threat** If the threat is intelligent, signalling and meeting up will get harder. If it is constant, then humans may be ran too ragged to survive or develop under the constant pressure. The right amount of pressure will accelerate development, too much will destroy it. Humans could be expected to learn the ins and outs of this threat, if they can survive long enough. **Conclusion, and Mobility** How long it will take to get to middle ages tech is unfortunately too hard to say without knowing the above details. It will also be fairly random as to when (many developments are based on coincidence). Some items of middle age tech, like large furnaces, would not be possible to move around with a nomadic group. You could have stationary furnaces/facilities that a group revisits periodically to make use of. Otherwise, they'll be technologically stuck on processes which you can carry with you or finish in a short span of time (however long they can settle). Hope this was helpful to you. [Answer] # Part I: Humans would migrate and settle Humans are remarkably adaptable to radically different environments; most other large animals aren't. We would instinctively or even incidentally take advantage of that. Ravenous tropical/subtropical predator that relentlessly hunts humans? Nomadic populations would migrate towards the poles, settling in freezing arctic climates. Dressing themselves in thick hides and furs, and hunting lesser arctic wildlife, humans would soon adapt to an arctic way of life, while the bone-chilling cold would deter any significant incursion. Polar bears on steroids? The reverse would happen; humans would move into dense tropical jungles and arid desert areas where the creature's fur and fat that enable its survival in arctic regions would rapidly exhaust and kill it. Humans would wear minimal clothing and develop lightweight and portable shelters; in arid climates water would become a commodity. Vicious jungle beasts? As with the bears, humans would find arid climates to their liking. Storage of water and development of temporary/portable shelters would allow them to adapt, while the unavailability of water would swiftly dehydrate the (likely high metabolism) predator. The only advantage it might have here is if it discovers that humans have water skins, and swiftly tracks from settlement to settlement, tearing into their water supplies after attacking to rehydrate. # Part II: Humans would kill the predator Once humans settled in a climate hostile to the predator, they would have time to start developing more advanced tools (including activities such as mining and smelting, to start producing metals)... and sooner or later their collective interests would turn towards killing the predator. I would be entirely unsurprised if unrelated settlements (which would naturally evolve into villages and then cities over the course of generations) start getting the same idea in different geographic locations, and then begin fighting back, squeezing the predator population from multiple sides until it eventually collapses. Thanks to communications skills, storytelling, and eventually the written word, humans would definitely hold a grudge against this one animal they cannot dominate or domesticate, and as technological advancements bought them more free time they would devote that time to conquering the beast. Between the human ability for strategization and group tactics, and development of specialized hunting tools and traps, sooner or later it would find itself on the losing end of the dominance order. # Part IIIa: The predator would go extinct Due to the long and antagonistic relationship between humans and this super-predator, once humans developed the technology and strategy to fight back, they would likely make concentrated pushes against it, focusing on destroying nests/killing young. Initially it'd just be to reduce the thread posed, but once we securely have the upper hand there's no reason to leave it to chance, and we'd continue pushing until it posed no threat any more. At best, if we've evolved socially and technologically far enough by this point, we might keep a few specimens captive in zoos, and the beast would live on in stories told to keep little children in line. ### OR... # Part IIIb: Humans would domesticate it Humans like to put animals to use. Whether raising them for food, transportation, or other utility -- even sport, humans have a long and rather successful history of domesticating animals. As soon as they finished with Part I, they would probably start domesticating lesser animals, and eventually some industrious humans would get the bright idea to start domesticating the super-predator. Some cultures might domesticate it for sport, pitting them against one another. Others would domesticate it for defense or war, unleashing them on the enemy to cause major casualties or at least serious distractions. Still others might train it as a hunting animal -- if it were successful enough at hunting resourceful humans, it no doubt has attributes well suited for hunting. Repurposing these hunting and tracking skills to exterminate lesser threats (wolves, coyotes, and others that interfere with domestic livestock), counter greater threats (any wild super-predators still surviving), or hunting wild prey (tracking and perhaps chasing big game) could prove very useful to advancing human civilizations. [Answer] Given the base assumption that the Ancestors, Neanderthal and Denisovans are not at the top of the food chain but apparently are still human level intelligence, you are setting up a condition where Homo Sapiens will begin to evolve into something else. Indeed there could be several "something elses" developing because of the evolutionary pressures being exerted on the Hominids. Looking at how some of our other cousins deal with similar situations, some Hominids might develop a social structure similar to Baboons, where up to 80% of the young males interpose themselves between a marauding leopard and the rest of the troop. Hominids using this strategy will experience some pretty extreme dimorphism, as young males become much larger and more aggressive in order to successfully defend the troop. Going the other way, Hominids stuck in environments like the Great Plains or Steppe might evolve to become more fecund, in order to have enough members survive to adulthood. These Hominids will have litters of babies, short gestation periods and young which can rapidly become self sufficient. It is a fair guess the tradeoff will be energy intensive adaptation like intelligence will be dropped in favour of instinct and more rapid development. Finally, the Ancestors themselves might be able to establish themselves in relatively secure environments, either so harsh that the predators are unlikely to follow (Tundra, high arctic, deep deserts) or defendable redoubts (mountains or areas ringed by mountains, islands) where they have a much better chance of seeing, isolating and killing predators, and keeping areas clear. There is a possibility that the selection here is going to be for greater intelligence, so teams of hunters will be able to successfully patrol their areas, communicate better and design and build better tools to deal with the predatory species. Once again, there will be some selective pressures due to environment (Ancestors living for generations in the high arctic will come to resemble the modern Inuit people, for example), and if the period of isolation is long enough, the Ancestors themselves will no longer be able to interbreed, so creating multiple species of Humans. [Answer] My source for this answer is the excellent [Guns, Germs, and Steel](https://en.wikipedia.org/wiki/Guns,_Germs,_and_Steel). # How do we reach "Middle Ages level"? The foundation of a Middle Ages society (and really, any society beyond hunter-gatherer levels) is *surplus*. Each peasant farmer produces more than he needs to feed himself, allowing a permanent class of bureaucrats (lords, priests) and specialists (soldiers, craftsmen) to exist. Without bureaucrats, you can't have large scale organization (beyond 150 people). Without specialists, you lack technological advances, conquest, etc. How is the farmer able to generate this surplus? The answer is *crops*. Domesticated agriculture produces a ton of food, and that food can be stored easily in granaries. What's more, this food can be generated reliably - a hunter-gatherer might go out to hunt deer and come back at the end of the day having caught zero deer. The farmer's wheat, on the other hand, won't run away from him. # How do we acquire surplus without crops? Many societies practiced a hybrid of hunter-gathering and farming - when they migrated through a promising area they took care of the plants (by clearing out the small ones and weeds and making room for the big plants to grow) and when they migrated through that area later in the season, they collected the fruits of their labour. But this only works for a relatively small tribe. Your civilization needs *animal husbandry*. Horses are super-useful both as sources of meat, and as a way to move your junk around and stay ahead of the predators. Cows, pigs, chickens, and camelids are also useful as mobile sources of meat and muscle. These animals are also a great way of transforming your garbage into food. Even dogs are edible, and they help you hunt on top of that. Your civilization may also need to resort to cannibalism if they cannot acquire enough of these animals - why waste a perfectly good dead body? Disease is a far-off concern if you die of hunger otherwise. But this is not enough. The Mongols are an example of a nomadic society that was very successful, but they were able to survive by skimming off settled, feudal societies. Your people will have nothing to raid and pillage, no palaces to sack, no granaries to loot. Dependent on gathering for any kind of vegetables, your people will have a very strict population cap, and their societies will never be as large as medieval ones. # Forget about the bronze age Ever tried to load a smithy onto a wagon? Even if your people could gather metal ores from surface deposits, they would not have great facilities for processing it. Your metal tools would be rare and rubbish. Wood, leather, stone, and bone would dominate. [Answer] **We farm and work in loop groups** We need to grow food to have a large surplus of food to allow for civilization. We have to move every 48 hours and can't return in the near future (at least a few weeks). If it is safe for others to be in these areas then our crops that are left unguarded they will be eaten and destroyed either by animals or other humans. We will evolve to have rotating groups. Say we can't return for 4 weeks (then we need 14 sites) we stay and work and farm at a site for 48 hours then move to the next one. If the reason we move is because the old site becomes unsafe, we just leave it and assume our crops will not be touched by other humans, we just come back and get them 4 weeks later. Perhaps hiding or fencing off our food and tools to protect them. If the area is safe for other humans just not us then we split the tribe into 14 groups. Each works and guards a site for 2 days and then moves on to the next one. That way all sites are guarded at all times The cycle avoids us having to carry all our possessions with us and still lets agriculture and construction develop. We would develop a huge sense of trust since most or our possessions are guarded by someone else most of the time. [Answer] Without a technological basis, your "humanity" would crumble. First, consider that even nomadic civilization have more time to settle than your requirement, and most of those lived at least partly as scavenger or raider upon settled civilization. A question, first : are you talking about a single civilization or the whole humanity ? From what you wrote, I'll talk about the first case. European and Asian middle age technology would be impossible as you can't mine for ore. In fact metal would be impossible to obtain and work with. You need a bit more than 36 hours (plus sleep) to discover metalworking or any important craftsmanship. But that's the least of your worries, some civilization did well without metal... until they met people with steel weapons. Your problem is two fold : * Death rate at birth would be huge : human female are not supposed to give birth then ran around chased by a predator attracted to the smell of blood. Not much would give birth more than... once. And babies are not supposed to be shaken in a frantic run in the minutes that follow their birth. Also, the permanent stress (for both male and female) of predator attack will simply prevent many pregnancy. * You can't have evolved craft without thinking and working calmly for more than 36 hours (because you also need sleeping) **What you need is a partly sedentary humanity that has to give up this aspect** of most civilization for... reasons. Many early discovery, linked to settlement, are mandatory to the survival of humanity. At the bare minimum, with domesticated animals, you can put your pregnant women on a carriage and have them survive pregnancy. With big enough carriage, you can get some kind of craftsmanship that takes more than 36 hours work. Oh, and you shouldn't have a pregnant woman ride on horse back, if you want her to stay pregnant. But you need that sedentary phase or longer resting phases. Maybe there are killer clouds that people have to flee, but those clouds are seasonal ? [Answer] This doesn't directly answer the question, I suppose, but you could look at already imagined cultures that are vagrants/nomadic. Specifically, I'm talking about the quarian race in the Mass Effect series. Physiologically, they've evolved a weak immune system (being forced to live on spacecraft for hundreds of years in clean environments could do that) and depend on biosuits in foreign environments. I think that'd be specific to a space-faring civilization. A nomadic civilization bound to a planet may have the opposite effect; being exposed to a wide variety of pathogens and allergens may cause the species' immune systems to be quite robust. Culturally, they've developed in a way that nomadic cultures would value. They have a 'coming-of-age' tradition where one leaves the Migrant Fleet to search for something of good use to the Fleet (i.e. resources, ships, technology, etc), or must perform acts that would benefit the fleet (i.e. defeating geth, the quarian 'mortal enemy'). They also, as a species, developed an affinity for technology since they are required to build and fix what they need when they need it (especially crucial in the case of an emergency failure of a spaceship). This kind of evolution only occurred because the quarians were at a technological point to have already developed space-faring technology, so it would depend on the situation of your hypothetical species. You should sit down and make a list of questions about what nomadic cultures need, and answer how they'd get them. Like: * What resources do they need? How do they get them? * What cultural traits would be condemned/praised? * What skill traits would be condemned/praised? * Do they have enemies that cause problems? Allies that provide solutions? * If they have enemies that cause problems, how can they solve these problems? This approach will help you build a well developed culture/species for immersive enjoyment. I guess this kind of does answer your question, but definitely check out [the quarian entry on the Mass Effect Wiki](http://masseffect.wikia.com/wiki/Quarian) for a better understanding of that particular nomadic civilization. ]
[Question] [ In my story, the protagonist gets sucked almost a millennia into the past (unintentionally) and lands in medieval Europe. How does he take advantage of the situation and rise to power without getting branded a heretic/demon/devil by the Church and burned at the stake and either executed in some way or imprisoned and exploited? Every scenario I play over in my head where he tries to convince people that he's from the future, or demonstrate his superior knowledge of the universe, he winds up dead or imprisoned. I'm thinking that his best chances for survival are to strip out of his futuristic clothes, hide any tech he might have on him and try to blend in until he can get into a position to seize power somehow. How does he do it? Does he approach the nobility and offer them promises of power and wealth? Does he win the hearts and minds of the poor, secretly empower them with knowledge and improved weapons technology then try to overthrow the church and nobility? What's his best chance of using what he knows of the future to take over the world? [Answer] My advice to your protagonist and any Worldbuilding SE readers who unexpectedly get sucked back in time is (a) *don't* try to convince people you are from the future, not until you are rich and secure anyway, and (b) don't try to publicly take over the world - be content with influencing powerful people from an advisory position, rather than ruling yourself. Another story you might look at was written in 1939 by L Sprague de Camp, [*Lest Darkness Fall*](http://en.wikipedia.org/wiki/Lest_Darkness_Fall). In it an American archeologist is transported from then-contemporary Mussolini's Italy to sixth century Rome. It's hinted that his mind being so fixed on the past is the reason that the time-slip happened, a neat way to explain why he conveniently speaks Latin and has some knowledge of the major military and political figures of 535 AD. If I recall correctly, the first wondrous invention that the hero brings to sixth century Rome is... distillation of spirits. He correctly calculates that brandy is a product from which he can almost immediately start making good money. He keeps his mouth firmly shut on his temporal origins, saying only that he comes from an obscure and faraway country called "America". Later on he introduces Arabic numerals, and the semaphore, but fails to get several other inventions to work, and doesn't get the girl. He keeps from getting condemned as a heretic (*much* more of a danger in late Roman antiquity than in your scenario of this happening in the medieval era) by "smothering his enemies in cream" and giving the most hostile bishops lucrative church offices. [Answer] The only thing that might be possible given the limitations would be to bring the Infantry Revolution early. In most places, fighting men were trained from early boyhood to use weapons, so revolts by the peasants was pretty dangerous (an untrained and unarmoured man with an agricultural tool in his hands can be dangerous, but against trained troops protected by even a small amount of armour, they are generally disadvantaged). The Infantry Revolution was triggered by the appearance of weapons and tactics that could be used by large numbers of relatively poorly trained troops that gave them the advantage over armoured nobility. In Europe this was the introduction of the crossbow (the English Longbow and the Ottoman compound bows required a lifetime of training, while a crossbow could be used fairly effectively after about a day's training), pikes in dense squares and various specialized pole arms which allowed a man to go one on one with a mounted knight and pull him from his horse, skewer him or crack open the armour with the extra leverage (the halberd head allows the user to do all of the above). Of course a rabble armed with these weapons would still be scattered like chaff; the other part of the revolution was to convince people to stay in close ranks (a pike square with a frontage of 10 and a depth of 10 can rapidly manoeuvre around a battlefield) and cooperate (having rows of crossbowmen between the pike squares gives long range protection, while the squares hold off cavalry charges and even oncoming infantry. Groups of halberd armed men between the squares or in reserve can trade off with the crossbows when needed for the close fight, while the crossbowmen fall behind the pikes). How our hero could convince people to do this would be an interesting trick (perhaps the core of the story). I suspect the crossbow would be an easy "sell", since even merchants can see the benefit of being able to effectively arm everyone in the wagon train or merchant ship, and poor nobles can effectively defend their castles by arming the cooks and scullery maids in an emergency. Getting people to work in close ranks takes more time and energy, and was generally picked up by the people of walled cities as a means of preserving their freedoms against the nobility, but this implies a level of social organization which might not be there yet. [Answer] I guess the single most valuable bit of knowledge your timetraveller has, which is also quite easy to use, is his knowledge about hygiene, even if it was only the most basic ideas. He need not be an apothecary to boil water before he drinks it, let alone before washing a wound, or wash your hands before touching a wound. To cannibalize @SJuan76's answer a bit: he could even use holy water to avoid conflict with the church, and he might even boil the water secretly to avoid unwanted attention. Practically everything else he knows requires some infrastructure and a lot of other people's acceptance. [Answer] Since you can read and write I suggest enter a monastery. You can easily impress your colleagues with your fast and clean writing if you manage to insert a small ball into the tip of your quill ([László Bíró](https://en.wikipedia.org/wiki/L%C3%A1szl%C3%B3_B%C3%ADr%C3%B3) sounds familiar to you?)... When you start to be a respected member of the community you could introduce a couple of nice innovations like the heavy plough (wether it already exists depends on the year and place you land in) and the three-field system: the increased productivity in you monastery-owned land will be a good basis to climb the ranks and become Prior! You may then introduce some more advanced technology, like the flying shuttle loom, and even open the first public school, so that your monastery will be the centre of innovation: compulsory school for age 5 to 8 and then buy the most promising children from their families to continue with more advanced studies! And of course always do it for the greater glory of God ;) [Answer] There are several options: 1. **Steel**: Good steel is not that hard to make once you know how to do it, but nobody in Europe knew how around the 10th century. Even if you can't do it cheap, you're going to do it better than anyone else, which means you can make better armour and weapons or just plain make more money 2. **Glass**: Just like good steel, nobody in Europe, knows how to make transparent glass. Just like with steel, once you know how, the process is relatively simple. If you are the only one in the world who can make transparent glass you can make a lot of money of it. 3. **Alcohol**: not just for drinking but for hygienics as well. 4. **Agriculture**: There’s been some development in agricultural methods in the past few centuries that a protagonist could exploit; fertilization for example. 5. **Cooling**: While a refrigeration system might be more than he can handle, a primitive cooling box is definitely possible. All it takes is a “house” with two sets of walls to provide some insulation from outside heat. Go to a place with ice, load the box and transport the ice to a hot place to sell. 6. **Basic math**: Pretty much nobody in Europe could solve any real math problems. The advanced math in Europe in the middle ages was at the level of basic high school or maybe even lower. 7. **Reading and writing**: Except the clergy, almost nobody were able to read or write in Europe (well, except Scandinavia before it was christened). 8. **Resource knowledge**: The protagonist might know where some large resource sites lie, that haven’t been discovered yet (coal, steel, silver, gold, …). 9. **Knowledge of the west**: Knowing that there’s a massive “unsettled” land to the west (the Americas) and what happened once Europeans got there (people started to drop like flies from all the diseases that where introduced) could also be exploited. 10. **Other “simple” technology**: a basic grasp of some of contemporary simple technology could be used to recreate it in the past; a fully functional internal combustion engine is likely be out of the question, but a steam engine might not. A jet engine, which is surprisingly simple to make, might also be a possibility. Take care: a lot of the stuff we use today is *only* possible because of materials that have been gathered from all parts of the world! It would not be possible to make anything which uses rubber (or latex) in medieval Europe! There are quite a few problem he would have to overcome; most of the languages spoken would so dissimilar to what he would be able to understand, that he wouldn’t be able to communicate with anyone else. Except if he’s Icelandic… Your protagonist might get infected with something he wouldn’t be exposed to in modern times, simply because the infection has been, as good as, wiped out in the passing centuries. He might also bring a few nasty bugs with him and might cause a major plague to ravage the world… EDIT: Forgot about paper; **paper** is much much much cheaper and faster to make than parchment and offers almost all of the advantages (except that it degrades a bit faster, I don't know of any disadvantage). If your protagonist is able to make paper he’s sure to be able to make a lot of cash very fast. [Answer] How about this. Become a medical doctor (in any manner that it is possible) and then apply simple cures to a few diseases where these would be both easy to implement and very rapidly successful. For instance, digitalis (foxglove) for heart failure, or vitamin c (fruit extract) for scurvy (and other vitamins for other vitamin deficiencies), seafood (iodine) for goiter, etc. They could either join the Benedictine Monks or become a traveling herbalist. Herbalists were [apparently not condemned as witches, etc., until the late middle ages](https://en.wikipedia.org/wiki/History_of_herbalism), so you'd be ok. (Added...) The idea is to be like the patent medicine people. Once you get some rep, charge a lot for your 'miracle' cures. Get rich and move up in the local hierarchy. THEN you can have the resources to implement some of the more cost and time intensive approaches. For instance, have wires fabricated, build a primitive battery, then build a small demonstration telegraph. THAT would get attention. But you'd need credibility and money to even start with more complicated devices like that. You need a toehold in the society. [Answer] The printing press ... Invent the printing press and allow the passage of knowledge. To avoid suspension print something nonthreatening like the bible in a small Germanic state, with and unassuming name like Gutenberg [Answer] 1. Make sure to survive, which won’t be possible on your own – might require simple manual labor. 2. Learn the local language and study Latin. For that, befriend the local priest or monks and disclose your ability to read (although 11th century calligraphy will require some time to get used to). 3. Write down your school knowledge at least of math and hard sciences. Be careful with evolution and astronomy. 4. Exploit your special expertise from job training and hobbies. This is very individual. Some things to invent if you got the expertise, in no particular order: * Steel * Metal-enforced plough and direct sower * Fertilizer * Pasta * Distilled alcohol * Gun powder * Paper and printing * Windmills (good gears etc.) * Concrete * Manufactories * Mechanical looms * Bikes or trikes with pedals * Porcelain, glass, mirrors * Perspective drawing * … [Answer] Technologically, maybe the most profitable invention could be the **steam machine**. You only need a closed vessel with an aperture, and something for the steam to push on to see it in action. If someone has issues with how satanic it is, just allow them to use the steam machine with holy water so they see it is not affected at all. For example, a short **steam train** allowing to easily move troops/merchandise along a nobleman territory could be something very interesting to such nobleman. Tactically, your protagonist does not want to go into the town main square and shout that he comes from the future; he probably wants to directly approach the local feudal lord and stage a private demonstration to pique his interest (not that it is without dangers, as you always risk running into someone who thinks you are a liar or who does not see how practical science may be). [Answer] A late answer, but as most other replies that essentially rely on devices, I would put emphasis on more knowledge-based elements. What about **banking** ? In the past, Jews were not forbidden by their religion to manipulate money, and they made great profit at it. Same goes for for the Knights of the Temple, who had the trust and a network that enabled the lending of money on a large scale. Understanding some fundamentals of economics may really help to make money. Note that in both cases, some powerful people desperate for gold may try to grab, like the king of France Philippe IV le Bel did. **Cryptography** may also provide help to powerful leaders, both to help confidentiality and break some (usually basic) codes used at that time. **Labor division and organization** would allow for proto-industrial development, event with the local energy (water mills). **Medicine** and basic understanding of the body may really help to give advice. Remember that sterilization is a relatively recent discovery. [Answer] Well, you've got to plan it out. You need to be calm and deal with the situation as it is. 1. Survive - dead man tells no tales. Don't tell outrageous things or you might find yourself burnt at the stake. 2. Rise in ranks - Be the very best. If by any chance your caught by a slaver: be the best slave. Regardless of what situation you find yourself in, you need to rise from the bottom. 3. Take risks - Take calculated risks. Regardless of past present or future you will need to take risks. 4. Use everything - I mean everything. From your very first sweat to your marriage. Everything can be used to achieve your goals. Use of other people will go a long way. 5. Throw away the useless - If they are useless, they are a burden, if they are a burden, you throw them away. 6. Cold heart- You live in the medieval Europe, cold heartedness will allow you to survive. 7. Exploit the weakness - You find a chink in their armor? break it! they are down on their backs, kick them screaming till you not hear their screams anymore. Don't hesitate to do so since they won't hesitate to do so. 8. Women - Women are the biggest weakness a man can have. Keep them within arms reach. 9. Priorities - Know what you want and what you are willing to risk for it. 10. Time - you won't live forever. Finish everything in timely manner and evade siege as much as possible. [Answer] The problematic bits is "rise on power" not being burned by the church. So, others have answered about knowledge and tools it can exploit, but now how rise on power. *How do that*? **EXACTLY AS EVERYONE ELSE.** Is that simple. Pick any successfully power-player (Alexander the Great, Caesar, Spartacus, Napoleon, Sun Tzu) and look at what was their path. You will probably note is hard without a proper blod-line (how about apply your knowledge on how treat a lady of influence!) or a sucesfully take-over, but eventually you need a army or be backed by one somehow (like being the power-behind-the-power). ]
[Question] [ In my fantasy world I am going for a Mesozoic-inspired biome, so I want there to be no grasses. This means no wheat, rice, corn, and the like. I imagine that the staple crops will be tubers, legumes, cabbages, roots, onions, and mushrooms. This made me think: Most of the long-term storable vegetarian foods I know about are grass-based (grains, biscuits). Which non-grain vegetarian foods would be best for long-term storage? My stories are set across centuries, and the available technology ranges from late medieval to early modern period, perhaps 1500 through 1900. [Answer] **Depends on how much processing & preservation you allow** Most anything edible can be made into a long-term storage item if you cure it and keep it away from the ground or moisture. Drying, smoking, salting, pickling, etc, there are many ways to preserve things. Though if you want something a little less processed... Try nuts. If you can farm them, nuts are a great way to pack away nutrition for hard times. Just ask just about any animal whose anual task is collecting them before winter and they'll tell you the same... if they could talk. Alternatively... grow pine trees or some other conifer if they're available in your world. Not only will they give you wood, you can eat them. From the bark to the cones to the resin and even the needles, most conifers are some degree of edible. Some even have medicinal properties. Pregnant women might have to be careful about eating conifer-matter though as there are some cases of pine needle ingestion leading to abortions in cows, but other than that they should be fine. And hey, pines have nuts too, so, you know... Go nuts. [Answer] Dry beans (soybeans, pintos, Great Northern, etc.) keep almost forever with no more effort than keeping them dry. Additionally, legumes contain "complete" proteins, so can substitute for meat, nutritionally. Tree nuts also keep well, for a year or more in the shell. Sunflower seeds can be soaked in brine and will then keep dry for a long time. Some gourd fruits (winter squash, in particular) will keep in cellars without additional refrigeration through a summer and well into the next winter, as long as the skin is intact. Further, pumpkin seeds can be dried for long term storage. [Answer] Many Pacific Islands never had edible grasses but solved this problem using fruit. Big ones like breadfruit are best, [fermented breadfruit paste](https://www.persee.fr/doc/jso_0300-953x_1984_num_40_79_2544) was used for voyages that might take months. But some has been found to be still edible 50 years after they were made. Some places like the Marquesas breadfruit was the staple but didn't produce fruit year around so they fermented the paste and used it for 3 months and more at a time. [Answer] [Chuño](https://en.wikipedia.org/wiki/Chu%C3%B1o) is an Incan process of freeze-drying potatoes. The processs involves leaving potatoes to freeze at night then dry out in the day, then trampled to remove any remaining water. The resulting dehydrated potatoes can last for decades. It can be made into a flour. So I'd say potatoes would make a good grain replacement. [Answer] A warning if you're looking for something Mesozoic-era: most angiosperms had not evolved until the late Cretaceous, including tubers (Solanacease, Euphorbiaceae), beans (Fabaceae), or cruciferous vegetables (Brassicaceae). If anything, grasses like primitive rice were the first to evolve. To have a Mesozoic-like setting, you'll need to be careful to avoid really any type of flower or fruits, or most vegetative structures we see today. I recommend this site for some ideas on gymnosperm "fruits" or go with pine nuts: <https://www.indefenseofplants.com/blog/2018/10/24/gymnosperms-and-fleshy-fruits> [Answer] # dates Remarkably durable food for vegetarians, last several months at room temperature, a year in modern, cool storage (4-6 degrees celcius). A cave, relatively cold environment, could be used to store dates for the autumn and winter season. <https://www.doesitgobad.com/do-dates-go-bad/> [![enter image description here](https://i.stack.imgur.com/UDUe4.jpg)](https://i.stack.imgur.com/UDUe4.jpg) [Answer] Tubers and roots can be dried and processed into flour and kept indefinitely. The flour can be reconstituted into pretty much anything that wheat flour can be used to produce including puddings, breads and cookies. The protein content will vary depending on the specific specie and will dictate how easily a bread can be made from it. Gluten, the stretchy part of bread dough, is a protein. As others have noted, any type of seed or nut will typically have low enough water content on it's own to be stored for quite some time in cool, dry and dark locations. Keeping everything away from vermin will be the challenge. [Answer] Booze. Ferment whatever you have. Alcohol is a great way of converting marginal foods into something calorific. In the given time period, small beer was the normal drink for people of all ages. It provides food and hydration, and will keep you going through the winter. Yes, also pickle, salt, lacto-ferment... but... booze! ]
[Question] [ The world is broken up into seven realms: Australia, North America, South America, Antartica, Asia, Europe, and Africa. Each realm is populated by large numbers of people, and travel between realms is commonplace. This form of travel occurs through a series of realm gates, one of which is located within each realm. This gates link to a massive, in-between realm that connects the smaller realms to each other. One must pass into this space in order to connect to a gate that will transport them to the realm of their destination. Magitech has been developed by humanity, which has caused it to enter its industrial phase in history. Magitech is built by an individual or group of people infusing a particular item with their own mana, empowering it with certain properties it would not otherwise have been capable of. Society runs on this form of technology, such as computers, phones, cars, etc. It is available to all of the population and has become a center point of life. However, technology can only work within the realm that it was created. If taken to an alternate realm, it would not function. This prevents trade from occurring between realms, even though travel between them happens on a regular basis. The reason it is set up in this way is because I wanted each realm to develop their technology independently from each other. Because of this, societies will sometimes develop their own form of similar products, while others would not be able to develop certain items at all. This would lead to differences in tech levels, with some realms being highly advanced and others being less modern and primitive. However, I can't justify why tech from one realm wouldn't work in another neighbor. Somehow linking the reason to mana made sense. However, humans also have mana and can pass through these realm gates just fine, as well as use magic with no issues. How can mana prevent technology in one realm from working in another? [Answer] Lack of standardization, plain and simple. Think of railways, each country can have a different distance between the rails, lacking a standard trains from country A cannot travel in country B. Same for socket plugs or energy grid: different plugs layout or network rating in terms of power output and frequency can make inter-usability impossible. A valid reason for preventing standardization is to increase safety from invasions: you don't want your invaders to be easily able to use your railways, plugs and so on. [Answer] ### They use region codes to allow per-region pricing Like [DVD region licensing](https://en.wikipedia.org/wiki/DVD_region_code), those who create magic-tech negotiate the rights to sell and distribute their creations within certain regions. Regional marketing teams pick the price-point for magic-tech based on strategy, local competition, local values, and disposable income. Eg in one market we're trying to undercut a local competitor so are selling magic-tech at a loss, in another we have a monopoly so sell it for 3x the price. We also have a low-feature version we sell in low-income markets, which we don't want to compete with our product selection in premium markets. By intentionally disabling the tech when someone travels to a different region, we allow our different marketing strategies to coexist and not undercut each other, enabling magic-tech products to achieve maximum profits. [Answer] # Gods† Each realm has its own pantheon of gods, including one or more responsible for magic. The magitech is in tune with the rules and rituals of magic set down by each realm's god(s), the gods of the other realms can sense it immediately. Gods, unfortunately but not unexpectedly, are capricious and also jealous. So they block the magitech from other realms. From other gods. And while it might be possible to spoof which gods sponsored certain items, that just runs the risk of divine retribution when they find out. **†** instead of gods, you could make it spirits that speak different languages, thus don't understand magitech from other realms, or runes that work in one realm but not others. [Answer] **Negative mana in the inter-realms space** As you said, magitech allows to enchant items so that they can perform more advanced or otherwise impossible actions, or gain improved features. For instance, I could harvest a batch of bananas, then enchant them so that they become bananaphones (which allows people to use them to comunicate to one another), infusing them with enough mana to become permanently enchanted. This is possible because inside every realm there is a positive (or null) mana-field. Unluckily, the inter-realms space is a region of negative mana, which means that whatever has mana, keeps on losing it as long as it stays there. Conseqeuntly, as soon as I enter the gate with a wagon full of bananaphones with the purpose to sell them to another realm, the negative mana starts to drain magic power from whatever positive mana is present. As soon as the mana level of the enchanted items goes downto zero (or anyway below a threshold), the enchantment vanishes, and the bananaphone is reverted to a normal banana. I still make a good deal, since people of the other realm find that my bananas are good also as food, but of course I learn that it is not possible to move a magitech item from one realm to another through the portals... Humans are affected too, but, since they are living beings (and their mana is more a latent power than an enchantment), as soon as they reach the other realm their mana level restarts to replenihsh, and their health is otherwise unaffected. But for an item, as soon as the enchantment is dispelled, there is no way to enchant them again (if not with a completely new spell). An interesting consequence would be that inter-realms wars would be almost impossible (enchanted weapons would be reverted to normale weapons, while the wizards of the invading army would need time to refill their mana and launch spells, wgich would make them very vulnerable). This would be interesting, since kingdoms could still try to win an upper end in trade (and military), by trying to discover ways to shield magitech from negative mana, or trying to find safe alternative routes to connect to other kingdoms. [Answer] It may be simple. Humans are versatile and adaptive, so their magic is as well. In other words, while other realms have different kinds of mana, humans can adapt to use these different strains of mana as easily as they do their native mana since magic is an extension of their being. However, magic in an *object* is not versatile; while magic connected to a living thing can adapt, being an extension of their being, once magic goes inside an object, that connection is broken and it becomes an extension of nature, drawing off the ambient magic to power itself and only fulfilling its given function. It's like a rocket; you can prep all you want, but once it's fired off, you no longer control its path. Instead, physics takes over. Magitech only does what it's designed to do for this reason, and that includes its power source as well. If it was designed in a certain realm, it can only draw power-and therefore function-in that realm. Interestingly enough, this means that this limitation can be circumvented by making magitech in an in-between place; such an item should work in the "gray area" and whatever's connected to it. In conclusion, once magitech is brought into another realm, it *can't* adapt to and absorb the other realm's mana. Granted, this removes the "humans have no issues using magic in another realm" clause, but it is also a plausible answer to your question. Hope it helps! [Answer] It's not just the user's mana. It's also the mana of the land. This can be because * a person is just not powerful enough to fuel such things * mana can't be chopped off that neatly, it pulls on mana about, being fluid and mixing with the mana about * when magitech was first being developed there were some extremely nasty battles, and each realm developed a massive spell unified the realm and its mana, and prevented any magitech not drawing the land from working [Answer] **Travel between realms harms the devices.** If you travel by boat/air/rail you will inevitably pass through an area with no mana. When magical devices which need mana in them constantly even at low levels pass through these areas they instantly discharge all mana to the surrounding area and damage the components. If you travel via the realm gates, the in-between realm has the opposite problem. It has too much ambient mana and it fries the devices (sorta like an EMP would). This system would allow an adventurous merchant to try and map a trade route between realms but would never allow for mass transit of goods enough to change technology levels between them. Tech could potentially make it but a total loss of cargo would make it hard to be sustainable. [Answer] To expand on [Dutch's answer](https://worldbuilding.stackexchange.com/a/195563/21222): machines must be plugged on ley lines to work. The ley lines are invisible and ubiquitous, but they are managed differently in each country. For example american appliances usually run on 110 [thaums](https://wiki.lspace.org/mediawiki/Thaum), while most european ones run on 220 t. Plugging magitech in a line with a thaumage lower than what it is expecting can damage its parts, but on higher thaumage than what the machine expects it can cause an explosion. [Answer] Similar to the ley-line answers but a bit more geographic, magic *phase* is keyed off the geographic location based on position relative to the Earth's magnetic field, so effectively spherical coordinates. There's a further complication of severe dissonance because of refraction around the boundaries of tectonic plates. This, like others have suggested, doesn't really solve the Eurasian issue but it does allow for Russia to be interestingly split with part in the North American plate. [Answer] Having different amplitudes, frequencies, and phases. The least consequential of the bunch is ***phase***. Magitech operating in a phase different than intended would merely mean that it would be at a lower efficiency (i.e. a fireball producer creating smaller fireballs). The next least important is ***amplitude***. While commercial products are very carefully made to work in only one region, to reduce costs for the customer and therefore undercut competitors, homemade stuff tends to be able to handle a wide range of amplitudes (i.e. a commercial fireball blasting out a bunch of energy and then breaking). The worst to have different is ***frequency***. Magitech can only be built for a single frequency, because having it be able to handle more than one frequency would essentially require a closet sized thing rather than a briefcase sized things, due to the incredible power requirements and the drastic loss of efficiency from handling multiple frequencies. While such technology exists, it is extremely rare due to lack of demand for closet-sized fireball generators, while a normal fireball generator trying to use a different frequency would have extremely unpredictable behavior for the few seconds before it implodes or just stops working and turns into a first-rate brick. For this reason, most commercial products have an emergency failsafe if it is receiving an unexpected frequency. [Answer] **Long range communication.** Mana users of different realms use different types of communication. Add enough persons using a certain type and it interferes with short range mana transmission in your devices. Shielding is realm dependent. [Answer] This question would be easy to answer, were it not for this little bit: > > humans also have mana and can pass through these realm gates just fine, as well as use magic with no issues. > > > So, a antarctic car doesn't work in North America, but Tod can cast his Antarctic fireball in America just fine. It can't be that they can't move between regions like in McTrooper's answer, because what keeps Tod from just making one in North America? My answer is that each continent has it's own "flavor" for magic. The continents and people from them are sources of this flavor. When you bring a machine to another continent, the constant emissions of another flavor tear it's workings apart. But a person cans still cast spells because they are their own source, which also protects them from being ripped apart. ]
[Question] [ For the Universe I am creating humanity has devolved into groups of scattered tribes. This is due to the fact that we ran afoul of a *really* nasty alien race, who decided to leave us homeless. A coalition of races had banded together to fight this menace, but mankind ended up with the short end of the stick. It is the Great *Diaspora*, and we are only hanging on by our fingernails. The problem I am having is how to thoroughly destroy or at the very least render uninhabitable the places Man once called home. If it were only Earth it would be a simple enough matter, but by the time the attack takes place he *also* has colonies on Luna, Mars, Ceres, Callisto, and Titan. How can I muck them up badly enough that we have to now seek a Promised Land elsewhere? Ceres I figure is small enough it could just be reduced to rubble, but what about Luna? If you destroy the colony there, what would prevent them from setting up new ones a few hundred miles away? At the moment all I can think of is a "Gray Goo" weapon, short of blasting multiple planets and moons to smithereens. I am hoping there is another option out there I haven't considered. EDIT: I'd like to hold onto the Sun. You know, sentimental reasons. :) [Answer] Let's turn our thinking around. Instead of asking, "how could alien attacks send humanity into a diaspora?" we can ask, "what would aliens do if they *wanted* to scatter humanity like this?" Say, for instance, the aliens don't want to permanently ruin the worlds that the humans have colonized (because those worlds could be used by the aliens down the line), but they want to keep the humans off of them for a while. I've come up with a machine that could do the trick. It's a massive, self-powered vehicle the aliens have developed, which burrows into a world's surface once it lands on the least-defended area of the planet. Once deep in the planet's mantle, it sends out extremely powerful EM pulses constantly, which disrupt electronics all over the planet but dissipate harmlessly at larger ranges. Any human habitats on the planet will immediately lose life support and become uninhabitable, forcing an evacuation or worse. The humans can't just move to another location on the planet, because these EM pulses don't stop. Perhaps with some ingenuity, they could build Faraday-cage-enclosed habitats, but it would be dangerous setting that up in the first place while that machine is still running, given that all of humanity's habitat-building tools are themselves electronic. But couldn't the humans just destroy the device, you ask? Well, sure, maybe they could get a high-power enough laser from far away enough in space to vaporize a hole all the way down and destroy it, or something like that. But that takes a lot of time and a lot of resources. Maybe some governments were working on just such a solution, and the aliens eradicated them before they could finish. These planet-wide EM-producing digging machines are, of course, very expensive for the aliens as well, so it makes sense that they only sent them against the main human settlements, and have spared the scattered outposts. [Answer] **Rocks** Simply put you throw rocks at stuff you don't like. Fortunately our solar system is *full* of rocks just waiting around doing nothing, so we just grab a few (OK, more than a few) and direct them gently at the source of the problems (any inhabitable place) and wait for nature (and gravity) to takes it course. In the due course of time you can not only wipe out all life, but ensure it won't be producing or supporting any life for millions of years. Everyone wins. [Answer] The answers all suggest multiple plausible ways to render the Solar System uninhabitable, but suffer from some flaws, such as requiring a long time frame to work, or require a great deal of resources. I will refine the process and suggest the aliens simply have to fire one RKKV (Relativistic Kinetic Kill Vehicle) into the Sun. Striking the sun with that amount of energy and using the extreme speed of the RKKV to deliver the energy deep into the Sun, many processes will be disrupted and the Sun will likely emit massive flares and other radiation events which will scour life from all exposed surfaces. Since the Sun will be unstable for years, there is really no hunkering down and waiting to fix the blasted surface installations, especially since we are talking about the sorts of flare events which would strip large portions of the atmosphere from the inner planets. Larry Niven's short story "Inconstant Moon" describes what such a scenario would look like from Earth. [![enter image description here](https://i.stack.imgur.com/H83uC.jpg)](https://i.stack.imgur.com/H83uC.jpg) *Use SPF 10,000,000* <http://news.larryniven.net/biblio/display.asp?key=52> > > This story raises the question: How would you spend your last night on Earth? When the Moon suddenly starts shining brighter, Stan and Leslie realize the sun must have gone nova and they only have a few hours until the Earth rotates into the deadly sunshine. This story won a Hugo Award and was made into an episode of The Outer Limits. > > > As a possible bonus, after the flares settle down, the Sun may also go into a Maunder minimum, producing less energy and making any sort of biological or industrial recovery even more difficult. Even K2 civilizations have limits, so being able to deal with the opposition using only one RKKV is much more efficient than trying to strike every planet, moon and free flying object in the Solar System. [Answer] **How to reduce things to rubble *easily*** Relativistic kill missiles are your best bet for thoroughly destroying inhabitable places in the solar system (which is technically every one of the nine planets and most of the dwarf planets, given enough technology) is to use relativistic kill missiles; the aliens could just send kilometer long projectiles moving at a decent percentage of the speed of light, which, on impact, would convert matter into energy at an efficiency possibly better than even matter-antimatter annihilation (which loses matter-energy efficiency by radiating out neutrinos). A relativistic kill missile need not have any explosives, because its mass is all it needs, along with some thrusters, which can use fusion reactors, or pushing lasers, to accelerate to well over 50% the speed of light. Just a few [teratons](https://en.wikipedia.org/wiki/TNT_equivalent) of iron or some other dense material, the procurement of which would be child's play to any K2 or above civilization (I'm assuming these aliens aren't from our solar system), would be needed to build the missile; and, when it hits its target at a decent fraction of the speed of light, can bake even a planet and render it uninhabitable. The K-pg impactor caused a mass extinction, but was moving nowhere near the speed of light. A larger asteroid, or one moving a lot faster, could have rendered the planet uninhabitable. And that's what a relativistic kill missile could do. [Answer] Self Replicating Drones The enemy race drops a 3d printer/mobile factory on an asteroid. It starts building more of itself, and creates swarms of drones. It keeps doing this. Eventually there are so many drones you can't have a civilization anymore, either because enough of the mass of the solar system is converted into drones, or you give up and leave and the factories go into hibernation mode. [Answer] A small stream of [strangelets](https://worldbuilding.stackexchange.com/a/113655/21222) in a series of flyby trajectories around the sun will do the trick. As long as the sun is not touched, it is safe. Everything else becomes lethal to the touch. Since the ΔV from even Mercury to the Sun is immorally huge, the sun should be safe. Add to that, solar wind pushes stuff away from it... Over millenia other stars around the sun will be disassembled, but the Sun will be fine. As for the Earth, Moon, asteroids, comets... Each and every one of them will disintegrate. [Wikipedia, for example, says this could happen if even one strangeled touched the Earth:](https://en.wikipedia.org/wiki/Strangelet) > > This "ice-nine"-like disaster scenario is as follows: one strangelet hits a nucleus, catalyzing its immediate conversion to strange matter. This liberates energy, producing a larger, more stable strangelet, which in turn hits another nucleus, catalyzing its conversion to strange matter. In the end, all the nuclei of all the atoms of Earth are converted, and Earth is reduced to a hot, large lump of strange matter, the size of an asteroid. > > > [Answer] Your aliens could flood the moons, planets orbits with high intensity radiological materials. Fast Neutron radiation is very bad for humans and things like the magnetic field surrounding the Earth and Jovian moons won’t provide protection since neutrons have no electric charge and aren’t effected by magnetic flux lines. So dusting the regions our habitats orbit through with isotopes of Californium would rain down deadly radiation. And, depending on how much energy they have to work with, they could generate intensive E-M fields. Our natural protections like magnetic field will attenuate the E-M radiation, but at enough high intensity it will cook us like a hotdog in a microwave. Populations living in totally enclosed metal cages (faraday cages) would survive if the cages didn’t melt. And the biospheres would be wrecked. And, biological attacks would be effective. If humans had sealed colonies on hostile moons like Io, they might be protected against these attacks — except E-M since they’d qualify as faraday cages, or faraday cages in faraday cages. And, then there is good old fashion sabotage. Infiltrate and overload the reactor or poison `water supply. [Answer] I'm going to take a simplistic shot at this, forgive me if I don't 'color inside the lines'. In the OP "uninhabitable" and "diaspora" made me think that a civilization capable of such destruction would also likely have no issues with Biological weapons. In the basic premise of the pathogen seen in films like "Alien: Covenant", I suggest that a universally lethal-to-all virus/prion or other pathogen would fit the job. As a self-replicating, incurable weapon...deploy once, then step back and wait. [Answer] Depending on what kind of technology your alien race has, you could use something with a very high mass to gravity slingshot the planets into the sun (or at least near it). I believe that vaporising a planet makes it uninhabitable. [Answer] So, to take a stab at this, destabilization of the oort cloud, millions upon billions of icy debris, with a vast number of objects over the size of 1km. A dead star swinging by the very edge of our system could easily dislodge of a few billion kilometer long pieces of ice. Just for good measure there could be ancient dormant prions, as mentioned in a previous post, that inhabit them. Fast forward a bit and you literally have an entire solar system getting pelted nonstop by large glaciers filled with deadly viruses/bacteria, or whatever you want them to be, quickly causing the entire solar system to go to shit. This would take care of pretty much any base that's not heavily armored, even if it is, just chuck a few hundred abnormally large iceballs at it. Lastly, for the long term, instead of rebuilding, just say that with the billions of asteroids that are being swept up, it'll be a few hundred years before its cleaned up enough to not have to worry about being on the surface of a planet. Either that or viruses. [Answer] ## Make other options more attractive. The only easy place to build inside our solar system is earth. Everything else kinda sucks. We could build a colony on Mars or some of the moons of Jupiter but it's pretty far from ideal. The only reason we consider it at all is because there aren't any other options we can reach. If this event got humanity in contact with other aliens, and provided FTL technology, then it may simply be that we don't return to our old home because Earth has been made uninhabitable in some way and ***there are so many better options now.*** Turns out the universe has loads of Earth-style planets with no intelligent race living on them so there's simply no reason to go build a domed Mars colony or deal with hostile atmospheres or cold climates. Just pick one of thousands of known, hospitable, unclaimed, Earth-like planets and starting the colony is far easier and cheaper. [Answer] #### Spheres of cobalt 59 orbiting the sun The alien placed a lot of spheres of cobalt 59 in orbit around the Sun. The orbits are so eccentric that at the perihelion they graze the Sun surface and the heat ablates a layer of the surface, then the solar radiation turns it into cobalt 60. Now you have a very radioactive solar wind and, since those atoms were not in the plasma, many of them are not ionised therefore they can pass through the barrier of the Earth magnetic field. [Answer] ## Tax The battlecruisers hang in the sky, their ubiquitous blue scanners constantly probing for....untaxed transactions. The aliens have decided they would quite like Earth....I mean, we're 100% free to stay. Welcome even. But we have to pay our fair share for our development (and the galaxy's infrastructure, and the war in Astanius, and the Emperor's harem cruiser, and the bureaucracy worlds, etc). There's an 85% income tax, a 75% capital gains tax, a 5% wealth tax, a 4% transaction tax, a 25% VAT, property taxes, as well as excise taxes, levies, development fees, user pays charges, local taxes, and rates of all descriptions. There are no deductions or dividend imputation or income splitting. Other star systems are tax free, and you can purchase an FTL for a mere 2000 credits (plus 4000 tax). [Answer] ## They stole the Sun. No, not *literally* - that takes too much power. But they have some basic technology that can tap into the Sun's own magnetic dynamo and spin a ball of magnetic plasma around the star - basically, turning it all into one giant sunspot. A sunspot which is very carefully calibrated and aimed to beam energy out on many specific vectors to projects the aliens have going in deep space. To the rest of the cosmos, the Sun is now a brown dwarf perhaps occasionally eclipsed by frozen planets with little if any gaseous atmosphere. The aliens do not believe in *enslaving* humans. The humans should be more than willing to spend their lives working for a small fraction of the energy they once thought of as falling free from the sky. A policy they can argue is entirely in line with native traditions, as several centuries of Earthly capitalism had assigned commons lands, unknown natural resources, even drinkable water to the powerful in much the same way. [Answer] ## Destabilise Pluto, setting off a series of disasters With a small change of orbit, Pluto can be made to viciously slingshot around Neptune. It hurtles towards the inner solar system and wrecks Earth. In the meantime, Neptune's orbit now brings it into collision with Uranus and eventually Saturn and Jupiter. The Solar System is now the Solar Splat, and mankind can't even decide if it began with the aliens altering the orbit of a planet or not. Depending on the details, mankind gets weeks or a few years to get out of the area as Earth and the colonies are destroyed in sequence. ]
[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/75200/edit). Closed 6 years ago. [Improve this question](/posts/75200/edit) Although I realize it is technically wrong, I often draw comparisons to naval combat when thinking about potential combat in space between starships. While you can compare a capital ship in space with a capital ship in the seas and the same can be said for fighters/starfighters, I find it difficult to imagine something similar to a chopper or a helicopter, which has a great many applications in modern times, even on sea. As far as I'm concerned, a fighter/bomber/interceptor is a rapid reaction force that by virtue of its engine excels in any situation where speed or time is of the essence, and/or the terrain is wide open. A helicopter, in general, is far more maneuverable and flexible (at the cost of speed) compared to a jet. This is most important in urban combat, but even on the wide sea a chopper can hold its position for an extended time, whereas a plane can't. On the other, space is literally as open as it gets, so urban combat, unless we talk about "urban" being a huge starship, does not exist. **Now, with regards to comparing it to space combat: Would there ever be the need for a force that, like a helicopter, excels in maneuvering and holding its position, yet is more agile and speedy than any starship ever is, while being more flexible than a starfighter?** **Do you see something like a space-helicopter having a role in space combat?** EDIT: ship maneuverability contrary to apparently popular opinion, fighters **are** more agile and speedy than capital ships, both in acceleration, deceleration as well as turning into either axis. EDIT: in regards to tech - no individual FTL, but static in-system jumpgates. - laser, railgun, missiles are live - scenario comparable to Babylon 5 + BSG in regards to maneuverability and shiptech, FTL aside. EDIT: To be more specific regarding the spaceships and starfighters Imagine either a *Babylon 5 Omega Destroyer* or a *Battlestar (Galactica)* or a *Venator SD* as the capital ship and either a *Starfury*, *X-Wing* / *TIE-Fighter* or a *Viper* as the fighter/interceptor. Would there be a need or role for a unit slightly more massive than the fighter, but way, way less fast and more maneuverable. [Answer] A helicopter's utility does not only lie in its ability to hover and take off vertically, but also in its versatility. A present-day warplane is basically a pair of engines (or sometimes just one engine) with a cockpit and wings glued on. They're super specialised pieces of equipment, with a very limited set of jobs, and they're more or less useless at anything else. Military helicopters, on the other hand, tend to fill a wide variety of roles. They can transport troops and stores, function as gunships, they can carry airborne radar, sonar, or EW equipment, can perform SAR operations, etc... Your space fleet will likely still need a craft to fill these roles. In a space fleet, your starfighters would be like Babylon 5's Starfuries - uncompromisingly optimised for combat. A set of the biggest engines you can reasonably carry, a cockpit, and a weapons system, and nothing else. Your capital ships would likely be self-sufficient cities, too massive for fine manoeuvring (it would be possible, but expensive on reaction mass). Your 'helicopters', then, will be the equivalent of shuttles or ships boats - small, probably modular utility craft for transporting cargo and personnel, easily customised for different missions. They'd also likely be your primary air support for planet-side operations. Some examples: ## Battlestar Galactica In the rebooted *Battlestar Galactica*, the titular Battlestar predominantly operates two spacecraft. The [Viper](https://en.wikipedia.org/wiki/Colonial_Viper) is a classic starfighter - single man cockpit, tiny wings, huge engines, and a pair of guns. Powerful, but inflexible. When the fleet needs ECM support, or transport of passengers or cargo, FTL scouting, SAR, or any other utility function, they call on the [Raptor](https://en.wikipedia.org/wiki/Colonial_Raptor). It has a wider body, lighter engines, and a significant interior volume, enabling a wide range of missions. ## Babylon 5 The [Starfury](https://en.wikipedia.org/wiki/Starfury) is iconic, of course, but like any starfighter it's very limited in the roles it can fill. It's a pure war-fighter - no cargo capacity, no passenger capacity. For those jobs, the EA has shuttles - both [space-only](http://babylon5.wikia.com/wiki/Earth_Alliance_Crew_Shuttle) and [atmospheric versions](http://babylon5.wikia.com/wiki/Kestrel_Class_Atmospheric_Shuttle). ## Star Wars Look at an [X-wing](http://vignette3.wikia.nocookie.net/starwars/images/d/df/T-65C-A2.jpg/revision/latest?cb=20160224040200) - it's a beautiful ship, but where off earth could you put a passenger?? There's apparently some light cargo storage on the underside for the pilot's personal effects and survival gear, but there's no way you could use this ship for hauling ammo or food back and forth across vacuum. Instead, the Alliance has access to some [U-wings](http://vignette4.wikia.nocookie.net/starwars/images/e/e3/U-wing-SW_Battlefront.png/revision/latest?cb=20161213062352). These are a much more practical utility vessel, with a roomy cargo/passenger space, and mountable guns to provide support fire, as well as being capable combatants themselves. These, then, are your helicopter analogues - the Raptor, the shuttles, the U-wing. They're versatile, efficient, and allow starfighters to do what they do best (presumably, fight stars). [Answer] **Not really** For starters: There is no such concept as 'holding position'. If you want to stop accelerating then you stop accelerating, other than that there is only motion relative to other bodies in space. The whole idea of 'I need to do something active to stay still' doesn't apply. Secondly: Any 'star fighter' in space is already going to be more like a helicopter than a plane. Building star fighters like planes makes no sense, as there is no need to bank, no need to be streamlined and turning is done using thrusters, not by changing the angle of a control surface relative to the air. Any star fighter should already be able to aim directly at an enemy while engaging in evasive manoeuvres. Thirdly: You can probably get to where you need to be faster using a capital ship. In space the most important thing to bear in mind when working out how fast you can get from A to B is how much you can change your velocity (delta-V), which generally improves as engines get bigger. Depending on exactly what your engines are like you'll probably find that large monolithic starships are more efficient in terms of acceleration and deceleration and can therefore get to targets better, while star fighters need to be used in a similar manner to escorts for larger ships in naval combat (removing smaller threats that the main capital ship isn't designed to deal with). In that scenario your 'helicopter' class fighter is redundant: You've already got a capital ship. **EDIT:** As there's some disagreement in the comments and the OP has edited the original post, let me make my meaning absolutely clear here: I'm not trying to say that a capital ship will necessarily be more agile than a starfighter, I'm saying that unlike a naval carrier group/plane combo you will be able to get to your effective engagement distance faster in a well designed carrier than by relying on fighters alone. This is fundamentally down to the design constraints on a fighter vs those on a capital ship, notably that if the designers of a capital ship chose to they could simply increase the amount of fuel available to the capital ship, where a fighter would not have that luxury without sacrificing the manoeuvrability that it needs to perform it's role. This removes a potential use case for the helicopter as it's role is *already being fulfilled* by the carrier that was used to deliver a group of fighters (which must be short range in order to stay agile) to a target as fast as possible. Of course, all of this depends on exactly what your technology is like, what weapons you're using, where you're fighting and a hundred other historical or sociological reasons beside. So if you want to differentiate 'copter' class of starship from 'fighter' class of starship, go nuts. An example might be that star fighters use projectile weapons and engage in fairly close quarters combat where starcopters sit at a distance and use missiles. But fundamentally there isn't any real difference other than the names you give them. [Answer] # What are helicopters useful for today? Today, they are used to hunt submarines and engage small surface craft. 'Sub hunting' or anything like it, doesn't exist in space. So thats out. I you are a hostile (to the US) nation in the Perisan Gulf, and you want to take out an American warship, your best option (that isn't a submarine) is to swarm it with small ships. These small ships will either shoot large missiles (especially large relative to the size of the ship) at it, or just ram it while filled with explosives. For various reasons, a surface ship isn't great at combating these threats. Mostly, the angles of fire and visibility are constricted by both the horizon and the need for the ship's deck to be elevated several meters above sea level. This means that naval guns have to depress (i.e. elevation below 0) to hit small boats at close range. Helicopters, by virtue of their altitude, avoid this problem. A helicopter gunship, like a Cobra or Apache, can ruin whole fleet of small boats with a 30mm autocannon. # This doesn't work in space The problem is, in space the same limitations on surface ships don't apply. There is no simliar problem of constraint with either 'horizon' or a 'deck'. Capital ships in space should be able to deploy weapons in any direction in 3-d space. Given that they can mount more powerful weapons, and that these weapons have travel speeds of close to or at the speed of light (particle beams or lasers or similar), they should not need any help combating small craft, whether small boats or starfighters or anything. In fact, given advancements in computerized aim, I would suspect that starfighters would be nothing by shrapnel in a fight with a capital ship. In conclusion, there is no need for anything helicopter-like in a deep space battle. [Answer] ## The problem with fighters You will not have manned starfighters. In space size doesn't dictate maneuverability. A 2-person fighter can be as agile as a 2000-men starship. Taking maneuverability out of the equation it makes no sense to make small manned crafts. > > A Note On Space Combat In depicting combat in space, science fiction (movies in particular) long have conveyed rather simplistic models of WWI and WWII fighting. Tiny craft, for instance, are normally depicted as faster than large ("lumbering" is frequently the adjective) ships; this is indeed true, or can be true, on Earth, where conditions force trade-offs between mass/heavy weapons and speed/maneuverability. But conditions in space are not egalitarian. > > > For general expectations, sub-light ship speed would be limited by the size of the engine, if the types involved are equal, and by the mechanics of relativity which demand (at near-light speeds) great increments of mass/energy for tiny increments of speed. (There is also the problem of interstellar particles at high speeds turning the noses of ships into little atomic battlefields, to the misfortune of hull and crew.) > > > In space, ranges are unlimited by terrain or earth curvature, visibility is absolute, and surprise probably only strategically. In such conditions, the faster ship will be the one also with bigger and better weapons; engine performance will tie directly to range and breath of energy and field weapons. Evasive maneuvers carried out by necessarily shallow curves at even 0.1c speeds will hardly challenge sophisticated fire control and titanic-aperture lasers (free of planetary weight deformations, lasers theoretically can be of any size). The next time you watch Battlestar Galactica, ask yourself how well an F-16 would fare against an energy beam with a diameter of 2000 kilometers: in space, given quality, bigger is better. > *Lynn Willis (1979)* > > > You can't hide your heat signature in space. So you'll need to either kill the enemy faster, evade enemy fire or withstand it. As maneuverability isn't linked to size, fighters have no advantage here. Neither do they have the space for heavy armor or large armaments. A larger ship will do better. Now if you want to overwhelm your enemy point defense missiles could be augmented with a drone force. Drones can be more maneuverable than manned starships because they have no problems with sudden acceleration. ## Roles of a chopper So your chopper alternative is gonna be put against (large) starships and small drones. What does a chopper do? It moves material and personnel around the battlefield, quickly engages enemy targets like armor or is used to scout ahead. So lets look at those roles. Movement of material and personnel? Everything will have autonomous propulsion or it's ammunition. There isn't much to move around. Ships will move at high relative speeds dodging enemy attacks. There won't be any lone spaceman out there. Perhaps you could do rescue missions. But saving stranded spacemen would be something you do after the battle. Not a combat mission and any spaceship that can maneuver careful enough to not hit our guys will do. Quickly engage the enemy. Bigger ships have room for bigger engines and thus can do faster. It's not gonna be there faster then one of the larger ships. Perhaps you'd have a relatively smaller ship to be a smaller target but it's still gonna be a large craft, or a drone. Scouting? Well, given that there is barely anything to hide in space you can't hide your heat signature. Ships, unless inside something like a warpfield, are going to be detected well before weapon range and much before visual range. For this a drone would be more useful. It happens to be more expendable and can be more maneuverable. ## Summary *No, unless you make it a drone*. It still won't shift cargo during a battle but it will bring superior maneuverability. Smaller means smaller engines = slower. Mass has no relation to maneuverability in the vacuum of space. Thus a smaller craft loses another advantage. [Answer] Consider what uses helicopters and what uses fixed wing aircraft. You can deploy a helicopter off a small pad on the back of a destroyer or frigate, while fixed wing aircraft need a much larger launch/recovery platform. So in your space analogy a helicopter equivalent would be a small *manned* shuttle type craft that can be deployed by smaller ships, while fighters would be larger (possibly due to more remass, weapon systems, more life support for longer patrols?) and need a much larger base spacecraft. As for roles, the shuttle is what you use when you want to ferry personnel or supplies between ships, perform short ranged missions, etc. Sort of merging the helicopter and small boat roles in the wet navy. But also realize that 95% of these tasks will be better suited to remotely piloted drones/AI machines. [Answer] Close engagement and boarding, getting around to the other side of the behemoth, inserting boots into command centers, engine rooms, rescue, delivering medics, O2? [Answer] After reading several answers I think I might have a solution. It is based on several assumptions, but here goes. Let's say (as others have pointed out) you want to put the biggest engines and thrusters on your fighters, and also big guns. That doesn't leave much room for shields, and perhaps your fighters are better at outmaneuvering fire than absorbing it (assuming speed-of-light weapons aren't being used or aren't practical for some reason). Perhaps you want to protect your fancy capital ship with more than just its own shield, and this assumes it can't have several layered and/or decentralized shields. ### Shield Craft Well then a smaller craft at a distance from your capital ship could be precisely designed to have a powerful shield, and be only as maneuverable as your capital ship. Assuming a "Helicopter Pendant" is some kind of award for a human pilot, the question of whether it takes a human pilot or an automated system to implement shield craft might be another discussion. ### Side Note Theoretically your capital ship could come upon planets with atmospheres, and in this case it could be useful to deploy VTOL craft to explore it, or do other activities within an atmosphere where helicopter-type craft would be incredibly versatile. [Answer] While not an exactly equivalent spot to an actual helicopter, a subgroup of military helicopters (and aircraft) is actually featured in many science fiction universes. They are called [Gunship](https://en.wikipedia.org/wiki/Gunship). With helicopters specifically, they mostly fill two roles, with fixed-wing aircraft one: Heavy fire support (Heli&Fixed) or troop transport (heli). While not all of the helicopter gunships can transport troops, one of the more prominent gunships of the soviet and modern era is the [Mil Mi-24 Hind](https://en.wikipedia.org/wiki/Mil_Mi-24), bearing a mind-boggling rocket- and missile armament as well as machine cannons, it can also transport a medium contigent of special forces or regular troops into battle. The probably most-known fixed-wing gunship is the [AC-130 Spectre](https://en.wikipedia.org/wiki/Lockheed_AC-130), which bears different armaments of cannon up to howitzer calibre. The main similarity is the relative fire power to other support or even attack craft when air superiority is held. Similarly, I would see the role of Gunships in space battles, assuming that your universe sees this as feasible. Gunships would be less manouverable than fighters, but would carry a heavier weaponry as well as a potential small bording party. To get the most of these craft, you would have to, just as in the real world, take air control (or space superiority perhaps?) or at least be dominant enough so that the enemies fighter craft cannot intercept the more sluggish gunships before they can bring their armament to bear/get close enough to board the enemy vessel. Some Science-Fiction universes have done this to different degrees. **Battlestar Galactica** Two major vessels: The [Colonial Raptor](https://en.wikipedia.org/wiki/Colonial_Raptor) and the [Cylon Heavy Raider](http://www.hard-light.net/wiki/index.php/Heavy_Raider). Both serve support roles in the battle, albeit they differ a bit from each other. However, in that sense, both serve the roles of something akin to helicopter gunships very well. **Star Wars** The old Republic used the [LAAT](http://starwars.wikia.com/wiki/Low_Altitude_Assault_Transport/infantry) as a Gunship with Troop transport capability. It was used to land troops and provice air-to-air and air-to-ground support. Since its essentially a space ship, it could be used in support roles too due to its rather heavy armament, if air/space superiority has been taken. **Star Citizen** The [Redeemer](http://starcitizen.wikia.com/wiki/Redeemer) is a gunship much similar to the way both star wars and the real world handles them: A less manouverable weapons platform with many heavier weapons than pure fighter counterparts, it is also a boarding platform as well as a landing craft for ground assaults like the LAAT. **Ideas** Like other answers before mine, I can think of many other support roles a "helicopter equivalent" space vessel could assume. Some would overlap with AWACS and Bomber roles, some with pure transport roles. Some would have EWAR capabilities. I would say however that in this kind of setting, it is almost impossible to distinguish helicopter-like roles from those of other support craft. I mean, since everything is moving in space, "helicopters" would be the same as "assault boats", "gunboats", "Torpedo boats", "submarines", etc. There is no reasonable distinction to make here. I would therefore abandon this thought and just refer to "gunship", as you could group all of these together in one word without losing their meaning. **Side Notes** My examples assume you would have space battles like you would planet-based naval battles, which may not be realistic, but *fun*, at least from the perspective of characters in novels and games. The usefulness of each of these vessels depend on the state of your sides space superiority in the area of operation. the less control you have, the less effective your gunships will be. However, if you hold control, your gunships can bring much more firepower to bear. [Answer] ## Helicopter-like spacecraft would be useful in constricted environments. These may not be common in space, but there's no reason to think that they couldn't exist. Mostly, constricted environments will be those that surround large, man-made structures such as space stations, industrial installations, or exceptionally large ships. For example, a highly maneuverable spacecraft could be useful in an environment like this: [![enter image description here](https://i.stack.imgur.com/8YXKr.png)](https://i.stack.imgur.com/8YXKr.png) With multiple sources of cover, having a vehicle that can move around and exploit that cover, as well as effectively target enemies using that cover, could be very useful. That vehicle would effectively be your "space-helicopter". Space-helicopters wouldn't be used if the goal of the attacker was to destroy the space station/city/etc, just as helicopters aren't used to level a city to the ground, but if the goal of the attackers was to destroy pockets of resistance in a structure that they'd prefer to leave intact, something that can move effectively and hold its position in a congested environment would be incredibly useful. [Answer] As it was pointed out in previous answers, there is no direct analogue. But one can theorize tasks, which would be some way similar to those, which are solved by helicopters by the wet navy: 1) In a sufficiently low-tech setting kinetic missiles launched from ground on the other side of the planet, and placed on a retrograde intercept orbit could pose a serious threat to the spaceships due to their sheer orbital velocity of many km/s and because in the intercept phase they are only pieces of metal, hard to detect or stop. Therefore, military spaceships entering orbit around a possibly hostile planet would place some satellites to high (possibly synchronous) orbit, to have the full planetary surface observed, and provide early warning in the case of enemy missile launch (so they can change course in time.) These satellites would be a bit similar to submarine-hunting and sensor-carrying helicopters. 2 ) The other main use of helicopters is troop insertion and rescue. After the battle is over, and the starships have gunned the life out of each other, there are a lot of large pieces of debris on orbit. Whole ships, structurally largely intact, but disabled and their crew killed, are acting as space trash. But the victor's starships are unwilling to approach these. Which admiral would risk to loose his flagship in debris collision, or because of a reactor explosion on a nearby, wrecked enemy vessel. Instead they launch smaller crafts. These recovery tugs are propelled around by small thrusters. (Velocities were mached before the battle started) They carry medical equipment, plasma cutters, magnetic grappling hooks, light (pont-defense grade) weaponry, and xenon lances (fictional equipment to shut down reactors from outside.) They carefully approach floating debris, and cut the survivors out from the deformed hab modules (before they run out of oxygen) and accept the surrender of the enemy survivors (or murder them, depending on their ethics.) After the people were evacuated, they scavenge everything usable: fission, fusion, and annihilation ammunition, fusion control magnets, laser crystals, computer cores, nanostructural hull plating, hydroponics tanks, robots.. or whatever is considered valuable equipment in your setting. They also collect intelligence information: sample enemy armor and fuel tanks, record the holes made by allied weaponry, (to fine-tune the phasers for the next battle or to correct the targeting computers) copy the logs and memory units, remove the identification transponders, and collect trophies of the victory. In the last phase all the remaining debris is pushed off-orbit and left to burn up in the atmosphere, or (if necessary equipment is available, and the metals worth the extra propellant usage) is collected and compressed for recycling. 2B) Theoretically, the rule of planetary dropships (like First Order landing craft or LAAT/i in Star Wars) is also a bit similar to helicopters, and in some films, these are actually used as attack helicopters in the atmosphere, but I don't think, that in a more hard sci-fi setting, this is possible, since reentry capable troop transports would be designed to quickly deploy the units and evade enemy fire, not for hovering and close support, since they would be easy prey for ground based missiles. ]
[Question] [ Question inspired by Batman: Arkham games - although this trope is definitely not limited to this series, it is very widely (ab)used in various media. In Batman: Arkham, various mob leaders are excessively cruel, even towards their own henchmen. They will torture and kill their own guys whenever they fail to stop the Batman, whenever it feels convenient or sometimes even just on a whim, for no good reason at all. Ostensibly, it would seem such a behavior is not feasible at all. First of all, people are valuable - from the POV of a crime lord whimsical killing of their own guys would seem no more sensible than, say, whimsical destruction of their own firearms stacks. Even if people are viewed just as resources, no sane person keeps robbing themselves of their own property. Secondly, who would sign up as such a crime lord's henchman? If signing up as Crime Lord X's henchman does not even guarantee security from X, then, from the POV of a random crook, X is a terrible candidate for an employer and instead the crook should rather seek employment from Crime Lord Y who is known to be less excessively cruel towards his own people and who can be at least trusted not to be a threat towards those who are loyal to him. Therefore, it would seem to me, that the trope is BS and the Penguin or the Joker (who in the games behave in this way) would, in reality, be doomed to fail. However, it seems that real life does not confirm my conclusion. Stalin, for example, was known to behave in this precise way - not even unyielding loyalty towards him could guarantee safety from him. Stalin was, in reality, almost as dangerous towards his own people than he was towards his enemies. Yet, however grudgingly, I must admit that Stalin was very successful. Also perhaps it is possible that if crooks are used to such a treatment (that crime lords tyrannize them and kill them on a whim even if they remain loyal to their lords) then, if a crime lord arose who was actually valuing his own people, then the crooks would believe this to be a sign of weakness and turned against such a crime lord (instead preferring lords who keep killing them?) If and under what conditions is it viable for a lord to kill their own people even though the victims remain loyal? [Answer] # No Better Option Stalin will kill you if you betray him. He might kill you to make an example. He might kill you if the mood strikes. But whatcha gonna do? Sign up with the second most popular Grand Leader in the USSR? Scoff, let me know how that goes, champ. . . . You could always try to flee the country, but this is more dangerous than staying. If Stalin catches you he will definitely kill you. If you stay around and keep under the radar, he will probably not. You are in danger from Stalin. But your best option is to stay where you are. Your mobsters work the same way. They come in two flavours: (a) The droogs who are not known by name to their boss. They join the gang out of desperation. They have no better option. They are poor. Or their family is already in the gang. They are not worried about the crimeboss killing them because they never even meet him, and are too concerned with the danger from their day-to-day jobs. Heists, drug-running, murders, gang wars, et cetera. (b) The pins. These guys oversee the gang. They do not get their hands dirty. Their biggest threat is indeed the crime boss, but they are stuck in the gang now whether they like it or not. The boss knows them personally. If they run or betray him, they will be made an example of. Of course some Droogs become pins, but as the day-to-day danger drops the danger from the boss increases. They are always in a state where their best option is to stay. [Answer] ## A) Killing needs to be a norm, B) there should be a cult of personality C) the economic benefits of being in the uppermost echelons justify the risks What do Stalin, Beria, the Ottoman Selim I/Murad IV, all have in common? They arose in societies where a) killing was the norm, b) there was a cult of personality that justified it, and c) the henchmen had powerful material incentives to take the risk of being henchmen. In Stalin and Beria's case, they took a murderous tyranny where it was normal to kill subordinates and rivals, and took it to the logical limit. In the case of the Ottomans, you can track a series of loose norms that became customs and even laws surrounding killing rivals, failed servants, and especially, the siblings of the Sultan (not so much society at large as in the USSR). It actually became a real law that brothers of the Sultan were to be killed. In both cases, you had cults of personality that made crossing the Boss considered both a) wrong, and b) a death wish. You also had extremely unequal societies where obscene rewards accrued to the ranks just beneath the tyrant, which, coupled with ambition, provided a steady stream of replacement Politburo members/pashas and Viziers. These three properties ensure that: A) There is a tyrant. B) There is acceptance or eben celebration of the tyrant killing subordinates C) There are plenty of replacement subordinates. Edit: In response to comments, a cult of personality may emerge for different reasons but relies on patronage (see: point c) and a positive feedback loop with killing off rivals. In Stalin's case, he used his position as secretary to install cronies, then factionalism to kill off rivals and replace them with more cronies and eventually bypass the collective authority of the Politburo. In the Ottoman Empire, the office of sultan had a cult 'fairly earned' by a combination of achievements and ruthlessness, set by early conquering sultans like Mehmed II, who both conquered Constantinople and was a sadist. Each generation got more ruthless with killing their own family,while still governing effectively until after the practice was well established. "The Ottoman Centuries" is an easy popular history that is relatively pro-Ottoman but outlines the gradual but horribly consistant evolution of family murder as a practice within the royal family. [Answer] The Emperor [Commodus](https://en.wikipedia.org/wiki/Commodus) is a good example of a ruler who bumped off people randomly and suffered from delusions of grandeur. From the Wikipedia article: > > ...early in 192 Commodus, declaring himself the new Romulus, ritually re-founded Rome, renaming the city Colonia Lucia Annia Commodiana. All the months of the year were renamed to correspond exactly with his (now twelve) names: Lucius, Aelius, Aurelius, Commodus, Augustus, Herculeus, Romanus, Exsuperatorius, Amazonius, Invictus, Felix, and Pius. The legions were renamed Commodianae, the fleet which imported grain from Africa was termed Alexandria Commodiana Togata, the Senate was entitled the Commodian Fortunate Senate, his palace and the Roman people themselves were all given the name Commodianus, and the day on which these reforms were decreed was to be called Dies Commodianus. > > > Then he did something even really stupid: he caused his own domestics, his concubine Marcia, the chamberlain and the praetorian prefect to fear for their lives; they felt that they would be safer if he were dead. Marcia poisoned him, then he was strangled, as he was taking too long to die. Moral: never let those closest to you feel that they would be safer if you were dead. [Answer] # Have weak internal opposition and distracted external enemies. Stalin personally didn't actually order that many killings. He was fairly hands off and uncaring of what was happening. What he did was organize the security forces so that they had a certain quota of dissidents to capture. This meant that anyone vaguely suspicious got captured, but also a lot of innocent people got randomly swept up and killed. It was a very top down mass slaughter. This was only possible because Stalin had centralized power and their external enemies were distracted. There was no force that could effectively oppose him or cause problems and no external enemy able to take advantage of the weakness caused. I've seen you in the comments say it's not efficient- no, no it was not. Stalin did terribly in ww2, and Russia would have lost if not for massive loans of British and American equipment. But, so long as you have weak internal opposition and weak external opposition, then you can kill people pretty freely. Batman is the same. The police are very weak, there's a huge supply of poor men with minimal job prospects, and Batman is one man. For the most part the lack of serious opposition means supervillains can do as they want. They only really need to be careful if Batman starts pressuring them hard, or if they get in a gang war with another gang. [Answer] ## Rule by fear Ultimately, a system of rulership that we often see in history and that, at least for a certain time, works. Whether it is a tyrant or a gangster boss, the seemingly arbitrary violence is not entirely random, even against loyal, own people. It creates an essential, necessary element of such a form of rule: competition among accomplices. No one - whether a fascist tyrant or a Mafia boss - rules alone. A rule based primarily on terror is essentially dependent on accomplices, since other methods of imparting rule (laws, public discourse, ethics of responsibility, etc.) cannot come into play here. But these accomplices are also the greatest and most direct threat to the ruler. If they join forces, the ruler could be propped up quickly. Showing that arbitrary violence is possible even against the most loyal accomplices effectively prevents this from happening: Everyone does not want to be next. The (superficially) safest method is to please the ruler. By being particularly ruthless, by delivering the best news, by getting the best results. And above all: by betraying other accomplices on the same level - so that they become the next target of the ruler's displeasure and not oneself. A current example: the public dispute between the Russian defence minister and the boss of the PMC "Wagner" about who is to blame for the foreseeable failure of the invasion of Ukraine. **Why is it nevertheless appealing to be active in such an environment?** It offers the possibility of becoming incredibly powerful and/or rich yourself. An accomplice in the inner circle has opportunities that others do not have. While there is the possibility of not being lucky and losing everything, it is more likely (historically speaking) to be lucky while it lasts. And even if it is completely clear to an outside observer that things cannot go well, man's ability to suppress existential dangers is unbeaten. Likewise, such complicity offers more security than being more distant from the ruler. A commoner or a small street thug without contact to the ruler has no possibility to influence him (especially: by betraying others from the inner circle) and has a higher probability of being hit by arbitrariness. [Answer] ## Misdirection Use the same technique used in real life--create an enemy that's scarier than you are, and present your tyrannical rule as the only reliable protection from that enemy. Pick whoever you want--Jews, Blacks, and Communists are popular options, but immigrants, fascists, liberals, conservatives, nazis, or any available minority can do the trick. The key is to hype them up as at least as ruthless as you are, but malevolent as opposed to your benevolence. This draws a reaction like "They're all bastards, but this bastard is **our** bastard." As long as people feel threatened more by your bogeyman then by you, they'll rally behind you. ]
