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[Question] [ Now, bear with me because I know very little of mycology. I just know that mushrooms taste good, and that fungi is very complex with lots of different uses. --- For my fantasy story, I want a society that knows the ins and outs of mycology. They grow food from mushrooms, make their medicines, from the them, and know which ones not to eat. I have said many times, if a society or civilization had the ability to do something that would benefit them, they would do it. So the question here is, how to make mushrooms a better and more reliable food source than wheat or other common crops used in Europe during this time? I'm open to making up a new kind of mushroom, but within reason. I'm mainly focusing on how to have mushroom growers common in in one area, or small kingdom. That means I can't have some super awesome mushroom outcompeting traditional crops everywhere. I understand that livestock mainly eat plants, so how do I make this a minimal factor? What setting would make it reasonable to have a medieval society whose main crop is mushrooms? How can I make it more effective than other crops? [Answer] [Fungi are not autotrophs like plants](https://en.wikipedia.org/wiki/Fungus#Characteristics). They don't just grow from nothing; they need something to eat themselves. Perhaps your character’s land is not suitable for growing efficient human-consumable crops, or they have not domesticated things like grains. Instead, they have rapidly growing plants that are inedible, like trees or fast-growing bamboo. That is domesticated as a feedstock for the fungi, which is essentially a way to transform the inedible wood into digestible food. In fact, [leafcutter ants](https://en.wikipedia.org/wiki/Leafcutter_ant) harvest leaves but can't digest them, using fungus as a food source. They cultivate the fungi but they *gather* the leafs to feed them. You could have small communities gather wild inetable fast-growing plants and cultivate fungi, in exactly the same way. # why not other (direct) crops Just as humans have grazed livestock on wild upen ranges, your characters can apply their direct efforts to the thing they eat and just use natural sources for food for that. But the next step, as populations get larger and populations move to new areas that don’t have such readily available fodder, is to apply efforts to cultivate the fodder as well. So now humans grow domesticated crops for staw to feed livestock, your characters can move toward cultivating fodder for the fungi. But originally they started by taking care of the fungi only. The lack of cerial grains, fruit, etc. could simply be that there wern’t any available for domestication there. Or, the climate or geology is not good for such farming. # why not animals Animals like [ruminants](https://en.wikipedia.org/wiki/Ruminant) use the same principle: they can eat plants that we can't, such as abundant prariegrass. In fact, such animals probably go with the folage. So why not eat animals? The simple answer is that no suitable domesticatable animal was available. Sure, with the abundant primary fodder occurring naturally, we suppose that the rest of the food chain would follow. But maybe they are absent for other reasons, like being extinct from the area due to climactic events (the grass holed up as seeds for a prolonged drought; the animals dependant on the grass died; the grass came back with the rain), or the plant life developed a toxin or inetable structure recently and animals have yet to exploit it. I like turning the problem around: lack of large animals is why humans were able to settle there, while previous megafauna kept that niche closed to us. Or, what animals exist there are simply not good for domestication. Now they are pests, not livestock. # what do you mean why not animals We are looking from our own culture. They might look at us and say “why do they raise cattle instead of fungi?” The efficiency of conversion of feedstock to human-etable food is presumably *much* higher for fungi! So, it has real advantages. ]
[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. A large solar flare event ignites the atmosphere of Earth, but luckily, humans have been preparing for an event like this for some time. We have a fairly large shelter around 2.2 kilometers underground. Energy is no problem, as we have built heat wells where they bring up heat into a controlled area, and we then run water over a heated cathode to spin a steam turbine. --- Assumptions about the environment and living conditions: 1. No materials can be retrieved from surface. 2. They are alone in their venture to survive: no divine intervention, no magic. 3. They need a sizable amount of water for their needs, and for vertical hydroponic farming. 4. The shelter accommodates up to 1000 people at a time. Assuming that each person drinks half a gallon a day, that will average out to 500 gallons for people, plus that for the farm. I would prefer for the colonists to have a liberal amount: enough for baths or other luxuries. **How do I explain how these survivors get water?** [Answer] Given that they're 2.2 kilometers underground, it looks like they can take advantage of [the water table](https://en.wikipedia.org/wiki/Water_table), the place where rocks are saturated with stored [groundwater](https://en.wikipedia.org/wiki/Groundwater). The water table often holds [aquifers](https://en.wikipedia.org/wiki/Aquifer), which can be accessed with only a bit of drilling. Is groundwater accessible 2.2 kilometers down? Well, they're certainly below the water table. I've found [a map of the water table depth of Wisconsin](http://dnr.wi.gov/topic/landscapes/documents/StateMaps/Map_S15_WaterTable_Depth.pdf) (chosen at random), and it shows that the water table is seldom more than 50 feet below the surface: [![](https://i.stack.imgur.com/hYe1u.png)](https://i.stack.imgur.com/hYe1u.png) It is important to note that the water table doesn't mark the area where the water is stored; it simple marks the highest point of stored groundwater. We do have a problem, though: How deep does groundwater go? 2.2 kilometers is pretty far down, relative to some sources of groundwater. For a good survey on aquifer depth, I chose [this report](http://www.cctexas.com/Assets/Departments/Water/Files/TWDB%20Aquifer%20Report.pdf) (Ashworth & Hopkins (1995)), a summary of various studies of aquifers in Texas. They identified nine major aquifers in the state. Here they are, along with the estimated water depth. * Ogallala: 600 feet * Gulf Coast: 3,200 feet * Edwards: 600 feet * Carrizo-Wilcox: 3,000 feet * Trinity: 900 feet * Edwards-Trinity: 800 feet * Seymour: 360 feet * Hueco-Mesilla Bolson: 9,000 feet (Hueco), 2,000 feet (Mesilla) * Cenozoic Pecos Alluvium: 1,500 feet 2.2 kilometers is about 7,200 feet, so most of these aquifers wouldn't be deep enough. Even the lower depths of some of the large ones contain dissolved solid minerals, that could be hazardous to human health. The USGS National Water-Quality Assessment (NAWQA) Program has [a variety of maps](http://water.usgs.gov/nawqa/digmap.html) and data detailing water quality nationwide. Various sources of terror for groundwater include * Nitrate * Chloride * Miscellaneous "dissolved solids" * Mercury * Phosphorous * Atrazine * More miscellaneous pesticides The water quality can vary by region. For example, [this map of nitrate concentration in the High Plains](http://water.usgs.gov/nawqa/home_maps/figure_4-5.html) (from [(Gurdak et al. (2009)](http://pubs.usgs.gov/circ/1337/)) varies widely, do to agricultural use and other sources. Location is everything when it comes to water quality. [![](https://i.stack.imgur.com/nlR79.png)](https://i.stack.imgur.com/nlR79.png) A nationwide map of aquifers can be found [here](http://water.usgs.gov/ogw/aquifer/USAaquiferMAP11_17.pdf). There's one last thing we have to address: How will these people access the groundwater? I would wager that they have decent drilling equipment, if they're that far down, so digging a well system (vertical or horizontal) shouldn't be too hard. [Answer] Some glacial meltwater can be found trapped in aquifers that are now continental shelves under the ocean, which while not as convenient could be accessed through horizontal drilling. You could also drain many aquifers by drilling "up" to the water table from your underground lair, although the details of either plan depend a lot on where the colony actually is. If they are ambitious enough and have the technical know how to do so, they may consider the theory that a vast amount of water is thought to be trapped in the Earth's mantle. This water was in the initial clouds of debris that formed the Earth, and is renewed by oceanic water being subducted into the mantle as part of plate tectonics. Some theories suggest that there could be a much as 3X the water in the Earth's oceans down there, trapped as molecules inside mineral crystals. "How" they could access water trapped in the mantle is a question for the reader.... [Answer] There is lots of water available underground. As Thucydides pointed out, most water tables are 10-100 ft below ground. Perhaps a bigger question is, how do you keep the water out of your structure? At 7000 ft of depth there will be thousands of psi pressure on any groundwater or petroleum, and it will find cracks and be pushed toward the void of an underground base. The tunnel into the structure will penetrate lots of strata that are water-bearing, and those would need to well sealed and/or continuously pump water out. Geology matters in all of this too. Coal mines are in sedimentary geology, and have lots of water bearing layers around them, so they must be actively pumped. If you're in igneous rock, like a gold or diamond mine, you'll have less, but still substantial seepage. [Answer] As an addition to all the other answers: they don't need new water. Yes it would be much more convenient, but the ISS is currently only importing abut 5% (no source because vague memory) of its water need, the rest is recycled. Given that, we can easily assume that they can survive on very little extra water for a long long time, meaning that a very very negligible income from some reservoir could suffice for thousands of people. ]
[Question] [ Using early 21st century technology how do I design a katana that can only be wielded by its owner and also to execute a special attack? In my story the surviving samurai still practice bushido (code of conduct) and they will be trained on how to swing the special katana. This katana is customised according to each individual and the razor sharp blade will turn into rubber if either not wielded by owner or switched to training mode. The user can also execute a special attack using the special katana called "vacuum slicer" by moving the blade quickly enough to generate a sonic boom that can cause significant damage to the opponent/enemy. My question is how can I produce a sonic boom using this special katana? [Answer] A sonic 'boom' depends on the velocity of a projectile through the air - it needs to travel faster than sound. A whip crack is an example of a small sonic boom and there lies your problem. A sonic boom that causes damage has to be produced by displacing a very large volume of air. Your blade isn't going to do that - no matter how fast it is wielded. Maybe you could cause temporary damage to someone's hearing by producing the sound near to their ear, but if you do that with a sharp blade then you've probably followed through and sliced through their shoulder to a considerable depth. This would sever a number of [vital blood vessels](http://goo.gl/4JK1Av) thus causing death within moments. > > *The cracking sound a bullwhip makes when properly wielded is, in fact, a small sonic boom. The end of the whip, known as the "cracker", > moves faster than the speed of sound, thus creating a sonic boom. The > whip is probably the first human invention to break the sound > barrier.* > > > Sonic boom - Wikipedia, the free encyclopedia > > > <https://en.wikipedia.org/wiki/Sonic_boom> > > > [Answer] As chasly mentioned, a sonic boom is caused when something breaks the sound barrier. The speed of sound on Earth is approximately `340 m/s`, so your katana will have to be going that fast in order to 'boom'. You could strap it to a fighter jet to achieve those speeds, but I assume you want to do this the old-fashioned way, and accelerate it with pure human strength. Let's assume the samurai winds all the way up for this strike, and thrusts the katana straight forward as far as it'll go. At the absolute maximum, assuming he doesn't jump, I'd say we can get the length of two legs, two bodies, and two arms(reaching all the way back to reaching all the way forward). I found the average height of a human to be 175cm, so cut off the head (like the samurai do) and you've got about 145cm. The average arm length is 65. So $145 \; cm \times 2 + 65 \; cm \times 2 = 420 \; cm = 4.20 \; m$ That is the distance the katana will be travelling. Using the equation `v=at` (v is change in velocity, a is acceleration, t is time), and knowing we want to get to the speed of sound, we get $v = a \times t\\ 340m/s = a \times t$ Plugging this and our distance into the equation $x=1/2\,a\, t^2$, we get $4.2\;m = 1/2 \times a \times t \times t \\ 4.2\;m = 1/2 \times 340 \;m/s \times t \\ 4.2\;m = 170\;m/s \times t\\ 4.2\;m = 170 \;m/s = t\\ t = 0.0247s$ That means your samurai has about 2 and a half milliseconds to begin and end their strike in order to achieve the desired velocity in the given distance. They could do it faster, but this is the absolute longest it can take. Plugging this value of t back into the first equation, we get $340\;m/s = a \* 0.0247s\\ 340\;m/s \; / \; 0.0247 \;s = a\\ a = 13765\;m/s^2$ And I have no idea how to get that much acceleration. Since this is the maximum distance you have to accelerate, and probably the fastest way you can move a katana (not to mention a thrust is going to have less air resistance, which was not factored into this answer), I'm going to say it's effectively impossible using anything close to a katana and samurai. You could probably just fire it out of a really big gun though. [Answer] You would need a **fake** katana - something more than a real katana. "Only the owner can wield it" is relatively easy, even if much depends on who you're going to fool and what exactly is meant by "wield". Recognizing the owner is the easy part: fingerprint (or palmprint) we already have, and we are not very far from fast and reliable DNA checks. Deactivating the sonic effect is also easy, since it **cannot** be obtained through blade motion imparted from the outside - no swordsman can move the blade at the required ~333 m/s. So you need to get it through some trick, i.e. technology and a energy source hidden in the blade, or more likely in the handle. Therefore, simply turn off the energy source, and no sonic boom. Making it impossible to wield the weapon as a katana is difficult, though. The two options I see are: * fake blade. It's actually two blade slices with a middle dull third slice running lengthwise. This has two purposes: until the real owner strikes, the middle blade is extracted, and the blade edge is dull. At the right moment an electromagnet brings the third blade in, and the two outer blades together, resulting in a single, sharp blade. The cutting edge will not be as tough as a real katana, but the air displacement will be enough to get you the sonic bang - actually a very loud "*thwack*". Also, the momentum of the middle blade being pushed backwards will force the rest of the katana *forward*; for a very brief moment, the blade can strike with many times the force of a human blow. As soon as the middle blade arrives in its rest position, its momentum expended, the blade will "brake", so we can pierce an armor, but can't cleave it in two. * blade used as sound convector. It's a single blade, but again electromagnetically, a powerful transversal wave is sent along the metal, effectively producing a whip crack at the far end. Of course, the blade is still a blade, so anyone can wield it. Against low technology or unprepared witnesses, other options are available. A low-voltage pulse at the right moment will be enough to make any *unworthy wielder* release the grip on the weapon (I'd be more comfortable if some contact on the back of the hand, or better yet the lower arm, was available. Otherwise I'd need large capacitors and the wielder would feel that the sword "bit" him). Several weak nerve agents can also be released with similar effects, but the wielder would have a numb hand and arm for up to several hours afterwards. In both cases, the witness report can be prevented by increasing the effect past the lethal threshold - dead men tell no tales. And in both cases, a *gloved* wielder would be a problem. Another possibility would be to have the handle (which is cylindrical) made up of several joined sections. To render the katana inoperable, we quickly spin whatever section pressure is applied on. The katana would "twist" in the wielder's grip, spoiling the strike. At worst, it would be like trying to hold a drill by the bit. Or the handle could subtly rotate a few degrees, making the wielder doubt his own senses and fruitlessly try to straighten his grip :-) ]
[Question] [ My world has a very peculiar low forbidding people from ciphering information. The penalty for such a thing is very very high. In this world everything should be seen and understood by anyone. It's a world of total openness. It's different from [this question](https://worldbuilding.stackexchange.com/questions/20730/what-would-a-society-without-cryptography-look-like) because it's not forbidden by the lack of knowledge but by some government. This obviously grant the possibility of breaking the law by ciphering information. * What would this society look like? Related questions: * [Could quantum computers break any code?](https://physics.stackexchange.com/questions/194334/could-quantum-computers-break-any-code) [Answer] **Well as a given** people will still have cryptography. To avoid punishment messages will be hidden using code words and the like, within larger messages that would appear to be about something else. Even if law enforcement had strong suspicion that a message contained a secret message, proving it would be difficult, and maintaining plausible deniability would be easy. Cryptography would have to be done such that it isn't definitely apparent as cryptography. This still isn't that significant, unless the legal system suddenly lowers the standards for a shadow of a doubt quite a lot, proving something is coded when it is intended to not appear to be would be nigh impossible. Cryptography would be pretty similar it would just be slightly inconvenienced. **EDIT:** What I mentioned is technically stenography not cryptography, anyway stenography will become widespread partially replacing cryptography. [Answer] There are real-world examples for what you have in mind. Take France, circa 1995. That's just 22 years ago now. The following is a summary from 1999, [courtesy of The Register](https://www.theregister.co.uk/1999/01/15/france_to_end_severe_encryption/). > > Until 1996 anyone wishing to encrypt any document had to first receive an official sanction or risk fines from F6000 to F500,000 (\$1000 to \$89,300) and a 2-6 month jail term. Right now, apart from a handful of exemptions, any unauthorised use of encryption software is illegal. Encryption software can be used by anyone, but only if it's very easy to break. > > > (In current terms, the fines ranged from €914 to €76,224, not adjusted for inflation and based on the exchange rate of [6.55957 franc per euro](https://en.wikipedia.org/wiki/French_franc#Euro_exchange).) In a society where **encryption,** or even just encryption that's strong enough to make a significant difference, **exists but is illegal to use,** it's very hard to protect digital information that is in transit. This means that information that we might readily send over the Internet encrypted might need to be delivered in person, perhaps by a trusted courier, to prevent it from being intercepted. If your society also prohibits the use of **digital signatures** and similar schemes, you also have a hard time *proving or confirming the authenticity of information* that has been transmitted or stored electronically. This for example means that it is very difficult to enter into an agreement electronically, because whatever is being transmitted between the parties could be tampered with and nobody would be able to prove that what was finally agreed to was what was *intended* to be agreed to. If your society also prohibits the use of things like **hash functions** then you have a big job in defining exactly where to draw the line. A hash function, in somewhat simple terms, is a mathematical function that accepts an input of arbitrary length, and outputs a value, typically of fixed length, which depends only on the input data. However, many functions with legitimate non-cryptographic uses, such as [cyclic redundancy check](https://en.wikipedia.org/wiki/Cyclic_redundancy_check) (CRC) and [forward error correction](https://en.wikipedia.org/wiki/Forward_error_correction) (FEC) codes can also meet such a definition. You have also pretty much outlawed every conceivable secure password verification scheme, because in order to be secure, you typically store only the output of a hash function given the password as input. (Before someone takes the preceding sentence and homebrews their own password storage: there are many, many, *many* nuances to this. For example, a plain cryptographic hash of a password is almost never secure enough against reasonable adversaries. Like all other cryptography, don't invent your own.) **This boils down to** that it is very difficult to securely store or transmit information or agree to anything, except in person. * Web shops and other forms of mail order exist, but electronic payment via tokens that need to be kept secret (such as credit card numbers and CVVs) is much more involved and might not exist. * Knowing who sent an electronic message is nearly impossible, as is knowing that it has not been tampered with. * For any kind of sensitive information, in-person delivery is likely to be preferred over any remote means of delivery. However, I disagree with [o.m.'s statement](https://worldbuilding.stackexchange.com/a/20767/29) that for example cell phones would be unavailable. There are plenty of precedents for technology being available in controlled products, such as cellphones, which is not available in "raw" form. For example, even if you had the technical expertise, it's unlikely that you'd be allowed to build a cell phone yourself from scratch and use it with a random cell phone network, because a cell phone operates in frequency bands which are restricted to type-approved equipment, and getting type approval can easily require you to jump through any number of hoops. One such hoop could conceivably be installing a government-mandated back door to the encryption, or maybe the cell phone network requires that you use weak cryptography enabling the government to eavesdrop. (In GSM, [A5/1](https://en.wikipedia.org/wiki/A5/1) and [A5/2](https://en.wikipedia.org/wiki/A5/2) are the real things, and both have been successfully broken.) Broadly speaking, the only part of the radio spectrum where prior type approval is not required is that allocated to [amateur radio](https://en.wikipedia.org/wiki/Amateur_radio), where [encryption is prohibited](https://en.wikipedia.org/wiki/Amateur_radio#Modes_of_communication). And of course, in the words of Philip R. Zimmermann, the inventor of PGP, in [volume 1 of the PGP User's Guide](https://www.gsp.com/support/virtual/email/pgp/docs/pgpdoc1.txt), the below being from the copy for version 2.6.2 released in October 1994, > > If privacy is outlawed, only outlaws will have privacy. Intelligence > agencies have access to good cryptographic technology. So do the big > arms and drug traffickers. So do defense contractors, oil companies, > and other corporate giants. But ordinary people and grassroots > political organizations mostly have not had access to affordable > "military grade" public-key cryptographic technology. Until now. > > > People who are already violating the law tend to either not care if their communications are intercepted, or not care about breaking one more law. Laws prohibiting cryptography won't stop them from using cryptographic tools if they want to, but those laws will prevent generally law-abiding citizens from using cryptographic tools to protect the privacy and integrity of their data. [Answer] * No internet shops, because there is no online payment system. * The web doesn't work, anyway, because pishing and spamming drowns out all legitimate content. Unless the lack of payment systems makes spamming unattractive. * No cellphones, either, because phones can't authenticate themselves to the towers. Landline phone or CB radio. * Many people are employed as couriers, carrying confidential information as printout in briefcases. The world might look a lot like 40s or 50s science fiction. [Answer] 1. *Mnemonic techniques will become very popular.* Assuming that encryption is absolutely forbidden, and that enforcement is both reliable and severe, there will be next to no way of concealing electronic data. So when absolutely necessary, people will view sensitive media very quickly, and then memorize their contents. Futhermore, an individual with a great deal of information stored inside their head will be able to avoid people guessing their goals, schedule, etc. by reading their web searches. 2. *Offline networks will be ubiquitous.* Because scientific computation and corporate development is still necessary, virtually every company will have extensive offline servers for development purposes. These will be heavily secured, and password-protected (not the same as encryption, I think). If someone grabs the hard drives, they can still get the data, because encryption is illegal. Of course, maybe passwords are too, but that changes little. 3. *As mentioned in other answers, physical documents will be common.* The same principle as offline servers. 4. *Most people who have not mastered mnemonics will also have offline data storage.* In fact, people might buy data (i.e. an encyclopedia, tax software) at physical stores, and physically transport it to their devices. 5. *There will be lots of "Max Headroom" incidents (<https://en.wikipedia.org/wiki/Max_Headroom_broadcast_signal_intrusion>.)* To compensate for this, media may be streamed online (although advertisers or trolls may frequently intrude). Another possibility is that broadcasters might transmit a program on many bands simultaneously, so that even such incidents are unlikely to disrupt all channels. ]
[Question] [ This question deals with the magic explained in [this question](https://worldbuilding.stackexchange.com/questions/13393/magic-that-alters-living-cells-growing-cities-out-of-trees). It is also explained below. > > In my fantasy novel, magic is a natural part of the world. It is not some mystical force shrouded in mystery, but rather backed by science (though only I, the author, know all of it's workings). > > > In my world, magic is a force that by its nature changes living cells. It is similar to radiation, but different in the respect that it changes what the cell does, usually in a beneficial way. For example, if the cells of an eye were exposed to magic, the magic might make the eye also see infrared light. > > > There are those in my world who can control the change worked by the magic. (They can force the magic to make the eye see infrared light. They can also use magic to make that same eye go blind.) > > > **Question:** I've already ascertained that magic-wielders would be able to grow trees into nearly any shape they wanted, including houses (see the linked question). What I am now curious about, is how the magic-wielders would go about making 'windows' in those tree houses. I am not certain how a tree could be altered to produce something relatively small, thin, and transparent, and yet sturdy enough to keep rain and cold out, and heat in. Currently, I've gotten as far as some sort of transparent leaf, but aside from not being sure if a leaf would work grown over a gap in the trunk, I'm not sure if it can be made transparent in the first place. **How could a tree be altered to grow something functionally similar to a window?** I don't necessarily need the window to be open-able, though that would be a nice side-benefit if possible. **Note for clarification:** This question cannot be answered simply by 'it's magic!' The magic cannot do *anything*. It can *alter* living cells to do things they normally wouldn't, but are still possible within the natural world. [Answer] I'm assuming that the magic of this world allows the magicians to endow a tree with any capability they desire. **Transparency** Have the tree collect silicon from the soil and oxygen from the atmosphere. Move the dissolved silicon and oxygen into a special pocket in the trunk of the tree where cells similar in function to animal [osteocytes](https://en.wikipedia.org/wiki/Osteocyte) will incorporate the silicon and oxygen into a thin matrix resembling bone. While making the matrix, the osteocytes could easily include voids in the matrix to increase its insulation power but at the expense of transparency. (You might be able to handwave the size of the voids to be small enough so they don't interact with light passing through.) After the matrix is complete, the tree peels back the bark and phloem to expose the silicon window. This should be extremely resilient as quartz melts at around 1700°C. Basically, you're growing miniature [geodes](https://en.wikipedia.org/wiki/Geode) within the bark of a tree. **Keep it clean** As an added bonus, have the tree grow a [superhydrophobic](https://en.wikipedia.org/wiki/Lotus_effect) layer on the outside of the window. No cleaning required and definitely waterproof. **Open and close** Venus Flytraps are well known for closing quickly when a fly lands on their leaves. A similar mechanism could be used to open or close the window. [Answer] You might be able to have the tree construct something like [nanocellulose](http://www.extremetech.com/extreme/134910-nanocellulose-a-cheap-conductive-stronger-than-kevlar-wonder-material-made-from-wood-pulp). A sufficiently skilled person might be able to get a tree to produce [cellophane](https://en.wikipedia.org/wiki/Cellophane#Production) as well, since cellophane is produced from cellulose. Or, if perfectly transparent windows aren't all that important, a thin, brittle sheet of dried sap might do. There might be some assembly required after the fact: support structures to remove that had been necessary during construction, for example. Like a sheet of cellulose that had been grown for the express purpose of giving the tree sap something to hold onto with while it dried. Or, in the case of cellophane, you might need to have knobs around the windows to attach the extruded cellophane to afterward. [Answer] This already exists in our world. Some plants have [fenestrate leaves](https://en.wikipedia.org/wiki/Fenestration_%28botany%29). [From Latin *fenestratus*, past participle of *fenestrare*: to furnish with openings and windows.] Thos plants have leaves pierced with small holes or window like openings or with hyaline areas so thinned as to be translucent or transparent. Examples * [Two fenestrate plants](http://www.cactus-art.biz/note-book/Dictionary/Dictionary_F/dictionary_fenestrate.htm) (Haworthia and Lithops) with their translucent tissues. * [Lunaria](http://www.shutterstock.com/pic-4754983/stock-photo-the-plant-lunaria-annua-agaist-white-background.html) with its translucent seed-pods [Answer] There are transparent structures grown from living cells. The cornea of the eye, in particular. Is the problem making it thick enough and still transparent? A non-living deposit made by living organisms are possible, such as seashells and other *tests*. In particular, look at the material used by [*diatoms*](https://www.wikipedia.org/wiki/Diatom#General_biology) and [*forams*](https://www.wikipedia.org/wiki/Foraminifera#Tests) > > Diatom cells are contained within a unique silica cell wall comprising two separate valves (or shells). The biogenic silica that the cell wall is composed of is synthesised intracellularly by the polymerisation of silicic acid monomers > > > Silicoloculinina are *glass forams*, making a test out of silica. The mechanism for making the shell is different (inside the cell space vs. Outside) so looking at both glass forams and diatoms for examples will give lots of ideas. It seems that depositing silica is something that cells **can do** and have developed multiple times independently. I suppose *we* could create such a thing using bio-engineering, in the foreseeable future. [Answer] I couildn't think of anything like that. That was both strong and see-through, though I liked both of ryepdx suggestions. Alternatively, to function similar to a window, a hole could be left in the tree and a leaf/flower petal is grown to cover the hole and it is able automatically open during the day and closes both at night and when it rains. Ofcourse this would mean that if you wanted sunlight in then you would also allow the wind in. Also probably wouldn't work that well during the winter. Even though it is technicly impractical, I liked the idea of having something similar to an automatic curtain/shutter. Mixing this with another idea like ryepdx would hopefully fill out any problems. ]
[Question] [ "Magic" is not declared as such, but there is an energy that comes from every object, and even some things that are not physical, like a gust of wind. Some call it the entity's spirit, or even its soul. Mages can feel them, but they can't be seen. Mages are people who can connect their own energy, their own soul, to the soul of others. When they do this they can influence the entity's soul, especially if their soul is much "firmer." Put another way, mages need to be very strong-willed and have great sense of self or they may find their own soul being manipulated by the other. However, just because you can change something's soul doesn't mean you can change what it *is*. In fact, you can't directly influence much of anything. A fire, for instance. Its soul might be one of consuming, greed, and of passion. A mage may connect his soul and share his compassion, contentment, and patience. The outsider may see the fire slow, and maybe even start shrinking if it is able too. To the outsider, it may look like the mage put out the fire eventually. In reality, if the wind were too strong, the fire still may not have a choice and it may still grow and consume everything. The danger of connecting to a soul that is simply too strong, like that of Earth itself, is great. The mages own soul is put in danger. But surely the Earth's soul has some qualities that would actually be helpful to a mage? Exactly what kind of danger might exist from connecting to a soul that is simply much stronger? The problem I have is that you shouldn't be able to make yourself "better" (*in society's, or your own, view*) by just lightly absorbing someone/something else's qualities. I'm having trouble coming up with why your own individuality is so important that it is simply always a bad idea to let anything change yourself. *The goal is to provide a solution that "makes sense" and would be enough of a danger where mages would not try it unless they are either very stupid or incredibly desperate. Simply "losing your soul" has implications which I don't want - though death itself may occur.* [Answer] You propose two different questions I will attempt to answer. > > Exactly what kind of danger might exist from connecting to a soul that is simply much stronger? > > > The main danger I see is becoming lost in the flow of energy/essence/soul/whathaveyou. For comparison purposes, let's let one hundred people be represented by an equal number of pebbles all of unique shades of the color green, then scatter them all in a well-fertilized lawn. if you look at the whole, you just see green, and the individuals tend to disappear. If you try to find the pebble that represents you, you're going to be at it for a while. In fact, you may not find your pebble again because someone else, who had a similarly colored pebble, picked up yours by mistake. The lawn doesn't care which pebble was claimed by which person, and likely doesn't even notice there were pebbles in the first place. If everyone connected to the same soul, you might not find your way back to your own body. The number of people would be a factor in determining how easy it is to return, but so would the size of the soul you connected to. To return to the analogy above, if there was only one pebble in the lawn, you could look for it for a long time. > > I'm having trouble coming up with why your own individuality is so important that it is simply always a bad idea to let anything change yourself. > > > The ability to identify oneself as an individual is a critical part of one's mental health. According to [this self-growth website](http://www.selfgrowth.com/articles/5-reasons-your-individuality-is-important), your individuality allows you to 1. think outside the box, 2. resist peer pressure, 3. be an effective leader, 4. be happy, and 5. inspire others. If everyone who connected to a soul X, then everyone would take on the qualities of X and there would be that much less individuality among them. Conformity has its benefits, but individuality is what moves things forward. Of course, the individuals could be those mages who were sufficiently self-aware and confident in who they were to not need to connect to souls, except when they were curious to know what it felt to be, say, a squirrel. Mages who weren't sure of their own identity would try to surround themselves with the identities of everything and everyone around them, their own unique identity eventually becoming lost amid the clamor of the personalities they then represented. In short, insecure mages would belong to the common masses, while self-aware ones would lead the way into new frontiers. [Answer] "Good" and "Evil" are matters of perspective and scale, I don't see the distinction as being particularly relevant to the over all question. Under the mechanism describe, the risk is the same in connecting to any soul significantly greater than your own, being overwhelmed and losing your sense of self. It would be like pouring a cup of water into an ocean, and then trying the extract that exact same water back out. The ocean most likely doesn't care about my cup of water, or even notice whether it is present or not. If there is a degree of control over the depth of the link, then there is a potential that you could skim off some attribute of that which you connect with, without immersing yourself completely. Perhaps I experience a strong emotional upset and find myself unable to focus on a task, a light connection to the Earth might help to ground me and stabilize. A strong connection on the other hand may result in me becoming totally indifferent to everything and just sitting there until I waste away and die. There is also the question of does the other soul notice the connection, or even have awareness? If I were to reach out and connect with a small animal, I could very likely smother its soul with my own, and bring it totally under my control and direct it like a puppet. When I finish the task I wanted it for, I could withdraw and restore it to itself. But if my attention was elsewhere I might not notice that an ant had reached out and connected to me. If said ant lost itself in the depths of my being, there would be very little hope for it to break away again unless I noticed it and helped to restore it and sever the connection. Shifting the perspective around, if the Earth's spirit is not aware, it would be unable to help me recover if I lost myself to such a link. This is where the benevolence of the greater spirit comes into play, would it care about you enough to help restore your sense of self? [Answer] I would say, loss of self, strongly Connecting to a soul magnitudes larger could overwhelm the mage. Like the earth bumping into the sun, the sun wouldn't really notice but the earth would be gone and absorbed in a flash. Smaller but still large and strong souls, could drag the mage along like a leaf in the eddy of a boat, they will survive but it could be a wild ride for awhile. [Answer] I wouldn't see it as danger from connecting to a "good" soul (or that there are good souls or bad souls) I just see it as you described with the fire. Connect with the earth's soul and you may become as passive and immovable, and if overwhelmed, part of the earth itself. Same danger with any living thing (animals and such) where your soul might be taken over. (Wherewolves would be the result of mages having been taken over by wolves etc.. etc..) A river which dies the moment it "stops" running could see the mage die when linked if he stays still. There are so many ways to create associations, and on so many levels. I'd suggest for each element or object or animal you want to link your characters to; make a list of their most important attributes or characteristics and use those to represent the benefits, drawbacks, and dangers of the link. i.e: A healthy Forest: Life, Fertility, ecosystem easily influenced (weather/season/outside interference). A boulder: Impenetrable, Immovable, Impervious but also clueless to what takes place around it and very little sense of time on a small scale. etc... [Answer] If people were to share "desirable" traits with each other, the risk would be to society and progress because of a lack of diversity. Diversity is key to good decision making, good team work and innovation. It would be very tempting for everyone to make themselves into the same "super human". Also, from the description of your magic system, it sounds like you might want a lot of unique personality traits to deal with various situations. Some people would just not have the calmness required to calm that fire. Also, suppose it starts younger - mothers/teachers imprinting their "lazy","willful" children, stifling creativity and drive. [Answer] To make it *make sense*: * precice nomenclature * rules that apply at the lowest level In your question, you use the word *energy*. It means something in real-world physics, and understanding physics better has led to a true fundamental meaning (it's intamate with time). Using it in a new-age way doesn't mean anything, and coming up with something is the key to making it realistic. If rules are *teleological*, it seems intuative to a primitve culture. We are hard-wired as primates to understand each other socially, and imagining that the natural world "works" the same way is a first hypothesis. But people's motives ans moods and ultamately behavior is not fundamental. We still don't understand how the brain does it. To *understand* the universe means to describe laws at the simplest level, and those create higher-level emergent behavior. *Energy* is a primitive as it gets; "because it feels pretty" is not. Underlying laws should be simple and "dumb". Making value judgements is not going to be fundamental. Quantum mechanics doesn't know about the boundaries of macroscopic objects. We can't describe some special rule for whales because an atom doesn't know where a whale ends and the water begins, or that a particular collection of atoms *is* a whale. So, rules need to apply to the smallest things, and know only about context in the same level being described. There are exceptions that are appoximations of emergent behavior: quasi-particles apply emergent behavoir of a large system back to primitive level quantum field theory. Magic, as commonly understood, would need to be driven by human brains, or the minds of gods that work like ours. Why would weather, for example, act in the manner of primate social behavior? I don't have a good answer off hand, but here are some ideas: * The universe is a simulation, an abandoned game filled with the decendants of in-game characters. They have forgotten their proper techniques for directing the simulation, but still have some ability. * The universe is created by the observers, and some can influence it more than others. It relies on intuative pattern matching rather than doing calculus (like catching a ball), so (a) things that are more teleological are more controllable, and (b) it is a pre-scientific understanding and largely rule-of-thumb or just plain wrong. * gods exist, like the Greek gods, which are basically how you behave humans with superpowers to act. But that's not great for modeling phenomena itself rather than appealing an authority to apply superpowers: its the rain itself that's intellegent and only powerful enough to work within its own range of behavior as an actor. What *is* "weather" as an object, and why would it be intelligent? That's why it needs to be the mage's own understanding that drives it. ]
[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 6 years ago. [Improve this question](/posts/12912/edit) # Background An evil Nature Mage (named Erilius) resides in a tropical forest where he has abundant access to local life (of which all the flora and fauna except people can be controlled by him) and where he has survived for 10,000 years through a combination of magic and his innate ability to control the minds of the sentient native cat people (to be known in the future as Felinus). Note that Erilius is not human and is the last of a formerly benevolent humanoid race of sentient magic users who helped humanity by solving our lack of food problem. After humanity and the elves betrayed him and drove his race to extinction he fled across a great desert and built his tower in the Rainforest on the southern side of it. He vowed to one day get revenge and drive us all to extinction and has been keenly studying hundreds of thousands of scrolls and hoarding the knowledge of magic his people had achieved to keep it from humanity for the last 9,980 years of his 10,000 year life. He has finally succeeded in uniting the too numerous to count competing tribes of the Felinus and has amassed an army of 3 million warriors (he united the entire race under his banner). He invaded the vast but disunified southern provinces of the human kingdom of Erial and has totally destroyed the Royal Mage Corps headquarters in the southern provinces. The King (John the Wise) has amassed an army of 50,000 knights, 30,000 archers and 120,000 disorganized regular infantry armed with halberds, all types of sword, spears and pikes and 20 of the kingdoms most powerful mages (still weak compared to Erilius) and set out to meet him in battle on a great plain where the knights’ charge will be the most devastating. These soldiers are the combined allied forces of his kingdom and two other more northern human kingdoms. The elves, a magic-prone race are hesitant to get involved because they naively believe that Erilius is scared of them. John, not wanting to trust his kingdom and all of humanity to the off chance that the elves would set out in force to aid him, sends his 19 year old magic-proficient nephew named Aran Strongheart and a small team of 10 of the Knights of Mordavia (a fearsome and devout knighthood that is loyal to the king and “the ten gods” only) to kill the Mage. They plan to lure the wizard into the virtually lifeless mountain caves in the dead center the barren desert. The desert is full of giant magical worms resistant to the Mages persuasion power and will willingly devour him as quickly as they would out hero. The worms live underground in a massive tunnel system spanning an area under the desert as big as the continental U.S. On the trip to the location Aran uncovers a mythical magical sword know as the Flaming Sword of Türbrik. The legends portray that the owner of the sword will rule the entire world and will save his race from extinction (not to mention it has unlimited magical powers to create fire and control already existing fire). Word of this somehow reaches the ears of Erilius and he sends a group of thirty cat people, which our group destroys via a surprise attack from the flanks in an empty worm tunnel. They interrogate the sole surviving Felinus and discover that he uses the eagles as eyes in the skies. They release it and head for the center of the desert. About ten miles from their target. In a small hardy village of desert dwarves they discover a scroll informing Aran how to call (attract) all the worms in a ten mile area with a whistle. When they reach the single mountain situated in the direct center of the desert they find the wizard waiting for them. --- # Magical Rules Medieval tech level only Erilius the Mage has the following powers: * Control all living things (both flora and fauna) within a 100 foot radius. He can cause plants to grow at near infinite speed if the conditions required for its survival and growth are met (i.e. Enough water and nutrients are present and there is sunlight). * He has telekinesis * He has limited telepathy (e.g. Those trained well enough can block him from their minds) * He can fly up to 10 feet off the ground for a max of 1 ½ minutes. * He can temporarily (think 10 minutes) assume the form of any known animal * He can control rock and change it into any type of rock or mineral(think turning coal into diamond, granite into coal, or rock into iron)(kind of like the earth benders in Avatar The Last Airbender) --- Aran Strongheart our hero has the following powers: * He can fly like the Mage * He can use telekinesis within a 30 foot radius. * Use the Flaming Sword the Mage is after to make and control fire. * Resist mind attacks better than others. --- # Question: Aran blows the worm whistle and dozens of hungry worms 60 feet in length and 20 feet in girth burrow up from under the mountain. Aran realizes this may not have been the best idea. Now both our Mage and hero are stuck in a duel on the mountain. The Mage has his own sword and gets into a duel with Aran while the other knights try to hold back the worms which are crawling up the mountain with their extremely small legs. **How would both respective parties get away from this situation?** Aran and at least 3 of the ten knights need to get away and the Mage needs to get away with many minor injuries. Since the worms are somewhat resistant to the Mages mind control he can't simply order them to focus entirely on Aran and his fellow knights. # Linked [How to Defeat a Nature Mage](https://worldbuilding.stackexchange.com/questions/12801/how-to-defeat-a-nature-mage?noredirect=1#comment30348_12801) [Answer] This is going to be a LOT easier for Aran to get out of. Erilius is going to have to think fast to survive this encounter. > > [the sword] has unlimited magical powers to create fire and control already existing fire > > > A sword with 'unlimited ability to produce and control fire' has already won at everything forever, unless opposed by another 'unlimited' force, or is opposed by non-flammable golems whose melting point is higher than the heat of fire the sword can produce. The only challenge is making sure you do not immolate yourself in the process. I'm going to add another restriction on the sword and declare that it generates the fire around itself, rather than being capable of remote ignition, otherwise this is way too easy for Aran. Erilius needs to get out of here. As fast as possible. He is away from his domain of power, and is up against an unlimited supply of fire. We'll focus on his escape first. 1. powder the stone around your feet and use your TK to fling it at Aran. If he cannot change the stone into powder, then change the stone into something like sandstone, which ablates easily against his TK. This will buy him time while Aran gets the dirt out of his eyes. 2. Shapeshift into a Peregrine Falcon. You are on a mountain, dive off the side and GTFO. Put some physical mountain between you and Aran ASAP. A falcon can cover a lot of ground in 10 minutes, so he should be safe, assuming Aran doesn't do something stupid. Now for Aran. 1. When Erilius throws dirt at you, use telekinesis to push it away from you. Do NOT use fire, you may cause a dust explosion. 2. Immolate the worms. I don't care how tough they are, 'little legs' won't hold up against unlimited fire, and if they open their mouths, pour fire down their throats. If that fails to kill them for some bizarre reason, maintain the inferno around each worm until it suffocates (fire consumes oxygen, worms breathe oxygen). 3. Casually stroll home. If you want to make this harder...or make Erilius vs. Aran into a fair fight, you're going to need to restrain that sword. [Answer] I always thought it was a cop out, but you could go the old fashioned LOTR route and have giant magical eagles fly them to safetly. [Answer] Seeing as he is basically an Earth Bender he can just reform the stone around the feet of our hero's knight companions. The knights don't seem to be able to defend themselves against this kind of magic, but Aran might well be able to fight off the magic that is starting to surround him, especially with his telekinesis. After that Erilius can try to escape himself. In the mean time however he will have to defend against the magical flaming sword and the telekinesis attacks of the hero, which will surely lead to quite a few minor or even major injuries, just as asked by the OP. As Aran is a *hero* he will surely try to help his friends if he has to decide between following the Big Bad Guy and trying to safe his friends. This makes for an interesting plot point, because you can show how Aran has to decide which of the knights he wants to safe - the easiest way would be to cut off the feet and at the same time burn the wounds so that they wouldn't die because of the blood loss, but he can also try to work with his telekinesis and sword to just destroy the stone. Again, the method makes for an interesting story and the draining on Aran's energy will make his escape harder. Erilius on the other hand has to escape as fast as he can because he can't control the worms and the magical fire sword is a big problem in such a fight. He can try to fly away in the form of an animal and float around a bit to get ground between him and the hero. This should be easy seeing how the hero summoned the worms and if they cannot reach the tasty mage they probably won't pursue him very far. If they do he may have problems, but it shouldn't be too much of a problem for a skilled Earth Bender. Aran on the other hand has to make some morally difficult decisions about saving his friends and eventually hurting them, which makes their escape more difficult. After that he basically has to fight alone against the horde of magical worms he summoned to his position and is forced to stay on the ground with his potentially injured knight friends. Some of them will surely die, because even with a magical sword that will guarantee Aran's survival, he is still only one person and cannot potentially fight such a horde of magical worms alone. The knights should stay close to Aran, but not so close that they will be hurt by the sword. ]
[Question] [ I wanted to ask about the system described in the following scenario... A villain has built a system consisting of a telescope connected to a computer that runs some autonomous object recognition software. The villain's goal is to catalog all man-made satellites circling the earth, so that he can attack them from his secret base on the ground. This is a stationary (but can be relocated, if needed) system, located in some desolate area sufficiently far from artificial light sources (but not necessarily on a particularly high altitude). It passively monitors all objects that pass over it and can use multiple steps to gain more information about an object after it recognizes it as a man-made satellite. The steps would be something like this: 1. recognize the stars, planets, and the moon (so as to avoid cataloging these and for self-awareness of own location) 2. recognize airplanes based on the lights on them (so as to avoid cataloging them) 3. recognize objects that are not of type #1 or #2, i.e. something that is potentially a man-made satellite. These objects would be recognized by e.g. the object traversing (nearly)the same path in the sky at about the same time as once before. When the system recognizes an object as a potential satellite, it would beam some radiation or laser on it so as to make it briefly more visible on some wavelength. The sensors on the system would then record how it looks like (in the particular wavelength) so as to catalog it more definitely. The aim of the villain is to catalog the satellites of the country he considers his enemy. So this means that the system would have to be able to recognize satellites sufficiently well so as to differentiate what country they belong to. To some degree this would compare the found satellite to public data (such as is available for e.g. weather satellites). On another hand I am not yet sure if it would be possible to differentiate country X military satellites from country Y military satellites, when no photos or other data may be available on the military satellites. The questions I wanted to ask are: 1. Would something like this be feasible? 2. Approximately how large a telescope would the villain need? 3. Would the system have to be located in specific part of the world to be able to recognize polar orbit satellites? 4. Is there a way to make some far-away object more visible (in some particular wavelength) by e.g. shooting a laser at it? [Answer] There is an awful lot of that data publicly available, [NASA and the defense department](http://www.nasa.gov/mission_pages/station/news/orbital_debris.html#.VKVb-smWfik) are tracking over 500,000 different pieces of space junk orbiting the Earth. It is all cataloged as to size and most of the satellites are identified to at least who owns them, if not all of their capabilities. I also found this web site <https://www.space-track.org/auth/login> which appears to try and collect and share most of the data you are looking for. So I would say you have a better chance of collecting the data from sources here on Earth than taking the time to try and map the skies. Most satellites can detect EM emissions (that is how they communicate with the ground!) and Military Satellites have a much wider range of detection abilities. Unless the satellite is broadcasting it's information it would be very difficult for someone or something to identify who owns it by pictures, unless you have a large database of all known satellites. [Answer] I second bowlturner's comment, there would be no point because we already *know* about every satellite out there Even most spy satellites are pretty well documented by the laymen. Instead I wanted to add that no stationary system would be able to do much of interest. You could only see satellites that flow over that area. Since most satellites are geosynchronous, staying at roughly the same place their entire life, you would miss the vast majorities of satellites. Admittedly spy satellites, the most interesting ones to document, are not geosynchronous, but even those fly over a very specific ellipse, if your station does not happen to reside under the path of a satellite you won't see it. You could reposition, but you would have to reposition so often as to make the process very time consuming, and even then you could never be certain you say *all* the satellites. There is nothing you need to do to make satellites more visible, a more precise telescope would be far more useful then trying to shoot a laser or to 'light up' the satellite. In truth since satellites are so close to earth they aren't that hard to view visible. The more interesting task though would be to record what electromagnetic signals may be coming out of those satellites. Unfortunately you could only record signals from the satellites that come close to your stationary object, and most EM emissions are very tightly focused beams, it would be hard to detect the emissions. [Answer] You could shoot lasers at sats... but that will reveal your secret base. And might get you targeted for return fire/investigation (if it's your own country's satellite). Most of the time they take getting hit with a laser passively, except for noting when/where it's coming from (and use side-viewing cameras on those locations). AFAIK, there's no way to determine whose sat is whose, by just looking at them. Even if you could get a good view of them. Also, military satellites can move or change orbits, and often have the fuel capacity to make use of that capability (not a lot, nor often - but they aren't just static). <http://www.spacetoday.org/Satellites/YugoWarSats.html> <http://www.nationaldefensemagazine.org/ARCHIVE/2004/DECEMBER/Pages/AirForceMulling5928.aspx> -- Geostationary sats are detectable, when they occlude stars. So I disagree with some of the other answers. ]
[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 9 years ago. [Improve this question](/posts/410/edit) Planet elevation maps can be quite big, zooming in/out can be quite costly. I wonder if there is a ***most efficient*** data-structure used to store elevation maps such as quad-trees or any tree-based structure that will make appear details of the planet surface only when a certain level of details is required (and not before) with a fast access to the data. [Answer] A hierarchical triangulated irregular network (HTIN) is probably what you are after. A TIN consists of a delauny triangulation over a set of point samples which are distributed based on the frequency of the surface being modelled. Where the surface varies rapidly, the points are dense, and where the surface does not vary, the points are sparse. In a hierarchical TIN, the points and their triangulation incorporate an order of precedence and a spatial index so that sections of the triangulation can be extracted at specific levels of detail. [Answer] There are two common ways to store elevation data, the first is by point the second is by contour. Storing a selection of points suffers because you're limited by the granularity of your data, if you only hold an elevation each metre of surface area you have to interpolate the distance in between. You also end up with a lot of redundant data (after all large portions of land are effectively flat). If you look at almost any good mountaineering map you'll notice that height is not indicated by a sequence of dots in a grid. It's represented by contours, these lines (of varying size and shape circles encircle peaks and mountains. As you can imagine it's a lot more efficient to store a line of coordinates which are at the same height than every point on the globe. In terms of actual data structures I would suggest the following: ``` <contours> <contour height="123"> <point lng="53.2852" lat="-3.5788" /> <point lng="53.2952" lat="-3.5288" /> </contour> </contours> ``` When your application is passed a point it should determine which is the innermost contour it lies within (perhaps add a ParentContourID to help?). That will be the height of your point (or you can interpolate from the nearest two). ]
[Question] [ I'm working on a hard-sci-fi story where a scientist discovers microorganisms in our solar system with disastrous results. I was thinking about how any cross-contamination with an alien ecosystem would cause the organism to self-destruct in a similar manner to matter, anti-matter annihilation. I'm more inspired by science fiction works like War of the Worlds, The Andromeda Strain, Annihilation, etc., but I'm also interested in explaining how alien life could have evolved with novel-yet-similar mechanisms to life on Earth. Leading me to the whole L-sided vs D-sided amino acids and protein synthesis. So how would the organisms interact with each other? I was thinking all the cells would self-destruct leaving behind traces of organic material and a myriad of novel viruses. Any material, references, or input is always appreciated. [Answer] When amino acids/azucars/attibic molecules are supplied in the "wrong" direction 3 things can happen: 1. Let's take L and D-glucose as an example, in humans (and almost every organism for that matter) both L and D-glucose have a perceptible sweet taste but only D-glucose is efficiently usable, you see if we consume L-glucose simply nothing happens, it is not usable in the creps cycle nor in any anabolic metabolic pathway, even so there are isomerase that convert L-glucose into D-glucose that means that you can use some of the L-glucose but the production of enzymes spends energy and amino acids so it is very inefficient, this is an exception most of the sugars do not behave like glucose. 2. They do nothing, you see most receptors are stereospecific i.e. they only accept one configuration, for example methamphetamine has 2 configurations one is psychoactive the other is inert despite being chemically identical, simply many things in your chiral aliens would not be recognized by the enzymes and would just go in and out without any change, especially the amino acids which would not be recognized at all by the ribosomes. 3. They are toxic, remember what I said about most sugars not usually behaving as in example 1, well, what happens here is that your molecular if they can bind to enzymes, but this can not alter it so the enzyme is irreversibly blocked, so in the best case you lost a single enzyme perfectly functional and at worst you broke the entire molecular machinery of a mitochondrion, for example. The interaction of your bacteria will be moderated by these 3 possible reactions in different proportions, it is not impossible that you will kill all life on earth, but most likely the battery will die or nothing will happen at all. Finally, you never ask, but the only reason all life on earth is just an evolutionary whim and that is encoded in hyper conserved regions, nothing makes it impossible or even improbable that what you describe will happen, it is a 50 50 chance, but once an organism appears it will never change meaning. And no, a virus cannot infect a DNA counter-sense and most likely neither can a bacterium. [Answer] Darth Momin provided a decent answer, but you don't need to go into that much detail. Put simply, the organisms would be mildly toxic to each other in numerous ways, but it would prevent almost all infections from crossing over. Entities with inverse aminos wouldn't have an issue with normal interaction, or even touching. Sex might be a bad idea, and you wouldn't want to eat them. D-amino acids block the pathways that L-amino acids would use, decreasing bioavailability. D-aminos are actually fairly common in our environment, but bacteria in our soil preferentially breaks it down to free up nitrogen, thus reducing our exposure to it. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3960212/> ]
[Question] [ I have a planet that has no natural water bodies or sources. Is it feasible (assuming technology along the lines of the Earth Engines from "The Wandering Earth") to take asteroids from a belt/field and deliver water to this planet? Probably enough water to sustain a human population of 1 billion + agriculture. This also probably ties in to "what is the best way to transport water" and ice density. (I am new to this, please go easy on me) Edit: (clarification) Earth engines are giant engines pointed towards the sky in a large array that are used to move the Earth out of orbit and to a new system. [Answer] # Depends For base assumptions (Since you haven't mentioned the specs of your solar system), we are going to take our Solar System for a start. In case you are trying to mass mine water ice from asteroids in the Asteroid Belt, which is located between the orbits of Mars and Jupiter, you would be hard pressed to find water in the Asteroid Belt. It's a straight pain in the a\*\* to find enough water to provide water for a single spaceship. Based on this paper, there is only about [100-400 billion gallons](https://www.space.com/how-much-water-in-asteroids.html#:%7E:text=According%20to%20that%20estimate%2C%20there,spread%20among%20these%20space%20rocks.) of water in the asteroid belt. And thats not per asteroid, that's the **TOTAL AMOUNT** of water in the asteroid belt as a whole 400 billion gallons may seem grand enough. But only till you realize that the total amount of water on Earth is [326 quintillion gallons](https://www.phoenix.gov/waterservicessite/Documents/All%20the%20Water%20in%20the%20World.pdf). The asteroid belt contains about half the amount of water present in [Lake Huron](https://www.mlive.com/weather/2022/12/lake-michigan-lake-huron-lose-over-3-trillion-gallons-of-water-in-november.html#:%7E:text=Since%20Lake%20Michigan%20and%20Lake,800%20billion%20gallons%20of%20water.). And that means each asteroid would contain a tiny miniscule proportion of water in them. Of course there are exceptions like Ceres, that contain a lot of water. But as I said, on average, it is as hard to scavenge (yes, **scavenge**) water in the asteroid, as to move a truck by using fireworks. However, there is a lucky spot in the Solar system, that is rich and juicy (yes "juicy") with water- ~~Pluto's crib~~ **The Kuiper Belt** If your humans have access to the Kuiper Belt, they are **GODDAMN LUCKY**. Based on [this paper's](https://theconversation.com/water-water-everywhere-where-to-drink-in-the-solar-system-46153#:%7E:text=Comets%20and%20the%20Kuiper%20belt&text=They%20are%20mostly%20water%2Dice,masses%20of%20water%20out%20there.) estimates, if you could gather the entire mass of the water in the Kuiper Belt, you can gather as much as 5 EARTH MASSES worth of water. This would rival GJ 1214b (An ocean world with 8 Earth masses) in terms of water present. Your humans could send large mining probes (manned/unmanned), to mine out the asteroids/comets in the Kuiper Belt, to get a ton of water from each asteroid/comet. Since each comet (I am going to stop using "asteroid") is rich and juicy with water, your planet could easy get wet and drench to the brim with water quickly. Happy mining comets!!! [![enter image description here](https://i.stack.imgur.com/lDhqC.png)](https://i.stack.imgur.com/lDhqC.png) [Answer] You absolutely could. There's a lot of water in the asteroid belt. Most of it can be found in [Ceres](https://en.wikipedia.org/wiki/Ceres_(dwarf_planet))... it is estimated that Ceres may be as much as [25% water by mass](https://www.space.com/28776-nasa-dawn-ceres-russell-interview.html). Given that it weighs asbout 9x1020 kg, that gives you ~2.25x1020 kg (or ~50 billion *billion* gallons) of water which is a generous share for each of the billion consumers. That's small beans compared to Earth, which may as well be an ocean planet... Earth's seas have [five times that much water alone](https://en.wikipedia.org/wiki/Water_distribution_on_Earth), and water in the deeper layers of the planet could mass at least 10x that again. Your world might be a bit of a desert by comparison, but it at least wouldn't be dessicated. I'm not sure if you'd be able to form a natural water cycle, but if you kept the water in domes and tanks and so on you wouldn't have to worry about losses. Spare water might be parked in the form of ice at the [sun-planet L2 point](https://en.wikipedia.org/wiki/Lagrange_point). I do have to wonder why a billion people would live somewhere with no water, but its your setting and not mine! Now, moving even dwarf-planetary masses about is very far from trivial and neither is breaking them up for parts, but if you're handwaving in mechanisms capable of samely ejecting Earth from the Sun's gravity and driving it somewhere nice, then moving around something 10000 times smaller should be child's play. Completely dismantling Ceres and gently depositing it on the surface of a planet is left as an exercise to the reader, but again: if you can move the Earth then this sort of thing shouldn't present a significant challenge. If your local asteroid belt is a bit dessicated, you don't have to go as far as the Kuiper belt or Oort cloud (which are a *very* long way away, so transport times are likely to be quite extended, and *very* large, so exploring and harvesting them will inevitably be awkward and slow). Once you get past the [frost line](https://en.wikipedia.org/wiki/Frost_line_(astrophysics)) of your local planetary system, you should find a fair amount of water given that its elemental constituents are some of the [most abundant in the universe](https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements). Ceres is right on the edge of the Sun's frost line, so maybe in your setting such a convenient world isn't available, but gas giant moons are pretty packed with ice too. [Ganymede](https://en.wikipedia.org/wiki/Ganymede_(moon)) is heavier than Ceres by a considerable amount *and* it is less dense implying that it may be as much as 50% ice by mass. If breaking up something that big is too much of an engineering challenge then you may find that nature has done it for you in the form of something like [Saturn's rings](https://en.wikipedia.org/wiki/Rings_of_Saturn). This has less water than Ceres (about 1.5x1019 kg, but that's still 15 million tonnes of the stuff per person on your world) but it is mostly in the form of easily accessible lumps that may be many meters across for convenient collection. If you can shuffle moons around then bringing some ice moons to their [Roche limit](https://en.wikipedia.org/wiki/Roche_limit) by moving them into a close orbit around their parent and creating some new ring systems might be a good way to split them up for harvesting and transport. [Answer] ## Look Down, Not Up Planets are formed by the accretion of local elements. If your solar system has a significant amount of water in the asteroid belt, but not on the surface of an inner planet, it does not mean that your inner planet does not have water, but that the surface water has evaporated away over time. However, your primordial solar system would have had a relatively even mix of elements meaning that your planet should have similar amounts of subsurface water as you find in your asteroid belt. You just have to figure out how to mine and refine it. Depending on the tectonic nature of your world, this will look like one of 3 things. 1. The cheapest and most probable option is that the planet has subsurface oceans that you can tap into with technology similar to a modern oil or fracking rig. Any planet that ever was tectonically active will likely have significant subsurface oceans; so, by the time you have a permeant settlement of anywhere near 1 billion people, you'll have had plenty of time to explore and survey your desert world for these subsurface oceans. 2. The planet is not, and never has been tectonically active. Here, any rocks below the plant's surface will contain large amounts of primordial minerals rich in oxygen and hydrogen that have never seen the blast of solar radiation to strip the water away. These minerals will form steam when smelted. Because there is not techonomic activity, it means that the subsurface rock is not being naturally smelted and recycled; so, they will contain significant amounts primordial water producing elements even if no liquid water can be found. 3. Your people rely on a hybrid model. When your colony is first founded, you will likely not know where to find sub surface oceans, and as you expand, your demand may exceed what you can get from them requiring you to smelt rock in addition to your deep water mining. In this case, smelting rock will be less efficient, but still doable. ## Why this is better than asteroid mining Moving mass across interplanetary distances is extraordinarily expensive. Even if you found a giant asteroid made of pure water, moving the trillions of gallons of water your population will need across this distance, and lowering safely down into an atmosphere/gravity well without it all just melting away is an unimaginable cost. Doing that with modern technology would cost thousands if not 10s of thousands of dollars per gallon of water. In contrast, a gallon of water pumped from a deep subsurface ocean could be almost as cheap as water is today when pumped from Earth's own subsurface water reservoirs... though it could be a bit more expensive depending on what kinds of impurities you need to remove from it before its fit for consumption and/or agriculture. This puts the cost at somewhere between 5 and 8 orders of magnitude less energy per gallon than it takes to get your water from space on a world with Earth like gravity. The second option is of course more expensive because you have to heat rock to its melting point. Depending on what minerals are native to your planet, expect to need to heat up rocks or sand to 600-1200°C to get water out of them. This is of course going to be several times more expensive than mining a subsurface ocean, but it's still probably going to be about 3-5 orders of magnitude cheaper than importing your ice from space. ]
[Question] [ As title. What geographic features could cause a stable pocket of unmoving air? I'm envisioning some kind of shrine, sacred place, or untouched grotto, which due to terrain features or certain aspects of the environment, has a naturally occurring, local weather system. In this system, there is to be a localised area in which air becomes still. This should occur predictably, if it's impossible for it to occur permanently. What kind of geographic features, elements of the environment, or other factors, might cause such a place to exist, where no wind blows and the air is as still as possible? [Answer] ## Caves with underwater entries Some caves are isolated by a waterway, resulting in the air inside to be isolated, always at the same temperature and, if the water does not move, perfectly still. For the air to not escape through other cracks, the geology of the cave needs to be in such a fashion that it has little to no cracks. If the waterway falls dry for some time of the year, then the air inside will move for that duration, but otherwise be perfectly still. [Answer] **A Deep And Narrow Pit at High Latitude** To shelter a location from the wind, it needs to be lower than the surrounding terrain on all sides. If it is lower, then wind will tend to travel above the floor of the valley. This effect is most significant when the valley air is colder than the surrounding air. To create this temperature difference, one needs to reduce the amount of sunlight which reaches the floor of the pit. There are two effective ways of reducing the amount of sunlight which reaches the center of the pit. The first is to make the pit deeper while keeping the area constant. This makes it harder for sunlight to reach the bottom of the pit. With less sunlight, the pit will remain colder year round, making it more likely that outside winds will just blow over. The second is to place the pit at a high latitude. At high latitudes the maximum solar elevation angle can be lower than 30 degrees. If your pit's walls are almost cliffs, then at the bottom you can have a permanently shadowed area. This pocket will be much colder than the outside. Since cold air is denser than warm air, it will remain at the bottom of the pit and be stagnant. For this pit to be stable over a long period of time, your story would have to occur in a hot high latitude desert. This pit is a basin with no outlet and minimal sunlight. Unless rainfall and snowfall is extremely low, it will fill with water and become a lake. For a hot high latitude desert to exist, your planet needs to be much warmer and much drier than Earth. In essence, your planet's oceans need to have evaporated off into space long ago. The pit will likely be a refuge from the harsh conditions, having abundant slow growing vegetation adapted to life within the crater. For desert dwellers, it will be an alien environment completely unlike any other part of their world, well worth the descent down sheer walls. [Answer] For a large scale example, see the article on [Temperature inversion](https://en.wikipedia.org/wiki/Inversion_(meteorology)). A warm layer of air can trap a cold layer beneath it. If you are in a valley, this can trap your air. You can get a temperature inversion with natural weather conditions, but they can also be caused by a photochemical smog, which warms the upper atmosphere. The temperature invasion does not stop wind, but it can give a still lower layer. [Answer] **Bubble-Creating Lifeform whose bubbles harden after creation** Imagine a crab that builds a burrow, perhaps to lay its eggs in, and its secretions harden the walls. Separate secretions from the newborn (after devouring the parent of course) would let them out. This would be an anoxic environment. Micro-biology could probably do a similar thing, but it would have to be a very specific soil in order to maintain its shape instead of the bubble popping. Possibly the microbes need to maintain specific atmospheres for specific life stages. This could be done on larger scale with cooperatives like Portugese-man-of-war , or mats of bacteria or algae that had slow reproduction and multiple life stages. Or perhaps they receive energy from radiation that can penetrate the bubbles but direct exposure is dangerous , or perhaps they enjoy neutron-activated specific minerals but not the originals. In any case, "still pocket of air" is the same as "completely covered and sealed" because air always moves. ]
[Question] [ We can know what genes affect what outcomes by following the trail backwards, but can we predictively know what changes to what genes would result in completely different and previously unseen outcomes? For instance, we may know what gene causes blue eyes by having found it through testing, but do we know what human gene change would result in human sight extending into the ultraviolet, or some such other specific outcome? (note that this is a for instance and not the actual meat of the question). Or are we completely limited in our knowledge of what genes might cause what outcomes by examples in nature? The question goes to the idea of specifying "positive" evolution through gene editing (of both the host and the sex cells so that changes are inherited) rather than waiting for it to occur and then selecting it. [Answer] We are barely at the beginning of understanding the complex interaction between gene expression during the organism development. Until now any scientist who wanted to understand what a gene did, had to switch it off and try to understand what the consequences were on the organism, which is comparable to how a toddler interacts with toys: push buttons around until a causal correlation is built. Nowhere close to the engineer following the schematics to check that squeezing the nose will result in the teddy bear producing the sound of a laughter. For example I have recently read in the news that the black death in the middle age has left us with some diseases consequence of the genome bearing the plague resisting genes. Does it mean that we know what the consequences of being able to survive Covid19 will be? Of course, we just suspect that something will happen. [Answer] Of course we do. Sort of. Not much. Mostly not. More realistically, we have a vague idea of what we would *hope* to obtain by adding some specific extra genes. Most usually, the results are disappointing; but sometimes, rarely, we do indeed get what we wanted, or at least something which is not bad. Don't do this at home. Don't even *think* of doing it on humans. But yes we do know enough to practice it routinely. On plants. On fish. On other such organisms which are beneath our respect. You may have heard of the unexplainable fuss some mass media organizations have stirred in regard to [genetically modified organisms](https://en.wikipedia.org/wiki/Genetically_modified_organism). Those are perfectly normal organisms whose genomes have been altered rather directly, instead of the traditional methods of hybridization or induced mutations, followed by selection. The discipline of designing and applying direct changes to the genome of an organism with the goal of obtaining useful traits is called [genetic engineering](https://en.wikipedia.org/wiki/Genetic_engineering). There are literally millions of tons of genetically engineered organisms in the world. Examples: * [GloFish](https://en.wikipedia.org/wiki/GloFish)™ are artificially created [zebrafish](https://en.wikipedia.org/wiki/Zebrafish) *Danio rerio* or [tetras](https://en.wikipedia.org/wiki/Tetras) *Gymnocorymbus ternetzi* which have the attractive quality of fluorescing when illuminated with [blacklight](https://en.wikipedia.org/wiki/Blacklight), that is, ultraviolet, light. GloFish™ is a trademark of Spectrum Brands, Inc. The generic term is genetically engineered fluorescent fish. Fluorescent aquarium fish were created by Dr. Zhiyuan Gong at the National University of Singapore, originally by incorporating in a zebrafish embryo the gene which encodes the [green fluorescent protein](https://en.wikipedia.org/wiki/Green_fluorescent_protein). Nowadays you can buy zebrafish which fluoresce green, red, or orange, each line containing genes which encode for specific proteins. GloFish breed true, that is, a mother red-fluorescing zebrafish and a father red-fluorescing zebrafish will produce red-fluorescing little zebrafish. There is some limited evidence that wild-type female zebrafish prefer fluorescing males to the dull wild-type males. [![Fluorescent zebrafish fluorescing in the dark](https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Danio_rerio_GloFish-science_institute_aquaria_05.jpg/617px-Danio_rerio_GloFish-science_institute_aquaria_05.jpg)](https://commons.wikimedia.org/wiki/File:Danio_rerio_GloFish-science_institute_aquaria_05.jpg) *Fluorescent zebrafish fluorescing in the dark. Photograph by Karol Głąb, [available on Wikimedia](https://commons.wikimedia.org/wiki/File:Danio_rerio_GloFish-science_institute_aquaria_05.jpg) under the [GNU Free Documentation License](https://en.wikipedia.org/wiki/en:GNU_Free_Documentation_License).* * [Golden Rice](https://en.wikipedia.org/wiki/Golden_rice) is an artificially created variety or rice *Oryza sativa* which produces and accumulates [beta-carotene](https://en.wikipedia.org/wiki/Beta-carotene) in its seeds. It is called Golden Rice because the seeds are strikingly yellow. Golden Rice was created by Peter Bramley, Ingo Potrykus and Peter Beyer, working for an international cast of instutions including the Rockefeller Foundation, the Swiss Federal Institute of Technology and the University of Freiburg. Golden Rice was created by incorporating two genes responsible for the biosynthesis of beta-carotene, one from daffodils and the other from a nice little bacterium. The idea is that beta-carotene is a precursor of vitamin A, meaning that when humans eat it the human body coverts it into vitamin A. Normal rice does not contain any vitamin A to speak of. [Vitamin A deficiency](https://en.wikipedia.org/wiki/Vitamin_A_deficiency) is rampant in countries where rice is a staple food. A variety of rice which produces vitamin A is obviously useful. Golden Rice breeds true, meaning that if you plant seeds of Golden Rice you get Golden Rice. Since its creation, Golden Rice has been cross-bred with various local varieties of rice, thus obtaining sub-varieties which inherited the golden beta-carotene from the artificial variety and the hardness of their locally grown traditional parents. You may notice that both examples involve the modification of the wild-type genome by the addition of genes copied from other organisms. The sad truth is that at our current level of understanding of biochemistry we cannot really design a new protein and a new biochemical process with any degree of confidence. What genetic engineers mostly do is (1) identify a protein which would be nice to have, (2) find an organism which already makes it, (3) determine which gene encodes it, (4) use ultra-modern technology to incorporate that gene into the embryo of the target organism, and finally (5) hope for the best. But progress in unrelenting. We now have machinery which can synthesize DNA given the sequence of nucleotides. In 2010, Craig Venter, Clyde A. Hutchison III, and many others, of the J. Craig Venter Institute, were successful in synthesizing (called "DNA printing") the entire genome of a bacterium, [*Mycoplasma mycoides*](https://en.wikipedia.org/wiki/Mycoplasma_mycoides) starting from a computer record; the resulting DNA was then inserted into a cell of another species of bacterium, [*Mycoplasma capriolum*](https://en.wikipedia.org/wiki/Mycoplasma_capricolum), which had its original DNA removed. The combination worked, and is considered an entirely artificial species, [*Mycoplasma laboratorium*](https://en.wikipedia.org/wiki/Mycoplasma_laboratorium). And now comes the moral of the story. After creating their synthetic bacterium, the researchers went through iterations trying to remove genes one by one while still maintaing a fully functional bacterium. They are currently at version 3 of *M. laboratorium*, which has a genome containing as little as 473 genes. The kicker is that *149 of these genes are of unknown function*. We know they are necessary. We have no idea what they do. And we are speaking of a *bacterium*. Overall, the state of the art is as follows: 1. If we identify a protein which would be nice to have in an organism, and if we find an organism which makes it, and if we find the gene which encodes it, and the genes which regulate its expression, then we can try to incorporate those genes in the target organism. The rate of success is low, but non-zero. Sometimes it works as planned. 2. If we get from somewhere the sequence of nucleotides G-A-T-T-A-C-A of a novel gene, we have machinery which can print the DNA fragment which we can then try to incorporate in a bacterium and go to point 1 above. 3. We are learning more and more about how the components of the genome interact, making slow but visible progress into developing an understanding of larger and larger portions of the complete set. 4. Although at present we are nowhere near being able to *design* novel proteins, or novel biochemical pathways, which would result in some pre-defined phenotypical trait, it is clear that at some point in the future such knowlege will become available. Not now, not soon, but we are confident that such a day will eventually come in the fullness of time. ]
[Question] [ I want to create a planet that has the longest possible length of time that the tide is low to allow land animals to forage in the exposed shoreline ecosystems. What arrangement of star, planet and moon sizes and distances or other factors would allow a habitable earth-like planet to have the longest period of high and low tide? [Answer] **Gas giant moon, almost tidally locked.** Our moon travels around our planet and causes the tide as it goes pulling the ocean towards it. A smaller high tide occurs on the far side of the moon. [![tide](https://i.stack.imgur.com/LfEvq.png)](https://i.stack.imgur.com/LfEvq.png) <https://scijinks.gov/tides/> Your planet is the moon of a gas giant. As it travels around its giant, the giant pulls the ocean towards it in a serious way. Your planet is almost tidally locked, rotating to face the giant in sync with its orbit around it. The same section of planet faces the giant for long periods of time. Eventually your planet will be tidally locked and the high and low tide areas will be more or less fixed, changing only because of the more distant effects of the star. But it is not quite locked. The planet still rotates very slowly and so the high tide and low tide very gradually move across the latitudes. [Answer] Just put the Moon really close to geostationary orbit. If you have a moon exactly in a stationary orbit, the tides will not move... which means they might as well not exist. But if it's just a little bit higher or a little bit lower, then the tides will move very slowly--as fast as the moon appears to move relative to the ground. By adjusting the moon's altitude, and thus its orbital period, and more specifically the ratio of its orbital period to the planet's day, you can get the tides to move as slowly as you want (and thus for peaks and minima to last as long as you want), along with arbitrary day lengths. [Answer] You could try something more earth-like, starting from Earth and Moon configuration, by playing with these factors: * Mass of moon: to increase or decrease the tidal range. Doubling the mass also doubles the pull. I don't how that translates into height of the water tides. I am not astrophysicist, but as far as I can tell, changing the mass of the moon without changing its orbital speed won't change its orbit. * Rotation speed of planet: Drawing on @addaon comments (if I understood it well), there will be two tides per "day", so increasing the length of the day makes the tides slower. If you want low tides of double the time in Earth, half its rotation speed. * Orbital speed and distance of moon: faster and closer for longer and stronger tides (what you are looking for), slower and further for the opposite. Halving the distance implies multiplying by four the orbital speed (four times longer tides) and the gravitational pull. Corrections are welcome. ]
[Question] [ I'm trying to figure out the optimal sea depth on an artificial world (a Banks Orbital as it happens, though I think this would also be an important parameter for many other kinds of megastructure). Generally speaking, I think the oceans would not be kilometers deep as they are on Earth, as this would be both expensive and undesirable; making them shallow would be cheaper and better, because biological productivity would be higher with the seafloor nutrients closer to the sunlight from the surface. I have previously considered depth for shipping. Right now, I am looking at the question of what depth, or range of depths, would maximize biological productivity. I'm really interested in production of edible fish, but overall biological productivity would presumably be a good proxy for that, if that's what figures are available for. How exactly does biological productivity vary with sea depth? I know it goes very low when it's deeper than 200 meters, that being about as far as sunlight can penetrate at all. Is shallower always better? Is there a threshold such that 'at least this shallow' is optimal? Is there an optimal depth such that any shallower makes productivity start going down again? (And yes, I'm aware that the builders don't strictly *have* to care about biological productivity; if you have the technology to build a Banks Orbital, you could use nanofactories or suchlike to produce edible protein. I'm postulating a scenario in which they do care at least somewhat, in which it is one of the inputs to the decision-making process.) [Answer] Quoting from this [Nature paper](https://www.nature.com/scitable/knowledge/library/the-biological-productivity-of-the-ocean-70631104/) > > [![enter image description here](https://i.stack.imgur.com/126Ar.png)](https://i.stack.imgur.com/126Ar.png) > > > Due to the impoverishment of low latitude surface waters in N and P, the productivity of the low latitude ocean is typically described as nutrient limited. However, limitation by light is also at work (Figure 2). As one descends from sunlit but nutrient-deplete surface waters, the nutrient concentrations of the water rise, but light drops off. The cross-over from sunlit and nutrient-poor to dark and nutrient-rich typically occurs at roughly 80 m depth and is demarcated by the "deep chlorophyll maximum" (DCM; Figure 2) (Cullen 1982), a depth zone of elevated chlorophyll concentration due to higher phytoplankton biomass and/or a higher chlorophyll-to-bulk carbon ratio in the biomass. > > > It seems therefore that the peak productivity happens around 80 meters of depth. [Answer] # Around 70 meters deep. Most ocean life is around the coast, or on coral reefs which tend to be close to the surface. This is because coasts and reefs offer lots of minerals and valuable resources, land to hide in, and generally better conditions. To maximize the productivity, you'll want to have lots of coasts, reefs, and shallow enough water to maximize the amount of light. That said, as a frame challenge, water is pretty cheap. Most atoms are either hydrogen, helium, or oxygen. There's tons of water out there for any building projects and it's cheaper to have a deep ocean than to have a deep planet, and deep oceans are useful as buffers for planets in terms of storing heat and airborn gases. ]
