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[Question]
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I’m creating an Earth-like world where the sun appears blue to people from the planet’s surface. I think I’ve narrowed down the cause of this effect to the presence of 1 micron particles in the atmosphere, which would scatter and absorb the longer wavelength red light from the planet’s sun. This would mean that people on the surface would primarily see the blue light waves from the sun, making it appear blue. So now that I’ve explained my planet’s blue sun, my question is, would this scattering and absorption of the red light in the atmosphere harm Earth-life forms. In other words, if lifeforms just like the ones on Earth lived on this planet, would the difference from the scattered/absorbed wavelengths of light kill them? Here’s a few points of clarification:
* By Earth-life, I mean not just animals but plants and vegetation as well.
* The forms of Earth-life I’m referring to are lifeforms that rely on sunlight. I’m not concerned about cavefish, etc. Any creatures or plants that could actually be negatively affected by changes in sunlight.
* The temperatures are similar to those on Earth.
* This planet’s sun is similar to our own. It isn’t a blue star, it only appears blue from the planet’s surface.
* I think I should also clarify that some red wavelengths of light are still reaching the planet, it’s just a small enough and scattered enough amount for human eyes to perceive the sun as blue.
[Answer]
**Let's invite an expert's opinion**
[Dr William Stiles](https://www.aber.ac.uk/en/ibers/staff-profiles/listing/profile/wvs/#) of Aberystwyth University [wrote the following](https://www.vertikit.co.uk/the-influence-of-different-light-wavelengths-on-plant-growth/) (emphasis is mine):
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> Light is an essential component of plant development and is a key driver of plant physiology and morphology. Light is crucial for photosynthesis, the chemical reaction that fixes CO2 for the purposes of food production, but it also acts as an environmental prompt, informing plants about the world in which they exist. Plants detect information from incoming light using sophisticated multi-functional sensory proteins called photoreceptors. Plants possess at least five classes of photoreceptor: phytochromes, cryptochromes, phototropins, Flavin-binding F-box proteins, and UVR8. Actual signalling pathways, and the interaction between different receptors, are complex, but in essence **phytochromes perceive red and far-red light, cryptochromes perceive blue and UV-A light, phototropins and Flavin-binding F-box proteins blue light, and UVR8 perceives UV-B light.**
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> Light from within the visible spectrum drives photosynthesis, particularly light from within blue and red wavelength ranges, but the potential for photosynthesis will be governed by the amount of energy available in the form of photons that a plant can absorb. Light intensity, and its potential for driving photosynthesis, is referred to as the photosynthetic photon flux density (PPFD). **The higher the PPFD, the higher the potential for photosynthesis.** Plants absorb light energy via the light-absorbing pigment chlorophyll. Chlorophyll appears green as it absorbs all visible light except green wavelengths, which are reflected. **Chlorophyll A and B absorb red and blue light strongly, and as such these wavebands have been considered the only portion of light that truly matters for plant production. However, increasingly it is recognized that plants make use of all available light to at least some degree,** including green light, and that presence (or absence) of different wavebands influences plant development.
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> Each of the wavebands of the light spectrum, and their relative proportion in the available light, will trigger a response in the plant. The different wavebands are:
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> ***Red light (600-700 nm)*** – light from the red wavelengths is the main driver of vegetative growth. This means more leaves and more biomass. But growing in the absence of other spectra may result in a phenomena referred to as red-light syndrome, where leaf photosynthesis can become impaired. Without the presence of blue light, the form or morphology of plant tissues may also result in unfavourable growth profiles, where plants become stretched and tall, with thin leaves, which is a typically unfavourable growth profile. It may also mean plants cannot utilise all available light energy, leading to overall inefficiency. Overall, red is the most important wavelength for plant growth and development, but not in isolation.
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> ***Blue light (400-500 nm)*** – light from the blue portion of the spectrum has a large effect on plant morphology. It can increase the ratio of root to shoot in plant development, promoting root growth and plant compactness, which has certain implications depending on production goals. Blue light also promotes more stomatal opening, which means more stomatal conductance and gas exchange. This is typically considered favourable from a plant health perspective but may result in greater humidity potential, which is a consideration for controlled environments. Blue light is absorbed readily by plant photoreceptors, and is an important factor in plant environmental perception. For instance, increasing the percentage of blue light will convince plants that there is more available light overall, which will change plant behaviour.
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> ***Green light (500-600 nm)*** – green light is weakly absorbed compared to red and blue wavelengths, but is increasingly recognised as important for overall photosynthesis potential. Green light is reflected and scattered within leaves and the canopy, which increases the potential for total absorption. Green is particularly important in dense-growing scenarios where there is a large amount of shading, as it drives photosynthesis in lower or shaded leaves. Green light also affects morphology via the green to blue light ratio. This acts as a signal to indicate shade conditions, informing the plant and leaf of its position in the canopy, initiating growth behaviour associated with shade avoidance. This can include extra growth or stretching of the internode and leaf length, and the angle of the leaves may also change to capture more incidental rather than direct light.
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> ***Far-red (700-850 nm)*** – this portion of light is referred to as super-visual, as the majority of this waveband is outside the visible portion of the spectrum. Far-red is not considered conventionally photosynthetically active and it only weakly drives photosynthesis, but adding far-red will change how plants grow as this light is absorbed by phytochrome photoreceptors, which are involved in the regulation of leaf expansion, flowering, internode extension, and the partitioning of resources between organs. Far-red will also have the opposite effect to blue light on root to shoot ratio, resulting in higher shoot to root distribution. Yet, as with all elements of the light spectrum, there is a balance to be struck between a beneficial amount of far-red light and too much. Plants grown under high levels of far-red light will appear tall and stretched, with lower chlorophyll content resulting in yellowing of the leaves, which is perhaps unfavourable from a marketability perspective. In addition to direct effects, the ratio of red to far-red light is also an important mechanism for governing plant responses. Far-red penetrates the canopy more than red light, so plants receiving a higher amount of far-red relative to red will interpret this as a shading effect, and increase shade avoidance responses such as increased upwards growth.
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> ***UV spectrum (100-400 nm)*** – UV light is also outside of the PAR wavelengths, but this light will still affect plant development. Plant responses to UV-A light are similar to blue light. UV-B is higher energy and has its own photo receptor in plants, called UVR8. Adding UV-B to the spectrum will change the morphology in ways which are not considered essential for survival, but which may affect the potential for production. For instance, under UV-B light plant cuticles can grow thicker, making the plants generally more robust, and UV-B exposure will positively regulate stomatal development, but hypocotyl and petiole length may be shorter and rosette leaf expansion may be impaired. Secondary metabolite production is also higher under UV-B, which is typically a favourable response, particularly for production systems focussing on pharmaceutical production. UV-C is not believed to be directly perceived by plants, but it can be highly useful for the control of pests and disease in controlled environments.
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**Summary**
Light across the so-called visible spectrum is used by plants — not just the red spectrum. Losing the red spectrum would have a detrimental affect on the plants, and therefore any animals dependent on the plants. But would your world kill the plants?
**NO**
Blocking and/or scattering enough light to let the sun appear blue to human eyes ***does not mean*** that no red light is striking the surface. There would still be sufficient red light to promote plant growth and, obviously, plenty of the other spectra of light to positively affects plants.
*As a quick aside... if you did block all the red spectra light, that means that NOTHING on your planet would appear red because there's no red light to reflect. Chalk that one up to the Law of Unintended Consequences, so it's good that some red spectra light is getting through.*
However, and as a viable and interesting part of your story, plants would suffer. Or, perhaps said better another way, they would not be as prolific under the conditions you propose as they would be on Earth. What that means is that they'll need to adapt. Human history and science has demonstrated that biology is *really, really, good* at adapting. It will take some time (if not helped by intentional human effort), but I don't see a reason why the plants wouldn't be adequate in the beginning and fine over time. (OK, thousands if not millions of years worth of time... but still....)
**What about the animals? Tell me about UV...**
I don't think your animals have any problems at all. The presence of red-spectrum light doesn't mitigate the effects of UV light. It could be true that if you require a brighter star in order to have the same luminosity on the surface of your world as we do here on Earth, that would up the UV. But that also ups the heat and a lot of other things (like upping the solar wind...). That means plant and animal life are threatened for reasons *that have little to do with the question you asked.*
If, indeed, the sun is "similar to our own" in that the star's output is similar to Sol's output, then you have no problems at all. The world would be (frankly, imperceptibly) dimmer and the star would look blue, but that's it. Nothing would die.
*Now, a particulate count high enough to achieve what you're proposing, depending on what those particles are... that could kill everything. Or at least give everything with lungs and sinuses the worst case of chronic hay fever ever heard of. But I'll leave that issue up to you.*
[Answer]
I don't think any of the answers have addressed this point yet: if the effect is caused by scattering it will not actually stop much red light from reaching the surface. (Some will be scattered back into space, but not much.) The sun will appear blue but the sky will appear bright red, and the red light from the sky plus the blue light from the sun will add up to white.
The opposite happens on Earth when the sun is low in the sky. Direct light from the sun appears yellow, but shadows appear bluish because they are lit by blue light from the sky. A white piece of paper in indirect light will still appear white.
This means there won't be any problems for photosynthesis on your planet at all. Plants will be getting the same spectrum of light they get on Earth, it's just that some wavelengths will be coming from different directions than normal.
I leave you with this photo of a sunset on Mars, taken by Nasa's Curiosity rover. Mars' atmosphere scatters red light. You can see the blue light from the setting sun as well as the red sky further away from it.
[](https://i.stack.imgur.com/UEk4x.png)
[Answer]
Scattering will not turn light bluer. Smaller wavelengths scatter more than bigger ones. Absorption, in which your atmosphere works as a kind of blue-pass filter, might be possible (if you can get the chemicals or particulates that are absorbing the redder spectra to stay in the upper atmosphere somehow), but will probably kill everyone, because:
1: A blue-pass filter is a greenhouse effect generator. The energy from incident red light is going to still get to the planet as IR, and up to half of the re-radiated IR from the planet's surface is going to come back to the planet, since the blue-pass filter will absorb it and re-radiate it in all directions... Things are going to get really, really hot.
2: As Nosajimiki notes, you'd need to increase the star's brightness if you want terrestrial plants that need full sunlight to grow - which would have the noted UV hazard effects, but would also make (1) even worse.
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Below: a response from when the question indicated a blue star, not a blue-pass filter.
Terrestrial surface life would have trouble. Plants and microbes would fare worse than animals, who can have nonliving shells or fur between them and UV, or can hide under things during the day and come out at night. UV is harmful because it is readily absorbed by DNA, not because it penetrates deeply (hence burns and skin cancer, but not radiation sickness).
Subterranean life would be fine. UV does not penetrate rocks.
Aquatic life would be fine below a depth of several meters, because UV is absorbed more by water than visible light; however, life that lives at the surface of the water would have the same problems as on land.
A much bigger problem is **time**. Blue stars live fast and die young - so young they may not even have planets that have swept out their orbits and cooled off enough for liquid water, let alone billions of years after that for abiogenesis and evolution. You might be able to get away with having a planet captured from another, much older star system, although I'd guess that the chances of that happening in a way that leaves anything macroscopic alive are vanishingly small.
[Answer]
My apologies for tossing off a quick answer this morning. Here's more details.
Photosynthesis is generated at multiple wavelengths by two different forms of chlorophyll. Chlorophyll A has its peak absorption in the 429nm (almost purple) and 659nm (red-orange) wavelengths. Chlorophyll B has peak absorption at 455nm (indigo) and 642nm (orange). Chlorophyll B doesn't actually complete the step from light to sugar, it just supplements A's range of energy. If there were enough blue light, the plants could still generate enough energy to survive.
[](https://i.stack.imgur.com/GhRHh.png)
The real problem you will find is that plants use red and blue light for different purposes. This isn't a matter of what it CAN receive, but how it's bred to use it. Blue light is used by plants to encourage fast growth, longer stems. Red light is used to make thicker stems and induce blooming. This is due to the increased prevalence in red light during the autumn months.
Plants uses red light as a signal to maintain its annual cycle in the same way we use blue light to maintain our diurnal cycle. Thus, you would have issues with plants never blooming (or fruiting), and not knowing when winter was coming in the temperate zones. I believe this would lead to extinction of many species.
[Answer]
## Different setups create different solutions.
There are a few basic ways your hypothetical setup could exist.
For starters, either the upper atmosphere is reflecting shorter wave lengths, or it is absorbing them. This is an important distinction because if it is reflecting them, it means your planet needs to be much closer to the sun to get Earth like surface temperatures from only the short wave length light. If it is absorbing them, then you can have the same orbital distance, and your lower atmosphere can maintain a similar temperature with less light actually reaching it.
The other possible variable is if you are filtering just visible light in the 700-500nm range, or if you are filtering all wave lengths shorter than 500nm. Since the goal is to kill Earth life, I will assume you are filtering everything shorter than 500nm (green, red, infrared, microwave, etc.) since this will produce a more extreme effect.
### If you are reflecting the longer wave lengths
For this to work, the sun has the same apparent magnitude as ours, but the sun is much closer to the planet such that it is the same amount of energy reaching us, but only from short wave lengths. For a filtered light to keep the planet warm, it needs to carry a lot more short wavelength light. So, for the star to be the same as our sun, it must also be closer.
Infrared, red, and green light collectively make up about 81.25% of the sun's total radiation with ~10.75% being in the blue spectrum and the remaining 8% being UV through gamma. This means that the blue, UV, and Gamma Radiation of the sun will need to be about 5 times as intense to maintain the planet's surface temperature. That said, the blue spectrum makes up 25% of visible light; so, it will also be 25% brighter outside despite the missing red and green light.
Despite seemingly tolerable levels of heat and light, the UV radiation would sunburn us several times as quickly, we'd develop skin cancer very easily, the blue light would damage our retinas making us go slowly blind, and plants would whither and die. Terrestrial desert life might be able to survive in this planet's rainforests where the heat is high enough, but there is little direct exposure to the sun... but this would depend on if we can eat the local flora since growing our own agriculturally useful plants anywhere they would get enough light and not too much UV would be very difficult to balance.
### If you are absorbing the longer wave lengths
In this scenario, you get the same heat. With the red and green light filtered out, you would only get blue light photosynthesis. While blue light has a higher [RQE](https://www.canr.msu.edu/news/green_light_is_it_important_for_plant_growth) than green light, it is lower than red. This should all balance out to being about equivalent 25% of normal photosynthesis.
While this might be enough for certain forest floor plants to survive, if planted in direct sunlight, it would significantly reduce how quickly and fully any plants grow which would make growing enough food for humans to survive very difficult.
This would be a less deadly option than reflection, but it would certainly make the planet difficult to survive on as well.
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[Question]
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So, having rejected mind uploading in their quest for immortality, the people of my worldbuilding project now seek to develop brain transplanting.
The main problem is immunorejection; if you simply chucked a brain into an donated body, then said body’s immune system will attack it and the brain will die, if Robert J. White’s attempts are anything to go by, within ten days.
So, then I considered having the body be instead cloned from the stem cells of the original, (with some genetic modifications to prevent it growing it’s own brain). Since the brain and the body will therefore be genetically identical, will this prevent the body’s immune system rejecting it?
[Answer]
No, not if the body was cloned.
The white blood cells/lymphocytes in the body would find the proteins in the brain to be [histocompatible](https://en.wikipedia.org/wiki/Histocompatibility).
The lymphocytes work by detecting proteins, and proteins are made by the DNA. "Clone" means "identical DNA" which means "identical/compatible proteins".
[Answer]
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> *"Would a brain transplant suffer immunorejection if the new body was cloned from the original?"*
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No, thrice no, definitely no and indubitably no.
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> *"The main problem is immunorejection"*
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Nope, there's not even the smidgen of a hint of a faint suggestion of a problem of that if you're using a cloned body.
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And as it happens theres not as much of a problem with a brain transplant into any old random non-cloned body as you might think as practically all of the immune system avoids going in there .. it's a no go zone for much if not most of our bodies defense systems against foreign objects which is why so many viruses hide in nerve tissues to avoid our bodies defenses .. so if there's anything you can transplant and expect a relatively minimal immune reaction from the body then that's it.
Sure the immune system ***can*** attack the brain .. encephalitis is a thing .. but not **all** of it can effect the brain which will reduce the types of immune suppressant treatments you might need and also allow some elements of the immune system to safely remain active to protect you from infection.
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But that aside allow me to suggest a small additional procedure, inject a very small number of pig stem cells into the sole of one foot of the developing embryo of your people, done correctly at the right stage of development it will have no effect on the developing baby except allowing it to accept any and all transplants from a clone of that pig with no immune reaction at any later point in life .. it essentially tricks the developing immune system as it calibrates itself into recognising the pig DNA as its own .. keep your original body healthy longer with any repairs or spare parts it might need.
Which unless you have a way to fast track your clones or you start one for everyone as soon as they're born and everyone always has a spare adult clone on hand is something you may need to keep you going while you wait for your clone to grow enough for your brain to fit in its cranium.
Incidentally, a useful little trick to use if you want to be someone else in your next body that, you can use it to *'inoculate'* a new clone of anyone you like against rejecting your tissues, man, woman, even reasonably compatible animals (that provide your brain's nutrient requirements in their blood, who's bodies operate at an appropriate temperature, etc), you can be them all if you want.
[Answer]
## Rejection may be a problem
The issue lies in this statement:
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We don't understand everything there is to know about how the immune system works, but we do know that mammal immune systems starts off in early life more or less dormant as it uses the mother's immune system to keep it safe as it "learns" to defend your body from infections based on the anti-bodies the mother gives it. This means that it is possible that you are not born with an immune system that understands what your body looks like, but instead figures out what normal looks like during this early "safe mode" stage of development.
So, if you were to clone a body that never had a brain in it, then it is possible that the brain, once introduced, would be identified as a foreign object.
But more importantly, **your clone body NEEDS a brain**. Holoprosencephaly(HPE) is a developmental defect in which the brain fails to fully form. While a fetus can survive until birth from mild forms of HPE where only the frontal parts of the brain fail to develop, in more severe cases where lower brain function fails to develop properly, the fetus dies in utero despite the body getting all the nutrients it needs from the mother. This is because your brain does more than just conscious thinking, it is responsible for regulating your other vital organs. If a fetus does not have a working brain, then it does not have a working heart, lungs, etc. and it will spontaneously die when those organs start to try to form.
Instead, it might be preferable to make a perfect clone of the host (brain and all), and to simply put the body into a forced comma at as young of a stage as possible. Then you simply remove the un-needed bits when the time comes.
[Answer]
There are two possible though *extremely* unlike opportunities for rejection.
First:
There are some things that can modify genetics. Radiation. Some chemicals. Some viruses.
If the subject had been exposed to these at a very young age, his brain might have a significant portion of its mass of a different genetics to the remainder of his body. His immune system grew used to it slowly as he grew up. A fresh new immune system cloned from his original DNA would not have had time to get used to the "foreign" DNA.
This is unlikely at multiple-stupidly-unlikely level. First the DNA modifying event had to occur and not kill the subject. That's unlikely on its own. Second, the immune system has to not tag the new material as foreign and kill it. Third, the modified material has to be in the brain only. And fourth, it has to be such that it does not turn into cancer and kill the subject outright.
So, to summarize, this one is daytime-TV-soap-opera unlikely.
Second:
The subject is a chimera. This happens very rarely indeed among humans that survive to adulthood. As explained on the TV series House, it can happen when fraternal twins "snuggle up" shortly after fertilization. It means one individual can have two sets of DNA. The immune system of the individual develops with both sets present so it is possible for an individual with this situation to grow to adulthood.
However, a cloned body be from one cell and so would not have this double DNA to practice its immune system on. So if the brain was from one set of DNA, and the portion cloned for the fresh body was from the other, then the brain could be rejected.
This is also multiply-stupidly-unlikely. The condition is fairly rare. The brain being one DNA and the cloned cell the other is 50-50. And getting rejection from a sibling is not automatic.
[Answer]
## Wildly unclear, but you can probably safely decide either way.
If "clone" is shorthand for "exact copy," then almost certainly not.
If "clone" means identical DNA, then it's likely okay, but not at all guaranteed.
The issue is that you have a whole bunch of stuff in your body that isn't strictly based on DNA. The obvious example is immunities: you developed an immunity to chicken pox (or whatever) by exposure to it. There are genetic factors that make you more or less fit to survive chicken pox (or bubonic plague, or whatever), but the actual environment you've lived through has a strong effect on your immune system.
So: will the clone body reject a genetically identical brain? *Probably* not. It avoids most of the largest pitfalls. But at the same time, if your original body was bitten by a tick and had a meat allergy (or whatever) your new body might be shocked enough at this to give your brain a bad time (and your brain is not a good place to have immune/allergy reactions going on!).
Ultimately, your probably fine fudging it whichever way make sense for your world. Rejections might be rare or common, but it's probably not an all-or-nothing proposition regardless.
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[Question]
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There exists a polymerization spell that allows distinct animals to combine with each other, creating an entirely new creature. The beasts in question are held in transumutation circles linked by ley lines and surrounded by specific ingredients to make the spell work. Ingredients are specific to the creatures in question, or setting will go wrong and you will end up with a messy, organic blob.
After many hours of ritual chanting, the summoner finishes the spell with the phrase "FUSION!! HA!!, which combines the animals. These creatures are not like tigons or ligers, beings that have numerous biological problems due to their unnatural situation. Instead, it is a true fusion of two or more creatures, a symbiotic joining that gives the creature the best traits of its parents.
The chimera, such as a sphinx, a sharktopus, or a piranha-conda, is a fusion of the components of both creatures to create a unique biological system. Due to this factor, they are unable to breed with either species, as the resulting animal looks completely different from both parent races. However, it has also been discovered that chimeras of the same type cannot breed with each other either. This makes the business of making these things expensive, as they must be custom- built each time.
How could chineras be prevented from reproducing with each other?
[Answer]
**They can breed. They just don't breed true.**
Start with Mendel and his peas. There is more going on in the genome that is apparent in the phenotype. When you cross 2 animals apparently the same, you will get some traits in the offspring that were present in neither parent.
[](https://i.stack.imgur.com/F9N8G.jpg)
<https://www.slideshare.net/melindamacdonald/mendel-and-his-peas-30447902>
This is why first world farmers don't save seed since the 1930s - hybrid seeds don't breed true.
But you can riff on this with the magic angle. If you dig into the code used to make any given software product you can find artifacts of its prior applications. Coder credo: "use old code". It is field tested to work and it is easy to copy paste. So too the magic underpinning of your hybridization magic. In the magic are relics of its prior uses hybridizing other animals, and possibly other more distantly related applications.
When you cross 2 magic hybrids, in the second generation your creatures will manifest aspects of their "magic genome" that was not evident in either parents. There will be aspects of other prior hybrids. There may be manifestations of necromantic or regenerative magic. There might be a summoning. It is already enough work to make a hybrid using the magic you have; this magic is cumbersome and annotations when they exist are cryptic and hard to decipher: either by intent, incompetence or extreme antiquity of the annotators.
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No result is fine and realistic. In real life, defective code (or mutant gene) probably just will not run/work. Much more interesting is when bad code / mutant gene gives an unexpected result. Maybe still usable. Maybe a total disaster. Maybe much better than what you expected. That is how real genetics works.
[Answer]
Separate DNA.
The DNA of the creatures remains separate. While the immune response of each creature will no longer murder these alternative DNA cells (strongest traits of the parents!) It also means that when creating sperm cells the DNA remains separate.
Example, in the case of 3 creatures being merged, the sperm created would consist for 33% out of each individually added creature.
Theoretically they could still reproduce with their original component creatures, but which creature is going to do that? And it will not produce a chimera, but a single one of the original species, assuming the wrong DNA doesn't merge with the cell first and cause the egg cell to fail. So in the end it wouldn't be an efficient use of your time to let them breed like that.
[Answer]
**Magic?**
The magic that binds the Chimera together also prevents them from breeding. The original component animals weren’t sterile, but the resulting creature is (because of the transmutation process).
If you want a slightly more involved (and messier) reason:
**Magic!!**
The magic that binds the Chimera together is linked to their life force. When creatures breed, their life forces intermingle. The Chimera magic is powerful, but delicate, so mixing two chimeric charms via the act of breeding tends to result in spectacularly unintended side effects and apprentice summoners cleaning globules of the two (now ex) Chimera off the walls, the floor and the ceiling.
Either way: incompatibility between the magic and the process of breeding is what prevents the breeding.
[Answer]
**Each time you make a chimera you are creating a new species**
Some simple people think that for making a basic sphinx you only need to mix a human and a lion. That somehow you mix both and the result will always be a sphinx. Those that hold such views reveal their uttermost ignorance of the art of chimeracraftship. For it is clear for even the most dumb, that when mixing a person with a lion you could end up with a creature having the head of a lion and a body of a human as much as a one with the head of a human and the body of a lion. Or a lion with an additional pair of human arms, or a person with lion tail, the possibilities are countless. And that is only taking into account the parts of the creatures that will be mixed.
The reality is that the floor lines, the ingredients put around them, and even the chantics themselves are part of the chimeras. They are not some "instructions" for how should the animals mix, but actually become part of them.
Now, it is true that the effect of some ingredients doesn't a big influence on the creature, for instance having a greater number of corn grains will generally just result in a more yellow fur in the resulting sphinx¹ and a proficient summoner is usually able to obtain a decent result even with suboptimal ingredients (like fruit non being fresh), at the cost of a longer process and putting more of its power into the transmutation.
But the fact is that everything taking part on the invocation, from the disposition of the ingredients, the exact intonation, rhythm and pauses used by the summoner, to the original themselves take a crucial role in the forming of the new species. Thus, even though they are all classified as sphinxes, each and every one of them is its own specie, as they have their own lineage (which will only ever have a single individual, sadly).
A few chimera creators have done some experiments trying to create two distinct individuals from the same species, usually by having two summoners build the same type of chimera at the same time, with the same ingredients and using pairs of animals of the same litter. So far with no success.
On the other hand, this is mostly an academic question with most summoners just accepting as a fact that the resulting animals will not be able to breed, and very happy it is this way, given the large profits they make from each chimera they create. Actually their guild would get *very angry* with anyone that proved otherwise.
Finally, note this is completely consistent that even on the [Creation](https://en.wikipedia.org/wiki/Genesis_creation_narrative), Women and Men were not created separately but one from another, which for chimeracrafters is evidence it is not possible² to create on different acts two individuals of the same species (ie. two individuals that are able to breed between themselves).
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¹ The creation of sphinx by the Ancients show us that they were even able to create sphinxes even without corn, although no corn-free recipe is known today.
² At this point this usually rises a theological discussion on God's omnipotence when there are educated listeners in the room, which leads to their official position stating just that doing so would be *extremely complicated* and doing things this other way was a much more simple and elegant action from our Creator.
[Answer]
# The Gods determined that taboos must be broken.
* Just as in Greek mythology, the Sphinx - `Σφίγξ`- was most often depicted as female with a human head, a lion (or other great cat) and wings:
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In Egyptian mythology it would have been without wings and male.
* Such [archetypal](https://en.wikipedia.org/wiki/Archetype) creatures have been common in [mythologies of the world](https://en.wikipedia.org/wiki/LGBT_themes_in_mythology) since these creatures were first known, many are transgender, many are homosexual or lesbian and thus unlikely to procreate.
* The [Sirens](https://en.wikipedia.org/wiki/Siren_(mythology)) of Greek Myth were always depicted as female, seeming to have but one purpose, to lure sailors to their death on the rocks (for who knows what purpose - spiritual energy, food, maybe out of spite for their loneliness). Female spirits.
* Centaurs (human/horse) and Minotaurs (human/bull hybrid) were most often portrayed as male only, these [liminal creatures](https://en.wikipedia.org/wiki/Liminal_being) symbolizing the untamed aspects of our social nature. Male spirits.
To sum-up: each creature has a purpose in the mind of peoples, each reflects a certain aspect of either the [female psyche](https://en.wikipedia.org/wiki/Feminine_psychology), or the [male's](https://en.wikipedia.org/wiki/Masculine_psychology) - most often to do with the taboos of that society, most usually centered around death and sexual/social boundaries rather than normal reproductive life.
The Gods made them so to reflect humanities's foibles, weaknesses, desires and fears back to them (or perhaps to reflect [their own](https://en.wikipedia.org/wiki/LGBT_themes_in_mythology)) - often setting people traps to fall into to their shame and death (The Gods also made it possible for *only* such creatures as fulfilled this requirement to exist - all others are forbidden).
[Answer]
Oh but they can breed. They just have the same problem as modern day bulldogs: they just don't have a shape that favours a tight fit.
Or do you really picture a couple of these ones coupling?
You've never seen sex capable chimeras for the same reason that Mosanto's crops are sterile: there is actual profit to be made if your customers always have to come back to you for more.
[Answer]
**Polymerization is an animal grafting spell**
[](https://i.stack.imgur.com/3VVT9.jpg)
To reduce the complexity of creating a chimera, we don’t deal with mixing DNA. Instead, we only include the parts of the animals we need, which we then graft onto the ‘main animal’, similar to a transplant. The main animal will keep everything it normally has, but have added features from the other animals.
As to why we need the exact ingredients and leylines ? They prevent [**rejection symptoms**](https://www.webmd.com/a-to-z-guides/life-after-transplant-signs-rejection) caused by the grafting. With the wrong ingredients and leylines, the animal’s complete body will suffer from extreme rejection symptoms and break down into a blob of flesh, because mixing so many body parts from completely different animals is no joke.
By grafting only the features we need, such as a spider’s fangs, snake head, goat hooves, etc, we reduce the risk of rejection. Also, because we graft the parts onto the animal, and the medicine is preventing rejection, *the base DNA of the main animal does not change*. If it mates, all we would end up with is the main animal cubs, and none of the grafted features of a chimera. The DNA not changing has the added benefit of any layman with the spell and ingredients being able to carry out the polymerization, and not need a biology degree in magical genome sequencing and splicing.
**Why graft features: sexual organs add too much complexity**
To create a perfect chimera, and sufficiently lower the risk of ending up with a blob, we should never graft sexual organs.
This is because we are probably looking to create a chimera from animals that don’t mate in the first place; snakes and lions have completely different mating systems and habits. Even species that are both mammals can [‘have a good deal of diversity in their sexual organs’](https://en.m.wikipedia.org/wiki/Reproductive_system). In terms of habits, some snakes, insects, etc, even [*eat their mate after reproduction*](https://en.m.wikipedia.org/wiki/Sexual_cannibalism). A struggle between chimeras trying to eat each other is the last thing we want to deal with.
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[Question]
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**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.
How small could our Sun be and still "burn" with nuclear fusion and emit the same spectrum of light and other radiation as the real Sun does?
*Edit:*
The goal is to have a small sun inside a huge vessel, such as an O'Neill cylinder.
[Answer]
# Black body radiation
The Sun is, approximately, a black body. That means that the light it emits follows a particular spectrum according to [Planck's law](https://en.wikipedia.org/wiki/Planck%27s_law), with the shape of the spectrum determined solely by the Sun's surface temperature. In particular, the wavelength of peak emission can be found through [Wien's law](https://en.wikipedia.org/wiki/Wien%27s_displacement_law), which is also a function of temperature. Therefore, if we want our new star to emit light just like the Sun does, we need to keep it at the same temperature as the real Sun - about 5800 K.
Furthermore, spectra are much more complicated than simple plots of the Planck function. Emission and absorption lines dot a star's spectrum, and these lines depend on the temperature and composition of the photosphere. Various electron transitions happen at different rates at different temperatures, and even shifts of a few hundred Kelvin can produce noticeable changes in spectral line types and shapes - if your spectrometer is good. Even surface gravity plays a role. This restricts our options to Sun-like stars, as only stars with near-solar composition and temperature will produce the same spectra - globally and at particular wavelengths.
On the main sequence, there are [some simple scaling relationships](https://astro.uni-bonn.de/%7Enlanger/siu_web/ssescript/new/chapter8.pdf) between mass, radius, temperature and luminosity:
$$L\propto M^3,\quad R\propto M^{3/7},\quad T\propto M^{4/7}$$
assuming the proton-proton chain reaction is the main source of energy, which is the case. If we want to keep the temperature constant, we need to keep the mass constant, and thus keep the radius constant. Therefore, no main sequence star can be significantly smaller than the Sun and still have the same temperature.
(As I mentioned before, the composition of the star does matter; in fact, according to something called the [Vogt-Russell theorem](https://en.wikipedia.org/wiki/Vogt%E2%80%93Russell_theorem), the mass and composition of a star uniquely determine its properties and evolution. This means that the exact form of the relations above does vary between stellar populations - in part, relying on the mean molecular mass $\mu$ - but this still will not make a significant difference here.)
# Options for a Sun-like star
We *could* look at subdwarfs, low-metallicity stars that are dimmer than main sequence stars. They're not common, but they exist, lying immediately below the main sequence on the Hertzsprung-Russell diagram. All other G-type stars are either on the main sequence, and thus fairly like the Sun in size, or off the main sequence, as giants or supergiants. Therefore, our options are either G-type subdwarfs or main sequence stars that are slightly cooler than the Sun:
* [Tau Ceti](https://en.wikipedia.org/wiki/Tau_Ceti), a main sequence star, might be a good choice; it has a temperature a few hundred Kelvin less than the Sun, and is approximately $0.79R\_{\odot}$ in size ([Texeira et al. 2009](http://adsabs.harvard.edu/abs/2009A&A...494..237T)).
* [Mu Cassiopeiae A](https://en.wikipedia.org/wiki/Mu_Cassiopeiae), a subdwarf, has a similarly slightly-cooler temperature and again a radius of about $0.79R\_{\odot}$ ([Boyaijan et al. 2008](http://adsabs.harvard.edu/abs/2008ApJ...683..424B)).
Another star I considered is Groombridge 1830. Like Mu Cassiopeiae, it's a borderline G-type subdwarf, but is about 1000 K cooler - too far from the Sun in terms of temperature.
Now, we can see from above that temperature and radius are related by $R\propto T^{3/4}$. Therefore, if the lowest-mass G-type main sequence star has a temperature of about 5,300 K, it should have a corresponding radius of
$$R=\left(\frac{5300\text{ K}}{5800\text{ K}}\right)^{3/4}R\_{\odot}\approx0.93R\_{\odot}$$
which is a bit higher than the radius of Tau Ceti, despite having the same effective temperature. This is, of course, because our scaling relationships are inexact, but simply good approximations.
# Low-mass stars and true lower limits
You won't find a star small enough to fit into an O'Neill cylinder - at least, not one that formed by natural means. [EBLM J0555-57Ab](https://en.wikipedia.org/wiki/EBLM_J0555-57), a small, late-type red dwarf has a radius 0.84 times that of Jupiter ([von Boetticher et al. 2017](http://adsabs.harvard.edu/abs/2017A&A...604L...6V)) - likely too large for your purposes. Bodies smaller than that are likely too low-mass to fuse hydrogen, and would instead be brown dwarfs. Of course, EBLM J0555-57Ab is also likely cool, with a surface temperature far below that of the Sun.
Brown dwarfs - many of which fuse deuterium - are not true stars, and are usually cool, with typical temperatures around 1000 K, producing spectra much different from the Sun's. Some exoplanets may be much hotter than this, with surface temperatures comparable to those of many stars (see e.g. Kepler-70b, with a surface temperature of about 7000 K as per [Charpinet et al. 2011](http://adsabs.harvard.edu/abs/2011Natur.480..496C)). However, those bodies are only hot because they're irradiated by the stars they orbit; on their own, they would not generate that much heat.
# White dwarfs
There *is* a possibility I had completely forgotten about before: a white dwarf. Many white dwarfs are hot, with temperatures up to about 100,000 K or so. However, they do cool - albeit slowly, as they have small surface areas. This cooling takes a long time, but some white dwarfs have become cooler than the Sun. [WD 0346+246](https://en.wikipedia.org/wiki/WD_0346%2B246) is a famous case, with a surface temperature of about 3900 K ([Hambley et al. 1997](http://adsabs.harvard.edu/abs/1997ApJ...489L.157H)).
This implies that white dwarfs with temperatures like that of the Sun do exist; moreover, they're small. The same group measured WD 0346+246 to have a radius roughly that of the Earth, which is extraordinary - certainly less than that of EBLM J0555-57Ab. The problem, of course, is that white dwarfs don't undergo fusion. Indeed, the degeneracy of the matter inside a white dwarf means that fusion reactions are unstable, and can lead to novae and Type Ia supernovae.
[Answer]
The mass of a star is directly related to how hot its surface is, which in turn, is responsible for the wavelengths of light it emits (This is called Black-Body Radiation).
As a main sequence G2V star, the sun has a surface temperature of 5778 K. A smaller main sequence star will be cooler and therefore redder. A larger star will be hotter, and therefore whiter.
The only stars that will emit the same wavelengths as the sun are those that have the same mass.
<https://en.wikipedia.org/wiki/Main_sequence>
<https://en.wikipedia.org/wiki/Black-body_radiation>
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[Question]
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For a SciFi project I work on I have a space-station orbiting earth that uses an 8 hour 3 shift system for its staff. Each shift is assigned to one-third of the countries and organizations on earth - namely those that are facing the station during the ~8 hours of the shift.
The above premise requires the station to be placed so that it will [stay relatively put](http://tvtropes.org/pmwiki/pmwiki.php/Main/WaitHere) in regard to the earth and one of her full rotations.
**Q**: Where can I put my station so it can observe a full rotation of earth?
[Answer]
From what I understand your requirements are thus:
1. The station uses a 24 hour time-keeping system split into 3 shifts, 8 hours each.
2. Each shift is staffed by members of the countries facing the station during that shift. Typically this amounts to 1/3 of Earth's organizations.
3. The station must orbit Earth in such a manner that it observes Earth's entire rotation. You expect that it must be stationary for this.
# Discussion:
## Lagrange Points.
In astronomy and orbital mechanics, Lagrange points are positions in an orbital configuration where an object remains fixed relative to the other bodies. Point 3 automatically removes typical orbital positions such as Low-Earth-Orbit and Geosynchronous-Earth-Orbits. This leaves the Lagrange points as a natural selection; but, there are 4 such points for Earth and The Moon and 4 more for Earth and The Sun.
## Earth-Moon Lagrange Points
If we look at the Earth-moon system, L1 is a natural point to choose for the station. It's situated between Earth and The Moon with relatively quick access to either body and can observe Earth's full rotation with ease. That being said, L1 poses 2 issues:
1. L1 is a unstable point. If the satellite drifts a bit, it can fall out of L1 and towards the Earth or Moon in an unstable elliptical orbit. Unfortunately this applies to all Lagrange points, but unequally. Depending on your SciFi scenario, this may not be an issue assuming the station has basic thrust capacity to keep it within the Lagrange point.
2. L1 is strongly coupled with the Moon's 27 day orbit. As a direct result, from the station's POV, in 24 hours it'll move 13.3 degrees around Earth while Earth would've rotated a full 360 degrees. As far the station is concerned though, it'll observe Earth rotate 360-13.3 degrees or 346 degrees. This means that if the prime meridian were directly below the station, after 24 station hours, the 13th longitude would be beneath it, and after 48 hours the 26th longitude, and so on... For comparison this would place Greenwich at 00:00, ~Naples, Italy at 24:00, Bucharest, Romania at 48:00 and Mecca, Saudi Arabia at 72:00. As you can tell, this would disrupt the proposed equal balance between shifts and world-powers. Unfortunately, this also applies to each other Lagrange point. **FURTHER DISCUSSION @ BOTTOM OF POST**
## Earth-Sun Lagrange Points
[](https://i.stack.imgur.com/Y6Bl3.png)
If we look at the Earth-Sun system, many of the same points for the Earth-Moon system still apply. The only major difference here is distance. For Earth-Moon, L1 is 326,390 km as measured from Earth to the Moon. For the Sun-Earth system, L1 is at 57,689,000 km as measured from Earth to the Sun. This would place the satellite well outside the Earth-Moon system.
### Sun-Earth L1
For the Sun-Earth L1 point, the 1st argument applies equally; but, the 2nd argument is nearly eliminated. The orbital period of the Earth-Sun Lagrange points is 1 year or 365.25 days. Therefore, during a single 24 hour station day, the station and earth will have moved about 1 degree around the orbit. This comes out to about 1 day for Earth. Technically, after about half a year, at 00:00 hours the other side of earth will be visible; but, now this is minimized dramatically.
### EM Radiation
Unfortunately, L1 for the Sun-Earth system experiences a lot of electromagnetic radiation.
# Answer: Sun-Earth L2.
If the station were placed at L2, it'd keep a close synchronicity with Earth's rotation without experiencing the EM radiation at L1. I will note that station would be 176x farther from Earth than at the Earth-Moon L2; but, whether or not this is an issue for your world is up to you.
# Errata:
Technically, I assumed Earth's orbit was perfectly circular. In fact this is not true; it's *slightly* eccentric. As a result, when Earth is closer to the sun during the northern winter months, it travels much faster therefore passing through more radial degrees per day and when Earth is farther from the sun during northern summer months, it travels slower. As a result, my calculations won't be exact; however, given the astronomical scales involved, the error range is small enough to qualify as a back-of-the-envelope calculation.
# Discussion on L1 Logistics
Here's a diagram I drew up:
[](https://i.stack.imgur.com/3ztKu.jpg)
Fundamentally, because L1 orbits with the moon, for every 24 hour period, points A,B,C,D will always return to the same position; but, the station will orbit 13 degrees to the marked L1 positions, each one above points A, B, C, and D respectively. Now suppose we have three shifts, each representing countries in the Cyan (CY), Magenta (MG), and Yellow (YW) nations below; and, suppose that the shifts are marked as CY from 00:00-08:00, MG from 08:00-16:00, and YW from 16:00-24:00. This means that after 9 days, the Earth will have rotated 9 times, and be at the same position; but, the station will have traveled 119.7 degrees around earth, or ~ 1/3 of its orbit. **As a result, when CY begins their shift at 00:00 hundred hours, they'll find that directly below them is the start of MG territory**. Normally this would indicate that they are ending their shift and MG's shift is about to begin; but, the station time is 00:00. **If you choose L1, your station will need to use a 23.11 H day with shifts every 7.7 Hours (7 hours 42 minutes) to ensure shifts start and terminate above their respective territories.**
[Answer]
Given the requirement to view the entire Earth once in a 24 hours period I can see only two solutions.
**You can either gain 15 degrees (1 hour) per hour on the rotation of the planet, or lose 15 degrees per hour.**
The former requires you to effectively (and exactly) "lap" the planet in a single day of its rotation, meaning you need to move precisely twice as fast. This puts you into a 12 hour orbit around the planet, meaning you make 2 orbits for the Earth's single rotation allowing you to see each point on the Earth by seeing 12 hours (180 degrees) of it on each orbit. Orbital distance [20,200km (approx)](https://en.wikipedia.org/wiki/Semi-synchronous_orbit). This allows the "near Earth" requirement and is the stable, safe option.
The latter forces you into a solar orbit as you have no effective movement relative to the Earth**1**. You can't just share an orbit though, you need to sit in one of the gravity neutral locations or you'll end up hitting the planet you're sharing orbit with. These safe locations are known as [Lagrange points](https://en.wikipedia.org/wiki/Lagrangian_point) and are numbered L1 through L5 based on location, seen in the image below outlined by gravitational contours.
[](https://i.stack.imgur.com/71gvo.png)
L3 is on the wrong side of the Sun so we'll write that off. L4 and L5 are 60 degrees ahead and behind the planet respectively and they are [stable](https://space.stackexchange.com/questions/215/are-lagrange-points-stable-over-a-long-period-of-time?rq=1) but put you too far away to be useful, they also have a downside in that they're often occupied by [trojans](https://en.wikipedia.org/wiki/Trojan_(astronomy)). L1, L2 are closer, but [unstable](https://space.stackexchange.com/questions/8667/is-lagrange-point-l1-stable?rq=1), L2 being more stable than L1. This breaks the "near Earth" requirement, but is apparently what you're looking for.
As a side note, NASA advises [L5](https://settlement.arc.nasa.gov/75SummerStudy/Chapt4.html#Where) for [long term habitation](https://settlement.arc.nasa.gov/75SummerStudy/Design.html)
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**1** This is a three body problem, the bodies being the Sun, the Earth, the space-station. The Sun is the datum used to define the relative movement of the other bodies, not the rotation of the Earth.
[Answer]
The title of the question, and the *actual* question, do not seem to match up.
If different countries are visible during different parts of the day, then the station *is not* remaining "put". If you want it to "stay put", you need a geostationary orbit, at an altitude of 35,786 km.
If, on the other hand, you don't want it to "stay put", but you want it to pass over the same part of the Earth at the same time every day, that's quite different. In particular, it looks like you want it to make one revolution with respect to the co-rotating frame of the ground once per day, so that it passes over each line of longitude once every 24 hours.
There are two ways to do that: you can approximate it by orbiting *really far away*- like, as far out as the moon, or farther, so that for all practical purposes the station is completely stationary, and the Earth turns beneath it. If you place it at any of the Earth-Sun Lagrange points, that will work out perfectly- but the closest of those (the L1 point, on a line between the Earth and the Sun) is about 1.5 million km away. Not terribly practical if you need to communicate with the ground in near real time, or if you need to see things clearly.
Probably the better solution is to use a 12-hour sun-synchronous, (aka [semi-synchronous](https://en.wikipedia.org/wiki/Semi-synchronous_orbit)) orbit. This way, after one orbit to the same position with respect to the sun (about 2 minutes longer than one sidereal orbit), the Earth will have spun half-way around, and you will have passed over 1/2 of the Earth along the way. And the second orbit, you will pass over the *other* half of the Earth. Your three shifts will thus be split up over 2 orbits.
The approximate altitude for such an orbit is 20,200 km.
[Answer]
Okay, according to [this site](http://www.physicsclassroom.com/class/circles/Lesson-4/Mathematics-of-Satellite-Motion), one of the formulas for calculating properties of a satellite's orbit is the following:
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> T^2/R^3 = (4\*pi^2)/G\*Mcen
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>
> T = orbital period in seconds
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> R = avg Radius in meters
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> G = gravitational constant
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> Mcen = mass of the body to be orbited around (in this case Earth)
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>
>
We know G and Mcen, and we want T to be such that from your point of view on Earth, it takes 24 hours to orbit. We could either orbit slower than Earth rotates, but we'd have to be so far away we're effectively stationary, which has been covered in other answers. The other option is to go faster than earth rotates (specifically twice as fast), thus we'd need to orbit twice in 24 hours which gives us an orbital period of 12 hours.
This is because orbit and space and what-not is all described from a point of view. It's why people thought the sun orbited the earth for a while, before we realised we orbited it and rotated to cause the same effect. From the Moon's point of view it stays still and the earth slowly spins in place in the sky. From Earth's point of view, your stations passes through the sky exactly once a day, at the same time. From some distant observer outside of the solar system the earth spins once every twenty four hours and your station orbits it once every 48. Movement in space is all about perspective.
