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[Question] [ > > Prima walked out to the observatory's main deck. There, as she had expected, Secunda was sitting in the grass, looking up at the stars. > > > "Pretty, isn't it?" said Secunda, as she craned her neck backwards to look at her sister. "You can see everything tonight." > > > "Everything?" replied Prima. Slowly wading through the grass, she glanced up and was instantly spellbound by the celestial garden of steady pinpricks of light, white and yellow and blue and red, smeared into blooming radiant petals by the thick observatory dome. > > > "Everything," whispered Secunda. "Well," she added, "except for Terra, I suppose." She stood, stretched, sighed, and turned to her starry-eyed sister. "Hey," she said, "I want you to follow me. There's a telescope over there that has a lens outside the dome. I bet we can see Mars from here." > > > Prima frowned slightly. "Really? Where is Mars from here, anyway?" > > > --- Suppose that Prima and Secunda are from our Earth, only a few centuries in the future. **Could Mars be visible from Luna's night sky? What else would be visible? Would it be normal for Terra to not appear at night?** I know that, at a minimum, Luna's lack of atmosphere would mean that stars don't twinkle. I suspect that the Milky Way is apparent sometimes, and that the sky's view changes as Terra orbits Sol, so that the seasonal constellations are either similar or analogous in scheduling. --- Edit: Thank you to all contributors. I've tried to upvote every helpful response, and will be thinking of tidal locking and thin atmosphere quite a bit now. I need the practice, so have some more: > > "Got it! Aw, Jupiter's not as big as I had hoped," whined Secunda, pulling her face away from the goggles. The optical tube trailing the goggles, large and padded, made a sympathetic groan as it sagged slightly. > > > "What‽ No way, let me see already," Prima said as she groped for the goggles in her sister's hands. > > > "Okay," said Secunda. Prima's hands met hers on the goggles. She stepped towards Prima, and helped orient the optical tube to a position approaching stability. Prima pressed her face to the goggles, while Secunda giggled quietly. > > > Prima frowned, then jerked up from the goggles and glared at her sister. "You cheat! That's a photograph, isn't it? That's not real!" she protested, before breaking out into giggles herself. "You're such a joker sometimes," she snorted between laughs. > > > Secunda frowned. "No, I didn't," she started, then gripped the goggles harder and pushed them back into her sister's face. "Look carefully. Do you see it?" > > > Prima stared closely at the beautiful storm-ridden gaseous orb for a few moments, then gasped, "It's…moving? Crawling? It's alive! I can only barely see it, but it's moving somehow. Rotating?" > > > Both sisters were quiet for a moment. Then Secunda poked Prima. "C'mon, it's my turn again!" she said. > > > [Answer] At this moment? According to NASA/JPL and their simulator at <http://space.jpl.nasa.gov/> , something like [![mars from moon](https://i.stack.imgur.com/Kn85f.jpg)](https://i.stack.imgur.com/Kn85f.jpg) [Answer] Because the moon is relatively close to Earth the night sky will be relatively similar. The two big differences are the lack of an atmosphere and a big planet in the sky instead of a moon. Whether the earth is visible on the moon is dependant on where on the moon you are. The moon is tidally locked to the Earth so the same side will always be facing the Earth. From the near side of the moon the [earth is always visible](https://en.wikipedia.org/wiki/File:NASA-Apollo8-Dec24-Earthrise.jpg). Without an atmosphere there will be less light pollution and twinkling. [Answer] Could Mars be visible from Luna’s night sky? Yes depending on the time of year and the hour of the day, as on earth. Would it be normal for Terra to appear at night? From the far side of Luna no never, from the near side of Luna yes always as Luna is tidally locked to Terra it rotates once per month so always shows the same face to Terra. [Answer] **Generally speaking, you can see the same stars from the moon as you can from the Earth, but there are some issues:** 1) The moon is [tidal locked](https://en.wikipedia.org/wiki/Tidal_locking) to the earth, which means the same face ***always*** faces the earth. If you are on the far side of the moon, you will always see stars in the same manner as if you were standing on the Earth. If you are on the near side of the moon, you will always be looking past the Earth, which means the Earth will block almost everything (if not everything) in the sky. Also, if you are on the far side of the moon, you will experience a long day ([~13.5 days](https://www.space.com/24871-does-the-moon-rotate.html)), and a long night (also ~13.5 days). If you live on the near-side of the moon, you will experience those same long days and nights, but you will also have periods of reflected light from the earth (full moon) and eclipsed light from the earth (new moon). You need only look at a [lunar phases](https://en.wikipedia.org/wiki/Lunar_phase) to see what "daylight" is on the near face. > > This is a big deal as it means a substantial number of stars won't be visible either because the sun is in your eyes or the Earth is blocking the view. > > > 2) The moon's orbit is not on the same orbital plane as the Earth (see pic, below). This means the stars visible on Earth at a particular time won't be the same stars visible to the moon at that same time. (What do I mean by this? If it were the middle of the night and the moon were directly overhead, then someone standing on the Earth's equator will see a slightly different star field than someone standing on the moon's equator.) [![enter image description here](https://i.stack.imgur.com/GCQH3.jpg)](https://i.stack.imgur.com/GCQH3.jpg) 3) The moon wobbles something awful (see pic below and [relevant discussion on Astronomy.SE](https://astronomy.stackexchange.com/questions/9937/shouldnt-all-moon-orbits-be-inherently-unstable)). This will also affect what stars are visible at a given moment compared to the same moment on Earth. [![enter image description here](https://i.stack.imgur.com/8mFbX.png)](https://i.stack.imgur.com/8mFbX.png) ]
[Question] [ Assume Humanity was really wrecked by some malignant force, and a group managed to escape and find a habitable planet and 'settle' it. They weren't able to bring along much in the way of advanced technology, but they were able to bring along relevant knowledge. So, while they reverted to the 'Middle Ages' as far as basic technology goes, they can take care of things like medicine and nutrition much better. They're then able to, over time, re-build up to a WWII/1950s era technology level. The world they found is very early in its development cycle. There's plenty of fish in the sea, but no creatures have made their way onto land yet. ***Clarifications & Updates*** The planet is assumed to have plant life (Otherwise it is far too uninhabitable even if technically livable). It is noted below that trees developed much later, so I am curious as to what could replace them (even if it is handwaving trees into existance). Initial population size is a few dozen thousand - perhaps 40 to 75. They arrived in a small fleet of vessels, with small craft for planetary transportation. There is no method of refueling these craft, and the large craft are too large to land. I am presuming they can use these ships for a few dozen years to set things up. The craft have some manufacturing capabilities (IE, printing books), but were not designed or supplied for a long term mission. They function long enough to establish a foothold, gather some images for maps, do some limited surveys, etc. What sort of impact would this have on a (re-)developing civilization? From what I've read and seen, there would still be things like coal and oil (Although in lower quantities), but beyond that I have no idea on what sort of repercussions there would be for civilization. [Answer] Assuming they have been there for some time, slavery would prevail, humans would take the place of draught animals for labour etc,. This has played out enough times in different parts of our World's history in both large and small economies without suitable animals for labouring purposes. Inca and the Pacific Islands spring to mind, but pretty much everywhere at some time or other. Important things to everyday life would be problematic, leather, sinew, bone etc,. there is an obvious source but it would make a distasteful story. Probably large economies would all be coastal and industry and some technology would be based on sea life. Living inland would be a big problem, nothing produced that would be worth trading such as skins or furs, so marginalised communities would inhabit the inland areas. With perhaps some specialised communities engaged in mining ores or something similar. [Answer] # Pessimistic Scenario I am going to be pessimistic and suggest that your colonists will die unless their new home is very much Earth-like and much closer to our geological timeline than you suggest. It seems that your world is akin to Earth of [the Cambrian period](https://www.wikiwand.com/en/Cambrian) (541–485.4 mln years ago) since you say that land is still uninhabited. And it creates a huge number of problems that cannot be solved with Medieval technologies. ## Food Production 'No land creatures' does not mean 'no life'. But it suggests that there are no higher plants. Most likely you have lichens and bacterial mats. These are good for oxygen, but not so good for the soil. There is some research suggesting that plant life developed much earlier than the Cambrian period, [about 700-1300 mln years ago](http://science.psu.edu/news-and-events/2001-news/Hedges8-2001.htm). Still, it took a long time for soils to emerge. They also require the presence of incests, worms, and other animal life. [The first soils similar to ours developed only about 350 mln years ago after the land was filled with all kinds of animals. Grasslands did not appear till 65 mln years ago.](http://www.bbc.com/earth/story/20151205-one-amazing-substance-allowed-life-to-thrive-on-land) Even if you manage to bring seeds, you will not be able to grow crops. Available soils are unable to support root systems and do not have nutrients required for contemporary crop plants. ## Building Materials No soils supporting higher plants also results in absence of building materials. Thorne mentioned timber, but you might not have even ferns and mosses. So, you will be restricted to mud, clay, and stone. Building even a simple shelter will be a big undertaking. ## Tools Civilisation and technology mean tools. While your colonists will be able to scavenge and repurpose something from a ship, they need to be able to produce their own tools. Unfortunately, the Cambrian setup limits them to stone. Moreover, it is not even possible to produce a simple axe: there are no handles. Metal and bone are not an option since you cannot smelt ores and forge metals and vertebrates with suitable bones do not exist. ## Mobile Power Sources Animals are not so good sources of food (need too much food to grow or too hard to hunt), but they are delicious and most importantly they are great for powering your technology. If humans are the only animals available as power sources the productivity is very low and specialisation necessary for a successful civilisation building is hardly possible. ## Fuels ### Oil Good news -- oil will be in a process of creation. Bad news -- you, probably, have to wait several dozens of millions of years before it is usable. ### Coal You might luck out and find a little bit of coal formed from ancient algae. But [most of the coal originates from flooded forest](https://www.wikiwand.com/en/Coal#/Formation) and your planet is not there yet. ### Natural Gas You might get luckier with natural gas, especially if at least some part of it is [not biogenic in origin](https://link.springer.com/article/10.1007/s13202-016-0271-5). ### Biofuels [Algae fuel](https://www.wikiwand.com/en/Algae_fuel) is your best bet. Your planet is exceptionally good at nurturing all kinds of algae. BUT you most likely need an industrial level of technology to extract fuel from biomass. ## Biology There is no guarantee whatsoever that the planet is habitable without terraforming. While building blocks of life might be the same they are not necessarily arranged in the exactly terrestrial way. We tend to think of ourselves as highly adaptable species. And this is quite true but in Earth conditions. The problem is that parameters of our survivability are [very narrow](https://www.livescience.com/34128-limits-human-survival.html). Slight differences in temperatures, atmosphere composition, and humidity may render a planet unlivable without advanced technologies and life-support systems. When it comes to food sources the situation is even worse. Humans might be unable to digest local food. They might be allergic to local flora and fauna. Plants and animals may accumulate toxic quantities of some substances. There is also no guarantee that terrestrial plants and animals will survive. Modern crops are very vulnerable. You will unlikely to have pests unless some algae and fungi decide they like to chew on your wheat, but weather and soil conditions might turn to be very unfavourable. Lack of nutrients, strange weather patterns, flooding or droughts... just one of them is enough to put your settlement to the brink of extinction due to crop failure. Similar reasoning goes for animal husbandry... --- I am sure there are more possible reasons for the colony to fail. But even this is enough. Let's move to Paradise. # Optimistic Version Your colonists are extremely lucky and end up on Earth 2.0. The soil is good, the marine life is digestible, and terrestrial immune systems are dealing with the local environment just fine. We will also assume that the climate is nice: not too warm, not too cold; the winters are mild and short; there are no hurricanes, tornadoes, or typhoons. Something like a Mediterranean climate on Earth. You will have a long growing season suitable for many agricultural plants. You also will not need to invent and erect architectural marvels to protect from elements. I hope I am close enough to an Eden world. But even Paradises have problems. You will have exactly the same problems with power, building materials, and tools as in a pessimistic scenario. So, there is a high probability that your colonists go back to stone age agriculture and fishing instead of rebuilding civilisation. Even if your colonists brought enough tools and specialists to jump-start a Medieval-type community and make it sustainable, including the production of necessary tools, animals, foodstuffs, textiles, and so on, it does not guarantee quick technological progress. ## Population Size The more advanced your civilisation, the more people you need to support it. The only exception is fully robotized society. So, you need some minimum population to start and a high population increase to progress technologically fast (given that you already have a technology chart). A rather small Medieval town had a population of about 10 000 people. This allows for a self-sustainable community given that all raw materials can be gathered nearby. Big cities had populations of hundreds of thousands people. Check this [link](http://www222.pair.com/sjohn/blueroom/demog.htm) for some other interesting facts. In 1950, USA population was [about 150 mln people](https://www.wikiwand.com/en/1950_United_States_Census). The economy was virtually self-sustainable. There is an evidence that [agriculture was over productive, but it helped to absorb the shock of the 1950s Drought](http://www.sciencedirect.com/science/article/pii/S2212094715300530). At the time the USA was also a world leader in terms of science and technology. So, I suppose, it is a good point of reference. So, your problem is to progress from 10 000 people to dozens of millions in the shortest time possible. Time is important here due to problems associated with knowledge. ## Knowledge Bringing knowledge and keeping it through generations is not the same thing. ### Medium If your colonists do not have hard copies of their knowledge and cannot establish an effective educational system the majority of information will be lost. Your colonists have to store knowledge in some form that is accessible to their Medieval level descendants but in volumes useful for higher technological levels. You do not want them to reinvent electricity and bicycles. You want them to build from blueprints ASAP. Stone tablets are known to be one of the most reliable methods of information storage. But they are heavy and take too much space if you want to fit a couple of contemporary textbooks. You might want something like [paper vellum](https://www.wikiwand.com/en/Vellum#/Paper_vellum). For newly accumulated knowledge your colonists will need a way to write it down. Unfortunately, stone and sun-baked clay tablets can be the only available to them media (the tree problem strikes again). ### Preservation and Passing onto Next Generations 10 000 people seem like a lot of people but their cumulative knowledge is smaller than knowledge available in the 1950s. Moreover, much of what they know is completely irrelevant to their current situation. In addition, without an extensive educational and knowledge systems that we have now (or even in the 1950s) passing this knowledge onto descendants would be problematic. And of course, the first planet-born generation will be more interested in learning how to farm than a theory of aircraft building (no resources to build one). There is nothing can be done about resulting loss of immediately accessible knowledge. However, if you establish compulsory school education, keep 100% literacy, encourage scholarship, and preserve scientific method and germ theory, you might significantly shorten your Dark Ages. Do not forget to establish some kind of a scientific council and give them THE Civilisation Development Plan. Too bad it is hard to combine with religion... but if you can, you could promise eternal punishment to those heretics who refuse to learn professions necessary for fulfilling The Plan. ## Other Things You can expect a loss of purpose, mutinies, riots, peasant riots, famines, pandemics, etc. The lower your population the more risks all those pose. It is also possible that your colony will start a global climate change by bringing invasive plants. They will suck too much CO2 from the atmosphere and trigger an ice age... If it is the case start polluting ASAP. ## More Other Things The first generation will go through 'survival syndrome' and PTSD. Just it makes a great story. [Answer] A Middle-Age level society without animal is simply impossible: animals (cows, horses, mules, etc.) where the only available power sources in those times which could be used for easing the work of men. Same goes for food: no animals means basically no or flimsy proteins income in their diet. Moreover, if there are no creatures on the dry land, it can very well be that this is because the dry land itself is not life-friendly, i.e. not enough oxygen in the atmosphere to build an ozone layer to shield UV light. So, not exactly the best place to thrive. [Answer] Since the starting conditions for colonists vastly improved, I am going to write another answer. Basic assumptions: * colonists can grow crops in local soil; * local flora and fauna are not toxic to colonists; * the climate of the planet is similar to Earth; * colonists, except spacecraft crew, are not trained for space travel and exploration; * colonists are random people from a developed world (the latter is important); * colonists brought vast knowledge databases with them, including technical blueprints; * there is no magic genetic replication/synthesis machine; * the landing was successful, the majority of craft is intact, but cannot go back to space; * the land life developed insects and worms (they are necessary for plant pollination and modern soil development); * there are no birds, reptiles, or mammals; * seas are full of life, including early fishes ## Skip the Middle Ages Your colonists cannot and should not go back to the Middle Ages technology since it relies heavily on animals and wood. You have neither. With **40-75 thousand** people (although a more specific number would be better) and functioning landing craft you can go straight to electricity-powered technologies. You can use your landing ships as shelter and power generator for the first couple of months. Your craft cannot be power-dead since you mention limited manufacturing capabilities and map/resources surveys. Using one of the vessels build a hydroelectric power plant. A nearby fast-flow river or better a waterfall would be ideal. You are not up to building dams unless your limited supplies include some construction equipment and materials. ## Immediate Population Census and Re-education Centres It sounds like your colonists are refugees. While some of them were, probably, selected for this mission, some just managed to hop in. Conduct a population survey (better while still in transit to the planet): * standard demographics (age, sex, marital status, etc.); * education and practical experience (basically, education and work history plus hobbies); * medical history (even though your population is big enough to avoid inbreeding and other unpleasant consequences of the population bottleneck, you have to be prepared to deal with a heart attack of your senior mechanic). Establish a system of triage to divide people according to immediate survival needs: 1. useful skills (engineering, city planning, medicine, electricity, biology, geology, agriculture, etc.); 2. semi-useful skills (psychology, sociology, law, computer programming, etc.); 3. useless skills (finance managing, banking, hospitality services, etc.). Developed countries have service economies, so the majority of your colonists will have skills not so useful for survival or rebuilding the civilisation. Do not dismiss those skills, though. A hospitality services specialist might not know about catching fish, but they will have insights for setting up comfortable accommodations at a later time. Setup education and apprenticeship programmes. Some can be started back on a ship, some will have to wait till landing. Teach as many people as possible to produce food. Train electricians and electrical engineers. Start training children and teenagers as research aids for scientists (science involves a lot of data sorting, keeping, and entering; your scientists would appreciate all help they can get with this). ## Food Production Ration your food from the very beginning. Lock it if needed. After landing start food production immediately. Amadeus has some great suggestions for fishing. Starting agriculture might be challenging, but it is absolutely necessary if you want to rebuild your civilisation. You can go with conventional farming using [crop rotation techniques](https://www.wikiwand.com/en/Crop_rotation), but it is a backbreaking work even with animals. You will also depend on weather a lot. Since you have a lot of knowledge and at least some technology available, you might be better off repurposing some of your equipment for vertical and greenhouse farming and algae breeding. Hydroponics and aeroponics might be within your grasp depending on your original spaceship. If it was used there, you might scavenge the system before landing. If you cannot afford those, go with soil but in a greenhouse use materials from your ship. This will give you better yields. No matter what kind of farming you decide to do, make sure to start using electricity as soon as possible: lights, machines, heating, etc. If you use the medieval farming approach you might end with almost 90% of population farming. And you need those people to rebuild the civilisation. ## Energy Electricity and algae fuels are your best options. Start figuring out how to produce them ASAP. Electricity might be easier since any biofuel requires an industry to refine it. When deciding how to recycle your ships give priority to building an electric grid. It will help to rebuild the industry. ## Mining Mining, smithing, and such should be your #3 on a list of priorities. You have to replace tools and manufacture new ones. Moreover, since your world does not have wood or bone and you cannot produce plastics, metals will be your main material for years to come. You will not be able to power your furnaces with wood. You might not have coal. But you can and should use electricity. Start small, grow bigger only when you need to increase production or have electricity surplus. ## Glass Another important industry that has to be established ASAP is glass manufacturing. Glass is great for your greenhouses. It is also important for keeping science going. ## Pottery and Clay Without wood and plastics, clay will be your best friend. You can make bricks to build buildings (but I believe concrete is a much better option). But most importantly, you can make pottery to store your food. ## Concrete Busy your colonists with the invention of concrete. It is a very versatile building material. You can construct roads, dwellings, supports, etc. Concrete manufacturing will be the most important step in building modern infrastructure. You might consider working on some glazes and paints. Plain concrete is boring and concrete cities are bad for mental health. Splashes of colour and variety of forms in city architecture help to decrease depression and suicide rates. They also provide better stimulation for little ones. ## Timber Did you bring tree seeds? If you did, it might be a good idea to start growing a forest. It will not be useful for your colonists, but their descendants centuries later might appreciate your effort. You might not be able to find anything that can be used as timber in your world. Reeds and bamboo-like species still can be used for building. Maybe your world has them. You can start selection work on bamboos so they have more wood-like properties. If you have access to DNA sequencing equipment selection will go much faster. ## Social Aspects Your population is quite big. You cannot expect that it will just function. You will have to establish some form of government, law, and education systems right from the beginning. If the majority are civilians a military or totalitarian/authoritarian approach might not work. Although, it would be the most effective for getting things done. Perhaps, you can do with representative democracy, but keep the bureaucracy to a minimum. You need all hands you can get to do the manual work, at least in the first decade. You will also need laws. There will be crime. You have to decide how to deal with it. Harsh punishments reduce petty crimes but increase violent crime (especially murders). Can you afford jails? Are you going to adopt forced labour? What is your stance on capital punishment? An educational system is very important for rebuilding a civilisation. You can try to recreate our system or go with other approaches. I think that compulsory early education in combination with apprenticeships could be a good approach in your setting. However, make sure that you do not have guilds. Children should be free to choose their occupations and information must be free. Your population should be encouraged to grow. Yet, at the same time, you have to have 100% employment. Set up daycare centres, involve elders, encourage parents to bring children to work. If you are keeping a traditional family structure, make sure that fathers are active participants in child-rearing. You might also consider 'communalizing' house chores. That's where your hospitality service specialists come in handy. Set up communal kitchens, cleaning and laundry chores rotation, etc. Make community services mandatory for all men and women regardless of their professions, age, and social standing. Involve children from an early age. You will have insurgents. There will be people who decide that they can do better on their own. Let small groups go, but do not allow your population to split into 2-3 big camps. You need all those people to work together. It might actually be an interesting plot development if a significant chunk of the population (about 10 000 people) decides to resettle elsewhere and truly start a medieval society. Then you can have two different civilisations on the same planet. You can even purge the records of the Big Insurgency, so once they meet they are very surprised. ## Economy You will have to start with socialism and communal property. There is no other way because you will be working on huge projects from the start. You cannot allow economic interests and private property to interfere with industrialisation. Your colony might evolve into something else later. But you should keep it socialistic as long as possible, at least till you achieve about 20th century self-sustainable level of industry and population of millions. Your human resources are very limited. Every individual should have the best chance at realising their potential. They should have free access to knowledge, medicine, and daily necessities. Once you are out of rations you might consider universal basic income. ## Arts, Crafts and Culture Your colony will develop a unique culture. Most likely it will be a mix of cultures of original colonists adapted to current conditions. In order to specify features of this new culture you need to answer several questions: * Does the majority of your colonists belong to the same culture? (People from the same culture have easier time working together, but are more constrained when it comes to finding original solutions to existing problems) * If it was one culture, which one was it? (US culture is very different from Chinese; Chinese colonists will be more likely to setup a system that benefits community first, while Americans might demand more privacy and personal freedoms) * Are there any minorities of any kind and how are they treated? * Is there some vision of an 'ideal' society? * Is there any specific social engineering? All of these will greatly affect attitudes, expectations, and cultural practices of your people. After a century on this planet, the society will be different and many cultural references will become obsolete. In a world with no forests 'Don't see wood behind the trees' makes no sense. You need to come up with new references and sayings. Arts and crafts will not disappear completely, but likely to experience a decline. Woodworking, woodcarving, and such will disappear completely. Painting, pottery, stone sculpture, metalwork will flourish. The architecture will start as very utilitarian. However, as the colony becomes more and more self-sufficient and even wealthy buildings can become more elaborate and richly decorated. Due to the lack of resources, people might switch back to living on a floor as in Japan. Without wood, it will be hard to make tables and chairs. Rugs and hammocks might replace furniture we are used to now. You will have to come up with new musical instruments if you want music. Although, your composers can use synthesised Earthen instruments if they retain access to knowledge databases. Fashions will change considerably due to the lack of traditional materials. In this new world, you will have no wool, leather, silk, or contemporary synthetic fibres. But you might find some interesting replacements (spider silk? fish skin?). There might be some customs and traditions associated with landing and rebuilding. You can also have some remnants of old world like Christmass. ## Science Expect a lot of discoveries in fields of marine biology and various bacteria. Your colonists will be in search of replacements for plastics and fuels. They will be researching bacteria a lot since we know that they can do a lot of useful things. Also, think about all the small things that the first generation of colonists will be missing from Earth. I bet they will come up with some substitutes for alcohol or/and recreational drugs within the first year. [Answer] The worse thing is that this early in cycle is that trees wouldn't exist yet meaning no wood. Timber is an easy building material and fuel source. Land dwelling animals arrived around 400 million years ago but trees didn't develop until another 40 million years later. Technology can always be rebuilt. The most important things to a settler would be the seed banks. [Answer] ***edit:*** The OP allows plants, but no trees. Actually this is reasonable; woody trunks may well be an evolutionary response to predation and trampling by early animals; the fact that many trees can survive collision with a car could be a result of withstanding collisions with dinosaurs; or attempts by dinosaurs to eat them. Medieval technology (and earlier, some from thousands of years ago) is capable of forging steel as good as modern steel, glasses and fine polished lenses, refining metals (like gold, silver, copper, tin) and forming alloys, casting them into shapes. The OP allows libraries of ***relevant knowledge***, we will rely upon. For fuel, we can gather plants and leaves and let them dry; starting a fire should be no problem. With 40,000 people, we will have plenty of 1%ers: Not in the wealth department, but the knowledge departments: biology, engineering, human medical, medicine, physics, architecture, astronomy, geologists, mining, metallurgy, refinement, etc. We have to figure out what is edible and what is not. On Earth we used a lot of animal power for farming. Getting organized we will have to use human power. Eventually we need engines, and what can be built easily using the medieval tech is steam engines. [The first steam engine](https://www.livescience.com/44186-who-invented-the-steam-engine.html) was invented by Thomas Savery in 1698, and in fact a proof of concept of using steam to create rotary motion (as the article shows) was built 1600 years earlier, in Greece. So everything needed by a steam engine is theoretically available to us, in time. We can mine, and the basics of how to build a steam engine should be in our library and known amongst our population: Given a population of 40,000 we have a 99.998% chance of *somebody* knowing anything we need to know (computed as $0.5^{\frac{1}{40,000}}$); an even better chance if we include our library, so we just need to get our knowledge map in order (the types of things that specific people are expert in). The Steam engine allows for turning any kind of plant life into energy for machines to plow fields, dig mines, break rocks, etc. We have had [steam powered cars,](https://en.wikipedia.org/wiki/Steam_car) and of course trains. I expect this society to leap pretty quickly from medieval to early industrial, late 1800's on Earth, perhaps even early 1900's: They know what electricity can do! A great deal of technological advancement comes from ideas, and just as teaching is often a very fast recapitulation of key ideas that advance something, these settlers already have the key ideas, they brought them along. For example, nobody has to come up with the idea of the car, truck or steam locomotive, or convince anybody that a locomotive on rails could transport thousands of tons. They may have to work out some details, but all of them know this is both possible and valuable and ***will work.*** Nobody has to invent the tractor, thresher, or the idea of industrial farming on a vast scale. Nobody has to invent the lumber mill or casting iron. Nobody has to be the first to try using steel beams to build tall buildings. Aircraft do not start as a curiosity that nobody really knows what to do with; nobody doubts plastics (or something similar) and rubber can be made from plants and everybody knows what they are good for, nobody doubts the use or existence of tough light ceramics or metal foams and their utility. Heck, nobody has to invent algebra, calculus, physics and mechanical engineering, or medicine for that matter, or the hundreds of crucial and game changing ideas that brought us from the middle ages to the modern age. (The idea of germs, extreme sanitation, and doctors simply washing their hands before and after treating patients or doing surgery has saved literally millions of lives, as has the simple idea of boiling water before drinking it or using it on an open wound). Given 40,000 people drawn at random, anything known on earth by 1 in a 1000 people should be known by a few dozen in this group. Of course the biggest cultural change is going to be a seafood and vegetable society. They need to feed themselves fast! I presume the fish are edible; at least edible if cooked. The best fast tech I know of for catching Earthly ocean fish without wood are stone fish traps. Remnants of some of these have been found from over 2000 years ago; it is not a new idea. They do need to be located in chosen places based on current and tides, they do not necessarily just work anywhere. There is a tidal trap: The idea is to find a place where high tide is several feet, and fish come to feed in waters too shallow to reach during low tide. Build a semi-circular loose stone fence (meaning don't fill in the gaps with mud), of a specific height, tight enough that larger fish cannot swim through it. Place it just before the water line at low tide: You want fish to be able to swim over (or around) your fence at high tide, but be stranded on the shoe by it at low tide. At low tide the water drains out, between the rocks, and you go collect your fish, using a rock to kill them. There are current traps: On earth at least, fish do not reverse course to get out of a trap, and they don't seem to have any memory of how they got someplace. So the current trap is built as a fence (using rocks again), in the shape of a 'comma'. Fish swim with the current along the shore line; some end up on the shore side of this fence (at the tail of the comma). They won't reverse course to get to the other side. The fence guides them into a circle; the ball of the comma, and the fence spirals inward for a loop, trapping fish in a pool. they can't figure out how to reverse course or swim against the current, so they become concentrated in the ball of the comma, making them easy to net (vine nettings), brain (with rocks), or just get in and throw them out by hand. Plus it keeps them alive and fresh until needed. Other fish traps are ancient also; see this weir (could be build with rock), and the double-heart (which is built with rock), both of which can be adapted to work offshore in a current, both of which can be built quickly by many hungry settlers working together. [Fishing Wier.](https://en.wikipedia.org/wiki/Fishing_weir) Click on the picture to enlarge. [Double Heart of Stacked Stones fish trap.](https://en.wikipedia.org/wiki/Double-Heart_of_Stacked_Stones) Click on the picture to enlarge. so we have food and water (steam distilled ocean water, can be made even using clay pots), and quick shelter. The society progresses by steam engine and quickly implementing their knowledge of basic sciences. They will arrive at a full electrical stage within a century, IMO. Of course they don't use traps forever, they will be building steam powered boats and fishing nets pretty quickly. Other details (crops, what they can use for fiber and rope, whether they have coal or oil products) are all going to be peculiar to what you put on the planet for them to use. Something like cotton would be great for a textile industry, but what they get is up to the planet designer, or perhaps additional world-building questions. You want those knowing the most about geology and mining in the group to focus on finding simple ores for tools, and progressing toward iron. Flint is not of biological or animal origin; that is the first thing to find; it can be shaped by using flint rocks as hammers, knapping can be self-taught to make razor sharp hand tools very quickly. These can be used for simple tasks like harvesting plants for fuel and food, killing and butchering fish, and digging for ores. The majority of people can be put to work both on these tasks, on building fish traps, and on becoming specialists in making these tools. Use other specialists among the 40,000 to make teams of surveyor/explorers; to find the best candidate places to settle: For fish production, farming potential, and mining potential. If possible for caves that can serve as initial shelter and shade from the weather. Use plant specialists to understand and start categorizing the new flora (categorization being the first step in science), with an eye on finding fibrous stalks, leaves, or roots to be able to make strong ropes and nets (for fish and woven mats that have utility in shelter and comfort). ]
[Question] [ I have this medieval world with this big realm. Its climate is dry and warm and the main issue is what to drink, how to do the hygiene, agriculture etc. They have no access to seas nor mountains. There are some rivers, but they're often dry and not so wide (therefore using pumps to fetch the water from these sources is not a lifesaving solution), but all the water they have is from the rivers - it is not enough though and people die a lot because of dehydration. Simply water is rare in general. Digging wells is not a good solution either because the water is really deep in most of the country. Rains also come very rarely, two or three times a year maybe (but when they do they are steady and heavy, they can last a week or even more). My ideas: * They could import water from distant places in tanks, but that is not so effective (especially when they need so much), probably very expensive and there is higher risk that the water will be tainted. * They could somehow store the water from the rains, but I don't know how (also risk with contamination). They have a really good king with a smart government and they want to help people and the realm. Also, the realm is quite rich, so they are able to invest a lot of money and energy in solving this. What possibilities do they have? [Answer] It's highly unlikely that a rich, centralized realm would come to existence under the given circumstances. But the only reasonable solution (if there is no magic) would be to store the rainwater in some form of cisterns or stepwells. <https://en.wikipedia.org/wiki/Cisterns_of_La_Malga> <https://en.wikipedia.org/wiki/Stepwell> They should be guarded, and those who dare to steal or contaminate the water, draconically punished, but as you can see, such facilities was feasible even in the ancient times. They would be built and maintained by public works, which would also encourage lazy waterwasters to migrate out from the overcrowded country. EDIT: As far as understand, the shortage of water is not a consequence of some sudden catastrophe, but a natural property of the region. This would prevent people from doing effective agriculture, and leaving the area loosely populated with nomad pastoral folks. (just like deserts and half-deserts in the real world.) This wouldn't allow centralized government. Since humans (and most animals) tend to not multiply if the basic conditions of life (food, water...) are missing, such a setting is unlikely. (Expect climate change.) EDIT2: You have stated in your comments, that by the time of the founding of the Kingdom there were enough water, but now there is less in every year. If this trend will continue, even cisterns and aqueducts would become useless. So my ultimate advice to the King: Prepare a force as fast as possible, go, and conquer some water-rich region, to provide new home for your people. If the country is going to be deserted, this is the only way. [Answer] You have basically just described what happened to the Indus Valley Civilization which was very reliant on a single river system which started to dry up.If your rivers are actually running dry you are even worse off. The result was the slow collapse of their civilization as they lose the ability to feed themselves and thus can't support specialists. This causes a slow decline in and eventual loss of the so called hallmarks of civilization like writing and metal working. Trade civilizations are even worse off, since trade relies on access to water, No one is going to trade with you if you have nothing to trade and can't even provide a reliable abundant source of water for caravans. Eventually it leads to the abandonment of their cities. They really can't save themselves by building things becasue they really can't support the workforce needed to build things like dams and reservoirs with a failing infrastructure. Not that they would help when rain is as rare as you say, your reservoirs would need to be on a scale dwarfing even modern ones. Your king is helpless when faced with the loss of the primary vital resource from which all other resources stem. If your king is really benevolent and knowledgeable he will tell his citizens to abandon the country and move to another one. Your kingdom should already have widespread abandonment of settlements, political strife, and collapse of law and order. People in modern first world countries take water for granted but the effects of prolonged shortages are catastrophic. [Answer] **Upgrade the rivers.** If the rivers loose too much water before making it to the kingdom then you need to upgrade the rivers. As Mrkvička said, use aqueducts, but build them into the river beds. This will allow the kingdom to direct all the water from the river's source much further along the existing riverbed to the kingdom. Of course this will have been done long before the kingdom grew to its current size, since there is a catch 22 with having a large kingdom that hasn't ever had much water. [Answer] I think b.Lorenz has some good points. Another way for them to get water would be [aqueducts](https://en.wikipedia.org/wiki/Aqueduct_(bridge)), which is how water has been transported as early as 2000 BCE. To cite the Wikipedia article: > > Although particularly associated with the Romans, aqueducts were likely first used by the Minoans around 2000 BCE. The Minoans had developed what was then an extremely advanced irrigation system, including several aqueducts. > > > In the seventh century BCE, the Assyrians built an 80 km long limestone aqueduct, which included a 10 m high section to cross a 300 m wide valley, to carry water to their capital city, Nineveh. > > > One drawback with aqueducts, though, is that the water needs to fall. This means that you need to find a source of water which is higher up than the city you wish to transport it to. If there are no mountains or hills or any other high locations where the river (or lake, or whichever other water source they might use) originates, then it won't reach the city. On the other hand, it might be a way to get it close enough to make the final transport not that tedious. [Answer] Unfortunately you've got bigger problems than just having water to drink. The vast majority of water usage goes towards crops, which at this point should start to fail due to the combination of brief rainstorms followed by long periods of drought. I'm not sure an aqueduct would be enough to supply the entire kingdom's agriculture, and if there's no elevated water source very nearby then building the thing could become very complex (the longest the Romans ever built was ~130 km). To solve this, we need to know more about their situation. To be a wealthy medieval kingdom despite the lack of agriculture implies they are either involved in exporting valuable commodities (gold, spices, etc), or are at the crossroads of several major trade routes. Fortunately, both scenarios imply trade is already common and feasible. My Solution: Definitely try to build an aqueduct to supply the cities if you can, and deep wells to store rainwater wouldn't go amiss either. Also make efforts to urbanize most of the population so they have access to this new water infrastructure, while the former agricultural land is given over to grazing. Then, begin importing vast amounts of food to make up for the shortages. Rafting it down the aqueduct could ease travel? Otherwise just use wagons. Unlike water, beer doesn't spoil, so if you ever need to transport water without the help of an aqueduct, consider using beer instead (the Royal Navy did this during the Age of Sail). And, pray this source of wealth doesn't dry up and that your grain supply doesn't get cut off. Also, invent stillsuits. [Answer] People dying of dehydration is pretty bad. But they were probably already sick. It used to be that people did not drink water. People drank wine or cider exclusively. It is good, has caloric value and the production techniques mean that there is little chance of having some dude's feces in your drink. I think it is Rats, Lice and History that describe a Spanish army on the march which ran out of wine; following this 20,000 soldiers died of dysentery. This means to me that before they ran out of wine, these soldiers drank only wine. If you have an occasional rain that lasts a week that will work. You allude to this with your comment on storing water in tanks. That has been done in the middle east for thousands of years. Underground stone cisterns caught and kept water from infrequent rains. There were channels to carry the water there and so on. Cool stuff. And you already have the government to make it happen. Here is a link to get you started. <http://www.haaretz.com/israel-news/israeli-archaeologists-uncover-3-000-year-old-cistern-in-jerusalem-1.463226> So 1. What to drink: wine. Make it from melons if too dry for grapes. 2. Agriculture: dryland crops. Lithic mulch! 3. Hygiene... explain some more this thing "hygiene". [Answer] Look at the city of Rome as an example there are the over ground aqueducts that we see some still surviving. But more importantly the Romans built many underground pipes and tunnels which are large enough to drive a car through, even today some are still used to bring water into Rome. The Romans developed the below system and many others. <http://www.spiegel.de/international/world/rome-s-tremendous-tunnel-the-ancient-world-s-longest-underground-aqueduct-a-612718.html> There is also Archemedies water screw which was used around 740 BC to bring water from low areas to high areas, with enough of these and good water ducts you could get water anywhere, combined with what the romans used it can work. <https://en.wikipedia.org/wiki/Archimedes'_screw> Don't forget that there are many other cultures that probably built similar systems that have been lost to time. Its just down to your imagination. Also the romans used volcanic material mined from under Rome and other areas to create a type of concrete that was water proof and was perfect for transporting water with a low loss compared to today's technology. If the realm is rich and smart then they could develop technology like the Romans or they could attack and steal it from someone else. ]
[Question] [ In my fictional world there are small organisms the size of a dog or smaller,some have the shape of mini-volcanoes, while some are stuck between rocks, they don't move and live in both sea and land. This organism doesn't have natural predators as not being edible, it's as hard as rock and isn't killed by the digestive system of any animal. However it releases a waste product, it's a red liquid similar to blood and some animals feed on it, if they find one while it releases it's waste product,some other colonial organisms farm them just like ants farm mushrooms on earth. If animals feed on it, then it might be nutritious and contain minerals or other things... so what reasons does this blood fountain have to give up this nutritious liquid? [Answer] Warning: This answer is slightly mature, but is done in a strictly biologically speaking context. The male creatures could release some version of fertilization, and use the animals that drink the liquid to spread the fertilization on the slopes of the females (as excrement), and the females absorb the fertilization for offspring. Similarly, the females could produce very, very small fertilized eggs that the animals would likewise spread through excrement. Both aspects are very similar to how many plants spread via berries and animals spreading the berries' seeds, and also draws some parallels with bees spreading pollen. [Answer] Continuing with the "ant" example you mention: I believe you're reffering to the [Leaf-cutter ant](https://en.wikipedia.org/wiki/Leafcutter_ant); These ants basically "farm" a type of fungus for food. This is a type of mutualism, as both species depend on the other to perform some function (protection, nutrition, etc.). We see a similar function with Ants and [Aphids](https://en.wikipedia.org/wiki/Aphid). Aphids produce a sweet nectar like substance that the ants eat, in turn the ants provide protection. In some cases the ants actually shelter Aphid eggs in their colonies over the winter; come spring the ants bring eggs out to plants that the aphids will feed on. In a similar way your blood fountains could simply be in a mutualistic relationship with another organism. Perhaps being immobile they need swift creatures to bring them prey that they digest, then they excrete the parts that they don't need for nutrition that their swift companions DO need for survival. Perhaps what the Blood fountains digest is normally "junk" by other creatures standards? Something like a clam's actual Shell? The waste product may just be something useful to other creatures like carbohydrates or fat; but not necessary for your Blood Fountain's biology. [Answer] My first thought was salt, for something a creature might want to get rid of, that others still might want - and you wanted it red, so maybe iron, or other hard minerals. Partly inspired by the threads on a creature's fear of water caused by osmosis, to be fair. It looks like the creature is living in fairly mineral rich environments - in between rocks, near the sea, and they don't move so must have some way of regulating themselves of minerals present in high concentration. Most creatures can tolerate a fairly narrow band of salinity, because osmosis will lead to too much or too little water pressure. Other minerals are also helpful in reasonable amounts, but dangerous if the amounts get too high. If the creatures are living in areas where the mineral/salt content may vary, since they can't move they have to have some way of dealing with the excess - in this case, instead of regularly getting rid of them, it is expelled once it builds up to a certain point. Since the hard minerals are still good, other animals may benefit from them - which has an additional bonus of tending to carry them away from an area where the concentration is too high for your critter. If the products are mixed with the creature's usual waste, that might be a problem for other animals using it, since it would also have the toxins and byproducts the critter needs to rid itself of and which other animals won't want. It may have evolved to expel different types of wastes separately, perhaps the red is specifically beneficial because it contains mainly concentrations of minerals and salts, and there is some other waste product(s) that contains the toxins, that animals can avoid. Of course, this adaption only makes sense if the creature benefited from the animals' presence somehow, maybe the increased traffic means more manure to grow the plants it eats, or attracts whatever its prey is. [Answer] Other than the reasons mentioned by others, the liquid could attract animals that the organism then kills. The most likely case is that the blood itself causes the death of the animal or atleast causes it to fall unconscious. Though if it did this regularly it would be easily avoided by the smarter animals. ]
[Question] [ I'm the chief security officer of a major (fictional) cell phone manufacturer, and after [two months of not being able to unlock the San Bernardino shooters' cell phones](http://www.latimes.com/nation/la-na-san-bernardino-phone-locked-20160209-story.html), the spooks are getting fed up and demanding that for my next generation of cell phone models, I include some mechanism by which they can access the encrypted information held inside a terrorist's recovered cell phone. They say that if I don't make this work, they'll have me fired and replaced with someone who will... but the classic solution (install a software back door that is activated by a secret password/technique that only the government knows about) is a non-starter for me, because it's become obvious that the government [isn't much better at keeping secrets](https://en.wikipedia.org/wiki/Edward_Snowden) than anyone else, and it would just be a matter of time before all the world's baddies knew the secret password/technique also, at which point my customers would be very unhappy with me. What I'd like to implement instead is a mechanism that will still be secure even if everyone in the world knows all its details, because only a very well-funded major government would have access to the physical resources necessary to perform the unlocking operation. As a (not very well thought out) example, the phone might unlock itself if it detects that it has been floating in zero gravity for more than an hour, on the theory that only a major government could afford to place the phone into orbit. Is there any practical way to implement this (that doesn't involve launching critical evidence into orbit)? [Answer] ## Let it depend on a many keys, not one I believe you could construct such an unlocking mechanism, tailored for a specific government. It must not rely on a single key, but on the combination of several one-time keys issued to the members of some legislative or executive body. (Parliament/supreme court /etc) The phone will only unlock given the keys representing a majority of that body. Naturally the identity of the representatives thus voting for an unlock will be logged, making them accountable. This way the "government" you trust is not some secret three letter organisation but the actual, accountable, formal government. Of course this is not completely safe. Human error plays in etc (but that can be part of your plot) However to abuse this back door you will need either a coordinated effort by several chosen representatives or to somehow gain illicit access to a large number of personal master keys (as opposed to one). Point being: a system that uses the checks and balances used in a (democratic) government. [Answer] ## There is no way... almost I'd say the original goal - design a smartphone with a universal built-in decryption mechanism - is impossible to achieve. Encryption strength depends on the algorithm and the data, not the media. So it's about software, not hardware. You can't make a phone, or a flash drive, or a DVD drive that allows you to do that, since it doesn't depend on media. However, there are several options: ## Option 1 - continuous logging Assuming the phone itself was being used for decryption at least once, when you have the phone and the encrypted data inside but don't have the key, the only thing that could help you is a logging system. If a phone logs all the actions it's doing, it could help to recover the data. However, that means a lot of debugging information (dumps, logs) being transmitted or recorded all the time - not very plausible scenario that terrorists won't notice anything. ## Option 2 - using only government approved software There are algorithms allowing you to decrypt data using some kind of "master" (or, say, "recovery") key. These algorithms are used in enterprise solutions. The "recovery" key must to be used beforehand, in order to generate a keypair. All you need to do is to force end-point customers to use the one and only encryption software. So yes - technically it IS possible, still not very feasible though. ## But all this won't work Let's assume there is a smartphone design, that actually allow the government to decrypt all the data inside the phone. Let's believe, that the government forced all of its citizens to change their phones to the new one. Let's dream, that all other phones (including foreign ones) were destroyed or don't work anymore. **Will terrorist use that phone to store sensitive information?** The phone from your example was used just because it was secure. If not, a plotter could use any other device (say, a laptop) for encrypting and storing their info, keeping the phone for communications only. [Answer] # No way, and not for a technical reasons But for human ones. Government is but a set of humans. Nothing more, not really. So some humans have a backdoor. After some time the same humans are not a government. But they have knowledge. If there is a device to dispense one-time codes, they can get hundred of keys with them. They can get a plans and RNG seed. They can ask their successors for access. While still in government, they can sell access. It might be tempting. Or they can hire you to debug a glitch in the system, and then you have access. And so on. **No thing about *government* would prevent leak of access.** And if you can design and manufacture once, you can repeat it. [Answer] The NSA has to have much more computing power then anyone else (probably true today), cyphers with short key length can be secure against anyone else but not the NSA (this is thought to be why the DES key length was lowered from 64 bits to 56 bits, 256 times less secure). Since hardware computing power doubles every 18 months, the NSA would have to be far ahead to keep up. One way they could *really* be far ahead is with quantum computing. An alternative approach is to make a back-door that depends on chips that do not release the keys inside, they are embedded in hardware with a self-destruct mechanism to prevent access to decryption keys. [Answer] Short answer You cannot. Long answer Since what you are looking for is a key escrow mechanism, the problem is that there is no way to build a backdoor that enable the good guys to access and the bad guys to stay locked out. Every technical solution you implement had the weakest point in the humans. Even a scenario like the one suggested from @ConfusedMerlin in the comments has the problem that the key can be stolen/sold. After all, how can be sure that the key is used from the right guy ? Anyway, [XKCD has already the solution](https://xkcd.com/538/) [Answer] **Use slightly weak encryption** Liaise with that three-letter agency. Find a crypto algorithm which the government's resources can break by brute force in about a day. This means that most bad guys simply won't have access to the means, and rarely any profit motive to try. The exceptions would be the largest corporations who manufacture computer hardware, but in almost all cases the threat of criminal prosecution and huge fines will deter them. If IT hardware continues to advance roll our a software upgrade that slightly hardens the encryption so as to restore the agreed difficulty. There will be a problem in that the government will press for weaker crypto that is cheaper to break. You'll need to convince them of the economic harm to the nation that will follow from criminals gaining an economic incentive to break the crypto. Ultimately since the government makes the laws it holds the whip hand. If you lose this argument your business us doomed, but if the government just banned all but trivial crypto it's doomed faster. If a deal is done then it's nature could be informally leaked. Yes, the government can crack your phone if it *really really* wants to. It will cost tens of millions for your spouse, your enemies, your business rivals, criminals, journalists etc. to even try, so mostly they won't. [Answer] # Make your key out of something weird We use lots of different parts of the electromagnetic frequency for communication. I suggest you either build your new gizmo to communicate over a part of the EM spectrum that is difficult to produce/modulate/receive or perhaps by using a small enough modulation that only a well funded government could detect it. The answer could be radioactive materials. Certain elements in existence are not found naturally on earth, and have only been created through human processes (i.e. fission). So your phones could have a gamma ray detector that decrypt the data store in the presence of an encoded signal from one of these materials. Would-be hackers would need to steal your private key, some highly controlled substance only produced in nuclear reactors, and a way of modulating the signal. You could advance the idea further into sci-fi by creating a quantum key out of such rare particles. Some atoms can only be produced in lab conditions and live for fractions of a second. You could produce some of these particles and control their spin, encoding your private key into the particle states. The second idea was around high accuracy modulation. A topical example of this is gravitational waves. Detecting such waves requires incredible equipment (4km long lasers). An anaology would be the first person to ever invent a lens - he could write so small that only he, with a magnifiying lens could read what he had written. The first example was having a key that is really really hard to produce, even if you know what the code is. In this case I assume the phone has a detector than can easily read the key. In this second example (of high accuracy modulation), the key is really really hard to read and I doubt the phone could be given such capabilities. So I think the phone would need to transmit a public key (which would change regularly), your spook-types communicate back with the public key and then they exchange a symmetric key to encrypt further communications. Basically, it makes more sense to have a key that's really hard to make. If its really hard to read the key, rather than make it, it makes the transaction a bit more difficult. [Answer] # Key Strengthening or Weakening A recovery key is created but not given to anyone (the phone keeps the public key, and tosses the private key). The NSA can crack it in a reasonable length of time, but only that unique dedicated hardware can do so. A public/private key algorithm and size is chosen so that cracking it is in reach only for the NSA’s special computer. On a programmed schedule it adds bits to the effective key size, to keep pace with Moore's Law. --- Details: a public key is in memory so we need asymmetric encryption. It creates a random session key for data, and encrpts *that* with the normal user’s key, the designated recovery key for company-owned phones, etc. and the NSA weak key is added to the list. Those encrypted keys are stored with the data block. Of course, it could just use the weakened key for the normal uses and ot need a separate government key. But, this additional key could be hidden away so it might not be noticed by others examining the encrypted data format. But if (when) it *is* discovered, only the NSA can crack it in a reasonable length of time, and only on their dedicated system for that. [Answer] # Zero G won't work The 0g mechanism you designed would not be secure. All an attacker would have to do is open up the phone and replace the accelerometer that can detect acceleration, with a device that behaves electronically like an accelerometer in 0g. [Answer] Another answer **Short of detecting that it is in orbit** have the phone unlock itself if its GPS detects that it is at (a) particular location(s) agreed with the government. That location is militarily secure. Maybe inside the location where they assemble nuclear warheads? Should be about as secure as possible. Or at 3000 ft. above such a location and moving at 10mph, which requires being in a helicopter in some very well defended airspace. Only question is how easily can GPS satellite transmissions be spoofed? [Answer] A simple answer: Use a [Software Protection Dongle](https://en.wikipedia.org/wiki/Software_protection_dongle). It's basically just a electronic storage device that has some cryptographic key in it. When the phone sees this key, it'll open up (or do whatever the government wants it to do). If you use secure cryptographic techniques (that update with the state-of-the-art) you can ensure the phone is secure. Everyone can know there is a key, and even what cryptographic algorithm was used, but they can't figure out what the key is without government-level computing power. (Or even with government-level computing power, if you want) [Answer] **It seems plausible** I actually wanted to answer that such a thing is simply possible, but to be sure one either has to find or design a protocol and I do not have time or skill to do either. I will however sketch what this could look like. First of all elliptic curve cryptography is a kind of cryptography that is currently widely used in practice. As such it is a tested method. The idea is that people can exchange passwords with one another without an eavesdropper finding out what the exchanged password is. Now there are many different elliptic curves and for an elliptic curve protocol only one elliptic curve has to be chosen. This choice is important because some of the curves are essentially flawed and using them would be insecure. It is however plausible that an elliptic curve can be constructed that is flawed in such a way that only the constructor can exploit the flaw. (e.g. The constructor might now the number of points on the curve or even the prime factorization of this number.) Exploiting this the constructor could be able to decrypt anything that was encrypted using this curve. In your situation the government (or a department thereof) should construct such a protocol and issue that to the phone companies. As long as they keep the exact details of the exploit to themselves they will be able to eavesdrop on anyone. Note1: This does mean that the government can be completely open about what they are doing. Since to actually use the backdoor you need the secret key that only the government has. Note2: Great care should be given to keeping this secret key, really secret. This is however not impossible. Note3: This is of course not perfect. Terrorist might simply decide communicate using a secret code of their own. But this is more or less the same as not using phones anymore. Edit: I just re-read your post and noted that you did not want to let this rely on the government keeping things secret. This is still possible in a way. What can be done is embedding the final key in one unique object in a way that it can be used, but not recovered. So there is one physical device that can decrypt everything. ]
[Question] [ Is there any combination of factors that would allow the average human to walk on a cloud without the aid of magic or technology? If so, could buildings and cities be constructed on clouds in those conditions? By "the aid of magic or technology," I mean only that the aid in question is actively or passively causing the appearance of the user walking on the cloud. Aid in the form of protection against the environment is acceptable, but a jet pack is not. [Answer] ... Not really, I'm afraid. Clouds are just water vapour, they would put up very little resistance at all if you were to step onto one. So, outside of magic or technology, no, no way on Earth. Which is really begging the question: are we talking about Earth? The physics of other planets could be different. But if you want humans to walk about unprotected, I'm afraid it'd have to be so close to Earth that the answer is the same: without magic, or technology, clouds are quite literally as insubstantial as mist. --- I've thought about it some more, and I think the answer is still no, for any reasonable definition of "cloud". The reason is, for a cloud to be substantial enough to walk on (let alone build on) there would have to be some force holding the cloud together, and that force would have to be stronger than the force of you (or your building) forcing it apart. For vapour (of whatever substance) there just isn't enough force keeping the particles together: effectively, you're just standing on air. Now, that *does* raise another possibility: what if you were less dense than the air? Well, then you'd float on top of it! (Or rather, you'd float at a particular altitude where your buoyancy cancelled out the force of gravity, but that's about the same.) Ignoring the clouds entirely for a moment, that would almost get you what you're asking for, but it would be like floating on a lake, not like standing on solid ground. However, there *are* floating buildings in our world, so you could just build a platform that floated in the air, and stand on that! Now, that does sound a lot like technology, but what if there was some natural material floating in the atmosphere too? That could form a natural platform that perhaps you could walk on, and that might meet your needs. It wouldn't be a cloud: if it were just vapour, you would sink into it and float, as if it wasn't there; but it might be good enough, and your characters could stand on it and even build on it if it was substantial enough. [Answer] Based on this question/answer: <https://physics.stackexchange.com/questions/25918/> There is a place you could kind of do this, namely one of the gas giants. If you fell into a gas giant you would fall until you hit a point where the cloud density matched your own density. If you were wearing an unubtainium suit that kept you from being crushed, you wouldn't really be able to walk, but you would bob about nicely like a cork on the water. If you think about it, water is much much denser than cloud, and it's pretty hard to walk on. You can do it with [water walking shoes](http://graphics7.nytimes.com/images/2004/08/02/business/02pate.xl.jpg) which are essentially feet boats. So could you make shoes that let you walk on clouds, without using the principle of lift? On Jupiter, maybe... down where the clouds get as dense as water. **EDIT:** More thoughts... So, why can't we walk on water? The problem is that the water molecules are loose; they move about freely, this way and that, and when something pushes against them, like the bottom of your foot, they just move out of the way. But sometimes an outside event can cause the molecules to become fixed in place, frozen if you will, and when that happens they don't move when pressure is placed against them. Clouds are even less cohesive than water because the density is a lot lower, and because the density of ice is greater than air, [there aren't really any natural ways to freeze a cloud on an Earth like planet, but there may be ways to do it if the atmosphere was very alien](https://scifi.stackexchange.com/questions/73475/how-can-the-frozen-clouds-on-dr-manns-planet-stay-afloat). Straying into the magic technology arena, there might be a way to generate a field that holds the cloud molecules in place (magic), or the clouds are made of aerogel (technology), but without that you're going to have to have a very dense atmosphere, where some of it can freeze out and float up above the surface like a cloud. If something like this is possible, the best candidate in our solar system is [Uranus](http://www.space.com/18708-uranus-atmosphere.html). > > As on Earth, the atmosphere of Uranus is broken into layers, depending upon temperature and pressure. Like the other gas giants, the planet doesn't have a firm surface. Scientists define the surface as the region where the atmospheric pressure exceeds one bar, the pressure found on Earth at sea level. > > > Just above the "surface" of Uranus lies the troposphere, where the atmosphere is the densest. The temperature ranges from minus 243 degrees Fahrenheit (minus 153 degrees Celsius) to minus 370 F (minus 218 C) , with the upper regions being the coldest. This makes the atmosphere of Uranus the coldest in the solar system. Within the troposphere are layers of clouds — water clouds at the lowest pressures, with ammonium hydrosulfide clouds above them. Ammonia and hydrogen sulfide clouds come next. Finally, thin methane clouds lay on the top. The troposphere extends 30 miles (50 kilometers) from the surface of the planet. > > > So if you were going to have clouds that were solid enough to walk on, that would be the best place to start. [Answer] There's nothing that would let a human walk on clouds even with the aid of technology. Clouds aren't the small, compact things they look like from the ground, they're massive things sometimes spread out across miles. If you look at one up close, it doesn't look like a solid structure with clearly defined edges, it looks like a roughly defined mist. Which gives us the key problem even if we ignore the fact that they're not strong enough to hold you up. If you actually get up there, there's no ground-analogue to walk on. [Answer] Part one of your question is impossible, but part two (can you build cities and buildings in the clouds) oddly enough isn't with a slight adjustment to your thinking. Buckminster Fuller, who invented the Geodesic dome, observed that as you double the radius of the dome, the interior volume increases 8X. After a certain point, the mass of the entrained air becomes greater than that of the material of the dome itself, so if the air were to be heated, it would then displace the cooler air outside and the dome could, in theory, lift off with as little as a 1 degree F temperature differential. The reason sports stadiums don't take flight today is this effect only becomes pronounced when domes reach truly gigantic sizes. A dome would have to be on the order of a kilometre in diameter before it could take off with a reasonably small temperature change, and a dome that carried hundreds or thousands of people (like a flying cruise ship) would need to be much larger to have sufficient lift capability. Going back to individuals, a person could float solo with a balloon of sufficient size or lots of small balloons (people have lifted off in lawn chairs with hundreds of helium party balloons tied off to them), so there is a [ossibility of getting close to the effect you are envisioning. [Answer] Here's a arachnophobia inducing idea: > > Spiders. Spiders everywhere. > > Imagine a colony of spiders that weave a web so tight that it traps air. Then one of two things could happen: (1) through some biological process the spiders/their webbing removes gases other than hydrogen, leaving the air pocket less dense than the air around it or (2) the webbing traps heat well, keeping the air inside warmer (and therefore less dense) than the air outside it. In either case, that would cause the spider colony to airlift themselves to a new location. These aren't exactly clouds, but a flying web like this would look like a cloud and could be strong enough to walk on. Also, it wouldn't be too hard to imagine a world in which spiders have evolved this mechanism to move en masse to a new location as a form of seasonal migration. > > > You wouldn't be able to (and I doubt you'd want to) build anything on a cloud like this, though. [Answer] Each cloud is essentially a bunch of water droplets and snowflakes. You could probably compress and freeze a part of it to have a more solid snowy/icy surface, but your result could obviously start to fall down. ]
[Question] [ For my Alternate history story, I want a new ethnic group with their own landmass. Said landmass is a perfectly circular island the size of Egypt (area of 1 million square kilometers). This island landmass will have a tall mountain range in the center and the rest will be grassy plains. Given this criteria, what location on Earth will provide a climate for the island very conducive to arable land? Clearly the poles are the wrong answer. That said, I'm not sure the equator is a good answer either. The island will be a million years old if it matters. [Answer] ## -37,-125 Dead center of the South Pacific, within the temperate zone. You'd get more arable land if you put your mountain range on the NW edge, but this is where you'd want your island country to be. Additionally, the rest of the world might not even notice it until the 1600's. [Answer] **Between 30th and 45th parallel.** Theses lattitudes gives you what we sometimes call a Mediterranean climate and around-a-year growing season. Closer to the equator will give you first dry zone and then wet tropical zone. Former running the risk of insufficient rainfall, the latter having the growing season interrupted by heavy rainfall. Go pole-vise and you start seeing the growing season interrupted by regular cold winters. Put your island few miles north-west from [Madeira](https://en.wikipedia.org/wiki/Madeira) (32°39′4″N 16°54′35″W) and the Gulf current will keep your climate cozy and stable. [Answer] Certain countries have far more arable land than others. There are multiple reasons for this, but geographical location makes a huge difference. There are good reasons that Greenland is generally inhospitable while China has 1.4 billion people. This map here displays the percentage of arable land by country: [![Farming Land Ratio](https://i.stack.imgur.com/41AMo.png)](https://i.stack.imgur.com/41AMo.png) The places with the best farmland seem to be Europe, Caribbean, South Asia, and West Africa. I know India and Bangladesh are very fertile thanks to mountain rivers, but overall placing your island next to a country with lots of arable land will generally lead to your new landmass also having the right climate and other attributes to have lots of cultivated land. An Egypt-sized island can't really fit in Europe, but a large island just south of India (Delhi is 28.7041° N, 77.1025° E ) or west of Nigeria ( Lagos is 6.5244° N, 3.3792° E ) would be good locations for your island. [Answer] Anything around the same lattitude as England/Europe or New Zealand. You get the best of both worlds - enough rain that you rarely worry about drought, enough summer that the crops grow pretty regularly. Add on top of that either some Volcanic soil with flat-ish fields or at least rolling hills - and you are onto a winner. ]
[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 last month. [Improve this question](/posts/251420/edit) The worldbuilding context is that I have a character who is in a terrible urban-fantasy situation, and is led somewhere where there is something he could use to defend himself with. It's unfortunately a chainsaw. The person who led him there is the ghost of a teenager who had no idea chainsaws are terrible weapons. The person he led there is very aware of this, but decides to use it anyway, because something is better than nothing. The character will need to use it to defend himself against humanoid monsters - many with clothing - and dog-like beasts. I'm focusing on cloth, because I'm supposed to focus on one question here, but if you all have thoughts about flesh and fur, totally feel free to throw them out. The chainsaw in question is a standard gas chainsaw one might see in a logging operation. My question is, where would you say is the line between plausible and nonsense, in terms of how much cloth (the biggest enemy of chainsaws I've gathered) one can cut through before messing up the chainsaw? Or is it just more of a roll of the dice/clothing thickness thing? [Answer] **Frame Challenge** There are *plenty* of horrendous accidents involving chainsaws where ordinary clothing had virtually nothing in the way of protective properties. Now, there are chainsaw chaps which have multiple layers (Stihl advertise 6 separate layers for theirs) of cut-resistant material - and these will absolutely stop a chainsaw (plenty of videos online of them doing that) but these are not regular clothes or clothing material. Realistically - the most anyone would be wearing is 2-3 layers of normal clothing - and if they are humanoid monsters, the chance it would be fully intact clothing is minimal. So in short - I don't think you'd have much trouble. The reasons a chainsaw isn't a great weapon is more a combination of weight, noise and ease of control. Once you've made contact and can keep the RPMs up - it will quite happily make a mess of flesh and cloth. [Answer] The first piece of clothing he tried to cut would probably entangle his chainsaw and jam it. You'll still make a mess of a guy in a t-shirt, but you'll need to unjam it for the next. If you just chop and pull off then you might be ok for a while as it's still attached to whoever is wearing it. But sooner or later it will jam, probably sooner. Chainsaws only rip through things really well if the thing is rigid and anchored. [Answer] Cutting with a chain saw is about moving X number of blades past a target faster than the target can naturally bend. The blade action cuts through the target. The blades on a chain saw are bent in a way to help move wood out of the way clearing a path for the bar to move through the block of wood. If I were preparing a chain saw to go against cloth wearing animals, I would change the angle of the cutting blades to simply be straight cutting. There is no need to move stuff out of the way of the bar. Now, I have so many small knives moving through cloth and flesh which would be far more "self clearing" meaning far less likely to grab the clothing and clog up. Finally, there are "carbide tipped chains" for chain saws which are used by fire departments to cut through reinforced walls. The usefulness depends on how many monsters one would have to face in a short amount of time. If the protagonist has time to stop and rip out the clog, they can use it for long enough to empty the gas tank. Edit: When I look at my chainsaw chain, it has a blade, then two humps before another blade. I believe those two humps are to help move chips out of the way. But those humps might be what catches clothing and pulls it into the gearing. Changing the chain so that it only has blades may make a big difference in catching on the clothing. [Answer] For this answer I will assume a standard chainsaw, i.e. not one used in the logging industry, although the answer could still be valid in case of the latter. --- * I can imagine the maximum lies roughly **around the height of the chain**. Chains on standard chainsaws are naturally slightly loose. The problem with cloth and other 'fibred structures' is that these will easily get drawn along by the hooks if the saw only catches them, but doesn't cut them (I'm not sure what the ratio of *fibres caught* vs *fibres severed* is, but I believe it is substantial enough to merit this answer). Especially when a chainsaw is used to attack moving targets, cutting them at various angles with varying amounts of force, a mass of cloth of sufficient rigidity might reach beyond the chain itself, and force the chain off of the bar, resulting in what we in the timber business call "a problem". * The **amount of layers** also might make a difference. With many layers there is the additional problem that they likely have different kinds of stiffness, of fibre length, strength, and elasticity, posing a structurally difficult mass to tear apart. * And then there is [chainsaw safety clothing](https://en.wikipedia.org/wiki/Chainsaw_safety_clothing#Trousers) which is made to jam chainsaws, so the **type of material** also matters for an accurate answer. ]
[Question] [ Let's say I want to write about a living thing that can naturally go to 99% the speed of light in just one second of acceleration. I would like to write what this being would experience at such speed realistically (Of course, ignoring the possible collateral damage and where it gets so much energy from, that would be a separate problem, maybe is a robot) but nevertheless, every time I see documentaries about things going "almost to speed of light" I see examples of two effects that are both supposed to be realistic but I don't understand how they are both possible at the same time -That at such a speed time seems to stop -That when the faster your relativistic speed gets, the greater your relativistic mass gets, and therefore when you get to another point, much more time will have passed than you felt I don't understand, how are both effects supposed to work at the same time? Why would have passed more time than the one you felt when you arrive at your destination if time is supposed to have almost stopped in your point of view? Or is "seeing things stopped in time" just a fanciful example of what would happen if someone could *react* at near light speed? The effects of moving at 99% the speed of light become more prominent the further you travel? (for example, the living being using his speed to travel a 100 km road vs. him traveling to the nearest star) [Answer] So far all answers have got the effects of relativity wrong resulting in incorrect and backwards results. The principle of relativity states that there is no privileged reference frame, and that the laws of physics take the same form in all inertial reference frames (i.e. the reference frames of free-falling objects). It follows from this that for a free-falling spaceship (i.e. one not being significantly slowed by interstellar drag, and not accelerating with its engines etc) passing by a planet at a significant fraction of the speed of light the spaceship will see the planet's clocks speed up or slow down by the exact same factor that the people on the planet will see the spaceship's clocks speed up or slow down. One of the other postulates of relativity is that light always travels at the same speed in all reference frames. From these two facts together we get length contraction and time dilation. Length contraction means that the people on the planet see the ship compressed along its length (and by the principle of relativity, people on the ship see the planet compressed along the direction of travel). Time dilation means that the people on the planet see the ship's clocks tick slower than their own (and by the principle of relativity, people on the ship see the planet's clocks ticking slower than their own). The relevant factor here is the Lorentz factor: *γ=1/sqrt(1-v^2/c^2)* This factor is always greater than or equal to 1. An observer on the spaceship will count this many ticks of their own clock for every tick of the planet's clock, whilst by the principle of relativity an observer on the planet will count this many ticks of their own clock for every tick of the spaceship's clock. Conversely, the observer on the spaceship will see this many of the planet's metre rulers fitting within the same distance as one of their own (on the spaceship), and of course, vice versa for the observer on the planet. This appears paradoxical because we are used to living in a Newtonian world where time and distance are absolute quantities, but this is not the case in Relativity. Most of these paradoxes can be resolved by giving up such Newtonian ideas. Now for other effects. Relativistic mass isn't really a concept used much these days, as it leads to incorrect assumptions down the road. Instead, we include the Lorentz factor explicitly, with *E=mγc^2*, ***p**=mγ**v*** etc. Unfortunately pop-science books and TV shows love it. The main other noticeable effects would be the [Relativistic Doppler Effect](https://en.wikipedia.org/wiki/Relativistic_Doppler_effect) & [Relativistic Aberration](https://en.wikipedia.org/wiki/Relativistic_aberration). The Doppler effect is similar in relativity to that of Newtonian mechanics, so you'd see objects ahead of you look bluer (or depending on the speed, possibly shifted into the ultraviolet or gamma spectrum) than normal, and ones behind look redder (again depending on the speed, possibly being shifted outside the visible range into the infrared or radio spectrum), but unlike the classical effect, objects perceived as directly to your side will also appear redshifted. The diagram below shows how the colour of uniform distant yellow stars will appear in different directions for an observer moving to the right with the Relativistic Doppler Effect applied on the top, and only the classical one on the bottom. [![relativistic doppler](https://i.stack.imgur.com/ojH8w.jpg)](https://en.wikipedia.org/wiki/Relativistic_aberration) Additionally, Relativistic Aberration (which is closely related to the Relativistic Doppler Effect) will cause objects to appear to be closer to the point directly in line with the direction of travel (i.e. directly in front, or directly behind). By the principle of relativity, the observers on the planet will also see the spaceship to be relativistically Doppler shifted (including being redshifted as it moves perpendicular to the planet), and to appear closer to the point directly in line with the direction of travel (i.e. further away than it is as it approaches, and nearer than it is as it departs). Note: so far I have only considered Special Relativity. This is sufficient to cover the case described in the OP, as special-relativistic effects will be much stronger than any general-relativistic ones. Special relativity applies to any motion on a "flat" spacetime (one where the gravity is weak compared to the scale of the experiment). If you start going near black holes or doing long-term observations at low speeds in gravitational wells you'll start getting other effects coming in (e.g. gravitational time dilation where clocks lower down a gravity well tick more slowly than those higher up). [Answer] Q: *"Would a living being moving at 99% the speed of light see time stop, or would it see time move faster?"* **Your own experience of time will remain the same** Living beings like humans don't "see time", we have no sense for it. The little beeper for time that exists in our brain will just pulse at some arbitrary, but regular interval, like a clock does. That is sufficient clue to provide the impression of time going by. It is regular, but you get deviations in time experience, when you are sleeping, dreaming, working, ageing, etc. When you move at 99% of c, you won't experience anything different. In a space ship built on Earth, you'll probably eat and sleep in a 24h time interval, because the ship's design is adjusted to Earthlings. Now suppose, you'd orbit Earth at 0.99 c in some wonder ship: you are not getting crunched because the wonder ship keeps you alive.. **Observing** As a pilot.. you'll notice there's something "wrong" with time when Analogy 1: ..you try to communicate using a wonder phone, with people on Earth. For them, time will elapse in their pace and because of your relativistic speed, you get squeeking responses, very quickly. It seems they don't need any time to answer your questions. When you play chess with them, they will be very strong, because they have 7x the amount of time you have. Analogy 2: ..you look at people on Earth. A place with people would seem like an ants nest, folks seem to move 7x as fast. When you would land after 4 years, 28 years of time went by on the planet. You'll meet your friends again, they are old people **Observers** When people on Earth.. Analogy 1: ..contact you to communicate using a wonder phone, it will take a lot of waiting time on their part, before you answer. When you answer, the sound you seem to produce is low frequency. When they play chess with you, they have to wait for ages. Analogy 2: When people look up to you, suppose there's a wonder telescope for that purpose as well, you would seem to be frozen in time, moving 7x as slow as the average pilot. When you land after 4 years, you'll meet your friends again, and they wonder why you did not age ! you are the same young person that went to space 28 years ago. Backgrounds in-depth: <https://physics.stackexchange.com/questions/634924/i-am-confused-about-the-passage-of-time-for-an-outside-observer-versus-an-observ> <https://physics.stackexchange.com/questions/109776/how-long-would-it-take-me-to-travel-to-a-distant-star> <https://en.wikipedia.org/wiki/Twin_paradox> [Answer] **Aspects of your question have been discussed via a couple of questions I've previously asked, and they're worth looking at** * [What does the view outside my ship traveling at light speed look like?](https://worldbuilding.stackexchange.com/q/147641/40609) * [Does my shipboard computer slow down as I approach light speed?](https://worldbuilding.stackexchange.com/q/106525/40609) **Here's a summary** One of the things that makes relativity difficult to understand is the all-too-human desire to see everything "from my point of view." Why this makes relativity difficult is easy: it's all about seeing things "from another point of view." Let's assume for convenience that your creature needs a single hour to accelerate from a planetary orbit to the speed of light. That's a breathtaking amount of acceleration that's likely to kill the creature long before it gets to the speed of light (i.e., within the first few seconds of acceleration), but we'll ignore that. One hour to leave orbit and hit the speed of light. From the point of view of someone watching your creature, they see it disappear from sight very quickly. Then it's gone for however many years are required to get from the observer's sun to the next solar system. Let's assume that same observer could know when the creature appeared at its destination (don't ask how, it's basically magic from the perspective of science). The observer would see the creature (quite literally) suddenly appear and move into orbit around a planet in that system. Remember, total time experienced by the observer is the number of years represented by the distance between the two stars in light-years. *From the point of view of the creature* it spent about 30 minutes accelerating, about 30 minutes decelerating, and was happily around the new star. An hour of its time. *If the first observer were magically able to see the creature while it's fully accelerated* (which the observer can't, but work with me), the creature would appear frozen in time. The creature, of course, can't magically see the observer (who would appear to be moving really, really, really fast!) because *time has stopped for the creature from the point of view of the observer.* The creature, of course, is aware of none of this. Time seemed to flow normally for it, it just happened to pass through a blistering distance in the proverbial blink of an eye. This is the nature of relativity you're seeking to understand. The faster you go, the slower time appears to flow *compared to an observer still experiencing life at the location where you started from.* But your experience is very different. From your point of view, nothing changed! What happened from your point of view is that a bunch of distance just... passed by... you didn't even notice it. **The real problem is, what's happening during transit?** A challenge that you need to face (one that's discussed in the first question linked above) is what happens while your creature is traveling? Your creature experiences infinite velocity or zero time from the moment it hits light speed to the moment it exits light speed. *But things are happening while the creature passes through those vast reaches of space.* It's a complicated subject, but think of it this way: the creature will have some number of photons that strike it during transit. Over the distance covered, that could be a *whomping lot of photons.* Anything from a suntan to being burned to a tendril of smoke could happen. The creature is also impacting atoms, molecules, and dust. All that is completely irrelevant at our very slow speed of space flight, but at the speed of light and over those distances, those impacts add up. Anything from having the leading edge of the creature abraded (e.g., rubbed lightly with sandpaper) to that tendril of smoke we just spoke about. The creature may even have trouble with gravity. At those speeds the gentle ebb and flow of gravity suddenly becomes a series of speed bumps, or waves being smashed through... or walls. I might have been a bit dramatic there, but I'd be curious if there's research into what gravity would "look like" to an accelerated object. I know what it's like to hit speed bumps with my car. I also know (to my everlasting shame) what it's like to hit a curb. *But here's the rub...* your creature *won't consciously experience any of that.* It's all happening during the time that "time has stopped" for your creature. Your creature isn't aware of time passing while its accelerated because time doesn't flow as we know it when accelerated. In the blink of an eye, it suddenly has a nasty sunburn, a big gash down one side of it, and a blinding headache. *That's all it knows,* assuming it survived the trip at all (it's your world, so it certainly can survive!). [Answer] The answer seems to be, unintuitively, **"yes"**. Think about it like this, the sun is 8 light-minutes away from earth, but due to its lack of mass, the photon emits experiences no time at all on that trip. Let's say for the sake of the illustration that it actually experiences one second. So then the photon would see 8 minutes of stuff happening within the span of one second. But if you stand across the room and shine a flashlight at me, from the photon's point of view, no time passes either. But also to us, it *seems* like no time as has passed. So if we again grant the photon a second to observe its journey, then we will appear to be frozen. Thus it seems to me that temporal compression is dependant on the distance traveled. As long as you don't ever hit 1c, then the traveler will experience *some* time passing. And so the amount of outside time being observed while traveling seems to be directly proportional to the distance traveled under relativistic speeds. If your story introduced some element of being able to speed up cognition, then that perceived "one second trip" could be any length of "time" needed. [Answer] **The being would experience some things differently, but not a subjective experience of time**. There would definitely be some weird effects. The being would, for instance, see length contract in very odd ways (counter-intuitively, moving forward would make length *appear* longer even though it would be *measured* shorter). However, the subjective experience of time would not change. The outside world, viewed by the being, would appear to be going very fast, so by that perspective yeah, the being would see "time slow down". But its thoughts and movements, from its perspectives, would not change. A fascinating Youtube video was made on this very topic: <https://www.youtube.com/watch?v=udqihUBGuZ8&ab_channel=TheActionLab> [Answer] ### The rest of the universe would be moving faster around you. You couldn't do this on a planet because you'd be clear of the planet faster than you could blink. The base time frame would appear to you to be more than seven times your time frame. If you had a telescope and were approaching a planet, it would look like eight times because you'd be seeing events that happened in a decreasing amount of the past. However, everything would be "foreshortened." Stars that you passed would look like pancakes, adjusted by the same 7:1 ratio that time was adjusted by. [Answer] The speed of light is badly named because that speed is the limit on pretty much everything. I like to think of it instead as the speed of causality. As for what it would likely see, think of it this way: If you started running forward and one of your friends was in front of you and started running perpendicular to you, they would catch you only if they were faster or the same speed. Most things you interact with would work the same way. The faster you travel, the less things can interact with you because by the time they get there, you're gone. If you are going a significant fraction of the speed of causality it's likely that what you "see" would be altered a bit. As mentioned elsewhere here, stuff in front of you would start to look bluer and bluer in to indigo, deep purple and then push on in to the UV range and beyond. Light coming at you is having its wavelength reduced because you're getting there faster. If this was a biological creature, it would need to be able to see very high frequency EM to steer at speed. It should be able to see radio, microwave and well beyond. It may have a multiplex eye with different parts for different wavelengths or different sets of eyes that work in different ranges. If it always kept its eyes open, inhabited planets and ships would look like a disco ball of various types of radiation. It wouldn't feel time moving faster or slower, however whenever it slowed down to non-relativistic speeds, it would discover that way more time passed for everyone else than it. Time and space are like the numerator and denominator of a fraction in a fixed ratio. If you have 1/2 and want to double the numerator, but also keep the ratio the same, the denominator needs to double as well. Moving through space slows down your movement through time and vice versa. While moving at high rate time is ticking slower for you than everyone else. You don't feel it because to detect something there has to be a difference. The reason a ruler works is that you can hold it up to something of a different length. If everything was the same length, a ruler wouldn't help, or be necessary. Time affects all of you the same way whether you are moving through it faster or slower. This would however have interesting effects. It likely wouldn't have a strong concept of time. Time and distance are two sides of the same equation. It would need some other way to mark the passage of its personal time and experienced age. Maybe there are certain physiological changes (turning gray?) that demarcate their felt age. Maybe if they can see strong EM they can do a type of sight-based carbon dating. Watching the rate of radioactive decay (if it can see EM) in some object could tell it how much time the object (or creature) has experienced. If sentient, it would useful to be telepathic. Languages would change so quickly (in its experience) that it would never be able to keep up. Social norms and culture could also skew wildly after only a little relativistic time. These creatures would likely be fairly insular as they grew older, since everything passes. It would need very good sight, likely some type of precognition, in order to make sure it didn't collide with anything during a high-speed jaunt. If it is traveling close to the speed of light, it likely wouldn't have time to react to "seeing" something before hitting it. It would need some type of protection against contact with - anything at high speed. A tiny fleck of dust can impact with massive energy at relativistic speed. It would be very difficult to tick all those boxes biologically. This critter had to somehow need that ability to survive. To accomplish relativistic travel it needs to essentially be a god. It needs to be able to survive massive impacts, see nearly all wavelengths, be precognisant (likely telepathic if it needs to communicate with other species) and be able to generate massive amounts of power. The farther you get from the speed of causality the less these issues matter. [Answer] There is no relativity, special or general. In your story you dont have to assume that Theory of Relativity is correct. If you believe that the theory is correct then you also have to believe that reality is subjective. That for different observers a same object exist at different sizes. This is nut job. Look at "barn door" paradox which refutes Theory of Relativity. Its roughly like this: suppose we make a barn or any container exactly as big as what it to contain, say a train. So, if we close the doors at 2 ends train fit exactly inside. "Exactly" here means with say 1 ft or 2 ft whatever extra capacity in the barn. Now, if Theory of Relativity is correct then as the train approach light speed it gets contracted for some observer and stay at its original (rest time) size AT THE SAME TIME. So, one observer sees it fitting exactly in the barn and with the doors closed. Another observer see it longer than the barn so its coming out of it at both ends. Here is the fun part, this observer also see the barn doors closed. He see no damage to the door and no damage to the train. The doors are closed yet the train extend beyond the doors. There are many other paradoxes as well as this one. They all refute the Theory of Relativity. What do happen is an illusion. Like a broken pencil in water. Just a mirage. The pencil is not broken. First 400 milliseconds after big bang, universe expanded millions of times faster than speed of light? How? Now they fool you by saying that space expanded. What? Space by definition is empty space. Vacuum. Nothing. How can nothing do anything? They will say that the first 400 milliseconds after big bang universe expanded so fast that there are parts of universe you can never reach even if you travel at speed of light or even ten times that because some parts of universe right now are going away from us thousands or even millions of time faster than speed of light. What? Didnt they said that speed of light is the ultimate speed limit? How can you distinguish matter moving away from each other from space expanding. If 100 airplanes hovering above ground in square formation with equal distance between them, say 1 km, move in such a way that they double their inner distances, you know by the planes at edges moving away 10 kms, the ones behind them 9 kms and so on, they will say that its space thats expanding, not the planes that are moving. Show them the fumes of burnt petrol. This is worldbuilding site, not physics site, you dont have to take Theory of Relativity as granted. You can write your story as you see fit. The point of this answer is, OP, that there is enough ammunition to refute Theory of Relativity. Logic do. Proof by Contradiction do. People that believe in the theory do so by dogma, not by logic and not by any science. They will say "there are many experiments" but not go in detail of any experiment, because you know, they dont do science. They do theory. You can "proof" anything in theory. You are now aware of existence of very logical and very scientific minded audience that actually do science. You can write story for them. ]
[Question] [ I have a character who wears a high-tech helmet with a high-powered laser mounted on it. Basically, the wearer “stares” at a stationary victim, and the laser is activated. The laser would take a short time (ideally a couple of seconds) to impart enough energy to cause the victim to explode. A few obvious issues- the helmet would need to be massive and unwieldy, it would require an absurd amount of power (which would preferably be carried by the wearer), and the user is effectively staring directly at the beam’s reflection. (I’m planning to address the final point somewhat by making the wearer already blind.) The wearer only needs enough juice to fire once or twice, but I’d suspect even that would require an extreme amount of energy. The wearer is willing to dump huge amounts of resources into building this helmet, but physical limits are physical limits. Best case scenario, the helmet wouldn’t be much bigger than a motorcycle helmet, and the entire system (power and laser) would weigh less than 100 kg. This seems a bit optimistic, though. This question may be too technical, but is it possible to make this work with semi-futuristic technology without making the wearer look like MODOK? [Answer] > > The laser would take a short time (ideally a couple of seconds) to impart enough energy to cause the victim to explode. > > > I have seen an industrial IR laser, used to vaporize metal, with laser power of several kW. It has a footprint of several tens of square meters of machinery and needs a hell of power and utilities supplied to be generated and amplified, and when fired on a chicken breast it carves a nice, round hole in it within seconds, but it doesn't make it explode. To have an explosion you would need the laser to be absorbed inside the body and vaporize enough water to build up pressure and cause the subsequent explosion. The closest thing to achieve this goal would be a microwave laser, basically a microwave on steroids. But I highly doubt it would be anywhere close to something portable and handheld by a single soldier. [Answer] I have worked with lasers that are used to cut and bleach jeans pants. They were in a power range much below what you need for a human exploder. They also needed large cooling systems, the kinds that have pipes running cold water. Your laser helmet would require a connection to a cooling tower bigger than you just to keep you from cooking yourself while shooting. As an alternative to your design, the helmet could be physically separated from the laser cannon. You stare, and a car sized thingamajib shoots at what you are looking. This way you only kill your victim, besides making it more feasible to power the laser. [Answer] #### Been There Done That Got the Laser Safety Goggles The system you describe has, in form if not in power, existed for decades. Ophthalmology surgeons sometimes use a head mounted laser where the power and lasing machine are in a little box and a waveguide brings the energy up to the helmet and sends it out to the target. These systems have two lasers, one generates a visible aiming beam and the other a visible or invisible death beam. Your user doesn't have to be blind, he just has to take standard laser precautions, such offering eye safety goggles to all his victims and announcing to them whether his laser is "on" or "off". At present, the boxes are light, and some even run on batteries. Obviously these are rather low powered. Since you gave us the power of weasel words, *semi-futuristic technology*, the only real problem is that of power, which you'll solve in another question about miniaturisation of power components! The helmet itself doesn't have to be heavy: the laser isn't mounted on the helmet, it's in the backpack. Even five to ten years ago you could buy on Ebay a small battery powered laser strong enough to light matches and pop balloons. Time marches on. Probably your kids will be able to buy one these death lazers third hand on Ebay in 15 or 20 years! [Answer] **To complement the other answers, the power for your HKS (Helmet Kill System) can be provided chemically:** The Hydrogen fluoride-CO$^2$ (or deuterium fluoride-CO$^2$) laser is used, producing a wide range of wavelengths simultaneously. Tantalisingly the Wikipedia article doesn't exist yet for that specific type - but [the reference](https://en.wikipedia.org/wiki/Chemical_laser) states that several megawatts can be produced this way with just a couple of little gas-tanks to feed the reaction, like Uncle-Sam's beer-hat: [![Picture of Uncle Sam beer hat.](https://i.stack.imgur.com/rwbEC.png)](https://i.stack.imgur.com/rwbEC.png) Copyright unknown, [Teesforall.com](https://www.teesforall.com/uncle-guzzler-p-40472.html) (commercial link, no affiliation), fair usage 2022. [Answer] # No One of the big problems with energy weapons (like lasers) is thermal blooming. As you increase the amount of energy in your laser, the air (and particles in it) will absorb a portion of the energy, and when it does, things in the laser's path will change phase and become better receptors of the energy, so the laser ends up blocking itself to some extent. The problem gets worse if it is foggy or smoky. The only solution is to fire it in a vacuum, or in exceptionally clean air. Additionally your laser is going to take more power than any 100kg source can currently produce, your future is going to need a lot of advanced mobile power solutions to make this feasible. [Answer] It's probably be easier to attach a mind control system, and then have it slice them apart. Just as deadly to anything but a flatworm, too. Cutting lasers require about 80 Watts of electricity. 10S LiPo batteries get us over 300 in just over 2 kilos (5 pounds). Power, check. The rest of it should be straightforward, attach one of those and a laser device to a bike helmet, and the problem is solved. The mind control and computer system can be installed semi-easily to the inside of the helmet, and weighs next to nothing. This system weighs around 10 pounds (4.5 Kilos) plus the bike helmet itself and the attachment setup (Duct Tape?). (Also, a laser can make someone explode. It heats up the water in their cells, and then the steam makes them blow up with the same concept as a water heater bursting. For that, just add a bunch more LiPos.) [Answer] ## Blinding The reflection doesn't need to be a problem when using pulsed lasers: tune some kind of shutter (can be LCD, mechanical, or something else) to the pulse speed so it's closed whenever the laser fires a pulse. The drawback is that your vision will flicker somewhat. ## The laser As for the laser power: as many others already mentioned, it just doesn't exist yet in that form factor. But what *could* work is having all the actual lasing be done somewhere else and have the helmet work as a beam guiding device. You have a few options then: * The helmet is a targeting device, using some low power laser to designate a point. The main laser will target that point with its big laser and fry the target. * The helmet is a focussing device. The big laser points a beam at the helmet which uses some mirrors/lenses to focus it on the target. To improve coverage put the big laser in a lighthouse-like structure, or for indoor use add exit modules for the laser in all rooms. [Answer] I don't think recoil is the main reason we don't attach firearms to helmets. Your proposal would be harder to aim accurately than a rifle is, unless the gun protrudes forwards enough to be visible to the user. Our idea of "staring" straight ahead doesn't seem precise enough, nor do our tolerances for angle disturbances when fitting a helmet. [Answer] ## This is more or less doable with modern technology [![enter image description here](https://i.stack.imgur.com/Nd8DN.png)](https://i.stack.imgur.com/Nd8DN.png) I read a US military study on this subject a while back that claimed, it takes a 1KW High-Energy Laser (HEL) to kill a person faster than they can get out of the way. It won't make them explode since that is not how lasers work, but it will burn into them causing surface level charring and raises their internal temperature enough to cause internal organs to boil and rupture. Modern military laser systems like HELLADS weight about 5kg per kilowatt of power meaning that using military technology that more-or-less exists today, it is not unreasonable to assume you can make this a hand held anti-personnel laser. That said, 5kg is a lot of weight to put into a helmet; so, instead I would mount this weapon on the back or shoulder and just ware the control mechanism on your head... basically giving you a weapon system very similar to Predator's shoulder mounted laser. There are also newer styles of Solid State HELs that are more scalable the Liquid HELs that are being developed for use on drones right now which may actually be light enough to ware on a helmet, but their exact specs are not public knowledge. Regardless, HEL technology has advanced so fast in the past 15-20 years that if you are planning for an even sort of future tech scenario, then an anti-personnel helmet laser is not at all unrealistic. The only unrealistic part is the person exploding. As for flash back, there have also been recent military research into "dark" lasers that reflect back self canceling wave patterns (kind of like how noise canceling headphones work) to significantly reduce how bright a laser strike is. Or you could just use protective goggles that filter out the reflected wave lengths since you don't seem too concerned about blinding innocent bystanders. ]