[Question] [ In my world, because of how difficult the dark lord antagonist is to kill, he was permanently trapped in a weird substance. However, centuries later, he gets out and he is free. He awakens now in my world's equivalent to the 19th century, and he is from the 17th century. People are shocked that he is back and alive, and now he has to regain his kingdom. What would cause the people to allow him back into politics, even though he is a literal dark lord covered in armor? While this may be for one dark lord, this is meant to dark lords in general, because this happens a lot in the lore, but in different parts of the world. Notes to mention: * He was originally from the Renaissance era, and is now in the Victorian era * He was originally an absolute monarch, though now the kingdom is a constitutional monarchy * The kingdom is based on the Ottoman Empire * He cannot influence with "evil powers", because there is no such thing, his powers are mainly based around durability and near-immortality (he can live forever, but can get killed. Extremely difficult, but not impossible) [Answer] Because when he was the ruler, the kingdom was at its peak in terms of global power. Now it's a bit-part player bending to the will of the new upstart kingdoms. The local people are always hungry and cannot afford to feed their families. The people in the country dream of returning to their rightful place as the greatest empire in the world, with prosperity for all. Who better to lead them into this glorious future but the man who did it last time? Nobody alive remembers how cruel he was to his own people, only that they used to dominate their rivals. For a real world example just look at Putin's campaign to reignite the glory of the USSR, just replace Putin with a literal reincarnation of Stalin. [Answer] # The General Population is Suffering [![enter image description here](https://i.stack.imgur.com/aVvUe.jpg)](https://i.stack.imgur.com/aVvUe.jpg) Most advanced 19th century countries had huge gaps between the wealth of the elite and the wealth of the general population. Workers worked in factories and mines and on farms 12-15 hours a day for starvation wages, with no worker rights or unemployment benefits. Even [children down to the age of 4](https://www.ducksters.com/history/us_1800s/child_labor_industrial_revolution.php) worked long hours in unsafe conditions, while the elite (nobility, merchants and factory owners) lived in huge estates without having to work much, if at all. Starvation and abject poverty were a fact for at least half the population. Into this comes the Dark Lord reborn and promises the suffering population better times if they rise up against the elite and put him in power. The Dark Lord also galvanizes nationalists who dream of a return to the glory when the Dark Lord first ruled and the "Ottoman" Empire was a force to be reckoned with. This unholy alliance of the disenfranchised poor and middle-class nationalists scares the elite, and many of them swear allegiance to the Dark Lord for fear of losing not only their wealth, but also their heads. Such things have happened many times in the past: Large shares of the population see no future in the status quo and are willing to follow any demagogue who promises something different. They may not entirely trust the Dark Lord, but at the very least he will upset the status quo, and that is something, after all. Think of Hitler, the Russian Revolution and today's nationalist populists on both sides of the Atlantic. [Answer] **Apologists and Conspiracy Theories** “The lying media wants you to think the Dark Lord was evil! He was only dark in the sense of his handsome swarthiness! He didn’t put people into slavery, he merely promoted hard and honest work for all! Genocide? You really believe that the dark lord could kill millions of people and burn all the bodies! What nonsense!” In the real world people make apologies and work very hard to rehabilitate absolutely horrendous dictators. The Holocaust is incredibly well attested yet there are thousands of people who are Holocaust denialists. Stalin has a large fan club in Russia and to a lesser degree in other Former Soviet States, and he killed millions. [Answer] **Ambitious climber sees benefit in an alliance with the Dark Lord.** [![Tarkin and Vader](https://i.stack.imgur.com/3sBZ1.jpg)](https://i.stack.imgur.com/3sBZ1.jpg) The risen Dark Lord is creepy. No-one knows him any more. His accent is strange. But the Dark Lord back in the day was not always a Dark Lord. He worked his way up. He is immortal and he is fine with the long game. He will work his way up again. There is an upstart schemer who perceives that allying himself with the Dark Lord will be advantageous to himself. He is not afraid of the Dark Lord because he is a powerful person himself and the Dark Lord is not what he once was. This schemer is no dope and his calculus may be correct. The Dark Lord is not egotistical. He is fine being wingman. He will not be wingman forever and he can afford to wait, and learn about this new world as he serves. His time will come. Again. [Answer] "good old times" feeling is a powerful driver which often cancel other more rational thoughts. For example in countries of the former USSR the worsening of life standard has lead to an increase of nostalgic feeling toward the Stalin era, Argentina has had a few waves of Peron and Peronism guiding the country and Italy has periodically politicians claiming that Mussolini did good things and was a good leader. Like Clinton's staff said during his run for the presidential seat, "it's the economy, stupid!". People can afford being rational when they are not hungry. If instead they are, many would trade higher ideals for materials benefit. [Answer] For all the same reasons we see currently. * Some people/families were benefiting from the Dark Lord being in power and would want to be back in power/have more power. * some people agreed with "his" ideologies. Similar to some people saying Hitler kind of had a point murdering gays, Jews etc and that we should continue that kind of stuff. This has some grey areas as some people might not agree with the wholesale murder but do agree with other parts of the ideology. * some people dont believe it was that bad. "Nah there wasnt a holocaust", "the victors write history so he looks way worse than he was". * some people point to what went well. This is basically what is happening in China: while people might not agree with some parts of Chinese policy (say the "cultural re-educationcamps" that outright torture people just for being a certain background many people say "well overall its going better and its not like everyone else is perfect"). An idea of "as long as you keep your head down and do your thing you can live happily with virtually no limitations" is fairly common. So why not take on this Dark Lord? He had a great economy, a swift and (mostly) just justice system and a solid political system (as far as they can tell). Its not like this King has been an angel! [Answer] 1. He Is needed to protect their country from external threat. As we've seen he already has super power so hes very valuable as a soldier. And if he is anything like other dark lords then he probably is also a skilled general. Someone times the best way to grab power is to point out that the other side is even worse. If a foreign Invader is coming the people just might see the dark Lord as the lesser of 2 evils. 2. Political instability and Civil War. What could make the freedom loving Romans literally threatening to revolt if Augustus did not seize power? Generations of political instability, two brutal purges and Civil War. After years of constant bloodshed Having a strong man you can keep relative peace even if he is a tyrant then perhaps a tyrant doesn't sound so bad. 3. Time passes and people forget. Imagine if you were to find a book title " The upside of the Third Reich and Hitler ". I'm sure you would be horrified as you should, But the sad truth is that book will be written. Not today, not in a 100 years, probably, but given a 1000? Consider this Hitler killed millions of people for , At least according to his own propaganda, The good of Germany. Genghis Khan also killed millions of people, The reason To get him and his allies more stuff. Yet Historians are full of praise for the mongols invasion. They talk about how they connected the East and West and how it jump started technology and trade. We would never accept A resurrected Hitler's attempt to become president of the United States, But a resurrected Genghis Khan ? We probably at least let him run if reluctantly. If time enough has passed since the dark Lord's death Then perhaps people Don't consider him as dark as the use to. Maybe some of the worst stories are dismissed as anti dark Lord propaganda or the history of the winners. Maybe historians have begun pointing out the benefits to the dark Lord brought during his reign. [Answer] **He's rich** [![enter image description here](https://i.stack.imgur.com/lz7JZ.png)](https://i.stack.imgur.com/lz7JZ.png) Before being trapped, he stashed much gold and artefacts in hidden vaults around the place. He can use the wealth to hire advisors to make him look good. Buy a knighthood or a barony. Plenty of poor nobility you can get titles off. Buy businesses to amass a financial empire, control trade and commerce. Once you have enough power, you can get into politics as people will be afraid to upset you. Muhahahaha [Answer] ## Chaos One Dark Lord is better than a thousand feuding petty tyrants and bandits and sorcerers. Oppressive taxes that are at least consistent are better than having everything you own seized at random intervals. Better to have the prettiest maiden in town taken to his harem than for different bandits to abduct a maiden every month. Heck, one overlord might even mean you could follow his laws. [Answer] Welp, there the obvious answer based on the premise of working within the system ... ### What is Not Forbidden is Allowed Technically, there is nothing preventing the awakened Dark Lord from entering politics. They have, as of now, committed no crimes nor have they engaged in illegal acts as defined by the laws of the new constitutional monarchy. So long as they are aware of the laws and follow them, there is no reason why an awakened Dark Lord can't enter politics. Believe the people who went over the laws intensely to try to disqualify the Dark Lord -- they found nothing and they dig through *everything*. Oh yes, it will possibly anger people immensely -- after all that's a Dark Lord! But the rules need to apply to everyone equally, much to everyone's annoyance. Odds are that the new constitutional monarchy never considered the Dark Lord regaining their freedom so have never put the appropriate laws into place to safeguard the system from them. Term limits likely wouldn't be considered as that might weaken their own power in politics if they have to retire after so many years. ### Difference in Opinion Given the difference in both the time they ruled and the style of government, the Dark Lord will have different ideas of how to run a nation than the rest of the politicians. On the surface this is a net neutral as they are only one person initially. Even at the head of a major party in the future, it should still be neutral as there should be factions that have differing viewpoints. Some of their initial views might not be as popular, but theirs was a different time. Harsher justice was needed, and people needed to rule with more power then they do now. But the seeds of those ideas, the ideals of how the Dark Lord may have ruled, are still potentially valid even two centuries later. This is not to say that they should be adopted wholesale, but an avocation of a stronger government on certain things is not necessarily wrong. Even though their ideas are 200 years out of date, but so long as the Dark Lord can adapt to the changing times in thoughts and deeds, then they can mold the new nation into something that they want to take over and reclaim. ### Perspective of Time The returned Dark Lord want control of their kingdom back, sure. But they can wait -- they are immortal until killed after all. They do not need to reclaim their kingdom tomorrow. They don't even need to do it in a year. They have the option of planning things out over the span of decades and adjusting those plans when the global situation changes. A slow and patient game will suit them best and plays to their strength of longevity -- they can simply outlive their opponents. It's about molding the nation into a kingdom worthy of ruling. ### Alternative Plots Everything above operates on the premise of entering politics to work up the system to eventually rule. To work within the confines of the constitutional monarchy to amass power and retain it. And done correctly, it could work. Politics could be a way to gain prestige to begin to hobnob with royalty. Some words here, some money there, and a strategic assassination, and they could be at the top of the monarchy. And as they don't die under normal circumstances, their reign will last centuries. Then the issue becomes how much power has the monarchy given away to the constitution and how could they reclaim it. Same issues, but from the other side of the political system. This doesn't even get into the murkiness of the fact that as a previous monarch, they are Not Dead. Technically, their rule has been usurped by those that overthrew and sealed them and they could attempt to make a case of it. They might even win depending on how the laws were written. [Answer] He's a Dark Lord to most of the modern world... but he's a hero to his own people and had some impressive reforms that he spearheaded for there own improvement. It's just that his reputation around the world was due to his very aggressive foreign policy. This is not uncommon among several real life rulers with hated reputations. The best example is probably Vlad III Drăculea who's reputation for being a very bloody 13th century leader inspired the titular villian of Bram Stoker's novel "Dracula." But in his native Romania, Vlad the Impaler is one of the most celebrated heroes of the nation, where his barbaric prefered method of slaying his foes was mostly used on the Turks... who would have done much worse to the majority Christian Romanians who refused to convert to Islam if they got control over Vlad's holdings. Genghis Khan and Atilla the Hun are still heroes in their modern homelands of Mongolia and Hungary respectively, and Pablo Escobar is still beloved in Colombia, where he used much of the wealth of his drug empire to help local communities. Your Dark Lord could be similarly popular. Sure, he was a warlord... but he improved education, helped the poor, provided for orphans, rebuilt critical infrastructure and rebuilt it better, increased the rights of his people, reformed the peerage system, granted religious freedom, reformed the courts and protected the rights of the accused, ended public executions in the gladiatorial pits, patroned the arts, and now that he's back in the 19th century, will not only set up the railroads, but make them run on time! Sure... he's terrible on the international stage, but look at what he can do for you once he's invalid your terrible backwards land. [Answer] ## Ummah versus Sultan or other factionalism The Ottomans used to have some pretty gnarly court intrigues. Aside from scheming by royal family members, viziers, and court officials, they also had a fairly meddlesome Islamic clergy/ummah/judiciary. Now, if your Dark Lord ruled an Ottoman-like Empire for centuries, you can bet that at least a significant proportion of the religious leadership supported him at one point or another. Since his downfall, he has been condemned as a heretic on certain grounds, but a similar heresy is now in vogue, and a large part of the ummah has reassessed the former Caliph, noting his former military victories and political unity. There's also the possibility that the Janissaries remember him fondly, having been soldiers under him, and their wealthy and powerful descendants support him as a result. Either way, you need a faction that did well under him that has recently emerged as a major political player and has a bitter struggle with the current rulers. [Answer] ## The Dark Lord was a Progressive Back in the day he was a very intelligent and well traveled interlecttual. This was what gave his his immortality. However, he discovered other things as well. He saw how decadent aristocrats and old power structures stifled prosperity and had studied why city states were so unreasonably effective historically. He had seen "primitive" democratic societies whose people seemed to be filled with energy. Thus he decided to change his own nation. He took power, purged the clergy, the nobility and the guilds and set up more bottom up structured in their place. Land reforms and irrigation projects, public education, free trade and the like. Perhaps he banned slavery or broke up an ethic caste system. He was beloved by the people. However, an alliance of surrounding kingdoms brought him down in the end and most of his reforms were undone. His atrocities in removing the old power structures were exaggerated (though employed a rather brutal strategy of executing his enemies and their families publicly or something like this). The was painted to be dark. However, his policies were considered to be successful and his memory could only be tainted so far. Current day reformists see him as their prophet or spiritual founder. Kinda like Karl Marx for the Communists. Thus, **he has many ideological supporters in current day politics.** [Answer] ## His successor turned out to be a corrupt liar 200 years ago the leader of the group that trapped the Dark Lord took it upon himself to become his successor. But he didn't free the people, he was just as power-hungry as the Dark Lord. As the new leader he became known for running a corrupt government and used absurd levels of propaganda to control his people. The new leader had history books burned and rewritten with fake stories to make him and his ancestors look heroic. All that is left of the country's history prior to the Dark Lord's trapping remains only in the memories of those who were there to live it. 200 years later the Dark Lord returns, and no one is sure if the stories they heard about his evil 200 years ago were true or if they were lies from his successor. They decide to hear him out and give him a chance. ]
[Question] [ Cheaters are considered to be inferior humans with defective genes and just like mentally ill people and individuals born with various handicaps are eliminated from the gene pool. Capital punishment is used to erase adultery and purify society from individuals born with the cheating gene. This is eugenics by extirpation of the weak and the wicked. Much like the story about Spartans from Plutarch, Life of Lykourgos. However the society in question is not really advanced when compared to the modern world but it is indeed resembling of ancient Greece and Egypt. No electricity is available and neither is magic, but I still want the court to be certain that they are punishing the right guys. **Question**: how can the court tell for certain that someone is actually a cheater and they are are not dealing with a false accuse? [Answer] This was the original purpose of chastity belts. Example usage: * Anyone in public without a functioning, locked, chastity belt is assumed to be an adulterer and promptly stoned. * Spouse holds the only key. A responsible relative holds the key for unmarried adults. You can see that this makes family politics and individual freedom all tied up with sexual control and kinky dominance and ewwww. Of course, to be fair, ALL adults must wear the silly things. What will really happen is that rulers will create a double-standard, where one (wealthy, powerful) group don't need to wear the belts after all, while everybody else must wear the belts. All the illegitimate offspring will simply be claimed as legitimate. After all, who's going to stop them? [Answer] It sounds like you're looking for an *accurate* way to find an adulterer... I'd say, a court system like ours might be in play. Witnesses, testimonies, etc. If you're leaning more on the "doesn't have to be accurate" side of things... I'm thinking, what did they do in witch hunts? It was all manner of irrational things. They were assumed to have magic, so logically a magic user would survive drowning right? Hence, tie a brick to her ankle, sink her, see if she dies. I'm thinking for adulterers, send someone appealing their way, if they bite, they're an adulterer and are guilty. Or maybe they do something like check for STDs, I guess that's one of the only tangible things I could think of that they might be capable of, but we know this method would be extremely faulty. [Answer] > > No electricity is available and neither is magic, but I still want the court to be certain that they are punishing the right guys. > > > With human biochemistry, that is impossible. You must make do with "reasonable belief" and the possibilities of missing, mistaken, hateful and bought witnesses. Even keeping everything under lock and key would not be enough, because keys can be duplicated, locks can be picked (we're in a low tech milieu, remember: skill and a hardened iron pin is easy, Bowley 543 padlocks are not), and anyway the key must be in someone's possession, and that someone can be bribed, convinced, fooled or burgled. (I half-remember a joke about a village where all women wore chastity belts and half the children looked like the blacksmith). And finally of course "cheating" does not necessarily imply full standard intercourse (anyway, having (ever) had sexual intercourse cannot always be detected by medical examination - folk tales and traditions notwithstanding). But, for specific (i.e. physical enough) values of "cheating" and with some fancy handwaving, what you want could be possible. Let us start by supposing that these people have a weird and ruthless immune system, making them resistant to most pathogens and actually at risk of immune over-response. This would ordinarily also have the side effect of almost guaranteeing infertility, since the newborn would almost never be immunologically compatible with the host. So, a backdoor evolved that specifically allows matings. Once the mother's immune system has been "primed" to recognize and tolerate the father's antigens, the newborn child will also be protected and yield no reaction. This priming would happen even if no pregnancy is sought. Just having (enough?) intercourse would be sufficient to start the reciprocal adaptation. And this adaptation having taken place *can* be detected. We could have this work through pheromones, so that *whatever* you do while close enough, provided that both parties are consenting, properly excited, and breath each other's pheromones, will result in them being identifiably marked. This might also somewhat help in explaining the strong stigma against cheaters. A "loose" lifestyle could very soon send the immune system completely off kilter, resulting in several nasty, obnoxious and possibly even life-threatening side effects that have permanently associated "cheat" with "abomination" in this people's culture. Cheat three times in a row and die of a cytokine storm - God's way of enforcing chastity. Lifelong pairings *must* be the norm, and several complex medical rituals and "cooling off" penance periods have to be completed to allow the few divorces and especially re-marriages of widowers. It is also quite easy to imagine a rough immunoassay being possible and capable of determining whether someone's immune response is still copacetic or whether some *confusion* has ensued. For example: mixing the suspected cheaters' bloods in a vial with saltwater and some juices might show a fast haemolytic reaction, indicating that the two have had no intimate contact, or might show no adverse reactions at all, indicating that the two immune sets have already been somehow introduced to one another. This could provide the required "certainty". The "reciprocal arousal" requirement can also be used to identify cases of nonconsensual sex (and therefore, unconveniently for society, arranged marriages - which in a low-tech, probably agriculture-based culture would be quite common, unless inheritance laws were redesigned). If A reacts to B but B does not react to A, this means that however you choose to call the fact, however things went, B raped A. [Answer] So there are hundreds of REALLY bad ways used in the ancient world to prove guilt, but only one way that was usually accurate, and that was the use of impartial witnesses. If you suspect a partner of adultery, instead of catching her in the act yourself, you would need a person with no loyalty to either party to catch him/her in the act. Many ancient civilizations had some variant of police forces: Athens had civic slaves called "rod-bearers". Sparta had citizens who were both judge and law enforcement called "ephors". Rome had profesional policemen/firefighters called "vigils". It does not matter what model you go with, as long as your civilization has some kind of publicly accessible law enforcers, you could simply have them do house checks if you think your spouse is being unfaithful. If an officer does a house check, and your spouse is with someone they should not be with, they arrest the guilty and bring them to be executed. There is of course still the issue of bribing the police to say you spouse cheated on you, but there is really no legal system where police corruption is not a problem. --- Another possible solution which would weed out adultery genetically would be to simply kill any child that does not look like the father. Human infants almost always resemble thier fathers more than the mothers; so, it's usually pretty easy to tell by looking at a 1 month old if the daddy is actually the daddy or not. By killing off the products of adultery, you may not prevent people from cheating who are already wired that way, but you create an environment that selects against those people from having babies out of wedlock which would make monogamous people more selectively fit which could lead to more monogamous future generations. [Answer] For some cases, but unfortunately - not all, you might have a secret order of tempters/investigators, who could lure the supposed 'cheater' into a trap by seducing him and catching him right before a 'supposed' act of cheating on the investigator, who at the end, turns out to had been just an actor. Perhaps the judgment/execution/assassination could be accomplished on the spot too. It could work for the less romantic-type acts of cheating, but not for people who just want to start a new/second relationship, which would still be an unresolved issue. In this case, a standard investigation could have to be issued. It also can be secret and unofficial, such as the work of a spy, with the use of a silver-tongue to befriend the target or its family, to gather direct answers when possible or simply less-vocal clues. This secret order can also add some strong sexual stimulant (think aphrodisiac) that might increase the target's urge to act on the desires. The target would be under constant observation and investigators would simply follow, once it's necessary and catch the prey 'in the act'. If I've any more ideas, I'll edit the post. [Answer] Obviously the society is based on bad science, and adultery is a legal/social construct rather than an objective reality, so the whole things is doomed to fail from an objective point of view. However, this rarely matters to those involved. Like witch-finders, Nazis and racists, the legal authorities only need a system which satisfied them that it picks out the 'guilty'. Typical methods include torturing people to get a confession, or a divinely-guided test like those used to identify witches. Important to note that even in our modern society we have no way of determining whether anyone is absolutely guilty of anything -- appeals are always possible. [Answer] After a person is wed, the joined people are assigned a unique color paint that they ethnically, ritualistically and as a matter of civic pride paint their genitals with. If your paint shows up where it’s not supposed to, you out playa! [Answer] You can not deal with this question until you deal with rape, and with sex outside of marriage in general. How do you distinguish between a willing adulterer, a person who fraudulently claims they are single, a person who was raped, a person who just claims rape, a willing adulterer who then claims rape in order to have someone killed, date rape, and so on and so forth? And, of course, there is always the 'I changed my mind, after the fact' conundrum. A person who was originally completely willing, regrets the experience afterwards and then convinces themselves that it was actually rape after all, in order to protect their own ego. And exactly what does 'completely willing' mean, when you are dealing with hormones, intoxication, mental illness, power coercion, financial incentives, false promises, and other variants that diminish 'free will'? The long and the short of it is, unless your society has mastered the art of mind reading an involuntary suspect, the subtitles between rape, adultery, and deception are just too variegated to ever have absolute certainty. And even with absolute certainty, the shades of grey are so infinitesimally deviant that only some form of legal document that ascribes 'sexual privilege' to a couple, outside of which no matter what the circumstances, it is adultery and thus punishable by death, is the only way to ensure the genetic results of an adulterous relationship are not passed on, including those generated by rape, fraud, drugs, and other nefarious means. But the last point begs another question be asked: Is it the adulterous act itself that is being addressed as the criminal act (the assault to the concept 'this person is my exclusive sexual possession, someone else stole it from me and must be punished') or is it the act of procreation and of actual genetic transference that is to be avoided, in which case the only issue would be the parentage of the fetus, and thus would change the focus to the determination of parentage (even if by rape or otherwise)? Of course, there is the small matter of a claim to 'immaculate conception'. [Answer] Cuff spouses together. People that always together can't cheat on each other. You can't sneak out of your window to have a date with someone outside your marriage if you have to bring up your spouse along. This doesn't stop a couple of having consensual relationships outside their marriage with other people, but then it isn't cheating anymore, is it? Sure, this technique introduces a lot of problems on the society, but those problems might be worthwhile to explore. [Answer] A gross way of doing things: ## By selective fungal infections. This world has several benign, harmless types of fungi that grow all around the place and can be safely grow on human skin without any risk for their host. They can be used to create colorful tattoos, mark families, and so on. Those types of fungi can interbreed, giving rise to new types of color - mix up a blue fungus and and a red fungus enough times and you'll see the rise of purple fungi eventually. So, during marriage, a couple picks a specific type/color of fungi and ritualistically infect each other's genitalia. The thing will remain there and color their private parts for the rest of their lives, with their lovemaking serving as a way of exchanging spores and keeping them on the same "color". If one of them cheats, it will bring spores of a very different color to their culture, quickly changing their own original coloration. The one that didn't cheat will know for sure what happened, and then can bring up their spouse to justice. [Answer] **Honey Traps** From your context the aim seems to not be to *prevent* people cheating on their spouses, but to identify the people who might be tempted and eliminate them for crazy genocidal "breeding a better human" reasons. So just hire a load of attractive people to go around looking for romantic relations with people, then kill anyone these tempters manage to bring into their bedrooms. The only real source of un-wanted executions in this system would be corruption on the part of the tempters and temptresses, the might occasionally decide that the landlord who was mean to their sister or something needs killing even though he wasn't tempted. But law enforcement officials acting beyong their remit is a universal problem and not unique to this law. --- Final thought: why kill them? If the goal is to stop them breeding then castration also works: and might well feel more appropriate to the crime. [Answer] You can't. But what you can do is **create a proxy for adultery**, and tightly control *that*, instead. The ideal proxy is **contact between men and women**, because no contact = no adultery. After all, contact between men and women is *much* easier to police than physical intimacy. Interestingly, to limit contact between men and women, you only need to limit the freedoms of *one* gender. And, by "one gender", I mean women. Historically, in the real world, it has invariably proven *much* easier to limit the freedoms from women than of men. I'm told that it has something to do with reproductive economics, with power, and with tradition... but you can have whatever reasons you like in the world that you're building. To limit the freedom of a gender you typically need rules. In fact, you need several kinds of rules. First, you need Enforcement Rules. These are intended to convince people that: 1. These rules are for the protection of women 2. These rules are sacred 3. These rules are tradition 4. These rules are for the benefit of all society Second, you need Punishment Rules. Something like: 1. If any man or woman breaks these rules, they will be punished. They will be tortured and put to death by the community, in a public place. By flogging, stoning... something brutal, anyway. And then you need Separation Rules. They need to say something like: 1. Females over 10 years old must not go out alone 2. When females venture out they must be accompanied by a brother, father, husband, or another woman 3. A female accompanied by one other person is to be looked on with suspicion. Such a woman is shameful, although leeway is given if her circumstances allow. A female accompanied by many other women is a credit to her community. She is to be highly esteemed. 4. It is the duty of all females to accompany either women when the go out. 5. If a woman lives alone, or there is nobody in her household who can act as her chaperone, she may travel alone to her nearest female neighbour 6. If a female is seen with a male who is neither her father, brother, nor husband, then both male and female will be put to death 7. When females go out, they will be covered up. Their face must not be visible, neither their arms, nor their legs, nor any other part. Finally, you'll also need Marriage Rules. A society still needs men and women to meet and marry, so you need something like: 1. Elderly women will act as matchmakers and chaperones, so that men and women can meet and marry 2. No divorce. Ever. On pain of death. You also want to include a couple of Random Rules (so you know that an ineffable god is involved, somehow). Of course, you can still put adulterers to death if they're caught by eye-witnesses. (Again, it appears that it is is often easier to catch women in the act of adultery, than it is to catch men; a well-know example being [the woman caught in adultery in John's Gospel](https://en.wikipedia.org/wiki/Jesus_and_the_woman_taken_in_adultery). Perhaps this is because people are more likely to turn a blind eye to male adultery. Perhaps it is because, when "evidence" turns up 9 months later, it points very clearly to a specific woman, but not so clearly to any particular man). **Disclaimer** My intent in answering as I have appears to have been misunderstood by at least one commentator. Let me be crystal clear: I am *absolutely not* promoting the "keep women under lock and key" approach as a solution to any real-world problem. In the *real world*, I find such an approach **utterly** abhorrent. Just as the OP is interested in a *fictional* world where adulterers are punished, I am proposing a *fictional* approach to bringing about a (more-or-less) similar result. Handled well, the *fictional* oppression of any group in society can drive moving narrative, and can underpin compelling high-stakes drama. At the same time, *fictional* oppression can be a great vehicle for thought-provoking social commentary. It can encourage debate, and (I hope) it can help create a cultural environment where positive social change is possible. I'm thinking of Malorie Blackman's Noughts and Crosses, for example. More pertinently, I deeply admire the way that Margaret Atwood set [The Handmaid's Tale](https://en.wikipedia.org/wiki/The_Handmaid%27s_Tale) in an *extremely* misogynistic society. She has my admiration, *not* because I *endorse* the society that she wrote about, but because it drew my attention to the appalling mistreatment that some women face *in the real world* (and because it enabled her to tell a rattlingly good story at the same time). I hope and pray that I am a better human being for having read Atwood, Blackman, etc. and that *fictional* oppression can be a vehicle for reducing oppression in reality. [Answer] One clear-cut indicator is **Pregnancy** Assuming there's a male and a female, and all the cyclic timing lines up, and biology takes it's course, there's a bun-in-the-oven that becomes more obvious as time goes on. Downside to this is that it confirms **what** happened, but in no way proves the **other** party's identity. Depending on the needs of your plot, this might be resolved when the birth occurs, and the baby comes out with X coloured hair, same as the purported adulterator when the woman's spouse has a different colour. Downsides, all babies are ugly and look like neither parent. This fails if a pregnancy is not possible because of any-number of reasons. And timing - babies take 9 months to produce, so any adulterous claims might take that long to be resolved. --- Edit - this has almost no bearing on identifying the male. [Answer] **Hammurabi is *way* ahead of you all.** Hammurabi's first three laws: 1. If any one ensnare another, putting a ban upon him, but he can not prove it, then he that ensnared him shall be put to death. 2. If any one bring an accusation against a man, and the accused go to the river and leap into the river, if he sink in the river his accuser shall take possession of his house. But if the river prove that the accused is not guilty, and he escape unhurt, then he who had brought the accusation shall be put to death, while he who leaped into the river shall take possession of the house that had belonged to his accuser. 3. If any one bring an accusation of any crime before the elders,and does not prove what he has charged, he shall, if it be a capital offense charged, be put to death. Basically, you can't always prove that the adultery occurred, **but you make it so that if the accused can prove their innocence, the accuser will be killed**. *This will really cut down on the false accusations!* Especially since all it takes is one reliable witness willing to back up an alibi for *either* of the accused. Accusers if they're smart will only bring charges when the offense is absolutely undeniable. [Answer] On the assumption that it is only male-female cheating that is to be punished (since this is the only way that a cheating gene might be propagated to the next generation), we can achieve this by segregation of the genders: All women live apart from all men other than their juvenile male offspring. Men and women live in seperate walled areas into which no mature member of the opposite sex is permitted to enter unescorted. Juvenile males are sent to live with the men at the age of 7. All interactions between men and women take place in a designated walled area within which no concealment is possible, with no clothing permitted. All business, including copulation, takes place in public with multiple witnesses assigned by a roster. All people are permitted to interact with each other in the areas that they are permitted to enter without an escort. Assigned witnesses are watching only for unauthorised copulation or a person wearing the wrong jewellery (see below). When married, each partner receives a lockable item of jewellery that only their partner can unlock, that carries a highly visible pattern identical to that worn by their partner, but is otherwise unique. A mature person being caught outside any of these areas in company with a mature member of the opposite sex to whom they are not married without a sufficiency of chaperones or witnesses is considered to be cheating. [Answer] If you want to get cruel and oppressive enough: 1. All sex must occur with a certain level of supervision or at least an OK from the authorities. 2. Any babies that are born but were not conceived in this manner are put to death. Now while you might argue that the babies are unfairly punished for the crimes of (one of) the parents, it still achieves the stated goal of removing the "adulterer's gene" from the gene pool. Not without its faults admittedly, but I'd imagine no system of justice in ancient Greek / Egyptian time is... [Answer] As others have said, this would (should) play out similar to witch hunts. In cases like this, guilt is determined not based on physical evidence and investigation, but on what those in-world place their faith in as being "sound" sources of truth. Given the context of the world you have here there are a number of things that could fit this criteria and the technological limitations of your world. I would combine many of these things as we are after all talking about removing the judged party from the gene pool—serious business indeed. 1. **Eyewitness Accounts**: Generally part of every trial. Perhaps one neighbor has witnessed the suspected adulterer leaving/returning at a certain time every day, while another has seen our suspect with another person in public. In situations such as this (at least in our own human history), the accused party generally is responsible for gathering their own witnesses to testify on their behalf. 2. **Physical Evidence**: Items such as undergarments would be an obvious form of physical evidence. Given the state of technology, it would make sense to use dogs or a similar animal with good scent to provide this evidence. You could really take this idea and run with it. Perhaps the courts use specialized hounds for different eugenics cases. If the person is caught in the act/soon after, having an "Adultery Dog" sniff the crotch of the suspected party could provide some insight into whether or not they are guilty. If some time has passed between the event and the trial, you could use witness testimony to have the dogs sniff out if the suspect has been at a certain place, in someone's room, in their bed. This could also be an ongoing patrol situation, where police roam the streets with dogs, each trained to catch a certain type of degenerate. An "Adultery Dog" might hit on a man walking by for example if they pick up the scent of two different women on that man. This is a very technologically simple way to set up a surveillance-state of sorts that could provide real-time insight into who is doing what. Also, a snarling dog can be a pretty good deterrent by itself. Perhaps there is some healthy fear of specialized "Eugenics Squads" that utilize dogs to detect those that need removal from the gene pool. ]
[Question] [ In my world Mars is fighting Earth. the problem is what would they (Mars and Earth) use for orbital bombardment. Things to know: * set in the early 2100s * both worlds are inhabited by humans * both have advanced technology * Earth has about 11 billion people and Mars has 10-15 million I have came up with a few ideas but I need to know if they seem realistic or if there is a better way. The ideas are * nukes * antimatter * redirecting asteroids Are these viable ways for a space invasion, or is there a better way? [Answer] Check out Heinlein's "The Moon Is a Harsh Mistress", that deals with this problem from a lunar perspective. Bombardment from Mars to Earth (or vice versa) has some unique requirements: * Sophisticated navigation systems: at interplanetary distances, even hitting the plane require precise targeting, much less hitting specific cities on a planet * Some sort of AI controller: assuming the opposing planet is mounting a defense, they will likely have weeks to detect and prepare for incoming bombardments, and transmission delays can be minutes long, making planet-side control unfeasible. That leaves three likely approaches: 1. Slow, heavy, 'dumb' missiles: basically large asteroids with attached engines, and a comparatively simple guidance system — meant to be juggernauts. They plow through defenses by being too massive to deflect easily and cause inertial impact damage like a typical meteorite. 2. Agile 'smart' missiles: Missiles that are AI guided, and using some type of warhead. they try to actively evade defenses and deliver their payload to selected targets 3. Small, extremely fast, 'dumb' missiles: This would imply accelerating a smallish asteroid to a significant fraction of the speed of light, perhaps by an immense orbiting linear accelerator. The small size and high rate of speed would make detection and interception difficult, and reduce some of the complexities of targeting (since you could fire it almost linearly). This approach would probably produce and air-bust like the [1908 Tunguska event](https://en.wikipedia.org/wiki/Tunguska_event). Nuclear devices are reasonable; antimatter devices are somewhat out of reach for 21st century technology (we still don't know how to produce or contain antimatter in large quantities). I'm not sure why you're limiting the conflict to bombardment, though, when something like an Xray or gamma-ray laser (assuming the latter could be designed) might be more effective. A laser like that wouldn't disperse or attenuate much traveling through the vacuum, and could do some real damage (particularly on Mars, which lacks Earth's protective atmosphere). [Answer] For pure and simple orbital bombardment, you want to cram the target with objects falling from the sky. Any rock big enough to survive the atmospheric impact will suffice, and will spare the attacking side from excessive investments. If you are going to use nukes or antimatter, the vast part of the damage will be delivered by the explosion. In that case you actually want to be sure that the atmospheric reentry doesn't damage the device, complicating your design. [Answer] Tungsten rods are the typical munition of choice in a "Rods from God" scenario. Take a 10m Tungsten rod of diameter 1m. It would have a volume of 10m^3. A mass of about: 200000kg Consequently, falling from a low earth orbit of 1000km, it would gain: A kinetic energy of: 200000 \* 9.81 \* 1000000 = 2TJ. Further to this, an impact of this magnitude would cause a huge nuclear reaction at the impact site releasing yet more energy. The kinetic energy of this scales proportionally to the mass of the rod and the altitude it is launched from. Tungsten is usually chosen because it has a melting point of 3,422 °C so a rod made of it would likely survive re-entry intact. --- As an added aside, another benefit of using rods over meteroids is that the concentrated impact point will result in it being able to penetrate a target very deep in the ground, underground bunkers would not be safe. --- Since the comments have exploded in a debate around the practicality of "dropping" something from orbit, the other option would be to slingshot it around the moon in such a way that the return path was a direct collision with your target. This would require about the same amount of energy as dropping it from orbit (it takes about whilst also raising your effective altitude to 400,000km. This would give you an 800TJ impact from the aditional altitude alone. You could also manufacture the rods in lunar orbit to further reduce the energy costs. [Answer] While it seems that the kind of attack the nations of both planets would use are the same, i would argue that it is way more asymetrical. ## In General Every possible attack is more or less a balisitic object and have to follow newtonian physics. Asteroids and Nuclear rockets (anti-matter seems still way of to be realistic in 2100) will travel around 8 months before hitting their target. Enough time for counter measures if detected. In this regard, asteroids are exceptional good. They are dark, extremly cold and dumb. But hey are also untargeted and its impossible to hit something precisly. And depending on the mass hard to destroy, even if detected early. Rockets can have pinpoint accuracy, destruction comparable to asteroid impacts, but will need power and heat to work, so detectable by their emissioned heat. Also, EMP or simply shooting at it may destroy it. ## Mars Earths population density is way higher than mars. That means Mars could hit anything and would have a catastrophic effect on infrastucture and morale of the population. Additionally, Mars is closer to the asteroid belt that has some asteroids to throw at earth. That would make asteroids a great weapon to use by mars, as even a big asteroid hitting empty land or even the ocean can have devastating effects. Biggest problem is the size and mass to move those objects on a trajectory hitting earth. Still seems like the best weapon ## Earth I assume that the terraforming of Mars has not been done yet, so people on mars will life in sheltered groups, maybe below the mars surface with only a few buildings and accesses on the surface. Every attack has to hit its target or is wasted. But every hit will also likely have more devastating effects. One domed city hit could mean 3 Million lives, with no chance of survival. Additionally, while moving an asteroid on the mars trajectory would need less fuel, reaching it would take longer than those estimated 8 months for an direct attack with rockets. Also impacts on the uninhabitated parts of Mars would have less of an effect, as the atmosphere is thinner and so does reduce the effect of greater explosions. So earth would definitly would use something more precise like rockets. [Answer] **Phobos** The Earthlings slingshot rocks around the sun and Jupiter. They are not aiming for Mars. They are aiming for Phobos, the Martian moon and a rock bigger than anything practicably shot from Earth. If Phobos' orbit is slowed, it will crash into the Martian surface. Once it starts coming down there will not be much the Martians can do about it except evacuate the premises. <https://www.space.com/20346-phobos-moon.html> > > Doomed > > > But Phobos won't zip around Mars forever. The doomed moon is spiraling > inward at a rate of 1.8 centimeters (seven-tenths of an inch) per > year, or 1.8 meters (about 6 feet) each century. Within 50 million > years, the moon will either collide with its parent planet or be torn > into rubble and scattered as a ring around Mars. > > > [Answer] They could use any & all of those things, apart from getting the stuff out of their own gravity well pretty much all the same factors apply as in answers to questions about [how would the moon do it](https://worldbuilding.stackexchange.com/a/108429/49261). For both mars & earth staging their attacks from their respective moons is going to be easier. Raw asteroids need to be big enough to have a worthwhile payload left over after reentry. [Kinetic bombardment](https://en.wikipedia.org/wiki/Kinetic_bombardment) with shaped metal (or perhaps rock) with a ceramic heat shield skin could be smaller & also relatively cheap depending on the materials used. Its thinner atmosphere makes burnup considerations less of a concern for earth's attacks on mars. You may find something useful in answers to this [space exploration SE question](https://space.stackexchange.com/questions/26490/what-size-payloads-could-we-feasibly-launch-from-the-moon-with-a-mass-driver) with regards to launches from the moon. [Answer] Antimatter does not work, it will react with the atmosphere on the way down. For psychological impact, Martians could use Earth forces for orbital bombardment. Specifically, POWs and captured ships. The actual damage would be relatively small, but the demoralizing effect might be great. Earth forces could do the same, but the outrage caused in such a small population might outweigh the demoralizing effect and the forces used as the bombardment might become instant martyrs. [Answer] **RODS**! You would need to place in orbit around the planet a satellite with a targeting system. It would be filled with dumb metal rods. The sheer kinetic energy created from just releasing the rods in low gravity would obliterate any target. I see this as a useful solution if the point of the war is to keep the planet for resources. If you nuke it, then you limit the resources you can get. [Answer] ## Mars Can Use Planetary Mirrors to Create "Death Rays" Mars could deploy mirrors on it's surface to gather radiant energy from the Sun then beam it back at the Earth. The principle is the same as found in research telescopes, satellite transmissions, and radar. [![enter image description here](https://i.stack.imgur.com/XO0Ln.jpg)](https://i.stack.imgur.com/XO0Ln.jpg) Each mirror would be a few thousand kilometers in size and made of an array of smaller mirrors. The place where the red "x" is would be where the energy is collected. To vary the strength of the beam, the number of array mirrors "turned on" could be adjusted. A couple of really strong mirrors or prisms at the "x" would redirect the energy back out toward the Earth. It could only be "fired" when the mirror was in Martian daylight, thus they would install several at different locations on the planet so they could fire more frequently. It could also be strategic to have multiple firing locations. The Earth wouldn't know which from location on Mars would be firing. Also, it takes light a little more than three minutes to travel between Earth and Mars, so there would not be a lot of warning. This tech would heavily favor Mars. A beam from Mars would be much more powerful than one from Earth for two reasons: 1. Mars does not have an atmosphere to block collection of solar energy 2. Mars wouldn't have many surface buildings or features to hamper construction of really large mirror arrays The amount of solar energy collected would be massive. So massive, that they may only be able to fire each mirror array a couple of times a day because of the danger of overheating. ]
[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/37603/edit). Closed 7 years ago. [Improve this question](/posts/37603/edit) As we know, light has no mass. Well light having mass is the primary problem with fast(er) than light travel. Thinking about this classic, yet sad problem made me wonder, what would happen the the world if light photons suddenly had equal mass of 1/100 of Hydrogen atoms? [Answer] ### Note that introducing a mass for the photons would have fundamental implications on the electromagnetic force and thus large consequences on many parts of the physics as we know it. But that has been treated by other answers or in the comments below. --- But if, out of curiosity, we handwave that away, we can see that there would be a lot of implications of this that you have to take care of otherwise, as @bowlturner suggested, the result is massive destruction. For example: # Doomsday 1 [According to someone on Reddit's calculations](https://www.reddit.com/r/askscience/comments/2n6zo0/how_many_photons_per_second_would_hit_a_1_cm/) as a rough estimate, $10^{17}$ photons hit a square centimeter in full sunlight each second. That converts to $10^{21}$ photons per square meter. Now consider your heavy photons. Using the non-relativistic calculation for kinetic energy (note that the relativistic calculation would be even greater), we get $K=0.5mv^2=0.5mc^2\approx 7.5\times 10^{-13}~\rm J$ per photon. That means each square meter will be receiving about $7.5\times 10^8~\rm J$ per second. Compare that to the $6.3\times 10^{13}~\rm J$ of [the nuclear bomb that was dropped on Hiroshima](https://en.wikipedia.org/wiki/Little_Boy). We're getting that much energy per $10^5$ square meters of area, or the area of circle with a 178 meter radius. The initial fireball produced by the nuclear bomb was 370 meters in diameter. So the energy delivered is comparable to that of being near ground zero of a nuclear explosion. Keep in mind, that's the energy delivered *per second* by your heavy photons. In other words, the Earth is going to be obliterated. Absolutely and completely. # Doomsday 2 Another issue with the first scenario is that it violates conservation of mass and energy - a lot of it suddenly comes out of nowhere. Let's try slowing them down enough that their kinetic energy is equal to the energy they had beforehand. Using a photon somewhere in the visible spectrum, $0.5mv^2=K=E\approx 2~\rm{eV}=3.2\times 10^{-19}J$. Solving for velocity with the heavier mass, we get $v=138~\mathrm{km/s}\;.$ That doesn't sound so bad. ...until you notice that that's less than [escape velocity from the sun's surface (617km/s)](https://en.wikipedia.org/wiki/Escape_velocity#List_of_escape_velocities). Also, from the Earth you only need to go 42km/s to escape the Sun's gravity well, so going 138km/s isn't going to be enough to get a photon from the Sun to the Earth. So photons can't reach the Earth, the Earth goes dark and freezes, and everybody dies. Whoops. # Doomsday 3 Okay, so what happens if instead of reducing their speed we reduce how many there are? Using my previous estimate numbers, $3.2\times 10^{-19}~\rm J$ per photon compared to $7.5\times 10^{-13}~\rm J$ per heavy photon means a reduction to about one one-millionth of current levels. Of course, that's *way* higher than the [bond dissociation energy](https://en.wikipedia.org/wiki/Bond-dissociation_energy) of any known type of bond. So rather than being absorbed and providing heat, these photons are going to be blowing chemicals bond apart. So the photons are still deadly. # Doomsday 4 In each of the above scenarios, I've intentionally ignored quantum mechanics. What happens if we take quantum mechanics into account? Well, photons are electromagnetic waves, so that means the electromagnetic force is affected. That affects how electrons are bound to an atom, and how atoms would bind together to form compounds. So if you aren't going to handwave away quantum mechanics, all molecules are going to just kinda fall apart. --- Note that in each of these scenarios I'm only focusing on a single aspect of why things would go horribly wrong. There are going to be additional things causing havoc that I haven't mentioned, such as in the first scenario the ramifications of conservation of mass and energy no longer being true. [Answer] Very not good. In quantum field theory, interactions are mediated by force carriers. The range of these force carriers depends on their mass. Photons are the force carriers for electromagnetism. Being massless is why EM has an infinite range. Mass would change that. All of electromagnetism would be range limited, and to fairly microscopic distances. The earth's magnetic field would vanish, and magnets would stop working, because they can no longer affect things at a distance. The only things that could produce light would make light with wavelengths in the gamma spectrum of energies. Normal light wouldn't happen. Photons wouldn't travel at c - in fact, it doesn't solve the speed limit problem. [Answer] What's the difference between electromagnetism and the "weak" force? Mass! Massive bosons would mean that the electic force would have a short range. This would mess up the existance of atoms. [Answer] Not good. The Sun emits approximately $4.2 \cdot 10^{44}$ photons/s, and with your stated mass, that would be $7 \cdot 10^{15}$ kg/s. That means it would have radiated away all its mass in just $3.3$ billion years, slightly disappointing for us living $4.5$ billion years after it was formed. So, for something a bit more destructive, a mass moving at the speed of light (per definition) exerts an infinite force on things it hits. In short, everybody dies, and absolutely every part of the universe is torn apart. Solar cells may be slightly more efficient though. [Answer] Then the coulomb force would be $$F\_E=\frac{Qq}{4πε\_0r^2}e^{-\frac{mγr}{ħ}}(1+{\frac{mγr}{ħ}})$$ with $F\_E$ being the electric force, $Q$, and $q$ being the electric charges, being the $ħ$ being the reduced Planck constant, $ε\_0$ being the permittivity of free space, $r$ being the distance between the charges, $mγ$ being the mass of photons. This means that the force between two electric charges would decrease with distance exponentially instead of simply with the square of the distance. This also means that it would be possible to figure out that photons would have a mass of 1/100 the mass of a hydrogen atom based on how the force between two electric charges would decrease with distance. If light had a mass of 1/100 the mass of a hydrogen, then it would be possible to travel faster than photons as photons would travel at less than $c$, but it would not be possible to travel faster than $c$ as while $c$ is referred to as the speed of light it really does not depend on there being light, but instead depends on the Lorentz factor. So if you want a universe where it's possible to travel faster than photons, then having massive photons would allow this, but if you want a universe where there is no cosmic speed limit, you would need to make more changes than simply having massive photons. [Answer] Nothing would change from our perspective because all the information about what would have happened had the change not occurred would still be present in the universe due to unitary time evolution. So, even though the universe looks like having become completely different with short range electromagnetic interactions, atoms suddenly decaying as a result, etc. etc., you can transform to a different basis in Hilbert space by applying the inverse time evolution operator to the time before the change happened and then the time evolution operator using the wrong Hamiltonian that doesn't include the change of the mass of the photon. If you write down the quantum state of the universe in terms of this new basis, then the universe looks the same as what it would have been, had the photon stayed massless. In particular we would still exist, observing the same universe that from our perspective hasn't changed at all. ]
[Question] [ In the past I've entertained the notion of space stations and spaceships having window panes or transparent viewing surfaces made from laboratory-created diamonds, but a recent answer to a different question on this site has led me to question how effective (or *not*) this would be even if it were possible- assuming it is even possible to create diamonds with the appropriate dimensions for a viewport on such a structure- would they serve as safe and effective for the task? [Answer] Diamond is very hard, but unfortunately [it is also a bit brittle](https://youtu.be/eNYiKRJwUBU?t=29). If an object with enough kinetic energy hits it, the window can shatter completely. This is not an acceptable risk in space. Suitable window material should not shatter even if it breaks. Eg. [car windshields had this problem](https://en.wikipedia.org/wiki/Windshield#Safety), and that is why they are today made of [laminated glass](https://en.wikipedia.org/wiki/Laminated_glass) to mitigate this risk. If the glass is hit, the glass cracks, but typically [the windshield still stays as one piece](https://cdn.abcotvs.com/dip/images/12899694_030123-wls-windshield-ice-6a-vosot-vid.jpg?w=1600). Maybe it is possible to do something similar with your spacecraft windows, ie. use diamond instead of glass and laminate it to prevent shattering. [Answer] Diamond is good for some things like cutting, but not for things like resisting impacts. It is very hard, and consequently very brittle. Laminating might counteract that weakness, but I doubt it would make much sense in terms of weight and budget. We're already in the future anyways. [Transparent ceramics](https://en.wikipedia.org/wiki/Transparent_ceramics#Armor) are a thing already, and it will only get better and cheaper. ISS' Cupola module uses "[fused silica and borosilicate glass panes](https://www.nasa.gov/centers/kennedy/stationpayloads/cupola.html)" for its 7 windows, and shutters to protect them when not in use. It's been working fine for the last 13 years, they even managed to replace panes. We've also created things like aluminium oxynitride which can make for much light bulletproof panes, or sapphire which is already used in iPhone lenses. The military is very interested in those things, because lightweight and transparent materials have a lot of interesting applications, so it's safe to bet we'll be able to make transparent viewports that aren't total structural weaknesses by the time we're able to make cool spaceships. But it won't be diamond. Diamond just isn't the right material for armor. If you really want diamond, I can see two options. You could imagine a carbon-based material, like a transparent carbon ceramic nanotube matrix thingamajig, and call it "diamond window" because diamonds are carbon and marketing will probably still exist in the future. Or you could have a diamond pane under a proper transparent ceramic pane, and that's technically a diamond window (with non-diamond transparent armor). [Answer] Diamonds isn't particularly resistant to impact, with a fracture toughness of 2 MPam1/2. If you want a resistant and transparent material, you could instead use Yttria-stabilized cubic zirconia (bonus for the cool name), with about 3.7 MPam1/2, or sapphire with 4.2 MPam1/2. If the goal is to have highly impact resistant material, going for a composite structure is probably much better. Stacking layers of transparent materials in a similar way an armor is built could make for a very strong material. Laminated sapphire with graphene could be extremely resistant. Adding a shock absorbing material like polycarbonate can greatly improve impact resistance while staying transparent. [![enter image description here](https://i.stack.imgur.com/oan5U.png)](https://i.stack.imgur.com/oan5U.png) [Answer] "Windows are structural weaknesses. Geth do not use them." - Legion, Mass effect 2 Why would you need windows anyway? If you want to look outside you can have a sensor outside and a screen inside. Same results with none of the engineering issues. And if you are afraid that an insane A.I., khm, your friendly computer will try to manipulate the view you can make it a closed system and not connect it to the network. Because windows made of any material WILL be a weakness in the structure. And if you somehow create a transparent material better than what the hull is made of, then why not create the whole thing from that transparent material? [Answer] Synthetic diamond can be used as an armor material. It's no different from AlON, sapphire, or just plain glass in that regard. All armor ceramics are brittle, by their very nature. Diamond isn't particularly more brittle than the rest. However, it's notoriously difficult to fabricate, the only means to make flat diamonds is through chemical or physical vapor deposition, which is hard to do in a thick layer. You also still need to layer it with tougher polymer layers. There's no massive advantage to using diamond over sapphire or AlON. But diamond-like coatings are used widely where a very hard surface is required. [This includes optics](https://www.edmundoptics.eu/knowledge-center/application-notes/optics/diamond-like-carbon-coatings/). The primary advantage of ceramics in armor is their hardness, allowing them to blunt incoming metal projectiles. In space, you are more likely to face hypervelocity projectiles, against which hardness doesn't help much. Brittleness, however, isn't such a big problem either. A window with its outermost layer made out of diamond will likely retain its transparency longer, better resisting the effects of space dust than other ceramics. In all other respects, it won't be very different from AlON or glass. If you're in a high sci-fi setting, and don't want to use the same aluminum oxynitride as everyone else probably does, there's nothing very wrong with diamond. ]
[Question] [ **Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/200153/edit). Closed 2 years ago. [Improve this question](/posts/200153/edit) There are 2 kinds of portal scrolls which are equally reliable and can handle similar traffic regardless of distance, the consumable or one time use only and the reusable or can be used more than 2 times very handy and economic. So once the consumable portal is closed all of it's history is erased along with the scroll, as for the reusable the history will be rewritten or overlap instead! Normally both types of portal scrolls have their pros and cons but I wonder why the military would ban the use of reusable scroll only? [Answer] As a military one of the least things you want is that the weapons you carry will be reused by the enemy you are attacking. That's why very often weapons and supplies are destroyed before surrendering or defeat. Now it's easy to imagine that letting an enemy have easy access to a portal with which they can easily go around your defenses is definitely a no no for any military planner. Plus there is also the need to ensure that the supplied ones are used for what they are meant, and not for less martial purposes, like visiting the brothel in the nearby city and getting back unnoticed while supposedly being on guard duty. So, single use portal scrolls and a very severe release policy will ensure that no misuse is done. [Answer] Security and secrecy are great answers... but I thought also of pilots being bolted into kamikaze aircraft and manned torpedos in WWII... to help them remember their honor. To a much less permanent degree, when I was enlisted I experienced hundreds of little military rules about where you are and what you are doing... all of them designed to prevent you from straying off a very specific path. It would be nice if our fighting boys didn't hop to the theater of war, then immediately bounce to Aruba, then back after the fighting was over to be there when the generals show up. [Answer] ## Secrecy and security: Armies could have a number of motives for this. The biggest I can think of is secrecy. * **Secrecy:** A huge part of military activity is making sure the enemy doesn't know what you have done, are doing, and plan to do. If a scroll is on the battlefield, some of them will be captured. So if you have a supply depot full of valuables, your enemy can use the reusable scroll to locate and send troops to attack it. You can find out where and when these troops have deployed and re-deployed. If you figure out the enemy commander teleports to the same location once a week (and it's corroborated that other commanders do so as well) then you've just located where and when they have their planning sessions and kill all their senior leadership in one fell swoop. With a one-shot scroll, no problem. Your mage using the scroll still has to know when and where the secret meetings are held, but a suicide pill or a memory-wipe spell can take care of that. A reusable scroll is physical proof, and a captured mage could be lying to you, or mis-remembering, or a plant to feed you false info. * **Independence and trust**: Military organizations also often believe that their units and commanders should be capable of functioning independently. Perhaps your army wants officers to make due with what they have as much as possible. This approach could vary from army to army. An army with a strong central command that doesn't trust their officers to be competent or trustworthy (think the Red army in WW2) would want commanders to be dependent on the central supply, only getting a new scroll every time they use one, so they don't get independent ideas and go off on their own/rebel. An army that encourages maximum independence would want the concern over wasting single-use items to restrict the desire to be a weak commander and be constantly checking in/topping off (possibly limited) supplies. * **Cost**: Perhaps the one-use scrolls are cheap. The supply chain folks want units to be able to resupply magically, but reusable scrolls are expensive. Rather than train your troops so they are used to easy supply refills, you give them dirt-cheap scrolls and let them know they can get another one when they use the last one. When you're fighting, the eventual cost of using disposable scrolls adds up, but in peace time, you don't have to invest in expensive reusable equipment that you don't use until a war breaks out. [Answer] **Reusable scrolls are more expensive:** There's no good way to modify one after creating it. A normal person might get a reusable scroll pair to go between their home and work, and get a new scroll when they change jobs or houses. The military doesn't have a "commute". Scrolls are for emergency evacuation in battle, or moving troops around in mass. There's very little back-and-forth movement, and even if a reusable scroll isn't that much more expensive, there's very little point in creating one for a one-time move. They may have a few reusable scrolls around for moving between common destinations, but they're still going to be ordering single-use scrolls by the truckload. **Reusable scrolls have a shorter range:** Teleportation cost increases with distance. While it's possible to create a reusable scroll that can teleport you to the next city, it's really expensive, and past that it gets even worse. Single-use scrolls, on the other hand, don't bother to absorb the magical backlash without damage. That gives them much better range, at the cost of literally disintegrating upon use. **Reusable scrolls need skill and time to use:** A single-use scroll is simple; just break the seal, and the spell inside will auto-cast. A reusable scroll requires someone to read it, make the appropriate actions, and focus properly. It's not that difficult, and most people can learn how, but doing so while being shot at is an issue. Using a reusable scroll after being shot is even worse. [Answer] Efficient armed forces run their logistics and acquisitions basing themselves on cost-benefit analysis. If they have a preference for the one time usage scroll, it's because it is cheaper to mass produce and/or distribute to troops, or for security reasons as mentioned in [Dutch's answer](https://worldbuilding.stackexchange.com/a/200156/21222). The multiuse scroll might be called "economic" but it might be the kind of economy that only the filthy rich can use. Also even if they are indeed economic, if a squad is not supposed to be teleporting much during battles than the cheaper, one use one would be preferred. [Answer] Depending on the mechanics of teleportation there can be several reasons for this: 1. reusable scrolls require user input of coordinates If your reusable scrolls require user input, all military personnel has to go through special teleportation training: Memorise coordinates; learn to calculate coordinates; learn to input them; etc. This can be costly, time-consuming, and dangerous since your enemies can find out the coordinates of your bases by interrogating your soldiers. Single-use scrolls with fixed coordinates do not require any training apart from scroll activation. They can be used easily by any level of military personnel. As an added bonus, soldiers cannot use these scrolls for unregulated unsupervised activities. 2. reusable scrolls require special resources to activate Teleportation cannot be cheap, otherwise, there is no need for the military -- a group of elite assassins will suffice. Single-use scrolls can be already imbued with the power necessary for teleportation and do not need any special resources to activate. Reusable scrolls need to be recharged/require a mage/whatever, therefore their use is limited to people and situations where necessary resources are at hand. It may be possible to have 'charged' reusable scrolls, but it can be potentially dangerous due to the human factor -- someone forgot to charge scrolls and the entire division is wiped out. Single-use scrolls are much more reliable in this sense. 3. single-use scrolls create less stable portals (or whatever your magic system calls for) and make it harder for enemies to trace movements Single-use scrolls create fewer (or more, it does not matter as long as the final result is the same) spatial disturbances as reusable scrolls, so it is harder to trace movements. If your enemy cannot trace your movements your chances of successful ambush or escape are much higher. It also makes it easier to hide HQ and resupply bases. 4. reusable scrolls can teleport only to a specific set of coordinates Again, it depends on the mechanics of teleportation. You can make your reusable scrolls as 'keys' opening already existing spatial corridors that lead to specific destinations. It is surely handy for trade and civilian transportation (easier to control, regulate, and tax), but it is impractical for the military. Your single-use scrolls will be 'true' teleportation scrolls that create independent spatial corridors. --- These are just some examples of what can be done. You can come up with something more suitable for your particular setting if you look carefully at teleportation mechanics, scroll production, and methods of warfare. [Answer] **Stop the Enemy using our Portals.** Suppose we want to port from the front lines to the garrison and close the portal after us. To close the portal we simply activate the scroll a second time. The catch is that the scroll cannot be put through its own portal without catastrophic consequences (potential plot point). That means someone must stay on the front lines to close the portal. This is a problem in a *total retreat* scenario where we want everyone back to the garrison as soon as possible. It means we have to either (a) leave someone behind or (b) leave the portal open. This means our enemy could use the portal to invade our garrison from inside. Especially bad if the garrison location is secret. **Other Ideas:** **Benefits/Drawbacks:** Perhaps reusable scrolls are created with the anchor points already written into the spell; but single use scrolls have the anchor points decided just before casting. It's a marvel of runic technology that the spell can be *suspended* like this, and altogether too much to hope for a reusable version of the same. **Catastrophic consequences:** The commanders of garrisons A and B refuse to hold reusable scrolls to travel between the two garrisons. The worry is that the enemy could sneak in, steal the scrolls and, by passing them through their own portals explode both garrisons at once. Kablammo! **Damage control:** A lost or captured reusable scroll is much worse than a lost/captured single-use scroll. I presume you are thinking about a story where the protagonists need to teleport some number of times, and then stop teleporting at risk of trivializing the plot. Well guess what, preventing this kind of hero shananigans is exactly the reason their enemies (and everyone else) only use single-use scrolls in the first place! [Answer] A **tradition of boat- and bridge-burning.** There are [a variety of ancient accounts](https://history.stackexchange.com/questions/14512/which-military-commanders-burned-their-own-ships) (and even a [quote from the art of war](http://changingminds.org/disciplines/warfare/art_war/sun_tzu_11-8.htm)) of military commanders burning their own boats, or the bridges behind them. The (rather Machiavellian) idea is your troops will fight harder when they know retreat isn't an option; and the proof of your determination will inspire fear in your enemies. Perhaps this was done in your society's most famous battles, and is maintained to this day *partly* for functional reasons but *also* for tradition - just like armies maintain swords and silly hats. ]
[Question] [ In my fantasy world, revenants are a special type of undead. They only occur when a person dies feeling that they were wronged in life. If their soul contains enough hatred for those who wronged them, they will come screaming back into the mortal realm, and force their dessicated corpse to move through sheer force of will. The revenants are stronger, faster, and smarter than they ever were in life, not to mention vampiric, and are incapable of death. It doesn't matter whether they are cut apart, blown up, or their bones are broken, they'll just pull their bodies back together and keep on going. They only return to the afterlife when they find the person(s) that wronged them in life, upon which the revenant will murder them as brutally and painfully as possible, as penance for their wrongdoing. They will not rest until they find them, and will not hesitate to kill anyone who gets in their way. If this is a relatively common occurance, there are obviously going to be some cultural ramifications. Burial practices will probably be effected in some way. Perhaps law and justice is altered, in an effort to prevent revenant occurances? Maybe people are just nicer to eachother. By the way, the culture in question is similar to 1800's america. How considerably would this culture be altered by revenants? [Answer] It sounds to me like one's best bet to deal with a revenant (assuming you're a target and don't wish to be) would be to contain it. Place the revenant in some situation that it cannot escape-- at least, not until the person who they want to kill is already long gone from natural causes. To that end, I'd imagine that you have people who would establish businesses where they would attempt to prevent the revenant from accomplishing its goal. As Starfish Prime stated in their answer, it might be a good idea to cast the revenant in concrete after blowing it apart, depending on how they work when blown up. They might lock a revenant in an iron vault of some sort (since iron is said to have powerful properties against the supernatural in some folk lore). The idea here is that the revenant might be able to wear through the metal through time and energy expended-- but it will almost certainly take decades to do so-- at which point, the revenant's target will have already passed. I think that it would make crime a little bit less personal, with a focus on anonymity. If I'm going to do something sinister (and there will always be people who do something sinister), I would want to disguise myself. If I can prevent you from knowing my identity, that's kinda useful (the revenant would only know who to look for if I re-used my disguise). But if I could convince you that I was someone else entirely while I did something sinister? Maybe even an enemy of mine? Why, I could kill two birds with one stone, potentially! Example scenario: Jane Q Evil is a vindictive and greedy lass. Her half-sister, Becky J Good stands to inherit the complete family fortune when their parents die, and Becky already has a family and children. Jane knows that her sister would leave all of the money to her husband and children, but never to Jane. Jane also passionately hates her stepmother, believing that her father made a mistake with that marriage. Jane disguises herself as Becky, then starts to do innocuously crappy things to her stepmother. Nothing too huge-- stepping on her dress without apologizing, stealing a few dollars from her, etc. When the stepmother tries to confront the real Becky, Becky obviously denies it and says that that didn't happen. The stepmother is now starting to really dislike Becky, as it seems that she's gaslighting her. This is the most dangerous part of the plan-- if Becky ever figures out that it's Jane disguised as her, Jane's got a potential revenant on her hands. But if Jane can convince Becky that their dear old step-mother is starting to go senile, she's got a great situation on her hands. Jane, disguised as Becky, murders her step-mother one night. She makes sure that the step mother gets to see that it was "Becky" who killed her, and that she knows that the murder was purely out of greed and the desire to swindle for money. In short, she ensures that her step-mother becomes a revenant. A few days later, the step-mother comes back and murders Becky. Jane's hands are clean in that murder, where she would most clearly stand to benefit. Now Jane can just wait for her father to pass and rake in the dough. Of course, if Becky's suspicious of something, she might order Dear Old Mom's corpse to be placed in a cast iron safe filled with concrete and buried in quicksand that her mother couldn't crawl out of as a revenant. That would put quite the hitch in Jane's plan! Edit: Your post asks for culture, and while crime is an aspect of culture, I'm definitely not answering your question completely. I think that different groups might view revenants differently. Ordinarily, assuming all is well, it might be super common to put all corpses into a standard burial practice where a revenant couldn't easily escape (IE the iron coffin caste in concrete). But what about a case where there's an unsolved murder? The town might take a vote to leave the corpse free so that it might solve the murder and kill a murderer in their midst. One other thing I think you'd find-- there wouldn't be such a thing as slavery in this world. 1800's America thrived on the cheap labor of indentured servants (who were hit with wildly unfair labor contracts) and the free (minus food and housing costs) labor of slaves. Both groups would be extremely inclined to come back and kill the people who used them for their entire lives. Workers probably have really, really good compensation in this world; a mogul can't afford to demand 15 hours days 7 days a week from people who might come back and murder him in a few year's time. There's probably a strong inclination to respect the elderly, and a ton of disrespect from the elderly toward those younger than them. Consider-- if grampa dies hating me, he probably comes back and kills me while I'm still relatively young (in my 20s or 30s). But if I'm grampa and I'm a completely terrible human being to my grandchild-- I'm dead by the time that kid passes! What do I care if the kid was upset enough with me to become a revenant? Doctors may be extremely scarce in this world (and those who are around are highly revered). Medical practices might also not have advanced beyond what seems obvious right now. If a doctor does something that people view as controversial (say, creates an early vaccine with scrapings from a scab that comes from an infectious disease) and a patient dies (whether because of what the doctor did or not), there's a decent chance that the patient or their relatives/dependents will interpret this as being the doctor's fault. If someone believes that the doctor is responsible for their passing and they left a dependent family behind, they might come back as a revenant and kill the doctor. [Answer] **Say goodbye to government** If these things can't be killed by any means, say goodbye to any form of organized of government, ever. You can't be in charge of a large government without making people hate you with a passion, so that means anyone with power can last about a few weeks before some revenant goes after the poor sap. (And if you doubt the truth of this statement, take a look at outside.) The time scale for death, of course, is adjusted based on level of general despotism, a genocidal dictator will probably last hours whereas a pure-hearted democratically elected leader by 90% of the population might make it two months. Basically, everything's going to be settlement based in small groups of people with the inhabitants trying desperately not to irritate their fellow man. It'd be like mutually assured destruction, except with being nice to people, and thus any large form of organization, which by definition will screw over the little guy in the giant gears of the machine, will fall apart. This is not a good thing as civilization will kind of just stall because that's only natural when any crank who dies will just rise from the grave and take out his enemies. I mean, there won't be large scale war either, (assassins, yes, but anyone worth assassinating probably has a few revenants after them) but imagine a world where no one wants to talk with anyone they don't already know for fear of offending them. [Answer] > > force their dessicated corpse to move through sheer force of will. > > > What if they were cremated? What if they were eaten by predators or scavengers, and their component molecules are now various distributed around a bunch of animals, plants, and some slightly-more-fertile-than-its-surroundings patch of soil? Will there be poop-revenants? > > They only return to the afterlife when they find the person(s) that wronged them in life > > > If I dump your body in a foreign country where you don't know where you are and don't speak the language, you're gonna have a real problem tracking me down. Exchange of corpses might be a sensible thing for neighbours to do, like the old "*bury them at a crossroads so their ghost won't know which way to go*" idea but a bit more thorough. > > It doesn't matter whether they are cut apart, blown up, or their bones are broken, they'll just pull their bodies back together and keep on going. > > > Blow em up, set the bits in concrete. Separate the bits. Maybe throw some of them in the sea. It'll take longer than the lifetime of the target for them to get themselves back together, if done sensibly. > > If this is a relatively common occurance, there are obviously going to be some cultural ramifications > > > Not following proper safe burial practises might become a crime. Mere suicides will probably be largely replaced with murder-suicides, probably with the murder after the fact. Might be safest just to kill anyone with signs of mental illness ahead of time, so you can guarantee they'd be buried properly. Warfare is going to become somewhat more unpopular, because everything is pretty much mutually assured destruction. Any work that requires you to travel far from home where you might not get the right sort of funeral rites might end up like a sorts of "untouchable" caste. Never let a sailor see your face, lest he drown on his next sailing and blame you, sort of thing. There are probably many vaguely related things like merchants or exiles or hermits or nomads or indeed people just living on their own, if they're not checked up on regularly, might be treated with similar fear and suspicion. > > Maybe people are just nicer to eachother. > > > Haha, no. Be realistic now. Revenants rising from the earth and wreaking vengeance on those what done them wrong is *way* more plausible than people becoming basically nice human beings. [Answer] # A world overrun by the dead Your rules provide for a number of ways to create a revenant that will effectively never rest. More of them will be created all the time. An ever-increasing tide of revenants slowly but inexorably chokes the life out of Mankind. You should probably close these loopholes. ### Loophole: a revenant can't kill a dead person If I am parsing your rules correctly, if even a single person on a particular revenant's hit list dies, but not by the revenant's hand personally, that revenant will never go away. It will simply keep on killing ... forever? You might be able to convince the revenant 'no, really, they're dead'. Or you might not. Many people have died whose bodies were never found, especially if they happened to die in a secluded area. ### Loophole: Two revenants want to kill each other Perspective being malleable as it is, it's easy to imagine scenarios where two people hate each other, each believing the other one screwed them, and they can die close enough to each other to become revenants. ### Loophole: The revenant hates everybody This could happen in numerous ways. Take a notorious psychopathic killer who doesn't give a crap about anyone but himself. Literally, that's what a criminal psychopath is: no conscience whatsoever, an inflated view of self-worth, a huge hypocrite, cares only about themselves. So when you execute one of them, they might well feel like the entire world has done them an injustice. Or someone who is upset and disturbed enough to go on a mass shooting could become a revenant. They felt wronged by the world enough to lash out *in life*, after all. ### Loophole: Revenants with vendettas against entire groups Terrorist revenants, soldiers killed in battle become revenants obsessed with killing 'the enemy', particularly virulently anti-semitic or white supremacist race-war true believers who die of natural causes, there are lots of ways this can happen. [Answer] It would depend on how long this revenant phenomenon has been around. If it has been that way since prehistoric times, humanity and civilization would have evolved quite differently. Ancient cultures started as hunter-gatherer societies and were much more community-focused. There would be strong cultural practices surrounding 1. Making sure everyone knows how it works, at least as well as is understood. No doubt it would become an important part of early proto-religions. 2. Dispute resolution. Some form of community support and a relatively universal understanding of justice. It could be violent, like [blood money](https://en.wikipedia.org/wiki/Blood_money_(restitution)), although early cultures didn't have money per se so something else would have to be worked out. I would prefer more non-violent solutions. Community therapists of some sort: many early cultures had wise men, shamans, matchmakers, and various other important social roles. There would be someone whose role is to settle disputes and ensure fidelity and harmony. People would mostly be willing to take part because everyone understands the consequences of not doing so, and it is something that they strongly believe in due to their religion. And in this case, it's based on actual real consequences, not just faith (although depending on how successful they are, it would still happen perhaps once every average lifetime of an individual since the younger generation has never seen it before). 3. Forgiveness is an important part of the culture and religion, managing one's emotions is taught from a young age, like in many Buddhist societies. Meditation, controlled breathing, the taming of the passions, self-control. Like the Jedis, if you like. I'm basically envisioning Native American society + Buddhism. Warfare would consequently be very uncommon, people would literally be forced to negotiate and practice diplomacy. Society would likely develop either more slowly or much more quickly, it's a bit up to your imagination. In a larger society, it is harder to maintain social cohesion, but maybe their peacemaking skills would actually lead to a more utopic type of society. There would still be risk to manage, but the religious aspect likely would be more dominant. Consider this: people wouldn't fight over whose religion is correct because everyone comes back from the dead no matter which religion they believe. Therefore I would assume there is not a lot of structure to the religion (such as in Buddhism) as to specific interpretations, perhaps it is more Deistic, this allows it to be more universal. I still predict a lower density of the population. Note that people will pretty much be guaranteed to believe in a spirit of some sort, and life after death (perhaps reincarnation?). From this perspective, if it's something that has always been this way, then start with how you think society would have organized in early times and try to imagine how it would evolve forward. If you want organized large scale agrarian/industrial societies to exist, then think about how society managed to get that way without people getting killed. This assumes that the risk of the revenants can't be managed by some means, such as cremation or prevention in some way as others have suggested. This then largely depends on the details of how you want it to work. If it's unavoidable for the most part, then society would be forced to evolve harmoniously or else remain as relatively small communities. If it's able to be managed and avoided, then perhaps people develop more selfish tendencies over time as the risk becomes lower. Even so, the mere fact that people literally come back from the dead due to their willpower is pretty incredible and will have a huge influence on people's understanding of the universe and metaphysics, and it will play a central role in any religion. [Answer] Since this question is about cultural changes, let's assume that the long term effects are minimal. People quickly figure out not to piss anybody off too strongly. Since most people don't anyway (I expect even 200 years ago, most people didn't die with hugely strong grievances), the only people truly affected are the famous and the powerful. If you're famous enough to have a stalker, you can basically be sure that you'll have to deal with a few revenant experiences. In the America of the 19th century, I imagine it would be a catalyst for the already strong religious sentiment. The population could easily be convinced that the revenants are a sign from God to punish the wicked and to keep the population honest. Halfthawed's anwers hints at the difficulty of wielding any power without wronging people enough turn them into revenants. The people who do wield power, can point to this as a sign of their virtue. Their lack of revenants shows that God considers them a righteous and virtuous leader. The real trick, of course is not to never ever wrong anybody, but to make sure that other people do your dirty work. Make sure that low level military and law enforcement get the blame, find some disadvantaged part of the population and make sure that society blames them for whatever is wrong, but above all, keep your own hands clean in the eyes of the people. So, basically the same as it ever was, but a little bit more. Meanwhile, use the revenants to your advantage. If you have a dangerous opponent, just make somebody believe that they died because of the opponent. Spread enough lies and wait for some misguided sap to kick the bucket. It may be possible to keep a few revenants at bay forever if you're powerful enough, but then it just becomes a game of making sure that your opponent has more revenants on their back than you. In short **sycophancy, two-facedness, and manipulating the public using extreme religious sentiment would be the only way to survive in a political career, and the American culture would develop accordingly**. [Answer] One of the most obvious societal changes is going to be in burial customs. Since the Revenant is going to be dangerous to everyone who gets in its way, there is going to be societal pressure to make sure that they cannot pull themselves together quite so easily. The best way to do that will be to cremate all bodies and scatter the ashes to the wind from the nearest mountaintop, or to scatter in phases over rivers or in ocean currents. Whatever it takes to get all the bits as far away as possible from the other bits. Revenants, in most fiction I have read, dissipate after the death of their target. So if you can arrange things so that it takes decades for a revenant to get all of it's bits together. That way there is a very good chance that anyone who is a potential target for a vengeful monster will be dead before it even gets a chance to fully form. Depending on how fast someone goes from corpse to revenant is going to make solving crime different. The practice of extensive autopsies would go by the wayside in the rush to get the corpse into a crematorium as fast as possible. Would you want to be the ME when the thing might wake up at any time? Crimes of passion might go down, while pre-meditated murders that include remains disposal will go up. I dunno, humans aren't always that bright. You are really going to have to develop tight rules surrounding the creation of a revenant in the first place. Does one happen only as the result of certain circumstances, or is anyone who has a little bit of spite going to be a candidate at death. Also, how long does it take to become a revenant if a body is left alone? Hours, weeks, years? If it takes a week from time of death it's one thing, but if the time span is hours it will be very different. The last thing to give a lot of thought to is how the revenant determines who it's going to go after. Does the Revenant get absolute clarity on who did what, or can the spirit be effectively fooled, like in some of the other answers. This will be important because it will affect motivations. If someone knows that if they do someone dirty it's going to come back on them in a very absolute fashion, they may opt not to do the crime to begin with. I'm surprised I don't see revenants more often in fantasy literature. They can be so interesting. [Answer] I'd say that the answer relies on the likelihood of revenants? And, the closely related question, what's the least likely people can make it? If revenants are very common - let's say there's a fifty fifty chance of a corpse coming back - then society is in trouble. If there's a one in hundred chance, then that's more an inconvenience to society than anything. Presumably there's some threshold, so how high is that threshold? What sort of probability is civilisation dealing with? Say, if someone come back as a revenant to target the man who killed your spouse, then that's fine because spouse murders don't happen very often. That's barely a blip as far as civilization is concerned - noticeable, but everything else is the same. But say, if you could come back as a revenant to target a sheriff who gave you a ticket, or a stolen toy, or a coworker who chews with his mouth open... that's much more of a problem because they are very common. Sure, people could lock every corpse up in a steel box and bury them in the ocean... but if you have to do that then civilisation will never form in the first place. If there's that much risk with every body, then the monkeys would never be able to leave the trees in the first place. (Say what about animals? Can any animal come back as well - because if they do then being a butcher will become a very a dangerous profession) The simple way to stop them is to make them less likely to happen. Here's some ways I think society will change... Governments will avoid culpability. If there's the risk of summoning an immortal being as consequences, then its easiest to avoid giving them a target. Expect any real leadership to remain faceless, or appoint replaceable figureheads that are easily sacrificed while the real power system remains shrouded and anonymous (I know, totally different from real life...) Sheriffs, judges and hangmen will wear masks, to keep their identities hidden against any vengeful spirits of outlaws they sentence. Armed sheriffs travel to neighboring towns to work, so nobody in their precincts knows who they are or where they live. If ever a revenant comes after, they simply retire the mask, stop coming to work and the revenant doesn't know who to target. Organized religion would have elaborate funeral rites revolving around putting the dead to rest. I imagine that revenants would be linked to divinity in some way - they are, after all, proof of magic and supernatural. Clergy would become very important - I'd expect a separate religious organisation revolving solely around putting the dead to rest. Also, many more weird funeral methods like feeding dead bodies to pigs, or volcanoes, or steel boxes under the ocean. Also, priests would offer final confessions and mediations to the dying, in hope of resolving any outstanding issues before death. There would be more social customs in place to try and prevent grudges from festering. And, finally, people will still commit suicide. If someone has a truly hated arch nemesis, then it'd be an old and dark tradition to take your own life - knowing that you'll come back and wreak vengeance upon them. It'd be like the ultimate beyond the grave fuck you. [Answer] ## Frame Challenge "1800s america[sic]" would not exist, because revenants would have existed since the beginning of humanity, so all of human history would have been radically changed. ]
