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[Question] [ **This question already has answers here**: [Sensors for a clockwork/fluidic robot?](/questions/169026/sensors-for-a-clockwork-fluidic-robot) (3 answers) Closed 3 years ago. Ignoring the constraints of mechanical computation, what sensory modes are even available to such a robot? Even in the 21st century artificial odor detection is rather primitive, and we have over a half of a century of solid state electronics under our belt. So I'm assuming "smell" is right out. Hearing also seems problematic as well... while maybe microphones are possible, I suspect that without electronic amplification of some sort, getting a useful signal out of them will be impossible. Is that so? But the real question, I suppose is this: can the clockwork robot see? It doesn't have to be color vision, it doesn't even have to be proper black-and-white vision. Can it see at all? I'm inclined to guess that there might be some clever mechanism that I can't think of that would allow it. Photography existed long before the advent of even the simplest electronic devices... but used chemical media to fix images to suitably prepared surfaces. I can't figure out a way to turn that into a mechanism where a particular rasterized pixel turns a gear (let alone able to reset and do it again a fraction of a second later). Could a clockwork robot even crudely sense light, the way a cavefish might? [Answer] **Sound** This one is easy, you know how a [phonographe](https://www.google.com/search?q=phonographe&rlz=1C1NHXL_enGB711GB711&oq=phongraph&aqs=chrome.1.69i57j0l7.11942j0j8&sourceid=chrome&ie=UTF-8) works, well there you go, all mechanical with no electronic parts, the movement of the stylus for reading from the cylinder & (more pertinently for your purpose) for writing to it is purely mechanical. *And if it can hear then with triangulation of two or more ear trumpets we 'might' plausibly claim it can 'see' by constructing a 3D image by echolocation of solid objects in its surroundings.* **Temperature** Thermostatic [Bimetal Coil spring](https://en.wikipedia.org/wiki/Bimetallic_strip) thermometer, again completely mechanical with no electricity. [![enter image description here](https://i.stack.imgur.com/jb3Fz.png)](https://i.stack.imgur.com/jb3Fz.png) *I'm not sure why you might want it, but if you want it to have a temperature sensor, you can have it.* **Pressure** A liquid filled [pressure gauge](https://en.wikipedia.org/wiki/Pressure_measurement) can be used to measure external air pressure (or else water pressure if submerged), also entirely mechanical & easily interfaced with clockwork. Of course rather than a tyre pressure gauge I imagine it more along the lines of a combination. [Pressure altimeter](https://en.wikipedia.org/wiki/Altimeter) [Barometer](https://en.wikipedia.org/wiki/Barometer) [Bathometer](https://en.wikipedia.org/wiki/Bathometer) [![enter image description here](https://i.stack.imgur.com/8mmrg.png)](https://i.stack.imgur.com/8mmrg.png) *Not sure why you'd want that one either but there it is.* **Gravity** A finely calibrated [spring scale](https://en.wikipedia.org/wiki/Spring_scale) with a known weight suspended from it could be used to measure locale gravity, only while the robot is at rest & not moving of course. A possible use for temperature sensor here, for accurate readings you may need to adjust for the effect of locale temperature on the spring. [![enter image description here](https://i.stack.imgur.com/jzOUm.png)](https://i.stack.imgur.com/jzOUm.png) *Why you'd want this sensor escapes me, but I thought of it so here it is anyway* **Motion (Up / Down & 'Attitude')** A mechanical [gyroscope](https://en.wikipedia.org/wiki/Gyroscope) set up that trips mechanical switches in it's casing might be used to tell it which way is up etc // Or a series of pendulums set at different angles // Or you can model a sensor on the inner ear, a hollow sphere with many small button switches covering the entire surface of the interior & a ball inside heavy enough to depress any switch it rests on. You might use all three. *You might want motion sensors in all its extremities as well as the torso to help give it a sense of what it's 'body' is doing.* *Unexpected motion will cause these to jiggle & bounce so these might double as shock sensors.* *Speaking of which.* **Shock** There's a whole range of early purely mechanical shock & impact sensors you might use including those used for early bombs, landmines & [seismographs](https://en.wikipedia.org/wiki/Seismometer). **Time** It's a clockwork robot right, so that's probably all I need to say for this one. **North** A strongly magnetized compass needle, strong enough it can push past & trip small switches? *Large quantities of ferrous metals can distort a compass reading, so if you want this sensor you're robot shouldn't be made of iron or steel, nautical compasses had brass housings, you can use that.* **Touch** An easy one, button switches, spring loaded ones for measuring the force of it's grip, from your question you already have this worked out though. **Sight** Early 1840's [fax](https://en.wikipedia.org/wiki/Fax) & [mechanical television](https://en.wikipedia.org/wiki/Mechanical_television) technology look promising but both need electricity. There are [photomechanical materials](https://scitechdaily.com/tiny-micromotor-is-powered-directly-with-light/) that might be of use but most of them are perhaps a bit esoteric or advanced for a steampunk clockwork robot. Howsoever, if chemicals are acceptable to you there is early photography, [Heliography](https://en.wikipedia.org/wiki/Heliography), the plates are acid etched & then used to relief print the image, so the plates themselves might be 'read' with a fine needle in much the same way as a phonographe, it's going to have a limited supply of 'sight' & won't be able to use that on the go but it could have still shots of its surroundings. Exposure time required for each plate is probably in the range of several minutes to a few hours (faster if the light's stronger) so you're not going to get a particularly fast frame rate this way. *But it would be a lot easier if we can use basic [selenium](https://en.wikipedia.org/wiki/Selenium) photocells.* [Answer] About the only way I can see sight working without some sort of electrical signal is to detect heating caused by focused light. You do have a few options for detecting the heating - I'd imagine the most responsive would be heating gas in a sealed container and mechanically measuring the pressure it exerts. The timescale would probably not be great, but it would depend on the amount of light. If you're willing to go for some sort of giant-squid eyeball you might do something A square meter area in typical daylight conditions has several hundred watts of power, so if you directed a fair chunk of that (say 100 watts) into a one-liter gas chamber (contains roughly a gram of air) you'd double its absolute temperature in a couple of seconds (it takes about a joule of energy to heat a gram of air by one degree). This would provide one extra atmosphere of pressure - a square pressure pad 10cm on a side would measure 1000 newtons of force (enough to lift a grown man!) Since I highly doubt your machinery would need anywhere near that to detect something (one newton is probably plenty) you could detect light with that in a few milliseconds time rather than waiting a few seconds - probably as fast as your gears can react, giving real time (one pixel) vision The problem comes when you start scaling this down. We talked about one square meter of light, but even the aforementioned giant squid has an eye with a pupil area more like 0.01 square meters, meaning even the ideal situation above would take a fair chunk of a second to register. Worse, indoor areas are nowhere near as brightly lit as that, with a few watts per square meter being considered very well lit, as opposed to the hundreds you'd get outdoors even on a cloudy day. That probably requires more time to register than would be useful. Multi-pixel, 2D vision? That'll be really tricky. With even a pixel size of 10cm being very borderline, gathering a useful number of them would require an absolute leviathan of a clockwork beast. (If you are building an absolute leviathan, problem solved!) About the only way I see you being able to scale these pixels down to a more usable size is if your creature lived very slowly, collecting light not by having a large area, but by waiting a long time to gather it. TL,DR: Cave fish vision is doable if you are willing to pick two of large eyes, slow response time and restriction to broad daylight. Any remotely detailed vision is probably not doable by purely clockpunk means unless the creature is very large and lives in slow motion. All this assumes we stay purely mechanical - you could go the route of having actual living creatures in the eye that do something in response to light, along the lines of the Terry Pratchett cameras which have an imp inside them drawing very fast - but I don't know nearly enough about animal behaviour to comment on that one! [Answer] A bi-metal mechanical switch reacts to heat. So you could focus light with a lens and heat the switch that way. It would be very crude, and easily disturbed by changes in ambient temperature, but in theory it should work. [Answer] Photossensitive resins have been known for a long while. So have lenses. A couple moving lens and a round chamber can simulate an eye. A honeycomb structure at the back of the eye simulates a retina. The change of pressure caused by the resin shrinking/expanding or softening/hardwning transmits a signal to a series of springs, one per pixel. There you have it, now you can process it with perforated cards for facial recognition. [Answer] What you can try to implement is something purely mechanical: * the light hits one of two springs * the increased temperature on the light hit spring causes the two springs to change configuration * the configuration change triggers some mechanism to start the signal "I am detecting light" It's a really crude mechanism, but I think it's the best you can get with something solely mechanical. ]
[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 3 years ago. [Improve this question](/posts/168036/edit) In a very near-future (as in, assume no spectacular technological advances or changes to society) post-apocalyptic situation, would a group of survivors scavenging a store after all of the fresh produce has rotted away (and the frozen produce has joined it due to lack of power) be able to use the kernels of corn for popping to grow new corn or is something done to it in processing it for use in making popcorn that renders it no longer viable as a seed. (Or, for that matter, is popping corn one of those hybrid strains that do not produce viable seeds in the first place. It's okay if seeds don't produce popping corn, as long as they produce *some* kind of corn.) Bonus: If regular popping corn, the kind intended to be used in popcorn poppers, pots on the stove, etc., is still viable, can the same be said for the kernels inside unused microwave popcorn bags? (If, for example, the store the survivors were searching was just a convenience store, and not a supermarket, so their selection was considerably more limited.) Note: this question is not asking if popping corn is a viable source of nutrition, as that deserves to be its own question. (After all, at the very least, it should provide the survivors with a source of carbs and/or animal feed, so long as they can actually grow it in the first place.) [Answer] It will depend on the variety of popcorn and the prep method. Some varieties will by hybrid that won't breed true. Depending on the specifics of that, you could get a sad little bit of corn in the next generation that has about 3 kernels on each cob. It may be that you can plant several generations and get something useful out of this. Or it may be that it won't produce a second or third generation. Other varieties will be less hybridized and will breed true or nearly so. I have not tried this with popping corn. But I have tried it with sweet corn. Some varieties will just not germinate. Some will germinate and produce truly sad looking corn in the first generation. This is why seed companies are able to stay in business. Some types of popcorn will have chemicals on them that prevent germination. These are the chemicals that allow the kernels to stay in those pop-in-bag things for a year or two. If you get the kind that just comes as a jar of kernels with no butter or other stuff on them, you will have better luck. [Answer] The reason why certain variety of corns are used for popping is in the specific properties of the seed (you need a proper shell permeability and a proper humidity of the core to pop it). All the rest is perfectly viable for general purposes nutrition. You might have additional risks due to the limited genetic variety, but that's applicable with any industrial seed in a non intensive agriculture scenario. As a kid I planted some unpopped pop corns in my garden, and they gave regular corn in due time. ]
[Question] [ Let's assume some things: * The ground under the object is flat land. * The object always remains in the same position. * The object is clearly visible from the ground. * It is a high priority for the people to reach the object. The method used can be anything, such as building a tower or just piling up a huge mound. How high would you have to place this object to make it credible that people have never reached it in hundreds of years? Bonus question: How high does it have to float to avoid being hit by flying objects thrown by trebuchets, ballistas or any machine specifically built for hitting the object? [Answer] There is a well-researched limit on how high a tower (Tower of Babel) can be built without a metal frame (steel or bronze): stone, baked brick, or fully vitrified brick all have their limits, based on the strength of the material. I recall this figure as being about 4000 feet with the strongest of these (fully vitrified brick), using a profile somewhat like a very squat-looking Eiffel Tower (slope increasing with height). The volume of these bricks required is problematic, given that the base of a tower that high would be significantly more than a mile across (I don't recall the exact figure), as is the very technology of making fully vitrified brick, which (in our world) wasn't invented until the 19th century -- but that's your figure. Without the mid-20th century technology of steel frame building, it's *impossible* to build taller than approximately 4000 feet (1200+ meters) with any real world material. No trebuchet ever built threw as high as this -- they were built for lobbing heavy objects distances of a fraction of a mile, and for maximum range (within distances where the Earth may be treated as flat), the highest point in the trajectory is just half the range. Even for a torsion catapult of the spear-throwing sort, 4000 feet is awfully high, though I won't claim it would be impossible to reach. Gunpowder weapons, using a large powder charge to launch a lightweight ball, can easily reach this altitude, so you may want to place a limit of pre-gunpowder technology (practical guns that could do this date to the early 15th century). [Answer] There is no definite limit. Given sufficient time a medieval civilization could build a very tall artificial mountain out of stone blocks. The height depends on how determined the people are to get to this floating object, how big and industrious the nation is that is trying to reach it and most importantly how long they have to do it. Years, decades, centuries, millennia or more? As the time span increases the height potentially reached increases although the plausibility of the scenario decreases. As a guestimate I suggest that decades are a reasonable best estimate. In that case 1000m would be inaccessible even if they were to build a pyramid, put a tower on top and a ballista on top of that. [Answer] "The object always remains in the same position." + "(people have never reached it in) **hundreds of years**" Assuming the object is placed within the atmosphere, these two constraints sort of make the height irrelevant. Any technology that can manufacture an object capable of staying afloat, undamaged, without moving relative to the earth (ie unaffected by wind currents, storms, potentially even more extreme events like volcanic eruptions etc) for hundreds of years can probably make the same object completely untouchable by any means a medieval-level civilization could possess or develop. Assuming the object can be in space, the cheap answer is to put it in geostationary orbit. It would have to be pretty damn big to remain "clearly visible from the ground", but if you accept that it can only be visible, say, during the nighttime, it is feasible to keep such an object there for many hundreds of years, and a medieval-level civilization would have no way to reach it. Another cheap answer is holographic projection. Bury a projection method in a nearby mountain and just have it project an image. That way you can ensure that no matter what, it cannot be reached. Bonus points if you program the projector to always shift the image slightly upwards when it detects some mass closing in. But if you don't like any of the above: a medieval civilization can make a hot air balloon. The highest a hot air balloon has reached is about 21 km, comfortably over twice as high as Mount Everest. If you were to get creative and mount a ballista (should be better than a trebuchet if you want height, when pointed straight up) on some kind of hot-air-balloon-grid (hey, you said reaching the damn thing is a priority, right?), you might edge in another half kilometer or so. To make it safe I'd say that somewhere in the area of 25 km would make it pretty safe from the hands of your medieval civ. [Answer] It seems to me that if the object floats a few kilometers or miles high it will be out of reach of any method ancient or medieval society would have. They could try building a tower of Babel or ladder or ramp up to the object or shooting catapult bolts or cannon balls up once they discover gunpowder in the late middle ages. But I doubt that they could reach kilometers or miles high. Here are some links to questions about building tall structures: [Tallest building possible by the Roman Empire](https://worldbuilding.stackexchange.com/questions/77984/tallest-building-possible-by-the-roman-empire/78325#78325)[1](https://worldbuilding.stackexchange.com/questions/77984/tallest-building-possible-by-the-roman-empire/78325#78325) [Could a supertall building have been built in the 18th century?](https://worldbuilding.stackexchange.com/questions/102573/could-a-supertall-building-have-been-built-in-the-18th-century/102640#102640)[2](https://worldbuilding.stackexchange.com/questions/102573/could-a-supertall-building-have-been-built-in-the-18th-century/102640#102640) [Practical height of towers without elevators](https://worldbuilding.stackexchange.com/questions/127314/practical-height-of-towers-without-elevators/127412#127412)[3](https://worldbuilding.stackexchange.com/questions/127314/practical-height-of-towers-without-elevators/127412#127412) But possibly there is a relatively narrow gorge thousands of feet deep. And the object might float thousands of feet above the river at the center of the gorge, and about level with the top of the gorge thousands of feet away to the side. In that case humans might try to build a structure on top of the wall of the gorge hundreds or thousands of feet tall, and try out out catapults, trebuchets, gunpowder rockets and cannons in other places to try increasing their range. And when the humans finally have weapons with sufficient range they might take them up to the top of their tower that`is hundreds or thousands of feet tall and is far enough above the object, and try shooting at the object after calculating trajectories that should intercept the object. Or the humans might try filling up the gorge and raising its level. If the object doesn't rise higher with each rise in the level of the the gorge, the humans might hope that eventually, after centuries or millennia, they might be able to raise the ground level high enough to built a tower on top to reach the object. [Answer] So answering your question, I think, a trebuchet would be the highest firing weapon. The largest one at Warwick castle throws a stone 300m, so let's assume a perfect arc, 150m up. (<https://en.wikipedia.org/wiki/Trebuchet>) The highest medieval tower was Chateau de Coucy donjon, which was 55m high (<https://www.guinnessworldrecords.com/world-records/512991-tallest-castle-tower-%E2%80%93-ever/>) The Great Pyramid of Cholula was 450m high (<https://en.wikipedia.org/wiki/Great_Pyramid_of_Cholula>) The largest man made mountain is Sophienhöhe, which is 301.8 m. (I'm assuming it would be technically feasible to build this in any era) (<https://en.wikipedia.org> /wiki/Sophienh%C3%B6he) So 150 + 55 + 450 + 301.8 = 956.8m Round it up to 1km. As others have said though, eventually, they'd probably find a way to get up there, especially if annoyed enough... ]
[Question] [ Are there specific writing ways to differentiate from the two (eusocial vs. hivemind)? I would like to start writing more notes and lore upon something I've been working with, but it does seem hard to not give each creature a specific individual personality and/or mindset. If it helps, here's a few short notes upon what I'm trying to deal with: A giant collective, the Contagion, which spawns from a elder deity as a biological reset onto a system if a species' empire becomes too great or too cocky. The Contagion sends messages among itself similar to fungi and plants sending warnings signals through stimulus, using pheromones like animals, and telepathy among the more intelligent variants. They are headed by a single individual called a Herald, who also receives order from the higher deity. (hope the tags are okay!) [Answer] The different bodies of a hivemind are constantly connected - since it's supposed to be ONE mind controlling all these bodies. An eusocial species has members that work together, but think (or act on instinct) on their own. [Answer] **Euscocial organisms** follows these rules three: * Reproductive division of labor (with or without sterile castes), in other word, specialized groups of the species are responsible for one task, usually to the exclusion of all others. For instance worker castes can't give reproduce (generally), or the reproducing caste can't do work like burrowing or building, * Overlapping generations, a colony can contain a mother and her offspring at the same time, and * Cooperative care of young, in other words, everyone pitches in to help the kids. Also, final point, eusocial species are always *beyond the point of no return*, they have no mechanism to return to the pre-eusocial state. **Hivemind** A quick Google search told me hivemind includes ant colonies, but can also refer to the collective consciousnesses of groups of humans, swarm intelligences (either the computer variant or the biological one), and a few others like the Mind Flayer from Stranger Things. This is non-helpful, but it told me that hivemind is just a loose word that people like using and has no rigorous definition. So, to summarize, eusocial organisms are real, hive mind is a jargon word which can means many things and has no rigorous definition. Thus, if it meets the rules three and is past the point of no return, it is eusocial, otherwise in can be labeled hivemind. [Answer] Well, the first way to distinguish them is that a hive mind is a mind. So anything mindless is clearly not a hive mind. For example, ants are eusocial insects, but as far as we know, have no mind, whether hive or other. Let's keep with the ants and imagine an advanced ant species that evolves a mind. This can happen in two ways: On one hand, every ant by itself might develop a mind. Then this would not be a hive mind; those insects would be eusocial organisms with an individual mind. Each insect would experience itself as an individual entity. If you hurt an ant, only that ant would feel the pain. An eusocial species with individual minds would likely form something like a fascist society: There are individuals, but they only matter as part of the collective. On the other hand, one could imagine that the ant colony as a whole would develop a mind, just as our body as a whole developed a mind, not the cells individually. In that case, the ant colony would be the person, it might not even be aware of the individual ants, and if it is, it would consider the ants just as part of its body. Unlike our body, its body would not be connected, but the colony would still consider the ant collective as a whole as its body, just like we don't consider our limbs or our eyes as separate beings. This is a hive mind: A single mind that spans the whole colony, rather than being an individual property of single ants. Note that with a pure hive mind colony, the ant would not have a mind on its own, just as our neurons have no mind on their own. Of course there might be a continuum between the extremes, just like there's a continuum on the social behaviour of animals. One might e.g. think of a sort of hive mind that can split into individual minds and reunite. Or one might think of individual minds with telepathic contact that goes beyond mere communication, so that they may have literally shared thoughts. Or there might be both a hive mind and individual minds which interact with each other. [Answer] I'm going to be Very Basic with what I'm saying, but I believe "hivemind" is just a spiffier way of saying "eusocial". Ants, bees, wasps, termites—they're all eusocial. The word "hivemind" is literally a compounding of "hive" and "mind" in order to refer to the phenomenon observable in these insects' colonies (the highest level of organization of sociality) with a word whose meaning is easier to deduct for us laymen. Comparatively, you need to know a bit about linguistics to know what "eusocial" means at a first read. "Eu" is a very popular Greek suffix that you can find in plenty of words (e.g.: euthanasia, eugenics, euphemism). It means "good". So with "eusocial", we're basically saying, "Hey, these little bugs got it all figured out, socially speaking." Of course, with "hivemind" cropping up in fantasy and science-fiction far more often than "eusocial", it has become a term associated with psionics and telepathy. Then again, we still don't understand how ants and bees and all those wonderful little colony-living bugs really manage to communicate so flawlessly, so eusociality in its own right is a bit of an esoteric concept! I would suggest you don't angst over whatever difference there may be between these words. For all intents and purposes, they're synonyms. ]
[Question] [ Silicon carbide is a ceramic often used in vehicle and body armor, but **could a living creature produce and use it the same way?** Assume the creature was genetically engineered. [Answer] **Plants make glass** Stinging nettle, ocean sponges and other plants produce glass. Nettles make their needles from it and sponges make their skeleton. These glasses made by plants are called "phytoliths", from the Greek "phytos", a "plant", and "lith", a "stone". See [Plants make glass](https://www.abc.net.au/science/articles/2001/02/23/246895.htm) If silicon is already being used in lifeforms, the carbon and hydrogen is also already there so silicon carbide isn't out of the question. [Answer] This [Nature](https://www.nature.com/articles/s41598-017-10587-5) article reports on electrochemcially producing silicon carbide in molten salt at 900°C. That's still pretty hot for the typical biological life form. Still, if the life form had an internal crucible made of silicon carbide, it is vaguely conceivable it could support a solution at 900°C. This [article](https://www.osti.gov/servlets/purl/1331380) from the U.S. Department of Energy Office of Scientific and Technical Information reports on room temperature electrochemical synthesis of a variety of carbide molecules, including SiC. So just possibly an organism with a huge amount of available electrical energy, and some truly exotic chemistry, might be able to produce SiC. The exotic chemistry itself might be weaponized. Maybe it starts with little nano-fibers that are glued together with more mundane forms of connective tissue. Then it gradually evolves to make larger and thicker plates. Possibly it can form claws out of the stuff. Possibly competition from similarly equipped creatures is what drives the improvements. Must have harder and stronger armor than George-across-the-forest or he gets all the girls. One part of an organism that often contains some electrical energy is the nervous system. So, in effect, the critter might be able to make SiC armor by thinking about it *really hard*. [Answer] **Intelligence and Knowledge are Weapons.** > > Silicon carbide is a ceramic often used in vehicle and body armor, but could a living creature produce and use it the same way? > > > Yes. They're called "hu-mans". They may not be very attractive, but they're smart. What they lack in beautifully colored fur or feathers, they make up for by wearing sacks and painting themselves different colors. :-) The fastest evolutionary path to developing sophisticated personal protection *is* intelligence. Nature will naturally tend to develop carbon-centered chemistry because it's what you're made of and it's relatively easy to work with. Everywhere in the universe carbon is going to be more abundant than silicon. To evolve armor like that would take millions of years. Once you have intelligence (at a human social level) you can create more and more complex armor and out pace evolution by a factor of millions of times faster. That's the reason humans have stomped all over everything larger than a microbe ( still working on defeating the microbes :-) ). It's no competition : you want well armored creatures, then you want smart tool making creatures that develop chemistry and alloys and ceramics and composite materials. > > Assume the creature was genetically engineered. > > > Even more advantage in making them smart and flexible toolmakers. If you want them to start out able to make such materials (or something similar) maybe you "hard-wire" the required skills and knowledge into them. At the very least you make them fast learners, concentrating your genetic engineering skills into giving them rapid comprehension and something like [eidetic memory](https://en.wikipedia.org/wiki/Eidetic_memory). Let's say one faction engineering a silicon carbide growing creature. Well how long will it take the flexible intelligent toolmakers to figure out how to defeat that ? Engineer something with better armor, the smart tool makers will defeat that too. I'll go with brains over brawn, thanks. :-) ]
[Question] [ In my story I have a strain of virus capable of stealing parts of or changing its hosts DNA, so it could copy the abilities in nature for its next host of choice by taking the genes which control the creation of cells for organs or processes such as an electric eels ability to generate electric fields or photosynthesis etc. At some point I need the virus to become sentient and conscious, either it becomes conscious after infecting the neurons of its choice host or it is some outside conscious colony of viruses (maybe in host bacteria if that helps) which is in control and can communicate with the viruses in the host controlling the host from a far. The viruses would work their way up to humans from more basic just running on instincts creatures to slightly smarter then finally to humans so hopefully the depth of our thought process won't be too much to handle. As my knowledge of science is limited it would be a great help for any known processes that could theoretically allow viruses first achieving consciousness from living in the mind and bodies of creatures taking control of them or by taking their DNA to some sort of colony where all the information is stored in a hive-like mass of viruses whose shared information gains consciousness? [Answer] Our consciousness is dependent on the communications between our neurons. Reasoning from that, you need your viruses to communicate. Since there isn't a fast channel available in reality, maybe you can invent one. It's very far fetched to imagine an artificial neuron network (ANN) or natural neuron network (NNN) forming in that higher dimension space, but that is why is it called speculative fiction. The virus might use Planck scale bosons or fermion strings vibrating in 2d to communicate between different virus bodies. The degree of a couple of vibrations between the different 2d entities and all the 3d virus bodies would provide an equivalent of the synaptic potential of a NNN or weighting of a trained path in an ANN actually a projection of a 4d or higher thing to into our 3d world, and the communication happens in the higher dimensions. With enough neuron equivalents and interconnects then one could propose intelligence as an emergent property. And given the time scale of Planck scale entities, they could conceptually evolve very quickly from intelligence to consciousness to a virus equivalent of self-awareness then sapience and whatever might come after that. [Answer] Viruses cannot achieve consciousness as we know it because they do not communicate among themselves. In the briefest terms, a virus is a piece of dna inside a microscopic capsule. The capsule has protheins that allow the viral DNA to enter cells and hijack their prothein producing mechanisms, but that's it. Therefore a virus can only be as intelligent as DNA is. But despite our neurons developing according to our DNA, our DNA in and by itself is not intelligent and does not communicate, much less from afar. Even if it did, the smallest of our chromosomes is orders of magnitude larger and more complex than a viral strand of DNA. Some viruses may seem at a glance to be able to control the host - such as the rabies virus. Turns out the aggressive behavior the virus causes on animals is a random trait that was favored by evolution, because it leads to spreading by biting. The virus does not control the host, and in fact the neural tissue of the host is, well, destroyed in the course of the infection. --- Don't give up on your storytelling, though. You can still write the story you want, with more or less realism. For a small level of realism, just write it without trying to be scientific about it. Take a page from Marvel Comics. In real life gamma ray exposure kills you. In comics you become the Hulk. If I remember well at least one writer in Marvel had it that all humans naturally have superpowers, but those are kept in check by intelligent bacteria, and all mutants with superpowers are people who are resistant to that bacteria. For a higher level of realism, forget about viruses and use fungi. Read about [cordyceps](https://en.wikipedia.org/wiki/Cordyceps). It might freak you out a little bit. For decades we thought this beast infected neural tissue, but just a few months ago scientists found out cordyceps can only control muscle tissue. It physically fights the insects' brains for control of their bodies! And fungi are known to communicate among themselves. Another finding about cordyceps is that every infected individual is infected by a colony, and the colony coordinates the signals it sends to the muscles. [Answer] There's an issue with the question. You assume consciousness is a biology defined term. It's not. It is a philosophy term. Thinking of it biologically is what's giving you the trouble. ## Let's talk biology first Viruses infecting brains is not common, but it's certainly not rare. Viruses mutating quickly is what they're known for. Viruses hopping species barriers is not rare either, but there's major limitations if you don't include dormancy in a carrier species (like mosquitoes). All these can be hand waved away in your story, as they're close enough to reality. Where you're hung up is on the evolution. Evolving and mutating viruses can certainly take DNA from hosts and incorporate it into itself, but such gene stealing is only propagated to the rest of the viruses via reproduction¹. The successful viruses would be the ones that reproduce the best. By definition, evolution favors replicators, not borrowers or hoarders (or whatever you envision the virus doing). Your virus needs a reason to attain and keep any genes it steals along the way. That's how evolution works and without that, science minded readers will notice. Most will probably forgive you if you mostly hand-wave it away, but brief explanations on how and why some traits were preserved would be enough. ## Now let's talk philosophy Consciousness is hard to define. There's varying opinions, including those that label it a construct only (which gets meta when you point out that it's because of consciousness that you can even discuss consciousness). Among biologists staying in their lane, they often just label it as a complex behavioral trait that is partially exhibited in lesser animals (like chimps), and like always, contributed to successful reproduction. Getting philosophers to answer why consciousness exists is like pulling teeth. Most will answer with rhetorical questions like: why do we love, why are we here, and who am I. It's a thing to ponder, not a question to answer. You have to ask yourself what consciousness means for you and your story. Does the virus comprehend itself? Does it understand how it affects its environment? Does it realize the limited nature of the resources that feed it? Does it have desires beyond its overt needs? Does it talk? Does it fear death? Does it believe in God? Once you figure this out, you can proceed. There's a fungus that drastically changes the behavior of ants by infecting the brain², but that's a far cry from consciousness. Further, the fungus within any given ant doesn't communicate with the fungus in another ant. That's collective consciousness, which is an order higher than individual consciousness, and doesn't exist anywhere, so far as we know. But your readers can probably forgive this quickly to, because it's a common trope. The closest we have in real life is colony and hive species. Ants and bees act with a peculiar single mind. It's quite fascinating, but requires proximity. All their communication seems to be chemical/behavior triggers. Ants aren't conscious and neither is their colony. If you want a collectively conscious virus in the brains of many people, you have to explain how they communicate. If each brain gets a unique consciousness, you don't have to explain anything. --- 1. I'm pretty sure viruses do this already, and I'm certain bacteria do with each other, though gene sharing might be a better term. The term gene stealer reminded me of the Tyranids from Warhammer 40K. This alien-bug species conquers worlds then dissolves all biomass to consume it and to incorporate the DNA into itself. You might find inspiration there. 2. Check out [Ophiocordyceps unilateralis](https://en.m.wikipedia.org/wiki/Ophiocordyceps_unilateralis) for some real life scifi. Nature can inspire your stories more than you typically expect. [Answer] My first answer on this site, here goes... I used to dabble in microbiology, and at first I dismissed your question as simply impossible. However it kept me thinking, and I came up with a chain of events. 1. Viruses 101 We have to remember that viruses are tiny and very very simple. They each have their tiny bit of genetic code, a capsule of some type and a few enzymes. They don't have a metabolism of their own, they are just a vessel for a few genes basically relying on cheer number and luck to spread. It is debated if they even are "alive". They rely entirely on their hosts to execute their only function: reproduction. This task usually overwhelms their host cells, who die performing it. Each virus strain has at most a few viable host cells. 2. Evolution 101 For any new ability for our virus to develop we need random mutations that make it better at competing against other organisms taking the same living space. A mutation occurs in a single virus, and is passed on to its offspring. Some viruses can pass segments of their genome to other viruses when they come to direct contact with them. Reproduction is the only "goal" of lower lifeforms, before our virus develops a conscience, it is simply implausible for it to survive with a trait that is a burden. Humans can make choices that hinder their ability to reproduce, but viruses whose ability to reproduce is hindered are snuffed out by more virulent ones. 3. Viral mass For a hive mass of viruses to develop, the viruses would need special hosts that can sustain them for a long period of time. The viral genes that turn their hosts into virus factories would need to have some sequence to slow the process down, as to not take over the whole of the cells metabolic capacity and burst them, as is the usual MO of viruses. Slowing down reproduction is not a strong card in natural selection, but if keeping host cells alive would guarantee them building new viruses for a longer period of time, the virus strain could in theory survive. Now we have a special host capable of sustaining our virus (=doing everything for it) on its way to greatness. 4. Communication As previous answers have pointed out, communication between neurons is the base of our human consciousness. For your viruses to develop intelligence, they need a rudimentary means of communication between units. Depending on the sustaining host, I think it can take different forms. For example, different cells of the immune system communicate with chemical signals secreted or on their surface, plant cells are directly connected to each other and of course neurons use a combination of electricity caused by ion shifts and chemicals. Search for other examples from nature to find one that suits your need. For communication to develop to our strain we of course need these random mutations to give it an edge over competitors. Maybe the capability to communicate helps the host cell evade danger? Again examples from nature can be drawn. 5. Hive mass We have viruses that have enduring hosts that can communicate. Now they need a reason to aggregate and form large masses. The human brain has up to 100 trillion synapses. This goes beyond my expertise, but biologically I don't see a reason why a mass of units of a similar number of connections couldn't theoretically form a single conscience. Now I imagine this sapient hive as a mass of undifferentiated cells, containing only billions upon billions of units of the chosen host cell including our viral genome. The size needed depends on the means of communication, even more connections than in the human brain might be needed. You also might need to take into account the being's size vs communication speed between units, which can result in much slower thinking compared to humans (this can bring new sides to your story). The being cannot reproduce itself as a whole, but is immortal. Physically the mass cannot reside inside another being, since the lifespan would be too short. It should be somewhere where it can constantly find new hosts to aggregate to the existing mass to replace dying host cells or to grow. A body of water comes to my mind. 6. Is it still a virus? The being reproduces its units by spreading vessels containing genetic code that take over host cells aka by spreading viruses. The genes used to communicate between units and aggregate to the existing mass would have to be contained in these viruses. The host cells do all the metabolic work but without the viral genome, they wouldn't be a part of this hive-being. The viral genome must be quite big at this point, but in nature viruses have huge variation, and biggest viruses found have a genome of two megabases, coding over 2000 different proteins. 7. Conscience To simplify, by conscience here I mean awareness of self and the capability of forming goals other than simple reproduction. This again goes beyond my field of expertise. Since in us humans our awareness of self is largely shaped by the environment we perceive with our senses, it is hard to imagine what the conscience of a big lump of undifferentiated cells would be like. However, it has an endless lifespan as long as its existence and its environment stay balanced. We are in the realm of speculation now. 8. Ability stealing This is the most complicated part. The viruses the hive sends out to gather new hosts could gain mutations that make them able to take different cells as hosts. Then the virus in a new cell can take in its genome bits of the hosts genes and according to its base coding compel the host to aggregate with the hive. There it will spread it's newly gained genes with the rest of the hive. The problems with this: - the outgoing viruses don't have a will or plan, the potential hosts they find is based on luck - the new genes taken in are random - the units returning to the hive have most probably gathered useless crap genetic code - when gathered is spread to the rest of the hive units it is like accumulation of useless trash which will sorta weigh the units down or be downright detrimental by integrating into needed genes - number of useful genes gathered / amount of thrash = tiny This all leads to the conclusion that the hive would need to somehow filter the genetic material brought by the returning units. This goes against the basic function of viruses: singular viruses gather genetic material at random and natural selection eliminates the ones that got something detrimental or even too much useless weight. Our hive however cannot die everytime a piece of garbage sequence is brought back. 9. Viruses in host brain I haven't been able to think of a way this would work. Even if a strain of virus could integrate itself in all of a brains neurons without killing the host animal and somehow form a new conscience there, it would die when the host animal dies. It wouldn't be able to make plans or at least see them through. Maybe a new animal contracts the strain and a new conscience develops in its brain, but it wouldn't have the memories of the previous one or even knowledge of its existence. **To recap.** A lasting **central mass** is needed, it has to be composed of **supporting host cells** each containing the viral genome to control it to **communicate** and **aggregate**. The hive "secretes" tons of viruses that bring back viable hosts and new genetic material. The genetic material has to be somehow filtered and tested. This being needs a huge amount of time and luck to develop when we remember **the driving forces of evolution: random mutations and natural selection.** Interesting problem! I hope my explanation didn't complicate things too much. ]
[Question] [ I am currently in the process of making a world, and am trying to ground it in scientific fact as much as possible. The world is a hard magic setting, and while fantastical creatures exist, they are usually rare or exaggerated re-tellings. Dragons, for instance, do exist, and can fly, but only short distances due to their weight. While Dragons rule the ground and the air around it, the Roc is king of the sky. I am not particularly scientifically minded myself, but have been looking at various means of making a creature that could have conceivably been created by evolution (and if necessary helped along somewhere by an incredibly powerful and rather insane wizard). Would it be possible to create a creature that does the following? 1. The Roc would be able to fly at high altitudes, up to 15,000 feet 2. The Roc would be able to maintain altitude for long periods of time, rarely returning to the Earth to land. 3. The ability to take off again, given that it is supposed to be massive in wingspan and would most likely be heavier than a typical bird by quite a lot. (I have thought about some sort of pulse jet assisted takeoff that would double as a means to escape more dangerous prey near the ground, where they are slower and more vulnerable. Perhaps using Nitrogen collected in flight, which is then ignited by powerful electric shock, generated in a similar way to an Electric Eel?) If necessary, some of this can be hand-waved as magic, although I am interested in limiting magical involvement in/with the Roc. Thank you in advance, and may you have a wonderful day. [Answer] That jet takeoff is going to be difficult to sustain. I think somebody else mentioned it can't be nitrogen. Maybe digestive gasses including hydrogen and methane? I'm not sure how efficient such a jet can be made. There will be refinements in the "nozzle" as it were. Jet engines are far more complicated than just burning stuff through a small hole. You need some way to build up a lot of pressure and push the result out the back. Maybe that means Roc's need to have some kind of very special lined container that can sustain this. Conceivably this lining is ablative, and needs to be regrown after use. Also there need to be improvements in ways of releasing large amounts of gas very quickly. Possibly it needs enzymes and special food to be able to pull this trick. Roc's might be desperate to obtain certain foods. Could be good drama there. The main problem is going to be a structure that can handle the forces of being pushed by a jet in combination with wings that can sustain long energy efficient flight. Folding their wings in (as most birds can already do) is not enough. Where-ever the jet pushes on your creature has to have a solid and strong structure that can sustain the force. You've got two very different competing requirements. The jet takeoff needs a strong skeleton to take that force. The long flight on big soaring wings needs light construction with lots of surface area. If you don't engineer that carefully you either get broken bones and internal damage, or you get something too heavy to fly for long. Possibly the wings can be folded in such a way that the long flight bones "weave" in some way to provide a temporary support for the rest of the creature. I'm having difficulty visualizing that. But imagine the critter is fairly long and skinny except for the flight muscles. And it can fold it's wings in to effectively make a cage that supports it's body in the direction of the jet. Maybe internal bones along its body are adapted to interlock with the wing bones. It would have very little ability to maneuver during the jet thrust. Probably pretty vulnerable to tumbling if it folds or unfolds its wings during flight. Possibly it can wield the jet in low-thrust or no-thrust mode as a weapon. Possibly it can emit the gas from both ends, breathing fire when it wants to attack. Enough energy to push the critter into flight will probably be enough to toast any threatening critters that don't have extremely tough hide. The evolutionary path to such a critter is tough to visualize. Maybe it started as the no-thrust weapon thing only? Then one learned to get a little thrust so it could expand its ability to land and take off in confined spaces. Or from difficult terrain. Maybe it started as just a gas sack storing small amounts of flammable. Then it started to develop chemicals to rapidly release the gas from some solid or liquid form. [Answer] > > The Roc would be able to fly at high altitudes, up to 15,000 feet > > > Many birds do this already. I remember reading that a flock of I think geese was seen by the crew of a commercial flight at cruise height, and they go 24000 feet and above. > > The Roc would be able to maintain altitude for long periods of time, rarely returning to the Earth to land. > > > Albatross do it routinely, they touch land only for reproducing, the rest of the time they soar the ocean > > The ability to take off again, given that it is supposed to be massive in wingspan and would most likely be heavier than a typical bird by quite a lot. > > > If they can fly, they cannot be heavier than a bird. Better, their weight to wing lift ratio cannot be worse than the corresponding one for a bird. Nitrogen, under standard pressure and temperatures, doesn't react with oxygen. However, if you want to give them some assistance for lift off, which due to the large wing span might be needed, better use their guts: they use symbiotic bacteria to produce methane, which is then ignited using a spark on ejection from their intestine or an adapted section of it, providing some additional thrust. [Answer] ### Design: The bigger and heavier the roc is, the larger the ratio of wings to body will be. If you want it to be huge, it might look like a small body suspended in between two massive sail-like wings made of an extremely thin, likely translucent membrane of flesh. ### Takeoff: For take-off purposes, these giant wings could be collapsible, folding in multiple times like an accordion:[![enter image description here](https://i.stack.imgur.com/Vuqy7.png)](https://i.stack.imgur.com/Vuqy7.png) The landed roc would haul its folded wings up a tall tree or a clifftop, then jump down while expanding its sail-wings to gain lift. These wings would have a very low beat frequency, but the roc could have smaller, paddle-like wings to produce thrust. It would use these to slowly gain altitude. The roc can also take off from a flat plain or desert using a large headwind: it just faces the wind and opens its wings, sending it backwards and upwards like a kite until it rises above that particular flow of air, then flies normally. The roc will choose its landing sites carefully to ensure that these features are present; otherwise, it will have difficulty taking off. The roc is most vulnerable on the ground, because its talons are used for dragging the rest of its body, and can't be used for fighting. If you think this is still implausible or just really want to add a combustion propulsion, you could think about using methane, which has 2 bonuses: 1. It's combustible: it can be released from under the roc, possibly in a mixture including a [pyrophoric](https://en.wikipedia.org/wiki/Pyrophoricity) gas such as diborane so that it ignites on contact with air. This boosts the roc into the air on a large explosion below its wings for an emergency takeoff. 2. It's lighter than air: when not used for quick evasive maneuvers, the methane gas sits in large sacs attached to the body of the roc, working as a [lifting gas](https://en.wikipedia.org/wiki/Lifting_gas) to make long flights easier. ### Flight: When high in the air, the roc would prey upon animals flying below it by partially folding its sail-wings and dropping down to grab the prey in the same talons it uses for climbing when on the ground. It then unfolds the sail-wings again and resumes its previous altitude. Potentially, the methane sacs could be used to kill particularly durable prey by ejecting fire underneath the roc towards the prey held in the talons. A more controlled flow of gas could be used as a flamethrower. [Answer] Long, long ago, there was a creature now known as *quetzalcoatlis Northropii*. It wasn't the largest of the pterosaurs, but it's the most complete large pterosaur (at least as of the last time I checked in detail). It was primarily a soaring creature, as are all very large birds, but paleontologists believe it could launch itself from level ground by using a move combining a jump with a wing sweep. The same was likely true of the "Texas pterosaur" which had a wingspan of roundly ten meters (that's similar to the span of a 4-seat Cessna, though the pterosaur was much lighter). As noted in another answer, any soaring bird is limited in altitude mainly by the need to breathe (and some of them apparently have a work around, likely akin to "supercharging" by compressing their air in their lungs momentarily before exhaling it). You can help by giving the Giant Roc at mechanism for locking its wings, so it needn't continually burn energy in its breast muscle to hold the wings in soaring position. This will lighten the bird. Worth noting that without the need to use muscle to hold the wings in position, there's no reason a soaring bird (or pterosaur) couldn't be as large as a modern sailplane -- 15 meter span is very reasonably attainable. Bone strength, as I understand it, isn't the main limitation -- it's muscle power. [Answer] There are birds on Earth with long takeoff ratios. Examples include the bufflehead and the coot, who paddle and then run on the water to assist their wings. On land, turkeys run a few steps; many large predators jump from a treetop or a cliff to get going. Remember - regardless of size, if a bird can fly it will have very low body density. ]
[Question] [ The [Guivre](https://en.m.wikipedia.org/wiki/Guivre) is an amphibious dragon from French mythology: [![enter image description here](https://i.stack.imgur.com/oHm1K.jpg)](https://i.stack.imgur.com/oHm1K.jpg) Many of its aspects are typical of Western dragons, but there are two which distinguish it from others: 1. Its breath causes disease 2. It cannot stand to look at a naked person. Hence it was chased out of France by streakers. How could an animal emit some kind of disease-causing agent from its mouth? What evolutionary reasons would there be for it to fear/avoid naked humans, even if that was a side-effect of some other behavioural adaptation? [Answer] # Breath that causes disease Though [the source](https://en.m.wikipedia.org/wiki/Guivre) says "venomous," you do not specify the "disease." What about breath that causes vomiting? If it smells like human vomit that does cause a lot of people to throw up in real life. It could also have elements of disgustingness that would lead to even more people heading for the buckets. If you'd like a more traditional disease, imagine [Zoonotic influenza](https://www.who.int/news-room/fact-sheets/detail/influenza-(avian-and-other-zoonotic)). We already have diseases like this: > > Influenza A viruses infect humans and many different animals. The > emergence of a new and very different influenza A virus with the > ability [sic] infect people and have sustained human to human transmission, > can cause an influenza pandemic...Aquatic birds are the primary > natural reservoir for most subtypes of influenza A viruses. Most cause > asymptomatic or mild infection in birds, where the range of symptoms > depends on the virus properties. > > > It's not a stretch to imagine that an aquatic flying reptile has similar physiology to an aquatic bird. So imagine a flu that may or may not cause symptoms in a guivre. The guivres recover and stay carriers. The flu is airborne (though direct contact with the guivre's breath is needed in most cases) and can cross species lines and infect humans. How bad the infection is is up to you. You can also combine these things. A big wham of guivre breath in a human's face causes immediate vomiting and then flu symptoms a few days later. # Fear of naked humans The naked human bit (not in your source) would have to be psychological/behavioral. Perhaps over time the guivre has learned that humans with coverings over their faces are safe to be around (it's protection from the guivre's breath; the humans know it protects against the smell at least). A human without a face covering leads to punishment (humans who suddenly vomit are not kind, and they cause people to yell a lot and probably beat the guivres). Guivres are smart dragons but not quite cognitively advanced enough to understand the difference between covering the face and covering the body and why it matters. Nakedness scares them because they associate cloth on humans with calmness and kindness and absence of cloth with screaming and throwing things. The humans aren't bright enough either to understand that the sudden vomiting isn't part of the disease that comes a few days later. Rather, they think it's the first symptom (and they aren't wrong from a certain standpoint, just a biological one). So if a guivre causes someone to vomit, this is very very scary and they react accordingly. The guivres in turn are terrified. [Answer] Real world [Komodo Dragons](https://en.wikipedia.org/wiki/Komodo_dragon) carry disease in their saliva, so that part already has a real world precedence. Carnivorous mouths are not the cleanest places in the world, so disease carrying may be the rule rather than the exception. Aversion to the naked male form also has some precedence. Many heterosexual male humans exhibit homophobia which mimics that exact behavior. Here are a couple methods for getting that behavior into your dragons... * The dragons are domesticated and live with humans regularly. Perhaps the particular humans who raise these dragons (despite being french) are extremely homophobic. The dragons may have learned this behavior from their human companions. * The dragons are the product of a human super soldier program. They were created in a lab by transferring the brain of human warriors into the powerful dragon bodies; and the humans who volunteered for the program happen to be homophobic. * The dragons are the product of a human biological battle drone programs. They were created in a lab by implanting radio receivers in their existing brains such that remote humans can "pilot" them; and the human pilots happen to be homophobic. * Perhaps there is a non-human bipedal apex predator in the dragon's natural environment which carries its most offensive weapon in it's frontal groin area. This predator might have a gecko-like projectile tongue (tipped with a dragon targeting diseased saliva) which shoots out from the camouflage of human appearing dangling sex organs. [Answer] The guivre might have evolved from a predatory amphibian. This amphibian may have used a venomous bite to hunt. To better access more of its prey's flesh, its head and jaws may increase in size and become stronger. This may cause them to kill their prey with the bite alone, without using venom. However, they may start to spit their venom out of their mouth at prey, to blind or otherwise injure the prey. This may lead to the venom turning into a terrible poison, that could easily blind prey or, more likely, predators. These creatures may become larger, bone-eating creatures, with a more robust ribcage. Due to being slow, they may evolve to try and grab onto fast prey, so that they can kill it more easily. This may lead to their body becoming longer and more flexible, eventually taking on a serpentine form. These serpents, due to their large food intake and surplus of energy, may become smarter, to try and target smarter prey, and avoid smarter predators. This may lead to them becoming smart enough to devise some method of communication, which would gradually be improved by adaptation. The surplus of energy may also allow them to gain impressive display structures, such as a pair of sharp horns above the eyes. Eventually, they may encounter humans, and join their societies. However, soon, the humans may grow to dislike them, and reject them from their cities. There may still be some guivres may be raised in cities, and so grow accustomed to the city's rules and customs, but they would soon be rejected, and either run away, or go on a rampage through the city that rejected them ]
[Question] [ In my Conworld's system, There is a porous asteroid large enough to be a dwarf planet (but it's mass is too small to pull it into a spherical shape) that has rings. How they got there, nobody knows. But could they have a prolonged orbit around the body without interference, unless from another asteroid? [Answer] Yup! This is possible, and a number of small bodies in the Solar System have rings: * [**Haumea**](https://en.wikipedia.org/wiki/Haumea#Ring), a dwarf planet in the outer Solar System, [was recently discovered to have rings](http://adsabs.harvard.edu/abs/2017Natur.550..219O), which lie inside its Roche limit. * [**Chariklo**](https://en.wikipedia.org/wiki/10199_Chariklo), a very large asteroid, [has two known rings](http://adsabs.harvard.edu/abs/2014Natur.508...72B). * [**Chiron**](https://en.wikipedia.org/wiki/2060_Chiron), another minor planet, is *suspected* to have rings, but these have not been confirmed. Minor planets orbit far away from each other and have such weak gravitational fields that they are unlikely to destabilize each other, barring an extreme close encounter. These rings will eventually dissipate, [as all rings do](http://adsabs.harvard.edu/abs/1993AREPS..21..487E). Viscous spreading is one culprit, and for these minor planets, the effect may be more pronounced because of the nonexistence of shepherd moons around these bodies. In at least Haumea's case, an orbital resonance provides short-term stability, but not long-term stability. [Answer] ## 10199 Chariklo [![enter image description here](https://sservi.nasa.gov/wp-content/uploads/2014/03/3-27-14_chariklo-382x150.jpg)](https://sservi.nasa.gov/wp-content/uploads/2014/03/3-27-14_chariklo-382x150.jpg) Picture Charlico Nature bet you to the punch. This is 10199 Chariklo [1], a Centaur astroid orbiting between Saturn and Uranus. It has a radius of 151 km. As you asked for an elongated body, I see no reason why objects like these two couldnt have the same kind of ring system. In fact the artwork shown above could be inaccurate in showing an nearlt spherical body. Many astroids and comets we visited had weird shapes. [![enter image description here](https://upload.wikimedia.org/wikipedia/commons/thumb/6/68/PIA02475_Eros%27_Bland_Butterscotch_Colors.jpg/319px-PIA02475_Eros%27_Bland_Butterscotch_Colors.jpg)](https://upload.wikimedia.org/wikipedia/commons/thumb/6/68/PIA02475_Eros%27_Bland_Butterscotch_Colors.jpg/319px-PIA02475_Eros%27_Bland_Butterscotch_Colors.jpg) Eros pic [![enter image description here](https://cdn.arstechnica.net/wp-content/uploads/2019/02/thule.jpg)](https://cdn.arstechnica.net/wp-content/uploads/2019/02/thule.jpg) Ultima Thule pic As for the zones where the rings could exist, the rings should be within the planets roche limit [2]. $r = 2.44 \* \sqrt[3]{\frac{pp}{ps}}$ $r$ = roche limit $pp$ = density primary object (your asteroid) $ps$ = density secondary object (this was the object ripped appart to form the ring. Assume a sphere with the density of the rock-ice mixture you desire ($3 g/cm^2$ will work as an approximation)) This should give you the roach limit for a given object. Just place the rings somewhere inside it. [1] <https://solarsystem.nasa.gov/asteroids-comets-and-meteors/asteroids/10199-chariklo/in-depth/> [2] <https://en.m.wikipedia.org/wiki/Roche_limit> [Answer] Two implications. 1: A body large enough to be a dwarf planet that was cigar shaped. <http://www.astronomy.com/magazine/ask-astro/2017/08/the-diameter-of-spherical-bodies> > > For these igneous planetesimals, the diameter needed to overcome rigid > body forces and become round is about 620 miles (1,000km). The main > belt asteroid Vesta is 326 miles (525km) in diameter. In its early > history, Vesta’s interior was at least partially molten and may at one > time have been in hydrostatic equilibrium; however, after cooling, > Vesta was battered out of round by large impacts. > > > So something the right size that is not round has either been "battered out of round" like Vesta, or is of a composition such that it is much less dense than typical asteroids - maybe porous, like Hyperion. Or hollow... --- 2: An object with low mass might retain a ring thru electrostatics instead of (just) gravity. Electrostatics are relevant for existing planetary rings. Fast moving dust comprising the ring might be attracted by a combination of electrostatic attraction and gravity, and so persist around this lightweight cigar-shaped planetlet. ]
[Question] [ A defining factor of my world is the hardships inhabitants have to face when surviving long seasons. Due to the extreme length of a year, time is largely measured by moon cycles. I need to make sure though that the solar/luna cycles are a) Generally possible, and b) able to sustain life. Here is the general premise of my solar/luna cycle: * The Planet's sun is many times larger than the Earth's sun (no exact size determined yet) * The Planet takes 120\* Earth-Years to orbit * The Planet is ~1.5x the size of the Earth, and ~1.5x the mass. * The Planet has an axial tilt, giving it Summers & Winters (and Spring & Autumn) * The Moon takes 1.9 Earth-Years to orbit the Planet * The Moon is visible in the Planet's sky, similar in size to Earth's Moon (or even appearing slightly bigger) So my questions are: * Is it possible to have a habitable planet that takes 160 Earth-Years to orbit the sun if the sun is sufficiently large enough, and the planet's orbital distance is sufficiently far away? * Is it possible to have a moon that takes 1.9 Earth-Years to orbit a planet, and if so: how big would the moon have to be for it to be visible in the sky (as described above) when considering the (yet-uncalculated) distance its orbit would have to be for it to take 1.9 Earth-Years? Any help would be greatly appreciated, even if it's pointing me in the direction of tools and resources that could help me calculate this by myself. **EDIT: I made a mistake in my original post. The length of the planet's orbit is 120 Earth-Years, not 160. I've also changed it so that the moon's cycle is now only ~48.8 Earth Days. I imagine this is a lot more realistic.** Thanks for all your replies so far! [Answer] **The planet's orbit.** [Neptune](https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html) orbits the Sun in 165 years. The long dimension of its orbital ellipse is 30 times that of the Earth. This is an example of the square-cube law: All other things being equal, the square of the orbital time is proportional to the cube of the long dimension of the orbital ellipse. So for a 160 year orbit, the long dimension of the orbital ellipse would be 29.5 times that of Earth's orbit. This distance needs to be further increased by the cube root of the increase in the star's mass. Multiplying by the cube root of 10.9 makes this distance be 65 times that of Earth's orbit. > > (distance) is proportional to (period)^(2/3) \* (central mass)^(1/3) > > > but if the central mass is large enough to give the same power per unit area, > > (distance) is proportional to (period)^(42/51) > > so the factor of 65.3 = 160^(42/51) > > or 51.5 = 120^(42/51) > > > By the way, all of the numbers in this answer are absurdly precise. Rounding them off is probably a good idea. If you want to calculate similar factors, but for a different orbital period, you can copy-and-paste these formulas (on the right-hand sides of the equals signs, but before the "for" notes) into [WolframAlpha](https://www.wolframalpha.com/). Then change the input variable values, and press the compute button (the = sign). The biggest mistakes will be in my choices of assumptions and formulas, not in how the calculations are done. **The star's size** All other things being equal, the light per unit area received from a star is inversely proportional to the square of the distance from the star. For 29.5 times the Earth's distance, that is a factor of 868. For stars on the [main sequence](https://www.infogalactic.com/info/Main_sequence), a star about 6.9 times as massive as the Sun would be about 868 times more powerful than the Sun. Combining the inverse-square law, the square-cube law, the [effect of stellar mass on orbital period](https://www.infogalactic.com/info/Orbital_period#Small_body_orbiting_a_central_body), and the relationship between stellar mass and luminosity means that the 6.9 factor needs to be raised to a power of 21/17, or to 10.9. For 65 times the Earth's distance, the star's power output needs to be 4,200 times the Sun's output, which corresponds to the 10.9-fold increase in the star's mass. Logan Kearsley is correct that if we are trying to match the power per unit area using a star on the main sequence (just like the Sun, but bigger, hotter, and bluer), > > (star mass) is proportional to (orbit time)^(8/17), > > so the factor of 10.9 = (160)^(8/17) > > or 9.5 = (120)^(8/17) > > > (power needed) is proportional to (distance)^2 > > so 4,200 = 65^2 for 160-year orbit > > or 2,700 = 52^2 for 120-year orbit > > > In general, the more powerful the star, the faster it runs out of fuel. A star that puts out 868 times the power of the Sun would have a short life. If the Sun can be expected to have a total life of 10,000,000,000 years, a star that puts out 868 times the power [might last](https://www.astronomynotes.com/evolutn/s2.htm) 75 million years. A star that puts out 4,200 times the power of the Sun might last 25 million years. > > (lifespan) is proportional to (star mass) / (power output) > > so 25 million years = 10,000 million years \* 10.9 / 4,200 for 160-year orbit > > or 35 million years = 10,000 million years \* 9.5 / 2,700 for 120-year orbit > > > **The moon's orbit** 1.9 years is about 24 times as long as Luna's orbital period, so the proposed moon orbits about 8.32 times as far from the planet as Luna is from Earth. If the moon moves from east to west, and has an apparent cycle of 48.8 days, its orbital period is 47.8 / [27.3](https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question32.html) = 1.75 times that of Luna. If the planet is 1.5 times the mass of Earth, the moon has > > (distance) is proportional to (period)^(2/3) \* (central mass)^(1/3) > > or a factor of 1.66 = (1.75)^(2/3) \* (1.5)^(1/3) times that of Luna > > > **The revised moon's size is plausible** To take up the same amount of space in the sky, the revised moon would need to be 1.66 times the diameter of Luna, or 4.6 times the volume of Luna. As long as the revised moon is not much denser than Luna, its mass is still much smaller than that of the planet. > > (diameter) is proportional to (distance). > > > (volume) is proportional to (diameter)^3, > > so the factor of 4.6 = (1.66)^3 > > > **Mitigation** Have you considered the solution that Piers Anthony used for providing enough power per unit area for human colonization of the Jupiter and Saturn systems? The equivalent of giant lenses that focus light on the colony worlds. He used this in his *[Bio of a Space Tyrant](https://rads.stackoverflow.com/amzn/click/com/0380896850)* series. More practical -- but explicitly artificial and expensive -- versions include reflector satellites around your planet (*a la* Bujold's "soletta array" around *[Komarr](https://www.baen.com/komarr.html)*), and beaming power from satellites in the inner solar system (*a la* Ringo's Very Scary Array in the *[Troy Rising](https://rads.stackoverflow.com/amzn/click/com/B00APAH7T2)* series). [Answer] In order to get a longer orbital period, you need a larger orbital radius--and to keep the planet warm enough at a larger radius, you need a larger star. The luminosity equation for stars between 2 and 55 solar masses is approximately $L = 1.4M^{3.5}$. The necessary radius scales with the square root of luminosity, and orbital period scales with star mass and orbital radius as $T = \sqrt{R^3/M}$ With a little algebra, we can solve for stellar mass M and radius R in given T = 160 years: $M = (\frac{T}{\sqrt{1.372}})^{8/17} = 10.114$ $R = \sqrt{1.4}(\frac{T}{\sqrt{1.372}})^{14/17} = 67.868$ So, your star is a little over 10 times as massive as the sun, and your planet orbits at nearly 68 AUs--considerably farther out than Pluto! Such a star will only live for a little over 3 million years, so life did not originate naturally on this planet. It was colonized and terraformed--or magic did it. The sun will not have a noticeable disk in the sky; it will appear as an actinic blue point source, producing sharp shadows and extremely rapid sunsets and sunrises. Now, we have the "moon" to worry about. Basically, you can't have a moon like that--but that doesn't mean you can't have the *effect* of a moon like that. It just won't actually be a moon--rather, your planet will be a moon of a gas giant (with a 1.9 year orbital period, and a system that's only a couple million years old at best, you don't need to worry about tidal locking). Gas giants don't get much bigger than Jupiter--when you add more mass, they just get more dense. So, we'll assume that the gas giant has Jupiter's radius. To make it appear the same size in the sky as Earth's moon (about half a degree across), your planet will need to orbit the gas giant at 16,384,786 km (or slightly less, to make it slightly bigger), or a little over 1/10th of an AU. Given that distance and the required orbital period of 1.9 years, we can calculate a mass of 7.238e26kg; that's a little over a third Jupiter's actual mass, and a little bit more than Saturn's. So, assuming Jupiter's radius may be a *little* optimistic, but it definitely seems plausible that there's a range of gas giant masses and orbital distances which would make that all work out. Additionally, while an orbital distance of a tenth of an AU may seem overly large for the gas giant to retain your planet as a moon, it turns out that given that mass it would have a Hill sphere of about 1.5 AU, so the system should be perfectly stable and well-behaved. [Answer] The equation which defines orbital periods is Kepler's third: $$ \frac{T^2}{R^3} = \frac{4\pi^2}{GM} $$ Where: $T$ = The orbital period; You want it to be 1.9 years = $5.992 \times 10^7$ seconds $R$ = Mean distance from the center of mass. $G$ = The gravitational constant ($6.674 \times 10^{-8} cm^3 g^{−1}s^{−2}$) $M$ = The sum of the masses involved Let's plug some numbers in there. $$ \frac{(5.992 \times 10^7)^2}{R^3} = \frac{4\pi^2}{6.674\times10^{-8}\times (8.958\times10^{24} + 7.347\times10^{22})} $$ The numbers in the parenthesis are the mass of 1.5 earths plus the mass of a moon, by the way. [Solving it](https://www.wolframalpha.com/input/?i=r%5E3+%3D+(6.674+*+10%5E-8+*+8.958+*+10%5E24+*+7.347+*+10%5E22+*+(5.992+*+10%5E7)%5E2)%2F(4+*+3.1416%5E2)) gives us approximatelly $1.587 \times 10^{18}$ meters, or a quadrillion and a half of kilometers. For comparison, our Moon is about 384,400 kilometers away from us, which is slightly over a light second. The moon in your world, though, would be further than 150 light years from the planet. The only way for this to work so that your moon orbits your planet is if both are deep in intergalactic space, away from any other significant mass. Maybe even not then; I haven't bothered to calculate the escape speed for your planet at that altitude, which is probably less than a fraction of an atomic radius per second. --- The orbital period for your planet involves less mathing around. Unfortunately, contrary to what I said in the comments, now I think it is not possible. A sol-like star will eventually die and expel much of its outer material, which may form a planetary nebula; The remains become a white dwarf, which is both less mass massive than the original star and brighter. This is important. Look at the equation at the beginning of my answer again. Let's twist it a little, while keeping it the same: $$T^2GM = 4\pi^2R^3$$ This means that, for a fixed mean distance ($R$), time and total mass are inversely proportional. Reduce the mass and you have longer periods. [A white dwarf may be hotter than the sun for billions of years](https://en.wikipedia.org/wiki/White_dwarf#Radiation_and_cooling), which is long enough for life to form on a captured planet, or to rise again on a planet devastated by the original star's death. This means it will output more energy. Meanwhile, since it'll be less massive, planet periods will be longer. For a remaining mass of half a sun, the orbital period you want would be found at the distance Jupiter is from the sun. But even though the star might be up to 40% hotter than the sun, the distance involved and the fact that the star is smaller means less radiation. Your planet's surface temperature would be something between Titan's and Europa's, both of which are really cold. One alternative to heat it up is to give it a hellish atmosphere like Venus's, but that is not compatible with life as we know it. You may have to handwave it, or accept smaller numbers. Orbiting around a half-solar mass white dwarf would mean one orbit for every four real Earth years. [Answer] > > •Is it possible to have a habitable planet that takes 160 Earth-Years to orbit the sun if the sun is sufficiently large enough, and the planet's orbital distance is sufficiently far away? > > > The habitable zone depends on the luminosity of the star. The brighter the star, the further away from it is the habitable zone. The further away the planet is, the longer it takes to orbit the star. As a 0th order approximation, it's an assumption that holds true. > > •Is it possible to have a moon that takes 1.9 Earth-Years to orbit a planet, and if so: how big would the moon have to be for it to be visible in the sky (as described above) when considering the (yet-uncalculated) distance its orbit would have to be for it to take 1.9 Earth-Years? > > > The Earth takes one year to orbit the Sun. The Sun has in the sky the same apparent size of the Moon. I have the feeling, again, a 0th order approximation, that such a long lasting orbital period is not suitable for a moon together with the other constrains you give. I suspect the moon would either be captured by some other attractor, or simply be so big to not be a moon. [Answer] **Your moon's orbit is not possible, it exceeds the [Hill Sphere Radius](https://en.wikipedia.org/wiki/Hill_sphere) by a large margin.** Jasper did most of the required background legwork already. The most stable moon orbit is a circular orbit (zero eccentricity), it which case the Hill Sphere radius is expressed as HR = A \* (m/3M)^(1/3) Where A is the orbital radius of the planet, m is the mass of the planet, and M is the mass of the star. Using Alpha = 1 AU Substituting using earth & sun parameters with Jaspers calculations. HR = ((1.5\*5.97e24 kg) / (3\*6.65\*1.88e30 kg))^(1/3) HR = 29 \* 6.09e-3 AU = 0.29 AU No moon orbit larger than 0.29 AU is stable. I.e., 24 million miles / 43.5 million km. This is smaller than the required 593 \* lunar orbit radius (239,000 miles / 385,000 km) calculated by Jasper. ]
[Question] [ My story for a video game has some kind of "enemy" (think "the Others" from Lost—little is known about them; they have control over a small settlement or two and appear to be engaging in some manner of industry involving a network of abandoned coal mines). I'm not really looking to flesh this back-story out since I might do that myself, but I have the opinion that an unexpected volcanic eruption is going to be a good premise for a "run-for-your-life" part of the game. It's occurred to me that a volcano and coal mine are two kinds of "rather deep holes in the ground". So how can a small team of careless idiots in charge of mining equipment accidentally cause an eruption? Is it really just a case of digging? [Answer] Slight frame challenge...what if they were working around a volcano that was currently quiet but not completely dorment? One that could go at any time but, for now, was safe to be around as long as you weren't right up in it. I've visited volcanos like that...they had some steam coming out but I could get fairly close. There was a fence to keep visitors away from dangerous parts. After I left that country, I heard the volcano became more active and the entire area was closed. So what if this volcano was going to erupt in a month or two? The characters don't know when or if this will happen and absolutely nothing they do or don't do can change this from happening. But that mining activity (or whatever it turns out they're doing in the mine) makes just enough of a difference in the landscape that, when the volcano blows, the lava changes course. What would have been a situation of *"we should get out of here because the air is bad and let's not take chances now that the volcano is active"* into a \*"holy \*\*\*\*! the lava is heading right for us! Run for your life!"\* [Answer] They really can't, sorry. Even setting off nukes in mine shafts doesn't trigger volcanoes! The sort of levels of pressure and mass involved in volcanic eruptions are just so far outside human scales that the chance we do anything is minuscule. Your best bet may be to have a pocket of superheated and pressurized gas or mud. Breaking through into that could be devastating to anyone inside the mine but even then the effects on the surface would be minor. Something you could do is have a lake with dissolved carbon dioxide. Human activity could trigger an avalanch or landside which then causes a [linmic eruption](https://en.wikipedia.org/wiki/Limnic_eruption) such as at [Lake Nyos](https://en.wikipedia.org/wiki/Lake_Nyos). That wouldn't have the same visual spectacle as a volcanic eruption though, everyone just falls over unconscious or dead. [Answer] They can, but they'd have to be *really* stupid and *really, really* unlucky. Something like the Howard brothers in a nightmare of the Marx brothers crossed with the lovechild of Agent 46 and Mr. Bean on a bad day, unlucky and stupid. The only real way this is likely to happen if the above geniuses decided to mine a caldera of a dormant volcano, and weakened the crust enough that the pressure of lava underneath forced it open the rest of the way. A couple of hundred metre deep shaft, just where the crust is thinnest should do it [Answer] Tim B's point is well taken, the human scale of effect on geology is insufficient to directly reactivate a dormant volcano, but most disasters are the result of a cascade of incidents that result in devastation. As in the domino effect a relatively small action can trigger a series of larger consequences that ultimately lead to a disaster. The diverting of a water source could inundate descending lava tubes that lead near a geological instability. The resulting subterranean steam explosions into subsurface caverns that collapse might be sufficient to trigger a fault movement in a subduction zone, resulting in your desired volcanic activity. Although the cascade failure effect makes it possible for the event to occur, your premise is confounded by the fact that it doesn't require "reckless idiots" to trigger the first domino. If people knew the diverting of the water source would cause the chain reaction, they would be evil agents of chaos. If the people didn't know they would be innocent instigators. ]
[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/132388/edit). Closed 5 years ago. [Improve this question](/posts/132388/edit) A group of people get trapped in an unknown construction. Uninhabited. Nobody takes care of the place. There are no living creatures around. They were prepared to go inside and spend some time there, but not on long term. They have some equipment - sleeping bags, some food, some water. But they were prepared to go in for a couple of days maximum, and they definitely weren't prepared for such a long journey. They cannot find the exit for three weeks. **Desciption of the place**: This is a construction by an alien sentient race that does not know humans. It's a vast closed place with no exit and no food lying around. They get lost and spend about three weeks time wandering. It's a alien projection of what a human lodging might look like. It includes artificial and natural elements, as a mish-mash of wooden corridors, cave tunnels, and passages that don't resemble much here on Earth. There is magic in this particular construction. The world around isn't exactly magical (at least not the type of magic humans can use), so the characters are unfamiliar with the setting, but in the construction weird things can definitely happen. This is how they can't find an exit for three weeks: the corridors keep changing and making wormholes, so it's impossible for them to trace back. The reason why there is no food lying around is because it is not built for humans. Instead, the aliens built a model, sort of a decoration, so they wouldn't put human food in there on purpose. Even if they wanted to, the aliens don't have a concept of what a human needs to survive. It is meant to imitate the elements you could find around humans (such as structures of buildings and natural structures), but there wouldn't be details you find in humans' daily lives. There could be sparse water sources or other ways for the humans to get water, for example: open roofs, ponds, magic streams, etc... Outside the construct, there isn't anything extraordinary. It's standing on a grass plain not far from a large city. **Rules**: 1. Whatever is inside the castle might not make sense to the humans, even though they would be able to describe it. For example, a brick corridor might lead into an underground tunnel that leads back to the same corridor. It's not typical for human architecture, but it's possible to imagine and retell. 2. Space is weird. You cannot retrace your steps, because whatever is behind you changes. 3. The basic architecture is passages and halls and rooms and open spaces, but all the places are mostly bare. No decoration inside, no objects. 4. Basic setting elements would include: wood, brick, ground, rock, glass, water. they can be arranged in a number of ways to make it seem like the passages change, even though in the end the journey does become monotone. 5. Other than that, modifications might apply. **Question**: Given that there is no evident source of food, what element could be found in such a place that would either nourish a group of humans, or give them an alternative source of energy? (So as not to make the question too broad, assume that water is not an issue). [Answer] The main issue for them will be water. According to [this website](https://www.healthline.com/health/food-nutrition/how-long-can-you-live-without-water#bodily-response), you can live for weeks, even months, without food (as those on hunger strikes do), as long as you have access to water. The effects of dehydration are serious and fatal, and far faster than starvation - a matter of days (though it depends on various factors such as age, height, weight, sex, etc. as to exactly how long you’ll last). If your castle is abandoned, perhaps derelict, they may be able to find an open roof - too high for them to climb out of, but with access to the sky for them to collect rainwater, for example. I’d advise your explorers to make finding water a priority, and once they’ve sourced that, staying as inactive as possible to conserve energy, until the castle lets them out again. [Answer] [As K. Price said, water is the most pressing issue.](https://worldbuilding.stackexchange.com/a/132389/21222) Once you've got a source of drinkable water figured out, you can dolve the food problem through cannibalism. According to [XKCD What If no. 105](https://what-if.xkcd.com/105/): > > If the average human weighs 50 kilograms and eats a couple thousand calories per day, then—according to Ryan North—then one person contains enough meat to feed another person for about a month. > > > So if half the team eats the other half, you've got some 30 days of provisions. How much they can last in this scenario depends on the size of the team. A group of $2^n$ people will last $n$ months, i.e.: 16 people will last 4 months, with the last cannibal running out of food at the end of the fourth month. [Answer] According to the [Rule of 3s](https://en.wikipedia.org/wiki/Rule_of_threes_(survival)), you can survive * 3 minutes without air * 3 hours in extreme heat/cold * 3 days without water * 3 weeks without food None of which will be very pleasant. The main problem your explorers will have is water. With rationing (assuming they realise they're locked in within a day), they can eke out their food so they don't feel starving. If there is water dripping through the castle's roof, then they should be able to catch it in their canteens. If they have pan or other containers with a larger surface area, then this is easier. [Answer] Assuming this castle isn't located in the Atacama Desert, water shouldn't be too hard to find. An old abandonned castle will certainly have wells at least and possibly cisterns with water. Lower levels may be infiltrated by ground water. Catching rain water may also be a viable option. Food will be much more difficult. The kitchens will be bare and any food left behind will have long ago been eaten by rats, eaten by bugs or rotted away. That said, castles often had **[gardens](https://www.medieval-castle.com/medieval_garden.htm)**. Your adventurers might be able to find some fruit trees or vines (if the season is right), or perhaps some wild onions or other edible herbs growing wild. Not a lot, perhaps, but in conjunction with any rats they're able to trap, will go a long way towards making the little critters more palatable! Be on the lookout especially for leeks and carrots and onions and big juicy rats. [![enter image description here](https://i.stack.imgur.com/EocFk.jpg)](https://i.stack.imgur.com/EocFk.jpg) [Answer] **Your adventurers set out with a generous rainy day fund.** [![obese ninjas](https://i.stack.imgur.com/DQ3r1.jpg)](https://i.stack.imgur.com/DQ3r1.jpg) <https://tapirullanza.com/tag/the-morbidly-obese-ninja/> <https://www.quora.com/How-long-would-it-take-an-obese-person-to-die-of-hunger> > > Back in June of 1965, a Scotsman weighing 207 kilograms, described as > "grossly obese" and hereafter known only as Mr A B, turned up at the > Department of Medicine at the Royal Infirmary in Dundee. > > > He was sick of being fat and wanted to lose weight by eating nothing > and living off his body fat. He told the hospital staff he was going > to fast flat out, whatever they said, so they may as well monitor him > along the way. > > > He ended up fasting for one year and 17 days — that's right, he ate no > food at all for over a year. He lived entirely off his copious body > fat, in the end losing about 125 kilograms of weight. > > > So too your explorers. These are not buff, lithe athletes with 6-pack abs. These are individuals who have accumulated considerable caloric reserves, and wind up grateful that is the case. A pound of fat has 3500 calories in it, easily enough to fuel a day of moderate activity. 3 weeks is just 21 pounds and each one of this crew has a lot more than 21 pounds extra. They complain loudly along the way, but are in no risk of starving to death over the course of just 3 weeks. [Answer] Water is the main issue, they need some source of it, be it rain filtering in through the ceiling or a well or they are done. They can't last more than a week normally. Could they dig a hole in the ground without upseting the condition of emprisonement? They would get exhausted in the process but to find a layer of water would be their last possibility. Food: it depends on what kind of ecosystem you have down there. Plants without sun are out of the question but you can have fungus. Is there some secret hideout of food for rats to be around? What about soil? If you have worms, you could have some insects like ground beetles, along with centipedes and flatworms. All of these have a lot of protein but they will lack of carbohydrates so they will eat up their muscle very quick. I don't take in account the risk of poisoning. [Answer] If the very land is magical somehow I prefer that the castle actually take care of them sometimes. They wander into a store-room and there is food but then the magic re-arranges the room and forces them out. I'm not sure that 'exploration' exactly applies to a place that does not remain stable, that there is no reliable way to backtrack but if you don't want (most) of the setting itself to be dangerous a lot can be done with this. And even better if they are from someplace without magic watching a wall morph into a hallway tells them something weird is going on. ]
[Question] [ It is the near-future. Breakthrough, mass produced carbon nanotubes have been invented and are relatively cheap. These nanotubes have the [properties that we would expect](https://en.wikipedia.org/wiki/Carbon_nanotube#Properties), and are manufactured in 'ropes' up to 10 cm long with a tensile strength of 200 GPa. What is the most effective way to use these fibers to build super-tall megastructures in cities? [Answer] The main limiting factors for height in skyscrapers are: * Structural: Not in so far we can't create tall towers, but more in that wind causes lateral deflection and oscillation, creating a discernible movement to occupants which can be distressing. * Natural light: Most building codes stipulate minimum levels of natural light that must be present in habitable spaces. A taller tower often means a wider tower, and the wider the base the less natural light can penetrate to the interior. * Economic: Creating tall skyscrapers creates a lot of lettable floor area to get income from yes - however this is balanced with cost of construction and market demand. The tallest tower in Dubai is funded differently to most market-driven construction in capitals. Flooding the market with lettable floor area is a good way to kill the market, unless the economic purpose of the tower is supplanted with political or other purposes. * Lifts: Yes, I went to a seminar on lift design and the consultant's main message is that lifts are a major determinant for height. People only wait for a short while before getting to the floor they need to get to. Keep in mind lifts have height limits, and usually sky lobbies need to be implemented too. So structure is actually a small part of all the considerations to do with height. However, having said that, to eliminate this limitation it is worth noting nanotubes are good in tension, but not so good in lateral strength or compressive strength. The best way to use the new technology is to create pretensioned perimeter elements to increase the structural rigidity and prevent lateral movement from wind forces. A tower with exposed structure that utilises this technique is the fairly modest Central Park tower in Perth, Western Australia: [![enter image description here](https://i.stack.imgur.com/rsypI.jpg)](https://i.stack.imgur.com/rsypI.jpg) The architects exposed the structure - but in short a discussion with the structural engineer was that visible column and 'triangle' at the tower top are in tension to reduce this movement. Your nanotubes would enable this principle to create substantially less deflection, and thus a higher tower (how much I cannot say though). [Answer] Considering that carbon nanotubes as a "rope" fiber would have extremely strong tensile strength but no compressive strength, the question then becomes: How do I use tensile strength to help avoid compression? There are at least three ways to do this, two of which are already common in modern engineering. 1) Air supported structures - Imagine a giant, vertical dirigible. Now imagine many of these, long and narrow, used as a support structure. A carbon nanotube woven fabric could be made to withstand very high pressures within, creating a very rigid "beam" that is, strictly speaking, a balloon. (Side note, balloon animals for giants!) 2) Pretension - Similar to reinforced concrete, tension added to compression members before loading is already used to minimize flexing, allowing taller construction. 3) Active support structures - This one is my favorite, and incidentally, while requiring the most advanced technology, is capable of the tallest structures. Similar to the air-supported concept, active structures use a non-solid medium to keep a structure's form. Structural support provides thrust. That thrust is usually static, and it is exactly opposite the downward force of gravity. Now, structural supports are not the only way to provide thrust - otherwise it would be very hard to get rockets off the ground. It's possible to use such an active system to support a building as well, but a rocket would not do, as the reaction mass is continuously lost. Instead, the idea for such a structure (commonly called a space fountain) is to force magnetically charged particulate matter in a stream through an evacuated tube, where they will be deflected back downward at the top through a return tube. That deflection provides the thrust to support the building. So far, this is irrelevant to the use of high tensile strength cables such as the carbon nanotube ropes. However, we would want our fountain tower to be rigid, to avoid our penthouse guests losing their lunch. Hmmmm, rigidity? This calls to mind the second method I described. Tension would allow for excess thrust to hold the tower at precisely the wanted height, and by using sufficiently angled stay lines to compensate for sideways thrust (from wind, earthquakes, etc.), just as on the mast of a ship, the tower would be held vertical. [Answer] You could use them to lighten the load of the buildings with vacuum balloons... > > The density of air at standard temperature and pressure is 1.28 g/l, so 1 litre of displaced air has sufficient buoyant force to lift 1.28 g. – [Wikipedia](https://en.wikipedia.org/wiki/Vacuum_airship) > > > ...on Venus: > > Of all known planets and moons of the Sun system only the Venusian atmosphere has [Lana atmospheric ratio] big enough to surpass [Lana coefficient] for such materials as some composites (below altitude of ca. 15 km) and graphene (below altitude of ca. 40 km). – *ibid.* > > > [Answer] In addition to Thorne's answer, you can also combine this with active support. The idea is the same as with a sheet of paper above fire - you bounce something off the bottom of the supported structure. You can find a great explanation of this and many more things on [Isaac Arthur's](https://www.youtube.com/watch?v=MQLDwY-LT_o&list=PLIIOUpOge0LtW77TNvgrWWu5OC3EOwqxQ&index=13) youtube channel [Answer] Carbon nanotubes have a great tensile strength. If you want to use them for building a skyscraper, you need to have them work under tension, to properly use their above said tensile strength. Where in a skyscraper do we have tension? Not on the pillars: they mostly work in compression, and only when the skyscraper bend under lateral load (mostly due to wind) they have tensional solicitation. For these components you may want to still use steel and concrete. But if you want to lay the horizontal beams to sustain floors and ceilings, there carbon nanotubes can help you. The bottom side of a loaded beam is subjected to tensile stress. [![enter image description here](https://i.stack.imgur.com/ltEUB.jpg)](https://i.stack.imgur.com/ltEUB.jpg) If you use carbon nanotubes instead of steel to reinforce the bottom side of the beam instead, you can lower the weight of the ceiling for the same surface, thus you will decrease the load on the pillars. This will help you build a taller structure, as you will be able to stack more floors before reaching the load limit of the pillars. ]
[Question] [ I have a super-earth world. The surface of the world is shallower due to extra gravity, so shorter mountain ranges and less ocean depths. The world orbits a binary star system at a distance of the furthest region of the habitable zone, both of the stars having masses of 0.93x that of our suns. The world is highly volcanic, approximately 15 to 16 times more volcanic than our planet. The lithosphere is 4x richer in calcium, magnesium and has much more other minerals than present on earth that is very useful for marine life such as boron and strontium. Surface gravity: 1.35x of Earths. Atmosphere thickness: 10x of Earths (a result of it being highly volcanic in comparison to earth.) Atmospheric composition: Nitrogen 78%, 15% Oxygen, 5% Carbon dioxide, 2% Trace gases. Temperature: rather hot, the tropical regions being 90 to 110 degrees Fahrenheit. (based on what I've tested on Universe Sandbox 2) Land coverage: 75% water, and 25% land (but less water being present on this world as the oceans oceans are shallower mostly due to a lot of island formations) Radius: 7750 kilometers Day/Night length/full rotation: 28 hours. Axial tilt: 53 degrees. Orbital period: 1.15 years Eccentricity: 0.025 --- How could you make it possible for coral reefs to thrive in such a world based on the fact carbon dioxide makes the oceans acidify? [Answer] So, let’s be clear about the ocean acidification problem here: it’s happening **really** fast. As in, we’ve dropped the ocean’s pH by [~.1 pH units in the last 200 years](https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2004JD005220), which is about a 30% increase in H+ ions because logarithms. That’s incredibly fast on both geologic and evolutionary timescales. Corals are dying because they’re having a hard time making calcium carbonate (CaCO3) shells/structures. That’s harder in an acidic environment because calcium carbonate is composed of calcium and carbonate, and there’s less carbonate in an acidic ocean because more of it is in the form of carbonic acid instead. You’ve actually taken the first step toward solving this problem by increasing the calcium reservoir of your planet - that alone will mitigate some effects. However, barring any recent and dramatic atmospheric changes, your corals will *already* be capable of handling the atmosphere. There are some species of coral in the real world that are more acid-resistant, but on an evolutionary timescale they’re spending energy on overly-efficient enzymes to catalyze carbonate precipitation, and are largely outcompeted by less energy-intensive varieties. In your world, however, they’ll already have been selected for and will survive quite happily in the 5% CO2 atmosphere. An especially rainy world might have some additionally helpful effects on the health of corals, but all major influences would be limited to inland seas or areas very close to river inputs. Elsewhere, the solubility pump will work to offgas additional CO2 from the river inputs. [Answer] I can think of two options: If you want to keep lime based coral you need a higher "calcium flux", the calcium cycle on your world needs to be accelerated. This will make more calcium carbonate available to the oceans, some of that will offset the acidity from dissolving carbon dioxide but most of it will be taken up by biological processes. To do this you need to accelerate the carbonate rock cycle of the world. Luckily your atmosphere is already highly acidified due to abundant atmospheric carbon which will dissolve in rainwater to form carbonic acid; that will accelerate chemical erosion of the land and rocks of the continents. To balance that you need more geological activity, uplifting of existing coastlines and reefs above sea level and subduction of calcium rich sediments for volcanic recycling. Alternatively you could change the chemistry a little, [diatoms](https://en.wikipedia.org/wiki/Diatom) are a subset of oceanic plankton that use silica instead of calcium carbonate to make their hard shells, if you were to apply a similar mechanism to coral formation then far from being an issue the acidity of the ocean becomes an advantage as it will mobilise more silicon for biological uptake. Rather than limestone reefs and reef deposits now resemble quartzite. ]