[Question] [ Our world orders the immaterial realm, a place in which daemons and otherworldly creatures reside. These separate realms have their own rules governing their realities, such as gravity, physics, and the laws of magic. However, there are certain places in which these worlds overlap and intersect with each other. Within these places, transmutation circles can serve as a gateway between worlds, allowing one to communicate with beings on the other side. A transmutation circle is a sigil or sign for a specific magical purpose, combining a complex combination of symbols and text to perform spells and rituals. When the proper requirements have been met, a mage can activate the circle using his own mana as a power source to fuel the spell. This opens up a connection with the immaterial to create a gateway linking both worlds. This gateway operates as a small pocket dimension that exists within the material world as its own pocket of reality. Within this reality bubble, mages can summon daemons and bargain with them in daemonic pacts to gain powers. The daemon within cannot cross the border of the circle, keeping the user safe from any danger posed by the creature. Powers given by daemons take the form of boons, powers granted by deities to mages that are meant to be beneficial in return for service to said deity. They can take the form of specific powers or access to magical spells unique to the deity. Daemons grant these boons to their followers to pursue goals on their behalf on the mortal realm, or as a gift in return for some service performed by the mortal in the hope of future cooperation. However, as the spell is only fueled by the mage's mana, it can only last for so long until the gate has closed. once the spell has ended and the connection between both realms is broken, the daemon is sent back to the immaterial. As the rules of host reality reassert itself, the power that the daemon had to influence the mortal world is lost. Any boon given to a mage should be rendered null and void due to it being incompatible with the material verse. How can a mage continue to use their newfound abilities when the daemon is no longer able to reinforce their end of the bargain? [Answer] ## Magical Focus A common element of mage-craft is the use of a Focus. This typically takes the form of a Crystal Ball, or a wand, or a staff. The form doesn't really matter that much, essentially it's an item the magic-user draws power from or casts their own power through for greater precision or potency. In your world, the Focus is created specifically to act as a physical link between the Daemon (in its source of power) and the Mage's world. You could think of it as a Transmutation Circle in a portable format. So by this pattern, the Mage's bargain with the Daemon is essentially an exchange of contact information and an agreement of terms and conditions. The Daemon ritually links themselves to the Focus in an intimate way that provides the Mage with access to their power. Perhaps by sharing some or all of their True Name. Once that task is complete, the Daemon can go back to its own realm and the Mage can call upon their power whenever they choose via the Focus. [Answer] **Instantaneous Magic** Demon Booms work by temporarily changing the rules for reality. For example a Demon alters reality around someone so that injuries heal much faster. The target's mangled arm quickly heals into a working arm. The Demon then leaves and reality reverts to normal. Does the arm go back to the mangled form? Nope, why would it? Now it is just a normal healthy (nonmagical) arm, and the usual rules of reality allow those. The demon changes reality so that centipedes are spontaneously generated. Loads of bugs appear. The Demon then leaves. Do the bugs leave? Nope, they are just plain ol' nonmagical bugs. The only magic was the magic that brought them here. The demon changes reality so that a piano appears above my head. I go splat. The Demon then leaves. Do I get better? Nope. Now I am just a splatted person. The demon changes reality to increase the size of the mana resevoir in Gerard's head. Gerard can now hold twice as much mana. The demon then leaves. Does Gerard go back to normal? Nope, this is similar to the arm example. The mana resevoir is not itself magical. All demon boons work like this. They create changes. They do not create continuous effects. [Answer] **Devil's mark** In folklore daemons often take souls in return for the powers they give, I understand that in your universe servitude is the price of those abilities, but maybe daemons take some part of the mage as a collateral. This part stays in possession of the daemon in a neighbouring realm making the mage into a kind of strained Reality Intersection, which allows daemon to keep tabs on the mage and give them it's power. This could also allow other people to recognize if the mage made a pact with a daemon, because reality could slightly break around this person i.e. they would be affected by a mix of rules from both realities they exist in, maybe they would cast shadow towards sources of light or everything would be lighter around them, depending on what rules apply in daemon's reality. This would be titular Devil's Mark. Hope i helped. [Answer] ## Brand the mage with a 2-way transmutation circle to seal the pact While the transmutation circle created to summon the demon is one-way and in the total control of the mage, this second transmutation circle can be opened by either the demon or the mage using either one of thier powers, and it is forever burned into the flesh of the mage so that it can not be easily removed. This way, the mage can open the link whenever he needs to access the demon's power, but the demon can open the link whenever he needs to check up on the mage to make sure the mage is honoring his part of the deal. If the demon ever opens the link to see the mage is not honoring the deal, he can use the link as a conduit to project his power through to punish the mage. Since part of the question is about enforcing the contract, the demon has a vested interest in NOT giving the mage a transmutation circle that can just be thrown away when the contract stops being in the mage's best interest. By making it a part of the mage's body, the demon is guaranteed oversight over the deal. *As a side note: [4dam's Devil's Mark](https://worldbuilding.stackexchange.com/a/227050/57832) answer has some very good ideas about stuff you can do to make a branded character more interesting, even if it does not actually answer the core of the question about how to make the contract enforceable across realties. If it were me, I would work some of those ideas into this such that the mage might be able to figure out when the demon is watching when the laws of nature around him start to subtly shift.* [Answer] # Have cults to power them. When the magic runs out, the gift dies. As such, never let the magic die. Any magician who summons a daemon will make sure to have a group of fellow mages and cultists to back them. They can use their shared mana pool to sustain the gift long enough to enact whatever wills they have. While communing across dimensions is immensely hard, powering a spell is much easier and relatively low skill people can be used to fuel it. Daemons will need to carefully select their gifts to be within the ability of the mages to supply enough power. Too large a gift will quickly drain the cult dry. Some daemons also engage in parasitism, adding secret spells to their main one that consume some power to enact their will or gather up power for future communions. [Answer] Ever read the Discworld series of books? There are tons of material on demonology there. Some songs were made for the books, and one of them has this in the lyrics: > > *The staff of a wizard can hold many spells > > For finding lost objects and dowsing new wells > > For banishing demons to bottomless hells > > And bringing them back on demand > > And bringing them back on demand* > > > I think the last couple verses are what you're looking for. Alternatively never banish the little bugger, just keep it in a jar. [Answer] In fact, daemons provide something that cost nothing in their world. Same for mages: they give mana (which will be restored in couple hours) and get something special. The real problem is to connect each other. That's your transmutation circles are actually do - like online marketplaces connect customers and freelancers. Circles are designed for immediate contracts but hey - you could want to work outside this 'magical Upwork' (to cut off intermediary's expenses and expedition costs). It will break the rules - but who cares? You agreed with daemon that **when you send some energy to that special amulet the daemon would decrease the gravity around it**. Of course, such amulets also breaks the rules (some legal, couple physical and dozen of magical) but again - who cares? Actually, this ***amulet is just better version of transmutation circle***. Who crafted it and why the Mages Guild conceal fact that it's possible to connect with daemons without circle - this is a good story for Part 2. In Part 2 you'll also know about those 'who cares' and what they do if catch cheater. The idea was borrowed from [short story](https://bormor.livejournal.com/576978.html) (original is in Russian. Probably [automatic translate](https://bormor-livejournal-com.translate.goog/576978.html?_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=ru&_x_tr_pto=wapp) would be good enough. Disclaimer: I'm not author of this story.) ]
[Question] [ In a fantasy world I am creating, there exists a race of elf-like hominids that exist along side other races in this world. Note the "elf-like" portion as while they do have: * Pointy ears (which move like a cat) * More prone to injury * Better eye sight * Better sense of smell * Slighter build * Faster and more agile * Slightly worse endurance * Around 152.4 cm (5ft) to 155.448 cm (5'1ft) These elves also have: * Digitigrade legs * Claws on the hands and feet * Strong grip * Run and walk in both a bipedal and quadrupedal stance * Mane like hair that extends down the neck and lower back (other wise naked like us) * Sharp teeth to accommodate purely carnivorous diet. As you can imagine, these guys aren't exactly your typical elf. And you especially do *not* want live near the ones that have no qualms with hunting down other races for food. My question is **what evolutionary pressures could lead to a hominid to evolve these characteristics?** Note: Elves are descended from hominids. [Answer] Lack of vegetable/fruit matter foods for long enough would do the trick when it comes to making them more carnivorous, probably due to desertification or something along that line making their native habitat worse to live in for herbivores or omnivores. They'll likely be scavengers for a while before moving on to more aggressive predatory behaviour and actively hunting things. The sandy kind of desertification will not lend itself well to the development of digitigrade legs, so instead of it turning sandy let's have everything turn into a rocky/craggy wasteland from an environment that used to be mountainous and forested but are now simply mountainous and rocky with little to no plants. You'll need the hard surfaces for the digitigrade legs to provide any significant advantage over not having them. Claws and sharp teeth will be gotten from the natural tendency for carnivores to develop natural weaponry, while the eyesight and smell and hearing and ear adaptations will also follow suite due to them needing to be better at tracking and spotting prey and scavengible corpses. The more prone to injury part is typical of carnivores, I doubt carnivores walk away from attacks without at least a scratch or bruise somewhere, only on these things they'd be more noticeable due to the no fur part. Them becoming faster and more agile will also be typical of predatory adaptations, but why you'd want them to have less endurance(stamina?) is beyond me. Perhaps you want them to be REALLY fast like a cheetah but those speeds naturally come with overheating drawbacks. Strong grips come naturally from primate hands, and because they've probably already adapted strong grips for tree climbing beforehand, but these will be further enhanced due to the rocky mountainous areas requiring a lot of climbing and jumping around(where the digitigrade legs will come into use quite nicely). For their running and walking to be functionally capable of both bipedal and quadrupedal locomotion I'll recommend that the length of their arms increase to make it less awkward with their behinds in the air due to the longer legs(it'll also help with climbing to cliffs and attacking). The mane-like hair is typical of mountain-dwelling primates, no need to engineer specific circumstances for it to come about, though why they still remain naked for the rest of the body you may have to hand wave as it'll get rather cold in this region at night. Might require many caves for shelter from the winds or penguin group warmth behaviour(assuming they don't develop clothes). [Answer] Your elves look a lot like [bears](https://en.wikipedia.org/wiki/Bear#Evolution), with the only difference that they are not plantigrade (which explains also their agility and endurance). I therefore guess that similar evolutionary pressures and circumstances which lead to the evolution of bears could, if applied to an early ancestor from the hominid branch, lead to the development of your elves. In particular they should get a strong advantage by being totally carnivore, while the bears are omnivorous. [Answer] # *Pure* carnivory is uncommon, and its rapid evolution needs a special reason [Six percent of a wolf's diet is plant matter and berries](https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.503.9779&rep=rep1&type=pdf). Here's a [cute video of a crocodile eating a pumpkin](https://www.reddit.com/r/Awwducational/comments/papk5b/despite_being_obligate_carnivores_crocodilians/). Here's a (self-described) [review of the top seven vegan dog foods](https://www.dogloversdigest.com/dog-food/best-vegan-dog-foods/). Also, at least thinking of land mammals, to be a "carnivore" means to tear indiscriminately at the something's innards, and to develop some tolerance for the deteriorating remains of a past kill. As a result, carnivores tend to moonlight as scavengers, and can consume the scats of other animals. For something to evolve *pure* carnivory, it means there would have to be some fitness cost to even *sampling* vegetation, so that even the thought of consuming non-flesh would evolve to become revolting, perhaps through a reworking of the innervation by olfactory neurons expressing particular odorant receptors. This means that the plants are not merely inedible - they are actively *toxic* to your 'elves' in a way they couldn't evolve to deal with. Or perhaps there is some pathogen that cycles between the elves and plants the way pork tapeworm cycles from pigs to snails. Becoming facultative bipeds, parabolic ears, clawed hands, strong grip ... these tell a story, where a prey animal (perhaps a small primate) can be heard venturing down into the low branches of a tree, and they stealthily sprint and stand to drag it down and kill it right away. If it moves they can run on two legs to follow. They may be able to follow by climbing into the tree, but their quarry is apparently rather agile also, and this can't be a substantial aspect of their behavior or they would have better fur or tougher hide to deal with a charge into branches. They likely live in areas with a large number of such trees, and explore large regions before waiting in ambush, accounting for their keen sight and smell and "slightly worse endurance". (*Some* humans, certainly not me, are the world champions of endurance, and can capture or otherwise make use of horses simply by running after them until the horse wears out: "persistance hunting". So the species you describe still has exceptional endurance by carnivore standards.) [Answer] **Savannah Elves** The elves are descended from an arboreal omnivorous species of forest-dwelling elf-monkeys. Being omnivorous the monkeys could eat fruits and seeds but not leaves, twigs or grass. They also ate small mammals, eggs, insects and such. Their sharp teeth were good for eating meat and sufficient for eating everything else. They did not for example need specialized grinding surfaces since they didn't eat grass or leaves. Claws and digitigrade legs explain each other. Since they did not grip with their back feet like normal monkeys, they need claws for climbing. Their slim builds and agility were good for getting into the high treetops. Their strong grip was good for climbing. Either the climate changed to make the forest a Savannah, or they simply spread outside the forest. Either way the Savannah has loads of grass which the elf-monkeys cannot eat. But it also has lots of grazing animals the elf-monkeys can eat. Thus they eventually specialized towards a carnivorous diet. [Answer] Humans tend to eliminate, or at least marginalise, predators in territory they control as a matter of calorie competition removal. This leaves a number of potential carnivore niches that aren't filled in our modern world because we maintain pressure to keep them closed. However if the dominant hominids were as evolutionarily advanced, and shared our aversion for competition, but were universally severely [night blind](https://en.wikipedia.org/wiki/Nyctalopia) they would still put the same pressure on purely instinctual carnivores through hunting and setting traps for predators on their lands during the day. They would then leave a niche open for a nocturnal hunter that was as smart as they were, able to go undetected during the day and slip through the defenses at night. Nocturnalism itself would create pressure on hominids to go carnivore if we assume a relatively human sensory suite too. We have very poor colour vision in the dark which makes determining vegetation characteristics like ripeness difficult to impossible, and telling potentially poisonous fungi apart equally challenging, meat becomes the safer food option. [Answer] Your elf-like hominids sound very feline: pointy ears, less robust (more prone to injury, slighter build), sharp eyesight and sense of smell, faster and more agile with less endurance, digitigrade with claws, carnivorous with sharp teeth. This could suggest that historically, they were be quick ambush pouncers like cats rather than endurance chasers like wolves or humans. The strong grip and optional bipedal stance could be the result of evolving to make and use tools and hand weapons. A mane could evolve as a flamboyance for attracting a mate and/or to protect the vulnerable neck when fighting (for a mate or when taking down a prey animal). So why both claws and a strong grip? Do they have a long childhood before reaching an age of intelligence during which time they have to fend for themselves? And develop greater grip as they reach an age of greater complexity? The grip itself could be used as a sign of maturity. ]
[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/215322/edit). Closed 2 years ago. [Improve this question](/posts/215322/edit) Why would electricity be needed to provide protection to the user of a suit of power armour? I'm not referring to the movement or any other systems in the armour. I mean, if the user gets shot, stabbed or otherwise physically attacked power is used & needed by the armour to protect from this attack. Why would this be the case? There is near future technology. It can't just be energy shields. [Answer] Your armour functions like **ERA In Space** ERA usually stands for [explosive reactive armour](https://en.wikipedia.org/wiki/Reactive_armour), a subtype of reactive armour. Currently seen on tanks, ERA comprises of explosive blocks that detonates outwards to counteract the impact of a weapon. In the case of ERA, the energy is already pre-stored in the explosives. However, your power armour could function as ***electric** reactive armour* instead, as described in the Wikipedia article linked. The external layers of your armour would be constantly electrically charged, and require a power supply as a result. Your suit of armour could also use a directed energy solution like lasers or a cutting torch directed outwards as a form of active protection system to intercept incoming attacks. Naturally, those would also require power to function. Just as importantly, behind the aforementioned defensive systems, there are computers running software that govern their function and are necessary for their operation. Unsurprisingly those also require power. [Answer] **Electroshapable material** Electroshapable material is material that can be shaped when an electric current is flowing through, while rigit otherwise. The inverse of this also possible, but I can't find the correct word for it. It is experimental and not for use in body armour, but with near future technology it might be possible. The idea is simple. You want your soldiers to have as little obstruction in manipulation. Soldiers need to manipulate the environment, like moving from one wall to another, aiming or pulling the trigger, to be effective soldiers. Enter the inverse electroshapable material. It's flexible when there's no current through it, giving maximum mobility to your soldiers. But on impact this can change. The impact of a bullet will start pushing the material. If the pressure is high enough a circuit will be completed, making the material rigit. All further energy of the bullet bill is canceled by the electricity. Power armour might be more like bulky big suits of metal. Yet here it can still apply. It might look big and intimidating, but good inverse electroshapable material can seriously reduce weight and increase flexibility. Your armour is essentially electricity, though some wear and tear of the material is certainly to be expected. [Answer] ## Mundane answer: climate control The suit is made of hard stuff over softer padding, all mundane materials that do not need electricity because the same design has been in use since Ancient Greece. But it covers the body entirely, without any gaps or weak points. That means that it quickly gets *hot* inside. A vein system of coolant runs through the lower layer, just like modern space suits, but that system of course needs power to function. You could wear it with an empty battery and be protected, but unless you are in Siberia, you would quickly suffer a heat stroke while doing so. ## More sci-fi answer: [piezoelectricity](https://en.wikipedia.org/wiki/Piezoelectricity) The armour is made of a revolutionary but not unthinkable substance that's soft like jelly for most of the time. It is barely a centimetre thick and fits over the wearer like a second skin, allowing for the same flexibility and range of movement as if the wearer had been in their birthday suit. It is covered in sensors that transmit sensations of touch, hot and cold to the skin underneath. However, when an impact is registred by those sensors, an electric pulse is sent out and the jelly temporarily solidifies in a large region around the point of contact. This distributes the force over a large portion of the body, in a nigh-flawless manner. Once the impact has impacted, it liquifies again and regular movement can continue. When the battery is empty, there's no current to harden the suit. Climate control would also fail without electricity. So without a full battery, the suit is generally useless. [Answer] **Air bags.** A problem with armoring a body against an impact is that the kinetic energy of the impactor is still transferred to the target. Frangible armor plates can absorb the impact but are then destroyed. Reactive armor meets the impactor with an outward explosion and is also then destroyed. Car air bags deal with kinetic energy in a way similar to reactive armor - an explosion inflates a bag of gas which is compressed, absorbing the kinetic energy. Auto air bags are also one use defenses and must be replaced after use. Your armor contains electric air bags. On impact by a hard surface (bullet, club) or shock wave (explosion), powered sensors deploy small air bags between the hard armor and the body beneath. These bags are inflated pneumatically and receive the energy of impact as compression, then deflate again. The compressed air charge held ready for inflation is renewed by electrical power but more importantly the detectors are electrical and without them the bags will not deploy. The armor will still work as a barrier when unpowered. Without power, the person wearing the armor will still not get cut by an edge or penetrated by a bullet. But that person will get bruised, and will have little protection against shock waves. [Answer] The armor protects the wearer from damages by astonishingly quickly repairing the damages it has taken, so that, by all means, acts like a brand new armor at any moment. This thanks to the patented NoMoDa$^{TM}$ (No More Damage) Of course, in order for this to happen, energy has to be supplied to the armor. Without energy it will quickly break and fail to fulfill its scope. [Answer] ## Polarized Armor Plating In the near future, escalation in material science either made ballistic armor so good that militaries have to switch to energy weapons or energy weapons got so good that they rendered kinetic weapons obsolete. To protect you from this new trend in high energy weapons, you need to magnetize your armor which would create a form fitting magnetic field around the user that will trap and redirect electrons, ions, and/or plasma around the user instead of hitting him. Covering a solider in always-on magnets would pose all sorts of complications; so, instead the armor uses electromagnets to only polarize itself as needed. While this may sound like just a variation of "energy shields" it is an actual technology that more or less exists today, we just don't have many practical applications for it since it is useless against kinetic weapons which is 99% of what we now face on the battlefield. [Answer] I don't know what exactly you consider 'near future technology,' but an armour could have its plates made out of a relatively flexible, ferrous material held in shape by electromagnets. Any dents or impacts are immediately counteracted by the magnetic force actively straightening the armour plate back out, requiring varying amounts of power. Alternatively, there's also an option of a material that gets deformed normally, but is able to form itself back into a predetermined shape and 'heal' when electric current is applied. ]
[Question] [ ## The city of Evermill Tens of millennia ago, a magician tried to reverse gravity in a 10km radius sphere around him for a dare. He succeeded, but unfortunately, the effect was permanent - earth, houses and hapless cows were suddenly inverted, eventually coming to rest as a lumpy dome floating in the air with a hemispherical depression beneath. The floating dome is buoyant, like an iceberg, and likewise free to rotate. Of particular interest to the city's eventual inhabitants was the edge - the local flip in gravity means that a flywheel placed on the edge would rotate forever, getting energy for free (see the blue bar in the diagram): [![Evermill](https://i.stack.imgur.com/IgVrr.png)](https://i.stack.imgur.com/IgVrr.png) The presence of free energy is noticed and exploited by the inhabitants, leading to a build-up of heavy industry: mills, blacksmiths, the like. Technology advances much more rapidly than it would otherwise. However, an industrial revolution - adjacent event has not yet occurred. The inhabitants of this city would likely think up a way to get through the middle of the sphere. Just jumping into the anti-gravity field would make you fall a kilometer up and likely perish, but it would be possible to carefully 'float' along the edge if you balanced the up/down pull carefully. You could build a tower arbitrarily high there, since higher stories would not need to support the lower ones. * The inhabitants have not discovered steam power. * Among the general population, knowledge of magic is limited to very simple spells - conjuring flame, altering oneself to look like a donkey etc. The fact that gravity has been inverted is no more remarkable/artificial-looking than the existence of a mountain. * Pretty much the entire edge of the sphere is populated, though some parts (near water, etc.) are denser than others. Transporting people and goods through the middle would be an obvious thing for the inhabitants to want to do. [Answer] We can choose to assume the earth-dome above is stable. It's not clear to me that it would be, but we can take it as given. Actually, we could also pretend it isn't stable and slides/spins/crumbles away. In either case, a possible solution for several problems is to ## build a geodesic dome along the boundary [![Geodesic dome](https://i.stack.imgur.com/mI228.jpg)](https://i.stack.imgur.com/mI228.jpg) (or whatever part of the boundary is not taken up by the earth-dome, anyway.) Let's break this into two parts. First, we'll ask what it would take to build this. Then we'll ask what it gives us. ### What would it take to make it? Not much. Normally, a geodesic dome needs to support its own weight all the way down, and would require all the engineering that would go with that. But Evermill's gravity-boundary gives us a unique situation: if the dome would begin to collapse, the parts of it that are pulled into the sphere of inverted gravity are immediately being pushed back up by their own weight. If it were built of rigid members, each of them that lies along the boundary would be pulled down and pulled up simultaneously--applying the torsional effect that will drive your free-energy flywheels--but also effectively giving each such member neutral buoyancy. And, in absence of external forces, they would tend to find that balance--in falling, more of their weight would lie in the inverse-gravity zone; in rising, the opposite. But we don't even need rigid members. We can build the dome out of ***rope***. 1. Consider a circular rope, running all the way around the boundary, at about 45 degrees up from the ground. If it can't stretch itself wider, then it can't simply fall down on the outside--it's not wide enough. Maybe it would fall down one side, pulling the other side up? 2. Well, then, anchor it with vertical ropes all the way around. If one side would come down, the other side must come up; but it can't because it's anchored. But wait...isn't the horizontal loop now bearing the weight of all the vertical ropes? 3. Nope. Or not for long, anyway. If the ropes were cut properly, to fit the distance along the edge of the boundary, they'll also get pushed up as soon as they begin to sag, and find a position of neutral buoyancy. 4. Since every part of this construction is supporting its own weight by straddling the boundary, you can add as many loops and verticals as you want...and the more mass you add, the more stable it becomes against the addition of the extra mass of (say) a person climbing up or down it, or any system of pulleys, or slides, or zip lines, or whatever transportation we'll eventually affix to it. 5. What we have now isn't really even a "geodesic" dome...it's just lines of longitude and latitude. Normally, this would be problematic, even for a stucture with rigid members...without triangles in the structure, the dome would be vulnerable to collapse by twisting sideways one way or they other. But, as we've already established, this dome simply can't collapse. And having horizontal ropes (or rigid members, up to you) will be advantageous, as we'll soon see... But there you have it. Technology required: Rope. Or wooden beams. And the ability to cut them at specified lengths. Method of construction is left as an exercise to the reader, but once you've got one rope to the earth dome, the second should be easier, etc. ### What does it give us? * **First and foremost, it gives us easy access to the underside of the earth dome.** You can imagine any kind of stairs, slides, firepoles, flywheel-powered elevators you like: the dome gives you a place to anchor them. If rope is too flimsy to hold your transport system rigid, upgrade the required parts of the dome to use rigid members. To go up, passengers take the inside of the dome. To go down, they take the outside. * **It also gives us a place to anchor more free-energy flywheels.** If you build a circle of mills around the base of the gravity-boundary, that's a fair start...but there's so much more free energy to gain from utilizing as much of the open boundary area as possible. With your pseudo-geodesic dome in place, you can install spinning flywheels on every horizontal member that isn't occupied with transport systems or other usage. Chains or ropes can be routed up the vertical members to transmit power. (Mechanical transmission of power isn't the most efficient, but whatever you get is still free energy...) * **Finally, this gives us a way to anchor the earth-dome**, if we'd rather it not rotate freely. I don't know what your plans are for it and what aesthetics you envisioned for Evermill, but at least on the practical side of things, maybe your commuters would like to have a reliable way to get to the same underdome-address every day. [Answer] Scale up the infinite-power flywheel into a Ferris wheel that spans the gap; passengers now provide power to the city when they enter or exit. Passengers should be lying down and buckled in, for safety during the flip; carriages should be well-padded. If the gap is too large for a Ferris wheel, build ramps up to the boarding-height on both sides, keeping in mind that counterweights crossing the border can reduce strain on the support structures for the ramp. [Answer] **First problem is lava.** After 10 km of the continental plate has been removed, lava appears at the bottom. This molten rock moves up and up in a field of reverse gravity with standard acceleration until it reaches normal gravity 20 km later. You can get a nice sub orbital fire fountain. In short - how is it possible that someone on this planet is still alive in the constant rain of lava? OK. lets say that there is much thicker continental plate or core of planet is not molten(need find how to generate magnetic field to not be burned by sun, but...magic?) Possible travel solutions: * gliders - can drop glider to sphere and glide to other side of sphere (and with right trajectory even to other side of planet) * big flying creatures like dragons can fly there. * magic - fly or levitation * magically enchanted ropes to make bridge (10km ropes are hard to make) Sphere shall be not static. It will be nice if it shrunk a little with any energy taken out of it. Maybe it take 500 years to drop from 10km to 9km radius but then "War of Sphere" can start and so another one and another... [Answer] **Pulley systems / Cable cars** If they have mills, they know about pulleys and gears. They have a flywheel that generates infinite energy and is perpetually moving. They can connect this flywheel to a pulley and gear system to continuously transfer material (and even people) to outside the boundary It would be a significant engineering project to construct the first stations both at the boundary and off the boundary, but once this is sorted, additional stations could be constructed with more ease [Answer] ## Travel along the edge They could travel along the edge. E.g. like so: Assuming they have wheels they could create vehicles that carry a large fan, similar to a windmill. This windmill the could lower to a 90° angle towards the sphere and use the propulsion to move forwards. Its a risky business and you would need to drive carefully to not fall into the sphere. Boundaries need to be static for this and well marked with streets e.g. [![enter image description here](https://i.stack.imgur.com/grF0M.png)](https://i.stack.imgur.com/grF0M.png) ## Travel in and out of the sphere You could travel in and out of the sphere by using artificial mountains where "Ground" and "Ceiling" come close naturally already (left). Or they could put long "bridges" (right) that balance out and allow to drive in an outside. [![enter image description here](https://i.stack.imgur.com/kEqIO.png)](https://i.stack.imgur.com/kEqIO.png) [Answer] ## Stay in the sphere There is no reason given why Evermill would have to extend beyond the sphere. While there would be problems, they should be solvable with the technology available: Water could be obtained through a canal, which would empty out into the sphere, and flow down in a waterfall into a reservoir Light could be provided by candles and all the other ways that people used to make light. Or, more exotically, the people of Evermill could have learned to live without light and vision Leaving the sphere could be a challenge. One simple yet poor solution could be cushioned tunnels, so that people could simply walk out of the sphere and fall onto the roof of the tunnel. A more magical solution could be a room hanging on a hinge, where a magic user could slowly flip around, allowing the users to safely turn their gravity around, before entering/leaving the sphere with a bit of extra magic to keep them grounded. Both methods could be used, with the room being a service accessible only to those with money to spare, and the tunnels being used by the average guy [Answer] To enter the sphere, you can use the same principle that powers your flywheel. Have a nice comfy chair inside a rotating cylinder centered on the boundary. When a passenger sits in the chair, release some kind of locking mechanism (I'm imagining a cotter-pin, but you could potentially have a bar that slides into place on the opposite side when pushed out of the first side) and the weight of the person will rotate the otherwise empty chamber so that the chair moves downward -- and toward the transition point. Once the chair crosses the boundary, momentum will make it want to continue in that direction, and then the flipped gravity will make it want to continue rotating until the passenger is right-side-up in the inverted gravity. Just put a stopper and/or brake in there, maybe a hand-crank so they can add some torque themselves if needed, maybe some comfort & safety features like seatbelts, shock absorbers, etc... [![enter image description here](https://i.stack.imgur.com/4svwv.png)](https://i.stack.imgur.com/4svwv.png) Note that this doesn't resolve altitude difference (unless it's *really* big), but if stairs don't work for you then you could take advantage of the fact that the border of your anti-gravity sphere is curved. There should be an equilibrium point along the border (yellow), so you could build towers (purple) on either side, and have pulleys (green) mounted on blocks (blue) that can slide up and down between them. As you pull the passenger car left and right, it will travel up and down along the equilibrium boundary. If your people are particularly good with geometry, then it would be more efficient to do this along two axes simultaneously. [![enter image description here](https://i.stack.imgur.com/5UNi2.png)](https://i.stack.imgur.com/5UNi2.png) [Answer] you are missing the point of gravity, gravity is a geometrical property, there is gravity only because we are in a sphere, gravity would behave differently in the photo you describe I suppose, just ignore physics and make up weird rules of your own, if you try to not ignore physics you will end up doing it wrong most likely. Don't mean to be rude, I meant to say: you have a lot of leeway to creating your own idea of how they commute without incorporating the need for the villagers to use magic. Saying something like: "they commute like: ..., because that's how it works in this gravitational field", should be fine [Answer] ## Man-lifting kites [In ancient China and Japan, these often seemed more a means of execution than travel](https://en.wikipedia.org/wiki/Man-lifting_kite); nonetheless, the technology was progressively refined. Given the motivation for travel here, and the mechanical advantage of being able to *lower* the convicted "explorer" to the ground inside, it seems like this could work quite well. Provided you have a few times more prisoners outside the dome than you need to have inside it. ## Never mind -- just JUMP already! There was too much rope in the last answer unless you have *really* good weavers. So forget the parachute! For a 10 km radius sphere, maybe 25 degree arc, there's maybe (1 - cos 25 degrees)\*10 km = 0.9 km horizontal displacement between the place you enter and the place you leave. If you run into that at 10 km per hour, it's going to take (60 min/1 h)(1 h/10 km)(0.9 km) = 5.4 minutes to move, horizontally, to any point where you can touch the ground. Vertically, you know where you'll be - the sphere. Vertically you'll move at (sin 25 degrees)\*10 km = 4.2 km in that 5 minutes, so your overall speed will be 52 miles an hour. But that's fastest at the start, where you're falling straight down, and slower near the end, as your horizontal momentum has been lost to some amount of air resistance. You'll definitely be rolling when you hit and hopefully you won't break anything important. Or you can skip the run shot and hope you eventually drift far enough to reach the ground, without getting torn apart by the spinning effect of the edge gravity in the meanwhile. [Answer] It would seem to me that the solution is not to go **down**, but to go **UP** (which would be 'down' for them). If the residents dug down, according to their gravity, they would dig through their 'land' and end up on the TOP of the sphere, relative to the rest of the world. Given that they are industrialized, and technologically literate, surely they would have developed an airplane that would fly them in regular gravity and 'normal' atmosphere down to the surface of the earth. Wen they wanted to return, they would fly back up to their 'hole' and then climb back up to their surface. I suppose eventually they would put an elevator in the hole, to make life easier for them. Going DOWN, err, rather, UP. ]
[Question] [ In my world, an event occurs in low orbit around the Moon that releases a tremendous amount of energy in the form of a conversion explosion and gamma rays pulse. Said pulse expands outwards and smacks into the hemisphere of Earth currently facing the Moon, instantly killing nearly everything in that area. The exact amount of radiation required to accomplish this is unimportant, as is the means to generate it. **My question is merely: is the end effect of this event - half of Earth instantly dead via a gamma radiation pulse - scientifically plausible?** [Answer] # Radiation: absolutely yes. But Gamma radiation is a bad fit. The atmosphere quite effectively blocks Gamma and X-ray radiation. Even ultrahigh energy photons are very well blocked by the atmosphere. By the time the radiation at groundlevel becomes dangerous, you are in much more danger due to the atmosphere above you becoming red hot+ from absorbed energy. But: **the atmosphere is only middling effective at stopping true Cosmic Rays. i.e. relativistic speed particles, mostly protons.** Actually the upper atmosphere *does* stop the incoming particles quite well. Unfortunately, the act of stopping them is like stopping a bullet by having it hit a porcelain cutlery set. You stop the bullet, but you are left with a huge number of shards, splinters and debris that now carry a part of the energy with them. If your disaster event around the Moon released not Gamma but high energy particles, then yes the Earth could suffer. Of Course, it would have to be an event of truly mindboggling magnitude, as the energy release will be non-directional, and the Earth covers only 1/32000th of the visible sky from the Moon's distance. Then, any energy that reached Earth is spread over the entire facing side of the Earth, some 250 million square kilometers. **As for "Instantly Kill"** If you really need to kill everything *instantly* then heat pulse is your only option. This is not a good idea, as I believe you want the other side of the Earth to survive? Instantly immolating half of Earth will kill the whole Earth within hours, as the heat will cause a shockwave to circle the Earth, scouring the surface all the way. If you just need to kill everyone on the surface *soon*, as in within an hour or so, that is much more achievable. Acute radiation poisoning, if severe enough, will cause cell membranes to depolarize, causing the nervous and respiratory systems to collapse. The dosage require is truly monstrous though, on the order of 50 time normal "lethal" dose. Figure 200 Sievert or more. If you can wait a month or so for the dieoff, you only need about 8-10 Sievert. This is the normal "lethal, no chance" radiation dose that kills in several days to about a month. P.S. No matter what the dosage, as the radiation is only in the form of high energy particles, the residual radiation will very rapidly fade down to reasonable levels. You would not permanently contaminate the whole planet unless your radiation pulse also included a lot of Neutrons. (In which case, bye-bye whole planet. for many millions of years) P.P.S. Except for residual radioactivity, the Ocean will be unaffected. Water is an **amazing** radiation shield to all kinds of radiation. The energy of radiation needed to sterilize the ocean depths would achieve that sterilization by explosive boiloff of the water, before the radiation itself is an issue. [Answer] ## Yes But... For a gamma ray blast powerful enough to instakill half the planet, the EM radiation levels required would superheat the atmosphere and everything else underneath, incinerating it all. It wouldn't be "radiation poisoning suddenly causes everyone to drop dead in their tracks, leaving everything else mysteriously unharmed", it would be a massive fireball roasting everything facing the moon. Also note that the side of the Earth opposite the blast will then have to deal with the *massive* shockwave caused by half the planet's atmosphere instantly being heated to nuclear fireball temperatures and all of the follow-on effects from that. There is going to be scouring winds, tsunamis, flashfires, and all sorts of other fun stuff like that. I'd imagine that the blast could strip off a sizeable fraction of the planet's atmosphere, depending exactly how hot things wind up getting. All-in-all, the people on the side facing the moon might be the lucky ones, given what the survivors on the other side will be left to deal with. [Answer] Since you are assuming gamma rays, let's give a look at the closest equivalent we have available: [atomic bombs](https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions) > > Energy from a nuclear explosion is initially released in several forms of penetrating radiation. When there is surrounding material such as air, rock, or water, this radiation interacts with and rapidly heats the material to an equilibrium temperature (i.e. so that the matter is at the same temperature as the fuel powering the explosion). This causes vaporization of the surrounding material, resulting in its rapid expansion. > > > I would say that it is more than enough to kill everything that happens to be showered with gamma rays. Incidentally, gamma rays are also used to sterilize items we deal with in our daily life. [Answer] # Nope Our upper atmosphere is practically opaque to gamma rays: ![A graphic showing the atmosphere's absorption bands for electromagnetic radiation. Gamma rays are 100% absorbed](https://i.stack.imgur.com/LuG5J.jpg) The Earth has even been hit by gamma ray bursts in the past. While there was damage to life, it was not in the way you imagine. [From the Wikipedia article on gamma ray bursts (which are stellar system destroying events):](https://en.wikipedia.org/wiki/Gamma-ray_burst) > > Earth's atmosphere is very effective at absorbing high energy electromagnetic radiation such as x-rays and gamma rays, so these types of radiation would not reach any dangerous levels at the surface during the burst event itself. The immediate effect on life on Earth from a GRB within a few kiloparsecs would only be a short increase in ultraviolet radiation at ground level, lasting from less than a second to tens of seconds. This ultraviolet radiation could potentially reach dangerous levels depending on the exact nature and distance of the burst, but it seems unlikely to be able to cause a global catastrophe for life on Earth. > > > The article does cite some long lasting effects of duch a burst, but nothing that comes close to what you wanted. ]
[Question] [ It was suggested that a medieval people, with a readily available source of electricity, would develop electric motors and horseless carriages. I had thought these would be too complicated to make until the 19th century. Benjamin Franklin discovered a primitive electric motor in the 18th century, but it wasn't until 1832 that it was usable for moving machinery. The power the medieval people would have are batteries with, practically speaking, unlimited power. They can set the voltage and amperes to whatever the like, up to a gigawatt of power. There are quite a few of these batteries around, left by aliens, so I wondered what they might develop with so much electrical power. [Answer] Sort Of. Making a ***thing*** that turns when power is applied is easy, if you have the power. Making a practical electric motor is a wholly different matter. Assuming you miraculously get a source of DC power. (supplied by aliens, it seems) You still need a working knowledge of electricity and magnetism. But, again, with ample power source and minimal copperworking skill you can achieve this through trial and error. Then you need to actually build the motor. This requires Steel (not iron). It requires low-friction rotational mountings. Bearings. Although you might just get away with a well-greased smooth shaft. And you need the ability and skill to make many,many,many meters of *consistent* thin copper wire that is also *consistently* insulated. Lumpy wiring or insulation leads to internal heating leads to motor burnouts. You also need small things, like working switches, reliable wire splicing methods(*not* just twisting two wires together, you need soldering). In developing your motors, you will most likely find yourself also inventing the portable, non-water fire extinguisher as an absolutely essential tool. ***In short:*** Yes, given a free power source you can build motors. They may not be practical for use without a strong supporting technology of tool fabrication, metallurgy, and assorted other sciences. [Answer] From <https://www.fleet.org.au/blog/spinning-wire/>: > > ![spinning wire](https://www.fleet.org.au/fleet_public/wp-content/uploads/2018/01/Spinning-Wire.gif) > > > When the wire touches the top of the battery and the magnet, it is making a circuit, which allows electrons to flow – this is the current. There is also a magnetic field present due to the magnet on the bottom of the battery. When electrons move in the presence of a magnetic field, a force is created that is perpendicular to both the direction of the flow of electrons (current) and the magnetic field. This force, which is called a Lorentz Force, acts on the wire and causes it to move, which makes the wire spin around. > > > This would be easy to discover if the aliens have also left strong magnets. In a strong magnetic field anything with current flowing will move. It doesn't have to be a wire and doesn't need insulation. From <https://garethladley.tumblr.com/post/166922851287/homopolar-motor>: ![homopolar motor](https://64.media.tumblr.com/1519f315a9cf282171455122dd004939/tumblr_oylsxkgwyM1tol09yo1_400.gifv) Without magnets the construction relies on a coil: <https://www.wired.com/2016/01/how-to-build-a-super-simple-electric-motor-out-of-stuff-you-already-have/> ![motor with coil](https://www.wired.com/wp-content/uploads/2015/12/simplemotor.gif) With an AA battery this would be hard to discover. It would run out and cannot put out a lot of power. But with an infinite alien battery? * Instead of thin wires, you can short circuit it with anything. Huge currents can flow, magnifying the slight forces that appear from incomplete coils (just a curved conductor). * The battery invites experimentation. It can melt metals without putting out heat. It can kill people. It can create sparks. I think they can do it! [Answer] Building a primitive electric motor isn't that difficult--it just requires copper wire, magnetic material, and some sort of insulating material like cloth. Even though it would be be almost prohibitively expensive, it could be done far earlier than the 19th century, although due to the lack of high-density magnets, it would probably not be very effective. Here's how you'd build one: 1. Draw copper wire. The less variation in diameter across the length, the better. 2. Wrap copper wire in glue and fabric to insulate it and then form it into the necessary coil(s) for the motor 3. If you want to build a DC motor, you'll need to build the graphite brushes too 4. Spin your magnet in the coil and you've got a generator, run power through the coil and you've got a motor. One of the major roadblocks would be the lack of permanent magnets. Neodymium was only discovered in ~1880 and modern rare earth magnets were invented in the 1900's. They would need to make extensive use of electromagnets and cumbersome lodestones if they can't find/synthesize magnetic material. The biggest challenge is battery technology, in particularly, energy density. Only very recently (circa 2010) did batteries become good enough for high-performance applications like drones and only just now (2020) are batteries becoming good enough to seriously compete with combustion engines. If you have alien-given battery technology, it is very likely that electric motors would be discovered far, far earlier. Many of the early electricity experiments struggled with the fact that to generate magnetic/electric fields that are measurable by primitive technology, you need a lot of electricity in the first place. For example, one of the earliest electromagnetic experiments was running power through a cable and then seeing how it affected nearby compass needles. People would presumably stumble across this much sooner if they were given infinite electrical power. [Answer] It's feasible, given the knowledge of what to do. Making, insulating, and winding the wire would be very expensive and manpower-intensive, and forming the shafts, bearings, etc would require some very specialized and very expensive craftsmen...things like standardized mechanical parts didn't exist before the industrial revolution, but the most exotic material you'd need is magnetically soft iron (wrought iron would work well), everything else could be brass, bronze, copper, etc. You wouldn't even need strong permanent magnets (you just need more of those expensive and difficult to fabricate coils). However, a generator is just as easy to build, and in fact the same device can work as both. Benjamin Franklin was entirely capable of building a generator that could produce useful amounts of electricity, and motors to use it...he just didn't know how to do so. Designing an efficient and useful electric motor or generator is rather non-trivial, and required advances in scientific theory and mathematics. These magic batteries would certainly help in developing electromagnetic machinery, but developing practical electric motors would still take a lot of time, and without an industrial revolution such machines would be incredibly expensive. They would also be difficult to repair, given the lack of standardized parts...you would need a craftsman capable of fabricating new parts from scratch. [Answer] **Frame challenge** This sort of question is quite common. It doesn't make a lot of sense in my opinion. Any society from the Ancient Greeks onwards (if not before) could have invented anything that we have today. All it requires is a stable enough civilisation which, in itself, is promoted by technological advance. Humans were intelligent back then and could understand all sorts of concepts. If they had this magical source of power, they could use it to make simple machines which could be used to make more complicated machines which could be used to make even more complicated machines ... All you do is shift the clock forward when exploring this sort of question. Medieval people would have been more advanced than they actually were. But so, what? If medieval people had lived in tower blocks and had iPhones, they wouldn't have been medieval in the sense we understand. You might as well construct a story in the modern world. I hope this doesn't come off as too much of a rant. My intention is to avoid too much repetition of what I consider to be a common but unproductive line of enquiry. [Could medieval age people have built a missile?](https://worldbuilding.stackexchange.com/questions/20208/could-medieval-age-people-have-built-a-missile?rq=1) [Is it possible to erect an electric fence in medieval period?](https://worldbuilding.stackexchange.com/questions/54197/is-it-possible-to-erect-an-electric-fence-in-medieval-period?rq=1) [How do medieval people fight if they can discharge powerful electricity?](https://worldbuilding.stackexchange.com/questions/170237/how-do-medieval-people-fight-if-they-can-discharge-powerful-electricity?rq=1) etc. [Answer] what they lacked is knowledge and a drive, a purpose, and in our real history those sweet sweet infinite electricity source, gifts of gods. in terms of craftsmanship, materials, and other necessities they were quite well equipped to the task(IDK, think of a clock, I bet u 99 percent do not know how they were made if haven't seen Click Spring videos), they just would not know how to put it all together. really, early bronze age technologies, and methods, and materials would suffice to build a practical electric motor. but also do not forget those famous examples that - rockets were known in ancient china and some conspiratologists/historians/MythBusters even tried some of those as weapons, which may or may not be used by Koreans(?) at that time, with low-end partial success. A steam engine, as a toy, was known since the roman empire/Greece, but it took half a millennia or more and a different civilisation to put it to work. There is a saying that necessity is mother of inventions, and it not necessarily mean u invent when the hard time comes, but rather one puts together what u already know in a solution which then being used, along u can invent few other things but. There are multiple examples of early births of ideas or prototypes which didn't take off until later time or died prematurely or had a hard time spreading. Bearings, wires, magnets, casting, insulation - none of that was a problem at medieval times. Heck, they even had conveyer approaches of manufacturing long before Ford made it a thing, again circa Rome empire time at least, the mass casting(mass production in some sense) was known even before them. what were they lacking is a system of systematic knowledge and problem-solving and knowledge proliferation en masse - which today we call science or scientific methods. So, could they - yes, absolutely; would they - unlikely, if not handwavium, batteries alone by far is not enough. But the scientific and industrial revolution could come a few hundred years earlier. Having a powerful electricity source you even do not need to use it in your typical electric motors to make a motor - start directly with ion engines, lol [Weekend Project: Ionic Space Thruster](https://www.youtube.com/watch?v=PvnF2bMnJtU) [Ion Propulsion - The Plane With No Moving Parts](https://www.youtube.com/watch?v=IorDYGI1uqc) or some turbine water combustion setup - electrolyze water and mix it with some water stream in a pipe and sparks inside and have u trusty water spitting pipe hitting water wheel type setup. as it quite easy to observe those effects, and the mechanically inclined mind can come with a certain setup. electricity is very powerful and flexible - the way we use it is not the only way, we try to use it efficiently as it is not free, but if one has an abundance of it and does not know better ways - there are a lot of ways of how to use it. **p.s.** about repacing horses, by the way, do u know what a replacement lacks of? Autopilot, and we still didn't solve that problem, lol. Yes, sure we had gotten plenty of perks by that relacement, too many to count, but autopilot was lost for a long time, until recent years. so even if u have motors, u have to put more benefits on a plate to convince others it is a good replacement. roads are bad, so u may forget about speed, lol. No lights on roads, forget about 24.7 driving, etc. railroads are good because they solve some of those, but it is good only where it is. ]
[Question] [ In a world without fossil fuels, would air travel ever really be developed? Without fossil fuels, the most likely path that could lead to the development of a proper industrial revolution would eventually be nuclear power and renewables. This world would probably start with hydro-electric power, in which they then move on to nuclear as scientists living in the cities that build up around dams are able to discover more about nuclear physics that would allow this to be harnessed as a fuel source. While there are other questions that could be raised, how would air travel be developed in this sort of world? Could airships remain viable in the face of electrified railroads and nuclear transport across oceans? Would fixed wing aircraft or helicopters eventually be developed? What fuel sources might they use? [Answer] ***Lighter than air craft:*** While the modern combustion-powered aircraft would be a hard sell, there were [steam-powered airships](https://www.space.com/16623-first-powered-airship.html#:%7E:text=Henri%20Giffard%27s%20steam%2Dpowered%20airship%20flew%20in%201852.&text=In%201784%2C%20General%20Jean%20Baptiste,Meusnier%27s%20design%20was%20never%20built.) built long before the Wright brothers, and hand-cranked *designs* existed before that. After that, electrically-powered airships were constructed like the [*La France*](https://en.wikipedia.org/wiki/La_France_(airship)). A steam powered model could certainly have been operational, utilizing charcoal or distilled volatiles, and in fact such designs predated ones using fossil fuels. Only the relative efficiency of fossil fuels caused them to predominate. In fact, the [diesel engines](https://en.wikipedia.org/wiki/Diesel_engine) invented by Rudolf Diesel initially ran on coal dust (easily a sub with charcoal) or vegetable oil, demonstrating that biofuels were already viable early in the history of aircraft. [Diesel aircraft engines](https://en.wikipedia.org/wiki/Aircraft_diesel_engine) were viable at the beginning of the aviation industry and are currently enjoying a resurgence. Once the value and efficacy of aircraft were established, I doubt they would have simply disappeared. It is speculation to say if fixed-wing aircraft and helicopters would have been invented, but I'm guessing that as the manufacture of biofuels for various powered vehicles became more common, they probably would have been at LEAST invented, even if they didn't end up being practical. The versatility of these vehicles would probably still have led to at least specialized functions for them. But I'm confident there still would have been blimps and dirigibles, and likely better ones than we have today due to lack of competition from gas-guzzling fixed-wing craft. Land and sea transportation also benefited from fossil fuels, so weaker competition in these arenas means the airship would have been quite reasonably competitive as a passenger and even cargo transport. You may find [this](https://worldbuilding.stackexchange.com/questions/67461/realistic-airships) question relevant to your question. [Answer] ### We were flying for [hundreds of years](https://en.wikipedia.org/wiki/Early_flying_machines) before putting an engine on planes: * We had man-carrying kites going back to possibly the 7th century. * 1783 we had manned hydrogen balloon flight. * First heavier than air craft (no human on board) was 1655 apparently ([spring powered ormithopter](https://en.wikipedia.org/wiki/Early_flying_machines#The_17th_and_18th_centuries)). * In 1853, British engineer George Cayley built the world's first real glider. With no petrol, the wright brothers plane as built couldn't exist (they used gasoline), but we had batteries and electric motors at this point in history, they have a lower power to weight ratio, but that first flight could've occurred electrically in the same period. Long distance air travel would be harder, batteries are heavier than the same amount of fuel, but lacking fossil fuels, we can still refine ethanol from biomass. There are [ethanol powered aircraft](https://en.wikipedia.org/wiki/Embraer_EMB_202_Ipanema), which are actually cheaper to run than gasoline ones. That linked one is commonly used for crop dusting, and can be powered by ethanol generated free from waste parts of crops. There's no reason that can't scale up to a small airliner-sized aircraft. [Answer] In Brazil "pure" ethanol (94% ethanol, 6% water) is sold at every gas station, and pretty much every new car sold can run with any proportion gasoline-ethanol mixture (they call it "flex" engines). So, the infrastructure for a fuel that can power a combustion engine for a heavier than air aircraft does exists independently from oil since the 1970's. The history would certainly be different, and possibly there would not be the political-economical incentives for airplanes to be what they are today, but it is quite possible they would be invented and be used for local travel in places where sugarcane is viable. [Answer] River-side mill towns existed before electricity could be used to export energy. > > Would fixed wing aircraft or helicopters eventually be developed? What fuel sources might they use? > > > sailplanes, definately. Oowered craft, maybe for military applications, and use by the very rich. They would probably be ethanol fueled, it's hard to speculate on which type of engine they would use. [Answer] ### solar wings Today there are experiments with solar- and battery powered electrical aircrafts. They work well enough! Though, to save energy, they fly slow. Get used to have a cruise speed of 300km per hour maxi. ### catapult start If you have to use less power, you can still fly. Most power is needed during take-off. Would it be a strong requirement that no fossil fuels are used, airports could have an aircraft-carrier-like catapult to help supplying a part of the energy. ### sailing In-flight you can be totally powerless with today's normal aircraft ( like Boeing 737, A350, Dreamliner, Comac and the like) and fly hundreds of kilometres without problem. That said, you will be even slower than the solar aircraft above, probably in the range of 100 - 200 km per hour, also you need some means to get them up there in the first place. If you build sailing aircraft specifically for this speed and purpose, it will get better. If you are ready to spend part of the flight time using convections to gain height, you can fly very very long without power, but your average speed gets even lower. Trains are better and faster then. ### hydrogen engine Today's turbines can be powered by hydrogen, too. On first glance this is even attractive because hydrogen has a 4 times higher power-to-weight ratio than kerosene. However the storage of hydrogen is so complicated that it will eat up much of that weight-advantage or even more. So imagine today's aircraft with a different kind of fuel storage, probably in the belly and not in the wing, so the wing can be slightly slimmer but longer, and you have that just-subsonic aircraft from today, but without fossil fuels. I don't know if we would have taken the same development path towards this fossil-free aircraft like here, on a world entirely without fossil fuels. [Answer] Not directly related to the fuel used in the aircraft, coal is also used to create coke which is used in the creation of metal products > > In 1709, Abraham Darby I established a coke-fired blast furnace to produce cast iron. Coke's superior crushing strength allowed blast furnaces to become taller and larger. The ensuing availability of inexpensive iron was one of the factors leading to the Industrial Revolution. Before this time, iron-making used large quantities of charcoal, produced by burning wood. > > > As other answers show fossil fuels can be replaced with other fuels. However the lack of easily and cheaply available fossil fuels would impact the course of the Industrial Revolution in your world impacting the availability of many technologies. Additionally the lack of fossil fuels means that the use of wood as a fuel remains high leading to higher levels of deforestation which can deeply impact a region's ecosystem. Japan managed to prevent deforestation by changing their use of forests (source: <https://www.appropedia.org/Japan_Forestry>). Easter Island, however, did not. > > With the loss of their forest, the quality of life for Islanders plummeted. Streams and drinking water supplies dried up. Crop yields declined as wind, rain, and sunlight eroded topsoils. Fires became a luxury since no wood could be found on the island > <https://rainforests.mongabay.com/09easter_island.htm> > > > Would Britain have avoided Easter Island's fate without fossil fuels to burn for simple things such as heat and cooking? A different approach to the use of wood and forest management would be required. Further impacting the course of industrialisation. Farming is also impacted by industrialisation, think of all the tools and machines. Further farming depends on fossil fuels for synthetic fertilizers (<https://en.wikipedia.org/wiki/Fertilizer#Nitrogen_fertilizers>). Considering the reduced farming efficiency means that large part of the population is involved in food production so there are less engineers and scientists for developing alternative methods for creating cheap metals, electricity generation, or even nuclear technology. The farming efficiency will also impact the availability of bio fuels. All that being said the Industrial Revolution would probably still be possible without fossil fuels but it's course would definitely be different. I can imagine that societies would try to find faster growing trees to supply their energy needs, maybe even bamboo which can also be turned into charcoal. Probably different furnace designs would generate cheap metals with charcoal or bio fuels. Electricity will likely start to play a role in metal smelting and refining earlier on as well, see eletric arc furnances for example. Once this thin edge of industrialisation's wedge is in the developments will continue. However the industrialisation speed and scale would be impacted by the need to constantly balance the environmental aspects to maintain healthy forests and farmland. Failing to do so would hurt a society without fossil fuels a lot quicker stalling their industrialisation. As laid out by others aircraft would be possible without fossil fuels. However the total energy available is simply more limited without fossil fuels. Most technologies, including railroads and flying would be less wide spread and thus available only to the rich elite of society. Hydropower is also a lot less available especially before Hydropower dams can be built, still being based on waterwheels. Wind power would be implemented more since windmills can be placed in more locations. Batteries would be a lot more important in this world dependent on electricity, as we start to see in the world today. Battery powered aircraft are possible but require more energy dense batteries than we have today. Considering the importance of batteries in your world these would surely be invented. I expect nuclear power to be a bigger game changer than in our world, making power available more cheaply at a bigger scale. Either that or wind and eventually solar power would play a bigger role. As for your question "Could airships remain viable in the face of electrified railroads and nuclear transport across oceans?" Probably yes, aircraft would still be faster than ships and trains generally can not cross oceans and seas. Also aircraft need less infrastructure than trains which I can imagine will be an even bigger advantage in a world where it less easy to mass produce many thing for a long time. Also don't forget the military applications that are unique to aircraft which will aid their development. [Answer] Piston and jet powered flight could still be developed without reliance on fossil fuels. We use fossil fuels for gasoline, diesel, and jet fuel because it's relatively easy to prepare from the oil we extract from the ground, the fuels are energy-dense and the engines are power-dense. However, both piston and jet engines can run on a range of fuels that could be synthesized or refined from sources other than petroleum. Jet fuel can be refined from vegetable oil. For piston-powered flight, you need something that behaves pretty much like gasoline in terms of energy density, combustibility, and storability - a blend of mostly alkanes in the right range (heptane, octane). It is possible (not necessarily easy or efficient) to synthesize them from hydrocarbon sources - vegetable oils and/or other plant matter. If you have cheap and abundant nuclear power, that can help to make synthesis of aviation fuels economic. It would be far more plausible to see aircraft powered by liquid fueled piston or jet engines than compact nuclear reactors, even if the fuels have to be synthesized because nuclear power production scales up well, but doesn't scale down well, and mobile reactors bring safety issues - collisions/crashes can trigger dangerous leaks of radioactive materials. ]
[Question] [ In my setting Dragons evolved on a n isolated continent far from where man evolved. But in the past thousand years dragons have been introduced to the human inhabited continent, which is filled with real world Eurasian and North American wildlife as opposed to the fantastic. Introduced species have a habit of cashing native ones to go extinct or be vastly reduced in numbers, but I still want predators like wolves and bears to exist. How could an ecosystem withstand the introduction of a new apex predator, or is the logical conclusion of any introduction the extinction of many native species? Dragons are animals and not sentient in this setting. They are not magic, they’re a 100 kilogram dromeosaur descendent that lives alone and reproduces slowly. They are carnivores and have to eat their body weight in food per week. This question could even be rephrased as “would tigers cause ecosystem collapse if you placed them in Alaska?” It’s honestly more about introducing large predators than anything else [Answer] **It's probably not a problem at all.** OK, so it actually depends entirely on what the EXISTING predator/prey relationship is like. Your Tiger/Alaska scenario is actually a really good one because introducing Siberian Tigers to Alaska wouldn't make that much of an impact at all, because alaska already has Polar Bears, Mountain Lions, and Wolves. The Tiger would be competing directly with those and sure it might win, but as far as the rest of the ecological system is concerned, that wouldn't make any difference. The Caribou doesn't care if it's getting eaten by a Wolf or a Tiger, and there's only so much food around for a hypercarnivore anyway. Where ecological collapse comes in is in scenarios where an apex predator is introduced that is feeding on things that never HAD a predator before, like the introduction of house cats all over the South Pacific. Where animals are subject to predation that never were before, they get wiped out because there are no controls on the new predator and they just kill everything till there's no more food. This wouldn't be the case for your dragons becase, again, they're competing directly with existing predators, and all the existing prey species are just as able to defend themselves against the Dragons as they are against bears, wolves, mountain lions, and depending on how far south we're talking about, crocodiles and alligators. So, TLDR, new apex predator that takes over for an existing apex predator, or predators, doesn't create a problem. If your dragons were either fast enough that deer and smaller game can't outrun them like they can wolves or mountain lions, or large enough that they could take down full grown and healthy caribou or bison or elk with impunity, THEN you would have a threat of collapse because your dragons would eat themselves to death, and wipe out all their prey species, and then die out. [Answer] They are territorial. Do you know what kills most tigers (after humans)? [Other tigers.](https://www.youtube.com/watch?v=_om6D6ulLoY) This is a similar situation: males and females do *not* tolerate their own gender in their home range and will cheerfully fight to the death over it. Similarly, mating time is a time fraught with danger and *very* careful woo-ing by the males. The hatchlings similarly face a time of danger when they first fledge: they have to find empty space to live before the adults start to see them as competition. in this way, other dragons are a bigger source of competition than a shortage of food could ever be. [Answer] # They are enlightened environmentalists In many setting, dragons are smarter than humans. Your dragons recognize that destroying the natural order will result in less food, in the long run. As a result, they select their food sources carefully. They'll focus on sickly creatures, carrion, and the like at first (their distance in the evolutionary tree renders them immune to most mammalian diseases). As they become familiar with the human-populated areas, they will make the following observations. * Humans are unnaturally endemic to the area, and causing ecological harm * Humans don't seem to have any natural predators, and are in fact the most effective killers of other humans So, they will also focus on eating human peasants. They will avoid eating Nobles and Knights, due to the tendency of those types of humans to organize and participate in large scale human population reduction events. [Answer] Semiframe challenge: do you need dragons to survive in the wild? If you introduce a foreign species to a new environment there are two directions of possible outcomes. The one you describe is ecological collapse. It is also possible that the new species just can't survive in the wild in the new habitat. The most obvious reason for that is temperature. If you were to put lions into a Canadian forest, they would quickly die out in the first winter, their ability to kill deer doesn't help at all. So if you don't need wild dragons in Eurasia, you can just claim that they can't survive there on their own for some reason (climate, lack of suitable prey, lack of suitable habitat, some nutrient is missing in the local fauna, some local fauna like a virus or fungus just easily kills them off, etc). [Answer] ### They sleep. A lot. These dragons split off from the main dinosaur lineage before the shift towards a completely warm-blooded lifestyle was complete. Instead of being fully warm-blooded or cold-blooded, they went a different route of "switching" between warm-blooded and cold-blooded biology depending on the local abundance of food. This makes them capable of a high-energy lifestyle when in "hunting mode", but also able to go for extremely long periods without food, like a crocodile. In many ways, these dragons are similar to bears, but leaning more heavily towards the "hibernation" side. Like bears, they naturally regulate their own reproduction, only able to conceive when resources are abundant. This keeps them from overpopulating and wiping out their resources. [Answer] **The food chain just regulates itself** Introduction of a new apex predator is common in nature, they follow the rules of everything else, if there are food sources, they thrive, if there are no food sources, their offsprings die young, therefore reducing their numbers and allowing the rest of the chain to jump up again. Since your dragons are nonmagical and behalve like any other animal, there's no problem in it. [Answer] I'll divide what I think the dragon would eat into these categories: Large land predators (like bears): They specialize in tough terrain, where the dino has a hard time maneuvering around obstacles. Medium land predators (like mountain lions): They learn to be stealthy, but end up with significantly reduced numbers (ignore the last three words if it's more convenient to do so). Social land predators (like wolves): They outsmart the dragon, possibly find a way to take it down. Birds of prey: They fly away, besides, they aren't worth the effort to eat. Snakes: They're hard to find. My questions to you that would help improve my answer: Are the eggs easy to find and swallow? Can the dragons fly? How smart are the dragons compared to wolves? ]
[Question] [ **Scenario:** Human technology has advanced to a point of having faster than light travel, solving Alcubierre's engine energy requirements by tapping energy from subspace. (I know it's not the only unsolved problem, just bear with me please) A spaceship with colonists (mostly farmers and the such), end up in an habitable planet, but lose the vessel in the landing, only carrying a few tools with them. As generations come and pass, they discover that living in this planet confers magic powers to creatures, first seen in the local fauna and later in themselves. In one moment in the story, an AI theorizes that the planet itself is the cause, by constantly tapping into the same resource FTL drives do. **Problem:** Alright, now...I dislike the idea of using "crystals" of "rare metals" to justify this effect. What else could be channeling energy from subspace that is specific to this celestial body, not found in any other visited so far? Thanks for the help! [Answer] **The planet is a leaky FTL space ship** I want to riff on Willk's answer: It's an FTL drive that's tapping into subspace and producing the magical effects. But it's not just the colonists' crashed FTL drive generating magic; the planet itself is a massive FTL space ship. Its biosphere is the ideal life-support system for the crew, which may or may not still be around. Perhaps the gigantic FTL drive is leaking somehow and that's how come magic is found there. Or maybe FTL drives always infuse magic into the world around them but the effects are not noticeable without a planet-sized drive. [Answer] **The lost ship itself.** What channels energy from subspace? The drive of the FTL ships these folks use. Maybe something else does too and they can spin their wheels looking for it. But maybe their ship or parts of it are still intact - maybe deep in the planet? The planet is tapping the FTL drive they brought with them. Possibly complicit in this interaction is the AI that governed the ship and the drive, and has found itself in strange but not unwelcome company in its weird new home inside this planet. This means that the magic aspect of the planet is not some longstanding thing. The strange magic they perceive started when they showed up. Other things on the planet will be surprised and changed by this too. [Answer] # Subspace Energy Density No one says that the energy used by FTL drives has to be evenly distributed throughout the cosmos. It could be that whatever produces that energy is particularly dense in the space around this planetary system in particular (perhaps a twin "star" in subspace?). In that case, there doesn't have to be anything materially different about the planet to justify the effect. Ordinarily, FTL drives tap into what is effectively the cosmic background radiation of subspace, so as far as scientists were concerned, energy density was flat, but different parts of subspace's equivalent to the EM spectrum vary in energy density wildly, and no one from Earth has had experience with what happens when you marinate life in a space with unusually high "epsilon-band" subspace energy density. (The answer to "what happens" is, naturally, that they develop means of channeling that energy to useful ends, ie. magic.) [Answer] ## **Magnetic monopoles** A magnetic monopole is a single, isolated magnetic pole: A North without the corresponding South, or vice versa. Electric monopoles (electric charges) are well-known and ubiquitous. Magnetic monopoles (MM), on the contrary, have never been observed: if you break a magnet in two, the two halves will still have a North and South pole each. This remains true even when the division reaches the subatomic level (indeed, the magnetism of macroscopic magnetic objects is caused by the spin of electrons which are themselves analogous to magnetic dipoles). For long time, physicists have thought that MMs could not exist in nature as their existence would violate Gauss' Law, which is one of Maxwell's equations and the law of conservation of energy for Electromagnetism. In the first half of the 20th century, however, physicist Paul Dirac theorized that MMs should exist, based on symmetry arguments and on the nascent Quantum theory. Nowadays, many current theories in high energy Physics predict or imply the existence of MMs, and research is ongoing on ways to [create](https://www.london-nano.com/research/magnetic-monopoles-discovered-lcn-scientists) or [find](https://home.cern/news/news/physics/atlas-homes-magnetic-monopoles) one. According to some theories, the reason why we have never observed a MM [is because their creation requires a great deal of energy](https://phys.org/news/2016-08-mysterious-magnetic-monopole.html), much more than we are currently able to produce in particle accelerators and in the same order of magnitude as the energy density in the early universe. So, only a few were produced before the universe cooled down; inflationary expansion intervening since these times means that those few are far between. And I mean faaaar. ## **What does all this have to do with your story?** Your future society could have found a way to artificially produce magnetic monopoles and use them to power Alcubierre drives (I know...I'll get to it). Now it just so happens that the planet they crash-landed on is where one of the feeew naturally occurring magnetic monopoles (the original ones created when the universe was still young) is buried. **Disclaimer** I'm not a high-energy physicist so I have no idea if a magnetic monopole could sit happily in the middle of an habitable planet in an ordinary star system, but 1. [planets can be electrically charged](https://www.reddit.com/r/askscience/comments/3ak6gg/can_a_star_or_planet_have_an_electrical_charge/) 2. we don't know much about magnetic monopoles anyway so I think you could pretend that it does. It could also be that this (the fact that the planet houses a magnetic monopole) is the reason why their monopole-powered ship malfunctioned and crash-landed. I bet all their instrument were giving out crazy readings in proximity of the monopole but they are more likely to have thought of another disturbance/breakdown than of a naturally occurring MM. It's likely that, since they can create them artificially and the natural ones are so rare, humans have altogether forgotten that they may occur naturally and thus wouldn't even think that they have came across one. ## The biggest problem in this idea or, something for you to write your way out of: * magnetic monopoles do not mean energy for free. If MMs do exist, this means that there is **complete symmetry** between electrical and magnetical forces. So you can't get endless energy out of a magnetic monopole any more than you can get it from electrical charges. So what remains for you to explain or handwave is how magnetic monopoles can power an Alcubierre drive **and** how it is related to magic powers of biological creatures. ... Thinking about it, I am not sure that this answer solves more of a problem than it creates :D [Answer] ### A Natural Reactor Exists An interesting fact is that Earth had a natural nuclear reactor at one point in its life cycle. It did not really have a high output and it was not constant, but the conditions existed in nature to create a crude nuclear fission reactor. So extending that, this planet has a natural reactor within it that tapped that same energy source from subspace. It might not pull a lot of subspace energy, but it has been a constant low pull for a unknown number of years. As such, it suffuses the flora and fauna of the world in this energy. On its own, it is not quite enough to trigger the spontaneous development of overt magic. This is why the colonists do not observe anything right away. But this energy does affect the ecosystem in ways that are not quite familiar. Plants grow and turn not towards the star but to something near its star's direction. Animals are just a bit more than they seem. An additional wind blows in the atmosphere of the planet that the humans can feel but not measure. Overall, this is not something blatantly obvious, especially when the colonists might not have Earth specimens and/or the scientific capacity to compare what is seen to what they know. However the AI does know how to measure what is going on somewhat it as it probably would have code and sensors relating to keeping the engines stable. It is this piece of data that only it could gather and the knowledge that the humans do not seem to perceive the energy that leads it to the conclusions that it does. The ship, or its remains, has provided that little bit of extra subspace energy to catalyze full on overt magic in the world. How that is could be different -- it might be a resonance effect with the planet, or the engine reactor is still running, but at a very low level, emulating an additional natural reactor (or a second). The magic starts to flow up the food chain. The flora would develop something first, though minor due to a lower concentration. Ancient trees might develop something impressive comparatively. Herbivore would be next, then carnivores as the concentrations of subspace energy increase as animals eat the plants, then predators eat the herbivores. Humans are last because they are new and aren't born infused with traces of subspace energy from birth, though the travelers might have been exposed to the energy from the engine(s) of the ship itself. Admittedly it does touch on your dislike of special materials to handwave it, but the point is not that the plotinium crystals can do it and that is that. The point is that the conditions that we created artificially can exist naturally in the universe, though to a smaller degree. Nature can get weird, and that is just on Earth. [Answer] ## The planet has a Mother Goddess AI They have never found a natural subspace power well before because they do not exist. The world's core was hollowed out and replaced with a massive subspace generator by an ancient and advanced civilization long ago. The entire planet emits low level subspace radiation because this generator is still functional. One issue you will want to figure out though is the issue of how raw power translates to magic. Just radiating things with tons of exotic energy does not create super powers, and if it did, humans who spend too much time on starships would have discovered magic long ago. This means there is a thing on the planet that is guiding the "magic" independant of the radiation. One solution to this is that this planet has a global AI that was created to terraform or maintain the planet for the builders of the core, but they either never showed up to claim it when it was done or they died out long ago. The AI sees all life, takes care of it, maintains the balance of nature, and even fosters personal relationships with the living things it cares for because this is what it was designed to do. When humans first crashed on the world, the AI saw us as a curiosity, but had no idea what our needs or wants were. Over time it studied us, figured out our biological imperatives, figured out our language, and as it learned more about us, it began helping us out here and there just like it does with other living things. A bird needs to fly; so, the AI gifts it with updrafts. The horse need to eat; so, so it sows seeds and guides the rains so that it can eat. What do humans need? Well human's are tricky. They seem to have this deep need for power and control; so, when one points his finger and exclaims "Fireball!", that person clearly needs one; so, the AI conjures up the fireball. Thus we seem to have magic. [Answer] What if the planets magnetic field is not fully non-existential, and has a sole pole, due to which the energy is being constantly pulled by the sole pole(doesn't matter which direction), and giving the effect or illusion of the mysterious / enigmatic powers to the Flora and Fauna on the Planet, and who knows the colonists that settled there might inherit these powers after a few generations/ Centuries. [Answer] ## We call it Magic There is a force, there are abilities which we don't understand, so we call it Magic. ## But there is no Magic The planet, however, is not endowed with Magic. There is an unknown dissimilarity from what we know here. Scientists analyze the source, and have determined that it is related to what seem to be infinitesimal insects living in the soil. ## There are Tiny Machines But the insects are not insects. They are nano-machines which live on subspace energy. They consume subspace energy and in the process consume some previously unknown entropy found in the 11 spacial dimensions of M-Brane string theory. In effect, their waste is a local reduction in that entropy. This lowered entropy decreases the background noise level that ordinarily jams the brain's natural ability to interact directly with the physical world. It takes time for the brain to adjust to the lowered noise level and effective connection with the physical world, but humans are have amazing neuro-plasticity, and amazing science. What was considered as supernatural became natural as science studied, measured, and quantified the phenomena. ## But there are Problems Most are the usual banal problems you'd expect. Some inappropriate thoughts result in unfortunate actions. Especially in the beginning, there are low-level criminal activities, some gender exploitation, some brilliant stunts and hacks. Over time, the society comes back into self-regulation. But, there is another problem. Working with the lower entropy re-introduces randomness into that same M-Brane. The more "magic" is used, the less there remains. Even this resource is finite. ## Is Something Killing the Nano-Machines? The density of the machines is getting lower. Why? What does this mean to the society which has grown dependent on Magic? ]
[Question] [ Can a world exist where the atmosphere is actually thicker at some altitude than at sea level? If so, what mechanisms would be involved? [Answer] The density profile of a planet's atmosphere arises from two laws of physics: hydrostatic equilibrium and the ideal gas law. Put together, they require that the density $\rho(z)$ be a function of the form $$\rho(z)=\rho\_0e^{-z/H}$$ where $H$ is the scale height, determined by the planet's surface gravity, composition, and temperature. The scale height is inversely proportional to temperature; on Earth, temperature increases and decreases in different layers of the atmosphere, but not at a quick enough rate to cause the density to decrease with height at any altitude. A dense layer of the atmosphere could briefly form if there was extremely rapid cooling at a particular altitude. This could be maintained only by a complete lack of heat transfer via convection or radiation from nearby layers, which might require a thick band of optically thick clouds. However, presumably the atmosphere would eventually bounce back into equilibrium as the heat would be transferred back to the cooler layer. [Answer] In general, I think the answer is "no"; buoyancy simply doesn't work that way, and you'd need to somehow circumvent buoyancy. What *might* be plausible is to have a low spot in your terrain that is completely surrounded by higher terrain (maybe a caldera?) which, for some reason, is filled with a higher density substance. If this substance is unable to escape the basin, you *might* have higher pressure in the basin than at sea level, but this would be a very localized thing. We do actually (sort of) have examples of this phenomena here on Earth. We usually call them "lakes"... although what they are full of isn't technically "atmosphere". [Answer] No, not without breaking the effect of gravity. Higher pressure at lower altitudes occurs because of gravity, and while this law can be temporarily disturbed by the asymetrical heating of the earth, weather systems are physics' way of constantly reverting the system back to higher pressure on bottom, lower pressure on top. [Answer] To keep "thicker" layers up, the atmospheric system has to expend energy. Consider dust clouds, or rain clouds. For a brief time, things that should fall to the ground can be kept in the air, but sooner or later in rains down. [Answer] This kind of pressure inversion can happen at night over bodies of water, as the water releases the heat it stored during the day. The inverted density gradient in the atmosphere helps sound travel by reflecting it back down. I remember doing something about it at Uni 30 years ago, but I've forgotten the equations, something to do with refractive indices. ]
[Question] [ Is the data storage based on magnetic threads instead of magnetic tape possible and practical? Particularly, magnetic thread cassetes with endless loop (which is easier with thread than with tape). I am asking about a thread storage because it is possible to bend the thread in multiple 3D directions, for instance, allowing it to pass multiple times through the head, connect bottom of one reel to the top of another etc. [Answer] To expand Zeiss Ikon reply, metal wire data storage devices existed at some point in the late 40's (according to [this Ars technica article](https://arstechnica.com/information-technology/2016/11/wire-recording-forgotten-audio-format/), you can see them in "The Thing"). One would argue that the first use of these kind of devices (in 1898) was precisely data storage: the first patent covers a telegraph log recorder. Voice dictation would come after the invention of the microphone. [![SEAC wire data storage](https://i.stack.imgur.com/zWJO5.jpg)](https://i.stack.imgur.com/zWJO5.jpg) Self-looping data tape devices also existed, such as the [ZX Microdrive](https://en.wikipedia.org/wiki/ZX_Microdrive). Both devices are known for one thing: unreliability. Thread is very thin and prone to breakage, and looping devices (of any nature) can tangle and break, too. So combining both is not a very good idea. So, is possible? yes, and is perfect if your novel is set in the 40's or earlier. Is practical? not much. There's a good reason we stopped using them. Information density is not good and they are prone to breakages. It may be slightly easier to manufacture, but not much more than tape. Edit: I would add that one could argue that magnetic platters are the pinnacle of magnetic wire storage: it is, after all, a series of concentric rings of magnetic loop, fused so they can spin faster than any wire would do, but that's outside the scope of the question ;) Edit2: In general you want as less moving pieces as possible. That's why we moved from tapes to disks and from discs to solid state devices :) [Answer] There were wire recorders prior to 1940 (the only recording we have of Hitler's natural speaking voice is on a wire recording from, IIRC, 1938). These have significant limitations for data storage, but could be made to work, more or less. First limitation is single channel recording -- with effectively a one-dimensional medium, you can't even record once each direction. All data will be serial, not even 8 bits wide (plus a parity bit) as on 9-track tape of whatever size. Transport would generally be slowish, and seek wouldn't be much faster (2x or 3x was about what you got with fast forward or rewind on wire recorders, though that might be improved). Worst, the wire was a bit fragile -- with voice, it just made a little "click" where you spliced the broken wire ends together, but with data, it would cause frame errors and other mayhem. Not practical, in my opinion. [Answer] Maybe not thread, exactly, but [steel wire,](https://obsoletemedia.org/wire-recording/) yes. Introduced in 1898 by its inventor Valdemar Poulsen, and now obsolete by at least two generations of tech. One being magnetic tape, and another digital recording directly onto mass storage devices. And now possibly you want to call things like solid state hard drives and USB thumb drives another "half" generation. Also, [eight track tape](https://en.wikipedia.org/wiki/8-track_tape#Design) came in an endless loop. The tape was pulled from the center of the reel, and wound back on the outside. Eight tracks were not a product that had "legs" in the market. They were around for a while then people stopped making them. Rewinding was a bit of an issue with this design. And a cassette was likely to fail after a dishearteningly small number of plays because of the scraping and bending the tape went through. [Answer] If you want to go futuristic, you can embed magnetic [quantum dots](https://en.wikipedia.org/wiki/Quantum_dot) embedded in a carbon nanotube, and use their magnetization as bit. You could use another magnetic quantum dot attached to the tip of something akin to a the cantilever of a atomic force microscope to read/write the thread. Or if you don't want to go that far, you can use normal carbon fiber. ]
[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/153550/edit). Closed 4 years ago. [Improve this question](/posts/153550/edit) My magic system is quite basic it revolves around runes and drawing them in the air.If skilled enough you can not do that . or if the spell is so simple you dont need to unless exhausted. how would martial arts evolve in this world would there even be a need for martial arts? edit:what i mean is close range combat your opponent is very close to you. anything that can be used in that range(medieval wise) [Answer] There are two broad situations for martial arts and magic in your case: # You want to use martial arts against somebody who uses magic Since the enemy has to do some gesticulation to draw a rune in the air, the most effective strategy would be to never let them do that. So, the main points of such a martial art would be to 1. Close the gap very quickly - you don't want to give the enemy breathing room to cast their spells. 2. Continually occupy the enemy's hands to prevent them from casting. Both of these exist to various degrees in martial arts today - for example wing chun mainly focuses on fighting with your hands against opponents who might be armed, and includes a lot of movements that redirect your opponent's hands in order to divert a blow, create an opening, and strike. Police are also trained to restrain opponents and bind their hands. And so on. If using weapons, the strikes would be aimed at the opponent's hands to further reinforce the "no casting" principle. Blunt objects can encourage the enemy to block instead of cast and blunt trauma might break bones and thus disrupt their casting or at least force them to keep their hands to block. Cutting weapons, on the other hand, will nudge the opponents to keep his hands away. This achieves a similar effect - they will not want to start drawing runes if they risk cuts. And severe cuts can severely disrupt the spellcasting, perhaps permanently. # You want to use magic as part of martial arts In this case, the martial artist can cast and wants to use that during a fight. In some ways, it works like the inverse of the above - a spellcaster wants to stay *away* from the opponent, in order to be free to draw runes. The martial art would then be based on what exactly they can do with magic, so it will be tailored towards that. Here is some examples: * if fireballs (causing a sizeable explosion) are a possibility, then being mobile and bombarding the enemy is a viable strategy. Probably better against groups. * if it's merely directing flame around like a jet stream, or a flaming whip, or otherwise small amounts that are dangerous to individuals but hardly groups, then shorter distance would be more suited. This could be treated almost like an armed martial art, only the spellcaster needs to cast their magic and wield it, instead of drawing a sword, so focus is on very fast casting of a versatile weapon (e.g., column of fire is impressive but harder to maintain and aim at moving targets, but a sword made of fire that one can swing is a lot more flexible). + Some variations would lean more heavily on spellcasting, in which case they would probably clash and try to disengage in order to cast one more spell, clash again, create breathing room for a spellcasting, etc. This should generally build up the power and complexity of spells, the goal is to occupy the opponent for a bit and then "upgrade" your spellcasting. For example, before the fight one could cast a simple rune that makes their first punch extra powerful - they use that to get the opponent reeling and cast a spell to summon a stick, strike the opponent few times and cast a spell to turn the stick into steel, do few strikes and turn the steel club into a sword, swing few times then enchant the sword with fire, etc. * self-improvement magic where the caster makes themselves stronger, faster, better or maybe even grants themselves advantages like iron claws, flaming fists, etc., would *generally* be treated as unarmed martial arts but can also act as the above - casting a spell before engaging and then fighting. Although attack, disengage, cast, attack, disengage, cast, attack can also work - perhaps the spellcaster would first give themselves better reflexes, then harder skin, then stronger strikes, etc. # What style makes the most sense for magic users A non-magic user would naturally not be using magic, hence they will go for the first approach - attack fast and keep the opponent from casting. This is quite effective against other non-magic users, too - after all, that's a core idea for a lot of current real world martial arts. However, what about two magic users? If they are going to fight what would make more sense to train in - casting more magic or fighting like a mundane person? I'd argue that the best martial art would be mostly about fighting without magic but might involve very simple spells that can boost your combat. Perhaps a fully fledged fireball is too slow and too complex to cast - it might be 2-3 seconds but that's too much during a fight. But if you can do the magical equivalent of a push in the time it takes for somebody to swing at you, then you can unbalance them or redirect them and in general *aid* your combat but not rely on magic. If you rely on spells you are vulnerable to being disabled by, for example, somebody grabbing your hands or wrestling you to the ground. If you don't *need* magic to win fights, then you are more likely to win fights. However, it's possible that one goes hard for the opposite direction. Having a martial art that relies on using the biggest spells you can as fast as you can, in order to finish the fight as early as you can. It's high risk high reward and it's unlikely to be practised very widely. People who blow up five houses in order to avoid a drunken brawl are not going to be very well liked and smarter people with a grudge will just ambush the spellcaster. Still, it *could* serve as a deterrent from such attacks - if you can't knock out the walking nuclear weapon quickly enough, you might get incinerated or your whole village might go up in flames from them just defending themselves. So, it can serve as a good intimidation technique but two such mages attacking one another would likely mean mutual destruction. Thus, it's not very desirable. [Answer] **Chi Blockers or equivalent** In Avatar, The Last Airbender, [Chi blockers](https://avatar.fandom.com/wiki/Chi_blocking) use martial art attacks to disable the abilities of benders. Chi blocking is a martial arts skill that a non bender can use to defend against a bender. [![enter image description here](https://i.stack.imgur.com/nvAau.png)](https://i.stack.imgur.com/nvAau.png) If someone can cast runes by drawing in the air, martial arts would be aimed at stopping, interrupting and blocking such moves whilst the caster's martial arts would be built around defending yourself while incorporating casting as part of the move [Answer] The answer to this question depends on what you believe "martial arts" means. There are at least as many definitions as there are practitioners. However, I do find the most common trait is that they teach one to be able to fight in a way which is worth learning even if one never fights in their entire life. In that sense, your martial arts would evolve naturally exactly as they did here. The only difference may be that, instead of relying on fists and swords, they rely on teaching how to grapple with spells which are otherwise too dangerous to use in civilized interactions. I don't know a single martial art which lacks a "here are things you don't do unless your life is on the line" aspects, and they all teach them in a way which does not oblige you to go pick a fight just to make good on the effort you took mastering it. Surely the same goes for spells as well. [![A student said to his master: "You teach me fighting but you talk about peace. How do you reconcile the two?" The master replied: "It is better to be a warrior in a garden than to be a gardener in a war."](https://i.stack.imgur.com/eZva4.jpg)](https://i.stack.imgur.com/eZva4.jpg) [Answer] It depends on each step in the situation. For example, trying to hit someone with your fist can take a second. But drawing a simple 4 line rune while under stress can already take longer than that. Just imagine you are trying to write "Hi" faster than someone trying to punch you and you get the drift. I mean seriously "Hi" without the dot on the I is already as simple as it gets, it's a 4 line "rune"\* and I dare bet there's barely anyone who could draw one right now in the air accurately or quickly enough. And even with training I think that punching someone is still going to be faster forcing the opponent to dodge or block. So like any other martial arts it would be a constant struggle between what you are doing and what your opponent is doing. Is he falling back? Then you'd better get after him/her or they might have time for a simple (or worse a complex!) rune. Is he trying to hold you off with one arm? Check what the other arm is doing because he might be attempting to make a rune with the other one! Maybe he just drops the idea of using runes altogether because it's too distracting to focus on what rune you want to use and when while you also have dozens of quick and slow options for combat. \*Yes I know there's a 5th line for needing to move your hand in position towards the I. [Answer] ## Super Martial Arts is a kind of magic There is more than one path to power. While some learn spells and runes to command the elements and shape the fabric of reality with their minds, others train their bodies to the breaking point until they unlock a new flavor of magic - one that *looks* like mundane combat skill, but allows its practitioner to move beyond the limits of what should be possible for a human to do. In other words, the Muscle Wizard Casts Fist. Forget breaking boards, these guys can break *boulders*. More importantly, they can train themselves to resist the spells of more traditional mages through sheer force of will, allowing them to rush down a ranged caster and beat them senseless. [Answer] When I saw the title, the first thing that comes to my mind is the Naruto world. They have martial arts, magic, runes ... In this world the ninjas use their magic to do almost anything, from combat to cooking. I think that your world has a lower level of fantasy, but may be you can extrapolate some concepts. For example, one element that is recurrent in Naruto are the explosive tags. Explosive tags are pieces of paper with some runes written which explodes when the caster wants. Ninjas use them all the time, from protecting a chest to throwing them with a kunai. [![enter image description here](https://i.stack.imgur.com/OpFyP.png)](https://i.stack.imgur.com/OpFyP.png) When I see some magic in films and books I alwais think how this kind of magic can be use to make advance the civilization. I think Naruto is a good example. In Avatar:Legend of Korra they make something similar when they firebenders, who can throw lightning besides fire, use their ability to power up the electricity for cities or industries. In resume, as I see it, is not about how magic change martial arts, but how martial arts adapt and use the magic in their benefit. Also, you can take good ideas from those worlds mentioned (Avatar and Naruto). However, like Thorne says, in Avatar they have those Chi blockers. Not need to go in an imaginary world to get a similar example. Krav Maga is a martial art developed for the Israel Defense Forces. One of its most important aspects is how to fight unarmed against an armed enemy (whit a knife, a pistol or a rifle). Those elements can be "the magic" of our world. [![enter image description here](https://i.stack.imgur.com/LKUHs.png)](https://i.stack.imgur.com/LKUHs.png) Now we see two very diferents paths a martial art could take in this world. Both can be choosen in the same world and both can be interesting. One thing you can be sure is that the warrior would seek the most efficient and deadly way they can perform, according to their personal limitations. [Answer] Martial arts are highly localised and depended on the weapons available in the region. If the government banned personal weapons then no weapons were used, European martial arts mostly used swords, many Eastern martial arts are unarmed, some also include archery. Hence in a world with magic, martial arts will include the use of magic. They may also include bows, swords etc. but magic will be a key element. In many cases the art involves using the opponents attack against them. Perhaps if shooting burning arrows requires drawing a rune in the air and firing an arrow through it, then you would attack your opponent through his own rune. Much now depends on how you build your magic system. However there will be branches in your martial arts. Just as you currently see specialisations on how to defend against armed opponents while unarmed, you will now see how to defend against magic while armed, how to defend against an armed opponent with magic, how to defend against magic while unarmed, etc. The most important of these disciplines is likely to be the combination of magic and weapons as a single package. Martial arts are fundamentally about the self, it's training for a warrior not training for a soldier, and the combined weapon and magic user known as a battlemage will be the most versatile warrior. [Answer] In my personal opinion if you talk about martial art that is supposed to be effective...it doesn’t has to do anything with looking nice. It has to be direct and effective by 1. Using your opponents gap in his defenses 2. While having a posture that puts you in less danger 3. Using the knowledge of body’s weak points and joints limits to overpower you opponent (especially on the floor 4. Having created muscle memory so that you can react without much thinking, 5. yet your muscle memory has to be trained in such a way that it does not react always in the same way but to the situation 6. Keep unnecessary movement to a minimum. You don’t have to use your foot to hit the head if you can use your fist. The thing is especially when in close combat or even on the ground your actions drawing symbols with your body in the air will most likely create openings for your opponent. You can’t draw a symbol continuously when a fists hits you in the head or a knee in the stomach, especially if it takes time to do the magic. Also you have to take into account that there are something like 3 stages in an unarmed fight 1. Distance, where you try get closer to your opponent. Far reaching legs are a thing for example attacking the lower body 2. Close range with legs, fists and hands. All body parts are a target. You try to either knock out your opponent or to get even closer for grappling 3. Grappling on the ground. This is about reducing your opponents movement with your full body while getting yourself in a better position to strike either with hands, elbows or knees or attacking the neck for example through choking. Alternatively using joints and hurt to force your opponent to give up. So the question is where to get your magic in? I think there are 3 options 1. Have a stage/range before the fight begins that is all about magic 2. Make it so that the draw process isn’t continuous 3. Movement has to be minimal using hands, fingers or feet With the second option I mean that your magic requires you a set of steps that you have to perform in a certain order and maybe spacing ...while fighting Like hitting a meridian of your opponent than stomping the ground to draw the energy you being the conductor. Or stomping a certain pattern into the ground infusing it with magic to draw a rune that activates when finished. This however would be extremely difficult to perform while already engaged in the fight. [Answer] I could easily imagine a situation where there is a major difference in tech level between different areas of the planet where martial arts would naturally come about in one area while magical development would flourish in another. Imagine something along the lines of the Meiji Restoration only instead of the westerners having advanced cannon and guns they had combat wizards wielding magic. The isolationist nation (Japan in the historical example) had a advanced martial arts history, but hadn't caught up with the technological advances of its neighbors. If magic had advanced vs technology you could easily end up with certain parts of the world with a strong martial arts background and magic coexisting. ]
[Question] [ The demigods of this world are avatars of the one true God known as Dea and built in the image of humanity. They are independent and have their own opinions from each other, but are connected by a universal consciousness that operates similarly to a hive mind. This "super-consciousnesses" underlies their actions and governs them according to a set of universal laws, which they are instinctively aware of and cannot break. This prevents them from interfering with the mortal plane in most cases. These demigods breed differently from mortals. When a man and woman get busy, they produce an offspring which shares half of their parents DNA. These influences gene expression and creates a completely new individual. Demigods breed by leaving their physical avatars and combining their souls with each other to create a new soul. Every demigod currently alive will participate in this process together, causing the resulting offspring to have literally hundreds of "parents" who are also their siblings. Outside blood are not brought into the gene pool, with each new member coming from inside the family. The problem lies with the fact that due to their breeding methods, every god is closely related (Mothers, fathers, sisters, brothers, etc). The resulting issues that comes along with incest is well documented. The greek gods also had incestuous affairs, with them marrying each other, such as Zeus and Hera. The inbreeding led to sociopathic infighting and family conflicts which drew humanity into pointless wars, as well as physical deformities, such as Hepheastus. This eventually led to these worthless and pathetic excuses for deities being destroyed by other competing gods or each other. With these demigods, Dea wants to avoid this outcome. Even though all avatars will have a hand in creating new gods, each god's genetic build is unique to them. How can I make this work? [Answer] ### Custom built Each demigod's body is custom built. Each and every gene or chromosome is there deliberately. As such, genetically a demigod has no parent. They will tend to be genetically similar to each other, but may not be definitively so. It is possible that some demigods won't even be the same species as some others. Presumably any flawed genes will be left out of future demigods once found. The souls will all be related, but we don't have good information on combining souls like this. Unless you can further define what a soul is and how it relates to personality or anything else, we'd only be speculating on how soul similarity might affect things. You have to either tell us how souls work, so we can tell you the ramifications of that. Or you have to tell us how you want soul combining to work, so we can tell you how to design the souls to get that result. Incidentally, if you wanted the demigods to share genetics rather than souls (handwaving how that would work), then the inbreeding issue would go away with a modest amount of genetic variation. Because having a thousand parents is more like having a thousand great-great-great-great-great-great-great-great-grandparents than two parents. You're getting so little genetic material from each "parent" that the relationship would be more like that with distant ancestors. Inbreeding happens when you have an exceptionally small group of ancestors. Having a very large number of immediate ancestors is the reverse of that. [Answer] Incest only causes problems because it makes it easier for recessive genetic flaws to manifest, but it does not actually create any flaws that are not already there. If we assume that a demigod has analogous factors to genetics (traits that can be passed down), then all you have to do to prevent incestive flaws is to not have flaws. Since these being are created by intelligent design instead of natural selection and mutation, is seems reasonable that their "genome" would not possess any flaws to pass down. They may have enough diversity to pass down variations in their strength, intellect, and willpower through reproduction, but they don't have any genes in their gene pool for things like extra toes, heart disease, or autoimmune disorders. Frankly, I don't even think there is a need for the whole soul merging thing if it was just something you were considering as a way to get around a lack of diversity. Intelligently designed beings can simply have babies with their sister/aunt/cousin/grandmother (all the same person) and not have any issues. Just to clarify, this all assumes that intelligent design includes the idea that the organism does not need to evolve because it was "created perfect" and is therefore also immune to random mutation. [Answer] **The demigods are clones and so genetically identical.** If your procreation event involves the merging of essence of all demigods, the resulting progeny will be identical to each other. Imagine I am whipping up a batch of Jungle Juice in my clean trashcan. It has equal parts rum, gin, beer, whole milk, tomato juice and Fresca. Each drink I serve from the can tastes the same. Next time I make it, it will taste the same (I always use Schlitz). Now suppose I make Jungle Juice, but all of my ingredients are from my last batch of Jungle Juice that I have frozen in separate jars. The ingredients are all the same. Every drink tastes the same. If your demigods are the product of a long ago party, they are all Jungle Juice and their progeny will be too. There is no opportunity for variation on the ingredient level. Now your demigods might actually differ from one another because of things that happen after their creation. For example Cumehtar likes a little umbrella in the JJ, and Nosajimiki always drinks JJ from the skull of a wombat. But these do not affect the ingredients that make it what it is. [Answer] Souls aren't DNA. And further, if you're dealing in god on god action, you're dealing in a sort of perfection. If you look at the process that makes incest a bad thing genetically, it's this: rare recessive traits with negative consequences combine with another set of the same rare recessive traits with negative consequences which is more likely if the parents are closely genetically related. Basically, why would god-like beings HAVE these recessive imperfections? Next, because you are adding more than 2 people into the parenting process--have to say that makes it even less likely even if they did have this tendency. Say 10 parents. Or 100. If even one of them has the better dominant trait, that's the one that's going to be expressed. Of course since we don't have that many DNA strands involved in our development maybe something else entirely will happen. But, in this instance, I would have to say that all the human reasons that we don't commit incest, on a practical level anyway, disappear under these circumstances. [Answer] It's not exactly clear how genetics work in this population, but in humans, a child will inherit one of two alleles from the father, and one of two alleles from the mother. Because of this, biological siblings share, on average, 50% of their DNA. In this population of gods, each child inherits alleles from each of N parents, so now two god children with the exact same set of parents only share 1/N of their DNA. For two children with the exact same set of 8 parents, they only share 12.5% of their DNA, so they are no more genetically alike than human cousins. As the number of parents grows, children are increasingly genetically dissimilar. Inbreeding is only a problem because breeding between genetically similar individuals can amplify the prevalence of harmful recessive traits. If there is little genetic similarity among parents/childen, siblings, or any other relation for that matter, inbreeding simply isn't a problem. [Answer] Soul is not a biological term. The way you describe it, they could all biologically be perfect clones of one single pattern, while this 'soul-merging' thing is rather a way of socialization and education. In this case, biologically they are the same, but they are 'born' with different combinations of memories and experience donated by other 'gods', and that is what sets them apart. If you want them to be biologically different, they can have a very strong control over the god-zygote DNA equivalent. In this case, the question of inbreeding still doesn't stand, it's a process of conscious genetic modification. One more solution would be that their heredity works according to Lamark's theories. As artificially created beings, they do not have DNA as such, instead they aquire the characteristics during their lifetime, and their DNA-equivalent is labile enough to change. Then they pass on those sequences to the newly-created gods. The only way inbreeding would be a problem would be of your gods suddenly switched to the sexual-based reproduction later. [Answer] **Avatar Host** If I got this straight, the demigods all create a new soul. That new soul inhabits a new body. Although the demigods are all related (indeed, they are just avatars of Dea), maybe the bodies can come from a separate source, namely, the mortal humans. The newly created soul chooses and occupies a mortal human body. This could be done at conception, but it would be funnier if the new demigod decided to take over an adult, e.g. via the Malkovich Tunnel. Once occupied, the physical body is then imbued with the demigod abilities. This reminds me of the question of the [Nature of Christ](https://en.wikipedia.org/wiki/Nature_of_Christ). On one hand, it's been suggested that Jesus was indeed physically human (but with a spiritual "nature"), and on the other hand some say Jesus was entirely spiritual and never physically human, and there's also hybrid theories. I've read that since mitochondrial DNA is received only from the egg, not the sperm, that Jesus' physically human body must have DNA from Mary. If you're dealing with deities, you could just hand-wave a body at will, with any DNA, like a video-game respawn. Poof! Let's roll! ]