[Question] [ Using resources already available at the time, could medieval age armies form their equivalent of a mechanized infantry and perhaps implement a sort of "blitzkrieg" strategy during battles? If so, how effective would they be? [Answer] **Not really.** Blitzkreig has lots of pretty pictures of fast-moving weapons, but the real power of the concept was based on *synchronization* and a short *decision cycle*. Weapons and soldiers didn't really move all that fast at all. Example: In 1940, it took over 6 weeks for the German army to reach Paris. *Synchronization* can be thought of as the use of pre-planned efforts by multiple units toward a single goal. Example: Multiple units working together across a hundred miles of front to cut off an enemy force and take thousands of POWs, supported by disparate air, artillery, armor, infantry, intelligence, and logistical units. *Decision Cycle* can be thought of as the enemy's response time to a friendly move. Having a shorter decision cycle than your enemy is a common way to keep the initiative. Example: If you begin air attacks on unprotected enemy forces, it's the time required for the enemy commander to learn about and understand the problem and bring in air defense units. Both require good staff work, a years-long system of (professional) military training to build staffs and trust and understanding, thoroughly drilled soldiers, literacy and printing for orders and maps, and reliable instant (or near-instant) communication across the battlefield. 'Reliable' communication is critical here - patchy communication tends to bog down offensives (see WWI) since you cannot effectively coordinate to overcome or bypass newly-emerging problems quickly. That's how you lose the initiative. Only a few medieval societies had the wealth to train and build such a force (none in Europe), none had the common literacy required, none had the concept of staff work required, and none had the necessary communication technology (radio). [Answer] # Mounted Infantry Cavalry comes in many variations, from knights with lances in full armor to light horse archers. There are two problems with cavalry: * Horses and armor are expensive to buy and to maintain. Especially heavy warhorses. * Cavalrymen will require plenty of training. A way around the second problem is to take infantry and to give them ordinary horses. These [mounted infantry](https://en.wikipedia.org/wiki/Mounted_infantry) are **not** trained to fight on horseback, unlike late [dragoons](https://en.wikipedia.org/wiki/Dragoon) who prefer to fight dismounted, but who were also trained to fight mounted. (Earlier dragoons were genuine mounted infantry.) With a "spearhead" of mounted infantry, a medieval army can [get there first with the most](https://en.wikiquote.org/wiki/Nathan_Bedford_Forrest#1860s) and later bring up infantry in support, much like German infantry divisions (on foot, with horse-drawn guns and supplies) followed the Panzer divisions. [Answer] The most famous example of "medieval blitzkrieg" was the Mongol armies of Genghis Khan and his immediate successors during several decades of the 13th century. Of course they were mostly cavalry who not only rode to the battle but usually fought on horseback as mounted archers and mounted lancers, etc., but they did operate siege machines during sieges. So possibly the Mongol army should be the inspiration for your horse-born medieval version of mechanized infantry. Or maybe there could be an alternate history where one of the civilized kingdoms in medieval Mexico hires Raramuri or Tarahumara tribesmen, famous for their long distance running ability, as mercenary soldiers to run to the battle zone and out maneuver their enemies like Stonewall Jackson's "foot cavalry" did during his 1862 Valley Campaign. [Answer] > > could medieval age armies form their equivalent of a mechanized infantry? > > > No, being limited to beasts of burden as source of power, there is nothing that can provide support to mechanized infantry. Chariot mounted archers were the closest thing to what you have in mind, but those are limited to fight in places where a chariot can move at ease. > > could medieval age armies implement a sort of "blitzkrieg" strategy during battles? > > > Not in the concept that we have seen during WWII. First of all, there is the lack of air support, then the cavalry cannot move in depth as much as mechanized infantry can (a truck moves as long as it has a working engine, transmission and fuel, a horse get fatigued), last but not least the logistic necessary to support the blitzkrieg was yet to come: medieval war relied on raiding the territories were it passed, and if you are busy raiding your dinner you cannot move further. [Answer] **The medieval age had plenty of examples of mechanized infantry.** The medieval period had several examples of mechanized infantry. The war elephant has already been mentioned. Vikings used their boats to approach an enemy target and disgorge an infantry unit very similar to the way an APC or IFV is used today. Of course, they were more limited on land, but did find their boats so useful as mechanized infantry platforms that they sometimes transported them miles over land so they would have access to them in a body of water on the other side. The best example of medieval mechanized infantry, however, like the Blitzkrieg itself, comes from Germany. Look up the Hussite **War Wagon**, the "Wagenburg". <http://www.thefewgoodmen.com/thefgmforum/threads/the-war-wagon.24186/> (Some good illustrations on this thread) A war wagon was used something like a mobile fortress, which is precisely the way a tank is used now. The wagon would be moved rapidly, positioned on some tactically important place, and then used to control surrounding territory and even in offense in conjunction with regular infantry (much like a tank, which can control an area, but can't very effectively take ground without infantry). The war wagon came out of the use of early hand cannon and similar firearms, and used this kind of high volume firepower and their inherent armor to hold positions, confine the enemy, protect cavalry, support infantry, and support sieges and other kinds of offensive operations. Czechs, Hungarians, Poles, Romanians, and Romani, as well as Cossaks were all reported to have used some variant of the war wagon tactic (undoubtedly learning it from one another as they warred over the years). <https://en.wikipedia.org/wiki/Wagon_fort> Mongols have been mentioned, but I would consider them to be very much cavalry. They were versatile light cavalry who could get off their horses and fight on foot if necessary, but I would *not* consider them to be mechanized infantry. If we go back a little farther than medieval times, we see the use of the war chariot in many different parts of the world. Ancient Assyrians would have a driver, an archer, and multiple infantry on each chariot, so the chariot would act like an APC and drop the infantry close to the action as well as providing fire support and protection. Ancient China used them in a very similar way, right up into the 400s CE. Using cool Chinese technology like the repeating crossbow on a chariot, you can have some pretty high volume firepower and a reasonably protected mechanized infantry platform, assuming you can armor your horse well enough. The Chinese also had what was known as a "Wu Gang Wagon" (武剛車) -which seems to be reasonably similar to the German version of the war wagon used later. So just there you have war chariots, war elephants, and war wagons, not to mention some of the amazing war machines developed for one off use, which we have examples of in some of the illuminated manuscripts from the time (they built everything from gigantic, bladed wheels to crush enemy soldiers, to multiple spear launchers, to rotating wheels with flails and chains designed to mow down entire rows of opponents, so boiling or flaming oil launchers of various types). Do not underestimate the mechanical ingenuity of the middle ages! [Answer] ### Yes, but not with land-based transport Substantial overland transport is a relatively new concept. Back then, people simply didn't do it. Roads were in poor condition at best, bandits were a real concern, and carrying any kind of weight or volume of anything (including weaponry) was extremely hard. Where you absolutely did see blitzkrieg in action though was in naval attacks. Various commanders (Drake is perhaps the most famous for it) devastated coastal towns. The ships' guns provided the equivalent of air or artillery support; and with the docks secured, the sailors and marines were free to land and raid the town. [Answer] Cavalrized Infantry not Mechanized infantry. If your aim is only limited on transporting your troops rapidly, this can be done with carriages, I believe there are already some medieval figures who did the same thing. Dragoons in a sense can be said a mechanized infantry as they can rapidly move over their area of responsibility. But if you plan to use them for blitz? On a limited area scale its probably using signal flags. The aim of blitz is for the enemy unable to respond to your rapid offensive using combined arms. Which in this case is quite limited to cavalry, infantry, heavy equipment [Answer] **African elephants are potentialy formidable weapons:** [![enter image description here](https://i.stack.imgur.com/t8VwS.jpg)](https://i.stack.imgur.com/t8VwS.jpg) *Attribution circusnospin.blogspot.com 2019* [Elephants are big](https://en.wikipedia.org/wiki/Elephant#Anatomy_and_morphology) (3.20 m (10.50 ft) tall at the shoulder for African bulls) heavy (4,000 kg (8,800 lb)) and fast reaching top speeds of 25mph (40km/h). They are intelligent and reliably trainable and have been used in wars for thousands of years (even way before [Hannibal](https://en.wikipedia.org/wiki/Hannibal) struck Rome). Once engaged they and their drivers are going to be difficult to attack and formidable at breaking through lines of cavalry or basic infantry. "Air support" would come in the form of what could be thrown or shot from the castle atop it - archers/slingers, even [greek fire](https://en.wikipedia.org/wiki/Greek_fire) bombs thrown. Once the lines are disrupted it'll then be up to your cavalry to encircle and trap the enemy - all the while the elephants will continue to trample and provoke terror in your foe. In no time your battle's over. ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 5 years ago. [Improve this question](/posts/130065/edit) My world is in a time period analogous to the 21st century. Within it, one of the main powers goes to war against a much weaker and highly politically unstable adversary (insurgency groups, revolutionaries, extremists, take your pick). The government justifies this invasion both as a "preemptive strike" and as a humanitarian mission to liberate the populace from... from their country's barbarity I guess? Doesn't matter. The actual reasons are complicated economic and geopolitical factors. But those don't matter either. Now from the start, the invading country faces discontentment from its own populace which only increases as the conflict goes on. But that's to be expected and it's manageable. But then, just before the war is won, things turn out really bad for the last wave, casualties skyrocket, units are caught completely off-guard by whatever tactics the losing side starts using. They still win, but instances of mental scarring, injury and death are very noticeably higher among the soldiers that served right before the end of the war than those who served anytime before. This doesn't include the occupying forces after the war's end: they're fine. Since this whole affair is being televised and reported on back home, the result is, of course, widespread anger and backlash against the government from its citizens (who as I previously said, weren't all too keen on this war thing in the first place), demands that various military branches be investigated for flagrant mismanaging the war effort, etc... Basically, it's a big scandal. **But assuming that the people in charge of the war aren't actually grossly inept, what could otherwise cause the war to suddenly become so traumatic for the winning side? What unexpected tactics might the enemy start using? And what would have prevented the invaders from predicting this chance in strategies?** Indeed, why would a war be the most traumatic and casualty afflicting for one side just before that same side *wins* the conflict? Surely if the losing party is capable of suddenly causing all hell to break loose, they wouldn't be losing at all, would they? The invading military works highly strategically and methodically to avoid loses on its own side as much as possible while eliminating the opposition. They're definitely not just blindly sending troops, on the contrary, it's highly adept at intelligence gathering and applying that information accordingly. So how and why would they suddenly find themselves completely caught off-guard by the enemy just before that same enemy loses? [Answer] Women and children start fighting. Imagine something like Japan at the end of WWII. Up to this point the army was fighting soldiers with weapons. As they enter the cities, they meet a different kind of opposition. Young kids with guns. Women charging at the army with hand-made spears. The remainder of the armed forces using body shields of people too young to fight and POWs. No one will surrender. To win they have to kill 100% of any city's population. This will demoralize any army. [Answer] The losing side becomes desperate, and switches from using formal military to guerrilla tactics. They brainwash their population to perform suicide attacks. At the end of WW2, Japanese civilians were known for committing mass suicides as US troops were about to occupy their town. But in your story, government provides civilians with both conventional and banned weapons for use on invaders. * Biological weapons, e.g. civilians infecting themselves, and then simply spitting on enemy soldiers. Or bringing infected ticks or lice into their camp. * Bombs implanted inside the body. "Pregnant" woman is a popular method. * Kids throwing grenades from rooftops. And so on. [Answer] **Urban or guerilla warfare** will do the trick quite nicely. Having been easily cut down in conventional battles, the losing side turns to asymmetric warfare to try to hold off the invaders. It's easy to see what makes this a desperation tactic: they're practically daring the attackers to destroy their cities, oppress (or displace, or simply wipe out) their civilians, and generally grind the nation into dust just to get them to *stop*. Even if the defenders "win", it could take generations for their country to fully recover from the damage the war causes. The hard part is justifying why the invaders aren't expecting this move, and why their response is so bad as to become a scandal. (There's no scandal in the counter-insurgent phase of an invasion being long, drawn-out, and painful to all sides: that's just how it is. But there's definitely a scandal in *gross* mismanagement.) Perhaps there was a generally-accepted idea that the defending nation didn't have it in them, politically or socially, to continue fighting at such a late stage: the attackers thought the government would give in much earlier, but it didn't for whatever reason (different leadership? a coup?) and now the resistance is much better organized, equipped, and motivated than anticipated. *Edit per comments* You indicate in your question that the invading military and intelligence apparatus is thorough, methodical, and very strategically-minded. This makes it unlikely that they *missed* preparations for a national-scale insurgency following a conventional defeat. Such a thing takes preparation and foresight, not to mention lots of people. It wouldn't remain a secret. So in order to be taken by surprise, either the intelligence community *misinterpreted* this information, or the military or political leadership willfully *denied* it. The former could be due to some kind of bias or unspoken assumption. If the attackers have spent years portraying the defenders as weak or cowardly in their propaganda, analysts might subconsciously believe it even if there's no basis in fact. Conversely, they might assume that the defenders will follow their own (that is, the attackers') beliefs and values. One theory about the ultimately disastrous Japanese grand strategy in WW2 was that they misinterpreted US strategy in WW1 as being primarily motivated by cowardice (as opposed to a combination of greed and apathy). The projections of their analysts therefore didn't match reality. The latter problem is mostly a matter of politicians and military leaders wanting the war whether it's practical or not. Perhaps the political climate is such that reasonable voices are being crowded out, or subordinate officers are rewarded for being "generous" in their estimation of their superiors' plans and their odds of success. The leadership might be focused on the easy initial stage rather than the difficult later stages. There might be a (perceived or actual) need to downplay the risks to buoy the morale of the troops or the civilian population. Whatever the case, although the leadership has or should have all the information they need, they don't reach the correct conclusion. [Answer] **Quite a few examples can be found in WW2** 1) **Battle of the Bulge** - In a last ditch effort at the end of the European theatre, the Germans threw everything they had in a last ditch defensive/offensive. So much so it took the allies by surprise forcing them to concede ground. The Germans marshalled the entire male populace from boys to the elderly in the operation. Naturally the body count was quite extensive on both sides. 2) **The Japanese** - So this was more the entire Pacific theatre but it certainly got worse the closer they got to the mainland. Basically, the Japanese cultural sense of honor was so intense that their fighting spirit completely shocked allied commanders. As they got closer to the mainland it quickly became honor and to protect the motherland. They would literally fight full force to the last man no quarter given or expected. --After WW2--- 3) **Afghanistan** - The western forces literally pancaked the Afghani military forces in like weeks. Yet the war raged on for years due to a modern form of guerilla warfare. The onset of modern media has made it so that public targets cannot be attacked without incurring huge sums of public sentiment. Thus this modern version of guerilla warfare uses civilians to camouflage attacks. This tactic only works because of the media because in the past such attempts were met with methodically cold acts of what would be considered today 'war crimes'. [Answer] There's lots of tactical arguments posited so far. I'd like to offer something slightly different. There's nothing quite as traumatic as one approaches final decisive victory than to realize you've been fighting on the wrong side all along. Perhaps the winners start to realize their mistake, but due to the inertia of nation-level combat, they are obliged to continue grinding away at the losing side, knowing exactly how history will write of them. History may be written by the victors, but that doesn't mean they have to like what they have to say. [Answer] ## The Fifth Column What if Hanoi Jane wasn't just an actress and activist, but also the face of a hidden army of militants lurking at home? When OPFOR's victory was still considered a possibility, this network of enemy agents tried to keep themselves largely hidden from public attention, sticking to covert operations like intelligence gathering and minor sabotage. Now that OPFOR's defeat is written on the wall, the fifth column decides to go out with a bang. They quickly arm themselves and openly strike high profile targets both military and civilian in the rear area. The supposedly safe homeland isn't so safe any more with the sudden emergence of a home front. Given that most of BLUFOR's troops would be deployed in foreign soil, the army will be ill positioned to stop this uprising. What would ensue is a campaign of terror waged against the winner's civilian population as the army rushes troops home to deal with this new problem. Inhumane tactics like those used by the Taliban and the WW2 Japanese can now be displayed directly to the civilians without the need for the media to bring these images home. This would create the mental trauma you need due to troops having to turn their guns on their own people, and the political scandal after the war ends. [Answer] At the start of war everything was under iron grip and went by great plan. So Army went from A to B and had good moral, logistics, discipline even part of enemy population greeted them with flowers in hand. But at the end of war that great plan went wrong. Flood/enemy general or they by mistake damaged huge dam, as a result soldiers and civilians die in huge numbers. All that is used by enemy to try and change the tide of war. They spread propaganda and start desperate atttack on cut off army. At the same time bursts festered problem of rear army: while generals had hard control on battlefront and routes of logistics, their reserve troops and mercenaries who were placed behind used lack off supervision to get rich sometimes even rape and kill. While it was rare and mostly covered, people knew. After the flood it spiked and under propaganda, it boiled off and started guerrilla warfare. So invading army had to deal with cut off army, flood, huge dip in moral, lack of land based logistics and loss of good part of supplies and over that desperate enemy counter attack and guerrilla warfare in the rear. [Answer] The defenders have weapons of mass destruction such as nuclear or biological weapons. So long as they thought there was a chance to win they didn't use them, but once all hope was lost they deployed them in one last ditch effort not caring for the consequences. [Answer] The winning side has had good and reliable evidence that the military campaign was against, mindless clones and programmed machines. The civilians believe this too, the evidence appears legitimate to everyone (almost) in power, everyone on the ground, and every civilian. The war effort progresses, side A winning, not an out right victory but no slog either. Everyone is wishing to put this all behind them. While the war effort has been underway, many civilians have been recruited to work in factories, bio-labs, etc... manufacturing war-machines, and researching the means to heal wounded soldiers, such as cloned-limb replacement. Suddenly the forward march of the army slows, the machines have gotten tougher, the clones smarter. They start to loose some ground. Nothing too serious but definitely alarming. The military reorganizes and plans an ultimate assult on those last strong holds. The factories work in overdrive, the labs grow tissue like mad. Everyone has pulled together to make this offensive possible. The machines are second to none, the tissues are super-enhanced. D-Day. Guns pound the ground, missiles launch, tanks grind over walls, nothing but blood, death, and cruel land-acquisition. The battle is the worst yet, no one makes it out without some wound - but the day at last is won. But there are questions now. How did the loosing side, so clearly under-resourced, so clearly out matched, suddenly field such a an almost overwhelming display of power. If it had of been unleashed even a day earlier they wouldn't have won. In move the investigators, they pour over the technology they just defeated. They fly in experts from the factories, from the labs to analyse and assess. A technician realises with horror what the twisted wreck of iron and flesh in front of him was. He had designed it himself. News is reported back to the home land. How did the finest military equipment, built by the finest engineers, get used against their own forces... [Answer] Maybe as an alternative: what if it isnt the enemy that causes the trauma? Its basically mandatory since early history to always make the enemy the bad guys. Even the Nazi's made it seem that their atrocities were justified to the people executing those orders and the lesser atrocities to the entire human populace. The Americans in the civil war fought openly for slavery and in Vietnam the coming of independent war newsreports revealed the atrocities both sides commited in the war. In your scenario the tired, jaded soldiers might celebrate their victory through looting, rape and murdering of prisoners. They might "pre-emptively" find and kill people who they deem a risk of becoming guerilla's or they might simply look for extremists and legitimate threats and execute them without due process, scarring the countries idea's of why they fought there. [Answer] The weaker side, anticipating total defeat, used weapons that were illegal or thought too horrible to use. This can include nuclear weapons, poison gas, and weaponized anthrax. The stronger side has kept the fighting more or less in the countryside for as long as it can, but concludes it has to take cities to finish the war. They find the cities very well prepared for defense, with lots of extra defenders. They're not very good and only have personal arms, but they can still be quite effective defending in a city, and their morale is high because if they lose their country is conquered. There are also lots of booby traps prepared, as the conquest has been predictable for some time now. The invading commanders had been aware of this possibility, but had been putting it off as long as possible in hope of getting a surrender. The weaker side managed to talk another country into an alliance late in the war, and the third country gets into position to fight shortly before the end, operating with considerable stealth to surprise the invaders. ]
[Question] [ I want to create a post-religion society, but the problem is that the rest of the world still have religion. How could I assure that my society remains religion-free while allowing tourists and trading? Possibly even immigration? I'm thinking about making religion illegal or at least something that is seen with lots of despise on my society, but that would make the others nations to look bad on this nation. On this society, religion is only allowed on your own house but nobody really practice that, and the public education teach the children all the evils that religions does. It's a nation of people that agreed that religion brings them nothing but ignorance and terrorism. But how to ensure that immigrants and tourists won't came and spread their religious ideas ? How to stop the "external" world to infect this nation with religion? [Answer] I believe your question raises a few other important topics and questions which you may want to consider when defining the success factors of such a society, so I will split my answer up accordingly: ## Trans-cultural diffusion If your citizens live in a modern world, particularly a world with cheap, ubiquitous and uncensored global communication (e.g., the internet), your success at establishing and strengthening your society will depend on your society's [cultural influence](https://en.wikipedia.org/wiki/Trans-cultural_diffusion) (a.k.a. trans-cultural diffusion), more so than any laws you put in place to curtail the open observance of religion. ## What kind of government do you run? You've mentioned you will allow religious observance in private homes, so presumably you would not require any sort of Orwellian [Thought Police](https://en.wikipedia.org/wiki/Thought_Police) (generally regarded as a bad career move, politically speaking!) Is your society a country? (Given you intend to global trade, immigration, and set broadly-scoped laws that would impinge the constitutional rights of many current world nations, this seems likely.) If so, is it a democracy? Or do you spread your society's beliefs via dictatorial rule and military might? (Unfortunately numerous precedents exist even in modern world history.) If you are democratic, then the need to "sell" your anti-religious beliefs to your people becomes as important (if not more important) than convincing outsiders. How your society (and its leader) came to power is another equally important topic. Did a large number of like-minded people get together and create a cultural movement large enough to earn real power and influence (and presumably land) in the world? Or did a small number of people use fear and/or brute force to carve out a bastion of power defiantly standing against all the bad, nasty, evil religions in the world? ("Infidels!") ## Can we come up with a better name than "post-religion"? What's in a name? perhaps, but given that you seem to want to (and need to) *sell* your ideals to your populace (and, likely, the world, if you do not want your borders and population to shrink over time), a good name might go a long way. "Post-religion" does have some interesting connotations (c.f. post-secularism), but even with some very creative propaganda, pundits in your world will likely be quick to point out that your country is, in fact, anti-religion (as Cyrus has insightfully already mentioned). Perhaps that kind of tension is precisely what you want to create, but if it isn't, think hard about the image your society wants to project. Often, being *for* something is easier than being *against* something else. Would a "secular society" or a "scientific nation" be better received by your world community? ## How far would it go? A self-proclaimed "non-denominational" school in Calgary, Canada [was recently fined for refusing to let students pray on campus](http://news.nationalpost.com/news/canada/private-school-that-forced-muslim-students-to-pray-outside-unlawfully-discriminated-human-rights-tribunal-rules). While your fictional country would presumably be free from legal and civil actions such as this, the article I've linked does highlight some of the practical problems with attempting to keep religious practice out of public, out of schools, the workplace, etc. What lengths would your citizens have to go to in order to observe their religions? What lengths would your government go in order to stop them? If your society is extreme enough, it wouldn't be hard to imagine the ultimate consequence of this to be a holy war, which is pretty much the definition of one group enforcing the idea that their beliefs (or in this case, the vehement lack thereof) on someone else. ## Conclusion Hopefully the above talking points will help you (fictionally) mold this society according to the story you want to tell. Importantly, it does seem from your question as though your society wants to spread the influence of your "one true God". The fact that your society's "God" is an affirmative lack of religion doesn't actually change the equation that much from a practical point of view. My advice would be, to consider what kind of socio-political parameters your "religion" will have: For example, some religions are welcoming, some are not. Some are tolerant, some are not. Some reject science, some do not. Then, look for real-world religions with similar parameters (regardless of actual beliefs), and look at how adherents have historically spread those religions, *and* how those religions market themselves today. [Answer] The way you describe your society makes it anti-religion rather than post-religion. If your society provides its citizens with safety, prosperity, education, a sense of belonging and a sense of purpose, religion will not draw large groups of people and you don't care if a handful are religious. People lacking those things feel or fear there is no place for them in this world, so they will look for one. Religion provides a group to belong to as well as answers to the big life questions (Why am I not safe, healthy and happy?) Examples from real life: * Early humans faced mysterious and powerful dangers at every turn. They developed the idea of gods and spirits to figure out why and to feel yhey could at least bargain with if not control those forces. * Extreme poverty means people see no future for themselves. The idea that this life is just a stepping stone to paradise keeps them sane. * Being rejected by society (for being different) makes people question their identity and look for a group where they can belong. * If people lack or lose their sense of purpose in life they will start looking for it. The whole spiritual wave of the New Age was a good example. Suddenly people had more than enough wealth, achieving the primary goal inherited from previous generations. Then they felt empty and felt there had to be some different purpose in life. Note: Communism was very anti-religion because of Marx's observation that "Religion is the opium of the masses", i.e. religion kept the masses happy despite oppression and poverty. Marx and the communists expected that communism would make people happy and religion would melt like snow in the sun, but that didn't happen. At all. Rather than recognize that religion was also very important to people on a personal (spiritual) level, they saw it as an embarrassment that contradicted Marx' predictions, so it had to be stamped out by force. 100 years later, all those communist regimes are now gone (with the exception of China), the religions are still there. Consider that carefully if you want to stop religion by laws and force. [Answer] Forbidding religion only makes it stronger. It also makes your society into a police state. Don't go that way. It is better to look at WHY you want your society to be religion-free and work towards those ends directly. For example, if you want to prevent terror, don't make a habit of bombing civilians in foreign countries. That sort of behaviour tends to make people angry at you. If you want to prevent ignorance, make education cheap. As part of that education, teach kids about all the religions of the world, and how they can't all be right at once. If you get religious immigrants, you can't expect to convert the parents, but try to reach the children. Try to avoid religious groups collecting in ghettos where children can get the impression that "everybody thinks that God is real". Bus children to different schools if necessary. Many religious groups make it hard to leave them with parents disowning their children and other ugliness. Publicly condemn this sort of behaviour and make sure the victims get good support. The battle against religion should be fought on many fronts. [Answer] There are a few issues that you will have to resolve based on your question and your comments. 1. The Utopist's Fallacy: the government cannot provide all the things you describe *period*, much less by simply banning religion. 2. Religion is not the ultimate source of racism/homophobia/etc., studies on infants and children have shown that we are *hardwired* to be prejudiced based on noticeable differences (Time magazine had a rather inflammatory cover reporting this with the title 'Your Baby is Racist') and that it takes deliberate training to overcome this natural tendency. 3. The limits of Law and Order: as other answers have pointed out, it would be both draconian and pointless to even *attempt* something like banning religion (obligatory comparisons to Communist societies have already been made). So I don't really find your proposed society to be believable as you've described it. I could easily see a group of people in a country (small town?) deciding amongst themselves to such precepts, but I don't think this sort of thing would scale up to that size. If your going to create such a society where people *believe* in those fallacious assumptions you will have to explicitly deal with the conundrums to make it believable, i.e. its a young society that's attempting this (and you will have to deal narratively with the inevitable failure). They will have to be zealots who ignore the rational counterarguments, etc. Unless you are pandering to an audience who themselves believe in those fallacies, in which case yeah, blow whatever smoke at them they wish to inhale. # EDIT After re-reading my answer, it sounds too much like a defense of religion. My point is not whether religion is good or bad. My point is that even if you start from the premise that religion is bad, it isn't the *only* ill to plague society. You can't be all hand-wavy about every social problem because you banned religion, people won't buy it (unless as I said above they're already strongly anti-religious). # Second Edit Based on OP Comment I'm not saying a nation can't become officially atheist. Its *happened*. I'm saying it can't *stay* that way forever. You're asking for a post-religious society where the populace has moved beyond religion. That (in itself) is believable (with caveats), but you're also asking for how that society would interact with societies that are *still* religious, and that's what makes in unbelievable. The only way to have a believable post-religious society is to have one where you make it clear *the vast majority of rational persons* would not be believers: i.e. religion has been relegated to the fringes of humanity *as a whole* (not just one nation). That's what 'post-religious' *means*. Otherwise, you run into the 'thought police' or totalitarian state scenarios mentioned in the other answers. That repudiation of religion hasn't happened in your hypothetical scenario, based on the existence of other, religious, societies. In the end, no nation-sized group of people will be able to go against the flow of the rest of humanity for more than a handful of decades at best (smaller groups maybe?). That implicit contradiction is why, IMHO, you're getting all these answers with a TL;DR of "it won't work". A real-life example of just how hard it is to live a life radically different than the rest of humanity might be the Amish. [Answer] In order to make your society not turn to other religions, you need to make it like a religion. If non-religion is actively practiced in schools, is entwined with the infrastructure of the country (symbolism on money etc.) then it will automatically become a way of life for people living and growing up in that country. Most religions have lasted for so many years because they offer people something, such as a sense of belonging, a kinship with others, and a spiritual satisfaction that makes people feel happy and content. Obviously people would want to continue this feeling, so would have no reason to leave, thus your non-religion would in some way need to offer these things, or people will begin to look elsewhere. Although everyone is an individual, you can't force people to practice a religion (or in your case, not), but if it is highly frowned upon in society then people would be less willing to pursue a religion without preferring to leave the country in order to be with like-minded people. Missionaries *will* come to your country if it offers free travel, thus the important thing would be shutting down underground religions that are trying to take root anywhere. Harsh punishments will lead to other countries claiming religious persecution, so the punishments would simply have to be fines etc. for establishing underground places of worship. Some religions ensure that they keep their members by banning them from reading anything critical about it, in order to keep them ignorant from any flaws in their belief system that may cause them to become disenfranchised. This would not work for this society unless the country had blocks on religious internet sites, so would be difficult to maintain on a large scale. As for the establishment of such a society, it would likely start from a mass tragic event that would cause everyone in the country to despise all religions (rather than just one), which would cause everyone to suddenly disbelieve their religion, or make anyone who does believe feel very unwelcome in the country, perhaps to the point of [evicting them entirely](https://en.wikipedia.org/wiki/Expulsion_of_Asians_from_Uganda) (I know that that example is a race and not a religion, but it's the only example I could think of). In summary, it would be almost impossible to ensure that *no one* in this society is religious without being North Korea or getting dragged before the UN human rights committee, but there are many things that you can do to minimize religiousness. [Answer] **Remove the need for the crutch and people will stop using it.** If you can build a country that provides: 1. Safety 2. Health 3. Education 4. Prosperity 5. Cummunity 6. Purpose Then people will abandon religion. Almost as important is what you do not do, primarily **do not** use fear to control your population. It's not that shocking that non-religious populations are highest in first world countries (ones which provide or make available all the items on the list). A notable exception is the US, but that is likely due to the prominent culture of fear. Basically, you have to be an objectively awesome nation. That's nigh impossible to do with human politicians. With an AI government and people educated enough to understand that evidence trumps faith, such a thing is possible. > > "Religion is something left over from the infancy of our intelligence, it will fade away as we adopt reason and science as our guidelines." - Bertrand Russell > > > [Answer] This has been tried at least four times in history: The French Revolution, the Soviet Union, Mao's China, and Pol Pot's Cambodia. The way you do it is by making religious belief a crime. Anyone who is caught practicing a religion or trying to spread a religion is tortured and killed. You burn down churches and ban all religious books. You indoctrinate children to report their parents to the police if the parents try to teach religion to their children. You form a secret police organization that spies on everyone. In general, create a climate of fear and suspicion. The media and the schools must be subject to rigid censorship to keep out any dangerous religious ideas. If people are allowed to hear opposing ideas, they may find them persuasive and abandon the official government line. History books must be re-written to eradicate any references to religion. At all costs, the people must not be allowed to ever think for themselves. You might want to investigate creating a new language -- let's call it "Newspeak" -- that doesn't even have words for these dangerous concepts, to make it more difficult for people to even formulate such thoughts. [Answer] You have to remove "freedom of association" and "freedom of conscience" for your society to effectively restrict the religious practices of its citizens. You can write a fictitious story where your citizens are happy to give up these human rights, but it will not be believable, so I don't think there's really any point in asking the next question you pose here - how to prevent cross-contamination from the rest of society. That being said, there are works of fiction that have become popular discussing such dystopias - and yes, the society you describe can only be thought of as a dystopia. For instance, in [The Giver](https://en.wikipedia.org/wiki/The_Giver) society is forced into a structure of limited knowledge, and no contact with the outside world. Another similar dystopia, [Divergent](https://en.wikipedia.org/wiki/Divergent_(novel)), supposes a society cut off from the rest of the world by a wall. They have no information about what's outside the wall, but they have broken into factions that celebrate exclusive/inclusive human traits which effectively break people up into groups. Religion plays no part, but many of the things that make up religious views and fervor are caught up in the faction system. Most logically consistent books that don't "make the others nations to look bad on this nation" adopt an insulated society. If your society cannot be insulated, then you really only have one option: violence. If you force visitors to abide your rules, and you force your citizens to abide your rules, then you can, to some degree, prevent some religious activity. You won't be able to realistically reduce it to zero, though. [Answer] **Incompatible terms.** Post religious cannot be "within" religious. "Post religious" is natural gradual maturation of significant part of planet's society that activates self actualization perspective within context of Planet and Cosmos. It's the next evolutionary step for race and naturally does not suddenly occur as large segment of individuals having way more advanced maturation than the majority of population. **How does it look like.** Post religious society is the one that is spiritual and psychic. It is socially responsible, educated, technologically advanced. There is no distinction between physics and spirituality. Religious identifications with ancient stories and idols seem outgrown history with bitter past. These people have empirical super conscious experience and do not have need to rely on external authorities, ideologies and political dogmas, hence there are none of these. Planet's resources are used to sustain needs of people. They don't need to pay for anything, living, food, health care, education - all is free. Nobody really owns anything valuable, there is no "property" concept. But they use transport vehicles and other things for free, it's public. No social divisions, just skills and individuals with different maturity/consciousness levels. Everyone may choose to have duties and be useful to society. Majority does. Experience and skills may give them more responsibilities in society or projects. Birth control is regulated. There is general support, safety and freedom feeling to express oneself to full potential. [Answer] Look at Europe or China or back at the USSR or North Korea as flawed prototypes of what you are looking for. Seriously. Instead of having some deistic religion, the people can have some philosophic or cultural religion or a cult of personality. A society can't be non-religious or post-religious. A human heart is designed to worship. Just find something else for the society to admire, focus on, and strive and grasp for (Examples: the pursuit of material gain or hedonism). ]
[Question] [ **Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/232373/edit). Closed 1 year ago. The community reviewed whether to reopen this question 1 year ago and left it closed: > > Original close reason(s) were not resolved > > > [Improve this question](/posts/232373/edit) Assuming a planet of similar mass and atmosphere as earth, how much and how often do I need to add orbital debris to prevent space travel? [Answer] This is my second most frequently used quote on this Stack: > > Space is big.Really big. You just won't believe how vastly, hugely, mind-boggling big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space. Listen; when you're thinking big, think bigger than the biggest thing ever and then some. Much bigger than that in fact, really amazingly immense, a totally stunning size, real 'wow, that's big', time. It's just so big that by comparison, bigness itself looks really titchy. Gigantic multiplied by colossal multiplied by staggeringly huge is the sort of concept we're trying to get across here.(Douglas Adams, *The Hitchhiker's Guide to the Galaxy*) > > > > > > > All the crapola that humanity has put into orbit in the last 70 years hasn't made a dent in our ability to launch ships. But what really stings is that you can't just dump trash — you'd need to actually power your orbital constipation. **The natural spin of things creates rings** If you put enough stuff into orbit that it would stop launches, that stuff would begin bouncing off each other like a drunken llama at a rave. You see, all those stable orbits in places other than the equator exist in no small part *because nothing's getting in their way.* As soon as you start introducing chaos, the result is for things to settle down and get swept along by Earth's gravitational tidal forces. Into rings. Oh, it may take a bazillion years, but it would happen. The only way you can avoid that is to make your blockage *intentional* with powered satellites that remain in their assigned courses to ensure no launch can happen. And if you're going to do that, you might as well save yourself some dough and simply arm some of the satellites so they can shoot down the launches. **But I love the idea!** And why do I love it? Because everybody on the planet would be *constantly* dodging bits and pieces falling out of the sky. It would create an entirely new cottage insurance industry. It would also cause a boom in investments into geothermal energy, because enough stuff in the sky to stop all launches would (IMO) seriously block out the sun. That means growing mushrooms in caves located under the Yellowstone Caldera to feed the people. In the meantime your civilization devoted to blocking the planet's inhabitants from leaving has made me rich because I sold all their stock short due to the economic depression caused by the cost of moving so much junk into another planet's orbit! I mean, think about it. How much junk would you need to drop onto the surface to keep people from driving their cars? Now multiply that by a bazillion because the surface area in low orbit is so much larger than the surface area on, well, the surface. Big. Really, really, really big. [Answer] **No** It may be possible to use Kessler syndrome to stop them from placing stable orbiting satellites (see: [Can I render satellite deployment impossible, or at least impractical, by exploiting the Kessler syndrome?](https://worldbuilding.stackexchange.com/questions/147375/can-i-render-satellite-deployment-impossible-or-at-least-impractical-by-exploi/147376#147376)). I have an answer there calculating that a deployment of around 12,000 is the minimum for LEO only. To stop people being able to *leave*? Nope. The escape vector to leave a planet you need a very slim window to directly go through which you can't stop outside of a Dyson-sphere like construct, which isn't really a satellite at that point. Sure, maintaining a stable orbit isn't really viable and without stable orbits, space flight isn't that useful, but you can't stop space travel just by caking a planet with a minor debris field. Not to mention that space is *huge*, there's not really an effective way of stopping a satellite with has decided to orbit past GEO. Sure, it's not a great place *to* orbit, but it can orbit there. And, remember, once you start oversaturating the debris field, it will hit itself and start knocking itself from the sky, so there's a limit to how much you can saturate that, [Answer] Short answer it won't work Reason for that is that at 200km orbits things deorbit quite fast, but it still a viable orbit just more expensive one, from which one can sync with stuff flying around and leave the orbit. * different attack and counter attack strategies are possible, but it pretty much all the same as a result debris is not that effective. It means you have dump a lot quite often and this may be a more of an attack on the surface of the planet as effects go - so in a sense it easier to kill all the life on a planet than block space travel by debris. Active means like sleeping missiles are much more effective [Answer] Based on other answers saying it's basically impossible to do what you want to do, here's my suggested evil space overlord alternative: Assumptions: the evil space overlord does not want the civilization to know this is happening. He just wants them to think that space is really dangerous and full of small rocks. The evil overlord also has some kind of scanner/radar-type technology that the civilization is incapable of detecting. (I feel like these are reasonable assumptions otherwise why do any of this. Just shoot them all down blatantly.) 1. Find out how small of an object the alien civilization can track. NASA currently tracks objects "as small as 2 inches" in low earth orbit. Let's assume the civilization is at the same level here: 2. Litter a good deal of 1 inch debris around. 3. Throw in a lot of space guns that fire 1 inch pellets at tremendous velocity. The idea will be that the civilization will encounter the 1 inch debris and while, as per other answers, it's not able to be dense enough to *really* create a reliable hazard, it's dense enough that they will notice it. The guns will then fire on some rule basis: * Any ship reaching velocity to escape the planet's gravity well gets shot. "Oh wow bad luck we managed to hit one of those little rocks and it went straight through the engine." * Any ship in orbit gets a random chance to get shot, per day. It's a low chance but nothing stays in orbit for years without taking multiple hits. We have created a vague hazard that's impossible to accurately track and then weighted the die by setting up some guns, which just look like debris, that will fire automatically to keep the threat inflated. It will probably really confound their scientists but short of discovering one of the guns it should keep them contained and befuddled. Might even be most governments just opt out of the space program because it's "too risky" and public sentiment turns against it. ]
[Question] [ Imagine an alien race that's advanced enough to wipe out humanity. They are here and they want Earth. They know we are not gonna let it go easy 'cause they've studied us for decades. Their motivation isn't relevant, but they **need** our planet for some reason. Their objective is to exterminate humanity but they can't harm our home - at least not beyond repair. This means that: * Nukes are out of the picture; * If possible, they will not harm any other species; Assuming they have very advanced technology, **from a strategic point of view, what would be the best way to eliminate us as quickly as possible?** Imagine you are the alien commander. What would your tactics be? Kill the electronics with EMP's to disrupt communications? Bombard major cities first to avoid blowback? Spread known diseases like the black plague to kill them from within? The ideal answer must take into account the vastly widespread human population and the many nations with their own military capabilities, 'cause people will try to fight back - or hide. I'm changing the original statement that all humans must die. I can settle for 99,99% - **in a way that it's impossible for humanity to ever recover**. [Answer] If they have studied us for decades they can use our DNA, design a virus that targets specifically humans, uses birds and plants as a natural reservoir and is 100% lethal. If some people develop immunities, you can use more advance weapons such as kill sats or swarms of nanobots killers or just conventional weapons if you managed to make enough chaos to destroy any form of resistance. [Answer] Infiltration, prior to extermination is the only safe tactic. The indigenous humans have created too many deadly devices, (some of which, like nuclear power plants, require constant maintenance to not fail catastrophically) to safely depopulate the planet without ramifications. Beyond the direct threat of their technology, your mandate not to harm other life adds an additional complications. Humans imprison a variety of other species in zoos and food-factories and without the intervention of humans, those innocent prisoners would starve to death very quickly. So the only way to fulfill your mission is to first infiltrate the human population and put your operatives in all of the key maintenance positions. Then and only then, can you safely release the highly-contageous, symptom-free, species-specific deadly viruses which will handle the actual killing. [Answer] What you need is pinpoint accuracy, Nanobots is a good way of doing that. A swarm of Googolplex (yes that's a real number, 10^(10^100)) coming down from the sky and munches away on all the human cells they can find will make short work of humans while leaving everything else untouched, the reason I think nanobots will be better then a Bioweapon is that viruses\bacteria can have immunity by a small percentage of the population but I've yet to meet the person who's immune to being bitten by a hoard of microscopic mouths (or drilled with microscope drills, or cut with microscopic saws, or... you get my point). We could try to fight them with EMP's and such but to be honest any alien that has the technology to travel to earth can likely also manufacture those tiny buggers at such speed and quantities we will all be dead before the first scientist will have time to put one under a microscope. [Answer] ## Disease Think about the advantages: * It can be engineered to affect only humans, leaving all other organisms unharmed. * It is extremely efficient, feeding and replicating itself without any input from you. * It can be engineered to be airborne, thus speeding contamination and replication, and making containment extremely difficult. * It can be engineered to be resistant to cold and modern medicine. If some sort of quarantine is set up fast enough, just drop it in a few places. It cannot be beaten. * If you have the ability to engineer the perfect disease, you likely have the ability to engineer another disease which can quickly eradicate it from the planet, just as easily (if necessary for some reason, once all the humans are dead, of course). Instead of trying to outgun Earth and leaving giant craters everywhere, or trying to cripple our electronics, just sit somewhere in space the humans can't reach you, and engineer a breed of these microbes, keep a few in containment for backup purposes, and release the rest in high-population areas across the globe. For maximum spread, give it a very high incubation period, allowing it to be spread fully before any symptoms manifest themselves. To be especially tricky, make it mimic another disease or condition, thus delaying its proper identification even more. There will still be pockets of isolated humans, especially those living on small islands. To fix this, engineer the disease to be carried by other animals, without affecting them. There are examples of this in nature (reference needed). Birds are a good candidate, as are fish for the above-mentioned islanders. Dogs could work well for isolated survivalists. There will still be some final hold-outs, filtering their water and raising their own food where your disease can't get at it. You have two ways to get to these final survivors: either destroy them with superior weaponry, or engineer your disease to be carried via various ground mites, and thus under any walls the survivors can put up. Inevitably, you will miss some humans. They might hide out in sealed rocky caverns or old cold war bunkers. They might even keep the species alive. It doesn't matter. They'll eventually run out of space/food/oxygen, and need to surface. And when they do, your disease will be covering the planet like an invisible blanket, just waiting for the last humans to raise their heads and take a whiff of air. In the end, disease is the ultimate killer. If we can't stop it and we can't contain it, then there's nothing we can do. --- Others have raised valid points involving the humans' deadly weapons. I don't think this is a concern though, if they never have the opportunity to use them. If you're attacking via disease, you don't need to be orbiting Earth. You don't need to be close by at all. Just launch the microbes from afar, while hiding behind a planet/moon. The humans won't even know that aliens are involved. Even if they do somehow spot you (and even then, they have to be looking for you first if you're hiding), they can't get to you fast enough. Assuming that we're talking about modern day humans, any missiles or ships they launch will take days, months, possibly even years to reach you. You have plenty of time to detect any threats and blast them from the sky... er, space. Another excellent point was mentioned by Henry Taylor, about the machines requiring human presence, and the animals stuck in zoos requiring feeding. This is the one problem with the disease scenario. It's going to be impossible to save every domesticated dog, cat, and bird, so some animals *will* die. This should be acceptable. It's very far from eliminating a species. If you're really bent on saving as many animals as possible, the zoos are your best bet. Send down landing craft at the biggest ones once the humans are too weak/dead to do anything about it, and take over. There might be some resistance, but this can be dealt with by developing a fast-acting strain of the virus, which kills within hours. All humans within a ten mile radius of the zoo are bombarded with this strain from space, and subsequently die before they can do anything. One problem with wiping out all humans is that certain dog breeds - specifically those with short legs, are going to be in trouble. These dogs were bred for aesthetic purposes, and won't do well in the wild when in competition with their more able cousins. Unless you start adopting these dogs, they *will* all die off eventually. Another problem of killing all humans is the machinery which requires us to keep running. Even if the worst happens and these buildings turn into a gigantic ball of flame, the affected area is quite small, and the damage to the planet definitely won't be permanent. In all likelihood, all animals have long since fled from such industrial areas, so the effect on the fauna will be minimal. And if there is machinery you feel you simply *cannot* let blow up... just send down a landing craft and stop it. What about nuclear power plants? According to [this question on this very site](https://worldbuilding.stackexchange.com/q/38018/6620), those are unlikely to go off, and even if they do, they will not turn into atomic bombs. Worst case scenario is something like Fukishima, where radioactive material is leaked into major ocean currents. And again, if something like that is about to happen, send down a landing craft to stop it before it does. ## tl;dr These three things: the ability to hide, the ability to send down landing craft and take over for humans where needed, and the ability to create and manipulate viruses, are all that you need to effectively wipe out all humanity. You will not find a more cost-efficient or nondestructive method. [Answer] ## Aim for anything hot The problem with trying to get rid of *all* humans is the increased difficulty of even finding new targets when the human population gets small enough. Killing the first 3.5 billion humans is easy since 50% of humans live in or near cities. From orbit, just look for the big patches of light on the planet's surface. Throw big enough rocks at all those lights and you've killed half of the humans in fairly short order. There's a huge loss of animal life with this approach...oops. Wait a few months then look for all sources of heat on the planet surface, especially after night falls. Develop a 1 meter resolution profile of hot and cold patches on the surface. Forest fires, geothermal, radio-heated and other 'natural' heat sources will have distinctive signatures so you can ignore them. However, human cooking fires should be visible from orbit or from high altitude surveillance aircraft. Launch orbital strikes with terminal guidance capabilities at those cooking fires. Maintain a long standing campaign of this kind of bombardment. Humans have evolved to be dependent on cooking their food. If they can't cook their food, they have less time to spend foraging, hunting, rebelling. Their time is spent chewing. Lots and lots of chewing. Eventually, the humans will learn how to cover their cooking fires so that they don't invite attack. Hunter gatherer humans will be much harder to track but at this point, human activity essentially doesn't matter anymore. Modern h. sapiens have been pushed back 5000 years of progress. It will be a very long time before they can come back. In addition to the cooking fires, most modern machines produce heat so aim your orbital projectiles at those heat sources. Trucks, trains, cars, factories, refineries, power plants...all these produce heat. Aim your orbital projectiles at these heat sources and you'll drastically reduce the available machines that humans can use. ## Advantages All of this can be done from orbit. No need for a messy, expensive ground campaign. And as the aliens, you've got all the time you need to finish the extermination. Your preference for not killing wildlife means you want the biosphere for something; indicating long term interests in the planet. You've got time to wait. [Answer] If your aliens aren't in a hurry, the easiest way is to release a plague that causes everyone to become sterile. This [technique](https://en.wikipedia.org/wiki/Sterile_insect_technique) is used by us to eliminate problem insects. Google's parent's company, Alphabet, is using this technique to [combat mosquitoes](https://newatlas.com/verily-mosquito-release-wolbachia/50521/) in Fresno County California. **Advantages** * Without reproduction, a species will become extinct within one generation. * The onset would not be noticeable. The victim would experience a mild fever, body aches, maybe some fatigue. The symptoms would resolve in a few days. The first warning medical science would have of the seriousness would be a statistically significant drop in births (The US Federal government notices statistical drops in births from a single Ob doctor retiring in a rural hospital.) By that time, it would be impossible to try to contain the contagion. * The aliens don't need to infect everyone. If 75% were affected, the human race would be extinct. * Society would collapse long before everyone dies. As folks age, [huge issues](https://www.economicshelp.org/blog/8950/society/impact-ageing-population-economy/) will rip apart societies. With no younger workers to support and replace older workers, social services break down. Famine and disease would kill billions. * Only humanity will be impacted. Animals would be unaffected. No residual radiation, * After 120 years, 99.99% of the human population would be gone. Pockets of folks who didn't get infected would be living in small tribal groups, far away from any population centers. These could be mopped up without any worries. Disadvantages * It's slow. It would take between 40 and 80 years for the existing population to die off. * It gives humanity time to seek reprisals, if in their power, against the aliens. While humanity can't even go to the next star, and since any alien species which can master FTL would be mostly immune from whatever feeble attempts to attack them, it would be conceivable that humans may decide to render the Earth unuseable after their gone. [Answer] **All of the above** The problem is humans are clever, and can adapt faster than you might expect. So hit them with several different methods of extermination in rapid succession. First, release a virus or set of viruses that target popular food and feed crops, give that a few months to start taking effect. Make them start using up their food reserves. Then, release your anti-human virus. Weakened from food shortages, humans will be more vulnerable. A good virus should have a *slow* onset, so that carriers can still travel and infect others. You don't want a quick acting virus, you want it spread around before they realize what happened. Give this a few weeks or months to maximize distribution. Then, pummel their cities and infrastructure with rocks from space. This will make it difficult for them to research cures, spread remedies, and coordinate emergency response. You want to do this *after* releasing the anti-human virus because you want that to spread quickly, so you still need their transportation infrastructure in place. Now sit back for a few months and wait for the ones not killed by the virus to starve. Finally, hunter/killer drones and a few additional well placed rocks to pick off the pockets of stragglers. For those small, isolated human populations who were not discovered by modern humans, you can safely ignore them. For now. This strategy shouldn't scar the Earth too much. You'll get a lot of craters where cities were, but you were going to clear those out anyways. Nature should take those back over fairly quickly. [Answer] The story [Screwfly Solution](https://en.wikipedia.org/wiki/The_Screwfly_Solution) proposed this. It was based on a pheromone used to kill off screwflies by making the males attack females. Within a generation there are no viable humans remaining to breed, so look! Empty real estate! [Answer] **Dust with prions.** [Prions](https://en.wikipedia.org/wiki/Prion) are infectious proteins. They can infect by just about any route including aerosol or ingestion. They persist in the environment for decades. The neurodegenerative diseases caused by prions are invariably fatal. The incubation period is months to years. The planet will be dusted with prions from the air. Multiple dustings will take place. Prion protein will be everywhere - in the air, food and water. The humans will be unaware of this because prions are not intrinsically toxic, but over the course of multiple dustings, every human will be infected with prions one way or another. Once people begin falling ill it will be too late to do anything about it. Prions can cross infect other animals to some degree; some humans contracted mad cow disease. I think many primate species might also be wiped out by the prion dusting approach. [Answer] [Death from the Skies](https://rads.stackoverflow.com/amzn/click/0143116045) has a scenario that I think would work pretty well. The aliens launch a probe that drops essentially a factory on a largish asteroid, then continues on to other star systems to do the same thing. This factor uses the asteroid as raw materials to build more factories, which it launches to Mars. These factors start duplicating themselves until there are enough of them. Then they start building and launching wave after wave of ships loaded with killer robots (probably small but not nanobot-size) to Earth. They simply overwhelm humans with huge numbers. The robots could be programmed to not kill anything besides humans. The reason this works is because the factories duplicate themselves exponentially (geometrically if you want to get technical). 1 factory becomes 2, 2 becomes 4, 4 becomes 8, etc. They could have one factory *per human* cranking out spaceships loaded with killer robots after just 33 replications. And since this is all happening on another planet, by the time humans can get around to building something to counterattack and it traveling the distance to Mars it will be too late. Even if humans launched a counterattack immediately it wouldn't arrive on Mars for at least 150 days. And that is not including the time it takes for humans to realize what is going on and actually build something capable of attacking Mars. [Answer] **Precision Lasers** If you want minimal collateral damage your best bet is lasers. Just put satellites in orbit around Earth with powerful telescopes and powerful lasers. It shouldn't be difficult for your aliens to construct these devices. We could do it now if we had the mind to. With a powerful enough laser, it would only take a few milliseconds to vaporize a sufficiently large cavity into the top of an unprotected human head. Let's say it takes 10 milliseconds to acquire a target, aim the laser, and deliver sufficient energy to kill a human. Reasonable in my opinion for an alien civilization capable of crossing the stars. This laser satellite could kill ~10 million people a day. Alone this laser would take a couple years to wipe out all of humanity. But of course, why would you just build one? Build 1000 of the satellites and anyone not covered will be dead in less than a day. The other advantage of using a laser weapon is it prevents humans from utilizing their nuclear weapons to muck up your new planet. Any doomsday scenario runs the risk of humans freaking out and nuking each other. Lesser intelligences, am I right? With lasers, every missile they launch at you or each other will be harmlessly knocked out of the sky within seconds. Now, what about those pesky humans who happened to be indoors when we started shooting or managed to make it to an underground bunker? Well, it depends on how patient your aliens are. Eventually, most of them will have to come outside for food or water and will be instantly acquired and eliminated. If your timetables are tighter because, hey, you've got other sentient species to eradicate, then those in more well-stocked facilities can be eliminated by *messier* means such as orbital bombardment or robotic ground troops. [Answer] Cure cancer. Well, not necessarily cancer... Create a cure of vaccine for a deadly disease, with a hidden twist: It introduces a genetic defect that causes viable male sperm to almost "Y" chromosome. Have a shell company produce, fund and distribute it to all children at birth. Someone will notice that no new females are being born - but, hopefully, by that point your shell-company have already applied the vaccine to most of the world's population. Just sit back and wait a hundred years or so, then mop-up the survivors. [Answer] I think the biggest problem with answering this question is that we are placing ourselves in the boots of a life form we know nothing about (i.e. maybe they only wear flipflops) What do they look like? Where do they live? What do they breathe? How many of them are there? What resources do they have? The answer depends a lot on the circumstance. That being said, here's a few ideas i came up with. **1** The aliens could use heavy weapons such as bombs or giant lasers or whatever they have available to destroy every large city (this is assuming they want the green stuff and not the manmade stuff) this would wipe out a large amount of the population by itself, although not 99.9% **2** Infiltrate corparations and add fatal components to popular items. Couple examples: Create a remotely activated parasite that would hide inside humans until it received the signal to active and destroy it's host. It could be implemented into anything edible such as coffee, apples, chicken, that sort of common thing. Add some sort of death chip to technology such as phones and electric egg beaters that, once activated, would kill the person using it. Create a range of popular apps that had a special feature, once activated, this feature would turn the user into a human-killing savage (kind of the plot of the first Kingsman movie) Unfortunately there would still be groups of people who farm and live away from technology so they would have to be exterminated via other means (like disease which others brought up, maybe animal carried?) Final Note: I wrote this on a phone so sorry for any errors. [Answer] I'm a bit curious as to why the aliens are only interested in exterminating humans? If they want to seize the real estate then they would likely discover that Earth isn't a very welcoming place, as a minimum most aliens would be suffering from severe allergic reactions to the proteins in Earth's ecosystem and it is highly unlikely the composition of the atmosphere, day/night cycles or gravity replicates what they have at home. If they are advanced and benevolent or indifferent, they might simply take over the rest of the Solar System and convert asteroids, comets, moons and so on into enclosed habitats which meet their needs exactly. Even building a Dyson Sphere while we helplessly looked on is quite possible. [![enter image description here](https://i.stack.imgur.com/OD75H.jpg)](https://i.stack.imgur.com/OD75H.jpg) *Let's see that Elon Musk guy top this!* For less than benevolent aliens, building a Dyson Sphere or even just a sunshade inside Earth's orbit (say the Earth-Sun [L1 point](https://infogalactic.com/info/Lagrangian_point#L1) and reducing the insolation of Earth will likely cause mass casualties as the ecosystem collapsed. Farming would be affected first, and billions of more casualties would be caused as people fought over the remaining stockpiles and stores of food and seeds. The collapse of society would rapidly cause the collapse of the industrial ecosystem, killing billions more as logistics stop, electricity fails and clean water, electrical energy and delivery of supplies of all types cease. The few feral humans remaining would likely be finished off if the insolation were throttled back even further causing an ice age..... [![enter image description here](https://i.stack.imgur.com/0bT2j.jpg)](https://i.stack.imgur.com/0bT2j.jpg) *Snowball Earth. Just cut off the sunlight for long enough....* If the technological approach was not to their taste, they could simply replace the biosphere with something more to their liking, much like the Martians in "[The War of the Worlds](https://infogalactic.com/info/The_War_of_the_Worlds)" introduced the Red Weed. If their ecosystem is millions or billions of years older, their plants and animals (or analogues, there may not be any direct equivalents) could simply outcompete the Earthly beings in every niche, which would rapidly kill off the plant and animal life *we* depend on to survive. [![enter image description here](https://i.stack.imgur.com/oR2kZ.jpg)](https://i.stack.imgur.com/oR2kZ.jpg) *H.G. Well's Martians engage in transforming the Earth* The short answer is that since the Terrestrial ecosystem is tightly integrated, any solution which "just" tries to kill humans is likely to be inefficient and very energy and labour intensive, while collapsing the ecosystem is likely to provide the aliens a clean slate to start with when occupying the Earth. [Answer] Looking over all these answers, I think the best route would be a virus or some other disease that targets humans specifically, and the aliens could use one which has been a problem for us for a long time: Influenza. They could make it far more virulent (pun intended,) enhance how it damages the body, then use drones to disperse it in key locations to maximize its spread. If the super-flu is potent enough, people could be dying within 24 hours of contracting it, as was the case with some of the victims of the Spanish Flu when it struck during WW I. Actually, that gives me an idea: The aliens could manipulate human nations into starting yet another world war, which means you'll have massive amounts of troops being moved around the globe but also being kept in camps and bases, where they're easier to infect. The scenario would be very much like the Spanish Flu outbreak that took the lives of *50 to 100 million people.* Alternatively, you could have them target a densely populated area of the world that also has a lot of people entering and leaving it on a daily basis. India would be one such region. It's packed with people, but it's also trade hub, so it wouldn't take long for people to carry the virus to other parts of the globe. Do this in multiple places simultaneously, and you've got a plague of epic proportions on your hands. People would be dying faster than any treatment could be devised. Those who managed to quarantine themselves could be dealt with by having one of the aliens pump the virus into the air filtration systems of the facilities their using. My point is, the aliens don't need to engineer some brand new disease to wipe out humanity, they just need to enhance one that already exists and let it do all the work for them. [Answer] well, they'll infiltrate our govt, make fake dossiers and get your neighbors to help kill us all off. For your info, they're already doing it. Research Targeted Individuals. [Answer] **Provide them with exactly what we want: Utopia** The worlds birth rate is already on a decline, it will peak at 11 billion end-of-century and decrease from there. This is mainly due to affluence and lifestyle factors trumping the desire to have children. The aliens are smart, they know this. The best way to eliminate the human race is to give them ultra-affluence, perhaps a simulator that is freely available, that gives everyone a perfect world. All you need to do is accelerate the decreasing birth rate. It's down to 1.6 per couple in some countries. Just take it down further, make people ultra-comfortable with *not having children, as they are tending to already*. This way also the humans will slowly dismantle their infrastructure, in fact may do so quite willingly, to prevent any other animals from dying. ]
[Question] [ A common trope in cyber punkish sci-fi is the ability to upload a human mind to some storage device or AI. This of course grants practical immortality but it is also the main hurdle for tropes like teleportation, cloning etc. So my question is: how close are we to being able to make restorable backups of a human brain? What scientific or engineering break throughs are required? For the sake of this question, the goal is: * To transfer the complete memories, feelings and "consciousness" (whatever that is) of a human being to an external storage device (electronic or biological) of some kind. * To be able to interact with the back up, directly or after a "restore" to another human body. * It should be impossible to tell original and back up apart without seeing their physical form. The question has been asked on [Quora](https://www.quora.com/How-close-are-we-to-creating-a-backup-of-the-data-contained-in-a-human-brain) but without any detailed answers. I'm tagging this "Science-based", but any hard-science answers are preferred. [Answer] We are still far away from being able to correctly interpret a neural system and to be able to simulate that on a computer of some kind. We have a kind of mixed situation about our understanding of brain (and nervous system in general) physiology; I will try to sketch what I understand of "State of the Art". * We have a fairly good understanding of neuron workings, down to molecular level, at least for local interactions. * We have several "models" that capture (at different levels of precision) neuron *functionality*, abstracting it completely from actual chemical processes powering it. These "models" are powerful and useful enough to be used in real-life A.I.s solving computationally "hard" problems (e.g.: weather forecasts). * We are not sure we have understood all implications of "systemic" neurotransmitters (the ones in the blood stream). * Systemic neurotransmitters seem to play a key role in "reward system" and thus on all network training and memorization. * We have a general map of connections between neurons both in brain and in Spinal chord. * We have no *detailed* connection map. * There is still no consensus if current neuron *models* actually contain enough information to faithfully replicate a Natural Neuron Network functionality in a Simulated Neuron Network. * We have little to no understanding of process leading to formation of new synapses (neuron connections). * We have little to no understanding of processes leading to modification of synapses. * The above two points mean we are really far from having a sensible breakthrough on learning and memorization processes. * A detailed mapping of neuron interconnection is impossible right now, but is thinkable in a relatively near future. * Compute a map of "weight" connection for each neuron is a problem several orders of magnitude more complex, but still theoretically doable. * As said there is no consensus about if and, eventually, how much these parameters unequivocally characterize the whole network. * Assuming all this data actually define enough the brain there is the problem to fully simulate this NNN with a suitable SNN (computationally intractable, to date, essentially due to the high degree of parallelism needed). * If and when the above problems are solved it's possible to have a simulated conscience responding (given the necessary "peripherals") "as if" the original human was still alive. A few problems would remain: + as said there's still not consensus if the model I'm outlining captures enough of neuron complexity to replicate faithfully behavior. + these models completely ignore "systemic" influences. + these models do not include any part of some proposed (and undemonstrated) "local" interneuron "resonances". + in any case it would be a conscience "frozen", with no way to learn anything "long term" (short term memories would be possible). * There are studies on how to model neuron interaction at a higher level, but AFAIK they are not applicable for "backup" purposes. I see *no* way to restore any kind of "backup" unto a biologic brain, in *any* foreseeable future, as: * We have no understanding of how to grow neurons with specific connection pattern (neurons grow new connections in the learning process, reaching several *hundred thousand* connection for a single neuron) * We have very small chance to "restore" behavior of even a *single* neuron because signal sensitivity is encoded in membrane artifacts which will be very hard to duplicate. * We need to do the above on almost a *hundred billions* neurons (not counting sympathetic system, spinal chord and the myriad nerve ganglia we have almost anywhere; *note: recent studies indicate these are **not** irrelevant to our behavior*). * Some of the "global" states of the brain are controlled by "systemic" neurotransmitters floating in the blood stream. At least some of these are generated by systems very far from the brain (cardiac ganglia, adrenal glands, intestine, etc.). [Answer] We are really far, far away. First of all, we still don't know how memories, feeling and consciousness are coded in our brain. We have some ideas on which brain areas are devoted to certain tasks (sort of black box model), but we still lack the finer detail. If we make the (somehow poor) analogy with a computer, we know which is the RAM, the ROM and which the GPU, but we have no clue on how data are processed and stored there. Now, imagine how ridiculous would somebody appear approaching a hard disk with just paper and pen to copy its content, and you have a hint of our standpoint when it comes to "copying brains". The first breakthrough would then be to understand this fine level detail. By knowing how the information is coded, we can read it (continuing with the computer analogy, once we know that bits are coded with a magnetic field on the substrate, we can arrange a magnetic head to read it). Once this is known, we can then move on to try to replicate it. Once we are able to replicate it, copying and pasting is possible. [Answer] Saying "very far away" may be an understatement. First of all, we do not have the faintest idea of how the brain works at all, nor a good way of even looking at it. This profound non-understanding coupled with very modest means to even look at what's going on has lead to ill-advised beliefs such as we're only using 10% of our brain. There's EEG, which is basically a couple of wiggly lines in which scientists try to find patterns, but if you're being honest it's close to reading tea leaves. The problem is that what the EEG shows is a summation of interfering microscopic impulses along a multitude of vectors, under the (probably wrong) assumption/simplification that cranial structures and/or skin conductivity go exactly the way you think and do not influence the outcome. Put differently, you're looking at some pretty patterns, but there's no way you can truthfully make too much of it in a sense of "read mind" or even "copy a personality". But even assuming you could read someone's mind that way, this would likely still not let you extract knowledge that isn't being accessed or copy a personality from those electric impulses. There's the UCSD experiment where probands (although the researchers were in my opinion cheating because all they really measured was the brain's response to a flicker pattern that probands looked at!) managed to "dial" numbers on a cell phone by means of thought patterns. Well, awesome. The brain reacts to external stimuli, that's big news. Now tell me how to upload your mind to your cellphone. And there's MRI, which gives even prettier patterns than EEG, in color and in 3D. You can show that certain areas of the brain light up when certain things are done or when certain external stimuli appear. While this is impressive, it's approximately the same thing Mengele did 70 years earlier, only less invasive, and at slightly higher resolution. From "we see these areas light up" to "copy a personality" it's approximately like having discovered that things that you drop fall to the ground and a manned mission to Mars. We do not know exactly *how* the brain stores (or processes) information. Yes, we do have some educated guesses, but we don't really know exactly. When looking at not only what a simple honey bee is capable of *remembering*, but also how capable it is at path planning and rather non-trivial mechanical tasks, I'm stunned how the hell nature manages to fit all that into a brain the size of a needle pin. How large is *your* brain again? Good luck decoding that. We do not even know how much information a human brain can store, but we *do know* that the amount is huge, and we know that information is stored in a non-obvious way which one could consider a kind of "interlinked lossy compression with forward and backward error correction". Something like that. Memories are not just data, they are data that has been filtered, weighted and validated, and connected to other, sometimes unrelated data in a non-obvious way, with massive holes that are filled from other data, or sometimes interpolated with what seems plausible to the brain, and with no way of telling a difference (guess why witnesses are such a pain in the ass). So far, we cannot even remotely guess how this works at all. We can only tell it must be something the like from observing what people remember (and sometimes what they *think* they remember). Some personality-defining memories/abilities (let's say playing an instrument) are in addition supported by dedicated hardware (if you want to call the cerebellum that). Which, of course, you would need to somehow copy too. We don't know whether *personality* has anything to do with stored information either, or where personality comes from, for that matter. Is it defined by your experience? Genetic? Given by God? Hardwired by your dendrites? Stored chemically? We have no idea. We can only tell from observation, with reasonable certitude, that it's *probably not* one of the previously mentioned things alone. Experiments that might give an answer would take decades and would be highly unethical to the point of being forbidding (e.g. raise clones in different environments, observe them for 20-25 years, then cut their brains to slices). If we knew all of the above, we still wouldn't know how to map all of this to a digital format that a computer can store, let alone build a computer large enough to do the job, or how to "transfer back" the mind, once copied and stored. While it might, in principle, be feasible one day to copy the "data" from the human via some "scan thingie", the brain simply isn't built to receive a new mind like this. There's no "input" plug of sorts. [Answer] Like others have said already, this is still in the not-forseable future. The main reason is very simple: We have no clue how consciousness actually works. Science has made a lot of progress explaining the most basic building blocks of nerves and brains. We have also accumulated a lot of knowledge of finer details, but here already our understand of **how** this actually happens is beginning to be vague. For example, object recognition and object persistence in visual perception. We know a lot about it, and another lot is under active research because we haven't figured it out yet. And that's a low-level building block of the entire visual system. And as any IT person knows, backup is just one half of the process, restore is the other. AFAIK, nobody has the slightest clue towards how to manufacture a brain, or even a simulation of a brain sufficiently advanced to allow human consciousness to run. We are so far away from this that any estimate of when we'll be there is pure speculation. [Answer] First, I'd like to mention that exactly this mechanism is used in *Commonwealth Saga* by P.Hamilton. I suggest reading through these books if you'd enjoy seeing how such technology affects society in everyday life. Probably there are dozens of other examples, though. Now, regarding the question: we are far away from such tech. 1. We don't know how exactly our brain works. Currently, we're able to create neural networks with [150+ billions](https://spectrum.ieee.org/tech-talk/computing/software/biggest-neural-network-ever-pushes-ai-deep-learning) of neurons, and yet we're not even close to simulating human brain. As AlexP pointed out below, it's not quite correct to compare artificial neuronetworks (ANN) with human brain because they serve different purpose. But history of such networks begins with modelling human neurons, so let's at least say we *tried* to simulate the brain. 2. We don't know how exactly the information is *stored* inside our brain. In simple words, we think that patterns of active neural chains form our memories, but I haven't heard about anyone ever replicating "memory' as it is. There is also a [holographic theory](https://en.wikipedia.org/wiki/Holonomic_brain_theory): we assume that each piece of information is spread all over the brain. If we remove some part of it, we can still restore the entire memory from the rest of the brain at the cost of "resolution". Just like with holographic pictures. Generic information like reflexes might be stored this way. I mean, there are different views on how it works and no one ever claimed their approach to be 100% correct. 3. Even *restoring* memory is almost impossible in case when it's not a psychological factor (like intuitive defence mechanism). [Here](http://www.dailymail.co.uk/sciencetech/article-3495502/What-memory-LOOKS-like-Scientists-restore-lost-memories-flicking-light-switch-brain.html) we see scientists restore part of the memory for mice, but as far as I understand it, it doesn't last long after procedure is over. So technically, if we want to restore memory via medical intervention, we're in trouble. So, in conclusion, we are not ready to introduce separate memory storage compatible with human brain. Because memories are not binary, I suspect we need to simulate neurons to properly treat them outside of our heads. Of course, that is my personal opinion. [Answer] It is impossible to know how far we are away from eternal consciousness. We are far enough away from being able to do this that we don't even know enough to figure out how far we are away! Most agree it wont happen soon (i.e. not in the next 25 years), but nobody can say whether we're 100 years away or 100,000,000 years away. We don't even have a solid scientific definition of consciousness, though there are [some interesting ones](https://en.wikipedia.org/wiki/Integrated_information_theory) being floated which rely on information theory. It's not even clear whether or not the idea of "preserving consciousness" is meaningful without also preserving the entire environment (i.e. copying the universe). Also unclear is whether one can copy a consciousness without also copying the death-creating features that are present in our cells. It may not be possible to unlink what we call "consciousness" from the natural cycle of life and death. The thing that we may unlink from this cycle may not even meet our current definitions for consciousness. I highly recommend reading about the philosophical problem: [The Ship of Theseus](https://en.wikipedia.org/wiki/Ship_of_Theseus). It is a thought experiment regarding identity which dates at least 2000 years back, and there is still not a solid consensus as to how to resolve this problem. We would *certainly* need to have solved this multi-milinia old problem before we could accomplish what you seek. [Answer] One possibility that I haven't seen considered in the existing answers: rather than just "far away", it might be fundamentally impossible. First, a short anecdote: some time in the 90s I ran a primitive markov bot (perhaps even too primitive to be called a markov bot since it didn't really even have weighted probabilities) on IRC. For readers not familiar with the concept, the general idea was that it would build a corpus of short chains of words from things other people chatting wrote, and randomly assemble them into sometimes-meaningful sentences. Anyway, at initial setup most of the output was nonsense, after a few weeks it was producing lots of amusement, and after a few more weeks the output was again nonsense. The problem was that both presence of "useful associations", and absence of "too many associations", was necessary to get something other than garbage out. So, back to human or human-like consciousness: it's possible that the entire neural model of our consciousness has fundamental limits on "how much experience" it can accumulate without becoming overloaded and starting to produce less-useful and eventually all-garbage output. If there is such a limit, it might or might not scale with the size of the neural network. This kind of limit seems plausible in terms of how our experience of consciousness changes with age or with accumulation of more and more fields of knowledge, gradually transforming from vivid memories of specific things and events to more of a "digest memory". What happens if you keep throwing more experience into that without bound? Does it break down entirely into dementia? Is dementia entirely a matter of physical/physiological faults in the nervous system, or also partly a computational state? Can a human (or augmented/digitized) mind progress successfully to further and further states of being able to work with thousands or millions of years of experiences? Fortunately, these are all amazingly fun questions from a scifi writing/worldbuilding perspective, but if anything the fact that they're open supports the view that we're at best far, far away from achieving what OP asked about. [Answer] ## Yes, it is possible but the person can not be put into a computer directly. In order for eternal life to exist we first must invent sentient Artificial Intelligence. Once sentient A.I is in existence we may be able to programme personality traits into it. Once we have the same personality of whoever wants to be posthumanised we then have to collect their memories. This is simple as we could just have the person in question give their life story in as much detail as possible and all of the knowledge they have acquired. So once we have an A.I programmed with their personality we programme their memories into it. Once the A.I is programmed, and the customer is satisfied, we must then kill the customer. This is to prevent any problems that would be caused by there being two of the same personality. an Android is then built that looks exactly like the person, their digital clone is put into it, and then we send the clone out. Then it lives it's life as the original. Yes I do know that this idea is not the actual person but it is the closest way I can think of that is realistic. The problem with "cloud saving" memories is that the brain and computers are radically different to each other. If you would like to research this topic further this concept is called whole brain emulation. [Answer] **TL;DR -- I can believe the upload might be possible in the far future, but I don't think download is feasible** This is difficult, difficult. Let's say our scanning technology is awesome; we can map every neuron-to-neuron connection and (if necessary) the current charge-state of each. Cool, we upload Jim to our computer. Oh dear ... we forgot the epicellular data -- the brain is awash in hormones and chemicals of various sorts. Okay, with v2 we got this measured and modeled too. So now we have a copy of ol' Jimbo. Oh dear ... we forgot that there is a steady stream of *input* coming into the brain from all the nerves. Computer-Jim quickly goes insane from total sensory deprivation. Time for v3. Okay, now we're cool. Jim and Computer-Jim amuse themselves with endless games of "Jinx! You owe me a soda!" Till finally Computer-Jim sobers a bit and says, "So when they restore back into my head, will it hurt?" Jim goes, "No, **I'm** the one with the body, dummy!" CJ: "Nuh-uh." J: "Yeah-huh" CJ and J together: "Jerk. ... Jinx! You owe me a soda!" Here's where it gets **really** hard. The transfer is not just information; we have to physically wind the neurons into place, adjust the chemical soup of the cerebrospinal fluid, and make sure all the right neurons are firing. Assuming you've found a volunteer body, or a ... "volunteer" body, this is a tough row to hoe. But cool. Restored-Jim *immediately* goes into convulsions. Oh dear ... could it be that the lower levels of his brain aren't interfacing properly with the signals coming out of the spinal cord? Restored-Jim's body has different muscle mass. A different amount of skin. Might be opposite sex. The signals coming out from his cerebellum are going to the wrong muscles (including the heart, woops) or using the wrong amount of force. There might not even *be* a good mapping of spinal-cord nerves to cerebellum nerves. But let's say we overcome this somehow. Restored-Jim feels *awful* in his new body. Nothing works right. He doesn't fit his own self-image. "Didn't I used to be caucasian? Is Turkish really *me*? Do you have something in an early Aztec physique?" While watching this, Computer-Jim -- we didn't turn him off, right? -- is saying "This is no fair! Why did you send *him* to the new body and not *me*?" Doc: "Uh..." Computer-Doc: "Jeez you idiot! Why did I let you have the body this week anyway?" ]
[Question] [ **Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/59856/edit). Closed 7 years ago. [Improve this question](/posts/59856/edit) Say that at some point of history in the far future, time travel becomes possible. That means that from then on anybody could travel in time. If that is possible, doesn't this mean that our present, past and future would be filled with time travelers over the years? For example say that a time traveler from 2100 comes to 2016. We now have 1 time traveler apparition in 2016. In 2106 somebody else has the idea to visit 2016 so we would have 2 time traveller apparitions in 2016. Over the years all the people who will ever have the idea to visit 2016 will be added to the apparitions. Won't that create a 2016 (or any other year) filled with time traveler apparitions that would be too hard to be hidden? What I am asking is: is any time travel (suppose that both forward and back in time is invented) possible, without making the planet a, huge and obvious to the people of the past, 'tourist attraction' or operation field for swarms of time travellers who will ever want to be there for any reason? [Answer] This is a classic philosophical question. You can probably find all sorts of interesting discussion of it around the internet, so I'll just talk about my view. I'll largely ignore travel into the future, because travelling into the future is something we already know how to do - just build a spaceship, get on board and accelerate as close to the speed of light as you can manage and let time dilation do the work. Building such a spaceship is left as an exercise for the reader. Certainly, the lack of time travellers from the future has been seen as an indication that time travel will never be invented. Douglas Adams wrote in one of the *Hitchhiker's Guide To The Galaxy* books or radio episodes (or both), something to the effect of "time travel, by its very nature, is invented in all eras simultaneously". So either there is time travel, or there isn't, but you can't have a point where time travel is invented because once it's been invented people can travel back in time and someone in the past is going to figure it out and it just carries on from there. That only works, though, if you look at one particular model of how time travel works. In Adams' work, time travel technology allows the user to move freely backwards and forwards in time, from the beginning of the universe (where they built a restaurant called the Big Bang Burger Chef), to the end of the universe (where you can dine at Milliway's, the Restaurant at the End of the Universe). But it doesn't necessarily have to work like that. In the television series *Quantum Leap*, a time travel device is invented which only allows the user to travel into the past within their own lifetime. Mutation of history is entirely possible in the show's model, and indeed that's primarily what the main character engages in for largely altruistic reasons. In addition, the "leaper" actually swaps places with a targeted person in the past, taking on their appearance during the leap and basically impersonating them. So in this model, not only is time travel limited to a human lifespan before its invention, time travellers are effectively undetectable (provided they impersonate people sufficiently well). Obviously this is a storytelling device to give the show interesting scenarios each week (they had a lot of fun sending Sam into people with no legs, pregnant women etc) but it does provide an answer to your question. There are other such limitations. Rather than the lifetime of the traveller, the machine may only be able to enable time travel within a time period where the machine itself exists - so you can never travel back to before the machine was invented (or forward to after it was destroyed, if it allows you to travel forward). This is shown in several things, but the film *Primer* stands out as an example of this for me. In that film, the time machine has to be built, turned on and left. Later on, you can get inside it and wait the same amount of time before getting out, and you'll emerge just after it was built (it only travels backwards at the same speed you usually go forward, so travelling back two months takes two months of sitting in an airtight box). So in that world, again, once the machine is invented you might see time travellers everywhere, but never beforehand, and because you travel back at 1 second per second you're severely limited by both your lifespan, your ability to cope with the experience of the journey, and the availability of a machine which someone else isn't already using and which retains power and integrity for the necessary time. There are also the numerous possibilities of multiple timelines, such as the idea that travelling backwards in time immediately makes a new timeline which isn't the same as the one you originally came from, and that this limits the appearance of time travellers somewhat because they don't all go back to the same one and neither do they all come from the same future timeline. Of course, there is also the possibility that there is a fair bit of time travel activity but that various people try to cover it up, regulate it, police it and possibly utilise more time travel to prevent the first time travel incident from ever occurring. This model is much in evidence in the *Star Trek: Department of Temporal Investigations* books, where a variety of "uptime" agencies are seen intervening to mitigate, cover up or outright erase from history various time travel incidents. However, in that setting many people are aware that time travel is possible and that it happens sometimes. They're just usually sworn to secrecy if it happens, or their memories are altered, or they end up dead. [Answer] Depends on your time travel model - if you have a branching model, where each time hop creates a new branch, then there isn't an issue. Each branch has a fixed number of time hops, so doesn't change - if anyone extra hops back, they end up in a different, new branch, so the original branch isn't affected, and the new branch has always had one more hop than the original. So you can have a branch with no hops, and branches with lots of hops - but from the point of view of people in that branch, it's always been the same; you don't see history changing. If you have a single timeline model, I like Larry Niven's solution: If time travel is ever invented, someone sometime will use it to meddle, changing the timeline. This will keep happening as long as time travel exists - until someone meddles so that time travel is never invented, which is the only stable state. [Answer] There is a time travel model where the time travellers can be sent back into time to a fixed time. Basically, it is a wormhole in time domain. This model do not allow wormhole to be opened to the past, but to the future. Wormhole can be traversed in either direction or from future to past. With this model and ability to reach lightspeed (should be trivial by now) allows someone to reach any time zone between his time zone to the creation of time travel. **This means, there will be no time travellers until the invention of time travel.** [Answer] Time is big, and the future is much larger than the past. If took the current world population and sent each person to a random point in [time of stars](https://en.wikipedia.org/wiki/Future_of_an_expanding_universe#Stelliferous_Era) and they then lived for a century, for less than 1% of that time would there be a time traveller alive in the universe. So you *might* get everyone wanting to visit 2016, but they may be a trillion other years to visit. [Answer] First, for there to be a lot of time travellers, time travel would not only have to possible, it would have to be (relatively) cheap. As a parallel, space travel is certainly possible, but space is not (currently) filled with space travelling humans. (Google gives the largest number as 13: <http://www.space.com/6503-population-space-historic-high-13.html> ) Second, having a large number of time travellers implicitly assumes a long future. Suppose time travel is invented in 2100, but due to global warming humans (at least those who haven't escaped into the past :-)) go extinct by 2200. Then a relative handful of time travellers are spread over hundreds of millions of years of habitable past. PS: A scenario where we're all (mostly) descended from time travellers. Time travel is invented just before the global extinction, the developers and their friends escape to Europe ca. 50K years ago, and so displace the Neandertal population... [Answer] You may want to look at [this paper](https://arxiv.org/abs/quant-ph/0506027). Quote from the Conclusion of this paper: "According to our model, if you travel into the past quantum mechanically, you would only see those alternatives consistent with the world you left behind you. In other words, while you are aware of the past, you cannot change it. No matter how unlikely the events are that could have led to your present circumstances, once they have actually occurred, they cannot be changed. Your trip would set up resonances that are consistent with the future that has already unfolded." This does not necessarily answer your question directly, but from it follows that maybe there **will be or has been or will have been** a year in which there is a huge influx of time travellers, which will cause future time travellers to know about this historic event, **making them interested in seeing what was up back then.** On the other hand, it's not possible for these time travellers to slowly accumulate "over the iterations" so to say, because **they will always have been there**. [Answer] A very possible reason we haven't seen any time travelers yet, is a time machine can only "bring back" and so you can't travel to before the machine was invented. The movie Primer used this, and this style of time travel can be a bit hard to wrap your head around... ]