[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/118705/edit). Closed 5 years ago. [Improve this question](/posts/118705/edit) The imaginary country has 5 provinces. The 3 most populous provinces have 10 million inhabitants each and their area is 500 000 square kilometers. The other 2 provinces have 500 000 inhabitants and their area is 1 million square kilometers. It is not possible to redivide the provinces because of geographical and ethnic differences. The first issue is the number of congressmen If we had 1 representative for each 250 000 inhabitants, the densely-inhabited provinces would have 40 representative and the sparse provinces 2. If it were 1 representative for each 1 million, the dense provinces would have 10 and the sparse ones 1. It is weird because, if there were a province of 250 000 inhabitants, a province of 1 490 000 inhabitants and a province of 1 510 000 inhabitants, the first two would have 1 and the third 2. The second issue is to choose between bicameralism or unicameralism A bicameral legislature is slow and rambling, but unicameralism may be bad for provinces that have few representatives. But I have another idea. Instead of having two assemblies, the bicameral system can be simulated with only one assembly. In order to decide something, the decision must pass in two voting criteria. In the first criterion, the vote weight of each representative is the same. In the second criterion, the vote weight of each representative is divided by the number of representatives of their home province and this criterion works like a veto rather than a decision. [Answer] What you're describing is very similar to the [Australian Parliament](https://en.wikipedia.org/wiki/Parliament_of_Australia). Australia has the lowest average population density in the world, but considering most of the inland territories are desert the vast majority of the population lives on the coastline and in fact the two most populous cities in Australia (Sydney, capital of New South Wales and Melbourne, capital of Victoria) account for around 40% of Australia's population. That means that NSW and Vic have a huge representation in our House of Representatives (lower house), and less populous states and territories have proportionally less representation. Our Senate (upper house) on the other hand was specifically designed to even that out. 10x seats per state, 2x seats per territory. The idea of having an upper house in this configuration was deliberately so that the more populous states couldn't override the needs of the less populous ones in the lower house; in theory the other states can override the decisions made on equal representation of the people by providing equal representation of the states. In practice, party based politics override this thinking anyway, and a bicameral parliament is (again, in practice) used by the people as a check and balance at elections, often many vote one party in their electorate, another to the senate so that no side has too much power. This is one of the challenges of a culture that deeply distrusts its politicians, but I digress. Ultimately, there are 3 questions you need to ask yourself about your mythical country; 1) Do your provinces have their own legislative power and do they require their federal counterparts to consider their interests in any way? 2) Is there any fundamental differences in culture, means, or needs of the provincial citizens by comparison to the urban ones? 3) Do your citizenry have any reason (real or perceived) to mistrust their legislature or believe that their powers should in any way be curtailed? If the answer to one or more of these questions is YES, then you need a bicameral system. Not want; need. Ultimately, the provinces won't trust a federal system that tramples over any rights they may have. You also don't want to disenfranchise a provincial minority by constantly voting in urban-centric legislation, as this will sew discontent (and possibly revolt) among those who no longer believe they have a voice. Finally, giving a second chamber to your legislative review ensures that the concerns of the people about checks and balances are at least in part assuaged. Remember that any body that is represented by a body politic will want *equal* representation. For the most part, that means the body of people. In a federal environment, it also means the states (or provinces) and a second house fills that requirement nicely - one house for the people, one for the states. [Answer] To be fair the representatives by number of citizens is basically what a some countries have now, each has a vote equal to others, and obviously it has never caused problems before... Often however, representatives come from 1 per town, soemtimes even a city of 1 million could only have 1 representative at the national level, whereas a city of 50,000 could still have 1. it all depends on how the provinces are laid out. but at the same time, dependent on what part of the timeline this country is currently in, then these towns might be smaller, or they may decide to keep most governmental decisions provincial, and then only the really big stuff is debated on a national level. Your 2 low population provinces sound like agricultural provinces whereas the others seem a lot more built up. and this is similar again to what we have today, how often do you see people that live in country disagree with national decisions made by people in the cities that result in comments like "Such a stupid decision, how would they know what its like out here, they spend all their lives in [London, Washington, Paris, etc]" A Bicameral system would be far better for one but a Unicameral system would be better for the other. the only thing i would say for certain... when has democratic politics ever not been slow and rambling? [Answer] Ultimately this depends on what keeps the electorate happy and convinced that they are being represented. Specifically, to what extent are the folk from populous provinces willing to give the sparse-province folk disproportionately high representation and the sparse-province folk willing to accept that they are an out-voted minority? Personally, if I was a citizen of a populous province and my representative effectively had only a twentieth of the vote of the guy sitting next to her, I would feel pretty disenfranchised. Do you need to have the electoral division based on the provinces at all? It is possible to have the entire country as a single electorate with a multi-seat single transferable vote electoral system. [Answer] Welcome to the electoral college of the US, lol. Joking aside, it sounds like that's the issue at hand. The electoral college, and the system you describe, do result in larger populated areas having more representation. However, it ensures that the larger representation is not oppressively so. While 2 or 3 larger areas could have the same representation of 10 smaller areas, the combined power of all smaller areas equals or outweighs that of the larger. This provides a balance between the needs of the many and the needs of the few. To offset the unequal power of each region, another chamber (the senate in the US) exists with the same number of representatives for each region. So in one chamber of congress, the legislature, parliament, whatever you want to call it, you have population based representation, and in the other you have region based representation. In regards to your world... You can go with unicameralism and choose either of those 2 chambers as the representative body. Whichever you choose will cause conflict among the more densely populated cities and less densely populated outer regions. This could be a good thing for your story line and is something to consider. You can go with bicameralism (your example at the end of a hybrid is still, in essence, bicameralism), which would result in more debate (which could also be a good thing for your story line) but provides less political conflict for your regions. **My Suggestion ->** Let the story line decide. If political discord is a central part of the story, go with unicameralism. If it's not, go with bicameralism. Don't try to force the story line into a preconceived block that may end up causing more plot issues than it solves. More important that deciding which to go with at the moment is ensuring you understand the benefits and drawbacks of both so you can make the right decision for your world when you get to that point in its creation ]
[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. In a world set many years (At least a generation or two) after a near extinction level nuclear event, how could a recovering population set up a internet or internet like service? Key points I'm interested in: Hardware / Software (if applicable) needed Infrastructure needed to be put in place to accommodate. Limitations of this type of internet service (Wired only? Wireless to Xm?) [Answer] ### It only takes a generation or two to build an internet from scratch Think about it: One of the key predecessors of the Internet, [ARPANET](https://en.wikipedia.org/wiki/ARPANET) started in 1969. Look where we are today - or even 20 years ago. It did not take long to go from "nothing" to the Internet as we know it. That was starting with: * Low speed modems * No (or very minimal) networking protocols * No web servers * No FTP servers etc. As I often say, **Knowledge is the Key**. Even if there was **NOTHING** left except the very basics (e.g., even a few old 16-bit computers would be enough to get started) and some determined hackers, it would be possible to start essentially from scratch and build up to full 21st-century level internet in a matter of a few years (guesstimating 1 - 30 depending on the hardware issues). About the only thing that will be **really hard** to do is to create a chip fab. So a key will be salvaged hardware to get through the first few decades. ### Hardware Even assuming that all large equipment on-grid and most cell phones and other wireless devices were "fried" by the apocalypse due to EMP and other effects, there would likely be **some** equipment that survived. It only takes one server with a full [LAMP stack](https://en.wikipedia.org/wiki/LAMP_(software_bundle)) to get things jump-started as far as software. A few computers, routers and other equipment (and really a computer can be a router and a router can be a computer - as with the first days of ARPANET, there is no fundamental difference) salvaged from the rubble somewhere and you have all the hardware you need to get started. DNS and some other pieces will not be so easy. But if you are in a small group then you essentially run as one large local network and, if necessary, hardcoded addresses. Not hard to do with a little bit of surplus equipment. ### Software In addition to hardware, your new Internet will require software. Easiest solution by far is one Linux machine with everything on it. Which is not that unusual. Everything else is copies of copies plus a few hackers that start building useful web sites. No Amazon for a few years - but only because there are no warehouses full of goods and fleets of trucks to deliver them. But basic web sites for social networking, barter & sales, government, etc. can all be done pretty quickly. If you have to start truly from scratch then it still won't take a generation. The simple knowledge that it **CAN** be done, together with some basics of how to do it will lead to a few programmers putting together something resembling a web server in a few years. Very different from 1969 when most of us had no idea what we could accomplish. ### Connectivity There are 4 types of connectivity involved. Each has advantages/disadvantages: * Wired Wired connections (e.g., 100 Meg. or 1 Gig. copper) are the easiest. Salvage some cable (every destroyed building is filled with it) and you can put together a network 100 meters at a time very easily. Longer connections are a little tougher because you can't order a line-driver/extender on Amazon, though a few years of work and that can get resolved too. But in the short term, start with a basic 100 Meg. network and you can extend it around town using every switch and router you find. * WiFi WiFi is also pretty easy. Get a few salvaged access points running and you're all set. Actually, WiFi will probably work better than it does now because, initially at least, there won't be any interference! But WiFi is range-limited, and again you won't be able to easily get top-quality longer-range access points for a few years. * Fiber Fiber is the best. But unless you can find a good cache of cable and top-quality tools, fiber will take longer to get online than copper. You can't just splice together bits & pieces the way you can with copper. * Cellular and other long-range wireless This will be the hard one to do. The cell phone network was destroyed in the apocalypse, and even if you can find an occasional functional cell, it is useless without the infrastructure which depends on the phone company's demolished data center. So connectivity will be limited to wires and WiFi for a few years. ### Power Last, but not least, is power. None of this will work without a reliable power source. But everything else in modern civilization needs power too, so that will be one of the top priorities (along with food) for the survivors. Once they have reliable power, the Internet will be easy. While powering the internet will be a lower priority than powering lighting, machinery in factories and many other things, the basic internet will not require much power - a few hundred watts here & there. You won't have big data centers, with their big power requirements, for a while. [Answer] There are three components to a successful social communication via technical methods: * Availability of hardware; * Availability and ease-of-use of software; * Infrastructure viability and reliability. I am "porting" a somewhat famous statement of Vitus Wagner that hard-SciFi space travellers would use [UUCP](https://en.wikipedia.org/wiki/UUCP). Because TCP would time-out and, well, who uses a packet protocol on a network with hundreds of seconds ping? # UUCP is post-apocalypse Twitter The post-apocalyptic cyberpunk bands would use UUCP. Either they'd have some specialists from pre-fall era that would correctly identify the best method and provide for it. Or they would build something on their own, similar to the amateur networks such as [Fido](https://en.wikipedia.org/wiki/FidoNet) and the likes. So, the future internet of post-apocalypse (in my vision) is much more [NNTP](https://en.wikipedia.org/wiki/Network_News_Transfer_Protocol) and much less Twitter. 1. You need a server for HTTP and the likes. Servers need permanent connection, even worse: they need to be protected and supplied with electricity 24/7. 2. A distributed infrastructure can crawl from one device to next in a relay manner. No permanent activity or availability is needed. 3. UUCP and NNTP are **old**. This requires some ingenuity to even think about them in this context, sure. But these are *proven*, trusty solutions that worked well when the computers had much less power and resources. This fits post-apocalypse well. 4. Even if the *exact* the same protocols are buried in the unholy depth of RFCs no one have read and the pre-apocalypse script kiddies are inventing their own bicycle – similar circumstances produce similar solutions. FidoNet was uglier and sort of more convolute than NNTP, but they both function in a similar manner and yield similar results. And a similar culture, by the way. --- So, we have allied gangs and small groups that send messages to each other via some kind of an ad-hoc network. The delivery is not instant, but very reliable. No central infrastructure is needed. Strong (and *strange*) relationships of trust and communication hierarchy ensue. Sounds like the cyberpunk we do deserve. [Answer] # Forget wires, get a cell tower running and use mobile data. If you can get a tower running, with a surviving technician's help, or by reading the manuals, you could reset its systems and tell it that you're its new owner. You could be your own phone company. Whatever surviving phones you find in the region will mostly all be compatible with that region's tower. You might think that 4G is a ridiculous way to share all data, but that's just because human population density is currently straining the tower's maximum bandwidth, and existing phone companies are throttling 4G and making it expensive. Your phone can actually transfer plenty of data very quickly over 4G connections, it's just that the tower is over-burdened and talking to your phone slowly these days. With most humans gone, and almost none of them having working phones, that tower will have bandwidth for miles. You'll finally be able to transfer data over 4G at the maximum rate your phone is capable of, which is pretty high for modern smartphones. One mobile-hotspot could provide for a post-apocalyptic village. And as the new owner of a cell-tower, you can give your people some very favorable mobile-data plans. Finally, additional data fees will *not* apply. [Answer] Ad hoc wireless networks seem like the correct networking strategy here! There are dozens of designs out there, with various pros and cons, and they can be built with a wide range of wireless underlying technologies.<https://en.wikipedia.org/wiki/Wireless_ad_hoc_network> is a good starting point. Note that "wireless" is often mistaken for meaning "Wifi", and they're really not at all the same; different frequencies of radio waves have different properties. I'm not a radio geek so can't say too much more than "you can get some wireless technologies with crazy range". Keep in mind also that a network can be built with different parts using different technologies; so a lot of low-power wifi nodes can link to a high-powered central node that connects over cable, satellite, high-powered radio waves that can travel long distances to other such nodes... take your pick. The question of hardware and software is a trickier one. @manassehkatz' answer above about scrounging the existing stuff and building from there is a good one. I'd emphasize if you're really dealing with a wipeout scenario that the processors are going to be your biggest issue. Chip fabrication is *hard* and requires a lot of prerequisite technology (and some *very* interesting chemicals and some rare minerals) to implement, and very few people actually really understand everything involved; chip design is a specialized field, and even there, the people working on instruction sets and security features aren't likely to spend much time on the physical chip layout, let alone on the actual fabrication process. And the materials scientists dealing with fabrication are likely to know nothing about the functionality in an x86 architecture. I'd expect the first several generations of post-apocalyptic computing to be very bulky and slow as a result-- you can create 1980s-level processors with some basic electronic components in a garage without much trouble, and I *think* the components aren't too hard to manufacture (though i'm not confident), but the smaller and more unified and more powerful they get, the more you go from "need to have power" to "need to have mines, and chemical factories, and skilled workers, and sterile environments with specialized HVAC, and expert processor designers, and..." You will save a lot of the time we as a society took in the development of the computing technology because we can reconstruct and learn from past experience-- especially if anyone has a good library available with high-quality textbooks and manuals-- but you can't get around the industrial base required to build the physical objects, or the complexity of those designs. There's a reason Intel and Apple have thousands of people on the job. [Answer] So assuming that some technology still works, and you have proper geeks and greybeards to run it all, there are plenty of options. First - that which exists already. [IP over ham radio](https://www.ampr.org/). The entire 44.0.0.0/8 network was designated for this purpose when IANA first started allocating hunks of IP space. Not the worlds best and some confusion on what you can do with it now (due to FCC rules) but there are active networks using it. [IP over avian carrier](https://www.rfc-editor.org/rfc/rfc1149). Yes, carrier pigeons. RFC1149 was originally a joke, but it has been implemented several times and has actually been proven to be [faster on data delivery than the DSL provided by one South African service provider](http://news.bbc.co.uk/2/hi/africa/8248056.stm). Other ways. Plain old 802.lla/b/g/n can be sent LONG distances with proper antenna at both ends. Get some elevation involved and not a lot of trees, etc. and you can shoot a signal for miles and miles and miles. The issue will be initial set up of routing but setting up a tower chain like [Terry Pratchett's Clacks Network on the Discworld](http://discworld.wikia.com/wiki/Clacks) would be trivial to do with early 2000 computing equipment. There are lots different medium that you can communicate over in IP packets - such a [plan or possibility is included in the OSI model - physical layer can be anything!](https://www.networkworld.com/article/3239677/lan-wan/the-osi-model-explained-how-to-understand-and-remember-the-7-layer-network-model.html) Once you have that, then what language do you speak over the packets? Well, you are looking at low bandwidth stuff. Where possibly everyone is a producer as well as a consumer of content again. So go back to the old protocols. You can [finger](https://arstechnica.com/civis/viewtopic.php?f=16&t=38937) the next clan over to see if there is a BBQ planned, you can email via smtp or UUCP, you can get web pages or other files via http,etc. [Answer] I don't think it would realistically work as a legitimate internet service. I personally think it would have to be a sort of local network. Let's take for example, something like Microsoft Excel. If a group of people were responsible for inputting data, the other might be able to link to the computer. They would have to find a way to connect all devices together like a huge super computer with users that have certain access. I imagine, the system is pretty much in one spot like a library and there are multiple terminals all ultimately plugged into each other. Certain people may be known as scribes and have access to input information into the database. Others would be regular users and only be able to read the data rather than edit it. ]
[Question] [ In the future, *Big Business* owns the government. Corporations such as Target, Walmart, General Motors, etc... now have a major hand in deciding policies in the country. This has a major impact on how workers are viewed by their companies. A law called SEDWA (*S*hameless *E*xploitation of *D*ead *W*orkers *A*ct) has passed, which most big companies have taken advantage of. An employer has the right to resurrect a person after death for continued service to that company. This is part of the contract that this soon-to-be corpse, better known as an "employee", signs when hired. When a worker dies after a lifetime of being nickled and dimed, their body is resurrected for further servitude to the company and put back to work. This ensures that the corporation gets the full mileage out of their workers. The process has been active for several decades, and the Zombie work force is a common sight in many kinds of jobs. This resurrection process is not cheap, so only big corporations can justify the expense. These zombies cannot follow complex commands and are relegated to performing unskilled labor. However, they are the perfect example of what a good employee should be. They don't eat co-workers, are obedient, are able to work 24/7, don't bitch and moan about work safety or ask for pay, and are cheap to maintain due to not being affected by decomposition. Even better, they don't violate the fair labor standards act set in place by those annoying and ridiculous labor unions, which demand a minimum wage and 40 hr working weeks on account of the person already being dead. It's a win-win from the employers perspective! The problem I have here is that I don't know if the process of resurrecting these workers and binding them to eternal servitude would be worth it to the employer in terms of cost effectiveness. What estimates do I need to take into account to make this plan marketable to corporations? Is it economically viable? [Answer] The big question will be how long it'll take governments to extend human rights to the dead. Everyone's comparing these creatures to robots, and it's a fair comparison, but it'll be way easy to humanize (or perhaps re-humanize) them in the eyes of the public. Get pictures of a few, let people know their names, or what their names were), trot out their families, what have you. In no time you'll see a groundswell of public opinion against the idea. Politicians will demand the process stop, and since the corporations will have certainly gotten the dead bodies declared property, or something, hastily (and almost certainly poorly) crafted legislation will get them declared human, and as such, getting coverage to what little worker protections are left in this horrific future era. [Answer] Zombies as you describe them are a form of artificial worker. We already employ a great number of artificial workers in some industries, except they aren't undead. They're robots. Robots are a good analogue for what you're trying to describe; high initial investment, low level of specific skill which makes them ideal for specific repetitive tasks, and far lower maintenance costs overall. Additionally, they don't get paid, join unions, etc. So where does it make sense to use robots? Largely on assembly lines at present, but even that's changing. Like your zombies, they don't have high cognitive abilities and while you can say that they are great at 'unskilled' roles, there are less and less of those available in the workplace because of robots' poor cousins - machines. Where 50 men used to go into a cane field and cut down sugar cane with machetes, now 1 person drives a harvester through the field and harvests the cane far more consistently, and faster. Ultimately, the workforce is shifting to a smaller number of highly skilled workers because of mechanization, and zombies would fill a niche that is quickly disappearing from our economy. Autonomous robots are also getting smarter (like drones) and are taking over even some semi-skilled roles. The advent of self-driving cars (for example) is going to replace even semi-skilled labour like taxi drivers, so eventually even the cognitive limits of zombies would be replaceable, and when that happens the cost for what is, in essence, a biological robot with limited programming capability will be in direct competition with that of robot manufacture. This means that your value proposition for zombies is tied thusly; 1) Can Zombies do the work? 2) Can Robots do the work? 3) If Yes to Both, which is Cheaper? Cheaper needs to be explained more completely; cheaper in a Total Cost of Ownership (TCO) context means factoring in initial purchase cost, maintenance costs over the 'lifetime' of the asset and then the assets' mean time to failure (to figure out when you need to begin the cycle again and purchase replacement assets). Ultimately, robots are likely to beat zombies every time in this space, and the cost of manufacture is constantly going down, as the capabilities are constantly going up. I can't see the same capability curve being achieved through zombieism. [Answer] If you changed the word undead to robot and then looked at the modern world, you'd have your answer. There is functionally no real difference between a robot and a zombie. You have a large upfront cost which is offset by increased production and no wages and other employment expenses. You still need skilled employees for complex thinking tasks but dull repetitive tasks, you no longer need to employ humans. Your answer is obviously yes if the cost of reanimation was less than the cost of employment. The only real question is how MacDonalds can get zombies food safe accredited..... [Answer] Assuming that a given industry *can* use zombie labour, I'd expect that the childcare industry, for example, would be more than a little hesitant, to say the least, to employ the undead, they'd have to run the following equation: Average life-span of an undead servitor x minimum wages for a living employee - cost of resurrection. If the result is a positive number then you're making a profit on your zombies compared to your living workers and they're worth having. ]
[Question] [ Okay, so I was creating a cold-blooded humanoid species (for a story, I'm no scientist) and ran into a problem with some of my logic. Because of their obvious issues with overheating, these lizardmen couldn't be pursuit predators like humans proper can with their miraculous ability to sweat. So I adapted them for ambush tactics instead. After all, because they don't waste nearly as much energy with homeostatic systems, they could wait around until prey showed up instead of having to hunt it down like a common mammal. With this in mind, I decided to utilize the broad bodies I gave them for sunning themselves to make them really good at throwing weapons. After all, javelins and throwing clubs are a great way to kill prey without putting yourself at risk. Plus, it would give the species a much needed edge in combat against the superior stamina and environmental resilience of humans (and I think throwing weapons are cool). So here was my logic: *Broad shoulders*, *long arms*, and *very elastic tenons* were supposed to give this species the ability to throw objects at greater velocities than humans ever could due to leverage. Seemed open and shut at the time. However, I was watching [this video](https://www.youtube.com/watch?v=ImYu9dJM4kQ) by the god-amoungst-men Zootier and he pointed out that the qualities I assumed would give them an advantage would actually make them worse at throwing things. In short, it's short arms and superior balance that allows humans to make fifty yard passes while other apes can barely qualify for a softball team. The long arms and broad torsos of my humanoid reptiles just seem to make them more prone to falling over whenever they put their weight behind their pitches. **If my logic is flawed (which it seems it is), what changes do I make to make these creatures capable of throwing objects at greater velocities than humans?** In case it is relevant, their accuracy isn't intrinsically better than a humans, but these reptiles tend to practice a lot to make the most of their fastball advantage. [Answer] Accelerating anything means using force on it, for a period of time. More muscles, more force, case closed? No. * Muscles do not magically produce force, it is biochemical reactions that do the -pun intended- heavy lifting. These limit the maximal contraction-velocity. * This is where levers and other kinds of force/way exchanges come into play - you have the slow muscle go way x with force F (at ideal velocity) then some other point P goes way x\*n with Force F/n. If that happens in the same time, P will be faster by factor n. * You just need to make sure to supply enough Force so that F/n is still enough to actually acelerate the mass at point P to that velocity. * Elasticity in the system can be bad or good, depending on the specifics of the design. For instance an elastic element like a bow enables us to slowly but with high Force draw, and then release in an instant. This is also possible in-body. On the other hand a too-elastic sinew will 'eat' all the force, and might not release it until the missile has already left the hand. So your long-armed reptiles may be better or worse at throwing, **but the best- designed long arm will always be better than the best-designed short arm** - All of the above factors like sinew elasticity, best muscle contraction velocity/force combination, leverage etc. have to be exactly right and are interdependent **and** their efficacy is dependent on factors like missile weight, throwing angle, accuracy, etc. That's why some people suck at throwing, even if they train. Maybe most of your lizard folk can hurl a 10kg uber-spear into 100m distant targets like a meteor, but at the same time suck at softball. Addition : There even is a phd written on that very subject (well, not lizard-folk) - possibly more than one, but i found an accessible one: Julia Marie Maki, "[The Biomechanics of Spear Throwing: An Analysis of the Effects of Anatomical Variation [...]](https://openscholarship.wustl.edu/cgi/viewcontent.cgi?article=2044&context=etd)" - it is 300+ pages, but a few insights are shared on the first few that i skimmed: * Spear throwing **is not equal** to ball throwing (elbows are out of the picture for spears). * Spear throwing has many factors, but reliable predictors are torso- and leg-anatomy. * Broad shoulders are *beneficial* for Spear throwing. [Answer] Tools can make them capable of achieving that, without changing their bodies. Let's start with a simple example: throwing a ball. If you use your hand and arm, you can throw it to a certain distance. Now, use something like this [![ball thrower](https://i.stack.imgur.com/PN0OR.jpg)](https://i.stack.imgur.com/PN0OR.jpg) and you will be able to launch the ball farther and faster. With some modification you can use a similar tool to launch a spear. This tools was also used by our ancestors, and is called [atlatl](http://waa.basketmakeratlatl.com/?page_id=177) > > An atlatl is essentially a stick with a handle on one end and a hook or socket that engages a light spear or “dart” on the other. The flipping motion of the atlatl propels a light spear much faster and farther than it could be thrown by hand alone. > > > [Answer] Throwing is not about the length of the arm but about how the shoulder is structured, a chimp is incapable of the the full rotation an arm goes through during an overhand throw. Basically if your lizardmen can put their shoulder through a full 360 rotation then they can throw. This feature only evolved in humans [recently](https://www.nature.com/articles/nature12267.epdf?referrer_access_token=RahRkeWmny3XcJ5yA58vwdRgN0jAjWel9jnR3ZoTv0PrL_OOAf0hCnPhjqYyzx_-28HKy2gSKei1zr-r7emL6I2NInrPWsv35IW9AKti8gRx-y9o_L5b2P9dz0sSfB2ogjKKMcAZzOjvKQ1hOrRmrT9Ru5KB46GKQQN3WEGhlQxpB-rj1fyLsBG9Yt3IipU2MmhlbyJzYF9AUrZwX3hGgZTVx3mXFfw92c5YlNs20lGYb-8EQ5L52fhCnYLlf1G_8pfR7qlIufQ2QI148Qvb4f4kUrAKDacTlzO5LWxOTT0%3D&tracking_referrer=articles.latimes.com) once climbing was no longer important. the anatomical needs for throwing is actually well studied. the hard part is making them better than humans who are the best throwers in existence.you might want to consider if the tail could contribute somehow, maybe as a cantilever. If your really need an advantage over humans pebbled scaly skin will function like armor which will be a noticeable advantage. [Answer] If you want to get really creative, why not give them the sort of biological spring mechanism [mantis shrimp](https://en.wikipedia.org/wiki/Mantis_shrimp#Claws) use to break open clam shells (accelerating their limbs at over 100,000m/s and striking with enough force to cavitate the water around the strike which produces a measurable aftershock). Have a look into it. They're mindblowingly powerful. You'd need some pretty advanced musculature around them to bring finesse and accuracy to such an adaptation, but if you could then you'd have a significant range and power advantage against a human missile-thrower. Whatsmore, you'd also pack a fearsome punch in a close quarters fight (although likely at the cost of endurance/frequency of repeat strikes). It'd make for some pretty interesting combat dynamics between humans and your biological-catapult lizardpeople. I'd expect the lizardperson try to hold off until it can best use its advantage? Would a human try to provoke the lizardperson to strike multiple times, tiring it, or try their best to dodge the initial ferocious strike and then strike back before they can recover? ]
[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 3 years ago. [Improve this question](/posts/115769/edit) I’m writing a [Splatoon](https://en.wikipedia.org/wiki/Splatoon) fanfic, and I was hoping to make it a bit more science-based than the minuscule information we’re provided in-game. The two primary features of [Inklings](http://splatoon.wikia.com/wiki/Inklings) are their ability to shoot ink and refill by diving into their ink, as well as their ability to switch between squid and kid. For the former, we are given much more information: * Instead of a heart pumping blood like us humans, Inklings’ hearts pump ink. * Somehow some of this ink can be transferred into a pack strapped to their back, which powers a plethora of splatting weapons. * By submerging themselves in ink, the Inklings can refill their tanks. This seems to work through something like diffusion. The problem comes with the kid-squid transformation. Somehow they can switch near-instantly between a smallish squid-like form and the normal-sized humanoid form. In squid form, they are able to swim quickly in their own color of ink, move through metal grates, and fly to a different place on the map. Their clothing and weaponry are also preserved during transformations: they don’t wear them while they’re a squid but do while they’re a kid. The games strongly imply that there’s no magic in this universe, so handwavium shapeshifting isn’t an option. The last feature is that when killed, their body explodes into ink, and their “spirit” returns to their team’s spawn point, where a replica of their original body is recreated, and their spirit is placed into that body. The questions I have are: * How would you go about designing a creature that can transform between a squid with these properties to a kid with these properties? * How would a squid be able to do things like moving through metal grates and launch itself in a parabolic arc across the map? [Answer] **Point 1: The ink is alive** The "ink" is actually a form of colonial microbe. This microbe is capable of forming a biofilm-like network with microscopic muscular and neural structures. The battle between inklings is actually a conflict between different "ink colonies". **Point 2: An Inkling body is basically a suit that the ink can use to move in a coordinated manner** An Inkling's "kid" form, while superficially human, is anatomically nothing like humans. It is an environmental suit - perhaps artificial, perhaps a living symbiote - for the microbe swarm. It is controlled using an ink-based hydrostatic skeleton. When "transforming", it basically *turns inside out* - expelling the ink that supports its body and covering its deflated shell with a layer of microbes, creating the "squid" form. It is able to move much faster in this form while within its own colony - the surrounding ink creates a peristalsis-like muscular motion to shove the "suit" along. The "kid" form is used when the microbes need to travel outside of their biofilm. [Answer] There is no 'human' form - its an illusion / a disguise of the squid-like inkling. The squid can increase its size (maybe it sucks in air, so this only works on land) and has very fine control over how and where these changes happen in its body, so it can change its form to that of a human kid. Basically this is like a 3D/shape version of colour-changing skills that some squids/octopuses have. (Of course, it also needs the color-changing skin to simulate clothing and the whole appearance thing). In the squid-form the Inklings don't need to put any energy into maintaining this disguise. This allows them to use their 'ballooning' and fine control over the body to generate a strong (albeit short) tension in their body, which can be used to fling them whereever they want to go. As for moving moving through objects: squids are good at that - they're about as liquid as cats (it doesn't work the 'human' form since upholding that requires a sort of tension in the whole body). ]
[Question] [ So, out in Den, Colorado, the slave trade is absolutely booming. Slaves from nearby tribal villages and towns like Boulder and Five Families are always coming in and out, and honorable entrepreneurs have decided to start working in this business. To protect slavers from harsh treatment by local villages, a Slavers Union has formed. But, the SU needs an HQ, and they are too lazy to build one themselves. So they decide to use one of the pre-war buildings, but it has to fit these criteria. 1. Must have infrastructure capable of keeping people restrained and stop them from escaping. 2. Must have the ability to survive for about 5 decades unmaintained. 3. Must be easy to protect, with good defenses to stop unwanted people or creatures from getting in. [Answer] I currently work in corrections. The Denver Jail would suffice. Jails that are decades old are often still in use today. A county lockup nearby where I live was built in the 60's, aside from the occasional new coat of paint and some new doors installed it is still in full use housing about 50 inmates. Jails are already built like fortresses, and wouldn't be looted since jails contain very little in the way of anything valuable, and are also pretty hard to get into. Best part, the entire layout and infrastructure of the building is totally designed for holding unwilling captives and deterring nosy outsiders. I suggest the Denver department of corrections prison building. Its big enough to hold all the merchandise but also fortress-like enough for your aspiring indentured servitude merchants to protect themselves and their profits. A prison after the apocalypse would basically be a free castle for whomever has the manpower and gumption to take it and use it as such. [![enter image description here](https://i.stack.imgur.com/qaX1o.jpg)](https://i.stack.imgur.com/qaX1o.jpg) [Answer] While the jail may be the best choice, there is a possibility that either the Duke of Denver isn't willing to give it up as his fortress, or it was destroyed or partially destroyed in the Apocalypse. There are some other possibilities that come to mind. The most likely is to find a records repository. These buildings are fortresslike by design, and house the records of governments or corporations. Insurance companies, in particular, have or at least had massive repositories for their records and contract paperwork. The building may have few windows or doors, was originally climate controlled, and built out of concrete in order to be fireproof or at least fire resistant, which gives it a good possibility of surviving many types of apocalypse. New residents will need to get rid of all the paper inside. The Colorado State Archives in Denver is located at 1313 Sherman St, Denver CO 80203. Another structure which is likely to be overlooked is old telephone switch exchanges. They were built to house the electromechanical relays for the old rotary dial phones (the series of clicks you hear when dealing a rotary phone was these switching elements turning into place). Large urban centres like Denver would have had large buildings devoted to this purpose, and they would also be strongly built both to protect the equipment, provide a stable base for the machinery, and house the climate control equipment and things like emergency generators. Modern phone switching is done by computer, which takes much less space, but you can often see these mostly empty buildings still in use, with the racks of old switches long removed. [The Telephone Building](https://coloradoencyclopedia.org/article/telephone-building) at 931 14th Street in Denver is a likely candidate. [![enter image description here](https://i.stack.imgur.com/02Emj.jpg)](https://i.stack.imgur.com/02Emj.jpg) *A bank of two motion switches. A telephone switch exchange could have huge racks of these filling the building* [![enter image description here](https://i.stack.imgur.com/gA60d.jpg)](https://i.stack.imgur.com/gA60d.jpg) *The Telephone Building* Finally, and more speculatively is the [tunnel complex](http://www.strangehistory.org/cms/index.php/popular/77-denver-international-airport-conspiracy-denver-colorado-feature) under the Denver airport. Dug during the construction to house the various services and especially the complex (and ultimately unsuccessful) baggage handling system. Although there are plenty of people who believe the tunnels are used to house other things, including the secret headquarters of the New World Order, after the apocalypse the most likely issue with using the tunnels is they will be filled with vermin, mould or perhaps flooded. Any surviving members of the New World Order likely escaped the apocalypse with Elon Musk and now live in tunnels under Olympus Mons on Mars.... [Answer] **Cheyenne Mountain Complex** <https://en.wikipedia.org/wiki/Cheyenne_Mountain_Complex> [![Cheyenne mountain complex inside](https://i.stack.imgur.com/HAwqo.jpg)](https://i.stack.imgur.com/HAwqo.jpg) <https://www.inquisitr.com/1994796/cheyenne-mountain-complex-to-re-open-prompting-emp-attack-and-world-war-3-fears/> [![Cheyenne mountain complex from the air](https://i.stack.imgur.com/D4mss.jpg)](https://i.stack.imgur.com/D4mss.jpg) <http://www.norad.mil/About-NORAD/Cheyenne-Mountain-Air-Force-Station/> This is an extreme superfort; a giant subterranean bunker and command center deep enough to survive nuclear attacks. It has its own water. It is about an hour south of modern Denver, outside Colorado Springs. As far as a slaver castle, one could use the entirety of the subterranean component for slave pens and use the above ground pieces as defensive works. The setup with the mountain road as the only approach reminds me of medieval castles. Good luck with any frontal assault on Cheyenne Mountain. ]
[Question] [ I am in pursuit of, as the title says, a multi-purpose horse, a single breed that can do all the things that the others were only specialized for: travel, labor, companionship, war, speed, strength. If dog-breeding is any indication, it's that finding the right mix takes some steps. So we start this journey with two fairly similar breeds of horse adapted to the same basic climate: [![enter image description here](https://i.stack.imgur.com/2iBxQ.jpg)](https://i.stack.imgur.com/2iBxQ.jpg) The Icelandic horse [![enter image description here](https://i.stack.imgur.com/rfZhJ.jpg)](https://i.stack.imgur.com/rfZhJ.jpg) The Yakutian horse of Siberia Why am I breeding two similar breeds living in similar conditions? Because each breed has its own characteristics. The Yakutians have to deal with life in Siberia, which can range from 100 degrees Fahrenheit in the summer to 90 below in the winter. 1. A dense coat, obviously 2. Antifreezing compounds in the blood 3. Their metabolism adjusts to seasonal needs. In fall they accumulate large fat reserves, in winter the metabolic rate is lowered, and in spring they show an increased carbohydrate metabolism, making use of the freshly sprouting grass. 4. They may further avoid frostbite by reducing the volume of circulating blood during times of extreme cold The Icelandic horse has its own characteristic--an extra gait more energy-saving and comfortable than the other four (gallop, canter, walk, trot). This ambling gait made the Icelandic horse a popular breed for use by Middle Age travelers. ***So by breeding Icelandics and Yakutians together, I have made a small but strong horse able to both withstand every environmental extreme and amble comfortably over long distances. True or false?*** [Answer] I don't have a professional history in horse-breeding, but I do know a thing or two about genetics. I believe that if you specifically selected horses of both breeds that had those traits in the highest abundance, then you could end up with a horse good at both of those things. I read up a bit on both breeds, and it appears that some Icelandic horses prefer to trot rather than amble. Obviously, you wouldn't breed these horses with the Yakutians if you wanted your new horse to amble. [![enter image description here](https://i.stack.imgur.com/4Cx2Z.jpg)](https://i.stack.imgur.com/4Cx2Z.jpg) *Icelandic horse gaits. Left to right: walk, trot, canter, amble, gallop* Similarly, you would want to breed your ambling Icelandics with only specific types of Yakutians. I assume that the Northern subtype (Shown below) is best at blood coagulation and other cold-climate adaptations since they live in harsher conditions, so those would be the ones you want. [![enter image description here](https://i.stack.imgur.com/BTNpV.jpg)](https://i.stack.imgur.com/BTNpV.jpg) After dozens of breedings, I believe that your new horse would have the abilities to withstand extreme climates like a Yakutian and amble like an Icelandic. [Answer] Short answer: genetics is a crap-shoot but you are starting from a good place. Considering the mind-boggling number of genes and gene-complexes that may go into making up the traits you're looking for you can't use a single breeding event, and you wouldn't get a new strain event if you got one foal that was perfect anyway. You may indeed be able to use these two breeds to create a new horse strain that has the desired characteristics but you're going to need large number of both primary breeds and you're going to have to breed, cross-breed, and back-breed them until you get the mix right in enough cases to create a stable herd that "breeds true" AKA all pairings within the herd consistently produce the desired traits and continue to do so for several generations without unacceptable levels of mortality or "throwbacks" creeping in. Don't ask me what an acceptable, or unacceptable, level is I'm not a pedigree breeder of any stripe. ]
[Question] [ It’s the year 2568, exactly 500 years after Nuclear war destroyed the two superpowers that started it, the United States and the Soviet Union, along with others such as China, both Koreas, Japan, France, The UK, India, and the Middle East. What American monuments that weren’t hit directly by the bombs could survive 500 years without any repair? * By "weren't hit directly" I mean, assuming no monument was destroyed during the nuclear war, and given the post-apocalyptic conditions, which monuments would stand the test of time? * I am interested in man-made landmarks such as Mount Rushmore and Hoover Dam. [Answer] # [Mount Rushmore](https://en.wikipedia.org/wiki/Mount_Rushmore) Albeit with some erosion. To imagine the result of 500 years of lack of maintenance, take a picture of the current state of Mount Rushmore and apply a mild Gaussian blur filter. We are talking about four gigantic faces carved in stone on the side of a mountain in a region that is not densely populated, filled with wildlife, far from industrial complexes (e.g. acid rains are unlikely), and surrounded by woodland, prairies, and badlands. Interesting part, behind one of the faces there should be a room carved inside the mountain and filled with documents. It could probably be used for something else too. # The rest ## Dams Dams require constant attention. In 500 years there may be but a slight memory of it from some pieces of concrete attached to the sides of the mountain. The water will break through and erode its way across. A lucky dam will crack at the bottom and remain as an archway across a river. I doubt that is likely to happen, but if it does, here is [a list of the tallest dams in the US](https://en.wikipedia.org/wiki/List_of_tallest_dams_in_the_United_States). **A note about gravity dams**. As suggested by [Andon in the comments](https://worldbuilding.stackexchange.com/questions/104536/what-man-made-monuments-in-the-u-s-could-last-for-500-years#comment315654_104539), gravity dams may be less prone to failures and thus longer lasting, perhaps even for the timescale of the question. ## Skyscrapers Skyscrapers are marvels of engineering, but they too require constant maintenance. Not much will survive 500 years due to the elements, corrosion of the internal supporting structure, and pillaging of construction materials. At best, the foundations of these tall buildings may remain as a sign of their greatness. ## Metal-made constructions Bridges (Golden Gate), signs (Hollywood sign) or statues (e.g. Liberty Statue). These too require constant maintenance. Today the main threat is due to rusting and corrosion. In 500 years without a stable social structure, these constructions will be the number one source of free high-grade metals. Not much may be left, except perhaps the pedestals. ## Other monuments and memorials A quick look at the rest, taken from a subset of two wikipedia lists: [National Monuments](https://en.wikipedia.org/wiki/List_of_National_Monuments_of_the_United_States), [National Memorials](https://en.wikipedia.org/wiki/List_of_National_Memorials_of_the_United_States) 1. High chance of surviving monuments, given that they already survived a long time on their own without proper maintenance (e.g. ancient precolombian dwellings); also, their being further away from bigger cities may spare them from pillaging or being used a quarries for construction materials; some could likely be buried under some meters of soil brought by rainwater, wind or partially damaged by minor land slides: [Agua Fria](https://en.wikipedia.org/wiki/Agua_Fria_National_Monument), [Aztec Ruins](https://en.wikipedia.org/wiki/Aztec_Ruins_National_Monument), [Bandelier](https://en.wikipedia.org/wiki/Bandelier_National_Monument), [Bear Ears](https://en.wikipedia.org/wiki/Bears_Ears_National_Monument), [Chimney Rock](https://en.wikipedia.org/wiki/Chimney_Rock_National_Monument), [Fort Union](https://en.wikipedia.org/wiki/Fort_Union_National_Monument)(not really in working order), [Hovenweep](https://en.wikipedia.org/wiki/Hovenweep_National_Monument), [Little Bighorn Battlefield Monument](https://en.wikipedia.org/wiki/Little_Bighorn_Battlefield_National_Monument), [Navajo](https://en.wikipedia.org/wiki/Navajo_National_Monument), [Poverty Point](https://en.wikipedia.org/wiki/Poverty_Point_National_Monument), [Tuzigoot](https://en.wikipedia.org/wiki/Tuzigoot_National_Monument), [Wupatki](https://en.wikipedia.org/wiki/Wupatki_National_Monument), [Fort Caroline](https://en.wikipedia.org/wiki/Fort_Caroline) 2. Probably still existing, at least in part, but being a good standing castle, or a defensive structure, possibly with thick stone walls stone, it might be used in between as a defensive structure and suffer significant damage; also, not negligible chances of the structure being completely demolished during some skirmish, especially near bigger cities: [Castillo de San Marcos](https://en.wikipedia.org/wiki/Castillo_de_San_Marcos), [Clinton Castle](https://en.wikipedia.org/wiki/Castle_Clinton), [Fort Frederica](https://en.wikipedia.org/wiki/Fort_Frederica_National_Monument), [Fort Matanzas](https://en.wikipedia.org/wiki/Fort_Matanzas_National_Monument), [Fort McHenry](https://en.wikipedia.org/wiki/Fort_McHenry), [Fort Monroe](https://en.wikipedia.org/wiki/Fort_Monroe), [Fort Pulaski](https://en.wikipedia.org/wiki/Fort_Pulaski_National_Monument), [Fort Stanwix](https://en.wikipedia.org/wiki/Fort_Stanwix), [Fort Sumfer](https://en.wikipedia.org/wiki/Fort_Sumter_National_Monument), [Governors Island](https://en.wikipedia.org/wiki/Governors_Island_National_Monument), [Montezuma Castle](https://en.wikipedia.org/wiki/Montezuma_Castle_National_Monument), [Salinas Pueblo](https://en.wikipedia.org/wiki/Salinas_Pueblo_Missions_National_Monument), [Chamizal](https://en.wikipedia.org/wiki/Chamizal_National_Memorial), [Lincoln Memorial](https://en.wikipedia.org/wiki/Lincoln_Memorial), [Jefferson Memorial](https://en.wikipedia.org/wiki/Jefferson_Memorial), 3. Probably still existing, but less likely to be accessible due to natural problems, such as earthquakes collapsing caves, or floods placing the grounds underwater; if no such events occur, then the monument should still be there as it has existed already for quite some time without maintenance: [Glia Cliff Dwellings](https://en.wikipedia.org/wiki/Gila_Cliff_Dwellings_National_Monument), [Ocmulgee](https://en.wikipedia.org/wiki/Ocmulgee_National_Monument), [Russell Cave](https://en.wikipedia.org/wiki/Russell_Cave_National_Monument) 4. Very unlikely despite being robust and sound structures, mostly due to location, accessibility as quarries, and not easily defendable unless major masonry work is undertaken: [Lee Memorial](https://en.wikipedia.org/wiki/Arlington_House,_The_Robert_E._Lee_Memorial), [Federal Hall](https://en.wikipedia.org/wiki/Federal_Hall), [Grant's Tomb](https://en.wikipedia.org/wiki/Grant%27s_Tomb), [Korean War Memorial](https://en.wikipedia.org/wiki/Korean_War_Veterans_Memorial), [Martin Luther King Memorial](https://en.wikipedia.org/wiki/Martin_Luther_King_Jr._Memorial), [Perry's Victory Memorial](https://en.wikipedia.org/wiki/Perry%27s_Victory_and_International_Peace_Memorial), [Vietnam Veterans Memorial](https://en.wikipedia.org/wiki/Vietnam_Veterans_Memorial), [Washington Monument](https://en.wikipedia.org/wiki/Washington_Monument), [War World II Memorial](https://en.wikipedia.org/wiki/National_World_War_II_Memorial) [Answer] I really like the other answer for this question but I just wanted to add a little something to the discussion. The odds of a monument's survivability relies on the **massiveness** and the **maintenance requirements of the structure**. Materials also come into play as buildings made out of **ferro-concrete** are stronger but last less long compared to those that aren't thanks to rust if even a pocket of air exists in its structure (according to this [link](https://en.wikipedia.org/wiki/Ferrocement#Disadvantages)). I know you're focusing on the US, but consider the rest of the world as well - the **Pyramids of Giza** would definitely still be standing (unless our largest bombs were targeting Cairo), despite being thousands of years old already. **Chichen Itza**, **Machu Picchu** would also still be standing, as would more massive temples and ruins that were not located in big cities. Now to more modern constructions: massive baseball fields would probably still be standing, as would important government buildings and others. I know you asked about monuments, but 'regular buildings' would also be around - not looking as nice but still standing. For example, the capitol building in the town of Pawnee, Indiana (from Parks and Rec) would still be standing as I'm assuming it didn't get hit by a nuke. Our recipe for concrete isn't as good as the Roman recipe, but it's not terrible, so let's give ourselves a bit more credit :D Just wanted to add to the conversation as it seemed pretty 'dam'-heavy in the previous response. [Answer] (From the way your question is phrased, I'm assuming you mean "Leave remains that are recognizable as a man-made structure or monument" and not "Remain in working order." If you mean the latter, you way want to re-word your question.) The answer is that a great many things would survive. Five hundred years is not a long time, really -- just think how much has survived 500 years, after all nearly every medieval structure is at least 500 years old, and many of them have not been maintained: Castles, Roman roads, forts, tunnels, pueblos, quarries, bridges, aqueducts, walls, statues, churches -- there are vast numbers of things that survive. The two great enemies of human structures are glaciation (and 500 years is probably too short a time for the Earth to tip into the next ice age) and people. *People* can quickly destroy things by rebuilding right in the same spot and using the old structure's materials. ]
[Question] [ So I have a species of creatures who want to design a cannon using biological processes. Here are some things the cannon needs to do: 1. Launch a 4 pound (~1.8 kg) cannonball at around 1430 ft (~435 meters) to 1700 ft (~520 meters) per second. 2. Needs to take less than 5-10 seconds to load, the less time the better. One should be able to load and fire the cannon by himself. 3. The cannon needs to weigh less than one short ton and be carried and handled by the creature, much like a musket. The creatures can carry that much. 4. The cannonball needs to be fired only using biological processes which the cannon provides (i.e. the shooter only provides the cannonball for firing). 5. The means of propelling the cannonball must be produced by the cannon itself, which would most likely be a living creature. Source for muzzle velocity and cannonball weights [here](https://www.arc.id.au/Cannonballs.html). [Answer] Well, we know killer whales can definitely toss heavy seals a long ways (<https://www.youtube.com/watch?v=G7WGIH35JBE>), but that's a bit out of the scope of the question. The creatures are on land, and if they can carry 1000 kg, they are big. Could a natural gunpowder or equivalent be made? The bombardier beetle is one example of something that can generate two chemicals, and mix them on demand. From Wikipedia, "The spray is produced from a reaction between two chemical compounds, hydroquinone and hydrogen peroxide, which are stored in two reservoirs in the beetle's abdomen." Our comrades over at Biology tell us the maximum pressure inside BTW: <https://biology.stackexchange.com/questions/30143/whats-the-maximum-pressure-inside-a-bombardier-beetle> It's kind of low, so you'd get those elements separately (or from two different creatures, which is safer and easier). If you could find other creatures that had this capability, you could milk them in some fashion, so that brings the biological bit forward. For the cannon, you need to have something that can handle the stress of combustion or whatever pressure is driving this. In theory, if you had a cored out tree trunk that was massive, you might be able to handle that sort of pressure. What is the pressure? Firearms folks know a bit: <http://closefocusresearch.com/calculating-barrel-pressure-and-projectile-velocity-gun-systems> They assume average pressure is about 1/4 of the peak pressure. For an iron projectile (assuming a sphere), 7.8x that of water, that's about a 3" diameter shot. From the equation that the gun folks use, peak pressure of 3000 psi, with a 24" barrel gets you into the 500 m/s range. Bamboo might be used (ala Captain Kirk in episode with the Gorn), but Mythbusters has already busted that idea, but that's for a single bit of bamboo. Looking at mechanical properties of bamboo, tensile strength is 2000 kN/cm^2, vs 35000 kN/cm^2 for steel, about 1/15th. <http://bambus.rwth-aachen.de/eng/reports/mechanical_properties/referat2.html> If you make a piece of wood thick enough, you might be able to handle the stresses of whatever your propellant is. <https://en.wikipedia.org/wiki/Pressure_vessel> For large enough thicknesses of wood, you might be able to pull this off. Got to do some additional math to check this out. If the cannon is to be fed food, and produce the required reaction, then some sort of dual creature setup might work. One creature (or creatures) on one side of the cannon excretes compound A; another secretes compound B. When mixed, they ignite, or they become far more volatile. The problem with this is that biologically, you would be asking a creature to excrete something with high caloric/energy value, unless this can be justified for another evolutionary reason. As far as ignition goes, this discussion talks about some possibilities: [Can hydrochloric acid and digestive enzymes cause a fire?](https://worldbuilding.stackexchange.com/questions/17837/can-hydrochloric-acid-and-digestive-enzymes-cause-a-fire/17886#17886) For full completeness, Larry Niven's stage trees should be mentioned, and various similar systems: [Could plants spread their seed to other planets?](https://worldbuilding.stackexchange.com/questions/10914/could-plants-spread-their-seed-to-other-planets/10996#10996) [Answer] They can go along the path of [Ecballium](https://en.wikipedia.org/wiki/Ecballium), and genetically engineer it. [![enter image description here](https://i.stack.imgur.com/V2JBp.jpg)](https://i.stack.imgur.com/V2JBp.jpg) > > It gets its unusual name from the fact that, when ripe, it squirts a stream of mucilaginous liquid containing its seeds, which can be seen with the naked eye. It is thus considered to have rapid plant movement. > > > [![enter image description here](https://i.stack.imgur.com/Oo0rU.jpg)](https://i.stack.imgur.com/Oo0rU.jpg) [Answer] ## Option 1 : Throwing The bite strength of a crocodile is about 18kN. Making some big assumptions that a biological cannon is engineered, and assuming engineering can beat nature by about 4:1, you could create 3 m (9 ft) barrel that pitches or spits the cannon ball at the desired velocity. The energy requirement is between 40 and 60 kcal per throw, which is not unreasonable (a can of soda contains about 200 kcal). You could make the barrel as compact as 2 m (6 ft) by choosing the slower velocity. The governing equation is : v = sqrt( 2 s a ) ## Option 2 : Chemical Propellant As mentioned in other posts, it is possible to imagine an engineered organism treating glycerin with nitric and sulfuric acid to produce a meta-stable TNT, or other explosive chemicals. The pressure that the combustion chamber has to endure depends, again, on the muzzle length and ranges from 12 MPa for a 3-meter barrel to 52MPa for a 1-meter barrel and the higher muzzle velocity. According to Wikipedia, pine at 40 MPa could handle the lower range. There is also the possibility, if engineered organisms are a possibility, of naturally produced nylon (which can stand much higher tension) keeping the chamber together. There would have to be some sort of biological slide action allowing the propellant into the chamber, then sliding closed to protect those components from the combustion. A "tired" organism might misfire fantastically. From your link, I found the cannon ball diameter of 3 inches. The equation involved is P = F / A ## Option 3 : Rail Gun Alternatively, the cannon ball might have a small plug of conductive metal on it that the engineered organism could vaporize with a high current and conduct out of the chamber. The barrel pressures involved would be unchanged. Voltage isn't a problem here - electric eels (860 V) generate much more voltage than a rail gun might require (20 V). Power (P = V I) is a concern, but you might be able to handwave it. Neurons (the source of the electrical power) take between 1/200ths of a second to a little under a second to recover between firings. ## A Note to Consider For high-energy impacts (like canon shots) the velocity is not the most significant term in the penetration equations. What is "high-energy" depends on the target material, but once you are in this region Newton's penetration equation applies - penetration = bulletLength x (density of bullet / density of target material) Because of this, you may prefer long, spin-stabilized cannon balls and long barrels. [Answer] Well, you can follow the idea from [Warhammer 40k Tyranids](http://warhammer40k.wikia.com/wiki/Tyranids): They are a countless swarm of creatures that devours everything remotely organic, leaving on their trail only barren planets. The hive mind that controls them adapts the weapons the Tyranids use to match the situation. [![Your typical, friendly Tyranid Warrior](https://i.stack.imgur.com/FMEYI.jpg)](https://i.stack.imgur.com/FMEYI.jpg) One of the most iconic weapon is the Fleshborer: > > The Fleshborer, designated by the binomial Pulpa terebro, contains a compact brood nest where Borer beetles lay their eggs, which hatch and mature, sustained by the weapon for future use as ammunition. These beetles are kept in their mature state in a hormone-induced dormancy until the weapon is ready to be fired. At this point, neural impulses from the wielder forces one of the insects into a firing sphincter. From here, the beetle can be fired at a target by a further impulse. > > > The beetles move very little until the weapon is triggered by a massive electro-chemical shock which drives the beetle into sudden frenzied action. Using their powerful flea-like legs they launch themselves out of the weapon at tremendous speed. > The beetle itself is blind, having been specifically bio-engineered this way to lessen any possible deviation its flight path. On striking they expend their life energy in a matter of seconds, boring frenziedly through the target's armour, flesh and bone. If however the beetle fails to find a target, or hits something that even in its frenzied state it cannot bore through, it quickly dies regardless. The beetles secrete a potent digestive enzyme upon impact with a target, aiding the penetration of armour and flesh. > <http://wh40k.lexicanum.com/wiki/Fleshborer> > > > Now you can create a similar mechanism by itself: an insect colony would create a gun-like cocoon with semi-mature but dormant insects. Now when your user shoots the gun, the insects kill the prey gorging themselves on food. Now, the smart user can leave enough of the carcass to be turned into new gun-colony. [Answer] Very simple, just have a giant Elder Dragon put a 2kg rock in his mouth and spit it out as fast as he can. As a bonus you'll get a fireball. ]
[Question] [ I'm considering creating a fictional military organization designed in a highly organized and militarized manner such as you might find with the Norse of the 9th century... if the Norse had developed space flight, tanks, and powered armor. Some quick research left me with the impression that the rank structure of the Norse was very simple: King, nobleman, freeman, and slave. Rather than have slaves, I'm going to use "thrall" as the rank for anyone who doesn't enter the military. I found 3 cultural ranks that could be used: Jarl, Heisir and Thegn; and I'm considering as an example having a Jarl command 3 "boats" of 30 soldiers each, each boat is commanded by a Heisir, and each group of 10 soldiers are commanded by a Thegn. My question is, are there other existing "ranks" or "honor names" (I'm looking for the words) that could be used as military rank in a similar way? Please remember, my basic groupings are king, noblemen, freemen, and thralls. [Answer] You've got the main ones I think but here's a list of some others (as well as some anglicised versions of ones you've already got which might be more familiar to people). **Jarl** - *Earl* - Generally a nobleman or person of high standing. **Heisir** - *[Hersir](https://en.wikipedia.org/wiki/Hersir)* - Lesser nobility and landowners. Probably somewhat equivalent to medieval knights in a feudal system. **Thegn** - *Thane* - Similar to Jarls, a type of nobleman, usually in service to the King. **King** - *Konungr* - The head of state, fairly self explanatory. **Karl** - Literally means man but could also mean something like servant. **Huskarl** - House man, a term often used for soldiers sworn to someone's service (like a nobleman's guard) **Dreng** - *[Drengr](https://en.wiktionary.org/wiki/drengr#Old_Norse)* - A soldier or warrior, usually someone who is courageous or daring. **[Hird](https://en.wikipedia.org/wiki/Hird)** - "an informal retinue of personal armed companions" but came to mean the king's guard or household. **Skald** - A poet or bard **Thrall** - Slave **Berserker** - Champion warriors who fight in a trance like state. **Úlfhéðnar** - *Ulfsark* - Berserkers who wore wolfskins instead of bearskins. **Einherjar** - The chosen of the gods, dead warriors taken to Valhalla to feast with Odin until Ragnarok. There's also a whole host of mythological terms and beings whose names you could use. I'll list those too if they are of interest. As for the rank structure, 3 (and its multiples) was a very special and symbolic number in Viking culture so that would certainly make sense. I would say the Heisir / Hersir would be equivalent to a captain and would command a ship. I would then place Jarls above them as you have, commanding either 3 or 9 ships but I would probably put the Thegns above them as they are usually referred to as more directly responsible to the King. [Answer] @adaliabooks The input of 3 and 9 was very important - I did not recognized the strong emphasis on those numbers. Although it should be obviously 3 norns, 9 worlds... * recruits, conscripts, convicts are considered as **Thralls** * Enlisted are **Karls** or **Huskarls** * Non-commisioned Officer is a **Hirdmen** * Company Officier is a **Hersir** * Field Officer is a **Jarl** * General Officier is a **Hertogi** or **Konungr** In structure: * 1 Brigade = Konungr * 3 Regiments = Hertogi * 3 Battalions = Jarl * 3 Companys = Hersir * 3 Platoons = Hird * 3 Squads = Drengr * 3 Points = Kertilsveinr Its possible that a battalion CO is a Jarl and the XO is a Jarl too but both men and of course the men in the battalion should know who is superior. When they meet with other troops the senior might carry a symbol like a cord or seax. Other terms like Einherjar or Berserker might be used for specialists or are honor titles like Thegn, Skald or Vaeringi. ]
[Question] [ I'm working out the back story of a flying castle run by a king who has a squadron of 200 air cavalry. All the knights ride hippogriffs: head and wings of large eagles, bodies of horses. Horses eat oats. Eagles eat meat. How do I calculate how large the grounds surrounding the flying castle need to be, to grow enough oats and to supply enough meat (lamb? pork? goat?) to keep the mounts fed? My intent for the flying castle is not that it is a battleship. My intent is that there is a hemisphere of land which flies, and the castle sits in the center. The land supports the castle inhabitants (a thousand people) with crops. So, oats could be grown on the flying piece of rock around the castle proper. Technology level and tone is Age of Enlightenment with some magic. So, roughly 1730 to 1750. Edit: I'm asking for help calculating the resources needed to feed the mounts. I have an idea of how much land surrounds the castle to feed the thousand inhabitants inside: a radius of two miles, mostly fields with some small forests and hills. The lands around the castle have enough resources (fields) to feed the inhabitants. The castle can send parties down to trade for resources and to forage. I'm trying to work out what can be provided locally and what will be a problem. The castle is not a military team; it's a small town with a normal population distribution of a thousand people. Second Edit: while the castle might be five hundred feet or less from the surface, and be able to forage on the planet in times of peace, I'm trying to put together a plan for feeding the hippogriffs in times of war, when forage is not possible and the castle is over the ocean or the frozen north. [Answer] ## Food Since your hippogriffs have head and wings of large eagles and bodies of horses, their digestive system is one of a horse. Thus before assessing how much land do you need to feed the cavalry, we need to address the problem of suitable food. **Avoid Meat** Horses are herbivores, their digestive system does not work with meat that well. They can consume it in small quantities, but a diet rich in meat would kill a horse. This is actually good news. It is easier to grow and store plant-based food. **Oats Are Only a Concentrate** Horses also do not do that well if their diet is based on grains. Oats are useful for giving a horse some energy or gaining a bit of weight. However, a grain-rich feed may cause colic, which is frequently lethal. Under normal conditions no more than 40% of fodder can be replaced with concentrates. Oats can be given as the main food before the battle or when the cavalry is on the march. The riders should monitor their hippogriffs carefully to avoid overeating and colic. **Grass and Hay — The Horse's Best Friends** Grass and hay are the staples of the horse's diet. Grazing is the best option for a horse. Hay is the second-best option. They help to keep a horse healthy since they are rich in fibre. **Salt and Minerals** A horse needs a small amount of salt and minerals. They can be mixed into feed. Another option is to have a block of salt that a horse can help itself to when needed. There is no need to worry about overeating salt. ## Anatomy I am going to discuss beaks only. Eagle beaks are great for tearing flesh, but they are terrible at grazing and chewing grass and hay. Since hippogriffs are chimaeras, they can have beaks with teeth. (Interestingly, birds have [genes responsible for teeth](http://www.audubon.org/news/how-birds-lost-their-teeth) but they are deactivated.) You will need to experiment with actual anatomical placement, but teeth are absolutely necessary to keep hippogriffs healthy and happy. ## How Much Food Does a Hippogriff Need? A healthy horse eats about 2-2.5% of its own weight daily. On average, birds eat need 25-50% of their body weight. Hippogriff will probably have lower body temperature and will be flying less than an average bird since it can use legs to walk and run. So, I would suggest taking 5% of body weight as the lower limit (when hippogriffs are in a 'stable' during peaceful times) and 15% as the upper limit ('action mode': a lot of flying, fighting, pregnancy, etc.). I will use heavy war horses as a reference point for hippogriffs since you want them to carry knights. Medieval war horses weighted from [1,500 to 2,000 pounds (680 to 910 kg)](https://www.wikiwand.com/en/Horses_in_warfare#/Heavy-weight). Let's assume that an average hippogriff is about 1750 pounds (about 790 kg). Therefore, **it will need from 87.5 to 262.5 pounds (39.6 to 119 kg) of feed daily**. You can work out the yearly consumption depending on your political climate. ## Food Production You should use [crop rotation system](https://www.wikiwand.com/en/Crop_rotation) in combination with the hippogriff husbandry. Grow grass for hay and grazing and use manure to fertilise the land. It would be ideal to also have dedicated pastures where hippogriffs can graze freely. The pastures do not have to be on the same rock as the castle. However, in this case, enough feed should be stored in event of war. **Crop Yields** (see [this paper](http://www.basvanleeuwen.net/bestanden/agriclongrun1250to1850.pdf) for detailed information) *NB*: these are back-of-the-envelope calculations based on data for the Great Britain. Your climate and soil might produce different results. * *Oats*: approximately 12.3 bushels per acre (net yield; about 775 kg per hectare) * *Hay*: approximately 540 pounds per acre (600 kg per hectare; based on Medieval Inner Asia yields) The average storage losses due to spoilage were about 10%. The final calculations will depend on your decisions regarding the size of hippogriffs, their appetites, and lifestyles. [Answer] A horse eats 1/2 a pound of grain per 100 pounds of animal per day. For the ease of calculations, let's say your hippogriff weighs 2,000 pounds (a large horse's size). That's 20 pounds of grain per day. An acre of land typically yields about 33 bushels of grain per year. Each bushel is about 60 pounds. So you can feed three hippogriffs on one acre of land per day. To feed 200, you need 4,000 pounds of grain per day. That would be about 24,000 acres (or 37.5 square miles). Now, let's assume each hippogriff will eat a 50/50 split of grain and meat so cut those numbers in half (so 12,000 acres or about 19 square miles). Most big predators eat 4 to 7% of their body weight per day in meat. For ease, let's say 5%. 5% of 2,000 pounds is 100 pounds a day. Since we are assuming a 50/50 split works, that's 50 pounds of meat per day per animal so 10,000 pounds of meat per day. Cows could be convenient meat, but then you have to have more land to grow the grain to feed the cows. Some sort of roaming herds of large animals like elk that the hippogriffs could hunt would probably be easiest (I assume they'd have to live on the ground below the flying castle). **Per Day** 10,000 pounds of meat and 4,000 pounds of grain for your entire hippogriff population (Eating all grain or all meat would make this scenario a lot easier.) [Answer] **Type of food** Based on my image of a hippogriff, I would rather go towards them eating meat only. If you plan to have a vicious, bloodthirsty king, he could feed his beloved animals with human meat, mainly of the killed enemies and peasants who refuse to pay taxes. If, what I guess is more probable given the fact your castle is surrounded with fields and peaceful farmers, you plan to have calm and kind king, who uses his army only to defend his valuable castle, animal meat would be sufficient. I would guess rodents and small animals in natural habitat. However, if you need to feed an army, you would have to have a big farm for meat animals so something like chickens or rabbits is most probable. However, supplementing the diet with some kind of crop might be needed for economical purposes. **Calorie needs** Single, average working horse needs about *25 000 kcal* a day. If we imagine a horse with wings, which is used to fly around the castle by men in armor, I think we can call it "average work". However, maintenance of a single horse requires only *15 000 kcal*. So if all 200 hippogriffs don't fly around on daily basis, I guess we can set average need at about *20 000 kcal*. **Energy in food** Finding info about calories in animal meat wasn't easy as I assumed that hippogriffs can eats whole chicken/rabbit. Some forums claimed that a whole chicken (with skin) is about *1300* kcal. I am not sure if the number is including bones and other stuff humans don't usually eat - the answer may need some improvement. As the rabbits are generally less fat than chickens (about 220 kcal to 300 kcal) we can assume you would need 3 rabbits for every 2 chickens we need. If we would like to add some crops into the diet, corns seems like the best option with *1500* kcal per pound. **The math** Assuming average calorie need of 20k kcal per hippogriff, we need around 4 million kcal a day to feed whole army. That would translate to about 300 000 chickens. The number seems enormous, so that needs verification. The crops might be better documented (link below) so the math should be OK. An acre of corn provides 15 million of calories per acre per year. That means that corn that could feed your army for a year - 1,25 billion kcal - would take about 85 000 acres. **Summary** Letting your mounts feed in the wild may be a smart idea as feeding 200 horses is a costly task. Hippogriffs may easily hunt for the birds,rodents and even deer or eat grass in the meadows beneath the flying castle. It will make your life much, much easier. Links: <http://www.dayvillesupply.com/hay-and-horse-feed/calorie-needs.html> <https://www.washingtonpost.com/lifestyle/food/in-defense-of-corn-the-worlds-most-important-food-crop/2015/07/12/78d86530-25a8-11e5-b77f-eb13a215f593_story.html?utm_term=.dd22a1f16b76> [Answer] **What is a Hippogriff?** You appear to be taking the half-eagle/half-horse description literally. In this case, it's an omnivore where the front half and back half have different digestive needs. However, that's really unlikely to be the case. My answer will be from the point of view of horses because once the math's established you can apply it to any dietary requirements you wish. I bring this up because many a good story has fallen upon deaf ears for the lack of originality. Therefore, what, really, is a Hippogriff in your world? **The Dietary Requirements of ~~Horses~~ Hippogriffs** There is an issue, but I'll deal with that a bit later. And before we begin: remember that I'm ***oversimplifying a remarkably complex process.*** Merck has an excellent paper on the subject of [horse nutrition](http://www.merckvetmanual.com/management-and-nutrition/nutrition-horses/nutritional-requirements-of-horses) that covers everything from water to lactation. There's more to keeping a large animal alive than just the proverbial bread and water. Dietary requirements change for the different phases of the animal's life and (in your case) the different kinds of combat the animals may experience. *Water* A sedentary animal needs 5L/100Kg/day of water. Everything will increase this amount. Merck recommends unlimited access to clean water. That's a bigger issue for your flying island than food because water will be needed for everything: humans, animals, agriculture, driving the engines of manufacturing, sewer/cleaning... just to name a few. > > Most of the believability of your story will not revolve around the science of keeping Hippogriffs alive. It will revolve around the believability of your water sources. > > > According to the [USGS](https://water.usgs.gov/edu/earthrain.html) an inch of rainfall on one square mile results in 65.78 million litres of water. This sounds like an enormous amount until you realize how much water is needed for farming. [An answer to this question](https://www.quora.com/How-much-water-does-it-take-to-farm-one-acre-of-land-annually) suggests 3.5 acre-feet/acre of water per year. 640 acres/square mile: that's 2.76 billion litres annually or 42 inches of rain. (Remember that rainfall requirements depending on soil and crops will **vary wildly** from this figure.) This, of course, depends on your soil foundation, top soil quality, what food you're actually growing, where your island is (hot? cold? desert? jungle?), and your altitude (closer to the sun, [faster evaporation](http://www.wildbackpacker.com/backpacking-food/articles/high-altitude-cooking/), though it has little to do with the sun and a lot to do with air pressure). If you need to store the water, you need 2.76 million cubic meters of space. Granted, that sounds bigger than it really is. It's a fraction of the size of a city resevoir (on the order of 1/30th - 1/100th). But, you stil need to make the space, and I don't know how thick your island is. Lakes and ponds might have to be bigger than usual because you don't have the depth to work with. *Food* Merck has tables that indicate your average weight animal needs 16.7 million calories a day if idle and twice that for heavy labor (like combat). That sounds like a lot, but as it turns out, there's a difference between [calories, Calories, and megacalories](http://www.thewayofhorses.com/calories_0406.html). From the previous link we find: > > Once the hay test is completed, the results will show the digestible energy in the hay. It will appear on the test as "DE, equine Mcal/lb." For example, if the test reports a reading of 0.78 DE, equine Mcal/lb it means each pound of hay will offer 0.78 megacalories. > > > Using the adult 1,100 pound horse that is doing moderate work how much of this hay would need to be consumed? He needs 24.6 Mcals per day. Divide 24.6 by 0.78 which equals 31.5 pounds of hay. This horse is going to be in bad shape - there is no way he can eat that much. Better hay needs to be found (the best thing to do) or a concentrate needs to be fed. > > > And from [this site](http://thenaturallyhealthyhorse.com/horse-hay-statistics/) we discover how much hay/alfalfa/etc we need. For that 1,100 pound horse and assuming we get but one crop per year (REALLY IMPORTANT ISSUE) we get 0.03\*1100\*365/2000 = 6 tons of feed per animal or 1,200 tons for your cavalry. Reducing [this paper from Purdue University](https://www.agry.purdue.edu/ext/forages/rotational/articles/PDFs-articles/calculating-hay-yields.pdf) to the basic facts (and ignoring the complexities of soil quality, rain, sunlight, etc.) you get 3.4 tons of feed per acre per harvest. *Putting It Together* Assuming one harvest per year, you need 353 acres or 0.55 square miles just for animal feed and the ability to aquire or store 1.52 million cubic meters of water. (It's the same amount of rainfall, though, because of the change in acreage: You're still looking at 42 inches of rain, unless you allow space to lie fallow as a rain shed, which is a good idea. Farm an acre, use 3 for rain shed, now you need only 10-12 inches per year.). *One More Thing* But, there's that issue I mentioned. Hippogriffs *fly.* That means the high-energy requirements of birds. This is a pull-it-out-of-thin-air guess, but you'll likely need to double the food intake to sustain regular flight. That doubles the requirements of the previous paragraph. **But It's More Than Just Land — it's transport** The second biggest problem you face (next to water) is transport. What happens in a drought, or if some disease hits your crops, or you choose to reduce your landmass so that you're only self-sustaining for short periods of time during war? You need to move mass (water and food) from the surface to your island. Ugh. Some [gut reactions](http://www.horseforum.com/driving/how-much-weight-can-horse-pull-580850/) suggest a horse can pull up to 2X its weight, but really shouldn't carry more than about 15% of its weight (150# for a 1,000# horse) and generally can pull about 1.5X its weight. The problem is that you need to fly everything to that island. That means we're dealing with "carry" figures, not "pull" figures. Unlike a cart, which distributes the weight on the wheels thereby reducing the actual force load on the horse. Your Hippogriffs must carry the load as if it were on their back. If we assume you only use your Hippogriffs for transport, and that one rider can wrangle four cargo carriers, then you can move (on average) 120# per Hippogriff or 9.6 tons if the whole fleet is used. You need 125 trips (of the entire fleet) if you need to fully stock for a year. Take you, what, at lest a month... maybe two? > > Another chunk of believability in your story will be emergency preparedness, which boils down to transportation. How do you haul cargo to your island? You will need resources for animal maintenance, building maintenance, human maintenance, news & intelligence, and a host of other things. Yes, you can make most of it yourself (assuming nothing goes wrong), but you're just one natural disaster away from everybody dying if you only have 200 fighting birds. You'll need a reasonably comprehensive transport system. If you're only using hippogriffs, you'll need another 100 for regular transport and probably another 100 to swap out animals who are sick, injured, pregnant, tired, etc. > > > Note that I just doubled your landmass. > > > **Your Last Problems: Metal, Wood, and Coal** Finally, a floating island will have little in the way of mining or logging. You'd need a floating state to have enough forest to be self-sustaining with wood, and even if you created a big enough floating island to have mining, it's a finite resource. You need to move metal and wood to your island, exacerbating the transport problem because they're both heavy. On top of that is the need for heat for everything from comfort to cooking to metalworking. I'm assuming coal for convenience. And that's assuming you're not building your fortress/castle out of stone. Granted, after it's built all you need is maintenance... but rocks are heavy. > > Water and transport... they're the real problems. > > > **TL;DR** That was a book. If you read it and all the supporting links, you're well educated! If not, here's the short and skinny: * You need about 4 square miles dedicated to food for your Hippogriffs. One for actual production, three for rain shed and rotation. * You need about 0.33 square miles dedicated to water storage... assuming your island is funnel-shaped and every drop of rain water is channeled to the lake. If not, it'll need to be bigger. **And while I'm thinking about it, attacking your island from underneath to punch a hole in the lake would be a great tactic for your enemies....** * You need 100–200 Hippogriffs in addition to your cavalry for supporting functions including transportation and down-time replacements. * You need regular transport (as in nearly daily transport) to keep non-renewables in stock including metal, wood, stone, and burnables like coal. ]
[Question] [ **The Scenario:** My late Victorian Era mad scientist wants to domesticate the dinosaurs and mammalian megafauna of his "Lost World" island getaway, for use as companions, guardians, draft animals, and even mounts for his many henchmen. The problem is that he doesn't have thousands of years to do it. In fact, for the timeline of the story to work, he needs to succeed in under a decade. That makes true domestication, via selective breeding, impossible. The solution will probably have to be a bit slapdash. The best I can think of is psychosurgery, primitive deep brain stimulation, or some kind of behavioral training; but I'm open to all ideas. Being a mad visionary genius, I don't mind if he jumps a bit ahead of the real world technological timeline, or stumbles onto something not yet supported by scientific theory. That said, I don't want whatever method he settles upon to be easily reverse engineered into a wider variety of setting-breaking technologies. Internal consistency is important to me. Finally, while I'm fine pushing the limits of the possible, and exploiting the unknowns of brain anatomy and behavior, I'd like to keep things as close to real world science as I reasonably can while still getting the effect. That way I'll have a much clearer idea of what my characters can and can't do, and hopefully be able to add texture to the world by referencing actual scientific developments. **The Question:** Given the above, what is the all around most effective way for my mad scientist to go about domesticating his new menagerie? [Answer] # Selective Breeding Don't rule out selective breeding too quickly. If any of the megafauna reach sexual maturity within one or two years, a decade is plenty of time for a selective breeding program. Beginning in 1959, the Soviet scientist [Dmitry Belyayev](https://en.wikipedia.org/wiki/Dmitry_Belyayev_(zoologist)#Belyayev.27s_fox_experiment) bred successive generations of wild silver foxes to produce tame ones. He produced human-friendly foxes by the **fourth** generation; his foxes were very friendly (eager for human contact) after only **six** generations. As explained in [Scientific American](https://blogs.scientificamerican.com/guest-blog/mans-new-best-friend-a-forgotten-russian-experiment-in-fox-domestication/): > > Starting at one month of age, and continuing every month throughout infancy, the foxes were tested for their reactions to an experimenter. The experimenter would attempt to pet and handle the fox while offering it food. In addition, the experimenters noted whether the foxes preferred to hang out with other foxes, or with humans. > > > Then, upon reaching sexual maturity (seven to eight months), they had their final test and assigned an overall tameness score. They rated each fox's tendency to approach an experimenter standing at the front of its home pen, as well as each fox's tendency to bite the experimenters when they tried to touch it. Only those foxes that were least fearful and least aggressive were chosen for breeding. In each successive generation, less than 20 percent of individuals were allowed to breed. > > > A notable downside is that such a targeted breeding program (seeking only to make the animals tame) might negatively impact their suitability for other tasks. For example, if their fear response to new people and situations is reduced, their utility as guard animals similarly decreases. Of course, generally the bigger the animal, the longer it will take to reach sexual maturity. A fox may reach sexual maturity in seven months, but a bear could take three years, and an elephant takes at least 15. But if you decide your dinos are more like birds, ostriches can sexually mature between 2 and 4. # Training Of course, animals don't necessarily need to be domesticated to be trained. Wild-caught raptors were historically used in [falconry](https://en.wikipedia.org/wiki/Falconry_training_and_technique), although in most modern countries this is now illegal, so only captive-bred birds or birds taken from wild nests as eggs or nestlings are used in modern falconry. If your scientist can somehow acquire a juvenile and imprint on it, that could facilitate training. Human history is replete with examples of dancing bears and circuses that feature tamed lions and tigers; [Isaac A. Van Amburgh](https://en.wikipedia.org/wiki/Isaac_A._Van_Amburgh) trained large wild cats for public exposition in the 1830s. His methods were reportedly quite brutal, involving both starvation and beating the animals with a crowbar. Carnivores may be easier to train than prey animals as they would arguably be less afraid of new experiences (hence the early domestication of dogs in human history). In addition, their natural hunting instincts can be integrated into the training process, as with falconry. A well-read Victorian-era scientist could conceivably be familiar with the basics of falconry; the Old Hawking Club was founded in Great Britain in 1864. [Answer] **It all depends on the dino** Selective breeding only takes a few generations, animals can be domesticated after a single generation under the right conditions, but if you want untrained people handling them more is better. The big wrench in the works is whether the animal is suitable for domestication, if it's not, it will never be domesticated without genetic engineering no matter how much you want it. There is a reason we domesticated horses but never zebra, zebra are just to aggressive. Generally animals that are solitary, strongly aggressive, require unusual breeding conditions (like Leks), or require specialized diets are unsuitable for domestication. So for dinosaurs the only two you can determine with any reliability is the first and last. So you want pack or herd living dino that does not have a highly specialized diet. Diet just rules out things like therizinosaurus and Spinosaurus. We can guess a bit about aggression by defenses, Stegosaurus has a very active defense meaning it will probably be very aggressive. But for most dinosaurs we don't know so you only have about aggression. So mostly you only have to worry about how social the dino is. We know of social behavior in **Hadrosaurids, Ceratopsians, Sauropods, Tyrannosaurids, Dromaeosaurs and Allosauridae**. so you are fine with any of them. But you can always "find" a few social species in the other groups. If you want it to feel realistic there should be a lot of trial and error in finding suitable species. Taming animals is easier but you need new wild ones to get more, and it is time consuming and very costly yo break and train them. And it is important to remember a tamed animal is always dangerous, there is always a risk its anger at the monkey poking it will outweigh its fear and it will kill someone. For non-dinosaurs you need to be a bit more specific, keep in mind if you go back past the triassic the oxygen problem starts popping up. Just FYI Keep in mind triassic and jurassic grazing dinosaurs would not be able to eat grass, it had not evolved yet and has some unique defenses. [Answer] Your animal trainer can probably harness them. Of course, you failed to specify which megafauna your island had. I think it would even be possible to pacify them, at least to some extent. By "pacify" I mean something like a frontal lobotomy, so that much of their aggressive normal behavior was removed. The problem with this is that then they'll be wimps. The real question is: why on Earth do you think this would be an efficient use of food? People don't use goats (not counting Thor) to pull wagons. Why? Because oxen and horses, mules, etc. are *better* at it. What are elephants used for? Plowing fields? Not so much. Lifting heavy loads? Somewhat. War? Yup. So, what use would a dinosaur actually be compared to the most effective animal used today? I doubt they'd be able to compete, but that's just speculation. We don't know anywhere near enough about their behavior and metabolism to justify a firm opinion. Maybe working in swamps? I really don't think they'd be very useful. Sure, one could lift loads you'd need a team of horses (oxen are generally more favored), but who is going to ride a dino to the saloon for the nightly hee-haw? (Incidentally, I think they'd be pretty much like elephants, mostly a status symbol.) [Answer] I'd go with mad-scientist *chemistry*, better living through better drugs. You train them the same way we train other animals; with sticks and carrots. But instead of getting physical (electric shocks or mere food), let's use some awesome drugs. First, a knockout dart: He can fire it into a Brontosaur and within an hour or so, it gets sleepy, lays down and falls asleep for a few hours. Doctor Crazy then attaches a collar to the dinosaur with surgical ports, the collar contains a fair amount of drugs to cause three things: Pain, Intense pleasure, or another Knockout (so he can refill when needed). These are triggered "remotely" by whistles (the mechanical kind) of one particular resonant frequency (different for each drug) that makes the membrane holding the drug in its vial permeable, so a dose leaks into the bloodstream of the animal (that's we we needed those surgical ports). Make sure Doctor Crazy invents chemicals that work in tiny doses. Then let the Pavlovian training begin! [It works on animals as dumb as flies;](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2814444/) it can work on dinosaurs. [Answer] With that short a time frame you are looking into the dark side of domestication. Electric pokers, drugs, lobotomies. Basically anything PETA would have nightmares over and that will work on a short term but probably shorten the lifespan of the creature. On the other hand victorians where master breeders (phrasing!), and maybe they could work out something like crossing one big strong dinosaur with a smaller tamer one in order to produce a mule like dino. It would depend on the scientist to have a way to discern what dinos can be compatible in that way. ]
[Question] [ My Mary Sue Marty Stu has a divine blessing which increases his muscle strength threefold. This has relatively precise meaning: if before blessing he could push horizontally some weight with the force of, say, 500N, after the blessing he pushes with the force of 1500N. Muscles at the moment of pushing started contracting and the resulting motion of limbs should have been exerting 500N of force but the blessing added 1000N more. To preserve 2nd law of thermodynamics the energy to increase the force comes, say, from some distant star. It's the deity we are talking about. Given such a blessing, how the routine activities change for my character? 1. Running (how the speed and the motions themselves change) 2. Jumping (how the height/length and the motion itself change) 3. Grappling, climbing 4. Punching, kicking things 5. Pulling, pushing things 6. ??? Are there any caveats I should be aware of? I came up with two caveats: 1. There are muscles inside the body, especially the heart. This is solved by blessing only external muscles, the ones directly below the skin which move our limbs and keep the spine and belly. 2. Neural system is not accustomed to increased effect of the motions. The accommodation process is the important part of the plot. Thank you. :) **EDIT 1** I must note that the basic idea behind the blessing is that the *strain on the muscles does not increase*. Energy expenditure of the body stays the same - only the resultant effect is tripled. If it's implausible I would love to read the deconstruction - it will help me modify the idea! **EDIT 2** I understand that to keep normal behaviour the character in question will need to accommodate to do the same motions with *less* force than he was accustomed to. My question is about the effects of tripling the strength. If there's backlash to it, so be it. :) [Answer] # Regarding bone and tendons First, let us assume that the physical parts of the body can handle the additional strength. A 175 lb trim person can bulk up to 250 lb and triple their strength in most weight-lifing measures; 50 lb + weight gains are par for the course for professional NBA or NFL players. This is accomplished while not breaking any bones or tearing any tendons (usually, though such injuries are relatively more common in pro athletes). However, this person's agility and movement is now limited by their new weight. The chief advantage of this magical strength blessing is the increase in power to weight ratio. If you could maintain your 175 lb mass but triple your strength, you would see significant benefits in speed and agility. Now to use a sports analogy, just because you are 175 lb but as strong as a 250 lb defensive end doesn't mean you can do what a defensive end does. Your mass is still low, and mass counts for a lot in certain kinds of combat (such as blocking NFL linemen, or tackling). However, if you are 175 lb and as strong as a 250 lb NBA power forward, or NFL running back, you will see the large returns on your agility. So regarding combat overall, it depends on what you are doing. Getting stronger won't help you as much in combat that depends on the push (locking shields Greek phalanx style, or charging an opponent with a couched lance) but will help you a lot when you can combine strength with agility (shooting a composite bow from horseback, throwing javelins, or dueling with swords) # Specific motions **Running** is limited by the force of gravity pulling you down. You take a stride and then you have to be pulled to the ground by gravity in order to make contact with your next stride. Increasing your stride rate is an option, but not as good of one: increased rate causes increased friction and will cause cooling problems. Someone with a magical strength blessing would be better off looking somewhat like the astronauts on the moon, hopping around with unbelievable stride lengths. However, this would take some time to get used to, and you might not really be able to utilize your full power. **Jumping** is much more straightforward. The work done by a jump is force times distance; if your legs are just as long and the force increases by a factor of 3, then the distance increases by a factor of three. The work done by the jump will all be converted to potential energy at the height of the jump. So $F\cdot d = m g h$. Since distance, mass, and gravity are all constant in this case, force is proportional to the height jumped. If you can jump with three times more force out of your muscles, you can jump three times higher. An impressive initial box jump of 1 m would turn into an unbelievable box jump of 3 m. Unfortunately, as @JasonK points out in the comments, landing from a 3m fall isn't exactly trivial. Humans just don't jump that high. You may have enhanced strength, but you don't have enhanced durability. Even if you have good technique, jumping this high frequently will get you a sprained ankle or stress fracture sooner or later. **Grappling** is something where you will be limited by mass. Instead of the ratio of your power to your weight, what matters is the ratio of your power to your opponents weight (and his power to your weight). For example, if the 175lb trim blessed warrior is 20% stronger than his 250 lb opponent, he is still at a disadvantage due to the mass disparity being more than 20%, assuming fighting skill is equal. This would be the classic MMA battle of striker vs. wrestler, where your blessed character would work hard to avoid the ground and pound. Climbing wou **Climbing, punching, kicking, pulling, and pushing** should all scale about linearly with increased strength, at least for reasonably small strength gains like a factor of 3. [Answer] You're only considering strength, but our superhero pals have other issues, most notably of an energetic and thermodynamic nature... * Base strength If the superhero is a wet noodly nerd, and we multiply his strength by 3, he probably won't get as strong as a normal bodybuilder... So he's still gonna need to go to the gym! However he'll get 3x more benefits than a normal guy. * Techniques A scrawny black belt has a good chance of wiping the floor with a meathead who doesn't know how to fight. So your guy will have to sign up on a dojo or something. * Self-preservation We have sensors in our tendons to make sure we don't rip them out. They provide feedback to the muscle. People who experience convulsions or uncontrolled muscle contractions can pop joints and snap ligaments... So gotta suppose his bones, tendons and joints have been upgraded too. He's also gonna need special shoes and gloves... 'cause you can destroy your knuckles when punching something with normal strength, so super-hero strength is even worse! After breaking his wrists a few times, I'd guess he's gonna opt for a sword or something. PS: head-butts wouldn't be a good idea. * Speed With 3x the strength he can swing a sword 3x as fast, or swing a heavier sword at normal speed and hit harder. There's a compromise here. Punching or running might be limited by other factors (ie how fast the muscles can contract) and of course if his brain/nerves runs at normal speed or not. Being startled and jumping up might result in head-butting the ceiling. * Energy Our muscles use energy storage molecules ([ATP](https://en.wikipedia.org/wiki/Adenosine_triphosphate) and [Phosphocreatine](https://en.wikipedia.org/wiki/Phosphocreatine)) which are immediately available but have very limited capacity (a few seconds of effort). These are replenished by mitochondria using respiration if there is enough oxygen present, or lactic fermentation if there is not. So, your superhero might have super-strength, but the same energy reserves as a normal human... in which case he'll punch super hard, but tire a lot quicker. You'll also need to boost his recharging rate by star magic influx... but there might be various inconveniences before he gets used to it. * Power and endurance If he climbs uphill 3x faster than a normal human, then he'll use 3x the power, which means he'll need 4 extra lungs and 2 extra hearts to process the extra oxygen to produce this energy. Okay, star magic. * Heat We're only 25% efficient, so when we expend 1 joule in muscle output, we heat up by 3 joules. If his power triples, his heat output will also rise... so he might cook himself to death. The fairy could give him a more efficient metabolism. [Answer] I am afraid that increasing muscle strenght by a factor 3 and leaving the bones and tendons the same will work like installing a 500 cc engine on the chassis of a 50 cc scooter: the chassis will soon get broken by forces exceeding its operating range. If you push 1500 N with your arm, your arm is also receiving a 1500 N push (good old Newton's law). If your bones and ligaments are not used to withstand that force, they can break, immediatly or over time. [Answer] I have bad news. The body adapts to whatever loads are placed on it. This is why astronauts suffer severe muscle atrophy in microgravity (from lack of use) and why body builders grow huge muscles (from repeatedly pushing the muscles to a large percentage of their limits\*). We don't perform normal everyday tasks at the limits of our strength. Mary Sue still needs to e.g. not crush an egg while carrying it, walk around without knocking things over, etc. and her muscles will react with atrophy since they are now being used much less. There are a few things where she will likely use high strength (opening a tight jar of pickles, running when late, moving furniture, slapping heretics, etc.) but most of these are not routine tasks and in exercise, **consistency trumps intensity**. The only way Mary Sue could maintain her full abnormal strength is with abnormal exercise. Even with an intensive training regimen, I expect she will suffer a bit of muscle atrophy and people may comment on how skinny she is (unless the balance is made up with fat). Without it, I expect her to be extremely skinny and not all that much stronger than normal folks. P.S. I just noticed you used "he" with Mary Sue. I'm too lazy to change all the gendered words. \*Yes, I know about roids. Contrary to popular belief these don't make you big by themselves. They speed up protein synthesis so that you can grow muscle faster *by exercising* and also reduce recovery time so that you can exercise more often. ]