Thus, inserting all the numbers: (12 hours equals)
43200^2/R^3 = (4\*pi^2)/(6.673 x 10-11\*5.972 × 10^24)
Multiply G and Mcen:
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> 43200^2/R^3 = (4\*pi^2)/3.9851156\*10^14
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>
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Multiply each side by GMcen and R^3:
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> 43200^2\*3.9851156\*10^14 = 4\*pi^2 \* R^3
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Multiply out the left side
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> 7.43718\*10^23 = 4\*pi^2 \* R^3
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>
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Divide both sides by 4\*pi^2
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> 1.88386\*10^22 = R^3
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>
>
cube root everything
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> 26608243.6243 = R
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>
>
We now have our average orbital radius of 26,608,243.6243 meters. This is from the center of the Earth though. Earth's radius is 6.371 million meters, so subtract that and we get an approximate altitude for your station of **20.2 thousand km**.
[Answer]
This is a kind of alternative to KareemElashmawy's answer.
As they point out, the best you can do with a single station is to put it in one of the Lagrange points, but these have problems.
The Earth/Sun L1 point is too far away from Earth, and has fairly high radiation.
The Earth/Sun L2 point has lower radiation, but is also far away, and you'll only ever see the night side of earth.
The Earth/Moon L1 point would be close enough, but you'd be tied to the Moon's day/night cycle, which is 28 days long, and so half the cycle you'd see the Earth's day side, and half the cycle you'd see the Earth's night side, which isn't ideal.
None of these points are stable, and so you'd have to constantly monitor your position and apply corrections to stay on station.
Unless you want to use magic level tech you can't have an orbit that stays solely between the Earth and Sun and is within the orbit of the moon. You would essentially have to constantly expend thrust in order to hover in that position.
So I'd like to propose a "PQ" solution; Have three space stations in geostationary orbit. Each station would stay active while the section of the globe that it's monitoring is in daylight. This has a side advantage that there would be no back side of the planet that one of the stations couldn't see which could be useful for emergency and traffic control purposes.
[Answer]
You want your station to observe one full rotation of the earth. I take that to mean that in one day, persons on the station see the entirety of earth pass beneath them.
A [geostationary orbit](https://en.wikipedia.org/wiki/Geostationary_orbit)
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> is a circular orbit 35,786 kilometres (22,236 mi) above the Earth's
> equator and following the direction of the Earth's rotation.
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>
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It helps me to see it. Here is my depiction, with the Earth as a clock face. The station orbits keeping 12 beneath it as the earth turns. To stay above 12 the station must orbit earth in 1 day.
[](https://i.stack.imgur.com/2LF16.jpg)
Now use that same 24 hour orbital path at 35786 km that the geostationary satellites use, but go [retrograde](https://en.wikipedia.org/wiki/Artificial_satellites_in_retrograde_orbit). These are dangerous orbits!
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> Nevertheless, a satellite in retrograde orbit could pose a major
> hazard to other satellites, especially if it was placed in the Clarke
> belt, where geostationary satellites orbit.
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>
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Now the satellite moves contrary to the rotation of the earth. At 12 hours the satellite will be again above its starting point, having seen ~~half~~ **the entirety** of the earth rotate beneath it. Then it sees the ~~other half~~ entire earth move past again and at 24 hours is again above its starting point.
This answers the question in that the station does see one rotation each day. And then another one, the same day. Question does not specify "one and only one" rotation seen per day.
[](https://i.stack.imgur.com/7aFia.jpg)
[Answer]
Ummm... okay so I think the only solution is to put it in a separate but Earth oriented orbit so either [L4 or L5](https://en.wikipedia.org/wiki/Lagrangian_point) in a [Trojan](https://en.wikipedia.org/wiki/Trojan_(astronomy)) orbit, or [L3](https://en.wikipedia.org/wiki/Lagrangian_point#L3) on the far side of the Sun. All these positions allow for uninterpreted observation of the Earth and a stable spacial relationship between the station and the Earth but none of them orbit the Earth. Any orbit of the Earth is going to have an offset period so the station won't be able to operate on an Earth matched clock, the station will go around the Earth in 12 hours while the world turns or some other none observation matched period. L1 and L2 also fit the bill in terms of orbital stability but they are not themselves stable because of Lunar gravity, they are much closer to the Earth though and the cost of propellant to maintain position in the lagrange zone might be worth it to reduce signal delays (light speed signals need 32 minutes for a round trip at L3, something on the order of 11 minutes for the Trojans, 10 seconds for L1 and L2).
Actually a 48 hour equatorial orbit (along the true rotational equator) that chased Earth's orbit should have a "lap time" of 24 hours, I think that fulfills your needs. So orbital radius approximately 67000km, velocity 2.5km/s, aligned with Earth's rotation, someone will probably point out why this doesn't *actually* work but it works in my head and appears to work on paper. The station goes around the Earth in 48 hours but it's overhead times will match up on a 24 hour cycle.
[Answer]
You mentioned this is a Sci-Fi project, so I'm going to approach this question more as a writer than an astrophysicist. The simplest way I could explain the mechanics would be to initially place the station above the international dateline. Then maintain a geosynchronous orbit opposite to the rotation of the Earth, but only so much so that in 12 hours, the international dateline (because the line circles the globe) will pass again under the station. In 24 hours, the station should return to where it initially was above the international date line.
[Answer]
A slightly different answer than the others seem to be.
Two potential locations for a station to orbit the Earth and be a near match for your requirements.
One is to build the station on the Moon on the side perpetually facing Earth.
The other is to set your space station in the same orbit as the Moon, but on the opposite side of the Earth. This will likely take some active station-keeping to maintain the orbit.
For both of these locations, I believe the time it will take for the station to again be directly over the same point on Earth is just under 25 hours (split into three 8 hour, 20 minute Shifts, which includes slight overlap).
This does mean that there will be a gradual shift of which Shift is responsible for which parts of the planet. However, if it is absolutely required that the same people cover the same sections of the planet, it would be fairly simple to set up shift schedules to move personnel from one Shift to another, to match up with their geography.
With redundant personnel in each Shift (required anyway for illness, time-off, vacations to Earth, and random alien abductions), it is absolutely trivial to schedule such a change.
[Answer]
It is not really clear what you exactly mean by "it will stay relatively put in regard to Earth" (I also failed to understand the linked reference).
* If you want the S.S. to be fixed with respect to Earth, so it will appear to be "suspended" in a fixed point, then you need a geosynchronous orbit. *Note* a circular geosynchronous will appear to be fixed, a nice variation is to have a highly eccentric geosynchronous orbit that will draw a vertical "figure eight" on earth spending *much* more time on one than the other; this is used to have a satellite to be "mostly" over USA & Canada while flying over Brazil for a much shorter period.
* If you want to stay fixed with respect of Earth-Sun axis, so it will appear to pass over a certain point always at the same time of day, then you need to put your station in a Lagrange position of Earth orbit; in that case your best bet is L1 (between Earth and Sun) that is the nearest to Earth, just a bit farther than Moon's orbit; *note*: L1 is an unstable position, so it needs to be actively kept with attitude engines or similar devices.
* A reasonable compromise would be to be "fixed" with respect to Earth-Moon system, in this case the L4/L5 positions are advised; You will have a small delay daily in S.S. position with respect to Earth-Sun system, but it will be nearer (same distance as the Moon) and in a *stable* orbit (no corrections needed).
Please clarify what alternative you need.
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[Question]
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With the help of my allmighty *Handwavium* I want to change the biology of a human being so that this particular human being gets his eyes replaced with the eyes of a martial eagle. According to [Wikipedia](https://en.wikipedia.org/wiki/Martial_eagle)
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> Martial eagles have been noted as remarkable for their extremely keen eyesight (3.0–3.6 times human acuity). Due to this power, they can spot potential prey from a very great distance, having been known to be able to spot prey from as far as 5 to 6 km (3.1 to 3.7 mi) away.
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The human in question gets this ability via handwaving. Just like in the last installments of my little series "How would it affect a human to suddenly..." "[... hear like a cat?](https://worldbuilding.stackexchange.com/questions/68882/how-would-it-affect-a-human-to-suddenly-hear-like-a-cat)" and "[... have a sense of smell comparable to a wolf?](https://worldbuilding.stackexchange.com/questions/90456/how-would-it-affect-a-human-to-suddenly-have-a-sense-of-smell-comparable-to-a-wo)" the process can be ignored and the individual is not directly affected by the change so that he can continue with his normal life. Other people won't directly realize that this individual has the eyes of a martial eagle instead of his own.
The setting is Europe and we will imagine this human to be a middle-class white-collar worker. If an average human would, from one day to the other, be able to suddenly have a far better visual sense than other humans - what would be the biggest problems this human would have to face in his everyday life?
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**There will be several effect and acuity is the least of them.**
**Color** will be a bigger effect than acuity, birds see more base colors than we do. Many things will suddenly be the wrong color, especially blues, blacks, and purples (to us). Additionally there will be several completely new colors we don't even have words for since they can see into the ultraviolet.
Diurnal birds also have worse night vision than humans (fewer rods), so your guy will likely experience **night blindness**.
Birds have something called a [Pecten oculi](https://en.wikipedia.org/wiki/Pecten_oculi) which supplies nutrients to the eye and will mean they have a **bigger blind spot**, this will not have much effect unless they are close to something and looking up at the same time however. Oddly this may also be allow birds to [**detect magnetic fields**](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1976598/), how this would translate to vision is anyone's guess.
Visual acuity will not have much effect. The amount of the brain devoted to processing visual information is not any larger and with the increase in incoming information (new color and magnetics) it has to process your human may actually experience a lose in acuity, not a gain.
[](https://i.stack.imgur.com/49two.jpg)
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Let me answer this from personal experience.
While I am not eagle-eyed, I had been blessed with a vision that's better than most people have (and my brother's vision is even better than mine).
First of all, good vision does not provide any "superpower" equivalent. An average human equipped with a pair of binoculars or magnifying glass would always be better than an "eagle-eyed" human. Such a human, however, would have an edge among peers in sports, particularly in shooting. While I never particularly excelled in shooting, I never doubted that I had an aptitude for it, and, should I choose to practice, I might have achieved some success. An eagle-eyed human can potentially become a champion shooter. However, eyesight is not the everything in this sport.
Good eyesight provides convenience for everyday life - you don't have to come close to be able to read a posted note, you don't have to get the best tickets to enjoy the show, if you accidentally drop something small, you don't have to get on your knees to find it.
Also, you can exploit other's expectation of privacy. You can see what other people writing or typing when they assume you are too far away to be able to see anything. An eagle-eyed human can make a criminal or spying career by stealing passwords and other important information.
There are some things that can be called inconveniences. For example, I've been always too much distracted by the black grid of plasma TVs. Gray grid of an LCD is much more pleasant to an eye. Also, I've always been too keen to spot foreign objects and insects in mine or someone else's food. One or two incidents may be exciting, but after a while you'd get a dubious reputation among your friends and start wondering whether it's better to keep quiet.
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The biggest problem with increased visual accuracy would be that images of things which are essentially made of dots (photographs, printer output, computer displays), would look like they are made of dots and this could be annoying. Think of reading stuff from a old dot matrix printer or and old low resolution computer display.
I am assuming you don't have a processing problem because the handwavery takes care of that the human still only has a human visual arc because the eyes are redesigned to be in the front of the head as opposed to the side as with a eagle. Both these could be problems if not corrected for.
Note also eagles can distinguish more colors which is not the same think as visual acuity.(thing the opposite of colorblindness eg "I know everyone tell you that scarf matches those pants but they don't")
please excuse my spelling disability
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Keep in mind that an eagle has unique eyesight, fine tuned for its particular living conditions.
Eagles have a high density of photoreceptors at the center of their retina. This gives them a magnified spot in the center of their vision, but good wide angle view as well around the periphery of their overall vision.
That is optimized for aerial hunting - wide angle to look for movement, with a magnified spot in the middle to fully identify the moving subject.
Actually carrying out an attack can be dangerous to the hunter, there is the possibility that the hunter can become injured (which to a bird of prey is pretty much a death sentence) if they attack an animal that can fight back, like a big cat, or canine. Or that magnified view might also reveal a ground based predator nearby that could take down the eagle as it attacks its prey.
So the ability to fully identify the target and any ground based predators nearby before committing to an attack is a big bonus.
Now, how does that benefit a human? Might be of benefit to a soldier that can attack from a distance, say an expert archer. Otherwise, that magnification spot in the middle of their field of view probably wouldn't do the average human a lot of good. Humans, being capable of building and using tools, can always carry binoculars.
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The answer: distraction. The “new” sources of visual data would overwhelm the individual at first as their brain struggles to process and make sense of this sudden change. Some familiar objects will become unfamiliar as details long ignored reveal themselves, maybe for the first time. All of this would go far in disturbing their equilibrium perhaps for weeks after that. But thanks to a documented brain phenomenon called plasticity, he or she would eventually adapt and carry on with his or her life. Perhaps new career pathways, hitherto inaccessible to this person, will then open to them… or not. Of course, this outcome assumes that the individual is resilient and can come to accept such a drastic change in perspective. If that isn’t the case, then they’re screwed. Some people never adapt for one reason or another.
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In my story there has been an event which made the air toxic. Just a few breaths guarantees death.
What event could create such an atmosphere in an unfixable way?
The time is just before WW1. I was thinking some sort of large scale government experiments going wrong, but not sure what.
An idea I had was chlorine gas, but i'm not sure if that would be permanent.
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In general, nothing.
As I mentioned the previous few times [a question like this has come up](https://worldbuilding.stackexchange.com/questions/2492/could-normal-human-development-lead-to-a-sufficient-air-pollution-to-make-gas/2493#2493), toxic gasses are toxic because they react readily. This means they tend to break down on short timescales: sulfur dioxide, for example, has an atmospheric half-life of around 24 hours, and even long-lived stuff like nitrogen oxides don't last more than a month or two.
In order to get a permanently poisonous atmosphere, you need to release so much of your chosen poison that everything it can react with, it has reacted with. This happened once in Earth's history: the [Great Oxygenation Event](https://en.wikipedia.org/wiki/Great_Oxygenation_Event), and took somewhere between 2000 and several hundred million years. For more exotic poisons such as chlorine, there may not be enough of it in the entire world to do the job.
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This idea is the topic of Arthur Conan Doyle's novel [The Poison Belt](https://en.wikipedia.org/wiki/The_Poison_Belt).
In this story, the poisoning is caused by the passage of the Earth through a poisonous volume of the [luminiferous aether](https://en.wikipedia.org/wiki/Luminiferous_aether). Sadly, this is probably no longer an option for you, since the aether has been shown not to exist.
Alternative options might be the earth passing through a dense cloud of [interstellar hydrogen cyanide](https://en.wikipedia.org/wiki/List_of_interstellar_and_circumstellar_molecules#cite_note-Ziurys06-32), or fast growing bacteria producing toxic gas as in the [Great Oxygenation Event](https://en.wikipedia.org/wiki/Great_Oxygenation_Event).
Another example from literature is in [Zodiac](https://en.wikipedia.org/wiki/Zodiac_(novel))
by Neal Stephenson, in which a genetically engineered bacteria which has the potential to liberate all the chlorine held in the world's saltwater oceans is released into the wild.
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Nanotechnology.
Quasi-living self reproducing machines the size of cells. They are essentially a synthetic fungi meant to produce enzymes to mine old landfills and trash.
By mutation or accident they produce a disassembler sub-unit that becomes airborn. It happens to be extremely toxic, as it affects some critical system in the body.
The pseudo-fungi have escaped and gotten into the soil and is spreading all over the world. Everywhere you have compost or topsoil or garbage, it grows and releases this deadly gas as a side effect.
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Let's get some rough numbers on this. Earth's atmosphere has a mass of about 5x10^18 kg. HCN seems like a good example of a gas that's deadly in low concentrations: the recommended upper limit for exposure in air is 4.7 parts per million, and the immediate danger level is 50ppm. The kind of rapid death you're looking for will happen at a higher level, let's say 100ppm, which is 1/10,000. So we need about 5x10^14 kg of HCN. That's really quite a lot.
The interstellar medium is really low-density. About 10^-13 times the density of Earth's atmosphere, but let's give it 100 times that for a freak cloud, 10^-11 of an atmosphere, and 10^-4 of an atmosphere of HCN is deadly. So the Earth needs to sweep up 10^7 times the atmosphere's volume of this molecular cloud. That would actually be possible in a few months in that cloud, since the Earth moves a distance equal to about 3.5 times the equivalent depth of the atmosphere every second.
The (fortunate) reason this won't actually work is the solar wind, which maintains a [bubble](https://en.wikipedia.org/wiki/Heliosphere) of reasonably friendly conditions around the solar system. If the system moved into a dense molecular cloud, the bubble would shrink, but I'm reasonably sure the Earth would still be inside it and not exposed to the molecular cloud. It currently extends far beyond Pluto's orbit, call it a 50AU radius spheroid. If it shrinks to 5AU radius, it gets a thousand times denser, well above the density of the cloud.
A comet made of semi-pure HCN hitting the Earth could provide enough. We need about 7.5x10^8 cubic metres of frozen HCN (density about 0.7 tons per cubic metre) which is about a 2km comet. That doesn't cause a mass extinction just as an impactor, but the HCN would. It's fortunate comets don't come in high-purity grades.
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How real do you want this?
Real enough that it could actually happen (why? — are you hoping to do it?)
or just real enough to be plausible in a work of fiction?
As you probably know, diamonds and graphite (pencil “lead”)
are both pure [carbon](https://en.wikipedia.org/wiki/Carbon).
They are distinguished by different crystal structures.
They are called [allotropes](https://en.wikipedia.org/wiki/Allotropes_of_carbon), and there are others.
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> **Warning:** spoilers ahead.
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[Polymorphs](https://en.wikipedia.org/wiki/Polymorphism_(materials_science)) are similar to allotropes,
but the term *allotrope* applies only to elements,
while *polymorph* applies only to compounds.
Polymorphs are most often found in minerals and organic compounds
(e.g., pharmaceuticals).
There are polymorphs of ice (solid $\mathrm{H\_2O}$),
but the ordinary ice that forms on puddles in winter
(and that we make in our freezers and put into our drinks)
is the only one that can exist at standard pressure.
However, Kurt Vonnegut’s novel [*Cat’s Cradle*](https://en.wikipedia.org/wiki/Cat%27s_Cradle) stipulates
that there are others that can exist at standard pressure.
In particular, one called [“ice-nine”](https://en.wikipedia.org/wiki/Ice-nine)
has a melting point of $\mathrm{45.8\:°C}$ $(\mathrm{114.4\:°F})$,
so it is stable at room temperature — and, indeed, on most of the Earth.
It has the additional property
that if any liquid (or gaseous) $\mathrm{H\_2O}$
comes into contact with ice-nine,
it immediately freezes and also becomes ice-nine.
For most of the book,
the ice-nine is kept carefully controlled and locked away.
But eventually it escapes into the environment
and causes all the oceans to freeze,
and it’s pretty much curtains for mankind.
[Oxygen has allotropes](https://en.wikipedia.org/wiki/Allotropes_of_oxygen), too.
The best known ones are ordinary, atmospheric oxygen $(\mathrm{O\_2})$
and ozone $(\mathrm{O\_3})$,
but there are others, including [tetraoxygen $(\mathrm{O\_4})$](https://en.wikipedia.org/wiki/Tetraoxygen),
which is unstable (or [metastable](https://en.wikipedia.org/wiki/Metastability)).
Wikipedia notes:
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> Triatomic oxygen (Ozone, O3),
> is a very reactive allotrope of oxygen
> that is destructive to materials like rubber and fabrics
> and is also damaging to lung tissue.
> Traces of it can be detected as a sharp, chlorine-like smell,
> coming from electric motors, …
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Now suppose that $\mathrm{O\_5}$ is stable
at standard atmospheric pressure and temperature.
And suppose that, like ice-nine, it acts as a catalyst,
converting $\mathrm{O\_2}$ (and maybe also $\mathrm{O\_3}$) into $\mathrm{O\_5}$,
and that this conversion is very hard to undo (think particle accelerator).
It would be quite reasonable to expect $\mathrm{O\_5}$
not to react chemically the way $\mathrm{O\_2}$ does
(remember the differences
between the characteristics of diamonds and graphite).
Once this stuff got into the lungs of an oxygen breather,
it would convert all the ordinary oxygen
(including, eventually, the stuff in hemoglobin) into $\mathrm{O\_5}$,
which would not give the cells what they need.
You’d suffocate.
Or maybe it’s just very, *very* bad for you — like ozone.
I don’t know how $\mathrm{O\_5}$ would be created with pre-WWI technology,
but the existence of tetraoxygen $(\mathrm{O\_4})$
was first predicted in 1924 as a result of experiments with liquid oxygen —
so that technology existed then.
You would need very little handwavium to explain how somebody cooled oxygen,
past the point where it condenses into a liquid,
near to its freezing temperature,
and this caused $\mathrm{O\_5}$ crystals to form.
When allowed to thaw, they did not decompose,
but rather started a *Cat’s Cradle*-like chain reaction
that converted all the oxygen on the planet into toxic $\mathrm{O\_5}$.
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Global warming causes the oceans to become anoxic, leading to the production of large amounts of hydrogen sulfide. Theorized to have happened during the Permian-Triassic extinction. See e.g. <http://geology.gsapubs.org/content/33/5/397.abstract> Not of course universally fatal, at least the P-T version, because some species did survive.
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Do not add anything, just remove oxygen. If the partial concentration of oxygen in the air drops our lungs will be unable to maintain oxygen in the blood. Indeed stepping out to low-oxygen atmosphere will result in the oxygen in our blood being rapidly lost. The effects will be the same as if the air was toxic despite the process actually working in the reverse.
Losing the oxygen itself is fairly simple, just burn something and free oxygen will be consumed. The only issue is that it can't be carbon since photosynthetic bacteria can reduce carbon dioxide, that is why we have free oxygen in the first place.
The two valid alternatives are hydrogen and iron. The two valid sources for either are from space or from terrestrial deposits. The choice matters in ways that are beyond this question as all alternatives have huge "side effects." I am **not** going to explain those in detail here. I mean, the question **is** old and it **is** better to ask for details in a follow up question.
For hydrogen the alternatives are a coronal mass ejection or a series of them releasing huge amounts of hydrogen which then hits Earth and huge amounts of methane or hydrogen sulphide being released by volcanism. Or just global warming.
For iron, metallic meteorites could bring it to Earth. If the individual meteorites are small enough they'll burn in the atmosphere are bind oxygen. The metal dust or rabble could be left overs from solar system formation or a result of **successfully** stopping an extinction level asteroid hit. Volcanism could release huge amounts of iron if everything goes "right". The iron is down there, it is just unlikely for something to bring it up.
Such deep volcanism might also bring up lots of other things that burn and bind oxygen. Silicon and aluminium for example are fairly common and bind oxygen into silicates or aluminosilicates (aka rocks) that life cannot release oxygen from.
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So, I'm trying to come up with my own world system where words like(for example): Magic, Alchemy, Sorcery, etc and have a specific meaning. Also being a(n)(for example): Alchemist, Witch, Sorcerer, Gypsy, Pagan, etc are all different things. I'm running the problem that I feel that one thing is not that much different from the other. That they're not that distinct or that they're too alike. Any help or tips that I can make them distinctly different?
For example, magic in my world runs like batteries. A wand or amulet or staff is infused with a magic-source item and when this item runs out of magic, the magic-user resorts to his life-force. They can obtain more wands and the like, though. Of course, they're expensive, especially if a item has more magic energy than the other. Moving on. Sorcerers are people whose magic is genetic. A Witch/warlock is a human who learned the art. But what makes one special from the other? I know I'm supposed to be the one to make the differentiations but I'm stumbling over myself here. A demonesque is someone who hexes other people and "hijacks" their life force for their own magic use. They sell their services to people to make money, usually. "Pay me for a location spell," and the like.
Another example of my troubles. For example, a sorcerer casts an invisibility spell over himself. Can't a witch/warlock do that same? Then why are they different at all? Why not sum them up to a different class? Mystics, for example.
Perhaps I'm just looking for variety and lines drawn plainly. I would explain my whole logic and world if not for the fact that it's "under construction."
It bothers me (this for example): Let's say we have a person with shapeshifting abilities, which is rare. But we also have a witch that has cast a spell or has an amulet that allows her to do the same thing. Why would the Shapeshifter be so rare if you can achieve the same result with magic?
I don't know if I'm explaining myself right here if at all, but any answers or suggestions or even explanations would be great. At this point, I feel like I'm being extremely anal.
I'm trying to put everything in layman terms without launching into three pages of dialogue or writing on "how race is different" or "why and how this works."
Simplicity is the best.
Thanks.
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It sounds to me like there are two concepts at play in your magic system.
1. How each type of magic works.
2. What each type of magic can do.
For example, you've defined a difference between Sorcerers and Witches:
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This is a difference in (1). How does the magic work (where does the power come from?) However, it is *not* a difference in (2). You haven't indicated any difference in what the two can *do.* Witches can fly, and so can Sorcerers.
Your problem is that you've introduced a lot of types of magic that are extremely similar to each other, but you want them to all be totally unique.
To solve this problem, you'll need to provide strict limits to what each type of magic can do. A common trope is the four elements. For example, In Avatar: The Last Airbender, Benders can manipulate air, or water, or earth, or fire, but *not* more than one. The powers of each type of Bender are clearly delineated.
Or consider Sanderson's *Mistborn* series. In that series, one type of "allomancer" can temporarily improve his physical strength. Another can enhance his senses. Another can dampen others' emotions. And so on. Each type of "caster" has very specific abilities that the other casters do not have.
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I think one entity with magic can be combine with different characteristic:
1. Source of the Magic
2. Type of the Magic
3. Race
**For the source of the Magic**: we can categorize it with: Sorcerer and Wizard have the source in there gene, Witch use magical charm or wand, Alchemist use ingredient to make potions and hex bags..
**For the type of magic**: I suggest using the "Might & Magic" series system. With Elemental magic like Fire, Water, Earth, Wind and Spiritual Magic and Mind Magic like Heal, Hypnotize, or Fear..
**Race**: This will explain the skill like Shapeshifting, bloodsucking. The skill goes with the race of the entity.
A combination of those three will make up the magic-using entity in your world. Like
- A Shapeshifting Alchemist which specialize in Fire Potions that can make fire balls or fire wall and can use the Skill Shapeshifting
* A Vampiric demonesque can sell various spell if their expertise is broad enough. Like a wand of mind control, or a hex bag of craziness.
* A Human Wind Sorcerer or Wizard can cast thunder bolt out of their hand, but have no special skill.
Thanks to [celtschk](https://worldbuilding.stackexchange.com/users/98/celtschk) answer we can distinguish between magic and skill. The skill is used with the cost of anything other than magic. So even if they are not sorcerer, but they have the skill they can do it without magic aided item.
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It sounds to me like each of your different magic types draws their power from a different source. Sorcerers get it from themselves, demonesques get it from other people, and maybe witches/wizards get it from the environment, or from wands/amulets.
An analogue to this could be found in light sources. Say you have a light connected to a wall socket, a light connected to a battery, and a light with a hand crank charger. Even if these devices have the same output, they're going to look very different, and be useful in different situations. Some differences:
1- Hand crank takes a while to start shining, you don't want it for quick illumination, but it's useful anywhere, forever.
2- Plugged in light isn't very mobile, you don't want it if you're travelling or don't have access to a socket, but it has a lot of power at its disposal once it's plugged in.
3- Battery light is useful on the move, but it can run out and need recharging.
So, at least in terms of speed, availability of energy, and portability, I'd think your magic types would have enough differences to distinguish themselves. If you want more differences than this, try thinking of other tasks that can be accomplished in different ways, and try mapping your types to those.
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As some others have noted, the primary distinction between the magics depends both on what their practitioners are capable of, and what the source of a practitioner's ability is. I would say that there are other factors, though, namely: What *must* be true of each caster? In other words, does the magic do anything to them? Also, what is the general life philosophy of people who practice a certain kind of magic? This is really important for plot purposes, since the restrictions people create are often more important than those nature imposes.
For example, you state that pure shapeshifting magic is rare, but question why that would be if a witch can simply do the same thing. Well, calculators are ubiquitous, but a person who can multiply 10-digit numbers in their head, in less than a second no less, is still quite a savant (not an Allomantic savant, Benjamin). So perhaps the witch has to go through a lot of effort to shapeshift, whereas an innate shapeshifter can do it in the blink of an eye. Or perhaps certain spells require much more power than others, and a witch who can shapeshift is very powerful indeed, so that there are actually more shapeshifters than witches who can change their shape.
As for witches and sorcerers apparently having the same powers, this is really not a problem at all. The situation you have is basically identical to that in D&D (at least v3.5), where wizards and sorcerers essentially differ only in source of their spells (learning or magical ancestry, respectively). Thinking about this from a social perspective makes a lot of sense. In your world, a sorcerer may be born with the ability to perform powerful magic. But if I am not a sorcerer, maybe I still want to learn. Maybe there are not enough sorcerers to get everything done. And here you get into the non-magical characteristics of each group. Witches are smarter. They can read at a college level, they know the theory of magic. They won't kill themselves trying to stop the tide or do something similarly ridiculous. Maybe they look down on sorcerers, who always seem to be setting their villages on fire.
Now, of course you can "sum" the two classes and call them mystics. The people in your world probably do exactly that, to distinguish them from demonesques and so forth. However, just as a painter is not the same as a sculptor, even though they are both artists, so too are there distinctions among various mystics.
P.S. As a side note, using the terms *gypsy* and *pagan* to refer to certain classes of magic-user might be problematic when it comes time to publish (if that is your plan), insofar as they refer to real-life groups that are still extant, and the first one is often considered pejorative. Perhaps *traveler* or *wanderer* might work for the former, and *druid* or *shaman* for the latter.
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Perhaps you could take some inspiration from the similarities between Chemistry, Physics. Each field takes a different approach to a problems and solve different sets of problems though the three fields are tightly bound together by a heavy dependence on Math.
The below comic may also offer you some insight into how to order the various practitioners of magic in your world. They will all be "magicians" but some more pure magic users than others.
[](https://i.stack.imgur.com/1zIB2.png)
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Someone else mentioned D&D. Expanding on that:
Clerics have a really large pool of spells to choose from but can only have a certain amount known at a time and these are divinely given knowledge. They really have no idea how they work, other than they do.
Sorcerers are the innate, powerful type that have inherent talent but a fairly limited pool of spells.
Wizards are the scholar-type magic user - they have to spend time each night to memorize the spells they want to use the next day. They have a wide array of magic (though not as much as the cleric) and can cast some powerful spells but tire quickly.
Perhaps you can make distinctions in the effort it takes to learn/cast the spells that is tied in to the source of the magic. For instance, a genetic-ability person could cast some instinctively but have a hard time learning and casting more than that. A cleric type may be at the mercy of their deity and randomly forget some spells overnight - education and training for them may involve learning how to recognize what they have available each day or learning to actually *learn* the spells once they have them so they can still cast them after they would otherwise forget albeit at a less powerful level. A wizard would simply need to be in school for EVER and take a while to learn new things - in this sense wizards would typically focus on one or two specialty spells and market themselves as masters of certain useful things.
Healers may get their powers from nature (perhaps they are human-dryad half-breeds) and need to be in contact with some form of flora or fauna to actually cast a healing spell.
I like what you did with the Hexer class - using life-force is a good way to make a distinction and at the same time give them a limit.
Also, I love what Jonah said (and don't know how to properly quote him):
" [Witches] won't kill themselves trying to stop the tide or do something similarly ridiculous. Maybe they look down on sorcerers, who always seem to be setting their villages on fire."
I play D&D with a sorcerer who randomly farts out bursts of uncontrolled magic... It makes things really interesting when he is trying to kill a zombie and instead casts levitate on the skeleton archer.
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I had to dig this up from an answer I gave a few months time ago: [Will my magic system decrease its credibility?](https://worldbuilding.stackexchange.com/questions/13339/will-my-magic-system-decrease-its-credibility/13357#13357)
It is reproduced here for convenience. The verbiage is slightly different (this particular question was looking at the credibility of their magic system), but the situation is very similar. They were worried that having multiple ways to do the same magic would hurt their credibility. You appear worried that your multiple magics aren't different enough. I believe the same terminology-and-approach argument works in both cases.
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I think you can maintain credibility with your magic system. I would feel comfortable claiming we have similar verbiage in real life describing martial arts. All of the martial arts are going towards the same goal, but the paths they take are strikingly different. Given that I can see real life corollaries, credibility should be possible.
If you wish to use this martial arts metaphor to maintain credibility, I recommend carefully crafting the way people view the world to match their particular magic style. If someone has "witch" style magic, they should view "holy" magic in witch-magic terminology, trying to explain how holy mages do their things in terms of the trinkets and familiars and spells witches use. A holy mage will describe the same abilities using different verbage. A natural magic worker might view holy magic as a very strict version of growth without much room for self expression.
Each style should be able to do anything, but there may be things which are hard to do using one style, and easy to do in another. If it is hard to do in a style, individuals who practice that style should develop lifestyles where they don't have any want to do things that are hard in their magic and easy in others.
As an example, Xing Yi, a Chinese martial art, focuses heavily on how to attack on straight lines. One would be foolish to believe they can't attack on curves -- such a mistake would be rectified shortly. However, their techniques function better on straight lines. They prefer it. Accordingly, they will structure their life such that many of the obstacles they want to overcome appear on straight lines.
In contract, Baugua, another Chinese martial art, focuses heavily on how to move in circular motion. Think they can't move in straight lines for a moment, and you'll regret it. However, their technique functions better on circles. They prefer it. Accordingly, they will structure their life such that many obstacles can be dealt with by rotating around them to find a better angle to attack.
If you ask a practitioner of Xing Yi about Bauga, they might say "sure, circles are nice, but if I can get ahead of your movement ever so slightly, I'll strike out in a straight line, and pulverize you. Circles are useless in comparison to straight lines. A practitioner of Baugua, when asked about Xing Yi, might say, "Yeah, they can put a lot of power on straight lines, but I'm not going to let anybody keep me on a straight line. I'll weave around, and when they weaken themselves by attacking and missing, then I'll strike them along a curve they can't predict."
Both styles are known as "internal" martial arts, and it is a commonly accepted attitude that they are "climbing the same mountain, just taking different routes." In fact, there's a third traditional internal martial art, Tai Chi, which takes even a different route. All of them go towards making the internal self better, but they do it in different ways. They each have different verbiages to describe the others, and practitioners will organize their life based on the strengths and weaknesses of their art.
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IIRC Sergei Lukyanenko's *Night Watch* series use a similar idea. there is a definite "hierarchy" of magic. Some are born into it, being magical creatures like Shapeshifters or Vampires. Some learn it, like magicians, and can only really "channel" magic via articles like Wands etc. Some can channel magic into items themselves for use later, or for others to use, whilst still others have a natural affinity for magic and can "just do" magic.
Sounds like you want to go with something similar -
* Alchemist - creates magical items for later use following specific rules (Magic rings, staffs, cloaks, wands)
* Witch - can use magical items to channel their magic more effectively
* Sorcerer - doesn't need articles to channel, can "just do" magic
* Gypsy - uses words (Spells) to channel their magic, as well as creating their own magical articles more naturally than the alchemist (potions and other natural stuff)
* Pagan - uses ritual to channel their magic
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You have to give your magic more rules. For example, is life force replenished over time? Does everybody have the same amount of life force? How do people use magic, is it used though incantation or is it more mental and possibly an action that activates it?
Once these and other questions like it are answered, you can apply the knowledge to different classes; like so:
* Sorcerers are people who have more Life force than a regular person, they could also have a magic power that they dont have to use an incantation for. They obviously also have the knowledge that has been passed down that family.
* Witches/Wizards can only use incatation and have the usual amount of life force.
* Shapeshifter are people who can use a type of magic without incantation but have no or little knowledge or skill of any other magic.
[Answer]
Well, let's look at the example of shape shifting.
A natural born shapeshifter will change form just as he wants. It will cost him only little effort, and because it's an ability he's born with, almost nobody else can do anything to prevent him from shape shifting. Nobody except demonesques, that is: Demonesques can stop naturally born shapeshifters by simply stealing their energy they need to shapeshift.
W witch can shape shift if she learned the spell, and manages to cast it correctly. If she didn't learn the spell, fails to remember it correctly, or fails to spell it correctly, she will not change her form, or worse, will change it in a different way than intended. You can stop her by preventing that she casts the spell; in the simplest case by simply holding a hand over her mouth (or some magic doing the same — note that we again have two ways to achieve the same result, physical and magical!). You could try to distract her while she casts that spell, so she fails to cast it correctly. Probably the spell is very complicated, so it's not easy to cast it correctly. Just like few people are natural born shape shifters, few witches master the art of casting the spell correctly. Moreover, unlike natural shapeshifters, witches cannot just change their own form, but use the spell on other people. A shapeshifter can turn himself into a frog, but not you. But a witch could just as well turn you into a frog.
A demonesque is dependent on other people whose power he can draw. If he can't draw from other people (be it because nobody is there, be it because their life energy is protected by some magic) he's powerless. Presumably to shape shift needs a lot of energy, so unless there are many people there whose energy he can draw (most people don't have enough energy to shapeshift, that's why there are so few naturally born shapeshifters), he won't be able to change form. In the worst case (for him), he's trapped in an unfortunate form because after changing form, some people left (or died because he drew too much energy from them), and he cannot shift back. The jackpot for him is if he can draw energy from a shapeshifter, because a shapeshifter has, of course, sufficient energy to shapeshift; while a demonesque draws that energy from him, the shapeshifter cannot shapeshift, however. Like a witch, a demonesque can shapeshift other people if he has the energy, however not those people he's currently drawing energy from.
Shape shiftzing may also be done by magig rings, produced by experienced alchemists. Creating a ring of shapeshifting is hard and takes lots of time; only the best alchemists can do it, and those rings are expensive and rare. On the positive side, everyone with only basic knowledge on using those rings can use them — provided they are currently in a shape that has fingers on which the ring fits. There is a well-known story about a man who stole a ring of shapeshifting and turned himself into a fly in order to spy on someone, but only after he was a fly he recognized that a fly cannot use a ring, and therefore he could not change back, and since flies don't live long, he died the next day (it is known because when you die, you always turn back into your original form, and it was observed how the fly turned back into the man). A ring of shapeshifting cannot be used to shapeshift anyone else but the wearer.
So you see, although all those different types of magic lead to shape shifting, they still have important differences. Only a demonesque can stop a natural born shapeshifter from shapeshifting. Only witches and demonesques can change the shape of other people. Rings can only be used if you're in the right shape.
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[Question]
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Is it actually possible in a 19th century setting to build horse-propelled, non-steampunk tanks?
This would mean armoured carriages with gatling guns and artillery on them, with several people sitting inside.
Also, how would could the horses and the person steering the carriage be protected?
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It's not only possible, it has actually been done in the Middle Ages. Check out [the Wikipedia page on the Hussite War Wagon](https://en.wikipedia.org/wiki/War_wagon), essentially an armored cart with heavy weapons (cannons, guns, or crossbows) inside. It contains additional information on how these were used, if you need to go more in-depth.
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Horse-pulled artillery [actually did exist](http://en.wikipedia.org/wiki/Horse_artillery) in the 19th century and earlier. However, as the emphasis was on mobility, they usually were lightly armored or unarmored.
From what I can tell, vehichle armor in the 19th century consisted of several inches of iron plate, backed by wood, and was used on ships and trains. The weight of such armor would be prohibitive for use with horses. However, this armor was made to withstand cannon fire. If you only needed to stop bullets or musket balls, you could do with a lot thinner armor, that might be more practical. Of course, if they're vulnerable to cannon fire, they wouldn't be especially useful as battle tanks. However, there are other roles for armored vehicles that might have a horse-drawn alternative.
Your best bet for function is something similar to an [infantry tank](http://en.wikipedia.org/wiki/Infantry_tank), which is a relatively slow-moving tank designed to support infantry attacks. For this, you wouldn't want artillery on your carriages, since you'll be too close to the enemy for that to be of much use. You could still have small cannons, like [swivel guns](http://en.wikipedia.org/wiki/Swivel_gun), that are lighter and designed as anti-personnel weapons. Also, breech-loading versions existed at that point, meaning soldiers don't have to get out of the carriage to reload them, which is a plus.
Armoring the horses themselves is impractical, at least if you do it directly. However, you could have them carry a sort of armored wall, like a [mantlet](http://en.wikipedia.org/wiki/Mantlet), around with them. The design of this is a bit tricky, since it needs to be flexible or segmented to get over rough terrain, but you don't want gaps in the armor. Just having some overlap between segments should be enough. You will also want them to be able to turn easily, to be able to bring the guns to bear once in range.
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The real question is whether this sort of vehicle or structure would be worthwhile. Anti-cannon armor is too heavy for horses, but a lightly armored version is still a fairly large and slow-moving target. Enemy artillery would be a serious threat. Still, if the vehicle stayed in motion firing broadside, it could be useful.
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Having looked at it from an engineering point of view, I will just add something from a horsemanship point of view: Horses are animals that live and survive through movement. They are uncomfortable being enclosed- to the point that some horses do not tolerate being stabled particularly well- even the equipment required for regular carriage driving is relatively hazardous ( and wrecks involving it tend to be very dangerous for humans and horses ) and sudden loud noises and strong odours tend to scare them, making them more inclined to try and run to safety.
Placing an animal of this type into a small box in the middle of a war zone and expecting it to behave like a mechanical engine is both cruel and exceedingly unlikely to offer you any practical benefit. You are more likely to have an armoured box full of panicked horses desperate to escape at any cost. This is probably one of the reasons that the tank required a mechanical engine before it's invention. From what I can tell of the armoured wagons mentioned in other answers, their purpose was more that of a mobile fortification- they probably would have been used to create a defensive structure quickly rather than as a mobile weapon.
You also have to consider the weight of armour, which would need to be supported by wheels ( the advantage of driving horses is that they carry no weight, only offer forward motion ) so you start to run into trouble the moment you get into muddy or wet terrain where your horses are stuck in a box that can no longer be moved. Or you go down a hill and start to accelerate under gravity. Or you go up a hill and can barely move due to the weight.
Putting it all together I fear this adds up to a somewhat impractical invention, but also consider why the tank arose at all: Even until 1914 cavalry were still a practical force on the battlefield, able to traverse ground rapidly and deliver fast and intimidating assault, although by the turn of the twentieth century they were more strategically deployed as a way of getting light dragoons into place fast. The inventions that limited that effectiveness were the machine gun and barbed wire, along with the standing front-lines of trench warfare. If you don't have those, then the necessity that lead to the invention of the tank is somewhat mitigated.
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Before machine gun, you do not need tank, because plain cavalry was more mobile, can pass over obstacles easier (horses do not have enough "horse power" to move armor around).
After machine gun, but before combustion engine (reliable and powerful enough to move tank), you have cavalry with [machine-gun chariots](https://en.wikipedia.org/wiki/Tachanka).
And once you have combustion, it is over for cavalry.
In war, it is not only about firepower and armor (protection against firepower). Mobility (and reliability) is also extremely important.
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It would really depend what you have in mind when you think of a tank.
A quick internet search brings up a number of examples of armored horse drawn carriages which would have been used in the 19th century.
The 1967 film [The War Wagon](http://en.wikipedia.org/wiki/The_War_Wagon) featured an armored horse drawn stagecoach which transported gold and other valuables.
These kind of carriages have some aspects of tanks, but they aren't true tanks like we think of today. They did not carry heavy artillery and they had wheels instead of tracks. They were also much more lightly armored than a modern tank because they had to be light enough to be drawn by horses.
If you are designing a tank which would fit that era, there are a couple of things you would need to keep in mind. Steel was a rare and very expensive material in the 19th century. Iron was much more plentiful. Welding was also rare in the 19th century. It didn't become widely available until the turn of the 20th century. The armored panels would most likely be joined with hot rivets. Iron was, and still is very susceptible to rust, so the panels should be painted.
Since it is horse drawn, you would need to pay special attention to the weight. A team of horses can comfortably pull a carriage 2-3 times their weight over smooth surfaces for several hours without much risk of injury.
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I think this gets into a definition of a tank. Horse drawn artillery is not really a tank...it's artillery, there is quite the difference. Horse drawn artillery such as cannons date back to the 1700's pretty readily, probably further back than that. The horses were not armored and relied on the standard tactics of artillery for defense (stay in the back and depend on indirect fire). Incidentally, it was horse drawn artillery, not artillery fired from a wagon...Artillery comes with quite the recoil and I'm not fully sure if a wagon could hold up to it.
The interesting part that you throw in here is 'Gatling gun'. Ultimately it was these rapid fire guns that did away with horses and cavalry in battle and relegating horses to a transportation role instead. This small gunfire that did away with horses was the driving need behind a tank...something that could resist this small arms fire with negligible effect. Having horses pull around a tank is a bit counter intuitive as the tank is meant to replace the unarmored horse that's pulling it. Had the horse been able to be armored to a degree where it could pull around the tank and resist small arms fire, then the tank wouldn't be needed and you'd simply ride around on the well armored horse.
So a mixed answer for you...when it comes to horses pulling wagons equipped with artillery, then yes...all for that as it's an artillery piece thats not meant to engage in direct fire. A horse pulling around a Gatling gun is also effective as the Gatling isn't very mobile and could use a horses help to get to where it's needed...but neither of these are really 'tanks' by definition. A tank needs to resist the small arms fire that slaughters horses so very well...having your tank dependent on what it's intended to replace isn't very helpful
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Lets take a look at this from an engineering perspective.
We'll take the original Mark-1 tank, the first tank to be called a "tank" (the name came from the fact that they were shipped to the front lines disguised as "water tanks").
It's around 27 tons with a 105 horsepower engine. And it barely managed to crawl with that power. So let's round the numbers up and say that 100 horses can pull a 30 ton tank.
A small 10 ton tank would require around 33 horsepower to crawl slowly.
Leonardo da Vinci's "tank" weighs in at around 5 tons. So let's be generous and say that it could be pulled to crawl slowly with 16 horses. That 5 ton "tank" can barely fit one horse inside it. It was designed to be pushed by humans.
Which means, for horses, it's impossible to build any steel armored carriage to be pulled by horses with all the horses inside the armor. Simply because any size you build would need at lest 10 times the space to accommodate the number of horses needed to pull it.
Any horse-drawn solution requires the horses to be outside the tank.
So it depends on how you want to define "tank". If the horses need to be protected as well then no, it's simply not possible. If you can accept exposing the horses to enemy fire then yes its possible (in fact, as mentioned in another answer, it actually exists historically).
I don't have the calculations for elephants though. Anyone know horsepower to elephantpower conversion?
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A solution similar to a tank (everyone is protected) would require the horses to be inside (or rather underneath) a shell, but horses are not strong enough to carry the weight of the armour plus crew and weapons.