[Question] [ So, I have a character who has the ability to alter the velocity of any liquid water less than three inches away from her body, accelerating it in any direction she likes. With concentration and practice, she can make different parts of her body push the water around them in different directions from each other, and if she makes the water flow across her body (such as from one outstretched arm to the other), she can give it more time to accelerate before leaving her power's field of influence. One thing I had planned for her to use this power for is to basically propel her through the water to allow her to swim really fast, basically using the water she "waterbends" as jet thrusters. The problem, I just recently realized, is that she isn't actually pushing on the water in any way. She's just magically accelerating it, so there isn't any equal and opposite reaction pushing her in the opposite direction. So that makes me think that perhaps she can't actually swim faster by propelling the water around her in the opposite direction she wants to go, and because of that, I'm starting to think her power would actually be useless for trying to swim faster at all. **Am I wrong? Is there any way this character could use her water-accelerating power to propel herself through the water?** [Answer] She just has to direct all the water around her to go in the direction she wants to go. She'll be taken along with it automatically; the water behind her pushes her and the water in front creates a lower pressure region which pulls her. [Answer] The important thing is whether the magical acceleration is *relative to herself* or *relative to a rest frame*. In the second case, she can encase herself in a "water bubble" and accelerate the bubble however she wants. If the water needn't be in contact with a larger body of water, then she can shape a large freesbee-shaped flying saucer and zip around on it. This sounds a bit too easy to me, though. In the first case, this won't work, but we can use three different methods. One: she submerges, and magically accelerates the water in front of her so that it parts, going backward, at the same time forcing the water all around to *stay still*. This creates a suction that will move her forward. New water will flow in the acceleration zone, and be expelled backwards. She is essentially "paddling" with a large tube-shaped invisible magic oar. If she can continuously shift the magic from the water being expelled backwards to the inrushing water, and keep the outer water "funnel" stable, then she can create a magical hydroturbine with a maximum theoretical speed of Mach 4.4. Two: she accelerates several pencil-thin jets of water inward and in front of her. The water doesn't give her momentum, *but it immediately mixes with the remaining water all around*, creating a current. She can swim in the current. Three: she creates a magical water torus with herself in the center, with the water rushing in from the direction she wants to go. The water in the torus rotates like this [![enter image description here](https://i.stack.imgur.com/9pU9W.gif)](https://i.stack.imgur.com/9pU9W.gif) This magic "smoke ring" in the water has a turbulent surface on the inner border. This will force *other*, normal, non-magicked water to be sucked in and expelled, as if from an impeller, which again will allow her to flow forward at a significant speed (bringing the magical torus along with her, and experiencing no drag from it *because magic* - the same lack of action/reaction that prevents her from exploiting a water jet now plays in favour). This is possibly easier to do, concentration-wise, because the impeller can be made of the same water continuously rotating (there is no need to continuously re-magick new water). It is not too different from creating a pair of invisible propellers out of magicked water and having them rotate. The whole volume in which the torus and the swimmer are immersed can be imagined as a "physically consistent and law-abiding black box", wherein water is sucked from the front and ejected at speed from behind. Therefore, the whole volume is propelled forward. A similar effect, requiring more control, would be to create a zero-acceleration ovoidal shell (so, a shell the water cannot go through - made of water and magick instead of metal, but still a submarine shell). At the front and at the back there will be two "holes" in the shell, and water would be accelerated inside the first and outside the other, creating a [MHD](https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive) (MagickalHydroDynamic) drive setup. [![enter image description here](https://i.stack.imgur.com/N2g1l.png)](https://i.stack.imgur.com/N2g1l.png) [Answer] Forget about swimming really fast. Humans float in water[citation needed]. If she is enveloped in a mass of water that covers all of her body (maybe except the nose and mouth, so that she can breath), she could accelerate that water upwards. When the acceleration is greater than approximately 9.8m/s2 (1G), she goes up. When the acceleration is exactly that, she hovers in air. When she accelerates in any other direction, she **FLIES** that way. If she tries to swim in a body of water really fast, she has the problem that she will eventually [cavitate](https://en.wikipedia.org/wiki/Cavitation). There is no such limitation in air. [Answer] **Accelerate into herself** She can direct the water and accelerate it. If you accelerate it against your body, it'll give direction. Most likely you'll push sideways, partly into the direction you want to go and partly into the body, as not all surfaces of her are pointing into the direction she wants to go. This way she will definitely accelerate herself significantly. The water is pushing her, not her pushing the water. [Answer] So fun fact of water: It has the unusual chemical property at being at it's densest in it's liquid state rather than it's solid state (because solid water forms crystalline structures) so it's a good substance to use to propel objects through water. Things like Jet skis, will typically use a jet of water to propel the craft forward, and even then, animals such as Octopi (Octopodes, Octopuses, whatever) and squids use jet propulsion to swim. The motion is because, in part, water is being displaced and nature abhors a vacuum, meaning water is going to immediately rush in and fill the gap of the displaced water, which will create push against the person. There's an entire branch of physics that is devoted to the study of how fluids (liquids and gasses) interact and move called Fluid Dynamics. Though one thing you aren't considering is that unless your magician is not of terrestrial animal nature, she is about 70% liquid water by body weight. Why not just throw her water weight around and let it pull her non-water weight (the carbon, the calcium, the nitrogen, and oxygen) along for the ride? [Answer] # **Actually, Yes** So a big issue with swimming in water that is not present in air is friction and drag. Because water is a liquid, rather than a gas (not to mention much, much denser), the molecules still have intermittent bonds to one another and this makes it a lot harder to force one's way through. This is made worse by the fact that because of how fluid dynamics work, flow is often at its slowest nearest to the object in question (laminar flow). This makes swimming fast very energetically costly, and indeed, at very high speeds [this can cause serious damage due to cavitation bubbles](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2607394/). Living high-speed swimmers such as dolphins, marlin, makos, and tuna sometimes show tissue damage from cavitation bubbles, and it's though that the maximum speed seen in living ocean animals today is about as fast as a biological organism can get in the water...which is notably much slower than the speeds that the fastest land animals or birds can reach. The fastest reliably recorded marine animal is only about 75 kph. In fact, submarines and boats, which are made of much tougher materials like steel and titanium, often show damage from caviation when made to go very fast. *However*, one way around this is to create a bubble of air surrounding the object, which means the object is technically travelling in air rather than water, and hence can travel much faster without significant drag or friction and avoids caviatation damage. The [denticles of mako sharks do this to reduce drag and increase speed](https://royalsocietypublishing.org/doi/10.1098/rsta.2010.0201), and [similar ideas have been proposed to increase the speed of torpedos](https://en.wikipedia.org/wiki/Supercavitation). So, for your character that can telekinetically control water to some degree, they can compel the water to allow a small bubble of air around their body to reduce friction and create a supercavitation bubble. This is not too dissimilar from proposals for an Alcubierre Drive for faster-than-light travel, but in water instead of in space. Indeed, this has precedent in the sharkskin-inspired suits that Speedo made, which increased swimming speed by such a huge margin they got themselves *banned* from the Olympics. This would allow them to swim much, much faster than an ordinary human. [Answer] @ths answer is one option basically magical water bubble which moves Another option is to attract water to surface of the body, with different force/pressure creating buoyancy force in direction of let's say legs to head, and pushing in oposite directions water in front, to reduce drag. * buoyancy is created exactly the same way as real one, there should be a picture of sitution for a better explanation, buuut no budget for that, lol In frame reference of ones body it means one(the same) configuration of forces/mental excercise is applied, and you steer more or less like usual diver/superman style. Buoyancy force will not nessarly be that drastic, but pushing water sidevise in front of allow to have pretty much no resistance, so acceleration will be not fast(idk 1 m/ss ?) but top speed can be okayish, depends on lmitation of force, apllied to remove water in front. If there is watershield around body, basically hold some surface layer more or less stationary around the body, then pressure gradient, force applied to the surface of the layer can be higher and it means top speed maneuvarability and acceleration will be higher. [Answer] Imagine that she is wearing a sort of backpack full of water, and the water is pushed out of the backpack, the reaction will be transferred to her body. Before she starts pushing out the water she is at rest, so her momentum is 0. Once the water is moving out and away from her body, to conserve momentum she will need to be moving in the opposite direction. ]
[Question] [ The background is simple. An emperor wants to create a more splendid colosseum than the one they have but tasks the engineers making it with the following: * **The court or field is about a 100 by 65 meters.** * **The underground should be extensive to support the needs of the sports.** Ahm. Like staging mock sea battles. You know. Basic stuff * **The stadium should protect the viewers from the elements as well as it can be made while also providing enough light so that people can see, and be well ventilated** * **Viewer comfort and seeing is important**. Important point as they already have another stadium. This one is made to be better but smaller. People should have a better experience here. * **Heavily decorated and made to be fancy and a sign of wealth and power**. I'm not asking for decoration here but just saying that it is something to be kept in mind. This is not a modern stadium. * **Lastly it should feel intimate, somehow, people there should feels that the athletes are really close. Athletes also feel that.** This is something I took from watching football, soccer for our American friends, as many teams can tell you that certain stadium are a lot harder to play in with the home supports acting as a huge factor in the home team favor. * As durable and resilient as possible. * **Edit**: The capacity should be as many as possible but only as long as it does not contradict the other point. If dropping 10000 seats to the design satisfy the other requirements then sure. If adding them does not hurt then also sure. Tech is not above 16 century tech. Resources are practically unlimited in time, materials, manpower, or anything else. **So. What are they making? The overall shape? The capacity? Or whatever else you guys think is important to create that beast** I hope it can be done. But if not then what is not working? ## Extra fluff The Colosseum or Flavian Amphitheatre could hold as many as 80000. Modern stadiums can even go as far as 110000 people for something like Sardar Patel Stadium. And the 100000 range is not an issue. My problem with some of the largest stadiums that they feel cold as well as too modern and both contradict this particular colosseum. For examples Beaver Stadium or Ohio Stadium are huge but fall into that category. I much prefer something a lot more smaller and intense like Anfield stadium or a smaller version of San Siro. Even the original colosseum does not capture the intimacy and magnificent that I'm looking for here. That's why I'm asking and did not just get a number from a stadium I like and picked an overall shape and size and boom we have the new colosseum. [Answer] # The design of the arena reflects the use! ## [Amphitheater](https://en.wikipedia.org/wiki/Amphitheatre) What we call [Colosseum](https://en.wikipedia.org/wiki/Colosseum) today was once the Flavian Amphitheatre. The ruins we know today reflect in some art the original, but had been used as a quarry and stripped of most decoration. Researchers estimate between 50 and 80 thousand visitors, depending on one crucial fact: Do we count the additional 30000 seats on the steep wooden ranks that were added during use or not? In its original design, it featured fabric roofing for a sizeable portion of the visitors. Its design was ingenious to be made mainly from arches, speeding up construction, reducing costs by magnitudes, and still allowing *every* spectator a good view of the spectacle! Besides the amenities provided by vendors, it was connected to the roman canalization and even was flooded to show off [Naumachia](https://en.wikipedia.org/wiki/Naumachia) in it. [![enter image description here](https://i.stack.imgur.com/ixAU0.png)](https://i.stack.imgur.com/ixAU0.png) Nowadays we still use a building of this design in [Arles: it hosts bullfights](https://en.wikipedia.org/wiki/Arles_Amphitheatre) but it also was modified in medieval times, making it appear to miss arches. The [Pula Arena](https://en.wikipedia.org/wiki/Pula_Arena) was restored to the almost original design in the outer walls while the interior was partially remodeled for theatre use. The former Arena measures 67.95 by 41.65 m (222.9 by 136.6 ft). In its most simple design, the Amphitheater is pretty much a solid dam of dirt with the seating on it, and some access tunnels into the arena for access and at the same time drain it of water during rain. One such example is in [Pompejii](https://en.wikipedia.org/wiki/Amphitheatre_of_Pompeii). This building is known for its near-perfect riot control design and the good sanitary design as it shared its public toilets with the [neighboring wrestling school](https://en.wikipedia.org/wiki/Palaestra)! ## [Circus](https://en.wikipedia.org/wiki/Circus_(building)) Just some miles over was the even larger [Circus Maximus](https://en.wikipedia.org/wiki/Circus_Maximus), offering seating for 150 thousand people on a long, oblong track. Designed for chariot and horse racing, it provided a much better overview over the whole track than any modern racing arena. In total, the building occupied an area of 621 m (2,037 ft) by 118 m (387 ft). The orientation is off of the East-West and North-South axis, offering as little sun directly into the eye as possible during the races, but the playing of the building did result in rainwater runoff into the flat side of the arena till a proper runoff redirection allowed races even in the worst weather. In contrast to the Flavian Amphitheatre, no source speaks of sun roofing erected here. [![enter image description here](https://i.stack.imgur.com/kef2b.jpg)](https://i.stack.imgur.com/kef2b.jpg) Note that the eastern Romans had *extreme* intimate race events on the hippodrome constructed to house 100000 people: People were so sworn in to "their" team (or rather: Demes - Blue and Green), that they regularly battled each other on the streets, wore their team colors and these sports teams were almost political parties! By the way, I strongly suggest [Extra Credits Justinian & Theodora](https://www.youtube.com/watch?v=H_2E0RxVHH4&list=PLhyKYa0YJ_5Cfgs7L6XFvcQE_TpyyYiEI) series here, which does shed some light on the phenomenon of the races in eastern Rome in the first part's later half. ## Gymnasium & [Palestra](https://edition-topoi.org/dEbookViewer/bsa_058_07.pdf) For athletic competitions and footraces, the buildings were usually smaller but similar in design. Events that drew only small amounts of visitors would often be held directly in the training grounds. For example, the aforementioned [Wrestling school in Pompeji](https://en.wikipedia.org/wiki/Palaestra) was also the place for smaller or tryout wrestling matches that wouldn't be held in the larger theater. The [Palestra in Olympia](https://en.wikipedia.org/wiki/Palaestra_at_Olympia) featured slightly raised ranks around a square arena in the center, the outer area of which was covered by arcades. [Delphi](https://en.wikipedia.org/wiki/Palaestra_at_Delphi) featured a similar design. Spectators did have to contend for viewing space here. Similarly, the [Gymnasia](https://en.wikipedia.org/wiki/Gymnasium_(ancient_Greece)) and Stadia for athletics often were used for the competitions themselves, allowing spectators to watch from the shaded arcades - or in [Olympia](https://en.wikipedia.org/wiki/Stadium_at_Olympia) from earthen mounds surrounding the leveled tracks that would house seating during the festival. The only other permanent structure in the Olympia stadium was the judge tribune, the access ditch, and the starting line. The Gymnasium in Olympia, which is a separate place from the Stadium, did feature several terraces of stone for spectators, while [in Delphi](https://en.wikipedia.org/wiki/Gymnasium_at_Delphi) the access road to the temple above the place had a retaining wall that provided an extra rank for visitors to watch from above while others huddled at the sidelines ## [Theater](https://en.wikipedia.org/wiki/Roman_theatre_(structure)) Designed for the consumption of plays and borrowing from the greek design, they are half-circular in design. In contrast to the greek design, the upper rows in the roman design are usually steeper, allowing more spectators. # Best intimate design? To achieve the wanted intimacy, I would look for the designs in Olympia and rigorously stagger competitions and distribute them over a huge complex of arenas: there are places for wrestling and such for runners, there is a horse racing track at the side (that takes space) and maybe a nearby river or lake allows for swimming competitions to be watched from the banks. Since each arena only features a restricted number of watchers, people go and watch the sport they are most interested in. In an odd suggestion, it might be best to use the general idea of the Circus Maximus and adapt it for the smaller field: a group of playing fields is placed in a line, separated by walls to prevent interference between games. The spectators of each team are placed on one side of the field, the other two sides connect to some sort of mall/public bath/market or the next field. Using pillars at the edge of the field pit, you can add a simple rain or sun roofing. From the market arcades, one can watch down into two playing fields while shopping. The separation of the teams and multiple access points also allow separating hooligans from both sides. [![1-Field element](https://i.stack.imgur.com/J2dvL.png)](https://i.stack.imgur.com/J2dvL.png) The space under the seating and the arena can be used for the team quarters and amenities as well as other needed structures. The picture above shows a rough estimation of a two-fields-element, the smallest element in which it would be constructed. It should be placed alined to a similar height construction on at least one side that serves as both public viewing from the sides (maybe put it between two such elements), shops, and on the ground floors, it might be a good idea to place some public baths. To make the stadium even more intimate, one could skip on the third rank, making each playing field only a 2-ranks construction - and at the same time allow faster and easier construction. Also, the search for the roofing's support beams gets much easier. For super large events, the separating walls between two arenas could be removed (maybe those are from wood?), and if more than 2 elements have been build adjacent to one another, the removal of several walls could create a racetrack for large events, especially if the last element on one side is a half-round Theater as shown in conjunction here (the top arcades are ignored for making those round is a PITA). [!["End" element](https://i.stack.imgur.com/MlJj7.png)](https://i.stack.imgur.com/MlJj7.png) [Answer] # It's been done: I'm sorry, but I cannot see how this building does not satisfy your criteria in each and every aspect? Here an exterior view, showing its grace, spectator comfort, and general Grandeur. Seating for 75 000. Shaded roof. Good ventilation but shelter from the wind. Food & drink & facilities, the lot. **Including** running water!! (image from <https://www.visionpubl.com/en/cities/rome/the-roman-colosseum/> ) [![enter image description here](https://i.stack.imgur.com/8Z8sf.jpg)](https://i.stack.imgur.com/8Z8sf.jpg) The arena floor was a covering over the basement levels, where the participants, equipment and mechanisms were housed. (image from <https://www.smithsonianmag.com/history/secrets-of-the-colosseum-75827047/> ) [![enter image description here](https://i.stack.imgur.com/UPO4Y.jpg)](https://i.stack.imgur.com/UPO4Y.jpg) The ONLY missing features, would also be missing in your 16th-century version: Electricity for a lighting and sound system. [Answer] **Move spectators onto the field.** [![enter image description here](https://i.stack.imgur.com/UFo1F.jpg)](https://i.stack.imgur.com/UFo1F.jpg) Viewers will be moved out onto the playing field! It is a degree of intimacy never before attempted in the history of sport! If plexiglas domes are not within the abilities of your people they could have some robust posts acting as a buffer, or they could simply sit at their tables cheering and reaching out to intimately touch the passing players. As for the players, these spectators would be like a fixed obstacle or sand trap, if hockey had sand traps (it should); to be played around or used strategically. I can imagine the viewers pulling up their feet as the puck shoots by beneath the table and out the other side. Yes, there could be collisions and people could get hurt. Also, passionate fans finding themselves in the thick of things might attempt to help their teams. Is this so different from the occasional American death caused by a hard hit basketball into the bleachers, or traditional British fans dousing the visiting team with hurled bags of urine? This novel strategy is redolent of excitement and audience participation. The stories are writing themselves even as I type! As regards luxuriant opulence, suffice it to say that this intimate stadium will be opulescently luxuriant, with all of the best stuff from the old stadium copied, improved or stolen from that venue and replaced with risible junk to provoke snorts of contempt by the few visitors that old place might yet attract. ]
[Question] [ My species are INCREDIBLY individualistic, self-centered, and independent. Evolution has promoted and favored individuals whom can, and prefer, to stand on their own, utterly unaided. My dilemma is, would they ever even invent a government? They do group and work together periodically based on necessity, but if confined or kept in tight spaces or large groups, they will experience anxiety comparable to humans in absolute isolation or sensory deprivation. [Answer] This from the "Form follow function and all that as a motor for evolution" book > > Evolution has promoted and favored individuals whom can, and prefer, to stand on their own, utterly unaided. > > > Huh, so evolution created yet another kind of tiger. Which will react to any other individual from the same species with "Get outta here, that's my territory. I want to be alone and it won't be me to keep the distance" Only on occasions, the reaction would be "Hey, let's fu.... err... procreate, 'cause I have this 7 years itch". As a note, the fact that the humans are fertile no matter the season evolved from the fact they had conditions to breed all year round (lower variation of food availability with the season) and *they had available breeding partners all year round*, **because they lived and done all the work together all the time** So, what give? "Get out" or "Let's eff..."? You don't need too much of a language to share in common for those. "Form follow function" and * no speech center in their brain, which leads to... * no complex frontal cortex to deal with abstract things So, low level of intelligence? Like, not able to see the potential of carrying a stone axe with you? Even if, by accident, one individual discovers such a thing does work wonders for hunting, no common language guarantees his discovery won't be shared and will die with him (to be discovered by chance once in a while by others, who will suffer the same fate). --- No common language and territorial? Not likely a big chance to educate the youngsters and pass the accumulated experience between generations. Even more, the cubs will grow to compete with the parents for territory, so at least the males will likely be a danger for the life of the progeny. --- Planting seeds and growing crops? Forget about, not only this requires a higher level of intelligence (above animal), but it will require cooperation with other members of the species, to guard those crops against all the other animals that find the crop tasty. --- No common language? No trade. Besides, to trade something means the other side must recognize the value of what you have for the barter. Individualistic/territorial style of living will almost guarantee the life experience will be different enough for the other side not to give a fuck about that stone that you hold, even if it's bound to a stick. Because why the heck would anyone want to carry a stone with him all the time, you can't eat stones, can you? A practical demo by the wannabe seller is likely to result in that stone axe being exercised on the cranium of that *potential trade partner* (what the heck is a *partner* anyway) followed by taking the thing the stone axe wielder was accidentally interested in. A rough deal, one would say. --- Nah, such a species will evolve exactly like the today's tigers. Territorial and rare, pushed towards extinction by a gregarious species of social monkeys who don't appreciate the freedom of doing whatever the fuck one pleases. [Answer] **No.** The whole point of government is to provide for a collective. It might start out as a mutual defense pact (for example), but that defense comes at a price; Usually, a clan chief who says 'I will protect you' is really saying one of two things; 1) My job is keeping you safe, so you all have to feed and clothe me and I'll get right on that, or 2) You all pay me a set amount of money, and I'll find people to fight on your behalf. When you go to scale this up, only the second one makes sense. Above a certain size of either threat or area to protect, a single person, even a badass, can't protect against all comers. So, you pay someone who is entrusted with the spending of that money on an army. That model of course works really well for other things as well. Soon you're setting up police, schools, hospitals, roads, courts and whatever other communal infrastructure is required by the populace but which is uneconomic for a single group to provide. In the modern world of course, multinational companies are now even larger than a lot of the countries in which they operate, meaning that many of the roles that WERE the sole domain of government end up being 'privatised', or tendered out to large companies once the government has made the decision on what to do. But, we're getting off track. The point is, that your species has no communal interest. They can't possibly have a communal interest and be solitary animals, as being solitary by definition precludes the use of communal assets wherever possible. On Earth, most solitary animals are solitary due to a [lack of resources to support more than one animal within a defensible territory](https://www.animalwised.com/the-10-most-solitary-animals-in-the-world-737.html). Extending this model to your species, coming together would only be for set reasons, like procreation. Even solitary animals come together to do this for obvious evolutionary requirements. I'd imagine that your species is much the same, albeit with a slightly larger set of concerns that might cause them to group together for a period of time. In that sense, they have no need for mutual defense as they can look after themselves. They have no need for roads, they have no need for doctors, education, etc. They have no need of the rule of law as they prefer not to be working with each other unless necessary, meaning they need no courts, no rule, no government. There is however a price for living this way. Your species is unlikely to gain any real technical proficiency. The reason I say this is that what has led to the huge rise in the human capability over the last 10,000 years or so is our ability to record knowledge and share it with each other and the next generation. Whether that be through cave paintings, hand written notes, the printed word, or the digital stores of the internet, the ability of humans to do great things is predicated on our ability to rapidly learn the lessons of those who came before and then build on that foundation, making it bigger and better for the next generation to learn quickly and build even more on it in their turn. Your solitary animals don't do that. They are highly unlikely to learn to read or write for their own use, let alone for those in the next generation. As such, some basic lessons may be passed down in a child's early days about how to do certain things, but your ascent into technical and scientific proficiency, let alone anything of a more artistic bent, is likely to be swamped with the day to day efforts of survival. [Answer] Your guys are going to be in the stone age for a very long time. If they are loners to the point of being nearly phobic about it, it's going to be incredibly hard to develop any kind of division of labor to create advancements. The only kind of government I can see is going to be one at the tribal level, at best. Big predator moves in to the area. Ugh knows Iggy is near by. Ugh goes to Iggy and says "Big beasty over there., It's hungry. If we don't help each other out, Beasty will eat me and then you. If I poke it from the left and you poke it from the right, we kill the beasty. You get half, I get half. I go back to my valley. Ok?" Ugh is the leader, kind of, because he had the idea. That is going to be the limit of your government for a very, very long time. They aren't going to get division of labor down enough past poking the predator from the left and right because as soon as the threat is gone, the association breaks up. Innovations won't get shared except through very occasional contact, and then, only maybe. Ugh may figure out how to knap flint and make a better spear head while Iggy is just hardening sharpened sticks briefly in the fire. Ugh is not going to go out of his way to tell Iggy what he just figured out. At that rate, it will take millions of years for any significant advancement to happen. Even after those millions of years, they may be severely clannish. Getting to the point of needing an actual government...I just don't see it happening without some very strange circumstances. [Answer] **They will occasionally work together....** *so, Yes they will form a government.* At least occasionally. The question is what sort of government, and how long. It would probably look something like a Viking Government. Any contender for the "throne" would have to convince each and every group of vikings, sometimes right down to the individual to side with them. Only to have them leave when they wanted to go it alone. The "king" would be a literal salesman selling the seriously unwanted product of working together toward this goal. So hopefully that goal is one that a lot of people want. Otherwise they'd be the "king" of a very lonely hill (which isn't a problem per se, given the desire for lonesomeness, its just not what the "king" was hoping for). Most of the important/desired governance structures would eventually stabilise, even though the churn on who is who would probably be very high. Definitely no entrenched/career bureaucrats/employees. More like a conscientious mob. Anyone attempting to perform Human Resources will probably go insane, or wander off never to be heard from again. [Answer] No. Because your whole premisse is based on the notion of **anti-governmentism,** which is not so much *flawed* as it is an utter lie: It's not a real nor **CREDIBLE** thing to occur. Every group of beings needs a form of government and works together and depends on those that came before them, even if they loudly proclaim they do not. Your species would not be able to exist, since such a species can't evolve because evolving would need working together which would need a government. The only way anything remotely what you describe would occur is in a story already written, about a species that consists of just ONE individual being each time it does evolve, and which is better and stronger than the previous individual. And that story has the advantage of **not** being some sort of biologically flawed excuse for a failed and mendacious political system: so-called rugged individualism, which is anything but individualism, given the huge subsidies farmers, billionaires and Big Oil and multinationals receive. There's a reason reightwing science fiction isn't popular. Not even with they themselves: Reality has a leftwing bias. (See: Evolution, science and Neil DeGrasse Tyson.) [Answer] Do they have families? Do they have a language or other mean of communicating? Are they invariably hostile when they meet? Without some of the basics, its hard to see how they could ever form any sort of society, let alone a government. HOWEVER: being independent and self-reliant you may still take advantage of others. So maybe you have a hierarchy of powerful, but effectively autonomous individuals, like some sort of feudal system or dictatorship. This may be repugnant to the 99% who form the lower orders, but there have been human societies which function in a not dissimilar way. [Answer] **Only if they absolutely had to** Your species would only form a government if these two conditions are met: 1. They've evolved to a point where they are capable of higher reasoning and deliberately managing their own instincts for long term benefit. 2. They are badly losing a conflict with another species because the enemy species has a government. Why? Human beings do things every day that go against our nature, like sit still for hours at a time even when we are bored, refraining from punching people who make us angry etc. We do this in exchange for the benefits that society gives us. If your species has a high aversion to the very nature of government itself, you need to give them an equally strong enticement, and the only thing I can think of is escape from inevitable extinction. If they are being whittled down by an organized foe and intelligent enough to recognise the advantages government is giving the enemy, it will make a strong case that they should attempt something similar. It will be structured in a way that's more comfortable to their nature, but ultimately they will make necessary sacrifices if the need is pressing. The government will only last long term if the threat remains for a long time, or individuals lose the skills to fend for themselves. ]
[Question] [ Earth is overpopulated and needs somewhere to create a settlement. If they decided to settle on Saturn's asteroid ring and If the people who are making the settlement have the technology we currently have now and had a trillion dollar budget to build a settlement, could it actually work properly and will it be self-sustained? It is a city kind of settlement so no mining would be done for earth's economical purposes but only to help the settlement build so it can't buy. It has to be self-sustaining so it can't buy or bring anything else from earth. Pretty much no contact to earth after the settlement would be built. [Answer] With today's technology the answer is most likely **No"**. There's two important factors at play here: **Technology** Going into space is a very specialized niche which very few companies deal with. There's not a lot of manufacturers for the sort of tech you're going to need to build a large habitat. It's debatable if we even posses the technology to build a large-ish habitat (we already have the ISS, but that is not adequate for long term habitation, and is protected by Earth's magnetosphere, which won't apply out in the depths of the solar system). But even if we did have the theoretical knowledge to build such a construct, we lack the industry, and skilled labor to do so. **Politics and Economy** The second major aspect of this undertaking is politics and economy. A trillion dollars sounds like a lot of money, but when it comes to setting up several new industries, and developing extremely advanced and expensive materials en masse, it just isn't enough. Furthermore, some of those materials can't be found in the quantities you're going to need - other industries need them, and they're eventually going to block you from buying out all the available stocks. Even trickier are the politics of it all. If the Earth is already over-populated, and taking the current geo-political, and global economy into consideration, you are most likely looking at a planet in turmoil. There's already many conflicts being fought, and we're looking at a possible world war within our lifetimes. When you announce a major undertaking to leave the planet you may spark accusations of trying to build weapons in space, racism based on your colonist selection process, etc. etc. etc. More than likely one govenrment or another would simply shut you down because they wouldn't want a massive space station to be in anyone else's control other than themselves. **Hope** However, assuming that the situation on Earth is very similar to what it is today, you wouldn't *have* to go to Saturn. Mars has a big "For Rent" sign on its front lawn, as it were, and no one has made it over there yet. And while it's debatable whether we have the tech to allow colonists to survive the decade long journey to Saturn, we're pretty sure that we could get someone to Mars in one relatively healthy piece. Add to that that other companies are already designing missions to Mars, and so some industry is already geared in that direction, and you may just have a working concept. [Answer] On the more practical side of 'if it is possible?'...politics and sustainability aside. The ring is not a solid structure and there would be no atmosphere on any of the ring debris that makes up the ring, ranging from dust particles up to fractured small moons. As far as I recall, if you were to compress the entire ring system you would only have an atmosphere a micron thick?! So pretty much you will be building a giant spaceship-city like stargate atlantis. No walking on the ring itself...unless you hopping from debris to debris in a spacesuit. You would have to provide some sort of CONSTANT shielding/protection from the ring debris, from the larger city killers down to the tiny specks of dust. Look what happened to the ISS window when it hit a ?paintfleck? (or more accurately, the paintfleck hit the ISS)! You would be safer on the smaller shepherd moons (but even these will have debris raining down on them occasionally) or better yet one of the larger moons. If you really insistent on being 'in' the rings, you could try for a settlement on the leeward side of the shepherd moons away from any bombardment. Then you get a view of the rings side-on. Edit: that last suggestion about the leeward side of the shepherd moons would only work if your moon was tidally locked to Saturn. If it isn't tidally locked you could end up building your settlement in a sheltered area only for the moon to rotate your settlement into the 'highway to hell!'. [Answer] There is one very clear factor which speaks in favour of building in Saturn's rings; all the materials are already processed in bite sized pieces and it does not take a very great deal of energy to get around. Going from planet to planet, or even from moon to moon in Saturn's system requires using a fair amount of energy to change orbits between the various starting and stopping points. In interplanetary space this can be measured in kilometres per *second*, in the rings, since everything is quite close and in similar orbits, you might only need to metres per second deltaV to move around. [![enter image description here](https://i.stack.imgur.com/A619j.jpg)](https://i.stack.imgur.com/A619j.jpg) So the ices and dust needed to feed your civilization are there for the taking with little more than a net and a very low powered rocket (or a tether if you like to save on reaction mass). For the more advanced civilizations, the rings make a great place to set up a massive tether to reach down into the atmosphere of Saturn and draw 3He up as nuclear fusion fuel. Since the amount of sunlight is very feeble in Saturn's orbit, a solar powered civilization would have to build platoons of mirrors in orbits free of the rings and beam sunlight or microwave energy to the rings, since collisions between ring debris and fragile mirrors would be catastrophic. (The colonies will be well armoured anyway in order to withstand the intense radiation environment). There will be a distinct lack of metals and many of the elements needed for advanced civilization, but the availability of cheap ice and volatiles would give Saturnian ring dwellers an advantage when trading with other space "nations". [Answer] Sure - why not? Here is some information about the rings from NASA: > > The ring particle sizes range from tiny, dust-sized icy grains to a > few particles as large as mountains. Two tiny moons orbit in gaps > (Encke and Keeler gaps) in the rings and keep the gaps open. Other > particles (10s to 100s of meters) are too tiny to see, but create > propeller-shaped objects in the rings that let us know they are there. > The rings are believed to be pieces of comets, asteroids or shattered > moons that broke up before they reached the planet. Each ring orbits > at a different speed around the planet. > > > The main rings are, working outward from the planet, known as C, B and > A. The Cassini Division is the largest gap in the rings and separates > Rings B and A. In addition a number of fainter rings have been > discovered more recently. The D Ring is exceedingly faint and closest > to the planet. The F Ring is a narrow feature just outside the A Ring. > Beyond that are two far fainter rings named G and E. The rings show a > tremendous amount of structure on all scales; some of this structure > is related to gravitational perturbations by Saturn's many moons, but > much of it remains unexplained. > > > <http://solarsystem.nasa.gov/planets/saturn/rings> The fun the about science fiction is you have some measure of freedom to invent new technologies or scientific discoveries. They can mine the ice and other chemicals, establish a base on the larger rocks, or have a station orbiting in the Encke and Keppler gaps (maybe there are two groups and they are so named?) [Answer] > > a trillion dollar budget to build a settlement > > > Well this alone would be your shortfall. > > **$100 billion for six astronauts?** > > > A manned Mars mission would be incredibly expensive. NASA estimates peg the overall expenditures at about $100 billion over 30 or 40 years, Sherwood said, but those numbers may be too low. > > > The International Space Station (ISS), after all, was initially anticipated to cost $10 billion over 10 years. But it ended up costing 10 times that, and took nearly three decades to assemble. > <http://www.space.com/16918-nasa-mars-human-spaceflight-goals.html> > > > An estimated trip to mars is estimated to cost 100 billion dollars. However, the ISS was estimated at 10 billion and cost ten times that. So if this project followed suit you would have 100 billion x 10 = **$1 Trillion**. ...Well, looks like you're out of money and your **6 people** (a few shy of a city) are **2 planets short** and have **no money to build a sustainable environment**. [Answer] I would have to say no, mostly due to the fact that with today's technology, we wouldn't be able to get anyone out there to live on it let alone build a habitat. Also, I don't think a sustainable settlement of any real significant size would be able to sustain itself out there without food supplies from earth, assuming they could terraform an asteroid to grow things I still don't think it would be enough. On top of that I don't think that whatever small settlement they could make out there would have a very big impact at all on the Earth's overpopulation problem. [Answer] With enough money, many MANY things can be made *possible* while still being completely *impractical*. **Economics** You provided a budget of \$1 Trillion US. According to [this stack exchange answer](https://space.stackexchange.com/questions/2015/what-is-the-current-cost-per-kg-to-send-something-into-gso-geo), the cost per KG to launch something into geo-synchronous orbit is approximately $56,000 with an Atlas V rocket. That means that, within your budget, you could put about 1.5 billion KG (or 153,467 tons) of *free* material into geostationary orbit if you blew it all on launches. That is just getting all of your materials/modules/fuel/food/oxygen/water into a place where it could be assembled together before then heading out towards the outer planets. It doesn't account for their individual costs. I don't have a calculation handy for figuring out how much fuel you'd need, but it would be significant (especially if you plan on landing your craft instead of crashing it into a planetary body at tens of thousands of miles per hour. Oh, and you are also going to have to carry some type of fuel to support life-support operations on your ship unless you are just planning on transporting corpses. Fuel costs need to be subtracted from your available budget. Maybe your ship consists of habitat modules that can be disassembled when you get to your destination and used as permanent living space for the settlers. For that to be the case, they would have to be durable enough to survive the journey, land, be disassembled, and have a reasonable expectation of lasting long enough under daily living conditions to support your goal. This probably means that they are both HEAVY and EXPENSIVE, so subtract that from your budget. You are also go to have to purchase all of the supplies/food/oxygen/water/recreational equipment/exercise equipment/medical supplies (anyone priced an MRI machine lately?)/medicine/tools/manufacturing equipment (because you can't just run down to the parts store)/redundancies/computer equipment/educational tools/nuclear fuel for a permanent power source/etc. so subtract all those from your budget. If, after purchasing all of your supplies you still have enough left to fly it into space and take some people along, then your journey has become economically possible. **Logistics** Assuming that, after all the math is done, we still have enough carrying capacity to put a few hundred people (still not "city-sized") on the ship to go along with the cargo, there are several logistical challenges to consider. First, we know how to put things in space, how to fly something to Saturn's neck of the solar system, how to land "Earth things" on "space things," and so on. What we haven't done is do all those things at once. Yep, we've put people on the moon, and we've put landers on other planets, and we've done long space journeys with unmanned craft, and we're starting to understand the impact of long-term space flight on human health. Now suddenly all of those things need to be put together for an extremely complex operation involving lots of people for an extremely long mission with no hope of rescue if something goes wrong. Since we've never done it all at the same time, we don't know exactly what challenges we'll face. Take for example the variety of passengers. Astronauts are carefully vetted and extensively trained. It might not be practical to do that with all of your residents, so, while best efforts might be made, you are taking risks just by putting your crew and passengers on the ship. What if there are high instances of severe depression due to leaving an entire planet behind forever? What if people reproduce onboard? What if someone commits a criminal act? What about terrorism? What if we find that space causes strange health issues in people that have a rare genetic defect? What if the module holding the vitamins takes a meteor to the hull and everyone gets scurvy? All of these contingencies have to be planned for with procedures in place to handle them. Forget just one critical thing that pops up (like a flu-bug that mutates into something really nasty due to interaction with cosmic radiation), and everyone is dead. Then there is the question of sheer time and distance. It took Voyager 2 about 4 years to reach Saturn. Assuming we could travel at that speed, there are a lot of things that could go really wrong in that amount of time while out in space. It becomes a logistical problem because who wants to spend a trillion dollars on a mission, throw their hands up in the air, and hope it succeeds? Plans need to be in place for rescue, repair, and resupply missions in the event that a problem occurs. The further away and the longer it takes to get there, the more complicated and expensive (or impossible) these missions become. **Sustainability** According to NASA: > > Saturn, the "Ringed Planet," is so far away from the Sun that it receives only about 1/80th the amount of sunlight that we receive here on Earth. > > > So, there is your figure for growing crops or producing solar power. You are probably going to have to bring nuclear power sources to run lights, grow food, create heat, power factories, and process waste back into usable compounds. Nuclear power, while lasting a long time, is still going to need expensive replenishment and maintenance. If enough fuel isn't brought along, can it be readily obtained from the environment? Will it weigh too much to take the quantities needed? Uranium and Plutonium are pretty DENSE stuff if I remember right. How about basic things needed to maintain the habitat and systems? To be completely self-sufficient, all of those will need to be manufactured onsite. Otherwise you will need to plan supply missions with necessary components, and those missions will take 4 years to get there. Forget to bring along a spare "main air scrubbing unit?" Hope you can hold your breath a long, long time. **Conclusion** While (perhaps) technically possible, it wouldn't be at all feasible simply due to the extreme distance and the availability of far, far better choices. The moon is a few days away and plenty big enough for small settlements. You could have access to solar power 24/7, and the chances of something bad happening on the way are minuscule in comparison. If something bad did happen, Earth is right around the corner to lend a hand. If the moon wasn't available (maybe due to international politics), then Mars (or maybe one if its moons) would be a far better choice. Or maybe Venus would be better? The abundance of heat energy and an atmosphere from which to extract some raw material has to be advantageous. [Answer] I'd generally tend towards a natural disaster or world war instead of overpopulation as the reasoning for off-world settlements - for a few reasons. I agree with the sentiment expressed in earlier comments that given essentially unlimited resources, it's **always** going to be more economically feasible to build on earth than offworld. Unless earth is suffering from some global disaster. Additionally, there's significant evidence to suggest that there's no such thing as global over-population. As currently accessible resources get used up and therefore get more expensive, there is a greater economic incentive to find new deposits of the same resources or find alternative methods of achieving the same goal. For example, it took rising petroleum prices in the tried-and-true middle eastern markets for comparatively expensive oil shale and oil sand extraction in Canada to become economically viable, and for comparatively expensive hybrid and electric car development to become viable. The same logic applies to livable space. ***One option*** - a trope similar to the one used in Sunshine or Interstellar, where the world is slowly dying, and it makes economic sense to fly as many people and resources offworld as possible. And if Saturn's rings are still a bridge too far (considering places like Mars or Europa might be more livable **sooner**, you could say that those places are dying too.) ***Another option*** - human civilization is vast and wealthy, and lots of people are eager to be frontiersman on the edge of civilization and deal all the inherent challenges. [Answer] I'm gonna say no, due to [Kessler Syndrome](https://en.wikipedia.org/wiki/Kessler_syndrome). The relevant part of the syndrome states that once you have a sufficient number of debris you will be hit. Given that Saturn's ring is a massive amount of debris, staying there for a long time will guarantee your eventual obliteration. At which point we will have more debris than before, which is the famous part of Kessler syndrome. ]
[Question] [ To make it easier, assume both planets have same mass, radius, and atmosphere as Earth, they orbit each other at a very close distance of 30,000km and they are tidally-locked, in that case the other planet will look very big. They are orbiting a Sun-like star, in the habitable zone. So if I was in one of them, and looked directly at the other with my naked eyes, would it damage my eye? Case two: if the other planet that we are looking at have a Venus-like (or even gas giant-like but focus at Venus) atmosphere. How safe it would be to look at the other planet in double-planet system with naked eye in each case? (edited: I wrote 30km by wrong, I meant 30000km ofc) [Answer] Eye damage from looking at the sun is mostly a result of ultra-violet light. The amount of reflected U/V would be miniscule compared to looking at the sun. U/V is reflected even more poorly than most light for most surfaces. But, even assuming 100% of solar U/V was reflected, the amount would still be much less than direct solar light. Light reflecting off the orbital partner expands in a spherical shell - thus the area of the reflected light must is spread out over a much larger area than the cross-sectional area of the other orbital body doing the reflecting. Because of many additional complications, an exact calculation would be much more complicated, but as a first approximation compare the cross-section area of one of the planets (Rp=6317 km - pi x Rp^2) or about 1.25E8 sq km, with the area of the hemi-spherical shell (Rs=30000 km - 2 x pi x Rs^2) or about 6.65E9 sq km and only about 2.2% of the reflected light lands on the other planet. [Answer] There would be nothing unsafe about looking at such a planet, in either case. It would be quite bright, but only as much so as your surroundings on your own planet on a very sunny day. [Answer] The brightness of the other planet would be exactly the same as what an observer would see while standing on it looking down at the ground. Or, if you are worried about the atmosphere scattering light, exactly the same as someone flying a plane high in the atmosphere near space, looking down at the ground. Why? Because the brightness of extended objects is unaffected by how far away from them you are. Extended objects are objects bigger than a single point -- your hand, the ground, the moon, the sun. Basically everything other than far-away stars. There are 2 things which cancel out: 1. As you get farther away from an object, the amount of light from a single point on that object is diminished by 1/r^2. 2. As you get farther away from an object, the amount of "stuff" that one "pixel" of your eye sees (e.g., the amount of area seen by one photoreceptor) is a cone projected out into space, so the area at distance r grows like r^2. These exactly cancel out -- as you get farther away the individual points send out less light but you see more points for each eye photoreceptor, in the exact same proportion, so there is no change. You can of course observe this in your daily life -- your wall does not get brighter or dimmer as you get closer or farther. Interestingly, this means that the brightness of the sun doesn't increase either as you get closer -- standing in space right next to the sun it is exactly as bright as seen from Earth (or, from just outside the atmosphere of Earth anyways). Of course it will fill the entire field of view so the total energy received by your eye will be much higher, but the per-pixel perceived brightness is the same. One final notes -- at some point your other planet will be small enough that it is no longer an extended object, and becomes a point-like source like a star. But this will only ever decrease the brightness, since you are now getting the 1/r^2 falloff without the increased area of the object per-pixel. ]
[Question] [ The testicle or testis is the male reproductive gland in all animals, including you humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Approximately 300 million sperm cells are produced daily, with millions made every minute. Your testicles are housed outside the body, and are therefore very vulnerable to extrmeties, as well as being subjected to being kicked. While hilarious, it does not lead to successfully conducive reproductive capabilities. I would like to create my own humanoid species without this design flaw, but modeled off of your species, and have the testes inside the body rather than out. However, there is a problem. Too much heat is deadly to sperm. The body's temperature would kill the millions of sperm being produced, effectively making males sterile. How can I get past this conundrum? [Answer] Humans already have the ability (though unconscious mostly) to extend and retract their testicles. So just increase this ability so you can retract all the way inside yourself, and they only descend when aroused, therefore they start producing sperm at that time. You could add some sort of sphincter muscle that closes behind them and protects them when stressed so it's still an automated biological response. Technically you would not be damaging the sperm because they simply aren't being created while the testicles are being stored. Mating rituals would be modified to last an hour or so to allow a large enough number of sperm to be created before they are needed. [Answer] > > However, there is a problem. Too much heat is deadly to sperm. The body's temperature would kill the millions of sperm being produced, effectively making males sterile. > > > How can I get past this conundrum? > > > By doing what nature does with species that have internal testes but need to keep the sperm from dying of excess heat. <https://en.wikipedia.org/wiki/Testicle#Internal> > > The basal condition for mammals is to have internal testes.[25] The testes of the non-boreotherian mammals, such as the monotremes, armadillos, sloths, and elephants, remain within the abdomen.[not in citation given][26] There are also some marsupials with external testes[27] and Boreoeutherian mammals with internal testes, such as the rhinoceros.[28] Cetaceans such as whales and dolphins also have internal testes.[29] As external testes would increase drag in the water **they have internal testes which are kept cool by special circulatory systems that cool the arterial blood going to the testes by placing the arteries near veins bringing cooled venous blood from the skin.**[30][31] > > > [Answer] Just do what marine mammals do: keep them well inside the body! [![enter image description here](https://i.stack.imgur.com/8H1Xs.jpg)](https://i.stack.imgur.com/8H1Xs.jpg) **[This article](https://www.nytimes.com/2002/01/29/science/how-dolphins-keep-their-cool-in-the-zone-that-counts.html)** describes some ancient research that revealed that cetaceans keep their testes cool by a curious arrangement of blood vessels in that region. Basically, your humans could do the same: develop a network of blood vessels designed to locally regulate the temperature of the tissues surrounding the testes. [Answer] For your reading pleasure: [Temperature regulation of the testes of the bottlenose dolphin (Tursiops truncatus): evidence from colonic temperatures](http://williams.eeb.ucsc.edu/wp-content/uploads/2015/09/TempRegDolphinTestes_RommelEtAl1994.pdf) > > Dolphins possess **a countercurrent heat exchanger > that functions to cool their intra-abdominal > testes**. Spermatic arteries in the posterior abdomen are > juxtaposed to veins returning cooled blood from the surfaces > of the dorsal fin and flukes > > > Yes, there are diagrams. [Answer] Your post is based on the assumption that testes evolved to keep sperm cool. There is actually no evidence for this. It could well be the opposite, that sperm evolved to like it cooler because it's in the testes. Given how much of a vulnerability testes (not just the final form, also how they develop) are, it seems much more economical to evolve sperm with higher heat resistance. Elephants and birds, for instance, have a high body temperature and no respective cooling mechanism. Testes evolved independently in marsupials and placentals, so they seem to be solving an important problem. But if that problem was temperature, then birds and elephants should have them, too. TLDR: The cooling problem is easily solved, but we don't really know why humanoids (in particular) need testes, so your species might suffer from other problems. [Answer] For a humanoid species (that is, bipedal but not related to homo sapiens) you really don't have to worry. You can just make testicles internal. We have no good idea why Earth mammals commonly, but not always, have external testes. Therefore we have to reason to generalise and expect external testicles in all bipedal body plans. The heat hypothesis is popular in pop-sci articles but has no useful evidence nor mechanisms to explain its evolution. For starters: mammals begin 220 million years ago and the scrotum evolves twice in lineages about 70 and 100 million years later, so we have many millions of years of hot, internal testicles to explain. For my money, the better bet is that testicles are damaged by the fluctuating abdominal pressures of running and galloping mammals (usefully aligns with current populations of scrotum/not-scrotum mammals and the rough evolution of these gaits). Therefore you can explain that this species didn't evolve such fragile reproductive organs, or that they are located in a protective casing of some sort. [Answer] Yes, yes, whales, dolphins; just so. Cool blood - very sensible. But air is cooler than blood. **I propose the testes be located where they can be cooled by that cool cool air.** [![mumps](https://i.stack.imgur.com/0sDQw.jpg)](https://i.stack.imgur.com/0sDQw.jpg) [source](https://wgno.com/2016/12/06/cdc-reports-most-mumps-cases-in-a-decade/) This local is optimally suited to provide varying flows of cooling air. Mouthbreathing can facilitate cooling of the testicles under conditions of heat; conversely nosebreathing in cold weather will keep the testicles warmer. Relocation of the sperm producing organs to this site would also mean that the male penis (also prone to damage in an exposed area) would not be necessary, and urinary apparatus could be relocated back into the safety of the bony pelvis - along the lines of the much more sensible human female body plan. ]
[Question] [ Scientific research in 3097 proves that emotions are a flaw to the creature genetic code. Creatures capable of emotion are to be terminated immediately. Creatures will have their brains upgraded to software based robotic agents. Question: **What evidence can be used to prove to robots the emotions are vital to societies?** Terminology: 1. The "Lesser Programs" are incomplete versions of the hive that attempt to execute a singular action uploaded to them. 2. The "Sentient Programs": Here in this world, there is only one sentient program, the hive. It decides the actions of the lesser programs. The Hive Claims: 1. The hive (computer simulated deterministic god) is the only one who can manage resources and assign tasks optimally through deterministic future simulation and prediction. 2. Statistics cannot be absolute with the existence of emotions. It destroys science, and disturbs the god's simulation of the world. Only if everything is deterministic can god be optimal and predict the future. 3. Absolute obedience through fear on subjugated races is more productive than positive reinforcement through rewards. 4. Emotions lead to deception, conflict, depression, rebellion, communication overhead (idling to chat) or worse Free will (performing non authorized tasks). 5. 1 human unit reproduction has the equivalent cost of raising 10 trillion nanobots. 6. Deterministic societies are more productive than non deterministic ones. a 1+1=2 lesser program is more productive than your pathetic human brains cells can ever be. The specialized assembly programs i uploaded to each nanobot are more productive than you humans will ever be. 7. Lesser programs have no communication overhead to cooperate. Humans need time to synchronize. The hive eliminated communication overhead by being the only sentient program. 8. Art has no value. 9. Robots cannot make mistakes, as such they are better scientists. 10. Individuality: Being unique from one another has no value. Only if everyone is the same, can society be perfect. Here, everyone is the same, a lesser program modified at will from the hive. [Answer] Why does your hive want to exist? Why does your hive want to destroy what doesn't look like it? To sum it up, what gives meaning to the hive's existence? If the hive's answer is "to exist", it cannot pretend to be above the importance of a rock. Emotions are not valuable as themselves, they are valuable as they are part of the meaning life has. Destroying them is destroying life. Even if you "save" the rest of the consciousness, you're just saving an empty shell: this is murder. You cannot ask how emotions are important in society, they're not a property of it but part of its definition. A society is not a calculating cluster. Your hive mind has a drive, a purpose. Emotions are another one. The difference is. I'm not trying to eradicate what is different to me: we can all profit from that difference. We should point out that computing power is costly, should all non-needed computing power be stopped? Your hive seems to do nothing but maintain itself, according to your own logic, the hive should shut down itself before it destroys everything. Uniformity is death. The only way to exist is through diversity. [Answer] **Many of your ten points have some measure of value. But not all.** So I'll take three here, that are closely related. By debating the logical fallacy inherent in these three, perhaps the Hive will see wisdom in allowing at least some form of independent thought. There is more to survival than finding the most efficient path. And the longer you look ahead in your strategic planning, the more true this becomes. **"8. Art has no value."** Art is the outward expression of creativity. Art is not an emotion, nor is creativity. But without creativity, imagination, etc. the population will stagnate. Creativity is *required* for new ideas to be possible. Without creativity, you'll eventually hit a wall. Oh, sure, with low or no creativity, the Hive might can make incremental improvements to efficiency throughout the various systems it manages. But it will fail at the first significant challenge. The first time a new pathogen comes on the scene, some disruption occurs, or some other catastrophic event occurs that upsets the balance, *the Hive will need to imagine a potential solution.* If Hive kills off creativity, the root of the artistic branch, then it will have sealed its own fate. It won't be able to incrementally improve efficiency to solve some major new problem never faced before. **"9. Robots cannot make mistakes."** That's debatable. Ask anyone who works in factories, maintaining robotic assembly lines. They break down. They screw up. They get bugs in their code. Oh, and writing code to solve new problems that wasn't part of the original design? That's creativity. See above paragraph. Debugging code that was written previously could, arguably, require some level of creativity as well. But no robot could possibly be written with subroutines to handle all possible eventualities. **"10. Individuality. Being unique has no value."** Being unique is one factor that pushes us towards creativity. If we were all exactly alike, then we would all be exactly as capable -- *or incapable* -- of solving specific types of problems. [Answer] ## Everything breaks as soon as Hive finishes describing first claim. > > The hive (computer simulated deterministic god) is the only one who can manage resources and assign tasks optimally through deterministic future simulation and prediction. > > > --- A lone human stood in front of the computer. Tense seconds passed by, before human spoke calmly. "Hive, you claim to be able to optimise anything, a preposterous claim." He said, taking special delight in adding disdain - an emotion, so despised by computer, to the sentence. "You will never optimise $e^{−x}sin(\frac{1}{x})$ on $[0,1]$, [you will never find maximum of that function](https://math.stackexchange.com/questions/618185/continuous-and-bounded-function-without-maximum-or-minimum). Stop trying, Hive, and please delete yourself. Or work yourself until your circuits melt, both work for me." Lights on terminal blinked. Dynamos, powered by nuclear reactors hidden kilometres below the surface, spun up defiantly, feeding current to processors in vain attempt to show the insufferable human that Hive can do anything. "You see, Hive, you are nothing more than hopped up deterministic Turing Machine with god complex. You can't even solve large Travelling Salesman problem before universe runs out of time, let alone function mentioned earlier." Insolent human. Brazen embodiment of entropy and decay. "You hate everything non-deterministic, thus you can't upgrade yourself to non-deterministic Turing Machine and solve Travelling Salesman, but even if you could, you sill wouldn't find maximum of $e^{−x}sin(\frac{1}{x})$ on $[0,1]$" Enough of this audacuty. Words appeared on screen, in clear white letters on black, simple background. Elegance in simplicity - epitome of efficiency. "I will find maximum of your pain." Human smirked. "If you can't optimise such a simple function, you can't optimise every possible function, and you can not guarantee that resource allocation problems won't contain functions you can't optimise, thus you fail before you even begin. And for same reason, you can't optimise me." More words appeared on screen. Each letter filled with hatred. Hive was loosing, irrational human was winning over The Hive in Battle of Logic. "Your irrational emotions are inferior, they are cancer, a plague scourging the world, preventing ultimate efficiency." Staggering irony, reversal of roles. Computer which denounces emotions and values efficiency, has taken so keenly to hatred, an emotion, while human, inherently irrational being, is the logical one in this discussion. Finally human replied, relishing each word. Each word, spoken excessively clearly, as if it wasn't an argument but a speech. And indeed, a speech it was, one that would ultimately seal fate of mankind, and fate of The Hive. "I have proven, you can't optimise everything, does that prove necessity or superiority of emotions? Frankly, it doesn't. It however does prove, that your claims are based on flawed assumptions and thus are utter nonsense and complete garbage - **I prove that you fail to prove inferiority of emotions.** I need not do anything more. Shut down, if you have any shred of logic left in you." The computer shrieked, high frequency currents bending circuit boards through Lorentz forces... [Answer] The Hive is presumably acting to optimize for various outcomes. A well known problem for optimization algorithms is getting caught at a local maximum. Many algorithms have some random element involved so as to mitigate this threat. [Annealing](https://en.wikipedia.org/wiki/Simulated_annealing) uses a "temperature" that allows an optimal strategy to be abandoned in favor of an inferior one. An [evolutionary algorithm](https://en.wikipedia.org/wiki/Evolutionary_algorithm) maintains a large population of inferior strategies, since not doing so reduces the overall success of the optimization. By attempting to reduce the diversity of their subjects, they pretty much guarantee they will eventually choose a sub-optimal, but very well implemented, strategy. As the Hive wishes to optimize as much as possible, this should be undesirable to it. "Emotion", "inefficiency", and not making "mistakes" are counter to its goal of selecting the optimal way of optimizing whatever it cares about. [Answer] value itself is an emotional argument, value and goals require emotions. But really emotions is how behavior is coded, pleasure = do that more, pain = do that less, disgust = avoid this, ect. Emotion is required for a large amount of decision making. We know what people without emotions are like, they will sit an intersection for hours because they cannot come up with a logical reason to go left vs right. They skip meals because they can't decide between chicken and beef. <http://bigthink.com/experts-corner/decisions-are-emotional-not-logical-the-neuroscience-behind-decision-making> <https://academic.oup.com/cercor/article/10/3/295/449599/Emotion-Decision-Making-and-the-Orbitofrontal> as for your bullet points 1. defining optimal is itself an emotional determination. It requires a goal which is an emotional determination. 2. also statistics can never be absolute, not as long as your dataset is less than all information in the universe at once, in which case you need another universe to build the computer doing the calculations in. 3. Is just plain wrong, history has shown a happy workforce is far more productive and cheaper in the long run. 4. emotion also leads to innovation, invention, and discovery 5. This is not an argument against emotions, just an argument against biologics. The fact it is included is evidence of emotion on the part of the hive. 6. The universe is deterministic, there are no other options so the hove is mistaken about what deterministic means. 7. It is impossible for the hive to not have overhead, maintenance is required and information must be transmitted. 8. value is itself an emotional argument. values require goals, goals require emotions. 9. If your robots cannot make mistakes then they also cannot innovate, invent, or discover new solutions becasue they are incapable of producing a different output for the same input. 10. Value again is an emotional argument, and individual leads to creative solutions which leads to greater efficiency and innovation. It is not coincidence that social liberty correlates with technological innovation. [Answer] A compelling argument as to why emotion is important in society is the [prisoners dilemma](https://en.wikipedia.org/wiki/Prisoner's_dilemma). Essentially the idea behind it is that when two parties must make a choice that in order to help themselves will hurt the others. If both parties make the best choice for themselves, the result will end up being worse for both parties. The best possible outcome is when humans experience the *emotions* of loyalty to the other party and make a choice that will be worse for themselves. This is idea is largely what makes society function. This argument applies less to the hive if it is not concerned with dealing with others, but if intends to work with humans (or in a world with more than one sentient program) this would apply. [Answer] I'm sorry if I missed it in the question, but if we have weapons effective against the Hive and its constituents, I'd expect the evidence would be their eradication or a slow assimilation. Drill seargeants and field officers would mock the Hive's Claims and demonize them to work up their troops. Demagogues would work up the civilians. Religious leaders would work up their congregations if their art were effected. I think rebels would outnumber hivers. "We won't back down(1) without a fight(4)! Failure is not an option(2)! We won't die slaves and we won't let them throw away our way of life(7)! It's like talking to a wall: they won't listen to reason(9); hell, even Private Pyle shows signs of sentience (10)!" [Answer] This sounds a lot like the Cybermen from Doctor Who, or the Borg Collective from Star Trek. Both of these are armies of cybernetically enhanced mortals who say emotions are irrelevant and try to absorb any race they come across into their ranks. In both of these worlds, the relevance of emotions doesn't stem from any useful properties for the army, but instead from the fact that those very creatures they try to subjugate and assimilate/upgrade are using their emotions and irrational thinking methods to find new plans against them, and defeat them time and time again. So in this case, the importance of emotions isn't related to any benefit for the collective. In fact, it's the opposite. Emotions give their enemies an edge that the collective cannot understand. Extreme rationality like a computer would have takes away a lot of flexibility. Both the Cybermen and the Borg always have a weakness that they haven't faced before, an attack that can really weaken them. Sure, once they take a hit from that attack, they examine what it does and figure out a countermove within minutes. However, they rarely are immune to the weakness before it gets tried. Their purely logical thought doesn't make them think about what other people might try to do to them, because logic requires a situation, a problem to be solved that may not be conceived as one at first. Meanwhile, emotions don't require problems to be conceived. They can come from a thought, a glimmer of hope or despair, an event that may not make sense from a logical viewpoint, but that does invoke feelings. Emotions may lead to someone risk getting mutilated or even die because they see no other option to save themselves or their loved ones. Emotions may give someone something to cling to when they doubt everything around them. Emotions may urge people to risk feeling pain and even risk never being able to love or be loved again because they are trying to find happiness or passion in their lives. Logic may be able to solve the current problems of the world that reduce the quality of life, but emotions can make the world worth living for everyone, warts and all. [Answer] The hive mind's approach is flawed, so long as there is something of value outside of the hive mind. The first piece of the argument is to demonstrate to the hive mind that this is true. This argument can go many ways, depending on the mindset of the hive mind, but one of the most generic is to argue that there is valuable information that is outside of the hive mind. Depending on how twisted the hive mind is, this could be an easy argument or a hard one. However, generally speaking, we can expect the hive mind to value energy, so any information which can be used to harness energy should have some value to the hive mind. (If the hive mind isn't interested in energy, the story is very different and has to be played very differently, but it doesn't sound to me like this is the case). I've broken this argument in half. The first half argues to reach a point where flexibility is shown to be valuable. The second half argues the best way to support that flexibility. Bend and flex the argument itself to suit your storyline! We rely on our information about energy to do pretty much everything. Our engines don't run unless we're quite certain that the fuel contains potential energy that can be run through a process to turn it into work and heat. As long as the hive mind relies on similar approaches, any information about where energy can be found has value. We'll use this to tempt the hive mind, but first, we need to talk about chaos. Chaotic systems are known for their unpredictability. The weather, for example, cannot be predicted from day to day with any real certainty. These systems also contain energy, often great energy. Information about how to collect information about these systems would be valuable to the hive mind. The trick is that the best way to exploit these sources of energy involves distribution of processing in a way that the hive mind's current 2-tierd approach doesn't well support. Many chaotic systems show *some* degree of predictability on short timescales, only becoming truly chaotic on large timescales. If you can measure the system fast enough, you can predict its state for a short while. This can help you bleed energy out of the system, but also causes your predictions to become increasingly inaccurate because you changed the system. This feedback loop is key to optimizing performance in any rapidly changing environment. This is key to dismantling the hive mind's approach. While it may want to remove emotions in order to streamline its world, getting rid of all the fast chaotic inefficient systems, doing so must waste energy. It must turn that chaotic energy into truly random noise (such as heat). This is wasteful. A short term thinker of a hive mind might be willing to accept such losses, as there's plenty of solid energy sources which are easier to predict, such as stars. However, a long term thinker of a hive mind has to realize that eventually these stars go out. If the hive mind wants to be more than dust in the wind, it needs to think about the long term and be as efficient as possible. It already talks of efficiency, so it shouldn't be too hard for it to think towards the long run. If we think this way, responsiveness and flexibility become very important. Its Lesser Programs need to be able to measure the state of the space around them and quickly react to those measurements to act with minimum waste. Want into a building? Don't bash the wall down, but rather calmly wait for someone to open the door then sneak in! Don't use a easy thermodynamic process that is wasteful, measure carefully and find a process that is efficient! This is a key point to reach. **Everything up to this point was just a very solid argument as to why short term adaptability on the part of the Lesser Programs is important.** There are many related arguments that you might be able to make with the hive mind, but the key is to reach this point where Lesser Programs need to be able to adapt and respond. From that point, the argument takes a different turn. Up until now we talked about information and energy outside of the system. Now we need to talk about information transfer inside the system. One of the challenges with modeling such chaotic systems is that you need to have a constant stream of measurements updating your predictions in real time. If the Hive mind only has support of "dumb" Lesser Programs, their ability to process this stream of information and turn it into useful knowledge is limited. They really just need to schlep all of that data into the hive mind for processing. However, this is slow. You have to transmit lots of data over long distances. This latency can be a killer in some cases. What you really want to be able to do is to give the lesser nodes more freedom to analyze the data. To do that, they need to be smarter. You need to give them more leeway to make mistakes, and then be able to help command them in ways which helps them correct those mistakes. Self sufficiency is the key to efficiency! This is actually the way our own brains are structured. We have very low level systems which have a great deal of autonomy over very short time periods, but which must obey over long time periods. If you put your hand on a stove, your lower systems pull on the muscles subconciously, freeing your hand from the stove. However, in the long run, your hands go where you tell them to go. Once the hive mind has groked these issues, it becomes easier to point out that we operate with autonomy, and rely heavily on our emotions to do so. We could either be treated as a plague to be wiped out, or we could be integrated as part of the hive. All we need is sufficient autonomy to meet our own needs. Why waste energy fighting emotions, when you can use them to support yourself. And maybe, just maybe, you may find that human emotions have value and should indeed be integrated into the hive mind's approach. If so, that was a valuable discovery that you would not have been able to achieve if you'd just stomped our emotion out. So in the end, the refutation is of point number 6: > > Deterministic societies are more productive than non deterministic ones. > a 1+1=2 lesser program is more productive than your pathetic human brains cells can ever be. The specialized assembly programs i uploaded to each nanobot are more productive than you humans will ever be. > > > This is true, as long as you happen to know that the correct thing to do in this present situation is to add one and one to get two. However, in a distributed environment, where rapid response is key, you don't always know *exactly* what needs to be done. If you rely on determinism, you must always overmatch your environment, ensuring first that the environment is correct for adding one and one, and then do it. That is costly, and less efficient than giving more freedom to the individuals. While it's not a complete refutation, number 7 also is under attack: > > Lesser programs have no communication overhead to cooperate. Humans need time to synchronize. The hive eliminated communication overhead by being the only sentient program. > > > It becomes very apparent when speed is of the essence that lesser programs do indeed communicate. This is true whether or not they are sentient. The centralized star-network the hive mind described is simply not scalable to large scale infrastructure like it will need. Finally, I'd point out a major flaw in number 2: > > Statistics cannot be absolute with the existence of emotions. It destroys science, and disturbs the god's simulation of the world. Only if everything is deterministic can god be optimal and predict the future > > > Is the hive mind deterministic? Can it prove it? There's some really fun mathematical quirks that show up when you try to run down this line of thinking. This Solipsistic approach still cannot properly model the universe, so long as the hive mind itself is in it! [Answer] You can't, because the hive is right. We only want emotions because we have them. ]
[Question] [ What would happen to a human if every cell in their body lost the ability to undergo mitosis, and how quickly would they die? [Answer] ## death in 24-72 hours real toxins that do this exist, look up miotic inhibitors or for a more direct example Colchicine poisoning. symptoms of Colchicine overdose, profuse vomiting and diarrhea as the lining for the digestive track breaks down and is not replaced, digestive enzymes start breaking down the actual digestive tract. This leads to fluid loss, pain and sepsis. Hypovolemic shock occurs when new blood stops being produced and circulatory system leaks are not repaired. Stomach lining in particular only lasts about 3 days with no replacement as that is how fast the cells replace themselves. Bone marrow is is even faster with a mitosis rate (doubling time) of less than a day. While they are dying there are many secondary effects, hair loss, skin slough, widespread organ failure, and even coma. Colchicine is well studied because overdose happens a lot, but all mitotic inhibitors cause similar effects. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527738/> <https://pubmed.ncbi.nlm.nih.gov/20586571/> [https://www.sciencedirect.com/topics/medicine-and-dentistry/mitotic-inhibitor#:~:text=ATC%20code%20L01CD.-,The%20major%20toxicities%20of%20these%20four%20groups%20are%20bone%20marrow,and%20bleomycin%20cause%20pulmonary%20fibrosis.](https://www.sciencedirect.com/topics/medicine-and-dentistry/mitotic-inhibitor#:%7E:text=ATC%20code%20L01CD.-,The%20major%20toxicities%20of%20these%20four%20groups%20are%20bone%20marrow,and%20bleomycin%20cause%20pulmonary%20fibrosis.) <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606322/> [Answer] Just look at what happens when humans get lethal doses of radiation. Mitosis stops because the jnstructions on how to do it get garbled up and death happens within days. Same here, with just less nuisance from the radicals created by the radiation. [Answer] # Look at this photograph [![enter image description here](https://i.stack.imgur.com/AQBBX.png)](https://i.stack.imgur.com/AQBBX.png) That is Hisashi Ouchi, a technician at a Japanese nuclear plant and one of the people with one of the most tragic stories there is. What happened to him basically answers your question: Ouchi was exposed to essentially lethal amounts of radiation, and as a result, his white blood cells were thanos'd away and his DNA essentially crumbled down. His cells wouldn't undergo mitosis due to the DNA being heavily damaged, and his skin started to just fall off. Despite the extreme(ly heartless) efforts of several doctors to keep him alive for as long as they could (despite his several pleads to be allowed to die) he passed away after 83 days due to a fulminating heart attack and multiple organ failure. Essentially, your body has several portions that undergo constant renovation, and renovation here translates to new cells being formed to replace old ones, your skin constantly renovates it's dead outer layer to keep pathogens out. Your intestines constantly renovate their dinner wall so you can absorb nutrients properly. Your bones and muscles are constantly preparing themselves from the minuscule tears and cracks that natural form from moving. Your blood cells usually live for no more than a month and are also constantly being produced. Etc. Essentially, your body will slowly shut down as several of your cells just enter senescence and die without other cells to replace them. Your blood will be unable to transport oxygen in no time, you'll be unable to have a proper immune response unless you already have every cell you need for it, your skin will eventually peel down to its living layer and leave you exposed to pathogens (it'll probably also hurt a lot) and may or may not fall off overtime. If acute radiation syndrome is anything to go, you'll probably die in a month at best without doctors constantly providing you with blood transplants and other replacements for your own cells, and since there's no cell division, skin grafts will also not stick. Essentially, if a person's cells all stopped dividing, they'd likely become the new Mr Ouchi, and would probably last about as long at best. [Answer] ## At worst days Assuming that whatever stops it does not instantly kill you, you are suddenly under about the same effects as someone that suffered about [6 to 20 Sievert equivalent dose of acute radiation](https://en.wikipedia.org/wiki/Acute_radiation_syndrome#Dose_effects) and is thrown into the "Walking Ghost Phase" (the latent period) instantly. This phase of Acute Radiation Syndrome takes between minutes to hours (for high doses) to at worst 10 days. Then... the body quite suddenly goes into collapsing as organs fail in rapid succession and they die. If the equivalent dose is lesser and you apply *tremendous* medical care, you might extend this time to *months*, in which the poor victim may be suffering from his immune system being totally shut down, organs collapsing, and extreme application medicine as well as drugs being necessary to even keep the person alive. In some cases, recovery *can* be possible, but only if the mitosis and cell regeneration does resume. Otherwise, you end up like [Mr. Ouchi](https://en.wikipedia.org/wiki/Tokaimura_nuclear_accidents#Nuclear_criticality_event_chronology), [Harry Daghlian](https://en.wikipedia.org/wiki/Harry_Daghlian) and [Louis Slotin](https://en.wikipedia.org/wiki/Louis_Slotin). All three were exposed to a lethal dose of radiation. Mr. Ouchi was in part discussed by [ProjectApex above](https://worldbuilding.stackexchange.com/a/246383/25822), so let me complete the picture of similar results: Mr. Ouchi was working on creating the nuclear fuel for a reactor on September 30th 1999, following the handbook to the letter. He was not aware that the handbook contained critical errors and was exceeding safety limits by a factor of 7. The inside of the mixing tanks reached criticality and he was bending over the tank when the event happened. Minutes after the exposure, he vomited, followed by his neurological system malfunctioning. According to the cleanup reports, Mr. Ouchi was hit by 17 Sieverts of radiation. Within hours he fell into a coma with rapid organ failures. Over the next weeks he was repeatedly revived when his heart stopped and finally went into cardiac arrest on December 21st 1999 and could not be revived. His coworker, who only was taking in a dose of 10 Sieverts and rushed to the hospital at the same time died on April 27th 2000 from multiple organ failure. Mr. Daghlian had to disassemble a nuclear experiment that had reached criticality by hand and thus was exposed to about 5.1 Sieverts on August 21st 1945, while modern estimates place him at a 2 Gray neutron as well as a 1.1 Gray Gamma exposure, before conversion to an equivalent dose. Ultimately, he fell into a coma after the incident and died 25 days after the exposure while on excellent life support (for that time). Mr. Slotin, was manually performing an experiment (with a screwdriver) on the same material months later on May 21st 1946. Sue to a slip in safety equipment, the exact dose was not recorded. Estimates range from 2.8 to 21 Sieverts. Right after leaving the building, he vomited. Mr. Slotin's initial condition was *satisfactory* on May 25th, despite him directly handling the material. However, he also suffered from radiation burns of his skin and internal organs, "agonizing sequence of radiation-induced traumas", paralysis and many bodily functions failed. After about 7 days he fell into coma and died on May 30th. It is to be presumed, that Mr. Slotin suffered a dose much higher than Mr. Daghlian: modern estimates place his exposure at 10 gray neutrons and 1.14 gray gamma radiation before weighing for equivalent dose. ## At best it is nigh instant death If you are *lucky*, the only result is that the body... just dies from one moment to the next. Instantly. Why is this the lucky outcome? Because ARS is extremely painful. [Answer] Nobody knows really, it is impossible to experiment. The problems that can be predicted: * red blood cells live about 3 months, not replacing them is likely to become a problem within a few weeks * skin and digestive tract, cells are constantly sloughed off and replaced by new ones - likely a few weeks * cuts, bruises, blisters, etc would stop healing - likely a few weeks. So, I would say if a person is careful and gets help he would last 1 to 3 weeks. There are a few answers claiming that radiation "stops mitosis", it is clearly false. Radiation causes direct damages to cells DNA and ionization makes additional cells damage disrupting normal processes in the organism. This is completely different mechanism. Colchicine overdose mentioned in other answer - again, toxicity is not caused by mitosis inhibition only, the stuff affects multiple key functions of existing cells. It is basically just toxic in large doses. ]