[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/225448/edit). Closed 1 year ago. The community reviewed whether to reopen this question 1 year ago and left it closed: > > Original close reason(s) were not resolved > > > [Improve this question](/posts/225448/edit) One of my characters in a super hero setting can have their body turn into slime. By quirk of their power, they are able to process thoughts with their entire body, effectively turning their entire body into a brain, leaving them paralyzed while in "thinking mode". My question is, what would be the effect of increasing brain mass in such a way? Would the person be able to think faster or process thoughts in parallel? Or would it actually be worse overall? I understand that brain power depends a lot on the shape of the organ, so assume everything increases proportionally. Edit: If just increasing size and mass doesn't help, what properties the slime form would need to have to lead to an increase in 'brain power'? [Answer] # Unfit brain Let's skip by the problems of having only a brain, like the huge energy requirements, transport if nutrients and waste, filtering, immune and all that. We assume this still works magically and the whole body is a working brain. As mentioned in the question, shape is very important. We can see stark differences in brain mass and processing. Birds are a good example of well optimised brains for their size. Humans have a still unoptimised brain for the most part. Brain stem and cerebellum are quite old and optimised, but the youngest structures like the frontal cortex have grown incredibly fast, but not very dense. They will probably develop much more sulci and gyri, the ridges and canyons that make the distinct brain structure, as well as increasing mass. The take away is simple. Increasing brain mass means barely anything if it isn't optimised. A slimy brain seems unoptimised from the word go(ey). More damning is that brain structures are specialised. You can't have just random bits of brain. Each has a specific function with specific connections. The brain miracle is how it's still so plastic in receiving information, learning and making decisions on this information. Adding the rest of the body as a brain will just lock up the normally functioning brain with all the random signals. Even if they grow into specialised structures theres two more big hurdles. One is that most brains have limiting effects on others. Interesting research with electrical (over) stimulation shows you can make one brain half (part) numb, barely functioning. The other brain half won't be inhibited anymore, causing huge increases in it's function. As an example, people who sucked at drawing suddenly could make beautiful artwork. The other problem is electrical induction. A study showed that if neurons are packed too close together with a high volume can cause too much accidental signals in surrounding neurons. At a certain point this will make communication between neurons troublesome, if not impossible. Imagine it as sending morse code. Sometimes a random extra signal will still make an understandable message. If this increases to 20% of your message and at random, I'll become illegible. ## Making it work To make a 'slime brain' work you need to rework the whole brain. The advantage is that you do not rely too much on speed anymore. Movement requires quick decision making and making the move. Thinking about complex mathematical problems or why life, the universe and everything else us 42 can use relatively slow communication between specialised brain structures. So make highly specialised brain structures. The compactness of the brain doesn't need to increase, as only the mass counts. Not compacting is in this case advantageous to prevent spontaneous induction. The corpus callosum must change to facilitate much more connections to each structure cleanly and where appropriate. The resulting brain power is undetermined and highly dependent in the structures implemented. If it's all visual stimuli processing for the full spectrum with new and innovative ways of recognising your surroundings you do not have higher calculation power. If you also don't have eyes, or same human eyes, most of it will be useless. Even if you do all calculus or something similar it us difficult to say the increase. Most likely it'll be something exponential, but it is impossible to tell. Einstein revolutionised many fields while his brain wasn't extraordinary. Some people with more brain mass can't even learn a language. [Answer] If this superhero can either think or act while in slime form, then they won't be able to do *anything*. Mobile creatures that don't function using simple, hardwired reflexes need a brain to be able to decide what to do. Organisms as complex as humans need their brain for *all* movement other than their heartbeat. So, for this slime-hero to not think means that they won't be moving. To be unable to move while thinking means that they won't be moving. Either way, they're stuck. Of course, you could allow a progressive change from moving to thinking, so the character could either be strong, fast and dumb, or slow, weak and smart, or something in between. *That* might work. As to the relative brain power between slime form and normal form, let's look at some numbers. Normal humans have approximately: * 86 billion neurons in the brain. * 7000 connections per neuron * 602,000 billion connections total * 30,000 billion cells total In slime form, there are approximately: * 30,000 billion cells * 26 connections maximum per cell assuming cubic packing and both face and vertex connections * 780,000 billion connections total Since it is the number of connections that makes for processing power, slime-form has 130% the number of connections that the normal form has. So, naively, we could say that slime-form has 30% more intelligence when fully dedicated to processing rather than movement. It probably doesn't *actually* work that way, since the number of connections per cell is lower in slime form. [Answer] ## Size Doesn't Matter The brain of a Sperm Whale is five times larger than that of any human. Barring hither-to unknown levels of intelligence in cetaceans, it's fair to say that we're smarter than them. What's important is complexity. Our ability to form complex neural connections and pathways is contingent on having a very dense structure with a lot of surface-area for connections to form across. If you transformed yourself into 100% brain-tissue, you'd run into a major problem. Brain tissue is not unspecialised. You can't just add more of it and be smarter. It's how you use it that makes the difference, which should be intuitively obvious given that two people with roughly identical brain-mass can be so wildly different in intelligence! If you just turned yourself into 150 pounds of neurons, you wouldn't be thinking, you'd just be a blob of neural tissue that does nothing. What's needed is for the new brain tissue to be configured as part of the transformation. Think of it like a computer, or maybe its software. You can't just add more code. It has to be deliberate and reasoned and connected in the right ways or it simply doesn't work. A brain is a massively complex electrochemical computer and adding more neurons doesn't really help much. Properly done, a larger amount of brain-tissue would provide room for a great deal of complex processing and simulation beyond what's normal for a human (and don't underestimate how much that really is! Human brains are amazing) But you'd need it to be linked up properly, and structured for the task. [Answer] ### A brain isn't worth much if it has no connections The problem is that, while your character can transform their entire body into brain-matter, the ability for a brain to *think* is dependent on its neurons having pre-existing connections with each other, and these connections can only form while it is functioning as a brain. The best-case scenario when your hero first transforms into a slime is that they still have their functioning human brain somewhere inside their body and a basic pre-existing neural net that allows it to move, but the rest of the body is just random neurons which are useless for any kind of thinking. ### But it can form new ones If the magic allows it, perhaps they might be able to learn things in slime form and "store" the connection data somehow when they transform back into a human. They won't be able to *use* those connections in human form, but they might be able to re-establish them once they re-slimify. Over many years, if they spend enough time living in slime form, the slime form might eventually *become* super-intelligent since it has a bigger brain to work with. This super-intelligence will probably manifest mainly as an improved ability to store large amounts of information, but their ability to think more *quickly* will be limited since the connections per neuron are probably around the same as in human form. Still, having the ability to store large amounts of data might allow it to develop a better understanding of the world than a human would have. ### Dr Jekell and Mr Slime This will create an interesting situation, since it is not only knowledge that is stored in the brain, but personality as well. Their slime form may wind up with an entire alternative personality, which might "hear" the human personality as a "voice in its head" - since the entire human brain is functionally a tiny part of its body. While in human form, the slime personality will be effectively "frozen"; the human will be able to make their own decisions but will be unable to access the slime's super-intelligence. [Answer] The human brain isn't set up to be massively expanded, but it is set up to [network with other brains.](https://kottke.org/17/11/these-conjoined-twins-can-share-each-others-thoughts-vision) as conjoined twins prove. As such, the easy way for the slime brain to work is to have it work as multiple personalities. They can have different regions of brain which can independently focus on different things and solving problems. [Answer] **Human brains are already large.** Comparing with other animals, human brains are much larger than one would expect considering the body size. The ratio of brain weight to body weight is about 1:5000 for fish, 1:220 for birds, 1:180 for mammals and 1:50 for humans (highest). **Bigger brains are smarter, but not by much** As told in [this](https://www.sciencedaily.com/releases/2018/11/181130153847.htm) article, "The effect is there," says Nave, an assistant professor of marketing at Wharton. "On average, a person with a larger brain will tend to perform better on tests of cognition than one with a smaller brain. But size is only a small part of the picture, explaining about 2 percent of the variability in test performance. For educational attainment the effect was even smaller". One of the notable findings of the analysis related to differences between male and females. "Just like with height, there is a pretty substantial difference between males and females in brain volume, but this doesn't translate into a difference in cognitive performance," Nave says. **Brains of smarter people have bigger and faster neurons** As told in [this](https://www.humanbrainproject.eu/en/follow-hbp/news/brains-of-smarter-people-have-bigger-and-faster-neurons/) article, the scientist found that cells from people with higher IQ have longer, more complex dendrites and faster action potentials especially during increased activity. With computational modelling they could also show that neurons with larger dendrites and faster action potentials can process more information coming in and can pass more detailed information on to other neurons. **Conclusion** Make bigger and faster neurons, while increasing the size of brain only a little. ]
[Question] [ I'm working on a plot where nanites are used to increase muscle size and/or density directly and was wondering what scientific processes would be involved for nanites to do this. From what I understand on the science of working out, when we work out we induce microtears which grow muscles. *How would nanites do this directly where they make targeted microtears in order to increase muscles?* Obviously there are alternatives like having nanites deliver steroids to targeted areas (even now there are trials where nanites deliver drugs) but I was wondering about nanites doing microtearing specifically. [Answer] > > How would nanites do this directly where they make targeted microtears in order to increase muscles? > > > They would produce and deliver an enzyme directly into the muscles that would chemically break the muscle fiber. If you simply do this blindly you are just turning living tissue into dead tissue, but the nanites are smart enough to do it in a controlled way. They will tear the muscle just enough to simulate a good workout. Then they will help the healing process by building new aminoacids and testosterone out of bodily waste. The nanite user will be quite buff. [Answer] /nanites are used to increase muscle size and/or density directly / **Nanites accumulate in the muscle.** Nanites are more dense than muscle tissue. As more and more nanites accumulate in the muscle, muscle density will increase. The bulk of the nanites will also increase muscle size. Magnetic fields could be used to reposition nanites that might have shifted with time, or to alter the look of the nanite-enhanced muscles. [Answer] Muscle growth is signaled through a chemical called "Follistatin" and muscle breakdown is signaled through a chemical called "Myostatin". You don't need to make tears as much as you just need your nanites to hoover up any Myostatin they can find so that there's much more Follistatin around. Or just make their own analogue, something like [this one](https://faseb.onlinelibrary.wiley.com/doi/full/10.1096/fj.201801969RR) for example. I'm not sure that just tearing the muscle, without the associated spike in energy usage would do the job. You could also consider that there's other options for increasing muscle strength of regular humans using nanotechnology without adding any artificial reinforcements. For example using the nanites to prune defective mitochondria may give a benefit of strength and endurance (and crucially make it easier to gain further muscle mass). Otherwise, as the other answer above stated, you might need to go into much more detail about what limitations you want your nanites to have. [Answer] The nanites could modify the DNA inside the muscle cells so yes they could enhance muscle mass and density. However myofibrillar hypertrophy would be the king of hypertrophy prefferred rather than sarcoplasmic hypertrophy since the myofibrils are what makes muscles contract and produce form. The sarcoplasm is just the cytoplasm of the muscle cells and sarcoplasmic hypertrophy just make the muscle bigger and more bloated. ]
[Question] [ **This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information. I think I have made a mistake somewhere in my design of an untapered steel cable space elevator down to Earth. I was building this as a design reference to figure out how much stronger "stronger" materials needed to be to make one, and have made a mistake, I'm pretty sure. Some units : * Gravitational Constant (G) : $6.67 \times 10^{-11}$ * [Mass of Earth (M)](https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html) : $5.97 \times 10^{24}$ kg * Rotational Period of Earth : 24 hours * Density of Steel Cable ($\rho$) : 7,560 ${{kg}\over{m^3}}$ * Payload : 22,400 tons = 22.4 million kg Some formulae : * Rotational Velocity ($\omega$) : ${2 \pi} \over { 24 {{hr} \over {day}} \times 60 {{min} \over {hr}} \times 60 {{sec} \over {min}}}$ = 0.0000727, for Earth * Height of Space Elevator mid-station (d) : $\sqrt[3]{{GM} \over {\omega^2}}$ = 42,233 km, for Earth * Height (above ground) of Space Elevator (h) : $d - R\_{earth}$ = 35,970 km, for Earth * My understanding is that, if a sufficiently heavy counterweight is used, that not much more cable than (h) is required for the full cable run. * Relation of cable strength (S) to cable cross-sectional area (A), cable density ($\rho$), payload (P), cable length (h) and gravity (g ~ 9.8, for Earth) : $ SA = (P + Ah\rho)g \rightarrow S = {{(P + Ah\rho)g} \over {A}}$ When I put all these values in for a 6 cm diameter cable, I get a cable strength of 85.8 GPa (gigapascals). This is well within the boundary of modern steel (around 200 GPa). The amount of steel cable required would be 1.85 million tons. While the construction method is still beyond are technology, I was under the impression that the materials were also. Where have I made my mistake? [Answer] The glaring error is the fantastic value for the tensile strength of steel. The [tensile strength](https://en.wikipedia.org/wiki/Ultimate_tensile_strength) of steel is about 2500 MPa tops, OK let's assume super optimistically 5000 MPa. I have no idea from where you can get steel with a tensile strength of 200,000 MPa. Ignoring the payload, your formula reduces to $S = h\rho g$. Plugging in $h =$ 39,970,000 meters, $\rho =$ 7500 kg/m³, and $g =$ 9.81 m/s² I get $S =$ 2,940,793 MPa or 2941 GPa, about 600 times greater than the most optimistic tensile strength of any kind of steel. [Answer] Redoing your last equation, I got a figure of 2745 GPa ([wolfram alpha link](https://www.wolframalpha.com/input/?i=%28%2822.4e6%20kg%2Bpi*%283cm%29%5E2*35970%20km*7560%20kg%2Fm%5E3%29*9.81m%2Fs%5E2%29%2F%28pi*%283cm%29%5E2%29%20in%20GPa)), which is quite a bit higher than your number. I'm not sure where the 85.8 GPa mentioned came from That said, I believe you also need a counterweight. Right now, the centre of mass of your system is pretty far from geostationary orbit because the mass of the cable is a lot more than the mass of the orbital station. As a result, it would not have a stable position relative to the anchor point on Earth. Including the current mass of the cable into the payload mass to represent the counterweight increases the result of your equation to 9164 GPA, which is even higher. ([wolfram alpha link](https://www.wolframalpha.com/input/?i=%28%281.85e9kg%2B22.4e6%20kg%2Bpi*%283cm%29%5E2*35970%20km*7560%20kg%2Fm%5E3%29*9.81m%2Fs%5E2%29%2F%28pi*%283cm%29%5E2%29%20in%20GPa)) ]
[Question] [ Quite simply, given considerations like radiation protection, locations of scientific interest, local resources for building construction, water, propellant production, mining, etc, what would be the best place on Mars for establishing a base? I am running under the hypothetical situation in which SpaceX has partnered with NASA sometime in the early to mid 2030s to land humans on Mars, and now other companies, like Relativity space, are now joining in on Mars exploration. [Answer] > > the hypothetical situation in which SpaceX has partnered with NASA > > > Instead of hypotheticals, why not look at the work they've already done together? This 2019 [Business Insider article](https://www.businessinsider.com/spacex-starship-mars-landing-sites-map-hirise-2019-9) (paywalled, alas, though you can find text-only versions of the article in some less reputable places I shan't link to, just in case) took a look at some of the [HiRISE](https://en.wikipedia.org/wiki/HiRISE) image requests made by a NASA scientist in relation to some work with SpaceX, the precise details of which were under NDA. The current list of locations of interest [is here](https://www.uahirise.org/hiwish/search?cenLat=0.0&latRange=0.0&cenLon=0.0&lonRange=0.0&text=starship&word=on&sd=on&username=nwilliam&size=250), but the original article included this nice map: [![elevation map of Mars showing the nine candidate landing sites SpaceX is considering for its first Martian voyages of Starship](https://i.stack.imgur.com/NMyIp.jpg) The two big peaks you can see there are Elysium Mons at the left, and Olympus mons at the far right. Most of the regions of interest are in Arcadia Planitia, based on the belief that it will be easiest to obtain water from there, which you'll be needing in order to do stuff like make rocket fuel to travel to and from Earth economically. There's a secondary benefit about the Arcadia site, which is that it is in a relatively low-lying area of Mars which means that the atmosphere is thicker and so the cosmic radiation dosage is somewhat reduced: [![a map of cosmic radiation exposure on Mars' surface, in rem/yr](https://i.stack.imgur.com/96U2v.jpg)](https://i.stack.imgur.com/96U2v.jpg) This map doesn't conveniently match up with the google-mars generated image above, but you can just about see Elysium at the upper-right of the left hand hemisphere, and Olympus Mons just left on centre on the right hemisphere. Whilst there are tradeoffs to be made (thicker atmosphere means more problems from dust storms) there's clearly good reason to be visiting that part of the planet. As for science... well. *Everywhere* on Mars will be interesting to some degree... whilst other places might have greater interest, you still need to be able to support scientific investigation of those places, and teleoperation of robots or even visits in person will be vastly easier given a decent base camp to work from, and that'll be the main driver of early manned stuff, I'll bet. Putting boots on Mars will be too difficult and too expensive otherwise. [Answer] For a permanent base, it would be convenient to have water nearby! This is the **North Pole** of planet Mars, [![The martian north pole](https://i.stack.imgur.com/dvBCf.png)](https://i.stack.imgur.com/dvBCf.png) [Answer] Considering that the first settlers will have to deal with an hostile environment, a plausible location could be at the bottom of Valles Marineris, where atmospheric pressure is about as double as on the martian surface (see my [other answer](https://worldbuilding.stackexchange.com/a/119612/30492)). Though not favorable to life, a lower pressure differential between inside and outside means a lower stress on the structures where the settlers reside and therefore a higher reliability of the same structures. There would also be a slightly better protection from solar radiation, due to the thicker atmospheric layer above their head. ]
[Question] [ Ok, so I'm willing to bet at least one person has looked at the title of this question and thought to themselves "What?", so I'll try and explain this as thoroughly as I can. Most incarnations of Pyrokinesis I've seen in fiction often deal with either telekinetically starting fires by exciting the flammable properties within the objects around them, or just straight up creating and releasing fire from within a person's body (the science behind this particular incarnation of the ability often varies from each piece of work). Some pyrokinetic people in fiction however, are capable of moving and shaping fires that are around them, sorta like how Aerokinesis lets you move air/wind and apply a shape to it. Since fire is nothing but the result of a flammable material/substance getting exposed to oxygen and heat, this got me thinking. What are pyrokinetic people actually moving when they use their powers? Calling it fire seems inaccurate seeing as how fire itself lacks weight, cannot exist without certain requirements, and is treated less like a 'thing' but more so a chemical reaction. My understanding on science is how you say "Painfully mediocre", so I wonder if any of you guys and girls could help me out? [Answer] Let's begin with one of the best explanations for making fire by magic I've ever heard: [vibrating molecules](https://www.youtube.com/watch?v=bkNPcl7t2Zw&t=28s). > > What you need is a basic combat spell, making fire. What causes molecules to heat up? *They vibrate.* Everything you see is in a constant state of vibration, thus the illusion of solidity. But how do we take that which appears solid and have it burst into flames? We *will* the vibrations to go faster.... ([The Sorcerer's Apprentice (2010)](https://en.wikipedia.org/wiki/The_Sorcerer%27s_Apprentice_(2010_film))) > > > People think fire is an *element.* But from one point of view, it's no more an element than ice. Oversimplifying to the point of making angels weep, it's nothing more than another [state of matter](https://en.wikipedia.org/wiki/List_of_states_of_matter): plasma. That's why that previous quote is so fun: your pyrokinetics are actually creating and manipulating plasma. In other words, they're not manipulating fire, they're causing atoms and molecules to vibrate to force them into a plasmatic state. It's the other point of view (the more common one) that's a problem. You see, *Flame* may contain plasma, but it isn't plasma. > > An everyday wax candle has a flame that burns at a maximum temperature of 1,500 degrees Celsius, which is too low to create very many ions. A candle flame is therefore not a plasma. Note that the vibrant red-orange-yellow colors that we see in a flame are not created from the flame being a plasma. Rather, these colors are emitted by incompletely-burnt particles of fuel ("soot") that are so hot that they are glowing like an electric toaster element. If you pump enough oxygen into a flame, the combustion becomes complete and the red-orange-yellow flame goes away. ("[Do flames contain plasma?](https://wtamu.edu/%7Ecbaird/sq/2014/05/28/do-flames-contain-plasma/)") > > > This is the problem with the idea of a pyrokinetic "moving" flame. Most flame is simply inefficient combustion, and the odds are the combustive process will complete long before you can move it anywhere. Oxygen depletes, as does the fuel source. That's why the plasma definition is so much more interesting — because in the case of combustion, your character isn't really a pyrokinetic, they're just a telekinetic that happens to be moving around the proverbial burning stick. **What you have is a multi-talented character** A true pyrokinetic must have two abilities: the ability to convert some substance into its plasmatic state and the subsequent ability to move that material around. For my money, moving something around is a bit unrealistic. Think about it, you're connecting with how many bazillion atoms to move them around? What makes more sense is that you can *encapsulate* a region of space. Let's say a sphere 100cm in diameter. It's the *sphere* that's being moved — not the material inside of it — and it's the contents of the *sphere* that can be caused to vibrate with such venom as to become a plasma. Shaping the "fire" is nothing more than learning how to shape the encapsulating sphere. However, the consequence of this explanation is that the sphere must, by definition, not allow the heat of the plasma to escape. It's encapsulating everything (otherwise you couldn't contain or shape it in the first place). This means that to burn something the pyrokinetic must free (un-encapsulate) the mass he/she is manipulating. If this isn't done, what you have is the equivalent of a really cool looking dodge ball. *However, to be fair, something is escaping... light (otherwise the effect is a black sphere and that's boring). If light can escape, then for practical purposes, so can other frequencies in the electromagnetic spectrum. Not heat, just light. But this has an interesting consequence. If you heat a plasma up enough, the intensity of the light could burn things. However, we'd need someone better schooled in plasma physics to confirm this.* [Answer] **Moving a match** How do you normally move fire? You might shape the fire with funnels or wind, but the starting point is always the same. The flammable material. If you want to move the fire of a match, you move the match. Moving the match moves the flammable material, which in turn moves the origin point of the flame. With telekinesis you want to move the flammable material as well, be it oil fumes or burning wood. Shaping of flame can be done afterwards with wind and funnels, which is basically pressure the flame cannot overcome. Telekinesis can so this as well while mindful of the limitations of the flame, like reach, starting point and duration. [Answer] This is the type of insightful deliberation that totally kills fantasy. There is a reason why it is called 'fantasy'. It just has to be something you do not think about or subject to intense scrutiny. Better to just leave it as, well, fantasy. You are absolutely correct in bringing our attention to the reality that 'fire' is a very nebulous term. It is a concept. Really, no one has ever been injured by 'fire', they are injured by either the intense heat, or the toxic components of combustion, or the combustion (chemical reaction) itself. Firefighters are trained to and learn to ignore the 'fire', but concentrate on the individual very real dangers. That 'flame' will not injure you, but the heat, the smoke, the weakened floor, and lack of oxygen will. Any 'manipulation of fire' would, in essence, be the manipulation of one or more of these factors, not the 'fire' itself. As you point out, what we call 'fire' is really just a perceptual, conceptual thing, not a physical thing. It only occurs in our mind. What exists in reality is the heat, the radiation, the products of combustion, and the results of combustion (the destruction of the fuel as it changes its chemistry). These things we conceptually all lump together and label as something called 'fire', and then put an emotional tag of 'bad and dangerous' to it. Once labeled and tagged, our minds have the distinct ability to handle it as a concept, and respond to the emotional tag. Thereafter the concept can be manipulated and altered, without needing to reference the underlying reality of the 'things' that actually make up the concept, and we continue to apply the emotional tag to the manipulated concept. We treat the concept, and the emotional tag, as a separate entity from all of its parts. The 'whole' still exists even if none of its parts continue to exist. We become afraid of the tag, the label, not the reality. Long after there is no danger from the reality of the components of this concept we call 'fire', we are still in fear of the concept called 'fire'. The word itself takes on a reality of its own. It's like talking about the hazards of 'falling'. There is no such thing as ***a fall***. Everything is 'falling'. There is absolutely no danger in a fall, per say. It is the sudden stop at the end that creates the damage. Yet we still fear the fall, not the sudden stop at the end. Even in amusement park rides, when the danger of any sudden stop is removed, we still fear the fall. Like saying 'I don't like vegetables', as if the label were a real thing. As the commercial infers, say 'fries are vegetables', and suddenly you do not like them. Fantasy is really all about these labels and tags that our mind forms and creates, and our emotional reaction to these tags, not the reality behind them. So render unto fantasy what is fantasy, and onto reality what is reality. Never conflict the two. Humans tend to like their emotional tags, thank you very much. [Answer] What is fire? Fire happens normally when objects oxidize quickly, but in the case of pyrokinesis / telekinesis of fire, in my mind, there is an implication of the ability of the caster to facilitate the transfer of energy between molecules. Therefore, when someone is "telekinetically moving/shaping fire," they are transferring energy from the particles in one region of space to the particles in another region of space. So similar to what @DWKraus says in their comment, telekinesis of fire should allow the user to move energy to cause molecular heating. However, I think generalizing it in this way has its benefits, and can potentially take the idea of moving/shaping fire to the next level. What happens, for example, when energy is concentrated in a certain location? Since kinetic energy actually has mass (and since mass and energy are equivalent by E=mc^2), moving/shaping fire could even be the basis for abilities that control mass or gravity, or even slow and alter the movement of time, given the connection that gravity has to time. Makes the ability a lot more interesting to think of it this way, but that's just my 2 cents ]
[Question] [ In a space-faring, war-torn world with mostly-realistic technology, the engineers have been developing **laser** weaponry and defenses. All sides of the war have roughly equal technology. This question [How to protect your ship against TW-range lasers?](https://worldbuilding.stackexchange.com/questions/115532/how-to-protect-your-ship-against-tw-range-lasers) provides a good Q&A regarding different approaches to defend against a laser that is able to fire 50TW of energy over the course of a minute (without self-destructing). For laser weapons of that power we have to assume that the attackers have the capability to *focus* a large amount of energy through a lens, and are able to *dissipate* a massive amount of energy. Using that same technology wouldn't defenders be able to refract any laser attack away using lenses, and/or dissipate the heat of the attack? Or is there some way that laser technology gives an advantage to the attacker? [Answer] > > wouldn't defenders be able to refract any laser attack away using lenses, and/or dissipate the heat of the attack? > > > This is a common misconception (here and elsewhere) in which people really don't appreciate the power levels of a practical laser weapon. That's fair enough; it isn't intuitive. First, note that your lasers *probably* won't be using refractive elements, because they'll be hard to cool. Mirrors are more convenient in that regard, as you can put coolant channels on the non-business side. They also give you the ability to have deformable mirrors and so on. Next note that the energy density at the mirror is going to be much, much lower than the energy density at the target: this should be obvious, because you don't want to incinerate your own optical path, and you don't want the enemy to be able to trivially defend themselves by simply fitting mirror armour. As the intensity of light incident upon the target goes up, you start getting non-linear effects. One such effect is multiphoton ionisation, whereby highly intense light of longer wavelengths (say, visible) can blast the electrons off matter it interacts with. Once this starts happening to the target, no amount of magical heat-sinking will help because free electrons floating around will do bad, bad things to the chemical and crystal structure of the material. This also applies to lasers emitting ionising radiation, such as UV or X-rays, though these will be harder to engineer than longer wavelength devices. Finally note that even for purely thermal effects, the thermal conductivity of your armour plate and structural materials is limited. Even if you have more that enough cooling capacity to keep your ship lovely and cold even in the face of a terawatt of heat, the point at which the laser hits will likely heat up faster than you can cool it down so you'll *still* take damage. Some scifi settings introduce "thermal superconductors" to handle the latter, but remember that they won't save you from ionising effects! --- There *may* be plausible ways to defend yourself effectively from laser attack, but they are even more science-fictional than practical laser weapons. It *may* be possible to produce a cloud of dense [cold plasma](https://en.wikipedia.org/wiki/Nonthermal_plasma) and hold it in a magnetic field on the outside of your ship. It would clearly look awesome: it glows! It could also be opaque to lasers, which would have to burn off the shield cloud *first* before reaching the hull, and the shield cloud could be refreshed from within the ship. Getting the cloud dense enough, and holding it in place under strong external heating is extremely hard, but it might work. It certainly isn't the same technology needed to build your massive laser cannon... different branch of physics and engineering entirely, and a lot more advanced. But you can say "*all power to the forward shields!*", and really, that would make it all worthwhile. [Answer] > > Using that same technology wouldn't defenders be able to refract any laser attack away using lenses, and/or dissipate the heat of the attack? Or is there some way that laser technology gives an advantage to the attacker? > > > Neither. For the former: we can focus frankly absurd amounts of energy in small areas quite easily (we smelt tungsten pretty easily), but that doesn't imply that we could make something to survive that environment. There are two major issues here: 1. The attackers know precisely where all of their energy is going, and can keep everything perfectly aligned so that everything stays under material limits, whereas the defender has to deal with it coming in at any point from any direction, which is far harder. 2. The attackers can focus energy from multiple emitters on one point, whereas the defenders have to deal with all of the energy at the point it's arriving. For the latter: the defences against lasers are much lower-tech than lasers: fundamentally, you just need to either put a bunch of stuff in the way, preferably reflective/shiny stuff, or move fast enough/unpredictably enough that the enemy can't keep their lasers pointed at you well enough to get through whatever stuff you have in the way. Neither of these require any particular technology. [Answer] # *Pax Armada* As [user3482749 said](https://worldbuilding.stackexchange.com/a/196810/21222), it is very complicated to use the same laser technology to deflect/defract/block incoming lasers. However, that is a technicality. If you have a fleet with lasers, your defense against lasering from others is the threat of retaliation. If they shoot one of your ships down, you will shoot back. As long as the cost of conflict remains much higher than the cost of peace, things will be chill. Don't forget to make alliances with more people who also have lasers. The more the merrier. ]
[Question] [ In a [previous question,](https://worldbuilding.stackexchange.com/questions/195474/how-can-my-town-be-public-knowledge-while-still-keeping-outsiders-out) I brought up the concept of sanctuary towns, towns populated entirely by people who know about the population of immortal (as in they can't get old or sick; they can still be killed) supernatural creatures living in secret amongst humanity. Everyone in the town is either an immortal or a human who knows that immortals exist, and they make sure to keep non-immortals from visiting by means that this site so awesomely helped me work out. This allows the immortals in this town to openly be themselves without having to worry about things like having to pass for human and the like. Now, immortals generally live as members of various clans, which each have territory as well as vague borders with the territory of other clans. Said clans... do not always get along, and frequently get into skirmishes or try to drive rival clan members out or kill them to expand their territory. But when I've tried to visualize how these turf wars play out, one part of it is giving me serious trouble. When it comes to most places where immortals live, where there are no sanctuary towns and it's just a question of killing or ousting the minority of the town or city's population that belongs to rival clans, that I think I've got the hang of the details of. The problem comes with these sanctuary towns. Killing all of the rival vampires or werewolves in a normal city or even a normal *state* would probably fall sufficiently within normal expected death and crime rates that they could proceed with business as usual as long as the murders weren't traced back to them. But you can't do that with a sanctuary town. If you try to take over a sanctuary town like it's some kind of military siege, killing or even just driving out all of the rival clan's inhabitants... I just don't see how you could possibly keep people from finding out that the inhabitants of that town have completely changed overnight. These towns may be secretive and generally isolated, but I seriously doubt that'd be enough that the entire population could be replaced overnight and nobody would ever notice. These towns have enough trouble dealing with the inevitable interactions they have to have with the state government without having to deal with the issue of most of the population changing completely since the last time they checked. So it seems obvious that these clans are going to need some slightly different tactics if they're going to keep safety in numbers from making their rival clans' strongholds completely unassailable. **If an immortal clan *really* wanted to expand their territory and completely take over one of their rivals' sanctuary towns, how would they do this without getting the unaware humans of the outside world extremely suspicious about the massive death toll or exodus that would be sure to follow if they actually *succeeded?*** [Answer] ## Frame Shift: The residents of the town are why you are capturing it. **Gentle conquest and fair parole:** What resource is available in a sanctuary town that you need to eliminate the residents to take it from them, then fill the town with your own people? For most of your immortals, the resources they are seeking are *people*. Either human cattle to do your bidding, or immortal allies/servants. In either case, the less disruption to your town, the better. If not to capture the people, then in the case of immortals, to force them to move elsewhere. Immortals didn't get that way by fighting to the death and never rolling with the punches. If they did, they would have died long ago. So your immortals will have some kind of ingrained etiquette about war and conquest amongst them. One of the reasons I've heard that the Japanese were so brutal to their POW's was that they DIDN'T have a long military tradition, and their vision of war was highly ideological. All-or-nothing works if you are short-lived and fighting only one war. Europeans had a whole culture developed around cyclical warfare, where prisoners were treated semi-decently (especially high-ranking ones, and there was little motive to punish low rank) because today's enemies would be tomorrow's allies. So your immortals would work out a system where conquerors would assure that defeated rivals got to retain at least some of their power, wealth, and prestige. The defeated would similarly be expected to at least nominally follow parole and stay out of the remaining conflict. Knowing the world wasn't coming to an end just because you were conquered would mean that folks would be willing to follow the rules of the masquerade in their battles, and surrender to foes that would treat them/most of them pretty decently. Given immortals, honor, duty, and personal reputation would be things warriors and generals/conquerors would spend years if not centuries developing. The tsarina of Paris has a reputation for keeping her word that goes back centuries. Vlad Dracula ("the Impaler") can't win a war because everyone fights to the death and keeps bringing up that incident with the Turks... You might even have a body of adjudicators who's job it was to monitor such agreements/settlements, and black-list those who violated it - a sort of UN/supreme court of the supernatural. I would model it on an Aristoi system, where Adjudicators were selected to be as neutral and unrewarded as practical. It would only work if they were considered above influence. * In the US, at least, there is an extensive private prison system, with enormous prisons build out in the middle of no-where. Such a facility could be under the administration of the Aristoi and used to house and control prisoners from these conflicts. The goal of such places is to be noticed as little as possible, and people don't like thinking about prisons. they could even be located near sanctuary towns on purpose, so the workers are trustworthy. After a battle, you house the prisoners until a deal can be struck about the subsequent peace agreement. [Answer] Few ideas: * Brute force: Cut the phone lines leading into town so no one can 911, and litterally kill everyone in one night and take their place. Dig a mass grave, bury them all, assume their identities (many of which were already fake as they're immortal) and reconnect the phone lines. So long as the waitress at the diner is still friendly and has a convincing story (oh the last girl? she finally got into college!) No one will notice unless they look deeply. * Local elections. In the USA most civic roles are the result of elections, and the optional voting system can result in poor turnout to the minutiae of politics. Move your allies into the outskirts of town keep a low profile, and on election day have 100% turnout. Then your new sheriff can roundup and arrest the others. * Financial attacks - ie throw money at the problem. Undercut all their manufacturing and service businesses until they're unemployed and poor, then come in and offer to buy their property for much more than it's worth. * Use the government. Use that big beurocracy to solve your problem. Out every criminal in there to the FBI. All the immortals are using fake ids so tip them off to ICE as illegal immigrants. And the immortals that arent using fake ids: Tip medicial researchers off that there are immortals they can vivisect and learn eternal life. (If theres any shady organisation in the USA who can make people disappear- its be big pharma). Then buy up their properties at the police auctions. [Answer] Adding to what @DWKraus said, you need to ask *why* your characters want to take over a rival town. Wars in human history have typically been fought over land or resources of some kind. Even in cases where the conflict is driven by petty nobles whose honor has been slighted or long-standing feuds, there is often some initial conflict that triggers the feud in the first place, such as a dispute over land rights or an accident between hunting parties gone wrong. The rank-and-file, at the least, will have to be given a good enough reason to risk their lives and the lives of their families (if they disrupt the masquerade) if they go to war. There are ways to make people willing to die over a feud or abstract cause, they aren't likely to be willing to die for the sake of someone else's honor. If it's land, their goal is to drive the people off the land in order for them to control the resources therein (resources in this case also possible meaning muggles). This means you have to get rid of the people but leave the infrastructure in-tact or it's a net loss. But, this causes problems in that you have to exert control over your conquered land, which will be difficult when most of your clan's population lives in a single town that due to the nature of your setting is likely to be far away from your center of power. Controlling another town rather than just making them bend the knee will be really, really hard. You also have to ask yourself what do the characters get out of conquering someone else's land that they can't get on their own. If the supernaturals live in small, isolated communities, that implies they have a lot of land and resources between them that they can divide up. If it's people, your immortals will either want to enslave them or convince them to join their side. These still involve different tactics: enslavement involves brutally suppressing the locals until they bow to your will (if not outright brainwashing them if your vampires can do that), convincing them to join you involves toppling the people at the top *and* you need to restrict collateral damage enough to avoid resentment. If it's personal satisfaction/honor or political power they don't need the town in tact afterwards and can resort to tactics like burning down the town in a fire or drowning it by rupturing a dam. All they care about is wiping it off of a map. Alternatively, your characters *don't* try to hide their actions from the muggles. Making an entire community disappear overnight makes a statement, it shows to other supernaturals how powerful you think you are given you've made an entire town disappear and are effectively telling the muggles and supernaturals just try to do something about it. It's a statement that you think you're stronger than everyone else. It also provides an implicit threat, that you're willing to do anything to win and if other supernaturals stand in your way you're willing to fight so dirty it bursts the masquerade wide open, because you don't care about the consequences. A comparable example might be how people like Genghis Khan, the Norse, and (surprise surprise) Vlad III the Impaler used word of their atrocities as a planned gesture to intimidate people into capitulating and make an example out of those who stood against them, even if they weren't bloodthirsty maniacs. Additionally, because the other supernaturals live in distant towns, killing all the inhabitants of a town in, say, Pennsylvania might not necessarily lead authorities back to one in New York. [Answer] **Managed engagement**. In the first problem my solution was that you have "charmed" everyone who regularly enters the town, or blunders into it, and they give false, discouraging accounts of what happens inside, and report back on anyone else planning on entering. So if a war breaks out, under no circumstances does their programming include letting anyone know. Provided you can pull your forces within this human perimeter, and don't make excessively loud bangs or bright flashes in the sky, and supposing you have *some* solution for 1990s-era spy satellites which were a drawback for all the plans in the previous question ... then you should be able to hold the war unmolested. If a larger siege perimeter is needed, it would be set up the same way as any new refuge - by managed engagement. You would need to charm everyone interacting with the perimeter region, and ideally you would charm all the humans previously charmed by the besieged town, so they could give a convincing impression nothing is happening, while denying supplies to those inside. [Answer] Fights are decided by single combat between champions for each side. Winner demands allegiance. Why would someone who would otherwise be immortal endanger their long life by refusing to accept the tradition? Same job, new management. ]
[Question] [ I was working on a story project some years ago which featured a highly alternate near future in which, among other things, a 3-way cold war had spread across the solar system. There were many other F&SF aspects mostly irrelevant to this question, so I'm not (necessarily) asking for why space travel developed faster in this world. The issue is... What could lead to a post-WW2 world where Western Allies, Communists and fascists are locked in a three-way standoff? The real WW2 featured a team-up of the "West" and "East" Blocs against the "Central", which broke down into a conflict between the winning alliance. Axis victory scenarios typically lead to a Cold War, but of the variety "East loses, standoff between West and Center"; the USSR is conquered, or reduced to a rump state that's no longer a great power. My first idea was "A plot to kill Hitler succeeded." Post-Hitler Germany was then able to secure a truce, USA-USSR relations break down without a common enemy, all 3 sides develop the atomic bomb, an unconquered Germany is first into space... I don't think that's a good answer, though. It ignores that Axis =/= Germany. Germany (almost) alone can't come close enough to matching the industrial power of the other two blocs, thus can't credibly sustain a cold war with them for generations. So I'm asking for something better. No, "WW2 didn't happen" isn't an acceptable answer, even though the desired "present" situation bears some resemblance to the pre-WW2 situation. *Some* kind of major war has to have still happened circa 1940. *Clarification:* The story expected / required that the "present" situation have USA, UK (and at least preferably also France) in the Western bloc, Russia/USSR and at least part of China in the Eastern bloc, Germany, Japan (and at least preferably also Italy) in the Central bloc. This means your answer has to allow all the powers to remain in (or get back into) place after the war. (Different situation from [Could Nazi Germany, Surviving WWII, Survive the Cold War?](https://worldbuilding.stackexchange.com/questions/53768/could-nazi-germany-surviving-wwii-survive-the-cold-war) , I think.) [Answer] The key to your scenario is the phrase "stand-off". In the real world, that two party stand-off was created by the presence of nuclear weapons and the threat of mutual insured destruction. There is no reason that this proven source of stand-off couldn't be spread across more participants. You are embracing an alternative near-future which already involves accelerated technological growth. Why not start that acceleration a little earlier by allowing all three of the would-be super powers to master weaponized nuclear fusion at approximately the same time. If within a few weeks of each other, each of the major powers proved their nuclear capacity by annihilating an enemy city, they might very quickly find themselves equally motivated to negotiate for peace. And once peace is achieved, a three-way cold war can smolder on slowly for as long as your story needs. So the question becomes, how do you justify a simultaneous scientific discovery to your readers? Personally, I would use spies. [Answer] **Britain falls, US fights Japan but not Germany** It is hard to imagine an **alternate history** where Germany defeats the US. But imagine Britain going under in 1940 or early 1941. The mechanisms for that might include * more credible preparations for Sealion from 1935 onwards (high numbers of channel-crossing LCMs being built instead of useless capital ships, better subs to screen them), * a less drastic Blitzkrieg in France and the Low Countries, lasting a few months longer and drawing in a greater proportion of the British Army, * followed by a more complete Dunkirk debacle (perhaps they fell back to Le Havre or Cherbourg, and the subs mentioned above closed the channel). The US is denied a staging base close to the continent, and anyway they have been grievously hit by the Japanese. Again going on a limb, Japan realized that simply bombing Pearl Harbor would enrage America but not cripple it, so they gambled to add an invasion force to the mix. (Closer possessions like the Philippines were to *wither on the limb* once Hawaii fell.) The US still wins, but it is clearly *Pacific First* for them. Meanwhile, the Nazis concentrate on the Russians. The fight goes slightly better than it did historically, with no lend-lease for the Soviet Union and more of the limited German manpower. The Nazis still get bogged down in the vast eastern steppes because * the Soviet Union had a larger population and a large industry, * they managed to withdraw much of their industry behind the Urals, * German actions in the occupied territories trigger a fierce partisan resistance, and each mile eastwards increases the need for lines-of-communications troops. Imagine a costly stalemate, with Stalingrad repeated in Kazan, Samara, Moscow, Perm. Both sides bleed each other dry. It is hard to imagine that the situation above would lead to Korean-style armistice negotiations, but perhaps they do. Replace both dictators by more reasonable men at a late stage? All three sides had nuclear programs from 43 or 44 onwards. The American one was the most advanced, but still **severely** limited in the number of bombs they could produce. One or two dozen would not enable a transatlantic invasion, and the US didn't have more than that until the East Front armistice. Both Nazis and Soviets were in the single digits. They might have used them on tactical targets, or not, either way they failed to break the stalemate. Neither side had air forces to reach the enemy industrial centers. [Answer] **Nuclear war.** The USSR now is Siberia and Soviet central Asia. The capital of the US is now Shreveport, LA. Neither country is now a super power. Fascism however is alive and well in South America, and Argentina now occupies the entire continent up to the Panama canal, with the exception of a small remnant Brazil. Allied with Argentina is Franco's Spain as well as a confederacy of West African nations. Communist china made the same mistakes it did in our timeline but now has gotten its act together. Absent containment by the US and USSR, China began aggressive expansionism and has acquired Japan, Korea and is in the process of doing the same for Southeast Asia. Europe also suffered in the nuclear exchange with the UK suffering a fate similar to the US. Central europe fared better and with the fall of the USSR the EU acquired many nations once in the orbit of the USSR. None of these countries are the formidable powers that the US or USSR were in their heydays and so this scenario is 2 steps away from what was. Mixing it up more means less constraint from actual history, while still keeping the fun elements of actual history. [Answer] Well, a cold war in an era where humans have spread around the solar system is rather easy because wide access to WMDs (big rocks) is available. Provided you know where the enemy is, you can accelerate some asteroids and set up their trajectories in a manner where they would be extremely difficult to block. Big rocks falling from space onto planets, moons, or into space stations would be far more destructive than nuclear weaponry. Because of this, I personally doubt the assertion that Germany wouldn't be able to hold a multi-generational cold war. If they have access to WMD's (nukes or asteroid impactors), they can "play at the big boys table" even from a position of weakness for an extended period of time. As for WWII, this is my personal opinion on how you could accomplish this (but keep in mind I'm not a historian): First, the superpowers that end up are the "West", Germany, and the USSR. While Japan in WWII had some unmatched advantages such as their unbreakable morale and superior aircraft at the beginning of the war, I'm of the opinion that their war against the USA and the other Allied nations was always doomed to failure. Their cultural attitude towards the war blinded them towards strategies that eventually led to their defeat and they simply didn't have the resources or economic umpf to not get simply stepped on by the USA once their wartime production got into swing. Furthermore, their allies in Germany and Italy were too far away to really assist and while there is some unusually high cultural compatibility with the Germans and the Japanese of the time, the only reason they're on the same side (in my, non-educated opinion) is that they're so far apart. Japan wanted Imperialism and Germany was far enough away that they'd never need to fight each other. As for how to prevent Germany from losing the war? Easy, just make it so that when Hitler ascends to power, he's unable to install his party as leadership too. For some reason (this can be really minor like one politician who's more charismatic or one person who dies at the wrong time), his coup of the German government fails, and while he becomes a popular figurehead and chancellor of the German people, he ends up not in charge of the military strategy. WWII still happens though, because it's generally popular among the high-politics of Germany at the time. The difference is that Germany "wins" though: Instead of having Hitler in charge, competent generals and politicians decide on military strategy and avoid things like fighting the war on two fronts (maybe only engage Russia minimally) and they also avoid the atrocities like gas chambers (which were Hitler's pet project). The Reich still ends up Nationalistic and Hitler's antisemitism is still popular, but things don't get bad enough that the countries get their knickers in a twist over moral indignation. Germany ends up conquering most of central Europe up to the Spanish border, and controls basically everything as seen in this map except maybe not so far to the East because they avoid conflict with Russia: [![German Reich](https://i.stack.imgur.com/VIbss.png)](https://i.stack.imgur.com/VIbss.png) Once Germany has control over basically all of continental Europe barring Spain and Turkey, instead of fighting Russia and the UK, the competent leadership decides that enough is enough and the nation turns to fortifying and concentrating their control over their new nation. With this much land and so many people under their control, there's no reason that the German Nation wouldn't be a superpower to rival the USSR and the Allies. ]
[Question] [ ## Premise The surface of my world cannot support life. The inhabitants of my world sustain themselves off troglophauna and aquifers. I'm leaving the mechanics of where energy comes from in this shadow-ecosystem out of scope (we can just assume it's geo-thermal or other source). I also have a evolutionary narrative as to how troglodytes can evolve into bipedal human-like creatures. This has freed up my inhabitants' hands to put pen to paper -- or rather chisel braille, since there is no light or bio-luminescence. Now, I'm at the juncture in my world where I am to size the potential of such a race -- whether they can achieve some of the hallmarks of a civilization as we know it on Earth. At first, I thought: "Use braille! Wam, bam, super easy." And this may well have advanced the society a fair amount. After all, literacy among Earthlings in Medieval times was rather concentrated but still enabled the construction of cathedrals and other notable achievements. So it's easy to imagine a troglodytic analog of nobility/artisans along those lines: "those who hear the walls." Yet on further consideration, the troglodytes may not be able to go beyond this. There are no trees nor similar input materials to serve as cheap materials to inscribe the braille onto. There is perhaps no exact Earth analog for this kind of obstacle, but I would hazard the situation to be comparable to an Earth without a printing press. In this way, knowledge and literature may serve as a key step towards being a full-fledged civilization, but at this juncture, it seems that the literature and depth of authorship will be very shallow. ## Question How can a troglodytic society democratize braille literature, given there are no trogloflora for cheap materials? **Further clarifications** * World is [earth-like](/questions/tagged/earth-like "show questions tagged 'earth-like'") minus surface life * No trogloflora * There is troglophauna (but tend to be only used for sustenance, not *that* flush) [Answer] **Skin:** Textured skin decorations could easily be symbolic or pictographic as the [Mursi tribe](https://en.wikipedia.org/wiki/Mursi_people) in Ethiopia attest, perhaps speaking of status, achievements, marital status or personal history or allegiances: [![enter image description here](https://i.stack.imgur.com/NGHBK.jpg)](https://i.stack.imgur.com/NGHBK.jpg) Flickr unattributed **Vellum.** Skins of the dead would be prepared by soaking in a mixture of urine and feces then scraping and washing. Before drying, an impression can be forced into the surface from behind to create a palpable bump, ridge or texture as desired: [![enter image description here](https://i.stack.imgur.com/Ygb9M.jpg)](https://i.stack.imgur.com/Ygb9M.jpg) Copyright [Wikipedia](https://en.wikipedia.org/wiki/Language) under CCASAL 2021 **Teeth:** These can be carved in-situ to provide identification of office or status with primitive tools: [![enter image description here](https://i.stack.imgur.com/r38HH.jpg)](https://i.stack.imgur.com/r38HH.jpg) British Museum via ZME science 2021 **Bones:** Bones can be carved to a texture and have been for thousands of years, some of the earliest Chinese writings are to be found in the "[Oracle-Bones](https://www.britannica.com/topic/oracle-bone)" found in various hoards, translated hundreds of years later by scholars. [![enter image description here](https://i.stack.imgur.com/SHzSW.jpg)](https://i.stack.imgur.com/SHzSW.jpg) Cambridge University library, via Britannica 2021 Perhaps kept in great libraries, perhaps in personal collections, perhaps each skeleton tells the history of it's owner, the writer certainly has options. **Hair:** The [Quipu Writings](https://www.ancient.eu/Quipu/) of the Incas are held on knotted string, though translation has been unsuccessful it is thought to have been one of the earliest forms of information retention system. [![enter image description here](https://i.stack.imgur.com/v8W7n.jpg)](https://i.stack.imgur.com/v8W7n.jpg) Unattributed commercial website savacations . com [Answer] If they have underground caves and water, they can make clay and use it as substrate for writing. Not much different than what was done in Babylon, where vegetation was scarcer than clay. The walls of the caves could be engraved with permanent writings. If any of their fauna produces anything similar to wax, they can also use it. And if they want something durable there is still parchment or its analogue. If you have easily accessible written media literacy will be more widespread than if you shut your books in libraries accessible only to the elites. In Pompei one can find graffiti written by low classes, and paper was yet to come back then! [Answer] Human civilizations made by with spoken word for mass communication for millennia. It is not perfect for recording, but if a few elders in each community know how to read, they can read aloud anything deemed important enough to the culture that everyone should know it. More niche knowledge that does not need to be known by everyone can be sought out and read by individuals. [Answer] ## Without Flora, Mass Literacy is Irrelevant Flora is fundamentally necessary for nearly every technology known to man. No flora means no wood or fossil fuels for fires. Without fire, you can not have metallurgy, ceramics, or mortar. Even many of our products we can make from animal parts need fire to process them, like hide glue and leather. Flora are also used directly to make things like textiles, wicker, tool handles, etc. In short, without fauna, your planet will be stuck in the early stone age LONG before there is enough information worth sharing to need to worry about how you will write it all down. [Answer] ## Democratize the walls If the walls and other surfaces are the best place for writing, then perhaps "wall rights" are an important property right. Perhaps, in the past, families reserved large areas for keeping records, and they pass them down through the generations. It would be interesting to re-read parts of your family history while feeling for a clean space to start writing. Or, perhaps each troglodyte is granted an allotment in the Great Hall of Writing as a sort of universal basic right. Perhaps the size of the allotment is based on wealth or social standing, where well-to-do troglodytes get large allotments at a comfortable writing height, while lower-class troglodytes get allotments on the floor or up high where they need a ladder to reach. If each allotment were regular in size (say, built out of 1 meter squares), allotments could be assigned an "address" describing its location in the large hall. A troglodyte would know his or her writing address as well as an American may know his or her social security number. [Answer] **Textiles** **EDIT:** Noticed the post explicitly prohibits flora. I can't imagine how you would have complex fauna without flora, but I believe the reasoning stands even when you only have animal products. If there is enough food, there are textiles. On earth, many lifeforms that provide us with food also provide fibers that can be spun into yarn. If there is enough life to eat, there is likely also enough life to create textiles. (plus textiles are generally very useful to a society and are [among the first technologies we have developed as humans](https://en.wikipedia.org/wiki/History_of_clothing_and_textiles)) Textiles can support rich patterns: [![https://commons.wikimedia.org/wiki/File:Constantine_Slaying_the_Lion_(tapestry)_-_1637.jpg](https://i.stack.imgur.com/u4GoT.jpg)](https://i.stack.imgur.com/u4GoT.jpg) [![https://commons.wikimedia.org/wiki/File:Crochet_sweden.jpg](https://i.stack.imgur.com/ZYLfc.jpg)](https://i.stack.imgur.com/ZYLfc.jpg) And they can also be quite thin and storable. We usually create patterns on textiles by combining yarns/threads of different color. Your societe would use textiles of different material/structure/thickness to let the patterns be appreciated by touch. If you get to industrial level, you can [mass-produce patterns on textile](https://en.wikipedia.org/wiki/Jacquard_machine) which could in fact be quite similar to printing press! ]
[Question] [ In the process of developing an ocean world setting for my fiction, I have often pondered whether to give the sapient species of the world access to some form of wood or other resource from underwater trees. I would like to know you thoughts on how plausible underwater trees would be on an earth-like ocean planet, what would they be like and what features, resources and threats would they have? Consider expanding your definition of trees for this question, I simply mean some large roughly vertical plants that fulfill the role of trees, even if you can picture them looking and acting nothing like terrestrial trees. [Answer] ## Mangrove Madness & Floating Islands: Is your entire planet Ocean, or are there islands? [Mangroves](https://www.conservation.org/stories/11-facts-you-need-to-know-about-mangroves?gclid=Cj0KCQiA0fr_BRDaARIsAABw4EuylTqTsvvr_iEpCiLthNR0kjOehryngsDtIpU5q6MXoByw7ZMVKvYaAjb7EALw_wcB) are a source of wood that is intimately tied to the sea. While it is not DEEP sea, many species are dependent on mangrove salt-water "swamps" for critical parts of their life cycles. It would likely fill the role you are looking for, allowing a sea-faring species access to wood, and might also provide an intermediary environment where sea and land species might come together in either competition or cooperation. The problem with wood is that most aquatic plants don't find it necessary to support great weight against gravity, or have a reason to anchor resistant structures against the power of the currents, so buoyancy is the simple solution to keep a plant up. If you don't have islands, perhaps there were once islands, and there is wood preserved under the sea. My understanding is that wood is sometimes [stockpiled in deep cold water](https://www.custommade.com/blog/underwater-timber/) to preserve it until needed. So some might be legacy wood. A fun alternative might be to have a floating tree ecology. Ancient trees got around extinction by forming a floating platform of interconnected trees, almost like a grown ship. Perhaps some land animals or bird species take advantage of these structures to live on or lay eggs. There are certainly species of birds today that essentially never land and fly over the sea for months at a time unless laying eggs. The guano from the birds provides nutrients for the trees and carries seeds for sub-species of plants on the island. I imagine a species of Jelly fish that lives by hanging off the bottom, pulling up fish and other creatures to eat amidst the roots and providing a nutrient-rich supply of remains for the trees (plus protection from predators who might eat their roots), while the trees provide a home and safe haven for the jelly fish. The trees might have a distillation method to produce fresh water if desired (although over time they would likely tolerate salt better and better, but this could help support the floating island biome). The jelly fish and surface environment would mean your people could get wood, but you can make that as challenging for them as you want. It could be common, or a rare and valuable commodity. [Answer] Corals are not exactly plants, but they are alive and can be grown with enough patience. They have a variety of shapes, textures, densities and toughness'es. You might also consider some sort of fungi. [Prototaxites](https://en.wikipedia.org/wiki/Prototaxites) were prehistoric phalic fungi that could grow 1m (~3.3 feet) wide and 8m (~26.2 feet) tall. They were also very rigid too (they were quite vertical, which required some rigidity). In your world there could be even larger, underwater variants. Your aliens could harvest these for their equivalent of wood. ]
[Question] [ I've been toying with the idea of a world that was once hyper-technological, where body modification and nanotech-based body modifications were the norm such that society practically couldn't function without these various enhancements (similar to current society with smartphones). Only, *something* caused the collapse and ruin of said society. Cut to many generations later, where much of nature has reclaimed the world. Certain systems, such as nuclear power plants, were designed with such redundancy that they have managed to continue operation until now, with the assistance of some mutated post-apocalypse folks being advised by an AI that has helped them with the operation of said facility. However, being post-apocalyptic, they have none of the enhancements that the people operating the facility would have had, and thus would not have the full capability of the original facility workers. As a result, the facility is very gradually declining to the point where failure, potentially catastrophic, is imminent. My question is, what would a group of 3-6 people who were preserved since before and thus have said enhancements be able to do that could prevent the full collapse of the facility and prevent a potential radiation leak/nuclear explosion? I'm stumped thinking of what exactly they could do differently [Answer] ## Interfaces Think of how many different modern devices now use Bluetooth connections and smartphone apps to control them. Extend that further, and the various controls and diagnostic displays in the plant all were built with the expectation that the maintenance techs will have their own Augmented Reality system that they can use to view the outputs and send commands back to the system. The main control panels have visual displays for redundancy and the AI is of course monitoring everything as well so the plant can still be operated, but in order to perform detailed, specific maintenance, you need to have the interface augments that the system was built to work with. The AI is smart enough to identify that, say, Pump AX-1 is operating at 72% capacity, but can't identify that it's because a compressor seal in it is wearing out. The AR interface would let a maintenance tech accessing the pump see its full technical specs, pull up the complete maintenance log for it including when all of the seals were last replaced, the expected life cycle of those seals, the replacement part numbers, etc. And even if the AI *could* identify that the compressor seal was failing, it wouldn't have the step-by-step instructions available for how to disassemble the pump and replace it. Since the post-apocalyptic crew doesn't have those augs, they either have to replace broken components from an increasingly-depleted stock of spare parts, or figure out patch fixes, kludges, or workarounds that clear the error that the AI is reporting. So the post-apocalyptic operators are making do with bare-minimum fixes that are slowly eroding the safety margins and failsafes that the system was designed with. Once someone is able to properly access the maintenance interfaces, they'll be able to begin the process of getting the reactor back up to spec, if it's still possible at that point. [Answer] **Make the advanced nuclear plant such that you can achieve what you want for your story.** The advanced plant does not have to be Chernobyl or Three Mile Island. This is advanced tech! A fictional self sustaining power plant can be whatever works for you. You can make it what you want, retroactively creating the plant setup to accommodate the sorts of actions that will help your story. For example suppose it is an air powered fusion plant. If the heat of fusion is not captured and turned into electricity there will be runaway heating and the possibility of huge explosion. Your characters cut off the fuel supply to the fission reaction and it goes out. Or if your reaction is run by fissile elements you could have a character heroically trundle in there and separate the fuel rods manually, counting on enhancements and protective gear to keep her alive long enough to finish the job. [Answer] DRM (digital rights management), or some other access control interface. Whatever fix is required needs someone to interface with a console that requires permissions or some sort of certification. People certified in Managed Power Atomic Assembly systems get a special module that authorizes them to access these consoles (you don't want just any Joe Schmo doing so, right?). The console itself can't be cracked by the AI (not an authorized user), and the society doesn't have the industrial base to make a replacement. [Answer] **They can't... unless...** Unless there's a whomping large amount of self-repairing automation in the world that's still functional. High tech ***requires*** a massive dependency tree that starts with raw materials (lumber, mining, agriculture, education, population) that extends through tool-making, transportation, and a thousand other things and ends up at your nuclear facility. To put it another way, the reason your facility is breaking down is because that dependency tree no longer exists... ...and you just asked if 3-6 people could fix it. **Sure they can...** If the issue affecting the facility is one that can be fixed without outside resources, like maintaining software or providing that special "nanite" interface (like a DNA match) that allows the nobody-remembers-it's-there security override to not shut the entire facility down because the right person isn't in the right place at the right time. *Aaaaaand that massive dependency tree is either handwaved away, ignored, or is fully automated so as to not be the problem.* **No they can't...** If they need outside resources, something from the dependency tree, because that tree requires a tad more people (think "hundreds of thousands if not millions depending on the level of the tech") than just 3-6. **TL;DR** So, to make this happen you need to ignore the dependency tree and come up with a non-resource solution to your problem. Such as... * Equipment calibration/maintenance (like replacing a bad sensor or realigning something that I don't know squat about because I'm not a nuclear physicist — maybe it requires math that no-one at the time of construction would ever think would need to be integrated into the software since it was available to everyone, like having an old [HP41CV](https://en.wikipedia.org/wiki/HP-41C#The_HP-41CV_and_CX) in your backpack. *Mine was on my hip and had a name, I figured any calculator that smart deserved a name.*) * Software/database maintenance * An internal resource shift (like moving the old control rods out and the new control rods in, but this is a short-term issue. Eventually you'd need new control rods.) * Talking down the suddenly [much-to-in-control-AI](https://www.youtube.com/watch?v=h73PsFKtIck), which won't respect anyone who doesn't have the 400+ IQ the nanites would give them. * The software starts to respond in a now-dead language that the nanite-people have instant access to. [Answer] For that you need to have a good understanding on how nuclear power-plants work, how they evolved/changed in your world, why would this dudes even need special upgrades to run the facility when an AI dictates their actions and what aspect of the building is crumbling and endangered. You have a concept idea but without this details there is not much to work with. ]
[Question] [ Don't you just hate when Euron injures your pet dragons and perforates your fleet with a ballista? Don't worry, all you need is a shipful of Wildfire and a very long fuse (or Mehdi Sadaghdar with electric equipment) onboard. Lay back, play some music and watch the [ensuing light show](https://www.youtube.com/watch?v=fuNyWMAWptE&feature=youtu.be&t=103). But how does Wildfire even work? ## What we know so far Wildfire is a neon green liquid that's stable at room temperature, but is very easy to ignite with just about any spark or flame. Wildfire, stored in a closed space, tends to cause enormous explosions, while out in the open, it simply burns with a green flame. Wildfire can't be extinguished with water and continues to burn for quite some time. It is also said that it can burn hot enough to melt steel beams. **Assuming no magic is involved, how could Wildfire work?** [Answer] We can deduce a few properties of the mixture from its observed behaviour: 1. **It's a hydrophobic, glutinous gel** over a wide range of temperatures. There are lots of chemicals which match this description. 2. **It's self-oxidising**. The mixture doesn't require external oxygen from the air to release energy; this is necessary in order for it to explode when confined. Gunpowder, [ANFO](https://en.wikipedia.org/wiki/ANFO) and thermite are all good examples of this. 3. **It burns with an extremely high temperature**. If it's capable of at least softening steel beams to the point of failure, it must be able to reach temperatures of 1250°C plus. There's a smaller range of reactions that kick out that kind of heat, but still plenty of examples, like white phosophorus (2760°C) or aluminium-iron-oxide thermite (2500°C). 4. **It's green**, both in base colour and in flame. There are a couple of metals and salts that could be contributing to that. For my money, I'd suggest that wildfire consists of a mixture of a thermite powder dissolved in a glutinous fuel-oxidiser which contains something like barium chlorate as the oxidizer. The leftover barium burns with a green glow which is [very similar](https://commons.wikimedia.org/wiki/File:FireworkatDisneyWorld.png) to the colour of wildfire in the video. The fuel-oxidiser provides the initial heat to start the thermite reaction which can then reach the extremely high temperatures. If the oxide in the thermite was [chromia](https://en.wikipedia.org/wiki/Chromium(III)_oxide) instead of iron oxide, you would get the potent green colour in the base mixture as well as in the flame. Chromium itself burns with a silver-white flame which would add the white tints seen in the wildfire. [Answer] It seems a more potent version of gasoline. It might have a higher viscosity, and hence a slower evaporation rate, but otherwise behaves very similar. When gasoline is enclosed and ignites, it will explode quite spectacularly. This is because only the vapours ignite, and burst the container throwing the rest of the gas everywhere fine enough to ignite as well, resulting in a fireball. But when gasoline is ignited on a surface the vapours on top burn off, but the rest isn't flung anywhere so it will burn at evaporation speed. It is also hydrophobic. If the burning temperature is high, then it would be hard to douse with water. The water won't cool it quick enough, and the hydrophobic quality means full coverage is hard to achieve. The green flame might be a company signature, they could lace it with boric acid or copper sulfate. "If its green, its quality". ]
[Question] [ I am developing the global context about my game and I realize that I only developed one nation. I want to show the planet as a unit to counter against the divine side *(there is a kind of strange plant God)*. But the question arose if it is possible that something like this existed, as humans we always tend to divide ourselves, which makes me want to add one more nation. What should I do? [Answer] By definition, it is impossible for an entire world to be ruled by a single nation. A nation is defined as a large group of people who have many cultural factors in common and are culturally different from people who are outside the group, and who feel that they are a nationality or ethic group or nation separate from all other groups. So by definition a national government rules over a territory occupied by a majority that are members of one national group, plus usually members of a few minority groups. And if ever a nation manages to lose all members of minority groups, because they successfully revolt against that nation, or because they are exterminated, or all emigrate to other nations, or all gradually assimilate into the majority, that will not last. Even if some nation achieves a population with 100 percent majority nationality, that will not last forever. Over time minor differences between different segments of the population will grow larger and larger, and people will care more and more about those differences, until the people of a once homogeneous nation now feel like they are members of two or more ethnic groups and nationalities instead of one. If there is a government ruling over an entire planet with a population of hundreds of millions or billions, it is likely to rule over tens or hundreds or thousands of ethnic groups who all consider themselves to be separate nationalities and nations, and thus be much more like an empire than a nation. If the people of that empire feel loyalty to it, that loyalty will be more like imperialism, empire loyalty, than like patriotism, loyalty to a nation. [Answer] There were times in our own history when "the world" really seemed to almost be taken over by a single nation. Every time it was a bunch of people who were under the banner of one empire that was as wide as its denizens thought to be the whole of the world. Yet not a single one got to dominate even just all places inhabited by people. They would just call those outside their domain "barbarians" and call it a day. Some examples of such empires and their rulers: * The Greek under Alexander the Great * Medieval Europe under Charlemagne * Medieval Europe under the pope as well, as popes had power greater than kings for a long while * Asia under Kublai Khan So maybe it comes down to your world having some imperialistic nation that went on a roll conquering others, but they don't have the technology to map the world much beyond their borders so the head of state thinks they rule the planet alone. [Answer] Humans tend to divide, unless confronted with a sufficient Other to bind us together. You say there's a divine plant thing that needs balancing. A plant with deity powers sure seems like a motivation for humanity to band together. Now, the real question is time period. The world being under a single government is conditional upon one key thing: speed of communication. If you cannot communicate the will of the central authority out to the tips of the empire (and get replies back) with regularity and speed, the empire will fracture. At various points in time, new communication techs appeared and the average size of nations increased in those times. The US central government in Washington became significantly more involved in California with the advent of the telegraph, for example. So, yes, single world government appears to be plausible given human history, but only with a sufficient threat to band us together and with communication infrastructure to bind us under one flag. [Answer] As humans, we do have a natural tendency to divide "us" and "them" when it comes to social groups. I remember reading somewhere (some time ago, not sure if I can still find the exact article) that while humans are social creatures, we are adapted to small social groups and tend to get overwhelmed by huge crowds such as those found in metropolitan cities. That is why there is that tendency to think that people get "colder" and more distant the larger the city gets, because they retreat and keep to themselves more as a defense mechanism. You didn't specify the species, but I believe it would be better if you created beings that are naturally evolved to live in large cooperative societies, with less defensive instincts among their own kind that would lead to possible infighting, and ideally some sort of evolutionary pressure that caused them to prefer collectively relying on each other for support and survival. It should be easier to form a global government with less risk of fracturing then. ]
[Question] [ Bringing a human child to term generally takes place over a period of nine months. They are marked by different stages, from 1st to third, and are marked by different events and expectations for mother and child. While no two instances are the same, this process is generally similar enough to be predictable. Babies are generally in the womb for the same amount of time. In an alternate world, women are regularly with child for more than a year, with the most extreme verified case being more than three. The "average pregnancy" lasts, about nine months, but comes with a "plus or minus six months" qualification. Because of gestational periods being more unpredictable, it becomes essentially impossible to determine when any given child will be born. Standard deviations are quite large, with any one individual having multiple several prrgnancies with various gestational times. This has no overall effect on the child itself. What alterations to the biology of a species would lead to this development taking place? [Answer] To form a "ready-to-be-born" baby one needs to follow a series of steps starting from the fertilized eggs. Therefore in that sequence there is no room for variation, if you want to stay within a single species. What can influence the duration of the pregnancy would be the capability for the woman to put the development on idle under certain circumstances. For example, a period of low food intake would stop the fetus development, so that the mother can more easily survive it. The development would then restart as soon as the food supply is back to normal. As a consequence the apparent lenght of gestation would be different from mother to mother. [Answer] L.Dutch's answer would lead to a predictable result--less food, longer gestation. Instead, there is a trace element the body needs that is in limited supply. Shortages are common enough that the body evolved to limit fetal growth to the supply of this trace element rather than suffer deficiency problems from it's lack. Required trace elements have been found well into the 20th century (when IV nutrition became possible we saw previously unknown deficiency diseases) and there are still disputes about whether certain elements are required or not. Thus even a 19th century society would not know about these trace elements and not understand why some babies came faster than others. [Answer] Human gestation periods were originally keyed, I imagine, to environmental factors, with an optimal strategy of conception in late spring, brooding through the winter months, and birth in early spring. This is a typical pattern for creatures on an estrous cycle, at any rate, because it gives offspring the most favorable conditions for survival in their first days. That predisposition likely carried over into the menstrual system that higher primates use. So, one simple way to get wide variation in gestation (strictly through evolutionary adaptation) is to remove the seasonal variations that produce an environmental selective force. On a planet with a nearly circular orbit and negligible axial tilt, there would be no advantage to a gestation period of any certain length, so gestation length would be uncoupled from any time dependency. Natural variations in the length of gestation would accumulate in the genome, because no offspring would die off from being born 'out of season.' There would be some natural lower limit based on the minimal time in which a fetus can develop to a viable form, and some natural upper limit, likely based on the maximum size for a baby to pass through the birth canal. But within those limits there would be a bell-curve of 'natural' times based on genetic predispositions and other factors. ]
[Question] [ 2019 sucks. I'm going back to the Renaissance -- specifically, Florence Italy in the year 1503. I've never been that great a planner, but I should think ahead at least a little. **How do I earn a living in 1503 Florence?** Better yet, how do I become rich? I speak both Latin and modern Italian, so I figure I'll muddle through on the language side. I'm getting pretty fed up with the present, but I can probably spend a couple months learning a new skill if needed. I'm a 19 year old male in pretty good shape. My crazy great aunt said I'll be the first one to test out her new time machine, and that I'll probably show up naked. She isn't quite sure how it will deal with paradoxes (she isn't exactly filling me with confidence here, but $%#@ the present), so I should do my best to avoid changing anything major. That means things like changing the course of a war or introducing too revolutionary of an invention (though I figure something mundane enough is probably fine) are all out. --- Answers will be judged on certainty of outcome (marrying a Medici would be great, but I can't exactly count on that happening) and potential payoff (I could probably get a job as a day laborer, but that wouldn't make me much money). Unspecific answers are no good. I thought about betting on Palio races, but couldn't dig up any winners from that long ago. If your answer requires knowledge of a specific event, please include resources for me to find that knowledge. [Answer] **Gambling** While a bad advice in current times back then statistics wasn't a well developed field of math. Exploit the "seat of ones pants"-methodology of the time. Use modern knowledge to figure out which bets have a positive expectation and spread the risk as wide as possible. You would win & lose the same bets as everyone else and follow to the rules to the point, so you shouldn't be serious suspicion of cheating. The main benefit here is the low entrance barrier. A few coins earned through day labor and a place to play at. You can expand that by advancing to bookkeeper once you have sufficient cash reserves. Once you have enough money you can build a reputation and establish yourself in the more elevated layers of society. **Trading** Modern knowledge of financial math,logistics and economics are a major asset. Being able to gauge how good a map is by comparing it to what you remember of the modern days is certainly a way to reduce the guesswork and thus increase profit margins. Both have the benefit of putting you above average in terms of performance while being plausible deniable. **Profiles of the field and the players** Don't get caught up in any of the everyday problems of the time. Early in your new life that is something mundane as disease. Later it becomes vital to know who the powerful and ruthless figures around you are and what the try to archive. Septic shock from a minor scratch? An embarrassing end. Being a pawn in the crossfire between the noble houses? The wrong kind of exciting. Etiquette helps to a degree, being aware of how prevalent syphilis was(and how to avoid it) might be wise as well. Basic first aid and emergency procedures as well as understanding of actually working "natural remedies" are invaluable. [Answer] > > I speak both Latin and modern Italian, so I figure I'll muddle through on the language side. > > > Sorry to disappoint you, but modern Italian is far from being intelligible to a Florentine dwellers of 1505. I mean, I can read a letter from Galileo or Leonardo da Vinci and with some effort make sense out of it, but I would never be able to fluently speak in that way without some training, and I am pretty sure I would sound rather odd to their ears, too. And Leonardo or Galileo were literate people. And Latin will help you talk with the learned, but not with common folks on the streets. So, you start off being naked and talking in a funny/odd way. How can you become rich with this? For starters, rule out arts. Yes, you are in a good place full of artists and protectors, but first of all you will have a fierce competition (like popping up in an NBA team and expecting to be in the starting 5), and even if you are exceptionally talented, artists back then struggle to reach the end of the month. I would say study economy and accounting and seek employment in a bank, applying your knowledge to increase the profits of the bank. Once your efforts and successes will be noticed, you will start climbing the social ladder and end up negotiating with kings and popes. As usual recommendation to time traveler, master hygiene and get ready to face Montezuma's curse. Also keep record of all the pestilences sweeping the land in those times, and plan your vacation accordingly. [Answer] Your primary requirement in that period is just to survive. Your modern person's understanding of hygiene and infection control will carry you a long way here but there are other factors to consider: # Swot up your history Specifically the house of Medici and their on and off relationship with Florence at about your period. > > The exile of the Medici lasted until 1512, after which the "senior" branch of the family — those descended from Cosimo the Elder — were able to rule until the assassination of Alessandro de' Medici, first Duke of Florence, in 1537. This century-long rule was interrupted only on two occasions (between 1494–1512 and 1527–1530), when anti-Medici factions took control of Florence. - [wikipedia](https://en.wikipedia.org/wiki/House_of_Medici#16th_century) > > > Now some could say that you're in a lot of trouble and you should leave Florence before the wars start. However I'm going to point out that times of upheaval are also times of great opportunity. It's during these periods that Machiavelli rose to prominence in the city, before being exiled of course. All you have to do is pick the winning faction, that you have the advance knowledge of knowing is the Medici, and ally yourself with them in some useful way. If you get it wrong and end up allied with the republic, you might be lucky and merely be executed. On the other hand you could also try joining the church, you can read and write so you're off to a reasonable start, but without political allies (powerful family) don't expect to reach especially high office. However the church was among the richest and most powerful organisations in the world at this point and there's plenty of opportunity for personal or familial gain as demonstrated by the political play around the high offices. [Answer] **Find treasure troves identified between 1503 and today** [Wikipedia](https://en.wikipedia.org/wiki/Category:Treasure_troves_of_Italy) lists 6 treasure troves found in Italy, I am sure there are more if you investigate a bit more. Research the finds, in particular go to the site of the find in the modern day and make sure you can find them. Go back in time, find them and sell them. [Answer] There's a bit of a problem reconciling *getting rich* with *not changing history too much*. How much of a problem will depend on your definition of "rich", but going from 2019 to 1503 means that your standard of living is going to take a pretty large hit no matter what you do, and getting closer to a 2019 standard will cost increasingly large amounts of money. Sure, you could be modestly prosperous by 1503 standards without necessarily disrupting timelines too much. But if you're hoping for Medici-level wealth then you will become a major player in society no matter what you do, and disposing of your estate after your death or departure will be an issue as well. So depending on your expectations for wealth, and your degree of concern about altering the timeline in major ways, various options will be more or less attractive. But an option that you could probably employ relatively safely would be to **use modern knowledge to provide goods or services to the wealthy of 1503 in a more cost-effective way than would otherwise be possible at that time.** As long as you keep your knowledge to yourself, you'll retain your advantages over others in 1503, and after you die or depart the 1503 standards will not have advanced. There are any number of ways you could do something like this, and they offer differing levels of involvement and dependency on your part. But by limiting your activities to direct services of the wealthy, your alterations to the timeline may well be subsumed by the wealth of your clients/patrons. For a couple of easy examples: * A modest knowledge of modern hygiene and medicine would allow you to identify and treat or prevent diseases otherwise incurable. If you were to grow your own cultures and harvest your own penicillin you could be a miraculous concierge doctor in 1503 without actually needing much medical knowledge. * A couple of freely-available textbooks or case studies could teach you loads about operations management, process efficiency, and statistics which was not known in 1503. This would allow you to be much more productive (or make workers you oversee more productive), have higher-average-quality outputs, though you'd need to choose the applications carefully. * A small amount of technical knowledge could allow you to produce ludicrously expensive or valuable goods with far less effort than others. If you know the Bessemer-Kelly process, you can produce high-quality steel centuries early and create high-quality metal products. * A bit of historical geographic knowledge could let you "discover" caches of historical curiosities that would be valuable to wealthy people. Greek culture was popular. Many more examples exist. But these are the sorts of things that society in 1503 *already* valued highly, and by being irreplaceably good at providing those things you'd be able to carve a nice portion of already-existing wealth off of the rich and mega-rich for yourself. And if you spent most of that income back into your local economy your presence wouldn't necessarily even alter very much. [Answer] If you're 19, then you've probably finished high school. Hopefully you were paying attention in math and maybe even physics class. If so, then you know some calculus and Newtonian mechanics. Now spend a few months studying these subjects very carefully. This knowledge alone should make it easy for you to become the best engineer of the time. Find somewhere where you can sign up as an apprentice and work your way up. Which will happen very quickly. You probably don't want to go sharing the secret of how you get your calculations, though, if you don't want to cause any big changes. [Answer] You could risk medicine as you know some basic things like washing hands is good and utilizing the bile of ones own body is always bad for curing health issues save maybe foot fungus and blood letting does nothing. Knowledge of modern techniques will save more people and gain you more reputation but being that the witch hunts were also still ongoing on in parts of Europe you best understand what is considered good and bad prescriptions to hand over. You may have knowledge to make some basic home remedies but this could also be viewed as witchcraft. Blacksmithing can also work they will have a far off need for it going forward and since you know the modern end result we have welding, we have metal twisting, we have unique designs you might be able to create a ye old version of goods they couldn't imagine gaining you reputation and better contracts. ]