Here you can find a list of the strongest animals <http://www.onekind.org/be_inspired/top_10_lists/strongest/>
What about an armoured elephant? They can carry up to 9 tonnes and there is already history of using them in battle. You could "dress" them with a thick armour, hang gatling gun on the sides and have some one sitting in a cabin on top of the elephant.
Next option would be an ox, or bison. In that case the armour would have to be thinner and the weapons smaller, but could be faster compared to the elephants. The rider could lay on the back (as on a bike) to be enclosed in the armour and have small guns poking out of the shield. The structure of these animals, with a shorter neck than the horse, would facilitate such a solution.
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There used to be something similar called [horse drawn artillery](http://www.wikipedia.org/wiki/Self-propelled_artillery). [barding](http://www.wikipedia.org/wiki/Barding) would provide some sort of protection, but considering the power of guns it would be rendered next to useless. I have no evidence for past use, but I am sure some sort of metal box could be placed around the "charioteers" and the artillery. Holes could be drilled in the sides big enough for a machine gun barrel.
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Leonardo da Vinci dabbled with this and I believe his first thought was that the horses would be inside. Later he rejected that idea because they might panic and replaced it with human power.
[](https://i.stack.imgur.com/ppkHA.png)
[](https://i.stack.imgur.com/0R2Pf.png)
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**[](https://i.stack.imgur.com/5N2re.jpg)**
**Enclosed treadmill**
<http://www.flickriver.com/photos/31068574@N05/15622416604/>
Depicted: the horse treadmill from the Wieliczka Salt Mine in Poland. You could enclose something like this within the tank. The horses would be protected in there. The horses would walk around and around, just like they do in the mine, and the rotary motion would be turned by gears into a motion to move the tank around. Oxen might be even better for this because they are stronger and more docile. If you are worried about them being spooked by war sounds, use deaf animals. Horses do fine without seeing much which is what blinders are for; the depicted horses here have them on.
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[Question]
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## Original question
Imagine we live in a society where humans are completely open-minded and rational about everything. They reason logically and are willing to debate to reach a consensus.
However, even their ultimate motivation is only benefit to themselves, just like us. They too have qualities like us that could potentially be weaknesses, such as hatred, love, fear, etc. but in a more limited extent.
This means that they will make faster communication and better decisions with people when they want to, and be extremely deceptive when they know that their will is against their opponent. This, however, can be brought to light by others more easily. All people know that it is better to get educated.
Would such a society develop in a similar, but faster fashion as ours? Or will the accountability of the political leaders cause them to maybe become pawns at the hands of the people, or will rulers take over nations by force, since deceiving them doesn't work out?
## Clarification
I would like to clarify what I mean about open-mindedness and rationality.
Open-mindedness just means that people will be willing to consider all options (privately, at least) and be more logical in what they think. For example, a Muslim will be willing to consider why his faith could be wrong, rather than just blindly following it. This doesn't mean that the whole world will be following one religion, but study of everything will be more organised.
'Their ultimate motivation is to benefit themselves' doesn't mean they are necessarily selfish. It means that their basic psychology is like ours. For example, if someone feels that they should sacrifice something of their own, in favor of someone they pity, love, etc., that is fine, because the satisfaction they get from helping the other person 'benefits' them. Similarly, there could be a guy who feels no emotions for others and only believes in personal profit, and to fulfill this goal, it might be the best decision logically to even kill someone.
And about feelings co-existing with rationality,.. You could hate someone because you feel they have worked against your purpose in life. However, you are not going to shout at them, fight with them, etc. in a fit of rage, you will first logically think as to whether this is going to, in any way, benefit your pursuit of your purpose in life. If the logical answer is 'yes', you can proceed. And by fear, I meant logical fear. One could be afraid of circumstances and fear for his life, but he will continue to take rational, open-minded decisions to ensure his survival.
*Therefore, feelings will be in 'a more limited extent'. What I mean to say is that the purpose of one's life is undefined. All kinds of people will exist. This won't be a perfect society, just a slightly better one than ours.*
**I am asking how they will progress from a political point of view.** Would kingdoms have existed? What would cause leaders to wage war, and what would the people do? What kind of models of government would have been popular? Will terrorist groups exist, and how would they operate? Will the psychology of the military play a more important role, since they know that the government relies on their united support, to retain a model of government?
[Answer]
You're using words which are difficult to use in extreme situations. It requires some careful wordsmithing, because a naive reading would suggest that your people are, in fact, not open minded to any theory which is not rational. A more exact wording would be "they are completely rational, and openminded to any rationally proven argument."
The second wording is more tricky: "However, even their ultimate motivation is only benefit to themselves, just like us." "Benefit themselves" requires a concept of Self. This causes a problem, but to see the problem we have to define "rational."
If we define "rational" to be defined as "openminded to any argument proven using [First Order Logic](http://en.wikipedia.org/wiki/First-order_logic) (FOL)," then [Gödel's Incompleteness Theorem](http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems) raises its ugly head. It is very hard to define Self without accidentally admitting Peano arithmetic. If you admit [Peano arithmetic](http://en.wikipedia.org/wiki/Peano_axioms), Godel has some very harsh things to say about your system which will generally violate your intuitive sense of what "rational" is.
There are other schools of logic. [Second Order Logic](http://en.wikipedia.org/wiki/Second-order_logic)(SOL) is strong enough to admit a solid definition of Self. Unfortunately Gödel also proved that SOL doesn't admit proofs of any SOL system, unless it can be simplified into a FOL system.
There are an interesting class of systems known as [Self-verifying theories](http://en.wikipedia.org/wiki/Self-verifying_theories), explored by Dan Willard. These can admit a Self and rationality because they sidestep a particular technique used to construct Gödel's Incompleteness theorem. These have very peculiar properties. For one thing: you start with defining an ultimate value (i.e. infinity), and divide and subtract down from there. In doing so, this ultimate value is allowed to be treated as a Self, and every one of your rational individuals acts as part of the Universe. However, it turns out that the rational individuals cannot actually define themselves as anything but "part of the Universe."
The final pattern is to allow each individual to assume their definition of their self. By the [Theory of Other Minds](http://en.wikipedia.org/wiki/Theory_of_mind), they can recognize that others exist, and have the right to think the same way. However, in doing so, it turns out that a language for them to converse in becomes imperfect. Attempts to make it perfect make even more glaring holes to be abused for self-interest. The usual result is the creation of "fuzzy" words which no longer really belong in a rational argument, but become essential for communication during the debate.
This suggests the final variation on the puzzle. Reverse the words: "They are openminded, but temper that open-mindedness with rationality." Sounds quite a lot like society today, if you ask me!
[Answer]
I feel like the premise set forth in this questions is flawed in a few places.
**First,**
>
> However, even their ultimate motivation is only benefit to themselves,
> just like us.
>
>
>
This assumes that all humans are motivated only by their own self interest and that is simply not the case. Open-mindedness and self interest are not necessarily exclusive concepts but they do not mix well together. Being completely open minded would require that people also eliminate all bias, including self bias and an increased value on ones own life versus the life of another.
**Second,**
>
> Imagine we lived in a society where humans are completely open-minded
> and rational about anything they think of. They reason logically and
> are willing to debate to reach a consensus.
>
>
>
and
>
> They too have qualities like us that could potentially be weaknesses,
> such as hatred, love, fear, etc. but in a more limited extent.
>
>
>
are not compatible. You cannot be both completely open minded and rational AND feel hatred, love, and fear as we currently understand them.
**Third**
Humans as we know ourselves today lack the capacity to be completely open minded. That isn't to say people don't WANT to be open minded but to do that you need to consider all possibilities and angles. Humans, out of necessity, lump things into categories, that includes other people, actions, animals, ideas...the list goes on. The point is that lumping things into categories means we may not truly understand many things and you cannot be open minded about something you are also mostly ignorant of. This in our world leads to bias, dehumanizing others, and stereotype.
**TL;DR** Humans as we know them are not capable of being truly open-minded and rational. The sentient humanoids capable of this would have to differ significantly from humans.
**And to address your questions:**
>
> Would such a society develop in a similar, but faster fashion as ours?
> Or will the accountability of the political leaders cause them to
> maybe become pawns at the hands of the people, or will rulers take
> over nations by force, since deceiving them doesn't work out?
>
>
>
Society would develop completely differently (taking into account my points above). Completely rational humans would be more willing to act against their own self-interest. Government would also be be a far more involved process with less conflict (give that this perfect rationality leads all people to the same conclusion). Conflict in its various varieties would also be far less common if it existed at all.
[Answer]
"Don't be hasty"
As others have pointed out, your average human (at least in current Western culture) likes fast and easy answers. Google is a life saver for many of us, including me.
So as a counter to that, a more rational society would be much less hasty for any serious decision. It would also likely encourage long term education for many.
One big problem humans have in general is that we don't like to be wrong. (to different levels about different subjects) How this is a problem is people often will continue to hold a belief and even rationalize away and/or ignore evidence to the contrary when it is held strongly enough. Fanatics are people who suffer from this afflictions to dangerous levels.
So a more rational society would (should) have a much smaller number of people to become fanatics. This includes not only religious zealots and political martyrs, but extreme sports fans, stalkers, and any other place where someone might use violence to 'prove' a point.
A big thing would be people would have to think of better reasons for doing things than what ultimately boils down to 'I want'. I have family members that will by something they can't afford and come up with a dozen reasons why it was a good idea. No, it wasn't, it was a bad idea but they really wanted it, but that isn't a sufficient reason and it makes them sound selfish and stupid.
I think in the financial sector, there would be a lot less volatility, since the 'oil scares' and the ponzi schemers would have a much harder time herding the sheep.
(I'm having a hard time not going into a rant about our current US government) But we have Republicans and Democrats and Conservatives and Liberals and each pair is against the other merely because they are the other. If one side has a good idea it doesn't matter because 'they' had it and we can't let them be right! It would obviously make us 'wrong' then! So like everything else, politically we would tend to be more centrist.
All this rationality would also tend to reduce conflicts including big ones, like wars. However, while we might not kill half a population because they are sitting on a resource we want, we still could be pushed into killing, for more rational reasons. It is also unlikely that there won't be any fanatics, and merely by their reduced commonality they might still be able cause great havoc.
But ultimately better rationality doesn't mean perfect thought or agreement, it means you will likely have much better and factually based arguments to base your reasons on, not just a bunch of made up nonsense used to try and emotionally sway others to your cause.
How would this have come about? Well I have my doubts that a race would 'start' this way. It has to develop. To begin, a race has to 'survive' all the other issues like lions, and tigers' and bears Oh my! So killing to survive will be ingrained for a while, then when famine comes and you don't have anything to trade with, you kill your neighbors in the next settlement to take what they have to live, etc, etc. So where rationality in a race comes in is likely to be late in the game, the 1600s is when our current experiment in rational thought started and we are still working on it. I think we've got another 150 years before rationality breaks into the majority of the populace. So I'm saying it's a process and we are following it, and other species would likely follow a similar path.
(I'll have to reread this later to see if it actually makes sense or if I'm rambling...)
[Answer]
This answer is more of a thought experiment than an explanation based on any sort of evidence, but as we're talking about human nature I think it fits.
First, I think it's important to answer the question, how does it benefit me to be open-minded? You might think the answer to that is obvious, but in reality life is a lot easier if you never have to consider more than one option. Smart people who have not become overly arrogant (which is another form of close-mindedness) are plagued by indecision and the inability to say anything for certain. As with philosophers like Socrates/Plato, no questions can really be answered, they can just lead to deeper questions. This, for many people, is not a rewarding lifestyle; we all want answers, and we usually prefer to get them **quickly and easily**.
Now consider religion. Usually, people are either inducted into religions at an early age, or converted during a particularly stressful time in their lives, when all they want is an easy answer. At some point, the answers offered by religion will provide a **quick and easy reward**, just like how donuts give us a quick and easy source of sugar. In both cases, we become addicted, and come back for more. That's evolution for you: if there's an easy solution, you take it. If you wait around for the best option, you probably won't have kids (at least that's my explanation for why I'm single).
At this stage, I'd like to consider **complacency**. Most people, when they get a good thing, will tend to stay with that good thing. But some people, perhaps the most successful or intelligent people, try and find something better and improve themselves. These people are the open-minded ones, because when they find an answer, they're usually not satisfied with it, and they want more information. They won't accept 'Jesus loves you', they want to know who Jesus was, how he knew about you in the first place, and what manner of love they're talking about (paternal, fraternal, romantic, sexual, etc). This may lead them to question the truth of Christianity, and perhaps to consider other religions. **This is what you want, right?**
Thus, an open-minded society is not complacent. To minimize complacency, perhaps your society was nomadic, moving from place to place in a hostile environment. There would never be long-term safety, so the most important people in the society would be the ones who could quickly change gears and adapt to survive. It would probably also be useful to stick to small tribes/families, as each individual will need to play a larger part in the decision making process. The main problem with this is that usually instability and small communities is counter-productive to development of civilization, but perhaps there's a suitable middle ground.
[Answer]
Question is, if being open-minded and rational gives one group of proto-humans evolutionary advantage over others. And it is not so.
Researchers found that primates can differentiate between members of own group and others. And if forced to change groups (and survive it), primates will make preference to their current group over former. It was found IIRC in rhesus monkey, which has last common ancestors with humans as far as 30MY ago. So this kind of discrimination is pretty old, and this trait seems to be preserved over millions of years. So it will not be easy to dis-evolve (it might take millions of years). Killing males from opposing groups is pretty common between animals.
Being altruistic is different - you are helping your own kin in group (which may share part of your genes), so from POV of "selfish gene" theory, altruism toward relatives is beneficial for gene survival.
Edit: [link](https://books.google.com/books?id=oq4B2WGT9mYC&pg=PA234&lpg=PA234&dq=rhesus+monkey+other+tribe&source=bl&ots=n07Er8SpBp&sig=FxOKRYN-fDk3-XIgTx9hwewUk_g&hl=en&sa=X&ei=sO3sVNDwHYKrNo2mgMgH&ved=0CCsQ6AEwAg#v=onepage&q=rhesus%20monkey%20other%20tribe&f=false) to some different book about violence between primates. [Another](http://greatergood.berkeley.edu/article/item/peace_among_primates) -- [faces of others](http://www.pnas.org/content/106/51/21539.full)
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A society is a living thing that is continuously and constantly evolving, so it has no "perfect" forms. A rational society would be one that tries to use rational and unbiased decision making whenever it is possible, not simply when it is useful or required. We are currently at the "required" level; rational decision making processes are mainly used in science where the process used directly affects the value of the results.
To understand where such a rational society would develop, we need to understand where it came from. What could drive people to abandon the quick and dirty thought processes our brains have evolved to perform efficiently?
Brain implants maybe? Since rational thinking is more complex and uses more resources, it should be possible for future technology to detect whether you are using it and give direct feedback, if you are not when you should be. This would obviously not tell if the data or your thinking is correct, just what form it takes. You'd need training to get anything useful from that.
This might have sufficient value to be adopted by scientists. While science is not really exclusively rational being able to spot "improper thinking process" would help in validating your work afterwards. And reviewing the work of others. And reviewing the assumptions your work is based on. It would also allow verifying that students are using the correct form of thinking, which would presumably help teaching scientific thought immensely. So academia would presumably be in for this.
With wireless connectivity the same technology should also be able to tell if the student is following the teaching, so if cheap and safe enough it might be given to everyone. Or just people undergoing education expensive enough to deserve it. As expense would go down and safety up over time eventually you would get this technology on everyone. Minus some medically or ideologically incompatible small minorities, of course.
This should also be a superior lie detector and it would already be installed on majority of people, so eventually employers and the police would be given the right to verify lack of deception in specific situations. The courts and political process would follow after such "thought verification" had become routine enough to not cause concern. Might take a generation.
Once a deception free society had been established and everyone had become used to verifying their thinking, people would start using it to validate their thinking outside of science. Eventually people would start asking if such validation has been done. It would be the norm and people would think rational whenever possible. This would be a rational society.
And not much would change, really. The society would have higher trust on its leaders since they would be less corrupt and more honest, but the intelligence and competence of people would not really increase as individuals. Politicians might be better able to work together, but they'd still have such as many disagreements arising from their different values. Changing that would require sufficient information to find a correct and shared value system and being rational does not really help there.
Similarly decisions would still have to be made based on incomplete and even incorrect information. The amount of damage might be reduced as people would be more aware of the shortcomings of their information. This might result in more willingness to hedge your bets with compromises that work under several different assumptions of how society will work.
And obviously terrorists would still exist. Terrorism is not really irrational, it is a perfectly rational response to your idea of how world should be not meeting how it is and not having any hope of changing it by constructive means. Openly religious terrorism would probably be reduced. Belief in all-powerful and benevolent God that needs you to kill people to make his will happen is not really rational, so terrorist movements would need to recruit based on their actual reasons not the emotional appeal of fighting for God.
There would be no noticeable change on how the military works. Like the terrorist military would need to recruit and justify itself based on rational arguments instead of emotional appeals. And just like with the terrorists, the reasons always were there. And military forces have always understood that governments stand on their support. That is why in many countries soldiers are made to swear an oath that basically boils down to "support the legit government and political process (please do not participate in a military coup)".
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It is more likely than not that such a society of magically-created (as open-mindedness is unlikely to naturally evolve) open-minded people will be **outcompeted by close-minded people**. Open-mindedness is not a beneficial trait, not at least until survival is no longer an issue (such as being above the median income in a modern day First World country)
A society of open-minded people will engage in rational debate in order to find the best solution. When there is sufficient time to debate this, it is beneficial to the group as a whole, as it allows the global optimum solution to be reached. However, the debates have a significant time penalty.
Conversely, a society of close-minded people will stick with their local optimum solution (which is qualitatively worse than the global optimum). They also do not engage in rational debate, and punish all who propose new ideas. They eschew the benefits of the global optimum solution and save time instead.
If the two societies end up going to war, the close-minded society is far more likely to win, since they will not waste time debating the merits of the best approach forward. In times of crisis, **speed is of the essence**. A society that cannot reach quick, decisive judgments in times of crisis will be easily wiped out.
For the same reason, militaries tend to enforce strict, no-nonsense discipline in the rank-and-file, while at the same time encouraging more creativity and discussion amongst the top brass. A combat unit which does not follow direct orders, instead stopping to debate the best course of attack, is likely to be quickly defeated, whereas large-scale maneuvers which take many weeks or months to execute require the plan to be better thought out, and therefore they often require deliberation amongst panels of generals.
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When looking closer, you'll find that people are actually more rational than it superficially seems, even in instances where they seemingly act irrational. Most irrational behaviour can be traced down as completely rational behaviour, but based on incomplete, and often partially wrong, "knowledge" and believes.
Note that one part of rationality is also to determine whether something is worth thinking about. If you (rightly or wrongly) are convinced that you already know what the result of such thinking would be, the most rational action is not to waste any time on thinking about it. For example, few scientists will be willing to think through a new proposal for a perpetual motion machine, for the simple fact that they know that the laws of thermodynamics forbid such machines, so they already know their conclusion about whether the PM will work or not. The only thing they could get out of this is learning the exact point where *this* proposal fails. This is purely rational behaviour; when considering something a waste of time, the only rational decision (assuming you consider wasting time as bad) is not to do it.
And even in cases where people actively resist to consider obvious counter arguments to their believes, it still is rational behaviour: Since they are emotionally bound to those believes, having to revise it would hurt them. And if you value not being hurt higher than learning something new, the only rational decision is to avoid learning that you are actually wrong.
So what you need for an open-minded society is that all people are, from early times on, come into contact with lots of knowledge, and lots of experiences. Especially they must come into contact with contradictory claims, and experience the failure of some of their own assumptions. This would make them more likely to consider finding their believes to be wrong as normal way of life and nothing to be hurt about, and decrease the probability that they emotionally attach too much to their believes simply because their experience tells them they are often wrong.
One problem is that small children are naturally born believers, for the simple fact that you have to start with some believes if you want to learn at all (if you start with questioning everything, you'll not come far; even Descartes did not *really* question everything, for example, AFAIK he never questioned that if there is thinking, there must be someone who thinks). But while inevitable, it also is a vulnerability because at that age you can implant them a believe that certain things are not to be questioned. And if you believe that certain things are not to be questioned (especially if those things include some entity that punishes you for questioning those believes), the only rational(!) decision is not to question them.
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If you're ok with giving it a few hundred years, you can go with an evolutionary answer. If close minded people have fewer (or zero) children, the population can become genetically inclined to far more open mindedness. Intense selection pressures can significantly kick in within just a few generations, and can have a strong impact in probably ten to twenty generations.
Close minded people could be more likely to die, or they could produce fewer children, or their children could be less likely to survive, or it could be simple mate selection. You can't have kids if no one wants to mate with you. On one hand mate selection can be influenced simply by social ideas on what constitutes a desirable mate, but you could also end up with close minded people simply pairing up with each other. That could result primarily in polarization among the population, rather than more open-mindedness.
If you're looking for a faster solution... pardon my cynicism and dark humor but this is related to the above answer...
The only reliable means of rapidly opening a closed mind is a bullet to the skull.
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After some generations they would become utterly crazy due to believing in all kinds of idiotic theories. Being open-minded by itself cannot guarantee good ideas, neither pure conservativeness can do it. Its a - very hard to attain - mix of conservativeness and open-mindedness that guarantees intelectual evolution. Besides most of the time where a civilization clinged to a obsolescent concept, this was not due to pure lack of open-mindedness. The church did not kill those who believed the earth was spherical out of pure lack of open-mindedness, but to prevent those ideas from exposing the flaws of church ideology, wich would foster people to start questioning church and nobility privileges.
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I imagine a society filled with Ender Wiggins. In some respects, we should expect it to look a lot like our society right now. There would still be Taylor Swifts and Kanye Wests, but their fans would not be fanatical. They would be the moms and dads of today's concerts, rather than the screaming teenagers, and they might go to concerts as much out of a sense of irony as any particular love of the music.
There would be political parties, but the parties would appeal to the highest thinkers rather than the lowest. Instead of just promising to give away stuff to the masses, they would try to claim that their vision of the future is the most accurate, and extends the furthest. The debate would not be about whether climate change is anthropogenic, but rather which allocation of resources most appropriately deals with the near and far-term future. Credibility would be based on analysis and information-gathering, rather than pandering.
If actual fanatics existed at all, they would do so as a higher-order tactic to achieve an obscured goal. Every major action would have a double-, triple-, quadruple-meaning and intent. The world would be a giant game of chess. If someone committed an act of terror, it would cause real terror, not because it is random, but because everyone would know that it is carefully calculated, and you either understand the cause (and can avoid a similar fate), or you don't (and you are already behind the curve).
Some people would still choose to be homeless or vagrants or hippies, but probably very few would be low-wage workers, because they would realize in school that the path which leads to drudge work does not optimize personal happiness (in the future...of course, it usually is the result of consuming all the happiness in the present).
On the one hand, cooperation would be maximized, because there are many situations in which it is rationally optimal but not chosen because of irrationality. On the other hand, this would make more appealing targets for high-functioning sociopaths, who are necessarily rational and open-minded (because ultimately, cooperation requires trust, and trust is the primary currency of sociopaths).
I would guess that this world would be both more exciting and more terrifying. Human value systems would likely change more quickly, and we might view this society as barbaric in some respects. They might decide that eating dead people is perfectly acceptable and a good way to recycle resources. It might look like an extreme form of libertarianism. In many respects, it may look like a lot of cyberpunk societies.
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I'll try to take the question on its meaning, rather than nitpicking about words and definitions (which doesn't mean some other answers were not very interesting and enlightening).
My core assumption is that historically speaking, we have evolved to be more open-minded over time, especially since the Enlightenment brought rationality to a pole position. So all we need to do is extrapolate the current trend.
Looking at historic developments, we see several areas where close-mindedness has been overcome in current society. The belief that all humans are equal is reasonably recent and still not completely realized. Older societies are full of women/slaves/foreigners/unbelievers - basically everyone-who-is-different-from-me having less rights, lower status, etc. etc.
We also see the open brutality is closely linked to this ability to label "the other" as something less-than-human. While the western world today is without a doubt brutal on the 3rd world with exploitation and child labor and pollution, etc. - this is hidden brutality and wherever it comes to public attention, there is a scandal and actions to reduce it are started. But open brutality like public executions, war against civilians, torture, etc. seem to depend on a certain close-mindedness and would probably not exist in a completely open-minded culture.
I'm quite sure religion wouldn't exist. The whole psychological foundation of religion is basically "here are all the answers, stop thinking".
The next area is taboos. Every culture has them, and they always seem to fade away under rationality and open-mindedness. In the western world, sexuality is a topic largely covered in taboos, so I will use it as an example. While many of us today consider homosexuality a little creepy and disgusting (come on, admit it, we're all humans), the thought that gays should be put to death is far from most of us. Other parts of sexual taboos and restrictions are breaking up as well. Cheating isn't punishable by being stoned to death anymore. Open relationships are not yet quite acceptable to society, but if you have one you don't find yourself a total outcast anymore as well. "Deviant" sexual interests are largely accepted as long as you keep them mostly to yourself (it's ok to have them but they're not dinner talk subjects).
Compare that to medieval times where most of the stuff that journalists explore in person for a middle-of-the-magazine article would've seen them and their family put to death, you can see where I'm going. An open-minded culture would be accepting to different styles of fashion, art, music, sex and possibly drugs.
So basically, imagine hippie culture and square it, and you have a first impression.
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Is it possible for humans to live on a world with the following conditions?
**Atmosphere**:
* 50% nitrogen;
* 30% oxygen;
* 20% carbon dioxide.
**Climate**:
* The rain in some areas is acidic. (Is there some factor other than air currents that affects the creation of polluted clouds and its rainfall?)
* Temperatures between -5 ° C and 30 ° C.
**Flora**:
* Some more robust plants than Earth survive the acidic waters and produce oxygen, along with some seaweed caves with pure water.
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Assuming atmospheric pressure is similar to Earth sea level, the number that immediately jumps out is **20% carbon dioxide**. This is far above levels in Earth's atmosphere.
According to the wikipedia page, [symptoms of hypercapnia](http://en.wikipedia.org/wiki/Hypercapnia) include diminished vision, shortness of breath, sweating and unconsciousness at 8% CO2 in the air. (Earlier symptoms include drowsiness, headache, confusion, increased heart rate, etc.)
Other than that, the percentage of oxygen is within the range of what existed in Earth's atmosphere during the [Carboniferous period](http://en.wikipedia.org/wiki/Carboniferous), so I doubt that would be a problem. Temperatures are within the range found on Earth. And you mention that pure water is available.
So if humans live on this world, I think their first concern (by far) would be scrubbing CO2 out of the air they breathe, and their next concern would be whether the "robust plants" that tolerate acidic conditions are edible.
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CO2 is way too high. Possible effects:
* Change of PH (acidification) of blood. BAD for all of the body chemistry.
* Replacing oxyhemoglobin with [carbaminohemoglobin](http://en.wikipedia.org/wiki/Carbaminohemoglobin). Reduced transport of oxygen by the blood, even with the increase of the oxygen % in the atmosphera.
* Levels of CO2 in blood is what causes the "reflex to breathe" (the urge that you have to breathe when you are suffering Apnea). Chainging the base level from 0.03% in Earth's atmosphera to 20% would be unworkable. <http://en.wikipedia.org/wiki/Apnea#Complications>
* Apart from that, the rise in the level of oxygen is also not good (remember, pure oxygen is **toxic**), but pales in comparation with the issues due to CO2.
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Mmm, in a 30% oxygen environment, [human hair](http://papers.sae.org/2009-01-2512/) and some fatty human tissues would burn like a paraffin torch at the smallest spark.
Not that you would much care at that point. The 20% CO2 (=200,000 ppm) would have you [unconscious and dying](http://www.cdc.gov/niosh/idlh/124389.html) in minutes.
Funny thing, most of the rest of the universe is far, far more hostile to humans than the environment you describe. So, with gas masks glued to their faces (and absolutely no smoking) they might survive for a while, especially if they can build (fireproof) controlled environments where they can, for instance, safely take off the masks to eat, drink and complain about being sent there.
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**Yes, absolutely**.
In fact, assuming *Earth-like atmospheric pressure*, that is a relatively welcoming environment compared to most of the rest of the universe. We would be very lucky if Mars had such an atmosphere. Humans will, though, need some sort of breathing apparatus when outside as (has been pointed out) the amount of CO2 you describe would be toxic, and appropriate shelter depending on what you mean by 'some rain is acidic'. But otherwise the temperature range is quite pleasant, having O2 in the atmosphere is good (might actually be a bit high, but irrelevant since you can't breath the atmosphere directly anyways), and even the CO2 might be conducive to plant growth.
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Another problem (beyond already mentioned way too high CO2 - which would also cause greenhouse effect and baked the planet, a MAJOR problem) is low N2 (minor problem). Many plants use N2 from atmosphere, it would be harder to do that.
Ocean would be more acidic and food chain would be very different - most small animals would not be able to build shell in such acidic water. Ocean would be ruled by jellyfish and algae.
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**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
In the climax of a story I'm writing, the antagonist is flying high in the sky(she has wings) during a thunderstorm, while wearing a full suit of armor. She is struck, and nearly killed. But lightning is only attracted to things touching/connected to the ground. Could being attached to the ground(through a rope tied to her ankle or something) make it work? She is the only one injured by the lightning strike.
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As far as lightning is concerned, *everything* is connected to the ground.
Lightning is a brief one-way current from the ground to a cloud (or sometimes the opposite way). That current is going to preferentially go through good conductors (like metal armor and humans) instead of bad conductors (like air). Lightning *can* go through air, obviously, but if there's a large conductive object in the vicinity, it's probably going to go through that instead.
Presumably, your character doesn't have armor covering her wings. In that case, I think the most likely path for the lightning strike to take is to go in one wingtip and out the other. She's going to have a bad time. Even if her armor is made of metal, it isn't going to help her here, because the lowest-resistance path from one wingtip to the other goes through her body, not through the armor.
If your character is much luckier, the lightning strike could go entirely through the armor—perhaps into the helmet and out through a shoe. In that case, I think that she'll be totally unharmed by the discharge itself. A lightning bolt only carries about 15 coulombs of charge, and the worst that 15 coulombs will do to a large chunk of metal is to heat it slightly.
The armor won't change the fact that a lightning bolt just struck through the air above and below her. I don't know what the effects of that on her would be; at the very least, it would make an extremely bright flash of light and an extremely loud sound.
(The protective effect of metal armor is sometimes described as a Faraday cage effect. I don't think that's accurate. A Faraday cage blocks electromagnetic radiation by completely enclosing something. A lightning strike isn't electromagnetic radiation, and armor doesn't have to completely enclose you in order to have a protective effect—theoretically, a single wire would work just as well. So, a suit of armor may protect you from lightning, and a suit of armor may act as a Faraday cage, but those are two distinct and not-very-closely-related properties of a suit of armor.)
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A [lightning](https://en.wikipedia.org/wiki/Lightning#Lightning_leaders) discharges through the path of minimum resistance.
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> In a process not well understood, a bidirectional channel of ionized air, called a "leader", is initiated between oppositely-charged regions in a thundercloud. Leaders are electrically conductive channels of ionized gas that propagate through, or are otherwise attracted to, regions with a charge opposite of that of the leader tip.
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> The positively and negatively charged leaders proceed in opposite directions, positive upwards within the cloud and negative towards the earth. Both ionic channels proceed, in their respective directions, in a number of successive spurts. Each leader "pools" ions at the leading tips, shooting out one or more new leaders, momentarily pooling again to concentrate charged ions, then shooting out another leader. The negative leader continues to propagate and split as it heads downward, often speeding up as it gets closer to the Earth's surface.
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> Once a conductive channel bridges the air gap between the negative charge excess in the cloud and the positive surface charge excess below, there is a large drop in resistance across the lightning channel.
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> A large electric charge flows along the plasma channel, from the cloud to the ground, neutralising the positive ground charge as electrons flow away from the strike point to the surrounding area. This huge surge of current creates large radial voltage differences along the surface of the ground.
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A connection to ground is not strictly needed, as a human body can be less resistive than the equivalent length of air, acting therefore as a preferential channel for the discharge.
It is somewhat similar to how airplanes get sometimes struck by lightning despite not being wired to the ground.
For sure having a physical connection to the ground will make it for a higher chance of being hit, if it would lower the resistance of the path (e.g. wet or conductive line)
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Being hit: **Plausible.** Surviving it: **Plausible?**
You might be interested in the [story of Zhongpin He](https://www.smh.com.au/national/lightning-killed-paraglider-20070221-gdpifu.html), who was sucked into a storm while paragliding and later found dead. Lots of things could have killed him but post-mortem examination revealed he was killed by a lightning strike.
Apparently [9 out of 10 people survive lightning strikes](https://abcnews.go.com/Health/people-survive-struck-lightning/story?id=57241207), though injuries can be varied. The biggest danger is cardiac arrest and no one around to deliver CPR.
I couldn't readily find a story of someone being struck in the air and surviving but I don't see why it would be worse than being struck while on the ground (other than the no CPR thing, but not all lightning strikes result in cardiac arrest either -- some end up with [no apparent injuries at all](https://www.weather.gov/safety/lightning-survivor-story-glenn)). Probably just a roll of the dice if it kills you or not. Burns are a common injury, but of pretty random extent (I found stories of anything from no burns to 3rd degree).
But!
Since we know it can strike [paragliders](https://en.wikipedia.org/wiki/Paragliding) in the air (that's where you're just kind of sitting under a parachute type thing), and we know it's possible to survive a lightning strike, I think your scenario is plausible, and you can give her injuries of anything from severe burns to literally no problems at all.
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Lightnings routinely hit airplanes while high off the ground. This is generally safe and the worst damage is some paint getting burnt. If something goes wrong, this is because the pilot is temporarily blinded or disoriented.
If there are conditions for "almost" create a lightning, a conductive object near the possible lightning path can facilitate the electrical discharge by shorting the path as well as concentrating the field lines near its extremes.
From the lightning viewpoint, a bare human body is almost as good a conductor as a metal piece. Wood, concrete, wet stone, chimney smoke - everything is better than air in this regard.
No need to tie your antagonist to the ground in order to get lightning, but it can help a lot. It will be a very high lightning rod.
In regard to survivability:
I can't imagine how wings and full suit of armor play together, but if the wings are covered with metal, we are generally in the airplane hypothesis where the metal protects what's inside very well.
On the other hand, touching the same metal in more than one point and/or bad electrical connections between the metal parts can make the lightning strike over the metal deadly or at least very much shocking (because of the voltage drops over the resistance). There are simple measures that can get your armor lighting-proof, but these should be done in advance and require knowledge.
Even if everything else goes well, the metal parts will get rather hot to touch (20..100kA of the garden variety lightning are not a trivial engineering task) and even worse near joint points. Parts may simply weld to each other in the joints. Not good for aviation.
And then... there are quite a few things in a thunderstorm cloud, besides the lightnings, that can kill someone. Like, e.g. gusty and turbulent winds that can stress your body mechanically up to tearing it apart. Ice pieces in the few kilogram range (pretty much normal, this is what hail looks like when inside the cloud core) aren't safe either.
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Related solution to the wing-armor-survivability issue is to just have metal covering over the main joints of the wings that connects to the rest of the suit, kind of like flashings but for wings.
It would allow the current to never actually go *through* the wings, because the metal armor will attract the current better than wet plumage.
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**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.
Quick drawing illustrating what I mean:
[](https://i.stack.imgur.com/0ezSg.png)
Two people (humanoids, between 1 and 2 metres tall) are standing on the ends (less than 1km from the edge) of opposite faces of a flat world (approximately 20km thick) and staring out into space. One of them describes the constellations they are seeing: a wolf, a feather, whatever people see in stars. Can the other person see the same stars?
I imagine that no matter the distance separating the two people, the answer will always be "Yes, as long as the stars are sufficiently far away", so I guess then the question becomes: how far away do the stars need to be in this situation?
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## Depends on how close to the edge they are
[](https://www.flickr.com/photos/alexpanoiu/52442474275/)
Overlapping fields of view of two observers on opposite sides of a disk world. The field where both observers can see an object is purplish sector; note that the farther away from the edge they are, the narrower the common sector is. Own work, [available on Flickr](https://www.flickr.com/photos/alexpanoiu/52442474275/) under the Creative Commons Attribution license.
For clarity, let $h$ be the height of an oberser, $H$ the thickness of the disk, and $d$ the distance of the observers from the edge.
The angular size of the overlapping part of their fields of view is $$\alpha = 2 \arctan \frac {h}{d}$$
In the question, $h$ is given as 2 meters; so that
* if they are 2 meters away from the edge, the common field of view covers 90°;
* if they are 20 meters away from the edge, the common field of view reduces to 11°;
* at 200 meters away from the edge, the common field of view narrows to 2°; and
* at 1 kilometer from the edge the common field of view is a thin thin thin sliver of about 0° 14ʹ.
The distance $D$ between the edge of the disk and the nearest object which can appear in both fields of view is $$D = \frac {dH}{2h}$$
from considerations of similarity of triangles; in the question, the thickness of the disk $H$ is given as 20 kilometers, so that
* if the observers are 2 meters from the edge, the nearest object which they can both see is at 10 km from the edge of the disk;
* if the observers are 20 meters from the edge, the nearest object which they can both see is at 100 km from the edge of the disk;
* if the observers are 200 meters from the edge, the nearest object which they can both see is at 1,000 km from the edge of the disk; and
* if the observers are at 1 kilometer from the edge, the nearest object which they can both see is at 5,000 km from the edge of the disk.
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The part of the surface going from their feet to the edge will shield vision of part of the sky, so their field of vision will only partially overlap, as you can see in the below schematic.
[](https://i.stack.imgur.com/hNjsK.png)
The shorter the distance from the edge, the larger the overlap. The limit, with both observer standing on the edge, would be the half sky in front of them. A would see something above their head which B would not be able to see because it would be under their feet.
In formulas, calling $d$ the distance from the edge and $h$ the height of the observer, they would miss a portion of $arctan (d/h)$ of their field of view due to the presence of the bottom. Their common arc of view would then be $\pi - 2\cdot arctan (d/h)$
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# Same Constellations?
Yes, they would see (practically) the same constellations along the band of sky they can both see. I assume this is the area you are talking about.
Otherwise, this is a trivial question: they would see different constellations outside of the swath of sky they share because there is a (another assumption!) sight-blocking planet between the two viewpoints. Since the internet has its fair share of pendants who take joy in pointing out the obvious, I ought to include this for completeness.
# How Far Until They're Different?
It depends. How far away are the stars? Are any visibly close to each other? How much movement in stars' position qualifies as "different?"
There a phenomena called "[parallax](https://en.m.wikipedia.org/wiki/Parallax)." This is the driving factor for change in constellations in this question. Astronomers use this (and the Earth's yearly trip around the sun) to calculate distances of far away stars. Wikipedia informes us that heliocentrism was argued against because the parallax effect wasn't particularly observable at the time. This is, of course, no longer the case!
We could have stars easily disappear if they are (visually) close to another. However, for an observer on a non-megastructure planet (like Earth!) this isn't likely to happen. You can play with some numbers to figure things out a situation which works...
Consider, however, the sky as seen from our nearest star [Alpha Centauri](https://en.m.wikipedia.org/wiki/Alpha_Centauri). Astronomers have calculated that the sky looks nearly the same at 4.37 *light years* away!
The take away here is that, for most sizes of things we consider terrestrial planets, even if it is disk-shaped, these two observers will see the same constellations. They would need to be radically far away to see anything different. (With the caveat of "while looking at the same section of sky.")
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How “flat” is this planet? Earth is flattened out a bit by its rotation and a planet spinning much faster would be much flatter. While the Earth orbits the stars in the sky shift because the axis of rotation differs from the axis of the orbit. Through the year a person anywhere on Earth could likely see all the same stars as someone else anywhere else on Earth. These two people might have to climb a small hill and/or clear out some trees to get a good view but it seems to me everyone on this planet will see all the same constellations.
If the axis of rotation, axis of orbit, and a few other parameters are such then it is likely that there are portions of the sky in which someone on one side can’t see what someone on the other side can. I’m thinking of the North Star and Southern Cross, two points of navigation in the sky. These points are helpful for navigation because we know what they look like and that they closely approximate the Earth’s poles painted in the sky. People in the northern half of Earth generally can’t see the Southern Cross. If close to the equator, at the right time of year, and on a hill or in a ship’s crows nest, then the Southern Cross is visible.
If the North Star and Southern Cross, or this flat planet’s equivalents, can both be seen where these two people are then it would appear to me that they see everything the other sees, just not at the same time.
How far away would a star have to be to be visible by both people? My guess is it has to be far enough away to not irradiate them to death. Dead humanoids aren’t going to be stargazing.
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Humanity is on its last lap. A once great empire has been reduced to a single Dyson sphere around the dying sun, and most of the matter of the solar system has already been incorporated into this last bastion of survival. Any activity which leaks energy out of the sphere is suspect, and only very rarely do humans venture outside anymore, on occasional expeditions to salvage stray asteroids or other rubble.
In this scenario, the only way space travel could be considered acceptable at all is if it can be performed at an extremely low energy cost, so that the energy gain of towing in an old shuttle or piece of rock surpasses the expenditure of making the trip in the first place.
My thought is that a type of travel that could be conceivable in this world would be using laser sails to travel outwards, and then falling back towards the home sphere through natural gravity. Heat inefficiencies from the lasers themselves could be absorbed back into the sphere, and the kinetic energy of the ships could be reclaimed on return.
Is this feasible? The ships can be assumed to be almost fully contained and self-sufficient and able to sustain a small crew for months or years. Some energy/heat leakage will be unavoidable, but is it possible that you can still go energy-positive through such a scheme, or is it just utterly ridiculous? Speed and comfort can be sacrificed, since we're talking about squeezing just a few more years of sustainable living from a solar system which is already at the limit.
If not reasonable based on what I laid out here, are there other options which could work better?
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The biggest issue with energy loss is stopping at the destination. A fuel burned to produce thrust will be pointed directly away from the Dyson sphere. Since mass is energy, the loss of any mass is the loss of energy. Barring that, there are a few options.
One method of reducing energy loss is for each departing ship to have a giant mirror on its rear. More speed is imparted by reflecting light than by absorbing it. In a perfect world, light could be generated by a high-energy laser, bounce against the mirror to impart speed, and reflect back to energy collectors on the surface of the sphere with zero loss. Even with some loss, it would result in minimal loss for maximum gain, but this is slow. The loss would increase over distance as lasers are not perfect, but they are decent enough. There would still need to be a method of stopping at the destination, but something like a solar sail might be a viable option, as the light from the approaching star would increase as the ship approached, providing more deceleration the closer it got.
You could also accelerate the ships along a magnetic track built across the outer surface of the sphere. This would allow for a constantly increasing acceleration until extreme speeds are reached. When the ship achieved its target velocity, it could simply release its magnetic clamps and be flung outward.
A fusion drive could potentially provide energy to the sphere, but it would still be at an overall loss. The drive plume from the ship could be concentrated into a laser type emission and directed at energy collectors. This would allow the energy from the drive to be collected. As with the laser reflector, there is bound to be some loss. There is also the loss of the energy mass of the fusion fuel needed to stop. The energy from burning the fuel to accelerate could be captured, but the ship will be pointed the wrong way when it wants to slow down.
You could throw rocks at the ship. Well, maybe not rocks, but metal slugs, so... bullets? The ship could capture them in a magnetic field, stealing the velocity and taking it as its own, and then fire the slugs back towards the sphere, providing additional thrust. The ship would need to carry enough slugs to slow down in the end, but the thrust generated would be higher due to the higher mass of the slugs. Light has very little mass. Robotic factories could be sent ahead of the ship to start building mass drivers and slugs for when the ship approached, eliminating the need to carry additional slugs for slowing down.
Honestly though, your people should just fix their star. Star-lift material from its surface, extract everything except the hydrogen, and cool it down a bit. Heck, even keep some of the extra hydrogen and convert the star into a long-lived red dwarf. Every few billion years they could toss back in some hydrogen and keep it going for a while. Big stars burn fast, while small stars burn very slowly. If they have overcome the technical issues which plague a Dyson sphere (which was never meant to be a solid structure, but a swarm of smaller satellites) then they should be able to mend their dying sun. Although, now that I think about it, perhaps they already star-lifted the extra material from their sun and used that for their sphere. If they are running low on hydrogen, they could resort to electrolyzing their oceans and pouring that hydrogen back into the sun. A Dyson sphere's worth of water is a ton of hydrogen. Heck, just do away with the sun altogether and install a few thousand fusion candles to provide the light and heat you need. More energy efficient in the long run to change the light bulbs than to keep using a star for something so simple.
If you were to reduce the size of your scope to a planet-sized sphere with everyone living on the inner surface and held down primarily by spin gravity, the problem could be the lack of hydrogen for the fusion candle used to light the sphere. The "sun" is dying from a lack of fuel, and you have a ticking clock to race against. Such an object could potentially be traveling through the depths of space (maybe inter-galactic), far from an easy source of hydrogen for refueling. This eliminates the technical issues with Dyson spheres and could still provide a similar backdrop to tell your story.
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# In space, there is no free lunch
If you're thinking that waiting for gravity to bring you back is reasonable, then a solar sail option is inefficient and unreliable. You don't have an atmosphere to worry about, so just use a mass driver. If the Dyson sphere is fully contained, your worlds tech must have a way of redirecting the solar winds into vented plumes, so that would work.
After that, everything falls apart. You'd need a method of matching speeds with the target once you get there, or you'd crash into your target at high velocity. If you're thinking you'll do something to cushion the impact, you have to account for around 50kps, compared to a typical bullet's speed of .5kps.
Let's say you have super-strong materials, and you're talking about a rock smaller than your ship. You could grab it with a net on a tether, at which point you and the object would be orbiting each other like a thrown bola. If you draw the object in, the speed of rotation increases, eventually splattering the inside of the cabin with the human occupants.
You can use gyroscopes to slow down the rotation, but then you're using the same amount of energy as if you'd matched speeds with it. Maybe a little less because you're making the rock match speeds with you instead of the other way around. If it's a really small rock, you'd be ok. If it were something bigger than you, it wouldn't spin when the tether pulls on it and you'd swing into it and hit it even harder, like with tether-ball.
So you've matched velocity and grabbed/docked/landed on your target. Now both you and the other object are moving at the average of your momentum. Since you're adding "moving away" energy to the combined mass, odds are you aren't on a trajectory to intercept your home sphere, so you need thrust to change your trajectory.
So, from a modern human perspective, there is no way to make this a low-energy process. You'd have to apply whatever magic is used to keep the Dyson sphere from collapsing.
## Dying sun
On this point, I have to ask what you think a dying sun looks like. As it burns through the hydrogen, the helium core increases the density of the remaining star, increasing gravitational collapse, making the star burn faster and brighter. Our Sun has been increasing its luminosity by about 10% per billion years.
When the Helium starts burning, things get even worse. The outer portion of the star will expand into a red giant. You can imagine what that would mean for a Dyson sphere.