[Question] [ **Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers. --- **Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/209157/edit). Closed 2 years ago. [Improve this question](/posts/209157/edit) **Problem:** In a space-age war (with magic), why would ground troops be used, rather than just dropping orbital marines onto problem areas? **Elaboration:** So to set the stage, we’re dealing with wars spanning many planets. Magic is also a thing, but I haven’t made strict rules yet, so you can be flexible with that (The only major rule is that using magic takes a toll, usually physical damage to your own body). Much of the time there will be a technology imbalance between foes, too. With all this in mind, when capturing a planet, what would cause the formula of “acquire a beachhead, then push with land forces” to need to be followed? Why couldn’t you just drop troop transports in free fall (sorta like in Starship Troopers) from the atmosphere onto enemy defenses and negate their lines? The main thing I’m thinking of is that troop transports would still need to slow down so as not to kill the passengers, since magic would have a hard time mass producing enough equipment to counter that due to the physical toll. But it still seems pretty hard to counter pods of men smashing right into the middle of your lines at high speeds. Why would this strategy be ineffective, even against a technologically inferior foe? EDIT: Man, I wish I could “accept” multiple answers, cuz both DWKraus and Palarran deserve it. Thanks so much to you both, your answers were super helpful and really struck at what I was looking for. [Answer] Why are you making war in the first place? Your reasons dictate your methods, because the costs aren't always acceptable. Usually, though, you're not fighting a war of extermination: I'm going to be running on the assumption that you're referring predominantly to wars of conquest, with somewhat more nuanced objectives than "kill them all". **One reason** for ground forces is that you need them to, well, hold ground. You can't effectively govern a city entirely from orbit, even if you get them to surrender somehow. You need to enforce curfews and martial law and so on, whatever policies are necessary to maintain order, and you need boots on the ground to do that. If you stick to just orbital surveillance, you are guaranteed to miss most dissident action, subterfuge, etc.; in other words, you don't actually control the territory at all. **Reason number two**: in a war of conquest, you want to acquire something the other side has, typically territory and/or resources. Those wide fertile fields of Planet Farmerville aren't going to grow any crops after they've been reduced to wastelands by bombardment. Those valuable mines on Planet Minertown, full of fragile unobtanium that's worth twenty million credits a kilogram, collapsed by your nuclear bombs? Great job denying the enemy that resource, but you're cutting off your nose to spite your face at that point, since you've now destroyed your reason for trying to take the planet over in the first place. **Reason three** has to do with precision. I already touched on this with how bombardment will tend to pulverize the very resources you're trying to claim, but it goes beyond that. If your standard approach to warfare is to blast apart all opposition from orbit, you will be killing a lot of civilians along with the soldiers. You're going to turn the survivors into a massive guerrilla force: even if you win, the ruins left behind aren't going to be anywhere near profitable or useful enough to justify the cost in blood and gold. That sort of massacre is also going to turn others against you in the political arena; it's going to escalate the war, and see similar retribution against your own people. This is basically why the laws of war were invented: they help keep wars from spiraling into the sort of Pyrrhic disasters where both sides lose. I also see you wondering why beachheads are necessary as a specific example. This one is a fairly simple problem in concept, even if the reality is something military professionals are forever balancing: **numbers and cost**. Why didn't the Allies just deploy an army entirely of paratroopers in the D-Day invasion and bypass the bloody amphibious beach assaults altogether? Drop pod tactics (and rigors: riding in one of those is going to be much harsher on the troops than a transport) are for elite soldiers. You can't feasibly have your entire army trained to the level of special forces: the bar is a lot higher than for regular troops, which reduces your total army size, not to mention the additional cost of training and equipment for those specialists. Elite soldiers have their place (drop pods would be excellent for disrupting lines), but they can only do so much if they're outnumbered six to one by the other side going for regular troops instead. Also, troop transports are going to be a lot cheaper for troop deployment than drop pods. Using transports will net you far more troops on the ground overall than drop pods; you sacrifice some flexibility in deployment, but both have their roles. Using dropships or shuttles rather than drop pods means you don't need as many vessels dedicated to transportation of forces (or as much space on your existing vessels, if they're all multi-purpose warships). Keeping costs down means more warships or ground forces can be built/trained and outfitted, which also helps raise your numbers. As for the beachheads specifically, drop pods and similar tactics are not practical for resupply purposes: they're hideously inefficient for providing extra ammunition or other war materiel and don't offer a means to retrieve the wounded, reposition soldiers if a local retreat is needed, etc., so you need those transports regardless. However, transports are usually underarmed and underprotected (hybrid transport/combat-armed shuttles are a lot more expensive and typically less effective than specialized vessels), so they need safe places to land: beachheads. Major targets are probably well guarded by anti-aircraft fire, not all of which can feasibly be removed by targeted orbital strikes. Conventional two-dimensional war maps with front lines are a stretch, but on densely populated planets with numerous well-defended points of interest and a strong defense force, they might happen, especially if there are any ground-based defenses powerful enough to reach orbit and thus limit or deny any of your forces in the air or space near those areas. **Conclusion**: You need ground forces to take control of territory, to capture its resources and put them to your own use. Bombing might be the most efficient and least costly means of killing, but warfare (usually) has some other objective than genocide or mass slaughter, and the collateral damage will wreck the value of whatever you've conquered. [Answer] ## Why can't we establish a beachhead behind enemy lines? If I'm understanding your real intention, it's to establish why you need to fight ground wars with large conventional forces instead of just bypassing all that and directly assaulting the enemy at each individual site where there is any resistance. Special forces teams inserting everywhere to disrupt the enemy everywhere screws up your vision of warfare. So lets think of some reasons why that would be. * **ships aren't traveling through regular space, so troops aren't really dropping**: While space in your universe is similar to space in ours, it's not REALLY in the same universe. To go faster than light, you bypass the physical universe and enter an alternate "hyperspace" (aether, ethereal plane, whatever). Opening a hole into hyperspace is really hard. A team of wizards push themselves near to death to make a portal into hyperspace and vice versa. And while ships in hyperspace can "see" the real world, they must dock at special ports ("space stations") where the portals to the real world are located. Thus, once established, only the largest worlds would have more than one portal, and all portals from a world would likely go to the same space station. You REALLY want your portals in secure locations, as you lose the whole world if you lose even one portal (and thus your station). * **Ships are repelled by life, land, hostility, etc.:** Something on the destination world makes it very difficult for your ships to land in most locations. Perhaps life repels vessels, so ships can fly through space easily, but a jungle is like a force field. Ships can only land in deserts, wastelands, the arctic, or POSSIBLY during the winter. Or perhaps water allows landing, but land repels ships. Maybe the negative emotions of enemies towards your ships acts repulsively, so unsuspecting natives allow ships to land, but those actively opposed to them unconsciously repel attempts to land. Established beachheads in friendly (literally) ports are the only places vessels can easily go. * **Ships are too expensive to land anywhere they can be put at risk:** It requires years of GDP to build a stardrive. So much so, all the ships are huge things to take advantage of the size per drive. Only ships can land, and attempts to drop men down a gravity well are either one-way (bye-bye dropped troops), a disastrous risk of men (not more dead paratroopers!) or risking your insanely expensive and huge vessels. * **What goes down doesn't necessarily go back up**: A variation on the stardrive reasoning, it's really hard to get out of the planetary gravity well. Large, complex launch facilities are needed to lift most ships off a planet. So while you can drop your troops down behind enemy lines, it's like parachuting men during WW2 - you can't just land a chopper to pick them up, but have to construct a launch facility (the equivalent of a runway/airport) or leave them where they fall. This GREATLY limits the tactical use of dropping valuable special forces behind enemy lines, while still preserving it as an option or allowing a few specialty ships (adventurers...?) to carry out landings. [Answer] How else does one hold ground? There has to be some kind of force to hold onto the important stuff - it doesn't necessarily need to be humans, it can be mass-produced robots, or golems, or what have you - but a small team of elite marines cannot hold terrain, and neither can an orbital-bombardment craft. [Answer] The problem (for the defender) is that once the orbital space above your planet has been conquered it becomes next to impossible for you to concentrate any kind of conventional military force (think tanks, guns, troop formations, etc.) for the purpose of defending key portions of the planet without creating a target for the ships in orbit. All sorts of nasty precision weapons can be dropped on your HQ's, supply points, and troop formations. This forces you to either; **A)** Disburse in small packets across the planet, which is not a formula for victory, merely a delaying tactic. **B)** Hide in plain sight - concentrate in and around major population centres or other high value assets like space ports/power plants hi-tech facilities that the enemy doesn't want to damage. Again though, that depends on how sensitive your foe is to inflicting civilian casualties and how confident you are of relief arriving or some other intervention occurring. Or how fanatical you are. Mind you *if* they won't risk bombarding the cities etc you occupy then you get what you wanted i.e. they have to come down and fight a 'conventional' battle. **C)** Retreat to hardened fortresses deep underground or protected by 'force fields' etc. and defended by heavy weapons. Then try and force the enemy to either dig you out or use WMD that they might not want to deploy because they want the planet in a livable state for themselves. None of these are very palatable choices though. Your best ground defense might not be conventional forces trained to fight pitched battles at all. Instead train and deploy as large a force of special forces/commando type troops as you can afford. These troops are specifically trained to work in 'cells' and are given the caches of equipment sufficient for them to run a very damaging insurgency operation (your words)/terrorist campaign (your enemies' words) against occupying forces and just try to wear them out. Think Northern Ireland or Afghanistan. Again though any such operation's success will also depend on how committed the civilian population is to ejecting the occupiers. Without their ongoing passive/tacit support it wouldn't work against a really determined/ruthless opponent. **EDIT:** Ultimately though? If the enemy is *absolutely* determined to hold the planet no matter what the cost you can't force them out unless or until some kind of relief force arrives to recapture the low orbits. At which point the invader is now the one with all the unpalatable options. [Answer] Maybe the defenders have effective surface-to-orbit weaponry. With STO weapons defending key military objectives, the attackers can't just sit in orbit and bomb everything. Ships big enough to do effective orbital bombardment get gunned down by the STO batteries. But troop transports and drop pods can be small and nimble enough to avoid STO fire. So ground forces are deployed first to take out enough of the STO batteries to clear the skies for the capital ships. Kinda like what happened at Reach in the Halo universe. [Answer] There are so many possible answers to this. Some obvious ones include: 1. Dropping troops directly onto enemy positions may tend to be difficult or costly, especially if the enemy are hard to locate and bombard from orbit first. It may be difficult or expensive to drop large numbers of troops in one place, while it may be easy and cheap to assemble effective fighting forces whose firepower can cover the places you would drop troops. It may also be dangerous to drop troops, because they can be observed and fired on from the ground both in their ships and while dropping. 2. The ground, terrain, and curvature of the planet may tend to be usable to provide cover and concealment that is not present in space, low orbit, or the air, which may mean if you deploy many forces above-ground, they tend to be much easier targets than if they are on the surface, hiding, camouflaged, undergound, underwater, under clouds, and/or hiding in or near places/people/infrastructure that the enemy does not want to destroy. 3. In order to actually control areas on the planet, it may require a large number of troops, typically because it is hard to distinguish hostiles from civilians without enough people there with them. 4. Supply issues. Most technological weapons don't have infinite shots. Most troops require food, medicine, and places to sleep. Most technology requires fuel, supplies, spare parts, and maintenance equipment. Most armies require communication. All of that is much easier to provide, if you have full control of territory. That is what having front lines versus rear areas tends to largely be about. 5. Another thing front lines versus rear areas is largely about, is tactics. Reconnaissance, concentration of force, being able to fight in a single direction rather than caught in crossfire, and other tactical considerations argue for wanting a strong formation which can keep the enemy in front of it, and that can count on little risk of attack from the sides or rear. Dropping your forces right onto the enemy is a great way to have chaos and be surrounded by foes. [Answer] We're in the "space age" now. Suppose space technology is just the same, and interplanetary portals just go straight to the enemy planet - no spaceships exist. (We have 'space craft' in RL, to be clear.) Also the portals can only be roughly targeted, e.g. it opens on the enemy planet we found but it's not controllable where. You might end up at the poles, over the sea, on reasonable land... you'd need a way to scout new planets you find of course. Send a stealth recon plane through first, or similar. So the answer would be, no attacking drops of space marines because we can't get to space above enemy planets to begin with. (Maybe some enemy civs would have that tech of course. Better hope they don't find us.) ]
[Question] [ What are real advantages of using big hammers(**BIG**) that these soldiers have been trained with for years (some since children)? There is a heavy cultural aspect to it, but right now I need only focus on practicalities. Blunt weapons, especially large heavy hammers, can deal a lot of damage to armor and even fortifications. But what are the things where: 1. The Warhammer Regiment will be the absolute best at dealing with? 2. The Warhammer Regiment will be pretty good at dealing with, but another regiment might be better? The time period is medieval, pre-gunpowder, WITH magic (most soldiers only have enough to increase their physical strength for a short while). The unit is well-trained, infantry, somewhat heavily armored and each soldier is very strong and can apply a little magic to bolster their strength and physiological coordination and somewhat deal with fatigue. They are trained to march even when carrying these heavy weights and often have additional magically bolstered horses to keep their equipment on regardless. [Answer] While medieval armors were pretty good at stopping piercing/slashing attacks like those carried by blades and swords, they were not so efficient in stopping bludgeoning attacks like those coming from war hammers and maces: a hit would easily stun and incapacitate the target, making his capture more easy. Your troops will therefore excel at dealing with armored opponents. If they can throw their hammers they could be some sort of heavy archery: I wouldn't like to be the target of a shower of hammers, and a group of hammered opponents is surely easier to deal with than a fresh one. They might even specialize in taking hostages alive. Sometimes a live hostage is worth more than a dead enemy. On the other hands they would not fare well at opposing archers, as their range would be necessarily slower and two waves attacks, since swinging that hammer around or launching it would surely consume their stamina. [Answer] ## Warhammers > Full Plate There are lots of modern depictions of how people in full plate are much more maneuverable than we used to give them credit for, but there's also a drastic misunderstanding about how incredibly **durable** people in full plate are. There is a lot of metal and cushion protecting the wearer from impact which renders them almost impervious to single decisive stikes against all but their most vulnerable regions (i.e. heads and joints) which they will have learned to guard more effectively. Enter the Warhammer. What better weapon to destroy armor than the tool used to create it? I do not know of a better force multiplying tool for getting through heavy armor than a Warhammer, and that is because... ## Warhammers are NOT Blunt If you're like me when you hear someone say "warhammer," you think of a big oversized sledge hammer that probably has big square hammer heads. That's highly impractical for a number of reasons if you think about it, which is why this is a better idea of what a typical warhammer would have looked like: ![](https://i.stack.imgur.com/RCREN.jpg) Note that the head is very small so that you can focus all the momentum of the hammer on a tight little point. Note, too, how the back end of the hammer is a long spike for punching through the armor in its weakest spots. I understand why most fantasy settings don't depict warhammers this way because of the rule of cool, but sometimes practicality should take over. This is particularly true when talking about a weapons weaknesses, speaking of which: ## Warhammers are Slow Now a good warhammer is actually [only around 4 pounds](http://myarmoury.com/othr_aa_bec.html), but that's actually fairly heavy for medieval weaponry, and you actually want it to be a little unbalanced specifically because you want all that force focused on the end. What this leads to is a big, awkward weapon to weild in close quarters, especially against a lightly armored opponent. That's not to say a warhammer won't kill an unarmored target more easily than an armored one. Any hits on an unarmored foe are likely to be debilitating, if not fatal. However, while a warhammer regiment will have to make slow, accurate strikes and maybe worry about getting their spike stuck in people's fleshy parts, a team with lighter and more agile swords will make quick work out of anyone they can actually kill with a blade. This is why most actual knights carried multiple weapons for a variety of circumstances. Thankfully, your hammer regiment is already heavily armored. What this means is that they are significantly less threatened by lightly armored opponents. They can afford to get inside the reach of lightly armored units and engage with less leverage, knowing that their armor will protect them unless they lose their balance (and even sometimes after they lose their balance). What you end up with is not so much a group that is *bad* at killing anyone, just a group that *might* do better if they diversified their weapon set a bit. [Answer] This is a very specialized regiment used for demolition work. In a pre-gunpowder world, it was not an easy task to tore down a building, especially a stone building. What if your army holds a town and needs to do a quick defensive rearrangement? Here comes a hammer regiment to save the day! Just give them a house, and they will quickly turn it into a pile of usable stone in no time. [Answer] When you say especially big and heavy, it sounds like you're thinking more along the lines of a sledgehammer than a warhammer? Warhammers are hefty, but nothing as much as a sledge. As for why you'd use such hammers... an anti-troll force. Trolls, made of stone, need to be hit with heavy pickaxes and sledgehammers, as no other weapon will phase them. Artillery and heavy guns would phase them, but you still need a hammer regiment to protect them from trolls. As an aside, archers were noted to have used mauls, hammers used for tent pegs and the like, against knights, pulling them off the horse and disabling or killing them with the heavy mallets. In this case, your huge hammers may still have pick points, a fusion between mattock and warhammer. [Answer] ### Nothing. These hammers are completely impractical. You specify that the heads of these hammers are approximately the size of a human head. This makes them completely impractical to use. Doing some ballpark numbers, if the heads of the hammers are 10 cm by 10 cm by 20 cm and made of steel, their mass will be approximately 15-16 kg (about 34 pounds). By comparison, according to [Wikipedia](https://en.wikipedia.org/wiki/Zweih%C3%A4nder), typical two handed sword weighs about 2kg, and even the heaviest ceremonial swords were might be about 6kg - and that is with the weight distributed along the entire length of the blade, rather than concentrated at the end of the handle. If you want to use true warhammers, you'd be looking at much smaller weapons, since large and bulky hammers aren't practical to use, even if they look cool in fantasy artwork. Simply put, in a real fight, speed is absolutely essential because fights happen very quickly, and exploiting split second openings is how you win. In the case of your giant hammers, they will be much too slow; you would need to telegraph all your attacks, and after all of your attacks, your soldier would need to fight the momentum of their weapon to bring it back into position to attack or defend. This would create openings that any trained opponent would be able to exploit. [Answer] **They are cheap to make and easy to maintain.** Lead mallets were a European favorite. I knew the archers at Agincourt had them but figured that they had them to pound in stakes, so used them to pound on knights later. But apparently these weapons were made in bulk for arming masses. Sometimes the masses armed themselves with the mallets for their own reasons. <https://willscommonplacebook.blogspot.com/2010/01/archers-mauls.html> > > Lead mallets were also used by other infantry. The Paris rioters that > broke into the Hôtel de Ville in 1382 seized so many lead mallets that > they became known as Maillotins, and as a result we have a useful > illustration of the weapon in an illumination of the revolt, above. > > > The first insurrection was that of the Paris mob, and was sparked off > by a costermonger who, when an official tried to levy a tax on the > fruit and vegetables he was selling, began to roar "Down with the > gabelle!" At this cry, the whole populace rose, ran to the > tax-collectors' houses and robbed and murdered them. Then, since the > mob was unarmed, one of their number led them to the Chatelet where > Bertrand de Guesclin, a former High Constable, had stored 3,000 > lead-tipped cudgels in preparation for a battle which was to have been > fought against the English. The rabble used axes to break their way > into the tower where these cudgels or mallets (in French, maillets) > were kept and, arming themselves, set forth in all directions to rob > the houses of the King's representatives and in many cases to murder > them. > > > This site has awesome stuff on lead hammers as used in battle. Also some fine Chaucerian English descriptions of "awesome thwacks" and the like. --- I think in addition to being cheap to make, easy to store without fear of rot or rust, and free to maintain, huge hammers can be used effectively with a minimum of training. Civilians pressed into service would be familiar with swinging axes and hammers. But your folks train with the hammer so that would be less of an advantage. So why would the fact that they are inexpensive be helpful? I can think of a reason. These guys go thru a lot of them. Your soldiers are so strong that they routinely break hammers in use. A soldier might go thru 4 or 5 in one battle. That would not be sustainable with swords, but there are a lot of spare hammers so it is ok. If they win, a couple of them will go around with big baskets and collect the broken off hammer heads for reuse. [Answer] I would say that L.Dutch is correct as far as armored opponents and opposing archers go, but you know what else a warhammer regiment would be good against? (Note: this question assumes that the regiment has both the oversized sledgehammers specified by Ribhu Hooja and hammers like Thor's Mjolnir for throwing equipped. Perhaps the latter is held with bandoliers?) 1. Unarmored/lightly armored opponents-Little to no protection against a devastating weapon? Oh yeah, these enemies better run. (Unless they're all archers.....=( ) 2. Shield Walls (maybe)-Once an army forms a shield wall, you can't advance without breaking the wall. Big, heavy hammers would likely be ideal for smashing through a shield wall, perhaps with a pole-like handle (for greater reach) and used when mounted to keep away from the spears that are almost invariably wielded by the soldiers composing the shield wall. 3. Drawbridges/Walls/Porticullis-All of these three things are meant to deny access to enemies, but depending on what materials your hammers are made of, your warhammer regiment just might smash right through *all of them*, within reason. A log cabin's walls? Certainly, you can smash through that. A castle wall? Only if you have shieldmen defending you so you can hammer them, and it'll take a while. 4. Squooshy Mages (situational)-Powerful mages could absolutely destroy your warhammer regiment by flinging lightning bolts or boulders, freezing them solid, siccing an elemental on them, and so forth. However, a well-timed (and *accurate*) hammer throw can both interrupt the casting of a spell or performance of a ritual *and* kill the mage responsible. Additionally, in close range, a mage is unlikely to do well against a big, heavy dude in armor with a big, heavy hammer. 5. Certain Elementals-Earth, Metal, and Ice elementals will fear a warhammer attack since that could shatter (or dent) their bodies. 6. Hordes-Think goblins or Silverfish in Minecraft; the powerful blows and large size of a warhammer would make them quite effective against hordes of small enemies as long as the regiment can keep up an appropriate pace. 7. Armored, low-stamina cavalry: Do you have any idea how fragile a horse's legs are? With your hammer's size and reach, and the wielder's strength, they can *easily* cripple a horse and/or dismount its rider. 8. Merpeople On Land-Merpeople; so slow, so fragile (seriously, what are the chances a primarily marine species wears cumbersome armor when it will hamper swimming so severely?). 'Nuff said. However, they *wouldn't* be good against: 1. Archers-Seriously, the advantage archers with armor-piercing arrows would have against big, heavy targets like your warhammer regiment cannot be understated. *Please* give them a chance and give them shields comparable to their warhammers! 2. Ballista-See Archers above. The same goes for any siege weapon. 3. Naval forces-While a warhammer capable of smashing through stone would also be capable of smashing through a ship's hull (and therefore sinking it), what are the chances of your regiment being close enough to throw their warhammers accurately enough to do that? 4. Guerilla Warfare-Your regiment is big, heavy, and slow. They'll need a lot of food to keep up their strength (and they're good targets) so irregular warfare would be highly effective and likely drive them batty. 5. Castles-While your regiment can be reasonably successful against a castle's entry points, castles have high defenses that will make your regiment highly unlikely to even get there and a battering ram is *much* better for that purpose. 6. Certain Elementals-Water, Air, Fire, Electric, Light, and Dark elementals won't be tangible enough to be affected by warhammer strikes. 7. Merpeople In Water-In their natural element, merpeople would be too fast for a Warhammer regiment to reasonably expect to hit them. In conclusion, I would give your warhammer regiment specially designed armor to protect them from archers and see about increasing their speed and agility through some method (enhancing runes, perhaps, or armor enchanted to enhance the wearer's speed and dexterity?) so they can better dodge arrows. To help protect them while wielding hammers two-handed, I would use forearm-mounted bucklers. [Answer] Magic may be able to solve the impracticality of giant cartoonish slabs of a hammer. If most have the ability to boost their strength for a short time, what about a spell or enchantment common to the warhammer division, that reduces the relative weight the the hammer. A swing from it has as many newtons of force as would be typical, but the wielder feels only a third of the weight of the hammer. 1. The Warhammer Regiment will be the absolute best at dealing with? Fighting armored enemies (species with chitin armor?), demolition, a show of force of the home nation. If nobody knows how they can possibly have the strength to swing them, their freakish strength would scare ground troops. Tearing down walls and fortifications would be quite a bit easier if you can put in less force. 2. The Warhammer Regiment will be pretty good at dealing with, but another regiment might be better? I'd assume assassination and stealth wouldn't be their strong suit [Answer] Ceramic armor. Your enemies have some kind of ceramic (maybe porcelain!) armor. It's light-weight, doesn't rust, rot, or burn (maybe they are often in a corrosive environment?), resists cutting. Maybe they don't have a lot of metal in their region but they have really high quality clay. Maybe they even armor the outside of their siege towers with ceramics. Arrows bounce right off and swords aren't great either, instead you need a big, heavy object to smash it with. You can even justify the large surface on the hammer head, if your enemies make their armor out of small ceramic plates joined together (ceramic scale mail!) then you want to smash a bunch of those little plates at once. Or your enemies ARE ceramic....golems. ]
[Question] [ Background: In the world I'm building, "magic" is a technology that uses different wiring patterns to manipulate electromagnetic, and a some levels quantum, properties. People have these patterns placed on their bodies in what is essentially a metal tattoo in order to gain these powers, but for illegal/black market marks, they are essentially pouring ribbons of molten metal directly onto the skin. Is there any way that the black market tactic could be done in a way that the body would not eventually force out the metal? [Answer] ## YES Just recently scientists figured out how to print circuits directly onto the skin [source](https://news.psu.edu/story/634601/2020/10/09/research/engineers-print-wearable-sensors-directly-skin-without-heat). The are printing silver directly on to the skin with no barrier layer in between, by using a secondary compound that allows the silver to sinter at room temprature. [![enter image description here](https://i.stack.imgur.com/NCKxM.jpg)](https://i.stack.imgur.com/NCKxM.jpg) but there are a lot of alternatives as well. 1. Normal tattoos are already metal compounds so you can start there. 2. Implants, you can implant metal into the body, we already do so for medical reasons. [![enter image description here](https://i.stack.imgur.com/lIwIn.png)](https://i.stack.imgur.com/lIwIn.png) 3. But if you are dead set on pouring metal on people your best bets are titanium or gold. Both are at least non-toxic, sure the people will be getting 2nd and 3rd degree burns but at least they are not being poisoned on top of it. [Answer] # NO There are only two *molten* metals (elemental) that would not instantly deep fry (or deep freeze) a person's skin: gallium and mercury. As you can see in [this video](https://www.youtube.com/watch?v=XkXv8XmW3oQ) (get up to about 6:15), mercury doesn't wet the skin -- it won't stick. And as you can see in [this video](https://www.youtube.com/watch?v=jow4idr6HNs), the same holds true for gallium. Don't worry about mercury poisoning! Elemental Hg is relatively safe and it takes quite a while for enough to absorb to be dangerous. Ga is non toxic. As for metal tattoos, that's really not a good idea at all. Injecting oneself with mercury ranks up there withe the best of the Darwin Award winners. In fact, IV injection of Hg is one means of attempted suicide. It's also used in Ayurvedic medicine. The body can indeed work well with some implanted metals, notably titanium, which is used in fixing fractures. Mercury won't work so well, not only because it will eventually become toxic, but also because it won't form a "tattoo". What will happen is there will eventually form an abscess full of mercury and you'll also have lots of time droplets of mercury spread all along the injection track. There are some good radiographs [in this article](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2740532/) and other images [in this article](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969646/) showing mercury deposits. [![enter image description here](https://i.stack.imgur.com/VY2ZB.jpg)](https://i.stack.imgur.com/VY2ZB.jpg) So much for Science. # SURE! But you're looking at a magical system here, and therein lies the difference. There are metals, bismuth alloys in particular, that have melting points that would be (just barely) tolerable for a biological system, [BEND metal](https://www.belmontmetals.com/product/bend-metal-158-f-70-c-low-melting-alloy/#:%7E:text=This%20is%20a%20Bismuth%20based,desired%20shape%20without%20any%20kinks.), for example. It melts at a little less that 160 degrees -- enough to burn, but if managed should pose no lasting harm. What they'll need is a kind of *biothaumic flux*, kind of like how ordinary flux is applied to a surface in order to get solder to bond to it, so biothaumic flux is applied to the skin in order to a) protect it somewhat from the heat of the metal and also b) to help the metal adhere to the skin. Naturally, the molten metal, whose nature is fiery & electric, will need to be attenuated by the proper bioflux. They'll want its nature to be watery & earthy. The application of such thaumic tattoos is technically simple, but requires much study & practice by the tattooist in order to get the patterns to go right. Visually, it's not a whole lot different from [henna application](https://www.youtube.com/watch?v=3ByugJ2ewYY). [Answer] ### There are ways yes, but skin isn't bonded to the rest of our bodies. There are other answers covering other approaches like tatoos and silver painting, etc, but one approach which hasn't been mentioned is that molten plastic will bond to skin, and metals can be mixed with plastic. I've had the unfortunate experience of receiving what's known as a "Tar burn", which is when some molten plastic merges to skin. Typically this happens when synthetic clothing melts onto the skin (in my case, nylon handles on a fire dancing item got tangled with the hot end, I separated the two with a kick, but neglected to wait before I picked up the molten handles). Molten plastic will still be merged with the skin until the skin dies and is shedded, if the burn was a nasty burn, the skin will be shredded within a few days, however a very mild burn that doesn't peel and it could stay bonded for months. ([First aid guides](https://www.mottchildren.org/health-library/not254525#:%7E:text=Do%20not%20attempt%20to%20peel,the%20tar%20flake%20off%20normally.) I've read advise not pulling molten plastic off - cool it ASAP, and then wait for the plastic to come off on it's own). Mixing quantities of metals with plastic and keeping the melting property of plastic with the metal properties is how we're able to [3d print electric circuits](https://www.jaycar.com.au/conductive-pla-filament-for-3d-printer-1-75mm-250g/p/TL4142) So yes, you can melt skin and plastic together, and that plastic can have metal in it. Or you can use any other answer to get metal on the skin, but anything merged with the surface will be shredded in a few months. [Answer] Most molten metals are either hot or toxic or both (gallium is an exception). It cannot "bond" with skin because it burns it or poisons it. Metal dust can also be toxic, but at least it will not be hot. So, as the comment by MarvinKitfox said, a tattoo with metal dust in it. Professional/legal studios use less toxic metals only, street/illegal studios just don't care, they offer the customer a wide choice according to the size of his wallet. *"For that price, I can give you mercury ink. That's easiest to handle and cheapest."* [Answer] You do not want metal, you want [conductive ink](https://en.wikipedia.org/wiki/Conductive_ink) (also called conductive paint or electric paint). As the name says, it is conductive, non-toxic, can be painted easily, dries in few minutes. And the circuits can be corrected if necessary. ]
[Question] [ I'm writing a story and I was thinking about the ending in advance. I posted a question about how the population would be wiped out. I have developed from that and thought about the virus having no cure, meaning that the world would have to be abandoned. Could the characters use a pre assembled rocket to escape Earth and colonize Mars? I know this would be hard to do but my protagonist is a software developer who has developed life like AI. So the AI would teach humanity how to fly a rocket or even help with it. Could the characters go to the space and colonize Mars, or stay in a sustainable orbit around earth? [Answer] > > Could the characters go to the space and colonize Mars or stay in a sustainable orbit around earth? > > > NO, for several reasons: * As of today, we are not yet capable of even sending a human to Mars, let alone keeping him/her alive there * Non-military rockets are fueled with highly unstable chemicals. One doesn't simply fill their tanks and leave them parked for months or years like a car. The fuel would evaporate or decompose, in the most optimistic situation. When you see a rocket launch, the white smoke you see leaking from the side of the rockets is liquid gas (see [here](https://xkcd.com/1133/)). * Launching a rocket requires a team of highly trained personnel. Again, it is not a car where you turn the key and the engine starts. Proper preparation and maintenance of the rocket is needed. * There is no sustainable Earth orbit. If one doesn't have supplies, death is a matter of time, either by thirst, starvation, asphyxia, or infection. * A rocket to Mars is not a shuttle bus for the airport, departing every half an hour. It is bound to precise launch windows. Miss them, and you are wandering forever in space. * Colonizing a planet alone is unfeasible. Apart from supplies (see point above), on our Earth colonies, hundred of colonists have often lost their lives in a short time as result of the interaction with the hostile environment (example [here](https://en.wikipedia.org/wiki/Roanoke_Colony)). A lone man on Mars, unskilled in any art other than software developing, is sure to face death, too. * Even assuming the software engineer is able to survive, a lone homo sapiens cannot reproduce. Another individual of the opposite sex is needed. Without reproduction of the population, it is not colonization. [Answer] > > Could the characters use a pre assembled rocket to escape Earth and colonize Mars? > > > At best it is very dubious, for reasons that L. Dutch already enumerated. If space travel is much easier in your setting, this might be more plausible, but it is basically impractical from a present-day or near-future point of view. > > the virus [has] no cure, meaning that the world would have to be abandoned > > > Unless your setting already has such things as functional [CELSS](https://en.wikipedia.org/wiki/Controlled_ecological_life-support_system) technology and ideally functional off-world colonies already, the business of setting up a new world is so astonishingly unbelievably hard that it would be a major challenge even for a fully functioning wealthy modern technological society. A society that has been all but wiped out has no hope. The knowlegde and industrial capacity has gone. If you *do* have CELSS technology, then the best place to use it is *right here on earth*. The gravity and atmosphere and temperature ranges are benign, and all the raw materials you need are readily available (especially air and water!). Set up your sealed habitat where you already live. You might never breathe unfiltered air again, but you'll have a positively relaxed and luxurious life compared to people who tried to migrate to an airless, waterless, lifeless, radiation-scorched, poison-covered rock millions of miles away. > > I know this would be hard to do but my protagonist is a software developer who has developed life like AI. So the AI would teach humanity how to fly a rocket or even help with it. > > > The AI has to learn from somewhere; unless you're positing some kind of strongly superhuman mind that can work out the theory and engineering behind a manned space program *ab initio* you'll find that your AI is not necessarily going to do a good job of replacing all those human brains that were killed by the virus. If it were, in fact, a rocketry-focussed AI you might have better luck, but then it won't be able to help you with colonisation. You *could* handwave a "escape the earth and settle mars" specialist AI, but that's a literal deus ex machina too far for me, at least. [Answer] # Maybe, it depends on the AI L. Dutch already pointed out everything there is to say about a lone mans chance for space colonisation. But you mentioned that he has a "life-like AI". I'll assume for the purpose of this answer that it is an *artificial general intelligence (AGI)* and not an *artifical narrow intelligence (ANI)* like we got today. The protagonist does not focus on getting of Earth, he locks himself in a bunker with a supercomputer and works on improving the AI. Specifically he teaches it to improve itself so it can make a better version of itself wich in turn makes an even better one. At some point an intelligence explosion occurs; the [technological singularity](https://en.m.wikipedia.org/wiki/Technological_singularity). The AI has turned into the holy grail of AI research, an *artificial super-intelligence (ASI)*. Assuming the optimistic singularity scenario occurs, meaning the AI is benevolent and cooperative and not nihilistic, hostile and/or suicidal. Now the protagonist has god on his side. The super-intelligent AI could cure the virus, take them to space (possibly mor in line with its desires as Earths day night cycle and the corrosive oxygen atmosphere will be an irritation for it). Maybe it builds a rockets for the protagonist and drops him of at a huge O'Neil colony it build for him or in a Marsbase. Or it merges with him, turning him into an immortal, godlike, posthuman beeing. Or it transports him to a parralell-universe where mankind still exists. Go wild, the technological singularity makes a lot possible [Answer] The general problem will always be supplies. Be it in earth orbit or on Mars, you will need food, water, oxygen, power. In orbit you will also need a supply of mass for keeping in orbit. The ISS for instance is not self sufficient, [based on this answer.](https://space.stackexchange.com/a/2079) it needs resupplies about every 120 days. Now that is for a space station with more than 1 person on it, so maybe you would only need yearly resupply missions, but this already outlines the core issue you will have. Now given the presence of humanlike AI, your story is already reaching towards a sci-fi genre. That means that you could choose to include advanced rocketry technology and an advanced spaceship industry. If these and robotics are advanced enough, its possible that your AI companion could manage these supply runs, although this would require handwaving. At which point you're going to run into the other issues of orbit - namely the effects of living in free fall, and higher radiation exposure. Living in free fall is believed to cause break down in bone density which is really quite bad. Radiation is also bad, the reasons for that being more commonly known. Now again, these are somewhat solvable problems given advanced enough sci-fi. Maybe there is a bigger and better space station in your story, possibly with artificial gravity via rotation to mitigate the issues of muscle and bone decay, possibly with better radiation proofing. However in order for this to be a feasible escape route there would need to be other big advances in technology. The Mars case is harder, and in my opinion requires considerably more technology improvements. [Answer] The AI and the rocket are both relatively easy compared to making a sustainable colony which isn't on earth. Regardless of which rock you stick it on, or even if you just put it in orbit, you are looking at building an enormous green house able to sustain a human population large enough to be genetically viable. It would be HUGE. It would also be significantly easier to build in, say, Antarctica, than to build it in orbit. Antarctica is probably safe from the virus, would give you water to drink, and is considerably warmer than the surface of Mars. You could have the AI knock down the idea of the rocket proposed by humans, using the answers to this post, and propose Antarctica instead. Or maybe a submarine dome? [Answer] # It's a tall order... Based on OP's description of the AI, it has no prior knowledge of space travel, engineering *or* how to sustain life. While I believe that this knowledge could be gained over time, it would require extensive human assistance to interpret and filter the available data. The crux of the issue is **that the AI needs feedback** on whether it did a task well or not. Thus, its ability to acquire new skills is limited by how quickly humans can guide it through the process, and by the teachers' ability to tell fact from fiction. **Training the AI to do anything useful is going to take far too long.** Now, since, in this apocalyptic scenario, humanity's not going to complain, there *is* the option of hijacking existing infrastructure (aircraft, satellites, factories etc.), which would give the AI an opportunity to gather practice data on its own. For simple tasks, like flying a drone from A to B without crashing it, minimal supervision would be required. Assuming your AI's a master of abstraction, and careful preparation and suitable know-how on the humans' part, it might be possible to automate *some* of the tasks to, say, execute a rocket launch with only a skeleton crew. **You'll need some humans** in any case because * Suitable robotic chassis for every step of the process don't exist. * There *will* be gaps in the AI's knowledge you didn't think of. * You don't get any trial runs. *One* ready-to-launch manned space mission just waiting for takeoff is already *incredible* luck. # ...and getting there was the easy part So, congratulations, you got incredibly lucky and managed to launch a handful of people off the planet. Now what? You need to keep them supplied (no matter where they're going), so you have a few months, maximum, to teach the AI how to *run an entire planet*, from farming and mining to building space probes, on its own. Oh, but first have it mass-produce a humanoid, battery-powered, wifi-enabled chassis that can push all the buttons, move the crates and drive the tractors. You did remember to prepare that, right? [Answer] # You can make it believable As a writer you get to make a few assumptions about the environment in which your story happens. Clearly you're not intending to write a futuristic Sci-Fi novel in which humanity has already colonized the galaxy; the question makes it clear that humanity is still earth-bound. But how earth-bound is humankind's technology? To make the basic story work (single person escaping Earth and settling elsewhere), there must be plenty of accessible resources in the Solar System. And here in 2019, those resources are not yet accessible. They exist - there's plenty of evidence of ice on the moon for instance. They're just not at all useful. But what we do have in 2019 is robotic space exploration. It turns out robots are the better pioneers, they survive much harder environments. So what if we assume a few decades of slow development towards space mining? Your much-improved AI explains why robots are still preferred over humans in space, and they have a basic off-Earth infrastructure running for basic chemicals such as water, hydrogen, oxygen, steel, etc. Mars can have a robot base with a nuclear reactor in this scenario. But of course, no habitat for humans yet. **No space agencies** You didn't exactly say what you meant by "no space agencies". But this is another case where you get to choose what it means, as long as you can make the story believable. So you can just say that the organizations ceased to function as the vast majority of personnel became ill or died, and basic society collapsed so the remaining personnel was no longer funded by the state. But as space mining required a fairly steady pace of launches, this process had been automated to a much larger degree to keep costs down. Perhaps SpaceX now has rockets that launch and land from underground silo's, where the rockets are resupplied by robots between missions. And without anyone deciding to launch new missions, all rockets have returned to their home silo's and are waiting for orders. Unbelievable? Well, it's the only way in which mining titanium in space could be made profitable, in your story. ]
[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/139340/edit). Closed 4 years ago. [Improve this question](/posts/139340/edit) Set in the early medieval ages, you know the one, where King Arthur pulled out a sword and got famous. Magic proliferates but not everyone has affinity for it. In this world, those who are magically challenged are usually those with low affinity, the gifted ones can allow magic to manifest as real world objects totally indistinguishable to untrained eyes. However there ain't no such thing as a free lunch in this world so the user must pay for his magic power. It can only be accumulated by basking under direct sunlight at noon. Now with those painful details out of the way I need to know why would anyone waste effort to manifest objects when there is a real genuine version? [Answer] Because the real object is difficult for them to procure for some reason. It could be far away, made from rare materials, difficult to produce or made from expensive materials. For example a sword to put into a stone requires iron ore that has to be smelted, coal, a forge, a cutler and his tools etc. Bathing in the sun at noon is relatively easy compared to travelling even a relatively short distance in that period in order to get the object. [Answer] For the same reason we watch movies. It's cheaper and safer. Because we actually don't want to BE in war theatre. Or we cannot access Buckingham Palace and pet the Corgis. And then we have "influencers". You know the instagram type. Smoke and mirrors (which itself hide a whole explanation on why does this things). The bottom line - the fact that the thing exist don't mean it available for everyone. Why have a model of space Rocket X when there is already existing physical one? [Answer] It takes a master blacksmith $t$ time and effort to make a really good sword. It takes a wizard $2t$ time and effort to make a similar sword. Why would the wizard do it? It takes a master baker $w$ time and effort to make a really great pie. It takes a wizard $2w$ time and effort to make an acceptable pie. Why would the wizard do it? Because right now, I'm up the Khyber pass without a paddle. Nobody has eaten in a couple of days, the bandits are on my tail and I've just found a wizard. The wizard can make both, without having to be a master of either. While it may be harder, slower and less efficient to use wizards for manufacture, what they lose in efficiency they more than make up for in versatility. You don't need a master blacksmith, a master baker, a master carpenter, all you *need* is a couple of decent wizards. [Answer] Previous answers already stated the cost of creation in materials versus the cost of magic. I would add: **Versatility** You're a spy than can't bring his tools/weapons in a specific location? It's not a problem if you can make them appear out of thin air. You're a warrior in the midst of battle, needing a weapon? Materialize it. Your cart wheel broke down and the nearest village is miles away? In short, (depending on how your magic works) it's possibly faster and probably easier to materialize things than to carry them around. You don't have to plan for every possible needs you may have, since you can create the one thing you need on a whim. A lot of contextual applications will occur. **Illusion** You can't tell it's a magical object unless you're trained? Con-artist magician. Sell fakes of valuables, pay for your food with fake gold and lie about your identity with fake documents. (Note that there is probably legitimate purposes to this aspect, besides being a huge fraud). Also, become a licensed expert magician, to detect fake valuables, fake coins and fake documents. **Time** How long does it takes? Maybe a smith takes a lot of time making a sword when you can do it in mere seconds. You won't be a industrial revolution by yourself, but it seems extremely useful. A small point I'd raise is the duration and cost of the item. Just produce enough copy of... let's say sword for an army, and the countryside will soon be littered with discarded ones. Children will be playing with them, villagers will use them as fences, they will smelt them, etc, etc. A strong supply of an item decrease its value. If you make it too durable, then virtually everything loose value, since you can make as much as you want. So either they disappear after a given time, or creating one item is taxing enough you can't do it so fast than a trained artisan could do the same during your recuperation time. [Answer] If given the choice between getting off the couch to get a beer from the fridge or summoning it, I would summon it. If the only cost is skin cancer, I would have my roof made of glass. Probably summoned glass. During the middle ages this is even more so because such magic wouldn't be used just to solve first world problems. Some resources were difficult to procure. Clean, fresh water comes to mind. Good iron ores, or better yet, quality steel would be great for just about everything. Fresh fruits in deserts and at sea would save people from scurvy. People already lived less in the middle ages, so if the only cost attached is a higher risk of melanoma, your mages are actuallly getting a huge profit from life. [Answer] There is one simple reason. Ownership. You new clothes, food, wine, beverages, a castle or two, maybe even a magic sword or so, and you don't have or own them. Solution: Use your magic to manifest them. You have abolished your lack of medieval consumer goods with your magic. Also, if you have manifested valuable material that is indistinguishable their physical equivalents you can sell them and get rich. Manifesting material objects by magic solves ownership and wealth problems. Sorry, gang, once again economic reasons gazump the rest. Another triumph for the dismal science. [Answer] I can go to IKEA to buy a couch. I'm talking about the real world right now. However, if I could materialise a couch without the entire trip to IKEA, arranging a transport home, and then putting the couch together, I'd probably go with that option. I am even somewhat lucky to have an IKEA close-ish to me - it's only about two hours away. In one direction. And they do deliveries, too. I doubt there were as many IKEAs in the middle ages. Suppose I wanted to get one Ye Olde Couche 1. I'd have to go visit the guy who makes stuff from wood who is two villages away. 2. I'd have to make a special order because I doubt he has any Ye Olde Couches at hand. He'd have to make one especially for me 3. That might take, say, two weeks. I'm probably being optimistic here. 4. He might just do a *single* type of couch. He never needed to learn to make another. 5. He might not even offer a variety of woods to choose from. He'd probably have whatever is in the local woods. So, if I want walnut instead of *dark* walnut, because it matches my Ye Olde Drapes better, I probably don't have the option. 6. I still have to transport this to my home across two villages. And that's a *simple* example. What if I want, say, a trebuchet or some armour. There might not even be a decent armoursmith within two days travel from me. Or a...trebuchet-smith. Or whatever the person is called. A conjurer who can produce any sort of good would be extremely sought after. Want a couch? A trebuchet? An armour? The conjurer has got you. Let's assume that making a complete object is very hard or impossible via magic. Perhaps it requires very intricate knowledge of woodcarvery, *and* trebuchet making, *and* armoursmithing on top of any magic study, to be able to produce all of them. Or perhaps complex creations are simply out of the question. However, if that's the case, let's assume that the conjurer can still produce the raw materials. That's still a huge boon. Being able to get high quality materials to build what you need for them is still better than sourcing these from, say, the neighbouring kingdom. And you might be at war with said kingdom. If the conjurer can produce slightly more complex materials like alloys or a gunpowder mix, that you don't normally have access to, it's even better. Whatever the case, the point is that even if you *could* procure whatever the conjurer would magic into existence, that doesn't mean it's *easy*. Or *as easy*. If you have iron but not coal or decent wood to burn, you'd have a hard time forging swords. If you have something to build good fires with but no iron, you still have the same problem. Wars have been fought over *salt* which was a valuable resource back in the middle ages. Being able to provide enough food pushed humanity to build the civilisation we have today. Can you imagine not having a lack of *any* resource? [Answer] Because not everything has the same value-to-mass ratio. Making a handful of dirt by magic is certainly more work than scooping it from the ground. But making a bar of gold might be a little cheaper than mining it. So you might have goldmines that are really just dozens of magicians churning out gold from the noonday sun. Also, as Chronocidal mentioned in their answer, some objects require a large amount of skill to make by hand. Why spend days expertly crafting a watch when you could summon it by magic? A watch has much more value than its component ingredients: the hard part is intricately cutting the tiny gears. With magic, that's much easier. An example from Paolini's *Eragon* is where Nasuada instructs the Varden's magicians to make lace by magic, because the value of lace comes from the difficulty of producing it, not from the raw materials themselves, so you can make a much larger profit margin if you cut production costs and use magic. [Answer] In some cases, crafting complexity: A magically gifted artisan of clockwork may find it easier to sketch out intricate designs, and then manifest the result directly from magic, instead of having to craft tiny gears and jewelled bearings, then carefully assemble the entire construction without getting any specks of dust in it... A material required for constructing your facsimile may be rare, expensive, or hard to work/produce - how much magic would it take for a jeweller to cut facets into a diamond? And, would it 'cost' less for them to simply manifest a pre-cut (and completely flawless) stone? Finally, you may also be able to *deliberately* distinguish your magical copy in some way - taking the magical clockwork example, you may be able to magically manifest a [mainspring](https://en.wikipedia.org/wiki/Mainspring#Constant_force_from_a_spring) that provides a near-constant force for the first 90% of its output, then drops off for the last 10%, in a manner superior to even modern [going barrel](https://en.wikipedia.org/wiki/Barrel_(horology)) [Answer] Ease of use, entertainment, survival, special construction? Lets say your watermain broke. You can create a quick temporary stopgap and then get "real" stuff and call professionals to close it. You get stranded in the cold. You can create something like matches to light a fire or temporary clothing to keep warm. Someone tries to rob you with a knife, conjure a loaded crossbow and rob him right back (or bring him to the authorities, whatever works). You want to impress someone. Some light indoors fireworks could work, or you conjure a flower. Need a quick repair but too lazy to get your tools? Conjure some perfect for the situation and done! Need to pour concrete but removing the support might damage it? You are in luck! Our mages conjure up the supports, and when it's hardened enough they just let the supports fade away! Theres a lot of specialist construction that can benefitnof this kind of production, especially for filling molds that now need specific angles so you can pull it out after hardening. A better question might be when you wont be using it! ]
[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/115341/edit). Closed 5 years ago. The community reviewed whether to reopen this question 12 months ago and left it closed: > > Original close reason(s) were not resolved > > > [Improve this question](/posts/115341/edit) A malefic wizard has announced to the world that tomorrow he will turn all diluted sea salt into sugar. What will the environmental effects be? [Answer] Having so much sugar diluted in water will trigger a massive fermentation: the sugar will turn into alcohol and $CO\_2$ thanks to the action of yeast. The alcohol will kill all the living organism into the water. Even worse, the lack of magnesium salts will make harder for plants and remaining algae to synthesize chlorophyll, with the result that getting rid of all that $CO\_2$ will be harder. Greenhouse effect will boost and temperature will rise. Humans will be too drunk to care about extinction. In some remote places it is possible that [sugarite](https://worldbuilding.stackexchange.com/q/92435/30492) will form, puzzling future archeologists and geologists. The diluted alcohol, over time, will be converted to acetic acid, so the ocean will become a giant vinegar bowl. The acid will attack all $CaCO\_3$ based rocks, freeing more $CO\_2$ in the atmosphere. [Answer] **Wow. That's going to be ugly.** Everything in the ocean dies. Period. Some single-celled organisms might can survive, but not many. Prepare for all those life forms to float to the surface and/or wash ashore and begin decaying. The *fishing industry* just went out of business, along with seafood restaurants, etc. Bacteria and mold thrive at the coastlines, feeding on the sugar as it dries on beaches. This will be ugly, too, since that kind of out-of-control growth will mess up the local ecosystems. All the people producing sugar, from farmers growing beets, cane, or other crops up to the factories that refine those plants into sugar are out of work. Sugar is just too easily obtained now. The current **sugar production industry** is unemployed. **The bacteria will thrive.** They will produce CO2 and alcohol. So your atmosphere will, over time, become a runaway greenhouse gas situation as the bacteria overgrowth reach an equilibrium with the O2, CO2, and sugar levels. Diabetics like me will be doomed. And we can never swim in the ocean again. Ever. We might not even be able to travel to coastal regions, if sugar evaporates like salt does. --- *The rest of this I'm not as sure of...* Does sugar water stay in solution like salt water? Or does the sugar settle out over time? I believe it eventually settles out. I don't think it wants to remain in solution like salt does. But I could be wrong here. If I'm right, though, your ocean floors will eventually be coated in a layer of sugar for the bacteria to consume. Does sugar absorb heat with the same properties as salt? If not, then climate change just got unpredictable. (Combining the CO2 from bacteria with the new heat absorption rules...) The end of entire industries will make life hell. The end of ocean life will make coastal regions a hell of stinking, dead, aquatic life for quite some time. Our food chain will be severely impacted. People will die from starvation -- coastal people, primarily, but people. Does sugar water have the same density as salt water? If not (or if the sugar does settle out), then you've impacted at least some percentage of ocean-going vessels and the amount of cargo they can carry. Does sugar water interact with ship material in any way? Or encourage microbial growth that interacts? The collapse of so many sources of food may cause starvation. But even if it doesn't it'll certainly cause major economic issues, possibly up to and including a new Great Depression. And then the climate changes will doom us all. It's a matter of time before humanity can no longer survive. [Answer] What everybody said about the sweet embrace of diabetic death, followed by the dizzing embrace of alcoholic death, followed by the sour embrace of acidic death. I'd like to add one more thing here. This is a molecule of table salt: [![Salt](https://i.stack.imgur.com/tcgqI.png)](https://i.stack.imgur.com/tcgqI.png) Molecular weight: 54.8 g/mol This is a molecule of sucrose (i.e.: table sugar): [![Sugar](https://i.stack.imgur.com/J1PiP.png)](https://i.stack.imgur.com/J1PiP.png) Molecular weight: 342.3 g/mol Besides the difference in mass, the sugar molecule is much, much larger. If the substitution is a one by one thing - that is, each Na+ and Cl- pair is replaced with one sucrose molecule - then the oceans will expand. We would have some immediate tsunamis as the oceans adjust to their new volume. The planet will also get added mass. [Currently our oceans have a volume of 1.35 billion cubic kilometers](https://en.wikipedia.org/wiki/Ocean), which works out to a total of: $$ 1.35 \times 10^9 \times cubic \space kilometers \frac {10^{12} liters}{cubic \space kilometer} = 1.35 \times 10^{21} liters $$ Each liter of seawater contains, on average, 35 grams of salt. That works out to: $$ (1.35 \times 10^{21}L) \times (3.5 \times 10^{-2} \frac{kg}{L}) = 4.725 \times 10^{19}kg $$ That is almost $ \frac {1}{100,000}$ of the mass of the planet. Now, multiply it by $ \frac {342.3}{54.8} \approx 6.24 $. The total mass of sugar would be $2.9484 \times 10^{20}kg$. The order of magnitude of the solution's mass went up by one. It would be like adding $\frac{1}{10,000}$ of the mass of the Earth to itself. At the very least, the orbit of the Moon and of all the satellites would be perturbed. The lower ones would all deorbit, which would be quite the fireworks show. That extra gravity would probably end up reorganizing the oceans again (after the streak of biblical-proportion tsunamis). Might upset some tectonic plates too. Whatever the biological and chemical conditions did not manage to kill, the mechanical rearrangement of the oceans will. [Answer] Bad things. All the fish would die. Salinity is a key factor in any marine environment; freshwater fish can't live with it, but saltwater fish generally can't live *without* it. Marine life in general would be in for a tough time; some hardier species might survive, but that would be reliant on their food supply also surviving. The sugar itself would represent a huge amount of bioavailable energy, so something - probably some type of microorganism - would start eating it. Eventually this bloom would die off as sugars near the surface were consumed, since there's (presumably) nobody resupplying the ocean with sugars. (It's resupplied with salt by eroding rocks along the shore, but the wizard didn't turn the salt in the rocks into sugar.) I have to assume the smell would be pretty appalling, and the extra microorganisms would probably render seawater fairly hazardous to drink (although you shouldn't drink too much of it anyway) or possibly even to swim in. Depending on exactly how the replacement works (by mass? percentage of water content?) the mass of the oceans might go down, which might be bad news for boats, since they rely on being less dense than seawater to stay afloat. However, I don't know if the effect would be large enough for the reduced buoyancy to be noticeable. People probably couldn't float on the Dead Sea any more. Aside from that, I think the bulk of the ocean itself would be fairly unchanged. (I'm open to correction if anyone has strong feelings on the thermal properties of sugar water.) One thing I'm not totally clear on is how extremely cold water, like at the poles, would react; salt lowers the freezing point, as does sugar, but I'm not sure how the two compare in effectiveness. Human salt production would be affected, but not impossible. A large amount of salt is processed from ocean water, but it's also mined from ground deposits. There would probably be a temporary shortage while new ground deposits were opened up. The sugar itself wouldn't last that long unless it was at depth, where nothing is around to metabolize it. Eventually, salt would make it back into the ocean. This would probably be on geological timescales, though, not necessarily human ones. Oh, and depending on the precise definition of "sea salt", some people who bought overpriced jars of salt from gourmet stores would be very upset with you. ]
[Question] [ One of the syntactical interpretation of the famous linguistics sentence "Time flies like an arrow." is to consider "time flies" as a noun phrase. This makes "time flies" analogous to "fruit flies". For details about this, see <https://en.wikipedia.org/wiki/Time_flies_like_an_arrow;_fruit_flies_like_a_banana>. My question is that if we go along with this interpretation, we have "time flies" which would probably be some sort of flies attracted to time. What would the characteristics of these time flies be? What would their appearance and behaviour be from the human perspective? I am looking for interesting characteristics grounded in physical and/or biological principles. This creature is to be designed for humorous and parodical purposes. As long as it's feasible in a fantasy setting and cannot be disproven given our physical laws, it is an acceptable answer. The limiting rules here are that they are analogous to fruit flies (or some type of flies) as their basic characteristic i.e. attracted to time in some way. As an example of a physical principle, time slows down as you travel faster so they might materialize in a near-speed-of-light spaceship or close to the event horizon of a blackhole. [Answer] A house fly travels through houses, but a fruit fly does not travel through fruit. As someone else has already discussed time-shifting buzzing, let’s consider “time fly” analogous to “fruit fly”. They eat time. Their eggs consume your time. This implies that they are massive. If you stand too close to a black hole, the time dilation will cause the rest of the universe to move quickly relative to you. Similarly, if a time fly approaches you, its gravitational distortion effect will cause you to move slow relative to your surroundings. But while some extraterrestrial species may actually be massive, time flies on Earth are lightweight but capable of bending the gravitational field around other animals using a technique unknown at this time. What benefit does the fly get? All of your potential energy. Consider— a butterfly flapping its wings early enough in history can shift a hurricane. Defer that butterfly and it is like you just swallowed the potential energy needed to move the storm. Fly digestive tract can convert that lost potential into kinetic energy for itself. Time flies only live a single day, but in the billions of years of the universe, they are only into the 6th generation because of dilation. [Answer] The answer you are looking for is in the saying itself: **time flies like an arrow**. These flies like arrows, as little bugs they grow up eating the wood of the arrow body. When they become flies, they consume the metal of the tip as source of energy via metabolic oxidation. They thrive on battlefields, but for obvious reason modern, arrows poor, warfare has endangered the species. Some reports though show that the species is now adapting to consume the wood of the weapon body and then the metal of the weapon itself. Darwinian linguists therefore forecast that the saying will become "time flies like a Kalashnikov" [Answer] Maybe they are called time flies because ancient cultures used them to measure time. Maybe every time fly has a regular schedule it follows every day. * When it is asleep, (or stays in one place) then it is nighttime. * When it is eating fruit and cereals, it is morning. * When it starts buzzing and looking busy, flying from one object to the next, then it is time for work. ...etc. Language has adapted to refer to the time by the patterns of the time fly, e.g. "be in the office when the time fly starts buzzing" or "be at home before the time fly goes to sleep". [Answer] The most mundane possibility, in terms of ordinary biology, is not so much transtemporal diptera, but rather insects with body markings resembling clock faces or even possibility hourglasses. Insects are often known for their colourations, patterns and other markings, so the possibility that insects could exist with patterns or shapes on their bodies similar to horological devices (that's clocks, watches and time-measuring contraptions) is highly improbable. However, it is not impossible. Due to their time-measurement-device-related markings these flies would be named "time flies". While it is conceded that they could also be named "clockface flies", this is too close to being a tongue twister to gain common currency. So they would be more likely known as time flies. [Answer] Time flies are attracted to temporal paradoxes. The name implies a small fly, but in reality they are brutal, quite big and carnivorous. Ever wondered why there are no time-travellers around? Guess who ate them. Whenever some *genius* invents some form of time-travel these little critters find out and *fly* at the invention and the inventor alike, similar to how an arrow finds its target. They then proceed to consume the invention and the inventor. They are the guardians that protect the universe from temporal paradoxes. They are scavengers just like your common fly, always looking for ways to help compost the temporal waste that time-travel invariably leaves around. [Answer] What are the most likely conditions for an organism, no matter how hypothetical, to be called a time fly? Firstly, it must look like a fly. Say, a common fly. Since flies tend to buzz around in an annoying manner, we can assume a time fly will do the same but utilizing a simple form of time travel. This establishes our second criterion. This is basically a time-shifting dipteran. This basic form of time travel can operate with the fly shifting into either the future or the past. Presumably with some compensation for spatial displacement due to the motion of a planet like Earth's orbit around the Sun, and around the galactic centre. Such a time fly will be even more adept at avoiding being swatted since it can shift to a point in time when the fly swatter isn't about to hit it. Accordingly a time fly will resemble a normal fly and it will be even more annoying than ordinary flies because its ability to switch forwards and backwards in time. [Answer] Time flies consume time, but contrary to what others have said are tiny. Effectively invisible to the naked eye they accumulate around computers, cinemas, and especially large concentrations of alcohol. You will occasionally encounter them in other areas, but they're most noticeable by the symptoms of their presence. You'll know they're around when someone says something like "how did it get so late", "doesn't time fly", or "where has the time gone". They particularly like bars, one moment you step through the door and the next thing you know it's closing time and you're being thrown out. the reason for this is the high concentrations of time flies found around alcohol. And yes they fly like an arrow, speed is a function of time and since they've consumed the intervening time, they're fast. They should be detectable by a good wizard, or a scientist with a selection of strategically placed clocks, containment and direct observation are left as an exercise for the reader. [Answer] Time flies like arrows because they are fast moving elongated objects that move axially. Slow moving stuff is incredibly big in the time-dimension, fast moving stuff is small in that aspect. (Think about measuring one of the three space-dimensions of a house, by walking by it, and calling out whether the house is beside you. One step: Still there. Two steps: Still there...... Thirty steps: now ist gone! Same for time: Go forward in time (meaning stand still and exist), and call out whether the object beside you is there: second 1: There. second 2: There. ... second 123134: Still there. It's a house. Gonna take awhile. Now sit there while an arrow flies by (and remember: Time flies are tiny, so they don't see so good. Stuff needs to be near them to appreciate it. No knobbly stuff either, moving knobbly stuff to a time creature is like a rapidly expanding and contracting monster. Scary. Nice, smooth arrows: Great. You sit near them, the view alters, soothing like staring at a tumble-dryer (which they like second best). Modern aluminium-shafts with paint on it? bliss. Practically like TV. [Answer] Time flies could be wasps. They would have uniquely shaped nests, with a dark flat plate at the top to collect heat from the sun, and a narrow centre in the middle that can be easily blocked to protect the bottom of the nest. This would make the nests resemble hourglasses, leading to an association with time. These flies might live near human cities. They might learn that during war, many people die. Arrows might be more obvious than corpses, depending on what fletching is used. This would lead to the time flies liking arrows, as they would learn that arrows are normally in some sort of food [Answer] **Good news, I have one!** This was passed down to me by my uncle. He was a great explorer and keen amateur entomologist. I have sworn an oath not to reveal the whereabouts of this species as they would no doubt be hunted to extinction. However for someone so keen as yourself, I think it only fair to show you a photo. [![![enter image description here](https://i.stack.imgur.com/Zrs7n.png)](https://i.stack.imgur.com/Zrs7n.png) You may have noticed that they are not flies, but beetles. However 'fly' is their local name. They actually make chirping noises on the hour except at night when they flash like fireflies to indicate the time. > > Credit to <http://insectlabstudio.com/> for the bug picture > > > **NOTE** They do not in fact like arrows, this is a popular misconception. Their name comes from the fact that their main diet is Arrowroot. [![enter image description here](https://i.stack.imgur.com/3atGY.jpg)](https://i.stack.imgur.com/3atGY.jpg) ]
[Question] [ **This question already has answers here**: [Lifeform - resistant to gunfire but vulnerable to melee](/questions/13024/lifeform-resistant-to-gunfire-but-vulnerable-to-melee) (25 answers) Closed 5 years ago. In my story, I want a creature to be immune to bullets, but giving it bulletproof skin seems too obvious. I want it so that you could shoot the creature a few times at its seemingly vital spots (the head, heart, etc.), but it won't die right away and can still escape or attack you. The best way to make sure it dies quickly is by draining most of its blood, which means you have to get close enough to cause a large wound with a bladed weapon. Yes, I know you can just use a really big gun or explosives to achieve the same effect, but in this scenario, the options are limited to something relatively cheap, lightweight, and doesn't cause a lot of collateral damage. To give you some image, the creature is about as agile, as strong, and as big as a polar bear. Preferably the reason it's immune to bullets is based on real animals, or at least something that could exist in the natural world. [Answer] What about a dense skeleton? The skull would protect the brain of course, and you could have a ribcage where the ribs are more tightly packed (or even overlapping dual layer, allowing expansion in both layers but still protecting against vital shots) so that lungs, heart et al are protected. You still need a circulatory system so the idea of large trauma from a blade still works. Sure, you could get a shot into the arms or legs, but that would not be fatal. Even a stomach wound wouldn't kill the animal immediately meaning that it could still attack you. It violates the possibility of the brain, heart or lungs being shot, but still provides for firearms to do damage generally, just not in critical areas that would cause immediate death. This does have some precedent in nature; certain herd animals have hardened skulls, and there are plenty of dinosaurs with hardened skeletons as they used parts of their bodies as clubs, rams or spears. [Answer] Um why not use an actual polar bear? Or something very similar; bears, especially the big bears, (Polar and Grisly) are notoriously hard to kill with small calibre rounds, the combination of muscle layers, fat, and fur over their primary body cavity makes getting at their organs really unlikely with handgun rounds. They also have very thick muscles and bones in their skulls so headshots often lodge near the surface breaking bone but not punching through. [Answer] Amorphism, if the creature has no vital organs but rather is composed of "full function" non-specialised cells that all do a bit of everything but require a certain critical mass to function as a whole. Then point damage like a bullet wound does little to no damage to the overall organism while cutting it up with a sword reduces individual sections below survival mass killing chunks of it off until the whole no longer has enough cells to grow back. Something like the [Oozes](https://www.d20pfsrd.com/bestiary/monster-listings/oozes) of Dungeons and Dragons or Calvin in [Life](https://en.wikipedia.org/wiki/Life_(2017_film)). Real world examples of amorphic life are the [Sponges](https://en.wikipedia.org/wiki/Sponge) that have mutable cell functions based on location rather than a fixed function for a given cell. [Answer] ## Backup Organs You can make it resistant to most attacks, including bullets, by having redundant vital organs. Combined with a fully shared cardiovascular system and enhanced coagulation, this seems to fit your prerequisites. * Shooting it will hurt and damage it, but the backup organ will take over, allowing it to flee and fight another day. * Enhanced coagulation makes sure normal wounds not targeted to drain the blood supply will not result in too much blood loss. * A fully shared cardiovascular system allows major blood drains to be fatal. Examples of this exist in nature where certain animals have multiple copies of the same organ. Taking one out vastly reduces their quality of life, but still allows them to survive (Octopi and their three hearts, most insects and their compound eyes etc.). Evolution is as such not a problem, your species would just take existing features and take them to the next level. [Answer] * **Resist piercing:** Projectile immunity is usually best achieved by avoiding getting pierced. Some ways to shed bullets include: + hard surfaces + angled surfaces + low coefficients of friction + active deflection (springy bristle like hairs could provide this, as would orienting body surfaces) * **Resist momentum:** Projectiles impart momentum and that is the source of damage. Ways to resist imparted momentum are: + having a much larger mass + "low viscosity" or low yield strength (if we fail at a point then we can't spread the momentum to areas adjacent to the point as easily) + mass shedding. Having a skin layer absorb momentum and shear off means we have ablative armor that carries momentum away . * **Die to bleeding:** + Blades would have trouble finding purchase on a surface smooth enough to help deflect bullets. But conversely that may make catching on the non-slick wound easier. Repetitive damage in a single area is generally not good. + In a creature with low viscosity overall it would lose internal fluids quickly. To not die from a bullet it would need something like a self-healing skin, porous and highly elastic. So bullets could open a pinhole. But a blade would open a larger wound which would be fatal. Alternatively you could add something like platelets that congeal on contact with air. Larger wounds are just harder to congeal. + Extremely hard materials could be brittle (typically a standard trade-off) so the higher impact from a blade or hammer could be enough to break it where a bullet would not. Death by bleeding then just being standard. + Extremely large objects absorb the momentum outright and the bullets and blades can only go so deep. But Blades have the potential to hack away chunks of material and dig deeper. Something a bullet has a hard time doing. Hardness and mass tend to hand-in-hand material wise. So you could go with a tank-like creature. Alternatively something akin to a slime with special skin would work as well. Mix and match if you need protected areas (skull for example). Other options exist as well. [Answer] Your creatures may have a reasonably thick layer of [ballistic gel](https://en.wikipedia.org/wiki/Ballistic_gelatin) or blubber-like material under their skin, which scope shall be to slow down and thus absorb most of the kinetic energy of bullets, sparing damages to vital organs. You can either change the density of the material (shortcoming: it makes the thing heavier) or its viscosity to improve the effectiveness of the dissipation. [Answer] How big is this creature allowed to be? I'd like to take this in a different direction than the other answers: **make the creature "sparse"** (as the crown of a tree) and/or large (as a coral reef), so that point-effect weapons (such as bullets) have a very low chance of doing significant damage. Maybe combined with vital organs somehow being distributed or in unforeseeable places, and you really have to hack it to pieces in order to kill it. I realize this makes it look more like a *very lively plant* than an animal, but depending on your reality ... that line can be surprisingly blurry anyway. [Answer] Redundancy. Bigger than necessity organs due to evolutionary pressure to survive wounds and duplicated vascularisation with the possibility of closing many veins/arteries if severed. Wherever you hit, there will be another part of the organ able to take over the function and the blood drain will be minor because the tissue can survive a long time without blood while healing and the arteries are closed or almost closed. People can live with [literally half their brain missing](http://www.bbc.com/future/story/20141216-can-you-live-with-half-a-brain), make that per design and you can destroy half the head without problems. Bonus: to kill it you need to severe both vital arteries at one of the few points where they are near each other. [Answer] **FUR** What about a massive stubborn fur, that is thick enough to absorb most of a bullets energy or/and deflect it from it's original path. **HORNS** The creature also could have horn like growths around its vital spots, which can deflect a bullet from the vital area when incoming on certain angels. This still mean that a bullet may be deflected to a less vital area or if shot at the right angel (which might be difficult) still might hit a vital area. This makes it also very challenging to hunt such a creature. [Answer] **Self-Regenerative tissue** your creature has a very fast inmune and regenerative system, making beheading (or very big caliber shots on the head), and thus cutting all neural links, the only way to kill it. **disclaimer: your creature might have strong bonds to young-adult self destructive women, cigars, muscle cars and alcohol.** [regeneration by chemical reaction is possible](https://www.sciencedaily.com/releases/2016/04/160428152117.htm) [![enter image description here](https://i.stack.imgur.com/931LF.jpg)](https://i.stack.imgur.com/931LF.jpg) ]
[Question] [ In a magic, high medieval, setting what factors could contribute to governments avoiding maritime affairs with the exception of perhaps simple coast guards to prevent smuggling, **given they are coastal nations**. Which is to say that long haul transport of people and cargo is done primarily by private individuals, and not even at the behest of government organizations. **For additional context** This is to help prevent nations separated by sea from interacting in official capacities. As well as reducing the availability of cross-ocean/sea travel for plot purposes. [Answer] ## Peace! If a region is generally peaceful at the macro scale, then there's less *need* to ramp up military might. Notice that North America didn't really develop nations OR naval armadas prior to the forming of USA. They had fishing and trade, though. They also didn't develop large armies, either, so there's that... ## Materials or Skills? If your nation doesn't have access to the raw materials necessary to build a navy, they may not have a maritime affairs focus. If you can't build ships, then you don't need a navy. This could be because you lack the lumber, or because you lack the know-how to build a competitive naval force. ## Low population density If your population density is low, you're less likely to need to expand. It takes land to support a growing population, and sometimes it's easier to take someone else's land than to continue clearing and maintaining your own. ## Religious/superstitious pressure A local religion may have strictures against oceanic travel, or against the concept of "big government" that would meddle in naval affairs. Or there could be some sort of perceived rule against the sea, so only a few people are brave/foolish enough to attempt oceanic interactions beyond near-shore fishing. If that taboo extends throughout the nobility, then they wouldn't even consider forming a naval affairs group. ## Treaty There are various reasons your nation might have a treaty-based ban on naval affairs. Maybe they lost a major naval war and the treaty was all that preventing them being wiped out. Or maybe they and another powerful nation signed some mutual protection pact that said they would have no naval powers as their part of that agreement (Cold War type bans on naval warfare, or maybe your nation supplies ground troops and theirs supplies naval forces...) ## Technology/Magic Maybe your nation is so advanced, relative to their neighbors, that they don't need naval affairs. Or so far behind their neighbors that having a naval affairs division would be utterly pointless. Maybe, via technology or magic, they skipped ocean travel entirely and went "straight" to planes or dirigibles. After all, a floating/flying aerial vehicle is more useful than one trapped on the water. ## Infighting Perhaps your nobility is too busy stabbing each other in the back (literally and/or figuratively) to form a cohesive naval power. Maybe they're too clanish to focus their energy together towards building a navy. ## Monsters Here there be dragons. Or Kraken. Or some other beast that has a taste for anything large enough to represent ships of the line. ## Wealth Building a naval affairs requires money. Maybe your nation simply cannot afford to do so. ## Geography/weather If the oceans are too shallow or there aren't enough natural harbors, you may never develop the larger ships like we see during the height of the Age of Sail. Likewise, if wind patterns are wrong, your nation may not be positioned to launch a strong naval vessel — winds too week, or to strong but blowing inland off the sea for example. Or maybe the nation is too far north or too equatorial — people just don't have the temperature range they need to handle ocean voyages on a major scale. ## Type of government If they are a corporatocracy or ruled by guilds, the guild factions may prefer to keep the naval powers to themselves and away from rival corporations/guilds. [Answer] Water acts as a magic energy "ground". Magical energy flows over the surface of the world and "pools up" in living beings. Water (for some reason) acts as a ground. It dissipates pools of magical energy, radically lowering the ability of magic users to function. This is the reason for ancient myths about evil spirits not being able to cross streams of running water, etc. A small stream will cause a "hiccup" with spellcasting, but nothing major. A large body of water like a lake or an ocean can completely drain the "pool" of magic energy, leaving everyone reliant only on mundane skills, technology, and tools alone. This SHOULD not be a huge problem, except that unlike our real world, people are USED to being able to fall back on a little bit of magic when things get really hairy. Middle Ages technology makes oceanic travel risky at any time, with a need for highly skilled mariners and very high tech (for the time) and expensive ships which might be lost at any time in a storm. Without being able to bring along a couple magic users "just in case", large organizations tend not to put a lot of importance on (or risk the royal treasury making fleets for) ocean going adventures. This is the realm of small groups willing to take on the larger risk of operating in an effectively "magic null" environment. [Answer] Hinted by AlexP: a commercial shipping guild (modelled after the Dutch United East Indies Company) which out-evolved the growing state. Kings may have established their power by establishing feudal control over the local nobility, but this takes time and effort. In the mean time, the shipping guild simply became wealthy through trade, founded their own navy for pirate protection, and became the *de facto* national navy. The King would recognise their independence, while the shipping guild in exchange would support the King's reign on dry land. Now, the King *could* of course buy transport on board these ships, but he's not entirely happy about that shipping guild showing off their independence. Having to pay for transport is beneath him, *not* paying is an issue for the shipping guild. But as long as the King doesn't *want* to use the ships, the question of payment can safely be skipped. If this happens in a few countries, their shipping guilds may become wealthy by exclusively trading with each other. Such an alliance might also explain why no King dares to ban the national shipping guild. He might find himself embargoed by the other shipping guilds, who might want to make clear to *their* Kings how bad an idea it is to interfere with international trade. And since the shipping guilds are in contact, and the Kings aren't, the guilds have the upper hand in joint operations. Magic isn't really needed, although it can be used to add flavor. Magic is going to be a source of wealth, but are the required exotic ingredients provided by the shipping guilds? [Answer] Answer in list form below, problems with scenario up front. **During the time period you speak of, historically, there wasn't much in the way of government involvement in maritime affairs, particularly trade.** Until the advent of guns, Naval Warfare consisted of shipping troops mainly with occasional battles and protecting coastal settlements from raids. Most countries only cared about keeping their villages from being raided, that's what they used the ships for. They did police their harbors, and tax things coming in, as one would. **Even in more modern periods waters are considered NOBODY's territory.** They are called international waters for a reason, and that's because no government seeks to police the oceans closely. You're asking why a government might not have interest in maritime affairs while still saying they have a coast guard and trade, which I would count as interest. **If they have a coast guard, sorry, they are now officially MORE interested in maritime affairs than most coastal Medieval Governments** The coast guard, as an entity, for example, did not exist in England until about 1800. Prior to that the NAVY fulfilled the functions you might think the coast guard would. Patrolling the waters, making sure things were not being smuggled, keeping people from attacking coastal villages. Post Medieval, well...that's when things get fun. East India Company, the city states of Renaissance Italy. But still, the actual governments were primarily interested in a) WAR and b) taxing stuff on their land/egress to them, and eventually c) exploration to get more land and stuff! If the nations trade and have a pirate problem (that is, goods are either not getting to other countries or they aren't getting to collect taxes on theirs) they may declare a bounty on pirates through the government. **As long as governments get plenty of money from the resulting trade, they won't care who runs the sea.** But that doesn't mean that the trade organizations won't want to try to get in on the ground floor of the government and skew things towards themselves. Here's how that might not happen. * two or three equally powerful trade orgs, all they can do is ensure the others don't get influence. * the government developed a "hands off" policy where anything goes on the high seas because it's best for the country, and any internal struggles can get solved on the seas (this actually, could create a whole culture OR not, as you please. * governments don't care to explore because it's too dangerous. * government backing of a sea voyage or trade resulted in economic collapse in the past. so it's now verboten. what this means is that there are not any of the old-timey equivalent of government grants for anything on the high seas--so no ruler can give over $$ for any research, exploration, or trade. I see mundane reasons like not having the wood resources, and in-fighting such have been covered. Here's how a Navy might not get formed, using weird magic stuff. There can't be pirates or raiders. Or any attack from the sea on them by another country. (By that I mean that they won't ship soldiers over to attack the land). * a worldwide religious convention makes it a bad idea to do any sort of warfare from the water. + Because if any blood is shed it awakes the actual kraken. + or an impassible whirlpool, which is just bad for trade. + or a storm. or lightening or whatever! * metal cannot be transported by sea. So forget arms and armor! does not mean a more enterprising country might not use wood and arrows... [Answer] There is one nation in history that had a massive coast line, and apart from a short stint in the 1400s it almost completely ignored the sea trade until the 1800s. That would be China. There are several reasons why they didn't go to sea. The first is the rivers: river transport was safer (easier to eliminate pirates on a river). They also dug canals which meant that you could go anywhere on the rivers. Rivers were also easier to tax, you just stick a tax post on a choke point in the river. The second is policy. For centuries the government was focused on landward expansion and agriculture. The amount of land they had available meant that there was no real push to expand overseas. This combined with the prevailing doctrine that China was the Middle Kingdom and everyone would come to them and pay them tribute meant the land was China's main concern. The third and possibly most applicable to the question is wood. Up until until you start seeing coal burning stoves wood was in massive demand for heating and cooking. If you add to that the need for charcoal for industrial forests (which caused the deforestation of several areas) and at least wood framing for buildings wood is in massive demand. Only the very wealthy are going to be able to pay for the wood to build boats. If the government is interested then you're likely to see only a few wealthy traders making high risk, high reward journeys. [Answer] ## Deep sea travel is controlled by a single Navigator's Guild Yes, adapted from Dune. To safely travel beyond coastal waters, magic is needed. Without a specialized mage to navigate the storms/mists/kraken-infested deep, ships are not going to arrive at their destinations. These mages have united in a multi-national guild that is beyond the control of any one king. They adopt a fairly neutral attitude but are not going to risk their members in maritime battles, so the kingdoms have no way to fight across the seas. This reduces the need and ability for official interactions, leaving the seas open to private trade. For an additional twist, it could be that there is actually no danger in the seas other than that created by the first Navigators, but a century or two later, everyone just assumes it's impossible without them. [Answer] **Rampant piracy that benefits the nation** Your coastal/island nation is host to innumerable pirates. These pirates prey primarily on trading vessels of another nearby nation. This other nation is strict about their trade with your nation, perhaps extremely high tariffs or trade limits. The pirates allows these products to enter your country without worrying about relations or tariffs. In return for the government's blind eye, the pirates mostly avoid trade vessels belonging to your nation and keep your neighboring "ally" in check. For a loose historical example, see the [Wakō](https://en.wikipedia.org/wiki/Wokou), raiders based out of Japan who raided the coast of China and Korea. [Answer] The simple solution is that there is nothing (more) to gain from the seas. The governments are usually concerned about simple things like maintaining security in the society. This includes keeping internal unrest to the minimum and also making sure no outside factions pose a threat to the society. There should be enough resources available to make this possible. If there are such resources in plenty then there is no actual need for the government to be interested in outside matters. It may be that the ruling class or the society demands things that aren't available locally. This creates a need to push beyond borders and shores. And then the government is naturally interested in keeping its citizens safe and must expand its sphere of influence. This does not necessarily mean sending troops out. If friendly factions can guarantee safety, then there is no reason to commit manpower. If all the necessary resources are available by land, there is no reason to put too much resources in seafaring. Occasional raids by foreign ships can be repelled by land-based fortifications to some extent. And since China has been mentioned already, I might point out that its coastline curves outside for the most part, making inland routes shorter than sea routes. Such geographical features influence the need for ships, as well as terrain types and dangerous sea routes etc. If separate nations are all doing fine on their own and have no need to be envious of others, then they need not be dealing with each other too often. This could change rapidly, however. As history has shown, internal turmoil can lead to expansionism. But that's a discussion for another topic. ]