[Question] [ I have seen in this site that there has been constant attempts to make a working **Plasma Gun**, only to be constantly met up with failure, as shown with my post regarding Warhammer's Plasma Cannons. However, one redditor came up with another suggestion, saying that it would be better if the plasma came in the form of bullets instead of coming out of the muzzle by themselves. This is what he says: > > The most common weapons are plasmas. Essentially railguns, plasmas launch small pellets of helium-3 enclosed in ferrosilica shells that create explosively-formed penetrating jets of plasma on impact. The "ammunition" for plasmas consists of a magazine with separate storage chambers for helium-3 and ferrosilica powder, which is spray formed into a thin shell ballistic template in the receiver, flash-forged by the addition of helium-3, and rail-launched. Long guns, handguns, and scatterguns, particularly those used by military forces, can generally accept the same magazines, and spent magazines can be replenished at ammo depots. While most of the helium-3 goes into the ammunition, some of it is consumed directly in the weapon to power the firing rails, optics, and internal systems. Larger ship-mounted plasmas have their own reserve tanks of helium-3 and FS powder, which can be replenished from centralized stores deep within the hull. The necessary resources for plasma rounds - helium-3, iron, and silicon, can be easily found in space. After firing, without impact in 5-60 seconds (depending on size) the pressure of the gases inside will rupture the thin shell, which will burst harmlessly. Plasma are rugged and reliable, if comparatively lacking in power. Large enough plasmas can overwhelm or even bypass defense matrices. The ballistic template, which controls the shape and thickness the shell, can be modified to produce various kinds of secondary explosive effects, from armor-piercing to incendiary to EMPs. On the civilian end, low-powered plasma weapons with limited payloads make effective less-lethal weapons for self-defense or riot control. Higher powered plasma cutters and furnaces that contain plasma in magnetic fields have a number of mining and industrial applications, but their military use is limited. > > > What are your thoughts? Just how do we make a plasma weapon that works as it should? And if this doesn't work, feel free to make a suggestion on another Plasma Weapon that should. PS: *It seems that "Plasmas" is the name of his weapon, not the plasma by itself.* [Answer] **Vortex Plasma thrower.** [![vortex flame cannon](https://i.stack.imgur.com/6fq9H.jpg)](https://i.stack.imgur.com/6fq9H.jpg) <https://hackaday.com/2018/04/18/fire-vortex-cannon-need-we-say-more/> Plasma is hot - like gas but hotter than gas and more reactive. By its nature it will want to expand to fill a large area with glowing ultra hot matter. If you are a sniper that is not too useful. But there are circumstances in which it could be useful. A plasma vortex will roll out huge glowing rings that expand as they go. This plasma will look like flame; possibly too bright to look at. As the vortex entrains atmospheric air in passage, that air will also be heated to flame bright. The plasma vortex is an anti drone weapon. Drones are hard to hit with projectiles because they are small and fast. It is easy to run out of ammo trying. The plasma vortex uses air plasma as its ammo and produces a large field effect. This gun will stop firing only if it runs out of energy. Because the vortices rise, multiple shots can produce a vertical area of denial. As opposed to projectiles there is less possibility for collateral damage from the plasma vortex when used in a built up area like a city. Sometimes windows break if you can pin a drone against a building with a plasma vortex. Plastic drone parts hit by the plasma vortex will melt and malfunction. At higher altitudes, the vortex (mostly just hot gas by then) is much less dense than the surrounding atmosphere, and the drones lose lift, fall and tumble. A second shot at closer range will cook them. --- The developers of the plasma vortex gun were not pleased to see their device used for riot control but it works well. If you are a rioter, a cloud of flame rolling over you will not kill you. You can see it coming and you will close your eyes. But your clothes might catch fire, hair will definitely catch fire and you will get first and possibly second degree burns on exposed skin, if you are foolish enough to go rioting with flowing locks and your face showing. Mostly it is really scary to have a swirling wall of flame bear down on you, and it is enough to cause all but the most devoted rioters to flee. [Answer] I think this would count as I am proposing very very high rotation rates and very high electric charges. The gun could utilize some immensely strong materials formed into a small perfect disc shape. This disc would then be given a very large electrostatic charge, positive on the rim and negative in the centre or vice versa. It would then be spun up to an extreme rotation rate such that the materials strength was more or less overcome and it was only held together by the electrostatic charge across its surface. This projectile would then be ejected from the gun using electrostatic repulsion and or gas pressure. On hitting the target the equilibrium of the disc is disrupted and all the rotational and electrostatic energy pent up in it is released creating a small cloud of plasma out of the disc and its immediate surroundings. [Answer] A 1990 era series of experiments known as [MARAUDER](https://en.wikipedia.org/wiki/MARAUDER) (Magnetically accelerated ring to achieve ultrahigh directed energy and radiation) was conducted by the USAF with the purpose of creating a plasma device capable of being used for > > “hypervelocity projectiles,” x-ray production, and electrical power amplification. The stated goals of the program included studying the “formation, compression, and acceleration of magnetized plasma rings.”[3](https://i.stack.imgur.com/5KB0f.jpg) > > > Specifically, the objective of the program was the acceleration of a toroid of 0.5-2.0 mg plasma to a kinetic energy level on the order of megajoules using a 5-10 MJ coaxial gun design.[3](https://i.stack.imgur.com/5KB0f.jpg) > > > The program was classified in the mid 1990's and has essentially dropped out of sight since then. Details are scarce, but it seems that the intent was to create a high density "smoke ring" of plasma that would retain its cohesion through internal magnetic fields (i.e. be self supporting) and accelerate the plasma smoke ring to velocities approaching 3% of the speed of light. At that speed, the kinetic energy alone would be on the order of 2kg of dynamite, and the plasma would also induce: > > rings of plasma and balls of lightning exploded with devastating thermal and mechanical effects when hitting their target and produced pulse of electromagnetic radiation that could scramble electronics, the energy would shower the interior of the target with high-energy x-rays that would potentially destroy the electronics inside.[5] > > > Unfortunately, the main reference is a very short Wilkipedia article, which only provides very limited understanding of what the USAF was trying to achieve. The reference to using the Shiva Star capacitor bank to energize the experiments suggests that any "real" plasma weapon will be a huge energy hog, so plasma pistols or rifles would be well outside of the bounds of possibility, and even vehicle mounts would require massive generators or capacitor banks to operate. So far as I can tell, what is being described in the OP's post could be "macrons", essentially tiny blobs of matter small enough that they hover between the boundary of individual molecules and macroscopic matter. A recent post on "[Tough SF](https://toughsf.blogspot.com/)" discussed this, including how various forms of macron accelerators might work. "Nuclear" macron rounds might be achieved by essentially filling a "buckyball" (C60 shpere) with frozen deuterium and slamming it into a target at 100km/s, triggering a fusion reaction upon impact. While a single macron with a microgram of D2 would only register as a pinpoint flash, a stream of hypervleocity macrons could create a large fusion reaction (and plasma) so long as the rounds are impacting a hard target. This would also be rather large (like a metalstorm launcher with multiple barrels) and would really only work well in the vacuum of space. [![enter image description here](https://i.stack.imgur.com/5KB0f.jpg)](https://i.stack.imgur.com/5KB0f.jpg) *A macron launcher would resemble a volley gun* So there are at least two "real world" concepts of a viable plasma weapon out there, but their practicality is limited by size, energy requirements and the need to fire physical projectiles in a vacuum ]
[Question] [ **This question already has answers here**: [What species of animal could take over earth if humans went extinct?](/questions/99818/what-species-of-animal-could-take-over-earth-if-humans-went-extinct) (13 answers) Closed 4 years ago. I'm considering creating a world which take place on earth after all humans are dead/gone (we don't care actually). In this situation another/some other species develop enough to be a civilization. As I'm far from an expert in animals, I actually don't know what could realistically be the "next human". So hear I am with my question: "What species has the most chance of becoming the next civilised species?" [Answer] In short term (millions of years), most likely already long living, somewhat intelligent and social species with free hand-like manipulators. In longer term (hundred of millions years), pretty much anything can change. So, in order of decreasing probability: * Genetically engineered (uplifted) animals with hands. Monkeys, apes, maybe hamsters, ferrets, mutant polydactyl cats... Or ab initio created animals. If your scenario allows this. * Naturally evolved hominids, or perhaps even lesser apes (orangutans, chimpanzees and gorillas might be already in an evolutionary cul-de-sac, intelligent, but too specialized and rigid). * In longer terms, evolved bipedal rats (they are pretty intelligent and social already), other rodents. Dogs, dolphins, elephants and some corvidae are quite intelligent but do not have hands (and no clear evolutionary way to get them). * Some aquatic non-mammal species (octopoda) are intelligent and possess manipulators, but they are rather antisocial and of course their civilization would have enormous problems to get to any reasonably high technological level. * Insects etc. have rather low probability to become intelligent, they are quite static and limited by missing lungs. Hive minds are sci-fi. [Answer] I think next pretender would be some ape, orangutan maybe. They some of necessary things to create something of civilization. Apes have dexterous hands, quite big brain, can use tools, have social lives. On Earth we have also other smart and/or social animals, but most of them lack something essential. For example dolphins are very smart, but their fins and environment doesn't promote using tools or especially fire. Other example are any collective bugs, like ants or termites, they have very well organized society, that can achieve astonishing feats, but they are more then hundreds of millions years around, so if there would be any chance to evolve to some civilization, they've had already done it. [Answer] Some type of monkey, likely an ape (since they're better on the brain front). But it's not just brains that you need. I don't think it's possible to overestimate how important hands are for our civilization. Boiled down far enough, any tangible result of science is just advanced tool use, and our hands are unmissable for how we are doing that. Almost as important as that is the use of fire. If fire hadn't been as important, than octopi might have as good or better a shot than apes do. Dolphins would also be a candidate in that case. [Answer] Since your query specifies a *civilised* species, rather than a species possessing intelligence, awareness, soul, imagination and the like, I'd posit that such species already exist. Or are very close to it. A civilised species should have, according to human definition, a highly developed society or culture; refinement in taste and manners; or evidence of moral and intellectual advancement: humane, reasonable, ethical. I'd argue that humans are pretty consistent with the first definition, okay with the second and rather spottier with the third. A random sampling of "hallmarks of civilisation" reveals certain characteristics: * Advanced Cities * Organized Central Government * Complex Religions * Job Specialization * Social Classes * Writing * Art and Architecture * Public Works Let me introduce you to the humble termite! Already (and for millions of years), termites have built advanced cities containing housing, gardens, central air conditioning, roadways & public infrastructure. They have an organised central government of the strict monarchical model. They have job specialisation and a social caste system. Their cities are wonders of architecture and design that younger species are beginning to learn from. We do not understand their communications or their minds, so we can't say for certain about things like art and religion and writing. Clearly, even without these elements, two of which even uncivilised humans possess, termites are actually pretty civilised. For a look into what fully civilised termites might be like, I'd suggest *[The Termite Queen](https://rads.stackoverflow.com/amzn/click/com/B007RFYSWC)*. [Answer] Among mammal species, there are a small percentage with bodies large enough to support large brains. Among mammal species with bodies large enough to support large brains, a minority do have large brains, brain comparable to human brains in size. That leaves about a hundred or so species of mammals on Earth with brains, and possibly intelligence levels, comparable to that of humans. they include at least four, and possibly more, ape species, three surviving species of proboscideans, and about 90 species of cetaceans. So it is possible that between zero and all of those species are advanced enough to count as people. But none of them are civilized. All of the ape and elephant species use and even make tools, since they have good manipulation appendages, but the cetacean species have only their tails, flippers, and mouths to hold tools, which some of them have been observed to do. The cetacean species also have the disadvantage of their aquatic environment to hinder developing civilization. So if humans become extinct, any surviving species of apes or elephants, that might possibly already be intelligent enough to be considered people, would seem to have the best chances among mammals of developing a civilization soonest. ]
[Question] [ I need help in figuring out how to form an air force in the roman empire. In my story a time traveller goes back in time to ancient rome and becomes emperor and begins his attempt at modernizing the legions. I would prefer if no magic was involved, other than that all ideas are accepted. [Answer] The only "airforce" that can be plausibly created in a lifetime of time-traveler are **incredibly expensive hot air ballons** and **extremely dangerous human-lifting kites**. Both used for reconnaissance and communications. But it's just not worth it. They would be just expensive toys with minimum applications. * Selfpropelled planes - definitely no. There was no light and powerfull power source. Those "steam turbines" were highly inefficient and heavy (made from bronze). * Gliders - maybe, but unlikely: unlike kites, they require stronger, more durable low weight materials, just to not fall apart in a midflight (nothing saying about landing). And, most important, they require extremely high for that time period crafting skills, to make that glider symmetrical and balanced enough to be stable at flight. And even if romans manage it - it will hardly lift one human and will have aerodynamic quality (glide distance divided by start height) less, then modern parachutes. And it can't be used for any military purpose (if not turned into kite) Roman military mashine was perfect for that time period and region - it had nothing to improve. And the only challenge it had was itself. Civil wars did more damage for Republic and Empire than any enemy did. [Answer] As I have commented on other answers I do not think any traditional form of aircraft is viable for the Romans. They would need to bootstrap hundreds of years of advancement in materials science, metallurgy, mechanical knowledge, tooling and machining, mining etc. to produce any kind of engine, and not much less than that to make a hot air balloon. That means we have to think outside the box. **Wooden gliders** Very situational, high risk of being shot down or just landing in an inconvenient place. Would require a nearby hill or mountain for a gravity-powered launch. Maybe you could [launch one](https://en.wikipedia.org/wiki/Gliding#Launch_methods) from a ballista or tow it behind a team of horses? Seems like this is nothing but a liability though - and you might be better off just firing the ballista (or horses) at people. **Well-trained animals** Get pigeons to drop hot coals on the enemy. Bat-bombs. Release a swarm of mosquitoes and give the enemy malaria (biological warfare!) Angry war hornets. Launch rabid squirrels from catapults! Hm, now I think I'm getting off-topic. [Answer] The time traveler shows them how to build steam engines and how to create electrical power. Then he shows them that steam engines are much better than slaves for many applications. Then the time traveler announces he will sleep for 20 years to restore his godlike powers, and he will come back looking exactly the same. The time traveler uses his time machine to jump 20 years into the future from his current point. He looks how far the romans have advanced and guides them some more, then he skips time again. Once the first steam engine was built things moved fast in the real world, there even where steam powered planes: <https://en.wikipedia.org/wiki/Steam_aircraft> The hard thing our time traveler has to figure out is how to skip ahead to allow technology to advance and still remain emperor. [Answer] Powered flight would be extremely difficult, if not impossible in Roman times even if they had instructions. The primary difficulty would be the power plant which would require precision engineering of a sort that was not present in ancient Rome. Advances could be made but progress would be slow as so many required technologies would be needed the absence of each slowing the overall development down. Things like metallurgy, machine tools and electric power to name few. It might well be possible to build gliders with detailed instruction, a lightweight wooden frame and stretched fabric skin. And they might even fly given enough time, effort and lives, but it is debatable if this would constitute an “Air Force”. Such craft would be very easy to damage and cumbersome to move around. It is unlikely they would be of much use during most battles, but might find some application. If a city was under siege in a hilly or mountainous area such craft might be used to overfly the city and drop flammable materials or fire bombs. It might even work (although the danger of setting the glider alight would be a significant hazard). That said ballistae would probably be much easier, the real advantage of the glider would be as a brightly painted terror weapon. Hot air balloons might also be possible made of paper or better still with silk, however paper is relatively heavy and silk was a very rare and expensive luxury item in Rome. Had such a craft been made it might have served as a tethered observation platform, but the practicalities of such an arrangement would have been dubious. A [fire balloon](https://en.wikipedia.org/wiki/Fu-Go_balloon_bomb) might have been slightly more practical as a terror weapon in some circumstances (although still at the mercy of the wind) perhaps for use inside a city during a siege. Wait for the right wind direction then loft some large paper balloons with highly inflammable payloads and a long cord. Let them drift over the enemy and then ignite and release the payload. So in summary, a “proper” Air Force would not be a practical proposition, however some air based weapons might be developed. How practical they would be and whether they would constitute an Air Force are debateable. [Answer] [Paragliding](https://en.wikipedia.org/wiki/Paragliding) and [Parasailing](https://en.wikipedia.org/wiki/Parasailing) could be options, especially because most cities (read: most military targets) would be near an ocean or river, where boats (with the right wind conditions) could be enough to get parasailers in the air and steering in the right direction. For areas near mountains or cliffs - where "near" could be a few miles away - paragliders could be trained. Working and stable parachutes could be made from animal skins - albeit imperfect and dangerous by modern standards. Warfare in Roman times often included besieging cities (where gliders could fly over the city walls), or meeting in large groups face-to-face in fields or hills (where gliders could route over bridges, rivers, or even simply group up and throw arrows from the sky). This would require defenses that were sealed *above* - digging ditches or building walls would not be enough defense. Furthermore, calvary would be vulnerable as they could not easily hide from the arrows raining from above, as foot solders had different shields. This type of basic "air force" would give a significant and plausible advantage simply because of [it's asymmetrical tactics](https://en.wikipedia.org/wiki/Asymmetric_warfare). [Answer] The obvious answer is to do hot **air balloons**. But if your character is creative and has some historical interest, he could take inspiration from the first human propelled planes which were basically **gliding-bikes**. Bikes are a must have for your kind of story anyway (revolution of transports for the common people, can be used on Roman roads...), the emperor would just use a special one for his daring friends. Also, if you aim to modernize Rome, you should seriously consider the invention of the radio. Though the Hertzian waves, the voice of your emperor could spread through the whole empire, protecting the borders from foreign aggressions would also be significantly easier. [Answer] Your best bet for an aerial force would be to use balloons. The [Montgolfier Brothers](https://en.wikipedia.org/wiki/Montgolfier_brothers) Figured out how to make balloons out of paper and were able to lift fairly substantial amounts firing them with a variety of fuels. So you do not necessarily need silk or refined fuels to make them reliable devices to get up in the air. The best way to use these wonderful things is for observation and for sniping! Tether the balloons to control where they go and allow them to get high enough out of archer range. From here, you have some options. Since you are tethered, you can rig a simple message system to raise and lower messages from the observers and Commanders on the ground. Use your technology expertise to make sure the balloonist and ground crew have reliable compasses. That way you can direct fire from Balistae and catapults. Heck, attach one balloon to each heavy weapon and they can begin firing at an enemy the ground crews can't even see. Sniping, in a generic sense is another thing your balloonists can do. Get an excellent archer or crossbowman up there. They will be high enough that they should get some extra range from the bow. It's always a good thing when you can hit the enemy from far away. You might even be able to arrange some other nasty surprises for the enemy, like throwing pots of oil like molotov cocktails across enemy lines. So even though you probably won't get powered flight, you can still have Roman Aeronauts doing a lot of things for you and they will even be able to shout: **Mors Ab Alto** ]
[Question] [ Assuming a turtle or tortoise evolved adaptations to become large comparable to that of sauropods. How large could they become (in weight or potentially carapace size)? The turtle needs to be primarily terrestrial. Adaptations: * Hollow, honeycombed bones (including shell) * More efficient lungs like that of birds * Metabolisms comparable to those of sauropods. [Answer] Not bigger as they were (up to couple of meters in diameter). Or they will stop being turtles: * *Hollow, honeycombed bones (including shell)* are the worst armor - they can be easily pierced or crushed. Yes, Apollo spacecraft was basically made of "honeycombed foil" and survived reentry, but could be pierced (and was once) with a screwdriver and crushed with a hammer. This makes the shell totally useless as a protection against predators. And predators of that time had knife-like teeth and jaws strength of 0.5-2 tons. * *More efficient lungs like that of birds* - this would not help *turtles*. They would not be able to use "bird" lungs because they cannot breathe with their ribs (because their ribs are solid shell). Breathing is not the thing that dictates turtle size: marine turtles take a breath only once in 15 minutes (or more) - and still bigger than terrestrial ones. * *Metabolisms comparable to that of sauropods* - that will totally remove turtles main evolutionary advantage, which allowed them to survive through 2 (two) major extinction events (no other group of species of large animals did). And having high volume and low surface, compared to sauropods turtles would have to *reduce* their size not to boil alive. Just look at stegosaurus - how hard it was trying to increase its body surface! It all means that with these adaptations turtles would **de**evolve to something more crocodile-like, as they were at the start of their evolution. You do not need a shell, if you can run fast - it will only slow you down! But if you look for giant "animal tanks", look at [glyptodont](https://en.wikipedia.org/wiki/Glyptodont) (real giant armadillo). First homos were using their shells as homes! Both this, and the largest terrestrial turtle were about the same size (about 2 t weight and 2-3m length), and I don't think this is just a coincidence. It is the limit for biologically created shell to be strong enough to provide reasonable protection. The larger they get - more fragile they become (square-cube law). [Answer] The book and TV series "The Future is wild" postulated gigantic tortoise which would fit the bill easily: the [Toraton](https://speculativeevolution.fandom.com/wiki/Toraton) [![enter image description here](https://i.stack.imgur.com/wdsns.png)](https://i.stack.imgur.com/wdsns.png) *Toraton* > > The Toraton is an enormous tortoise from the Bengal Swamp in 100 million AD, in the documentary The Future is Wild. > > > In an environment such as the Bengal Swamp, where vegetation flourishes, the presence of large herbivores is no surprise. The largest of them by far is the Toraton. > > > The Toraton is by far the largest member of the ancient tortoise family, which dates back to the Pliocene epoch of the Neogene period. Since 220 million years or so before the human era, in the Late Triassic period, their order has thrived. Their basic shape and lifestyle were so successful from an early stage in their history that they hardly evolved. Now, 100 million years past humans, conditions have encouraged a huge increase in their size, enabling them to exploit the incredible mass of vegetation that now exists in this greenhouse environment. > > > The Toraton is a cold-blooded reptile, so it does not face the problem of overheating that would confront a similarly-sized mammal. > > > With an average body weight of 120 tons, this is the biggest terrestrial animal known ever to have walked Earth, more massive than even the greatest of the known dinosaurs, the sauropods, though some particularly large dinosaurs could have achieved a body weight similar to or even greater than that of the Toraton, possibly rivaling or even exceeding the Blue Whale, the heaviest known animal. > > > So given the proper environment, the humble Tortoise has the potential to reach astonishing sizes if it moves into the niches once occupied by giant herbivours like sauropods, elephants and so on. The only other feasible way to become larger is likely to go the other way and become a completely aquatic sea turtle, and take the niche of baleen whales straining plankton from the ocean. Of course, what sort of predators exist in the ocean to justify a shell of that size? [Answer] I see no problem for sea turtle being as big as modern blue whale. They would only need to develop [ovoviviparity](https://en.wikipedia.org/wiki/Ovoviviparity) as they can't go back onland to lay eggs. No big deal. ]
[Question] [ In my fantasy world I have a humanoid species that can work pretty much non-stop. Assuming he has enough energy, can one of these creatures do most of the necessary things on a 25 meter long cog to sail it successfully? There would usually be about 4 other people on board who are competent at sailing, so they could help out when extra hands are needed, but could the tireless creature and maybe one or two others do the bulk of the work, or are there too many stations to be manned? I haven't done much research about ships yet, so I don't know what all the different tasks on board would be, but the purpose of the ship would be either for traveling or transporting cargo. [Answer] From the real world, a sloop the size of your "cog" can be singlehanded for long voyages, even circumnavigations. The reason I specify "sloop" is because the rig is designed to be easy to sail; the number of controls is minimized with only mainsail and jib (you wouldn't bother with a spinnaker in this situation, and they're generally only used for racing anyway). The tiller or wheel can be "lashed" when the captain/pilot has to leave the cockpit to change the set of sail, and for long ocean legs one will often hold the same tack for hours at a time anyway (you get the same effect if you sail fifty kilometers and then tack forty as if you sailed ten five kilometer legs and ten four kilometers ones the same headings). By the late 19th century, there were even "autosteer" rigs using a wind vane to manage the tiller and keep the wind on the same point, allowing the singlehander to get a short nap without going adrift. [Answer] Speaking as a sailor, if we're talking a 75-footer on medieval technology, the answer is "not really." Even with the aforementioned four unskilled hands to pull line, there are tasks requiring skilled hands both managing the sails and the tiller. And in a storm, all bets are off: you need a skilled steersman on the tiller *at all times*, and people who know what they're doing around to deal with other tasks. In shallow waters, you need a leadsman to boot. In fair weather, light winds, calm seas and deeper waters with light traffic, sure, you probably could manage. Anything else, that's a recipe for disaster. ]
[Question] [ I write sci-fi, and I don't love fudging important things. I have a character that was a victim of genetic experiments (I know how original). I want to find a semi-reasonable way to explain this.(not just the experiments but also the powers she got from them) her developing pyrokinesis as a result of the genetic experiments isn't accidental, the scientists that worked on her intended for that to happen but didnt expect the strength and or the range of her abilitys to be what they are/were. [Answer] Any scientific explanation of pyrokinesis should start with a definition. As usual, [wikipedia](https://en.wikipedia.org/wiki/Pyrokinesis) provides... > > Pyrokinesis is the purported psychic ability allowing a person to create and control fire with the mind > > > ...from that article, a useful initial premise arises... > > Parapsychologists describe pyrokinesis as the ability to excite the atoms within an object until they generate enough energy to burst into flame. Science fiction works define pyrokinesis as speeding up the movement of molecules in order to increase temperature. > > > So we want to create a character whose mind can excite atoms at a distance to the point of combustion. Atoms usually get excited when thermal energy, such as heat from an adjacent fire, is applied to them. Depending upon the substance being ignited, the amount of thermal energy does not need to be very high. Gasoline fumes for example, only need a spark. So let's make the job easy for our character, beginning our explanation with some real world possible sensory enhancements which allow her to sense the presence of easily combustible compounds at a distance. Since sharks can reportedly smell a single drop of blood at many miles distance, I don't think anyone will complain if our little fire starter can smell and precisely locate her favorite volatile substances at 20-30 feet. From there, it is just a small step to light the proverbial match. If your fictional world already has telekinesis, then the mechanism for that match already exists. Your fire starter is just a telekinetic who moves energy instead of matter. Stealing enough heat from the surrounding matter and focusing it on the volatile target is all it takes to get the process started. If your world doesn't have telekinesis, you can explain her ability away by saying that it is still telekinesis, which remains impossible at anything above the energy level. None of this will give your character fireball throwing abilities. For that, you probably need to focus her telekinesis down below the atomic level, allowing her to split a few otherwise stable atoms to release the required heat. Giving her that much power however jumps the shark in a big way, leaving you with every little that can threaten or challenge your character later in the story. Fireballs also don't make a lot of sense strategically. Why throw it at a target when you can just create it inside their skull, bypassing their defenses. Without the subatomic energy boost, your character will still have a considerable range of abilities, depending mainly on what combustible compounds are nearby. She will also have very useful limitations which can help in your story creation. If you can be satisfied with a super hero who can set an enemy's clothes on fire rather than incinerate them, then these ideas should make it look like you are at least trying to play within the laws of physics. It is still not science because at its' core, it is still dependent on telekinesis which has not yet been scientifically proven. But beyond that fundamental flaw, a pyrokinetic character, created using these ideas, could be a physical-law-abiding member of your otherwise real world. ---EDIT--- After posting this lengthy answer, I re-read the question and realized that I answered the wrong part. The OP was not looking for an explanation for the pyrokinesis, but rather for why a normal person would be subject to generic engineering. I can't bring myself to delete my previous work, but I will address the actual question here... If you open up your definition of genetic engineering to include GMO foods, cutting edge antibiotics and performance enhancing sport drugs, then almost all of us are subjects of genetic engineering in one way or another, every day. We also all live in the same genetic soup, breathing each other's breaths and potentially trading genes with every touch. Add to that the UV radiation from sunshine and pollution from every imaginable source and it is a miracle that we aren't all super-powered mutants and pyrokinetics. [Answer] You specify your character underwent genetic experiments. How does that happen in the real world? Perhaps your character was experimented on in the context of a **clinical trial**. Your character might have been born with a genetic disease. There are many. Ornithine transcarbamylase deficiency is an example, and there are clinical trials looking at genetic modification of people born this way in hopes of overcoming or sidestepping the disease. <https://clinicaltrials.gov/ct2/show/NCT00004498?cond=ornithine&draw=2&rank=5> Or perhaps she has a childhood cancer like a brain tumor and undergoes experimental gene therapy or infusion of her own genetically altered T cells to treat the cancer. As opposed to "experiments" done out of malice or some perversion, you can have the experimental procedure done in hopes of helping her, and it actually worked - she was cured of her illness. But later there are consequences. And she was not the only participant in this clinical trial... [Answer] The condition [Hypothyroidism](https://www.hopkinsmedicine.org/healthlibrary/conditions/endocrinology/hypothyroidism_85,P00412), an under active thyroid gland, can cause [Hypothermia](https://www.mayoclinic.org/diseases-conditions/hypothermia/symptoms-causes/syc-20352682) or low body temperature. In an attempt to treat the symptom of low body temperature, scientist used genetic engineering to alter your character. They gave her the ability to speed up the atoms in her body to produce heat on demand to warm herself. However, your character eventually discovers that she can speed up the atoms of anything that she can see and focus on, that is located in her general vicinity. This would give her the ability to set things on fire from a distance. [Answer] There is a scientific rationale for a person developing pyrokinesis because of a genetic experiment. Assume that in this fictional world effectively everybody, human beings that is, have the genetic capacity (or at the very least the genetic basis for those powers) for them to have pyrokinetic powers. However, this capacity is not expressed, because of a genetic blocking factor. The genetic experiment unblocks the innate biological mechanism repressing her pyrokinetic powers. *Viola!* She now develops her pyrokinesis. [Answer] **Random Chance.** We might be able to work out the gene associated with something to turn it on and off but we mightn't know all the genes involved. The scientists know the gene to give the ability but what they didn't know is the person carried other genes that affect the strength and range which in a person without the ability, they lie dormant. ]
[Question] [ The humanoids I'm talking about are designed with all the characteristics pertaining to robots developed with the help of soft robotics technologies. Although the skeleton is made of titanium, their "muscles" are produced from soft multi-material actuators. There's a network of nanosensors forming a substitute to human sensory receptors. The only thing I haven't yet come up with are **heating elements**, which will **give warmth of a normal human body** and at the same time **won't melt delicate synthetic materials**. Can anyone give a clue what sort of material can be used here? Can it be an alternative of human vascular system (as my humanoids can work on biobatteries, so this energy can be distributed by "vessels")? The warmth is a key feature for humanoids in my world, because they work with humans and sometimes for humans providing elder care services or medical care. [Answer] The material of your heaters is irrelevant. Running the right amount of current through any resistor will heat up the material. Heaters can be made thin, flexible, all it needs to have is slightly higher resistance than the leads going to the heater. What matters is that anything else can stand 37° Celsius, which is not that exotic. Any standard plastic will do, there are very few plastics being commonly used that can't stand 37°, since you can reach that on a hot summer day. [Answer] They'd probably produce enough heat and be heat conductive enough to not actually have a problem but if we assume we need to fake it... I'd have a dense mesh of infrared LEDs and sensors under the skin. This would essentially (with some processing) give the robots the ability to see all around them with reasonable accuracy. This would allow them to accurately avoid embarrassing accidents. They'd know if somebody is standing behind them or if something is the path of their arm or if something is where their foot is about to land. They'd even "see" what is in the box they pushed their hand into without having to look. It would also give them a finely controllable infrared source, so they could give a precisely tuned experience of warmth directly to your skin without having to waste energy to warm themselves. Also, and this is actually an answer in itself without complex and expensive IR systems, simply make their skin have low heat capacity and conductivity. A surface like that will actually have the exact same temperature as your own skin when you touch it. If you are human and the aim is to make it feel the same as human temperature, this is exactly what you want. As mentioned this is actually enough to make them feel right. The IR system is only needed if you also want to mimic the way you can sometimes sense nearby human body heat. [Answer] You will need the skin to be warm, for the very reason human skin is warm. And it will have nothing to do with 'feeling like a human', and certainly no need for heating elements. No matter how your muscles work, they will produce heat. Same for all of the electronics in the AI and the nervous system. This heat will have to be dissipated, for the same reason computers need to have cooling fans. I could see the mouth and nose working as cooling vents for fans, but I doubt that would be enough. Your best bet would be something like the [liquid cooling and ventilation garments](https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation_garment) readily available for human use. They would circulate the coolant (water? robot blood?) through the muscle fibers and electronics, to collect the heat, and then circulate it to the cooling tubes on the surface (or just below the surface) of your robot skin. There would, of course, be no need for seams or openings. It would probably be an all one piece suit. ]
[Question] [ It’s 2019 in an alternate steampunk/dieselpunk universe. Population growth, dwindling resources, and the evil overlords have everyone cramped into big cities, toiling away in the hope of something better. For now though, it’s enough to just complain about the weather. Smogs are a frequent occurrence, you really don’t want to breathe in the air, and to top it all off, sometimes it rains oil. The ground goes all slick, the walls have this slightly weird rainbow-y sheen, and it’s enough to make anyone think twice about heading outside if they can help it. So: **how can I get it to rain oil?** I was thinking initially about strong winds/hurricanes that lift oil into the clouds, and then they fall down again, but I have no idea if that’s a reasonable suggestion. I’d like it still to rain normally, but this seemed like a way to still get oily ‘rain’. If that’s not feasible/if there’s another way, I’d be up for suggestions! The technology level is anything industrial level or later, but no magic. Also, I’d like it be to habitable for humans if at all possible... *EDIT:* Forgot to mention the kind of oil I was aiming for - probably something petroleum based, but definitely something used in a manufacturing process more than an organic or culinary kind of thing. (However, I admit I don’t know a grand deal about oil, so you’re welcome to argue the point if extra virgin olive oil is where I should be focusing my efforts). [Answer] ### Lots of airships. [Oil mist](https://en.wikipedia.org/wiki/Oil_mist) consists of micron-sized particles of oil suspended in the air. It can be produced in a variety of ways, but in general, it's aerosolized lubricant from a mechanical device. It's a fairly common hazard in machine shops, and a significant enough hazard on ships that all ships with engines over 2250 kW must be equipped with detectors. In a steampunk world, with overly gratuitous airship traffic, perhaps those airships are creating enough oil mist for it to collect in the atmosphere and rain down to Earth. This could be due to either standard mechanical negligence, with old and leaky engines producing much of the mist, or perhaps because the safest way to handle oil mist on an airship is to vent it out into the atmosphere and rely on it diluting out to non-explosive concentrations. Either way, the oil mist is gathered into clouds where it rains down as part of an otherwise-normal rain storm. It's unlikely that sufficient oil would be present to become an acute fire hazard, but it wouldn't be difficult to imagine that enough would collect to make the ground slick and give everything a nice oily sheen. All it would take would be enough airships. [Answer] It wouldn't be pure oil but it could be usable with some processing: Have airborne oil producing plankton. The bloom in clouds because of the condensed water droplets. They might make even more clouds by being condensation nuclei. The plankton takes in water, CO2, trace elements from dust, and sunlight. It uses that to produce oil. The oil forms a film on the water droplets and increases their surface tension. I don't know if the surface tension would increase the chance of big drops forming or decrease it. However, that coating would make the rain drops shimmer in the sunlight. That may be a good visual for your story. The drops that fall will be mostly water but if you can separate the oil out, you get your oil. So, you have slightly green fluffy clouds that get much darker green (going to black) that then rain shimmering drops. Come to think of it, trying to use windshield wipers would suck with the constant oil film. Hmmm... Cumulonimbus: giant lightning broccoli. [Answer] **Siloxane pollution.** [Siloxanes](https://en.wikipedia.org/wiki/Siloxane) are silicon oxygen polymers in the silicone family, slippery and volatile. The silicon sounds exotic but siloxanes are in lots of consumer products, like shampoo and personal lubricants. Depicted: Decamethylcyclopentasiloxane. [![https://en.wikipedia.org/wiki/Decamethylcyclopentasiloxane](https://i.stack.imgur.com/RYgP8.png)](https://i.stack.imgur.com/RYgP8.png) > > Cyclomethicones are a group of methyl siloxanes, a class of liquid > silicones (cyclic polydimethylsiloxane polymers) that possess the > characteristics of low viscosity and high volatility as well as being > skin emollients and in certain circumstances useful cleaning > solvents... Cyclomethicones have short backbones that make closed or > nearly-closed rings or "cycles" with their methyl groups, giving them > many of the same properties of dimethicones but making them much more > volatile. > > > Siloxane pollution is a thing in the real world, and these molecules move from the many commercial products containing them into the environment. <https://cvskinlabs.com/7-cosmetic-ingredients-that-are-bad-for-the-environment/> In your world, there are some big sources of atmospheric siloxanes - I was thinking scavenged or repurposed alien tech, or possibly building treatments to protect against pollution. These volatile siloxanes condense or precipitate out under the right conditions, forming a greasy Astrolube-like rain. I like siloxanes for this question because in the siloxanes are real, useful, do form atmospheric pollution, are oils, and the words "siloxane" is good stuff for scifi. Also to my knowledge it has not been done. [Answer] Not normal rain, at least not in a world humans can live on the the vapor point of oils is way above boiling, if the air is warm enough to hold oil it is hot enough to kill any human who breaths it. your best bet is tornado lifting, but that will be a regional and fairly rare occurrence. ]
[Question] [ Dwarfs are intelligent creatures, with stronger bones and muscles but smaller than humans. They live mostly under ground (caves, mines, etc.) and reproduce sexually. How long the gestation period would be for a female dwarf? Dwarfs were hunted by creatures that fed mainly on them and had to adapt to overcome that (animals at the bottom of food chain usually have a small gestation period) [Answer] If you are assuming that your dwarves are still primates, you can make use of the following chart, relating the gestation time (in days) with the weight (of a fully grown female in kilograms) for primates ([source](http://www.applet-magic.com/gestationi.htm)) [![Gestation duration vs weight chart](https://i.stack.imgur.com/n8XsB.gif)](https://i.stack.imgur.com/n8XsB.gif) Which can be fitted with the relationship $\log(Gest) = 2.075 + 0.189 (\log(Wt)) $ Estimate the weight of your dwarves, and get the fitting gestation length. [Answer] Gestation time in great apes varies from 240 days to 280 days on average. Not a huge range given hte size difference between the largest and smallest members, bonobos and gorilla. So anywhere in that range is fine. The longest gestation time is not gorilla but humans (the range is 240-260 days without humans) so you may want to favor the high end of the range, something about large brains favors longer gestation. ]
[Question] [ I want to know if the disease I invented is logical or just a total fiction. A parasite (parasitic fungus) lives within the human brain. It infects other humans by releasing spores while invoking states of rage within their hosts. This makes it easier to infect other humans as it's similar to a "zombie" virus, if you will, though they're not dead. (I know there isn't any parasitic fungus which can infect humans, but let's say a new species was found or created in this story.) The peculiarity of this parasite is that it can only infect people who are over 25 years (or thereabouts). Why? Because the brains of the people who are under 25 (on average) haven't reached the fourth age, so the parasite isn't viable. The frontal lobe in particular is the important factor, because to be viable for the parasite it needs to be fully developed. There are five brain ages: * 1st age: during pregnancy. The first neurons are formed from the 28th day of pregnancy in the embryo. * 2nd age: from birth to 12 years. * 3rd age: from 12 to 25 years old. (The regions in the frontal lobe are getting fully developed in the mid twenties.) * 4th age: from 25 to 65 years old. * 5th age: from 65 years old to ... Oh, and if a vaccine could be found, in what way will it be the most effective? So, do you think this parasite is possible or completely unrealistic? If you have any suggestions or ideas to make it more realistic, I'll gladly read them. [Answer] A plausible explanation could be that a fully-developed frontal lobe is required to breed the virus to the point where the brain is overtaken. Instead of drawing a hard line and saying that it can only infect people at 25 or over, it'd be much more natural to say that it's incredibly rare to be infected below that age range. A vaccine doesn't sound doable with modern medicine, since your virus presumably takes control of the person's entire body, including motor functions, choice, etc. Not only would this make them not want to take a vaccine, but the only real vaccine that could exist would be to full-on cut out the frontal lobe before the virus expands too far. So you know, it is /sorta/ possible for a human to live without a frontal lobe, but that kind of virus probably shouldn't be out there. Hope this helped! [Answer] **The parasite lies dorment in wisdom teeth.** [Wisdom teeth usually emerge sometime between the ages of 17 and 25.](https://www.mayoclinic.org/diseases-conditions/wisdom-teeth/symptoms-causes/syc-20373808) They have that name because their emergence generally coincides with maturation, with adulthood. Wisdom teeth are unique because there is only one set of them. For all the other teeth, there are baby teeth (which fall out between the ages of 4 and 13, depending on the placement of the teeth and with some individual variation) and permanent teeth. None of the other teeth work for the parasites because the baby teeth fall out too soon and the permanent teeth are buried under the baby teeth for the first few years. Most people are infected as children but the parasite doesn't cause any symptoms when in the dental pulp. It is not until the wisdom teeth emerge that the parasite is mature and able to migrate to the brain (up the back of the throat to the nasal cavity then, with some burrowing, it finally reaches the brain). There is no vaccine, but early removal of wisdom teeth (still inside the gums) is a pretty good preventative. Is this scenario realistic? No, not particularly. But it has the right timeline and might help you sell your storyline. I hope it is useful to you. [Answer] **Persons 25 and younger were (inadvertently) vaccinated against the brain fungus.** New vaccines are periodically rolled out. For example the chickenpox (varicella) vaccine came out in 2005 and subsequently in countries where kids get vaccinated, kids were vaccinated with it. In addition to immunity from chicken pox (or whatever the target is of the vaccine in your story), a side effect of that vaccine is that it also conferred immunity to a fungal contaminant in its manufacture. The fungal contaminant is related to the dementing brain fungus. Persons who received that vaccine as children are therefore immune to the brain fungus. Upside - you have a hard date between which people are immune and not immune. You do not have to posit a hard difference between the brains of 23 year olds and 27 year olds. Downside - unvaccinated infants are not immune. Persons in 3d world countries that do not use the vaccine in question would not be immune. Antivaxers would not be immune. ]
[Question] [ In my story, humans have colonized both a high-G and a low-G world in the same star system. How would surface vehicles have to be designed differently for practicality and economy on each of those worlds? World A (Yanacocha) is a large [carbon planet](https://en.wikipedia.org/wiki/Carbon_planet) with surface gravity 2.12 times Earth. Theoretically, the crust of a carbon planet would be mostly graphite. The atmosphere is relatively thin (~44kPa) and primarily carbon monoxide, with potential for graphite dust storms, so I expect the colony to be mostly contained within sealed domes and tunnels. The primary function of the colony is mining. World B (Serana) is a smallish Earth analogue with surface gravity 0.7 times Earth. The surface conditions should be broadly similar to Earth aside from the low gravity and associated thinner atmosphere (about 68kPa at sea level). **Edit:** Added carbon planet link and details re: surface conditions on both planets. [Answer] **General** The majority of vehicle design need not change. This is because the *mass* of the vehicle remains the same, no matter what the gravity is. When dealing with the classic equation: $$F = mA$$ The effect of gravity is in the "A" (acceleration) term. When the gravitic force is perpendicular to the vehicle (when you're cruising down main trolling for a date Friday night), that force has no affect on acceleration. On the other hand, when you're ascending or descending a hill, a component of gravity is affecting your acceleration. But, in the end, it's just force, so there's little difference from modern design. But, of these differences, I can think of the following: * Fuel and coolant pressures will change moderately between gravities. However, this is easily overcome with a pressure regulator that consistently feeds the pressure appropriate for the engine despite changes in torque. This problem is already solved today (since torque and fuel feed already change when you climb a hill) using the engine's vacuum system. Basically, as vacuum pressure increases, so does fuel pressure or volume (depending on how the engine is actually designed). * Braking will change between the gravities, but again, only somewhat. The greatest problem will be the need for increased braking descending a hill on a high-G planet. Once again, modern tech already exists (via the ABS systems) to adjust both braking pressure and oscillation frequency to manage braking heat vs. braking friction. In the end, you'll use the same pads on both planets — they'll just last longer on the low-G world. **Friction Traction** **Braking** isn't simply pads on a rotor, it depends on the friction between the driving surface and the wheel or tread. This is affected by gravity. We could get into the process of calculating the coefficient of friction, parallel motive force, blah, blah. The problem is that it depends on *much more* than just gravity. It depends on the material of your tires, the material of the street, the angle of ascent at any given moment, the square acreage of material against the road, etc., etc.. Suffice it to say, if you have good tire rubber, you need more of it on a low-G world than you do on a high-G world to compensate for the change in gravity. Unless you're planning to lift-and-lower wheels, there's not much you can do here but change tire widths between planets. But, one-size-don't-fit-all here on Earth, so you should expect that. **Suspension,** on the other hand, is something you can do on the fly. If you were to design your suspension for the high-G world and try to use it on the low-G world, you'll find yourself bouncing all over the place. You could use a pneumatic suspension that adjusts the compressive force used for smooth driving by analyzing the weight (not mass) of a known mass (yeah, there's the mass). In other words, if your 1Kg mass weighs 4 pounds on your high-G world, the compressive force is increased by adding more air to the penumatic shock absorbers. That same mass may weigh only 1.8 pounds on your low-G world, thus air is removed. **Turning,** is a form of braking — we just don't think of it that way, expecially when Hollywood has been advocating that a constant acceleration through a turn will increase your final velocity. That's actually true (of course, it's true without the turn, too. Hollywood tends to ignore that part.)— so long as your tires actually remain firmly fixed on the road. Exceed the force of friction and you slide off the cliff, usually in a brilliant (if unexplained) fireball. The flaming tire bouncing into the distance is mandatory. However, while your vehicle's onboard computer is calculating the amount of air to force into your pneumatic shocks (and your air brakes, for that matter...), it can also be calculating now much to lean the tires into the turn, ensuring greater friction on the lower-G planet. **But what about hovercraft?** OK! Hovercraft don't touch the road, but (today) use skirts to hold a cushion of air beneath the vehicle. You have a propeller for motive force, but otherwise the same rules apply to the engine (although the operator is manually increasing the throttle rather than the engine vacuum system doing it. No friction on the ground, no increase in torque.). In fact, other than having to increase the air pump system to hold the unit up on the higher-G world and a bit more throttle on the prop to climb a hill, there's not much difference in how hovercraft would be handled. **But what about *real* hovercraft? You know, the stuff we haven't invented yet?** OK, you're not holding that hovercraft above the ground on a cusion of air, your riding the magnetics (hard) or using anti-gravity (harder). In reality (if that word can be applied to something we can't actually do in reality), it's all the same problems. More force toward the center of the planet to hold the vehicle above the ground and more force behind the vehicle to move it up a hill. **So, one size really doesn't fit all** No, it doesn't. The design of a dump truck is very, very different compared to the design of a scooter. The fundamental *physics* are the same, but the needs and purpose of each vehicle vary so dramatically that it's impossible to claim that one size could or should fit all applications. And since you shouldn't do it in real life, you shouldn't do it in your story, either. But, for the sake of argument, lets assume that your world is building a one-size-fits-all colonizing space ship. The Atlas Corp doesn't want to customize for every planet, they want to send the same thing to every planet (to manage costs). In that regard you might legitimately have a use for limited-design vehicles, in which case my suggestions apply. But there would be *so much* customization *anyway* that I don't believe it's practical to think about it. But, then again, I can believe that the tried-and-true bicycle wouldn't be different due to gravity. Two wheels, 1.5 inch wide tires, gears and brakes. The bicycle probably wouldn't change at all. [Answer] The question asks *how would surface vehicles be designed* on two exotic alien worlds; and the question asks for hard science. Unfortunately, [industrial](https://en.wikipedia.org/wiki/Industrial_design) and engineering [design](https://en.wikipedia.org/wiki/Industrial_design) are not engineering disciplines in themselves, but rather semi-artistic crafts. So I don't believe that a hard-science answer is truly possible, or else we wouldn't have seen, for example, the numerous weird and wonderful designs practiced during the ages here on Earth for bridges, from cantilever to suspension, or for surface vessels, from rafts and monoxylon boats to caravels and clippers. Nevertheless, a general answer *can* be provided. * Step 1: [Feasibility studies](https://en.wikipedia.org/wiki/Feasibility_study). First of all, we can safely assume that different organizations would be in competition to develop and provide surface transportation services for those worlds; and it is very likely that each of these organizations will attempt to develop several concurrent transportation modes, such as individual transportation for persons, mass people transit, transportation for small quantities of goods for deliver or supply, bulk transportation of goods, containerized transportation and so on. For each of the envisioned modes of transport, the organization will establish an exploratory group, tasked with elaborating a feasibility study. In order to elaborate the feasibility studies, each exploratory group will employ the services of a [project management team](https://en.wikipedia.org/wiki/Project_management) and a small army of [subject-matter experts](https://en.wikipedia.org/wiki/Subject-matter_expert) with expertise ranging from alien geology, to chemistry, metallurgy and the myriad subdisciplines of [materials science](https://en.wikipedia.org/wiki/Materials_science), including without limit, lubricants, plastics, glass and carbon fiber and so on. The results of these efforts will be a set of broad design guidelines, describing possible approaches for each of the transportation modes under consideration, or, in some cases, an indication that the specific transportation mode is not feasible. It is generally expected that the feasibility studies will also include broad estimations of the cost and effort for development, and an appreciation of the costs and revenue of operating the vehicles. Undoubtedly, some of the interested organizations, either very rich or very foolish, will attempt to perform this work in-house, while others will keep in-house only a core project-steering group and will farm out the work to various consulting, research and engineering organizations, such as universities, research institutes or specialized firms. Expect the development of each feasibility study to take one to five years, and cost on the order of millions or tens of millions of euros. * Step 2: [Prototypes](https://en.wikipedia.org/wiki/Prototype). The decision factors of each of the organization will then prioritize the results of the feasibility studies, will select one or two or four of them and assign each of those selected to a prototype design group led by a master designer. The prototype design groups will be given very broad requirements, flexible budgets and somewhat flexible deadlines; their task will be mostly to prove that it is indeed possible to design and build a vehicle along the lines of the vision articulated in the feasibility study, to identify engineering problems, and to find and explore solutions to them. Prototypes will be subjected to a sequence of practical tests and demonstrations, with the goal of dermining the limits and potential efficiency of each approach, so that those approaches which prove to complicated, too limited or too inefficient can be pruned out. Expect the development of each prototype to take two to ten years and cost on the order of tens or hundreds of millions of euros. * Step 3. Engineering and industrial design. Armed with the knowledge obtained from designing, building and testing the prototypes, the leadership of each interested organization will pick one or two or four of the prototypes as the basis for engineering and industrial design, with a view of moving them to production. At this point, the organization will begin talking to potential customers, in order to find out what their expected needs are, so that the engineering and industrial design teams will be given concrete requirements and goals; and this is also the point, if not earlier, where financing will definitely be sought, from investment banks, from investment funds, venture capitalists and so on. Generally, the industrial and engineering design work will be given to those enterprises which will actually manufacture the vehicles; it is not common, but definitely not unheard of, for railways or maritime transport organization to build their own locomotives and ships. During the engineering and industrial design phase, a number of production prototypes or concept vehicles will be developed and shown to potential customers and to the public; many practical tests will be performed, exploring the various engineering solutions identified during the development of conceptual prototypes; processes and tools will be developed and implemented, suppliers sought, contracts made and so on. Expect this phase to take two to ten years and cost hundreds of millions to possibly even billions of euros. * Step 4: Initial production. One or two or four of the engineering and industrial designs will the be put in limited production, with the goal of testing the market and performing final design adjustments. This is the point, ten to twenty-five years and billions of euros after the start of the overall project that the organization will find out whether their vision is successful or not. [Answer] While not as hard-sciencey as some other answers, I thought I would talk a bit about the considerations that may go into designing such a vehicle. I will say that designing a single vehicle to operate on both worlds is a bad idea. While a heavy-gravity vehicle will operate on a low gravity world, it will be hugely fuel inefficient compared to something purpose made, and shuttling vehicles between planets is unlikely to be practical anyway. So I suggest your vehicles are made on their planet of origin, for their planet of origin. I also suggest building refinaries on your carbon world - no point shipping ore offworld. Before I start, I'd suggest having a browse of [unusuallocomotion](http://www.unusuallocomotion.com). They have a great many weird and wacky vehicles that have been build by humans. Many of the images I link to here come from that site. **High Gravity Considerations** 1. The ground you are driving over has to hold the vehicle up, and prevent it sinking into the ground. On Wikipedia, you can find a [list of ground pressures](https://en.wikipedia.org/wiki/Ground_pressure). On a 2.12 gravity world, those figures will about double. As a result, An M1 Abrams tank will exert the ground pressure of a typical car would on Earth. And a typical car would exert a ground pressure somewhere between that of a mountain and racing bike. This says big things about getting stuck. Relativly normal things such as mud become a much larger obstacle. Yes, [M1 Abrams tanks do get stuck in Mud on earth](https://youtu.be/TCXwgPZXScM?t=84). They would get stuck twice as easily on World A. While Mud may not exist on World A due to it's composition, you would likely get sand, and you can (and will) sink into that. 2. Similarly, any pneumatic tire pressures will have to double to keep the same contact patch. This will require thicker sidewalls, stronger beads and so on. I'd say pneumatic tires would almost certainly be a poor way to go, because the same sharp rock will be twice as bad with twice the gravity. 3. You require more energy and torque to go up a hill. Think about how much more gas you require when going up a hill than on the flat. This will be worse on a high-gravity world. As a result, you'll have to carry more fuel, which weighs more, which makes your uphill performance worse. I couldn't think of a way to quantify this, but expect your vehicles to have many many low gears, and go uphill very very slow. 4. Much mass-mining equipment has great big crane arms. If a worlds primary industry is mining, I would expect to see giant equipment similar to, say, the [Bagger 288](https://en.wikipedia.org/wiki/Bagger_288). Unfortunately, these designs wouldn't work too well on a planet with double gravity. The strength of a beam goes up with the square, but the mass goes up with the cube. This applies to everything from cables on cranes (a free-hanging rope will break under it's own mass in half the distance) to the girders that hold things up. Everything will have to be smaller given known materials. You could almost assume that the largest equipment would be half the size as it is on Earth. I'd expect this makes profitable mining a bit harder. Where do we end up with this? I'd expect most of your vehicles to have tracks or fairly large tires. Airless tires would be a large contender. They'd move slowly, and the maximum size of your vehicles would be small. * For personal transport inside the city, I'd expect to see power-assisted bicycles. You'd have to pave the surface really smooth, but there's no reason they wouldn't work. A bicycle is much more practical than a car for an indoor city, and the light-weight of the vehicle with respect to the payload helps with the fuel usage. If possible, use airless tires, otherwise a modern racing bike tire can take really high pressures (a 200kg guy on a racing bike?). Bikes outside a paved surface would be virtually impossible. * For personal transport outside the city, I'd expect to see lightweight vehicles with large low-pressure-like tires. This could range from [large-tire dirt bikes](http://locomotionhorsnormes.e-monsite.com/medias/images/2wd-vasyugan-motorcycle-1.jpg?fx=r_950_950) which rely on low vehicle weight, to [rolligon-equipped cars](https://www.youtube.com/watch?v=Aav0z64SnB4) relying on large surface area. * For anything industrial, I'd expect to see tracked vehicles dominate. Tracked vehicles aren't common on Earth because they have lots of friction losses which necessitate low speeds. Because of the higher traction and lower ground pressure, I expect most equipment to be equipped with them. I think this is a photo-mash-up rather than a real vehicle (because this is the only photo like this anywhere), but you may well see vehicles like this: [![enter image description here](https://i.stack.imgur.com/SZKKW.jpg)](https://i.stack.imgur.com/SZKKW.jpg) It's relatively small (use in the background on the left), but has a huge amount of engine power and a huge amount of ground contact. You can imagine something like this dragging trailers out of a mining pit You may even see vehicles like the [tactical tree stomper](https://www.youtube.com/watch?v=s7yw4qzRdl4) for the ultimate low-ground-pressure. **Low Gravity Considerations** Low gravity is much easier than high gravity. You aren't worried about your materials breaking and ground crumbling, instead you're worried about remaining in contact with the ground. 0.7g isn't much difference, so you'd see many similar vehicles as you do today. That said there are some considerations: 1. Staying on the ground is harder. Here's [the video of the moon buggy driving](https://www.youtube.com/watch?v=EliLP5uEYAU). You can see it bouncing around all over the place. But it's driving, and that's at 0.2g. But your family car will likely require functional aerodynamics (ie spoilers) to push it onto the ground. 2. Similarly, the friction with the ground changes. Friction is dependant on material and normal forces. On a lower gravity world, you have lower normal forces. If a car takes 10m to stop at maximum braking force limited by ground friction, it's take 14.7m to stop on a planet with 0.7g. As a result, I'd expect to see lower speed limites for safety reasons. One thing we can compare with on earth are underwater vehicles. While it doesn't provide 0.7g, you can see some of the issues with [riding bikes underwater here](https://www.youtube.com/watch?time_continue=1&v=G0v7se4XnYs), and [here's a video of an RC truck underwater](https://www.youtube.com/watch?v=wR2UH8J9TGc) ([and another](https://www.youtube.com/watch?v=ImIVR6VawyA)) that looks like it's having issues similar to the moon buggy. I was hoping to find some footage of larger vehicles (perhaps for servicing oil rigs?) but it appears there are no underwater negatively-buoyant driving vehicles (for fairly good reasons). Underwater has a lot more drag than in an atmosphere, so you'd probably see much less tire slip than these vehicles anyway. So, Because 0.7g isn't too low, I'd expect to see vehicles similar to what we have here on earth. Cars, bikes, trucks. You could get bigger payloads with the same engine, but safety would be hard. Some vehicles that are impractical here on Earth may become practical. I'd expect to see more legged vehicles, hovercraft, hydrofoils, small aircraft and so on. **Summary** For much of the time on paved surfaces, normal vehicles would suffice on both worlds. You get 1000kg cars, 2000kg cars, and 500kg cars. You get 10 tonne trucks, 20 tonne trucks, and 5 tonne trucks. All can drive on paved roads here on Earth, and all could probably drive on paved roads on both of the worlds described. Only when you go offroad or want better efficiency do you need custom designs. [Answer] **WORLD A: Yanacocha** **PURPOSE:** The most common vehicle that will be used in this world would be Haulers. As a mining planet, precious ores and minerals needs to be processed and shipped to another planet which will use the processed materials for manufacturing. **REQUIREMENTS:** Due to the hostile environment that the planet has for human life, all types of vehicles must have these requirements when outside the dome city. * Air-sealed, self contained system - Since there is no breathable air in the world, all vehicles must simulate what planes or spaceships have. The vehicles need to be able to provide oxygen, remove C02 and keep the air pressure at levels where a human can live properly. * Structurally solid, and armor - As the inside of the vehicle has a higher pressure than outside, it should be structurally solid to withstand the difference in pressure. Not only that, it needs to be able to withstand the deadly dust storms (assuming that these graphite dust storms are indeed deadly) that happens within the planet. **POWER SOURCE:** Typical combustion engines are out of the question due to the composition of the atmosphere. Batteries can be used to power small vehicles, but for the larger ones like Haulers, a nuclear reactor is recommended. **PROPULSION:** With a hostile environment, wheels can still be used but can cause wear and tear more than usual. Instead, to be able to haul large amounts of ores, as well as lift all the requirements and power source, heavy tracks are the way to go. Large tracks similar to [NASA's crawler transporter](https://en.wikipedia.org/wiki/Crawler-transporter) but wider could be used. It needs to be wider due to the higher gravity, so that it exerts less pressure on the ground. So you can imagine how big the Hauler would be. **World B: Serana** There's not really much of a problem when using any typical vehicles that we have for a lower gravity planet. The lower air pressure maybe a bigger hindrance for helicopters and planes. The atmospheric pressure of World B is similar to Earth at 3500m above sea level. Typical helicopters would be able to fly up at least 1km above sea level with such a low air pressure, instead of 3-4km at Earth. Planes would fly lower, and possibly are more inefficient than what we have on Earth. With a low gravity and air pressure than Earth, it maybe more economical to have rocket-propelled planes instead (SpaceX?). [Answer] The one big factor that changes, is the mass to forces ratio: Your car can only exert forces on the road which are proportional to its weight. ### High-G regime, Yanacocha Your car designers will love this. Your tires can transmit 2.12 times the force as they could on earth. No danger of skidding your tires before you are decelerating with a whopping $20\frac{m}{s^2}$. Your braking distance will half, and you can do turns unimaginable on earth. That said, you need sturdier tires and suspensions than on earth. The forces have to be transmitted, after all. Efficiency will go down, but since when has efficiency been a concern of car manufacturers? There is one more point that needs considerations: Energy dissipation when going down-hill. Twice the weight means that your car's brakes need to absorb twice the amount of energy for the same hight difference. Running brakes hot on long descents is a problem on earth, on Yanacocha this would be much worse. As such, I guess your car designers will invest into electric braking. Either to recuperate the energy for the next ascent, or to dispose it off with a large, specialized radiator under the car's floor: Using electric braking allows you to move the energy disposal anywhere you can place that radiator, and you have no constraints sizing this radiator. ### Low-G regime, Serana What can be said for Yanacocha can be said for Serana in reverse. Braking will be a headache, even though not downhill. Your tires simply won't allow for more than $7\frac{m}{s^2}$ deceleration. Even though any car designed for earth will have no trouble driving, using such cars would be much more dangerous than on earth. Because of this, and the gruesome accidents that happened shortly after the colonization of Serana, individual driving has been restricted to human powered vehicles, only. It's already perfectly possible to kill yourself with a bike, cars are just too dangerous for daily traffic. Instead, Serana has built a big, well developed rail-road system. While acceleration is even worse for rail-roads, trains can easily be controlled by computers which don't do the same mistakes as humans do. This public transportation system allows anyone to get anywhere. ]
[Question] [ ## Background In a far flung land, there exists the country of *Coldesia*. It is large, around the size of the US state of [Alaska](https://en.wikipedia.org/wiki/Alaska). Most of the country is covered with either barren mountain ranges or large forests. The weather is frequently cold (*as the name might imply*) and as a result, the country is often covered in snow, sleet and rain; The temperature rarely reaches above 10 degrees Celsius, with the country seeing temperatures of 5 to -20 from September to May. It has a population of 600,000 - 700,000, with a majority of its citizens living in communes or villages of roughly 100 - 300 people. A majority of these villages are sparsely spaced apart, with human activity not evident for *hundreds* of miles in areas. Most *Coldesians* either live off the land, as farmers/ranchers (not an easy task) or work in the extensive mining industry. Coldesia has been ravaged by war, due to various parties conflicting for control of the state's large supply of minerals and metals. As a result there have been several **purges** which have left the country short of highly skilled workers (teachers, lawyers, doctors, etc.) The current government has a firm grip on the political situation of the country and are well-liked by the populus. They are modernizing and investing in the country's critically underfunded public services, especially in public transport, education and health care, but this massive task will take years, if not decades, to complete due to the expanse of country and due to how sparsely populated it is. Gravel and unpaved roads account for 80% of the road infrastructure. Most people have access to widespread transport through the mainly complete railway system that covers most large Towns and cities. ## Question **How would a country, such as Coldesia (described above), provide a good level of health care throughout the country when there are so few doctors to go round, along with the sparsely populated territory?** NOTE - I did some reading into the [Barefoot doctors](https://en.wikipedia.org/wiki/Barefoot_doctor) that China had during the 1930s-80s. Would a scheme like this be possible? ## Additional Context This world is set in the early 1990s, with the same technology level as the real world at that time. To answer @DJClayworth comment about Flying doctors being a good option, additional sub-question - would this be possible in due to the fact that there is high wind speeds and icy conditions frequently? [Answer] There are a number of variables that need to be taken into account. * Immediacy: People are breaking bones and catching colds kinda all the time. * Education curve: Combat medics can be trained comparatively quickly, but they require support. Full surgeons require a minimum of 4-10 years depending on whether or not you want to risk throwing out the benefits of residency. * Transport costs: It's cold, it's north, and blizzards are not conducive to transportation. * Equipment: And your average village of 300 can't support the cost of an MRI anyway. So... **Step #1: Demographics rule the first day** You have a limited resource. Your country can't survive with lots of happy 300-person villages. Its your industrialized centers with government and education (which are usually the largest populations during the 90s) that are first. You don't tell us exactly, but let's assume [one doctor per 1,000 people](http://www.nationmaster.com/country-info/stats/Health/Physicians/Per-1%2C000-people). That's 700 doctors for the nation. You must protect your national assets, so 2.5 doctors per 1,000 people in the higher density populations, spread the rest around. At a guess, one doctor for every 6-8 villages. This is most sensitive to transport, especially where inclement weather is concerned, but we're talking bush doctors here (planes, cars, trucks). Note that by the 90s the majority of your nation will have a reasonable transport infrastructure — it's really an issue of how much of it was destroyed by war and how much of your repair and maintenance infrastructure went with it. So your real problem is helping people who can't wait 2-4 weeks to see the doctor, or (worse) can't be helped without equipment located at a central location. This is a 60% solution. You'll have people die due to lack of sufficient medical care, but that's what will happen. **Step #2: Triage Education** Each village is expected to send 1-2 people for immediate basic-care training. These folks don't learn about medicine per-se other than first-aid (bone setting, wound cleaning and stitching, very basic illness care). Their predominent purpose is to oversee welfare: clean drinking water, good sanitation habits, etc. Stuff of a preventative nature. This is 6-12 months of training to relieve the stress on the bush doctors. **Step #3: Medics/Physician Assistants/Certified Nurses Assistants ASAP** Thankfully, the proverbial 80%1 of doctoring is made up of cuts, bruises, broken bones, and "basic" illnesses. Panicked 1st-time parents are frequent customers. The vast majority of this kind of doctoring can be dealt with using what in emergencies would be much-simpler-to-train combat medics, PAs, and CNAs. This would minimize the need for doctors to visit the remote areas all the time, leaving them free to focus on the more critical issues that demand their education and experience. These folks would most likely be drawn from your population centers and farmed out to the remote villages on a "we'll pay you a bonus for your sacrifice" plan. Expect (mandate) that each village supplies 4 people for immediate and intensive training. One general practitioner, one PA, one RN, one CNA. What would normally be 4 years of medical school, 3 years of residency, and 2 years of specialization is now 2-3 years of school and 0.5-1 year of residency. Yes, that kind of cramming comes with a price, but it bumps you from 80% of the solution to 90% of the solution.2 So, within 3-4 years of the "epoch" you have most of your doctoring back in place. **Step 4: Equipment & logistics...** Now that you have the people in place, you need pharmaceutical distribution, hospitals, places that need equipment, warehousing, and other logistics. You can draw the people you need from the locations of the (probably) regional healthcare centers. This will include pilots, administrators, everything down to janitors and security. This is the bulk of your redevelopment. Even assuming some of this infrastructure was still in place, it will have needed repair and renovation. At best, 8-15 years. **IMPORTANT** I've made some outrageous assumptions, not the least of which is that a war that knocked off so many skilled surgeons didn't also destroy the truck drivers, warehouse workers, office labor, pharmaceutical manufacturing, and everything else that a very complex 1990s medical industry needs to operate. It's not just the handful of people at the tip of the iceberg (doctors) that you'll need, it's the 50-100 people (minimum) each needed to support them. I'm basically ignoring this other than Step 4. If you must rebuild the entire medical industry from a minimum condition, you're "national healthcare" will be set back to the 1880s. What few doctors exist may know a lot about what to do, but they won't have access to equipment, supplies, and medicine. --- 1 *You know, 80% of the work takes 20% of the time.... I'm using the same kind of generalization.* 2 *You know, 20% of the work takes 80% of the time.... I'm using the same kind of generalization.* [Answer] I'm going to go with the earlier suggestion and suggest you **take a very good look at flying doctors.** You might want to look at how this is dealt with in remote locations in our world, such as Alaska, the Australian outback, and similar locations. You do ask about "high winds and icy conditions". **Ice** is definitely managable by aircraft, if known and planned for. Onboard deicing and anti-icing systems, *properly dimensioned*, can deal with a lot. External deicing, such as that provides on airports by deicing trucks, can also help. (Do note the difference, here; *deicing* removes ice which has formed, while *anti-icing* prevents ice from forming. You'll want both in an aircraft intended for flying in icy or icing conditions.) Ice on the ground isn't that much of a problem; heck, airplanes regularly go to Antarctica and back. Skis on the plane is one way to deal with it; using helicopters and simply taking off and landing nearly vertically (with negligible horizontal velocity) is another. You could also keep a snow plow handy near each field and simply call in with a request for the runway being cleared of snow before you land. Each way of dealing with it has its own advantages and drawbacks, but it's not an insurmountable problem by a long shot. Plain **wind** isn't a huge problem, at least as long as it isn't causing major turbulence near the ground. What's a problem for an airplane is *crosswind*. The crosswind component is the equivalent wind were the wind to blow at the aircraft straight from the side. This can be mitigated by simply clearing out more than one runway at each location, thus allowing the pilot to choose the one offering the most favorable wind conditions at the time. Runways don't need to be hard-surfaced; [soft field operations is a very real thing](https://www.aopa.org/news-and-media/all-news/2017/november/flight-training-magazine/technique-soft-field-landing), especially in general aviation. So is, also, what's known as "short field" operations, where the focus is on getting off the ground and getting some obstacle clearance in as little ground distance as possible (and correspondingly, getting down and stopping in as little ground distance as possible). Demonstrating proficiency with short field and soft field techniques is a requirement to get a pilot's license in our world. A small aircraft, especially if equipped with a powerful engine, doesn't need much ground distance to get airborne. To get an idea of the speeds involved, the rotation speed (when the pilot starts lifting the aircraft off the ground) of something like a Cessna 172 is around 55 knots or 100 km/h. The only major **societal** concern I'd have with this is probably the fact that "there have been several purges which have left the country short of highly skilled workers (teachers, lawyers, doctors, etc.)". For this to work, you are going to need both doctors and pilots; ideally doctors who are also pilots, but pairing them up for the trip can work, too. Your government is going to want to somehow encourage people to learn such trades. As [JBH mentioned](https://worldbuilding.stackexchange.com/a/124681/29), early triage is going to be critical to manage the scarce resource, and first aid is going to be critical because even if they're literally sitting at the airport ready to go, it's going to take a while for your doctors to arrive. (Estimate 150-250 km/h *airspeed* for small aircraft. Subtract whatever the headwind component they're fighting against is, or add the tailwind component, and you can easily look at a ground speed of anywhere in the 100-300 km/h range.) [Answer] I live in Nunavut, which has an area larger than Alaska, a population of 40,000 people, and a climate significantly worse than what you propose; -20 C during the period of September to May? That's *balmy* where I live. A temperature of -20 C for winter months can be the record high for some communities. So, some actual data. First, your population is going to be mroe urbanized than you think, with not many people living in small villages of 100-300 people. Both Alaska and Nunavut demonstrate this. Of the 40,000 people in Nunavut, nearly 1/5th live in Iqaluit, capital and largest (and only) city. There tends to be a flow from the smallest communities to the larger ones, so the small ones keep getting smaller and the larger ones bigger. Alaska has 740,000 people, and Anchorage and the intermediate surrounding communities have over half of them (402,000), then Fairbanks and Juneau with about 31,000 each. Larger communities will be the ones offering greater services, which will attract more people, which will increase demand for services, which will draw more business and spending, which will attract more people, and so on. The government will set up regional centers from which their services are provided to surrounding, smaller, communities, and people and private services will likewise gravitate toward those centers (or communities in close proximity). In terms of medical service, what you're likely to see, based on the system I work with here: * Hospitals and major treatment centers will be located in the largest cities and regional centres. Your specialists will be in the major cities. * Smaller communities will have clinics. They will be staffed (not counting support staff) primarily by nurses and nurse practitioners. Doctors and some specialists will probably do rounds among several clinics within their operating area. * Patients who need long term care or more intense treatment will likely be flown to the major centers. The government may put up special facilities (those for psychiatric treatment, elders' care, and such) in communities outside the main ones, but they will serve people from multiple communities. * Major emergency situation will be handled by aircraft medevac, with dedicated aircraft and medical flight teams to transport patients. What counts as an emergency requiring aircraft will vary: assuming no additional significant injuries, something like a broken arm, as long as properly set and in a cast, can be handled locally. On the other hand, a possible cardiac event will likely require medevac. The aircraft will be based in centralized locations, so there isn't a plane waiting in every community all the time. This means it's possible for hours to elapse, or worse due to weather conditions, before someone may get treatment they require. * When possible, patients will be flown under medical contracts on regular airline flights (we call them "schedevacs"). [Answer] Given that level of technology [Flying Doctors](https://en.wikipedia.org/wiki/Royal_Flying_Doctor_Service_of_Australia) are definitely an option, since they were flying planes in Antarctica earlier than that, and the alpine rescue choppers in the Himalayas date from as early as the 1970s. ]