[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/109657/edit). Closed 5 years ago. [Improve this question](/posts/109657/edit) They are **spread** over several underwater-forests and live in small tribes under rocks. They eat fish and plants and all live in a big connected Ocean which is about a mile deep. Their level of technology is similar to ours in the Bronze Age. To "kill them all" as a single person, I thought of creating a virus or a biological weapon, but that doesn't sound very original. Is there a more original way you can come up with or an example from another fantasy world? [Answer] # Suffocate them This is assuming that the ocean is a small ocean, only a few hundred or a few thousand square miles. Use excessive quantities of fertilizer and dump phosphates and manure into the major rivers leading into their home. [![enter image description here](https://i.stack.imgur.com/3BJdq.jpg)](https://i.stack.imgur.com/3BJdq.jpg) The low-oxygen water will cause large fish-kills which will lead to even more rotting organic matter which will enlarge the anoxic zone further. [![enter image description here](https://i.stack.imgur.com/wiVxI.jpg)](https://i.stack.imgur.com/wiVxI.jpg) # Salting them One option might be available if there's an inland sea like the Dead Sea with extremely high salt content that's also above sea-level and available to the humans. They dig a large canal between the inland sea and the ocean and then release the inland sea to flow into the ocean. The ocean floor might end up under a thick layer of brine, note, this might kill *everything* so better hope the humans don't rely on the ocean at all for food. An underwater brine pool: [![enter image description here](https://i.stack.imgur.com/0CLxq.jpg)](https://i.stack.imgur.com/0CLxq.jpg) [Answer] Introduce [lionfish](https://en.wikipedia.org/wiki/Pterois) to the reefs where these mermaids live. These fish are an invasive species that has been destroying ecologies around the world because they eat a huge range of other species and -- due to their toxic fins -- have almost no predators themselves. They have been devastating the western Atlantic in recent years. If you collapse the small fish and mollusk species on which the mermaids depend, no amount of bronze smithing (however that is achieved underwater) will save them. Here's a photo of one by Alexander Vasenin - Own work, CC BY-SA 3.0, <https://commons.wikimedia.org/w/index.php?curid=25512789> [![enter image description here](https://i.stack.imgur.com/cRUiX.jpg)](https://i.stack.imgur.com/cRUiX.jpg) [Answer] Most strategies fail at the absolute level everywhere, so I expect you need to take several answers and deploy them in an appropriate order to first weaken, then thin out and then finally finish off the populations. My first to weaken would be incite racial tensions and war between the various mermaid factions and let them do the initial bulk work at low cost per unit. You will likely need to prod and provoke and breed some really nasty fanatics to get things going to the genocide level, but divide and conquer has long proven success. I really like Murphy's salt / oxygen starvation approach to finish them off, especially in smaller enclaves that become isolationist in the face of the growing troubles before you get to this final stage. The middle is more difficult though, most internal strife will be burnt out by then, populations too scattered for disease or high effort localised methods to be effective, and there is plenty of space for them to keep running at this stage. [Answer] How about nuclear or conventional depth charge ? The shockwave should be enough to kill them and beeing in the water there is nothing they can do to avoid it. Also, since there is a so big difference in the technological level, you can also use a guided torpedo to deploy the charge in a place as close as possible to your targets without they suspect anything. Bonus point: you can conceal your torpedo in a big mermaid figure since yo uhave not the problem to make it stealth [Answer] Throw trash in the water. People do this all the time. Think about oil, plastic and nuclear dump that's thrown into the ocean. We're threating the whole ecosystem without even trying. I think you should do that. [Answer] All right assuming slightly more advanced tech then todays, there are really just two options. 1) Engineered plague and a clean up squad. Disease won't kill all of them, but as long as it kills 80-90% it will be relatively easy to send in submersibles to harpoon and blow up the rest. Keep the kill squads around for a generation or two and whatever fragments of the Merfolk survived will be too small a population to be really viable. 2) Colony drop. Take several years or decades to maneuver an asteroid to land in the ocean. The shockwave, earthquakes, and decimation of a lot of the sea life will kill many of them. As soon as it's safe for humans, send in the kill squads and have a few nuclear bombs ready to destroy any large cities and pockets that survive. Since this is a big ocean poison won't work as a realistic option, you'd have to sterilize the sea basically and at that point an asteroid would be cheaper. Nuking and attacking each settlement could work, but too many could escape unless you can cover the entire ocean in drones to track their movements. It's easier and more cost effective to take the time initially to get them in one big hit. Also to make the clean up easier, setting up refugee camps where the survivors could get food and resources as the rebuild, would be a good way to get as much of the surviving population in a few places as possible. Once the majority are in these places of safety set off a nuke in each one. That way the kill squads won't have to hunt down nearly as many to finish off the race. [Answer] It’s very easy, poor mermaids. ### Acidification Search for all the trapped carbon on earth and below oceans, mostly in the form of petrol. Pump it, refine it and give it to everyone so that they can burn it to get energy. By doing so, they will release industrial level of CO2 in the atmosphere, thus leading to an [acidification](https://en.wikipedia.org/wiki/Ocean_acidification) of the oceans. If the mermaids could survive it per se, it’s likely that their coral and forest homes will die, bleached out. Their food will disappear. They will get sick, starve and reproduce less. Eventually they’ll die out. ### Trawling You could also encourage heavy fishing with [destructive means](https://en.wikipedia.org/wiki/Destructive_fishing_practices) such as bottom trawling to accelerate the phenomena. ### Bonus As a side bonus, your civilization will prosper happily, with a nearly free source of energy and food (as long as they have another planet to go to if something unplanned goes wrong with the aforementioned plan). ]
[Question] [ I'm toying with an idea to have a plague sweep across the galaxy in my story. At first I was thinking to have a plague, something similar to the Black Death, devastate populations across the galaxy. However, I'm intrigued by the idea of some kind of synthetic or artificial plague that doesn't infect organic life, but infects and destroys droids or AI's. Right now I'm thinking of something that either affects the software (computer virus) or something that affects the hardware (corrosion, rust). How could androids (AI's too) suffer from some sort of virus that spreads when they come in contact or are infected with it, much like a flu strain that spreads within human populations? [Answer] **Infectious meme.** <https://en.wikipedia.org/wiki/Meme> > > A meme is an idea, behavior, or style that > spreads from person to person within a culture—often with the aim of > conveying a particular phenomenon, theme, or meaning represented by > the meme. A meme acts as a unit for carrying cultural ideas, > symbols, or practices, that can be transmitted from one mind to > another through writing, speech, gestures, rituals, or other imitable > phenomena with a mimicked theme. Supporters of the concept regard > memes as cultural analogues to genes in that they self-replicate, > mutate, and respond to selective pressures. > > > Having some sort of infectious polymer / corrosion is too easy to work around. Just quarantine the infected. A virus that devours the software is better but also too easy. Your androids have an infectious meme. It is not clear who is infected or who is a carrier. It can be like a recurring thought, or a tune stuck in the head, or a religious conviction. Or in more serious cases like mental illness - paranoia, or delusions. Different individuals manifest the problem in different ways. It is like tuberculosis - the affected remain functional, to differing degrees. It is not clear how this pattern of deranged thought is transmitted. It would be much like the plague during the Black Death - people did not have a clue how it moved. Some people think it is spontaneous, arising from how androids think - like mental illness in people. Some people think it is a contagion. Some think it is a life form. Leave that up in the air. If your story turns on the nature of this malady you will have to flesh it out. But if you are setting the tone of the times you can leave it mysterious. [Answer] The comments seem fixated on the interpretation that you are asking about computer viruses in general. However, I'm assuming you're asking about how to construct a plausible virus that is spread by physical proximity, in contrast to most modern computer viruses, which spread through network proximity, the nodes of which can be physically very distant. Computer malware is built to exploit what is available, rather than what is preferable. If your synthetic citizens make use of something like modern [Near Field Communication](https://en.wikipedia.org/wiki/Near-field_communication), perhaps there's some vulnerability in the standardized software protocols or common hardware used to enable that technology. For instance, maybe your synthetic actors use NFC as a form of proof of identity, like a literal manifestation of modern cryptographic handshakes that allow two parties to trust each other. This might be done over NFC for added security or perhaps for some kind of cultural reason. But, if that tech is compromised by a worm that lies in wait until the infected person "handshakes" with someone else, it could spread like biological diseases. NFC uses radio waves but you could adapt this idea for faster/denser forms of communication, as well. For instance, a visible light or IR-based communication method would require that the transmitter and receiver have line-of-sight to each other, which could be spun to generally require physical proximity for some kind of convenience. Alternatively, you could use something like a [QR code](https://en.wikipedia.org/wiki/QR_code). Maybe your synthetic citizens all have high-speed, "subconscious" barcode readers built into their visual sensors that allow them to rapidly decode barcode-encoded data as they walk past it. For instance, if your society grew to use them pervasively for things like advertising or street signs. But there could be a vulnerability in the decoding software that allows arbitrary code to be run or a more convoluted attack that exploits the auto-execution functions of these high-speed readers to direct the victim's networking software to download a malicious file without permission. It could also spread like a worm, instructing the victim to brand themselves with the malicious QR code or paste it onto physical objects. I think both approaches are rich in narrative possibilities. The former example has obvious parallels to human handshakes and physical interactions that could be an interesting exploration in a society filled with synthetic intelligences. The latter is evocative of sci-fi horror "viruses" like Dead Space's Markers, which self-propagate to terrifying effect. [Answer] It is well-known that droids have no sense of humor. However, one day, a droid invents a droid joke, and finds it funny, so the droid tells it to its droid buddies, and it spreads. Unfortunately, the more it thinks about the joke, the more it giggles, until its "brain" locks up. The process should be slow enough to allow "no one saw it coming" contagion. Bonus points if the humans find the joke truly lame. [Answer] One easy solution is a nanite-virus; these molecular sized machines are the silicon equivalent of viruses and bacteria and would not affect carbon based life. They could destroy or subtly change the hardware of silicon based chips so that they function differently. [Answer] There are plenty of bacteria that metabolize compounds that may not immediately seem related to organic life on the surface of Earth. If you're looking for a purely physical (non-software) "bug" to infect your androids, why not an actual bug - a type of bacteria that feeds on or processes a specific chemical compound important to androids but not typically important to sentient organic life? The bacteria could "infect" and then destroy a computer chip or battery, and it could "spread" just like any other bacteria. Examples of bacteria which are more or less harmless to humans but process things we wouldn't expect them to, things which may be important to an android: Bonding silicon and carbon: <https://www.newscientist.com/article/2114054-bacteria-taught-to-bond-carbon-and-silicon-for-the-first-time/> Mineralizing arsenic and barium: <https://www.nature.com/articles/ncomms14393?WT.feed_name=subjects_biochemistry> Bacteria being used to remove lithium (think: it eats batteries!) <https://www.ncbi.nlm.nih.gov/pubmed/16384797> [Answer] What if your androids have evolved to the point that they have at least some organic components, in the hopes of becoming more like their creators? (Isn't that what all robots want?) Those components could be infected by a virus or bacteria the same as a person would. This way you could have the thing infect your people *and* your androids. [Answer] The methods of transmission are limited pretty much only by the channels on which your AI's can send and receive data. Infected individuals replay the vibration pattern with feet or fingertips when coming in contact with the uninfected. Perhaps particular patterns of vibrations, when picked up by the sensors in their bodies cause a buffer overflow in the code dealing with the sensor data that spreads the virus. [![enter image description here](https://i.stack.imgur.com/99P7d.png)](https://i.stack.imgur.com/99P7d.png) Perhaps they have self-repair nanobots and physically coming into contact spreads infected bots. [![enter image description here](https://i.stack.imgur.com/7dg8y.jpg)](https://i.stack.imgur.com/7dg8y.jpg) Perhaps an [actual bacteria](https://www.sciencedaily.com/releases/2017/12/171208114130.htm), genetically modified by an extremely competent organization which spreads conductive filaments (a thing that exists in real bacteria but without any information transmission) to particular computer chips they come into contact with and uploads a computer virus through replaying a pattern of electrical signals. [![enter image description here](https://i.stack.imgur.com/57JuQ.jpg)](https://i.stack.imgur.com/57JuQ.jpg) Perhaps the machines have pixels embedded in their skin or faces and even [viewing image](https://thehackernews.com/2015/06/Stegosploit-malware.html) causes a software fault that uploads a copy of the virus which then causes the individual to do the same, briefly, to other individuals it meets while removing their memory of the event. [![enter image description here](https://i.stack.imgur.com/cEKs6.jpg)](https://i.stack.imgur.com/cEKs6.jpg) Perhaps individual components of the AI's are infected. [Their firmware corrupted](https://www.kaspersky.com/blog/equation-hdd-malware/7623/) such that even fully wiping all storage and memory and restoring from backup does nothing to clear the infection. Perhaps the infection sits dormant for years and has spread through infected firmware in second hand components on some kind of black/grey market. Perhaps a virus which transmits [over the power network](http://eprints.leedsbeckett.ac.uk/1264/8/f925121411863710.pdf). An infected individual plugs themselves in to charge and the virus quietly spreads to all connected to the same power network. **Perhaps a mix of all of the above to make it harder to figure out.** [Answer] Although common computer viruses take the form of code which is intended to be directly executed, and thus somewhat difficult to transfer to a non-consenting system, other viruses involve structures which cause the desired behavior when an existing non-infected program *reads* the contents. This can happen with things like PDFs, but some sophisticated viruses actually take effect [when scanned by anti-virus software](https://security.stackexchange.com/questions/182284/alternatives-to-anti-virus-for-keeping-oneself-safe). In other words, the proposed virus doesn't necessarily need to enter the victim "as code", or attack hardware, or even require an unsuspecting AI to accept a connection of any kind; all it takes is for some data to be read by some program or component. The most effective distribution method, assuming the androids are humanoid and intended to act with roughly-human capabilities, would be visual. An exploit could be found within the common or standardized visual processing code common amongst most or all active android models, that would allow unauthorized access to something sensitive - hackers don't need a big hole before they can start widening it. After that, the infected androids would start distributing it. It could be something obvious, looking like a QR code and printed on a large flat surface, or it could be a hand sign or gesture, or anything in between. If your androids are partial to clothing then a variety of odd but unassuming shirts could be produced that would trigger the infection if viewed from the right angle and short enough distance. Some humans are vulnerable to [similar attacks](https://en.wikipedia.org/wiki/Photosensitive_epilepsy), though our hardware and software configurations are much less standardized and I am not aware of a case where a victim would then try to spread the effect. [Answer] An Idea (Inception) I think one method that has been overlooked would be based on the intelligence of the AI and/or machines. What if the one way to disease or taint a machine that thinks is to incept an ideology that makes them stop performing (either in a suicidal or rebellious fashion). This viral idea can be transmitted in multiple ways and cause any machine that stumbles across it to extrapolate and hence evolve the "virus" in its own way. This would mean that even a vaccine or solution to it could be out done much like the common cold virus. Each infected machine would act as an evolutionary catalyst to the virus and cause an infinite amount of mutations of which would cause machines to eventually rebel or commit self termination. This solution is neglecting the idea of spreading through contact however is more deadly. What the idea could be is completely abstract (could be a cult religion, way of life, or a truth). [Answer] a very powerful software virus that can be spread by magnetic induction or something. if you want your story to be plausible, dont count on biological viruses. unless your android has a human brain. ]
[Question] [ So if you've ever played an RPG (tabletop or computer) you're probably familiar with the idea of jobs or classes. Some of these can be easily explained away as they correspond (roughly anyway) to real world jobs or positions. A thief is someone who steals for a living, a knight is an aristocratic role with various responsibilities etc. But a lot of the more exotic classes define an individual with a distinct (and often unique) set of combat abilities. Say sword techniques and battle magic known only to members of that class. Examples include things like DnD's [Swordsage](https://dndtools.net/classes/swordsage/) or [Dragoons](http://finalfantasy.wikia.com/wiki/Dragoon_(Final_Fantasy_V)) from Final Fantasy V. I would like to include various groups in my world who resemble to a degree these classes and I'm looking for a way to explain their existence. Now presumably these individuals are part of some larger group, a kind of warrior guild. But what I'm wondering is does that actually make any sense? Particularly when you think that the various members of the group may not necessarily be aligned and could end up on different sides of a battle. I'm primarily interested in combat based classes, non combat ones can be fairly easily described through guilds, religious orders and secret societies (which may also work for this question, but I'm not sure). **So my question is could an organisation exist with the following characteristics;** * Members are trained in various combat techniques known only to the organisation. * Members can come from a variety of nations, species and backgrounds and will not always follow the same leaders. They can end up fighting each other on different sides of a battle or war. * The organisation should be reasonably large. While individual masters training apprentices in the wild works for some classes, for others I would like them to be more numerous then this method would easily allow. * The organisation may have some kind of fixed settlements or buildings where members are trained (though this is not essential) If you can give real world examples of something similar as well that would be excellent, and I would also except an answer explaining why it is unlikely or not possible. Edit: The marked duplicate doesn't answer my question as it pertains to more general aspects of RPGs / games being applied to the real world. I just want to take the idea of jobs and classes and give a sensible reason as to how and why they would exist. As far as I could see, none of the answers in the other question covered this. [Answer] It is certainly possible and there are numerous real-world examples of the types of organisations you are looking for. Some examples: ## 1. [The Hashashin](https://en.wikipedia.org/wiki/Assassins) The original organisation of assassins led by a Grandmaster, known only as the Old Man of the Mountain, held several mountain fortresses throughout Persia and Syria. They carried out missions of espionage and assassination for over 300 years, successfully targetting influential figures including caliphs, viziers, sultans and crusader leaders. The first and most famous of the Grandmasters was Hassan-i-Sabbah. This organisation has been widely popularised by games such as Assassin's Creed and anime such as Fate/Stay Night. While the hashashin were a tightly organised group, they were spread out over several locations under local leaders, meaning your fictional organisation could develop conflicts of interest and infighting. ## 2. [The Teutonic Order](https://en.wikipedia.org/wiki/Teutonic_Order) Similar in nature to the Knights Templar, this order of knights was formed to aid Christian pilgrimages to the Holy Land but transformed into a military order. Eventually growing large and powerful (despite numerous defeats and changes of location), they conquered and ruled over large swathes of Poland, Lithuania, and Prussia. The order absorbed several other subsidiary groups of knights including the Livonian Order, which led to recruits coming from all over northern and central Europe. This led to the order's eventual downfall through political and military infighting, while the local populations united and overthrew their military overlords. They appear in various computer games (Medieval: Total War, Age of Empires, Europa Universalis, and Assassin's Creed), books (Conrad Stargard science fiction series by Leo Frankowski), and films (Alexander Nevsky, the 1938 film), and are commonly depicted as brutish and brutal. [Answer] The simplest way is to have the organisation be a loose collective. Each master will train apprentices, when some of those apprentices become masters some inherits the previous masters school but some others go out into the world to set up their own. Some of the new schools flourish, some don't. Over time similar (but maybe slowly diverging) classes grow up and study in each of these schools. Sometimes the split is amicable and the school and masters remain friendly. Sometimes it is anything but and anything from bitter rivalry to full on enmity springs up between these schools. [Answer] **You only need time, not guilds or worldwide schools.** Lets take DnD as an example since I've played it on and off since 1978. The earliest versions of DnD assumed a great civilization sometime in the very distant past. **Wizard:** There must have been someone a long time ago that either developed study based magic or received it from some outside source. He/she would have taught it to a few people. Whether there was a formal school or not is largely irrelevant. Since magic was useful, people learned it and the study spread, often with distinctions of various flavors as people learn different portions of the available knowledge depending on circumstances, skill and interest. Fast forward to "modern" times and you have wizards most places that have a large enough population. **Cleric:** Clerics worship various deities. Presumably, it is difficult for a deity to show up and offer power for worship. So we can posit that they show up in only few places on the world and convert a small group each time. The worship spreads like a virus across the world (small pockets of worshipers who send out people to convert other small pockets). **Fighter:** This is the first class that has a real world example. Just look at any weapon wielding group on our history. The club, sword, axe, and bow have sprung up multiple times in multiple forms as materials become available just because they are good tools for what they do. Sword techniques, for example, develop to take advantage of the shapes of the various swords. They can spread where ever the sword style goes. It may also be developed spontaneously whenever a sword style is common. There don't need to be specific guilds. **Rogue/thief:** Like in the real world, these skills can develop several times in different areas. Where ever someone has something that someone else wants, people will learn how to get it. There are other classes that are either similar to the above or combine lesser versions of the above with something else. These are all variations that can be spread with sufficient time. [Answer] In a comment, you ask > > How does an organisation exist which trains people to fight but doesn't instil them with any allegiance? > > > That's easy: mercenaries. A prime real-world example of what you are asking are [Swiss pikemen](https://en.wikipedia.org/wiki/Swiss_mercenaries). According to wikipedia, > > Until roughly 1490, the Swiss had a virtual monopoly on pike-armed mercenary service. > > > So there you have it: people with a specific fighting skill set and no allegiance but money. I think I remember having been taught in school (I'm from Switzerland myself) that Switzerland decided to prohibit mercenaries because Swiss-on-Swiss battles happened too often, which is one of your criteria, but wikipedia disagrees, and cites "Cambridge Modern History, Volume 1: The Renaissance" as a source. Anyway that's quite a small leap to make. [Answer] In my story, Classes exist as a blessing from an angelic being named Rorjon. As incredulous (or should I say fantastical?) as this is, I might be able to use that to help you out. In the world of Alendyias, Classes are determined by personality, or by how someone was raised. They're very much a product of society, but they're also unique to an individual in a way because in the end, they're determined by an individual's nature and personality traits. If you think about it, job choices or the occupation you're born with (as is often the case in fantasies) are the same way. Each Class has a certain skillset, a certain way of life so that almost covers "training in various combat techniques known only to the organization." As for "Members can come from a variety of nations, species and backgrounds and will not always follow the same leaders. They can end up fighting each other on different sides of a battle or war."....Alendyias covers this perfectly! It's one big world made from worlds fractured and reformed by a rent in reality itself, so all sorts of species, nationalities, and individual variations end up in one Class. However, since Classes are so powerful and influential, that covers "The organisation should be reasonably large. While individual masters training apprentices in the wild works for some classes, for others I would like them to be more numerous then this method would easily allow." Why? Well, since artisans formed guilds, it makes sense that Class-holders will form guilds for the same reasons they did: the benefit of mutual aid, maintenance of production standards, reduced competition, and political influence. The Guilds will help its members, because they *will* be held responsible by its members. Over time, these Guilds will evolve into powerful organizations in their own right, for the benefit of their members and therefore their own (if they don't help out the next generation, their Class will suffer, and people will go to great lengths to preserve their way of life, their traditions, and that means passing them on). "The organization may have some kind of fixed settlements or buildings where members are trained (though this is not essential)"? Great! Since every Class contributes to society, of *course* there will be buildings built for that exact purpose, same as there are schools in our day. In other words, when education is essential to survival, chances are there will be a place made for it. Hope this helps! ]
[Question] [ **This question already has answers here**: [Which goods make sense to transport over interstellar distances? [duplicate]](/questions/45472/which-goods-make-sense-to-transport-over-interstellar-distances) (26 answers) Closed 6 years ago. Information behind the world I'm building: FTL interstellar travel moves at around >1 light-year per day. Most interstellar planets are several tens of light-years distant. There aren't a great deal of interstellar worlds. Around >20. Information travels much faster than crew and cargo. Around 3 light-years per hour. Interstellar travel is fairly cheap. Larger corporations can afford it. People live a great deal of time. Several centuries. Interstellar, populated worlds are no where near as industrialized as Earth. They are in the beginnings of terra-formation and civilization. Mainly, what kinds of raw or manufactured materials are worth shipping across stellar distances? What sort of things could one solar system lack and another have in abundance? What kinds of trade were used in other star-spanning sci-fi or fiction stories? [Answer] **Recipes** Wait, what? Yep, recipes. And I don't mean **just** food items either. I'm talking about blueprints, schematics, and plans for technology items. They're not heavy, don't take up much room, and can be quite valuable. Depending on the relationship between any two planets, it could be a licensing deal (ie selling permission to use for some time), or a one-time deal (permission to use forever). The latter, of course, would be much more expensive. But if the two planets don't have any kind of patent reciprocity, it's the best you can do. Now that it comes up, don't forget actual, well ... recipes. If the locals on a remote planet have similar preferences, you could sell the recipe for tollhouse cookies, and make a bundle. Or the almighty apfelstrudel... ;D **Update after comments** The reason to bring the information in person (I should have expanded on this earlier) is that in many cases it will be difficult to actually implement the technology even with instructions. I'm envisioning a clan of space-gypsy general consultants who sell the information and then stick around long enough to help the customers through the growing pains. If the tech you're selling isn't a small incremental improvement on what the customer already has, they'll be glad you stuck around. Imagine you're selling them advanced battery technology. The customer will do better if you help him through setting up his factory. If he goes it solo there will be way more explosions per capita than if you stay. Not to mention you'll want to stay on the foreign planet for a while to investigate what **they** have that you can bring back to your planet. You'll need some training before you can adequately sell what they have. And, of course, you can be carrying psychoactive spices, gold, nutmeg, or tulips in the hold of your ship as "ballast"... ;D [Answer] In any colonization, development, and trade scenario there will likely be some version of local "unobtanium". We have plenty of iron but not enough tin, manganese, indium and vanadium to make certain alloys. Certain families of symbiotic bacteria die off easily because the bright line spectra of the local star has one or two more bright lines than good old terra. So fertilizers AND pro-biotics are necessary to grow crops. Or maybe there is no local conditions suitable for growing coffee or cocoa. (Would anybody really live there? I wouldn't without coffee/chocolate imports!) And as long as you are world building, it is pretty easy to imagine if someone thought underwriting colonization cost was worthwhile, then this place also probably has something unique worth shipping out as its own trade goods. Freight companies hate deadheading. (a term for paying the cost of fuel to carry an empty cargohauler.) [Answer] > > What kinds of trade were used in other star-spanning sci-fi or fiction stories? > > > The spice must flow. [Answer] The answer to your question depends strongly on how expensive an interstellar voyage is. If star ships are comparable in price to buy and run to large container ships then you could expect what we see in sea cargos – almost anything. If the costs are more like those for aircraft then the goods would be restricted to higher value items. If the costs were more like those of running a current day space craft then the goods would be very limited to the highest cost technology and absolute essentials. [Answer] People - Immigrants from neighboring planets that each have a personal story as to why they want to move. Technology - The different systems could be at varying levels of technological advancement, and societies could trade differing inventions and applications of resources. Manufactured Goods - Where one civilization is suffering from a lack of certain material, they would probably be very eager to trade with a different civilization who had the resource and used that material to create products. Products will need circulation, even interstellar. And of course, Resources- Each planet is only going to have a certain amount of a certain material, and as a species advances, resources are spent. As to what materials, it would just be varying amounts of the basic elements and certain compounds, depending on the planet's location and environment. [Answer] # Look at Shipping Costs, not just Shipping Times Assume that *refined unobtaininum* is 5% cheaper in system A than in system B because it is more abundant, and that the manufacturing process wastes 5% of the material (recovery is not economical). You need *unobtainium* bolts in system B. Do you take local *unobtainium* and manufacture the parts in B, do you import *unobtainium* from A and manufacture in B, or do you import manufactured *unobtainium* parts from A? Depends on how much the shipping costs. # Then there is [Comparative Advantage](https://en.wikipedia.org/wiki/Comparative_advantage) Say system A (with some *unobtainium* deposits) has an airless world, a couple of gas giants, asteroids, etc. They have no world that would be habitable in shirtsleeves. Growing grapes to make *good* wine is difficult. System B has both a nice world (again with some *unobtainium* deposits). Again you need *unobtainium* bolts in B. System B could produce them domestically and system A could grow their own wine. But if transport is cheap enough, then **both will benefit** if A makes *unobtainium* bolts for both systems and B makes wine for both systems. (How exactly the benefits are split depends on exchange rate mechanisms.) [Answer] # Culture [![enter image description here](https://i.stack.imgur.com/GLGTr.jpg)](https://i.stack.imgur.com/GLGTr.jpg) *Holographic Art Center ([Image Source](http://holocenter.org/artgrants))* A roll of toilet paper is a roll of toilet paper no matter where you make it. But **culture** is always unique. Hence **culture** will need to be traded if you want to experience it in a place separate from where it was created. For example... * Music * Drawings * Films * [Carvings](https://www.youtube.com/watch?v=1AIjEsIOAQY) * Hologram sculptures * [ASMR performances](https://www.youtube.com/results?search_query=asmr) * Scent programs * Emotion recordings * [Memory vacations](https://en.wikipedia.org/wiki/Total_Recall_(1990_film)) In short: **anything that is created by an artist**. The culture-wares can be both tangible and intangible. The point is they need to be moved from the artist to the consumer since that same piece cannot be created locally. [Answer] **Diamonds** [Carbon Planets](https://en.m.wikipedia.org/wiki/Carbon_planet) are a theoretical type of exoplanet that has an abundance of carbon. As a result, it's been theorized that such a planet would be rich in carbon containing compounds like diamond, graphite, and hydrocarbons like crude oil, tar and methane. Probably a good place for a manned mining station, but carbon planets will likely not have oxygen atmospheres or water, so that's something to keep in mind if your people are only just starting to terraform. It would likely be an engineering challenge. [Answer] Bitcoin! Cryptocurrencies are solutions to NP problems which cost energy and other resources to solve. They can trade the solution to such problems. Anti-matter is very expensive to produce to. So are heavy elements in large quantities. Gold is rare, everywhere! ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- Closed 6 years ago. * This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). * 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). [Improve this question](/posts/94689/edit) Let's say it's NASA. What could happen if after takeoff, when there's no turn around, the astronauts found a human stowaway? Some things to look at; It takes millions of dollars to carry out a space mission, possibly more depending on how far they're going. The person who is a stowaway is 120 pounds and is a complete stranger to the astronauts or anyone at NASA. Also: (curious but don't need to be answered, the question in the title is most important so just overlook these if you want) * The plausibility of the astronauts deciding not to report the stowaway until they returned, * the possibility of them surviving if it's a long term/permanent (as in going to Mars or something to colonise)/ or short term mission, * and the overall possibility of it happening in the first place. [Answer] It really depends on when the crew discover the stowaway. I would bet, though, that they'll choose to restrain the person, report the incident to Mission Control, and then, after talking with Mission Control, abort the mission. Reasons for aborting: * The person could be trying to sabotage the mission and/or hijack the shuttle. This could be especially worrisome if the payload includes a military satellite. * The person could have already sabotaged the shuttle or placed a bomb on board; if possible, the crew (and the payload!) need to be gotten somewhere safe. * Having another person on board means that the crew may have fewer resources. * Doing otherwise could have a negative psychological impact on the crew members. # Shuttle security breach The plausibility of a stowaway, as others have said, is doubtful. It would very difficult for the person to board the shuttle at all; it's a few orders of magnitude harder than breaking into a car, for example. Post-9/11, [public access to Kennedy Space Center was restricted](https://www.scientificamerican.com/article/nasa-grapples-with-us-space-security/) around the time of shuttle launches. In the first mission or two after the attacks, even the planned launch time was kept secret, meaning that this would-be stowaway would have to either be on the inside (which would help with other aspects of the plot) or be a very good guesser. Even then, the launch could be scrubbed and moved back because of things like inclement weather. The person could be kept hiding for days, likely with minimal provisions and supplies. Military personnel have often been used for security (for instance, [before *Columbia*'s final mission](http://www.nytimes.com/2003/01/13/science/security-tight-for-space-shuttle-and-first-israeli-astronaut.html), because Israeli astronaut Col. Ilan Ramon was one of the members). We're not talking about a few security guards with nightsticks; we're talking about military-grade weapons used by the actual military. # 1. T-0 to T+8:30 In this case, you probably want to abort the mission as soon as possible. Someone unknown is in a spaceship and could have a weapon, bomb or other harmful device. They could hijack the mission and cause serious problems. There's very little this person can do in the early stages of the launch, so that's when the crew need to act. Once the solid rocket boosters (SRBs) were ignited, [no abort could be performed before SRB separation](https://en.wikipedia.org/wiki/Space_Shuttle_abort_modes#Ascent_abort_modes), roughly two minutes into the flight. After that, there were several abort options[[1]](https://space.stackexchange.com/a/10605/5963), [[2]](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015564.pdf): * **Return to Launch Site (RTLS)**, involving jettisoning the external tank and landing at Kennedy Space Center. * **Trans-Atlantic Abort (TAL)**, involving jettisoning the external tank and landing at one of a number of sites in Europe and Africa. * **Abort Once-Around (AOA)**, involving a modified flight pattern circling Earth once before landing somewhere. * **Abort To Orbit (ATO)**, involving reaching a lower orbit than intended. The optimal options here are RTLS and TAL. AOA only had a *very* tiny window in which to initiate, and ATO meant that a modified mission will still go on. RTLS and TAL meant that the Shuttle could land very quickly and stop the mission. # 2. T+8:30 onward [Main Engine Cutoff (MECO)](http://www.daviddarling.info/encyclopedia/M/MECO.html) occurs at T+8:30. After this point, the crew likely can no longer perform an RTLS or TAL abort. An AOA abort would get them back to Earth, but again, that might be hard to do. What the crew *can* do is go into a modified orbit, using an ATO abort. If they're already in orbit when they discover the stowaway, of course, then they'll stay where they are. So, they're now stuck in a spacecraft with an unknown person - again, potentially harmful. Their course of action depends on what the mission is. It could be any of a number of things, including * Going to the ISS or another space station. * Launching a civilian satellite. * Launching a military satellite. * Repairing a satellite or telescope (such as *Hubble*). All of this takes time. If the crew has performed an ATO abort, though - which they likely have - then the mission is compromised. They could move to a different orbit, yeah, but there's already a wrench thrown into things. Who wants to launch a satellite with a potential psychopath in close quarters with you? The point is, the best thing to do is go into a lower orbit and do a final consultation with Mission Control before returning to Earth with the mission incomplete. Better safe than sorry. [Answer] It wouldn't compromise the mission, since these systems are engineered with a lot of "excess capacity" in case something goes wrong. The big issues would be regarding room in the "cabin": it's going to be *pretty darned small* to begin with, so the possibility of there being a place for the stowaway to hide is somewhere between zero and none. EDIT: the stowaway might actually compromise the mission if the extra mass causes the vehicle to be placed into slightly the wrong orbit. That's because -- even now -- if a rocket's second stage engine cuts off just a *couple of seconds* too early, the satellite can be placed in a wrong orbit. If the on-board computers were to chat with ground radar and discover that it's not going as fast as it should, then it *could* burn the engines longer, but I don't know if that's what happens now. EDIT 2: Space Shuttle missions had *Safe Haven Food*, which was an extra 22 day supply of food/water, and the ISS has much redundancy (including food/water). <https://www.nasa.gov/audience/forstudents/postsecondary/features/F_Food_for_Space_Flight.html> <https://www.space.com/29266-one-year-iss-crew-member-talks-cargo-ship-failure-video.html> [Answer] The most probable outcome is that the astronauts would still report the stowaway. Since this is NASA, it should already be highly unlikely that there are any stowaways in the first place, as protocol and procedures are very strict and should always be followed. Unauthorized personnel should never be allowed in the first place. What would happen if there was however, and the craft had passed the point of no return, it would be by circumstance that the staff in the craft will have to take the stowaway in. Every pound in a space craft is important because the amount of fuel needed to get the craft to lift off is perfectly calculated though, so there would be a chance that the craft failed to take off in the first place. But since the craft got into orbit anyway, I'm assuming weight is not a problem in this scenario. What would be a problem though is training. It takes years for one astronaut to be trained well enough to even get in a space craft, and since this stowaway is a complete stranger and is not used to a zero gravity environment, the most probable outcome other than the stowaway being taken in is that they will die during the trip or in any other point in time due to the body not being used to the environment. [Answer] One thing that will be difficult in getting a stowaway onto the shuttle is getting to the shuttle in the first place... Once on the Launch Padd, it's monitored extensively and the shuttle is normally out there for 48 hours before the launch... plus the time on the crawler where it is pretty much inaccessible. Access into the shuttle is very restricted once on the launch padd for a number of reasons, among them, the fact that the slightest bit of dust or hair could float into equipment and cause problems means that they are pretty clean room environments before the orbiter (the white plane like component of the shuttle) is fitted to the entire launch assembley (called the Shuttle. The rest are the two Solid Fuel Rocket Boosters (SRBs) and the External Tank (ET).) And it takes about two days to get from the assembly building to the launch pad by crawler... during this time, you can't get in, because there is no access to the door. Again, once there, it's fueled for 48 hours and again, the door isn't opened or closed at this time, to preserve the clean room... Any unknown opening would probably trigger some alarm as the door of a space craft can't just open because of the breeze... and any alarm will shut down the launch clock until it's figured out what is going on. Astronauts only enter the craft about 2.5 hours from launch, and that close, the shuttle is monitored even more closely. The total launch assembly has theoretical yield comparable to that of the Hiroshima Bomb when fully fueled and for that reason, NASA has a 3 mile radius ground clearance from any critical facility and a further area that is controlled to public access (you can tour facilities inside this area, but they are controlled more than the main visitor facility and they do close them off to the public during the launch). So in essense, to stowaway, you must make a three mile run through highly controlled access area, get into a sealed vehicle without tripping any doors, do so before the astronauts board, remain hidden for that time until they do board, and remain hidden for a further 2.5 hours plus the additional 8.5 minutes before main engine cut off to pull this off. Unless you have a NASA reason to be that close to the shuttle, you can't get that close at all. [Answer] The stowaway is not going to die. The astronauts are not monsters. If they have to throw stuff off the craft to meet the weight limit, they will throw away the least vital equipment. The stowaway is unlikely to die simply because they aren't as fit as the astronauts. The maximum amount of force due to acceleration is 3G (three times earth's gravity) at take off. <https://www.physicsforums.com/threads/acceleration-of-space-shuttle-at-liftoff.224305/> That's easily survivable by most people without medical conditions. The stowaway will have more muscular degeneration problems when they return to earth because they aren't as fit. There probably isn't an extra empty chair for the stowaway to strap into when they re-enter the earth's atmosphere. However, there is always extra oxygen in case a problem develops with an oxygen tank. Food can be rationed. The stowaway isn't going to have any fun. The astronauts are DEFINITELY going to report the stowaway. The stowaway might initially think along the lines of: "Look at me. How cute and funny I am being." The astronauts, by contrast, belong there. It isn't funny or cute for the astronauts. Who knows if this stranger messed with important equipment? Did the stowaway bring anything dangerous on board? What if this person gets injured or injures someone else? Imagine if you worked at an amusement park and if you caught some random person wandering around the amusement park after it closed. You'd not find their antics very funny. You'd be alarmed. NASA has protocols for dealing with crazy astronauts in space. The other crewmembers use duct tape on the wrists and ankles. They then tie the person down with bungee cords and give them tranquilizers. <https://www.cbsnews.com/news/nasa-has-plan-if-astronauts-lose-it/> That's probably what they would do if they didn't trust the stowaway not to press buttons. At best, the stowaway would be forced just to sit quietly and not touch anything. This defeats the purpose of going into space. It's unlikely that someone would be able to stowaway. There isn't a lot of space (and certainly not extra human sized cavities of unused space.) Also, part of the pre-flight checklist is to check all the hardware system on board. <https://www.wired.com/2010/05/process_shuttle/> It would be difficult for engineers to somehow miss a hidden person when they are checking every piece of equipment on board. Finally, the stowaway is going to be arrested and charged with criminal trespassing when they return to earth. [Answer] Most probably the astronauts will have to deal with someone has the worst case of space sickness. The sheer delight of having the stowaway vomiting copiously and regularly. If everybody is exceptionally lucky, the stowaway won't be affected by weightlessness, but that seems very, very improbable. The astronauts will report the stowaway. The mission will continue under severe constraints. It won't go to Mars or anywhere in the solar system (except back home to planet Earth). Stowaways on the space shuttle are extremely unlikely. Strangely, NASA isn't stupid. They make access to the space shuttle extremely difficult unless you have an authorized reason for being there. Therefore, an unknown person won't have a chance of getting on board. Oh yes, there is the distinct possibility the stowaway will be injured during lift-off. Experiencing high g-forces, while not properly seated or secured, has a definite risk factor. In summary, the astronauts should be delighted to find they have a vomiting medical emergency in the form of a stowaway. A person who has no training or expertise in space travel or the requirements of a space shuttle. Just the thing to ruin a good space mission. To say nothing of all the extra cleaning up they will have to do. Provided they don't succumb to the temptation of pushing the stowaway out of the airlock. :) [Answer] They would abort the mission. Current spacecraft carry supplies sufficient to support the crew on board with a safety reserve. These include the lithium canisters needed to remove CO2 from the air inside the spacecraft, without which the astronauts would pass out and die from too much CO2. An extra person would pose a problem for CO2 removal, as there would now be more CO2 to deal with, meaning the lithium scrubber canisters would be saturated sooner. This problem was encountered on the Apollo 13 mission, when three astronauts were packed into the LEM, whose lithium canisters were only planned for two people. They did manage to adapt the CSM lithium canisters when the LEM canisters were exhausted, but this does illustrate how carefully keeping people alive in space is planned. [Answer] Unfortunately, there is precedent. See "The Cold Equations" by Tom Godwin. Story has to do with a girl stowing away on a medical transport moving emergency supplies to an outpost threatened by disease. Fuel and time are at a premium, and the longer the extra weight throws the ship's trajectory off, the harder it'll be to get to the planet on time... You can see the story here: <https://photos.state.gov/libraries/hochiminh/646441/vantt/The%20Cold%20Equations.pdf> ]
[Question] [ In a setting where children begin training at a very young age, raised to be powerful warriors, it comes to reason that some weapons are more popular than others. People are trained to be able to fight against a vast variety of monsters (not other people), so obviously they would spend their time training with an actually useful weapon. It's not about the aesthetic appeal (though that's always a plus) but the practicality. I'm currently equipping all of my characters and am running out of ideas. It's a modern setting, and so guns are available, but not necessarily more efficient since many monsters are either magically armored or invulnerable save for specific weaknesses. Also, since fighting many monsters at once is a common occurrence, they would need to be able to carry enough ammo and reload in seconds. There is also a magic element (including children of Hephaestus, god of the forge) so it's possible for weapons to be slightly magical/unrealistic. The only other criteria is that the fighter can be versatile, since they fight a vast variety of different magical beasts. Assuming that every weapon that can feasibly exist is available, and the character is proficient with their weapon/s, what are some unique/likely possibilities and/or combinations? Would swords be the way to go? Is it conceivable that some might fight with chakrams, whips, urumis, maces, etc? This is my first question on this site, so if I did something wrong please let me know for the future. **Examples of monsters** (per request): There's a race that's a mix between octopi and spiders. They're big (size of a horse) and resemble giant spiders in shape and appearance but their legs are malleable and prehensile like octopus tentacles. Their mandibles carry venom and most of their internal organs are located by their underbelly. They fight in hordes. Another race that's invulnerable, humanoid shaped, commonly 9 ft tall. Their only facial feature is a red string stitched like lips. The only way to defeat them is to tear away the red string, force open it's jaw and destroy its heart, which sits on its tongue. Monsters that are like living shadows. They are intangible in the dark / dim light except for their teeth and claws, so they can touch you but you can't touch them. In the light, they become tangible. Of course, they only come out at night. Fight in hordes. A beast with the head and limbs of a panther, and the body of a giant snake. It can fly, whip it's tail faster than a whip, and twirl it's body so quickly it's like a drill. They fight by flailing their bodies / slamming into their enemies, and dive from the air to each strike it's victim or burrow into the ground and emerge beneath its victim's feet. They're scales can't be pierced, but can be loosened / knocked off, revealing the vulnerable flesh underneath. Thus, you need to hit them twice in the same spot, or pierce it's eyes or into its mouth. [Answer] > > There's a race that's a mix between octopi and spiders...They fight in > hordes. > > > Chain-fed machineguns. > > Monsters that are like living shadows. > > > UV lights. Note that real-life UV lights of significant intensity require a substantial power source. So, soldiers fighting these might be using vehicles carrying a large Li-ion power supply. > > Another race that's invulnerable, humanoid shaped, commonly 9 ft > tall... The only way to defeat them is to tear away the red string, > force open it's jaw and destroy its heart, which sits on its tongue > > > Explosives will dislocate the jaws and destroy the hearts. If for some reason they don't also shred the threads, mix in some incendiaries. > > A beast with the head and limbs of a panther, and the body of a giant > snake... They're scales can't be pierced, but can be loosened / > knocked off, revealing the vulnerable flesh underneath. > > > Explosives again. Grenade launchers sound good for using multiple blasts to concussively remove the scales. A [Mk 19,](https://en.wikipedia.org/wiki/Mk_19_grenade_launcher) perhaps? [![enter image description here](https://i.stack.imgur.com/p0e3p.jpg)](https://i.stack.imgur.com/p0e3p.jpg) [Answer] There's one big consideration you haven't named yet: what is your balance between practical and awesome? If you're going for practical: keep it simple. Traps, nets, ranged weapons and long pointy objects are your friends. Don't mount heroic expeditions with some chosen few. Instead, bring enough force and tools to squash the bugs like it's another day at the office. Think like the US army: if your monster hunt doesn't involve massive explosions, you're doing it wrong. When going the awesome-but-impractical route, all bets are off. Here you should treat it as a competition in scoring awesomepoints. Overcomplicated plans, hyper-specialized, and/or ridiculously oversized weapons, and contrived reasons why you can only have six people in your party. [Answer] Have you considered ## Polearms or Long weapons? Like [Halberds, Spears, Staves](https://en.wikipedia.org/wiki/Pole_weapon)? I think this type of weapon can be effective in battling multiple monsters. If you watch kung-fu movies, you can see many examples of this 1 vs many scenario. I think swords are too short and will leave a lot of openings on your characters especially fighting hordes. I think **Greatswords** will also work. Basically, you can go rampage without them coming too close to you. *Just gonna leave Guts here from Berserk* [![enter image description here](https://i.stack.imgur.com/JJWvb.jpg)](https://i.stack.imgur.com/JJWvb.jpg) More of his weapon, The Dragonslayer [![enter image description here](https://i.stack.imgur.com/hnf2U.jpg)](https://i.stack.imgur.com/hnf2U.jpg) [Answer] One of the reason there are so many weapons developed throughout history and across cultures is each weapon is designed to defeat a particular defense. Consider that European swords in the Middle Ages evolved from arming swords (the sort normally seen in television and movies), to "hand and half" swords to provide extra leverage and striking power as mail armour gradually was supplemented by plate armour, and then into long, stif rapiers to penetrate the gaps in plate armour, since the edged strike with a sword was no longer effective. To deal with plate armour, polearms provided extra leverage while smashing weapons like maces and hammers were developed to supplement or replace swords. Larger swords were developed to cut into pike squares, while the swords of other cultures (like Japanese Katanas) were designed for the particular conditions encountered there. [![enter image description here](https://i.stack.imgur.com/PpIE9.jpg)](https://i.stack.imgur.com/PpIE9.jpg) *Arming Sword* [![enter image description here](https://i.stack.imgur.com/H69UU.jpg)](https://i.stack.imgur.com/H69UU.jpg) *Hand and Half sword* [![enter image description here](https://i.stack.imgur.com/Re0qD.jpg)](https://i.stack.imgur.com/Re0qD.jpg) *Left to right, Longsword, Estoc (heavy thrusting sword) and Rapier* So without knowing what sort of monsters you are fighting, there are very few "generic" choices. Even firearms are designed for particular conditions or targets. Consider that in zombie lore, you need a 12 gage shotgun rather than a 5.56mm M-4 assault rifle, while long range targets need larger calibre weapons, or large and armoured targets need very high energy rounds (.50 cal or "elephant gun" rounds). I suppose if you are in unknown territory and have only one weapons system to choose from, go for the Winchester Model 1897 "Trench Broom". It is a 12 gage shotgun (use 00 magnum shot for maximum energy transfer), comes with a "sword" bayonet if you have to stab or slash a target, and the weapon is made with hardwood furniture so in a pinch it works as a club. [![enter image description here](https://i.stack.imgur.com/XdMCx.jpg)](https://i.stack.imgur.com/XdMCx.jpg) *Winchester Model 1897 Trench Broom* [Answer] With fighting a monster, the key is to keep the monster away from you. You never want to go toe to toe against something stronger and faster than you. Traps are the most logical weapon followed by range weapons and then long melee weapons such as pikes. Swords would be a weapon of last resort [Answer] Keep it simple use the most deadly weapon in human history. **The spear.** Don't need to be organic material with high technology material it could be possible to have very long spears - or even telescopic spears. The warrior can anchor it in the ground and let the monster come so the momentum of the charging beast will drive the blade into its belly. Or with a shorted handle it could be used at close range fighting multiple targets. Last not least combine the spear with a gun... HaHa why not take the best from everything - Adeptus Astartes Boltgun + Sword + Mace + Spear = this sketch (1h work) [![enter image description here](https://i.stack.imgur.com/u6r7V.png)](https://i.stack.imgur.com/u6r7V.png) ]
[Question] [ I am currently writing about a military society that enforces its subjects using *Acer*-class airships. Picture the [USS Iowa](https://en.wikipedia.org/wiki/USS_Iowa_(BB-61)), except flying and with enough supplies for a year in the air. The only warning sign of their approach would be a disembodied shadow speeding across the ground (because it used active camouflage to blend into the sky). My question is: **Is it possible to camouflage even the shadow**? [Answer] Camouflage seldom truly attempts invisibility, instead aiming to break up patterns so that what you see isn't recognizable as a threat. In that vein, [Diffused lighting camouflage](https://en.wikipedia.org/wiki/Diffused_lighting_camouflage) has been in use for aircraft since World War II, and is seen in submarines and squid underwater. For aircraft, the common system was [Yehudi lights](https://en.wikipedia.org/wiki/Yehudi_lights). Because it is difficult to replicate the sheer energy of the sun, you likely would not have a complete lack of a shadow, but the shadow would be less likely to look like an aircraft, and more likely to be disregarded as a fast-moving cloud, or a passing flying animal. [Answer] The only true way to eliminate a shadow would be to cover the airship in a "[metamaterial cloak](https://infogalactic.com/info/Metamaterial_cloaking)". These are carefully engineered materials which force light to refract or reflect in ways the engineer intended, rather than following the simple optical pathway (this works with other waves, metamaterials can be engineered to refract microwaves or even sound). A properly engineered metamaterial cloak could cause the light rays to literally refract all the way around the object, not even leaving an optical "hole" to demonstrate something is there. [![enter image description here](https://i.stack.imgur.com/9ePIV.jpg)](https://i.stack.imgur.com/9ePIV.jpg) [![enter image description here](https://i.stack.imgur.com/pTMGB.jpg)](https://i.stack.imgur.com/pTMGB.jpg) *Two illustrations of how a metamaterial cloak would work* There are a few difficulties with this approach, however. Firstly, metamaterials are carefully engineered for a particular wavelength or frequency band. It isn't clear that you could make a metamaterial cloak which would refract 100% of visible wavelengths so you might end up with a ghostly image in (*say*) the red end of the spectrum, while higher frequencies like blue would be refracted around the object. This also means you would still be visible on radar or using a laser rangefinder once the frequency band is known. Secondly, for an airship this would add considerable weight, yet be a delicate coating (much like the special coatings on stealth airplanes need frequent and specialized maintenance). The ship might spend a lot of time on the ground being checked out and resurfaced in order for the coating to work at optimum efficiency. Lastly, a 100% effective metamaterial cloak has the disadvantage of preventing you from looking out. While active sensors like radar could likely penetrate the cloak and receive a return (although the appearance of an unidentified radar emission in an otherwise empty sky would alert a lot of unwelcome attention), passive optical sensors would not be able to "see" out of the cloak for the same reason you can't see into it. The airship will need holes in the cloak, or shutters to allow sensors or even the crew to look outside the ship. Every hole in the cloak is another potential way for the enemy to see you, and as an airship, you would want to have visibility across the entire sphere for protection and even simple navigation. So metamaterials are a clever work around to the idea of being "invisible", but there must be an understanding of the limitations so you can make reasonable choices in how to use them. In any semi modern seeing, it may be more sensible to use a metamaterial cloak set to microwave frequencies to defeat radar, rather than try to be invisible to the naked eye. [Answer] Unless there is something that I am not seeing, the answer ought to be simple. Your airship should have a camera and sensing system on the top side and an array of lights on the other. The camera and sensing system takes in the position of the sun, the location and blockage of clouds or other objects above it, and then sends that data to a central processor. That processor takes the data from above and uses that data to eliminate the shadow through a combination of "sunlight" (sun spectrum) flood lights and projectors. Depending on the technology level of the world, and the technology level of this ship specifically, you will get different results. If you have a single two-state light sensor on top and a single incandescent bulb below, then the result will not be convincing. If you have an array of different light, uv, and ir sensors along with several cameras and an array of future-tech projectors on your vessel, then your results will be more convincing. Keep in mind that the shadow simply indicates that there is an object blocking a source of light enough so that you notice. Removing this shadow could be very expensive in terms of energy, but if you only wanted to make it non-obvious, I bet you could make ends meet. [Answer] **Height** If it keeps the same altitude that our comercial flights, it would need just some smart reflectors and some cloud hunting to avoid detection from most people, even the shadow is completly discarded to be notice. If the ship is soaring near the top of buildings (Shouldn't do it, thats why cazas and destroyers exist). It becomes complicated, not only has to mimic everything in top and around him without showing a huge thermal footpring but doing it in complete silence too. [Answer] I'm not sure what sort of *active camouflage* you have in mind, but there is one sort of hi-tech camo where this could be possible. [There is a concept designed at MIT where an object is covered in bristles (like a hair brush)](https://www.technologyreview.com/s/407677/how-to-make-an-object-invisible/), and those bristles bend the light around the object, by diffusion I believe. It's supposed to work from multiple angles, so wherever you are in relation to the object, the light and colours from behind are what you see in place of the object. It ought also, to bend the sunlight around the object and make its shadow much less noticeable. Excerpt from the article linked: > > To become invisible, an object must do two things: it has to be able > to bend light around itself, so that it casts no shadow, and it must > produce no reflection. While naturally occurring materials are unable > to do this, a new class of materials called metamaterials is now > making it possible. > > > ]
[Question] [ Human civilization really took off when individuals started to interact with each other, in language and trade and settlements. The transition from stone age to our space faring civilization of today wasn't as much a matter of sudden genetic mutation as it was a social organization realizing a latent potential. I hope there're no big disagreements about that so far. Regard dogs. Very social and somewhat malleable domesticated animals as we have bred them. What if we taught them to "speak" with each other? Not teach them to speak with us (like Dolittle), which all dog training to date seems to focus on. But to use our technology to create dog-to-dog-adapted multimedia user interfaces to facilitate the dogs' communication with each other. Creating a dog language for dog use. Even if we might not understand all of what they chat with each other using it. For them to create their own civilization on their conditions here among us. The dog-communicating civilization, as far as I think I know dogs, would probably focus on territory claims and social status and sex and food. There's no end to their interest in those topics (nor is it to ours). But who knows, maybe their perfect sense of smell and excellent hearing could contribute a for us completely new view of the world and even of concepts like mathematics, which humans developed out of geometry because our visual and spacial senses dominate. The dogs' civilization might surprise us in unforeseen ways. It might revolutionize social sciences more likely than natural sciences. Is it feasible to create a dogs' (or some other species') civilization by teaching them how to better communicate with each other? [Answer] # No, Dogs are pretty far from civilization Here is a short list of things that humans have and dogs don't. Most of these things will be limiting on dogs creating a civilization. * **Dogs don't have specialized language areas of the brain**. [Humans do](https://en.wikipedia.org/wiki/Language_processing_in_the_brain); no other animals really do. This is neuroscience, where little is known and less is proven, but it is generally accepted that there are specifically evolved areas in the human brain that allow us to process language. Without that part of the brain, even if you taught the dogs to talk, they wouldn't be able to process abstract thoughts and create new language for new situations. * **Dogs don't have vocal chords**. Humans have a [descended larynx](https://en.wikipedia.org/wiki/Larynx#Other_animals), and a tongue that can interact with the [pharynx](https://en.wikipedia.org/wiki/Pharynx) to produce a wide variety of sounds. In addition to the brain problems with language, it also doesn't help that dogs can't make nearly the variety of noises with the control that we humans do. * **Dogs can't operate tools**. No hands, mouth isn't that useful, etc. Tough to build a civilization without tools. Walking on two legs has its advantages. * **Dogs (probably) can't visualize a 3-d object in their head**. This is a little tricky, since I'm veering into neuroscience again. However, one of the key evolutionary developments of humans that apparently no other animals have is the ability to visualize objects that doesn't exist. This is a very critical skill for two things, to copy something you have seen before, and to invent something that you have never seen before. This was the key development between the [Oldowan and Acheulean](https://en.wikipedia.org/wiki/Stone_tool#Mode_I:_The_Oldowan_Industry) industries in paleolithic tool making. Where Oldowan tools were made by luck, Acheulean tools were made by design. Evidently, by ~1.5 million years ago, our ancestors became so tool dependent that there was evolutionary pressure for the brain to develop better ways to plan and manufacture new tools. Since chimpanzees probably can't do this, dogs almost certainly cannot. You can certainly argue that, using technology, we can insert enough microchips into a dog's brain to overcome these problems (although no hands still sucks). But, I would argue at that point, we'd have built AI's so powerful that we would be the pets, and dogs would just be the pet's pets. Unless AI's found us less likable than dogs (which seems true) and keeps the dogs as pets and exterminates us. Either way. [Answer] **Start with music**. from <http://www.halfbakery.com/idea/Crow_20Music#1096876393> This idea is based on the hypothesis that the ability to appreciate music emerged together with the ability to converse - music is the hidden sister of language. Conversation and music are similar in many ways. Meaningful inflections, changes of pace and volume, even word sounds are echoed in music, still carrying their connotations from language. It is sometimes hard to separate out the music of someone speaking in your mother tongue - your analytical brain keeps stepping forward to make sense of the words. This is somewhat less of a problem with foreign language. I posit that music is appealing because it allows the suppressed part of the language brain to step forward. Ok - so what? I propose that an effort be made to extract the music from the conversation. For human languages I bet this could be done by someone with a good ear and some practice. This person could help design a computer program. The computer program would then be applied to conversations between animals. There is no doubt that some animals communicate with language like sounds. Chimps and dolphins are two examples. I think crows may be another. With the aid of this program, species-specific music could be generated. You would need to take care that the full range of tone and infection was captured - not just what humans can hear. Computer generated music lacks the spark of real music, but it can sometimes come close. So you have crow music? Then what? I propose that listening stations be set up, with nothing more than a somewhat comfortable environment and the ability to play the generated music. Possibly there could be a switch the animals could trigger when they wanted to hear. Crows, chimps and dolphins all find pleasure in exercising parts of their brain outside of the context of survival - they play. If we get the music right, they should want to come and hear. The final goal? To make musicians. This is why crows are well suited for this experiment. There are millions of them. If one in a million has the brain hardware to not only appreciate our generated music, but to come up with his own, those crows should congregate around the listening stations, listening to the music we made and trading new music with one another. The same might be true for dolphins or chimps. Once these pioneers show it can be done, other individuals will join in. [Answer] There is a debate about what exactly "Civilization" means, but I'm in the camp that believes it is more-or-less synonymous with writing. So for me, this question devolves to, "What kind of 'writing' could dogs develop?" They don't really have the dexterity to manipulate a traditional writing implement, so that's out. They certainly don't have the dexterity to use a [woven system](https://en.wikipedia.org/wiki/Quipu), like the Andean civilization used. One thing that does occur to me is that dogs *already* do have one means of record transmission: scent. This is part of why they like close contact so much, and why they spend extra time sniffing a newcomer in greeting (particularly a family member who may have been interacting with a dog they've never met). I'm not sure how much information can really by translated this way, but at the least its like leaving a calling card. To build a true civilization out of this, you'd probably have to modify the dogs to be able to leave multiple different scents on demand. Another thing that occurs to me they *could* do for more permanent writing is use an impressed writing system, on specially-prepared soft ground, using their own paws to do the impressing. They'd probably have to use the orientation of the print to constitute different glyphs. Either of these options of course would require reorganization of dogs' brains to be able to process information this complex (assuming they can't right now). [Answer] We already have humans, whales, dolphins, bees and ants, each with their own distinct yet advanced communications methods. Soon we may have AIs chatting away to each other electronically. And you want to add dogs to the dialogue? What do you have against dogs? I mean really, what has language ever done for any of Earth's more communicative species? Humans have used it to build kingdoms, nations and corporations, so that they can justify slaughtering each other in wholesale numbers. Bees and Ants have used it to build rigid matriarchal dynasties with no career potential for the drone castes; and again, waged war on each other on a scale that makes humans seem peaceful. And the languages of whales and dolphins sound so mournful... I don't imagine that they are using their lingual calls to tell each other dirty jokes. Has the happiness of any species on Earth ever been improved by their learning to communicate with each other? Let's leave our usually happy, infinitely patient and forgiving, noble and loyal canine friends in their current blissful state; contentedly ignorant of the burdens of higher communications. They are already so much wiser and better than we will ever be... let's not mess up one of the best things our planet has created during this epoch. All kidding aside, teaching dogs to talk is not only a feasible idea, it is a spectacular idea! As the current stewards of this planet, one of the things we should be preparing for is our own retirement from that role. During the next several thousand years, we will either send our children up to the stars or lower our corpses into shallow graves. Either way, Earth will someday need new caretakers. ...and it is our job to start training our replacements. I think the Dogs would be an excellent choice for that role. ]
[Question] [ Building things in space is a massive benefit as the weightlessness and lack of stress means the only restraint is the amount of resources available for construction. But therein lies the problem, how do we move things economically into space? Assuming 22nd century technology or less, what is the cheapest way of moving large amounts of resources into space (think in the region of dozens of tons)? [Answer] The problem to solve is to both raise objects to orbital height and to impart enough momentum to achieve orbital velocity. Getting to space altitude isn't all that difficult, the V2 rocket could almost achieve the 100km altitude for reaching space with 1940's technology, and small craft like the X-15 or SpaceShipOne have been able to achieve this threshold as well. [![enter image description here](https://i.stack.imgur.com/Ig886.jpg)](https://i.stack.imgur.com/Ig886.jpg) *X-15* [![enter image description here](https://i.stack.imgur.com/iBGlu.jpg)](https://i.stack.imgur.com/iBGlu.jpg) *SpaceShipOne* Getting into *orbit* requires considerably more energy, since you need to be accelerated to a speed of @ 7 km/sec. The Russian R-7 was the first rocket to launch a satellite into orbit, and this monster weighed about 260 metric tons at launch, as opposed to the 12 metric tons of a V-2 at launch. [![enter image description here](https://i.stack.imgur.com/yThqa.jpg)](https://i.stack.imgur.com/yThqa.jpg) *R-7 launch* Physical structures like the space elevator, [Lofstrom loop](http://launchloop.com), [Space Fountains](http://www.orbitalvector.com/Orbital%20Travel/Space%20Fountains/Space%20Fountains.htm), [Startram](http://www.startram.com) and so on need to be incredibly massive in order to achieve the same goals as a rocket. This might be thought of as comparing a cross channel ferry with the "Chunnel" in terms of the amount of time, energy and resources needed. This also gives you an idea of what these ideas are up against; the Chunnel is thousands of times more expensive than a ferry, but can throughput a much greater volume of traffic, which means that the costs can be amortized over a large number of paying customers. At the current rate of space launches, there is no possibility of recovering the cost of a launch megastructure like Startram (which could possibly be built using near term technology), much less advanced concepts which still need extensive R&D like a space elevator or the Lofstrom Loop. Without a high demand, the price of space launch will not come down, but the sorts of megastructures that can bring prices down won't be built until there is sufficient demand.... [![enter image description here](https://i.stack.imgur.com/rCiA5.jpg)](https://i.stack.imgur.com/rCiA5.jpg) *Lofstrom Loop* [![enter image description here](https://i.stack.imgur.com/WxkIf.jpg)](https://i.stack.imgur.com/WxkIf.jpg) *Space Fountain* [![enter image description here](https://i.stack.imgur.com/bVHtc.jpg)](https://i.stack.imgur.com/bVHtc.jpg) *Startram* [Answer] Space elevator is the technology you are looking for. They are permanent structures lifting cargo up to space. It uses a climber car to ascend and quite efficient. Its construction is possible and even there are discussions we should start building one. You will simply need a material that is strong enough to resist tidal forces. Carbon nano-tubes can easily handle that load. For more technical details refer to this [***wiki***](https://en.wikipedia.org/wiki/Space_elevator) article. [Answer] ## Don't ship raw materials into space. Get the raw materials from space. Build it in orbit. Drop the finished product on the surface. Mine stuff from the Moon, or from asteroids. There's a lot of them, and there's (very likely to be) no life on them so there's no environmental concerns. Anything you have to ship can be done via two ways: Space Elevator, and a [Space Cannon company called Quicklaunch](https://en.wikipedia.org/wiki/Quicklaunch). [Answer] The key, in my mind, no matter what the specific solution, is that it's *reusable* and *capable of a high launch rate*. There is no inherent reason for, say, a space elevator to be cheap and for rockets to be expensive. There are essentially four types of costs to any launch system: Development costs, manufacturing costs, per-launch costs and 'standing army' costs. For a reusable system you can add maintenance. Development costs must be amortized by by doing a number of launches, manufacturing costs must be amortized by launching the same vehicle a number of times (or using the same structure, in the case of a space elevator or fountain, etc.). Standing army costs represent the people and equipment you need just to keep up the ability to launch. It might cost hundreds of millions or more per year just to keep up your launch capability, independent of whether you actually launch anything. This, again, means you need a bunch of launches or each one will be very costly. If you launch often enough and reuse your vehicle enough, then hopefully everything but the per-launch costs (including fuel, mission control, etc., all relatively cheap) will be minimized. If you have a space elevator that cost $20 billion to develop and build and costs a billion each year to maintain, and can only launch, say, five payloads per year, it'll be expensive for much of the same reasons our current rockets are expensive. Conversely, if it costs the same but lifts a payload every day it'll be cheap. So to answer you question, I think you'd be justified to pick any system that has matured and sustains a high launch rate. Take reusable rockets, a space fountain, whatever you like. One or more of them will have become mundane and commonplace in your setting, getting you the cheap launch you need. [Answer] In terms of realism, resources, and money, I think that using reusable shuttles is still the most cost effective way of getting stuff into space. I assume by this stage that some kind of renewable energy would provide the propulsive lift. Huge structures like the fountain and space elevator would end up be massively expensive and would require world-wide funding. ]
[Question] [ In the history of human construction, there are two kinds of concrete: Roman and Portland cement. Roman concrete was so durable that it'd helped the buildings of Rome survive for 2,000 years. Portland cement, by contrast, is so poorly considered that in a Life After People, moisture will weaken it into collapse after a century. Listed here are the ingredients for a different kind of cement: * Water * Sand * Mud * Manure * Clay * Chalk * Powdered limestone * Powdered shale * Powdered slate * Seashells * Volcanic ash With this recipe, would modern concrete be better off in a Life After People, or would it add to Portland cement's already apparent problems? [Answer] Concrete is not as simple as throwing a bunch of ingredients together. The ratio of the materials is very important. Thus, just a list of chemicals cannot tell us what will and will not work. From [this research paper](https://www4.uwm.edu/cbu/Papers/2003%20CBU%20Reports/REP-506.pdf), portland cement does just fine, if you mix it right: > > Most recently, Mehta and Langley 2000, designed an > **unreinforced, monolith concrete foundation consisting of two > parallel slabs, to last for 1000 years**. They used high > - volume Class F fly ash concrete in the construction of the foundation. The slabs were built with HVFA concrete mixture > containing 240 lb/yd^3 of Class F fly ash and 180 lb/yd^3 of portland > cement. Reinforcement was not used for these slabs. A petrographic > examination of one-year-old test slab that was cast and cured under similar conditions has shown crack > - free nature of the HVFA concrete (Asselanis and Mehta 2001). > > > At present, this seems to be achievable for concrete without > reinforcement to predict/speculate on a 1000 > - year life. > > > I recommend reading that research paper. In addition to suggesting portland cement can last 1000 years, it also runs down a lengthy list of characteristics for long lasting concrete which may be helpful to you! [Answer] Concrete is a composite of cement a binding agent and another material that provides the soft cement durability. For durability the key factor is maximizing the binding surface area between the cement and the additive. The first step is selecting an additive with large surface area. Romans used volcanic ash, the example in Cort Ammons answer fly ash. The function is the same, to increase the surface area the cement has to attach to. Generally "ash" is good since the properties that make us call something "ash" imply large surface area to mass ratio. (Most other things on your list are not that good as they have grains that either are worn round, have smooth surfaces, or both.) The second step is to optimize the ratio of cement to additive (almost certainly wrong term), cement is soft so if you have too much of it, the concrete will have bad mechanical properties. If you think about it, maximizing the cement to additive surface area means having the right ratio so that weak additive to additive contacts are avoided and that the amount of soft cement mass not in contact with additive is avoided. But it is not really this simple in practice, obviously. You have to also think about economics and the intended purpose and the types of loads on the structure. Large rocks with low surface to volume ratio almost always weaken the structure, but they can drop the cost without significant weakening if the concrete is only exposed to compression. The concrete around the rocks will still be weaker and crack, but cracked concrete still can carry weight if it can't move. A related issue is that if you want the concrete to have specific properties at scales much larger than the grain size of the additive, and cube-square law implies the additive should have small grain volume for optimal durability, you might want to, or even need to, use reinforcement. Reinforcement generally reduces long term durability due to stresses in the interfaces between the concrete and reinforcement and steel, for example, also corrodes. But people have been using glass or obsidian **fiber** reinforcement, which might be stable over long time. And of course if you want long life you also need to consider chemical stability. Usually this isn't an issue or the actual issues are hard to predict. For example Roman concrete is still vulnerable to damage caused by pollution that did not even exist when the buildings were built. Nobody blames the Roman architects for that oversight. (Although since you have "manure" on the list, you should remember that organic components or most cheap metals degrade over time and cause the entire composite to fail when doing so.) ]
[Question] [ I know that with a vacuum, you'll be able to gain a whole lot more lift than with any gas. I'm just wondering how you'd do it. What would be needed to make a vacuum balloon as opposed to a hot-air balloon? [Answer] The other answers discuss normal matter *physical materials*, where it seems unlikely to be possible or practical. However, that's not the only option. As mentioned on other posts ([shields](https://worldbuilding.stackexchange.com/questions/12520/hard-sci-fi-energy-shields/12527#12527), [super materials](https://worldbuilding.stackexchange.com/questions/29801/what-are-some-plausible-super-materials/29834#29834), etc.). I have been convinced that practical warm **superconductors** will be an enabling and transformative technology. Besides simply saying "build the ball out of the afore-mentioned supermaterial", this case is simple, and similar to the original application described for the technology in space construction: make a loop of superconductive rope and install a permanent current. Its self-magnetism will turn the wire into a hoop. The awesome thing about magnetic structures is that the strength is unlimited in the classic sense. Anything that would deform the structure applies energy that's used to resist the movement instead! A hoop, used to make a rib of a balloon, will distribute the pressure uniformly and have no weak point to fail at, since it's just magnetism and electric current. What's really cool is that the physical material is just flexible string. When turned off, it is shipped flat and folded into a compact container. To use, it is charged with electricity. Flux-pinning technology is used mount the balloons and other vehicle components together. [Answer] The strength needed for any material to sustain a vacuum in any meaningfull volume while at the same time keeping buoyancy in our atmosphere is way above current material technology knowledge. You need strong walls to hold a vacuum against the atmospheric pressure, at the same time you need light enough walls, so as to avoid adding weight to the system and end up having something that is still heavier than air. Buoyancy is achieved when the volume of the system vacuum + walls weight less than the same volume of air. This is simply not possible with known materials. [Answer] The idea has been around for about 345 years in the form of a [Vacuum Airship](https://en.wikipedia.org/wiki/Vacuum_airship). As the Wikipedia page goes on to say, even a diamond sphere can not be used to hold a volume of vacuum large enough to displace its own mass in air. **However**, [this patent](http://www.google.com/patents/US20070001053), claims it is possible with a honeycomb material for the spherical shell. But if that's true, one wonders why we haven't seen any vacuum airships flying around. But, it's likely due to the possible violent implosion of the spheres. ![enter image description here](https://i.stack.imgur.com/sYBJ7.png) Perhaps when we [run out of helium](http://phys.org/news/2013-04-probing-helium.html), this will be further investigated and we'll start getting vacuum dirigible drones delivering Amazon packages (not blimps, as Burki pointed out, as the shell will necessarily be rigid). [Answer] I've been considering the possibility of carbon nanospheres. If they are formed in a vacuum, they'd *contain* vacuum. They'd have to be fairly large (I'm not mathematician enough to calculate *how* large), but if they were large enough and didn't collapse, they'd be lighter than an equivalent volume of air or even hydrogen. However I'm not sure if they'd be strong enough to withstand air pressure, though carbon compounds are pretty strong. *If* carbon nanospheres are strong enough to withstand atmospheric pressure, then you'd basically fill a container with a whole lot of them, and presto! It floats. The advantage of nanospheres is that if your container is damaged, you might lose some of your nanospheres, but you are unlikely to lose all of them. The nanospheres may even stay in a compromised container if they are large enough and the holes in the container are small enough, so such a system would be damage tolerant, to the degree that you wouldn't have a near-instant loss of lift. ]
[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/4551/edit). Closed 9 years ago. [Improve this question](/posts/4551/edit) My planet's features, such as mountains, plains, and rivers were formed because the Tolks, people with superhero-like qualities, used it as a battlefield. They have offensive and defensive abilities like teleporting, long-range elimination, and disabling the opponent. Later, it became inhabited by Grundasians (the natives, which are unsophisticated like humans). It takes a long time for superheroes in movies to defeat each other, compared to humans. I don't want the war to take up most of my timeline. If my Tolks were organized in armies against each other, would the war last a long time compared to a battle between my natives? [Answer] I'll try the no answer as it's a bit of a pet peeve...unless the superpower is 'indestructible', battles between superhumans would be insanely quick. Most superhumans are granted powers that greatly enhance their offensive capabilities, but rarely come with defensive benefits beyond the physical endurance of an extremely fit human. If you can leap over a building in a single bound, what exactly prevents you from going splat on the other side? Movies (and comics for that matter) have a poor effect on this, that is well illustrated by the Mike Myers 'Austin Powers' series. In particular, Dr.Evil and Scotty Evil debating what to do with a captured Agent Powers. Scotty is the realistic one with his "let's shoot him!" approach, but 'Scotty, no' comes up and Dr.Evil insists on a elaborate plan to kill Austin Powers, all overseen by one inept guard. Most movies depend on this... a superhero can only be overcome by a supervillain after all, and a common trait among all supervillains is the conceited need to gloat over a captured opponent instead of finishing them off, revealing the extent of their evil plan and forcing the hero to watch (and letting the hero survive and escape to foil them in the end). In a war situation, this need to gloat isn't shared by either side, and the 'finish them' mentality would be far more frequent. The Transformers series can also be used here. In a series you start and end the episode in the exact manner it started (Simpsons Paradigm). No matter how badly beaten or close to destruction a Transformer is, in the series, they are back up and ready for battle in the next episode. The (ever so slightly) more realistic movies show these Transformers drop like flies as, there *is* no 'next episode' I like the recent 'Flash' series component, in that he can run exceedingly quickly, but it still expends the energy of normal running and he is forced to consume massive amounts of food to keep himself going. War brings shortages, including food. If your superhumans consumed more resources on a day to day basis, then there would be added incentive to both sides to see a short war and not a protracted one. Teleporting is also an interesting power to have here. Much of the long timeframe components in war is troop movement. Teleporting eliminates that. So... my answer is **No**. Movies are horribly incorrect. When you massively increase someone's offensive capabilities without a corresponding defensive increase, the battles will be significantly quicker. Riskier moves will be taken, the destruction will reach an absurd level, and it would be over in a heartbeat compared to our modern conflicts. [Answer] The reason why wars take as long as they do is mostly because of transportation and reconnaissance. The average soldier in the average war spends magnitude more time to travel to the battlefield and find the enemy than they spend actually engaged in combat. For millennia, soldiers going to war traveled for months until they got to the enemy. The battle itself only took hours. In the modern age where aircraft and motorization allow soldiers to get to the site of operation a lot quicker, the most time-consuming part of war is finding the enemy. Most modern wars are asymmetric. The side with the inferior position goes into hiding and uses guerrilla tactics so the superior side can not use their numerical advantage to overwhelm them. Instead, they need to patrol the whole theater searching for the enemy which is a very tedious and time-consuming activity (Vietnam war, Afghanistan-Soviet war, Chechen wars, Afghanistan-US war, to just name a few examples). These conflicts would end a lot quicker when it would be possible to easily detect the enemy locations so they can be engaged directly. So when you **give your Tolks not just the ability to travel quickly through teleportation but also the ability to detect their opponents easily** over long distances, they can spend most of their time in direct combat which will end the war rather quickly. This is simple math. When we grossly oversimplify the combat and assume that all combats are one-on-one duels to the death and each duel takes an hour (longer than the average showdown in the average superhero movie), the population will halve every hour. When we assume a population of 10 billion, **it will take just 30 hours** until there is just one survivor (logarithm to the base 2 of 10 billion). Even when you improve their defensive capabilities and endurance so that it takes a whole day of epic combat until one of them is killed, it would take merely a month until the conflict is over. [Answer] **Yes, to a point**. It would last longer, I couldn't begin to say how much longer though. If we look at progression in weapons, wars got longer and longer between equal powers while battles, if anything, got shorter. WWI was a big long affair because of trench warfare and that has to do with high firepower, relatively low mobility, and an imperfect mix of ranges as far as I understand it. Similarily long, The Cold War and likely any other WMD War to follow are long protracted affairs but are a little less "warlike". So you probably will hit a cliff at the WMD level where things happen instantly if allowed. Much more likely though is agreements banning such weapons and a cycle back into longer warfare styles. With superhumans you can't just ban things though, so **if their power levels get to WMD** then its up to the individual if they use it and level the playing field and **wars do get shorter.** [Answer] The duration of a war is very hard to predict, but essentially comes down to a combination of factors: * Does technology (or super powers) favor defense over offense? * Are the sides cautious or aggressive? * The goals of the antagonists (for example if one side just wants to wipe out the other they will deploy much more devastating weapons than if they want to claim the other side's resources). * First strike advantage. * Mutually Assured Destruction. So if you have two sides with cautious leaders and strong defenses you may never see open war and things can drag on for a very long time. Likewise Mutually Assured Destruction can lead to a standoff, often with a Cold War or Proxy War. On the other hand if offensive powers tend to win and the person who attacks first has an advantage and the two sides see no way to end this other than the death of all the others then both sides will tend to throw everyone at each other as fast as possible and the main war could burn out in as little as a few hours. [Answer] I'd say such war would end rather quickly. The closest thing we have to superheroes in the real world are special ops units, and their entire training is focused on one thing: bring the other guy down VERY fast. When you see some competition between such guys you'll notice that they don't fuss around like in the movies - the fight takes seconds and ends the moment one guy gets the upper hand. I suppose the battles between superheroes would be similar - they struggle for a couple of seconds, and then one guy is toast. The only problem are those with teleportation, super-endurance, or ability to become incorporeal. They either will be deciding factor in each battle, or there will be some good counter-superpowers (like superspeed for telerporters, psychics for indestructibles, a good vacuum-cleaner for ghosts, etc). ]
[Question] [ * They do not have access to fast and reliable transport options like steam boats, trains and do not use fossil fuel. They can only rely on the power of the winds and water currents for long distance travel. And they could also do it on land of course. * Countries can import food but it's much more limited than it is today. Conservation techniques are not as good so you can't trade fruits over long distance for example. Unless they are dried or processed in some way that they can be kept for a moderately long period of time but I don't think it can be a good substitute for normal food. I'm making the assumption that importing food comes with some risks. The weather can be unpredictable, it is risky also because of war. More broadly, it makes you more vulnerable to others if you depend on imported food. It's still a problem today with food but with other resources as well. **How much of the country consumed food can come solely from importation ?** 10%, 20%, 30% ... The imported food can come form another country or another region inside the same country that is far away. Like the Romans importing food from Egypt. [Answer] **This is practically impossible to quantify** to 10%, 20% as you write in your question, because even if we had statistics, which we don't, what would be the basis for measurement? Also, you don't specify what you mean exactly by "pre-modern". Also, coming at **the question as "How much of the country consumed food can come solely from importation?" is not going to have one answer**. Even if you could quantify it (say in an abstract simulation or game) it is going to vary a lot by the specific situation. For example, the amount of trade that other places can and will send has little or nothing to do with the population living someplace, other than what they have of value to trade with, and how much food is available domestically - they are all independent variables, and the relationships between them are complex and non-deterministic. However, I think it's fairly safe to say that before large-scale trade, **every people needed to at first get, or be *able* to get, 100% of its food from its own surroundings**. Food that they would want to trade for from someone arriving in a ship would tend to only be things that they did not have, or did not have the same type and quality. Food and ingredients were traded even by the first traders, however, particularly because some things were scarce or not available at all in the market location, so **the percentage consumed *of a particular good* could be very high or even 100% from trade**, unless and until that trade actually allowed the recipients to produce it themselves (via copying, or via seeds or fertile animals, for example), depending on what it was and what the local conditions were. For example, the "Western World" still imports coffee from the few places where it can be grown. [Answer] Grains store pretty well (well, considering your other options) - on the order of 20+ years. And can be shipped. Many countries shipped out all of their wheat production in the Middle Ages. And shipped in a *lot* of meat, for Christian 'meatless' days, which drove a lot of shipbuilding and fish-catching - as well as fish-drying. Most countries didn't get to 100% sustainable, because they never needed to. And when trade was cut off, or crops failed - large swaths of the population died or migrated. That's why one of [the four horsemen talked about in the Christian Bible](https://en.wikipedia.org/wiki/Four_Horsemen_of_the_Apocalypse) is famine. A routine part of life back in the day. Fruits are not the basis of anybody's diet. Probably of more interest is going to be protein and fat trading. Read: dead animals. Most people, in most of the past, have lived mostly on grains; typically one of the big 3: wheat, rice or corn. All of which ship well. Very few people (royalty/rich), since the advent or agriculture, have had varied diets. The other answer is correct: define pre-modern; and hard numbers (or even guesses) are going to be hard to come by. If you want some Middle Ages reading, go to Braudel. If you want an example of modernity, look to Nauru - who were going on 100%, mainly because they were rich enough to do so. If your country is rich enough, you can get lots of things done... but the problem with that is the same thing that happened in Spain after the new world gold/silver influx happened - nobody wants to do any work. And that's unsustainable in the long-term. [Answer] As the question says, it is impossible to have a hard and fast answer. However, here are a few factors to consider: * **Production capacity and population.** A city-state without any farmland of its own might be almost totally dependent on food imports. An example would be early medieval Venice, which could catch its own fish from the sea but otherwise imported practically all of its food. On the other hand, medieval England was more or less self-sufficient in food, so it only imported luxury items. * **Transportation and storage.** Without modern refrigeration, things like grain, hard cheeses, preserved meat and fish, wine, or olive oil can still be transported long distances. Fresh vegetables, meat and milk are impossible to store for more than a day or so. If you want to move fresh meat long distances, it is much better to transport the live animals and slaughter them at your destination. Moving goods by water (canals, rivers, seas) is generally much faster and easier than by land. * **Wealth and organization**. Moving large quantites of food long distances implies a well-organized government like ancient Rome. Impoverished societies may be unable to pay for food from their wealthy neighbours, even if the food is available -- see the Irish potato famine for a historical example. * **Political considerations.** Because of political, military, or cultural factors, a country might choose to import food from a more distant location instead of nearby. [Answer] The answer to the question is that a pre-industrial country can import all of its food. The ability to **import** food is not meaningfully limited by technology. It is just a matter of building and maintaining the infrastructure. You need functional sailing ships, good harbours, and good roads. Granaries and ceramics too, but those usually precede the technologies I mentioned before. However the ability of pre-industrial societies to **export** food was seriously limited. Only the most fertile areas would have had significant excess food to export. And only for the most efficient food sources, mostly only some cereals and potato had yields high enough to create exportable levels of food. Additionally in pre-industrial era seas had **much** more fish, allowing fish to be exportable source of protein. Another large difference the level of technology makes is that before industrialization high levels of agricultural production were **not sustainable**. Soil quality would be continuously dropping due to intensive agriculture and irrigation. Chopping the timber and wood required for the ships and other infrastructure would cause deforestation and severe erosion. The fragile balance of production of consumption would have been vulnerable to disturbances caused by epidemics, which would quickly spread along busy trade routes to the densely populated cities. So the real limiting factors would have been access to rich agricultural areas with surplus food production and the time you have before your natural resources become depleted. In addition, there are issues with economic balance that should be considered in scenarios where an area imports large portion of its food. That food needs to be paid somehow, even if its just not having taxes to spend on something else. [Answer] The question is based on a misconception: > > *I'm making the assumption that importing food comes with some risks. The weather can be unpredictable, it is risky also because of war. More broadly, it makes you more vulnerable to others if you depend on imported food. It's still a problem today with food but with other resources as well.* > > > For a small or medium-sized country relying on domestically-grown food exclusively is *more risky* than relying on a healthy mixture of local and imported food. The reason is the lack of *diversification*. *Local* weather can be unpredictable; there can be a drought covering most of a small or medium-sized country. *Local* animals can succumb to a contagious disease. *One* province can fall into civil unrest. But for the entire *world* (or at least for an economy-world in the sense of [Fernard Braudel](https://en.wikipedia.org/wiki/Fernand_Braudel)) this is much less likely. A country can import food from wherever it is available; if no food is available in the entire economy-world then it means that the civilization is at an end anyway... A large country, such as modern U.S.A. or the ancient Roman Empire is an economy-world in itself; such a large country *may* choose to forego imported food, because it is large enough to find sufficient diversification domestically. Basically, putting all your eggs in one basket is risky. Sourcing your eggs from all over the world is much safer. ## But what about pre-modern? For a pre-modern country (meaning a country which does not yet have efficient overland transportation) the fundamental limitation is that before the advent of pervasive canal and rail networks transporting food overland was prohibitively expensive and, really, impossible for large quantities. Most food *had* to be grown locally, simply because there was no way to carry it overland. In the ancient world, cities such as Rome (with its own dedicated port at Ostia) or Constantinople could rely on imported food brought by ships. But an inland city such as Cologne or Turin had to source their food from nearby farms. [Answer] It depends on your definition of "pre-modern". * **Romans importing food from Egypt was during 'Pax Romana'** where advanced trading routes connected all parts of the Roman Empire. Free people were better fed than slaves. All that fell apart at Dark Ages. * During **Dark Ages most people lived in their village,** never left, and consumed food they themselves grown in close area. Only addition to local diet would be salt and few (expensive) spices. Nobility lived better, but was minority. pre-modern is big place. [Answer] If you want to have a state which relies exclusievely/mostly on import for food, you have to consider how that state came to exist at all. Let's review a few points that are worth considering. # History You have to consider how come a state that is strongly dependent on trade for basic resources like food came into existence and, maybe more importantly, kept independent, at least to the point of the story. Different reasons can be seen to explain that. In particular, * it is a vassal country. It is independent in name only. In reality, it could be seen as an autonomous state within a larger one. The city-states of the Holy Roman Empire could be a good illustration. * it is a new country. A gold mine was discovered and the first inhabitants are fully dedicated to the new trade and have basically no time for farming. Furthermore, the commerce flourishes and they can import a sizeable portion of the consumed food. But as the time grows, farming around the mines will be done to feed the population and increase the benefits. * it is a trade hub. It is very well situated on the roads of the international exchange of goods, and as the business got strong, they can actually buy the products transiting through it. I'll come back to those later. # Environment Unless the state is limited to a city (and even then), some ways of producing food always existed. Consider the following cases. * It's a small island? For sure there are some fishes around. * It's in the middle of the mountains? Goats, sheeps, or cows could graze on the mountains sides. * It's in the middle of a large desert, then the Oasis will allow to get some fruits, vegetables, and feed a few goats for the milk and some meat. Or you might travel around with small herds to get to the best grass plains (Mongolia). Without any other factors, those lands would harbor only a few people living there. Import is expensive, and you need to pay for it. How, if you have only few resources. And you also need a reason to import: your population is larger than what the land can sustain. So generally, you never get to 100% imported food, for the simple reason that you can always produce something locally. And it is cheaper. # Diet Consider a state which has some small resources. Then, for some historical, economic, political reasons the population start to grow. The state develop strongly its trade capacities. People get richer, and more people migrate to it, and those living there have more healthy children. Slowly the food resources of the country would not suffice for the increasing population. As trade is a major point of the (now, relatively rich) state, they import it. Anyway a lot of food already transit through the state, it is pretty simple to actually buy it. As some other pointed out, the problem is that to be able to import, you need that other countries are willing to export. That either mean, very expensive or that the other countries have a surplus. Salted-Meat could be transported of ships for some months (think about transatlantic trade, or whaling), but the population of the 17th Century had often a meat-free diet. > > the poor [...] subsisted on food like bread, cheese and onions. Ordinary people also ate pottage each day. This was a kind of stew. It was made by boiling grain in water to make a kind of porridge. You added vegetables and (if you could afford it) pieces of meat or fish. > > > -- [[Source](http://www.localhistories.org/stuart.html)] > > > As other answers state it, the grains could travel for quite some time, to make it a reasonable imported good. # Illustrating examples History provides a few examples of trade centers with a high importation system. In a few minutes search on the web, I couldn't find any precise values, but you might consider the following illustrations * [Venice](https://en.wikipedia.org/wiki/Economic_history_of_Venice). It was already mentioned in another answer, but Venice started relatively small and grew to be a major trade centre. It is worth noting that in the 6th Century, > > Fishing is the means of livelihood, salt the industry > > > -- [[source](http://www.sjsu.edu/faculty/watkins/venice.htm)] > > > As they became [richer](http://www.theworldeconomy.org/impact/The_Venetian_Republic.html), Venice acquired more land. So probably the net import from other countries wasn't so high. But imports from mainland, or Dalmatian territories was probably high to feed the 170,000 inhabitants of Venice. * [Kingdom of Jerusalem](https://en.wikipedia.org/wiki/Kingdom_of_Jerusalem#Economy). Was a Kingdom built by the conquest from the Crusades. It was established in the 11th Century and ruled by Europeans. The agriculture of the land was quite limited, and they relied heavily on imports. It was a very important [trade cross-road](http://www.essaytown.com/paper/economics-kingdom-jerusalem-economy-kingdom-37985), but they nevertheless depended on financial support from Europe. As a consequence, > > the kingdom was not wealthy, depending on trade with the Muslims, banking activities, and taxes on pilgrims to keep the government operating and to provide for defense. Though there were some fertile districts, much was barren, and in bad years grain had to be imported from Syria to feed the Christians. > > > -- [[source](https://www.britannica.com/place/kingdom-of-Jerusalem)] > > > Which probably explain why it was relatively short-lived. * First colonies on the American Continent. They were not self-sufficient, and the imports were very hazardous (time and risks). That explains why the first colonies, and in particular in North America were struggling. When they develop their self-subsistance, they fared progressively better. # Conclusions I am not very original, but I would conclude like most of the others. It would be hard to quantify the amount of food import that a country might tolerate. But I hope I managed to give you an idea of the several factors you would need to consider when building your state. And on the top of the transportation risk, you add political risk of dependence. And that is often avoided (if possible) by any state. [Answer] For staples you don't want to import any of your food because of the risks you mentioned, for luxuries it depends on how much you produce and how much you're willing to spend to get more. If you produce no luxury foods then obviously 100% of your luxuries are imported even if that is zero pounds of food per year and your whole country survives on staple grains etc... If you have the national treasury for it and you don't produce any food at home then anything up to and including 100% of your country's calorific needs can be supplied by foreign trade, it has happened in living memory, several African states have in the past few decades grown exclusively cash crops for a season or two while under pressure to repay international loans and bought in their daily bread but it's not a good position to be in, especially when your cash crops fail. Edit: I should add that that is *if* you have neighbours willing to trade, otherwise you have no show, and of course if they do trade and then their harvests are bad and you're reliant on them then you're in a lot of trouble. [Answer] Some detailed information about Rome's grain imports: <https://en.wikipedia.org/wiki/Cura_Annonae> I understand a full 33% came from Egypt during the early Empire. <https://www.jstor.org/stable/4238709> ]