[Question] [ One of the strangest and most effective weapons in the wonderful world of arthropods in the proboscis of the famed assassin bug, with even the head of the insect working as part of the weapon. [![enter image description here](https://i.stack.imgur.com/HtVO2.png)](https://i.stack.imgur.com/HtVO2.png) The "bite" of an assassin bug is a four step method. First, the bug impales the exoskeleton of its prey with its proboscis. They will then inject a venom that paralyzes the victim instantly before pumping it full of digestive fluids. Finally, the bug sucks up its meal. This is obviously terrifying, it's the equivalent of a war pick on the face of an insect. Rather, it would be terrifying if it were even a slight threat. The problem here is their size. If they were larger, they would be a major threat, but alas, the square root law destroys this dream. But, what if we just take the feature we want? Is it possible for a vertebrate to have a mouth in the style of the assassin bug? If so, how big can it become? If not, how close can we get? [Answer] **If a creature evolves an appendage, the advantage this appendage provides needs to be substantial enough to push the evolution of that appendage to completion**, eg. a tapir-type nose evolving to an elephant-style trunk as a very useful and multi-purpose breathing and manipulation digit. A larger body needs energy in larger quantities and roughly more evenly to sustain that size. A proboscis can only suck in liquid substances, necessitating that the creature either feeds exclusively on liquids (like butterflies but you'd, umm, really need humungous amounts of tree sap or nectar to sustain a large-sized body) or liquefies its food using some kind of venom/enzymes (again, needs to liquefy large amounts of food to sustain itself, though not as much as simple-sugar nectar). Any solid material getting jammed in the proboscis is going to be tricky to get out, so the proboscis itself will have to be narrow as a matter of self-protection, restricting the amount that can go in at a time and prolonging feeding time. If this proboscis is involved in injecting the liquefying venom, it will have to be narrow and sharp to be able to pierce through even soft skin like ours, mosquito-style. If there are insect-like chitin shells, tough hides and scales involved, this appendage will have to be pretty strong to avoid getting damaged. To get enough nourishment out of a 'kill', it will need to liquify a large amount of mass in a short time. If this means the venom is strong and can liquefy even large amounts of protoplasm fast, the problem of production and storage of this venom will mean proboscis-creature will need specialized organs to deal with large amounts of this highly corrosive substance. Else it means it will have to inject the prey multiple times all over to ensure it liquefies properly. Either way it will need to wait before the prey is sufficiently liquified to eat. This may be a longer wait than it can afford, especially if there are super-predators that prey on our proboscis creature. The closest to this ambush/trap/attack and liquefy strategy is spider-venom but even a spider eats semi-solid chunks along with partially liquefied matter. The ability to process solid/semi-solid diet via teeth/digestive enzymes enables the creature to ingest more matter, reduce wastage of good edible matter and hastens a creature's departure from the 'kill scene'. There's no reason why a creature should not evolve an injecting apparatus like hollow teeth or fangs but restricting it to feed via this apparatus would turn detrimental to its survival. So, no, I don't see this creature getting very big, a quarter plate-sized ambush specialist at the most perhaps but then it would have to compete with the comparatively more efficient spiders in that size bracket. [Answer] Depends if you want it inside or outside water. The [Pistol Shrimp](https://en.wikipedia.org/wiki/Alpheidae) has a similar weapon. It kind of cogs it piston then bursts it forward with enough force to break glass. However it's tiny, growing up to 5 cm/2 in. [![enter image description here](https://i.stack.imgur.com/T0HNx.jpg)](https://i.stack.imgur.com/T0HNx.jpg) A better candidate would be the [mantis shrimp](https://en.wikipedia.org/wiki/Mantis_shrimp). These guys come in two forms. One is more akin to a praying mantis. It has long spearlike claws. The other closer to our previous friend the pistol shrimp. The guy pictured above is one. See that sphere at the end of his limb? Like the pistol shrimp he can cog and launch it forward. However this guy doesn't just break glass. He is known to break finger bones. Or as Wikipedia puts so well: > > Both types strike by rapidly unfolding and swinging their raptorial > claws at the prey, and can inflict serious damage on victims > significantly greater in size than themselves. In smashers, these two > weapons are employed with blinding quickness, with an acceleration of > **10,400 g** (102,000 m/s2 or 335,000 ft/s2) and speeds of 23 m/s from a > standing start.[10] Because they strike so rapidly, they generate > vapor-filled bubbles in the water between the appendage and the > striking surface—known as cavitation bubbles.[10] The collapse of > these cavitation bubbles produces measurable forces on their prey in > addition to the **instantaneous forces of 1,500 newtons** that are caused > by the impact of the appendage against the striking surface, which > means that the prey is hit twice by a single strike; first by the claw > and then by the collapsing cavitation bubbles that immediately > follow.[11] Even if the initial strike misses the prey, the resulting > shock wave can be enough to stun or kill. > > > These guys are lethal. They're also much larger then the pistol shrimp. The largest ever caught being 46 cm/18 in. That's significantly larger than any bug. It shouldn't be too hard I imagine to scale it up slightly and then add the proboscis in the center. I'd say 50cm long is absolutely doable, larger probably as well but I'm not sure how well it would work on land. [![enter image description here](https://i.stack.imgur.com/fXfqp.jpg)](https://i.stack.imgur.com/fXfqp.jpg) [Answer] As explained by artemissunshine, it seems unlikely. Besides, liquefying your meal only works if it comes wrapped in a convenient carapace which can then be sucked empty. Enzymes that liquefy vertebrate meat would also dissolve the skin, and your tasty meatbag would end up a puddle on the ground... so it would have to be wrapped in something prior to digesting. I suggest quick-dry green slime. However, we can do more nasty stuff with a proboscis! <https://www.youtube.com/watch?v=6JKBQnNs_wk> Why not use it to shoot eggs or larva inside the victim instead? [Answer] Snakes inject their venom through hollow teeth, and the narwhal has a pretty large, weapon-like tooth. Since the probable prey of such a large creature would probably not have an insect-like anatomy, the injection of digestive fluids would seem unlikely. ]
[Question] [ My Kepler Bb humanoids develop cognitive, social, and motor skills faster than humans. Their growth rate though is slower than it is in humans. And they are physically gender neutral until 5 years old(the only way to tell gender before 5 years is via a genetic test). 1 very important motor skill that is absolutely essential for living underground is climbing. The baby room has rocks that go from the crib to the chamber right above it. This helps them climb. [![enter image description here](https://i.stack.imgur.com/7WKLI.jpg)](https://i.stack.imgur.com/7WKLI.jpg) It is kind of like a human child climbing a tree except that with shorter arms, many more rocks are needed. But yeah, these babies are able to climb at 2 months old(or so I thought). Just to put that in perspective, the year on Kepler Bb is 20 months long and a 2 month old human baby can't do much other than smiling and push ups. So that means that they would have to be able to get up by themselves practically from birth or at least a few weeks after birth. A newborn standing in just a few weeks is a bit too much in my opinion. So I have these major motor milestones so far: 2 months: Climbing 3 months: sitting without support 6 months: standing without support 9 months: walking 1 year: running and jumping What should I do about this climbing milestone? I still want it before 1 year old(so before 20 months) and I want it as early as it is plausible. But if climbing requires that the baby gets up, than that would require the baby to be able to stand up(and not just as a reflex). All these other early milestones look like they are at a reasonable point in time, it is just the climbing that looks like it is at an unreasonable point in time. **So how early is climbing plausible given that these babies can stand up on their own at 6 months?** [Answer] A good comparison for development milestones in climbing humanoids would be chimpanzees. Luckily, the Dallas zoo tracks the development milestones for their [young chimps.](http://zoohoo.dallaszoo.com/tag/kona/) For young chimps, climbing begins around 5 months, about a month after they start crawling around on their own. This is also the point in time when they take their first non-quadrupedal steps. Carrying this over to climbing humans, they'll probably start to climb around the same time as they start to walk. Based on your development chart, this will probably be around 9 months of age. One other important thing about baby chimps is that they aren't left on their own on the ground. Instead, they tend to cling to their mothers or other older relatives most of the time, which they're capable of doing from a much younger age than they can climb from. Climbing humanoids would probably do something similar, since my guess would be that this stage of development is important for developing grip strength, which is critical to climbing ability. [Answer] To be able to climb, you also need to be able to control your back muscles. this is also needed to walk or crawl. Else you would just rely on your arms and legs to move your body around with a loose abdomen. In your development line, this appears to be between 3 and 6 months. [Answer] What is their native environment like? Why the need to climb? You mention that the nursuries have rocks which lead up from their cribs. Consider kangaroos: when born, the fetuses must climb up from their mother's uterine portal to the pouch on her belly. There, they attach themselves to a nipple from a mammary gland and continue to grow. They won't be developed enough to stand, much less hop, for several months. Are these humanoids of yours placental, marsupial, or some combination? Well, that doesn't really matter all that much; marsupials can have a smaller birth weight but they require earlier development. You didn't mention the developmental milestones for a few other things, like rolling over or crawling — it looks like we could place those at 6 weeks and at 5 months, respectively. However, that doesn't necessarily matter: If the environment in which these infants are required to climb does not require them to use the postures and movements necessary to crawl or turn or sit upright, then there's no reason why they couldn't be able to do so much earlier than those other things. The environment being conducive is quite necessary, though, unless your humanoids go through different development compared to us: e.g. lower birth weight, earlier development of torso compared to hips and legs. ]
[Question] [ How could you create a forest in a space city, like the Citadel of the *Mass Effect* game? Would this forest provide renewal of oxygen for the population? Is it "simple" to create an atmosphere and airflow to ventilate the entire city? What are the requirements for growing the forest and ventilating the entire city? The city has about 1 million people. Does it take much technological advancement from the present for this? [Answer] # Lonely Forest The hardest part of the construction is the biosphere creation, hardest in terms of answering the question - how far are we from being capable of building such city. It is not hard in terms of actual doing, it is hard in terms of the knowledge we need to do so. A forest can't grow alone, just as a plain set of trees. To allow access of humans to those trees it needs to create some kind of microbiological system which is robust to possible microbiological outsiders. Some small creatures which form robust system to protect the system from possible small creatures outsiders and who manage microbiological compnents of the system(like worm do, and not only they). Might be even birds and animals to control parts of the system - insects, worms, etc. There have to be a stable system of [Primary producers](https://en.wikipedia.org/wiki/Primary_producers) and [Consumer's](https://en.wikipedia.org/wiki/Consumer_(food_chain)) If it will be too big(quantity of components), it will be hard to model the behavior, to monitor the changes, to notice new components (invasion, mutations), to control the system in a meaningful way(modify it). Too few components and the system will be not robust (high fluctuation of producents and consumers (back and forth in quantities for both of them) as an example of such situation are rabbits, rats in Australia. [Rabbits in Australia](https://en.wikipedia.org/wiki/Rabbits_in_Australia)). Such problems can be incorporated into the design of the system and result might be hard to compensate. If do not care about the problem then strict Australian rules about biological control will be easy cheesy compared to the rules which the city might need to protect its forest ecosystem. Also, interesting story to read is [Biosphere 2](https://en.wikipedia.org/wiki/Biosphere_2) experiment and the types of problems they had (They got the negative results.) It has to be remembered that a human has symbiotic relations with over then 3000 species of microbiological life(I mean guts microflora mostly, but there is more than only guts microflora). And the funniest part about microbiological life is it very very much like to mutate. And mutations are the process which made a human from a single cell organism. And it will not take a lot of time to mutate from [E. coli](https://en.wikipedia.org/wiki/Escherichia_coli) into something which considers the forest as the food substrate - in the ideal case of course when there is a sterile forest waiting for adventures of E. coli. Eliminating the human access to the forest almost eliminates the need to have it. So the problem of creating the ecosystem is a real key problem for the city. There is a lot to say, very exciting set of problems - how to exchange flora and fauna with other cities, how to control everything, how to ensure all humans have similar immunity, fighting diseases, biological control on all levels, all those procedures sweet sweet Grail of biological questions which are so interesting to solve and which will never end. # The rest Compared to creating the biological system which is suitable for the city everything else is fairly simple. At the moment we probably have all necessary technologies to do such a city, and the main thing which stops us from being capable of doing so is the absence of easy access to space and absence of manufacturing capabilities in space. As for the construction interesting work to read [O'Neill, G. K: The Colonization of Space, Physics Today, vol. 27, no. 9, Sept. 1974, pp. 32-40.](http://www.nss.org/settlement/physicstoday.htm) it does not look that complex after all. Also interesting material here at nasa site about possible settlements and their requirements and different considerations <https://settlement.arc.nasa.gov/75SummerStudy/Table_of_Contents1.html> # more about your questions particularly Yes, a forest can produce enough oxygen, same way as any plant. How much is it needed per human - the need is about the same amount of square meters as for other plants, 100-200 m2 should be close enough to be sufficient(more if there more consuments, not only humans) - in average 1000m2 should be more than enough in most possible cases. Yes, it is simply to create the atmospheres (whatever it means) and ventilate the city. The city is artificial construction, it contains nothing which was formed by nature and entirely is a product of human activity. Ventilation systems are part of the construction, by design, but as construction, they are a subset of much bigger construction. In the O'Neil project, natural convection created by warm-cold air will work. There can be different solutions and they might depend on the implementation of the city, but in general it is not that of a big deal. But with big open spaces heating the surface and might be cooling some high spots will be enough to create sufficient air flow and possible even winds. Basically creating a draft, not need in moving parts or big fans, just heating and cooling, the same way as chimney stuff works. Key problems so far are biology and access to space. Acces to space the problem will be probably solved by SpaceX, biology is what is left. [Answer] > > Does it take much technological advancement from the current for this? > > > Yes. A lot. But not due to forest thing. We simply need to get to the "space cities" state of technological advancement, and we are not even close. # Why to make a forest? Certainly **not** to scrub CO2. You would need to somehow remove created biomass from the forest to keep the balance. It is much easier done with hydroponic crops, where you can get CO2 removed, O2 released, and plant matter can be used as food. Forest's meaning would be negligible compared to hydroponics. So why? There are many valid reasons: 1. **Psychological effect.** Possibility to sit in nature-like environment, where you do not see artificial walls because trees obscure them, and don't see ceiling because in woods you rarely see sky anyway, can be a great relief on long missions. 2. **Habitat for endangered species.** Especially for small birds and animals. This is really good for PR, and good PR helps with getting money to build your station, and keep it running. 3. **Space tourism.** First forest outside Mother Earth! See trees that grew with artificial gravity, what fantastic shapes they made! Again, funding. 4. **Biological experiments** - Who knows how lack of gravity, or your kind of artificial gravity, would affect trees? For sure I don't. # How to make it happen? You need to read about the roots of trees you want to have in your forest. I think [this page](http://www.hellistreeconsultants.co.uk/kbi1000014_tree_root_systems.html) is one of decent starting points. [![Root system](https://i.stack.imgur.com/4KllB.jpg)](https://i.stack.imgur.com/4KllB.jpg) You need to make sure you have enough of soil for roots, and walls / floors strong enough for roots not to penetrate them. This is a lot of mass, and mass is expense when we talk about space exploration. For now, it's expensive. Can't find reliable sources, but it's above $10,000 per kg, as far as I remember. You also need a way to provide water and fertilizers. This would be quite a big engineering task. Maybe you can just spray it? Don't know how it would work with your kind of artificial gravity. In microgravity, it simply wouldn't work properly, and you need to engineer up some other way of getting soil moist. ]
[Question] [ I am thinking about a realistic Earth scenario following total economic/social collapse as well as mass extinction of humans on Earth (90%+). The scenario involved "stragglers" who try and eek out life in a classic survival tale, however it also needs to describe how the elite 1%s prepared and maintained life after the event. For the purposes of the scenario, it can be assumed that: - the event occurred in the current era of human civilization, and there is no hidden or magic technology available. - by wealthy, it is meant the extreme elite 1% who have small-nation like finances at their disposal. - they had engaged in any/all kinds of necessary preparation for an unforeseen event, and they survived this particular event. Although the nature of the preparation may vary. - they do not face any particular ongoing threat to existence, be it disease or violence, although they have lost the entire supply chain of sustenance and technology that advanced civilization provided. The basis to the question is that the extreme wealthy are particularly dependent on the supply chain of civilized society - be it advanced technology to skilled human labor, whereas the poor may already be adept at sustenance style living on the land. Do they give up all the trappings of wealth and join peasants on the farm? Do they barricade themselves in doomsday bunkers with 100 years worth of spam and hope their TV doesn't die? Do they join up with other wealthy and chosen followers and try and create a small isolated Utopian nation while preserving enough of the technological supply chain to keep living an advanced life (with a particular focus on environmental sustainability)? Or do they try and resurrect preexisting society by trying to establish a political class/system and bringing the broader economy alive? Any other possible scenarios. [Answer] It will depend on what caused the mass extinction, and over what time period. Let's say, hypothetically, that it is the most likely scenario - the walking dead debt-based financial system finally collapses, and at the same time, global warming starts to have serious effects. The 90% extinction will take a couple of generations in this scenario. So we are talking crop failures, mass starvation, wars over food and water supplies, diseases like cholera and typhoid making a comeback, etc. The elite will bunker in safe places for about 50 years. In those places, there will be electricity, modern medicine, etc, etc, etc. Pretty much normal middle-class Western lifestyle, except for the limited mobility because of the hordes of starving and diseased poor people outside the bunker. If they have enough time to plan and stockpile supplies, they may even be able to travel between bunkers in helicopters. They would be very well equipped with weapons, ammunition, and military personnel to use them. The average Joes outside, even if they did have guns, would run out of ammunition within a decade, so the elites would be like the Israelis in Gaza - using guns, tear gas, and rocket launchers against people throwing rocks. They might venture out to raid for additional stocks of canned food, but they would most likely have at least 100 years supply for population of the bunker before things go bad. (Plus hydroponic vege gardens, growing mushrooms on the recycled waste products, etc.) Once the dying-off process has cleaned out the bulk of the population, the elite would begin trading with the surviving tribes. Fresh meat in, medical supplies and metal goods like sewing needles out, and so on. Tribe life would be more difficult than life for the early American settlers, because there won't be horses, oxen, etc. Everything will need to be done by human hand. Poor areas in India and South-East Asia could provide examples of how this works. By the third or fourth generation, the elites would be able to emerge from the bunkers, because nobody would dare lay a finger on the "High Ones" that can save lives and provide magically useful manufactured goods. Anyone harming a High One would be shunned from human society, because if a tribe harbours a criminal, the High Ones won't help the tribe any more. In generation four or five, you might have enough rebels outcast to form their own, independent tribe, that hates the High Ones. Meanwhile, the elites will be working on re-establishing the basis of their technology, maybe going more for solar and wind power, because they are easier to deal with than fossil fuels. Vehicles would run on biodiesel. The army personnel from inside the bunker would be now be a hereditary warrior caste, whose good-looking daughters might marry into the elite, but not the sons (if we stick with today's cultural mores). The less physically-fit members of the warrior caste would do the janitorial level positions. There are a few possible scenarios - an ambitious military type might stage a coup against the elite, in which case the medical and scientific personnel would be lower caste than the military by generation four or five. Bunkers might start wars with one another, especially if the military are in charge. Younger members of the elite might start to chafe at the restricted life, and want to leave the bunker prematurely, or help the outsiders by giving them contraband. [Answer] Mass extinction of 90% of humans would send civilization straight back to the 19th century, but no further down. Humanity would lose the ability to make semiconductors, mobile phones, computers, automatic transmissions, and so on; but the knowledge to make steel and diesel engines and steam engines and electric generators and wired telephones is much too widespread to be lost; same for such fields of knowledge as law, economics, or medicine -- they won't have modern antibiotics, but sulfa drugs are not hard to make. After such an event the consequences will vary by country; it is indeed possible that some (small-ish) nations will degenerate into a sort of feudalism, but in reasonably developed nations what will happen is that those who think that they are wealthy will quickly find out that their material wealth has been nationalized, of course, just for the time being until the emergency is resolved, you will get it back, we promise. Financial wealth will of course be worthless. And here is the rub -- that fabled one percent elite who rule over all of us get their power from their financial wealth. They, it is said, control the banks and the corporations; but after a dramatic collapse financial wealth simply dissappears, it vanishes like dream. And actually a dramatic collapse is not needed: most nations will use any kind of perceived national need to disempower the elite. In the USA, top income tax rate was 90% or more from 1944 to 1963. In France, after WW2 they nationalized just about all major industrial corporations. Losing their financial wealth will mean that most of the members of the elite will find themselves out of the club, because in a world where money has no value (and actually there is no money, since the current electrons and paper or polymer bills will lose their magic) what counts is charisma, and physical strength, and luck. Why would anybody listen to Mr. Moneybags who was somebody before the collapse? What can Mr. Moneybags provide in exchange for goods and services? Bonus: In my opinion the best treatment of a sudden collapse of civilization is *[Lucifer's Hammer](https://en.wikipedia.org/wiki/Lucifer%27s_Hammer)* by Larry Niven and Jerry Pournelle, with the observation that it concentrates on a small area in America and makes no attempt to consider the wide world. [Answer] They would probably live like medieval Kings. Have access to the nicest accomodation,food,women and weapons. Have horses and servants. Be respected by everyone. [Answer] First, are you talking about one percent of the population or about the proverbial 1% who get mentioned in political debate? A bit of googling says that you need annual earnings of approx EUR 30k or a wealth of approx EUR 600k to make it into the top percent worldwide. (I'm not going to quote a link because I looked at several sites for a ballpark figure). So many towns and suburbs in the US or Europe might survive with most of their population. Probably a surplus of young male professionals and a distinct absence of single moms. People like that, what to they have? * They might own their home. * Some tools, some supplies, but not enough to last out a disaster. * **Organization skills.** They know how to make project plans, to stick with them when necessary and to adjust them when necessary. What will they lack? * **Bunkers.** Perhaps a storm shelter if they live in tornado alley, nothing more. * **Ammo.** They might have a gun, even in Europe where licensing is stricter, but they won't have enough ammo to defeat a zombie horde. * **Survival skills.** They spend their time at a profession, not hunting for food in the woods. [Answer] Their employees are the biggest threat or resource. Unless those guys are completely paranoid they will probably try to bring a few colleagues, friends, and most definitely employees with them to their bunkers. You will have some people for general maintenance, cooks, mechanics, hunters, mercenaries or private security, maybe even butlers and maids to keep their bunkers working in a decent fashion. However, as soon as the worlds truly ends money will have no value and if your rich guy used to be an asshole to the maid, then he might as well find himself shanked to death with an old toothbrush during the night, all his resources shared among his old employees. If they are completely paranoid and try to go alone into the bunker, then they will slowly go crazy from the isolation. ]
[Question] [ For those who have (for some unfathomable reason) not yet watched the HBO series or the 1973 original, Westworld is a robotic amusement park, populated by incredibly lifelike machines (hosts) where park visitors (guests) can go and indulge their thirst for adventure, or alternatively satisfy their darkest desires. Imagine for a second that such a place actually existed. At any given point, there would be many human guests and thousands of hosts in the park. In this Westworld-like place, human guests would be murdering robotic hosts on a regular basis, as would some of the hosts. The hosts are simply repaired, memory wiped, and placed back in the park. So far so good. The machines are prevented from killing or maiming the guests by programming directives, which I'm willing to accept, since machines could have built-in ways to identify each other. But given that guests and hosts are outwardly at least physically indistinguishable, how on earth can I get my guests to know not to kill each other? It can be argued that bullets in such an amusement park are made such that they cannot hurt humans, but there are explosives, knives, ropes, water, rocks, sharp sticks, tall buildings etc. **How can a no-holds-barred amusement park prevent its human visitors from killing each other?** [Answer] The explosives are simulated (remember there was manual human approval for the two small cigar explosions in the prison break episode?), so they are not lethal. Ropes, sticks, and just regular sucker punches and glassings in pub brawls are more likely issues. Especially if the alcohol is real. It is exactly the same problem faced by any theme park now - how do you prevent crimes on your premises? If someone is determined, it would be very difficult. You could posit a bio-monitor on each human guest, so that their vital signs can be monitored. After all, it's a kinda dangerous environment, and many guests may get hurt accidentally (falling off a horse, drunken stumble down the stairs, etc). Staff would want to be alerted ASAP if anything happened to a guest. You could also say that medical technology has advanced to the point where there could be a swarm of medical nanobots saturating the park, healing any guest who is sick or injured. It is not entirely clear that Westworld is enacted in physical space, either. The entire thing might be a VR simulation. [Answer] In the show, we do see that humans can get hurt to some extent, but not killed; that would suggest that it's not some form of VR situation. So, given this evidence I'll go ahead and assume that it's entirely physical and give a possible physical world option. It's not quite modern day, but we're not that far off. So, it certainly can't be a gun-end solution on the basis that people move; for example, a human diving in front of a host after a shot was fired. This implies that the guns themselves could be completely real and it must be a bullet thing. **How could a bullet damage something but bounce off something else?** They could be made from [programmable matter](https://en.wikipedia.org/wiki/Programmable_matter). Essentially, objects made from nano-robotics. This is an active area of research and has already had some very interesting results. The same also works for knives, ropes and virtually anything in the world. I.e. when the programmable matter detects that it may injure a human, it simply disintegrates. This would cause a little bit of harm, as they do in some scenes in the show, but is overall non-fatal for humans. **Bonus round**: There's also a lot of active research into 3D printable programmable matter. As seen in the opening title sequence, 3D printing is quite clearly a cornerstone of Westworld too. [Answer] How about regular old fashioned security guards on the premise? Guards who inconspicuously stay around the human guests or even acting as local in-world sheriff and just stop things before they escalate? This is even easier when guns are non-lethal (rubber with electronics inside that robot victim are programmed to react to) to humans. Or perhaps the humans can be provided with some device that tells them that the person they're interacting with is another guest. Say, a clip that vibrates when they're near another person or optional spectacles/contacts that highlight the robots with the press of a button etc. PS: I am still to watch the series and this answer is entirely based on what's mentioned in the question, so it's possible that I'm missing something obvious. [Answer] Seems pretty simple, you have all of the hosts programmed to intervene whenever two humans start to fight. This can be "in character" at first, then escalate to more and more "out of character" intervention (supposed enemy [to each other] hosts working together to restrain a violent human, for example). Presumably a human visitor would break character if threatened with violence, which would signal to the other human guest that their target was "off limits". There may even be a safe word all human guests are instructed to use if they feel they are in danger. If the guest persists in attacking another human, well, that is no different than someone going to Disney World and shanking a guest. I imagine that if someone wanted to recreate a serial killer fantasy where they would be attacking random folks with little or no warning they could arrange this with the park operators and be given some type of signaling (valid targets wear something specific or act a certain way) or they are isolated in an area with ONLY robot hosts. Pricey, but possible. I don't see how Westworld could 100% ensure the absolute safety of a guest, just like no amusement park, museum, or restaurant can do the same. A slim possibility of injury at the hands of another guest probably adds a lot of spice to the experience! [Answer] As @BryanMcClure notes, in the original movie we were told that the guns would not fire when pointed at someone who was emitting human body heat. Assuming the electronics of this were sophisticated enough, that would prevent the guns from killing someone who happened to be standing behind your intended target and you miss -- the computers would figure out that, if fired at that moment, the gun would hit a person, and refuse to fire. I haven't seen the TV show (I didn't know there was one until now), and it's been years since I saw the movie. But I always thought it was kind of dumb to have real guns at all. Even aside from the potential danger to the guests, why would you want your guests to constantly be shooting up your valuable robots? I think it would make a lot more sense to have guns that fired blanks and then just have Hollywood-style special effects to make the robots look like they bleed and objects you "hit" fall apart convincingly. Likewise I wouldn't have real knives or any other weapons, just make it all special effects. If you're going to let the barroom brawlers hit somebody over the head with a chair, you better be providing those special break-apart chairs they use in fight scenes in movies. Every possible weapon is Styrofoam instead of wood or rock, spun sugar instead of glass, etc. Of course if they'd used that elementary common sense for the park in the movie, then when the robots ran amok they wouldn't have been able to shoot anybody. Really another case of a movie where people do incredibly stupid things because if they didn't there wouldn't have been a movie. The robots run amok, shoot at people with blanks, the people laugh, call the people who run the park, the park technicians fix the robots and they give everyone a refund for the day at the park being ruined. The end. Anyway, even at that this would be a super-dangerous park. People could punch each other, hit each other with blunt objects, etc. I doubt it would be legal to create such a park in the United States today. [Answer] In the original movie the guns won't fire on any one with a heat signature. In addition the guest maybe required to were a band around there army or something similar so the can be easily identified. Your gun could be similar. In addition have the heart rate and location of ever guest monitored, and cameras everywhere, and police standing by to arrest any one who would try to hurt another guest. ]
[Question] [ Two ships planned to establish first human colony of 250 persons to Mars are transported by unknown phenomenon into distant planet that is barely habitable [link](https://worldbuilding.stackexchange.com/questions/59144/choosing-axial-tilt-for-human-habitable-planet-for-largest-temperature-variation). Left without a choice to return to Earth they must establish new home there. The Super Earth has: * Radius of twice the size of Earth * Magnetosphere * Surface gravity of 1.6g * One satellite similar to Mars * In the habitable zone of Orange dwarf, around 80% of Sun's mass * Axial tilt of 90 degrees, which causes extreme temperature variations * 2/3 surface of oceans & dozen of continents * Atmosphere with similar composition to Earth but larger surface pressure There's only simple life forms living on the planet (algae, fungi, bacteria...) that are most likely inedible for the humans. Humans would have to rely on aquaponics until they could produce plants that could live on the planet. How useful would be near future genetic engineers for creating edible plants that would survive on the Super Earth, considering colony resources will be limited? **Edit - Backstory** The two Marsbound ships were launched from the Lunar base and each ship carries 1000 tons of cargo which was considered useful for establishment of the permanent colony. Humans have already landed on Mars, and there is one small research station with few humans living on Mars. The phenomenon moved the ships in the orbit of the Super Earth, they could land there, on the Mars like satellite or stay in orbit if they prefer. As soon as they land their ships are useful only as shelter or building materials. The colonists will have to work with whatever cargo they have in their ships, beside whatever they could mine, fabricate, grow or produce. [Answer] ## **Genetic Engineering Would be Nice, But it Has Complications** While genetic engineering would help plants or humans adapt to the environment you describe, it may not be possible to engineer organisms under these conditions: * A Marsbound ship does not need GE technology on board. We can predict the soil and atmospheric conditions on Mars, so we have already made a list of plants to grow on Mars and how to do so effectively. Your people are prepared for what they "know" what will happen, not for this anomaly. * If the ship has the technology to engineer plants, which it does not need, your scientists will not have the genes required to make the changes wanted. To make a frost-resistant plant, for example, you need genes that cause resistance to frost. Your scientists likely won't carry a library of genes to splice. * Engineering people in space will not work. Microgravity conditions affect the human body over time, so trying to engineer and birth modified humans will result in babies developed for low gravity. These humans will not be able to survive in the 1.6g on the planet's surface. Basically, the short answer to your question is yes, of course GE would help, but it could not be done easily with what your crew has. ## **There are Plausible Ways to Grow Crops Without GE** Let's consider what your ships have on board to grow on Mars. We have grown the following crops here on Earth with Mars-analogous soil: * Tomatos * Rye * Peas * Leeks * Spinach * Quinoa * Others in separate studies This means these are some of the plants likely to be on board your ships. **Nutrients** Your planet has usable water, but there is no way of knowing if the native soil is hospitable. There are several ways your colonists could work around this: * Grow a couple Earth plants. On the small chance the soil is habitable, great! But as many commenters have said, this is simply not likely. * Burning native flora to alter soil composition. While this may not guarantee success, it will release what nutrients native species do contain, giving you another option to test with. This method is sort of a Pandora's box, as you could release either toxins or nutrients. Probably best to test on a small scale. If it works, which is possible, great! But it might not. * If all of the above fails, human waste can be used as fertilizer. Up until now, the colonists have been eating, so they must be producing waste. This method may not be appetizing, or sanitary, but if the situation is life-or-death, it will fertilize crops to a reasonable degree. Additionally, if your crew brought any antibiotics aboard with them, these could be used in the soil to sterilize or reduce the problems caused by the Earth pathogens. **Climate** Luckily, your colonists were headed to Mars. This is a huge plus for climate controlled habitats on this planet. Mars has extreme storms, and extreme cold, so our solution for the colonization of Mars is to farm indoors, and to water plants using melted native ice. This could apply to your planet with ease. If your ships contain the weather, temperature-resistant materials or structures we would bring to Mars, your colonists can plonk them down onto this new world and survive in them. No extra climate challenges imposed. **Challenges of Native Flora** If you are lucky, and the soil on this planet is drastically different from our own, the native plants will have different nutritional needs. This means competition is not likely; plants will stick to areas with the nutrients they need to use. If the soil on this planet is similar enough to our own, and plants try to inhabit the same places, removal should not be a problem. This is analogous to a farmer weeding a crop on Earth; while you could argue that making land hospitable means your plants have to compete to use it, invaders can be removed manually faster than they invade. **Challenges of Native Microorganisms** This is up for debate. While kingledion is correct that [microbial toxins](https://en.wikipedia.org/wiki/Microbial_toxin) could damage humans and plants, there is no evidence of compatibility between these organisms' toxins and Earth chemistries. Elements such as iron and sodium, for example, will not harm humans or Earth-endemic plants, but they may be the main toxin of choice to kill species endemic to this world. The likelyhood of whatever is used to disable creatures on this world being effective against organisms from Earth is slim; there are only so many things that can harm us. *Edited to match information provided in the comments. Previous answer was based on being optimistic when given probability; now based on fact and reason.* [Answer] **Incredibly useful.** We are genetically modifying plants to be hardier and easier to grow even on *Earth*, let alone on some rock in the depths of space. In fact, I'm not sure how you were planning to terraform *without* genetic engineering capabilities. You've already mentioned that there's bacteria native to this place, which might mean big trouble to your unwilling colonists. A bacterial infection could wipe out whole crops, and the Black Plague was also a bacterial based disease (not viral, which is the only reason I'm able to write this post right now). In short, those people will not only need to adapt plants and animals to survive there, but possibly also modify their own genetics. [Answer] # Not so useful Today's tools are actually not so bad, so we do not have to wait for possible future to be able to model the situation. Main problem is the knowledge what to do, which modification needed, what should be encoded. Problem to determine which set of genes will give us what we need. Level where it starts is designing live, not by testing what we have in different combination to see what will work. Make needed sequence, we can it for pretty long time now. Recently (year+ ago) I saw news about solution which actually allows to insert sequence in any predetermined(by matching sequence we define) place. We are pretty enough sophisticated at manipulating with genes almost today(or maybe today, do not track that). But knowing for sure what this or another gene is doing, or will do in this gene set - is a big problem for us. People working on that, but we far from perfection. And in this hypothetical situation, they should not lease some genes but create them for this particular environment. Equipment needed to operate with genes is not heavy, not bulky (kinda, not include all stuff for chemical production) - so it is not a problem for 1000t. But if we can use computers to figure out which combination to use (this is more future part) - it may need lot of energy and computing power which may be not expected to have in that situation, and it definitely will take time to calculate and time to test. Faster, easier and simpler solutions - hydroponics. I mean not adapt plants to environment, but create needed environment for them, specially as this environment very similar to what humans from those ships will need. If they are not able to create those environment for plants, they probably can't create for them self. If they can't eat those algae, fungi, bacteria because they are so much incompatible - I bet those algae, fungi, bacteria burn in same way as earth algae, fungi, bacteria will do - at least they have potential to solve problem with energy pretty fast. Although, if this live is so much incompatible with our, there should be no problem to grow plants. Chemistry for hydroponics is pretty simple, so soil can be just sand, add few boxes and hoses and ready. [Answer] **Very useful** but they need to be much better than they are today. They major potential advantage of genetical engeneering is that the spacecraft of colonists just can put the genetic code of many useful species on some durable medium to recreate them on the target planet. They don't need to have lots of living plants and animals on board. But: Today's genetic engeneers are not yet ready for that. They are more like hackers on the code of nature. [Answer] I don't know about anything else, but you would need genetic engineers to modify the humans that land there. Radius twice the size of earth would mean a mass tens of times bigger then Earths (I am to lazy to calculate now), and a gravitational acceleration significantly bigger than Earths. Also, the atmosphere would be very thick, people could not breathe that air. Actually I think that at this mass, the planet would be to heavy to be considered a rocky planet, and it would be a gas giant (a little on at that). As such, the humans could not survive there. But if it would not be a gas giant, if they would first go to the moon, set up there, build up a larger colony and then they would genetically alter themselves they could go on the planet next. So for this genetic manipulation you would need genetic engineers. And there is another problem. Normally you would send a ship with a lot of resources first if you go a short distance like to Mars, then a colony ship with only what is needed for traveling safely. This because you can wait to see that the first ship got there safe, the load was not damaged and the people have the equipment. If it fails you just send another ship with equipment. That way you don't risk the lives of the people with some extra heavy ship in one round. This is what happens with the ISS now, we don't send extra heavy rockets with all that the astronauts would need for the entire period with them, there is a stash there and it is constantly replenished by unmanned missions (which are safer in term of potential human loss). This makes your scenario more improbable, as the ship would not carry enough equipment. You would send such a complete ship only if it goes a long distance (to another system). ]
[Question] [ I have this dnd campaign set in a world where the only continent is a giant mountain with a mesa on top. I've made it "big enough for the top to be as large as Europe", but never went into details with my players. I was thinking, is there a way I could solve the problem posed by the atmospheric pressure changing dramatically as you go higher and higher on the mountain? Is it the only way to say "because magic world"? [Answer] # Turn the problem around, or ignore it No there is no problem that the air gets thinner as you go up the mountain, because if everyone lived there and evolved there, then those are the conditions they have been adapted to. There might be a slight problem in going **down** the mountain though where the air pressure **increases**. Ordinary air can become toxic under the wrong circumstances when it comes to pressures. But in any case, unless this aspect of physics is important to your world I would say: ignore it all together. Just assume that the atmosphere **is** right for humanoids to survive both being at the mesa and being at sea level, and that that the evolution of humanoids and mammals and whatnot **is** adapted to all these atmospheric conditions. Only consider this if it is important to your world, your storytelling and the game-play. Otherwise just do some hand-waving and say "This does not affect them, because the Game-Master says so". [Answer] If you want to attempt to explain it: **Lots of atmosphere!** Increase the world's atmosphere to the point where pressure on top of the mountain is normal. Problem: now the pressure at the foot of the mountain would be at crushing levels. **Big glass dome** Or a force field, or a magnetic field so strong it can (Warning! Incorrect science!) pull air molecules towards the mountain. Perhaps not... **Possible geo-stationary sattelite** Have a moon which is SOOOO big that it pulls the atmosphere into an egg-shaped shell around the world. This requires the moon to be geostationary (always above the same point) and to coincidentally always float above said mountain for some reason or another. (Let's not go into what would happen to all the water on the planet.) **Inverse earth?** The world might not be a planet! What if it is a big hollow sphere with the sun floating in the middle? Maybe the centre of gravity for the earth is off-centre due to one side of the sphere being really thick and heavy (there being a continent-sized mountain on it)? In this case the atmosphere would collect around the mountain and be thinner around other parts. Problem: no atmosphere on the other side. **Anti-Gravity!?!?** Maybe there is a moon or something that is a source of anti-gravity, pushing the atmosphere (by coincidence, of course) away? The result: Thin atmosphere on one side of the planet and think atmosphere on the other. **Weird shaped planet** Let me just draw a picture for this one: [![Weird shaped planet](https://i.stack.imgur.com/Dfi15.png)](https://i.stack.imgur.com/Dfi15.png) Problem here is you're going to have a big ocean acting like a moat which surrounds your awesome mountain... Still, its plausible if not easy to explain. **Or ya know... "Because magic"** The explanation for anything which cannot be explained. [Answer] If the mountain is small enough, this can be solved by climbing slowly, in order to trigger [acclimatization to altitude:](https://en.wikipedia.org/wiki/Effects_of_high_altitude_on_humans#Acclimatization_to_altitude) after few days, the human body can function normally in hight altitude. Additional, human in this world could be stronger than human in our world, allowing quicker adaptation or higher maximal altitude. [Answer] **Short answer** : Or your mesa is empty from all sort of life (except some micro organism) and if your crew wants to go up there they will need to be well prepared. Or your mesa is populated but there must be some construction (or magical device) that allows life up there (e.g. something like domes over cities and tunnel that links them). I think the reason you care about low atmospheric pressure in high altitude is because you want your mesa to be populated right ? So there are several consequences to high altitude that are not really suitable for life. 1. **The low atmospheric pressure** : This is the most obvious, as you go higher, the pressure of the gas constituting the atmosphere are lower. Imagine a balloon poked with little tiny holes that you put underwater, fill the balloon with honey (for example) and press it. Under a certain pressure, depending of the surrounding pressure, the viscosity of honey and the diameter of the holes, the honey will poor into water. This is exactly how dioxygen goes through your lungs into your blood. The more the pressure of the honey (the air in your lungs) is, the more dioxygen will go into you blood. Furthermore there is a certain limit from which the process will reverse, and the pressure of your blood will be higher than the one in your lungs and so you will spit blood and drown. The same thing happen with plants. So to allow life you need to keep a pretty high gas pressure in lungs (with a magic high pressure bubble around the mouth or so). 2. **The cold** : The low atmospheric pressure leads to a temperature decrease. This is not good for life. But, in a standard atmosphere, there is an altitude where the temperature is increasing when you go higher. On the Earth for example, at 20 km high, the temperature is about -60°C and about +5°C at 50 km ! So, if your mountain is high enough (the Everest is under 10km high), temperature should not be a problem. 3. **Solar radiation** : Our atmosphere also protects us from bad solar radiation. UVs (really harmful for living cells) for example are mostly filtrated by the atmosphere (and all the ozone layer). To allow life up there you need to solve all of this problems. Some people, animals or plants are fitted to live in high altitude (e.g high hematocrit level). But in really high mountain live is almost impossible (except maybe some micro organisms). I think a good solution to solve them all at once is to inspire from planet exploration/colonization, the problems are pretty much the same. So I would suggest a big dome (glass, energetic, magic, it's up to you) that protects cities/towns from radiation by filtrating the light, and with an inside atmosphere constituted with the outdoor air, compressed and heated. The connections between the towns could be made by tunnels or by well paid people that have suits to go outside. Another solution could be to replaces those domes by (natural ?) hermetic caves. Sources : [FRAGILITÉ DES MILIEUX ET ÉCOSYSTÈMES EN ALTITUDE (in French sorry)](http://trebla-mountain.pagesperso-orange.fr/flore/eco_alti.htm), [Interview MSG : la sentinelle météo de l'Europe (in French too, but with a really good introduction)](http://www.futura-sciences.com/magazines/environnement/infos/dossiers/d/meteorologie-interview-msg-sentinelle-meteo-europe-599/page/4/) [Answer] You did not mention how tall the mountain is, but if the mesa is significantly wider than it is tall, there are some factors that could make things more feasible. First, something that large could actually offset the center gravity of the planet. As air will fall towards that new center of gravity it should help a bit, with the odd side effect of the air being a bit thinner on the other side of the world. Second, remember that planetary gravity always pulls planets into a roughly spherical shape. That's part of the definition of a planet, that it has enough gravity to do so. Rock will bend under many miles of its own weight. It is likely that if such a geological feature were created, it would quickly settle into a different shape. At the edges it might appear only to be a raised mesa, but the outskirts would have actually been pushed lower, possibly well below sea level. Then while the edges of the mesa might be raised, the center would inevitably be pulled down. So as you travel inward from the edge your altitude is gradually lowered, even if it's too gradual to discern visually. If however you want the mountain to be hundreds of kilometers tall, and of consistent altitude on the mesa, I think the only other feasible solution is that the planet, as Aric Fowler suggested, has much more atmosphere than earth. Consider Venus for some inspiration in this case. At the surface the pressure is 92 times Earth's atmospheres and the temperature is a broiling 462°C, but 50 km up the atmosphere is about the same pressure as Earth's and the temperature is 75°C. ]
[Question] [ For certain categories of items, namely weapons, armor and machinery (that's pretty general, I know), how well would stone fare vs metal? Assume that any complications with shaping the stone are gone. As far as machinery goes, I would like to know about things as simple as door hinges, to things as complex as systems of gears, or even vehicles of some description. What about the hull of the vehicle? For context: I'm trying to build a world for a tabletop game, and it's going to be fairly high magic. In D&D, there's a spell called Stone Shape. In my world, wizards (or the like) with the capability of casting a spell like that would be fairly ubiquitous, so it's use could be very common. The spell can shape at most a 5 ft cube of stone, and into any shape (of the same mass of course), or even multiple shapes (the spell says the object can have hinges, and hinges are really two separate parts). The spell is instantaneous. That, to me, seems like a good incentive to use stone over metal where applicable, as it doesn't take anywhere near the same effort to forge. So, given that forging from stone is instantaneous, and nearly effortless, and forging from metal is not, what sorts of things that we are used to being metal would be stone instead, if any? I didn't include the magic tag, because while magic is being used to shape the stone, any application of the stone is decidedly non magical. [Answer] Given that people used polished stone axes in the real world and went to a great deal of effort to make them, your wizards being able to knock out dozens for very little effort seems likely. [Neolithic stone axe industry](https://en.wikipedia.org/wiki/Langdale_axe_industry) If the magic takes no effort, these axes will be the cheap and cheerful ones that every peasant has dozens of. Metal axes will be expensive and high status objects in comparison. Pottery may take a hit. Why bother firing up a kiln and processing all that clay if a wizard can make you a stone jug or stone bowl with virtually the same properties? So anything made of ceramics - from your toilet to your roof tiles - could be made of stone instead. If wizards can do the shape stone thing to make the stone flow out of the way, then they'd be very popular with folks who want to do mining or dig tunnels through rock. Even if each wizard can only do 5' cube a day, they'll be burrowing through granite faster than a bunch of guys with pickaxes. Aqueducts, railway cuttings and canal tunnels will have gangs of wizards as navvies. Castles with thick stone walls will have teams of wizard sappers burrowing holes through their walls, undermining their foundations and generally wreaking havoc, unless there is some sort of anti-magic cast on the walls. [Lithographic printing](https://en.wikipedia.org/wiki/Lithography) is so named because it used limestone. If wizards can make this process faster or cheaper, books may be more common. Anything we make out of glass a wizard could make out of quartz (rock crystal) or other gemstones like amethyst. Most quartz will be semi-opaque compared to modern glass, but it will let a bit of light through. Making lenses from flawless clear quartz will be dead easy, so telescopes, magnifying glasses and spectacles should be another wizardly product. And crystal balls actually made of real crystal, obviously! [Answer] As a general principle, different materials have different properties. There's many variants of stone, and many variants of metal. Far too many to explore fully. However, there are some general trends you can rely on: * Stone is far harder than metal, but more brittle. This means that it totally ignores hits that may dent metal, but harder strike which may have left a large dent, or even a small hole in metal may shatter the entire stone because once stone starts to give, it gives all the way. * Because of this, stone things tend to have to be made thicker. A 1/8" layer of steel is effective in combat as armor. a 1/8" layer of stone in combat may be very easily shattered. This also means stone things will typically weigh much more, simply because they have to be thicker to have the mechanical properties. * Because stone doesn't bend, any errors in the final finish tend to lead to chips. Your stone hinges could work great if they're well polished, but imperfectly polished stone would quickly wear on itself and wear out. [Answer] Generally bronze age trumps stone age and iron age trumps bronze age. Not because it is easier to create but because the tools are stronger, better and typically longer lasting. It was easier to bash two stones together and shape them than to take said stones, break them down into smaller chips, heat them, and learn how to forge them into a metal. That being said, the metal end result was always stronger or more durable, and most importantly prettier! We humans love a shiny bauble! A stone item may last for a millenia while a metal one rusts and breaks down. But that is if the stone item is not used for millenia and just allowed to sit there. If you have a stone pickaxe and a metal pickaxe, the stone would wear out from use before the metal could rust. So speaking in tool use and moving machinery parts, metal would outlast stone. As mentioned before, stone is hard but brittle. We use metal tools to shape stone, so metal is actually harder. Because it is 'flexible' it doesn't shatter into pieces when hit too hard ( generally, I'm sure there are examples where it does). Stone items that do not have lots of moving parts or need to be moved regularly would most likely continue to exist in your world. Eg a stone table is simple enough but it is easier to move a metal or wooden table around the room than drag a ton of rock... Replacing moving parts made of heavier stone would be more frequent than moving lightweight longer lasting metal components. We humans are incredibly lazy. So while it may be cheaper to buy a stone cog once, having to buy and replace four 2ton cogs in a month/year would be repetitive, back breaking and annoying. It would still end up being cheaper in the long run to have things made up of longerlasting metal. Think of todays economy. People have the choice of buying cheap and nasty items that need frequent replacing or they can simply buy a single more expensive quality made item. So in summary. For simple things and quick fixes, your stone spell would work. But in the longer run, metal would still be used. Especially as this allows you to be independent of those wiley wizards! [Answer] If the wizard can alter crystalline structure of the stone or yet better, purify it, this could lead to ceramics made from natural minerals with interesting properties. Alumina, which is very widespread in nature, allows for metal/ceramics composites used in modern armour. Zirconia (found in nature as mineral Baddeleyite) is used for ceramic knives. Both can be used to prolong life of metal tools/weapons by coating them. For heavy duty bulk structural uses (hinges, bearings, hulls etc.) you need carbide and nitride ceramics, which aren't found in useful quantities in nature and must be made technologically or magically. [Answer] How about reinforced concrete? If you can introduce other material into the mix (like steel rods), you have a much more flexible range of substances to work with. Is silica rock? You can make lenses, mirrors and all kinds of interesting stuff. Also: elegant stone boats. ]
[Question] [ We all like hexapods, from the Centaur to the Griffin. A large problem with the realism of the hexapodal body plan is that there are not many reasons for a creature to have them and is still worth the energy they put into using them. What evolutionary benefits does a vertebral animal gain for having a hexapodal body plan? [Answer] Six limbs adds quite a few possible advantages that you can't get with four limbs. It allows each set of limbs to be specialized for particular purposes. Consider the following body plans: Centaur plan: Four legs for running, two arms for grasping, fighting, and using tools. Sure, we humans can manage with a bipedal stance, but it comes with a number of costs - diminished stability, back problems, and terrible childbirth. A grazing centauroid might be able to use their hands to pick or carry plants while keeping their head upright and on the lookout for predators. A predatory centaur-lion could run at full speed and use their front claws for slashing at prey repeatedly without slowing down. Griffin plan: Wings plus a catlike body. Great for a predatory lifestyle - sure, our tetrapod birds can fly, but they have to deal with awkwardly using their feet for standing, fighting, and holding things. Of course flying griffins would need to be small, like birds, but even larger ones could control their pounces in mid-air by gliding, making them better hunters. Pixie plan: Wings plus feet plus grasping hands. This would allow the creature to walk or run without burning the energy it would need for flight, fly when it needs to move quickly or reach high places, and use its hands to either fight or carry food back to its nest. Jumping plan: Frogs and kangaroos are great at jumping, but pretty bad at walking normally, and hopping everywhere burns a lot of energy. Imagine a vertebrate version of a grasshopper - it could use its front four legs for running normally while keeping its back legs raised, then use its back legs for jumping when it needs the extra speed. A prey animal with this body plan could also use its back legs for delivering powerful kicks to a pursuer's face while using its front four legs for running. Yes, six legs has some disadvantages - extra energy for growth and maintenance - but that doesn't mean they'd be useless or redundant. Using the same limbs for multiple purposes tends to mean they are less effective at their jobs than if each limb was specialized for one purpose, and more limbs means more capacity for specialization. If our early fish ancestors had six limbs for whatever reason, we'd be just as likely to re-purpose them as we would be to lose them. [Answer] Hexapeds are superior to quadrupeds and bipeds. Lets take the centaur as an example. Its 4 base legs provide lots of stability, which exceeds that of any biped. This is why we build tables with 4 legs, not 2. Also, 4 legged animals make up the fastest land animals on Earth. Humans, which are bipeds, use their upper limbs - arms - to perform fine manipulations. Other primates do this as well. Other advantages of upright hexapods is the ability to see farther. That is one of the reasons humans went from quadrupedal to bipedal. Although not in the same body shape as centaurs and griffins, [insects](https://www.si.edu/Encyclopedia_SI/nmnh/buginfo/bugnos.htm) are hexapods and make up up 80% of Earth's species and the most of the land's biomass. Having 6 limbs is working quite well for them. [Answer] Here are a list of the pros: * 6 Legs gives you greater stability. The organism would require less brain power to stop itself from falling over while moving normally, and would be able to keep 3 legs on the ground at any given time. Presumably, this would also give them greater traction. * Losing a limb wouldn't make them so handicapped. And these are the things that cancel out all the benefits and make it unlikely: * Extra weight and the need for increased cortical representation and muscle control on the extra limbs, which would presumably be load bearing, may be a problem * The heart would need to be stronger purely for the purpose of pumping blood through those extra legs, but since the legs taking a toll on the heart could cause this to actually not give any evolutionary benefit Unless your hexapod body plan was part of the ancestry of your species, it's super unlikely for this to occur. Imagine that for some reason, creature A (which normally has 4 legs) evolved an extra pair of legs. It requires a larger heart, and an adapted brain, as well as some nerve cord changes to control its 3rd pair of legs. How does this help the creature have more reproductive success? Sure, it's less likely to die in a rocky environment (stability), or it can run faster on plains (maybe), but how would this 6 legged creature reproduce with the 4 legged version of this creature? Mutations need many steps - it's unlikely for 2 legs to come out of nowhere, and there are no reasons why an extra pair of legs would make the creature better for reproduction. [Answer] They are still able to function if they loose a limb. For example, a primitive cripple might die if their leg were eaten by a lion because they couldn't hunt or forage any more. If a 6 legged (or 4 legged) animal lost a leg, it could still function about 80% capacity. ]
[Question] [ You have the wild hunt with demons, or faeries, riding antlered stags like horses. Any number of other stories based on that old tale, be it reindeer or creatures designed for fantasy world's. But what are the practical aspects that you need to take into account? I don't recall any stories mentioning anything. For example, I've seen many a picture of a stag running through a forest. To avoid getting its antlers stuck in the overhead branches, it throws back its head. So how do you ride the damn animal without being skewered by your own steed? What do you need to take into account when travelling? Is it just avoid low hung branches ie don't go into the dark forest or are there further aspects I haven't thought of? An additional related question, how do humanoids with antlers (be they real or just an antlered helmet) fight in enclosed places like tunnels? As an aside, while Santa has domesticated reindeer with antlers, he does not in fact ride them rather trusting to put a healthy harnessed distance between him, his sleigh and those antlers. EDIT: Thanks for your all your pointers. It made me redesign and add several things to my storyline. All the answers where helpful but I think the selected answer has to go to the most up-voted answer. [Answer] The Dukha people of Mongolia have mastered the art of doing just that: [![enter image description here](https://i.stack.imgur.com/csryI.jpg)](https://i.stack.imgur.com/csryI.jpg) The Dukha lifestyle revolves around the domestication of reindeer, which provide food and transportation. In addition, they hunt with eagles and trained wolves. Not really relevant to the whole reindeer thing, but too bad ass to go without mentioning. With regards to riding reindeer, they're a different animal than horses and will have different pros and cons. First off, reindeer, and most other forms of deer, are significantly smaller than horses, so they won't be as agile when they're carrying people. However, they're better adapted to life in cold, snowy areas. A reindeer won't have any trouble with snow or cold. With regards to riding through forests, running a mount quickly through deep brush is a bad idea for *any* kind of mount. Horses and deer alike are liable to break their legs if they lose their footing in dense brush. Your best bet is not to worry about training the deer to run through forests, but to train the *riders* to avoid terrain which might be potentially hazardous for their mounts. [Answer] Solving Practical problems: 1. The spines of antlers are mostly forward-facing for ramming into other bucks, so not a huge problem there. On the off chance there's a few spines pointing in the wrong direction, just cap'em. Big fluffy balls glued on the end, possibly? 2. The backs of stags/deer/etc. are actually pretty fragile compared to horses, so you'd have to be pretty darn light to be carried by one (or magically made lighter), or breed a deer with a pretty sturdy torso (which would impact the happy bouncy feeling people seem to like from the idea.) This might be able to be addressed by having a saddle that more rested on the buttocks and shoulders than the back. 3. The jumping... it may look pretty, but chances are it's going to knock you off. A Saddle should probably secure you in, not just be something to sit on. [Answer] Looking at horses for example, I believe that they were breed to be stronger which made them capable of being ridden. Likely, in your world, the same would have to be true of your stags/deer. There would likely be a major difference in the wild variety as opposed to the domesticated one when it comes to body structure. Likely, the two could probably still interbreed if the domesticated ones were released or visa versa should the breeder desire to get a certain trait introduced into their herd. Typically when we see stag/deer mounts, their riders are elven. Elves are typically thought of as much lighter than humans (as if their bones are hollow like birds, by magic, or etc.) and as such would be more suited for riding stags/deer from a weight perspective. Also, elves are often associated with woodlands (which is the preferred habitat for stags/deer) which makes the match easy to understand. The stags/deer are simply a resource that is in their environment. Horses (when wild) are typical of wide open plains which might make them inaccessible to elves. Humans are more typical in those environments as it is more conducive to agriculture than a forest which makes horses the obvious choice for them. With that in mind, any large animal capable of either carrying a rider or of being breed to carry a rider that is native to the area that the sentient race would likely be domesticated for such a purpose (great eagles, sea serpents, imaginary beast you create, etc.) Elves in most cases are considered to be either immortal (Tolkien derived) or otherwise extremely long lived. As a result of this, a breeder would outlive their deer (if the deer aren't magically immortal as well) and would have the time to breed the herd themselves for several generations to produce the desired mount. Otherwise, it would be a multi-generational job that would likely start out as a domestication project to create a breed that could be used as a "workhorse" until such time as they realized the potential of breeding the beast to act as a mount. [Answer] You asked for practical aspects, so: With the exception of reindeer/caribou, female deer do not have antlers. So 50% of your potential mounts present no problem. Hinds are, however, usually smaller than stags, so won't be able to carry as much weight. Stags shed and regrow their antlers every year. While the antlers are in velvet (regrowing), they are very tender. The deer settle disputes at this time by rearing up and 'boxing' or by a stamping kick with their front hooves. Speculating wildly... there might be certain times of year that stags are really reluctant to charge at your enemies head on, in case they bash those tender antlers on something. The Swedish Army once experimented with a 'cavalry' contingent of moose riders. [Here's why it failed](http://stockholm.headsaflamemedia.com/2014/03/08/in-the-1700s-the-swedish-cavalry-experimented-with-moose/) On the plus side, the riders sit far back from the antlers so can't get skewered! The 'throwing back the head as it runs' thing is deer body language. Stags without antlers and hinds do it too in some species. That posture might be a threat to another deer or a signal to a predator "Hey, I've seen you!". So not necessarily about getting antlers caught in branches. ]
[Question] [ **Edit:** Thanks for the answers I've gotten so far, and sorry the original question was so long and unclear. Here's a shortened and reworded version. I'm writing a treatise or research paper from the perspective of a biological or biomedical engineer who's been studying supernatural creatures in a world where they've just been confirmed to exist. These include werewolves, wendigos, Celtic fairies, jorōgumo, kitsune, etc. in a universe otherwise identical to this one. As a biologist with a cursory understanding of physics, what terminology might this character use in forming hypotheses about the underlying processes of these seemingly magical phenomena? For example, I imagine she'd define psychokinesis as "the mental capacity to influence matter through manipulation of electromagnetic interactions"; similarly, there would be a correlation between electromagnetism and the werewolf's shapeshifting power; the [mare](https://en.wikipedia.org/wiki/Mare_%28folklore%29) induces hypnagogia by messing with the brain's electrical signals. What hypothetical elements would a scientist use to explain how such things could be possible? An unknown form of matter/energy? The laws of another universe encroaching on our own? A fifth fundamental force? If the latter, is there any precedent for one fundamental force changing the behavior of another, e.g. the supernatural force acting on electromagnetism/gravity? The problem isn't so much that I can't come up with hypothetical sources of magic. It's that I'm not sure how readily a scientist with no prior background in parapsychology and woo would put forth such possibilities, or what other potential explanations they might come up with first before reevaluating current principles. [Answer] "Magic" or "Super-natural" is just another name for "[Things we do not know how they work, yet](https://en.wikipedia.org/wiki/Clarke%27s_three_laws)". Imagine we bring a polio vaccine 1000 years back in time. Behold!! I place two drops of this clear liquid on your child's tongue... and now it cannot become afflicted by polio. To them, it is absolute magic, because they do not know how this thing works. For us, it is mundane, because we have a clear understanding of how it works. And the reason we know this, is science. Science is actually kind of easy. It is a process designed to find out **how things work**. Note this specific wording: **how** it works. Not "why it works" or "what is it". To take a salient example: gravity. How does gravity work? Well it is easy: it makes stuff fall to the ground, that we have known for a long time. **Why** does gravity work that way? We have no clue. **What is gravity** exactly? Still no clue. But gravity is not magic to us, because we know **how** it works. Science works in the following steps: 1. **Observe**. What is happening? Can you find any patterns or recurring themes? Try to write down what the pattern is. 2. **Hypothesize**. Form an idea of how this thing works. You want to arrive at a situation where you say "If we have these conditions, and we do that particular thing, we should get this specific result". 3. **Experiment**. Set up the conditions, do that particular thing, and record the result. 4. **Verify**. Compare the expected result with what you actually got. Do they match?! 4 a. If "Yes", success!!! Publish your hypothesis, what you did in the experiment, and your results. Ask others to repeat the experiment. If they get the same result, go to point 5. 4 b. If "No"... try to figure out what went wrong. Was your experiment wrong? Or is your hypothesis bad? Start over from point 1. 5. **Enjoy fame and recognition** for making something that was Magic & Mysterious™ into something [understandable and mundane](http://tvtropes.org/pmwiki/pmwiki.php/Main/NiceJobBreakingItHero). Magic and supernatural things suddenly appearing in our world would not be exempt from this process... it is how we would go about trying to figure out how they work. And unless these things are completely chaotic and random, we would eventually figure out what the patterns are. EDIT: What would the implication be for "modern science"? Well, in short where would be **lots and lots of work to do**. These suddenly appearing things means a so far unknown and unexplored area of reality has suddenly opened up. Scientists everywhere would be overjoyed and thrilled because this is something entirely new. And with a bit of luck, it may even explain some of the old stuff better. What does it mean for the **knowledge** that we already have, and that we have gained through "modern science"? What if — for instance — there are gravity-manipulating creatures/things/entities/things-that-defy-description? Does that mean our old knowledge of gravity is suddenly null and void? Not at all. The only thing it means is that all our current knowledge gets a footnote. What used to be "This is how gravity works" becomes "This is how gravity works (unless some magical thing comes along and messes with it, because then all bets are off until we figure them out)". [Answer] I think the scenario was dealt with quite well in the fan-fiction "Harry Potter and the Methods of Rationality" (HPMOR): <http://hpmor.com/chapter/2> > > "You turned into a cat! A SMALL cat! You violated Conservation of > Energy! That's not just an arbitrary rule, it's implied by the form of > the quantum Hamiltonian! Rejecting it destroys unitarity and then you > get FTL signalling! And cats are COMPLICATED! A human mind can't just > visualise a whole cat's anatomy and, and all the cat biochemistry, and > what about the neurology? How can you go on thinking using a cat-sized > brain?" > > > Professor McGonagall's lips were twitching harder now. "Magic." > > > "Magic isn't enough to do that! You'd have to be a god!" > > > Professor McGonagall blinked. "That's the first time I've ever been > called that." > > > A blur was coming over Harry's vision, as his brain started to comprehend what had just broken. The whole idea of a unified universe > with mathematically regular laws, that was what had been flushed down > the toilet; the whole notion of physics. Three thousand years of > resolving big complicated things into smaller pieces, discovering that > the music of the planets was the same tune as a falling apple, finding > that the true laws were perfectly universal and had no exceptions > anywhere and took the form of simple maths governing the smallest > parts, not to mention that the mind was the brain and the brain was > made of neurons, a brain was what a person was - > > > And then a woman turned into a cat, so much for all that. > > > A hundred questions fought for priority over Harry's lips and the > winner poured out: "And, and what kind of incantation is Wingardium > Leviosa? Who invents the words to these spells, nursery schoolers?" > > > "That will do, Mr. Potter," Professor McGonagall said crisply, though > her eyes shone with suppressed amusement. "If you wish to learn about > magic, I suggest that we finalise the paperwork so that you can go to > Hogwarts." > > > "Right," Harry said, somewhat dazed. He pulled his thoughts together. > **The March of Reason would just have to start over, that was all; they > still had the experimental method and that was the important thing**. > "How do I get to Hogwarts, then?" > > > If you want to have your character investigate it you might be best off avoiding giving a full explanation for what's really happening underneath. Indeed almost anything you can think of will probably not be totally consistent. The hallmark of a scientist confronted with a problem isn't what they already know, it isn't even what they come to believe, it's how they go about trying to disprove their existing hypothesis. She might start out thinking that shape shifters are merely camouflaging themselves but then disprove herself by putting one on a scale while they change. The important thing is that the hypothesis she comes up with must be falsifiable and she should do her damnedest to test every hypothesis she comes up with trying to disprove herself every time. She doesn't even have to solve the problem. Merely approach it the right way. > > "Professor McGonagall," Harry said to the bemused witch strolling beside him, "can you give me two words, one word for gold, and one > word for something else that isn't money, in a language that I > wouldn't know? But don't tell me which is which." > > > "Ahava and zahav," said Professor McGonagall. "That's Hebrew, and the > other word means love." > > > "Thank you, Professor. Bag of ahava." Empty. > > > "Bag of zahav." And it popped up into his hand. > > > "Zahav is gold?" Harry questioned, and Professor McGonagall nodded. > > > Harry thought over his collected experimental data. It was only the > most crude and preliminary sort of effort, but it was enough to > support at least one conclusion: > > > "Aaaaaaarrrgh this doesn't make any sense! " > > > The witch beside him lifted a lofty eyebrow. "Problems, Mr. Potter?" > > > "I just falsified every single hypothesis I had! How can it know that > 'bag of 115 Galleons' is okay but not 'bag of 90 plus 25 Galleons'? It > can count but it can't add? It can understand nouns, but not some noun > phrases that mean the same thing? The person who made this probably > didn't speak Japanese and I don't speak any Hebrew, so it's not using > their knowledge, and it's not using my knowledge -" Harry waved a hand > helplessly. "The rules seem sorta consistent but they don't mean > anything! > > > [Answer] I have by chance, been studying the secular evolution of "magic" in several different cultures throughout human history. It dovetails quite nicely with my interest in scientific and technological history, because all science started as magic e.g. astrology --> astronomy, alchemy --> chemistry. --- ## Short Answer: Magic feels like magic, when its effects are created by communication with personalities that can arbitrarily alter material reality in some fashion. Magic feels like another form of physics, when no personalities are involved. Characters should have to learn specific words, rituals etc to evoke personalities and should often have to bargain with them. In your story, I think it would best to introduce magic first as apparent anomalies in materialistic measurements, something that could be explained with more materialistic knowledge and then gradually make the characters aware that magical personalities of some kind can manifest material effects, based on their the will or whim of non-material personalities. The effects on working science might be fairly minimal if magic is rare. Scientist would just define magic as a "special case" and go on. The social and political implications could be huge, however. Our political institutions and most of social assumptions in the modern West rely directly on the clockwork model of reality built by Descartes, Newton and other early scientist. If reality suddenly becomes arbitrary, even little pockets of it, a lot political, legal and social processes could breakdown. E.g. In a criminal criminal investigation, the investigators would first have to element a magical cause, i.e. the murder victim was killed by the Fey Wild hunt, or because they evoked the wrong magical personality and pissed it off etc all before they get around to the the abusive spouse. Engineers and programs might actually have to check for gremlins or build gremlin resistant systems. Police and military might have to adapt to fighting magical creatures or effects. We'd also start burning witches again, this time for valid reason. The ability to alter other people's minds, torment, injure or kill remotely with no obvious link between the attacker and victim, is utterly horrifying. Moreover, as long as the "witch" was alive, could anyone ever be certain they weren't casting spells from prison? Likely, witchcraft would become a capital crime. --- ## Long Answer **Background** It's important to not that prior to the 16th century at the earliest, no culture made a hard distinction between a materialistic "natural" world, the supernatural or the cosmology of the local religion. They were all part of the same set of phenomena and blended together seamlessly. Newton for example, spent a lot of time working on alchemy seeking what we would consider non-material magical results. Likewise, he saw the cosmology of his Christian faith as the basis for his "clockwork" cosmology. The key defining attribute that separates a magical world view and a materialistic scientific world view is the concept that the non-human and non-living world contains cognition, memory, desire, language and personality. In other words, **in a magical world, you alter that world by *communicating* with some non-material being** which in turn can influence the material world. In a materialistic world view, only living organism can be communicated with. Non-living objects, like rocks, are manipulated by apply various material effects to them e.g. heating, cooling, acids, smashing etc. In Western magic you have to periods or groups: the Pagan era which overlaps and was eventually subsumed by Abrahamic magic which is magic associated with the world models of Judaism, Christianity, Gnosticism and Islam all the religions that trace back to Abraham. The major pre-Abrahamic influences come Egypt and Summaria The major differences between the Pagan and Abrahamic magics lays in the immediacy of personality they communicate with. In Pagan magic, one evokes a specific non-material personality, which usually has specifically defined powers and regional range. Usually, dealing with the supernatural personality is pretty much like bargaining or trading with a powerful human being. Just as there are rituals for an audience with a king or priest, their are rituals for getting an audience with the entity. Just as humans won't do much for free, neither will the entities. In Abrahamic magic, the cosmos, materialistic and otherwise, is created and manipulated by specific words e.g. which came originally from the words spoken by the creator God. "And god ***said***, 'let there be light.'" Probably the best analogy would be that we all exist in a computer generated virtually reality, ala "The Matrix" and a magician is someone who knows the words to rewrite the program on the fly. **Note** that in Abrahamic word magic, speaking, writing or sometimes even thinking of the word/sign/sigil, triggers their effects because the "word" and its effect are one and the same thing. Therefore, the real words an symbols must be encoded somehow so that people can learn them, without activating accidentally activating them. Interestingly, specific personalities were reintroduced to the Abrhamic magical system by making specific angels and demons either the manifestations of or care takers for specific words or concepts of creation. The apocrypha of all the Abrahamic religions are full of complex hierarchies and relationships for these beings. Some historians classify the cults of Saints in Catholicism, each the patron saint of some activity or event, as form of personality based magic. **Modern Concepts** What most people think of as "magic" in modern West, even Wiccan and the like, is actually Abrahamic magic were the magic words themselves can create a direct effect. As well, in many stories, magic is actual a form of physics, devoid of personalities, were the mage tosses around "energy" in some form. I think we tend to shy away from true traditions of magic of any form because they are inherently linked to specific religious cosmologies. **Strongly Differentiating Magic from Materialism in a Contemporary Fantasy** 1) Don't evoke any concepts even vaguely materialistic e.g. energy. 2) Magic should violate fundamental scientific laws such Conservation of Energy, Conservation of Momentum or violations of Newton's laws of motions. ... most importantly... 3) There should be somewhere in the magic a definite personality of some kind. It can be a distant creator god who leaves knowledge of the words of creation behind attached or not to other beings, or it can be specific non-material personalities strongly attached to place or concept. In any case, magic is about speech and/or communication and nothing else. Again, the concept of programing a virtually reality program from within the program is a good analogy. The magician doesn't have to worry about energy or conservation or anything else. He alters reality by effectively rewriting the rules of reality on the fly using either the words that created reality in the first place or by evoking a being who knows how to do the same. For example, a magician would set something on fire by either 1) summoning a personality that can arbitrarily create fire or by 2) creating a spell/program that alters the properties of the target such that it burst into flames. All science is based on the Great Assumption i.e. everything that exist is subject to materialistic measurement and everything follows specific rules, even if we don't always know what those rules are. Scientific models are judge by their ability to predict the future evolution of the modeled system. All you have to do to throw a monkey wrench into scientific method is arbitrarily alter some aspect of the material universe by means that cannot be measured and which follow no rules other than the whims of the magician or supernatural entities. For example: Turning a human being into a sentient frog capable of speech, simply cannot be done under materialistic rules even if you evoke bizarre levels of quantum probability. The extra mass has to go somewhere, the movement and reconfiguring of tissue from human to frog would have to generate heat and you can't cram a human brain into a frogs neurology. If performed repeatedly and at will, that would make quantum fluctuations so incredibly improbable that a non-materialist effect would be more plausible than unknown materialistic effects. **But you still need the Second Law of Thermodynamics** The story paradox created by magic boils down to one of limitations. To have story, one must have conflict and struggle and that means that any magical elements must come with some kind limitation, usually attached to the material world, that limits what magic can do. Otherwise, magic either immediately resolves the problem or someone sneezes in the middle of a spell and causes the universe to implode. All our human perceptions of reality and story are ground in the 2nd law. Our intuitive model of realty says we can't get something for nothing, and that includes magic. Magic CANNOT use pseudo-physics like "mystic energy" but it must have a cost in time, knowledge, trade or consequence. Ideally, the cost should be utterly unrelated from the effect sought e.g. the cost of having a supernatural personality fix a flat tire would be to have the mage perform the "naked chicken dance" in public. The only linkage between the dance and fixing the tire is the entity who thinks it's funny to humiliate you. Well, you get the idea. [Answer] Of course many people would say that the supernatural does exist in the real world, and that this has been proven over and over. Some people have philosophical beliefs that lead them to dogmatically reject the evidence. And of course "supernatural" is a broad term, covering everything from vampires and zombies -- which I think almost every would agree are fictional -- to ghosts and pychic phenomenon, to a creator God. How can we reconcile the supernatural with science? I would say, easily. There could be forces at work in the universe that our present science does not understand. Three hundred years ago electricity was a mysterious force of which people had only the vaguest glimmerings of knowledge. Today it is well understood. Perhaps there is some force behind ghosts or telekinesis, that today is viewed as at best fringe science, but that three hundred years from now will be well understood, and people will build machines to detect and measure this force. You say that you doubt there could be another form of energy that is presently unknown but that our science has not yet detected. I'd say, why not? It is just within the last hundred years that two of the four known forces, the strong force and the weak force, were discovered. People didn't know that electricty and magnetism were two forms or perspectives of the same thing until James Maxwell in 1873. Consider human understanding of electricity before the 1700 and 1800s. People observed some mysterious phenomenon that they couldn't really explain, like lightning, some crude early batteries, etc. These things were on the fringes of science. Advocates of psychic phenomenon could argue that we're at a similar place now in their field: a few phenomenon that are poorly understood, and therefore difficult to reproduce and difficult to study. But someday there may be a breakthrough, some fundamental new understanding, and then people will look back at our day and say, "Wow, why didn't they see that telekinesis, the Bermuda Triangle, gamma radiation, and ball lightning (or whatever) are really the same thing? It seems so obvious." (BTW For the record, I sincerely doubt that most psychic phenomenon, like mind reading, telekinesis, astral projection, et al, are anything but hoaxes and muddled observation. But I try to keep an open mind.) It's easy to imagine phenomenon that are rare enough that people rarely observe them "in the wild", and so have no idea how to reproduce. There could be beings who are capable of acting in ways visible to us, but who generally do not. Perhaps they are trying to hide, or perhaps they just don't care whether we know they are around or not. This description could apply to ghosts, angels and demons, aliens, etc. For example, I came across a study once where the researchers set out to investigate whether people can really be healed of illnesses by prayer. So they got a group of sick people, and then they got people to pray for half of the sick people but no one to pray for the other half of the sick people, and compare how many in each group recovered. They found that slightly more of those prayed for recovered, but the results were not statistically significant, and so concluded that prayer does not work. Except ... they mentioned in their report that they only told the people saying the prayers the first name of the sick person for privacy reasons, and they said that they didn't think this would matter as an all-knowing God would presumably know who they meant. But by the same reasoning, wouldn't an all-knowing God know that this was all an experiment? Wouldn't he know that the prayers were not genuine expressions of concern for the sick person but a cynical test? And wouldn't an all-powerful God be capable of healing or not healing regardless of these fake prayers? He might heal only those prayed for to prove his existence. He might ignore the prayers and heal or not heal in accordance with his own plans. He might heal only those NOT prayed for just to mess with people and get a good laugh. I've seen other such experiments that claimed to find that prayer does work. They're all meaningless. My point is, if some supernatural phenomenon is produced by intelligent beings, it could be almost impossible to study scientifically. An intelligent being who knows that you are experimenting on him could decide not to go along with the experiment, or to deliberately screw up the experiment, for any number of reasons. [Answer] I don't know about much how magic works in the world, or what Supernatural creatures are in your world but here or if you have ideas of how a scientist might explain the supernatural. 1. Supernatural phenomena is caused or facilitated by a unknown energy source or particle that we have yet to detect. I know in your question you said that you think this answer would be unrealistic but remember we still can't detect dark matter even though we know it exists because we can see the results in our equations. That's why we called it dark matter because we cannot see or detect it with are instrument. Your scientists might try to use dark matter as an example in her Theory. 2. Intersecting in the universities. Natural laws that we see in our universe don't necessarily apply to other universes. The theory of other universes have been around for some time. You are scientists might theorized that the scientific laws of Another Universe was somehow superseding the laws of our own. While I think this Theory more likely personally, but I think a scientist would most likely choose theory number one if she were trying to explain Supernatural creatures. ]
[Question] [ Let's say a 1600s civilization is around, making lots of iron objects: guns, swords, farm implements, etc. One day those people vanish. What conditions would allow their iron implements to be *usable*, not merely recognizable, centuries later? (If it matters, say 200 to 600 years go by.) [Answer] Here are some of your options: **1- Boiled Water In Sealed Container** Boiling water removes the dissolved air in it and if you put an iron object in such water, it will not rust (6 grade experiment). But you will have to seal that boiled water container in order to protect it from dissolving air again (which would rust the iron). **2- Stainless Steel (Alloy)** This requires a carefully prepared alloy of Iron, Chromium, Nickel and Carbon. For best results, Molybdenum is also required, but since it is so rare, it be very hard for your people to have it and use it for preparing the perfect quality of the alloy. **3- Waxing** If you clean your iron objects and then carefully seal them with melted wax, they would remain rust-free. As sumelic mentioned in a comment, peat would work likewise. Wax would be a better choice than peat due to easy availability and it is much easier to remove too. [Answer] No oxygen and moisture. Actually *not that hard*. Something similar to [cosmoline](https://en.wikipedia.org/wiki/Cosmoline) would form an effective barrier. Basically something *thick* and goopy which won't react (too much) with iron, and reacts the right way with oxygen. This simply means they'd care about the objects enough to pack them away properly. I'd also add, hardened cosmoline is a *pain* to remove. I'm thinking tar might work, but can't really find any literature to it. Sacrificial protection might be another option - zinc was smelted in the 6th century and available in pure form in the 9th century. If folk noticed that it kept stuff from being damaged in contact with the metal, and valued it enough to store their iron objects with a *ton* of zinc ingots in contact with them [Answer] **High phosphorus content** in the iron they were using. This is something that could happen accidentally as a quirk of the local iron ore or this people's way of smelting it. The result is that as the metal weathers, a protective coating develops. Look up the "Iron pillar of Delhi" for further information. In modern times the same trick has been used deliberately to manufacture weathering steel which develops a thin patina of rust but which does not corrode further. ]
[Question] [ If I have a civilization of birds, could they, in and of themselves, create an infrastructure of "advanced nests"? Could they build weaponry? These birds, raptors, have an educational system, political, military, blacksmith, etc. So they can do rudimentary things like make a spear, or sew together skins, have a smelter and so on. They are more tribal, so I say "system" but it is not as advanced as humans. I did this before I had seen anything about Guardians of Ga'Hoole, and to me it is irrelevant, as I would like to know the plausibility. Would the birds require help from other species? They don't have hands like mice and rats do. [Answer] While birds do not have hands, they do have feet and beaks, which they use to grasp and manipulate objects. Their ability to perform any of the tasks you mentioned will depend greatly on the species of bird you have in mind, but many species of bird are relatively intelligent and skilled at manipulating objects in their beaks or feet, so they should be able to handle rudimentary tools. A problem I can see straight away is size and mass. Most birds that can fly are smaller than humans, and much lighter. This may not hinder them in a world of buttons and switches, but when they're expected to perform tasks like blacksmithing and construction with just muscle power, the little birds will probably struggle. You can solve some of these problems by incorporating many different species of bird into your society. Big birds like ostriches or emus have strong legs and necks, which they can use to do the heavy lifting, while the smaller birds can deal with the more precise tasks. There are many bird species that have specialized to do something very well; if you can put them to use in a place where they can use these specializations, I definitely think a bird society could work. But if all you have is one species of bird, especially a tiny one, then I think they're really going to struggle. [Answer] For inspiration, have a look at what Bower birds can do - they build houses with structural supports, a roof, even a little 'garden'. And they fill their houses with beautiful objects. There is a good Attenborough on this - <https://www.youtube.com/watch?v=GPbWJPsBPdA> Also, Crows are incredible crafty. They can use tools to solve 8-step puzzles. Again, there is a video on youtube - <https://www.youtube.com/watch?time_continue=3&v=AVaITA7eBZE> [Answer] "Real Life" birds are known tool users: [![enter image description here](https://i.stack.imgur.com/tXY6C.jpg)](https://i.stack.imgur.com/tXY6C.jpg) [![enter image description here](https://i.stack.imgur.com/K9edK.jpg)](https://i.stack.imgur.com/K9edK.jpg) I think it is believable to have an avian type species that use a combination of beaks, tongues, and talons to perform the manipulation that they require. Just remember, having been born that way they won't know there's any better way to do things. I also think the brains are more important than the quality of their graspers - but maybe that's just me. ]