[Question] [ In my world, an engine very similar to the [SABRE engine](https://en.wikipedia.org/wiki/SABRE_(rocket_engine)) has been made. Along with it is the development of [WEAV propulsion systems](https://www.scientificamerican.com/article/worlds-first-flying-saucer/). The SABRE engine is a hybrid between a hypersonic jet engine and a rocket engine. It uses the jet configuration to get to high atmosphere, and then uses the rocket configuration to propel it into space. It has a speed of mach 5.4 in jet mode, and mach 25 in rocket mode. WEAV propulsion systems are systems using electrolodes on the hull of the craft to vaporize the surrounding air into plasma and then using a magnetic field to manipulate the plasma so that it pushes air away from the craft generating lift and thrust with no moving parts. What I'm envisioning is a craft that takes off VTOL style with the WEAV. Uses the jet to reach high altitude, and then blasts into space with the rocket. Assuming all other design features of the aircraft were accounted for, how would this affect air to air combat if it was mounted onto a future air superiority fighter similar in function to the F-22 or bomber similar in function to the B-2 spirit, but designed to accept these features? [Answer] This sort of engine would not be at all useful on a fighter, but would make a really nifty bomber. A fighter needs agility more than anything, and flying at Mach 10 or 20 gives you just the opposite. A really, really fast fighter would be nearly invulnerable (like the SR-71 it could just fly away from air-to-air or ground-to-air missiles), but its turning radius would be many counties wide and its ability to dogfight nil. (Unless it slowed down enough that it's fancy engine was grossly inefficient. So still nil.) OTOH, as a bomber, it could fly just about any trajectory you wanted -- in air, in space, straight lines, curved lines, whatever -- and get to anywhere on Earth in about 45 minutes while under perfect command control. There's no known defense against something flying so fast and so high. (There are rumors of an Aurora bomber produced in prototype in the 80s that could do Mach 5. The rumors are probably false, but were *plausible* enough to be reported in trade journals like *Aviation Week*. Speed is a bomber's friend.) [Answer] Assuming that it works as you envision (see the answer by Renan), you'd get the ability to go to low earth orbit from anywhere in the world. * ASAT missions against low-orbit sats become easier. But we already had that with the [ASM-135](https://en.wikipedia.org/wiki/ASM-135_ASAT). * It might become feasible to do defensive space patrols to defend orbital infrastructure to counter ASATs. * Instead of launching a recon sat on a predictable orbit, the role could be filled by (manned or unmanned) shuttles. On top of that, *commercial* use of space would skyrocket (pun intended). That means more infrastructure in low orbit, more industry, more activity to hide military assets. With more activity in LEO, there would be fueling and transfer stations to go to GEO. Orbital fighters and battleships? From that it might become feasible to go to the asteroids, bring back metals and other materials for use in orbit. The sky is your limit. [Answer] The primary advantage of such a craft is getting from point A to point B very quickly indeed (orbital velocity is Mach 25), but as many people have pointed out the vehicle moving at that velocity is essentially travelling in a straight line. You can manoeuvre, but it will be both costly in energy, time and space. So the actual function of the vehicle will be as a carrier platform. A target is identified, and the the vehicle is dispatched. Over the target area (or in international airspace, depending on the scenario), [UAV's](https://infogalactic.com/info/Unmanned_aerial_vehicle) and [UCAVs](https://infogalactic.com/info/Unmanned_combat_aerial_vehicle) are dispensed, which slow down to operational speeds and then carry out the mission. Alternatively, projectiles resembling darts are released and coast to the targets at @25 times the speed of sound. To put that in a bit of perspective, the jet of molten metal projected by a HEAT charge is also moving at Mach 25, and that few ounces of metal can penetrate heavy armour and destroy a tank or bunker. While no hypersonic dispensing of weapons or vehicles has been demonstrated yet, it is an extension of dispensing UAV's at high speeds, as [demonstrated by F-18 fighters](https://www.popularmechanics.com/military/aviation/a24675/pentagon-autonomous-swarming-drones/). Without doing too much handwaving, it can be assumed the weapons and UAV's are designed to withstand the ejection at speed, and rapidly orient themselves to the target once clear of the plasma sheath of the carrier vehicle. [![enter image description here](https://i.stack.imgur.com/4shdM.jpg)](https://i.stack.imgur.com/4shdM.jpg) *Perdix deployment from an F-18* The plasma sheath represents both a cost (the vehicle will be highly visible once in the atmosphere) and an opportunity (the sheath is proof against both radio waves and lasers, providing defence against hacking and a whole class of directed energy weapons). The final issue is what form factor would work best for such a vehicle? I would suggest a "[wave rider](https://infogalactic.com/info/WaveRider)", which "surfs" on its own supersonic shockwave, providing a much more efficient use of energy, and can carry the dispensed weapons or UAV's on the top surface, which is largely clear of the effects of hypersonic flight (the shockwaves are trapped beneath the vehicle) [![enter image description here](https://i.stack.imgur.com/VjeRB.jpg)](https://i.stack.imgur.com/VjeRB.jpg) *Possible design for a Mach 25 Waverider* So an SSTO craft would serve most effectively as a carrier and dispenser of the actual combat vehicles into the target area. [Answer] What you envision is fighter jets that would be able to travel in space. There is a huge problem with that. One thing that rockets need is an oxidizer. SABRE is awesome in that, while within the atmosphere, it can use the freely available O2 for that (hence its "air-breathing" aspect). It can switch to onboard stored oxidizer when needed (i.e.: too high in the atmosphere, or in space). While in space, though, your fighter needs to bring its own oxidizer, which adds weight to the craft. It also needs A LOT of oxidizer in order to maneuver. That will make them much larger and heavier. [The Lockheed Martin F-22A](https://en.wikipedia.org/wiki/Lockheed_Martin_F-22_Raptor#Specifications_(F-22A)) when loaded, can weight up to approximately 29.5 tons. Of that, nearly 10 tons are going to be in payload. It is designed for speed and combat. Now compare with the [Space Shuttle](https://en.wikipedia.org/wiki/Space_Shuttle#Specifications), which weights 78 tons when empty, and can take a payload of 27 tons to a low earth orbit. But in order to to that, it needs the help of **a 756 tons external tank**, and **two solid-fuel rocket boosters which weight 571 tons each**. Supposing you'd wish your fighters to have the same autonomy in space as the space shuttle, they would need a launch setup similar to that of the Shuttle, albeit smaller and lighter. But the launch would still involve boosters and probably external tanks with weights ranging in the hundreds of tons. The alternative is not giving the fighters any oxidizer at all, or no more than a handful tons... They could do short incursions into the upper atmosphere on suborbital paths, like the [North American X-15](https://en.wikipedia.org/wiki/North_American_X-15) did in the 60's. This does not seem very useful in warfare, otherwise this design would be commonplace. Compare with F-15, F-22 and F-117, none of which is designed for space flight. ]
[Question] [ I am creating a species for my alien world that will be seen as 'holy' by the planets dominant religion. I'd like to know if my 'holy' species could viably exist biologically/evolutionarily. Assume that the alien planet has the same general physical properties as ours, the only difference being a higher oxygen content and slightly less gravity. The species is a marsupial, slightly larger in size than a above average capybara. It is a herbivore and has raccoon like hands with opposable thumbs. Here is the part where it becomes alien: the females of the species have large downward curving horns on either side of its head, like a ram, but flatter and concave. They use these to scoop up soil and plant life and then grow them in the horns. This is like an emergency supply of food for their young encase there is none around them. Specifically the type of soil/plant they scrape up into their horns would be ground racing berry plants like strawberries. These berries would actually ripen and grow quicker in their horns because of a hormone that the species produces called ethylene which promotes the ripening of fruit. This is the reason the dominant religion on the planet thinks they are holy as they use 'magic' although it isn't really. The male of the species also have horns but do not produce the hormone and their horns are frontward facing and used for fighting/mating purposes. So is this a realistic species that could have evolved? Some points I'm worried about being unrealistic: * A mammal producing a hormone like ethylene. * A species' male and female having very different horns. * The viability of the plants being able to grow after being uprooted. (Perhaps they would need to just be soil with the seeds in it but not grown yet?) [Answer] I like it. There is no reason a berry plant could not grow in a small pot. So there is no reason it could not grow in a horn. The soil would leach nitrogen from the horn; keratin (usually hair, but why not horn)is good mulch for this reason. Sexual dimorphism: if horn is for a purpose unrelated to gender females and males can both have horns. Male and female cape buffalo have similar horns because they are for fighting predators, not conspecifics. So your berry pot horns can be on males and females both. My one change: the berry is not for food. You could not grow enough calories in a horn to make a difference for an animal big enough to carry around the horn. **The berry makes vitamins.** I could carry around a pot big enough to grow enough scurvygrass to prevent myself from getting vitamin C deficient. So too your creatures: their diet and environment is low in a given vitamin they need but the berry makes that in abundance. The berries carried by the animals make much more vitamin than the wild version does. Animals with high vitamin berries do better and have stronger offspring. Those offspring get runners of the berries of their parents. Over time mutual selection favors super berries. [Answer] There is a major problem with this species: a plant needs nutrients to grow. Not just sunshine and CO2, but water, minerals, proteins etc. Normally, those would be acquired from the soil and/or from symbiont microorganisms. If, instead, those nutrients come from the carrying animal, then the carrying animal is expending precious energy and resources now, for a "just-in-case" later scenario. There are also a number of smaller problems. * Plants require sunlight. Is your animal diurnal? Even if it is, does it favour open spaces (as opposed to being under trees)? Does it have no need to hide from predators? * Having plants to the side of the animal's face would significantly constrict it's field of view, making it considerably harder for it to hunt/scavenge for food, avoid predators etc. It would be like a horse wearing blinkers. * The extra weight of the plant would add to the energy the animal must expend to sustain it. Also, it would shift the animal's centre of mass, potentially off-balancing it. * For a plant to produce fruit, it needs a considerable amount of water and nutrients, A starving plant will not produce fruit. So, in a period of starvation, your animal would be sustaining a plant, giving it more energy than it would receive back from the fruit. A plant-animal symbiosis is possible, but the animal needs to benefit from it all the time, not only in edge cases. Otherwise, the costs outweigh the benefits. [Answer] I would go with: Grow - no Ripen - yes Indeed, the ripening could be an example of mutualistic evolution - the plant gains something from the animals' carrying of the fruit (perhaps the fruit sheds seeds gradually as the animal walks around) whilst the animal gets the fruit to ripen and make it much more palatable to eat. But it's hard to imagine fruit growing much - although it is theoretically possible; the fruit could photosynthesise and draw chemicals from the atmosphere. ]
[Question] [ The original dream of the alchemists was to turn base metals into gold, however it's quite obvious that after that becomes cheap and easy it becomes basically useless since much of gold's value comes from its rarity. But suppose the alchemists had achieved the ability to convert between different metals (ignoring that this is basically impossible IRL) what applications would this be used for in the real (modern) world? The obvious ones that jump out at me are turning a ton of lead into plutonium or producing things like the chromium or the rare earths cheaply but I'm sure there are plenty I haven't thought off. What sort of applications would there be for alchemy like this? Or for the dramatically increased availability of currently expensive materials like REE, silver etc... [Answer] Well, first of all, if you're going to turn a ton of lead into plutonium, I hope you do it in *very* small batches! Besides the idea you've already come up with -- making rare elements -- there's also the possibility of *unmaking* elements: Use alchemy to make reactor fuel out of common materials, and then use it again to make common materials out of the radioactive waste. You'd have a real closed cycle. [Answer] Keeping it limited to metals you have a lot of options. You can create unlimited energy by transmuting metals from an oxidized state to a non-oxidized state. This is assuming that oxidized metals still count as metal. In principle you create an unlimited battery by breaking one part of the redox cycle. Another useful application of transmutation is that you could pick the best state for your metal during production and once done transmute it. So you could construct buildings with aluminum, nice light weight and easily malleable. Once your building or floor is done transmute all the aluminum to steel making it strong. Note that there is carbon in steel so I am not sure if this is allowed. Also during processing you could do very interesting things. Chips and printed circut boards (PCBs) are made of very thin layers of metal, copper and silicon. Using gold instead of copper is very nice for PCBs, so here your transmutation to gold comes in if you want. Now it's mainly used for high end application (smart phones, etc.) due to the price. But even more interesting is creating the thin layers. It would be possible to use mercury to create very thin layers or even tracks and then transmute them to gold or copper. Basically all your metals can be used as a liquid. You could do very cheap injection molding with metals, like now is done with most plastics. Also depending on what you would classify as a metal you can create everything from sand. Silicon is a metalloid and sand is mostly silicon oxide, so no more mining of anything, just use sand for everything. You could build a sandcastle and make a solid steel house of it. As a minor side note you would also have saved the universe from an energy death. ]
[Question] [ ***Summary:*** Questioner wants to know the best way to restrain a person in order to prevent self-harm, while minimizing discomfort, facilitating their cleanliness and ongoing education, allowing entertainment and providing opportunities for copulation while protecting their partner from unexpected violent mood shifts, all the while maintaining a discreet watch by stenographers recording the person's speech. Tech level is Victorian England. **Backstory:** Several hundred years ago, certain youths in foreign lands began to be - for want of a less superstitious term - possessed by spirits of prophecy. Such persons so afflicted have mental states that vary between lucidity, drooling imbecility, and most significantly, prescience or violence and self-destructiveness, and the shifts in mental state are swift and unpredictable. Since these prophets have been shown to have demonstrably accurate and specific powers of prophecy, they are a valuable resource of national importance. However, in all but a very few cases, their self-destructiveness and suicidal tendencies leads to a very short useful lifespan as a prophet unless placed in restraints that prevent self-harm. Unfortunately, restraints strict enough to prevent self-harm can themselves be harmful. In the nations in which prophets first appeared, prophets were variously chained permanently spread-eagled upon crude stone slabs, lying in their own filth in hollows worn into the stone by generations of prophets who had lived out the remainder of their lives there before them, or pinioned within casks with only their hands, head and posterior protruding, amongst other yet more barbaric means of restraint. So, enough of the historical background. Prophets were formerly found only in less civilised realms, where individual lives were of little importance when placed beside the needs of the state. However, a fortunate accident of inheritance has led to the occurrence of prophets in our own nation. It has been demonstrated by our scientists that the children of a prophet have an approximately 1 in 2 chance of being prophets themselves, but while around 2 in 3 children born of two prophets will also be prophets, there is a 1 in 4 chance that the infant will be stillborn, and should that be the case, the mother is also unlikely to survive the pregnancy. Given that such a mother would herself be a prophet, once the risks were recognized, prophets were forbidden to be bred to other prophets. That being the case, women of our region - either those who could pass as natives of the nations in which prophets were present, or true natives who had been convinced to change their allegiance - volunteered to couple with male prophets in the hope of being impregnated with a child who would become a prophet, and would be born in our own region. Such women must have had strong stomachs, given the squalor in which prophets were kept, and their poor state of health and grooming, not to mention that they were actively trying to bear a child who would be cursed to a lifetime of slavery and degradation. Now that we have our own prophets, our scientists have made further discoveries, with the assistance of a small handful of prophets who were able to control their self-destructive and suicidal urges while conscious. While a prophet need not even be normally capable of speech in order to prophesise, educated prophets give better prophecies, as the prophecy appears to be filtered through the prophet's mind to a degree. Additionally, healthy, happy prophets live longer and are of more use than mistreated slaves bound perpetually in their own filth until their untimely demise from festering pressure sores or other diseases. To this end, our monarch has commissioned a study into the best way to restrain a prophet in order to prevent self-harm, while minimizing discomfort, facilitating their cleanliness and ongoing education, allowing entertainment and providing opportunities for copulation while protecting their partner from unexpected violent mood shifts, all the while maintaining a discreet watch by stenographers who are tasked to record any prophetic utterances. As it has been shown over centuries that contact with a wide variety of people stimulates prophesy, our prophets' living conditions must be such that they are accessible to the general public, able to make physical, even intimate, contact with them, yet protected from assassins. To this end, I am seeking public submissions as to the best way to maintain prophets in safety and comfort for all, maximising their useful lifespans and minimising the impact of their inevitable servitude, while ensuring that no prophesy goes unrecorded. Please consider that our nation has technological capabilities similar to that of Victorian England, though our mores are rather less restrictive and class-based for the most part. Save for prophesy, magic is mere superstition or trickery. **Edit** Using individuals trained in the martial arts to restrain otherwise unrestrained prophets has met with only limited success. Prophets in a psychotic state have been known to exhibit hysterical strength and have a complete disregard for pain, and have been known to dislocate their own joints in order to escape a hold. Combined with the instant shifts in mental state, a prophet can do significant damage to themselves or others before their handlers can react. The use of drugs has likewise been found to be of limited value. A prophet can slip instantly into a prophetic state at any time, even when in the midst of a violent outburst or an act of copulation, and the mental impairment that such drugs cause degrades the value of the prophecy. Additionally, some, but not all, violent outbursts appear to be uncontrollable by means of drugs, and are said by the superstitious to be the work of the possessing spirit, as prophets in such states have been observed employing martial skills that they have never learned and sometimes ought not be capable of performing at all, and seem immune to most drugs at such times. Some few prophets appear to have an innate untrained ability to suppress their violent and self-destructive outbursts while conscious, though they exhibit visible signs of considerable mental and physical stress while doing so, and are not capable of suppressing an outburst that occurs during sleep or sedation. A few more prophets have been successfully trained to be similarly able to suppress their violent and self-destructive outbursts, but the majority do not appear capable of benefiting from such training. Many prophets show signs of depression, and it is thought that the unresponsive state that many show is more a result of that depression than an effect related to the ability to prophesise. In good conditions, prophets show fewer and shorter bouts of unresponsiveness. Providing prophets with sexual partners is considered to be a good practise on multiple levels. As the prophetic curse almost invariably appears to strike during late puberty, new prophets are typically teenagers with the usual sexual urges. Providing them with sexual partners has been shown to reduce their stress levels and the frequency of undesirable mental states, and additionally provides the chance of new prophets to be born. Providing many sexual partners has been shown to broaden the range of their prophesies, and a new sexual partner is likely to trigger a shift to a prophetic state. However, violent outbursts directed at their sexual partners is also fairly common. Given the necessity for intimate contact at such times, it is unlikely that a handler could prevent injury to the partner through martial techniques alone. [Answer] We recommend a layered approach to securing these individuals. These protective layers will be based on the following observed behaviors and requirements to date: **Behaviors** 1. Random and extreme mood swings 2. A mood in which violence to the self or others is likely and intentional 3. [Inordinate strength](https://worldbuilding.stackexchange.com/questions/103134/proper-care-and-feeding-of-prophets-or-how-to-keep-a-human-in-strict-restraints/103168#comment310345_103137) when victim to a violent phase **Requirements** 1. Some freedom of motion 2. Safe access to others for educational, social, or intimate purposes 3. Ability to present prophesies **Assumptions** We assume these individuals are not trainable to reduce the length or severity of violent episodes. If this were the case, we would advise methods that [have been researched](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1311295/pdf/jaba00109-0025.pdf) in controlling the self-harm of mentally deficient individuals, such as applying lemon juice to the mouth during a non-desired behavior. We also note that such activity would likely be hazardous to the health of others, and may not be recommended, dependent on the severity of the violent episode. With these factors in mind, we present the following solution. **Primary Protection - Restraint** The prophetic individual should be secured at all times using a [belly chain](https://en.wikipedia.org/wiki/Belly_chain_(restraint)). This device allows the subject limited motion to eat, point, write, etc. while "restricting arm motion to prevent the [subject] from butting or hitting." In accordance with the inordinate strength noted in the past, we advise heavier chain than would be utilized for high-risk inmates placed in similar restraints. During sessions with others, ankle bindings may also be employed and it is advised the chains be secured to a solid surface, such as a heavy chair or the frame of a bed; the latter is especially advised for intimate sessions. **Secondary Protection - Personnel and Technology** There should always be at least two attendants available to facilitate or restrain the prophetic individual, both being individuals of strength to handle the observed inordinate strength of the subject's manic episodes. These individuals should be trained to notice mood swings, either impending or happening, and be alert and ready to respond. Additionally, we advise using a cutting edge device that has seen particular acclaim from ranchers: a [cattle prod](https://en.wikipedia.org/wiki/Cattle_prod). The electric charge from the device will assist the attendant personnel to direct or interfere with the activities of the subject. **Tertiary Protection - Environment** A [padded cell](https://en.wikipedia.org/wiki/Padded_cell) should be provided the prophetic individual. This room will feature no furnishings or windows and have a single entry point. During extreme bouts of mania, the attendants should place the subject in this room for safety, until the mania passes. Additionally, the subject should have access to a grassy enclosure, for psychological reasons, and eating, education, public, entertainment, and relaxation areas, to provide basic needs and offer mental and physical stimulation. In all environments, the attendants must have free and easy access to the subject. Environments in which the subject interacts with the public must be secured prior to the subject's entry to the area. In such areas, we advise a fence, either chain link or bars, to limit the subject's access to the public. **Emergency Protection - Anesthesia** Finally, in an emergency case, and thankfully for [medical advances](http://www.victorian-era.org/victorian-era-discoveries-inventions.html), we advise the use of an anesthetic grenade, a device capable of deploying a sleep-inducing gas, for instances where the prophetic individual escapes restraint during a manic episode and cannot be restrained through force from the attendants. We have [previously recommended](https://worldbuilding.stackexchange.com/a/75069/6986) such a device with notable success. [Answer] Your best bet would be to keep the prophet surrounded by guards at all times. They should be adept at at least one, if not multiple, forms of non lethal combat. From personal experience, I can say that many moves used in Japanese and oriental martial arts, like judo and ju-jitsu, can be difficult to escape from. The guards should be able to coordinate well with each other, for an easier restraint and all be familiar with the others techniques. If we're talking the late Victorian era, then we can employ the use of sedatives. By this time there's the hypodermic needle and morphine as well as some types of opiate salts. If you keep someone well trained in medicine with the prophet, then they could very quickly either inject him with morphine, or a similar sedative; or if you prefer, the needle could already be in the prophet, and the doctor need only depress it to inject the sedative. From what you've described, it would be extremely difficult to sedate the prophet using opiate salts taken in through the respiratory system, however that is another sedation method. As you say, the prophets can get extremely violent, so it would also be advisable for your doctor to also be trained in combat to some extent. The sedation will only be temporary though and will mostly just buy time to restrain the prophet if they're as strong as you say. The prophet's hands will most likely be their most damaging body parts as they allow for the most dexterity. To restrain the hands individually, you could have some form of glove that they wear at all times and has a sort of string system inside whereby, a guard would simply need to pull a cord on the glove's exterior and it would seize up on the hand. A simple pair of handcuffs can then hold the hands together and out of the way. To bring more control of the arms quickly, a similar device to handcuffs can be used, but around the upper arm. Imagine a strong strap around each upper arm connected together by a series of strong rope, or string or something, that can be left loose in most situations, and allow for regular mobility but again, like the gloves, a pull of a cord binds the two arms behind the prophet's back. You can restrain the rest of their limbs in the same sort of way: two straps on the limbs, connected bus string or rope, and can be pulled together to restrain the prophet at the pull of a cord. If you set all of these up properly, the you should be able to quickly force the prophet into some form of restraint, either flat or in a ball. Once there the main concern is keeping the prophet safe. Some form of brace, like a neck-brace, may be applied to any limbs needed to ensure that the prophet stays restrained and can't damage a limb by thrashing around. [Answer] The best protective restraints are the arms of skilled caregivers trained in [Aikido](https://en.wikipedia.org/wiki/Aikido) and [Greco-Roman Westling](https://en.wikipedia.org/wiki/Greco-Roman_wrestling). These professionals serve to defend their assigned prophet from both assasination and self-damage. Whenever a suicidal action is attempted, the guardians neutralize the threat using pressure points, flips, pins and holds. When necessary, the guardians can hold the prophet safely motionless until a more manageable mental state returns. Three teams of three master-level athletes are assigned to each prophet, with each team covering an eight hour shift. The prophet is never left with less than two alert and ready guardians watching his every move. The third guardian is present for the unlikely event of a simultaneous assassination and suicide attempt. This guardian also performs all potentially dangerous services (such as shaving and cutting meat) while the other two hold the prophet motionless. Although a variety of padded bondage devices are kept nearby to help with more lengthy bouts of dangerous behavior, their use is discouraged from day to day use. The prophet must remain free to interact with the populace whenever they are sane enough to do so safely. Assisted by this defensive staff, and similar teams of stenographers, doctors and teachers, current day prophets live a much more luxurious life than their enslaved forebears. And the resulting improvement in prophecy quantity and quality, more than makes up for the additional expense to the kingdom. [Answer] > > While a prophet need not even be normally capable of speech in order to prophesise, educated prophets give better prophecies, as the prophecy appears to be filtered through the prophet's mind to a degree. > > > If the prophet's mind tunes the prophecy, can you get a prophet focused on the well-being of the other prophets? If you had one prophet that could predict when the others will attempt self-harm, you could be far more relaxed with all the other prophets and just keep the one protected, relying on the one to notify you in advance of problems with the others. [Answer] 1. Keep them fixed in place, on a padded chair with reclining capabilities. 2. Keep the restraints heavy and tight so no movement outside of chewing, talking, drinking, and minor fidgeting is possible. 3. Place tubes for the removal of excrement and urine, as well as menstrual fluid for female prophets. 4. They should be able to be positioned so as to allow for intercourse. 5. They should be gaurded at all times, and moved every two hours, with limbs massaged. There is always the possibility of using the less pleasant suggestion of our friend Phoenix. ]
[Question] [ The setup; We have discovered the ability to make super-men... well not quite, but we can do super-er men. They are...actually not that super, basically just bigger and a little more monstrous. And hey, we have some nasty mean alien things invading the planet from some strange dimension, a perfect reason to *make* these larger than average people and turn them into soldiers! Simple question: How big would someone have to be, size and weight wise, to be able to shoulder a ma-deuce ([M2 Browning](https://en.wikipedia.org/wiki/M2_Browning)) and fire it singly and in full auto (akin to how someone can shoulder and fire an AR-15 or AK-47) with acceptable control and accuracy by military standards? Assume that the weapon is fitted with an appropriate stock, grip, trigger, and hand-holds. For reference: <https://www.youtube.com/watch?v=U1mG9Yf9yQ0> A video where someone actually slings and fires a m2, but his ability to control it while firing is...sub par. I believe he stops trying to fire it full-auto because of his lack of control. [Answer] The M2, a hundred-year-old design, is massively heavy (84lbs) for the caliber it fires. Modern weapons in the same caliber, such as the M82 anti-materiel rifle or XM806 machine gun, are substantially lighter. However, I ran the numbers, and found that the M2's ratio of recoil momentum to weapon weight is actually comparable to modern assault rifles. Thus, there are two ways to approach this question. **1. Running the numbers on the M2** The .50 BMG has approximately 11 times the momentum (and consequently recoil impulse) of the 5.56x45mm NATO cartridge, a common intermediate-caliber rifle round. Dividing the M2's 84lb weight (I'm assuming the additional weight of fitting rifle furniture and controls will be offset by lightening modifications) by 11 yields 7.6lbs, meaning that a 7.6lb 5.56 rifle has the same basic recoil profile as the M2. 7.6lbs is actually a typical weight of an accessory-equipped M16A4 rifle, a weapon platform which is typically considered fairly controllable in fully-automatic fire. It's not nearly as effective in this role as a machine gun, and it's virtually always employed in semi-automatic to maximize effectiveness, but when used on full-auto it is much less spray-and-pray than, say, an AK. The M2's lower rate of fire, about 2/3 that of the M16, will make it more controllable, so this seems like a good analogue for the handling characteristics stated in the question. So, assuming a linear extrapolation of mass to strength and proportional size increase (we're glossing over the issues involved in scaling up humans, right?) a 5'10", 150lb human wielding an M16 is roughly equivalent to a **13'0", 1650lb** human wielding the M2. **2. Running the numbers on a more modern, man-portable .50BMG weapon** The [Barrett M82](https://en.wikipedia.org/wiki/Barrett_M82) is a 30lb rifle intended to be carried and fired by a single person, and is much closer to assault rifle ergonomics than the M2. It is not intended to be fired from the shoulder, but it's still heavy enough that the recoil isn't bad. The M82 isn't normally capable of full-auto, but redesigning it with a full-auto trigger pack wouldn't be too difficult. Using the 7.62x51mm NATO as a comparison, which has about one-fifth the recoil momentum of the .50BMG, the 30lb M82's recoil profile is comparable to a 6lb rifle in 7.62x51- only a little lighter than the AR-10, which was a 7.25lb 7.62x51 rifle intended to be capable of full-auto fire. So, to have equivalent performance, we only need to scale up a human by a factor of 5. A 5'10", 150lb human now scales up to **10'0" and 750lbs**. Note that in this giant's hands, the M82 will behave like a [battle rifle](https://en.wikipedia.org/wiki/Battle_rifle), *not* an [assault rifle](https://en.wikipedia.org/wiki/Assault_rifle). Full-auto fire will, even with a reduced cyclic rate compared to actual battle rifles, will purely be for suppressive fire. For engaging point targets, semi-automatic fire will be much more effective- as is the case with every other shoulder-fired rifle, including the M16 and the big-giant-with-an-M2 described above. If you want to tweak these numbers, or find a middle ground: A smaller giant with the M2 will find it controllable, but heavy and difficult to carry, akin to a light machine gun in human hands. A larger giant with the M82 will find it very light and easy to carry, but 'snappy' in its recoil, and may actually benefit from adding on a drum magazine or conversion to belt-feed to add mass to the weapon platform. [Answer] # You need only a common man, but with uncommon valor You can read John Basilone's [Medal of Honor citation](http://www.victoryinstitute.net/blogs/utb/1942/10/24/john-basilone-medal-of-honor-citation/). What the citation does not say, but what every enlisted Marine knows is the gospel truth, is that John Basilone over-ran an M2 position that had previously been overrun by the Japanese, picked up the M2, cleared its jammed feed, and operated it from the standing position, single handed halting a Japanese bayonet charge. A regular sized person can operate an M2 without a tripod...as long as they have the Heart of a Marine. Oooooohraaaah!!!! [![enter image description here](https://i.stack.imgur.com/L16eD.jpg)](https://i.stack.imgur.com/L16eD.jpg) [Answer] You don't need Steve Rogers, you need Jim Rhodes. Genetically modifying people takes too long to pay off. Investing in mechatronics is cheaper and has way less ethical concerns. It is even a reality today, in our world, by means of the [powered exoskeleton](https://en.m.wikipedia.org/wiki/Powered_exoskeleton). From the linked wiki: > > There are an increasing number of applications for an exoskeleton, such as decreased fatigue and increased productivity whilst unloading supplies or enabling a soldier to carry heavy objects (40–300 kg) while running or climbing stairs. Not only could a soldier potentially carry more weight, presumably, they could wield heavier armor and weapons while lowering their metabolic rate or maintaining the same rate with more carry capacity. Some models use a hydraulic system controlled by an on-board computer. > > > So, not only is this more mass-produceable than people created in vaults, these things also will have the accuracy that comes with electronics, and you have more control over who gets the ability to go Rambo with M2's - just give suits to already trained marines and other soldiers, and turn a suit off if the user goes rogue. DARPA has been putting serious money on it for years now, and it isn't even a secret project. ![Heavy boots of lead fill his victims full of dread](https://i.stack.imgur.com/DzEwd.jpg) Source: <https://www.armytimes.com/news/your-army/2014/11/30/army-testing-load-lightening-exosuits/> [Answer] Maths and physics are against you: strength goes as height squared, whereas mass goes as height cubed. Now an AK has a mass of 3.5 kgs, an M2 around 38 kgs, say a tenfold increase. So your giant grunt has to be ten times as strong, that is $\sqrt{10}$ time as tall (around five meters), and so have a mass around two tons. Not very handy. Another problem: who carries the ammo? M2 cartridges are 117 grams each, and how much do you want to fire ? Semi auto is 40 rounds per minute, that is 4.7 kgs of ammo per minute. Or maybe full auto? That's 450 rounds per minute, around 50 kgs of ammo per minute. You are not going to fire for very long. How are they transported to the fight zone? Helicopter? Fuel costs, you know, and big helicopters are a nice target (Black Hawk in Mogadishu...). Truck? You need a nice road to get there, and roads are easily bombed. The real problem, however is another: a giant man is not very dangerous. Human knees and feet are not designed to carry much weight, and your giant man weighs a lot. A heavy person has more trouble climbing than a light one. So, if you are smart, you could just outrun him. A giant man has his feet more distant from his brain than you do, so he is more likely to trip and fall, and when one of them trips and falls over, his head falls from an higher place, and strikes the soil at higher speed. Giants may be good for fantasy, but for scifi not so much [Answer] A little perspective from a former machine gunner. When I was assigned to the armory for a little while I got the chance to handle a lot of .50 cal machine guns. I used to carry them around fully assembled all the time (most people would pull off the barrel before moving them because they are really heavy). Firing one without any tripod is possible, but even a "super man" probably wouldn't shoulder it. They would fire it like I fired my 7.62mm machine gun: from the hip. I'd hold the bipod with my left hand, wrap my right arm around the butt to hold the grip, and pull a little against the strap with my upper body, holding the machine gun up against me. This created a nice, stable firing position. One major reason you use tracers in a belt of ammo is because it allows you to operate a machine gun without using the sights. You just watch where the tracers are hitting and correct on the fly. A large man with exceptional strength may be able to do something like that with a "big fifty". There are some things you would need: for one, a .50 doesn't usually come with a buttstock, and the trigger is set up wrong for carrying in this way, so you would have to have the trigger mechanism replaced and a butt added to the end. In addition, you would want some kind of plastic grip for the body, so you don't have to hold a VERY hot piece of metal right up against you while firing. You would also want something to direct the hot brass away from the soldier, because having a hot .50 caliber case land on your neck is NOT fun. *Shouldering* a conventional fifty caliber is probably not going to happen regardless of your "super soldier"'s strength unless he was considerably larger than a normal man. This is simply because of the weight of a .50. A very large amount of that weight is the extremely heavy barrel, which, if you were to hold the thing the way you would hold a hunting rifle, would make it impossible to stand upright unless you weighed over 300 pounds at least. When I was in the paratroopers, I was 230 lbs of solid muscle and there is no way I could have held one out like that. I'd say you would need to weigh closer to 400 pounds just to balance the thing. Figure maybe 7 and a half feet tall plus. But a very strong and large person could fire it the way I described; the same way a normal man fires a conventional LMG. One thing to keep in mind is that the US Army is currently starting to roll out a second generation .50 machine gun which is supposed to be significantly lighter than the original. Whether this retains the incredible reliability and indestructability of the original fifty is unclear. The reason the original design was basically unchanged since WWI is because it is designed for *sustained* *fire*, unlike almost anything else a platoon of infantry has. Even my (lovely, wonderful, awesome) 7.62mm machine gun would eventually get some pretty serious heat issues after keeping up sustained fire for more than a couple minutes. Any assault rifle is in no way designed to handle sustained suppressive fire -you try that with an M-16 and you will *melt* it. The .50 on the other hand, is designed to just keep on firing and firing as long as you need it to and can keep feeding it (expensive) ammo. That's why the metal it is made out of is so darn thick: it doesn't warp at extremely high temperatures. Switch out the barrel and keep on rocking and rolling. The trade off is it's heavy as all hell. Realistically, you don't need a guy to be carrying around something that can keep up sustained fire like that because there is no way that guy can carry enough ammunition on him to feed the beast. I remember when I had to hump ALL my own ammo at one point on an overland march (you are supposed to have 2 guys for each machine gun so one guy can carry the ammo) in addition to the actual "Mag". It was insane, and even being barely able to move with over 100 pounds of ammo on me, that was barely enough to keep up a sustained fire for a couple minutes (if I remember right). With a .50, you have geometrically fewer rounds in the same size ammo box, because they are so huge. That means that a human sized person (or even one somewhat bigger than normal) just can't carry that many .50 cal rounds on them, and there is no way they would be able to walk anywhere and then keep up a suppressive fire for more than a minute because they would run out of ammo before then. That means you don't need a beast like the "Ma Deuce". Think of a cross between a Deuce and a Barrett. Something that most of the time works semi-auto. Basically a really scaled up assault rifle. It would be much lighter and let you shoulder it properly. I can see the usefulness of a .50 round in some situations, but a soldier would be able to carry a LOT more 7.62 NATO, and those have more than enough penetration for most things they would need to do (unless your aliens have some serious natural armor or something). I could see your guys using a scaled-up 7.62 assault rifle, maybe with something interesting like a pump-action grenade launcher on the bottom (too bulky to work on a regular assault rifle for normal people). Maybe a single guy on the team with a somewhat chopped down .50 machine gun for support. ]
[Question] [ I'm interested about whether or not and how gravity would be affected on deformed planets. You could think of this as whether or not mega-asteroids would be able to sustain life? If so, would different parts of the world contribute to different ecosystems due to the shape of the planet, or would life evolve differently in different areas due to the gravity? I'm thinking of making a planet that was conjoined by another planet, forming a peanut-shape in appearance. The idea is that these planets formed around same time, and in a similar orbital distance so that over time they would eventually, and passively collide and conjoin with one-another? Similar to this [link](https://worldbuilding.stackexchange.com/questions/8772/can-a-nonspherical-planet-exist-and-can-it-be-habitable) but rather about the specifics of a peanut-shaped world. [Answer] From an engineering perspective, I don't think your planet can exist. The problem is that two planets even of Mars size that came that close would ultimately collide violently, not just fuse at the outer edges. If that happened, you'd likely end up with one large planet, and a close moon of proportionately large size. In point of fact, we [believe this has already happened](https://en.wikipedia.org/wiki/Giant-impact_hypothesis) in our solar system, closer to home than you might realise. In a peanut shaped planet hypothesis, the 'narrow' band between the two conjoined planets would have to be extremely dense and strong to stop the two globes from pulling more towards each other. Even assuming that this was the case, the amount of tectonic pressure on the surface of such a planet would be extreme and that would mean massive volcanic eruptions and the like on a regular basis. Depending on which axis the rotation of such a planet occurred, there would also be problematic weather patterns and potentially even issues retaining an atmosphere in the first place. If it spun with the two globes effectively orbiting each other for instance, the angular velocity at the 'equator' points could be enough to lose atmosphere to space in this model, although I haven't run any math to prove this hypothesis because it would depend on the size and mass of both planetary 'halves' and the length of the conjoining piece. Ultimately, I suspect such a planet would either rip itself apart and reform as a planet / moon pairing, destroying all life on the surface in the process (but potentially providing a world for new life to form on more conventionally). **But for the sake of argument** If I was to design such a planet, the only way I can see that it could have formed in the first place and maintain its form would be two celestial bodies that were approaching each other from opposite directions VERY quickly. This means that one would have to have been orbiting the sun in retrograde; perhaps an extra-solar capture? Then, instead of colliding head on, strike each other in a glancing blow. I need to stress here that even this would likely result in a massive collision that would break apart both planets, but in this case I'm going to suspend the hard science disbelief and speculate a little. Let's say for the sake of argument that the planets were travelling SO fast past each other that their mutual gravitational pull spins them together and converts the momentum between the two planets into angular momentum between each other. It's *possible* that you could end up with the planets close enough to fuse, but for the spin being generated to be sufficient to keep the two cores apart. This would cause the rotation of the planet to be on the axis describing the fusing of the two planets, meaning that they would continue to 'orbit' each other very quickly, counteracting the gravitational force pulling the two planets together. If this happened, the planets would have to be spinning so fast that I doubt they could collect a reasonable atmosphere. That may not exclude life, but it would exclude land based complex life. That said, it's again *possible* that you could retain some form of ocean (water is thousands of times more dense than gas so less subject to being flung away) although this kind of rotation would lead to pooling water at both extreme ends of the 'peanut' which essentially forms a fragmented equator (this effect happens on the Earth today which is why there is not a lot of land right on the equator of the Earth). These two 'oceans' could allow complex aquatic life if you had ocean flora oxygenating the water, but you'd probably find two completely different evolutionary habitats on both peanut ends. It's unlikely (unless you can somehow put an atmosphere into the middle of the peanut) that you would have any life traversing between the two different biomes. Additionally, the two bodies effectively orbiting each other would mean that their cores could build up a MASSIVE spin, generating an incredible magnetic field over each end of the peanut. If those fields were harmonised, it would be a very interesting field to 'see' and would further support any extremophile life on that planetary body by keeping out cosmic rays. If they were NOT harmonised (far more likely) the auroras and the like visible from the fused area of the peanut planet would be simply spectacular. You'd have a tourism industry built in right there. Ultimately however the angular momentum would ultimately start to fade and you'd have tectonic instability and the planet would eventually collapse. Even the Earth has slowed considerably in its rotation since the event that created the Moon, showing that in time this model would prove unsustainable. That said, it could take a billion years to finally collapse. In that time, both biomes described already could have some interesting life forming in them (that would ultimately not survive the collapse) [Answer] Precisely how such a world would form is, to say the least, tricky to work out. Two planets colliding without first being captured into each other's orbit certainly wouldn't do it--at least, not in one step. Such is a collision is *anything* but "passive"! As Tim B suggested, it's much more likely to result in vaporizing a large portion of both planets, and creating a ring system and/or moon. If the resulting moon is sufficient large, however, such that you essentially end up with two *new* planets orbiting each other, that might be a good place to start. Or some other method of capturing two planets into each others' orbit. At that point, you just need some mechanism to rob angular momentum from the system, slowly drawing them closer together, until they distort under their mutual gravity and begin to merge. They have to be pretty close in size for this to work, as otherwise one body will simply break apart into a ring system when it crosses its Roche limit with respect to the other one, and draining enough angular momentum through natural processes is left as an exercise for the reader. All in all, though, I would gloss over how the planet came to be in the first place, leaving that as a mystery (perhaps even one that you hang a lamp shade on, just so readers know you know that it's a thing, and are purposefully leaving it out rather than being oblivious), and focus on the features of the world *as it is*, assuming that it *does* exist. After all, that approach worked fine for Robert Forward in *Rocheworld* (aka *The Flight of the Dragonfly*) and sequels. The "neck" of a peanut world does *not* have to exceptionally strong. In fact, it can be made of anything at all--even water, or just air (in which case, the system is conventionally known as a rocheworld, like the eponymous novel). This is because a peanut shape is in fact a gravitational equipotential surface; i.e., every point on the idealized surface is at the same gravitational potential, and doesn't want to "fall" anywhere, so no structural strength is needed to support it. That also means that water will not preferentially flow to any particular major region, and you can realistically put oceans anywhere you want. As far as the water is concerned, there is no reason to flow to the outer poles over the neck, or vice-versa. They both have the same gravitational potential. Now you might think "that makes no sense! Surely the two lobes are gravitationally attracted to each other!" And indeed they are. The catch is that such an equipotential surface *only exists* if the body is rotating sufficiently rapidly, such that centrifugal force balances that mutual attraction. In effect, the two halves must orbit around each other, close enough that they are touching. And we do in fact know of astrophysical objects that act like that--they are called over-contact binary stars, and they are indeed stars shaped like peanuts (the processes that form over-contact binary stars unfortunately are not easily applicable to solid planets). In fact, above a certain minimum spin rate, the oblate spheroid shapes that we typically associate with planets become unstable--so if you can figure out a way to start with a normal planet, and then spin it up to ridiculously high speeds, that would give you a way to form a peanut-planet. So, the peanut planet will of necessity have *very* short days. Like, on the order of minutes rather than hours. As such, you are unlikely to get lifeforms adapting to the diurnal cycle like they do here on Earth. The neck region, and generally all non-convex or inward-facing parts of the peanut (i.e., every part of the surface that is not contiguous with the entire surface's convex hull), will also tend to be colder than the outward-facing poles--and this is in addition to the usual decrease in temperatures towards the poles--because they are shaded by the mass of the lobes. You can also expect some pretty weird wind patterns, due to the combination of high spin rate, non-trivial shape for air to flow around, and non-trivial heat distribution around that shape, but I have nowhere near the expertise to describe them precisely. At the very coarsest level, however, assuming the planet is roughly as "thick" as Earth, through the short axis of one of the lobes, I would expect more and thinner (i.e., covering fewer latitudes) major circulation cells, with stronger prevailing winds. Coriolis effect would also be intense, so you can expect lots of cyclonic storms, but not huge monolithic hurricanes (because if they got too large, they would have to cross cell boundaries). Now, the surface is an equi*potential*, but that does *not* mean that there is equal gravitational *force* everywhere. Force is the gradient of potential, and while the value of the potential may be the same at every point on the surface, it's gradient is not. You would have the highest gravity at the north and south poles of each lobe, and lower gravity along the equator. Additionally, gravity will decrease from the exterior poles along the equator to the center point of the neck. The lowest gravity would be at the center of the neck on the equator, with the poles of the neck having slightly higher gravity. Depending on just how stretched out vs. squashed together this particular peanut is, the total differences could be very large (like, 2gees at the lobar poles, and a tenth of a gee on the neck), or relatively small (like, say, 1/5th of a gee difference between the highest and lowest gravity areas). The more stretched out the planet is, and thus the higher the variance, the more you would expect both animals and plants to be specially adapted to specific gravitational conditions. Note that the lowest gravity areas, however, are relatively small; the gravity drops pretty rapidly as you move from the convex inner surface of one lobe to the concave surfaces leading into the neck. While the two lobes could have significantly different average gravity between them, the total variance in gravity *on one lobe*, outside of the concave neck regions, will be fairly small. Addendum: it may seem that the high rotation rate of such a planet may preclude holding a particularly thick atmosphere, since at some altitude any co-rotating air would be in orbit, and above that altitude it would be actively flung away. The trick is to ensure that the planet as a whole has a sufficiently high escape velocity, and sufficiently distant lobar Lagrange points, that you can keep a suitably deep atmosphere below the escape level, and ensure that a high fraction of air molecules that may escape one lobe nevertheless remain in orbit, to be recaptured later (this is similar to the gas torus phenomenon seen around gas giant moons, notably Io). In the case of a rocheworld, where the bridge is entirely made of air, the Lagrange points are necessarily inside the atmosphere; I am not certain how to explain in detail how such a world is capable of retaining air over the long-term, but Robert Forward thought it was possible, and I'm generally willing to defer to him on such matters. Additionally, the fact that the previously-mentioned over-contact binary stars are not universally surrounded by spiral nebulae is real-world empirical evidence that peanut-world can retain gas, even when the lobar Langrange points are *inside* the gas envelope; you just need a large escape velocity, which does *not* necessarily imply a large surface gravity, especially when you have the total mass of two lobes contributing to their mutual escape velocity, but not to each others' surface gravity. ]
[Question] [ I'm about halfway through a novel about a very advanced alien civilization that is systematically wiping out other species using engineered viruses. I am hoping to have the protagonists test samples in order to prove that the viruses have been designed, and then confront the designers, but that's where I need some input. Other than the fact that these are novel diseases that are unique to each species, would it even be possible to identify signs of unknown modifications in an organism - specifically a virus? My hunch is that there would be no way to tell simply by analyzing the genome, but I could be wrong. Apparently our current technology does not allow for this level of identification, but a sufficiently advanced culture might be able to do it. Currently, I am leaning towards explaining this with a lack of junk-DNA in the engineered viruses, or perhaps some specific promoter or terminator that is known to be used by the designing aliens. A clever group of scientists should be able to anticipate these problems, however, and mask them within the genetic code. Any other ideas? I am a biologist, so hit me with whatever science you like, but I am not an expert in genetics or diseases which is why I would like some feedback. [Answer] I think the best answer might be the one you supplied yourself -- that is, the lack of junk DNA. The engineered virus might just be too ... slick to be natural. Another thing to look at is the shell of the virus (if it has one). Many viruses have a protein shell. Perhaps the alien virus' shell has unusual compounds not seen elsewhere on Earth, perhaps it has some non-protein structures mixed in. Check here for some coolness: <https://en.wikipedia.org/wiki/Capsid> I like this option because the shell is discarded upon cell entry, so it can be almost as weird as you want without making the DNA too weird. You might go the other way; maybe the alien gene engineers did use their "native" viruses and for economy's sake (hey, there are a **lot** of aliens to destroy, and we're on a budget) they *didn't* cut out the junk DNA. So that junk DNA might contain exotic nitrogenous bases, not just your boring Earth adenine (A), thymine (T), guanine (G) or cytosine (C). Admittedly, this is a toughie, because a virus is a pretty cut-to-the-bone pseudo-organism. There's not much you can change about it and still have it work to infect Earth cells. I'd thought about making the phosphate groups that comprise the side of the DNA "ladder" (the bases ATGC are the rungs) have a different structure, but then the DNA polymerase might not be able to grab on and unzip... Short story -- the easiest methods to make your virus still work but be exotic enough to call attention would be no junk DNA, or an exotic shell. **Update after comments:** There was a question as to whether viruses have junk DNA at all. I couldn't find a definitive answer (I'd made the assumption), because the notion of "junk DNA" is being challenged right now. I did see this interesting article ( <https://www.ncbi.nlm.nih.gov/books/NBK8439/> ) which discusses classes of mutations in viruses which do not cause a change in protein expression, so I'm hopeful. [Answer] A natural virus will show a family resemblance to other strains. There will be a few changes that explain why it suddenly appeared to us (effective virulence or zoönosis). We will be able to see an evolutionary path from *old* to *new*. Think of running a diff between versions: you can change a single code, delete runs, insert runs (if you find the source of the insertion: duplicate other parts or a different virus or from the host?), cut/paste from one place to another. Now that is really a roll-up of many individual checkins. Just as with code, every checkin must *work* and be infectious and reproduce. With some pondering, we can figure out the individual checkins and some order dependencies among them; with more work (and searching for more wild strains) we can figure out that something was changed and changed back later, enabling the versions inbetween to function. Individual changes are small *changes*. Furthermore, nature is a sloppy engineer, as the expression goes. Consider the revision-control repository analogy again. Look at a codebase history, and you can see lon stretch where it’s stable, then spot changes made by maintenance coders just fixing the immediate cause of a bug without deeper understanding of the code. Then a checkin where an engineer was tasked to *really* update it. It's fundamentally a different appearance in the diff, and quite obvious. So, if the virologist finds that the code has been **refactored**, cleaned up, and entirly new chunks added (rather than copied from somewhere else), it will be obvious that it was intelligently engineered. And that is how you can explain it in the story. It’s obvious to the virologist, and she trys to articulate her reasoning to others. [Answer] Do it the way computer security experts identify digital viruses. These aliens have certain *patterns* for their virus they use again and again. * The genetic code how the virus blends into the immune systems of various species and how it hurts them is different each time. * The code which holds it all together, and how the virus replicates itself, is exactly the same. * There might be "kill switches" to prevent species-hopping or to make the virus self-destruct after a certain number of generations. This could be replicated as well. Perhaps that's integrated with the replication code -- this virus is really resistant to random mutations, *except* for the stealth shell which is allowed to mutate normally (or even more quickly) to defeat vaccines. What is the likelihood that a dozen different viruses, all from different species, have **exactly** the same sequence several [kilobases](https://en.wikipedia.org/wiki/Base_pair#Length_measurements) long?? [Answer] Thing is viruses are a part of an established ecosystem. Your viruses are used for genocide, therefore they have to be terribly effective at three things: 1. Virality or how quickly and effectively it spreads among specimens. 2. Lethality or how effective it is at killing infected specimens. 3. Tenacity or its' ability to persist despite immunity adaptations and consious attempts to cure it. First two already contradict each other if both have to be achieved in a short time frame. The third would make the virus too complex or alien to the ecosystem at question. In order to achieve all three goals your virus would have to be way too different from current or past stamps of viruses and therefore would not have an evolutionary lineage marking it as artificial. From an analysis perspective it would look like: "Well we had that flu(virality) stamp that was pretty nasty, but 'suddenly' it acquired the traits of ebola(lethality) and hiv(tenacity). Something ain't adding up, man, I think we should discuss this issue at the Galactic Council." You can try and bypass this by saying that there already exists a mega virus that posses all three traits and only changes targets in a single evolutionary adaptation, but in such case virtually everybody would try to study it and defeat it before it targets them. Possibly they would even monitor its status making any attemepts to mess around with it result in the same consequenses as WMD proliferation. ]
[Question] [ Could a continent roughly the size of Europe, Africa and North-America combined be formed almost entirely due to volcanic action? [![enter image description here](https://i.stack.imgur.com/wMmPN.jpg)](https://i.stack.imgur.com/wMmPN.jpg) Something with a similar formation to this. From a chain of volcanoes the size of Yellowstone maybe? Sprouting over a platformy/plate thingy (can't remember how it's called right now) already in existence. the volcanoes do **not** need to be active. Actually they need to be old enough to not be active. [Answer] Short answer no, long answer maybe you could create that much landmass but it probably wouldn't be contiguous, also the continent kind of has to be there already. Take a very large, shallow sea, thousands of square kilometers in all, add 2500 cubic kilometers of ash and debris (roughly what erupted from Yellowstone 2.1 million years ago) it's going to be a more or less circular distribution slightly distorted by prevailing winds and thickest in the centre. There would by definition have to be continental crust under the sea in the first place or it wouldn't be shallow enough for the ash and debris to raise the surface above sea level, a bit like New Zealand's underwater continent; the huge area of continental rock out to the East of the South Island. [Answer] Yes. And yes, there is an example in our solar system. It actually exists. Except that there are currently no oceans. But when there were, it would have been. It's on [mars](http://geology.com/articles/highest-point-on-mars.shtml). > > The highest point was built by repeated eruptions of Olympus Mons, the > largest volcano in our solar system. Although Mars is a smaller planet > than Earth, the heights and depths of these features are enormous in > comparison. > > > A volcanic mountain over 13 miles high. Does that qualify? [Answer] A single volcano would definitely not suffice to create a continent of such a size. You would require a ring or chains of volcanoes to create a larger structure; you may look for example at japan for comparison of creating a larger archipel in such a way. Volcanic eruption in itself would however not be enough to create a whole continent, in particular not of the size you want. Without plate tectonics and large land masses pushing up the continental surface from underneath the sea level, the formation of such a large continent is impossible. You can compare the 'super-continent' Pangaea from earth's own history. [Answer] technically all continents were formed by volcanic activity in the planet's early history, of course the term volcano does not mean much wehn the entire planets surface was lava. But I assume you are talking about in modern times, in which case the answer is not without killing every living thing on the planet. The best you can manage is something the size of the [deccan traps](https://en.wikipedia.org/wiki/Deccan_Traps) but you are still talking about a mass extinction event. Yellowstone is a hotspot induced composite volcano these can only occur on an existing continent otherwise you end up with something like Hawaii which you can see is not enough to produce a continent. Even with multiple eruptions the biggest you can get is something like the deccan traps or possibly Iceland or Japan. Volcanoes are rather tiny compared to the continents. [Answer] Yes. It is perfectly possible. I can name an example. The Tharsis Bulge, which is the is the size of North America. The Tharsis Bulge is one giant volcano, in fact. The world would need to have little to none tectonic activity, like Mars, but its volcanic activity could be crazy high. These would be the type of continents to form on Bathypelagic(normal earth ocean depth) Oceanic worlds, as no tectonic activity is why Bathypelagic Oceanic worlds exist. ]
[Question] [ ***I wonder if a political system without a permanent government is feasible.*** I am thinking about a combination of a [direct democracy](https://www.wikiwand.com/en/Direct_democracy) with a project-based administration. The citizens are long-lived (200-250 years) but not immortal. The society is isolated, technologically advanced (although, does not have FTL), and relatively homogeneous culturally. This world enjoys [post-scarcity economy](https://www.wikiwand.com/en/Post-scarcity_economy) with no currency: * no taxes; * no competing economic interests; * no private property; * high levels of automatisation and robotisation; * all technologies are environment-friendly as much as possible; * the society emphasises recycling and use of bio-degradable materials. This society started as a small space colony on a bare rock in the middle of nowhere. Ships and domes are used as habitats while the planet is being terraformed. Once it is possible to live on the surface without life-support systems, all citizens will have a choice of accommodation: open-air planetary life, a spaceship/space station, or domed habitat on one of the moons/asteroids/nearby planets. ## Legislation: * Direct legislation via referendum using three steps: 1. initiative (citizens consult with interested groups, propose a law, and collect required number of signatures within a limited period of time); 2. deliberation (a discussion about a proposed law by random representative sample of population); 3. direct electronic referendum. * Referenda can be [mandatory](https://www.wikiwand.com/en/Mandatory_referendum) (constitutional matters, big scale projects, resource allocation, and alike) and [optional](https://www.wikiwand.com/en/Optional_referendum) (special interests, smaller projects, etc.). * Mandatory referenda require a double majority for a law to pass. * All laws must have a [sunset clause](https://www.wikiwand.com/en/Sunset_provision). * Voting is a duty of every adult citizen. * Enforced [compulsory voting](https://www.wikiwand.com/en/Compulsory_voting) for mandatory referenda, non-enforced compulsory voting for optional. ## Administration: * There is no central government or political authority. * An advanced AI (not necessarily sentient or super-intelligent) acts as a replacement for bureaucracy when it comes to referenda, enforcing voting laws, and allocation of resources (as specified by law). The AI is neutral, but the survival of humanity is one of its main priorities (either by will or design). * The AI can participate in legislation using the same process as citizens (and it has 1 vote, which cannot break a tie). * The administration is project-based: + when something needs to be done the citizens organise a committee to supervise the project; + any of the project leaders can be recalled at any time either by 3/4 of the team or through global referendum (depends on the scale of a project); + long-term projects cannot be supervised by the same person for longer than 10 years regardless of their qualifications; + former supervisors can be retained as consultants, but the responsibility for decisions rests with a current supervisor. * Project supervision is a duty. Every adult citizen must participate in administration at least 5 years (not necessarily 5 years in a row). The maximum cumulative time in administrative roles must not exceed 15 years. ## Law Enforcement: * There is no police or any other law enforcing agency. * When needed, citizens can create form a militia. * Misconduct and crimes are dealt with on a case by case basis. * The society prefers rehabilitation to punishment. * Repeated offenders can be banished: + Banishment is not permanent if a person can prove that they are ready to reintegrate into the society. + Banished individuals get minimal resources necessary for survival in the wilderness. + The citizens have a right to kill banished individuals who continue criminal behaviour or endanger community and its members. Killing, in this case, is seen as the last resort and not encouraged, but not frowned upon. It is understood as a sad and unpleasant necessity to protect the society. * The AI is responsible for administrative enforcement such as issuing reminders and notifications or limiting access to certain areas and/or resources. [Answer] Probably not workable, like many such schemes. * No single person can cast **informed** votes on all issues. So most political systems have *representatives* (who will be paid, full-time politicians) and political parties, which help not just with compromise-building but also with specializations. *How to vote on the infrastructure bill? No idea, I'll ask* our *guy in that subcommittee what we should do. I trust him even if I don't have the time to understand the answer.* * Direct democracy works best for questions which can be answered with a clear "yes" or "no" rather than percentage points. * Direct democracy works badly for questions with side effects. *So you want lower taxes? You want a debt limit? You want more defense spending? Hmm, how exactly do you plan to reconcile that?* [Answer] Several people have already dealt with the issue of demagoguery in a direct democracy, and the lack of Law Enforcement, but two other things strike me in reading the OP. 1. There is no neutral arbitrator to settle disputes. The courts of law interpret and enforce laws, but not just criminal law. Contract law is a major part of the court system and contracting parties might be in dispute over varying interpretations of a contract (This gets interesting when multiple parties are involved, for example subcontractors, or partnerships with more than two partners or partners with unequal shares in the corporation). 2. This is advertised as a post scarcity society, so politics in the form we are familiar with might not even exist. In Organizational Theory, politics is defined as a means of allocating scarce resources, but in a post scarcity society, the only truly limited resources left are time and bandwidth. Even banishing a person to the wilderness seems pointless if they can simply use nanomachines, replicators etc. to create a palatial estate surrounded by landscaped gardens and filled with delicious food, artworks and vintage automobiles (or whatever the person desires). In effect, they are living the same sort of lifestyle as everyone else is already living, except they have been blocked on Skype and "unfriended" on Facebook. So I'd suggest you rethink the conception of this society. Perhaps the better way of going about this is to start with the economic conditions (post scarcity) and then consider the consequences including secondary and tertiary effects on people and their relationships with each other (since laws and customs are generally developed to regulate these). From there imagine what sorts of social institutions would arise and how disputes would be settled (which speaks to the issues of law enforcement and the courts). How politics is dealt with in such a society would be drastically different than anything we know today. Even a "point" reputation system like Worldbuilding Stack Exchange would probably not be adequate for the task, although some very interesting scenarios might be developed from that. [Answer] Here is a thought experiment for you. It might help you see all of the ramifications regarding public policy decision making, and lead to an answer. Consider the task of setting a speed limit on a highway. How do you do it? A. Have the traffic experts look at the design factors of the road, and the automobile. Set a speed limit that is safely able to be negotiated. But what road conditions? What automobile? what mechanical condition? What driver skill level? Who and how are these decisions made? Some 'experts' will be more conservative than others. So how do you decide what experts to use? B. Have no speed limit, and let every driver go the speed they feel comfortable at. Some drivers will drive really slow, others will drive really fast. And, like the German autobahns, you then have the requirement to set up medic critical-care stations all along the roadway. C. Do a survey of the speeds drivers currently go at, and take the 80th percentile of speeds, and set this as the limit (or the 90th? Why not the 75th? How do you decide the percentile? Who decides the percentile?) D. Take a vote, and let the majority decide (50%? 60%? 80%? Unanimous? What is the 'winning majority' magic number? How do you consider the minority rights of pedestrians vs aggressive drivers?) E. Use 'pace cars', and everyone has to drive at the same speed as the pace car. F. Use a random number generator to determine the speed. G. On odd numbered days, have one speed limit. On even numbered days, have another speed limit, to accommodate the rights of slow drivers and aggressive drivers equally. H. Have a permanent oversight committee, that determines on a day-to-day, or even hour-by-hour, basis what the speed limit is to be, based on current conditions. I. Have a transient committee that meets ad-hoc, whenever necessary, to look at all of the above factors (road design, automobile design, public safety, generally accepted practices, public input (drivers AND pedestrians, parents of children, other stake holders), and then makes an informed, best practices arbitrary decision. J. Let the drivers decide arbitrarily, or let the pedestrians decide arbitrarily, or let bicyclists decide arbitrarily among themselves, by majority vote? Determining how decisions are made is not a simple process of the 'application of the principles of democracy'. Life is not that simple. You should take some time to get around ALL of the different types of decisions that need to be made in a functioning society. Given the number of decisions that have to be made at all levels (and visiting a city council meeting might be enlightening) one must consider the effects of the loss of productivity that would ensue if every single member of a society had to familiarize themselves with the specifics of every decision that had to be made, take the time to research and discuss it, and then take the time to vote on it. Methinks that, if voting were compulsory, the average citizen would revert to the 'eenie meenie minie moe' method. And remember the old adage - once you give a project-based administration a budget line, that administration becomes permanent, even after the problem is solved or the project is completed. Budget lines have a vested interest in ensuring they remain funded. [Answer] Have a look at the governing structure of indigenous aboriginal populations. John Locke himself came over to North America and was absolutely astounded by the total democracy of the Iroquois Confederacy. He saw it as the perfect example of government by the people, for the people, and a system that fit perfectly with his ideals that the people had the right to determine who governed them. Their form of government had a tremendous influence on his thinking about government by the people. However, his bias and bigotry prevented him from recognizing them as 'humans', as narrowly defined in his white-male-centric ideas. It was a societal system that almost exactly maps the structure you proposed - no permanent on-going government body (a council that came together occasionally, and then 'left the scene', no police force, decisions made unanimously by a vote. It did not have AI, but what it DID have was a system that was overseen by the elders - presumably using their collective wisdom shaped by a lifetime of experiences. It was one of the most pragmatic of societies known to humans. 'The foundation of the Haudenosaunee Confederacy is the Kaianere’kó:wa; more commonly known in English as the Great Law of Peace. This ancient doctrine provides an elaborate and efficient institution of democratic governance, social and economic stability, and a moral equation to achieve peace; both within one’s self and among the populace. It is in every sense the Constitution of the Haudenosaunee; spawning the beginning of republican democracy in North America and inspiring other nations, particularly the United States of America, to embrace this unique ideology that combines a holistically benevolent approach towards peace and inner peace with a exceptional and practical method of civic problem solving.' from [link](http://www.kahnawakelonghouse.com/index.php?mid=1) Except, of course, it was a warrior society beyond its own social structure. Have a look at this web site. I believe it describes exactly what you are after. See also [link](https://www.mpm.edu/wirp/ICW-155.html) [Answer] I don't think this works in a modern society. Even the Athenian democracy was subject to various flaws: Subject to demagoguery -- caught up in the spur of the moment they take a rash action. Not everyone could be an expert on everything. See some of the discussions leading up to the defeat of the Persians. Not everyone participated -- lots of slaves. In a modern world, there are too many special interests, too many topics that take years to get up to speed on. Look at the amount of work that goes into writing (usually badly) one bill. Look also at places that have in essence put in libertarian governments. I suspect you would end up with a bunch of 'tragedy of the commons' scenarios, and a lot of unregulated situations. Consider the state of air and water pollution in the U.S. before the EPA. Emissions controls on cars cost more, but make for cleaner air for everyone. The lack of enforcement will be an issue. One of the ways that Trump is deregulating is by cutting funding and staff to regulatory agencies. Laws without teeth are ignored. In this way the U.S. is following the footsteps of many third world countries. --- However consider an option to direct participatory democracy: Make your vote mobile. Your congress critter represents YOU. His vote is weighted with the number of supporters he currently represents. If you don't like his stand, you move your vote to someone else. There are various high and low tech ways to manage this. An easy way would be a form/post card sent from your local post office. Charge a modest fee for this so people don't do it daily. Say $10. [Answer] As an alternative to democracy, you might have a look at the tenants of technocracy. > > Technocracy is a system of governance where decision-makers are > selected on the basis of technological knowledge. Scientists, > engineers, technologists, or experts in any field, would compose the > governing body, instead of elected representatives.[1] Leadership > skills would be selected on the basis of specialized knowledge and > performance, rather than parliamentary skills.[2] Technocracy in that > sense of the word (an entire government run as a technical or > engineering problem) is mostly hypothetical. In another commonly used > sense, technocracy is any portion of a bureaucracy that is run by > technologists. > > > The term technocracy was originally used to advocate the application > of the scientific method to solving social problems. In such a system, > the role of money and economic values could be less emphasized. > Concern would be given to sustainability within the resource base, > instead of monetary profitability, so as to ensure continued operation > of all social-industrial functions. Some uses of the word refer to a > form of meritocracy, where the ablest are in charge, ostensibly > without the influence of special interest groups.[3] The word > technocratic has been used to describe governments that include > non-elected professionals at a ministerial level.[4][5] > > > from [link](https://en.wikipedia.org/wiki/Technocracy) But it begs the question be asked, how is the selection of the technocrats decided? Who decides? Are they term-limited? [Answer] I think you can make it work, as a piece of fiction. We have no idea what a post-scarcity society will be like, so you can decide what *your* version of it looks like. From the detailed question it seems like you have it well in hand. People can talk a lot about "human nature", but the fact is that all humans up until today has grown up in scarcity conditions and bears the psychological scars from that. We *don't know* what "human nature" will be for human who has grown up in post-scarcity. Also, the science of psychology is still uncertain. In the future they will know more and can use that knowledge to raise children to become proper ungoverned individuals. A few bullet points: * Nothing lasts forever. The (narrative) present is different from the past (narrative past, still our future). The future is different from the present. The only constant is change, and people complaining about it. * Resources are never unlimited. For some things demand will raise to meet supply. Even if nobody owns things, somebody will need to decide how to use them. The right to make that decision will be contested. * In a far future society the most important resources will be physical space and energy. [Answer] Your society doesn't sound feasible with the currently existing characteristics of humanity. It implies that humans have evolved/been culturally programmed to care much more about certain things than they currently do, and simultaneously to care about much less about other things. * For example, in post-scarcity world, why should anyone take up responsibility? Being coerced by AI under threat of punishment doesn't sound like good motivation. * There is no private property, which technically could mean that anyone can go to anyone else's house and start living there. You can have laws against it, but then again, why should anyone bother to enact these laws, unless they are directly affected? * What about dissenters? Humans are not inherently logical creatures. Maybe there will be some who enjoy or support some or many of the things, which are not compatible with your utopia. If they are ostracized, they might just create their own places and cities, and bear hatred for the majority which expelled them. Much of what you propose have been imagined in communist utopia sci-fi, such as by [Strugatsky brothers](https://en.wikipedia.org/wiki/Arkady_and_Boris_Strugatsky) during Soviet times. Very interesting read, their stories set in "the Noon universe" -- a time when much of what you propose (post-scarcity, no private property, etc.) is imagined to have happened. Translated to English as well, I think. In general, however, your world presupposes tightly knit communities, which care enough about each other to do all the things government is tasked with doing. It is not impossible, however, it seems that historically such communities have been limited by size -- people seem to need to know each other personally to care much about them. Indeed, while we sometimes support charities and similar activities, vast majority of us spend most of attention on our beloved ones, relatives and similar groups which make up the inner circle of our world. Post-scarcity may change that, but still any person has at least one limited resource, as indicated by some of the other answers: his attention. Nobody of us can care about every of the 10 million things that make up our world. We select and we ignore the rest. We have government explicitly so that we don't have to worry about a multitude of things ourselves. We have rewards for those who choose to bear the responsibility of governing. All these things seem to be lacking in a world of yours. [Answer] There has been a lot of really good discussion on the best solution to this question. Very informative and useful to a lot of scenarios. Here is some further background information. There has been a lot of study into the benefits and advantages of various leadership styles. Among them are studies that look at problem solving and task accomplishment in groups that have a direct leader vs groups that are leaderless and make decisions by group consensus. The distinct leader groups accomplished their tasks more efficiently in less time, because the leader kept everyone focused and on task. The democratic groups were less likely to finish the task, but the group members all enjoyed the experience more. They were happier, although less efficient, and felt more engaged and empowered. Their self esteem was higher too, if I remember correctly. What a strong central government would do, therefore, is keep the colony on task, and directed to a goal (survival?). Things would be more likely to get done, and in a timely organized and coordinated fashion. A colony that ruled by consensus would be less likely to stay on task, would not be as efficient, but would have happier, more engaged citizens overall. (Remember the tree beings in Lord of the Rings?) There is an old adage that 'A platypus is an animal that was designed by a committee.' In addition, cognitive research indicates that humans naturally want a clearly defined leader. > > A new finding in brain science reveals a curious dynamic — a neural > synchronization — during communication between leaders and followers: > the brain activity of leaders and followers is more highly > synchronized than the brain activity between followers and followers. > > > from [link](https://hbr.org/2016/02/how-leaderless-groups-end-up-with-leaders) although a caveat is that this research was apparently conducted with neurotypicals. Also useful is [When Everyone's in Charge: The Fallacy of Leaderless Teams](https://hbr.org/2016/02/how-leaderless-groups-end-up-with-leaders) > > Holacracy is born of the belief that "traditional hierarchy is > reaching its limits" and that organizations would work better if teams > had more autonomy. In the world of Holacracy permanent management > positions are unnecessary and without them everyone can have a voice > in every process. Except it doesn't seem to work that way. In fact, > for a model that professes to do away with traditional management and > leadership, there are a lot of rules. The Holacracy constitution is > page after page of what these not leaders and not managers must do and > what they cannot do. > > > Thus I suggest an overall leader of some sort, besides your AI (hard to synch minds with an AI), even if the leader is a token, in-name-only, leader without any defined decision-making ability (much like Canada's Governor-General is, on the organizational chart, the supreme leader of Canada). ]
[Question] [ If you live in a town of wooden buildings, [fire can be a big problem](https://en.wikipedia.org/wiki/Great_Fire_of_London). **If you have the luxury of being able to plan the layout of a city, how do you plan the city to avoid major fires?** Notes: * Low-tech doesn't mean low-knowledge. For example, they could be rebuilding after a fire wiped out most of the city, allowing them to start fresh with fire prevention in mind. * Water is not scarce. Low-tech cities are likely to be built near a lake or river so as to ensure sufficient water. * Other building materials are probably available, but not as cheap or plentiful as wood. * The city is compact - a lot of people want to live in a fairly small area. [Answer] City planning was always the key to prevent big fires. Each time after a devastating fire ravaged a city, like [Great Fire of London](https://en.wikipedia.org/wiki/Great_Fire_of_London) in 1666, leaders were thinking about how they can rebuild better. Generally, there are few important considerations: 1. Wide and straight roads. They would stop, or at least slow down the fire, as well as provide quick access to fire brigades and improve evacuation; 2. No building cluttering and no slums; 3. Easy water access throughout the city - there must be a well, or cistern, or body of water within quick reach from every block. Other things, like professional fire brigades with fire watchers are also beneficial. Switching building from wood to brick or stone is also good, but looks like you want prevent it in your scenario. [Answer] **Plan I**: evacuate all the poor people from the more elevated parts of town, build your palace and rich friends' houses up there. For preference out of brick. Nice wide streets, aqueduct water service, sewer. Surround this precinct with stony zen gardens, plazas, stone basilicas and so forth. Life is golden! Let the poor people build their wooden hovels down below. Learn to play the tibia utricularis and when the town burns down, get down there and buy up the land from the dispossessed; sell some on speculation; build more wooden apartment blocks and charge rent on the rest. Occasional fires are good for forests and cities alike. Burn out the dead wood, so to speak. Well, this plan avoids major fires up there on the Palatial Hill where it's important, eh wot? **Plan IJ**: tile roofs and cladding, especially along the perimeter of a block or precinct. In conjunction with relatively wide streets, this should keep many fires from spreading far. Blowing cinders that land on the roof will cool and cause no great harm. Wide streets (at least between blocks & precincts) will protect neighbouring buildings as well. **Plan IIJ**: urban sprawl. Build several small citylets in close proximity, perhaps surrounded by farm land or orchards and with the civic infrastructure at the centre. When Mrs. O'Leary's cow burns down one residential precinct, the others, owing to their distance from one another, will be left intact. **Plan IIIJ**: Hobbiton. Build your city near the water source, but up in the hillsides above. Dig smials and line them with wood panelling. Impossible for a fire to spread from one house to another, on account of the intervening earth. Round doors optional. [Answer] If water is readily available I see no reason why it would not be a major part of fire suppression. The other main thing to consider would be increasing the distance between buildings to stop fire from jumping to neighboring buildings. I can't really see any reason to get more elaborate than that, water has always been the best low tech solution for preventing fires. [Answer] **Brick.** from <http://fox2now.com/2017/08/14/why-st-louis-is-built-of-brick/> > > St. Louis, MO — It's not the easiest way to build a house, nor the > cheapest, but beginning in the middle of the 19th century St. Louisans > decided to stick with brick. Part of the reason was under their feet. > > > "There were huge clay deposits in there and so that really made it > possible to create brick on site. Then the other impetus for this is > the Great Fire of 1849 which burned down really the entire St. Louis > downtown and led to the passage of ordinances that really required > that more construction be brick," said Dr. Robert Archibald. > > > I suspect brick businesses made sure that their legislators passed this ordinance. I know Chicago passed a similar ordinance after the Chicago fire. A city next to a natural water body probably has clay available like St Louis did and so bricks would not be prohibitively expensive. Available coal helps too, or you can use your wood to make charcoal to fire the brick furnaces. [Answer] If water is not scarce, then build canals. They'll provide handy transport links around the city for bulk goods (on barges or rafts). In addition they make good firebreaks, and are a ready source of water for locals to throw onto fires. In posh areas, have 'water gardens' and 'lakeland parks' instead of canals. The city council can make laws saying all buildings over a certain size must have water troughs outside for animals to drink from, and/or a water pump for humans to drink from. These are an additional source of water when fire breaks out. Lots of big town squares, which are cobbled or paved. People can erect temporary structures here, such as market stalls, but no-one can build anything permanent. Again, these act as firebreaks. ]