Maybe you're thinking of really, really far into the future when the Sun has become a white dwarf? Why would mankind return to huddle around the ashes of its old star if it's already been to so many others? Mankind would have had to go elsewhere to survive the red giant phase.
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# No
* If natural gravity could pull the ship back to the Dyson Sphere, it would already be pulling the asteroids the ship was sent out to get.
* This process would be insanely slow. What value could anything inside the solar system have that would justify years of travel and the energy expense to move the ship?
* You've harnessed the energy output of a sun. The amount of energy needed to move a ship effectively is beyond the measure of irrelevant compared to that scale. If humanity's energy consumption actually brought the issue to bear, it's no longer relevant that the ship can fly because nothing it can reach or recover can solve the problem.
* If you're so nervous about energy consumption that you'd consider using laser sails to move a ship, you'd be insane to try to move any object more massive than the ship out of its trajectory for a useful purpose. In reality, said object can't be anywhere near as massive as the ship because the force of the trajectory is the problem. F=mA.
# But, should you care what I think?
No! I apologize for being a bit brutal, but you're basically asking us for permission to use an idea. Plausibility, reality, feasibility, etc. are all nonsense. How many people among your audience have the background to read your story and say, "wait a minute...." And of that handful of human beings, how many would be mean enough to stop enjoying the story to bring it to your attention?
OK, it has happened before. When [MIT students stormed the venue at the 1971 World Science Fiction Convention](https://www.theguardian.com/books/booksblog/2010/jul/02/larry-niven-ringworld) chanting, "The Ringworld is Unstable!" Well, they did it.
*But what a badge of honor!*
People cared enough about your story to take the time to test it! Jeez, they're a bunch of losers compared to your creative genius! Therefore, please remember that this Stack's purpose is not to give you permission to use an idea, but to help you solve a problem that you cannot solve yourself. You've already solved this problem — you're just unsure about your solution. It's great! I love it! It would make the basis of an interesting story about subsistence living at a time that should be post-scarcity!
So, throw all of us the proverbial vulgar hand gesture, go write your story, and enjoy the wonder of your world!
*<Bah-Humbug Mode Off>*
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Since this is a very high tech society, and presumably the bureaucracy only cares about the net energy or mass that is returned to the sphere.
Perhaps they temperature regulate the sphere by controlling and regulating the electromagnetic radiation by controlling the emissivity of the external surface in sophisticated ways including being able to direct the radiation to the spacecraft with the sails. They might even up-convert the radiation to visible or UV wavelengths, and make it coherent (Laser) to improve the sails efficiency.
To return, perhaps the sails have controllable diffraction gratings which might help steer the spacecraft, but more importantly since they are collecting mass, perhaps they have a fancy drive that converts the collected mass to energy.
Since the bureaucrats only care about the net return on the energy and mass balance they are allow to use that mass to energy conversion for an ion drive, and return home. Even small amounts of mass would suffice since $E=mc^2$ could potentially return a lot of energy.
It might be that some elements are easier to convert than others, hydrogen in ice easier than iron.
You would have you choice of handwaving technologies from it being fusion as we know it today, or perhaps some other as yet undiscovered technology converts atoms or protons etc to energy.
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As others have mentioned, stars don't die in the way you seem to be describing. The stellar objects that do slowly cool are already quite "dead"...that's why they're cooling. It's also hard to reconcile the possession of a Dyson sphere with an energy shortage...a more typical problem is finding enough matter to usefully do stuff with the energy.
Aside from that, photon propulsion of any kind is essentially the limit of how far you can go with increasing exhaust velocity to reduce propellant requirements at the expense of higher energy requirements. Laser sails are thus one of the *least* energy-efficient propulsion options you could consider, the only thing worse being to put the laser on the spacecraft as a photon rocket. The energy consumption will be vastly more than anything you could recover from kinetic energy of the returning spacecraft.
At least, this will be the case for sails outside the sphere. Inside the sphere, the reflected and slightly red-shifted light will just be absorbed by the inside of the sphere. If you are truly energy-limited, you could do the majority of the launch inside the sphere and recover most of the energy used as scattered and slightly red-shifted laser light.
The spacecraft could then use low value materials as propellant to do the relatively undemanding rendezvous maneuvers in the outer system and send objects back home, obtaining more reaction mass from them along the way.
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I'm afraid you're out of luck on this one.
The "sails" must be completely absorptive, since if they reflect the laser energy you'll get stray reflections running around the interior of the sphere until they hit something.
For an absorbing sail, in order to provide one pound of force you need (in rough numbers) about 2 billion watts of power. So, for instance, if you want to boost a one-ton payload to a speed of 96 feet per second (about 60 mph), and you want to do it in 10 seconds, you'll need a laser with a power of about 1.2 trillion watts. Since you've stated that high-energy or high-power is off the table, I don't see how it's going to work.
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**Angular Momentum is Not Your Friend**
The method to go in and out sounds good. Subject to the efficiency rating of your solar sails of course.
The problem is you need more energy to get that asteroid back home. Asteroids orbit the Sun just like everything else. They are moving very quickly in a circle. To get them into the same circle as your Dyson sphere you need to speed them up or slow them down. That takes energy.
By the way how does your Dyson sphere not fall into the Sun? A Dyson circle could just orbit. But the same thing doesn't work in three dimensions.
Perhaps you can plant solar sails in the asteroid and then sail it home like a sailboat.
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If you're trying to predict the future, that might be scientifically feasible but roughly when do you hope suitable technology will be developed?
If this is fiction, it sounds far less unfeasible than the average "Fire up the FTL drive and let's get out of here…"
If this is fiction, the real limit to "feasibility" is the writer's ability to make a case.
For a vaguely similar example, take whichever episode of Star Trek: Deep Space 9 has the Siscos making a Kon-Tiki-like expedition in a hand-built reconstruction of a primitive, light-sailed space-ship. As I recall, that wasn't just inter-planetary, but capable of travelling between systems!
The major difference there is between laser- and sunlight and who's going to argue that might almost as well take up pin dancing with the angels.
I suggest DS9 got away with it purely because the quality of writing and production lured the audience into suspending their disbelief in the half-baked "science."
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I see you've already accepted an answer, however I wanted to share some additional information. Per [this](https://physics.stackexchange.com/a/14702/338182) answer on the physics stackexchange, you can approximate the time it will take any craft to fall back to the Dyson sphere (assuming the Dyson sphere is not too much larger than the Sun itself) with the following equation:
[](https://i.stack.imgur.com/Y5IrS.png)
where t is time (in second), r is the distance from the sphere (in meters), G is the gravitational constant 6.6743E-11 and M is the mass of the star you are falling towards (in kg). In the case of our Sun, that gives you a simpler formula:
[](https://i.stack.imgur.com/sgtc5.png)
Note that as r is raised to the 3/2th power, return times will become very long if you want to go far out. Here are some examples of times it would take to fall to the Sun from different distances:
* Mercury: 2 weeks
* Earth: 2 months
* Asteroid Belt: 7-12 months
* Jupiter: 2 years
* Saturn: 5.5 years
* Kuiper Belt: 30-60 years
In other words, returning to the Sun using only gravity is not a solution that will work in all cases.
Also, note that you cannot get too close to anything larger than a small asteroid without getting pulled into their gravity well. So planets, moons, and larger asteroids are off-limits unless you have fuel and an engine.
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# The sail ships are pushed home by exterior lasers
If the the timing of their system-wide mass sweep is planned well, they could intentionally leave several dwarf planets or other large masses remaining in the distant reaches of the solar system outside the sphere, and place laser sources (perhaps just more mirrors) on them to push sail ships back home. Any objects interior to these remaining laser emplacements are accessible by sail. Timing is crucial, because the dwarf planets should be in decaying orbits to counteract the transfer of momentum and keep from being ejected in the long term. They should still fall sunward faster than they push in reverse, so that in the end they are the final mass collected in the system. Thus the sail ships start collecting mass as far out as possible, moving inward as the dwarf planets fall.
In other words, **a gravity-powered return trip is made feasible by using large external masses as intermediaries.**
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## Dying stars aren't weak and low-energy objects
Don't think that the Sun is just going to fade into oblivion. Instead it would swell up into a behemoth, engulfing the Earth in the process. It would possibly swell as far as Mars. Sure, the surface might be as cool as a red dwarf. But its core is going to be superhot, like 1,000,000,000 kelvins hot.
[](https://i.stack.imgur.com/8RXTz.png)
When the Sun exhausts its hydrogen supply, it starts burning helium in its core, which releases much more energy. This causes the sun to expand in volume, so as to increase surface area to release more heat. I believe your solar sails can work more efficiently, in this environments, along with your Dyson Sphere
Image credit: [Astronomy Magazine] 9https://astronomy.com/magazine/ask-astro/2020/09/what-will-happen-to-the-planets-when-the-sun-becomes-a-red-giant)
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The context is a spacefaring civilisation decides to dump its refuse and biomatter into space. Due to a technical error, the biomatter doesn't fall into the nearby star but instead finds a stable orbit around it. Or it finds itself in a lagrange point, maybe one which protects it from the star's solar radiation. With enough organic material, it would become the size of an earth-like planet.
If the biomatter being launched into space is thick enough, then I envisioned it acting like a spaceship for bacteria, insects and small mammals. They would be protected from the elements by the flesh and biomatter and would also have instant access to stores of food. Those that survived the trip would merge with the rest of the flesh planet.
With enough mass, I saw the decomposition of the flesh by the bacteria would allow for an atmosphere to form. Life would then be able to burrow itself to the surface and live on a flesh planet. With constant dumping of flesh and biomatter, I was hoping that the planet would maintain the same physical characteristics of flesh.
Would this or any similar scenario be possible?
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An answer to a sort of similar question has been provided in [XKCD What if 4](https://what-if.xkcd.com/4/)
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> **What would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place?**
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> Mammals are largely water. A kilogram of water takes up a liter of volume, so if the moles weigh $4.52×10^{22}$ kilograms, they take up about $4.52×10^{22}$ liters of volume. You might notice that we’re ignoring the pockets of space between the moles. In a moment, you’ll see why.
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> let’s gather the moles in interplanetary space. Gravitational attraction would pull them into a sphere. Meat doesn’t compress very well, so it would only undergo a little bit of gravitational contraction, and we’d end up with a mole planet a bit larger than the moon.
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> The planet would start off uniformly lukewarm—probably a bit over room temperature—and the gravitational contraction would heat the deep interior by a handful of degrees.
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> The mole planet is now a giant sphere of meat. It has a lot of latent energy (there are enough calories in the mole planet to support the Earth’s current population for 30 billion years). Normally, when organic matter decomposes, it releases much of that energy as heat. But throughout the majority of the planet’s interior, the pressure is over a hundred megapascals, which is enough to kill all bacteria and sterilize the mole remains—leaving no microorganisms to break down the mole tissues.
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> Closer to the surface, where the pressure is lower, there’s another obstacle to decomposition—the interior of a mole planet is low in oxygen. Without oxygen, the usual decomposition doesn’t happen, and the only bacteria that can break down the moles are those which don’t require oxygen. While inefficient, this anaerobic decomposition can unlock quite a bit of heat. If continued unchecked, it would heat the planet to a boil.
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> But the decomposition is self-limiting. Few bacteria can survive at temperatures above about 60 °C, so as the temperature goes up, the bacteria die off, and the decomposition slows. Throughout the planet, the mole bodies gradually break down into kerogen, a mush of organic matter which would—if the planet were hotter—eventually form oil.
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> The outer surface of the planet radiates heat into space and freezes. Because the moles form a literal fur coat, when frozen it insulates the interior of the planet and slows the loss of heat to space. However, the flow of heat in the liquid interior is dominated by convection. Plumes of hot meat and bubbles of trapped gases like methane—along with the air from the lungs of the deceased moles—periodically rise through the mole crust and erupt volcanically from the surface, a geyser of death blasting mole bodies free of the planet.
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**If couched in Lovecraftian prose, then yes.**
I propose you live up to your moniker, Felix. Set aside your astrophysics and biology knowledge; someplace you can find it later. Then get reading - dig in to that Lovecraft and break it up with Rime of the Ancient Mariner and a little Poe. Then take yourself back a century and describe just as you propose, but lean into it. Fantastic horrific flesh worlds are fine Lovecraftian horror fiction.
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When matter the mass of Earth clumps due to gravity, about 2\*10^32 J of gravitational potential energy is turned into heat. (That is the gravitational binding energy of Earth)
The Earth has a volume of 10^12 km^3. Flesh is basically water, so this flesh planet has a mass of 10^24 kg.
It takes 4000 J to heat 1 kg of water by 1 K, so 4 \* 10^27 J increases the meat-planets temperature by 1 K.
So this places the planet at 50,000 K. Which is, of course, ridiculous; what really is going on is that this measures how much heat the meat planet has to bleed off in order to form.
The resulting structure isn't going to be very biology based. Biochemistry will be sterilized.
Now this flesh sphere will not have the same density as Earth; it will be about 5 times less. That lowers binding energy for the same radius by a factor of 25, so down to 2000 K. So you'll end up will a bunch less heat to bleed off. But it will still far surpass sterilization levels.
The material will differentiate, and you'll get a core of solid carbonish stuff wrapped in a boiling ocean, above which you'll have a mostly steam atmosphere with impurities.
The body has to be pretty small not to boil. A way of looking at it is that any "planet" sized body got hot enough to melt the rocks that formed it into a sphere, and that requires less heat than sterilizing flesh.
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## Randel Monroe's Mole of Moles essay does not apply here
The Mole of Moles essay assumes that all of the biomass is added at once in the absence of outside forces, meaning the stuff in the middle will not be able to decompose, but this planet is formed through accretion over time which yields a very different outcome.
Depending on how close you are too the star, this biomatter will either be frozen or cooked by the star's radiation before accreting. Since your civilization was aiming for the star, I will assume that you looking at very close orbit like mercury allowing most of the biomass to be very thoroughly cooked before it accretes. Cooking the biomass means that most of the gaseous elements (Like Hydrogen, Oxygen, and Nitrogen) will be liberated from the biomass and pushed off into deep space by solar winds while the less easily vaporized elements like carbon, calcium, and phosphorous will remain behind. This will result in an orbiting cloud of ash BEFORE it can come together to form a planet.
Over time this ashy cloud will form into asteroids that will collide forming bigger and bigger asteroids yielding increasingly energetic impacts until you get something big enough to sweep the orbit forming a planet. Since the new planet's core is non-ferrous, it will not form a magnetic field to protect it from solar radiation; so, any last remnants of water vapor or other gasses released will be quickly blown away into space. It also lacks enough radioactive isotopes to maintain a molten core; so, the core will quickly cool down and harden making it volcanically inert.
This will basically leave you with a planet made up of about 85% carbon, 7% calcium 5% phosphorous, 1.5% sulfur, and 1.5% other stuff.
In the birthing stage of your planet, rapid powerful accretion impacts will cause crystallization and shattering to occur meaning that your planet will likely have a regolith surface similar to the moon, but instead of being made mostly of oxides and silicates, it will be made mostly of things like graphite, diamonds, calcium carbide, and calcium phosphate.
So, to answer your question about the viability of life, you are missing many helpful ingredients like an atmosphere, magnetosphere, water, etc. However, the planet will contain a high volume of industrially useful compounds not widely found on normal planets; so, you may find intelligent life showing up to mine the place...
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So, I have a country in the making in my series that has a completely different culture than the rest of the world other than belief in a religion, Prophiatism.
Since the country is said to be so different and also is the heaviest place of belief in Prophiatism, almost to the point of it being a cult, could they survive as a country if they did not have any political leaders, saying this in the sense of a titled leader such as king or president?
To apply some more context, this country is called Ebrias, and Ebrisian people automatically hang, or execute by bullet, any person in their country who they find does not believe in Prophiatism at all or speaks against it. This would mean any person who could possibly cause trouble inside the country by changing other's minds on the subject or just blatantly trying to take over would be stopped before they can make any effect.
But, on the other side, since Prophiatism is also known throughout the world and is commonly followed and that Ebrias is considered the heart of the religion because of the religions lore, what would stop other countries from invading and taking over?
My answer to that isn't clear but, in my thoughts, there is a god in the Prohpiatism pantheon who is a god of war. I was thinking maybe there would be a group of people in the society that choose to heavily follow this god in the pantheon creating a sort of small army with them maybe training to fight to worship that god. This would be the same with farmers following the fertility god, etc.
But still with all this, would this country still be able to survive in the world with a structure like this?
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Yes, the religion becomes the government. This is known as a theocracy, and is not rare in history. Early Islamic history shows that Muhammad engaged in both religious preaching and politics. North American colonization also shows clear elements of this, as many of the early colonies were founded specifically as havens for persecuted sects. In the absence of strong, local secular governments (the nominal government being weeks away by ship), religious leaders ended up taking on much of the necessary governance tasks. Look at the Puritan movement in New England for endless examples of this.
In your specific case, you mention that "Ebrisian people automatically hang, or execute by bullet, any person in their country who they find does not believe in Prophiatism at all or speaks against it." What you have is an informal vigilante group or militia, which can easily become institutionalized into a law enforcement agency or criminal justice system if the leaders of Prophiatism encourage the members of said militia to formalize their ranks. This could be through the introduction of standardized training regimes (delivered at Prophetiatistic monasteries by clergy appointed for such), the induction into religious orders of militia members (with the associated rules and discipline associated with belonging to such an order), or the establishment of penalties for fighting for Prophetiatism in a manner "unauthorized" by religious leaders.
E.g. something like the following decree could get things started:
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> Any follower who has acted or desires to act in favor of the Prophetiatistic religion may submit their resume to the local bishop, who, upon his recommendation, may send the follower to Three-Year Crusader Training Camp at which they will be indoctrinated into Level II Prophetiatistic Foundations in Preaching and Intermediate Introduction to Advanced Best Practices in Religious Police Organizational Technology, upon completion of which said follower will be inducted into the Order of the Iron Fist of the God of War.
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In just a few sentences above, a few things have been established that are commonly associated with governments:
* An educational system, with defined entry and exit points
* An organized service agency, with official selection/vetting criteria, which may act as a de-facto military, police force, and/or judicial system
* A way to enforce uniformity or discipline (the Order of the Iron Fist presumably has rules that must be obeyed, or possibly even uniforms to wear)
If you are uncomfortable with having a single agency handle everything, then you can divide it. Make the members of Order of the Iron Fist who have completed Crusader Training Camp into police, and establish a separate religious order to act as judges for alleged blasphemers brought in by police.
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**No**
There is such a thing as a theocracy, but a theocracy is defined as one where the *government* is run by priests or other religious figures - not that there's no government at all. And government of *some* sort is always necessary. Who will build and maintain public roads? Who will deal with the advent of natural disasters? Who will solve disputes between two people and pass judgement on criminals?
And, suppose, that your religion Prophiatism has an answer to all those question and has a framework to deal with large-scale events. Well, guess what? *That's a government.* So, either your religion has a government build it, or the people form one outside of it, but a government is absolutely needed to avoid the country falling into chaos and ruin.
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Other answers:
Robert Columbia:
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> Yes, the religion becomes the government.
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Halfthawed:
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> ... a government is absolutely needed to avoid the country falling into chaos and ruin.
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I disagree. While a theocracy is certainly one possibility you can consider, I don't think it is mandatory.
If you have a strong church organization, that church will become a de-facto government if there is no other.
But you don't need a strong church. A charismatic leader can gain influence in one city, but will not have much to say elsewhere. Maybe there is even a religious prohibition against taking religious leadership, like with the Quakers.
What is needed to defend against internal chaos is a strong culture. If everybody agrees that a nice well-ordered society is a good thing, the few criminals will be branded unbelievers and lynched.
Lynching should not be too common, as that in itself leads to unrest.
There will need to be some sort of system for settling civil disputes, but it doesn't have to governmental.
Defending against external enemies is different. I would suggest something like fear of excommunication. Not actual excommunication, since that requires a central authority, but more like informal word-of-mouth shunning.
Some hundred years ago the leader of Oppressia decided that they could waltz in and take this ungoverned area. At first it seemed easy. The army marched in and declared the county conquered. Hurray!
But then soldiers started disappearing in the night and turning up dead. Not very many, but the rest became very nervous.
At the same time, Oppressia's trading partners suddenly stopped trading with them. Their economy took a steep dive.
Then important people start dying in the capital of Oppressia, usually killed by their own servants. Not very many, but the rest became very nervous.
Some weeks later the leader is killed in a coup. The next leader immediately orders the withdrawal of the army and things return to normal.
Still, Oppressia haven't really recovered from this yet.
[Answer]
### It depends...
...on how you define "government". Since you did state that you want them to "survive *as a country*" (emphasis added), then they are going to have to have *some* kind of leadership.
...and "politics" is what happens when you put two or more people in contact with each other. A bunch of anarchists each doing their own thing will *not* have any cohesion "as a country", and once you give them any sort of decision-making capability *as a group*, then, guess what, you've given them government!
So...
### No
If you take a literal meaning of "government", then government (i.e. political leadership, even if that leadership has nothing to do with "public works") is absolutely necessary for any sort of group identity to maintain itself, *especially* if there are any external problems (e.g. other entities that want to take your stuff).
However you also asked:
>
> Would this country still be able to survive in the world with a structure like this?
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>
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...and mentioned:
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> Could they survive as a country if they did not have any political leaders, saying this *in the sense of a titled leader such as king or president*?
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(Emphasis added.)
Well... yes, and probably not / it depends. They can survive; theocracy is not at all implausible. However, they will almost certainly have titled leaders. They might call them "judges", "bishops", "reverends" or whatnot, but people being what they are, it will be difficult to avoid saddling the people that are in charge with titles. The only way I could see this happening is if they have some really strict religious proscription against titles, and even then, the leaders are going to be titled *in fact* if not *in name*.
### By the way...
Did you know that churches *have government*? If you look at the Roman Catholic Church, or even any of the more organized protestant denominations, you'll find they have government not unlike a large corporation or small country, with various levels of officials and usually a single person acting as the chief official ("president", "pope", etc.). A cohesive religious body the size of a country is almost surely going to have government *in its own right*, regardless of whether the church *also* functions as the *state* government.
[Answer]
At various times in history, stateless countries have existed. They tend to be perceived as primitive and some of that perception is justified in that this often happens in places where humans are still tribal hunter-gatherers, but not all of it is valid. Most people today have a bias in favor of governments, if only the idealized versions they imagine in their own head.
Statelessness, as a condition, is a little difficult to pin down. When it does work, it's not always clear what factors are at play. I don't believe religion to be a requirement at least from those examples we have, though it wouldn't necessarily be a hindrance either.
We might even compare this place to Somalia or Afghanistan. There are many disincentives to invading such a place. The United States decided to perform "police actions" in Somalia in the 1990s, and this caused significant political grief. Somalia had no strong government (little at all), it had no regular military. There were people who wanted that police action to succeed, and perhaps even future ones to similar locales to happen in the future. But the results were a PR disaster that turned off that administration to further adventurism.
Afghanistan wasn't quite so different (though it did have a singular person in the undisputed top status). There, the United States did invade and remained, but we must consider that the prize there was significantly more valuable encouraging them to ignore these disincentives.
These examples, drawn from modern history, shouldn't make you think that it'd only be true on 20th/21st century Earth. Wars and invasions were often ruinously expensive unless victory promises to be self-financing (there's enough loot to make it worthwhile).
Additionally, if you're proposing a militia of some sort, that's not implausible either. They are probably the norm in those places with a weak or remote government.
My conclusion: there are no details here that make your story entirely implausible, though you will need to carefully navigate them to suspend disbelief and bring it all alive for the reader/player/whichever.
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[Question]
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In a story I am writing there is a being with Superman level strength, flight, the ability to produce lasers, and survive in space. He has decided to solve the mineral crisis by finding and grabbing an asteroid and taking it back to earth so that it can be used to build lots of cool things and green tech.
They have the backing of an eccentric billionaire, and moderate political will in support of them, and modern earth technology.
How would they best, with brutal physical strength, flight, and lasers get that mineral wealth from space to earth?
Some constraints- they can, essentially forever, produce 200 megawatts of power for use in flight or lasers.
Their flight doesn't require notable reaction mass.
They are durable enough to survive space and high accelerations essentially forever, and air isn't a concern.
They don't have magical forcefields to make asteroids stay together or behave.
Ideally, humanity will be functional as a civilization by the end, with no world ending impacts. Props to any answer which involves less loss of human life, or none.
To summarize- how could a being with 200MW of power eternal best harvest asteroids?
Edit. As JBH noted, science based questions don't have to have fully plausible scientific questions, the answers have to be plausible. That said, you can replace the superman with a 200MW fusion spaceship if you prefer with lasers and flight.
[Answer]
**There's good news and bad news. First... the bad news**
*The lasers are almost useless*
Have you ever picked up dirt clods with your hand? Have you ever picked up a lot of them? It's a slow process. It wouldn't matter how super-strong or super-fast he is, anything's more efficient than picking up dirt clods — and that's what lasers would make of the asteroids, dirt clods.
The only reason to use them is to quickly knock away huge chunks of less-valuable rock to get at the more-valuable rock.
However, if there's so little valuable material in asteroids that you're regularly knocking off huge chunks of less-valuable rock, then using the super strength to get stuff out of the ground of good old Earth would be more efficient. Remember, it takes time to get to asteroids.
**But, there's good news!**
Your superperson can haul a *net.* A big, honking net[Obligatory XKCD](https://what-if.xkcd.com/56/) made out of steel cable. A net that would allow him to haul a whomping big bag 'o asteroid home with him. This is good, because 200MW will haul almost any amount of asteroids home. The problem isn't getting them back to Earth orbit.
It's getting them down from Earth orbit.
*Maybe the lasers have value after all...*
How much energy do we have to work with? Let's do some quick math. Let's assume superdude's a buff and beautiful 235 pounds (106.6 Kg). He's gotta go 7 miles a second (11.3 Km/s). OK, F=mA, we need 1.2e6 Newtons of force. Basically, newtons = watts, so 1.6MW are needed to get up and he'll need the same to get down unless he's planning to land in the ocean or make a hole someplace.
That gives us 198.4MW to work with. That means he can land 13.2 metric tons of material. The price of gold will plummet.
**And that's really good news! Well... not the price plummeting part...**
What this means is that superdude can put the bag 'o asteroids into orbit, then shuttle 13.2 metric tons of it down at a time. All he needs is (literally) a world-class net or bag.
*My father would be proud! I got my money back and nobody got [hurt].* ([Source](https://youtu.be/BaXkCmxkG7I?t=3005))
[Answer]
The best way to solve the mineral crisis isn't to get the asteroid to Earth but to get the equipment from Earth into space to allow the harvest and processing.
The cost of getting materials into space is around $25K a kilo. If Superman provided an cheap taxi service to get people and materials into space, people could go get their own asteroids.
[Answer]
**Supernaut - How to cheat at Space Exploration**
Supernaut is functionally free Delta-V with a brain.
He can easily go anywhere in the solar system without any additional equipment and carry a payload with him, that's fantastic in every sense of the word.
The best thing Supernaut can do is learn the engineering requirements to maintain space hardware so he can just go out and deal with ad-hoc problems without a multi-billion dollar expedition.
Even without specialist knowledge, our super-astronaut provides the incredible service of being able to physically go fetch defunct or damaged satellites and bring them home for repairs before putting them back.
If you're not keeping him busy with big projects, Supernaut can easily go land instruments and equipment on practically every body in the solar system, you want to know what that bright shiny spot on Ceres really is? He can go fetch a sample of the water-ice there and bring it back for your coffee.
He can physically carry a box containing a mars rover, set it on the martian soil, open it and leave again. No more huge rockets for tiny payloads.
Cubesats? He can carry a crate of them and deploy them anywhere in the solar system for free.
Supernaut can very easily go prospecting for useful minerals and bring back samples so you can decide whether mining there is worthwhile too.
Supernaut's spare time can be filled accelerating fuel and cargo pods into Hohmann trajectories to resupply missions throughout the solar system. Essentially free Launch Delta-V means that they can simply carry enough to perform their deceleration at the other end and rendezvous with whatever they're there for.
**What about Asteroid mining?**
With the savings on the smaller missions, nearly all the budget can go into the construction of a modular mining spacecraft which Supernaut can carry in sections and help assemble in orbit.
The actual flight to the asteroid can be conducted conventionally with the ship running uncrewed on automatic, our Supernaut can then ferry the crew in a small car-sized passenger module and take far far less time to do it.
This negates most of the challenges of keeping a crew alive for the months it might otherwise take to get to the asteroids.
Remember that Supernaut can be under power continuously the whole time, a week at most to rendezvous with the mining ship in a craft comparable to the Apollo Orbiter is pretty acceptable.
If sending a crew to mine asteroids doesn't appeal though, you can still have Supernaut ferry boosters out to the target asteroid so it can be pushed into a more accessible orbit remotely. Having Supernaut do the pushing will be long and tedious compared to setting up something more slow-burn and leaving it alone.
**In Conclusion**
Asking Supernaut to physically mine or even to fetch asteroids would be a staggering waste of potential.
Really your only concerns as NASA Administrator is in keeping Supernaut happy and busy. Pay him whatever he asks, because it's bound to be cheaper than doing things conventionally.
[Answer]
Okay, so according to [this](https://phys.org/news/2008-12-asteroid.html) article, the rotation needed to break apart the average asteroid is equivalent to one revolution every 2.2 hours. Doing some quick math, I found that the maximum acceleration an asteroid could withstand under these parameters without breaking up is 8.157 \* [asteroid radius in meters] meters per hour squared, or 0.000000629 \* [asteroid radius in meters] meters per second squared.
To put that in perspective, if the superpowered being wanted to move the largest known asteroid, Ceres, with a radius of 476 km, the maximum acceleration that it could receive is 0.299 meters per second squared. Considering Ceres is about 2.77 AU away from Earth (4.1439 \* 10^8 km), it would take 1664880 seconds to move it to Earth (about 19.25 days). However, at the end of this, it would be moving 497799 meters per second (0.001 of the speed of light).
If instead the super hero went out and got the smallest known asteroid, 2012 DA14, with a radius of 10 meters, in 2013, when it passed within 27000 km of Earth, the maximum acceleration would be 0.00000629 meters per second squared, it would take 2930030 seconds to get here (about 34 days), and it would be moving only 18.430 meters per second when it got here.
So, in conclusion, if your superhero wanted to transport an asteroid, they would either be able to safely get not enough material here, or get a sizable quantity of material at a far too dangerous speed.
[Answer]
An individual is going to have a very hard time harvesting asteroids even if they are super powered. It would be better if they just redirected a bunch of asteroids towards earth, moved them into stable orbits then lowered them all onto the planet.
That way, he only needs to travel back and force once between the asteroid belt and earth to deliver many asteroids, and by lowering the asteroids back to earth, he can retain all the current mining and manufacturing equipment which will be able to process the materials in the asteroids much better than any single human would be able to do.
He just does the hard part. Getting that comet that could wipe out the planet from space and into the hands of industry.
As a bonus, he could also dump all the waste materials on the planet into the sun for much cheaper than rocket launches and since he can replenish the material we dump into the sun, we don't need to worry about running out of resources (until our super hero leaves or gives up).
[Answer]
Working with simplified physics, 720GJ per second, after 10s and disregarding gravity, assuming 90kg... 7200GJ=45kg\*v^2 => v = sqroot(7,200GJ/45kg) or 4Mm/s or slightly over 0.001c
That means they can move fast.
Realistically, physics gets wonky at high speeds. Maybe they could use an array of space mirrors to melt asteroid surfaces and change their orbits. Maybe they could fly out to the asteroids and change the orbits there. Really, it depends on far too many factors: how much food they need, how far the target is, how much mass the target has, the velocity vector of the target, the technology available to the civilization, and so forth.
I recommend not explaining whatever madness you are angling towards here and leaving it up to the reader-- or just having them sit on some electricity-generating bicycles. It'd be a lot simpler...
[Answer]
Have your superman use his strength and/or lasers to produce electricity, and then use that energy towards whatever normal means people in your world would use to mine asteroids in the event they didn't have a superman to assist them. Even if you don't have a way to launch things into space with electricity, you can probably use that electricity to produce everything needed for the rockets and so forth.
Some other answers suggest having superman carry stuff into orbit, but he's going to be slow at it. You said he has 200MW at his disposal, but the power output of a Saturn 5 rocket is in the 83,808MW range (111,744,000 hp \* 750 watts/hp) <https://www.quora.com/What-was-the-horsepower-and-torque-of-the-Saturn-V-rocket>
So, he could do it in theory, but more slowly, and only one at a time.
This has the added benefit of not making the mining operation completely dependent on superman should he be temporarily needed for some other more pressing task like saving the world, and any technologies developed to do the mining can then be scaled up as new energy sources become available.
<https://www.smbc-comics.com/comic/2011-07-13>
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[Question]
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The [Bay of Fundy](https://en.wikipedia.org/wiki/Bay_of_Fundy) sees the world's highest tides, with ocean water advancing and withdrawing as much as 20 meters or more within a single day.
[Here is a list](https://tidesandcurrents.noaa.gov/faq2.html#26) of the 50 tidal stations around the world with the highest tides, all with average tidal ranges of over 7 meters. Note the location of these tidal stations: they are in Canada, United Kingdom, Alaska, Argentina, France, Chile and Russia. None of these locations are anywhere near the tropics.
I want a great tropical river delta, like the Ganges delta, to empty into a sea with massive 10m or more tides. The river will collect waters from a wide swathe of savanna, and be highly seasonal in flow; a great monsoon season will increase flow rate by a factor of 10.
**With the least amount of physical changes from Earth, how can I get 10 meter tides or more at a tropical river delta?**
* I want the tides at this delta to be exceptional, so tides elsewhere on the planet must be roughly equivalent to Earth's.
[Answer]
### The tide travels in a constant wave around the world
Of course that's a simplification, but it's a useful one for the moment because we're going to look at [wave interference patterns](https://www.physicsclassroom.com/class/light/Lesson-1/Two-Point-Source-Interference).
[](https://i.stack.imgur.com/X13yk.gif)
If we consider the Bristol Channel, which is fairly well represented on your list, it's on the back of a large island relative to the wave of the tide. That means it gets two tidal waves, one comes round the island from the North, the other comes round from the South. The Bristol Channel just happens to be in a location where the two tides meet at a point of constructive interference.
As a counter example, at Southampton on the South coast of England, the tides around the Isle of Wight miss the point of constructive interference at the port but don't quite hit destructive interference. This causes a complex tidal system with a double peak and some very strong currents round the island as the tide first flows in first from one side of the island and then from the other.
Tides around the UK are particularly complex because of this effect and the currents can be very dangerous. Add a high wind, which can hold a tide in or out, and things get considerably more difficult.
The reason for the high tide in [Alaska is different](https://tidesandcurrents.noaa.gov/faq2.html#27).
>
> The tidal range of a particular location is dependent less on it position north/south of the equator than on other physical factors in the area; topography, water depth, shoreline configuration, size of the ocean basin, and others. For example, let's consider the southern coast of Alaska and British Columbia. The configuration of this coastline is very similar to a funnel, with the narrow end at Cook Inlet. The tides travel as a "wave" across the oceans, and in many other respects act as a "wave"; this type of configuration tends to accentuate the "wave" at the narrow end of the funnel. This is part of the reason for the large tidal ranges, 30+ feet, in the area of Cook Inlet. If you look at the tidal ranges for stations on the Bering Sea, outside this funnel but at the same latitude, you will find a tidal range of 5-7 feet.
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[Answer]
I guess the reason why high tides are seen in those places is strongly related to their geological history.
To have high tides you need to have a sort of funnel shaped coast line, that compresses the sides of the tidal wave as it propagates, increasing therefore its height.
In regions affected by the ice age, it is possible that the rivers have carved deep valleys when the sea was much lower, or alternatively the glacier itself carved those valleys and left them behind upon melting.
Those valleys now, with an higher sea level, behave as funnels and give high tides.
I guess that in the tropical regions the glaciation didn't have the same effect, either because there were no glaciers or the reduced availability of water didn't allow the rivers to deeply carve the coast line (those closer to the glacier could still count on the melting water coming from the glaciers).
I would say that having a formerly glacial region being migrated around the Equator by plate tectonics would be a suitable way to achieve high tides.
[Answer]
The Bay of Fundy gets especially high tides because the shape of the bay (with the level of water in it) acts as a resonator almost precisely tuned to the frequency of the Atlantic tides outside the mouth of the bay.
It's not just the general appearance of the bay on a map, it's also a matter of the three-dimensional shape of the bay, including the depths at various points.
But if you could somehow have a basin the same shape as the Bay of Fundy much closer to the equator, and exposed to the same frequency of tides, you would likely have a very large tidal range there too.
From the very next question on the web site you linked:
>
> Q: It appears that the range of the tides gets larger the further the location from the equator. What causes this?
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> If you only consider a few locations, this may seem to be true; but it is not the case. Literally hundreds of locations in the extreme north and south latitudes have small tidal ranges, and a number of stations closer to the equator have large tidal ranges. ...
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So latitude is not a problem, per se.
## But ...
To have a large river delta you need a river that meanders through silty soil, picks up a lot of silt, and slows down as it reaches the sea so that it deposits the silt around the river mouth, forming the delta.
It might strain credulity of some readers to have such a silty river slowly emptying into a basin of the shape of the Bay of Fundy. How is it that we have Bay of Fundy topography just beyond the mouth of the river but Mississippi topography everywhere upstream?
Another thing that might strain credulity: you have a 10-meter tide washing over the delta once or twice a day, necessarily causing fast currents to carry all that water in and out, yet the rushing tidal currents do not wash away the delta.
The last part is what I find most difficult to believe.
[Answer]
**There are two solutions: lunar orbits, or geography**
**Lunar Orbit:**
The simplest way to allow greater tide changes in the tropics **without altering the Earth**, is to simply alter the moons orbit instead. Change the orbit so that the moon orbits directly over the equator. Currently the moon's orbits is 23 degrees displaced off of the equator, which leads to the highest tides also being 23 degrees displaced since that is where the tidal bulge is the greatest.
[](https://i.stack.imgur.com/ifDL6.gif)
Altering the moon's orbit so that the highest point of the tidal bulge instead occurs over the equator is the conceptually easiest (*and most absurd*) solution.
**Geography:**
The second contender is altering the geography of the tropics. One of the biggest factors contributing to tidal variation is geography.
Specifically we see that the highest tides tend to occur in areas where the geography of the land constricts the ocean; bays, narrow channels, etc. What is happening is the land is essentially funneling the rising water and these areas have exaggerated tidal variations. Where there is less constriction and more open ocean, the tides are less exaggerated.
*So have more land in the areas where you want more tide, or change the orbit of the moon.*
<http://www.astronomycafe.net/FAQs/q2792x.html>
<https://www.quora.com/Why-are-tides-lower-at-the-equator>
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[Question]
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This one’s a bit of a stretch, so bear with me. The classic monster in table top games and video games alike: a monster that can imitate the shape of things (mostly treasure chests) to lure in people to eat.
For those who are unfamiliar with mimics, their classic natural form is an opaque brown amoeba that secrets a super-glue like substance. In feet (hah), it's 5 by 5 by 6... which makes treasure chests convenient for them to imitate, since they're of similar dimensions. When adventurers approach the "treasure chest," the mimic reaches out with a gluey pseudopod and grapples the adventurer, eventually consuming their victim.
## So, is it possible for these to exist?
[](https://i.stack.imgur.com/dBBMV.png)
<https://roll20.net/compendium/dnd5e/Mimic#content>
<https://www.dandwiki.com/wiki/5e_SRD:Mimic>
<https://www.dandwiki.com/wiki/Mimic_(5e_Race)>
There's and entire genre of monsters like this in D&D. The following video is a great intro to them.
<https://www.youtube.com/watch?v=Yz4M3Vqbt7U>
[Answer]
### In *theory* it could evolve... however, it would take a long long time.
It's possible that a somewhat chest shaped (but not looking creature) hiding in a darkened room could be mistaken at first glance by a human, and this trait is what evolution picked to continue forward and over a few thousand years those traits continued to succeed. Thus it became more chest looking, but it would still probably only work in a darkish room, where the mistaken identity would be easier.
But there are a few other options:
### Does it have to be natural?
If magic was the answer then this would be easy, but even without magic, selective breeding can yield the required results a lot lot faster than conventional evolution. Maybe some organisation wanted a treasure guard, and so over a hundred or few hundred years selectively bred a creature to look more and more like a treasure chest. This has been done with racing pigeons a long time ago I admit, but a pigeon breeder (can't find the article now) over a hundred years ago said he could give you a new breed of pigeons in 25 years.
Now these would still be pigeons, but they would look different enough to be classed as a new breed, same thing here. But it is only so quick with pigeons because they have such a fast reproductive cycle.
You need the organisation to want to create this crature and to spend the time selecting the correct traits to breed them and *hope* that those traits as passed down. And then once they look close enough, breed the aggression into them...
### Does the chest have to be alive?
It's a stretch from you original concept but have you considered creatures such as hermit crabs? They find existing items and turn them into their homes, they'll find suitable sized shells that are naturally around the world and then get inside and walk around. It has been documented on a few occasions that they will climb inside empty food cans. It's possible that another creature could have evolved that needed the space of a treasure chest, i know this is not exactly the same thing as the chest itself actually being a live creature, but it's a possible workaround...
[Answer]
Octopuses shape shift, and could squeeze into a form resembling a chest. Chameleons and octopuses control their coloring. Make them intelligent enough to identify human-crafted objects and imitate them.
An issue you'll face is its hard to walk around without solid bones. So your creature doesn't move a lot. It evolved by imitating fruit trees that different animals were drawn too. It can also likely emit scents. It camouflages itself like a rock, and striking like an alligator when a foolish deer comes too close.
As a result of humans hunting to kill it and trying to in turn prey on humans, it grew intelligent enough to notice human-crafted items such as chests and imitate those. It grabs nearby sticks to prop itself up to a square-like shape.
The idea that a competent adventurer knows these exist, sees one, and doesn't realize is a bit of a stretch, but should pass in a book as long as the creature doesn't use the same shape every time. In reality, it would probably imitate rocks, or cover itself in leaves and mud instead.
As for the glue, that's easy. Spiders create glue. Your beast could easily make a gluey saliva, or one with neuro-toxins as well, and spit it on its prey.
[Answer]
Mimicking something harmless or even mimicking something desireable to the prey item, or even mimicking the prey item itself are all tactics used by various specialized predators in nature. Could an organism evolve to look like something we would be attracted to in order to eat humans? Its not impossible, just very very unlikley.
For a creature to evolve specifically to fool humans by disguising itself as furniture would imply that it had spent millions of years lurking within human settlements evolving along side us. It might make for a fantastical fantasy device, but I just cant see any plausible scientific explanations for a creature that looks like a manufactured human item. I can see stuff like an inviting pool that is really a colony of neurotoxic ameoba functioning like a super-organism or something. I just cant figure out how to explain something that looks enough like a wardrobe or a chest or something to fool a human.
The only semi-plausible way I could explain such a thing without a lot of hand waving and "magic" would be a nanite swarm, but now were talking robotics instead of anatomy.
[Answer]
They don't mimic, they appropriate.
the manga Delicious in Dungeon has a great take on mimics. They are basically giant terrestrial hermit crabs, they appropriate larger and larger objects to hide in as they age. in dungeons or cities large ones often use furniture like chests or cabinets. They are ambush predators waiting until darkness or something disturbs the to move. They always match the environment because they use things from the environment.
Honestly the series is a great take on how to make dungeons and monsters functional and plausible.
You don't have to use hermit crabs but a similar behavior where the creature uses existing furniture as a shell the same way hermit crabs do will be the most believable way to have them look like different man made objects. WHat the exact anatomy of the creature is is more open and depends on how you want them to attack, long tentacles and a sharp beak for biting could come from some kind of terrestrial mollusk a "hermit octopus", or something like an "**Hermit Otyugh**" might work even better.
[](https://i.stack.imgur.com/WY5AQ.jpg)
[more mimics](https://www.mangapanda.com/dungeon-meshi/13/13)
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I don't see the amoeba part working in real life. I could see the mimic evolving out of an alligator snapping turtle or an oyster...
...or maybe a plant. It would use bark to imitate the wood of the chest, and could snap and secrete a gluey substance like a Venus flytrap.
[Answer]
I like the idea of using hermit crab tenancies with the described "natural state" as being an amorphous blob, (imagine Gastropod such as a giant slug), or perhaps an octopus like body, as the basis for a mimic. As others stated, it could simply obtain a new "shell" as it grew in size. I imagine it breaking apart a container in order to empty it, and then use its adhesive pseudo-pod limbs to collect the pieces into a protective and/or camouflaging shell, much like an octopus collecting coconut shells to hide in.
A large mimic may find a room in a dungeon and take residence there, thus the door mimic. A VERY large mimic might find an abandoned cottage for its shell, becoming the House Hunter.
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[Question]
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When a person dies, their soul doesn't ascend to the afterlife automatically. The soul builds a connection with its body while alive, and remains attached to that body in death. Through natural decomposition, the soul gradually loses its connection to the mortal realm. At some point, when the body decayed enough, the soul ascends to the next life where it will be judged by god. It will either be allowed into heaven or join the reincarnation cycle to be reborn and given another chance.
The ascension of the soul however, is not always guaranteed. While it is trapped in the body after death, the soul is protected from supernatural forces. However, There are invisible predators that prey on and consume vulnerable souls. These are called wraiths, which are angry spirits that have been unable to ascend properly and remain trapped on the mortal realm. These spirits are in constant pain, and seek to take out their agony and misery on the living by killing them. They are also given to consume other lost souls and grow in power. This has been common enough throughout history to be a real concern.
This is why funeral rites and proper burials are held as sacred, because they guaranty passage into the next life. Priests are used to help guaranty the process of ascension. Through performing the necessary funeral rites and given the deceased a proper burial, they protect the soul while it remains in the body from malignant forces. These are rites only chosen priests can perform, which involve complex magical rituals that are learned through years of study. This has given the church a strong presence, and has made them a powerful force in humanity. Religion and faith play an important role in daily life of people, and priests are held in high regard in their community. Otherwise interfering with a body (cremation, dismemberment, etc) is considered a great crime. If a body doesn't decay naturally, the soul may become more vulnerable.
Individuals who go off to war are given a special place in society. Warriors are given markings, or runes, by priests that are akin to magic tatoos. If they die in war, their souls ascend automatically without delay, so they can go into battle without fear. Being a soldier is a high honor, as is dying in war for your nation. I want to keep these special runes limited to soldiers so that only they can be given them. There needs to be a good reason for priests to not simply give them to everyone. What would be a non-malicious way to justify this?
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The rune binds the armor and weapons of the wearer to their soul. When they die, their soul appears with their combat gear. They can then use those arms to fend off the wraiths and fight their way into the next life by themselves.