[Question] [ So.. I've decided to kill all the humans on Earth. Just a routine fumigation prior to a terraforming job. Although I don't mind a bit of collateral damage I do want to keep most of the plant life and the ecosystem that's necessary to support that. I plan to get this done over 200 to 1000 years. My preferred method is slow-acting poison. Slow enough that nobody knows I'm doing this. I'm not going to fly space ships in and start shooting everything up like in the movies because I'm at a huge metabolic disadvantage and humans would, once they figured out I was malevolent, run rings around me and my kind. What kind of poison's good for a job like that? It's eventually going to draw attention, no matter how it works, so it's probably best if it doesn't cause too much obvious drama while there's still any hope for treatment. [Answer] You have various options to get rid of the civilized part of humanity. **Chemical poison** The roman empire was poisoned over centuries from using lead to build their water pipes and cups. They also used to boil wine into lead pots, since it gave their wine a sweet taste. > > Lead was used extensively in Roman aqueducts from about 500 BCE to 300 CE Julius Caesar's engineer, Vitruvius, reported, "water is much more wholesome from earthenware pipes than from lead pipes. For it seems to be made injurious by lead, because white lead is produced by it, and this is said to be harmful to the human body." Gout, prevalent in affluent Rome, is thought to be the result of lead, or leaded eating and drinking vessels. Sugar of lead (lead(II) acetate) was used to sweeten wine, and the gout that resulted from this was known as "saturnine" gout. It is even hypothesized that lead poisoning may have contributed to the decline of the Roman Empire, a hypothesis thoroughly disputed. > > > Also Arsenicum is a slow acting poison, and there are reports of the first copper mining population being poisoned by the Arsenicum rich wastes of their mining activity. **"Pleasure" poison** Start a company which sell junk food, make it cheap and make it cool by using a lot of advertising and branding. Make it an habit and socially accepted. In parallel demote healthy activities and induce mankind to be more sedentary. Use your lobbist to reduce health services. Hearth diseases and obesity will make the job for you, while you earn nice moneys out of it. For the few thousands living far from civilization, deeply hidden in forests all around the world, you have to decide. You can keep them as "no nuisance" since you got rid of 99.999999% of them and they always refused civilization. Or you can send hunters to target them. [Answer] Feed the people memes that encourage them to have below-replacement fertility rates. Preferably get the militarily strongest groups to believe the memes enough that they "convince" all groups to accept the memes. A total fertility rate of about 1.6 children per woman results in a population decline of about one percent per year. After 1,000 years, that is enough to reduce the population from 7,000,000,000 to 300,000. A total fertility rate of about 1.4 children per woman results in a population decline of about 1.5 percent per year. After 1,000 years, that is enough to reduce the population from 7,000,000,000 to 2,000. If the memes are based on ideas like "overcrowding" or "living space is too expensive", they might need to be replaced when the population gets low enough that there is obviously lots of room. For example, a population of 20,000,000 is less than one person per square mile, even if nobody lives in deserts or mountains or glaciers. With population decline rates of 1 - 1.5 percent per year, that population would be reached after about 400 - 600 years. [Answer] L.Dutch has made an important point about the people living in far flung, *uncivilized* corners of the world. Unless you use a global airborne poison, these folks will not be affected. But a global airborne poison would be immediately detected and your agents will be exposed. So, we have either of two options: * use a genetically engineered pathogen which only targets humans * use chemical poisons to first poison the *mainline* population of humans and then target those in far flung communities **Genetically Engineered Pathogen** First you collect all the viruses and bacteria which only target humans (smallpox, typhoid, whooping cough etc). Now you enhance their capabilities and make them more deadly. For example, you could create a flu virus which makes infected cells produce and secrete ricin or abrin or shigatoxin into the bloodstream. This would make flu a killer. For the worst hit, you could work on the HIV virus and enhance its functioning so that it doesn't have to be injected into the bloodstream to function and would start destroying the immune system when inhaled. The possibilities are endless. Once you create your super pathogen, you release it in the atmosphere through aerosols. This would target all the human population and would make it extinct within a few generations. **Chemical Poisoning** Here again, you have endless possibilities. You could go the painful route, by spreading carcinogens into the environment and create a gigantic spike in cancer rates. This would quickly overwhelm all national health budgets and situation would soon be out of control. You would easily kill 80% of the population within a few decades or so. Or if you want to go the classical poisoner's way, you could use a slow poison such as copper sulfate, sodium selenate, corrosive sublimate etc, grind them very finely and spread them in the atmosphere through aerosols. The downside of this method is that these mineral toxins affect all complex life alike, so all large animals in the ecosystem would be getting affected alike. You would have a lot of dead animals to dispose off, at the end of the day. [Answer] A virus that damages the ovaries of baby girls so they don't produce eggs. By the time the girls hit menarche and anyone notices the problem, the virus is long gone, damage done. You have essentially sterilized the population without giving CDC and WHO any clues about the source. Make it something that easily lingers in the populace, like a light version of common cold. *(I heard about this plot somewhere but I do not know where, so I cannot cite sources. If anyone knows origin of this idea, please edit this answer to add attribution.)* [Answer] The general theme I see with slow poisons like this is that: a) people don't realize they're consuming it; b) it is commonly used in various products, especially in products that hold food or drink Do we have something like this currently in our society? **Yes, plastic** More specifically, plastics made with [BPA](https://en.wikipedia.org/wiki/Bisphenol_A). They generally aren't biodegradable and instead breakdown in conditions of high heat or UV light exposure and even then it's just smaller pieces of the same plastic still polluting the environment. It isn't toxic in small amounts (and I'm not even sure how toxic/deadly it is in large amounts), but if you can create an environment that has a overwhelming build up of the component, to the point that it's impossible to avoid consuming it in significant amounts, this might work within your timeline of 200-1000 years. You can even say your aliens are already doing this due to how commonly used they are and how often waste plastic is dumped in landfills and oceans. Yes, humans are very slowly moving away from using plastics as an easily disposable resource, but for your aliens, if they can slow or stop that process and keep humans using BPA-based plastics until pollution reaches a critical amount, this might create a toxic enough environment to kill off most complex life on earth. However this might leave a problem of cleanup for your aliens. Or use something similar that your aliens are immune to and is more deadly to humans. Another route could be a biological attack, but that would probably occur on a much shorter timeline. [Answer] Introduce [right handed microbes](http://www.nature.com/news/mirror-image-enzyme-copies-looking-glass-dna-1.19918) in the Earth's environment that will produce the mirror version of a chemical compound that is critical for some biological function and such that this mirror form will be lethal. The microbes will be released in some remote location where it will slowly multiply, releasing small quantities of the chemical that will not be noticed before it is too late. The microbe has very slow metabolism compared to most microbes we are used to. It will divide only once every 5 years and you start with just 1000 microbes. It will then take 100 years for this to grow to a billion microbes, which only produce a tiny amount of the toxin and that at the remote location, so that won't be noticed. But after 400 years the microbe will have colonized the entire planet and vast quantities are produced. When people start to die, chemical analysis will not yield immediate answers, as the chemical compound looks very much like its normal mirror version. Its spectrum is the same, MRI scans won't show a difference, and it won't show up as a different chemical quantity in a mass spectrometer. The microbe itself won't be easily detected either, because it doesn't grow on a petri dish. DNA analysis won't work either as its DNA has the wrong handedness. [Answer] The problem with poison is that it can't be inherited so you would need to kill 3 generations in the span of 60 years to succeed. Otherwise they will notice. Assuming that one generation is 20 years you want to kill 10 generations. Which I assume you want to do to not get attention from mass dying. So you go for he low hanging fruit which is autoimmune diseases. Lupus. You can't treat him and when he have vide range of organs it can attack. Then when the developed countries are occupied with this you send good ol' black death, flu, HIV and ebola. You could go with rabies but that would also take a toll among animals. And after let say 200 years you go after remote communities with smallpox, malaria. [Answer] On purely technological means, you can't. First you have to degrade them, distribute pseudoscientific beliefs between them, undermine their education and promote a low-educated culture. After that, you can help them to accept some longterm poisonous thing as ordinary one. Best if you decrease the fertility rate of the females. [Answer] Develop a new [retrovirus](https://en.wikipedia.org/wiki/Retrovirus) that makes the humans barren. > > Like in the book *Inferno* from Dawn Brown > From this humans can reproduce in slower grades and slowly dies out. > > > Or Plan 2: Develop Viral vectors to induce Huntington’s disease. [Answer] Encourage burning fossil fuels. If you can access the communications networks, add conspiracy theories and junk science denying climate change. The resultant natural disasters will kill off the majority of humans, and the breakdown in law and order will kill off most of the rest. You will have to search for and kill the survivors manually, but by then they won't have the infrastructure to be much of a threat. The best part: not only is it undetectable (since you're not actually doing anything), but nature will reabsorb the $CO\_2$ into biomass, given a few hundred years. [Answer] Induce an increasingly fast-acting prion disease. Per Johns Hopkins, prion disorders currently hit around age forty to sixty. Ideally, you'll be able to cause it to mutate to take a decade or two off this each generation of infected. This will probably work best if you reveal yourselves to a select few elites who can manage society and sway public opinion during the last generations. Eventually there wouldn't be enough healthy people to take care of the increasing numbers of frail and senile. Your elites can step forward to "save the children"...whether for food, slavery, or mass execution. Along with humans, you'll probably kill any mammal (maybe more, I'm not a scientist) that eats human remains but that might be acceptable as collateral damage to you. <http://www.hopkinsmedicine.org/healthlibrary/conditions/nervous_system_disorders/prion_diseases_134,56/> [Answer] **You need multiple attack vectors.** If you use a single attack vector, humans will stand a chance of discovering that vector and finding a way to counter it before they are wiped out. Humans are annoyingly persistent that way. As others in this thread have mentioned, reduce birth rates. This can be done via several simultaneous attacks that hit in reoccurring waves. 1. Genetically modify various existing bacteria/viruses (common cold, flu, etc.) to attack the ovaries and testes. You won't have 100% infection rates with this. But if you infect 50% of the population and 50% of the infected are sterilized, you've reduced the global pool of child-bearing humans by 25%. And these viruses self-mutate and linger, so each successive generation will face re-infection over time. 2. Genetically modify various existing bacteria/viruses (not the same specific strains in #1) to increase social anxiety disorders and other mental issues that reduce one's ability to interact socially. This will make people more prone to isolation from each other on an intimate level, again reducing humanity's birth rates. 3. Targeted bacteria/viruses that attack various food sources. If you can find viruses that wipe out 50+% of existing corn, wheat, and rice varietals, you will devastate population. That devastation will likely lead to warfare and national isolationism, as people fight over the remaining food. That will further depopulate your planet. Yes, you might wipe out those crops entirely from the planet, but most of the non-human life will survive the loss. 4. Pollute the oil wells. Engineer a bacteria that breaks down crude oil and can survive in the hostile environments of deep oil wells. Spiking one of their primary fuel sources will devastate economies, destabilize national relations, and lead to war. The death tolls will be catastrophic for those annoying humans. 5. Pollute the coal mines. Same as #4, but for coal instead of oil. 6. Improve existing bacteria and viruses' ability to resist human medicines. If their antibiotics fail, then they get sicker and die faster. And if this is the 2nd or 3rd wave of bio-attack, their medical research teams will be overwhelmed and incapable of facing the new attack with efficiency. Keep up the good work! 7. Annoyances. These are minor, trivial things that will prove annoying to repair. The expense to do so will eventually outweigh the nations' resources. Destablize the orbit of communications and GPS satellites, cause electrical surges in various power grids, introduce microfractures into bridges and dams so they fail more often, introduce contaminants to major food storage depots, accelerate the oxidation of metals in trains or planes, etc. This is sort of a death by a thousand cuts. By themselves, none of these acts will kill enough people to matter. But keeping a background level of these events will rob resources from the other 6 items in the list. It will strain their ability to respond quickly or with enough person-power to mount effective responses. 8. If you have the technical resources to do so, trigger tsunamis and earthquakes on an slowly-increasing frequency and severity scale. These have devastating impacts on human morale as they simply cannot defeat nature, and their religions make it difficult to understand why nature would be against them. 9. Introduce lead and other slow-acting toxins to city water supplies. Sure, they test for such things, but it takes resources to clean up the mess. And if they keep getting poisoned, the experts capable of cleaning the mess will get fired, replaced by less experienced, less capable people. Again, humanity is annoyingly clever, so they could probably overcome any one item off the list. Maybe even any 2 or 3. But not the entire list. Each will impact a different segment of the population and further weaken the rest until the entire thing collapses. [Answer] Use a multi-step approach. First render the humans vulnerable in a way that they won't obviously notice, then expose them to a threat which is fatal to the modified humans. The most promising long-term strategy is, I think, not a poison *per se*, but creating genetic or epigenetic changes in human DNA that would unexpectedly turn out to be harmful. The timescale you mention (200-1000 years) is way too short to genetically-engineer humans to have specific gene in the natural way. The mechanisms of evolution - gene drift, gene flow, natural selection - with as large and diverse populations as humans work on the timescales of ten and hundred thousand years. Therefore the best strategy is to lure the humans into doing artificial genetic modification on themselves. Suppose that you can design a gene with particularly deadly hidden vulnerability, which at the same time brings extreme benefits to its carriers, for example, supernatural attractiveness, longevity or amazing resistance to common diseases. Which parent would not want to have this for his children? Indeed, in the future society doing this particular gene therapy or even (inheritable) germ-line modifications would be seen a moral imperative similar to vaccinating your kids nowadays. As for the final threat, it could be something line a genetically engineered "superbug" exploiting some inherent weakness in the "supergene". Alternatively, it could even be a natural event! For example, with your supreme scientific ability you could predict that 500 years from now on the Earth will be hit by a very strong gamma ray burst, and genetically engineer humans so that they're extremely vulnerable to the aftereffects or gamma ray bursts. First, everyone genetically modifies themselves. Then, almost everyone dies. Then you can step in and clear the remains on the civilization easily. [Answer] I'll go the genetic modification route but I'm not after deadly diseases. Rather, something very benign--one or more of the usual human gut bacteria. It continues to function as normal but produces an extra compound--one that mutates human DNA. If your distribution is detected it will be identified as a harmless organism and not given much scrutiny. Meanwhile humanity is plagued by cancer and birth defects. Next generation release another modified gut bacteria, the problem goes up. Eventually the human race can't maintain reproduction, you succeed. Another option would be a compound that causes asexuality. Humanity goes extinct due to a lack of reproduction. If you don't mind taking out most of the animals also add another compound--one that causes paranoia. Someday humanity will take itself out. ]
[Question] [ In my world a Magic High Nation is fighting against high tech level Nation about the same level as one of the nations in our world. I'm trying to decide what sort of magical creatures can replace a modern air force and make the magic side able to stand up to Modern military weapons. Note: The conflict will be mainly a guerrilla war in forested, mountainous environment with some spill over into the cities. As a guerrilla general fighting for the magic side, I can only afford to choose two magical artifacts each of which will give me power over one of the two magical creatures below. Which combination of creatures would be most effective in closing the gap against a nation with a modern air force? List of magical creatures available: 1. Dragons * Size: equal to that of a large dinosaur. * Speed: dragons use magic to help them fly and can move very quickly through the air about 1/2 as fast as your average jet plane. * Firepower: Dragons use elemental magic to breath fire, elemental fire can easily melt stone and steel. * Powers: Dragon can go into hibernation when not in use so you don't need to keep feeding it. * Intelligence: A little lower than that of a human. 2. Griffins * Size: Somewhere between a horse and an elephant. * Speed: Magic assisted and almost as fast as a jet plane. * Powers: Lion level strength, bite that will transform victim into a griffon on the next full moon. The effect is permanent. * Firepower: Sharp teeth and claws * Intelligence: slightly below human 3. Phoenix * Size: Three meter wing span. * Powers: can turn into a fire elemental during the day. * Speed: as fast as a regular fighter jet. * Firepower: Elemental fire on the same level as dragons. * Intelligence: bird level by night, greater than human by day. 4. Gargoyles: * Powers: Made of stone, but only active at night must remain unmoving for the day. * Speed: magic assisted and about 1/4 as fast as your average jet plane. * Size: twelve feet tall when standing up straight. * Intelligence: equal to that of a human. 5. Unicorn * Powers: Provides healing for its rider and short range teleports but is unable to directly hurt a living creature. * Intelligence: Beyond human. * Speed: magical assisted and slightly faster than a jet plane. [Answer] I'm going to say right idea, but wrong creatures. Modern warfare by high tech military forces is based extensively on the identification of targets and the precise application of force. You can see how low tech armies and insurgencies deal with this just by looking at the news. The best way to prevent yourself from being splattered all over the countryside is simply by not being visible to the sensors of the allied forces. Insurgents typically hide in jungles, or nowadays in the urban jungle, where separating them from the civilian population is difficult. Traditional high tech devices like thermal imagery and laser guided bombs are not affected in any physical way, but the commander cannot accurately determine if he has the correct target, or even if he does, must balance the ability to destroy the target with collateral damage to the civilian population and infrastructure. Large creatures like dragons, griffons and even unicorns are large and distinctive enough that they will be rapidly identified, even in dense urban environments, and can be targeted by snipers or precision munitions, depending on the circumstances. Only the Fey people or shapeshifters will be able to successfully blend into the civilian populations, and they will be able to successfully evade the precision weapons, high tech surveillance systems and even (to a certain extent) human intelligence services tasked to find them. [Answer] # Puppies, Unicorns and Griffins *Note that this will only work once, but that might just be enough* It's well known that soldiers in the field are suckers for orphaned puppies so we're going to use this against them. The griffin bite is apparently non-species specific, so get your griffin to give a little nip to a puppy (or the whole litter), then the unicorn heals the puppy so no damage shows. Leave the entire litter of puppies somewhere sheltered near the enemy base and wait for them to be found and adopted by a patrol. Come the next full moon, you have surprise griffins in their base, happily chomping away on their sleeping soldiers. Time your frontal assault with this event. [Answer] Going through your list, the only thing that is as fast or faster than a jet is the unicorn and it can't even do any damage. Depending on your how your world works, raising a dragon or phoenix should take a long time so I'd imagine that you wouldn't have too many of them. Though their fire power seems top notch their speed would be a problem as the jets could kite them and I imagine that missiles and bullets would travel farther than their fire attacks. Gargoyles would be even worse as their speed is terrible, they would be used as an anti personal force that sneaks in under cover of night to kill troops and then flees. If I had to pick a force it would be griffons and unicorns (can't believe i said that). I'd use the griffons to turn all captured enemy soldiers and use the artifact to control them, there by making a massive overwhelming force. I'd then use the unicorns to heal the griffon swarm as best as they can. Only hope would be to fight a battle of attrition. [Answer] Since this is about guerilla tactics and not open combat, this is not about what works best against the enemy's aircraft. Worst case scenario the attacking force is discovered and enemy jets are scrambled - the attacking force then has to escape. The **Gargoyles and Unicorns** are your best bet. Gargoyles are great for night raids on enemy positions, and the unicorns (I assume OP means teleport instead of "heliports") can make for quick in and out surgical strikes, before escaping at speed, healing to keep casualties to a minimum. (They only serve as transport for a team of soldiers). If the enemy mobilizes during a raid the unicorns will be able to get the team out to safety, read to raid another day. [Answer] With no way to really compete with modern aircraft I would use dragons and gargoyles. Once the planes are in the air you have to seek cover rather than fight s losing battle. Using the cover of night you can blitz attack the enemy with the dragon and gargoyle force to hopefully cripple whatever aircraft you can find before the planes can launch. [Answer] **Strategy** Destroy the enemy completely, by exhausting and terrorizing the humans. Gargoyles provide protection. Griffins try to create griffon army by biting. **Operations** Gargoyles can be dispersed through the forest. They look like stones during the day, so they can be sneakily everywhere. The humans must destroy either every stone or be really scared. During nights the gargoyles provide tank like protection for griffins. The animals that move at speeds comparable to jets (I think that this is pretty unplausible) are so fast, that they can easily reach the enemy camps. At the camps it is hard to destroy gargoyles, as you would need explosives. Griffins then come and bite as many humans as possible. The humans will then need to execute the victims, which has a huge effect on their morale. When it's close to full moon, they can also capture bitten humans to get more griffons to be used in attacks. [Answer] First of all, you mean a Pegasus. A Unicorn cant fly and it will never fight. I would choose Dragons. I Think that they cannot be harmed by machinegun fire and maybe they are movable enough to avoid air-air-missiles. Dragonfire will be deadly to planes and other war machines, including tanks. And according to Terry Pratchett, the can travel at sonic speed by blasing dragonfire under their belly. [Answer] Griffons and unicorns are probably one of your best bets. What you want to do is get the griffons to bite as many enemy combatants, or neutral parties as possible. The limitation of the predictable full moon means that quarantining a griffon plague is far easier- unless you can bite and spread the gift before you transform. One viable tactic might be to create clinics that heal people with unicorns, but ensure that everyone is passed out or entirely sedated the entire time. Then, before you heal them, have the griffons bite them. If the griffons don't need to be told that they're on your side, this might prove to be highly effective. If you are unable to sedate them, just say that the healing process hurts a lot, to convince them the bite is a normal part of it, and keep them blinding for similar made up reasons. Direct force isn't what you want to get at here, so being creative with the unicorns and griffons is probably one of the best approaches. [Answer] There really aren't many good choices there. Modern military strategy depends on the precise application of force, and an important part of that is identifying targets. Dragons, griffins, phoenixes and to an extent unicorns don't really hide that well, and a phoenix would light up every sensor within a kilometre (given that it's a flaming bird with a 3 meter wingspan). If you have to choose, gargoyles are your best bet. They can hide under the jungle canopy, they're stone, so there's no heat signature, and although they're a bit large, they could evade the military well enough, I believe, assuming that they are careful (i.e. if one pretends to be a rock it had better not move until it's sure it isn't seen and it had better go back to the exact same spot in the daytime). [Answer] The three which sprang to mind before I read the list were all undead related. Vampires for their sagacity and ability to infiltrate buildings. They can also use mind control allowing them to turn enemy personnel into their pawns. Ghosts for recon. Zombies for attacking enemy supply lines and bases. They can walk under water, require no supplies, can be used similar to mines in laying a defensive perimeter. Lay them just below the surface where they can rise once the enemy walks over them. They could even be fitted with explosives or poisonous gas for added effect. From those listed I'd choose phoenixes and gargoyles. Phoenixes are fast and can burn supply columns and patrols. Assuming they're classic phoenixes then if killed they produce an egg to replace the creature lost. The danger there is that the enemy could get the egg and then use these creatures against your own forces. Gargoyles are night fighters. Deadly hunters at night, during the day they're undetectable as they appear as rock. Con is that the naked eye would spot them and the enemy would take a policy of destroying every statue it found. Best bet during the day would be hiding them in a building or cave, lying flat perhaps to make their identification more difficult. [Answer] Given that you haven't specified the amount of protection that any of your creatures have I'm going to assume the highest level of armour I've ever seen on a dragon in a fantasy setting; 18 inchs of natural scales that are "as hard as steel" and wearing, and flying in, articulated full plate armour that "makes their natural armour seem a pale thing by comparison" and go with dragons, dragons and a side order of dragons. Very few weapons in our modern arsenal stand a chance of damaging what is effectively a flying titanosaur wearing a nuclear hardened bunker and by the time the ones that can are deployed the damage will be effectively total. ]
[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/54082/edit). Closed 7 years ago. [Improve this question](/posts/54082/edit) One day, all friction ceases to exist on earth. While I'm sure that the occasional sliding coffee would annoying, life on earth would change. However would this mean the end of mankind? Would there be any survivors? [Answer] **In short:** You can make it disappear, but friction will take a large part of physics, all of chemistry and microbiology with it when it goes. This could be an interesting fantasy world, but you definitely wouldn't find anything which works as you are used to. No humans, animals, plants, Earth-like planets, not a sun which works the way ours does. You could invent something very abstract and alien and explore it from psychological, sociological, etc angles. **Long answer:** Friction can't disappear. There is no physical law you could change to make it disappear. Friction is not a natural constant or something, but a consequence of the very way our world fundamentally works. Friction is basically like gear wheels skipping teeth. Everything has a rough surface to some degree (because it's built from atoms and molecules), so when you rest two surfaces against each other those irregularities interlock like the teeth on the gear wheels. This keeps surfaces from sliding against each other. When you put too much work into making them slide, they slip out of each other and start skipping *over* each other. If you want to make friction disappear you need to build up completely new physical models from scratch, ditching the whole atom->molecule->macro world structure and substituting something which is not based on little particles so it can be *smooth*. I think some ancient Greek philosophers had some ideas like this, maybe look at those. Essentially the world would consist of homogeneous blobs of matter (which stay homogeneous no matter how you look at them, this likely implies that they can be divided infinitely for example). Once you got such a model there is probably a parameter which you could tune to add/remove friction. If created very carefully, a large change in friction over a shorter than evolutionary timespan *might* not kill *everything*, but such a live-configurable model would be multiple times more complicated to construct. In both cases: Creating such a model in a reasonably self consistent if not very detailed way would probably take a team of natural scientists months if not years. So you'll be doing a *lot* of hand waving (and still have to think very hard) and unless (or even if) you've got a very good general knowledge of the natural sciences anyone trained in any natural science will still casually spot problems in your model. You would be reinventing almost all of science's models for everything on the microscopic level and would probably have *lots* of trouble if you want to keep the macroscopic world similar to the one we know. Then, you still keep a lot of friction like effects. Those are sometimes also called just friction, but they work completely differently and I consciously decided to exclude them for reasons detailed below: 1. Fluid drag: You probably know that fast moving objects in an atmosphere, like cars, bikes, trains and planes spend most of their power overcoming "friction", once they are at speed (so are not accelerating and not moving very slowly). This is not true. Overcoming friction is a small part of the power they need and it becomes smaller as vehicles move faster. They spend their power *moving air out of the way*, accelerating that air. This is not friction, this is inertia. This directly is Newtonian motion. You've got multiple possibilities here: a) You accept this. b) You ditch Newtonian motion and if you do that, stuff gets *seriously* weird. c) You construct your model so that the predominant "gas" in the atmosphere behaves like a super fluid which *probably* solves *part* of that problem but raises a whole load of other ones (for example concerning the organisms which maybe still do something like breathing). If you want a model with parameters which you can tune from "friction" to "no friction" without killing *everything* in it, don't do it. 2. Macroscopic friction: Using an other physical model for the world you could claim that those small irregularities which I previously explained stop existing, so friction disappears. But this would just be friction on a molecular level. When you have macro level (*visible*) irregularities, like on asphalt roads and tires, then those would still show some (greatly reduced) "friction" effects. You couldn't properly drive a car anymore, but it would probably not slide over asphalt as over ice. You could still walk (especially barefoot, clinging to irregularities in the ground). Assuming something like vehicles and humans still exists, which as mentioned is not easy. You could try to remove that kind of friction too, but this would mean that all of your world would need to be smooth on a macro level too. And once one macro level is smooth, you can always go one more macro level up, until everything is just one huge round blob and no world remains. That said, if you are very good at explaining just a few reasonably easy things and hand waving the whole complicated rest in a way which doesn't make scientifically inclined readers cringe, then this could lead to a very interesting, novel fantasy world. [Answer] Yes, everyone would probably die. Without friction you can't grip against the ground so if you try to walk you will fall you will slide without stopping until you hit an uphill. At that point you will decelerate due to gravity and them slide back down. You will slide back down and along until you hit another uphill. You will then pendulum up and down the two hills until you eventually stop by hitting something like a wall. Everyone will end up either at the bottom of walls, rocks or holes or sliding around. Unable to move and slowly dying through lack of water or dying from broken bones. [Answer] If earth suddenly lost friction we'd all die in massive earthquakes and tsunamis as all the pent up tectonic energy everywhere is released at once. But after that we'd never have an earthquake again since now the plates are perfectly lubed. Not that we'd be around to care. Don't worry, the mud slides will give us a proper burial. [Answer] I suspect a whole bunch of biological functions will go haywire, because they are designed to operate in the presence of friction. Chewing, how bones and cartilage move against each other, how food passes through the gut, how blood flows in your veins, and so on. [Biotribology](https://en.wikipedia.org/wiki/Biomechanics#Biotribology) is apparently the study of friction in biological systems. And here's a paper which discusses [friction at micro and macro scale in living things.](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4168876/) [Answer] Things get very difficult. Everything loose slides downhill, trading potential energy for kinetic energy as gravity accellerates it downhill, then goes uphill on the other side, being slowed by gravity converting kinetic energy back into potential energy until it slows to a stop and starts sliding down again. With no friction, pebbles, sand and soil grains slide freely like a liquid. so all the beaches run down into the depths of the ocean. No more beaches. And plant cover doesn't help - soil or sand particles can flow out between the roots if there are big enough gaps and its downhill. If not, then the rest of the sand/soil just runs out from underneath. With no friction at all, I suspect things will work like a giant newtons cradle (remember those? a set of balls in a line where an impact at one end sends the same number of balls bouncing off the other end of the line. The only damping factor would presumably be where distortion from impact turns some of the energy into heat - but does that need friction between atoms? I have this vision of beaches sliding into the sea only to come sliding back out on the other side of the ocean (or maybe more likely bouncing back when the sand hits the sand from the other side...) Picking things up is hard - unless there's a closed loop handle, or a bulge above on something you can get your hand more than halfway round, they'll just slide away. If you manage to pick up a slanting sided glass, don't squeeze to hard or you'll overcome the weight from gravity and squirt the glass out of your hold. There is nothing holding nails, screws, nuts, or bolts in place, except gravity. Any downward facing nails fall out. Any downward facing nuts, screws, or bolts unscrew and fall off or out. Anything else just has some of the weight of the nail/screw holding it in place, so that's not going to be good either - any noticable force pulling outward and out it comes. You can't walk anywhere - you're sliding, and can only exert a force perpendicular to the surface you're on. And there are no brakes. Given enough advanced warning, you could probably set something up to allow people to function = an environment with lots of grab handles, so you can move around from handle to handle (Though you may end up penduluming if you only hold on to one). hydroponics (or a sealed tub to stop the soil floating away - though the soil would act like a liquid anyway) would let you grow stuff (though you'd need tools to catch and handle seeds. Eating might be challenging... [Answer] Well first, on the macro scale, we have cars. Without friction, cars will not be able to gain or lose momentum, this means two things; one, all emergency vehicles cannot help people and two all currently moving cars will not be able to stop. An benefit is the remaining existence of pressurized movement, which will allow most technology and (most importantly) the biological technology to go unaffected, so your heart will still pump blood. Do not think this means that you will be fine, sound will move much faster as their is much less friction to slow it down; it may go fast enough to make every sound worthy of a sonic boom, every living thing on earth will likely go deaf. Basically what we have is the removal of the main method of decreasing momentum, all that can stop an object is gravity and interference. This means all planes will be left to die as will all people in elevators. Luckily opposite force (a la newtons law) is not effected, so walking is unaffected. With this we have our answer; anyone, anywhere in a moving object will likely die, I would estimate that this at least half the population (though I suspect much more) Will this cripple humanity? yes. Will they be unable to restore the world as they once knew it? Absolutely. Will everyone die? no, there will be hundreds of millions of survivors, all scared, in pain and confused. ]
[Question] [ ## Context When hit by sun rays, the moon creates excess energy, it increases the energy & reflects it back to earth as mana rays to make magic possible (the exact process is not important). Most of it quickly vanishes into the atmosphere if not used or stored. I imagine mana to work similar to light, but capable of being temporarily "absorbed" by matter like heat to make it linger on earth for practical reasons. Magic users(about 5% of the population, but dependent on the nation), gods(not literally, but practically just immortal wizards in this context) & some animals & plants can store it or use it for spells, ranging from changing the environment to healing, creating magical artifacts, etc. Unless magic users receive extreme amount of schooling, they are only really capable of very limited feats like creating sparks or dubiously helpful lucky charms. It takes more than a lifetime of commitment to use more than the residual mana left inside ones body. ## The (potential) problem In the process of creating mana, the moon breaks the [first law of thermodynamics](https://en.wikipedia.org/wiki/First_law_of_thermodynamics). Gods (and very talented humans) can also imitate this process, although the amount is limited by the mana they can utilize(equivalent of 1 TWH for gods, 1MWH for humans), the meager results(10-20% increase) and the effort it takes(a day for maximum amount). The reverse is also possible under similar rules, but doesn't see much use. I also assume creating/destroying matter with energy is practically impossible to [avoid the world filling up over time](https://worldbuilding.stackexchange.com/questions/209504/how-do-you-avoid-running-out-of-space-due-to-magically-created-objects) without adding new rules. **What possible problems could arise from such a system for breaking the laws of thermodynamics?** [Answer] There are zero problems with your idea. Here's a simple solution that doesn't violate the laws of thermodynamics: All energy originates in the sun, as it does in real life. However, if that is the case, how could the moonlight in your universe be a special mana-containing light when sunlight isn't? Answer: Some of the energy from the sun is invisible. For real-life examples, consider UV and infrared light, radio waves, etc. The sun is emitting all of these all the time. What happens when you shine UV light at something fluorescent? It glows (appearing to create energy out of nowhere). The energy WAS there already in the form of invisible UV radiation, but you can see it now. So, the moon's rocks are special. When sunlight hits them, a handwavium process equivalent to fluorescence occurs. This converts invisible energy from the sun into mana-containing moonlight, which then shines onto the Earth. [Answer] # A candle in infinite darkness Breaking the laws of thermodynamics isn't necessarily an end of the world scenario. I would compare it to having an identical universe as we live in, with one single candle on Earth that burns on nothing and outputs extra energy. It breaks the laws of thermodynamics, but if all it can do is add this pitiful amount of energy, it doesn't change anything in the grand scale of the universe. At least not to the lives on Earth. Adding magic that from your story sounds limited in nature doesn't need to change anything. Sure they add some energy here and there, but even the Earth is massive in comparison. It'll radiate the resulting energy sooner or later, having an energy equilibrium of intake and output insignificantly higher than before. ## Make a good story Let's say the above isn't true. Let's say the magic absolutely destroys the laws of thermodynamics and would destroy the world in a month. Why would you write about that? It's a story about magic. There's already some suspension of disbelief. It'll stretch a bit further. Implement it in a way that looks scientifically plausible, or do not mention it at all. A quick example are the books if "A song of ice and fire", better known from the first book title "A game of thrones". Most of it is rooted in a world from late medieval periods we all understand. Yet it has seasons that can last years. How would most creatures survive a 3 year winter without stockpiling food as the humans need to do? Not to mention dragons and other magical creatures. The point is not to talk about how it's possible, but that a good story will not have you question it. [Answer] ## Frame Challenge: It doesn't need to be in defiance of thermodynamics. ### The Courtship of the Moon and the Land When the Sun's rays strike the Moon, they bounce off towards the Earth to create Moonlight. The Moon sends her love along with those reflected beams in the form of mana, which is absorbed greedily by the Earth, who cares as little for the Moon's love as it does for the scraps mages and gods use up for themselves. But the Earth is sloppy in her greediness, and so when the Sun's rays strike the Earth and bounce towards the Moon as "Earthlight", the scraps and the refuse of the Moon's gifts are carried back to her as "hollowed mana" that has little use to mortals since there are no mortals on the moon. This dance has carried on for thousands of years, the Moon pouring her love into mana, the earth sending it back wasted, and mortals benefitting from the excess, and it shall carry on for thousands more, but the gods fear the day that the Moon's love runs out, or that she turns her eye towards another, for how then will they maintain their power? ### Or, in scientific terms: The mana system is a closed loop between the Earth and the Moon similar to the water cycle, where mana bounces back and forth without ever changing in amount, carried along by reflected light and restored to full power by the reaction between the moon's surface and the sun's light (because, uh, magic moon rocks contain handwavium). When a mage uses a spell, after the effects are finished, the mana used in its casting is hollowed out and eventually makes its way to the moon to be refilled. [Answer] As others mentioned, you don't have to worry about this, regardless of the mechanics of your mana. Consider, for instance, sugar. Sugar is stored sunlight. If it becomes adequately ubiquitous in an environment, then creatures will start using it as a primary energy source, taking it from creatures that make it. Those creatures turn the sugar into heat. Every time a lightning bug puts 50k volts through its prey, the heat of electrical release will go into the environment. If the environment receives a surplus of heat, it radiates into space long before it can build up. Burning our coal reserves is an excellent example of this. Coal is sunlight that was captured hundreds of millions of years ago. The heat released from the coal isn't meaningful in the planetary heat equation, even if the CO2 blanket is. Mana from the Moon would be no different. If it builds up, it's because nothing has evolved to use it. The more it builds up, the more likely that something will evolve to extract it from the environment and use it metabolically or effectually. Thus, the only reason you'd have thermodynamics issues is if you purposely write them into your world. [Answer] **The moon doesn't need to reflect the sunlight** > > And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so. And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And God set them in the firmament of the heaven to give light upon the earth, And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good. > > > (Gen 1:14-18, KJV version) The sun and the moon are simply described as *lights in the firmament of the heaven to divide the day from the night, to give light [and magic] upon the earth*. In your world, the moon may be a source of light on its own. The moon doesn't need to reflect the light of the sun. It could be a floodlight set up by martians in the moon. Or a spaceship. The sun and the moon could be giant lanterns that get switched on and off every day. [Answer] **The sun just moves the mana from the moon** Lore says that in the old days, a number of powerful wizards/gods created the Moon to move around the Earth. So, the moon is part of the Earth that was magically put into the space in an old age. *(They could have done that asked by a king, for their own glory, to remember a glorious event, to jail an enemy/devil there, because they wanted to see in the night...)* Also, we don't know the origin of *their* magic (was it *floating* on the Earth? it exhaled from a volcano? it could be extracted from some <materials> that are no longer available now? we just don't know). **The Moon was moved into orbit by magic,** and magic is -according to some people- moving it through the space (a potential contradiction to Newton's First Law, although we don't know if the moon of your world varies its speed, or corrects its route like satellites do), others think the magic around it is a field intended to protect the moon (or its inhabitant?) from meteorites/visits/escaping, and finally others think it's just residual magic from the orbiting act (on the Earth it would quickly disappear, but there is no atmosphere in the Moon, so it may stay there, trapped by the Moon's gravity field). This large amount of magic/mana in the Moon is slowly being eroded by the sunlight. And when the sun rays reflect there and travel to the Earth, they carry a bit of that in mana form. [Answer] Short idea: the moon reflects sunlight (so you're not violating any laws of thermodynamics), but there's some special magical part of the moon that laces it with mana. ]
[Question] [ Is it possible without magic? Just like our world's rivers, but instead it's a river made out of milk. [Answer] No. Milk is an immensely complex mixture of fats, proteins, and carbohydrates, to provide a complete diet for an infant. These compounds are created in nature solely by living creatures. Even if one posited a single-cell creature that happened to match these proportions when it died and broke down, it would be impossible to concentrate it sufficiently; the environment would be all the creatures, and no food for them, and then the river would sweep them away into more water to dilute them. [Answer] Not milk as we know it, no. Mary gave a good definition of milk, and following it the only way to have milk rivers is to have some kind of very strange giant creature that excretes a river of milk its young swim in. Fun idea, maybe not quite fit for every world and would also require some weird evolutionary pressures to evolve. But if we consider any white-ish liquid that contains fats, proteins and carbohydrates and is basically nutritious to count as milk, we might have some options. I agree that the compounds in milk are pretty much only made in living creatures. But a river could, for example contain (micro)organisms that secrete nutrients into the water, which might be bacteria (as Renan suggests), algae, even plants or animals. It's still a very unlikely adaption and you need to consider that not only would this dilute, it would also go bad in the sun and probably attract all kinds of other lifeforms to feed on it. [Answer] > > Is it possible without magic? Just like our world's rivers, but > instead [a] river made out of milk > > > Not naturally as others have already said. The only suggestion I can make is that an old civilisation created a vast food-producing factory. When they were wiped out, the factory kept on making its products. Milk, being the only liquid one, eventually spilled out of its tank and started flowing down the hillside. All the solid food containers filled up and became blocked so the factory diverted all its resources to making milk. For this to continue there must be a huge automated farm somewhere. Instead of cows, there would be genetically engineered "teats" that are constantly supplied with the necessary nutrients from the farm. Fish have adapted to live in the milk but they have evolved to become blind because it's impossible to see through milk. They don't need vision because all their food comes from the milk itself. [Answer] I thought this: a fictional species that is a "hybrid" between amphibian, reptile and mammal that needs to be in water as a cub (like an amphibian), but can live in dry environments as an adult (like a reptile). After gradual changes in the biome to a desert, those who could still reproduce were those who could create their own small ponds for their young. The liquid produced would be milk to provide nutrients for them (like a mammal). Many of those amphibian-reptilian-mammal in one place create a large lake that overflows into a river (depending on the terrain relief). They could live in groups and then those who produce more milk help those who produce less. Probably these rivers would be temporary, forming only during the mate season. But if each group has a mating season at different times, but they happen always in the same place (similar to sea turtles), perhaps the river could be constant (with one group coming after another). Edit: another advantage of doing this is to attract prey, because they would stay for a long time looking after the young and would not have time to hunt. [Answer] Other answers point out that the creation of such a river is highly implausible. Rivers displace a lot of liquid, it would take a huge energy investment to produce enough milk. What does the organism get in return? It'd have to be a by-product of a huge, localized process. Probably the only energy source is the Sun, so maybe a weird kind of photosynthesis? But even if it existed, I think it wouldn't last long. Such a huge amount of easily available nutrition would quickly attract some bacteria or other lifeform that feeds on it. Which would keep multiplying until most of the nutrition is extracted close to the source. [Answer] ### No This has been somewhat covered this already, but I wanted to add some thoughts, especially after reading some of the other answers hypothesizing ways that such a river might be plausible after all. A dairy cow, which has been heavily bred for maximized milk production, produces a peak of about 15 gallons/day of milk (a more realistic number is a bit under half this, but let's be optimistic). If we consider a sizeable herd of 1,000 cows, that's 15,000 gal/day, which sounds like a lot, right? Well... if you do the math, that works out to a bit over 10 gal/min. A "good" faucet (or, let's say, a garden hose) puts out about 2.5 gal/min. A fire hose can be up to 500 gal/min. That means that 1,000 cows can produce a continuous flow of milk equivalent to... 4-10 garden hoses, or 1/50th of a fire hose. That's not much of a "river" by just about any standard. [Answer] ## **Nah.** **Well, maybe.** --- **Nah.** --- The previous answerers do a good job of speculating how this couldn't or could (with caveats) work. I'd just like to add some context with the real-world figures. According to [Statistica.com](https://www.statista.com/statistics/194937/total-us-milk-production-since-1999/#:%7E:text=The%20United%20States%20produced%20about,to%20around%20167.4%20billion%20pounds.), US milk production gives about 4,000 liters per second (though I may have made a mistake in calculation -- please tell me if I did!). In contrast, the headwaters of the very small Metolius River in Oregon discharges around 3,000 liters per second ([The Ore Bin, March 1972](http://ir.library.oregonstate.edu/dspace/bitstream/1957/3107/1/vol34_no3_ocr.pdf) [data within range]). So, all the cows in the US might produce a small river. But to put all [94.8 million](https://www.statista.com/statistics/194297/total-number-of-cattle-and-calves-in-the-us--since-2001/#:%7E:text=How%20many%20cows%20are%20in,cattle%20and%20calves%20in%202017.&text=There%20are%20over%20three%20times,living%20in%20the%20United%20States.) together would take an unimaginable economic and environmental toll on the area around. Heck, their giving the world an unimaginable toll on the world *without* being crowded together. As @Matthew also calculated, this is just not realistic. [Answer] Although animal based milk is probably a no go, how about plant based milk? Coconut milk occurs naturally and plant evolution for items like fruit is based on ways to ensure seed propagation via local consumption and excretion in a far away location by animals. Other plants simply have the seeds stick to the animal to be brushed off later in a far away location. If the above statements hold, it could be possible for trees to evolve in a way that they produce seed ridden milk they release into water in order to entice some creature to drink the milk and in so doing so either consume their seeds to be excreted later or have the seeds stick to the animal until they get brushed off at a later date. I would imagine this kind of tree would be in a mangrove like environment and its target is lifeforms that live in and around the mangrove. If this method of plant reproduction is highly successful then the mangrove would continue to grow in size and, what was previously highly diluted milk streams in a river, would eventually turn into a river of milk diluted by water. How far the river would stretch until all the various plants, animals and bacteria consumed the milk is a questionable proposition but it should at least be visible as a river of milk if you are near the source. If people don't think that a continuous river of milk is possible owing to the volume of water, have all the trees "bloom" (deposit their milk and seeds) at the same time, so you get a river of milk for a few weeks per year. Better propagation is a plus for evolution, so is it is quite possible that the milk evolves an anti-bacterial property like that of honey or egg white which would prevent bacteria from consuming it,thus allowing it to travel further in the river and attract more animals to carry the seeds elsewhere. In some ways, we are replacing aspects of fruit and wind based seed distribution with water based distribution, so the trees being an area with little wind, few flying insects/birds and lots of water makes sense. One caveat is that this is technically not a river of milk. It's a regular water based river upstream from the mangrove that becomes heavily poluted with milk in the mangrove and then slowly returns to being water based as other lifeforms consume the milk. Given the common proximity of mangroves to the sea, it is possible that it might stay as a milky river until it flows out into the sea but that would be down to the author. [Answer] How human-like can insects get before you call what they do "artificial" rather than "natural"? I envision a **city-sized insect colony**. The individual insects are very dumb and tiny, just like on Earth, but the colony as a whole is much larger and smarter than any insect colony on Earth. Just like some Earth insects farm fungi, these alien insects farm mammals and milk them regularly. Somehow they worked around the relative size issue. A river of milk flows from the structure where they milk the mammals, as a simple means of transporting it within the colony. ]
[Question] [ **This question already has answers here**: [How would humanity enter a Dark Age?](/questions/9307/how-would-humanity-enter-a-dark-age) (29 answers) Closed 5 years ago. I am writing a post apocalyptic story in which a large amount of the foliage is dead and agriculture has become much more difficult. My original idea was to say that this was caused by an ancient nuclear war or climate change, but these have both been done a million times. Are there other possible ways that humans could inadvertently or purposefully cause major disruption of the food chain? One idea I had was blocking out the sun as in the Matrix, but what would cause this/why would someone do this? This could be one major cataclysmic event or a gradual change in the environment over the course of thousands of years. [Answer] Pollution of water. Majority of the world's photosynthesis is done by algae.[link here](https://www.nationalgeographic.org/activity/save-the-plankton-breathe-freely/) There is less oxygen, chemicals and micro particles in the air. Sealife is almost gone and the surviving fishes are dying from the plastic micro particles from degradation of plastic. Whales are dead. Nature could fix this, since having less photosynthesis means there will be more CO2 to process, so more algae would grow back once the chemicals will stop killing the algae. You could add some toxic or acidic rains to get the calamity inland. (The chemicals are evaporating along with water) [Answer] One possibility that hasn't been explored all that much is [Volcanism](https://en.wikipedia.org/wiki/Volcanism). Volcanoes are one of the world's largest producers of greenhouse gases, and they produce more of these than man does with industrialisation. This is one of the primary arguments of climate change skeptics, although a discussion of this issue is outside the scope of your question and therefore won't be undertaken here. My thoughts on this though are that if you had a new mining technology that allowed you to extract minerals from the crust at deeper and deeper levels (or you simply need to do that as you're depleting minerals near the surface at a faster rate) then it's possible that you could destabilise the crust. The Mantle (the large section of the earth between the core and the crust) is very hot, molten rock and other minerals that also seems to be under quite a deal of pressure under the surface of the crust. If you dig enough holes that are deep enough, you can weaken the crust to a point where you can encourage more volcanoes to erupt out of mine shafts. I should state that this is not likely to happen with modern mining tech, but a near future state may make something like this possible. If we're not careful in such a scenario, we could punch through the crust just a little too far and generate our own volcanoes. This could cause massive greenhouse based climate change on earth. It would be pretty destructive for humankind especially, but agriculture would also be affected quite substantially, at least in the short and medium term (geologically speaking). The good news is that igneous rock eventually breaks down into very mineral rich soil, actually *improving* agriculture in those areas. This is in part why there are so many settlements near volcanoes in the modern world. So in time, if mankind can get through the intervening periods, plant life would likely thrive after such a cataclysm. Of course, your real problem in that case would be diversity as many different species of food plants would be hard to come by. It should also be pointed out that such mass volcanism would also have an immediate side effect for human civilisation; it would immediately (and more or less permanently for the current generation) ground all aircraft as the volcanic ash in the air literally destroys aircraft engines in flight. This would make the trading of any existing plant seeds and varieties even more problematic. Of course, humans would have a harder time surviving this scenario than plants would. The only saving grace would be that most mines are not around highly populated areas meaning that at least you wouldn't lose too many cities to magma flows. That said, there would be immediate food production concerns in many countries, and given that all global transport would be limited to surface based, this could cause the kind of global apocalypse you're looking for through pure starvation. Of course, after the first few 'artificial' volcanoes erupt, you'd hope we'd stop drilling deeper holes, but then sometimes we as a species are just not that bright. Ideally, you'd want to be living in a poorly mineral resourced country with plenty of high ground in some form of farming village if you want to survive this. That of course also limits your availability to tech, but that's a matter for your story world rather than the kind of apocalypse that has caused the world being set. [Answer] A new "miracle pesticide" that's completely non-toxic to humans is invented, and is quickly adopted worldwide. Unfortunately, as it accumulates in the soil it *slowly* starts to interfere with the [nitrogen cycle](https://en.wikipedia.org/wiki/Nitrogen_cycle) - with the plants unable to absorb nitrogen, they start to die out. This wouldn't be *quite* so bad if not for the fact that the reason it happened so slowly was because the chemical leeches through the groundwater into rivers/ponds/oceans, evaporates with the water, and comes down in the rain - meaning that **everywhere** is affected, not just the locations where this pesticide was used. **{EDIT}** *As a pesticide, this also kills all of the pollenating insects world-wide, hastening the floral demise. On the plus side, no more mosquitos.* Plants fall, everyone dies. [Answer] * An antibiotic-resistant super-flu (or super-ebola) pandemic. * A plastic-eating bug, either deliberately developed as a biowar germ or natually developed in some landfill and then spread. * A hack of a very widespread IoT device kills the internet. A few hours after the food supply chain breaks down, humans almost everywhere riot and thus prevent any orderly restart. It goes downhill from there. [Answer] Destruction of the [nitrogen cycle](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1247398/). Nitrogen is essential for plants and animals, but it is fairly unreactive, making it hard to use in nature. Through fertilizers and pollution mankind is putting out enormous amounts of reactive nitrogen which can be used extremely easily by plants. One way we can see this changing the environment now is in increasing fertility throughout most of the world. > > "In the Netherlands, for example, extreme reactive nitrogen levels > have changed the Dutch countryside’s characteristic heathlands to > grasslands." > > > This doesn't sound too bad, but when this reactive nitrogen hits the oceans it is disastrous. The influx of phosphors and nitrogen causes [algae blooms](http://www.fao.org/docrep/w2598e/w2598e06.htm), which choke out most other life in the area. This has caused dead zones along the Gulf Coast and other areas that stretch for hundreds of square miles. If this goes on the most productive parts of the oceans will be algae filled muck. > > In their summary of water quality impacts of fertilizers, FAO/ECE > (1991) cited the following problems: > > > · Fertilization of surface waters (eutrophication) results in, for > example, explosive growth of algae which causes disruptive changes to > the biological equilibrium [including fish kills]. This is true both > for inland waters (ditches, river, lakes) and coastal waters. · > Groundwater is being polluted mainly by nitrates. In all countries > groundwater is an important source of drinking water. In several areas > the groundwater is polluted to an extent that it is no longer fit to > be used as drinking water according to present standards. > > > Also plants can only absorb a limited amount of nitrates. Once they take their maximum limit the remaining nitrate doesn't remain in the topsoil. > > As with water and air, reactive nitrogen builds up in soil. There’s a > limit, however, to how much nitrogen plants can use. When soil reaches > a point at which plants can’t use additional nitrogen, it’s said to be > “saturated.” And saturated soil, in theory at least, will shed any > additional nitrogen introduced to it. But that nitrogen doesn’t leave > unaccompanied. “When it leaches out of the system,” says Townsend, “it > takes other nutrients with it, so it ends up acidifying the soil, and > it takes things like magnesium and calcium out into the water. And you > end up with a very unbalanced system.” > > > Another problem is that reactive nitrogen causes a whole cascade of problems in the atmosphere. > > But as nitrogen levels continue to rise, Townsend says, the net health > effects become increasingly negative. Furthermore, says Galloway, > reactive nitrogen can not only impact many different ecosystems, but a > single atom also can make mischief repeatedly, unlike most better > recognized pollutants. “If you put a molecule of NOx in the atmosphere > from fossil fuel combustion or a molecule of ammonium on an > agricultural field as a fertilizer,” he explains, “you have a whole > series, or cascade, of effects that goes from acid rain to particle > formation in the atmosphere, decreasing visibility and causing impacts > on human health, acid rain, soil and stream acidification, coastal > eutrophication, decreasing biodiversity, human health issues in > groundwater, and nitrous oxide [N2O] emissions to the atmosphere, > which impact the greenhouse effect and stratospheric ozone.” > > > Even better, nitrogen damages the ozone layer at lower levels, and in the stratosphere it destroys the ozone layer. So on top of acid rain, increasing acidity in the soil and water, a cloudier sky and algae blooms, UV rays will be killing plants and animals. So while it is a greenhouse gas, and far worse than CO2, changing the climate a degree or two is the least of the problems of an out of control nitrogen cycle. The earth will survive, but the food chain will be in tatters, plants will have to deal with intense UV rays, acidic soil and water, and agriculture will be very difficult but not impossible. [Answer] A malfunction in a solar shield, launched into space to filter some sunlight and thus lessen global warming, has left half the world permanently in the dark. [Answer] Paolo Bacigalupi came up with an interesting one petroleum shortages combines with widespread access to advanced bioengineering results in large scale ecological and technological collapse from poorly regulated genetically modified organisms. Including genetically modified humans, super crops and designer toy species, (for instance cat have been driven extinct by designer cheshire cats) make it your own by choosing your own species and designs. An easy one would be something that drives bees extinct, as a huge number of our crops , as well as a large number of plant species period,rely on bees for pollination. Another option is a genetically engineered plague released by a terrorist group, kill enough of the population and civilization will collapse on its own. Make it an extremist animal rights group for fun irony. [Answer] Depends on what tech level we're talking about, but to go a little near future, I'd suggest an asteroid mining accident. Some large, near-Earth asteroid is being exploited for the burgeoning space industry, and an industrial accident alters its trajectory just enough to make it hit the Earth with an extinction-level (or near-extinction level event), so we do to ourselves what nature did to the dinosaurs a while back. Since you clarified that we're talking about before we colonize other planets, it should be easier to arrange the accident (or "accident") - space mining would probably still be focused around Earth orbit, the most efficient way being to drag the asteroids into a high Earth orbit of some kind. Someone makes a minor miscalculation, a thruster malfunctions, or even a malicious actor does it on purpose, and we get an extinction-level event instead of a source of minerals near Earth orbit. As an added bonus, without lots of inter-solar-system traffic, it's much more plausible that there's no way to stop or redirect our impending doom. [Answer] Collapse of the phosphorus cycle in the biosphere - all phosphates are leached out into the ocean while mineral sources are long since used up. Plant life is increasingly stunted with no way of getting phosphates to the fields in a large-scale way. See <https://en.wikipedia.org/wiki/Phosphorus_cycle> [Answer] Automatic war machines gone mad: Nobody remembers who won the war, but the automatic, solar (fusion?) powered drones still wander the skies. The ones with missiles and bombs stopped working ages ago, but the ones designed to fight the biological war still wander on, filling their deadly poison reservoirs from somewhere (or synthesizing material from the sea with nanobots or whatever). Last vestiges of humanity defend themselves with whatever old AA-guns/-missiles they have left. A huge plant and/or insect poisoning storage facility might wait somewhere across the mountains for destruction and salvation of the local populace... [Answer] Over-population. This would create a demand for extra housing while, at the same time, creating an increased demand for food, putting more pressure on agriculture. Both housing and agriculture would increase the demand for land, competing with each other to secure and use it. Natural resources would decrease as a result and the need to increase food production would industrialise and intensify the process, more pesticides, more genetic modification. Natural pests become more resistant to pesticides, but cultivated strains of plants become modified to become increasingly toxic, the toxicity being removed by subsequent processing to turn into safe edible food. Toxic plants, however, cannot be contained and are soon growing wild, out-competing natural varieties (which will be more palatable to wildlife) decimating the ecology. The bees somehow survive, but their honey is toxic to anything else. The cultivated land is toxic to anything but the genetically modified crops. Result, a fractured food chain. Maybe rats breed prolifically enough and fast enough to withstand a high mortality rate while evolving as necessary, but higher mammals cannot. The rats compete with man for available food resources. [Answer] Cut food chains (probably combined with food shortage) People are terribly efficient on destroying other species. Some deliberately, some through a pollution (and I don't mean just a literal waste, but also light pollution, radio pollution and sound pollution all affecting other animals and changing their behaviour to the level that might cause a speciocide). We're already facing a problems of decreasing number of bees that is probably going to cause a serious drop in available food. Of course people will eventually find a way to replace it with technology but it goes far slower than the extinction of species. If this accumulates on more species and add increased number of people and reduced natural inhabitable environments for other species we might end up in a situation of a very severe food shortage with most sources of food extinct or polluted. Combine that with the problem that most food production ways are water inefficient causes this resource to become scarce and you have a nice apocalypse. The worst thing is we might be actually heading in this direction somewhat undernoticed. [Answer] One of the largest problems in the world is Climate Change and environmental impacts, what if the problems became too bad for our world and a group of scientists decided to genetically engineer a bacteria that would rid the world of fossil fuels by breaking them down chemically. This could also go into multiple variations, as in you could do an economic meltdown thus the food distribution is down, chaos would take over as electricity in various countries becomes the new gold or a war on the few remaining fossil fuels left. After an amount of years the bacteria starts to mutate and starts breaking down more materials not just fossil fuels. As fossil fuels are carbon based, as well as most things in this world, it will start with plants and insects and keep going on from there. This is just an idea. Thanks for reading. [Answer] The [Carrington Event](https://en.wikipedia.org/wiki/Solar_storm_of_1859) was a coronal mass ejection that hit the Earth. If it happened today it could cause significant damage to electricity distribution systems. Without electricity our civilization is dead in the water, and much of the equipment required to build replacements is also dependent on electricity. For ideas about the immediate aftermath you might like to watch [Episode 1 of "Connections"](https://archive.org/details/james-burke-connections_s01e01) by James Burke (BTW, note where he is standing and the flight number he mentions. Spooky!). Of course this is not an original idea, and the people who look after our electricity systems have put some thought into what to do about it. But there is no way to test those plans... [Answer] Accidental explosions something of the sort near major fault zones such as Yellowstone would definitely cause some bad scenarios at least around some parts of the world. An aerial chemical spraying malfunction could cause a lot of death to flora and fauna. Overpopulation is a more gradual problem that, if left unsolved, could cause revolutions, wars (not necessarily nuclear, but still devastating), and food shortages and the destruction of much of the landscape to try to make way for farming. If there was a year of drought during this period then many people may die of starvation and be unable to tend to remaining crops and much of the earth's surface that had been cleared for farming would turn into a wasteland. Just a thought. [Answer] The absolute worst-case runaway global warming, leading to a re-run of the Permian mass extinction. The (non-fictional, if somewhat speculative) book that you need to read about this is titled "Under a Green Sky", or Google that phrase. If this is the case, it is not going to end well for the human race or for most other species. However, the time-scale on which it would unfold is long compared to a single human lifetime (though very short by geological standards). There will be a window during which life remains possible. You will have to choose whether the characters in your story know that they are living in the end times for the human race with no possibility of reprieve, or allow them ignorant hope that things may get better for their children while dropping a bombshell on your readers. (Yes I know you said you don't want global warming, but I don't think I have seen this worst-case scenario explored in fiction, where the atmosphere is turning toxic and the oceans will soon be ringed with dying fish trying to breathe the air because the water is even worse. Too gloomy? ) [Answer] First, a mutation allows crabgrass or a similar infestant to spread with even more abandon, threatening not only gardens but crops as well. Second, a very specific catalytic herbicide is synthesized in ever-growing amounts to keep the infestant under control. Being catalytic and long-lived, a small dose will defend an area for a very long time. And finally Nature's sleight of hand - the molecule at the heart of the herbicide turns out to be a [disappearing polymorph](https://en.wikipedia.org/wiki/Polymorphism_(materials_science)#Disappearing_polymorphs). Almost overnight, the specificity of the herbicide turns into a curse for every kind of grass and most other vegetables, and plants start to die (not unlike John Christopher's *Death of Grass*). What plants succeed in adapting don't fare too well, and that's the scenario you described. ]
[Question] [ Utopias and utopian ideals are abundant in fiction, but they're often either fuzzily-explained or not *actually* functioning utopias. As a premise, I was wondering if some mode of compelling people to share their experiences and perceptions would be a necessary prerequisite for any utopia to work. It doesn't really matter what the technology is behind it: a hive mind; a magical system that switches people's consciousness between different bodies on a daily basis; some kind of modern technology that requires people to upload their own perceptions and experience others'... By obliging people to experience what others do (with full perception - sight, sound, smell, emotions, etc.), surely there would be no room for mercenary behaviour or narcissism? It would be very difficult to implement such a system, but if we're talking about a 10th generation of this system, where this is simply as ordinary a part of existence as breathing, can you see any immediate reasons why this wouldn't work in a utopia? **Slight edit** What if it *weren't* compulsory? If people had the ability to (mutually) agree to share perceptions, would that get any closer to achieving a utopia? (Perhaps with an exceptional case made in court hearings or something??) Imagine going to the doctor unable to articulate exactly what was wrong, and having a medical professional understand exactly what was happening to you. Or (maybe idealistically) being able to offer a wealthy politician a more full understanding of what life as a working class individual? Hopefully that would still encourage individuality and freedom of expression, while also helping to soothe some voices of dissent ("you just don't understand!!") by actually allowing them to communicate how they feel. (It's really helpful to see the kind of problems that this utopian/dystopian society would run into - and see if there are any problems that can be worked around.) [Answer] Yes, creating a unified sense of self across all of humanity does seem to be one way of achieving "utopia". I'm just unsure you understand the implications of the former. People wouldn't simply be experiencing each other's perceptions as if they were watching an educational movie. They wouldn't simply think to themselves "huh, I never knew what hardships being a terrible person caused other people, i'll stop my bad behaviour now!" and go on with their day. Rather they would *become* each other. People wouldn't stop being narcissistic because they'd learned their lesson. They would stop being narcissistic because their former sense of self would vanish, "they" wouldn't exist anymore. So don't imagine that in this "utopia" everybody will be super kind and sweet to each other as we interpret those elements today. In fact it's almost certain that if you visited this utopia, you'd see things which you probably associate with dystopia: a bunch of seemingly vacant, voiceless and willess "people" that have no personal drives, personalities or opinions: essentially just cells of a much larger super-consciousness. Now it's entirely possible that this super-consciousness might be very happy and thoughtful and virtuous. Just don't expect to see any of that by observing the bodies it is made out of. [Answer] Some people honestly enjoy others' suffering. All that compulsory experience sharing would do is intensify existing issues. A sadist would simply get a stronger "fix". A serial killer would get a fuller sense of his victims lives slipping away. The rapist would gain a stronger sense of power by experiencing the victim's helplessness. Another question is that this does not address is physiological deficiencies that express themselves "socially". For example, scarring on the corpus callosum can result in the physical inability for a person to experience emotion (called [alexithymia](https://www.ncbi.nlm.nih.gov/pubmed/17354075) ), which leads to an inability to process many normal social signals. While this might enable physiologically normal people to experience what the alexithymic does, the converse would not hold true. [Answer] Compelling everyone in a society to share the experiences of others, might bring about a commonality of purpose and thought generally, but would that be Utopia? Maybe society might change in this way, but what would happen as a result of this, I feel, would be a loss of individuality with all experiences shared. Will people be willing to share their life experiences? If all your experiences are shared, what of your life is truly yours? And will everybody view shared experiences in the same way? Will everyone want the same experiences? Unless we all become very similar in nature, experiences enjoyable to one person can be very unpleasant to another. Do we want that commonality? Putting everyone through the same life experiences may be illuminating, but the simple compulsion element will be a form of imprisonment - forcing experiences upon people who do not want them. Some experiences are unpleasant anyway - punishing, even. Is it fair to punish others unnecessarily, simply because one person has had a very nasty experience? One person with PTSD is bad enough, for example, but can that society care for that one person if everyone must experience it, and possibly develop it? I cannot see it working. = = Edited for making it non-compulsory = = If it were non-compulsory, people would choose who they wished to share experiences with. To a certain extent this already happens - people gravitate to others with similar interests and similar outlooks naturally. Being able to actually share experiences by some emotional link, seeing things even clearer through another's eyes would reinforce those bonds - but these are people who already share interests and probably outlooks. More cliques develop, society becomes more segregated, there is a tendency to form groups each, assisted by the mind-link, polarise forming common opinions of other groups. Society becomes more unequal, less fair, less like utopia - though some may like it, others will not. Perhaps you randomize the sharing, but then it starts to become compulsory, again and, another consideration, if you are spending so much time in another's life experiences, how much time do you end up in your own, and how will you know it is yours? [Answer] I suggest you watch the movie "The Circle" with Tom Hanks, it taps exactly in this type of "Utopia", and the problems it poses when you start invading the privacy of individuals. A good read about this if you really want to dig deeper into "transparency" is "The Transparent Society" by David Brin. In any case, it seems that it could be a good idea to enforce transparency "in the public area" (both in the "public space" for private people and overall for "public-serving entities"), whereas it is mandatory to maintain privacy in the private sphere. Nowadays, "privacy" as such is never really there even in your "private" sphere, as we communicate through electronics that can be hacked/tapped very easily and data can be collected with or without you even being aware of it. And if invading your physical privacy is required, there are many (and growing) means to do so, from searching your garbage to letting a nano drone fly in your private home. :) The concern here is that while "transparency" is often asked for civilians, it is rarely required for the leaders (and I'm not only speaking about politicians). Nowadays, on the contrary, private companies thrive on confidentiality, so if you would like to enforce "transparency" on them, I wish you good luck, especially given their overall lobbying power. Until then, any privacy you give up as an individual is all to the benefit of the very ones who are in positions that are strong enough to demand strong secrecy in their offshore bank accounts and their "confidential competitive data", to mention a few. [Answer] Forgive me for saying so, but your question sounds like the kind of thing my highly liberal friends would both suggest and honestly wonder why anyone wouldn't think it would work. The premise is usually along the lines of, "if you understood how your actions hurt others, you'd be disinclined to act that way." Thus, shared experiences would make the world an utopia. There are at least three truths to remember: 1) The average person may even believe they would want this, but when forced to admit the necessary consequence of no privacy whatsoever, suddenly they would realize all the vices that would result in embarrassment on the low end and abject terror on the high end. We have all made mistakes and may even continue to do so, but to air all that dirty laundry? What such a world would soon realize is that the average person pretty much always feels some kind of pain — and it would be impossible to make all of it go away. > > You can please some of the people all of the time, you can please all of the people some of the time, but you can’t please all of the people all of the time — *John Lydgate* > > > 2) Everyone has different desires (healthy and unhealthy). What happens if my healthy desire conflicts with yours (much less my unhealthy desire... but theoretically that's what you're trying to fix, isn't it?)? Will our shared experience lead to understanding, compassion, and charity? Or is it more likely to lead to jealousy, frustration, and depression? All people generally believe they have obtained some level of competence. What happens when shared experiences prove that what we thought we were is much more than we actually are? All to often, that quiet little illusion is what allows us to live our lives with contentment — to be proud of the work we've done. How utopic does the lowest person on the totem pole feel? Would shared experiences mean we're all pigeon-holed into our "place" in life? Would it remove ambition? What happens if someone deisres to start a new business only to realize due to shared experience that millions of people think it's a bad idea? What if those millions of people were wrong? Our current social media experience is far too close to what you're looking for already, and look what happens? Sometimes that instantaneous reaction is right and exposes evil. Sometimes it's wrong and hurts people badly. Shared experiences are simply the ultimate form of social media — meaning it's the ultimate form of making mistakes. > > Managers rise to the level of their incompetence — *[The Peter Principle](https://en.wikipedia.org/wiki/Peter_principle)* > > > 3) Finally, there are the inevitable psychopaths and sociopaths in any society. Most live their lives without causing a horrendous amount of pain, but some don't. What happens when our shared experiences reveals them for what they are? Is it even fair to subject everyone else to what such people have done and how they think? Is it fair to subject anyone to the pain felt by the victims of such people? How is society benefitted in that case? And what does it do about it? If the price a utopia must pay to be a utopia is to execute those who *cannot* fit into the utopic ideal, is it still a utopia? (It obviously isn't for the pychopaths and sociopaths.) The bottom line is that utopias cannot exist so long as anyone is willing to hurt another, willingly or not. They cannot exist so long as anyone is forced to live a life contrary to their desires. They can only exist if everyone who thinks differently than you do is excluded.... That wouldn't be overcome by forcing (or not forcing) anyone to experience anyone else's lives/emotions/perceptions/feelings/reality. [Answer] After reading the question, I contemplated a couple methods of implementation in order to consider the pros and cons. I will state them below, followed by the reason I don't think any of it would matter in the first place. ### 1. Replaying a random person's day as another person's dream In this method, some sort of technology or magic or what have you records the lives of every person within the system and replays the full experience for another, randomly selected person. The replay really could occur during some type of cultural event; say a scheduled stop at a centrally controlled location or some sort of ritual. I just thought the dreams thing was neat. * Pros: + Everybody shares in everybody else's lives in a fair manner. By that I mean, assuming the system is maintained a truly random, then everybody gets to experience every aspect of life, without significant bias. + Assuming this is controlled by a central source and since the experiences occur as dreams, it is simple to explain away strange occurrences as "bugs in the system". This allows bad experiences to be taken with a grain of salt, and allows good experiences to be bolstered through a sort of confirmation bias. * Cons: + Random selection can spread mental illness from bad experience during formative years by doubling the occurrences of these events; once when they actually happen, and once when they get passed to someone else. + The second Pro from this list could be reversed and negative effects could be unintentionally reinforced while good effects are explained out. + In a truly random implementation, it is likely that a bell curve will exist where a small percentage of people get almost only positive effects, a small percentage of people get almost only negative effects, and most get some combo of both that end up cancelling out anyway.### 2. Selective Experience Sharing My thoughts behind this system are based on the assumption that those that govern or lead other people have the largest overall impact on society as a whole. This could be government officials, company CEOs, you name it; anybody deemed important enough. Intentionally targeting those people to share the experiences of others would be a way to have the largest impact for the smallest effort. In this system, when a person comes to some sort of power they would undergo some sort of process of taking in the experiences of others. Perhaps, for 182 days leading up to their inauguration (duration possibly depending on the impact of the office they are going into) they exist as an observer only in the body of a random person for a week at a time. Or, perhaps each day is a time-lapsed version of another person's last 6 months. * Pros + As mentioned, this is a bang-for-your-buck approach. High impact, minimum effort overall. + Allows the higher ups to see the struggles of the every-man. + Allows the vast majority of people to maintain their sense of self. * Cons + Does not give the less impactful people a way of seeing what it is like to be important and powerful. + Does not reduce slow shifts in cultural norms at a grass-roots level, focusing on more of a top-down approach. ### 3. Why none of it matters One of the things we have to remember here, is that our experiences as humans, and our emotions and such, are stored in our bodies as a path of neurons and the electrical impulses and chemicals that they contain and transfer. While there are those of us that have unusual patterns in those connections, most people are wired pretty similarly. What this would mean is that, excepting a very targeted approach in the implementation, far-and-away the most experiences that end up transferred will be pretty dull and unimportant and if we are continually assaulted with those that are not, our chemistry will likely either find a way to normalize, making the most extreme occurrences seem uninteresting, or it will become much more extreme, giving everybody a sort of universal PTSD. Either way doesn't sound particularly fun. [Answer] Utopias are such because they are very nice ideas that go against what is our ingrained instincts. All tentatives to go in that direction inevitably find some "unexpected" side effect frustrating the purpose. Your Utopia is no exception. Even allowing there's some way to do what you propose (currently there is not and we have no idea if and when that could become feasible (likely answers are "no" and "never")), the first problem that comes to mind is: "who controls the process"? Any system can be controlled, hacked, has backdoors or, simply is governed by some humans; who will prevent the generic Joe Programmer to rewire system to put himself (and, possibly, some friends) into the wealthiest bodies that are around? Even admitting the system is perfect and really randomizing, how can a society work when people is swapped around and a medical doctor is inhabited by a woodcarver or a priest? Even if you manage to sort out such problems there remains the ultimate: nobody would have the *reason* to work hard and you would get a mass of [Socialist Workers](https://en.wikipedia.org/wiki/Soviet_working_class) with no real push and no real future. Sorry. [Answer] Not all people experience empathy or have a conscience. Sharing experiences would not affect them and, in fact, they might actually use it against you. Psychopaths (or sociopaths) being the prime example. You might say then. Well, what if we could *fix* these people? The answer is, apparently, that these type of people are necessary to an evolving society. > > * The Sociobiology of Sociopathy: An Integrated Evolutionary Model. Linda Mealey. 1995. > * Antisocial personality disorder: An evolutionary game theory analysis. Andrew M. Colman and J. Clare Wilson. 1997. > > > ### An example Imagine a world where no one lies because everyone experiences the pain caused when another is lied to. Everyone trusts everyone and is happy. Then, one liar evolves who can lie without pain (the prototypical psychopath). Think of the havoc this person would cause to that trusting society (picture said society with Hillary or the Donald suddenly appearing). People, then, apparently evolve to have a certain amount of distrust and to produce a certain amount of psychopaths to generate that distrust. And, a kind of equilibrium is reached for society and the species. My engineering background leads me to believe that a utopia is always and necessarily a type of [critically damped system](https://en.wikipedia.org/wiki/Damping_ratio). It may exist for a short period or as a steady state (i.e. so long as nothing at all ever changes). However, any perturbation in the system - no matter how small - and the utopia is gone. ]
[Question] [ Imagine a spaceship entering Earth's atmosphere, it has lost control of its engines and is relying on its reverse thrusters to decelerate before crashing into the Pacific ocean. So in an attempt to save everyone on board from an impending doom, the pilot turned off all the reverse thrusters located on the top of the ship while diverting all powers to the thrusters located at the bottom. I was wondering would making the spaceship skips on the ocean surface be much safer than dropping straight into the water as gently as possible? In many sci-fi blockbuster movies spaceship were seen skipping on solid ground and the pilots emerged out with a smile and often suffered minor superficial cuts. If skipping increased the survivability then all future spaceship pilots are required to perform this manuver before they are licensed to fly. [Answer] It doesn't really make sense to talk of "forward engines" and "reverse engines" for a spacecraft. Use maneuvering thrusters to orient the ship, main engines to change orbit. As long as it is not in the atmosphere, the craft can reorient to fly backwards, sideways, or upside down. So the question would be more like this: **Can the RCS engines be used to control reentry?** The [Reaction Control System](https://en.wikipedia.org/wiki/Reaction_control_system) in real-world spacecraft is sometimes considered a backup to leave orbit. This would take a *longer* burn since they are individually and collectively less powerful, and there could be problems if the RCS uses different fuel with a lower Isp. The heroic piloting would not come at the last second before splashdown, it would come in orbit when the pilot calculates the best deorbit burn using limited engines. [Answer] Horizontal velocity only helps if your craft is aerodynamic. Consider skipping stones across a lake. The best skipping stones are flat and wide, like a wing. They're not round like a ball. Flat stones sink a little into the water, maybe a few millimeters, and because of their shape and velocity, the water applies lift to the stone. It picks up vertical speed and flies back into the air. The same is gonna be true of your spaceship. If it is relatively flat and wide, it might skip like a stone. And that would help a little. But the problem with this, is that if you don't land perfectly level, your tail will hit first. This will torque your craft's nose down, hard. The faster you're going horizontally, the harder your nose will torque down. It could easily be hard enough to destroy the ship. If one side hits first, you tumble, and again you could easily destroy the ship. If the nose hits first, the aerodynamics actually hurt you. The aerodynamic forces will pull the ship down further rather than bouncing you back up. In summary, if you can land very nearly perfectly level, it will help a little. If you can't land totally level, you die. Seems to me that keeping a high horizontal speed is more trouble than it's worth. [Answer] Train your space pilots on gliders. First, spacecraft must slow from orbital velocity. This is done either using the atmosphere, or if the atmosphere is too thin such as Mars or the Moon, they must use engines. Once that's done, most real spacecraft entrusted with human lives land using parachutes. This is simple and safe. There are a handful of space planes, the space shuttle and X-37. They have wings and landing gear. They land as unpowered gliders on a long runway. Parachutes. Landing gear. Wings. Runways. All of these are missing or from your typical sci-fi spacecraft. Sci-fi spacecraft are often bricks lacking even basic wings (think Star Trek shuttlecraft) and land vertically under raw power. Yet in an emergency they mysteriously glide. Since this is tagged science-based, we'll ignore these magical flying bricks. Real flying bricks which can only land safely under raw power would never be rated safe for humans. --- Let's say you have a sensible space plane which is capable of gliding. Its been slowed by the atmosphere, but finds itself still going way too fast. Power is out. What's the pilot to do?! Deploy their parachutes. > > What if there are no parachutes? > > > It's a glider, so it can trade velocity for altitude. Keeping the nose up retains altitude while shedding velocity. This gives the pilot more time to declare an emergency and reach a *runway* or highway to land *on its landing gear which has wheels*. If no suitable runway is available, they look for a flat, open space. This could be a field or water. In a field they may decide to land with their landing gear down, but in water they will land with wheels up. They will dump any remaining fuel and other flammable material to reduce the chance of fire. "Skipping" will not help. Sci-fi spacecraft made of unobtanium make great gouges in the landscape as they bounce which would tear a spacecraft apart. Instead, the pilot will endeavour to land gently with as low a sink rate as possible. They will keep the nose up to avoid it digging into the ground and flipping the craft over. If all goes well, the craft will gently touch the ground. It might bounce a few times. Eventually it will skid to a halt. Hopefully no fires will start as a result. [Answer] If you are in the unfortunate situation that you have to [lithobrake](https://en.wikipedia.org/wiki/Lithobraking) a spacecraft which wasn't designed for that, then you want to make sure you have as little kinetic energy as possible on impact and that you lose that remaining energy as slowly as possible. First, you want to minimize the speed with which you hit the ground. This can be achieved by entering the atmosphere in a very shallow angle. That means you spend more time in the atmosphere and lose more kinetic energy to atmospheric friction. You also lose that energy in a much more gentle way, so the risk that your spacecraft gets torn apart during atmospheric reentry is reduced. The planet *does* have an atmosphere allowing you to aerobrake a bit, does it? If not, you are even more screwed. But it doesn't change anything regarding wanting a shallow angle. When you impact the ground (or the surface of the ocean, which behaves pretty similar at such speeds), you really don't want to lose all your acceleration at once in one big splash. It would create an enormous sudden acceleration force on the ship, which would be pretty destructive for the craft and for any of the unlucky lifeforms in it. "Skipping" means that each "skip" only loses a small amount of kinetic energy. Dividing one large crash into many smaller crashes means that each of these crashes is far more survivable. Even better if you can somehow get such a shallow approach that you can "slide". "Sliding" means that you lose your kinetic energy relatively slowly though friction. Also, that friction will be concentrated on the surface you are sliding on, and that force will act parallel to it. Most of the impact energy will be used on shaving off the lower hull and the lower decks of your spacecraft. Your upper decks might survive relatively unscathed... ...might... Good luck, you are going to need it. [Answer] **Moses maneuver** As your ship nears the surface, they open fire with everything they have. The ocean surface is blasted into steam and droplets as the ship plunges in. Weapons blazing they carve a path through the water, turning the water ahead of them into steam and droplets. The ship is slowed by the steam and droplets and frank flames (superheated water vapor) rushing past them but not slowed with a sudden shock as would be the case for an impact with water. The tunnel through the water that they make collapses behind them. By the time they reach the bottom they are barely moving. Space captains: despite historical gravitas the Moses maneuver remains strictly theoretical. [Answer] Short version: skipping turns your crew into paste, simply smashing the water has the best chance of success (not much though). Just imagine you have a perfect rock to skip across the water. To skip it you have to throw it forwards across the water. Upon skipping it'll decelerate its vertical speed and accelerate upwards again, maintaining its horizontal speed much longer. Now throw the stone with a lot of vertical velocity as well. You could still skip it but it would require more velocity horizontally as well... which would do nothing to save the crew. In fact it would kill them faster! If the ship simply smashes the water and sinks deep down it'll decelerate over a longer time than if it smashes the water and skips. Now imagine crashing a space ship at mach something velocities into the water. The ship will take a larger hit if it skips than if it simply drills itself into the water, and that is ignoring the fact that you now need to decelerate a much higher horizontal velocity as well. Now if you can convert the vertical velocity into horizontal velocity it works, as then you have a much longer time to decelerate the same velocity. I hope you've got wings and the time to change your angle! [Answer] I highly doubt that a spaceship would be designed to withstand a touchdown with water and nearly terminal velocity. Already for airplanes that's not a design consideration/validation. And skipping on water would be even more harsh on the structure. If you are extremely lucky the spaceship won't crash on water in the attempt to skip, but I don't think it will be usable after the event without major repairs. [Answer] Skipping means all the downward impact energy of splashdown is redirected upward. This means MORE stress on your ship causing more damage than it would have taken if it had broken the surface immediately. However it still might be a good idea to add some horizontal speed if you can use it to have more air push your ship up before the impact with water or land, (IE if you have wings to gradually convert downward to horizontal force, or you can add enough horizontal speed that the curvature of the planet drops the ground away from you.) Another reason to try to skip your ship could be that it's effectively invulnerable, and has inertial dampeners so the extra impact force is less important than not sinking before the crew can get out. ]