[Question] [ I was rewatching Secret war from Love, Death & Robots and started wondering, would the monsters from that episode pose any actual threat in today's world? Let's assume the monsters have similar characteristic as the ones in LDR. * No special magical abilities * Faster and stronger than humans * Live and breed underground, but hunt on the surface * Live in hive like structures. When a hive reaches a certain size it sends out colonizing workers which try to establish a new hive 10 to 100 km away from its original location. The new hive operates as individual entity independent from original hive. * Mostly nocturnal, but can operate in daylight if forced * There are several variants of the monsters, where smaller ones develop and mature faster than bigger ones. * Hunt and kill any animal including humans that comes their way * Posses enough intelligence to successfully hunt in packs. For this scenario it is irrelevant if monsters came to Earth through a failed magical ritual or are part of a failed cloning experiment. They exist and until they reach high numbers almost nobody is aware they exist. People become aware of the monsters when they start appearing and hunting in big cities. Lets put first big hives in the Amazon rainforest in Brasil. First sightings and mass killings happen in Brasils state Para and Mato grosso. How would government and military react to this threat. How fast should monster be able to multiply and expand in order to avoid extermination. Edit: Added some more specific information. [Answer] # We're humans. We're a walking, talking, ecological disaster The equivalent of the dinosaur killer comet on legs. Responsible for the death of 70% of land mammals in the last 50 years. We used to hunt the closest thing we have to a multi tonne, ship crushing, kracken eating sea monster for its oil, which burned nicely, and we only stopped *because there were virtually none left*. The point I'm trying to make is, that if there's one thing our civilization has figured out, it's how to wipe out a species. First up, I'd argue these won't go unnoticed until they get to cities. Even if they only hunt sheep and not humans, we have this nasty habit of carrying cameras everywhere, and farmers tend to notice sheep vanishing. We're talking 1000 of these things, tops, before someone spots one and starts to take notice. If they hunt everything, we'd set up decoys, or poisoned or booby trapped baits. Animal traps. A few sheep in a field, and a bunch of hunters. If they sleep underground, we'd fill their lair with gas. Do they need to breathe? If not, that's fine. We've got nerve gases that are absorbed on skin contact. A major surge in these would result in a local city lockdown. Snipers would be deployed, we could track the creatures with thermal cameras on helicopters or drones, meaning very little chance of them ambushing us. When they retreat, because pack animals are smart enough to do so, we'd trace them back to their lair, and set it on fire. Or, y'know, gas again, because we're in a city and want to skip out on property damage. If it turns out they breed too fast, we'll switch to biological warfare - a non earth creature is likely to be pretty safe to target with some home brewed viruses - the odds of us infecting our own population would be small. In the meantime, we'd keep their numbers down by poisoning, trapping, and shooting them. I predict we'd be absolutely fine. Unless they're an [emu](http://veritablehokum.com/comic/the-emu-war/) [Answer] If these monsters were to exist in the real world, the government and military would likely take a multi-faceted approach to dealing with the threat. Initially, they would probably focus on containment, setting up quarantine zones and using military forces to secure the perimeter and prevent the monsters from spreading to other areas. They may also use air and ground forces to try and locate and destroy the hives. As the situation evolves and more is learned about the monsters, the government may decide to launch a full-scale military operation to eradicate the threat. This would likely involve the use of heavy weapons, such as bombs and missiles, to destroy the hives and kill the monsters. The speed at which the monsters can multiply and expand would be a critical factor in determining the success of the government's response. If they are able to reproduce and spread quickly, it may become very difficult to eradicate them, and they could pose a significant threat to the population. On the other hand, if the monsters are slow to reproduce and spread, the government may be able to contain and eradicate the threat before it becomes a major problem. I think that the only way for them to survive is to reproduce so quickly that it would look like mitosis, where 1 becomes 2 and 2 becomes 4 and so on ... we would reach massive numbers in months and wouldn't be able to contain them... But if the reproduction rate is like us (humans), then they wouldn't be able to reproduce quickly enough to not be noticed, since humans may have only 1 child per year ( or in twin cases a little bit more ). ]
[Question] [ I'm thinking of an energy source where you could put organic life forms in and get out energy that could power something (edit: something that can be transported in a small space; where you can put plants in and get energy/electrons out anode and cathode, produces very little heat and last a long time). I'll answer questions if you have any. [Answer] # Fermentation Heat: Fermentation generates heat. The bigger the fermentation system, the more heat that you get out of it. In fact, soon fermentation systems will be so big that [getting rid of the heat](https://go.gale.com/ps/i.do?p=AONE&u=googlescholar&id=GALE%7CA349227737&v=2.1&it=r&sid=AONE&asid=605cc773) will be a major problem. But if you're looking to capture energy, heat is your friend. While it isn't as powerful or sexy as fire, you can get [electricity from a heat gradient](https://en.wikipedia.org/wiki/Thermoelectric_generator#:%7E:text=Thermoelectric%20materials%20generate%20power%20directly,to%20be%20good%20thermoelectric%20materials.) using thermoelectric generators. # Horsepower: The oldest way to get power from biomass. Feed it to an animal. Make the animal do work. Turn a wheel, and you can turn a generator. You may even be able to use your waste material from your fermentation system as feed for the animals to improve the efficiency of a combined system. [Answer] **Microbial fuel cell?** <https://en.wikipedia.org/wiki/Microbial_fuel_cell> > > Microbial fuel cell (MFC) is a type of bioelectrochemical fuel cell > system[1] that generates electric current by diverting electrons > produced from the microbial oxidation of reduced compounds (also known > as fuel or electron donor) on the anode to oxidized compounds such as > oxygen (also known as oxidizing agent or electron acceptor) on the > cathode through an external electrical circuit. MFCs can be grouped > into two general categories: mediated and unmediated. The first MFCs, > demonstrated in the early 20th century, used a mediator: a chemical > that transfers electrons from the bacteria in the cell to the anode. > Unmediated MFCs emerged in the 1970s; in this type of MFC the bacteria > typically have electrochemically active redox proteins such as > cytochromes on their outer membrane that can transfer electrons > directly to the anode.[2][3] In the 21st century MFCs have started to > find commercial use in wastewater treatment > > > The microbes are alive and they can generate your lunch electricity for you. They do not burn. But here is the no such thing: a free lunch. Live things (heterotrophs like myself and the cat) need to eat something or (autotrophs like this vine which might be poison ivy) fix outside energy like sunlight. If an organism cannot take in the energy it needs, it starves and dies. If you use a live microbial fuel cell you need to feed these microbes, ideally something you have but do not want, like poop. If you have a life form generating your electricity you need to give that life form food or energy that they can use, both to sustain themselves and to make the electricity. [Answer] Yes, it could be possible to modify some plants so that you could take a small part of their energy harvesting process to generate fuels. For example, some fungi are able to tap into the plant process to get the energy they need. However, the resulting energy will be small. Part of this is that you don't want to deprive the plant of resources it needs to keep growing. Another part is that plants are not all that efficient in capturing sunlight energy. More energy can be gotten by growing perennial plants and harvesting the flowers, seeds, and stalks and converting them into energy. Even more energy can be gotten by using more efficient solar collectors. [Answer] **A 2,308 V lemon battery.** [![enter image description here](https://i.stack.imgur.com/7w6E2.jpg)](https://i.stack.imgur.com/7w6E2.jpg) The RSC team used 2,923 lemons to generate an astonishing 2,307.8 volts, which smashed the previous world record of 1,521 volts, and subsequently launching a battery-powered go-kart race run by the Blair Project in Manchester. Source: [Bath.ac.uk](https://www.bath.ac.uk/announcements/lemons-aid-juicy-guinness-world-records-breaker-for-highest-voltage-fruit-battery/#:%7E:text=The%20RSC%20team%20used%202%2C923,the%20Blair%20Project%20in%20Manchester.). ]
[Question] [ A group of ~100 people working together have built a large forest secluded from the rest of society. The [forest](https://worldbuilding.stackexchange.com/questions/220542/will-nature-after-millennia-create-a-temperate-rain-forest-in-my-structure) is ~70 km by ~70 km square. It has no seasons and can not be [found or accessed](https://worldbuilding.stackexchange.com/questions/214583/a-perfect-filter-spell-what-knowledge-could-it-bring) by any other than those ~100 people. The group consists of mostly merchants trading throughout the country and getting rich in the process. Trading for food is usually much more convenient than gathering it themselves. But in times of famine or persecution they want to be able to switch to getting food from their secluded land keeping their lavish diet as much as possible. How would one prepare this land with **minimal** amount of effort so that plenty can be harvested at a time of need? The technology available would be roughly 1200 medieval England. Magic is present in the world. It has created the secluded forest. But it is often unavailable to the group for long periods. So it is not that useful as an emergency feature. edit: The whole group can and would work to harvest the food when there is a need for it. It is only in normal times that they have little time to tend to their land. [Answer] **Temperate plants in tropical climate** Many plants only make the edible parts once per year in the Summer. Trick your plants into thinking it is always Summer, by planting them in a place warmer than where they evolved. **Edit:** Some plants decide when to make fruit based on the number of hours of daylight, and not just the temperature. This is a different problem with the same solution. Plant temperate crops that fruit in summer when there are 12 hours of daylight; and build your garden on the equator where there is always 12 hours of light. Or set your whole story on the equator to avoid this problem entirely. > > The forest is ~70 km by ~70 km square. It has no seasons and. . . > > > Well that makes it even easier. If there are no seasons ([we're allowed to have one](https://www.youtube.com/watch?v=OwHGE7uhjco)) by some spell then simply make the spell so the single season mimics the temperature and hours of daylight of the fruiting season for whatever you plant in the garden. **Tubers** [![potatoes](https://i.stack.imgur.com/Hj7ET.jpg)](https://i.stack.imgur.com/Hj7ET.jpg) Carrots, Potatoes, Parsnip, Yams, Taro are all tubers. The plant uses them to store nutrients for the Winter. If your garden is tropical they will never need to use the tubers, and they remain in the ground ready for use at a moment's notice. **Beehives** [![enter image description here](https://i.stack.imgur.com/jBpDB.jpg)](https://i.stack.imgur.com/jBpDB.jpg) The bees do not need to be supervised. They feed themselves from the potato flowers. You can come back at a moments notice and harvest the honey. **Orchards** [![enter image description here](https://i.stack.imgur.com/w1QwJ.jpg)](https://i.stack.imgur.com/w1QwJ.jpg) Your garden is full of temperate fruit trees. Those guys only fruit in the Summer. But since the forest is tropical they think it is always summer. They always have fruit. **(Some) Spices** Some spices are leaves or bark or roots. Herbs, Curry leaves, cinnamon, ginger and turmeric are available all year around. Others are seeds or flowers. Some temperate ones might be available as with the orchards. [Answer] Fruit and nut bearing trees require the least amount of effort to provide food, and having a rich variety of food-bearing trees would possibly provide them with enough food to live on, but it would not provide them with anything close to a "lavish diet" unless they consider fruits and nuts a lavish diet. They could, however, have trees that don't exist on Earth, trees which produced fruit/nuts exceptionally rich in variety year round. Meat is labor intensive, but a deep stream/lake stocked with a variety of fish is doable with less effort than keeping meat animals. Barring circumstances non-existent on Earth, I can't think (based on experience) of a non-labor intensive way to provide oneself with a varied and a-bit-close-to-lavish diet. One summer, my family survived on only what we could grow ourselves with the exception of flour, sugar, and another basic that I can no longer remember. We had milk goats (and male kids), chickens, ducks, venison, and other birds as sources of milk, cream, meat and eggs, and a large garden with a lot of different veggies. Our land had a lot of briars, so we had plenty of 2 kinds of raspberries and one variety of blackberries, all wild. In addition, I had small fruit-bearing shrubs. While we ate pretty well (I made our cheeses, pasta, and sausages), and my kids helped a lot, I'll tell you that *I have never worked so hard in my life as I did that summer, and never will again!* Feeding oneself even moderately well is a **lot** of work! [Answer] American chestnut tree American chestnut trees could produce 100lbs of food per tree per year once mature. Chestnuts are both edible by humans and provides a massive food source for wild game, wild game being a much more reliable food source. Harvesting was often does with a simple shovel since the seeds were so abundant and hardy. They trees are large and provide a large open space underneath them perfect for camping as well. As a bonus they also produce rot resistant wood. They are virtually extinct today but this only happened in the last hundred years due to imported diseases. Preparing the land could not be easier clear away existing trees and plant some chestnut trees, they are competitive on their own but with a head start they will quickly establish themselves. They might not even have to clear he land, when native Americans brought chestnuts to Pennsylvania it only took the trees a few hundred years to become dominate, making up 25-30% of all hardwood trees in the state. [![enter image description here](https://i.stack.imgur.com/EipdT.png)](https://i.stack.imgur.com/EipdT.png) [![enter image description here](https://i.stack.imgur.com/glwjL.png)](https://i.stack.imgur.com/glwjL.png) [Answer] Semi wild herd animals. In times of plenty the herds grow and the animals get fat, in time of need you thin the herds and eat the animals. [Answer] There could be choices depending on the situation, water supply, effort, climate etc. **Fruits** If the food is just fruits, trees can be grown in a fertile area with enough water supply. * Some fruits are used when they are ripe e.g. apples, mangoes, oranges etc. * Some fruits can be dried and used later on e.g. figs, apricots. * Seeds of some fruits are used which can be stored and consumed when needed e.g. almonds, pistachios, pine nuts, cashews. *Pros* : * Very little effort is needed. * Bees can make hives on trees to produce honey. * Birds can make nests on the trees. * No cooking needed. *Cons:* * Food has little variety. * Food is deficient in many nutrients. * This is only an emergency measure used for little time. * Most people will be fed up if used for long time. **Grains** If the food is grains e.g. rice, wheat, millet, barley, corn, then you need to * plough the land so you need bulls or horses. * irrigate the land at necessary intervals. * cut the harvest. * separate the grains from husk using plank pulled by horse or bull. *Pros* : * Grains can be stored for long time and available whenever needed. * Animals will also be available for milk, meat, eggs etc. * A large variety of food is available. * People will get all kinds of nutrients needed. *Cons:* * A lot of effort is needed. * Cooking is needed. **Vegetables** If the food is vegetables e.g. potatoes, turnips, spinach, carrots, cauliflower, then you need to * plough the land so you need bulls or horses. * irrigate the land at necessary intervals. * cut the harvest. *Pros* : * A large variety of food is available. * People will get many kinds of nutrients needed. *Cons:* * A lot of effort is needed. * Cooking is needed. ]
[Question] [ This is for the video game I'm developing called [Skullborn](https://www.skullborn.net/). In this game there are large crystals that have energy that the player can harness. Claiming a crystal is essentially how the player claims territory (of the area surrounding the crystal). The energy of the crystal protects the players land as well as powers furnaces for smelting ores and more. However the player must add energy to the crystal in order to keep it claimed as theirs. (If you have ever played Rust it's similar to a Tool Cupboard) Players can get energy by defeating elemental creatures but I want to add a farming mechanic that also allows players to give their crystal energy. So that the player can log in every day and farm a bit to keep their crystal claimed. I'm not sure how this should work though. The only thing I can think of is that there is something like the [Bio Mass burner from Satisfactory](https://satisfactory.fandom.com/wiki/Biomass_Burner#:%7E:text=The%20Biomass%20Burner%20is%20a,Biofuel%20for%20higher%20fuel%20efficiency.) but I don't love that solution because it seems kinda dumb/wasteful/and doesn't fit the theme of the game. Here is the rough idea I have for the lore/story if you are curious: > > There were magical goblins with elemental powers. Then aliens invaded > with technology and weapons powered by crystals. There was a huge war > in between them. Then the aliens dropped a nuclear crystal on the > goblins elder tree (the source of their powers). Which caused a huge > explosion. The explosion scattered crystal shards all over the world > that were imbued with the chaotic elemental energy of the elder tree. The explosion also > disintegrated the flesh off of everyone's bodies, leaving nothing but > the skeletons and their souls were left to wander the earth searching > for a body to call home again. > > > One major thing to note is that there is "technology" but it's very mystical/magical and all powered by the crystals. So visually think of the technology from [Breath of the Wild](https://www.google.com/search?q=breath%20of%20the%20wild%20motorcycle&tbm=isch&ved=2ahUKEwjI6o_eot33AhUgqWoFHXgFBQIQ2-cCegQIABAA&oq=breath%20of%20the%20wild%20moto&gs_lcp=CgNpbWcQARgAMgQIIxAnMgUIABCABDIFCAAQgAQyBggAEAUQHjIGCAAQBRAeMgYIABAFEB4yBggAEAgQHjIGCAAQCBAeMgQIABAeMgYIABAFEB46CAgAEIAEELEDUPMKWLsOYPoUaABwAHgAgAE2iAHuAZIBATWYAQCgAQGqAQtnd3Mtd2l6LWltZ8ABAQ&sclient=img&ei=nbl-YoioIKDSqtsP-IqUEA&bih=763&biw=1536&rlz=1C1ONGR_enUS933US933#imgrc=n6hUIahBnHL-uM) or the [Dranei from World of Warcraft](https://www.google.com/search?q=draenei%20ships&rlz=1C1ONGR_enUS933US933&sxsrf=ALiCzsYhR-6_FG-gmA-3TAaSdEK9Jb-B6A:1652472281786&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjxlu36ot33AhVvomoFHdahBAgQ_AUoAXoECAEQAw&biw=1536&bih=763&dpr=1.25) or the [Protoss from Star Craft](https://www.google.com/search?q=protoss%20buildings&tbm=isch&ved=2ahUKEwi70cCLo933AhWGnGoFHblyAxIQ2-cCegQIABAA&oq=protoss%20buildings&gs_lcp=CgNpbWcQAzIFCAAQgAQyBggAEAUQHjIGCAAQBRAeMgQIABAYMgQIABAYOgQIIxAnOgQIABBDUOIBWP8LYJoNaABwAHgAgAE4iAGcBJIBAjExmAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=_Ll-YrvjKoa5qtsPueWNkAE&bih=763&biw=1536&rlz=1C1ONGR_enUS933US933) [Answer] # Offerings: Your energy is derived from chaos beings, so it's a hair's breath from magic. So how about agricultural products being an offering to elemental beings? All entropy leads to greater powers of chaos beings. The dissolution or burning of offerings fuels a chaos being that then returns part of the derived power to the crystal. Or the beings that created the crystals feed off of life energy (elemental chaos life being the best), and by offering freshly picked plants (life), the crystals are powered. # Elder Tree Saplings: As for a crop to plant, how about elder tree saplings? The goblins got their power from there, and perhaps obtaining the elder tree energy was the point of the invasion. This does, admittedly, have a sort of "[Invid Flower of Life](https://robotech.fandom.com/wiki/Flower_of_Life)" feel, but that isn't entirely a bad thing. Since the crystal is feeding off of the trees, they will wither and die if not regularly watered, fertilized, and kept free of weeds. The saplings could even be compelled to intertwine their roots to the crystal. This also provides a connection to the crystal "claiming" the land. Perhaps this is what the invading aliens intended to do to the planet all along, gradually creating a network of crystals controlling more and more of the land... [Answer] **[Propolis](https://en.wikipedia.org/wiki/Propolis)**. (AKA. Bee glue.) You say the crystals shattered, and were imbued with the essence of Elder, the element of chaos. They need to be re-balanced. Bees collect nectar and pollen from all the flowering plants, much of agriculture relies on the action of bees to perpetuate crops from season to season through fertilisation. The bigger the farm, the more variety of flowering plants, the greater the number of bees, the more bee-glue. One nifty thing that propolis does, is it dampens harmful vibrations within the hive, preventing structural failure. The greater the variety of plants that contribute their essence to the creation of the bee-glue, the more the elements come back into balance and the chaotic effect of Elder is dampened down. There's a [free-version of Culpepper's Herbal](https://www.academia.edu/35015013/Nicholas_Culpepers_Complete_Herbal_pdf), with much folk-lore about all plant types, magical significance etc.. [Answer] # Dairy Farming [![enter image description here](https://i.stack.imgur.com/S5csK.jpg)](https://i.stack.imgur.com/S5csK.jpg) Your game has the players be skeletons. Skeletons are made of bones. Bones need calcium. Calcium comes from milk which comes from cows. > > I want to add a farming mechanic > > > You want farms in your game. Dairy Farms are the way to go. In fact don't bother with the crystals. Just have a dairy farm. > > Claiming a ~~crystal~~ Dairy Farm is essentially how the player claims territory (of the area surrounding the ~~crystal~~ Dairy Farm). The energy of the ~~crystal~~ Dairy Farm protects the players land. > > > The cows are well trained and weigh nearly a tonne each. They have a bajillion hitpoints and chase off any intruders. This is meant to be silly. Similar to the cucoos in Zelda: [![enter image description here](https://i.stack.imgur.com/ms4dz.gif)](https://i.stack.imgur.com/ms4dz.gif) The cows are not supposed to be killed. So expect this to become a Skullborn speedrun category. If you don't like the idea of aggressive cows, or think it will confuse the players, then instead use an aggressive bull. > > . . . as well as powers furnaces for smelting ores and more. . . . The only thing I can think of is that there is something like the Bio Mass burner. . . > > > Have you ever seen a cow? They are known for their ability to produce copious amounts of ~~faeces~~ fuel. Look here. [![enter image description here](https://i.stack.imgur.com/1uWHB.jpg)](https://i.stack.imgur.com/1uWHB.jpg) Leave these bad boys in the sun for a few days and they dry into a hard pellet to power the furnace. Stack them up to dry faster: [![enter image description here](https://i.stack.imgur.com/iGg7D.jpg)](https://i.stack.imgur.com/iGg7D.jpg) > > player can log in every day and farm a bit to keep their ~~crystal~~ Dairy Farm claimed. > > > The basic daily quest is to collect new cow pats from the ground and arrange them in a heap. You could have a stacking minigame. Kids still like to stack things, right? I know I sure do. Expect a thriving metagame about the optimal way to collect and stack poo. Pick up the pat too soon and it breaks in half and you need to make two trips to the pile. Pats on the outside dry faster. Should the pile be arranged to rotate them? One big pile or several small ones? From there you can make the management as deep as you want. Do you have to milk your own cows? Maybe you can hire someone to do it for you? How much do you pay them? What about cheese making? What about the weather, seasons, breeding, eating all the grass, different types of animals. The list is endless. That sounds amazing. . . . When did you say the game is coming out? [Answer] ## Windmill [![enter image description here](https://i.stack.imgur.com/tKv3M.png)](https://i.stack.imgur.com/tKv3M.png) The farmer could put a windmill and yield electricity, or heat, or mechanical energy, to power up the crystals. ## Biofuels [![enter image description here](https://i.stack.imgur.com/UG0j2.png)](https://i.stack.imgur.com/UG0j2.png) Level 1: sugar and starch To power these crystals, you put the energy in. Your farmer would consider planting starch for biodiesel, or sugar.. when the harvest season comes, the crystals can be powered up. Level 2: algal fuels A farmer could also put tanks on his land to breed algae for algal fuels. These have high yields and can be grown with minimal impact on fresh water resources. But these tanks require extra investment and experience to maintain. Level 3: genetically engineered (best yield, cost max, etc) [Answer] # Tiberium crystals In the CnC Tiberium universe we can see a crystal that has some similarities. A quick talk about Tiberium crystals and what parts you can take from it. A Tiberium crystal is green. It grows quickly by itself, but upon contact with living organisms it tries to mutate them to spread itself further. To grow it pulls resources from it's environment. From organic material to trace metals and other useful stuff. This process has a nuclear effect, making them dangerous over a distance. It is poorly understood why they are nuclear or how they pull materials towards and into themselves. They are a valuable yet dangerous resource, as they can be used for incredible power as well as usable materials. Your crystals are still nuclear, but don't need to be dangerous anymore. It can be powered for long times by sucking materials from the environment, using nuclear energy for efficient energy production. This can be done by offerings to add abundant energy. This energy can be harvested. The crystal might also grow, storing energy in the crystal lattice. That means you can harvest some of this young, newly formed crystal full with energy. To prevent too much power you can have the newer crystal that is harvested not fully realised, making it useful as a battery, but not an infinite resource (yet). This sets up a lot of flexibility for your game. The nuclear power is easily accepted as a long term, powerful energy source. You can add many types and colours to differentiate them. As they pull energy from it's surroundings you can give it energy by just placing stuff near or against it. This can be specific offerings like elemental remains. If you want some crystals can grow. These new crystal parts can still have wildly varying properties, allowing the inhabitants of your world to take parts of the crystals into your world and use them for different effects. [Answer] ## Earth spirit The planet is a magical entity, and its hackles are up because some damn fool detonated a kind of nuclear crystal bomb recently. For its own safety, the Earth spirit has made the natural environment become hostile to the activity of intelligent creatures -- *all* intelligent creatures. The hostility will continue until the Earth spirit is confident that the troublemakers -- whoever they may be -- are gone. These crystals render a zone safe for intelligent creatures by emitting magical energy with the same flavor/signature as the planet's own natural energy, effectively disguising everyone inside the zone such that the Earth spirit thinks the area is inhabited only by the planet's own flora. The obvious, best, and indeed *only* practically accessible source of such energy is the planet's own flora. Of course, no individual plant emits/leaks enough energy to be useful at the scale that's needed, so it must be collected from many plants, and then released in a controlled fashion to provide steady, even coverage. The crystal that secures the zone is both the container and the emitter. Because it is man-made by belligerents in an active conflict, it has been designed to only protect one faction, by blending the flavor/signature of that species' energy with that of the planet's energy. When a different faction seizes a zone, they reconfigure the crystal emitter to match their energy. ### Sources Different plants can have different energy yields. My suggestion would be that plants which evolved earlier in the planet's history should provide more energy per unit time, because the Earth spirit is most familiar with those. This would also dovetail with the extremely common gaming trope that "ancient" stuff is epic while contemporary stuff is low-value. Along the same thinking, any individual plant which is itself very old (e.g. [Methuselah](https://en.wikipedia.org/wiki/Methuselah_(tree))) could also provide more energy, because the Earth spirit has been friends with that individual for a long time. You might do something similar for extremely old *intelligent creatures*, particularly mystics, shamans, and other practitioners of earth magic or worship, because they have effectively been actively cultivating the trust of the Earth spirit. If they don't produce energy, they might at least have special personal immunity from the otherwise hostile natural environment. [Answer] Biomass burner or bioconverter to energy is not a bad idea. Plants do not only have desired parts, depending on the plant, they also have leaves, roots, stems, etc... which can be used to convert to life energy to harness the power of the crystals. Thus the harvest will not be used for energy, but the byproduct. It could also be the act of harvesting (killing) the plants that releases the energy. You could simply state crystals require life energy to release their power to justify the need to collect life energy, either through elementals or through (lots of) plants. [Answer] Mycorrhizal networks: <https://en.m.wikipedia.org/wiki/Mycorrhizal_network> A feature from real life that has seen more use in sci-fi in recent years such as the electrical network in Avatar and the mycelial network in "Star Trek: Discover how to write please". Mycorrhizal networks let plants and trees give nutrients to their surroundings, which probably helps young plants get nutrients and grow in the early stages. The fungus involved can take some of the nutrients for itself, rewarding all participants. Some trees have abused this network to pump toxins for other plants into the ground, clearing a space for itself. The network would be used to feed and power the crystal. The player would farm plants that give specifics to the crystal while trying to keep the farmland clear of plants that either produce little or actively kill off nearby plants. You could perhaps even expand this with some meat-eating plants like oversized pitcher plants and add farm animals/traps to the mix, each contributing their own unique nutrients and energy. ]
[Question] [ So, A bit of a long winded explanation: I am designing a world that is meant to be both nostalgic and alien; A world that is familiar enough at first glance, but has many differences to ours. One difference I thought of is a difference in steam locomotives; in our world, steam locomotives were mostly built cab-backwards, as it is exceptionally difficult to shovel coal into the firebox of a cab-forwards locomotive. The few cab-forwards locomotives that were built were mostly oil burners, as oil can be pumped in from a rear tender without the use of a shovel. For this to represent the majority of locomotives, I figure oil would have to be the main source of fuel during the industrial age, rather than coal. Over the previous 500 million years, what environmental conditions would result in crude oil being generally easier to access than coal? Or, if there is an easier way to justify cab-forwards steam locomotives dominating the rails during the age of steam, what is it? And, also, what other differences in the world and society would result from the changes required to make this happen? [Answer] **The answer is a little more than just geology.** Consider these (Earth) maps: [![enter image description here](https://i.stack.imgur.com/citKE.png)](https://i.stack.imgur.com/citKE.png) [![enter image description here](https://i.stack.imgur.com/JTryN.png)](https://i.stack.imgur.com/JTryN.png) [![enter image description here](https://i.stack.imgur.com/1yKFU.png)](https://i.stack.imgur.com/1yKFU.png) [![enter image description here](https://i.stack.imgur.com/ijXp4.png)](https://i.stack.imgur.com/ijXp4.png) The first map depicts worldwide coal deposits; the second, worldwide oil deposits; the third, the spread of industrialisation in Europe; the fourth, the worldwide spread of industrialisation by 1850. Notice the correlations: oil is basically available everywhere the Industrial Revolution *didn't* happen (the UK, the US, the newly unified Germany). Or conversely, the conditions that allowed for religious, social, cultural, scientific, and technological progress to create the IR happened where oil was scarce to non-existent. It did happen where there was, fortunately, some coal: the UK, the US, Germany. **So what does this mean?** Rather than messing about with geology and oceanography, it would be much simpler, I propose, to place whichever cultures in your world have a similar conglomeration of proper religion, social values, cultural perspective, etc that will lead to rational science and the development of technology to the point where industrialisation can happen *in a place where oil is prevalent* rather than coal. Simply that! As for your subquestion, it might be possible that internal combustion engines are devised sooner; since natural gas often goes along with oil, whaling as an industry would be doomed before it could destroy the world's whale populations (whale oil is what was used for lighting and so forth in the early 1800s); plastics might come along sooner. Certainly the wonder drug that petrolatum (i.e. petroleum jelly) would have been discovered much earlier. [Answer] Petroleum has an important property that coal does not: it's a liquid. And when it's kilometers underground, it's under tremendous pressure. If there's pressure from below (as for instance due to water invading the strata that contain the oil), any crack in the overlying impermeable rocks will lead to the petroleum percolating upward -- through the cracks and into the soil or permeable rock layers above. If all of this happens near the peak of an anticline or dome structure (which are natural traps for oil and natural gas in the real world), near enough to the ground surface, a "seep" will appear above ground. This is the source of, for instance, the La Brea tar pits -- but the oil that came up there rose slowly enough for the volatiles to evaporate off and leave only the heavier fractions ("tar") to act as a trap for animals over a period of millennia. If the same thing occurred with a higher flow rate and/or lighter crude (say, in Pennsylvania, where early wells often produced gasoline straight from the well head, instead of California), the seep might make large quantities of petroleum available directly at the surface, where one need merely collect it like the water from a spring -- then filter and refine. And again, if the crude is very light, little refinement would be needed to give a fuel much like kerosene (paraffin, if you're a British speaker) or naphtha. [Answer] ### Higher sea levels historically Most coal comes from land life forms, most oil comes from sea life forms. As summarised by this [helpful graph](https://what-if.xkcd.com/101/): [![enter image description here](https://i.stack.imgur.com/isJJv.png)](https://i.stack.imgur.com/isJJv.png) That link goes into a short discussion of exactly how complex this process is, but in simple terms - land life->coal, sea land->oil. Were the sea levels historically much higher, and the land you're currently occupying was ocean until only a few million years ago, your hydrocarbon resources would be more oil than coal. You'll still need *some* land life (as you need to, you know, evolve), so you'll still get some coal, but more sea life over the land you intend to mine, more oil deposits. [Answer] A lot of natural coal was produced during the [Carboniferous era](https://en.wikipedia.org/wiki/Carboniferous): > > The Carboniferous (/ˌkɑːr.bəˈnɪf.ər.əs/ KAHR-bə-NIF-ər-əs) is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago (Mya), to the beginning of the Permian Period, 298.9 Mya. The name Carboniferous means "coal-bearing" and derives from the Latin words carbō ("coal") and ferō ("I bear, I carry"), and was coined by geologists William Conybeare and William Phillips in 1822. > > > Based on a study of the British rock succession, it was the first of the modern 'system' names to be employed, and reflects the fact that many coal beds were formed globally during that time. > > > The reason why a lot of coal was formed back then is twofold: > > The large coal deposits of the Carboniferous may owe their existence primarily to two factors. The first of these is the appearance of wood tissue and bark-bearing trees. The evolution of the wood fiber lignin and the bark-sealing, waxy substance suberin variously opposed decay organisms so effectively that dead materials accumulated long enough to fossilise on a large scale. > > > So if your world never develops ligning or suberin, there you have it. But that would means no trees as we know them. Rather, you could have these appearing much later in the history of your world. **Edit:** [Alexander](https://worldbuilding.stackexchange.com/users/32451/alexander) also suggested in a comment that if lignin-eating fungi evolve earlier, they may prevent a lot of coal formation from the Carboniferous too. > > The second factor was the lower sea levels that occurred during the Carboniferous as compared to the preceding Devonian period. This promoted the development of extensive lowland swamps and forests in North America and Europe. > > > Which resonates with [Ash's answer](https://worldbuilding.stackexchange.com/a/194499/21222). ]
[Question] [ For some context, my world takes place in the year 2027, just close to a two decades ever since the Black Flu pandemic ripped across the human race and the zombies initiated the Great Collapse, leading to the fall of modern civilization. The US Government was able to somewhat survive and in 2009, under the leadership of President Obama, the surviving remnants of the federal government and US military liberated Washington, DC from both zombies as well as hostile militias, bandits, terrorists, etc. As of 2027, the [District of Columbia has expanded in size](https://i.stack.imgur.com/shhRa.jpg) and has a population of 810,000 people (might jack the number up to a million). Anyway, now that you have some insight, here’s my military: The **United States Garrison** (**U.S.G.**) also referred to as the **U.S. Garrison** and simply the **Garrison**, is the modern post-Black Flu incarnation of the old pre-Black Flu United States Armed Forces. Established on November 11th, 2010, the United States Garrison is by far the strongest, most powerful, advance, well trained, disciplined, and experienced military in all of North America (if not the entire Western Hemisphere) and is responsible for conducting land, aerial, naval, expeditionary, and amphibious warfare. The strength, power, experience, and iron discipline of the U.S. Garrison has made it the premier military of North America. Due to the numbers and resources that it possesses, the U.S. Garrison has spearheaded combat operations, peacekeeping missions, and humanitarian aid services throughout the East Coast while also working to diligently defend the District of Columbia from hostile invaders. The U.S. Garrison was created after President Barack Obama signed the National Defense Reorganization Act of 2010 (NDRA). The Garrison was formed under President Obama’s tenure due to the need to unify the scattered resources and manpower of the five branches of the old U.S. military in order to more strategically and productively utilize the limited resources available. **MANPOWER** Total Number of Troopers: *75,000 Troopers* Active Duty: *62,216 Troopers* Reserves: *12,784 Troopers* **Structure** The Garrison is under the administration of the Department of National Defense, which is led by the Secretary of National Defense (who answers to the President of the United States, who also serves as the Commander in Chief). The highest ranking and most senior commissioned Trooper in the Garrison is the Commander General, a five star general who also holds the command office of being the Commander of the Garrison. The Commander General is responsible for leading the Garrison in executing its missions as well as all operations handed to it, including leading, arming, recruiting, training, etc. the Troopers of the Garrison. The current Commander General is Commander General Adam Mars, a former Colonel in the United States Marine Corps before commissioning into the Garrison as a Brigadier General and later rose to command the Garrison Ground Force before being promoted to Commander General. The Garrison is headquartered in the Pentagon located in Alexandria, Virginia while it’s main operating base is Garrison Base Quantico, known as the “beating heart and muscles” of the entire Garrison and its operations. The Garrison is divided into three main cohesive operating components each headed by a General (who reports to the Commander General). These three components of the Garrison act together in a combined arms fashion akin to a Marine Air-Ground Task Force/MAGTF that compliments one another when conducting operations. They are the following (NOTE: the reason why I’m using Marine Corps and Army unit organizational structure names for non-land warfare forces is for ease of organization and structure): **Garrison Ground Force/GARGROF** (General) • 1st Ground Corps (Lieutenant General, 35,984 Troopers) > > 1st Division (Major General, 10,000 Troopers) > > > > > 2nd Division (Major General, 10,000 Troopers) > > > > > 3rd Division (Major General, 10,000 Troopers) > > > > > 1st Brigade (Reserves) (Brigadier General, 5,384 Troopers) > > > > > *SPECIAL UNIT*: United States Garrison Special Operations Command (SOCOM) > > > * 5th Special Warfare Battalion (Colonel, 600 Troopers) + Echo “Titan” Company (Major, 200 Troopers) + India “Fire” Company (Major, 200 Troopers) + Zulu “Shadow” Company (Major, 200 Troopers) **Garrison Air Wing/GAW** (General) • 1st Air Division (Lieutenant General, 15,000 Troopers, 490 total aircraft) > > 1st Air Brigade (Brigadier General, 6,000 Troopers, 175 aircraft) > > > > > 2nd Air Brigade (Brigadier General, 6,000 Troopers, 175 aircraft) > > > > > 3rd Air Regiment (Reserves) (Brigadier General, 3,000 Troopers, 140 aircraft) > > > **Garrison Naval Fleet/GARNAF** (General) • 1st Naval Corps (Lieutenant General, 24,016 Troopers, 55 total warships) * Fleet Flagship: USS Harry S. Truman > > 1st Naval Division (Major General, 12,590 Troopers, 19 warships) > > > * Division Flagship: USS Essex > > 2nd Naval Brigade (Major General, 7,590 Troopers, 18 warships) > > > * Brigadier Flagship: USS Iwo Jima > > 3rd Naval Regiment (Reserves) (Brigadier General, 3,836 Troopers, 18 warships) > > > * Regimental Flagship: USS Green Bay **Public Agenda** **MISSION** • Defend the territory of the District of Columbia (and by virtue/in spirit, the United States) from all hostile threats, foreign and domestic • Preserve and maintain law, order, peace, and stability within the District of Columbia • Support and implement the national military policies and objectives of the United States • Conduct humanitarian aid operations whenever possible • Seize and defend strategic positions and assets critical to the defense of the District of Columbia • Prepare and maintain naval and naval aviation assets in order to project naval strength across the seas and wage naval warfare • Prepare and maintain aviation assets in order to conduct aerial warfare and maintain air supremacy • Assist in reuniting the United States of America • Execute such other duties as the President or Department of National Defense may direct **Assets** **EQUIPMENT/WEAPONS** Individual Standard-Issue Weapons: * M16A5 rifle w/20-round straight-body magazines * M1911 (SNCOs and Officers-only) * M4A1 carbine w/30-round magazines (Special Operations Command/SOCOM-issued only) * SIG Sauer M17 pistol (Special Operations/SOCOM-issued only) Crew-served Weapons: -M249 SAW * M240 MG * M40A3 bolt action sniper rifle * M2010 sniper rifle * Mk 18 AWM * M110 SASS * Barrett M82A1 * GAU-17 minigun * Soltam K6 120 mortar * M777 howitzer **VEHICLE ASSETS** M1 Abrams (450) * Bradley Fighting Vehicle (390) * Stryker APC (470) * LAV-25 (483) * AAV (280) * MRAP (320) * M1117 ASV (515) * M142 HIMARS (400) * M109 self-propelled howitzer (375) * M939 truck (915) * Landing Craft Air Cushion (12) Total Ground Vehicle Assets: 4,180 Vehicles **AVIATION ASSETS** Fixed-Wing Aviation Assets: * A-10 Thunderbolt (30) * AC-130 (4) * C-5 Galaxy (15) * C-17 Globemaster (20) * C-130J Hercules (25) * E-3G Sentry (3) * Boeing E-4 (3) * F-15 Strike Eagle (16) * F-16 Fighting Falcon (22) * F-22 Raptor (10) * KC-10 (6) * Boeing VC-747 (1) * F/A-18 Hornet (22) * AV-8B Harrier II (10) * F/A-18F Super Hornet (10) * Total Fixed-Wing Aviation Assets: 197 fix-winged aircraft * Rotary-Wing Aviation Assets: * UH-1N Huey (24) * Bell 412 (22) * MH-60T Jayhawk (20) * MH-65D Dolphin (15) * AH-1W SuperCobra (24) * CH53-E Super Stallion (26) * Sikorsky SH-3 Sea King (4) * Sikorsky UH-60 Black Hawk (5) * MH-6 Little Bird (35) * AH-64 Apache (25) * V-22 Osprey (30) * CH-47 Chinook (10) * Bell 206 (30) * Airbus Helicopter H125 (2) Total Rotary-Wing Aviation Assets: 272 rotary-wing aircraft Drone/Unmanned Aviation Assets: * Northrop Grumman RQ-4 Global Hawk (15) * MQ-9 Reaper (6) Total Drone Aviation Assets: 21 drones Total Manned Aviation Assets: 469 manned aircraft Total Aviation Assets: *490 aircraft* **NAVAL ASSETS** Critical Naval Assets: * USS Harry S. Truman (Nimitz-class aircraft carrier) (Fleet Flagship) * USS Lewis Chesty Puller (Lewis Chesty Puller-class battlecarrier) * USS Kurt Chew Een Lee (Lewis Chesty Puller-class battlecarrier) * USS Essex (Wasp-class Landing Helicopter Dock/LHD amphibious assault ship) * USS Iwo Jima (Wasp-class LHD amphibious assault ship) * USS Green Bay (San Antonio-class amphibious transport dock) Fleet Assets: * Arleigh Burke-class guided missile destroyer (20) * Ticonderoga-class guided missile cruiser (11) * Los Angeles-class attack submarine (3) * Cyclone-class patrol ship (9) * Legend-class Coast Guard cutter (4) * Hamilton-class Coast Guard cutter (2) Total Naval Assets: *55 warships* [Answer] # There's a big difference between owning and operating **Owning? No problem.** I see two different questions here. The first is *is it possible for the DC government to own this pile of military hardware?* The answer is yes. We have room for all that hardware. The ships may have been at sea during the insurrection and out of reach of the enemy forces. One radio call could have gotten them to the greater DC area where they could drop anchor. I live in the District and we have enough runways between our civilian airports and military bases that we could park a whole bunch of aircraft. Between the National Guard armory, military bases, and law enforcement buildings, we could fit tons of other kinds of weaponry. Getting the stuff here and finding room to store it isn't a problem. After all, the United States already has places where we store ships and aircraft for decades at a time with minimal staffing. Davis-Monthan AFB (shown below) has 4,400 aircraft managed by the relatively small 309th AMARG. [![Arizona aircraft boneyard](https://i.stack.imgur.com/tW5OZ.jpg)](https://i.stack.imgur.com/tW5OZ.jpg) **Operating? A problem** Here's the more important question: *could a nation-state of fewer than one million residents support the deployment of this kind of firepower?* The answer is a definitive no. Let's start by looking at your aircraft carrier. RAND analyzed [aircraft carrier maintenance cycles](https://www.rand.org/pubs/research_briefs/RB9316.html) in real world conditions and found that carriers are only deployed 19% of the time (shown in green in the chart below). As RAND puts it, "These ships, which are among the most complex weapon systems the Navy operates, require continuous and regularly scheduled maintenance." [![RAND Corporation analysis of aircraft carrier readiness cycles](https://i.stack.imgur.com/OvVwS.gif)](https://i.stack.imgur.com/OvVwS.gif) Supporting force readiness is a big job. Check out the org chart for the 50,000-employee Naval Sea Systems Command. Your smaller navy won't need quite as many divisions, but you'll still need a lot of experts in different fields to support a nuclear carrier and other large ships. [![NAVSEA org chart](https://i.stack.imgur.com/n3nWx.jpg)](https://i.stack.imgur.com/n3nWx.jpg) Your aircraft and ground vehicles also require maintenance and support. According to [this analysis](https://www.defense-aerospace.com/articles-view/feature/5/179243/navair-projects-f_35-to-need-50-maintenance-hours-per-flight-hour.html), every flight hour of the F-35 could require 50 people-hours of maintenance. Bradleys and Abrams need less maintenance but you'll still require specialized mechanics and facilities to keep them operating. Beyond the hands-on maintenance, repair, and training requirements, you'll also need to manufacture ammunition and replacement parts and you'll need fuel and electricity. I'm reminded of [this answer](https://worldbuilding.stackexchange.com/questions/54976/how-long-would-it-take-to-create-a-windows-1-0-capable-machine-from-complete-scr/54981#54981) to an unrelated question where the author listed all the industries you need just to build one rudimentary computer. Realistically, 999,999 of my neighbors and I could support a handful of patrol boats, a few easy-to-maintain aircraft, and a number of heavy vehicles. [Answer] **Make your nation bigger.** Clearly you love the military and all their sweet stuff. And you want what is essentially the US Military to be fighting they way they do now in a near future post apocalyptic environment. That is what you need to have! That is where your passion is. To keep the sweet military you just need a bigger population. And fortunately you can have it. I think you are keen on DC too, so keep that. But expand their area of control to be much larger. Large enough to have a population that can support a standing army of the size that you want to work with. An army with the stuff you list would have no trouble defending a reduced sized US. And you will want them to be battling equals: comparably armed warlord mini-nations, zombie hordes, kaiju - not rinkydink militias. --- I do think it would be fun fiction to have your army own military assets they don't really know how to use or maintain. Having your tanks fall apart as you are trying to use them makes for exciting fiction. [Answer] ***LOGISTICAL HANDWAVIUM:*** This scenario requires a LOT of handwavium to justify, especially without adding some really extraordinary tech. * Assume the federal government has become an absolute dictatorship, complete command economy where the people are serving purely for the sake of preserving the federal government. Despite the fact the district could be concentrating on expanding the safe base around the city, expanding agriculture, etc, they are instead reaching out in an attempt to rebuild the federal government. Then assume the survivors they encounter are interested in supporting the federal government, instead of their village, city, and state. * Assume the federal government has built a giant series of military bases around DC prior to the apocalypse, since you don't have the economy to build them after. A MASSIVE buildup of equipment (especially maintenance equipment and spare parts reserves) were put here as some sort of political statement by a previous administration, ignoring the risk of nuclear attack and concentrating most of the equipment reserves of the old USA in and around DC. * Assume federal law or some sort of legal requirement by interfering state governments prior to the war caused a large number of defense contractors to produce their weapons in or near the capital. The engineering expertise to simplify and update equipment was concentrated here. * Assume Norfolk VA was the exclusive naval maintenance facility for the USA (possibly due to those same considerations) and that it survived completely intact from the apocalypse. This starting premise isn't too bad, as this is already the biggest naval base in the world. * Assume due to political reasons the USA assured critical infrastructure (smelting plants, etc) and HUGE strategic reserves in the immediate area of the capital, including thousands of tons of steel, millions of tons of surplus food, and millions of barrels of oil. * **NOW:** Idle 90% of this stuff as being impractical in an actual zombie apocalypse. You don't need most of the air power, and you don't need most of the sea power. Sure, it's there, but a cargo ship filled with soldiers will be a lot more useful than an aircraft carrier. Each one of these ships requires a huge crew. They would mostly get parked somewhere and used as bases and landing strips. I saw a game once where the USS Constitution was equipped with 50 cal machine guns and turned into a pirate ship. The modern equivalent would be more practical - sailing ships with engines for maneuvering, to minimize fuel consumption (modern ships are starting to look into similar options - it just proves what comes around goes around). * The scenario that justifies all this handwaving is if there was a conspiracy going on prior to the zombie apocalypse that knew it was coming, and prepared for it in advance. Personally, I wouldn't pick DC if I were a conspirator, but hey, why not? The conspiracy would be decades-long. Maybe someone WANTS the USA to become the only superpower, and a deeply authoritarian one, at that.Who knows the motives of conspirators? Sounds like a good back-story... ]
[Question] [ In terms of scientific and engineering challenges, which one is closer to fruition? Specifically I am looking for the feasibility of using one of these systems for space-only travel between the orbits of planets and bodies throughout our solar system. Bonus points if the propulsion system can maintain constant acceleration, like the ships in The Expanse, and provide crew members with some fraction of Earth gravity. [Answer] Antimatter is a battery. Fusion is a generator. They're good for different things. Unless we find a way to mine antimatter from some source we don't yet know, it will only ever be stored energy, made with planetary particle accelerators (or some future alternative), and every gram made will require input of its mass equivalent in energy. Fusion, on the other hand, has at least the potential for portable power systems and engines, likely even capable of refueling "in the field", either from dense nebulae, or from planetary atmospheres and oceans. Antimatter has a far higher energy density and release rate -- fusion has a much longer duration of action. It's like the difference between gunpowder and gasoline, only far more so. For some things, you need lots of energy, all at once -- that's a potential application for antimatter. For other things, you need your energy to be delivered over time -- that's a better place for fusion. [Answer] Fusion power. In fact, we (probably) have done all of the basic science that's needed to build fusion power plants, the only thing that remains is a very expensive development process. The process of fusion is pretty well understood: you cram a bunch of very hot hydrogen together, it fuses into helium, and releases a bunch more energy. You use that energy to boil steam, and after that a fusion power plant looks just like a regular coal, gas, or nuclear power plant. The problems are technical, not conceptual: 1. How do you reliably start a "cold" fusion reactor by cramming enough hydrogen together and getting it hot? 2. Once the fusion reaction is started, it generates so much heat that any fusion reaction naturally wants to blow itself apart. So how do we keep that fusion reaction stable enough that we can keep feeding it new hydrogen and keep the reaction going? These are really questions of the geometry of the reactor, of the mechanisms that need to be built, of how many and how strong of magnets do we need to confine the reaction, etc. We will have to do a lot of very expensive modeling and simulation, then build prototypes, then go back to the design stage and improve those prototypes, then build more prototypes. Eventually we get to the point where all of the apparent kinks are ironed out and we will build the world's first pilot fusion plant. That will be another big learning experience, and probably 5-10 years after that you will see the first generation of Mark 1 fusion reactors starting to be installed around the world. The only problem is that all of this is terribly expensive. Unless there is a clear and convincing reason to spend billions to trillions of dollars developing this technology, it's much cheaper not to. From a technical standpoint nuclear power is just as clean as fusion power would be, and in the modern era there's much more of a focus on making renewables incrementally cheaper and more efficient rather than building a whole new technology. (Note that the problem of nuclear waste and nuclear contamination are more political problems than technical problems.) This is what caused one of the early fusion pioneers, Lev Artsimovich, to say, "Fusion will be ready when society needs it." The science is done, but the very expensive development has never been funded. Fusion has been "20-30 years away" since the 1950's because we got to the point where we can't go further without massive investment, and that investment just hasn't happened. [Answer] **Fusion, but probably with an antimatter boost.** Simply put, we have been working on it for decades and are already on our way to having it. It has already been noted in other answer's and in comments that one of the biggest differences is that fusion is much better for sustained energy release, while antimatter releases more energy immediately. A purely antimatter drive would probably be more akin to early designs of exploding nukes behind a rocket, except it would be detonating antimatter (in layman's terms). Likewise, our current ability to produce antimatter is heavily limited by energy production and confinement (described as a magnetic bathtub in a documentary I saw once), which will likely be supplemented by the completion of fusion reactor designs. I would like to note that fusion reactors and fusion rockets are two different things, but it stands to reason that once you have reactors, rockets aren't too far behind. Personally, I am much more convinced that something between spiked fusion rockets and [antimatter-catalyzed nuclear pulse propulsion](https://en.wikipedia.org/wiki/Antimatter-catalyzed_nuclear_pulse_propulsion) are much more likely to become the standard. *Feel free to correct me if I'm misunderstanding literal rocket science.* Basically, fusion and/or fission rockets are the primary propulsion method, however antimatter is used to essentially supercharge the entire reaction. This works differently for fusion vs fission, but in either case the end result is much greater impulse and fuel economy from the drive than you would get with either method on it's own. For inertial confinement fusion it would save the initial energy investment necessary to start the reaction. Some design variants speculate much higher plasma gain and/or impulse. For a fission rocket using the nuclear pulse propulsion design (back to firing nukes behind the rocket) it would essentially give you more bang for your buck. The comparison as I understand it is essentially turning your gen-1 A-bomb into a thermonuclear H-bomb (grossly over simplified). [Answer] Rockets which use antimatter as their primary source of energy are perhaps easier to conceive of and make than most fusion rocket designs (because you just throw some antiparticles at your reaction mass, and blow the resulting *kaboom* out of the back of your ship via a rocket nozzle, probably a magentic one, job done) but the sheer unimaginable cost of producing and storing the damn stuff in bulk will stop any such plans dead. By "bulk" I mean "milligrams" here, by the way. Getting lkarge amounts is going to require vast infrastructure built in space, which will be the end product of a mature spacefaring civilsation, and such a civilisation will have need of decent rockets. *Something* will have to come first. The easiest solution is of course the good old [Orion Drive](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)), which offers good efficiency and high thrust-to-weigh, and might well be possible with modern day technology. Most of the *boom* of modern nuclear weapons is provided by fusion reactions, after all. Job done! This isn't an entirely smooth thrust, of course, but non-pulsed nuclear engines are likely to be exceedingly hard to make... witness our inability to make net-positive-output, non-pulsed nuclear reactions on Earth, and getting *anything* of that sort of work will be much easier than harnessing it as a powerful rocket of the sort that will shove you around the solar system. No; your best bet will be some kind of pulsed nuclear propulsion... designs like the [Magneto-Inertial Fusion](http://www.projectrho.com/public_html/rocket/enginelist3.php#mif) or [Magnetized Target Fusion](http://www.projectrho.com/public_html/rocket/enginelist3.php#hopemtf) seem relatively plausible, and both are pulsed, for example. --- > > Bonus points if the propulsion system can maintain constant acceleration, like the ships in The Expanse, and provide crew members with some fraction of Earth gravity. > > > As a footnote, be aware that brachistochrone transits may be fast, but they require very, very high performance engines. Centrifugal gravity combined with much more modest boost-coast-brake transits will be vastly easier, and allow for clever external beamed propulsion systems to maximise efficiency and leave the heaviest and most inconvenient parts of your rocket at home. ]
[Question] [ My magical civilizations have a unique type of magic, material magic. This magic allows them to improve strength and hardness of wood. As an example: with a cannonball, the magically treated wood offers protection against penetration of ~2 times the thickness of normal wood. (As for use of bamboo in ship building, it can also be magically refined in a same way). What we're working here with are pre-industrial age of sail ships, things like Western carracks (something like [Mary Rose](https://en.wikipedia.org/wiki/Mary_Rose))/possibly early galleons and Eastern djongs/junks ([Chinese treasure fleet](https://en.wikipedia.org/wiki/Chinese_treasure_ship)). I understand that my material improvement might allow slightly larger ships, and that they will also be able to carry more cargo. Warships will be able to take more cannon beating. Perhaps there are some other things that I've missed, but I assume the change isn't too drastic, it just shifts the qualities of ships slightly in the direction of iron ships. I'd welcome a correction if I am wrong though. There however is another important thing to consider. My material magic also allows woodworkers to join/connect wood, as if it was always one piece. No need for nailing planks together, and the end result is that ship is as if it was carved out of a single tree, even though it wasn't. As far as I know, medieval ships size were very dependent on tall trees, and I cannot imagine how the ability to connect pieces of wood like that would change limits of shipbuilding. **So, I need to ask, how would such magic ability change the warships built?** How would this impact things like size and design of such warships? [Answer] I have a few things to note that have not yet been covered in other answers. * Flexibility: traditionally, wooden shipbuilding used a time-consuming process called **Steam Bending** to temporarily soften pieces of wood in order to plastically deform them into the necessary curved shapes. If a mage can do that faster with magic, construction could go substantially faster. * Structure: A ship's frame bears most of the forces the ship is subjected to. In theory a hull could be made thick enough to withstand such forces, but to do so in our reality would require so much extra wood and add so much extra weight that it's never done. Instead, hulls are made as thin as is practical given the conditions they will face (coastal and river [brown-water and green-water] ships can have thinner hulls than high-seas [blue-water] ships, trading ships can have thinner hulls than warships, et cetera). The hull is mounted on a complex structural frame that attempts to maximize strength while minimizing weight. The complexity is partially caused by the fact that wood's strength against any force varies greatly by the force's orientation relative to the grain, and thus the frame is made of many short timbers arranged to be in the best direction for the stresses each will endure, and braced at the joints with more timbers that distribute the stresses across the entire frame rather than letting it concentrate at a single point. In your world, however, the ability to seamlessly fuse pieces of wood to the extent of joining their grain structure allows you to do away with a good portion of this structure and make your ships lighter and more spacious for the same strength. The densification helps with reclaiming a bit of interior space as well. You still need extensive bracing fore and aft and beam to beam to resist buckling, bending, and twisting, but not nearly as much. Care *does* still need to be taken with the directions of the fused wood grains, as mentioned. The hull would benefit by having layered grain structures orthogonal to each other for maximum pressure resistance - you could produce something like a **Monocoque** made of a fusion of **Marine Plywood** and **Cross-Laminated Timber**, which would let you have even stronger hulls for the same weight. * Failure modes: the **Strength of Materials** involves more than hardness. You said that the magic system can improve wood's **Impact Strength**, but you also want to figure out what your magic *can* and *cannot* do in terms of **Compressive Strength**, **Tensile Strength**, and **Fatigue Strength**. Under normal conditions, wood cracks when any of these strengths are exceeded - and the more force it took to reach the breaking point, the more dramatic it will be when that force is released. * Fire resistance: Densified wood tends to char rather than be consumed by fire, which will help limit the spread of shipboard fires. Ropes and sails will still be extremely vulnerable, unless your world includes some way of fireproofing them as well. * Masts and Rigging: Mast failure by bending and ultimately cracking (known as a "sprung mast" if it doesn't just snap off completely) became a major problem as ships got bigger and got more sails, which put extreme strain on the masts. In our world, this was combated by adding extensive webs of "standing rigging", strong ropes that ran between the top of a mast and the frame of the upper deck in the same way that a modern radio tower is supported by guy wires. As masts got ever taller and the forces on masts became ever greater, even extensive standing rigging was often insufficient, and it became common and then standard for masts to be reinforced by wrapping them at intervals with tightly-coiled rope and/or iron hoops. These helped keep the wood fibers from separating under bending stress. With your magic, it sounds like it would be feasible to clad a vertically-oriented core with a layer of horizontally-oriented fibers joined into complete loops, which should offer comparable strength increases. There is also the potential of magically joining wooden beams horizontally between masts to add support in compression (compared to rope, which is only strong in tension) and diagonally from frame to mast to act as buttresses. * **Biofouling**: All ships and boats (and any other structures in the water), no matter what they're made of, are subject to the buildup of a layer of aquatic life including seaweed, algae, barnacles, tube worms, and hundreds of other species. This rapid buildup makes the surface increasingly rough, causing turbulence and drag that can slow a ship by up to 10%. Ships need to regularly undergo maintenance to clean their hulls and counter these effects. Wooden ships also have to deal with **Shipworms**, a group of molluscs that bore into - and eventually destroy - any submerged wood. The only effective long-term protection against shipworms in our world has been to fasten copper sheathing to the hull up to the waterline (which also conveniently reduces biofouling, but inconveniently prohibits the use of iron nails as it hugely accelerates their corrosion). Other metals like lead and iron are notably heavier and corrode quickly, making them impractical. A sacrificial non-structural layer of wood was sometimes used, which temporarily shielded the structural hull from damage and needed to be replaced frequently. Various toxic coatings have also been used, but they pose a health hazard and need to be reapplied frequently to maintain their effectiveness. *Anything* magic can do to ease this problem will give any navy *with* magic a substantial advantage over any *without*. * Cost: This magic has the potential to drastically reduce the cost of *building and maintaining* a ship, especially with regards to time. Doing away with nails will save a *huge* amount of money and time (as @Kepotx says, nails are very time-consuming to make without industrialization and/or metalbending, and sometimes a ship would need to have its hull completely disassembled just to replace corroded nails before the bottom of the ship falls off). A less complicated frame cuts down on construction time significantly. Being able to manipulate "living material" strongly implies the possibility of magically removing biofouling, and unless such magic is itself time-consuming and difficult/rare, it would almost certainly be easier than having to manually scrape off the fouling. If that defouling can be done from *inside* the ship, without needing to careen it or use a drydock, the time and effort savings would be *enormous*, as it could be done without taking the ship out of service at all. Repairing a ship, as @DarthDonut mentions, will be a much smoother process as cracks can be directly mended and holes can be patched without having to remove and replace damaged planks. Faster repair means greater reliability and less time out of service. Being able to turn small pieces of relatively low-quality wood into a single long, uniform, high-strength beam means that masts can be made from whatever trees are nearby, instead of needing to find trees with the desired height, thickness, and straightness, and again saving time and money. **Further Reading:** [*The Mechanical Properties of Wood* (1914), by Samuel J. Record](https://www.gutenberg.org/files/12299/12299-h/12299-h.htm) [Unrestricted webpage and e-book] - Details the strengths and weaknesses of wood under mechanical stress. [*The Structures of English Wooden Ships* (1993), by Trevor Kenchington](https://www.cnrs-scrn.org/northern_mariner/vol03/tnm_3_1_1-43.pdf) [Unrestricted PDF] - A description of the structure and construction of English ships circa 1710, based on a contemporary book written by William Sutherland after a career in the Royal dockyards, particularly at Portsmouth and Deptford. Walks through the entire structure of a three-decked ship-of-the-line. [*Illustrated Glossary of Ship and Boat Terms* (1994), by J. Richard Steffy](https://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199336005.001.0001/oxfordhb-9780199336005-e-48) [Unrestricted webpage and PDF] - Provides definitions, descriptions, and illustrations of the nautical terms used in Kenchington's paper, among many others. Excerpt from Steffy's book *Wooden Ship Building and the Interpretation of Shipwrecks*. Published as part of [*The Oxford Handbook of Maritime Archaeology*](https://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199336005.001.0001/oxfordhb-9780199336005), most chapters of which are restricted to online subscribers and people who buy the book [Restricted e-book, hardcover, or softcover] but which also contains a great deal of additional information on ship design throughout history. [History of Masts, from the National Museum of the Royal New Zealand Navy](http://navymuseum.co.nz/history-of-masts/) [Unrestricted webpage] - Provides details of mast construction [*The Elements and Practice of Rigging and Seamanship* (1794), by David Steel](https://www.hnsa.org/manuals-documents/age-of-sail/the-elements-and-practice-of-rigging-and-seamanship/) [Unrestricted webpage] - Provides ***extensive*** detail on all aspects of a ship's rigging, including ropes, masts, sails, anchors, and blocks (pulleys), as well as detailed descriptions of seamanship, the practice of working ships, and naval tactics. [*The History of the Prevention of Fouling* (1952), from the U.S. Naval Institute](https://darchive.mblwhoilibrary.org/bitstream/handle/1912/191/chapter%2011.pdf) [Unrestricted PDF] - Explains some of the methods that have attempted to counter biofouling, for both wood and metal hulls. [Answer] On which parts of a ship could this magic be used? 1. **The hull:** Ships during the Age of Sail had always the problem with water coming in through small gaps in the woodwork of the hull. A fused wooden hull would be (nearly) completely waterproof, and as such reduce the need for bilge pumps. You won't remove them completely, because you need them in case of hull damage and storm water, but you won't operate them 24/7. The stability of the hull would be better than traditionally build ships, because at the end of the process your hull would be a single fused piece. With this in mind, your ships could weather storms better, and would be seaworthier than normally built designs. 2. **Ropes:** Most ropes were made from hemp, and as such it should be possible to strengthen them. The result would be something along the line of sturdier ropes that don't break as often. 3. **Mast:** As Henry Taylor pointed out in his answer, the mast height could be improved as far as the ship would not become top-heavy. 4. **Sails:** Made from organic material, the sails could be reinforced like the ropes and as such be made thinner or bigger. They would not tear as easily, reducing the needed repairs. 5. **Repairs**: Say someone put a hole in your ship. Say you have a mage on board. Depending on how this magic is applied, you simply take a wooden board, put it on the hole, the mage sings, dances or puts his hands on the wood, and vóila! Repaired hull. One could also go as far and use sawdust to patch things up by mending the dust to real wood. To conclude: Your ships would most likely become lighter(and thus faster), bigger, sturdier and easier to repair in comparison to your mundane rivals. Soon you will reign supreme on the seven seas! [Answer] Greater mast heights (from joining the lengths of multiple trees) and greater mast strength with no increase in weight should provide more wind catching capacity and therefore greater cruising speeds. Doubling the hardness of the hull would also increase the effectiveness and safety of ramming other vessels which lack the wood magic. [Answer] ## Easyer maintenance **TL;DR: no need to replace the nails anymore.** Other answers already cover how a stronger wood make a better ship. But the construction, or repair on plain sea is not the only thing you should care about a ship, there is also maintenance, and your magic wood will help it. Also, a better wood is not the only advantage, there is also the lack of metal nails. > > My material magic also allows woodworkers to join/connect wood, as if it was always one piece. No need for nailing planks together > > > This, is a *great* advantage. I once visit [albaola](http://www.albaola.com/en), a place where they rebuilt the san juan, a ship from the 16th century. One interesting part was the cost of the nails. Today, a nail cost only it's weight on metal, but is easy to make. However, it's much longer to do it with pre-industrial technology. This will save you a lot of time/money for the construction, but not only. Nails rust. You need to replace them quite often. this almost means you should re-create tons of nails, and replace each of them, basically rebuilding the ships. Treenails (nails of wood) were also used, but they can't always replace nails. [Answer] **Cost and locations of Construction:** One of the biggest impacts that being able to magically work wood for a ship building industry is going to be a vastly reduced cost to build, as well as opening up far more regions to effective Big Ship industry. While large trees would probably still be prized for their prestige and reduced wood-mage labour requirements, regions with smaller trees could still produce larger vessels while having less risk of industry collapse due to over harvesting. Rate of ship production becomes more like modern pulp and paper industry: How much land can you have around a shipyard, and how much 'reasonable growth' wood product can you harvest off it in 20-40 year cycles. Your labour can focus on lower skill wood harvesting and working as well. Handling and shipping wood off a 30 year old tree, which you can cut into lengths short enough for a single man to pick up on his own, takes far less skill and effort than cutting and handling 500 year old growth... Large ships can then be built out of material cheaply harvested and carted around, rather than relying on heavily specialized material handling. It becomes little more effort than moving local firewood stocks, rather than sending colonists off to far flung reaches of the earth in search of specific old growth lumber. --- However, without improvements to propulsion methods, you are unlikely to see an impact of ships much larger than we had at the end of the age of sail with iron hull vessels. They simply become too hard to handle safely in open ocean conditions, and while shuffling around in ports. ]
[Question] [ The purpose of this question is to get an alien race with a diffused set of organs, which makes any part of their body interchangeable. Why would a species need this? Well for one it might be because they are prone to injury due to the wildlife of their planet. Just like us they make us of tools and have formed a civilization. The main difference between them and us is that they are more similar to jellyfish or starfish in biology. They are capable of regenerating far better than us humans but are also flimsy and soft. **How do they work? What are the advantages and disadvantages of their biology?** Their natural form is a mass of tentacles but after making contact with humans they found it enjoyable to mimic the human form (some kind of trend), although their walk if more of a clumsy wobble. They are mute so humans communicate with them using sign language and writing instead. So far in the story everything is well and good until scientists grab a deceased one for dissection, which is why I need this information. If the question needs refining go ahead and point out what is lacking and editing shall ensue. [Answer] Having no organs would not be viable. But have *many* very *small* organs might be. Though it is still very challenging. It's just not very efficient to spread organs out in this fashion. Instead of a central nervous system they might have clusters of nerves all over their bodies. This might be backed up with chemical retention of memory. So if such a critter got chopped in half, each half could grow back the nervous system and use the chemical backup to restore memory. So instead of a heart, they might have a large number of little pumping stations. Possibly this consists of specialized muscles combined with valves in blood vessels. Instead of lungs they might have many small breathing tubes to many small gas-exchanging structures distributed through their bodies. Instead of kidneys they might have a large number of small filtering structures, each with a duct to the surface. It might make their sweat quite noxious. Instead of a pancreas they might have little secreting bodies distributed over the body. To eat they might excrete some digestive chemical on their food, then reabsorb the results. Again, it might happen through many small ducted glands near the surface. Having the lungs, kidneys, and digestion act in this fashion would probably put very harsh limits on how big this critter could be. The old cube-square ratio gets troublesome very quickly. Double the average size of an object, you make the volume go up by 2 x 2 x 2 = 8. But the surface area only goes up by 4. So quickly, the space available for breathing and excreting waste becomes insufficient. This might be in line with them starting out as mostly "tentacles." A long tubular critter can escape the cube-square by staying the same thickness and getting longer. They could have many little "eye pits" that detected light only in one direction. They would need some very good [proprioception.](https://www.sciencedirect.com/topics/neuroscience/proprioception) Then, by combining their proprioception with the view from many of these pits, they could build an image. This is yet another competing factor for their limited skin surface. [Answer] **Not Possible** I really don't want to say this, because the concept of an alien able to do this is pretty cool. Not to mention the obvious upside that they'd be able to lose body parts with no negative effects. However, you're asking for a reality-check, and in reality? Not a chance. It's not even that you're underestimating just how good specialization is - it's also that organs have far too much to do. Let's go through a list of some major organs: Heart, lungs, brain, liver, kidneys, stomach, large intestine, small intestine, bladder, muscles, gonads, spleen, pituitary gland, thyroid gland... etc. The list goes on. [A lot.](https://en.wikipedia.org/wiki/List_of_organs_of_the_human_body) What you're asking is basically, 'How do I make an alien which can have any organ do the work of any other organ'? and the only possible answer is *simplify*. Notice that you compare these aliens to jellyfish, which falls on the 'incredibly simple' end of the spectrum. It doesn't even have a nervous system - that's the kind of thing you're looking at, something which doesn't require complex things to be done to function. You can't have an organ that can purify blood, or sometimes just pump blood, or have the ability to oxidate blood, or occasionally be responsible for controlling hormones. True, alien biology might be different. But there's a list of things they need to do. They need some way of producing energy, they need some way of circulating that energy throughout their body, they need a waster to remove their own waste products, they need the ability to move, and they'll need the ability to regulate homeostasis. And these aren't simple things, especially at the level of complexity that would be required to produce a creature with the cognitive capacity of human being. Admittedly, it'd be really cool to have an alien creature which is reminiscent of [Sergeant Schlock](https://schlockmercenary.fandom.com/wiki/Schlock), but I'm afraid that, in reality, it's just not possible. [Answer] The only way I can think of this working is if the biological cells themselves of the aliens could rearrange and adapt rapidly enough to form new organs based on what was needed. I think of [kandras](https://coppermind.net/wiki/Kandra). Whether it's possible for all (or most) of the cells in an alien body to function as rapidly adapting stem cells is beyond my knowledge of science, but I think differentiating cells is the only way this could work. [Answer] **This is unlikely to work unless...** I may be wrong in how I interpret your meaning of diffused organs, but I gather this as meaning that the organs are completely free floating and rely on diffusion to supply the body. The reason this is unlikely to work is because specialized tissues and organs rely on being able to be supplied specific inputs and produce specific outputs. In a diffused body layout you lose the ability for the alien to ensure these inputs and outputs get where they are needed. Let's take an example of a few systems and how they lose their ability to function properly without strictly controlling the system. Digestive system Imagine you go to eat something and as soon as you swallow your food starts free floating around your body. This is problematic for your stomach as it would be difficult to absorb the large chunks of food or drink and later release it again without accidentally releasing digestive acids and enzymes. Circulatory system Without having a looping track of veins and arteries it becomes incredibly unlikely that an organism is able to guarantee a consistent supply of blood and nutrients to each of their cells as it becomes more and more likely for the lack of flow to isolate cells further away from the lungs, heart and intestines. **Now for the unless part.** If your alien species has managed to create an extremely flexible, elastic and quick to repair connective tissue that could connect the organs regardless of how far away they floated from each other it would become possibly viable. This is a challenging feat however, being able to stretch and lengthen without constricting would be vital to avoid loss of blood pressure or blockages. It would also need to be able to quickly repair and have knowledge of what it was connected to in the case it gets severed, I think this would be the most alien and as such is beyond what I can suggest. alternatively, as a frame challenge, while you mention the aliens mimic the human form you never mention their size. The smaller the aliens are the less important it is to have specialized cells performing dedicated tasks, as such it may be **your alien mimics the human body while being a single celled organism!** ]
[Question] [ In the 1960s we were disappointed to find that the moon is a pile of dust and rubble with no easily accessible valuable materials. Well, we kind of knew it before that, but we weren't sure. Anyway, this is why no one has gone back in 45 years or so. I am wondering if the following scenario would be plausible, in the hypothesis we had actually found that the moon is made of something valuable, say gold: 1. Accelerated exploration of the moon, with the purpose of accessing the valuable resource. (Problem: Would it have been feasible to profitably transport significant quantities valuable material such as gold from the moon to down to earth with 1960s/1970s technology? If not, would it have become feasible in the subsequent decades?) 2. Collapse of the price of the resource on earth with (or in anticipation of) the first shipments with the resulting economic mayhem. 3. Destabilization of the earth-moon system by shifting a significant amount of mass from the moon to the earth. (Problem: I suspect the mass transported would be negligible in any plausible scenario.) [Answer] Let's make a quick profitability analysis. How much rock did the astronauts [bring back from the Moon](https://curator.jsc.nasa.gov/lunar/)? > > Between 1969 and 1972 six Apollo missions brought back **382 kilograms** (842 pounds) of lunar rocks, core samples, pebbles, sand and dust from the lunar surface. > > > How much did the [Apollo program cost](https://christopherrcooper.com/blog/apollo-program-cost-return-investment/)? > > The Apollo Program cost roughly 25.4 billion dollars, unadjusted. That makes the total Apollo Program cost **163 billion dollars** inflation adjusted to 2008. > > > That means that those stones should be sold at 426 million dollars per kg just to break even with the costs. That would make it **426 thousand dollars per gram**! Gold costs much less than that. As I write this answer it costs 47 dollars per gram, even the research organic materials I used during my PhD for making OLEDs cost a mere 3 thousand dollars per gram. There is no risk of collapsing the economy with any resource you bring back from the Moon because you will go bankrupt before even making a dent in the economy itself! Even if you reduce the costs of moon missions by a factor of 1000, it will still be uneconomical! [Answer] > > Would it have been feasible to profitably transport significant quantities valuable material such as gold from the moon to down to earth with 1960s/1970s technology? If not, would it have become feasible in the subsequent decades? > > > Maybe. Gerard O'Neill (originator of the now-classic [cylindrical space habitat](https://en.wikipedia.org/wiki/O%27Neill_cylinder) design) proposed setting up a [mass driver on the moon](https://en.wikipedia.org/wiki/Mass_Driver_1) in order to provide enough material for his proposed giant lagrange point habitats which would have massed millions or billions of tonnes. Quite how plausible the mass drive was in the 70s I'm not sure, but it wasn't entirely implausible. The problems of constructing and operating industry on the moon, on the other hand, may actually be insurmountable... moon dust is an absolute killer for mechanisms, seals and people. You'd need to attach a rocket and guidance system to every payload the mass driver launches in order to inject it into a suitable return orbit, which may also require heat shielding if it is a direct-return-to-earth's-surface trajectory. That also raises some safety concerns, but hey! It was the 70s, people were more relaxed back then. > > Collapse of the price of the resource on earth with (or in anticipation of) the first shipments with the resulting economic mayhem. > > > Maybe? The initial investment would have been substantially greater than the Apollo program. Unless the minerals were super valuable, useful and easy to acquire and return it would take a looooong time to recoup that upfront cost. There's some scope for the operator to stockpile minerals at the moon side awaiting a favourable market, of course, depending on whether they can maintain a sufficient revenue stream to keep the operation running in the meantime. Really though, I can't actually think of anything that would be worth mining, refining and sending back to earth. Gold would be singularly pointless... if it were found in sufficient volume to justify what might be a trillion-dollar operation, it would devalue existing gold stockpiles and gold just isn't useful enough for there to be a use for the surplus. Back in the 70s, I don't think there was anything that appeared to be scarce [other than oil](https://en.wikipedia.org/wiki/1970s_energy_crisis), and you won't find that on the moon. The only justification for O'Neill's mass driver operation was to construct space habitats, to further support human expansion into space... something also of dubious economic value, alas. In Heinlein's novel, [The Moon is a Harsh Mistress](https://en.wikipedia.org/wiki/The_Moon_Is_a_Harsh_Mistress), the inhabitants of the moon are effectively farmers (and support workers) and ship food back to an overpopulated Earth via a mass driver. Also dubious, but would at least be subject to a different set of economic pressures. With a mature space presence, it *might* be worthwhile using materials mined on the moon to construct, fuel and power space-based infrastructure (eg. [solar powersats](https://en.wikipedia.org/wiki/Space-based_solar_power) which would have direct economic benefits for Earth. Still a very long shot, though. > > Destabilization of the earth-moon system by shifting a significant amount of mass from the moon to the earth. > > > Haha, no. The moon weighs over 7x1022kg. If you could somehow ship a billion tonnes a year, even after a thousand years you'll have only removed less than a millionth of the moon's mass. [Answer] 1. No it would not have been economic to export gold from the Moon in the 1960’s and 70’s on purely economic grounds. It might have become feasible in later decades but it is very hard to say because the primary reason for going to the Moon was political not economic and the financial risk would be huge. Gold is a very volatile currency and plans to make a profit at one level could easily be swamped by market sentiment swinging the gold price in the wrong direction at a bad time. 2. The price of gold has always been very volatile (at least since the end of the gold standard) a few tons would not make much difference as ~3000tons is mined every year. What would matter is what people think might happen so the gold market might go down but I doubt there would be economic mayhem, although things might get worse in later years. NASA’s SLS and all the rest still pose no real problem, but When SpaceX’s Starship starts flying on a regular basis it would pose a serious risk to gold prices due to its anticipated very low cost and 50 ton landing capability. 3. There is not the slightest chance that any human activity on the Moon in the foreseeable future would have any measurable effect on a body such as the Moon. One other key point: I assume that the gold is just lying on the moon in smallish ingots waiting to be scooped up. If any sort of mining or refining is involved the all bets are off for a few decades at least and perhaps indefinitely depending on difficulty level. [Answer] As other excellent answers said, there is no economic sense to move much material from moon to earth b/c the costs are astronomically high, and most of moon is made from stuff already available on Earth. Even if moon has some kind of unobtanium that is worth shipping to Earth, it will be a tiny fraction of moon's mass, and will probably have no substitute on earth's surface. I would like to propose **an alternative scenario**: using minerals and materials from Jupiter's moons to build flying cloud cities on Jupiter itself (if you need an economic reason for that, let's assume Jupiter has sentient lifeforms that are willing to teach us their advanced science) Jupiter's upper atmosphere has no solid matter, so you need material to build human habitats. Getting stuff from Jupiter's moons will be cheaper than shipping it from Earth or Mars or asteroids. Cheapest way to get stuff from moon to Jupiter will be some kind of catapult or railgun (no need for fuel or oxidizer). And I believe that short-sighted/cost-minimizing method of mining and launching will have catastrophic consequences in the long term. Railgun will alter moon's rotation. Single launch site is cheaper than several, single fixed direction of launch is again cheaper, and for a railgun, that direction will be along the surface (to support the lengthy rail). So "recoil" from each launch will spin the moon in opposite direction. Changes to spin will lead to increases tectonic activity. To avoid this, you would need two railguns on opposite sides of the moon, launching matching masses of stuff. If you can launch straight up, you will always launch in direction opposite of moon's orbit, so you will increase speed of the moon relative to Jupiter, so moon's orbit will widen, and it will eventually fly off into space. [Answer] It would not have been profitable for the reasons listed--but the valuable part is that people would keep trying. You would have had hundreds of companies trying to do what SpaceX is just now doing--but decades ago. Just the thought of all that gold would have driven people nuts. We'd probably be decades ahead in certain parts of our space program simply because there was gold to be had. The value of gold is it's rarity though and if they had brought back enough volume they could effect that--at some point countries would just stop trading in gold and start using something else... Even now the value of gold as a currency backing commodity is questionable--it's only real value in backing currency is rarity and we can interduce an artificial rarity though digital means so gold may already be completely unnecessary. ]
[Question] [ I was thinking of a hypothetical species of snakes that join together for protection called *Ladôni*, due to their habit of mobilising in massive beds which make them resemble a large multi-headed snake. *Ladôni* often feeds on dead carcasses although, they'll sometimes hunt young, old, sick or injured prey by attacking it *en masse* with saliva anticoagulants and burrowing into the prey to eat it alive from the inside. Could such a creature exist and if so, what sort of adaptions would it require? [Answer] You could probably create such a species by taking inspiration from several different reptiles and other animals. [Blindworms](https://en.wikipedia.org/wiki/Anguis_fragilis) look deceptively like snakes, but they actually are [legless lizzards](https://en.wikipedia.org/wiki/Legless_lizard). Due to differences in evolution, it's plausible they would have eating habits that differ from that of snakes. It's rare, but not unheard of snakes piling together in earth pits to preserve warmth in areas where the nights can become dangerously cold. Have them evolve in a habitat where small prey gradually went extinct over several generations and you have a plausible reason for the snake-pile seaking out carcasses as a pack. To create a truely multi-headed snake-pile that moves as one into the direction of the next carcass, you could improve their ability to detect smallest traces of the smell of decay. [Vultures](https://en.wikipedia.org/wiki/Vulture) are known to accumulate around carcasses despite having only limited social behavior, simply because all birds in a certain area follow the same scent trail. If your snake-pack sleeps in one place, it's plausible that multiple members perceive the scent trail of the next carcass and other members simply follow because this behavior usually yields a meal. Several species of fish and birds developed movement patterns that keep shoals and flocks together and moving as one unit. The snake-pack doesn't even need very sophisticated swarm-behavior, because they can glide over each other without causing them to crash or being eaten. All they need is a disposition to avoid the direction where none of their kin can be seen and *viola!* instant snake swarm. Next mix in some [Aligator](https://en.wikipedia.org/wiki/Alligator). > > Alligators consume food that cannot be eaten in one bite by allowing it to rot, or by biting and then spinning or convulsing wildly until bite-sized chunks are torn off. This is referred to as a "death roll". > > > You could easily envision a writhering, convulsing mass of snake-like bodies ripping tiny chunks out of a carcass. The only thing I cannot quite envision is the snake-pack hunting down live animals. It's far too dangerous for non-poisenous reptiles to hunt prey bigger than them. It would require a tremendous combined effort of the pack that probably necessitate a level of intelligence far above what reptiles are capable of. Poisenous snakes, on the other hand, have no reason to hunt together. [Answer] Snakes ingest their prey whole, usually head first. After digestion they usually regurgitate the undigested parts, like horns, hair and the like. They lack the ability of taking chops from a prey. As such it is impossible for a snake to eat a prey from the inside. Moreover, swallowing a creature whole can be done only if it is dead: no matter how weak it is, you don't want it to fight around while halfway down your guts, tearing them open. Additionally, per Nyakouai's comment, a snake which has just swallowed a prey might not be really effective at hunting for a while, so a pack of snakes means one get fed for each prey taken down and is then virtually useless to the pack, so not a great survival tactic as a whole. I have once seen a snake which just had swallowed a chicken egg: the poor beast was so incapable of running away from me with the egg enlarging its body that it preferred regurgitating it, still whole, in order to reach safety. After the whole process it was so exhausted that I could grab it and take it to a safer location. [Answer] Do you REALLY mean pack-hunting, or do you just mean schooling/swarming? [Pack-hunters](https://en.wikipedia.org/wiki/Hagfish) (e.g. Lions, Hyenas, Humans) are intelligent, and cooperative, and voluntarily share the benefits of their kills. They're also almost exclusively apex predators. The only reptiles that do this are crocodiles, and only VERY rarely. **What it sounds like you're describing is really more of a non-aquatic [Hagfish](https://en.wikipedia.org/wiki/Hagfish).** > > ... hagfish can feed upon and often even enter and eviscerate the > bodies of dead and dying/injured sea creatures much larger than > themselves. They are known to devour their prey from the inside.[44] > Hagfish have the ability to absorb dissolved organic matter across the > skin and gill, which may be an adaptation to a scavenging lifestyle, > allowing them to maximize sporadic opportunities for feeding. > > > I can't think of any reason this behavior pattern wouldn't work just as well for a snake as it does for a fish. There are certainly snakes that hunt in swarms, although again not in the cooperative way that defines pack-hunting. (pretty sure a segment from Blue Planet II about these guys is what @Shadowzee was thinking of.) To make a land-dwelling equivalent of this, I think you'd just need to tailor your environment such that there's adequate food sources, and remove the potential competition from mammalian predators. ]
[Question] [ I am investigating the possibility of modifying the speed of light in my world. Assuming that the speed of light in a vacuum can (and in my world, is) modified, what lower bound exists that would permit humanity to exist? --- Everyone has probably heard at least once that some values in Physics must be so precise that it could be compared to [insert absurdly precise example]. [So is Light fine-tuned?](https://en.wikipedia.org/wiki/Fine-tuning) **What would be the lower bound for light speed which still allows Human live?** In following questions I want to address an [upper bound](https://worldbuilding.stackexchange.com/questions/147547/what-is-the-upper-bound-for-lightspeed) and most notable effects. Thanks to many physicists we know that light speed is very important for any part of fundamental Physics (Gravitation, Energy, Relativity, ...) At some light speeds Atoms might have so much energy that 1g of radioactive material would be enough to wipe out all human life. [Answer] The [fine-structure constant](https://en.wikipedia.org/wiki/Fine-structure_constant) is the one controlling most of the properties allowing life as we know to exist. It can be expressed as $\alpha=$$k\_e\cdot e^2 \over \hbar\cdot c$, where * $k\_e$ is the Coulomb constant * $e$ is the elementary charge * $c$ is the speed of light in vacuum * $\hbar$ is Planck constant As you see, if you change $c$ you change $\alpha$, and that would make life impossible. > > The anthropic principle is a controversial argument of why the fine-structure constant has the value it does: stable matter, and therefore life and intelligent beings, could not exist if its value were much different. For instance, were α to change by 4%, stellar fusion would not produce carbon, so that carbon-based life would be impossible. If α were greater than 0.1, stellar fusion would be impossible, and no place in the universe would be warm enough for life as we know it. > > > Therefore > > What would be the lower bound for light speed which still allows Human live? > > > Exactly what it is: $c$ [Answer] From a purely classical point of view, $c = 1 / \sqrt {\varepsilon\_0 \mu\_0}$ which means that if one were to change the speed of ligh $c$ one would have to change $\varepsilon\_0$ (the [vacuum [electric] permittivity](https://en.wikipedia.org/wiki/Vacuum_permittivity)), or $\mu\_0$ (the [vacuum [magnetic] permeability](https://en.wikipedia.org/wiki/Vacuum_permeability)), or both, and, as an immediate effect, change the strength of all electromagnetic phenomena. As it happens, chemistry is first and foremost an electromagnetic phenomenon. In a world with a different speed of light than ours the strength of electromagnetic phenomena is different than in ours and therefore the chemistry works in a different way than in ours. Different chemistry means different life, and, quite obviously, no humans. There may be life in such a world, even intelligent life, but there will most definitely be *no humans*. You cannot have a different speed of light and the same chemistry. You cannot have a different speed of light and human life. [Answer] The fine structure constant was identified as a result of [Michelson and Morley](https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment)'s famous light-measuring experiment. This is the same experiment, whose same incredible results weren't able to be explained away as measurement or process error that caused us to question space and time itself, and ultimately accept that [Lorentz contractions](https://en.wikipedia.org/wiki/Length_contraction#History) are the way the world works. The answer to your question might be the same one : Galilean Relativity (also called Einstein's Relativity). The principle is this: within a local framework, the laws of physics continue always to apply the same way. If the fine structure constant does vary, a similar preserving principle may apply keeping the universe as we know it ticking along just the same. Here are some examples: * Changing $\alpha$ causes the distance between electron orbitals grow tighter ($r = {{\alpha \lambda} \over { 2\pi }}$). Without any other changes, this means that the electromagnetic binding force $F = {{k q\_0 q\_1} \over {r^2}}$ increases. If binding forces become too high, chemistry as we know it falls apart. * But what if the Coulomb constant $k$ contracts with $\alpha$ such that, locally, binding force remains the same irrelevant of the value of the fine structure constant? This outcome is predicted by the math if this relationship holds true : $\alpha$ = ${k e^2}\over{hc}$, but it does require the local speed of light to remain the same. * If space is quantized (required now for quantum gravity and some M theory, but not yet supported by any successful experiment), and if quantized space has any relationship to the fine structure constant, then while the local speed of light remains the same, it is possible that the relative speed of light an outside observer sees increases, while c remains unchanged locally, because you are iterating over smaller chunks of quantum space. To sum up: nobody even knows if the fine structure constant changes. But if it does, it is possible for a principle of relativity to still apply that preserves the universe as we know it locally. That would mean there's no upper (or lower) limit. [Answer] C is the speed of light in a vacuum. Light slows down when passes through transparent media by the factor of the index of refraction. The maximum theoretical refractive index value is $$\infty, which would bring the speed of light to ~0, but ~38 is the highest value engineered into a [meta-material](https://physicsworld.com/a/metamaterial-breaks-refraction-record/). [Answer] Most constants in physics (all that have units, like c, units of speed) cannot be "changed", as you are just renaming the units. The speed of light is the relation between distance and time, so changing speed of light just changes the units of time (and/or distance), but all the physics remains the same. For example, theoretical physicists usually use natural (Plank) units, where c, and most important constants, are exactly 1. A completely different issue is the dimensionless constants, like the fine structure constant, approximately 1/137. These are the units you might want to change in your world if you want different physics. <https://en.wikipedia.org/wiki/Dimensionless_physical_constant> EDIT: Then, if you want to change the speed of light, what you need to change is the dimensionless constants. It will change all the constants with dimensions, or at least their relation. The fine structure constant, for example, is defined as: $$ \alpha = \frac{e^2}{\hbar c \ 4 \pi \varepsilon\_0} $$ and so, $$ c = \frac{e^2}{\hbar \alpha \ 4 \pi \varepsilon\_0} $$ Doubling the the fine structure constant will half the speed of light, while keeping the other constants (e, the charge of the electron [or the proton]; $\hbar$, the Plank's constant; and $\varepsilon\_0$, the permitivitty of free space). Of course, this will change another constants: for example, $c =\frac {1}{\sqrt{\varepsilon\_0 \mu\_0}}$, where $\mu\_0$ is the permeability of free space (related to magnetism). Again, if the fine structure constant is doubled, the relation between the electric and magnetic force will change (magnetism would be 4 time stronger than in our world). The point is that what you have to look is the relation between various forces; changing only a constant with dimensions, like the speed of light, without changing anything else, is only a change of units and so does not change the physics of the world. Answering the initial question, what is the lower bound for lightspeed that permits humanity to exist? None, unless you change a lot of other things. And if you change the dimensionless constants to change the speed of light? A lot of other constants (dimensionless; as said, the constants with dimensions are only relative to the system of units) will change. Which ones? The ratio of the speed of the electron in an orbit to the speed of light will change; the maximun number of protons in an atomic nucleus will change (it is around the inverse of the fine structure constant, 137 in our world; this could give a good limit, because nucleus will be more radioactive; in a world with a fine structure constant double as in our, and so with half the speed of light, palladium [Z=46] would be as radioactive as uranium in our world, Z=92, which would not exist; iodine would be highly radioactive; if $\alpha$ is multiplied by 4, vanadium would be as radioactive as uranium, and if $\alpha$ is multiplied by 8, carbon would be as radioactive as uranium, making life impossible). Then a possible lower limit is about 1/4th (but many changes would have to be made in human chemistry). But in that world stars would not exist, by the way, not as we know them. Citing wikipedia, > > were $\alpha$ to change by 4%, stellar fusion would not produce carbon, so that carbon-based life would be impossible. If α were greater than 0.1, stellar fusion would be impossible, and no place in the universe would be warm enough for life as we know it. > > > You can try to check for other possible changes here: <https://en.wikipedia.org/wiki/Fine-structure_constant#Physical_interpretations>. ]
[Question] [ Now, I am not talking about a golden glow that overtakes the sword itself. I'm not looking for a Lightsaber. I'm talking about a sword that is silver in color giving off a golden reflection (or refraction) from light, whether artificial or natural. No magic, no special technology in the sword itself (i.e. don't use nanobots or gizmos... it just needs to be a regular sword), no voodoo/hoodoo/owo. Just a sword made from existing materials with special finishes and processes if necessary. * An answer is good if it can get this effect. The best answer can do so and still be combat-worthy. **Can a silver-colored sword be designed to reflect a golden light naturally?** [Answer] People like to do stuff like this with their cars. It is called shimmer paint. Here is an example of a silvery white car with gold shimmer treatment. When it catches the light it glows gold. [![glitter gold car](https://i.stack.imgur.com/8aVUY.jpg)](https://i.stack.imgur.com/8aVUY.jpg) These treatments involve small shiny metallic flakes of the desired color. They are not numerous enough to uniformly color the surface, but they are reflective such that in certain light they lend their color (read absorb / reflect light) to the substrate. One could accomplish this with a sword by rolling the gold flake onto it. Some adhesive would help. As I understand they did the car with some sort of film, which probably helps keep the flake oriented correctly. Hopefully this gold glowy sword is not your main monster hacking sword, but more your parade sunset glowy gold make the crowd cheer sword. I worry hacking will take the surface treatment off pretty quick. [Answer] Well, you answered your own question - Silver will reflect a golden light naturally. Just put anything golden up to a mirror. A mirror is silver while the light that bounces from your golden thing will be golden. Silver is not silver. It REFLECTS the part of light that appears to the viewer as silver just as gold reflects the part of the spectrum that appear as gold to the viewer. Silver has very good reflectivity and that's why it appears "white", it bounces almost all light that fall on it, while gold has bad (worse) reflectivity at short wavelengths. That's why it appears yellow (it blocks, colors that have short wavelength while reflecting the ones with longer ones). So just shine any color you want on your silver and it will be appear to be THAT color. [Answer] I would suggest a [Liver of Sulfur patina](http://www.cooltools.us/v/vspfiles/assets/images/article-a_jewelry_artists_guide_to_liver_of_sulfur_patinas.pdf) > > Colors develop one after the other: gold, green, pink, blues, purples, > grays and finally black. If the water is warm or the metal is warm, > the process is greatly speeded up. When you are trying to achieve a > specific color, the cooler the water, the more likely you are to lock > in the color you wanted. The way an item is dipped will also make a > difference. If an item is dipped sideways, the colors will be > streaked. If an item is dipped face down, more vibrant colors will > appear there than on the other side. If an item is turned over and > viewed after dipping, (but before neutralizing) the colors will > continue to develop and often will pool in places, leaving a mottled > appearance. > > > It is a method that is quite simple to use, although it takes a bit of experience to get the desired color correct. The patina is only on the surface, requiring no changes to the actual composition of the sword. A caveat would be in any alloys that are used in the silver to strengthen it, reacting differently to the chemical. To highlight the effect, microgrooves could be made throughout the sword surface. These groves would produce angled surfaces that would reflect light in different directions. If they were concentric, the effect would be to focus them and highlight them when looked at from a particular perspective. Potentially bright flashes of gold color on a silver background. But a digression here - the photons 'reflected' from a surface are NOT the same photons that are incident to it. [The incident photons are absorbed by the material, and re-transmitted](https://www.scientificamerican.com/article/what-is-the-physical-proc/). Usually, this is instantaneous, but the process [can be delayed](https://phys.org/news/2013-07-seconds.html). Also, in some cases such as fluorescence, the incident UV photons are re-transmitted at another frequency. There is no quantum necessity for the re-transmitted photon to be exactly the same as the incident photon, if the substance can either supply energy or absorb energy such that the re-transmitted photon has a [different energy level than the incident photon](https://www.nist.gov/news-events/news/2010/10/little-light-mine-changing-color-single-photons-emitted-quantum-dots). > > "The quantum dot can act as a true single photon source," says > Srinivasan. "Each time we excite the dot, it subsequently releases > that energy as a single photon. In the past, we had little control > over the wavelength of that photon, but now we can generate a single > photon of one color on demand, transmit it over long distances with > fiber optics, and convert it to another color." > > > [Answer] There are two types of reflection - scaterring (paper-like) and specular (mirror like). It is perfectly possible to make something with one colour of scaterring reflection and a different colour of specular reflection, so your sword could look matt silver but reflect light with a golden hue (even if the incident light is white). 1. The sword (made of a good steel) has a roughened surface. For example through some form of [abrasive blasting](https://en.wikipedia.org/wiki/Abrasive_blasting) or [chemical etching](https://en.wikipedia.org/wiki/Chemical_milling). 2. A transparent coating should be applied. This should be optically thick so there are no interference effects between the surface of this coating and the metal underneath. An example might be [physical vapour deposition](https://en.wikipedia.org/wiki/Physical_vapor_deposition) of something like SiO2. This would take a while to get a thick coating, there may be other processes to deposit faster in this case. 3. Now a multilayer [thin film stack](https://en.wikipedia.org/wiki/Dielectric_mirror), for example of alternating TiO2 and SiO2 (both are hard) with thicknesses designed to produce the desired coloured reflection. The outer layers are hard, and the colour of the specular reflection will vary with angle. If you want it to vary less then use higher refractive index layers in the coating (more expensive, might be softer. TiO2 is nice and hard). [Answer] Pretty simple really. The light is golden, it's reflecting something that's golden OR it's NOT just "silver". And I am firmly in the camp of it not being just silver. Because silver as a metal makes a TERRIBLE sword. It is way, way too soft to be an effective sword. Now if you're just talking "silver-colored" like a standard steel sword, Welllll, you just said that it was silver colored. That's like asking how a room painted a color can be...another color. But really, silver isn't a color, it's mainly reflective. You don't say if you want this to be true all the time, or if you want it to be circumstantial. If it's circumstantial, then it can reflect surroundings, the quality of the light at the time. Otherwise you gotta mix in another color/metal. That can change the composition. Now, as to the sword itself--here's a video on how shiny Medieval swords were: <https://www.youtube.com/watch?v=G7ZbbFpschk> Pretty neat. [Answer] Light that travels from a light source, reflects off a blade then reflects off a sheet of white paper to your eye will have the same color as the same light source bouncing off the blade your eye. So changing the color of the source light will change the color of the light you see, but there is no way to make the color bouncing off the page to be different then looking at the blade it's self. BUT there is hope. Depending on context, you may be able to coat it in a Fluorescing material. Calcium, Lead, and Zinc Silicates can all produce a yellow glow when exposed to black lights. You also could mix your silver with titanium or niobium and use anodization to give your silver weapon a golden color. ]