But this does not just requires that the person dies while carrying their weapons, but also that they know how to use them properly. Combat between souls and wraiths works just like combat between living people, so their combat training will help them. An untrained civilian would not stand a chance against the wraiths. The best sword won't help you when you wave it around like a feather duster. That would make the runes useless for civilians.
But the runes would still be useful for any skilled fighter who is not technically a soldier: Law enforcement, gladiators, violent criminals, duelists, bodyguards, civil fencing instructors. But those really don't *need* the runes, because they will most likely die in an urban environment where a priest can take care of their soul (criminals might be an exception when the punishment for very serious crimes is execution without burial rites, which was sometimes customary in the middle ages).
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Because the runes only work when one dies in battle. Possible explanations for this:
* Minutes before death, the rune must be charged by the wearer's rage, or it won't activate (Negative side-effect: they might also work on people who just happen to be very angry before dying. Positive side-effect: they would only work on *true* warriors who have the right mindset. No Valhalla for crybabies).
* The runes only work when a lot of people die in the same area within a short timespan, like it happens on a battlefield (side-effect: they would also work in case of a large-scale disaster)
* The rune only works when the wearer kills another person the day they die. A civilian would then never wear such a rune, because it means they are potential murderers. This might also raise the ethical question about why killing is socially acceptable when it happens in war. (side-effect: only works on warriors who are skilled enough to score at least one kill before biting the dust themselves. That might be a good motivator, though... or a reason to back-stab a comrade)
Another option might be that the rune works exactly like a proper burial, but is way more expensive and way less personal. So doing the burial rites is usually the preferred way of getting someone to heaven for both sentimental and financial reasons. But when one dies on a battlefield, it is unlikely that they will get the proper burial in time. But warriors are regarded too highly to allow that to happen to their souls. So they get the runes as a contingency measure.
But this might also make the runes popular with anyone who has moderate wealth and a profession where there is a high risk of sudden death without anyone finding their body. For example:
* Hunters (who *could* be considered *kind of* warriors, even though they only kill animals. Cultures who idolized soldiers often attributed similar virtues to hunters)
* Anyone who travels a lot (who might carry a weapon and learn how to use it to defend themselves against street robbers. So they *might* qualify as warriors)
* Sailors, who are constantly at risk of falling over board and drowning in the open sea (but when there is a lot of piracy in your world, then sailors might also be trained warriors who see even more combat than foot soldiers do).
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Runes mark warriors for life. In any conflict, opposing armies will hunt down warriors and kill them, because they will represent the greatest threat. Other castes do not generally participate in conflict and are required to maintain the normal infrastructure of the country - it is in the interest of conquering armies to leave them alone.
Even in ordinary crimes of violence, warriors will be seen as a threat to criminals and will also be summarily killed. They are a threat, because they have to be assumed to not only be able to, but highly likely to, retaliate and to do so most effectively.
Warriors expect to die in battle, anyway, and with the protection of their runes they are most likely to make the most of any opportunity to do so. Civilians do not share this view - they will work hard to earn the money to pay for their burial rites, but do not want to hurry them.
Runes, therefore, are not an advantage to other castes.
This assumes that runes are only effective when applied to a healthy living body before battle, and are non-effective when applied to the dead or dying, but that does not seem to me to be an unreasonable assumption from the OP.
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The rune is only applied before a battle, and when activated drives the enchanted warrior into **a berserk rage.**
Of course, it can be applied to *anyone*, but after that you'll have a mad bar-brawler loose in the middle of the city.
Oh, and it's a **permanent** rune. The enchanted one might not be expected to come back to society. Those who did suffer from societal exile because their uncontrolled rage. A bit sad though.
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**Why the soldiers won't just refuse the rune and battle normally?**
**Viking-like** society, like described by OP. Warrriors want to die in battle, as brave as possible, so they can have more chance to be judged, and let in to heaven (Valhalla). With the enchanted rune, they are able to fight in equal to 5 warrior, so it's not uncommon to send 100 enchanted warriors to fight 300 warriors.
This way, they maximize their chance to enter Valhalla (even though they don't know whether the gods like how they throwing their lives away), and reduce the *potential* death (certain death for 90 people and potentially 10 others, as opposed to 300 potential deaths if you send 300 warriors).
If the enchantment is known from the beginning, **they might develop the culture to this,** so no one actually questioning the practice, and the belief is already instilled to the children mind to follow their late fathers lead.
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>
> There needs to be a good reason for priests to not simply give them to everyone. What would be a non-malicious way to justify this?
>
>
>
You already know that there are problems with your premise, and that's why you are asking the question.
But there are more than adequate answers within your premise.
**Anyone can ascend, though souls are at risk.** Given the proper burial, anyone can ascend. So while runes ON a person are valued, proper burial and such will be much more valued for the common folk.
**It is difficult in war to bury people properly.** Given the risk of not getting a proper burial, particularly if you are on the losing side, it may well be that the runes were absolutely necessary to sweeten the deal for any warriors. It's actually not unreasonable to not give runes out to everyone, as everyone else is more likely to get the proper rites.
So, why not give the runes to everyone?
* **Resources.** It costs something for the priests to do, in energy and
time. Governments and rulers give money to the priests to fund this extra effort. It would not be surprising if all of the ruling class would automatically be considered warriors, even if they aren't technically. For those in power there is always a loophole.
* **Culture** As others here have pointed out, if the culture is behind it, the consequences for a priest giving out an unwarranted rune should be dire--by law or custom. Fighters are more valued by this society, so they get runes.
* **Because it guarantees an afterlife to those who might not be buried, or who might be defiled by the other side** See my point above.
* **As a recruitment tool for conscription** Others have talked about it only activating in battle, but, I think that having it be a permanent effect is a great way for lords to recruit. No matter how poor you are, even if you can't afford the best rites, the fact that you served in battle would protect you, even if you survive and die in your bed at the ripe old age of 80.
* **As a way to track & punish your men** So the flip side to it always being on--deserters. The runes may do more than just help the soul move on--they might also be unique or fairly unique, and a way to track those who have left. Punishment is the removal of the runes. And you might actually have an entire group whose job it is to track down deserters, bringing them back ALIVE, so that the runes can be removed, possibly a prison sentence, and public humiliation. If you dishonor your nation, a dishonorable discharge includes removal of the rune. Runes are placed on a highly visible area such as the face, and if they are removed, that too is visible. (There's lots of story stuff to mine from this, and you could even have an underground tattoo artist that tattoos the area, maybe putting in a fake rune, or covering the area. Such an artist would be shunned by society, of course.) With this in place, very few would desert and most would rather die or commit suicide than dishonor or desert. (Alternatively, you can remove them remotely through magic, after a military trial, no need to capture them).
* **Never leave a man behind** This is the positive side of tracking. If a rune marked is alive, the record of their runing glows. And you could have a compass that points toward the living who are marked. It could let you know to find them on the battlefield and treat them medically, or that they are captured. The loyalty cuts both ways. This society values their warriors, so if possible they never leave a man behind.
Now, you might think my reason of **track and punish** sounds malicious. But I don't think it is. You get marked, you pay the price in loyalty, as it should be. In this society, that would not seem malicious--it would be just and right. And even if it is malicious, it's not malicious towards someone who has never been marked.
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## priests
If the priest caste is required to create the runes (and drive he rituals that power these runes), then they will be doing so because of the gods. If the gods decree that only warriors get the "go directly to heaven, do not pass Go, do not.." treatment, then the priests will know this better than anyone.
Priesthoods tend to be the source of long-standing traditions and religious laws. They have a vested (pun intended) interest in maintaining that status quo.
## the gods
If your gods are the power source for these rituals, then the gods themselves can define punishment(s) for those who break the law.
* the runes simply don't work if placed on a non-warrior (because the gods know...)
* the gods curse the non-warrior and/or the priest with disease, a disability of some sort, and/or a painful death
* perhaps they are cursed to become wraiths by committing such heresies!
## society
In addition, society itself may help enforce such rules. If a rich noble is seen sporting a rune he purchased illegally, it's possible the noble will be killed on the spot by a mob of angry peasants who fear the gods' retribution for such a sacrilege. (Though this begs the question of what happens to retired warriors...) Overzealous mobs have been known to do worse for lesser reasons throughout history.
## other warriors
Perhaps other warriors consider it a sacred duty to carry out divine retribution against any who would dare commit such a sacrilege. They might first desecrate the rune (ouch!), then see that they suffer and die somewhere far away from the priesthood, ensuring that they never receive proper burial. This, then, dooms them to either becoming wraiths themselves or becoming a tasty snack for other wraiths.
And then perhaps they go after the priest who created it, too...
## the rune
It is possible (depending on how you define your runes) that the rune is not the exact same artwork for everyone. Not just a "Everyone gets stamped with the same swirly pattern," but a unique mark. If that mark is unique for each *priest who creates it* then there's a signature of who did the deed.
That signature can then be traced back to the priest. And that priest can be killed, defrocked, excommunicated, disfigured, etc., for the crime of creating it illegally. This is a built-in incentive to not get caught.
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The first thing that comes to mind is that the runes only work if the wearer dies in battle. They require some degree of passion and pain to activate that can only be achieved in combat. You could give them out to farmers and weavers and whoever else but when they died of old age or natural causes it would serve no use.
Another option would be to say that the rune causes side effects. The most obvious one to limit it to warriors would be a kind of berserk state. So the runes are only applied just before battle and the application of the rune drives the warriors into an uncontrollable frenzy. The downside to this is what happens to the surviving warriors, but you could just say that the runes effects wear off after a while. It also could be applied to people who are dying as the berserk side effect wouldn't be such an issue then, which is not what you want.
Finally you could say the runes are fuelled by the blood of your enemies. Only through killing others can you activate it. Similarly to the first option this means that the runes are only ever useful in a combat situation.
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**Built the culture that warrior honor their opponents**
**Culture:**
* go to afterlife is a common goal of society (both side at war believe so)
* Warrior fight for honor
**How the rune work:**
* The rune need to be active by someone else on the battlefield. Allies or enemy. But prefer by enemy.
* Murder = no honor = no afterlife
**Example:**
[Speaker for the dead](http://Speaker%20for%20the%20Dead)
(From [wiki](http://enderverse.wikia.com/wiki/Pequeninos))=> When a Brother was considered wise, or had achieved something great, they were to be sent to the Third Life by his greatest friend or his greatest enemy.
You can compare your 'afterlife' definition with 'Third life' in [Speaker for the dead](http://Speaker%20for%20the%20Dead) to get some idea.
More resource about 'Third life' <https://www.shmoop.com/speaker-for-the-dead/third-life-symbol.html>
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I think the most natural way would be to limit the priests‘ ability to apply the rune (as already suggested by Erin T), while creating a good reason for them to do it for warriors.
The first part can be accomplished if the application of the rune costs a lot of mana/life force/time/or requires constant maintenance, so that each priest can only tend to a single warrior at a time. My favourite idea would be that keeping the rune active is extremely physically taxing for the priests. Priests have kept everything about it secret. But their true reason for only giving it to the warriors is that warriors rarely live long. If you give the rune to a young merchant, you might have to tend it until you are 70 years old. In the worst case he might outlive you and the rune will keep feeding of your corpse, dooming your own soul!
The second part can be accomplished via connection between the castes. A historically motivated idea would be that the warrior cast holds de facto power „by divine will“. They need the priests to perpetuate that belief and the priests are obviously motivated to cooperate with the top. The tattoos might be the defining characteristic of the warrior class. Obviously they would punish any transgression.
An other idea to motivate the priests to make an exception would be a hostile environment, where the priests depend upon the protection of the warrior caste.
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I have a world where remnants of [advanced ancient humans](http://tvtropes.org/pmwiki/pmwiki.php/Main/AdvancedAncientHumans) (tv tropes link) live among us, but we are not aware of them.
Is there some problem that people with mathematics more advanced then ours would be able to solve easily but we could only check the correctness of the solution, either by hand or using computers?
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Yes, they could break the [RSA encryption](https://simple.wikipedia.org/wiki/RSA_(algorithm)) algorithm.
RSA encryption consists of encoding a message using the product of two very large primes, a little easy (known to us) mathematical work with this number produces two keys; which we call the public key and the private key.
The public key can be published and known to everybody. It is **not** a secret; it is intended to be known. Transmit it over the Internet, put it on a billboard, whatever.
With a very straightforward algorithm the public key can be used to encrypt a message. However, the cool part of RSA is that this encrypted message, even with the public key known, can only be **decrypted** with the private key.
RSA encryption is used everywhere, on the Internet, in banking to move trillions of dollars around the world.
However, it relies on a mathematical difficulty that, so far, we do not know how to solve: Factoring a very large number into component primes. Current estimates are that it would take millions of desktop computers working together millions of years to factor numbers as large as those we use in RSA, using the best factoring algorithms known to man.
Even if we had quantum computers with enough q-bits to factor this number, those algorithms would still take thousands of years to discover the private key based on the public key. On top of that, we can just increase the size of the numbers. The 256-bit, 512-bit, 1024-bit encryptions you hear about are just how many bits are used to store an RSA key, in those flavors. There is no limit to this, and every time the number of bits is doubled the number of breaking calculations grows exponentially. So if some compute algorithm breaks 1024-bit encryption in a day, in 30 minutes I can have a 2048-bit encryption it cannot break in hundred years. (I am a mathematician familiar with this algorithm).
If you could **break** the factoring problem using some sort of mathematics or quantum computing algorithm currently *unknown* to us; to the point of knowing within a day both the public and private key no matter how long the encryption, then you could trick nearly every major bank in the world into transferring billions of dollars into your accounts, you could break security on nearly every supposedly secure website (including that of many government computers, most brokerages and stock market exchanges). You could utterly destroy commerce and the economy. You could hack elections, and law enforcement records, and the military command structure, anything that is recorded, transmitted or received online.
I am not privy to what organizations like the CIA and other secret agencies with billion dollar budgets may use for encryption; so it is possible they **do not** use RSA, or use it with some other layers of encryption we cannot break mathematically. That said, what common corporations, banks, websites, and government agencies use is always some flavor of RSA relying on the *apparently intractable* mathematical difficulty of factoring very large numbers.
P.S. Forgot the other requirement: We can ***check*** whether a factorization is correct by simple multiplication; done in a few milliseconds at most on a regular desktop computer, and even able to be done by hand within a day, given some large paper to work with 1000 digit numbers.
### Correction due to commentary
My claim above about whether quantum computers could break RSA is mistaken; but it can be excised without changing my answer. First, no quantum computer in existence has thousands of q-bits in order to do that; they have not factored numbers of more than about sixteen bits. Second, the question is about ancient human **advanced mathematics**, not advanced *technology,* and for our foreseeable future breaking the RSA factorization problem would definitely be in the realm of an advanced *mathematical* technique, not a *technological* feat.
**An aside:** In the [timeline of quantum computing](https://en.wikipedia.org/wiki/Timeline_of_quantum_computing) there is no shortage of hype; the most plausible recent advancement is IBM's 2017 claim of a 17 qubit computer. D-Wave claims 2000 qubits, but [Their own announcement](https://www.dwavesys.com/press-releases/d-wave%c2%a0announces%c2%a0d-wave-2000q-quantum-computer-and-first-system-order) says their system operates "1000 to 10,000 times faster" than classical computers. They cannot be all entangled with each other then, and 10,000 times faster is not enough to challenge RSA; we could just make the key longer to compensate, or change our keys every week, or for critical applications like banking or national security, every day. There is no shortage of big numbers!
I repeat, this is a side issue, and no known quantum hardware is anywhere near enough to challenge the security of RSA. But advanced mathematics plausibly could do so.
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There are quite a few such problems. However, there's a nasty trap for an author in using something like this. If you aren't sufficiently comfortable with advanced mathematics to describe a mathematical problem clearly, you may well make mistakes in using it in your story. Such mistakes are vastly amusing to people who do understand the problem.
The kind of situation you're describing is reflected in the [P vs. NP question](https://en.wikipedia.org/wiki/P_versus_NP_problem). This considers the difficulty of verifying answers to questions, as opposed to finding answers to questions. There are problems whose answers can be verified easily and quickly, but which have no known algorithm for *finding* an answer quickly. Problems whose answers can be found quickly are in class **P**, and problems where an answer can be verified quickly are in class **NP**.
The question is if **P** = **NP**? Currently, we don't know either way. It seems likely that **P** and **NP** are not the same, but we can't prove it. A proof that they are different would be a convincing demonstration of highly advanced mathematics; a proof that they are the same would have vast implications for philosophy, mathematics, computing and many other fields.
However, it's a bit of a difficult problem to get over clearly. A better idea for story purposes would be a method of generating [prime numbers](https://en.wikipedia.org/wiki/Prime_number), or an explanation of their distribution among the numbers (which amounts to much the same thing). Prime numbers are fairly easy to understand, as whole numbers that aren't divisible by any other whole number (except 1), and many people already understand them.
Mathematicians have sought to understand them for thousands of years, but we still have no simple formula or algorithm which will generate all the prime numbers. Your readers can understand the problem, and your characters can check the primality of large numbers easily enough with a computer.
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This used to be a comment, now it isn't anymore.
There are a number of things, but most of them are hard to do in a book (and such). Take for example generating new prime numbers - well, you do not have those prime numbers, so what do you write instead? You could make up something, but I personally think it is unsatisfactory. On top of that, prime numbers in particular are a bit cliche.
I would choose a different approach: Predicting the outcome of experiments way more accurate than we are able to. I will give you two examples later, but let us first discuss why I think it is a good idea:
1) We can very easily verify the prediction
2) Their advanced knowledge is not just reflected in one problem but several problems they would have to solve at once
3) Someone that is maybe even unknown to the community will not just go ahead and solve those problems way better than we currently can (see 2)). If they have a formula for prime numbers, well, anyone could've come up with that (not really, but kind of). It would be a very good indicator that we indeed have more advanced people.
4) You can make up everything yourself (my two examples) or take the numbers from existing experiments.
So, let's see my examples:
a) Predicting the weather accurately.
Very easy to verify. They tell you: It is gonna be raining X much over 10 minutes in Y at Z o'clock tomorrow.
In order to do this, they would need way more efficient algorithms than we do and a lot more knowledge to gather that kind of information from the data available to them. This is such a complex problem that demands so much knowledge that it could only be done by such people.
b) Predicting where exoplanets are going to be before they are "discovered" by telescopes.
I want to do this one because it shows how easily you can come up with something that might even be relevant to your story. I don't know your story, but let's assume it was about space colonization for some reason. This would demand very, very advanced people, but in principal it is the same as a) again. They would need very efficient algorithms + an extensive knowledge.
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There are many problems in *physics* being actually mathematical problems. For example, [string theory has shown roughly $10^{500}$ vacua](https://en.wikipedia.org/wiki/String_theory_landscape) ($\approx 10^{500}$ possible Universe), but there is no way to find, in which we are. It leads to the [NP-complete](https://en.wikipedia.org/wiki/NP-completeness) [Knapsack-Problem](https://en.wikipedia.org/wiki/Knapsack_problem).
Solving them could lead to major advances in engineering (artifical gravity and so on).
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Human's primary sense is sight. Therefore our maps include icons designed to represent various sights.
**Scale maps** include reference scales and accurately represent to the distance between the visual icons.
Scale / literal map
**Symbolic maps** (such as subway maps) present import landmarks and relative positions between them.
Subway / symbolic map
But *always* we use sight and symbols to represent what we see.
1. How would we make map for creatures that use scent as their
primary sense?
2. How might such a (for example) "smell map" "appear"?
3. How would we create a scent map?
Bonus points for guesses on how this might affect their cultures.
Bonus points for information about how other senses (sound, taste, touch) might be done.
PS: Thanks to The Wandering Coder (see comments), here's what a Braille map looks like
Braille / touch map
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I doubt that a scent map could be accurate enough, for long enough, to be viable.
Think about it, most scents are somewhat impermanent: the flora will change seasonally, scent patterns will change dramatically with even a slight breeze, not to mention that even on a temporary map everything would be represented by an amorphous gradient.
Represented visually a scent map might look something like this:
Even if you could some how fix certain scents to certain areas, how would you differentiate things that generate the same or similar scents, say this group of pine trees from that group of pine trees?
Species that use scent as a primary sense often use more of a Hansel and Gretel method, basically they leave bread crumbs or scent trails. A dog probably finds his way home by marking his path along the way. Similarly ants leave pheromone trails. Predators usually mark territory, but even then these markings are temporary and change constantly with the animals day to day movements.
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An animal that has poor/nonexistent vision would still understand spacial relationships, so it would be a "map" as we understand it.
It would record points of interest and features, not *just* what they smell like but what they *are*. When we see a "river" on a map it is not a picture of water, and a waterway may look any number of ways. We recognize a waterway when we sense it, and the map is symbolic and abstracted.
Maps for some purposes may provide information on recognizing specific sensory input: *street view* is handy so you can spot the building rather than looking for an address marker somewhere. But it is not the main substance of the map and not necessarily present at all.
A map may be like the braille example, read by touch which is more localized and fine resolution. That makes me think that such a race would develop a touch-based writing system, too, making the example complete.
But suppose that the writing system does involve scent, or the people are pre-literate. A map *key* may use patches of scent and correlate with abstract symbols, or be attached by strings to the position being documented, if it needs to be larer and more isolated than the map's scale would allow.
A supplementary page may have a *name* as a characteristic scent or a cartoon of idealized scents that will make sense to such a being as a way to then recognize that place.
A *linear map* of a river or trail might be a roll of material (think a very narrow scroll) with tactile marks and scents along its length mimicking the characteristic or unique scents to be found.
Again, a "cartoon" rather than exact copy could be used: "a (specific) type of marshland with these kinds of vegetation" can be impressed, without the smell being actually the same.
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I very much doubt that a animal that cant see a map would be able to make one. There are far more efficient ways of navigation for a animal that relies on smell.
A map that relies on smell would have too many similar areas of overlapping smell, none of which would be particularly unique. like this:
This would be hard to understand. though it may be useful to record the fauna, faunas and geology in a certain area.
Instead of a physical piece of paper, for navigation I'd suggest particularly strong smelling markers that cover a large area should link up in paths along the country. Then the member of the species traveling is given lightly scented sticks in a order that match the scents of the markers on there path. There would also be smells that they are taught to stay away from. I guess you could do the same thing with a map but the markers are an important part of the navigation method or it would not be clear enough to read.
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We already put non-visual information on maps. I can look at a map of a place and know how to reproduce the noises used to indicate those places.
The answer for your alien species is the same: **writing**.
Writing lets you encode any of your senses in a different medium. We humans use mostly visual writing, but we also have several tactile writing systems. If you consider other ways we record information in physical objects, we also use variation in magnetic fields, which an alien species might be able to read.
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We have a real-world examples of maps build on other senses: [the waggle dance of bees](https://en.wikipedia.org/wiki/Waggle_dance). This is very interesting, but it boils down to a relative description of points of interest. With the colony as starting point it indicates direction and distance to the POI. With this way of information coding we could utilize a lot of senses to transport this informations.
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The maps we make use several kinds of coding - shapes, colors, written language (letters), symbolism. A scent-primary map would likely need several layers as well, to separate the kinds of information being offered... and as I'm not sure how exactly scent as a medium can be differentiated as much as color and shape are visually (although maybe different base scents or top notes can be used as symbols, those with *this* type of mean variations of X, or *that* type mean in the Y ranges), I will assume that while scent is primary, a secondary sense is allowed. Touch is a good medium, since we have maps with tactile information - braille maps, and also globes where topographic information was included as [raised bumps and dips](http://www.worldmapsonline.com/raisedreliefmaps.htm). I think this kind of topographically differentiated map is a good starting point - it lets us get the shape of the environment pretty intuitively, and also lets us use shapes to convey symbolic information.
There are ways to store scent information for later - scratch and sniff stickers or paint is an easy example. There are ways to separate scents into a palette, basic scents [building to more complicated ones](http://www.scentgourmand.com/perfume-vocabulary/), to talk about them, recreate them, and so on. This is not often used in casual conversation, since it is primarily of interest to the [scent industry](http://www.kafkaesqueblog.com/2013/01/30/a-beginners-guide-to-perfume-how-to-train-your-nose-learn-your-perfume-profile-more/), but it gives background for how complicated scent can be, and ways to layer and combine them, or pick them apart.
After all of that, we take our scented paint (in a very wide variety of basic scent components) - and practice that artistic technique known as [pointilism.](http://www.creativebloq.com/graphic-design/pointillism-examples-dot-art-11121135) Clever, precise little dabs all working together to create a larger picture. In this case, the different scents, notes, and layers contained in our wide palette of paints. Some base scent that's vegetal and plantlike, can be dabbed here or there with a sharper note to make 'pine', there with a mellower one to make 'moss' (or the reverse, I know it can be done, but I'm not trained).
General climate, topology, ecosystems, can be painted in this fashion either realistically or symbolically (that is, either "pines and oaks" or kinda forest-like or desert-like), as different shadings of color are used on topographic maps. For artificial structures, some symbolism will be needed, certain textures or shapes to mark paths, buildings, residences, towns and cities. But the scents can be layered to give further information - symbolically on a large scale, perhaps paper and ink scents to indicate administration, while a bread scent might mean a restaurant or grocery, as the legends on our maps use little color-blocks. Alternatively, the scents can be used very specifically on a local scale map - here is the bakery with the scent next to and overlapping the oak grove, there is the spice shop, mingling scents with the paper mill.
If the primary sense is scent, then they will be very good at distinguishing such scents - what we use as scratch and sniff paint might be perfectly legible to them even 'inactivated', or might be gently activated - brushing a hand over the map to activate the whole thing at once would give better legibility like we would get from moving to better light. The scents would wear off after a while, they are volatile, but probably not immensely more so than paper maps which fade, or get worn and tear, or just get lost. And they probably *can* distinguish both the fine distinction of the little dabs of coexisting or mingling scents from the scent-paint, and the overall spatial relation between the areas as the scent changes over the whole map, as well as we distinguish fine color shading or details.
We can use smaller visual maps because we have skill at distinguishing those details, those who use scent maps would have as much skill in their respective specialization - but for us, it might make sense to imagine the map is resized for our noses (as Braille ones are resized for our fingertips), so we can tell things apart. Maybe a poster sized map, where we can physically sweep over it with fingertips and noses to experience this area with these textures and scents is forest and those textures are grasslands, that area with those shapes and layers is city, there is the sharply contained and contrasting scents from buildings used for industry, here are each cuisine's scents from a restaurant area blending and overlapping along that street.
As for scents changing throughout the year, they would probably plan around it - either by using scents that don't change as much for primary identifiers, separating temporary form typical scents - or using them more symbolically. We don't get lost at the greenery on the map when autumn comes and the forest is orange, or snow falls and the streets are white, because we know what the map means and how the land should change.
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Pretty much every vehicle ever invented has been used for racing on at some point, so it seems likely that people would want to do the same in space.
However in space it doesn't really work the same way, the main problems being:
1. There is no real sense of speed. Can you even get the same thrill out of a race without the ground rushing past beneath you?
2. Collisions would be incredibly dangerous.
3. Everything is constantly moving as things orbit each other so the track is changing all the time.
4. The exhaust trails (or any dropped objects) from one racer could interfere with the other racers.
Given all these constraints, and possibly more, would it be conceivable to have races in space and if it was conceivable what form would those races take?
Tech level: No FTL, highly efficient reaction drives and radiation shielding. Multiple planets settled, along with space station and asteroid/ring mining stations. Essentially we have decent space tech but everything working within our known physics limitations. No warp drives or force shields.
My first thought is that something like the [round-the-world sailing race](https://www.clipperroundtheworld.com/) might be a good model but I'm open to other suggestions.
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Depending on the type of race you want, an around-the-world sailing race could be a good start. However, I propose you look in a different direction: [air racing](http://en.wikipedia.org/wiki/Air_racing). I'm thinking particularly of races with pylons or gates, like [Red Bull's](http://en.wikipedia.org/wiki/Red_Bull_Air_Race_World_Championship). In these races, pilots have to follow a specified path through a series of obstacles.
Using this as a model addresses all of your concerns.
1. The course is (relatively) small, and the gates and any monitoring equipment provide visual points of reference so pilots can "feel" their speed. Also, they involve a lot of turning and maneuvering, so the pilots will feel the g-forces.
2. Collisions are still potentially very dangerous, as they are with aircraft. However, there are a number of safety considerations. First of all, the pylons and gates used in current races are inflatable, so hitting one does not present a significant hazard to craft or pilot. Also, races are usually run as time trials, not concurrent competitions, so there is no risk of racers hitting each other.
3. The courses are temporary. They are set up before a competition, left in place for the duration (usually a weekend), and taken down after. Their configuration may be gravitationally unstable, but it should be able to be maintained for such a short time with minimal correction, especially if they are a low-density collapsible material, as implied by point #2. Smaller courses could be placed in planetary orbit, with larger ones in solar orbit, maybe in the asteroid belt.
4. As mentioned above, the racers fly the course at different times. This gives the possibility of maintenance in between trials, such as correcting gate positions or, if necessary, clearing debris.
There is a lot of possible variety with this type of race. There would be different classes for different types of spacecraft, with various restrictions on their capabilities. Different events would have different course lengths and layouts, and they wouldn't need to be strictly agility courses. I could imagine, for example, racing between moons of Jupiter with small intermediary agility sections. All in all, if you're looking for thrills and a feeling of speed, I think this is the way to go.
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Unfortunately there are some tough problems with space racing:
1. **Speed:** In space, you move fast--*really* fast, literally faster than a speeding bullet. However, space is bigger than you are fast, which would make races seem slow. An interplanetary 'racetrack' would take months or years per lap. Even the smallest possible 'racetrack,' low Earth orbit, takes around 90 minutes per lap. This brings me to the next point:
2. **Skill:** We like to make racing about the skill of the pilot, not an engineering challenge. Formula 1 places ever-stricter limits on 'driver aids' every year and NASCAR basically specs out the entire car for you. However, maneuvering in space is very difficult without computer assistance. Either the pilots would be passengers simply operating the computer, or they would have to be maths professors. Even so, their speed around an 'orbital racetrack' is determined purely by the physics of the situation: achieving minimum time is basically an optimization exercise for the trajectory designers, and everybody would probably come up with the same plan.
3. **Money:** Space is expensive. Even NASA's low-cost, high-risk missions (the Discovery program, or class D missions) cost hundreds of millions of dollars, more than any F1 team spends in an entire season. Plus a space race would not be all that exciting (to the average viewer): long periods of nothing punctuated by short periods of computer-controlled burns. By the way, this is all impossible to film without the networks developing their own rockets, at similar cost. Not only would nobody want to compete, nobody would be willing to cough up the money to host.
Basically, space navigation is too far outside the human scale of experience to be good competition for humans. Instead I would suggest zero-g or low-g sports for humans to play in space.
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# It is all about the size\*
\*no that is **not** what she said.
As space travel happens all relative to gravitational sources, travelling from A to B in space can be achieved by something as fancy as a 2-story-house and a bunch of fire extinguishers.
Or by a highly specialized racing ship with huge fusion drives and fancy radiator fins to get read of the heat before it cooks the pilot(s).
Although no matter which of both representations fits your racing ships better, they still end up having to traverse huge distances while being in motion themselves.
## So how would you lay out a race track in space?
### Around the World
As you already mentioned, there is the *around the world* format where you set certain checkpoints which must be reached sequentially. This could be achieved by placing these checkpoints in stationary orbits around a planet and have the racers pass each of them.
Which would end up in a contest of navigational computers, the more money you got the better your racing skill. **Alas** you could counteract this by introducing certain rules to racing, e.g. no computer assistance, which would mean physicists would become the best racers - or every racer becomes a physicist.
Now, described above is an *easy* racing track, as every checkpoint is static relative to other checkpoints.
If you wanted to spice the whole thing up a little (and introduce some nasty headaches) you could put checkpoint at different orbital planes around a gravity source, effectively making them move.
### Around the 'Verse
It's space, and there is literally a lot of it. So why not make them race from system to system, making certain planets or space stations checkpoints? In the end you'd still end up with most of the racing being navigation and controlled translation burns. But that's how it works.
## How would *racing* work?
Now as you will know, the faster an object is going, the less time it takes for it to move from point A to point B. In space these distances and the speeds involved to travel between these distance are a multiple of those on earth. Also there is no friction in space, which means the only reliable break system is to rely on getting caught in the gravity well of a small object (e.g. passing near a planet in order to have it's gravity pull you off course - the base assumption underlying [gravity slingshot maneuvers](http://en.wikipedia.org/wiki/Gravity_assist)) **and** [retro burning](http://en.wikipedia.org/wiki/Retrorocket), essentially the practice of decelerating by firing your thrusters against your current direction of motion.
Making the fear and thrill of overshooting your target by millions of kilometers the most exciting thing in the process of racing.
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There's a short story whose name I can't remember that I read many years ago that took a very different approach to space racing. It was basically the Tour de France in Earth orbit. Crazy as this might seem it would be possible if there were enough satellites so the delta-v requirements per leg were low enough.
They used pedal-powered spacecraft--the pedals provided the power that ran an ion engine that actually moved the contestant.
I rather suspect the available delta-v is a lot less than the author was picturing, though.
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An orbital race would be mostly thrusting towards the planet to stay in a low orbit as possible while exceeding the normal orbital speed at that altitude. This is not really interesting. Unless a thruster fails and they shoot off into space...
An interplanetary race would depend on how daring the pilots are and would take several months.
The result will depend on the delta-V of the craft and the accuracy of the nav computer
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Arthur C. Clarke wrote a story "Sunjammer" or "The Wind from the Sun" where ships sailed from the Earth orbit to the Moon using sails driven by solar wind.
No fuel, thrust, or crazy high turning needed.
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I once imagined a "yacht racing league" wherein contestants in their little specialized ships plunged toward the sun, then at the last minute ("minute" being somewhat relative, depending on how razor-edged they were being) deployed a solar sail to catch the solar wind and shoot back to a higher orbit.
Elements of the race would include mass of your ship, size of your sail, your ability to pick a good area of the chaotic surface of the sun to aim for when deploying your sail; catch a good flare, you're literally off to the races. This brings in the need for good shielding, which raises the mass of the ship, which necessitates an increased sail size... Another element would be the mettle of the pilot.
I never bothered to work out the physics of whether or not this sort of race was *possible*, but it could make an interesting action film, where physics are overlooked in favor of ***"OMG, did you see that???"***
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I doubt this will ever be seen, being such an old thread...but I had an idea recently, and this thread came up during an intellectually curious search.
Space racing could be done really soon, in my opinion, using the same basic theme as FPV drones. Pilots would be on Earth, and have nice equipment which would point to space. A course would be launched into geosynchronous orbit, unfold, and carry with it a number of drones; these drones would work like the the CO2 drone on the ISS, or perhaps you could imagine one of the little balls Luke Skywalker practices with.
Pilots would battle latency and signal noise to race around the unfolded track. Damage wouldn't be a problem because of the size of the drones, and speed would be fairly slow since everything is in orbit together. The biggest problem would be flinging off into space after bouncing off an obstacle or another drone.
The whole thing would be like a 6dof space game, using FPV just like drones. I have a custom controller that I think works well- it has two thumbsticks and two trigger-finger sticks, a total of four joysticks, allowing me to have all 6 degrees of freedom on joysticks. I practice "orbital racer" and "starmade", two games which accept vjoy and allow me to practice space FPV.
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Perhaps the thrill could come from massive G-forces instead. The racing course could require the pilots to do sharp turns and rapidly accelerate and de-accelerate to get more points. Also, from KSmarts's answer, instead of inflatable pylons or gates why not use a holographic ones which use a small projector, Or the gates/pylons could be a virtual ones produced by the pilots HUD.
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Laser point defense is a known concept.
A powerful laser beam, either continuous or pulsed is used to shoot down or deflect either a projectile or object out of the sky. The concept has been speculated to be very beneficial to a multitude of systems. Vehicles, artillery, base protection etc. etc.
One idea I've seen floating around is the idea of miniaturizing such a concept down to where an infantry soldier can have on mounted onto their person to intercept bullets and shrapnel.
While the idea is interesting, and suggested in place of your typical sci-fi energy barrier-type shielding. It has always sounded a bit...off to me.
First off, would the sensors be able to detect and respond in time? Computers today certainly have the speed and power, but would the detectors be able to sense the projectile in the heat of combat?
And how far out does this system have to be to actually work? Too close and the laser may not be able to do its job.
Additionally, the chances of the laser emitter (which is presumably a form of orb with a lens on the front and mounted on a swivel) missing are uncomfortably high.
These and many more issues brings me to ask:
**Assuming that the technology and engineering is available, is the concept of a infantry mounted point defense laser for intercepting shrapnel and bullets viable?**
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## Potentially, but a minor frame challenge
Other answers may bring up power-density or computation issues. I have a much simpler one.
Tanks can get away with active protection systems which blow apart incoming shells/missiles/penetrator darts/etc. because the chunks of the incoming projectile simply bounce off the tank's rather durable armor. However, a destroyed bullet still flying at a soldier is much more dangerous to that soldier, proportionately speaking, than a destroyed anti-tank missile still flying at a tank is to that tank.
Dressing the infantry in a suit of powered armor as proportionately durable to bullet fragments as a tank is to missile fragments may solve this. However, this runs into another thing: a laser capable of tracking and destroying an object as small, fast, and durable as a bullet is likely capable of doing the same to the infantry that bullet is aimed at.
In other words: if lasers capable of this exist in-setting, they're probably going to *replace* bullets. Even if the lasers are designed to simply vaporize part of the surface of the bullet to push it off-course, that still implies very high power (i.e. laser output in joules/second) and energy (i.e. joules per kilogram or liter of battery) densities, which means that each soldier can likely carry around weapons far, far more destructive — and harder to stop — than bullets. One of these active protection lasers can assuredly do some unpleasant stuff to a humanoid if it can disrupt a bullet enough to save a humanoid. Now imagine ten strapped together and converging on the same point.
[Here is a hard-science death ray calculator you may enjoy.](http://panoptesv.com/SciFi/LaserDeathRay/DamageFromLaser.php) You will find that it takes either (a) a lot of power or (b) a lot of time for a laser to do damage.
Real life active protection systems are, to simplify things, tiny guns that shoot down incoming missiles whereas their much bigger cousins — tank guns — fire super-fast kinetic energy penetrators active protection systems cannot defend against. The same will likely happen with your lasers (presuming power density/computation issues are solved): a little version for shooting down the occasional chunk of shrapnel, a big version for turning portions of people into rapidly-expanding clouds of hot gas, and a complete inability for the little version to deflect the big version.
This will likely end up resulting in just as much infantry mortality as if they were getting shot with bullets and had no APS.
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# Not even close in the simplest case
I worked in the ballistic missile defense (BMD) field for a while. Lasers are a bad idea for intercepting missiles (despite the US DoD [trying to use lasers](https://nationalinterest.org/blog/buzz/us-military-wants-kill-nuclear-armed-icbms-lasers-50377) to do just that, because it sounds really cool), and they would be a bad idea for bullet and shrapnel interception for some of the same reasons.
The biggest problems are a combination of sensor accuracy and just plain physics.
* A) The footprint of a laser on its target is a tiny dot, a few millimeters in diameter at most.
* B) Lasers do not instantaneously blow holes in things Star Wars style- they have to dwell on the same point on the target for a time to compromise it.
* Therefore, C) the sensor needs to be accurate enough to "see" where the laser dot is on the target (which is moving faster than the speed of sound), and the actuators physically pointing the laser must be precise enough to keep that dot in that exact spot long enough. This is further complicated because missiles and bullets spin around one axis to stabilize their flight; that means you lose line of sight on your dot. Shrapnel spins randomly around *all 3 axes*.
[Radar is the sensor of choice in BMD applications,](https://en.wikipedia.org/wiki/Aegis_Combat_System#Ballistic_Missile_Defense) and it's a good one. But the best that a radar can do, even when it already knows where to look for its target, is tell you that it is somewhere inside the width of the beam (for azimuth and elevation), and that it is at some distance between two pulses (range). That gives you a box that the target can be in, not the XYZ points down to the millimeter where a laser dot should go now. Oh, and this target will be a kilometer away in less than a second. Any sensor system will suffer the same or similar issues.
BMD radars are also fairly stationary. Your infantryman is sprinting, ducking, sliding all over the place, which the physical actuators have to account for.
But assume you have an perfect sensor and a perfect actuation system. If a hostile is firing at you with a (slow) Mach 1 bullet from 50 meters away, you have 0.146 second (50m / 343 m/s) to detect a shot, get a target lock on the bullet, decide if it's a threat, and disintegrate it. It needs to do it about three times as fast for Mach 2.9 NATO 5.56 round.
While you're calculating the number of gigajoules it would take to disintegrate a jacketed lead round and praying I don't switch to steel ammo, I'm going to be pulling out my [semi-auto shotgun](https://en.wikipedia.org/wiki/Benelli_M4) loaded with [tungsten double-ought buckshot](https://www.alibaba.com/product-detail/High-quality18g-cc-tungsten-ball-for_1600618775843.html).
**...but if you can disintegrate a bullet at 50 meters, you should be aiming that laser at the guy shooting you**
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## Use predictive AI to aim your ADS
Other answers are correct. There is no way a laser can wait for someone to pull a trigger and have time to respond by intercepting the bullet, but a much more reasonable expectation would be a system that uses cameras and other sensors positioned around your body that feed into an image recognition AI to predict incoming threats and aim your lasers BEFORE the bullet it fired. If the AI sees someone turning their gun towards you, or a grenade land nearby, it can respond by aiming the lasers to intercept the predicted angle of attack.
This makes all of the concerns regarding how quickly your laser needs to aim or time required to power it up a non-issue because as long as your ADS can out-draw an attacker by reading body language, you have eliminated the time it takes to arm and aim vs when you only start to respond once the shot is fired. So your response time is then reduced to how long it takes a computer system mounted to a high speed camera to respond to the mussel flash which could easily be less than a thousandth of a second. The bullet could still be within inches of the mussel by the time the ADS fires in response. So depending on just how handwavy your laser themselves are, this system could potentially be effective at ranges of just a few meters.
## As for accuracy issues...
There is really no rule saying a future tech society can't make a mini orb laser accurate enough to directly hit the bullet, again, using predictive AI, you should be able to map not just where the bullet is, but where it will be so you can hold your laser on target, but what if you don't want this level of auto-aiming technology in your setting?
As it turns out, you don't actually need to hit a projectile for a laser to be an effective ADS. If you base your lasers on the Boeing Plasma Shield concept, you just need to shoot somewhere in the path of the attack, you don't need actually target the projectile itself.
Instead of firing a single laser to try to burn away the bullet, you could fire a set of lasers that converge in the air between you and the enemy just before he fires creating a mid-air plasma burst. This uses less power than is needed to make a viable laser rifle (which solves internal consistency issues), and less accuracy than is needed to directly intercept a supersonic projectile. The plasma burst can do a wide range of things including blocking enemy lasers, overwhelming enemy sensors, visually blinding the enemy, and/or creating a shockwave that can detonate missiles and deflect shrapnel.
The big drawback here is that it will not be able to stop bullets fired at close quarters, but long-ranged sniper shots (the kind where wind speed needs to be taken into account) can be redirected by enough to miss you if it has to fly through a plasma burst somewhere far enough away from you that the slight change in angle would compound into a major offset.
In this way you can use lasers that may not necessarily make for a good primary weapon, but still able to protect you in battle.
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As [automaton predicted](https://worldbuilding.stackexchange.com/a/250421/21222):
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Let's assume a bullet made of lead and weighting 10 grams. You need to heat it up to 1749 degrees Celsius to vaporize it. Let's assume a starting temperature of 25 C for the bullet. You need to give it 1.3 joules per degree Celsius, so about 2.2 kJ. But you also need 22 J/g for fusion and 860 J/g for vaporisation.
All in all, 11 kJ to handle a bullet. Let's assume the laser is 85% efficient in terms of energy, a performance similar to a typical laser pointer. You'll be spending 13 kJ on a bullet, of which 2 kJ will be dissipated as heat in your equipment. That's enough energy to heat a gram of water by 478 C, so be careful that the wiring does not touch your skin.
Supposing you need the bullet vaporized in 0.1 seconds or it hits you, you're cycling 130 kilowatts in the equipment's bus. And you know, you can convert watts to horsepower. 130 kw is nearly the same as 174 hp.
I have a mid-size crossover SUV. Its curb weight is ~1900 kg and it reaches 100 km/h in a few seconds with a 173 hp engine. I think my car's engine alone weights around 175 kg.
You need a reactor just slightly more powerful than my car's engine to power your laser. It will probably be just as massive as well. And then you will also need to add fuel or batteries, piping and wiring, casing etc.
More realistically, your point defense would be a set of really heavy turrets. This could protect individuals in a closed space they have to defend, but I doubt it would be very mobile.
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In my story world, I was thinking about having glass structures built by a prior civilization to preserve information. The reason the structures would be made of glass would be because the glass the structures are built of are also used as a giant data storage device. Kind of like the glass etching technique they’re trying for storing greater volumes of digital data. The scientists developing this glass-based digital storage are currently saying that one of the pluses of this technology is that it could safely store digital data for thousands of years. Since the civilization that built these structures existed thousands of years before the current events in my story world, I figured glass data storage would be an ideal option for preserving data from this civilization. So what I need to know is whether or not a glass building would be inherently structurally weak and collapse fairly quickly, or if it could be done in a way that would be structurally solid, and could realistically last for thousands of years. So, in other words, could my glass buildings last for thousands of years?
Details:
* I’m thinking that they’ve been up for about 3-5,000 years, I know this is kind of a wide spectrum, but you should probably assume the 5,000 years for a worst case scenario.
* It doesn’t have to be a specific type of glass. Any kind of glass is on the table, so whatever lasts the longest. Spare no expense.
* The buildings are likely pyramid-like. Like ziggurats, or something similar in design.
* Also, this is assuming nobody’s tried to purposefully destroy them, like bomb them, etc. Also assuming nobody’s like accidentally crashed into them, stolen material from them, etc. This is assuming no harm to the buildings from humans (I’m not sure if any humans are even living near these structures). Just natural forces working on the structures.
* The buildings have to still be functional (at least for the most part). Parts of the structures could be missing or damaged, but it should be mostly intact and functional, think like the condition pyramids or ziggurats are in at worst.
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[](https://i.stack.imgur.com/QGTmN.png)
## Yes. The structure isn't too hard, but the data is a bit tricker
We have ancient glassware from Roman and even earlier times. It's in good condition. That cup pictured is the Lycurgus Cup; you can still even admire the artwork on it.
Contrary to popular opinion, glass won't flow over time; the 'flow' that you can see in cathedral windows is an artifact of the pouring during the manufacturing process.
So yes, glass will last, and it will probably not even need to be fancy glass.
You may need some base isolators or at least a good mechanical design that allows some movement; glass will HATE earthquakes. Still, the pyramids of Egypt still stand and we can make glass that is mechanically superior to limestone in almost every way.
However: data written on a sufficiently small scale may well prove fragile. Tiny oxidations of trace elements, tiny mechanical distortions or elastic deformations can ruin it. It's only on the nanometre scale, after all.