[Question] [ This is a follow-on question from: [How alien can a language be - grammar?](https://worldbuilding.stackexchange.com/questions/30371/how-alien-can-a-language-be-grammar) Leaving the grammar behind we can look at how the actual words or concepts are transmitted. Almost all human languages are based around stringing together sequences of phonemes (sounds). There are exceptions (various sign languages for example) but those are used only when sound is not available due to circumstances such as deafness or a need for silence. So my question is what is the most believable ways, other than stringing together phonemes, that could evolve in a naturally occurring intelligent species? In other words how could they communicate with each other? Note that this would be the primary communication method so either should have an advantage over using phonemes or a reason why phonemes aren't used. [Answer] What is communicating ? Sending and receiving signals. How can I receive signals ? Thanks to my perceptions. What are my perceptions ? Humans have 5 senses. They can see, listen, taste, touch and smell. I think some sharks can feel electromagnetic fields too. Clearly, taste and touch are not so good to communicate as they are difficult to stimulate threw the distance. EDIT : I figured out thanks to IJoinedCozIcan that touch can be stimulated through distance with heat or vibration. So here's an all new spectrum of possibilities opened. As for the social-colony of livings communicating only by touch. Woaw ! END-EDIT On Earth, some species communicate with odours (Ants to locate foods, Dogs to mark territory), some others with visual signs (Bees "dance" to communicate, some humans learn Sign language), and some others with sounds (Human voices, Birds singing). Note that for Morse Code, it is possible to do it with multiple senses. (You can feel it by being touched, you can see it or you can hear it). Because light is faster than sound, visual signs may be a solution to communicate over long distances (some American Indians did it with fires and little clouds). The counterpart is that the others have to focused on the source, and some obstacles and noise can make the signal uncomprehending. The advantages of sound is that you hear it even if you don't focus on it. Drums can be heard really far. The counterpart may be that if you have multiple sources emitting at the same time, the messages will collide and potentially be incomprehensible. I'm ignoring telepathy, because it would be too easy. But that could be a lead. Thinking about robots, I can imagine some living communicating via radio or even electromagnetism. EDIT : (trying to answer the question more specifically) I understand your question "How alien can a language be-transmission?" as in "What is the less human but still natural way to communicate-transmission?" Since Human do communicate by sounds, if you still want some audio-based communication I would suggest you to use some Dolphin-like sentences (plus it works great in the water). While human communication is based on phonemes, I feel Dolphin use more something like elaborate whistling. [Answer] They could communicate using pigments and lights, such as some squids, cuttlefish and octopuses. Perhaps they have a particular part of their body that's devoted to showing off these constantly changing patterns, and different arrangements of colours/patterns/light intensities signify different things. This could be advantageous if they lived in a very thin atmosphere that doesn't conduct sound well, or if their primary sense was vision. Alternatively, if they had a heat-sensation system similar to the sensory pits of snakes, they could communicate by generating different intensities of heat from different parts of their bodies. [Answer] Asymmetric media might be interesting for a very hierarchical species, where the ascending communication is actually in a different medium than the descending communication. I'm going to suggest a transmission method where the regent communicates using near-field sound fields, and the minions respond with interpretive dance within that sound field. You might think of it like the bee waggle dance, only on a dance floor with a DJ changing the tune while you dance. Picture a species whose rulers have several mouths (or other noise making sources) and sufficient control over them to start setting up nulls in the soundscape in front of them, communicating not just with sound but *sound fields*. They communicate with the masses by sweeping these nulls around by varying the phase of each of their sound making organs. The workers are expected to dance around, keeping themselves in sync with these nulls. The message itself is encoded in the directions the nulls are swept. This communication mechanism is very secure because, unlike typical vocal communication, it depends heavily on near field communication that is simply not detectable at longer distances. You may be able to hear the strange screeching song of the regent, but the far field of the song itself contains none of the information content. I suggest this for a hierarchical species because there's a few neat quirks that show up. First off, there's a neat little feedback loop that lets the masses communicate back. If a minion is not right smack on the null (and, in fact, potentially having to predict ahead where the regent will move it next), the regent has fewer options to communicate, but the messages are easy to understand because the regent is basically shouting as their voice drags the minion this way or that (obviously failure to follow the voice is grounds for execution). However, if the minion gets good at staying in the null, there's room for a bit of choice. Obviously the regent cannot expect a minion to perfectly predict the regent's will before the sounds reach it, but the regent can observe how the minion positions themselves and gain insight into what the minion is thinking. In fact, this forms a 2 way communication remarkably similar to that of a human dance. The regent has complete control over where the dance will go, but it is the minion that adds the spice to the conversation in the form of its sways and shimmies as it communes with it master. This, of course, reinforces the hierarchy. The better you are in tune with the regent, the more you are capable of saying within the language. Sergeants and Lieutenants don't get promoted into rank as much as they simply demonstrate that they have the commune's interest in mind with their dance, so are permitted to say more. Rebellious individuals find themselves in fields of sound which have less room for interpretive dance (and in fact, the worst offenders simply cannot speak at all, for without the regent's sound field to dance in, they literally have no way of speaking). Inter tribal combat of this species can follow the lines Joe Bloggs suggested: smash. The two reagents begin generated competing sound fields and the minions all dance about (potentially with knives and other weapons) like they were salt granules on a [Chlandi plate](https://www.youtube.com/watch?v=YedgubRZva8). Combat ends when one regent can no longer produce a meaningful sound field. Interestingly, this sort of warfare would not be wasteful. Any minions which a regent could trap within their own sound fields as POWs immediately become minions in their own army, by the mere fact that they are dancing to the reagent's tune. Rather than killing a weak regent, opposing rulers might simply siphon off their minions with superior control of the sound fields around them. Also interesting is that it permits an opening for a promotion to regent. Once in a rare while, we get an opportunity to glimpse the dance of a lifetime. A minion whose dance has become so powerful that they are less of a minion and more of a suitor is in an intriguing position. Consider for a moment, the special case of an alien race with this provocative method of communication where even the minions have the organs to emit sound fields, but only regents are allowed to use them, causing atrophy in the minions. However, the skillset required to dance within the nulls is also the same skillset needed to learn how to practice using their voice without anyone noticing. If your song compliments the trills and tremolos of the regent's song, its hard to tell you're singing at all. This is a chance to exercise those unused vocal chords and learn how to sing on your own. The dance of ascension is breathtaking to behold. It starts as any dance does, with the only sign that anything special is about to occur being a strange sense of calm in the demeanor of the right-hand-minion who has been called to dance. The regent typically has no idea this dance has started until it is underway. The minion moves in provocative ways, communicating with the dance a vision for the hive which is initially in line with that of the regent, but soon diverges into its own story. At this point, the regent would love to stop, but it's too late. Her song has already brought a sense of awareness and energy to the entire hive as a side effect of dancing with the suitor. To stop now would undo all of her hard work to keep the hive together. She has to keep singing until she can subdue the suitor. Many times, this happens. The suitor tumbles off of the null, and in a heart beat the entire hive descends on his body and shreds it. However, on occasion, this simply doesn't occur. The suitor understands the regent's mind too well, and she simply cannot trap him. Then, something magical happens. The suitor stops moving. Or at least, perceptibly stops. Now the battle of wits begins. His most imperceptible movements are amplified by the shape of the sound front such that the regent *must* adjust her song to match his movements or lose control of her hive. However, the suitor seems to be one step ahead. Every time she tries to move the null off of him, his position is perfect to shatter the hive unity if she doesn't converge it back to him. They may stand ostensibly motionless for several minutes, her song crashing all around him, but never able to shake the null he has put himself in. Then, when she isn't listening, he begins his tune. It's much quieter than hers. While he's been practicing, there's no way to practice true combat volumes without someone noticing. However, this is not a song of brawn. Its a song of finesse. It slowly distorts the sound front around the other hive members who, energized, respond ever so slightly. Then, in a singular moment, the regent bows her head to one side, trying desperately to keep her minions in control under her field by shifting the position of her singing organs. But a head bow is one move within the minion's dance, and it leads to another, and another. The suitor stands still, as the regent once did, while the regent is forced to dance as a minion until she ceases her song entirely. In a show of simultaneity which would leave any drum line or army drill corps to shame, every minion rotates ever so slightly to attune to the suitor's song alone. He is now the regent, having demonstrated that his grasp of the need of the hive far outstripped the dethroned regent. She is now his right-hand-minion. [Answer] One potential that actually occurs in ant species: *Open, bloody warfare.* Well, not quite, but the interactions of a hive's contributing parts can fundamentally affect the way that a hive behaves. In common ants the emergence of a long-running threat changes the worker/soldier dynamic in the nest. In the instance of an emergently intelligent hive species, communicating with another hive is simply a matter of bodyslamming your constituent parts together to see what happens. Want to shout louder? Send more minions. Want to change your inflection? Use different minions. It doesn't matter if some die, they're replaceable. You can be in the middle of delivering a love poem, and to other species (say the monkeys in the flying tin cans) it will look like you're engaged in the most brutal form of warfare possible. This concept is actually explored quite well by Orson Scott Card in the Ender series of books. It seems that the buggers are hell-bent on destroying humanity when actually they're just trying to say 'hello'... So if you're a hive mind: Communicate via the medium of minion. [Answer] What about a species that communicated entirely in images? An image can convey a complex message much faster than sounds can ('a picture is worth a thousand words', after all); the reason we don't use pictures to speak is mainly because we lack the physiological ability to quickly create rapidly-changing pictures with our own bodies. An intelligent species that evolved from something with the ability to change color at will, such as an octopus or squid, might very well convey complex information through flashing images across their own skin. Such communication would not only be faster and more efficient than words, it would be much easier for another species to interpret. (They would probably have a very hard time imagining that creatures like us could communicate through *sound*!) [Answer] The most believable are probably the nearest of what human actually use, and can do. One possibility is to communicate by sound, but instead of using *phonemes*, use *musical notes*. Even humans can make the distinction between different pitches (and some can even recognise them on an [absolute scale](https://en.wikipedia.org/wiki/Absolute_pitch)). So you can simply replace words and sentences by melodies. One question remains, "why not both phonemes and musical notes ?". Well, for the same reason humans use musical notes in a very restrictive way when they speak. Note that it is hard to imagine a believable way to communicate other than with sounds, since it has many advantages : not directional, variations are easily to produce and you can encode a lot of information in short period. I think that the fact sound is not directional is the biggest evolutionary advantage, since it means you can inform all your buddy at the same time that there is a danger. [Answer] I don't think it is far fetched that an intelligent species might develop technology to intercept thoughts using an implant to the head and relay those via radio to another implant. The benefits could be so big that after a couple of generations, that species have both evolved out of regular speaking and culturally made speaking redundant. Also, imagine a culture where individuals are not allowed to speak to each other. They must speak to the MASTER who will relay their communication. Going above radio, what if some weird alien race had xray vision&emission&immunity, they could communicate via xray over walls, etc... [Answer] There is no end to what form an alien language could take - any kind of signal, sound, light or any electromagnetic wave, touch, smell, gravity waves, thoughts, gestures.. The only condition would be that the parts of the signal are somehow related to each other. Also, the composition of the signal can seem like totally random to an external observer. ]
[Question] [ I have a mountainous barbarian tribe that - for cultural and historical reasons - absolutely adores ambushes and surprise attacks. They'll go out of their way to set them up. They also vastly prefer melee combat over ranged. **What melee weapon would be ideal for these barbarians to use?** I'm looking for something that would have additional benefit during a "surprise round" type situation. If necessary they're willing to carry multiple weapons, one to use initially and the other the rest of the fight. Technology is medieval Europe (~1500s) and the barbarians are on foot. For the purpose of this question, assume they're ambushing units 50-100 well equipped and well trained soldiers from the same tech period. They rarely have numerical superiority and will do hit-and-run attacks in those situations. [Answer] Given enough time to prepare, even a small, low-tech group of barbarians can wipe out a heavily armed army of trained soldiers. Surprise is a massively useful weapon; no matter how well armed or how well trained a soldier is, if he is running around screaming and wetting himself, he might as well be a rabbit. So, you want to make this highly trained army into an army of rabbits. Fear and confusion are your best allies, and the best weapon to cause fear and confusion is fire! Fire is loud, hot, bright, and unpredictable. It's easy to find, and hard to fight. However, you also want plenty of theatrics. The more unexplainable events there are, the harder it will be for reason to overcome uncertainty, and the easier it will be to scare the life out of an army. I know you just wanted melee weapons, but sticking with a motif makes it much easier to plan in the end. First, costumes. You need three different costumes: Fire, Smoke, and Ash. * "Fire" will be the hardest to design. You'll want thick hides, pitch, and your biggest warriors to wear them. Paint the warrior's face and arms with dark mud; not only does it look scary, it also protects from flames. Paint the hide with pitch. Just before battle, light the pitch on fire; the warrior doesn't need to have the hide on long; first impressions are key. A towering warrior wreathed in flames is extra freaky. Pitchforks and tails would be a huge bonus. * "Smoke" is easy. Those men should have the same dark mud, but no burning cloak. Instead, they should wear smoke bombs - smoldering rags or lit bottles of saltpeter and sugar. Lots of smoke, no fire. * "Ash" is the easiest yet; their faces, armor, and anything else exposed should be painted bone white. Chalk dust is perfect for this, as is real ash. Second is weapons. * Smoke and Fire costumes should have torches and darkened melee weapons, capable of doing a lot of damage in tight quarters. Weapons like axes, short swords, and maces would be the best choice. * Ash costumes should have short swords, knives, or other very-close-quarter weapons. Third, prepare the ambush. Find an area you know the enemy will be marching through. You'll need about four hours to prepare. If you skip the trapdoor holes, you could probably get ready in as little as an hour if you have the materials available. Dig shallow holes in a field, glade, valley, or flat area, enough for approximately half your group; each hole should have a wooden cover and enough dirt and grass to hide it. Place one man in each hole and cover it up. Then, spread a mixture of dry grass, dry leaves, and fuel made from animal fat over the field, careful not to get any near the trap doors. Added bonuses would be "rocks" made from balls of pitch and flour, wax, or even pinecones - anything that burns hot, bright, and/or with lots of smoke. Fourth... wait. When the army approaches, with just a few well-placed touches from hidden torches, the field becomes a wall of fire. The dry grass burns quickly, lighting the animal fats and pitch; it will also create clouds of smoke. Once the enemy is distracted by the flames, attack with the Fire and Smoke warriors, pushing the enemy back into the flames. Finally, once the flames begin to die down, the Ash warriors under the trapdoors can leap out and join the fight. Once the fight is over, burn any evidence, including bodies; leave nothing but ash. "Bored from our long march, we were glad of the soft grass beneath our feet. Suddenly, someone at the edge of the field began shouting - fire! Faster than a thought, the dry grass at our feet burst into flame! At first, we tried to stomp it out, but it spread faster and hotter than we could bear, and the field was soon a burning inferno! I had barely scrambled to the edge of the field when I saw the first of the demons, huge creatures with blackened faces, wreathed in flames, swinging burning brands, and screaming in an unearthly voice! I dove to the ground and lay as one dead as the demons cut through my comrades. The demons drove my countrymen back into the fire, laughing at the screams of the dying. For a brief moment, I found hope as our soldiers pushed the hellspawn back, but suddenly the very earth beneath our feet broke open, and warriors of smoke and ash leaped forth! I ran, somehow escaping in the chaos, but I was the only one; the rest were dragged down to hell. When I returned, hoping to find survivors, there was nothing left but ash and bones..." [Answer] First, both mountains and ambush tactics heavily favour missile weapons. The traditional type would be slingers. Mountain folk have traditionally used slings to defend their herds against predators and to hunt small game. I'd suggest only having the warriors charge in for melee, and have the rest of the people use slings to soften the target and keep them disorganized. Since slings are cheap and efficient and useful during peacetime there is really no reason not to use them. Similarly rock slides are a traditional and effective ambush opener in mountainous terrain. No real reason people fighting for their lives would skip using them. As for the "honor demands face-to-face combat" I'd copy the Roman legionnaires. The equipment was not really that much better than what the "barbarians" used, but tactically the legions were suberb in both defense and assault. The assault part being the one you are interested in. Carry throwing spears (pila) or darts (plumbata), throw the missiles on assault to break the enemy formation. Then lead with your large shields and smash the enemy defense apart. Then kill the enemy with repeated stabs of your trusty short sword while keeping more or less in formation. I doubt your tribe could match the discipline and training of professional soldiers, but both the tactics and the equipment go back to the time when the Romans were just one tribe fighting other tribes on a mountainous area (grossly misleading; read comments). So you should be able to copy them pretty much as is. And copying the Romans on matters of warfare rarely gets you too much wrong. You could also copy actual mountain tribes, but like I said the terrain and tactics favors rock slides, traps, and missile weapons, which doesn't seem to be what you want. [Answer] Physical weapons are pretty irrelevant in this case, as your barbarians aren't fond of ranged weapons, though I do include specific weapon concepts as a portion of my answer. **The best weapons here will be fear/mystery/legend.** To do this you need to do a couple things. 1. Get costumes. Animal carcasses of vicious beasts making the men appear half man half animal could work. Black or white body paint could make them appear as ghosts/spirits. 2. Always win. Winning means not being found out. Your band must remain mysterious and feared. This is not to say you always massacre everyone but you should do some savage and significant damage before fading into the trees/mountains. A few crazed survivors help spread the legend and fear. 3. Strange weapons and technology. This supports the fear and mystery concept as well. If you are in a land of long swords use scimitars, or something else that is otherwise foreign, it adds to the exotic nature and mystery of the group. Big weapons (2H axes, swords, hammers etc) are and option as well, they can be downright intimidating before they are even swung. If you have some sort of tech, Greek fire as a historic example, that can help set the group apart. 4. Let time pass between events. Don't attack every caravan that rolls through your territory. If you can manage it you could let a couple years roll by so people start thinking its just a story or that the menace is gone. Then slaughter something...its good to have a calling card. Maybe stacking corpses a certain way or something otherwise brutal. If your group is so inclined (maybe they are rebels under an evil overlord) have them only strike at imperial targets...then your myth could even be celebrated by the local population as spirit guardians/protectors. [Answer] If they're going against equal sized groups of trained soldiers, their main weapon concern is that it will pierce the opposing soldier's armor. They probably expect professional soldiers to rally from a surprise given a chance, and you don't want to give them time to get their wits about them. If leaders start dying, rallying is much less likely to happen. As far as "surprise round" weapons, maybe some kind of flail would fit the bill. You can get a weight spinning on a chain or rope and build up a lot of energy to smash through a shield wall. They're also relatively cheap to make, which barbarians have to appreciate. Maybe the warrior elite would have something like a Chinese ball and chain weapon they would spin it up to build up speed and make for a really damaging first strike. They might fit whistles or something to the chain to make a creepy sound as the ball and chain built up speed just before the ambush was launched. Other than that, you could take an old trick from the Bible. Have each man carry a hidden torch (usually just a group leader had a torch) and suddenly reveal it in sight of the enemy. It makes it look like a much bigger group is attacking than in actuality, and can sow panic. [Answer] Sometimes the classics are the best: spears and javelins. Cheap, easy to make, disposable as needed. Both work well with shields, which are also relatively easy to make compared to better armor. Javelins make a good initial attack and also a deterrent to keep away pursuers. Tactics might be throwing first in silence, or, having one group yell and shout to draw attention before the second group throws their javelins at all the soldiers standing up to see what the commotion is. After the hit and run, the retreat is uphill with a reserve group throwing javelins to cover them. Spears make good reach advantage, and also allow you to push opponents downslope. If there's any narrow areas you can hold it well with the reach advantage. Spears can allow you to target mounted soldiers or deliver nasty wounds to the mounts themselves. Spears also don't require a lot of metal. [Answer] You say the barbarian tribes are at the same tech level as the groups of soldiers, but smelting and working ore is hard. Not just hard to physically perform, but hard for a small community (like that conjured up by "barbarian tribe") to support. Therefore, scavenged weapons and tools repurposed as weapons (or at least materials) will be very attractive. The swords carried by the heavily armored soldiers will likely be nearly-useless against them, as has been mentioned, but they can be reforged much more easily than fresh ore can be smelted and made into a weapon. Some of this is mentioned in other answers, but I think particularly attractive weapons would be the mace, the hammer, and the military pick. These weapons are all likely to do well against armored opponents. Surprise renders less-valuable the key advantage of polearms (like the spear, but there are better variants incorporating hammers, axes, or hooks against armor), which is reach. A spiked shield would be an excellent ambush weapon, though fewer spikes (1-3) would be much better for defeating armor than a shield-of-nails approach. A single, tapered central spike is probably optimal because it is easiest to withdraw from a defeated foe's plate, and minimizes risk of losing your shield at first contact. For a ranged weapon, though you didn't mention it, the [atlatl](https://en.wikipedia.org/wiki/Spear-thrower) is a fantastic choice for defeating armor. The ranged armor penetrating potential isn't matched technologically until the advent of the crossbow, and the chief disadvantage compared with the pullbow (the weight of ammunition) is actually an advantage in the case of armored foes. [Answer] The following, which are variations on the theme of tangling up and distracting opponents, and sowing more confusion. * Nets with weighted hooks on the edges * [Bolas](https://en.wikipedia.org/wiki/Bolas) * Jars of some kind of oil & hot pepper combination that breaks when thrown and splashes everywhere, gets into eye holes and crevasses of armor. I.e., medieval tear gas. * Arrows that scream through the air - [Kaburi-Ya](https://en.wikipedia.org/wiki/Ya_(arrow)) **Edit:** Ok, right, you said they prefer melee to range. They can throw any of these ahead of them as they charge in; where, naturally, they will use their favored [Hammers of Doom](http://www.shutterstock.com/pic-269140328/stock-vector-cartoon-mallet.html?src=O-sp0G9dZK6zzRCxjqx6Ww-1-4) :D :D [Answer] [Bolas.](https://en.wikipedia.org/wiki/Bolas) Previously used in hunting, bolas can entangle a surprised enemy and extend the length of time they're caught helpless. In a situation where you have only a few seconds to decimate an enemy, extending the time by immobilizing them increases the chances of succeeding. For melee style weapons, consider weapons that extend when swung. For an idea, see the [League of Legends character Jarvan IV](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CB8QyCkwAGoVChMI1Y6g37WcyAIVhB4eCh0fZwg9&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DRgOdf3x24qA&usg=AFQjCNFokYj6W5IDrUk6Ij1oKtXQy_MeTA&sig2=smZNFFLJz38m5EZVbXe-Mg&bvm=bv.103627116,d.dmo). His lance, when swung, extends outwards roughly two feet allowing him to puncture his target from a farther distance than usual. Similar weapons would be great for chasing or initiating an attack on a surprised enemy. [Answer] **Hammers or other concussion weapons** will be preferred melee weapon as hammers are capable of concussing an enemy soldier through plate, mail or leather armor. Unlike piercing weapons where the point can be wedged into enemy armor thus unavailable for defense or attack till it can be worked free, a hammer just hits really really hard either breaking bone, deforming armor or causing severe bruising to muscle and flesh. Perhaps a dual wield approach, with a hammer in one hand and a short blade in the other. The hammer provides the armor-defeat capabilities while the short blade can be used to exploit openings in enemy armor. It's a shame that this is only about melee weapons since building ambush traps can get pretty terrifying. ]
[Question] [ I'm designing a medieval/renaissance world economy but I don't know what resources to consider when it comes to medium or long distance trading. I'm not asking for specific resources that are valuable, I'm asking what makes them valuable. **What are the characteristics of resources that get traded over long distances?** This question is based on the suggestion of [dmm](https://worldbuilding.stackexchange.com/users/9122/dmm?tab=profile). [Answer] **A medieval period long-distance trade good needs to be compact, resistant to decay, valuable at destination and refined product.** The less a trade good has these four characteristics the less likely it will make a desirable long-distance trade good. In the medieval period, ships or caravans were the only ways to move trade good around. This comparatively small payload capacity to modern cargo ships has severe implications on what can be traded and how far it can go. **Compact** If a trader has the choice between two trade goods of equal value per unit, one takes up 0.1m^3 and takes up 1m^3, he will likely choose the former for his journey. He can sell one of the latter items or 10 of the former items. His profit margin will be much higher with the former trade good. **Resistant to Decay** A loaf of bread won't last more than a day before it becomes unfit to sell to someone who isn't starving. Fresh fruit shares the same spoilage attribute. On the other hand, cloth won't rot unless it's allowed to get wet and stay wet. Wood and iron also don't rot/rust if properly protected thus allowing them to be shipped much farther across the world. **Valuable at Destination** This seems obvious but is worth stating anyway. Something that may not be valuable to the exporter must be worth the price to the importer. If not, don't ship it. **Refined Product** *Iron Ore vs Iron Bars* - Iron ore is bulky and contains [~60% iron per unit of iron ore.](https://en.wikipedia.org/wiki/Iron_ore) While these percentages are high, refined iron ingots are 100% iron so they are 40% more valuable. This case is more a restatement of the compactness point. Aside from the bulkiness, a refined or manufactured product is generally more valuable than the sum of its ingredients. *Logs vs Lumber* - A single log is a huge irregular lump of wood that requires special equipment to handle. While some wood importers will want the raw log, many others just want the lumber from the log. Thus, an exporter will be able to charge higher prices *and* improve shipping efficiency by turning the logs into lumber before shipping them. Also, lumber can be more compactly packaged. [Answer] Basically anything that is location dependent on its collection/manufacture. Silk was huge because the Chinese had a monopoly on a fabric that had many wonderful qualities. It could hold fine details, was very strong, could even be used as armor. Spices were big in Europe partly because they had bland food. But many spices were limited to where they could be grown, or how they could be grown. So the more desirable and difficult to acquire an item, the more people are willing to pay for it, making it more valuable for it to travel longer distances. You wouldn't pay to bring a potato from more than your local grocer (yes I know potatoes came from South America, how about a turnip?) because they are cheap and easy to grow (and weigh a lot!). You might go to a nearby city to buy a good tool (maybe a high quality sword). Maybe pay to bring something from the next door country because they have the best lute makers. So the easier or less desirable an item is the shorter the distance it will travel to its end destination. Horse manure tends to go from the barnyard out to the nearby field... [Answer] For example purposes, let's take a look at Maya trade over long distances. I will shamelessly pull my information from [here](http://www.authenticmaya.com/maya_trade_and_economy.htm). The Maya associated certain materials, such as jade, with regional fertility and others, like turquoise, with smoke. Both these materials were associated with their gods. I would suggest one aspect of a good's value could be derived from the local belief system, as we can see in the Maya. Maya traders made use of cocoa beans (CHOCOLATE!), which were a high-value commodity back in the day. The bean could be used to make chocolate, but it was also a prized currency. I would suggest that one aspect of a good's value could be derived from physical benefit; in the case of foodstuff, goods that last longer will have higher value than those that must be eaten within days. The Maya also conducted trade using Quetzal feathers, which were used for decoration. The feathers of the resplendent quetzal were rare and a critical part of Maya social structure. I would suggest that one aspect of a good's value could be derived from cultural benefit and rarity. *The linked site provides much more information about each of these trade goods and more than I have described here. The inquisitive individual is encouraged to continue their reading there.* [Answer] I think these have historically been the important points when it comes to the goods: * Low volume/weight to value ratio, weight tends to be more important than volume with overland trade. This makes "value added" produces, those that have undergone a lot of processing (especially processing that requires great skill), generally preferable to raw materials though spices are so light that even raw they're often still worth the effort. * Location dependent monopolies, silk in ancient Rome was only traded from China, Bluff Oysters in the modern era can only come from the far south of New Zealand. This kind of monopoly can and has allowed traders to name their price to anyone who wanted their wears *and get it*. * The available speed of travel is going to play a large role in what you can ship any distance; for long distance trade at more-or-less walking speed hard cheeses, wine, preserves and the like yes, meat on the hoof maybe it depends just how far away you want to go, fresh seafood no. * Reputation is extremely important regardless of what you're shipping, you and the goods you're dealing in must be well regarded by purchasers, a bad reputation can destroy entire markets (like tulips in 1636-37), even things like Gold aren't worth much when people don't trust the vendor to be on the level. With sea-trade volume and "stacking efficiency" become more important in the weight/volume to value ratio because you're hull is only so large and its shape isn't going to change so even if you can spare another 500 tonnes of reserve buoyancy if you can't get that 10kg bolt of silk in the space between the bulkhead and the wine barrels it's staying right where it is. Whatever and however you trade government tariffs, national border crossings (fees and border permeability), import license fees, cost and necessity of caravan guards, warehousing, sales venues, etc... are all going to play a role, you have to be able to get your goods to market and for a reasonable percentage. [Answer] In the olden days you have two ways of getting rich from trade. Bulk staples such as grain, ingots, wool etc,. and luxury items, jewelry, weapons, fabrics. Luxury items are best for small outfits, low volume, high profit. A luxury item can be anything that is not readily available in the home country and expensive. Assuming you're a small trader these are what you want to deal in if possible in order to really make profits. But they entail either high risk transporting or high initial outlay purchasing them for the same reason. For a robber gang they're expensive and portable, a shipload of grain is harder to hide, sell etc,. and would need a bigger robber band. The pros of staples are you're not taking as much of a risk, they're staples, you will have buyers for the goods, they can be split into smaller portions and sold easily. The cons are you need to move them in bulk which takes quite an infrastructure to accomplish. Intermediary traders would probably do a mixture, buy staples and speculate on luxury items. Thereby guarantee a profit from the staples for their hazardous journey, with the potential of making a lot more through sale of luxury items which take up much less room. ]
[Question] [ In the Middle Ages, countries are at war with each other and wealthy nations will often hire mages to aid in their battles. Especially during an intense combat situation on the field, both sides are charging into each other's defenses hoping to overrun the enemy with speed. The mages usually stand afar from the heat of the battle and cast their magical spells. (Both sides also rely heavily on catapults and handheld ranged weapons.) **Rule of magics** i) The magical spell can only deal 4 elemental damages (fire, ice, lightning and arcane) on top of physical damage to the enemy. ii) Enchanted armors can provide resistance to certain or all 4 elemental damages as well as physical damage. iii) Enchanted items can grant wearer the following abilities: * Able to heal from a non-fatal wound quickly * Greater endurance and stamina * Boost strength to lift or push object many times their weight * Ability to run at many times faster than their average times * Ability to cloak for a certain amount of time on command iv) Only a mage can cast magical projectiles to deal magical damage, they do this by weaving hand signs with or without an incantation. e.g A fireball requires a certain sequences of hand signs in a specific order while homing fireball needs to be followed with an incantation. v) It requires two or more mages to manipulate a weather element such as to command a thunderstorm over the enemy territory. The size of the storm depends on the number of mages involved as well as the length of the incantation. vi) The shorter the distance between the caster and the magic, the stronger the effect. vii) No magic can influence another's will or action. viii) With experience, a veteran mage can quickly dispatch a small group of three well armed soldiers with ease. These group of elite mages consist of less than 1% of magic users. ix) Mages account for less than 1% of population. x) Enchantment on items is only active when the user is focusing, the effect is lost if that user is distracted, usually caught by surprise. xi) Fire element inflicts damage over time, ice based attack arrests the movement of the target for a specific amount of time and deals the lowest damage comparatively, lightning inflicts the most damage overall however it has a tendency to miss the target due to its speed and, finally, arcane only works against non-living things. xii) Mages can animate the dead(s) to fight in a battle, only arcane magic affects zombies. xiii) The harder the concentration (mage needs time to concentrate), the greater the effect of the magic. Thus channeling spells are generally the more powerful type of magic. **Note** Channeling spells requires casters to remain stationary for a certain amount of time while reciting/performing hand signs in order to cast a magical effect. E.g., raising the dead, the mage needs to perform a ritual spell which usually last thirty minutes to an hour to summon multiple zombies. These are some of the notable channeling spells: 1. Raising the dead 2. Summon thunderstorm, hailstorm, tornado, or any extreme weather phenomenon **Question** Since speed is of the essence in war, why does a mage still want to use a channeling spell during battle? [Answer] To me it seems non-channeling spells are akin to traditional firearms with more variety and channeling spells appear closer to artillery. Therefore, channeling spells become a complete tactical weapon. Such large tactical weapons are part of the art of strategy. Imagine, for example, you have 5 veteran mages. As you say, they can each take out 3 soldiers each with ease. If you treat them as soldiers, they would each be performing to their abilities as individual mages. Let's say if it takes 5 minutes for each of these mages to take out 3 soldiers each, in thirty minutes your soldiers will have defeated 90 soldiers (.6 soldiers per mage per minute x 5 mages x 30 minutes = 90 soldiers). However, if you treat mages and magic as a strategical weapon, you would have these 5 mages stay back behind the lines and complete a channeling spell. After 30 minutes, those 90 soldiers are initially still there, but now some immense magical event takes place. Let's assume that the enemy doesn't have any mages so we can observe the pure effect of magic (like an experimental control). If they summon zombies, they've effectively created unkillable soldiers that will relentlessly pursue the enemy, effectively winning them the battle, if not the whole war (if they really can only be killed by arcane powers, as you say). This is akin to infinite reinforcements. If they summon a a weather effect, they eliminate far more than 90 enemy soldiers in a fraction of the time. This is akin to an air strike or an artillery strike. By removing the mages from the battlefield, not only do you prevent them from being attacked in the middle of battle (ignoring the potential of a siege), you also incomparably and exponentially increase the killing potential of your army. Two soldiers as infantry act like two people with guns, but put those two together in a tank and you have an armored behemoth that can annihilate far more than two machine gunners combined would separately. [Answer] Channeled Spells would be Extremely powerful in war. No battle ends in seconds, and big battles may last for hours in the right conditions. That being said, There are 2 main uses of these kind of mages i can think of. The first and best use is for surprise attacks. Imagine a Medieval army camped out in tents for the night in a field, resting for the battle to come the next day, when suddenly a Thunderstorm rapidly forms right above them, or better yet, a Fire Storm. If its fast enough, The army is going to take casualties while the mages would likely take none. The mages would have a lot of time to freely concentrate and cast their spell with a few elite guards to keep their presence a secret until it is too late. If 10-20 Elite mages can form a thunderstorm in under a minute after channeling for any amount of time, then you only need to keep a small group of people hidden for that time which is not unreasonable in most cases. The second is in the battle itself. Mages would effective be treated like Catapults or Trebuches. They are in the back away from the enemy lines for safty, and they cast their best long range channeled spells. Mages with channeled Spells are artillery themselves effectively, as it takes time to attack, but attacks can kill many if aimed right. Both of these assume the Elite Mages Channeled Spells are extremely powerful. If the Storms can not be controlled at all or kill at least a handful of enemies, then there is little point for having mages in the fight at all. They would be relegated to either enchanting armor and weapons before the fight, or be with the archers which can and frequently are quite vulnerable and not worth it. They would then be best used for elite subterfuge or infiltration missions only, probably as assassins or spies for their utility and ability to reliably kill small groups quickly. [Answer] To supplement the previous answers. If your mages can relay on maintaining effects, keep them in your castle to maintain enchantment on your army, giving every one regen/strength/speed socks (because nobody is going to stop and steal a pair of socks during a battle) [Answer] **Change the battlefield** Scouts arrive with the information about the enemy army and you start setting up the place where the battle is going to take place. Use your mages to change the terrain to reduce the efficiency of the enemy army. Examples would be: * Mainly Heavy Cavalry supported for some light troops and archers: Make snow, enough to stop any charge or the use of the heavy cavalry at any point. * Heavy armor footmans and light cavalry as support: Bring the sun out, the desert at midday. Cook them in their suits deplete their stamina, harass them to kill their morale. * Great archers with deadly volleys: Make it rainy and windy, water would turn the bows mostly useless and any volley would end up hitting even your own troops. Use them as a force multiplier for your own army, see what are your strenghs and what would work for you. I remember an example of using magic that took time to cast, was hiding an army in the bottom of a lake after casting underwater breathing in everyone. ]
[Question] [ Let's say aliens were trying to drop rocks on the Earth to kill us all. What could we do so we don't die? * Aliens are orbiting the Earth * They are dropping materials they have mined from the moon. * The rocks are fired from a high orbit, and they spirl inward. What can humanity do? [Answer] The best answer is to get higher up on the gravity well and blast their ships out of the sky. Defending from KE bombardment from the ground is very difficult, since the incoming rounds are generally very small and moving very fast (typical studies like [Project THOR](https://en.wikipedia.org/wiki/Kinetic_bombardment#Real_life_concepts_and_theories) were looking at tungsten rods about the size of broomsticks, so the cross section would be very small indeed). The rods would be best attacked by shooting down the carrying satellite or warship, with the second best option trying to hit them as they re enter and are still highly visible inside the plasma sheath. Remember, this is a "broomstick" sized object moving at Mach 25, so you'd better have good aim! Railguns firing clouds of pellets might be able to disrupt the incoming rounds enough to make them tumble and break up in flight, but you still have pieces of metal falling at random at high mach numbers, so you are not really that much ahead of the game. Improbably powerful laser weapons are another means of fighting back. At the [Atomic Rockets website](http://www.projectrho.com/public_html/rocket/spacegunconvent.php), there is some discussion about massive FEL Xasers which can fire deadly coherent beams out to a light second (almost the distance from the Earth to the Moon), but since this uses X-ray frequencies, the atmosphere would absorb much of the energy, and you would have a bolt of plasma running back to the laser emitter... oops! A massive laser weapon like this *in orbit* is another matter. The accelerator for the electron beam would be a racetrack over a kilometre in diameter, but with the amount of laser energy being deployed, you could vaporize the incoming rounds in space, plus damage the launching mechanism on the moon and even spacecraft out to the edge of the [Hill sphere](https://en.wikipedia.org/wiki/Hill_sphere#Solar_System) (while the laser is a Ravening Beam of Death (RBoD) out to a light second, it will still be dangerous out to a light minute. It just won't vaporize steel in microseconds like it does at one light second...) In a high enough orbit, the RBoD will be able to shoot "down" at enemy spacecraft and rounds, and also be able to cover a significant fraction of the Earth and orbital space. Three in orbit should cover the entire globe with some overlap, plus provide for mutual coverage (one shoots at incoming spacecraft to protect the other one shooting projectiles on the way to Earth). Having more is better, since even saturation attacks can be split between multiple battle stations carrying RBoDs. Once you have the ability to build these sorts of weapons installations in orbit, it is a short step to turning them from battle stations to battlestars and being the ones going after the aliens instead. [Answer] Most of the answers seem to be focused on offensive methods against the aliens in orbit, which would be a great way to stop the orbital bombardment, but are not strictly defensive measures. Some purely defensive measures to survive orbital bombardment: **Stay on the Move:** Depending on the targeting and deployment methods the aliens are using it could easily take the aliens near a full orbit (90 minutes at LEO) to move an impactor into a decaying orbit and toward an intended target. So you just need to move fast enough that you won't be there when the bombardment hits, you would likely want to be several hundred miles away depending on the size of the explosion (quite easily on par with large nuclear weapons) so a speed of 100s of mph would be necessary mostly limited to airplanes, something like flying Air Force One and not landing for an extended period of time. **Hide:** the Earth is big, so depending on the aliens agenda (are they here to exterminate all humans or only the troublesome ones opposing them) you may be able to hide. Large population centers are going to be pretty easy to see, but small bases located underground or with camouflage may work, or you could hide your operations around not target humans. This is potentially a lot easier if the aliens have limited numbers of ships or observation satellites, as this would limit the times they are overhead and able to observe. Another good hiding spot would be under the sea, submarines on the move would be hard to spot and depending on the depth and size of the aliens bombardment offers some shielding. **Dig Deep:** The response by a number a number of Earth governments over the last century when faced with potential large nuclear explosions was to dig bunkers, this could likely work as a defense against orbital bombardment as well. This also has the potential benefit of the hide option above if your bunkers are in hidden locations and difficult to detect from orbit. **Spread Out:** This is the internet style of survival, originally design to survive a nuclear war, have enough nodes that if one goes down the system survives. As noted above the Earth is big, and if the aliens have a limited number of impactors they want to deploy, having a dispersed population would allow some to survive even a large scale bombardment. Survival could be improved by not only disseminating the population, but also infrastructure to support the population as widely and redundantly as possible. Ultimately if the aliens are intent on humanities extinction and don't want or care about the Earth as a place to live an orbital bombardment could go to the level of melting the crust into a molten cinder which I don't think has any effective defense, but if they are looking for a limited victory you could likely employ some of these defensive strategies to save some population of humans. [Answer] Best bet, put a few nuclear tipped missiles on the Falcon 9, SpaceShipOne, A soyuz spacecraft, or whatever and get into orbit. Being at the bottom of the gravity well has us at a big disadvantage. [Kinetic kill missiles](http://www.globalsecurity.org/space/systems/kew-htk.htm) could also be effective. Basically a KKV doesn't worry about a warhead, and instead relies on delivering the kinetic energy of an object traveling at thousands of miles per hour to the target. As @WilliamKappler said, you can't just drop any old rocks down and expect them to reach the ground. You need something very large, with a high metal content, and preferably a metal with a high melting point. But the aliens probably know that if they can travel across interstellar space. They could probably grab a few of the larger asteroids and divert them toward Earth. It would be a be a lot easier than mining the moon for the right kind of materials, and it's worked a [few times before](https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event). [Answer] Why not just use the simple solution? Shoot a gun at the sky! I oversimplify, as it's obvious that a regular handgun round won't go into orbital height, but all you need is a device that will shoot large aerodynamic projectiles at a high speed. This would be relatively cheap (quite a bit cheaper than massive laser arrays), and there wouldn't be much they could do about it, short of starting to throw rocks at it. But if you make enough of those installations, in a matter of minutes, at least one will hit the enemy ship hard enough to cause a hull breach. This velocity doesn't have to be very high, especially if an explosive is mounted on the projectile, or just a sharp, durable tip. The only major concern about this is that they may start to bomb out the installations on the ground, but, as mentioned by Jim2B, there's enough clutter on Earth to hide the installations, until the moment of firing. In fact, the entire acceleration mechanism could be kept deep underground, with only a small bit poking out. This would be effectively invisible from space. Furthermore, you have to consider the "rock-paper-scissors" of aerial warfare: Ground anti-aircraft installations beat fighters (usually, or at least are armored enough that fighters can't do much about them) Bombers can reliably destroy ground installations, assuming you have enough so that a few can come close enough that if they are shot down, the explosion of their contents once it hits the ground it is still close enough to assure destruction of the target. Fighters can reliably destroy bombers, as bombers are meant to be anti-facility, not anti-plane, and fighters are designed to be anti-plane. Thus, a small force of fighter jets, even available by today's technology (though it depends how high they are) should be able to make it high enough to attack the "bombers", as fighters CAN make it to orbital height (they just need to get enough speed and then pull up). All you need is one or two fighters to make it within firing range, and then they fire everything they have at the bomber, which probably would be enough to breach the airtight hull. If that fails, ramming the ship at full speed while simultaneously detonating all the on board missiles would almost certainly be enough. [Answer] Would Aliens use rocks as a bombardment method, consider the following: (not mine, all credit to whoever wrote the original) Rocks are NOT ‘free’, citizen. Firstly, you must manoeuvre the space vessel within the asteroid belt, almost assuredly sustaining damage to the ship’s paint from micrometeoroids, while expending the fuel. Then the rock in question must be inspected to ascertain its condition. Should it pass muster, the ship must prepare the potential ordinance for movement. Finally, the ship may begin manoeuvring the warship to abut the asteroid at the prepared face (expending yet more fuel), and then begin boosting the stone towards the offensive planet. After a few days of expending a prodigious amount of fuel to accelerate the asteroid into an orbit to hit the planet, the ship may then return to the planet via superluminous warp travel and await the arrival of the stone, still many weeks (or months) away. After twiddling away the time and consuming food in the wasteful pursuit of making sure that the planet does not launch a deflection mission, they may finally watch the ordinance impact the planet (assuming that the ship does not need to attempt any last-minute course correction upon the rock, using yet more of the fuel). Given a typical (class Bravo-CVII) system, we have the following: Two months, O&M, Titan class warship: 5.2 Million Credits Two months, rations, crew of same: 1.2 MC Paint, Titan class warship: 2.5 MC Dihydrogen peroxide fuel: 0.9 MC Total: 9.8 MC Contrasted with the following: 5 warheads, “Planetary Destruction Grade”: 2.5 MC One day, O&M, Titan class warship: 0.3 MC One day, rations, crew of same: 0.0 MC Dihydrogen peroxide fuel: 0.1 MC Total: 2.9 MI Given the same result with under one third of the cost, will have saved a massive amount of money and almost a full month of time, during which the warship may be bombarding an entirely different planet. Bursarius Tenathis, Purser Level XI, Office of Interplanetary War Costings. [Answer] # Super massive laser weapons ### Lasers Since we are familiar with our planet and know how to tune our weapons to work on it, we can assume that a sufficiently warned humanity has the capacity to build and deploy soft UV laser weapons with the capacity to vaporize any ship it can hit. The range limitation will not be one of our laser's power, sensor targeting, or cooking ourselves with our own waste heat. It will be the limitation imposed [by light speed delays and alien ship maneuverability.](http://www.rocketpunk-manifesto.com/2009/08/space-warfare-v-laser-weapons.html) For a first order approximation, assume this to be several light-seconds to several light-minutes (it depends upon whether you assume high acceleration or low acceleration alien ships). Probably the laser weapon of choice will be the [free electron laser](http://www.projectrho.com/public_html/rocket/spacegunconvent.php#id--Laser_Cannon--Non-Bomb-Pumped_Lasers) tuned to fire beams in the highest frequency that passes out of the atmosphere with minimal absorption (probably something in the soft UV band). These installations will be over 1 km long and buried under lots of protective ground. Since once we fire the weapon, the aliens will try to target and kill our laser, it makes sense to have as many beam paths as possible under ground with many pop-up mirror turrets that fire the beam into space. The aliens will kill our cheap and easy to fix turrets but they won't know where the actual beam generator is. ### Missiles But our problems start after we zorch several of the alien ships. Assuming we don't manage to kill them all in a surprise attack, as soon as they realize near Earth space is deadly to them, they'll attack through asteroid bombardment staying well outside of our laser range. Our massive lasers have little chance of doing significant damage to their ships at the range of our asteroid belt and even less of actually hitting their ships. At ranges beyond a few light minutes, the only thing that is going to work are missiles, or even better [missile buses](http://www.rocketpunk-manifesto.com/2009/08/space-warfare-vi-kinetics-part-1.html). A forewarned humanity will boost these into space and hide them throughout the solar system, especially in locations we think the aliens might use for bases. A surprised humanity will just have to clear out near Earth space and launch them with the hopes that the aliens can't scrag our missile buses before they get out of the atmosphere and can maneuver. The missile bus will use Nuclear power propulsion (it will have to be [nuclear pulse propulsion](http://jim2b.blogspot.com/2010/11/the-case-for-space-viii-nuclear-pulse.html) or [nuclear salt water reactor](http://www.projectrho.com/public_html/rocket/enginelist.php#id--Nuclear_Thermal--Gas_Core--Open_Cycle--Nuclear_Salt_Water) based to get both the necessary acceleration and $I\_{sp}$). That'll be bad for our environment but at least we can fight back. The bus will contain multiple independent seeker warheads (probably kinetic but depending upon the planned engagement velocity, it may require nuclear warheads). During main boost and prior to the terminal engagement, the bus will provide propulsion for all of the seeker heads. As the bus approaches the target and prior to becoming vulnerable to counter fire, the seekers will separate. It is likely the bus and one or more of the seekers will contain high end seeker programming to integrate all sensor input (all seekers will contain sensors) and determine an engagement strategy for the whole cluster. ## But we're ignoring something We've been lead to believe the space is the ultimate high ground and that someone bombarding a planet from space has the advantage. [But there are some aspects to this we have ignored](http://www.projectrho.com/public_html/rocket/planetaryattack.php) and [even more things to consider](http://www.rocketpunk-manifesto.com/2009/06/space-warfare-i-gravity-well.html) 1. [In space, there's no hiding, cloak, stealth](http://www.projectrho.com/public_html/rocket/spacewardetect.php#id--There_Ain%27t_No_Stealth_In_Space) 2. But the "clutter" on the Earth's surface provides plenty of hiding places. 3. [In space, heat is a big issue and the more powerful your weapons, the bigger the heat problem](http://www.projectrho.com/public_html/rocket/basicdesign.php#id--Heat_Radiators) 4. On the surface, the whole Earth acts like a giant heat sink - meaning surface dwellers can use much more powerful weapons since we have, practically speaking, an unlimited heat sink. 5. [In space, **every gram counts** so ships won't have any armor](http://www.projectrho.com/public_html/rocket/basicdesign.php#id--Every_Gram_Counts) 6. On the surface, Earth installations can be well protected or buried. 7. [An invading force only "has what they can bring with them" and over interstellar distances, that won't be very much](http://www.projectrho.com/public_html/rocket/planetaryattack.php#id--Introduction) 8. The defenders have the all of the Earth and our tremendous industrial capacity to support war fighting. 9. In space, your sensor are limited to the size of your vessels (this directly affects the resolution and accuracy of your targeting systems) 10. As long as surface communications continue, we can integrate sensor data from all across the globe to get much more precise targeting data on the alien ships - we can see them MUCH better than they can see us ## Why Bother? Most of the details of how a space bombardment would proceed will depend upon the alien's objectives. As has been answered elsewhere, there are precious few reasons for aliens to bother coming here the first place. There are fewer to cause them to want to attack us and there are almost none that will cause them to attack us using anything but overwhelming bombardment from space. About the only ones I can think of are: 1. They want to use our industrial capacity (in which case, they will want to spare a significant portion of our industrial centers) 2. They want our real estate (in which case, they won't mind killing us or destroying our industry but will want to preserve the biosphere) 3. Then want to use humans as some sort of slave/warriors (in which case they won't care about the biosphere or industrial centers but they will want to spare a significant portion of the population) [Answer] # Firstly, why? Ask yourself what the aliens want to do. * **They're just plain evil and want to exterminate humans** - Orbital bombardment isn't the way to go. It is a useful supplement and a relatively cheap but effective way to destroy primary targets, but for widespread destruction you'll need something more thorough. Nuclear weapons are much better for the purpose. + **They want Earth's resources** - Now we're talking! In this case, this strategy is actually pretty good because it paralyzes the humans' abilities to organize an attack, so your aliens can swoop down and clear out any remaining humans with their futuristic laser weapons or whatever. # Be hidden. If you're well-hidden it could be very hard to make a precise strike. This goes very well with the strategy of building underground bunkers, which not only obscures your location but may also protect you from the blast if they do find out where you are. # Stay on the go. Their orbital weapons can't just drop out of the sky. It could potentially take a long time to align them and then deorbit onto Earth. Even when executed with *maximum* precision there is still a practical barrier to rapid strikes barring an absolutely massive network of orbiting weapons. As long as you constantly move, it will be very hard to kill you. # Hide. I'm not kidding. Earth is **really big**. It's hard for humans to perceive how big it truly is, but you can take my word for it. This works well with the underground-bunkers strategy because if you can avoid detection then there's simply no way for them to hit you. If you do detect a strike incoming, you still have a considerable amount of time to evacuate, so a highly mobile base will be a necessity. # Don't centralize. These weapons are great for knocking out a dense settlement fast. Avoid grouping together. Big cities cannot be quickly evacuated and can be wiped off the map with significant casualties easily. Instead, have a large number of low-lying bases. If this strategy is employed, avoiding conspicuous targets is even more important. # Salt the earth! This strategy is a little stupid, but before you evacuate all of Earth's former cities and go into hiding, launch thousands of pounds of debris into space. Pray that it creates a Kessler syndrome-esque cascade of destruction that makes launching orbital weapons very hard. Launching thousands of nuclear weapons and detonating them is also a great idea because it will increase the amount of protective shrapnel floating around in LEO, forming a sort of smokescreen consisting of hypersonic radioactive space junk. The downside is you may never be able to go to space again. # Ronald Reagan is your friend. During the cold war the Americans experimented with all sorts of ways to destroy ICBMs from space in an attempt to render them obsolete. One system that may be of interest is the [Brilliant Pebbles](https://en.wikipedia.org/wiki/Brilliant_Pebbles). They serve a similar purpose, destroying projectiles in space, and there is already a lot of research on it (though most of it is classified) so it could be very helpful in defending against the orbital weapons. There is also a myriad of other bizarre high-tech anti-ICBM technologies from the ~~Cold War~~ Star Wars era. These are all potentially great ways to destroy reentering orbital impactors. # A Side Note: Moon rocks are not the way to go. Blunt moon rocks burn up fairly quickly in the atmosphere. For an effective orbital strike ammunition, you'll want as much mass and velocity as possible. You can achieve both by making your weapons more aerodynamic, meaning more mass arrives to the surface intact and it loses less velocity to friction. You'll want long rods of something with high heat resistance like tungsten rods. ]
[Question] [ It seems I've been seeing a lot of uses for foam on this site, from a weapon to a spaceship defense mechanism. However, the details on what the foam is made of and how it works always seem lacking to me; thus, I worry that many of these foams are just science fiction. My question is **is there a foam that can be used to quickly construct airtight walls solid enough to keep humans out?** I imagine using this foam on a spaceship to trap the enemy, or alternately to fix hull breaches. Perhaps there is a fast-acting variant that can be used as a grenade to immobilize enemies. As it is a foam, it could be carried around much more easily than other wall-building materials, thus I could outfit my space marines with a few cans apiece. So, does this foaming material exist, or is there a theoritcal way to produce it? If so, how big would the initial substance be, and how long would it take to dry/harden? The foam need not be activated by air; on the contrary, it would be great if it contains its own reactants, and can be activated in a vacuum. It need not last; it should only be functional for a minimum of a couple hours. If it breaks down after that, that's fine. I would like it to be as strong as possible. If it can get to concrete levels, that would be best, but as long as it's very difficult for a human to burrow through that'll work. [Answer] Foam is, by definition, simply a lot of bubbles. **Bubbles don't work in a vacuum.** (Theoretically they do, but their behavior isn't interesting since they explode — emphasis on *explode* — immediately.) So this gives you a few upsides and a few downsides. I could see a viable 'cement-like' foam that hardens *because* the water or other liquid with which it is inflated immediately evacuates and vaporizes in outer space (e.g. when repairing the wall of a spacecraft) leaving only the igneous-rock-like matrix behind. @AndyD273 points out quite correctly that foam in a vacuum expands far more than it does in atmospheric pressure. But remember that this also means that you have far thinner bubbles in much more space, leaving you with a much weaker structure. Your wall material would have to be pretty (1) flexible and (2) strong to begin with, even before spraying. **But this gets more complicated when working in atmospheric pressure.** You're limited at the very *fastest* by the entropy-fueled diffusion and expansion of gas. This leads me to believe that a foam used as a quick-spray detainment weapon would need to have *highly* reactive gaseous compounds that are stored separately and then injected together into the foam as it's released, causing that sort of high-speed expansion you're looking for. (Side-benefit: **Such a quick expansion would either release or absorb a lot of heat**, depending on the mechanism. I could viably see your foam curing due to its own high heat, or freezing due to its below-zero temperatures.) --- Side-note: Anyone who's tried to use their hands to tear that foam insulation stuff knows from experience that, even though it's *possible*, it's an enormous pain to actually do. Easy to dent it, not easy to rip. **[EDIT]**: As @JDługosz points out, a foam in a vacuum can cure from the outside in... But that would lead to a pressurized interior. And [we all know what happens](https://www.youtube.com/watch?v=6V2eCFsDkK0) when brittle materials harden on the outside and leave a still-liquid, still-cooling interior... [Answer] The only foam I have much experience with is the expanding-foam insulation that comes in a spray can. From that, I find it fairly believable that you could plug a hole in the side of a ship with enough of it, though I'd imagine it would also unavoidably plug up a good deal of the interior of the ship. I've also unfortunately never been able to test it in vacuum. The hard part is making it durable enough to prevent tunneling. But if the human-to-be-trapped lacks access to digging tools, you might be able to keep them in by embedding hand-lacerating caltrops of some sort in the foam mixture. (Maybe these caltrops "grow" there through rapid crystallization?) There's not much point in digging a tunnel out of prison if you bleed out halfway through. Actually, if you use enough foam, and/or if it sets quickly enough, you could just trap the intruder like an insect in amber. That would also suffocate them almost immediately, unless they had a suit with an independent air supply, in which case you'd just have to wait until that supply runs out. [Answer] A foaming quick set epoxy grenade might work. Basically a weaponized, military version of this [expanding epoxy foam](http://www.prosetepoxy.com/custom_foam.html). Inside the grenade would be multiple chambers containing either the epoxy and the hardener. When the grenade triggers, a CO2 canister could cause the contents to mix and then be sprayed out in all directions through multiple nozzles. Foam in a vacuum seems to be [extra effective](https://www.youtube.com/watch?v=nDMySLjeyL0) as the low pressure causes the cells to expand a lot. If the epoxy was very quick setting then the cells probably wouldn't burst before it hardened. As @j6m8 points out, the cell walls would thin during the expansion into vacuum, which cause them to cure faster. The cells on the surface would burst, but when their walls collapsed surface tension would pull them back, thickening the outer surface, making it tougher and slowing the rate that the bubbles burst. To further weaponize it, mix a breathable or contact anesthetic into the gas mix or hardener, so that if the cells are broken open in atmosphere the anesthetic would be released and potentially knock out the target. In vacuum this wouldn't be effective, but the anesthetic could be switched out for something that could attack the targets suit like an acid compound, making it dangerous to attack the wall. [Answer] Shotcrete <https://en.wikipedia.org/wiki/Shotcrete> would probably be one of the best known structural foams currently available but there are certainly others available and is certainly able to set creating a gas tight surface and more than capable of keeping humans in or out. Good for making a permanent repair to that hole in your lunar bio-dome, probably heavier than you would want for a spaceship repair, and certainly too slow setting for foe suppression. For your emergency hull repair you would want a lighter weight substrate to quickly fill the gap and then use a heavier solid foam for the permanent repair For foe suppression just stick to sticky foam <https://en.wikipedia.org/wiki/Sticky_foam>. [Answer] Dental cement Spray a foam version of dental cement onto the assailant. Use a high-powered laser to cure it. Alternatively don't even use foam. Just spray them with the liquid and use the laser. You will cover them in a thin but incredibly hard outer shell that will immobilise them. [Influence of argon laser curing on resin bond strength](http://www.ncbi.nlm.nih.gov/pubmed/8397985) The main point about using lasers is (1) the ability to aim them (2) they act at a distance and (3) they cause fast setting even if the strength isn't increased. ]
[Question] [ On today's Earth, a mysterious cube of no light has appeared, about the size of a house. It's confounding, because it appears to have the mass of stone, by the way it is difficult to move and the impression it makes in the sand. It appears black, but darker - as in it doesn't reflect visible light. It is a little cool to the touch, and gives the viewer the impression of an optical illusion despite the temperature. I would like to determine a cause for why it has appeared near the end of the story, that isn't too *deus ex machina*. Fiction and some hand-waving is fine, but I'd like an interesting and somewhat believable explanation. EDIT (Additional Information): The background is that this is an object from outer space, which lands near Mecca and is soon an object of Islamic attention, similar to the rock of the dome, but absorbs light. [Answer] Vertically aligned carbon nanotubes do an awesome job at soaking up light. Carbon is black to begin with, and by making them stick up like tiny fur, there isn't a flat surface to reflect off of. And, actually, [we've already made it](http://guardianlv.com/2014/07/blackest-material-ever-invented-vantablack/). As to how they got there? That's really hard to say without writing the whole backstory of the object. But if you want something incredibly black, this is it. [Answer] Rex Kerr's answer is correct, but only part of the story. If the cube is expected to stay black for any length of time, it must incorporate some (mumble/handwavium/nanotechnology). The problem of dust has to be dealt with. Outside of clean rooms, there is always a fairly remarkable amount of dust floating around, much of it silicon dioxide.\* This will get trapped on the surface and become visible, degrading the apparent blackness. Apparently, the cube needs active nanotechnology to either swallow dust particles or repel them. Each has its problems. If the cube swallows the particles, what does it do with them? Discretely spit out the day's accumulation when it thinks no one is looking? And if it repels them, how? A sort of cheat might be to claim that only the sides remain dust-free, which would take much less energy/handwaving, while dust which accumulates on the flat top is simply not visible from the ground. If the entire cube is to remain black, the cube must either ingest dust or transport it to the edges and dump it over the side. This will require some very entertaining nanotech. * All gems will accumumulate dust during wear, and other than corundum-based (sapphire, ruby), topaz or diamond, with emerald a borderline case, any contact will cause microscopic scratches of the gem's surface, dulling it. Even the hard gems require occasional repolishing if they are worn often. If the cube lands near Mecca and is slightly cool to the touch AT ALL TIMES, you have a problem. Summer near Mecca is hardly temperate, and the cube is presumably found outdoors, exposed to the sun. To feel cool, regardless of physical temperature, the cube (at least the surface) must have high thermal conductivity. A very high thermal capacity would help, too. This will mitigate the temperature rise during the day and facilitate energy release at night. So it's possible that the "slightly cool" label was applied when the cube was discovered, and was due to the contrast between the constant temperature and the hot surroundings, but it feels warm at night when it is warmer than the surroundings. [Answer] Addressing the issue of the cubes purpose, it is a teaching aid. It demonstrates some aspect of the universe which we could not learn about from the natural contents and events within our view. The alien race which has been covertly guiding our species' education, has decided that our next assignment is to figure out this cube. It is a big step for them, since they have had to reveal their presence to some extent. From this point forward, we will know that they are out there guiding us; helping us to unravel the secrets of the universe. As for what the cube is, and what it is made of, that will depend on the discovery you want it to reveal. For example, the cube might not be absorbing the light. Instead it might be converting the light into gravity, which is why it is difficult to move. Then your protagonist scientist tries to move it at night and finds that it is much easier. Further experiments might find the cube sinking into the ground when high powered spot lights are pointed its way. The big reveal would involve the firing of a laser at it, which is how we discover that it is not just turning light into mass. The laser escalates the cube's gravity well so much that loose items and people are pulled into it, slamming into the cube's wall. Once the laser stops, the gravity may decrease with time or not. It is up to you. [Answer] It is obviously a device from the future that turns out to be a nexus location to multiple times. Stepping into it (when the door is finally found) transports a person to another time, but only for a limited amount of time. If they leave the device in the alternate time they must return to it before the deadline or be stranded because the device causes a molecular change that must be maintained for the person or items from one time period to travel back to their own time. Remaining too long in an alternate time makes traveling back to your original time fatal since the aforementioned change is one-way. Altering something a second time destroys it through quark decay. So you can travel through time for quick visits as long as you return home between trips. Moving from one alternate time to another alternate time makes going home to your own time impossible immediately. No delay required. The closest you could get to your own time after that is within about 50 years before or after. Bummer. Seems obvious now that you know, right? ]
[Question] [ I am working on a fantasy world with a rich history, but most of it is forgotten by the races that inhabit the planet. This happened because of some kind of magical shockwave that wiped out most humanoids on the planet. What kind of magical effect could it be that specifically targets humanoids? What are the 'rules'? * The magic originated from a single point and as a shockwave spread across the planet and the few survivors live mostly on the other side of the planet. * The magic only affects humanoids, all other animals and plants are unaffected. * The event is triggered by a demon, but after the event a magician that tried to stop the event gets the blame. * When you hear what the magic does it should be clear why it only affected humanoids. Clarification of the question, because it is unclear what I am asking: As stated before, I want the spell to target all humanoid species. So what could the spell target that really sets humanoids apart from other lifeforms? Speach/song has been suggested a few times, but animals can also speak. We humans can't understand what a dog barks or a bird sings, but it is their way to communicate. So it has to be something that only humanoids have. I have been searching for differences in the brain between humans and animals, but I couldn't find much information on that subject. [Answer] I would say, humanoids have souls and that is what is targeted. Being a Demon started the spell it makes even more sense. The spell could be feeding him the energy of the souls (or that is what it was SUPPOSED to do) and so all beings with souls (at least not super strong ones) are destroyed. [Answer] Have you ever heard of a thought paradox? Basically they are infinite loops of reasoning (much like the concept overload) but they only work on pure logic machines. One famous example (as in Portal 2 famous) is: This statement is false. AS previously stated, this type of trap doesn't work on humans as they lack "perfect" logic. But a similar type of mind trap (probably telepathic in nature) could easily fry someone's brains. Alternately, have a DNA-sequence dependent spell that... kills things, in any manner you want, if you have a demon powerful enough to make a world-wide magic doodah, this shouldn't be that much harder. [Answer] A song that acts like a disease, with three parameters: 1. Anyone who hears the song must start singing it too. 2. As you sing it, you sing your years away, aging to dust (or drives you mad, etc) 3. You must be able to understand and fully voice the song for it to have an effect. [Answer] Make it a "concept overload meme". The magic will make humans or sapient creatures that have the capacity to do so think of a concept that creates a recursive infinite loop, thereby consuming all of their brain time to the point that the body shuts down - essentially an infinite loop meme. Obviously we can't know of the concept or we'll die ;) [Answer] The magician is searching for the fabled ether flow origin that powers the lay lines all magicians draw their power from. After finding an ancient tower he breaks a magical barrier holding an imprisoned demon. As they race to the location of the ether origin they find their powers increasing. As they reach the source, the demon cast a spell to enslave all of mankind while the magician cast a spell to destroy the demon, the power streams from the ether going to each cross and results in a near world wide eradication of all humans. Egon Spengler: There's something very important I forgot to tell you. Peter Venkman: What? Spengler: Don't cross the streams. Venkman: Why? Spengler: It would be bad. Venkman: I'm fuzzy on the whole good/bad thing. What do you mean, "bad"?Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light. Ray Stantz: Total protonic reversal! Venkman: Right. That's bad. Okay. All right. Important safety tip. Thanks, Egon. Now if you could just fit in the marshmallow dude. [Answer] Disease. Plenty of necromantic style diseases in fantasy genres. Some diseases only affect people, and do nothing with most other animals. Hardly a problem for plants. Demons are supposed to be nasty anyway. Cover the world in a plague. Might take more than just a instant for everyone to die... but it's much more cruel for whatever survived to witness. [Answer] Babelwave -- the Tower of Babel revisited. One of the unique features of humans is the ability for speech. Something that randomly changed humans to one of a thousand different languages should do the trick. The survivors could eventually rebuild civilization. In an advanced and highly interdependent civilization the sudden removal of the ability to communicate would result in a collapse of society ultimately killing a large percentage of the population. Perhaps the ability to renew large-scale engineering spells would cause failures of magical dams, transportation systems, irrigation systems, medical care, floating cities, etc. to contribute to the fall. If magic was a dominating cheap resource it could unravel civilization to a very devastating degree. Even education could be largely magic-based -- Want to learn something? Easiest way is to drink the corresponding learning potion. Perhaps the Babelwave also causes the magic-users lose the ability 99.9% of the time due to the loss the use of the language of magic. And the Babelwave could have included a component that causes existing magics to decay more rapidly than normal until the Babelwave was cancelled out. The magician that "tried to stop the demon" could have actively been using a universal communication spell at the time of Babelwave. Maybe there could be a few others with the same spell in effect -- presumably this spell would be rare, perhaps very complicated to perform. Defeating the demon would not necessarily restore the prior language abilities already affected. But victory over the demon could have stopped the progression of Babelwave shortly before it completely encircled the planet. In the resulting confusion, it would be very easy for the hero to be stuck with the blame. [Answer] "Poison Fingers" Literally, this silly phrasing; the wave expands and as it passes through objects that classify as fingers, it transforms a small amount of blood in them into toxin. It might exploit demonic name magic, where name of an object gives you a measure of power over that object. People, who lost all fingers or both hands would survive. Plus total crazies who renamed their fingers. [Answer] The spell should poison human food as bread or baked rice. Also, it could affect to drinks like wine or beer. Animals will not be affected as they do not eat this kind of food (maybe some unfortunate dogs). ]
[Question] [ This question is closely related to, but more specific, than the question/comment that inspired it: [Could a modern times time traveler produce an antibiotic in medieval times?](https://worldbuilding.stackexchange.com/questions/13394/could-a-modern-times-time-traveler-produce-an-antibiotic-in-medieval-times/13397?noredirect=1#comment32289_13397). Imagine a person is sent back in time to roughly middle-ages or slightly after, without warning to prepare for it. He has a high school and college education, but not in biology. Perhaps he a mild interest in science/biology; but ultimately is mostly limited to what is taught, and he retained, from college level intro to biology class. He wants to create penicillin, for obvious reasons. He knows the general story of how it was discovered, specifically by accident on a loaf of bread and it was noticed that the mold killed bacteria near it (or at least that's how he remembers the story, it doesn't mater how accurate that memory is since that is what he is working off of when making plans). He has decided to use the below approach to try to discover and recreate it. Assume he has the funding of a king that he impressed with modern technology, his budget is not limitless since the king isn't convinced that he can recreate anything, but it's sufficiently high for him to work with assistance and all reasonable expense covered. To try to create penicillin he first gets many types of bread, and other wheat and food products, and intentionally lets them get moldy. He uses multiple different locations to grow the mold, mostly in dungeons but some in other places that aren't dank and moldy just in case penicillin grows better in other locations. He also gets the local blacksmith to construct very basic petri dishes and starts to grow many different bacterial cultures for testing. Once bacteria and fungus samples exist he will place part of his bacteria samples in a separate dish with some fungus. He will watch to see if the bacteria appears to die out. He doesn't yet have a proper microscope since he hasn't figured out what to ask for to build one yet ([When could a microscope first be made?](https://worldbuilding.stackexchange.com/questions/12116/when-could-a-microscope-first-be-made)). However, if he cultured bacteria well there will be enough built up in his petri dish to be able to see their presence with the naked eye, and thus tell when they appear to be killed. He also gets a number of poor saps to play guanine pig if needed. Perhaps he gets partial pardons for criminals that would have be hung otherwise if they agree to play test dummy. He isn't unethical enough to do anything he considers to have a high chance of killing anyone, but is willing to use them as test subjects for what he considers lower risk human trials, especially considering how much good the drug will do if successful. If he gets a fungus that appears to be antibacterial he will have some of this test subjects try it to see rather it makes them ill. He tries both oral consumption and exposing it to an open wound. He would start in very tiny quantities and only work his way up to higher levels if his subjects appear unharmed, generally he is trying to treat the subjects well and make their working for him be a clear and significant benefit over the alternative. He will use separate controls later to test larger quantities of the fungus to ensure his original subjects didn't build up unnaturally high immunities to it from constant exposure to lower quantities. He is also aware that test subjects may develop germs with immunity to his fungus and so will use different subjects for testing the effectiveness of his fungus in fighting disease. Assuming positive results he moves on to larger controlled trials with peasants, in the same way that we would do control trials with a new antibiotic today, other then the lack of infrastructure and communication systems making it harder to do quite as large a scale as he would prefer. He generally takes his times, uses controls (as much as he can given the small number of samples/subjects he is working with), and triple checks any apparent result before moving on. However, while he has a decent understanding of the scientific method and intelligent he is not a scientist, and may still forget to control for certain variables or otherwise make mistakes that come from doing a job he was never taught how to do properly. My main question is, would this work? What are the odds of his discovering *any* antibiotic fungus, that is relatively safe for humans, using this approach? He doesn't know what he needs to do to recreate penicillin, and I doubt he would find the actual penicillin fungus, but surely there are other antibiotic fungus he could discover which would suffice? Assuming the main question is answered, and that this approach can work, here are some follow up questions that would be nice to have feedback on. The remaining are not mandatory to answer this question, I can post separate questions for them if need be, but any feedback that one wishes to add addressing them is welcomed. 1. what are the odds of negative results of this experiment, and what sort of result could happen? How badly will his test subjects suffer from eating their moldy bread? 2. Even if he finds a good fungus how easy would it be to then culture, grow, deliver, and teach others how to use it such that it would prove effective in fighting infection? Would it have to be reserved for rich high-paying nobles because they can't culture enough for regular use? He will try to prevent overuse creating penicillin immune bacteria, but the implications of such immunities are off-topic enough to likely warrant their own question later. 3. how long would it be expected for this to take? Obviously this is more then a month's effort, but are we talking a year, a decade, or a lifetime? [Answer] TL:DR: This is going to be very difficult, if not effectively impossible. At any rate, if the individual in question does not have at least a solid grounding in biology, and preferably at least a year of modern university-level microbiology, they are most likely to spend a lifetime re-creating the tools needed to even *begin* to search effectively for *any* effective antibiotic, let alone penicillin. Here are the problems: **Growth Media** Bacterial cultures don't generally grow on just anything. To get most strains or species to grow, you need a growth medium with basic nutrients added. I did Microbiology 101, which was enough to tell me *what* [nutrient agar](https://en.wikipedia.org/wiki/Nutrient_agar) is, and how to prepare it (follow the instructions on the tin), but at that level it was only glossed over how to actually make it from scratch. Then, there are other types of [agar](https://en.wikipedia.org/wiki/Agar), each designed to sustain fastidious bacteria with particular requirements or to assist in identification. You may well not even be able to *grow* some types of infectious bacteria without specific [types of agar](https://en.wikipedia.org/wiki/Agar_plate), let alone test them for antibiotic resistance. Then you have the problem of the moulds you are testing. They, too, will require suitable growth media, and for the most part nutrient agar will be suitable, though some valuable strains may be more fastidious, and may require special media. **Equipment and Techniques** The equipment used in microbiology labs is fairly basic for *our* society, but is not *nearly* so basic for a medieval society. Pretty much *everything* in a lab takes place around a [Bunsen](https://en.wikipedia.org/wiki/Bunsen_burner), [Teclu](https://en.wikipedia.org/wiki/Teclu_burner) or [Meker](https://en.wikipedia.org/wiki/Meker-Fisher_burner) burner, which is commonly used to sterilise things such as [inoculation loops](https://en.wikipedia.org/wiki/Inoculation_loop), which have wide application. Inoculation loops require wire that will not corrode, even at high temperatures. These burners wouldn't even have *fuel* readily available in the medieval period, and even a wealthy noble might baulk at being told that (very pricey) fine platinum wire is required. It takes a whole semester at Uni to train a student how to perform the gamut of basic microbiological techniques such as [streaking](https://en.wikipedia.org/wiki/Streaking_(microbiology)) (to isolate genetically pure strains of bacteria) without making mistakes that result in contamination. As one example, to streak an agar plate to isolate individual bacterial species from a basic liquid culture of mixed bacterial species, the microbiologist must: 1. Set up their burner so that it is between themselves and their equipment so that the flame sterilises their exhaled air - otherwise the plates are likely to be contaminated by the microbiologist's breath-borne bacteria. 2. Set the burner to produce a hot blue flame. Yellow flames deposit soot on the inoculation loop, which contaminates the plates, and is not considered hot enough to kill some heat-resistant bacteria. 3. Sterilise the inoculation loop by putting it just outside the blue part of the burner flame. It is a common beginner's mistake to put the loop inside the blue cone of a Bunsen flame, which is quite cold. The wire loop must be heated cherry red ("They're not dead until it's red!") or better still, orange, to kill any contaminating bacteria. Cool the loop by quenching it in an uninoculated portion of the plate. Failure to do this results in the heat killing the bacteria that it is intended to move. 4. Dip the inoculation loop in the liquid culture and rub it across about a third of an agar plate. 5. Sterilise and quench the loop. Failing to do this results in an undifferentiated bacterial lawn. 6. Streak several times from the initial inoculation to an uninoculated part of the plate. 7. Sterilise and quench the loop again. 8. Streak from the secondary inoculation toward an uninoculated area of the plate, being careful not to contact the primary inoculation, or the culture will not be properly diluted. 9. Repeat 6-8 a couple more times, ending in a squiggle in the centre of the plate. The result of this is that bacteria are eventually deposited individually across the plate with sufficient separation that after they are incubated, the colonies are separate, and can be considered to be a single species. Then, we have the techniques needed to isolate potential antibiotics. Once isolated, the potential antibiotics are impregnated into standard-sized absorbent disks *in known concentrations* and placed on a [lawn](https://en.wikipedia.org/wiki/Bacterial_lawn) of the target bacterium. When cultured, the efficacy of the antibiotic can be shown by the size of the clear area around the disk that carries it. Without knowing concentrations, you may reject a better antibiotic just because you didn't collect as much of it. How long would it take our microbiologically ignorant time traveller to re-create even these *basic* techniques? **Isolation** Isolating a fungus that produces an effective *and safe* [antibiotic](https://en.wikipedia.org/wiki/Antibiotics) is the next problem. Fleming discovered Penicillin effectively by accident, and it took around ten years before he and his successors Florey and Chain [succeeded in isolating](http://www.abc.net.au/science/slab/florey/story.htm) a strain of penicillium mould that produced penicillin in sufficient quantities to be commercially viable. "Mouldy" Mary Hunt, Florey's assistant, spent much of her time scouring local markets for mouldy produce in the hopes of finding an active penicillin-producing fungus. Our time traveller should be grateful to find *any* antibiotic-producing fungus, let alone an active *penicillin*-producing strain. A great many fungi *do* produce bactericidal compounds, but these compounds are either themselves - or are accompanied by - compounds toxic to humans. There is little point administering an antibiotic which will also sicken or kill the patient. The challenge is in finding one with sufficient specificity that produces its active compound in sufficient quantity. **Specificity** Antibiotics tend to be specific to certain bacteria. [Penicillin](https://en.wikipedia.org/wiki/Benzylpenicillin) is specific to mostly [Gram-Positive bacteria](https://en.wikipedia.org/wiki/Gram-positive_bacteria), and treating a patient with a [Gram-Negative](https://en.wikipedia.org/wiki/Gram-negative_bacteria) bacterial infection *may* be completely ineffective. Whatever antibiotic our time-traveller is lucky enough to discover could well be similarly specific. **Production** Once a suitable strain is found, it must be [produced](https://en.wikipedia.org/wiki/Production_of_antibiotics) in sufficient quantity. [Industrial fermentation](https://en.wikipedia.org/wiki/Industrial_fermentation) tanks have their own special engineering and microbiological challenges, such as cleanliness, temperature regulation (Cooling can be as important as heating), nutrient supply, oxygen supply, foaming control, agitation and harvesting. Operation of industrial fermentation equipment is a part of the coursework for later years of study in Microbiology that I never undertook - so obviously not a trivial subject. **Potential results of proposed approach** If our ignorant time traveller feeds already ill patients with various moulds or fungi in the hopes of chancing upon one that produces an antibiotic, then he is doomed to frustration and failure. The odds are that few fungi produce suitable antibiotics, and none are likely to produce *sufficient* antibiotics to have any effect. Most likely, his patients will die or recover on the strengths of their own immune systems, and their tolerance to both the initial bacterial infection *and* the fungal infection that our well-meaning but ignorant time traveller subjects them to. Finding a patron rich enough to fund all these experiments - whether conducted properly as I have detailed, or otherwise as the OP detailed - would be quite difficult. The most likely patron would be royalty or nobility. Then, the second difficulty that our aspiring microbiologist would face would to remain unexecuted and unimprisoned in the face of an impatient nobleman without the least idea of what he signed up for demanding results *now, or else!* when the experiments drag on apparently interminably without the least signs of results other than piles of glassware and other strange apparatus, and ongoing bills for various strange and difficult-to-procure compounds. Even a noble patron with the patience of a saint could make all sorts of inappropriate suggestions for speeding matters and for cost-cutting, and may intercept and alter purchase orders, in a well-meaning way, of course. ("Why does he need *agar*? Let's substitute gelatine, it's cheaper!") Our time traveller would have to educate his patron (or a *trusted* advisor) nearly as well as he was himself in order to be fully understood and properly supported. If our time-traveller succeeded at all, he'd likely be an old man by the time he did so. [Answer] There are a number of faults with your premise: ## Availability of Penicillin Penicillium is actually a very common genus of fungi, and grows all over the place. Flemming's accidental discovery of penicillin wouldn't have happened otherwise. However, penicillium won't just produce penicillin for the fun of it. It only produces penicillin when under stress (under attack by bacteria). Simply growing the fungus on bread won't necessarily get you penicillin. ## Bacteria and Petri dishes Petri dishes aren't anything special. You could use bowls, plates, etc for the same effect. The key ingredient here is agar, which is the growth medium used to create large macroscopic bacteria colonies. Spitting into a metal bowl won't get you what you want. And that's going to be the biggest problem: growing colonies of bacteria, that are just bacteria. Unless our time traveler can create a sterile, viable growth medium, then he's going to have a tremendously difficult time isolating bacteria from fungi (which will likely be some kind of antibiotic producing fungi at that). ## Audience Our time traveler is likely going back in time at least a few centuries before the age of reason. People have no understanding of germ theory, the scientific method, or modern medicine. He might be able to get a few monks on his side, but he'll have a difficult time convincing a king that: 1. He's not a raving lunatic. 2. He needs to go through so much ridiculous bureaucratic nonsense to make a cure. 3. He's worth the funding. --- At the end of the day, we have to ask the correct question: Is the knowledge that the blue-green fungus that grows on fruits and bread produces a antibiotic compound enough to produce an effective antibiotic? I believe that the answer is, **yes**. However, it won't be through a complicated trial-and-error, double-blind experiment type of method. It will simply be by feeding people mold. Eating penicillin is an effective way to get the antibiotic into the body. Also, you can just slap some mold on cuts or gashes, and that will help keep the wounds free from infection. The most valuable skill, at the end of the day, is being able to *identify* penicillin in the wild. There are some other bad molds and fungi out there, so simply knowing that penicillin is a mold isn't as useful as it could be otherwise. [Answer] This approach seems sound, and may be the proper approach given what the time traveler knows and the tools available. (It also appears to be a similar approach to the one taken in [this paper](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC123731/)) After all, penicillin was discovered [by some contamination](http://en.wikipedia.org/wiki/Penicillin#Discovery). There are some issues: 1. Penicillin has been [found to grow best](http://www.pbs.org/wgbh/aso/databank/entries/dm28pe.html) on corn, which is a new world crop, and cantaloupe, which does not natively grow in Europe. Finding a suitable substrate for growing will be just as hard as getting the correct mold. (That being said, [cheese](http://en.wikipedia.org/wiki/Blue_cheese) and [sausages](http://en.wikipedia.org/wiki/List_of_microorganisms_used_in_food_and_beverage_preparation) may be the time traveller's best bet.) 2. Penicillium Molds can produce [mycotoxins](http://www.moldbacteria.com/mold/penicillium.html), toxins from fungi, which can be deadly to humans. Only certain species can produce penicillin; others may kill off bacteria with their mycotoxins. The time traveller will need to be very careful in selecting the moulds. I would say that the time traveller would expect to see more negative results than positives. The time traveller is looking for a particular kind of mold, and even molds within the same family may not have the desired effect. Although penicillium molds are everywhere, the correct ones may not be captured. This effort could take his lifetime, but likely on the order of years. Finding a suitable substrate to grow the mold on for mass production may never happen, because of #1 above. I see it being an uncommon, but potent, cure. Therefore richer families (or those whom the time traveller takes pity on) would profit from this. ]
[Question] [ **Ancient divers:** Vitruvius connected a long tube of cloth, impregnated with special waxes, with bronze rings every 10 cm to hold the tube open, to a pair of bellows connected to crude cheek valves. This long tube was connected to a mask made of bronze containning a pair of glasses and a checkvalve that allowed air to escape but no water to enter the mask. The diving aparattus was born. ![airtube](https://i.stack.imgur.com/y35aX.png) ![mask](https://i.stack.imgur.com/ovAi8.png) 1 - Bronze mask. 2 - Glass vision ports. 3 - Tube connection. 4 - Cheek valve. **Question:** What would be the consequences of this on naval warfare? How this could be explored economically? Are there resources underwater that could be taken via divers? [Answer] Be careful with the actual apparatus...you need to ensure that it remains pressurized as well. If the device works: I cannot see that big of an advantage directly to the military...it's applications for attacking / sabotage seems pretty minimal...if the Romans had explosives that could be transported underwater maybe? But thats not the major benefit I would see. Your major use here is salvation...the countless number of ships that sank during wars (and peace time for that matter) from military ships to merchants and everything in between are sitting on the bottom of the Mediterranean. Much of the Mediterranean is quite shallow (100 meters?) and this device would allow for large scale salvation operations...sunken treasure much? When Carthage was burned, a fantastic amount of treasure was sunk to the bottom of their harbor...all of which could be recovered by your ancient divers. [Answer] Well, if you're being literal in your description, the first consequence would be a bunch of dead divers. The problem is in the valve - if it can't 100% reliably withstand the pressure of 5 atmospheres or thereabouts, a failure will lead to *excarnation* - the diver being squashed into his helmet by water pressure. You can still get some limited utility, if you don't go *too* deep, though; having even shallow-water divers (even with diving bells or similar apparata) will help a lot with salvaging ships (and their cargo) if they sank in or near a harbour. As for warfare, it doesn't help much; you need the pump to stay with (above) the diver at all times, and the diver will be a lot slower than a galley. [Answer] Romans did not know to make clear glass, or rubber seals, so your divers would dead. Plus metal was not cheap, even nails considered high technology... No effect on ship figths, I think. Ship fights happen far out at sea, where divers useless anyway. [Answer] **If you do not have a compressed air supply:** The suggested drawback of divers hemorrhaging out through mouth and nose because of pressure differential is admittedly colorful and dramatic, but *absolutely will not happen* if you're not giving the divers compressed air. Reason: **diaphragm and intracostal muscles are not strong enough to inflate the lungs** against a pressure differential, so **your divers will not descend** while breathing unless they have compressed air. I know this from personal experience: in my teenaged ignorance I tried to see how deep I could go with an adequately rigid tube. It turned out to be a pretty trivial depth, a few feet IIRC. **If you do provide compressed air:** It's still going to be highly questionable. The likeliest injury would be [air embolism](http://en.wikipedia.org/wiki/Air_embolism), which is often fatal (and frequently causes brain damage when the victim survives.) This happens when ascending with compressed air in the lungs and (naturally enough, if you haven't been trained otherwise) holding your breath all the way to the surface. As the air in your lungs expands, it tends to rupture the alveoli and force its way into the bloodstream. Neurological symptoms (up to and including death) are caused by bubbles blocking blood flow to the brain. The biggest gotcha about air embolism: **the maximum expansion happens closest to the surface.** In other words, the danger increases as you almost get to to breathable air. :-( Since the only treatment for this is a hyperbaric chamber, your divers in Roman times would be unlikely to receive treatment. Yes, hyperbaric chambers might well be invented - eventually - to treat the commoner malady of [the bends](http://en.wikipedia.org/wiki/Decompression_sickness), but it's kind of hard to see the engineering thought progressing like that. Romans were good engineers, no question; but they were not much for theoretical physics. And, since this issue is explained by [Boyle's Law](http://en.wikipedia.org/wiki/Boyle%27s_law), which didn't emerge in our world until the 17th Century CE, you would really need to hack your timeline of scientific discovery... ]