[Question] [ **How it begun:** In my world, the surface has become inhospitable due to the ozone layer depleting and excessive levels of air pollution. Life migrated to a giant cave (roughly the size of north America) constituted of many "zones" of varying size connected by tunnels. Most of the zones have access to light through holes on the ceiling filled with glass (filters UVA and UVB). Many biomes are present throughout the cave from volcanic ones to "oceans" (giant aquifers) to plains (with grass and everything). **Where we are now:** It's been a few thousand years since the surface has been abandoned and populations' genes pool have strongly derived. They are not exactly different species (they can mate and give birth) but they are very different physically. **The civilization:** One of these populations are the Sub-sylvans (think elves basically) and they migrated to a forest biome. Initially, the soil was just hard rock and the ceiling was dirt from which trees were growing upside down. The Sub-sylvans made their homes in those trees to avoid predators hunting on the ground and not live in obscurity because the leaves were blocking most of the light coming through the ceiling. **The issues:** First of, fruit creation takes a big toll on a tree so it wouldn't make sense that those tree would make any especially because you don't want the seeds to drop on the ground but on the ceiling. Second, the only reason trees grow tall is to take the most light in real life which wouldn't be the case in my setting. My answer would be that the trees get their water from a ground fog. The lower the moister. Third, because of the leafs blocking the light, agriculture isn't an option. Fourth, hunting could be an option but it'd be very dangerous and they'd not be able to properly cook the meat because of the ambient moisture. **Question:** Those are the problems I am having with keeping the tribe alive and in that particular biome. How do the Sub-sylvans survive and sustain themselves in this environment? --- The level of technology is what you'd see from medieval civilization. They have gunpowder if needs be. There are a few remains of advanced technology from the surfaceans (Nanotechnology) so if it can help them I am willing to accept the answer. They are in very bad terms with the other 2 principal tribes and trading with them is not a viable option. The other 2 factions would rather let them starve and take control of the zone afterwards. I would rather they did not simply cut some trees to make room because they basically worship the forest. It could be a last resort solution and I am hoping to use something else. They also know that the whole wasteland surface is due to the surfaceans cutting trees all over the place without any concerns. [Answer] As said in one comment your world as-is won't work due to lack of light and other problems. Caves with (semi) natural (glass-covered) openings will not allow for a rich forest (inverted or not). If You enlarge too much the openings you'll have structural problems with both the transparent "windows" and the cave ceiling. Even ignoring that any "window" (especially if near-horizontal) needs to be cleaned, otherwise dirt will accumulate till it's not transparent anymore, there's structural problem with large glass structures which tend to crack when under the (huge) pressure given by normal Earth crust movements (no need for real earthquakes). You could change the setting putting a huge forest on the surface and having the roots penetrate in the caves and feed some parasitic vegetation (fungi?). You can have Your elves to live in this strange looking underforest composed by fungi and likens, in a very soft light even by day. "real" plants could grow in patches near the "windows" Fungi could be symbiont providing something useful to the forest. Please note real caves have the ceiling composed by (bare?) rock and the floor covered with mud. There's good reason for this as any underground cavity with ceiling composed by dirt would collapse quite soon. Roots should enter the cave from crack in the rock or have some specific system to "drill" the rock themselves (some roots have this capability). [Answer] Make them eat leaves. In a world with this kind of forest and well into the future, a lot could have changed. I do not know what your humans did before destroying your world, but maybe they even did some genetics to make those two options even more realistic. Maybe they invented this to solve some kind of hunger problem. Maybe it somehow evolved naturally, just like an fantasy underground upside down forest did. You can do this in two ways: 1) The leaves of those magical trees are enough even for us humans. There are already several plants that get eaten by humans, take spinach for example. Those trees might have even more nutritious leaves. 2) We are dealing with a new species here. Make it possible for them to digest cellulose. That way they can just eat whatever plant you want them to eat. In both cases, you should consider them eating some additional food, insects for example come to mind or some roots - just to supplement their nutrition. They are human after all. [Answer] **Maple syrup beer.** I propose your upside trees make loads of sweet sap, which the elves tap as though it were maple syrup. This fits with the tree worship angle: just as the Hindu religion venerates cows because they nourish us with their milk, the trees are mothers which nourish with their milky sap. Living on syrup would be a very low protein diet. The solution: **beer**. Yeast can make all the amino acids we need given some sort of nitrogen to work with. In regular beer this protein basis comes from malt. Your elves could use cave biofilms, which are microbial communities with the power to fix nitrogen. [![http://www.drainfreak.com/df/twincities/landmark/index.htm](https://i.stack.imgur.com/YF6Xn.jpg)](https://i.stack.imgur.com/YF6Xn.jpg) <http://www.drainfreak.com/df/twincities/landmark/index.htm> Plus the cave slime gives the beer that great cave flavor. This yeasty beer, perhaps garnished with some leaves mint julep style, would be all the nutrition the elves need. Visitors attending upside-down elf parties should come with a harness and strap in, because when you are drinking it is hard to keep up with these elves and easy to lose your grip. ]
[Question] [ First of all, this website is a dream come true. I'm a total sucker for this stuff. Secondly, I love astronomy and worldbuilding, and lately, I've been thinking of a hypothetical situation, and was wondering if such a thing was actually possible. A planet orbits a gas giant. Let's say (for reference's sake) the gas giant is Jupiter, and the planet is Earth. Earth is tidally locked to the gas giant, and has a rotational period of exactly one year. However, let's say it also orbits around Jupiter in exactly one year as well, which means that the planet is cooked on its surface for a while and then vanishes into total freezing darkness behind Jupiter every 6 months, give or take. This itself is doable. However, would it be possible if Earth was still located rather close to Jupiter, in a way for Jupiter to still [dominate the sky](http://3.bp.blogspot.com/-pw8qysjJD-M/TrxIa7Vt1NI/AAAAAAAAAKU/Ohv720hScuM/s1600/RingsFromSurface2.jpg) (yes, I know that's not Jupiter)? Of course, it depends on where you're standing on hypothetical Earth to see hypothetical Jupiter, but in this case, we're standing in the right place to expect a giant planet to cover most of our sky. But gas giants' moons orbit around them incredibly fast because they're so close and they have such a strong gravitational pull, which creates a problem, because the ideal orbit here is a slow trip around. Would other factors be able to slow down the planet's course around this imaginary gas giant and create this situation, such as other moons or planets, size of the planets in question, density of either planey, rings around the gas giant, etc., without the planet being pulled into this gas giant? We can ignore the more technical things, like the radiation belt around gas giants and whatnot. The most basic question is if an orbit such as this is feasible. I'm asking for a world that's not Jupiter or Earth, so anything goes if it makes it possible- as long as a big gas giant has a moon. I've ran this through my head a lot, searched for answers, and even bought and messed around in Universe Simulator 2 a little (but it's more fun to blow up planets), and still haven't been able to come up with much of a solution. I'd hope that with the right blend of factors, this would be possible, but I'm not too sure on how this could play out. [Answer] # A 1 year long orbit around Jupiter does not work Orbital mechanics is actually pretty straightforward mathematically. There are rigidly defined formulas controlling what can and cannot happen. The formula for distance of the less massive body (Earth) from the more massive body (Jupiter) [is given by](https://en.wikipedia.org/wiki/Orbital_period#Small_body_orbiting_a_central_body) $$a = \left(\frac{GMT^2}{4\pi^2}\right)^{1/3}$$ where $GM$ is the standard gravitational parameter of Jupiter ($1.27\times10^{17}\text{ m}^3\text{s}^{-2}$); and T is the desired orbital period (1 year = $3.15\times10^{7}\text{ s}$). Plug those numbers in and we get about 15 million km. First off, this is not going to work for your desired 'closeness' to Jupiter. Jupiter has a radius of about 70 000 km. Using simple trigonometry, an object that is 140 000 km across at a distance of 15 million km occupies $$\arctan\left(\frac{140 000}{15000000}\right) = 0.00933 \text{ radians}$$ of arc, equal to about 32 minutes of arc. By comparison, the moon is from 29 to 34 minutes of arc; Jupiter will appear about the same size in the sky than our moon appears to us, in this situation. Secondly, the existing Galilean moons range from 0.42 million km (Io) to 1.89 million km (Callisto). Large moons do not exist that far from planets, at least not in our solar system. I can offer you this chart for the most distant moon from one of our Gas Giants with a mass with order of magnitude X. ``` X Moon Distance 18 Sycorax (Uranus) 12 179 000 km 19 Nereid (Neptune) 5 513 818 km 20 Iapetus (Saturn) 3 560 820 km 21 Iapetus (Saturn) 3 560 820 km 22 Callisto (Jupiter) 1 882 709 km 23 Callisto (Jupiter) 1 882 709 km ``` As you can see, you just don't get large moons that far out. Jupiter's largest moon at 15 million km or greater is about 60 km across. The moral of this story is that it is likely an object as massive as the Earth (50 times again more massive than any Moon) would not stay stable in an orbit that far from a gas giant in a busy solar system. # Conclusion You can use that orbital period equation (and others in the Wikipedia link) to help determine how to make your planets orbital characteristics more like what you want. I would advise trying to make the Gas giant even bigger, there are planets out there 10 times the size of Jupiter. Just be sure to [keep the mass of the gas giant under ~0.08 solar masses](https://en.wikipedia.org/wiki/Stellar_mass), which is the point at which the giant could ignite into a star itself ([Jupiter itself is just under 0.001 solar masses](https://en.wikipedia.org/wiki/Jupiter)). --- EDIT - As @Tradeylouish points out in the comments, even if you made the 'Jupiter' bigger, the increase in mass would cause the distance required for an object to be in a 1 year orbit to increase proportionally; the result would be that the 'Jupiter' would stay approximately the same size in the sky. I was suggesting that the 'Jupiter' be made bigger to help clear the space around it, allowing it to hold onto a satellite at such a long distance. However, this will not help your planet appear massive in the sky. @Tradeylouish's suggestion about density is the way to go if you want the planet to be huge in the sky (though it won't necessarily help keep the satellite in a far away orbit). Density of gas giants a can be pretty low apparently; check out [TrES-4b](https://en.wikipedia.org/wiki/TrES-4b) ([no relation](https://worldbuilding.stackexchange.com/users/11049/tres-2b)) which has about the mass of Jupiter but a density of 200 kg/m$^2$...about the same as balsa wood. [Answer] No. An orbit is elliptic (instead of linear as Newton's First Law predicts) because the planet is attracting the orbitter1. So, we have only the force of the planet applied to the body that orbits around it. Why doesn't that object just fall? Because the pull of the planet2 provides an acceleration; that is, a change in the speed of the body. Instead of flying straight, that acceleration makes it change the direction of its speed, curving its path. Now, we have 3 options: * The body moves so fast that the pull of the planet does not change its speed enough to keep into the current orbit: the body switches to a higher orbit or simply escapes the planet. * The body moves so slow that the pull of the planet changes its speed so much that it cannot keep the orbit; the body orbits are each time closer to the planet. These two points above work as follow: if a body moves apart from the planet it orbits, it loses energy (that goes to compensate the gravitational energy) and slows down. And, at the same time, a wider orbit means that, even if the gravitational pull is slower, it keeps affecting the orbitting body for more time (as the revolution time increases). When the body moves towards the planet it is just the opposite, it accelerates until it finds a lower orbit that fits its new speed (or it crashes). * The body moves reaches an equilibrium speed. The pull of the planet changes its speed enough to keep it in orbit, but without changing it. In a perfect, circular orbit, that could be describe as the body always having the same magnitude of speed (the same km/s) while the direction of the speed is continuously changing by the same amount, enough to follow the orbit. So, it is not as if you can slow the orbitting body somehow. The issue is that, as soon as you slow it, by whatever the means, it begins falling towards the planet, because the only thing that keeps it in orbit is its current speed3. TL;DR The factors that determine a orbit are the speed of the orbitting body and the mass of the body around which it orbits. The only factor that could be changed would be the gas giant mass, but then you have the issue of how making a non-massive-gas-giant (hint, gas has a tendency to run away unless there is lot of attraction from its planet). --- 1 So Newton's First Law is not of application there. Did you thought I was going to say that Newton's First Law does not work? 2Or of any force. 3Technically an orbitting body is *always* falling -the *free fall* term means that- towards the body they orbit, but constantly missing it. [Answer] I found a useful article ["Exomoon Habitability Constrained by Illumination and Tidal Heating"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3549631/1) (Kipping, 2009a). The longest possible length of a satellite's day compatible with Hill stability has been shown to be about Pp/9, Pp being the planet's orbital period about the star. So, if the moon somehow managed to orbit around a giant planet with a period of one Earth year, the giant planet's orbital period around their sun would have to be at least nine earth years. If the moon receives as much radiation from its star as the Earth does from the Sun, and orbits that sun with a period of at least nine years, its star would probably have to be so massive and luminous that it would not remain on the main sequence long enough for the moon to become habitable for humans, develop multi celled lifeforms, or have a native intelligent species. Unless super advanced aliens terraformed the moon and made it habitable and gave it advanced life forms. A very dim star would have its habitable zone very close to it and its tidal forces would make any planet orbiting in the habitable zone tidally locked with one side always facing toward its star in eternal day and the other side always facing away from its star in eternal night. In our solar system astronomers believed that Mercury was tidally locked by the Sun, with one side in eternal day and hellish heat, and the other side freezing in eternal night and cold. But in 1964 it was discovered that Mercury is tidally locked, but not as strongly as a 1:1 resonance. Mercury has a 3:2 resonance. The orbital period or year of Mercury is 87.969 Earth days. The sidereal day or rotational period of Mercury relative to the stars is 58.646 Earth days. Thus there are three Mercurian sidereal days in two Mercurian years. But a solar day, the time between two successive sunrises or sunsets on a spot on the surface of Mercury, is two Mercurian years long, or about 175.938 Earth days. Some astronomers thought that Venus might also be tidally locked in a 1:1 resonance, and some old science fiction stories were set on such a Venus. That is not the case but Venus does have a odd relation between its year length and day length. The orbital period or year of Venus is 224.701 Earth days. The sidereal day or rotational period of Venus is 243.025 Earth Days, longer than the year. All planets in our solar orbit the Sun in a counter-clockwise direction as seen from above the Earth's North pole. Most planets also rotate in a counter-clockwise or prograde direction. If Venus did that its solar day, the time between two successive sunrises at the same spot on its surface, would be several Venus years long and thus more than an Earth year long. But Venus rotates in the opposite direction, clockwise as seen from above Earth's north pole, or retrograde. This makes the length of a solar day on Venus "only" 116.75 Earth days, less than that of Mercury. Nobody knows what gave Venus its long sidereal day and retrograde rotation. A common theory is a giant impact billions of years ago. If the long day and retrograde rotation of Venus have the same cause, it should be rare for a planet to have a long sidereal day like Venus without also having the retrograde rotation, which would make the solar day shorter than the sidereal day. But if the long day and retrograde rotation of Venus have two different and independent causes, it should be much more common for a planet to have a long sidereal day like Venus without also having the retrograde rotation, and thus solar days as long as an Earth year would be far more common. From what I have heard, a planet with days and nights much more than a few Earth days long would suffer from extremes of heat and cold during the days and nights. Lifeforms could flourish only during comparatively short periods near sunrise and sunset. They would have to go into some sort of suspended animation or die and leave protected seeds and eggs, twice each year-long day. Added 04-25-2017. Or lifeforms could move with the sunrise and sunset. With an equatorial circumference of about 25,000 miles and a day about 365.25 Earth days long, animals would have to move at an average speed of 68.446 miles per day or 2.851 miles per hour at the equator. At higher latitudes where the planet's circumference was much less, they could move slower. Where the circumference was only 2,500 miles they would need an average speed of 6.8446 miles per day or 0.2851 miles per hour. [Answer] **Diamagnetic moon.** The problem with this problem is gravity. The orbital math posted above by @kingledion is inflexible. To get a satellite as close as you want and as slow as you want the net attractive force needs to be less. A lighter satellite cannot do it - as Galileo demonstrated dropping the balls from the leaning tower of Pisa. The attractive force is M1\*M2 and when M1 is immense M2 does not matter much. You could make Jupiter lighter but what fun is that? What is required is a force which could oppose gravity such that the net attractive force on the moon was lower. I can think of 2 which might work: electrical repulsion and [diamagnetism](https://en.wikipedia.org/wiki/Diamagnetism). Diamagnetism is magnetic repulsion: the effect that allows certain nonparamagnetic items (like frogs) to be levitated in a strong magnetic field. Achieving levitation means the force of gravity is completely opposed. Jupiter is a good candidate for this because it has a very strong magnetic field. If one starts by accepting diamagnetic repulsion can be strong enough to oppose gravitational attraction on this scale, then for a diamagnetic satellite one could assert that the magnetic repulsion opposed gravity to whatever degree desired. An arbitrarily weak or strong attractive net force would allow your satellite to orbit at whatever distance you like. This assumes that the magnetic field around Jupiter is uniform but if it is anything like Earth's it is not. I could imagine a satellite which sped up and slowed down / moved higher and lower as it traversed the irregularities of the magnetic field and the net attractive force waxed and waned. [Answer] It might be possible to replace Jupiter with more of a cloud, rather than legitimate gas planet. Some sort of star maybe with very low density. I'm not sure if such objects exist, but it might provide the large object in the sky you're looking for. As another answer gave, your distance will have to be 15 million km if your masses are the same (there's no real reason to change the masses). It's hard to tell what you mean by "dominate the sky", but let's go with 5 degrees (0.08727 radians). So, in order for your planet to be 5 degrees large at a distance of 15 million km, you need a diameter of roughly tan(0.08727)\*15,000,000 = **1,312,000 km**. With a mass of 1.898e27kg, your density is roughly 6.7 kg/m^3. In other words, this would not be considered a planet, and I'm not sure if such a cloud could form without it forming together. Possibly your planet has just formed out of the the wreckage of some star. ]
[Question] [ As has been shown many times, once a species "escapes" into an environment, there's no reeling it in. So choosing the right species to terraform Mars is incredibly important. How would we choose the mix of class/order/family? Do we chose just one of each class/order/family? Which bacteria do we chose? Is there a "first wave" of species that quickly get the biological ball rolling, then a second wave to make it all "work" nicely? What about genetically modified species? How restrictive should/can we be? I realise this is quite broad - if you feel so, please feel free to narrow it. [Answer] [Red Mars](http://rads.stackoverflow.com/amzn/click/0553560735) (and its followups, Green Mars and Blue Mars) is the best treatment in fiction I know of regarding the terraforming of Mars. Your objectives for terraforming are primarily to generate an atmosphere. to introduce something that will start making oxygen, while being able to handle the cold and dry and radiation. Both Red Mars and other authorities suggest that lichens are the way to go, and could be adapted to Mars' hostile environment in short order. Lichens should be distributed widely over the planet, where they will start he process of both generating oxygen. The next priority, is some type of decomposer to start turning the dead bits of lichen into usable soil. This would be some combination of fungus and bacteria. After that, you have to wait until conditions get better. This would take forever by its own; you would probably want to hit the planet with a few comets full of useful volatiles like carbon dioxide (to help the plants, provide pressure, and cause a greenhouse effect), water (also important for the greenhouse effect) and nitrogen compounds (to start a nitrogen cycle). Eventually, the combination of heat from impacts and greenhouse effect will start melting the water and carbon dioxide ice caps. Once the planet has some more water, nitrogen, and atmospheric pressure, things would be improved. Vascular plants could survive once carbon dioxide partial pressure gets high enough and water is available. Plants with deep roots, particularly trees, will be important to extract useful minerals from deep in the soil and add them to the available bio-cycles. They will be much more efficient oxygen generators than lichen. Also, if enough liquid water can form lakes or oceans, then various plankton will also contribute a lot of oxygen. That's the moral of the story. I don't see any reason to introduce plants to the planet that aren't wheat, and animals that aren't cows. Why go through all the effort to remake the planet, if you don't remake it for us? --- Edit for [hard-science](/questions/tagged/hard-science "show questions tagged 'hard-science'"): According to [Kass and Yung, 1995](https://www.researchgate.net/profile/Yuk_Yung/publication/15467566_Loss_of_Atmosphere_from_Mars_Due_to_Solar_Wind-induced_Sputtering/links/574cab2808ae061b3301e0ea.pdf), solar wind induced sputtering on Mars could potentially remove 2.4e24 molecules of CO$\_2$ and 8.6e25 molecules of H$\_2$0 per second. This amounts of 6kg and 93kg per second, respetively. This may seem like a lot of materials, however, the Earth's atmosphere is 5.15e18 kg. The ratio Mars:Earth surface area is 0.53, so an Earth-like Martian atmosphere might have mass 1.46e18 kg. For this mass, the half-life at the above rates of sputtering are 500 million years for $H\_20$, and 7.3 billion years for CO$\_2$. Of course, the Martian atmosphere will lose less mass as its density goes down. Instead of losing 6 kg of CO$\_2$ a second, according to [Edberg et al, 2010](http://onlinelibrary.wiley.com/doi/10.1029/2009GL041814/full), quoting Barabash et al, 2009 (which I do not have access to), the actual loss rate in the Martian atmosphere is 0.01-1 kg per second, depending on solar conditions as discussed in their paper. But with a nice full atmosphere, the higher rates of sputtering losses would be observed. The question then becomes, if the CO$\_2$ half-life is 7.2 billion years, then how did Mars lose its atmosphere? This is the purpose of the Kass and Yang paper. The Sun's UV output was higher in the past, even as its overall luminosity was lower. According to their paper, 3.5 Gyr ago, the UV incidence on Mars was six times higher than present, and 2.5 Gyr ago, it was 3 times higher. At these higher UV exposures, the loss rate of CO$\_2$ was about three and two orders of magnitude higher than current, respectively. The conclusion of their paper is that, integrated over 4.5 billion years, Mars has lost about 3 bar of CO$\_2$. However, for our purposes starting in the current day, that loss will not be repeated because the sun's ability to strip Mars' atmosphere is significantly reduced. # Conclusion If we added an atmosphere to Mars, it would take on the scale of billions of years for it to be removed. If we can add an atmosphere in thousands of years, there will be no problem retaining it. [Answer] The main problem with escaping species on Earth is they tend to destroy the local ecosystem. When you're terraforming Mars you don't care about the local ecosystem. Our first big issue is how are we colonizing? Are we slamming large icy bodies into the surface or do we work entirely with the ice we find on Mars? Do we have a thicker atmosphere or is that still being worked on? That would imply how much radiation resistance our species need. Regardless I'm confident our species will be genetically tailored to living on Mars. The first plants will likely be very hardy. Evergreens, moss and algae. Our first fauna will probably be related to keeping those plants alive. Something like worms and moles for the soil. As for what we choose specifically? Whatever is easiest to work with probably. Species A is a great fit the the genetic modification hits a snag? We probably take species B that works almost as well. Time is money after all. Really this question is pretty dang broad. But likely the order will be like this: * some bacteria * some simple hardy plants * some small creatures to support the plants * insects in general * bigger plants * small animals like rabbits, ferrets and lizards * etc. [Answer] Good answers from kingledion & Mormacil. I'd add that humans would be desperate to **exclude** a whole bunch of species from whatever ecosystems they create. We won't want anything which causes disease in us or our crops or our domestic animals, for instance. Or which we just consider to be a nuisance! So no malaria-carrying mosquitoes, for instance - partly because we don't want malaria, and partly because people just don't like getting itchy bites from mosquitoes, midges and the like. So no poisonous snakes, biting insects, parasites, crop pests, garden pests, and so on. This will have all sorts of knock on effects. No midges and mosquitoes means no (or fewer) dragonflies, swifts, swallows and bats, since those all eat flying insects, and fewer lake fish, since those eat the mosquito larvae. No greenfly (aphids) means healthier plants but no ladybirds and none of those ants which 'milk' greenfly for honeydew. Whatever ecosystems we build on Mars will be very species poor compared to Earth. The terraformed planet should be regarded as a giant garden or planetary scale greenhouse rather than as a natural biosphere. Mars may look like pockets of a tidier version of the modern British farming landscape, set in a largely animal-free steppe or forest. Whether wild animals like deer, bison, wildebeest, wild horses and the like roam free will depend on the political clout of agribusiness versus the hunting lobby versus wildlife lovers. Farmers really don't like herds of deer and flocks of finches eating their crops and cutting into their profits. Big predators - lions, wolves, leopards - have a glamorous appeal, but also have a nasty habit of eating our goats and cows, and occasionally eating us. There may be a ban on introducing anything dangerous to 'the wild'. [Answer] All of these answers appear to be decent starts tot the question but even if we could fill out Mars' atmosphere with the necessary gasses (there are many means to do this, very few of which we have established technology to accomplish) the fact does not change that mars' magnetosphere is simply to weak to hold it all stable. Mar's core is completely or almost completely dormant and thus has a weak pull on the atmosphere it is trying to retain. Every time a solar wind comes by, it blasts some of the atmosphere away and some molecules just drift a little to far and float off. If we increased the density of the atmosphere all it would do would be to increase pressure which would make it easier for gasses to get pushed further away and drift out of Mar's reach. Also for clarification purposes from an early post- lichens are decomposers and one of their main purposes on mars would be to break down rocks and minerals into more usable forms in the soil for plants to use. That is why they are so important, not because they produce tons of oxygen on their own- though they would breath out some. Also as for the what species' would we bring question, a stable ecosystem does not exist between lichens, wheat, and cows alone. Cows need grass, and grass needs a whole host of soil fungi (mycorrhizal fungi) and symbiotic bacteria to gain anything from the soil, decomposers are also required to break down the dead grass and bones and such of cows. It is also important to note that mars is a planet. That means that is does not consist of one uniform ecosystem. I dont know about everyone else here but I am not aware of any cows farms on antarctica. And the grasses that grow in different climates are completely different and also degrade the soil in varying amounts. Other organisms are also pivotal to fixing nitrogen from the atmosphere and conducting pollination, cycling other nutrients, changing atmospheric composition etc. So in short, we would definitely need more than one or two organisms to form a stable ecosystem (a key word because it means literally the interactions between lifeforms). Insects help keep other bugs, plants etc. in check and you have to have different species of grass and the like in case a blight comes through and kills all of one type of grass- insects are necessary to make sure that certain types of those plants don't take over and kill off the others, and even animals are necessary to keep those bugs in check. [Answer] ## Genetically modified grass. Not your average tall fescue, but grass modified with genes that will allow it to survive on Mars. Anti-freeze genes, uv protectant genes and the like. Hopefully it will be edible, and tasty, too! Because, once you get there and kneel down to kiss Martius firmus, you might be just a tad peckish from months of shipboard fodder. I literally just turned off the tele (Science Channel) and they were describing experiments with plants actually being grown in a Mars like atmosphere. ]
[Question] [ Acording to current scientific knowledge, birds descend from theropod dinosaurs. This evolution had, as usual, some transitional forms, like [Archaeopteryx](https://en.wikipedia.org/wiki/Archaeopteryx). Following this evolutionary path, we notice that the birds lost their teeth in favor of a beak. But, from my research, it is not entirely known how birds lost their teeth. And even though some scientists mention that Archaeopteryx had a sort of beak, I don't think its skull is much diferent than, say a Velociraptor of sorts (that's my uninformed, layman opinion). [![Archaeopteryx skull](https://i.stack.imgur.com/wKYUl.jpg)](https://i.stack.imgur.com/wKYUl.jpg) For my world, I would like to have some kind of reverse evolution, where a bird of prey develops some dinosaur-like properties. I am not interested in detailing on my book the evolutionary pressures that would lead to this, so feel free to extrapolate acording to what will make your answers more plausible or easy to respond. What I am interested in... is that this transitional form is fully functional (otherwise, it would go extinct) and that it would have a beak and teeth simultaneously (so as to illustrate where it came from and where it is going to). As I said, the Archaeopteryx model doesn't seem to highlight the beak thing too much... I would lean more on the Triceratops model, but alas, that was a herbivore, not a carnivorous species (as I would like it to be). [![Triceratops skull](https://i.stack.imgur.com/uugCj.jpg)](https://i.stack.imgur.com/uugCj.jpg) So, my question is: how would this creature's skull be? Should I go with the Archaeopteryx model, since it has been tried and aparently been successful for some million years? Is there a way to have a carnivorous Triceratops model? Or could you guys figure out another alternative? [Answer] Birds are dinosaurs, specifically they are [maniraptoran](https://en.wikipedia.org/wiki/Maniraptora) coelurosaurs, more specifically [eumaniraptorans](https://en.wikipedia.org/wiki/Paraves)--just like *[Velociraptor](https://en.wikipedia.org/wiki/Velociraptor)*. For an indication of how the jaws of toothed birds would look like see *[Ichtyornis](https://en.wikipedia.org/wiki/Ichthyornis)* and *[Hesperornithes](https://en.wikipedia.org/wiki/Hesperornithes)*, true birds ([Avialae](https://en.wikipedia.org/wiki/Avialae)) which lived in the Mesozoic and had functional teeth. (Modern birds have the [genes for making teeth](https://www.scientificamerican.com/article/mutant-chicken-grows-alli/), they just don't [express them](http://www.bbc.com/earth/story/20150512-bird-grows-face-of-dinosaur).) [Answer] There are several oviraptoridae with teeth. Keep in mind birds don't chew they swallow and let the gizzard do the processing. The oviraptors have a few spiky teeth in addition to the beak. there are also Hypsilophodonts with a beak on the upper jaw and teeth on the lower in addition to chewing teeth. [Answer] There is a dino-guy who's doing something along this line... well, specifically he wants to create a dinosaur from a chicken but thats not the point. The genes to create teeth in birds still exists, it's just not turned on (in fact the dino-guy managed to create a bird embryo with teeth but due to ethics he had to terminate it). Therefore there would not necessarily be obvious 'transitional' forms as such. It could just be that a species of bird is born with teeth, and they're not harmful to the organism. That bird would then go onto reproduce, which would allow an entire population to be born with teeth. If the teeth become useful they they'll become widespread and permanent. I'm not sure if this is useful or not but thats my knowledge on the situation. [Answer] I would expect it to develop initially in fish-eating sea birds or waterfowl. Simple teeth are quite useful for holding on to slippery fish. In fact, this has already happened. Ducks and geese do not have true teeth, but they do have serrated surfaces on their bills that serve the same function. And penguins do not have visible teeth on their beaks, but they do have them on their tongue. And the roof of their mouth. And the inside of their throat. Most birds that would have a use for teeth find an alternative because teeth are heavy and flying is important for birds. But a flightless water bird that did not opt for the Sarlacc pit solution of the penguin's ancestors might plausibly revert to a dinosaur-like form. [Answer] Some birds started to evolve teeth-like structures, check geese, toucans with saw-like beak extensions, and there is also a species of hummingbird with spikes on beak that looks like teeth. Evolution never goes backward, so instead of growing their ancestor's teeth, birds could invent "teeth" again. [Answer] Some carnivorous birds already did this. It's most obvious in pelagornithids, also known as pseudotooth birds. In addition to being among the largest birds ever to fly, they had false teeth which were actually outgrowths of the jawbones. ![enter image description here](https://i.stack.imgur.com/X8phc.png) Raptors also have something similar, albeit in a much more subtle form. Tomial teeth are sharp little projections found in the beaks of birds of prey, and also a couple of other groups like shrikes and butcher birds. They assist in killing prey. ![enter image description here](https://lafeber.com/vet/wp-content/uploads/falcon-tooth.png) Geese and their relatives have comb like structures in their mouths called pectens; these can be quite terrifying. In flamingoes, they have been modified into filter feeding organs, kind of like the baleen of mysticete cetaceans. ![enter image description here](https://i.stack.imgur.com/uNMTz.jpg) Penguin mouths are quite horrifying, not least because of their awful tongues. Yes, their tongues are covered in large tooth-liked spikes, known as lingual papillae, which presumably help them munch fish. ![enter image description here](https://i.stack.imgur.com/jO30c.jpg) Speaking of papillae, a lot of birds also have these things called choanal papillae, which are backward facing spines which are found deep inside the mouth, around what's known as the choanal slit. ![enter image description here](https://i.stack.imgur.com/GdbDs.jpg) I think that all of these qualify for your hypothetical transitional species with both a beak and teeth. As often happens with these questions, it seems that nature did it first. ]
[Question] [ A man with a past traumatic experience developed dissociates amnesia. Every time he experiences something traumatic, his id persona hiding in his unconscious mind comes out taking over his body. This persona causes the man to transform into a powerful and unrecognizable being. His hair, eyes and his clothes completely change. How? When the man wakes up to his normal self, his case of amnesia kicks in without knowing his secret ability. When he's traumatized again, the id persona kicks in and transforms in an instant. Id: The Id is the unconscious that is impulsive, a child-like behavior of the psyche that is connected with the pleasure principle, an instinctive drive to seek pleasure and avoid pain. It is expressed as a basic motivation force that reduces psychic tension. It is the force of our needs, desires, impulses, and particularly our sexual or aggressive drives. It is the dark inaccessible part of our personality it knows no values, judgments, good vs. evil, or no morality. You can read up on the id, ego, and super-ego by Sigmund Freud if you want more information on it. [Answer] ## Human Variant This answer does not apply to humans with their current genetic makeup, but rather to an alternate version of humans that has extremely intricate control of all parts of it's body shape via muscular hydrostats and also control of body color via chromatophores. Perhaps mutation or genetic engineering could give rise to humans with these physiological systems. ## Muscular Hydrostats For Shape Shifting [Muscular hydrostats](https://en.wikipedia.org/wiki/Muscular_hydrostat) are the mechanisms [enabling octopuses to quickly alter the shape of their bodies in incredible detail](https://blogs.scientificamerican.com/octopus-chronicles/how-the-octopus-creates-instant-3-d-camouflage-on-its-skin/). An example of the extreme shape shifting control that muscular hydrostats provide is seen [here in this video](https://youtu.be/JSq8nghQZqA). ## Chromatophore Layers For Color Changes [Chromatophores](https://en.wikipedia.org/wiki/Chromatophore) are pigment-containing and light-reflecting cells, or groups of cells, that allow animals such as the cuttlefish, squid and octopuses to rapidly change color through mechanisms that translocate pigment and reorient reflective plates within chromatophores. This process, often used as a type of camouflage, is called physiological color change or metachrosis. The amazing speed and complexity of chromatophore color changes can be seen [here in this video](https://www.youtube.com/watch?v=l1T4ZgkCuiM). ## Shape Shifting and Color Change Clothing [Academic scientists and also the US military are researching](http://www.isciencetimes.com/articles/6758/20140129/cuttlefish-change-color-chameleon-sea-military-camouflage.htm) the shape shifting and camouflaging abilities of cephalopods in an attempt to make clothing capable of transforming on command. [Mind-machine connection](http://newatlas.com/implanted-electrodes-paralyzed/46593/) is now possible and will likely become more common and less invasive. ## All Together When taken all together, all these existing abilities and technologies could give rise to a trans-human capable of completely transforming his physical appearance and even his clothing in an instant. [Answer] # Pseudoscience is the norm from here on out There is no 100% "scientific" way to transform a person and their clothes in an instant because they experience trauma. There are [conditions](http://www.webmd.com/mental-health/dissociative-identity-disorder-multiple-personality-disorder) that could cause the distinct personalities, and it's reasonable to think that a change in personality could release the hormones needed to tell the brain to change the body. The **trigger** is realistic, but the actual of change is ... difficult to explain. ## Cheating * **Advanced creatures** are employing this man to provide the changes they want to see, so they have implemented the mechanisms to make his changes happen. They are beyond our grasp, but we can observe what happens. * **There are laws and forces at work that we don't understand**. Science doesn't decide the forces that make the world work, it just explains them. Therefore, you can handwave forces that apply to this man because of his unique characteristics and the best we can do is explain what we see. * **Physics that scientists do understand work differently in your world**. You could conceivably rewrite the physics of this world so that this sort of change is well-understood. It's just simply due to the *Law of (LawNameHere)*. Another name for this is **magic**. ## Less cheating * **Paranormal "science"** which some claim is "proven" to be real turns out to be accurate. This doesn't necessarily have to involve human "ghosts" - humans don't need to have an afterlife or anything like that - but it implies that there are metaphysical processes we don't understand. Metaphysical intervention (which some theorize is possible) could do the job for you. ## Hopefully not cheating * Humans have **dormant and repressed genes**. Some are activated when they're needed, while [others](https://en.wikipedia.org/wiki/Atavism) may emerge rarely at birth or via mutation. Your character could have a mechanism that expresses dormant genes to respond to trauma, just as these changes can occur in everyday life to respond to stimuli. These genes could "change" the character and potentially do something with their clothes too (?). This idea is explored in the *Doctor Who* episode [The Lazarus Experiment](https://en.wikipedia.org/wiki/The_Lazarus_Experiment), in which a scientist cycles from human to monster and back multiple times due to a failed gene treatment. * **This character could have a unique morphology** that includes a subdermal "being" layer. His skin and clothes would tear, rather violently, off of his body, revealing the form underneath; then that layer would tear off hours later, revealing another humanoid layer. This is difficult to explain biologically (genetic modification via a virus, perhaps?) but it's interesting nonetheless. A somewhat recent TV show with a werewolf (not sure what it was called) explored this idea. * **Quantum mechanics** swap out the bodies but preserve most of the mind. [Entangled](https://en.wikipedia.org/wiki/Quantum_entanglement) particles could link the tissues, and [tunneling](https://en.wikipedia.org/wiki/Quantum_tunnelling) could explain how things move. [Superposition](http://www.physics.org/article-questions.asp?id=124) is also essential for any explanation that involves switching things out. [Answer] I have a feeling that this is just a variation of the "by magic" answer proposed by kingledion with just a bit of "scientific snake oil", but here it goes... ## Parallel universes The man has a psychic connection with his own self in a different universe. Only that in such universe, his version1 of itself has superpowers2 (and of course, he dresses using what is normal in his world). When stressed, the adrenaline activates certain cells of the man's brain, causing them to create an electric current. That electric current estimulates the quantum entanglement, bringing the body of the "superhero self" to this universe through the wormhole. You can decide if the man's cerebral activity (his identity) stays in the newcomer's body of it that is replaced, too. As you see, all perfectly rational and scientific. --- 1Or maybe in his Universe everybody on Earth has what we would call superpowers. 2How two beings so different have become the same individual is a philosophical one. Maybe it is because of magic. Or better, *quantum entanglement* due to the effect of a wormhole. [Answer] ## **Mood, by Ralph Lauren** You've heard of mood rings. A mad fashion designer (sorry Ralph) creates an ensemble that expresses a persons emotions. Your protagonist, being known to have frightful mood swings, is targeted as a perfect guinea pig. Might be the fashion designer even found a way to cause these wild mood swings just to see the impact they would have on the design. Sure the results are extreme. Even the hair and eyes! But fashion loves to push the boundaries to see what new normals it can create. If your Jekyll and Hyde is going to play both the hero and the villain he might as well look good doing it. ]
[Question] [ Could anyone could survive a nuclear war and all that follows? I have read many things saying they would, and read other science-based answers, but they all talked about a nuclear war that was relatively small (100 nukes fired between India and Pakistan). Would anyone survive a nuclear war of NATO vs. China and Russia, or something similar, where all the nuclear bombs they could fire were launched? I have read people would be better off in the Southern hemisphere, but how would they be, and how many people would survive? [Answer] > > I've been looking at other answers, but I'd like to know, science > based, if anyone could survive a nuclear war and all that follows. > > > Could anyone survive? Yes. Across the United States there are a [variety of fallout shelters](http://library.uoregon.edu/ec/e-asia/read/familyfallout.pdf). Some are public, most are [private](http://www.hardenedstructures.com/bunkers-for-Sale.php). A few are for [government use](http://www.npr.org/2011/03/26/134379296/the-secret-bunker-congress-never-used) and hence, not publicized. Add to that, fallout shelters in other countries, like [Canada](https://en.wikipedia.org/wiki/Emergency_Government_Headquarters). So, assuming people get to the existing shelters and they are not in the blast radius of a weapon, yes, **some** people could survive a nuclear war. How long they survive after the blast depends on the amount of supplies they have. > > I've read many things saying they would, and read other science-based > answers, but they all talked about a nuclear war that was relatively > small (100 nukes fired between Israel and Palestine). Would anyone > survive a nuclear war of NATO vs. China and Russia, or something > similar, where all the nuclear bombs they could fire were launched? > > > There are estimated to be over [15,000](http://www.ploughshares.org/world-nuclear-stockpile-report) nuclear weapons held by the nine countries known to have such weapons. About 2,000 of those are on a "High Alert Status" meaning they are already programed with a target and could be deployed (launched) in minutes. Russia and the U.S. account for about [14,000](http://www.icanw.org/the-facts/nuclear-arsenals/) weapons and about 1,800 of the "High Alert Status" weapons. So, let us say all 2,000 that are on "hair triggers" are fired. While we don't know the exact yield, a fair estimate for a modern weapon would [1 megaton](http://military.wikia.com/wiki/Nuclear_weapon_yield) each. [Due to the wide range of devices and delivery systems, setting an average is not simple.](https://en.wikipedia.org/wiki/Comparison_of_ICBMs) Each five megatonnes of explosive power translates to about one ton of mass for the weapon. A 1 megaton device would clock in under a quarter ton. That is a good size, but manageable for several delivery systems, both short and long range. While we have tested much larger yielding devices [(15MT, 25MT, 50MT)](https://en.wikipedia.org/wiki/List_of_nuclear_weapons_tests), smaller is more practical. Also, as a device's yield grows, its destructive ability only matches that growth to a point. The reason is the earth's atmosphere. It is the pressure of the atmosphere that spreads out a blast. As you go higher, the pressure of the atmosphere is less. This affects the nuclear blast in that it, like any wave force, will follow the path of least resistance. So, as the power of the blast increases, the area of planet's surface affect will not increase in proportion because the lower density of the upper atmosphere, having less resistance than atmosphere near the ground, directs the blast upward more than outward. Indeed, the difference between 50 and 100 megatonnes at ground level would be very small because, even with twice the power, the 100 megaton blast would lose most of its power from the escape of energy to space as it would blast all the way out of our atmosphere. At least that's the theory based on the [biggest test ever](http://military.wikia.com/wiki/Tsar_Bomba). Assuming 1 megaton each, that means a total force for all 2,000 would be 2,000 megatonnes (2 BILLION tonnes of TNT). [That's enough force to throw millions of tonnes of debris high into the atmosphere.](https://en.wikipedia.org/wiki/Nuclear_weapon_design) Add to that all the ash and smoke from the fires caused by weapon detonations, easily adding millions more tonnes of radioactive material in the air. These particulates blocking sunlight, and the fact that they are a radioactive, is what gives us the term "[nuclear winter](https://en.wikipedia.org/wiki/Nuclear_winter)". That debris would remain in the atmosphere until it settled back to the ground. Rain would be the biggest player in that process. Wind and rain would carry this radioactive [fallout](https://en.wikipedia.org/wiki/Nuclear_fallout) across much of the planet's surface. No one knows, for sure, how long it would take that much matter to rain back to earth, but a few years is easily possible. During that time, sunlight reaching the surface would be reduced. This would affect the earth's ecosystems, as plants die or are reduced in number, the higher organisms would suffer as well. On top of that, it would be colder with less sunlight. Of course the air clearing is both curse and blessing. While clearing air means more sunlight and heat it also means that some areas get hit by the radioactive rain. Such places will be contaminated by fallout for many years, anyone in these areas will most likely die, some faster than others. > > I've read things would be better off in the Southern hemisphere, but > how would they be, and how many people would survive? > > > This is due to the fact that most targets for nuclear attacks are in the northern hemisphere, hence, that's where the firestorms and ash clouds will originate. Weather patterns between the north and south are such that most of the airborne ash will remain north of the equator. That's, in part, due to the sun's effect on air near the equator, it's hotter there so more air is pulled in from the colder areas near the ground and, likewise, expelled toward the colder areas at higher elevations. While this [air current](http://oceanservice.noaa.gov/education/kits/currents/05currents1.html) wouldn't stop ash traveling to the southern hemisphere, it would reduce it. That translates into less radiation delivered via fallout and more sunlight reaching plants in the southern hemisphere. Both of these factors will mean the survival rate in the southern hemisphere will be greater than that of the northern hemisphere. In all likelihood, the much greater. [Answer] To be honest, no one really knows. There are plenty of people who've modelled nuclear winters, and they've come up with answers ranging from 'very little happens' to 'pretty much all life on the planet is doomed'. So to some extent, just pick whatever fits your narrative and go with it, there's as much chance of its being right as any other prediction. [Answer] Yes the southern hemisphere will fair much better than the northern, there are no nuclear states in the southern hemisphere so there are fewer targets. the continents are widely spaced reducing secondary fallout. Fallout and ash will only slowly cross the equator due to the air flow patterns, and will not make it to antarctica at all for the same reasons. Generally rural areas with low populations far from cities will fare the best. isolated water systems (like the salt lake system) will help reduce contamination, the smaller the better. Aside from the political and economic effects, (which admittedly would be huge) the southern hemisphere is not going to be hit as hard. here are two detailed projections of the effects. [1](http://www.johnstonsarchive.net/nuclear/nuclearwar1.html) [2](http://www.nucleardarkness.org/warconsequences/hundredfiftytonessmoke/) [Answer] The general consensus by most governments is 3 weeks for fallout to clear. it doesn't matter how many or how big the bombs are, the decay rate is still the same. HOW MUCH that is released is determined by size of warhead and how far off the ground it was detonated. However, that being said, in a full scale nuclear war, how much of the planet would be covered in clouds is up for debate. However DoD has estimated that at least 106 million would die from the blasts and radiation (for those that aren't in a shelter or don't have one) so that is nearly 50% of the US. There would be food and water shortages so there will be starvation of course. Then there are those who would be killed in looting in areas that weren't hit and by marauders (yes, those would really become a thing). Then there would also be disease. *I* estimate that the nuclear blasts and rads alone would kill at least 48% of the world population and the mayhem after that to be to probably kill another 10-20%. This would include starving people and those got by the wolves while they're still undecided and not fully realizing the situation. So, approx 32% of the world population would still be alive by the time some sort of order is restored, but that is my guesstimation, and not based on anything official, so take it how you will. ]
[Question] [ Someone invents a portable, incredibly high-powered laser or similar energy weapon. The mechanism of energy production can be hand-waved away. In other words, it will heat up. Lots. Gigawatts lots, or terawatts/petawatts/etc. Handwave any production rate you like into this. *Using only substances that exist in our real world, what is the practical limit on how quickly a **portable** energy weapon could be cooled-down? In other words, **what is the maximum sustainable energy output** of such a weapon, assuming cooling rather than energy production is the limiting factor?* The sort of thing I'm thinking of: Suppose you had a larger device nearby (on a truck, say) which could cool down helium to a liquid and pump it into your energy gun via a tube. The liquid helium would have to be pumped around *quickly* to prevent it from boiling. For sufficiently high weapon wattage, the sheer volume of helium needed, and the size of the cooling apparatus, would exceed what you can put on an accompanying truck. I suspect substances other than helium will have a better heat capacity before boiling, or a better rate of heat transfer, or some other property, but you get the idea. Other than the internal mechanism of the weapon, there is no significant advance in materials or other technology beyond what we have here today. [Answer] Let's imagine that the hottest part of the apparatus is the barrel, so to speak, which is cylindrical with length $l$, radius $r$ and temperature $T\_b$. We can surround it with a fluid of temperature $T\_f$. Now, the barrel has a [*heat transfer coefficient*](https://en.wikipedia.org/wiki/Heat_transfer_coefficient) of $h$. The change in heat energy of the barrel over time, $\dot{Q}$, is $$\dot{Q}=hA\Delta T=h(2\pi rl)\left(T\_b-T\_f\right)$$ where $A$ is the surface area of the barrel. Some things immediately spring out: * A greater heat transfer coefficient leads to quicker cooling. * A larger area over which to transfer the heat leads to quicker cooling. * A greater temperature difference leads to quicker cooling. $h$ depends strongly on the properties of the materials, which can be hard. We can make some estimates for the other quantities, though. * The source is portable (which I'm taking to imply that it could fit in a large van, for instance), so I'll estimate that $l=3\text{ m}$ and $r=0.05\text{ m}$ (perhaps the latter is a bit large). This leads to $A=0.942\text{ m}^2$. * Let's be extremely generous and say that the laser reaches temperatures of about $T\_b=1,000\text{ K}$. This is really stretching it. At any rate, even if $T\_f$ is close to $0\text{ K}$, the difference $\Delta T$ cannot be greater than $1,000\text{ K}$. Therefore, let $\Delta T\sim1,000\text{ K}$. The best [transfer coefficients](http://www.engineeringtoolbox.com/overall-heat-transfer-coefficients-d_284.html) I can find are actually water-to-water. However, air-to-steam can yield an $h=17\text{ W m}^{-2}\text{ K}^{-1}$ through copper (which has a melting point higher than the temperatures involved here). We therefore have $$\dot{Q}\sim\left(17\text{ W m}^{-2}\text{ K}^{-1}\right)\left(0.942\text{ m}^2\right)\left(1,000\text{ K}\right)\sim16,000\text{ Watts}$$ That's pretty nice . . . if the temperatures (and temperature difference, for that matter) don't cause the entire weapon to fall apart. [Answer] As far as I know, the record for watercooled heatsinks goes to... actually several different designs (search "heatsink water MW/m2"), there are several papers on heatsinks that can handle 20+ Megawatts/m2 (that's surface of the sun levels). I remember seeing a design capable of 40MW/m2, basically a Tungsten or Molybdenum plate with a tight bunch of supersonic water jets being blasted at it (the trick is to move the water fast enough and with enough force that it doesn't boil). But your real problem is the thermal conductivity of the device itself, diamond being the best confirmed thermal conductor at ~2000W/m\*K or 2kW/m2 of heat down a 1m long block would result in a 1'K (1'C) temperature difference. The solution? Make said laser very flat and long, thin and high in surface area is the way to get really good cooling. But the true record holder for *most powerful heatsink ever* goes to the precooler stage of the SABRE hybrid rocket engine where they claim "The experimental device achieved heat exchange of almost 1 GW/m3", but seeing as it used liquid hydrogen, you could fire off your multi-gigawatt laser device for as long as your supply of liquid hydrogen held up, then you'd have to wait while you condensed some more. Of course the *real* limit will be the devices efficiency. If your device is 90% efficient (and some lab-grade lights are getting pretty close to that now) then you can pump out ~10GW *continuously* per m3 of device until you run out of coolant. As a side note, I do remember seeing a paper on a carbon nanotube capacitor with a power density of a couple of Megawatts/liter (or a couple of GW/m3) but I can't seem to find the page. (aluminium foil caps can produce even more power, but their energy density is terrible in comparison, by like several orders of magnitude) So the upper limit for current technology both in heatsinking and in power sources seems to be around the Gigawatt/m3 mark. Solution? Switch out your van for a big rig, a 40' container for the laser, another 40' for the cooling and a final 40' for the power supply and you've probably got a Terawatt class device that could run for some appreciable fraction of a second (and a large road train too) [Answer] ## Avoid Excessive Heating of the Weapon This is sort of not what your are asking, but it is a way to avoid having to cool your weapon--namely do not overheat the weapon in the first place. One way to achieve this is to have your energy projecting sources seperated from each other enough that any one emitter is easily cooled. Then have each of the beams meet at the target, uniting into one beam with constructive interference. If you want to, you can incorporate bounce stations/vehicles so that your beams can be generated from many different places and be reflected accordingly to the convergence point with mobile aircraft, satellites, ground vehicles, etc. If you carry this idea out far enough, you can have enormous power plants stationed around the globe or solar system, either mobile or not, and have a network of bounce stations capable of dividing the beams so that certain percentages can be sent simultaineously to many recipients, i.e. powering many handheld guns, mobile vehicles, airships, destroyers, nanodrones, etc. all at the same time. [Answer] We have to take newtons law of cooling into consideration here, Newton's law of cooling states that the rate of heat loss of a body is proportional to the difference in temperatures between the body and its surroundings. As such, it is equivalent to a statement that the heat transfer coefficient, which mediates between heat losses and temperature differences, is a constant. we can go for something cold like liquid nitrogen and give your weapon Liquid cooling system but it will work fine only if your weapon does not fall apart by it's own heat. [Answer] Hand-waving away the energy generating part renders this question not very effective. Efficiency is of paramount importance. If the process is ideal, 100% of energy is converted into the laser beam. Then you don't have a heat transfer problem. The most efficient lasers today can convert about 70% of electricity into light. For any amount of heat generated one can build big enough of a heat exchanger, to have enough surface area, with millions of heat sink fins, given a bit of temperature differential, to conduct all the heat away. Therefore I can say there is no limit based on the constrains provided. In practice there is always constrains, such as size, weight, cost, etc. Therefore in the real world the real answers to real problems are found in balancing all the constrains. ]
[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/62439/edit). Closed 7 years ago. [Improve this question](/posts/62439/edit) People (maybe even you) are running obstacles very often when it comes to worldbuilding. The internet is full of worldbuilding question lists to help it: factions, people, magic, tech and so on. There are several different question sheets, for different purposes, and be honest: with different quality. Some of these sheets involve questions even about the favorite color of the clothing of the character's pet, or the exact amount of salt in the celebrational dinner of a city in a country. On Reddit (/r/worldbuilding), I've noticed that people tend to skip certain questions, either absolutely, or for a small amount of time. I'd like to avoid it and concentrate only on the matter. Can you provide key questions that **usually** cannot be skipped? I think of ones like: * character: name, gender, age, race, skin color, hair color, place of born... * factions: name, form of government, age, major cultural traits, current wars, wealth, state religion... * magic: basic means of usage, limits, time to learn, time to master, what prevents from destroying the world with it... These are *very loose* examples, to get the idea. Also, I know this question is possibly too broad, so I'm asking only about *the most fundamental* things, that are equally important in a D&D game and in a novel - if there's any such question. If there isn't, then only one purpose is enough. [Answer] I think that the direct answer to this question varies greatly from story to story. If you're writing a story of medieval political intrigue, the governing styles and religions are utterly indispensable. However, if you're writing a story about two lovers destined to meet, those may be completely unimportant. Instead daily life of the individuals may matter. One approach I would use to build your own answer to this question is to pick one "hard edged" question to answer and one "soft" question to answer. Your hard question would be the one which creates the sharp defining edges of your story. For the story of political intrigue, the exact governmental structure might be your "hard edged" question. It lets you know what can and cannot be done in your world, providing bounds the reader can rely on. The "soft" question is the one you pick to define the more broad brush-strokes that paint a picture of your world. These questions rarely lead to concrete use cases. Instead they tend to vaguely shape the path forward. That same story of political intrigue might have its "soft" side formulated around religion. Perhaps the story might be set in a time where the freedom of women is increasing due to a religious pressure. Having both a soft and a hard question lends dynamic range to the world. You need the soft questions because, frankly, it's insanely time consuming to pin down every aspect of the world with crisp clean edges. You need the hard questions because readers want to see life in your story, and it's hard to see life when everything is muted and soft. Your main character cannot challenge the slow movements of the soft religious overtones, but they may seek to undermine the existing hegemony of a particular royal family. [Answer] This answer focuses on fiction. The most critical worldbuilding questions for fiction are threefold. The broadest questions are about the overall architecture of the world itself. If it's set in a secondary creation type of world as found in most High Fantasy trilogies, this provides a geographical and historical context and what the anthropologists call 'cosmological' factors like the nature of magic, whether the gods are real, and the biology and ecology of dragons. These questions form the shape of its universe. The most close-up questions are about the characters and the story that affects them. Who are these characters? What is their role in this world? What are their goals? How are their goals in direct conflict with the problems the story will throw at them? Between the broadest and the most close-up levels is the intermediate set of questions. They are the connective tissue of a story, drawing together the characters and their world as a whole. These questions focus on the coherence of the world and its relationship to the story as its setting. Is the advertising executive who found himself in Lower Earth really the stepbrother of the newly risen Dark Lord? Why do giant alien cyborg spiders want to capture a thermostellar physicist and steal research into neutrino refraction? This concentrates on the problems they face and have to deal with in resolving their story. They show how the characters can and must handle their problems. What are their limitations. What complications must inevitably arise in the course of the story. The answers to these questions shape the storyline. In the narrowest sense, in fiction the world exists to drive the story, to give substance the reality of its characters, the events they encounter, and give a sense there is more to this place where the story happens than a few scenery flats. That there can be a world beyond the confines of a story, with its own sense of reality, where more can happen, and that effort and imagination has been expended to give its own distinct poetry. [Answer] When world building I find the most valuable questions to all be about the forces driving everything that happens. What is the economy of your civilizations? What do your people eat? How do they get energy, tools, clothing, housing, and transportation? Where does their waste go? Worlds feel really contrived and false when a city has no way to feed itself or when a village exists in some dramatic location for no practical reason. If there are rulers, what governs the flow of power in your world? How does one become and stay a ruler? What prevents someone else from usurping the ruler? If you are inventing a species of animal, what does it eat? How does it reproduce? Bad world building results in predators who roar while hunting and who outnumber their prey. ]
[Question] [ In a story a long time ago in an age long forgotten, the main characters find an ancient portal-gate-system, powered by an even more forgotten magic. The main characters have access to soldiers, within a reasonable limit, within a fantasy / medieval setting. How would our characters proceed with the exploration? * Magic is not gone but generally forgotten. So no scrying spells. * Matter only appears on the other side as soon as everything has been de-materialized, so no poking a stick through. * The gateway is roughly "stargate size", so a horse mounted warrior can ride through it. A rhino or elephant rider cannot. * None of the other gates are off-world.  They are either in the same world / continent, or destroyed. * If the receiver gate is gone, the sender gate "connects" but the transmitted matter ends up everywhere as scattered matter (on atomic level?). * If the receiver gate is covered, inside the earth, debris, the sender gate connects but the transmitted matter is fused with whatever is on the other side (or perhaps scattered somewhat evenly between the gates). Each portal is a physical gate, appearing inside a gate room, with no possible way to move it without breaking it (it is old). [Answer] In the cultural context you describe, this would be handled much like a [forlorn hope](https://en.wikipedia.org/wiki/Forlorn_hope) party. A small group would volunteer, against the promise of rich rewards if they survive, or a group of criminals would be offered a pardon if they survived. They'd go through and try to return immediately with a report of the conditions on the other side. If none of them came back, you'd try another route. If any come back, they are carefully questioned about conditions, and an appropriate party is formed and equipped for the mission. The forlorn hope survivors are kept from leaving, politely but definitely, until it's clear that their report was actually accurate. If it wasn't, the penalties would be medieval. [Answer] Expanding on [John Dallman's answer](//worldbuilding.stackexchange.com/a/56626), there would be several phases to this. Discovery – Where the network is first found and efforts are made to understand what the portals do and how they work. How this unfolds will largely be driven by the personalities of the people who found it. Securing – Inevitably, access to a nearly instantaneous, long-distance form of travel would be economically invaluable, especially if it is highly reliable with securing and maintaining the portal sites. Fortifications would likely be set up around known portal sites by whatever social power got to it first, and if civilians are allowed to use it (for a modest fee of course), local communities would spring up around the portal sites. These cities would become major trade locations and points of enormous economical power. The ability to instantly move troops (particularly highly trained special ops tasks forces in this case) would also make these sites highly valuable military assets as well. Long Term – Depending on whether the securing phase went on a economic, military, or hybrid route would affect how things develop here. Economy – With an economic focus, people would flood to these gate locations. More people means more expansion, and more and more efforts will be made to expand the local cities and explore the surrounding areas for useful resources. Paths would also be made to make it easier to get to these locations. Aside from the rapid transport of supplies, the fact that the portals are pre-made and unmovable would limit major exploration to the areas around existing portals (but the portals can grant access to lands/areas too dangerous to reach/explore otherwise). Military – The ability to move troops and supplies great distances quickly would mean that the first group with expansion power to get their hands on one of these portals would quickly be able to gain footholds everywhere there is a portal. With lots of small colonies, they would be able to expand their empire faster than anyone else, and be able to defend larger areas with fewer troops. More territory will also mean more resources, making this faction economically well off. And unless there are large areas the portals don't connect to for a resistance to hold onto, the portal faction will likely become a superpower, overwhelming all opposition with their accumulated wealth/overwhelming numbers. The above assumes that the gate is perfectly safe if you secure and maintain both sides of the gate. If there is even a 0.5% chance of failure (randomly disintegrating what it transports, because it's old), this would kill the military aspect as the failure rate would become a "portal tax", and repeated use by an army would decimate it. [Answer] Continuing from Tezra's answer which continued from John Dallman's answer. Your empire could set up a portal messenger service once established connections with other portals had been found. The ability to quickly inform different cities/parties about a raid/invasion in another area of the empire would allow for quicker reaction times. If the enemy was unaware of these portals they would be surprised when their surprise invasion didn't yield the expected results. The empire with the portals could either meet them on the field with a well prepared army or send some special ops teams with fast horses to delay them with guerilla tactics while the main army is called up/deployed. If the enemy is aware of the portals, aside from trying to take control of a portal city, they could actually take advantage of the empires 'tech'. They could make a show of preparing to attack/invade from one location. This information is then sent to the empires central command via portal messenger and they make the associated defensive countermeasure.. Only to find that the main invasion is coming from somewhere else. Very much like the false information spread to the Germans before D-day in Normandy during WW2. If the enemy does succeed in capturing the portal city they could block off the portal and kill off any reinforcements coming through. Or they could attempt to use the portal themselves to sneak soldiers behind enemy lines to quietly spy/sabotage other portal cities in the network. If the enemy can find a portal that the empire is unaware of and get their hands on the dial up sequence for the empires gates...surprise raiding parties inside the empires strongholds! Etc etc it goes on and on. With the danger of never knowing when a gate had been blocked off, even your own gates, I think a procedure for informing the home portal should be set up. Eg if a group is sent through the gate, no reinforcements should be sent through until one of the first party returns. For established portals where you believe it is safe, there should be a regular check in sending back an all clear message. Either daily or every few hours. It all depends on how much energy your magic portals require and how frequently they can be switched from send and receive. (matter only travels one way?) [Answer] The question is basically "who explores when there is a high likelihood of death?" In the actual medieval period there were plenty of folks with a much more pragmatic approach to death, so simply good pay could get a number of volunteers to go through the portal, recon the other side (if they survive to get there), and report back. Establishing that pay is sent to the family for those that never report back (and presumably die on the other side) is key. Of course unless there are instructions on the portal about the consequences of connecting to a destroyed or blocked portal, I'm not sure how you would know that failure to return could mean a "dead end" gate address or just an inability to return (they can't "dial back", can't reach the return gate because it opens into a pit, are held prisoner, etc). Anyway, the quality of these pseudo-suicidal folks would probably be fairly low, but so long as their mission is just "get to the other side, turn around and come right back" they should suffice. A sufficiently powerful king figure could compel soldiers through, but I think he would either have to conceal the fates of prior missions or demonstrate that most (like 70-80%) of gate addresses lead to a safe destination. In the pre-modern era there were travel perils aplenty, from storms to raids to just getting lost in the wilderness. So a certain level of risk was accepted, but few would go into near certain death unless there was a fundamental compulsion to do so (ie a religious "God has commanded this!!" zealous fervor) or some sort of immediate risk for NOT going (the current place is being destroyed/invaded, so without an escape route everyone is dead anyway). Assuming most portals lead to (immediately) safe places, the usual adventuresome types would gladly explore the other side. Private ventures could fund these missions, contingent on keeping a large share of any profits. The explorers would be gathering exotic animals, plants, and the like, as well as looking for valuable mineral/precious metal deposits. A key member would be a cartographer to map the area and an astronomer (sailor?) to attempt to determine the rough location based on celestial positioning (such as it has been developed in your world). These types of folks are far to precious to risk in the initial portal test however, they would be saved for follow-up explorations. Another option is to first send through some sort of caged or hobbled animal. This obviously won't verify that the portal is clear, but if you wait an hour or so, then send a human test subject, they could immediately verify if the animal is alive. This would confirm that the air at least is breathable, and probably determine if there are aggressive animals in the immediate vicinity. The key objective is to maximize the ability for a person to get in and get out as quickly as possible but still have the most information as possible, since determining that the gate leads to an open portal is the most critical piece of information. Opening up a portal directly into a hostile kingdom that could retaliate would be a major concern. Perhaps the return address, if it has to be inputted at the other end, would be entrusted to just one loyal person (the others perhaps given fake address leading to known dead ends) to ensure it won't easily fall into the hands of unknown aggressors. Obviously the low quality initial test subject would have to know it (and his loyalty to the kingdom may be suspect) but that is a known risk and hopefully he will be in and out so quickly that no one could stop him. If the home gate was found in a condition that would have allowed it to be used (ie it wasn't blocked in some fashion) then it would be a reasonable assumption that NO ONE ELSE is currently using the gate system, so none of the gates probably lead directly to an inhabited area. ]
[Question] [ **In an alternate universe on an alternate earth, we have a nation, or a culture, who with the advent of modern communication technologies has an insatiable thirst for information, be it current events, sports, politics, and whatever else.** **Most humans have been implanted with devices to facilitate a news feed directly into their mind.** Think of it as closing your eyes and seeing the feed from your smart phone. Brain wise this does not function differently than reading the info would normally except that the information can be processed faster. So it’s not as if your brain is being injected with unwanted information it’s just a new delivery method and there is far more information available than any one human could ever hope to process. **The only major variance in the types of information** that can be provided is **a sort of first person video feed**, while not a live stream this medium comes with the ability to record the emotions elicited in the person that viewed whatever is being shared. This evolution has driven reporters and other agents of information sharing to the breaking point when it comes to being able to give stories the proper amount of review and attention. When consumers are consuming knowledge at the speed of thought, being the first to get the information out (and thus pull in ad revenue) is crucial. Even more challenging, **the technology allows anyone to share information with large audiences in real time** though there are no filters/validation steps included, just raw information as the person perceives it or it could just as well be a blatant lie. This information, depending on the content, often makes such waves that formal news agencies are forced to address them as well. **Complicating the situation further** is that the average consumer in this interconnected universe is so inundated with incoming information that rarely are they able to compare the initial source and context of the information to follow up information … *that story is so 4 hours ago* * How do you ensure accuracy of information in such a world. *to clarify, by accurate I mean that a given story/scenario is properly framed. Clearly 100% accuracy is impossible but the problem I am attempting to fix is the idea that there is condemnation and rushes to evaluate before a story is truly told.* * How do you avoid mob mentality when information (be it true or false/true-ish) can be shared peer to peer * How do you protect public figures from a constant barrage of falsehoods and misinformation **Additional notes** these may help you frame your answer. * The nation in question is generally free and democratic and any attempt to reduce that freedom would be opposed by the public, and would reduce to a certain extent the usefulness of an answer. The aim is to fix the problem without significantly curtailing freedoms. That being said if it cannot be fixed but by totalitarian measures that would still be a legit answer. * The nature of the **addiction** is not chemical/physical as it would be with a drug, beyond that the nature of the addiction is nebulous and you may modify it to fit your answer. [Answer] # Attribution, peer review / cross-checking, disentanglement and reputation **Attribution** Digital information can be attributed to a source, through certificates or similar identity mechanisms. With this you know **who** sent the information. **Peer review / Cross-checking** Get the information from more than one angle. Compare the information. Does it appear to correlate? Do others present the same information? If things match up, then the information becomes more trustworthy. **Disentanglement** Do the persons that present the information have any kind of relation to each other? Do they have a stake in the issue? Do they have a quarrel with other casters? This is up to the "news casters" to reveal and they may choose to not do so. But refusal to speak of possible of entanglements automatically lowers the trustworthiness of the information they present. **Reputation** Viewers of the information can rate the information they have gotten and as such the caster gets a reputation score. Someone that has not reported anything before is a faceless nobody and as such does not have any good reputation; their word will be taken lightly. But people that deliver stuff that seems to check out according to the points above will start to earn marks. # ...in other words: just as it is today ...only much faster. [Answer] This isn't an easy question since we're struggling with it on a daily basis. I can list a pretty wide variety of misinformations that have made its way into semi-popular internet culture ('vitamin b17' or the almost montlhy hoax of betty white passing)...It's an inherent risk of the decentralization of information (i.e., anyone can become an information source in today's world). > > How do you ensure accuracy of information in such a world. to clarify, by accurate I mean that a given story/scenario is properly framed. Clearly 100% accuracy is impossible but the idea would be that good information gets to people before they act. > > > I have to say that this is an immediate impossibility as this much of this exists in the interpretation domain. An article on a war has atleast 4 very different frames (one side vs other side vs neutral observer vs arms merchant/profiteer). Which frame is considered 'proper'? (I'm canadian, to me 98% of framing in American news is already framed so very wrong.) Skip war...a proposal to implement gun control, health care, same sex rights, abortion, etc... all have very different interpretation points they can come from. Which one of these view points is 'proper' and how exactly do you determine this and mute the 'improper' ones? It's a weird loop honestly...silencing 'improper' view points is a direct challenge to the freedom of your nation. Attempts to control what is a 'proper' framing of a story will always be a direct challenge to a persons freedom (Yes, freedom involves believing and spreading the belief of the stupidest \*\*\*\* we can come up with, including my answer to your question) Lets ignore the 'opinion' ones and go with factual information only...like reading a university study paper or a medical trial paper. In this case, you need a central, likely peer reviewed, authority to act as the single source for this information. Any disagreeing information out there can be referred to this central source as a point of reference. This central authorities existence won't be easy as it's going to directly conflict with freedom by telling people whats interpretation is the 'proper' framing. > > How do you avoid mob mentality when information (be it true or false/true-ish) can be shared peer to peer > > > This is another one that has been proven that we cannot. Without a significant change to culture and the way we interact, this will never happen. As much as we like to say we are evolved, gathering in groups and throwing virtual stones is how we act. We readily jump on board to group shaming when required (this person was caught doing this on video and it was posted on the internet and 'gasp' oh my, I never...how could they do such a thing!). You avoid the mob mentality on peer to peer once humans social nature has evolved away from it. > > How do you protect public figures from a constant barrage of falsehoods and misinformation > > > Central source of information. If it's not posted on the central source, it isn't true. However, it's been proven time and time again on the internet, if something can be screwed with on the internet, there is going to be a group of people that will. From naming an arctic research ship "boaty mcboatface" (significantly better than other entrees making the top 10 like HMS HitlerWasRight) to sending pop star Taylor Swift to perform a free concert at a school for deaf children, we as an internet community are going to screw with stuff when we see the opportunity. **But I did want to throw out a potential solution for you here. Eliminate internet anonymity.** 1. You now make it publicly known what interpretation point this information is from. You can never guarantee it's accurate, but now it can be traced back to the person who posted it and judgement to its authenticity can be made from there. 2. Mobs are anonymous by nature, eliminate that and you eliminate the safety of being a part of that mob. 3. A few harsh slander laws / misinfo laws and the ability to trace everything back to the originator and this won't be a problem. Of course, this gets back to interpretation and you might have arguements as to whats true and whats not to resolve. Of course in todays world you are going to get one large pushback as the internet community heavily values in anonymous nature and semi-vigilante groups such as anonymous will heavily impede this attempt (anon is hard to deal with as its membership draws from nearly anyone anywhere that wants to be a part of the movement). What happens when anon coordinates a simple DDOS attack on your central sources of info? [Answer] **Ensuring Accuracy** I doubt accuracy can be 100% guaranteed. In this world the news reporters will likely favour speed and a good headline over accuracy. A law could be passed forcing news agencies to have at least two independent sources before they can report. This will improve things a little but it won't stop random people reporting 'news' and having it spread that way. **Protecting public figures** Don't allow anything about a public figure to be posted without two, independent sources. This will help block news agencies from lying about public figures. Track where posts come from and if a post contains lies have extremely strict punishments. Possibly including banning people from posting on the network. This should discourage individuals from lying. [Answer] You fight bad free speech with more speech. Reality is cheap to communicate. Lies take effort. However, things will be validated only so much as people bother to validate them. So when Bob's vacation vids come on line I won't bother to check that Bob didn't really go to Hawaii. He just stood behind some standups of a guy surfing while his wife started broadcasting. A few moments looking closely would tell me the truth. But I don't know the truth. Mostly because I don't care. And that's what's happening today. Politician after politician has to lie to you not because they think you can't find out. It's because they know you don't care. So they tell you what you want to hear. News reporters know the same thing. They only bother with what they know they can get you to read. Why? Well because we all have other stuff to do. [Answer] > > How do you avoid mob mentality when information (be it true or false/true-ish) can be shared peer to peer > > > join 4chan, you will find out over time > > no one cares > > Anonymous do not forget > > > P2P Information is not a problem, liars will lie, those who don't they don't, haters gonna hate, all they will change roles between each other randomly, those who will disagree will disagree, debunkers will debunk, attention whore will draw attention, prophets will prophet, opinions will thrive etc etc. Funny thing is we are used for that longer then internet exists, way much longer. Being used for that is actually one of the reasons for our prosperity (it is, if we compare what we had/was 50000 years ago, and what we have now - there is no doubt). In general what you describe is not different from what we have and what we had. And less you try do it "Right", better it is - peoples will sort that everything out by them self's. > > there is far more information available than any one human could ever hope to process > > > This premise does not mean information will not be sorted out and classified and marked with different hashtags, and labels of your desire. Until you setup White Noise Generator as source of information - most information which people care will be generated by humans themselves. So in general as group they have more then enough power to process it all, and classify it. It is like food, different peoples have different desires in food, but here they will get that information prepared as they it desire and like. Like spicy - you will get, like something else you will get it too. [Answer] I agree with a lot of what is already said, but wanted to add a few things more. When you take into account things like [confirmation bias](https://en.wikipedia.org/wiki/Confirmation_bias), I don't think you'll ever have a case where there is the One True Answer for any problem. Even for instant issues, there are going to be different views and probably some significant polarization on opinions. Because of that, I would expand on the idea of [web of trust](https://en.wikipedia.org/wiki/Web_of_trust) in that the people who believe/agree with a given piece of information is recorded (via a handle or unique identifier). However, I would call this a web of influence (WOI). This would function kind of like Likes or Stars in social network. However, the WOI would let you identify individuals as "I believe in what they say" or "this person is an idiot". Those individual markings would then alter the stars/likes combined based on the perceptions and beliefs of the individual. The other part is that every piece of information that goes through the web allows someone to mark it as +1, 0, -1 (thumbs up/down, whatever). As it goes from the source to the viewer, it accumulates those numbers through relationships and personal opinions. Person0 likes Person1 who likes Person2. Person2 likes a bit of information (+1). Person1 likes Person2's opinion (so +1). So, Person0 sees +2. If Person1 then likes the information themselves, then Person0 would see +3. Likewise, the negative also applies but the value is flipped through a dislike. Negative values are tracked separately. For example, Person0 dislikes Person3 who likes a piece of information (+1) it shows as -1 for Person0. If Person0 dislikes Person3 who dislikes Person2. Then when Person2 likes something, Person0 sees +5 (+3 from above +2 for the 2/3/0 chain). The fun part comes when Person3 likes something. This would show as a +5/-2 (net +3 for general opinions, +5 for personal echo chamber). However, if two opposing sides both think a piece is important (Person2's like in the above example), then it is more likely to be unbiased. So, you could take the delta between the two as the relative truthiness of any piece of information. In this case 7 (+5 -2). If you filtered out less than X for truthiness, I think you'd have a relatively unbiased approach across a large network of viewers. That X could be network/government supplied to reduce mob rule (it only shows up for the bulk of the population once it hits a certain consensus) which would slow down that. There could also be individual filters to change X for specific tags (I want to see cat videos so X is halved); this would also let you address information overload. [Answer] This is an augmented version of what's currently happening with internet reporting today. Most people find a filtered source of news which they trust, supplementing that with the constant barrage coming from unfiltered sources. You say that there is no filtration of the news, but if I know humans (and I am one) then humans would find a way to filter their news in three ways: * For accuracy. * To fit the worldview they already have. * by popularity within their peer groups. Look to the system we already have for your answers, because this is almost the same as what we have. It's actually more likely to be a little more accurate because it's a first person perspective. Those who value accuracy will find as many sources as possible and go to established, trusted sources to get their info. Others will got to Fox News or MSNBC to fit the worldview they already have. The worldview sources will curate these stories to fit their audience's worldview. Social feeds will always have a top story that will be shared virally, and the most popular will be seen more often. **Protections from Slander** We have a difficult time with this in our world. One of the ways this can work is by removing the anonymous aspect of internet interactions. Anyone who doesn't put their name out there can't share in this way (only in a print format). There should also be more stringent and enforced laws, that don't need the individual slighted to come forward. [Answer] What you describe here is like having information delivered only by a huge pack of freelance journalists (terrifying thought, it'd be like having news only from youtubers), that's why with time we built news agencies, and the order of journalist. Side note: this is also in "Deus-Ex Human Revolution", where huge parts of information and news are controlled by a single entity. ]