Possibly free standing glass blocks with data sitting inside cavities inside structural blocks will mitigate this. Or you could try using exotic glass, like nearly pure silica or nearly pure alumina or whatever they are currently experimenting on.
(EDIT: As per a comment by @biziclop, writing onto crystalline quartz even at the nanometre scaled is projected to have good data integrity more or less forever.)
One interesting, 'Rule of cool' possibility is using gold nanoparticles dispersed in the glass; this is how the Lycurgus Cup gets its colour. Gold in glass should be stable more or less forever; you just need to imagine how to encode data and get the nanoparticles into the glass in orderly fashion (near future tech).
This is my recommendation.
[](https://i.stack.imgur.com/Ib1bh.png)
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Glass is structurally sound; but I would worry about surface damage. One thing you might do is enclose your "data glass" in a shell of more glass. Perhaps a foot or even two feet all around, to take scratches, impacts and cracks. Maybe that's why they are arranged in structures like buildings; the glass shell provides both protection and physical space around the core glass for data access machinery to operate. (The core glass doesn't have to be rectangular, it could be pyramidal or even spherical.)
The outer glass can be designed tougher to protect the data glass. And the outer glass can be polished to make the data glass readable.
This might add to the mystery in your story.
Beat 1: Most of these big blocks have rough surfaces and are opaque white, but in some there are polished points, and we can see they have a "core" of a different kind of glass.
Beat 2: When we polish spots on a few blocks with opaque outer glass, we realize that all blocks have this "core" glass.
Beat 3: In trying to (non-destructively) determine the makeup of this core glass, our hero shines X-rays and lasers of various frequencies through the core glass, and discover some of these frequencies, at the correct angles, produce unexpected patterns, highly ordered. A surprise.
Beat 4: Our hero realizes this is data of some sort, and try to discover all the frequencies that cause this response, and unravels a protocol that produces a consistent and finite set of symbols for exactly half of the frequencies that produce an ordered response. But like hieroglyphs, our hero cannot decode them as words.
Beat 5: The other half of the frequencies that cause a response, our hero could not figure out at first, get figured out: They are images. Pictures in the glass.
Beat 6: Our hero understands *addressing*, how the combinations of frequencies used to elicit words, translated to the higher frequencies that elicit images, match up: This means the Text is attached to the Images. This lets our hero puzzle out the words, and the language, and start to decode the data.
And so on. The next surprise is in what it reveals, and what needs to be done about it.
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While the other answers talk about how glass will work and won't degrade over time, it might not be your best bet for long term, high-tech storage. Bullet proof glass is actually made of synthetic sapphires. These look almost identical to glass, but are much more durable. We can currently produce them on demand in larger sizes than you might be thinking of. Building-sized creations would be quite possible for a society even slightly ahead of modern day.
Impurities introduced into the creation process can colour the sapphires to almost any colour allowing for data storage in a visually appealing way. You can also have the angle of facets on individual crystals bending a laser's light as a method of data storage.
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**Humans are Highly Destructive of Pretty Useless Things**
You might have some buildings solidly, thickly surrounded on all sides including bottom by seamless glass that resists sandblast, warm enough to never freeze and experience frost-heave and frost-crack, carefully shaped so that lensing never melts internal structural members, etc.
However, the Pyramids have taught us, when humans are nearby who aren't invested in the sanctity of the object, they will steal it for their own uses. The Great Wall gets pieces of it stolen all the time. Just building materials from the nice outer shell of the Pyramids, and bragging trophies for many old buildings. This is true for primitive humans, stone age, modern, what have you. If something looks valuable, someone will try and break in to take it.
Roots of plants eventually work their way into all surfaces, and then into all solid materials. A low-water location with little greenery is the only place your glass buildings will remain unbreached after thousands of years. Possible counter : toxic building materials.
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No.
Glass is a liquid material like honey. Glass has no crystalline structure like stones have. Elder glass from past centuries, built in windows, flow down to the under edge of the plane window glass panels. The glass thickness is so double or more thicker, than on the upper edge of the plane glass. The flowing gets slowly but it flows. So your some thousands of year old building will shrink and get lower every century. Glass seam stable, but it is not. I was glass worker in past.
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I am building a world with islands floating in air, and I'm looking for solutions to loss of water from runoff/erosion (think rivers emptying off the side of the islands). The islands vary in size, with the smallest around the size of Manhattan, and the largest about half the size of Iceland.
A few limitations: sunlight does not reach the surface below the islands, and nothing comes from the surface to the islands; the islands may as well be floating in a void in terms of how the surface affects them.
Not all islands are inhabited, and those that are developed their science and technology while on those islands, so while a more efficient modern solution is possible, there has to be a reason life didn't die off before it was reached.
Given the limitations, is there any way to avoid the loss of water through runoff? Solutions involving science, magic, or both are equally welcome!
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## Option 1 the surface is mostly ocean
If the the surface be mostly ocean that supplies plenty of evaporation and would also explain why things that fall off are never seen again, they hit the ocean and sink. Evaporation is influenced by wind patterns as much as light from the sun, the ocean does not need to be well lit to evaporate. Coriolis effect alone will generate updrafts. Keep in mind you need a LOT of floating land to actually prevent light reaching what is below it.
Its impossible for nothing to be exchanged with the surface, air moves and there is no much you can do about that. A bigger problem is how are the floating islands still there, if they are being eroded all the sediment eroded away ends up on the surface. millions of tons of island is being lost every year. that means that, at least on a geologic timescale, new floating islands must be generated on the surface (volcanic?)
**Option 2** below the islands is a very thick layer of warmer air and clouds, most falling water re-evaporates , falling water does not stay a coherent stream air resistance breaks it into droplets fairly quickly. this can work with or without your deeper ocean layer.
does this layer of clouds make a lot of sense, no, but the neither does floating rocks. You already have gigatons of handwavium so it only needs to sound vaguely plausible.
**I can even see why way to get you cloud layer**, much of the clouds are not clouds but dust. Presumably whatever makes the islands float is also being eroded, and is washed off the sides by the rivers. But the fine particles can only sink so far before the "magic" keeps them afloat creating a layer of very fine dust. Since the particles will be banged against each other until they are so fine and light even a light breeze can carry them easily. This dust would also encourage cloud formation the same way cloud seeding does. this again also helps keep the below areas mostly dark. Although with wind patterns it can never be completely dark all the time, hurricanes for instance would create windows downward in their eye. Of course humans will only see it if they are cray enough to stuck their head over the side of an island and look down in the middle of a hurricane, so most will never see below the clouds.
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The bottom of your islands would be of basalt, granite or similarly impermeable rock. The edges have a lip, formed through natural processes (heck, it could be simple survivor bias - all islands that formed without such a lip end up as baren, completely eroded disks of pure rock floating around); or mystic/god-based intervention if you prefer.
Now, all your life-carrying islands have a circular basin of water on their edge, where all the run-off pools up over time. The processes keeping solid sediment from filling this up and leading to overspill could lead to interesting plot point; i.e., cleaning these channels regularly could be a vital task performed by a holy caste, etc.
For the time before intelligent life, there could have developed plants that somehow transport the sediment in those channels back towards the center through some evolutionary benefit. Endless possibilities. Unless you find a way to make this interesting, I would just handwave the issue before any kind of life existed. Heck, even solid matter could be infused by volcanic activities, or a great meteor impact.
On the inland, water is recovered in the usual way through rain. Again, seasons could be a nice story anchor - you could build really interesting weather patterns combined with streams in the ocean which let the island float into the watery regions yearly, or something like that.
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# Magic
If the island were floating in the air, and gravity was pulling it downwards, it would be simple to add a portal at the bottom of the waterfall and link it to the start of the river/stream. The water could continuously flow downwards and reappear in an endless cycle.
**Pros**
* Never-ending cycle
* No physical labor required (other than magic)
* Simple and easy
**Cons**
* Water might have passed through some questionable stuff going downwards to the lower portal
* Evaporation (depending on the amount of heat)
* Water droplets may be lost on the way down (accumulation will effect the amount of water in the future)
**Unsure Stuff** (for you to decide)
Does the magic have to be renewed?
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The first thing before we are going to give the reasoning behind why the water is not running off the floating islands is that why the islands are actually floating in the first place.
Floating islands should have a special ability to defy the surface's planet's gravity. The islands may as well have something to cling to, something like its land mass.
Therefore, everything includes the water above the floating islands will attract to the land mass of the floating islands, which is acting like the gravity for each individual floating islands. This will prevent all sort of things falling off the islands.
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what if the bottom part of the floating island has some kind of enchantment that kind of generate somekind of force field or something that keeps them afloat.
now when the water tun off the edges instead of falling off they are attracted by the field, and with gravity of something that also keeps the floating island not going anywhere , the water runs down at the bottom part neatly to the center of the island where the force that keeping the island afloat is the strongest and at first it looks like a reversed sea / lake, and then erosion makes the water breach the core of the island and making a circular flow.
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## It's Hot as Hell Down There
The farther down you go, the hotter your world gets. This means that all the rivers pouring off of your islands spills into a hot abyss and boils the water turning it into clouds giving the sky below the appearance of an endless sea of clouds, but falling water creates weather patterns that push clouds back up above the islands where they cool and rain back down onto the islands creating a complete water cycle even without any land or oceans below.
[](https://i.stack.imgur.com/y0mLH.png)
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# Ignore it
This isn't just a flippant "you should hand-wave it" answer. In reality, we have to be taught in school where the clouds come from. In your reality, it's a little more nebulous, but it's just as invisible.
Let's rationalize the entire system to be a 100-mile thick layer of gas giant clouds, where the islands are lighter-than-the-lower-air chemical suds encrusted with rock. The water that runs off of them would fall into the lower cloud deck, and rain would form in the clouds above you. The entire system would be unfathomably huge, but the water from below would still turn into clouds above, which would rain water down on the floating rocks. The rocks would likely have basins where the water would collect in lakes, and maybe even seas.
The point being that the water cycle will sort itself out once you've answered the more important questions, like "what is the rock cycle" and "why do we have volcanos."
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The soil in these islands is made of impermeable material that is also very resistant to wear from water flow.
Seabeds come to mind. If they were permeable the oceans would have penetrated the seabeds and Earth's surface would be dry. Also oceanic trenches are formed from plate tectonics and not from erosion.
It may be that the floating islands were formed from chunks of the marine bedrock that for whatever reason began to float.
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#### You don't stop it completely, you replenish what's lost
You cannot stop soil loss, even if you managed to stop all the water runoff there is the dust that is carried away by the wind and the small runoff caused by the occasional flooding that cannot be contained, on the long term the island would erode away. All the land we live in is a dynamic environment and the coastal land is extremely dynamic. Either sand is deposited by the sea currents or it is carried by the rivers from inland and partially eroded by the sea currents. Strips of land covered by mangroves slow down the exchange, but do not stop it completely. See what is happening to all the river deltas around the world, the increase use of the river waters reduced the amount of silt brought from inland and all the coastal areas are eroding.
The only solution is, first to reduce as much as possible the loss with a ring of mangroves around the island, but on the long therm that would not be enough. Then if you assume nothing comes from the sea currents it must be brought by the wind. The islands might be in front of a desert land, like the islands of [Cabo Verde](https://en.wikipedia.org/wiki/Cape_Verde). In this world dust storms will be very frequent and they will bring sand from the desert.
Alternative. The island are trapped between two sea current that created a small loop downwind from a hotspot. A group of active volcanoes, that just pop out of the surface, spew a lot of ash that often deposits on the islands.
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I have built a fantasy world and solved it in this world.
In this world, down is a real direction. Things made of the element earth pull things above them down. The range this happens grows with the size of the object in question, and it extends to the sides to a certain limited extent.
Water shields this effect somewhat.
Thus, water is pulled down by the islands, and flows off the sides. When it does so it ends up in the void, which is dominated by air.
Elemental Water in an area dominated by air forms clouds. These clouds in turn migrate.
When the clouds end up above a large amount of elemental earth (an island), it pulls the water down out of them. And you get rain.
If enough water gathers in the domain of air, it will clump and form a major storm system, or rarely an ocean. Oceans are like islands, but made of water. They are universally surrounded by storms.
Bad things happen when an ocean and an island intersect. That results in a flood!
The bottom of these islands is going to have a limited amount of down-pull (aka gravity), which means you can build structures hanging off the bottom. It is, as mentioned, dark down there.
As gravity is a product of elemental earth, ships that travel between islands use specially treated and reinforced wood to produce a local gravity field. If you are cast adrift from such a ship you just float in the void.
A lighter weight solution are wings, where you use the lack of gravity and large surfaces to "swim" through the air.
Below a certain threshold, islands don't produce sufficient gravity. These tend to get slowly pulled towards the nearest island.
Above a certain threshold, islands actually repel each other; so they are less likely to merge.
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# Ice Ice Baby...
There is a layer of really cold dense air just below the level of the islands caused by a permanent thermal inversion in the atmosphere. Water vapor accumulates and freezes on the underside of the islands in this cold zone. Gradually this ice builds up until water that flows off the surface of the islands also encounters these ice layers and starts adding to them. Eventually every island ends up being surrounded and contained inside an ice-bowl. The water near the center island remains liquid because it is constantly replenished with warmer water from the island but water near the edge tends to freeze into a **ice dam** because of atmospheric wind blowing up from the cold zone.
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Keep your water in solid form.
This won't entirely stop water flow, but it'll slow to a glacial pace.
Thanks to the adiabatic lapse rate, it's just a matter of altitude. Here on earth it's about -10C/km.
Keep going up until the snow falls; problem solved.
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Water coming on to land: precipitation.
Water coming off of land: evaporation.
If evaporation>precipitation, there is no runoff.
If precipitation>evaporation, there is runoff.
Now this limits the biomes you could worldbuild on these islands because there's a word for places where evaporation>precipitation and that word is 'deserts'. Anywhere verdant has to have an abundance of water.
One workaround I can think of is an aquifer in the belly of the island, replenished by intermittent/seasonal heavy rains, which feeds tree roots and springs.
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Per [this question](https://worldbuilding.stackexchange.com/questions/118966/restricting-antimatter-practical-rather-than-legal-measures) I've been giving thought for some time to restricting the use of antimatter and it occurs to me that an object lesson in what can go wrong might go a long way to discouraging its use.
**To that end what would the aftereffects of a reasonably large amount of antimatter going off look like after several hundred years?**
For the purposes of answering the question one metric tonne of antiprotons broke containment on, for all intents and purposes, the surface of the moon three hundred years ago. Does the site still glow because of daughter isotopes or is it simply a big hole in the ground, how far would the debris be spread etc... The focus is really on what the site *looks* like, from L1, what legacy remains from this largest industrial accident in history.
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Contrary to L.Dutch's statement above, annihilation of baryons *eventually* produces only gamma rays, but in the short-to-medium term you get all sorts of interesting daughter particles not all of which are unstable. Only electron-positron annihilation gives you nothing but gamma rays.
According to the [source of all knowledge](https://en.wikipedia.org/wiki/Annihilation):
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> *Thus, when a proton encounters an antiproton, one of its quarks, usually a constituent valence quark, may annihilate with an antiquark (which more rarely could be a sea quark) to produce a gluon, after which the gluon together with the remaining quarks, antiquarks, and gluons will undergo a complex process of rearrangement (called hadronization or fragmentation) into a number of mesons, (mostly pions and kaons), which will share the total energy and momentum.*
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In a vacuum, these annihilation products can travel quite some distance before they decay into gamma rays or stable particles such as electrons and positrons:
[](https://i.stack.imgur.com/XTx5j.jpg)
The mostly likely reaction involves the production of some neutral pions (shown as π0) which decay almost immediately into high-energy gamma rays, and also some charged pions (shown as π+ and π-) which have a short lifetime but are also travelling exceedingly fast and can therefore interact with nearby matter. The pions decay into charged muons (shown as μ+ and μ-) which are even more stable, and can travel for quite some distance in a vacuum. These, too, can interact with surrounding matter. The pions eventually decay into electrons and positrons (shown as e+ and e- respectively), the latter of which can annihilate an electron either produced by the decay chain or in surrounding matter producing more gamma rays
Those early charged pions have a kinetic energy of >200MeV, which does exceed the atomic binding energy of most light elements. The interaction cross section with a nucleus will be small, and the chances of the pion scattering off the nucleus will be reasonable, but some proportion of nuclei in the matter surrounding the blast might in fact be fissioned. Similarly, the >200MeV gamma rays coming out of neutral pion decays can also cause [photodisintegration](https://en.wikipedia.org/wiki/Photodisintegration) of nuclei.
Certainly, nuclei as light as aluminium might be smashed up by this process... possibly slightly heavier nuclei too, but I'm unclear on that. The resulting fragments *may* be radioactive, and they *may* be long lived unstable isotopes. The amount of induced radioactivity is obviously going to be nonzero, but it isn't clear how much there will be (and the question might be too hard to answer).
An uncontrolled release of bulk antimatter is also going to result in some of it being blasted away from ground zero by radiation pressure without necessarily being annihilated immediately, as you'd want if it were an antimatter rocket or warhead.
This means you've got an expanding shell of ionised antimatter that can also interact with surrounding material. Individual antiparticles will eventually interact with a matter particle, but obviously a single antiproton or antineutron cannot annihilate anything larger than a hydrogen-1 atom. Anything larger will end up being being transmuted into a different isotope or element, and the resulting release of energy by the annihilation will be soaked up by spectator nucleons which may in turn cause the atom to fission.
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> Does the site still glow because of daughter isotopes
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Normal nuclear blasts don't have a radioactive glow in the aftermath, and antimatter blasts are no more likely to produce such an effect.
There's some scope for long-lived radioactivity, but in the absense of neutron activation and waste actinides from any fission byproducts, it seems likely that it will be much less. Even more so for the moon which has less metal than the Earth does, given its lower density, and it is often metals in the soil and rocks that undergo neutron activation to produce that long lived background radiation after a nuclear explosion.
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> or is it simply a big hole in the ground, how far would the debris be spread etc...
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Some of the debris will certainly exceed local escape velocity. It will likely hit Earth, though I suspect that with only a tonne of antimatter (equivalent yield 40 GT) there won't be enough to cause an exciting meteor shower. The flash will probably be visible to the naked eye if you were looking in the right direction, and there might be some satellite casualties from debris.
You'll get little tiny bits scattered all around the moon's surface, but mostly what you'll get will be a nice big hole, not too unlike the other nice big holes already there.
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Regarding the possiblity of a moon-shattering kaboom raised by the square-cube law, consider Tycho crater:
[](https://i.stack.imgur.com/lsHcOm.jpg)
Its a biggun... >80km across, and clearly visible from Earth (possibly with the aid of binoculars, if your eyes aren't great, but even so) but there are plenty of larger craters on the Moon, which remains resolutely intact.
I wasn't able to find much good research on the nature of the Tycho impactor, but having a fiddle with the charmingly old-school-looking [lunar crater simulator](https://www.lpi.usra.edu/lunar/tools/lunarcratercalc/), I was able to come up with something about 12km across and travelling at about 15km/s for a total kinetic energy of ~1.5 x 1023J, or ~36 *teratonnes* TNT equivalent. Even if it were wrong by two whole orders of magnitude, that's still a much bigger boom than the antimatter cooking off, *and* it'll do a much better job of shovelling regolith and rock around.
A tonne of antimatter will make a fearsome blast, but still small beans compared to a reasonably sized space rock. The moon isn't going anywhere.
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[Matter-antimatter annihilation](https://scienceblogs.com/startswithabang/2010/11/22/why-making-neutral-antimatter) produces gamma photons, nothing more.
[](https://i.stack.imgur.com/RHRwt.gif)
When [gamma photons](https://en.wikipedia.org/wiki/Gamma_ray#Matter_interaction) interact with matter they can produce:
* ionization
* [photofission](https://en.wikipedia.org/wiki/Photofission)
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> Photofission is a process in which a nucleus, after absorbing a gamma ray, undergoes nuclear fission and splits into two or more fragments.
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> Gamma radiation of modest energies, in the low tens of MeV, can induce fission in traditionally fissile elements such as the actinides thorium, uranium, plutonium, and neptunium. Experiments have been conducted with much higher energy gamma rays, finding that the photofission cross section varies little within ranges in the low GeV range.
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Considering that the moon is not that rich in those elements, you won't have appreciable after glow.
As noted by PcMan:
As a general rule, antimatter does not bruise and infect other atoms with neutron bombardment the way nuclear fission or fusion reactions do. It just shreds the atoms, leaving either very much lighter atoms, or more usually just converting the lot into a strong flood of gamma rays that then just go on to massively heat up any unconsumed matter around it, making a huge thermal explosion not much secondary radiation. The residual glow-per-megaton of antimatter is a fraction of a fraction of the same size fusion explosion.
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I appreciate it that my fellow users have gone on extensive detail about the particles generated by matter and anti-matter interactions.
I am a big fan of both Starfish Prime and L.Dutch, but I must contradict both. You guys are focusing on the particles, but I wanna focus on the practical effects.
A metric ton of antimatter will react with a metric ton of matter to release 49,930,843,263,157 kWh, or about 50 petawatts-hours if we round it slightly up. $E = mc^2$ and all, converting joules to kWH. [Actually I used a calculator because I am lazy](https://www.omnicalculator.com/physics/emc2).
For comparison, [that is about 80x the sum of the yields of every nuke ever detonated](https://en.wikipedia.org/wiki/TNT_equivalent#Examples).
Now take into account that the Moon has about 1% the mass of the Earth.
And then check [this Kurtzgesagt video detailing what would happen if you detonated a 100 megatons nuke on the Moon](https://www.youtube.com/watch?v=qEfPBt9dU60).
That nuke would be a fraction of everything nuclear we ever detonated, and it would already be able to level every structure on the Moon due to Moon's small size and mass. I'm leaving an illustration of the shockwaves here because it is so beautiful.
[](https://i.stack.imgur.com/whLh6.png)
Source: the video I linked to a couple paragraphs above.
You throw in every nuke ever detonated at once on the Moon, then rinse and repeat eighty times...
For the record, the way the Moon gets damaged in this antimatter anihilation scenario is very different than if it had been nuked or hit by an asteroid. Practically all the energy will be in the form of gamma rays. For an analogy, the difference between the nuke and this scenario is the same as being hit by a bullet and looking through the beam of a particle accelerator with the same energy output on you. TL;DR a considerable portion of the Moon will be vaporized very fast, and a lot of matter will even escape her gravity well. That may cause some quakes. I don't know how violent those would be. I just imagine that the sheer amount of power being released might be enough to emulate the shockwaves of a large nuclear bomb.
There are two reminders that will last forever and which observers will be able to easily verify. The first is that any structure over the Moon built prior to the antimatter escape will be utterly destroyed. The second is that any map of the surface of the Moon from after the escape will have a really big crater that is not present in previous maps. How big? I imagine big as in visible with binoculars from the Earth.
Last but not least edit: I am not 100% sure, but I think the absurd amount of gamma radiation packed in such a tight place might cause [photodisintegration](https://en.wikipedia.org/wiki/Photodisintegration), which could lead to some stuff becoming radioactive. I don't know if this would make the resulting crater significantly radioactive - on one hand most stuff exposed to gamma does not go radioactive, but on the other hand, you applied a divine amount of radiation to a very small volume of stuff.
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Possible, but extremely unlikely. You may want to put some ammonium nitra... err, pardon me... some well chosen elements susceptible to generate radioactive byproducts nearby and you will need lots of them, the paths to achieve this is very narrow.
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The afterglow over hundred of years can be generated by the creation of massive amounts of slow decaying radioactive elements (not enough energy to do that, not even supernovae manage to get significant percentages of those) or decent amounts of radioactive isotopes with half-lives of tens or hundred years (not *that* many of those). All the isotopes with half-lives shorter than years (and there are lots of them) will show insignificant activity after half a century.
But let's see some details:
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The annihilation with antimatter by itself is a "clean" process - you had mass, now you have lots of energy. As very energetic γ rays.
The interaction of gamma rays with matter will produce very little amount of fissionable elements - you will need heavy isotopes with very long half lives that are "pushed over the edge" and decide to hurry up under the jolt of heavy γ bombardment. But those that rush to do it will only result in daughter isotopes with very short half-lives, so the extra energy will only add to that of the explosion.
In any case, heavy nuclei are rare on the Moon soil, not enough supernovae explosions to create radioactive elements and Moons around in the last billion years or so.
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There are two mechanisms on which creation of new radioactive species may still happen:
* secondary neutron-antineutron pairs generation, with the capture of the neutron by a light nucleus - given that the neutron-antineutron pair have high energies, the capture of the energetic neutron is unlikely, so you can discount this one
* fusion of light elements generated by the [inertial confinement](https://en.wikipedia.org/wiki/Inertial_confinement_fusion) under the pure radiation pressure (see also [NIF](https://en.wikipedia.org/wiki/National_Ignition_Facility) and [HiPER](https://en.wikipedia.org/wiki/HiPER)). However, the energy you throw by a puny 1t of matter-antimatter explosion is insufficient for a massive production of heavy isotopes with medium half-life - you'd rather need a supernova explosion and then running around it to collect the products from an expanding shockwave spanning some light-years.
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One way to achieve an afterglow would be for the energy released in the explosion to warm the place up so much that it emits [thermal radiation](https://en.wikipedia.org/wiki/Thermal_radiation). According to Wikipedia, a temperature of 4000 K would give a red glow, 5000 K would give a yellow glow, and so on.
The energy released by 1,000 kg of antimatter annihilating with an additional 1,000 kg of normal matter is given by E = mc2 ≈ 1.8 × 1020 J. If the accident occurs underground then the vast proportion of this energy could be converted to heat (otherwise more would be lost in the form of photons escaping). I couldn't find specific data about the moon, but we can make a wild guess that moon rock has a heat capacity somewhere on the order of 1,000 J kg-1 K-1. This means the energy released would be sufficient to heat about 4.5 × 1013 kg of moon rock by 4000 K.
For comparison, the moon itself has a mass of about 7.3 × 1022 kg, so either you'd be doing this to an asteroid instead, or the heat would dissipate to the rest of the moon via conduction and convection. But the explosion itself is also localised in a much smaller area which would be a lot hotter than 4000 K, so it would take some time for the heat to spread out to a mass of 4.5 × 1013 kg. The moon has a density of about 3.3 kg m-3, so if we assume the heat spreads out equally in all directions, it would form an approximate half-sphere of radius ≈ 19 km.
I'm not sure how to estimate how long it would take for the heat to spread out this far, or how long it would take after that for it to spread out further so that it stopped glowing; but if the glowing part of the surface has a radius on the order of 19 km it seems reasonable to suppose the glow would last for quite a while, and the centre of that radius would probably stay hotter than 4000 K for a while too. Given its size, the glowing area should be visible from space.
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Could a culture have free-market capitalism that never (or at least rarely ever) results in corporations, large trusts, or other such groups? This culture is made up of a single alien species that evolved naturally and has a non-humanlike mind. They have a government that collects taxes and does things for their people. There are other different cultures, some of the same species, and some of the different species
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The aliens could be **a culture with an aversion to hierarchy and authority**.
Human society is based on hierarchies. Every organisation in human society has multiple layers of leadership with each layer receiving orders from above and relaying them to those below. This is also how big corporations operate. That's just how human society works.
But such a system could be completely aliens to those aliens. Having someone who is "above" them and who can tell them what to do and what not to do in exchange for a monthly salary or some other long-term benefit is just something that feels inherently humiliating and unnatural to them.
So all their economic cooperation happens on a deal-by-deal basis.
There are no permanent employment relationships, just people one regularly does business with.
Their manufacturing industry could function on a co-working system. Factory owners rent workplaces at assembly lines to workers by the hour. Then they buy the products the workers made while working there. Their navy could work by crewpeople renting a place on board of a vessel. Then the captain (owner of the ship) pays them for each individual chore they perform throughout the journey. Any task which just doesn't work without someone coordinating people - like some larger-scale construction project - works by hiring a manager to complete the whole project, who then sub-contracts people for performing all the sub-tasks.
A prerequisite for such a culture would be a way to negotiate and make financial transactions in a very efficient manner. In the ideal case, there could be some mechanism for storing and transferring some form of currency in their biology. Perhaps their currency is some protein they store in their body which they can exchange with others.
This could in fact start the moment they are born. Each member of the species is born with a certain amount of "currency-protein" stored in an organ in their body. The primal instinct a newborn baby isn't crying. It's the instinct to offer some of that protein to adult members of the species (who might not even be their biological parents) in exchange for them taking care of their basic needs. That basic social contract - currency-protein in exchange for services and resources - continues throughout their life.
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The main reason why corporations tend to be dominant is because there are large economies of scale. It's a lot cheaper to be a big organization which makes stuff than a small organization. To prevent that, you need to have the race reduce economies of scale and increase diseconomies of scale.
One big one is specialism. Humans can get much much better at a single task, and so it makes sense to have lots of workers who are good at a small range of tasks. Your alien race may have the opposite situation. They have a wide working memory but a lower ability to focus, so they find it easier to learn a vast array of tasks than be an expert at a single task.
Another big one is negotiation. Big corporations can negotiate cheaper deals with their size. Your aliens could be very clingy, only agreeing to lower prices for close friends. The larger a group grew, the more expensive sourcing products would be.
Capital costs tend to be much cheaper for a big corporation. It's much cheaper to build one big building than many small buildings, or one big piece of equipment. You could give them some biotechnology like growing homes or equipment from trees or animals that can only work with a small number of people, not working for people who smell different.
All in all, these would make it a lot cheaper to have small groups than large groups, and discourage corporations.
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**Some simple precedents, early on, when their impact isn't clear yet.**
First, assume that they never developed the concept of a corporation as a legal entity apart from the members. To them, the only possible "corporation" is a registered commercial partnership of named individuals. During their equivalent of classical or medieval times, there might have been judges and lawmakers who thought that only people could sign binding contracts, either in their own name or with a *power of attorney* from those for whom they sign.
Next, introduce the precedent that in a partnership, any one partner is liable for all acts or debts of the partnership, including those signed by their agents with a *power of attorney* (which would typically define a scope of this power, like a maximum amount for any one transaction or a geographical area).
This works reasonably well for a master craftsman who is supervising a few journeymen and apprentices, or a family trading house with the patriarch in the home office and trusted family members in some branch offices. It would allow two or three people who really trust each other to cooperate. It breaks down at the larger scale, but then it *would be the law*.
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The VOC (1600) was probably the first "corporation" on Earth. Merchants, trade, currency have existed long before that. The value of a corporation lies not in its scale, but the idea of **limited liability**, in that someone can take a lot of risk but not have it ruin their lives when they can't pay debts later. Many empires have existed before corporations that dealt with managing assets over long distances.
What is there in place instead of a corporation? It's legally referred to as a *business* in some places. A person owns Alien Cola. They buy sugar from Alien Sugar. They buy water from Alien Processed Water (APW), who buys water from Alien Unprocessed Water (AUW).
A drought hits and AUW is broke without delivering water to APW. APW sues Alien Urist of AUW for breach of contract, to sell all his homes and ships and himself into slavery. Alien Medici feels sorry for Alien Urist's poor luck and offers to loan money to him to pay off those debts. When the drought is over Alien Urist pays back Alien Medici's loans and continues selling unprocessed water.
It's not much different to modern capitalism, and you don't even need the slavery part - modern people still do go bankrupt for their businesses and simply get limited in their options until they get out of bankruptcy.
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Absolutely. There have been many cultures without corporations. However, they were dominated by individual crafts people and individual merchants. Look at a Medieval European town which had the crafts guilds and merchant houses and is surrounded by individual famers who supply sufficient food for the town.
As soon as there were masses of people to feed, larger organizations developed. So the Romans had "families" which controlled a larger organization that could bring in the food needed for a city. One could join a "family" and be part of their structure. (Certain organizations still preserve that Italian "family" structure.)
Once there was wealth to be protected, other organization structures developed, both protective and "acquiring". Armies and navies developed to try to get and protect wealth.
So, if you want to keep corporations out of the society, you will need a mortality rate to keep the population under the size that could be supported by individual farmers, crafts people, and merchants. That can be done with disease, war, drought, or famine.
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Yes. In fact there have been attempts to formulate such an economic system on Earth in the recent past. The system is known as [Distributism](https://en.m.wikipedia.org/wiki/Distributism). The idea is that the means of production should not be owned by the state (socialism) or by capital (capitalism), but as widely as possible. In practical terms it means that there should be lots of small businesses freely trading with each other, rather than having a few large corporations. It still has a strong influence on the economic philosophy of Germany.
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A very bad experience with large corporation in the past could result in *extremely* strict anti monopoly laws preventing business expanding beyond ~500 people. But if going to a smaller amount such as 10-20 people maximum per business you will either have:
* A country that either has almost all heavy industry owned by the government to allow the necessary concentration of people to do many tasks.
* Foreign corporations establishing a large amount of small subsidiaries and dominating the economy.
* or have technology not advance beyond a WW1 level for this nation with extreme inefficiency of metals production. With most companies being either Production companies that make one or two things, design companies that licence their designs to multiple production companies each & companies such as restaurants, plumbers & grocery stores that don't need that much in the way of employees in the first place.
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Yes, and it wouldn't need to be *that* different from ours.
Muz said it best:
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> "The value of a corporation lies not in its scale, but the idea of limited liability, in that someone can take a lot of risk but not have it ruin their lives when they can't pay debts later."
> <https://worldbuilding.stackexchange.com/a/205962/581>
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You (yes, *you!*) could buy stock in any corporation and hope to profit from its activities. There's a risk that it'll screw up massively and go bankrupt, reducing the value of your investment to zero. But crucially, not *below* zero. You (yes, *you!*) could also buy a share of a non-incorporated company. That's more dangerous, if it goes bankrupt, its creditors can come after *your other assets*. That would make the value of your investment *negative*, and capped only by your personal bankruptcy. Might still be worthy investment, but you're more exposed to risk.
If corporations did not exist, companies could still get huge and operate similarly as today. But expect more conservatism all around, as each shareholder is completely exposed to all of the company's risk. Also expect less diversification, as rich people will have more to lose by investing a bit in a company they know little about. So, probably the economy would grow more slowly all else equal.
If we're postulating aliens, there's all sorts of unrelated factors that could compensate for it, adding up to an economy growing about as fast as ours.
Critics of limited liability argue that it's immoral, particularly when one makes a gamble and causes massive damages that can't be paid back, but shareholders can walk away with all their other assets and maybe even old profit distributed from that company. So, it's easy to imagine a society choosing to go without it even after knowing the gains it brings.
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**Alien Maoism**
The current phase of development is called preliminary socialism
<https://en.m.wikipedia.org/wiki/Primary_stage_of_socialism>
According to Mao's theory, this phase will be superseded once China has achieved the state of being a fully developed country. Assuming that this theory turns out to be practicable (it is still far too early to tell) then this will result in a state-directed planned economy with few to no private corporations.
One key implication of this theory is that if no corporations existed anywhere to begin with then the preliminary socialism stage would not be necessary.
So perhaps a culture with a different historical basis would move from the final stage, to the capitalistic stage, in a similar way with some constructs of capitalism being accepted within society but with extensive legal / social restrictions on the formation of powerful corporate entities which can directly challenge the power of the state.
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All of the answers so far have made one common assumption: that the culture is founded on **materialistic values** and **[consumerism](https://www.globalissues.org/article/238/effects-of-consumerism)**.
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> As hinted above, within the current economic system of perpetual
> growth, we risk being locked into a mode of development that is:
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> destructive, in the long run, to the environment a contributing factor
> to poverty around the world a contributing factor to hunger amongst
> such immense wealth and numerous other social and ecological problems
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There is no need to anthropomorphise this culture - to assign our materialistic human value system to it.
Imagine a culture where the acquisition of objects is irrelevant. Rather, their values are based on artistic and philosophical endeavors, not production and 'stuff'. A society that is not interested in nor even has any concept of the development and building of bigger, better, more spritzy 'toys'. A society very much in line with being populated by the likes of Socrates, Plato, Rembrandt, Picasso.
The extent of their materialistic interests begins and ends with the providing of the necessities of life. An agrarian society. Now place this society in a very lush world, where food is plentiful and requires very little labor to produce. Nutrition is universally available, and so abundant that food storage is un-necessary. Daily requirements could be sourced daily, and no heat or cold is required for preparation. A very temperate world where simple structures are all that is necessary to provide accommodation. No need for heating systems, air conditioning, protection from violent storms, no need to go 'vertical', or to have walls of any thickness. Think in terms of a world where tent-like structures are all that is necessary. Every need is provided for with minimal effort. The primary energy requirement is supplied by the 'sun', and what limited manufacturing is done, could be powered by water and naturally-sourced electricity - chemical batteries - and fossil fuels.
A society where individual craftsmanship is all that is necessary to produce all of the consumer goods desired. Where mass production is not only irrelevant, but rejected by a culture that cherished individuality and uniqueness in their belongings.
Indeed, we would be in a society much like very early human societies, where there were no businesses except the individual proprietor, who made stuff and traded it directly to the public. There was no such thing as an employee, and the concept of payment for human labor was unknown. Any 'helper' would either be family (and would receive and share 'benefit' communally from the collective 'wealth' of the family), as part of the 'family enterprise', or an apprentice, who was 'reimbursed' through room and board. The only mass 'employer' would be the state, in the provision of services - the 'court' and 'courtesans'. Again, they would 'work' for room and board.
The monetary system would be very basic, at best. The barter system would be the main method of exchange, since food, energy, and all necessities would be free to everyone. Perhaps there would be neighbourhood 'markets' where goods were exchanged.
Since 'wealth accumulation' would be a concept so absolutely strange and weird, there would be no financial system. When every individual could have whatever they needed for free, what would be the attraction of 'wealth hoarding'? The individual could not really DO anything with it.
Progress would be measured, not in how much better the 'stuff' was, but in how advanced the knowledge and artistic creations became. Poetry, music, art, esthetics, dance, cultural refinements (think: the early court royalty 'refinements' of Elizabethan times only ingrained in all of society, not just an elite segment).
Such a culture would have absolutely no need for large corporations or consolidated industries. In fact, without a concept of 'paid labor' (the concept that one person could 'own' the labor of another), they would be impossible.
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Realistically, how could a parasite become sentient? It doesn't have to be one that can control it's host like a yeerk from Animorphs, but that wouldn't be a disqualifying factor.
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Realistically, unless the parasite can generate and perceive radio frequency signals, and therefore communicate 'telepathically' with other members of its species, there is little reason or opportunity for a parasite to become sapient.
Parasitism typically requires that the parasite lodge itself somewhere on or in its host's body, and simply attach and begin feeding, none of which requires much in the way of brains. Since the parasite doesn't kill its host, it remains up to the host to feed itself and its parasite.
The only likely way that a parasite could become sapient is for it to evolve to use its intelligence to assist its host, in which case it is no longer really a parasite but rather is a symbiote, or for it to use some long-ranged non-line-of-sight communication method to communicate with others of its own kind to their mutual benefit but not the host's benefit. Such communication abilities are unlikely to evolve except on a world where organisms incorporate metals into their bodies.
Since parasitism imposes selection pressures minimising the impact upon the host - at least until it is time for the parasite to reproduce and have its offspring parasitise new hosts - the selection pressures are typically those encouraging simplicity over complexity, and low energy over high, and sapience is typically both complex and energetically demanding.
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**Intelligence came first. Parasitism came later.**
Your species starts as a small meerkat-like carnivore that lives in groups - social cooperativity and intraspecies competition leads to intelligence.
A subset of this species associates itself with large herbivores. In addition to catching and eating creatures flushed out by the big grazers they clean the herbivores of ectoparasites. Some of these ectoparasites seriously decreased the genetic fitness of the big herbivores so that is a serious win for the herbivores.
Some of these creatures in addition to cleaning off parasites take a sip of blood or meat themselves. Over time this subset does less foraging and more sips of blood and meat from large animals.
This subset gradually evolves to complete parasitism of their original hosts and others. Body size decreases and they become stealthier. The intelligence evolved by their ancestors persists, but in a degraded, degenerate way.
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**Spreading and feeding**
There is much literature and other media like games where you can see why parasites would want to get smart, even if it isn't said explicitly. This also has a evolutionary perspective, which we can actually see in nature. Like all organisns they want to spread.
Parasites exist in many forms. From fat worms that can become several meters long to viruses and bacteria. Some use existing 'biological infrastructure', like feeding, breathing or excrement, to spread. But some use some extra assistance to either protect themselves or help spread. A bacteria that uses cats to multiply can infect mice and make them lose their fear for cats. Rabies can cause fear of water to such an extent that spasms are triggered when trying to swallow. Cordyceps will influence ants or other insects to move to certain locations, grip until they die and then the fungus will grow out and spread. Each is a mechanism to control. This control is to try to spread better or for defence.
From there it really isn't a big leap for a parasite to start controlling more and more of the actions. First it might be to spread better and better, but at a certain moment the host might be more protected as well. The longer the host survives, the better it can spread. The parasite would start to improve food intake and possibly blend better into the society it works in, so it won't be rejected by other potential hosts and can stick around. The intelligence might not come from the parasite, or at least not at first, but might gain this ability at a later stage.
After a certain amount of control is established, the parasite/host organism can nearly be seen as one entity. That means that, if applicable, intelligence is the right strategy for further evolution. Meaning they can take the same evolutionary path as humans, because it benefits them.
It is a long, complex road to such parasites and they likely only infect one or two species at first. It is unlikely. On the other hand, humans getting this much intelligence was also unlikely. We see it could happen with humans, so the same could be valid for parasites.
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## Animal Husbandry based Parasitism
Humans used our intelligence to domesticate various animals such as goats, sheep, and cows. To these animals who we use for milk, we are by every definition parasites. In some cases, humans like those of the Steppe peoples have also been known to drink the blood of their horses while riding them.
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Others have gone into detail about evolutionary factors which work against the evolution of higher intelligence in a parasite. There are still ways for parasitic life to "find a way."
Another scenario which may work in conjunction with Willk's idea. Perhaps parasitism is only one stage of the life. Or perhaps the parasite lives inside a creature large enough to provide enough calories to support the parasite's sophisticated nervous system.
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The book "Parasite" by Seanan McGuire (author of somewhat schlocky urban-fantasy) has genetically engineered tapeworms doing this. Everyone has one now and they keep you super-healthy with their ability to adapt.
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> But in rare cases, especially for a brain injury, they can spread to the brain, "adapt" to it and accidentally take it over. Of course it's like a new brain -- they have to learn how to walk and talk, but are fast learners.
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Perhaps a parasite that integrates with the brain/nervous system, like a Neural Parasite from star trek, could become sentient upon integrating with the host.
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So in my questions about the intergalactic highway and simulated ship quarters I established a universe where the navy fights a cult of alien worshipers over star gates. 500 to 700 years in the future. I want the navy to have a “super weapon” that they can use to attack the cult’s heavily defended world. My ideas are:
**Planet cracking railgun**
This gun is mounted on the brand new UHFS Cayuga. The gun will be able to accelerate a massive shielded projectile to near *c* while it is going down the barrel. I want the gun to shear continents into pieces and destroy the cult’s bunkers and cities.
**10,000 megaton bombardment nuke**
This is also mounted on the new ship. It would be used to destroy the cult cities.
Which is more realistic and effective?
A question will follow regarding the details of the battle and the tactical situation.
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**Railgun**
Neither are particularly realistic. You're more likely to fire multiple nukes instead of a 10.000 megaton one. Firing things lose to C is also particularly difficult.
That being said, something often conflated with Railguns is your best bet. Coil or gauss cannons. It can be done without shielding, as you can operate in space and thus a vacuum. The shell can be suspended and launched by magnetic forces, reducing damage to the gun part of the ship. Any energy imparted on the shell will increase velocity, allowing you to put a lot of energy in the projectile.
Although it will be difficult to accelerate to C, it's not needed. There are idea's to just drop tungsten rods from sattelites. Simply their speed from falling to the Earth is enough for incredible devestation, while being near impossible to stop. Extrapolating this to your space combat, you can just put any (partly)magnetic material in a gauss cannon, fire it and watch the devestation. Potentially you just fire them from outside the solar system and can even get gravity assisted speed boosts from planets and the star before landing on the target. Having enough payloads on board is basically the only requirement for senseless devestation. It is all potential energy waiting to be released from there towards the planet. Finally, it is also less complex than atom bombs, depending on how far the railgun is developed. Less chances of things breaking.
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You should check out Wichell Chung's *Atomic Rockets* and 'Matter Beam's *Tough SF* Websites for realistic details on warfare and weapons in space.
The key takeaway message from both however is that at high C velocities **your ship is the weapon**!
Any vessel accelerated to high velocities accumulates kinetic energy, as do ALL the objects on that vessel.
Mr Chung uses the amusing example of a space ship traveling at a significant % of light speed who counts among its crew the ships cat - and, as a bi-product of the aforementioned feline, a supply of used kitty litter.
The ship is on an intercept course with a planet occupied by an evil genius or similar (well evil from the cats perspective anyway). Solution? Just dump a couple of kilos of used kitty litter out the airlock and then maneuver the ship off at a tangent to its original course to avoid a collision between the ship itself and the planet. Separate to the ship the kitty litter just keeps on keeping on!
Result? Multi-megaton death by kitty litter!
EDIT; So if the ship is traveling fast enough the choice of a weapon is pretty much irrelevant. Any mass that can be detached from a ship traveling at a significant % of the speed of light will do the trick. Applying the KISS principal one or more metallic 'darts' perhaps equipped with a passive targeting system and simple gas maneuvering retros to maintain target alignment will do the trick. As would a 'shotgun' spread of multiple small 'dumb' weights depending on the size/nature of the target.
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Have you ever heard of a Nichols dyson beam? Fascinating concept. Basically a Dyson sphere reconfigured into a Death Star.[](https://i.stack.imgur.com/hbGbH.jpg)
If you want hard Sci fi planet killers, you really can’t do any better. Combine it with a star gate, like the ones you have in your universe you can bypass taking centuries to hit the target.
But if you are on a budget and can’t afford to dome over a star, RKVs or relativity bombs are probably the way to go, and the concept is rather simple. Take a single 100 ton missile like the one seen here.[](https://i.stack.imgur.com/9GHNt.jpg)
Then all you have to do is get it up to light speed, aim for a planet and it will hit with enough force to make the meteor that wiped out the dinosaurs look like a fire cracker.
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Rock falls. Everybody dies.
You don't need relativistic speed for an asteroid to be deadly. The gravity well of the planet will give a good-sized rock enough speed to be a devastating kinetic impactor. That idea combined with tech is sometimes called a "rod of god" - a massive, dense object like a tungsten rod dropped from space. Add a few thrusters if your targeting isn't precise enough. Add rocket propulsion if you're not satisfied with just gravity - falling from outside the solar system can take a while.
If you need more sci-fi, launch the thing with a rail gun to give it a better starting velocity so it'll arrive just a bit faster.
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The most realistic of your two choices is the 10-gigatonne nuke.