[Question] [ Could life be sustained only by a gas? Humans need food, water and air but can a ET or Alien could just live off gas. [Answer] If it were possible, I would think they would be very slow growing, and likely have mouths like a [Baleen Whale](http://en.wikipedia.org/wiki/Baleen_whale) or the [Whale Shark](http://en.wikipedia.org/wiki/Whale_shark). It would 'filter' large amounts of gas for the elements and dust it needs to survive. This is assuming that the organism lives in the 'air' at least primarily so that is why it has adapted to this way of living. I would guess that if one life form made it there would be a pyramid of organisms and of course the larger would feed off the smaller to help concentrate raw materials. So I guess this isn't really living off 'gas'. It would take a lot of chemical acrobatics to only live off of stuff in a gaseous state, just collecting building materials would be hard. Of course if it is a highly volcanic planet that spews lots of chemicals into the atmosphere might make it a little easier, but once again, it would not likely be surviving on 'gas' alone. [Answer] This scenario is highly problematic for organic life forms. Recall that elements come in three different forms : solid, liquid, and gas. Converting solids to liquids requires heat (thermal energy). Similarly converting liquids to gas requires heat. The hotter the environment, the greater the number of elements that are available as gas. An organic life form which included water in its body could not exist in an environment with a temperature above boiling point. Take iron, which is essential for human life (and presumably most organic life on earth). Iron has a boiling point of 2862 °C. By comparison, the surface of the planet Mercury is about 470 °C at its maximum. So any life form capable of sustaining life by consuming only gas would need to be based on a very narrow range of chemical elements. This seriously limits the scope for complexity. A half-way approach may be this : A very turbulent environment could result in particles of all solid form nutrients to be circulated in the air. But this is kind of bending the rules a bit. I think your only option would be a non-organic life form - say a computer based life form. All a computer needs to run is energy, and this could be obtained by burning gases (e.g., hydrogen) in the environment. [Answer] Assuming it can get traces of minerals from dust, yes. Consider plants: The primary reaction sequence is combining water and carbon dioxide to make plant material. They normally use liquid water going from the roots to the leaves as a transport medium but a pure gas environment sounds like a zero-g environment, transport will be much easier. [Answer] Possibly not on our Earth, for reasons others have mentioned. But if you'll accept any kind of gas, you could have an organism with a biology very much like ours. Just offhand, I can think of two substances that humans can metabolize for energy that are already close to being gases under normal conditions: ethanol and acetone. Make the temperature a little higher, or the air pressure a little lower, and those would predominantly be gas. You could have a respiratory system that uses active transport to efficiently extract them from the air. How much energy could a vapovore get this way? Humans can exchange about 0.5L of air with a normal breath, which comes to 10,800L per day. If you were breathing pure ethanol at 1 atm and 25C, its density would be 46g/25L (unless my memory of how gases work is way off), so if you could extract 10% of what you inhale, you'd get around 1,987g/day. Humans can get around 7 Calories / g from ethanol, so that's nearly 14,000 Calories per day! Of course, these assumptions are wildly unrealistic, but it shows that even at a much lower efficiency and a lower atmospheric concentration, the idea isn't unthinkable. ]
[Question] [ I put a force field dome over my city. How would that affect the weather inside the city, and outside it? Specification of the city: * 10 × 40 km on the surface * 1 km in height * dome would be 2 to 3 km in height Specification of the area around that City: * tundra-like area * about 50 km to the south lies an ocean * no mountains in sight The context is the same as [How could a force field dome be realized in my city?](https://worldbuilding.stackexchange.com/questions/1043/how-could-a-force-field-dome-be-realized-in-my-city). The Force field blocks any movement through it when it is activated. So everything that is in the dome stays in the dome. [Answer] I will make the assumption that air and water can't get into the dome. And I will also assume that this dome is feasible. The weather from the exterior won't impact the interior except for the temperature. Since you said it is a tundra it is quite cold. According to the Köppen climate classification, the mean monthly temperature never go above 10°C. It's not a problem, there are several cities above 10 000 people with a tundra climate. On the exterior, I doubt the dome would have any significant impact. Expect that the water falling on the dome would accumulate around it at the base. It is important to say that the ground is permafrost and cannot absorb water (or very little). Water will accumulate if there is a natural depression. Water is not always a concern in the tundra because some places receive almost no rain. Even if the force field can be deactivated, the city still need to be self sufficient for a long period of time. There won't be any exchange of water or air with the exterior. They need to have the tools to recycle the air and water (to purify them). Otherwise they will suffocate and the water will become corrupted. \*About the weather inside the dome, I think you could have some condensation but I'm not sure since there is no difference in temperature between the exterior and interior. I'll let someone else answer on that topic. [Answer] First of all lets see the shape of the dome: ![dome shape](https://i.stack.imgur.com/JDFJ5.png) *That's 40km in radius ( (2+2)\*10 = 40km ) and 3km in height ( 0.3\*10 = 3km )* [link](http://fooplot.com/plot/cyzn9uu6t4) *many thanks to Liath for revealing this online gem* That's pretty flat. I used Kelly Thomas's approach and compared it to a geological feature, but a hill instead of a mountain since this is a *lot* less steep. However, it turns out the tallest hills are about 1km tall and *still* cause [rain shadows](http://en.wikipedia.org/wiki/Rain_shadow) despite the flatness. Here's some examples: * The [Judaean Mountains](http://en.wikipedia.org/wiki/Judaean_Mountains) which are 1km tall and relatively flat compared to what we think of as mountains, but cause enough of a difference to shadow the Judaean Desert and the Dead Sea. Now *that's* an effect. * The [Tibetan Plateau](http://en.wikipedia.org/wiki/Tibetan_Plateau), which again, while quite tall, is a relatively flat area, not very jagged and steep. At an average elevation of 4.5km, it creates a steppe region and funnels water down into lakes. This gives us a sense of scale - your dome is a huge mountain. I apparently followed Kelly's footsteps again because I also found the Alaskan woody tundra mentioned in the answer and it seems to indeed be caused by rain shadowing. The question is, if it is *already* a tundra and then you add a rain shadow, what happens? Looking around for a mountainless tundra, I found nothing - in fact searching for it just gave me results for mountains related to tundras. However, the *arctic* tundra variant that applies to the poles might be closer. The problem is, the climate there is so cold, it's like what do you expect? They also seem to have an altitude to them (maybe your area is a plateau/plains at high altitude). [This page](http://lib.colostate.edu/wildlife/tundra-biome.html) however implies that the antarctic tundra isn't really a tundra but more like a desert that is too damn cold to not be a tundra-like biome. The problem remains - unless your dome *caused* the tundra in the first place - it would be cold plains or a regular desert (just not sandy). But tundra is believable enough I guess. As Vincent mentions, you need to recycle water and air, but considering how large the dome is and how mountains in tundras tend to be the sources of rivers and lakes, why not just collect the water off the dome and create an artificial river or lake inside the dome? Best park evar. With enough rainfall, you won't need to dig for water, it'll just fall out of the sky. ## Uh oh... Here's the extra issue with the conditions *within* the dome. The outside will probably not be too much affected by your dome, considering it's already practically a desert. However, your dome is large enough to have its own weather :D Take a look at this: * [Er Wang Dong Cave](http://en.wikipedia.org/wiki/Er_Wang_Dong). So massive, it has weather (that was actually the title for *every single article* on this cave). At 42km deep, "dong" indeed. There's pictures here: + <http://www.unbelievable-facts.com/2014/08/18-first-ever-images-of-cave-so-massive.html> There's more of these I assume, but we have important information from this: the enclosed spaces are nowhere near as large as the space your dome encloses. Since its maximum depth is about 450m, we can assume the areas inside are going to be less tall and your dome is 6 times taller (or 4 if it's 2km). Since you're in a tundra it's cold enough to have vapors condense. Also, it's as long as your city but still a cave - so your city will have *more enclosed space* that that entire beast of a cave in total - I'd assume about 10-20 times as much, *all in one area*. The question is, does sunlight change this? I'd assume not since clouds generally don't seem to care about sunlight, nor does the cave, but I'm no meteorologist. It may cause a warmer climate inside though. You could have a greenhouse effect on your hands, but the temperature (I *assume*) shouldn't be too high. A lot of humidity and heat will be trapped due to the people (assuming they're warmblooded) and water, but you need some filtration and conditioning for the air anyway, just in case, so that might be able to regulate things. Considering you'll have *weather* though, it *might* (again, I *assume*) not be as critical since there's plenty of space for circulation. Also, you might want to expect birds :P At 10x40km (400 km^2) and considering [this](http://www.citymayors.com/statistics/largest-cities-area-125.html) and [this](http://en.wikipedia.org/wiki/New_York_metropolitan_area) we can see that the New York metropolitan area covers about 34km^2 and your city is over 10 times as big. That's pretty big and I'd assume that its *microclimate* will be closer to an actual climate, who's nature will depend heavily on what activities take place within. *An interesting aside - the [buckyball guy](http://en.wikipedia.org/wiki/Buckminster_Fuller) had proposed a [dome for New York](http://gothamist.com/2012/03/08/the_1960_plan_to_put_a_dome_over_mi.php) back in the 60s.* [Answer] The inside of the dome would need to take substantial step to avoid the Urban heat island effect. In terrestial cities the chief cause of the heat island effect is the lower albedo due to dark building materials. - This can be avoided by using light building materials instead. However there are two other causes that will need to be handled. First the city you describe is more than 10 times the size of NY - and at 1 km height can be expected to have significantly higher population density. So human activities that generate waste heat will cause warming, this is already noticable in some terrestial cities. Here is an [Irregular Webcomic strip](http://www.irregularwebcomic.net/396.html) describing the impact of this for a planet sized city. Secondly, and directly caused by the field, your city is in effect a greenhouse. Trapping the air heated by the surfaces that are heated by the sun, or by waste heat from human acticity, and preventing convection from carrying that air away. Since convection is an effective way of temperature transfer preventing this will have implications for temperatures inside the dome. I can not estimate how many degrees hotter the inside will be when compared to the outside, but expect the city designers to be very happy about the fact that they are in a naturally cold environment rather than in a hot one. Even with a outside temperature below 0 degrees Centigrade. I expect temperature control inside will stuggle with keeping people cool rather than heating. Edit: I see from your other question that the force field should "block line of sight". This changes things above because it affects what happens with sunlight. If the force field tends to reflect light I have no idea what will happen, the inside would be quite cold if there where no people - but with people it depends on how energy efficient they are. If the force field absorbs light I suspect that the inside of the dome would be too hot to be habitable. [Answer] A dome of 2-3 kilometers height would cause a [rain shadow](http://en.wikipedia.org/wiki/Rain_shadow) on its lee side. [![enter image description here](https://i.stack.imgur.com/JUJ3c.jpg)](http://en.wikipedia.org/wiki/File:Rainshadow_copy.jpg) At this height it is comparable with many of the [worlds mountains](http://en.wikipedia.org/wiki/List_of_mountains_by_elevation) and would push any humid air passing over up to a higher elevation. As pressure decreases the adiabatic dew point rises causing an increase in precipitation over the windward side of the dome, and a decrease in precipitation as dryer air travels downwind. While on Earth rain shadows are more commonly seen at lower latitudes examples can be found in tundra like climates. As an example the [Brooks Range](http://en.wikipedia.org/wiki/Brooks_Range) in Alaska [casts a rain shadow](http://www.weatherwise.org/Archives/Back%20Issues/2009/January-February%202009/full-shulski-mogil.html) over the [woody tundra](http://globalrangelands.org/alaska/wooded-tundra) located downwind. ]
[Question] [ Me and my friend have a passion project where we mainly focus on a habitable planet; Ahmokea. For a little while we wanted to include ammonia in the atmosphere on a large scale so it could be part of the animals & plant's equal exchange (just like how O2 is made into CO2 by us and the CO2 into O2 by plants.) But the thing is, recently I've tried looking deeper into it to see how realistic that would be and ammonia wouldn't really work because ammonia would kill most of it's life (from what I've heard), so I don't really know what could be an alternative to this idea. Is there any atoms or molecules that could be part of the equal exchange on Ahmokea? (Sorry for my terrible English/spelling.) Also, forgot to add: Ahmokea's atmosphere mostly is composed of nitrogen and oxygen just like on Earth. The ammonia would have been a low percentage but significant enough to affect the life forms on the planet. The plants also use a pigment called "retinal" instead of chlorophyll, I don't exactly know if that is significant or not. My friend and I thought of adding nitrifying bacteria in the process of the animals and plants breathing, but we aren't sure if that's realistic enough that it would work in general. [Answer] * Nitrogen causes significant impairment at pressures above about 4 atm, and will cause unconsciousness and death at sufficiently high pressure. * Oxygen causes damage to the central nervous system, lungs, and eyes at more than about a third of an atmosphere. The effects are a function of time and pressure and individual tolerance, but include seizures, tunnel vision, dizziness, confusion, etc. Note that increasing oxygen levels will also increase fire hazards, though. * Our bodies use CO2 buildup to regulate respiration, and too much atmospheric CO2 will disrupt that as well as disturbing blood pH, which many things are sensitive to. * Levels of ammonia that are dangerous to us certainly don't rule out life. You would need a biological source that constantly replenishes it though, and it is energy-intensive to make, which is why few organisms do so. Then there are things like carbon monoxide that is mainly a hazard because we use hemoglobin for oxygen transport, or hydrogen cyanide which interferes with a very specific biochemical pathway in mitochondria, and might just not be an issue for alien life. [Answer] I once toyed around with a speculative biology project where I designed the biochemistry and physiology of a creature I called the "siphon sloth". Most of the details of the animal's physiology aren't relevant here, but the primary impetus for the exercise was to consider how thermoregulation might work on a very hot planet. Organisms on this theoretical nameless planet didn't struggle to keep warm, as we do on earth, but to keep cool. There aren't "warm and cold blooded" animals, but "cool and hot blooded" animals, and the siphon sloth was initially just a thought experiment about how a "cool blooded" animal in such an ecosystem could work. The reason I bring this up is that my cooling mechanism involved hijacking the nitrogenous waste removal system that, in us, produces urine. The ammonia would be extracted from the blood and concentrated but, rather than simply being expelled, would then be pumped into a blood vessel rich, sac-like organ where it could expand, absorbing heat like an old ammonia air conditioner. This expanded ammonia would then be expelled from the body as gaseous waste. On this planet, there would be a good reason for there to be a high concentration of ammonia in the atmosphere, as it is constantly being replenished by the prevalence of "cool blooded" organisms on the planet. Your planet needs some sort of mechanism like this, some reason why the things on this planet are making loads of ammonia. The issue of ammonia being toxic isn't an issue really. If you evolved in it it's not going to be toxic to you. The big issue is how did that ammonia get up there, and the answer is going to be "someone needed to make it to do something that keeps them from dying". Once that happens and atmospheric ammonia is a reality, everything else is going to figure out ways to either tolerate or use it. [Answer] One thing I can think of is a very high concentration of carbon dioxide, mainly at or above the 5,500 PPM value as stated here [1993-1994 ACGIH TLV: 5,000 ppm (9,000 mg/m3) TWA](https://www.cdc.gov/niosh/idlh/124389.html) The idea is there is enough oxygen for life as we know it. However, humans have not evolved to handle this amount of carbon dioxide in the atmosphere. One good way to support the statement that this planet has a higher concentration of CO2 is being further outside the habitable zone we are accustomed to, so if plant life consumes too much of the CO2 the greenhouse effect will be reduced and the planet will be too cold. This planet would be more susceptible to the "[snowball earth](https://en.wikipedia.org/wiki/Snowball_Earth)" effect and therefore would be more dependent on volcanic activity to replenish carbon dioxide. Ammonia would not be sustainable in an earth-like atmosphere because it would oxidize into water and release the nitrogen. So if you are looking for a more exotic atmosphere, you may try chlorine, like in [chlorine planets](https://planetstar.fandom.com/wiki/Chlorine_planet). Now you may say that chlorine would be worse than ammonia. It is true for life on Earth. It may be possible, however, that life on that planet has evolved to live in a chlorine-rich atmosphere. When oxygen-based photosynthesis appeared on the planet, many life forms have suffered from the "[great oxidation event](https://en.wikipedia.org/wiki/Great_Oxidation_Event)". However, many organisms have adapted and evolved to what we see today. ]
[Question] [ So I've been working on a project where I modify the Solar System, and I originally had a small gas planet(like 5-10 earth massses) named Juno orbiting between Jupiter and Saturn. However, as it turns out, the area between Jupiter and Saturn is rather precarious - when I ran the system in a simulation the two gas giants ejected my precious little Juno from the Solar System within 1 million years or so. I don't want all the worldbuilding work I put into Juno to go to waste, however, so I'm thinking that Juno could be a Lagrangian companion to Jupiter, sharing the giant planet's orbit. The idea isn't too ludicrous - a lot of asteroids(the Trojans) do this exact same thing. However, this is not an asteroid - this is a rather massive planet. When I ran it in the simulation it surprisingly seemed to be stable, but I want to ensure that it remains stable over billions of years. So could my gas dwarf share Jupiter's orbit? [Answer] The solar system itself is NOT stable over billion of years, as any good N body system does. And the hypothesis of Theia tells you that a planet in a Lagrangian point is easily perturbed out of it with dramatic consequences. [Answer] Nip Dip says they ran a simulation of the set up and it seemed to be stable - for the time period covered. But they ask about stability over a period of billions of years, indicating their simulation didn't cover that long a period. Astrophysicist Sean Raymond does similar simulations of solar system evolution as part of his job. And he says: > > I am available to help out with ideas for books, movies, games or any other projects set on other planets. My specialties are: > > > World building: creating scientifically accurate settings for storytelling > > > Understanding what it would feel like to live on other (custom-built) worlds. How would the stars move? What would the weather be like? > > > Testing the scientific validity of already-created settings. > > > <https://planetplanet.net/about/> And you should consider: > > As a rule of thumb, the system is likely to be long-lived if m1 > 100m2 > 10,000m3 (in which m1, m2, and m3 are the masses of the star, planet, and trojan). > > > <https://en.wikipedia.org/wiki/Trojan_(celestial_body)#Stability> So according to that rule of thumb, a Jupiter trojan would have long time stable orbit if the trojan had a mass less than 0.0001 that of Jupiter or less than 0.03178 that of Earth. I note that some of the imaginary planetary systems Raymond has designed on his blog seem to feature trojans which break that rule of thumb. Raymond has also done simulations with planets in stable rings or arcs. If anyone knows of exceptions to that rule of thumb and is able to calculate them Raymond would seem to be a good choice to start asking. And if it is impossible for Juno to have a long term enough stable orbit as a Jupiter Trojan, Raymond be able to find a more stable place in the solar system for you to put Juno. You should also consider the scale of science fiction hardness. <https://tvtropes.org/pmwiki/pmwiki.php/SlidingScale/MohsScaleOfScienceFictionHardness> If you are content to have a low score in that scale, like *star Wars*, for example, you can put your fictional planet Juno wherever you want without worrying about how plausible the orbit is. [Answer] > > stable over billions of years > > > Over a handful billion years you will have [planetary migration](https://en.wikipedia.org/wiki/Planetary_migration). According to some current models, gas and ice giants will move a lot. There is even an hypothesis suggesting that [Jupiter and Saturn moved inward, then outward since they formed](https://en.wikipedia.org/wiki/Grand_tack_hypothesis). While L4 and L5 Lagrange points are considered stable, such migration and the the interactions with a protoplanetary disc make your arrangement very improbable. I think a more plausible way to have such an arrangement is if your planet is a recent capture, having come from another system. ]
[Question] [ I am writing a science fiction novel therefore I am using the idea of the Alcubierre drive for warp travel which involves some handwavium but has roots in theoretical physics (which is my goal). While looking at the NASA design for their hypothetical warp ship: [![enter image description here](https://i.stack.imgur.com/ipf7q.png)](https://i.stack.imgur.com/ipf7q.png) I noticed the two rings (which I assumed it would be for compression of space in front and expansion of space in back). This got me wondering about the negative mass requirement. I understand that using negative mass would allow a repulsion, therefore allowing expansion in the back. However why would the ring in front also need negative mass if it compressing space? Would it make theoretical sense to use dark matter instead (I know dark matter is called dark due to us not knowing exactly what it is but we do know that it is a strong attractive force). If not then why do both rings need the negative mass? Thank you for the help and thoughts. [Answer] > > I know dark matter is called dark due to us not knowing exactly what it is but we do know that it is a strong attractive force > > > The problem with dark matter is that it is very much *not* a strong attractive force. It only seems to interact with the rest of the universe via the weak nuclear force (which is very weak, and quite short ranged) and via gravity (which is weak, but long ranged). Because of this, there's no convenient way in which to corral a useful amount of dark matter in a reasonable volume... you can't keep it in a container, because it will pass straight through the walls basically unimpeded, and you can't trap it in an electromagnetic field which only really leaves gravitational attraction. And if you can generate nice strong gravitational fields in a compact volume, then you don't actually need the gravitational mass provided by dark matter in the first place! > > looking at the NASA design for their hypothetical warp ship, I noticed the two rings > > > These sorts of things are always artist's impressions, because no-one has any idea what the nature of a warp field generator would be. Treat them as inspiration, not engineering guidelines. [Answer] ## Saddling over space time **The ring on the back will push, the ring on the front will pull** The Alcubierre drive is based on deformation of space time itself, creating a means of forward propulsion by folding (or warping) space time into a saddle surface around the ship, which looks like this (projected in 3d) [![enter image description here](https://i.stack.imgur.com/jf7g6.png)](https://i.stack.imgur.com/jf7g6.png) Note the ship is not sticked to the surface, as would be the case in classic models. The ship actually travels straight over space time, and the bent surface in front of the ship provides the shortcut over long distances. The amount of FTL depends on the amount of spacetime "bridged" by the ship's forward movement. The steeper the gradients are, the more space time will be shortcut and the faster your ship will travel. **Rings are different polarity** To create a space time valley in front of the ship, there needs to be a "positive mass", but that is not a real, physical mass, or any object mass. The ship's rings contain field generators that generate an artificial gravitational field, which causes the saddle surface in spacetime to exist. The ship "falls" into forward direction. The saddle surface cannot have a single lobe. On the back of the ship, you have a similar generator that has opposite polarity: it will project a negative mass behind the ship, so the gradient (or perceived gravity) is negative. The saddle surface is huge, it can span light years. But that mode of operation is only safe in interstellar space. In the first weeks of travel, the saddle surface will gradually expand, keeping the middle part tilted, in effect accelerating the ship. At some point it will travel FTL over the valley.. when arrived on the other side a new saddle is generated and the procedure is repeated, until the target is reached. **How you hit the breaks or change direction when using an Alcubierre drive** The ship is actually pushed moving *over* spacetime. That push ends when a platform is formed. The platform will look as follows: [![enter image description here](https://i.stack.imgur.com/1CfBk.png)](https://i.stack.imgur.com/1CfBk.png) While the ship is "on" the platform, it will experience 0G and travel with a single speed. It can decelerate, weaken the gradients, or change direction. During travel, the saddle's shape, allows some velocity control, but the ship can't change direction. The two wheels make the ship only travel straight forward, during FTL. **Mind the exhaust: gravitational wave interference** One little note I can leave about this ancient FTL warp technology: there will be side effects from using it. Your ship will affect the space it travels through. While it expands, the saddle surface will invoke gravitational waves, which are not healthy for life, when subjected to them at close range. For that reason, you can't switch an Alcubierre drive on, anywhere near inhabited planets. A distance of about 80 AU is advised, which is about 2x Pluto's orbit. ]
[Question] [ This here is a plain, simple, good old-fashioned map of our planet: [![enter image description here](https://i.stack.imgur.com/vvHJO.png)](https://i.stack.imgur.com/vvHJO.png) As everyone here would know, land makes up only 29% of the planet's surface. But suppose for a moment that someone has pulled the plug off the ocean to drain enough of the ocean's waters to raise the percentage of land to exactly 50%, not a fraction more. Using our current knowledge of ocean bathymetry, what would a map of such an Earth look like? ***Quick disclaimer--I'm not asking for how this change would affect the atmosphere, the ocean currents, the geography, the climate--that's all for later. Simply what the plain, basic, good old-fashioned map would look like. That's it.*** [Answer] The continental shelves appear quite quickly. I can't give you an exact match to your figure, but my rheumy, ancient eyes suggest that this is about right: A drop of (approx.) 3,500 metres gives us this: [![Map supplied by NASA](https://i.stack.imgur.com/n1Wk4.png)](https://i.stack.imgur.com/n1Wk4.png) Or perhaps a touch more land, a 3,700 metre drop: [![Second map, slightly more land.](https://i.stack.imgur.com/gl6Ma.png)](https://i.stack.imgur.com/gl6Ma.png) NASA's [nifty online tool](https://svs.gsfc.nasa.gov/3487) lets you view the entire process by sea-level drop against the changing map (the runtime-bar slightly obscures the key). Unfortunately there's no percentage, but if anyone cares to write a short bit of code to count the relative proportion of dark pixels, then please chime-in with an edit. [Answer] As comments to the other answer point, closed basins will remain over the overall ocean level, although in the long term it's hard to predict its level - some of them will keep full and spilling out to the ocean becoming lakes, and others will lose more water to evaporation than gain from runoff and will become inland seas with endorheic basins. However, Randal Munroe tried to predict what would happen [if the oceans were drained](https://what-if.xkcd.com/53/) with a drain on the Marianas Trench. The maps for 3 km and 5 km water level drop may give an insight of what the OP is looking for. [![enter image description here](https://i.stack.imgur.com/oCOVw.png)](https://i.stack.imgur.com/oCOVw.png) [![enter image description here](https://i.stack.imgur.com/inQaM.png)](https://i.stack.imgur.com/inQaM.png) ]
[Question] [ The vampire loves fresh blood and often sneaks into houses at night to feast. It would wait for nightfall when the occupants were asleep and then force their fangs into the neck of it's victims. However there is a mystery that puzzles the authorities who are tracking down these highly dangerous criminals: it seems surprising that no blood was spilled on the ground. In fact. there's only 2 clean holes each measuring 10 millimeters in diameter on the victim's body. According to the survivors, the attack happened in their sleep and they only found out later about the punctured holes on their neck as well as finding 2 pieces of serrated blood stained fang on the bed where they slept. How does the design of the serrated fangs benefit the thirsty vampire and why are there no blood stains anywhere? [Answer] # Serration to internally slash blood vessels, reversible anticoagulants to let blood flow, then powerful clotting agents injected into the wounds: That pretty much sums it up. You want to drive straws into the victim, allowing blood to be drawn directly from veins or arteries. Serration allows some tissue destruction as the vampire is drinking blood to open up bleeding while feeding. A mild paralytic and memory blocker (like the [date rape](https://www.webmd.com/mental-health/addiction/date-rape-drugs) drug Rohypnol) facilitate keeping the victim still and causing memory loss to prevent recollection of events. This can be injected with an anticoagulant to ease blood flow. Once you have your fill, then either the fangs inject a clotting agent (like [fibrinogen](https://en.wikipedia.org/wiki/Fibrinogen)) or the fangs actually contain/are made of a clotting agent. fangs made of clotting agent would also prevent any leakage of blood around the insertion site and lead to a very clean area. An outer coating of other material in the areas near the actual bleeding can slowly dissolve, exposing the clotting agent only after the vamp has had a chance to feed. If the fangs are disposable, (i.e. the vampire keeps growing new ones like hair or finger nails), then they simply snap off in the wound to assure the wound clots. Once the wound is full closed, the vamp can pull out the fangs or leave them in, and there would be virtually no bleeding. The whole thing is actually very close to what goes on with a [mosquito bite](https://animals.howstuffworks.com/insects/mosquito.htm). The same needles draw out blood through one tube and inject anticoagulants (or whatever is needed) through another. [Advanced needles](https://www.newscientist.com/article/dn2121-painless-needle-copies-mosquitos-stinger/#:%7E:text=Contrary%20to%20popular%20belief%2C%20a,without%20you%20feeling%20a%20thing.&text=Unlike%20the%20smooth%20surface%20of,only%20small%20points%20in%20contact.) are actually being engineered that use some of the design features used by mosquitos. [![proboscis](https://i.stack.imgur.com/dLkZh.png)](https://i.stack.imgur.com/dLkZh.png) This could be done by a vampire, OR it could be an elaborate scheme dreamed up by some weird fetish people with medical knowledge and determination. [Answer] The vampire doesn't leave a mess behind simply because the "two fangs" left behind are just an elaborate renditions of needles for blood picking. The vampire wants to be safe while eating its meal, and therefore prefers to consume it in a more protected environment than the room of its victim. Being considerate, the vampire uses disposable, single-use needles for picking the blood, and has them shaped like fangs because, you know, a taste for macabre. In this way it has also better chances of properly handling the preparation and after-care of the victim. [Answer] "Vampires" are just a human mutation - they start out as babies, grow up but never (or just very slowly) grow old. Instead of 2 stages of teeth-growth (child + grown ups) they have 3 (or more). Every *n* years they change their whole tooth-getup (maybe just the canines?) and need - for a short period - artificial teeth to enable feeding while the new set is growing usable again. The left behind ones are serrated because that is just how the vampire teeth are formed - the vampire saliva has healing capabilities so any rough edges are healed already when/if the snack-provider awakens. ]
[Question] [ Hydraulics commonly use mineral oil or water to provide the pressure needed for mechanical movement, which is good but the liquid just sorta sits there not doing anything else. So I though “why not use battery fluid instead” and with the addition of a cathode and anode voila! You have a system that provides movement and energy. **My question is painfully simple: is this a viable design choice?** I haven’t found systems that do this which leads me to suspect that this isn’t such a good idea. [Edit: I disapprove of comments that are basically answers. It makes it hard accept one or for answerers to answer without something being repeated. Just answer please. If you have something to comment then comment.] [Answer] The main equirements raised against a hydraulic liquid: 1. chemically inert against the materials used for the pressure "circuit" - you don't want corrosion of the pressure tubes and pistons 2. extremely low vapor pressure - must resist forming voids filled with vapors when the pressure becomes negative (and the pressure will become negative when you squirt liquids at high velocity through narrow valves - you get those voids as cavitation) 3. a reasonable viscosity - to keep the particles resulted from friction wear in suspension. 4. reasonable large temperature range in which the substance remain liquid. As a battery fluid, you need to: 1. have it conductive, with a good [electrochemical window](https://en.wikipedia.org/wiki/Electrochemical_window) and 2. *insanely clean from contaminants that throw a wrench into electrochemistry you are using for energy storage*. The viscosity part will play a bit into losses of energy by internal friction (thus, heating), so again some extra requirement for the low vapor pressure (which is approx correlated with higher boiling temperature) and chemical stability with temperature (which more or less correlates with the large electrochemical window). --- Now, there are some ionic liquids and deep eutectic solvents (good candidates to that fit the bill in regards with the battery fluid part) with [low vapor pressure](https://www.mdpi.com/2305-7084/3/2/42/pdf) (PDF warning - otherwise <https://doi.org/10.3390/chemengineering3020042>). Incidentaly, the low vapor pressure is good enough to make them usable in testing [whether or not a siphon works under vacuum](https://www.youtube.com/watch?v=8F4i9M3y0ew) - spoiler: *it sucks* perfectly. The potential problems with those ionic liquid/DES: 1. their hygroscopy - most of them are hydroscopic, which will play havoc on their vapor pressure 2. most of them really a very keen to dissolve metal oxides - which *maaay* play nasty with the chemical inertness against the elements in the pressure side, most materials have the "stainless" trait by the formation of a compact oxide layer on they surface. I haven't look exhaustively if there are safe combinations of metals good for high pressure applications and ionic liquids/DES (otherwise I'd probably be at the patent office instead of answering on WB). Then, *the battery function is going to be seriously impaired by the particulate in suspension and/or the dissolved oxides* - those will blow the capacity and integrity of the battery side in no time. --- The last problem stay at the fundamental side of your question is "multifunctionality". It involves a good amount of compromises and extra fluff to "just make it work" that you will get to sacrifice performance in all the functions that you put together. To illustrate, think at a smartphones: 1. mediocre as a computation device - we're still using computers for anything serious 2. mediocre as game platforms - we still have dedicated gaming consoles 3. mediocre cameras - you haven't seen a movie in theaters filmed with smart phones 4. mediocre communication channels - just go into areas without coverage to convince yourself In the case of "battery cum hydraulic device" - what do you want the most? Is it 1. to self power - and thus spare as much fluid as possible to coat your insane electrode area for power; *or* 2. to reduce the complexity of your pressure side of the hydraulics - thus forget filters that keep the electrolyte clean and require the lowers amount of fluid to move around? If you get a way that can work both, you'll get something that's good for all and excelling in nothing. This is not to be sneezed at, there will be a lot of applications where good enough is... well... good enough. ]
[Question] [ In my low-fantasy world wood is a very limited resource because all forests are haunted. Cutting a tree often means drawing the wrath of the creatures living in the woods, resulting in some very gruesome death. Exterminating the creatures in the woods is not even a possibility, because these places are ever-changing labyrinths and nobody who tried to enter them ever returned. So civilizations had to develop without relying on wood. I already read many questions about similar settings and found a lot of interesting ideas. Using rock or clay for buildings, fortifications and furniture, animal blubber or dung for combustion, and so on. But there's one aspect I wasn't able to find any elaborate answer about: transportation. In our world for thousand of years wood was used to build carts and boats and other ways to transport people and goods. And if in my setting rock is such an important natural resource, I suppose there's the primary need to find an efficient way to move it. I could just add to my world some giant turtles and say that people hunt them to use their shells as a material for carts, or stuff like that, but if possible I'd like to find some more grounded alternative. I suppose sea transportation is more or less impossible without wood, but about land transportation, is there some solid alternative that can be used? At a certain point of the timeline my plan is to make some societies reach a level of metal craft good enough to develop clockpunk technology, but before that how could they have transported for medium or long distances the natural resources they needed? [Answer] First of all people are always gonna have access to some wood. Steal a few seeds from a tree and you can start a tree farm. Birds and such can even do the work for you. There are birds (like the Blue jays) who are major distributors of trees because they often forget where they placed their nut stash, so instead of being eaten the nuts grow out into new trees. If the creatures of the woods wanna prevent this from happening they have to come out of their woods. So with that established do stuff like the incas to minimise wood usage; use pack animals, porters (carriers). That way you can even just use fiber baskets and such. We don't need carts, they're usefull, but humans can carry small goods, animals can carry slightly larger and heavier goods and for the really heavy stuff you've got rails or wooden logs (just look at how the Egyptians moved the blocks of the pyramids). The Incas and Mayas had one of the greatest civilizations of the ancient world and they didn't use carts. You can also use canoes and boats made of certain reeds like papyrus like the Egyptians did in the (early) bronze age. [Egyptian ships](https://exploration.marinersmuseum.org/watercraft/egyptian-ships/) Also are haunted forests fireproof, because forest fires can be rather easy to start even from quite far away? A dry period combined with the wind blowing into the right direction and well...just look at California or Southern Europe to see how far flames can spread in a short time span and remember those fires were being actively fought using modern equipment. People have been using fire for a long time to get rid off of unwanted wildgrowth. [Slash-and-burn](https://en.wikipedia.org/wiki/Slash-and-burn) [Answer] **Reeds! Skins!** <https://en.wikipedia.org/wiki/Kuphar> [![kuphar](https://i.stack.imgur.com/i2XXh.jpg)](https://i.stack.imgur.com/i2XXh.jpg) > > There were two major forms of construction used — hides stretched over > a framework, as described by Herodotus, and woven bundles of reeds or > basketry, waterproofed with bitumen. Boats of this sort were still > used in modern times, being described by British ethnographer James > Hornell in The Coracles of the Tigris and Euphrates (1938).[9] > > > Your people use bitumen aka asphalt to waterproof large, lightweight boats out of woven reeds and grasses. Smaller less labor intensive boats can be made by stretching a large hide over a frame. A bamboo frame would be ideal if you have bamboo. A whalebone or metal frame could work too. Shout out to St Brendan, who sailed to America in a boat made of bull hide! [Answer] Frame challenge - symbiosis rather than exploitation. Trees die. And rot follows. Any sentient species will eventually learn that the public health is better if you dispose the dead individuals in a sanitary manner. What better way than to donate the wooden corpses to those monkey descendants who can do the work and take a benefit from it? Humans - the wood carrion species. --- Note: > > because these places are ever-changing labyrinths > > > In the course of ever-changing the labyrinth, they can arrange the "diffusion" of dead trees in areas with low concentration, i.e. where humans live. [Answer] same hat! I have a similar situation in one of my settings [: Here's some ideas that helped with mine, as well as some I came up with for yours! * ***Tree Farms*** Haunted as the woods may be, an orchard or tree grow well within city limits might be out of reach for the things haunting your woods. This also opens up the interesting possibility of a tree farm that got too big, resulting in a haunting that ultimately destroyed the city. * ***A Deeper Understanding*** Sometimes, the way forward is through. The solution is not so ham-fisted as to exterminate the creatures in the forest nor to just give up on wood entirely, but to reach some kind of understanding with them. Some things must be taken. Not every tree can be ours-I mean, theirs. Maybe the people in your world only take two or three trees after extensive rituals and pandering to the things in the woods. A constant and slow cycle, ensuring that wood is used at the absolute bare minimum, and placed at a value alike to the most precious gems in the world. Our world's ships of solid wood would seem to them like one carved of marble and inlaid with silver and gold would to us. * ***Screw This, I'm Moving To The Desert.*** In a world with international trade, it's not totally outside the realm of possibility! Maybe wood is grown in more arid places without any forests to speak of, like desert coasts and the like, and imported from there. Most of the transportation is done with solutions purchased from these places where the only forests are 100% certified beastie-free. * ***Repell, Chop, Remove, Repeat*** In an adverse to pandering to the creatures, maybe the people (or part of the people; these shouldn't be totally mutually exclusive) of your world are short for time and really, really not into the idea of pandering to weird scary things in the woods just to get like two trees. They utilize things that repulse the haints of the forest, possibly ranging from magic to materials to even sounds, smells, or other sensory details that keep them at bay. By the time it's over, the people are long gone, and so are several of their precious trees. * ***One For Many*** Maybe it's more a debt than an immediate response, and this could tie into the cooperation answer listed previously. They cut down one tree, but they plant many times more than that, enough to placate the things out in the wilds enough that they can part ways with their one tree, since they now have so many new ones. Hope these ideas help! It's funny to see a question with a similar situation as mine; maybe my Lešovyk and your forest creatures can bond over their mutual love for forests and irritation over people constantly trying to defile their beloved woodland homes ^^ [Answer] Riding animals directly, only. No carts, just saddle bags & baskets. Metal carts. Copper tube skeleton with hides maybe? Stone carts. Eh. You could probably get away with it with a little fantasy hand-waving. Boats & canals. Others have covered boats elsewhere. Sliding stones a la Last Airbender's earth kingdom. Sliding stones only on ice. ]
[Question] [ I have a super advanced sentient species that is not human, and developing by itself on a planet. With such advancement, we expect them to think on a higher plane or at least in a different way to humans. And in the beginning they do. They live lives without issues of disease or religious conflicts or political issues or body image issues, etc affecting them. But then they come in contact with humans and a long drawn out conflict erupts between the two species. What could happen for it to now begin thinking like humans, the very species it is fighting? [Answer] ## A bunch of Reasons: I can think of a number of reasons that an intellectual, detached species would devolve down to a more brutal, vicious state when confronted with humans. * **Military Essentials**: Humans have the ability to kill other sentient beings, and issue orders for their machines to do so as well. I remember reading a novel where aliens sought out humans because they had lost the ability to kill, and they had a brutal enemy. To achieve the ability to kill intelligent life, they need to devolve. * **Broken Faith**: The aliens have a Pollyanna attitude about the universe. If they are good and virtuous, everything will work out in the end. Then humans showed up, claiming they were better (while clearly inferior), nicer and more virtuous (while lying, cheating, and killing). Those who hold to this Pollyanna attitude are killed, while those who renounce it live. Those re-adopting ancient vicious practices fight off the humans, and those who accept the teachings of the humans end up being more like the humans - fanatical and very intelligent, willing to kill either get ahead or spread whatever faith they have come to follow. * **Evolution**: Despite their apparent moral superiority, the aliens actually had a very primitive set of cultural practices centered around the traditional values of an agrarian society. They work together because they don't have a concept of lying and cheating (their ancestors thrived on cooperation). Now humans show up, introducing ideas like selfish interest, deception and greed. Suddenly there is a strong selective pressure for those aliens able to adopt these traits to out-compete their more peaceful neighbors. Kill your neighbor, steal his land, and take his wife as a second for yourself! Sure the humans are cheating them, but they mostly do it to themselves. * **Imitation**: If you don't know how to cope with human insanity, who does? Humans, of course. They seek out humans and see how the humans deal with these unique human problems. To see how they should treat inferior humans as a species, they look to our racial interactions. When they see how we deal with criminals, they deal with humans (and increasing numbers of deviants in their own ranks) with executions and prison. Do humans use bioweapons? Humans have a complex "health care system" to deal with such things. * **Undoing Domestication**: There is a theory that humans are part-way in undergoing a process of self-domestication, and that bonobos have essentially already done so to themselves. This process actually makes a species less intelligent but more passive by locking development in an earlier state. Under this theory, our ancestors were likely more intelligent and resourceful, but couldn't get along well and constantly fought. So in this scenario, humans are stuck half-way to domestication, but the aliens have gone all the way. Confronted with humans, the aliens must undo domestication (possibly by genetically re-engineering savagery) to make themselves stronger and more intelligent so as to confront the human menace. * **OOPS! We turned ourselves into killers**: On that same note, the aliens knew they were once stronger and smarter and could kill as needed. The reasons for these things being removed from their species are lost to history. They recover the genes for these traits and add them back into their genomes (recovering what was lost). Only after they've done so do they realize they have opened Pandora's box and loosed all the evils of their old ways. This new generation lacks the skills to deal with such behaviors and abilities, and they regress socially even further than humans as a result. [Answer] > > “If you know the enemy and know yourself, you need not fear the result > of a hundred battles. If you know yourself but not the enemy, for > every victory gained you will also suffer a defeat. If you know > neither the enemy nor yourself, you will succumb in every battle.” > > > ― Sun Tzu, The Art of War > > > In order to fully know your enemy and thus to defeat them, you must be able to think like them or at the very least to be able to simulate their thoughts to a sufficient degree so as to be able to predict their actions. [Answer] ## Dictatorships are fragile. The alien race formed a dictatorship, with everything being managed from a central hub with precise order and control for all to keep them in line. It worked fine for centuries, with their huge production powers being enough to handle any problems. There were outsiders with body issues, religions, politics and such, but they were on the fringes of society and no one cared about them much. When the war happened the over centralized society had some severe fuck ups and shocks. The members no longer trusted the central leadership to react well to their local situations, with core functions prioritized over their homelands, and severe tactical mistakes from a lack of creativity, quick responses, and order. However, the outsiders did great, and their creativity and lack of trust of the central government meant they succeeded. As such, they became the new nucleus's of alliances to fight the humans. If thinking like humans works, why not do it more? [Answer] **The aliens are absolutely nuts for human TV and movies.** [![i love lucy](https://i.stack.imgur.com/RpNjs.jpg)](https://i.stack.imgur.com/RpNjs.jpg) <https://www.closerweekly.com/posts/i-love-lucy-behind-the-scene-details-classic-tv-show/> Humans are hard to get along with. But dang they make great shows! The aliens acquire the vast trove of human TV and movies and they are hooked. Aficionados of various characters adopt mannerisms and catch phrases from those characters. Situations in TV and movies are found to have analogs in the doings of the aliens. Aliens approach each other and issues in their culture with the mannerisms learned from TV and movies. The aliens are infected by human culture. This would be very fun to write and even more fun as a TV show. Almost all the aliens have a favorite character. There would be an alien Ricky and in one episode it encounters another alien Ricky. [Answer] You've already modeled this life form as "humans on another planet". You do this because you yourself are human, and you model them that way subconsciously. Let's look at it objectively. They are *multiple*, but unlike bees or ants they have individual personalities (or at least, like humans, perceive themselves to have individual personalities). They are social. That is, they don't all run off territorial-like and become recluses on their own mountaintops (with the exception of mating season, when they seek out others). You're basically just doing an exercise in tropes. The trope is that they are utopian. No anorexia or religious dogma or genocides. But, much like some ancient morality plan, once they come into contact with humans they become contaminated by it, until they too fall from grace. If you need a good reason though, why, then it's just that they were already practically identical to humans before you even started to ask the question. You could strive to make them more alien, but if you succeed they won't seem utopian anymore. Instead, they'll seem totalitarian, terrifying. Maybe even demonic. So I don't know how to repair your premise to get anything out of that you'd find satisfying. [Answer] ## They won't. Unless those aliens are human. Humans think the way they think because they are biological intelligent beings that evolved on Earth, have two biological sexes (more or less), and share a common history. A lot of our stereotypes, biases, traditions, cognitive shortcuts, and so on are related to our evolution and history as species. It is hard to say how much is 'wired' and how much is a result of socialisation: Different schools of psychology will give you different answers. However, the absolute majority of them will agree that most of our behaviour is related to physical reality (environment, our biology, etc.). The best your aliens can do is an *imitation* of humans. I would not be surprised if much of this imitation were superficial. Moreover, it is very likely that the meaning behind this imitation will be completely different from humans. --- There is one possible solution: Your aliens are capable of morphing themselves and their environment. Over time **they do not start thinking like humans, they become humans**. This is similar to the Ray Bradbury's [*Dark They Were, and Golden-Eyed*](https://en.wikipedia.org/wiki/Dark_They_Were,_and_Golden-Eyed). ]
[Question] [ It is the not-too-distant future in an alternate timeline, and humanity has tripled-down on solar power. We built a network of solar focusing satellites that orbit Sol at close range (so they can capture more sunlight). "Close range" means somewhere between the orbit of Mercury and the solar corona. So, not as close as the [Parker probe](https://en.wikipedia.org/wiki/Parker_Solar_Probe), but still pretty close. The details of how they focus the light without being incinerated are outside the scope of this question; assume handwavium. These satellites focus light at a variety of targets distributed throughout the solar system to provide power, all of which have super-advanced solar-conversion tech aboard. The targets that get the most love are, in priority order: 1. Electric-powered "solar trains" on their way to and from Earth's space facilities. Each must be powered continuously for the bulk of its climb and descent. We have five or six of these at present. 2. Large permanent space stations near Jupiter, Ceres, and Saturn, whose batteries need to be recharged every month or so. (The colonies are primarily robotic, hence their outsized consumption.) 3. A giant solar-collection station in orbit around Earth, which charges massive batteries that we then carefully land on Earth. It demands power continuously, and can handle the light from 2 satellites simultaneously. It does not provide all the power Earth needs, but we want it to do more; the limiting factor is the number of batteries we have, and we're building more (subject to material scarcity). These satellites must be very hardy to survive so close to Sol, so building them is expensive and consumes scarce resources. Thus, we haven't built a bajillion of them; more in the neighborhood of two or three dozen. (Though that number is up for grabs.) We obviously want each satellite to have line-of-sight on as much of the solar system as possible for as much time as possible. Each satellite has a "firing arc" of 50° from its Solar radius (apologies if I've expressed that weirdly). So: what kinds of orbits are best-suited for these satellites? Here are a couple of obvious ideas, which (for starters) I'd appreciate help evaluating: * one evenly-spaced ring around the sun, in the plane of Earth's orbit * evenly spaced around the entire surface area of the sun, with orbits calculated to avoid collisions The biggest objection I can think of to the ring is that many targets will frequently be obscured by planets, leading to blackouts. The biggest objection to the second pattern is that the limited firing arc means that many satellites would have line-of-sight on nothing for a long time, which means we'd need to build a gazillion satellites (which we haven't), which once again leads to power blackouts. You might think that Earth can take a blackout because we have other sources of power, but the environment is near the breaking point, and the Terrarium Laws are absolute and totally merciless: anyone who tried to turn on a coal plant for even a few minutes would be summarily executed. If that means a hospital full of babies dies, that is what happens. The stations and the space trains really can't take a blackout either: the few people on them will die without heat and recycled atmosphere, and if station-keeping goes untended for too long, the station itself could be lost. If the solution requires a minimum number of satellites higher than what I've proposed, feel free to add them, but then I want some kind of demonstration showing that nothing lower than your number will suffice. Assume my number is 36. If the firing arc is unworkable, you can change that, too, subject to similar requirements about proof. --- Edit to add: there are no mirrors or lenses anywhere in this system. At least, nothing anybody would recognize as such. I said "handwavium," and that's all you're going to get (in this question). I think this would not evade the problem of etendue, but it should short-circuit a host of other concerns that answerers might get tripped-up by. [Answer] The approach is fundamentally flawed. Focusing optics, whether mirrors or lenses (realistically mirrors in applications like this), obey [conservation of etendue](https://en.wikipedia.org/wiki/Etendue). The incoming light comes spread across an angular area, and that spread still exists after passing through a focusing element. It works out such that for a mirror to just equal the sun's intensity, it must appear as large as the sun from the viewpoint of the target it's focused on. Your arrangement with the focusing satellites as close to the sun as possible is the worst possible case, maximizing the required mirror sizes. Equaling the intensity of the sun with this setup would require a mirror the size of the sun. A mirror at the distance of the moon would "only" need to be as large as the moon (which coincidentally has about the same angular size as the sun as seen from Earth). One in geostationary orbit would be about 3500 times smaller than one near the sun, with about 12 million times less surface area. Placing satellites near the sun only makes sense if the conversion is done at the satellite, and something else used to transport the power to its point of use. Microwave beams would likely be more efficient to generate and collect than lasers, but it's easier to get narrower beams with lasers. And even with these, longer distances mean more transmission losses and larger transmitters/reflectors, and it's unlikely that putting them as close to the sun as possible is the most effective use of resources. There's plenty of room in Earth orbit for big solar collector arrays, and you could easily arrange things so only a small fraction of the arrays could ever be in Earth's or the moon's shadow at any given time. [Answer] The biggest obstacle your mirrors will have to go around is the Sun itself, meaning that you would prefer a polar orbit for them, rather than an orbit laying in the ecliptic. When you are above the poles, you can sweep basically the entire ecliptic plane with your mirror as you please. If you are on the ecliptic, there will always be some portion of the sky blocked by the Sun itself. [Answer] Choice of orbit is an interesting topic, but.. **How to target high energy interplanetary light beams ?** Precision of the beam will be the main challenge and I even think it's a show stopper. Sending high energy concentrated light beams has been discussed in the past, when solar satellites in Earth's orbit were considered. Even from 100-400 miles altitude, a tiny direction fault of the beam would impose huge safety risks on the planet surface. Here you propose to send beams across the solar system.. such problems multiply. Even when the alignment error is extremely small, e.g. a beam gets 10e-11 degree misaligned, or your solar sat gets displaced 2 microns, because a dust particle impact. The beam will not hit the intended receiver, it can be miles off at the target. Also at this scale, take into account any gravitational fields in the path of the light beam (planets, moons) will bend the light beam and result in angle deviations. **Solution** As mentioned above, the easiest orbit (equatorial) has also the disadvantage of not being effective for >50% of the time. imho there is no reflected beam solution at all. Consider instead: storing the solar energy on the spot, by synthesizing some type of fuel in the process.. and then move that fuel out and distribute it, using robot spacecraft. [Answer] Shooting a moving train full of people with concentrated light from a far-off satellite seems like asking for trouble. I am sorry. I am shy at parties, too. Maybe I am too risk averse? Other ideas 1: **Satellites can bounce light to each other**. If you really like satellites beaming light, you can have one without a straight shot pass the light to one that does. 2. **Venus has lots of sunny real estate.** Huge solar collectors orbiting Venus could collect a lot of energy and if that cools down Venus so much the better. Or Mercury - you could have your plant on giant circumplanetary train tracks to crawl along in pace with the long Mercury day. 3. **Turn solar energy into fungible, portable energy ASAP.** You are charging batteries with it and that is good. Maybe charge those batteries on the satellite or on Venus? Or if you are really digging the cross-space energy beam, shoot it someplace no-one will get hurt when the beam gets frisky. Maybe Luna? The old beam scars of molten moonstuff will be interesting to see for new arrivals. 4. **Batteries shmatteries.** Batteries are fine but kind of 1970s. I am sure you can come up with more energy-dense near future methods to save solar energy. Different species of antimatter? Something even cooler (hint: make it "quantum"! That means it is cool.) Or retro - the moon has lots of aluminum. Aluminum metal is a great way to store energy and it is very stable. ]
[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/202476/edit). Closed 1 year ago. [Improve this question](/posts/202476/edit) I'm writing a short story set in an isolated, small community in an empty desert post-nuclear war (I don't have a specific amount, but I'd say around 110-200 years afterward). I was wondering what housing and other buildings would look like? They were all built by the people in the community. What materials would be available for them to build with? Thanks for any help! [Answer] # Mud [![enter image description here](https://i.stack.imgur.com/YeSxE.jpg)](https://i.stack.imgur.com/YeSxE.jpg) Much like old middle-east or african cities still in occupation today. In a post nuclear war world, presumably there is a severe deficiency in: * Manufacturing * Transport * Fuel * Machinery * Education That last point is essentially the major one: Expect educational systems to break down during the conflict and people returning to medieval levels of knowledge. Therefore one would expect the populace to use what is on-hand and that does not require any expertise and minimal maintenance. Plus Mud structures are well-suited to desert climates with thermal mass providing acceptable temperatures in environments with a high diurnal range. [Answer] **You'll need to make some decisions about the rules of your world... which is good!** This discussion is going to see-saw back and forth a bit so you can see where you can create rules to rationalize your world. First, note that 99.99% of the technology we enjoy today was invented in the last 150 years. You're estimating 110-200 years after the apocalypse. That's quite literally plenty of time to completely restore all of the technology we enjoy today. So, from a simplistic point of view, they'd have the same buildings you see around you right now. But your world is not simple! 150 years ago the world's population was about [1.25 billion](https://en.wikipedia.org/wiki/Estimates_of_historical_world_population). What that means is, all other things being equal, your apocalypse can wipe out almost 84% of the world's population *and (IMO) [you'd be at 1870 population levels with 2021 knowledge](https://worldbuilding.stackexchange.com/a/201208/40609).* Now, you can slow things down by wiping out more then 84% of the population — but all things are not equal! The consequences of a nuclear apocalypse can be great and varied. Not just radiation poisoning, but illness, genetic mutation (not the Spider-Man kind, but the "shortens your life" kind), lawlessness, panic, and the changes such an event would bring to the environment must be considered. That previous link points out that IMO it's very hard to lose knowledge. Books are everywhere (most knowledge is not yet entirely digital, despite what Google would have you believe). So are resources (stores and warehouses full of goods, old buildings made of brick and metal....). Whether or not these kinds of things affect your community depends on how massive the attack was, whether or not long-term-fallout bombs were used, how much of the farm/ranch/forest land (that not dotted with ICBM bunkers) was affected, whether or not major water sources (lakes, aquifers, etc.) were contaminated, etc. It's really important to realize that most bomb-made radiation doesn't last much more than 7-10 years (nearly all of the radiation from the tests in the 60s and 70s is [long gone](https://www.epa.gov/radtown/radioactive-fallout-nuclear-weapons-testing)). I've coined the phrase "long-term-fallout" to describe a bomb specifically designed to release radioactive particles that have a very long (50-150 years or more) decay rate. It's worth noting that it's unlikely (even unrealistic) that a nuclear war would actually employ such weapons. It's also worth noting that nuclear fallout is neither (A) contagious (you can transfer a radioactive particle from one place to another, but if something has been irradiated, that irradiation can't be passed to something else) nor (B) dense (it's not spread around like peanut butter, it's a dust, and there's only so much dust to spread around). **So, what buildings would there be?** There would be whatever buildings you want there to be based on the rules of your world and the conditions surrounding your community. After at least 100 years (and we know how fast humans can populate the world in 100 years from a known starting point!), you'd have metallurgy, mining, forestry... which means saws, nails, and hammers. Stick frame housing is very believable. Perhaps sheetrock less so (it would depend on how much your community's infrastructure had grown). Pipe extrusion was first patented in [1797](https://www.hoytcorp.com/blog/the-history-of-metal-extrusion/). Wire making has been around since (I kid you not) 3,000 BC. Simple generators aren't that hard to make and your community had 100 years to work on it. Concrete is frankly a given. Can you see my point about you making decisions? If enough people survived the apocalypse, you'll be right back to 2021 in the time frame you've provided. If enough people died and enough setbacks occurred, then you'll have stick frame houses (maybe log houses, but after 100+ years?). You need to decide how held back your community has been and how that happened. [Answer] Very few deserts are actually empty. You have a lot of choices, depending on the lifestyle and tech level of your people. Hunter-gatherers might inhabit places like Alta Toquima: <https://www.amnh.org/research/anthropology/curatorial-research/north-american-archaeology/projects/alta-toquima-nv> <https://www.thearmchairexplorer.com/nevada/alta-toquima-wilderness.php> Agricultural people might inhabit cliff dwellings or pueblos: <https://www.nps.gov/meve/learn/historyculture/cliff_dwellings_home.htm> <https://en.wikipedia.org/wiki/Pueblo> If they happen to be herders, then they might use something like the Navajo hogan: <https://en.wikipedia.org/wiki/Hogan> Miners might build something like this: <https://www.bodie.com/> And a more modern settlement might look like any number of rural Nevada towns, such as Goldfield: <https://en.wikipedia.org/wiki/Goldfield,_Nevada> [Answer] It is feasible to have a city in the desert, and you wouldn't *really* need to build it around some surface water. Groundwater exists in most deserts and while they would have to be dug deep, a well could provide water enough to satisfy the needs of a small community. Depending on the resources your inhabitants have access to, small houses made of mud, plus any other reinforcement material, would be the most likely option. However, 110-200 years is a long time, and unless they've been completely isolated since the war, they would probably be back to a somewhat normally functioning society, with housing similar to the rest of the world. ]
[Question] [ **Background:** Alendyias is a world that was formed inside the Fracture of Reality, one that is *still* forming as the Fracture in Reality grows and absorbs other worlds in its path. Absorbed worlds and all life in and on them are saturated with Chaos Energy, which in many cases turns ordinary creatures into monsters like trolls (formerly large apes) and goblins (monkeys). Chaos energy and magic go hand in hand (are practically synonymous), so various creatures have turned the Chaos Energy infusing them into something we call [Enchantments](https://worldbuilding.stackexchange.com/questions/196539/what-weapons-would-benefit-from-the-rubberizing-enchantment), a magical effect they hold during life and grant to whatever kills them upon death. (The link explains how this works for one specific monster, a slime-type creature called a Plop.) As an example, Cats may be Willful or Independent, goats may be Stubborn or Univorous (capable of eating literally anything). **EDIT:** To clarify, Enchantments are not just imposed by the Fracture, they are reflections of a creature's innate nature. If a creature evolves in such a way as to develop a new nature, it will develop a new Enchantment as well. **The trouble is, I need a creature that has Focus; a creature that can *control* the effects of any Enchantment it gains.** If it gets Rubberized, its teeth, bones, and claws will be unaffected but its flesh (plus fleshy organs, like heart and eyes) and muscle will be (because Rubberization would benefit those parts of its body). If it gains Explosive from a Cherry Bomb, it won't be doomed to explode but can instead exert explosive force when it chooses, leaping much higher/farther or striking with lethal force. **Enchantments are based upon a creature's nature, so a creature with Focus would need:** 1. Enough magical sensitivity to sense and distinguish the different magics inside it, as well as their nature and potential uses; 2. The intelligence and creativity necessary to harness gained Enchantments in a beneficial way; 3. A strong enough will (self-control, discipline) and sense of self to direct its inner magic ("I won't *let* this enchantment blow me up because *I* don't want it to, I'll make it do *this* instead). In other words, it must understand cause and effect and have the attitude and willfulness necessary to take control of its magic (or the Enchantments it gains) and bend it to its will. **In other words,** a creature with Focus must believe it can change the result of any magical force acting upon it (control the effect of magic upon it), come up with a more beneficial result than the natural result of the magical force acting upon it, and have enough willpower to make it happen. This of course makes it necessary for it to be intelligent, creative, and able to *perceive* the magical forces acting upon it, but that's covered in #1 and #2. Yes, I could just handwave this creature's existence, but all of my other creatures have a logical basis somewhere, so this creature needs one as well. Thus, my question is **How Can a Creature With Focus Come To Exist?** **Specifications:** 1. An answer must determine a creature that could evolve to meet the specifications above; ie. one that has the potential to either gain Focus upon entering Alendyias or could evolve to have the Focus enchantment. 2. An answer must also determine how the said creature would need to evolve to gain the Focus enchantment and what conditions are necessary for making it happen. **Yes, I know this is asking a lot. A creature with Focus would need to evolve a very specific and unusual mindset**, not to mention an unusual sensitivity to magical energy. The last one may evolve naturally, as natural selection will likely favor creatures that can sense higher "level" creatures (those with more potent Chaos Energy, so they can hunt or avoid them) and can determine the Enchantments on potential prey (to avoid getting killed by an Enchantment like Rubberization or Explosive), so that at least shouldn't be a problem. **I wish you luck, thank you for your input!** [Answer] **They didn't evolve at all, because they they aren't living creatures per se. They are extremely advanced machines from a forgotten past.** So before we begin, let's lay out what we want these creatures to do: according to your requirements they must be able to: * be able to keep track of all spells/magical abilities acquired, what they do and how to use them. * essentially human level intelligence in order to be able to not only use these abilities efficiently in their most basic form, but also to be capable of thinking outside of the box, coming up with new unconventional ways to use and even combine said abilities in order to achieve its objectives (despite the presence of other animals which are highly intelligent, I'd say humans are still the best example around of a creature with all of these, that's why I classify it as human level). * enough confidence, essentially to the point of absence of doubt, that it's capable of performing these tasks without flaw in order to be able to efficiently manifest these abilities. But what if these creatures weren't actually something that evolved naturally? What if they were made, BUILT by someone else who needed such a thing to exist? You said that Alendyas is a world present within a fracture of reality that's constantly growing and absorbing new worlds. However, if it has always been absorbing worlds, one of them had to be the first (warning, the following concept contains high levels of cliches regarding magical worlds with ancient civilizations, please bear with the lengthy text). Their origin is the following: one of the first worlds absorbed into Alendyas housed a species of highly intelligent beings much like humans in overall anatomy and physiology. While these forerunners (as I'll refer to them) didn't have a solid understanding of magic or any remarkable ability to manipulate it at first, they were incredibly advanced in the field of technology, and skilled in the art of robotics and artificial intelligence. Being now trapped in a world filled with creatures which at first would seem pathetic, but later prove to be very troublesome, if not lethal, as well as with a new, never before seen source of energy just existing all around, it'd be no surprise that these forerunners, being the only group of sapient beings around and with plenty of time after settling the proper fortifications, would immediately turn their attention to magic and start studying it, it's workings and how to use it to their advantage. Over time, they came to understand exactly how enchantments worked, how to exploit them and how to control the ways these would manifest, but there was one problem left: despite understanding magic and the enchantments attributed to its existence, they were almost completely incapable of harnessing it themselves, a problem they would bypass through the creation of **constructs**. Constructs were specialized machines, similar in many ways to pieces of armor, meant to serve as an extension of the forerunner, absorbing magical energy from the environment and transforming it according to the user's will. These became a part of the lives of many forerunners, with the exception of those revolted at their new life and contrary to the uses of magic. These constructs, at first simple pieces of gear with only basic AI meant to perform mostly simple tasks, became more and more advanced as time went by, until the point when the first **E.M.E** Unit was made. The E.M.E (Exploration and Monster Examination) unit was a particularly advanced construct with a clear purpose: to learn new information about the world and pass it on as well as to study the many monsters that existed. It was, at its core, a conglomeration of specialized nanomachines controlled by a complex AI capable of abstract thinking and advanced problem solving capabilities, as well as top notch magic conversion technology. Thanks to that, and the fact that it was essentially powered by magic, it was a being to be reckoned with, being incapable of becoming tired so long as there was magic for it to absorb. Even at its most basic level, it was already fairly powerfull, with its core mechanics being: * A process similar to digestion in order to acquire matter and base materials to replicate its nanomachines and repair damages sustained on its own, eliminating any need to return from its exploration mission for repairs and reducing the risk of destruction of the unit. * the ability to morph its body into weapons (for self defense) and tools (for collecting samples for analysis), as well as to alter its body shape and morphology into whatever form it deemed most efficient according to its surroundings in order to efficiently reach the locations it deemed as worthy of exploration. * the ability to absorb and control magic, using it as a power source, as a complement to its "digestion" and self repair mechanisms as well as for self defense in the form of simple attack spells. Due to its innate knowledge of magic and ability to manipulate it, it was also capable of controlling the enchantments acquired from monsters it killed, manifesting them according to its needs. Despite its might and potential in deepening the forerunners's understanding of the world, only one of these was ever made, due to the sheer amount of resources necessary to build a single unit, a great problem in a society with most of its infrastructure regarding the harvest of metals and other key components for technology being very limited. As a result, this souped up research drone worked for decades as the main source of information to the forerunners (which mostly remained in their city), learning and updating its programming and acquiring new knowledge, which it'd constantly relay to its creators. the many enchantments that it learned via various processes via trial and error, from consuming dead monsters to simply killing them to others, were also incorporated into its arsenal and database. Overtime, it learned how to use its repair ability and magical power to essentially reproduce, creating copies of itself as a means to cover more ground and to prevent the end of its mission due to unforeseen circumstances such as its destruction, at which point the units began transferring information to each other as well as to its creators. However, there's a reason the E.M.E unit is one of the only remains of the forerunners, and why their makers are nowhere to be found: The appearance of ideologies about some individuals being better than others, fights for power and disagreements with groups that were against the use of magic resulted in the rise of a gruesome Civil war, which destroyed most of their main civilization and drastically reduced their population, as well as causing them to separate into smaller isolated communities. These communities, now much weaker and incapable of recreating most technologies due to the loss of archives and destruction of supply chains for the necessary materials, were slowly wiped out by a mix of monster attacks, genetic issues related to inbreeding over several generations and extermination operations carried out by the E.M.E, being finally wiped out from history along with most of their knowledge and technology. As for the E.M.E themselves? They're fine and still active. Their creator, worried about the dangers that the forerunner technology could be to any future societies, entrusted the world to them, sending 2 last commands to the best of their creations right as the war began: " Defend your existence at all costs, and eliminate all traces of [forerunner's actual name] presence possible.". Now they roam the lands performing their primordial objectives: to learn all there is to learn, and see all there is to see. After this overly large, but (as far as I see) necessary origin story, I'd say the E.M.E check out all of your demands for a" focused" creature: * they have basic human level intelligence as well as the abilities to solve problems, be creative and think outside the box. * they are designed to sense and use magic extremely well in order to carry out their primordial tasks. * they have a strong enough will as they fully trust their programming and skill to manipulate their abilities and acquired enchants efficiently in order to achieve their objectives. They could potentially be able to make these decisions much faster than an organic creatures could as well. -it has an actual origin story on how it came to exist that isn't "one day it started existing out of nowhere and everyone just went along with it". So yeah. My answer to your question? ["Nanomachines, son!"](https://m.youtube.com/watch?v=RhMsboqMMzs), except these ones make up an advanced research/military superdrone from a forgotten civilization. It can technically digest stuff, it does have a protocol ("""instinct""") of self preservation and it can technically reproduce if they gather enough matter for it, so it's understandable why it could be taken as a very weird monster instead of a robot (especially when you know what a monster is, but not what a robot is, at which point you just call it a metal monster and start running). Now, if the creature **has** to be an actual organic being at all costs because the plot calls for it. Well they were extremely advanced, what is to say they weren't also very good at genetic manipulation couldn't simply modify one of the existing creatures to boost its intelligence and magic prowess/sensitivity? I'd not advise to give a species human level intelligence if you want them to be slaves forever though, unless you have a way to ensure they all have a thing for serving your species or something similar. Either way, it stopped serving, is out there now and helped with the forerunners' extinction so there are currently little to no traces of their presence in the past (unless you want to give your humans some cool advanced weapons without leaving the overall medieval tech level scenario). [Answer] **The creatures eat the magic** Assuming you have all this magic floating around you, something might eventually stumble upon a way to exploit the stuff. At first, it is just the cell that has its internal structure modified so that magic can go in, but not out. Then trapped magic provides warmth or energy that the animal uses. Then cells specialize in the same way the intestines and lungs specialize to get nutrients from food and the air (oxygen is the nutrient in the lung's case). In the same way you get thirsty, hungry, or out of breath, the animal would become magic deprived in any one of the storage organs that specialize to control specific types of magic. This would let them know what kind of magic they have and how much of it. **Smarter because of magic** The creatures then evolve to manipulate the magic. While it is not clear how or why intelligence evolves, it may be possible that intelligence evolves when being in a position to use tools or be smarter is advantageous. Magic is a tool that doesn't even require you to be intelligent to gain if you can just passively acquire it. If having magic and not using it correctly is dangerous, then creatures will gain willpower since the ones that don't will die, or more likely just evolve to not to eat magic. [Answer] **Magic Eating Flesh Parasite.** (Inspired by Charlie's answer.) The organism began as a colony of bacteria that eats ambient chaos energy. The same way plants feed off ambient C02 in the atmosphere. Bacteria can evolve much faster than macro-organisms to take advantage of a new food source. Colonies of this bacteria take the form of a mould in highly magical areas and on the corpses of slain magical creatures. Extreme amounts of the bacteria can cause an area to become less magical. Bacteria is known for having a 0 speed stat. So it was lucky some magical creature started eating the colonies. This led to the bacteria evolving to be parasitic, living inside the animal and feeding on the ambient magical energy of the host. The problem is this makes the host less magical, hence less able to keep itself alive. Parasites don't like it when the host dies too soon, as this makes the parasite die too. So the bacteria evolves to only feed off the magical energy that is not useful to the host. For example this means feeding off the Sharpen enchantment in the animal's flesh but not their teeth and claws, and feeding off the Strengthen enchantment in the shell but not the eyeballs. This actually makes the host more effective and makes the colony more likely to survive. **Bonus:** Colonies of this bacteria on their own have many alchemical uses to strip the magic from an area or individual. [Answer] ## Octopus Speculative evolution is not necessary, the octopus is already a really good candidate for what you are describing. An octopus is already one of the most intelligent creatures on Earth. Their capacity for making complex plans closely rivals that of humans, and even though they are not tool users by nature, they are very good at manipulating human mechanisms like latches and door knobs. In some ways you could even say they are even better at manipulation than humans when you consider the sheer complexity of their articulations. This level of intelligence will be important for how well your Focus creature can be conscious of how it manipulates magic. Their capacity for planning alone makes them a good candidate for focusing their powers, but they have other qualities that should meet your theme too. For starters, they already have rubbery bodies; so, instead of this being a magically inherited trait, it is something that is already true about them, though perhaps you could emphasise their rubberiness by giving them [Mr. Fantastic](https://en.wikipedia.org/wiki/Reed_Richards) like flexibility. Another good reason for the octopus is that it already has unparalleled conscious control over its whole body. Their peripheral nervous systems are so advanced than that they can reshape their bodies and control their skin pigments to mimic nearly anything that they see. So, when its body is imbued with magic, it would make since that an octopus would have a similar flexible control over that magic instead of the more single structure = single purpose way that rigid bodied animals would. [Answer] **if an enchantment is given to an entire animal, why not have more than one?** my idea is basically that a group of species with different specialized features became mutualists so as to allow simultaneous use of each other's features. an example it might have evolved from is the portuguese mano'war, which is a set of many different mutualistic species who work together as one. over time, they "figured out" that by killing an enchanted monster with only a specific member of the mutualist, it will only be transferred to the one member. this way, those who won't benefit/will lose from an enchantment wont be enchanted because they didn't kill the enchanted beast. since it evolved from a microscopic mutualistic system, the animals are extremely specialized for their mutualism and are all functionally the same. for example, there's one that acts as the muscles, inflating and deflating when other require it, another acts as the nervous system and brain, getting information from others and transferring it to those who need it, etc. thanks to a lack of anything keeping it in a specific shape, and evolving from a simple colony of species, its amorphous, allowing it to change which animals are exposed and thus which animals are enchanted. now, about the specific understanding of magical energy, its very simple: expendable organs. they have sacs with the sole purpose of getting an enchantment, giving data to the creature about what happened, and then dying as a backup of the organ produces a new one in its place. basically, once this strange beast kills something, it now knows about its enchantments, how they are used, and what they can be used for. over the course of its early development it'll memorize many different enchantments and once mature it can apply this knowledge to making itself as efficient as possible with its use. the reason for their intelligence is thanks to: as they evolved to gain knowledge about enchantments and apply it, they also evolved to learn how to apply knowledge, getting more and more skilled at taking data in and applying it in varieties of ways, and because of this, were able to understand many diverse concepts by simple observation and use of its expendable testing organ. eventually they figure out they can transfer knowledge better by having many colonies of these animals working together. this solution completely sidesteps the need to even have the focus enchantment, but to add it back, you can simply say that as these creatures evolved to make use of magic, their colonies also evolved to be more closely knit, eventually becoming effectively the same creature with just an extreme level of control over its entire body, so in response it eventually learned how to enchant its offspring, and from there how to manipulate the enchantments passed on, targeting only specific parts, developing an enchantment of its own in the form of Focus. (also sorry for making basically a wall of text) ]
[Question] [ Bringing this question over from Physics SE where it was closed: I'm looking for an 'as close to our understanding of current physics' doomsday scenario that results from something about the physics of the world changing subtly. The scenario ideally has three attributes: 1. The effect should be detectible/measurable 2. The effect should be progressive - not catastrophic until it goes past a certain point - whereupon the whole of existence basically unravels, or the universe is otherwise rendered inert or sterile. 3. The effect should have a runaway positive feedback loop, which is to say that once you've begun making this modification to physical reality, it becomes easier and easier to make MORE of that modification. 4. The effect MUST be cosmological in scale, hence why I'm looking at physical properties of the universe that, if tweaked, would catastrophically alter how physics functions. I am NOT asking for whatever technology should be the culprit, that much is decided upon (it's FTL travel). I'm asking for the specific attribute(s) of physics that it should be screwing with to plausibly present an existential threat to the cosmos. [Answer] An idea that gets tossed around a lot in this sort of scenario is [**false vacuum decay**](https://en.wikipedia.org/wiki/False_vacuum_decay). Let's say we have a tiny ball on the end of an ideal spring, moving back and forth as a harmonic oscillator. The ball and spring have some amount of energy $E$, and knowing the value of $E$ tells us something about the dynamics of the system. There's a quantum analog to this, the more abstract [quantum harmonic oscillator](https://en.wikipedia.org/wiki/Quantum_harmonic_oscillator). Again, if we know the energy of a quantum harmonic oscillator, we can say something about its dynamics. The one difference is that for the quantum system, the energy must be quantized in some discrete chunks, and we say that each possible amount of energy corresponds to a *quantum state*. We can order the possible quantum states like $|0\rangle, |1\rangle, |2\rangle,...$, where $|n\rangle$ represents the $n$th state. Note that there is a lowest-energy state, $|0\rangle$, which we call the *ground state*. In the case of a harmonic oscillator, it turns out to have a non-zero energy.$^{\dagger}$ Quantum field theory describes the universe as a set of interacting quantum fields, with each one describing fundamental particles (this is a slight simplification, but not by much). Each field has its own ground state, which is usually referred to as a [*vacuum state*](https://en.wikipedia.org/wiki/Quantum_vacuum_state) - and as above, we expect this state to be the lowest-energy state. Ideally, the vacuum state of a field is stable, but it's possible for it to be only *metastable*. This can happen if the vacuum state isn't actually the lowest energy state, but a so-called *false vacuum*. In this case, there actually is a stable lower-energy state, the true vacuum, but a field in the false vacuum state would need a nudge to get there, and without any sort of nudge, it'll stay in the false vacuum state. The aforementioned false vacuum decay is a scenario where, at some point in space, the false vacuum decays to the true vacuum through some mechanism like quantum tunneling. A bubble or sorts forms around this point; inside is the true vacuum and outside is the false vacuum. It is quite possible - thought not guaranteed - that a required critical condition will be reached where the bubble expands outwards at an increasing speed approaching the speed of light. Within the bubble, the laws of physics may be different in ways that prevent any significant structures like atoms from remaining stable; conversely, there may be minimal impact at all. Your conditions could be satisfied if we have a series of false vacuums, where the highest-energy false vacuum is actually several states above the true vacuum. At some point in space, this false vacuum decays into a slightly lower-energy false vacuum, causing tiny, non-catastrophic changes but also making it extremely likely that further vacuum decays will happen, each causing more and more severe effects. By the time the true vacuum is reached, the universe as we know it is no more. --- $^{\dagger}$The one-dimensional quantum harmonic oscillator has states where state $|n\rangle$ has an energy $$E\_n=\hbar\omega\left(n+\frac{1}{2}\right)$$ where $\hbar$ is the reduced Planck constant and $\omega$ is some frequency, so clearly the ground state has a non-zero energy of $E\_0=\hbar\omega/2$. [Answer] [Big Rip](https://en.wikipedia.org/wiki/Big_Rip) is another good candidate. [Dark energy](https://en.wikipedia.org/wiki/Dark_energy) is going to increase to the point that all matter in the universe is going to be ripped apart. Its downside is that if it's indeed going to happen, it will be billions or trillions of years in the future. But let's say we have strongly underestimated the dark energy. Let's say the dark energy is going to increase exponentially within our lifetimes. Then we are are going to see strange cosmological effects which progressively be out of compliance with existing science. The only explanation would be that dark energy is actually much stronger than we had assumed by observing distant (millions and billions of light years away) objects, and the universe as we know it would soon end. [Answer] You don't need to change anything in physics to have a runaway death of the universe scenario. You just need a [strangelet](https://en.wikipedia.org/wiki/Strangelet) to come into existence. > > A strangelet is a hypothetical particle consisting of a bound state of roughly equal numbers of up, down, and strange quarks. An equivalent description is that a strangelet is a small fragment of strange matter, small enough to be considered a particle. The size of an object composed of strange matter could, theoretically, range from a few femtometers across (with the mass of a light nucleus) to arbitrarily large. Once the size becomes macroscopic (on the order of metres across), such an object is usually called a strange star. The term "strangelet" originates with Edward Farhi and Robert Jaffe in 1984. **Strangelets can convert matter to strange matter on contact.** > > > Once a strangelet appears anywhere, all mass around it will eventually be converted into strange matter - even intergallactically. It's just a matter of time. The only thing keeping the universe as a whole from actually disintegrating thus is its expansion. For more information, see this video by Kurzgesagt, [starting at 3:52](https://youtu.be/p_8yK2kmxoo?t=232) (or watch the whole thing to learn even more about this bizarre thing). ]
[Question] [ This is an extension of [How Dragons Can Hoard People](https://worldbuilding.stackexchange.com/questions/193057/how-dragons-can-hoard-people/193186#193186), and it concerns something that I realized would be quite problematic: **transportation.** You see, dragons share the world with various other dangerous creatures, and they've found (because of these creatures) that leaving their humans unattended is generally a **very bad** idea, *especially* when one considers the dragon's nasty habit of stealing humans from other dragons. In the end, it didn't take long for dragons to decide that carrying their humans with them was the best idea since if one flew off to hunt something or take a look around, they might come back to find all their humans gone! But then a more insidious question arose: *how* to carry the humans? Carrying humans on the back was right out; then it might appear that they were riding them, and the dragons couldn't have that! Having the humans hang onto the dragon's spikes (if they had them) or limbs was also considered and rejected, as was carrying them with the wings or talons-dragons need those to walk, fly, or grab things, so active dragons simply need their wings and talons free. There was really only **one** good option: the mouth. However, the humans went absolutely crazy when the dragons tried to implement this executive decision, running in terror or collapsing in tears, crying "Please don't eat me! I don't want to die!" Even the humans who listened at first ended up opposing this plan violently... Apparently, spending most of one's life inside a warm, wet dragon's mouth is not appealing to anyone; yet there are people living in rainforests? Very confusing.... Anyway, the dragons would like to know: **How Can Dragons Get Humans To Accept Living Inside Their Mouths?** **Clarification:** 1. It is safe to assume these dragons have precise enough control of their body (and accompanying instincts) to carry humans around, in their mouths, without swallowing or hurting them. If they need to eat or breath fire, well, that's a whole different question right there..... 2. Once again, the dragons are not planning on eating (or inhaling) their humans; carrying them in the mouth is supposed to keep them safe. Draconic saliva is not acidic enough to cause damage to humans with sustained contact; if anything, it should *benefit* them. Furthermore, special membranes can close off the throat to prevent humans from falling into it or being inhaled. 3. Once a dragon is old enough to have its own hoard of humans, it is old enough to carry a village in its mouth. It might be a little cramped, but it's possible! 4. Obviously, dragons are beings of magic, so even carrying an *entire village* inside their mouth won't upset their balance in flight, which is heavily enhanced and stabilized by magic. (I mean, come *on*; how do you think a big, burly bat-winged lizard is even capable of flight of all things? Clearly magic is involved.) As always, your input and feedback is much appreciated, and if you choose to down or close-vote, please give me an explanation so I can improve both this and future questions. Thank you! (Oh, and if my tags are wrong, please let me know ASAP.) [Answer] Why put them in their mouth? You could just build a lot of bolt-holes inside any village your dragon owns. Should another dragon come knocking, all villagers will use the bolt-holes to hide. Some will naturally be caught and taken away, but if your villagers can give a description you can track them down and ask questions with tooth and claw. Whenever you leave them you can also ask some humans to pull sentry duty and warn others of potential threats, giving them more time to hide away and prevent kidnapping. In fact, why consider them into your mouth at all? As long as you are flying these humans in your mouth can't do their usual things like farm. So why let the humans hide in your mouth, if you can just order them to go into some hidden cellars somewhere and await your return? That's easier for your dragon and easier for your humans. [Answer] A Dragon lives forever, not so little boys. Unless, perhaps, they are moistened with dragon saliva? Maybe the health benefits include wrinkle reduction? Throw in Male Performance Enhancement and you will have suckers, erm I mean guests, lined up all the way around the block, or at least the Dragon. It will take years for anybody to prove this is baloney. [Answer] It's just a matter of doing it the first time and showing that it doesn't kill anybody. This has already happened with another flying object, curiously related to flames, too: the [hot air balloon](https://en.wikipedia.org/wiki/Montgolfier_brothers#Public_demonstrations,_summer_1783). > > On 4 June 1783, they flew the balloon at Annonay in front of a group of dignitaries from the États ″particuliers″″. [...] > > > The next test was on 11 September from the grounds of la Folie Titon, close to Réveillon's house. There was some concern about the effects of flight into the upper atmosphere on living creatures. The king proposed to launch two convicted criminals, but it is most likely that the inventors decided to send a sheep, a duck, and a rooster aloft first. The sheep was believed to have a reasonable approximation of human physiology. The duck was expected to be unharmed by being lifted and was included as a control for effects created by the aircraft rather than the altitude. The rooster was included as a further control as it was a bird that did not fly at high altitudes > > > Since the animals survived, the king allowed flights with humans. > > > Once one can show that humans can safely be carried in a dragon's mouth, more and more will trust it. [Answer] # Vore Fetishists You're right that *most* humans don't find the idea of living in a dragon's mouth appealing, but there's a minority of humans who find it *very* appealing. Seek out those people, and while they'll still need some convincing that it's safe, they'll be a lot more amenable than the general population. ]