[Question] [ I'm working on a story that deals with an inordinate leap into the future and was wondering what leaps and bounds in science the human race may have reached by then. So here's what I'm wondering: Over time, we have been able to access information in more and more areas. For example, we're dealing with computation at a quantum level now: a level we previously didn't even know existed. Further, as we evolve it seems we are also getting better at learning more from less information. As we compile information we have learned as a species, and develop new equations for such information, we can extrapolate more from less. Another example: you have a circle with a radius of 1m. What's that circle's circumference? Chances are good you didn't have to rediscover pi. I realize that example's pretty basic, but hopefully it gets the idea across. It seems to me that as we learn more and more about the creation and subsequent events of the universe (which I guess is just all of them), we can start to know about events and matter farther and farther away, both in distance and time. It also seems that if we take this to the extreme (I'm assuming humans make it as a species), we'd know as far away and as far ahead (or back) as possible, making us, for all intents and purposes, omniscient. The only bottleneck I can think of is that pesky Heisenberg's uncertainty principle. Since we can never have complete information about subatomic particles, and they certainly affect the universe, it seems we might run into trouble there. But it also seems like we still might be able to learn enough anyway through everything else that this wouldn't matter. My question is: given this constant advancement of knowledge, could my future humans ever realistically reach the level I'm talking about? We're able to land spacecrafts on asteroids, clearly we can already predict so much about our solar system from it's current state in time. What's to stop us from eventually extending this to the edge of the universe? (I'm not worried about this being a laughably long time from now. I'm just wondering if it's possible.) [Answer] **Maybe** This is a very complex question and depends a lot on the type of universe we live in, and we do not know enough about our universe to answer that. I am also gonna broaden the question to ask can a sentient (infinite processing power and memory) life achieve omniscience. Heisenberg's uncertainty principle would not be a issue, as it doesn't say you cannot determine the momentum and location of object at atomic scale, but rather say momentum and location *cannot* be inferred with certainty in a classical sense, and are probabilistic. Similar to how ideas of length does not matter beyond plank's length, or the idea of *"before"* does not matter prior to Big Bang. Even if we understand all aspects of our reality, a unified scientific theory which describes both micro and macro realities, there could be [Hidden Variables](https://en.wikipedia.org/wiki/Hidden_variable_theory) in the universe which we can never know. We can never know what we cannot interact with (non-FTL), this includes anything outside our universe, beyond observable universe, even objects outside your causality cone. Even if we can predict or mathematically formulate the interactions in this region, it is not the same of direct observable data. But on the other side of things, similar to Quantum entanglement, the whole universe could be in some sort of coherence which makes omniscience possible, but we simply aren't advanced in science enough to know that. P.S. I personally believe that a version of omniscience is possible, and that is the reason for Fermi's Paradox. [Answer] If your definition of omniscience is "to know everything" without breaking the rules of logic and mathematics the answer is NO. It's actually a mathematical problem that is not obvious at all. For example the "halting problem" cannot be solved in finite time. Alan Turing proved in 1936 that a general algorithm to solve the halting problem for all possible program-input pairs cannot exist. <https://en.wikipedia.org/wiki/Halting_problem#Oracle_machines> <https://en.wikipedia.org/wiki/Entscheidungsproblem> <https://en.wikipedia.org/wiki/List_of_undecidable_problems> If you handwave logic and pretend you can be a GOD who lives outside of logic like the Abrahamic GOD then you can just basically say anything you want. BTW omnipotence (the ability to do anything) is also logically impossible. Many philosophers quickly found the paradox which is something like: An omnipotent god should be able to create an object so heavy that even himself cannot lift it. 1) If he can create the object and not lift it, there is one thing he cannot do (lift it) so he is not omnipotent 2) If he cannot create such an object then he is not omnipotent either So an omnipotent entity cannot exist [Answer] No. It is not possible. People said in the 1800s that science had discovered everything but it clearly hasn't. Humans will never know everything. We may be able to learn a lot but there will still be things we do not know. For example we won't know the future as some stuff is determined by quantum which is based in randomness. We will never disprove Gods existence. Proving it is possible if God decides to show himself. Furthermore we will never know if we know everything or what we don't know if we don't know everything. [Answer] It depends on how the universe works: Let's say you want to map the positions of the smallest possible particles that make up our universe. Since there is nothing smaller to "draw" your map on, your map would end up the size of the universe; ergo, we can't know everything at once... ...but we could know anything, provided the universe follows these rules: * No information is ever lost. * All interactions are governed by a very simple set of rules complexity is only a emergent property. * Every particle in the universe has indirectly interacted with any other particle in the universe If those rules hold true, you could beginning with any particle in the universe, deduce the position of any other particle in the universe. This would probably take longer than the heat death of the universe, but at the very least, it's only very improbable not impossible. [Answer] No we couldn't...our brains couldn't handle it sadly. It's possible a future evolution of humans could (Homo Erectus > Homo Sapiens > Homo somethingorother . We would be talking about a large enough leap in our mental capabilities to become a new species at this point. But I wouldn't contest humans becoming omniscient just on a biological level...Omniscience is also a tough definition, especially in morality. What you or I consider right (me : I squished a mosquito!) would be considered horribly wrong from another perspective (mosquito: I was trying to eat and got squished by a giant hand!) or indifference (fly: I'm glad I didn't land there). Is omniscience by definition including knowing all interpretations of one event? Or is it simply knowing something got squished regardless of intepretation? Is it knowledge on the cellular level (the cells of the mosquito now unable to sustain itself) or is it taken from the conceptual mosquito self? It's a hard topic to grasp simply because an observer and their position of observation inherently affects whats being observed. Does omniscience mean knowledge from all observation points, or none at all? The other theory that kinda kinks the omniscient line of thought...All ideas can be disassembled into their components of understanding, but can also be combined with other ideas to create new ones...and those new ones themselves could be combined with others and so on. From this standpoint, there is no 'knowledge of everything' as each new step of knowledge opens the path to yet another new one. And unfortunately, there isn't the 'higgs boson' of idea's...the base idea that inherently exists other pieces of knowledge come from (therefore you can disassemble ideas to infinity in the same way you can combine new ones to infinity.) [Answer] Omniscience is impossible in principle. 1) Knowledge is a codified representation of external reality. By nature, all representations summarize, omit inessential details, and take shortcuts. No representation of reality can contain all of reality; if it did, it would not be a representation but a copy. The map is not the territory. 2) Knowledge depends upon sensation, and as such involves a thermodynamic process. Energy must flow "downhill" from the known object toward the knowing subject. Complete knowledge of every atom in the universe would require the universe reaching absolute zero (and the knowing subject being even colder than that), which simply can't happen. 3) It is a principle of computation that no system can hold a simulation of a system more complex than itself. Complete knowledge of every atom in the universe would require that a brain were able to contain a mental representation of a system that not only contains the brain itself, but every other brain in existence, and all the galaxies. You not only run into a computing capacity problem, but into an infinite loop: a brain that contains a representation of a universe that contains that brain. It can't happen. [Answer] **Gödel's Incompleteness Theorems and the Halting Problem proved this is literally impossible** *Incompleteness Theorem* Around the turn of the 1900s, there was a big open question in the field of mathematics. Finding proofs is kind of an art. You just work at it until you uncover a solution to the problem. Cleverness and insight play a big role. Is there something we could do about this? They were just starting to create the formal models of computation itself that would go on to become important in the development of computers (and their precursors, analog/digital calculating machines). Many mathematicians at the time expected that they would be able to find an algorithm - a concrete process you can write down - that would, given some proposition, mechanically determine whether it is true or false. But they couldn't prove it. And eventually a mathematician by the name of Kurt Gödel proved, in the 1930s, that [this is impossible](https://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems). No matter what system of formal logic you are using, either a) it's too weak to do anything useful, or b) there exist statements which are true, but which the system cannot prove, or c) the system can prove false statements (which means it can prove *anything* - i.e. it's useless). Turns out there's a way to formalize "This statement cannot be proved by system X" in such a way that it's a valid statement within system X (as long as system X is sufficiently powerful to do interesting work). Now, if the statement is true, then system X cannot prove it (because, err, that's what it says). And if the statement is false, then system X *can* prove it (because that's the opposite of what it says). *Halting Problem* Likewise, there is a famous Computer Science question called the [Halting Problem](https://en.wikipedia.org/wiki/Halting_problem). In a nutshell: I have a program. If I pass in a set of inputs, will the program enter an infinite loop, or will it terminate? Programmers would really like a tool that could always answer this question. It would make eliminating a whole class of bugs much more convenient than it is now. Too bad that it's impossible. See, if I had a tool that could answer this question, I can write a program, SmartAss. SmartAss uses the tool to see what it claims that SmartAss will do ... then it does the opposite. **Unprovable and undiscoverable things turned out to be fairly common** People started looking into this. They found out that uncomputable numbers (things that you can define, but can provably never discover the value of) are [actually fairly common](http://igoro.com/archive/numbers-that-cannot-be-computed/). Here's an interesting bit about one of these numbers, called [Omega](https://scienceblogs.com/goodmath/2008/12/31/my-favorite-strange-number-cla): > > Ω is definable. We can (and have) provided a specific, precise definition of it. We've even described a procedure by which you can conceptually generate it. But despite that, it's deeply uncomputable. There are procedures where we can compute a finite prefix of it. But there's a limit: there's a point beyond which we cannot compute any digits of it. And there is no way to compute that point. So, for example, there's a very interesting paper where the authors > computed the value of Ω for a Minsky machine; they were able to compute 84 bits of it; but the last 20 are unreliable, because it's uncertain whether or not they're actually beyond the limit, and so they may be wrong. But we can't tell! > > > [Answer] While others have given great answers, let me pose a philosophical one: # *Is omniscience even possible in the first place?* I'd argue as follows: Omniscience is knowledge of everything, meaning no matter the circumstances, there will never be uncertainty in knowledge. This would technically would constitute knowing everything about the past, present, and future as well. If the humans supposedly know everything, but continue to search for more knowledge, then they do not know that they know everything already. **Therefore, they are not omniscient.** If the humans supposedly know everything and stop searching for more knowledge, the fact they know everything is enough to change how they act which will cause a change in how the proverbial dominoes will fall. These changes will result in different information than they previously knew *somewhere* down the line, and the fact they stopped searching for more knowledge means they will not know of these changes happening even if they know it is possible the changes could happen. This creates an uncertainty factor; meaning: **therefore, they are not omniscient.** If the humans supposedly know everything and keep searching for more knowledge despite knowing there's no more knowledge to learn in order to prevent uncertainty in outcomes from happening if they do stop searching for more knowledge; then this means they acknowledge that by not continuing their search for more knowledge, then things they don't already know about could occur creating an uncertainty of the specific outcome of stopping. **Therefore, they are not omniscient.** Omniscience in and of itself is an impossibility. There will always be uncertainty, either in what will happen if you stop learning or things changing because you stopped learning and let that influence your choices. The butterfly effect is usually used to refer to time travel, but it's still worth considering for a progression of time no matter how large. In a year, what we do on Earth won't likely have an impact on anything outside our planet, but a million years from now? An explosion set off on Earth could push the moon slightly out of orbit. 100 million could knock the planets out of alignment. Sure, in the big picture, what we do here on Earth seems insignificant, but dominoes fall with every action and inaction. By choosing to learn or stop learning, a different course will set out for humanity with every moment. Every second, countless new universes open up and close off at a rapid rate just because we chose to learn or not to learn. Every choice leading to the final conclusion of the universe's heat-death. ]
[Question] [ We all know how fiction likes to play fast and loose with nanomachines. But really, what would they be capable of in real life, assuming you had an utterly arbitrary amount of them? What would the timescale be? Would you ever be able to shapeshift or use nanomachine-based superpowers, or is that all strictly fantasy no matter what limitations you put on it? Basically, what separates the IRL potential of nanotechnology in the near future from "NANOMACHINES, SON"? [Answer] # Energy Some arbitrary rearrangement of atoms that's for your designed result rather than part of a metabolism will require energy. There need to be *other* reactions to provide fuel, and handle waste products. So how do you get a pure result, and deal with available source material? # rare atoms Natural life uses what it finds and ignores what's useless. But you need catalysts to work on whatever stuff you want to break down, not ignore it! So you need various catalysts, and these often use small quantities of unique and rare atoms. Which happen to not be in the stuff you’re processing! # logistics So, you need feedstock suitable for *doing your work* as well as the stuff in-situ that you are supposed to be working *on*. Your work will produce wastes and byproducts, as well as the result you wanted. --- # Example So, the character says “deploy the goo! Develop a program to replace this volcanic outcropping with a marble palace.” And the minions sigh, and *haul away* the basalt to a dumping site, consuming energy produced elsewhere, taking large quantities of working material sourced elsewhere; then locate calcium carbonate elsewhere. Oh, no prior life to produce limestone deposits? Well, dig through the crust to locate sources of calcium, taking boatloads of energy to do so, taking 100× the structure to make the roots to achieve this. Meanwhile, decide which source of carbon and oxygen to use—if a CO2 atmosphere, grow processing facilities using *other* raw materials and feed it lots of energy to crack the gas. So finally you have the feedstocks needed to produce marble. Take that, along with other materials needed to grow the machines needed to *do* that, to the site. As well as marble deposited in-place, there will be wastes to carry off. And finally the machines need to withdraw and be disposed of. [Answer] First, decide what you mean by Nanomachines. The usual rules for Nanomachines involve: * **Artifices**. These are machines, not life. They do not evolve in unpredictable ways and are inherently digital. Seeding a planet with appropriate microbes does not meet your story goals, nor using machines to modifying local biota to make the beautiful rafting trees (as in *[Titan](http://rads.stackoverflow.com/amzn/click/B009KUXCBK)*). * **Programmed**. Dropping the machines has a definite goal. For example, *[Engines of Creation](https://en.wikipedia.org/wiki/Engines_of_Creation)* builds a city and hatchery for a foreign race. * **Replicating**. You only seed a few of the machines. Finding local resources, they create more machines. This whole colony is the factory. This model of [self-replication](https://en.wikipedia.org/wiki/Self-replicating_machine) is attributed to Von Neumann. Now make a few decisions: * **Goo**. Goo is made with the simple rules, with Gray Goo being 'reproduce at all costs'. Aside from the Gray Goo scenario, there are useful models. Asteroid mining programs could be a simple as "create two copies of yourself; fill up cargo with a gram of gold; go to the mining beacon; die", leaving some other tool to gather up the gold mountain covering the mining beacon. The alternate is the deeply programmed model. Dense storage in a DNA style molecule would allow complex behaviors with the obligatory gigabytes of cruft for compatibility with old versions of the operating system. * **Emergent Behavior**. Each machine does its thing and the end goal arises from the combined self organized system. For example, surveying nanobots would each try to get a little ways away from any other nanobot before expending itself to make a reading. The mineral map would be the aggregate of each of the datapoints reported by a robot. The alternate is networked behavior where the nanobots communicate over wireless links, direct contact, or hub and spoke systems. * **Single Shot**. A single shot of nanobots tries to accomplish a single mission and then die. For example, *source gas* in [Transmetropolitan](http://www.raintaxi.com/transmetropolitan-one-more-time/) is good a for a single interview and then goes inactive. The job might take years, for example, sequestering carbon, but only one simple goal is achieved. The alternate is a bootstrapping approach, where the nanobots follow a growth and alteration program. For example, they might survey, choose a site, build a solar plant, use the power to make simplier nanobots, create a base, fill it with supplies, and then wait until humans arrive. Once you have these decisions now you have some questions: * **Energy Source**: Unless you use Deus Ex Machima and supply the nanobots with some shared antimater, you need energy. Most energy is liberated on macroscales, even [FOOF](https://en.wikipedia.org/wiki/Dioxygen_difluoride) provides only a bit of energy in the scales of nanomachines. One pretty much needs to assume either an efficient high-density battery or great energy transmission. Still, most nanobot missions will start with creating a power plant. * **Armor**: The world is a hostile place, full of cosmic rays, radioactive alpha and beta particles, reactive oxygen, and stuff. Nanobots need to repair or defend against the environment in some way. Vacuumn work spheres [might work](https://physics.stackexchange.com/questions/71027/is-it-possible-to-create-a-vacuum-ballon-using-concentric-partially-pressured-sp). Fast assembly might work. * **Complexity**: The complexity of a successful intervention with nanobots is staggering. Start with the idea of understanding a landscape solely from single point measurements, go on to how to extract minerals and working materials, and continue onto running a major industrial complex under computer control. Whole industries creating small tweaks and software for nanobots is not unreasonable. Even if your story is hand-waving over the physics, stating that the handy container of nanobots is the result of decades of innovation and work would be worthwhile. [Answer] Nano tech is limited, like most other things, by the amount of energy it has access to and the material it can work with. Nanites can manipulate matter at the atomic scale so as long as they have the atoms to make something, they can do the thing you want them to do. This ranges from repairing DNA and cells to creating planets. If they have the material, energy, and instructions to do so they can do it. As far as Time scale goes. That depends on distance to material and goal combined with travel speed and amount of nanites that there are. That's they could probably travel a few feet per second, lets say 1m/s. Assume all the material you need is at the edge of a 1m^3, have 1 nanite, and have a structure that will take up half the volume of the cube. Find how much material that is in atoms and then multiply by 2 because a nanite can carry one atom at a time and a round trip would take 2 seconds. This gives you how long that structure would take to be made with 1 nanite. For every extra nanite divide by that number of nanites. Basically, think what you can do in minecraft with just picking up and moving blocks around. That's what you can do, on our level, with nanites. There is however Femto- level tech which is the next level and likely will be called nanites just because people aren't too good with distinguishing things that are very similar to them, but on our scale their abilities could be very magical looking. Where nanites can manipulate atoms, femtites would be able to manipulate quarks. Nanite manipulation could cause all types of chemical energy to be released, but once we get to Femtite manipulation we're dealing with nuclear energies and building atoms. Nanites you have to have the atoms to move around, Femtites you need the quarks from the atoms to make whatever atom you want. You couldn't change the mass, but you could change what it appears to us as. Let's say you want to create an iron statue. Nanites would require that there be iron around to make the statue. If there is no iron around they can't make it and if there is iron in their search area but far away they have to travel to get it. Femtites on the other hand could just pluck quarks from the matter around them, create the particles/atoms needed on the spot, and provide you the statue. Want the statue to be gold? The Femtites just grab the particles needed and add them to the Iron atoms to make them gold atoms... Of course that's assuming that doing this doesn't blow things up, because doing this could cause nuclear explosions since a brute force way of doing this is how nuclear bombs work. So again, when you think Nanites, think Minecraft more or less. When you think Femtites, think of what would appear to you as magic and alchemy, even though it is still essentially minecraft. ]
[Question] [ Assume that this earth is celestially equivalent to ours: e.g. same solar system, same position, same orbit, etc. Would the sunset look similar to ours on a floating-island earth? The earth itself is essentially masses of land orbiting in stasis around a fixed "center". Each is spherically shaped and large enough to hold about 500 people comfortably, but spread out from other islands so that one can narrowly see one island from another. There is no land mass in the center of the earth. (This would cause other scientific problems, but for the moment I'm overlooking those; and besides, those problems have been addressed in [other questions](https://worldbuilding.stackexchange.com/questions/33513/can-airborne-floating-flying-islands-be-scientifically-possible).) My question is, scientifically, would a sunset on this earth look similar to our sunset? Specifically, would it scatter as much as our sunsets do? How long would it be? [Answer] I am going to suppose the atmosphere is much like ours too. As Michael said in his answer, there might not be a truly dark night. There would also be other bizarre effects. One thing about our atmosphere is that it is relatively thin, compared to the planet as a whole. You go a hundred miles up, and you are practically "in space" (I am going to skip a scientific discussion about what being in space really means for now). The point is, you never have more than a few dozen miles of air filtering sunlight for you. If your planet is as large as Earth, though, at "midnight" you may be looking at the sun through an eight-thousand-miles-thick air filter. This will have some bizarre effects. [Rayleigh scattering](https://en.wikipedia.org/wiki/Rayleigh_scattering), which is what makes the sky seem blue, will have spread the blue-most part of sunlight so much that you won't see this color. The sun would look dimmer, hazy, distorted, and more orange-reddish. The atmoshere between you and the sun would also look this color. And I am not even counting on the filtering effect of the heavier gases that would surelly accrue on the mass center of your planet. These might tint the sun and the world another color at night. You'd still better avoid looking directly at the sun this way, though! [Answer] It would never really be night on this world. Night on earth is essentially being on the half of the planet that is currently being shaded from the sun by the entire planet. If I am picturing your world correctly, the earth is replaced almost entirely by empty space with a few bobbing masses of land floating through the air. While the side of each of these masses that faces away from the sun would be out of direct light, there would be enough light refracting around the edges and reflecting from the sky to always have a day-lit sky. "Sunset" would simply be the sun slipping behind a nearby hill without the reds and oranges of a traditional sunset. ]
[Question] [ In [this](https://worldbuilding.stackexchange.com/questions/31915/temperatures-on-a-planet-with-long-days) question I asked about temperatures on a planet where a day last 30 days. The data are the same: * stellar flux of 1.118 * albedo between Earth's and Mars's * atmospheric composition of 18% oxygen, 13% argon and 69% nitrogen * sea-land pressure of 0.87 atmospheres * land covered by water is 13% * axial tilt and the eccentricity are neglible If it's useful, this is the map: [![enter image description here](https://i.stack.imgur.com/1fXAL.gif)](https://i.stack.imgur.com/1fXAL.gif) How would maximum and minimum temperatures change (between night and day and across latitude) if a day last only 14/15 days? How would this affect the weather? [Answer] The average equilibrium temperature can be obtained from the [Stefan-Boltzmann law](https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law), for your data 293.5 K (20 C). Compensating for the Earth-like atmosphere, (+15 K for Earth, closer to +12.5 K for this planet), we have an average temperature of approximately 306 K (33 C). Quite hot, as expected from a higher solar flux, and smaller albedo. Another useful average we can get from this law is the equatorial average, 311 K without the atmosphere, ~323 K compensated. Equations for temperature estimations without an atmosphere: Effective influx: $= solar flux \* (1-albedo)$ Global average $= \left(\frac{I\_e}{4\sigma}\right)^{\frac{1}{4}}$ Equatorial average $= \left(\frac{I\_e}{\pi \sigma}\right)^{\frac{1}{4}}$ Stationary sun-in-zenith average $= \left(\frac{I\_e}{\sigma}\right)^{\frac{1}{4}}$ Where $\sigma$ is the [Stefan-Boltzmann constant](https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant) ($σ = 5.67×10^{-8} W m^{-2} K^{-4}$), and $I\_e$ is the effective influx. For a rapidly rotating planet, use the equatorial average for the equator temperature, for a very slowly rotating planet, use the sun-in-zenith equation for the peak temperature. For a case in between those extremes, use something in-between those equations. Your planet seems to be divided into two regions, a lowland and a highland. We find the highest temperature variations on the equator part of the highland, where a necessary low cloud cover gives huge, desert-like variations, reaching almost 90 C shortly after noon (actually 130 degrees C if we calculate the black-body equilibrium, but we must compensate for atmospheric convection), and less than 0 C degrees (perhaps as low as -15 C) shortly before dawn. In the lowland, the atmosphere, combined with clouds formed by the lakes ,gives more inertia to the system, thereby limiting the variations. (0 - 50 degrees C). [Answer] You're looking at much the same answer as for your previous question. A lot of the stability in temperature on Earth is caused by the specific heat capacity of water. It warms up more slowly and cools more slowly than the land. Your planet has relatively very little water, which will cause greater temperature variation to start with. On top of that you've got these long days allowing it to heat up and cool down that much more. During the day it's going to be hell outside, at night hell will freeze over. [Answer] The Earth maintains nearly-constant average temperature due to its oceans. Not only do the oceans act like a huge heat-sink, storing and releasing energy as needed, they also move energy from the warm equator to the colder poles. Without oceans, the temperature will only be limited by the heat absorbed by the ground - so not a lot. The atmospheric density is slightly lower than Earth's as well, which means even less temperature regulation. With only 15% of your world being ocean, my guess is that the global climate of the world would somewhat resemble the [climate of Mars](https://en.wikipedia.org/wiki/Climate_of_Mars#Temperature), though with slightly higher average temperature. Mars' average maximum and minimum temperatures are -7 to -82 C (19 to -116 F) in the winter, and 4 to -73 C (39 to -99 F) in the summer. However, the long days and nights will grow that gap severely. I don't have any hard numbers, just guesswork, but my guess is that the cold temperatures will reach past -150 C (-238 F), and the hot temperatures will be at or above the boiling point of water. Human life would struggle to survive in domes; outside of a habitat, no human could survive except at dawn and twilight, near the water. [Answer] The daily temperature differences in high and dry places like Colorado's San Luis Valley can swing quite a bit in just 24 hour one summer in the town of Alamosa this happened August 24, 2002: Record high of 85°, record low of 33° (52° range) August 25, 2002: Record high of 87°, record low of 30° (57°) August 26, 2002: Record high of 88°, record low of 31° (57°) [stats from weather underground] Back of the envelope gives me the range of boiling point of water to dry ice as possible highs and lows. There also would be a crazy wind blowing from the cold side to the hot as convection currents would be far stronger than earth's. This would damp down the temperature range by a bit by trading it for freezing super hurricanes. It would be a great place for freeze drying meat. ]
[Question] [ So I have a creature that I think is a bit out there and likely impossible, but it's too good of an idea and I don't want to scrap it. ## Basic design I don't really have a distinct shape that I want for it right now, so for the sake of argument, let's just say it looks more or less [like the deathclaws from Fallout](http://vignette1.wikia.nocookie.net/fallout/images/e/e6/Enclave_deathclaw.png/revision/latest?cb=20110511012723). This is not by any means a final design, just a place-holder while I work out the details of their anatomy. The thing that makes these Lizards (they are reptilian) different is the fact that after they are killed (by any means other than decapitation or a bullet through the brain) and their flesh is gone (doesn't really matter how), the remaining "skeleton" can move around, feed, and, for the most part, be a normal creature. The way it is able to do this is that its "skeleton" is actually an exoskeleton housing smaller backup organs. It is much weaker in this stage. I also want it to be able to regrow its flesh and go back to being a rampaging Godzilla. ## The questions 1. Is this feasible? 2. How would the lizard regrow its body? Would it need a cocoon or could it just stretch the muscles and skin over its bones? 3. What would it need to eat? I was thinking that it could be a carnivore when it has skin (given the fact that it has more muscle mass) and an herbivore when it doesn't. P.S. I don't need the behavior to be anything specific. If you think the bones are too weak to support an aggressive lifestyle, I have no problem with that, as long as you can explain how it would behave instead. Also, I do have some magic in the world that this creature lives in, but I don't want to use it for this, so magic is discouraged. [Answer] Exoskeletons are characteristic of some insects, so maybe you could go that way. The "creature" would be the symbiosis of a reptile and a giant stick insect. The insect would provide armor and strength to the reptile by fusing with its flesh. In turn, the reptile would provide sustenance for the insect, feeding it its bones (through some kind of osmosis) that the insect would in time fully replace. When the reptile dies, the insect "sheds" it, secreting chemicals that break the bond. Such empty "shells" are sought after by insect-less reptiles because they makes them more powerful and alpha. So they never stay empty for long but, in the meantime, they are autonomous and dangerous, as they are desperate to quickly find a new host before they die of bone deficiency. When the separated insect is looking for a host, it feeds upon itself and shrinks, thus increasing the chances that, at some point, it will encounter a reptile of a suitable size. Insects can thus be much older than the reptiles they bond with, maybe carrying DNA information from long gone generations of reptiles and thus influencing the evolution of the reptile race. [Answer] It is a genetically engineered weapon designed for front-line and behind-enemy line combat. The interior is actually a biological robot which contains the intelligence and "manufacturing" functions. The exterior provides the combat, consumption and digestion components. The exterior is a product of the interior. If you've encountered one that looks like a reptile, that is probably because the last corpse that it recycled was a reptile. The interior creature can repurpose muscles, skin and organs from the recently deceased bodies of almost any species. From these cadaver parts, it builds an flesh suit which adds to its combat skills. From its living body armor, it also receives fresh blood which is its preferred source of nourishment. The outer creature eats whatever is normal for its species, while the inner creature parasitizes nutrients out of its host's blood. When disrobed, the inner creature has fangs with which it can obtain its favorite food from living sources. The inner creature doesn't so much regrow its exterior coating; it builds it, strapping on muscles, claws and other body parts wherever they best fit. Similarly, as parts of the living armor become broken during combat, the creature can shed them and possibly replace them with spare parts that it finds around the battlefield. [Answer] Well, cockroaches are able to survive without heads and only die because they can't eat, so this isn't *that* much of a stretch comparatively. I'd imagine that it would go through a period of extreme hunger in order to regain its lost body mass as fast as possible, and if not a cocoon, it would at least go into a hibernation state while it reconstructs its body. Diet is up to you, but you might want to make it omnivorous so it has a greater array of potential food sources, especially when recovering. Would the bones be actual calcium-based bone like we have or something else? [Answer] Symbiosis. The skeleton is a separate animal, perhaps like an insect or lobster with an exoskeleton. The flesh over it is a separate life, which acts as a wearable power-suit that amplifies its strength and provides protection. ]
[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/30353/edit). Closed 8 years ago. [Improve this question](/posts/30353/edit) **Nothing lasts forever, and the United States is no exception. How long can we expect it to last?** To give some context to the question, a long look at history, going through [China](https://en.wikipedia.org/wiki/Dynasties_in_Chinese_history) and Egypt (see chart below) and [MesoAmerica](https://en.wikipedia.org/wiki/Toltec_Empire) suggests that humans have considerable difficulties establishing geographically large and well-populated political entities that span for longer than 5 centuries. No Chinese dynasty seems to have even made it past the 300 year mark in 2 millennia. In fact, there are only a handful of successful examples in the entire history of humankind (If we restrict ourselves to larger entities, I can think of Portugal's colonial empire, the Ottoman Empire, and the various incarnations of the Roman/Byzantine republic/empire, with more smaller scale entities [listed here](https://en.wikipedia.org/wiki/List_of_empires) that I would probably (unfairly) hesitate to call empires. [![Egyptian Dynasties](https://i.stack.imgur.com/kADeg.png)](https://i.stack.imgur.com/kADeg.png) Now, let us consider a few facts. Technology has enabled faster flow of peoples, but populations are correspondingly larger. Human lives are longer, but also more fast paced. Technological levels are unprecedentedly high, but that might make modern societies more fragile to disruption. The US has nuclear weapons, but also humanitarian drives that, say, the Romans lacked towards what they considered 'barbarians'. The United States is the strongest political entity in the world economically and has been in this position for what is over a century. The United States is the strongest political entity in the world militarily and has been in this position for almost 3/4 of a century now. The United States has a centuries long tradition of incorporating immigrants into its body politic and gaining their loyalty. The United States has been in existence for 2.4 centuries already. **Given all that, how long can we expect the United States to last? If you think providing date-like timelines is too hard, I will also consider a discussion of the possible factors that will eventually bring down the Union as an acceptable answer.** The question of how one defines **the end** of an empire/political entity might be relevant, so I'd hazard a soft definition including external conquest, civil war resulting in dissolution, loss of the imperial heartland or of the vast majority of its territory to other entities, or a combination of persistent and irreversible demographic, economic and military setbacks that render the entity irrelevant on the world stage. For instance, a Byzantine 'empire' restricted to an area of a city state was centuries past being effectively an empire. *EDIT: After [extended discussions in chat](http://chat.stackexchange.com/rooms/32053/discussion-between-bilbo-pingouin-and-serban-tanasa), for the purpose of this question, we'll restrict the definition of the end of the USA as failing to keep all of the following: 66% of its present territory AND (66% of its population OR at least 2.5% of the world's population), AND 66% of its current constitution, excepting future growth through the amendment process.* Edit 2: I use the term "empire" to mean geographically large and well-populated political entities. This is hard to pin down exactly, but say at least 1% of the world's area and at least 1% of the world's population. [Answer] ## This Century If we restrict ourselved to the human realm, the United States will likely end the same way large, well-organized empires have ended historically, namely through demographic attrition. Rome was depopulated by a combination of oppressive taxation and endless internal political strife resulting in a severely anti-growth economic situation, making it prohibitively expensive for its citizens to raise children. Having an economy based in large part on slavery became problematic when the empire grew too weak to keep aquiring slaves militarily. The United States relies on a dominant military to enforce a de-facto tribute in the form of deficit spending in exchange for providing a Pax Americana conducive to global economic growth. It is unlikely that the growing Asian powers of China and India will allow this to continue forever. Moreover, the US relies on integrating a constant flow of skilled and unskilled economic migrants. Unfortunately, its own internal demographics favor the rise of radically fundamentalist groups with high birth rates over the skeptical and well-educated, who have historically failed to reproduce generationally. Eventually, this is bound to have consequences. At some point, it will stop being welcoming to foreigners, turn inward and start decaying. Going by current demographic trends, [hard-core religious fundamentalists will be demographically and politically dominant](http://belfercenter.ksg.harvard.edu/publication/18824/demographic_projections_predict_fundamentalist_populations_surpassing_secular_counterparts.html) by the 2070s, or in about 2 generations. Long before then however, the country will have divided itself geographically between the coasts and the inlands, with wildly diverging political, religious and cultural attitudes, to the point where there will be little to no national solidarity left between these groups. Of course, a technological singularity, if one were to occur, would render all these calculations above meaningless. Ray Kurzweil suggests that machines are on track to achieve human-level intelligence within a decade or two, and by 2040 we can expect machines that can outthink the combined bulk of mankind. Nothing i've seen so far leads me to believe that machine intelligence is not possible, or that the timelines are wildly ambitious. So in summary, **the US will likely cease to be recognizable to a current US citizen sometime between 2043 and 2080**, either due to a technological singularity or to the unalterable demographic shift and geo-segregation along political and socio-economic lines already taking place. [Answer] As early as 2015, but possibly not for a thousand years. Predicting the future is really hard, esp. if you have to be accurate. Suppose the Yellowstone super-volcano were to blow up later today. Within a month, the US would be on the verge of collapse. A flu outbreak with 90% fatalities, collapse. There are other perfectly feasible events that cause collapse in short order. If you assume economic, political, demographic collapse, etc. there are a least a few ways this could go. 1) The US debt continues to grow faster than the economy and no-one wants to loan money to the US anymore, inflation and hyperinflation soon follow leading to economic collapse. At that point, there US does not necessarily fail, we pay our debts with near worthless currency, get back to basics and start over. No-one is going to loan money to US for a long time, but the country survives, rebuilds, etc. 2) US tires of its economic stupidity and takes a more conservative spending approach. Digging out takes a while, but the country survives intact. 3) US discovers new technology that grows its economy at an accelerated rate. So much money comes in that the US pays off the national debt and becomes a lender nation again. Personally, most likely I would expect that the US will swing more conservative, as it has before -- look at its response to progressivism 100 years ago. Forty years ago everyone seems scared of Japan, but that bubble burst. China has strong bubble elements in its economy that may cause is to stutter for decades as well. US demographics will shift. In the past, the new population was Americanized and the changing population did not alter the country. For now, the new population is not being assimilated, this could change resulting in a more stable country or the trend could continue, destabilizing the country. A major terrorist attack could trigger a fundamental change away from its self-destructive tendencies making the US stronger than ever. Only time will tell. ]
[Question] [ Several hundred years in the future, technology has significantly advanced to the point where we can far more efficiently extract energy out of the natural world we live in. As a result, energy has become far cheaper, and completely renewable, significantly boosting the economy and sparking innovation. Quality of life jumps up, and with our new money, we move a lot of our focus on climate to focus on philanthropy. Using our new energy, we have drastically improved most third-world countries, westernizing them and almost entirely eradicating poverty. Another side-effect of this new energy is that climate change has become a thing of the past. It has been replaced by climate-control. We can't change the world temperature overnight, but we can safely and accurately change the temperature by a couple of degrees Celsius per year, with practically no limit on how much we change it (other than, of course, humans have to survive to continue to change it). In comparison, we have very little control over the weather, but we do have some. Everything in the world is better. There is only one downside. Overpopulation. The economy is great, standard of living is great, no energy crisis, but we are running out of land for the people to live in. We also need more room for agriculture. Space colonization is out the window, as our space travelling abilities have not progressed very much since modern day. However, we have another weapon: Terra-forming the earth. 70% of the surface of the earth is water. If we can bring that number down, we will have more room. How do we go about this? When the idea first came to me, I thought "Bring the temperature up! That way, more water will evaporate, the ocean levels will fall, and previously underwater land will become beach, previously beach will become habitable land!" I immediately realized that this is a terrible idea. This would * Melt the poles and bring the water level up, * Destroy a lot of agriculture, * Make a lot of desert areas uninhabitable, * Make humans pretty grumpy and probably a million other things that I can't think of at the moment. Then I thought "Let's bring the temperature down! More water will freeze, growing the poles and lowering the ocean levels! If we're lucky, some of the poles might even become habitable!" Again, this is a terrible idea, causing * Destroying agriculture with snow, rather than heat, * Increase condensing of water vapor, possibly increasing the water level? * Potentially cause a new ice-age * Again, most humans would be pretty grumpy about the cold. Then on the extreme ends of the spectrum "Freeze all the water, humans could live on the ice!" (probably a bad idea) or "Melt all the water, humans could live in the desert that used to be the ocean floor!" (Very clearly a terrible idea) So here's my question: How bad are all of these ideas? I could be totally off, as I am not really a scientist. Assuming the technology exists, can earth pull off any of these? Is there any **practical** amount of climate change that could improve the world and make more land? [Answer] Any drastic change, and by drastic I mean 1C - 2C change by 2050, has the potential to wreak havoc on agriculture, fishing and the global economy, not to mention wildlife. Let's start with wildlife. Wildlife has adapted to the current climate over the last 10,000 years or so. Changing it even so slightly will cause species to migrate thus causing disruption of food chains which could lead to die offs. Agriculture & fishing are directly related to that. Changes in temperatures will change the growing/migration patterns, type of crops you can grow, the type of pests common in each area will change, etc etc. Finally changes in the temperatures can alter the salinity of the ocean, the prevailing winds, and/or ocean currents. A country that was once lush and green can become a desert and another can be flooded by rains leading to all sorts of political tensions. Making land is not that beneficial anyway - there are huge swaths of land that are almost uninhabited, such as the mid west, Canada, Alaska, most of Russia, etc. The negatives are simply too great, while the positives are slim at best. [Answer] Warming the climate a few degrees has already been shown to be both possible and feasible for human civilization. If this was 1100-1400AD, we would be importing food from farms in Greenland and wine from Scotland. The reason we don't do that today is that it is too cold to farm in Greenland or grow grapes in Scotland, so the historical evidence for a warmer climate exists. The evidence for a colder climate exists as well, since the average temperatures started to fall in the 1400's (causing the Vikings to abandon Greenland and eventually shifting wine making to France and Spain), climaxing with the Little Ice Age. At that point, crop failures were common, creating a great deal of instability in most nations. Many wars were happening at this time, driven by both the desire to gain potentially productive territories, and due to the logistical ease of transporting heavy equipment or marching armies across frozen waterways. The "Great Northern War" between Sweden and Russia (1700-1721) was one example in Europe, and in the Americas, the American Revolutionaries achieved some victories by being able to transport cannon across frozen rivers. (100 years later, Civil war generals did not have the same ability, since rivers were no longer so hard frozen in the same landscape). [Answer] Possible but unlikely, and *extremely* difficult to control. Say you want to warm Earth to turn tundra into fertile farmland. * How good is the topsoil in the newly temperate zone? * Could it be that you'll get plenty of swamps and mosquitoes instead of farms? * Will changes in rainfall mean that rivers burst their beds? But the main issue is that there will be winners and losers from the change. As subarctic regions turn temperate, temperate regions turn subtropical. The people in the temperate regions are bound to complain, and that's where powerful nations are located. Consider how the US would feel if Canada wanted to heat them up just so *Canada* can become balmy. [Answer] ## Reality check? Let's do that! * Current cities population density, as reference [List of cities proper by population](https://en.wikipedia.org/wiki/List_of_cities_proper_by_population) is from 30000 people per square km to let say 1000 people per square km. I live in city with 3500 people per square km, and it's pretty ok, if move factories away it could be excellent. So let's stick with 1000 ppl per km2 as an easy and good number. * Food is different story, and depends on climate zone. Mild, cold sided mild regions produce 400 tonne per km2 per grow season in good case scenario. Usually there is not only a bit of cold, but not much light for plants to work with, that's main limiting factor for production, compared to regions where instead cold, heat is a problem. Vegetable to meat conversion ratio, depends, but is something around 1.5 for fish, 3-4 for meat. You have 3 kg weed so you get 2 kg fish or 1 kg meat. I may a bit off with that things, but it is something nearby. So let say we need 5 kg weed per day per person - to keep him full. And that limits population to 220 happy people per km2, some are fat so 200 people per km2, some are wasteful fit so *let it be 100 people per km2*. So if we compare cities population density 30000-1000 ppl/km2 with food production needs 100 ppl/km2 * **there is no such problem where to live, there is a problem where to grow food.** ## Where to grow food? Where is not a big problem, actually. It's more the question how to grow? For how many people? As we wish to preserve or even maybe improve our current bio-environment, in some places, so let pretend we care about it. But as we have problem, someone have to pay, and die. Between these opposites, we have solution - deserts. There is live and interesting live, but OP have problem, we have to sacrifice their environment. But as who cares - we will preserve them in zoo and any other methods we have. ## Deserts * [List of deserts by area](https://en.wikipedia.org/wiki/List_of_deserts_by_area) For food production we need sunny desert, and Sahara with 9'000'000 km2 is obvious choice to discuss. It's not only one choice, but biggest one. Subtropical deserts in that list are 6'607'000 km2 combined. Desert is good, because more sun, longer sun season. So if make all properly, it will give at least 3-4 times more weed then in mild-cold climate. So just Sahara may give food for additional 2.5-3.5 \* 1'000'000'000 people. Yes, you have to work for it to happen. Use technology luke, build greenhouses, build water channel, recycle water, reuse water from humid air, use day-night temperature difference to your advantage, think think - it's doable. Yes, it will affect earth climate in some way, but at least not so stupid and wasteful like heating some parts of earth. So using only deserts we may feed +6'000'000'000 more people as it is now, at least, practically with old style technologies, combined with some current tech. ## Real problem is? Real problem is energy. If we have energy sources, stack 10 store, 100 store Sahara desert greenhouse Inc building. There is plenty of useful sand to use. Not so simple, CO2 may drop significantly - that will be some limitation factor, but we have plenty fossil fuel to burn. Amount of available Carbon may be a problem. Heat dissipation may be a problem, or may not be a problem - depends on energy source, thermonuclear reaction theoretically are way more efficient then combustion cycle. [Carnot cycle](https://en.wikipedia.org/wiki/Carnot_cycle) temperature of the hot reservoir is millions of K, cold reservoir thousands for K. ## Space Space is also question of energy, if we have much and cheap, cheap enough to heat earth, so we do space, cheap and in huge quantities, even if technology of getting in to space did't moved a single step forward and is as it is now. ## Terra-forming earth * Terra-forming the earth. 70% of the surface of the earth is water. If we can bring that number down, we will have more room. How do we go about this? **Strongly not recommended.** Until you will know it enough, to not to loose information, but make information. Ocean is place to live for many creatures. I do not care about their lives, human lives are more important, but loosing so much genetic information, bio-chemistry, bio-diversity, connection to our past - just loosing all that information, which is result of hundred millions years of collection of it, testing it, which is source for us to learn - it's a shame. Problem is, to make that information again, we have to spend thousands of years, in space stage, using way way more energy then we use now. And some bits of information may safe us or help to answer on questions. Waste thousands years of our future civilization, just because we are to lazy spend 10-20 year now - what sort of thinking is that. It's not just solving our current problems in better and high quality way, it's about surviving our species in next 10-20k years. There is better and easier way to solve our problems - **Space**. No matter how much you terra-form The Planet, you will end with same problem, very soon. ## Space is our answer and our future home. [Answer] Is the world's present temperature the optimum temperature to maximize the amount of food the world can produce, and simultaneously maximize human comfort, and simultaneously preserve other forms of life, and simultaneously be the absolute best for every other factor you can think of? I'd guess not, but even figuring out how you would calculate that would be awfully difficult. It may well be that someday people will have the technology to alter the climate in beneficial ways. But I think that would be more complicated than just raising or lowering the global average temperature. I'd imagine it would involve redistributing water supplies, altering prevailing winds, etc. There's also the problem that things that benefit one group of people might harm another. Like increasing world temperatures a degree or two is probably good for people who live in Norway, but not so good for people who live in Libya. Or even in a single place: Reducing the amount of snow might be great news for farmers and loggers, but bad news for people who run ski resorts. Etc. [Answer] Increased CO2 causes plants to use water more efficiently. Crops yields of some grains will increase, others will decrease, thus mitigating the effects of climate change. See <https://wattsupwiththat.com/2016/04/20/columbia-university-begrudgingly-admits-the-benefits-of-co2-on-crops/> > > Based on the current biomass of these crops, water-use efficiency > would rise an average of 27 percent in wheat; 18 percent in soybeans; > 13 percent in maize; and 10 percent in rice. All things considered, > the study projects that average yields of current rain-fed wheat areas > (mostly located in higher latitudes including the United States, > Canada and Europe), might go up by almost 10 percent, while > consumption of water would go down a corresponding amount. On the > other hand, average yields of irrigated wheat, which account for much > of India and China’s production, could decline by 4 percent. Maize, > according to the new projections, would still be a loser most > everywhere, even with higher water efficiency; yields would go down > about 8.5 percent. The study is less conclusive on the overall effects > on rice and soybean yield. > > > The deserts are greening as a result of increased CO2: <https://wattsupwiththat.com/2016/02/16/study-increased-carbon-dioxide-is-greening-deserts-globally/> > > The analysis also showed that elevated carbon dioxide significantly > enhanced soil water levels in drylands more so than it did in > non-drylands, with soil water content increasing by 9 percent in > non-drylands compared to 17 percent in drylands, Wang said. > > > There is a debate over whether warmer winters will save more lives normally lost to cold exposure than the warmer summers will kill due to higher temperatures. See <https://wattsupwiththat.com/2015/06/18/study-global-warming-wont-reduce-winter-deaths/> in which the models say warmer winters won't save many lives but the actual data (a chart) shows that excess deaths between winter and summer have been steadily declining. [Answer] ## Micro scale terraforming A world average temperature is not really a useful metric for optimization anyway. Global increases may mean local decreases in some cases or vice versa as weather patterns change. What *may* help, however, is small scale terraforming to do things like improve food yield and predictability in a given area... and [we're already doing that.](https://youtu.be/Tpozw1CAxmU) So instead of making sweeping global changes aimed at an arbitrary average, your engineers could focus on improving temperatures and weather patterns on a more local level. Take a dry rocky area and improve the availability of water, whether by rain, irrigation, or just improving the capture and retention of rain that already occurs, and start growing plants that do well in rocky soils. Over time those plants will die and contribute organic material to the soil that will increase the range of things you can grow there. Plants with strong taproots can change their microclimate all by themselves if they can live long enough to reach groundwater, or others even just by catching more moisture and holding it instead of allowing it to run off/blow away. Life has been terraforming this planet since it started here. ]
[Question] [ In Back to the Future III, there is a scene where the professor has built an ice cube maker with 'wild west' technology. I'm not actually sure if that's possible, but given a solid understanding of Boyle's law and compression stages, it's something that feels like it should be possible. On a parallel line of thought - I attend events with re-enactors regularly - medieval era - late 1400s. One of the things I've pondered - what things could I legitimately make using medieval techniques, but that will cause the re-enactment purists to get upset because the use of undiscovered scientific principles. Steam power seems a reasonable line of thought - whilst Hero made a Steam Engine, the 'real thing' wasn't really used until much later. Or perhaps - as first alluded to - some refrigeration mechanism. What else could be feasible? For bonus points, things I could easily transport to a campsite in the back of my car. [Answer] **Lightning rods** I remember reading one of Asimov's essays trying to show the importance of them in the fight between science and religious zealots... there had been scientific advances opposed by the Church before, but even when it was stablished that science was right, most people did not care (for example, the Sun moving around Earth or the other way around has no real implication unless you study the movement of stars and planets). Lightning was the archetypical "divine" punishment, it came from the sky and could kill one or another people almost at random; no one was safe (and of course, everyone was a sinner to begin with). It was easier to explain that, say, floods or plagues that killed saints and sinners altogether. Now the lightning rod meant that such punishment was controlled. Even worse, if the priest kept insisting that it was an impious invention and refused to use one, then the church would be eventually struck (churches being usually tall buildings) by lightning while the "impious" buildings would be safe. [Answer] ## **If I had only known...** Given the metallurgy of 13th century Europe, and a transfusion of scientific knowledge, what inventions could have been made? Adding a single, large book called the [Machinery's Handbook](http://rads.stackoverflow.com/amzn/click/083112900X) to the library of blacksmiths and armorers in Europe would have transformed industry. A tiny example, is that everyone adhered to the bolt thread counts specified in the Handbook, suddenly bolts and nuts are inter-operable. While mass production may still be a few decades away, the ability to make inter-operable parts cannot be understated. The Handbook covers such diverse areas as: * Mathematics * Mechanics and Strength of Materials * Properties of Materials * Dimensioning * Gaging and Measuring * Machining Operations * Manufacturing Process * Fasteners * Threads and Threading * Machine Elements Not having to reinvent all these areas gives blacksmiths and machinists a huge leg up. Part of what took so long back then was that standards had to be invented then those who were on a different standard (if any) were dragged into the new standard. Exposure to things that we take for granted, like a standard system of measurements (the metric system) would have blown their early minds. Lots of things can be made from Iron and low quality steel if you've got a means to make accurate measurements. Many things are easy once you know they can be done. [Answer] Since Green already provided one of the smartest things, i would like to humbly add a small and simple, yet extremely hady device: The lighter. Since people relied entirely on fire for lighting and heating, and the fiddling with flint and tinger, or the constant tending of the fire, must have been quite a nuisance. Especially when one needed a small fire fairly quickly, say somewhere out in the fields or in the forests, a lighter should be able to make a huge difference. And if you take a look at a Zippo (R), it cannot bne that hard to create something similar, once the principle is known. [Answer] Reinforced concrete. Given that iron/steel and concrete are both ancient materials, I would have thought it possible to combine them. However, the metal parts would have to be manually created by smiths and the cost of it as a construction material would probably far exceed quarried stone. [Answer] I'll give two categories. First, things you *can* transport in your car: **Water purification systems** Disease was one of the biggest killers in medieval times. Any one of a number of simple technologies could lower that death count, at least for the wealthy. The best options would be distillation and filtration (tubes packed with sand). **Batteries** Galvanic cells go back at least as far as the [ancient Middle East](http://news.bbc.co.uk/2/hi/science/nature/2804257.stm). However, it is not known what use they might have had beyond possibly shocking people. Basically, ancient gag gifts. They could potentially be used for treating metals, but possibly not under the conditions or with the other materials available in medieval times. I am not sure what other uses medieval society might have for low-quality batteries. **Tin can telephones** Do I need to say more? Additionally, other auditory tricks might be useful, like [acoustic mirrors](https://en.wikipedia.org/wiki/Acoustic_mirror), which could be used to send messages quickly within larger cities/fortifications or possibly detect where enemies are located. --- Now, things you *can't* transport in your car (or might not be physical things): **Vaccinations** The idea occasionally popped up of vaccines, but the idea failed to gain traction until after germ theory. If you could sell the idea (it *seems* like a bad one) to the people of the time, it would go a long way. **Cannons** Gunpowder is fairly simple to make. Cannons are not that much harder to build, and quite obvious once you have an explosive. Introducing gun powder would completely change medieval, architecture, and politics. **Angled walls (star forts)** While it would not be as large of a help without the above mentioned cannons, angling the walls of castles would help to deflect projectiles. If cannons are not around and you are protecting against catapults, the angles would ideally be only horizontal - as a vertical angle could actually increase the damage done. [Answer] You'd be surprised. Making things like wire is harder than you might think. You actually need reasonably high purity materials to avoid occlusions, and you need decent equipment to make the wire. My suggestion would be to explore what tools and materials are needed to make such an anachronism, and make sure you've got similar tools and materials available in the world. For a sense of just how hard it is to make things on your own, I recommend a TED talk on [how to build a toaster](http://www.ted.com/talks/thomas_thwaites_how_i_built_a_toaster_from_scratch?language=en). [Answer] My thought would be electricity related - extruding wire isn't too difficult (pins can be made) so creating coils of wire. Making a magnet to start generating isn't easy, but you can create them from scratch using iron - heat in a magnetic field to align the atoms. Initial current you'd have to get creative, but a chemical reaction of some kind (like the potato power source). Then you've got a generator that you can use to do .. well, all sorts of things really. But an arc-lamp might be a good example of anachronism. Being a source of non-flame based light in an era where such things really don't exist. [Answer] I would have thought that you could build a rudimentary bicycle using treadles (chain and sprocket might require more precision engineering than was available). Without pneumatic tyres or shock absorbers it would not be a pleasant ride or particularly practical on the roads of the time. [Answer] Bear with me here, but in essence medieval technology had all the needed bits for rudimentary combustion! * Distilling was a practice already known, and alcohol could be made. So, fuel is available. * Pistons, likely the hardest part, can be achieved (like most other parts) through moulding and casting. * Like another answer mentioned, the principles to build a lighter already available. Mechanically lining this up based on other parts would be tricky but not impossible in order to build an igniter. Fact is, you could likely build most of Ford's original engine or even improve on it. ]
[Question] [ After receiving great answers on my [previous question](https://worldbuilding.stackexchange.com/questions/16713/how-long-could-the-survivors-of-a-nuclear-war-maintain-a-civilized-way-of-life), I've thought hard, how to create a story, in which there is a large-enough group of people (at least 100 highly educated people and enough others, who provide for them) in a post-apocalyptic world, which have a way of life comparable to ours (at the very least - they know, how to read and write and believe in reason more than in any deity). Imagine that 1. the US drop all the nukes they have on Russia, 2. the Swiss learn early enough about that to put as many of their citizens into bomb shelters (allegedly, Switzerland is the only country, which has [bomb shelters](http://www.swissinfo.ch/eng/bunkers-for-all/995134) for 100 % of the population), 3. Russian guaranteed retaliation system nukes the US automatically (automatically because most people are dead from the first strike) and 4. the Chinese also nuke the US after the attack because they had a secret pact with the Russians (that's part of the story). Let's assume that Switzerland wasn't nuked neither by the Americans, nor by the Russians, nor by the Chinese (but its environment may still suffer from global effects of the nuclear war). How many Swiss without damaged DNA are likely to survive 100 years after the nuclear war, provided that 1. they adopt strict mating protocols, 2. 100 % of their population was in the bomb shelters at the time when the first bomb exploded, 3. they manage to establish connection to other people in the bunkers and 4. the environment isn't completely screwed up (e. g. the climate in Switzerland doesn't get significantly colder due to a [nuclear winter](https://en.wikipedia.org/wiki/Nuclear_winter)) ? Extra credit: Does the fact that Switzerland is a country with lots of mountains make it easier for a post-nuclear society to survive, or harder than in a "flat", low-altitude land? [Answer] I don't think the bomb shelters will matter much. There are two options: * **Our ecosphere is wrecked.** No matter how many Swiss survive the initial strikes, they're gone. They might have some preserved food in their bunkers, but they don't have greenhouses. After weeks, months, or years, they have to come out and look for food. They find nuclear winter and contaminated fields. They die somewhat later than people without bunkers. * **Our ecosphere is not wrecked.** Then the DNA damage you're worried about won't happen, either. [Answer] I propose that in an 'all-out' exchange, there would be zero survivors, anywhere in 100 years. There is a profound difference between a 'Fallout Shelter', a 'Bomb Shelter' and a 'Nuclear Bunker'. The levels of radiation you are describing would *eventually* find their way into any underground structure, regardless of type. To prevent this, a shelter would require an almost spaceship-like self contained environment, no air, food or water from the outside, for a century. I suggest as a reference, read "level 7" by Mordecai Roshwald . It provides a view of a survival effort much like you have described. ]
[Question] [ Taking genetic manipulation of humans to change them to live in other environments, besides maybe gills what other physical changes would need to be done for a human to spend 95+% time living in the ocean? I also suspect gills would only be partially useful, allowing longer submersion's but still require trips to the surface, like dolphins and whales. People like structural homes but dependence on these should be kept to a minimum. The humans should be able to dive a little deeper than regular people with SCUBA gear. [Answer] I'll break this down into two sections: Basic Survival and Comfortable Living. **Basic Survival** *Either gills or enhanced lungs/oxygen efficiency.* Gills: Permanent operation underwater. In order to be truly effective, you would also need a way to pull water over the gills without moving. Some species of shark lack this ability, and it results in a need to constantly be moving in order to breathe. Sticking with air-breathing: Humans are very inefficient at extracting Oxygen from inhaled air compared to dolphins. A human captures about 17% of the oxygen from a breath, dolphins capture 80%. You would then need to increase the concentration of hemoglobin in human blood to allow for greater oxygen storage within the body. It would also be necessary to remove 'breathing' responsibility from the brainstem and move it somewhere that is only conscious. Since breathing would become less common than not breathing, you don't want that wired to the autonomic nervous system. It would also be ideal to develop a way to seal the nose and sever the respiratory system from the mouth so that you could eat underwater without drowning. Increased lung capacity is only so effective, as you will see in the Pressure Regulation section below. *Digestive System* Humans are now immersed in salt water 24/7. Drinking salt water dehydrates humans, so you would need to tweak their digestive system to filter out all that extra salt content and expel it in their urine. Alternatively, some aquatic mammals extract all the water they need through their prey, and don't actually swallow salt water. This would require humans to be able to consume the blood of their food without getting sick on it, and be able to extract the water from that. *Physiology tweaks* We would also need to tweak our dietary requirements. Vitamin C is hard to come by in the ocean, after all. Don't want everyone to end up with scurvy. Additionally, reduced exposure to sunlight means humans would synthesize less Vitamin D. Lack of Vitamin D leads to things like depression and moodiness (oft referred to as Seasonal Affective Disorder). There are a number of other tweaks that would need to be made here as well. *Pressure Regulation* SCUBA divers need to either take numerous stops on their way back to the surface to avoid getting 'the bends', which is what happens if you depressurize a human body too quickly. The structure of the middle ear would need to be altered to protect them during deep dives. You may need to make exhaustive modifications to the nasal structure so that it can freely collapse as well, and not put pressure on the cranial area. Additionally, if an air-breather, the lungs would need to be heavily reinforced (and allowed to safely collapse in such a way as to force all held air away from the alveoli) while deep under water to prevent air-exchange from occurring. This would protect against the insertion of Nitrogen into the blood stream, which is a common cause of The Bends. *Eye Protection* The human eye doesn't like salt water, and it doesn't do well with high pressures. It would need to be remodeled to both have a protective lens over it (possibly mobile) to protect it from the salt water, and would need to be reinforced to survive pressure changes. **Comfortable Living** *Natural fins* It would be advantageous to lengthen the toes and fingers of an aquatic human and web these appendages together. This would allow for greater propulsion through the water. *Alterations to arm muscle structure* It is hard to move quickly in the water, and surviving against possible predator attacks is difficult, even when armed. This is because the human muscular structure is configured in such a way as to permit dexterity and range of motion, rather than strength. Either the muscles in the arm would need to be bulked up, or their attachment points would need to be shifted further along the bone, giving greater leverage to the muscle. Bones may need to be reinforced as well to support the increased strain. *Temperature Regulation* While our divers could make due in thermal suits, it would be better to give them a natural way to stay warm while in the cold ocean. A higher metabolism would allow their body to produce more heat, and a subcutaneous fat layer would provide insulation (aka blubber). *Enhanced dark vision* The ocean is really dark once you get down past about 300 feet, and normal humans would need light all the time. Blue light penetrates the deepest into the ocean, so modifying the eyes to be more sensitive to that shade, and tweaking pupil size to allow for more light to be collected would improve the depth at which humans could see *Alternate means of sensing* Beyond a certain point in the ocean...eyes are largely useless for any sort of significant distance. This is why so many aquatic animals echolocate. Introducing this ability to your aquatic humans would greatly improve their underwater comfort at depths beyond which they can comfortably see. *Further physiological tweaks* Many deep-ocean aquatic mammals are capable of voluntarily controlling their own metabolic rates and heart rate. This allows them to put their body into a lower performance mode to conserve oxygen. This tweak would allow air-breathing humans to go on longer dives before needing to resupply. [Answer] [Water pressure](http://oceanservice.noaa.gov/facts/pressure.html) gets very problematic very quickly: > > The deeper you go under the sea, the greater the pressure of the water pushing down on you. For every 33 feet (10.06 meters) you go down, the pressure increases by 14.5 psi. > > > 14.5 PSI $\approx$ 99.974 Pascals That said, if humans aren't going any further than scuba diving depths, this won't be *too* hard, but for longer periods, this could be an issue. There are some solutions to this, though: > > Many animals that live in the sea have no trouble at all with high pressure. Whales, for instance, can withstand dramatic pressure changes because their bodies are more flexible. Their ribs are bound by loose, bendable cartilage, which allows the rib cage to collapse at pressures that would easily snap our bones. > > > Humans would have to adapt to this. Another issue is [temperature](http://en.wikipedia.org/wiki/Underwater#Conductivity). Hypothermia is possible in many situations. Blubber, like whales, seals, and some other creatures have, is a possible solution to this problem. [Answer] **1.** **Our fishy ancestors** > > The early human embryo looks very similar to the embryo of any other > mammal, bird or amphibian - all of which have evolved from fish. Your > eyes start out on the sides of your head, but then move to the middle. > The top lip along with the jaw and palate started life as gill-like > structures on your neck.5 May 2011 > > > Anatomical clues to human evolution from fish - BBC News > > > www.bbc.co.uk/news/health-13278255 > > > It won't be very long before we can affect the development of embryos and switch on and off ancestral traits. It is entirely possible that we could in future selectively keep fish-like traits whilst maintaining the development of the human brain. **2.** If going back to fish is unappealing then maybe we have only to go back to apes. > > [**The aquatic ape hypothesis**](https://en.wikipedia.org/wiki/Aquatic_ape_hypothesis) (AAH), often also referred to as > aquatic ape theory (AAT) is a proposal that the evolutionary ancestors > of modern humans spent a period of time adapting to a semiaquatic > existence ... the most prominent proponent was Welsh writer Elaine > Morgan, who wrote a series of books on the topic. > > > ]
[Question] [ Many of the intelligent species on Earth, including us humans, are predatory. One of the reasons for this is the nutrient content of meat; a pound of meat is very calorie and nutrient rich especially compared to a pound of plant material. One of the reasons humans have been able to be so crafty is from these predatory features: * Flexibility to run, climb, and swim (and endurance) * Omnivorous * Eyes facing forward * Opposable thumbs * etc My question is: **How can a species evolve to levels of intelligence where they become capable of space travel while not being a natural predator?** Such a species would have characteristics of prey, such as (but not limited to) outward pointing eyes, being herbivores, and with natural predators. NOTE: I'm curious about how the species could evolve into human-like intelligence, but since classifying intelligence is tricky, I've used space-travel technology instead. EDIT: Posthumously, I think my question might be too vague; so I'll specifically ask about food supply (since I mentioned it before): *What could such a species eat to allow them the necessary nutrients while still being able to invent technologies and use tools?* [Answer] First note that we are omnivorous and almost all animals are herbivores will eat meat if they need the protein and it is readily available. The issue is that carbohydrates and cellulose are primarily built out of a carbon backbone. Muscles are protein which are largely made of amino acids (nitrogen basically). The fats in meat are also much more similar to human requirements compared to the comparatively few lipids in plants. It is only recently humans have been able to adopt a vegan lifestyle as suitable plant based alternatives have been developed. Herbivores succeed by synthesizing these products themselves but this is expensive. An easy way to rectify this is to have a readily available high protein and high energy plant material which removes the need for omnivorous behavior from ever developing. This is kind of the role fruits play in the evolution of monkeys and bird (both of whom also obviously eat bugs and sometimes meat). If eating animals is dangerous but plants are easy, eat plants. If they are alien, make blood fruits or something which where amino acids absorbed by the roots deposit or large nodes on nitrogen fixing plants. You could also make carnivores or scavengers that you can argue aren't really animals so don't count (kind of like sponges, jellyfish, or plankton). A hole in this is that a large amount of readily available food will result in overpopulation until the food is now scarce. Meat then becomes an attractive option again. There must, therefore, be other factors discouraging meat consumption (lack of available prey or poisonous flesh) or other factors keeping population small. The latter could (for a writer) be a way to promote intelligence as a useful trait. Farming and selective breeding of the food will also promote this. Factor to keep population small include: predators, malnutrition due to a needed nutrient that isn't in animals, frequent devastating natural disaster which cover large areas, etc. My personal favorite at the moment is a limited amount of livable habitat. If there is little atmosphere protecting against solar radiation but the plants can survive this, the population will need natural caves to hid in during the day but will need access outside at night to feed. The few large predators (who eat meat as they never evolved a way to digest irradiated fruit without getting cancer) will likely attack entire dens at a time. The driving force for intelligent evolution and teamwork would be many fold. Farming, mining, defense, and den maintenance promote group survival and so they get smart enough to do that. Games during the long days promote education, communication, and cooperation so become encourages during the days. Those who are most intelligent win games, learn to dig instead of just harvest, and teach all keeping them inside away from cancer (or however the damage manifests) increasing lifespan and reproductive life. [Answer] I don't think a species must necessarily be hunters in order to evolve intelligence; that's just the way it happened on Earth, by chance. Hands didn't really evolve to throw spears--they evolved to swing through branches. All that is really required for intelligence to evolve is some way for a slightly more intelligent individual to survive slightly longer or breed slightly more prolifically than a less intelligent individual. In other words, intelligence will arise only in an environment where intelligence makes a difference. This usually takes the form of a competition, to be sure, but not necessarily a predator-prey type of competition. A smarter individual might find it easier to hide from predators, or to gather up more food, or to build a better shelter, or to remember and avoid hazards, or to learn from their own mistakes and the mistakes of others. There may be many paths to wisdom, and maybe not all of them are paved with blood. [Answer] You don't need to look far to find intelligent herbivores here on Earth. All of the great apes, humans closest relatives, are quite smart, and all of them mostly eat plants. Gorillas are entirely herbivorous. Orangutans eat mostly fruit, but will scavenge things like bird eggs if given the chance. Chimps and bonobos are known to hunt a little bit, but most of their diet is made up of plants. While predators do tend to be more intelligent then their prey that doesn't mean that all intelligent animals must be predators. A large brain doesn't impose a higher caloric or nutrient demand than a herbivorous diet can provide, just look at vegans. If you are interested in current theories as to how and why intelligence developed in humans you could start here: <https://en.wikipedia.org/wiki/Evolution_of_human_intelligence> [Answer] On Earth, intelligence correlates strongly with a couple of factors: 1. Meat eating (both carnivore and omnivore) >> herbivore & insectivore 2. Social living >> solitary living Of similar animals living in similar environments which display these traits, the ones with the above traits score higher in [intelligence (EQ) ratings](https://en.wikipedia.org/wiki/Encephalization_quotient). * Domestic Dogs > Domestic Cats * Lions > Tigers * etc. If you take predation "off the menu" for your planet's ecosystem, then you may need to rely upon social factors determining an animal's ability to mate. This could drive the population to higher intelligence, it might just take longer than it did on Earth. Alternatively, if you wished to drive many animal species to higher intelligence, make a planet with lots of sophisticated dangers. Only the animals with high intelligence or high birth rates create children able to survive the environment. [Answer] Elephants and parrots are basically sapient herbivores. I have no idea where elephants get the protein to develop such big brains but parrots get their protein from nuts, seeds, and certain fruits in the wild. The irregular distribution of fruits in forests and the need to remember where good food patches are is thought to have driven the development of their large brains (a similar process may have happened with primates). And unlike a lot of birds they don't really supplement their diet with a lot of other foods. Yes there are parrots like the kea and the Antipodes parakeet that do eat vertebrate flesh, and other will take insects, but most of their diet is fruit and nuts. [Answer] An animal that must "hunt" the plants that it eats would experience greater pressures towards developing greater intelligence than a grass eater. Remembering where and when to find the ripe fruit, or how to avoid the poisonous leaves to access the succulent berries, or how to subtly direct the herd of dumb (and much tastier appearing) grazers along the paths you wish to take to avoid the direct attentions of predators would all be of benefit. A low reproducing prey species would benefit from "out-smarting" the predators where a high reproducing species simply accepts the losses to predation. ]
[Question] [ Following my previous question, > > [A King can't go to war](https://worldbuilding.stackexchange.com/questions/18794/a-king-cant-go-to-war) > > > I decided that a power that could oppose a King was facilitated by having a religious component. The idea is to have one of the main land-owner, the local head of a Church, similar to [Prince-Bishop](https://en.wikipedia.org/wiki/Prince-Bishop#Holy_Roman_Empire) of the [Holy Roman Empire](https://en.wikipedia.org/wiki/Holy_roman_empire). Due to the land he controls within the Kingdom, he is one of main "Peer of the Kingdom", and as he is as well a key person in the religion of the country, he has ways to get the support of the local population, which amplifies his opposition to the King. Now, I am trying to build the said Church and Belief, but due to the examples I referenced above, only the Christian Church come to my mind. However, I don't want to make any statement or judgement on the Christian Faith at all within my story, so I'd like to design my Church not to be too identifiable with any existing Church. The easiest that come to me, and are quite common in Medieval Fantasy is to set a polytheist religion. Unfortunately, the examples I can think about are typical animist religions like the Norse, Celt or Shintoists religions, which were, to my knowledge, quite unorganised, and the typical Greek-Roman Gods. But there, one had to choose to be a priest of one or another God, and no God were really taking over the others. **Can a polytheist religion be organized in a similar way as Roman Catholic in the Middle-Ages, as far as its relation with power control is concerned?** To clarify a few points, you can see above, that I am interested in a Prince-Bishop-like figure who would hold considerable (open) political power as well as moral due to his position within a given religion. In principle, the Sevens' Faith from *A Song of Ice and Fire* is a bit in the direction that I would like to have, but GRR Martin hasn't been *always* lauded for the realism of his world. And I am not aware of any similar Cult/Religion existing or having existed in our World..? A note, stemming from one of the anwer, I am interested in a Church as a purely political organisation. That means that they have an influence in the population who believe almost entirely in the presence of some Gods. But I don't want said Gods to go around, strolling the land doing a few miracles here and there. [Answer] **Organization of Roman Catholicism** The leader of [Catholicism](https://en.wikipedia.org/wiki/Global_organisation_of_the_Catholic_Church) is the Pope, followed by cardinals, then archbishops, then bishops then priests. Authority is divided by geographic area at each level of the hierarchy, where higher positions have larger areas. **Polytheism in Catholicism** The Catholics claim strict monotheism though a brief reading of the their concept of Saints makes it easy to see how a polytheistic religion might maintain a large hierarchical structure *and* be polytheistic too. Catholics pray to God, the [Saints](http://www.catholic.org/saints/), Jesus and the Virgin Mary depending on a person's beliefs, upbringing or specific need (Saints usually have some specific jurisdiction. St. George is the patron saint of England.) **Strict Polytheism in a hierarchical religion** On the surface, it would appear easy to just state that a polytheistic religion would have a strict hierarchical organization but there are some problems. Monotheistic religions tend to have strict rules around getting into heaven and keeping God happy. [Polytheistic](http://www.polytheism.net) religions are more relativistic and less concerned with eternal rewards. It's possible to have many gods in a hierarchical religion but it takes a unifying core to maintain organizational cohesion. **Organizational Cohesion** If organizational cohesion doesn't come from veneration of a single diety then it must come from something else. A couple options are (but not limited to): ethnic cohesion, tribal cohesion, militaristic influences, cultural inertia, or belief in a charismatic leader. **Political Interactions** The Catholic Church managed to maintain a distinction between spiritual power and earthly political power. It kept absolute power over spiritual affairs till the Reformation broke its strangle hold. If this distinction doesn't hold then the king will see the religion as a competitor and take action to minimize the religion's power. In your world, as long as you can maintain a distinction between earthly and spiritual authority, then the religion can be monotheistic or polytheistic independent of a king. [Answer] Egyptian religion was: * Polytheist (except for 20-year aberration of heretical Aten worship) * Quite powerful and state-integrated, with the head of religion being pretty much 1-2 steps below the deity/Pharaoh. Seems to fit your requirements. [Answer] If you structure the polytheistic religion appropriately there's absolutely no reason you *couldn't* have a "poly-pope". In many of the theologies you've listed there is a "king" of the gods (Odin, Jupiter/Zeus), and it's a pretty easy handwave to have the prince-bishop say "the King of the gods is the only one who we can talk to, and I'm his representative". Add in a few thousand years of church infighting resulting in the Prince-Bishop being all powerful and you have your powerful polytheistic church :) [Answer] If you want division of power with polytheism, I suggest studying the history and religion of Sparta. Sparta invented the division of powers in government. They had a complex interaction of different focuses of worship with a large set of holidays, rituals and required consultations clearly intended to keep either of the Spartan kings or anyone else from getting to much centralized power. It's not much of stretch to see the same system spread over several kingdoms. [Answer] The neo-Paganism that the feckless Emperor Julian the Apostate wanted to create was just about exactly what you want. He was trying to replace Christianity with a Pagan equivalent and wanted to create just such a hierarchy. He was killed in battle before much could come of it, and has been a subject of what ifs by College Sophomores ever since. I think that even without his death, his aims would have been thwarted by pagans themselves. His imposed rank ordering of gods was just as alien as Christianity to them. [Answer] I would have an **Ascendant Priest/God** at any one time. So for a very simplistic example, let's say you had, *very roughly speaking*, five gods, each representing primarily the following: * War * Love * Farming * Travel * Bananas The major priest of each of these gods would make up a conclave, and from those they would select a central figure - your Pope-Prince - who would then represent the polytheistic church and wield temporal power. You could have this figure rotate for multiple ways. "For Life" is probably the must unlikely. I think the most common two would either be electing a Pope-Prince for a set term (5-10 years), after which that god can't repeat, or rotating through the gods, so you always go War -> Bananas -> Travel -> Farming -> Love -> War, for example. In addition, it might be possible for the conclave to meet and remove the Pope-Princess from her position and replace her with another cardinal-level person from the same church. This allows your church to have a centralized figure, while still over time representing all gods of the church. [Answer] The way I understand your requirements, you want a polytheist structure that can oppose a king but that does not completly dominate him. (He needs to be able to "beat" the church opposing him without having to destroy it, which could be a problem with the Egyptian religion). The roleplaying game DSA (Das schwarze Auge - translated: The black eye) has a polytheist structure you might find a good inspiration. There you have 12 main gods (ok, 13 but that's a story for an other day) that all embody different traits (Rondra is the godess of war and honorable combat, Phex is the god of merchants and thiefs, Hesinde the god of knowledge and mages and so on). Chief among them is the god Praios who embodies Law, order, righteousness. (There are also many minor gods who are mostly the children of 12 main gods). There is quite a lot of conflict between the gods (Phex wants to steal everything there is and put it up on the night sky as stars, Praios wants people to obey the law and hence not steal...) They are siblings and as such can be played against each other, but when the shit hits the fan they will set their squabeling asside and band together. Most of the time the local heads of the churches do not intervene much in the political decisions. But when they do, their words have a lot of weight and can not easily be dismissed. Hence, when your King wants to start a war, he definitly needs to get the head of the Rondra church on his side and for that, the war has to have an honorable reason, so your King needs to fabricate one. Be carefull however: The gods are very active within the country, so it is close to impossible to find a head priest who only "belives for show" and hence can easily be bought. True miracles are "normal" but rare. Example: The god Effered is the god of water and the sea. He might grant his priests the ablitiy to walk on water. (btw: recently the creators of DSA started to publish books containing liturgys of the gods. It is also possible to play as a priest so there are quite a lot of rules and additional information about the pantheon available - From the way an acolyte is accepted and raises through the ranks, what the temples normaly look like inside and out, all the way to the miracles a god might grant and why. I am just not so sure, that all of it has been translated to english yet) ]