Accelerating a projectile to the speed of light is an exceptionally difficult task, and is best done over scales of millions or billions of kilometres, or even more. Obviously building a gun with a barrel this long is impractical, regardless of technology. It requires absolutely mindboggling amounts of power, to the point where if you're present in the same solar system as your enemy you'd probably be better off using that power in a large number of much slower weapons.
Thermonuclear warheads on the other hand, even with the original Teller-Ulam design, can be scaled up to more-or-less arbitrary sizes. It might even be possible for us to build a gigatonne nuke today, not that it would be a very useful thing to do.
Such a nuke is probably excessive, though. Let me propose an alternative plan:
Probably should should start by softening up the planetary defenses.
If you've got big lasers, zap everything that looks military from a long way away, if possible. If *they've* got big lasers in hardened platforms (say, a small moon or asteroid) you should swat them with a long train of big rocks sufficient to overpower any defenses. Use some suitable nuclear engines to boost the rocks into a fast intercept trajectory; you've presumably got decent nuke engineering skills, so orion drives may be entirely practical here.
Finish off everything softer by throwing a load of debris into orbit on inconvenient trajectories, smashing up everything in near-planet space and triggering an [ablation cascade](https://en.wikipedia.org/wiki/Kessler_syndrome). This can be done with missiles. If you've got big lasers, they might be a cleaner way of doing the same thing, but really you want space around the enemy world to be extremely hostile to anything coming off the surface... it is easier for you to drop heavily armoured things *into* a gravity well than it is for them to fly them *out*, after all.
Once that's done, drop a cloud of nuclear warheads of moderate size (megatonnes, not gigatonnes), possibly armoured in nice big lumps of rock, and detonate them at the edge of the atmosphere. This causes massive [high-altitude electromagnetic pulses](https://en.wikipedia.org/wiki/Nuclear_electromagnetic_pulse). Note that antimatter warheads would be more effective than fission/fusion here, if you have them, because they produce a higher proportion of gamma rays in their blast even at the same overall yield. This will fry all sorts of electronic and electrical things on the surface, including power grids, and toast any electronics still functioning in lower orbits.
Finish off with a sustained asteroid bombardment, focussing on areas of known deep fortification. Keep this up for as long as you can be bothered; the more rocks the better. Spice things up a little by including some [salted bombs](https://en.wikipedia.org/wiki/Salted_bomb) to produce deadly and long-lasting nuclear fallout, to make sure that cracks in bunkers become lethal and to discourage anyone venturing out once the dust has settled.
When you go home, leave a bunch of observation platforms in high orbit to see if anything stirs on the surface. You should probably park a load of spare rocks and warheads with re-entry engines up there too for a swift automated response, in case it takes too long for human verification. Better safe than sorry!
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Firing a projectile near lightspeed from a ship is an impossible task.
First, you'd need stellar levels of energy to get to high fractions of *c*; second, the accelerator would dump the reaction momentum into the ship's structure, producing potentially lethal or hull-fracturing levels of acceleration; third, as with very large nukes, the damage would be too localized to have the effect you seem to be after.
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If you'd like scalpels for your super weapons, might I suggest the Ultra-Relativistic Electron Beam, or the [Macron accelerator](http://toughsf.blogspot.com/2019/11/hypervelocity-macron-accelerators.html)? The former even works rather well in atmospheres!
For UREBs, you avoid the issues of electrons spreading out due to having like charges due to the intensity of the relativistic effect of their speed. At TeV energies there are so many 9s after the decimal that time passes very slowly for them - and if you try to slow them down or push them to the side, you create intense x-ray radiation. Your options are "don't be hit", "have a very, very thick block of tungsten between you and the enemy", and "be deep underground."
And since it is an electron beam, aiming with magnets lets you quickly track different targets and even saturate areas with rapid sweeps not unlike a CRT in an old TV.
For Macrons, while you're not shooting these ultrahypervelocity dust grains nearly as fast, or in atmospheres, you can easily push them into the regime of impact fission, and 10,000 km/s is still very fast. This means you can use good old kinetics (albeit in an extreme case) and have more energy on the target than your accelerator had to use to accelerate the projectile.
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I am creating a universe based on medieval Europe and I was wondering how many types of currency would be needed for a medieval economy to work. Example:
* The US dollar uses cent, nickel, dime, quarter, half-dollar, and dollar.
* The euro coin uses 1, 2, 5, 10, 20, and 50 cents, €1, and €2.
I have been reviewing the use of coins in different historical medieval and pre-medieval periods, but the currency changed so much in short periods of time or coexisted with different types of coins that I have not been able to understand it. Thank you very much for your time.
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**You're putting the cart before the horse**
Coins reflect the economy — the economy does not reflect coins.
Well into the medieval period (and not completely without merit today) is the most basic form of economic exchange: bartering. I need bread and have chickens. You, my neighbor, need chickens and have bread. We negotiate how many chickens are worth a specified amount of bread. We know this today as the "rate of exchange" and it's an important term.
As economies, political ideologies, and political boundaries (e.g. "nations") grow the need to standardize the rate of exchange increases. This is what brings coinage into play. Paper and/or cloth is certainly more convenient when it comes to hauling around an object that represents a great deal of value — but back then it didn't last. Coins and/or other hard-object markers of value (like the [Rai stones of Micronesia's Yap island](https://en.wikipedia.org/wiki/Rai_stones)) allow for a controllable rate of exchange using something that will last more than a short period of time.
So, in the beginning is a basic unit of money people can use to negotiate the purchase of anything and, more importantly to the Crown, pay taxes. Because it's hard to prosecute a war when your warehouses are filled with only chickens and bread.
It's early in our economic history, so we'll call this first coin a *Seren* and by Royal Decree a *Seren* is worth one chicken or seven loaves of bread.
**But nothing lasts forever**
The problem is that as your economy grows, so does the need for greater precision and larger denominations. Eventually, some smart aleck notices that your chickens are smaller than your neighbor's chickens so your chickens are only worth half the decreed amount: 3.5 loaves. Now what?
Our ancestors solved the problem by [*shaving* and *clipping*](https://en.wikipedia.org/wiki/Methods_of_coin_debasement) coins. This is where the idea of "[pieces of eight](https://www.encyclopedia.com/history/united-states-and-canada/us-history/pieces-eight)" came from: people cutting coins into eight pie-shapped pieces because they needed *more precision* than the coinage of the realm had. The rate of exchange was too high.
It's also one of the many reasons why early Europe had such cool coinage: because it's a lot easier to cut a coin into eighths than it is into tenths. The decimal system makes a lot of sense ***after*** the development of inexpensive minting and printing.
So, now we have two coins: the *Seren* and the *Eighth Seren* lovingly known as a *Marie.*
**So, JB, what's your point?**
My point is that by trying to create the monetary system before developing even the basic history of your region (putting the cart before the horse) you're creating an artificial system that won't feel natural or will feel too much like today's monetary systems crowbarred into yesteryear.
How many coins do you need? As many as wanting. You therefore should first develop a *feel* for how many coins are wanting. If your history started with an arrogant leader who wanted the coin to reflect his/her enormous ego, you'll develop a "unit" coin (the *Seren*) that has far too low a rate of exchange and this will lead to the development of a lot of smaller coins (increments below one *Seren*). If it starts with too high a ratio, you'll end up with more coins of integer increments above the *Seren.*
"Just right" is the number of coins you, the author, believes reflects the complexity of your economy and the complexity of your world's history. It can be anything you want. There is no one "right" answer. Frankly, you really do want an organic in-universe feel, but you can do that with two coins just as easily as twenty as they both represent benefits and complications that you can interweave into your world and/or story.
*I didn't directly answer your question. I think it's a mistake to do so. What I've done is pointed out (a) why so many authors simply say "the adventurer gave some coins to the barkeep," (b) why so many RPGs use a hugely simplified system like copper, silver, and gold pieces, and (c) why knowing the history of your world is so important. Which is a long and wordy way of saying I taught you how to fish, because I'm pretty sure the fish I have to give you are inadequate for your needs.*
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We can probably look to historical examples for a plausible answer. So your reference to US coinage isn't too far off the mark. However, you're a little biased... within your own lifetime, it's certainly only that list. But in the last few centuries there have been additional denominations:
* The half-penny
* The two-cent
Also, there are bullion coins (made of gold, silver, and recently, of platinum!)
* The \$5
* \$10
* \$25
* \$20
* \$50
* \$100
Historically, I'm only aware of \$10 and \$20 coins though. So, we're probably talking about ten denominations that saw actual use. And not all were available simultaneously either, with as many as 7 or 8 at any given moment maybe being minted (though with circulation times being what they were in the 19th century, no doubt all ten were being used somewhere).
As a counter-example, let's use pre-decimal British coinage, because they were a little bit crazy with their stuff.
* 1/4 farthing
* 1/3 farthing
* 1/2 farthing
* Full farthing
* Half penny
* 3 farthing
* Full penny
* 3 Half-pence (1.5 pennies)
* Half-groat (don't even know what this is, but wikipedia lists it)
* 2 penny
* 3 penny
* Groat
* 6 penny
* Shilling
* Quarter angel (gold?)
* 2 shilling
* Half crown
* Half angel
* Crown
* Angel
* Half sovereign
* Half pound
* Double crown
* Half guinea
* Sovereign
* 2 pounds
* 2 guineas
* 5 pounds
* 5 guineas
Again, not all of these were being minted simultaneously. But I've also left out quite a few that were minted only for a few years at a time... these are the list that were minted for about a century at minimum. This is approximately 30 denominations.
Part of the reason there are so many is because this lists includes denoms that are pre-paper-money. (If we included paper money, we'd easily double the denoms for the US and most other currencies.) That's how it has amounts like the 5-pound coin (a minor fortune, especially if you're a Dickensian orphan asking for more soup).
So, anything from about 8 denominations on up to 30-40 isn't without precedent, and maybe even with most of those circulating or being minted simultaneously.
Now that we've covered that, we should really discuss just what is *needed*. Because if an economy needs another denomination, and if the country's planners are even slightly competent they will see the need and try to respond, no?
Coins will serve (in a medieval environment) the same purpose as paper money does for us today (or more properly, did serve us until the late 1990s). So on the high end, denominations need to be large enough for the largest transactions commonly occurring without using too many of them. In modern times, it'd be "can we fit enough $100s in the briefcase to buy our cocaine shipment", but in medieval times it would be "can this purse fit enough currency to let me smuggle in my sailing ship's worth of brandy" or something like that. Coins are small, and large denominations are going to be precious metal.
Exceptions: For the very largest transactions, like kings buying and selling their kingdoms to the Medicis to finance wars, transactions will occur in the same manner that these things occur today. A bank will put the amounts in a ledger, and keep track of the interest to the fraction of the smallest coin amount. You didn't pay for your house with a suitcase full of cash, and neither did I. So there's no need for the $10 billion florin coin.
On the low end, how granular are your transactions? The British had fractional farthings because the poor wouldn't be found with pound-coins (if they were, they were likely about to be shipped off to Australia), but the poor still tend to buy bread and what-not. They might be paid just a few farthings per month, but needed to make more than a few transactions per month (this is pre-refrigerator, pre-preservative food).
Between these two extremes, we can postulate that increments only occur every so often. If the two extremes are close, then there might only be a few intermediate values, but if they are extreme (as was the case in the British Empire), then there will be many intermediate values. And with less competent economic management, not all of these values will have available denominations, but the more competent it becomes, the more of those values will see actual coins. I really do like the Brits as an example of the most extreme you'll likely see.
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### None?
Economies can be built using currencies other than coinage. Even assuming (as you imply) we are not talking about a time when digital currency is practical, there have been times when exchange was based on weights. And before you argue that just changes the problem into how many *weights* you need, I'll note that sliding-countermass scales and spring scales don't have this issue.
Also, as per comments, this is assuming you even *have* currency as such. While it's true that something which served as "currency" has been pretty common throughout history, its use depends on at what level of the global economy you are looking. States, or well-traveled individuals might use currency, but individuals within a small community might operate entirely on barter, and may not even *accept* currency. (What good is a coin, after all, if no one accepts it as payment?)
### But more practically...
There is no good fixed answer. Rather, coinage tends to develop into whatever denominations are "convenient". The reason we have denominations is because it's awkward to pay for a car using a million pennies, both in terms of carrying them around, and in terms of counting them out in order to complete a sale. You want your smallest coin to be about the value of a very inexpensive item, but more importantly, to be a value that most people won't care about an item's cost differing being more or less by that value. Many would argue that the US penny is too small.
Once you have your smallest coin established, you want coinage in larger denominations up to an amount you would expect someone to pay cash rather than using a bank note of some sort (think "check", not paper money; for our purposes, paper money and coins are roughly interchangeable). These denominations should strike a balance between making sense in your counting system (e.g. why coins tend to divide larger decimal numbers nearly) and minimizing the number of coins. For example, if we had coins strictly in powers of two, it would minimize the number of coins in any transaction, but humans don't like dealing with powers of two and it would actually *maximize* the number of *different* coins.
In this respect, having a base-ten number system is a disadvantage. A species/culture with a base-16 system would almost surely have only coinage at powers-of-four values, since this is a pretty good "sweet spot" between not needing more than a few of any specific coin for a given sale, and denominations that neatly round up to "whole" increments of larger values (that is, values consisting of a single non-zero digit followed by some number of zeros). Five would also work well, but most humans don't think in powers of five, which is why we wind up with tens (and twos, like the \$20 and \$2 bills; the latter is real, if almost never seen in practice). But using *only* powers of ten would mean needing up to nine of a smaller coin, and that's getting to be a bit much.
A more practical system — assuming your culture uses base-10 — might be to alternate fives and fours (with twice as many fives as fours). We sort of have this with nickels and quarters, and with \$5 and \$20 bills. It's not hard to imagine eliminating dimes and \$10 bills, in which case...
### Seven
...pennies (1¢), nickels (5¢), quarters (25¢), dollars (\$1), \$5, \$20 and \$100 are probably sufficient. (For values above that, people will probably want to involve accountants rather than paying out of cash-on-hand. Keep in mind this also assumes that a penny is actually worth something. Also, don't think of these as directly relating to real currencies, or as literal "coins"; I'm trying to address your question which was about types of *currency*. "1¢" might be a chunk of a coin that has been cut into bits, where doing so is common enough to be an accepted way of "making change". $100 might be a brick of silver or gold; not something you'll see every day, and indeed something many people will never see in their life, but not so large that no one wants to ever deal in them directly.)
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"Medieval" means that coins have intrinsic value, except possibly very small denominations which may be tokens.
A direct consequence of coins having intrinsic value is that *all coins of all states* are accepted, their value being given by the amount of precious metal in them. Basically, in the Middle Ages coins were little more than standardized pieces of silver (and sometimes, rarely, gold) with a known fineness and weight. Nobody cared much in what specific coins a payment was made, provided that they totalled up at the agreed amount of silver.
Excursus: Originall a "pound sterling" was exactly that: one pound (pound Troy of 373 grams, or Tower pound of 350 grams) of sterling (= 92.5% fine) silver. Of course there was no such thing as a one pound coin, which would have been impractically large; the common coin in circulation was the penny, which was actually one pennyweight (1/240 of a pound Troy, 1.55 grams) of sterling silver.
Small denomination coins, such a a farthing (= 1/4 penny) were made of copper or bronze and were in the nature of tokens; they were good only up to a certain (small) limit.
Since coins had intrinsic value, they circulated and were imitated all over the world. Specialized traders, called money changers, exchanged exotic foreign coins (of which local people didn't know the weight or the fineness) into local (better known) coins.
So that in the end the best course is to take one historical set of coins and use it as such, or maybe tweak it a little. For example:
* In the Roman system, the basic coin was the [*denary*](https://en.wikipedia.org/wiki/Denarius), about 4 grams (1/84 or a Roman pound) of silver. It was soon arranged (1/96 of a Roman pound, 3.5 grams, 93.5% fine) to be almost equal to the well-known (at that time) Attic drachma, and in this form circulated all over the Old World for some three centuries. 1/4 of a denary was a sesterce (silver); 1/16 of a denary was an *as* (copper token). 25 denaries were reckoned to be equal to an aureus (1/45 Roman pound, gold).
As an indication of value, one denary was considered to be the pay for one day of (semi-) skilled work; at the current price of labor in developed countries, that would be about 100 US dollars or euros. (Excursus: How has the dollar fallen. The original definition of the US dollar was 25 grams of silver, about 7 Roman denaries.)
* In the system of Charlemagne, the basic coin was the penny (= *denier*, *denarius*) of 1/240 (1.8 grams) of a pound of 94% fine silver. (Theoretically 1/240, but in practice more like 1/260.) 12 pennies made a [*sol*](https://en.wikipedia.org/wiki/French_sol) (not a real coin, just a name of the weight of 12 pennies), 20 sols made a pound. The smallest silver coin was the half-penny.
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# You don't need your own coin system
Let's look at a historic example of a society that ran entirely on various foreign coins. They started to use foreign coins around 800 and we know nobody there minted any own coins before 995, and the massive import of foreign coins that were valued just like the local ones only ended around 1100. How did this society operate if they pretty much didn't mint their own coinage and how did it evolve?
# Of Svear and Rus, Danes and Norveigers
Well, starting around the year 800, vast amounts of silver (and golden artifacts) started to flood into the coffers of the various lords and then trickled down via trader of goods and slaves. To the Danes and Norveigers in the west and north, this influx came mainly from the west via the north sea, to the Svear in the middle, it came from the southern Baltic coast and via trade with their neighbors in either direction and the Rus in the east via the Wolga and even down from Byzantium, where some served as an elite mercenary group called Varänger.
## 793-1066
The cultures I mention there were mainly a set of farmer communities that didn't use a lot of money in itself. It was a bartering and service society: My comb for your hoe, my labor of the next three days for you shingles.
However, once they started to go on larger scale trade and looting missions (**that** is a Viking, a member of such a mission is a Vikingr), there was the influx of mainly silver coins as loot and trade rewards flowed into the modern Skandinavia.
This "golden age" commonly is dated to end in 1066. In that year, a descendent of the *mycel hæþen here* with the nickname "William the Bastard", after inheriting and consolidating the French area known as *Normandie* (given to his great, great-great-grandfather Hrólfr Ragnvaldsson aka Rollo in 911), did re-invade the British islands (where Rollo had come from), beat down the king Harold with the weakened army after he had just defended against another invasion from the Norveigers under Harald Hardrada. In the same year, Hedeby burned down, and many of the people there resettled to Schleswig, just a little down the river.
## The effect of foreign coins
The inherent value of the foreign coins in Scandinavia was the benefit, that it could be turned into something the Scandinavian people cared for much more than the coin itself - it was decorative and held a value for trade with other countries, where they imported blades and steels from the west and silk and slaves from the east, stone from the north and wheat from the south. Scandinavia had quickly become both military power and the extension of the silk-road in a trade network. Some of the large exchange ports were the following:
* Hedeby - Somewhat inland, this port's main feature was the short track over to Hollingstedt, and so it exchanged wares from the Baltic to the North Sea and vice versa. It took at times less than 3 days from the moment a ship entered from the Baltic into the Schlei to unload in Hedeby, cart the cargo to Hollingstedt and then load a different ship that went down the Treene and get to the North Sea. The track via the Skagerak in comparison took weeks.
* Ribe - protected by large islands north and south, it was a good anchoring spot for traders going southwards to the Frankian coast and was a perfect spot to sail west towards York.
* Roskilde - Well protected, this was a booming trade city that dealt with many of the wares coming into Scandinavia through the Skagerrak in the north, out of the Baltic in the south, as well as the wares that came from Jutland and Skane on both sides.
## Weight is Value
But the coins were inhomogenous: Frankian coins weighed 1.8 grams, eastern, Islamic dirham (which flowed into Scandinavia en masse in the 900s to 1000s) weighed 1.2 grams and were purer as times went on. How to solve that gap or pay for something that is worth only a fraction of a coin? It's rather simple: the money is not worth its minted value. It's worth its weight in silver. And as a result, coins were cut up to create what is commonly known as "Hackgeld". The parts then were weighed against a set of weights. In the eastern half of Scandinavia, these weights had often the shape of cubooctahedrons and seem to have used multiples of 1.2 grams pretty much.
## Distributing large amounts
But how was it feasible to evaluate the loot from for example Wessex, who paid 30000 pennies to be spared? Simple: those vast amounts were not weighed or counted, they were taken in large chests and only dispersed to the warriors surviving as spoils of war later, using - in one source - volume measure to ensure somewhat even distribution.
## Excursus: Multinational trade around 1200-1400
The Hanseatic League in the high middle ages still weighed (and assessed) coins to calculate local exchange rates based on what they asserted the pure metal in the coins to be worth. But at times the whole exchange of money was on paper in the trade depot's ledgers.
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From personal experience:
My home currency (BGN) experienced rather significant inflation in my lifetime, so limiting the diversity of denominations had to happen by itself. It was BGL before the 1000-to-1 denomination in 1999.
The traditional order of BGL/BGN denominations is profoundly decimal, just like modern EUR and manu others: 1/100, 2/100, 5/100, 10/100, 20/100, 50/100, 1,2,5,10,20,50,100 and so on.
As the value of the currency decreased, bigger and bigger denominations (200,500,1000, etc) were printed and the smaller ones were converted to coins or fell out of use because they were too small for trading anything of worth.
But in any single moment, only 6-7 of them, corresponding to ~3 orders of magnitude (1:1000), were in actual, widespread, use. Right now, we have 1,2,5,10,20,50 and not much used 100. We also do have 1/100, 2/100 and 5/100, but they are virtually never used and generally disregarded. Prices of most retail goods are rounded to 0.1 or even 0.5 BGN. 0.5 BGN is a cheap coffee from a vending machine.
Transactions of more than 5000 are forbidden in cash so in theory you never need more than a pocket full of money.
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A more math-backed currency (see [here](https://en.wikipedia.org/wiki/E_series_of_preferred_numbers), but a currency is probably better E2) could have an order of denominations like 1,3,10,30,100
7 of them (up to 1000 value) can probably cover all the social inequality present in the economy for everyday transactions. For bigger things you needs accountants and cashiers anyway, even in a medieval context (and banks are always here to help).
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Set on an icy world where weather forecast is alway blizzard everywhere, I am wondering how do modern day people commute if everywhere are buried under several miles of snow? What kind of transportation could easily navigate these snow en masse and how do they avoid collision and sinking on a busy traffic?
The first safest and fastest mean of transport to cross the English Channel without breaking the bank shall be bestowed the prestigious title of Titanic. (PAX the more the merrier)
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**For heavy traffic as well as everyday commuting, the most practical infrastructure seems to be tunnels under the snow-layer.**
This is an obvious solution because, since there is 24/7 blizzard as you say, common transportation across the surface will be difficult and, in some cases like planes for example, extremely dangerous (due to the almost non-existent visibility as well as the difficulty of flying let alone landing in strong winds).
So if you have "normal" vehicles in mind (cars, trucks, etc.), tunnels are an obvious and by modern standards pretty easy solution. For mass transportation of passengers, **underground trains** could be constructed between settlements. Tunnels also present the advantage of having good isolation and thus being easily heated.
In the cases where operating on the surface is absolutely necessary, you would need specialized vehicles like enclosed snow trucks that protect their passengers from the cold. If absolutely necessary, individual movement on foot could be facilitated by using skis or snowshoes, although staying for any significant periods of time in blizzard-like conditions is usually strongly discouraged.
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There are currently many cities located in alpine regions or in snowy areas. Although your scenario involves a city 'on the snow', rather than on land with snow on top, there are roads that need to connect these current-day cities together over snow.
So the options are:
* [Winter road](https://en.wikipedia.org/wiki/Winter_road): A road made of **compacted snow**. Once made it requires maintenance and has a limited lifespan, however it is conceivable that all roads in your city can be made by compacting the snow.
* [Snow road](https://en.wikipedia.org/wiki/Snow_road): A road which uses **compaction and a degree of water** (which creates ice) to enable roads that can bear higher weight traffic.
* [Ice road](https://en.wikipedia.org/wiki/Ice_road): A road made by melting the snow into ice to create a **thick sheet of ice**. This has obvious advantages in heavy-haul traffic, however vehicles need to be adapted to the road and are slow moving, often no greater than 25km/h.
For your buildings not to sink in the snow they need to be **elevated to prevent heating** from the building reaching the snow below and melting it. Permanent Antarctic Research Stations use insulated structures on a substructure of poles resting on **wide concrete pad footings** in the snow to prevent sinking.
It goes without saying that constant maintenance is required to ensure all structures and roads are sound - this would consume a fair portion of the maintenance of your city.
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Looking at our world,
Skis
Snowshoes
Sleighs
Tracked crawlers
Subways or simply trains in snowsheds, and for short distances enclosed passages to simply walk through
Ski-planes
You mention "buried under several miles of snow" - that's going to be quite packed. If the people are generally below it, they will tunnel. If above, they will traverse the surface, and develop various schemes for bridging crevasses
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Good question but it starts at an inconvenient point.
I would suggest this sort of process:
1. Assume an icy world.
2. Assume humans are living there.
(then...)
3. Figure out what they're eating and how they're making agriculture work.
4. Determine if that permits the formation of cities as we know them.
5. Figure out how the farms can transport sufficient food into the cities.
(finally...)
6. Figure out how people move around within cities.
Personally I think #6 is probably not going to be the most interesting worldbuilding question to answer about this place, but that's just me.
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Well, there are places on Earth in which it's snow-covered winter for the majority of the year. Surface transportation still operates.
One trick to transport is that snow (and ice) has a very low coefficient of friction, so sliding is the most practical mode, rather than wheels. Pedestrian transportation is usually skis (sliding on snow) or skates (sliding on ice), the commonality being sliding in the forward direction and not backwards to to the side. Skis distribute weight over snow (as do the less-efficient snowshoes) but skates are better where that's not a concern.
Vehicular traffic usually consists of skis or skates and some sort of gripping propulsion. A sleigh consists of skate-like runners pulled by a draft animal like a horse or dog. Snowmobiles are skis propelled by a gripping belt.
In cities near where I live it's not unusual to drive the same cars and trucks that are used elsewhere, but the tires are specially adapted to snow or ice by using different rubber formulations for better friction at low temperatures, different geometries (thinner tires are better in the snow, for example), and sometimes metal spikes or chains to improve traction on the reduced-friction surfaces.
The other consideration, other than lower friction, is usually visibility. Winters are dark most of the day, and even in the light a blizzard is hard to see in. The driving snow can stare your eyes and lead you off the (invisible) road and completely disorient you. We have specialized headlights on vehicles that are lower than regular headlights (they pick up the relief better) but you can still get quickly disoriented and it's amazing how quickly tracks disappear in a blizzard, and how easy it is to get lost when you can't see more than 1 meter in front of your face. If you're looking at surface transportation in constant blizzard conditions, I think the only practical solution is some sort of rail with heating or constant clearing operations.
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So, I was watching a funny movie about undead pirates when the realization hit me, I never once tried to create naval superiority for my Mary Sue. Well, guess I just do it now.
***Titanic 2: (n)Ice to meet you*** is the unholy offspring of [Project Habakukk](https://en.wikipedia.org/wiki/Project_Habakkuk), [CMF](https://en.wikipedia.org/wiki/Metal_foam#Closed-cell) and Patrick Star.
Titanic 2 is a 1.2 kilometer long aircraft carrier, designed exclusively for UAVs. roughly 4/5 of the ship's body (not counting the conning towers) is a homogenous block of Ultra-high-molecular-weight polyethylene, "alloyed" with an aluminum-based composite metal foam, both reinforced with a hint of graphene.
Something like this. Increase length to 1.2 kilometers, width to 180 meters and double the height.
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> Can you sunk a plastic bag with a torpedo, or set it on fire?
> I dont think so!
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> - Anon, moments before he was set on fire.
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The ship's material is buoyant, and unlike pykerete, is much lighter while providing the same, if not better, protection. Basically, Titanic 2 is too large and too simple to be sunken. Weaponized stupidity!
However, I couldn't solve propulsion. Titanic 2 is much lighter than her predescessors, as she isn't an artificial iceberg, but still very massive and I just couldn't come up with a powerful-enough propulsion system, equally as redundant as the rest of the ship.
**What propulsion system (with what modifications) should *Titanic 2: (n)Ice to meet you* use?**
**Update:** Since people kept nagging me about how aluminum is not suitable for this job, then FINE! I declare every instance of the word "aluminum" here to be changed to [Y-alloy](https://en.wikipedia.org/wiki/Y_alloy), a high-strength alloy that maintains its strength, even when subjected to high temperatures for longer periods of time.
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Titanic 2 should use multiple reactors and independent systems to provide a reliable means of propullsion.
However your Titanic 2 would be very vulnerable to missile attack. I shudder to think what would happen to such a homogenous block of Ultra-high-molecular-weight polyethylene, "alloyed" with aluminium-based composite metal foam, both reinforced with a hint of graphene, were it to encounter a high velocity surface to surface missile. It would make the Hindenburg look like a fire lighter.
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Many vessels in history have had two or more methods of propulsion.
Galleys have both sails and oars.
Most 19th century steamships had both steam engines and masts and sails. most large modern sailboats have both sails and motors.
The *Great Eastern* (1858-1889) had two side paddle wheels and four steam engines for the paddle wheels and another steam engine for the propeller. It also had six masts and a large amount of sails.
Many later vessels have multiple steam engines and multiple propellers. Many modern ships have multiple propellers in pods attached to the, ship and the pods can be turned in various directions for flexibility in maneuvering.
Many large aircraft carriers of today have one or more fission reactors to power their engines, even though they are smaller than your super carrier.
Therefore, I deduce that your super carrier would have hollow areas inside its unsinkable block structure, containing enough fission reactors - or possibly fusion reactors if far enough in the future - to power the ship.
For propulsion the atomic reactors would generate electricity and the electricity would be transmitted by wires to many propellers in many pods attached to the main hull of the super carrier.
For reasons of stability the massive nuclear generators in their hollow areas should be placed rather low in the ship. So they might be partially below the waterline, and thus could possibly flood with water.
To counteract that the super carrier should contain water storage tanks containing an equal mass of water as would fill the hollow areas containing the atomic reactors. If the atomic reactor areas start to flood, water can be pumped from the storage tanks into the sea to maintain the weight of the super carrier at a constant level, while pumps also pump water out of the reactor areas.
You may remember Tom Clancy's 1984 novel *The Hunt for Red October* and the 1990 movie based on in. The Soviet submarine *Red October* is supposedly equipped with a stealthy magnetohydrodynamic (MHD) dive to use only magnets, with no moving parts, to travel though the water.
MHD has been studied for propulsion of surface ships, submarines, aircraft, etc.
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> Marine propulsion
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> MHD has no moving parts, which means that a good design might be silent, reliable, and efficient. Additionally, the MHD design eliminates many of the wear and friction pieces of the drivetrain with a directly driven propeller by an engine. Problems with current technologies include expense and slow speed compared to a propeller driven by an engine.[14][15] The extra expense is from the large generator that must be driven by an engine. Such a large generator is not required when an engine directly drives a propeller.
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> The first prototype, a 3-meter (10-feet) long submarine called EMS-1, was designed and tested in 1966 by Stewart Way, a professor of mechanical engineering at the University of California, Santa Barbara. Way, on leave from his job at Westinghouse Electric, assigned his senior year undergraduate students to build the operational unit. This MHD submarine operated on batteries delivering power to electrodes and electromagnets, which produced a magnetic field of 0.015 tesla. The cruise speed was about 0.4 meter per second (15 inches per second) during the test in the bay of Santa Barbara, California, in accordance with theoretical predictions.[20][21][11][12]
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> Later, a Japanese prototype, the 3.6-meter long "ST-500", achieved speeds of up to 0.6 m/s in 1979.[22]
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> In 1991, the world's first full-size prototype Yamato 1 was completed in Japan after 6 years of R&D by the Ship & Ocean Foundation (later known as the Ocean Policy Research Foundation). The ship successfully carried a crew of ten plus passengers at speeds of up to 15 km/h (8.1 kn) in Kobe Harbour in June 1992.[2][23]
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<https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive#Marine_propulsion>[1](https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive#Marine_propulsion)
So depending on how advanced the society of your story is, the super carrier might use a MHD drive full time or part time.
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**Tugs**
This isn’t a vessel. This is a platform. Much like an oil rig you should move it to wherever it is you think needs that much UAV support, then ~~anchor it~~ (Anchoring is a stupid idea, keeping this ship moving is pretty essential, thanks to @ MorrisTheCat for pointing that out!) To that end you don’t want it to move under it’s own power: that would be exorbitantly expensive and hard to do, not to mention maintenance would be a pain.
So instead have a fleet of tugs. Preferably drone tugs, in keeping with your remote operation theme. Give them light armour, no weapons, heavy structural bracing and keels and huge, huuuuge engines, and then chain them to your carrier-berg.
They offer several advantages: individual tugs can be swapped out with ease. With a vessel that size you could even have a small dry dock for tug repair if you wanted. The loss of any one tug won’t completely cripple you (though you may need to take care with load balancing: more on that in a bit). Tugging and shunting offer you all manner of directional control for difficult maneouvres, and in the event of attack your small, powerful tugs can be tactically repurposed to help potentially damaged or incapacitated escort vessels.
The downsides are logistical complexity, additional vessels that need defending from both the enemy and the sea, and structural stresses due to unbalanced loads. All of these are helped by using drone tugs!!
Drone tugs can automatically monitor and adjust for various stresses on the coupling chains, automatically working as a group to perform even the most complex tugging operations. Drone tugs also don’t run into the logistical complexities created by squishy meat bags. All they need is fuel and repair.
Defence is a touch more tricky. International law on maritime drones gets tricky when you start bolting on weapons, but as these are tugs you wouldn’t expect them to have much of their own. Instead these will be heavily reliant on the shelter of their fellow support vessels. That’s easy in the case of enemy attack: as long as they’re sufficiently covered by point defence, AA envelopes and electronic warfare and anti-torpedo defences... *phew* ... they should be fine. Your escort vessels can take care of all that, right?
In the case of defence from the sea: tugs aren’t typically built for storms. Open sea isn’t what they do (Except for specialist platform tugs, and even they avoid storms that your carrier group might have to weather) They will capsize, flood and sink. But your tugs are drones! They don’t care about staying upright for the most part. Build them watertight, with a heavy keel, and they can flip all the way over without really inconveniencing anyone. You do need to make sure they don’t bash into other vessels though, and for that you need *relatively* calm waters. For example: the calm waters that can be found in the lee of a 1.2 KM long behemoth of an aircraft carrier. Cluster your tugs together on the leeward side of the ship, then use their drone-co-ordination to keep the carrier facing the correct way into the wind and waves. You won’t move fast, but should come out of the storm all shipshape and Bristol fashion.
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# Sails
Your vessel is stupidly light. It is also very large. So it can have thousands upon thousands of sails of all kinds and shapes. They would be very redundant and replaceable.
It could also pick up a hell of a speed depending on how it's built, once it builds enough momentum and if the ocean current helps.
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# Aircraft
Your carrier is stupidly light. It also has space for a large amount of aircraft, all with very powerful turbines...
When aircraft are stored in a real carrier, they are locked to it with things such as holdback bars:
[](https://i.stack.imgur.com/LyUHr.jpg)
Just bind enough jet fighters on the main deck through such bars, all pointing the same way, then turn the engines on. And as your ship conquers the waves, [apply appropriate soundtrack.](https://www.youtube.com/watch?v=y8OtzJtp-EM)
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# Dolphins (or Whales)
Train a few pods of dolphins to wear special dolphin harnesses which allow them to collectively pull your fighting barge where it needs to go. Of course, you power the dolphins with feed fish buried deep in its hold. Also, the barge has fishing gear so you can replenish your fuel at sea.
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Your drones should be electrically powered. The aircraft carrier is nuclear powered, with oodles of small reactors dispersed throughout the ship. Since you already have a ton of drones and a ton of power, efficiency isn't a concern -- stick some of those bad boys under water and have them push the ship (your drone propeller design may have to be somewhat complicated to handle two different fluids).
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### Frame Challenge:
You cannot keep that ship right side up.
IN order to be stable, the center of mass of a ship has to be below the water line. This is generally accomplished rather easily, having a hollow ship means that most of the weight is in the hull, and therefore the right way down. Some ships use weights to ensure stability.
However, your hull is a solid block of mass lighter than water. It'd start capsizing right out of the shipyard.
There's a reason ships aren't build this way. Even the wooden canoe's in the amazon forest are hollowed out to stay right side up.
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it's my first question here, I'll try to be clear.
I'm creating a story where there is a steampunk style civilization that has to face advanced civilizations in planetary and spatial battles.
I'm trying to create a steampunk army able to fly in an Earth-like planet and in space.
I think a new power source will be necessary for propulsion in the void, but I want to keep the steampunk style, so I'm asking for help in designing a zeppelin able to elevate high in sky till it arrives in space and then uses the alternate power source to get propulsion.
Which material should have the balloon to float thanks to helium but keep the shape in the void?
Thank you.
**Edit:**
Thank you all for your answers. Since other civilizations from my story use some kind of magic, I think my steampunk airship could use some magic too.
So I picked the answer @Willk provided and I'll use the hydrogen as a gas while the zeppelin remains in the surface of the planet. Then when it needs to rise into space, the hydrogen gets burned to gain altitude and then used as a rocket propellant to get out from the planet's gravity.
Then, when there is no hydrogen remaining, the balloon cover, displaces thanks to gears, shaping into solar sails as @Joe Bloggs stated to navigate the void since it don't have the need to run very fast.
Finally, when it's time to return to mainland, the sails could transform into some kind of parachutes to land safely, but I'm not 100% sure of this...
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Fast, schmast. Just bob up to the top and then a little boost - you're in space!
**Behold: the internal flame hydrogen balloon!**
<http://www.halfbakery.com/idea/Internal_20flame_20hydrogen_20balloon#1232972746>
It glows!
Part 1: Zeppelin full of hydrogen floats high. The envelope expands as it rises and air pressure decreases.
Part 2: At height, an internal flame (with oxygen fed thru the tube) burns hydrogen. The heat causes the rest of the hydrogen to become more buoyant, allowing a continued rise.
Part 3: At great height buoyancy can take you no further. There is not much atmosphere and also nearly no air resistance. Hydrogen in the envelope is now burned with the steam produced propelling the ship rocket style. This is the part where an extra heat source might be good. A fission boiler could heat the steam up to great pressures and increase the propulsive force it confers.
You could use the engine from part 3 for part 2 I suppose. Then it would no longer be an internal flame balloon, but it would be a more economical use of your hydrogen which is also your precious reaction mass.
Landing this will be problematic because you have used your hydrogen. Hopefully you can find some more in space.
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> I'm asking for help in designing a zeppelin able to elevate high in sky till it arrives in space and then uses the alternate power source to get propulsion.
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Most of the atmosphere is found at low altitudes (because of gravity). The higher you get, the thinner the atmosphere, and so the less bouyant a lighter-than-air vessel, like a zepellin, becomes. This means that balloons have a practical maximum altitude.
Specialised balloons have reached altitudes of [over 50000m](http://www.isas.jaxa.jp/e/special/2003/yamagami/03.shtml), but that's a long way shy of the altitude where space is generally agreed to begin ([the Kármán line](https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line), 100000m). More importantly, those balloons were designed to be *extremely lightweight*, with super-thin canopies. An actual zeppelin would be much heavier, having an internal framework and sturdier wrapping and larger amounts of cargo and so on, and so wouldn't be able to reach anywhere near those record breaking altitudes.
You'll need to engage your magic space drive whilst still very much in the atmosphere if you want to get up and out.
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> Which material should have the balloon to float thanks to helium but keep the shape in the void?
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The defining feature of steampunk zeppelins is that they're entirely impractical and impossible when you have to use real world physics and engineering. As such, the material it is made of almost doesn't matter, because you're basically building the thing out of magic and wishes.
That aside, zeppelins keep their shaps thanks to their internal structure. So all you need is to wrap your gas bags in a material capable of withstanding the internal pressure of the lifting gas whilst in a vacuum. We do in fact already have things a little like this already in the form of the [Transhab](https://en.wikipedia.org/wiki/Bigelow_Aerospace) inflatable space station modules originally designed for NASA and now being worked on by Bigelow Aerospace. Those specific designs will be too heavy for your needs (but of course, so are steampunk airships, so your steampunk magic will solve that) but the basic layered foil design should give you an idea of how to procede.
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A zeppelin doesn't really work in space, as a zeppelin. You'll need rockets or something, and you won't get any lift from the blimpy bits.
But this is a steampunk universe. As the last physicist who ever had a great big new idea (Isaac Newton) always said "For every action, there is an equal and opposite reaction." It is entirely appropriate for you ship to react against the [Luminiferous aether](https://en.wikipedia.org/wiki/Luminiferous_aether), my good sir. As light is a wave, it must have as medium through which to travel. This medium is provided by the Luminiferous aether -- that special medium which spans the stars (and also provides a conveniently privileged reference frame). It must be significantly lighter than air, so in order for your zeppelin to provide lift you might need something lighter. Perhaps star-stuff itself?
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Weirdly enough, this is actually a real idea, although it requires 21rst century technology to attempt, not Steampunk at all:
<http://www.jpaerospace.com/images/atohandout.pdf>
The balloon envisioned is so large and fragile it needs to be assembled at the edge of space, where specialized airships bring cargo and supplies to a floating base for transfer. The stats are fairly impressive:
* The airship is 6000 feet long (roughly 2000 m)
* The transfer point is hovering at 140,000 feet altitude (about 45 km altitude)
* The ship uses Hall effect thrusters to accelerate to orbit over a 9 hr period.
[](https://i.stack.imgur.com/9oMal.jpg)
*JP Aerospace space balloon*
How well this translates into a steampunk environment is open to question. The need for a balloon that can make controlled ascents to 140,000 feet is pretty challenging already, and that is just one part of the overall system. Even with today's technology, they are not considering direct ascent, and the space going balloon is never going to come to ground level fully assembled (the winds will tear it to pieces, or make it uncontrollable in flight).
However, a multi stage system where the traveler changes modes of transportation at a station is exactly how Victorian travelers went places, so the esthetic isn't outside of Steampunkery (you can imagine porters moving luggage around in the floating space port) so with a bit of adaptation this might still work for you: the characters take a carriage to a train station, the train to an airship field, take the airship to the floating spaceport and then into space in the spaceship. Valet accommodations are part and parcel of the experience.
[](https://i.stack.imgur.com/I0ri5.jpg)
*"I believe you'll find the spacesuit in Harris Tweed far more comfortable, sir"*
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Going to space is not about going high (now that I sit in Northern Europe space is closer to me than Ibiza is), going to space is about going fast.
To orbit Earth you need to go at least around 7 km/s, to leave Earth you need to go 11 km/s.
No way to reach those speeds with propellers, especially once you are in the vacuum of space. Neither possible to reach using a jet of steam, because the needed mass would make the whole thing unfeasible.
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Well, if you handwave a super rigid, super lightweight material you can always use vacuum balloons. Basically don’t fill your envelope with anything at all, in Fact you pump everything out of it while keeping the zeppelin envelope a fixed size. Theoretically it’s the maximal possible expression of hydrostatic lift for a rigid body lighter than air aircraft.
Engineering wise it’s impossible to build (since materials rigid enough to make pressure vessels tend to be heavy) and not that much better than hydrogen, but with sufficient Unobtanium for the envelope you can’t do much better. It still won’t be good enough for the stereotypical steampunk airship though. Those things are just impossibly light.
This also doesn’t help with the fact that ‘In space’ is not the same as going fast enough to be anywhere useful. The people on your ship will still feel the effects of gravity pulling them down until you get your ship moving very, very quickly sideways. So you’d better have some good rockets on that ship of yours or you won’t really ‘go’ anywhere in space. You’ll just go up and down...
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For a different approach, it would be cool to have it set in a universe which has steampunk physics as well - take a look at <https://en.wikipedia.org/wiki/Luminiferous_aether> a now discredited 19th century theory of light that was superseded by the theory of relativity. It would potentially provide a really cool mechanism for zeppelins to travel in space - the zeppelins are made buoyant by a device which pumps luminiferous aether into or out of the hull to fall towards or away from the nearest body (ie the earth or the sun). This would also provide a mechanism for traveling across interstellar distances since you can just continuously fall upwards away from the sun and never have to worry about that pesky time dilation thing from relativity that keeps you from moving faster than light.
You would still need some mechanism for moving laterally against gravity. Also If you want to keep conservation of energy, the aether pump needs some sort of incredible power source - perhaps a nuclear reactor of some sort
This would have some very strange effects on the properties of light inside the zeplin - I invite you to take a look at what happens to sound in the thin upper atmosphere for inspiration: <https://physics.stackexchange.com/questions/496234/how-does-sound-change-high-in-atmosphere>
Edit: It also just occurred to me that in this universe there would be an analogy to supersonic... superluminous perhaps?
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i'd suggest an aether paddle wheel. you'll have to take large amounts of oxygen, water, and fuel with you to drive your steam machines, though. And a lot of food, 'cause you'll be going a while to reach the next planet.
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Building on [@Willk's answer](https://worldbuilding.stackexchange.com/a/157904/69488) but focussing on landing.
Once you have burnt all of your hydrogen for propulsion into outer space, your tank is essentially redundant. But vacuum is, naturally, even lighter than Hydrogen - so before coming in 'to land' just open your tank up, and ensure you have a tank 'full' of vacuum. Then, once you hit the outer atmosphere you can very slowly allow gases in from your surroundings to let you fall slowly to earth.
As a bonus, off the top of my head Physics would be on your side as well. Even if you let in too much air at any level, as you sank through the atmosphere the surrounding air would become comparatively more dense, so you would have a natural negative feedback on your downwards acceleration - a useful safety feature!
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I would like to propose being able to transport water at very low cost to any location on our current or near-future Earth. The mechanism of transport is technology based, and results in 100% pure H20 - therefore is instantly potable and both disease and parasite free.
It uses a device at the sending end, and at the receiving end, much like the [Stepping Disks](http://larryniven.wikia.com/wiki/Stepping_disk) used by Larry Niven's Puppeteers in the Ringworld series. The devices are "tuned" to ONLY pass H20 - this is how the water is purified. So the water will be drawn from the Oceans - from a location in international waters - probably the "dead zone" in the Southeast Pacific. The energy requirements are extremely low, and the sending mechanism is very simple and stable. It can run unattended for years if required. It would likely be placed on the Ocean floor.
I am interested in what forms of political opposition will be likely to happen. EG
* What NGO special interest groups will get in the way?
* What organisations will attempt to disrupt by force? (Eg Sea Sheppard or other Eco Terrorism outfit)
I am likely to write a story that is very dark and has massive conflict happening over water resource. This gives plenty of opportunity for conspiracy theories, and great big plots that span countries & continents, which probably does make for better reading. This is a big part of why I am asking the question, I would like to see insight into some of the possible things that could go wrong from a Political point of view. Ideally identifying specific organisations that in the opinion of the poster are going to have an issue with the aim of peaceful supply of water will be a massive help. Their objection may not be the peaceful supply of water - rather the means used to obtain it.