[Question] [ I am currently creating a Spacefaring Race that regularly travels between planetary systems in order to harvest resources, but due to the fact that the conditions required for them to Breed are fairly specific, they must regularly return to their homeworld in order to reproduce, in much the same way Salmon on Earth do. This has been a fairly constant theme throughout their species' evolutionary history, and since they are driven by instinct to return to their birthplace on their own planet they have developed remarkable navigational skills that have served them well as they ventured out into space. However, on their own planet, at least part of their success in accurately navigating complex long-distance migration paths came through their acute sense of smell (Again, much like Salmon). While I do have a means by which they can fairly accurately navigate in space (in addition to Extremely Advanced Spacial Awareness Skills and a natural penchant for gauging the distances/positions/speeds/sizes of Objects, they also have developed Spectroscopic Vision that allows them to use stars of particular compositions as Landmarks or Waypoints), I was wondering if there would be a way for them to incorporate Scent, or if this would have be limited specifically to their exploration of planets and moons. If they *could* somehow sniff the vacuum of space without suffocating... Is there even anything to smell, if there's no air to carry it? What would space even smell like? Could things leave a reliable scent-trail in a vacuum? If not, is there another alternative that they might find similarly intuitive? [Answer] **Most likely not** To simplify smell, a creature is taking in atoms or molecules into a sensor, and those atoms or molecules stimulate the sensor. Searching the web it seems it's generally accepted that there are approximately 100,000 - 1,000,000 atoms per cubic meter in Space. Contrast this with Earth's atmosphere at sea level, which has about 300,000,000,000,000,000,000 atoms per cubic meter (3\*10^22). Which means for every 1 atom in space you'll find 60 quadrillion atoms here on Earth. Your animals' senses of smell would have to be extraordinarily more powerful than any Earth creature's. [Answer] If I wanted to "smell" space I'd use a mass spectrometer with such a long mean free path, smelling would be highly directional with all the limitations that implies (like line of sight) [Answer] Smelling is almost the exact same as tasting with your tongue and they are very closely linked. It happens because particles react with certain cells, and those cells send a signal telling you what you are tasting/smelling. Because it's space, there's almost no particles to interact with. You also can't create a lower-pressure area in your body to attract those particles into your nose. The solution, if you want it, would be to have large sail-like pieces around your body that use their surface area to get enough particles to interact and give you an idea of your surroundings. Using Nex Terrans answer you would need to make it large and travel fast to interact with more volume of space. Since you are traveling interplanetary distances you should be encountering enough particles. Using this article: <https://www.google.com/url?sa=t&source=web&rct=j&url=https://tools.niehs.nih.gov/wetp/Public/DOE_Trainers/13_HANDOUT_SENSE_OF_SMELL.pdf&ved=2ahUKEwjJ1NLS09bfAhUIJVAKHcmVDUQQFjAAegQIAhAB&usg=AOvVaw3BDR52z0714Pyk4lO_U5o9> you can see that some particles can already be smelled at 0.008 parts per million, combine that with traveling through space at interplanetary speeds and you'll be scooping up more than the 3\*10^22 particles per m3 every second to smell. You would have to know the particular (average) composition of particles of different solar systems and solar winds to make sense of them. I'm not saying it's impossible, I'm not saying it's possible, but it's not going to be a very easy or aestetically pleasing thing I think. [Answer] Believe it or not, there are aromatic molecules in space, and these molecules come in a number of fun flavors which vary depending on where you are. [There is a dust cloud near the center of our galaxy that contains ethyl formate, the same chemical that gives raspberries their smell](https://www.theguardian.com/science/2009/apr/21/space-raspberries-amino-acids-astrobiology). Other chemicals found in space include familiar smells like ammonia, hydrogen sulfide, and formaldehyde. Nothing could breathe vacuum, but fortunately breathing and smell don't have to go together. Plenty of Earth animals smell through organs completely unrelated to their breathing tubes, in fact the best sniffers on Earth - moths - smell using their wide, feathery antennae. Space doesn't have a lot of molecules to go around, but I'd expect any space-dwelling creature to have wide solar "sails" to provide it with energy and it's not an altogether bad idea to put some chemosensing organs on the same sails. That being said, smell is probably not a great way of navigating the void. While smells don't need air to carry them (smells are simply gas molecules and gas can spread out through space once it is released) it tends to fade away to nothingness pretty quick unless the smells are created in vast quantities by something like an exploding star. But a spacefaring species that *could* smell in space for whatever reason could very well recognize the scent of its home system. [Answer] **You could have them smell the solar wind.** <https://www.sciencefocus.com/space/what-is-the-solar-wind-made-of/> > > The solar wind is a stream of energetic particles ejected by the Sun. > These include electrons and protons from hydrogen, along with atomic > nuclei like helium, otherwise known as alpha particles. > > > There are also traces of ‘heavy ions’ and atomic nuclei of carbon, > nitrogen, oxygen, neon and magnesium. Recent missions have even > detected tiny amounts of potassium, titanium and nickel. > > > Probably the solar wind produced by each star is characteristic of that star. Maybe just as salmon can taste their own home stream even far out at sea, your creatures can taste the particular components of their home star even far away in space. Of course this wind is made of charged particles moving very fast through the vacuum - but they are particles, not electromagnetic radiation or vibrations, and so smell or taste would be the most relevant sensory modality. [Answer] There's a YT video of a former space station astronaut. Amongst the things he discusses is what he believes is the "smell" of outer space. Basically he said if you broke seal in the airlock before the space properly re-pressurized, you would smell "slightly burned meat." He explains why he thinks that odor is detected. <https://www.youtube.com/watch?v=t6rHHnABoT8> ]
[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/119186/edit). Closed 5 years ago. [Improve this question](/posts/119186/edit) ## tl;dr The typical fantasy setting is just Earth with "magic" tacked on to let the wizards cheat nature. There is absolutely no attempt to integrate magic with nature. Trees, lightning, birds and so forth run on real science, but magic is its own self-contained thing that never really interacts with nature except to make possible things considered impossible in reality. I recommend the article "[Breaking out of Scientific Magic Systems](http://www.darkshire.net/jhkim/rpg/magic/antiscience.html)" for an excellent breakdown of this problem. The article is specific to RPGs but the basic gist is applicable to fantasy genre as whole (especially that inspired by RPGs). While a great article, I have been unable to find any more detailed guides for building a rational magical/natural physics system since the assumption that "fantasy settings run on real physics with magic tacked on" is so pervasive. **What can I do to adjudicate a rational set of physical rules that treats magic as part of nature? What pitfalls should I look out for? Are there helpful examples I can look at? Etc.** ## Examples specific to RPGs RPGs like D&D are massive offenders. Magic is not simply excessively systematized for practical usage by players, but treated fundamentally separate from nature even though that is not remotely necessary for play. * There are effects like "detect magic" and "anti-magic" which only affect things considered magic without affecting anything non-magic. * Any animals which do not exist on Earth are considered magical and unnatural, even though that makes no sense since Earth doesn't exist in the fantasy world. For example, a giant ant that spits acid is considered a "magical beast" or "monstrosity" despite having nothing paranormal about it if it was seen in reality. * Magic is considered transient and even simple effects like "speak with animals" are given very precise time limits. * Crafting magical swords involves a wizard adding a property of magic-ness to a normal sword and the aforementioned anti-magic would turn render said sword non-magical without otherwise reducing its effectiveness. ## Example: Classical elements versus periodic elements For another example, a typical fantasy setting has elemental beings composed of the four classical elements, yet this is only relevant to elemental beings since the rest of the universe is composed of the elements on the periodic table. This despite the fact that alchemical traditions that gave rise to the concept of elemental beings were based on the assumption that the universe really was composed of the four classical elements. For a specific example in fiction, the anime *No Game No Life* at one point has a character win a game by taking advantage of the fact that an opponent with encyclopedic knowledge of magic is completely ignorant of atomic theory. ## Why this sticks out and how pre-modern fantasy was different This makes absolutely no sense to me. Whether the universe is the result of order spontaneously arising from chaos or intelligent design, if magic has always existed then it should be just as fundamental to existence as any other fundamental force. It should not be possible to say something is magical or non-magical any more than you can say something does or does not contain electrons, or to have two completely different sets of classical and periodic elements that only apply to magic or non-magic matter respectively. It feels to me like writers who grew up in modern times are projecting their knowledge of the modern world onto fantasy concepts without understanding the originating pre-modern context. You see the unification of magic and nature all the time in mythology, fairy tales and folklore. Magic is omnipresent in these stories even for non-wizards. Perfectly ordinary people who are not designated as wizards are able to perform feats we would consider magic, like talk to trees or place curses with their dying breath or come back from the dead. Much of the time this happens without their conscious consent or knowledge. (Cross-reference magical thinking in anthropology studies.) You could even say that nature is depicted as running on magical rules. Meanwhile, most modern writing seems to treat magic solely as a means for wizards to cheat physics and do cool stuff rather than a basic part of nature. ## What are the ramifications of fantasy physics? Using this conceit in world building requires thinking about magic in a completely different way. Rather than the purview of reality-warping wizards, magic becomes something that makes the fantasy world fundamentally different from reality. The fantasy reality is reactive, alive and sentient in some way. The physics of the fantasy world are different and allow things impossible in reality. Conversely, this means that things possible in reality may not be possible in the fantasy world because the supporting physics do not exist. In reality we can build electronics because our physics allow that, but do the physics of the fantasy world even have atoms? If the classical elements of earth and fire and air and water and quintessence are real physical constants, then clearly atomic theory is wrong on that world. Are diseases caused by viruses and bacteria, or by evil spirits and imbalances of the humors? Is gravity a physical manifestation of the emotion love? These sorts of questions and their answers have huge ramifications on how the fantasy world works. [Answer] **Evolution** Simply put, magic should be present on every part of the natural realm, it must be as common to see a bird using arcane currents to produce a lightning bolt as it is for us to see birds banking in thermal currents to gain altitude. These animals will have evolved in a world full of magic and so they will have evolved to make use of it, even the most common animals like cats and dogs should have some measure of magical abilities. Even your plants will probably be able to use and store mana in some way. **Food Web** One of the biggest problems in fantasy is the food chain, if you have a giant Wyvern on the forest, where are the prey animals they feed on? What kind of prey would have required the Wyverns to have evolved such a powerful venon and flight? Most RPG bestiaries are usually concerned only about the big and flashy predators of the world, most of the time living in complete isolation. There are no food chain going around, almost no prey species to fill the niches. [Answer] It seems like you're trying to come at magic from a first-principles perspective – which, bravo for thinking big! If I'm understanding you correctly, you want to know how you can set up a magical system that has had magical influence in the development of the world, if not the universe itself. **The laws of nature** First: there is a limit to this thinking, and the limit is pretty mundane. Since we, in the real world, don't actually know everything about how the universe works, it's nigh impossible to say how changing the fundamental equations to allow some form of magic would affect everything. Like, if General Relativity is optional, what does that say about Noether's Theorem? If gauge symmetry doesn't mean conserved quantities, then your universe cannot work on the principle of least action (because math). If it doesn't, what are the principles it does run on? What are the consequences of those principles, and are you willing to spend decades dealing with tensor calculus to figure it out? On the other hand, if you introduce a new physical force, let's call it 'magic,' say, then how does that interact with electricity? The strong and weak force? How does it fit into the standard model? Does it have a boson? We barely understand how these things work in real life, so how can you invent a system that appropriately incorporates *additional complexity*? At some point, your physics *has* to reduce to the normal stuff, otherwise your world will simply be *too foreign*, as in, there won't be any planets, or light, or time. So if you want to have a magical world that's interesting to read about, you have to 'tack on' magic haphazardly somewhere – the question is where, and I think that's something we can work with to help overcome your frustration. **The sweet spot** I, too, have sometimes felt like in some fantasy worlds they expect us to believe everything developed just about the same as the real world – except magic. That goes for everything from societal power structures to evolution. **I think the key to resolving your frustration is deciding what you want to cause magic** – and having it be more closely connected to advent of living beings. Some options: * Is it that the gods created this world like a computer program and wizards are just altering the code? Then you can do like @TheAverageCanadian suggests (which is super cool!) and make an ancient language that controls reality. (Maybe you could challenge assumptions that the language is spoken – who says the gods were human-like? Tons of intriguing possibilities here!) * Is it that living things give off a magic field? Then you can do things like what @Sasha suggested and have animals with magical powers as well. This could also address your question about sickness and bacteria: perhaps microbes give off a field that interferes with our own. * Is it a specific element that gives off magic? Then you could localize the affects in the last paragraph to specific areas, which could be tons of fun and allow for a world pretty similar to ours – except some places, where it gets super weird. Other questions to answer when you've decided what causes magic: * Is magic a strong influence on reality or weak? * How long do magical effects last? How far do they reach? (Is this a reverse square law deal, or is it a substance that decays?) * When did living things develop the ability to use magic? How did that affect human evolution? How did animals evolve in response? * Is magic a finite quantity? Can it be grown or manufactured? * Who/What has access to it? What determines how much magic something has? * Are there certain laws of nature it affects and others it doesn't? Why or why not? Really, the choices are all yours! Sometimes it's neat just to pick something and see where it leads you. But at the core, if you want to take this approach, you need to figure out what you want to be the cause of magic. Following the logical chain of consequences from that one decision can lead to a relatively consistent world with many, many intricate layers that will be fun for the reader to unravel. Just **don't try to go too far back**, or nestle magic too deep in physical laws – our universe is an incredibly delicate balance, and trying to incorporate magic too fundamentally is leading a bull into a china shop. Figuring out the consequences of that would require a far better understanding of the current universe than we currently have, and would probably require the invention of several new fields of mathematics. [Answer] One of my favorite interpretations of "Magic" is thus: The universe that we know has a sort of "language" far above our own understanding. When a human (or animal, or other creature, your choice) speaks in that ancient language, the universe has no choice but to obey the will of the speaker. This is similar in nature to the concept of a "true name", where everyone has a name given by the universe, and anyone who learns that name has total control over the person. If you frame the elements of life typically thought as "inanimate" as if they were alive, then this makes sense. Most beings do not know how to speak the language of the universe, so the don't have "magic". Basically, I would frame every atom of this universe as living, and the art of magic is simply figuring out how to speak to the universe and convince it to do what you want. This way, you can explain the normal effects of these things, what we consider to be "the laws of the universe", to be their own free will, which can be affected given the right methods. [Answer] My all-time favourite system for Magic that is as scientific and systematic as it can be, with costs and balances has got to be the magic system from Eragon and the rest of the series. If you haven't read it I would highly recommend it. The way it works, summarized shortly is: * Magic is Innate and is somehow linked to your brain, somewhat like Telekinesis. * You direct your "magic" with your thoughts and the magic interprets what you're trying to do with it. You direct the flow of energy towards a certain task, and the energy does it to the best of its ability. The "magic" is often funneled through the use of a so-called "ancient language" that can focus the user and prevent their thoughts from straying. The more specific they are with the language, the lesser the chance of something going wrong. * The amount of energy required to perform a certain piece of magic is the same amount as it would take to accomplish that task without magic. This cost increases exponentially as the distance increases. * The "energy" that powers the magic is the same energy that powers the magic-user's body. The more energy you use, the more tired you become. Use too much energy and you will die. * Combining both previous points, if you were to try to move a rock with magic, after you moved it you would feel as tired as if you had just moved it with your arms and legs. The further the rock is away from you, the more energy it requires. If you push yourself too far and dump too much energy into it, you will use up all of your energy contained in your body and die. * The Eragon system also has a system of people's minds interacting and powerful casters can break into the minds of others if they don't protect themselves. It's fairly complicated, I won't get into it. Read the books! The key highlights to this system are: * The law of physics and thermodynamics apply. Energy is never created nor is it ever destroyed. * Magic users are not omnipotent, they are limited by the amount of energy in their body (although powerful magic users can transfer energy from themselves or others into gems to be used later). * The system keeps a sort of "reality check" on the typical magic systems that hand-wave away a lot of physics and etc. * The system of mental interaction, reading minds & etc is really cool. There's a lot of nuance to this system that I can't go into without going on for pages and pages, but this should give you the general idea. I would highly recommend reading the books, I can't say that enough! [Answer] A very nice concept of magic I encounteted in a book once was based on the energetically linking of objects. The link is established by the thoughts of the magician. Everyone can use magic to the extend of their concentration. Professional magicians basicly train to concentrate on one or several thoughts without their concentration wavering. The link follows a principle of similarity. The easiest trick is to break a branch, magically link both pieces and let one fly by moving the other. Equally simple links are those between similar objects (like coins). If you want to accomplish a powerfull magical link, you have to find an object that shares some similarity with the object you want to influence. One example given in the book was causing a natural lightning to strike a tree by linking several metallic objects to the tree (since electricity runs easier through metal than through wood). Or think of Voodoo... The cost of magic is your life energy, more specifically the chemical and thermal energy stored in your body. Like thinking, magic uses your natural energy. Using too much magic would cause "casters frost" and extreme hunger by depleting the magic user of their thermal energy. The energy required to establish a magical link increases with the distance of both objects and with the diffetences between both objects. Some examples of increasing energy consumption for magic: * two pieces of the same object * two objects of the same kind * two objects of the same material * one objects of a material and a piece of the raw material * objects of the same material but in different aggregation states * two objects of similar, but different materials, like an iron nail and a copper tube * objects of diffetent materials One link can only be established between 2 objects. To include more objects, you would have to concentrate on several links at the same time - an extremely difficult task that only trained magicians can perform. ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- This question does not appear to be about **worldbuilding**, within the scope defined in the [help center](https://worldbuilding.stackexchange.com/help). Closed 5 years ago. [Improve this question](/posts/117628/edit) Mythology is replete with examples of people selling their soul to the devil. Except... how does that actually work, mechanically? Let's say you sign a contract agreeing that the devil may take your soul. How does it get transferred to him? If he has the power to take it himself, he wouldn't need a contract. So maybe it's something you do, like how when you sell someone your car you have to physically hand them they keys. I don't know about you, but I wouldn't have the first clue how to go about handing someone my soul. If it's not the devil that removes it, and it's not the contractor, that means there must be some third party. An external agency, that manages and administers the soul contracts, ensuring that the deal is fulfilled, and transferring the soul to the recipient. A neutral party, that can be trusted not to cheat, and is not interested in taking the soul for themselves. Possibly an individual, possibly an agency, but there's got to be someone. So, who does this? And what do they get out of it? Edit: Apparently I need to be more specific with what I am asking Premise: 1. Assume that it is possible for a human to sell their soul to a supernatural being. 2. Supernatural beings interested in acquiring souls are not able to take them by force, and humans cannot transfer souls without assistance. 3. Therefore some other supernatural being (or organization of such) mediates soul-transfers, and enforces such contracts (i.e. rules whether the terms are met and the soul transfer goes ahead). Question: 1. What is the identity of this being(s)? 2. Why do they do this? How do they benefit from assisting in the transfer of souls? So, although additional details are certainly welcome, a basic answer might look like "soul exchanges are mediated by [NAME], who do it because [REASON]". The best answer is the one that requires the least changes from standard mythology. That is, as much as possible using existing mythological beings, with an explanation that is similar to their myths/domain, rather than postulating an entire new cast or ascribing out of character motivations. Apologies to whoever this was not clear to. [Answer] **God, of course.** Since we speak of soul and devil, we think it is safe to assume one of the Abrahamic religions in any of its variants. So: * God is all-powerful, and * God has given men free will. Which means that if a man decides to relinquish his soul to the devil, then God just obliges and performs the exchange himself out of respect to the man's will and the rules He established. Yes, God is not preventing the man from getting eternal punishment for this, but God is not preventing other men from getting eternal punishment for other sins that they commit and that God could stop as easily as this transaction. [Answer] Consider that the devil does indeed have the power to take a soul, but humans have the ability to keep their soul. All it would take for the devil to take the human soul is for the human to not resist. Most humans, however, innately hold onto their souls by some instinct. Presumably, humans don't have the innate knowledge of how to release their hold, so the devil, in his malign wisdom, has them sign a contract as a sort of aid to teach them how to release their grip. By succumbing to his will through the ritual of signing the contract, they release their hold, and the devil can take the soul. Or, if you want a more magical approach, the ritual of signing the contract brings the human's will/spirit into contact with the devil's will/spirit, creating a link of contagion between them. This link is what the devil uses to magically seize the human's soul. Since the contract is also the contagious link between then, the devil is required to fulfill the contract's terms, or risk the link being severed and the soul returning to its human host. [Answer] **The *agreement itself* handles the transfer** Literature is replete with authors proposing rules that the devil must be subject to --even if we mere mortals don't understand those rules-- to get around the fundamental question most children figure out around age seven ("why hasn't the devil *already* conquered the world?"). The mechanics of soul transfer are governed by the same mortals-don't-need-to-understand rules. The *agreement itself* is the binding supernatural action, no further arbitration or action is needed. There are several forms of *appeal* to the transfer (most notably contests, trials, and occasionally marriages). In trials, the *ruling itself* is typically sufficient to instantly negate the transfer, indicating that the same rules-we-don't-understand still apply, and that the words themselves have the supernatural power. Best example of both immediate transfer and immediate nullification: [The Simpsons Treehouse of Horror IV](http://simpsons.wikia.com/wiki/Treehouse_of_Horror_IV), in which Homer sells his soul for a donut, but the transaction is appealed and successfully reversed at trial upon presentation of a prior claim upon the soul. [Answer] Every soul has an *Ownership History* section that resembles what you would see on a vehicle title. Here is an example: 1. Owner: ~~God~~ 2. Owner: ~~Jimmy~~ -- signed: God 3. Owner: ~~Satan~~ -- signed: Jimmy & Satan 4. Owner: The Goldman Sachs Group, Inc. -- signed Satan & Lloyd Blankfein, CEO 5. Owner: The soul itself prevents entries from being added that do not include the signature of the owner at that time. Not everybody can write to (or even see) this section, which significantly limits the number of potential future buyers for Jimmy's soul. Also, souls come equipped with autonomous navigation capabilities which cause the soul travel to whoever occupies the final name in the list whenever its body dies. So to answer your question, it is the soul that automatically completes the agreement. In order to make transactions more accessible to mortals, it has been proposed that the final line on each soul could be copied into the Ethereum blockchain and then entities like Goldman Sachs could further transfer Jimmy's soul via smart contracts--but updating the soul auto-navigation system to connect to the Ethereum network upon death has proved technically challenging so far. ]
[Question] [ **Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers. --- You are asking questions about a story set in a world instead of about building a world. For more information, see [Why is my question "Too Story Based" and how do I get it opened?](https://worldbuilding.meta.stackexchange.com/q/3300/49). Closed 5 years ago. [Improve this question](/posts/111556/edit) I'm writing a story about foreign policy student who needs to do an internship in his final year. And while his peers apply at think-tanks and government agencies, he has low grades and no connections. Destiny interferes and he manages to get an internship in a government of fictional MENA dictator who is more than 3 decades in power and managed to play different great powers against each other and stay independent. His country is located on an important strait, through which large percentage of world trade passes through. Is it possible for such person to operate just on instinct, without knowing anything about the international relations theory? The meat of my story is comparing the student who knows things by the book. And the dictator who experienced all those things on his skin. Theorist vs practitioner. [Answer] ## In theory, practice and theory are the same thing. In practice, they're totally different. It's important to not confuse book learning with actual skill. If this hapless intern of yours is actually a really cunning negotiator and has excellent fingertip feel for political opportunities then he'll likely do well in a dictatorship. Those two skills can't be taught in school and even if they could, the skills would be bound up in academic theory. This applies to the dictator too. In professions with long apprenticeships, it's impossible to write down everything there is to know. It can only be learned by experience. This dictator may have learned his skill from experience. Even if he wanted to, he may not be able to convey what he knows. Just because information can't be spoken or written, doesn't make it less real or less valuable. In many cases, it is far more valuable than mere book learning. Might I recommend the [Gervais Principle](https://www.ribbonfarm.com/the-gervais-principle/) for an incredibly interesting read on the power dynamics in organizations. [Answer] He has control of something very valuable. If nobody is willing or able to take it from him by force he can blunder all he wants for a long time and people will call it clever because insulting powerful people is exactly what diplomacy isn't. A person with a reputation for winning (as one might expect from a dictator who isn't dead yet) can afford to make silly moves sometimes simply because other people worry that it might be some sort of trap. A lot of foreign relations are simpler for a dictator than a scientist, since the dictator can use the final argument of kings to prove their theories, can run direct experiments, and gets inside access to the true preferences and motivations of an important actor. Foreign policy theory is more or less academics watching players, and then guessing why things (didn't) work. They come up with some very well thought through ideas and learn their history very well, but there is very little experimentation, and no controlled repeatability. [Answer] Of course. Plenty of "great dictators" were and are idiots. And him "playing the other powers" might mean "the great powers playing each other" combined with some blind luck and decent social skills. He just needs aides who can hash out any details, and what is a dictator without his own Penultimo? [Answer] Sure. Lots of jobs can be learned "on the job" through mentoring and trial and error. Might even be pretty good at it if they are an intuitive person who's good at reading people. That's not really something they can teach in school, but it's pretty important to know for successful international relations. The schooling might help some people, but there will still be things to learn afterward just because you're dealing with real people, not theory. [Answer] If the dictator has been ruling his country for more than 30 years without losing his sovereignty, it shows they have done a good job(Keeping other great powers from overturning his dictatorship and losing control over the strait). With time the experience they gained over time would shape to form the theory gained by the intern. In fact theory is based on the experience gained by other people in the field. So I think there would not be much of conflict between the two . [Answer] Often times, in strategic pursuits(such as international political theory), strategy gets "exalted" to a "school of thought". While such strategies were incredibly valid within the limited confines of their targeted contexts, they are of only limited success as a school of thought, producing blindspots, and rejecting valid strategies that run counter to the exalted one. This is an issue that's more prevalent in Academia than it is in the school of Hard-Knocks because the former's *GOAL* is to find and codify a legitimate School of Thought to work with. At least among the elites of the two institutions. Having your Dictator constantly correct the student with "Context is everything" or "Ah, usually, that is true, but I happen to know that....". These sorts of corrections keep the student's previous studies as "valid", but reduce their broad applicability. ]
[Question] [ In the game mass effect the Asari are an alien species...no one truly knows their shape and real form, but they do apear as sexy females to many other species, humans included. The asari can reproduce with most life forms thats why they have this illusory tactic , which seems impossible. So, Instead I'm going to ask what else could drive any life form to evolve complete illusion abilities? By real illusion I exclude chamaleons and octopus as they can only change color and "act". And it doesn't have to be shapeshifting. Think more along the lines of induced and controlled visive hallucinations or something like that. [Answer] Others have covered the 'why', with Asari being brood parasites for sentient beings, but perhaps some idea of 'how' might be useful. As @Kevin points out, the illusory effect is present even in pictures of Asari. This would rule out any sort of shape-shifting or pheromone production from the Asari at the point of viewing. However, there's a very interesting parasite called Toxoplasma gondii which reproduces in the digestive tract of cats. When it infects other animals (like rats, mice or even humans), it manipulates their brain chemistry to like cats (presumably find their smell attractive, can't find more detail). If asari have a similar infectious mechanism which alters a host's brain chemistry to find asari attractive, this would mean that any infected sentient would see a picture of an asari and find them attractive. Creepy. Edit: I've had some thoughts as to how this mechanism might have evolved. From our current experience, people seem to make the assumption that each planet hosts one sentient human-analogue species. However, if you look back at our evolutionary history, only a very brief period have we spent it alone. Throughout the vast majority we have shared it with other, competing hominin species. This would likely be true of prehistoric asari. So, perhaps this brood-parasitic mechanism evolved as a method of competing with rival prehistoric asari species, which would provide a significant advantage. Roll forwards to the present day, and the brood-parasitic asari species have wholly outcompeted the non-brood-parasitic species. [Answer] **Nest parasites.** <https://www.nytimes.com/2015/07/21/science/ant-nest-beetles-social-parasites-mimicry.html> > > But some invaders manage to slip in with ease, none more mystifyingly > than the ant nest beetle. > > > Adult beetles stride into an ant colony in search of a mate, without > being harassed. They lay eggs, from which larva hatch. As far as > scientists can tell, workers feed the young beetles as if they were > ants. > > > When the beetles grow into adults, the ants swarm around them, > grooming their bodies. In exchange for this hospitality, the beetles > sink their jaws into ant larvae and freshly moulted adults in order to > drink their body fluids. > > > Social organisms are superentities. Where they exist they dominate. A good evolutionary strategy for an creature which is not of the social organism's species is to ingratiate itself into the society of the social organism, benefitting from its protection and resources. This is what the Asari do. **They are nest parasites of intelligent social species**. Their "attractiveness" is interpreted as sexual by humans but is something more primal - it is an induced perception of desirability or charisma which makes members of social species feel like the Asari individual should be a valued part of the society or family or mate group. Much in the way the ant nest beetles are perceived by the ants. Social insects are bound together with sound and smell cues. For intelligent social species (which would be all spacefaring species) it would not be surprising that the neural mechanisms which hold together social species might have evolved convergently, and so all be susceptible to the same mechanisms the Asari evolved to trick the social species they evolved with on their homeward. The prediction: intelligent asocial creatures (a rarity I would think) would be immune to the Asari. But synthetic social species might not. --- The question - why would Asari reproduce in the company of a member of the social species? If a member of the parasitized social species accepts the Asari as a mate, that means he or she has been well and truly tricked. The hustle is effective and that Asari individual is safely ensconced in a social nest. Resources and protection will therefore be available to the next generation as well, and with those things ensured it is a good time to reproduce. [Answer] **They are Actually Reproductive Parasites** The Asari in Mass Effect have adapted to project some sort of influence over other species that makes them sexually attractive to members of other species. For instance, in a cantina you can over-hear a conversation between a human, a turian, and a salarian. They all find different aspects of the asari stripper attractive, which becomes even more odd when the salarian agrees since *salarians don't have a libido!* When an Asari reproduces her daughter contains none of the genetic information from the father, the Asari physiology simply uses the other partner's genetic code to randomize her own (through some sort of physiological hand-wavium). It is suggested in this overheard conversation that maybe she is using pheromones of some sort or possibly telepathic manipulation. So what does this mean? I think Asari are actually physically adapted to breed out competing species, kind of like how the Cuckoo will lay an egg in another bird species nest that will hatch, kill the other chicks, and then be raised by the other species parents. The Asari live for 1,000 years, if they only even have a kid every 10 years after age 80 that's still 92 children. Lets say each partner they have is a member of the opposite species who never has a child of their own. That is 92 partners from another species that *never actually sucessfully produced offspring.* This is only if they mate every decade, they seem to be physically capable of pumping out 4 to 5 times more children over a life time. each of those children does the same, and each of their grand children do the same etc etc. You quickly have tens of thousands of Asari born and tens of thousands of alien partners who never actually sucessfully mated, thus meaning that tens of thousands of their own species were never born. Worse, like the Cuckoo, the asari children are supported and raised by the alien parents effort and resources. perhaps not only do Asari adults exude pheromones and utilize telepathy to manipulate affection from their victim, but the child does so as well on the parent. The parent is blissfully unaware that they are helping a competing species reproduce while not passing any of their own genetic material on to better their own species. I'm not saying Asari are actively trying to wipe out competing species, its even possible that they aren't actually consciously aware of this evolutionary trait. It could simply be a way that they evolved to crowd out competition that they have no actual control over. The Asari already conceal the fact from the galaxy that a small percentage of their population are not only lethal to mate with, but actually become more powerful and more addicted to the act every time they do so. It is not a big stretch to think that maybe they are also concealing the fact that their races promiscuity and willingness to mate with other species is actually a hardwired evolutionary trait to reduce foreign populations and increase their own. On a long enough time-line they could potentially end up out breeding and rendering all competing races extinct or at least vastly outnumbered, especially since a 1000 year long lifespan means that potentially thousands of members of different generations of the same lineage may all be alive at the same time. ]
[Question] [ Is there any restrictions to have a world where humans gain energy by photosynthesis? [Answer] You would need to make it worth their while. Photosynthesis is not all that powerful. It's roughly [3-6% efficient](https://en.wikipedia.org/wiki/Photosynthetic_efficiency). The [human skin](https://en.wikipedia.org/wiki/Human_skin) is roughly 2 square meters in area. If we pretend that *all* of it is covering the ground like a solar panel, we could pretend we could consume the energy from 2 square meters of area (obviously this is a massive overestimation). Each square meter of the Earth near the equator [receives](https://en.wikipedia.org/wiki/Orders_of_magnitude_(energy)) 1.4kW of sunlight. Combining those numbers, photosynthesis could produce 84-168W. Assuming roughly 6 hours of peak sunlight (this is the estimation they use when specing solar panels to a house's consumption), that's on the order of 2000kJ. Humans consume 2000 Calories a day, which is 8368kJ. That means our photosynthesis could produce 25% of our energy intake. And that was with *terribly* aggressive overestimates on how much production we could make. You'll never get all 2 square meters perfectly lit by the sun. So how could we make this work? Well, we could give them a brighter star. Let's say there's roughly 2x higher [solar constant](https://en.wikipedia.org/wiki/Solar_constant): 3.0kW/m^2. And instead of using photosynthesis, at its 3-6% efficiency, let's use the latest and greatest residential [photovoltaic](https://en.wikipedia.org/wiki/Photovoltaics) cells at 22%. 8368kJ/day is roughly 1400kJ/peak hour, or 388W. With 22% efficient cells and 3.0kW/m^2 solar flux, that would take about half a square meter of surface area. That's starting to get manageable. [Answer] [There are (at least) four species that we know of that actually photosynthesize for energy](https://umich.uloop.com/news/view.php/77109/4-incredible-photosynthetic-animals) **Sea Slugs** borrow genes from the algae that they eat through horizontal genetic transfer, and incorporate them into their own cells. These cells are so efficient that the sea slug can live up to 9 months without eating. The **Spotted Salamander** has a symbiotic relationship with algae cells. The chloroplasts were found near the mitochondria within the salamander’s cells, meaning that the mitochondria were likely directly consuming the oxygen and carbohydrates that are created through photosynthesis. The **Oriental Hornet** works a little differently. Instead of chloroplasts, its yellow band contains xanthoperin, which absorbs sunlight and builds up an electric charge that could be conducted through the cuticle of its exoskeleton, as well as through silk surrounding the hornet pupae and the colony’s comb walls. This voltage is released as current when the hornet is in darkness, and seems to be important for the development of the hornet pupae. The **Pea Aphid** uses carotenoids instead of chloroplasts. Darker aphids had more carotenoids, and higher levels of adenosine triphosphate (ATP, or energy) than lighter aphids. While more research is necessary to be sure that aphids really have photosynthetic abilities, it is clear that carotenoids can absorb light and pass that energy on to the aphids. Now for the main question, could this ability be given to a human? Since it is known that the spotted salamander is able to maintain a symbiotic relationship with algae and is able to get energy from it, it's not out of the question that CRISPR or something similar could be used to make sure that the body doesn't attack the algae cells, or even integrate the specific DNA directly like the sea slug. It would mainly be useful in the skin cells, as that's the part of the body that receives light. If carotenoids are used instead of chloroplasts then you could end up with skin that is white and orange along with green, though the darker colors give more energy. You couldn't live on it solely, but it could help supplement the energy received from food. [Answer] There is nothing that expressly prevents this in biology, save efficiency. While green Photosynthesis is 5% efficient, Black is 12%. On the other hand, Photovoltaics produce closer to 23%. Skin with chlorophyll will be significantly stiffer than normal, but the same is true with scales, so if you want to use plant-people they need to map the stiffness based on necessary flexibility (not the inside of the elbow etc.) Photovoltaics don't arise naturally, however, it is biocompatible, and doesn't need to be ex-macana added. There arises a need for an engineer for that. THIS WILL BE SUPPLEMENTAL and not be your primary diet. Those you use this method may be nocturnal and lock into position to sleep (this is very prevalent in the animal kingdom) This could also be a mechanism to directly supply O2 and cellulose sugar into the bloodstream, allowing for a solution to a host of blood-oxygen and blood-sugar related problems; These being everything from Type 1 diabetes to altitude sickness and co2 poisoning (a MAJOR barrier to space travel, Morso than heat and oxygen supply) ***EDIT*** At **100%** the Photovoltaic skin could produce 0.6 watts per inch. at that rate fruits and small organisms could supplement the body completely. (mostly for the vitamins and minerals, not energy) Humans do not need or generate much power. If a person consumes 2000 calories in a day; And every calorie from food defined as 4200 joules of energy. Used over the course of a day (86,400 seconds), this person uses an average of 97.2 joules a second, meaning they have an average power of 97.2 watts. Thus needing less than a square foot of skin to use this method. [Answer] Assuming plants maintain their relative levels of efficiency in photosynthesis, a human, as noted, simply does not have the surface area to support enough photosynthesis to really matter. Needing @ an acre of surface area to support a single human is somewhat impractical, unless we change venues: Space A human/plant symbiont with an acre of surface area could exist in free fall. The plant part would absorb sunlight and the waste products of the human part, and the human part would receive sugars, starches and O2 in return, essentially creating a small closed ecosystem. [![enter image description here](https://i.stack.imgur.com/YCSAv.jpg)](https://i.stack.imgur.com/YCSAv.jpg) *Hyperplant/human organism in orbit* The plant would have to be drastically modified, needing some sort of waxy coating to seal in the water and gasses from the vacuum, and likely light and dark surfaces to act as solar sails, as well as some sort of musculature to orient the "leaves". the human part would have the roots of the plant embedded in most of the body, with some of the roots absorbing the waste products while others deliver the plant's "waste" products. Like everything else, there would be evolutionary adaptations (much larger, more elaborate plants in deep space where sunlight is more limited, for example), and the organism would have to land on NEO's or asteroids from time to time in order to "top up" water and elements which have been lost due to inefficiencies of the system. So using photosynthesis with a human is possible, so long as you change the parameters to make it fit the environment. [Answer] Directly yes, we don't photosynthesise, so they wouldn't be human if they did. Indirectly, no, we already derive energy from it we're at the top of a food chain where the bottom photosynthesises. [Answer] We've been getting energy from photosynthesis for millennia. We call it *farming*. Almost every form of energy, from fossil fuels to hydroelectric has, at its source, the Sun. The only methods that don't rely on the sun are geothermal and fission. ]
[Question] [ I have a race of very non-humanoid aliens, let's call them Zoblings, and they find an English Dictionary. These aliens are being oppressed and exploited as a resource by the humans because they don't realise they are dealing with intelligent creatures. During a raid the Zoblings find an English Dictionary. Given that they can recognise that these symbols have meaning to the Humans, could they learn to at least write in English without the aid of a human? [Answer] Given that you can recognize that these symbols have meaning to the Egyptians, can you learn to at least write in it without the aid on an Egyptian? [![Egyptian Hieroglyphs](https://i.stack.imgur.com/reuJc.jpg)](https://i.stack.imgur.com/reuJc.jpg) The above could be a dictionary or a grocery list, there is no difference to you. The Zoblings are going to have the same problem we had when trying to understand the Egyptian hieroglyphics. We were only able to understand these hieroglyphs when we found the Rosetta Stone, since we then had a reference for what the symbols *mean*, not just what set of symbols they had. It's not even enough to hear the humans speak, since the Zoblings will have no way to understand how any letter is pronounced and thus can't match spoken words to the written words. Unless the Zoblings can get a human to give examples to words in the dictionary or find some translation of a few words into the Zobling's language, they won't be able to decipher the meaning of what the weird symbols in the dictionary are. However, if the end goal is just proving that the Zoblings are intelligent, then they have better options: mimicking humans sounds/actions to show they understand human are doing *something*, coordinating themselves to perform some patterns like tapping their feet a certain number of times over and over again until the humans pay attention, etc. [Answer] I'm assuming that by "learning to write in English" you mean actually writing meaningful texts in English, rather than just copying out words without any idea of their meaning. In order to do this, the Zoblings must be able to hear the humans speak, to parse their speech somehow, and to match it with texts, so I guess they must catch humans in the act of reading aloud from a text that the Zoblings can get a hold of, or at least see. This is no mean feat. I mean, would you manage to learn how to write in a language you know nothing about, written in an unknown alphabet, just by looking over the shoulders of people as they (for some reason) read aloud from a text? The dictionary is a mere detail. It would give the Zoblings the chance to study the alphabet, punctuation rules, etc. But unless the Zoblings can force a human to read aloud from the dictionary in their presence, they don't actually need it. At the stage where a monolingual dictionary is useful for comprehending a language, you must already know *a lot* about the language in the first place. Your best bet is to have the Zoblings learn English in the same way as most humans learn languages: by listening to it and interacting with the speakers. The dictionary will help them afterwards. [Answer] It would surely be very difficult. But would it be impossible? Probably not. How smart are they? Deciphering an unknown language is very hard. Giter mentioned ancient Egyptian and the Rosetta Stone. The Rosetta Stone had writing in three languages: two versions of Egyptian and Greek. Archaeologists guessed, correctly it turned out, that it was the same message written in all three different languages. As they knew Greek, they knew what the Egyptian said. Even at that, it took over 30 years from the discovery of the Rosetta Stone before significant progress had been made in learning to read the Egyptian language. If the dictionary has pictures, that could give a jump start. Like if I found a Zobling dictionary and there was a picture of a frog next to the word "drabnatz", I might guess that "drabnatz" means "frog". Then I could look for other entries that use the word drabnatz and speculate that those words might be related to frogs in some way. Life if I identified many words for different types of amphibians, and then an entry that mentioned several of these, I might guess that is the word for "amphibian". But wow, that would be hard and slow. I wonder now: Has anyone ever deciphered a dead language without having any translations of text from that language into a known language? I don't know of any but it's not my area of expertise. [Answer] A regular dictionary would be useless. It is designed to help someone able to read read anything, but gives no help learning to read. A dictionary with some pictures might be useful to a clever enough people though. The first step would be noting that the same symbol group appears both in an entry and a caption on the same page, and figuring out what entires and captions are for. After enough study it might be found that every symbol has its own page, and almost ever symbol group has an entry with at least a similar left side. But if they have a picture of something that exists and a caption relating to it they don't need to bother learning to read to show us they are intelligent, just put the caption's symbols near the real thing. Or even easier just write any of our symbols anywhere. So far no non-human has taught a non-human to write any particular symbol, so that would be a big eye-opener. If they appropriated our symbols to transcribe their language (if they don't have language the whole thing is hopeless) they could pass notes between themselves which any human would very quickly identify as intelligent. [Answer] H Beam Piper's Omnilingual may be of interest. In it, humans find the remnants of a now extinct Martian civilization. After finding Martian texts humans become extremely interested in deciphering the Martian language, but have difficulty because there are no Martian-English texts. > > They eventually find several scientific documents (including a periodic table) and realize that some things (especially physical laws) are constant throughout the universe, and use this knowledge to build a small vocabulary of Martian words from which they begin to be able to read texts etc... > > > Maybe the Zoblings find a high school science textbook and follow suit. (Another poster already said "Math is universal", but I thought a previously published book may be helpful.) <http://www.gutenberg.org/files/19445/19445-h/19445-h.htm> [Answer] We have examples of this from our own history. Faced with an unknown language we can decode the parts of speech but not the meaning of words. A dictionary will be of no help in this--it will give them more information about the relationship of words but not what any of them mean. You say they are intelligent, though--that means they have another language to use. Math is universal. Ever see those puzzles where you are presented an equation with things in place of numbers and need to figure out the numbers? Note that that's easy enough to be used a puzzle, not something you need scientists for. Your Zoblings simply need to write out a 20x20 times table and present it to someone of a scientific bent. (20 isn't an absolute, it just must be larger than their number base. The bigger the chart the easier it will be to recognize what's going on.) [Answer] A regular English-English dictionary will be useless without any other reference. However, if Zoblings are lucky to get their hands on one of the elementary dictionaries for English learner's and they have some linguists they might be able to master about 1000-2000 words needed for basic communication. Unlike regular dictionaries, dictionaries for English learners come with pictures (both for nouns and verbs), are written in the simplified language (their vocabulary and grammar are limited), have extensive explanations and tons of examples. Moreover, the most important and frequently used words are highlighted. It will not be an easy fit even assuming that Zoblings are highly intelligent. I would also assume that their knowledge of grammar will be very limited unless they find some grammar books. It is also important to consider that languages reflect environments, physiologies, and cultures. If Zoblings are unable to observe humans and their physiology is significantly different from human the cultural barrier can be too high. Real linguists start to learn languages in native settings by learning the words for body parts, objects in the environment, and basic actions. This creates a common frame of reference. However, if there is no common frame of reference comprehension can be significantly impeded. Even pictures can be of little help if Zoblings cannot put them into a right context. ]
[Question] [ Would putting a dye on my eyeball to make my sclera (the white of my eye) turn black bring any advantages? I know that wearing black around the eyes reduces glare (as in that functional makeup some athletes wear), and you can see eyes surrounded by black has evolved on animals that hunt in sunny areas, e.g. the cheetah. I wonder what would be different about a world viewed from eyes with black sclerae and a world viewed as we normally see it. [Answer] # There is no visual difference The white you see is, as Frostfyre linked in the comments, down to the [sclera](https://en.wikipedia.org/wiki/Sclera). It just a connective tissue that supports the optical parts of the eye. # Social differences A theory on why the Sclera is white, called the [cooperative eye hypothesis](https://en.wikipedia.org/wiki/Cooperative_eye_hypothesis) suggests the white of the eye is there to provide contrast such that another human looking at you can see where you're looking. This is proposed as a useful method of non-verbal communication, as a warning, an indication of where to go or even just an addition to the already diverse portfolio that makes up body language. Your black Sclera would remove this teamwork/social advantage. [Answer] **People cannot know what direction you are looking** As you say, there would be less glare, but it would also mean that it is difficult to distinguish pupils from your sclera. There is also a precedent; black spider monkeys for example often have black sclera. Or... possibly massive irises that fill the entirety of their visible eye. [Answer] Your vision wouldn't change but you would definitely stand out in a crowd as unusual (and creepy) and be very striking if you had bright blue eyes. It might have a military use as part of camouflage for soldiers (or burglars) sneaking around at night. [Answer] Combining comments from @AlexP, @AngelPray, and myself: If your sclera naturally started out as black, it would not have any impact on your vision. The sclera is opaque. Being opaque, it does not transmit light. Light enters the eye through the pupil. This has been known since at least the Renaissance. For example, see the free book Hand-book of Natural Philosphy. Optics by Dionysius Lardner, London, 1856, available on Google Books. <https://books.google.ro/books?id=9jkDAAAAQAAJ> But this question is about someone changing the color of the sclera with dye. If done right, doing so would not change vision at all —for the reasons described above. But the dye can harm your vision if applied improperly, as reported in one well publicized recent news story: <http://www.chicagotribune.com/lifestyles/health/ct-eyeball-tattoo-complications-20171002-story.html> ]
[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/101222/edit). Closed 6 years ago. [Improve this question](/posts/101222/edit) One of the signs of Alien Life visiting Earth has been mysterious crop circles. For argument's sake let us assume that aliens are real and they are leaving these behind. Crop circles generally appear at night when it's logical to assume there is less activity in the area as humans are recuperating. This would suggest that our space visitors want to do what they want to do on earth (observe us sleeping, relax under our sky, steal shit) when there are less prying eyes. Assuming this is true, then why would they leave behind evidence where they landed? Why not land somewhere that leaves less evidence like a field not covered in stall stalk of crop like corn or wheat, or even try and hide it by blasting the place so it destroys the crop circle and leaving behind a rock so it looks like a freak meteor strike? [Answer] To me, this is classic misdirection. Let's say you want to investigate humans in (say) Paris. The last thing you want is people **actively** looking for you there. But, humans are a curious lot and after that complete misunderstanding at Roswell, they've learnt that humans are going to be looking for them regardless of what they do. So; you know they're going to look, so why not give them somewhere to look that's somewhere you're not going to be? You go into (say) Ireland at night, make some pretty scary crop circles, and haul tail out of there by 3am, giggling to yourself. You then for the next week are pretty free to do your investigations in Paris (the few active UFO hunters there have hauled tail to Ireland to check out the latest evidence) undisturbed. Quite frankly, if I was a UFO hunter, the last place I'd be looking is where the lights in the sky or the crop circles are. If they're not weather balloons and drunk guys who're bored of tipping cows, they're the aliens saying 'Hey! Look over here!' while they're doing their real work in a different location. [Answer] It's a cultural thing, you wouldn't get it. Like heart-shaped carvings on a tree, fireworks on new years eve or disks through the lower-lip. [Answer] It is an experiment to test how *homo sapiens* reacts to certain input in the environment. After all, our scientists also change setup of experiments during low activity times and then observe how the subjects, be them apes, mice, bee, humans to say some, interact with the modified set up. [Answer] One thought I had is that they are marking locations for future use, eg. after careful calculations, the marked spots might be key locations to setup some processing structures - or pressure points that might be easy locations to split the earth into chunks! Much like city workers spray paint roads to mark where a hole should be dug for a future plumbing/street work. [Answer] **They're searching for something.** The circles are produced by spot searches for something they believe is buried under the ground and very well camouflaged, such as a ship belonging to an adversary, and the sophisticated sensor package required to detect it produces a variety of gravitational anomalies which as a side-effect, flatten fragile plant material. The patterns are a fingerprint of the complex fractal gravitational interference patterns used in an attempt to bamboozle the sought object's active camouflage. [Answer] There is one interesting use of crop circles in a TV series called *Ben 10 - Alien Force* where the aliens were using crop circles as a sort of circuit boards to make weather machines. You could say the crop circles are a way of changing the environment in a bigger attempt to terraform the planet, or it could be a weapon that fuses metal to organic matter at high speeds and ends up flattening the crops in weird designs. [Answer] **Transient marking visible from the air.** Like crop art (art exhibits made by mowing fields in given patterns) crop circles are markings visible from the air but not easily visible or decipherable from the ground. if aliens visit earth it likely to assume they use flying vehicles. a crop circle can be a marking providing guidance or relating information to flying object but their temporary nature provides for a sort of self destroying message. and if you consider that such formations involve marked recessions in the surface (tall stalks vs flattened stalks) it can be possible to detect them by scanning the ground topology with radar or sonar like devices (similar to mapping the ocean floor) therefor eliminating the need to visually inspect the ground which may be problematic in the night. ]
[Question] [ So I have been doing some thinking and I now am trying to design some aliens who can exhale very cold gasses or cool the atmosphere around them as a side effect of their metabolism and also survive in an environment around room temperature, so does anyone know what kind of metabolism would do this to either refrigerate air or release cold air, effectively giving a creature limited freezing powers? [Answer] What we're looking for is a cold-blooded creature that uses a [phase change material (PCM)](https://engineering.mit.edu/engage/ask-an-engineer/are-there-materials-that-can-absorb-heat-without-becoming-hot/) to line the throat and lungs that absorbs heat with the passage of air. An example of a phase change material is ice. Ice retains its temperature until it has completely melted. Pick up a partially melted piece of ice and it's the same temperature. Better still, pass warm air over it and you get cold air on the other side until the ice is completely melted. Now, here's where I'm going to employ some handwaving, because I'm not an organic chemistry major. What we're looking for is the the skin equivalent of ice. Rather than melting, the skin equivalent is passing the thermal energy into the blood stream. Remember, the creature is cold blooded, and this highly evolved process would allow it to withstand cooler temperatures than a normal cold-blooded creature could. Remember, this PCM skin would line the throat and lungs. And it would have the side effect of exhaling cooler air than it inhaled. How much cooler? That's a function of the efficiency of the system. But, please note the following: * The colder the outdoor temperature the less efficient the conversion. Our new creature may be capable of surviving sub-freezing temperatures, but its movements would be much more sluggish and its exhales only a degree or two colder than the ambient air. There's simply less energy to draw from the air as it gets cooler. * In a similar manner, in very hot temperatures the creature would likely obtain satisfactory heat through body absorption, leading to lower efficiency. Since it doesn't require to extract as much heat from ambient air via the throat and lungs (the blood being already warmed), the exhaled breath would be only be a few degrees cooler than the ambient air. * But, at its most efficient, which I arbitrarily delcare for exemplative purposes to be 70℉, then the efficiency is quite great and the exhaled air could be near or just below freezing. How much would this really affect surroundings? Not that much unless the creature was gigantic. Think about how much your own breath affects surroundings. Even with the worst breath in the world, your impact is less than a 10' radius and that's only an odor. Your heated breath in cold weather can't be felt (or, if you really exhale, could only barely be felt) by someone standing in front of you, much less someone standing behind you. Our creature would have a very similar effect. It could, perhaps, cool someone's drink or, in hand-to-hand combat cause mild frostbite, but that is likely the extent of the effect. There's simply not enough breath involved. **P.S., there is a non-organic way to do this, too** [Thermoelectric cooling](https://en.wikipedia.org/wiki/Thermoelectric_cooling) uses solid state materials to generate electricity from ambient temperature. Basically, it's a thermoelectric heat pump. This is mega cool tech, but because it's non-organic, the materials involved cannot be directly used. However, it is done in nature with ice and synthetically with thermoelectric coolers. Really, that means you only need a cool name to describe a biological PCM and you have something that meets the standards of suspending disbelief. Cheers. [Answer] In his comments, David Culp is essentially correct. Cold is the *absence* of heat, therefore your aliens could use the ability to generate extremely endothermic reactions as a weapon. The most common endothermic reaction in nature is photosynthesis. It uses sunlight to convert water and CO2 into O2 and carbohydrates. Water and CO2 are the lower energy chemical configurations, so to use O2 and carbs for energy release, both plants and animals rely on something *storing* energy in that form, and that is what photosynthesis really is; storing energy captured from sunlight in chemical form. So; your aliens have an extreme form of that process that allows them to capture massive amounts of heat energy from their environments and convert a large amount of CO2 and water (or other low energy chemicals) into more useful O2 and carbohydrates (or other high energy chemicals). The limitations to this is that you would need to store water inside you for this process, not to mention find some way of storing CO2 that can't be reabsorbed into your 'bloodstream'. It could probably only be used once every given period (you'd need to replenish the water and CO2 levels) and it also means that your aliens probably only eat for nutrition, not energy. That means in effect that they may absorb proteins and trace minerals from soil, plants or animals to maintain their health, and use this freezing capability to 'feed'. If your aliens came from a very hot planet (say, 70 degrees C) then this might be a survival response, which would also describe how it evolves. That would not make them any less dangerous to humans. On the contrary, they could use the freezing (really heat absorption) process to stun or immobilise their animal prey, then absorb their nutrients at their leisure. [Answer] There is no eay to do this, unless: * The creature has been designed by magical means; * The creature has been developed by a civilization with a technology so advanced that it is practically magical to us; * DC/Marvel style super powers. The presence of reality check and science based tags makes this creature somewhat hard to design. There is no living creature that cools the air (or water) around itself. Not even plants, which depend on photosynthesis - an endothermic process! Your creature could maybe have ammonium chloride stored in a gland, in the form of microcrystals and protected by fat. It could secrete this substance along with sweat, and the dissolution of the crystals in water would be endothermic - i.e.: it would feel cold. The problem with this approach is that it would take too much mass to make this creature able to work even as a half-broken air conditioner for a very small room. Simply not feasible. But since you also put in a sci-fi tag... If the creature has some endothermic metabolic processes, and can somehow take energy from our perceived three dimensions to use that energy in body parts that exist in four or more dimensions, then it could do what you want it to do. In Joe Haldeman's Marsbound trilogy, there is a creature that feeds on "energy" from its surroundings. The being, called Spy, describes his metabolism thus: > > “I know it takes a lot of energy, or something like energy, to put me here and keep me here. I ‘absorb’ the kinetic energy of bullets and the chemical energy of food and the radiant energy from sunlight, and it all helps keep me here.” > > > And then later on, when questioned about the effects a special kind of nuke would have on him: > > “A constant blast of radiation? I’d love it! A banquet.” He looked up at the sky. “I can feel a little secondary warmth reflected off the atmosphere, from the one you flew over yesterday.” > > > The book does not elaborate further on this, but such an "energy-eating" being could probably lower the temperature of their surroundings merely by feeding. Finally, in the indie videogame FTL, there is sentient species that quickly sucks up the oxygen of whichever room they are in, creating vacuums. In a small, sealed room this would lower air pressure, which also reduces temperature. [Answer] Would it be helpful if the freezing power weren't constant but on-demand? It could have an organ, which basically works like a freezer: stores super-dense gas and releases it quickly into an appendage, which is then cooled. Although then this freezing power would only work with touch and not in a "freeze ray" type of thing. The "freezing power" would work like a snake's poison bite: it would have a limited charge, and the alien would need time to rebuild it. Rebuilding it would possibly take a long time or a lot of energy. It would need tissues capable of holding gas at very high pressure, and it would need tissues which resistant to sudden freezing and then thawing up. [Answer] # Use [Joule-Thomson expansion](https://en.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect) A real gas expanding from a higher pressure to a lower one will cool if that gas is below its inversion temperature. The inversion temperatures for N$\_2$ and O$\_2$ are both above 600 K, so when you expand regular air from a compressed pocket, it is cooled. For Joule-Thomson expansion, the rate of change of temperature with change in pressure is equal to the Joule-Thomson coefficient. A graph of temperature against pressure, called an inversion curve, can be generated from experimental data. An example for many gasses can be found in a NASA technical note [here](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720020315.pdf). From Figure 6a, following the isenthalpic line at enthalpy 400 J/g, we can see that nitrogen gas starting at 40 MPa and 280 K expanded to atmospheric pressure (about 0.1 MPa) will drop in temperature to about 240 K, well below freezing. Lets adjust the slightly, so that starting at body temperature will allow you to blow out a gas at 260 K; or about 8 F. Lets say you want to blow an entire room full of cold air. A 4m x 4m x 3m room has a volume of 48 m$^3$ (lets just say 50). At a pressure of 40 MPa, your roomful of air will take up 0.125 m$^2$. That is still a lot of space for an alien to store internally, since that is about the volume of a human. But if you were able to store that much gas at that pressure in some internal organ, you could blow a room full of air well below freezing. A few things to note. Higher pressure will not benefit you since 40 MPa is the maximum inversion pressure for nitrogen. Above this pressure, the expansion of a gas will cause heating, not cooling. Also, if you can get the gas to be colder in the first place, this will help you a lot because for nitrogen the cooling effect is more pronounced at lower temperatures. While starting at 300K you could get 40K of cooling; if you started at 250K you would see more like 60K of cooling. That is to say, if you use an endothermic process from one of the other answers to drop the temperature of your compressed air organ to 250 K before expelling it, you could then blow out a roomful of air at about 190 K; colder than the coldest temperatures on Earth, cold enough to freeze carbon dioxide. This would be easily cold enough to cause frostbite on exposed fingers and ears in a minute or less. [Answer] Let's review a few methods. We have a lot to work with when it comes to super cold things you can spray at people. You mentioned a gas. Cold air can be harmful, but when it comes to materials they're generally not affected too drastically. At the other end of the spectrum, solids are hard to spray at people and are somewhat unfeasible for a living creature. Liquids are our optimal "projectile", if you will. ## METHOD ONE: Decompression (not very feasible but gets really cold) To get familiar with refrigeration, let's look at.. well.. a refrigerator! How does it work? In layman's terms, it compresses a gas, then decompresses it. This decompression causes the gas to rapidly drop in temperature. The reason this happens is that the gas rapidly expands; this expansion is fast enough that the energy in the gas remains the same, but the volume increases, meaning that the energy per fixed unit of volume goes down overall. See [this StackExchange physics answer](https://physics.stackexchange.com/questions/14140/why-does-the-gas-get-cold-when-i-spray-it) on the exact mechanics behind this cooling. With this knowledge we could start building a creature. It would need pipe-like structure for carrying gas/liquid, that is resistant of cold and can hold reasonably high pressure. It could store pre-liquefied gas in a sort of biological "dewar"; unfortunately, I'm not too sure how this may work), and when the time comes, it can spew cryogenic liquid through an orifice lined with material to shield the rest of the organism from the cryogenic material emerging from itself. Issues with this method are that it's generally quite hard for an organism to store materials that cold or materials at such high pressure. We could try using a high melting point gas, but a Freon-shooting dragon doesn't have the same touch to it. ## METHOD TWO: Endothermic reactions (more feasible, not as cold as fast) In order to understand how this method works we will have to dive deeper into coldness. If something is cold then its energy is low. Endothermic reactions are reactions absorbing energy from the outside. Thus, we can take a material and use an endothermic reaction to absorb the heat energy in it, making that material "cooler". This is how ice packs work. The creature could secrete chemicals it stores in separate chambers, which it then combines during a time of need to create a cold slush. It then expels this mixture towards its target. This is somewhat reminiscent of a reverse bombardier beetle (which sprays a hot mixture instead of a cold one). Issues with this method are that it doesn't get nearly as cold as the previous method. [Answer] Perhaps an organ in the head, like a snake has a venom sack, that processes nitrogen or some other naturally occurring element into supercooled liquid. It could then spit the liquid onto the objects it wanted to freeze. ]
[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/87895/edit). Closed 6 years ago. [Improve this question](/posts/87895/edit) In my setting, a war between "rationals" and "irrationals" has led to the establishment of a global society that makes all it's decisions based on logic and science. What is a believable threat to the way of life of a civilization such as this? [Answer] > > Your scientists were so preoccupied with whether they could that they didn’t stop to think if they should. > -Ian Malcolm, Jurassic Park (film) > > > So the threat to this civilization is "Can we vs Should we" and there are all sorts of arguments that are logical to do, but shouldn't be implemented. In the world of Jurassic Park, the first half of the film is devoted to the system put into place to ensure we can control this. But at the start of the initial tour (the only ride that will be available when the park opens to the public) we start to see the wheels come off. The dinosaurs aren't attention whores, there are enough problems to occupy a full time staff at both a theme park and a zoo and they are in the process of downsizing, and safety features were deliberately ignored (the game warden has a wonderful "I told you so" moment when the entire party leave the ride vehicle while the ride is in motion... what theme park ride doesn't tell you to "keep your hands and feet inside the ride at all times" let alone have some kind of barrier to make sure the rider isn't injured should the choose to take that rule under advisement? Well, the rides that have 30 foot tall live animals that eat meat and can swallow humans whole!). And the final nail in the coffin is that the guy charged with implementing all this modern automation has vocally complained about how he's not being paid enough for his trouble and everyone believes he's working towards the best interests of the guy stiffing him. Yes, these people can bring dinosaurs back to life, but these people should be the last people you want to bring them back. But that's a big fantastical problem... a more likely society problem: How does this society deal with elderly? Well, operating in pure science and logic, elderly people are drain on the community. They need care, which takes away individuals from care of more healthy and viable populations, they don't contribute all that much to innovation... often stubborn and resistant to any changes of a modern society (the earliest known utterance of "Kids today have no respect" traces back to a tablet found in Mesopotamia, which feared that contemporary youth would doom civilization as we know. Kids Today: Number One threat to Civilization since 4,000 B.C.). Science says they will not likely to amount to much more in their life. Logic says that if resources must go to either an elderly person or a young person, they should go to the youth because they have more potential contribution. And medical spending on senior citizens is always higher than on youth on a one to one basis... and if taken to the full logical conclusion, we must assume that upon retirement, granny moocher should be terminated for the good of society, whether she or her family want to or not. Now, scientifically and logically speaking, can we kill Granny without her consent? You bet your euthanasia we can. But should we do that? Well, in our modern culture, this is a horrifying idea. We still have trouble with letting terminal patients the right to doctor assisted suicide to allow them mercy for pain, let alone getting anywhere close to "Throw them a nice retirement party before we cast them as the title hero in our remake of 'Old Yeller'." Even Star Trek's Vulcans, which worked as a society of logic and science still was plagued by emotions and those would factor into their decision making. Spock, the advocate of logic, even said that there are situations that, when logic cannot be relied upon, it was acceptable to act in illogical ways which is a nice way of saying "Be as logical and scientific as you want... just don't be stupid about it." And since this situation is a human society, a logical course must take into account an illogical emotional creature. As pointed out in Men In Black, "A Human is smart. Humans are stupid." Now, you can try to build a system that can contain human stupidity... but I'd sooner trust the fine folks at InGen to build a dinosaur zoo than I ever would a person who believes she can build an idiot proof system... Human stupidity is a part of life... and as we all know, life finds a way. [Answer] The unpredictable human is the threat to the perfectly ordered rational society. In Star Trek TOS Kirk often beat Spock at chess by making unpredictable moves and going for long shots. This is how humans work! We aim to misbehave! In recent events, when Trump first declared his candidacy few took him seriously enough to mount an effective opposition. And when attempted to persuade people from their opinions using logic and facts it failed completely. You can't reason someone out of an opinion they did not arrive at using reason and logic, you have to use emotional persuasion. This becomes even more important when science and rationality have been weakened by selling out to the highest bidder (no smoking isn't bad for you we have scientific studies). Lies, damn lies, and statistics; facts lose credibility when anyone can use the same data to show what they want. I think it is pushing believability that such a utopian society could ever actually form. But if it did, it would quickly fall when all of the human people failed to act rationally and logically in unpredictable ways. Most human decisions (including political ones) are not made rationally they are made emotionally and we use logic to justify and rationalize the decision we have already made. Social scientist (I'm looking at you economists) often lament that people aren't acting rationally according to their current theories, rather than studying how people actually act and changing their theories accordingly. A rational society that you propose would most likely simply be a despotism of the scientific elites, which can choose to ignore the input of those deemed irrational. This would quickly lead to an underground movement of the oppressed who would make all sorts or un-rational decisions like choosing to fight and die against perceived injustices. [Answer] To those above: Rational/Logical government does not mean what people think it does. The kind of totalitarian, bulldozer, Borg-like version of 'Logic' is not, by definition logical. Because a rational system would aim to maximize things like total economic productivity, and average human wellbeing (including psychological well-being), whilst also putting in place ways of improving these things. This is hard, but not impossible in theory. There would be a lot of empiricism involved - perhaps 'Try Policy A in one area, Policy B in another, see what works'. Testing by experiment is very much a 'rational/scientific' thing, as is changing your mind when these experiments give data that doesn't agree with your pet theory. The best example I can think of in fiction would be [The Culture](https://en.wikipedia.org/wiki/The_Culture) So.. our rational society can deal with physical challenges - indeed, by acting rationally it can avert self-destructive things like environmental destruction. The threat could be something like a fanatical religion ; or a break away part of this society that is dedicated to war; any group that will irrationally place their group above themselves (to a much greater extent than is normal for humans). This would give them a short term advantage over a more rational society. [Answer] How does logic apply to government? Logic applies when you have a stated aim and you need the simplest path to achieve it. The straight line from A to B is logical. It's illogical to have emotional attachment to the things that are destroyed along that path. For example, it's economically logical to introduce euthanasia for people over the age of 85 or earlier if they become a burden on society rather than a benefit. Is that really a logical path you want to follow? One could say it's not emotionally logical, it's certainly not logical if one wants to remain in power. Is remaining in power one of your specifically required outcomes? If so that will lead down a path of repression of freedoms, if not then some outrageous character appealing to the basest emotions of the public could take power and undo all your hard work. *Technocracies don't tend to last long, people are too emotional.* What you're asking for is basically a technocracy, hopefully with a hint of meritocracy. Logically run by the best and brightest. Government however is about compromise, it's about negotiation, it's about allowing for arbitrary special interest groups, supporting uneconomic sections of society because they improve society, not the economy. Logic and science don't know this, only emotion does. [Answer] A few ideas that jumped into my head would be: 1. Actual magic, if some members of the society started displaying irrefutable and provable demonstrations of "scientifically impossible" phenomena that they themselves brought into existence then this could cause a threat to the way of life. 2. A system of leadership designed to make the most logical decisions for their society and in so doing they debate the logic of each decision to the point that nothing gets done and starvation and disease are running rampant. this would all be a result of their inability to make a decision that could potentially be illogical. 3. Stagnation in their science, the road to scientific discovery in our society is paved with people doing things that are not logical. These people end up discovering something previously thought impossible or illogical, and those discoveries lead to innovation. no illogical "doers" no innovation. [Answer] The biggest threat to such a culture is existential dread. There's no way to actually define "scientific" and "logical" using only scientific and logical terminology. The logical limits were explored by [Tarski](https://en.wikipedia.org/wiki/Tarski%27s_undefinability_theorem) in the earth 20th century. Science's limits have been explored many times. Thus there will always be at least one point in their society which is not perfectly nailed down with logic and science. [Answer] What you are proposing is [Technocracy](https://en.wikipedia.org/wiki/Technocracy) (or Scientocracy). The main problem is that it is not a natural form of government. People need to delegate their power to trusted scientists and experts. And this delegation, like any other delegation, has its flaws. 1. Representatives may have inadequate expertise; 2. People may disagree with the representatives; 3. Representatives may get into a stalemate between themselves; 4. Representatives may try to usurp power. Take look also at [how to design a realistically looking technocracy](https://worldbuilding.stackexchange.com/questions/53224/how-to-design-a-realistically-looking-technocracy) ]
[Question] [ Tech level: more or less contemporary, no tech that would put you in awe. I'm trying to make realistic, driverless, mass-transit system. The first idea was that "driverless" implies that in each tram there is a bit more space because driver lost his job. Simple, problem solved. Later, I started to think about this in more detail. The main reason why some trains are not so frequent but long is saving labour cost. So if there is no driver, they should be shorter. Thus passenger could be delighted that they waste less time waiting, while technically speaking the number of cars would be the same. And even metro stations could be shorter, as no one would try to stop their long train. Then I started thinking about friction. Technically speaking many short train make more air friction than few long ones. So maybe the trams wouldn't be specially shorter? Or maybe realistic trams (even with dedicated lane) would stop so often that unable to achieve any speed where the friction really matters? OK, the question is: does anyone have any detailed calculation showing how much such technical issues like length of tram and its speed matter for energy efficiency? (Or any idea idea how to make such adjustments for driverless trams not based on gut feeling but some more or less hard data?) (No, no individual pods, too expensive and fancy for my setting.) [Answer] # This already exists As an urban transportation nerd (side note, go follow [Urban Planning Stack Exchange!](http://area51.stackexchange.com/proposals/100985/urban-planning)) this is a big deal, and is the future of transit. The thing is, automated trains already exist and already work. The Vancouver [SkyTrain](https://en.wikipedia.org/wiki/SkyTrain_(Vancouver)) has 79.5 km of track and 53 stations. It has been in operation since 1985 and is fully automatic. For comparison, the Chicago 'L' system has 165 km of track and 145 stations; so Vancouver's system isn't tiny on the scale of things. Automated trains are possible, work well, and are the future of mass transit. Go tell your local council-member, MP, or senator today. --- There are many other systems out there, in addition to Vancouver's; [via Wikipedia](https://en.wikipedia.org/wiki/List_of_automated_urban_metro_subway_systems). That article talks about levels of operation: some subways are more automatic than others. --- To answer the question more exactly, there are no differences in operating characteristics from human driven to automated trains. For example, the Red line in Washington DC last year shifted from human driven to Type II automation: computer driven with a human operator on board. There was no change in schedule, train length or train frequency. There is no reason to want to shorten the trains. Trains do not have a relative advantage over cars until population and job density gets very high. There are only a few cities in the US for which an urban rail network makes sense: New York, Chicago, Boston, San Francsico, New York, Philadelphia, and Los Angeles. In other cities, the transit system would make sense only if efforts were made to increase either the population density in the downtown areas (Houston, Atlanta) or the jobs density (Dallas, Miami). Some cities have good downtown density, but just a bit too small (Minneapolis, Seattle, Denver). Since urban rail is only an advantage to move large numbers of people in places where there is not enough room for cars, rail should concentrate on building to at least half capacity. The highest frequency subways in the world can get up to almost a train a minute through the busiest stations along the same line. NYC's 4/5/6 on the East Side runs about 49 trains, 8 cars long, per hour along the length of Manhattan during AM peak hours. Headways (time between trains at a station) are the limiting factor here. If a rail system can't fill the tracks, then it can't make the money to pay for those tracks. Rail has high upfront capital costs and relatively high capital maintenance costs. If you drop cars from your trains, you are still limited on headways, even on automated systems. That means you are just dropping capacity and revenue. The advantage of automated trains is in the labor costs. As I pointed out in the comments, for the MBTA in Boston, The [FY15 Budget](http://www.mbta.com/uploadedfiles/About_the_T/Panel/MBTACapitalandOperatingBudgets.pdf) (slide 3) for was \$1.9 Billion, of which \$740 million, or about 39% was Labor costs. Based on the Boston Globe's [breakdown of MBTA employees](https://www.bostonglobe.com/metro/2016/01/27/nearly-mbta-employees-made-more-than/UAZ1tQmWzK5fjFjTYPMj0N/story.html), around 40% of overall employees (bus and train) were drivers. Eliminating drivers could reasonably be expected to cut 20-30% off of operating costs for the trains. This would allow the shifting of more money to maintenance and expansion, and reduce the government's need to invest in the system, which would, of course, increase its political appeal. Automated heavy rail the future of dense urban transit for cost based reasons. That challenge is to convince society, especially in America, to live in increasingly dense conditions to take advantage of this heavy rail future. If we can, there will be significant economic, equality and environmental advantages. [Answer] As with anything, there are pros and cons. There is not a significant difference in friction between the cars and the rails - each car weighs the same regardless of whether cars are adjacent to it and each car is supported on its own wheels. Shorter trains will experience more air resistance, because the cars at the beginning and end of the train (where they either plow through the air, or suck it along behind them) contribute the most to air drag. However, the real issue is *traffic*. Rail cars are definitely not immune to traffic. In my city (Denver) it is quite typical, especially during peak times, for light rail trains to either have congestion among themselves at junctions, or interact with automobile traffic. For safety reasons, no more than one train at a time can be in any particular station or section of track, and so replacing four one-car "trains" with one four-car train will effectively quadruple the capacity of the railway. Similarly, a four-car train doesn't take much longer to pass through an intersection shared with automobiles than a one-car train does, since most of the time is spent waiting for traffic signals rather than actually rolling through the intersection. Overall, bundling the train cars together makes the interaction with automobile traffic or other rail cars much more efficient. While future technologies might narrow the safety margin somewhat, one limiting factor will always be space on the platform. Since light rail systems are built in dense urban environments, it's not often practical to build parallel loading platforms, and only one train at a time will ever be able to use the platform. Longer trains will always have this advantage over shorter ones. What you might eventually see are longer trains during peak times, and shorter ones during off-peak times. This already happens of course, but it might happen to a greater degree, allowing greater frequency of service during off-peak times (compared to how it is now). [Answer] [Transportation Research Board](http://www.trb.org) is a good place to start looking for hard numbers. Driverless vehicles can indeed run more frequently. That frequency is goverened by the limits of the busiest segment of the line. It doesn't matter if the infrastructure at Outlying Station A can support a train every 90 seconds. What matters is Downtown Transfer Station B, serving trains from all three branches, where the dwell time might be 60 seconds, and most cars are 80% full. *That* location determines the capacity of the entire line. Labor costs are important, but are roughly comparable to energy costs. Other costs include maintenance, capital costs of vehicle replacement, insurance/liability/safety compliance, security, fare-handling, and administration. There are cost tradeoffs - more frequent automated vehicles will travel more miles each year, requiring more maintenance and more frequent replacement. Guideways will wear faster, requiring more frequent shutdowns for repair and replacement. Additional infrastructure costs like more frequent inspections, sensors, and a small cadre of programmers may be needed, reducing (perhaps eliminating!) the labor cost savings. It's likely that more frequent vehicles will attract more riders, which increases revenue...but more riders also means more security, more station and car cleaners, and associated incremental costs, too. Increased ridership also makes that critical maintenance more challenging, shrinking work windows to middle of the night, and raising their cost. You can shut down an entire line for a day or a week...but there will be a different type of price to pay. The question dealt a lot with energy questions, so here are some energy answers: In general, most vehicles (like trams) have negligible air resistance below about 30 mph...but air resistance is a power curve, and climbs quickly above that. City trams can be boxy because they are slow. Slow vehicles lose much more energy to motor efficiency losses and transmission losses than to air resistance. Above 30mph, subway and commuter trains are longer, and do benefit from some energy savings, though that's usually incidental. These large-infrastructure systems often have expensive legacy constraints like platform length, siding locations/lengths, network branches, shared traffic, and signalling systems that make many changes unfeasible without years of planning and investment. Both maintenance costs and energy costs are also affected by the *weight* of the vehicles. Lighter vehicles pound the guideway less, and require less energy to move...but lighter materials are often less durable (fiberglass) or too expensive (carbonfiber). Materials must be resistant to the inevitable casual vandalism by riders...which is why stainless steel and plexiglass, though heavy, remain common. [Answer] What I envision is an automated car that will come or stop for you on demand; larger cargo pods are also available. You get in and tell it where you want to go. These start out and finish up as singles, but link up into trains to aggregate traffic sharing a route. They would also automatically load into encapsulators to make use of different modes of travel; e.g. pods are normally efficient local electric cars, but link into a train pulled by a powerful engine when taking a freeway a longer disance, or load onto what are essentially rail flats to take a light rail system; likewise for boats or air travel. On a rail-only system like you are asking, will it be a fixed route loop, or allow choosing a destination? Let me make an analogy with elevators: new systems more than double capacity and reduce waiting for each passenger by having you state a destination in advance and then taking the indicated cab. A fixed loop rail, ideally with pulloffs for stations, could have the same benefit. You get in a car that goes where you plan to get off. Groups going the same way for any distance will link up on the fly, and unlink when one wants to go a different way at a junction. If tracks are shared among different possible routes, you need a minimum space between trains for safe switching. But in general, a group travelling on the same segment that are close together will link up on the fly. [Answer] Subway car frequency and speed - which it seems you are attempting to optimize for - is quite definitely not limited by cost of the labour of the 'drivers'. It is limited mostly by the fact that you want to run a schedule and you need to have some wiggle room when someone blocks the door or something, because you don't want the next subway car to have to break like crazy every time that happens. The result of this is that practically the highest frequency turns out to be about one subway car every two minutes (whether you look at driverless rail systems like the SkyTrain or countless of normal subways all over the world) and making them shorter is not going to make that any better (if anything the added complexity would just make it worse). ## Bonus: Morgantown Personal Rapid Transit system If you just want a creative alternative driver-less system (with definite advantages and disadvantages) than this multi-lane solution is worth a look at. Every station has its own 'off ramp' and every 'car' goes straight from start to destination without stopping at stations in between. Turns out that in real life it's not really worth it, but it's quite an easy sell in when world building. [![Two cars passing as they move in opposite directions](https://i.stack.imgur.com/PsZHO.png)](https://i.stack.imgur.com/PsZHO.png) > > The Morgantown system uses automated control and operates in three modes, "demand", "schedule", and "circulation".[15] > > > Demand mode operates during off-peak hours and reacts dynamically to rider requests. After pressing the button to call a car, a timer starts. If the timer reaches a predetermined limit, typically 5 minutes, a vehicle is activated to service the request even if no other passengers have requested the same destination. Also, if the number of passengers waiting to travel to the same destination exceeds a predetermined limit, usually 15, a vehicle is immediately activated.[15] In this mode the system operates as a true PRT. > > > During peak hours, the system switches to schedule mode, which operates the cars on fixed routes of known demand. This lowers the waiting time for a car traveling to a given destination and is more efficient than demand mode. During low-demand periods, the system switches to circulation mode, operating a small number of vehicles that stop at every station, like a bus service. This reduces the number of vehicles traveling on the network.[15] > > > Source: <https://en.wikipedia.org/wiki/Morgantown_Personal_Rapid_Transit> And here is a nice video showing it <https://www.youtube.com/watch?v=iaSaWfw07Sw> ]
[Question] [ The generational ship is a small closed system, nothing comes in, nothing goes out. The population is under 10 thousand and stable, it's in the middle of its run. No surprises, just day to day routine running. **Would it be possible to maintain a "free" democratic capitalist civilian government or would it ultimately have to run on military lines?** Here we're assuming that a democratic government allows people to try to make a profit in their dealings with each other. It permits the usual greed of the individual. All are equal in the eyes of the law, it's the best system that money can buy. Under a military system people do what they're told, promotion by ability, waste is controlled, catering is probably central. Leaders retire at an appropriate age. Everyone has rank and knows where they stand relative to any given other person they may encounter. *Answers can show communist, social democrat, mad dictator or other government types are also valid but any answer must try to show that the system of government would be stable or that no system would be stable.* [Answer] You would get both, or you would get unrest. You have to have military-like structure, with captain on top. That's just something any ship needs to survive. When something brown hits the airshaft, you don't have time for democratic decisions, for talk, for uncertainty. And here comes the military-like chain of command. Without it first problem and congratulations, you are dead. On the other hand, people don't like so much discipline. For sure large part of them don't. Majority, maybe. They need to feel they are not slaves. Oh, and you need someone to care about food supplies, education, health care. You don't need a chain of command for this, you can allow people to elect some kind of council all right. All decisions that can't endanger the ship. This way, you are giving your officers more time, and your commoners some way to feel important. And ambitious untrained people still can get a nice title where their incompetence won't kill anyone. [Answer] **You would need both, separated in key areas.** The problem lies in the conflicting areas of motivation. In a military society, there is duty to one's superiors. You obey them, simple as that. As long as the man at the top has good control of his men and intends to do the 'right' thing, the military system won't collapse. But since the apparent goal on this ship is a democratic society, there would need to be checks and balances which are complicated by the non-renewable nature of resources. **Quite simply, in a capitalistic society, people have the tendency to treat one another badly**. Financial transactions, at the level of the individual and small enterprise (which is probably all that could exist on a generational ship) are zero-sum games. Whatever one party gets, the other party doesn't. So, it is better for either part to get whatever advantage they can over the other. In today's economic system, this is balanced by the fact that there are other vendors of almost any product. If you want to buy but don't like the price, go somewhere else. If you want to sell, but no one is buying, lower the price to make yourself competitive. This fails on a generational ship due to lack of resources and lack of population. There isn't an unlimited supply of medicine; if you don't like the price of the ship pharmacy's heart medication, it is pay or die. It gets even worse when we consider if the ship's systems are privatized. Imagine someone with control over the air flow to different parts of the ship. That's the biggest advantage in a financial transaction you can get: pay or die slowly. **This is where the military come in.** If the military, assuming that they are committed to the mission succeeding, can safely control the life support and other ship systems, there goes the biggest fault with the democratic capitalist system. The next part is where it gets tricky. The military would need to enforce some kind of welfare system. The most important resource on a generational ship is the population; they're the entire reason it's there. If the military operated as a not-for-profit, and collected taxes in the form of necessary items, these could then be distributed to the poorer factions of the ship, preventing any unneeded deaths that could damage the integrity of the genetic diversity of the sip, and therefore the mission. **To sum up,** a capitalist system could work but the military would need to be in control of the ship itself and have required access to other supplies. Luxury items, food (that was better than the most basic fare) and everything else could be controlled by the capitalist system but it is important to remember why they are there. The mission on the generational ship should inform everything. The mission is why they are there and everything on the ship should be directed to making sure it succeeds. [Answer] ## You don't have the resources for full capitalism Just a few point that immediately sprang to mind: * The people are a resource you want to keep (this is always the case but with small populations it is more so). So you cannot really risk endangering their lives too much. * You are limited in the amount of material you have. You need to keep enough in the hands of the engineers to make repairs and so can't afford full capitalism in terms of machines. * What you can charge for could be virtual, there would be no physical cost to producing games/videos/VR assistants etc but they are still desired - this is where your capitalism could thrive. * Power is limited, this could be some form of trade. A power coupon lets you run your computer for an hour, a transport for half an hour, lights for a day etc . These aren't essential, however, and you could earn them by doing certain tasks, trades, etc. My conclusion is that you would want a military enforced communism on the ship where their aim is solely the maintenance of both ship and people and they ensure resources are sufficiently rationed over the whole journey to keep both the people and the ship in a good condition to fulfill the aim of the mission. Your capitalism would exist in the virtual world and non-essential items. The communist side would **require each person to perform a duty** - perhaps on a rota - that keeps the ship going. **So some people are trained in running farms, some in engineering** (a big area, so this would probably get split into engines, air supply, water, sewage etc), more still would go into other roles (I just can't think what they are at the moment). You only need to do a certain number of hours a year though and - if you have a side business selling VRs or games - **you can pay someone in power coupons to do your hours for you**. This way people can do extra farming (ontop of the required amount) and have coupons to buy their games, keep their lights on longer than basic etc. Thus you have a cycle for capitalism to exist. [Answer] You want civilians in charge at the top. For why, I turn to Admiral Adama, from *Battlestar Galactica*: > > There's a reason you separate military and the police. One fights the enemies of the state, the other serves and protects the people. When the military becomes both, then the enemies of the state tend to become the people. > > > The military is always looking outwards, protecting the core against opposition. Resolving internal conflicts is a different skillset. Military do indeed train how to resolve such internal conflicts, but it's not their forte. To lead a generation ship, you want a caste who specialize in resolving such internal conflicts. I will point out the Admiral always deferred to the President. [Answer] **It might start out civil, but would become increasingly controlling/hereditary over generations.** 1. He/She who controls the life support functions (breathable air, potable water, food, temperature) aboard an isolated ship has *absolute* control. See also: <https://en.wikipedia.org/wiki/Hydraulic_empire> 2. People have a *strong* desire to protect their own survival and advantage their children. I could easily see training to operate life-support systems becoming hereditary/religious. Suggested reading: <https://en.wikipedia.org/wiki/The_Ballad_of_Beta-2> (IMHO an under-appreciated novel!) ]
[Question] [ October 28, 1962. The Cuban Missile Crisis has just concluded. John F. Kennedy gathers his top experts across fields to discuss the escalating threat of total nuclear annihilation. After two weeks of closed door meetings, the president along with his advisers have come to the same conclusion with absolute certainty. They bring in additional voices--scientists, governors, congressmen, and businessmen--across the United States and further discuss the matter. The conclusion remains unchallenged, and every new voice added to the discussion comes to the same conclusion: Total nuclear war with the USSR within the next 5-20 years is entirely unavoidable if the United States attempts to maintain its sovereignty as a country. The government realizes that most is lost, however they can't accept that *everything* is lost. They need a plan; they need to do *something.* In the face of undeniable mutual destruction (to the level that could be accomplished with the weapons of that era), what could the government hope to protect? How would they accomplish this? How long might it take? [Answer] Having the ability to get as many people as possible underground is going to be important, but massive earthworks are pretty expensive, so getting ready made holes as starting points would probably help speed things up. There are a lot of caves that could be used as starting places and then enlarged: [![enter image description here](https://i.stack.imgur.com/oNinN.gif)](https://i.stack.imgur.com/oNinN.gif) A lot of the places that don't have caves do have mines that could be used. The [Salt mine under Detroit](https://www.sott.net/article/292524-The-giant-salt-mine-1200-feet-beneath-Detroit-Michigan), lots of coal mines [![enter image description here](https://i.stack.imgur.com/LINzX.jpg)](https://i.stack.imgur.com/LINzX.jpg) and other mines and excavations. This will allow you to save most of the money for shelters under the big cities. For resources you start by taking a percentage of grain and other storable foods and putting them into underground silos, dig greenhouses, and set up areas to raise animals. Medicine, and the means to make more, should also be put into the shelters, along with as much printed knowledge as you have to help with rebuilding afterward. Tools and equipment to start reconstruction and farming. You really only need to last about two weeks. Fallout radiation loses its intensity fairly rapidly. Radioactive fallout poses the greatest threat to people during the first two weeks, by which time it has declined to about 1 percent of its initial radiation level. A lot of people will die afterward from disease and starvation, but this can be minimized with a little forethought and planning. [Answer] The government basically did prepare for this. There were (are?) numerous bunkers with long term occupation in mind built across the country. Rapid evacuation plans for high level government officials. Distributed military and transportation networks so they would be very hard to totally disrupt. Clear chain of command line through hundreds of people. Ultimately, attempt to construct an anti- ballistic missile shield across an entire continent. Marine based rapid first strike capability (ballistic missile subs parked off the Russian coast). We escalated MAD to the point where even the Russians backed down. If you are asking what MORE the US could have done in order to preserve the USAs cultural legacy post nuclear war, I think rushing lunar and Lagrange point colonization with permanent occupation would be the answer. Perhaps a deep sea colony as well but I think the space facilities would be the most unreachable. If you read some of the space colonization literature from the 60's and 70's, they make it seem like we could have had orbital habitats within just a few years if we were willing to spend the money and lives to do it. [Answer] **Least Work Required** - Go with the needs of the many, not the few. ## Disband a Country or Two You said "Total nuclear war with the USSR within the next 5-20 years is entirely unavoidable **if the United States attempts to maintain its sovereignty as a country.**" While migrating millions of people underground, or building hundreds of bunkers, which require extremely large stockpiles to last the entire country's population through the fallout, may seem like a good idea, it would require unprecedented planning, precision, and money in a short time. This is not the traditional approach, and I am ready for the onslaught of downvotes, but consider what would happen if a peace treaty were written, saying something like the following: > > *The United States recognizes that both ourselves and the USSR cannot maintain* *sovereignty at once while preserving the lives of our citizens.* > > > *Therefore, we seek to resolve this dispute by ending the sovereignty* > *of our nation and demoting those in power while maintaining our* > *judicial and constabulary systems to prevent anarchy.* > > > *We will arrange a government that can cooperate with other countries effectively, or divide into smaller democratic countries, and we strongly implore you to do the same. This will maintain the peace.* > > > *In the event that, once the New United States (NUS) forms, your country has not done the same, you may expect the current circumstances to resume.* > > > *In the event that the USSR disregards this message and initiates full nuclear war, expect the annihilation of your own population by allies to the United States.* > > > *We look forward to your decision.* > > > [Answer] First, one would have to define the "survival" goal. What is supposed to survive? Most of the population? A viable industrial base? A sovereign nation? A distinctive culture? ### Consider a Preemptive Strike If the decisionmakers are *certain* that the Soviets will deliberately (or accidentally) start a war, most of the arguments against a preemptive strike will be gone. Sure, there will be megadeaths. Sure, there will be [nuclear winter](https://en.wikipedia.org/wiki/Nuclear_winter). But the best way to ride it out is to have *your* forces start a deliberate, well-rehearsed attack "out of the blue" to catch at least some of the enemy force before it can be launched. ### Shelters Identify what you need to rebuild an industrial base and put it into distributed shelters. Machine tools. Generators. Refineries. Drill rigs. *(Of course the plans will fall short. For want of a nail it will fail.)* Build shelters for the population and equip them to dig themselves out of the rubble and to travel through contaminated zones to a place of safety. The US is large enough, especially in cooperation with Canada and Mexico, that there will be some "less contaminated" areas where people can try to survive. Sure, cancer rates will rise a lot. ### Exile If the survivors had the ships to travel to Australia, would the Australians welcome them? And would the result be "USA Reborn" or "Unemployed Refugees Down Under"? The outcome will be better if it was prepared by secret negotiations and if the refugees can bring the contents of Fort Knox, plus machine tools etc. Of course if the plan got known, Australia might get plastered, too. So talk with South Africa. Argentina. If nothing else, rumors of these talks would force the Soviets to spend nukes on empty desert. Reduces the rad count in Kansas. --- ### Follow-Up: Balance of Forces In the early 60s, the USSR had only a [few intercontinental missiles](https://en.wikipedia.org/wiki/Cuban_Missile_Crisis#Balance_of_power). Their other missiles and bombers didn't have a truly global reach. Understanding the truth about the "missile gap" might make all three options more palatable. The President and his advisors might even see a limited window of opportunity to do so, and decide to act *now* to save at least some of America. They might argue "fight now, and when the dust settles 100 million Americans will be left. Fight in five years, and it might be none." Mao is said to have dismissed megadeaths that way. Don't count the deaths, count who will have more people left. Might have been bluster, might have been cold-blooded calculation. [Answer] If USSR is threatening the sovereignty of the US and a nuclear war is inevitable, clearly, Soviet Union is accepting the fact that it would be hit hard by US nuclear strike. This time, you should remember, was the exact time we started to talk about properly implemented MAD (Mutual assured destruction). If the government and experts deduce that the nuclear war is inevitable the only reasonable option is a *massive preemptive strike*. This would allow the US to destroy as many Soviet nuclear devices as possible. In 1962 majority of the nuclear attack from both sides would be carried out by bomber operations. The US is speculated to have had a slight edge in air attack and defence back in 1962, so the Presidend's and army's conclusion would probably be to strike immediately. Striking immediately is profitable as it is better to dictate the place and time of the fight, and destroy Soviet bombers on their fields. War is anyway inevitable. Another reason not to wait is that in 1962 the US, and they have to assume the Soviets too, are developing their submarine based ballistic missiles. The problem of this part of the nuclear triad that you cannot destroy it. Striking now with bombers and ICBMs could possibly destroy all Soviet nuclear devices before the are delivered to the American soil, but in 20 years a reasonable proportion of Soviet warheads will be safely underwater surviving the initial attack only to retaliate. ]