[Question] [ As a more detailed follow up question to my earlier one ( [Which types of firearms would be damaged or broken by a global change in combustion intensity?](https://worldbuilding.stackexchange.com/questions/9232/which-types-of-firearms-would-be-damaged-or-broken-by-a-global-change-in-combust) ) There is new magic entering the world(approximately present day tech level or higher) that allows for a number of fantasy-like spells to be cast. This magic works by a person using their "Life energy" to pierce a dimensional barrier, and draw energy from a parallel "Magic" Dimension to cast a spell. As the barriers between dimensions are pierced more often, background magic energy dissipates into our dimension. One of the side effects of this background magic energy is that it disrupts detailed electronics as well as some types of combustibles and explosives. Computers, firearms, and many types of advanced technology no longer work properly. Living entities are not impacted by these effects because their "Life energy" passively nullifies the reality altering side effects of magic background energy. The effect is localized to the areas where magic is used often. The effects are subtle enough that they don't disrupt large scale geological activities. With all of the background details taken care of, the actual question: What would be a way for this to be explained without too much abuse of logic or scientific law? What specific changes would this magic background radiation need to alter to get the desired effects of nullified technology, with the smallest number of other side effects? I'd like to have a better explanation for these side effects than just saying 'Because magic'. [Answer] > > There is new magic entering the world(approximately present day tech level or higher) that allows for a number of fantasy-like spells to be cast. This magic works by a person using their "Life energy" to pierce a dimensional barrier, and draw energy from a parallel "Magic" Dimension to cast a spell. As the barriers between dimensions are pierced more often, background magic energy dissipates into our dimension. > > > Ok. So we already have a basis for people using magic energy to create effects. What if having background magic means that people use it subconsciously? Let's say that everyone has at least some ability to manipulate magic. And unless they're explicitly trained to control their thoughts, this ends up being expressed as a small, low-level modification of probabilities around them. For the most part, this is neutral. The universe doesn't really care if a specific electron goes left instead of right. But in computers, this tends to result in occasional extreme power surges, and ones that tend to bypass most protections (because they occur **directly** in the delicate software). So computers are actually fine most of the time, but if they're on while someone is near them, they tend to break in a couple of hours. A couple of additional implications of this explanation: 1. People would probably be able to influence chance events without realizing it, if they're happening right in front of them. This would have obvious impacts at say, a casino. It wouldn't be a guarantee - it doesn't mean you'll always end up hitting a 7 if that's what you really want in craps - but it would increase the probability of it happening. This effect wouldn't apply to card games (since it's unlikely someone would have enough knowledge to impact shuffling the deck), but dice games and roulette would get interesting. Another less-obvious impact would be sporting events - what happens when you have several million people who really, really want the guy to catch it, and another several million who really, really want him to drop it? 2. A specially trained operator who meditates and orders their thoughts could probably still use computers. By the same token, a computer system that was isolated from humans could still operate. So this leaves room for some computer use, but nothing like our current day-to-day. [Answer] The best explanation I've seen for this sort of thing is from the computer game "Arcanum" which has magic and tech factions in conflict. Paraphrased: "Magic works by causing physical laws to randomly fluctuate in useful ways. Picture putting a block on an inclined plane, so that friction provides just enough force to keep the block in place. Now, bring a magic item of any kind near this plane. The item will make forces vary slightly, including the coefficient of friction for the block, so the block will now randomly start sliding every so often." If there's an effect like this, then the more complex the machine, the more kinds of physics are likely to go wrong. See also the Harry Dresden novels, in which Harry's tendency to jinx machinery makes him unable to use a semi-auto pistol but he can still use a revolver, whose mechanism is simpler. So, you can justify the general idea that "complex machines don't work around magic" or (slightly different) "complex machines spontaneously break even if they're off, near magic". If you want a more specialized effect in terms of breaking specific physical laws, think about your magic radiation as being from some other universe that has its own physics that still apply to it. That's basically what I used in a story to say "there's a zone where deadly weird stuff happens, and outside that zone magic interacts with this and this kind of material to do X." If you want to talk about specific laws to break, good things to look at would be density of materials (making critical pipes/airtight seals leaky) or the energy involved in the various orbitals of an atom. Eg. the Challenger exploded because of three leaky gaskets letting fuel out of where it should've been. Many of the properties of water come from the shape of its orbitals, which make the molecule polar, so playing with an effect like that could justify a whole lot of chemical reactions not working right. Messing with electrons' behavior can break electronics too, or justify fancy alloys or plastics rapidly breaking down. A cool possible side effect of this thinking is... aw, someone suggested it already, but imagine equipment being made of living wood &c. to protect it. [Answer] I can think of things that would cause initial problems, magic fields could chaotically induce currents and voltage spikes, produce erratic bursts of radio waves and microwaves ( at semi-random points anywhere throughout the field so it could happen inside any shielding). But no particular effect is going to be a permanent barrier. Electronics will be made that are hardened to such interference. If living tissue blocks the effects then people will start embedding chips in living wood or coating boards with slime molds. People are attached to their technology and they're not going to give up on it just because it becomes harder. While your mages are throwing fireballs there will be geeks working out workarounds and developing ways to generate power from the effects of the background magical field even if it takes [4 cc of mouse blood or even a fresh egg and two small sticks.](http://essential-terry-pratchett-quotes.tumblr.com/post/54697106456/the-rite-of-ashkente-quite-simply-summons-and) The harder problem is people. If you want to totally nullify technology then your magical field would actually have to make people disinterested in technology or affect their knowledge of it or **somehow apply group punishments to those who use it**. If magical fires or deadly magical plants and beasts start attacking people anywhere that people use technology inside a magical field then you'd start getting mobs hunting the geeks unwise enough to tinker with electricity/computers thus bringing death and destruction to their neighbors. Which could be fun: angry mobs in half the world trying to keep the magical fields at bay by hunting down witches before they can contaminate the local area while in the other half mobs hunt geeks for fear that they'll [call down judgement]/[disrupt the local magical flows]/[attract the magical beasts to the village]. [Answer] During WWII, magical beings known as "Gremlins" were invented as the cause of various otherwise inexplicable failures in mechanical devices and war machines. If your magic universe supports some form of life, they could instantiate on Earth as Gremlins and live here by eating or otherwise disrupting technology in various ways (those key gremlins are the worst, stealing key rings for reasons that only make sense to them...). If they feed of electrical energy, then electrical devices will suffer from voltage spikes and fluctuating current whenever a flock of these things happens to be nearby feeding. You can tailor the effects to support the story, so long as they are reasonably consistent (Gremlins won't be able to feed off electrical energy *and* doughnuts, for example). [Answer] To answer the question, ***What would this background radiation need to alter to nullify technology with the smallest number of other side effects***, you'll need the magic energy to present as some form of constant Electromagnetic Pulse... This would disable electronic technology effectively enough, with minimal side effects to biology or geology... However, the main problem you'll still have in this scenario are explosives and combustibles. (I imagine you want motor vehicles to not work anymore?) In order for that to happen, you'd need to change the way some basic chemical interactions happen, setting a cap on the rate and pressure at which certain fuels burn, at least, in an area of space local to Earth. Determining a mechanism for that may be a bit more tough... Perhaps you could chalk it up to dimensional instability? ]
[Question] [ The basis of known life on Earth is water, clear and simple. But what about forms of life on other worlds? Not every world in the universe is as hospitable as the Earth. Suppose a planet had an average temperature slightly higher than the melting point of iron: 2,800° Fahrenheit (1,538° Celsius). On this world, there is roughly the same landmass-to-liquid ratio as Earth, except the liquid here is iron. Ignoring the plausibility factor of life naturally appearing in such an environment, what would native flora and fauna look like? What adaptations might they have for existing in such an unearthly world? [Answer] **Floating plants.** Molten Iron is hot. When I think of all this molten iron and high temperature, it reminds me of hot air balloons. Hot air rises. Consider a plant that bobs up and down on the heat generated by the surface of your world. It bobs because it opens and closes the bottom of itself. When it's up high, it fills itself with cold air. When it drops down, it releases this cold air around it so that the hot air underneath it will push it upwards. It will never touch the molten iron, but it's constantly provided with lift. It's likely to actually look a bit like an ball , or kind of like a spherical parachute (Actually, it's probably going to pulse like a lung too). It's able to take this lift, and stay safe from the molten iron, while being able to photosynthesize in the air. Perhaps you want something bigger. What if these plants grew in clumps? Now you have cloud sized floating plants. **But what if we don't want to be in the air all the time?** Is there any way it can survive on the land? Since we know the liquid is the melting point of iron, lets take the land to be of element x, with some melting point higher than iron. As noted in the comments of the question, the landmass is Tungsten. These plants would likely burn up instantly that close to the surface - unless they were made of something with a higher melting point, such as Carbon, or palladium. What if there were plants that self coated themselves with these elements? We're probably going to have to hand wave the internal cooling and nutrient transport systems, but lets say there's an element y in liquid form that doesn't boil at the planet's temperatures. They might be able to survive, although on a world described as such, photosynthesis is unlikely at the surface. Instead, they may turn to using geothermal energy.. [Answer] **The answer:** I don't know of any chemical system that can maintain the complexity necessary for life at the temperatures you cited (~1,600 C). **Alternatives:** However, a variety of scientists have considered what other chemical systems life might use to cope with different temperature regimes. [This reference provides a list of those thoughts along with relevant temperature ranges and other notes of interest:](http://www.projectrho.com/public_html/rocket/aliens.php#id--Alien_Biology--Building_Blocks) I reproduced a table from that site here: $$\begin{array}{c|c|} \text{Temp Range} & \text{Macromolecule in Solvent} \\ \hline \text{400° C to 500°? C} & \text{Fluorosilicones in Fluorosilicones} \\ \hline \text{113° C to 445° C } & \text{Fluorocarbons in molten Sulfur} \\ \hline \text{0° C to 100° C} & \text{Proteins in Water} \\ \hline \text{-77.7° C to -33.4° C} & \text{Proteins in Liquid Ammonia} \\ \hline \text{-183.6° C to -161.6° C} & \text{Lipids in Liquid Methane} \\ \hline \text{-253° C to -240° C} & \text{Lipids in Liquid Hydrogen} \\ \hline \end{array}$$ **A matter of perspective:** To life evolved on a Methane world and using the lipid - liquid methane system, our (Earthly) life would look like a world of "molten rock" (aka water) and we would look like beings made of liquid rock. To us, beings using the fluorosilicones in fluorosilicone chemical system would look like beings of molten rock too. [Answer] Molten iron is probably far too hot for this to work (even computerized robotic beings would have their silicon brains melt), but perhaps if you restate the idea for a world of molten sulphur like Io in orbit around Jupiter. Sulphur melts at a much more modest 388.36 K ​(115.21 °C), so oceans of liquid sulphur could indeed exist on a world with the usual silicate mineral shell surrounding an iron core. Sulphur is also an important ingredient in many biological systems, along with phosphates, so while a life form might not actually live in the sulphuric ocean, life forms might take advantage of the sulphur vapours or the constant rain of sulphur oxides in order to get the elemental sulphur needed to sustain biological processes. A moon like Io is also immersed in Jupiter's powerful magnetosphere, so the sulphur thrown into the atmosphere by volcanic eruptions (or sulphur vapours boiling out of the oceans) could become energized . Life might be powered by electrochemical reactions driven by the availability of ionized sulphur in the atmosphere, a weird sort of analogue to the sulphur driven creatures living by deep ocean thermal vents here on Earth. Obviously, these creatures wold need some sort of "feeding" mechanism, perhaps feathery protrusions to collect charged sulphur ions to drive the electrical system, and a "ground" trailing behind or below to control or bleed off excessive charge. Electrical energy would be stored in the biological equivalent of a battery or capacitor. The ecosystem of such an electrical world would be very strange (predation wold consist of stealing or draining the charge from another creature). The creatures wold also have senses built around the massive electrical, magnetic and radiation fields of Jupiter (or the primary planet, if we are talking about an alien solar system), and live in an environment where "snow" is elemental sulphur condensing out of the atmosphere.... [Answer] For the planet to be that hot, 2800° fahrenheight, the planet would have to be rediculously close to the star that it is orbiting. A good example would be a 'hot jupiter'. Due to its closeness to the star, the planet would be tidally locked, meaning that one half is allways facing the sun. This means that there is a drastic change in temperatures from one side of the planet to the other. While one side may be 1600° celsius, the other may only be 500° celsius. All of these properties create some crazy weather like winds that travels over the planets surface at thousands of miles per hour. Though the weather on such a planet would be so harsh I doubt anything could live there, this puts the temperature of the dark side of the planet within the temperature range that life form of a Fluorosilicones chemical system (from jim2B answer) could "survive". It is thought that on such planets that the auroras that only occur at the poles on earth would occur all over the planet, which would be an amazing sight. The clouds would be made up of things that seem ridicoulous to us like metal, silicate and rock. It possible that it could rain metal, glass and other things. ]
[Question] [ *There is a TLDR section below for those who don't want to read the dialogue* „So, what is magic?“, young Fineos asked. „Well“, said Rhabea, trying to buy herself some time. „Magic is a lot of things.“ – „Yes, I know, but how does it work?“ – „It works in a lot of very different ways. There is not just one kind of magic.“ She knew what the other adult mages think of her and about her qualification as a mentor. „There are, at least, three different forms of magic I will tell you about, whilst we are together trying to make a mage out of you who will not kill himself out of stupidity.“ Sometimes, she thought they were right. „There is the Elwin’s Living Magic that can grow by itself. Then, there is the summoning magic sorcerers use, which needs quite some physical commitment to do its things.“ Rhabea was not sure if she understood the following part as much as she should, considering that she is about to *teach* someone to use difficult and dangerous things. „And then, there is the magic we can use. But even our magic doesn’t just work in one way. Nonetheless, we will focus on one way for today. Everything in our world is composed of tiny pieces we call atoms. They are composed of even smaller things, but you will understand this better when you actually learn how to cast magic. Also, there are two kinds of magical energy in our world. One is everywhere around us. It seems like it's just flowing around and through everything. The other one is in us mages. That is what makes us different from peasants and kings alike.“ This took really long for her to get when she heard it first. „While the energy around us never seems to deplete, whenever you use your magical abilities your own energy will leave your body. To renew your magical energy you need to meditate or sleep. I will show that to you later on.“ It will take hours until she sees the essentials she forgot to tell the boy. „Now listen, this is really important. I will tell you how you can alter the world.“ For her it was always something she *feels* more than *knowing* or *understanding* it. „You can guide your magic out of your body. It will flow like a small river, always connected to you. Intuitively, you can let it out through your fingertips, but really every part of your body works equally. If, in the future, you will be more experienced,“ she never was, „you can guide it with your mind. But, also, using your fingers will help you a lot to get the hang of it. Now comes the hard part: With your magic, you can influence the magical energies of the world I talked about before. You can *convince* these energies to alter the atoms of objects and thus altering the objects themselves. You could make air more flammable or water to wine or even gold out of iron.“ – Fineos got quite an interested look on his face. „So why aren’t all mages rich and have castles out of gold?“ – She knew this question would come. It was one of her first questions, as well. „Because nature knows better what nature should be.“ Also, castles made of gold are typically not that stable and are prone to attract unwanted attention. „As soon as you stop fueling your spell with your energy, something known as **natural balance** will start to set it, reversing what you did as good as possible.“ Which killed or crippled more than one stupid mage who forgot about this rule. „Think about it like cooking soup. The soup is the object you want to alter, the fire is the magic of the world and the logs are your own energy. Without some wood the fire would instantly go out. But even then it would take a while until your soup is cold again.“ Fineos seemed lost in his thoughts for a few moments before he asked: „What about altering people? ... I mean, for healing purposes for example.“ That wasn’t his first thought and she knew it. But there was no need for lying to him. „In short: you can’t. We don’t really know why, but the human body seems to have a natural defense against intruding magical energies. But there is a way. If the recipient actively *wants* to let your magic flow into his body, you can do whatever ‚healing purposes‘ you have in mind. Though, at the moment he loses his trust in you, or his consciousness, your spell will got cut off and start to fade.“ The boy nodded absentminded trying to figure out the possibilities of his power. --- Now, before I let you empathize with Fineos, consider a few things regarding **the setting**: * It’s an earth-like medieval-tech fantasy world (because creatively has really small borders for me) * My physics and chemistry levels are as low as mowed grass, so there is a high possibility that this idea might be really stupid; if so, please point it out * Mages are pretty rare; it’s probably genetic and often comes with physical or mental disabilities (which leads to even fewer mages getting old enough to be mages, and stigmatises magical abilities for the general public) * For your magic to have a visible effect you need to change quite a few atoms; this will take time (I don’t have a formula at the moment) but as you will get more experience you will be faster at altering the world, too * Since this magic is based on atomic structures changing an atom to one close to it on the periodic table should be faster than changing it to one far away; that means changing gold to platinum (or even silver for that matter) should be generally easier and faster than changing it to iron, or vice versa **TLDR:** There are two magical energies: one in the world around you, one in den mage itself. The own magic is some kind of catalyst for the world‘s energy. The world‘s energy consists of some sort of [Ditto](http://bulbapedia.bulbagarden.net/wiki/Ditto_%28Pok%C3%A9mon%29#Pok.C3.A9dex_entries_2) or stem cell atoms or maybe just protons and electrons (as said, I only know vaguely what I’m talking about). As a mage you can use those pink Ditto atoms to change the atoms of the desired object to whatever you like (with appropriate amount of Dittos and your own energy). When you cut your connection to the object, mother nature wakes up and starts to clean the mess you made to its natural state (if possible). Humans‘ (and possibly other animals‘) atoms can not be altered in any way, unless they want you to. **My Question:** Can a magic system, as described above, work in said setting without breaking laws of physics or even breaking significantly more than pure physical strength could do? For example, it would be possible to alter parts of a stone pillar to something gaseous in room temperature, let it spread, then break the spell. In this way, the pillar could collapse due to its now missing parts. But this would be also possible for some beefy guy with a hammer. But I think to do the same with a mountain should be quite impossible (at least in a lifetime). **For Reference:** The idea to this magic was sparked by [Fullmetal Alchemist’s transmutation](http://fma.wikia.com/wiki/Alchemy), but I think that was far too powerful and its theoretical restrictions felt more like loose guidelines to me. [Answer] If you're going for as much scientific realism in your magic as possible (which seems to be the case), you need to be crystal clear about how atoms are being manipulated. As the comments in HDE's answer point out, there is a very big difference in the result of a spell that *creates* particles and one that *rearranges* them, given your world's condition that things attempt to revert to their previous state. I draw the following conclusion's from your explanation: **1. Magic is in everything and everyone, even though only mages can consciously control it.** The existence of the "natural balance" combined with magic's ineffectiveness on humans unless they are willing suggests one of two things: Either everything that exists does so at a stable "balance point," which using magic alters, and all humans possess a passive magical ability that keeps their own states from being altered unless they consciously allow it; or else will is an intrinsic part of magic, and humans are normally immune because their wills generate a natural magical field (which disappears if they want it to, even if they don't understand that that's what they want) and that *nature (or some omnipresent force) has a will, although a mild/slow-acting one.* In the latter explanation, your dittos are essentially will particles, a sort of conceptual hybrid between philotes in Ender's Game and a Green Lantern. **2. Magic's effectiveness is directly related to the laws of chemistry.** You said yourself that a spell that changes fewer atomic particles is easier. If we also assume that it is easier to create something from nothing than it is to rearrange an existing atomic structure (because rule 1 applies only to existing matter, and it is generally easier to create things that will quickly fall apart than those that will last), we can already break spells down into two major categories: Lower-level spells rely on magic to create objects, and are easier to perform, but the objects the create vanish immediately. How effective these types of spells would be against humans is tricky. A mage should *not* be able to wound a human with a conjured blade, but he *should* be able to cut a rope a person is climbing with one, perhaps causing them to fall to their death. Higher level spells are harder, more so as the area affected grows, but are as permanent as if they would be if they were naturally occurring. In other words, if you move the particles around to a new balance point (i.e. anything that can exist naturally), it will stay there; if not, it will fall apart. This means that the best mages will have knowledge of chemistry. Likely they would carry pouches of various finely ground metals, which they could use to make more advanced spells balance easier. In short, a mage is simply a chemist with a very powerful tool for manipulating reactions, and knowledge is literally power to him. Think MacGyver with a pointy hat. **3. A truly great mage could turn a willing human into a mage.** If magic ability is genetic, there are physical protein sequences which control it, which magic could alter. This would be one hell of a spell, the stuff of legend that perhaps no one alive could do, but it would be possible. A more common ability would be to modify the DNA of a newly conceived embryo so that it is born a mage (or isn't). A mage with this skill could also prevent his offspring from having any of the disabilities that often afflict them. **4. Advanced mages could have unnatural healing abilities, and perhaps even immortality.** A mage should be perfectly willing to heal himself, and would do so if possible. You can decide if this is possible or not. Either it isn't, because even magical forces must act on other objects, not themselves (which is why you can't pick yourself up off the ground and levitate); or it is, because the magical and physical worlds are distinct enough that the former scenario would not be a violation. Even if a mage couldn't heal himself, a pair of mages who trust each other could keep each other alive a very long time. [Answer] I think that we have to accept that the concept as a whole breaks some physical laws, simply because it's magic. You can't easily come up with a plausible scientific explanation for how it works. I admire the planning, thoroughness, and - to a decent extent - realism of your idea, but, as I think you know, we have to admit that some laws of physics go down the drain when we use this magic. There's only one other thing I can find a hole in with the idea, and that's based on one passage (emphasis yours): > > „As soon as you stop fueling your spell with your energy, something known as **natural balance** will start to set it, reversing what you did as good as possible.“ . . . Think about it like cooking soup. The soup is the object you want to alter, the fire is the magic of the world and the logs are your own energy. Without some wood the fire would instantly go out. But even then it would take a while until your soup is cold again.“ > > > The one thing I see here is that the analogy is poor. Let's say that you instantly take the soup somewhere else, in a perfect vacuum isolated from every other thing in the universe. The soup will retain its heat. Why? Because there's no place for the heat to go. On the other hand, if you keep the soup where it is, it will cool down, because it is hotter than its environment, and heat energy flows from hotter things to cooler things. On the other hand, take an example you gave about turning an atom of one element into an atom of another element. For simplicity's sake, Let's say that you have a hydrogen atom with two neutrons. This is called [tritium](http://en.wikipedia.org/wiki/Tritium), an [isotope](http://en.wikipedia.org/wiki/Isotope) of hydrogen1 Tritium is radioactive, but that's besides the point, because not all the atoms in a sample of tritium will instantly decay.2 Say you add a proton to an atom of tritium. You now have an atom of helium-4, which is nearly identical to an [alpha particle](http://en.wikipedia.org/wiki/Alpha_particle), with the addition of two electrons. Helium-4 is stable. It will not radioactively decay back to tritium and a proton.3 This is the main problem I see with your magical setup. Are there other things? Sure. But they can be explained with magic. This one thing - the idea that the system will go back to its original state once magic is no longer applied - is one of the things that makes your great idea distinct from other magical systems, and it is the one important thing that goes against the laws of nature. --- 1 An isotope of an element has the same number of protons as all other isotopes of the element but has a different number of neutrons. 2 That's the idea of a [half-life](http://en.wikipedia.org/wiki/Half-life): Only *half* of the atoms of a radioactive element will decay within a certain timeframe. Let the same amount of time pass again, and only one quarter of the original number of atoms will remain, etc. 3 We really should have added an electron along with the proton to tritium to produce helium-4; otherwise, the atom would be an ion and not electrically neutral. Thus, the helium-4 atom would go back to a tritium atom, a proton, and an electron - if your idea worked. [Answer] You may want to look up the movie [The Sorcerer's Apprentice](https://en.wikipedia.org/wiki/The_Sorcerer%27s_Apprentice_%282010_film%29). There the mages do magic by controlling the very atoms of everything (not with dittos like you explained but similar in a way nonetheless). As for implications, if there few mages they would probably all be killed by the majority of scared normals. Unless they are really really strong or just an accepted part of society. I also believe that one mage putting up a defensive barrier could be easily out-transmutated by a stronger mage. If the stronger mage uses his ditto force to alter the very ditto force of the defending mage, his defence will vanish along with it. Secondly if they are altering atoms themselves it can become easy to kill humans (and animals) even without having 'access' to their inner atoms. Just make the whiffs of air in front of their mouth toxic. this doesn't even have to be a really efficient toxin, just making the air they breed thinner or heavier on CO2 will suffocate them, especially during war time when one breaths more often. [Answer] Any form of magic would per definitionem breaks the laws of the physics is some way, since magic is the ability to cause scientifically unexplainable effect with your own intention. (Not asking a divine being to do so, since it would be a miracle. ) But you may decide to preserve some fundamental principles and concepts. Lets start with the conservation laws. These can be used to draw a well defined line between possible and impossible: 1.) Conservation of energy. Since the special relativity kicks out absolute simultaneity, this should be formulated locally: The the change in the energy (magical and non-magical) content of a volume equals the energy flowing through its surface. This contradicts Rhabea's quote: „While the energy around us never seems to deplete" . But, if the magical energy in the world is astronomically high, the changes in it by the mages would be negligible. 2.) Conservation of momentum. This would force you to accelerate some mass in the opposite direction, while accelerating something. Causes extra energy to be wasted, but otherwise not too much trouble. 3.) (Local) conservation of electric charge. The the change in the charge content of a volume equals the current flowing through its surface. This allows the creation of positively charged objects (particles, bigger objects) only, if something with the same negative charge is created right there. 4.) Conservation of barion and lepton numbers. These laws allows the creation of 'matter' (in the meaning of objects composed from barions and leptons, eg. atoms.) if the same amount of antimatter are created. And vice versa: you can only destroy matter into energy, if you destroy antimatter too. (annihilation) You could preserve the theory of relativity too. This would surely cause interesting consequences, witch I cannot cover fully, but assuredly it would require the Laws of Magic to be invariant against Lorentz-transformation. It would mean too, that mass is connected to all magical energy too. You might include the Heisenberg uncertainty principles. These would mean a theoretical lower limit to the size of the things, which can be manipulated with magic. A quite exciting quantum-magic would come to existence, but serious calculations would be necessary to determine, whether this would render subatomic magic ineffective, or not. So, it might be wiser to drop this idea. I have mentioned the Laws of Magic before. This (at least from the in-universe scientist) would require a significant effort to create. Since the magical energies can be controlled directly by one persons mind, spirit, soul or will or whatsoever, so traditional mathematical apparatus and physical concepts, like particles, vector and tensor fields, forces and interactions, waves, functions and operators... would be insufficient. They (in universe theorist) would have to develop theoretical models and mathematical concepts to describe willpower, spirit and consciousness. What would be this all useful for? Subatomic magic is not to be used on macroscopic objects, which can be manipulated pretty good by conventional means. Mages should focus their minds on the nano and picometer scale. They could create impressive nanotechnology, easily perform genetic modifications, create metamaterials with unusual properties, or even make exotic mater. (Containing antimatter in bound state, strangelets, or degenerate matter...) The possibilities are almost endless. ]
[Question] [ **Communicating using the sun:** Frontinus, while studying the Greek classics, invented a system of communication based on towers, mirrors, and shutting aparatuses that could communicate along Roman empire by means of light rays (day only). Using something similar to a morse code, operators positioned in towers along a route, distant 20 by 20 km, could deliver messages from all over the empire in a lightning quick speed. ![heliograph network](https://i.stack.imgur.com/km5FG.png) **Question:** What would be the consequences for the empire? Could this help alleviate the incoming barbarian invasions? Could this free legions to be used in more massive attacks against Rome enemies? How this could effect Roman commerce? [Answer] A semaphore system would have great logistical advantages, in that supplies could be ordered with a reduced lead time, meaning that with vital supplies that cannot be allowed to run out, less stock need be kept on hand, as the reduced lead time reduces the safety levels that must be maintained. As a consequence, warehouses could be smaller. However, the military implications, while not negligible, would not be all that great either. It would allow the military to maintain fewer, larger garrisons since there would be some additional lead time to respond to an incursion, and would also free up some soldiers as the number of men required to respond to an incursion would remain the same, while the garrison force would be effectively reduced. However, given the low travel speeds of a roman army on land, the differences would be that garrisons would need to be placed , say, 8 hours march apart rather than 6, as the communication lag is much lower. The difference between 8 hours march and 6 is around 10km at most. [Answer] The empire was definitely well spread out enough that this could have had a decent impact in a couple aspects... Military: The Western Roman Empire that broke off from the Eastern Empire was pretty well doomed and this invention wouldn't have saved them. That said...it would have helped due to their setup. The Roman army was divided into two types of forces. The first was the Limitanei. These were Roman citizens that lived in Frontier towns for their lives. The would frequently marry women from these frontier towns and become part of the town and people...raising their families et al. They weren't exactly the best equipped, but they could defend their town as required. Once a frontier town was attacked, the Roman garrison would send word to the second line of Roman defence. The second line of defence were Comitatenses...this was the professional Roman army that was designed for quick deployment using their well created road systems. The Limitanei would hold their ground defending a towns walls while they waited for the Comitatenses to ride in and break the seige. Quite effective in that one army could effectively garrison multiple frontier towns. The impact in this sense would be extremely beneficial...the time that it took a Limitanei force to report the attack on them and the Comitatenses to start on their way would be minimal compared to what it took to dispatch a messenger instead...it would really make this tactic that much more effective. Would it have stopped the Barbarian invasion? Unfortunately it's highly doubtful, the empire was heavily dependent on disappearing farming income and was pretty close to completely broke. Facing this broke military was entire tribes of people that uprooted themselves and marched their entire towns into Roman territory, in some cases sacking Rome a long the way. The Vandals marched through Europe and into spain, across into Africa, before settling into former Carthage (and sacked Rome from the south before being defeated by Byzantine). The Visigoths took up shop in italy after sacking Rome...the Franks moved into whats now France...the Lombardi people moved into Milan...the Huns came a long with. It's a long list, the Romans, even with near instant communication, couldn't resist this onslaught. If they had held onto France and the former Celtic territories, odds were they'd be facing a viking invasion as well. Roman power struggles didn't help much...an Eastern empire under Constantine started making deals where he just gave Western empire land away to the new tribes (franks in particular) and the will to maintain a Western empire pretty much disappeared. Economics: The Western Roman Empire was cash strapped...and unfortunately this setup would cost a significant amount of money to build and maintain. Nearing the end of their demise, they were actively disbanding troops they couldn't afford to pay. The Eastern empire would have had a decent go with the technology...messages from Constantinople over to Egypt would be quite quick. I'm not sure how this would translate into economic advantages though. [Answer] There would be some military advantage, but primarily the advantage would be in economics and possibly in some sense social cohesion. Having news of what was happening in Spain or Constantinople or Alexandria or anywhere else in the empire from anywhere else in the empire would make those places seem closer and would allow decisions to made with better information. Knowing about a ship that didn't make port as soon as it didn't make port gives one information that would otherwise take quite some time to get back so that deciding if and where pirates may be located becomes easier, allowing for more reliable commerce to occur, as well as shipping to be routed in alternative directions. This certainly doesn't solve the problems of the empire; it wouldn't prevent the barbarian invasion; it could possibly offset the cost of building and maintaining itself, but without social and governmental reforms in the end it just changes how much the Eastern Empire holds onto vs. how much the barbarians take. ]
[Question] [ I remember seeing a show on the Science or Discovery channel about a certain type of star, maybe a [magnetar](http://en.wikipedia.org/wiki/Magnetar), with a powerful magnetic field that would twist and wind over time. Eventually, the field would "snap", returning to a stable state and unleashing a wave of energy in the process. While the magnetic field around a magnetar is so powerful [it disrupts the electron cloud of nearby atoms](http://en.wikipedia.org/wiki/Magnetar#Magnetic_field), would it be possible to scale this effect down to a weapon capable of being used by a single human? Would such a weapon require so much energy for each firing it could only be used once, like an [RPG](http://en.wikipedia.org/wiki/Rocket-propelled_grenade), or would the weapon be useable repeatedly (albeit with a recharge/charge time), such as an [AK-47](http://en.wikipedia.org/wiki/AK-47)? What effects would the weapon have on the target, the user, and the surrounding environment (e.g., structures, bystanders)? Feel free to use any level of technology we can currently theorize in your answer. Edit: Some weapons, such as the railgun, are an impressive next-generation technology, but remain an embodiment of what has made mankind the dominant species on Earth: a "rock" thrower. I am looking for something beyond the next generation of "rock" throwers. Plus, purely energy-based weapons are much more powerful and fun to watch the destruction of. [Answer] Wow, $10^8$ to $10^{11}$ tesla. That's a dense magnetic field. If you want to weaponize this you might be making an electromagnet. We can calculate the requirements to build it. Here is the equation to calculate the magnetic field produced by an electromagnet: $$B = {{NI\mu}\over{L}}$$ Where $N$ is the number of turns around the core, $I$ is the current through the turns, $\mu$ is the permeability of the core, and $L$ is the flux path. It's good that you're allowing for any level of technology, because you'll need ridiculous amounts of current, it will have to be in a superconductor. The second magic material you'll need is one with incredibly high [magnetic permeability](https://en.wikipedia.org/wiki/Permeability_(electromagnetism)). Basically, this value defines the maximum magnetic field that the material can support. To greatly simplify it, Teslas measure magnetic flux density and materials have a maximum number of flux lines per unit area. I can't give you any ideas on what material to use, permeability changes with the magnetic field strength, it's nonlinear. We don't have data for regular materials with that high of a permeability, maybe they'll figure this out in the future. You'll also want to have some pretty significant protection if you're trying use this as a handheld weapon. Magnetic fields aren't lasers, they are closed loops. The magnetic field this is putting off is strong enough to rip you apart. That would happen [while you're levitating](https://physics.stackexchange.com/questions/61679/effects-of-a-very-large-magnetic-field-on-the-human-body) and your [brain is filled with light and sound](https://en.wikipedia.org/wiki/Transcranial_magnetic_stimulation). Shielding yourself from the weapon would require the same magic-core material, the one with incredibly high permeability. You can't block magnetic fields, you can only redirect them. So the shielding would be guiding the magnetic field from north to south pole on its interior. If the material is too thin or has too low of a permeability, the flux will leak out. The best current man made material saturates at about 40 Tesla. Obviously that's less than the 100 trillion that you need. ![enter image description here](https://i.stack.imgur.com/oUmRN.gif) *[Source](http://www.kjmagnetics.com/blog.asp?p=shielding-materials)* [Answer] Sounds like a [railgun](https://en.wikipedia.org/wiki/Railgun). A railgun creates a closed electrical circuit between two rails and the projectile. Current flows up the positive rail, across the projectile, and down the negative rail causing the whole thing to behave like an electromagnet. This creates a circular magnetic field around the rails and the resulting [Lorentz force](https://en.wikipedia.org/wiki/Lorentz_force) propels the projectile. Railguns have many advantages over chemically propelled (ie. gunpowder) weapons. High velocities are achieved by creating extremely high pressures behind the projectile. These high pressures are due to the very rapid expansion of gases from the heat generated by the gunpowder. The velocities are limited to how much pressure the barrel can withstand, how tight the seal is around the projectile to prevent gas leakage, and how fast your gas is expanding; at a certain point, the bullet outruns the explosion. In contrast, a railgun does not use pressure but magnetic force. It is not limited by the speed of the explosive, pressures the barrel can withstand, nor the tolerances of the barrel and projectile. It does introduce [a whole new set of problems](https://en.wikipedia.org/wiki/Railgun#Design_considerations) including power delivery, your rails being bent by the magnetic force (there's as much force trying to shove the rails apart as there is shoving the projectile), and your components melting from all the electricity you're pumping through them and the friction of the projectile running along the rails. High velocity is important in projectiles for three reasons: it increases their range, it makes it easier to aim (less drop to account for), and it makes it pack a bigger wallop. The kinetic energy of a projectile is linear with weight, but exponential with velocity. Making a bullet twice as heavy gives it twice the punch, but fire it at twice the velocity and you deliver *four times* the punch. Modern kinetic penetrater anti-tank rounds are built around this principle: if you fire a high density dart at something fast enough, it will slam into it with so much energy it will melt the armor so fast it will cause an explosion. Several militaries are developing railguns. Right now they're quite large and consume a lot of power which means they're mostly for anti-ship or anti-armor purposes. [The US Navy demonstrations are impressive](https://www.youtube.com/watch?v=h6sAUHwTP4A). Many Navy ships are undergoing big upgrades to their electrical systems for the expected power requirements (also computers). The [US Navy is using a similar idea to railguns to launch aircraft](https://en.wikipedia.org/wiki/Gerald_R._Ford-class_aircraft_carrier#EMALS_launch_system) instead of the traditional steam catapults. Hand held weapons are a way off. The main problem is power density. Until you can make the batteries as light and compact as a clip of ammunition, you won't see railgun battle rifles. What you might see first is a light vehicle mounted railgun-based anti-armor weapon. With the vehicle's power system or an auxiliary generator to call on, you could mount a railgun on a Humvee or Stryker. This would replace the missile systems now in use. A railgun would have a much larger range, more destructive potential, better accuracy, and can carry far more ammunition. This would give mechanized infantry the punch of a tank without the tank. Mostly it would be for bunker-busting, but if an armored vehicle shows up it would be able to destroy it at extreme range. As an aside, what people often think of as a "railgun" is actually a [coilgun](https://en.wikipedia.org/wiki/Coilgun). They also use electromagnetic energy to propel the projectile, but retain the barrel and accelerate the projectile using an external magnetic field. Neither the projectile nor the barrel are part of the circuit. [Answer] Given my understanding of magnetars, which I would put at slightly above average as a space enthusiast myself, I would have to say it depends entirely on how realistic you want to keep things. What immediately comes to mind is a magnetic bomb; you drop something that can generate anything remotely near the level of magnetic power a magnetar can put out, it will likely liquefy anything within miles as the electrons and protons of the atoms that make up everything "nearby" realign themselves in the field. In fact, that would be a horrendous sight if you think about it. Remember the iron filings on a piece of paper with a magnet underneath it, as they align themselves with the magnetic field? That, but stretching up into the sky made up of what was left of buildings, cars, plants, animals, parts of the ground itself, you name it, stretched into suspended filaments of magnetically levitating *stuff*. Absolutely horrifying, and yet almost beautiful in a surreal and dark way. If you wanted to get further away from more "apocalyptic" aspects, and assuming you don't want crazy powerful magnets like ripping holes into other dimensions or something a little more out there (which could be valid, depending on what you wanted and how much sci-fi you wanted), you could maybe look into a sort of "hysteria" weapon. It's well known at this point magnets can affect the neurons in the brain with their ion gradients, making them fire there action potentials when they shouldn't. So, perhaps a weapon using insane magnetic fields isn't powerful enough to tear apart matter, or stick metals to other metals (somehow?) but it could at the least cause hallucinations in targets within the area. The big problem is that the magnetic field moves in all directions, so it's *practically* impossible to direct it in a single direction making it ideal for more of an area of effect type weapon rather than a projectile (since you didn't want railguns). So there's some ideas and suggestions, hopefully it helped any ]
[Question] [ This is a re-phrasing of the question "How Would Metabolism Work For A Zombie?". It's the year 2026 and a new engineered virus turns people into zombies who are very stupid and can only shamble slowly, due to severe brain damage. Also, they get a newfound craving for the flesh of the uninfected. Yay! Most of the zombies' organs are busted and rotting away, yet the zombies' nervous system, skeletal muscles and some sensory organs (namely the eyes and ears) are kept functional by the virus so they could walk around and bite everyone they find... but how? Question: Zombies don't have pumping hearts. If they did they could be killed via staking like vampires, but no. This means the zombies' eyes, ears, nervous system and muscles can't get nutrients and expel waste with blood circulation like they normally do, how would virus help them unlive at all then? (Note: Try to answer with real life science, but if it's not possible please note so in your answer!) [Answer] ## Look no further than the scary Ophiocordyceps Unilateralis fungus. The way the Cordyceps fungus infects ants (and other insects such as moths and beetles) is fascinating, effectively creating a 'secondary metabolism' that replaces standard biological functions. After a spore has entered an insect host, it quickly grows and devours food tissue, draining the host of standard nutrients through which the host relies on for standard biological functioning. The Mycelium (ie. strands) of the fungus branches into various muscle groups and also surrounds the insects brain. By replacing nerve structure in the ant, the fungus is able to physically manipulate muscle fibres directly, bypassing the insects brain completely. From source material: "*the fungus doesn't actually directly attach to an infected ant's brain. Rather, it breaks apart the membrane that covers jaw-muscle fibers, causing contractions strong enough to damage or destroy the muscle filaments that slide past each other when the muscles contract*." [![enter image description here](https://i.stack.imgur.com/rakcV.jpg)](https://i.stack.imgur.com/rakcV.jpg) Image above: Image A uninfected Carpenter Ant muscle fibres - Image B&D: Fungus infected muscle fibres with Vesicles attached. There is evidence the Mycelium attach Vesicles which produce chemicals to coordinate movement and control muscles: "*vesicles come from the fungus, that would suggest whatever is inside plays a role in the muscle contraction—perhaps by secreting some substance that causes spasms in the muscle—or mediates the communication between fungal cells."* In other words, the **fungus can directly manipulate muscle fibres and bypass most biological functions required in normal motor functioning - including circulation, metabolism and nerve communication**. It is doubtful this can occur for a long time, as the nutrient source within the insect is being consumed steadily by the fungus to control the muscles directly, so the host would not be able to move for long - but only needs to move high enough for the fungus to reproduce. It is worth stating the brain of the infected insect is completely isolated - and as far as biologists know is still functioning. Why the fungus leaves the brain unaffected during this controlling phase is a mystery - but as soon as the insect is positioned in an elevated position, the brain is quickly consumed to form an extravagant growth to eject more spores to infect others: [![enter image description here](https://i.stack.imgur.com/qCv3O.jpg)](https://i.stack.imgur.com/qCv3O.jpg) Image Above: Once in an elevated position, a Carpenter Ant's brain (which has been so far been bypassed and is unaffected by the fungus) is quickly consumed to create a spore growth for further transmission of the Cordyceps fungus. Using the above established precedent, by creating a secondary metabolic system **it is indeed possible for a host to have major organ failure, from brain death to heart failure and other major organs and biological systems, and yet still move via direct manipulation of muscle fibres by fungal vesicles, coordinated by Mycelium and fuelled by body nutrient consumption**. Source: <https://arstechnica.com/science/2019/07/study-zombie-ant-death-grip-comes-from-muscle-contractions-not-the-brain/> Source: <https://en.wikipedia.org/wiki/Ophiocordyceps_unilateralis> [Answer] All credit goes to [Thought Potato](https://youtube.com/@ThoughtPotato) on YouTube and his video on [Zombie Biology](https://youtu.be/udlipgfiXlo). TL;DR at the bottom but I would recommend reading the lot. The Zombie virus or as he calls it, the Human Zombic Virus(HZV) is a zoonotic virus. It is from the order Mononegavirales(negative strand RNA viruses) along with Ebola, measles, and rabies. It spread to humans via ticks or tick bitten rats, raccoons, or other animals. Once inside the victim, the virus quickly starts replicating inside the host’s cells. It utilizes a reverse transcriptase enzyme to produce DNA from its own RNA genome and then this DNA is put inside the host’s nucleus. Once inside the nucleus a integrase enzyme incorporates the DNA into the host’s genome; which essentially makes it a pro strand virus. This is very different from other Mononega virus because they do not produce DNA or use the nucleus for replication. Quickly the victim will experience flu-like symptoms. Headaches, fever, and chills, alongside extreme thirst, itching, and increased heart rate and metabolism. There are three stages that Thought Potato describes for HZV. The first stage is the symptoms described above with the victim quickly progressing to stage two. Stage two is a coma that the victim falls into for four to six hours. During this time the fevers reach such a high level that the brain is damaged. Around midway through the coma the victim experiences cardiac arrest and the heart stops indefinitely. The victim’s blood flow, breathing, metabolism, and body temperature plummet, giving bystanders the impression that they have died(reason for why they come from graves and are called the living dead). They then enter stage three. Stage three is when the real zombie appears. The victim, now zombie, rises in a catatonic state. Within an hour they start shambling around looking for flesh. Their heart may be stopped but their brain, though damaged, is still alive. This means that they remember parts of their lives and will try and return home. The brain is still working because of a barely functioning circulatory system. Organ failure and further brain damage remove the victim’s ability to reason, think, drive a car, or use tools. Certain hormones are still produced but serotonin production is almost immediately reduced. The smell of flesh flushes the victim’s brain with adrenaline-like neurotransmitters causing them to go into a frenzy. Now to why they are still able to “live” with no beating heart. Following the cardiac arrest the nervous and circulatory systems are drastically restructured. The nervous system strengthens the pathways and innervating muscles. Skeletal muscles take up the role that the heart once had. They rhythmically contract and relax, pushing blood around. The blood becomes dark and viscous, filled with iron and bile. This increases oxygen levels but causes organs to fail. But because of the strengthened nervous system, the zombie is able to stay mobile much longer. This improved nervous system also allows for much greater regenerative abilities. Thought Potato states that a severed spinal cord is no problem and the zombie is able to walk again only 24 hours later. This is because of increased stem cell production and absence of obstructive glial scarring(scarring in the nervous system). Other things are improved as well, such as smell, strength, and bite force. Sight rapidly decays along with hearing, touch, and the ability to feel pain. Because of organ necrosis and the reduced ability to absorb nutrients from the meat they eat the zombie will die in less than a year. **TL;DR** Zombies can survive the failure of organs because of a strengthened nervous system. This nervous system allows them to stay mobile long after entire limbs have fallen off. The heart is stopped but blood continues flowing because skeletal muscles start rhythmically contracting and relaxing. The blood is dark and viscous because of increased iron and bile but oxygen levels are increased. The slow moving blood causes organs and muscles to experience necrosis and slowly die. Zombies do not last long without a good source and will die from starvation is only a few weeks. A zombie with food can live up to a year before their bodies literally fall apart. [Answer] Being Science Fiction.(Most of whats written its possible, just not with our technology and understanding of the human body, doesn't mean it is impossible) The disease could stop the enzyme release that decomposes the body, it would need to mutate the body quite on a superficial level, eyes would need to suck up moisture from the air around them, as per the waste, lets say the disease maintains itself with the waste produced by cells, but they cant reproduce, only survive this way, making them hunt for food viable. If you go the Fungus route (Although The Last of Us kinda made me not want to go that way) its very easy to explain how, since some mushrooms etc, grow specifically on rotting material. Else you could go for a virus that takes over the brain, while the body is living, the virus sneaks its way to the brain and attaches itself to the part of the brain that controls movement (making them walk janky etc, its a bacteria controlling a body), but that's leaves you with a possible cure that can be manipulated as you wish, either they fuse with the brain completely making it impossible to remove it, or make it removable if it fits the plot, It also has an interesting side to it since it doesn't kill the person, you can choose if zombies are "Trapped" humans or if the parasite has bits of knowledge of the person it infects but cant quite make anything of it, leaving you with confused (and fading) memories as the parasite takes over your mind. Or, hear me out, a soul stealing parasite if your into fantasy [Answer] **St. Vitus Dance** Dancing Mania by Leah Esterianna & Richard the Poor of Ely *Amidst our people here is come The madness of the dance. In every town there now are some Who fall upon a trance. It drives them ever night and day, They scarcely stop for breath, Till some have dropped along the way And some are met by death.* [![enter image description here](https://i.stack.imgur.com/RbTxN.png)](https://i.stack.imgur.com/RbTxN.png) The Cordyceps fungus is probably the best answer if you want the body to move without a beating heart. Even that will require some suspension of biomechanical belief to keep the bipedal zombie on two legs and responding to complex environmental stimulus. If you are willing to leave more organs intact for a period of time, there are also other psychogenic illnesses which may drive manic or psychotic behavior. There were periodic outbreaks of Sydenham's chorea, or St. Vitus' dance, in the middle ages which drove people into manic frenzies, reportedly until they collapsed of exhaustion or died. The rabies virus has significant neurological effect such as hydrophobia, incontrollable movements and, in some animals, increased aggression. Large brain tumors, or extensive brain damage, such as in the case of Phineas Gage, the railroad worker who survived a spike going through his head, are survivable and can cause significant alterations in an individuals personality and motor function. Even the fungus will need to rely on some bodily functions of the host, such as the skeletal structure, some musculature (and maybe inner ear), to keep the body upright, something to metabolize whether that is the hosts tissue directly or feeding from the hosts metabolic system and some sensory organs. <https://en.wikipedia.org/wiki/Dancing_mania> <https://en.wikipedia.org/wiki/Sydenham%27s_chorea> <https://en.wikipedia.org/wiki/Mass_psychogenic_illness> <https://en.wikipedia.org/wiki/Phineas_Gage> [Answer] # It's impossible with modern science Moving, having a nervous system, and biting people is very energy intensive. Without organs like the heart to pump a lot of stuff around the zombie isn't gonna be able to fuel their efforts and would fail. Likewise, without organs to handle toxic byproducts of movement like the liver they'll break down. # It's possible with an alien virus A much more advanced alien race could design a biological organism much more efficiently than we could. They could alter the cells so that they each have complete chemical efficiency and can handle breakdown products. They could alter cells to pump chemicals through them without the need of lungs. None of this is impossible scientifically, just it is centuries or millennia beyond modern science. ]
[Question] [ The zoology of my setting takes place on a mostly dry planet - it's certainly got rainfall, seas, and wetlands in certain ecoregions, and life exists there mostly, but some things still live in more desert-ified territory. After a major extinction event life has gone backwards a few times and ended up evolving very simple bodied megafauna, ones with decentralized nervous systems, no classic vertebrae, and simple organs - most of them are masses of rubbery tissue with "functional cell-regions." Among these simplicities are a lack of internal digestive systems. Most of them have spongy "feeding surfaces" that secrete digestive enzymes, sopping up what's dissolved off the surface. I've built a LOT of evolution around the use of external digestive systems, it's an integral theme to the food chain and I think I've nailed metabolic diversity in the setting, I just need a reason for it to stick around long enough. I am not looking for reasons as to why this *wouldn't* work (honestly, the folks on this site need to be a bit more creative.) **I am asking, what selective pressures would avoid favoring internal digestive systems in arid environments that would otherwise cause the enzymes to dry out?** Of course I want to solve the glaring issue as to **why** this would work and/or how to prevent moisture loss as a result of enzyme secretions. I'm currently working with with ideas around 0% or closer water content in their enzymes, though it might be difficult to make work chemically. [Answer] # Toxic Environment: Your re-evolved world has evolved desperately toxic plants. Perhaps they utilize alternative amino acids, or heavy metals, or horrifyingly destructive neurotoxins (which might explain the decentralized nervous systems). Due to evolutionary bottlenecks, none of the existing species are resistant to the complex mess of toxins. But a solution has been found - digest the toxins before ingesting the plant matter! Amino acids are converted, toxins break down, and heavy metals are slowly chelated out by the digestive goo vomited all over the food. Unfortunately, some parts of the world are too arid and cause the digest to dry out before the food is ready to be eaten. For this, you species evolves an ACTUAL external stomach. The digest forms a hardening, dried coat around the food (a bit like an onion peel) so the moisture is kept in and the enzymes have a chance to work. If you like, the coating can keep out oxygen. Then, the herbivores can have symbiotic anaerobic bacteria that can tolerate the toxins to break down the toxins for them. Then they spread the bacteria from food to food like a sourdough, letting it ferment until ready to be eaten. [Answer] ## Its not always external External stomach only work with extremely small body size, aquatic habitats, or a fibrous body structure. the bigger an animal is the more surface are it needs for digestion, you cant fit enough externally and not loose a lot more than just water. you can't have anything describable as an animals with large size and an external stomach that can sustain it without it making up the vast majority of the organisms surface area which means it will lose water no mater what, a digestive organs surface can't be water tight and work. Sometimes the answer to a biology question is you can't without magic. the only option is to go the starfish route, the stomach is internal most of the time, but the creature inverts it to feed. thus the stomach is only exposed for a very short time. Even then the stomach needs to almost completely surround whatever it is eating. This does mean the creature is immobile when it feeds and it will need to feed for a long time. The stomach needs to completely surround the food source and even then the organism will lose a decent amount of water every time it feeds so it had better be feeding on water rich food sources. [![enter image description here](https://i.stack.imgur.com/uro9N.png)](https://i.stack.imgur.com/uro9N.png) [Answer] I think you are stuck with water vapor being lost if it is exposed to the arid environment. But there can be adaptions to reduce the amount of water being lost such as membranes designed for that purpose. If evaporative cooling is not needed for some type skins or membranes you could envision them as moisture barriers. Also there are people trying to scavenge moisture from the air in desert environments. For inspiration some look to insects and animal as biomimetic examples. So perhaps there are adaptations that your animal has to help collect what little moisture there is in the air. As a route to evolution I mistakenly thought that sea cucumbers had an external stomach, but it seems that they have a single digestive tube that goes through their bodies and sometimes they expel part of their organs to avoid predators, but that got me thinking that for your creature it has an intake and an output and something in the middle as it takes in its nutrients. To drive the evolution perhaps it started out as having a mouth that excreted digestive juices to help pre digest what was going through the rest of the system. Perhaps some type of super saliva. It found that that there were nutritional advantages to wrapping its mouth around stuff and letting the digestive enzymes do their work. As time went on the it expanded the area to extract more nutrients and needed more flexibility to wrap around objects and the distance between what was once its mouth and stomach shortened and the stomach and mouth functions kind of merged, and nearby organs like eyes to remain useful moved further away from the mouth/stomach organ. So eventually you end up with an external stomach to have the flexibility to wrap around, access and stay in contact with the food, but there is still a skin or membrane that keeps the juicy bits out of contact with the air. Or perhaps you could look at amebas or other microorganisms and how/why they surround their food to digest it. [Answer] > > What pressures would force most life to possess external stomachs? > > > **Time Pressure** Internal digestive systems are best to avoid moisture loss. But it takes a long time to develop such specialized tissues that you can hold an airtight container inside yourself. As you say, large complex creatures keep getting wiped out and this leaves large animals that are actually megacolonies of less-specialised cells. Some of the megacolonies are slowly evolving to have more specialised cells, but before they finish they will be wiped out again. As for how they avoid moisture loss, they form an airtight seal around the food. Much like a SCOBY: [![enter image description here](https://i.stack.imgur.com/fozSd.jpg)](https://i.stack.imgur.com/fozSd.jpg) The feeding surfaces only lose moisture when actively feeding. Otherwise they go into sleep mode and dry up. When the colony finds food it sits on top of the food and traps it between the ground and the colony. This stops moisture escaping during the digestive process. There was a similar thing in the Discovers Channel's Alien Planet where the entire ocean had a big SCOBY on it. [Answer] ## Slurploc Bags Thanks to DWKraus for the Toxic Environment answer and to John for his comment on that answer about an single use external container being biologically too expensive. Those got me thinking about how best to externally contain the liquids in a dry environment. Lets take two unpleasant thoughts and combine them. 1. Flies puke up digestive enzymes on their food and slurp/mop up the externally digested goop with their tongues. 2. Some spiders immobilize and cocoon their prey so they can snack on them later. In some cases, this involves digestive enzymes being injected into the prey before the slurping begins. So, icky desert creature gathers plant material or immobilizes prey. Then it spins a watertight cocoon around it, sticks its proboscis in and adds some enzymes to begin the breakdown of the contents into a more nutritious and/or less toxic and/or chocolate flavored and/or less fattening form. This may require several applications of enzymes over time. If necessary, the cocoon can be carried around, hidden, or left in a lair. When the meal is ready, the liquids get slurped out and the solids are discarded. Then a final small application of a different digestive enzyme allows the cocoon to be consumed (waste not, want not). Alternatively, the empty cocoon might even be reused a number of times before being discarded or consumed. Edit: How about leftovers? Size limitations of meal cocoons would primarily be based on how big of a cocoon could be produced (with sufficient strength to contain the contents) and how to carry it. A cooperative group could make a rather large empty cocoon bag. Plants could be carried back without cocooning. If there's an imobilizing venom (a good idea to keep food fresh longer while not letting it try to chew its way out), the prey could also be carried back bagless. Various plants and animals could even be mixed in the same cocoon to make a stew. Preserving food while not drying it would be a huge advantage in a desert environment. Even a comatose animal will run out of oxygen or starve eventually, so our creatues need another solution to further extend the shelf life of their food. If evolution gives the right combination, chemicals that could slow the breakdown of early stage external digestion would be added to the arsenal of venoms and digestive enzymes our creatures already possess. This helps considerably with the problem of keeping food fresh longer. Even better. They've got a preserved stew in the lair and a long day of hunting ahead. Everyone grabs or spins a lunch sized cocoon bag, sucks out enough stew from the big bag, and spits it into their personal bags. Then each one adds the right type and quantity of enzyme to have it be at peak flavor for slurping at lunchtime. Bon appetit! [Answer] How about it's a sort-of colony organism, like a jellyfish? It would produce external "stomachs" that were sort of like it's offspring, or partially so. The creature comes upon some food. It stretches a fleshy bag around the food, and the bag manages to cover the food, then seal shut around it, using musculature. The bag detaches, then the inside of the bag gets to secreting digestive enzymes, and spends however long absorbing the soup. The nutrients are absorbed into it's flesh. Then the host creature comes back and picks up the "stomach", it sticks to it's flesh. Sortof like a placenta to a womb. The host and the stomach grow capillaries into each other, and either pass nutrients through the nutrients soaking through flesh between close capillaries, or else they eventually join blood vessels together and go back to sharing the same blood supply. The host gets a handy source of digestion that it can abandon and come back to, the stomach gets the protection and mobility of the host. Symbiosis. They are genetically the same, but different genes are switched on in the stomach, just as they are in your own organs and limbs. If the host doesn't come back, perhaps it has died, eventually the stomach starts to grow the rest of the parts it needs to become a host / stomach combo itself. So that's also how it reproduces. The nice thing is that this reflects primitive organisms on Earth, it's the sort of thing that might exist in the sea. Of course a host will produce several of these stomachs, and have at least a couple available at any time. Water is preserved by the stomach's tough outer membrane. When the stomach rejoins to the host, perhaps some flap in the membrane opens up to allow them to dock back together, or else the host might dissolve away some of this outer membrane. Perhaps some hormone from the host can cause the membrane to slowly harden and soften as needed. What pressure causes this? I dunno, why are there jellyfish and sea urchins? As long as there's some advantage to it, it can exist, in the web with all the other living things. Long ago everything was weird colony organisms and primitive animals, maybe vertebrates haven't evolved yet. ]
[Question] [ This is a submission for the [Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798). [![Azure Dragon from the Qing Dynasty.](https://i.stack.imgur.com/Ndnc7.png)](https://i.stack.imgur.com/Ndnc7.png) In the culture of China and other East Asian countries, dragons are legendary creatures that resemble snakes with 4 legs. They are big and strong creatures that can somehow influence the weather and cause rainfalls, typhoons, and floods. Unlike European Dragons, Asian Dragons don't always fly or breathe fire. Which real life animal would be closest to a huge lizard that can control the weather? [Answer] # They are related to Komodo Dragons [![enter image description here](https://i.stack.imgur.com/bbT05.png)](https://i.stack.imgur.com/bbT05.png) But for the horns, weather control, and flying, these are very close to being oversized [Komodo Dragons](https://en.wikipedia.org/wiki/Komodo_dragon) (like the one above) with lots of frills added. In fact, our hypothetical Long/Lung will likely be closely related to them, probably their precursor or a side branch. Horns and frills as well as the mane mainly serve mating purposes, the latter being made up very close to how Jurassic Park depicts [Dilophosaurus](https://en.wikipedia.org/wiki/Dilophosaurus) - with neck frills that can be stood up with a few muscles to communicate. # They don't fly, they run like the wind Did you know that Komodo Dragons can run up to 20 miles per hour and are very adept climbers? People might see the dragon on a rock, turn around and next, they see it on a tree, not spotting it making the way there in a spurt. But it ends up there. So it must have flown, yes? Well, actually it ran, but who is to blame the peasant that had better things to do like putting down rice plants? # They are not magical, they can read the weather They don't *influence* the weather, they are highly intelligent and know all about the weather for up to a week - their whole body is pretty much a gigantic weather station. They read the position of the sun with their skin, taste the air currents with their Jacobson’s Organ, hear the air pressure changing with their ears, and listen to the vibrations of the earth for miles with their belly. As a result, they can predict the weather for up to a week in their local area very precisely. If the rain upstream of their dwelling is not coming down, their behavior makes people *think* that they withhold the water from the stream, despite them just adapting to the lower tide and vice versa. As a side effect, a normal Komodo Dragon tastes carrion over up to 6 miles - a Long would be able to taste a battlefield over dozens, if not hundreds of miles and thus appear to be all-knowing. The Battle of Red Cliffs, which reportedly saw between 270 k and 850k participants and several hundredthousand dead (Depending if you believe Zhou Yu or Cao Cao), might even have been tasteable at the Yangtze delta downriver... [Answer] **Olm** [![enter image description here](https://i.stack.imgur.com/52IxH.png)](https://i.stack.imgur.com/52IxH.png) Your dragon bears a resemblence to the Olm. Long snakey body, hairless with itty bitty legs. The olm is a type of blind cave salamander that lives underwater. Master of the Sea and Sky indeed! Another similarity is dragons and Olms are both extraordinarily long lived. An olm might live 100 years. Here they are side-by-side. [![enter image description here](https://i.stack.imgur.com/atoJh.png)](https://i.stack.imgur.com/atoJh.png) The two are almost brothers I reckon. [Answer] ## Axolotl [![enter image description here](https://i.stack.imgur.com/wN7zM.png)](https://i.stack.imgur.com/wN7zM.png) A slightly better fit in the salamander family may be the Axolotl. Unlike other salamanders they have long ornate gills that resemble the frills of an Asian Dragon. They also have certain abilities to get the rumors going about their mystical prowess like their ability to regenerate significant parts of their bodies including arms, legs, eyes, and internal organs. While this is not whether control. Once you attribute one magical characteristic to an elusive and poorly understood animal, it's easy to start seeing other magical properties made up about them. If an offshoot of the axolotl were to evolve to the same size as some of the giant salamanders of southern China, they could reach sizes in excess of 6 ft. very much giving you a strong basis for your Dragon mythos. [Answer] # What are we looking at? These dragons have had a lot of forms throughout the ages, but the current understanding would be something like this: * Mammalian Head * Antlers/Horns * Mane * Barbels * Fish Scales * Serpent Body/Tail * Mammalian Legs * Avian Talons As you can see, this is mostly a mammalian creature. So, let's say it's a mammal, and we'll see where we can get ## Horns Horns are a relatively common feature, both in and out of mammals. They usually evolve to aid in fighting, so a similar origin could occur here. For antlers, a structure like in some extinct giraffids would be quite reasonable ## Barbels/Mane True barbels are not needed in mammals, as they have a tongue instead. But, a barbel-like extension of the nose could be useful in display. This can also extend to the mane, and even to the horns if you'd like ## Scales Mammals usually do not have scales. However, there are a few species with this feature, such as the rat kangaroo and anomalures. Also, the pangolins have scales derived from the fur. Either method could result in a scaly hide ## Serpentine Form The serpentine body seems like more of an issue, but it has a simple answer: Like the weasel, the ancestors of these dragons adapted a narrow form for creeping through tunnels. This anatomy could be retained to the larger form of current dragons The tail is more of an issue, as most mammals have a small, narrow tail. However many species, such as the pangolin, do have a wider tail like a dragon ## Talons Finally, the talons. While these are an obvious adaptation for a grasping animal, there needs to be a reason for it to grasp. One idea could be that this is an arboreal animal. This also somewhat fits with its descriptions of living in the air [Answer] Prehistoric sea reptiles like Nothosaurus reached a length of up to 25 feet and had arms, legs, and a long neck. ]
[Question] [ I'm thinking about the evolution of flight on a tidally locked planet where winds normally are **70 km/h (45 km/h) and can easily reach 120 km/h (75 mph)**. I've recently asked about [clothes humans wear in this environment](https://worldbuilding.stackexchange.com/questions/230121/clothing-against-the-wind), so I asume there must be humans, which implies the existence of other mammals and terrestrial animals. **But what about avian life?** Birds evolved flight to get from tree to tree, but this planet has a tundra-like ecosystem with no big, tall trees or forests of any kind. What's more, the permanent winds on the planet are strong enough to hinder land travel for terrestrial animals. So, with lack of trees and excess of wind, **could flight have developed on this planet?** If so, **what kind of flying/gliding animal could live and thrive on this windy planet?** I'm thinking of possible flying animals. Birds are probably out of the question, but **some gliding animals could do fine in this environment**. Maybe taking advantage of air currents for faster travel or hunting, but without giving up on walking as their principal mean of locomotion. On the other hand, I'm also thinking that in this windy environment, **weighing more could be an evolutionary advantage**. Small and light animals that could have evolved flight would have been wind swept and became extinct much before of having actually been capable of flying. Flight is actually useful, but all the steps in between are not so much. All in all, **animals always make the most of their habitat** and I think for sure they would adapt to these circumstances and even use them in their benefit. So I would like to know what you think about this, and please tell me if something is not clear. Thank you very much! [Answer] In real world, foraging seabirds like red-footed boobies and great frigatebirds can give an idea. These birds are one of the most well-adapted to windy and gusty weather conditions and areas. Frigatebirds can soar for weeks without stopping because they can't land on water and they have the highest ratio of wing surface area compared with body weight (lowest wing loading). These seabirds also have strategies to avoid cyclones/hurricanes by following wind patterns or by climbing to high altitudes to bypass high speeds. [![enter image description here](https://i.stack.imgur.com/ppc76m.jpg)](https://i.stack.imgur.com/ppc76m.jpg) [![enter image description here](https://i.stack.imgur.com/m4gWPm.jpg)](https://i.stack.imgur.com/m4gWPm.jpg) Left: Great Frigatebird - <https://ebird.org/species/grefri> Right: Red-footed Booby (Atlantic) - <https://ebird.org/species/refboo1> For further details, there is a scientific study/publication about their cyclone avoidance behavior and their strategies in windy conditions. Here is some relevant excerpt: > > Boobies generally fly close to the surface, but during the cyclonic event, the three adults escaping the cyclone regularly climbed to high altitudes, reaching 1100 m for one bird, before returning close to the sea surface. This behaviour was not related to gale winds in particular, but there was a tendency for birds to fly at a high altitude with strong winds. > > > When flying under gale conditions, birds of both species use wind differently compared to when they travel with weaker winds. When flying in the presence of weak winds, both species preferentially fly with a tail wind and to a lower extent with a side wind when the wind force increases. Under gale wind conditions, both species use only side winds. Frigatebirds, which are continuously climbing by soaring and descending by gliding at an average altitude of 100–200 m, climb to higher altitudes during gale winds and stay at a high altitude, where they attain very high travel speeds. > > > Weimerskirch, H., Prudor, A. Cyclone avoidance behaviour by foraging seabirds. Sci Rep 9, 5400 (2019). <https://doi.org/10.1038/s41598-019-41481-x> > > > *omitted figure citations* [Answer] Flight evolution on such a planet would be born from a novel (to Earth) approach: the kite. You don't have to climb to the top of a tree and glide down on this world. You just get caught by it and *oof* you're up in the air. Evolution would catch onto this, and start adapting surfaces into little extensible kite limbs so that the creatures could launch. Pretty dramatic way to escape predators (unless they can do the same). From there, they'd adapt different surfaces so that they could steer themselves, and it starts turning into something that resembles proper flight more closely. But they're never going to flap wings like on Earth. What would be the point, when the atmosphere delivers most or all of the power they'd need to stay aloft? Instead, you'll likely see adaptations where the organism can puff itself out like a pufferfish, only to instantly shrink back down when it wants to go into a dive (though, even in that mode they'll have some need to steer themselves). These things will look weird, like something out of a pokemon cartoon or the Kirby video games. [Answer] The flight evolution probably would have come from a carnivorous species that needed to attack by stealth. With those winds, you can probably have a flying squirrel analog that jumps, flaps out and gets pulled up into the air above the wind (assuming the wind is low to surface level wind and not massive gulf streams) and then glide, spot target, dive, grab the prey, and flaps out to soften the landing. Though the winds would pick of an avian creature with hollow bones, your could make your flying squirrel analog have really dense bones and a small surface area (with the flaps tucked). You would also want a 2 stage flap deployment to allow a moderate amount to catch the wind and slow them down (but not achieve lift off), and another deployment that shoots them up with the wind. ]