[Question] [ *The atmosphere in the Judging Hall was stretched so thin that it seemed like it would snap at the slightest blink of an eye. On one side of the hall sat the Master Judge and his guards, his hand gripping a metal gavel that could either cause the greatest of pleasures or the most torturous of pains. On the other side of the hall sat the Defendant. Between them could be felt a great animosity, so powerful as to push the spectators against the walls; being pushed away from the emanation of hostility that - if one approached it - would force them to fall and curl up on the floor, to give up, to simply wait for it to stop.* *The Master Judge's gavel came down as if in slow motion, and crashed against the stone table with a force that would have cracked a femur in half.* *"Guilty."* *The eye had been blinked. The air was emptied by the reverberations emitting from the tremendous crash of the gavel. The great hostility disappeared, replaced by something even worse: the feeling that one's role had changed from predator to prey.* *The Defendant's face contorted. "I predicted this."* *He stood up.* *"I would expect nothing more from a man in the pockets of the Enemy."* *A gasp could be heard, and the guards were now on edge, with their guns at the ready. This was a very serious accusation. Almost all men who were found to be guilty in the Judging Hall would be at this point trying to be as sympathetic as possible to lower the severity of their punishment. Yet this Defendant was not doing that. He was almost guaranteed death.* *The Defendant's plans, however, did not involve death.* *From seemingly nowhere he pulled out a sword, and before the guards could react, he -* ...did what? What science-based superpower, in an otherwise superpower-free world, could someone have to make the sword a viable weapon in modern times? When I say *modern world*, it is likely the enemy will have common modern defense or attack equipment. Expect guns, bulletproof vests, tasers, and the like. (The character doesn't have to beat a tank, but the more overpowered you make the character while still keeping it plausible, the more bonus points you get!) The superpower itself must be science-based. It can be caused by natural or artificial causes, but please make sure it is feasible, not just possible! For example, a person who gets super lucky and whenever he uses a sword quantum tunneling makes it immediately go through the nearest person's chest is completely infeasible, because the probabilities are just way too low. Note that the character is not stupid. In fact, in order to develop the science-based superpower, it is likely he must have made some great advances in scientific fields, and therefore is most likely extremely intelligent. Before going into any situation, he would weigh up the pros and cons of other weapons - such as traditional guns, lasers, railguns, darts, bombs, or the like - and would somehow choose the sword. Why would someone do that? What superpower could they have, that would somehow make the sword a better choice than a laser or simply a gun? The materials of the sword aren't determined ahead of time. Pick whatever you like! However, it has to at least follow the *spirit* of a sword, even if it does emanate an aura of RGB and look pretty cool. Note that what makes the sword a better choice has to be applicable in the majority of situations. For example, when fighting in a fragile spacecraft a sword + inhuman reaction times might be a better choice than a gun to avoid puncturing the hull, but a sword must be a better choice not just in (rare) space-based combat but also in (common) ground combat. [Answer] *The Defendant's plans, however, did not involve death. From seemingly nowhere he pulled out a sword, and before the guards could react, he* ...raised it high. It was an absurd scene - not only was the very idea of a sword as a weapon completely insensate: the blade was actually a luminous plastic cylinder, and almost everybody present immediately recognized it as not a real weapon at all, but rather a sword-analogue from a very popular SciFi production of the recent past. "What *is* the meaning of this charade-" began the outraged Master Judge, turning a dangerous shade of red and raising his gavel. As if in answer, the blade began flashing irregularly. Everybody stared in wonder. What *was* happening? "The Defendant-" roared the Master Judge, and blinked. What-? He blinked again. He found it difficult concentrating. Something was happening, but - what? Who... and - *Now... that is curious* thought the Master Judge, suddenly puzzled. He looked again at his desk. *It shouldn't do this! It shouldn't be moving towards my fa-* The sword turned off in a suddenly silent room. Everyone present had collapsed where they stood. The Defendant opened the eyes he'd scrunched closed, looking around. "One hundred percent efficacy" he muttered, satisfied. The "blade" telescoped back again and he pocketed it. "Score one for the new discipline of photoneurology." --- **The science (and the science fiction)** It is well known that a strobing light at the appropriate frequency can [trigger a seizure](https://en.wikipedia.org/wiki/Photosensitive_epilepsy) in some forms of epyleptic syndrome. Lesser effects can also be achieved with both short-term and long-term exposures to specific wavelengths, for example yellow and white light has been investigated for depression and seasonal affective disorder. The possibility of inducing a specific neuronal firing pattern exists, even if the chances of this pattern having universal results in humans (i.e. everyone is affected in exactly the same way) are slight. In SF literature the effect has been leveraged more than once - for example in Peter F. Hamilton's *Night's Dawn* trilogy, and then of course there is Men in Black's neuralyzer. The one played by the Defendant is mostly the same trick - attract the attention with some flashy (pun intended) bauble so that the victims all look in the right direction and get the full effect, then induce a seizure. The effects we could get away with are: erasure of *short* term memory (last five-ten minutes; subjects don't remember much except *there was a sword...*); short-term forced compliancy to suggestions and orders - for example the Master Judge disclosing some access codes; [tonic-clonic seizures](https://www.hopkinsmedicine.org/health/conditions-and-diseases/epilepsy/tonic-clonic-grand-mal-seizures). Less likely but not unconceivable, induced personality changes and affective disorders. [Answer] I've posted a few similar questions about trying to make alternatives to guns work myself, but the truth is that it is extremely hard to make this work, and you probably can't do so practically. Guns didn't replace swords(1) because they are more lethal, swords are plenty lethal, guns replaced swords becuase they affect a vastly larger area(a 1-2 meter radius vs a 30+ meter radius). No justification or superpower can change this fundamental problem, and you'll never have a justification good enough to convince someone with sufficient knowledge about this issue. Like with the other similar idea of mecha working better than tanks or aircraft, stories that feature swords like this work better when they don't try too hard to justify it as actually realistic. The only example I can think off that I would say pulled this off is the Infomocracy series by Malka Older. In her story, there is a technology known as the Lumper that uses a tightly controlled magnetic field as an off button for guns. A similar idea could work here, in that your sword wielding defendant could have developed a similar toy and unleashed it in the courtroom at the same time he dramatically unfurled his sword. But here's the problem, even in Infomocracy, swords didn't replace guns. Flamethrowers and lower velocity plastic guns largely did. Even with bladed weapons, most character rely on more easily concealed and smaller weapons than a full sized sword. What also helped Infomocracy is that this element was not at all the focus, as the real story was about the concept of microdemocracy in which "nations" are merely 100,000 people centenials, forming coalition governments attached by ideology rather than geography. It is also about the group Information who run said system, as a hybrid of the United Nations and Google, with all of the unfortunate implications that combination gives. (1) More accurately guns mostly replaced spears and other longarms, as swords were the equivalent of modern handguns as the classical sidearm. This is why swords could still be found up until the first world war. [Answer] ## Defining Plausible: I'm thinking this is likely a frame-shift. There are several reasons where this could apply, but you might not agree with them. I'll lay them out. Only the first is really plausible. * **Legal**: Guns are banned. Although a sword is potentially lethal, it's nowhere near as bad as an assault rifle spewing bullets into a crowd. A massacre now requires dozens of armed men, not a random crazy. Maybe it's a reaction to horrible events, or religious, or imposed by aliens. That is up to you. Computer systems (if they are universal) have been engineered into all police bots and systems so that no one can carry a gun. They will be automatically be arrested. Folks can perhaps carry other projectile weapons, but if they get too fast/gun-like, you trigger the universal response. The response could be hard-wired into all computer/social systems SO deep the authorities can't/won't be able to adjust it. So Beat cops are carrying clubs and rapiers, pepper spray but not tasers (too gun-like). You *might* get away with a compound bow, but a crossbow triggers flags. My vision on this is that an AI is built to enforce laws and judgements independent of human influences. The AI becomes fully aware and takes over the entire global internet. Rather than ruling the world, it ruthlessly enforces a series of laws that matches ITS idea of human interactions. Surprisingly, the system works extremely well and everyone universally agrees the AI is dong an amazing job. Lethal violence drops, and wars become VERY different affairs. But the AI doesn't allow guns. ANY guns. Every person who uses one has their money and lands seized, drones attack them on site, even doors won't open for them and they become pariahs, escorted to prisons to serve time for their crimes. * **Audacity**: Does anyone think Batman couldn't stop more criminals if he was a sniper, swinging from rooftop to rooftop shooting people? Does anyone want to read that story (okay, that's more the Punisher)? If you have ANY superpower allowing you to get close to your enemies, the sword is a classic tool, terrifying in its simplicity, intimate in its violence. Sure, you can spray bullets and plant bombs. That makes you a thug, or worse, a terrorist. The CHOICE of a sword is a deep statement of contempt for your foes. EVERYONE knows you can do worse, and don't even bother. Like Batman, it's a mind game. To put it differently, imagine a scenario where you have to go through one of two buildings to escape from somewhere. In one, there's a gunman. In the other, Hannibal Lecter. Which building are you going to escape through? * **Handwavium tech**: Force fields don't have a great real-world place today, but who knows what science will bring? They're so universally accepted as a fixture in stories that everyone suspends disbelief. Similarly, being able to shift an object through space means either that a blade could remotely strike an enemy OR a person could teleport to their opponents and engage at point-blank, overcoming the advantage of ranged weapons. Similarly, a teleporting device is too small to fit in a bullet, but a sword will do whatever you want (and then teleport back to you on command). Ironman-type super-armor might make bullets ineffective and allow closing. * **Handwavium materials/properties**: There were nanoswords in Deus Ex that were super-sharp, able to cut through almost anything. I've seen sonic hand weapons that can cut through structural materials in various books and games. Adamantium is over-done, but includes that combo of "invulnerable to anything but adamantium and able to cut everything else, but too expensive to use for bullets" that appeals to a hand weapon (maybe more of a light sword, but still). If there is a material that is conductive to a new type of energy, even a thin filament of it could give a sword amazing properties (leading to my next answer) * **Psychic-like (extradimensional) abilities**: The mind and perception become increasingly important to manipulating the deeper levels of theoretical physics. This is getting increasingly far from your suggestions, but if there are extradimensional components to advancing technology (like the intervention of beings who's interaction with our world differs radically from ours, or people able to shift into different kinds of reality) then the world is wide-open. Manipulate probability, and every bullet misses. But a human stabilizes reality around them, so attacks you continue to control get through, and interacting fields disrupt such that a sword can penetrate (although a bullet might still work point-blank). You can't change what is easily perceived, and so bullets must be seen to stabilize. Draw extradimensional energy psychically, and you can channel it through something you touch, but not through a projectile (so that giant sword can cut through a tank, but an RGP is stopped by advanced armor). Obviously this can apply to the teleporting/forcefield handwavium as well. [Answer] **Lets start with what we know. This sword came from *nowhere*.** /*From seemingly nowhere he pulled out a sword*/ Defendant is a dangerous dude. They would have checked him for weapons, and I mean checked him. He would be wearing prison clothes. There is nowhere to hide anything much less a sword. Yet he produces a sword. Either the sword sprung out of nothing and he created it. Or the sword was *nowhere*, and has come to here at his request. **The sword is a gate.** The sword is an access to another place. Maybe a certain place, or an uncertain place. It might be part of that place. Maybe a place that connects to many places. The sword may be the 3dimensional extension of a multidimensional object which can be used to traverse these dimensions. Why a sword? The persons who originally devised this item intended it to be used as a weapon against entities that were very difficult to hurt, much less kill. But they could be moved, and being struck by this sword can move the thing struck to *nowhere*. He could use the sword to fight. But the Defendant does not intend to fight. He intends to escape. > > From seemingly nowhere he pulled out a sword. As his guards reached for their own weapons, the Defendant spun the sword, grasped the hilt with both > hands, and thrust the point against his midsection. It burst bloodlessly > through the back of his prison shirt as he groaned and folded over the > blade. And folded. And folded, somehow becoming smaller and smaller > until he was gone. > > > The Defendant brings himself *nowhere*. It is a neat trick. However, a problem with nowhere is that it is not empty. Other things too durable to kill have been sent there by the sword over the years. Some of these things are also too durable to die, and they remain, and they remember. [Answer] Starting with the fact that your character seemingly pulled a *sword* out of nowhere, the fact he's in a courtroom and was just called 'guilty' by a judge, and the mention of an "Enemy" I have to say this is perfectly feasible, *as long as you've set it up correctly.* I created a blade-wielding character named Cobalt that can take on (and take *out*) gunmen, so perhaps I can give you some needed inspiration. 1. Taking a Weapon Past The Guards-This is a *big* deal; how would someone get a *sword* past the guards who would have searched him before he entered the courtroom? In Cobalt's case, his swords are an extension of him, formed of his essence, so he can absorb them into himself when he doesn't need them then reform them in his hands when he does need them. 2. As for "*before the guards could react, he....*"-Cobalt's blades are bulletproof, and with his razor-sharp reflexes, he can block, deflect, or slice incoming bullets. This combined with his supernatural speed and strength allows him to take on gun-wielding opponents *despite* the innate weaknesses of swords against firearms. 3. Plausibility-Ever heard of quantum foam? If that's possible, why not crystals made of entropy (disorder)? This is basically what Desonia is, and Desonia is what gives Cobalt his supernatural powers; it links body and mind and manifests both in supernatural ways. For Cobalt, this means his swordsmanship becomes the Implausible Fencing Powers trope. You could do something similar for your character; *something* in his system warps reality in such a way that he *can* use a sword despite its inherent uselessness against firearms. [Answer] Simple: Give the sword some sort of ranged-weapon capacities (maybe it splits in two to reveal a gun), and enough cutting power to cut through materials used for modern body armor and tanks. [Answer] ## Why use the sword. Reasons 1. Confusion: This days no one would expect you to jump on them with a sword and it breaks the modern way of fighting of fronts. 2. Friendly fire: You could trigger your enemies to fire among themselves in the confusion and use them as human shields. 3. Demoralization: First you see a dude killing you heavily armed pals with a sword then you even kill your own partners(that are being used as human shields) it would scare any one to dead. 4. Preferences: Your protagonist simply doesn't like fire weapons. 5. Is personal: No logic here he just wants to kill up close and personal. ## Why use the sword. Making it viable (Science) I believe that with tech this is easier to explain that the reasons. You could come up with mostly whatever you feel like, this are some ideas: 1. Kinetic shield: It doesn't needs to stop bullets just deflect them. 2. A more advanced armor than normal: Have you heard about graphene, it's a new organization of carbon, is extremely durable, light, hard and flexible is being called the future material, better yet it exists look into it. In the future it may be used to produce just about anything including body armor and mono-atomic sharp blades, it's so cool that it sounds like science fiction but it isn't. 3. Time acceleration: It's theorized that time has particles. If you could excite this particles you could move seemingly at supreme high speeds while for you it would look like everyone else is moving slowly. [Answer] \*\* Invisibility \*\* While not possible with current technology, we can imagine what would be required to give at least near-invisibility to an object. That is, receive and identify exactly what light is coming in at what angle somewhere on the object's surface, absorb that light, and emit the same light "on the other side". The computing problem to analyze everything coming in at every point on an irregular surface would be significant, and the materials problem for absorbing and emitting light on command might be even harder, but if you put it in these terms, you're at least science-based. The advantages of invisibility as a super power are pretty clear; you can avoid being targeted (other than by someone randomly spraying bullets), and you can get close enough to a target to wield a melee weapon without being percieved (visually), or defended against. Why aren't you turning invisible and shooting? Well, you have to make an excuse or two here, but there are some.e plausible ones. Maybe loud noises disrupt the advanced materials of your suit. Maybe extending the cloaking effect to "a gun" is difficult, but some custom-made melee weapon is easier. Would a sword specifically be better than a club? If spatters from blood stand out against your invisibility, a sword has a distinct drawback in that you're more likely to be spreading blood around. On the other hand, if the invisible material is sensitive to harsh vibrations (like the noise of a nearby gunshot), beating people will definitely disrupt the cloaking effect. Also, you're much more likely to be lethal in a single blow with a blade. Thinking in the other direction, swords have more reach and can be more lethal than a knife - but maybe extending the invisibility to a polearm is difficult or impossible. Plus, you can't see your own weapon (it's invisible), so you don't want to be carrying something that might catch, because you don't see the end of it. A sword is a good compromise in weapon size. As usual, we'll ignore the fact that invisible things are (probably) blind. [Answer] **The culture** <https://en.m.wikipedia.org/wiki/Jack_Churchill> This man thought you couldn't live without it. It is a symbol and can inspire a great deal of emotions in the people seeing it. A gun is scary, a man advancing with a huge sharp piece of steel is quite another. **The science** This man doesn't want to die and is intelligent. The sword can be made from different materials, like a graphene or crystallised or possibly a composite of materials that make it possibly better than a normal sword. In addition, it's not detectable by metal scanners. This still doesn't make it effective against cool headed people with guns. The sword has a scientific form of bio luminous layer on top that can flash incredibly bright to blind or confuse attackers. Together with a lightning fast version of the glasses that turn into sunglasses depending on the amount of sunlight, possibly in lens form, the sword wielder has a much more easy free movement across rooms. Due to the size and composition of the sword it can last a long time. **Problems with a sword** A sword can't really be better than a gun. If you have lightning fast reflexes to use a sword, using a gun tailored to the situation can be better. In space it isn't difficult to make guns that are dangerous but don't damage the hull (significantly). You can grab tasers as well! With guns don't need to cross distances and they require low skill for operation. That is what most military is doing. Making weapons that can be as effective as possible with as little training as possible. Sure there are exceptions, but even with high skill stuff like planes you see we're replacing them with drones. No more hours upon hours in simulations and training. Just courses on commands to the UAV and validating targets. So a sword is in the modern day not really valid. It could be valid uf other options lose effectiveness, like with special shields. Still, the sword can be good for your character, even if it isn't the best choice available. ]
[Question] [ **Background:** Agent Jones is pretty close to being peak human: in physical contests he wouldn't win against an Olympic medalist in their discipline but he's easily above the 95 percentile when it comes to fitness. In terms of mental skills, he's sharp and has two decades of exemplary in-the-field secret agent experience. He also lives a very regimented life with exact rituals concerning what, when, and how much he eats, how long he sleeps, when he exercises, when he shaves, etc. Needless to say, he knows himself and his body very well. **The Scenario:** Somehow, the evil bad-guy syndicate gets the jump on Jones, and the last thing he remembers before waking up is getting manhandled into a private jet before fading into a drug-induced unconsciousness. Now he's woken up in an interrogation room. **The Question:** Being as in-tune with his body as Agent Jones is, can he estimate how many hours or days he was knocked out by the amount that his hair, specifically the stubble of his normally clean-shaven chin, has grown? What level of accuracy can be expected for this estimate? [Answer] Running my hand along my face, a few hours after shaving, I feel I can detect the individual hairs. Waiting 10 hours, yeah I can feel more. Next morning, oh lots more. I'd be very confident that I could learn that pattern, especially as it grabs on my hand as a drag it over it, and use it to estimate with good certainty how much time had past. Pity in this case, I'd be wrong. **Sleeping men grow beards faster than conscious men.** 1. [Facial hair growth is proportional to testosterone levels](https://www.healthline.com/health/beard-growth-fast) 2. [Testosterone levels increase when you're asleep, peaking during REM sleep](https://thesleepdoctor.com/2020/02/01/how-sleep-impacts-testosterone-and-why-its-important) If your agent has been asleep for 24 hours, and he was drugged 3 hours after he shaved, his beard will be slightly longer than it would normally be at 27 hours after a shave. (I'm guessing he'd say it felt more like a 36 hour beard, but it depends on how the knock-out drug worked. Did it put him to sleep? Did he REM?) However, when he's knocked out (eg due to a concussion or injury), his [Testosterone level will drop, by up to 70%](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5816813/). This can also occur with [Alcohol or other things which knock you out chemically](https://vertavahealth.com/alcohol/testosterone/). He'll wake up 24 hours after being knocked on the head and guess from his beard he'd only been out for 12 hours. He would be highly certain of his prediction - I reckon he could learn to predict it within an hour if he does know his body that well. He'd be quite surprised at how wrong he would be in this case. (He also could've been knocked out for months and the bad-guy shaves him the day before withdrawing the IV.) [Answer] 0-24 hours is easy; most men who shave can estimate within around 6 hours by feel. 1-3 days is pretty easy for me to determine number of days (but nothing more precise) by feel. After that, it's just "scruffy" and hard to gauge by feel. For longer periods of time, Agent Jones needs to know his beard's average growth rate...and have a ruler handy...and perhaps should take an average of 10-or so hairs, so perhaps a bit of scratch paper. ]
[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/182792/edit). Closed 3 years ago. [Improve this question](/posts/182792/edit) Science fiction is full of devices allowing people to open portals to other worlds, teleport, open wormholes, etc. but there are only subtle discussions about tapping into the sun or other stars with the same technology, usually as a weapon (often teleporting an enemy into said star). Civilizations spend vast amounts of time generating fusion, collecting solar radiation, manufacturing antimatter and the like. If your civilization has an FTL device allowing you to essentially open portals, then why don't they open tiny portals into stars and vent off some of the superheated material to power spaceships, direct outward as plasma weapons, or even run planetary power grids, etc? Why not even use this as the thruster for a spaceship as they travel with conventional engines? A big enough portal could move planets. I don't know if this would work, but draining the core of a star might extend the life of the star by cooling the fusion or venting the heavy elements that speed fusion, not to mention generating billions of tons of matter for any project. **What is stopping all these sci-fi worlds with teleporters from tapping the virtually unlimited power source instead of harvesting or manufacturing expensive, complex fuels?** Is it containment? processing the energy into a useful form? Too much, too fast? If using the portals took insane energy levels to open, they wouldn't be practical to move ships and people. Hard science answers would be good, but I'm not tagging it as such because all answers are welcome (especially since portals are already handwaving). [Answer] It's not unknown in SciFi to use such power sources. *Star Trek* canon states Romulan spaceships are powered using a controlled singularity. However... **Heat** And just to make things interesting... the sun is hot. Now, to be fair, theoretically nuclear fusion is hot, so the temperatures shouldn't be any more difficult to control. But I'm throwing it out there because, whatever tech is being used to open the portals in the first place... well... the sun's hot. Maybe this one isn't that big a' deal... so I got it out of the way first. **Gravity** The gravity of a sun is non-trivial. Opening a portal that deep into a gravity well would have... consequences. That portal would let energy through, but it would also want so suck the ship it's powering into the star. Dealing with the gravitic shear would be impressive. **Pressure** Just as gravity is trying to suck your ship through the portal, the sun, itself, is trying to push itself through. Think "ew! Popping a zit!" on the scale of gazillions of megapascals. So, now we have a shell around the portal that's trying to keep the ship from being crushed like the proverbial beer can from gravity and popping like ants on a hot plate from the outward pressure. **Motion** The star is in motion. The ship is in motion. Those two motions aren't usually compatible. Some authors have used this in their stories (Larry Niven's *Ringworld* stories come to mind), and it's an issue you'd need to deal with. As the ship changes relative-motion vectors with the star the energy being pumped through the portal would change and the portal itself would have problems. If you're going to be real about this, the stream of energy would be anything but constant — and motion is one of the reasons why. **Activists** Just to reflect the "real world..." *activists!* "Turn and run! Not my sun!" Whole civilizations may protest the use of their sun to power your spaceships. Who cares if you're reducing the life of the star by a measly twenty minutes? "You've gone too far! Not my star!" [Answer] I can't speak for what goes through science-fiction authors' heads, and I can't really help you find out why an author made the decisions they did. What I can do is give a handful of ideas for a world in which this doesn't happen, and why it might not happen. --- * Portals can only open or close in vacuum. While objects can pass through a pair of linked portals once they're open, the process of opening them requires as little molecular interference as possible, as turbulence or collisions on either end will disperse the connection. Stars have a lot of potential sources of interference. (Similarly, such an explanation also prevents "portal cutting"; if there's a significant amount of matter passing through, you can't close a portal, so be careful opening one up inside an octillion tons of matter!) * You need structures at *both* ends of your intended connection to open a portal. Generally speaking, it is somewhat difficult to make a ship capable of swimming through super-dense plasma hotter than the melting point of basically any known material. * Portal structures cannot handle the conditions of having uncontained plasma surge through them. Perhaps the structure that contains a portal on the opener's end has temperature-sensitive functionality, or simply has to be made of materials that melt at less than 10,000 K. I would imagine that a structure linking two points in space needs to also resist vibrations, else things might get distorted or ripped open as they come through; a high-pressure jet might not be safe to handle without exceeding safety tolerances. * Portals conserve energy in some way. Moving a spaceship from one point far from any gravity well to some other similar point without changing its velocity involves a very small change in the ship's total energy, which you need to put into the portal structure. Teleporting someone down to a planet from a ship in orbit subtracts their gravitational potential energy, so it conveniently goes back into your portal system to be used for the return trip. It takes a staggering amount of energy, meanwhile, to drag huge amounts of matter all the way out of the gravity well of a star. Unless you're able to drop some asteroids in (and your power systems can handle the surge) to build up enough energy, you're not going to be getting much plasma out in return. [Answer] In Charlie Stross Novel *Glasshouse*, there is a weapon that essentially opens a tiny wormhole into a star for very short amount of time. It even exists in handgun form (though IIRC it's more of a directed explosion than a shot). The *Singularity Sky* 'verse by the same author also features wormholes and FTL, but since black holes can also be manufactured (as a component of some FTL drives) and managed these are used as power source (via hawking radiation I think), so there's no need to directly harness a sun. The possibility to use the FTL technology to manipulate a star is used to interesting effect in *Iron Sunrise* (Same 'verse): > > In this Universe, FTL implies time travel and the space nazis have the far future version of a star travel back into itself, causing an instant supernova because of the sudden mass influx. > > > In Iain M. Banks Culture novels, such a weapon does *not* appear AFAIR - instead, warships use their teleporting ("Displacement") ability (in Universe explained with wormholes) to position missiles in good tactical position, or to teleport Antimatter directly into or onto the enemy. It's hard to answer why authors write the way they do. My pet theory is that many stories are not written as an exploration of more or less fictional possibilities, but start with certain tropes the author thinks are cool or helpful to tell his story, and the worldbuilding walks backward from that. ]
[Question] [ I'm working on a creature that uses predominantly its clawed arms and sharp teeth to hunt down prey. The creature is bipedal, is around the size of a large lion and has similar strength, but greater speed (it's in transition to becoming a pursuit predator). Its habitat is predominantly composed of open plains with tall grass, but with more trees and richer soil than what we find in the Savannah (there are trees which are much larger and more developed, but they aren't important in this case). I'd like the creature to have a strong enough neck to allow for ripping flesh from its gazelle-sized prey, but since its eyes are fixed in the skull (it relies mostly on vision to hunt, and has large eyes), I'd like them to also have a neck rotation range of about 270 degrees in each direction (similar to an owls, as they too seem to have evolved it to compensate for their fixed eyes). I haven't decided on the length, but I planned the neck to be composed of 14 vertebrae. Given this, can a creature have a neck capable of such rotation without overly compromising the overall strength of said neck? The best natural example of such rotation is owls, but their necks seem rather skinny, and their mandibles and beaks aren't usually used for hunting. [Answer] You basically just described therapod dinosaurs. which come in a range of balance of claws and teeth to choose from. They come in a range of sizes and hunting styles. Here are three examples, *Allosaurus*, an oviraptor, and *Deinonychus*. [![enter image description here](https://i.stack.imgur.com/vQk2k.png)](https://i.stack.imgur.com/vQk2k.png) [![enter image description here](https://i.stack.imgur.com/fN9Aw.png)](https://i.stack.imgur.com/fN9Aw.png) [![enter image description here](https://i.stack.imgur.com/ogmiT.png)](https://i.stack.imgur.com/ogmiT.png) Predatory birds and dinosaurs have/had strong flexible necks. 270 degrees is actually not that flexible, many mammals can pull off near 360 ranges of movement laterally, and about 180 vertically. some birds and dinosaurs birds can do even better. [Here is a great video on the range of movement of bird necks](https://www.youtube.com/watch?v=uvNxFnTfrak). Mammals have this less often because mammals are missing a whole set of neck bones (cervical ribs), which add a lot of musculature to the neck of animals that have them. but there are plenty of mammals with strong flexible necks too, wolves come to mind. There are [extinct birds](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0037701) that hunt only with the head that can give some some ideas. [![enter image description here](https://i.stack.imgur.com/pRwBj.png)](https://i.stack.imgur.com/pRwBj.png) if you want a neck to be flexible it has to be skinny, thick necks evolve to limit the range of motion not increase it. It would help if you were more clear with what you want, many bird have eyes which cannot move or move very little. [Answer] Just so you know: some breeds of dogs can turn their heads more than 180°. Just not the way you are thinking. ![A dog looking backwards by bending its neck, heads stays topside down](https://i.stack.imgur.com/HUSwO.gif) The neck of a dog is very muscular and strong, being more akin to a human's waist than a human's neck Canids and felines can also rotate their heads nearly 180° in a similar way. ![A lion lioking back](https://i.stack.imgur.com/qrfAJ.jpg) source: <https://www.mikerae.com/young-lion-looking-back-from-tree-panthera-leo/> This allows them to turn their heads 360° already. Turn 180° one way, then another. Once you've done that there is little advantage in going much over. This is more for their eyes than their ears, though. Canids and felines can usually rotate their ears in most directions and independently, and the former even count more on their hearing than their sight. This makes it less likely that a neck rotating more than 180° would be an advantage. Predators such as these need strong necks to withstand being bitten in fights, and to withstand the forces they will expose themselves to when they are biting prey. A neck that could turn further would have to be thinner and more delicate. Trust me, your predators are already good (and believable) with a dog or cat neck. [Answer] What you need is a carnivorous horse. A horse's neck is quite flexible, able to bend nearly 180 degrees left or right - enough to scratch or bite itches on its belly. Do an image search on something like "horse looking backwards". It's also very strong. [Answer] I think you mean the question to be "How" I was drawing everything, but then stack exchange told me the images were to big, so whatever I will try to explain it with just words. You need to remove some infra vertebral muscles, not because it would make the neck more flexible but because it would leave free space, and we need a lot of space. A necessity will be to take all neck muscles and put them on the back, this gives you the ability to make them larger, suddenly the trapezius become larger than the latissimus dorsi. All the neck muscles will be connected to the spine the same way fingers are connected to the forearm. I don't know much about flexibility, But I know that in some causes excessive flexibility comes from weakness in muscles and sometimes excessive stiffness comes from muscles which are too strong. From training the iron cross on rings I popped my elbow because my biceps were too weak and now elbows bend backwards, on the opposite many professional arm wrestlers can't physically extend and straighten their arms because the bicep is too strong. Both situations can be avoided by making antagonistic muscles stronger. Muscles from all sides of the neck must be of similar strength. The tendons will run on the spinal crest, costal facet and below the vertebral body. You need only a handful of muscles, but make them really strong. Adding too many muscles would not leave space for the arteries, and when that happens your creatures risk snapping their own necks just by turning because the muscles and excess tendons would damage blood vessels. Also incredible long tendons naturally make for good levers, see how a single skinny man can lift a car with a few pulleys. [Answer] Why not tentacles? > > Some species have been observed lifting as much as 40 times their own body weight. And larger species are famous for snapping the spines of sharks. > > > <https://oceansyrup.com/octopus-arm-wrestling/> Or why not elephant proboshi? > > An elephant's trunk has eight major muscles on either side and 150,000 muscle bundles in all. It is so strong that it can push down trees and lift a whopping 700,000 pounds. > > > [https://www.treehugger.com/extraordinary-facts-about-elephant-trunks-4858665#:~:text=It%20has%20mighty%20muscles,lift%20a%20whopping%20700%2C000%20pounds](https://www.treehugger.com/extraordinary-facts-about-elephant-trunks-4858665#:%7E:text=It%20has%20mighty%20muscles,lift%20a%20whopping%20700%2C000%20pounds). [Answer] **Ostrich** [![enter image description here](https://i.stack.imgur.com/vMo2U.jpg)](https://i.stack.imgur.com/vMo2U.jpg) Those necks are [hella bendy](https://www.youtube.com/watch?v=L0HkAIyZRn8) but how strong are they? It is hard to tell since when hunting hyaenas (its natural food source) the ostrich prefers to (1) Kick the hyaenas apart with its powerful and beautiful leg muscles. (2) Catch the hyaena by the tail and swallow it whole. In particular it doesn't use the neck to pull things apart. On the other hand I can chop up a raw lamb leg no problem using the bluntest steak-knife in my drawer, provided I saw back and forth. I'd think an ostrich neck has at least as much power as my wrist, so pulling chunks of flesh off is reasonable if the ostrich had teeth (ostriches are famously toothless) or a serrated beak. ]
[Question] [ I've got a bog-standard, handwavium-powered, handheld laser weapon of the "realistic" variety (Lightspeed "shots", a mostly invisible beam, no "pew" noise). When I pull the trigger, an intense laser beam erupts from the gun and goes where the gun is pointed. Assume there's some sort of autofocus that counteracts typical laser problems or that beam coherence isn't an issue at the ranges I'm using it at. It is designed to be deadly and is capable of killing unarmored humans. It's destructive power is roughly similar to that of a modern military infantry rifle. Questions: * What type of wound would this weapon leave in flesh? Does it vaporize the flesh? Does it flash-boil the water at the impact site? Does it give lethal sunburns? * What wavelength would be ideal (most lethal), assuming no significant engineering hurdles for uncommon wavelengths? Would a maser be better? [Answer] What type of wounds a laser weapon would leave will depend on the precise frequency, power level, and beam form (in particular, duty cycle). The exact same total absorbed power (combination of frequency and absolute power) will do very different things depending on how it is delivered. Near-IR is probably ideal for near-future anti-personnel weapons. It's what actual military lasers use. It's a relatively easy range of wavelengths to produce. The air is transparent to it, but water (and thus exposed flesh) absorbs it strongly. A low power laser will cause burns, but it will take a lot to make it lethal. You are unlikely to see more than second-degree burns over a small area, because unlike dead animals used for testing, actual enemy combatants are unlikely to stand still while you hold a beam on a single spot. A higher power continuous laser will cause severe burns immediately, possibly flash-boiling moisture on and near the surface of the skin, and you can do a lot of painful damage by sweeping the beam across the enemy. In fact, you will do *more* damage that way, because a high-power continuous-beam laser is somewhat self-defeating: once it vaporizes a tiny bit of moisture and/or surface flesh, that very vapor shields the underlying material from the full strength of the beam--you waste energy further heating and expanding a stream of already-damaged material! Moving the impact point helps mitigate that. A better mitigation, however, is to chirp the beam. If you shove the average power of the beam into a much-higher-instantaneous-power chirp followed by a gap, you can spend much less total energy on flash-vaporizing a surface layer (because you won't allow any time for heat to be conducted away from the impact point before vaporization actually occurs), with the side-effect of producing mechanical stress on the underlying material as the vapor expands; you then give just enough time for the vapor released by the initial chirp to dissipate before the next chirp arrives, eroding another layer of flesh, and causing *more* mechanical damage. With this strategy, you can rapidly drill into a surface, and then get more bang-for-your-energetic-buck by relying on the expansion of gas inside the hole to to blow the surrounding material apart, causing impact as well as thermal trauma. The goal in this case is *not* to heat the target up to a lethal temperature--in the end, what remains of the body should not have appreciably increased in temperature *at all*. Rather, the aim is to make very small amounts of the water in their body *explode*, and then dissipate, tearing chunks out of them without wasting energy on bulk heating. [Answer] This 1998 [paper](https://omlc.org/news/may98/ablation/ablchicken.html) used a continuous 90 W Nd-YAG laser on a chicken breast. They report > > In experiment 1, during the first 20 s of irradiation the tissue whitened due to coagulation but there was no ablation. At about 20 s, the surface finally began to dry and immediately a carbon layer formed. Thereafter, the absorption by the carbon layer enabled efficient laser energy deposition and ablation proceeded at a regular pace. > > > In experiment 2, a little India Ink was placed on the tissue surface to initiate energy deposition and elicit a carbon layer. The ink was immediately ablated and the ablation process proceeded based on a quasi-steady state layer of carbon created by the laser. > > > However 90 W and continuous is still a "gentle" beam. Some years ago I have been able to see the footage of a several kW pulsed laser fired on a raw chicken breast (apparently chickens are the de-facto standard for this kind of experiments). From the very beginning there was a lot of white smoke and the laser quickly pierced a hole through the breast. This [safety training](https://slideplayer.com/slide/6248349/) of Arkansas University shows the effect on a human hand of the burns caused by the partial exposure to a reflected 2 kW CO2 laser. > > [![enter image description here](https://i.stack.imgur.com/f1pO8.jpg)](https://i.stack.imgur.com/f1pO8.jpg) > > > [Answer] Assuming it's definitely weaponized, you'd have the equivalent of "pulse lasers", basically instead of a continuous beam, you have multiple pulses where the energy is dumped in a tiny duration beam, give the target a little time to "settle", then hit it again. Equivalent to 3-round burst from a rifle. The short duration means efficient use of energy, just enough to hurt the target without wasting shot on the evaporated armor or whatever target is composed of that would have ejected from the target's material vaporization. But the delay between pulses should be minimal to ensure the target doesn't move enough to affect the aimpoint. [Answer] I must tell you this. There is a **very, *very* large difference** between a laser rifle and a plasma rifle. For starters, a laser rifle is **not** what you see in Star Wars or Star Trek, that's a *plasma* rifle. A laser rifle doesn't. make. much sense. to use. against humans. You see, lasers may be hot, but they need *time* to heat up the target. Unless this laser rifle is insanely powerful, consuming tons upon tons of energy, it will not kill a human. From your question, I can see that the weapon you speak of fires a *pulse* of energy. This pulse will travel at speeds beyond your comprehension, but this beam is nothing but high-intensity light. The keyword there is **light**. Said light needs some amount of time to heat the target up enough to cause any real harm, otherwise. it'll just light up the target and cause a minor burn. Using this data, we can presume that a laser *rifle* is an impractical weapon against *humans*. However, it is more practical to use against vehicles or missiles. Like this: [![enter image description here](https://i.stack.imgur.com/rVOxR.jpg)](https://i.stack.imgur.com/rVOxR.jpg) This is the US Navy's new missile interception laser weapon. If you've seen Cars 2, then you. might recall the laser weapon the antagonists used, it superheated the fuel tank of vehicles and caused them to explode. Here's a picture: [![enter image description here](https://i.stack.imgur.com/wzItf.jpg)](https://i.stack.imgur.com/wzItf.jpg) This is a far more practical application of lasers in weaponry. Let's talk about plasma rifles. They fire a superheated bullet/ball of plasma which burns through the target, again, not as lethal as a normal gun, but better than a laser rifle. **Hope this helps!** ]
[Question] [ In the late 23rd century certain groups of mankind stared down the barrel of what may be possible in the future: cross galactic relativistic kill missile storms, gamma-ray Dyson Beams, Kugelblitz black hole weaponry and potentially even exotic matter-based weapons messing with space and time itself. Some even proposed that these weapons are the answer to the Fermi Paradox, a late and great filter. The view that any group potentially willing to use these weapons must be dealt with at any cost and as soon as possible became quite popular. After the victory over the old baseline nations in the First War Of Sol, the trans-humanist groups started the gardener initiative, a program for swift, systematic interstellar colonization. All colonists had to agree to mild brainwashing that would instill disgust towards these **exotic weapons of mass destruction**. This was meant to instill a negative bias against these kinds of weapons in all the future civilizations they would seed. Additionally, everyone signed a treaty and vowed to make every daughter civilization sign the treaty as well. The treaty states that: * no signatory shall build or use exotic weapons, however owning blueprints is fine * if an exotic weapon is used in a system, it will have 25 years to defend the incident * every system within 25 light-years will broadcast 50 years after the incident if they believe the transgressing civilization has culturally shifted to an acceptance of exotic weapons or if it was an isolated incident * if less than two-thirds of the surrounding civilizations believe that the transgressors are not guilty, everyone must commit enough resources to the purge, so that the transgressor's energy resources are matched five times over (there are official formulas for this) * exotic weapons may be utilized in the purge, which happens 25 years after the broadcast vote Since the political state of the galaxy is relevant to this, here is a brief rundown: * most civilizations are gardener descendant, thus signatories * gardener descendants are extremely diverse, however most are trans-humanist and share a common origin * the few pre-gardener interstellar colonies have been "pacified" * one later colonization wave was CORE, digital minds with an efficiency agenda, they ratified the treaty * baseline humanity was mostly wiped out during the great genocide/ pacification of last regressive strongholds/ Second War Of Sol, only the Luna Hegemony and the Callisto (later Jovian) Republic survived * the few baselines colonized very little and with very little organization and signed the treaty due to outside pressure * mankind has spread across more than 80 percent of the milky way by now * life seems to be common in the universe, but mankind seems to be alone thus far; even distant galaxies seem still uncolonized * no FTL travel or communication, the setting is pretty hard SciFi * most interstellar travel is done via boost beam at 0.7c, however more advanced drives do exist * no great interstellar empires; generally each system is its own or several polities; some macrostates exist, however, they are rarely bigger than a few systems and rather loosely organized **Will this treaty be effective at preventing mankind's galaxy from descending into a state of eternal high energy warfare until everyone is dead? If not, how else could such a situation be avoided?** Isolated incidents and the bashing of bad apples are expected, but escalation should not happen. I'm aware that this comes quite close to being opinion-based, but phrasing it otherwise; **I'm asking how to keep weapons of mass destruction out of wars in an interstellar setting.** [Answer] I see an issue. A prescription is enforceable if the sanction for not observing it is deemed realistically executable. When you prescribe > > exotic weapons may be utilized in the purge > > > You are basically stating "having exotic weapons is forbidden, and if you do, I will use my exotic weapons to punish you". This is a logical shortcircuit, because every signatory of the treaty will of course produce those weapons for the sole reason of punishing possible transgressors. Not having them will make the prescribed punishment vane. The above logic is exactly what lead to the nuclear escalation between USA and USSR: I won't use nukes to attack, but I will use them if attacked. As you might now, it didn't bring to a non proliferation. [Answer] **The edict is enforced by a mysterious group.** The Watchers date back to the late 23d century - a group which took possession of all remaining weapons and which dedicates itself to preventing their future use. The Watchers themselves are enigmatic - it is not clear where new recruits to their numbers come from, or if there are new recruits. Some Watchers are deathless transhumans augmented by technologies kin to those of the forbidden weapons. Or the Watchers are angels, or ancient aliens stirred from their sleep to prevent the destruction of space time. There are many stories, and they get better with the telling. Watchers do not intervene in the affairs of the current nations in any way. Their whereabouts are not known. Their interventions, when they come, if they come, are the stuff of legend. It is possible they are legend. Do you want to test them, O King? [![sodom and gomorrah](https://i.stack.imgur.com/2eN9B.jpg)](https://i.stack.imgur.com/2eN9B.jpg) [source](https://en.wikipedia.org/wiki/Sodom_and_Gomorrah#/media/File:John_Martin_-_Sodom_and_Gomorrah.jpg) [Answer] Adding to L.Dutch's answer. I think this situation is worse than a Cold War-esque arms race. I think you are looking at inevitable total war. You will see hegemonies form, analogous to NATO and the Warsaw Pact. Then, someone on Side A will use a banned weapon. Maybe it's an accident, maybe it's on purpose, it doesn't matter. Side B will decide it was on purpose, the other members on Side A will forgive it. Side B will try to enforce the ban, by using their own exotic weapons. Side A will then try to enforce the ban on Side B, because from their point of view, B is the aggressor. Both sides end up exchanging fire with exotic weapons. ]
[Question] [ Glossing over the technological implications of interstellar travel, what sort of human labor might still be required in a future where we are capable of setting up nigh-fully automated endeavors on faraway planets? For example, a commercial mining outpost on a faraway planet operated by mostly autonomous robots? Some number of personnel would be need to oversee the outpost of course, tweaking algorithms, trouble shooting, etc. while remotely operated robots could be used to deal with on-site problems necessitating physical intervention, it could be argued that due to the communication delay over huge interstellar distances, that even for remote control some people would be needed to stay on-planet. The idea I'm working with is a hastily fabricated quasi-city in the middle of a habitable planet where a corporate venture has dropped off about 1000 workers to oversee an army of automated machinery. The plot is somewhat self-contained, as all these people have died and all the machinery is dead -- but to understand the layouts based on the needs of these people, what sort of jobs would these people have had? Is 1000 just ludicrous? I would love some help thinking through this, even if through regrettable reverse engineering, to avoid as much handwavium as possible in the final product. [Answer] It depends on: * The value of human life/labour in your society * The travel time to/from the nearest civilisation **Offshore oil rigs require ~50-200 people** and are probably your closest comparison in the modern world: they run 24/7 crews, have multi-week shift patterns and are isolated from civilisation. The people who run them are skilled, well-paid and generally 'valuable', so relatively few jobs are routinely manual. If you had multiple sites, on a planet; it wouldn't be unreasonable to expect each site to require a similar number of workers. Oil rigs are largely automated except for the jobs that would be too expensive/difficult to automate, which is where the value of people comes in. If 'people are cheap' then it's probably not worth automating too much, why pay 10kcred for a robot if the hourly wage is only 1cred? Why bother with safety rails if you can just ship in a new batch of prisoner-workers each week when the previous ones fall in the volcano? The second consideration is distance from civilisation. Not only do you need to refresh your crews periodically and to ship replacement parts (long journey == harder to source parts == more problem solving == more people), you also need to consider what the crew will need. If travel home is not practical on a regular basis (travel >1day) then people are there semi-permanently, for months/years at a time, and they'll want something to do; a pub, gym/sports grounds, holodeck, religious temple; and people to run them. 1000 people is easily enough for a small village, so you can expect one to form if there's enough money flowing through it from miners salaries. Think gold-rush prospecting towns or starship enterprise. Side note: The oft overlooked part of rig workers jobs is not just actually drilling and running maintenance, but continuing to explore/build the rig. You don't just build a rig and then leave it static forever, there's a constant workflow of new nearby exploration, additional platforms, new well heads etc. [Answer] Look at IC factories, where as much as possible is automated since humans are simply the main source of pollution for those environments: there are still human jobs, and those are mostly related with service, maintenance and upgrade. Same jobs I expect to be present on an automated mining outpost. That amount of people sounds about right for something the size of a continental office on Earth, covering several production sites located on the same continent/large nation (e.g. USA, China or Europe). Especially in service, they would work in shifts to ensure presence 24/7, with the needed rest days between shifts. You want the site to be up and running as much as possible, any second spent on a down costs your investors a lot of money. Add to those security: you don't want any unauthorized entity to access or leave the premises without clearance. [Answer] 1. [prospectors](https://youtu.be/glzYdm7of_E?t=205) 2. [company representative](https://youtu.be/casQQhO1jkw?t=61) 3. [medical officer](https://youtu.be/bQtqq5dNCiE?t=170) 4. [harsh language masters](https://youtu.be/ZxcljnLb95M?t=61) (aka security) 5. [nuke power](https://youtu.be/qR2Z7XgZ9Yc?t=59) [specialist](https://youtu.be/nnHmUk_J6xQ?t=25) 6. transportation: [pilot](https://youtu.be/MllGbvFBP2k?t=35), [driver](https://youtu.be/0Hw6A7hK9vU?t=8), [loader - class 2 rating](https://youtu.be/YPMk-EEyOpE?t=14) 7. [comms](https://youtu.be/p6fmvXTTM1k?t=10) 8. [personal trainer (balls)](https://youtu.be/U0GNKQQPHNU?t=65) Maybe you need: 9. [bartender/shrink](https://en.wikipedia.org/wiki/Guinan_(Star_Trek)) [Answer] If the AI is sufficiently advanced I don't see why you need any humans. It could be done even if the only advancements from our current technological level are in software. Remember we've only been making software as a species for less than a hundred years. Imagine the first hundred years of written language and how far it's come since then. In a few hundred years the source code of the future will make our current source code look like scratches in dirt. Software is built in layers, and as a species we're building layer upon layer of new software, working our way up abstraction layers. In a few hundred years a program for a computer is going to look like: ``` 1. build some space ships 2. go to this star system 3. bring back hydrogen and lithium ``` And the computer itself will be sufficiently smart to do what's needed. Now, can the AI deal with unknown problems on its own? Adjust its own priorities based on new information, unanticipated by its programmers? Maybe, maybe not. Maybe you need a few humans along to make changes to the logic of the robots based on events that unfold. Now maybe you need humans to support the other humans. Maybe you need a committee of experts to make decisions, or maybe just one person could do it. But the labor will be done by the robots. Or, maybe the robots are sent out without any humans. Maybe they're just given instructions to ignore anything they don't understand, or return home immediately in certain events, like encountering alien life etc. Or maybe they're sent out with only the three lines of logic as above and the human society that sends them just treats them as disposable and builds a total fleet loss risk into it's decision of how many fleets are required to gather the needed materials. ]
[Question] [ For what reason would a civilisation experiencing an almost golden age in industry and agriculture, experiencing no catastrophic plague almost all move underwater in as such that they live entirely underwater in similar sized cities as previous. The land they exist on has not changed and is still as suitable as before so for what reason would they make the move. Edit: I would like to stress the main problem I'm having is the fact that the majority of the civilisation, although not necessarily all, need to have a reason to move underwater rather than just small groups. To bring more context for this: Our civilisation let's call them the **Maya**, have been prospering and the misery and failures that have long plagued their Empire have been weathering the storm that is the Great Technological Revolution, bringing new advancements that made farming easier, people healthier and allowed cities bigger and grander then ever before accommodating numbers of people that would of once filled the entire Empire ushering in a new golden age of development and prosperity. Yet this Empire chooses to risk it all and gamble on what could either be the extension or end of this era of progress with a disruptive mass migration to the depths of the sea. To clarify once more this question is not asking the possibility or feasibility of such a move under water, but instead that if such a feat was an option although I must stress **not an incredibly easy one**, what reasons would force a civilisation to make this change. [Answer] If as you say there is nothing "wrong" with the land and nothing is driving them into the ocean, then pretty much all answers will be pointing to something being really really "right" and more attractive and figuratively *pulling them* into the sea. The actual reasons could be a list of several possibilities depending on story needs.... **Essentially, it would relate to economics.** The sum gain of the transition to living underwater outweighs the existing benefits of living on land. It has to be easier and more desirable to move their entire civilisation underwater than it is to extract said resource (whatever it is) back onto land. So it has to be something that is long term viable and so hugely beneficial in some way to quality of life/health/power generation/life span etc (to name a few possible examples) that to live on land that is perfectly liveable on is just seen as not the best use of your lifetime. As an aside, how long this transition from land civilisation to underwater civilisation takes, would vary depending on how easy it is for the powers that be to see the long-term (and short term) benefits of the move. [Answer] * Resources that need to be mined underwater * Valuables to be found in the water * A new species found under water that enslaves / lures them (while the new species takes the land :)) [Answer] Living in the ocean could provide advantages. One being war. Since the ocean is one of the least explored places on the planet, it would be the perfect place for a civilization to hide and plan out their attacks against their enemies, and it would be very hard for said enemies to fight back, since the ocean is hard to traverse. [Answer] # Waterworld If the planet in question had low land mass compared to ocean, then they may simply have run out of land to live on relative to population size/growth. Or there may be land, but formed in small, widely separated continents which are inconvenient for trade. Creating trade outposts in the ocean because they can, could provide lucrative opportunities for those who can afford it. Eventually, trade centers become rich and a population draw on their own merits. # Alien Encounter Divers may encounter a sentient species living in the deep ocean, and wish to move closer for research and trade. Or, it could be that the continents are, for anomalous reasons, metal-poor (at least in the metals they care most about), but the oceanic crust is metal-rich. Or oil. Or valuable farming fish. Economics, as stated by all. # Expansion, Not Migration If the land is suitable for habitation, then it *does not* make sense that they will *leave* it. Rather, it only makes sense that they would *expand* away from it. All species fall into the Malthusian Trap, which says that they reproduce to the subsistence level of their habitat. Another way to say it is that all species expand to fill every ecological niche that they can, humans being no exception. If you want people to *leave* the land, then you need to have a reason they can't/won't stay. Crop failure, dust storms, earthquakes, dangerous predators, etc. are all good reasons to leave while they can. ***EDIT*** # Religion If, for some reason, the priestly caste decided that living in the ocean would be preferable, they just need a story to tell why the gods have deemed it necessary, and the appropriate inducements to sway doubters who might prefer to stay. A prophecy about a coming catastrophe on land (asteroid, fire, floods, etc.) would help. Note that a similar prediction could be made by scientists, but if it is bogus, you would need a police state to ensure that none of the honest ones spill the beans (or at least, are believed). # Megalomania If the empire is strongly authoritarian and led by an effective dictator, then you simply need a reason for said person to want to migrate. For the glory of the motherland! To prove that we can! For the glory of me!!! Because I have foreseen a glorious future under the sea! # Space Exploration If the Maya are also entering the Age of Rocketry, they may have designs on colonizing space. Building under water presents many challenges similar to building on a moon or an orbital habitat. Especially if there is a time sensitive component involved, like an anticipated mega-caldera that could bring on an extended volcanic ash winter and destroy all structures on the planet's surface. Then, building underwater would force citizens to quickly develop technology for making structures air-tight, safe, redundant, closed, etc. ]
[Question] [ Premise: Modern society discovers a magic portal that leads to a parallel universe that is almost identical to our own but the earth on the other side never had humans (or any other technology wielding civilization). People who go through the portal may travel back and forth freely but there is one restriction, they cannot bring anything with them (they have to be naked). The portal is in the Brazilian Rainforest. Question: How long would it take for a group of settlers to recreate the modern world's technology and infrastructure on the other side of the portal? Edit: Transporting removes artificial fillings and empties the stomach. The portal only transports "intrinsic" parts of your body. Limited to cells with your DNA and supporting mitochondria and stomach bacteria (and any other necessary symbiotic bacteria). Transporting animals is allowed with the same restrictions. Transporting things that aren't living creatures is not allowed. Pacemakers would not be allowed. The idea is that settlers arrive with only themselves, their health, and their knowledge, along with animals as well. The portal effectively stops all technology and non-living matter (defined as a multi-cellular organism with a nervous system) from passing through. The portal itself is magical, but the process of rebuilding itself would not be. [Answer] My answer is going to take the question to the best-case extreme. We have had lots of questions of this type on Worldbuilding before, but they usually take a form where people can only make the trip once and have to bring everything they need up front. By allowing endless trips back and forth at will we can always have plenty of experts and skilled workers in every field and plenty of help. Disallowing non-living items also puts an interesting spin on this. **TL;DR**: On the order of 1-10 years if it just pops in and enough skilled people agree to try and rush-build a new modern society there and they coordinate well. Or on the order of 1 month - 1 year if we know it's coming and can prepare and practice for it and have a colossal level of support and expertise from thousands or millions of people. **Assumptions**: * The area on the other side will have reasonably close access to all necessary resources. * Concerning only living matter passes: I'm going to bring plants, but only if they are fully mature plants still alive enough that you could plant them in the ground and they could keep growing, that should count as alive. * Any potential hold-ups such as "What is this thing? Is it dangerous? Let's study it first" have all happened and are not counted in this answer. The answer starts at "We know what's going on, let's do it now and quick." This answer will follow two different cases as I go along. **Case #1: Earth evacuation.** Maybe we find out aliens are going to invade Earth sometime soon, or whatever. We have a fire under our butts. Most of the people on Earth are willing to support the effort, and millions of people give their time and skills. **Case #2: Gameworld.** The portal was designed and created by the most advanced of the ET races we have met, and they created it as a huge game. Each time the game is started the portal shows up on the participating race's home-worlds. You have advance notice about when and where the portal will appear, and you have time to prepare. We have a line of people waiting at the portal location who know exactly what their jobs are and what they plan to do each day. As soon as the portal appears, the single-file line can rush in and everyone can hurry to their required activities. It is the largest-scale multiplayer game in the history of the universe. Everything happens as fast as it possibly can, only taking as long as it takes to physically perform the minimal amount of actions necessary for the fastest method of reaching the goal. For many of the actions in the gameworld case, imagine groups of people who have practiced working together to perform one type of task as fast as possible, like race car pit crews who can work together flawlessly to do several things to a car and have it driving away all in seconds. And they will have lots of teams making lots of everything and cutting corners and hurrying things; it's ok if most things fail or break early on - as long as we have hundreds of teams rushing the same thing a few of them should succeed. Let's get building! # Go! The first thing we need to do is set up our foundation. ## Starting with primitive tools Fortunately there are ~~crazy~~ awesome people who create primitive tools from natural resources just for fun or research who we can use as guidelines. Go check out the YouTube channel [Primitive Technology](https://www.youtube.com/channel/UCAL3JXZSzSm8AlZyD3nQdBA) if you haven't already done so. Some of what follows is also from personal experience. I consider myself to be a hobby bush-crafter, or hobby "primitive survival" practitioner. I've made stone tools, started fires with flint and steel and with friction (ie: "rubbing sticks together"), made rope from plants, fired pottery the old fashioned way, dug garden beds with a stick, and done other things you typically associate with this type of activity. ### Hand Tools As long as you have various kinds of rocks you can make some very crude stone tools useful for a few tasks in less than 1 hour. If you get experienced flint nappers in your group who find flint, you could have sharp knives and axes very soon. Also, if we are allowed to bring an animal across such as a beaver and then extract its tooth, those can make good carving tools so you could have one almost immediately, but I'll just assume you wait a day for the good flint tools. By the way, flint tools can be made sharper than iron tools, they just have other drawbacks. **Earth evacuation hand tools:** 1-2 days **Gameworld hand tools:** A few hours ### Clothing As soon as sharp tools are available make clothes out of animal hides. If you skin it and wash it you can start wearing it almost immediately. It might seem gross, but I'd rather be wearing a hide that still smells like its previous owner than to keep going naked. We'll want better clothes later, but this is sufficient for now. **Both cases:** First day ### Fire With good fire starting materials, even natural ones grabbed from the wild, the best fire starters can walk out into the wilderness, grab what they need, and have a fire on day 1 if there are some very dry materials available. It could take a few days or weeks if the materials need some processing such as drying in the sun or carving with the stone tools. **Earth evacuation:** 1 day to 1 week **Gameworld:** First day. Even if it's not dry enough, with enough muscle power from lots of people we can dry things out by friction. ### Manufacturing Very primitive manufacturing was done by shaping wood or making pottery. With the right people, you'll be chopping down wood and carving it on your very first day here. Pottery will take longer since you have to find a good clay source, shape it, dry it, then fire it. You can also create water resistant objects using only wood fire ash and water. You wet the ashes, make a thick goop out of them, and use it similar to clay. It does not even need to be fired, you just leave it out for days to dry. I just learned this yesterday from one of the newer Primitive Technology videos where the guy does it and shows that an ash-bowl filled with water still has half the water left the next day. **Earth evacuation:** Wood manufacturing will start on day 1 or 2. Clay firing will start after a few days for small items if you have fire by then, up to a few weeks for larger items that take longer for the clay to dry. **Gameworld:** Wood manufacturing first day. Clay firing can take a shortcut: with enough help we can create so many clay objects that we don't care if most of them fail to fire, just fire them after a day or two and hope 1 in 1000 works. For larger clay objects you'll probably have to wait at least a few days. Time to finished pottery obects: a day or two for small objects, a few days to a week for large ones. ### Farming Someone can start working on a garden bed immediately on day 1. Even if you want to tear up the ground (not necessary for all farming techniques) you can still do it with nothing more than a stick you pick up or break from a tree. **Both cases:** Food is available on day 1, some gardening is done and mature plants in the ground on day 1, and food is not really a problem. ### Build Time: Primitive Technology Before long you will have: * huts for shelter, a shed full of knives, axes, adzes, rope, and other simple tools. * a garden bed full of plants transplanted from Earth * whatever they want made of clay including plates, bowls, bricks, tiles, etc. * stone hearths and fireplaces **Earth evacuation:** Less than a month **Gameworld:** A week ## Metal Age They will have already started on the building blocks for more advanced technologies before they complete the "primitive" section above. Someone will already have started working on a clay furnace and forge. Someone else will already have started working on a bellows. Others have already been searching for ores. I'm just calling it the metal age since they can start on them all at the same time, even iron. And I'm going to concentrate on iron here. As soon as 1 or 2 furnaces are ready, someone will already have found at least a few rocks with ores in them. Even if it takes a few tries, there will be smelted metal in less than a month, especially if a bellows is completed in time. The first metalworking tools are sticks and stones, so the first tools made out of metal will have lots of impurities and be very crudely made, but they can function. The first iron pokers, hammers, and knives on wooden handles will be hastily made all still inside that first month. Using those tools, better tools will be made. These tools will include all of the conventional blacksmithing tools and some knives, axes, adzes, saws, horseshoes, barrel rings, wheel bindings. Yes, even horseshoes and wheel bindings: we might as well get the beasts of burden over here now if they aren't already there. Make sure you've been working on carts and carriages in the meantime. Now you have homes, gardens, metal hand tools, flocks of animals, vehicles like carriages and carts, barrels, and lots of other things. Since the heating technology is already well advanced at this point you could make glass too as long as you've acquired the materials for it. **Evacuation:** 1-2 months **Gameworld:** 1-2 weeks ## Manufacturing Age At the end of the previous section, you've already had everything needed to start making the first woodworking lathes. Most of it can be made out of wood, and the cutting edge can be as simple as a blade or a sharp point. I have done rough lathe work before by putting a stick in a drill, attaching something to the stick to spin it, and applying a knife held in my other hand to the wood. For our group, they don't have the hand drill, but they could make something very similar. The first woodworking lathes could come before you even have your iron work going since you could do it with flint cutting tools. But once you have iron tools it will be even more reliable. Now you will have lots of lathed wood objects, and as soon as a blacksmith makes an iron drill bit you can get a woodworking mill going too, so your mass manufacturing base has essentially started. What you can not do well at this time is mill or lathe iron objects, but you can use iron mill and lathe cutting tools on some other metals like copper, tin, or lead. And you'll have various other tools at this point for rolling metal, bending metal, etc.. Your metal industry is mostly limited by how much metal can be acquired. If you can get lots of it, this world will have transformed into something that looks like Earth in the 17-or-1800s. Lots of things could be mass manufactured at this point, even non-iron metal objects. At this time iron objects, including steel which is made from iron, will probably still be made on an anvil until you can make cutting tools of steel-cutting quality. **Both:** Many tool bodies can be made of wood and already crafted and waiting for their cutting edges ahead of time. So this point should be only days or weeks after the metal working starts. ## Chemistry We have all this cool manufacturing, blacksmithing, glass, etc., but to continue making this colony into something resembling modern Earth we need chemistry. We're not just now starting on the chemistry, instead the work should already have been ongoing since the beginning. Ever since we had fires, primitive chemists will have been starting to create lots of chemicals. Once there were clay vials, they can be working on lots of liquid chemicals too. Before the end of the previous section, there will already have been gasifiers, beakers, tubes, and various other tools created and we'll be at a chemistry level of technology similar to the 1800s or early 1900s, except that we'll only have relatively small quantities of the chemicals so there will be an effort to simply mass produce as much as we can before we can actually start using it to do much of interest. Two of the more useful things that might come out of this are fuel and aluminum. Fuel might come from gasified wood or from plant ethanol. Aluminum will be made using the Bayer/Hall-Heroult Processes. Aluminum is important because it has a much lower melting point than iron, it makes a fine conductor (though not as good as copper), and it can be worked on easier than steal. Also the ground is full of tons of the ingredients for aluminum. Another big one to try and push for soon would be plastics and rubbers. Then we can start making covers for wiring to get ready for our later electronics. Plastics and rubbers will also make it easier to do chemistry on gases in addition to the liquids and solids we've already been working with. With our manufacturing in full swing, aluminum available to compliment our blacksmithing steal work, and fuel from plants, we might be able to start working on some automotive prototypes, the first ones probably wood frames with the simplest engine we can make. A lot of the chemistry initial buildup will happen at the same time as the previous sections, but some will have to wait until we're manufacturing stuff. We might have some prototypes for some of these things likes automotives and wiring soon, but we would have to create a factory before we could mass produce these things. The initial versions will be crude and potentially dangerous, but they could be rushed into existence around this time. **Both:** Most of this was done concurrently with previous sections. Some will have to wait until after and will take some days to months to build up various useful chemical stocks. ## Electricity It might sound like a bit of a stretch, but it would not be unreasonable to start generating some electricity as soon as we have conductors that we can start connecting fruits and vegetables with. Most people have heard of using citrus fruits as power sources, but you can do it with other thing too such as potatoes. As long as you bring a still-live one over, so it goes through the portal successfully, you can use it as soon as you can wire them up. In some stores you can even buy kits that power things this way. My kids had a potato-powered clock kit at one time. Barring plant-power, we can start making batteries if we find the necessary materials. If you have the correct materials at hand, you can make a battery just by piling the right materials together in the right way. Both of the previous two electricity-generating methods could be done as soon as you can make the wires. As soon as we have wires and magnets we can start making electricity the way we actually do it in power plants. Once we get to this point, we can set up larger scale power generating plants. We could do this soon after arriving as long as we have magnets. To actually do much of interest with the electricity will require the manufacturing from the previous section. **Evacuation:** Some months **Gameworld:** Some weeks ## 1900s level We're already building devices to use with our electrical grid and we have manufacturing and chemistry. How long it takes to have various useful devices depends on their complexity. Some examples of things you could expect rough versions of: * electric motors/engines * lights * heaters, stoves * radios * air-tight containers * airplane prototypes (early Wright brothers level) * 1800s style "submarines" (they are not what you imagine when you say submarine) * rocket prototypes * 1800s or early 1900s style automotives * pumps (both water and air) * telegraphs and maybe telephones By this point you should *not* expect: * electronic computers, at least not useful ones yet * TVs, monitors * useful rockets **Evacuation:** Less than a year **Gameworld:** Some months We might be able to have some form of crude 8-bit electronic computer soon. It would probably be just a few of them built, they would be designed for their specific purpose, and they would be used only to help bootstrap the rest of the computer revolution. These initial ones would be slow, mouse-less, monitor-less things whose time would be very valuable until they were used to help design and create the next generation of computers. Remember, this is being assisted directly by Earth computers and engineers on the other side of the portal, we only need the ones here just to get some form of automation going and then that world's computing revolution can explode. Since we are assuming limited previous life on this planet there might be no major source of fossil fuels. That is just as well: it may speed the development along, but it's all the better that we start right out developing renewable, sustainable, cleaner energy sources. It would probably start with wind and water first, and we might be trying to make solar panels after that. **Evacuation:** I think we would see prototypes and some more functional thing we associate with 1900s level technology before the end of the second year. **Gameworld:** Gameworld is still rushing headlong getting everything done literally as fast as humanly possible. We're probably still not approaching the end of the first year yet. ## 2000s level We can get up to 1800s and some early 1900s level by cutting a lot of corners. But going that last step to having very precise machining and manufacturing of precision parts and having microscopic-scale manufacturing for computer parts is going to be one of the trickier parts. How long this would take is a hot topic of debate among some people. I feel the research is inconclusive. It certainly should not take decades though. It took decades on Earth. If we have the push for this that I described initially, we should be able to do it many times faster than it took us on Earth. After all, we already have it and understand it, we're just recreating it, and we're doing so with all experts readily available. So going from the end of the previous section to being fully 2000's style modern should take on the order of years to redo it, 1 year for Gameworlders who know exactly what to do and just do it. I would say months, but there are activities which need to be physically done, tested, possibly redone, such as physically creating computers, rockets, planes, etc.. It's not just a matter of drawing the design up in your first computer you make. ## Conclusion All of the initial setup checkpoints will take days, weeks, or months. Then to get to the level of a few hundred years ago will take months, setting up mass-production (relative to what is already there) will take months. Then progress will slow down as you approach modern Earth level and you try to make everything very precise, very large scale mass production, build up a large quantity of essential components, and recreate complicated structures like modern rockets, modern cars and planes, and modern computers, medical equipment, etc.. The entire process from day 1 to the day you could almost mistake it for Earth today would be on the rough order of... **Evacuation:** 1-10 years **Gameworld:** 1 month to 1 year This is the best case scenario for fastest time, and it is borderline crazy but might technically be possible, especially since there is advance notice and preparation, and maybe even practice runs. Now I feel like I want to start a club who actually does this type of thing. What government will let us do all this in their border? [Answer] **Brazil's tourism industry would boom.** Even with the mandatory nudity, this is perhaps the easiest settlement in history, because of the free travel to and from the new world. What you do first is you set up a city at the Earth Prime-side of the portal. That would be easy enough: an interdimensional portal would draw a lot of attention and investors hoping to profit off of it. And profit they will! You bring over survivalists, Bear Grylls and his colleagues, who have actually trained for this sort of thing. Surviving alone in the wild is hard and dangerous, but if you bring a hundred people, who can just leap back whenever they feel ill or stressed out, you would very quickly establish some sort of "base camp". I'm talking tents made out of leaves, access to fresh water, a supply of food, and rudimentary cooking vessels. Not a four-star hotel, but enough for the less trained fellows to survive for extended periods of time. This should take less than a month. Then, you bring scientists: people who know how where to find iron ore and how to smelt it, people who know how a loom works and how to construct one. Engineers to the rescue! And these people will spend some time doing scouting for the things they need, but most of their efforts will be spent writing books of what they know (assuming you cannot just bring over books). Leaving behind instructions for when they grow tired of the place. This stage is ongoing but in just another month, you should have a good start on bringing over knowledge to get others started. And then… tourism time! In our world, castles are regularly built by enthusiasts for free. People love dressing up as people from the past, and living like they did. And, the idea of a whole new world would entice many people dissatisfied with the current state of Earth, luddites and nudists alike, to travel to Brazil and brave the new final frontier. Manifest Destiny 2.0, except this time they're speaking Portuguese. People would, for very affordable prices, book a holiday to this place for a week or two. They would help bake some bricks, weave some clothes, pave some roads, craft some tools, etcetera, using the knowledge that the scientists and engineers brought over. Each individual wouldn't contribute much, but with the manpower of millions, you would have a city on both ends of the portal in just a year. Of course, the Mirror City would be a pretty crappy one: Uruk meets summer camp. But the sheer manpower would get anything done over time. They built pyramids with this level of technology and far less knowledge. I think that the level of progress would slow down once you get at a level of sophistication that a tourist would need more than a day's introduction to understand, which would slow down different technologies at different stages. But the engineers, the enthusiasts, and the survivalists, they would each set up their own goal. Who will make the first steam engine in the Mirror World? The first combustion engine? The first computer? This would be another space race, and Latin American countries would compete for those pioneering achievements the way they do with football. I think it would possibly take as much as ten years for the first computer, and only because it is a milestone people would be dying to achieve. You would have an incredibly uneven level of progress - few are going to want to be the first to invent sewage in the Mirror World - and life there would generally suck. But even when the initial enthusiasm has died down, when the tourism income is slumping and the most obvious scientific measurements have been made: then you're talking settlement. The international community would map the place and divide it into countries, so they do not have to go to war over natural resources. The place would become an Australia in the end. Used to be the hot new thing, and now there's infrastructure and a permanent population but most of it remains empty. [Answer] That's really an interesting question. Even in the TV show "naked survival", the participants were allowed to bring some things with them. In your scenario, the people will start with literally nothing. (tl;dr: If the portal won't be hidden from everybody and the other side is survivable for humans, it will take about 50-100 years to reach our technological standards and maybe another 300-600 years to have the same population count) Well let's start from the beginning. A weird wormhole-looking thing appears in the brazilian rainforest. One of the most unlikely things that might happen immediately after this event is some people shouting "Hey, let's get naked and jump into that thing". So, what might happen is, that they call the police. The police will maybe call the ABIN (the Brazilian Intelligence Agency) and they will most probably secure that unknown object. Maybe they will just build a research institute around it. They won't give normal people access to this thing. From here on, there are two main questions: How does is look (i.e. can you see through it? Does it look like a portal to a different world or just like a big iron sphere)? And what happens to the things that can't pass it? Do they just vanish? Do they not interact with the object at all? Do they explode? The research institute will invite scientists from all over the world, who will try to find out what that object is. They will try if it's safe to stick sensors into that thing. Then they will stick sensors into it. If the parts of the sensors that touch the surface of the object just vanish, the object will be considered dangerous and the scientists won't let any living creature touch that thing. On the other hand, if the sensors don't interact with the object and just appear on the backside of it, the scientists might think, that it's just some kind of hologram and maybe won't recognize it as a portal to a different dimension. It will take a few years just to build that research facility and do some research. The press will find out about that object. There will be many conversations on the internet, there will be conspiracy theories about that object. Maybe some people will try to destroy the research facility. Meanwhile in the facility, something might happen that identifies the object as a portal. Maybe the scientists watch insects that fly through the portal or an animal from the other side jumps through it and appears on our side. Now things will become a little bit harder to explain. Why can extradimensiomal animals pass the portal, but research instruments can't? The first idea of the scientists may be that the portal only works in one direction. But it won't take long until they throw a rat or some other test animal into that portal and see that it survives the journey. You could explain that with "only living biomass can pass the portal", but why are dead things like hair, fingernails, tooth enamel etc. unaffected? Why are wooden constructions excluded from traveling through that portal? Why does the water in living cells or blood pass the portal while the water in your stomach can't pass it? If the scientists can find a physical reason, why only living biomass can pass the portal and the test animals survived long enough, they might find it safe enough to let humans pass the portal. Maybe the first test persons will be death sentenced prisoners. They will be pretty surprised that they appear naked on the other side and they will be hungry, but they survive and can return to our side after a few minutes. They will have some medical examinations to see the effects on the human body that the travel and the other side made. If they can't find a reason for why this can pass but that can't pass, they might wonder if the portal is made by intelligent aliens and be too afraid to send people through it. Also, you don't know if the portal will suddenly disappear. After that, you need some survival experts that examine the new world. You need to know how dangerous the animals are, if they are edible or poisonous, which plants are edible and if there are other dangers. Maybe the other world is highly radioactive or the atmosphere is poisonous or the sun radiation is unhealthy or it is too hot/cold to live there - especially when you are naked. So the first people who go there will maybe only stay there for a few minutes. Then they will begin to build simple tools from wood and stones, they will produce some simple clothing, they will build shelters and maybe sleep a night there. They will eat some plants. If they feel sick, they can simply return to our world and anything poisonous they might have eaten, vanishes from their bellies. After the first explorers found enough food sources you need a lot of craftsmen to build wooden houses, fireplaces, better tools etc. So, in our world you have to think about how to find the right people. You need to find people who are good enough in what they do and who are willing to work for food and shelter only. In the first years there will be no money on the other side. Maybe nobody wants to work in ore mines for free, so there might be a new slave culture. The more people go to the new world, the faster technology will improve. First there will be machines that build basic survival goods, like fabric, clothes, bows and arrows, knives, pots, dishes, wooden boards for houses and furniture etc. When the first people start to build iron tools or machines, it won't take long until electricity will become available. That will make it easier to craft more machines. The people need to establish a financial system. Maybe they build a "National Portal Bank", that links to their bank accounts on our side or everybody starts with an initial amount of money. They also need some extradition agreement between the old and new world, so people from the old world can't just travel to the new world, destroy the city and jump back to the old world. Bit by bit there will be new jobs available. You will still need a lot of farmers and craftsmen, but there will also be a lot of people who copy books from the old world and who establish more and more modern technology. The progress will become faster and faster but it will depend on the willing of technology transfer between the old and new world. The big businesses from the old world can't just sell their new tech to the new world people. They have to rebuild it on the other side. The portal will become the biggest international travel hub of the world on both sides and maybe the favourite target for terrorists. So a short timeline of how I imagine the progress: 1 week: discovery of the portal and installation of a safety zone around the object 1 year: building of a research facility 1 year: research of the object without anything travelling through it, then accidental discovery of it being a portal 1 month: testing if animals survive 6 months: testing if humans survive and what influence the journey has to their bodies. Of course everybody will need a quarantine after coming back. 1 year: survival experts testing the survival conditions and digestibility of the most common plants and animals. 5 years: craftsmen building wooden houses 10 years: building of basic machines for food, clothing and woodwork 10 years: establishing an electric power supply and building simple electric machines. 10 years: finding chemical elements for medicine and semiconductors and building first simple computers. Establishing an optical data connection between the new and old world. 15 years: old world companies building facturies in the new world At this point, we might reach the technology of the old world. Kids who were born in the new world might be overwhelmed by the fast progress and maybe can't operate all the new stuff. There will be mainly one big city in the new world with a few villages around it. It will take a long time to colonize the whole new world. At least a few hundred years. Travelling between the worlds might become really expensive because the portal is too small to handle millions of travellers per day. (Also you need to buy new clothes and take a meal everytime you travel) So I think if the people of the old and new world work hand in hand, it might only need about 50 years to reach our technology level. If travelling and exchange of data is somehow prevented, it might take hundreds or thousands of years for the new world people to research the technology again. The growth of population will depend on how many people moved to the new world. Let's say a million people went through the portal and the population doubles every fifty years, then it will take 650 years to reach our world population again. [Answer] **Parasites, Bacteria, Biting Wildlife, and Apex Predators Would Make It Take A Really Long Time** I think a big question that hasn’t been brought up in the previous answers is how are these people going to deal with bacteria, parasites, and interactions with other native wildlife like large predators, venomous snakes, and stinging insects. If only living organic matter can pass through the portal that means the people coming through will have no clothes, no footwear, no camping supplies, and most important **no medicine**. Antibiotics have to be carried in containers, after all, and may not be able to pass through since they aren't living matter. When people go to the Amazon or other rainforest regions today they often wear heavy clothing to prevent mosquitoes and other insects from biting them, closed-toed footwear to prevent them from being stung or bitten by venomous snakes, fire ants, or even just cutting their foot on a rock and getting infected, and often bring special camping gear to keep out wildlife while sleeping and to purify water to drink. Mosquitoes, bullet ants, fire ants, poisonous plants, spiders, scorpions, kissing bugs (which spread Chagas disease), assassin bugs, poison dart frogs, venomous snakes, South American army ants, are all concerns without proper footwear, clothing, and bug spray. While people do live in these areas without modern conveniences, many societies do use clothing or footwear of some kind and most of them are not people used to modern life who have lived in controlled, indoor environments all their lives. And in many cases their gut bacteria have adapted to the local water microbes (this is why one of the golden rules of travel is never drink unfamiliar water wherever you go unless you have lived there a long time). Even if you only send people who are used to living without clothes or shoes and drinking river water, a world without humans could result in very different parasites and diseases in the water supply for which modern immunity means nothing. **Disease will cause massive casualty rates without access to medicine.** Viruses may not be that big of an issue because many viruses are thought to have transferred to humanity from domestic animals, and if you’re in South America the only easy source of viruses would be New World monkeys (compare Africa, where you might get viruses from apes or even non-human hominins depending on the setting). The big issue will be parasites, and in pre-urbanized societies parasites are a much larger issue than viruses. [Some examples known from South America can be found here](https://kids.frontiersin.org/article/10.3389/frym.2018.00058). The big one? Malaria, which would be worse without any anti-malarial drugs you can bring with you. There are a lot of parasites in water bodies around the world, especially in tropical climates, and others can be transmitted to humans if they eat the local wildlife (our tapeworms originally came from a species that infests lions and hyenas, for example). Parasites reduce the quality of life for the settlers, may require other individuals to care for them, and can cause disability or even death, especially in a world without anti-parasite drugs. **The Amazon is about the worst place in the world to try and settle without the aid of a pre-existing technological base**, as its high biodiversity and warm, wet climate means that parasites and stinging insects are everywhere, compared to somewhere like a grassland or desert (and it's actually been suggested this is one reason why human civilization first developed away from heavily forested areas). At least in a desert or grassland you don't have to constantly worry about parasites and disease-carrying insects. **Food is also going to be a major problem** because as per OP you can't bring dead organic matter through the portal. So all food has to be gathered on site and you likely can't gather enough in the local area to feed a large group of people without tools to increase efficiency. At the least you might strip the area bare of edible plants. Catching game is going to be difficult without tools or tools with which to build tools (scrapers, appropriate striking tools and material to make arrowheads, sinew or sap to attach arrowheads onto shafts). And while you can bring livestock through to kill for meat and leather, you will have to bring them through *alive* and have no tools with which to kill and butcher them. And when you do you have no way of keeping them from wandering off or trampling you in a panic when you try to kill them because all halters, leadropes, and reins will disappear the minute you go through the portal. It is *hard* to restrain a horse, cow, or other large livestock without a halter, because even docile livestock tend to do what they want when not restrained and given how big they are it is difficult to stop them. **Apex predators would be a huge problem**. The nature of the portal means no guns or even spears and bows and arrows to defend against attacks from jaguars and caimans. At best weaponry has to be made from scratch. If this is a world where humans never got to South America it also means *[Smilodon](https://en.wikipedia.org/wiki/Smilodon)*, [dire wolves](https://en.wikipedia.org/wiki/Dire_wolf), [short-faced bears](https://en.wikipedia.org/wiki/Arctotherium), and *[Protocyon troglodytes](https://en.wikipedia.org/wiki/Protocyon)*, all of which have been found in Amazonian Brazil and are known to eat large (read: human-sized) mammals, would still be a major issue, as these species are thought to have been wiped out by humanity (e.g., humans competing with them for food). Nothing short of a firearm or [atlatl](https://en.wikipedia.org/wiki/Spear-thrower) is going to stop them. [Exactly how common large predators are without humans to reduce their numbers by hunting them and competing with them for food is often greatly underappreciated](https://onlinelibrary.wiley.com/doi/10.1111/ele.13451) (for example, 20,000 years ago carnivorous mammals were more common on the humanless North American prairies than on the human-filled African Serengeti). People often forget that the world we live in has been massively shaped by humans even before the invention of agriculture, and that without humans the world would likely be swarming with large predators and megafauna. Without human interaction these animals would have no fear of humans and would see them as new and potentially interesting food (like polar bears in the Arctic). Something an absence of weapons would do nothing to dissuade. **How this relates to the larger question of how long it would take to rebuild modern society is that constantly having to spend time caring for sick or injured individuals or send them back through the portal for treatment, losing people who could be working due to disease, having to constantly deal with predators (or even something like a big, aggressive gomphothere or ground sloth that wanders into camp), and replacing manpower losses from predators and the associated psychological effects (think [Tsavo](https://en.wikipedia.org/wiki/Tsavo_Man-Eaters)) would slow rebuilding society to a crawl until a proper technological base is built up.** Given in this scenario people are trying to rebuild civilization in a region that [is not amenable to traditional agriculture](https://earthobservatory.nasa.gov/features/AmazonFire), has lots of parasites, few exposures of rock to mine iron and stone, lots of small biting wildlife, [extreme floods](https://www.worldwildlife.org/ecoregions/nt0128), and dangerous megafaunal predators it might take centuries. It's possible it may not ever happen or if it succeeds it succeeds due to sheer luck, sending people through the portal likely resulting in massive casualty rates. Sending people through and trying to rebuild civilization without medicine, food, tools, or means of protection sounds like either a desperation move or a particularly cruel form of execution. Even in cases like Discovery Channel's *Naked and Afraid* many of the contestants have to abandon the challenge due to injury or illness or be sent to the hospital shortly thereafter, and even those that complete the challenge are usually suffering from starvation and dehydration by the end. Humankind's biggest weakness is that without tools we are pretty much helpless or at least on the defensive until we can get tools, and we often rely on already-existing tools to make more tools. There's a reason why in most of these survival shows the goal is "get back to civilization" rather than the more ambitious "rebuild civilization". On the other hand, surviving in this world and actually trying to build this technological base could make good grist for your story. [Answer] I think it will take long. First thing first, you are naked and with an empty stomach: you need water and food, and maybe some clothes immediately afterwards. You know how to hunt, farm and sanitize water, but you have no tools. If you are lucky you can find some stone around you for concussing some animal or excavating the soil searching for edible roots, else you will be searching for fruits. You won't be able to carry any seeds, so there it goes your ability to set up farming in the short term. Congratulations, you are now a hunter-gatherer! You now how to make SiC and other fancy carbides and alloys, but you have your bare hands and nothing more. If you are lucky you will be able to light a fire before dusk, and make some sort of weapon for the next day. Yes, again that rock, or a wooden spear. Then while you wander seeking for prey you might explore to see if you find exposed ores, from which you might attempt refining some metal. You can go back and forth to eat and hydrate yourself, and use the time there only for surveying. But once you need to set up something, you will be forced to stay. ]
[Question] [ ![Buffalo Jump](https://i.stack.imgur.com/kkpYf.jpg) The Game Drive system, perhaps best exemplified by the “Buffalo Jump” of the North American Plains Indians is a hunting strategy in which large animals are chased into a preselected kill zone, such as being chased off a cliff. Animals were scared with fire, loud noise, and the simple presence of a dangerous predator (humans). Hundreds of animals could be killed this way with relatively little effort, which allowed hunters to feast for weeks at a time. There were jumps so deep that it was said that buffalo meat could be preserved for weeks at a time in the pile (still wouldn’t trust it). So that brings me to the dragon. Dragons by virtue of being a large flying predator would require very considerable amounts of meat to survive. Flight is calorically expensive, as is fighting. The dragons in my setting are more realistic, having only four limbs and weighing less than 100 kilograms. So my idea is •Dragons use fire to cut off escape routes •Because dragons fly they are immediately visible to their prey and can easily keep pace, ensuring that the hunt goes on. • Dragons don’t engage in direct combat or just incinerate their prey in the interest of energy saving. •They feast on the pile of carcasses at the base of the cliff So does the idea of a game drive system make sense for a dragon? Could it possibly explain the purpose of fire breathing and an intimidating appearance? [Answer] # Yes, but... This would be a pack hunting technique rather than for solo hunting. If you're happy to have your dragons hunt in packs then it's entirely valid. For a solo hunter it may be almost impossible to maintain more than a very short drive. Setting the fires too early may close off the path to the cliff, setting the fires too late would allow the buffalo to escape. And all of that depends on there being fuel on the ground to burn, which would need time to recover between drives. A pack would be able to maintain a path without need to set fires perfectly. A lone dragon wouldn't need that much meat anyway, smaller prey would suffice. [Answer] I do not believe that dragons would normally resort to the need for game driving. Keep in mind why humans needed to resort to game driving to get their food, we were slower than most animals so we had to resort to traps and teamwork to kill them to get food quickly (before we made weapons that allowed us to do so at range). On the other hand, traditionally dragons are much faster, stronger, can fly and have a deadly weapon that they can use at range. Given the weight of your dragons they are more akin to winged wolves (in size) that can breath fire than the traditional gargantuans they are portrayed as, so I would assume that they would a bit faster and hunt smaller prey. It would be far simpler for a dragon to fly over a herd and roast a few of them for food. (It is a far better use of their fire-breath than using it multiple times in an attempt to direct a panicking herd) They could even just divebomb the herd to pick up a few animals like most birds of prey do in the event they cant/wont use their flames. Weighing in at under 100 kgs a simple cow would last your dragon a while. For example - a male lion eats about 3.5 kgs of food per day and it normally weights about 190kgs. Your dragons gonna need far less than 3.5kgs of meat a day unless its a highly inefficient hunter, an average cow has about 300kgs of meat on it, so if your dragon hunts alone and takes down a cow it has enough meat to last it a week. ]