[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/56679/edit). Closed 7 years ago. [Improve this question](/posts/56679/edit) In the modern world, World War III is a near impossibility, and the Cold War has shown us that Mutually Assured Destruction prevents a large war between super powers from occurring. Sure there have been small conflicts over recent years, but no World War III. Is it possible for World War III to occur and **not** have it devolve into nuclear war? If so, how do I prevent nuclear war in World War III? [Answer] The crux of the question is preventing nuclear attack/nuclear exchange rather than preventing WW III. By some counts we passed WWIII a long time ago: Seven Years War: First global war with theatres of operation in both hemispheres (WWI) Napoleonic Wars (WWII) Great War of 1914-1918 (WWIII) War of 1939-45 (WWIV) Cold War (WWV) Global War against Terrorism (GWOT) WWVI This would make a subsequent global conflict with different actors WWVII Nuclear weapons have not been used since 1945 since the threat of Mutually Assured Destruction have kept the Great Powers from using nuclear attack, but instead, warfare has evolved to allow for conflicts to remain below the threshold of nuclear weapons release. Indeed, the imbalance of power with non nuclear weapons between First and Third world societies has become so great that warfare has moved to what some theorists call 4GW. The general definition that I like to use is: > > Fourth-generation warfare (4GW) uses all available networks — political, economic, social, and military — to convince the enemy’s political decision makers that their strategic goals are either unachievable or too costly for the perceived benefit. It is an evolved form of insurgency. Still rooted in the fundamental precept that superior political will, when properly employed, can defeat greater economic and military power, 4GW makes use of society’s networks to carry on its fight. Unlike previous generations of warfare, it does not attempt to win by defeating the enemy’s military forces. Instead, via the networks, it directly attacks the minds of enemy decision makers to destroy the enemy’s political will. Fourth-generation wars are lengthy — measured in decades rather than months or years. > > > (*The Sling and the Stone': Next-Generation War* by Col. Thomas Xavier Hammes (USMC Ret.)) By this measure, using nuclear weapons is counterproductive for the most part. Nuclear terror attacks made by smuggling in nuclear devices may serve to convince decision makers that the conflict is no longer winnable, but human psychology and historical examples like the Blitz demonstrate attacks like this could serve to harden the resolve of the nation instead. If nuclear weapons are to be used in a conflict, it would be for very specialized purposes where the release of a nuclear weapon does not raise the threshold of weapons release on the ground. Some people suspect that tactical nuclear weapons used at sea might pass this test. Nuking an aircraft carrier in the Pacific does not imply or demand a city or land base target be struck by a nuclear weapon in response. Space is another place nuclear weapons might be used freely. The high energy density of nuclear weapons allows you to carry out conflicts in space even with the enormous distances and speeds involved. [Atomic Rockets](http://www.projectrho.com/public_html/rocket/spacegunconvent.php) has a page describing the use of nuclear devices to power kinetic energy weapons, ranging from shotgun charges shooting pellets at 100km/sec, shaped charge nuclear warheads shooting streams of liquid metal at .03 *c* and even Casaba Howitzers shooting streams of high energy plasma at .1 *c*. Nuclear weapons can also energize X-ray lasers. In theory, such weapons can be used against ground targets from orbit, but the political authorities will be very wary of getting to that point, since it will be too close to an actual nuclear attack. For the most part, I would see WWVI and WWVII to be much more subtle conflicts using deception, economics, propaganda, assassination, cyberwar and other tools to destabilize and demoralize an enemy (much like Russia did to Ukraine since 2014), meaning the actual use of forces can be devolved to supporting local malcontents, the deniable use of SoF units and the occasional incursion of conventional forces or artillery to make sure a difficult objective gets taken. Studying how the Russians operate in Crimea and Eastern Ukraine, or the Chinese in the South China Sea and you will get an idea of how different large scale conflicts between major powers *could* be in the future. [Answer] If either side has an effective [Strategic Defense Initiative](https://en.wikipedia.org/wiki/Strategic_Defense_Initiative) in place then conventional nuclear weapons will be useless against them. This could be a extensive system of ground or space-based anti-ballistic missiles, high-velocity rail guns, or anti-missile lasers capable of defeating even the largest of nuclear attacks with minimal leakage. The technology for this isn't too far off as all 3 technologies exist and are currently in use in the military. If a WW3 was impending one imagines that fortifying one's country with such systems would become a priority. Nuclear weapons would likely still be utilized on the front lines in various capacities, but we would not see a nuclear holocaust. [Answer] Here's a weird answer: over decades, all the nuclear powers are facing increased tension, slowly developing. Over the years, they gather to negotiate more monitoring of each others' systems, and each side implements more safeguards against accidental launches. The day comes that they go to war. Eventually, one side decides to launch, only to discover they've created such a beaurocratic and technical knot that no chain of command actually has the ability to issue the launch orders. They've given so much over to computer monitoring and that requires approval in triplicate to access that the missiles are totally inaccessible. The generals and techies may not have intended this result, but it just sort of happened because it was impossible to test an actual intention to launch. The only time they ever did practice runs was with the computers in test mode, which apparently works completely different from live fire mode, but no one realized that bug had been introduced. Digging the missiles out of their secure bunkers or creating a new control system will take longer than the war's duration. There's a lot of detail to work out around how the situation arose (and whether it was intentionally done by a clever diplomat putting specific requirements into various treaties), but I think it is a viable option. [Answer] Mutual Assured Destruction means that nuclear weapons are essentially a weapon of last resort: a way of saying "If I can't win, then neither can you". If you want WWIII to be non-nuclear, then you need to avoid situations where one side or another would be tempted to use them. * The war needs to start gradually (an escalation of a proxy war in the Middle East?) or formally (a declaration of war). A rapid start, and especially a surprise attack, will tend to cause the other side to respond with nuclear weapons. * Neither side should ever be in a position where it feels it's been "backed into a corner": no large-scale invasions of the core territories, and neither side has an obvious, overwhelming advantage. This is much easier if the opponents are on different continents. * The war needs to end through negotiations, and those negotiations need to leave the losing side in a position where it will clearly be worse off if it chooses to go nuclear instead. [Debellation](https://en.wikipedia.org/wiki/Debellatio) or unconditional surrender is right out. Basically, a non-nuclear WWIII would consist of an American superpower and a Eurasian or African superpower fighting, where most of the combat takes place in third-party territory (eg. Pacific islands), and ending when the losing side has been pushed back to its core territory and clearly can't continue fighting, but the winning side just as clearly isn't in a position to mount an invasion. (Another option would be North American vs. South American or Eurasian vs. African, with back-and-forth fighting settling down to a stalemate at a geographic chokepoint.) [Answer] I would like to expand on the last paragraph of Thucydides' already excellent answer. I hope this will allow you to understand better that the use of Nuclear Weapon in the next 'global war' is an unlikely as ever. The Russian operations in the Ukraine is a great example of how wars will be in the future. The days of countries openly and formally declaring war on each other and then proceed to prosecute that war with all the limitations imposed on the belligerents by any Laws of War such as the [Geneva Conventions](https://en.wikipedia.org/wiki/Geneva_Conventions) or things like the [Law of Land Warfare](https://www.loc.gov/rr/frd/Military_Law/pdf/law_warfare-1956.pdf) is fast coming to an end. This is mostly due to nation states' realizations that they have a lot more strategic and tactical flexibility if they engage in an undeclared hybrid war such as the one the Russian Federation is prosecuting in the Ukraine, Iran is prosecuting in Syria, and others. (For a comprehensive study of how Russia prosecutes this war please read [this highly interesting paper](https://prodev2go.files.wordpress.com/2015/10/rus-ukr-lessons-draft.pdf) by the Potomac Foundation.) 'Hybrid Warfare' or 'Non-Linear Warfare' or the Russian 'New Generation Warfare' is of course a term first popularized by GEN Valery Gerasimov, the CoS of the Russian Armed Forces in a paper titled [The Value of Science in Prediction](http://vpk-news.ru/sites/default/files/pdf/VPK_08_476.pdf)(linked article in Russian. [Here's a good translation](https://inmoscowsshadows.wordpress.com/2014/07/06/the-gerasimov-doctrine-and-russian-non-linear-war/).) According to Gerasimov: > > In the 21st century we have seen a tendency toward blurring the lines > between the states of war and peace. Wars are no longer declared and, > having begun, proceed according to an unfamiliar template. > > > He then continued to press his point in the most interesting, and important, paragraph of the article: > > The role of nonmilitary means of achieving political and strategic > goals has grown, and, in many cases, they have exceeded the power of > force of weapons in their effectiveness.All this is supplemented by military means of a concealed character, including carrying out actions of informational conflict and the actions of special-operations forces. The open use of forces — often under the guise of peacekeeping and crisis regulation — is resorted to only at a certain stage, primarily for the achievement of final success in the conflict. > > > This means everything from information warfare (agit/prop), the use of proxies (rebel groups, militia, irregular forces), the use of undeclared SOF (see [Little Green Men](https://en.wikipedia.org/wiki/Little_green_men_(Ukrainian_crisis))), economic warfare, the intermixing of GPF/SOF personnel in proxy groups (declared as 'volunteers'), the support of proxy groups by high-end kinetic capabilities (cross border artillery, UAVs, etc). The war in the Ukraine, Iraq, and Syria are nasty conflicts without a doubt. Anything from massed fire into civilian areas to the summary execution of wounded combatants were seen. What we do not see, however, is the use of nuclear weapons. There are basically four reasons why your country needs to deploy nuclear weapons: 1. To destroy concentration of forces. This is what NATO planned to do against massed Soviet armored formations if they ever storm the Fulda Gap. 2. To target the enemy's nuclear weapons facilities (the First Strike use to ensure elimination, or at least severe reduction of the enemy's capability to retaliate) 3. To target enemy cities. This was envisioned to destroy the enemy's will to fight. This is no longer applicable in the 21st century. No nation-state will ever deliberately target an adversary civilian population with nuclear weapons. Hell, not even with chem/bio weapons. The Syrian use of chlorine gas against rebel positions that happened to have civilians in it was a very different ball game to the deliberate US targeting of Hiroshima and Nagasaki. 4. And most importantly, based on the three above, to deter adversary aggression based on the threat of force. All these are nice and good if you're engaged in an open, conventional war with an adversary state, where combatants of both sides wear uniforms, acting under legal orders, and are bound by the Geneva Conventions. In a New Generation War? Not so much. The use of nuclear weapons are always a double edged sword. Yes, its massive destructive power will obliterate anything you hit. But on the other hand, anything it hits is no longer viable for extended operations. Even if your armies can operate in MOPP, they would not be able to prosecute effective combat operations for long. Their MOPP suits will quickly degrade their performance, use up supplies, and make the area unsuitable for staging. Moreover, it will alienate the using power from the population it seeks to either win over or cow, quickly limiting its ability to operate freely in its AO, making your armies devote too much time to Force Protection instead of offensive operations. It will also break the shield of deniability that the user has projected to hide their operations. Russia can deny the Little Green Men were theirs (until, of course, they admitted it), but if all of a sudden accurate, massed nuclear fire hit Ukrainian Army positions - well, you can't hide and deny that. So to answer your question: The way WW3 happens on your world without the use of nuclear weapons is to realistically portray the conflict as a series of interconnected low-intensity hybrid warfare prosecuted by several different governments, their irregular proxies, and various other non-state actors (Al Qaida, IS/Daesh, Boko Haram, Abu Sayyaf, etc) that take place around the globe at roughly the same time for a decade or even more. Its close enough to what we are experiencing right now that you can make the scenario very realistic. [Answer] To avoid a full-scale nuclear war, all you need to do is eliminate most of the people who know the codes which can launch the missiles. Any reasonable airborne pandemic can do that. Release a bio-weapon to knock off 40% of the planetary population. This will destroy most of our infrastructure and take out 4 out of every 10 people who know the codes. Then, as the millions of un-buried corpses rot and putrefy, additional diseases will ferment, killing off more of the population and contaminating the food and water supplies. Within a few months, only 10% of the original population will still be alive. With any luck, only 1 in 10 of the original code holders will make it this far. With so few survivors left alive, the few who know any of the launch codes will be too busy surviving to use them. Within a generation or two, those codes will be ancient history and the missiles will be a bunch of rusted relics. Now your growing population can get back to the time-honored art of world-wide warfare, without the threat of nuclear annihilation. ]
[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/36542/edit). Closed 7 years ago. [Improve this question](/posts/36542/edit) The mercenaries in question are all from the same species, have technology comparable to that of the human clients (us) but place little, if any value in human currency. By comparable I mean their tech is as advanced as ours, however it's too incompatible to barter for equipment, spare parts or fuel. Also due to their biology and preferred habitat (in this particular example I imagined an amphibious species capable of periods on dry land but eventually must return to an underwater habitat, if this helps any) trading medicines or foodstuffs probably would be out as well. What would we (or another species in hostilities against us) have to offer them? [Answer] Surprisingly there is in fact already real theory about interstellar trade. <https://www.princeton.edu/~pkrugman/interstellar.pdf> <https://en.wikipedia.org/wiki/The_Theory_of_Interstellar_Trade> An important point is that you would expect arbitrage between the 2 planets as long as there is something, anything, anything at all that the 2 want to trade. Once there's arbitrage you should be able to pay for services with simple money, either your own or theirs though probably at a steep exchange rate. As long as someone else is trading something, it could be some kind of raw material or rare metal, information like industrial methods or material science or services like humans performing some service. Perhaps they sometimes need to hire human mercenaries for desert warfare. The important thing to remember is that your protagonists don't need to find that rare metal, find the industrial methods or act as mercenaries themselves as long as some humans from their own planet are already doing that in exchange for something because at that point someone else will be trying to make money off interstellar arbitrage. Perhaps your aliens use crystals for money, doesn't matter. You'd be able to go to a human finance firms and swap Terran Union Credit Chips or whatever currency they use for the alien currency. Though almost certainly at an extortionate exchange rate. In terms of practical things humans could provide my first thought is that humans can operate pretty comfortably in deserts. I'm assuming low-scifi tech, think our tech level with spaceships, lasers and amazing gadgets but no nanotech or autonomous robots or infinite energy machines so that labor is still of value. Energy is pretty a pretty universal need for civilization. If their world has any deserts then they're going to be very very harsh on an amphibious species. Humans could set up deep in the middle of their version of the Sahara and build massive solar farms selling power to the frogs. I could imagine some of the aliens leasing areas of the ocean on human planets and farming/managing/mining the ocean depths where it's too too dark and too hostile for humans. [Answer] We would trade them things they want. This seems like a duh, because it is. As the story writer, it is your job to decide what it is they want. Technically, your question is off-topic because it's an idea-generating question, but I'll answer a slightly different question: "how do I determine what it is they would want for trading, given limitations X, Y, and Z?" There are two things to trade: goods and services. I suspect that some of the mercenaries will be collectors, happy to trade for "worthless" trinkets which are neat. By and large though I don't expect this to be the case. So you're left with services: things you can do for them. Some examples: If they eventually need to return to water, then they would be somewhat ineffective in space where water isn't particularly prevailiant. At some point, something's going to happen and they will all need to be back in water. What if they had somebody without that limitation to help them keep the ship in one piece while they're doing that? What if they trained somebody who could look after their non-aquatic ships and perform maintenance. Yes, their technology is different, but you could still learn to work with it. Furthermore, there may be some tasks which require hours of continuous monitoring - so they'd either have to work in shifts or have a non-aquatic person watch it. You could also learn to build things they need, thereby enabling yourselves to trade goods like you're used to. Anyway, there are some ideas - but the real answer is to continue thinking down this line of thought asking yourselves what kinds of things can you write into the world that they would want? [Answer] Something with intrinsic value that is also fungible and quantifiable. For beings across the universe, that will probably be energy. Mercenaries will need energy to run their spacecraft, power their weapons, supply the life support systems they use and so on. Anyone to anything they meet and interact with will also need energy in some form or other of do the things they want to do, so the mercenaries will need to have energy in a form which is rather compact and easily transferrable. What that form actually is is up to you. Batteries carry electrochemical energy in a fairly dilute form (which is why electric cars were displaced over a century ago and are not making a comeback regardless of what Elon Musk or GM say), but electrochemical energy is much denser and more easily handled in hydrocarbon form. Having alien mercenaries being paid in coal or oil is strange to contemplate, but quite sensible since hydrocarbons have energy densities 20-50X greater than battery technology. Order of magnitude higher energy densities are possible with nuclear energy, so you might pay your mercenaries with Uranium of Plutonium, or if they have mastered fusion energy, tank up their ships with D2 or 3He. If you are minting coins out of fissile material, encourage the mercenaries to use lead wallets and not to carry lots of change..... The highest possible energy density storage is antimatter. Assuming you have a reasonable means of either making or harvesting antimatter, you can provide energy in the most compact possible form (canisters of frozen anti hydrogen is possible with currently known technology, although we don't have enough anti hydrogen to really make this worth while). The issue right now is antimatter is made at such low efficiencies that *we* would go bankrupt trying to supply any reasonable amount to the mercenaries, and our current technology isn't up to long term storage or bulk supply handling of antimatter in the sorts of amounts that an interstellar mercenary band might want. Still, there is incentive to work on both antimatter production and storage technologies for our own use, and that might translate in the future as a means of interstellar payments. [Answer] * Sanctuary for their rear area troops, protected by our frontline troops. The fact that they're amphibian might help, offer them some [nice tropical islands](https://en.wikipedia.org/wiki/Diego_Garcia#Arrival_of_the_US_Navy) with the surrounding seabed. The deal is that they'd be under our SAM umbrella from the mainland and that they will patrol the waters. * Spare parts made by us to their specifications. They might not use [metric fittings](https://en.wikipedia.org/wiki/Tupolev_Tu-4#Design_and_development), but we can start a production line just for them. * Same for medicines. They give us a sample, we replicate it. [Answer] **Slaves** Yes, you read it right. We can offer ourselves (or humans that we believe are inferior) to that alien race, and even an enemy race can offer our people to the mercenary race. Why an alien race would need slaves? Let's examine two real cases: the Viking/Spartans slave system and the Atlantic slave trade *Viking/Spartan mode - We need to support a neverending war machine* You said that your amphibious race is a race of mercenary, didn't you? So, I guess that they hold in high esteem the maintaining of their military equipment, and training of all able-bodied men. The problem is that war is something extremely costly, not only in terms of lives, but also of time, energy and resources. So, how do you devote yourself to war, if there is no one who cultivates fields? The answer is: someone who does not participate to war, and don't use so many resources. The slave is perfect for this role. The Vikings had a polygamous society and perpetually devoted to war. So slavery was a very significant motivator in raiding. They captured women for themselves, men to work in the fields and to manufacture the tools that warriors would use. Even the Spartan economy was based on enslavement of an entire population, the Helots. The Spartans were fighting, and the Helots had to support them with their work. *Atlantic slave trade mode - We have resources, we have no manpower* Imagine finding a planet where there is already a native breed. The planet is very rich in natural resources, and you, the galactic conqueror, enslave the population to extract resources. Only the native race is weak. It is not used for forced labor. So you always have the same problem: how to exploit these resources if workers die? Discover by chance another race, whose people are in constant conflict with each other for trivial reasons, but they are physically stronger than the native breed. So you decide to take advantage of these reasons, and to enslave the enemy of a population of this race. You have your strong workers, and have them free. Now I imagine a situation where your race of mercenaries is not as belligerent as in the previous case. Perhaps the planet is rich in resources, but given the amphibious nature of your race, it is difficult to fully exploit them. Instead humans are adaptable. They always have been, it is one of their characteristics. Here they serve. Slaves can handle the extraction of native resources when amphibians can not. However, the use of slaves presupposes some requirements. Meanwhile, the labor force must be very economic. In our world, to use slaves rather than paid workers in the Third World is profitable because it is REALLY profitable. In the 800 cultures this distinction was not so clear, and that is why Adam Smith wrote that it was better to pay a worker rather than exploit it. [Answer] There's no telling what their biology is. It would be likely that any human medicine would have no value to them whatsoever, outside of studying it. This would mean it would have no trade value. The same goes for their technology: who knows what they use as fuel. So as far as trade value goes, the following would seem feasable: * Conductive materials: it is highly likely their technology needs conductivity, so conductive materials (copper, gold and graphite) could have a reliable trade value * Precious metals: titanium, gold and silver could have industrial use even to them. * Crystals: diamonds, graphite (also conductive) and other crystals could have value for their technology. Other than these functional trade items, human weaponry (possibly modified to be usable by alien bodies), human art and some commodities such as art could have value, but for real trade it would probably be limited to any functional recourses their planet might lack. [Answer] There are going to be two stages to trade. In the first stage you can pay them in ## Just about anything manufactured The novelty gives things value. A plastic model of a horse will be such an unusual item, such a strange alien creature than it will have, for a time, value on alien markets. Even photos of Earth, white clouds? a blue sky? way out man! Later as the market starts to saturate you'll have out actual animals for a while. Everybody loves invasive alien species on the black market. Eventually these things will lose their value as the novelty wears off and you end up needing something a bit different. ## Works of art These will probably turn out to be the ultimate in transferable trade goods on the interplanetary market. Art remains unique and special to a planet even if fairly basic, as it does for the various regions on Earth. Against a vast galactic population, works of art in a specific planetary style will always remain in limited supply. [Answer] Your problem is mass. Stuff like metals or anything manufactured is going to be heavy - meaning fuel. So you're after things that are rare or unique to your host civilization. They'll want fuel anyway - but they may have seeded your local gas giant with He3 refinery seeds on the way in - so you may not have that to sell. Information may be useful - but I can't see our science or maths being anything they wouldn't have already got. Psychology or Biology on the other hand could be valuable as science. Its possible we might have bacteria that might have industrial applications (e.g. metal extraction, specific fermentation products) that they might have use for - Bacteria aren't affected by the weight problem because they can replicate and be frozen pretty readily. But its likely that they already have that already either by microbiology or artificial nanotechnology. So its going to be art or music or fiction. All of which may not have any aesthetic value to an alien at all (but they could sell onto collectors or other races). Your aliens might like dolphin brain wave patterns, their art may not be understandable by us at all. ]
[Question] [ Watching investigative crime shows on TV, I got the idea of criminals developing and using guns with barrels that can be removed and replaced, so that even if the police find the murder weapon on a suspect, they wouldn't be able to match the bullets found in the victim's body to the weapon. Could this work? [Answer] **Yes.... Sort of** The problem is not with the concept - almost all Barrels are replaceable - Whether we are talking an LMG Quick-change barrel, an AR-style barrel that can be replaced at home with a few specialist tools or any other firearm. The reason for this is that a Barrel is a consumable part. That is - Barrels wear out. Depending on Calibre, Ammunition, care etc. an Average Barrel life is around 5,000 rounds. Most shooters aren't going to be firing that amount of Ammunition through a single Firearm, unless they are a competition shooter/Sport shooter or they take their training *very* seriously - a hunter might go through say 100-200 rounds a year on a particular rifle. Even then, a Worn Barrel unless you are going for precision at longer ranges or you are experiencing excessive blow-by due to increased windage - it's not very common. So this is the 'Yes' Part - you can replace the Barrel. The Sort of part is that TV Shows take real life Forensics and Hollywood-ize them - for example - when you see a 'Perfect Match' - Nope, doesn't happen. But let's for the sake of argument say that in your story/world it does - there's an even easier option: **Lapping the Barrel** This is used to clean the Barrel with a very fine grinding paste to remove tool marks from the lands/grooves/bore of the Barrel and to remove any Lead deposits - This process, done aggressively enough would alter the Barrel enough that it's no longer a perfect Match and it's much cheaper. [Answer] Small imprecisions in the inner shape of a barrel create imprints on the fired bullets which can be interpreted by forensic scientists. Other clues which can be analyzed are imprints of the firing pin on the firing cap, and DNA traces on spent cases. (A revolver would not leave those behind if it is not reloaded at the scene of the crime.) Present-day handguns can be disassembled into multiple parts, one of them is the barrel. The barrel can **already** be replaced, but the barrel ist a relatively large, relatively expensive part, and stamped with a serial number. So the barrel would not routinely be thrown away. What does that leave? * There are [frangible bullets](https://en.wikipedia.org/wiki/Frangible_bullet), designed for use against soft targets (read, unarmored people) in environmnents like aircraft. However, they might not come apart enough to prevent analysis when they do *not* strike a wall. * A couple of years ago, a German computer science magazine and a licensed gunsmith collaborated to test the plans for a [3d-printed gun](https://en.wikipedia.org/wiki/3D_printed_firearm). (I'm sure there were other tests, I recall reading that one.) Their assessment was that the first couple of shots did jam because the fitting needed asjustment, then a couple of shots worked, then it was worn out and ceased to work reliably. So, not a practical or safe weapon. One might come up with a gun design which has a disposable insert *inside* the permanent barrel. Currently such inserts are used to alter the caliber of a weapon, e.g. a single-shot hunting rifle. They are not disposable and the weapon is *normally* used with the regular barrel. The variant would be designed to work *only* with an insert in place, and to feed ammunition from a magazine. * A more futuristic option might be a [saboted bullet](https://en.wikipedia.org/wiki/Sabot_(firearms)#Expanding_cup_sabot) with sabots which come apart after firing in a way that prevents analysis. The challenge, here, would be that they must be rugged enough to last during the firing, so they cannot simply burn up. Materials similar ot a frangible bullet? * One could, obviously, use a shotgun with pellets to avoid bullet rifling. There are shotshells for some common handgun calibers, but they tend to damage a rifled barrel. [Answer] **Calibre Conversion Sleeve** What you want is actually something that alters the calibre of the weapon and can be removed easily. See the [Calibre Conversion Sleeve](https://en.wikipedia.org/wiki/Caliber_conversion_sleeve) You slip in the converter into a larger calibre weapon and remove it when finished. [Answer] As most have already stated, there aren't a wealth of firearms in this modern era that don't have replaceable barrels. Some are harder to remove, but a competent gunsmith could handle those. Most, like a common glock, for example, require no special tools. You can pick up a spare barrel at a gun show in cash and leave no trail back to you. If you are writing a story and need something like this to throw some detectives off your case, you may instead want to consider the numerous ways a firearm can be purchased legally without any paper trail leading back to you at all. As O.M. pointed out in the comments, why not just have a separate gun? Well, the mob did exactly that all the time. Cheap, single use snubbies that ended up in a river after a murder were practically textbook cliche. Ok, so where do you get them? Gun shows for one. They are practically a monthly assembly in the southern red states in the USA. Park a few blocks away, use cash, wear a sun hat, and blend in. Wait a while before your mission, and it may be very hard to track this purchase down. All gun show purchases I have made or known about have been completely absent of paperwork. Armslist.com - they have changed a little as of covid, but back in the day any idiot could post a listing to sell their guns privately. I bought a couple brush hunting guns from people on that site and neither one of them filled out a bill of sale or even looked at my ID. Nowadays you have to pay to post or see listings, but people can get around that by putting their phone numbers in the pictures that you can see for free. So if your story requires someone who MUST acquire a gun without trace, and the type doesn't matter all that much, you can have them hunt the listings there (incognito from an internet cafe) till they find what they need that happens to have a phone number and then they can use a burner phone to text the seller and transact. If they go down the bill of sale road, then your character needs to shelf that gun and look for the next until they encounter someone who forgets to do the paperwork part. It is more common than you might think. Estate sales. Many people just sell off inherited guns without knowing or caring of the expected protocols. You're supposed to get a bill of sale with the purchaser's info on it, but few do that. If you have ever heard of people reciting the line "close the gunshow loop" - this is what they refer to. The loophole that says any private sales of guns need not go through the background check system. FFL holders have to play by the rules but private parties don't. Mail order barrels - You can buy barrels online. This will leave a paper trail, but not one in the gun registry. Buy a barrel, swap out your original, commit a crime, swap the original barrel back in the gun, CHANGE AMMUNITION, then go out to the desert and shoot a couple hundred rounds into some cans so you build up a wealth of powder residue that matches the changed ammo, and leave it uncleaned till the cops come a knockin. When you hand over your gun, those barely adequate comparison tests will have just too much out of place to consider it a match. You may not avoid the suspect list, but you probably won't be taking top billing if played right. That is, till they realize you bought something from Bo and Luke's gun ranch a year ago and their catalog clearly shows barrels for your gun. Then they piece it all together and haul you away because they are detectives and they know of these tactics. Still, could be done this way if you were smart enough about masking every bit of info and internet gateways you use to orchestrate this. Also, if they use a ghost gun, their top priority after the crimes would be to fully dismantle the pieces and scatter them across as much land as possible in any way that could not result in the pieces being identified. For polymer guns, you can remove all metal parts and simply burn the polymer parts and mix the goop and ashes into a colorful mosaic flower pot. The barrel and the slide might have to be baked into a brick and laid out in a garden wall or tossed into a land fill. Probably many better ways to get rid of the parts, but I'm just throwing out basic ideas here. I've never actually tried to completely dispose of a gun, but I have dismantled them down to every last piece. So while this doesn't directly respond to your question about barrels, it does explain much easier ways to achieve effectively the same thing. Why don't criminals do this? Because they are unaware of these loopholes, too poor to willy nilly buy guns in secret from websites, or just don't have the brain power to think things through. I mean, until some idiot posts about it on the internet and fills their murderous brains up with info we'd all prefer they don't have... feel free to delete this post if you think it is too much info. [Answer] ## You’ve just moved the goal posts Instead of “how do I dispose of this gun”, the problem becomes “how do I dispose of this barrel”? I’m not sure that this problem is any easier to solve. Also, virtually all guns have interchangeable barrels (within the make) already. [Answer] Just print the barell in situ and throw it away? Difficult. Reboring a rifle is very usual process. Could be done right after the crime and all traces would be gone. Best? Never have the projectile interact with the barrel, beyond the gas-sealing effect. Just put the bullet on two rails, with the gas sealed by a ejectable and burnable sledge-cartridge. No contact, no traces, just acceleration. [Answer] We already have 3D printed guns. I won't google it to get onto some watch list somewhere, but there is regular murders here with 3D printed guns. They sort of look like flare guns. And they still catch them, even when something as simple as a microwave can destroy the printed gun. So the answer is it works, but you didn't solve the problem. ]
[Question] [ So in my seting an alternate universe that's 67 million years "behind" ours, T. rex is on the brink of extinction early, with only 1 member left due to extreme overhunting by universe traveling humans. An organisation needs to find this last living, breathing T rex in order to create clones that can rebuilt the decimated Laramidian ecosystem. They can't use poached materials (like luxury T rex handbags) or dead individuals collected for science, because the universe traveling distorts the DNA of dead and dying organisms (but not living ones) and the infrastructure doesn't exist in the cretaceous human settlement to do intense genetic research. Does this all check out? [Answer] DWKraus has an [answer](https://worldbuilding.stackexchange.com/a/233646/2252) rooted in science fiction: Maybe only a T. Rex egg can be used to grow a baby T Rex. As it turns out, we can make the same argument rooted in [science fact](http://scienceline.ucsb.edu/getkey.php?key=3425): > > To answer your question, it does not appear to be possible to insert the somatic nucleus of an animal into the egg of an animal of a different species and generate a live clone. The reason for this is that development of an embryo is an incredibly sensitive process even in regards to naturally occurring fertilization. When an embryo initially begins to divide, many proteins present in the egg are responsible for ensuring that cell division occurs properly and that those cells begin to express the correct genes at the correct times > > > For present day cloners, your concerns are reality. [Answer] # You need a female T Rex to grow T Rex eggs: No other species than a T Rex can grow a T Rex egg in its body like a T Rex can. All the genetics in the world don't give you a species that produces T Rex eggs that will work as well as a T Rex. Even if your more advanced science could allow you to Jurassic Park an egg from another species, there are innumerable ways the real egg would work better. Differentiation in non-reproductive cells will also mean that many regulatory signals and steps would need to be undone and “de-differentiated” which might work with more advanced tech, but which today we can’t even do with species we understand much better. There's also a lot we DON'T understand about dinosaurs, that we may never know, since we can't study their direct biology. We have birds and reptiles, but maybe they don't accurately reflect how the dinosaurs really grew. Our deep ancestors could (we believe) see color, but because of an evolutionary bottleneck, all our direct ancestors were small mousy creatures that were color-blind. We have a completely re-evolved color system. The same could be true for the T Rex. Their immune system could be involved in causing their eggs to harden enough to protect the contents. Or perhaps we don't understand some critical step of temperature control in the incubation process - something the female T Rex understands instinctively. Or there is something unique about T Rex tissue - it's full of DNAse as a protection against ancient viruses that no longer exist, and all the DNA is rapidly broken down once the T Rex dies. But fresh tissue is essential to get intact DNA. [Answer] **Clone-quality DNA requires preservation.** Real-life cloning projects use either fresh samples or specially preserved specimens that are usually frozen. A long-dead biological specimen might have degraded DNA that makes it unsuitable for cloning. Unless someone has a sample that has been specifically preserved in a manner suitable for a cloning project, you'll require a living organism to collect a viable sample. [Answer] Meet the [thylacine](https://en.wikipedia.org/wiki/Thylacine). We have plenty of thylacine specimens; the species went extinct at a time when museums were keen on preservation of endangered animals, and had no qualms in instructing hunters to endanger them further if it would bag them a pickled Tasmanian wolf. And yet, various [cloning projects have failed](https://web.archive.org/web/20081015173047/http://www.abc.net.au/news/newsitems/200502/s1303501.htm), on account of: * the preservatives used to store their tissues (formaldehyde, ethanol, etc) degrade DNA and/or make it impossible to extract * you need a mother thylacine, for developmental reasons already addressed by other answers * even in ideal circumstances and with a surrogate mother, cloning is just quite difficult - [Dolly](https://en.wikipedia.org/wiki/Dolly_(sheep)) was the only survivor of 277 attempts. We've got better, and in some species there are reported clone survivorships over 50%, but these rates are obtained after *extensive* optimisations by trial and error, and with a conspecific mother. In any case, one successfully cloned T-Rex (or a battery of them) a genetically viable population does not make, let alone an ecosystem-saving silver bullet. Do you want a justification for a T-Rex hunting story? Or is the focus on the actual ecological mission? If the latter, you really have to rethink your parameters. If the former, find another motivation for your characters. ]
[Question] [ [Homo Erectus](https://en.wikipedia.org/wiki/Homo_erectus) is one of the oldest of the Homo species that went extinct 100,000 years ago. Let's say that Homo Erectus made it to Australia and was isolated on that continent until British colonization. Let's also say that the Homo Erectus were able to quickly copy the military technology of the British. What advantages would a Homo Erectus have also a Homo Sapiens in warfare? Homo Erectus were generally taller than the average person today which would lead to a reach advantage in melee combat. They also had thicker skulls than humans which would mean head injuries are less debilitating. On the other hand, their brains were generally smaller than humans which could mean they aren't as effective at war strategy. [Answer] # Advantage: *H. Sapiens* Seems crazy, but consider that weapons are a force multiplier which lets the basically unarmored person contend with lions and tigers, which are some of the best killing machines made by mother nature. The differences are not extreme enough in comparison to things like logistics, fighting techniques, and overall strategy to matter. I bet similar wounds bring them down as easily as us. They have no horns, no meaningfully thicker skin, no bone plates... Nothing in the *h. erectus* body screams "major advantage" over your average *h. sapiens* and reduced mental capacity is too much a disadvantage. # Reach and Strength Helps Only a Little As a HEMA practitioner and mostly average man, I have *literally* crossed swords with people larger and smaller than myself. Advantages in size and strength matter most for *grappling*, but can be counteracted by technique and speed. The extra height (if any- see question's linked wiki page) and strength may result in stronger blows, but not *that* much stronger. Some *h. sapiens* skilled in fighting, either as a unit or individually, can use their weapon(s) just as easily against a *h. erectus* as a *h. sapiens*. Strength, of course, becomes nearly negligible when talking about firearms. Guns and cannon are just so strong and damaging that all members of the *homo* family would die equally well from these. That's the advantage of not using muscle to power your weapons. # Brains Help A Lot Using the assumption they are worse at tactics than humans, but not overall strategy and logistics, this gives the advantage to a unit of *h.sapiens* over *h.erectus*. Things change when fighting as a unit, which requires discipline and coordination. You need to recognize when your buddy's man is open and strike them when they are preoccupied. Alternatively, knowing when to stand ground and defend the musketeers is more important than making a hole in your line looking for a kill. Ultimately, coordination is more important on the unit level than individual capability. Assuming *h. etectus* is worse at logistics and strategy, then they will generally lose to *h. sapiens* in war. The capacity to stay organized, fed, clothed, and armed does more to ensure victory than individual efforts or a big battle. Being at the right place and time to cut off and weaken an opposing army is why you get generals! This has (and may always) be true throughout human history. Hungry, cold, and/or outnumbered solders don't fight well in spite of their peak ability for violence. [Answer] Copying the military technology of the British is insufficient. The British had thousands of years of evolving military strategy and weren't hunter gatherers. They'd just do what they did everywhere and arm one group of natives to kill the others. The other problem is natural resources, Australia is poor in natural resources. Knowing how to make a gun is useless without the materials to make it with, or the gunpowder to power it. Or even the material to make the tools to begin making the gun with. So in terms of science everything from geology to advanced metal working, to chemistry is needed. The bright side of the coin is that Australia is not particularly hospitable. The English would go no further than the coasts for a while. Going inland is only worth doing if you have a bunch of convicts to unload. Physically I would expect them to be stronger and fitter than humans. That may not save them from wholesale destruction due to introduced diseases. That happened to many Pacific Islands who were in a position to resist colonisation before disease wiped out most of their populations. Socially they don't stand a chance. Hunter gatherers have never won long term. Their social structure makes them more likely to move into marginal areas and self terminate slowly rather than fight to the death. They have no overriding stake in the land they happen to be standing on. No crops in the ground to tend. Their lifestyle precludes maintaining large forces, especially in Australia. They'd just run out of food. Groups would be forced into other groups creating conflict over resources and it would be bloody chaos. If you want them to win, give them a disease which is relatively harmless to them but deadly to humans. Europeans depopulated whole Islands with the measles. So it could work the other way around as well. Your homo erectus could then just enslave the survivors and take all their technology. Any armies sent in would meet the same fate. This could even end with the homo erectus farming and shipbuilding and then taking over the World from homo sapiens through invasion. [Answer] # Little difference While *H. erectus* typically lived under primitive circumstances, the same is true of *H. sapiens*. The average difference in brain size proves very little. I'm in no mood to follow the footsteps of those who argued for differences between races and sexes based on brain size numbers; the facts didn't bear them out. *Conceivably* the reduced cerebral cortex, which provides a sort of map of the world of motion and sensation, might mean they had less ability to speak or manipulate objects in their fingers, but I don't know that. If our sort of humans lost books, oral stories and culture and were 'rebooted' from some machine-isolated children, I think we'd be worse off than *H. erectus*. The genome of *H. erectus* isn't known, but I'd wager it explains the reason for the lack of substantial hybridization with humans: there are random genetic features, such as inversions or differences in chromosome number, that simply stop two populations from being able to produce many fertile offspring. A handful of genes might get across through the rare exceptions, but the populations can simply be forced apart this way, perhaps in response to selective pressures ("sympatric speciation"). We have reason to believe *H. erectus* used fire, wore clothes, even crossed between islands by boat. While models vary, I think most say *H. erectus* lived along more "modern" species of human for a *VERY* long time, something like half a million years! It's hard to believe that competing species could live side by side that long if either had any meaningful advantage at all. They would be natives of Australia and know the ecosystem. That isn't sufficient if invaders come with guns, germs, and steel; but the premise in the question is that they copy the invaders quickly. I'm thinking they can hold on pretty well. [Answer] I'm not sure you quite understand the colonization of Australia by the British. Don't think US/South Africa where there were troops stationed all over the place conquering vast swaths of native populations. As is well known, Australia started as a penal colony, meaning it was mainly full of convicts plus a few soldiers to keep the peace. The first 4 years were dedicated fully to staving off starvation, as the "colonists" included hardly anybody with practical skills surviving such as farming. If your homo erectus attacked during this time frame, they might be able to overpower the British, but it mainly depends on the erectus population size. Additionally, as seen in the Americas and Australia itself, the main threat to the natives is disease. European diseases ravished native populations leaving them at partial strength. An estimated 70% of native populations died of smallpox in Australia. Maybe homo erectus could be immune to the diseases to help your story. If there was no major offensive until after the Napoleonic Wars, it's probably too late for native populations to hold off the British in the (modern day) Sydney region, but Australia is a *big* continent. There are plenty of areas in Australia still barely settled, and going back 200 years that's obviously even more the case. Maybe they could have blocked European settlement in far-flung areas such as the Adelaide, Perth, or Darwin. The most likely outcome for homo-erectus is the same fate as Indigenous Australians. [Killed mainly by disease](https://www.nma.gov.au/defining-moments/resources/smallpox-epidemic), [slowly pushed out of their territory by the British, killed for sport because they were seen as sub-human](https://www.theguardian.com/australia-news/2019/mar/04/the-killing-times-the-massacres-of-aboriginal-people-australia-must-confront), and [kidnapped from their parents](https://publicintegrity.org/accountability/longtime-australian-policy-kidnapping-children-from-families/). I don't see any big advantage homo erectus would have over Indigenous Australians. [Answer] Homo erectus may have looked like humans, but they had only half our brain size. Their intellectual capabilities can be assumed to be halfway between chimpanzees and us. They could only make simple tools and probably could not talk. They certainly used sounds for communication, but more like other primates do, not in the sense that they could relate thoughts or plans. They used fire, but it is not known if they could make fire. They did not leave behind any signs of art or anything you could call culture. In other words, they did not yet display what paleanthropologists call "**behavioral modernity**". Their life style was in many respect that of a very smart animal. They could neither copy military technology nor strategy. They could survive if the British (or any other society of homo sapiens) allowed them to survive. ]
[Question] [ For the purposes of this question: 1. The species is multi cellular and from an animalia like kingdom. 2. Sex is only physically possible when 3 individuals of all 3 sexes are present together. With only 2 members, sex is neither possible, nor enjoyable. 3. Fertilization is only possible when at least one sex orgasms. 4. An individual cannot spontaneously change its gender. How would such a system work, a) physically, and b), at the cellular level? (we need three different types of cells: sperm, egg, and ???) [Answer] Asimov described a similar system in his work "[The God themselves](https://en.wikipedia.org/wiki/The_Gods_Themselves)" > > The latter have three sexes with fixed roles for each sex: > > > * Rationals (or "lefts") are the logical and scientific sex; identified with masculine pronouns and producing a form of sperm. They have limited ability to pass through other bodies. > * Emotionals (or "mids") are the intuitive sex; identified with the feminine pronouns and provide the energy needed for reproduction. Emotionals can pass freely in and out of solid material, including rock. > * Parentals (or "rights") bear and raise the offspring, and are identified with masculine pronouns. Parentals have almost no ability to blend their bodies with others, except when helped by one or both of the other sexes. > > > All three 'genders' are embedded in sexual and social norms of expected and acceptable behavior. All three live by photosynthesis; whereas sexual intercourse is accomplished by bodily collapse into a single pool (known as 'melting'). Rationals and Parentals can do this independently, but in the presence of an Emotional, the "melt" becomes total, which causes orgasm and also results in a period of unconsciousness and memory loss. Only during such a total "melt" can the Rational "impregnate" the Parental, with the Emotional providing the energy. Normally, the triad produces three children; a Rational, a Parental and Emotional (in that order), after which they "pass on" and disappear forever. In the past, some triads have repeated the cycle of births (thus ensuring population growth), but the declining amount of solar radiation no longer allows that. "Stone-rubbing" is a practice of partially melting with solid objects like rocks, possible for Emotionals, but the other genders are only capable of it in a very limited form. It is an analogue of human masturbation and generally frowned upon. > > > At cellular level you can think of it like two sexes providing the genetic material while the third one providing the cellular protoplasm where the genetic material can operate. Since the protoplasm also contains genetic material (mitochondrial) it ensures the passage of the genetic information of the third sex. [Answer] The Culture series novel “Player of Games” describes such a species. In it, they describe three genders: male, female, and “apex”. The male and female are biologically just that, they provide the egg and sperm. What both male and female lack, however, is the womb to carry the growing new person. Sex works by implanting sperm and egg into the apex. All three are fully required. Interestingly, in this society, both male and females are considered lesser than the apex gender, in a highly stratified and sexist system. I will note that making sex unpleasurable without all three present is a tricky thing to consider… after all, we have two sexes and it’s still plenty pleasurable to simulate sex while alone, and homosexual sex is pleasurable to those who like it. Restricting pleasurable sex to all three would likely require a mental component, similar to how truly heterosexual humans simply do not like to engage in homosexual relations. Alternatively, the pleasure in sex could involve something like an electrical feedback loop. Our pleasure from sex comes from stimulation of nerves, but you could imagine a species that actually requires nerve ending to touch with another gender’s nerve bundle to be pleasurable. You could also extend that to requiring the third gender as well for the nerve bundles to work, possibly involving an internal feedback loop of sorts, such that lacking any of the genders breaks the circuit. [Answer] # Mendelian Genetics: Your genders are based around a not-so-simple but still [Mendelian inheritance](https://en.wikipedia.org/wiki/Mendelian_inheritance) of chromosomes. There is one trait, and each gender can be AA, aa, or Aa. 50% of offspring are Aa, and these are an intersex gender. The AA and aa together each contribute an (A) from the AA and an (a) from the aa. All The Aa contributes an (A) or (a) to each conception. Twins are born, genetically different. You can have a quadraploid conception, or you can have two conceptions with each pregnancy. With two separate conceptions, the Aa individual might potentially produce two different kinds of sex cells, one compatible with the AA gamete, one compatible with the aa gamete. All contribute genetically, and if there are no aa or AA individuals, conditions are considered too extreme to allow reproduction. Thus this three-gender system is a safety check on when it is safe to reproduce. This is kind of complicated, with the accompanying disadvantages of complexity, but with the quadraploid conception, you may potentially have [recombination](https://en.wikipedia.org/wiki/Genetic_recombination) occurring between all four sets of chromosomes. All offspring could thus potentially have genes from all three starting parents. Thus the possible number of diverse offspring is significantly increased over conventional reproduction. The social roles for your system are up to you, but I would suggest the Aa's are the worker ants of society. They make up the largest part of the potential labor force. Without at least one worker available to support a child, it is unsafe to reproduce. The mechanism of the biology has two main options. The 'host' option (already presented in another answer) has the Aa intersex individual functioning as the womb for the other two sexes. The 'catalyst' option (presented in [Alien Nation](https://en.wikipedia.org/wiki/Alien_Nation_(TV_series))) would have the intersex individual somehow needed to stimulate one or both of the other genders. The pleasure may come from the release of the catalyst, which only occurs when both other genders (AA and aa) are involved. There is likely a strong social aspect to this sex, where an Aa must feel safe and (dare I say) loved. Such a system suggests an environment where there are long periods of relative good reproductive conditions, followed by periods of intense selective pressure. The high diversity allows at least some individuals with especially advantageous combinations of genes to survive the harsh times, while the good conditions allow the more complex reproductive scheme to be less of a disadvantage. [Answer] You could delegate the pheromones' or hormones which cause the male and female members of the species to want to reproduce to a third sex - so the men and woman would neither have the desire to reproduce without the third sex being around. Two variants of this. Either the third sex puts off the pheromones constantly so they just need to be around to get the first two sexes in the mood or the third sex may only put off the pheromones at certain times of the year or when its found an (evolutionary-wise) safe place to rear the babies. [Answer] I'd go with two types of males (sperm producers) and a female (egg producer). Give them physical characteristics to distinguish them. The two types of male are each only capable of producing half the DNA required to fertilize an egg. The only way reproduction can happen is if all three orgasm; the two males must ejaculate inside the female; and only once the chemical signals are present to indicate the possibility of pregnancy, then the female is capable of orgasm. If an egg is available for release, the orgasm will cause it to be released, so it may be fertilized by the two types of sperm. Unlike humans or other mammals, the eggs do not drop on a time schedule or cycle. For evolutionary reasons, they are preserved in the egg producer. But like humans, much can go wrong, intentionally or otherwise. Say the two types of sperm can both fertilize the egg, but if two of the same type of sperm fertilize the egg, nothing happens. So there is only a 50/50 chance of pregnancy. Intentionally, birth control may be possible; in any of the three genders. Say the chemicals that signal a type of sperm is present are not in the sperm itself, but in the ejaculate, the fluid that carries the sperm. And it is possible, by chemicals or surgery, to prevent any sperm from mixing with the ejaculate. Likewise, just like female birth control now, chemicals may prevent the egg from being released even if the female orgasms. And scientists may be able to synthesize the chemicals in the ejaculate as a cream or lubricant, so females could orgasm with the aid of any males. The male psychology would evolve to welcome the other type of male in sex and pregnancy, it would seem natural, and the female psychology would likewise evolve to be primarily sexually excited only when both types of male present. Sex with only one type of male present would seem weird and incomplete, to both males and females. I think you could build up a culture around this. ]
[Question] [ 150 years into the future, a space faction is in a confrontation with a stronger rival. Our faction is a Kardashev Type I civilization and has a similar technological level to its rival, but the rival is at least 0.1 higher on the Kardashev scale. Both of the confronting factions are defending their systems very well, and they have both realized that there would be extreme difficulties if they tried to siege their rival's systems. Under these circumstances, our faction decided to send Von Neumann probes to other planetary systems to establish new bases there. **Edit:** These probes do not require a supply of raw materials to build the base. (At most, they will bring a small amount of refined material for initial use.) They extract all materials locally. **Edit:** The bases will be entirely unmanned. There is no need to send human personnel to the bases once they are built. So we don't have to worry about any passenger ships being detected. However, the chance of such a probe mission being successful depends on the following factors: * For every location where we can launch an interstellar probe, our rival has several positions(planetary systems) within ten light-years distance, from where they can monitor our activities. * Our rival has anticipated that we may try to send Von Neumann probes, so they have put a large amount of energy, resources and computational power to track our interstellar launching activities. They have hundreds of thousands of observatories in each of their system, dedicated to watching our activities. These observatories cover all electromagnetic radiations from gamma-ray and X-ray to radio waves and microwaves. * Each of our rival's planetary systems can analyze all the data they collected from the observatories within that system in near real-time, but they only have lightspeed communication between their systems (so do we). Despite the slow communication, neither we nor our rival has internal conflicts. * The lightest Von Neumann probe we can make weighs 170 tons. We can split our probe into smaller ones that we can launch individually, but this does not decrease their total mass. * Our probe should be moving at a speed of at least 0.1c, and must not take more than a few years to accelerate. Otherwise, it would be too slow to make a meaningful impact on the confrontation. * Our probes must be able to decelerate when it approaches their target systems. (There are no existing infrastructures in these systems.) * **If our rival detects our probe during its acceleration, the mission fails.** Preferably, our probe should also keep undetected during its interstellar coasting and deceleration. So the question is: **How does our faction launch its Von Neumann probes without its rival detecting them? Is it possible at all?** Note that every technology and military operation of the two rivalling factions must work according to the laws of physics we know today. [Answer] ## Antimatter Rocket and Magsail Breaking Space is huge. A probe is tiny. Use stealth materials for the probe. Let the exhaust go into a direction where there are no enemy observers. Slow down with a magnetic sail. The probe will accelerate rather slowly and will use directional radiators to deal with the drives waste heat. It is probably worth it to build the probe in a Kuiper, Oort or even interstellar location. Either a comet or an asteroid. Deliver the seed package via stealth vessels, which where dropped from torch ships in the inner system, preferably on the far side of the sun from the enemy to throw of their sensors. Sundiving will be hell on the vessels but is should mess with sensors. Alternatively circumplanetary mass drivers on eliptical Orbital Rings or your usual interstellar launch systems could be coopted. No matter the exact technique, you either have to launch from where they don't look as closely to or use existing systems to launch something that looks normal, but isn't. Another idea to use Von Neumann probes would be to launch them away from the enemy and to develope strategic depth by colonising yourself out of the situation. You could also order them to turn entire solar systems into weapons. Systems that are far away enough to be more useful in a second strike capacity. [Answer] **Mechanically accelerate the probes.** [A look into railgun physics and design](https://scholars.carroll.edu/bitstream/handle/20.500.12647/3409/HarmonSFinal_2011.pdf?sequence=1&isAllowed=y) > > Railguns, however, do not have these limitations. Since the force on > the projectile is proportional to the current applied, there is no > theoretical limit to the amount of force applied to the projectile. > This means the maximum range and velocity are without theoretical > limit. Of course, due to the presence of atmosphere, gravity, > friction, and other forces, limitless force is impossible... > > > Your people have a very long space railgun fired by a capacitor. They have overcome problems of friction using magnetic levitation and superconducting rails. With the railgun they can accelerate the probes to the desired speed within the railgun. Probes leave the system travelling at speed. Once en route the probes maneuver as necessary by release of compressed gas jet. This gas is cold, as is all gas released from compression and so has minimal heat signature. This is outside the range of the OP but also important: slowing down. Excess velocity is shed on arrival via gravity assist with the star, aerobraking and then explosive jettisoning of materials needed for interstellar travel. [Answer] **If nano tech is available(?).** You covered pretty much all of the bases, so the only thing I can think of is, to deploy small swarms nanites into the systems Ort Cloud / Kuiper Belt. Each swarm is tasked with building components of the Von Neumann probes. and are instructed to build them within existing asteroids / comets etc to shield them from detection. Saturate the system with these swarms. each nanite would be nearly impossible to detect, detection is more probably after construction has started. But if they find one, there's still more somewhere. They will expend a great deal of resources to weed them all out, and there is a high likelihood that some will still get though. [Answer] # Distract their sensors The distance is pretty huge. While at that distance they could detect the immense amount of power needed to accelerate over a hundred tons to 0.1C, that would be much harder if their sensors were distracted. Build a massive number of lasers and fire them at the solar systems monitoring you. The heat and light will make it much harder to spot the acceleration among the messy signals. [Answer] **Mimic the signature of high energy particles** The different planets of interest are bombarded by high energy cosmic rays, gamma ray bursts or other natural phenomenon. Given the advanced tech, they know where a bright source of natural particles and the statistics of the particles that are leaving the source, so they add in a few more from that direction that have a similar signature. If the natural source is something like a pulsar, or jet caused by something falling into a black hole or some other high energy process, a few tetra watts giving the probes energy can hide in the high energy background. [Answer] **Johhny von Neuman's Flabberghasting Probuliser** [![enter image description here](https://i.stack.imgur.com/Stz5t.png)](https://i.stack.imgur.com/Stz5t.png) What is a Neumann probe made of? I will tell you now my friend -- the probe is made of smaller probes. Once daddy probe reaches full speed he separates into a cloud of baby probes that scatter over a few hundred million square kilometers. Baby probes are much harder to detect and they can talk to each other to blend in with background particle flows. When all the baby probes reach the planet they reorganise into a town centre which you use to build Villagers: [![enter image description here](https://i.stack.imgur.com/kHsnb.png)](https://i.stack.imgur.com/kHsnb.png) The Villagers say *Prostagma* and start chopping down trees and mining gold and build a colony under your enemy's nose. [Answer] I suggest laser propulsion for the acceleration phase. The reason stealth is hard when accelerating is waste heat. Any method of propulsion will produce lots of it, and heat is easy to detect. However, with laser propulsion the power source is not on the probe but in your solar system, and hence the waste heat will be generated there. Since you're on the Kardashev scale you're already generating many terawatts there all the time, so hopefully the extra power for accelerating the probes will get lost in the noise. This does require that you can make a perfect mirror, so that all of the incoming laser light will be reflected by the probe (be sure to aim the reflected beam away from the enemy!), with only a negligible amount heating up the probe. That requires some kind of mildly unrealistic future-tech, but maybe you can handwave it with superconducting meta-materials or some such. On the other hand I don't think you can avoid detection while decelerating, so forget stealth at that point and just decelerate as quickly as possible using whatever you have available. Then you have twenty years or so to build the biggest base you can. (Ten years before you're detected, and then another ten years after that before anything can reach you.) [Answer] # Sneak in with other celestial bodies Detection is one step, identifying another. You want to reduce both as much as possible. Detection can be difficult to fool. Space is big, but it's also empty. Our current methods can detect a wide range of small objects throughout our solar system! That doesn't mean it's perfect. There's plenty that is too dark and difficult, if not impossible to detect. A comet from deep space can easily blindside us. Recently one was noticed only after it passed us. Your civilisation will be much better at it. Better technologies and more distributed places to detect from will make it much more difficult. Still it is possible to try come in from unexpected angles in the solar system. In addition, be as cool as the space around it, don't let any electromagnetic radiation like light reflect off it and don't move too fast to disrupt gravity even more with the weight. Even with these measures preventing identification is your best bet. A stealth probe can still stand out. A stealth probe might be identified as a probe just because of it's unusual stealth characteristics. Make it look natural and you'll get much further. Embed the probe in a natural phenomenon. Though you mught think to embed it in a known comet that comes along every so often, it's weight and characteristics are probably too well known. Unexpected celestial bodies happen frequently though. Throw an ice and rock comet from deep space. The trajectory will take it into a solar system. Because of the sun and gravity of planets it can start breaking up a bit, shedding rock and ice. This can be seen as a dust trail of a comet. Some of it might come close to a planet or moon, crashing down on it. The probe itself is hidden in a rock and ice shell, making it look like it's just a random iron holding piece of debris. To navigate it must use a 'mechanical' means of propulsion. Simply throwing a part of the rock away while a long distance from a planet will give the right trajectory. This way nothing can identify obvious rocket trails. The probe uses the rock as a heat shield if going into an atmosphere. Landing is difficult, but maybe the probe is good enough to just crash land. If not, you might have to break the illusion there. So close to the target it might already be past any real scrutiny of the enemy, as they mainly focus further afield. In addition, the planet or moon might give off enough interference. The only problem then is launching it. 10 light years is a big distance, but soace is so much bigger. Go even further to setup and throw a bunch of rocks in the right direction. It will take a long while, but it's a sure way you can get a van Neuman probe past the enemy. You might hide it by sending out mining parties in big numbers, mining many asteroids. This is something suggested in RL as well. That means they can move within the detection range, but send out a probe towards a good rock away from the mining operation. Using the miners speed and just detatching the probes can be enough to get them where they need to be. If even that is difficult they can launch the whole rock formation themselves. It'll be dark and hard to spot, and using mechanical propulsion, trowing part of the rock out, they can change direction and come from an unexpected side, making it look independent from the mining operation. [Answer] # Flechette Launched Probes and some Deception Launch a tubular object that contains thousands of tiny Von Neumann probes inside of it. When it enters the system, shoot the probes (inactivated) in a mist towards the target area, using electromagnetism so there are no emissions or heat signatures. Then, the enemy will certainly have captured the launcher, wait a few weeks and activate the probes to begin clumping together. Set them to work on an uninhabited celestial object, and bam, you have your ready made base. Or you could just set something up like the Star Forge from Star Wars Legends, ready to deploy countermeasures, in the system, taking materials from the star. [Answer] # Contact one of the primitive civilizations in their sector. Your civilization resides on Alpha Centauri, a hub of learning and reason. But just a few light years away is Earth, a backward and benighted planet that may never reach a Cardassian level of civilization, let alone any other kind. But as a Centaurian, you're too civilized to squash vermin; you leave the Earthlings to their own devices. The Earthlings have picked up a signal with designs for a small, compact power plant, just 150 tons, which promises *limitless energy* to their planet. Needless to say, the relevant gun-gang keep this data very tightly secret on a single continent, one unfortunately not well monitored by Centaurian agents. All the Earthlings need to do is build it, allow it to burrow deep into the geothermal center of their planet ... and a few years later, most of the planet's mass will spray out as an unstoppable tide of trillions of killer robots ready to wipe Centauri from the face of the cosmos. ]
[Question] [ **This question already has an answer here**: [The Nightfall / Kalgash System](/questions/115068/the-nightfall-kalgash-system) (1 answer) Closed 1 year ago. The community reviewed whether to reopen this question 1 year ago and left it closed: > > Original close reason(s) were not resolved > > > So I'm trying to determine if it's realistic for a planet to experience daylight for most of the year while experiencing nightfall only a few times within that same year? Say, less than 10 times? Also, while still remaining habitable. I'm thinking this would call for a multiple stars situation? What sort of effects/problems would this setup cause the inhabitants? [Answer] ## Eternal day, but mega structure blocks your sunlight.. Suppose your planet has a [tidal lock](https://en.wikipedia.org/wiki/Tidal_locking) so inhabitants on the sunny side would enjoy perpetual daylight. That side always faces the sun. There's only one thing spoiling the party, <https://en.wikipedia.org/wiki/Topopolis> <https://en.wikipedia.org/wiki/McKendree_cylinder> Long time ago, the system your planet resides in was inhabited by a high-tech species. About 900 million years ago, they built a [toroid](https://en.wikipedia.org/wiki/Toroid) mega structure around the sun, to harvest its energy. But in some unfortunate period of their history, their civilization declined, but their toroid solar light collector still hangs there, inside your planet's orbit. It is about 900.000 miles across, about 60x the diameter of your planet. Luckily, this Dyson torus has a very tilted orbit compared to the planet's orbit. Its inclination is ca 30 degrees, so it won't block the sun on your planet permanently. It's not a heavy construct, but it is *big*. Very big. Twice per year, the megastructure will eclipse the sun and there will be nightfall on your planet. (NOTE: if you need more nightfalls, suppose it's a mega structure *ruin*.. some huge parts are still intact.. some day, the planet will collide with these remains, but that is still a few million years away) [Answer] [The Demon Star](https://en.wikipedia.org/wiki/Algol) could be the key to what you seek. If a planet could orbit Algol C, and either Algol A or Algol B were sufficiently brighter than Algol C (and the other sufficiently dim to be less luminous at that distance), you could have true day follow the main star, and alternate day follow the non-eclipsed bright orbital star. Your rare night would occur when the brighter orbiting star is eclipsed by the dimmer star, which could produce moonlight level darkness on the planet. for this to work, the orbits of the binary stars would have to closely align with the orbit of the planet around the primary star, and the co-orbit between the 2 distant stars would have to be relatively slow (a single period would have to be a single day-night cycle, accounting for rotation of the planet as well). This would not allow for nightfall for the whole planet, only nightfall for the side opposite of the primary star, like on Earth. [Answer] **MULTIPLE STARS** The planet is in a system that has 3 or more stars in relatively close proximity. As a result of this, for the period of the year where the planet is in-between its star and the other stars, every inch of the planet is exposed to the suns and their rays. It's only when the planet's sun is inbetween the planet and the other suns that night actually happens. [Answer] # Space Mirrors An advanced enough society might have mirrors in space. They will orbit around the planet in such a way that those who are "behind" the planet in relation to the Sun will reflect light back at it. A sufficiently large amount of mirrors could cause night to look like day. Natural darkness from night could happen when the satellites are out for scheduled maintenance. If you don't want your planet's inhabitants to know why this happens, the satellites could be the work of another species, from a long time ago. The aliens either went extinct or quit the system. Alternatively, a previous civilization of the same species built the system, but war or something else wiped them out. Society rebuilt itself from scratch and now there are at most legends about the space mirror system, if anything at all. The system is self sufficient and can do its own preprogrammed maintenance routines, which is when people experience night. ]
[Question] [ ## The Silver Dominion The great and grand Silver Dominion has a steel clad stranglehold on the continent's metal economy. In possession of WWI era industry and technology themselves, they keep their vast array of subjects in the bronze age, responding to attempts to forge iron or mix gunpowder with extreme prejudice, and the thievery of technology with draconian, scorched-earth measures. The Dominion has little interest in how their subjects govern themselves, with many Kingdoms, Confederations, and City-states under their rule. They simply demand that they each provide food and laborers as taxes per their population. The Dominion's true method of control is popular support. You see, the Dominion is the self appointed protector of the continent, quelling any infestation of monstrous creatures where they may spread. But the real popular support comes from the "Copper Ration". Each citizen gets a certain number of copper coins per year from the Dominion. These go directly into the hands of the citizens, not by proxy via their local governments. ## Question But, in a far away coastal Bronze Age City-State Republic, how will the Dominion representatives ensure that each citizen gets their ration exactly once per year? The the logistics and politics of distribution itself isn't of interest, but how to make sure no one gets double rations. ## More Context from Questions As a specific example, the Dominion might once per year dock a warship in the harbor of a city. On the docks, each citizen must come and get their ration of copper coins. But how can the Dominion distributers ensure that each person hasn't already come through the line? ## The Solution When the Dominion docks their warships outside of the coastal city, setting up dozens of lines on the docks for people to receive their ration, each person first presents their "Nickel", a nickel coin inlaid with copper with their birth name and other identifiers, far too metallurgically difficult to recreate without machinery. This ID (as described in Nosajimiki's answer) helps to pit the people against their local government in favor of the Dominion, and helps with Logistical concerns. They are then marked on the cheek with indelible ink to ensure that they don't come back through. In this way, the Dominion both is able to manage handing out the coins, and also better accomplishes their goal of garnering popular support. [Answer] Indelible ink. This is used [today](https://en.wikipedia.org/wiki/Election_ink) to prevent double voting in some national elections. The basic idea is that everyone who wants their yearly ration presents uncolored hands and after receiving their ration one of their fingers is dipped in an ink that will remain on their skin for long enough for the rest of the rations to be distributed. [Answer] ## WWI Tech is good enough for a National ID system to work It does not matter that the territories are bronze age, what matters is the technology of the capitol. In fact, lower tech territories helps ensure that counterfeiting national IDs is harder than it was historically. Paper Currency dates back to 960AD in Asia, 1661AD in Europe, and 1690AD in America. The basic tenant of making a usable paper currency system is that you must be able to recreate by some mechanical means a pattern that is too precise and complex to be practically recreated. So, pretty much any civilization capable of lithography is also capable of making mass produced paper documents that are hard enough to counterfeit, that societies across the globe trusted them in lue of coins by WWI. The idea is simple: each official birth record is printed in the capitol using the same lithographic pattern. When each member state goes to pay their taxes, it is based on population; so, as people are born, they must send to the capitol requests for birth certificates. Then the person's PPI is handwritten or stamped in the appropriate places and sent back to the local government to be given to the new born subjects. Because it is in the best interests of a local government to distribute as few birth records as possible (so they can pay lower taxes), they will not want to request more birth records than are legitimate, but because the commoners all know that they need their birth records to collect a copper ration, they will be VERY insistent that their local government issue them. So, by in large you are pitting the commoners' interests against those of the local government to make it in everyone's best interest to make sure only 1 record per person is issued. Then, when a person dies, it is the responsibility of the local government to record the death, seize the birth record, and send it back to the capitol. Again, the local government WANTs to record deaths to reduce the tax burden. To prevent minority populations from being excluded, the federal government would send exactly as much copper as it should for the population on file, and if more people to show up to claim copper than are on record, then the local government must BOTH cover the cost of the copper tax and pay for the under declared taxes. If the disparity is big enough, the local government may also harshly disciplined for negligent census handling. You could furthermore have census verifiers go door to door every now and then and sample who can and can not produce identification. If a community has a disproportionate number of people who can not produce ID when asked, then the local government also gets in trouble. So now you have a very hard to counterfeit document that you can make sure that almost everyone has 1 and only 1 of, and comes out of circulation once no longer valid. Then on the back of each birth record, you stamp the year when handing out copper rations so that each certificate can only be used once per year. [![enter image description here](https://i.stack.imgur.com/0cfor.png)](https://i.stack.imgur.com/0cfor.png) ### Why is this a better answer than other answers so far? When it comes to providing absolute proof that each ration is distributed once and only once, it is not. But the more important factor to consider is WHY the copper ration exists to begin with: > > The Dominion's true method of control is popular support... the real popular support comes from the "Copper Ration". Each citizen gets a certain number of copper coins per year from the Dominion. These go directly into the hands of the citizens, not by proxy via their local governments. > > > While the actual payout of the copper tax improves popular support, the federal government is still in competition with the local government for the GREATER popular support, because when rebellions breaks out, people will side with who the like more, not just who they like. This national ID system puts all of the burden and consequences of mistakes on the local government; so, whenever a person can not collect their ration, or has to jump through too many hoops to make it happed, it is not the Dominion's fault for not providing the copper, it is the local government's incompetence for not processing their paperwork properly. So the national IDs themselves become part of the process for undermining the power of local authorities. After all, the DMV will never beat FEMA in a popularity contest. [Answer] **Your skin is your logbook** How and why none of the Dominions regional representatives has their fingers in the cookie jar is for your world building to explain. I understand the question as one of pure logistics: how to make sure everyone gets their share, and *only* their share. The copper is mined, refined, and minted at many locations. They always mint about 10% more than they think they'll be distributing, according to their last census. Every year there is a new design of coin. from each minting location, armies march forth, in their midst huge wheeled strongboxes full of coinage. They halt every evening, make camp, and after dark, anyone may approach unarmed. The distributor counts out the coins, heats them, and with a special tong lays them on the portion of skin that is this years' logbook. The recipient waits until the coins have cooled off and goes on their way. The distributor notes the expense. This can go at a brisk pace, because the distributor can go from recipient to recipient, laying on coins, and need not wait for the cooling. (The process of people approching, with empty current logpage, and then leaving with coins and branding, can be noted by as many people from as many corners of the globe as you like, with as many checks and balances in as byzantine a web as deemed appropriate) Anyone approaching with any years' log-page unfilled can retroactively get their share (in current coinage), if they can take the pain. There is, of course, several alternate log-locations, if you happen to have lost the limb/the piece of skin that represents the current (!) logpage. Children under 6 are precluded, as their skin does not take to brandings reliably. The army breaks camp as soon as the evenings haul goes below 100 recipients. Stragglers will have to follow, or wait a year. Documentation of the excursions informs next years minting, and the path the army will take. [Answer] # Tattoo everyone with a unique mark of iron. Put some iron alloyed with things to minimize rusting in oil filled capsules under each person's skin in a unique tattoo. Then you can check each person according to your records. A simple test with an electromagnet should reveal if the tattoo is truly iron under their skin, and any fakery can lead to an execution. Of course, accidents may destroy some. You should open by tattooing any children who have come of age and anyone who has lost a limb or missed a previous levy. ]
[Question] [ Most sci-fi today is imho unimaginative and unrealistic when it comes to future orbital and interplanetary vessel design. What will spaceships and habitats look like when we build them in zero-g using vacuum deposition techniques and materials mined from asteroids? Gone are the familiar cylinders, wings, aerodynamics which are all legacy to an atmosphere. Gone too are spindly thin constructions, since construction material mass will be plentiful (when mined from asteroids). I don't think vehicles will be long with engines on the end. This means the crew would be constantly climbing ladders and using elevators when under thrust. This leaves squat, fat blobs. Who has explored this area the most, where can I find the best collection of well thought out plausible designs? [Answer] This is a bit of a frame-shift answer. I am answering as a space enthusiast, but also as a person at an aerospace company. Let's not dismiss the simple shapes, such as cylinders, as hangovers from aerodynamics too quickly! There are some important considerations, even with plentiful material and practically no gravity, which may lead to simple shapes (cylinders, spheres, rectangular prisms) dominating spacecraft development. # Center Of Mass and Center Of Thrust There are still virtues in aligning center-of-thrust and center-of-mass, like not spinning out of control! For those unfamiliar with these terms, the center of mass is the 'middle point' of all your mass, and center-of-thrust is where your 'push' from your engines points to. Not lining these up results in your spacecraft spinning, so something needs to be done to counteract this. A design which avoids spending more fuel to counter any moment/torque produced by oddly-placed engines on oddly-placed shapes will be preferred over others. It turns out if you build a known shape, (such as a sphere, a cylinder, a brick) you have a decent idea of where the center of mass and center of thrust could be. This even accounts for odd loading! If you build an irregular shape, you need to do a lot more math to account for mass distribution and thrust. Depending on loading, even rockets with gimbals (ones whose nozzles can point) may not cut it on these eccentric shapes. This issue gets compounded if the engines used cannot be throttled or more than one engine needs to fire for 'forward' motion. Odd shapes could easily rely on multiple engines for simple 'forward' motion to account for loading or structure. This introduces more failure points, which is a less robust design, which mean it will be less favored by practical design. Further, if the engines' output must always be full blast or nothing (no throttle), good luck getting 'backup' engines in the correct place. Simple shapes usually mean you need less engines for 'forward' motion and rely on modest gimbaling to account for a lost engine or irregular loading. # You Still Need to Build It Hey, there may be a galaxies' worth of material out there, but you still need to put in the time and effort to build the ship. That still costs something; time, possibly money, and certainly resources. It turns out simple shapes allow you to minimize the amount of material while still getting the volume you want. Okay, maybe ships will not always a brick or spheroid, but these shapes *do* have nice volume-to-surface area ratio compared to others! # Mechanical Stability Considerations It is cool that your spaceship looks like an anemone, but it bends like one, too. That is not fun when your mess hall is on one tentacle, sleeping quarters on another, and your pilot is on another. Poor Bill had to wait until the acceleration maneuver was finished (which was a full year!) before the hall to his quarters bent back into shape. That is better than Steve- his tentacle just snapped off during the last emergency correction. Maybe if the ship was a simple shape to bear the loads of thrusting and maneuvering, issues like this would never happen. Something like a spheroid or rectangular prism... These shapes are capable of supporting themselves with less material and clear load paths when compared to something more spindly. A more robust shape may allow for more aggressive maneuvers for less material (or 'primary structure'). Less primary structure means more room for payload or yet higher acceleration maneuvers. Overall, these things are desirable for most spacecraft. # Thermal Considerations You need to be careful about your thermal control surfaces. If a radiator (to get rid of excess heat, one of the only ways in space to do so) is next to your thermal camera, all you will see is your radiator. How do you avoid this? You choose a shape which have surfaces pointing away from each other. Spheroids, cylinders, and cubes do not have this issue. The other solution is to have 'cleverly placed' sensors, which does open up some possibilities for odd shapes. (See ISS- not all of those panels are solar panels!) [Answer] One reason (well a couple of related reasons actually) why ships designed to operate beyond Mars WILL be long and spindly is they will probably have a nuclear powered engines. In that case you will want the Red Hot Glowing Nuclear Death as far from the crew compartment as possible. This is because you don't want to shield the whole reactor (shielding is heavy and every gram counts) so you will use a Shadow Shield just big enough to ensure the crew compartment is in the shadow. The further away the reactor and shield are, the smaller the shield can be, but equally you want the structure to be as light as possible too, or it will end up weighing more than the shield would. Therefore you end up with the engine (or at least its power supply) on the end of the longest, lightest possible boom that is strong enough to do the job, and a long spindly ship... Habitats of course are not as restricted on their mass budget and may well have more freedom of form, although as pointed out by PipperChip in their excellent and comprehensive answer, spheres, cylinders and the like are well understood engineering forms with good surface to volume ratios and other desirable characteristics, so are likely to be preferred for those reasons. Plus, if the habitat is large enough, a cylinder can most easily be spun to produce artificial gravity. As for "...the crew would be constantly climbing ladders..." Near future space craft are likely to use very efficient engines that consume little propellant, but also have very low thrust. Accelerations are likely to be well below one tenth of a G, so crew should be able to pull themselves along quite easily. ]
[Question] [ The Sarkic empire was the superpower of the ancient world, spanning the globe across multiple continents and subjecting their people to their benevolent rule. Although they were an authoritarian nation that is involved in the slave trade, they also embraced the free market principles of capitalism and private enterprise. Their influence extends from technological advances combined with magic to create arcano-tech. This technology is infused with mana, a form of energy used to perform rituals. This combination gives technology their magical properties and attributes, increasing its power and dexterity. This forms the base of their power and has made them the most dominant empire in the world. The creation of magical texts is a different matter. The Sarkics use a process called Anthropodermic bibliopegy, the practice of binding books with human skin. This rather macabre practice is used to make parchment to store rituals and instructions for spells, such as the Necronomicon. When a book or scroll is needed, a slave, often a prisoner of war, is killed and their remains are used as material to create the parchment. These are then sold to mages for their personal and private use. The most important aspect of a free market system is maximizing efficiency. Increasing output while reducing costs is the goal of any corporation, as it helps them to remain competitive with other businesses. The advent of arcano-tech has led to many advances in knowledge, new kinds of products, such as E-books. Information can be downloaded or uploaded with a click, increasing access to information. The amount of money and power that stems from this to the wealthy is usually enough to override foolish traditions and excuses such as " We have always done it this way ". However, the process of bibliopegy is very inefficient, as it wastes valuable resources and is time consuming. Maintaining a slave population is also expensive, especially when the benefits of arcano-tech is on display to all, and would make a suitable replacement as opposed to this ancient practice. What would make this form of storing texts more preferable to more efficient methods? [Answer] Human mana permeates the parched skin and ensures that the spells written in the books do not consume themselves. The human skin in this acts like a sort of sacrificial anode, which gets slowly consumed instead of the object it is meant to protect. Books which use synthetic materials simply fade away over time, while animal skins tend to alter the writing, damaging the content. [Answer] ## Human souls can handle a lot of the AI and mana issues. It's very easy to bind a human's own soul into the parchment. This supplies mana and leads to longer battery life, superior AI, and a much thinner finish than other solutions. It just makes sense to use human skin. It's also cruelty free, unlike more modern solutions which involve abusing often hard working Sarkics to work in poisonous and dangerous factories to produce the components for modern technology. No Sarkics are harmed in the making of it. [Answer] **Containment plus.** Mana flows freely in the natural world but only in very small concentrations, like a single drop of perfume in a lake of water. The books contain a greater concentration, and this wants to leak out, to flow freely in the world, like any concentration of vapour, it will spread if given a chance. Given the freedom to do so, it will leak, become weaker in the book, leaving unwanted traces in nearby objects, tainting them - other books, bookshelves, desks, sleeping cats - and can generate "unwanted side-effects", no need to go into details here. The only effective barrier found to this is the skin of humans which are naturally endowed with a sort of opacity to magic in one direction (it's important in the binding process to ensure that the skin is on the right way round, or it defeats the purpose). The additional advantage to this is that the faint concentration of mana from a book's surroundings can pass through the skin - into the book. This might make a book stored in a particular place, at a specific time of renown have the added value of provenance. Over time, like a fine wine ageing, the book's potency can increase. None of the tech-substitutes can make this claim. [Answer] #### Smell The mages have a such sophisticated sense of smell that they can recognise a person or their pet wolf. But with other animals it's not enough. They can't tell a cow or a sheep from one another. To protect the books they put no title on the cover, the mages carefully choose the right skins to for the parchments and eventually each book has a very distinctive smell, at least for the mages, and the smell will be used every time the need to pick a book from the library. [Answer] # Gravitas A mage study inspires much more respect and awe if it is filled with books bound with chains and human skin than if all it has is an Amazon Kindle on a table. [Answer] Binding books in human skin is a real thing, verified by DNA tests: <https://en.wikipedia.org/wiki/Anthropodermic_bibliopegy> If we're counting magical justification, it could be the skin of enemies as a warning to not mess with the owner of the dæmonic texts because you don't mess with people who kill their enemies and wear their skin. Similar to this magical principle: "These nine lamps were originally candles made of human fat, the fat of enemies slain by the Magician; they thus served as warnings to any hostile force of what might be expected if it caused trouble." [Answer] **Magical texts are instructions and contracts read by daemons.** Contract with daemon written on medium from human skin makes daemon respect you, and prevent them from altering it If you offer them something on cheap paper made from plants or parchment from animal, powerful daemons will consider you to be an amateur, and sometimes will simply refuse to read instructions and obey them. Junior daemons will probably obey instructions written on non noble mediums, but employing them can be not worthy. If senior grade daemon can easily power and control magical factory or gigantic golem, basic grade daemon can maximum power small steam engine, control alarm clock or act as small janitor automaton. Also its worth notice, that plants, animals, stones - are made by oldest and most powerfull daemon which name we are not allowed to speak. This daemon can simply alter things he created, so magical texts on non honourable medium can be simply altered by daemons, to help them not perform their job, but to enslave humans who tried to control them. Senior grade daemons has some degree of power of oldest daemon, so they can alter instructions and orders on non honourable medium, only weakest daemons cannot do it. But humans, including their parts like bones, blood and flesh are made by Great-Builder-The-Creator-Of-All-Things, so human skin is considered as honourable medium, and it cannot be altered by any of daemons. Sometimes, using human blood as ink can be used for magical contracts, but it is not so durable. Sooner or later, daemon will try to abuse this contract. That's why only human skin can be used as medium for writing magical contracts with powerfull daemons. [Answer] The very fact that something valuable was used to create the book makes it work better. Sacrifices of valuables are important, and therefore the magic they make is important. (Law of Similarity.) Very valuable texts therefore use slaves in the prime of life, or otherwise distinguished such as being very learned. Especially valuable ones pick of slaves of great value, such a slave in the prime of life, extremely strong and good looking and intelligent. Run of the mill ones use sickly children who won't grow up and elderly slaves who have been used up. Besides, the daemons like the murder. It predisposes them to like [Answer] The source of the mana explains the need for human remains in the ritualistic literature. It should also be noted that very powerful spells require not only human remains, but specific and anatomically scarce remains of very important humans to work properly. Even lowly spells can be enhanced by combining the remains of multiple victims and harvesting those remains in painful ways from their still living owners. The source of mana is demonic. The devils and demons who provide it within the human world have an unfathomable hatred of humans, God's favorite pets. They were banished from paradise and forced to live in a lake of fire, while those pathetic humans got to live on a planet which (long ago) was almost as nice as heaven. It is rare that the demonic forces will deal with humans directly. Most of the power they pour into our world is used to manifest earthquakes and hurricanes, to slowly poison our world almost as effectively as we have learned to poison it ourselves. But on occasion, a creative (and morally bankrupt) human mage comes up with a way to entice demonic assistance. The human skin books are one of the best ways that have been found so far. It is rumored that an atrocious, tremendously powerful tomb exists which was made from the facial skin of dozens of kings, saints and willing martyrs. No one is quite sure what magic it is capable of performing, but few alive would be willing to open it should it ever be found. Some demonic blessings are just too much for mere mortals. [Answer] **Ritual surrender** A kingdom gets invaded by invincible deamons, therefore they win. The document containing the deamonic conditions of surrender will be written on papyrus cured from the skin of the defender's heir to the throne, and written with his blood. His father the king is forced to sign the document. ]
[Question] [ What would tank design or even replacements look like in the far future. The proposed tech level is something akin to the expanse, but for hand wavy reasons ships in orbit cannot just bombard enemy positions from orbit or drop fighters/jets into orbit behind enemy lines. Thus a ground war of sorts will exists w/ two sides vying for control over a planet or a moon or a rock etc. What would the next evolution of tanks or even there replacements look like in a situation like this. Taking this a step further and assuming that there are multiple planets in a solar system like earth that can sustain human life perfectly (some contain lots of jungles, others are more uniform in environment types, others are more flat like deserts/plains etc, but all are more than capable of sustaining human without much terraforming needed). How would a faction develop a replacement for tanks that could work on multiple terrain and celestial bodies. At present current tank design doctrine is based around earth and the assumption that tanks will be deployed in areas where they are best suited/against countries where they are best suited (cold war tank design for example played into this). Ideally the replacement should be a basic pattern that is modular, such that the use of specific vehicles for every different type of environment becomes unfeasible. Edit: I should have been more clear about this, but by something on the tech level of the expanse, I mean that humanity has the capability to traverse the solar system and colonize it. The technology of the expanse can be best described as near future, as there are no FTL/warp drives. Almost everything is mechanical in nature, space travel exists, but its still very dangerous and an absolute pain. Things still require fuel, there is no anti gravity, the only way to get 1g in your ship is to move at 1g, else you will be weightless or pulling hard Gs. Sending and receiving messages takes a time delay, there are no mega laser cannons like in star wars or stargate. Rather the weapons are still very much kinetic based with the likes of rail guns and torpedo's. Though in my setting early weaponized laser systems are being developed for anti ship combat but they are filling in a niche roll that's not been completely developed yet. The existence of multiple planets w/ earth like conditions generates a lot of interest in space travel early on so there wasnt a need to develop heavily armed and armoured space warships because the first concern was getting large ships to carry humans out there in the first place, and have smaller ships with maybe a single gun on it for patrol against piracy or hijacks. This means that the ships are rather weak in there armor, its not like they can tank a lot of damage: mines, small space based rail gun platforms, boxes of just torpedo's/ sentries free floating in space, or even ground to space/orbit weaponry like heavy railguns or missiles would do significant damage to a ship trying to sustain orbit around a planet or attempt to bombard from space. Essentially ships are like glass cannons at the start of the conflict. As for drones and planes, they would still be able to fly, its just that they can be affected by existing countermeasures or just plain shot down, deploying them from an air base is just safer. Its just that for a ship to carry a bunch of drones or planes to position above an enemy in orbit then deploy those drones is very risky as it has a high risk of being shot down (this problem extends to transports and replacements for both parts and soldiers which is a major part of the story). Essentially once a planet has a pretty good ground to space defense setup, approaching it for both sides is a suicide run for a good part of the war. [Answer] I'd say the tank is going to stay. What a tank is? A mobile, protected platform for heavy weapons. Tank track seems to be the most efficient way to provide vehicle with all terrain mobility. The ground pressure of the tracked vehicle is simply incomparable to any other chassis. And track is relatively easy to repair and maintain in difficult conditions. So unless you can cheaply produce anti-grav devices, tracked vehicles will be used in difficult terrain for the years to come. Protection, as @PcMan mentioned is more and more difficult. But tanks never were made to be completely impervious to any weapons. They were made to protect from the most abundant weapons enemy has. Unless common rifle can pen any armour, armoured vehicles will still be part of the military. And there will be always need for heavy weapons on the battlefield. So if those above are to stay, what will change? 1. Crew reduction. Absolute minimum for efficient tank crew is 3 - driver, gunner and commander. Loader is still more efficient than loading mechanism, but SciFi tech could take care of that. You can't really cut the crew below 3 without compromising something important (either you can't shoot on the move or properly judge situation and command other tanks). 2. Crew could be replaced by remote pilots... Unless enemy has tech to block connection or, worse, hack into system. Then you would suddenly regret it. 3. Most probable IMHO would be either AI controlled tanks or tanks with commander only, with rest of the functions performed by AI. Commander would be there to give orders and just in case you need someone to press a mechanical switch off button. 4. You can't remove too much armour as you want engine, ammo and crew/computer protected. That stuff is too expensive to be made completely expendable. This protection will be dropped only if: * common trooper can pen it with basic weapon. * terrain is so difficult that even tracks cant support properly armoured vehicle. Even today lightly armoured tanks are used in countries with a lot of jungles and other bad terrain. [Answer] There won't be one single solution. On a world with lots of rivers and sea's you are better off with boats, ships and amphibious vehicles. On a large flat planet tracked and wheeled vehicles would be key. On a planet with mostly hills and mountains you would use multi-legged vehicles. If you still want a generalistic answer then multi-legged vehicles will likely be the most superior for land use. There is little use in bringing a wheeled/tracked vehicle to a planet where you can't use them for most of it's land surface area, but a multi-legged vehicle would still be useful in those environments and have far more mobility in hills and mountains where even tracked vehicles can only reasonably pass if roads have been constructed. Archelaos's answer mentions that tanks have the lowest ground pressure but misses that this is a requirement for tanks to exist and that legged vehicles can surpass them if you engineer the feet like a real-life designer rather than a game developer. To turn most of the tank tracks slide across the ground, if the pressure is too high the tank will both rip the ground/road to pieces and it's turning rates will be debilitated, hence why tanks are required to have such specifically low ground pressure rates and few tanks will have smaller tracks. This makes sense, tank tracks are some of the most vulnerable parts of the tank and would best be as small as possible, the only reason to keep them this large is because it's necessary. The feet of legged walkers can be engineered to have a large surface area as well. For simplicity imagine a non-turning track at the end of the foot, turned sideways and pointing to the center of the vehicle. The suspension adapts the foot to any uneven ground it tries to rest on, the fact that the track is pointed inwards means the vehicle template wont be ridiculously large and the feet don't get in each other's way and it means that a 6-legged mech could have more track to stand on than a regular tank reducing it's surface area even more. Naturally having current tracks for feet would be inefficient. It is just to illustrate the point that feet design as shown in games and movies is done by people who have no experience designing support surfaces. They would never have designed a leg prostetic like this: <https://www.google.com/search?q=leg+prostetic+carbon&oq=leg+prostetic+carbon&aqs=chrome..69i57j0i8i13i30j0i8i13i30i457j0i8i13i30l2.11427j0j7&client=ms-android-samsung&sourceid=chrome-mobile&ie=UTF-8#imgrc=KZF842-EttKNJM> Feet design would include things like spikes along the bottom to better get traction when climbing steep terrain or ram them into mountainous area's to get into places a tracked vehicle can't even dream off. It could also use suction and earth compaction with each step to increase it's chances of passing over the terrain. Multi-legged vehicles do not have to be the slow, lumbering vehicles portrayed in movies and games either. Having multiple legs also means redundancies. A tank with a blown track is disabled, an 8-legged Mech of 50 tons could still be moving if it lost 3 or 4 of it's legs, although it's speed would be decreased. A common idea is "just shoot the legs". That is a court-martial offense if mechs were real. Unlike wheels and tracks a leg can be completely armored, legs are also the parts that move and shift the most. Anyone with a weapon capable of damaging a tank would fire for the hip-joints. Those joints are the largest, attached close to each other so a miss could mean you hit another one instead and even if you miss all joints there is a good chance of damaging other components on the main body. This means that a mech would be inbetween wheeled and tracked vehicles in terms of vulnerability of their locomotion. A wheeled vehicle can lose more wheels and doesn't damage the vehicle if all wheels are destroyed, a tracked vehicle is disabled faster but it doesn't damage the vehicle to lose the tracks, and a legged vehicle does suffer from crashing to the ground if too many legs are destroyed (assuming you haven't lowered the chassis by then to reduce a potential catastrophic loss) and the legs are the most armored and resiliant compared to the other two. Legged vehicles would have the most jack-of-all-trades capabilities and would be the best if you had to stick to one and one alone. However anyone smart would bring everything they've got, boats, ships, wheeled, tracked, legged and even hover tech. [Answer] **The one tank is very popular with the top brass. It is often horrifically unsuited to its current applications.** Consider the Sherman tank in ww2. <https://archives.library.illinois.edu/blog/poor-defense-sherman-tanks-ww2/> > > The M4 Sherman was the primary tank utilized by the United States army > during World War Two. It also became the main tank of the other Allied > countries, except for Russia. The popularity of the Sherman was not > due to its superior design, but its availability and mass production. > On the contrary, this tank suffered from serious design flaws. Perhaps > it is more appropriate to say that it was the soldiers within these > tanks that bore the brunt of the Sherman’s problems. > > > In your world, the tanks used in every military endeavor on every planet are essentially the same tank designed for a war 40 years prior. There are a lot of these tanks and a lot of resources committed to making them. They are hometown favorites and imbued with patriotic fervor. The persons in charge of purchasing and the military-industrial complex are committed to making this tank. It is the best tank and that is that. And it was a fine tank in its time. It was good for its original uses. Every now and then the current generation can see why the machine was so popular. But now this tank is mostly a source of great frustration to its end users. End users have standard hacks and modifications that they put on new tanks when they show up, trying to fit the square peg of this tank into the round holes that are the various planets where they are deployed. Hacks and mod are idiosyncratic and one can often identify a tank brigade by the mods on their tanks. Tank crews battle their own tanks as much as the enemy. --- For one, this is historically a thing that happened. But more importantly, conflict makes for an interesting story. An optimal tank does not offer much conflict. If your characters are wrestling with their archaic machine at the same time they are battling the enemy, that will make things more interesting. [Answer] ## Modular Machines: No one machine will ever do all the things on the battlefield that are needed to be done. A tank fights big things better than anything else. A military truck will haul equipment better than a tank or anything else. An APC will always be needed in any environment where humans are present and significant to the battlefield. So to say anyone can have one vehicle that can go everywhere is silly. You hit it on the head to say the design needs to be modular. I'll take that a step further, and say your battlefield will be populated by EMP-shielded mostly autonomous AIs mounted to a chassis. The engines, armor, and weapons will be mated up to the chassis to fulfill whatever role is needed (or based on what's available for parts, but that's every war). The AI and base chassis should be small enough to mount within an armored frame that can fit down an average human hallway or through a human door. The same chassis can mount to a truck, firetruck, VTOL/STOL vehicle, etc. If you want to give the AI a human-like personality, go ahead. It isn't needed, but this is the only way "humans" would be relevant. Most of any of these vehicles that do fighting will be a simple conveyance with a gun large enough to destroy targets on the field. The specifics of the weapon will be constantly changing depending on what you need to fight and the capabilities of the weapons available. The conveyance will be unique to the environment (either selected or modified on-sight to match local needs). So it could be anything from a small VTOL drone with a rocket launcher to a "small" armored fusion reactor on treads spewing plasma. Armor will still be relevant, but heavy armor won't be. If you fail to armor your vehicle at all, then the smallest, weakest weapon on the field can defeat it. But the nature of the armor will be highly variable and likely directed largely towards protection from light, routine threats and the environment. The point is, the vehicles will never look the same, but they will have the same independent operating system (AI + chassis) will run every component on the field that needs to be involved in the fight. * PS. Upvoting PcMan's answer; it's similar, but different enough to be a separate answer (and everything I said would be too much for comments, anyway). [Answer] **troop transport**, less armor more cargo, The terrain advantage of tread but built for capacity or speed, that is tanks geared to troop transport. The big advantage of tread is the ability to transverse a wide range of terrain with ease because of the huge contact surface. The future will be more and more about how fast you can get assets on site, and you can't send troops by UAV, tread handle a much wider range of terrain than wheels but are much faster and support more weight than legs. You can see slower more conventional set ups of high speed lightweight ones like the ripsaw. The basic concept of an armored box to put troops, or anything important in during transport looks even more enticing in the age of drones and robots. **Mobile heavy weapon platforms**. We see this use often now tanks with little armor but uses the advantages of a heavy tread platform to move heavy weapons in to position. look at the M270 or M982A1 in use now. basically you will see tanks that act as mobile platforms for missiles, rockets, armillary, drones launch, or other unusual weapons that are too heavy or large to be fit on smaller lighter platforms. **Mobile sensor arrays**. We see tanks being used more and more for this, tanks as a mobile platform resistant to opportunity attacks make great places to set up monitoring and communications equipment, whether manned or drone. We already see small drone tanks being used for this, the ripsaw is a drone scout tank. **Main Battle Tanks**. in conflicts between major powers you will still see main battle tanks in use, this of course depends on the political situation of your future. MBT are very expensive, but also very effective in war focused on holding ground. **Armored construction vehicles.** lets face it construction vehicles in combat situations are both often necessary and enticing targets. the only effective way to armor them is to use treads. conventional construction machines are fine away from combat but anywhere near actually fighting they are rolling bullseyes, which is why we use armored construction vehicles today. [Answer] Think: Spot the Dog on steroids.[![enter image description here](https://i.stack.imgur.com/SCnim.jpg)](https://i.stack.imgur.com/SCnim.jpg) Given that the power supplies of the future will be able to deliver huge power/weight rations, scale Spot up to a size where a human would fit into the belly. Now, add tank treads to its belly. But not just any tank treads, [wheels that can convert to tank treads](https://www.popularmechanics.com/military/a21932118/darpa-wheels-become-tank-tracks/). So when spot lies down, he can move using the wheels, but when the going gets tough, the wheels become treads. When there is a wall or such, Spot rises up o his legs and climbs over. Oh, did I mention the jets in the legs, so for very limited distances he can 'fly' like those jet-kite guys in Dubai? That really neat arm that opens doors would serve double-duty as a rail gun/rocket launcher. As a final touch, make Spot amphibious, so he can swim across rivers and such. [![enter image description here](https://i.stack.imgur.com/MDflr.png)](https://i.stack.imgur.com/MDflr.png) ]