[Question] [ The werewolves in my setting have a problem. Letting humanity at large know that either they or any other sort of magical creature actually exists is illegal, and so they have to pretend to be human. For the most part, this is pretty easy for them to manage. They can control their transformations basically at will (the only limitations are on when they can use their wolf form, not their human form), and aside from being naturally more fit than the average human, they look identical to one. ...With one exception. A werewolf's androgenic hair (that being beard and body hair) has far more in common with the fur of a wolf than the body hair of a human. It grows in the same places, and at the same speed, as on a human, but it's definitely not human hair. So in order to pass as a human, werewolves can't have beards (or any other body hair a human is likely to see), and need to shave regularly before it gets too long. The question I have is... *how* long? **If someone were trying to conceal the fact that their beard and body hair is actually wolf fur, how long could it get before it became clear, whether by sight or touch, that this stubble isn't natural?** [Answer] To properly answer this question, we must consider the nature of both human sexual hair, i.e. pubic, armpit and beard hair, and canid body hair. Any of us who have a dog - or cat - should be familiar with canid body hair. It is typically around an inch long, give or take, depending on breed, and [75 to 200 microns thick](https://www.whole-dog-journal.com/care/the-importance-of-dog-grooming-and-canine-skin-care/). Canid fur is typically round or nearly round in cross-section. Studies have been made [in great depth](https://www.sciencedirect.com/science/article/pii/S2665910720301195) on the nature of dog hair. Human sexual hair is quite different to both human head hair and canid body hair. Human head hair varies from 17 to 180 microns, averaging about 70 microns. It is typically round or oval in cross-section. [Beard hair](https://beardgrowingpro.com/why-are-beard-hairs-so-thick/) is around twice this thickness, and is highly elliptical or even triangular or trapezoidal in cross-section, around 150 to 200 microns thick. So, beard hair may be around as thick as dog hair, or even thicker, but it also has a significantly different growth pattern. Because of its cross-section, human beard hair is curly, while dog hair lies flat and straight. Beard hair also has irregular reflective properties, while dog hair reflects light more consistently. The question asks how long can a dog hair beard be before another person can tell that it isn't a human beard. Unfortunately, that isn't a simple question despite the obvious differences, depending on the visual acuity of the observer, how closely they observe the subject, and how familiar they are with beards. The latter is more a cultural factor. We can be pretty certain that short (< 1mm) dog hair stubble would be almost indistinguishable from beard hair. The hair could probably get to 2-3mm long before the differences in growth pattern and appearance would begin to become obvious. Observers who don't get too close or who aren't familiar with beards might miss the differences at 5-6mm long. We can be pretty certain that a dog hair 'beard' 10+mm long would be obvious to all but the most unobservant humans with normal vision. However this doesn't account for the feel of a beard vs dog hair. At much over 1-2mm, dog hair would feel much softer than a beard, due to the lower stiffness of dog hair in comparison to beard hair. However, a person with dog hair in place of beard hair would be better able to prevent accidental contact with it than to prevent people from seeing it. [Answer] #### Right Idea Wrong Question? I don't think the length of the hair/fur matters so much as where it grows and how much. [Hair and fur are the same thing](https://www.scientificamerican.com/article/what-is-the-difference-be/). What differentiates people and cats or dogs is roughly how much each grows and how thick it is. Most mammals grow very thick hair: think about a cat or a dog's coat. Generally they uncovered skin you can see are the paw pads, the lips, the tip of the nose and sometimes right at the tip of the tail. There are of course different qualities of hair, some softer and some coarser, and some kinds grow long while others grow short. Think "short haired cat" vs "long haired cat". If your Werewolves have body hair that grows in the same places as humans and in the same way, then they shouldn't have any problem at all. As described, they would be visually indistinguishable from humans. Even if they also grew some softer fur, another person would be unlikely to notice except upon close inspection. Werewolves would only face recognition problems if their hair grew in a lupine pattern --- hair covering the entire body, including the face & extremities. Or, if in a human pattern, then in a lupine colour scheme --- mixtures of various colours of hair rather than the normal human monochromatic pigmentation pattern. [Answer] **Not Very Long** There are breeds of dog with VERY short hair. For example the majestic Wiener dog. [![enter image description here](https://i.stack.imgur.com/rqBv2m.jpg)](https://i.stack.imgur.com/rqBv2m.jpg) These guys feel silky and not stubbly. This is because they have about ten times as many follicles as a person by area. That also means each hair is thinner to compensate. This will give wolf-man a different stubble than human-man. If you don't want discovery by touch, then I suggest the following legend: > > When you shave your beard, it grows back more bristly than before. > > > The interaction of human-type skin and dog-type fur means that wolf-men who shave their beards regularly change the texture so it feels more like a human beard and not like petting the dog. [Answer] Hair and fur are the same thing, but composition is important. Animals have an undercoat, humans do not. If you say that your werewolves do in fact have undercoats, you can safely hand-wave an answer to your own question. Maybe it takes 3 days for a beard to grow in enough before any lupine elements can be distinguished, maybe it takes 5. This would still be difficult (maybe impossible) to determine by sight alone, but a trained examiner could certainly feel the difference. The denizens of your world are aware of werewolves though, so they could have a "hair check" rule where a trained inspector examines any new arrivals in town. During a high-stress period they may even choose to lock individuals up for a few days so that they have no chance to shave. One last note, if it's all androgenic hair, then your werewolves need to shave their entire bodies to avoid inspections. This in and of itself could get suspicious. [Answer] # Beards are all different Many hair on a human body is more complex than the hair on top of the head. The colour for example can differ. My own beard used to be more blond, is now mostly black, with random white and bright orange hairs in there before the grey hairs set in. Yet others have immaculate natural beards of one single colour. The stubbornness of a bread can also differ wildly. Some have easy soft beards, while my own is uncomfortable hard as needle stubble. These large differences can hide a large amount of animal beard hair! Maybe people in the know can tell the difference upon close inspection, but most people will not. As the question says humans do not know about them, they can probably rock beards that are so long they trip over them when playing their electric guitar and chanting in elvish. That does not mean you're out of the woods. Strange wolfish beard patterns can be an indicator. Again, the differences in beards can hide you, depending on the time this plays out and the prevalence. At best people will think it's some funky hair patterns. They'll not cry 'werewolf' at first sign. There's also the coats. The layers could set someone off, but this can again be overlooked at a different style. Regular cutting of the beard and keeping it as short as the most obvious other layer will nip that in the bud. What can set it off is an unusual high amount of hairs growing per square measure of skin, but that would mean you want to grow it to cover up the unusual amount of stubble. A bigger danger is the seasons. Beards do not change much during the seasons, while wolf fur does. If a friend is seasonally rocking much thicker beards, possibly of a different colour even, it'll start to stand out. Then they suddenly start losing their thick beard in spring, making it much thinner. These are really indicators of something *different* instead of just a possible different beard. That means that in climates where the werewolves react to the weather, they need to shave off the beard when it changes. They might be able to get away with shaving it and lettingbit grow out, so it isn't as obvious. It is a risk though. ## Other hair The other hair is under much of the same rules, with the added benefit of people not wanting to talk about it or flaunting it about. "Does the carpet match the drapes" is indicative of the differences of head hair and the rest. Still it is easier to imagine (sadly) that androgenic hair will look too different. You can hope the taboo will prevent talking about it or knowing enough that it is noticeable. Otherwise it is best kept shaven or millimetre short. # Summary The beards can probably flow! The differences in beards can hide a lot of the wolf beards. They might have to shave here and there and possibly colour their beards, but neither is difficult. If there's an unusual amount of hair it is better to let it grow, lest the insane amount of stubble let's people know. Maybe a few exotic wolf beards need to be always shaven short, but it really depends on the breed. Coats and undercoats can be dealt with by shaving one as long as the other, if it is visible/can be felt at all. Seasonal changes can be overcome by shaving all the time when the beard thickensor starts to shag hair everywhere. It might be grown back at some risk or kept no longer than a short humanly full beard. The rest of the hair can possibly hide under the ignorance and taboo of such private parts. Anything that can still be spotted is best shaven clean or kept to millimeters. [Answer] The wolves can make an entire culture to hide. Their beliefs and customs are that they keep on body hair, and this culture would keep people from realizing their werewolves, especially after several years, when new members who are not werewolves join. ]
[Question] [ In a world I'm building, one of the most common creatures is the *Limus* genus. There are two species in this genus, the *Limus silva* and the *Limus informis*. The first is a standard slime that dwells in forests, swamps, and caves. The second is the mimic, a being that can change its color, shape, and texture to lure in prey and avoid predators. The idea I had for them was to be entirely made up of a gelatinous, acidic, cytoplasm-filled, mollusk capable of thought, sensing sound, and creating pseudopods, mimics are capable of changing color, shape, and texture as well. I am wondering if a creature like this could exist in a world similar to our own and what changes I would need to make it more realistic while keeping some core features. ## The non-negotiable features are: * sight * thought * pseudopods * amorphous/gelatinous * texture changing for mimics Other than that any features can be changed [Answer] Based on the characteristics you mentioned, I would say definitely yes, after all, an animal with similar "features" already exists in real life: Octopus. * sight: An octopus has a full range of vision without [the blindspot](https://en.wikipedia.org/wiki/Blind_spot_(vision)) that humans have. * thought: [Octopuses meet every criteria for the definition of intelligence](https://theconversation.com/suckers-for-learning-why-octopuses-are-so-intelligent-162122): they show a great flexibility in obtaining information (using several senses and learning socially), in processing it (through discriminative and conditional learning), in storing it (through long-term memory) and in applying it toward both predators and prey. [Even its tentacles can "think" individually](https://www.sciencedaily.com/releases/2020/11/201102120027.htm). * pseudopods Well, although octopuses have tentacles, I wouldn't say this is a factor that would make the other features implausible. * amorphous/gelatinous You can definitely say that octopuses have a somewhat amorphous body * texture changing for mimics And here's the fun part: [octopuses do have the camouflage feature](https://ocean.si.edu/ocean-life/invertebrates/how-octopuses-and-squids-change-color), they even do it better than other animals that are better known for these characteristics (like chameleons). [Answer] I don't think this kind of being could feasibly exist. First of all, a creature whose base state is gelatinous wouldn't be able to move or do much of anything really because you need some kind of muscle or something similar to move. It might be possible to create a gelatinous compound that could change its color, or possibly even texture without external interference, though I doubt it. A complex brain, or a brain at all is probably impossible. Sensory "organs" might be possible, but they wouldn't be organs, but maybe some kind of bacteria or compound sensitive to light, or temperature (in that case, it wouldn't really see, just know it is there, similar to how scorpions can sense light). However in order to process that information, it would need a brain, and as I mentioned before I doubt it could have one. Its mimic ability would also be impossible. As I said already, it wouldn't be able to move and thus couldn't mimic anything. Even if it could somehow move, its mimic abilities would be limited. I assume you're familiar with shapeshifters from Star Trek: Deep Space Nine. In DS9 you witness changelings mimicking various shapes, from small bird-like creatures to humans, but as we all know matter can't be created or destroyed, and such creature couldn't change its density, and thus couldn't just make itself denser when it doesn't need as much matter, and make itself less dense when it does. But, you're creating a fictional/alternate world, and you don't need to follow our world's laws. You could always make up something in order to justify all its abilities. In this answer, I assumed your creature would be something like a changeling from DS9. [Answer] No not with anything like earth life, every cell can't do everything, the best you could do is making them totipotent that is each cell is capable of changing in to another cell type. slimes are close to possible, look at slime mold slugs, which can do most of what you want except see. the real problem is they all but helpless in a world with fully developed animals. mimics are just impossible, the organisms that use complex changing camouflage are very intelligent, with extremely good eyes, there is no way to just program in that kind of camouflage you need active processing to recognize patterns and shapes and recreate them. ]
[Question] [ After 1000 years of dwelling in apocalyptic shelters, some brave souls have begun exploring the surface. (This is how [Rhydars](https://worldbuilding.stackexchange.com/questions/216870/explaining-an-echolocating-rhino) were discovered and documented, by the way.) Among the first things these 'Vanguard' folk have discovered are Drakit, odd creatures evolved from cats in the harsh surface conditions (between the biological and chemical weaponry, radiation, and magical energy there, mutation is a given). Drakit possess horns (position and design vary between individuals), a spinal ridge (of spines), hairless areas covered in scales (all Drakit have scaled undersides, but individuals may have scaled patches or body parts), and barb-tipped tails with razor-sharp claws and fangs. They are also curious, mischievous, and intelligent enough to understand human body language and obey simple commands, while also being capable of bonding with humans. **In other words, they've been highly domesticated after their discovery and so we thought we knew them. We didn't.** As Vanguard members have ventured further out, shocking reports have come in of larger, stronger Drakit, about the size of a mountain lion, which isn't so surprising. What *is* surprising is their humanoid characteristics. They stand on two legs, make and use tools, and appear about as intelligent as ancient Neanderthals, being self-aware. They also seem to live in male-female pairs, but seem to form groups every so often-they're not exactly social, but they will interact with others of their kind and cooperate to aid each other in hunting or gathering salvage (like their juvenile form, they are drawn to shiny things and hoard metal objects), showing they are capable of altruism and critical thinking patterns. **This begs the question; why the sharp difference? How is it that Drakit get from being felines with intelligence like and equal to a primate's to bipedal, tool-wielding psuedo-hominids? Or in other words, what is behind this odd metamorphosis?** **We've realized:** * **It can't be humans. We've haven't been back long enough to trigger such a change.** * **This is a natural part of the Drakit life cycle; a sort of metamorphosis.** Vanguard members have reported their Drakit becoming more like Drakonomi (that's what we call the adult form) over time, from starting to walk bipedally to suddenly taking, hoarding, and crafting items with resources. These changes occur parallel to an increase in intelligence and a change in the paws, which become more suited for grasping and manipulating objects in older Drakit. * Drakonomi aren't exactly social; they do live in pairs, they do interact if they encounter other Drakonomi, they can and do cooperate to bring down prey or gather resources, but they are aloof, and when they do form groups, they basically just do their own thing. **This strongly suggests that social behavior was and is not the precursor to their higher intelligence.** * Drakit exhibit some small magical abilities, being able to shoot fireballs or streams of obscuring darkness to burn or blind prey or predators. **Drakonomi can do much the same, even better with their high intelligence, and they have good natural weaponry, so they don't seem to need intelligence.** **Any insight on this strange phenomenon would be greatly appreciated, thank you Monster Researchers!** [Answer] ## Chimerism due to magic **I seem to recall that your magic system, mainly chaos energy, served to mutate creatures and occasionally give them traits from other animals. Humans are animals too aren’t they?** So there’s no reason animals and monsters wouldn’t be able to gain human attributes by pure chance. Most likely however, since humans aren’t exactly well equipped to survive, the monsters with human traits won’t flourish. However getting human-like intelligence and opposable thumbs at the same time may be enough to make them ascend to the status of apex predators. Going the convergent evolution route is also an option but as you already mentioned is too slow. For the sake of realism, magic makes the most sense in this scenario (oh, the irony). **Why only late in life?** With magic serving as a mutator only powerful Drakit (dragon kitten?) would only have enough magical power to mutate when fully grown. However, the catch is that not all Drakit would necessarily end up with human traits. An exception would be if adult Drakit transferred their mutated genes to their offspring, in which case we can only wonder why they aren’t born humanoid. **Its most likely because of the brain.** As with most problems in life, the brain is to blame. It is responsible for consuming about 20% of our total energy and growing a large brain is energy intensive. You’ll notice that human babies (I call them human larvae) are completely helpless until they reach a certain age. Meanwhile Cubs don’t take as long to mature, they are ready to hunt much earlier than humans are. In a harsh environment you’d want your offspring to be autonomous as soon as possible. Thus, once a Drakit has reached maturity, it is then good enough at hunting to have the excess resources to grow a big brain. Bipedalism and opposable thumbs would get in the way of running, so that’s probably why they only manifest late in life. There you have it. [Answer] # Evolutionary pressures Primates come in many biological forms with different intelligence. It is theorised that humans gained with their intelligence an abundance of food for a long time, allowing for more frivolous evolutions. Much like a peacock has invested inhuge feathers that are more of a hindrance than a boon, humans could start to invest in intelligence. It is an expensive and difficult part to evolve where the benefits aren't immediate. We can use this as a template. The felines had incredibly little time to evolve, a tiny 1000 years. But we'll accept that due to all the magical and other environments that facilitate rapid evolution for this question. The felines can have wide differences between area's thanks to the specific requirements. One might have plenty of predators, but if you are big with horns you can ward them off while getting plenty of food. The snart felines might have something else. Possibly they grew up in a previous urban area. Their intelligence evolved to make sure they didn't venture into structurally unsafe area's, but also to scavenge for food. Felines who didn't learn to push buttons, use handles or open cans would starve and are unlikely to procreate. The ones that do will have plenty of food. They might invent tools to make it easier. For this a size closer to humans is preferable to have easy access to buttons and handles, making it less energy intensive and leaving them less open to attack while trying to use buttons and such. Though using buttons and such helps them get food, which is best done solo or with a partner so you don't have to share with others, this isn't their only food source. They still hunt and recognise the need for cooperation for higher yields. The buttons etc. could have stopped giving food some time ago, but their intelligence can already support a higher food production. As a leftover they still prefer to be solitary or with a partner, but can still team up easily if the need arises. [Answer] **Humanity left a niche.. and a heritage** An explanation for this very fast development could be *success*: humans disappeared suddenly. Our niche got filled quickly by our pets, accustomed to human artificial environment, that is human's homes and streets. Some went bipedal, to make even better use of that environment. While adjusting their behaviour, many human toys were suddenly in reach: the first thing cats learned when they were not affected by mutations yet, was how to open the fridge, how to open doors, how to crack food stacks. While going bipedal and developing their forelimbs, some cats discovered knives and how to use knives to kill. After some time, when food gets scarce, the animals started predating again. Cats upscaled a bit and look far more dangerous now, as a result of only 60 generations of natural selection and competition ! The reason these physical changes occurred so fast was fast mutations, together with *overpopulation*. There is further development: socially.. human society served as an example, families became pet families became *clans* Even tools production has been observed, but that is a recent development.. it is slow.. predators don't have good forelimbs to be really good at it. Most animals living in the cities reuse human tools, which are abundantly available. They will enjoy the human heritage and make good use of it. But as a result, they look more and more like humans. [Answer] Convergent evolution, the same reason why sharks and dolphins have the same body plan though being separated by several millions of years of evolution. For making and using tools, having a pair of limbs free from the task of supporting the body helps a lot, and this pushes for bipedism. Then, to have a versatile manipulating limb, again the hand with opposable thumb seems to be a good choice, as it is used by humans, raccoons and others. And the tool making will start a positive feedback loop with brain capacity, pushing more toward the anthropomorphism. [Answer] /It can't be humans. We've haven't been back long enough to trigger such a change/ **There are other things that have.** There are other intelligent entities which have been operating on the surface during humankind's long hiatus. These nonhuman intelligences (and there may be more than one group) were heir to considerable human knowledge and have added their own over the centuries. Possibly one group of these intelligent entities are not originally native to the Earth. These entities are not numerous, and they operate in areas far from where the humans are exploring. One group of these intelligent entities were enamored of the Drakonomi and so selectively bred them into companion animals. Some of these went feral and did very well; these are the drakit, which have ranged far over the centuries since they came into being. The intelligent entities are still working on the drakit, and more fanciful and friendly versions (and also some more intelligent versions) now exist though these companions are less fit for life in the wild. The Drakonomi go along pretty much as they have. They might be aware of this group of intelligent entities, if someone can figure out how to talk with them. ]
[Question] [ First, I shall explain the situation. I have a species of humanoids, Astriads, who are already quite stronger on average than humans are. However, this difference isn't great enough to cause problems when it comes to weapon design. Now the problem comes with the **internal magic**. Using the internal magic, they can **greatly empower themselves**. While this isn't that practical for waving heavy weapons around, for archery, this is quite a problem. Where as, say, elite English longbowman would use 140-200 lbs force bow, and according to some stories, 240 lbs bows have been used in some archery competitions worldwide, **elite longbowmen with internal magic** can easily generate pull force far greater, **from 400 pounds up to 800 pounds of pull force**, depending on how good these elites are when it comes to internal magic. My trouble is this: How would they design their bows in order to maximise the impact of increased strength? For example: So far as I understand it(and I might be wrong), if they just went for a thicker longbow, they would not achieve much improvement over 200 lbs bows because of limits of material. So what sort of bow (**without use of modern materials**) do they develop to properly use most of their magically enhanced strength to their benefits? [Answer] **Double bow.** [![double bow](https://i.stack.imgur.com/72Cqs.jpg)](https://i.stack.imgur.com/72Cqs.jpg) <https://www.youtube.com/watch?v=_8ui1irplhM> This dude is an Astriad! You can tell. And besides his might, he is a maker of awesome things and so himself magnitudes more awesome. He has made an awesome double bow with double the pull of a single bow. Thus he can leverage his magestic mightytude without requiring any unobtanium. "But!" you sputter wetly. "But what if my people are even mightier than this bowsmith dude!". Even he would admit it might be possible, because his true might is the making of awesome things. Bowsmith dude would make the mightier dude a 3 bow bow and let mightier dude test it out in a video. "But they are really mighty!" you retort. "Too mighty for a 3 bow bow!". One can add bows in proportion to might until the bow is an adequate match. [Answer] **They wouldn't** Let's set that straight: bows are lousy weapons. Welsh longbows are lousy and encumbering. Throughout the middle ages in Europe there were thousands of battles. Bows were useful in only two of them, both won by the british, and this has made the longbow a sort of mythical status as a medieval uber-weapon in the english-speacken world, just like the absurd glorification of the katana as a superior sword, or the fascination about nazi super-soldiers and super-weapons. Bows are tools for hunting. They are good to hunt small game from short to medium distances. That's what they are good for. In battle they are next to useless, unless a certain combination of tactics and opportunity concurs. There's a tendency in fantasy novels and visual media (movies, videogames) to depict bows as the medieval rifle - or even submachine-gun - which is another misconception. Bows were used in battle, when they were used at all, as a primitive form of field artillery. French knights could drank their wine unconcerned by a heavy rain of arrows, but medieval infantry was nothing but peasants armed with forks. Less than one of every ten of them had a shield, less than one of fifty had a sword and absolutely no-one carried any kind of armor. As a result, when in Agincourt or Crézy the welsh bowmen started shooting arrows, they were aiming to the mass of infantry downhill, not to the knights. Because that's a problem with bows, no matter how powerful or far-reaching: the best bowmen could hit a static human-sized target at a hundred paces 50% of times. What they did was aiming at whole armies, with hundreds at a time. It was carpet-bombing, not sniping. So the french commanders had three options: retreating from the field, allow their infantry to be massacred until they routed or charge to eliminate the bowmen threat. So they decided to charge uphill against a heavily fortified position. It was pikes, tramps and trenches who defeated the french cavalry. Clever use of the bowmen may have decided those battles, but no knight was ever killed by an arrow. Bows can be deadly weapons when used like the tribes of the steppe used them. Their bows were far superior to welsh longbows: they required less force to draw, offered comparable strength and reach, where easier to aim and, specially, *could be used on horse*. By loosing arrows while on the run upon a horse, mongols, huns, scitians and many other peoples of the steppes could run close to their target - otherwise, no matter how powerful the bow, you're gonna miss -, aim carefully avoiding armor and shields, injure the enemy (rarely killing) and run away unscathed. Even then, bows were used in a war of attrition, forcing the enemy to charge and chase the mounted archers to ambush them and finish them with swords. So, you want a superweapon for your insanely strong race of supermen? That's easy: a warhammer. If you want a ranged one, a javelin. Optionally with an atlatl for greater reach. [Answer] ## Ballistas Since your goal is to maximize power, let's think big, increase the weight of the arrows through both size and material so that it could hardly be considered as regular bow ammunitions, and use the power of ballistas to throw them at the enemy. Ballistas are normally siege weapons, rarely used in field battles. This is notably due to the fact that you needed several crew to man it properly along regular maintenance, for a slow rate of fire (comparatively to bows). However, with someone with quadrupled strength, you only need one person to reload and shoot, something which would be done much faster and with much less efforts, leading to really strong shots further away, with very high probably chance of killing anything at the point of impact. Unfortunately, field repairs will be inevitable, but at this level of strength, most kind of mono-string bows1 will need repairs anyway. Indeed, even if they do not break, the components will probably irreversibly bend at the point the draw force is exerted. To counteract this, the ballista could be manned by teams of two mages, alternating between reloading and aiming/repairing as one needs to restore their magic. **Alternatively, miniature-ballistas could be made, something between normal ones and crossbows/bows. They could be set on a foot for the same purpose you lay down heavy-machine-gun, ensuring stability while you manipulate them.** It's making them more of a one fighter weapon, where it reduces the maintenance needed through slightly reduced power output. At the same time, you can aim and reload without moving out of your position and for longer periods of time (it's easier on the muscles). Finally, miniature-ballistas would be much easier to manipulate without springs if you don't wish to reload them in the manner of a crossbow. --- 1 *: Of course, if you favor damage bursts and multitargeting over raw destructive strength, multishot bows should probably be your favorite choice. Just don't forget that these kinds of apparel are not really much faster on the long term, as the reloading is often more complex and mostly improve how many times you have to shoot per ammo, which is not the lengthiest part when shooting quick.* [Answer] Your super archers would use a bow with higher draw weight. What you want is pretty much a bow part of a crossbow, just without frame. Alternatively, you may get crossbows with even higher draw strength. How would you get that draw strength? If those people are taller than human, they may use slightly longer straight bows, as that will give them a bit more force. But a better option would be to make composite bows. A composite bow is a bow made from different materials glued together so it can have as much draw strength as needed, what's more, they can be finely tuned to the user's strength. Composite bow was traditionally made from wood with pieces of sniew and horn. Horn parts were placed where compressive forces affected the bow and sinew allover but mostly in places where stretching forces applied. Composite bows had one massive drawback - glues used were relatively easily dissolved in damp conditions, so they need to be protected from moisture and could even fall apart in very damp areas. Fun fact: good quality welsh longbows were in fact natural composites - they were cut from the area of yew where heartwood and sapwood meet. One of those is resistant to compression and the other to stretch, same principle as in glued composite bows. Composite bows may be straight bow (ancient Egyptians used those), more efficient recurve bow or even reflex bow. The latter types are more efficient because they can store the same amount of energy in a much shorter frame, making it easier to handle and more useful on horseback. Also, skilled bow maker can fine tune the energy store and release curve in those bows. The other alternative would be to use metal bow. It was used already for high draw medieval crossbows and may be useful for the strongest of your people. [Answer] I love magic tags.. **Use magic to create the bow** Suppose you know how much force your super human archer can apply. Then design the appropriate light weight, proper sized material using this, <https://en.wikipedia.org/wiki/Bending_stiffness> after studying this <https://en.wikipedia.org/wiki/Euler%E2%80%93Bernoulli_beam_theory> .. and ask your Magus to create a good stick of that material, and.. a string (chord) of some magic substance that is able to hold the pull and force of the bow.. then, materialize solid steel arrows, and you'll have a nice long range ! A telescope visor would come in handy. ]
[Question] [ Let's say that someone throws an [M67 hand grenade](https://en.wikipedia.org/wiki/M67_grenade) into a completely enclosed room - i.e. the door is the only entrance/exit. How would someone build a suit of armor to functionally negate the following factors? * thermal effects of the grenade blast * the [alveoli](https://en.wikipedia.org/wiki/Pulmonary_alveolus)-[destroying](https://en.wikipedia.org/wiki/Pulmonary_contusion) shockwave caused by 180 grams of [Composition B](https://en.wikipedia.org/wiki/Composition_B) explosive going off * the shrapnel the grenade launches [Answer] Something like an [atmospheric driving suit](https://en.wikipedia.org/wiki/Atmospheric_diving_suit) or ADS, as shown below, might not be perfect but it would certainly be a good place to start. The M67 is actually designed for minimal thermal output so the shock and overpressure are the hardest to mitigate, if a suit of armour can take those then the steel fragments (which are not actually shrapnel apparently) and flame are relatively minor. The fragments may cause minor dents in an ADS but the suit is designed to take 900psi, plus safe margin. Modern suits have 6 hours of sealed operational life support but if working in atmosphere a good engineer should be able to rig an exchange system to use outside air to extend that indefinitely without a direct link that would render the suit sensitive to overpressure. [![enter image description here](https://i.stack.imgur.com/czUUr.jpg)](https://i.stack.imgur.com/czUUr.jpg) [Answer] Just an EOD suit, perhaps with a closed off helmet? ![just an EOD suit](https://i.stack.imgur.com/rKci3.jpg) EOD suits are made of thick material to both absorb a blast and catch shrapnel. They are specifically designed it, I dont see much you can do but add extra layers. ]
[Question] [ I want my continent to be at least 90% desert. It has a square shape with several peninsulas. Kinda like Australia, but more than 3 times bigger and it's not flat(well it does have flat areas, but not to the extent like Australia). It's area is equal to that of North America, or 25,000,000 km2. My continent is located exactly on Earth like planet, in the tropic of Capricorn. [Answer] **Get another continent to the west/northwest so that there will be no monsoons in your main one** Tropical location is already makes the region prone to be desert, because this latitude is affected by the downstream circulation of the [Hadley cells](https://en.wikipedia.org/wiki/Hadley_cell). However, unless something moist air from traveling at low altitudes from the southeast in the North - or northwest in the South, that part of your continent would be subjected to monsoons (so even it's arid, it won't be 90% desert). There may be two solutions to that. One is to have a very massive mountain range blocking air circulation (like @SoronelHaetir had suggested). Another is to place a considerable landmass in the area where your continent would otherwise be getting its water. For example, Arabian peninsula would have been a wet place if not for the Indian subcontinent which absorbs all monsoons. [![Earth deserts](https://i.stack.imgur.com/ZiUbJ.jpg)](https://i.stack.imgur.com/ZiUbJ.jpg) [Answer] Your best bet would be to have an absolutely massive mountain range on the coast wherever the prevailing winds come from to create a rain shadow for the rest of the land. [Answer] **High elevation.** <https://en.wikivoyage.org/wiki/High-elevation_deserts> > > High-elevation deserts are not like the low-lying Sahara, and are > instead inland from oceans. They share some features in common with > continental climates, though these deserts' high elevation reduces > temperature. Since higher latitudes with similar precipitation > patterns typically feature tundra or ice cap climates, high deserts > are typically closer to the equator than the North Pole.. > > > While deserts are sometimes defined by arbitrary precipitation totals, > such as 10 in (250 mm) a year, there are many places around the world > that receive more than this amount but would still be considered "dry" > by temperate-climate standards. Some of the places mentioned in this > article include annual rainfall totals above 10 inches per year, but > still largely or completely share the flora of a desert, and therefore > are designated as "high-elevation deserts" for the sake of this > article's scope. > > > The Tibetan plateau is sizewise the closest thing our world has to what you want. At 25,000,000 square km it is 10% of the size that you ask for. It is still big. <https://en.wikipedia.org/wiki/Tibetan_Plateau> > > The plateau is a high-altitude arid steppe interspersed with mountain > ranges and large brackish lakes. Annual precipitation ranges from 100 > to 300 millimetres (3.9 to 11.8 in) and falls mainly as hail. The > southern and eastern edges of the steppe have grasslands that can > sustainably support populations of nomadic herdsmen, although frost > occurs for six months of the year. Permafrost occurs over extensive > parts of the plateau. Proceeding to the north and northwest, the > plateau becomes progressively higher, colder, and drier, until > reaching the remote Changtang region in the northwestern part of the > plateau. Here the average altitude exceeds 5,000 metres (16,000 ft) > and winter temperatures can drop to −40 °C (−40 °F). > > > The high desert stays dry because air ascending along the slopes at its edges lose moisture as it ascends, cools, and falls in pressure. The edges of this continent where it meets the ocean will be rainy and wet. Up on the plateau the high elevation keeps things drier than they would be lower, because evaporation happens faster at lower air pressure. I think the possibility of steppes is nice because nomads are cool Ferocious hail and endorrheic lakes are another neat aspect of a plateau continent like this. You might see a lake in the distance and arrive to find it is saltier than the ocean. Endorrheic lakes can have some weird stuff going on. [![mono lake tufa towers](https://i.stack.imgur.com/uaDrM.jpg)](https://i.stack.imgur.com/uaDrM.jpg) <https://www.americansouthwest.net/california/mono_lake/index.html> ]
[Question] [ Humans have 2 eyes, under a brow ridge. This ridge seems to have the purpose of protecting the eyes from sunlight. If a human-faced creature had a third eye, where could it be, while being able to link with the other eyes and being protected from sunlight? [Answer] ## It probably wouldn't be linked with the other two eyes. It's not uncommon for creatures to have third eyes. They're called parietal eyes, and grow from the pineal gland. They help with sensing temperature and position. They could take on additional functions in a world of magic. Perhaps the pineal gland helps regulates responses to the supernatural and it could help them have better sensitivity to magic. If you want them protected from sun and water you could have them on the nose, and have an elongated brow, similar to the above, but with a wider brow. [![enter image description here](https://i.stack.imgur.com/VsusX.jpg)](https://i.stack.imgur.com/VsusX.jpg) Or you could have them on the top of the head, to give better awareness upwards. [![enter image description here](https://i.stack.imgur.com/AUQ8O.jpg)](https://i.stack.imgur.com/AUQ8O.jpg) You don't need eyebrows. There are other options, like a skin layer covering the eye, to protect it. [Answer] **The crown of the head.** Let us figure this out starting with real physiology. The pineal gland in humans is a light sensing organs in other vertebrates. Retinoblastoma is a hereditary eye cancer in humans and some babies born with this predisposition develop [trilateral retinoblastoma](https://en.wikipedia.org/wiki/Trilateral_retinoblastoma) with a tumor in each eye and one in the pineal gland. This image shows a tumor on the pineal gland (a different type) but is a good image to see the relationship between the pineal and the rest of the skull. [![pineal tumor](https://i.stack.imgur.com/lBRYA.jpg)](https://i.stack.imgur.com/lBRYA.jpg) <http://www.pedsoncologyeducation.com/pinealtumorsradiology.asp> The pineal is pretty deep but it is right in the midline and there is nothing above it except the falx cerebri dividing the two halves of the cerebrum. The third eye arising from the pineal could be directly under the [fontanelle](https://en.wikipedia.org/wiki/Fontanelle). [![fontanelle](https://i.stack.imgur.com/NxeGO.jpg)](https://i.stack.imgur.com/NxeGO.jpg) This is the spot on the crown of the head where at birth the bones of the skull have not fused - the "soft spot". As a baby grows these bones fuse to produce the dome of bone that is a human skull. In your creatures with three eyes a hole remains in the bone (as it does for some humans!) and the third eye is under this hole in the bone. Just as the orbits provide a ridge of bone to protect our two frontal eyes, the cranial bones will provide bone to protect the third eye on the crown. In infants, there is skin over this hole and tissue as well. This would allow an eye sited here to perceive light and dark. I could imagine a more transparent covering of cartilage could let more light through. As regards coordinating this eye with the others that would be done via the brain as with everything else in the body. The field of view would be different that that of the two frontal eyes. ]
[Question] [ Just a weird question that popped in my head, but since the only real space station in existence always keeps itself squeaky clean, I wonder how one that doesn't have cleanliness as high priority would look? In everyday life, the dirty and gritty look we are used to are influenced, if not created, by gravity. Obviously dusts fall down, but rusts and stains also forms on places that gathers water, which of course is influenced by gravity. In spacecrafts where there is no gravity to pull things, and no system to clean the air, where would the dirty stuff go? Edit: to put in more context, I was thinking about near-future setting without sci-fi artificial gravity, where interplanetary space travel has become common and inevitably someone is going to have lower hygiene standards for their space travels (not necessarily not having air circulation system; some of the comments have pointed out that living in space basically impossible without it). And this question mentions space station, but I suppose spaceships can also be included. So my question really is, if I want to a portray dirty, old, weathered, and badly maintained spacecraft without artificial gravity, how would I do that? Which places would get dirty, by what, and how? And how much can you get away with leaving things dirty until it starts to become serious health hazard? [Answer] Seems likely that under those conditions that electrical attraction and air-flow would dominate. Kind of like how on Earth computers are absolutely great dust collectors. However, indeed, anything that isn't picked up by static-charged surfaces or air-filters is likely to end up in people's lungs. [Answer] It's difficult that you will get rust in a space station, because usually lighter alloys than steel are used for space application, like aluminum, which does not rust. Said that, it has happened in the past that some space missions have become a mess: notoriously, one of the first NASA astronauts to experience space sickness ended up so sick that he had gastrointestinal problems, with the resulting emissions floating around in the space ship. The astronauts did their best to clean the mess up, but they had to deal with organic particles floating around for the whole of their mission. [In another instance](https://www.space.com/39341-john-young-smuggled-corned-beef-space.html), if I remember correctly, an astronaut sneaked a sandwich on board, and after he ate it the crumbles remaining floating around until landing, for which he was reprimanded. (kudos to Charles Staats for the link) This is the kind of situation you have to keep in mind. For the odor, let's hear what [astronauts have to say](https://www.livescience.com/34085-space-smell.html) about their "clean" spaceships > > The interior of the International Space Station smells a little more mundane. Pettit, who recently returned from a second six-month-long mission on the ISS, told SPACE.com, "[The space station] smells like half machine-shop-engine-room-laboratory, and then when you're cooking dinner and you rip open a pouch of stew or something, you can smell a little roast beef." > > > ]
[Question] [ I have always loved the fursuit uniform of the Aztec [Ocelotl warrior](https://en.wikipedia.org/wiki/Jaguar_warrior): [![ocelotl](https://i.stack.imgur.com/wZpM0.jpg)](https://i.stack.imgur.com/wZpM0.jpg) But, to my great disappointment, it turns out that in reality the suit was not made out of an actual jaguar pelt: [the helmets were in fact wooden and the body part painted cotton](https://thelastdiadoch.tumblr.com/post/121200787615/cuauhocelotlcuauhtli-and-ocelotl-eagle-warrior). That's more animal-friendly, but less badass. I want to know if it makes sense for the rich (who can afford it) to wear actual jaguar fur, and taxidermied heads for helmets. **Assuming** that the dimensions work out. My concern is more whether it would make for suitable armour. Note that this theoretical suit would be made with armour as its primary function. The word "taxidermy" may not apply perfectly well. My intent is that you have a jaguar pelt, you treat and reinforce it in some manner (as long as it retains the appearance of the animal) and you put it on to go to war. Specific concerns that determine armour suitability for this thing: * The suit should hold up against the weapons of the time - those being sharp slicing weapons as well as arrows and spears - to a comparable extent as the cotton armours they really used. Fur armour is a common fantasy trope - even if its historicity is [questionable](https://www.reddit.com/r/Norse/comments/l4o1lb/was_the_fur_armor_historical/) - so I expect that it should have some resistance. Cotton with fur on top is also an option. * The suit should last, it should not rot like a carcass. [Regular taxidermies](https://www.taxidermy.net/threads/51774/) and [fur coats](https://www.truthaboutfur.com/en/how-long-can-i-expect-my-fur-coat-to-last) can both last for decades, so this should not be a problem. * The suit should be usable in the tropical climate. It did suit the jaguar without trapping too much heat, so I have faith it should do the same for a person. I also wish to keep using the jaguar's skull; both to shape the jaguar's head and to help protect the wearer's head. There can be padding inside to make it fit, perhaps even wooden reinforcement if necessary, should the bone become brittle as it dries out. What do you think, could this work as armour? Do I have any of the above plainly wrong, and/or are there any other weaknesses that would make this suit a poor fit for the battlefield? [Answer] **<1 out of 3 feasible** Looking at the three concerns specifically mentioned in reverse order: * Usable in a tropical climate - simply no. It suits a [jaguar](https://en.wikipedia.org/wiki/Jaguar) because, as per the link: > > The jaguar uses a stalk-and-ambush strategy when hunting, rather than > chasing prey. The cat will walk slowly down forest paths, listening > for and stalking prey before rushing or ambushing. The jaguar attacks > from cover and usually from a target's blind spot with a quick pounce > > > The jaguar is also primarily "active" during the night (or daytime in heavily shaded forests) and, like most big cats, pants or goes swimming to cool off. None of this applies to humans. Humans warriors in primitive societies are primarily active during the day, tend to engage in prolonged medium-to-high intensity activity during hottest periods (rather than a slow wander followed by a brief pounce) and rely on perspiration for cooling rather than panting. Thin cotton leg and arm coverings are porous enough to allow effective cooling and even quilted cotton torso protection can be made breathable, but tight fur is not an option. Speaking from experience - in a tropical environment wearing a helmet, body armour, loose-fitting long-sleeve cotton shirt and cotton trousers is bearable but unpleasant. Heat exhaustion will nail you if wearing anything less breathable while exercising for any extended period. * The suit should last - no, not while being worn regularly in a tropical climate. The link you provided on fur coats has another Q&A a little further down asking "[how do I protect my furs in the off season](https://www.truthaboutfur.com/en/how-do-i-protect-my-furs-in-the-off-season)", to which the answer is: > > The best way to ensure that your fur will last for many years is to > have it professionally cleaned and stored through the off-season by > your local retail furrier in a temperature- and humidity-controlled > storage vault. > > > [Another site](https://modeandaffaire.com/pages/caring-for-your-fur) provides this advice: > > FUR HATES THE HEAT BUT LOVES THE COLD > > > Nothing shortens the life of your fur like keeping it in your closet > during a long, hot summer. If at all possible, we suggest you store > your fur garments in cold storage when you have finished wearing it > for the season, this is one of the most important steps you can take > in preserving your furs. > > > In short, fur garments can last a long time if kept carefully in the right environment. The Aztecs are not in the right environment. * The suit should hold up against the weapons of the time. For reasons discussed in other answers, unreinforced fur isn't up to the task - jaguars aren't especially proof against arrows or spears and their resistance to blunt force trauma is more due to their musculature than their skin. However, putting the same quilted cotton armour "1 1/2 to 2 fingers thick" under the fur should give it the same or possibly slightly superior protective qualities compared to the same quilted cotton armour alone. This one is hard to be certain on - layering materials on top of armour sometimes has unexpected or counterintuitive consequences, where an additional layer can actually make things worse by making certain weapons more likely to "dig in" and do damage rather than ricochet off. I cannot see any way to test this particular scenario without extensive testing using reconstructed armour and weapons - this would be really fun to do, but I lack the time and budget. As for using the skull of a jaguar as a helmet - the skull really isn't the right shape and even the skull of the largest jaguar known would be too small to fit a midget's head. In order to use a jaguar skull as a helmet it would require a skull about twice as wide as that of the widest known specimen and then would still need extensive carving to take out the internal structure. The eye sockets of the skull would be a massive weakness if the wearer was attacked from the side. So even disregarding the size issue (which also applies to the legs and arms of the suit) a jaguar skull would be a poor helmet for a human warrior. My advice at the end of this for the well-off Ocelotl warrior with an excess of money and willingness to be uncomfortable is: * Embed part of the skull of a jaguar into the top of your helmet if you need the authenticity, but keep the wooden structure for protection. * Put jaguar hide over your torso armour but be careful of overheating and be prepared to replace it every year or so, as fur does not like the heat, crushing or most cleaning methods. * Retain single-layer cotton garments on the arms and legs. [Answer] # Mostly, no. The processing of the skin in Taxidermy is focused on retaining the natural appearance as closely as possible. Flexibility and durability are *distant* secondary goals. Wearbility is not even considered. Very often, the chemicals used in taxidermy to process a natural pelt are quite toxic. For leathermaking, the opposite is true. Durability is paramount, with strong attention to wearability, safety (no toxins, no allergens, no dye transfer), and some attention to appearance and texture. For **armor** the same is true with an even more different balance. Strength and durability are paramount, while comfort and appearance are of secondary concern. Simply put, taxidermied Jaguar will look very impressive, but will not be waterproof, safe or easy to wear, and will have the damage resistance of wet paper towels. Great for ceremonies, suicidal to wear into battle. [Answer] The reason why the jaguar pelt is not a good armor is that is does not offer good defense against common Aztec weapons. One real common weapon was simply a handle with a good sized rock embedded in the end. A wooden helmet offers much better protection against that. You state that the jaguar fur protected the jaguar, but that was also in context of an animal that could move much faster in tight places than humans can. The jaguar does not depend on its pelt for defense, but relies on its claws and teeth. The cotton armor is not simply something like jeans material. It is possible to process cotton so that it is much thicker with interlocking fibers that resist stabbing or cutting where the pelt would not. [Answer] Yes. The trick is to put a taxedermied jaguar pelt on top of normal armor. **Would it protect as well as competing armors?** It took me almost 30 minutes to find a reliable source, but Aztec armor includes the [ichcahuipilli](https://nahuatl.uoregon.edu/content/ichcahuipilli) and the [amatzoncalli](https://nahuatl.uoregon.edu/content/amatzoncalli). The former is made of cotton or wool, and the latter is made of paper. It should be easy to sow or glue a pelt on top of these materials. The helmet would not be made from a jaguar skull, but it would look like one. **Would it last as long as competing armors?** The armor could to stored in a cool place to preserve the pelt's quality. Assuming the competing armors were not designed to last through many battles, by the time the heat damaged the pelt the armor would have to be replaced anyway. **Is it suitable for a tropical climate?** From a physics point of view, layering anything on top of anything increases insulation. The greater this effect is regarding jaguar fur, the more energy the jaguar needs to spend on thermoregulation. This heavily implies that the armor's additional layer would not significantly increase the insulation of the armor, assuming the taxidermy process does not cause anything weird to happen. **Would warriors desire cosmetic changes such as this?** You did not ask this question, but since the pelt is purely cosmetic this is a reasonable question to ask considering how much effort is needed to kill a jaguar. Some medieval armor included a metal [codpiece](https://www.huffpost.com/entry/crack-attack_b_543872) (SFW, but you may get some weird looks). I think the effort of mining, smelting, and forging metal is comparable to that of killing a jaguar, but I do not have a citation for this. ]
[Question] [ Recently I've been picking back up my worldbuilding for a DND campaign I've been lightly working on for a few years. One of the ideas I have are bovine dwarves, mostly based off of yaks or muskoxen. Mostly because... Y'know, long hair, lives in mountainous climates, and because I have a trend in basing my dnd races off of animals (feline elves, marsupial goblins, porcine orcs, you can smell what I'm stepping in). Would it be possible for a bovine that lives in an alpine forest environment (that later moves to the mountains) to undergo similar evolution that humans went through? Becoming bipedal, tool usage, speech, etc. [Answer] The very first mammals are believed to have been less than a handful of rodent species. Those proto-rats eventually evolved into platypuses, monkeys and even whales. Given enough time and pressure a species can evolve in any direction. For bipedalism, a hooved creature could first evolve to be leaner because it needs agility rather than bulk, and then it could evolve into bipedalism because it allows it to reach higher leaves. A longer neck like that of giraffes would also do, but mutations are random and you go with whatever you get. By the way, hooved creatures standing on two legs already happens nowadays. Some species of deer in Africa do that: [![A deer standing on two legs](https://i.stack.imgur.com/Vh91j.png)](https://i.stack.imgur.com/Vh91j.png) They don't walk like that, they just stand like that while grabbing leaves. But it's a step towards bipedalism. As for intelligence and tool usage, they will evolve if they help the creature survive. Could take millions of years though. We humans had an advantage when it comes to tool usage because of opposable thumbs, which our ancestors had due to living on trees. Your herbivores could develop opposable hooves/digits in order to grab leaves, [like some herbivore, non-climbing dinosaurs once did](https://worldbuilding.stackexchange.com/a/100825/21222). Intelligence is the trickiest part. Even we humans are still figuring that part out. But again, it's a matter of survival. If the creatures learn how to make spears and it leads them into surviving better, then bigger brains will stay. [Going bipedal makes it harder to be smart though](https://www.smbc-comics.com/comic/evolution-3). [Answer] Opposable hands designs have evolved separately in rodents, primates, dinosaurs, and reptiles and in all cases, they seem to have evolved out of a need to climb. While hooves seem like a bad starting place for designing nimble grasping appendages, the mountain goats of today could easily be a transitional species moving in that direction. Mountain goats are members of the bovidae family making them very closely related to bovines. One of their adaptations that help them climb so well is that their hooves have pliable, rubbery pads and their toes can spread to improve balance and grip. If Mountain Goats could evolve these features; so, could a true bovine living in the same niche like a Mountain Anoa. In a few thousand more generations mountain goat hooves will likely evolve to be better and better at grasping things, since those who do not grasp so well are more prone to be selected against. In this respect it is very much possible for them to evolve their own version of hands, and appendages that can rotate out more for better hugging trees and cliff faces. When you consider that the average bovine brain is about the same size or bigger than that of a chimpanzee, then it also seem reasonable that once you give them hands, intelligence and tool usage would be a relatively easy next step. As forelimbs become more and more important for things other than walking, bipedalism will become evolutionarily favored. [![enter image description here](https://i.stack.imgur.com/Q92AY.png)](https://i.stack.imgur.com/Q92AY.png) ]
[Question] [ OK, faster than light isn't possible & a merely significant fraction of it can begin to stretch the bounds of reasonable reality as that fraction increases // so a less unreal way to allow us our interstellar travel is needed. I'm opting for Cryo-Sleep. So that's pods that lower body temperature until you reach a point below freezing where all biological activity is suspended. As well as the obvious cooling equipment these will include a haemodialysis machine, urinary catheter & intravenous drip. The subject is initially sedated & then over a period of time their blood is saturated with antifreeze proteins, urea, glucose and glycogen as they're dehydrated as far as the human body can tolerate while the temperature is slowly dropped. By the end of three days the temperature is below freezing & they're a human popsicle. When they arrive the process is reversed as they're slowly thawed out. **Is this plausible for unmodified humans?** [Note: by unaltered / unmodified I mean only that they've not been genetically modified] [![enter image description here](https://i.stack.imgur.com/HRj7X.jpg)](https://i.stack.imgur.com/HRj7X.jpg) A few of the links & resources I've been using. > > [BBC - Earth, When your veins fill with ice:](http://www.bbc.co.uk/earth/story/20160308-how-one-squirrel-manages-to-survive-being-frozen) > *"University of California, Berkeley and Sheba > Medical Center in Israel, successfully used antifreeze proteins > isolated from Antarctic fish to freeze and preserve rat hearts for 21 > hours // transplanted into recipient > rats, where they continued to beat for at least 24 hours"* > > > For at least 24 hours presumably means the subjects were destroyed after 24 hours so the long term success (or not-success) of the technique for longer periods isn't clear either way from that. * [BBC - Earth, When your veins fill with ice](http://www.bbc.co.uk/earth/story/20160308-how-one-squirrel-manages-to-survive-being-frozen) * [ScienceDirect, Cloning, characterization, and expression of glucose transporter 2 in the freeze-tolerant wood frog](https://www.sciencedirect.com/science/article/abs/pii/S0304416513005382?via%3Dihub) * [EarthTouch, 5 animals & 1 superbug that can freeze, thaw & live](https://www.earthtouchnews.com/wtf/wtf/5-animals-1-superbug-that-can-freeze-thaw-live/) [Answer] You’ve done some great research and have outlined an effective theoretical approach to putting people on ice. However, ultimately the success of a cryonic procedure comes down to how good we are at repairing tissue. To thaw out a colonist and have more than meat, you need some sort of nanobot or other cellular repair technology that you can use on your patients as they thaw out. Here are the main examples of damage you would need to treat. ## Cold Damage When you freeze your patient, the most obvious (and acute) source of damage to the body is the formation of ice crystals. Large-scale tissue structures are mulched, cell membranes are blown apart, and even delicate internal structures and proteins are disrupted. As anyone who has thawed and cooked a frozen onion or hamburger can attest, the act of freezing and then thawing results in a noticeable change in texture and flavour (and a significant loss of fluids as everything drains out of the now perforated internal structures). I'm listing this one for completeness' sake, but you have a solid theoretical way of avoiding this issue. So with direct mechanical trauma solved, what else is there? ## Chemical Activity There are a great many molecular structures in a given cell that are delicate and energetically intensive to maintain. While reducing temperature reduces chemical activity, there is some debate as to how cold you need to get before the more short-lived molecular structures in the body begin to degrade. When your cells are warm enough to engage in homeostasis, this short lifespan is an asset. If it is cold enough to stop biological activity and inhibit chemical activity however, it becomes a liability. These chemical springs will certainly uncoil less quickly, but they will still uncoil. ATP will dephosphorylate, RNA will slowly fall apart, etc. Theoretically, you could get around this by freezing people down close to absolute zero, but that’s a challenge even on Earth where heat is a lot easier to get rid of than it is in space. I would imagine a compromise is made here, finding a minimum feasible temperature that balances reduced the decay damage (and repair/thaw time) with the machinery needed to keep everyone frozen. ## Radioactive Decay We contain quantities of radioisotopes of carbon, phosphorus, and other elements. These are constantly decaying, and your body is continually repairing this damage. However, if you are on ice, radioactive decay will continue (it doesn’t particularly care about temperature) but the repair systems are now on hold. Damage from radioisotopes such as C-14 and P-40 undergoing their usual decay will accrue throughout the body, both in the form of the beta particles released and in the form of a generally rather important phosphorus suddenly being calcium and carbon being nitrogen, with knock-on effects for the molecule or protein it is a part of. It’s worth noting that these are both quite stable radioisotopes with long half-lives (10^3 years for C-14, 10^9 for P-40), but we contain a *lot* of both, and both are incredibly important wherever they are. Carbon is the backbone of essentially every organic molecule, and the change in electronics and available covalent bonds from C to N presents pressing structural issues. And with phosphorus, it's almost worse: each nucleotide in your DNA has two of these, one joining it to each of the nucleotides on either side. Neither are great atoms to suddenly not have, and then there's that beta particle I mentioned - it's also highly likely to find a new friend in the area. ## Conclusion So, damage will accrue beyond the initial freezing. Ultimately, what your society will need to make this viable is a solid foundation of cellular repair technology, in whatever form that takes. Nanomachines are generally the most popular take here, and if you are spending three days to freeze someone, spending another three to infuse them with repair bots as they thaw out seems pretty reasonable. This does mean your setting has access to healing nanobots, which will have knock-on effects on human lifespan, disease, and what exactly constitutes ‘serious injury’ and ‘long-term treatment’ if most injuries are curable by a day or so on the slab while the nanites work. ## Additional Information I’ve done a surface level discussion of these topics, but if you want more depth I would recommend a couple YouTube videos by Isaac Arthur, a physicist and futurist, that discuss this topic. One is more general information on Cryonics (he focuses on the societal aspects of the technology and its uses but also gives more details on limitations), while the other is more focused on sleeper ships like your use case. [Cryonics: Frozen Civilizations](https://www.youtube.com/watch?v=V_u9Za00uBY) [Sleeper Ships](https://www.youtube.com/watch?v=fM-JHvg-ZCM) [Answer] > > The subject is initially sedated & then over a period of time their blood is saturated with antifreeze proteins, urea, **glucose and glycogen** as they're dehydrated as far as the human body can tolerate while the temperature is slowly dropped. > > > By the end of three days the temperature is below freezing & they're a human popsicle. > > > You want your description of the process to sound plausible, not to be reproducible. Don't go with too many details on what is used and why; reading your description the first thing I thought was "why are they giving glycogen and glucose if the subject is going to be hibernated? The metabolic need will be 0 and all that chemical energy lying around is just an invitation for decomposers". Stay vague: the fewer details you give, the fewer hooking points there are for anybody to question your description. Again, your goal is apparent plausibility, not reproducibility. Mentioning antifreeze proteins is vague enough, do the same with other substances. [Answer] **Consider medically induced torpor states instead of cryogenics** [Torpor - wikipedia](https://en.wikipedia.org/wiki/Torpor) I haven't linked them here but there are several articles published recently on research into inducing 'hybernation' like states in mammals that don't naturally enter such states e.g rabbits. For extended periods of torpor you could 'realistically' adapt research from some parts of cryogenics research E.G. anti-freeze compounds and computer controlled intravenous oxygenation/nourishment/muscle stimulation etc to greatly extend the period of torpor sleep out to several months/years and/or lower the body's core temperature slightly more to induce an even more effective torpor state. I would suggest however that crew/passengers would have to cycle through periods of raised body temperature/dream states to maintain their mental faculties. Also after reaching the maximum 'safe' limit for induced hibernation people would have to be woken and allowed access to normal movement, exercise and food for an extended period. So if as per you example the trip takes 100 years crew would have shifts in pods, followed by rest period during which they recover and then an active duty shift. So from the crews perspective the trip might have 3 years of torpor followed by 1-3 month recovery period and 3-6 months of normal work before they go back to sleep for another 3 years. You could go with say an 80/20 sleep awake cycle for the trip. The downside is that you still have the problem of part of the crew being active for a one tenth to one third third of the trip (choose the stats you want) which increases the use of consumables. The upsides however are that; **A) Induced Hybernation is actively being explored for space travel**, cryogenics is not. Fact is we're not even close to solving the complexities involved in reviving advanced living organisms/tissue from deep frozen states after extended periods of cryo. **B)** there has recently been some evidence come to light from experiments with animals that spending a period of time in an induced torpor may well extend an animals natural lifespan. So your crew might find their 'normal' life spans being greatly extended simply because their bodies have been in 'resting state's for such long periods that they haven't accumulated the normal amounts of damage associated with aging. So, if for example the average lifespan in your word is 120 years and the average age of the crew is 30(ish) when they start the tip and you go with the 80/20 sleep/wake cycle then assuming drugs & cold etc do help slow down the aging process by just half they'll all be about 90 when they arrive. The equivalent of say a healthy 60 today. Not good but not bad either. And you of course you can play with the figures. **And note you *can* cryofreeze eggs sperm or ova.** So expanding the population is readily doable. Sorry if this is not the answer you wanted but for world building purposes with slow travel times it is 'doable'. Good research BTW [Answer] **Microwaves could** I'm not kidding. Just Microwave the almost corpses perpetually, at the direct amplitude/frequency to prevent them from freezing. You might cause other types of damage but you would successfully stop damage due to ice crystals forming from occurring. You would need to perpetually pump heat out, and due to how long the journey is, any sort of active radiator where you spray out materials to take away waste heat like is inferred but never actually directly stated in the expanse because the idea is mildly stupid is an option. It's going to need some large radiators. As for the microwave solution, the idea is inspired by some research on cooler technology to keep meat fresh to prevent ice crystal formation.After all, what are humans made of, but meat? The idea's that you use microwaves to perpetually keep JUST the ice crystals from freezing and at the same time cool them down to keep them at cryogenic temperatures, which produces a tremendous amount of waste heat, since they are at freezing temperature but you're cooling them down and heating them up at the same time to prevent ice crystal formation.This is something being contemplated to keep meat fresher in coolers, by preventing ice crystal formation. That's the exact same problem with cryogenic preservation, ice crystal formation which are both problems for the same reason, that being ice disrupting cell membranes and others. ]
[Question] [ [![enter image description here](https://i.stack.imgur.com/k0FNj.jpg)](https://i.stack.imgur.com/k0FNj.jpg) In my world there exists a sort of "chameleon" like cloak that has the ability to change its color to blend in with its surroundings, the fabric is thus highly sought after for its camouflage capabilities. So I am looking for a way to justify/explain this cloak's "camouflage/chameleon" capabilities. Ideally a semi-plausible science-based explanation should do, if completely impossible then it's no big deal I'm just going to chalk it all up to "magic". [Answer] Fun fact: octopuses not only mimic the color of their surroundings perfectly, they can also mimic texture. [Science knows how octopus skin works](https://www.youtube.com/watch?v=mFP_AjJeP-M). It would be possible to create cloth with elements similar to the chromatophores, iridophores, leucophores and papillae of octopus skin so as to have perfect camouflage. With a signal network similar to that behind an e-ink screen (which is widespread technology today) it would be possible to control each color and texture element individually. We could even outdo octopuses at it. We can miniaturize electronic components so that an artificial neural network could have more neurons than an actual octopus but in a much smaller space. We can also cut the camouflage in different shapes, and we can make components with blue pigments which most octopus species lack. Or you can just go through it like a necromancer would and wear actual octopus skin. You need to find a way to keep it alive artificially and to control its neural network. We can control the neural network of insects with current technology - maybe we could wire up some mollusks in the next decade or two. [Answer] Fiber optics are thin clear fibers that take light in one end, contain and warp the light along its length, then project that light out of the opposite end. If you were to weave fiber optics through a sort of suit such that you always have ends of the fiber sticking out on opposite sides of you, the you could organize the fibers in such a way that the light hitting your backside would be projected in front of you in roughly the same colors and patterns. That said, I would recommend a skin-tight suit rather than a flowy cloak. This is because a cloak will fold in shift causing any patterns behind you to be distorted based on how the fabric drapes on you at any given time. If you want a true "cloak" that does this, then your cloak will need some manner of proprioception to be able to adjust how it projects light based on its current shape. The best way to do that is for your cloak to actually be alive. An octopus can do this quite well; so, your cloak may actually be some made up distant relative to the octopus that has some manner of symbiotic relationship with its wairer. [Answer] You know how some smartphone apps can detect rotation? Image millions of tiny smartphone screens making up the surface of the cloak, sort of like how millions of pixels make up the surface of a TV screen. They each constantly capture the background at different angle, depending on which direction each screen is facing. Now, immediately displaying what the screens sees will turn the cloak into somewhat of a mirror, and we don't want that. That's why each tiny screen detects any rotations precisely, and only displays the captured colors when facing the right direction. ]
[Question] [ In my worldbuilding project, I'm currently thinking about the society of my bird people. I like to put actual science (or "science") into my worldbuilding, and I'm trying to include as much real-life bird biology and sociology as it makes sense to do in an advanced society, but I can't find any good information about gender roles within real-life birds if there are any at all. The race itself is primarily based upon Toucans, but again, I have yet to find any good information about any gender roles birds may or may not have, Toucans included. Any help is much appreciated! [Answer] **Bury your Wife.** [  ![enter image description here](https://i.stack.imgur.com/88Qs2l.jpg)](https://i.stack.imgur.com/88Qs2l.jpg) You asked about Toucans not Hornbills. But the birds are similar in habitat and appearance. The Hornbill is the African version of the South/Central American Toucan. Here is an interesting fact about Hornbill gender roles. They nest and lay their eggs in tree hollows. To prevent predators, some species enclose the female inside with her eggs. They leave only an opening large enough to pass several hundred figs per day, and the male gathers food for his wife and children until they are large enough to fend for themselves. For Hornbill people this suggests a society where children and mothers are never to be seen in public. Once you have children you are not allowed to leave the house. All contact with the outside world must be done through your husband. During the last century however the younger generation decided this practice is a massive Hornbillperson-rights violation. It was made illegal and is quickly passing out of fashion. Mostly in rural parts of the world, some mothers still enclose themselves voluntarily. It is prickly issue whether these women are doing enclosure voluntarily, or whether they are being coerced. For the most part mothers are allowed to leave the house, provided they do not take their children with them, or act in any way that reveals them self as a mother. **Sugar Mommy.** [![enter image description here](https://scx2.b-cdn.net/gfx/news/2018/indianpeafow.jpg)](https://scx2.b-cdn.net/gfx/news/2018/indianpeafow.jpg) Another type of birds where the males and females are hugely different is peafowl. The males have huge ridiculous tails and the females are much more sensible. The females find these huge tails hot as hell [[citation needed]](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed) but they make flying difficult and cost a lot of energy to maintain. For Peafowl people this might leads to a situation where males are seen primarily as sex objects and the women are the breadwinners. Most buildings are only accessible to women and the men cannot even fit inside without damaging their magnificent tails! Can you imagine the shame of it! The dream of every peafowl CEO is to build a marvelous golden atrium onto the side of her house where she provides for the every need of her harem of magnificent-tailed husbands, who swagger and shake back and forth all day long and wait for the mistress to come home. [Answer] # Fairly egalitarian, male gift-giving Toucans don't show much sexual dimorphism, that's usually a sign that their behavior doesn't differ much by sex, either. Apparently males have longer, thinner beaks on average, that's about the only difference, and owners of pet toucans find it unreliable enough that they usually sex them with blood tests. From what I could find, courtship involves the male bringing a female a morsel of food, and while courting the two often pass this food back and forth between their beaks, and when the female is convinced, she eats the treat. They nest in trees, and both parents bring food to chicks. They are monogamous during the mating season, though they may choose different partners next year. Of course, other species of birds will differ. For example, if you based them off of bower birds, males would all be artists with no involvement in raising their young. [Answer] The potential answers vary massively. Bird sexual dimorphism and gender roles are not consistent across the 10,000 extant species, ranging from species where males are more dominant and aggressive than females (e.g., ostriches, ducks) to species that have almost no dimorphism, to species where the females are larger and more muscular than males (most birds of prey) and some where the females keep a harem of males around to look after her offspring (most jacanas). And then you have the acorn woodpecker (*Melanerpes formicivorus*) that can't make up its dang mind and exhibits monogamy, polyandry, and polygyny all within the same population. One thing that is relatively wide-spread among birds is that more often than not it is the *male* who looks after raising the offspring after the female lays the eggs, rather than the female (as we mammals would expect). This is in part because it balances out parental contributions to reproduction, the female wastes resources in creating and gestating the egg, whereas the male spends his resources in caring for the babies after they are laid or hatched (and may be better than the female at protecting the young if he is larger and has larger weapons, e.g. cassowaries). This isn't universal, in some birds both parents care for the young and in one family (Megapodidae) there is *no* parental care at all, [but the majority of birds either have no defined gender roles or the male performs the majority of the care](http://people.eku.edu/ritchisong/parentalcare.html). Funnily enough, it is thought that some dinosaurs may have been the same way, troodontids and dromaeosaurs are thought to have had male-biased or biparental parental care, though oviraptorosaurs seem to have been female-dominated. There are differences in gender role with regards to mating (birds are, after all, where the "choosy female" dichotomy was first observed), but even there birds can vary wildly from near monomorphic species to ones with extreme sexual dimorphism like peacocks. Regarding toucans, [toucans are more or less monomorphic with regards to gender roles](https://www.scielo.br/j/bn/a/sQQphx6JnrD4wy4t3LBSC7N/?lang=en), both sexes are involved in the care and feeding of offspring, even if the female is the one to actually lay the eggs. ]
[Question] [ I'm trying to work on an elemental scheme for the world that I'm building. I want to start with primary elements and then combine them to create "secondary" elements. The cycle is: Fire < Water < Earth < Wind < Fire Then you could combine a dominant element to its strength in order to create an element able to beat your own weakness. So for instance, since Fire is strong against Air, a Fire user can combine its power with an Air element and make Lightning, which can be used to beat Water, Fire's weakness. So far I've postulated the following combinations: * Fire + Air = Lightning - Beats Water * Air + Earth = Crystal - Beats Fire * Earth + Water = Plant - Beats Air And I can't for the life of me think of a combination of Water + Fire that would beat Earth. I'm also planning on making two "neutral" secondary elements - Lava and Ice which would be Fire + Earth and Water + Air. So it couldn't be either of those. So I ask you guys, **What could be an element that would incorporate Water + Fire and be able to beat Earth?** I've tried searching for inspiration in Pokemon, Naruto, Mysticism and whatever else deals with elements and as of right now the only thing that I could think of is Steam (which quite frankly doesn't give me the vibe that beats earth) and poison (which doesn't give the vibe water + fire). [Answer] **Acid** Acid is liquid which covers your water aspect. It also causes acid burns which can cover your fire aspect. Acids can melt a variety of metals and stone which would make it able to beat earth. [Aqua Regia](https://en.wikipedia.org/wiki/Aqua_regia#:%7E:text=Aqua%20regia%20is%20a%20yellow,platinum%2C%20though%20not%20all%20metals.) can dissolve gold, [Hydrochloric acid](https://en.wikipedia.org/wiki/Hydrochloric_acid) can be used to remove rust from steel, dissolve glass, and is oddly safe for a strong acid. [Sulfuric Acid](https://en.wikipedia.org/wiki/Sulfuric_acid#:%7E:text=Sulfuric%20acid%20(American%20spelling)%20or,formula%20H2SO4.) attacks most reactive metals. [Answer] Steam actually would fit your needs against Earth. You just have to shift thinking a little bit. Normally when you think of Steam, what comes to mind is something like a pot of boiling water, or maybe a tea kettle. What you see in the kitchen doesn't really acknowledge the power of steam though. You get a small clue with a tea kettle. The thing people don't immediately think of is **Pressure**! That pressure turned the machinery of the Industrial Revolution after all. Water, as it turns to steam, expands a lot. By a factor of 1600! That is a lot. So if you compress and direct it, it should blast away at Earth relentlessly. If you can use the pressure that results to project a very fine stream of liquid water, you could even cut stone with it. There are water jet cutting machines that are used to get fine cuts in Granite for countertops partially because it is so hard to cut. So at lower levels, it may not be too effective, but as your mage gains experience and finesse, it could be tremendously powerful. ]
[Question] [ This is my first post on this site. I have done some searching here and elsewhere and was unable to find an answer, so here goes: I'm working on a story that exists both in real-world Earth and a separate dimension, and time elapses at a different rate in the otherworld. I'm building a timeline for both worlds in PowerPoint to track events, history, etc, and it's slow-going because it's basically a manual process in PPT, plus the space constraints of the slide fields are becoming an issue for me. Can anyone recommend software (freeware or licensed are both fine) or other methods where it's possible to build an intuitive parallel timeline that simultaneously tracks 2 different time measurements (Earth years vs. otherworld years) that can also accommodate dozens of overlapping events in each? I've searched all standard sources and most of these programs are built to track a single timeline and not something out of the ordinary like this. Below is a screenshot of a loose version of what I am currently doing, without the actual details of events, just placards to give you an idea. [![enter image description here](https://i.stack.imgur.com/sOVPK.jpg)](https://i.stack.imgur.com/sOVPK.jpg) Any suggestions are welcome, and if there is a different forum or subforum where this would be more appropriate, please let me know. [Answer] Honestly I'd do it in a spreadsheet program. * You can insert / delete cells to move the timing around * the events stay ordered through your edits * It's pretty easy to see what's going as the timelines tighten and loosen: [![enter image description here](https://i.stack.imgur.com/av2CQ.png)](https://i.stack.imgur.com/av2CQ.png) In my fictional future timeline "Spotted Eagle plaque wipes out farmland" occurs in real Earth in the year 2051, but in the parallel universe in the year 903. [Answer] If you have a Surface device with pen input (or Apple equivalent), I can recommend Microsoft OneNote. With it you get * Functionally infinite canvas (in both directions) * Zoom in/zoom out rather far * Copy/paste/move stuff (including data from Office Suite programs natively!) * Drawing tools including rulers, pens, and more * Ability to include pictures, text, PDFs, etc * Sync to multiple devices * Night mode(!) I use it frequently for mind mapping and other brainstorming or planning tasks along with note-taking and I'm rather happy with it. Unfortunately, if your device does not have pen input, a lot of the charm is lost, but it still can act like an infinite powerpoint slide. [Answer] This Reminds me a lot of the timeline functionality you normally see in video editing software. Things like Final Cut, Premiere, etc. It's might be a bit wonky, but what you could do is set your Frame Rate to 10, then you pull your project starting time back to a -1940 seconds, then your Time index should become representative of Earth and your Frame index of Other World. The neat thing is that you can make your events all text elements at different layers so as you drag the time cursor back and forth you'd be able to see everything happening in each world at that time in your preview pane. Best part is that these programs are meant to be infinitely scalable. Sometimes you need to zoom in to see your video frame-by-frame and sometimes you need to zoom out to see a whole 2 hr movie timeline; so, you'll never run out of space to work with. [Answer] Just in case you're still looking, I just found this: <https://paralleltimelines.org/parallel-timelines-intro.html> Apparently it's in concept only, but would be worth keeping an eye on. [Answer] ## npm `timelines-chart` project I don't know if this is related at all to the Hans Henningsen project shared by Wobbler, but there's a javascript-based project called [timelines-chart](https://www.npmjs.com/package/timelines-chart) that might work for you. Casual inspection suggests that you can encode your time series as JSON (which is not difficult) and then this tool will use D3 (one of the best visualization tools around) to draw the timelines. There are three demos linked on the npm page. Here's a screenshot of one: [![Screenshot of timelines-chart project](https://i.stack.imgur.com/6pLxW.png)](https://i.stack.imgur.com/6pLxW.png) ]
[Question] [ Is it plausible to build and maintain a space program without adding to climate change? While obviously there are larger problems in the near term with respect to climate change, I'm thinking about a slightly longer term context with something like [solarpunk](https://solarpunkanarchists.com/2016/05/27/what-is-solarpunk/). If we could reasonably have clean energy dominate(and I understand that is a big if), could we still keep a space program going? I actually think the real problem might be economics. Assuming an eco-energy future, this implies that there would probably be a lower overall standard of living than we currently see in the US, which means there would be less resources to spend on something like a space program. [Answer] # We could do it tomorrow if we wanted to We don't because it's cheaper to do things wastefully than green. Now it's usually cheaper not because being green is implicitly more expensive, but because of [subsidies for oil and gas companies](https://www.eesi.org/papers/view/fact-sheet-fossil-fuel-subsidies-a-closer-look-at-tax-breaks-and-societal-costs), which run into the billions of USD per year, and that they're more established and have economies of scale. If the government decides to quit oil and gas and go green, the space program could survive and, after retooling, thrive even. The biggest cost will be in 2 areas: manufacturing space craft, and getting those space craft to orbit. Everything else I'm assuming can be covered by "put some solar panels on the roof" or "buy local" level of greenness, same as any other office or government department. ### Making space craft green Steel and Aluminium are very energy intensive to make, but that energy can come from a green source, Eg [Germany is making green aluminium](https://reneweconomy.com.au/germanys-cheap-green-energy-keeps-aluminium-sector-healthy-58772/), or be offset by [carbon credits](https://en.wikipedia.org/wiki/Carbon_credit). Also a focus on the re-use of ships (eg SpaceX's auto landing rockets) helps spread this environmental cost over the life of the rocket. Many parts like plastic on the rockets are theoretically recyclable, or derivable from a green source, just it's not ecconomically viable to do so. When your government starts limiting the amount of oil which can be extracted to the point that prices of oil-derived products start to rise, we'll switch to green substitutes as soon as they become cheaper. PLA plastic is a pretty good example, it's common for entry-level 3D printing, that's [derived from corn](https://phys.org/news/2017-12-truth-bioplastics.html). Any exceptions (rare metals in computers, for example) can be covered with carbon credits. ### Fuelling them greenly You just need a lot of energy to get to orbit, that energy needs to come from somewhere, but where that comes from can be green. How much fuel is needed to launch a rocket varies between designs, and I can't find consistent figures (and they're in freedom units rather than metric), but [this link](https://www.nasa.gov/centers/marshall/about/star/et_11.html) says 390 kilogallons of H2 and 145kilogallons of o2 in the external tank. Factoring in the shuttle internal fuel tanks hold fuel too, and the effect of the solid fuel boosters helping at the start, I'm guessing 500:200kilogallons of liquid hydrogen/oxygen should do the trick to get a decent sized rocket to LEO. * 500 kgallon liquid h2 weighs 130 metric tonnes. (<http://www.uigi.com/h2_conv.html>) * 200 kgallon liquid o2 weighs 860 metric tonnes. (<http://www.uigi.com/o2_conv.html>) To produce 1kg of hydrogen by electrolysis costs [about 50kWh](https://en.wikipedia.org/wiki/Hydrogen_economy#Electrolysis_of_water), and you get the oxygen included it that. Excluding pressurisation and refrigeration costs, you're looking at 6.500TWh of energy per space launch. The emissions put out by burning liquid oxygen and liquid hydrogen is - water vapour. It's the ultimate green fuel! ### So how often can we launch? Current solar production (as of 2018) in the USA is [96.1TWh](https://en.wikipedia.org/wiki/Solar_power_in_the_United_States). Using only existing solar installations in the USA, you could do 14 launches a year. If the solar output of china (204,700MW) was channeled entirely into fuel production for space craft launches, they could launch an equivalent rocket every 31.8 hours of direct sunlight. In summer the Chinese could maintain 3 launches per week entirely on green fuel, on their existing solar networks. (And 2 per week in winter) The entire planet has a green energy production output of [2.3TW (combining hydro, solar, and wind)](https://www.irena.org/newsroom/pressreleases/2019/Apr/Renewable-Energy-Now-Accounts-for-a-Third-of-Global-Power-Capacity) If the world unites, we could launch a rocket on green power every 3 hours of full power generation. [Answer] A handful of reusable launches on greenly-produced spacecraft is nice, but let's look a little further forward, to an alternative. If technology advances in some other areas, especially things like lasers and magnetic levitation, a whole bunch of non-rocket spacelaunch opportunities open themselves up for getting things into orbit without burning very much fuel at all. A small (compared to the sum of modern activities) initial carbon-intensive investment would let you build something like a laser-thermal launch system or a Lofstrom loop, which could be powered by renewable sources on the ground and don't entail any greenhouse gases spilling into the air. Once your first set of infrastructure is up, there will inevitably be some environmental cost in mining resources from Earth to put things permanently in space. (Reusable surface-to-orbit vehicles are only part of the picture; you can't exactly bring a Mars colony building back to Earth to recycle it, so that mass is gone forever.) Thus, the immediate priority if Earth pollution is shunned will be to establish self-sustaining space colonies and extract resources from the Moon, asteroids, and so on instead. Drop some space elevator cables to the surface once you've got all that set up (and technology's presumably progressed another few hundred years), and voila, GHG-free human exodus from Earth becomes fully possible for the masses. Feel free to turn the planet into a wildlife preserve or something. [Answer] Many rockets are hydrogen fuelled today because it has a great energy to weight ratio. A great example is the Ariane rocket, which works on hydrogen since the beginning. If we stop extracting it from natural gas and start making it from water with solar or wind generated electrical energy, we're there. Estimates based on today's solar power production are not good: There are large, no, huge desert areas available today for solar which are not yet used. Once hydrogen production takes off, former oil states will use their deserts for energy production. ]
[Question] [ I've read that Roman catapult were made out of iron and I was wondering if it was possible to replace that iron with bronze instead. In a world where bronze is readily available, copper and tin..etc are abundant while iron/steel aren't. [Answer] ## Yes, and they did Not only is it possible, but many Roman catapults specifically were made with bronze and/or brass (not just iron). While bronze may be a bit softer than iron, the ancients were pretty good at work hardening it so that it could have a level of hardness similar to mild steel. Add to this the fact that it was much more resistant to corrosion, there were many cases where bronze may have been preferred for its ease of maintenance. ### The unintended side-effect of removing iron As your civilization develops, your people may also learn to work with nickel. On Earth, nickel is very hard to find in its pure form because it's almost always mixed in with larger amounts of iron, but when you remove iron from the equation, pure nickel will become about as readily available to your ancient civilization as copper. This will give them early access to copper-nickel alloys which will be both cheaper and stronger than bronze. Or, you could have them use bronze-nickel alloys which have very comparable properties to hardened steel. Nickel has a slightly higher melting point but a lower forging point than iron, and a significantly higher melting & forging point than copper or tin; so, its use in the ancient world would likely follow along the same curve as iron. Bronze may be preffered at first due to the difficulty of melting Nickel, but once your civilization gets better at making high temperature forges, you will likely start to see its usage follow a similar path to the iron age. ### Why you would not expect to find this world in our universe > > In a world where bronze is readily available, copper and tin..etc are > abundant while iron/steel aren't. > > > Just so you know, copper and tin are much more rare than iron because of how they are formed. Iron is the densest element that can be created from a net gain fusion reaction in stars; so, it is disproportionately common for its atomic mass because massive stars just stockpile the stuff up more than other elements. Furthermore, it is released mostly from exploding massive stars and white dwarfs which are much more common events than the dying low-mass stars and merging neutron star events responsible for the formation of Tin; so, the likelihood of a world forming with more copper and tin than iron is more or less impossible in our universe. In Earth's history, the bronze age did not happen because iron ore was more rare, but rather that iron has a higher melting temperature which makes it harder to work with for more primitive societies. Most bronze age civilizations already knew about iron, but just lacked the ability to effectively work with it. [![enter image description here](https://i.stack.imgur.com/OJq2U.jpg)](https://i.stack.imgur.com/OJq2U.jpg) [Answer] In a word, Yes, they can be. It is not necessary however to use metals at all, just an advanced 'catapult'. Consider the trebuchet - only wood, rope, weight and gravity. Highly effective, very low overhead in materials, many could even be constucted on site during a seige. See diagram: [![Simple Trebuchet](https://i.stack.imgur.com/ZASmV.png)](https://i.stack.imgur.com/ZASmV.png) ]