[Question] [ Assume that you have a Rogue Planet hurtling through deep space. Somehow, an alien civilization from, say, 1,000 ly away acquires astronomical data from this planet. This data is in the form of high resolution photographs of the sky above said Rogue Planet (presumably no clouds on an ice planet). This data is collected repeatedly, so the planet's motion may also be calculated. I imagine this will largely depend on the precise resolution of these photographs, but would it be broadly realistic for - say - a civilization 1,000 ly away to pinpoint the location of this Rogue Planet at any one point in time (say, within the area of the Moon's current rotation around the Earth)? How would precision change with the photos' resolution and the aliens' distance from the Rogue Planet? Bonus question: How would the accuracy of this method compare with the Earth straight up beaming radio signals at the aliens? (Or, at what resolution would sky photos become competitive with it). [Answer] I’ll help you understand what it means to be 1,000 ly away. First, it won’t be possible, in any way, to beam a radio signal to the planet, or to see it: * the planet is rogue, that means you don’t know where it is. And that means you don’t know where to aim your radio beam. Also, even if you were able to see where it is, you are seeing where it was 1,000 years ago. It’s not there anymore - it has moved. If you aim the radio at the spot you see the planet, you will definitely miss. But even if you hit the planet by luck, or maybe it wasn’t moving at all, you would have to wait 2,000 years before you knew. At that point, your location information is 2,000 years outdated. * The planet is 1,000 light years away. There is no telescope which could ever see a planet that far away. First, it has no sun, so it isn’t lit up. There’s nothing at all to see. But if it did have some sunlight on it somehow, there wouldn’t be enough light reaching us to make a picture at all. Even if it did have some light on it, it would be too small to see by any telescope we have or could even build. * The astronomical observations you received will be much older than 1,000 years because they got to you somehow traveling through space, or they were transmitted to you by that other civilization. Anything the planet passed by in 1,000 years may have changed its course and you would never know. Even though you are getting “repeated” updates, those updates are 1,000 years old. And even then, you did not specify how old the data was. We’re the astronomical pictures being sent in real time or were they historical pictures? In this century, Earth could not match those pictures to our star charts from 1,000 years ago to within the radius of the moon, as you say. For example, our Hubble space telescope can see objects with a resolution of 0.04 arc seconds. Let’s assume your rogue planet was a huge gas giant, 142,984 km diameter, like Jupiter. And assume it was fully lit up by something (no idea what). From 1,000 ly away it would be so small, it would occupy only 0.00000000865935221 arc seconds of your vision. This means a telescope 4.6 million times more powerful than Hubble could barely see it as a single spec. But the problem again is, it would see the speck of light coming from where the huge glowing planet was 1,000 years ago. The only way to detect this planet would be if you were lucky enough to have a star or galaxy somewhere DIRECTLY behind it, then you need a telescope millions of times more powerful than anything we have, and several years of observations, to try to calculate the planet’s approximate location by gravitational lensing. Even after you do this, your position will still be 1,000 years old. The accuracy of these methods in determining where the planet is today will be the same. No accuracy. **Bonus** Since you asked about changing the distance, that makes all the difference. If you get within 10 ly of Earth our data would be recent enough to match with theirs and you could possibly triangulate a location within slightly larger an area than the orbit of Mars. You will never get any location resolution within the size of the orbit of the moon because our own star charts don’t have that kind of resolution - even if their charts were perfect, our charts would be the weakest link. The closest star to Earth has the very best resolution - this is Proxima Centauri. Using our very best parallax measurement method, we estimate it’s distance at 268,770 Astronomical Units, within an error of +/- 5 AU. Everything else in the sky has a much larger error, so no computer is going to accurately pinpoint this planet to the resolution you want. [Answer] **In order for this to work you'd need something more than 'photographs'.** The problem you're describing is basically the same 'solve for x' trig problem that we all did ad nauseam in school. Position relative to another object is always measured in three values, and if you know any two of them you can solve for the third. In this case, the two values that you could 'know' based on observations from the surface of the Rogue planet is it's distance from visible stars, and where exactly those other stars are. In order to do that, your civilization would have to be able to identify stars visible from the Rogue planet that are ALSO visible from their own planet, and that they know the relative positions of. Identifying stars in this way requires a [spectroscopic analysis](https://en.wikipedia.org/wiki/Astronomical_spectroscopy) to measure the entire spectrum of electromagnetic radiation coming off the star. If you had this level of detail in the data gathered from the rogue planet, then you could go through a process of comparing the spectral profiles of stars visible from the Rogue planet against stars visible from your own planet until you find at least three exact matches. At that point you can take two different points in time from the Rogue planet and compare them and you'd be able to figure out the Rogue planet's relative position, velocity, and vector relative to those three stars and, by extension, your own planet. HOWEVER. **In order to know where the Rogue planet actually is now (relative to your alien civilization, you would also have to know exactly when both images were taken.** This is a non-trivial problem as there isn't a universal time ruler that you can check your images against somehow. You would have to get lucky and have the images from the Rogue planet include something you can match against observations from your own planet that has a very specific time frame. Supernovae are ideal for this because they are very bright, very unique, and only last for a short time. However, there's no guarantee that there's going to be a visible supernova at any given time for you to use. [Answer] Assuming that the photographs include the entire sky of the alien planet and includes magnified telescopic images, the civilization that receives the photographs may be able to pinpoint the location that the photographs were taken at. Thus the alien civilization might receive thousands of separate photographs to cover the entire sky of the mystery planet. If the Milky Way is visible in the sky of the alien planet, the alien planet must be within the disc of the galaxy. The disc of our Milky Way galaxy is about 100,000 light years in diameter and about 1,000 light years, or a few thousand light years, in thickness "up" or "down". If the apparent diameter of the central bulge of the galaxy is measurable from the photographs it can be compared with the actual diameter of the central bulge to deduce how far the mystery planet is from the center of the galaxy. If some of the photographs and "photographs" covering the center of the galaxy are made in the proper wavelengths of electromagnetic radiation, it may be possible to calculate the precise direction to the super giant black hole at the center of the Milky Way Galaxy. The central points of the Andromeda Galaxy, M31, and M32, an elliptical satellite of M31, should be easy to locate from most parts of the Milky Way Galaxy. And the central point of galaxy M87 in the center of the Virgo Cluster should be easy to locate. So by comparing the angles between those three or four directions it should be a simple trig problem to plot the approximate location of the mystery planet. The directions to a few globular star clusters in the Milky Way Galaxy should help narrow down the position of the mystery planet. Some globular star clusters are bright enough to be visible to the naked eye at distances of over 10,000 light years, so if the photographs of the sky are telescopic some globular clusters should be detectable and identifiable. That shoud pin down the position of the rogue planet more precisely. If the civilization that receives the photographs is as advanced in astronomy as early 21st century Earth it should have some data on the directions,distances, and absolute magnitudes of many of the stars within a few hundred light years of the rouge planet's position. So once the position of the rogue planet is narrowed down to a vaolume of space several light years on a side that is 1,000 light years away, the directions to the brightest stars in the sky of the rogue planet and their apparent magnitudes compared to other astronomical data available to the civilization receiving the photographs should be enough to calculate a much more precise position for the rogue planet. And the civilization could use infrared sensing telescopes to try to directly see the infrared radiation emitted by the rogue planet at its temperature, and thus directly locate the rogue planet. So the civilization that receives the photographs should be able to narrow down the position of where the mystery planet was when the photographs were taken. How long did it take for the photographs or the information needed to digitally construct them, take to reach the alien civilization 1,000 light years away? Were physical photographs dropped off by a slower than light ship that took 100,000 years to make the journey, or dropped off by a faster than light ship that took only a single year to make the journey? Was the data to reconstruct the photographs transmitted by radio at the speed of light taking 1,000 years, or by a faster than light "hyperwave" transmitter, or by an instantaneous Dirac transmitter? Assuming for the moment that the information took 1,000 years to arrive, the rogue planet should have an orbital velocity differing from that of the investigating civilization by approximately 10 to 1,000 kilometers per second. There are 60 seconds in a minute, 3,600 seconds in an hour, 86,400 seconds in a day, and 31,557,600 seconds in a Julian calendar year. So there would be 31,557,600,000 seconds in 1,000 Julian calendar years. At a speed of about 10 to 1,000 kilometers per second, the rogue planet would travel about 315,576,000,000 to 31,557,600,000,000 kilometers in 1,000 years. A light year is defined as 9,460,730,472,580,800 meters, or 9,460,730,472,580.8 kilometers. According to my rough calculations, in 1,000 years the rogue planet will probably move about 0.033356409 to 3.335640952 light years from its previous position. Its new position should be somewhere within a cube 0.0667 to 6.671 light years on each side, centered on its old position. Of course it is possible that the civilization receiving the photographs can deduce something about the speed and direction the rogue planet is traveling and can narrow down its current position more precisely than that. And similar calculations can be made with other assumptions about the situation. Suppose that the photographs don't come from a rogue planet but from a planet that orbits a star. In that case a similar process should be able to narrow down the approximate position of the planet. Once that is done, any information about the spectral type or the precise spectrum of the star it orbits should help the receiving civilization to identify that star by comparison with astronomical data about stars in that region of space. [Answer] I think it is possible. Just simple maths and very big computers and databases. Start by identifying a couple of stellar objects on these pictures. Then calculate at which time and place the objects would be in the *relative* positions on each image. A series of images would give the flightpath of the planet. * It would be easier if there was data on very distant pulsars. * Failing that, it would help to have spectral data. * On each individual picture, it would be difficult to tell dim, close stars from bright, distant ones. But all those can be overcome by the mass of data. [Answer] You can do that if you have a database with the exact location and brightness of stars over time. If you have this you can look at the problem backwards. From the database you can compute what the sky would look like from a particular point in space and time. From this point you have the distance to any visible star and its absolute brightness, so you compute how bright it would look as seen from that point. Now you just need a match between the picture you got and something computed from your data base. To get a unique match your picture should have a lot of stars on them and enough resolution to sort out different levels of brightness. What a human being can see on earth under ideal conditions should be good enough. If you have multiple pictures and know how much time has passed between them being taken, you can also find the movement of the planet and compute where it will be in the future. PS: in Liu Cixin's 'The three body problem' series this method of identifying a point in space from the stars visible is used. [Answer] ## Star Clusters As a few people have mentioned, a photograph, even a very high resolution one, isn't going to give the sort of detailed spectrographic or astronomic data that would be needed to definitively identify any singular star in the image. This makes it difficult to fix points to begin triangulating from. However, if there was a star cluster visible, like the Pleiades in the Earth's sky, that would be a group of stars that could be readily identified and easily positioned in relation to one another, which could be used as a reference to determine a bearing and approximate distance to the rogue planet at the time the images were taken. You definitely wouldn't get "orbit of the moon" resolution, though. Think of how little the night sky changes to our eyes over the course of the year. Yes, with good telescopes and detailed instruments you can start measuring parallax between stars, but that's across a 2AU baseline. Even a high-resolution wide-view photo isn't going to show that sort of motion. So with really well-defined and comprehensive star charts, you could might get a location within a few light years. [Answer] I understand the proposition is that we detect some alien signal without knowing anything about which direction it originates from and it appears to be picture of night skies. If the time frame is very long (hundreds of years) we can compare supernova sightings and triangulate their location from. For shorter time frames (years) there are light curves of luminous variable stars. They can be deduced from photographs if they're detailed enough. For example Betelgeuse is estimated to be 500 light years away, so if it is somewhere in the middle, we can match the dataset. There have to be such stars visible for both parties. Also the time frame must roughly match, if they see them hundreds of years before/after us, then it can't be matched as we don't have hundreds of years of observations. However, now we do have accurate 3D map of most stars in 1000 light year radius and beyond, thanks to GAIA mission. So it's easy problem for a computer, as stars don't move so much in 1000 years. ]
[Question] [ In this world, elves developed along similar lines of homo sapiens, with some major differences that allow for a small metamorphic ability. Their epidermis, the outermost layer of skin, can be shaped and molded to fit circumstances. It can change color, become thicker or skinnier as needed, made to create designs, take on textures or mimic certain marerial, etc. This eliminates the need of clothing in society, as their skin can be used to take its place. If it is cold or rainy, it can become thicker and heavier, taking a coat-like shape and allowing for warmth. If is it sunny and hot, a certain portion of skin can turn into light clothing and even make logos, similar to our company labels. Even pockets can be created as needed. These can be done simply by will, allowing for remarkable degree of flexibility that is limited only by a person' imagination. How can I design this race's biology to allow for this ability? [Answer] Fair warning: This answer is a real stretch, but if you squint hard I think it'll work for you. ## **Borrowing From Others** All of the traits from your question do exist in animals already; however, they are spread out over a few different species. Between three animals, I think we can amalgamate an Elf that suits your needs, mostly. **Puff Puff** The puffer fish is well known for its ability to expand on demand. Generally, when a puffer fish is scared, it pushes water into its stomach, which unfolds into the cavities of its body until it's a tight, round ball of spines. The skin of the fish is made up of collagen fibers, which allow for an expansion of up to 40%. Also, puffer fish are known to suck in air as well as water to the same affect. All of this is useful for us, because we want a skin structure that can expend and contract at will. Imagine a humanoid with tiny bags of collagen-constructed flesh all over its body that have biological "ducting" of some kind running to each one. At will, your Elf could inflate some or all of these little bags with air or other fluid to whatever degree you desire. I would suggest air here, for several reasons: 1) Air has insulating qualities, which might address Adrian's comment about temperature, since an Elf wrapped in pockets of air would be able to stay warm, similar to wearing a coat. 2) Moving that much blood would be very taxing, and it is not as available as air 3)Water would be heavy to carry that much around, and also less available than air. Air provides a bonus that it's feasible your Elves could float really well in water, and cushion a long fall. **Chamo** Chameleons are covered in cells called chromatophores that respond to signals from the brain and bloodstream. These cells respond by shifting color. They typically only have four colors to work with - yellow, red, blue, and brown - but, like LEDs, if you have those colors display together in different mixes you'll get other colors, like red, orange, etc. How this applies to the Elf is obvious. What is less obvious is that we have the expanding skin to deal with as well, and it wouldn't really be feasible to have the chromatophores on top of the skin that expands. Rather, it would be biologically easier for the color cells to be in the tiny spaces between sacs. You did specify that they would only generate colors when the temperature is warm, which solves the problem. When the sacs aren't inflated, you could clearly see the colors, but when they are it would be much harder if not impossible. Or you could have the chromatophores on the sacs, but this way you have the choice if you need an explanation for how they behave. **Goosebumps** Humans possess the ability to manipulate their hairs at will, make them stand up and lay down, via tiny muscles that contract at each follicle. Replace the hairs with your sacs and you have a method to control the position of those sacs relative to the skin with less hand waving than otherwise. The only downside (or upside, depending on your perspective) is that your Elves wouldn't have hair where they have sacs. This makes sense in the context that the sacs, when filled with air, provide insulation, so they don't need hair from an adaptation standpoint. **Conclusion** What I am not touching on here is process of a humanoid adapting these structures. Or the pockets. Pockets can just naturally exist without issue, like with a Kangaroo, but creating them at will means skin ripping itself apart and the closing up later, and I just can't rectify that biologically or scientifically within a useful time frame. Please enjoy these thoughts, and good luck building! [Answer] # Octopodes! Basically what you're asking for is a bipedal octopus (or cuttlefish). Octopi have almost all the requirements you want, including freeform colour changes, texture changes, significant shape changes. Adding the ability to change skin thickness is a minor detail compared to what octopuses can already do. <https://youtu.be/PmDTtkZlMwM?t=14> [How cephalopod camouflage works](https://www.nature.com/scitable/topicpage/cephalopod-camouflage-cells-and-organs-of-the-144048968/) > > Chromatophores are organs that are present in the skin of many cephalopods, such as squids, cuttlefish, and octopuses, which contain pigment sacs that become more visible as small radial muscles pull the sac open making the pigment expand under the skin. Electrical activity within a chromatophore nerve (Fig. 2, G) causes the radial muscle fibers of the chromatophore (Fig. 2, D) to pull outward toward the perimeter of the chromatophore, expanding the central pigment sack (Fig. 2, A). Early morphologic and physiologic work by Florey (1969) showed that the radial muscles widen the pigment sac with increasing frequency of the nerve electrical activity. The radial muscles are thought to be connected to each other by gap junctions (Florey, 1969) so that they ‘dilate' the chromatophore in a symmetrical fashion. The elastomeric properties of the membrane around the pigment granules -the cytoeslastic sacculus (Fig. 2, C), is thought to be responsible for contracting the chromatophore after it has opened (Florey, 1969). The chromatophores can be opened quickly because they are controlled neurally: squid, cuttlefish and octopuses can change colors within milliseconds (Hanlon, 2007). > > > [Answer] They could be covered by a layer of small symbiotic insects that protect they host. They could inflate themselves to become better insulators, change colors (i think some real insects can do that) or even glow. It's a sort of biologic nano-bot dress. [Answer] Will a weird answer satisfy you? All they need is thick hydraulic inter-vertebral disks and limb joints. When is cold outside, they simply contract to lower heights, their skin create folds, lower the area exposed to the outside and push the sub-dermal fat closer to the surface. All that's needed extra to their physiology are some valves to maintain/release the synovial fluid + enough space between their internal organs and/or not very large such organsn (this is also [[Why can an elf never become overweight?](https://worldbuilding.stackexchange.com/questions/104487/why-can-an-elf-never-become-overweight]), they need the extra space between their internal organs to allow for height reduction). I'm not sure, tho, what I described is and elf, an orc or an earthworm :) [Answer] As stated by Separatrix and Tmartin, your Elves are a lot like octupi. However, I'd like to add in another idea, hair/cilia. Your Elf could be covered in millions of tiny hairs that can move, extend, contract, and change in color and stiffness. These hairs could, with precise enough musculature, weave themselves into cloth. Now, I highly doubt this could evolve naturally, but you never really asked for something evolutionarily sound. ]
[Question] [ I am building a world where one side of the planet has normal progression of day and night whereas in the other hemisphere it is always night. At first I had no idea how this could be possible in the real world. But then I came up with this idea: The world of the story is in fact a moon, orbiting a gas giant. With the particularity that one hemisphere of the moon it's always faced to the system star. Because of this, the night is caused due the gas giant shadow. And the back hemisphere is always at night (with some light reflected from the gas giant). I have hand drawn a schema, it's not a Picasso but I hope you understand me (the drawing is not on scale). [![enter image description here](https://i.stack.imgur.com/m23tO.jpg)](https://i.stack.imgur.com/m23tO.jpg) It wasn't until I made the drawing that I realized that the night in the frontal hemisphere would be too short. The rotation time around the gas giant in a 24 hours period could be a problem too. Can this system exist? Can this system exist whit day/night periods similar to Earth? If we want prolongate the night, how could result the system? I have no problem adding other elements like rings, other moons and so. I let this to your imagination/knowledge. But less is more. Thanks for reading, waiting your answers. [Answer] Geometrically speaking, you need the moon to have its rotation synchonized with the planet's revolution around the star (thanks to David Robie for the vocabulary clearup). I believe this is possible, but highly improbable, in a story I would probably perceive it as too improbable and deux-et-machineous, unless there is some hand waving explanation involved (something happening in the past locking the moon rotation on such improbable speed). Note that the moon revolution around the planet would have a slight effect on day/night line and on the position of the sun in the sky (though I am not sure if strong enough to be observable). Also, there is the question of the harsh weather. I would guess that the "day-side" being partially shadowed by the gas giant the temperature gradients would be significantly more manageable that in the case of pure tidally locked planet, but it still does not really sound like a nice world to live on. TlDr: I am afraid that without some magic/overlooking aliens with god-like technology/something there is not much plausibility in the story. Edit: one more thing to consider: the gas giants tend to be too far from the star for the system to work as described. [Answer] A gas giant satellite will most likely be tidally locked (which kinda defeats your purpose) or will at best have, for just a few millions of years, a rotation period equal to its orbital period. I think similar (but not duplicate) questions have been asked before, and the conclusion is always that no orbital arrangement would allow for it. Let me propose a different idea: if one hemisphere has a vortex over it and a source of fine ash (say, an active volcano), the ash trapped in the atmosphere would block sunlight. This might not cover a hemisphere with surgical precision, but may get you close to what you want. [Answer] Your planet is in a close orbit around a rapidly rotating supermassive black hole. Not so close that the CMB is blue shifted into a source of permanent daylight, but close enough that gravitational lensing causes the image of the event horizon to fill most of the sky in one hemisphere. That's your permanent night. A small companion star provides a day/night cycle to the other side facing away from the black hole. [Answer] It is possible to set up such a situation, at least temporarily. Probably not long enough for life to evolve. But maybe it hopped across somehow from somewhere more stable. In the Jupiter system there are a lot of big objects a lot closer. Maybe it's easier. You will need to be thinking about relative size of the gas-giant planet and the moon's orbit around it. You need to do some actual orbit calculations to get some idea of how long the eclipse lasts. As a lowest-order estimate, you could take the relative size of the gas-giant planet and the moon's orbit. The part directly behind the gas-giant is the only part in shadow. It's more complicated than that as well. The moon is unlikely to have a perfectly circular orbit around the gas-giant. And the gas-giant is unlikely to have a perfectly circular orbit around the star. This will mean that the dark portion of the orbit is different from orbit-to-orbit in a complicated pattern. It would be some non-trivial (though possible) amount of work to predict that pattern. There's probably an app-for-that somewhere on the net. Like so: When the in-shadow part of the orbit corresponds to the part that the moon is farthest from the gas-giant, it is moving slowest, but has the smallest apparent angle for the gas-giant. When it's the closest part, it's moving faster with the largest apparent angle. You would need to work out the net effects of this, using reasonable values for the mass and orbits of the various objects. Don't forget the [Roche limit.](https://en.wikipedia.org/wiki/Roche_limit) It might be reasonable to start with the Jupiter system and see what you can put together. This [website](https://web.pa.msu.edu/people/horvatin/Astronomy_Facts/planet_pages/Jupiters_moons.htm) gives you the basic data of orbit period and radius. Also, the moon's orbit and orbit of the gas-giant are unlikely to be perfectly in the same plane. If the moon rises above or below even a little, it could easily miss the gas-giant's shadow most of the time. Maybe you miss night for 3/4 of the gas-giant's orbit period. So the moon Io has an orbit of 1.769 Earth days, and orbit radius of 422,000 km. Comparing that to Jupiter's radius of 69,911 km, the naive calculation means Io is in shadow no more than about .053 of the orbit, or about 2 and a quarter hours. (Geometry left as homework.) Moons further out would have longer periods, but smaller fraction of their orbit in shadow. So Io is probably the closest you can get. And Io is [tidally locked to Jupiter,](https://www.space.com/16419-io-facts-about-jupiters-volcanic-moon.html) so it's not your planet. [Answer] **SHORT ANSWER:** This is really difficult, but I think there might be one or two reasonably plausible natural situations, and at least one artificial situation created by an advanced civilization, where one part of a world has alternations of light and dark and another part has only eternal darkness. **LONG ANSWER:** To appreciate some of the problems with such requests, you might want to look at an attempt to design a vaguely similar situation in these two posts: <https://planetplanet.net/2018/02/02/real-life-sci-fi-world-11-kalgash-a-planet-in-permanent-daytime-from-asimovs-nightfall/>[1](https://planetplanet.net/2018/02/02/real-life-sci-fi-world-11-kalgash-a-planet-in-permanent-daytime-from-asimovs-nightfall/) and <https://planetplanet.net/2018/03/21/asimov-kalgash-take2/>[2](https://planetplanet.net/2018/03/21/asimov-kalgash-take2/) **PART ONE: A TIDALLY LOCKED PLANET** All planets and other astronomical bodies rotate at various speeds determined by various factors. So if a planet orbits around a star close enough to get enough light and heat from that star to be warm enough for life, presumably like Earth life, it will have days and nights. At any one moment half the surface of the planet will be receiving light from the star and the other half will be in shadow and dark. As the planet rotates every part of the planet's surface will alternately experience day and night. If the axis of the planet is tilted the relative length of night and day will vary with the seasons at different latitudes. But even at the poles periods of constant light or constant night must last less than half of the planet's year. So no spot on that planet can have either eternal light or eternal night. Except that the distance from the planet to the star where the planet can have the right temperature for life varies with the luminosity of the star, and the luminosities of main sequence stars vary according to their mass. And a small change in the mass of the star will cause a much larger change in the luminosity of the star. So a small mass star will be really dim compared to the Sun, and thus the habitable zone around that star will be really close to it. Any planets orbiting the habitable zone around a low mass, dim star will orbit really close to it. And thus the tidal forces on the planet from that star will be very strong and the planet will become tidally locked to the star very soon in geological time. As the planet becomes tidally locked to its star, its rotation rate will be slowed and slowed until the time it takes for the planet to make one rotation will be the same as the time it takes for the planet to orbit around the star one time. Thus one side of the planet will always face the star and will have eternal day, and the other side will always face away from the star and will have eternal night. So how do you get the side facing the star to have alternating day and night, while the other side has only eternal night? That is very tricky. **PART TWO: a TIDALLY LOCKED MOON, FIRST POSSIBLE SOLUTION** The original question asks for a moon orbiting a planet, with the moon being tidally locked to the star that the planet and moon both orbit. But calculations indicate a moon would have to be tidally locked to its planet instead of to its star. it is considered impossible for a moon to be tidally locked to its star instead of to its planet. One could try making the planet a planet sized moon orbiting a giant planet and tidally locked to the planet, and not to the star. Then the side of the moon that always faced away from the planet would have alternate day and night. The side that always face toward the planet should also have alternate day and night, except that its day should be interrupted by a long eclipse every day when the moon passes into the shadow of the giant planet. And if the giant planet has a bunch of other large moons, the moon in question might often be in eclipses caused by them. So I suppose that it is theoretically possible that someone could design a plausible configuration where at at least a small segment of the side of the moon that always faces the planet would always be in eternal darkness. **PART THREE: ECLIPSING BINARY, SECOND POSSIBLE SOLUTION** Another possibility is a planet orbiting in the habitable zone close to a dim star, and tidally locked to that star, as discussed above. Except in this case the star is a close binary, a very close binary, and the planet orbits around both of the stars. Astronomers have theorized about planets in such orbits, called P-type or circumbinary orbits, and have detected some. It is possible that two really dim stars could orbit close enough to each other that a planet in their combined habitable zone would orbit close enough to be tidally locked to the stars. Thus one side of the planet would have eternal night. So what about day and night on the side facing the two stars? The planet's orbit would probably be dragged by tidal forces to orbit the two stars in the same plane as they orbited around each other. So each of the two stars would periodically eclipse the other one as seen from the planet - they would be an eclipsing binary as seen from the planet. <https://en.wikipedia.org/wiki/Binary_star#Eclipsing_binaries>[3](https://en.wikipedia.org/wiki/Binary_star#Eclipsing_binaries) And if one of the stars is a vary dim star, or less than a star, it would contribute very little light to the planet, and when it eclipsed the bright star a sort of night would fall on the star facing side of the planet. So the dimmer object should be cool enough to emit very little visible light, and also large enough in diameter to totally block off the light of the star when eclipsing it. So the dimmer object should be a "puffy planet" or a brown dwarf. <https://en.wikipedia.org/wiki/Hot_Jupiter#Puffy_planets>[4](https://en.wikipedia.org/wiki/Hot_Jupiter#Puffy_planets) <https://en.wikipedia.org/wiki/Brown_dwarf>[5](https://en.wikipedia.org/wiki/Brown_dwarf) And I guess that various possible configurations of such a system might have eclipses on the star facing side of the planet last for about 0.1 percent of the time, or 1 percent of the time, or 10 percent of the time, etc., etc. That would not be like having equal periods of day and night, but it would be a lot different from having eternal day on that side of the planet. **PART FOUR: A ROGUE PLANET WITH AN ARTIFICIAL "SUN" SATELLITE, THIRD SOLUTION** A rogue planet is a planet in interstellar space instead of in a star system. <https://en.wikipedia.org/wiki/Rogue_planet>[6](https://en.wikipedia.org/wiki/Rogue_planet) We can expect rogue planets far from any star to be very, very, very cold. But an advanced civilization could terraform a Earth-sized rogue planet and make it habitable. There would be many possible methods to heat it to the desired temperature. One such method would be to create an imitation of the geocentric model of the solar system, with a "sun" orbiting the planet instead of the planet orbiting the "sun". The advanced civilization would build a gigantic artificial sun" satellite to orbit the planet, with countless gigantic fusion generators to power countess gigantic lamps aimed at the planet. The artificial "sun" satellite would orbit the rogue planet, creating a repeating "sunrise", day, "sunset", and night sequence over every part of the planet. But if for some reason the highly advanced civilization wants to create a world with eternal night on one side, and eternal day on the other side, they can put the artificial "sun" satellite in a synchronous orbit so it is always above one place on the planet. So one side of the planet will have eternal day and the other side of the planet will have eternal night. But if for some reason the highly advanced civilization wants to create a world with eternal night on one side, and alternating day and night on the other side, they can put the artificial "sun" satellite in a synchronous orbit so it is always above one place on the planet, and then periodically turn the artificial "sun" satellite on and off. So one side of the planet will have alternating day and night and the other side of the planet will have eternal night, as requested. [Answer] As in most physics, the answer is ***absolutely***. Consider Kepler's laws. One of which states that any sectors which taken at a point perpendicular to the plane of orbit, and have the same area, will have the same time to traverse for a single body orbit. Consider the moon, which is tidally locked to the red dwarf. The Planetary body casts a shadow like so: [![enter image description here](https://i.stack.imgur.com/siqSx.png)](https://i.stack.imgur.com/siqSx.png) So long as A1 and A2 are the same area, the day-night cycle will remain the same times from each other. The only parameter left is the orbital period. In this case you mentioned that It's earth-like, so the period would be 24 hours. This example, however, is rather unrealistic, but one can ground the premise more in reality by simply making the moon's orbit more eccentric: [![enter image description here](https://i.stack.imgur.com/6Zrwv.png)](https://i.stack.imgur.com/6Zrwv.png) The law stays the same, and so long as the areas divided by the rays A1, and A2 are equal, then the day night cycle will hold. **Note** that the planetary body in this case is comically large, and that to have such a cycle in the Goldilocks zone, that the atmosphere would need to be around 0-125% thicker to trap heat. Alternatively, you can make the orbit much smaller, but keep the proportions (eccentricity) of the orbit the same, if this is done, then the mass of the blue planetary body must increase. [Answer] It's possible. You could tell people that the moon's rotational velocity matches its revolution veolicity around the planet. That is to say, the dark hemisphere is always facing ~~the planet~~ **away from the star** and never receives light. Edit: Mori and I talked it through. They are correct in saying that you can also accomplish this by synchronizing the moon's rotational period with the planet's revolutionary period. ]
[Question] [ This was an idea generated by my sister that I thought was very interesting. I intended to make it work by strapping rollerblades on a person's legs and utilize a compressed gas/steam-powered pumping device that would be worn on the back of the character. A gas pumper would push the character forward at high speed (kind of like a rocket backpack) while the rollerblades could be used for directional control. These two are connected to each other with wires and are worn like a suit. There should be something balancing weight (or do you have suggestions?) to keep the character balanced while moving. Is it possible? If not then how can I improve it? Are there any similar alternatives? [Answer] Many issues here, all going against this: * Producing steam requires a lot of heavy machinery: you need to carry water, coal and the boiler. Are you sure you want all that weight in a backpack? How are you going to fuel the boiler on your back? * Rollerblade can be used when you have a smooth pavement to roll on. Already a cobbled road would be a nightmare, and most of the roads in 18th century were not even that fancy, with just loose ground, dusty when dry, muddy when wet, with deep carved trenches were the chariot wheels were passing. Nothing suitable for a rollerblade. * Steering: if you are going at high velocity and you want to steer, you will put a high load on your wheels unless you take a very large curving radius: I doubt that rollerblades will survive the challenge. I think you can't go any better than [Stephenson's Rocket](https://en.wikipedia.org/wiki/Stephenson%27s_Rocket). [Answer] First, you need bigger wheels. The reason carriages (17th-20th century) have such large wheels is that larger wheels "soften" bumps and irregularities in the road surface by allowing a longer travel distance to climb over the height change. Then you need to use small, powerful steam engines on the skates to drive the wheels; this gets you many times the propulsion effect over the same amount of steam used as a jet or rocket, even with air entrainment or a ducted airscrew. In order to make small steam engines powerful, you need to run your steam at high pressure, which means high temperature. Now we have the basic building blocks -- a high temperature, high pressure boiler system, with spring-assisted articulated leg struts to carry the weight of the boiler and fuel tank (it'll have to be petroleum, like kerosene; that's the only high energy density, fast/clean burning, easy stoking fuel that can operate this kind of boiler), and wheels *at least* as large as those on a 1900 vintage road bicycle (not a penny farthing, but the kind the Wright Brothers built before they switched to airplanes). In the end, it's going to look at lot more like a badly drawn horseless carriage -- but small enough to (more or less) wear instead of sitting in. [Answer] Perhaps the water runs through the wheels and uses the vibration and friction to generate the heat needed for a small amount of steam pressure. Put that in with some kind of wind sail and perhaps some skis and a hill and u got urself something to start the propulsion. # Conclusion in the end for the day steam isn't going to propel a human on a device that can be carried by a person but perhaps help the wheels spin for longer to decrease the need to propel as often [Answer] # No chance The engines did get more efficient over the course of the 18th Century, but they tended to remain two man operations, one to drive and one to shovel coal, and mostly they got bigger and heavier. We're not counting the weight of coal and water here. Engines of the period aren't condensers, you need to keep pouring water in at one end to allow for the steam coming out at the other. So if you're happy for your roller skater to have a 4 ton engine operated by two men and a trailer load of coal following along behind him then go for it, but it doesn't feel like that's in the spirit of your problem. It's not until the 19th century that you get the *relatively* compact and mobile [traction engines](https://en.wikipedia.org/wiki/Traction_engine) that are more practical on the open roads but they still weigh in the region of 4.5 tons. Stephenson's Rocket was actually a nice lightweight engine at a mere 4 tons. [Answer] The OP has not been back in the last 4 years, so here is a short answer that can be expanded if ever of interest. All the existing answers are wrong. This is entirely doable. Issues are mass & range, speed, temperature & safety, In about that order. Perhaps :-). A flash-boiler, alcohol or kerosne fired, and a burner plus a water supply will generate steam, able to generate powers in the fractional to few horsepower range, either with tiny lightweight reciprocating motors, or by steam rocket. Wheels are an issue- but sensible engineering can create wheels able to handle surfaces of the day. I'll levae that to others to fill out. A "flash boiler" will convert thermal energy to steam at low to medium pressure at acceptable mass and energy levels in this context. Hydrocarbon fuels have acceptable mass and volume energy densities. A litre of ethanol or kerosine have energy content of very roughly 10 kWh / litre or kilogram (higher for kerosene) and delivered energy as steam in the say 1-3 kWh /litre range. A "Flash Boiler" (FB) consists of a coil of pipe (usually copper) heated by an external source - here a burner, with pressurised water introduced appropriately Even at 1 kWh/litre say 5 litres of fuel will provide 5 kWh - say 1 kW for 5 hours or 5 kW for 1 hour or ... . The main limitation once safe (if not sane) operation is achieved is liable to be water capacity. Steam generation requires about a gram of water per 2 kW seconds of steam generated. So a kg of water produces about 2000 kg-seconds of steam. If a rocket is is used (see below) assuming delivered "vehicle power" in the say 1% - 20% range or 20 to 400 kg seconds per kg of water. While small model reciprocating engines are well known (see below) powers in the HP + range are able to be delivered directly by direct steam rockets. Achieving this does not require rocket science in practice, only in theory :-). A steam rocket need be neither extremely large or heavy. Being strong enough to deal with peak pressure out of the flash boiler "is a really good idea". --- Flash steam to reciprocating engines for models delivering powers in the HP range are well known: How to build flash steam generatos and related steam enines [here](https://www.vapeuretmodelesavapeur.com/vaporisationinst/yates-flash-recompilation.pdf) * Includes page 23-53 full detail for building a model aircraft engine weighing 3/4 ounce and delivering 1/4 HP to a propellor. 60 psi operating at 3500 RPM :-) . Steam generator weight not stated but probably well underone pound. That's about 200 Watt delivered, or about the power of a very low end ebike. Propellor optimisation would allow low velocity vehicle operation. * Page 34 - Hydroplane. 1 HP+ delivered to prop. 30 mph max speed. Top models achieve 120 mph+ Flash steam based model hydroplanes - 120 mph. 20cc steam engine ! [here](https://www.vapeuretmodelesavapeur.com/vaporisationinst/yates-flash-recompilation.pdf) Wikipedia - [steam rocket](https://wiki2.org/en/Steam_rocket) A HTP (Hydrogen Peroxide) rocket can deliver about 300 kg-seconds per kg of HTP using silver-catalyst screens and 85% HT P (the upper limit for silver due to screen melting). The early HTP rocket packs delivers 17 seconds of flight. A say 10 kg propellant load would deliver say 300 seconds at 10mkg thrust. Hydroghen Peroxide would have been able to be synthesisedsd and concentrated "back then". First produced 1818 - [Wikipedia](https://wiki2.org/en/Hydrogen_peroxide). 100% HTP delivers 440 kg-seconds pere kg. [Answer] As L. Dutch said, steam engines are bulky. But they already had [air compression](https://www.ecompressedair.com/library-pages/compressed-air-history.aspx) in the 18th century. Just one step forward to put the compressed air in bottles. You could use it to drive your wheels. Take care to select the right size of wheels as L.Dutch mentioned. Your whole equipment is gonna be bulky, but you might be able to carry it. You won't be able to go fast and go far, and if you fall and the [valve breaks](https://www.youtube.com/watch?v=f-xmaPSZ6GM), it's gonna rip down your legs/arms/head choose your target. In general, I would not do it. [Answer] **Aluminum powered ramjet backpack.** Because we are talking about fiction,and we want physics to be firmly in the service of awesome. Consider first Project Pluto: the nuclear powered ramjet. <https://en.wikipedia.org/wiki/Project_Pluto> The working fluid of this rocket is air. Like any other ramjet it pulls air in thru the front and shoots it out the back to provide thrust. Jet engines generate the heat by burning fuel. The nuclear ramjet generated heat with a fission reaction. Having a fission reaction strapped to your back poses some difficulties. Burning aluminum is much safer! The mechanism is the same except the core of the backpack is aluminum metal. It is started with a thermite fuse and once going, air is used as the oxidant. The oxygen is consumed to produce alumimum oxide but the nitrogen is heated up greatly and vented out the rocket nozzle in back to provide thrust. You would need to get up to speed to get air flowing past the aluminum, which you could do with a hill or by skating hard. Once flowing you could adjust thrust with a choke for the air intake. The air flowing by also keeps the backpack coolish. Really this is just a jetpack full of burning near-molten metal and you are wearing rollerblades. As one does. ]
[Question] [ The world I am creating is in a swamp that contains larger than life bugs; this includes fireflies. What I ask is, could the bioluminescence of their glow somehow be harnessed or used as a light source? More Info: * The fireflies are around the size of a human (about 5ft 5inches). * The people are more on the primitive side as they don't have the modern technology we do, and their main source of light is through fire. * They have basic metal and clay skills to make pots or handing lamps; they can also make a very basic form of glass. [Answer] (I edited this answer; instead of clay batons, now we have a "clay sheet". The reason is that sheets have a bigger surface and actually would be more practical than several batons) I think they could do it. First of all, I'm not an expert in biochemistry or anything like that. I just made some research, got some names and reactions, and assumed we have some creative license here. # About the reaction The bioluminescence in fireflies is created by the reaction of: * luciferin, a chemical present in the fireflies; * oxigen, that will react with the luciferin; * luciferase, an enzyme which acts as catalyst (and thus is not consumed by the reaction). Basically, to create light, you need to create a reaction between the oxigen and the luciferin. That won't happen by itself, and that's why luciferase is on the list: it will catalyze the reaction and make the reagents release energy, making stuff glow. # Getting your ingredients (Again, I'm nowhere close to be an expert in (bio)chemistry, so I'll use some artistic license we have in fantasy/science fiction) The source of the oxygen will be the air itself. The source of luciferin and luciferase are the fireflies. You can invent the process you want to get them, but I'll guess mashing the insects with the right materials will make the thing and conveniently "trap" the chemicals you want. An example of process could be: 1. Getting the luminescent organ from a firefly; 2. Envelop it in a convenient kind of clay that will trap the luciferin; 3. Put them inside a recipient filled with a convenient oil or liquid (so there will be no air to generate the reaction); 4. Mash your clay + luminescent organ until you're sure you have just a little luciferase in your mash; 5. Remove the mash from the oil. It may glow a little, but since you are a very dedicated person, the reaction will be brief; 6. Continue mashing the clay out of the oil until it stops glowing; In the end, we'll have an oil containing luciferase and luciferin trapped in the clay. Of course, this is only for the convenience of crafting the lamp, what comes now. # The lamp To make the lamp you want, you'll make a "sheet" of clay (not sure if it's the name of the object, but it's a rectangular flat piece of clay), that you'll put inside the lamp. Maybe it needs to dry to get firm. The lamp can be made of wood, metal, or even glass. It would be similar to a common lamp you carry around, with holders to put the sheet in. It also has two little recipients: one on the top of the lamp and one in the bottom. If you opt for a "closed" design, it needs to let in some air. The recipient on top will be filled with the oil you mashed the clay in; it will need some kind of mechanism to control the oil flow. The oil, as you may guess, contains luciferase and will flow on the clay sheet, creating the reaction. The flow mechanism lets you select how much of the sheet you want to light. The recipient at the bottom will be used to capture the oil that will flow in your lamp, since luciferase is not consumed by the reaction and could be reused. To make the lamp work, you'll have to: 1. Put a new sheet of clay inside the lamp; 2. Fill the upper recipient with oil; 3. Open the mechanism and let the oil flow along the sheet; the oil will make the luciferin in the clay react with the oxygen in the air, making it glow (open more to light a bigger surface of the sheet and get a brighter light). 4. Change the clay sheet when the reaction ends(luciferin will be consumed, so this sheets are kinda like batteries); 5. Collect the used oil to reuse it. And basically that's it. I've made some sketches, I hope it helps you to visualize the idea. [![A scheme of the lamp. First view doesn't show the side supports](https://i.stack.imgur.com/uG8OP.jpg)](https://i.stack.imgur.com/uG8OP.jpg) [![A zoom on the top of the lamp and how it works](https://i.stack.imgur.com/wukp0.jpg)](https://i.stack.imgur.com/wukp0.jpg) [Answer] ## Firefly lanterns are a thing. [Even children can do it!](https://boyslife.org/hobbies-projects/projects/4673/make-a-firefly-lantern/) > > Put any males that arrive into your lantern. At least 40 fireflies per > lantern should give you plenty of light. Release them, unharmed, the > next day. > > > [![enter image description here](https://i.stack.imgur.com/RZOem.png)](https://i.stack.imgur.com/RZOem.png) With your humans and fireflies about the same size, one firefly will give enough light for a lantern's worth. A handful around an encampment should be plenty for the night. Entice them and care for them and feed them well so they'll stay voluntarily. Your community can capture them and put them on a harness if they want, but voluntary is always nicer. [Answer] A typical North American firefly is 5 mm long and produces 0.3 lumens of light for a brief moment, ~300 msec. If the bug was scaled to a length of 5 1/2 feet, and the rest of the biology scaled proportionately, then the man-sized firefly would produce 96 lumens. This is equivalent to a 7-watt bulb or a ~1 W LED light. So it would pulse like a bright candle. I think it could be used as a navigation aid. Or lighting a shaft for miners, who are used to working in the dark due to the cost of candles. They'd move around the mine shaft by striking the stone walls with their picks to generating sparks to see for a split second. So one of your creatures would be welcome and might make the miners more productive and less prone to errors and injuries. ]
[Question] [ I've looked for an answer for this, but the only information I could find dealt with the ring itself. All I want to know is what would change on the Earth if all problems were solved and the ring were there to stay. In this particular world, the geography has changed due to a total destruction of Earth's surface, with humanity evacuating to the ring. A secondary, magical humanoid race has restored the planet to nearly its original state. What I want to know is if any biological/geographical adjustments would need to be made due to the ring's presence, and what the climate zones would be. [Answer] The effects of the ring depend on three factors: * The height of the ring above earth ($h\_{surface}$) * The width of the ring ($w$) * The direction of the ring's rotational axis The first two work together to give you the apparent width of the ring in the sky ($w\_<$): $$w\_< = w/h\_{surface}$$ They also work together with the earth's radius ($R$) to give the total surface area of the ring ($A$): $$A = w\cdot 2\pi(R + h\_{surface})$$ Thus, if we assume that the ring has the same surface area as the earth (510 million square kilometers), we get: $$A = 510\cdot 10^6 km^2$$ $$\Rightarrow w = \frac{510\cdot 10^6 km^2}{2\pi(R + h\_{surface})}$$ --- If we put the ring in low earth orbit, just $1000km$ above the equator, the equation above yields a width of $$w = \frac{510\cdot10^6km^2}{2\pi(6400km + 1000km)} = 11000km$$ The "ring" would be more like a can that's almost as high as the ball that's inside. I think, we don't need to talk about the climatic effects, the ring itself won't get much sunlight on its inner surface due to its own shadow. --- Ok, so we move the ring up a bit, say to $10000km$ above the equator: $$w = \frac{510\cdot10^6km^2}{2\pi(6400km + 10000km)} = 5000km$$ Now the earth is about 2.5 times as wide as the ring, and the ring diameter is still just about 6.5 times its width. The ring basically takes all the sunlight away from the equator, and the earth takes the better part of the sunlight away from the ring. Not a workable setup. --- So we move the ring even higher to a level, where it can easily be assembled using a space elevator: geostationary orbit. Now we get: $$w = \frac{510\cdot10^6km^2}{2\pi(6400km + 36000km)} = 2000km$$ $$w\_< = \frac{2000km}{36000km} = 0.0556 rad$$ For comparison, the apparent width of the sun is $0.0093 rad$, so the ring is about six times as wide in the sky as the sun. If the ring's axis were parallel to the axis of earth's orbit, the ring would be fully in its own shadow. Thus, I will assume that the ring's axis is parallel to earth's rotational axis. During summer and winter, the ring's shadow will entirely miss the earth by a large margin, and will wander over the globe over the course of less than two months in fall and spring. This will severely disrupt climate, because we have a stripe of the earth that is in total darkness for about a week. Within this stripe, temperatures will drop brutally. As the air cools down, it gets heavier, so we get strong, cold winds out of the shadow region. I guess, icy storms would be a better word. This will have quite a bit of destructive effects. --- You can move the ring further up, another interesting point is the hight where the apparent width of the ring matches that of the sun: $$w\_< = \frac{w}{h\_{surface}} = 0.0093 rad$$ $$\Rightarrow h\_{surface} = 107\cdot w$$ $$w = \frac{510\cdot 10^6 km^2}{2\pi(R + h\_{surface})} = \frac{510\cdot 10^6 km^2}{2\pi(R + 107w)}$$ $$\Leftrightarrow ...$$ $$\Rightarrow w = 842km$$ $$\Rightarrow h\_{surface} = 90000km$$ The radius of the ring has increase by more than a factor of two, so the speed at which the shadow will swipe over the earth in spring/fall has more than doubled. This is assuming that the ring's axis is still aligned with the earth's rotational axis. Also, we now only experience total darkness for a few hours at most, with the sun being partially occluded for a few days. The climate effects should be benign now, and they will be restricted to the time around spring/fall equinox. --- If you align the axis of the ring with the axis of earth's orbit around the sun, you get a thin, unlit stripe right where the sun is in zenith. However, the earth still rotates under this shadow: At the equinoxes, points on the equator move right across the shadow region during the day, and at the solstices the tropic circles will experience the maximum shadowing, but only around noon. I.e. shadowing follows a dayly cycle, and affects a large range of latitudes. As such, the effects are not local enough to trigger catastrophic small scale phenomena, but rather significantly reduce the sunshine across the tropics. This will definitely reduce the strengths of a) the tropic rains, including monsoon, b) the trade winds, c) cyclones (hurricanes/taifoon/whatever they are called), and d) the aridity of the deserts. The reduction of the strength of the tropical air cycle will have other effects on the global system of winds, but I'm not enough of a meteorologist to make a decent guess at those. [Answer] **Thanks to the shell theorem, and assuming your engineers did their jobs, the only effect is on how light gets to the surface** The [Shell Theorem](https://en.wikipedia.org/wiki/Shell_theorem) states that the gravity caused by a uniform mass above you (e.g., a ring or a Dyson sphere) has no impact on you, the person inside the uniform mass. Only mass "below your feet" has an impact. Think of it this way. If a straight tunnel magically existed from Earth's surface to its center, then as you descended the tunnel, only the mass still between you and the center affects you. Thus, the gravity affecting you gets less and less until it's finally zero at the center. *(Which, BTW, argues quite well for something other than a liquid or solid core at the very center. Probably a really hot plasma having fun in zero-G.)* Now, this assumes your engineers did their job designing the ring. If you read Larry Niven's *Ringworld Engineers* you'll discover (because he was famously informed about it by a bunch of MIT students in the 70s) that rings are inherently unstable. You need engines to keep the ring in place. One assumes the engineers were bright enough to place the engines and design the size of the ring such that the engines don't fry the Earth. **That leaves sunlight, direct and reflected** Therefore, the only issue is the shadow cast by the ring during the day and the reflection of light off the ring during the night. However, for this to have a significant effect (other than on romance... I can see entire jewelry commercials being inspired by this ring) the ring would be required to have an enormous width. It would need to be, at a guess, thousands of miles wide just to create a discernible line of shadow on the Earth. This all depends on its radius compared to Earth's (for a fun exercise, see [this question](https://worldbuilding.stackexchange.com/questions/121882/a-self-eclipsing-orbital-ring) that deals with this from another point of view). **Conclusion** In reality, the total effect of the ring on the Earth is negligible if not outright ignorable. It might create a cool sky effect (depending on its size), but that's it. This isn't surprising as natural planetary rings (e.g., Saturn's rings) don't have an measurable impact on the planet (that I'm aware of... Fair point, I'm not perfect). [Answer] It would slow down the rotation of the Earth. I'm assuming the ring is around a line connecting the sun and the Earth to prevent the ring from blocking light from getting to the Earths surface. The consequence of this is that the Earth would slowly start to drag the ring to rotate along with itself. The reason for this is complicated but we see it happening with our Moon. The Moon creates a swelling of water on the Earths surface directly beneath it (the tide) the spinning of the Earth, which is faster than the orbit of the moon, pulls that tide in front of the moon. The mass of water then imparts a small force causing the moon to accelerate and the Earth's spin to decelerate. (a quick internet search pulls up this if you want a reference <https://www.bbc.com/news/science-environment-12311119>). Your ring would create the same effect (this also means it would require rockets on it to prevent its spinning). This could potentially be fixed by having the ring rotate with the Earth and eat the cost of having a solar eclipse every day. [Answer] If the ring lies perpendicular the the planet's axis and of a certain width, it could cast a permanent shadow onto the earth, making photosynthesis and therefore plant life impossible under this shadow. The shadow could also cause other effects in non-permanent regions in the form of a short "artificial night", which may confuse fauna and flora, cause the temperature of the region to drop and mess with the weather (air temperature plays a role in the climate's behavior). Should the ring have enough mass, it may even affect the tides, further causing interesting effects together with the gravity of the moon. Again, if the ring is perpendicular to the planet's axis and has enough mass it may encourage higher trees or mountains due to the effects on gravity. Should the ring contain large, lens-like segments (I dunno, maybe for observation or heat harvesting or technobabble), it may also have an effect on the sunlight reaching earth (think giant lasers when it lines up with the sun). In the end, the bigger the ring, the stronger the effects. Look to the moon for inspiration. Hope this helps. [Answer] Good answers so far: Ring vertical (polar orbit) you have a short eclipse daily. Unlike Ringworld, where the ring is very far from the star, and having no other mass in the system, Moonworld is subject to tugs from the asymmetry of the Earth, solar tides on the ring, and nudges from Jupiter. So station keeping systems would need to be relatively more robust than the ones used by Ringworld. The same mechanism might be used, however: Collect the solar wind and use it for hydrogen fusion engines. You have serious transport issues between the ring and the earth. The ring has to be spun really fast to give in enough centripetal force to provide gravity. This is heavy duty delta-V. If it's at syncronous orbit distance, it needs to spin at 20 km/sec to have 1 g on the inner surface. ]
[Question] [ Triskeles are popular Celtic decorative motifs. Everyone from modern day retro-Pagans to jewelry makers to Celtic bands uses them for the cool factor. But there is a little known creature, possibly mythical, that is depicted on flags and coins from disparate island regions of Europe. Flag of Sicily: [![enter image description here](https://i.stack.imgur.com/yFmIg.png)](https://i.stack.imgur.com/yFmIg.png) Isle of Man Penny: [![enter image description here](https://i.stack.imgur.com/iowJv.png)](https://i.stack.imgur.com/iowJv.png) So naturally, this got me thinking about the Triskelion as an actual creature. And, as it turns out, in my own **[World](http://aveneca.com/cbb/viewtopic.php?f=24&t=4585#p182702)**, there is such a creature. It's not been properly studied and is not amenable to life with people. It's not cute & cuddly and is useless as a hunting beast. So no one really wants to have anything to do with the poor Triskelion. * **Here follows the best cobbled description I have of it:** A rather odd creature is the Triskelion, the three legged runner of the wild marches of Eosphora, rushing & dashing about as it does upon its three legs. Triskelions are scavengers, generally eating dead rodents, small dragonets & evets, they have been known to almost merrily tread upon and gobble nadders as well. The anatomists tell us that the Triskelion is a most confounding creature. They have no lungs or heart or brain; and are mostly composed of muscle, bone and sinews. The singular eye, they say, is held in place by many strands of fine sinews. The cavernous mouth leads to a strange cavity into which many fine hairlike fingers protrude. While Triskelions do take somewhat the appearance of Men --- they have a single eye, often beautifully coloured, a nose, a mouth with crooked teeth and lolling tongue and a single ear as well as their characteristic legs & feet --- they have no language and no apparent awareness of their surroundings as one might expect of a person. They make no tools or houses. They wander the wildlands aimlessly, mostly alone, sometimes in loose gangs of perhaps a dozen. They are generally skittish; but when riled, their terrifying speed and ability to leap & kick make them formidable opponents to all but the bravest & boldest warriors. A Triskelion may stand upon one straightened leg, which it does, seemingly to gauge a sense of it surrounds. It may hop upon its toes to gain a little height. Triskelions have been known to stand or kneel upon two legs whilst leaning upon a tree or rock, as if propping themselves up for a well earned siesta! When resting, they seem to prefer folding up their legs and resting upon their knees. [![enter image description here](https://i.stack.imgur.com/wq3yM.jpg)](https://i.stack.imgur.com/wq3yM.jpg) * **Query:** *Given the physical form of the Triskelion and what little is known of its anatomy, physiology and behaviour; how might such a creature evolve?* I'm looking especially at this creature's curious anatomy (some kind of "pouch", no apparent heart or brain, etc) and wondering how it might have come to be. One of many queries in the **[Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series)**. [Answer] This thing is an [echinoderm](https://en.wikipedia.org/wiki/Echinoderm) that has evolved to dwell on land after a few dozen millions of years. The largest starfish are around a couple feet (~66 cm) wide. It is no stretch to have some larger ones. It evolved to be a little larger because that's the best compromise between, in adult size, eating other animals and not being eaten, while being as energy efficient as its cold blooded metabolism will allow. ![Staryu](https://i.stack.imgur.com/bxtyS.jpg) ![Another Staryu](https://i.stack.imgur.com/WZX6U.jpg) Being land based gives them a reason to evolve articulations and a gait that favors using legs as they do rather than the horizontal crawling of their marine cousins. It gives them more speed and agility. It also allows for jumping and absorbing a fall's impact. They would never develop these traits in water, which is much denser and viscous than air - but on land, those traits are the difference between life and death. Echinoderms also match other parts of the description, especially: > > They have no lungs or heart or brain; and are mostly composed of muscle, bone and sinews (...) The cavernous mouth leads to a strange cavity into which many fine hairlike fingers protrude. > > > The "bones" are an adaptation of the [echinoderms' ossicles](https://en.m.wikipedia.org/wiki/Ossicle_(echinoderm)), which are calcareous structural elements. Rather than a brain it has a complex neural network spanning the legsx where decisions are made, no changes there. The hollow muscles in the legs which anatomists can't decipher are intestines. As for the mouth, this is a starfush mouth up close: ![Yes, this is the mouth, not the other end.](https://i.stack.imgur.com/YKS0p.jpg) The "hair" are really many small feet which evolved to be thinner. They pull food in and keep it there. Finally, the facial features and tongue are just for show. That creature is already as ugly as beating one's own mother without those, but they make the beast even scarier, driving would-be predators away. ]
[Question] [ I've been toying around with the idea that the Empire in my flintlock fantasy setting is trying to make sure that the money used in all its territories is the same, as the use of localized currencies has resulted in some problems, especially in terms of counterfeiting. The new currency is largely paper bills. The empire wants to phase out all the old currencies with these new bills. My question is, how much of an effect would this have on inflation? The old paper bills and coins are going to become worthless as the new currency is phased into circulation, so the actual amount of cash isn't changing by that much. You exchange your local currency for an equal value of the new currency. My thinking is that the rate of inflation would not be greatly affected, but I'm not an expert on these things, so I wanted to be sure of that. So, am I right or not? [Answer] The operation will have no effect at all on inflation if done properly, ie. **if the total amount of money does not change**. This can be achieved by : 1. replacing the old currency through exchange with the new one (but not the reverse). Usually a progressive operation over months or years. 2. set the value of former currencies to zero. The value of a money is either related to its material (gold coins have at least the value of their metal), either built by the trust you have that the emitter will be able to garantee it (a bank, a state, a guild). "material value" is hard to deal with and implies devaluating the value of the material (putting large quantities on the market for nearly free), or magically turn it to something cheap, like gold into lead (expect strong reactions from money owners). "trust value" can be managed by political means. Note that if done wrongly by simply adding new bills and coins, you will indeed inflate the money quantity and reduce its value. [Answer] You've asked a question that, technically, you could research on your own. But, to be fair, economics is a subject so complex that it's an oxymoron to describe it with a single, short word. To begin, you're dealing with something that our real world had been experimenting with for (as I recall) 100-200 years before our flintlock era. You're dealing with [fiat money](https://en.wikipedia.org/wiki/Fiat_money), meaning the money, itself, has no intrinsic value (it's not made of gold, etc.). It's only purpose is to represent value in exchange. Using fiat money has pros and cons (please remember that I'm ***simplifying something awful.*** If anyone notes my oversimplification being reasonably in error, please point it out in a comment.). Fiat money is more flexible, less costly to produce, and has the capability of allowing an economy to grow far beyond the material cost of commodity coinage or commodity-backed scrip. The cons are that it's counterfeitable, subject to value fluctuation (e.g. inflation and deflation), and must be [constantly replaced](https://www.forbes.com/sites/niallmccarthy/2014/09/12/how-many-years-do-us-banknotes-stay-in-circulation-infographic/#68934b64cf54). * The narrator of Ken Burn's *The Civil War* noted that counterfeit Confederate bills were often detected because they were so much *better* than actual production scrip. One of the biggest problems with fiat money is that it's cheap and inexpensive to produce. That was circumvented (mostly) in our modern times through the use of complex difficult-to-reproduce printing processes such as the use of [Intaglio printing](https://en.wikipedia.org/wiki/Intaglio_(printmaking)). You won't have that or any of the modern technologies in your flintlock world. Therefore, you will suffer inflation due to (at least) foreign powers trying to destablize your economy by printing fakes. You'll also have inflation by patriotic crooks who are simply looking to put bread on the gold gilt tables their families should be eating at (honestly!). * Value fluctuation is amazingly complex (people make careers out of trying to explain it). But, really really really simplistically, if I think my house is worth 10,000 dinero but it's actually only worth 5,000... and some ~~idiot~~ discerning buyer purchases it... the result is inflation. In other words, *greed* and the desire to make the most money possible will naturally cause inflation. Adding a middle-man to the selling process (oh, call them *wholesalers*) causes inflation. Passing minimum-wage laws causes inflation. Suddenly running out of Mother Emelda's Amazing Hair Tonic (which *everybody* has to have!) causes inflation. War (which usually needs Mother Emelda's Amazing Hair Tonic — MEAH — to grease axles) causes inflation. That darn local wizard who happened to figure out how to wave his stinking wand and POOF! whole cart loads of MEAH appear... that causes deflation. You get the picture. * Finally, you should not ignore the last issue: paper scrip wears out quickly by today's standards, and we know how to make durable money. It's more than just printing more (inflation!), it's *distributing* it that's the problem. Now you have a bazzillion distribution points (ok, call them "banks") and you have to get the new scrip to those points and make absolutely sure the old scrip is actually destroyed and doesn't end up lining Uncle Ted's shoes ("But I have a hole in my sole! I just wanted to keep the mud out!") as he trades the scrip. You need guards because the opportunity to steal money went up a thousand-fold. In other words, there's suddenly a whole lot of people getting paid for work that isn't actually *producing* anything... inflation! And just to make things worse, you're going to replace the scrip of multiple nations. Yes, Europe did it without a ton of inflation — but that happened *today* with a lot of high-tech communication and security. How, in your flintlock era, will you determine how much of one nation's money is actually in circulation? Guess too low and the result of the exchange is inflation. Because you can't just exchange it 1:1. Oh, that would be *awful!* What if your nation has only 1,000,000 dinero in circulation but your neighbor has 100,000,000 onyx coins in circulation? Are you going to replace them 1:1? Suddenly your neighbor is 100X more wealthy than you are? Is their GDP worth that? Do they have natural resources valued like that? I doubt it. Figuring out that the exchange needed to be 1:100 or, worse, 1:50 because they have 2X the gold mines you do (or something/anything else!)... currency exchange is non-trivial. I love it! **Conclusion** I think inflation would be an entirely believable aspect of the story. I believe the efforts to staunch inflation (if your flintlock society actually understood it) would make for good writing with excellent morals we need to hear today (like "spend what you earn"...). I think the opportunity for inflation is wonderfully complex, which I like to see in stories. And I think your flintlock society is mightily screwed... which makes the best stories of all! [Answer] This should have very little effect on inflation if done carefully. There are examples of it in the real world - for example replacement of a large group of currencies by the Euro when it was introduced in 1999. The changeover went smoothly with [no inflation or panic](https://en.wikipedia.org/wiki/History_of_the_euro#Change_of_currency). A similar thing occurs (admittedly only involving replacement of a single currency) when a nation changes its currency - for example replacement of pound/shilling/pence with dollars/cents in New Zealand in [1967](https://nzhistory.govt.nz/nz-adopts-decimal-currency). A stock-pile of Newnotes is held at each bank. A citizen can deposit 'local' currency but only withdraw NewNotes to the same value. Shops take local currency or NewNotes in transactions but only provide NewNotes as change. A time limit is set beyond which the old currency will cease to be legal-tender (that is - usable for buying and selling). There is usually a longer period of grace set during which old currency can still be swapped for new at a central bank (after the point it has ceased to be legal-tender). [Answer] It's a great question. # This happens all the time in the real world, and it has **no effect** on inflation. Some say it slightly affects the "perceived stability" of the currency/government in question. ("They're forever changing the design of the notes.") Note that flakey governments do indeed frequently change the design of the notes, there's always some new scheme. And indeed those regimes usually suffer inflation. But there's no cause and effect. If the Swiss change their note designs, it's just a design change, nobody sees it as flakeyness. --- Note - OP, it's somewhat unclear if you meant: # There are two totally different issues/questions at hand... [A] replacing the "currency design" (as happened frequently, see notes above) [B] eliminating national currencies, to replace with the national currency of a bigger, encompassing nation (examples include when the Euro was introduced, and early US federal money replacing local money) [Answer] Inflation ensues when the governing body that prints currency starts to print currency that is not backed by anything; but because people accept the currency (and may be required to accept it by law), the governing body extracts value from the economy without necessarily creating any value. If I build a bicycle and sell it, I have used my time and energy to create a value that did not exist before. If I just print money and buy things of value produced in the economy, and do not produce anything of value using them, then I am effectively taxing the economy. Of course the government CAN create something of value with the money, like funding a standing army to defend against invasion, or funding a police force to prevent crime that would otherwise happen. They can build and maintain public roads that have a utility for people and business far beyond their cost. And other utilities as well, that can take advantage of economies of scale to produce power, water, sewage handling and garbage collection much more cheaply and efficiently (and less dangerously and more healthily) than if all citizens were left to their own devices. If the benefit of these to the people is greater than the cost, a value is being created, savings are being experienced, productivity is being increased. But governments tend to do many things that create much less value than they cost, like funding far more military than would suffice for self-defense, like doing political favors for their friends by over-paying for their products, or entertaining themselves or enriching themselves. They are spending "free money", and the temptations can be boundless. This can make them parasites on their economy, and this causes inflation, by increasing the amount of currency in the society without providing any service or products that increase the net value of the society. I.e. instead of making life easier, safer and more convenient for the ruled, they are imposing a hardship on the ruled to support a "royal class" because some portion of their labor and productivity is being taken from them without providing them any corresponding benefit. ]
[Question] [ I need a mechanism/organism similar to rust and virus, that will both impair the ship's components AND will kill crew, so the only thing left are a few lucky survivors on a crippled ship. Presumably the hull is breached by a tiny comet containing the mechanism. For the component damage, maybe it just attacks wiring or some electronic components (affect only copper, silicon, semiconductors etc) or certain structural elements (affects only aluminum, carbon-fibre, rubber, etc) [Answer] I'll suggest [FOOF](https://en.wikipedia.org/wiki/Dioxygen_difluoride) and then back away very quickly. That stuff is so dangerous I don't even like to *read* about it for fear of getting burned, I don't know if it can occur in nature easily enough that a ship could get hit with it but if it did any survivors would be very lucky indeed. That is to say it does occur in nature but not very often to my knowledge. It is pretty indiscriminate though so if you want to realistically cripple non-contiguous systems with it you'd need multiple tiny point sources rather than one big one. [Answer] [Strangelets](https://worldbuilding.stackexchange.com/a/52154/21222). A strangelet is a subatomic particle that converts other subatomic particles into more strangelets. This is theoretical, but the theory has it that such a thing would grow like a katamari. From [Wikipedia](https://en.wikipedia.org/wiki/Strangelet#Dangers): > > If the strange matter hypothesis is incorrect and its surface tension is larger than the aforementioned critical value, then a larger strangelet would be more stable than a smaller one. One speculation that has resulted from the idea is that a strangelet coming into contact with a lump of ordinary matter could convert the ordinary matter to strange matter. 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.** > > > I could never find online the rate of conversion... But you could tailor it to your worldbuilding needs. Anyway, when a ship gets hit by a strangelet it is only a matter of time until it completely dissolves, and the only way to survive is to get out of the ship while you can. [Answer] Humans like to live in an oxidizing environment. Oxygen oxidizes a lot of things and released energy when it does. Humans and other aerobic life forms capitalize on this to get energy. **You want a life form that can oxidize anything oxidizable.** We have life forms on earth that can oxidize many things, including iron and just about every component of a living organism. Organisms can oxidize petrochemicals. I cannot think of anything that oxidizes metallic aluminum probably because it does not occur naturally but one could imagine a metabolism like that. Oxidation is a good platform for energy metabolism. Your organisms are alien microbes that oxidize anything not already maximally oxidized: any metal with an oxide, any carbon except CO2. They are biologically unusual enough that they do not provoke a very robust immune response from humans. They are slow but they are tenacious. In an anaerobic environment they go dormant and wait. For humans, slow oxidation would be a bad way to go. ]
[Question] [ In this society, the citizens are given a bracelet-like device that is connected to the radial artery in their dominant hand. The device monitors their health, offers advice, etc and also serves as a tracking device. It is never taken off, it is a permanent part of that person, expanding and contracting as the person grows or shrinks. An important character in this story suffered a traumatic event during which his bracelet was removed/torn off. At first, I simply believed that this wouldn't have a big effect on his health aside from blood loss and that he'd be fine afterwards. But after a bit of research, I've realized that is unrealistic. What physical/mental effects would damage to the artery cause? Could he even survive this? If the removal were more 'gentle' and systematic instead of just being violently torn off, would the effects be significantly different? Technology in this society is more advanced than our current modern technology (levitating transportation exists, cloning exists, etc). This character loses his bracelet at a young age (about 6-7 years) during a violent struggle with an adult male. The device is quite literally torn off, leaving a jagged gash up his forearm until it was torn free. The character is left like this for at least 10 to 20 minutes before he is found. [Answer] **If he does not bleed to death, worst case scenario is ischemia / gangrene of the hand. But probably not even that.** The ulnar artery and the radial artery both supply the hand. If your arteries are normal, the ulnar can supply the whole hand by itself. If there is any doubt about the ulnar artery or about the connections between radial and ulnary ateries, the Allen test assesses what each artery contributes to circulation of the hand. [![arterial anatomy of the hand](https://i.stack.imgur.com/RO40j.jpg)](https://i.stack.imgur.com/RO40j.jpg) <https://en.wikipedia.org/wiki/Allen%27s_test> > > In the modified Allen test, one hand is examined at a time:[2] > 1.The hand is elevated and the patient is asked to clench their fist for about 30 seconds. > 2.Pressure is applied over the ulnar and the radial arteries so as to occlude both of them. > 3.Still elevated, the hand is then opened. It should appear blanched (pallor may be observed at the finger nails). > 4.Ulnar pressure is released while radial pressure is maintained, and the colour should return within 5 to 15 seconds. > > > If color returns as described, Allen's test is considered to be > normal. If color fails to return, the test is considered abnormal and > it suggests that the ulnar artery supply to the hand is not > sufficient. This indicates that it may not be safe to cannulate or > needle the radial artery. > > > Procedures are done using the radial artery all the time and there can be complications if the radial artery is damaged and it is the sole supply to the hand. [Radial artery occlusion after transradial coronary catheterization](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5440258/) > > Radial artery occlusion (RAO) is, in the majority of patients, > asymptomatic. This is due to dual blood supply of the hand and the > usually rich network of collateral circulation: the radial and ulnar > arteries undergo multiple anastomoses before they are connected in the > hand by the superficial and deep palmar arches. Thus, if the radial > artery is occluded, blood supply of the hand can be maintained by the > ulnar collateral circulation and RAO is a quiescent event. However, > cases of hand ischemia after RAO have been described in the setting of > inadequate collateral circulation. Some patients may experience pain > at the site of the occlusion, paresthesias or reduced limb function. > > > For narrative purposes, your hero might survive the radial artery damage but have some lasting issue with his hand - for example a buzzing electrical feel on his thumb or a reduced grip or the like. As neuropathic pain the buzzing feeling would probably get worse at night and he can have it enter his dreams. [Answer] Given the placement of the radial artery in the wrist, I will add several thoughts: 1) ***If*** one is conscious enough to apply direct pressure, and one does so quickly enough, it's not unreasonable to survive this kind of injury; if you are briefly unconscious and so lose a fair amount of blood through radial artery bleed, it can be ***very*** challenging to stay fully conscious and keep applying direct pressure: as you weaken, and your BP drops, you become less and less well oriented to reality and concentration becomes *much* harder. (If you are a polytrauma, you may well exsanguinate without care; a tourniquet may then save your life.) 2) ***If*** this device is in the wrist, and penetrates the radial artery, and the initial device-removing injury was essentially blunt-force trauma, there will also have been massive damage to the radial nerve which enervates the hand, both sensory and motor functions - especially the thumb and lower two fingers. As a direct result, one would expect your character to end up with ongoing neuropathy (might be only years long, or their whole life) ranging from tingles and lack of sensation to significant ongoing pain, grip strength waxing and waning, sensitivity to illness / infection which can result in temporary total dysfunction of the entire hand lasting a week or more and then slowly fading, and so on. 3) It's likely given the proximity of all these elements in the human wrist that the radius bone itself will have been at the least bruised or traumatized if not broken or shattered. This will add complications to all these considerations, as the wrist will need to be immobilized / splinted for some time. 4) The *mental and emotional* aspect of this is in fact ***quite*** daunting, as one then both goes through a long and arduous recovery process with a prognosis of severely limited recovery results, (say 50%-75% grip strength at best) and then must come to terms with the complete **un** *reliability* and **un** *predictability* of that hand in the long term: your character will occasionally drop thing that they were **sure** they had a good hold of, (bad proprioception nerve responses, bad sensory responses ***and*** bad motor nerve output) fumble things etc - and that's all **after** 3-6 months of **total** incapacity of that hand (think dead fish hanging off the arm the first 3 months) whilst they *learn* to use it again as though it were a newly-grafted on piece of flesh. During the time the hand is "coming back" and they are learning to use it again, it will feel almost completely numb except for excruciating bursts of pain and "fireball" feelings racing along nerve channels as individual nerve bundles get back to functioning; moreover, as the local nerve clusters have been scrambled, that relearning is not only hard, it's deeply disturbing - just *imagine* telling your little finger to curl as you always have, and having your *ring* finger straighten instead. It's as though the whole darn thing was... rewired. Randomly. How do I *know* all this when I'm **not** a medical professional? Happened to me. Link below is to a picture of that injury, on that day, in the ER - *do **NOT** click on that link* if you've a weak stomach. [***gnarly*** picture of wound to radial area of wrist - ***don't*** click if weak stomached - really. Don't.](https://www.dropbox.com/s/6pntrifxpw2cnkx/IMG_1741-42-43_small.jpg?dl=0) [Answer] A technology that could build such a device would presumably build in a fail safe mechanism that would e.g. detect the forced disconnect and try and seal the artery in some way. It seems unlikely you'd design such a device to not be removable (by accident). So I'd expect some bleeding, but no major issue. Note that puncturing the radial artery is quite common for medical procedures. > > The device is quite literally torn off, leaving a jagged gash up his forearm until it was torn free. > > > I cannot see a reason why the device would leave such a large wound. You'd not design a device like this to be so invasive (you'd probably design it not to be invasive *at all* !). In making such a device you'd be aware of the potential of such damage. You'd make such the device was removable and replaceable. There's no rational reason to make it so heavily embedded in the arm that removing it would result in such a major injury. > > it is a permanent part of that person, expanding and contracting as the person grows or shrinks. > > > This would require a device that was adapting actively to the local conditions around it. If it can do that it can certainly detect a disconnection and safely disconnect. Disconnection of the device as a precaution would not be a life threatening issue, so as an engineer I'd design it to initiate a controlled disconnection well before a forced disconnection was likely. In such a scenario the devices would be disconnecting relatively frequently and a trip to e.g. the GP or a Health Clinic would be enough to replace it. "What happened Mr. G ? Well, I was playing football and the darn thing must have got caught on the ground when I was sliding. No problem - have that fixed in a jiffy." Events like that would be as common as muck. So I think you've created a problem that would have been foreseen and prevented by the makers. [Answer] Can the character survive? Almost certainly, the radial artery is small enough and distal enough (and thus under low enough pressure) to close with direct pressure, or a tourniquet, with relative ease at a reasonable distance up the arm, as far as the armpit in fact. Do they get to keep the hand? That's going to be entirely [Story Based](https://worldbuilding.meta.stackexchange.com/questions/3300/why-is-my-question-too-story-based-and-how-do-i-get-it-opened) as are any other after effects. Post Edit: Again story issues are paramount including but not limited to the character's level of consciousness and knowledge of anatomy etc... ]
[Question] [ I understand that there is wide range of bullet calibers. I am interested in the ones that is 50 caliber or less, and if you can be high enough in a blimp to be safe either by to far to see or to far to reach? [![enter image description here](https://i.stack.imgur.com/xVuUa.jpg)](https://i.stack.imgur.com/xVuUa.jpg) [Could a city be built out of Balloons?](https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons) [Answer] There is [a XKCD What if article about catching bullets fired upwards](https://what-if.xkcd.com/81/) (because why TF not, right?), and it says, and I quote: > > If you don't have a balloon, you could potentially make this work from a mountain peak. Mount Thor, which you may remember from question #51, features a vertical drop of 1,250 meters. According to ballistics lab Close Focus Research, this is almost exactly how high a .22 Long Rifle bullet will fly if fired directly upward (...) > > > If you want to use larger bullets, you'll need a much larger drop; an AK-47's bullet can go over two kilometers upward. > > > The article is based [on these figures](http://www.closefocusresearch.com/maximum-altitude-bullets-fired-vertically): [![The bullets breath](https://i.stack.imgur.com/1N1wz.gif)](https://i.stack.imgur.com/1N1wz.gif) So it all depends on what country you are on. If you live in a place like most urbanized regions of Canada, or Japan, where gun owners are rare and will usually be content with a pistol, you would be quite safe between 750 to 1250 meters above ground. In some other places, such as... [![America! **** yeah!](https://i.stack.imgur.com/idTBR.jpg)](https://i.stack.imgur.com/idTBR.jpg) ... You might need to go way above three thousand meters above ground to be safe. And that's counting only the most assault rifle these days. I am no gun expert but I think weapons more suited for sniping could go higher. Last but not least, guns are the least of your worries. [Larry Walters flew his lawnchair over the primary approach corridor of the Los Angeles International Airport](http://darwinawards.com/stupid/stupid1998-11.html), which could have caused the first ever midair roadkilling in history. Given the current state of the world, were someone to do something like that nowadays, they would be taken down by missiles. Those can go much higher than bullets. [Answer] While several answers have done the calculations for rifle calibre firearms, we are actually missing a lot of important information. Are the people shooting at the blimp/aerostat firing as individuals or as formed bodies of troops? are they firing standard ammunition or have they gotten access to special ammunition like tracer, armour piercing and so on? Are they firing bolt action rifles, semi automatic rifles, fully automatic rifles (like a BAR) or using rifle calibre machine guns? All these factors will change the amount of damage which the target will receive. A few disgruntled people firing rifles at a passing airship will be somewhat frightening, and there is always the chance a lucky hit will damage an engine or kill or injure a crew member, but the likelihood of that happening (absent the shooter being a sniper) is very low. Formed bodies of troops become much more dangerous. A British rifle platoon just prior to WWI was quite capable of accurately estimating distances and firing up to 10 aimed rounds a minute. This level of firepower was enough to convince the Germans that they were facing machine-gun fire during the Battle of Mons in 1914. Any target in range will receive a concentrated blast of firepower, and the likelihood of an aerostat receiving critical damage or killed and injured crew is much higher. A 30 man platoon would put 300 rounds into the target in a minute, and it is likely they could reload quickly enough to engage the target several times before it could get out of range. If we assume a window long enough for 3 engagements, the platoon put 900 rounds in the target, and the likelihood of damage to structural members, cut wires and large holes torn in the envelope is quite high. The target may stagger away and crash later, but is likely to crash due to the amount of damage. [![enter image description here](https://i.stack.imgur.com/ET4dp.jpg)](https://i.stack.imgur.com/ET4dp.jpg) *Don't be in their line of sight* We can simply keep increasing the amount of damage by changing to more modern weapons (although man portable automatic weapons like the [Chauchat](https://infogalactic.com/info/Chauchat), [Lewis Gun](https://infogalactic.com/info/Lewis_gun) and [BAR](https://infogalactic.com/info/M1918_Browning_Automatic_Rifle) were actually available in the WWI period). You will now encounter higher rates of fire, and most semi automatic and fully automatic weapons also fire from 20 to 30 round magazines as standard, although higher capacity magazines have been developed over the years as well (a semi automatic AR-15 or an automatic M-4 can be fitted with a 100 round "[C-Mag](https://infogalactic.com/info/Beta_C-Mag)"). A 30 man platoon firing M-4 automatic rifles and equipped with 10 X 30 round magazines could put *9000* rounds in the target in a matter of minutes, tearing huge holes in the envelope and causing considerable damage to the structure and crew. [![enter image description here](https://i.stack.imgur.com/HUyvu.jpg)](https://i.stack.imgur.com/HUyvu.jpg) *More firepower!* The final example would be belt fed rifle calibre machine guns. These can fire at rates from 600-1200 RPM depending on the type of gun (WWII era [MG-42](https://infogalactic.com/info/MG_42)'s had an exceptionally high firing rate). [![enter image description here](https://i.stack.imgur.com/1UTQG.jpg)](https://i.stack.imgur.com/1UTQG.jpg) *This **one man** has the firepower of an entire WWI rifle platoon* So the *amount* of fire has far more bearing on the problem than just the calibre and range of the weapon and ammunition. Weapons fired by organized formations of troops will compound the damage done to the target, and the more advanced the weapons and the greater the amount of fire which can be brought to bear, the worst off the target will be. Modern Infantry platoons have a selection of belt fed machine guns and automatic rifles, so any target in range will have a huge issue. [Answer] To make things easy, I'm going to make a few assumptions and use generalities rather than math, because I don't want to do math. You speak of household calibers, so I am going to list some very common ammunition types: .22 LR .308 Winchester 5.56mm Nato .223 Remington 7.62mm .30-06 .45 .357 .38 Special 9mm We can discount several of these because they are pistol rounds. Pistols are not long distance weapons. They rely on a balance of speed and bullet mass to do damage, followed by bullet shape and composition to do additional damage. Some I listed are also small game or varmint rounds. When you take out the Varmint .22 LR and the pistol rounds like the .45, 9mm, .357, .38 special you are left with 5 rounds that may be a threat. Actually that isn't entirely true, as the .223 Remington and the 5.56mm are almost identical, as are the .308 Winchester and the 7.62mm. we can actually lump the .30-06 in here as it is so close in size and performance. The .308 Winchester is said to have an effective range close to 1000 meters in the hands of a skilled hunter. The 5.56 mm is said to have an effective range out to 500 meters (anecdotal for both rounds) That is assuming firing at a ground based target. You are going to make us shoot UP though. That's going to reduce the range a lot. I'd say your balloons are relatively safe from ground fire even from the .308 when they reach about 500 meters up. Remember, effective range is different from how high can the round go. The round may go as high as 3000 meters, but at it's peak it's not moving fast enough to cause problems. Also, as a bullet loses speed, it may start to tumble, which increases air resistance, which slows it down faster. ]
[Question] [ Writing about Fairies, the one thing I can't pin down is there reproductive cycle. My Fairies will be actual little mammals. Not just elementals who are born out of nature. I want them to have similar developmental stages as a human baby would, but I'm wondering how their physical size would affect this. Would it take a shorter time for a foetus to come to term in a smaller body? Or would it still take a long time to develop the complex brain structure that we have? [Answer] **Model your fairies after little bats.** [![enter image description here](https://i.stack.imgur.com/jOZka.jpg)](https://i.stack.imgur.com/jOZka.jpg) Ivan Kuzmin / Shutterstock.com Depicted: a [dwarf epauletted fruit bat](http://animaldiversity.org/accounts/Micropteropus_pusillus) These little bats are 20grams and about 5 cm, like your fairies. If the mothers can carry baby bats so can your fairies. > > Micropteropus pusillus is bimodally polyestrous. It has two birth > periods per year, from March to May and from September to November. > These periods are adjusted so that lactation coincides with the rainy > season and availability of fruit. Each parturition period is followed > by a post-partum estrus and then by immediate embryonic development. > > Breeding occurs throughout much of the year but mostly in March, > April, May, and November. The gestation period is five or six months. > Weaning takes from 7 to 13 weeks. (Jones, 1972; Nowak, 1999; Thomas > and Marshall, 1984) > > > Baby bats grow up fast. It is an open question as to whether intelligence requires prolonged childhood. Octopi are smart and they have no childhood. Rats and crows are smart and their mothers care for them - they are grown in about 3 months. Larger bodies take longer so your fairies will be done growing faster because they are small. I suspect sociality is what really takes a long time (for elephants, humans, dolphins) and so you can make your fairy childhood arbitrarily long for that aspect - but probably the juvenile fairies are not being carried by their mothers the whole time. [Answer] All right, we can handwave headsize and time for developing the complex brain, as these fairies are too small to have our exact style of brain. At that size unless they have a hive mind there is no realistic way they're intelligent. So a wizard/evolution did it somehow. The closest animal to their size I could find is the [Etruscan Shrew](https://en.m.wikipedia.org/wiki/Etruscan_shrew), which is between 3 and 5.2cm. There reproduction goes as such. > > The gestation period is 27–28 days, and they have 2–6 cubs per > litter.[2][9] Cubs are born naked and blind, weighing only 0.2 g > (0.0071 oz). After their eyes open at 14 to 16 days old, they mature > quickly. The mother usually moves the young when they are 9 to 10 days > old and if disturbed leads them by caravanning them to a new location. > The young Etruscan shrews are weaned at 20 days old. By three to four > weeks of age, the young are independent and are soon sexually mature > > > To give the fetus more chance to grow, have only one or two babies at a time, and keeping it at about 30 days would work best. We are already handwaving brains, so long term gestation isn't necessary. This would also explain why fairies never seem pregnant, it's over so quick it's not noticed. Instead of a mating season like most animals, they are fertile year round, which is necessary to keep their numbers up. Being so small, they are at the bottom of the food chain. Relatively quick pregnancies, followed by three or four months of raising the baby to advanced toddler hood followed by another pregnancy would be seen as a good thing. If it takes two years before the baby fairy is a toddler and the mother gets pregnant again, the fairy race will go extinct. Considering the incredible metabolism of these fairies they'll lose the baby weight in a matter of days. Shrews can starve to death if they don't eat nearly their body weight in food each day. This is another reason fairies never seem pregnant and are never fat. So rapid pregnancy, fast growth of the babies, followed by pregnancy again. They'll need a high protein and carbs diet, and we are looking at two or three pregnancies a year. Sexual maturity in females would be pretty quick, starting at most a few years old. ]