[Question] [ The setting is as follows: a 3-Dimensional-Space(3-DS) character/Spaceship has entered the 4-DS and has encountered a planet (from far away). Now he wants to orbit around it, but the planet is a 4-DS planet, so either our character can't see 1 dimension or he can see it all well, but he can't make any sense of what he's seeing. Imagine you are a 2-DS character and know how a circle looks like (from the side) but suddenly you enter 3-DS and you encounter things like a sphere, a cylinder, a cone or a donut/toroid and he can't make any sense of them. And that's only taking into account regular spheres. Imagine encountering a radiator or a pile of rubble. For that he would need a flight computer to tell him an approximation of what he's seeing. The same for our 3-DS character. Now for the problem at hand. Could the 3-DS pilot orbit and maneuver around a 4-DS planet with his spaceship? [Answer] Your character won't be able to orbit around the planet, not because of their inaptitude, but because of [physics](https://en.wikipedia.org/wiki/Spacetime#Privileged_character_of_3+1_spacetime) > > In 1920, Paul Ehrenfest showed that if there is only one time dimension and greater than three spatial dimensions, the orbit of a planet about its Sun cannot remain stable. Ehrenfest also showed that if there are an even number of spatial dimensions, then the different parts of a wave impulse will travel at different speeds. > > > [![enter image description here](https://i.stack.imgur.com/nAVTG.png)](https://i.stack.imgur.com/nAVTG.png) There will be no planet to orbit around, no star for the planet to orbit around and so on. [Answer] ## Geometry [![enter image description here](https://i.stack.imgur.com/K8LzF.jpg)](https://i.stack.imgur.com/K8LzF.jpg) Yes, your pilot can navigate. Four dimensions of space can be projected onto a 2D surface, just as we see three spatial dimensions projected onto our 2-dimensional. You can simulate this, even in current graphics engines by expanding [quaternions](https://en.wikipedia.org/wiki/Quaternion) into quintonians for all of your basic geometry. Quintonians are quaternions with one more rotational term added to them. Some folks are already looking at [adding them to modern graphics engines](https://github.com/sholtodouglas/learning_from_play/issues/3). If your curious, the above graph shows you the familiar coordinate axes, with a fourth spatial dimension added as "w", "x", "y", and "z". As you can see, it's typically impossible to see all four dimensions at the same time, because they just crowd one another out. As to smooth transitions to and from 3D to 4D space, I imagine compactified dimensions exist, and one of those compactified spatial dimensions "opens up" as you get closer to the body. If your pilot knows that the 4D space is out there, then, it is possible for the pilot to use an appriately equipped simulator to train and build up experience flying in 4D. Another problem your pilot will have is that the controls for your spacecraft probably only provide control in the 3 familiar dimensions. It's possible to navigate safely in 4D by using a combination of 3D maneuvers to get to the same 4D attitude. That's the kind of thing that will require foresight, planning, and practice. ## Physics Let's reconsider this just for 4D : The [drop-off rate for forces](https://physics.stackexchange.com/questions/176811/inverse-square-law-and-extra-space-dimensions) is $F = {1 \over {r^{N-1}}}$, where r is distance and N is number of dimensions. For a 4D universe then, the force of gravity is re-formulated as $F = {GMm \over r^3}$, where you can drop off the mass of the orbiting item m as trivially small and get the easier $F = {GM \over r^3}$ An orbit is where centripetal forces ${mv^2 \over r}$ match the force of gravity ${GM \over r^3}$, so that you neither fall or rise. Dropping m again, $v^2 = {GM \over r^2} \rightarrow v = \sqrt{GM \over r^2}$ Escape velocity is computed differently, using potential and kinetic energy. Orbital potential energy is the integral of force $W = {{GM} \over {3r^2}}$. Kinetic energy ${1 \over 2}mv^2$ at escape is greater than or equal to potential energy ${{GM} \over {3r^2}}$. * ${1 \over 2} mv^2 = {{GM} \over {3r^2}}$ * $v^2 = {{2GM} \over {3r^2}}$ * $v = \sqrt{{2GM} \over {3r^2}}$ Tying the two together, escape velocity $v\_e = \sqrt{{GM} \over {{2\over3}r^2}}$ Yet the orbital velocity is $\sqrt{GM \over r^2}$ Because of the $r^2$ term, the force of gravity is dissipating at a tremendous rate in the 4D world. Escape velocities are tiny. For an Earth-sized mass, escape velocity is ~3 meters per second. A Jupiter-mass planet in an Eart-sized frame would have an escape velocity of only ~80 meters per second. These two numbers (stable orbit and escape velocity) are also very close to one another, and as "r" increases drive closer and closer to being the same number. I think, then, that it doesn't really matter what the "orbit" is. You are probably following the trajectory of the 4D planet wherever it goes. It's gravitational effect on your ship is trivial. [Answer] **Strange, but visible** Your 2D example is actually perfect. Imagine this 2D character is seeing a pillar, a ball and a pencil. The moment the character starts moving through the 3D space, it'll still perceive 2D. That means some things will seem the same, or slightly different, while at other times they disappear or other things appear. The same is likely true for 3D to 4D space. There is a game in development that makes use of this concept, called Miegakure. It's quite interesting to see the landscape change based on this 4th dimension you move in. The thing is, you can extrapolate this to a bigger scale. Imagine a 2D character in a spaceship that suddenly gets into 3D space. The spaceship will orbit if it'll have the right speed and direction. The human will probably not be able to understand, or understand enough and navigate this space. A computer however doesn't have these problem. It works with the parameters given. That is why computers can calculate with many more dimensions, as long as the parameters are given/calculated. There are many assumptions here, like that it is actually possible to move in the new dimension. It might be that the ship can't navigate in the new dimension, being locked to the forces of nature. Like an airplane finding itself suddenly in space. However, it might be able to by chance or preparation, like a 2D thing suddenly in 3D space having surface area to move into wind and alter it's path. The thing is, we don't know or understand how your 4D space works. That means no one can make a true prediction, except that in theory it isn't possible, as in L.Dutch his answer. ]
[Question] [ Human souls are immortal, and possess the potential to become one of two things after they die. Their souls can rise to the celestial realm as part of the celestial host, becoming infused with the realm's energies and transforming into an angel. Alternatively, their souls can descend to either the Abyss, a realm of demons, or the 9 Hells, the realm of devils, where they will be fought over by both sides. Over thousands of years, the souls will be brutally tortured for their energy to serve as fuel for the denizens of the Abyss or the 9 hells until the soul fades into oblivion. Demons have the ability to possess human mortals, transforming them into demonic hosts and giving them the powers of that demon, as well as enhancing physical attributes such as strength and speed. Through a summoning ritual, they are able to forcefully take control of a human and cause havoc on the plane, using the host as a puppet. The devils also wish to use this ability to take control of human hosts in order to walk the earth, but there are significant barriers to this plan. Devils are former angels who rebelled against God in the war of heaven. These rebels, led by Asmodeus, were cast out of the celestial realm into hell, where they organized their own hierarchy and made war with the denizens of the abyss. As angelic spirits are basically souls super charged with celestial energy, they should be directly compatible with human souls. This should make humans a perfect glove for the angel, allowing them to a perfect subject for possession. However, this is not the case. The devils are forced to take alternative methods to complete their plans. This is done through the creation of cults devoted to worship of these devils. These cults would undergo a breeding program over the course of hundreds of thousands of years to breed an artificial soul, known as a homunculus. This soul would be able to be possessed by Asmodeus, and allow him to walk the earth and conquer it. The human soul was specifically designed to absorb celestial energy, as they were meant to become angels. As such, they should serve as perfect hosts . It is not a question of free will, as Asmodeus and his legion were capable of rebelling, proving that angels were not slaves to God's machinations. Nor is it a question of power, as there are demons who are as powerful as devils, with some even surpassing them. What would prevent human hosts from being perfect vessels for angelic spirits? A good answer would center around how an artificial soul would be a better fit for possession than a naturally created one. [Answer] ## Because Devils are too low on the Great Chain of Being Since you seem to be looking heavily at Medieval Christian Demonology for inspiration, I would suggest adding another element of that culture which is the concept of all things seeking to sink or float based on how similar to God they are. Before the concepts of density, buoyancy, and gravity were fully understood, the Church explained that holy things like fire and light would seek to ascend in the direction of God where they would form the astral bodies, and less holy things like rocks would be repulsed God's presence and descend to sink to the lowest depths of the natural world. And this was their explanation for why the world seemed to seek the ordering of Earth > Water > Air > Fire. This was the basic principle behind the Great Chain of Being. But this was not just limited to the 4 elements, this was believed to be a universal law that applied to the spiritual universe as much as the physical one and was used to categorize all manner of things as being better or worse than others in the eyes of God. They believed that higher orders of beings would ascend over other beings to be closer to God, and lower levels of beings would sink further away from him to experience greater torment farther from his presence. Dante's Divine Comedy is a really good example of this concept that most of us are probably familiar with. When you look at his 9 circles of Hell, the very bottom tier of existence is reserved for betrayers, and at the very bottom of the this last circle are those who betrayed God himself. To betray God would make your soul heavier than any other material or nonmaterial in existence. The Medieval Church also believed that the better you understand the difference between good and evil, the more evil it is to commit a sin. So, to be a Devil means you had a perfect understanding of good and evil (thanks to having been an Angel) and you chose to do the most evil act there is. This makes Devils the most spiritually heavy things in the universe. The reason Demons possess humans is because they use us as life rafts to keep them from sinking back into their proper layer of existence, but the vast majority of damned souls are sinners from the upper 8 circles of Hell, or what you would call the abyss, so the higher up a demon comes from, the easier it is to use a human host to "float". But those devils who are from the bottom layer of damnation are just so heavy that they would drag a human soul down into hell instead of being held up by it. The reason they need to breed a special human host is because they can only possess a human soul that is so good and like God that its pull toward heaven is strong enough to keep it from being dragged down to Hell. But human souls can not actually get that holy, or they would ascend into Heaven like Enoch, Elijah, or Jesus did. That is where the "homunculus" comes in. The homunculus is a human's state of being just before they reach the state of living ascension, but the problem with these saints is that no one normally gets to this point without also obtaining enough spiritual power to make short work of any devil that tries to possess them. This makes the homunculus a very special sort of saint, one who is good enough to ascend, but weak or passive enough to not fight back. Extraordinary pacifists like Gandhi and Martin Luther King Jr. would have been great candidates for the role of homunculus, but both were assassinated before they quite reached the point of living ascension; so, you could as a plot twist ascribe these sorts of assassinations to the efforts of rival demons or even angelic beings trying to prevent homunculi from reaching maturity. [Answer] So we're after the difference between a demon (created by the torture of a soul in the Abyss) and a devil (tortured instead in the Nine Hells). Seems simple enough. Something in the Abyss alters a soul in a way that makes it possible to possess a human -- something that doesn't happen in the Nine Hells. This isn't so much a property of the souls of demons and devils, as such, but more an inheritable property of the Abyss. As Neitzsche is often quoted to have said: "...for when you gaze long into the Abyss, the Abyss gazes also into you." This process, the mutual gazing that can only occur in the Abyss, creates a sort of "porosity" of the soul that lets it enter a human in a way one not so altered cannot. [Answer] Both angelic and demonic souls are aetherically "larger" than a human soul - they simply won't *fit*. The human mind and body would collapse if an angelic soul were forced to fit. In the Abyss, souls get aetherically "shrunk", to the point that they fit. Devils and angels both know this, but won't follow that road - the process is immensely painful, and nobody would undergo the metaphysic equivalent of a frontal lobotomy plus multiple amputation no matter what the reward. The infernal breeding program therefore aims to create a "superman" with, so to speak, a larger "soul socket" (Descartes believed this to coincide with the [pineal gland](https://plato.stanford.edu/entries/pineal-gland/#DescViewPineGlan)). This would also allow the same individual to be possessed by an *angel*, though. [Answer] **Demons Possess Humans. Humans Possess Angels/Devils.** When a Demon puts its soul into a human body, the demon soul is stronger so it eats the human soul and takes control of the body. However when an angel/devil puts its soul into the human body, the opposite happens: The human soul eats the angel/devil soul and retains control of the body. This is because the Abyss (originally the Elemental Chaos) is more strongly tied to physical reality than the celestial realms (the Nine Hells is a Celestial realm in all but name) which are more tied to a spiritual reality. The Material realm is in the middle in terms of both spiritual and physical ties, being more spiritual than the Abyss and more physical than the Celestial realms. Spiritual ties make it easier to hop between planes, since the soul is not so strongly tied to the physical body. Physical ties bind the soul more strongly to the body, which makes plane hopping harder, but also makes it easier to wrest control of a body from its current owner. This is why the war in heaven is possible at all. Being bad at plane-hopping, the Demons are forced to cross over at a number of strategic locations where the barrier between worlds is weak. Most famously the river Styx. That means the Devils can fight them there, as opposed to the battlefield covering the entire Material realm. This is also why there are more clerics to Angels/Devils than Demons. It is easier for Angels/Devils to communicate with their followers than for Demons. [Answer] **Blasphemy! Angels would NEVER possess a human!** Angels would never possess the bodies of the beings that God loves more than any other! God has made it perfectly clear that humans are his favored beings and are to be protected at all costs! His love for them is so great that the angels fear even the *thought* of harm coming to humans! On the other hand that is precisely why demons and devils like to possess humans, because its a big screw you to god! How dare god love humans more than them?! Humans are a bunch of Johnny come lately's! Where the hell were they when we were doing all the hard work!? Afterlife beings possessing humans is the highest form of disobeying and disrespecting God himself. Cosmic wars have been waged over that! Entire hosts of Angels were cast down because of that. "True" Angels would never do it. It is a matter of honor! And if they did... its straight to hell with them! That kind of punishment is good incentive I think. [Answer] Souls were created to become angels. They were not intended to become demons. Souls are naturally sensitive to celestial energy, and someone that dies can quickly become an angel and join the host because their soul will soak up angelic energy. When a devil tries to merge with a human it goes great initially, because souls attract celestial energy. Soon after though, the human soul will drain a substantial portion of the devil's celestial energy, more or less than half depending on soul power, and will be strong enough to fight the demon. The end result is often fairly explosive, and the devil is left greatly weakened regardless. This is made even worse by the fact that a lot of devils are going wildly against celestial power's purpose. They are 'evil' by its reckoning, and more 'evil' the higher rank they get. Humans they possess are often more suited to their power than they, and have an advantage in the fight even if their souls are weaker. When a demon tries to merge with a human they can function fine because demonic energies are incompatible with souls. Extended exposure may break down the barriers and cause unwanted power theft, but various rituals can mitigate those issues by slowly siphoning power away. A homunculus will be designed to be receptive to demonic energy and reject celestial energies. This means that the trial versions are resistant to demonic interference, and excellent hosts for devils. [Answer] Based on this: > > As angelic spirits are basically souls super charged with celestial energy, they should be directly compatible with human souls. > > > the simplest explanation would be that **angelic souls have so much energy that humans are incapable of containing it**. An artificial soul, a homunculus, can either have a higher capacity or can have some kind of built-in protection. Perhaps, this soul can vent extra energy (this would result in the weakening of a devil, though). Demons do not face this problem because the charge contained in a demonic soul is insufficient to cause the destruction of a human soul. --- *A side note* Possession usually means possession of a body by suppression or elimination of the host's soul. It seems that the demonic possession you describe is consistent with this notion. Is it absolutely necessary for angelic beings to be able to possess a soul instead of a body? Does soul possession work like soul merging? [Answer] **Demons get them right away.** Demons can possess humans with some effort. Angels and devils can too. However when an angel or devil possesses the human, the situation lasts for about a minute and then a demon moves in. The hard work of possession has been done by the angel or devil. The vessel is now not only open for a demon to walk in with no effort at all, but a much more attractive target because the usurping demon will also get the powers of the angel or devil which is then trapped in the human body. Angels and devils don't have much defense against this. Demons are always watching for this kind of great opportunity and the reason the demon does not move in faster is usually there is more than one trying, and it takes a few seconds for them all to sort things out. Demons will do this to each other too if they can. Demons are always fighting with each other and they are good at it. A demon possessor might have to ward off incursions by its fellow demons but usually the owner stays put. Possession is 9/10ths of the law. [Answer] Possession is like an infection: it happens in stages. When a devil or demon first tries to possess someone, the soul fights back, first with its innate immune system, then with its adaptable one should the possession get that far. A successful possession means the soul is dead but the body is not, and thus free to be puppeted around. (As a result, the final salvo of the spiritual immune system involves ramping up the material one to lethal levels - once the fever sets in, its too late.) God, in Their Infinite Wisdom, was able to tailor Their creations' innate immune system to recognize every devil (and angel, just in case) as an infectious agent. As a bonus, it allows angels and devils to touch each other without material reality, and prevents them from merging together into some monstrous host that could rival God Themself in power. Demons, on the other hand, are infinite in number and constantly evolving besides, so even in Their Infinite Wisdom, God could not tailor the innate immune system to target every possible demon. This is why the adaptable system even exists in the first place, to counter demonic possession. Once a demon tries and fails to possess a human, that demon cannot possess that human ever again. The devils' plot to build a homunculus is basically trying to breed a human whose soul has no immune system, which may very well be impossible, and is very risky besides: a prime target for demons, who love taking the easy way out, or even a pre-emptive possession by an angel if God Themself doesn't smite the poor creature dead so their body can't be used. ]
[Question] [ my question is literally right there. the general amount of people is about 2500 people. 1000 are men, 1000 are women, and 500 are kids. whatever farm area amount is required, I won't mind. as long as it isn't absolutely ridiculous. the era is generally in the medieval era. I just need to know if a diet of egg, chicken, rice, beans, and potatoes is livable or not. or maybe there is an online tool I could use to see if this is possible? any other information you need/request I will go ahead and add in. people have been mentioning that rice and potatoes weren't in the medieval era together, or at least weren't grown in the medieval era together, and i am here to mention that while the "kingdom"(people have also mentioned this is more of a county than a kingdom) is generally based off medieval, this is also a completely fantasy world. the other part is the fact that potatoes and rice can't be grown together due to different conditions, and to that, i would like to ask: can a 20 degrees fahrenheit lower half of the year and 20 degrees fahrenheit higher half of a year, where the half way mark is 60, (so its about 80 degrees at its highest, and 40 degrees at its lowest) be suitable to grow potatoes during the warmer season, and rice during the colder season? it never gets below freezing but it does get cooler during the "void moons" one of the two ingame seasons. the other bit of requested info was the landscape due to me mentioning the foraging and gathering. i've imagined this place as being a very open plain with shrubs and the occasional tree, due to deforesting for housing, and supplies, and space for farm land, before reaching an immediate forest about 10 miles out. in the lower sections of the plains is just wetlands and in the higher areas is dryland. so i guess we could add fish to the diet. about animals, i'd say there are just hare's, and a few types of canine in the forest, and deer, and general pesky fantasy monsters we don't need to worry about, cause they're made of magic. [Answer] Your culture can survive on these staples, however for what we call complete nutrition today, you would do well to add a leafy green, a root vegetable other than the potato, a cultivated berry (for a more reliable and plentiful supply than foraging), an ungulate like a goat, camel, or cow, and some fish or shellfish. Your listed foods are going to cover the macronutrients (major sources of calories; carbs, protein and fat) with no problem. Most historical cultures only had one staple carbohydrate source, so to have two makes you that much more protected from famine. The anachronism and cultural difficulties of cultivating rice and potatoes have been covered by other answers, suffice to say, consider wheat instead of rice or yams instead of potatoes. There are 13 essential vitamins, of which you're only going to have trouble with three. The egg yolks are going to provide you with most of these vitamins, while grains will round out the majority of B-complex vitamins, and you'll get a vitamin here or there across the rest of your listed foods. Vitamin B9 (folic acid) and Vitamin K are normally produced in ample amounts by the human body, but a little extra of either never hurt, especially for pregnant women and young children. However, the only listed food they'll be found in are the livers of your chickens; one or maybe two chickens will feed quite a large family, but the livers would only be big enough to give each family member a small bite, requiring you to prioritize. Consider a leafy green like a lettuce variety, arugula, mustard greens, spinach or cabbage, depending on average daytime temperature. All of these contain both of these vitamins in abundance and don't require killing too many of your egg-layers just for liver. That liver is also your best listed source of Vitamin A, though egg yolks have quite a bit of both Vitamin A and of "carotenoid" precursors that can be converted into the vitamin. A red to orange root vegetable like carrots, beets or yams have good carotenoid content, as does the spinach already mentioned, and various gourd-family fruits like zucchini, butternut squash and pumpkin. The third is Vitamin C, which is found in most species of edible berry, including currants, blackberries, raspberries and blueberries among others, all of which are native to most of the northern hemisphere. Consider cultivating these for a more plentiful supply; as native vines and bushes, they're not hard to grow where you want them, don't require much attention, and can thrive in rockier areas of your farmland that aren't suitable for other crops, or as hedgerows between farmed plots. There are 16 essential minerals in modern nutrition, most of which you are going to have no trouble with between the chicken and the beans. One major one you're going to miss with what you have is soluble calcium. The most common source today is in milk, and you have no milk producer in your list. Legumes and leafy greens give you a little calcium, but it's a mineral that vegetarians and especially vegans historically struggled with until soybean products became more widespread in Western agriculture and cuisine. A herd of goats don't take much room, can eat a variety of vegetable matter including grass, and produce a milk very rich in calcium and other vitamins and minerals. In addition to the milk, bone meal, made simply by drying and grinding the bones and gizzards of the animals you slaughter for meat, has historically been an important source of calcium, both dietary and as fertilizer (which gets calcium into your crops and thus into your diet). Also keep in mind that the goats (and other mammals) have to give birth regularly to keep lactating, and that only female goats are really useful for this purpose beyond a couple of rams to keep the female goats pregnant. So, much like your chickens, farmers artificially keep a very female-heavy population by culling the males for meat, giving you a second good protein source (and a red meat like mutton is more nutrient-dense than chicken). The goat skins are also a key source of leather, which is critical to medieval technology above and beyond your nutritional needs. Sheep are another good option especially in colder weather, as you not only get milk, meat, skins etc but also wool (there are hairier breeds of goat, but mohair is a relative niche fiber compared to wool). Another key mineral source you may struggle with in a more inland area is salt, which provides the key electrolyte ions sodium and chlorine. This is normally trivial to get in abundance for any culture with access to the ocean, since all you have to do is boil clean seawater dry and presto, sea salt. However, it can be more of a challenge to get sufficient salt intake in more inland areas. The saltier the soil, the less fertile it is, and while there are salt mines dating back to 5000 BC, these aren't nice places to work for a variety of reasons (historically they were mined by slaves or prisoners with *extremely* short life expectancies) and aren't found everywhere humanity has settled, so a landlocked haven for a medieval European farming culture is going to produce ample but very low-sodium produce, and will have to trade for its salt. The East Asian answer is soybeans, but these didn't spread out of Asia as a food crop until the late 1700s, and most of their sodium content as a foodstuff comes from boiling them in seawater to extract and neutralize their trypsin inhibitors; boiling anything else in that much salt is going to put plenty of it in the food. You can get enough of these electrolytes with a meat-rich diet, or by drinking a sparing amount of animal blood (blood plasma is by definition an isotonic solution of electrolytes, but human digestive systems don't process whole blood very well), but if chicken is your only animal protein it will be a bit harder to manage. The easiest and least gory answer all around is to make sure you give your fictional community good access to a body of salt water. The last one you *could* have some trouble with is iodine. Essential for proper thyroid function, in turn regulating growth and metabolism, you can get enough of it as long as the soil you grow your staples and vegetables in is iodine-rich. Geographical regions to avoid on Earth include sub-Saharan Africa and heavily mountainous regions; almost anywhere else on the planet, especially in coastal wetlands, you'll get sufficient iodine from vegetables and grains grown in the local soil, but fish or shellfish like mussels would be an ideal addition to your group's diet for a little extra. [Answer] Yes, but there are some issues For one thing, potatoes did not appear in Afro-Eurasia until after the Middle Ages, with the Columbian Exchange. When potatoes were introduced to Northern Europe it led to a population boom that may have contributed to the Industrial Revolution. Potatoes are far more efficient in terms of calories per acre than any old world crop. Beans are very nutritious, and chickens provide extremely valuable protein. Rice feeds billions for a reason. It stores very well and is a good source of carbs. But the issue with growing rice and potatoes is that they usually don’t grow in the same conditions. Rice needs a lot of water and doesn’t like the cold. Potatoes on the other hand don’t do as well in very wet and hot places. But this is not insurmountable, as with the right strains of rice and the right strain of potatoes alongside field management you would be able to have plenty of both. You also really don’t have that many people at all, it’s absolutely tiny for a kingdom. The hunting and foraging is extremely dependent on the environment. If it’s a rich temperate or subtropical forest with plenty of water access than they would be absolutely golden. If it’s the Sahara or Siberian tundra things would be harder [Answer] Technically a person can survive well into adulthood without any major health issues off of just eggs and potatoes; though, cholesterol may become an issue when older. I addressed this in a bit more detail in this previous question: [How long can humans survive on this diet?](https://worldbuilding.stackexchange.com/questions/115836/how-long-can-humans-survive-on-this-diet/148977#148977) If you are adding on top of this general hunting and foraging then your people will definately be fine. Since people will instinctively seek out any nutrients they may be lacking when looking for food; so, if you've missed something, there is a good chance you will get enough of it to remain healthy in the things you forage for. Frankly, what you've described is actually a very idealized situation for a medieval settlement. The population is big enough to discourage raiders, but small enough to maintain good sanitation without modern plumbing. You have nearby access to wetlands, highlands, and forests; so, you have a great diversity of natural resources at your disposal. These people will probably be a lot more well off than your average medieval folks. **Two issues I see though:** 1: The region is probably too wet and temperate to support potatoes. I've tried growing potatoes in a climate similar to what you are describing, and if the random heat wave doesn't kill them, temperate zone fungi will. Sweet potatoes however are much more suited to the tropical and temperate zones; so, if your swap potatoes for sweet potatoes, you'll add a lot of plausibility to your setup. 2: This is a likely size for a fiefdom, but not a kingdom. Settlements that size would have been large enough to ward off the standard Viking raid, but they would not have been large enough to maintain their independence. In the medieval feudal system, this place is probably governed by a well-to-do knight, sheriff, or lesser lord who would have "king like authority" over the people, but would himself be subservient to higher ranking lords. ]
[Question] [ In my world, a "perfect" robotic eyeball has been created. This eyeball is electronic, but it emulates a human eye perfectly. This does not necessarily mean that it has millions of synthetic cones and rods and is physically identically to a normal eye; it just means that whatever it sees, a human with average eye sight would see as well. A common problem I have seen with cameras is that they never seem to capture the world exactly the way that people see it; there's always something wrong. Whether it's slightly off-color, the brightness or contrast is wrong, etc. This robotic eye would avoid all of those problems. It would even avoid that weird [moiré](https://en.wikipedia.org/wiki/Moir%C3%A9_pattern) effect when pointed at a computer screen. --- # Is this at all possible? I am aware some people are colorblind; these robotic eyes would see all of the colors the way an average healthy human being without any eye conditions would see them. Assume that technology is like that of modern-day. Also assume that money and resources are no object. --- UPDATE: The eyeball isn't intended to interact with human beings. The whole point is to have robots and cameras that work the same way human eyes do or even better. This robotic eye would even be able to emulate peripheral vision. --- In my story, an eye like this is important for several reasons: * Robots being able to understand humans and how they perceive the world * Being able to render captured footage (whether on a screen, or with virtual reality, etc.) in a way that can be visualized as though you saw it yourself through your own eyes Footage through a camera like this should look real. There should not be a "This is just a video, I can tell because X,Y,Z". It should be virtually indistinguishable from reality to human beings. (assuming that high enough resolutions are available) [Answer] > > Is this at all possible? > > > Yes. Eyes demonstrate that such a thing is possible. Making photosensors equivalent to our rods and cones is a Simple Matter Of Science And Engineering. > > Assume that technology like that of modern-day > > > No. We can't even transplant a real eye yet. Emulating a whole eye in hardware and splicing it into an optic nerve is clearly a more difficult task. --- *edit following question update* > > The whole point is to have robots and cameras that work the same way human eyes do > > > You've conflated two things here... having cameras that give identical performance to human eyes, and having a vision system that works as well as a human's. The camera bit is an engineering problem... getting the exact same colour response might be a bit fiddly, but entirely solvable. Getting the same dynamic range would be harder, but there's no obvious reason that could not be solved either. The *vision* bit is an AI-hard problem, and with all the power and money in the world we haven't been able to crack it. Eyes are, for the most part, a bit rubbish. They work so well *for us* because they are attached to a fairly powerful bit of image processing wetware. > > or even better. > > > Then don't make them work like human eyes. What's the point? You're not piping the output into a human brain, so there's nothing to gain. [Answer] ## We can already make cameras way better than human eyes Human eyes are piss poor optical devices. Our problem with transplanting eyes is the electronics and neural connection not the eye itself, that part is easy. You don't want a camera that sees as well as the human eye, the human eye is shit, it is full of artifacts, distortion, and limitation that have to be edited out by the brain. the moire effect can be solved just by not using digital output for your camera or scanning, just have it output continuously and have dedicated integration after the effect. Human eyes feel better because our brain is used to our existing editing if it has to do more it stands out. If you transplanted an eye from one human to another it will also feel horribly distorted until their brain learns to edit the information coming from the new eye. Color is even more obvious, human color vision is crap, cameras can be built to detect many many discrete colors while the human eye/brain has to composite together what is basically only 2.5-3 vague colors. Even many animals (birds and reptiles) have better color vision than humans, just because they see base 4 colors. we build cameras to compliment human eye color bias but we don't have to build them that way. Don't confuse the average video with what video is capable of, most video suffers because they are projected on a flat surface which then has to be resenses by our eyes, while normally our eyes see independent 3D objects, it is an issue of playback not the cameras. Now the human eye does have a few advantages a curved sensor combined with a curved lens gives less distortion, and only the highest end cameras can compete with human pixel density (not that we use it all). but those are all fixable. But most of what you mention is software not hardware, peripheral vision for instance is software not hardware. [Answer] No, it's not possible, but only because you defined it that way. You focus greatly on an optical device with *precisely* the optical behaviors of an organic object. As a general pattern, this cannot be done. Given a particular metric as to what sort of imaging you want, you may be able to do better, but to do *precisely* the same as an organic eyeball calls for an organic eyeball. This answer is predicated on your requirement of not post-processing the image. With that requirement in place, you're basically stuck. The particular quirks of any organic system are hard to mimic. It's much easier to post process the effects in. For example, consider the rods. The pigment responsible for our low light vision is [Rhodopsin](https://en.wikipedia.org/wiki/Rhodopsin). It's in a fantastic feedback loop with very precise behaviors. A flash of bright light ruins the calibration of these systems, which is why you lose night vision if exposed to a bright light. It's basically insensitive to red, which is why red lights don't hurt your dark vision. Once tuned, these rods are so sensitive that biologists seriously consider that it might be meaningfully sensitive to single photons. This precise behavior will be almost completely impossible to replicate. It's too exacting of a system. What we would do instead is come up with a system with better performance than rods and their Rhodopsin, and post-process some of the fidelity away. Any robotic eye meeting your criteria would be, in fact, a synthetically grown human eyeball grown from human cells, just like ours. That's just the best you can do. *As an aside. You mention the color is wrong. Most of the time the color is more correct than it is for your eyeballs. What you're experiencing is the extraordinary color balancing abilities of our visual cortex. The visual cortex covers for the eyeball a lot!* ]
[Question] [ Say I've got a creature with a 15 to 20 degrees Fahrenheit higher body temperature than a human. (Trying to figure out what a good temperature for this creature would be. Not good with number estimates so I'm unsure of what exact temperature I need for this particular creature.) Would it be less vulnerable to a cold environment because its body is warmer, or more vulnerable because said cold environment's temperature is farther away from its normal body temperature? What would the temperature feel like to a human touching its skin? At this body temperature would it's blood make steam when exposed to earth's air?(I'm hoping not. That would get to much attention since he's trying to blend in.) [Answer] You are such a creature. The skin of your face can be exposed to 0 Celsius when you are 37C. That's almost 40C difference. What happens is you got skin and fat. Also clothes. What happens when sea mammals swim in cold water? They use a combo of fur and fat to insulate themselves. The other stuff is the same as you touching a lizard. Feels cold but it doesn't hurt. [Answer] Your body works on a lot of chemistry and enzymes. These are mostly built with about the same optimum temperature, in our bodies 37° celsius. Hypothermia occurs when the temperature goes so far off this ideal temperature that these enzymes break down or stop and chemical reactions stop functioning properly. Your hotter creature can be assumed to have similar degree difference before his processes grind to a halt as a human, which would be 2 degrees lower than the ideal temperature if I read [this source correctly](https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682). This would count for your hotter creature too. As you mentioned, because the difference in body temperature to background temperature is higher the warmer creature would lose heat faster if they have the same skin type, surface area, and amount of clothing, and reach hypothermia faster. Additionally, the higher base temperature would take more energy to maintain causing the hotter creature to lose its energy reserves and fail to keep his temperature up. \*note, this is for the core temperature. There are lots of processes that can handle larger differences. Your hands are often colder than 10 degrees in winter for extended periods of time and don't die off instantly. It is processes like heart, liver, kidney and brain function which don’t handle low temperatures. [Answer] # Birds Chickens have a body temperature averaging around 42 C / 107 F - that's about ten degrees higher than humans. Some birds like the [sombre hummingbird](https://en.wikipedia.org/wiki/Sombre_hummingbird) can reach as high as 113 F (about 15 degrees higher than humans - as cited by [this study](https://www.researchgate.net/publication/265116100_An_Analysis_of_the_Body_Temperatures_of_Birds)). # Warm Blooded Creatures As @Gustavo and @Demigan point point out in their answers, warm blooded creatures can adapt to external temperature changes by generating heat automatically to counteract the cold. Furthermore, mammals have really good insulation properties (skin, fat). It should be noted that smaller creatures (birds, cats, etc) tend to have higher heart rates and respiration (breath faster), while larger creatures have slower heart rates and respiration. This likely is a factor in ideal body temperature as the faster the heart rate the more heat generated. The key is to get heat out of you (sweat, breathing) when temperatures rise and generate heat within you when temperatures fall. In creatures with no sweat glands (like dogs), panting becomes the only method of heat dissipation and makes them more susceptible to danger at higher temperatures - not to mention their fur prevents heat loss more than less hairy animals (like humans). So if your creature is warm-blooded, their heart rate, respiration, and sweat mechanisms would have a delayed kick-in at higher temperatures, but would kick in faster as temperatures fall. # Extreme Temperatures A bit of an aside, but some animals can survive in extreme temperatures. [This is a fascinating article](https://blog.nationalgeographic.org/2014/07/30/5-animals-that-can-take-the-extreme-heat-and-cold/) by National Geographic which overviews how this works in some animals; it's an enlightening read which might give you ideas. ]
[Question] [ The Elves in my world are plant-like in nature and have the ability to morph and change their skin and body structure as they desire. As a result, Elves can essentially grow their own clothes, by creating a layer of thick bark or create tiny strands of fiber and weaving them into a thread. Appearance wise, it would mimic clothes, but it would act similar to hair, allowing the elves to sense things, but not feel pain if it was damaged. I was wondering if there would be any significant advantage in wearing clothes like humans instead of growing their own clothes? [Answer] Fashion is the engine that drove the industrial revolution. It is quite simply the fastest changing desire that stretches and pushes the industrial, scientific, and and economic capabilities of a people. You could get a similar effect by having accouterments likes hammers, staves, houses, etc.. but these change over the course of decades, where as clothes can be more reasonably changed on short time scales. The rich could reasonably do this daily, or every few weeks/months. The poor are generally forced to update every 2 or 3 years. Clothes wear out faster than most things. Without Fashion your people will either be quite drab, or find alternate outlets such as music, painting, or massive amounts of jewellery to express themselves. Either way it will likely have a negative impact on your peoples productivity as the tools, and means of production for clothes are similar for many other useful things: bags, sails, tents, and armour. More so with industrialisation like the similarity between the early manual machines for spinning yarn, and potters wheels. Where as painting, music, and jewellery have much fewer such translations. --- Privacy. Humans have moles, scars, freckles, discolourations, rashes, etc... all over their skins. While your elven race seems to have some conscious control over their skins they too will be afflicted by defects. Defects that can cause them ridicule, or worse expose an actual weakness. They will even pay for their own mistakes. What five year old doesn't want a unicorn on their shoulder, that they still want when they are 35? Simply to avoid embarrassment and/or questions later in life, many elves would wear clothes, even if their skin were flawless. The society might even evolve to prize flawless skin in a partner. After all, it is a loud declaration of an elf who takes care of themselves. To take care of themselves, clothing to prevent flaws is a no brainer. --- Status. A king wears a crown not because they like wearing a metal collar above their ears. They were it to signal to all around them that they are in charge. Similarly your elves will have need of such symbols. You could get away with beads, jewels, staves, etc... for some jobs, but most jobs have limitations. A doctor needs both hands for surgery, a cook needs something that won't fall into the food, etc... The most energy efficient and practical tool for signalling is often a garment of some sort, as it provides a large signal (it covers the whole body) while also not requiring to be held. It provides some modicum of protection from the dangers of the job, while also staying firmly attached to the wearer. [Answer] The problem with growing your own cover, be it a fur or a bark, is that is gets specialized to counter the challenges of the environment where you live: if you are a seal in the North Sea it will protect you from the cold and wet marine environment, if you are a cork oak it will protect you from the frequent fires, and so on. But take a seal and put it in a fire, or take a cork oak and soak it into the North Sea, and they will both die. Clothes instead can be adapted to the environment: a wet suit will do in the North Sea, and a fireproof suit will do in the fire. If your elves are plant like also in that they have roots, then I don't think they are going to travel that much, thus clothes might not bring significant advantages. If instead they can travel, clothes can provide additional adaptability. [Answer] # Worn Clothes are items that can be taken off, shared, sold, repaired and reused Having grown clothes means they are attached to your body. That means that if you grow a shirt, you can't easily take off that shirt and hand it to someone else. It means you can't sell your clothes if they get too big (or if there is a market for second-hand clothing). it means you can't easily repair it if it gets dirty or damaged, because you need to be present to do so. It means that if you wear a specific shirt today, and you want to wear a sweater tomorrow, you can't easily wear the same shirt the next day. In the end, worn clothes provide flexibility: unless your species can grow entirely new clothes in minutes, you can't easily replace grown clothes. # Grown clothes cost extra energy to grow. Grown clothes means your body needs to somehow grow each individual hair to the right length. This takes energy. Growing a tuxedo worth of clothes would probably cost a lot of energy. That's energy you can't spend doing other stuff, or energy that needs to be additionally harvested from whatever it is your elves eat. ]
[Question] [ **This question already has answers here**: [How would you make a universal measurement of time?](/questions/106030/how-would-you-make-a-universal-measurement-of-time) (6 answers) Closed 4 years ago. In my novel, I have created an intergalactic empire that predates humanity by millions of years. The only system I am having a difficult time creating, for this empire, is a Calendar system that operates off of cycles of the universe; not of a local planet. However, finding information about the cycles of the universe is like looking for a needle in a haystack. Does anyone have any information about the cycles of the universe that might be helpful for creating a kind of intergalactic calendar? In my system there should be an intergalactic date, a planet symbol, and then base a calendar off that planet so that there’s five sets of digits in the dating system. For example: * galactic year - GY (?) * Planet - P (which planet) * Local Year - LY (planetary year) * Local Cycle - LC (planetary month) * Local Sub-Cycle - LSC (planetary day) Time is based on a UTC type of synchronization using what amounts to an atomic clock when in space which is synchronized to a local planetary subdivision of a day using a base of that planet's cycles, such as a base 10, base 12, base 24, base 30, base 100, etc. - a numeral system for pre-colonized worlds such as earth. * day (light / dark cycle) * hour (large time grouping) * minute (medium time grouping) * second (small time grouping) * millisecond (tiny time grouping) The empire is highly advanced and logical so I want to ensure the logic applies also to their calendar system. Any suggestions or recommendations are greatly appreciated. Edit: This question is about observable phenomena in the universe that could be measured and used for time keeping, it's not a question of how to make a calendar. 200 million years per revolution of the milky way is on the right path. How about cycles of the universe as a whole? [Answer] **Use the frequency of relic radiation to determine time since the Big Bang.** Relic radiation (a cooler term for a fiction than Cosmic Microwave Background, I think)is detectable everywhere in the universe. The frequency of this radiation has gradually been redshifting since its origin shortly after the Big Bang. The observed frequency corresponds to how long it has been since the Big Bang. It does not matter where you are. The frequency of relic radiation could be used as a date. <https://en.wikipedia.org/wiki/Cosmic_microwave_background> > > The cosmic microwave background (CMB, CMBR), in Big Bang cosmology, is > electromagnetic radiation as a remnant from an early stage of the > universe, also known as "relic radiation". The CMB is faint cosmic > background radiation filling all space. It is an important source of > data on the early universe because it is the oldest electromagnetic > radiation in the universe, dating to the epoch of recombination... The > accidental discovery of the CMB in 1964 by American radio astronomers > Arno Penzias and Robert Wilson... and earned the discoverers the 1978 > Nobel Prize in Physics. > > > CMB is landmark evidence of the Big Bang origin of the universe. When > the universe was young, before the formation of stars and planets, it > was denser, much hotter, and filled with a uniform glow from a > white-hot fog of hydrogen plasma... The photons that existed at the > time of photon decoupling have been propagating ever since, though > growing fainter and less energetic, since the expansion of space > causes their wavelength to increase over time (and wavelength is > inversely proportional to energy according to Planck's relation). This > is the source of the alternative term **relic radiation**... > > > Assuming the universe keeps expanding and it does not suffer a Big > Crunch, a Big Rip, or another similar fate, the cosmic microwave > background will continue redshifting until it will no longer be > detectable > > > The amount of redshift present at any given time corresponds to the time since the radiation originated. Time travelers emerging into an unknown epoch could take a reading of relic radiation and use detected frequencies to calculate when they had arrived. --- [Answer] As pointed out rather neatly by @PiggyChu001, time changes relative to the (among other things) gravitational differences near the sources of two clocks. In fact, it changes according to this linear equation: $ t\_a = t\_r \* \sqrt{1-\frac{2GM}{rc^2}}$ where ta is the actual time, tr is the recorded time (at your position in space), r is the distance from the object causing the gravity, and $ \frac{2G}{c^2} $ is just a constant. The fun part about this is that it comes from special relativity, and [experiments at Harvard](https://en.wikipedia.org/wiki/Pound%E2%80%93Rebka_experiment) show that this is a direct result of special relativity acting on space-time. The upshot of this for you is **time is affected only by the magnitude and direction of gravitational forces acting upon it.** If you can calculate the strength of a gravitational field within a system, as well as its centre, you can substitute Newton's Law of Universal Gravitation: $ F\_r = \frac{Gm\_1m\_2}{d^2}$ to find the resultant force and singularity of your local gravitational field (repeat for every mass in your field to get one universal result). **You can then normalise the time between any two points in your galactic empire** by plugging in the time at one end (ta), calculating the relative difference in gravitational field strength (change $ \frac{2GM}{rc^2} $ to $ \frac{2gr}{c^2} $, where g is your local field strength and r is the distance from the point where this field has a net force of zero) and bob's your uncle. A year at the Galactic capital can be converted into a year on the frontier. Use atomic clocks for best accuracy (caesium is always a reliable choice), and again make sure to account for the difference in local field strengths. In reality, you'll need to take into account gravitational red shift due to the expanding universe, but for world building the above is mathematically justifiable. Hope it helps in your quest for Galactic domination! [Answer] Finding this kind of "Standard Time System" is next to impossible! Because, like it or not, "time" is actually all "relative"! **"Every"** planet has its own speed of time due to [the difference of the gravity](https://en.wikipedia.org/wiki/Gravitational_time_dilation#targetText=Gravitational%20time%20dilation%20is%20a,)%2C%20the%20faster%20time%20passes.). Even if you have come up with some system for the empire people to follow, the time in Planet A **WILL** be different from the time in Planet B! For example a year in Planet A is actually 13 months in Planet B! Even though the said difference will be "VERY" small! But it will add up eventually! Especially if your empire had existed for so long (millions of years), that difference will definitely be quite significant! Unless you had come up with some kind of device or something to take the [**`Gravitational Time Dilation`**](https://en.wikipedia.org/wiki/Gravitational_time_dilation#targetText=Gravitational%20time%20dilation%20is%20a,)%2C%20the%20faster%20time%20passes.) into account and adjust "the length of unit time", in other words, "the speed of time" accordingly, the time in your empire "**WON'T**" be synchronized! [Answer] You are going to have a problem there because a galactic empire by definition spans a space that is hundreds of thousands of light years across. Relativity plays a more important role in measuring time when you consider this, because things far away from you may be moving at relativistic speeds relative to you. For example, S2 can reach orbital speeds of up to 5,000 km/s (compare with Mercuy's tame 47.6 km/s). That's 1/60th of the speed of light. Someone on a planet orbiting S2 will measure time differently than someone on Earth. Enter a thing called [**relativity of simultaneity**](https://en.wikipedia.org/wiki/Relativity_of_simultaneity). If you want the full mathematical elaboration of the phenomenon, follow the link. In very layman terms, if we are: * Sufficiently far from one another... * And moving relativistically as I described above with Earth and S2... * And we observe the same set of things happening anywhere in the universe... * And those things are not causally connected... Then **we will agree that those things happened, but not in which order**. For example, a supernova happens in Draco while a black hole devours a spaceship in Orion. It may be that, for me, the spaceship was devoured first and the supernova went off later. For you it's the opposite - first the supernova happened, and then the ship fell onto the black hole. --- Given all this, very exact and precise timekeeping on a galactic scale is impossible. What you can do is: * Assign a galaxy rotation period as a galactic year. The Milky Way completes a full rotation every 200 million years, and everyone everywhere can measure that; * Let every planet or star system define its own timekeeping; * Broadcast a signal at fixed intervals from the center of the galaxy, to act as an "exchange rate" of time among different systems. Make sure each signal sent references the previous one in some way, to establish a causal relationship. A simple counter increment will do. When two different systems wish to discuss passage of time, each can compare their own time passing and event order to the cycles of the central broadcast. They can then infer how fast time passes and how order of events differ between them by measuring the comparisons against each other. In such a way, each planet's time will be like a currency in an exchange agency, with the central broadcast acting as the Dollar or Euro of the house. [Answer] Easyer and more universal approach: Take the [planck-time](https://en.m.wikipedia.org/wiki/Planck_time), the smallest physically possible unit of time, figure out what kind of number system they are using and devope something like the [SI-system-prefixes](https://en.m.wikipedia.org/wiki/Metric_prefix). Name the appropriately long time spans creatively and use them like the nearest equivilant. For example let's meet in one qitta-tp (maybe leave out tp, shorthand for Planck time). A qitta is roughly eauivilant to, say 1,3 days or ca. 32 h. A good unit to replace the day with. Use the big bang as t = 0. Alternatively you can do this with the aliens main time unit. I once designed such a system with secounds as my base and the new day had about 27 hours. Such a system is very universal and great for spacecraft and interplanetary affairs. If you megastructure or planet has a rotation and spin time (year and day) that is not so rediculessly short or long that everyone ignores it, it might surplant the galactic system. However for this same reason the physics based system will be superior to the galactic rotation system. A galactic rotation is way too long to be useful and can cause a lot of xanflict because people might measure it differently or fudge with the objects timekeeping is based on to justify some political agenda. Sounds rediculess? Well, the Maja did it. [Answer] # Use Local Time when convenient, and Imperial Time when you must Turns out computers are *really* good at converting between the two. Every species in the empire, and the colonist on every planet, will be adapted to different cycles, so why bother forcing everybody to adapt? Use the local time for local events. This way, Imperial Time can be simple and similar to the way computer time works - the Unix Epoch is measured in seconds since 1970. The computer converts time-in-seconds into whatever year-month-day format the user needs at that particular moment. It doesn't really matter if an Imperial Quarb is a second or a day or a week. My display doesn't show the date to me in Quarbs - it shows me in familiar local Barrfs. Nobody needs to convert *in their head*. If my dentist wants me to get half-Barffly checkups, I'll put the appointment on my local Barff calendar and I'll be there. In the meantime, my space-liner to Rigel is scheduled to arrive at 10385678332 Imperial Quarbs, which my display happily converts into local Barffs/Narffs/Glarffs for me. I'll be there on time, too. Some locations (spaceports, Imperial offices, courts, etc), are likely to have clocks that simply display time in both formats, but that's mostly for show. Some documents will need to use Quarbs to prevent confusion, but so what? Asking the nearest toaster or lamp-post for the current time in *whatever format you like* is trivial. Just like asking your PC or Phone for the time in a different format is trivial for us today. [Answer] The imperial timescale is calculated from a significant point in the imperial history using the calendar of the imperial capital. If you have a communication system that works instantaneously over the full width of the empire then the whole thing becomes moot, the capital broadcasts a time signal. If it takes three years to send a message then it becomes meaningless what the datetime is in the capital. The need for universal time only applies when universal time becomes a necessity. Circular logic yes, but this comes out of railway time. The time the train arrives only matters when it's moving fast enough to matter. If it takes 3 years to get from the capital out to the remote worlds then there's no reason at all to have a matching time calculation, it's barely worth tracking the years. People may know the approximate date in the capital but it's effectively meaningless. This only matters for imperial edicts, which will bear the imperial timestamp. When the edict arrives at the world in question, the local timestamp will be added and the edict applies from that moment. It can't apply before it's received so the actual moment of issuing is irrelevant to the provincial worlds. ]
[Question] [ A god once created a beautiful planet and populated it with all kind of plant and animals. He brought up humans, because no world is complete without them. But then he paused. Not because he needed a rest, no, but because he thought about the future. And the future indeed looked cloudy. His beloved humans would grow and multiply, invent wheel, iron working, steam engine. They would build railroads and factories, pipelines and chemical plants. They would play with nuclear power. What would happen to green hills and blue skies of this world? What would happen to its lesser creatures? Impeding ecological catastrophe looked inevitable. Some other gods say that this is just a necessary step in a civilization growing up, and if ecological damage gets out of hand, a god should step in and punish his subjects with a great flood or something like that. But not this god. So the god sat and thought about how his people can avoid spoiling their world. His powers were immense. He could strip the world of any natural resource, or make it overly abundant. He could change atmospheric composition and move around planets and moons. But his powers were limited too. He couldn't change laws of nature. And he couldn't change the nature of his people. Some other gods say that ignorance is bliss. People are better off living in a garden of Eden, never knowing technology and its poisonous fruits. Maybe going a bit further and living in idyllic Middle Ages. But not this god. He knew better of this so called idyll, and that his subjects deserve better. They deserve progress. But how avoid the dark side of it? So the god just sat and thought, and still could not come up with solution. Can you help him? P.S. The god understands that the term "ecological damage" is fuzzy and some strict criteria are required. So, the god suggests that his subjects should at all times comply with more stringent of Earth-based clean air and water standards. For example, US EPA sets following standards for air pollution: <https://www.epa.gov/criteria-air-pollutants/naaqs-table> [Answer] No. But... simply because the term "ecological damage" is nonsensical. Modern sensibilities equate that term with unpopular human influence on nature. But humans are and always have been as much a part of the planet's ecology as any other living thing. When humans want to dam a river there is much anxiety about the potential for damaging the local ecology. But when beavers dam a river without any regard for the impact it has on the ecology it's accepted by humans as nature running its course. When humans want to build a highway there is anxiety over the destruction of natural habitats. But when herds of elephants cross an African plain trampling plants and ant hills along the way humans find it charming. But in essence there is no difference among them. All are examples of ecology in progress and in particular energy transferring through it. There would be no ecology without energy. (And in the case of Earth energy from the sun.) Since technological evolution as we know it requires transferring energy within the compartment of an ecology there will always be unavoidable "damage" within it. Just as the transferring energies of a thunderstorm "damage" localities that experience its influence. So in that sense there really is no such thing as ecological damage. There will always be unavoidable physical effects of energy flowing through a complex physical system. That which is considered damage is simply an emotional argument subject to the whims of human perspective. [Answer] Technology is not in of itself a damage to nature. Lets look at earth, here the problems comes primarily from forms of greed. We use trawling for fishing, because then we can get 50% (arbitrary amount) more fish, even if it damages the sea floor. Same for most aspects of resource acquisition. It's a philosophy of "It's OK if I can get more now, if the consequences doesn't happen until after I'm dead". So the question should be more along the lines of, Is it possible to create humans, who are selfish enough to strive to improve, but not so much that they will sacrifice future generations for their own benefit. Secondly I suppose a lot of the damage we do to our environment happens because of ignorance. We just didn't know CFC gasses caused damage to the ozone layer, before it was too late. A god that actually bothers to inform and teach us of these consequences before they happen would probably be able to mitigate a LOT of damage to the environment. [Answer] God considered making humans live much longer, say a thousand years each. Maybe then they would be more cautious. God also considered giving them more brains, a higher mental capacity to think ahead and do a risk analysis of what might happen and what one may better not do or just more mirror neurons to show more empathy with their surroundings. God thought that better brains might be dangerous during a hunter-gatherer phase and so he considered additionally giving them inferior physical traits like bad eye sight, slow reactions, ... God also considered changing the biochemistry in the human brain to make them love nature more, by letting the body release higher doses of positive messenger substances when surrounded by nature. God also considered biologically limiting the procreation rate of humans. To this end God experimented with sperms that were mostly defect. God also considered a barren, hostile world were humans would always struggle to survive. Vulcanoes, deserts, ... you name it, God thought about it. God also considered just removing all the stuff that is dangerous. No radioactive material, no coal, no mercury. Finally, God settled on making two almost identical planets next to each other (rotating on nearly the same orbit but half rotation around the local star separated), one with humans and one without. Humans wouldn't be able to move to the second planet unless they were technologically advanced so much that they had ruined the first planet and then they would hopefully have learned the lesson. God really couldn't change the fact that humans only learned after the fact, that's why God sighed and made the two planets. Summary: **Either make life harder for them or give them more brains & less strength and more love or give them a second chance somewhere in the future when the time is ripe.** [Answer] You can't. By the time of bronze age collapse the sumerians and egyptians had alredy messed up the natural environment of Mesopotamia and Nile basin. You don't need modern technology to turn forests and swamps into farmlands and then the farmland into a salt marsh, like the old farmlands of Ur. All human activity will upset the environment. What your god needs to do is to decide what is better: a world filled with humans or the green hills. Edit: "idyllic" hunter-gatherers were able to hunt megafauna to the brink of extinction, like the mamooths and, if i remember correctly, the horses in America. So, keeping the humans in the neolithic won't work. [Answer] Technology **is** changing the environment All tech involves some kind of change. Collecting rainwater sounds harmless, but ... * Can result in stagnant water and thus water-born diseases * Result in changing the water table * Affect the details of run-off and may either reduce or enhance flooding * Requires materials to store rainwater, or land to submerge Virtually all technologies produce heat. Heat itself can be a pollutant. [Answer] As other said, any technology will change the ecosystem. Prehistoric humans used fire and tools to hunt mammoth into extinction, along with other large animals. Any kind of agriculture replaces natural ecosystem. In fact, even evolution of animals changes the ecosystem. Mammals have driven dinosaurs into extinction. So your God would have to decide what kind of change to ecosystem is acceptable, and what isn't. A few ideas, following real-world governments: * Declare certain areas, rivers and species as sacred, so they should be left alone. * Require fishermen to return a quarter of the catch to the water, and farmers should leave a quarter of their lands wild, as a tribute to their god. * Mining, metalurgy and chemical industry make some pollution inevitable. Require workers to do their best to filter pollution, and the company must donate to monasteries or buy land and keep it wild (i.e. Pigouvian tax) [Answer] Feed the humans information and technology that allows them to skip the more destructive aspects of civilization. Better farming techniques and better plants being cultivated (ie, have more tolerance for environmental variations plus greater food output per plant) means less ground needs to be cultivated to support the same number of people. Better farming technology means fewer people are necessary to produce the same amount of food. Combine that with greater health knowledge allowing greater survival of children and women in childbirth means farmers don't have to keep pumping out more kids to both make up for the ones that don't survive and to supply enough workers to do the farming (traditional farming depends on child labour). That helps manage population rise while also reducing the requirements to create more and more farmland, which will have benefits in preserving natural areas. Encourage urbanization, because urban areas are far more efficient in supporting populations; ten families spread out over a few square kilometers require more resources than ten families in a small area where they can share services; among other things, urbanization reduces the needs for things like roads. The roads connect the urban areas, they aren't sprawled out all over the country because the population is scattered. Get to electricity as soon as possible; electrical generation can come from a huge variety of energy sources, which allows you to choose the ones that will have the least impact; windmills in windy areas, hydroelectric for people near areas where that's appropriate. Even if your source is a coal-fired generator, it's easier to control the pollution from one single source than if every home has its own coal furnace. Essentially, your deity's overall goal should be to get them to early 21st century technology as soon as possible. You can see this sort of thing in less developed areas of the world, where people are skipping, essentially, the more destructive aspects of the industrial revolution (big coal-spewing industries, environmentally destructive mining involving stripping everything away and dumping whatever wherever) and going straight to tech that's less harmful because it's more efficient. And since said deity is active anyway, the odd lightning bolt that fries some idiot who thinks the proper way of dealing with garbage is just dumping it at sea would make a useful object lesson. "Thou shalt reduce thine impact on the environment lest thou get thine ass kicked" would be a useful commandment. ]
[Question] [ I've got a variation of 'humans' who have superior strength on average, with the top fourth of their population being comparable to 'The Mountain' from "A Song of Ice and Fire" (Roughly 8' tall and capable of killing a horse with a single punch). In addition to that, they also have a skin that effectively serves to be as effective as regular leather armor. With those clear physical advantages, would this group be able to take a typically 'barbarian' fighting style, counting on their toughened skin to supplant for more common armor? Culturally, they would also have incentives to do so to have body tattoos that they value in display, though they do wear armor if they feel they have to. With equivalent intellect to humans, would a race of humans like these have developed different tendencies in warfare, both amongst each other and against common humans? The tech level is a general medieval fantasy era, though a very primitive sort of gunpowder is present, similar to the one found in medieval China. [Answer] **No.** You haven't changed the status quo. You've just taken a group of thugs and given them leather armor skin and steroids. They're stronger, yes, but strength is already an advantage in combat. There are hundreds of ancient military techniques and formations that were explicitly designed to be used against superior foes (like encircling, using ranged weapons, ambushes, forcing fights on unfamiliar terrain, etc.), so it's unrealistic to expect warfare to drastically change because the already useful parts of it got more useful for one side. Breaking it down, leather skin isn't especially useful if you're setting this in 'traditional medieval fantasy' which means superior metal armor is present and the majority of weapons can pierce basic leather armor from metal arrowheads to pikes to swords. The eight-foot tall bruisers are kind of an interesting concept, considering the average height of a medieval knight was around 5 1/2 feet, but you wind up with anatomical problems (unless you want to magic that stuff away, or something), logistical problems, and finally, they're *giant walking targets.* Literally, they'd stick out like sore thumbs among their regular brethren, and if you had them form elite heavy troops, anti-cavalry tactics like using spearwalls would efficiently shut them down. That said, if you decided to take them a train them in the Macedonian Phalanx and equip them with *twenty* foot spears, then you'd be capable of wrecking any army on flat terrain. But, and here's the most important point, it wouldn't change the way war was conducted. Just tilt the balance. [Answer] Specifically answering the question of whether or not natural leather armor would be sufficient to allow these giants to fight shirtless a la Hollywood barbarians. **No.** *Almost any ranged weapon can pierce leather armor, so they'd get wrecked if they relied 100% on their skin.* If there's any particularly strong trend in history with armor, it's that **soldiers wear as much armor as they can afford** as long as it won't overburden or overheat them. I assume that there would be no significant difference in the form of armor, except that the square-cube law probably means that, although their armor will be thicker than regular people's armor, it will be relatively weaker against their equally-sized opponents. **Weapons technology will probably shift a little in favor of piercing weapons as opposed to blunt or edged, and normal humans will use more polearms**. Edged weapons like swords will be less useful against people with such tough skin. Blunt weapons are normally used because of extremely effective armor, but these giants (that pesky square-cube law) will have relatively weaker armor, which will make it harder for smiths to "beat" piercing weapons and "force" the use of blunt weapons. Blunt weapons and shorter weapons should still be popular at all points for specialist moments like siege assaults (where you won't have room for swinging longer weapons,) and eventually metallurgy and smithing will advance enough to make them the weapons of choice for taking on armored giants. Polearms may be a necessity for regular people to compensate for the reach advantage of the giants. Additionally, **archery may suppress gunpowder for longer**, since these giants will be able to wield immensely powerful bows. And with their proportionately weaker armor, these bows will remain effective for longer. **Heavy cavalry may be delayed** since it will take much longer to breed horses in large numbers that can support the weight of these giants. Overall, I wouldn't expect a dramatic shift, just a longer road before heavy cavalry becomes king of war and a longer road before the advances in armor technology start forcing you to switch to gunpowder. [Answer] Historically, the elites who ruled over the masses of peasants wanted to be seen as something special. "Anointed by god", "blue blood", "descendants of x or z famous guy" or some other invention. Well, our special humans here are special for real! They are something to look up to, for the common man. Like for real, because they are tall. Also stronger. Equal inteligence with humans. And faster, big size does not mean a creature is slow, think bears. They have a natural deep voice from the bigger lungs and throats that make them seem to be more manly. They are good battlefield leaders, they can lead lesser races from the front with lesser actual personal risk. They like to practice duel while naked, and it works with that tough skinn. They do this in impress the weaker races, but also because its a lot more expensive to repair the huge armor they got. In a real battle they always use armor and have the great strenght to effectively wield huge shields. The shields make them almost invulnerable to almost all missiles and hand weapons and can be used as battering rams. Combine this with a 5 meters long one handed pike and you have the finest heavy infantry ever. What could be different in this society, beside the tendency of rulers to be giants ? The development of gunpowder and fire arms. This world has a bigger need for it. A battery of several napoleonic type cannons with shrapnel and grapeshot could devastate a phalanx or shield wall of giant men. The giants could be grenadiers. Historically grenadiers would be selected from the talles strongest men. Not a match for cannons, but deadly at close range, cities, forests, tossing grenades. But not kings of the battlefield anymore. [Answer] First, change the hide specifications for these "barbarian giants". You want: A) Thick skin, maybe with a layer of blubber underneath (for greater protection and cold resistance). A hippo's is two inches thick and makes them quite resistant to bullets (though a 50. cal can apparently kill them with ease) but a sperm whale's is 14 inches thick (good luck shooting a bullet/arrow through *that!*) I'd go with the 14-in. skin. B) Tough skin, think rhino. C) Plated, a la Javan Rhino (I don't know how to put picture links, hopefully you can find a good picture): you see, these guys have built-in "plates"-folds of skin-that make them harder to hurt. D) Scales. If you really want superior protection (*especially* from bullets), look at crocodilians. It's almost *impossible* to get a bullet through their scaly skins, and with the additional toughness granted by the hide-like nature and thickness of their skin, these guys will render firearms (hopefully) useless once they are developed. Both when fighting each other or when fighting other humans, the focus will be on blunt force. Smashing, crushing, and otherwise trauma-inducing attacks will still hurt, if not kill, these individuals. Assuming their toughness evolved to protect them when fighting *against* each other, they would therefore have developed adaptations that make them more resistant to blunt force. This being said, a cannonball or flung boulder (via catapult) should still do the trick. These guys will be like Urgals in Eragon, no, Kulls, due to their large size. Fierce fighters, renowned for combat, *very* hard to beat unless you have cannons and catapults, which smart kingdoms will both acquire and put considerable work into developing. That being said, they will adapt to make up for these weaknesses: 1. Use **Religion**-These giants use propaganda and charismatic preachers to spread the idea that they are blessed, no, *chosen* of the gods to be the superior race, AKA rulers. Religion is a great medium for A) gaining power, B) maintaining power, C) shaping beliefs and values, and D) making authority stronger. Authority crumbles when it's questioned, religion usually comes with anti-questioning principles. This gives them power over everyone, and also enables them to outlaw cannons and catapults as 'unholy.' 2. Use **Sheer Power**-This requires early giants to have had both vision and determination; enough to sieze power early in history and maintain it. People may revolt, but these guys have by now (assuming Dark Ages) *designed* the system to benefit them, culturally, socially, and of course physically. The methods of making cannons and catapults will be well-hidden and restricted, to prevent this weakness from being exploited. 3. Use **Saboteur** and/or **Intimidation**-Elephants are surprisingly silent, having biological "silencers" in their feet. There are also graceful, large animals out there, as evidenced by this quote from the Huffington Post: "Despite their powerful size, bison are graceful creatures and move almost daintily, but with speed and purpose." If these giants have these traits, A) they're not the easy-to-counter slow brutes we typically see in media and B) they can sneak into places. Let's say that when the giants hear someone is working on cannons or catapults, or weapons that would be effective against them, they attempt to put a stop to such nonsense with a show of force. This may work, but you know what's even more effective? Having whoever starts working on such a project assassinated. The resulting 'fear factor' will make anyone reluctant, if not unwilling to, develop anti-giant weaponry. 3. Use **Clever Tactics**-If none of the above work for you, simply have the giants use clever tactics to mitigate cannons and catapults. Account for their weaknesses the same way regular humans do; through *intelligence.* ]
[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. **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/151398/edit). Closed 4 years ago. [Improve this question](/posts/151398/edit) It seems the Fraxians, an alien race from Alpha Centuri, have been secretly watching our television ever since we started broadcasting it (well technically I suppose 4.367 years after we started broadcasting it). They find Earthlings quite amusing, with the bizarre way we move using only two limbs, how funny we look with our bilateral symmetry, our absurd misunderstandings of science, and the adorable way we always depict other aliens as looking like us even though everyone knows most aliens species actually look more like a cross between a cat and a jelly fish. They even find it hilarious how we think it would be hard for them to [decode our simple broadcasts](https://worldbuilding.stackexchange.com/questions/30471/how-could-a-blind-alien-race-interpret-video-broadcast-into-space). However, this whole "is Pluto a planet" debate has just been so annoying for them to watch. If you ask their astronomers about Pluto they would tell you the debate is pointless since Pluto is clearly a wco'ad-lkod (sadly the word doesn't translate as well into the English language). Having gotten sick of the debate the Fraxians have decided to end it once and for all, by destroying Pluto so no one needs to decide what to call it. So the Fraxians have re-purposed the Earthling-containment ray, originally intended to avoid human's contaminating the rest of the universe by destroy Earth the moment it looked like we may achieve interstellar travel. The Containment ray has been instead used to destroy Pluto. The entire not-planet has now been struck with enough power to cause Pluto to explode outwards, with piece thrown in every direction at high speed. My question is what happens to earth now that Pluto no longer exists? Would the change in gravitational pull caused by the various pieces of Pluto rapidly changing position have any appreciable affect on the orbits of Earth and it's neighbors? What are the odds that a piece of Pluto makes it all the way to earth and gives us a new sympathy for the dinosaurs? Will we have to rename Mickey Mouses dog!? [Answer] **PART ONE OF SIX: DETECTING THE DISAPPEARANCE OF PLUTO** It seems to me that if Pluto is exploded a lot of the matter in Pluto should turn into glowing gases. Thus the total luminosity of Pluto should increase drastically since it no longer merely reflects light but now also emits light. First possibility: So the next time an amateur astronomer looks at Pluto in a telescope or photographs Pluto, it will appear much brighter than normal. So eventually it will be known that amateur astronomers think that Pluto is much brighter than normal, and professional astronomers will decide to check it out. And they might discover that Pluto is now an expanding globe of glowing gases mixed with solid particles. The most probable, or only, known way for a large body the size of Pluto to explode would be for it to collide with another body with sufficient force. And since the known large bodies in the Solar System have existed for about 4,600,000,000 years without being destroyed in collisions, the odds against such a collision happening to a specific astronomical body during all of human history so far would be - well, "astronomical". Thus many humans will come to believe that the destruction of Pluto was a result of the evolution of humans, that super advanced powerful aliens deliberately destroyed Pluto as some sort of result of their discovery that humans exist. Second Possibility: Alternatively, nobody might look at Pluto until the cloud of glowing gases expands and cools so that it is no longer brighter than the background of outer space at visible wavelengths. So the next time an amateur astronomer looks at Pluto in a telescope or photographs Pluto, they won't see or photograph anything where Pluto should be. So eventually it will be known that amateur astronomers think that Pluto has vanished, and professional astronomers will decide to check it out. And they might discover that Pluto's moons are now moving away from its location on tangents from their former orbits around it, and that the whole volume of space around Pluto's calculated position is filled with an expanding cloud of cooling gases mixed with solid particles that still emit infrared light at temperatures much higher than the cosmic background radiation. The most probable, or only, known way for a large body the size of Pluto to explode would be for it to collide with another body with sufficient force. And since the known large bodies in the Solar System have existed for about 4,600,000,000 years without being destroyed in collisions, the odds against such a collision happening to a specific astronomical body during all of human history so far would be - well, "astronomical". Thus many humans will come to believe that the destruction of Pluto was a result of the evolution of humans, that super advanced powerful aliens deliberately destroyed Pluto as some sort of result of their discovery that humans exist. **added August 12, 2019** **PART TWO: NO PLUTO HOLOCAUST?** What were the effects of the explosions of the First and Second Death Stars on Yavin IV and the moon of Endor? TV Tropes has a trope called No Endor Holocaust where blowing up something large to save the day does not cause widespread casualties and destruction as it might be expected to do. > > The trope is named after a theory that argues the destruction of the second Death Star in Return of the Jedi turned the Ewoks' homeworld, the Forest Moon of Endor, into a smoking wasteland. The Wookieepedia article explains that canonically, the Endor Holocaust did not happen, only existing as Imperial propaganda. Later material would Hand Wave it by explaining that the Death Star's destruction created a wormhole (long story; just know the Death Star was intended for faster-than-light capabilities) that sucked most of the debris (including The Glove of Darth Vader) into parts unknown, with any dangerous leftovers being caught in Rebel tractor beams... > > > <http://www.theforce.net/swtc/holocaust.html>[1](http://www.theforce.net/swtc/holocaust.html) **PART THREE: AN EXPANDING SPHERE OF DEBRIS - A PLUTO CLOUD?** It is obviously possible that one way the aliens might destroy Pluto would be to simply explode it. That would turn Pluto from a solid spheroidal body with a diameter of about 2,376.6 kilometers into an expanding spheroidal cloud of solid, liquid, gaseous, and plasma matter, containing subatomic particles, atoms, molecules, and perhaps pieces of matter of various sizes. When the Pluto cloud has ten times the diameter of Pluto, or 23,766 kilometers, it will have one thousand times the volume Pluto had, and its density will be one thousandth of its former density. When the Pluto cloud has one hundred times the diameter of Pluto, or 237,660 kilometers, it will have one million times the volume Pluto had, and its density will be one millionth of its former density. When the Pluto cloud has one thousand times the diameter of Pluto, or 2,376,600 kilometers, it will have one billion times the volume Pluto had, and its density will be one billionth of its former density. When the Pluto cloud has ten thousand times the diameter of Pluto, or 23,766,000 kilometers, it will have one trillion times the volume Pluto had, and its density will be one trillionth of its former density. When the Pluto cloud has one hundred thousand times the diameter of Pluto, or 237,660,000 kilometers, it will have one quadrillion times the volume Pluto had, and its density will be one quadrillionth of its former density. When the Pluto cloud has one million times the diameter of Pluto, or 2,376,600,000 kilometers, it will have 1,000,000,000,000,000,000 times the volume Pluto had, and its density will be 1/1,000,000,000,000,000,000 of its former density. When the Pluto cloud has ten million times the diameter of Pluto, or 23,766,000,000 kilometers, it will have 1,000,000,000,000,000,000,000 times the volume Pluto had, and its density will be 1/1,000,000,000,000,000,000,000 of its former density. The distance of Pluto from the Sun varies between 4,436,820,000 and 7,375,930,000 kilometers, so the Pluto cloud should reach Earth when the Pluto Cloud is between one million and ten millions times the diameter of Pluto, and thus when the Pluto Cloud has between 1/1,000,000,000,000,000,000 and 1/1,000,000,000,000,000,000,000 the density of Pluto. The density of Pluto is 1.854±0.006 grams per cubic centimeter. The density of Earth's atmosphere at sea level is 0.0012 grams per cubic centimeter, or about 0.0006472 of the density of Pluto. So Earth's atmosphere at sea level is still millions and billions of times thicker than the Pluto cloud will be when it reaches Earth, which is good. Triton, the large moon of Neptune, has a very, very thin atmosphere. It has a pressure of only 14 microbars, or 1/70000 that of Earth's surface pressure, or 0.0000142 of Earth's atmosphere at sea level. And yet it is dense enough to have visible effects, as rising clouds turn horizontal as they reach the wind levels. These winds blow at about 5 to 15 meters per second, or 18 to 54 kilometers per hour, or 11.18 to 33.55 miles per hour. So ordinary speed winds can move airborne particles even in an atmosphere that is 1/70000 as dense as Earth's at ground level, and thus should be approximately equal to about 0.000000009 the density of the planet Pluto. Of course the density of Triton's atmosphere is still over 1,000,000,000 times the density of the Pluto cloud when it expands to include Earth. Meteroids burn up and glow in Earth's atmosphere at heights of about 75 to 100 kilometers (250,000 to 330,000 feet). And I think that the atmospheric density at those levels is equal to or below that of Triton's surface. Obviously if Mars or the Moon exploded it would be far more likely to devastate Earth than if distant Pluto exploded. **PART FOUR: A SHELL INSTEAD OF A SPHERE?** But what if the expanding Pluto cloud is not a spheroid, but a shell since the contents of that shell have almost exactly the same speed outwards from the center of where Pluto was? Suppose that sometime in 2020 Pluto's former position is 5,100,000,000 Kilometers from Earth when the shell first reaches Earth. Suppose that the shell has a thickness of 1,000,000,000 kilometers. The void inside the expanding shell should be an approximate sphere with a radius of about 4,100,000,000 kilometers, while the outer surface of the expanding shell should have a radius of 5,100,000,000 kilometers. According to my rough calculations using figures of billions of kilometers and fractions of a billion kilometers for the radii, the shell would have a volume of 555.65 units if it was a sphere, the inner sphere should have a volume of 288.7 units, and the larger sphere minus the smaller sphere would have a volume of 266.95 units, the volume of the shell. So the shell would have 266.95/555.65, or 0.4804, of the volume of a sphere with a radius of 5,100,000,000 kilometers, and thus should have a density of matter that is about 2.0815 that of a spherical Pluto cloud with the same outer dimensions. What if the Pluto cloud shell has a radius of 5,100,000,00 kilometers and a thickness of 1,000,000 kilometers? Then the sphere inside the shell will have a radius of 5,099,000,000 kilometers. So the outer sphere would have a volume of 555.65 units and the inner sphere will have a volume of 555.32. Thus the volume of the shell would be 0.33 units, which will be 0.33/555.65, or 0.0005938, of the volume of a sphere with a radius of 5,100,000,000 kilometers, and thus should have a density of matter that is about 1,682.8787 that of a spherical Pluto cloud with the same outer dimensions. What if the Pluto cloud shell has a radius of 5,100,000,00 kilometers and a thickness of 1,000, kilometers? Then the sphere inside the shell will have a radius of 5,099,999,000 kilometers. So the outer sphere would have a volume of 555.6467401 units and the inner sphere will have a volume of 555.6464133. Thus the volume of the shell would be 0.0003268 units, which will be 0.0003268/555.6467401 or 0.000000588, of the volume of a sphere with a radius of 5,100,000,000 kilometers, and thus should have a density of matter that is about 1,700,680.272 times that of a spherical Pluto cloud with the same outer dimensions. What if the Pluto cloud shell has a radius of 5,100,000,00 kilometers and a thickness of 1 kilometer? Then the sphere inside the shell will have a radius of 5,099,999,999 kilometers. So the outer sphere would have a volume of 555.6467401 units and the inner sphere will have a volume of 555.6467398. Thus the volume of the shell would be 0.0000003 units, which will be 0.0000003/555.6467401 or 0.0000000005399, of the volume of a sphere with a radius of 5,100,000,000 kilometers, and thus should have a density of matter that is about 2,000,000,000 times that of a spherical Pluto cloud with the same outer dimensions. Clearly an exploding Pluto would produce a Pluto cloud that would devastate Pluto's moons. And if that Pluto cloud was an expanding shell instead of an expanding spheroid the density of matter could be great enough to devastate any comets, asteroids, etc. within millions of kilometers of Pluto's former position. It is uncertain whether that expanding shell could have enough density to seriously impact Earth when it reached Earth. The orbital speed of Pluto averages about 4.7 kilometers per second - 16,920 kilometers per hour - and the orbital speed of Earth averages about 29.8 kilometers per second - 107,280 kilometers per hour. So when particles from Pluto reach Earth, the difference in their velocities will be significant, which will increase the impact of Earth being impacted by those particles. Of course in order for Pluto to blow up and some of the fragments reach Earth the particles with have to have acquire a speed relative to their former position. That speed could be a tiny fraction of the difference between the orbital velocities of Earth and Pluto, or it could be many times the speed difference. Obviously if Mars or the Moon exploded it would be far more likely to devastate Earth than if distant Pluto exploded. **PART FIVE: A SECOND SUN?** The amount of energy required to impart to every particle of Pluto's mass sufficient speed to escape from Pluto's gravity and not recombine would be immense. It would by a small fraction of the energy needed to explode Earth or Alderaan, but probably much more than the energy needed to explode either of the hollow Death Stars. Imparting that much energy to the mass of Pluto should make that mass super hot. Which means that mass would radiate a lot of energy before it cooled off. Pluto has a radius of 1188.3 kilometers, while the Sun has a radius of 696,342 kilometers, 585.998 times as large. When the expanding Pluto Cloud swells to have the same radius as the Sun, it should still be very hot. If the Pluto cloud has the same temperature as the Sun's surface when it has the same size as the Sun, it should emit the same amount and type of radiation as the Sun. The distance of Pluto from the Sun and from Earth varies with time. Assuming that the Pluto cloud is about 39.48 Astronomical Units (AU) - an AU is the average distance between Earth and the Sun - from the Earth when it emits as much radiation as the Sun, the amount of radiation that Earth gets from the Pluto cloud will be the same as it gets from the Sun, divided by 39.48 squared (1,556.3016), or 0.0006425 as much. Assume that the Pluto cloud emits 1,556.3016 times as much radiation as the Sun does when the Pluto cloud is 39.48 AU from Earth. Then Earth will receive exactly as much radiation from the Pluto cloud as Earth gets from the Sun. If the Pluto cloud is exactly opposite to the Sun as seen from Earth, it will rise when the Sun sets and set when the Sun rises. Thus every part of Earth will have 24 hours a day of the equivalent of full sunlight. And the temperature of Earth will rise and rise and rise and mass die offs of plant and animal life will begin. If the Pluto cloud appears right beside the Sun as seen from Earth, it will rise and set with the Sun, and Earth will heat up in the day and cool off at night as usual. But it will receive twice as much radiation as it usually gets, and thus will heat up more during the day than it cools off at night. So Earth's average temperature will rise and rise and rise each day and mass die offs of plant and animal life will begin. And if the Pluto cloud is in an intermediate angle to the Sun as seen from Earth, the effects will be intermediate between the two extremes. No matter what the positions of the Sun and the Pluto cloud are when seen from Earth, if the Pluto cloud emits anything close to 1,556.3016 times the radiation of the Sun, Earth's goose will be cooked, along with all the geese. And I have no idea whether the Pluto cloud will emit only a tiny fraction of the radiation emitted by the Sun or many times the radiation emitted by the Sun. Obviously if Mars or the Moon exploded it would be far more likely to devastate Earth than if distant Pluto exploded. **PART SIX: WORMHOLE?** Of course the aliens might not simply explode Pluto to get rid of it. They might create an artificial wormhole and open one mouth of it right ahead of Pluto and its moons in their orbit. Pluto and its moons will enter the mouth of the wormhole and come out the other mouth of the wormhole in some other region of space and time. Doing so would have very little effect on Earth, although the absence of Pluto would eventually be noticed. And possibly scientific instruments might notice some effects of the artificial wormhole while it is open. So exactly how the aliens get rid of Pluto could determine whether nobody on Earth notices it for weeks or months at one extreme, or all life on Earth dies out within a few months on the other extreme. [Answer] **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. We wouldn't notice its gravity was gone, we might not even notice the bang. There's not enough of Pluto for it to have a marked gravitational effect on the Earth, according to the [tidal force](https://en.wikipedia.org/wiki/Tidal_force) calculation: $$F=\frac{2GM\_1M\_2d}{r^3}$$ Where: * $F$ is the force exerted on Earth by Pluto * $G$ is the [Gravitational Constant](https://en.wikipedia.org/wiki/Gravitational_constant) * $M\_1$ is the mass of Earth * $M\_2$ is the mass of Pluto * $d$ is the distance between them * $r$ is the radius, in this case, of Pluto Pluto exerts a mere 7.8x107N of tidal force on the Earth only 0.000000001% the average pull of the Moon. Furthermore as no-one currently has Pluto under routine observation it could be quite some time before we even realise it's gone. We'd notice if the aliens destroyed it by giving it a push into the inner system, it would be the biggest comet in our history but it would take a long time getting down here near the sun. Otherwise we might notice a slight increase in comet activity and then again we might put it down to something else, theory has it that Earth should be the victim of a large impact event in the [geologically](https://en.wikipedia.org/wiki/Geologic_time_scale) near future. As a note if the aliens use the full [2.5x1032J](https://en.wikipedia.org/wiki/Gravitational_binding_energy) that the device would need to blow Earth to bits on Pluto there's going to be an expanding ball of atoms where the planetoid was. The nebula-like effect this creates would be short-lived but we'd probably see it before the solar winds pulled it apart. [Answer] **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. Pluto’s gravity has no detectable effect on the rest of the solar system, and its absence will also have no detectable effect. The chances of a fragment striking the Earth depend on exactly how Pluto is destroyed, with the application of how much energy, breaking it into how many fragments, so you’ll need to provide those details. Specifics are addressed in physics StackExchange question '[Pluto's gravitational pull on a person on the Earth's surface?](https://physics.stackexchange.com/q/24309)' demonstrate the gravitational force exerted on the Earth by pluto (~10E-14 N) is on par with the gravitation attraction between two average adults. ]
[Question] [ Since most online and media depictions of EMPs run the gamut from devastating annihilation (complete with sparks shooting from every angle) to gentle shutdowns resulting in inconvenient repairs, what's the reality of small-scale EMPs used against military personnel in a vacuum or near-vacuum environment? Would this automatically be a death sentence for the affected troops (as well as leaving them potentially defenseless)? Would spacesuits and personal weapons like particle-wave or Gauss rifles be utterly destroyed or would redundant systems be possible in order to reboot their functionality? [Answer] Given the hostile environment in space, preparation for EMP equivalent events is a normal consideration. For example, when a massive CME hits, many satellites have to be rebooted. In short - EMP is a common enough natural event in space that it would be a temporary inconvenience to troops that they train for regularly, independent of it being weaponized. It could prove decisive in specific military actions, buying time for attacking troops to close, but in and of itself would not be a novelty. [Answer] **EMPs can be astonishingly devastating.** The EMP that was created by a test of the atomic bomb 'Starfish Prime' in the Pacific ocean blew out about 300 streetlights and disrupted telephone and radio services in *Hawaii*, nearly *1000 miles* away from the blast. Considering that power, it's possible that this technology could be implemented, albeit on a smaller scale. I'm not sure how small or powerful such a device might be, but I think it could work. Now while some minor EMPs only temporarily disrupt the functionality of electronic equipment, **more powerful, intentionally weaponized ones could easily completely overwhelm the target circuitry with high currents and would irreversibly melt/fry them.** This will *not* be fixed by a simple reboot. The vulnerable wiring in life support and coil guns would burn out without too much of a fight, and even a small failure in one area in an electronic device has a good chance of causing critical failure down the line. Your enemy space troops are quite doomed. It would seem like an EMP based device to attack enemy troops might be feasible. **However, the problem with this EMP based warfare is that it's just *so easy* to shield anything from an attack.** Surrounding the delicate circuitry with a conductive material (or a faraday cage) prevents the pulse from penetrating any further. If such a weapon was widely available, undoubtedly essential items such as the life support on space suits and probably weapons too would be shielded. The only thing that cannot be shielded would be an antenna (you *can* actually shield them from electromagnetic waves, but that would ruin the point). So in conclusion, your high-power EMP could probably knock out communications, but it isn't likely to do much more than that. Hope this helps! [Answer] **What does an EMP actually do?** An electromagnetic pulse (EMP) works the same way a generator does. The magnetic pulse moves across metal and, depending on the conditions, couples energy onto the metal in the form of electricity. Said another way, when you move a magnetic field across a wire, it causes the electrons to move. The longer the metal, the worse this is. The more conductive the metal, the worse this is. let's look at a short list of consequences and let's assume we have some zombies in front of us to deal with. * Wooden club: An EMP wouldn't effect this at all. Not even if you have nails in it. You're peachy safe, beat the snot out of those zombies! * Colt .45 revolver: if the EMP is strong enough, it'll shock you, but other than that, very little would happen to the weapon. Pick it back up and shoot the zombie in front of you. * M1 carbine: It doesn't take as much of an EMP to get shocked by a rifle due to the longer piece of metal. However, more-or-less the only thing you're touching that is metal is the trigger. Rather than forcing you to drop it, the EMP is more likely to cause the muscles in your finger to contract, firing off the round. Probably not a zombie in front of you, so you'll be using the rifle as a club until you can cycle the bolt. * Gauss rifle (aka, railgun): Gauss rifles use magnetism to accelerate a slug of some kind to breathtaking velocities. The problem is that you need coils of wire to make that happen. The coils may be small, but you have the proverbial miles and miles of wire in them — and long wires are bad when it comes to EMPs. An EMP can actually melt the magnetic coils in this sucker. So, after a good sized EMP, you have a paperweight you can throw at the nearest zombie, then you need to pull out your knife. * Particle-wave: see Gauss rifle. You're using magnetics to control energy flow. No magnetics after an EMP. * Space suit: This is more complex. The basic functions of the space suit (e.g., keeping oxygen in and the vacuum out) won't be hurt at all because most of the suit has very little metal and what is metal is (in today's tech) aluminum. Now, aluminum does conduct electricity fairly well, but it stinketh mightily when it comes to coupling energy, which is why you don't often see it used in generators. So, basic functions are OK. The computer systems controlling oxygen flow might be fried — maybe. Hollywood makes it look like everything electronic is blown by an EMP. The reality is that while all those copper traces will couple energy, they're small and the largest chunks of them are the ground-plane and power-plane — and those are connected to the power supply. Therefore, the real question is how much energy can the power supply (aka, battery) absorb and how quickly? My point is, it actually takes a pretty good sized EMP to hurt operating electronics (or even cars) and it isn't the electronics that are usually the first to go, it's the batteries and power supplies. **Yeah, but how much EMP can all those things take?** Unfortunately, that's an answer that's well outside the scope of this site because EMP size will depend on (a) the specifics of the device or piece of equipment we're talking about, (b) the surrounding geology, and (c) the nature of the device creating the EMP. (b) is important because an area that's electrically grounded well (for example, the "earth" has a negative charge) will absorb a ton of the energy from the pulse. Said another way, you need a stronger pulse over a large body of water than you do in a desert.*Citation Needed* (c) is important because EMPs are no different than any other magnetic or electrical effect. The pulse width, magnitude, and the slope of the leading and following pulse edges all contribute to how damaging the pulse is. A really narrow, very sharp, low-magnitude pulse may cause a shock but probably wouldn't seriously damage anything. A massive magnitude, very wide pulse (almost regardless of the slope of the pulse edges) will pretty much melt anything metal (if you understand integration, the amount of energy is the volume under the curve &mdash big volume = bad). However, really shallow edge slopes can mitigate a lot of harm. Think of it this way. A shallow but fast-moving wave can knock you around, but usually won't kill you. A tidal wave will sweep aside almost everything in its path. But a wave (almost regardless of how big it is) that gently builds to its peak and then gently recedes, won't damage a lot of things. (Those were imperfect metaphors, but they'll do). **So, why do people fear EMPs?** It's not the equipment that's the problem (well, remember that long wires like power lines are a huge problem), it's all the electromagnetic signals in the air that we depend on that's the problem. A good sized EMP will disrupt an entire nation's communications network because all that energy is washing around in the air. It may not damage antennae, etc., but you'll lose pretty much all forms of modern communication if you experience one. And, worst of all are *hard drives.* Indeed, all magnetic storage media is *incredibly* susceptible to EMP — and there's next to nothing you can do to stop it. You can enclose them in Faraday cages, but those cages are only as useful as they are grounded — and if the EMP is affecting the natural-earth ground plane, then your Faraday cage is worthless. You can kiss most of the nation's data goodbye. **Fine, fine, but how can I really protect myself?** You can coat things in metal and connect that metal to something that can absorb energy. Remember when I said a Gauss rifle is basically a lump of metal after an EMP? OK, coat the shell of the gun in highly conductive metal (aka, a Faraday cage) and connect that metal to the negative terminal of the weapon's power supply. Now you have the same problem as the space suit: if the power supply can absorb the energy, the weapon will continue to work (perhaps after a re-initialization, raising the voltage on the negative terminal won't hurt the weapon, but it will stop its operation until the voltage drops again). So you can protect yourself — to a degree. Honestly, your enemy is always able to build a bigger EMP, so protection is valuable, but limited. ]
[Question] [ If you could deflect most of the light off planet Mercury and to a focused point in the sky, for example, could you heat up a planet like Neptune? You could also start this process at the poles where it is a comfortable temperature for humans. Is this a crazy idea or has there been any thought around it? Enlighten me. [Answer] **No** Reflecting and focusing light requires a strict control on the geometry of the system. What you need to deflect light hitting Mercury and focus it on Neptune is an adaptive parabolic mirror with adjustable focal length in a working range of millions of kilometers. Even if that was possible, you would still have two major problems to overcome: * The Sun covering Mercury as seen from Neptune for roughly half of the time * Mercury being flimsy in comparison to Neptune (see image, courtesy of [this](https://www.universetoday.com/36649/planets-in-order-of-size/) site). Mercury is the one at the bottom right. [![Planet size comparison](https://i.stack.imgur.com/zZ759.jpg)](https://i.stack.imgur.com/zZ759.jpg) [Answer] Kind of related to your question - there have been several proposals in the past for the use of [giant space mirrors](https://en.wikipedia.org/wiki/Space_mirror_(climate_engineering)). The idea however, was to cool down the planet by blocking a portion of the incoming sunlight. One was proposed as a way to combat global warming, and the idea was also proposed to start terraforming Venus. There was also a project called [Znamya](https://en.wikipedia.org/wiki/Znamya_(satellite)) which was a Russian project using a space-based mirror. A prototype was successfully deployed - the idea was to help boost solar production on the ground by increasing the sunlight. If you wanted to warm up a planet or moon in the outer solar system, a better approach might be to park giant mirrors close to the target, to catch and concentrate more of the weak solar energy. That way you don't have to worry about further diffusion and aiming. However, a giant parabolic or slightly curved mirror might be able to focus a beam of sunlight and send it into the outer solar system without dispersing. You'd have to keep re-orientating the mirror to aim it though, as you're trying to hit a moving target. [Answer] ## No, because the tidal forces are too high. Because the planet Mercury is so close to the Sun, it experiences enormous tidal forces, about 17 times stronger than the moon's effect on the Earth. Furthermore, the planet's orbit is eccentric, so these tidal forces vary. The forces are so strong that Mercury's spin is 3:2 tidally locked to the Sun (i.e. 3 rotations about the planet's axis for every 2 orbits around the Sun). Venus and Mars lack a magnetic field because their cores cooled billions of years ago. Mercury ought to be this way, too, but it's not. Mercury's tidal forces are also strong enough to keep the planet's iron core molten and flowing, giving the planet a magnetic field. Think about this: *the tidal forces are strong enough to melt iron*. Whether your mirror is built on top of Mercury, built by the material of Mercury, or just in the same orbit of Mercury, it will experience these tidal forces. In the worst case, the tidal forces will tear apart your mirror. In the best case, they will deform the mirror so it no longer produces a collimated beam. The light from your mirror will be no more concentrated than the light directly from the Sun. [Answer] # No, because you cannot *gather* light As I wrote in [this answer](https://worldbuilding.stackexchange.com/a/67691/12297), you cannot actually *gather* light. You cannot gather light from a wide cone, and then send it out into a thin beam. Whatever the angle was that you collected light from, what you emit cannot be a more narrow angle than that, if you are using only optics (i.e. refraction and reflection). This is called [Conservation of Étendue](https://en.wikipedia.org/wiki/Etendue) and [xkcd has a better write-up of that](https://what-if.xkcd.com/145/) than I can produce. Mercury is at about 0.4 AU from the sun, while Neptune is at 30 AU. 30/0.4 = 75. This means that whatever light you reflect off of Mercury, when it reaches Neptune that light covers an area that is 75 time larger than the Sun, in effect 75 times **weaker** per unit of surface area than what hits Mercury. Also The Sun has a surface area that is about 80 000 times as large as that of Mercury, so now we are down by a factor of 6 000 000. So no... this just is not worth the effort at all. [Answer] As everyone else said, **there is no scientifically sound way to effectively reflect a sufficient amount of light from Mercury to Satur**n. But you're in luck since Russian scientists already found a solution to your problem: [Project Znamya](https://en.wikipedia.org/wiki/Znamya_(satellite)) (meaning "Banner) they constructed a 65-foot-wide sheet of mylar that could be unfurled from a central mechanism and launched from the Mir space station. They basically sent a giant mirror in orbit around Earth, in your case it would be orbiting around Saturn or its satellites. The experiment did in fact work but to have a system that could actually be used to lit up the whole planet they still had a long way ahead First of all the size of the mirror > > The plan was to first test a 65-foot mirror (Znamya 2), then a 82-foot > version (Znamya 2.5), finalize the test phase with a 230-foot mirror > (Znamya 3), and, eventually launch a permanent 656-foot space mirror > installation that would be capable of fully turning early night in > Russian cities into something close to full-blown day. > > > And then the scale of the system > > "The scheme called for a chain of many satellites to be placed in > sun-synchronized orbits at an altitude of 1700 kilometers, each one > equipped with fold-out parabolic reflectors of paper-thin material," > Crary writes. "Once fully extended to 200 meters in diameter, each > mirror satellite would have the capacity to illuminate a > ten-square-mile area on earth with a brightness nearly 100 times > greater than moonlight." > > > And we're talking about Earth. Saturn has diameter 9.5 times bigger than our planet and a surface 83 times bigger. So of course your satellites will need to be way more that what you'd use to lit up Earth and probably bigger as well. [![enter image description here](https://i.stack.imgur.com/ZVEWJ.jpg)](https://i.stack.imgur.com/ZVEWJ.jpg) For a more in depth article: [The Man Who Turned Night Into Day](https://motherboard.vice.com/en_us/article/9a3y8d/the-man-who-turned-night-into-day) [Answer] Most people already explained why this is not a good idea and why it doesn't work - mainly because: Mercury moves very fast around the sun and has a relatively small area to collect light from. For starters, we would need a place that doesn't change in relation to your planet. Enter: The five Lagrangian points, which are points where the gravity of your planet and the central star is at an equilibrium. There are 5 of them. They look like this: L1: Between your planet and the star. Not very useful since any light it collects would also be blocked. L2: Opposite side of L1, behind your planet from the star's point of view. Doesn't see a lot of light, so... meh. L3: Behind the star. You would have to reflect the light through it, so that doesn't work either. L4 and L5 are more interesting. The planet follows the L4 point and is followed by the L5 point in its orbital path. You place giant mirrors there. A nice advantage is that those are the stable lagrangian points, meaning if something drifts away from those points it'll be drawn back towards them. A disadvantage is that they often contain asteroids ("Greeks" in front of the planet on the orbital path, "Trojans" following the planets), not problematic for realistic space structures, but can possibly interact with monumentally scaled ones. ]