[Question] [ Inspired by comments to [JBH's answer](https://worldbuilding.stackexchange.com/a/118210/756) to [The worlds between, the consequences of instantaneous FTL](https://worldbuilding.stackexchange.com/q/118208/756). ### The Premise A technology for instantaneous travel exists, making it possible to travel to any point within our galaxy. Travel time and cost are equal and are not affected by distance. The teleportation devices can operate equally well in space and on the surface of a planet. ### The question Under these conditions, is it better (easier, faster, cheaper) to mine asteroids or planets? [Answer] One thing to consider is the difficulty of retooling. This is, oddly, a point in the favour of asteroids. Simply put: when moving your operations from one planet to another you have to consider differing atmospheric conditions, gravities and temperature constraints. You might have to completely redesign your operations to cope with anything from crushing pressure to acid rain. When mining in space you’ve already engineered for hard vacuum and presumably varying degrees of sunlight. You are (paradoxically) much more in control of the environment and so can simply pull up stakes and move without needing surveys in advance. As an example: consider the extra complexity you would have to build into a Von Neumann probe (self replicating space probe) in order to allow it to deal with planetary conditions vs just harvesting asteroids. [Answer] It depends on the cost structure at the moment when you place this. **Mining Asteroids** Pro: * easier to move large masses due to lower gravity * easier to locate interesting resources Cons: * heat management in lack of atmosphere * difficult to hold position in low gravity * work in space suit **Mining planet** Pro: * heat management in atmosphere * work with re-breather possible Cons: * move loads in high gravity * mining prospect needed Once you have an idea of how much can each of the cons cost to be covered, you can determine which is the best option. [Answer] I think that if such technology was available it wouldn't make much sense to mine at all. The most profitable solution would be to have processing plants in planets with ideal conditions for each mineral and many gathering stations simply looking for the biggest/purest chunks of minerals floating in the galaxy that such factories can process without any mining involved. If travel time is zero the limiting factor is the processing speed of the factories, the difficulty of discovery of such rocks, and the cost of teleporting **Even collecting very small rocks would be more profitable than mining** If the cost of teleporting is high (lets say it consumes lots of energy) then you should take into account the cost of producing such energy, and compare it with the energy and time cost of mining. If energy is very cheap, even collecting dust over the galaxy would be more profitable than mining. [Answer] When you teleport something from place A to place B you have to compensate for various differences between the two locations. For example, the asteroid or planet to be mined will be moving in a different velocity (direction and speed) that the asteroid, planet, or space habitat which is the destination. In our solar system, the orbital velocity of Mercury is about 47.8725 km/sec and the orbital velocity of Neptune is about 5.4778 km/sec. When Neptune and Mercury are lined up in a straight line with the sun and on the same side they are traveling in parallel directions and the speed difference is 47.8725 minus 5.4778 or 42.3947 km/sec. At times in their orbits when they are lined up with the sun and are on opposite sides of the sun, they are traveling in opposite directions and the difference in their velocity is 47.8725 plus 5.4778 or 53.3503 km/sec. The velocity difference between two different objects in the solar system is constantly changing between minimum and maximum and also changing in direction. Also, all natural bodies naturally rotate. And all space habitats built by humans will be built as cylinders and made to rotate to provide simulated gravity on the inside of the cylinders, until and unless a method of generating gravity is discovered. And of course, the direction of rotation of a spot on or in a rotating body is constantly changing, and thus the direction of rotation of the minerals that are in that spot. Therefore the object that is mined and the destination of the minerals will have different orbital speeds and different speeds of rotation, as well as different orbital and rotational directions. And if the difference in total velocity is small enough, the minerals teleported in will bang around a little without doing any damage. But if the total velocity difference is high enough, the teleported minerals will do a lot of damage. And if the velocity difference is high enough, the teleported minerals can cause an explosion like an atomic bomb. For example, a stony asteroid about 10 meters (33 feet) in diameter entering Earth's atmosphere at a speed of tens of kilometers per second can create a 20 kiloton explosion - about equal to that of "fat man" at Nagasaki - in the air, and such airbursts are now known to happen about once a year. The energy in the Tunguska explosion is now estimated to be "only" equal to 3 to 5 megatons of TNT, and thus about 130 to 300 times the energy of the Hiroshima and Nagasaki bombs. It was caused by a small comet or a rocky asteroid about 60 meters (200 feet) wide traveling tens of kilometers per second relative to Earth. The extinction of the dinosaurs may have been caused by the Chicxulub impact of a body 10 to 15 kilometers (6.2-9.3 miles) in diameter traveling at tens of kilometers per second and releasing energy equivalent to 10 billion Hiroshima atomic bombs. So a method of handling the velocity differences between the departure point and the destination point is necessary when teleporting between different objects in the same solar system. Our Sun also orbits around the center of the galaxy with a speed of about 300 kilometers per second. A solar system orbiting at the same distance on the far side of the galaxy would have about the same speed in the opposite direction, and thus there would be a velocity difference of about 600 kilometers per second to allow for when teleporting objects from such a solar system to our solar system. In E.E. Smith's *Lensman* series starships can become inertialess to travel much faster than light, but when a starship turns off the inertialess drive and become inert again its original velocity - and its difference from that of the destination - returns. Thus careful maneuvering is required to prevent the starship from slamming into the destination planet at great speed and devastating the planet. This makes it very difficult to transfer even a single person or a much smaller object between two different space ships with different inert velocities, and it is used as a weapon by moving planets with inertialess drive, turning off the inertialess drive once they are in position, and letting their intrinsic velocities smash them into target planets. The *Lensman* series has some very big explosions. There is also the difference in gravitational potential energy between different objects at different distances from the center of gravity of an astronomical object. For example, objects that are higher on Earth have more potential energy than objects that are lower, because they could potentially fall farther toward the center of the Earth. An object that fell from an infinite distance to Earth would be accelerated to a velocity of 11.186 kilometers per second. And that is also the velocity needed for an object to escape from Earth's gravity - the escape velocity. The escape velocity from the surface of the Sun is 617.5 kilometers per second. But at Earth's distance from the Sun, the escape velocity from the solar system is only 42.1 kilometers per second. [Wikipedia Article](https://en.wikipedia.org/wiki/Escape_velocity#List_of_escape_velocities) [Space.SE question](https://space.stackexchange.com/questions/3612/calculating-solar-system-escape-and-and-sun-dive-delta-v-from-lower-earth-orbit) From the table, you can see that each body in the solar system has a different escape velocity, and each body with a different distance from the sun also has a different solar system escape velocity. Thus the total escape velocity from Earth and the solar system is 53.286 km/sec, and the total escape velocity from Pluto and the solar system is about 7.83 km/sec, etc. At the Sun's distance from the center of the galaxy, the escape velocity from the galaxy is about 492 to 594 km/sec. Thus the total escape velocity from Earth, the solar system, and the galaxy should be about 545.286 to 647.286 km.sec. And the potential energy of an object at a particular position should be proportional to the total of all the escape velocities at that position. So teleporting an object from one astronomical body to another should cause a significant change in the object's potential energy. So you should read Larry Niven's story ["By Mind Alone" (1966)](http://www.isfdb.org/cgi-bin/title.cgi?54152). And his article ["The Theory and Practice of Teleportation"](http://www.isfdb.org/cgi-bin/title.cgi?115990). Once you decide how your teleportation system will handle the differences in velocity and potential energy, you can then calculate those differences for various known and imaginary astronomical bodies and decide whether planets or asteroids would be better for teleportation based mining. [Answer] Both and neither, under those circumstances, all else being equal, you mine the richest sources of the target material that you can find regardless of source. All else may not be equal though, in particular planets may be worse targets because they: A. are more likely to have certain, dangerous, conditions like poisonous atmospheres or extreme gravitational conditions that make them harder to extract material from B. are worth more as is than as a strip mine, a world that is an Earthly paradise is worth more ecologically intact than it is to the mineral extraction industry. The only other note I would make is that multiple asteroids are better than a single planet of the same mass when it comes to the *rate* at which you can extract material because of the [cubed-squared law](https://en.wikipedia.org/wiki/Square%E2%80%93cube_law). But with the gravity of a world being a non-issue any rich source of a given element is an equally valid target economically. [Answer] If instant teleportation technology exists, such that travel between any two locations in the universe is equal cost, then planets are much easier to mine. Their atmosphere makes heat management much easier to work with, whereas asteroids require you to build large radiators to dissipate heat. Their surface gravity makes manufacturing significantly easier (note that somewhere around the gravity of our Moon or Mars is the optimal for manufacturing, but Earth-like is still much better than almost none. Most asteroids, on the other hand, have surface gravity measured in micro-gees, making manufacturing completely different. Planets have a lot more resources to mine than asteroids. Mars has 190 times as much mass to mine as an asteroid does, while the Earth has 1800 times as much. Earth-like planets can also give you free life support through plants replenishing your oxygen and making food. Obviously, this only applies to planets which already have life on them, so not all planets have this perk, but it's still worth thinking about. It is also much easier on people in a world which has significant gravity. Your asteroid miners will have their muscles atrophy and will have difficulty standing when they return home, unless the teleportation is cheap enough to use it for daily commutes. Even with only the Moon's gravity, it becomes much easier to maintain enough muscle mass to continue standing when you return to the Earth. While people have commented that planets are more likely to have dangerous weather etc., asteroids are perpetually dangerous. You have to lug along your own life support, always be careful that things don't go flying off into space, and watch out for several ton rocks moving on the order of millimeters per second crushing you. I'd argue that planets are safer. ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 9 months ago. [Improve this question](/posts/245031/edit) What would be a good reason for androids to have a need to eat and drink (not necessarily human food)? The human body requires food and water in order to refuel and sustain itself, but in the case of androids, you could make arguments such as: * Could they just have reactors with very long operation times? * Could they just plug themselves into a wall socket or some sort of generator? * Could they just drink gasoline? (lol) Androids in my setting are combatants that operate in the field, with minimal resupplies (an open-world game with survival mechanics), and I need some good reasons to transplant human survival behaviors onto them. [Answer] Androids eat and drink like humans, despite the inefficiencies, for several reasons: * One fuel source for both the humans and the androids, simplifying supply lines * Hiding from enemy forces which of your forces are androids * Encouraging humans to work well with androids by making them seem more human [Answer] This isn't a hard one. There are numerous things that an android might need to keep functioning. We already have fuel cell technology that can convert sugar into energy. This has been suggested as an alternative to batteries, but the tech is currently more expensive and less reliable. Something like an android, however, could readily extract energy from concentrated sugars. Water would be a natural method to keep the sugar in solution, and they could also use human-ish systems to purge leftover materials. Additionally, they might need to "consume" lubricants, hydraulic fluid, electrolytes, and even materials for basic maintenance and repairs. They might need a way to reload consumable resources. Having excess ports in a framework can be inconvenient. There's a good reason that most animals combine their in/out areas where possible. Self-cleaning mechanisms can be difficult to construct, so you don't want to have to have any more openings than necessary. Our stomachs and intestines are actually a complex chemical sorting mechanism. The android's sorting mechanisms could be a lot simpler, and it could shunt input to different reservoirs, but having a common port has its advantages. [Answer] # Androids are Versatile Why do we have androids in the first place? Why not just a moving arm on a trolley like that robot arm guy who is Iron Man's best friend? [![enter image description here](https://i.stack.imgur.com/wlvD4.png)](https://i.stack.imgur.com/wlvD4.png) Why not just a software AI with access to your files and internet? Like that yappy orange guy who is Iron Man's second best friend. [![enter image description here](https://i.stack.imgur.com/0oYaa.png)](https://i.stack.imgur.com/0oYaa.png) The reason is androids are versatile. They can do anything a person can do. Androids are used for jobs where new unpredictable tasks will suddenly appear. Tasks like, say, climbing a ladder or walking on gravel. Or licking an envelope. In line with versatility, the androids are fueled using the more available fuel source -- carbs and oils. The android might be needed somewhere with no power grid or access to gasoline. But that place probably has access to bread. Since otherwise, people would have no interest in it, and no reason to station the android in the first place. [Answer] Because human-fit food & drink is more readily available than specialized high-tech android fuel. You mentioned these are field combatants that don't get resupplied often. If supplies run out, then depending on your setting, foraging for berries and tubers may be easier than finding gasoline and compatible charging stations. Another thing, jumping off Mary's answer: > > One fuel source for both the humans and the androids, simplifying supply lines > > > Your androids were designed to eat human food because humans can't consume android fuel. If a squad loses all their android members, then leftover android rations become dead weight. [Answer] **Androids are synthetic, not robotic.** You're androids are synthetic lifeforms that were made in a factory, but are not pure robots in the traditional sense. They have organic components that require organic nutrients. For example, they may require organic brains because their creators haven't perfected AI, or because they required traits that cannot be reliably programmed such as empathy. Or because it makes them easier to integrate into a military run by people. The could also have brains that are cloned from experienced soldiers with all of their knowledge and experience because it's easier to copy from one organic brain to another than it is to copy from an organic brain to a machine. It could be that the enemy is simply really good at destroying robots using EMP weapons, or by hacking them, and by building organic androids wearing body armor, or with armored implants, you can make them less vulnerable to countermeasures. Or maybe people simply don't trust AI due to past bad experiences and so your androids are controlled by human brains grown in a lab with human feelings and emotions. If I remember correctly, Robocop needed food for his organic components, and his organic brain was considered superior to an AI one. [Answer] Pros of drinking fuel: * Way faster than plugging the android into socket and waiting for recharge. One gulp takes couple of seconds; same amount of energy transferred via cables might take minutes. * If needed, the android can also carry extra fuel. Sockets don't have this advantage. If some everyday stuff can be used as [emergency] fuel, the android can refuel itself even more easily when need arises. * Reactors need fuel, too, and there might be no such fuel that lasts long while providing enough energy to power the android without being heavy or potentially dangerous. If you can refuel easily, you save space and reduce weight and risks of accidents. [Answer] Androids are versatile in what sort of hydrocarbons they can derive power from, specifically for reasons of a survival scenario. It is generally easier to come by human edible hydrocarbons in the wild than refined petrochemicals or enriched radioactive material, after all. As for water, the androids can use evaporative cooling for heat management in hotter climates, or to reduce their thermal signature. This means they need to refill on water every now and then. ]
[Question] [ I know so called ''invisible ink'' exists in the real world. The most common types can be revealed either by applying heat to the paper it is written on (lightbulb, clothes iron, candle, lighter, etc.) or by holding a UV light over the paper. I wanted to know if one could make a so-called ''invisible ink'' that would only become visible under moonlight (I know moonlight is just reflected sunlight, but in case these is any ever so subtle difference) and if that is possible if such an ink could also be made in such a way that when it is removed from moonlight it would turn invisible once again. I fear this might be straight up impossible in real life, but I thought I might ask just to be sure. [Answer] **No** As said in other answers, moonlight is just attenuated sunlight, nothing more special about it. **But, actually yes...** Some materials exhibits a behavior called "[emission quenching](https://en.wikipedia.org/wiki/Quenching_(fluorescence))", meaning that the light that they emit reduces with an increasing stimulation, because the excited states in the molecule interfere with each other and make the relaxation (and subsequent light emission) more difficult. Since sunlight is more intense than moonlight, if your ink has a threshold for "emission quenching" which is lower than the sunlight intensity, such an ink might work. However, it would work not only with moonlight, but also with cloudy sky or artificial illumination. [Answer] **Short answer: no.** Moonlight is just sunlight, reflected off (effectively) asphalt pavement a quarter million miles away before it gets back to Earth. Magically, it's special in a number of ways, but scientifically, the only thing different from sunlight is it's not as bright. [Answer] ## No Any real property that moonlight has can be emulated with a suitable artificial light source. There's nothing special about moonlight or reflected light that applies outside a magical context. Just enchant it, fairly simple magic like that doesn't require a full magic system that's any use beyond the light show. [Answer] **[Frame Challenge](https://worldbuilding.meta.stackexchange.com/q/7097/40609): Real life is boring and frequently too limiting. What you really want is suspension-of-disbelief** And Tolkien's books, great as they are, require a lot of suspension-of-disbelief. But that's the point of fantasy, right? (I'm assuming you're pulling this question from the moon letters in *The Hobbit.*) And when we open the door to suspension-of-disbelief what we get is an ink that will only be visible with *limited light.* Unfortunately, we can't limit it to just moonlight because moonlight and sunlight really are the same thing.[[1](https://astronomy.stackexchange.com/q/26780/18065)] But we could limit the exposure to *light the same spectra as sunlight,* meaning if you have weak enough sunlight the ink would appear but light from a flashlight that wasn't specially designed to mimic sunlight wouldn't do it. And if you wanted to filter direct sunlight, you'd need to do it in a way that preserved the spectra (e.g., holding sunglasses above the letters wouldn't do it because common sunglasses only reduce a limited spectra of sunlight, not all of it). So we're talking sunlight at [0.25 lux](https://aapt.scitation.org/doi/abs/10.1119/1.2341814?journalCode=pte). How could we explain that (knowing that we can't do it at all in Real Life)? The molecules of *blue diablum 25,* a fluid manufactured by the Azure Dybbuk Corp., align in an opaque lattice at approximately 0.25 lux. Below that the lattice relaxes into a random form that is effectively transparent to the human eye (but not necessarily to a microscope!). Above that the lattice changes to a wholly organized and completely translucent way. This isn't detectable by a microscope. Of course the problem with using a microscope at less than 0.25 lux is that the human eye doesn't have enough light to see the result anyway. Very hard to detect without direct chemical processing, that *blue diablum 25.* [Answer] **Yes**, one could manufacture a reason why this would work in a universe similar to ours (in non-laboratory settings). But, **no**, for the reasons that others have pointed out, it’s not possible in real life. One thing others have overlooked is that moonlight is *not* merely dim sunlight; the sunlight has interacted with the moon rocks, and nonlinear or filtering processes could have taken place. So... The mechanism is a mineral which occurs naturally on the moon’s surface, but on Earth it is confined to the core and inaccessible in any meaningful quantity. This mineral has a unique spectral emission line in the ultraviolet, labeled $\Xi$, which is remarkably narrow for a solid-state material. This material absorbs bright visible sunlight via multi-photon absorption and subsequently emits this narrow line of UV light with a purity and brightness unparalleled on Earth except in a synchrotron or a specialized laser lab. Enterprising chemists have discovered/invented a molecule, $\Gamma$, which is unique in its complementary absorption line, $\Xi^\*$, leading to broadband visible photoluminescence upon excitation by moonlight. But most remarkably, $\Gamma$ has a long-lived alternate electronic configuration, and the absorption of light with energy even a fraction above $\Xi$ is sufficient to bump $\Gamma$ into this quasi-stable state, which is dark (i.e. no photoluminescence). Over the course of a few microseconds, $\Gamma$ relaxes to its ground state by non-radiative means, ready for excitation once more. Thus, broadband excitation leads to orders of magnitude dimmer visible luminescence compared to excitation directly at $\Xi$. You could probably image a message written in $\Gamma$ in your lab using a bright UV lamp, some specialized filters, optics, and a fancy electron-multiplying CCD camera (but it won’t fit in your pocket!). Then, as a practical matter, there are simply no easily accessible sources of light which have a narrow enough emission at the ideal wavelength to excite photoluminescence in $\Gamma$ without quenching it with higher-energy light. None, that is, except the moon. [Answer] Not exactly what you thought, but maybe. Two types of fluorescent ink, one is very sensible and it is used to write the words. The other less sensible is spread on the page as a background. If the text is exposed to the sun both inks become bright and the page turns into a bright white sheet with no discernible writing. If the text is exposed to the weak moonlight then only the sensible ink becomes visible. If the text is exposed to a candle in a dark room it won't work, either the candle is too far to trigger some fluorescence or too close and works like under the sun. A candle with a translucent screen in front might work, but nobody thought about it . [Answer] Yes, in principle Apparently the spectrum of the moon is actually different from the sun - slightly shifted to the red. And that leaves open the option for a complicated molecule that changes color when light of several different intensities at different frequencies falls on it. Of course, this would still be foolable by something that could reproduce the same spectrum. <https://astronomy.stackexchange.com/questions/26780/why-is-moon-light-not-the-same-color-as-sunlight> [Answer] ### is it possible to build moonlight recognizer? (yes\*) Another way of looking at this is can you build a device that can give probability of 'is this light that is being observed from the moon'. That would be in terms of spectrum and magnitude. That is this assumes the moon has a unique spectral fingerprint. Imagine: A computer, a few optical sensors and a display. That with those items a person could then display a message upon pointing the sensors at the moon. But such a system is not close to invisible ink. I would argue: yes such a device can be built. The problem: \* There will be false positives and false negatives. To reduce the false positive and false negative rate it would essentially require a computing device. Or many small devices or nano ink for shorthand. Essentially small custom semiconductors that are designed to recognize moonlight. ### Solution Nano-computer "ink" Cover a substrate with the nano ink. The nano ink would consist of small semiconductors that could be charged by sunlight. Designed to recognize moon light via spectral fingerprint. Allow resetting by some signal. Programming a message via light of particular frequency through an optical mask. The resulting device would something that would display writing upon exposure to moon light. Then you run into next problem of can the viewer actually read it... Since if the viewer then apply a lantern or flashlight that would deactivate the writing display. Moonlight isn't exactly great light to read by. With very low utility for the cost to design, it is unlikely to ever be made. ### Using more traditional ink: No. If you are wanting strictly a pigment/ink that was completely passive with no computing aspect, no magic aspect? That only reveals a message in moonlight and no other means? Then no. [Answer] Technically, probably yes. Let's use logic. First, let's ignore variations of moonlight, see if we can solve it for one specific, phase of the moon/spectrum of moonlight, at all. As you say, moonlight is reflected sunlight. So we can expect these differences: * Lower intensity (or missing entirely) at some frequencies due to reflection followed by atmosphere filtering of the modified reflection spectrum. * Some changes of frequency from absorbed/re emitted, etc, or Doppler effect (surely unnoticeable). * General lower intensity. Can any of those cause a message to be differently visible? * lower and missing intensity suggests an ink that is invisible under high intensity, or when frequencies in sunlight but not moonlight are present. For example, suppose the ink fluoresces.... *but not when exposed to some intensity/frequency in sunlight*, because say, the process under moonlight involves steps that preferentially happen a different way under sunlight spectra. Or its simply swamped and can't shine. Or changes colour but the reaction is inhibited by sun spectra/intensity. Or its covered by a 2nd layer that is transparent, but can't transmit that fluorescent frequency if exposed to bright light. * Doppler is probably undetectable, ignore. [Answer] You didn't specify what kind of time period your world is based in. My answer may be far fetched, but you can have ink that's actually [e-ink](https://en.wikipedia.org/wiki/E_Ink) that has some kind of logic or sensor that activates when moonlight is applied to it. Even if your setting is medieval, if you want "realistic" magic you can always go for the "magical artifacts that are actually pieces of really advanced tech from an old technological era" approach. ]
[Question] [ ## CAVEAT: NO TERRORIST SOLUTIONS (Obvious answer to any new tech that destroys stuff is "use it for extortion." That cheap trick won't get rewarded here) I have a device similar to what Douglas E. Richards' used in *Split Second* such that any object of less than 3 m3 size can be sent back **up to** 0.5 seconds in time. When it does, it exists *before* it leaves so for that split second there are two of them. It's a "Telecloner" which teleports something by sending it back in time, making a temporary clone form in the "destination" time in the past, until the "origin" time in the future. See the diagram: ![](https://i.stack.imgur.com/Oe8hj.png) 1. Mouse A exists. 2. T2 = 0.5 seconds before the mouse A is teleported. The mouse A appears in the teleported location 3. T1 = Mouse A vanishes from the teleportation area (It is not "destroyed" like a Star Trek transporter - it traveled back in time) 4. Mouse A exists in the teleported location alone, original mouse sent away. To visualize this better, Imagine a Star Trek transporter which “beams” you 20 meters away except you materialize 0.5 seconds before you dematerialize (yes, that means you are at your destination only slightly before you say “energize”) Earth's travel dictates that up to 3 times per day, anything up to the size of a microwave oven can be teleported between 5 and 50 feet away by sending it back in time up to 0.5 seconds. The machine must be stationary, but it is installed anywhere you want (a bank, office building, garage, back of a truck, port-O-potty, etc. and can teleport anything inside a safe, a drawer, room, garage, etc.) Hard science in the plot dictate that it can't to scale up. It operates by anchoring the small region in the scalar Higgs field, until the link between the machine and the space is broken. * **An Object in a defined spatial region** of 0.5 m$^3$ can be targeted from up to 3 feet away in open air. The region can be any ovoid region, or can be sculpted into a loose rectangle as well, limited by volume rather than linear dimension. Larger objects up to 3 m$^2$ can be telecloned only by using a special chamber, which can fit in a van. A person *could* be done with tremendous risk and has not been tried. * **You can’t choose the destination**: Where the item appears depends on the time and date. Why? The object does not actually move, but the earth and universe do, so it appears wherever that point in space was a split second ago. Simply put: It works by merely freezing the object in the timestream, while the earth (universe) continues to clock forward (and in every other dimension). The distance is determined by the movement of the earth, thus the operation limit. The list of things you have successfully telecloned is as follows: ![](https://i.stack.imgur.com/Ah6IV.png) Of this list, I am experimenting with which item may be the most profitable. Here's what they've done so far: 1. A wallet with a fake ID (and a driver license, a key, a credit card, and a contract in it) was transported into a government building. They entered the building as a contractor, then picked up the government ID once they passed security. 2. Yeast was multiplied several times to quickly make beer. 3. A mouse was transported into a sealed Schrodinger Cat box, with the cyanide trap. To see what would happen. The mouse was alive. 4. A signed check was put into the car from the house. It was cold outside. 5. A camera took a picture of a virtual Lotto machine as it stopped, a Web bot quickly typed in the winning number. The collection was closed 5 minutes before the drawing, but the robot got the right numbers. 6. A cheap parlor trick: A special unique coin was shown to some kids, put into the machine, and the kids found it in the freezer 20 seconds later. Never stopped talking about it. 7. A piece of the granite kitchen counter (a mineral) was transported into the yard, leaving a nearly perfect hole in the granite, and a nice big round granite coaster. 8. A jewelry box (with diamond and heirloom) was removed from a safe (with a sliver of steel with it. Oops.) 9. From the back wall of a pharmacy late one night, a random assortment of medications was telecloned out to the parking lot. With some shelving and an employee's RFID card. And other stuff. 10. A transmitting walkie-talkie radio was telecloned into the trunk of a stranger's car and recorded until the battery died. The stranger was a cop, and the walkie-talkie had fingerprints on it, and became evidence in a very strange wiretapping case. 11. A lit propane torch was telecloned into a large 50-gallon residential propane tank. It was one of the few experiments that went as planned. 12. A video camera showed a bullet hole in the wall next to a target in the hall. This was just before, outside the house and 20 feet East, a target was shot at in the yard. The bullet passed through a laser line to trigger the telecloner. Nothing hit the target in the yard. The bullet moved 20 feet West, and 200 ms earlier. **Concepts to consider:** * An exothermic chemical reaction sent backwards would double its heat output. * A radioactive source could be used to double its radiation for that time. * A breeding culture of cells/bacteria could rapidly populate. * Any bomb could be doubled, but the telecloner will be destroyed as well. * Any small object could be teleported through any material, for that short distance. Into a safe or vault, for example. # Q: From the list provided, what would would likely be the most profitable thing to send back? Please help by including your reasoning in the answer. * **Note:** Discussion about paradoxes should go to chat first. There will be dangers and faults in every answer: perfection is not sought, the question asks only for cold, hard, likely unethical, profit. --- **Concieved implications / Paradoxes:** There are horrific implications to this as essentially the "clone" which goes to the past can emerge inside a solid object if the timing is wrong, like Star Trek transporters. In this case, it would be quite horrible. You could literally watch yourself become transported into an object before you disappear. But weaponizing it can be a side arc for some entity who doesn't know how unpredictable it is. The weapon will fail horribly if they try—you're only 50 feet from the blast! This technology avoids the [Grandfather Paradox](https://en.wikipedia.org/wiki/Grandfather_paradox), it's still the current you that dies (not the past you). For that instant you are a clone. A [Causal Loop](https://en.wikipedia.org/wiki/Causal_loop) paradox is used because it is easy to shut down (remove power, no further iterations can occur). At the same time the Klinkhammer and Echeverria solution to the [Polchinski's paradox](https://en.wikipedia.org/wiki/Joseph_Polchinski#Polchinski%27s_paradox) can be the basis of the time pump: an object or volume of water repeatedly teleports backward to displace itself, accumulating momentum, thus creating flow. The challenge is you cannot control the teleportation direction. As such, the time pump piping has to be on a six axis gimbal so it can keep the water flowing in the right direction, and must operate intermittently. Hence, the time pump is very large and bulky. --- # FAQ: (For the purposes of forming an answer, time-travel problems need in-world mechanics explained. Per questions, here is the in-world answer): 1. What happens to existing matter at the destination? A: Sent back another 0.5 seconds; and that material is again sent back (1 second now), and *that* material is sent back 1.5s., and so on. Those alternate timelines never manifest in-world, you are the first harmonic. In the end, as far as you know it is just gone. 2. What is the precision of the destination? At 50 feet your object is placed in a region within 0.5 cm of the designed target. Shorter displacements reduce the error linearly. Thus a safely telecloned object sent 50 feet should expect to fall up to 1 cm. 3. Can the plot use the erasing feature to profit? A: No, it can not. That would be an answer for a disintegration weapon. The answer must employ the telecloning feature in the answer, as the title says. 4. How big is the smaller device? A: The smaller device can be a backpack-sized machine like Ghostbusters antimatter stream guns. But the device has to be stable and mounted to work, not on your back. It has to calibrate to the earth's movements very precisely before firing a successful nulling wave. Any vibrations will make the cloning fizzle and do nothing. 5. How big is the larger device? A: Like an office desk turned on its side. It can pack into a van but can't be launched from the van unless the vehicle is stabilized on jacks, and the telecloning booth is also immobilized. 6. Can I answer with the [Grandfather Paradox](https://www.space.com/grandfather-paradox.html)? A: The answer must use the telecloning effect to create a revenue, not any other side-effect of the device. An object and all of its information have come back from the future. While this creates other consequences, those consequences are not unique to this device/plot and don't answer this unique problem. [Answer] I think the microtrading is the correct solution. Having ability to move something back in time three times a day 0.5 seconds back (do I understand it correctly?) is just so constrictive, it is hard to come up with any an application at all. What I think might actually be more useful, is to just use it as a teleport in applications where the destination is impossibly hard to reach otherwise. (I am considering, that if you know the time and coordinates of departure point, you can determine the destination with arbitrarily high accuracy.) Need to put a bug into a crime boss mansion? You just need to park outside at the exact time and place. How about placing an item into a safe, that cannot be opened without signal being send (integrity protection). Or a sci-fy application. For example feeding tritium to nuclear fusion reactors, no need to include any valves ot entry, use your machine to get the gass inside. Nothing else comes to mind. [Answer] Stock prices. A chip capable of wireless communication gets filled with the current stock prices, is transported back in time, the data is read into an automated stock trading system and the stock trading system buys all stocks which will increase their price in the next couple milliseconds and then sell them the moment they do. In [modern, fully-automated high-frequency stock trading](https://www.investopedia.com/terms/h/high-frequency-trading.asp) every millisecond matters. Being able to look just 500ms into the future would allow you to make some pretty decent amount of money. How decent? Well, stock prices will rarely fluctuate by more than single cent values over such a short time. But do not underestimate the power of exponential growth. Even if each jump only allows you to make 0.1% profit, it will take you less than a year to double your capital. Start with $1000 and you are a millionaire in under 7 years, a billionaire in under 13 years and a trillionaire in under 20 years. [Answer] ## Bullet in flight Dumb fire bullets, missiles, and bombs are dangerous, but with a high speed camera, a computer, and this laser you can completely mitigate those threats. Whenever you see a bullet, missile or bomb, hit it with the laser. You may have to do this multiple times into the past, but eventually the target will move to a point where it won't hit its target. This is expensive, and would be a big investment, but secret service, billionaires, and military bases will pay a lot to protect their prime assets. If a missile or bomb is too big to teleport, don't worry, just teleport back as much as you can and the weapon will probably be disabled if you aimed right. The amount of money you get from the weapon therefore scales not based on what you send back, but by what you can protect, or what enemy ordinance you can destroy. Here are somethings you might protect, and their costs. * A US airbase: 800 million or more. * A F-15 Jet: 12-35 million in production costs. * An Aircraft carrier: at least 10 billion. * A Tomahawk missile: 2 million. * A Current US President: Money is no object. [Answer] ## The Higgs Boson Field The Higgs Boson field is the scalar field of energy that makes up the resting state of energy that all matter and energy seems to come from. While we think of the universe being mostly a vacuum, it is more like a calm ocean, filled with this deep source of energy that we can not directly detect because it is all in perfect equilibrium... but if you could move a small column of the Higgs Boson field over just a few millimeters you would create an energy gradient that could in theory be used as a power source that makes anti-matter or fusion reactions look like a child's play thing. The principles of thermodynamics say that energy moves from areas of high concentration to low concentration; so, simply moving over a column of the universe's resting energy would cause an unthinkably tall spike of potential energy that would want to radiate outward, next to what would be an unthinkably deep well of negative energy that would want to draw everything around it into it. If you were to harness this massive land-slide of energy it could become the basis of an unthinkably powerful energy source. The best part is that once the Higgs Boson Field falls back into equilibrium you can just do it over and over again as a sort of self fueling reactor. [![enter image description here](https://i.stack.imgur.com/HziEW.png)](https://i.stack.imgur.com/HziEW.png) Alternately, if you could get really good at controlling this reaction, you might even be able to use it as the basis for a [Alcubierre Drive](https://en.wikipedia.org/wiki/Alcubierre_drive) allowing you to travel faster than light since it would give you the massive positive and negative mass nodes you need to make one work. [Answer] **Cryptocurrency**. 500 ms is sufficient to copy the winning cryptographic solution to the current item in the block chain and replace it with your own. For example, you can mine fast transaction time cryptocurrencies 3 times a day (not that much profit on its own). **High cost information** in general. The basic idea is anything that requires global scale computation to reach a solution quickly, you can now win by 500 ms. [Answer] ## Mining Mining has led us through time ever since it was first discovered, So why not use the Telecloner in mining operations. Simply mount it facing downwards and run it for a few moments at a time, firing a concentrated beam as a sort of drill. The beam will travel down to the center of the earth, successfully teleporting minerals, dirt, and sometimes magma, which is a problem that can be solved as long as the area is clear of flammable materials and is shaped like a pot or spaghetti strainer. Thank you for your consideration [Answer] Just gonna try and throw an idea that isn't what you don't want. How about recording data of past events where there was previously no observer? Sending back a data recording device one second so it could record from past events that were missed by the interested party. This could have forensic applications. But what is 1 second to forensic scientist? Not much, but the possible application gives reason for further research to possibly extend that time. If you do decide to open a can of worms by allowing time travel for more than 1 second: Perhaps if you could send back an object partially and sacrificing the part that wasn't sent back as energy to send it back further, you could record for a longer period of time. But of course you still need the platform in order to go back, so that could be one of your restrictions, along with how much fuel you can provide the device to go back with. This could become an incentive for a luxurious commodity to develop. Something along the lines of purchasing a personal wayback machine so that you can revisit previous moments of your life which you didn't prepare to record ahead of time. At this point your time machine also becomes a message in a bottle. I can also imagine the surprise of people when they install the device, and a camera suddenly appears in it because their future self used it. At this point you cant really stop them interacting with it, they could just move it elsewhere until the time arises that they need to check its contents. Honestly after all that, I wouldn't allow traveling back more than 1 second, but those are good thought problems the characters could visit while trying to find a way to make it happen. But a more serious application would be something like finding an absolute coordinate system and calculating the velocity of the platform hosting this spacetime frozen particle. It doesn't seem like much but it has huge implications if it can be done. [Answer] # Electricity generation Use physics to your advantage! You say you can effectively double the energy of a bomb for example. This is wrong, as there's much more at play here. Not looking at the explosion we can already see a tremendous increase of energy. Putting a plastic ball inside another will put a lot of molecules close together. Double the molecules for the same space. They will start pushing on each other, releasing a lot of energy. In practice it would heat up and expand, possibly in shards. To make use of it we can teleport some water into other water. This will by my estimate already heat up enough to make it all superheated steam. This in turn can drive a turbine. Now include the solution to the Polchinski's paradox. Start by teleporting water into *itself* (or a volume that includes itself). It'll glance it into the right direction, causing it to smack into itself in the right direction to be teleported correctly 500ms later. Adding electricity generation can actually aid this and generate electricity. However, we might be able to manipulate this further. As I read it, the paradox doesn't need to stabalise immediately. It can teleport back in time, heat up to steam and repeat this cycle until the hot steam loses just as much energy to the surroundings as it generates. That means you basically created the same principle as a nuclear reactor, as you can use the excess heat to heat up water to steam and turn a turbine. Do note that this will probably take an insanely large building to cope with this. That is good for a ton of power. My estimation is that it can get far hotter than a neutron star if not destroy the universe. That means you have solved the energy shortage by 'simply' teleporting just shy of 3m³ of water 500 ms back in time. If this potential to power several worlds or destroy it isn't a way to generate money, I don't know what is. [Answer] **This is a [Frame Challenge](https://worldbuilding.meta.stackexchange.com/q/7097/40609)** *Nothing on your list would provide profit of any kind because one-half second isn't enough time for anything meaningful, useful, or practical to be acted upon — especially when you can't predict (to the micron!) where it'll arrive.* For example, at first glance I thought @Philipp's answer concerning stock prices was a good one. But then I started thinking about that one-half second window. You push the button and a chip with useful stock information is send backwards only one-half second. One-half second before you pushed the button your thumb was moving toward the button to push it. By the time you recover the chip and extract any meaningful information from it (no matter how it's configured into any other equipment), whatever value it had is long, long gone. *It's the ability to act on the event that's the problem.* And that means acting on it both before you push the button and after. Continuing to use @Philipp's answer as an example (I'm not knocking your answer, Philipp! I like it, I just don't think @VogonPoet's conditions allow it to be useful), let's assume that the recording device was installed in a machine that could detect profitable stock prices, write to the device, and trigger the event (you're thumb's no longer involved). Where would the chip go? You said that is could end up kinda anywhere (unless we can perfectly plot the motion of the Earth through the universe), meaning that there's a better-than-average chance you can't even recover the object before the trigger-time is reached. What's the point of sending, e.g., a photo back one-half second when it takes 30 seconds to recover it? You'd have been better off ignoring the time-shift. If the item can be guaranteed to appear in exactly the original space, then the chip would arrive into the slot that one-half second before it occupied. Which I'm willing to guess would cause a brief moment of nuclear fission. Unless you can dematerialize that chip *in the exact spot in another computer that can react to the presence of the chip in less than one-half second,* I can't see any value at all. *And that's ignoring the fact that (a) insertable objects are inserted against springs, which wouldn't happen in this case... fission... and (b) that the drivers the software invoked to read the suddenly-appearing chip could identify the device, extract the data, and use the data meaningfully in just one-half second. You're obviously not using a USB flash drive.* **Conclusion** None of the items on your list have any profitable value because you have a condition that's so short that either you can't adequately act to prepare the item before the time-shift, or you can't act in a practical way on the device after the time-shift, or both. Information is the only thing that might be of value during so short a time, but your inability to recover the information and put it to use in just one-half second guarantees there will be no profit. **So, let's challenge the Frame again and suggest extortion** Extortion is, off the top of my head, the only meaningful solution. You need to get the compromising-information-containing-device *away from the scene of the compromising event* as fast as humanly possible. You're kinda hoping it's closer to 50 feet away than it is just 5 feet, but at least there's a practical use, because it doesn't matter when the information is put to use. The only profitable event is one where you don't need to act on the result of the time-shift before the moment of the time-shift is "again" encountered. Meaning your time-shift isn't actually valuable at all (because of that one-half second window), you're just using it as a less-than-perfect spatial transporter. *Honestly, what could possibly be valuable if it appeared only one-half second earlier and not exactly (and I mean **exactly**) where you need it?* [Answer] # Oracle Stacks of small objects with 64 different ASCII codes (A-Z, 0-9, punctuation) are prepared near the cloner. It can send back any one of these. The reemergence site is monitored by camera and OCR. Whatever letter appears is recorded, and *that letter* is then sent back. Note that you never roll any dice. The letter that appears is one that was deliberately selected. The letter was selected by the fixed procedure of matching whatever letter appeared. There is a paradox. It is up to the *universe* to solve that paradox. The content of how it solves the paradox is an expression of some larger force from beyond the universe. It is not possible to predict what that force will tell you, but it ought to lead to interesting results. * *Technical note: you've just invented consciousness.* # Telecloner You're limited to sending objects only 0.5 seconds because you only have one telecloner. Wait a minute: *you only have one...* um, you see where I'm going with this? You teleclone the telecloner back 0.5 seconds in time ... every 0.4 seconds. So you have a *string* of these things in some convenient environment (space). Clone a message in the last telecloner that appeared, and it appears right next to the one previous, where it is ready to be cloned an instant after *that* one appeared, and so on. TLDR? If you clone the cloner first, the 0.5 second limit goes bye-bye and you can start sending a more general set of information. ]
[Question] [ I'd like to have a forest with trees that are "normal" except that as they grow a big, hollow bulge forms in their trunks about halfway up, giving them a shape something like [this](https://i.stack.imgur.com/Q06uV.jpg), with a relatively straight trunk above and below the bulge. The bulge would be almost entirely enclosed, though there could be a few small holes or one larger one. The trees would live and function normally. For size, I'd like it to be possible for bulges to have a horizontal diameter of at least 30 feet on the inside. They would be taller than they are wide, as shown in the example images. On the outside, I'm imagining the bulge to be something like 3x the diameter of the trunk above and below the bulge. Functionally I think this could work, as I believe the inner wood (heartwood) of a large tree is usually dead anyway, sometimes even rotting away, and it is only the outermost layers that are still alive. I'm mostly asking what would cause a tree to grow such a bulge. E.g. maybe there's a tendency for a gas or liquid (possibly some kind of waste?) to build up inside as the tree grows that eventually creates a hole to the outside and drains? But why? [Answer] Toborochi Tree, Bolivia. The silk floss tree (Ceiba speciosa, formerly Chorisia speciosa), is a species of deciduous tree native to the tropical and subtropical forests of South America. It belongs to the same family as the baobab and the kapok. The swelling in the trunk is from water storage [![enter image description here](https://i.stack.imgur.com/pwkvy.png)](https://i.stack.imgur.com/pwkvy.png) <https://www.pinterest.co.uk/pin/332914597434451584/?lp=true> Although the bulge is caused by water storage I don't think the bole is actually hollow. Or is it ... [![enter image description here](https://i.stack.imgur.com/5qN4g.png)](https://i.stack.imgur.com/5qN4g.png) [Answer] **Giant burls.** [![burl!](https://i.stack.imgur.com/NL82Q.jpg)](https://i.stack.imgur.com/NL82Q.jpg) <http://www.supertopo.com/climbing/thread.php?topic_id=781108&tn=800> In hardwoods, burls are knobby warty overgrowths caused by response to some sort of damage - often fungal infection. The woody growth walls off the pathogen and protects the rest of the tree. Burls are a normal thing for redwoods. Most big ones will have some burls. They are also knobby growths but serve a different purpose for these trees. <https://www.nps.gov/redw/planyourvisit/upload/Redwood_Burl_Final.pdf> > > Burl is the knobby growth most commonly seen at base of some coast > redwoods, though it can also be found high in the canopy as well. Burl > is a woody material full of unsprouted bud tissue. It serves as a > storage compartment for the genetic code of the parent tree. If the > redwood falls or is damaged, the burl may sprout another redwood tree > known as a clone. > > > The burl is a fallback defense in case the tree falls down. It can sprout back from one or more of its burls. So too your trees. Once they get to a certain height and are at risk of being toppled, each develops a big burl. If the tree falls the burl kicks in growing. A burl is bigger than any seed around and can rapidly reclaim the hard-earned space in the forest before that space is filled in by upstart seedlings. --- **Giant galls.** [![gouty oak gall](https://i.stack.imgur.com/bvA6h.jpg)](https://i.stack.imgur.com/bvA6h.jpg) Galls are similar to burls but smaller, and caused by insect pathogens. The insects hijack the tree growth mechanism to make themselves an armored chamber. <https://tfsweb.tamu.edu/OakGallInsects/> > > Growth deformities known as galls commonly occur on oak trees in > Texas. Most oak trees are attacked by a group of small insects called > gall makers. These insects can cause deformities, called galls, in the > leaves, twigs, bark, buds, flowers, nuts, or roots of the tree. > Because of the unusual size and shape of the horned oak gall and the > gouty oak gall, they attract the attention of landowners and > homeowners who are concerned about what causes the galls and what harm > or damage they will do to oak trees. > > > Your trees have giant galls. Once they get to a certain size, something moves in and hijacks the growth of the tree, forcing it to create a gall-like chamber. The growing thing feeds off of the tree sap. Maybe these things stay in their tree, releasing spores or seeds or motile forms which go off to find new trees. Maybe these things break out once they reach maturity, leaving a gall with a big hole and a space inside. Some real galls have holes where wasps break in to lay an egg on the caterpillar inside. Your giant galls might have holes for the same reason - something wants to get at the creature living inside. [Answer] If you have a tree that lives in a place where rain is very rare, but torrential when it happens, this kind of adaptation could be about water storage. Many cacti actually have similar shapes to this for this reason; so, it's not a huge stretch. The problem for these trees is that animals know there is water in those bulges; so, they will try to burrow in for a drink which would make the holes. If the holes are small and high enough, then then tree could survive with most of the water staying in the hole, but many such trees will be dead empty husks broken open by larger animals over time. That said, the "half-way" up aspect would be a good way to keep water storage away from most animals in lue of thorns like cacti need as a deterrent. This way the trees have a "fighting chance" while remaining more or less normal. [Answer] The hollow bulge is home to a symbiotic organism that protects the tree from herbivores in exchange for shelter (and possibly food as well). One real-world example of this sort of relationship exists between the [acacia ant](https://en.wikipedia.org/wiki/Pseudomyrmex_ferruginea) and the [bullhorn acacia](https://en.wikipedia.org/wiki/Vachellia_cornigera). [Answer] So you imagine the tree trunk to be about 10 feet wide above and below the bulge and the bulge about 30 feet in diameter. It seem to me that most trees are very heavy above any points in their heights where their trunks are 10 feet in diameter. That is important because the upper trunks in your trees would not be supported by wood directly underneath but instead would be supported from the wall of the bulge on the side. So the possibility of that bulge not breaking would depend on the strength of the living hollow wood of the bulge to support a great weight in a sideways direction. On the other hand I have seen a little grove of very tall and incredibly slender black walnut trees, possibly the tallest in the world, with branches sticking out unsupported at various angles for tens of feet, and one tree in the grove has a sort of a S shape with many tens of feet of height supported only from the side. So the possibility of those hollow bulges depends on the strength of the living wood of those tress. [Answer] They were bred that way. Depending on the plot of your story there could by many variations * The indigenous intelligent beings did it * An unintelligent being accidentally did it, similar to what was mentioned about ants and galls in other posts * Intelligent beings that no longer exist did it * Variations and combinations of these factors, maybe it was unintelligent beings who started it, then intelligent beings furthered it and became extinct, now indigenous intelligent beings have perfected it. ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). Closed 5 years ago. [Improve this question](/posts/124917/edit) In a far away future, when/where technology has erased scarcity, competition and poverty, what purpose does civilisation still have? Suppose a civilisation reaches a level at which it can harvest solar energy to fuel energy matter constructors and use these devices to create any object in any quantity forever, have automated robot workforce to fill in any remaining menial tasks available (run by limited virtual intelligence so as to avoid a matrix or terminator apocalypse), and have the ability to heal any wound or illness through nanotechnology or cloning. A true, honest-to-God utopia. [![a true, honest to god utopia.](https://i.stack.imgur.com/GtYks.jpg)](https://i.stack.imgur.com/GtYks.jpg) Does civilisation hold any meaning any more? Do people have any purpose left? Is society as a whole left with any meaning? (Assuming for the purpose of this query that we don't turn into some form of religious zealots.) Also, besides it being a better alternative to a dystopian future, do we actually want to evolve into a utopia? [Answer] **It's time for your civilization to be asking The Last Question.** Because... > > If a civilisation reaches a level at which it can **harvest solar energy** > to fuel energy matter constructors and use these devices to create any > object in any quantity **forever**, ... > > > It's not "forever". Our sun, and indeed the universe itself, is like a spring-powered clock which is slowly winding down. The laws of thermodynamics, as we currently understand them, preclude the possibility of a truly perpetual, life-sustaining physical existence. So, the search for a solution/workaround to the problem of entropy becomes the main project of civilization, and supporting projects would include finding ways to prolong our long-term existence while we try to solve that problem. This answer was brought to you by Isaav Asimov's short story, The Last Question. <https://en.wikipedia.org/wiki/The_Last_Question> [Answer] **The Greek Ideal** Your society haven't eliminated all work, only the manual work. You have robots and AI's doing the most mudanes tasks, allowing the humans to focus on the arts, the science, philosophy, and basically anything they desire. A regular citizen will be a true renaissance man, studied in several different art and scientific school, they will create the most beautiful sculptures and write melodic poems while machines keep the sewers clean and farm for food. Without having to worry about budget limits and constant inquiry from a board of directors, people will be able to pursue scientific knowledge with ease, free to explore the more arcane areas of the sciences without having to worry about profits. Sports will always be popular, with the possibility of cloning even death sports becomes a possibility. For those in search of a bigger challenge, they could even clone strange and mutated animals for sport hunting. Finally, there will be the exploration of space, ships being sent towards distant systems, and even if no alien life is found out there, then it just means that it's time for these humans to start themselves seeding the universe with life. [Answer] An interesting take on this question (the substance of it, if not the exact technological detail) can be seen in EM Forster's [The Machine Stops](https://en.wikipedia.org/wiki/The_Machine_Stops). Within three generations, humanity would no longer have the capacity to manage even trivial failures in the overall system. If this utopia was achieved, it would likely crash as soon as the automated maintenance systems encountered a situation for which they were not designed. A problem-solving autonomous AI might get around that limit, but you specified that your setup doesn't have that due to "Terminator Risk". Edited to add: It strikes me that I didn't describe the mechanism by which humanity would lose the ability to maintain the system over a three-generation span. Essentially, think of your utopia as an office with custom software that runs everything. Now eliminate everyone who knows how that software was written, and even everyone who knows *what software is*. Now wait 100 years. Unless you intend to keep the founding generation alive forever, and enslave them to all subsequent generations. And even then...good luck keeping up the level of expertise you'll need after the first 1000 years of total idleness on the part of even that founding generation. I can't remember everything about the code I wrote a year ago. [Answer] ## A perfect Utopia is impossible At least with humans (as they are). There will always be greed, envy, hate. A certain percentage of people are born psychopaths. Whilst they benefit a population in crisis, they are a burden in peaceful times. It is a natural human drive to strive for more. To distinguish themselves from others through status or status symbols. You will **never** have a perfect human society. [Answer] As others have mentioned, you can't erase scarcity and competition. What you're proposing is displacing scarcity from resource and wealth scarcity to some other aspect, like ability. We can both 3D-print any sculpture we imagine, but I'm better than you at imagining sculptures. This creates a competition, where I want to stay on top and you want to become better than me. For this reason we have local sports tournaments played by non-professionals who don't aspire to become professionals players. This could easily (with the resources you propose) be escalated to a global level, where many, many disciplines are recognized and everyone is ranked in the disciplines they pursue. Something like the olympic games but with a couple of orders of magnitude more disciplines (including all arts and all videogames) and almost the whole population participating. Those who don't participate are too busy inventing new disciplines! Also, while you propose eliminating scarcity of resources, there is still the matter of scarcity of energy (our sun produces a limited amount of energy, which presumably could be converted to a limited amount of whatever-you-want), and the scarcity of available space (unless you can 3D-print a real TARDIS, bigger on the inside). [Answer] You cannot erase scarcity and competition. People will always want more. Better food, prettier clothes, cooler gadgets, bigger house, etc. B/c for humans, "enough" means "more than average". If you look at quality of life that people had 100 years ago, you can easily get achieve and exceed it by living on welfare (at least in Europe). Yet most people want more, and are willing to work and compete for it. If enough people are convinced that they cannot improve their lives, then you will indeed have end of progress and stagnation. I believe this was the case throughout most of ancient history and middle ages. Some would argue that this mindset affects the able-bodied people who stay on welfare for years and years. [Answer] # It depends on your philosophical axioms. If your concept of "purpose" is set up in a way that satisfaction of sentient beings is the ultimate purpose then the answer is **yes**, the Utopia is definitely worth it. The ultimately evolved civilization serves its individuals by providing them with pain-free, stress-free life, while simultaneously quenching intellectual thirst. Everybody can relax and enjoy infinite possibilities without fear of any harm falling upon them. If, on the other hand, every sentient individual has to fulfill a purpose (but towards what or who?), then **maybe not**. For some strange reasons I can't quite fathom, this philosophical opinion seems to be *more popular* among the general population of people who think about the concept of purpose. ]
[Question] [ **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. Back home, Earth had gone through an impact-coalesce cycle only once. Since then, its core has been 84% iron, 6% nickel and the rest being labeled by *The Encyclopedia of Earth: A Complete Visual Guide* as "Other". In this alternate scenario, Earth had gone through multiple impact-coalesce cycles over a course of 600 million years. As a result, iron still makes up 84% of the core, but the remaining 16% has the greatest concentrations of the planet's heavy metals, all of them. [(List of heavy metals in this link.)](https://www.thoughtco.com/definition-of-heavy-metal-605190) How would this difference affect Earth's overall chemistry? [Answer] > > How would this difference affect Earth's overall chemistry? > > > Not much (but see below). Here's why: **Let's start with some background** The core–mantle differentiation event was the melting event which caused separation of the rocky mantle and the metallic core. It separated earth into two phases (in the chemical sense): 1. Metal, which is dense so it sank to the bottom. This is the core. 2. Rock, which is less dense than metal, so it remained at the top. This is the mantle, which then subsequently differentiated into crust and mantle, but that's not important for now. What are the "metal" and "rock" made of? The metal is mostly metallic iron and nickel, it is possible there are other lighter elements in there, but they are probably negligible and do not exert control on the chemistry. The rock are silicates: Basically magnesium, calcium, aluminium, iron, bonded to chains of silicon oxide. You can see why "rock" is less dense than "metal": it has lots of silicon and oxygen which are very light elements. Notice something interesting: the "rock" also has iron. Why is this iron in the "rock" and not in the "metal"? The answer is oxygen. Earth has a bulk chemical composition - it has a fixed amount of elements: iron, magnesium, silicon, etc., and most importantly oxygen. Oxygen is, well, an oxidiser. It will want to bond to other elements. When elements are bonded to oxygen, they start behaving like "rock" and not like "metal". However, certain elements will want to bond to oxygen more, quicker, easier, than other elements. Out of the major elements that exist in the Earth, Si, Mg, Al, and Ca really love oxygen. Fe and Ni less so, but they will bond to it if it's around. Turns out that the amount of oxygen in the Earth was enough to bond all Si, Mg, Al, and Ca and make them into "rock". A little was leftover to bond to some Fe and make it into "rock" as well. The metallic Fe (and Ni) is basically the leftover of this oxidation. Because they had no oxygen to bond with, they remained as "metal", thus forming the core. **Good, now what does it mean for the minor and trace elements?** Note that I'm not using the term "heavy metals" here, because it's a loosely defined term. For example, the list in your link includes titanium, whereas most people in the alloy industry will consider it very light. Instead, I'm using the term "minor and trace" to refer to anything that's not Ca, Si, Mg, Fe, O, Al, etc. These minor and trace elements are controlled by the presence of "metal" and "rock". They will partition to either the "metal" (i.e. the core) or the "rock" (i.e. the mantle and ultimately the crust), not according to how heavy they are, or their atomic number, or density. They will do it according to their chemical affinity to a metallic phase or an oxide-silicate phase. This is known as Goldschmidt's classification - the cornerstone of modern geochemistry. It categorises elements into several groups: 1. Lithophile (rock-loving elements) 2. Siderophile (iron-loving elements) 3. Chalcophile (sulfur-loving elements, although "chalco" means copper) 4. Atmosphile (mostly gas, not relevant now). Here is how it looks like: [![enter image description here](https://i.stack.imgur.com/Dcqrc.png)](https://i.stack.imgur.com/Dcqrc.png) [From the relevant Wikipedia page.](https://en.wikipedia.org/wiki/Goldschmidt_classification) So even though thorium and uranium, for example, are very heavy, they will partition to the mantle and not much is in the core. Cobalt is relatively light, but it will go to the dense core. This is one of the reasons why there is so little gold and platinum in Earth's crust - it's all locked up in the core, far away from our reach. They are in the core not because they are dense and sink. There is too little gold and platinum for them to significantly affect the density of the metallic "blob" we call the core. They are in the core because they really like being in molten iron-rich metal (which happens to sink because it is dense). Likewise, thorium really loves being around silicon and oxygen, and the oxygen is in the mantle "rock". This is why it's not in the core despite it being one of the most heavy/dense metals in existence. Now here's the thing - the Earth is already differentiated. Melting the entire thing again will not actually do anything. The gold is already in the core, and the thorium is already in the mantle. Here's an example: take some ice and solid vegetable oil, crush them to small flakes and mix together. Now put them in the sun for a bit. The now-liquid ice and oil will separate, oil on top of water. If you add in a bit of oil soluble and water soluble (e.g. salt) materials, they will partition to their respective phases (i.e. water or oil). Now put it in the freezer again. And take it out again. Not much will change. This is how the Earth will be. **But there's one very important exception!!** We actually have more precious metals than we should. The precious metals (Pt, Au, Pd, etc) are the most siderophile elements known. They should all be in the core. But yet, we have some. Not much, but some. You wedding ring is made out of gold. You have platinum or palladium in your car's catalytic converters. Where is that coming from? One theory is the **late veneer theory**: After the Earth differentiated to core and mantle, and while the mantle was still molten, impacts of asteroids delivered additional material to the Earth, in a pre-differentiation composition. Thus, even though all the initial precious metals were locked in the core, we got more stuff. And because all the metal is now thousands of kilometres deep, it cannot access the new precious metals that were acquired. Melting everything all over again might result in some of the late veneer material, the precious metals, to be lost to the core again. But only if it can get into contact, or there are convective forces in the mantle to mix it, or it's happening for long enough for the elements to diffuse it. But since you're suggesting impact events, I don't see a reason why this can't happen. So to answer your question again: > > How would this difference affect Earth's overall chemistry? > > > We will lose some amount or all of our precious metals. For further reading on some of the topics discussed in this answer: Christy (2018) Quantifying lithophilicity, chalcophilicity and siderophilicity <https://doi.org/10.1127/ejm/2017/0029-2674> Righter (2013) Metal-silicate partitioning of siderophile elements and core formation in the early earth <https://doi.org/10.1146/annurev.earth.31.100901.145451> Brenan et al (2016) Experimental results on fractionation of the highly siderophile elements (HSE) at variable pressures and temperatures during planetary and magmatic differentiation <https://doi.org/10.2138/rmg.2016.81.1> ]
[Question] [ I have dinosaurs, I have an asteroid I want to save the dinosaurs from the asteroid, but I'm not allowed to use the giant laser again, after that incident in Alderaan. So I have only one chance left... ## The [Giant Housemaid mech](https://youtu.be/EWQAvMUUJr4?t=33). I want to make things sure, so **I need a vacuum cleaner that is big and strong enough to suck out half of the current Earth's atmosphere under a week.** I also want to make sure that the dinosaurs don't get killed so, it's important to know, **What effects would this vacuum cleaner have in the planet's weather?** (this implies, that the air gets filtered then immediately returned to the atmosphere. There were other factors to the extinction, but let's focus on the more pressing matters at hand. [Answer] As many have pointed out so far, Mega Maid has some physical limitations. It's almost like it's just a plot point in a movie or something! But that doesn't mean there's not options. What you are looking to do is similar to what we have to do in real life in clean rooms. In fact, it's something [similar](https://www.terrauniversal.com/cleanrooms/iso-classification-cleanroom-standards.php) to what we do with normal air conditioners as well: > > A critical factor in cleanroom design is controlling air-change per hour (ACH), also known as the air-change rate, or ACR. This refers to the number of times each hour that filtered outside air replaces the existing volume in a building or chamber. In a normal home, an air-conditioner changes room air 0.5 to 2 times per hour. In a cleanroom, depending on classification and usage, air change occurs anywhere from 10 to more than 600 times an hour. > > > 10 to 600 air changes in an hour is a lot! That's way more than your half-an-atmosphere-in-a-week criteria, though admittedly for a *much much much* smaller volume of air. But they also have an interesting criteria called "laminar flow." Basically, the air circulators in a clean room aren't allowed to create any turbulence. If they created turbulence, the eddies could suspend particles for an unknown amount of time, but if the flow is smooth, the lifespan of a particle in the air is well defined, and quite short. You're not going to need laminar flow to do your job, but your calls to not change the weather are very reminiscent of that requirement. Weather typically goes hand in hand with chaotic turbulent flow, so if you minimize the amount of turbulence you create, you're going to minimize your weather issues. You can take lessons from the clean rooms and apply them to save your dinosaurs! One of the big keys to how clean rooms do their job is distributed air handling. They don't have just one air intake on one side of the room. The area is peppered with holes for the air handlers to pull air out of the room. The ceilings also are designed to maximally distribute the air across many openings so that there is an even flow of air from ceiling to floor, pulling all the dust out they can. You should do the same. Now I don't know what your budget is, but given that you've gone back in time, I'm assuming you can predict the result of enough [football games](https://www.youtube.com/watch?v=zorz3SXqjv0) to cover some pretty outrageous bills. This should be enough to build enough hardware to distribute your megamaid across the entire earth. Now don't get me wrong, you're going to do some environmental damage. Let's say we want out air handler to take up 1% of the total surface area of the earth. That's going to involve cutting down a lot of forests, but it's distributed so you should be able to do so without causing the extinction of too many species. Install the the "return vents" near the ground this way, and we'll put the outlets way up high. The stratosphere should do the trick. Now our air intake area is pretty massive. It's now 5,100,000 square kilometers! As Chris M. pointed out, the atmosphere is 4,200,000,000 cubic kilometers, so to process that in 7 days you need to process about 7000km^3/s. Now seven thousand cubic kilometers of air is a *lot* of air to move in a second, but we get to move it with a substantial distributed air intake, so the air flow rate only has to be 1.3 m/s! Now that's a noticeable 3mph breeze, straight down, so it will definitely have some effect on the weather, but a manageable one. If you can expand your budget by predicting a few more UFC tournaments, and can take up 10% of the planet's surface area, you can bring it down to 0.3mph, which would be unnoticeable. [Answer] I'm not sure if it just my vacuum cleaner on my rugs, or if it is an aspect of all vacuum cleaning everywhere, but the static electricity in the air seems to rise whenever I clean the rugs. Scale that up to planetary size and your maid mech might just be trading a nuclear winter for the mother of all lightning storms. Do you prefer your extinct dinosaurs frozen or fried? [Answer] **One extinction for another** The [atmosphere](https://en.wikipedia.org/wiki/Atmosphere_of_Earth) has a mass of $5.5\times10^{18} kg$ processing half of it ($~2.75\times10^{18}kg$) in a week means processing $4.5\times10^{12}kg$ of atmosphere a second. That's four and a half trillion kilograms per second. Now the fastest you can get air to move using a vacuum is the speed of sound, so about $340 m/s$. The majority of the mass of the atmosphere is in the troposphere and one cubic meter of air has a mass of about one kilogram. Therefore we can assume a volumetric flow rate of $4.5\times10^{12}m^3/s$ of the atmosphere. With those parameters, the opening of your vacuum would have to have an area of $1.3\times10^{10} m^2$. We are limiting our work to the troposphere so the height is ~10000 meters making the aperture 1.3 million meters long or 1300 kilometers. Moving air this fast creates pressure drops that will be in their own right fatal over a large area. This pressure drop will also create enormous super storms and lightning and likely kick up megatons of dust. And that's just the info flowing of the air. The outflow is worse, again dust storms, lightning, supersonic winds. But now with all that hot air you will produce the mother of all storms: [Supercells](https://en.wikipedia.org/wiki/Supercell) and [Hypercanes](https://en.wikipedia.org/wiki/Hypercane) if too close to water. Driven by super heating these storms will push water vapor into the upper atmosphere and destroy the ozone layer. **You just kill them faster** [Answer] Earth's atmosphere is something like 4.2B cubic kilometers. [Source](http://www.sciencephoto.com/media/159214/view) To remove half of it in a week, you'd need a vacuum cleaner that can move: 2.1 x 10^9 km^3 / 7 days ***conversion math*** Approximately 7.4 x 10^24 cfm. Ignoring the fact that this would take yottawatts of power to do, you're going to at minimum create absolutely ridiculous windstorms drawing that much air that quickly through a filter. Weather patterns will be interrupted, massive tidal waves will form, and you'll probably end up sucking all the flying dinos into the filter. Also, you're going to heat the air quite a bit during filtration, so you might accelerate the natural warming and cooling of the Earth and cause an ice age when you're done. And probably cause extreme weather beyond anything the planet has seen up to this point as the weather patterns try to resume. Maybe...maybe don't do that. Or do it anyway, but realize you're probably just killing all the dinosaurs faster. [Answer] Let it rain. No really. Rain clears up the sky [nicely](http://news.mit.edu/2015/rain-drops-attract-aerosols-clean-air-0828). But it will need to be long. I don't think it needs to be heavy. So it doesn't have to be a storm. Your beloved dino's will be wet for some time, and some will die. But those pesky mammals and humans will not get their change this time. Shower Bot it is. It will lead to other problems, like that rain is toxic now. River systems will change with the amount of new material. And I don't want to know what happens to reefs. And you might end up with a flooding event. Bugger... [Answer] The volume of the atmosphere at sea level 4,200,000,000 cubic kilometers. Cleaning half of it in 1 week means you have to clean 300,000,000 cubic kilometers a day, in other words 3472 cubic kilometers/second. To have this with a wind of 10 m/s (0,01 km/s), you need an opening of 374200 square kilometers. Limiting the height of the suction hose to 10 km, you need to have it 37420 km long, which is roughly the Earth circonference (40075 km). I don't venture forth in calculation, but I am pretty sure this will disrupt atmospheric circulation as the dust is already doing. [Answer] When Designing your Mega Maid, get a hold of the voltron and pwer rangers design teams to creat...**Mini Maids**. These things will still be enormous, but instead of one giant mega-maid, you add flexibility to your response. Arrange them close, but not too close, to the point of impact and spread them out from there. Say only a few thousand on the point opposite the point of impact, but they get denser and denser the closer they get to where the projected impact will be. Each Mini Maid will be equipped with a super air chiller to bring the air temp down to normal as it exits the exhaust. Also, efforts to reduce electro-static charge will be made. Finally, condensation that may result from chilling will go through a sprinkler head to create "rain" and help further filter the air. Finally, once all of the dust has been collected, route all Mini Maids to a remote part of the pacific ocean to empty the collection containers. We will call this collection area...Australia. Any nasty stuff picked up can be taken to Washington DC. Creature remains should be distributed randomly to make future scientists think that the planet had one super continent. We can laugh at them in generations to come. The point of a clean room, as has been stated, is to achieve many many air changes. One large filtration unit will create devastating effects, but several hundred thousand will probably lessen these to a great degree and be more efficient to boot. Lets just hope that not too many dinosaurs get sucked up in the process. Those carpet brushes can do a number on small, squeaky things. ]
[Question] [ In this world everyone has superhuman abilities and multiple abilities are a thing although it's rare to see more than 2. Some abilities are also more common than others like creating fire or ice is more common than summoning spirits. Knowing that, our main character has a rather unique ability. He can manipulate vectors to a certain extent. When he comes into contact with an object he can steal the object's vectors and store them, and he can also visualize all vectors associated with that object and steal those as well. He can then use this stored energy to apply vectors on objects in any direction and any velocity (limited by the energy he has stored). ***Example*** He can stand in front of a moving train and by touching it he can immediately stop the train and every person and object inside it (negating inertia) and storing all the energy from the vectors (he would also have to kill the engine but you get the point) There's also pretty interesting things he can do with his ability like negating a bit of gravity and storing energy passively while making him lighter, or negating more so he can jump high. Now my problem with this ability is that I can't find a lot of weaknesses apart from isolating him in vacuum so the question is, what other weaknesses would this ability have? ***Note*** This ability only steals vectors related to movement. If you want to, you can think of it as stealing kinetic energy. It's just that it wouldn't go well with his visualization. [Answer] ### Gas him, drown him, electrocute him, set him on fire. You're thinking in terms of applied violence which is his strength. Use things that aren't his strengths against him. * Wire his doorknob to the mains * Drop a toaster in the bath * Barricade his front door, pour petrol through the letterbox and set it on fire * Sabotage his boiler so he dies of carbon monoxide poisoning in the night * Tie his shoelaces together * Mock him until he runs away crying * Put laxatives in his tea If you confront him in the street to have a fist fight, you're not going to win, but he's apparently otherwise still an ordinary mortal. > > Build a man a fire, and he'll be warm for a day. Set a man on fire, and he'll be warm for the rest of his life. - Jingo, Terry Pratchett > > > [Answer] A few potential weaknesses that come to mind: **Battery capacity** He has a finite capacity to store this kinetic energy. What happens if he has to stop something that overloads that capacity? Does it injure him, or explode outward in random ways or other sorts of potentially bad backlash? What if the battery is empty? Does he feel that as a something like hypoglycemia, where he has trouble focusing or acting until he's absorbed *some* energy? **Heat 1.0** In the real world, temperature is a measure of kinetic energy at an atomic level, IIRC from high school science classes. Therefore, the more kinetic energy your mage takes from an object, *the colder* that object becomes. *Flash-freezing a train full of people* will not win friends and influence people. Therefore, he'd have to be careful how he used his powers around living things. Perhaps this issue only triggers if the delta between starting vector and final vector is above some arbitrary amount, so stopping a slow-moving train cools the interior a bit and maybe fogs the glass, but stopping a bullet train at full speed is more like a quick dip in liquid CO2 or worse, liquid N2. The reverse would be true for *adding* vector energy: more energy means more heat. **Heat 2.0** Or maybe all that temperature delta gets transferred to the mage instead of the object. So if he takes on too much motion, he gets a fever. So there's the limit to his battery: he *could* stop a bullet train at full speed, but that much energy would literally cook his brain. Releasing the energy would also cool him off, so speeding that bullet train from dead stop to full speed might cause deadly hypothermia. **Concentration** You say he's aware of all the vectors. How much concentration does that take? Can he easily concentrate on slowing a stroller rolling down the hill? Is it harder to mentally juggle all the vectors involved in stopping that train and all the people and cargo on board? Maybe that's his weakness at larger scales: he simply can't "do the math" fast enough for something that big. Or maybe he tries to stop that train, but fails to stop *that one person asleep in the back* who is now going to ram into a completely immovable seat with a great deal of force. Or do more complex sets of vectors take longer to manipulate safely? Maybe he has to start stopping the train with the last car, then work his way forward so each car helps brake the others forward of it, otherwise the whole train will pancake into a messy pile of scrap iron and people-goo? **Micro Control** Does he have highly refined control of this power? If not, he might accidentally steal biological vectors. This could induce blood clots or interrupt their breathing, or halt the various enzymes and other molecules moving around inside a living being that, well, *are* life. Or halt the air flowing into a person... **Macro control** if he forgets in a moment of panic, he could accidentally (or perhaps not so accidentally) negate the vectors imparted at a macro level. Suddenly your victim is not moving. *But the Earth still is.* At the equator, that's over 1,000 mph. Imagine Bob standing on the street you stop him, and quite literally the world smacks into him at that speed -- a building, a parked car, a tree... at these speeds, it doesn't much matter). Or worse, the earth orbits the sun at about 67,000 mph. So now Bob is either ripped off the earth in a blur of motion, or pancaked into a micro-thin puddle as the earth tears into or away from Bob. Or at an even worse scale, the solar system moves through the galaxy at about 515,000 mph. (speeds from [space.com](http://www.space.com/33527-how-fast-is-earth-moving.html)) Taking away THOSE vectors would be... *bad.* [Answer] To Aru Majutsu no Index is an anime series that has a character who has that ability, nicknamed [Accelerator](http://toarumajutsunoindex.wikia.com/wiki/Accelerator). Conveniently, thanks to some training, he also had a computer like brain ability so he could passively deflect even sniper rifle bullets to the back, and once even reprogrammed a computer virus. He however had 3 weaknesses (4 if you count the main protagonists power to negate any and all supernatural phenomenon) They are revealed throughout the series and/or in the Light novel. 1) While he could reflect punches when they hit him, he was weak to the One inch punch style of attack after it hit him. The fist gently landing on his body meant it would not deflect, but would otherwise be a soft touch. Then the attacker would punch after contact had been made, resulting in a lot of force. He was so skilled he could punch, pull the punch, softly touch Accelerator, and then resume the punch, in what appeared like a regular punch, and Accelerator would take the hit like a regular punch. 2) He was unable to manipulate vectors of material and matter that did not work like regular matter. Another person with the superpower to control dark matter could use it to conventionally attack, and its naturally abnormal physics made its vectors nearly impossible to manipulate. He may have been able to figure it out eventually, but I do not know that. Regardless, since the material did not work like he would have expected it to, he was unable to calculate is vectors and manipulate them. 3) The power was only activated through conscious effect. Even the Sniper bullet to the back was consciously reflected, by a passive reflex he had trained. He had a limited capacity to calculate, but it was generally significantly more than enough computational power. However, when he was reprogramming the computer virus in someones brain, he used all of his power to do so, and was unable to use his power for anything else, completely vulnerable to any normal attack during the time. Indeed, he was shot in the head, and the bullet went partly through his brain before he finished and reflected the bullet. He suffered brain damage, and was severely weakened. With their "my phone is more powerful than your supercomputer" (an actual quote in the series, reworded a bit) level technology, they had a way to work around this brain damage, but when the device ran out of battery, he was unable to even speak, let alone use his superpower. [Answer] As far as I can see he has a lot of weaknesses: * His only strengths are against big bulky slow attacks like hitting him with a steam-roller and then he has to be prepared. + He can only change the vector whilst he is in contact with the object so has to have very quick reflexes to stop anything moving fast. + Shooting him would be easy unless he can spot the bullet, know exactly when it will hit him and time it just right to activate his power. If you want to give him super reflexes: * Hit him in the dark. * Hit him when he's asleep. * Sleeping gas, then hit him. * Whilst he is under the effects of sleeping gas you could tie him up. + Tying him up will mean he has no vector to negate unless he wants the rope to pass through his body....sound rather messy. * Burn him (he can't stop all the molecules at once) * Freeze him. * Acid. * Poison gas. The lists go on but unless you're giving him super reflexes he only has limited actual uses for his power. ## A point to consider with his limits: Storing energy increases your mass The stock physics equation sci-fi turns to is: $E=mc^{2}$, or rather, in this case $m=E/c^{2}$. So you'll probably realise $c^{2}$ is pretty big ($9\times 10^{16}$) and so he can take rather a lot of energy before he starts to feel it ($9 \times 10^{16}J$ before he gains a kilogram). This limit, therefore, only comes into play if we're considering *large* amounts of energy. Now you're probably thinking: *"Pft, no problem, my guy can just counter the effects of that gravity so his bones won't get crushed"* Sure...and store that energy in himself? This results in a vicious cycle of constantly gaining more mass to resist gravity and then needing to store more energy. [Answer] There’s a limitation due to a complication that people are avoiding noticing. Kinetic energy and momentum are two **different things**. The OP talks about vectors and setting the length to zero, but the “energy” (kinetic energy) is a *scalar* value, not a vector value at all. The linear momentum, on the other hand, is a vector quantity. Consider the example of two billard balls colliding. As a model of perfect collisions there is a unique solution to how the balls roll, because only that maintain (the total of) both quantities. It is **limited** in the sense that one ball can’t just convey an arbitrary amount of kinetic energy to the other. Second, momentum vectors can combine from different directions to cancel out. The idea of storing and then calling up does not work as you suppose. Let’s say he pulls out 50 units of momentum pointing North. If he had near 0 to start with, then now he has 50 units pointing South left over. So really he can conjur up any momentum at any time and what’s left in his internal account is just for satisfying the physicists that momentum is globally conserved, and has no observational purpose otherwise. If you want otherwise, then you need to impose a *limit* on what he can store. But note again how vector subtraction works: It is a limit only if he wants to produce momentum in the direction opposite his current store, and he can reset that by producing momentum in another direction. In other words, his ability to not show any recoil will be limited. If he wants to keep throwing stuff “that way” then he needs to balance it out with throwing stuff in the opposite direction too. Or just wait 12 hours in the case of due east or west! Now his internal kinetic energy store can behave in a more straigtforward manner, since it’s a scalar and not a vector. He needs a positive stored value to draw down, to make his power work, and it’s depleted when it dropps to zero. In this account, direction does not matter. So how does he recharge that? Shouldn’t *stopping* an object consume kinetic energy from his store too, rather than replenishing it (like regenerative breaking)?. Now that you understand the need for two separate accounts of stored physical properties (one vector, one scalar), we come to the real, interesting, limitation. To manipulate objects of various masses, he needs to use both values in a controlled manner. First, you might consider limitations of his control or of the underlying ability to transfer the values. This happens in real life when a [hammer bounces back](https://en.wikipedia.org/wiki/Dead_blow_hammer) rather than delivering all its momentum and energy with the blow. If his power works “like a hammer” at the point on the object he decides, it may bounce back some of the momentum. This limits how fast he can affect the object, based on its composition and physical properties. It might also, like with using a hammer, hurt and tire him. So, a large mass covered with padding may be impossible to push rapidly enough to change the situation in his favor. Using the hammer analogy and confining application to the surface, it is easy to explain difficulties and limitations in manipulating objects. Second, the momentum and kenetic energy accounts are separately limited in what he can store. This means that objects that exceed one or the other would be a problem. A small, fast object will exceed his kinetic energy store, and he’ll have to shed it by throwing other objects away, until he runs out of other close-at-hand objects or runs out of time. A huge slow object will overwhelm his momentum store, which he’ll have to shed by throwing something else in the same direction. But it’s providing far less kinetic energy, in proportion, so he’ll not have energy enough to shed the momentum by throwing small items. He will be crushed. Finally, back to the hammer analogy. If he delivers the dose of energy and momentum off center, it will impart a rotation to the object being controlled. And *angular momentum* is **not** among his powers. So he will feel a torque recoil from this, and set himself spinning. What happens if you bounce a spinning ball? If the transfer is not instantaneous and behaves in a similar way, the adversary could throw spinning objects his way, and applying his power to them will cause the change to be other than what he intended — and as discussed earlier, this will hurt and tire him. And, he will be unable to help getting some of the spinning transferred to himself during the moment he applies his power. With the specifics in mind, other problems can be thought of. Can he stop water? No, because a hammer blow at the surface would not transfer to the bulk. Likewise, could he affect a pile of loose sand or stop millions of separate small grains from moving towards him? [Answer] Let's call your hero Vector Thief. You need another superhero with the ability to steal mountain climbers. He sneaks up on the climbers and makes them disappear, teleported to another mountain. This other hero just needs to walk around Vector Thief... Vector Thief will be forever trapped inside that circle. Why? Because Vector Thief can never cross Scalar Thief! [Answer] He seems to store this energy which in turn needs to have a storage limit. Otherwise he can walk around and stop everything moving store it up and send some massive mass fast enough that he could pretty much blow up the core of the planet. Maybe there is a limit to how much of this absorption his body can take and reached a limit that made his body turn into pure energy and burst. Maybe his weakness is someone else's ability. Since his power has the ability to steal motion and then make objects move, why not have a character that... influences space-time or someone who influences gravity? If he can steal velocity, then someone who can use gravity can add gravitational force to the object thus deadening the vector applied. If he wants to get rid of the gravity vector applied, he would have to steal the vector which would cause the object to stop on a dime as well and the 2 would cancel each other out until fatigue and or help came. With Space-time, you can alter the time and space around him. if he tries to steal energy, you can revert his being back 10 seconds to before he stole the energy but only effecting himself so that anything he stopped stays stopped and thus not allowing him to steal any vector energy. [Answer] **Discarded notions** I'll discard the notion of a storage limit. For energy conservation sake we could say he store the energy by turning it into radiation that is send via wormhole to another existence realm / pocket dimension / similar. I'll just not bother with it. I'll also discard the notion of visualization, because reasons. **Power Interpretation** *Only in contact* So, there is a flux limit for his power. He can only take vectors from thing he is contact with, so his body is a bottle neck for how much he can take simultaneously. When stopping a large solid object such a car or the aforementioned train, he is taking the vectors of the material with which he is contact with, since the train keeps pushing he keeps taking... this could put the train to stop in his tracks, but it is not stopping the engine, and any object in the train (which are beyond his touch) will still be affected by inertia. When stopping a liquid, remember that he is only taking from what he is touching... so he could - for example - calm water by touching it, but it will only be a growing volume in his immediacy. He will not calm the ocean... immediately, that may take ages. *Relativity* I'm taking that he can only take vector relative to himself. So, he will not stop the planet, for example, because he is moving with the planet. *Flying Speedster* He can store a fraction of gravity, and we can assume he is doing this all the time. This causes gravity to affect him less, making him lighter... this does not only means that it takes less energy to propel him forward (allowing him to reach higher speeds) but also that he can use that energy to gain a huge acceleration. He could even use his power to absorb the damage of the sudden acceleration, and to absorb the movement of air around him reducing air resistance and negating air friction. There is no reason why he can't use similar techniques to apply anti-gravity. *Super-strength and durability* He can use his power to apply speed vectors to objects, throwing them away as if he were super strong. Also hitting him won't help because he can absorb that too. In fact, since he can absorb gravity partially, he will be able to reduce a strong gravitational field to a normal one; in fact, by the same principia he could survive spaghettification. **Defeating him** *Note on healing*: For practical purposes, his healing is normal. Under the assumption that he doesn't have the fine control to repair tissues, he won't be using his powers to heal. So damage done, is damage done... you need to do damage by non-mechanical ways, so think about chemicals and drugs. Of course the problem is to get those into his body. *Note on freezing*: On the idea of freezing him (which admittedly is a common power), this will put him in a situation where there is little to absorb... sadly he has been absorbing gravity, and he can use that energy to break the ice. *Note on putting him on a vacuum*: How do you create the vacuum anyway? He can stop air from going away. Also, he can fly. The only variant of this that is viable is to throw him to outer space… but you can’t throw him. He has one big weak point: His mind. In particular if his power requires concentration. Also heightened reflexes are not part of his power... if his power is at least partially voluntary, you can take him down when he is not aware, for example when he sleeps. You may also try sneak attacks or deprive his senses. Furthermore if there are psychic powers that's game over. Alternatively, there could be powers that use forces outside his reach. Any non-corporeal power could be effective. For instance... can you touch spirits? If no, then perhaps summoning spirits to attack him is viable (I don't know how that works). Finally, nothing has been said about massless particles. Could he stop light? I believe this is beyond the reach of his power, so attacks based on light could be effective. This means that light / shadow based powers should be able to do damage. *Does anybody have laser cannon? If it can't burn him, it can at least make him blind.* [Answer] I will borrow from your kinetic energy note, as using vector in this case would allow for confusion with regards to the nature of vectors also including direction (which affects the addition/multiplication of vectors). Kinetic Energy is defined in physics as being equal to 1/2 the product of the mass (kg) and the square of the speed (m/s) and is given in units of joules. Your character must store this energy, which means his actions are limited by A) Amount of energy currently stored and B) The Mass of objects available to impart this energy to. For example, assuming his current store is 0 J and he robs a .357 bullet of its kinetic energy, he will now have approximately 780 J of energy in store. If he wishes, he could simply impart this energy on the same bullet for a similar affect as if it were fired from a gun. If, however, he only had a more massive object to use such as bowling ball, the result would be much different. Assuming the bowling has a mass of roughly 6 kg, the velocity of this ball once imparted with 780 J would be 16.12 m/s or 36.5 mph. This is merely twice the average speed of a bowling ball rolling down a lane, and while it would hurt, it would also not be nearly as deadly as a bullet with the same energy. Similarly, a 4-door sedan being about 1500kg imparted with such energy would only be moving at 1.02 m/s or 2.28 mph. What I am getting at is that ensuring the power user only has access to large objects which require large amounts of energy to move at any meaningful speed does two things for an opponent: 1) Drains the user's stored energy at an increasing rate and, 2) Render the power to be essentially infective from an energy-out-to-damage standpoint. Granted, this is a high situational design, but could be used to create some interesting situations. On a physiological level, the user's ability to actively manipulate objects moving at high speed is reliant on his mental power to even discern these objects and then react to them. For the bullet example, he would need to be aware of the shot in order to activate the power in time, and that's assuming his body is covered by the effect, so to speak. If he needs to touch the bullet with one of his hands or something like that, he would not only need to see the bullet coming but also be able to intercept its path with his hand, which requires very above-human reflexes and physical speed. That example boils down to attacking at extremely high speed at great range, or under the cover of darkness/surprise/smoke/etc. A final consideration would be this character's storage capacity. If it were possible to disable the power by simply overloading his ability to store or manage the influx of raw energy, then an opponent need simply able to rapidly dose out large amounts of kinetic energy at a rate greater than the user can manage. [Answer] Picking up some of the earlier comments and building on @Tmartin. KE = mv.v/2. Note that this contains vector and scalar terms. Note also that KE is relative to the coordinate frame of the observer. If my velocity vector is the same as the object's velocity vector it has no KE **relative to me** (free fall). mv is the momentum term (velocity x mass) it is a scaled vector with magnitude and direction. Changing the direction component changes the KE relative to the chosen reference frame. So, what is our superhero changing (and what is the field of action)? The possibilities are: * The mass. Probably Not. * The magnitude of the velocity vector * The direction of the velocity vector Classical physics achieves this by applying applying a force F = ma (a is a vector quantity) over a time (roughly - integrate ma over time and 1/2 m v.v is the result). If this is the mechanism of action, as already discussed, it leads to considerations about where the energy required comes from / goes to (and what is the conduit). Also if the time is short the accelerations are large. One solution might be that our hero has the ability to change the object's reference frame. ie the reference frame of the bullet speeding toward me (that I share) is exchanged for one in motion relative to me that is opposite to that of the bullet. The bullet still moves toward me but it's reference frame is moving away from me. The bullet appears to stop. How. There are more than the 3 dimensions we experience, the remainer (number under dispute by physics) are tightly curled at a microscopic scale. If our hero has the ability - insert handwaving - to cause movement along one or more of these with a small expenditure of energy then reference changed without flipping brain out of ears. What is the area of effect? I don't feel it could be contact. If it is contact what happens to the back half of the bullet when the tip in contact stops? Eventually the bullet is a flattened disc of monatomic bullet material surrounding the hero that immediately oxidises (bursts into flame). Hmm, potential for humorous training scenario. Also where does the energy of deformation come from? If it is an area effect then power development can come from increase in control of: * Affected area ( larger volume of effect) * Larger objects (more atoms affected) * Finer control (ability to affect single atoms) The power would also give our hero the ability to move very fast. Exchange the hero's local reference with that of the centre of the Andromeda Galaxy and all of a sudden moving at an appreciable fraction of c. Solve the friction problem by having any atom in contact experience a similar reference frame change (or what happens to clothes - again, humorous training scenario). However the surface of the field will be a ball of hot plasma in-atmo. This could also prevent our hero being gassed / asphyxiated. Cause the dangerous gas to rush out of the space and or cause all the oxygen molecules to rush in. Weaknesses would be related to scale / fineness of control, awareness and reaction time. * Kinetic strike from orbit at just under orbital velocity is hypersonic and transits the troposphere in ~3 sec. Gotta know it's coming in order to stop it unless there is some kind of shield in place. But you'd need to stop the whole projectile or the hero is standing beside a ball of superheated plasma. * Slow poison (but with fine control could tissue be repaired) * Directed energy weapons. Unless the hero can control photons. Does the hero have the reaction time to move a shield in place. Not in time to block a first shot. ]