[Question] [ This is a sequel to my previous question [How big could a moon be before its orbit became too unstable or tidally locked to its planet](https://worldbuilding.stackexchange.com/q/93700/42857) OK, let's imagine that the thing everyone thought was a moon was actually a *twin* planet sharing a barycentre with BlinketyBlink. They are currently **not** tidally locked, the twin is slightly smaller, with a similar basic composition and a Venus-like atmosphere. They are far apart enough to not cause deadly disturbances on BlinketyBlink's geophysical conditions (weather, plate tectonics, volcanism, tidal waves...) Everything is just perfect and life goes on normally on BlinketyBlink. My question is : could *the twins* have an Earth-like orbit around their Sun? That's to say about 365 days, slightly elliptic and that would maintain regular weather patterns (summer to winter seasonal periods) on BlinketyBlink? My imagination gives me this [![Solar system with respective Goldilocks region ](https://i.stack.imgur.com/M92Vm.png)](https://i.stack.imgur.com/M92Vm.png) [Answer] Short answer is"yes", living on Blinketey blink would be very much like living on earth with two key differences. "Moon light" would be several times brighter. Our moon is actually about the same reflective index as coal, but the atmosphere of the second member of the binary will be much more reflective, and the apparent size will be quite a lot bigger. Tides will also be stronger. [Answer] In the situation you describe the center of mass of the system will orbit around the central star following the usual ellipse. Both planets will "dance" around their center of mass, with the result that they will get more close or more far from the star with this dance. Since you state they are far enough to not disturb each other too much, this means the change in distance from the star can be significant. [Answer] It's all a matter of the size of the sun and the distance of the orbit from the sun. How big do you want your planet to be? Our seasons are dependent on the tilt of the earth's spin in relation to the orbit around the sun. Each planet could have a different tilt. This is completely variable. The axis of spin of one planet could even be on the plane of rotation around the sun. It is also variable as to how the planets orbit each other. Perpendicular to the sun-planet line? On the same plane as the orbit around the sun? Or somewhere in between. If on the same plane, the eclipses would be spectacular, and on every orbit of one planet around the other. If it was completely perpendicular, there would never be an eclipse. [Answer] Actually, thinking about it some more, I'm not so sure that a two-body co-orbit that's perpendicular to the solar orbit would be a stable situation. At the two points in their solar orbit where A and B are equidistant from their sun the sun would be pulling on both of them equally (or almost, depending on their size differential) but at the other two points, 90° away, one would be closest to the sun while the other would be furthest away. It seems to me that this would introduce variability into their orbits, making this arrangement unstable. The reason this doesn't happen with the Earth-Moon system is because the Moon's orbit is (pretty much) aligned with the Earth's orbit. But, then again, I'm not an expert. Would anyone out there with an astrophysics degree care to chime in? ]
[Question] [ The [*Nachtkrapp*](https://en.wikipedia.org/wiki/Nachtkrapp) is a german version of the [bogeyman](https://en.wikipedia.org/wiki/Bogeyman) or in a more general term a kind of [bugbear](https://en.wikipedia.org/wiki/Bugbear). *Nacht* is the german word for *night* and *Krapp* is used in southern germany and austria as a word for *raven*. There are many different versions of this tale. Most of the time it was used to make children go to bed by stating that the *night raven* will abduct them when they are outside past their bedtime. But I am especially interested in a norse version of the *night raven*, for which I am trying to think of ways to explain how they could evolve naturally: * the *night raven* is hunting for prey at night * it doesn't have eyes and if one were to look at the empty eye-sockets he would die * it has holes in its wings that cause illness and disease when someone looks at them * the prey can be up to the size of a little human child which it will be, according to the [Wikipedia article](https://en.wikipedia.org/wiki/Nachtkrapp), > > messily devour [...], first ripping off their limbs and then picking out their heart > > > According to the [german wikipedia article](https://de.wikipedia.org/wiki/Nachtkrabb) *Krapp* can also be used as a general term for birds belonging to the raven family, or [Corvidae](https://en.wikipedia.org/wiki/Corvidae), but it might also just refer to the *raven black color*, similar to the word [*Rappe*](https://de.wikipedia.org/wiki/Rappe), which is a black horse. The *night raven* might also refer to other birds, such as owls or night herons. I was trying to think of ways to realistically create such a creature in my world. The criteria are listed above and I am trying to come as close to it as possible. This means that for example the part about messily devouring children and ripping off their limbs can safely be ignored for normal sized ravens or owls. The legend sometimes states that the raven is indeed a giant raven, but I want to avoid discussions about the Square-Cube-Law, so we will go without something roughly the size of a normal raven. I was thinking about basing it off the [Medusa](https://worldbuilding.stackexchange.com/q/34221/28789) and going with a similar approach to [this great answer](https://worldbuilding.stackexchange.com/a/34292/28789), but in the case of the Medusa answer the hair is spitting a venom at the prey, which leads to a slow death instead of looking in the eyes of the creature. *Turning into stone* also doesn't seem to fit the traditional idea of a general harbinger of death and disease. To make sure that this question is not viewed as a duplicate to the linked question I will postulate the following that I am trying to achieve in addition to the criteria listed above: * the death cannot be based on turning the prey to stone * the creature cannot have other creatures in place of the holes and empty eye-sockets that would assist in killing the prey * looking into the eye-sockets should be deadly for the prey * looking at the holes in the wings should only cause an illness or disease; nothing necessarily deadly How close can I realistically get to my harbinger of death, the *Nachtkrapp*? A list of all the questions from the series *Anatomically Correct* can be found [here](https://worldbuilding.meta.stackexchange.com/a/4109/28789). [Answer] Like the majority of harbingers of death, the dreaded *Nachtkrapp* doesn't foretell or supernaturally portend a death. Most especially when it is disease or death caused by plague or illness. The *nachtkrapp* could have supersenstive senses that enable it to detect those who are afflicted by illness or plague, but who have yet to express the symptoms of their disease. The fact that persons who see the *nachtkrapp* and succumb to illness this will be naturally enough interpreted as being caused by the bogeyman bird when, in fact, it's not. Errors in causation are often responsible for imputations of supernatural agency when none exists. The querent has established that the *nachtkrapp* is a giant creature. This explains its ability to rend the limbs of children and take them as prey. Anyone familiar with biology would be concerned about a giant bird can get about at night with empty eye-sockets. The answer is simplicity itself. The apparent eye-sockets are sources of powerful ultrasound. This obviates the need for eyes of the conventional kind. What might pass for eyes in any other species of bird is replaced by membranes capable of generating high-intensity ultrasound. These would be part of the *nachtkrapp*'s nasal passages, powered by powerful blasts of air, which a giant bird should be capable thereof, and not ocular cavities where eyes would be located. It is by looking into the sightless eye-sockets of *nachtkrapp* and being exposed to its intense and lethal ultrasonic "gaze" that brings death. While medical ultrasonic scanning and sonotherapy is regarded as safe, there are some potential deleterious effects. > > One of the most well known effects of ultrasound is that as Ultrasound waves pass through a tissue they tend to heat it up. The tissue can easily be warmed to 40 degrees Celsius. Although in vivo the heat is usually easily carried away by blood circulation or simply dissipated into surrounding tissues. this regiment can be applied in a technique called Ultrasound therapy where this heat is used to stimulate repair to damaged internal tissues. Another well known effect of Ultrasound are cavitations. Cavitations are small bubbles of gas that are released upon exposure to extreme negative pressure. These bubbles can cause cells or even tissues to rupture. > > > Source: [Effects of ultrasound](http://www.wikilectures.eu/index.php/Effects_of_Ultrasound) In the case of the *nachtkrapp* it can be assumed its high-intensity ultrasonic 'beams" will be powerful enough to cause deadly harm to those who are unfortunate enough to see this fatal fowl, sorry, dread harbinger of death who flies by night and preys upon little ones who don't go to bed early. [Answer] You could have your bird (which I envision as a large owl) possess the [**evil eye**](https://en.wikipedia.org/wiki/Evil_eye). The wings could have coloration around the holes like eyespots, which can be seen on the wings of some birds. These are lesser evil eyes. ![Owl with wings spread out](https://i.stack.imgur.com/lPvbi.jpg) From <https://i.stack.imgur.com/CNO7a.jpg> The evil eye is definitely bad and feared. People worry about it and wear charms against it - to this day. But it is not mechanistic. The ancient Greek philosphers were in no doubt that it was real but they could not explain how it worked. There is a huge body of folklore, from many different countries and you can borrow, mix or match. How does a bird with no eye have the evil eye? Maybe it does have an eye but it does not always show. It comes out when the bird wants to use it. I think it is creepier to leave up in the air how exactly the evil eye works. From a storytelling standpoint, if a person sees a bird at night and drops dead, further literary endeavors from that persons point of view will be limited. A person who sees the evil eye and lives - for the time being - still has agency and a viewpoint and can help make an interesting story. ]
[Question] [ I'm having no luck researching this topic so my terms may be wrong or my entire premise faulty. I have found a related question that might be a corollary: ["Can I kill a cyborg with magnetism?"](https://worldbuilding.stackexchange.com/questions/67546/can-i-kill-a-cyborg-with-magnetism/67562#67562 "Can I kill a cyborg with magnetism?") My setting is the distant future where sentient androids exist. They are electro-mechanical with no biological parts. I am writing under the assumption they would be susceptible to electromagnetic fields (EM weapons, superconductors, etc). Under intense magnetism their bodies will seize up, but in time they often recover because their skull and "bones" shield their nervous system. My question is about an alternate design of android that would be passive to magnetic forces, or otherwise resistant to the harmful effects. They are designed to operate within shifting magnetic fields inside a superconducting machine. My idea is that they are built on a similar skeletal frame that shields their nervous system, but their outer bodies are not susceptible to magnetism. They still function, think, and ambulate under conditions that would paralyze the normal androids. **Can an android's body be "immune" to electromagnetic forces?** And to prevent a world-breaking technology, why wouldn't all androids be made with this kind of body? What are the limits and trade-offs that make traditional electromechanical bodies "better" and these specialized bodies only suitable under specific environments? [Answer] So long as any electronic/electrically sensitive parts are completely enclosed in [ferromagnetic](https://en.wikipedia.org/wiki/Ferromagnetism) material and the input and output cables from these are [shielded](https://en.wikipedia.org/wiki/Electromagnetic_shielding), there shouldn't be a problem. As regards the rest of the body, use [paramagnetic](https://en.wikipedia.org/wiki/Paramagnetism) material like aluminium or ceramic. Ceramics are probably better in an intense EM field, as it won't allow currents to be induced within the body. Within a superconductor, though virtually all the field is outside the conductor. It would probably be simpler to use normal robots *inside* your hollow superconductor unless you have good reason not to. The reason to not use such robots outside such applications is cost; derived not from the robot being able to resist strong EM fields, but from it having to resist very low temperatures. Superconductors operate at nearly 0K, very few materials can sustain mechanical loading cycles at that temperature--in fact, I don't think there *are* any at present. Normal electromechanical systems will probably not work, you'll probably need centrally heated musculature inside an insulated body. [Answer] Most of the technology we have for manipulating electricity at present is narrow bandgap semiconductors based on silicon. It has only been in the last couple of decades that wide bandgap semiconductors have started to become used. Wide bandgap devices (GaN, SiC, GaAs) would have a better immunity although still be vulnerable to EMP or electromagnetic effects. If the information processing and control capabilities were photonic rather than electronic, then there would be an immunity to adverse effects from electromagnetic fields. If the processing is done with photonics, and motive capabilites are electrical, then you might have a system that is only temporarily incapacitated or damaged by strong EM fields. So replace electronics with photonics, and you explain immunity easily. Or use a hybrid photonic/electronic machine that is temporarily affected. I missed part of the question the first time around. > > "why wouldn't all androids be made with this kind of body?" > It would be a very expensive undertaking to build the facilities required to construct these specialized androids, and it would still be a low yield process. So it would probably be a government or military "cost is not an issue" type project. > > > What are the limits and trade-offs that make traditional > electromechanical bodies "better" > and these specialized bodies only suitable under specific environments? > > > Any machine that has to function in a very high strength magnetic field will be subject to induction heating, if it has ferrous materials in its construction. So design has to look at tradeoffs of cost and function. Example: Assume that the nervous system is photonic, and the muscular system is based on wires made of shape memory metal. The muscles are then actuated by temperature changes. This would mean that the entire musculature would require electromagnetic shielding from superconductors. And the supeconducting effect itself fails above a certain gauss level. So there would have to be a chilled exoskeleton of ferrous metal that damped field strength enough to allow a superconductor layer to effectively shield sensitive internals. We might well imagine that such an android has a tank of liquid nitrogen on its back to feed these demanding requirements. [Answer] Use photonic computing [wiki](https://en.wikipedia.org/wiki/Optical_computing). > > Optical or photonic computing uses photons produced by lasers or > diodes for computation. For decades, photons have promised to allow a > higher bandwidth than the electrons used in conventional computers. > > > A bit more detail from the article: > > The fundamental building block of modern electronic computers is the > transistor. To replace electronic components with optical ones, an > equivalent optical transistor is required. This is achieved using > materials with a non-linear refractive index. In particular, materials > exist[4] where the intensity of incoming light affects the intensity > of the light transmitted through the material in a similar manner to > the current response of a bipolar transistor. Such an 'optical > transistor'[5][6] can be used to create optical logic gates,[6] which > in turn are assembled into the higher level components of the > computer's CPU. These will be nonlinear optical crystals used to > manipulate light beams into controlling other light beams. > > > You could build the frame out of plastics, ceramics or other non-ferric materials. If you can make artificial muscle fibers that react to light, you can have a non-magnetic robot that can think and move. [Answer] I would use a material on the android which doesn't conduct electricity. If the electricity can't get to the nervous system, then the android wouldn't be affected. The second solution would be to use a material that dampens electromagnetic waves. [Answer] Electromagnetic radiation is harmful to integrated circuits because it can induce current, misfiring and potentially damaging them. If a circuit is only rated for 1.5 volts and power briefly surges to say, 1,200 volts for a few milliseconds then you're probably going to find fried electronics upon inspecting the cause of the outage. Aircraft (and for that matter, satellites, space stations, etc..) that get exposed to more radiation than we do on Earth sheild systems like this using grounded copper plating - like you'd find in any computer case. That's probably enough to sheild against 50-100 dB of EM radiation. Increase the radiation and you need to increase the shielding. You could theoretically put a computer inside a nuclear reactor if it was shielded enough - say with lead. But lead is heavy and more weight means more power needed to move. This wouldn't be a useful feature for robots not intended to operate in that extreme environment because the extra sheilding / weight would be very energy inefficient for locomotion. If some new sheilding method that was more weight efficient was invented, then it would be easier to standardize. ]
[Question] [ # Situation It is 2000 BCE. Seven late bronze age clans descended from the [Fatyanovo-Balanova Culture](https://en.wikipedia.org/wiki/Fatyanovo%E2%80%93Balanovo_culture) which have been warring for control of the Moskva after the disappearance of their culture have finally been united and are currently developing small crops. # Target A collection of tribes with modern-day levels of technological, scientific, medical and mathematical knowledge and complexity, a history going back to the Bronze Age, and much closer to an ecological equilibrium than we are today. If that is too vague, think of a society with our technology, but on a **much** smaller scale (I imagine the capital would not need a population greater than 250,000), with a guiding principle in their activities being "Consume less before doing more." # Identified critical elements These are elements I identified as being crucial to the development of modern-day technologies: 1. Development of recorded communications, e.g. writing (assume a transition from wood cuts to pictograms to a syllabary) 2. Development of rigor (I have isolated this as being necessary for precision, a fundamental trait in most modern disciplines) 3. Development of the scientific method 4. Discovery of denser sources of energy (I have already decided on charcoal as the first one) - Be conscious of (un)sustainability of practices (e.g. regulation of charcoal production following its discovery) # Question How would N° 2 & 3 occur in a tribal setting? Is there some plausible cultural loop-hole that would allow the tribe members to become sufficiently rigorous to develop theories, experimental to prove, disprove or correct them, and architectural to use them create designs and projects using them? And if they are incompatible with cultural values of a tribal society, is there some process by which a tribal society can reach them without altering too much its composition? **EDIT:** I should also have added that I envision the expansion to occur through a combination of population increase and absorption and integration of other tribes. [Answer] I would think it is possible, given a strong tribal demographic and plentiful resources. You would need a society that values discovery and invention and through natural breeding becomes more intelligent as a group. Most early breakthroughs were made by individuals, you are getting a group of brilliant minds over time. All eager to make their mark and attract the ladies who are no mean shakes at the brainwork themselves. Teaching skills make a big difference as well. Minds can be trained from a young age. This could come about purely through the invention of a new weapon that made them stronger in war. It would only take one person to get this started and through a combination of luck and design perpetuate to become the norm. Almost everything in early tech was invented by an individual or small group. If your tribe selectively gave an advantage in breeding to their most inventive and intelligent members it would upscale over time the mental attributes of the whole group. The rapid advance of tech these days is not just because we have random individuals working on an idea. But because we value inventions and breakthroughs highly and people are being trained from childhood to build on it. Agricultural societies often have a lot of time on their hands, planting and harvesting are times of frenetic activity, but in comparison to hunter gatherers who spend much more time foraging, they have plenty of time. This and warfare would probably be their first focus for tech advancement. As it was with societies these days. Give them an advantage over their neighbours and they can develop more leisurely and theoretical tech if there is a marked incentive to do so. If they're focusing on science then they won't be overtaken by other groups who aren't. Short term and specific focus as you get in wartime is not the same as long term cultural general focus. [Answer] **You won't get modern technology level. There is simply no way.** The simple problem is what I would call the infrastructure of knowledge: * You need time to develop things. The tribal way of life consumes much more time for food finding than modern method, *every single person is important to gather food.* Having time for own inventions is a luxury. Even agriculture in the beginning has problems: If you compare the crops, old crops are unbelievably small, you need much more work to get enough to eat. * You need logistics to to have a continous source of food. If you look at the beginning of civilization, math was developed for exactly this reason: Get an overview how much of the things are needed. * Modern technology needs a specialisation level which is not achievable with a tribal background. You need people writing things down, calculating, creating metal, wood, tools....the whole industry. If you think about the Industrial revolution: They needed many, many people (manpower) and the ability to nourish them when they are not gathering food. *So how to create a competent civilization*: Michelangelo, Boticelli, Raphael and Leonardo da Vinci were one of the most important artists in the Western World and they all lived at roughly the same time in Florence, Italy. What you need is a nucleus, a freak accident where some geniuses meet together and by working together are able to develop a culture. This culture in return attracts curious and inquisitive younger people. While modern age is out of reach, some impressive technology could be achieved, look up the four inventions of China: Compass, Gunpowder, Paper and Printing. Steam machines have been described by Greek polymaths, the Antikythera device uses a highly-sophisticated gear. [Answer] They would need a culture encouraging creativity and learning and the kind of laziness that makes you search for more efficient ways to solve a problem, i.e. people should first learn everything their tribe knows, then be given free time for creativity. Then they could just be lucky. Most ground breaking inventions/discoveries are trivial in hindsight, i.e. they consist of a single great new idea on top of all the previous knowledge, with a good piece of luck involved in finding it. I think the easiest justification for this would be some kind of religion. I say religion because this is a good example of how lots of people do things which at the time (or ever, but that is not the point) don't make a lot of sense (in the context of what they know). So have a religion which strongly encourages what I describe above, this could conceivable speed up the advancement of society a *lot*. Then after an initial success, it would become clear that it's really a good idea, and faith would be supplemented by reason. This can't work with too much scarcity, they need food security for this, and food security without occupying all of the tribe with it (or even the largest part of the tribe). I don't think this is much of a stretch, in reality people just never had the mindset I described above (not today either), they would waste their surplus on other stuff, like luxuries for their leaders, or churches, or sacrifices for some god, or war. Then after the first stretch based on luck, each previous invention/discovery would make the next one easier, would make them safer from invasion or hunger and you would need less and less luck. Of course this is purely speculative and rather unlikely, but what isn't... [Answer] So, the biggest problem here is time. In the comments you mentioned that things can happen over a longer period. Without going into specifics (That I'll freely admit I'd probably get wrong), your tribe would be eclipsed by the rest of the planet, fairly rapidly. This, however, can be a good thing. Contact with the outside can let them see the negative impacts of (mis)use of certain technologies, and allow them to figure out sustainable methods for them. This allows for most of your points to be figured out fairly easily - They're modeled after the others who figured it out first, and then studied and adapted to make sure they're sustainable. With modern technology, you can manufacture quite a lot using only a little, provided you have access to a boatload of resources. A small tribe would not, but with outside contact they would be able to bring stuff in from elsewhere. The biggest issue that I see is having this tribe manage to avoid colonialism and some big empire gobbling them up and exploiting them. [Answer] *"A collection of tribes"* (in modern times such a collection of tribes is called a *nation*) *"with modern-day levels of technological, scientific, medical and mathematical knowledge and complexity"* already exists, centered right on the territory of the ancient Fatyanovo-Balanova Culture; you may have heard of it, it is called Russia. It is indeed *"a society with our technology, but on a much smaller scale"* -- Russia has only 2.5% of the world's population. It is *"much closer to an ecological equilibrium"* than many other countries -- three quarters of its immense territory are very sparsely populated and quite free of human intervention. And its guiding priciple does seem to be *"consume less before doing more"* -- otherwise it would be hard to understand why it always chooses to isolate itself from the world instead of engaging fully in the global economy; anyway, for the last few centuries Russians consumed much less then people in other countries with a similar level of scientific and technological development; it may not have been their dearest wish, but under the protective care of various Czars, Secretary Generals and Presidents they surely had no choice but to consume less. The only snag is that the capital of Russia is a megalopolis and not a small city; but this is just a political choice: most people in Moscow work in services and industry, not in government. If the Czar wanted it so, the capital could move to the Greater New City, [*Veliky Novgorod*](https://en.wikipedia.org/wiki/Veliky_Novgorod), which does indeed have a population of about 200 thousand. ]
[Question] [ It is the 10th Century and the hero, [Ibn Muadhe](https://en.wikipedia.org/wiki/Ibn_Mu%CA%BF%C4%81dh_al-Jayy%C4%81n%C4%AB) has discovered trigonometry about six centuries before Cartes, and has received a wonderful gift. A very spiritual Avicenna had rushed by camel and horse from Persia to bring two special stones each the size of a person's hand, which can communicate with each other much like present-day telephones, with exceptions. They can only communicate by *a straight line* and only through atmosphere. They can work in rain and fog, not that I imagine that's a huge issue in Al-Andalus. The Caliph of Cordova is fascinated and has demanded Ibn Muadhe establish a communication system as far as possible for strategic purposes. [![enter image description here](https://i.stack.imgur.com/9pTZW.png)](https://i.stack.imgur.com/9pTZW.png) The problem lies in the fact that this is 10th Century Islamic tech in what is now southern Spain, and, as well, Ibn Muadhe knows the Earth is of course spherical and not flat. Using this tech and the resources of the Caliph's coffers, **how can he get these two magical stones as far a distance as possible? And how far would that be?** I'm thinking tall structures with the stones atop, but hoping for a creative solution using the properties that are allowed and the technology level involved. I'm willing to bend the rules of the properties of the stones *just a bit* if it can get me a really great distance in a clever way. [Answer] # This is a common nautical problem One of the first things you learn as a sailor is how to find navigation guides. For a lighthouse, for example, you need to know [how far away you can see it](http://www.boatsafe.com/nauticalknowhow/distance.htm), so you can estimate your distance when you first see it at night. For each of two elevated objects, you multiple 1.17 times the square-root of your height of eye (or height of object) to get distance to the horizon. Then add the distances for two objects together to get total visible distance. # How big were structures in the 10th century? The tallest building in the 10th century (and, infact every century until the 13th) was the Great Pyramid at Giza. Taking a look at the other buildings I could find, not many (if any) were over 100m. # How far can we see with such structures? So using 100m (328 feet for our thumb rule), we get a distance to the horizon of about 21 nautical miles. So with two such towers, we could expect to see around 42 nautical miles, or 80 km. Therefore, we can assume our straight line comms will work for about 80km. For Cordoba related references, Jaen is about 80km away, Sevilla is 120, Malaga is 135, and Toledo is 230. # But wait! There are mountains in Spain, and those are going to give you a much more significant height advantage than towers. Grenada is about 740m, while Cordoba is at 120m, for a total height difference of 620m. If we put a tower on top of a 620m hill, we get about 57nm to the horizon, for a total of 145 km. Conveniently, Grenada is 130 km away from Cordoba, so just about perfect for this communication method. # Best alternative? Another method would be to put one message stone on the top of a tower at a high point of a mountain. For example, Pico Veleta is about 3398 m tall, and only 25km from Grenada. The mountain-to-tower range from the peak of that would be about 265 km. Thus, if you make Grenada your capital city, you could communicate with a ~6 hour delay for a fast rider to take a message up the mountain, over most of Andalusia and to the Tangiers and Nador on the African coast. [Answer] If the stones use EM spectrum, just bounce off the ionosphere. If they use lasers, mount primitive prisms on poles every twenty miles. If they are message passers, fire them up on ballista. If they.... The issue you are facing is that any sufficiently advanced magic is indistinguishable from technology. You could use any method, up to and including mounting a hermit every fifty miles to swing a live cat in circles thus powering the stones to bend. Poor cat. [Answer] I think that terrain will get in the way more than the curvature of the earth. So do what you would do to get over local obstacle. Place them on mountain tops with a semaphore system from mountain to base. Invent hot air balloons and use those as your communications links. [Answer] From eyesight to horizon on a "Flat" surface, you can see about three miles. For an observer at the top of a Battleship (About 180 feet), you can see around 16 miles. The tallest mountain in the area you've specified is [Mulhacén](https://en.wikipedia.org/wiki/Mulhac%C3%A9n), which is about 11,400 feet tall. Establishing an outpost on the top of that would give you a distance of about 130 miles *theoretical* distance. Of course, things like other mountains might get in the way, so it's unlikely that it will get that far. If you had more than two stones, this would be a lot more useful (Climbing mountains isn't exactly the easiest thing), since you could relay a message to the top of the mountain, and then have the mountain relay it to someone else. **BUT** you specified two stones. The usefulness of placing one of the stones on the mountain is probably not that great, since you'd still have to send messages up and down the mountain. Honestly, a system of [semaphore](https://en.wikipedia.org/wiki/Flag_semaphore) stations space out on mountaintops, etc would work better for quicker communications. Instant communication stones sound like a really great idea for long-distance communications, but where they could **really** shine is in *short*-range communications. Like in combat. You can often see what your other section is doing, but communicating to them can be hard. Instant communications with two sections allows for much faster response time. No need for runners, no need for flags, or trumpets, etc. **EDIT** Oh, and a tool that is useful for figuring out how far you can theoretically go can be found [here](http://www.ringbell.co.uk/info/hdist.htm). [Answer] If they work through rain and fog, I'm assuming water doesn't stop your magic stones communications, so the answer from there seems obvious use the stones across oceans. As has been pointed out in other answers, mountain tops give you additional line of sight over the horizon, if they can communicate through ocean water this would increase the apparent elevation by a lot. The Mediterranean is ~1500 m deep on average and the Atlantic is ~3300 m deep on average, essentially communicating across water *is* between mountain tops. For comparison the highest point in the Iberian Peninsula is Mulhacen at 3,478 m. This could potentially allow communications between the Balearic Islands in the Mediterranean and the mainland (~100-200 km), across the Mediterranean to North Africa, or longer distances between ships at sea. The ships at sea in the Atlantic would likely be the longest distance available up to 400+ km apart (like communicating between two 3,000 m tall mountain tops), but isn't likely to be the most useful strategically. ]
[Question] [ I read that our current method of cryonics involves replacing blood with other fluid and keeping the body submerged in liquid as well as on ice (these things being done to the dead, for now, instead of intergalactic explorers and such), and that the process of waking a person up from this sort of 'cryosleep' (if they were alive when put under) would be intensive and time-taking. I'm wondering if there are any (probably hypothetical) alternatives to the method we have now that would have a shorter wake-up interval or no real protocol for that at all (where a person in cryosleep could just wake up without assistance or any real, serious injury). How could this sort of technology realistically exist? [Answer] I have a few ideas about this, though only the first is really relevant to your question. ## First, # Hibernation! > > Often associated with low temperatures, the function of hibernation is > to conserve energy during a period when sufficient food is > unavailable. To achieve this energy saving, an endotherm will first > decrease its metabolic rate, which then decreases body temperature. > Hibernation may last several days, weeks, or months depending on the > species, ambient temperature, time of year, and individual's body > condition. > > > So, assuming we figured out a way to introduce this ability into humans, then people would be able to go into a deep sleep for up to months as a time, or even longer if an outside source of nutrients were provided to the sleeping patient. In a sense this would be similar to an induced coma, and would be a good way to pass the time by if that was your goal, but it would have detrimental effects on things like muscle mass. NASA I believe is actually contracting a company to create a system to put astronauts asleep for most of the journey during any future trips to Mars. This will be so they can greatly reduce the required size of any crewed ship they may someday send to the red planet. <https://www.nasa.gov/content/torpor-inducing-transfer-habitat-for-human-stasis-to-mars> ## Second, Use the method that you mentioned. Sometime this year there will be an attempted head transplant (yes, I did say head). They will have their blood drained and all that good stuff and we will be able to see if they're able to wake up after words, although there will be additional concerns that this guy will literally have a new body as well. ## Third, If this involves space travel, then reduce the need all together by traveling near the speed of light. This will cause a time effect that will make it so that for passengers on the ship only a fraction of the time required for the journey will have passed for them. Hopefully one of these has helped or given you some ideas. [Answer] [Larry Niven's 'Tales of known space' stories](https://en.wikipedia.org/wiki/Larry_Niven_bibliography) used ['stasis fields'](https://en.wikipedia.org/wiki/Stasis_(fiction)); where he postulated devices that could stop (or slow greatly) any passage of time inside a limited volume. Stasis fields (and stasis boxes) have been used repeatedly as a science fiction concept not only as a replacement for cold sleep during star travel but also to replace refrigerators to preserve food, a way to safely store anti-matter or dangerous creatures, as weapons, and many other uses. [Answer] The problem with freezing is that tice crystals form in the blood and rupture cell walls. Removing the blood prevents this problem. Freezing the body slows the metabolic processes almost to a stop and frozen cells kind of get surspended. Replacing cryofluid with blood takes time, and I guess you probably want to warm up rather slowly. (I am not a mad scientist but if you warm things up rapidly they can heat unevenly and rupture) If you want to revive quickly, freezing is probably out. I guess you could invent a substance which prevented ice crystals from forming, this would remove the need for the transfusion, but raising the body temperature from way below freezing to body temperature and restarting metabolic processes is going to take some time. Freezing mimics time slowdown by reducing molecular motion, is there some way to fake that? ( I mean unless you just want to posit time stasis pods). Ok this is going to be a long trip, so stay with me. Freezing slows the vibration of molecules, nothing moving means metabolic process just kind of pause. No glucose is consumed, no oxygen is required. Freezing is a faked time out. But heat is just the vibration of molecules. Vibration can be countered by an opposite vibration (noise canceling headphones work this way). Each substance has a different vibrational frequency (this is why earthquakes can cause the tops of buildings to explode --match the structure's vibrational frequency and the energy builds and builds). So, scan the body, you need to invent a scanner, something that passes through normal matter almost effortlessly, the key being almost. The interference pattern for each type of molecule will be different. A supercomputer then needs to map the body and calculate the opposite vibrational frequency at every point. The stasis pod protects an opposite vibrational frequency for every part of the body, trillions of different beams. (You also need to invent the beam transmitter which can project the beam to precisely the right point --maybe two beams that only cause an effect when they meet) Molecular activity ceases instantly. Also can be switched off instantly. BAM, instant cruogenic sleep and wake cycles. [Answer] Realistically, yes. You could build a capsule that slows the time for a single person. Capsule would probably need to be spherical. How to achieve that is beyond our knowledge though. This guy takes a crack at time dilation as a field, might help: <http://file.scirp.org/pdf/JMP20120200010_34720787.pdf> [Answer] I don't know much on the topic, but I think worthy of thought is the possibility of genetic engineering of individuals selected for space travel to allow relative stasis and thus long time travel in space. As rclev has already noted, hibernation is a possible option and this would probably be the most easily achieved, possibly this could be partnered with some kind of anti aging technology (<https://en.m.wikipedia.org/wiki/Biological_immortality> as i am aware that aging continues but may be slowed during hibernation. However this might cause problems for other aspects of your world, so maybe aging in hibernation could be explained away, slowed sufficiently or ignored. While this might take more time than hibernation for wake up, there is also the possibility of genetic engineering to allow simply freezing and thawing be viable options for cryosleep. There are organisms that exist that have developed the ability to withstand/survive freezing temperatures (<https://en.m.wikipedia.org/wiki/Cryobiology>) and maybe this ability could be passed on somehow to your intergalactic travellers, possibly by genetic engineering or by some sort of injection of antifreeze proteins or some substance that stops nucleation and crystal formation. As I understand it some of the problems with freezing organisms are due to the formation of large ice crystals which destroy cells, so possibly some mechanism which allowed cells to withstand more stretching and stopped large/sharp crystal formation could be implemented. ]
[Question] [ I want a realistic event to occur that kills the majority of the Earth's population. However, the nature of this event must not effect humans or machinery currently flying at high altitudes (those of passenger airplanes). The event can be singular or be multiple events occurring simultaneously around the globe. It should also be unexpected -- commercial airlines would likely be prohibited from flying if threat of nuclear war was escalating (and then acted on while the airline is in flight). Natural disasters are not quite relevant because they cannot match the cataclysmic scale of wiping out everyone on the surface simultaneously. [Answer] You can find such an apocalypse in the Genesis: [the Deluge](https://en.wikipedia.org/wiki/Genesis_flood_narrative). A Great Flood can allegedly kill everyone in the surface. You only need it to take just a few hours, to prevent airliners to run out of fuel, and the clouds causing the rain be must low enough to allow planes fly over them. Even if by the time the planes run out of fuel waters are still high (but calm), [airliners can ditch in water](https://en.wikipedia.org/wiki/US_Airways_Flight_1549). Most people won't say this answer is science based, but even if you don't believe literally what is told in the Bible, there have been a lot of attempts to give scientific explanations to the deluge. Probably none of them would hold a serious scientific scrutiny, but anyway they are about the level expected in science based Worbulding SE questions. [Answer] The cell-phone delivered rage-inducing subsonic pulse described in the first Kingsman movie might fit your needs. At least for those planes which aren't equipped with hardware to let passenger cellphones work at altitude. [Answer] Two alien races have been duking it out between the stars. The difficulty of moving things between the stars has caused this war to strongly favor the defense, hence it has become a war of stealth rather than battle fleets. Race #1 paid a visit to the solar system. They were detected by the enemy who mistakenly thought it meant they lived here rather than just passing through. Missiles with a nanotech warhead are dispatched, when they enter the solar system they find only two targets emitting electromagnetic energy: Earth and Mars. They're very stealthy, we don't even detect them, let alone try to shoot them down. One missile goes for Mars, the others go for Earth. The missiles release a huge number of pellets designed to deliver their weapon through the atmosphere while minimizing reaction time and the ability of point defenses to destroy them, a classic time-on-target attack. The nanomachines are not all that sophisticated (there's a limit of how much computing you can put in something that small), human beings are a sufficient match for their target parameters. While it isn't a grey goo attack the machines do replicate and spread, quickly killing off everyone they can reach. Their target species does not use aircraft so there is no provision to attack targets in the stratosphere. The whole point of using a nanotech attack is to take the planet intact rather than simply destroying the biosphere, thus the machines soon deactivate. By the time the planes land it's all over. [Answer] Sudden emission of carbon dioxide, similar to what happened at Lake Nyos <https://en.m.wikipedia.org/wiki/Lake_Nyos> Could be due natural processes (previously unknown process inside mantle causing co2 rich magma to suddenly de-gas) or man-made: act of terror on global scale forcing sudden release of co2 from commonly used sewage treatment devices underneath most of cities in your world. [Answer] With hard science and modern technology you can't killing off humanity in a couple of hours requires some form of high energy destruction, no disease can do it. And anything energetic enough to wipe out humanity all across the globe will kill aircraft as well. The only thing that will work is some kind of delayed well timed kill event like a nanobot attack, where the bot spread out over time long before the aircraft takes off. Then some kind a of one time signal triggers them to kill all humans and bots above a certain altitude don't get or don't react to the signal. [Answer] There is a clue in the Andromeda strain and also most Zombie universes. The problem with the Andromeda strain was that the virus mutated so quickly it became non-virulent. However, it was airborne and quickly spread to all people. So now you have everybody busy coughing on others and then dying. What about the people who ran into an air-proof room or sealed themselves? That's where the zombie component comes in. Before the virus kills the host, it causes the infected to do things that are not logical and damage the life support of anyone in an airproof location. The virus can infect anyone through the air and water. However, the virus has a heavy molecule that makes it mostly heavier than air (though still light enough to drift at nose level). So at altitude there would be no concentration of viruses. People in comercial planes may survive. [Answer] That asteroid killed all the dinosaurs and lots of other stuff besides, and did it in a day. The mechanism: asteroid hits, splashes material up and out. Then many many reentry events heat the atmosphere too hot for life. It only stayed that hot for a day or so but that is more than you need. <https://www.psi.edu/epo/ktimpact/ktimpact.html> Boiling hot atmosphere for a day would do for most people on the surface. A bomb shelter or deep basement would be ok for a while but you need air in there. Most air conditioners use outside air as a heat sink which would not work if air was 100C +. You might survive if you had a large volume of water as a heat sink or a tight, deep enclosed place with enough air to tide you over. I am thinking now about the pressure effects on the atmosphere in a cave if the air outside were 100C. There would be some serious wind. It is cool up in the upper atmosphere and so a long flying plane would be a fine place to ride this out. Unless you got hit by one of the pieces of crust re-entering. It would be quite a world to return to. ]
[Question] [ If the moon had life and it progressed at the same rate as life on earth, including key points of technological discovery. When would we, on earth, have first detected them? Technological discoveries I mention are things like... fire, Stone Age, Bronze Age, industrial revolution, etc... first telescopes, electricity, radio, flight, etc... (Obviously ignoring the fact that the moon is lifeless with no atmosphere) There is no doubt that by now we would know they are there. We would receive the radio waves they emit. We have satellites that would clearly see their cities and road infrastructure. Before that there could be electric lights lighting up at nighttime that could be detectable by powerful telescopes. But in the past we wouldn't know they were there. So there is a point when the first discovery was made. What point in technological advancement would be the earliest point where we would have noticed them without knowing they were there and realised that they were a civilisation. [Answer] Percival Lowell speculated that there was life on Mars based on (erroneous) observations of "canals" and what he thought were changes in the Martian landscape that could be explained by seasonal changes in vegetation. This was with some of the best telescopic equipment in the late 1800's, but as we know now, his observations were coloured by wishful thinking. Observation of the Moon would be equally limited until very late in the Industrial Revolution when not only would *we* have telescopes of sufficient size and quality to make out larger surface features, but also *they* would also have started making very noticeable changes to the Moon. Agriculture, especially large scale agriculture like the settlement of the west and replacing grasslands and open ranges with fenced in fields and growing new crops like wheat should make visible changes, especially during seasonal changes when the fields are fallow or new crops are growing in. The invention of electric lights and urbanization would provide clear beacons for observers on Earth, and the Lunar inhabitants might also be making active attempts to signal the Earth if they are also as sentient as we are. [![enter image description here](https://i.stack.imgur.com/Y5naw.jpg)](https://i.stack.imgur.com/Y5naw.jpg) *The Korean Peninsula at night from Orbit* In the early 1800's some speculative ideas for signalling the presumptive inhabitants of Mars included ["drawing" massive diagrams across the Sahara desert or carving out huge diagrams](http://listverse.com/2013/06/08/10-interesting-attempts-to-communicate-with-aliens/) in the forests of Siberia which would be visible from space, and presumably visible with a large telescope on Mars. Such structures would be visible from the Moon as well, and a Lunar engineering project of similar scope should be visible from Earth. [Answer] Artificial light is very visible from space and we would definitely see that eventually. In early civilizations there generally isn't too much of it though, so it wouldn't become all that visible until the invention of light bulbs or good telescopes. A more visible effect of human habitation would be agriculture. With the naked eye it's hard to tell cultivated land from plains, but people would have started mapping the moon very early on in history, and would likely notice forest lines receding and being replaced by agriculture. This would at least imply intelligent life, but there would be debate as it *could* just be forests naturally dying off. Still, this should be slightly visible to the naked eye and could have been detected and theorized as early as the dawn of detailed map making (Classical period). But there would be no confirmation of this until the invention of telescopes. [Answer] The presence of large scale civil construction like roads and canals would give hints especially if we can watch them forming, crawling across the landscape. But artificial light would be a big hint, even widespread campfires can give off significant light. All this would require the invention of telescopes on our part of course. If there is obvious liquid water people would presuppose life, if not intelligent life, very early. [Answer] See [this question](https://astronomy.stackexchange.com/questions/12493/visibility-of-human-activity-on-the-moon) on Astronomy.SE. Earth-based telescopes cannot see small details from that distance because of fundamentals of optics. Without primary mirrors *hundreds of meters* across, we won’t see their roads. Large scale features due to building cities (several km across) or changes due to large scale agriculture will simply be spots of a different color with no way to tell *why*. Even if there is a geometric pattern that speaks of “living growth” we can’t tell if it’s beings or invasive bugs. Maybe we’ll get lucky and see large-scale structures based on obviously intelligent patterns like prime numbers. But in general, I think we can’t be sure there are people there until large scale artificial lighting is rolled out. ]
[Question] [ I'm trying to figure out how a minimalist style society would work. Its secretive founders have been planning this since the 19th century, hiding in universities, influencing the young to attempt to develop the desired technologies. They hope to wait for the natural collapse of complex global society and swoop in when their time has come. Their ultimate goal is to create a civilization which could last 100000 years. In order to do this they plan to optimize certain aspects of the human condition and transcend certain memes and schema about how basic human activities must work. They want to transcend the schema surrounding entertainment, they want to replace it with soma (pleasure chemicals), wireheading (stimulating the brain for preferred mental states) and emotional discipline methods (e.g meditation). They want to transcend the schema where food = plants/fungi/animals. Just as vehicles use fuel to continue existing, so can humans use "body fuel" to sustain their existence. There needs to be some way to turn raw materials into body fuel which is as cheap or cheaper than agricultural methods. [Answer] Bacterial processing of waste matter into bioavailable nutrients. Raw materials (sewage and refuse and yes even dead things of all types because leaving amazing piles of raw materials around is silly, as well as some small additions from the wider ecology because there are always losses in recycling no matter how much of a closed loop you intend) are dumped into vats to be digested by engineered bacteria (biological chemical factory) which break it all down into component parts. Running materials through a grinder first would speed up that process a bit by feeding in a fine mulch rather than large chunks, but generally you let the bacteria do the work. Some energy sources will of course be needed to power this process - sunlight is traditional, though artificial light is more likely (and would allow much better density of production with no downtime). Specialized vats would be used to produce specific vitamins or fix particular nutrients, to be mixed as needed for different formulations. Fortify this with some additionally sourced materials (necessary simple inorganics like iron, magnesium, potassium, etc), and you could mix it all together at the end of the process for a single nutrient slurry. It wouldn't be all that different from growing more traditional crops using vertical farming, essentially the vats of bacteria are the plants in agriculture, but could be more simply automated and achieve enormous economies of scale. You recycle organic (and some inorganic) waste using a continuous stream manufacturing system, for a food source requiring little labor (though high capital investment) and negligible land area compared to traditional agriculture. [Answer] **We can synthesize all the basic nutrients. Whether the results are cost effective or tasty is another matter entirely. TL;DR: We could, but I think I'm losing my appetite.** We can already synthesize carbohydrates (sugars, starches), amino acids (building blocks of proteins) and lipids (edible oils, fats and cholesterol.) The first key (formerly strictly biological) process automated was nitrogen fixation: <https://en.wikipedia.org/wiki/Haber_process> Making carbohydrates, via artificial photosynthesis is a topic of active research: <https://en.wikipedia.org/wiki/Artificial_photosynthesis> We now have programmable lab machines that can build custom proteins, just send them a file in a standard format and payment: <https://en.wikipedia.org/wiki/Cell-free_protein_synthesis> or search for: "peptide synthesizer" I'm not sure about the state of artificial synthesis for fatty acids and lipids in general, but (since we can make the enzymes that perform synthesis of fatty acids), I'm pretty sure we could, if there was a pressing reason to develop/scale up those processes. The main reason for agriculture is that plants (1) grow themselves and harvest the sun's energy. (2) can be encouraged to do so in/near places we want to live, (3) produce the nutrients we need, in forms we're well adapted to and enjoy. Unless there are surprises, like some vitamin or trace nutrient that is impossible to synthesize, I strongly suspect that we could make 'food' using strictly chemistry, without living biochemistry involved -- no cells needed. [Answer] # Use the People, for the People\* Obligatory [IMDB](http://www.imdb.com/title/tt0070723/) reference. You recycle your people (when they die) into food - there's lots of nutrients there to be taken. You don't need land, you don't need agriculture, don't need to provide and care for animals, you don't need hydroponics... If you start running out of people to use for food, find a way of killing more of them.... \*May require some processing [Answer] I've seen an anime ages ago talking about quite a similar topic, this case, in the case of long space explorations missions. First thing they did was to modify the human genome, yup, good old homo sapiens is not satisfying in terms of needs, we needed something more economical. They looked at what they would have plenty in space. Light and radiations. So it was decided, humans will now do photosynthesis. Humans became able to do a reasonable level of photosynthesis, they still needed a meal here and there, but it was in the scale of one every week. So boom, you have already divided your needs for food supplies by about 14. Now, for you remaining food needs, you should look into insects. Yep, these bad boys are darn healthy and provide lots of proteins, they are also way more efficient in terms of needs. Grind them into powder and add your bioengineered vitamins and you are ready to go. [Answer] Yes; in order for us to live, we need: * Proteins (actually, it's enough with the raw amino acids) * Fat, especially [omega-3 and omega-6 fatty acids](https://en.wikipedia.org/wiki/Essential_fatty_acid) * Carbohydrates * Vitamins and minerals * Trace substances All of which can be synthesized in a lab, then mixed in good proportions provided that we have decent precursors. However, it takes a lot of time and effort to do so manually, whereas nature is much more efficient. [Insects](http://time.com/3824917/crickets-sustainable-protein/) are not really a good way to go, partially because they might not produce enough in relation to the volume they will occupy, but mainly because *they need complex food*. In order to feed the insects, you need to grow and collect foods for them. That is, you still need to have agriculture and, thus, won't fulfill the question of stopping agriculture. So a more efficient way would be to [grow proteins](http://www.nytimes.com/2013/08/06/science/a-lab-grown-burger-gets-a-taste-test.html) from stem cells, to have [algae farms](http://www.slate.com/articles/health_and_science/feed_the_world/2014/04/algae_for_food_edible_algae_is_more_commercially_successful_than_algae_biofuels.html) or to bio-engineer yeast/bacteria to produce the stuff for us (no currently working tech). A benefit with this would be that we don't need to hassle with synthesis, the enzymatic building from the cells will not produce byproducts so there is no need for purification and all we need is to keep them in a vat and feed them with stock solution of liquified resources (and some UV for the algae). However, we now start to go back to borderline farming. Even though we don't do agriculture, it can be argued that you are still farming if you grow other life forms for food.... [Answer] Well, you obviously have canibalism. However, to provide enough literal 'human fuel' you'd need people farms, and ethics aside that breaches into agriculture. My next thought was not to adapt existing methods to suits humanity, but to adapt humanity to suit existing methods. Adding chloroplasts to our skin cells could, with a bit extra genetic tweaking, allow us to phtosynthesise. This would let your populace generate energy within dayight hours, reducing the need for food. However, photosynthesis requires Carbon Dioxide to work, and although by knowledge about genetics is limited, I would expect it to be an enormous challenge getting the human body to transfer CO2 to the skin. You *could* try getting it to draw CO2 in from the air, but that would also present what I expect to be massive difficulties. But carrying on the idea of adapting humans, you might be able to use, for want of a better word, 'artificial' energy to power humanity. By artificial, I mean energy we extract from fuels in power plants. Whilst this would likely be inefficient and your society wouldn't be too keen on it, having a way to hook humans up to stations and stone the enrgy inside them, possibly in batteries, would reduce the need for agriculture. However, why do you want to stop using agriculture in the first place? Plants are excellent sources of energy and nurients, we're just having some difficulties growing enough to support Earth's bloated population. But automated farms, ones that don't need humans to grow the food, would stop your population having to do the dirty work. All you'd have to do is reduce the population by a few billion, and you'd be sorted! (And hey, maybe canibalism wouldn't be the *worst* thing in this situation? 3 billion corpses, what else are you gonna do with them? Biofuel?) ]
[Question] [ This *should* be easy, given how close we sometimes seem to already existing in some kind of cyberpunk dystopian vision of the near future, but I'm having a bit of trouble imagining exactly **what the transition(s) to and structure(s) of corporate nation-states, as opposed to our present standard-fare representative governance nation-state, would most plausibly look like, given a starting point of roughly the early 2000s as the earliest possible point of divergence from the history you and I are familiar with as "true."** To be clear, I am talking about a very common trope of Cyberpunk - that nations, such as they are, will be balkanized, neutered little things, largely co-opted by the corporate interests with holdings inside their borders, in the future. That in many places there might actually exist districts, cities - even states with ONLY corporate and/or criminal syndicate power structures in place. It's a wonderful thematic tool for pasting the oppression, corruption, waste, and inhuman bureaucracy of authoritarian governments onto the template of corporations in order to criticize extreme visions of unrestricted capitalism, but is it plausible, and what would it look like? Subquestions within this overall question that would add to any answer: * What would the relationship between corporation and nation look like? * What would be the most common relationship between employees and corporations look like? * How would corporations change? * How would concepts of citizenship, suffrage, and legal representation for individuals and organizations change? * Would there be any semi-stable transitional stages from government rule to full-blown corporate hegemony? I am going to attempt to elaborately answer this question on my own, but I won't be selecting it as the answer unless for some reason it is upvoted the most, and users should also feel very free to criticize/nitpick my answer as a form of contribution. [Answer] One way this could develop from current events is from corporate-run "smart cities" such as [Avasa in India](https://www.theguardian.com/cities/2015/nov/19/inside-lavasa-indian-city-built-private-corporation). There are projects like this at least proposed all over the world, as the ultimate in privatised supply of public services. The idea is that private company funds, plans, and operates a high tech, fully integrated, city. All the tasks which might traditionally have been performed by local government are instead departments of this private company - transport, power and water supply, emergency and medical services, schools, etc. As a consequence, a large proportion of the residents are in fact employees of this one company - and it's not hard to imagine the city exporting goods or services from yet more fully-owned enterprises. In return, these corporations are able to set the rules of how all these services run - rules which would in any other city have been imposed on them by public bodies before they were awarded the contract. Now imagine that these cities are a success, and the rest of the country they're hosted in is in a long economic decline. The corporations will accrue ever more money, which they will want to invest in expansion, and the waiting lists for residence of the new cities will persuade the government to allow more cities to be built. Eventually, the corporations will start offering to "bail out" existing cities, converting a depressed slum into the latest branch of their franchise. As others have pointed out, the key power to take over is the police force, but it needn't be called that. Go into a shopping mall, and you will see uniformed guards, who have the power to evict you based not on the law, but on the rules decided by management. Scale that up to the size of a city, and you might find that a conservative Christian corporation manages to "outlaw" abortion, or homosexuality, simply by firing employees and evicting residents who don't follow its "contract". The surrounding state might allow this as a compromise of getting the investment, or it might simply lack the resources to compel the corporation to comply. I'm frightened and depressed how plausible this sounds, and now I have to go to sleep! [Answer] **Historical Precedents** *[The East India Company](https://en.wikipedia.org/wiki/East_India_Company)* The East India company basically ruled India. They directly competed with other East India companies, sometimes [violently](https://en.wikipedia.org/wiki/Battle_of_Swally), and enjoyed a monopoly on trade in the region sanctioned by the English crown. Thus while they were propped up legally by the English, the company itself often held sway in India proper. The nature of the power structure seems fundamentally to have been one in which the company posed as an intermediary between the west and the various regional principalities of India, controlling their governments by monopolizing the income available to them and pitting them against each other to keep them in check. They loaned the British government significant sums of money, essentially propping up Britain in dire straits and profiting immensely from its monopoly so bought in times of relative prosperity, where its products were readily consumed by the British public. The BEIC marshalled and directed its own navy and army in campaigns and garrisons, with personnel drawn primarily from the native population whose lands it owned. These forces [were used](https://en.wikipedia.org/wiki/Battle_of_Buxar) to enforce Company directives among the native governments. This force made the BEIC kingmakers. Such arrangements with local governments ensured the company did not incur the costs of governance - inimical to profits, especially when tasked with ensuring the compliance of native populations. This was fundamentally possible due to the power vacuum ensuing the fall of Mughal greatness by the rise of the Marathas and other Hindu groups in India - regional hegemony was in the hands of no one in particular. Company profit [was extracted at the expense of sustainability](https://en.wikipedia.org/wiki/Great_Bengal_famine_of_1770), to put it lightly. Regional stability and rule of law suffered consequently; India was in that time a nation ruled by a company and the thugs who did not get in its way. Its corporate lobby was responsible for things like the Tea Act, which precipitated the emergence of the USA - and the undermining of Chinese rule of law via international opium drug trade. Fundamentally, the BEIC was a joint-stock company insured by the British government and capable of almost unhindered operation throughout the subcontinent and much of the high seas. It was dissolved ultimately by an act of the British government in the wake of rebellion on the subcontinent which saw the company's military control of government there falter. **The BEIC was basically everything anyone could want of a horrifically omnipotent, octopoid, corporate stand-in for government.** *[Zaibatsu](https://en.wikipedia.org/wiki/Zaibatsu)* These large Japanese business interests get disproportionate mention in Cyberpunk, probably fueled by [western fears](https://www.jstor.org/stable/40720420?seq=1#page_scan_tab_contents) [in the 1980s](http://www.businessinsider.com/japans-eighties-america-buying-spree-2013-1), the decade in which we may say the genre was born. Fundamentally the amalgamation of a private holding company, industrial conglomerates, and a wholly-owned and backing banking organization, Zaibatsu basically ran Japanese economics, [including tax collection](http://www.sjsu.edu/faculty/watkins/zaibatsu.htm), especially prior to WWII. Their differentiation from criminal Yakuza is sometimes hazy, and they also ran political organizations and engaged in quite a bit of military-industrial complex-ing. Their employees [expressed considerable devotion to zaibatsu interests](https://books.google.com/books?id=uxeUzBdNGDwC&pg=PA8&lpg=PA8&dq=zaibatsu%20devotion&source=bl&ots=n3gst-bPSP&sig=ZJyoXohaTeeDa4jGEDLm-ls5NPo&hl=en&sa=X&ved=0ahUKEwiTss3iwZjRAhXFNSYKHTATA_EQ6AEIGjAA#v=onepage&q=zaibatsu%20devotion&f=false) likely stemming from [a cultural background encouraging such behavior](https://en.wikipedia.org/wiki/Salaryman). Their dominance came to an end with the fascist government of the 1930s and 40s nationalizing many of their assets. **Zaibatsu represent a blurring of the lines between family, corporation, government, and the individual, enabling remarkably stable and potent power structures to exist within a more powerful government.** *[Banana Republics](https://en.wikipedia.org/wiki/Banana_republic)* When you have a country whose economy is based on the profits of a few or even just one company, you have a banana republic. While in a large and complex way one might consider the BEIC's rule over India a kind of very large and powerful Banana Republic, the Latin American examples of history provide [a more recent and plentiful set of stories](https://en.wikipedia.org/wiki/United_Fruit_Company#Banana_massacre) to draw inspiration from. **Banana Republics expose salient features of corporations which assume features of the nation-state: effective monopoly on trade and the backing of a foreign power more potent than the government in whose lands they are doing business.** *[Organized Crime](https://en.wikipedia.org/wiki/Organized_crime#Bureaucratic.2Fcorporate_operations)* In a very literal sense, organized criminal activities constitute nothing less than the unsanctioned operation of a "government and corporation" within the borders of one or more nation-states. Whereas these organizations are forced by the extralegal nature of their operations to utilize security enforcement and legal codes of their own design in place of the systems they subvert, such groups are immediately to be considered candidates for cooperation with corporations wishing to extend their influence within jurisdictions these groups exert influence upon. These mafias often arise most powerfully in the presence of disadvantaged identity groups which help to guarantee the loyalty and trust which transcends loyalty to and trust in the governing organizations they supersede. In situations where these organizations face no real pushback from existing governments, they themselves [become the government](https://en.wikipedia.org/wiki/Barbary_pirates). **The Transition** Considering the above, it seems most likely to me that transition from modern customary representative nation-states involves the arrival of various converging states of affairs in a single jurisdiction: * Superior foreign backing * Local power vacuums * Corporate monopoly of trade * Displacement of trust and loyalty in the population from their governments to their employers and/or local crime syndicates. Interestingly, some of these seem to precipitate the others. If you have a corporate monopoly on trade and/or a large crime syndicate, local governmental power will ebb, leading to a power vacuum which makes it more likely a corporation backed by any number of more powerful foreign states could impose corporate rule over an area and win the short-tern trust and loyalty of a local population. I foresee a transitional period during which increasing income disparity and the instability of a maturing global market dominated by disruptive technological innovators leads to widespread disparity in the well-being of nation-states around the world. Such variation makes it possible for corporations to pick and choose nations willing to back them which may also be more powerful than nations in which these corporations which to do business, enabling them to easily play upon local power vacuums to get their way. Initial deficits in enforcement would be handled either by mercenary/criminal partnerships or by proxy government forces as already modeled in our historical record. There are not many clues about what kinds of corporations would be most apt for this kind of existence, but we may assume that both private and publicly-owned firms are liable. Ideally they will be international and liquid, capable of making large investments in new markets at the drop of a hat to take advantage of local imbalances. Conglomerates will be better positioned to take advantage of opportunities to establish monopolies on trade in a variety of areas. Unique company cultures with strong team-building aspects will probably also be prevalent among the early adopters of this company-as-nation move. One thing that is really only inferred from the above investigation, yet which I believe will also be fundamental, is a breakdown in international law. This is a somewhat surprising conclusion, since it had often been assumed that Globalization would make transnational conglomerates with immeasurable wealth and influence more common and therefore more likely to take advantage of smaller nations, but I believe that larger governments are too able to intervene in such affairs so long as the international community generally agrees on the legal aspects of such behavior. For a company based out of China to exert undue influence in a small African nation, for example, the world community of nations must not hear the voice of that small African nation or be interested in coming to its aid. How such a breakdown in international law would occur is a speculation more suited to an entirely separate question and will not be further investigated here. **The Stable Final State** The transition reaches stable equilibrium when no governments or government coalitions stand which are capable of or [interested in](https://en.wikipedia.org/wiki/The_End_of_the_Free_Market) toppling corporate nation-states, and such nation-states are ingrained into the fabric of the societies they do business in. There can be no [Economic Singularity](https://worldbuilding.stackexchange.com/questions/64407/plausible-original-concept-for-high-fidelity-apocalypse/64438#64438), since this destroys the concept of a corporation, so it seems that for such a future to exist we might/must assume widespread proliferation of monopolies resulted in siloed, proprietary knowledge economies without significant to-market contributions. What would the relationship between corporation and nation look like? It would be, in most cases around the world, one where a single corporate entity used the government as a proxy, or - as it might see it - a unique subsidiary public relations and regulatory asset. In other regions, government might have broken down completely; in these cases we would probably see corporations either pull out, leaving "criminal" enterprise to fill the power vacuum, or else very large corporations like the BEIC would operate as the government themselves at great expense - presumably for some correspondingly large profit. What would the most common relationship between employees and corporations look like? While some corporations seeking intense loyalty might end up [employee-owned](https://en.wikipedia.org/wiki/Worker_cooperative#Comparison_with_other_work_organizations) in a bid to devise some kind of representative citizenship with suffrage within company structures, the zaibatsu model seems the likely stable structure which would obtain, notably only after it had been incentivized for some time by the existence of and hiring practices used in large, stable monopolies which would encourage such shifts in loyalty. A more in-depth analysis of this question in light of the [rising contractor economy](https://www.bls.gov/careeroutlook/2016/article/what-is-the-gig-economy.htm) is probably worthwhile, but suffice it to say a traditional cyberpunk future dominated by massive all-owning corporations that for all intents and purposes own their employees as well is probably somewhat off the mark. More likely the majority of employees would be bought and sold as a commodity off the government to which they ascribe - perhaps yet another staffing firm or one of the largely relict nation-states. A small remainder would be salarymen, bound like samurai to their corporate houses. How would corporations change? Largely answered in the preceding questions, but of significant importance (and not yet broached) is the corporation's relationship with regulations. Without governments and non-profit regulatory agencies backed by governments to devise and promote market regulations, regulatory work must be done by corporations - especially considering most large markets would be made up of people basically working either for you or another competing conglomerate. Interfacing your Business Operating System with those of your trading partners would be a key concern, and would expand to include care for and build-out of infrastructure, as seen in some cases with the aforementioned banana republics. Many conflicts in such a future would surprisingly stem from disagreements over things like what file format to conduct purchase orders in, how to handle currency exchanges, what constitutes legal incorporation in a given jurisdiction, etc. How would concepts of citizenship, suffrage, and legal representation for individuals and organizations change? In such a future, citizenship is equivalent to employment by a company or perhaps consumption of its products at a distant remove. Suffrage is to be equated with stock holdings, and legal representation, while perhaps conducted in the form of a government court, is in fact dependent on the business relationships which obtain between the stakeholders in a case and may in fact devolve into outright violent confrontation where these stakeholders do not understand the power dynamic between them. Would there be any semi-stable transitional stages from government rule to full-blown corporate hegemony? I think that in fact such a future would represent a sort of semi-stable transitional stage in itself. It seems inevitable that such a future would sooner or later collapse into the functional equivalent of [state capitalism](https://en.wikipedia.org/wiki/State_capitalism) as local monopolies completely supplanted all over forms of control in a region - the only twist being that instead of the usual modern case in which a government operates a company, instead a company would operate a government or governments. Fundamentally, the typical cyberpunk future we envision is predicated on and exists entirely within some modern equivalent of the Dark Ages - a massive power vacuum left in the wake of a prior system's collapse. [Answer] Here is how I see the progression: **Corporations Step up their involvement with local Law Enforcement** There are already privately run prisons. Cash strapped municipalities may start outsourcing law enforcement as well, perhaps after a flurry of lawsuits endanger the municipality. This gives the corporation the right to use deadly force, and that is the biggest key. It sets precedent in our legal system, which is very powerful. The carry along effect will also be that the Corporation will now have a very important lever over the local governmental structure. Bribery can also be backed by outright extortion. **Corporations start getting involved with State level politics** this will be more of a financial thing. the goal will be to increase the absolute rights of security on land owned by the corporation. See the above precedent in a corporation using deadly force. At this point we can kiss about half of the bill of rights goodbye. **The Balance of power Shifts in individual states** This is going to start causing some problems at the Federal level, impacting revenues. this weakens the Federal government until our pals the lobbyists offer to bail it out, on terms, of course. **the Federal Government is effectively neutered** at this point the Corporations would have pushed property rights, and what they can do on them to the point that the nation no longer has any sovereignty left at all. Now all we need to do is watch as cybernetic implants become commonplace and wait for magic to emerge once again into the world. I love Shadowrun :) But hey, even if Magic doesn't return, you have a hapy little dystopia to play in [Answer] I look forward to seeing your answer on this subject :) I will attempt to give my two cents on each of the questions posed, but first, I would like to mention that there is a concept that is much like what you are talking about that currently exists (to a lesser degree). It's known as the military industrial complex <https://en.wikipedia.org/wiki/Military%E2%80%93industrial_complex>. This might lead you to some inspiration in this world you're putting together. Basically, the government needs weapons, which in turn pay the corporations to make them, which in turn spend money (lobbyists, and campaign donations) to get more contracts from the government, and this process self perpetuates. If the system is allowed to continue unchecked, I could easily see how the corporations could ultimately gain control. **- What would the relationship between corporation and nation look like?** Basically, the nation has some powers in terms of taxing the people, keeping peace (using corporation weapons of course), and some social laws. Since the corporations effectively 'own' large swaths of the government (through large campaign donations ensuring their candidates win), they allow themselves freedoms from pesky regulations and oversight that might get in their way. It could ultimately lead to the government turning over more power to corporations, and might ultimately lead to them passing all power over. This would likely only come from collusion between a few large corporations, or one very large monopoly company (a la Umbrella from Resident Evil). The lack of regulation would also open the door to criminal organizations and drug rings. **- What would be the most common relationship between employees and corporations look like?** My guess is that since there are only a few large corporations, or a single massive monopoly, the company owns you. There would probably be a few extremely well paid and wealthy people in the bureaucracy, and many poor people. I imagine very middle class people in this society. Education would largely exist to find the cream of the crop for company purposes. **- How would corporations change?** Probably very little over time. Monopolies tend to not change in terms of structure and strategy. Let's look at Motorola, a company that effectively owned the cellular phone market. Smart phones were introduced, and Motorola failed to adapt, and they basically disappeared due to this lack of change. Disruptive technologies could lead to a rise in new corporations, but structural power or the existing large corporations would keep that to a minimum. Imagine if Motorola didn't have antitrust laws: they could have just purchased any disruptive technologies and then developed them themselves, or not at all. **- How would concepts of citizenship, suffrage, and legal representation for individuals and organizations change?** My guess is that there would not be much care for the individual. There might be some basic rights that exist in the shell of a government that is left, but they would largely be symbolic. Organizations would either be largely immune to outside influence, or be able to pay to get rid of the problems (Mafia Style). **- Would there be any semi-stable transitional stages from government rule to full-blown corporate hegemony?** Probably. The transition would likely take a long time, and probably come with a prolonged period of international tension (requiring the purchase of weapons), fear among the people (which leads them to give away rights for safety), and a lack of need to stop monopolies (maybe the company was beloved by the people for some reason, but has since become corrupt as it gained power). **Conclusion** I could easily see how, with some changes in governing in recent history, our society could have become one which was controlled largely by corporations. In fact, you might even argue that is currently *is* controlled largely by corporations. There is simply enough anti-trust activity, and enough varying motivations among companies, that no one is able to gain enough power. Imagine if Standard Oil, U.S. Steel, and other monopolies of the past had colluded to gain more power in the government. It could be pretty different. ]
[Question] [ [![enter image description here](https://i.stack.imgur.com/6u87K.jpg)](https://i.stack.imgur.com/6u87K.jpg) 1. If there's a habitable planet that orbits two suns like the above orbital route, what would possibly occur on that planet? 2. Would it have two yearly seasonal cycle (compare to earth)? 3. Would it be possible that there's some months where there would be no night time on every part of the planet? 4. What other things resulting from the effect on day, night, and seasonal cycles can be experienced if we lived on that planet? [Answer] I'm going to attack this with math. First off, I am not going to make any assumptions about what orbits might be stable. That is something we can check with an orbit simulator like rebound, as I did in [this question](https://worldbuilding.stackexchange.com/questions/23452/can-you-add-a-mini-moon-to-earth/59917#59917). Instead, I will assume there is a stable orbit around two suns of equal mass and luminosity. The orbital profile will be a perfect circle (0 eccentricity orbit) at 1 AU for 3/4 of a revolution around each sun and then a straight line connecting it to the next sun. # Determine the orbits Since this is an ugly piecewise function, and I am solving using a computer, I am defining it in python as such: ``` def f(t): if t < 3/2*pi: return sin(t-pi/4)+sqrt(2), cos(t-pi/4) if t < 3/2 * pi + 2: r = t - 3/2*pi return sqrt(2)/2-r/sqrt(2), -sqrt(2)/2+r/sqrt(2) if t < 3*pi + 2: r = t - 3/2*pi - 2 return sin(pi/4-r)-sqrt(2), cos(pi/4-r) if t < 3*pi + 4: r = t - 3*pi - 2 return sqrt(2)/-2+r/sqrt(2), -sqrt(2)/2 + r/sqrt(2) ``` [![enter image description here](https://i.stack.imgur.com/02Azl.png)](https://i.stack.imgur.com/02Azl.png) The red dots are the two suns. The green dot is our arbitrary time = 0 for the next part; the planet starts moving clockwise around the sun on the right. So far so good, now let us calculate distance from each sun, and plot that as a function of time. # Determine the distance from each sun Since I'm already using the computer, and I know the sun's coordinates, ($-\sqrt{2}, 0$) and ($\sqrt{2}, 0$), I will just calculate numerically using this code: ``` def dist_1(coord): x, y = coord return sqrt((x - sqrt(2))**2 + y**2) def dist_2(coord): x, y = coord return sqrt((x + sqrt(2))**2 + y**2) ``` [![enter image description here](https://i.stack.imgur.com/pg6ot.png)](https://i.stack.imgur.com/pg6ot.png) Where dist\_1 is from the right star and is in blue, and dist\_2 is the left star and is in red. I scaled the time factor to 365 days in a year cause I'm a geocentric kind of dude, but I could use any scale factor. If the planet was moving at the velocity of Earth it would take 1342 days to complete this year, fyi. # Determine enegy recieved Solar energy drops off as 1/r$^2$, so solar energy received from each sun is 0.905 earth units divided by the distance to each sun. The .905 is a scaling factor to ensure that total solar energy recieved by this planet averages to 1 unit. So lets plot those two, and a new black line for the net total solar energy. [![enter image description here](https://i.stack.imgur.com/tzySb.png)](https://i.stack.imgur.com/tzySb.png) # Add seasons Ah, glorious seasons. Lets say we have an earth-like 23.5 degree axial tilt. How will that affect us? Depends on how we orient the tilt. I will arbitrarily declare that the Northern hemisphere is fully tilted towards the two stars when the planet is at the far right point of its orbital trajectory at point ($\sqrt{2}+1$, 0). I calculate the effect of tilt both at the equator and on a point 45 degrees N. At summer solstice (at the point mentioned above) $cos(45-23.5) = 0.930$ of equatorial sunlight, and at winter solstice it will get $cos(45+23.5) = 0.367$ of equatorial sunlight. The angle to either star in our coordinate system is calculated from $\text{arctan}(\frac{y}{x})$ where x and y are the coordinate distances from the star. The cosine of the angle to the sun in radians, which is the proportion of the axial tilt that the planet is currently experiencing, can be expressed as: ``` def angle_1(coord): x, y = coord if x + sqrt(2) < 0: return -1* cos(atan(y/(x+sqrt(2)))) return cos(atan(y/(x+sqrt(2)))) ``` We will multiply that by the axial tilt, add it to the latitude, and calculate the addition or reduction in light energy by season. So here are two graphs showing how the seasons will work. The first graph is for the equator of our planet, compared with earth. The black line is total energy recieved by this planet (earth would be just a straight line at one, assuming a perfectly circular orbit), red is the relative insolation at this planet's equator, and green is relative insolation at our equator. [![enter image description here](https://i.stack.imgur.com/nPrgO.png)](https://i.stack.imgur.com/nPrgO.png) The second graph is the same, except for a point 45 degrees N. So black is the same as above, red is insolation of the other planet, and green is insolation of earth. [![enter image description here](https://i.stack.imgur.com/4V9lW.png)](https://i.stack.imgur.com/4V9lW.png) And remember, I scaled this planet so its day is as long as an Earth day. If, for example, you set the year to be the 1342 earth days for velocity matching, then the first red-hump summer for the other planet would last as long as a summer here on earth. Well hope this is what you were looking for; I have all the code saved if you want me to post any more of it, or throw up a graph for a different latitude. --- Edit: As requested here is a 45 degrees N profile for a 750 day year compared to what Earth would be doing in that approximately 2 year period. [![enter image description here](https://i.stack.imgur.com/wxQT8.png)](https://i.stack.imgur.com/wxQT8.png) As far as the max insolation; the max value for Earth's summer is 0.917, which represents 91.7% of max insolation at the equator. For our mystery planet, the number is 0.830; this is off by a factor of 0.905, which you may recall is the scaling factor by which we had to reduce these other suns to get Earth-like total year-round solar insolation. So that makes sense. On the winter side, however, the numbers are 0.366 for Earth and 0.354 for the other planet. Those should show the same 0.905 ratio. I don't know if this is an error in the code or just somethign I'm not understanding, but I'll take a look. Incidentally, darkest winter at 45 N is not while the planet is between the two stars. This is the coolest time at the equator, the sunlight dips down to about 80% of max; that is like May or July in the mid-latitudes. But at 45 N, you are about equidistant from the two stars, and always getting 'summer' from one of the two. So that mitigates the wintery-ness. Darkest winter is when you are tilted away from both suns on the far left of the orbit plot. [Answer] The biggest shock would be the period in the center of the figure eight where there would be winter--or something near it--on the entire planet. I'm calling the planet Bob. Depending on the tilt of the planet's axis, the seasons would be pretty weird. Let's assume, to make it easy, that the time it would take this planet to revolve one of these suns is 1 earth-year. So one Bob-year would be a bit more than 2 earth-years. For most of the first earth-year, on the left and right loops of the orbit, the seasons would be just like those of earth. But as Bob diverts off a circular orbit, the summer would get colder and colder. By the center of the figure 8, Bob is virtually in a perpetual state of winter all round the surface of the planet. And yes, there would be no night. Assuming that Bob is equidistant from both suns, one sun would be setting as the other one rose on one day of the year. All other days there would be just a bit of complete darkness. But this wouldn't last long. Bob would then get back on track on a circular orbit around the second sun. Let's divide Bob into 2 hemispheres--the North [facing the people looking at the picture] and the South. Let's say the North hemisphere is tilted to the right as you look at the picture. So, beginning on the leftmost point of the orbit, the North follows this pattern: 1. Summer! 2. Fall! 3. Winter! As the days get shorter from Left Sun, Right Sun begins appearing in the sky. 4. More winter! As the days get longer, Left Sun begins to disappear, becoming only a bright star (depending on how far away the town suns are). 5. Spring! 6. Summer! 7. Fall! 8. Winter! 9. Spring! 10. Summer for a bit, then a quick fall, then the all-day-two-sun-epic-winter. 11. Spring! And the South would follow the same pattern, just beginning with the North's #8. [Answer] Well fist off the planet would be almost completely bright when in the center of the two suns (about 2/8ths of the planet would be bathed in a sunset like state), some plants would be different than the ones we see on earth, because most plants on earth have evolved to incorporate the night cycle into the day of plants, but you'd also have to incorporate the times where there is half sunlight. and there would be a difference with animal life, due to the lack of night time. We would have a lot more non nocturnal animals, and the human diet would probably be affected. To sum it up the ecosystem would change drastically due to the change in light distribution in the world, for better or for worse, that is up for you to decide. ]
[Question] [ **In the spirit of Thanksgiving (US) let's tackle a fun one.** I'm defining "intelligent" in this situation as "*at least on par with hunter-gatherer humans, able to communicate*" What natural, environmental pressures would cause turkeys to evolve intelligence, based on the pressures that cause intelligence in the real world, assuming up until this point that turkeys have been developing as normal? **BONUS**: How would this change their morphologies? --- This **is** somewhat on-topic as it provides useful information for worldbuilders seeking to design intelligent avian species. --- Not a dupe of [this question](https://worldbuilding.stackexchange.com/questions/3049/what-could-cause-an-avian-species-to-become-intelligent?rq=1) because I am asking about a **specific species**, not general avians, and I am focused primarily on how the **environment** would change the evolution, not how the morphology would change the species over time - which the other Q does not address. [Answer] # Unnatural selection So the question is: what kind of evolutionary pressure would cause **one particular species** of [an entire order of animals](https://en.wikipedia.org/wiki/Order_(biology)) to develop intelligence — while other species of the same order do not — to the point of surpassing most primates and be second only to that of the genus [Homo](https://en.wikipedia.org/wiki/Homo). Unnatural selection. That would happen only if a more intelligent species bred them selectively, either by actively breeding them or by selectively weeding out the unfit ones. As has been pointed out: turkeys are very [fit](https://en.wikipedia.org/wiki/Fitness_(biology)) as it is. There is no distinguishing feature in turkeys that can make them the target of an evolutionary pressure that will afflict no other fowl. They would need to be targeted by something that weeds out the unintelligent ones, and **only** in turkeys. That will not happen on its own, there needs to be an even more intelligent species that is doing this to them. ...over several millions of years it should be pointed out. [Answer] **We select for it** Every year, the President of the United States pardons a turkey. Right now, we can safely assume it is a randomly chosen turkey, but surely this extra opportunity to breed does not go unnoticed. A turkey that is slightly smarter than the rest would find ways to happen to get picked. Assuming the United States continues to exist for a few million years (no pressure, guys!), intelligence will prosper. Of course, such intelligence could eventually be seen as a threat. Thus I would expect the morphology of a turkey to adjust to be less threatening in appearance. Similar to how the kitten is cute and innocent and lovable, but the \*#(@# cat knocks over the \*@#$$# water glass every @\*(#$!$@ time! *ahem. Sorry about that.* Accordingly, I would expect their morphology to change to something akin to a kitten. We love big eyes, so perhaps: [![Turkey!](https://i.stack.imgur.com/nYDOp.png)](https://i.stack.imgur.com/nYDOp.png) [Answer] Well, wild turkeys are actually very fit. I could imagine that through natural selection, that a turkey might evolve to have some hunter traits, the reason being is that given two turkeys, one who can only forage, and another turkey who not only can forage, but has learned to take advantage of a situation, and developed a taste for flesh, the later will be more successful ultimately, because it is more versatile. The ability to "Imagine the future" is what leads the turkey to sentience. Imagination is the essence of planning and strategy, fear and hope. A turkey who could learn to take advantage of situation, can "imagine" how to create the situation, thus making sentient turkeys who hunt. The making of weapons would come next, and would surely be interesting because of the lack of hands. Those weapons would be shaped by beaks and talons and designed to hunt smaller animals. But occasionally, turkeys might build traps for other larger animals that might be predators of the turkey tribes. Natural selection would favor the faster stronger turkey, and I could imagine the turkey wing becoming stronger over time, as those with weak wings might break during the hunt and become lame and die. Eventually, the turkey wing would be strong enough to break human bone and yet remain light enough for flight. [Answer] Human species evolve from primates, and we know that some species of primates already knows how to use a simple tools like sticks and stones. Primates are also knows hierarchy, and develop a strategy a traits that usually seen on hunter type animals. All of these traits are what we can suspect as some of the foundations of our evolution, and even among all that share this traits, we can say until know that we don't know any other species like ours. Turkeys on the other hand didn't share these traits. So to make them to walk our path of evolutionary process do develop our standard of what we called intelligence and able to communicate will take them to unnatural evolutionary process. And I provide two alternatives for them: 1. Is to make us to be more supreme and more advance species first. If we can develop our species first to a proven way to make our species intelligent level leap. Maybe we can implement them to a turkey. 2. To throw the turkeys to another world where they need to develop organisational skill, and use tools to survive. Maybe a world where they need to eat bugs and worms that are tricky to catch, that on scarcity they can hunt for it with their beaks but to thrive they need to develop a tools. A plus if their predator is present to give them a sense of danger that would kick in the evolutionary process. And when its happen, we wouldn't seen them as a turkey anymore. They wouldn't have their useless but delicious wing anymore. Maybe they would look like some crooked trolls with a beak, and governing a worm farm. [Answer] To become naturally intelligent, turkeys would need to go along many of the same pathways as other intelligent species on Earth. Hunting or being omnivorous would seem to be a good fist step, since they not only can access more and different sources of food than the competition, but also would need to develop some intelligence thunk prey and find and exploit different food sources. Most intelligent animals on Earth also are social, living and working together in groupings like troops, packs and pods. Being social and cooperative seems to be important in developing sophisticated communications between members which leads to language. A flock of photo intelligent turkeys would resemble a troop of baboons, perhaps, more than a standard flock of birds. As for morphology, the turkey will loose a lot of its bird like features and develop in ways which support both the new lifestyle and a brain large enough to support intelligence. The "face" will become more like that of a raptor with forward facing eyes and other adaptations to support hunting (a serrated beak, perhaps) or omnivorous behaviour (a beak sharp enough to cut chunks of meat from prey but also strong enough to crack nuts or seed pods). This evolution was simulated with a species of dinosaur called the Troodon, which would already have been much smarter than a turkey to start with. A hypothetical intelligent descendant of the Troodon is illustrated below: [![enter image description here](https://i.stack.imgur.com/TcKcO.jpg)](https://i.stack.imgur.com/TcKcO.jpg) We now know that most dinosaurs were covered in protofeathers, and the Troodon was theropod (the ancestor of birds), so would have likely retained this feature for warmth and sexual display. It is also quite possible that the evolved turkey would be more bird like than this thought experiment, for example retaining a longer tail for balance but having wings become vestigial and manipulating objects with the feet instead. [![enter image description here](https://i.stack.imgur.com/00sn9.jpg)](https://i.stack.imgur.com/00sn9.jpg) *Reconstruction of a Troodon. An intelligent Troodon might have a larger head and highly developed feet* A highly intelligent turkey would not be very appealing to the human eye, and the Ancestors would certainly have either tried to domesticate them in the distant past (like they did with wolves as the ancestors to dogs), or hunted them to extinction as an existential threat. ]
[Question] [ My name is George. I am the true creator of peanut butter. Since my discovery, I fell into a time vortex that landed me in 2014 where I have found that my old rival has taken credit for my idea. I've spent the last 2 years trying to figure out a way to bring justice to my name, and though I have found myself in the future, most of your society still doesn't believe in time travel. Does anyone have any ideas on how to prove this kind of intellectual property (includes patents and trade marks) infringement? [Answer] First off, you are talking about an industrial product or process (making peanut butter), which is covered by patents, not copyrights or trademarks. (Copyrights are for published books, musical works, movies and similar things, while trademarks are for the identifiers of products, such as trade names. "Hook and Loop fasteners" is a term used these days since Velcro is the actual trademarked name of the product. Unless Velcro actually made the stuff, you can't refer to it as "Velcro"). That out of the way, what you need is some proof that: a. You are, in fact the inventor of peanut butter b. Your patent exists prior to the claimed date of invention c. Your patent has not expired Proof that you are the inventor of peanut butter is going to be difficult. Somehow you are going to have to produce laboratory notebooks, patent applications, correspondence with investors or other parties or other documentation demonstrating your prior claim. These documents need to be authenticated somehow to demonstrate they are not clever forgeries (and there is the additional problem that you are obviously not 200 years old or however old you would be if you were the inventor of peanut butter). If you are working on behalf of the inventor of peanut butter (you tell everyone you are a grandchild or nephew of the inventor), then you at least avoid that problem. Lots of people *invented* things, but credit goes to the person who filed the patent first (and had the patent accepted). Unless you are a polymath like Leonardo da Vinci, who's detailed drawings anticipated tanks, flying machines, submarines, diving suits and so on over 500 years prior to the large scale adoption of these devices, most people are going to dismiss you as a crank, or at the very least as a poor loser who submitted the application second. (Note in the case of Leonardo, he at least fulfills condition one. *No one* disputes his primacy in these fields). Finally, patents expire after a set time (traditionally it was 20 years but can vary with the country). You may be able to document your claim, but if the patent expiry has passed, you will be out of luck claiming any royalties for this. For the record, most people agree that [Dr. John Harvey Kellogg](http://infogalactic.com/info/John_Harvey_Kellogg) invented peanut butter in its modern form. Indeed, the National Peanut Board states that Kellogg received a patent in 1896. Good luck overturning that claim.... Edit to add link to Kellogg's biographical information. [Answer] You'd need some kind of documentation of the discovery that didn't travel through time with you. It sounds as though, for some inexplicable reason, you didn't bother taking any precautions for normal, forseeable events like storms, floods, and rips in the space/time continuum, so I doubt you have a safe deposit box at a bank or similar. You might be able to find your old safe with your original recipe and notes in it, if your rival didn't use his treacherous minions to track it down while he twirled his mustache; these would be ideal. You may also be able to find something in a bureaucratic organization's archives. Lawyers, for example, could well have kept very old correspondence. Even if you can prove your claim, however, don't count on easy riches. The Peanut Butter Cabal is powerful, and you'd have to prove not only that you invented it, but that you are the same person as the one in the documents. Since peanut butter was patented in 1884, and you have no doubt been declared legally dead in the mean time, you're not likely to get anyone to accept you as the true inventor of peanut butter. Also, even if you prove your case, it's likely to get you no more than a quiet mention in the history books. Look up the case of Antonio Meucci, who claimed to have invented the telephone. His work was done long before Alexander Graham Bell's 'invention', but he was unable to afford the fee to maintain his copyright on the invention. When it lapsed, Bell snatched it up and filed his own patent. Even today, after the US Congress has passed a resolution effectively recognizing Meucci as the inventor of the telephone, his name is little more than a footnote in history. ]