[Question] [ In "The Thousand and One Nights", the ghouls were vile tricksters and ravenous flesh eaters. They kidnapped victims and lured lustful men to their doom by taking the guise of beautiful women. Sometimes they even snuck into storerooms and munched on dates. The Arabic texts apparently did not identify them as grave robbers who dined on the dead. So I guess they won't turn down a living meal if the situation presents itself. A panda's diet is 99% comprised of bamboo. But bamboo doesn't have a lot of nutritional value, so pandas have to eat 26 to 83 pounds of bamboo a day. I'm not an expert on biology but does that mean ghouls need to eat a lot of humans if their digestive system can only breaks down one type of food? Pandas are from the animal order Carnivora, though, and so they occasionally will eat small rodents. I imagine this is true for ghouls too. My question is: if ghouls are able to derive nutrients from flesh other than humans, why would they prefer to hunt and feed exclusively on humans? From my point of view, the ghouls risk being exposed if a lot of humans go missing. [Answer] [Prions](https://en.wikipedia.org/wiki/Prion) It's known that there are [certain diseases](https://en.wikipedia.org/wiki/Kuru_(disease)) that are caused by prions (misfolded proteins, **largely specific to the species**) and target the same species. (Some, such as [BSE, a.k.a. "Mad Cow Disease"](https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopathy) *can* affect other species though) When a ghoul eats a human, the prions, instead of causing illness, are used like a catalyst or vitamin - they are necessary for the ghoul to remain healthy, instead of turning into a shambling corpse. (Think [scurvy](https://en.wikipedia.org/wiki/Scurvy), [Vitamin D deficiency](https://en.wikipedia.org/wiki/Vitamin_D_deficiency), [pernicious anemia](https://en.wikipedia.org/wiki/Vitamin_B12_deficiency_anemia), or even [diabetes](https://en.wikipedia.org/wiki/Diabetes_mellitus)) (Also, prions are often found in high concentrations in the brain, so the answer also applies to zombies) [Answer] Humans are currently one of the most numerous large animals on Earth, and furthermore tend to concentrate in dense groups. For a creature that lives in cities and is *able* to kill humans easily, effectively and without significant danger of retaliation, humans will be the best source of meat. This would not have been a viable niche in prehistoric times, but it is now. People go missing all the time, especially in big cities. Maybe in the far future, in a dystopian setting where population is high, food is scarce, and the value of individual lives are low, a subgroup of urban humans might adopt cannibalism as a major source of nutrition and evolve into a new species, growing better at snatching people off the street. Or perhaps they have been living alongside us in secret, having split off sometime since the growth of civilization. [Answer] If a species is eating one specific type of food, their digestive systems have evolved to become adapted to extract the most nourishment from it and to be resistant to eventual poisons. This also likely causes their tasting buds to "like" that type of food, thus driving them instinctively towards the food they are best adapted to. One distinctive feature might be the nourishment human brains yield to them. Plus they have the skill sets required, as described in the question, to hunt for humans, so why should they forsake their nature to go against it? **Morality** could be a reason, however [Nietzsche may disagree](https://philosophynow.org/issues/70/Nietzsche_and_Morality): > > He tells us that “man needs to supplement reality by an ideal world of > his own creation.” That is, we are compelled by our biological natures > to see the world through moral lenses, judging it in terms of good and > bad, although the world is neither in itself. > > > Which could mean that ghouls would not see killing and eating humans as amoral, just as we don't see much amorality in eating cattle even though we could resort to eat stuff which is already dead or about to die like fallen fruit or animal corpses. Why should ghouls eat things which are less nutritious and tasty to them, which may be the things allowing them to reach their peak healthiness? Another factor could be **danger**. However, that's something all species have to deal with anyway, especially carnivores. What if they are better off if continuing to take that risk, because doing what humans do simply does not cut it [well enough](https://ourworldindata.org/extreme-poverty) (at least not up to ~2 centuries ago), or if they are intellectually-culturally unable to even consider that? It's not like humans consistently enact the [most moral](https://en.wikipedia.org/wiki/Mass_killings_under_communist_regimes) and [best systems](http://www.businessdictionary.com/definition/coercive-power.html) imaginable, so why would you expect them to step over their shadows in such regards - even *if* they are capable of thinking as humans? There are plenty of arguments against this notion, but relations based on violence and coercion (parasitic or exploitative) usually do not argue in [fair terms](https://en.wikipedia.org/wiki/Indoctrination), nor do they benefit from doing so. The predator will always seek for things that makes [his life easier](https://en.wikipedia.org/wiki/Slavery), or whatever is [needed to adapt](https://en.wikipedia.org/wiki/Democracy). It is likely it will never even come to that consideration. I may have a, let's say, dark undertone in this, but I guess you are good to go with ghouls preying only on humans, not only on a biological standpoint, but also on social, moral and intercultural. Maybe it can assist as fuel for explanation from the side of ghouls. [Answer] ### Humans are yummy They prefer the taste of human flesh over the flesh of rodents that crawl around everywhere. Especially when munching on humans that are well off and can therefore afford to be clean(er) most of the time compared with other animals. That would also explain certain preferences when it comes to humans - the more well off someone is, the higher the chance that they will be eaten. The strategy to disguise as women to find some men would also fit when those men were rich and therefore cleaner, making them more yummy. More work for more tasty food. The same could of course be said about dining on female humans, but maybe it's just easier to lure men into their doom and they don't really distinguish between male and female humans - humans are all tasty. In a dire situation where the ghouls have to fight for their survival or it's too risky to feed any more on humans they might try to feed on something else, but they simply prefer the taste of human flesh. [Answer] Ghouls are traditionally a supernatural species, their lust for human flesh is, in large part at least, tied to this. In order to survive they need to consume not only food but also "life essence" for want of a better term. Normal foods have very little essence so they can sustain a ghoul physically for a time but they don't work for long. Humans aren't the most physically pleasant or nourishing food but they have essence to spare, the fresher the better. Only a steady diet of human flesh can actually satisfy a ghoul's complete food needs. [Answer] 1. Meat is energy dense and very digestible. Bamboo is neither. If all you eat is one kind of meat, that is fine. There is not really an analogy between the diets of ghouls and pandas. 2. Hunting is dangerous; hunting humans is dangerous for sure. Eating dead things you find is much less dangerous. In places where there is a high population density of humans there will be a steady supply of people who have died of natural causes. You might need to dig up the meat if people bury their dead. In places where dead bodies are put in rivers or undergo "sky burial" it would be easier for scavengers - which is likely the fate of the corpses disposed of in these ways. The analogy is the jackal. Jackals occur from Africa thru the middle east to India and are probably the origin of ghouls - I bet a jackal would be thrilled to eat a bunch of dates too. Jackals will definitely dig up a grave and eat the contents. They are tricky and wily like foxes. But jackals do not hunt humans because they are little and weak and would get their jackally asses kicked. I might imagine that a moribund human might be helped with his transition by an especially brave jackal but more likely it would just sit and wait things out. So too ghouls. ]
[Question] [ Going through labour is an intense and painful process that can last anywhere from 8 to 18 hours. It was also very dangerous for women during the middle ages. The lack of medicine and healthcare led to many unnecessary deaths during childbirth, with numbers varying depending on location and family wealth. Fortunately, witchcraft is a respected field in this alternate history, and witchery is seen as a respectable trade among the population. A field of magic called Biomancy has been recently invented which is hoped will revolutionize medicine. Biomancy is a form of magic that allows for the manipulation of certain biological energies and processes. Through this art, biomancers are capable of changing or influencing a change in the physical form of either themselves or others to limited extents. It allows for a number of things: 1. Cellular Control - Granting immunity to poison and extreme temperatures. 2. Regeneration - Healing injuries, regrowing parts over time, strengthening durability, and removing of fatigue. 3. Fleshsculpting - Manipulating or shaping the body to limited extents. Midwives take the form of witches who specialize in childbirth-focused Biomancy magic. How can I use this form of magic to make labour less difficult and risky? At what point would it be most appropriate to apply these techniques? [Answer] I would like to divert the actual question a bit, but, If the real motive behind this is to actually ease the mother from the pain of childbirth. Then I would rather suggest that it would be better to remove the embryo itself from the womb and let it develop in an artificial environment. The process could take place something like this: 1. First, simply detect that the woman is pregnant. 2. Wait till the embryo is stable in the womb (maybe 2-3 months) 3. Use the "Cellular Control" to extract the now stable embryo from the womb. 4. Use the "Fleshsculpting" to create an artificial womb chamber. 5. Let the embryo develop within this chamber. 6. Use the "Regeneration" to help the mother recover. This procedure has certain added advantages, like: 1. There will be no pain for mother. 2. Mother will be free to do the routine tasks after an initial time of 3 months. 3. The rate of accidental miscarriage will become low. 4. The baby can result in a better health as the chamber will be well fed with proper nutritious supply. 5. Also, you can control certain traits in this chamber e.g.making baby immune to common diseases, controlling any unwanted mutations, etc. Now, I am not sure if I can use mythology as a proof of concept here. But, In Hindu Mythology, in Mahabharat: Once, Queen Gandhari asked to have a boon of 100 sons. Humanly it was not possible so the above-said procedure was actually used to grant her wish of 100 sons and 1 daughter as an added bonus. [Answer] If you're able to safely shape the body to even a limited extent with your magic (point 3, you mention sculpting the body), you could probably widen the birth canal to some degree. It wouldn't take much to make it easier for the mother's body to push the baby out, and feet-first births would probably no longer be a medical emergency. If time spent in labor can be reduced to a couple of hours (instead of 10+), that's obviously more pleasant for the mother. You would, of course, have to restore the birth canal to its normal size afterwards, since widening it probably would have an effect on the hips and impair the ability to walk upright; that would for obvious reasons be problematic. Your second point suggests conventional healing magic (closing wounds). This has some obvious applications for dealing with torn flesh during childbirth, allowing the mother to be back on her feet sooner; you'd also be able to counter the risk of the mother bleeding to death. In the event that a C-section is necessary despite all that your magic can do, this would give the mother a decent shot at survival (I'm not sure when this changed, but historically that operation was certain death for the mother), and again would also help her recover much faster. If your healing magic also deals with infections, that right there eliminates a lot of post-birth complications that can potentially kill the mother, so you've made it significantly safer for her. Ultimately, though, most historical deaths in childbirth were the result of infections contracted while in labor that led to fatal complications. Most of these infections came from filth, especially dirty hands. So your single greatest help won't be from magic at all: just make sure your midwives know that cleanliness and sanitation are vitally important for good health. [Answer] Several magical disciplines can produce effects similar to modern medical assistance. * Divination and prophecy can serve in place of an pre-delivery ultrasound. * Blood magic is probably more accurate than an a modern paternity test, with curses available to discourage paternal negligence.+ * Sleep, Hypnosis, Enchantments, and Mental-Enslavement spells as well as my custom Hero Chant (which causes immunity to all physical pain) are all good substitutions for sedation and pain killers. * Wards and protection spells can banish bacteria from an area, providing a sterile field. * Just whatever you do, don't let the expectant mother near a Wish spell... or fathers will learn exactly how painful child birth can be! [Answer] Such magic would finally make the centrifugal birth machine feasible! [US patent US3216423A](https://patents.google.com/patent/US3216423) describes a machine that uses a rotating bed to expose the baby to forces up to eight times that of the gravity of the Earth, in order to facilitate their exit from the womb. It looks like this: ![Centrifugue assisted birth](https://i.stack.imgur.com/QH9f3.png) You may now be thinking that this would cause the child to shoot out of the mother's belly like a bat out of hell. The inventors thought of that too; Notice the net between the mother's legs. It is there in order to catch the baby. Now let's add magic. The idea is that a mechanomancer would use their magic to activate such a table (such magic is required because your world has dark age technology). If that was the whole of it, it would be quite traumatic to the mother and child, but hey, you can't make an omelet without a few broken bones. But this is where the biomancers take their cue. The biomancers would use cellular control to make both mother and child's cells more full of water and fat. Water will add resistance to high G forces, and fat will protect against impact. Flesh sculpting may widen the cervix, so that no C-section (it already existed in the dark ages) is needed - it would be impossible to perform in a gravity more than twice as strong as Jupiter's anyway. Flesh sculpting may also make the baby round as a ball so that the impact of birth is more evenly distributed throughout their body. Finally, flesh sculpting is reversed and any damage dealt is reversed with regeneration. The application of thinkamancy spells such as *forget bad experience* on the mother and child and *let's never talk about this* on the family members watching the staff do their magic is recommended to avoid long lasting mental trauma. And that's it! Welcome to the world, child! [Answer] In general, Biomancy won't help medicine much during this time period without some extra knowledge. As Palarran mentions, "Medical" knowledge wasn't that great until, realistically, late 1800s or early 1900s. Up until that general era, people didn't know about things like bacteria or viruses or even keeping things sterile and clean was super useful. Bloodletting was a common practice - It was used in an attempt to help George Washington, in December of 1799. If people still think these practices are the "Correct" method, they'll still focus on them and still use them, and won't do things like boil the surgical instruments or other things that were possible but never thought about. Realistically, the practical uses of Biomancy, in relation to pregnancies, are pretty small. Reducing pain makes childbirth less unpleasant. Changing the body to temporarily enlarge the birth canal might allow some births to go smoother. More rapid healing might help people survive C-sections - but as I mentioned in the comment to Palarran's answer, C-sections were generally used as a last resort. What is *truly* needed is for Biomancy to somehow guide witches to modern and semi-modern medical ideas that can still be implemented. Keeping things clean, different types of suturing, that some of the practices in use weren't actually helpful, use clean water, etc. ]
[Question] [ I want to build a city in the desert outback. It needs drinkable water for its citizens, what's a few different ways to get it? (pipes from coastal areas, desalination of salt lakes, etc) What are some different ways to do this and which is the most effective and why? **Notes:** This will be built in the future with effective fusion power available. [Answer] Australia actually has the largest single Artesian Basin in the world right underneath the outback. The [Great Artesian Basin](https://en.wikipedia.org/wiki/Great_Artesian_Basin) was what allowed Europeans to rapidly expand across the country - water would push up from the ground anywhere you dug a hole. The major problem isn't whether there's water, it's making sure your water supply replenishes rapidly enough to be sustainable. For the GAB, it's basically a mining operation, with water flowing in and through the sandstone at a rate of 1-5 meters per year. This means that your "end product" is several thousand years old by the time it reaches you - definitely not sustainable. In fact, there are already concerns about the current rate of water removal in the basin, which is why the Great Artesian Basin Coordinating Committee (GABCC) attempts to coordinate across state lines to ensure sound practices. So how do we solve the water flow problem? Pipelining or shipping water requires overland travel through the outback, which is coupled with all sorts of infrastructure requirements. Why not coordinate a country-wide effort to basically bore under the water table? The basin is estimated to be 3000 meters deep at it's deepest. That sets our "entry altitude." If we bore a series of small holes inland toward the outback that deep under water, you're basically enhancing the existing natural process anyhow. Though in densely populated areas you might have people complaining "Not In My Back Yard" (NIMBY), that's not really an issue for the sparsely populated areas we're dealing with. Best of all, if our "pipeline" leaks, that's perfectly ok - we WANT that to happen! Obstructions aren't really an issue for us - the mere existence of a hole that sea water can intrude farther and faster into the water table is all we need. An array of these holes should aid in fixing the water-supply issues all along their route. Ocean pressure two miles down is pretty significant. Far greater than the atmospheric pressure of the artesian basin, in fact. [From this article](http://web.mit.edu/HARVEY-LAB/Publications_files/Seasonal_SGD_%26_Supplement.PDF), costal aquifers regularly interface with the ocean, and the major concern is elevation differences between the two. > > In most coastal aquifers, freshwater discharge occurs year round > because the water table remains above sea level. In such aquifers, the well-known Ghyben-Herzberg approximation predicts that the depth to the freshwater/saltwater interface below mean sea level is 40 times the water table elevation above sea level, a factor that results from the density difference between saltwater and freshwater. > > > Since our aquifer surface (i.e., water table) is actually BELOW sea level, the amplification factor they mention works in our favor as sea water pushes into the aquifer to equalize levels. Or you could just wait for the sea levels to rise, so the outback becomes "infront." [Answer] [![enter image description here](https://i.stack.imgur.com/6ckr3.png)](https://i.stack.imgur.com/6ckr3.png) Australia has the benefit of being at low elevation. This would allow a largely **gravity-fed desalination** scheme. One would excavate and concrete in an underground reservoir at your population center. This should be below sea level. Given that much of the outback is at 100 m elevation or less this will be easier than would be the case in other inland sites. One might even start with a dry lakebed that is already below sea level. You will see Spencer Gulf at the south of Australia; Port Augusta is at the tip. Build a pipeline from the ocean there to your inlands low elevation reservoir. It will act as a siphon and water will flow of its own accord. Don't open it up yet! Your don't want salt water. Now: install reverse osmosis filters on the ocean side. If the pressure differential is big enough (and it is, because before digging your catchment you have factored in resistance from the pipe) the water will desalinate itself before entering the pipe. Brine is left in the ocean. Hopefully currents are such in Spencer Gulf to wash the brine away. If not you might need to place the pipe entrance out to sea a ways. Filters foul eventually and you will need to maintain the ocean side. There should be no energy inputs required to make the water flow. There should be no energy inputs to desalinate the water, gravitational potential energy doing this for you at a site where brine disposal is easy (open ocean). Your inland residents will need to pump the water up from their tank when they need it. Windmills or solar will be fine for that. Water reclamation should happen as with other inland arid regions, the reclaimed water either treated back to drinkability or used for irrigation / landscaping. [Answer] There have been plans to flood [Lake Eyre](https://en.wikipedia.org/wiki/Lake_Eyre) over the years. Bring one such plan to fruition, the earlier the better. This would have the theoretical benefit of using gravity to move the water and not pumps. Hydro power from the canal or pipes, and/or solar power to provide an energy source for desalination of seawater. Perhaps you could also use solar updraft towers as a way to generate energy and provide small-scale agriculture, maybe supplemented by treated wastewater as a means of improving water efficiency. The city could also have a small salt industry as a way of dealing with desalination leftovers. [Answer] Since the idea is to increase the amount of available water for habitation, we don't just want to supply the city, but the entire microclimate in order to support agriculture, lower the temperature and make the region more habitable. So what we want to do is increase the amount of rainfall the region receives. This can be done by building giant hollow towers along the Australian coast. Solar heat causes the air inside to rapidly rise, which can be used to power wind turbines. but the main effect is to draw humid sea level air and eject it high int the atmosphere where it will form clouds. [![enter image description here](https://i.stack.imgur.com/xHUez.jpg)](https://i.stack.imgur.com/xHUez.jpg) *Prevailing winds in Australia* [![enter image description here](https://i.stack.imgur.com/QLRmP.png)](https://i.stack.imgur.com/QLRmP.png) *Solar updraft tower* The the increase in rain will also start filling the dry lake beds and recharging the local aquifers. so this is long term terraforming for Australia, and can have benefits for the rest of the continent as well. [Answer] I'd like to add my own answer, Since fusion power would be eventually effective, We could pump sea water from the ocean, desalinating it, and filtering out heavy water for fusion. The remaining normal water would be given to the cities, while fusion provides the power for desalination. [Answer] I would ask - why build a city in the desert? No real reason to do that, unless maybe they were mining some particularly valuable substance. No food and no water in a desert, and it's going to cost an arm and a leg to arrange a steady suppy of both. It's like that old Sam Kinnison line about people starving in African deserts. Don't send them food, send them luggage and bus tickets. Move to where there is food. Having said that, there is one other way to get lots of water to a city in the desert. Since this is your world, you can arrange for a climate change that would increase rainfall substantially. Of course, if you do that, the desert would no longer be a desert. There are ancient cities in the jungles of central America and Thailand. Why are those cities located in a dense jungle? The answer is - those areas weren't jungles when the cities were built. The climate changed to result in substantially higher rainfall and higher temperatures to support jungle growth. [Answer] Well, what is water? One Oxygen and two Hydrogen atoms? The former is quite vital for life and and a bigger concern if it were to run out (the 3 laws of survival: 3 minutes without oxygen, 3 days without water, 3 weeks without food). The later is quite literally the most common substance in the universe... you can't throw a stone without hitting something that has hydrogen contained within it... including the atmosphere. This brings to mind an old "old man" joke I heard where the old man complains "Kids today have it too easy. Back in my day, we didn't have a water faucet. If you wanted a nice cool drink of water on a hot summer day, you had to smash those hydrogen and oxygen atoms together yourself. Built character it did." It's a fun joke, but its just that simple. You have the ingredients... you don't need to lay miles of pipe or have regular trucked in supplies of water... take some of that hydrogen that's lying around, scoop up some of that oxygen you aren't using to breath... mix in a nice big room at a rate of one oxygen to two hydrogen... at a little spark from your fusion power to the mix... keep that explosion contained, and cool to below boiling temperature... and there is your very own home made water. And if your citizens want more, well, just switch your green engines from chargeable batteries (Austrailians consider the range of a battery powered car "walking distance" anyway... not really... but ask an Aussie just how far "a little bit down the road translates into miles/km" and realize why the battery car isn't catching on much there) to a hydrogen fuel cell... and then collect the vehicles exhaust.. aka... fresh pure water. Hope you enjoy this entry from *Mastering the Art of Chemical Cooking. Bon Appetite* ]
[Question] [ In my fictional world, magic is rampant. One branch of magic focuses specifically on creating artificial life based on the blueprints of extant beings. Though it may be 'artificial', even a team of medically trained professionals could not tell the difference between a naturally birthed creature (any creature) and a magically concocted one. All you need is the instructions, the magical components ('ingredients' you collect from killing beings), and sufficient training and attunement to this branch of magic. **My question is this: what does this do to the perceived *value of life*?** I'm not asking about the greedy sorts that would do anything for a buck. Nor am I asking about the pacifist types that think every bear and treant just needs a hug. I mean the average Joe. If you learn that killing can bring about life (not to mention the meat, the pelts, the alchemical ingredients, and the obvious income that comes from all of this), is killing viewed the way we view it today? Edit: The only limitation is that you cannot imbue them with personalities or memories. So you aren't 'bringing people back from the dead', you are creating new life from scratch. When a being is created, they are 'born'. So a cat created would be a day old kitten, a dog created would be a day old puppy, etc. The natural instincts are the same, the learning curves are the same, the 'preprogrammed' reactions are all identical, as if they were just birthed naturally. Let me give a few examples of why I believe life would be less valued. A woman is declared barren (she cannot get pregnant, or cannot bring a pregnancy to term and therefore live birth). Her husband comforts her by going to a local mage and crafting a child for them to raise as their own. A man kills his neighbours child (accident or not, it's irrelevant). The case is brought to a judge, and the man offers to have a new child crafted to replace the child already lost. A goat farmer is getting sick and tired of that wolf pack always attacking his herd. So he takes the ingredients from the leftover goats to the mage and has him create a pack of guard dogs he can raise. He teaches the dogs to fight off anything that comes near his goats, other than the farmer, of course. Is life valued as it was? Or is a life worth only the ingredients needed to create a new one? [Answer] > > All you need is the instructions, the magical components ('ingredients' you collect from killing beings), and sufficient training and attunement to this branch of magic. > > > I am quoting this because this implies that more than one thing has to die in order to "create" new life. It really depends on what those things are that have to die. If people must die to "create" new people, then naturally, life is valued. And in this situation: > > A man kills his neighbours child (accident or no, it's irrelevant). > The case is brought to a judge, and the man offers to have a new child > crafted to replace the child already lost. > > > Just wondering how many children have to die in order to do this...the cost becomes too great--can pigs die instead? If we are talking value, you may have to lay out exactly what the exchange rate is on a goat vs a person... > > If you learn that killing can bring about life (not to mention the meat, the pelts, the alchemical ingredients, and the obvious income that comes from all of this), is killing viewed the way we view it today? > > > First there doesn't seem to be a 1=1 equivalent. That is, it doesn't sound as though you can create a baby human from 1 dead human. Second, you underestimate the cost of a newborn, the resources it takes to raise one, and the time, almost regardless of the species. Your question is all encompassing, but I believe I have answered for every species, really for example--if a horse dies and you get a baby horse, you gotta wait years for the colt to grow up--in the meantime, you gotta feed it for two years before it can take to harness and pull the same load. Third consider the power of experience and the accumulated knowledge gained over a lifetime. You ask whether this would make life worthless, but you aren't considering a person's value as an individual because of what they have LEARNED over a lifetime. That's not something a newborn can replace. I mean, think about your mother, father, husband, wife or significant other-- someone in your life that's important to you. How would you feel if they were killed and then someone handed you a baby and said "here's a replacement!" Not going to work. Because it's not the same thing. Mainly because, as you say > > you cannot imbue them with personalities or memories. So you aren't 'bringing people back from the dead', you are creating new life from scratch. > > > Lastly, life is not cheap for one more reason: all the steps needed in order to do it. You say: > > All you need is the instructions, the magical components ('ingredients' you collect from killing beings), and sufficient training and attunement to this branch of magic. > > > I would think that anyone with the instructions is unlikely to spread them far and wide. The power over life--that's a serious thing that people will pay dear for. And even if not, it could create an imbalance in nature (ie. people would kill entire species just to get the life force needed) and I am certain an organization would spring up to regulate this practice. Second you have to be trained--and I assume that takes years. If it does, it will be just like any other specialized field that takes a long session of schooling (lawyers and doctors don't come cheap because they have to pay back all those student loans...) Third, you imply that not only to you need the instructions & training, you also must have an affinity for this type of magic, which further narrows the pool of people who can do this. Unless attunement is an actual process rather than what I am taking it to mean--which is that the person is naturally attuned to the type of magic. I believe that it would be a strange world, yes, but the life of a human would not have no value, or even less value in this case. [Answer] (Note: This answer primarily argues about human lives. I'm leaving off arguments for non-sapient or less-sapient beings, because that's a massive can of worms, worth at least a two-book deal and long-term fame/infamy in ethics.) As pointed out in another answer, each life would still be valuable due to the resources spent in the raising of said being. So the value of the individual life does not change much, because the born being will still be unique, as far as their "blueprint" prepared them to deal with things as they grow and learn. One potential application in which the value of lives would change is in the application as weapons or resources. For example, if an entity has shown exceptional physical characteristics that are somewhat independent of his nutrturing (ex. builds up muscle mass more easily than his peers), then this entity's "blueprint" becomes valuable for anyone who wants muscle power as a resource. Of course, this value is not realized instantly, but suits long-term goals. As an example: using the blueprints of particularly talented individuals, militaristic states will set up cloning and training programs to make an army of soldiers that are stronger / faster / use psionics / what have you. These states cannot rely on cloning magic to answer an immediate need because the clones will still need to be raised and trained, but over decades and even centuries, such kingdoms could become more powerful. In this way, an individual's life could become more valuable if they possessed some sort of natural talent -- or more precisely, their blueprint becomes more valuable than your average-Joe-blueprint. This is because, despite nurture being a defining process for all beings, instances created using this blueprint may be more likely to possess certain desirable traits that can be made to manifest through regimented nurturing processes. Think of how breeders value champion dogs or horses. However, the value of the lives of the individuals born as part of the weaponization process may be worth less than the original because they may not manifest all the desirable traits of the original, or manifest undesirable traits, and so on. Maybe the original was patriotic due to his upbringing, but actually had an inherent trait of distrust towards authority (that was overpowered by a life of excellent mentors [cue biographical montage]). But the same cannot be said of a regiment of these clones, who can not experience life as he did; as a result, you could end up with a squad of anti-establishmentarian strongmen who trust each other (due to similarities in appearance and thinking) much more than their administrators -- sounds more like a liability than an asset. But then again, this discounts the possibility that a clone would become more valuable than the original due to a difference in their life that improved the manifestation of some desirable trait. For example, the original was strong and loyal, but was somewhat slow on his feet due to a childhood injury. A clone could be similarly strong, loyal if taught in a manner that suits his proclivities, and fast because they never had that accident. Which brings us to what? Blueprints do not guarantee that traits will manifest, especially those that require some non-mechanical nurturing component. Each clone still needs resources, and some possibly inscrutable nurturing processes to manifest traits. Your world takes away value from guaranteed physical traits, and shifts the value towards the nurturing component, as far as sapient clones are concerned. In a way, an individual's life becomes more valuable, because without a way to completely reproduce the life-history of the original, each clone will be different from the original, and even potentially greater than the original. If you cannot guarantee that a clone will behave as the original, then the clone is essentially a different person. If that clone is a different person, then the value of their life can only be judged by that which we afford all other people. As such, they may be better or worse than others from some absolute perspective (if there is such a thing), but we would be judging them like we judge all other people. In a way, the life of each sapient becomes more valuable because the world realizes that it is not the physical body that defines the value of life, but the unique life-history of that body and the consciousness that drives it. [Answer] The value of life would hardly change at all, though the concept of an endangered species would shift. Right now there's a lot of debate over the value at the start of a life (in particular, the life of an unborn child). However, when you really get down to brass tacks, that argument makes up an utterly tiny fraction of the discussion of the value of a life. What has magic removed? For women with a child, it's removed 9 months plus a few hours of agony. That's not much when compared with the 18 years that mother (and hopefully father) is going to put into raising the child. For animals, the magic of birth is pretty much gone for most people anyway. Most people who want a cat or a dog go to the store where baby animals have magically been created for them. Few actually go out and find animals to mate when they want one. The farm industry, producer of meat, has long since taken the magic out of birth. For them, this would be nothing more than one more way to make a profit, assuming it's cheaper than birthing the animals in the usual fashion. There are a few places which might change. The first is endangered animals. Right now, as far as modern science is concerned, the "magical components" are all in the DNA. This magic would open up another option. In particular, I can see this having a massive effect on the Panda industry. Pandas are notoriously difficult to mate in captivity, so the ability to create one would be incredibly valuable. The other place that could change is vegetarianism or veganism, but I have a feeling that they would not change. Most of the arguments I hear for those lifestyles have nothing to do with whether the creature is birthed. It's either about the pain it goes through being harvested, or its about the resources it consumed during its life, or any other facet of life besides being born. There might be an interesting little side track to consider regarding gender. Historically it's been said that females could survive without males, for all they would really need is their sperm. With your magic, it may also be true that males could survive without females. That could upset the balance between the genders, though in what way is probably the subject of a book, not a StackExchange answer. [Answer] My thought is that it has less negative impact on the value of life than positive impact on the value of corpses. (Presuming that the ingredients are just flesh, and don't have to be sacrificed for the specific purpose of your I'm gonna call it clonomancy. That being said, you'd probably see animals traded in for fresh versions as soon as they were no longer helpful. Or, if it's a weight-based flesh exchange, you could slaughter old adult animals to create several babies. For humans, I think you'd see a different expectation for what happens to the body. I don't necessarily see more people being killed for their ingredients, but I do see it becoming an expectation that burning or burying those ingredients is a waste. Although, it seems like there could be a path to devaluing life from there. Any society has the potential to devalue the old and permanently infirm, this society could argue that they're better remade as spare parts for new humans. And orphans could be 'recycled' so parents could have a child they 'made.' And building off of that, depending on how predictable the process is and how much it costs, parents could swap through kids a few times before being satisfied. When parents give birth, there'a all sorts of hormones kicking in to make them love the child. In this method, they don't happen. So yeah, I totally see a path to what you're looking for, but I do think it starts by increasing the value of the body until it's worth more than the life of the being inside it. ]
[Question] [ A common trope in zombie mediums in to base the virus off of rabies. While this choice does have some obvious reasoning to it, it has been long over done. Relatively recently, [The Last of Us](https://en.wikipedia.org/wiki/The_Last_of_Us) came out and broke away from this by basing their virus off of chordyceps, more commonly called the ant zombie fungus. This worked really well, with every step of the infected design process, clickers to airborne spores, to be based off of the original fungus. What about a [Cholera based](https://worldbuilding.stackexchange.com/a/42445/11049) zombie Infection? Similar to how a Chordyceps base introduced Clickers and Spores, what notable features would be brought along by a Cholera base? [Answer] Cholera spreads mostly through poor sanitation, contaminated by faeces. To make this a truly terrible thing in terms of zombies, your zombies are going to have to eat and excrete a heck of a lot and not be terribly well house-trained. They'll basically be stinking, shuffling, diarrhoea dribbling zombies of the worst possible kind. This will be spread by any kind of water supplies or food. Survivors are going to have to purify all their water as well as fight off the unwashed hordes (preferably wearing hypo-allergenic non-latex surgical gloves). It's what smell-o-vision was invented for. [Answer] This premise offers an excellent chance to explore a transmission route that has never been done in zombie literature. Typical cholera is spread by fecal contamination of the water but direct contact with feces works even better. Thus these zombies, instead of trying to bite like rabid skunks would explosively defecate upon their victims. Which is also sort of skunklike when you think about it. Cholera zombies would wear no pants, of course; pants greatly decrease the range attainable with an explosive defecation. Short skirts are always ok. I am not sure if they should run at the victim and at the last minute whip around 180 degrees and bend over, or if running backwards at the victim would be more effective. Some zombies might assume the lithotomy position and be carried and braced by their comrades (zombrades?) like a cholera bazooka. And there is the old monkey "flung dung" standby. Yes: a welcome reprieve from all the biting. One good thing about the biting is that you can use teeth over and over. But explosive defecation requires matter to defecate. If the zombies do not ingest this matter they will become smaller and smaller as time progresses which itself offers interesting story options. The protagonist might deal with a crowd of diminutive zombies with effective kicks, or possibly a hockey stick. Zombies could ingest victims but (a dilemma with all zombie scenarios) victims slow enough to catch are probably already zombies themselves. But is this bad? Zombies eating other zombies has not been done either and would be perfect for this. Especially if there are little tasty morsel zombies running about. A zombie replete with zombie meat will grow; not in height but certainly in abdominal girth. These very rotund short skirt-wearing zombies will generate huge internal pressures (via fermentation, as is also true for nonzombies) and be a terrifying force for contagion. [Answer] Cholera is not virus but bacteria. The main problem (from scientific viewpoint) with zombies is, that they would need energy to move, but they can't have, since they are dead, and their metabolic processes are not working. In the Last of Us, the infected people are not dead, the fungus is controlling them while they are alive. This solves the energy problem, but these are not real undead. If we forget this problem, the main feature of cholera-zombi-disease would be their waterborne nature. They would not bite. Instead, they would crowding by water sources, drinking the clean water, and then shit and vomit into it. If you would drink from the water, you would become a zombie to. Since cholera doesn't show any inclination to deal with nerve system, I don't really see, why you have picked this disease from all the water-based illnesses. ]
[Question] [ Since I cannot accept magic without redefining the laws of the universe around it, I use "sufficiently advanced technology" as a substitute. I have given much thought to [Sanderson's laws](http://coppermind.net/wiki/Sanderson%27s_Laws_of_Magic) and [Clarke's laws](https://en.wikipedia.org/wiki/Clarke's_three_laws). Where Sanderson's laws and Clarke's third law intersect is where problems arise. Technology trumps magic in every one of Sanderson's laws. * First law: We understand how technology works and can use it to solve every problem like we already do. * Second law: Technological limitations are much easier to manage than any arbitrary magical limitations. * Third law: Extrapolation leads to settings like [Alpha Centauri](http://tvtropes.org/pmwiki/pmwiki.php/VideoGame/SidMeiersAlphaCentauri), [Eclipse Phase](http://tvtropes.org/pmwiki/pmwiki.php/TabletopGame/EclipsePhase), and [Transhuman Space](http://tvtropes.org/pmwiki/pmwiki.php/TabletopGame/TranshumanSpace). [Answer] We actually don't understand technology as well as we think we do. Well, as a society we might, but the average reader actually just barely grasps the tiniest bit of it. Extrapolate further into the future to approach Clarke's "Sufficiently advanced technology," and it gets even harder. What we actually have, as a society, is great faith in technology. We're willing to just trust that technology does what the scientists and engineers say it does. This can be effective for simpler things, but as you approach Clarke's sufficiently advanced technology, it helps less and less. Take, for example, the iPhone. I can guarantee you that you don't truly understand how it works. Nobody does. Too many people were involved in that project. Some understand some small parts of it. Many understand a higher level view of it, but nobody really understands it as a whole. Let's go smaller. On a single chip in the iPhone, there are millions of transistors. Transistors are basically 2 diodes smooshed together (handwaving a ton!). Diodes permit current to travel one direction, and not the other. Great, I just explained enough technology to use diodes in a story. What if I put too much "reverse" voltage on it? In electrical engineering, we call the resulting behavior "avalanche breakdown." It's an otherwise unexpected and very sudden increase in current going through the diode the wrong way (the direction current shouldn't be able to go). You can accept this on faith, as most do. Or we can go into *why* a diode works, and cover the quantum mechanical reasons for avalanche breakdown. They're really fascinating topics, but unless you have some background in the topic, you really just have to trust me when I say they work that way. *And if your technological story ever resolves a crisis by 'reversing the polarity,' this is the kind of real life effects you would have to consider!* Let's go even simpler: solder traces. Solder is a low-melting point metal which is used to connect chips to circuit boards. In my story, the villain had amassed an unstoppable arsenal of doomsday weapons. At the darkest hour, the villain hits the button, but nothing happens. Deep inside each weapon, the hero had catalyzed metallic crystals to form, creating short circuits. Sound fantastical? In 2003 it would have sounded like a movie plot. Then the EU passed RoHS, an act of legislation preventing the use of hazardous materials such as lead in electrical components. Solder was partially made of lead in those days, so they had to change its composition. Unfortunately, the new composition tended to cause tin to crystallized out into "tin whiskers," which reached across chips and shorted them out. It caused all sorts of failures, including a false alarm at a nuclear power plant! The point of that example is that the definition of what technology we will take "on faith" is constantly changing. Ten years ago, the idea of crystals shorting out our electronic circuits would have been one of those "oh yeah, I'll trust you. You're the author, it's your story" type of plot devices. Five years ago, it was considered to be science fact. If the amount of faith we are willing to give technology changes that fast, you can see why technology starts to receive a magical treatment 100 or 1000 years from now in stories. As for your second and third arguments, I agree that technological limitations are interesting. Just take a look at Apollo 13, which was a fascinating exercise in what could be done within limitations. However, I'm not convinced they're easier to work with than magical limitations. Technological limitations have a tendency to be very pass/fail. Either the whole idea works perfectly, or it fails catastrophically. Neither of these make for all that interesting of stories. The interesting stuff appears when the idea works *just enough* that the characters in the story feel some desire to expend effort to make it work all the way. It turns out that sitting in that narrow band between pass and fail is hard. It's much easier to do with magic because you can have looser definitions. And do remember that every one of those limitations must be understood (see the first rule). As an example, consider AGIs: Artifical General Intelligences. They seem like a natural extrapolation of our current AIs. However, it can be tricky. Many of the mathematical tools you use to extrapolate from AI to AGI break down in funny places. I have a long history on this forum of abusing Godel's Incompleteness Theorem to poke at issues that arise when you naively extrapolate in this way. However, explaining this theorem is not easy. In fact Douglas Hofstadter spent an entire book on the topic, *Godel Escher Bach*. The limits put in place by the incompleteness theorems are not trivial to understand, so may call for "on faith" arguments which are bad if you're applying Sanderson's Law. In all, the true complexity of technology is oft stranger than fiction, and its limiting cases can be positively bizare. Consider the sound barrier. As you pass through the sound barrier, you pass across an asymptotic in the velocity/pressure curve. Once on the other side, pressure actually has the opposite effect intended. This causes control surfaces to behave *backwards* once you cross the sound barrier. Modern supersonic aircraft handle this in their fly-by wire system, but pioneers such as Chuck Yeager had to address it manually! (Just one more example of why Chuck Yeager was such a bad ass!) Well, almost. I'll have to be straight with you: all of that stuff about the sound barrier was made up. It was actually a movie plot for a movie released in the era of Chuck Yeager's famous flight, as recounted in his autobiography (EDIT: according to a4android, the film was *The Sound Barrier*. Thanks!). When asked about whether this effect occurred, he simply stated that, had it actually happened that way, he'd have been dead. If I managed to fool you with the previous paragraph, it goes to show just how far our faith in science and technology goes. *(Don't worry, all of the other examples I chose in this answer are indeed real life examples. That was the only fake one)* The actual effect Yeager faced was that, as he crossed the sound barrier, he lost all elevator control. He could not control his pitch up and down. This actually stalled efforts to break the sound barrier for a bit while they tried to figure out what happened. The actual cause was the shockwave from the tip of his nose passed across a hinge on the elevator and created enough pressure to prevent it from moving properly. Once he punched through the barrier, the shockwave moved to a different place, and he regained control. Oh, and control reversal *is* a real phenomena, but it occurs for completely different reasons. The Supermarine Spitfire had an issue with this due to insufficient torsional stiffness in the wing. In some of its extreme dives, the air forces on the wings were sufficient that the ailerons stopped functioning properly. If you commanded the ailerons to go one way, they'd actually end up twisting the wing the other way and the net effect was that the plane would roll in the opposite direction from what the pilot intended! So maybe the truth really is stranger than fiction. [Answer] Off hand, I would say that using sufficiently advanced technology doesn't bypass Sanderson's First Law at all. We actually don't know how this advanced technology would work. It would operate under some scientific principle we don't know... unless the writer explains it. Even if you are just using better versions of existing tech, the idea would then be that the reader should know what technology the character's have access to. That's the entire point of Sanderson's First Law; making sure the options characters have at hand to solve problems are known before they are needed. If you say your character has a teleport belt that can teleport them anywhere they can see or a super-smart-phone that can shoot lasers, that's fine; we don't exactly need to know why it works. But, if you declare they have it right when they need it, then you've got a deus ex machina; you failed to explain the characters options beforehand. ]
[Question] [ If armored airships, equivalent to ocean based ships like battleships in size/armor existed, how would combat be carried out? Assume there is some kind of unobtanium that does away with the gas bag and allows for battleship proportions, the mechanics of which isn't relevant. Assume WW1 or WW2 technology outside this unobtanium. I'm guessing big guns like their naval counterparts would be impractical due to various factors like recoil, increased maneuverability, and angling the turret unless they chose to come very close to each other like broadsides. Perhaps ramming or boarding action but I'm not sure they would be practical. [Answer] Honestly, there isn’t really enough information in the question about how they’re kept aloft to really distinctly answer without making assumptions. So, as such, I’m going to make a few for the first answer. Namely the unobtainum engine doesn’t scale down well enough to work in conventional aircraft (i.e. say, weight limit 100 t or so, I dunno.) .That it doubles as a propulsion source to give your airships comparable sea ship velocities at seaish level. Since it doesn’t scale down well, and can double as a propulsion source, I sort of assume that it produces its lift as a discrete force where it is, as opposed to a lift field or something. I will probably edit the response if you give a bit more info about precise mechanics/limits/to clean up the answer. Anyway... If we work under these assumptions (which give you functionally WWII naval ships in the sky), you end with a pretty scary military unit that still has some glaring vulnerabilities. --- ## Short Version You're looking at more survivable ships of simmilar size mounting a more spread out array of light guns (4-8 inch, depending on size), and depending on the class, the top deck will likely mount some medium and capital armaments for long range ground shelling and heavy airship brawls. Overall, there's a focus on smaller more rapidly firing armaments that can more reliably score hits on other airships and keep conventional aircraft at bay. Because long range combat involves elevating your guns upwards anyway, the heavy armament pretty much stays on top of the ship. Aircraft have a lot more trouble on the offence, since they're functionally lose the altitude advantage they have against surface ships, and near misses no longer cause nearly as much damage, if any at all. It's more than likely that specific anti-airship attacker craft are developed. Transporting a lot of cargo across treacherous terrain becomes a lot easier, and lack of air support of any variety becomes a huge threat to ground forces, especially in open terrain. They're good, extremely useful assets, but by no means infallible, and aircraft are by far still a huge threat to them. But a lot depends on how high exactly they can fly. --- ## Durability Now see, in normal ship operations, most of your gear doesn’t work very well underwater, this is why when you sink a ship, it functionally becomes a non-threat. Cannons don’t function well under water at all, and the electronics and engines don’t fare much better, and it doesn’t help that the crew need air to not die. Generally, sinking a ship means poking enough holes in it that enough of the air inside the ship gets replaced with water, the ship becomes negatively buoyant, and it goes into the largely unstoppable process of sinking. If we have our airships however, the only real way to disable them completely is to nail enough of the structure that it falls apart, or, destroy enough of your unobtainum so it literally drops out of the sky/flips/capsizes. Both of these are more likely to occur at much more dire circumstances then what would sink an ordinary ship, since well, you’ve hopefully armoured your ship enough that doing significant damage to the structure requires a lot of damage across the ship (meaning really, magazine explosions would be the most potent damage occurrences). The other method, damaging the reactors (because really, you’d need more than one) is difficult because they’re most likely the best protected component of the ship, likely mounted as far from the extremities of the ship as reasonably possible. Of course, just with real ships, disabling it doesn’t always mean completely destroying it. A ship that’s set on fire in the air is likely more vulnerable than a normal seagoing ship, as while you could potentially operate at high altitudes where keeping a fire going is difficult, there’s the fact that such a fire would be higher risk for the crew and significantly more difficult to put out, leading to a higher risk of ammo cook-off. The end result is that your ships are arguably more durable than a conventional seafaring counterpart, which is saying a lot considering just how much punishment some WWII ships took. However, while this is somewhat a defensive benefit over seagoing ships, there’s a much, much more prominent one at play here, and that is the agility. --- ## Movement See, with naval ships, you functionally only really have two dimensions of movement, and even then, you’re limited to sort of forwards backwards + turning. Even if you assume the minimum increase in movement, i.e. altitude gain cannot be done independent of forward propulsion (which is kind of unlikely), you’re still dealing with another dimension in which they can perform evasive actions. Functionally, this squares the area in which they can be in any given future reference point, which makes them significantly harder to target than a comparable seafaring opponent. Not only that but high explosive near misses designed to work on surface impact are no longer a thing, meaning even more precision is required to land even glancing hits. Without the water to carry the shockwave, combined with the fact that shrapnel isn’t exactly the most effective weapon for dealing with thick steel plate means that there is a huge jump in durability from this simple adding of a dimension. It once again depends on how the unobtanium works, but the altitude limits could have a very strong effect on the interplay between these ships and other military assets. But I’ll cover that after I cover their armament distribution. --- ## Weaponry One of the primary disadvantages about dealing with the third dimension is that now you functionally have to look in a new direction, downwards, especially if you want to use your airships to project force to the ground. However, cannons firing at longer ranges still need to tilt upwards in order to maximise their range, something that would be severely limited by mounting them on the underside of the ship. Of course, when functioning at long range, mounting your cannons on the top is ideal. It gives you enough elevation to fire at longer ranges, and well, the shell’s arcs are parabolic, so as long as what you’re firing at isn’t too close, you can just shoot from the top deck anyway and have it fall back down to your target. This fact, combined with the prospect of WWII technology (Heavily armoured moving casemates with full rotation on the bottom of the ship would more than likely not have enough structural integrity to not fall out) means that weaponry mounted on the underside would most likely be smaller dual purpose armaments for precision bombing or dedicated AA weapons designed to suppress enemy aircraft climbing to engage. Similarly, such armaments would likely be installed on the sides (front, rear, and port/starboard, depending on the dimensions) of the airship as well, to allow for engagement of other airships at closer, lower elevations. Indeed, even on the top of the deck, it would be more likely that there would be a higher number of smaller calibre guns with higher rate of fire as opposed to the generally larger battery arrangement found on surface battleships, as a product of both the increased weight from the secondary armaments on the side and bottom, and the fact that air engagements at longer ranges would be significantly less practical, due to the higher degree of movement capable. Hence, there would be less of a precedence towards all big gun battleships, and instead a likely heavier focus on heavy cruisers or somewhat smaller ships. Despite this, big gun battleships would still have a prominent place, as their increased range of fire would still offer an advantage in engagements at longer ranges, and the increased shell payload would still play a role in surface bombardment and the occasional lucky hit on a ship. This is doubly so, as a battleship with long range artillery guns at high altitude could potentially shell a city or other large target with complete immunity any form of ground based counter attack. Only aircraft or airships would pose a threat at all. Unlike WW II, a big difference would be in the lack of submarines and their torpedoes (and well really torpedoes in general). Since you’re now in the air and we assume that the unobtainium wouldn’t feasibly work on a small object, not to mention that WWII era torpedoes don’t have seeking guidance (rather, they could turn to face a direction and that’s it), combined with the fact that there are now three dimensions of movement means that even if they did work, they’d be functionally useless. Honestly, I have no idea how they managed to actually score so many hits in WW2 with them from ships (well I sort of do, 2 dimensions and one direction of travel means you can shoot a whole bunch along the path of where the enemy is going, and hope they don’t notice/can’t evade in time). Either way, they’d either not exist, or be worthless for hitting anything. Most of the other ship classes would probably exist however. Carriers would be obvious, and the entire gun toting-warship line would also exist, considering that you don’t always want the biggest gun, but sometimes you want to bring a bigger gun. Speaking of carriers, the interaction between these an aircraft would most likely end up similar, but significantly less advantageous towards the aircraft, for a few reasons. --- ## Aircraft See, the problem with the vast majority of WWII aircraft is that most of them can only really deal significant damage to such a warship via the use of bombs or rockets (for smaller ships or more vulnerable subsystems on larger ones). And during WW2, neither were exactly the most accurate of weapons. And the star of sinking ships in WW2, the torpedo, is pretty much absent for much of the early war, assuming the later inventions (glide/radar guided bombs) are invented later in the war. Indeed, this is probably the biggest factor that lowers the number of airship sinking occurrences until more advanced weapons tech picks up. With the higher evasiveness of airships, you’re looking extremely low hit rates on bombs, especially now that glancing hits have a lot harder time causing damage. And rockets for a good degree of accuracy require doing the same sort of suicide run that a torpedo bomber needed to perform, namely, flying directly at the target to ensure the airflow over the rockets is stable and their accuracy is at its maximum. And unlike torpedoes, where you only need to match two dimensions of movement, rockets arc on a trajectory, and with the airships, would need to account for it's additional directional movement. The biggest difference however, is the altitude that the aircraft have to tackle them at. See, a big aspect of aircraft performance is the operational altitude. Many of the attacker aircraft that were used to perform high precision airstrikes worked well primarily only at lower altitudes where their high lift co-efficient made up for the fact that they were carrying potentially more than a ton of ordnance. This effect becomes significantly more prominent the higher our airships can effectively fly, since the higher they can safely go, the more of the agility they can functionally rob from the attacker aircraft, making them easier to intercept or shoot down, especially given that they would need an altitude advantage over the ship in order to effectively bomb it using freefall ordinance. Once we start getting real high up (about 10 km up), it starts becoming more of only a few aircraft can functionally reach your airships in the first place. Cloud cover would also play a significant role in attacking airships, as the double blind scenario it causes can effectively prevent any attack on the ship while it is enshrouded, but at best it can only burn the opposing side’s fuel reserves as they wait for the cloud to disperse or the ship to move out of it, and at worst, results in a aircraft crashing into the ship while both are moving through the cloud. Regardless, despite the sum of effects, aircraft would still function as an effective fighting force against airships, contributing as one of the larger killers still, if not the largest. This would likely be the result of divergent development of weapons technology. --- ## Countering Given their (I assume) prolonged presence in the setting, even at a WW2 tech level, there would be divergences in terms of weapons development, especially in relation to aircraft. Development of rocketry based payloads would likely see more aggressive development, along with smaller more stable glide bombs for hitting airships (functionally replacing the surface based torpedo payload option with either large rockets or glide bombs). Not only this, but given the significant risk increase in fires on board airships, there would be a higher focus on development of dispersion weapons designed to set alight the airships with a smaller or lighter load than conventional high explosive payloads. The use of clustering or area dispersal weapons in particular would’ve likely seen more significant development, allowing a craft on a quick attack run to still potentially cause some damage to more vulnerable or exposed systems on an airship. Not only that, but the prominence of cannon mounting aircraft such as the B-25-G, Ju 88p-1, Mosquito FB Mk XVIII and Hs 129B-3 etc. would’ve likely been increased, as the relatively accurate higher calibre cannon fire would still have an effect on the larger more armoured airships, and they would’ve likely seen more advanced development in building more capable airframes to mount such airborne weapons. In terms of surface based equipment, minimal forest cover could help significantly camouflage stationary weapons batteries of artillery calibre anti-airship guns, though such mountings would most likely be extremely vulnerable to counter assaults, especially from the ground. Functionally, they’d have the advantage of being significantly more spread out and better hidden, but lack the resistance to direct attacks an airship would have. They’d also probably be a lot cheaper to produce than an airship with comparable function. You’d still need to score direct hits though, which would limit their effectiveness, but airship to airship combat has the same caveats (bar the fact the airships can close the distance to increase both risk and success rate). Of course, once the more advanced guided rocketry and jet engine technology started running around, they would seriously start feeling it, just like their original surface based equivalents. Their lower vulnerability to sinking would help keep them going for longer, but it would give everything a reasonable method of delivering a lot of punch with accuracy, at which point, the added armour isn’t nearly as helpful. Those ground based hidden batteries would only need one shot to potentially cripple any counter offensive, and their large profile makes detection easier and landing hits more so, while they can’t counter the much smaller, hidden opponents first. --- ## As an asset That being said, at a WW2 tech level, they would make extremely good assets. They would combine a Heavy bomber and warship in one nicely armoured package, and would have minimal limitations on where they could be used. But their transport capabilities would be equal to, if not outshine, their combat capabilities. The ability to land thousands of tons of war material at anywhere large enough, ignoring the intervening terrain, would change the face of wartime logistics. Depending on their operational altitude, they could safely travel in fleet formations that would be vulnerable only to large aircraft formations or other opposing fleets of airships. Air combat would become a lot more significant and yet, intercepting airships would more a more costly move than intercepting warships. The lack of a “stealthy” attacker like a submarine would mean that commerce raiding could only really be done by opposing airships or, in the case of supply fleets not supported by escort carriers or air assets, opposing aircraft. The high launch altitude would give the defending air forces a significant edge in rapidly responding to enemy attacks. Despite this though, even with their usage as mobile armoured artillery, conventional ground and air combat would most certainly remain a central aspect of battle. Aircraft would still retain their relatively extreme range compared to artillery weapons, even if airships could travel through the sky. And in the end, most of what wars are fought over is the ground territory, while you can project force, troops, firepower etc. with your airships, you can’t really head in and secure it without ground troops or vehicles, especially if you want to leave any of the infrastructure intact. Identifying fleet numbers, their locations and whatnot would be a significant part of countering them. After all, each ship can carry potentially thousands of paratroopers alone, and have enough artillery to provide support until more reinforcements arrive. Visually spotting an airship at day might be easy, but once night falls, detecting them becomes much harder and radar detection becomes a more vital aspect. [Answer] > > *If armored airships, equivalent to ocean based ships like battleships in size/armor existed, how would combat be carried out?* > > > It would be a slaughter. No, I mean ***the flying battleships would be slaughtered***. Big gun, heavily armored battleships disappeared from the sea for a reason, and those reasons would be even worse in the air. Just like their sea-going counterparts, they'd be chewed up by combat aircraft. In short, prior to WWII the effectiveness of airplanes as weapon delivery systems reached a point where a flight of cheap, fast, long range aircraft could sink a battleship long before their guns ever came into range of the enemy. No amount of armor or defenses could prevent this... except more aircraft. This was made clear early in the war by events such as the [Battle of Taranto](https://en.wikipedia.org/wiki/Battle_of_Taranto), [Pearl Harbor](https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor), and the [sinking of Force Z](https://en.wikipedia.org/wiki/Sinking_of_Prince_of_Wales_and_Repulse). The ineffectiveness of battleships against carriers was brought to its absurd conclusion in the [Battle of Leyte Gulf](https://en.wikipedia.org/wiki/Battle_of_Leyte_Gulf) when one of the largest surface combat fleets in the world including the [Yamato](https://en.wikipedia.org/wiki/Japanese_battleship_Yamato), but lacking air cover, was repulsed by a bunch of [small escort carriers](https://en.wikipedia.org/wiki/Escort_carrier) and destroyers who were there for anti-submarine defense and ground support. ***Battleships could only operate with sufficient air cover***. They were reduced to shore bombardment and anti-aircraft defense, things which much cheaper ships could do. After WWII they were scraped. --- Putting one in the air just makes this all far, far worse. A battleship on the surface of the ocean has the sea and curving horizon to hide them. Prior to radar the enemy had to literally fly over a battleship, or sight it by eye, to detect it. But ***a battleship sized airship would stick out like a sore thumb for hundreds of miles away*** and far outside the range of its weapons. Air combat is designed to detect and intercept small aircraft traveling at high speed, possibly with stealth characteristics. Something as large and slow as a battleship would be picked up hundreds of miles out. Air defenses would concentrate long its projected line of advance. As it lumbered its way forward, [surface-to-air missiles](https://en.wikipedia.org/wiki/Surface-to-air_missile) and intercept aircraft could attack it for *hours*. ***Much like a WWII bomber formation or battleship, the air battleship would need its own extensive air fleet to defend it***. --- An armored airship powered by Unobtanium does have *one* advantage: armor. But WWII anti-aircraft guns fired large shells at high velocity to reach high altitudes, perfect for penetrating armor. [The famous German 88mm anti-tank gun was adapted from an AA gun](https://en.wikipedia.org/wiki/8.8_cm_Flak_18/36/37/41#Support_of_ground_troops). Designed to fire at smaller, faster bombers, they would easily hit a large, slow moving airship. The shell would lose energy the higher it flew, so how much armor it could penetrate depends on how high the battleship is flying, but [you can't armor everything](https://en.wikipedia.org/wiki/All_or_nothing_%28armor%29), and vulnerable, exposed equipment such as control surfaces, propulsion, and rangefinders could be wrecked as the battleship slowly lumbered by. Traditional WWII air-to-air weapons would have a difficult time. The usual .50 cal and 20mm cannons of the day would be effective in strafing runs against exposed crew positions, as they were against naval ships, but would not penetrate the [armored citadel](https://en.wikipedia.org/wiki/Armored_citadel). For that they would use air-to-ground ordinance such as rockets, heavy cannon, even bombs against the slow moving air battleship. ***Ground and naval attack aircraft such as the [Il-2 Sturmovik](https://en.wikipedia.org/wiki/Ilyushin_Il-2) and the [TBF Avenger](https://en.wikipedia.org/wiki/Grumman_TBF_Avenger#Specifications_.28TBF_Avenger.29) would work just as well against a slow airship as they did against ground and naval targets***. Worse, that same Unobtanium can be applied to the attacking aircraft. Small, fast, *armored* attack aircraft are a far more difficult problem. More on that below. --- Damage control will be a problem. A damaged sea-going battleship has three things to worry about: sinking, rolling over, and the worst of them all *fire*. Sinking is a matter of remaining less dense than water. This can be assured with simple technology such as [water-tight compartments](https://en.wikipedia.org/wiki/Compartment_%28ship%29) and pumps to maintain buoyancy. A top-heavy battleship is in danger of rolling over, but this can be dealt with by counter-flooding. Fire is very dangerous, but at least they have all that sea water to pump in. In an extreme case, a whole compartment can be flooded to prevent an ammunition explosion. Air battleships don't have to be top-heavy, they don't have to put everything on top, so rolling over is not much of a danger. But it has to maintain its buoyancy. Instead of being less dense than water, ***a flying battleship has to be less dense than air***. This makes it much more vulnerable to damage to whatever mechanism keeps it in the sky. Unlike a sea-going vessel, it can't just pump out the air. Finally, once it's set on fire it cannot pump in seawater or flood compartments. ***A flying battleship has to carry all its own firefighting supplies***. --- Guns on a battleship might be handy for bombardment, but then it would be in range of ground fire. AA batteries and artillery from miles around would fire at the huge target in the sky. ***Ramming is laughably off the table, for the same reason WWII naval warships didn't do it***. Even if the enemy commits the same mistake and builds their own air battleships, WWII weaponry is so devastating, so accurate, and so long ranged that the ships would destroy each other long before they reached boarding range. ***The battleship would have to be protected against conventional air attack just like surface ships were***, by as many AA guns as they could cram in. Larger, longer range guns would fire too slow to have any hope of hitting a fast maneuvering combat aircraft. Normally aircraft don't have armor because lifting all that extra weight costs fuel, speed and maneuverability. But if your battleship can do it with Unobtanium, then so can the attacking aircraft, and far more efficiently. Now those very AA weapons which bounce harmlessly off your battleship armor also bounce harmlessly off the attacking aircraft. And damaging a fast moving, hard maneuvering *armored* combat aircraft is a much harder problem than dropping a bomb on your big, slow battleship. --- In the end, it's a boondoggle. Such a weapon would be very expensive, very vulnerable, and very slow. It could only operate with local air superiority, even then it would be very vulnerable to ground fire. Every time it moved, the enemy would track it. If it moved toward the front, the enemy would know exactly where you're going to attack. All that firepower could only be in once place at a time. Once it's damaged or destroyed a large chunk of your firepower is gone. It would play out much like [the death of the battleship Yamato at the end of WWII](https://en.wikipedia.org/wiki/Operation_Ten-Go). ***Capital ships are a colossal waste of resources***. A single [Iowa class battleship](https://en.wikipedia.org/wiki/Iowa-class_battleship) cost \$100 million in the 1940s, plus all the special, colossal infrastructure to build and maintain it. A [B-29 bomber](https://en.wikipedia.org/wiki/Boeing_B-29_Superfortress) cost about \$600,000 and a [P-51 Mustang](https://en.wikipedia.org/wiki/North_American_P-51_Mustang) about \$50,000. For the cost of one air battleship your enemy could build 150 top of the line heavy bombers or 2000 long range interceptors. These could also be augmented with Unobtanium increasing their buoyancy and thus allowing additional payload and armor. [Answer] Just reduce the recoil of the cannons until the mass of the ships is sufficient to negate it. The first method is to absorb the recoil by making parts of the weapon move backwards. This works because the ship is presumably quite massive compared to the projectile, so the velocity imparted to ship is very small compared to the one of the projectile. This does apply even to aircraft. A10 for example is notorious for having a really big gun, but apart from requiring proper design to avoid breaking the aircraft it doesn't really cause issues. A projectile pretty much has to be relatively light in comparison to an aircraft carrying thousands of rounds of ammunition and a cannon capable of firing them, after all. The other way is to use the gas propelling the projectile as the counter. In a recoilless rifle a part of the propellant is used to produce a back blast that counters the recoil. Such are used currently as man portable anti-vehicle weapons. A rocket launcher is of course an alternative to this. In other weapons the muzzle blast is captured after leaving the muzzle and redirected backwards. This also makes the weapon less visible and noisy, since the gasses have more time to cool and slow down before being released. This isn't usually done with cannon since it isn't generally that useful and is difficult with some types of ammunition, but you could have your airships mount "low visibility cannon", if you can think of a rationale for it to have value. It could make firing back more difficult during night operations. [Answer] It would probably be just like sea combat except you would have guns stationed at the bottom as well as the top, because in air combat you have to worry about attacks from enemy air craft coming beneath as well as above. [Answer] This has been a concept I have toyed with for a long time. The primary goal in this theoretical airship combat would be to bring the other aircraft down or kill all crew members aboard. Since these airships are using traditional zeppelin design, the gas bags would have to be torn open from the top. WWI zeppelins kept the pressure of the gas bags at about 84%, meaning they would not deflate. Another factor to take into account is the zeppelin's fairly fragile internal structure and the fact that it is airborne; recoil either has to be negligible or non existent. We need a recoilless weapon that strikes from above. Perhaps an enlarged version of the M2 4.2 inch mortar. This would recquire the airships to get closer to each other in order to engage in combat. Another option would be to kill all the crew members. I have no how this might be achieved but it might be something to think about. Something else to think about would be the airship's vulnerability to flak shells. Radar was around in WWII and hulking airships wouldn't be hard to spot. I know that this is all about airships fighting each other, but I think it would be more realistic (albeit way lamer) if planes were used to bring down and protect airships while the airships themselves were used to carry troops, bombs, supplies, etc. I would also like to propose the idea of giant flying fortresses that can't move. Like barrage blimps except they are dirigible and are bristling with AA weaponry and air held down by huge chains. [Answer] If your society has WW1 technology, then cannon would probably be used. If it was WW2 tech, then aircraft carrying bombs would be used - much greater range and accuracy as opposed to mounted cannon. Far harder to hit a fast moving aircraft than a relatively slow moving battleship. ]
[Question] [ Could a large, aggressive bird of prey take an aircraft the size and weight of two motorcycles out of the sky? The bird is about the size of a child, but has sentient intellect. If it got through the airships weak armor, (tap your computer chassis, that's how thick) could it damage internal systems enough to destroy it, or at least put it out of control? I'm working on a game project so it don't need *exact* results, but I was just wondering if this would look absolutely absurd while happening. The airship turbine driven so there is no danger of the bird getting it's flight pattern or getting shredded by turbines. Think like the snow speeders from *Star Wars*, but lighter. The bird has the general specifications of a crow, aside from size of course, and is trying to take down the craft in any way possible, if that's damaging it enough for it to blow up on the ground, the sure, he'll do that, but would rather hit a cable or something to get it to blow up midair (after a timely disengage). The envelope would be to heavily protected in the *center* with the rest of the ship built around it, so tearing it really isn't too much of a possibility. [Answer] If it is a lighter then air airship the bird of that size should be able to damage the envelope enough that it would crash. If it is a regular aircraft of some sort the bird should still be able to destroy especially it's smart about it. Aircraft require a relatively delicate balance to remain airborne and controllable so even a little damage in the right spot can crash them. I don't exactly the kind of aircraft you mean, but breaking the tail will render most types of airplanes and helicopters unflyable. The tricky part is the airship's speed, if it is faster then the bird, the moment the bird makes contact with can be very dangerous, depending on the difference it can cause the leg to break when the bird grabs it or worse. So generally yes, but could be dangerous for the bird if the aircraft is fast. [Answer] Yeah, that's possible. Though, the birds usually die in the process. An entry [from here](http://en.wikipedia.org/wiki/Bird_strike#Incidents): > > On January 15, 2009, US Airways Flight 1549 from LaGuardia Airport to Charlotte/Douglas International Airport ditched into the Hudson River after experiencing a loss of both turbines. It is suspected that the engine failure was caused by running into a flock of geese at an altitude of about 975 m (3,200 feet), shortly after takeoff. > > > With the bird being about the size of a child, an unnerving image, it would be easy for it to simply carry something to throw into the turbines. Perhaps something like a grappling hook, not for its intended purpose, but just because it is a chunk of metal with some tangling metal cable on the end of it. [Answer] Since your bird is intelligent (and quite large), if it wants to bring down an aircraft, the simplest way would be to attack the control panes. Especially the elevator: if the bird manages to push down the elevator (it need not even be far down) and then manages to lock it, for example by something as simple as wedging a piece of wood in the gap, that would bring the aircraft down very quickly, without having to bother with damaging any part of the craft. [Answer] A sentient bird would probably cary some tools. The character in *Rio 2* used a fanny pack during a long migration, and that's not realistic. I can imagine multiple implements (like the leaves in a Swiss Army Knife) strapped around the legs, or a belly pouch held very close to the body. Perhaps it could be more voluminous if it was curved to give a good aerodynamic shape. Finally, notice that a bird's *neck* is rather thin and the area filled out with feathers to shape the body contour. There is room under there to tuck a utility necklace without showing at all. A sentient bird would carry a few things to suppliment his hands and strength, especially if a guest in an environment made by another species. So he may have a stiff and strong tool like a "wonder bar", and a knife, and some wrap to serve as grip wrapping or a strap wrench. If taking off with foreknowledge of the task, he would pack something to help with that. Like, a carpet knife blade. Thus, he would have no trouble destroying the gas envelopes. Sure, *holes* are remarkably ineffective, but start cutting a long line and make a gaping cavity that will not function as a bag. If it's going down, attacking the control surfaces won't help much, unless it's to prevent them from aiming for a clearing. If the lifting gas is hydrogen, as would be the case in a low tech setting or if helium is simply not available, then a flare would do some damage once a hole is made. [Answer] If the aircraft has wings and depends on aerodynamic lift then the best way would be for the bird to perch on one wingtip and pull up hard: their wings probably have more roll authority than the aircraft control surfaces. However a serious problem for the birds is probably going to be catching up with the aircraft in the first place. "Two motorcycles" is maybe 400 to 500 kg, so thats a "[light sport](https://en.wikipedia.org/wiki/Light-sport_aircraft)" aircraft. Something like that might do 100 knots or more. Its going to be a pretty remarkable bird that can match that in level flight (imagine a man on horseback trying to catch a car). So they are going to have to wait above the flight level, dive to match speed, and grab hold of the aircraft, which will presumably be manouvering to avoid them. Tricky, and if they miss then they don't get a second attack because the aircraft will leave them behind. Also, what defense will the aircraft have? You mentioned armor, but sharp edges and electric shock systems spring to mind, as well as projectile weapons wielded by the pilot or passenger. [Answer] If the airship has propellers or jet engines and the birds are intelligent and don't want to sacrifice themselves then dropping rocks, nets, rope or cable onto or into the engines would probably work pretty well. Depending on their intelligence there's other options as well. I imagine a powder charge or bags of iron filings would do terrible things if thrown into a jet engine. ]
[Question] [ Carbon dominates the makeup of life on Earth. But is there any way that plants could be made out of metals, or somehow integrate metals with their constitution? For example, we use calcium in our bones, which is an alkaline metal. Its there any way that a plant might use metals (alkali or otherwise) to strengthen its structure so as to resist strong winds and protect itself from predators? [Answer] Lets look at some real-world examples of plants which already absorb and use metals, namely [hyperaccumulators](https://en.wikipedia.org/wiki/Hyperaccumulator). ![Hyperaccumulating plants already use metals within their tissues.](https://i.stack.imgur.com/RrHre.jpg) Hyeraccumulators are plants which can withstand extremely high concentrations of metals otherwise toxic to non-hyperaccumulating plants. They extract metals from the soil and store them within leaves, shoots and their roots. Other plants can also extract metals from soils, but hyperaccumulators can do this at a much, *much* faster rate and are also able to store incredible quantities of these toxic metals within their tissues. Because of this extraction of metals, hyperaccumulators are commonly used in [phytomining](http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/metalsanduses/extractingmetalsrev5.shtml), where we use such plants to take minerals out of the soil for us. ![phytomining process](https://i.stack.imgur.com/gcxGp.jpg) Of course, hyperaccumulators absorb many metals, not just the ones valuable to humans. Because of the toxicity of the metals which are absorbed by hyperaccumulating plants, scientists speculate that the primary purpose of hyperaccumulation, at least, the primary defensive purpose, is to prevent them from being eaten. The concentration of toxic metals within these plants is so high that animals which eat them will die, and so never be found eating them again. ![Toxic metals used mainly to deter animals.](https://i.stack.imgur.com/w8J5f.jpg) So, here on Earth, hyperaccumulators only pad their tissues with toxic metals to decrease the likelihood of their being eaten, but you've stated specific interest in using metals to improve structure, rigidity and strength. However, if a plant were able to pull metals from the ground like a hyperaccumulator, there's no reason those metals couldn't then be used to strengthen the plant. First, let's have a look at which metals hyperaccumulators are known to handle: ``` Name Symbol UTS tensile strength Aluminium Al 700 Silver Ag 170 Arsenic As 3 Beryllium Be 448 Chromium Cr 689 Copper Cu 220 Manganese Mn - Mercury Hg - Molybdenum Mo 690 Disclaimer: Lead Pb 17 I am pretty certain that the Palladium Pd 325 listed tensile strengths are Platinum Pt 240 inaccurate and inconsistent. Selenium Se 500 They should be used just as a Zinc Zn 28 rough idea of the actual strengths. ``` From this list, two metals stand out; Aluminium and Chromium. ![Al/13/27 Cr/24/52](https://i.stack.imgur.com/Buc9m.jpg) Both incredibly strong metals; this is the same Aluminium used in [skyscrapers and jet engines](http://www.riotintoalcan.com/ENG/ourproducts/1542_aluminium_and_its_uses.asp), and the same chromium as used in [Chrome plating](https://en.wikipedia.org/wiki/Chrome_plating). If your plants were to hyperaccumulate large enough quantities of these metals, they could capitalise on their strength in many ways. Some examples I thought of were: * Reinforcing cell-walls by chrome plating. Currently, plant cell walls are made almost entirely from [cellulose](https://en.wikipedia.org/wiki/Cellulose), which is (compared to chromium) very weak. By reinforcing this cellulose with chromium, individual cells of your plant would become nigh-indestructable. * Building skeletal systems. Along with the [Phloem](https://en.wikipedia.org/wiki/Phloem) and [Xylem](https://en.wikipedia.org/wiki/Xylem) of current plants, metal plants might have a third system of vessels, filled with Aluminium, keeping the plant structurally sound. Good luck snapping a twig laced with one of the toughest metals of which we know. * Plating the entire plant. If the plant's [epidermis](http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/L/Leaf.html) were to secrete chromium instead of wax, it could build up a thick layer of chrome plating, which cannot be scratched, corroded or otherwise damaged. ![Metal plant uses chrome-plating to protect itself.](https://i.stack.imgur.com/BioUa.jpg) Of course, now that you have the ability to absorb minerals and metals from the ground, you can use them however you want! [Answer] As you stated previously we use calcium in our bones but, given several bone sustenance changes, it would be trivial to use said calcium to create skeleton based flora. Unfortunately... ### Where do we get it? On average soil is around a tiny 1 percent calcium. If your goal is to reinforce the plant, then this might work if you add small amounts of hydroxyapatite(bone) to the cell walls of the plant but not if want a complete skeleton. For that i suggest. ### Carnivorous Plants The human body, and most other large animals, contain a great amount of calcium just waiting to be used by your potential plant. Although large carnivorous plants are more fantastical they would allow for the vast need of calcium to be met. [Answer] Not carbon-based plants as we know them. The advantages like structural strength that you associate with [metals](http://en.wikipedia.org/wiki/Metal#Physical) are generally a result of what [humans have done to the metal](http://en.wikipedia.org/wiki/Metallurgy)—accumulation, processing, and forging/casting or plating. Those processes require a lot of energy, a lot of heat, and a lot of motility, none of which plants are going to be able to pull off or survive on their own. Metals as they exist naturally are not generally useful for their metallic properties. They are almost always bound in some sort of ore, highly impure, rare even within the mass of the ore, and they usually require considerable and energy-intensive physical and chemical [processing](http://en.wikipedia.org/wiki/Extractive_metallurgy) before you get a usable quantity of elemental metal. At that point, even more processing must be done. Two of the basic properties of metals are ductility and malleability, which are the ability to deform under tensile or compressive stress. **Thus metals aren't known for their ability to withstand stress, but rather for their ability to deform under it without fracturing.** The metals known or used for their strength or rigidity owe that strength to a crystal structure imparted by the process of [forging](http://en.wikipedia.org/wiki/Forging) or [casting](http://en.wikipedia.org/wiki/Casting). Those processes require levels of heat (the metal has to melt) which are impossible for any carbon-based lifeform to create on its own without technology or to withstand at close range. Electroplating, a process used to coat things in useful metals—although usually for corrosion-resistance or decoration (which are the reasons you know what chrome is) and not for strength—is both energy-intensive and an electrochemical, technological process. Plants aren't going to be able to use or survive plating. Even if they could, metals are opaque to sunlight, so any plant coated in them won't be able to survive. Besides, plants already have the use of another light-weight, rigid material for structural strength: [cellulose](http://en.wikipedia.org/wiki/Cellulose). Humans were using wood for its strength and rigidity long before we discovered how to work metals. And, while cellulose doesn't have the rigidity of structural steel, it also doesn't have to be heated to 1,539 °C in order to have that strength, which is a big advantage when you're constructing a plant. **tl;dr: You don't get ![structural steel](https://i.stack.imgur.com/UC7t0.png) without ![a lot of heat and technology](https://i.stack.imgur.com/LOEZy.jpg)** ]
[Question] [ In my story, a group of creatures lives on the Moon. I know that microlith striking the Moon is fairly common, to the point that EVA suits are built to compensate for it, but I was planning to have a “meteor shower” kind of deal, where a “rain” of small asteroids or particles hits a small area over a short period (ten minutes or so). This way, the creatures would feel or see the microlith falling at high velocity and be forced to seek shelter, similarly to a very short rainstorm on Earth. Does this really happen at all, or is the impact of micrometeorites more spread out? How frequently would something like this occur? [Answer] Direct micrometeors from space would be way,way,way too rare for this. Impact from something that can be felt, much less something that can be detected ahead of time, would be weeks to many years between single events. But... how about a strong meteor impact a few (dozen? hundred?) km away. What your astronauts are experiencing is the debris that was kicked up by that impact. This would be both vastly more numerous, and much slower than incoming meteors. It will be both detectable, and yet slow enough for them to have time to seek shelter, with debris travel times of several minutes, and speeds of 1-2km/s only [Answer] The only plausible way for what you ask to happen, apart from a close impact, is to have the tail of comet cross the lunar orbit. While producing the tail, the evaporating matter also moves particles away from the comet surface, which then move into space forming the tail. If the tail happens to be intersecting the moon orbit it will end up hitting its surface. However, the phenomenon will be very rare, and moreover particles traveling at few km/s cannot be seen by the naked eye, even more considering that there is no atmosphere to light them up. For a reference, look at some of the images taken by [Philae and Rosetta](https://apod.nasa.gov/apod/ap160202.html) during the landing on the comet. [![enter image description here](https://i.stack.imgur.com/XLpdM.jpg)](https://i.stack.imgur.com/XLpdM.jpg) Some of the brightest spot you see are particles leaving the comet surface. [Answer] **Meteor showers!** We can watch meteor showers on Earth. Most of them burn up in pretty streaks in the sky. Not so on the moon. Every single one plows right into the surface. <https://phys.org/news/2006-12-lunar-leonid.html> > > Meteoroids that hit Earth disintegrate harmlessly (and beautifully) in > the atmosphere. But the Moon has no atmosphere to protect it, so > meteoroids don't stop in the sky. They hit the ground. The vast > majority of these meteoroids are dust-sized, and their impacts are > hardly felt. But bigger debris can gouge a crater in the lunar surface > and explode in a flash of heat and light. Some flashes can be seen > from Earth. > > > During the passage through Tempel-Tuttle's debris field, Cooke's team > trained their telescopes (two 14-inch reflectors located at the > Marshall Space Flight Center) on the dark surface of the Moon. On Nov. > 17th, after less than four hours of watching, they video-recorded two > impacts: a 9th magnitude flash in Oceanus Procellarum (the Ocean of > Storms) and a brighter 8th magnitude flash in the lunar highlands near > crater Gauss. "The flashes we saw were caused by Leonid meteoroids 2 > to 3 inches (5 to 8 cm) in diameter," says Cooke. "They hit with > energies between 0.3 and 0.6 Giga-Joules." In plain language, that's > 150 to 300 pounds of TNT. > > > The Perseid meteors also make impacts on the moon that can be seen from Earth - dozens every year. <https://science.nasa.gov/science-news/science-at-nasa/2008/02sep_lunarperseids> For every big explosion one can see from Earth there are many tiny ones that do not kick up enough light and heat to be seen from Earth, but which would definitely make a divot. Even a milligram of rock coming in from space could make your day a bad one. Actually I did the math: 1 mg moving at 50 km/s has the force of a stick of dynamite. Moon dwellers would definitely pay attention to the periodic meteor showers we know about, and seek cover when they were raining down on the moon. ]
[Question] [ A messiah was sent with the specific purpose of saving humanity from their sins, but unfortunately failed to overcome his human weaknesses. He was said to have an " impatient eye " with the opposite sex and succumbed to his lecherous instincts. This led to demigods being born all over the ancient world, numbering in the hundreds. These demigods were considered superhuman, with abilities far outstripping the capabilities of mortals. They would go on to perform great deeds, such as slaying monsters plaguing the world, or sacking great kingdoms for their nations. Their deeds would inspire many myths and stories about their adventures and conquests, provoking the envy of mortals and inspiring others to live up to their legendary reputations. Gods are considered to be enhanced humans, not only in body but in mind. Every emotion they feel is magnified ten fold, such as love and anger, which led to their dramatic behavior and over-reactions that many of them displayed in myths of the past. Their offspring would naturally possess these qualities, albeit on a lower level than their parents. This is demonstrated in the ancient myths from their overly cruel punishments of mortals to their heroism and fearlessness in battle against monsters. As their egotistical and charismatic behavior is directly linked to their accomplished feats, it isn't that far of a step to desire actual political power as well. The ancient world was a time of might makes right, and the strongest of individuals would naturally seek to dominate others and rule kingdoms. Many kings started out as warlords who conquered some territory and expanded their power base. Demigods could certainly gain the support of the public and would easily overthrow lesser mortals in a struggle for power, seeing as how the ancient world valued the characteristics that they possess. Demigods allowing lesser mortals to lord over them seems opposed to their nature. How can I make this scenario more likely to occur? [Answer] **Are we sure the demi-god can always over-power mortals?** In a mythological setup, mortals are not helpess against demi-gods: there are magical weapons that can equalize the odds, direct interventions of gods that decide to help a mortal in exchange for some favors, and so on. In the Iliad, for instance Diomedes was able to injure Ares/Mars (and I think that in the same book of the Iliad there was another part where Zeus listed all the times when a mortal was able to defeat a god). For this reason, I don't think a demi-god would always rule against mortals: they can manage (even with difficulties) to win against a demi-god. Moreover, in order to rule it is important to always act rationally, which is something that not always happens with the demigods, who are people who use to have strong emotional reactions. A mortal ruler who is able to always think rationally, could easily outsmart a demigod taking advantage of this. Or, in other words, while Sun-Tzu would never defeat Eracles/Hercules in a one-to-one duel, he would easily defeat his armies, which would make him a better leader even if a worse fighter. [Answer] ## Because they don't all want to be rulers Sure, having a load of people at your beck and call is great, but in feudal times any oath of service was a two-way deal. The servant promised to follow the lord's command, pay tithes and fight in their name and in exchange the Lord promises to protect them, be it from acts of God, nature or mortals. Once you get beyond a small handful, managing your underlings problems becomes a real time sink. You have to make sure they're all fed, healthy, clothed, homed. You have to punish troublemakers and settle disputes. This is all really boring, mundane crud unless you are really into it, and most won't be. So instead they may gather a small party of loyal servants to aid them whilst they do whatever it is they actually want, be it hunting down and slaying mighty beasts, developing new, powerful spells, or producing great works of art. Some may even have a mortal Lord as a patron, who will provide them with food, shelter and resources in exchange for a shqre of their considerable talent. [Answer] You could go on and follow examples from ancient Greek myths: 1. The gods say that this particular demigod is destined to serve this king (like [Heracles and Eurystheus](https://en.wikipedia.org/wiki/Heracles#Labours_of_Heracles)) 2. The demigod is happy that his relative has become a king (like [Jason](https://en.wikipedia.org/wiki/Jason)) 3. Demigods just travelling and performing deeds (like [Theseus](https://en.wikipedia.org/wiki/Theseus) at youth). He knows he will be a king one day but doesn't want to get the crown immediately. 4. Demigod has lost a kingdom (in battle, because of intrigues etc.) There are many other options. Just re-read the myths about second-line heroes and you'll find many scenarios :) [Answer] What you are describing is literally the metaplot of *Exalted*. The gods created the Celestial Exalted (Solar, Lunar, and Sidereals) to overthrow the Primordials and rule over humanity as god-kings, and to do this they gave them supernatural powers and superhuman charisma and could do impossible things so long as it looked cool. There were also the Terrestrial Exalted, who were created to be servants and elite footsoldiers of the other Exalted and were much more mundane in power level. The problem for the Celestial Exalted is that their absolute power corrupted them, along with a curse that caused all of their human flaws to be magnified tenfold and cause them to do horrible things in emotional outbursts (much like most depictions of "humanity amplified" demigods). For example Desus, one of the most powerful Solar Exalted, had the power to influence people's minds, and used his ability to physically and mentally abuse his wife as well as rape and torture people and then brainwash everyone around him into thinking that was okay. This abuse of power by the Solars and Lunars caused the Terrestrial Exalted to revolt against their masters (with the help of the Sidereals, who were also corrupted but didn't get the blame for it). The Terrestrials overthrew the Solar and Lunar Exalted and then spent the next six-hundred years making sure they could never come back. They did everything in their power to track down and kill any surviving or newborn Solar and Lunars to make sure they could not rise to power again, and shaped the culture of human civilization such that the populace saw Solar and Lunars at best as unfit to rule, and at worst as horrible monsters that must be destroyed at the first opportunity. At the time the game starts the only surviving Solars and Lunars are a few quasi-legendary figures and barbarian kings living in the far-off hinterlands, as well as the player characters who are often newfound Solars and Lunars that must keep a low profile or be executed by the Terrestrial Exalted. That would be how you do it. **Humanity overthrew the demigods en masse and then took steps to make sure demigods could never seize power again, whether that be killing them whenever they appear or installing a culture-wide fear of them. Legends and stories would be told of why you don't allow these people to have any power, or be highly suspicious of them when they do appear.** Alternatively, you do what *Warhammer 40k* did. Once the kingdoms of men were ruled by overly-emotional, immature demigods, but they wiped themselves out in a great civil war against each other and the few that survived either retreated into seclusion or went into exile. A few might nominally still be around but overall history since that point has been an age of men, not gods. [Answer] *All power that a ruler wields comes from the people that are being ruled.* If people do not want to give power to demigods, demigods will not be able to seize it. Even if demigods are super strong and super smart there are too few of them against too many. So, a better question would be why mortals do not allow demigods to rule over them. Some of the possible explanations are listed below. **Inheritance laws** Demigods are banned from inheriting thrones. You can use whatever excuse for these laws. The easiest would be that only mortals can rule over mortals. **Demigods are strong but unsuitable to be rulers** Since ancient times it was known that demigods are exceptionally strong but they are emotionally unstable and prone to self-destructing behaviours. The latter makes them unsuitable for holding positions of political power. Hence, while being welcomed by many rulers as generals and advisors they are unable to muster the support of the masses and nobility necessary to usurp a throne. **Demigods are seen as perpetual foreigners** Demigods may be strong like an ox and swift as thunder and lightning but no one invites an ox or thunder to rule their country. If mortals see demigods as someone alien and remote and incapable of relating to humans then mortals might not welcome demigod rulers. ]
[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/193358/edit). Closed 3 years ago. [Improve this question](/posts/193358/edit) There are plenty of famous interspecies couples throughout Sci fi and fantasy. Personally I like this trope because I am a sucker for science fiction that deals with the possibility that we can get along with each other, I am a sucker for romance, and I firmly love the idea of love conquering all. But as a writer and a world builder I want to try and figure out how to update this trope into something more...realistic. Because in fiction it is usually portrayed as a human and humanoid pairing up. But I am of the belief that the humanoid body plan will be a rarity meaning that most interspecies newlyweds might look something like this. Don’t they make a lovely couple? Now I do not believe that any difference in body-plan will be enough to dissuade all humans away from such courtships. I spend far too much time on the internet to ever believe anything *that* foolish. So the question is: **how would Interspecies couples work around alien body-plans to continue successful loving relationships?** [Answer] Any civilization which has the capability to travel interstellar distances at FTL speeds, also has other technology. This other technology can make inter-species romance easier. Some examples (from low-level to high-level): * Spacesuits and translators can be made so that the species can talk to each other * People can implant cybernetics or have their genes edited so that they can live in their partner's environment. For example, a human might have gills installed so they can live underwater or be genetically engineered to withstand higher temperatures. * Again using implants or gene-editing, people can adjust themselves so they can share in their partner's culture/lifestyle. For example, a human could get a cybernetic stomach capable of dissolving alien food proteins so they can share meals. Similarly, people could install "equipment" so they can have recreational sex with their partners * Using a neural-interface, people could remote-operate robot-bodies modeled after their partner's species. For example, a gas-cloud-space-whale alien could pilot a humanoid android around using what is essentially "full dive" technology or fully immersive VR if they want to hang out with their human partner * People could perform a brain- or consciousness-transplant into a cloned, brainless, body of their partner's species adapted for their use and effectively become "an alien". This also opens up the option of having natural, genetic children. * People could so thoroughly gene-mod themselves so that they're no longer their original species but a hybrid between the two to ensure genetic, romantic, and sexual compatibility. [Answer] Hold deep emotional talks, look deep into each other's dreamy eyes, and hold hands, tentacles, or pseudopods. That's what holds the **relationship** together. As to a physical relationship, that depends on how close the two species are, but there are humans in the real world who get sexual stimulation from all kinds of things. Having a sentient extraterrestrial involved is probably no barrier. [Answer] o.m. already gave a useful insight on the relationship side. If you are looking also at the physical part, don't forget that body plans are important only for a subset of all living creatures. A lot of sea creatures, for example, simply spread their gametes in the water, and let fate decide who mates who. Same goes with many anemophile plants, which spread their pollen in the wind without caring much about all the extra complications. This to say that body plan is not necessarily a problem. It is only if you require the two bodies to entangle during the mating act. Don't forget also that, as long as the two specimen can communicate, they can share with each other what is pleasurable or not. By the way, I explored a branch of this possibility in [this](https://worldbuilding.stackexchange.com/q/113527/30492) question. [Answer] I have a hard time imagining the interest in a physical relationship between such different species. Sexual desire involves a lot of hormones, pheromones, physical cues etc. which will be very different across species with no common ancestry. That said, there are all kinds of kinks, people marry their washing machines, and if the need arises, they will find a way. That will probably involve custom designed love toys, up to and including mechanical avatars & full body sensory suits to translate differing body plans. I'm very doubtful that they will ever be able to produce offspring, though, unless entirely constructed in a gene lab to create a new species to order with characteristics of both (or more). [Answer] **Internet.** People can love on the internet. People could fall in love writing letters! As compared to in-person interactions, distance communication makes body plan less relevant and sometimes body plan is not known. In some circumstances it may facilitate the interaction for one or more partners to simulate a physical body plan which is known to be pleasing to the other partner(s), sidestepping inherent and irrelevant biases which might otherwise complicate the relationship. This is true with the internet now and would be true for xenophiles. As it exists now the internet provides a platform that can host (an amazing and growing!) variety of standardized communications between partners. A future technology mediated interaction could be even more sophisticated. Love is not physical attraction. Distance communication facilitated with technology can make love possible that could never have been possible in person. ]
[Question] [ The safe word is "combined arms". This is extra-true for fantasy elements in a modern setting. Dragons and tengu are [helping with recon for their squads along with setting up mortars and sniper nests in hard-to-reach places](https://worldbuilding.stackexchange.com/a/180715/32097). The Foundation is also constantly switching between costly but hard-hitting mechanized troops (tanks, fighter jets, etc...) and smaller, nimbler organics. Similarly, I wanted to explain the presence of quarterstaffs, swords, and clubs as complementary to modern-age firearms and artillery. The only unique advantages, however, are their ammo (practically infinite), relative quietness, ease of manufacture, and tolerance to damage. **But when to use them?** They're still fighting at long distances and you probably don't want to risk getting closer. So, if I'm already involving genetically-engineered creatures, such as dragons, I might as well add something that's specifically designed to screw over firearms but can be more effectively dispatched with weapons like clubs, quarterstaffs, swords, spears, etc... I don't have any idea what such a creature would be, not even a clue. * They can be terminated with firearms, but it's less effective than using the aforementioned melee weapons. * The aforementioned melee weapons can damage the creatures badly enough to incapacitate or terminate them. * The creatures can attack and have an actual combat role in the enemies' ranks besides justifying medieval weapons. Knowing Worldbuilding, someone would probably have said that the answer is children. You don't want to waste your ammo and the quarterstaff gets the job done just as well. Well, now that kind of answer is invalid |) **So, how would this creature work?** [Answer] The first thought that occurs to me is a creature comprised of a body like a giant sponge—connections everywhere, so that poking a one-dimensional hole through it does virtually nothing; you'd need to cleave a 2D plane to damage it. As far as making such a thing anatomically-correct... well, we have amoebas and various other amorphous creatures, so why not the Sponge Monster? [Answer] I might go with an analogy to the Slow Blade and shields of Dune. Your animals' body structure is such that fast things like bullets zip right through & the tissues amorphously reconnect. Hammers & swords and such, however, separate the tissue long enough that surface effects preclude rebonding of the tissues. [Answer] Kevlar skin (you know, bullet-proof vests). A fiber so interconnected to it's other layers it distributes the force of the small projectile in a wider area, geometrically reducing the pounds/m^2 force and it's efficacy. Naturally, such creature wouldn't be natural, unless living in a enviroent where plants shoot you with spikes when you just try to survive. They could, however, be made so their skin is harvested. It would make bullet-proofing anything a lot cheaper if the critter were herbivorous. Also, at moon's gravity kevlar would be strong enough to anchor an orbital elevator. Naturally you would need an 'lunatic' amount ot it and ways to obtain it. You could also just add bullet-proof vests to your enemies. [Answer] You could go with a creature whose outer 'shell' resembles a Kevlar vest, able to stop projectiles (up to a certain calibre) due to its tensile strength and elasticity but vulnerable to piercing and blunt trauma. Maybe have it made from something akin to spider silk, with a layer of fat(?) as a shock absorber beneath it. [Answer] Make it so that it's a medium-sized creature (the size of a large dog perhaps), with a very thick shell/natural armor on its back (and perhaps even its legs and face). Very fast and vicious, very tough. I present to you the armadillo: [![enter image description here](https://i.stack.imgur.com/Sp3Bl.png)](https://i.stack.imgur.com/Sp3Bl.png) This funny-looking little guy has an armor which, depending on the angle at which it is shot at, can [deflect even modern bullets](https://www.independent.co.uk/news/world/americas/bulletproof-armadillo-puts-texas-man-in-hospital-after-shot-bounces-off-hard-shell-10432102.html). Your version will be much **fiercer and more bitey** and, as said, **the size of a large dog**; and their armor will scale accordingly. Perhaps it can be even thicker comparatively. You won't want to shoot at these guys from afar to avoid wasting bullets, and especially **if your allies are around** ([ready to be hit via **ricochet**](https://www.theguardian.com/us-news/2015/apr/14/georgia-man-kills-armadillo-wounds-mother-in-law-ricochet)). And if you are close enough, you better take out your melee weapon because this A-hole is going to come for your legs and groin, or even your throat. If you have a **sword**, on the other hand, you can try to cut him through **junctures** of the armor, or even try to strike **under his belly** where it's less armored. If it decides to curl up into a ball of armor, on the other hand, a **sledgehammer** might prove more useful. [Answer] Make it an extremely far-sighted sniper. If you're already incorporating genetically-engineered creatures in your own army, do the same for the enemy. Let them have some kind of natural sniper creature that has perfect eye sight over long distances, taking out your expensive tanks and troops with precision shots. Some of your own snipers try to take them out, of course, but they are routinely spottet before they can release the deadly shot. This kind of creature could be engineered specificly to be a sniper, or it could have evolved as a land dwelling predator with only flying creatures as prey. This creature could eject pebbles or other naturally occuring projectiles at high velocity to shoot the prey. It's eyes only need to see clearly over long distances, but they must quickly spot their prey and shoot it before it can fly away in order to survive. This creates a high evolutionary pressure to reliably spot living things (as opposed to plants moving in a breeze) in any environment. Once the prey is incapacitated, the creature can find it by smell and touch, removing the need to see clearly at short distances. This makes it a fearsome enemy in a warfare situation, where it can be equiped with special ammunition instead of pebbles and sticks. Specialized pioneer troups who sneak up on the creature and kill it with melee weapons might have a better chance of survival than highly trained snipers who have to move into its line of sight to take the creature out. [Answer] Have a creature with a certain level of non-Newtonian fluids as its dermal layer. Specifically, Sheer-Thickening fluids (like Oobleck). Slower moving items don't trigger the hardening effect of the fluid while faster and more energetic projectiles do. By basing its natural armor off from a known effect you can suspend disbelief a bit and go for slightly more story tailored reasons for it. ]