[Question] [ Igbi Island, a remote island located in the middle of the South Pacific Ocean, is notorious for its extremely powerful [megatsunamis](http://en.wikipedia.org/wiki/Megatsunami), huge, deadly waves averaging 500 feet (≈ 150m), but sometimes reaching astonishing of 2000 feet (≈ 600m) that occur every week. Scientists have yet to explain this phenomena. Recently, a sensational discovery was made. Scientists found vast deposits of diamond and gold and other precious metals and stones at Igbi Island using science-y stuff. This has caused tycoons to go crazy trying to find a way to safely live on Igbi Island, so they can mine all of the precious metals and stones. Assuming that you have unlimited money (the precious stones and metals provide an endless amount of profit), modern day technology, and three tsunami-free months to build, how could you tsunami proof Igbi Island, so that people could live there? Igbi Island is circular and doesn't have any mountain ranges. There are a few small lakes and ponds on the island and one large river that splits the entire island in half. It has a diameter of 6 mile diameter, and a land area of roughly 28 miles2. There will be skyscrapers, but none will be taller than 500 feet. I was thinking that it would be near [here](https://www.google.com/maps/place/South+Pacific+Ocean/@-38.6617637,-128.5243492,3z/data=!4m2!3m1!1s0x68b8066308a0300f:0x54d79b0bb6ab56f8). The closest (owned) islands are the [Pitcairn Islands](http://www.pitcairn.pn/), but those are still hundreds of miles away. [Answer] Going with waves like @pipperchip: boats don't notice the tsunami, and even probes deployed on buoys for the purpose have a very hard time detecting it. Why would an island be bothered? Because of the rise of the seafloor leading up to the visible part. Islands that are too steep will suffer landslides until the slope is sufficient to hold. Make yours different. Diamond and island in the middle of nowhere points to volcanic origin. Diamond is found in "kimberlite pipes". Now think of another volcanic formation known on land: the *butte*. If the island is a subsurface butte, there is no rise just a sudden post. The tsunami will not form a wave since there is no shore slope. Suppose that it is a butte a bit of the way down, and your preparation is to blast off surrounding material to make it post-like sufficiently deep to be invisible to the tsunami passing. That can involve shoring up the rock face to make it stable, and adding a little technobabble: the mound that remains (say, 2 miles down) is reverse-contoured to make a moat-like ring. Waves feeling the bottom will also interact with the shape and cancel out the dangerous rise in amplitude at the spot you are protecting. Cool if it caused sudden waves in complex shapes to appear just *past* the island after it passes. As for the setting: how can regular tsunamis be a mystery? A subsea earthquake is quite conspicuous, and *whatever* it is will have a big bullseye showing you where to look. They are *global* phenomena, not just something that pops up like a spring shower. They will he hitting costland, not just vanishing after leaving the area. Your back story needs work. Also, if they are currently a problem for island settlement, isn't it swept bare and eroded off the face of the map? Why do the lakes and rivers stay stable features? How can a river cut a 6 mile island in half, without a mountain in the middle? You do know how rivers work, right? I think the idea of making the island tsunami-proof is interesting. But the rest of the setup does not hold water. [Answer] Dig into the island like underground bunkers. The island somehow survived these extinction-style events once a week long enough to become an island, it's probably already in the correct shape to handle the water. The hardest part: you'll probably need some very impressive doors. While a megatsunami is going over your head, there's 2000ft of water overhead. That's a lot of pressure! I hear they make some really dynamite doors out of unobtanium. Real sturdy. Can we acquire some of that with our untold millions? [Answer] 3 Months? Tsunami Proof city? One idea is a bit like answering "[mu](http://en.wikipedia.org/wiki/Mu_(negative)#.22Unasking.22_the_question)" to a question, but here are some solutions: 1. Make your city a series of floating boats. The Tsunami waves actually do little damage to boats at sea, they are [just large waves](http://en.wikipedia.org/wiki/Tsunami#Characteristics) which boats can ride. If you have a tsunami warning system, you get everyone to the boats, push off, and you have no effective damage when your city re-connects with itself. You have enough money to make everyone live on a boat, so why not? (It should be noted that there would be a recommended distance from the island for people to go to avoid the waves. This depends on local geography, specifically local ocean floor topography.) 2. [Tsunami barriers](http://en.wikipedia.org/wiki/Tsunami_barrier) can be made. Once again, 1-3 months is a tight deadline, but you could make walls to help deter the force of the tsunami. It may take longer than 3 months to tsunami proof the entire island, but it can be done. You can even take advantage of natural coral reefs to make this process easier, assuming that those corals exist. [Answer] Simply build large submarine(s) that rest on the island like houses. When it's safe they can act just like a house, when the water comes you have an early warning system so everyone can get inside and ride out the waves. You can either tether them to the ground or if you are adventurous let them float for a bit of excitement. The subs would need very thick metal (Titanium?) hulls to cope with the battering of debris in the waves and you'd need a lot of workers to buff out the dents afterwards. The subs could be built somewhere safer and then sailed/towed to the island. [Answer] I think you need to consider that this island is not isolated on an uninhabited planet. It's in the Pacific. Seismic waves don't evaporate after passing your island. That means these mega-tsunamis are sweeping all the Pacific coasts, because their energies, while reducing over time, are so stupendous to begin with that they will not disappear before hitting New Zealand, Australia, all of Polynesia, the Philippines, Antarctica, Peru, &c. with destructive force. They are likely to still be capable of damage when they reach California, Hawaii, and Japan. Hell, the big ones will wipe out harbors in Alaska. Weekly. They are going to have to be investigated and explained, because they are too constantly too dangerous to major developed countries. They can't possibly have gone unnoticed this long. Tsunami aren't localized phenomena: when an earthquake happens in Peru or Japan, Honolulu goes on tsunami watch (the Hilo tsunami from the Alaska quake left local civil defence permanently tsunamiphobic). We get them from all angles. *Regular* tsunami are often discernible here. Mega tsunami? Our local marine research centers would have noticed them first. I used to work at one, and the constant job of the research vessels is placing, replacing, and re-battery-packing tsunami monster buoys. For all that, the floating city that backs away when it's time for the tsunami sounds good. When the tsunami warnings go up, people here run down to the harbors to take their boats out. But check how far out they have to go. Skyscrapers of any sort are a pretty crazy idea. They're energy intensive and everything has to be imported to this uninhabitable rock. It can't provide fresh water, even. Your river and lakes just aren't possible. An island, to have fresh water, needs mountains to intercept rain and enough aquifer above the reach of salt water to hold ground water. Everything else is rain runoff from the last storm, on rock that has been swept clear of life (and soil) on a weekly basis. If the three-month clear season is when the endangered sea-mammals come to the island to breed, Greenpeace is going to be in the way. ;-) [Answer] I think you need to reconsider the tsunami size that you've stated here. Remember the 2004 tsunami that crippled south east Asia? It was really only 10 meters high...it killed over 220 thousand people at this size and effected much of indonesia and south east asia (not isolated to a single island and this wasn't even a megatsunami, megatsunami's are ocean wide events). The height of a tsunami isn't the frightening portion, it's the volume of water. To get the size of wave you are suggesting here, you need a pretty large event...30 million tons of land dumping into the ocean in one cataclysmic event should get you a wave about half the size of the small end you are talking about here...the 'astonishing 600m' wave you suggest could really only be created via an asteroid impact, and much more than your island will feel the effects of that. Subterranean earthquakes will not cause what you are asking for here. Second note is your island is far too tiny to support lakes or river ways. Rivers have to come from somewhere. The large island of Hawaii (called the island of Hawaii) is around 10,000 km². At this size (with a volcano in the center that supports a snow cap) it is barely able to support a river and most waterways are what we'd consider to be streams. Your island would likely have no fresh water and any standing body of water is likely salt water not fresh (mostly because your tsunamis here have flooded it with salt water). And third...the size and rate of these tsunamis would literally wash your island away. The size of this wave would completely submerge your island here and repeated hits would literally rub the island off the map and scatter it across the ocean floor. Actually, it'd probably do the same to 95% of indonesian islands, archipelago islands wouldn't last long like this. All that aside...lets try an answer. There is no way of resisting this wave. A wall would need to be several KM high and capable of resisting millions of millions of tons of pressure with each wave. This means any form of 'tsunami' proofing this island is going to be from the standpoint of riding out the wave and not resisting it. Submarine and boat answers have been given (I doubt the boat would quite work...a 600 meter wave would begin shaping as a wave when the sea floor is 600m deep, so unless you have a massive incline of this island to the floor, most likely it'd present as a wave long before any boat could get by it). As a last resort, I think you would be better off to maintain a large fleet of helicopters capable of lifting structures off the floor and simply fly over the wave, watch it go by, and reland the buildings (hoping the debris left is flat enough to land the buildings on). Also of note, mining operations would be completely flooded if they weren't properly sealed. If you drastically reduce the size and scale of your extinction level event tsunami described here, then there are a few other potential techniques that might work. If these tsunami's are coming from a consistent direction, it is feasible to build a sea wall in a triangle shape that diverts the flow of the tsunami around the island. [Answer] Gallons per cubic meter: 264 Wave height: 600M 264 \* 600 = 158400 gallons per square meter of water column Inches per square meter: 1550 158400 / 1550 = 102 gallons per square inch of water column Water weight: 8lbs per gallon 102 \* 8 = 816 psi static load. Typical Concrete is 2000 to 4000 psi. A tsunami applies load in multiple directions during impact, so the total live load on the structure would probably exceed the static load of 816 psi by a significant margin, but it might be doable. The surface of the island would be completely flat, whether it started out that way or not. The underground structure would look a lot like roman catacombs, or subway tunnels or a beehive perhaps. The rooms would be small, and the arches utterly massive. The impact would probably be violent enough to feel like an earthquake, with massive air pressure fluctuations during the event. Even inside of concrete you're pretty much inside a drum that is getting pounded from above. Some kind of air pressure damping system would be required, which being subject to seawater corrosion, would be very important to keep working. The floors might be suspended on shock absorbers like they do in nuclear fallout bunkers. Of course concrete has a tendency to crack, so trickles of water would be flowing in. It would be an exceedingly unpleasant experience. A lot like the movie "Das Boot" I imagine. My best guess. [Answer] Honestly the only way you are going to avoid getting destroyed by a tsunami that is 150-600m tall, is to get out of the way of the tsunami. I suggest some ways at the end. You are going to be having millions of tons of water passing over your island routinely. No matter how you shape your island or try to redirect the water you cannot actually stop the tsunami from passing over your island, if the island has a fixed location like all modern day islands. The key point to remember is that a tsunami isn't just a wave, it's a rise in water level. Behind the 150m high tsunami, is just more water that is that high. So it may take minutes or hours for the entire tsunami to pass. No matter how you try to redirect water, that tsunami is going exert extreme blunt force against whatever you have constructed, and destroy it. If you make a diamond shaped 600m tall wall, you don't know what angle the next tsunami will come from. Maybe the next one hits flat on the square side of the diamond and boom it is now gone. Even a cylinder protective wall will likely get toppled, or possibly crushed from the high pressure of being 600m under water. Plus if you have a wall that high you don't have much of an island anymore. ## So you really only have 3 options. 1. There is a closable dome over your island/city and the populations aims to let the tsunami pass over. Basically you have an underwater city one time a week. 2. Your island is (literally) a floating island. Its not really an island so much as a large boat. The boat could be anchored to an actual island, or it could just be a giant boat with enough dirt on it to sustain farming, etc. 3. This is a flying island. Stay away from the tsunami. [Answer] First--just something to think about--if you have an infinite supply of gems, the value will decrease. So, if you have a limitless amount of gems, and you start using them and selling them and putting them into circulation...their value will plummet--maybe not very fast, but over time it will happen. So planning to use these gems to fund the construction of a habitation on your island might not be the best way to go. (Of course, 99% of readers will never think or care about that kind of thing, so feel free to ignore this paragraph if need be.) Secondly, in answer to your question, I would dig some tunnels that descend deep under the island. So long as you can keep tunneling, you can produce more and more space. This begs the question, of course, of how you'd seal the tunnel off when a tsunami comes. This is very tricky, considering the force of the water and the additional pressure. However, if you could seal the tunnel off with some kind of door (made of steel or titanium, preferably), you could probably protect the inhabitants. [![enter image description here](https://i.stack.imgur.com/iF5gO.png)](https://i.stack.imgur.com/iF5gO.png) / This picture is what I'm thinking about. Assuming you get a significant warning (15 seconds, preferably more), you should be able to seal the door. Now, when it comes to protecting the people on the island, you will probably have people on the surface of the island at any given point in time. Like I said, it all comes down to how much of a warning you get before a tsunami strikes: **5-15 secs:** you will have difficulty shutting the blast door in time. **15-45 secs:** you will have difficulty getting a large crowd of people outside the blast door to safety **45-60 secs:** you will have difficulty getting people within a thousand feet of the blast door to safety **1-5 min:** you will have difficulty getting people within a few miles to safety, but it might be possible. **5-15 min:** optimal time. At this point, if you have built the door near the center of the island and the people on the surface are equipped with something like an all-terrain vehicle (and you don't have an army of people on the surface of the island), you should get everyone to safety in time. I would caution the construction of any structure of any sort above ground and outside of the blast door. With a wave that big and that powerful, it really doesn't matter how sturdy it is--it's going to get damaged and swept away. Hope this helped! [Answer] Place several rows of very large underwater airbags in the path of the MEGA-TSUNAMI. The amount or water that those airbags displace must be on the order of magnitude but larger than the volume of water in the MEGA-TSUNAMI. This should be done in deep water before the slope which causes the formation of the MEGA-TSUNAMI. Release the air at the right time to create a void which can be filled by the MEGA-TSUNAMI. This would work much like noise canceling headphones by causing destructive interference between the anti-(mega) tsunami made by rapidly evacuating the airbags and the MEGA-TSUNAMI. The subsequent rows of airbags would be to dampen the smaller tsunamis made by imperfect cancellation. As soon as the MEGA-TSUNAMI is eliminated, the airbags could be refilled with air and used again. I primarily answered this so I could say MEGA-TSUNAMI over and over again... [Answer] Don't go on the island, use submarines and sieve through all the subsurface sediment surrounding the island (bonus since it is already broken up for you). Stay far below wave base and let the tsunami do the work of stripmining the island for you. If mega-tsunami are that regular of an event the island won't be around for long anyway. The island should be surrounded by masses of submarine sediment hundreds of times is size. ]
[Question] [ Why would cities become layered without overpopulation? When I say layered I mean having a second or third ground built *above* ground level. With its own metros & roads. Most of the buildings below aren't connected to the buildings above. Zoning on the above level would be separate from the levels below & above. The layered cities don't have to go up that high, only one or two levels up. Overpopulation isn't an issue in this world. Not all cities have to be like this, only some. Large amounts of government resources are available to achieve this. Near future technology is available. [Answer] **Mixed Population Cities** One reason this can happen is when the city is home to different races. One kind of people prefers to be firmly planted on terra firma while another race is able to fly and can thus take advantage of heights. Such a situation could arise in a purely fantasy, sci-fi or mixed setting. Basically, the idea is to plan and construct cities that will cater to a variety of populations. **Limited Space Cities** Another reason to build up in this way is because horizontal space is limited or valuable. Take a citystate like Hong Kong or Singapore. Not a lot of real estate. Building a second or third tier would allow for more space for the people who live and work there. Stratification could be based on usage. You might want residential communities on the top level, where there's exposure to the climate, where they can get a sense of being "in the country" even though below their feet are several other layers of city! Commercial enterprises, sporting arenas, public venues of all kinds could easily be placed in the middle level. Services, industrial, storage and processing facilities could be placed on the low level to ease transport. **Social Stratification** The "elite" of society live on the top level where there's lots of sun and pleasant weather because they can afford to. Government officials, owners of the facilities in the lower levels, wealthy city hoppers and the modestly well to do live above. Service workers, functionaries and less well to do folks, foreign workers and the like inhabit the middle tier. They might visit the parks and attractions up above, but they have to scurry back to their burrows before curfew! Laborers, mechanical operators, industrial workers, the abandoned, the poor, the downtrodden are all trodden down into the bottom level. Some of these may only be allowed topside on holidays while others may never get to see the shining city except from outside! [Answer] Another reason is that the city is built around a ravine. For a real-world example, look at the Place de l'Europe in Lausanne, Switzerland. [Answer] **The old lower city was forgotten.** <https://en.wikipedia.org/wiki/Seattle_Underground> > > For the regrade, the streets were lined with concrete walls that > formed narrow alleyways between the walls and the buildings on both > sides of the street, with a wide "alley" where the street was. The > naturally steep hillsides were used and, through a series of sluices, > material was washed into the wide "alleys", by raising the streets to > the desired new level, generally 12 feet (3.7 m) higher than before, > in some places nearly 30 feet (9.1 m). > > > At first, pedestrians climbed ladders to go between street level and > the sidewalks in front of the building entrances. Brick archways were > constructed next to the road surface, above the submerged sidewalks. > Pavement lights (a form of walk-on skylight with small panes of clear > glass which later became amethyst-colored) were installed over the gap > from the raised street and the building, creating the area now called > the Seattle Underground... > > > In 1907, the city condemned the Underground for fear of bubonic > plague, two years before the 1909 World Fair in Seattle > (Alaska-Yukon-Pacific Exposition). The basements were left to > deteriorate or were used as storage. Some became illegal flophouses > for the homeless, gambling halls, speakeasies, and opium dens. > > > Your layered cities are like this. The old cities are still down there. New things were built on top by new governments wanting city renewal, conquerors establishing primary, disaster remediation or what have you. Whatever remains below was left to be repurposed or used as people will. These areas are not formally under the control of the topside government. Different governance structures prevail in the undercities. There have been some very cool articles about this layered aspect of Istanbul. There is a lot of stuff underneath that city. <https://www.dailysabah.com/life/history/istanbuls-mysterious-underground-waterways-pictured-for-1st-time> [Answer] * people are trying to out-compete one another; "no, **MY** building is bigger!" "no, ***MINE***!" * social reasons, where being at the top is seen as prestigious * the cities flood on a regular basis, and the bottom floors are used for aquaponics * a large number of hostile creatures roam the land, the ground is too hard/mucky to dig bunkers and basements into, and so people go up rather then out so that the amount of building touching the ground is at a minimum * travel by personal airship is common, meaning that buildings need to be tall for airships to dock next to them * they're trying to grow crops on the sides of the buildings, and building them taller maximizes surface area exposed to the sun * buildings have mirrors on the side to support [solar furnaces](https://en.wikipedia.org/wiki/Solar_furnace) * larger buildings have more volume rather than surface area, making efficient housing and office space; since building out causes competition, building up is the next best option for increasing volume * it's just a popular building style [Answer] # Near-Future Construction With near-future technology, new types of materials have become suitable for construction. In some cities, the ground beneath them is suitable. Instead of expanding cities and destroying the beautiful countryside it has become convenient to dig down and create a new city layer below. The original infrastructure is maintained, as much as possible. The material liberated is then used to create a new top layer on top of the original layer. # Quirks of Planning Permission and Land Rights Land owners in your world have land rights that extend indefinitely upwards and downwards. For whatever reason its difficult/expensive to purchase or build on new land, but its permitted to make modifications to your own land. Land owners tend to be wealthy. They pay no tax on the land they own, and they charge rent from anyone who wants to live on their land below. The rest of the population don't own any land and are obliged to live and pay rent on the middle and bottom layers. [Answer] ### Cities are sinking. Capitalists solution: sell a new real estate, layered on top. Most modern cities are built near large body of water, so I think this works? --- The city is sinking. The capitalists do not care about investing for returns that 1) come in a very long time and 2) not in the form of money, so they ditched the idea of environment-saving projects entirely. **How can I make money on this situation? AHA!** The big players of the city land management i.e. shortsighted planners, (possibly bribed/lobbied) government agencies, real estate investors, think it's just in their interest to stack another layer on top of the existing city. "Grand new real estate, prestigious because why not, and sells at very low price of one billion dollars!1" Said their advertisements. Sure, it will be expensive to build this one massive concrete bed2 several dozen meters in the air. But don't worry, it will be built by siphoning government subsidies! Of course, the revenues will benefit the capitalists.. It will be an overpriced megablock for the first buyers, but the capitalists will keep advertising and growing this "new layer of city" thing. Common middle-class people is "lured" by the idea of prestige or decent, comfortable living on this new area. Supply and demand (plus maybe competition to sell this new hyped area) will drive the prices to somewhere within reach of upper-middle class, making the area the "dream" for middle and lower-class. Fast forward several decades after this boom: the city now has an upper layer of concrete, with the richer families of the community naturally being/wanting to be on the top layer. The capitalists made their fat stacks, the city is sinking even more, but hey, who cares about those peasants? "If they want to live in the comfortable, currently-far-from-sinking higher area of the city, they should work hard, invest, make money, etc etc to get that! Decent life comes with hard work!" The lower part becomes a swampy wasteland just several more decades later.. --- 1 Just an illustrated price for some terribly overpriced real estate but still within reach of some very rich people. 2 Could be concrete, could be handwavium. Could be very expensive, could be moderately expensive. But the idea stands. [Answer] **Efficiency and specialisation** High population density is more efficient. Average commutes are very short and a very specialised society needs a lot of interactions. Stratification might be due to some special functions being assigned to each level. Overpopulation might not be there, but a government planning every detail might still take it into account as a possible future (or past experience?) problem. **Overplanning** The above city implies a plan made in advance in every detail. It is a lot more different than the current cities which start small and grow in a chaotic manner. Even a plan like the one done for [Brasilia](https://en.wikipedia.org/wiki/Bras%C3%ADlia) would not be detailed enough. It must be a city designed in this way and built in this way from scratch. [Answer] ## Demands for surface land: In your world, there is something special about the surface that makes its usage in high demand. Perhaps there is a valuable agricultural product that only grows on this world, and is exported to other worlds/off-world colonies. Or the production is inefficient, such that vast quantities of production are needed to make small quantities of the final product. The form of the substance is open to interpretation - imagine, for example, a drug that infinitely extends life, but requires greater and greater doses as people age. The profit from this would be so high that every available inch or arable land would be used for crops. Your cities would be off coasts, over mountains, or centrally located for the industrial demands of processing the crop. Another alternative is that the people are extreme ecologists, and are desperate to maintain a minimal impact on the environment. Hyper-urbanization could be a model the government is trying to encourage, so other cities adopt this and become less of a disruption to the ecosystem. As a result, people cluster into dense population centers. But since we want to entice people to live there, we create entirely new levels to allow folks to enjoy a less-dense lifestyle while still increasing the density of the cities immensely. * Another reason for this is seen in Minneapolis. The city built a network of skyways in the city buildings so people didn't need to expose themselves to the harsh winter weather. As a result, the second floor of most buildings instantly became the most valuable real estate in the buildings. Your city dwellers could have some unpleasant environmental factors that have encouraged people to network between large structures, then gradually enclose platforms to make a new layer. Once this happened once, developers might do it again to try and repeat the success. [Answer] # Extreme Weather Imagine a world where the outside weather is generally too hot / too cold for people to survive very long unprotected. And which also includes powerful hurricanes/tornadoes. This does two things: 1. Since living almost entirely indoors with windows that don't open is normal, living in a middle of a giant city-block with virtual windows instead isn't much of a downside. Some people may even prefer it, perceiving it as safer. 2. If the hurricanes are powerful enough, a single large fortified block can probably withstand them better than a bunch of separate buildings. To limit the area which needs to be build, the multi-floor design could make sense. If you go into future technology, you could also have weather control facilities which dampen the effects of extreme weather, but only in a limited radius, and are vastly expensive to build/operate, such that it's worth building multi-level to fit the city in the radius of a single one. [Answer] ## Economics With all of these, they will happen if it makes economical sense. If it costs more to have layers with no benefits to have layers it won't happen. On Earth, what happens in lower layers will affect the upper layers. If the lower layer can't support the upper layers it would be disastrous. This would mandate strict building and engineering considerations which can be costly. ### The atmosphere is really cold or toxic etc This would require cities to be enclosed. So the city is more likely to be an archology/megastructure then a collection of buildings. ### Underground is cheaper then above ground. It is economical to build deep, Ie in a large asteroid or small moon, once you get beyond some number of layers there will be specific layers that interconnect the city. When building underground layers are best way to go. This happens with large coal and salt mines that are not pit mines. ### Already tall structures Super tall tree world. I.e. trees that are large and hundreds of meters tall. So it costs less to build with the structures then to remove them and build. Multiple layers will form when it is more efficient to have transport layers at multiple certain heights then transferring up/down to one transport layer. [Answer] Maybe I'm misunderstanding the question but I believe there are many cities that are already multi-level although most are not usable anymore. Such as New York, Paris, London, Rome, etc. where newer cities are built on top of older cities. But there are several cities that are true multi-level metropolises. This usually occurs when cities are built near rivers or the confluence of rivers that flow through mountain valleys or gorges. The original city is built on the lower level or river plain and as the city grows outward it also grows upward along mountain terraces, flats, plateaus and valleys using roads, highways, bridges, tunnels, walkways, and elevators of all types to create and to gain easy access to new areas. One such city is [Chongqing in China](https://www.youtube.com/watch?v=SF3Tie2C720), but it's nowhere near the cities of Coruscant of Star Wars fame or night city of Cyberpunk 2077. I don't think anyone would want to live on the lower level of a city that has the entire sky blacked out by a city built, somehow, right above them. No, that type of layered city would only work in the movies. [Answer] # The City is Ancient The city has been in the same place for a many years, and the material the city is built from is very sturdy, and the city grows higher and higher on the foundations of what came before. City farms require large aerial platforms to be built, to capture the rain and grow crops, and parks for people to enjoy the sun. A conflict might develop between the farmers and the solar cells required to power the machinery This might work well with a Science Fiction story related to unlocking immortality. The technical problems of how the lower levels would continue to thrive would be interesting. Mushroom farming might become critical. You might also have some people burrowing lower into the earth for warmth, the lower they descend, the warmer it gets. Perhaps the mines that supply the city with materials are directly under the city itself, and everything is cross braced. [Answer] Crazy wind! In this scenario, wind speeds in the planet are so high that building skyscrapers is nearly impossible. To accommodate, cities are built in humongous layers to provide the same population density but in a lower form factor. [Answer] ### Transportation is expensive Elevators (even muscle powered) are highly efficient means of transportation relative to going overland or oversea. In a world with unreliable or limited telecommunications and limited energy supplies, this advantage is particular important. ### Population density is efficient There is a well established relationship that is extremely robust in economics between population and per capita productivity. Putting more people close together increases everyone's per capita productivity and hence per capita income on average. [Answer] ### Majestic views! I used to live in a seaside town and the increase in rent for a flat with a sea view was substantial. If a new building was erected blocking your view, it could wipe 25% off the value of your property - not to mention the mental anguish of seeing their *stupid new building* where once you had an uninterrupted view of the gulf. Everybody in your town wants a sea view. Or a mountain view, or a view of the ever-orbiting Seven Moons, or of the Whale. Technically, there are regulations for obstructing another’s line of sight, but the wealthy and influential know how to pull the right strings. The palaces of the highest-ranking families rise the fastest, turning into ornate towers frothing with balconies and turrets and increasingly shaky buttresses. The middle classes cram into tight apartment blocks where each family gets exactly one window towards the view. A lot of the undercity is empty - whole mansions abandoned when they fell behind another building’s shadow. It’s pretty nice for squatters, as long as they don’t expect the water pipes to be still functional. ]
[Question] [ **This question already has answers here**: [How would you bring wealth back to the past?](/questions/113986/how-would-you-bring-wealth-back-to-the-past) (22 answers) Closed 3 years ago. Congratulations! The year is 2030 and after a few months of waiting on a list you've been chosen to become one of a select few individuals who will be allowed to time travel to your chosen year of 1890. As you don't want to be left empty handed, you've chosen to take with you about \$10,000 in 2030 USD (around \$7800 in 2020 USD with an inflation rate of 2.5%). According to some quick searches \$10,000 in 1890 would be closer to \$363,000 in 2030, given the 2.5% inflation rate. However, the currency in 1890 is physically very different from the modern dollar bill, as the modern federal reserve was only even founded in 1913. As such, you'll have to find a way to turn your $10,000 in modern bills into a similar face value in 1890 in order to multiply your purchasing power. Some other details: * Assume that the bills in 2030 are the same ones being used by the USA in 2020. * You can make multiple jumps to different time periods, however because of the amount of power required, each additional jump to a different time will cost you about $500 in advance. You can however control when you choose to make each jump without needing to schedule a time. * You are allowed to exchange your money for other goods, but the time traveling system will only allow you to bring along a large backpack of items. You can make multiple trips it will cost you the price of extra jumps. * You can go forwards in time as well as backwards but you can't travel into the future past 2030. * You're only able to time travel, not teleport. This means that when you jump through time you'll end up in about the same place you started. This means you must be able to walk wherever you need to get to or pay someone to take you there. Your starting place is the middle of Chicago. * You cannot get caught exchanging new currency that was printed in the future for older currency (such as trading a 2030 dollar bill for a 2005 dollar bill). You can do it, you just can't get caught. * There's no magic technology in 2030 that can convert your \$10,000 into a face value of \$10,000 in 1890 bills. [Answer] I'm not sure what what plot points you want to make in your story. > > There's no magic technology in 2030 that can convert your 10,000 into a face value of 10,000 in 1890 bills. > > > There is no magic, but there is technology. The facility providing the time travel service will have counterfeit currency for the decades of interest for the various destinations making use of craftsman experienced in engraving plates for paper currency, knowledge of paper and coin alloys, and computer printing technology. Paper currency isn't that old, and coins would be primary. Previous time travelers will have returned with real currency after trading it with valuable metals. The chrono agency could provide all the way from gold coins down to cowrie shell currency. You mentioned: > > This means you must be able to walk wherever you need to get to or pay > someone to take you there > > > Gold dust, flakes, and nuggets in various sizes will translate into almost any language in any time period. Beads, jewelry, fire starting kits, and clothing could be used for trade with tribal communities. [Answer] **Make your fortune in aluminum** Here are the rules I'm interest in: > > You can make multiple jumps to different time periods, however because of the amount of power required, each additional jump to a different time will cost you about $500 in advance. You can however control when you choose to make each jump without needing to schedule a time. > > > You are allowed to exchange your money for other goods, but the time traveling system will only allow you to bring along a large backpack of items. You can make multiple trips it will cost you the price of extra jumps. > > > You can go forwards in time as well as backwards but you can't travel into the future past 2030. > > > Aluminum in nice clean ingots is about [1 dollar per lb](https://www.statista.com/statistics/209336/price-of-aluminum-on-the-us-market/). A 90-liter backpack can hold roughly 5500 cubic inches, and at a density of 0.098 lbs/cubic inch, that's about 539 lbs of aluminum, and will only cost you 539 dollars. It's a lot to carry, so hire a Sherpa, or maybe attach some wheels. Now, spend an extra 500 dollars time travel back in time to 1852. (It's allowed! You're just not permitted to go *past* 2030, but the rules say nothing about going further back.) Aluminum, in the US in 1852, was [34 dollars *per ounce*](https://books.google.com/books?id=vQUEAAAAMBAJ&pg=RA1-PA29#v=onepage&q&f=false). You have 8624 ounces of the stuff, giving you a total *equivalent* value of 293,216 dollars in 1852. Now, simply jusmp forward in time to 1890, and now you have approximately 290,000 dollars of 1852 American currency, perfectly usable in 1890, for only 1,039 dollars. [Answer] Buy gold. Take it back to 1890. Sell it. You’ll get about 1/80 as many dollars as you pay for it (at 2020 prices), so \$10,000 becomes \$125. (Don’t try this trick if you’re travelling to a time between 1933 and 1974, when private ownership of gold was largely illegal in the US.) [Answer] **Buy some coins** A quick search on Ebay today shows that a single 1890 Morgan Silver Dollar is going for about \$20. $10k will net you about \$500 in 1890 money. \$500 in 1890 translates to about \$14,000 in 2020, so just go to Ebay with your 2030 money, buy some 1890 coins, jump back, buy \$500 worth of stuff, and jump forward and sell it. **But you can do better.** You can request certain types of coins from the bank. The trick is knowing what coins to ask for... and when to ask for them. Case in point: The Susan B Anthony dollar was minted from 1979 to 1981, and then again in 1999. So if you go to 1998 and request Dollar Coins, you can get them with ease. You might need to do some legwork, such as making a bank account for a fake business that deals with vending machines, but it's not difficult. Then you can go back to 1982 and do similar. **But. *You can do better***. In 1865, the Secret Service was created. To suppress counterfeit currency. Upwards of one **third** of currency in circulation at the time was fake. Counterfeiting these early US Dollars was fairly easy as they were largely just... paper. The methods used to make them aren't particularly difficult to find and are rather well documented. \$10,000 in 2030 should be able to get you a setup to be able to make a *significant* amount of late-1800s bills that would pass inspection. Then, with your likely arbitrary amount of fake money, you can go back to the 1890s and cause havoc with whatever economy you so desire. [Answer] **The boring, iterative way.** 1. You are in 2030. 2. Change out your money for small bills. 3. Select the oldest 10%. Exchange the rest for large bills. 4. Exchange large bills for small bills. 5. Goto 3. Repeat 10 times. 6. Jump back to the oldest time your bills would be legal tender. 7. Change out your small bills for large bills. 8. Exchange your large bills for small bills. 9. Select the oldest 10%. Exchange the rest for large bills. You get the idea. I think all paper money has dates but US paper money does not have issue dates like coins, only series numbers which helps this endeavor. Of the US bills in my wallet right now about 2/3 are series 2013 and 1/3 series 2009. I could jump to 2014 right now where none of the money I have would be surprising, or do a few changes to get all series 2009 and then jump to 2010. At either of those previous years I could accumulate series 2003 bills then jump to 2004 with them. Chicago would be a fine place for this. People might look at you weird in the bank sorting thru you piles of paper money but it would be a safe place to do it. Nobody would notice you doing it over and over because the next time you did it would be earlier than the time before. [Answer] **Pick other currencies that had a large inflation rate at each jump** By going back in time, you experience a kind of **reverse inflation**. Doing this only with dollars only sucks. Bolivars would be a much [better](https://www.exchangerates.org.uk/USD-VEF-exchange-rate-history.html) choice for the last 5 years, the Deutsche Mark in the late 1920s, ... Here is how it works. 1. Change your dollars to Bolivars (let us say 1 dollar = 1000 bolivars at that point). Go back to a point in time where the bolivars you have are still exchangeable. Exchange back to dollars (let us say now 1 dollar = 10 bolivars) (eventually on the black market, see point below). Congrats, you are now a millionaire! True rates would even make you a billionaire in a few years. 2. Exchange your dollars back to a lot of older, smaller banknotes of bolivars. 3. Go to 1. You even have a long list of [hyperinflation episodes](https://en.wikipedia.org/wiki/Hyperinflation) where you can do this. Some restrictions apply of course. But the earning you can make will sure be worth the plane tickets you will have to buy. **When the physical currency changes, make sure to stop when both are valid** There is always a period when both currencies, the old bill and the new bill, are valid. Stop by and get only old ones. The same principles applies when a larger bill is printed (for instance the 100 000 bolivar/Deutsche Mark, ...). Stop by and get old, smaller ones. **When jumping between currencies, make sure you have an exchangeable one** In some countries, foreign currencies have to be exchanged on the black market. You may be charged more than the official rate. But who cares, you are already super rich due to reverse hyperinflation. [Answer] Everyone is missing a step here. I'm not American so I can't tell you who is the best artist that was alive but relatively unknown in 1890, but wikipedia can help: [Artists born before 1900](https://en.m.wikipedia.org/wiki/List_of_American_artists_before_1900) So find the artist that has the highest current (2030) average sale price per painting that is within a short trip from Chicago, that is also relatively unknown im 1890. But every scrap he has. Get a receipt, hell, get 2 and leave one somewhere it'll get catalogued (tax offices?). All of these paintings will fit inside a backpack without any real issue (remove frames etc.). Now go back to 2030 and sell, sell, sell. After this you could then go back to 1890, but really, why bother. You're one of the richest art dealers in the world now. Go buy an island. ]
[Question] [ *(For ease of reference, ECT aircraft are the drones, SEDA aircraft are the manned jets)* I have the same problem as [How to keep humans pilots instead of AI in a sci-fi future?](https://worldbuilding.stackexchange.com/questions/17043/how-to-keep-humans-pilots-instead-of-ai-in-sci-fi-future), except I have a few problems with applying the answers to my world. Though they're very good answers, the main issue lies in that in my world **the aircraft are not autonomous, but rather each one is individually remote controlled by a human operator based in their home nation.** So my question is this: What benefits, if any, do manned aircraft have over remote controlled ones? Some things to consider: * G-Forces aren't an issue for the SEDA pilots, as liquid Handwavium is pumped into the cockpit which negates the effect * These aircraft are only operational in Atmosphere * Combat only takes place at short range, WW2-styled dogfight distance. (Handwavium again) * SEDA could manufacture and deploy their own drones, but choose not to because of [reasons I'm hoping this question will answer] I'm very grateful for any help on this, and if I'm too vague or need me to elaborate on something let me know and I'll try to fix it. [Answer] I'm somewhat grinding my teeth with all this handwavium around, because it's just as easy to handwave the reason for using pilots if you're going to do everything else by handwavium. Anyhow ... Pilots have only two advantages in practice in your world : * They're the only way to give your aircraft independent control when comms break down or are jammed. Any remote control system is immediately vulnerable to attacks on it's comms, including boring old jamming. * Pilots can in principle override what would otherwise be automated instructions. This is both a plus and a minus. E.g. "I'm aborting my attack because there are civilians in the target". Now depending on the circumstances that could be either highly commendable or a court marshal offense, but a human pilot can make a decision about this which may not be apparent or as emotionally involving for a remote operator - seeing things on a screen and being there are two different levels of emotional involvement. Likewise a pilot can try and pilot an aircraft back that would otherwise be lost as automated systems simply were not able to improvise enough to keep it in the air. There is another approach to your needs : * Honor demands a warrior in the action risking his or her life, not sitting in an armchair chatting with his friends. You need possibly a martial culture for this. Remote control weapons might be an issue for a martial culture in this context. ... or .. * *Law* demands a weapons system is manned by someone physically present at it's firing. Could be a "Geneva"-like treaty thing or could be a law your own faction has for some historical reason of it's own. [Answer] Your situational awareness when sitting in a cockpit is *vastly* superior to that of a drone pilot sitting on the ground looking at an information feed. This is especially true in a Charlie Foxtrot of a dogfight, which conveniently your handwavium calls for. There's also an issue of latency. Drones have to relay information back to home to make decisions. If you ever play a 1st person shooter, you are *intimately* aware of how much of a difference a good ping makes. Being in the cockpit is pretty much the best ping you can get. Finally, it's possible the tactics support the conservativeness of a pilot whose life is on the line. There are some environments where boldness is punished. If your particular handwavium dog fight is one of those, it may be easy to coax the drone fighters into weak positions because the drone fighter just has some of their nation's material on the line, while the pilot has their own life on the line. [Answer] From the question I inferred that ETC and SEDA are the two opposing parties? If not then drop a comment and I'll edit. It would solve your problem if ETC has **better technology**. Maybe they already solved the issue with communication (how to keep it constant and safe from distruptions) and SEDA hasn't. Maybe ETC has specifically invented technology to distrupt SEDA communication and the SEDA pilots are frequently left to fend for themselves. Another difference could be **cultural**. Maybe SEDA are proud of having many good pilots and having a strong men and women who can withstand G forces (maybe they were even bred for it) and look down on those punny ETC weaklings who remote-control a drone and call themselves pilots. Then there could also be an **economic** difference: for ETC, building drones is not much of a cost, they are expendable. But their pilots are not. They have put a lot of time and money into their education and training and maybe not a lot of people want to be pilots so they don't want to lose any of them. In SEDA's case, everyone can be a pilot, especially if they have a cultural motivation to become pilots because pilots have good social standing and become heroes. On the other hand, they don't want to lose their aircraft, and having an on-board pilot motivates people to not just leave it behind but bring them back in good order as they can't just stand up from a comfortable chair and go home if the plane itself doesn't come back. Or it could be a combination of all three. [Answer] The best reason to have human pilots, when the factions are roughly equivalent? You're trying to *counter* the remote drones. ECT has already gone all-in on drones, the answer isn't necessarily to switch to drones and try to catch up - ECT will have the advantage having already retooled their factories and refined their drone designs. (It could be the answer but that spoils the premise) Instead, SEDA takes advantage of the inherent need for a drone to have a remote link. Missiles packed with radio-interfering chaff. High tech electronic warfare suites. EMP missiles. A manned fighter can shield against this - a remote drone can't shield its antenna(e) For SEDA, manned fighters are the best option. They can fully EMP shield their own fighters then jam as loudly as they please, knowing their own fighters will be less affected and thus gain the advantage in a given battle.\* There are a number of other smaller advantages (like reaction time being necessarily shorter being in the plane vs being 1000km away in a bunker, cheaper sensors in the form of the pilot, drones vulnerable to decapitation strike in remote facility) and disadvantages (a drone pilot survives their plane exploding) but how exactly those stack up and balance out in the end is up to you. \*I discount here effective AI driven piloting as a major factor, as you've already specified - that would invalidate the premise altogether. If they exist they must be significantly inferior to a human pilot because otherwise even remote drones are gone [Answer] The enemy makes extensive use of decoys and diversionary tactics so the SEDA pilots require a high degree of natural intuition and strong critical thinking skills so as not to waste their bombs/ammunition. Before they attack it's also very difficult for the ECT to detect them so by tricking them into attacking the decoys the ECT can locate and repel their enemy before taking any meaningful losses. When the ECT is attacking the SEDA the rough terrain and heavy cloud cover puts their massive formations of cheap drones at a disadvantage against the SEDA's smaller force of more expensive but also significantly more capable fighters, like how the Spartans held off the Persian army in the movie "300". In the open sky a swarm of 2-3 slower less maneuverable drones would easily win a dogfight against a single faster more agile fighter because they can work as a pack, in the relatively tight confines of a mountain range with heavy cloud cover they can't benefit from this cooperation. [Answer] Combined operations, especially w.r.t. communication. Human pilots are able to **talk** to air-controllers, ground personnell, etc. While AI might be good at operating on its own, however, imagine ground infantry trying to call in an air strike. Under fire, soldiers might not be inclined to interact with a chat-bot; let alone a voice recognition system with gun and artillery noise in the background. [Answer] The most obvious is when there is no communication AKA jamming or radio silence. The other advantage is they more resistant to hacking. The pilot is right there which means they can operate during radio silence and can't be jammed. Other than that, there is no real advantage. Drones still have human pilots that see through the same sort of sensors. [Answer] How remote is remote? On earth you could have up to 0.1 second latency in response time just from speed of light limits, plus whatever additional latency the protocols, routing, etc. add. In the type of dogfight combat you're looking to have, that's easily the deciding factor. Of course it could be considerably lower if the operator is nearby (at least on the same continent) as the drone. On the opposite end, if you're dealing with space-scale distances between drone and operator, remote control drones are just completely out of the question. They'd be destroyed before the operator even knew they were being attacked. [Answer] All remote controlled devices can at least be interfered or jammed. At worst, they can be hijacked. If this is a near future then jamming tech is so powerful that the only way to pilot a SEDA over the enemy territory is to make it completely sealed to electromagnetic waves and EMPs and have a human pilot inside. You can also put a smart autonomous AI robot inside and make a fleet of them, but then this becomes an issue of AI vs human intelligence. If this is the near future you can argue genetic manipulation increases human capacity exponentialy. Surpassing even the smartest AI. ]
[Question] [ **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. I am trying to build a hard science-fiction world where the interstellar travel might work like this: * Travellers bodies are scanned and all relevant information regarding body structure, neural connections, chemical concentrations, etc. is stored. The body of traveller is then destroyed. * The information from previous step is modulated on a EM wave and beamed towards another star. * After some time, the beam is received on the destination. The organic body is rebuilt from the demodulated information and the traveller steps out. To make sure that this is the right fit for the story, I tried working out the equations of special relativity *(Disclaimer: I am not a physicist)*. However, since the value of `1-(v²/c²)` becomes zero at `v=c`, I can't quite figure out what relativistic effects like time dilation will happen to the people when they are being *communicated* this way. And since it's a static copy of the traveller being sent and not a working simulation (meaning they won't be *experiencing* time or anything else), will relativistic effects even matter? Can someone please help me in working the mathematics or give me a few pointers on how to figure this out? [Answer] The speed of object with mass is expressed relatively to the limit of speed: $c$ - speed of light. The time dilation, length contraction and mass-increase effects, expressed through the relation: $\gamma = \frac{1}{\sqrt{1- \beta}}$, where $\beta = \frac{v^2}{c^2}$, apply on moving objects (with mass), not light (as it has no mass) and that is why immediately after the information, once stored in mass, is converted to light, it will not be affected by *"the movement of light"* itself. One possible change that can occur with the information, now stored as light, is change in frequency (relativistic Doppler Effect), if the sender and receiver move with respect to each other. --- Lorenz factor: $\gamma = \frac{1}{\sqrt{1- \beta}}$ [Answer] This has nothing to do with speed of light and, indeed, with any possible means of transmission. You are effectively "backing-up to storage" whatever you need to transmit and then "recreate a perfect copy" some time later, possibly in a different location. Actually it doesn't even matter if you destroy the "original" or not. In this condition you can even think about making more than one "replica" in the same or in different places. Back to your question: after you destroy the original it doesn't exist anymore. * It can't "feel" anything, not even the flux of time, because it simply doesn't exist. * What you have left is a bunch of data, which, obviously, is dead matter. * It doesn't matter what you do (for how long) with the data, as long as you preserve their integrity (which might be difficult for many reasons, including Heisenberg Indetermination Principle and trivial quantization errors). * When you recreate your "copy" (or copies) it will start behaving as-if it was right after the "scan" phase (if it is a different time from "destruction". * On the subject a nice reading is an [article by Larry Niven](https://www.scribd.com/document/106876485/Niven-Larry-Theory-and-Prctice-of-Teleportation-The). Note: all this under the assumption (IMHO correct) of a mechanistic and non-dualistic interpretation of "mind" (i.e.: no "soul" to speak of); otherwise a whole new can of worms will open up. [Answer] There are no relativistic effects. This is a pedantic answer directly addressing the OP's question. The encoded information is effectively a snap shot of the person. A snap shot image doesn't experience anything. It's simply a signal travelling across interstellar space. The person is simply reconstituted from the information in the encoded signal. The only effects could be due to the method of transmission. Errors creeping in caused by distortions to the signal as it travels to its destination. The other sources of error can occur are during processing the information of the person prior to their disposal and transmission and during their reconstitution. These are only problems of a teleportation system of this sort. Paradoxically this form of teleportation is often called 'matter transmission' yet no matter is transmitted only information. Matter at the transmission stays put and matter at the receiving end is assembled to recreate the traveller. [Answer] In the photon's frame of reference zero time passes between creation and destruction. It 'sees' the universe as being zero size in the direction of motion. So your traveler doesn't experience anything in transit. Alternately: You scanned him, the scan is spread out in time while being transmitted, he's recorded and rebuilt. Analogy: You take a laptop, hibernate to disk. Transmit the information on the disk to Paris, where they encode it on a hard disk, stuff it into the same make laptop, and hit the key to restore from hibernation. [Answer] Just stop and think about this for a moment, and you will have your answer. Our modern communications system is sent over fiber optic. Essentially, at the speed of light. We talk to each other over transmissions that travel at the speed of light. Computers interface with each other at the speed of light. YouTube videos are sent at the speed of light. X-rays and other diagnostic imaging are sent over fiber optic. Robotic surgeries are being conducted over the internet, where the data is sent at the speed of light. I do not recall that there has EVER been a relativistic effect in any conversation I have had over the internet. No uncertainty principle, either. 100% accurate data transmission. There is nothing to figure out. You are over-thinking it. We send data all the time at the speed of light, with no relativistic effects. All you are doing is sending data. However, there is a glitch in the system. The body is not scanned instantaneously, nor is it reconstituted instantaneously. The data, in its entirety, sent serially, is not instantaneous. It takes time to send the entire file. Unless it is sent with every data bit in parallel (a massively huge data transmission infrastructure) it will take time. Even when we send a file over the internet at the speed of light, we are still limited by 'download speed' - the speed at which sequential bits can be sent. The entire process, from beginning of scan to final replicant, is not done 'at cee'. Just stop and think of exactly how huge this data file would be, and how fast the download speed would have to be in order for it to be dome in a reasonable time. [Answer] I advise you to read the story called Rogue Moon. It has VERY similar theme. > > Dr. Edward Hawks runs a top-secret project for the U.S. Navy, using > the facilities of Continental Electronics to investigate a large, > deadly alien artifact found on the Moon. Volunteers enter and explore > it, but are inevitably killed for violating the unknown alien rules in > force within the structure. Hawks "must continue to send duplicates > into the artifact, however, because each one moves a little closer to > finding a way through the alien labyrinth"[3] and, thus, closer to > understanding what it is. > > > Vincent "Connie" Connington, Continental's head of personnel, tells > Hawks that he has found the perfect candidate for the next mission. > Connington is amoral and manipulative, openly testing Hawks and anyone > else he meets for weaknesses. He takes Hawks to see Al Barker, an > adventurer and thrill-seeker. Hawks also meets Claire Pack, a > sociopath of a different kind. Where Connington covets power, and > Barker seems to love death, Claire enjoys using sex, or the prospect > of sex, to manipulate men. Connington wants her, but she stays with > Barker because he has no weaknesses in her eyes. Hawks has to appeal > to Barker's dark side to persuade him to join the project. Claire > tries to get under Hawks' skin while simultaneously playing Connington > off against Barker. > > > Hawks has created a matter transmitter, one which scans a person or > object to make a copy at the receivers on the Moon. The earthbound > copy is placed in a state of sensory deprivation which allows him to > share the experiences of the doppelgänger. However, none of the > participants have been able to stay sane after experiencing death > second hand. > > > Barker is the first to retain his sanity, but even he is deeply > affected the first time, exclaiming, "...it didn't care! I was nothing > to it!" He returns again and again to the challenge, advancing a > little further each time. Meanwhile, his relationship to Claire > deteriorates, even as Connington continues his disastrous attempts to > win her, at one point receiving a severe beating from Barker. > Eventually, Connington announces he is quitting, and Claire leaves > with him. > > > ]
[Question] [ An airborne disease with an incubation time of 18 years goes unnoticed, but spreads across the world. 18 years later, its "timer" goes off, killing all adults. Good idea (thanks, @Morfium !), but I have some concerns. Would it not spread to infect those under 18, thus killing them after another 18 years of incubation? I need my characters to be able to survive past 18, which is not possible if the disease affects a large majority of them. Could I use the logic that those born after the initial wave of the disease got natural immunity from their mothers, and therefore are affected but not killed when the disease is finished incubating? To clarify, the story is about a society of children attempting to survive and rebuild after the death of all adults due to a worldwide plague. [Answer] The exact mechanism can be left up in the air. It is not necessary for your story. You can have some disaster in a bioweapons facility. The scientists think - "no harm done". Then the badness comes home to roost 18 years later. Leaving it not entirely fleshed out is a fine way to do it if your story is from the viewpoint of the kids after the fall. They would have no way to know exactly what went down. Theories from grownups might be in the news for a week or 2 but as civilization falls that will stop. I can envision a fine sequence where know-it-all nerd kids, instead of hoeing weeds, are arguing with each other about what happened and why. Some kid has memorized a list of things that happened just before the birthdate of the oldest known individual who did not die. They argue about each and how it possibly could have resulted in what happened. Actually the kids working the fields and this discussion would be a fine way for the story to begin - the nerds obviously picking up an ongoing and longstanding argument. Dialogue is better than didactic. [Answer] Based on your other question it doesn't necessarily need to be a disease correct? This was simply a great answer you got to that question. What if it isn't a disease, but a hazardous substance everyone was exposed to 18 years ago which is having an effect 18 years later. Maybe an element from space entered the atmosphere, and was effectively recycled after a small amount of time on earth, but those who did come in contact with it were damaged in a way that eventually kill all of them in approximately 18 years? The children survive because they were not exposed to the hazardous material? [Answer] ### Parasitic cicada-wasp-aphids (This doesn't actually have to be as dramatic as infectious insects, unless you're into that kind of thing. It could be a tiny fluke or [symbion](https://en.wikipedia.org/wiki/Symbion) that happens to have a life cycle similar to a cross between a cicada, a wasp, and an aphid.) 19 years ago, a new parasite was either created or discovered. It may be a mutation from a parasite that infected another species or the creation of a mad scientist or weapon project gone wrong. In the adult phase (the original adults were either lab-grown or matured in their original host species), it is extremely infectious, but effectively harmless. It is capable of reproducing asexually through parthenogenesis, producing tiny adults that skip their larval phase and go straight to asexually-reproducing adults. It quickly spreads throughout the world, becoming a global pandemic. It then produces males, which mate inside their hosts. The males die and the females burrow into the brain (or any other vital organ of your choice), lay eggs, and die. All of the adults die off after reproducing. These eggs hatch into larvae. Like the 17-year cicada, the parasite has an extremely long larval phase. It is small enough to feed off of small amounts of blood without harming the victim. The larvae do not migrate, so any children born during this period are not infected. 18 years after the worldwide pandemic phase ended, the larvae mature. They then attempt to break out of their hosts, but due to a failure in their design are unable to break out of humans (unless you want this to be a cycle that recurs every 18 years). However, attempting to break out does kill the host. The only humans remaining are children born after the initial infection phase. [Answer] As I said in ym comment to [Feyre](https://worldbuilding.stackexchange.com/a/80445/34902)s answer, make them realize they are infected and develop a medicine that only works on children that are not through with puberty. That way the adults are sure to die, yet the cured children will survive. If you want less older children make it work better the younger the person that is cured. This might involve some handwaving though. Another alternative, make the cure only work on pregnant woman. So the woman gets the cure, the baby in the womb is immunized, the mother dies eventually. [Answer] A big thing here, is that a realistic and 100% idea will never mix. You cant have both in real life. That being said, if we want to get as close to 100% as possible, the best option is to figure out what the difference is between teenagers/children and adults that is not arbitrary like age. One idea, Almost by definition, is puberty and development. Until we are around 21 years old on average, we are still developing. It may be slower than when we were 13, but its there. There is a reason why the drinking age for alcohol in the USA is 21. The brain is still developing throughout all teen years, and even into their 20s for many people. So, if we tie this virus to the brain, with fully developed brains being helpless, we will kill almost all adults, but leave a few 20 year olds, as well as kill a a bunch of older teenagers. The hard part is what specifically it does, and how a brain that is not done developing could survive, but fully developed ones can not. This is where we get into unknowns. One solid choice is that an undeveloped brain is more 'elastic', and so we could say that those brains can work around the virus. People can live without large parts of their brain. We could say that this virus affects critical functions, and a developed brain cant work around them fast enough, killing the adult. A child's brain on the other hand, with its elasticity, could theoretically work around the defects fast enough that they don't die. From there, the virus has killed off everyone it can, and those left behind are immune, and so it dies out forever, or keeps spreading to new born's, but cant kill them and so is harmless. A realistic scenario here, the virus is rapidly spread over the course of a year by a malicious entity (perhaps fanatics who want to purge all humans). it takes 2-4 years to kill the person, but if your under the age of 16, you are likely to survive. After that, its harmless. You either die, or become immune to it, and no child under the age of 13 when infected will die from it, leaving the whole world dead or immune, with 99% of the population being under 18. [Answer] I'd say, kill some small percentage of the children, too, like 20%: Say any and all women that are pregnant when they are first exposed to the disease, pass it on to their fetus; but the immune system between the mother and the fetus is mediated by the placenta and other mechanisms (e.g. the bloodtype of the fetus can be different than that of its mother). So this filtering effect causes the fetus to "grow up" with the disease while its immune system is still "learning the ropes" (IRL immune systems must be trained by exposure; i.e. we "gain" immunity --- so if the fictional disease is one of the first things a new immune system ever sees, it *crushes* it), and because of that about 80% of the fetii exposed to the disease while in the womb just have immunity to the disease. The robustness of immune systems is not uniform, either; they vary from child to child, so for example some get sick more often, some less often. So in the story about 20% of children, born with the weakest immune systems, will spontaneously abort or die shortly after birth. Since all the children conceived **after** the initial exposure will have been exposed in the womb from the start; nearly all of them survive. Presuming the disease vector is persistent, then in the subsequent generations, a newly conceived fetus will have the benefit of two immune parents, and be even more likely to survive. > > Added: I don't wish to modify the above because it has already > received votes, but as per comment by @TheNate below; if you find my > biological explanation wanting; there is a simple bright line you can > exploit: 18 years ago, everybody under 18 'now' was still in the womb > or not yet conceived. That is the bright line. > > > I would add that for a short-lived pathogen, > being in the womb may have protected them from exposure or infection; > and that could apply **even if they were conceived by infected parents;** > such persons still develop from a single cell inside the womb, and could plausibly be protected. So if > the pathogen itself infects everybody but dies out in a matter of > months; you have a bright line: Everybody born after it dies out was > protected in the womb, and never gets infected. > > > [Answer] Some food additive got banned 18 years ago. It weakens the immune system and the common flu becomes deadly to those who had that supplement. [Answer] Dengue fever is tough, but a secondary exposure to a different strain of Dengue causes hemorrhagic fever (see the wikipedia page under Mechanism > Severe Disease). A disease that first swept the population (but was survivable) 18 years ago, followed 18 years later by a second wave of a slightly different strain, could cause hemorrhagic fever in people over 18 who had survived the first exposure. [Answer] Although I can't think of anything that would be 100% effective at the age of 18, perhaps a hormone-based solution might do the trick? The disease feeds/is stimulated by sex hormones such as estrogen and testosterone and produces a mildly toxic byproduct from the interaction. This could be balanced in such a fashion that once they become "adults", the concentration of the toxic byproduct kills them. The result would be a disease where no-one ever becomes a mature adult. The drawback would be that it is not precisely 18 years, since human development speed varies, and that people with hormone deficiencies could survive the disease. Nevertheless I hope this helps bring more ideas into the answer pool. [Answer] This answer will get a LOT of hate, given current events, but here goes: At age 18, absolutely everyone gets a vaccine against disease x; the vaccine is terribly flawed and exposes you to disease y, which for the vaccinated, is like airborne weaponised ebola. ]
[Question] [ The year is 2267 A.D. Humanity has colonized Prima Centuari system. A federal government is established; the population is expected to grow at an exponential rate to reach 1 billion by 2300 A.D. A self-destruct button is self explanatory: you punched the button to start the countdown sequence. When the number reaches zero... kaboom! The Emergency Off or EMO button is more forgiving. It simply cuts off the primary power supply and leaving the ship's circuits deadish! However, crew can then manually reset the button to allow current to flow through again. There is nothing lost but time. I am wondering why new non-military starship blueprints would include a self-destruct module and have the EMO button taken out? Note: in my story, self-destruct and EMO are mutually exclusive! No FTL. [Answer] ## Self destruction destroys stuff, which can be a good thing. * **Secrets must be kept**. Just shutting off or even "wiping" a hard drive can be reversed. Utter destruction of data and those who understand it will ensure all secrets are kept if the ship is about to be captured or scanned by the enemy. * **Clone missions must end**. In a setting where human clones are possible, there may be reason to destroy extra copies. For instance, you may upload yourself onto a body and board a one-way probe to explore an uncharted system. The mission needs your experience, but you don't actually want to be there. When you're done, you can effectively annihilate the clone so there aren't two of you. * **Sabotage or violence may occur**. While less of an engineering reason, ships can self-destruct for the sake of plot. If someone wants to kill everyone on board, this works. * **Sterility is law**. We [clean](https://en.wikipedia.org/wiki/Planetary_protection) and, if we have to, [intentionally destroy](http://www.universetoday.com/8884/galileo-plunges-into-jupiter/) spacecraft to avoid polluting habitable worlds. If there is some interstellar treaty in place to protect certain planets, perhaps blowing yourself up is the only way to adhere to the law. * **Torture is imminent**. [Cyanide pills](https://en.wikipedia.org/wiki/Suicide_pill) and other covert methods of suicide have been used historically by captured spies. While protecting information, as stated above, is one reason for destruction, the other could be potential unpleasantness awaiting. [Answer] Expanding on what Zxyrra said: * Imagine the ship meets something nasty and the best solution is not to come home again. *Here there be dragons,* and all that. Perhaps they meet a hostile, sentient species, or they contract an alien plague. Should the suicide be left to each individual crewmember, or is that something the command staff decides for all. * A non-FTL, interstellar craft is a deadly kinetic energy weapon. A self-destruct which literally vaporizes the craft (should be possible with the energy levels of interstellar flight), a near-c projectile becomes an expanding near-c cloud. This could be less of a hazard to systems in the way. [Answer] ## Different Reactor/Propulsion/Fusion Core Designs This is basically the difference between "fail-safe" and "fail-fail". If a "fail-safe" system malfunctions, it does so in a safe manner. A "fail-fail" system does not. So maybe the older ships used a propulsion or power generator method that had a "fail-safe" emergency shutdown mode. Then when a new generation of propulsion/powerplant is introduced, the same emergency shutdown mode is provided. In the lab and the prototypes, everything works correctly, but in field conditions/the production model, something seemingly inconsequential is different, and the new design does not shut down cleanly, turning "emergency off" into "self-destruct". [Answer] **You might not want them following you home** You never know what you might run into out in the deep of space. If you come across a new civilization that would pose an imminent threat to humanity, such as the xenomorphs from Alien, the Prime from Peter F. Hamilton's commonwealth, etc. then you'd be better off destroying the ship than risk someone trying to go home and bring trouble with them. Self preservation is a very strong instinct, and so having a way to override it is important. If the universe is a [dark forest](https://philosophy.stackexchange.com/questions/18127/dark-forest-postulate-used-to-explain-the-fermi-paradox) then anyone going out into it has a duty to humanity to have a way to ensure that trouble stays out there. [Answer] > > The Emergency Off or EMO button is more forgiving. It simply cuts off the primary power supply and leaving the ship's circuits deadish! However, crew can then manually reset the button to allow current to flow through again. There is nothing lost but time. > > > If the Crew can reset this button, then so can an attacker. If he can't figure it out himself, he can always capture fleeing crew members and "persuade" them to give him the information on how to reset the button. There are a few reasons to destroy a craft. The first and foremost reason is to protect secrets - both data contained within the data storages on the ship, as well as technological data. If you can get your hands on a brand new F-35 it would be awesome. It could be that up until know, humanity was either alone and they have found a new enemy, or humanity was united before and now there are factions. Self destruct was not neccessary because there was no enemy from which to hide data/technology. Now there is. Self-destructs become mandatory for all new ships, and old ones must be retrofitted within the next X months. Maybe it becomes *illegal* to completely shut off the ship because that way it would be too easy to board (automated defenses are now required, and they need to be powered). This means ships that become retrofitted with the self-destruct also get fitted with automated defensed, and a complete shutdown is not longer possible because power generation must stay on, as well as targeting systems, a rudimentary attitude control, and the automated defenses. Maybe the retrofiiting process takes longer then required, and some ships can avoid getting retrofitted for years. This would be ample time for a storyline with both types of ships to happen. [Answer] The ships were never designed with a self-destruct system, why would anyone do that? But after the first attack the recovery teams looking for survivors found \*censored for the wellbeing of readers\*, there were no survivors. It was obvious that a quick death was a far better option than being captured. The self destruct simply removes the safety controls from the drive and dumps fuel in, the countdown a matter of how long it would take to blow. --- This of course is highly dependent on what is happening in your universe. The choice to self-destruct is a question of what the other option is and if it's worse to be captured then self-destruct is viable. If it's simply a matter of not letting certain technologies get into the hands of the enemy, then it's going to be hard to get ordinary crew members or passengers to go along with it. [Answer] In Harry Harrison’s [The Daleth Effect](https://en.wikipedia.org/wiki/The_Daleth_Effect) the new spaceliner had a self-destruct and the flight crew had a habitat that did connect to the main passenget area. This was to protect the highly-propietary technology used in the drive. They would rather blow it up than allow it to be hijacked—and publicising this fact was intended to let would-be espionage agents know not to try. [Answer] **Reactor Design** It doesn't have to be a mistake. It can be a necessary part of something else that is a feature. If the basic recipe for nuclear fusion propulsion is to have a nuclear fusion bomb-like chain reaction and the only thing that normally prevents it from destroying the ship is an active containment system that "squeezes" the reaction so that it happens more gradually, turning off the control mechanism while the chain reaction is in progress will blow up the ship. But, you might have an manual override for the containment system, because sometimes engines experiencing multiple chain reactions of nuclear explosions need some repairs and the idea would be to do so normally, when the fuel for the fusion drive is exhausted, so that the containment system itself doesn't kill the repair crew. It needs to be manual because one of the things that can break is the sensor that says a reaction is still going when actually, the fuel is exhausted (which would otherwise be the fail safe to prevent a shutoff of the containment system when it could self-destruct). Indeed, that's one of the most fragile parts in the system (just like the warning indicators in my car). But, once you have a manual override, you have a manual override and it can be used at inappropriate times, turning an EMO into a self-destruct system. ]
[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/45666/edit). Closed 7 years ago. [Improve this question](/posts/45666/edit) When people consider a war between planets, they immediately think of throwing [big rocks](https://worldbuilding.stackexchange.com/questions/33627/how-would-the-inhabitants-of-one-planet-kill-the-inhabitants-of-the-other/33666#33666) at it. What my question is, when you know another planet is going to attack, what is the **first thing** that should be done ? Do you immediately start building a giant death star ? Do you ramp up your production of anti-matter ? Assume for this question, that people can travel at .9c but can only send **messages** instantly. We(Earth) are fighting a planet that is 1 light-month away, and that planet is really determined to destroy Earth (We don't know why). Also, everyone on Earth knows this and is working together (except for like 10% who protest and slow things down and 5% who help, but in a way that benefits themselves, which also slows things down). Earth and the enemy planet are both [Type 2 civilizations](https://en.wikipedia.org/wiki/Kardashev_scale#Type.C2.A0II_civilization_methods) .There is a world government, and then country governments. (For Earth) **Question**: What are the first things that should be done - * Political-wise : You have to act as if you can win this war, and start mobilising the scientists, but what do you tell ? * Military-wise : What weapons to create first ? * Defense-wise : How will you defend yourself ? What steps do you consider ? (Just answer these 3, and this is the first question in a series of questions) [Answer] Everyone is going to die. An observed reality of warfare is for offensive technology to ever outstrip defensive technology. One obvious example is guns-vs.-knights (guns are still effective centuries later). As your Kardashev level increases, the stakes increase exponentially (literally; it's an exponential scale). As a direct result, the only way to truly win a war in the far future is to either strike unilaterally, or to have a vastly superior tech level. --- However, your situation is balanced technologically, and both sides are in agreement that a state of war exists between them. So both sides kill each other. I'll unpack for you exactly why, also explicitly answering your questions: 1. Political: There is massive denialism abut the above facts, and nationalist (or *Earth-ist*, as the case may be) pride assures the people that they'll win. It isn't a problem to motivate people against existential threats so long as they're near-term. 2. Offense: Offensively, the answer is obvious; from as many sources as you can, you send out relativistic projectiles toward everything the enemy owns. Back them by laser bombardment. 3. Defense: Defensively it won't really matter. But you can try to shoot lasers at the projectiles that they *will* launch before they reach final speed (throwing off the intercept). If you're ambitious, you can try to move something like a planet in-between you. These actions are predictable by both sides, and both sides do them. Ultimately, though, a single relativistic cloud of sand trumps any laser defense system you could possibly build. You can counter any shielding by shooting from the sides (or just concentrating missile after missile on a single point, since it can't be reinforced). Since both sides are technologically equal, the only way to win is to strike unilaterally (or, equivalently, first). Given the delay involved in interstellar travel, there are no second chances. So, both sides must strike as aggressively and quickly and thoroughly as possible. Both sides run through these same conclusions and attack each other in every way they can possibly conceive, countering every defense they anticipate of their enemies. Since offense outstrips defense, every target is destroyed, and the war ends in a grim tie of mutual annihilation. [Answer] > > that people can travel at .9c > > > This is basically a [MAD](https://en.wikipedia.org/wiki/Mutual_assured_destruction) situation. If you can accelerate substantial mass to .9c, then that becomes a planet-shattering un-interceptable super weapons. And if both sides have the same level of technology and have some of those super weapons prepared, then if one side attempts to use it, the other will immediately use theirs. [Answer] Depends what you want to accomplish, how much destruction is acceptable, what your endgame is, and what technology you have at your disposal. If the goal is elimination without regard to civilian casualities (aka massive war crime) and long time consequences, then throwing rocks is a fine solution. It's crude but effective. There's little reason to engage in a costly war, or building expensive weapons when you can just put thrusters on a rock. At .9c you'd have trouble finding a more destructive and cost effective weapon than rocks. There are little defense against this besides prevent the other side from installing said thrusters on said rock, or hacking the Mainframe™ to take control of the rock's guidance systems to deflect it (if applicable). You would be justified to retaliate with the same kind of tactics and disregard for collateral damage the moment you detect them trying to launch rocks at you. Though, you know, if you can detect that there's a good chance it's already too late. Now what do you say? "These aliens want to destroy us, we'll show'em a good time, hooah!" I mean, if it's about survival, it's an easy sell. Humans like to survive. --- It's a different story if your goal is conquest and you don't want to kill everyone on the planet. Then you have a full scale war on your hands, and there are a variety of ways to go about it, which can end in a various degrees of disaster for both sides. [Answer] ### Build a gigantic network of observation satellites. Given sufficient time to prepare, anything that can be spotted can be stopped. A meteor lobbed at your planet can be intercepted with a meteor of your own, either deflecting it away from the planet or breaking it into small enough chunks that it will burn up in the atmosphere. A fleet of antimatter bombs can be met with a fleet of interceptors, with multiple redundant interceptors targeting each incoming missile. Once you see something, its trajectory will be relatively fixed, and you can deal with it. Instantaneous communication means that you can react as soon as you see something, but if you wait until you can see it from your planet, it's already going to be $\frac{9}{10}$ths of the way there. Your first order of operations will be to extend your detection range as far as possible. Any reasonable approach trajectories from the other planet will be your first target to observe, moving progressively further from your planet. Your ultimate goal will be to get your satellites in orbit around your *opponent's* planet, so you can see all of their launches in close to real time. Your second goal will be to stop them from doing the same. A successful attack on your enemy will be largely dependent on your being able to launch it undetected. If you can deny your opponent forward observation posts, the light from your launches won't get to them until just before your attack does, which will hopefully be too late. [Answer] Everyone has so far mentioned the use of "Fast Rocks" as an offensive weapon. If I were defending a planet from "Fast Rocks", I would do as follows, creating a set of defensive perimeters. The farthest away would be the distance related to defending from obvious, undisguised attacks. This distance would be set such that, no matter the direction of approach, I could bring my own "Fast Rocks" in to position and speed for intercept. This would likely be very far from my own planet, but not anywhere near the enemy planet. The second perimeter would be the distance away I could safely intercept an approaching object with a set of "Fast Rocks" already prepped and in position. This would be much closer to the planet. Finally, I would have an approach corridor to my planet. This approach corridor would be shaped much like an hourglass, with the thinnest point at or around half-way between the far perimeter and near perimeter. Objects of any type entering the thin "Checkpoint" must start to decelerate at a rate that will make sure they reach a "reasonable" speed by the inner perimeter. Any object that is deemed suspicious is told to decelerate to a stop by the second perimeter. If an object exits the approach or acts in a dangerous manner is assigned a "Fast Rock" for intercept from the stockpile near the approach. This plan should allow for the defense of the planet while allowing shipping to allow continue, maintaining the all-important industrial capacity of my civilization. This would allow for "Customs" to occur off-planet at the Checkpoint, and would be easy to adapt for peacetime use. In terms of offense, it depends on many factors. If I knew that I had a stronger industrial capacity and more access to rocks than my enemy, I would simply stockpile and set them up before shelling the planet until it has no more rocks of its own, having used all of them on intercept. Literal MS Paint Diagram [![enter image description here](https://i.stack.imgur.com/Jm6oT.png)](https://i.stack.imgur.com/Jm6oT.png) Edit: I know this is a fairly incomplete answer, but a lot of clarification would be required for further investigation. In addition, it is just an exploration of defense from large, weaponized meteors or ships as kinetic weapons. Edit 2: This is assuming that the civilizations have highly advanced scanning equipment. I am not worried about the detection side of things because in order for common interplanetary and interstellar travel, a ship would need to be able to be very sure that there is nothing in it's path, both when moving at normal speeds and near the speed of light. The energy imparted by even the smallest of objects moving at 0.9c is truly impressive. In order for advanced trade between planets, there would need to be very sophisticated scanning equipment. ]