I can then do some independent research on those organisations. I am not fully conversant with NGOs outside my own country apart from Sea Shephard - so getting some idea of these would help a fair bit.
It would seem that dark stories are more popular, and at the end of the day - writing stories is about getting readers more than anything else.
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First, pure H20 is not potable and actually bad for you, normal drinking water is filled with dissolved minerals that are necessary for the body to work. Drinking distilled water can have the opposite effect of leeching you of said minerals when you excrete it.
**As for the actual answer:**
just about every nation would want this to the point they may even fight over this. But no one would really not want it. Access to useable water is a demand just about everywhere.
The only real potential opposition you would see would come from conservationists and naturalists. If you suddenly start making desert environments farmable you have effectively destroyed an entire biome and its unique ecosystem. No more cacti when trees can grow quicker. This may be mediated by some governments into compromised solutions of small desert preserves but again just about everyone would prefer lush forests to sandy deserts.
Environmentalists would be torn, even though they are destroying deserts. By making more plant sympathetic terrain this actually helps to cool the Earth.
**Note:** So people seem to be surprised by this notion that **pure water can actually be dangerous.** So here is a [link](http://www.mercola.com/article/water/distilled_water.htm) that hits a lot of key points, its not the most credible looking source but then again you are free to google "health effects of drinking distilled water". But please first educate yourself by searching "water universal solvent".
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I see another very powerful invention that this can be used for. You have found a way to quickly, cheaply, and in a stable manner create infinite energy.
Moving water is one of the most basic forms of energy creation we know with hydroelectric dams all over the world. Being able to take all the water from the lower point of the dam and send it back up to the top with little energy used would quite literally change the world forever.
While yes your invention was meant to give drinking water to everyone who needs it you also found an end to fossil fuels and coal power and nuclear power. You now have an infinite water wheel that will never stop or slow and can be ramped up and made all over the world to provide infinite energy.
Not instantly but there is no government or company that wouldn't want a private and encapsulated generator that never needs to be refilled and only needs the retinue maintenance of other hydroelectric dams. You would eventually be ending thousands if not millions of jobs of those that work in power plants and oil drilling and coal mining. The internal-combustion car engine would become obsolete as electric cars become cheaper and cheaper being able to be refueled for free. Fuel cell based cars that run on combining hydrogen and oxygen are even easier as you can split your clean water with your infinite energy into the gases for the fuel cells. Growing plants and food is easier as you now have desalinated water everywhere for your plants. Smaller or less developed counties can now have all the electricity they need for warmth or cooling. Not only do we have clean drinking water but now people can refrigerate food and cook it without a problem, which will lessen even more diseases.
This will lead to a world wide golden age as water, food, warmth, and power are almost all limitless. It's a revolution that would change so much for the better so quickly that for your question of which governments would get in the way, well the answer is none. This would solve so many problems that humans have been facing for millennial that there's no reason, besides pure malice, that anyone would oppose your invention. The creator of this device would probably be seen as a savior of mankind.
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Who controls the company who controls this tech will control the world. And some dastardly conglomeration or conglomerations or country will do their utmost to get their dirty paws all over this technology. Consider this: You might think that the technology might only be used to provide water to areas that need it. But a suitably nefarious someone might (whoopsie) "accidentally" remove water from a water-rich environment if they failed to be co-operative.
Even if you can somehow keep your company and technology out of the hands of the bad guys (who are sadly prolific), special interest groups would push their own agendas using the environment, feeding the poor in Africa, saving the giant panda or other convenient excuses to push their agendas. If your company isn't politically savvy it will find itself pushed from pillar to post by everyone and anyone with public or hidden motives.
There would also be repercussions from environmental lobbyists and groups, as this technology would almost certainly change the face of the planet - imagine a green Sahara desert - what would happen to organisms designed to live in its arid environment? What would the impact be on siphoning large volumes of water out of oceans? One might think negligible, considering how much water there is in the oceans, but would the siphoning process be killing aquatic life caught up in the machinery? Would removing even relatively small parts of the ocean change the ocean temperature? I think the environmentalists would have a collective apoplectic fit.
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My answer is specific to the United States political organizations, but other countries would have comparable organizations with similar political interests.
If the technology is able to transport water very cheaply, cheaper than pipes, i.e. imagine every water using/supplying device no longer requires plumbing it just has a water receiver. This could potentially put your company in opposition to every local water utility in the world. Most water utilities are small affairs, but together they have quite a bit of political power. There are a number of nonprofit organizations for water utilities: for example in the U.S. there is the [American Water Works Association](https://www.awwa.org/), the [National Association of Water Companies](http://www.nawc.org/), or the [Association of Metropolitan Water Agencies](https://www.amwa.net/) to name just a few. If your new water company is going to be in opposition to these groups expect political opposition from the existing suppliers.
In the western United States water is a big deal, large dams have been constructed and Trillions of dollars have been spent to store and allocate water from the large rivers among the western states. Water rights are a big deal. For example the outflow and distribution of the Colorado River is controlled by the [Colorado River Compact](https://en.wikipedia.org/wiki/Colorado_River_Compact) an agreement between the western states bordering the river on how to distribute and use this water. These agreements are a hot item in politics among the states involved; some states want more water, other states want concessions for providing the water. If your device is going to start altering the field significantly, expect the various state governments to either oppose or support this new technology depending on perceived benefits or losses of power. Also these large water systems are managed federally by the [U.S. Department of the Interior](https://en.wikipedia.org/wiki/United_States_Department_of_the_Interior), a federal department with a ~$20 Billion annual budget, this technology would vastly decrease their importance and political power, expect opposition.
All of these groups could of course seek to either outlaw, regulate, or control the new technology to varying degrees, depending on benefits to their own political power. For example the Department of the interior may oppose the technology unless it is under their jurisdiction and control.
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### Upfront costs per unit
Part of this will be the cost of making a transmitter/receiver pair vs the cost of operating it. If a tranceiver costs $1/square inch to make, then every city water system can abandon it's plumbing infra-structure. Every house has a receiver.
At a somewhat larger cost, cities like Phoenix, AZ that are currently pulling water from 9000 feet below the surface, and dropping the water table by 50 feet per year have a new lease on life.
If a 24" unit costs a billion dollars, then only large corporations and governments can use it.
(One thread that can run through your novel is the impact as the price per unit comes down.)
### Operating constraints
Your story will work better if there is a cost. Not financial, but in the form of constraints on its use. Is energy conserved? E.g. if you move water from Los Angeles to Denver, do you have to add energy the equivalent of lifting it up to Denver?
Does the water come out at Denver moving at the velocity of LA? This would allow you to weaponize it. E.g. there is a ~1600mph difference in velocity between Miami and Saigon. This becomes a way to tap energy from the system even if it does conserve energy. You're slowing down the Earth.
Can the system be tuned to handle any pure substance is liquid or gas form? If so, you just replaced all pipelines for everything. Keep filling up the fuel tank of a rocket while it lifts off? Even if you have to pay the energy cost for both the gravitational potential energy and the velocity difference of the rocket, it would still be far cheaper than conventional rockets.
If it's *really* cheap you can use it as a climate weapon. Make a gate a mile across and put the intake in an antarctic current with the output in the Aegean Sea and ruin the Italian wine crop and air condition Greece. Raise the temperature of the Humbolt current and destroy the anchovy fishery. Drop enough fresh warm water south of Greenland and turn off the gulf stream.
Flood low-lying parts of the Sahara. Evaporation and rainfall makes the areas around the new lakes fertile. This changes the balance of power. It also means the present inhabitants need to learn a new life style.
Build one the size of a 2 inch pipe, and give them away to every poor village.
If tuned to water, what happens if you try to pass an object containing water. E.g. Would a water bottle come out the other side of a transmitter empty, with the contents sent to Lower Goatsbreath, Manitoba? Does this become an instant way to dry food? Does it kill if the transmitter field is aimed at a person, drying them to mummy dust in a split second? Step out of the house, zot the house and kill all the termites. As well as the house plants and the goldfish.
This of course requires that the magic be outside the device.
### Just water?
If the units are small and light enough you could cover parts of the Sahara with black plastic. The air underneath gets hot. You can now replace every forced air furnace in the world. Or hot air balloons can stay up indefinitely. (Ok, you need two deserts on opposite sides of the world. Finally: a use for central Australia.)
Tune it to whatever metal. Put the device in the gulf stream the water passes through, the metal goes to the receiver. Tune to CO2, put the receiver 3000 feet underground in a salt water formation, and you take the CO2 out of the ocean. (Ocean holds a LOT more CO2 than the air does.)
If it can be tuned to any one molecule, but others pass through entirely without force, then it can remove that substance from a living person. If you are exposed to Cesium 137 from Fukushima, walk through the screen, and all Cesium 137 (or all cesium?) is removed from you. Run all the top soil through it, and people can come back to the area around Chernobyl.
Only simple molecules -- probably initially. But suppose later you can tune it to a specific protein: One pass through and you get rid of the accumulated protein that may cause Alzheimers. Or the poison in amanita mushrooms. Tune it to plaque in your arteries, and rejuvenate your circulation system. (It's more complicated than this...) Or tune it to a protein found only in Caucasians, and Uganda has the ultimate racial cleansing tool.
Clean up toxic waste sites? Tune to a spectrum of hydrocarbons, and clean up oil spills. Pull asphalt out of highways, turning them back into gravel roads. Separate rebar from concrete. Recycling becomes a series of towers with a chain of tranmitters. The first few pull out heavy metals and volatiles in plastic. Then common metals such as iron. If it can be beamed you could take all the iron out of a skyscraper or a dam. Take out all the aluminum of a plane in flight.
Can it be tuned to individual isotopes? The biggest problem in building an atomic bomb is separating the right isotopes. Disposal of radio waste becomes easier. Separating isotopes for specific medical use becomes easy.
Can you take all the water out of a parcel of air on a scale large enough to create rain shadows? Or put water vapour into a parcel of air for snow making at a ski hill?
### Solar system development
Hauling fuel is the biggest cost of moving stuff around the solar system. If it works with ice, you could transport ice from Saturn's rings to the surface of Mars, making that place a lot wetter. Siphon off 99% of Venus's atmosphere and store it on one of Jupiter's moons. Float one tuned to helium in Jupiter's upper atmosphere, and we'd never run out of party balloons. Tune it to Methane put the transmitter on Titan, and the receiver on Mars and crank up Mar's greenhouse effect. Tune it to CO2, and adjust the thermostat on Earth. If we can tune to isotopes, then separating hydrogen from deuterium from tritium becomes trivial.
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In my world I have an advanced civilization whose technology is Magic based. Their civilization magic can be found everywhere though, it is found most commonly among the educated and Wealthy class, but even the most poor will be exposed to some type to Magic.
The only problem with this setup is that I feel that it robs magic of its mysticality, thus making magic just another form of Technology. Is there anything I can do to still hold on to the mystical feel of magic in my world?
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Even if, Magic=technology, tech IS more mysterious than you may think.
So today, so many people use iPhones and computers. There's a huge amount of tech. But how many users actually know how it works?
They don't. They just know that it works.
It's mysterious to most people, except those who specialize in it. The difference is that we have the internet and can look things up.
Exposure to magic doesn't mean knowledge. So maybe there are ever-burning torches in every district, but your average poor person doesn't know or care how they work.
You can also delineate common magic vs. uncommon. Everyone accepts the things an average magewright can handle (like a light permanent light spell in a night club or the torches in the street) but anything beyond that is met with suspicion. Throw in some magical disasters related to the development of tech and a highly secretive order in charge of the development of magic for all.
One of the push/pulls I've looked at it is that magic is elite. Most people can't work it. So mages would want to make the lives of people better, just to stave off revolution.
You also may want to look at the advent of technology. Tech was/is frightening when it's next level. Early on people were afraid to toggle a light switch, because they had a fear of getting electrocuted. That's because they thought of electricity as lightning, which kills people, and they knew that lighting a room had something to do with that, but they didn't actually have an understanding of how it worked. In a few years they saw that they weren't harmed by turning on lights, and neither was anyone else. While they still didn't really understand, they accepted it as something in their lives.
Edit: Actually, the fear of being electrocuted in the early days of electricity wasn't totally unfounded. They hadn't yet figured out grounding, so you actually could die if things were not set up correctly or you touched a wire. Fires happened on a constant and regular basis because they did not yet have breakers in place. They used all sorts of stupid things for insulation like of all things PAPER. People would use a single light wire as the source for EVERYTHING in their home that was electric, so wires would trail down, and the circuits would get overloaded. If they touched it they would fry and everything would catch fire. Magic could be the same--as in, anything new and not completely researched might go on market.
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Consider leaving your world's magic exactly as you've described it, robbed of its mystery and mystical nature by its common usage throughout your civilization. Then let your point of view character (and by association, the reader) learn that magic is still very much a mystery, and a dangerous one at that.
Piers Anthony does this extremely well in the first few Xanth novels; showing magic as a pervasive aspect of his character's culture, then allowing one character to learn its hidden nature.
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In addition to my answer to [What's the smallest change to physics to allow magic](https://worldbuilding.stackexchange.com/questions/40949/whats-the-smallest-change-to-physics-required-to-allow-magic/40992#40992), which suggests there may be more magic in today's world than we oft believe, there are some approaches you can take to to make your ubiquitous magic seem more magical and less scientific/technological.
One of the key aspects of science is the search for the so called "natural laws." These are aspects of reality which are true everywhere and at every time. Science tries to identify these laws, if they truly exist, so that we can act on them. However, there are known patterns which science is particularly poor at predicting. One of these classes of patterns is those which include the actions of the observer. In science, it is utterly forbidden for the observer of a scientific experiment to influence its effects once the experiment is underway. They are expected to set up the initial state and then let the experiment simply evolve according to the "natural laws." This is then used to distill the essence of those natural laws into equations we can use. If we permit the scientist running the experiment to interact with it, we run into all sorts of issues like confirmation bias that the fundamental scientific process simply cannot deal with. Scientists take great effort to make sure their science is not plagued by this with techniques such as double-blind testing and repeatable experiments.
So what if your magic didn't follow this rule? **What if it was simply impossible to use magic without fundamentally altering the rules of magic in the first place?** The alteration might very slight, but perhaps the cumulative sum of all of the magic use in your world causes the laws of magic to slowly change shape. If they did so, science would never find a "natural law" which never changes, so they would have to reject the hypothesis that such a law exists. However, if the changes were smooth, you would find that magic didn't change 'all that much' over the short run This would be enough for everyone in your society to use a particular magic, but find that it eventually fails them.
It would also open an interesting door for non-scientific approaches if magic changed differently in different areas. Perhaps, in one kingdom, there's one particular kind of magic which changes slowly within its extent. Outside of the kingdom, that kind of magic changes much more rapidly. This would create a unique flavor of magic for that kingdom because they would have more time to codify "scientifically" this magic's behavior. Another kingdom may have a completely different feeling.
I envision this having a feeling similar to surfing. We all know the ocean's surface is flat, but every now and then a wave comes by. As long as you ride where the wave wants you to go, you're surfing. And, from what I understand, its a feeling quite unlike anything else. You would have groups of individuals chasing magic waves around the world, riding them as they go.
However, some individuals would see deeper than that. While most will happily ride along on the waves created by millions of magic users around the world, others may realize that their actions have side effects -- especially around some key nodes where magic is unusually stationary. These individuals would plumb the part of magic which science could not touch: the kind which can only be had by entering that magic and experiencing it for yourself -- manipulating it and having it manipulate you. Magic may behave quasi-scientifically elsewhere, but near these nodes, the mages would rule the day, not the scientists.
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You could include the fact that occasionally (only once in a great while) the magic will malfunction in completely unpredictable and drastic ways, and no scientist has a good hypothesis.
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Similar to answer from User127202, but an explanation for why science can never explain it:
Some types of cryptography are based on the data stream itself. In other words, if the last character transmitted was A, use table 1 to encode the next letter. If the last character was B, use table 2. This simple pattern can be reverse engineered, but it is possible to make an encoding that only can be broken if you know the entire data stream from the beginning.
Similarly, if you look at a fractal Lorenz attractor, knowing where you are on the graph tells you very little about where you're going next. You need the complete vector state to be able to trace the pattern. Even a slight roundoff error results in wildly different calculations. See also the Hugo-winner book "Three Body Problem".
If magic has laws that change over time on either a fractal or cryptographic basis, your scientists might be able to work out when the rules will change and even the range of possible changes, but because no one was around to record all the states from the dawn of time or because it is physically impossible to simultaneously measure every law to the absolute precision needed to compute ongoing states.
Given that, now you need a priest or oracle class whose job it is to announce when rules change (because they are constantly testing with tiny spells) and researching as fast as possible what the new conditions are.
We face this problem in cosmology: there is the potential for us to find a scientific principle that we can describe but never explain because the effect itself cuts us off from knowledge of the cause. There is some math work that suggests this MIGHT be true of dark energy, but nothing conclusive. So far, we've been lucky: our universe is generally both knowable and explainable, although weather prediction (distinct from climate prediction) is in the problem category.
PS: I must be getting old. Checked my library... I'd forgotten about Master Of Five Magics. It has one possible form of the kind of feedback-loop magic system I'm talking about: the rules change based on what people do with magic. <https://en.m.wikipedia.org/wiki/Master_of_the_Five_Magics>
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The way people in ancient cultures thought of magic seems to be pretty much exactly what you want: Magic was common but mysterious, because it was essentially asking gods and spirits for favors. I'm basically suggesting what ohwilleke already said, but I think I can expand on it a little more.
Magic as contact with the spirit world replaces the laws of physics with the uncertainties of personal interaction - and personal interaction with powerful people whose type of power you don't understand. Imagine an old person asking their grandchild to "to see if you can do something with your computer to solve that". Here a mage is less of a technician and more of a skilled diplomat with good connections: He knows of the proper channels and the (very complex) proper etiquette to ask for something and he is in good standing with the other party - but he doesn't necessarily know how that something he asked for is achieved.
Also, this way everyone can have passing knowledge of magic, small reasonably reliable rituals for small favors. Imagine someone in a foreign country with a phrase book: You can go into a German bakery and say "ein Brötchen bitte" and get a bread roll, if you hand over some money (i.e. make a sacrifice) and it doesn't matter that you mispronounce the ö. But if you want to do something more complex like rent an apartment and make sure that you get a decent one (what would be a normal price? what do I have to look out for?) - then you'll have to employ a "mage", someone who speaks the language and understands the customs.
Of course for this to work you would have to design (or at least hint at) a decently strange and incomprehensible spirit world - ideally one that has something to gain from its interactions with humans, so that a civilization could be built upon common interaction.
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easy, just make magic dependent on a mind. make a specific type of personality or mutually exclusive ways of thought one of the factors in making it work. if magic cell phones only work when nihilists build them, and magic railroads require a driver who is a go with the flow person, but the engine has to be built by a stubborn angry person. Then magical tech will be mysterious to most people even if they understand how they work.
Or maybe working magic requires a specific natural talent, but using a device they create does not, most people won't learn how they work because they can't do anything with the knowledge.
ohwilleke's idea of having magic tied to spirits or elementals that must be persuaded works well too, anyone can understand the machine but only a few people will know how to communicate with the thing that makes it work.
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If you've ever read the ["Twokinds" webcomic](http://en.wikifur.com/wiki/Twokinds), conditions are very similar to those you describe. It uses some very sound principles of realistically writing magic into the fiction story.
The author makes a clear differentiation between good and bad magic, and how it can affect the person using it. It's clear that magic is a very complex art and while anyone has access to it, it comes more naturally to some people then others. That means that a lot of people can use simple spells but the people at the top are very knowledgeable and can use very powerful spells. As previously mentioned, showing that magic is dangerous adds some mystery to it, and the more powerful the magic, the greater the danger.
The other thing you need to do is not to let the reader know too much — if you explain how the magic works and in too great depth, it's boring — and the reader can start to guess the rest of the story. It can help to hint at great untold powers and other magical beings that have know all the magic there is to know etc.
I'd also recommend you read through some other examples for inspiration and ideas.
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One of the big things about technology is that it is so damn predictable. If magic was facilitated, for example, by summoning demons or ghosts that had their own free will and weren't always easy to bend to your will, that would give it a completely different flavor than conventional technology. It could range from elf and the shoemaker type arrangements to powerful spirits with minds of their own that only powerful sorcerers could bind.
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I play a Table top role playing game that has a bit of magic in it. The social stigma around it has only recently begun to lift allowing people to openly practice it in most cultures. There is still a lingering taboo about it though. Also, most people need to go through a difficult (sometimes deadly) procedure/ritual to obtain more power. This sometimes leads to side effects that can disfigure them. While it is genuinely useful to have the price to pay for a greater understanding is too high for many people. It is also a bit of a blunt weapon, not so much finesse, so people are very cautious when trying anything beyond the tried and true.
I would say, in short, you can make investigating it further a known danger with a high cost, both physical and social.
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One way to get the mystery back is to make the magic non-generic:
Namely that there isn't one unified magic (that all mages understand and practice), but several different kinds, in some sort of opposition/mutual exclusion. So (for example) energy-mages can't master life-magic and vice-versa.
Another tactic might be to make the magic's strength/effects variable, depending on things the mages don't understand -- or don't *yet* understand.
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(Roughly) how long would it take to domesticate an alien beast?
Assume we have modern knowledge and techniques.
Assume the beasts are mammalian and similar biologically to Earth beasts.
As far as this question is concerned, anything that can be kept as a "pet" or used for farming is domesticated.
I am just curious as to how long it would take to change a wild animal into something like a dog, cat, horse, cow, pig or any other domesticated breed of animal.
Would it help if we could take the beast out of its natural habitat, or would this make the process more difficult?
Ive heard that some breeds of dog were wild as little as 300 years ago, but then I know that other breeds have been with us for thousands of years.
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I actually have a *very* exact answer for you. It would take about 20 generations (or less then 20 years if you prefer). How do I know? Because [we already did it.](http://en.wikipedia.org/wiki/Domesticated_silver_fox)
Of course this is a non-domesticated earth mammal. If your talking a truly alien species there are questions about how they evolved which could play a role in how easy they are to domesticate; a truly alien species will be so foreign to us it would take time just to understand it well enough to begin domesticating.
EDIT (updated below paragraph for accuracy)
On the other hand the above group wasn't trying their hardest to domesticate the species. While they did control mating they did it only by selecting those who did not flee from them, as an attempt to best emulate the selection process that lead to domestication in the past. If their goal was only to domesticate a species, instead of testing a hypothesis, they could use more through breeding criteria to accelerate the domestication process.
There are generally three major factors you need to domesticate mammals well.
1) willingness to at least partial tolerate humans originally, which generally means species that are not too timid or overly aggressive (though this is the least important quality I think)
2) species with relatively short growth from childhood to mating age, so you can fit lots of generations into a short timeframe.
3) social species. Domestication is about 'tricking' evolution into thinking of us as a potential pack mate. Most of the domesticated behaviors are actually pack behaviors reinterpreted. Trying to breed pack-like behaviors into a non pack animal would take MUCH longer.
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We **already know that some animals are hard/impossible to domesticate** like [zebra](http://www.loc.gov/rr/scitech/mysteries/zebra.html)
[Criteria for domestication](http://animals.howstuffworks.com/animal-facts/animal-domestication1.htm)
* **The right diet:** Picky eaters have always made life difficult for their mothers, so one can imagine the frustrations involved in keeping up an animal with picky tastes. Because many animals have specific dietary needs and carnivores get expensive to feed, humans can only domesticate animals that thrive on cheap, accessible food.
* **Fast growth rate:** The species must grow at a fast rate for herders and farmers to yield a timely return on the investment of raising it.
* **Friendly disposition:** Vicious animals by definition don't usually like it when humans attempt to bring them into captivity and won't let humans handle them.
* **Easy breeding:** If the animal refuses to breed under the conditions human captors can provide, then obviously, its period under human control is short-lived.
* **Respect a social hierarchy:** In the wild, if the animals form social structures in which they all follow a dominant member, then humans can establish themselves as leader-of-the-pack.
* **Won't panic**: Many animals freak out when they are restrained, kept in fences or perceive a threat. Cows, on the other hand, remain fairly complaisant and unflappable despite these conditions, making them easier to domesticate.
So OP's question is not answerable: **we do have criteria for domestication - we just don't have any alien animals to decide if they fit the criteria.**
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**Anything between few generations to forever**
For instance, in my super secret "Evil Overlord" lab, we managed to crosbreed velociraptors, which understand (and fullfill) all my commands. Wha... What? They are loose again? Excuse me for a moment...
Now, on serious note:
**What kind of animal is it?** Looking back on Human history, we were more lucky with the herbivores than with the carnivores. In other words, domesticating "space cow" is easier task than domesticating "space dog"
**How intelligent the animal is?** I dont want to say it should be *dumb as a sheep* but truth to be said, somewhere I heard that sheeps were actually the first ever animal to be domesticated.
**How big and strong is it?** Yeah, we managed to domesticate even the Elephants, but still it is easier task to domesticate "space hamster" than trying the same with "space whale"
And, last but not least
**What does make animal domesticated?** We still go to the sea to hunt for the fish. But also, we breed some fish species in controlled area to get meat. One example is Czech traditional "Christmas" fish, the Carp. Does it make the fish "domesticated"?
The same could apply to dears or to the boars. We keep them breeding and then we hunt them for meat. Sometimes we breed them in controlled area "just for meat". Does it make them "domesticated"?
Or do you just really want also "pet velociraptor"?
What? They are loose AGAIN? Who taught them to open the cages? Uh... you are one clever girl
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Depends on a lot of things, the natural disposition of the animal to begin with. Also it is pretty easy to make 'pets' out of animals. People have pet tigers, though most of them are still very dangerous.
As someone pointed out house cats are still debatable about being truly domesticated.
I think there might need to be a distinction between domesticated and tamed.
Domestication - a population of organisms in order to accentuate traits that are desirable to the cultivator
Tame - reduced from a state of native wildness especially so as to be tractable and useful to humans
There are a lot of tamed wild animals used as 'pets' but they are not domesticated. And there are a lot of domesticated animals that aren't tamed. Tigers can be tamed, cattle are domesticated.
The Dodo was almost domestcatable when it was discovered, a few generations could have made them the new chicken. Cats have been household pets for 1,000's of years and are still not truly domesticated.
But a few dozen generations is probably the average (WAG) to be well on the way to domesticated. (elephants live ~60 years, dogs ~7)
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Possibly no time at all. Domestication basically is getting the animal not to see you as a threat and so be stressed or unmanageable. The dodo had never encountered humans before, so did not see us as a threat; it effectively was tame because it was an alien species. Farming dodos would not be any different to farming deer.
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It depends on life-span and breeding speed. (as well as "evolution speed" that might be different for aliens)
It is more question of generations. About 40 generations should make it.
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How would the human body be affected if the oxygen levels on Earth suddenly decreased by 15 percent? This is instant. Not over time. How would we adapt? Would some people die and some not?
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If you mean it we lose 15% of current concentrations, to %17.85 it will be harder to breath we will have a harder time concentrating and thinking. Many more people would need to be put on Oxygen to survive, many smokers and others with lung and blood issues would likely die before they knew what was wrong. Some of it might depend on what replaces that missing %3.15 if it disappears because of combustion and is replaced by CO2, while not immediately fatal, combined with the lower Oxygen content could be devastating to most animal life. The healthiest would likely be OK, and those living in very green areas, forests, crop fields etc would do better (assuming the sun is out and plants are doing their thing, if it was a large fire that caused it, there might be no sun for a while, so the plants would be sucking up Oxygen too).
if you mean total Oxygen drops to %6 then those without access to Oxygen masks are pretty much goners.
some useful info here.
<http://classroom.synonym.com/minimum-oxygen-concentration-human-breathing-15546.html>
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Denver has about 17% less oxygen than at sea level. Note that this isn't reduced *concentration*; there's just less air. This answer doesn't address the increased proportion of *other* elements in the air, only oxygen reduction.
According to [this article on altitude sickness](http://www.safety.com/articles/avoiding-high-altitude-illness), the first effect that kicks in from reduced oxygen is hyperventilation -- you breathe faster in an attempt to get more oxygen into your lungs. This can lead to weakness, dizziness, and fainting. More-severe symptoms can occur at higher altitudes (= lower oxygen levels), from vomiting and headaches to pulmonary edema and brain injury.
Obviously it's possible to acclimate -- people *live* in Denver, after all. So the main challenge seems to be the transition -- those first few days after the oxygen drops are going to be challenging. But people who avoid strenuous activity for a few days and take some extra care with diet and medications can adjust.
A sudden 15% drop is like everybody hopping a plane to Denver -- uncomfortable at first, but with care it's not likely to do long-term harm. Of course, people who are already medically fragile might suffer worse consequences.
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Humans routinely experience a loss of more than 15% of the available oxygen in a matter of minutes with no harm done. It's called flying in a plane.
Note, however, that it looks like there might be a relationship between long term lower oxygen levels and depression.
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Google "hypoxic air technology for fire prevention" for a lot of pertinent information.
If some oxygen in air at normal pressure is replaced by nitrogen, one effect is that fires become much harder or even impossible. It also reduces the rate at which paper oxidizes. This technology is therefore used in archives of valuable paper documents. Down to 13% oxygen or thereabouts there are no health problems caused in the very short term to healthy people entering the archive to retrieve documents, and desk-working in the archive for hours at a time is also not known to be harmful. You'll breathe faster to compensate but may well not notice. People with severe chronic respiratory diseases are affected adversely, as with flying or altitude.
In the longer term ( days to weeks) I would expect that acclimatisation takes place if one works in such an archive, just as it does if you travel to a higher altitude. The body makes more red blood cells, basically because each is carrying less oxygen. This can have adverse health implications, mostly small increases in risks of serious cardiovascular events.
One important point. If you are considering a low oxygen *planet* then that is a planet where intelligent life almost certainly never got past the stone age. This is because natural fires would scarcely exist and making fire by friction would probably be impossible. No fire, no metals. No metals, no higher technology. Probably.
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Only less than 6.25% of oxygen decrease will allow humans to live. Any less oxygen than this will not support human life. This decrease of oxygen will increase carbon dioxide content by 2500 times and that will increase atmospheric temperature by about about 125 degrees Fahrenheit, which is not suitable for human life.
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In this concept, a person is confined by a precisely-defined invisible barrier that causes extreme pain when any part of them crosses it. It affects only them, thus the source of the pain must be within them, but triggered externally. I'm thinking something like nano-sized GPS receivers (either organic/chemical or mechanical) that have been put into their body and have dispersed to all of their nerve receptors. When any part of their body crosses the threshhold of the GPS coordinates, the receivers do something to excite the relevant nerve receptors to an excruciating degree. I'd be curious to hear plausible ideas about nano/biological/biochemical systems that could produce spatially-determined effects within the human body.
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Ferrite nanocrystals dispersed in one's body, and a microwave source can do what you are looking for.
When the subject gets outside of the shadow area for the microwave source, the ferrite will start absorbing the microwave and convert them to heat, with related discomfort/pain.
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You can buy these things from Amazon. They are usually meant for pets. I find this to be a kind of animal cruelty, but if you apply it to a human, it might be something more humane than prison.
With pets, you use a set of transmitters to make an invisible fence. When the critter crosses them, their collar will give them a little jolt. With humans, all you need is to adapt the collar.
If you want something really fancy and you like DYI, you can instead take an electronic tag - the kind worn by people under house arrest - and combine it with a tazer. If you want to be cruel, you can make an implant, kinda like the internal part of a pacemaker.
Heck, I'm even gonna prototype one now and make a Kickstarter to sell it.
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## Camera and Laser
The invisible wall is defined via software. There is a camera with depth perception. Any part of the prisoner's body that touches the wall (as seen by the camera) is shot by the laser, which will hurt. The laser can even be outside the visible light spectrum. The software will not aim the laser at non-prisoners.
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I don't think nanotech is necessarily required when you could just **put a chip in the pain center of the brain.** From there, you could remotely activate it to cause the sensation of pain, modulate *exactly* how painful it is, and prevent it being solved by anaesthetics or narcotics. And since you already have a chip inside the brain, you could also add the failsafe option of inducing a seizure or unconsciousness remotely.
As far as the granularity of the zone is concerned: if you just want it to be "when crossing X point" then you could have the equivalent of an RFID chip or some sort of GPS signal and give it a bounding zone. I prefer the latter because then you could also set up a failsafe where if the GPS signal isn't detected for X period of time it starts inflicting pain, which would prevent blocking the signal with a tinfoil hat or what not.
If you want more granularity, a few well-placed sensors will allow an excellent amount of coverage. **Placing relay sensors in the T1/L4 vertebrae, elbows, hands, knees, and feet would be very effective in preventing any part of the body being extended past the zone** without the need for more comprehensive solutions. At that point, what could possibly get out of the zone? At most, some fingers or toes, and at that point just increase the size of the bounding box by six inches (and honestly another two feet just for good measure) and you're set.
This system could actually be relatively cost-effective, all things considered. The brain chip is obviously the main expense, but that's just a GPS/RFID chip and a simple way to stimulate the brain. Have a surgeon or robot install it and you're away. Then 11 relay chips that are just RFID/connect to the brain chip somehow, and RFID is cheap enough even with *today's* technology. Have a nurse or another robot install those (which are even easier to install), and that's that. Plus, this allows for easy removal of the system if the prisoner is released or if the plot demands it.
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If you can put implants in the target's body, and those implants either
* have long-lived batteries (weeks-months with current tech, dependent on the size of the battery pack)
* draw energy parasitically from the target's system (moderate-future tech, maybe 20-50 years?)
and the implants are large enough to have a GPS transceiver (think cell phone, though phones are dominated by the size & weight of the screen + battery),
then you can do [pretty much anything you want to the target](https://en.wikipedia.org/wiki/Physical_access). <10 mA across the appropriate nerves could probably cause excruciating pain and/or let you [manipulate the target like a puppet](https://en.wikipedia.org/wiki/Frog_galvanoscope)... depending on how good your surgical procedures are. Pain & spasms are going to be easier to do than fine motor control. No hardware required other than the implants and the existing GPS network.
If you can't put an implant in your target, you could ward specific areas with [directed energy weapons](https://phr.org/our-work/resources/health-impacts-of-crowd-control-weapons-directed-energy-devices/) and put facial recognition or other sensors in the area whose access you want to control. Turn on the system only when the target approaches. Of course, those systems may be vulnerable to both false-positives and false-negatives, and creative targets might try to cross at the same time as someone you don't want to fry.
More exotic, target-specific wards / pain-walls might become available further in the future by having swarms of nanites that look for genetic markers and restrict themselves to particular areas. They'd effectively be *infecting* your target if small enough to enter the body unnoticed, or *infesting* / *attacking* the target if a bit larger. But they could presumably induce all the pain & control options for implants above.
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We can kind of [do this today with millimeter waves](https://en.wikipedia.org/wiki/Active_Denial_System). This operates on a principle similar to a microwave oven, set to use a wavelength that completely and fully activates the pain receptors of any skin they hit, forcing a complete flight response. You do NOT want to be there.
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> For the first millisecond, it just felt like the skin was warming up. Then it got warmer and warmer and you felt like it was on fire. ... As soon as you're away from that beam your skin returns to normal and there is no pain.
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This has four major drawbacks based on the question, but I list it here because I feel like it's the most "sci-fi" solution, and depending on the exact details of the story it *might* still work:
1. They don't discriminate against the prisoner. You may be able to work around this if you can allow visitors and jailers to wear special clothes, or have other protections, especially if its something like fibers woven into normal-looking items so the prisoner might not perceive they're doing anything special. Combine this with things like disabling parts of an emitter array as people approach.
2. You can't put them everywhere. The barrier is only going to be so thick, and once through it the prisoner is completely free. You'd need to fill a fairly thick area to be effective.
3. They won't protect against something like tunneling. Even a piece of cardboard is enough to totally block the effect based on current capability. For a science fiction story, you might get by saying the captors use a different band or type of radiation that can penetrate solid materials to a much greater depth.
4. It can actually cause burning if the exposure lasts too long.
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Against my better judgment, I'm going to give you a tech that isn't here yet.
Nanobots, not even smart ones.
They spread to predetermined places where nerve traverses, sit dormant absorbing your body's energy and filling some kind with small capacitor, then when they detect your coordinates are outside boundaries, they release small pulses that would cause pain, discomfort and uncontrollable spasms, maybe even death, if you feel like it\*.
In reality, this would require a ammount of energy a single nanobot probably can't generate/contain
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I sadly couldn't find any answers to this question, probably because it's quite niche, so i'm posting this as my first question here!
The <https://en.wikipedia.org/wiki/HMS_Dreadnought_(1906)> was probably one of the most influential ships of its time, and pretty much paved the way for many of the design-elements which would shape modern Naval-warfare in the 20th century into what it was.
It's creation lead to a new class of battleship being created, the aptly named "Dreadnought."
The main characteristic of a Dreadnought was it's uniform Main-Battery, an "all-big-gun" design.
The ships built before, and made obsolete by the HMS Dreadnought became known as <https://en.wikipedia.org/wiki/Pre-dreadnought_battleship>, and unlike their successor, these ships mainly featured only a few medium guns, supported by a large array of smaller guns mounted to the ship's sides.
My question would be, what would need to happen in order for Pre-Dreadnoughts to stay the dominant form of Battleship well into the 20th century (possibly up until the 50's or 60's), and what would naval-warfare look like as a result of this change?
Side Note: The evolution of the aircraft in my setting has been stunted to the point where they effectively do not exist, so air-craft-carriers aren't really a factor in this question.
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**What is a Dreadnought all about?**
* All big gun batteries rather than two different 'large' calibers.
* Gradual improvements in armor materials and hull construction, which provided weight for the mounting of the big guns.
* Steam turbine propulsion, still coal-fired.
Why all big guns? So that they could fire in salvo, the best method of ranging then available. But big guns also had drawbacks. Bigger individual guns means fewer of them on the same displacement, and more constraints on where they are mounted. Battleship designers thought a lot about on-end fire, or broadsides, or even wing turrets firing across the deck. (Doing that would have damaged the firing ship, but a few decades earlier the plan was to throw masts overboard if there *might* be a battle ...)
So introduce improved [optical rangefinders](https://en.wikipedia.org/wiki/Coincidence_rangefinder) and [fire direction systems](https://en.wikipedia.org/wiki/Director_(military)) a few years early. That means the hit probability for individual guns goes up, even at long range, possibly resolving the need for many ranging shots. This might encourage the further development of ships with enormous guns in single turrets, the breech-loading successor of the [100-ton RML](https://en.wikipedia.org/wiki/100-ton_gun). The low rate of fire and low number of these main guns dictates the retention of slightly smaller guns, around 10", for use against anything short of an armoured cruiser. This gives both a "big wallop" against enemy battleships and a "deep magazine" against cruisers or shore emplacements.
There might be a school of thought to build ships with a *single* main turret, not two fore and aft, to allow even bigger guns under even more armor. This might also help with flotation and stability.
The turbine will probably come at some point, but you can delay it by commercial investment in efficient quadruple or [quintuple-expansion](https://en.wikipedia.org/wiki/Compound_steam_engine#Multiple-expansion) steam engines for big liners. Possibly there are early advocates of an [unit system](https://en.wikipedia.org/wiki/Unit_system_of_machinery) where each boiler can feed each cylinder.
**What happens to naval warfare?**
Possibly not much for the first couple of years. Capital ship actions would differ in detail, but there would still be steel behemoths lobbing shells at each other.
I've read it argued that *torpedo fire* was ineffective in the era, but *fear of torpedo fire* drove both design and tactics. At the [Battle of Jutland](https://en.wikipedia.org/wiki/Battle_of_Jutland), torpedoes hardly ever hit, and they were a fire hazard to the capital ships which did mount them. So you could have either *arrogant* or *realist* admirals dismiss the torpedo except for very special circumstances -- cheap and expendable coastal torpedo boats, and submarines which *might*, on a good day, maneuver into firing position against a slow merchant convoy. (Or enter a protected anchorage, but that is what booms and nets are for.)
As time goes on, it becomes harder and harder to envision what the lack of aircraft does. Will radar be developed, to further increase the hit probability for ever bigger guns?
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## Minimize the precision of big guns or the increase firepower of small guns
Smaller cannons are less effective against a heavy warship, but they can give you more opportunities to hit an enemy. Imagine you have 2 options: 1 cannon that hits REALLY hard or 4 cannons that can each be reloaded twice as fast. In theory the single big cannon can punch a hole clean through the other ship, possibly sinking it whereas the smaller cannons will only cause surface damage. So, you can do a lot more damage with a single big gun which is why the Dreadnaught became such an important class of ship, but if you can't fire precisely enough to range a target, then 8 shots that will probably miss can be a lot more helpful than 1 shot that will probably miss. This is why older ships-of-the-line used so many cannons. The main reason fewer, yet bigger guns became so effective is because once you ranged in on an enemy ship, they were precise enough to reliably hit. But if both guns are too imprecise to reliably hit once the enemy is accurately targeted, then having more opportunities to hit becomes more important than absolute stopping power.
Now let's consider a you have a dreadnaught with 24 big cannons facing off against a Ship-of-the-line with 96 of the smaller cannons, but thier cannons are only precise enough to have a 1% chance to hit at engagement range. The dreadnaught gets off its 24 shots, but only has a 21% chance of hitting the Ship-of-the-line. In contrast, the Ship-of-the-line gets off 192 shots giving it an 84% chance of landing at least 1 shot (1-4 hits is pretty likely). In our history, the dreadnaught could increase its odds to hit after its first shot by ranging the enemy ship, but if the cannons lack the precision to get this accuracy up by enough to matter, then the dreadnaught is likely to already be badly damaged by the time it lands its first hit.
## How to make Ships-of-the-Line stay superior:
* Make cannons less precise: This means that even once you range in on a distant target, your odds of hitting it go way down; so, it takes a lot more cannons to land a hit. Basically if your setting skips over certain improvements in gunpowder, shell, or barrel manufacturing processes, then your cannons may just not have WWI levels of precision.
* Effective optical glass is never invented: This limits cannons to distances where they can only be ranged with the naked eye. If you can't clearly see where your shots are landing, it could make intuitive salvos able to out reach a ranged shots.
* Better Gun Powder: If improvements in gunpowder mean that you are targeting a ship farther away because you have a faster mussel velocity, then you experience the same precision issues that you face with a less well made cannon.
* Better Shell design: If an 8" cannon can do as much damage in your setting as a 14" cannon did IRL, then you can not risk sailing into target accurate ranges because your are risking 1-hit 1-kill either way. Instead, the guy who can salvo you from farther away and land a single lucky hit will win.
* Worse Armor: If the ironclad is never invented (or invented much latter), then battleships will not be armored enough to survive hits from smaller cannons leading to the same result as better shell design.
* Honeycombed Hulls instead of heavy armor: If ship designs change to have a highly redundant honeycomb structure so that it takes a LOT of hits to sink regardless of shell size, then landing more hits becomes more important than landing strong hits.
* Most rival nations prefer large fleets of smaller ships: If the enemy does not have any heavy cruisers, then big guns are a waist of stopping power. Instead, you might opt for smaller guns so that you can engage more enemy ships at once.
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Submarines and torpedoes. Large ships were just bigger targets. No battleship would be able to defend itself against submarines. After WWI, battleship were seldom used in naval combat, they primary role was shore bombardment. Since WWII, we have not had any major naval battles. Modern submarines will be devastating against surface ships. Long range guided torpedoes and vertically launched cruse missiles will kill surfaces fleets. Even if the sub is detected and killed after launching the attack they will still kill many times their numbers before dying.
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### The exact same, because Dreadnaughts were the only logical way battleships could have developed.
Remember, Dreadnaught wasn't the first concept of an "all big gun" battleship. The Japanese <https://en.wikipedia.org/wiki/Satsuma-class_battleship>, that launched a year earlier, was designed with an all big gun armament, but the Japanese couldn't scrape together enough 12 inch guns, so they were forced to replace some of them with 10 inch. If they had enough resources, the type would have been called "satsumas", not "dreadnaughts". It still had VTE engines, not turbines, but turbines are a "nice to have", not a "must have". The German Helgoland-class and Nassau-class were still dreadnaughts.
Why was the concept of "all big gun" inevitable? Improvements in range finders and fire control, permitting engagement at much longer ranges.
Ship's guns could technically fire to the horizon(with enough elevation) even in the 19th century. The chances of hitting anything were negligible, so they weren't even given that elevation, because it was pointless.
For context, during the battle of Manilla Bay, only 8 years before the launch of Dreadnaught, but before the revolution in range-finding and fire-control, at an engagement range of 2000-5000 yards(~1-3 miles), [US ships had 170 hits for 5,859 shells expended and the Spanish were even worse](https://www.history.navy.mil/about-us/leadership/director/directors-corner/h-grams/h-gram-018/h-018-5.html).
Once the capability to hit something remotely close to what you were aiming for 10+ miles away existed, all big guns were **inevitable**: Before, it was a tradeoff between firing lots of smaller shells(smaller guns could range out as far, even an 8 inch cruiser gun is ultra-heavy artillery on land and 6inch is the standard 155mm heavy field artillery), or a few big ones, with the same effective range, that where you had a chance of hitting a moving target from a moving platform. At longer ranges, smaller guns could not effectively fire faster than big ones, because the firing ship still had to wait for the shells of a [salvo](https://en.wikipedia.org/wiki/Salvo) to arrive, see the splashes of them hitting the water(the first salvo was expected to be a miss, but in the area), correct your estimate, fire again, correct, etc. until you start hitting.
[Here are the flight times of a typical 12 inch gun of the period](http://www.navweaps.com/Weapons/WNUS_12-50_mk8.php):
[](https://i.stack.imgur.com/iRk7U.png)
As you can see, at a range of 10 miles(what most of the actions at the battle of Jutland were fought at), flight time is ~30s. If you add the time to observe
the splashes, correct aiming solution and fire again, you're looking at a maximum of one round/40s, **no matter the caliber** and it becomes a no-brainer to mount all big guns.
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Rather than those brash big gun battleships, methinks the high seas would remain the dominion of the stately pre-dreadnoughts, with their dashing good looks and mixed armaments. Dash it all, combat would be a more intimate affair, ships grappling at close quarters like gentlemen, exchanging blows from their secondary batteries! Not at all like these newfangled duels at long range.
Why, without the tremendous pressure of the HMS Dreadnought, the naval arms race may have been more of a leisurely stroll! The powers would build their pre-dreadnought squadrons at a more reasonable pace, I dare say. And technology would evolve at a gradual clip, not this relentless headlong dash into untested waters those dratted turbines caused.
Tactics and training would be geared more towards torpedo maneuvers and rapid fire gunnery at shorter range. And blockade duty would require a deft touch and nerves of steel to face the dastardly threat of torpedo boats in confined waters. Not at all suitable for those long-in-the-tooth pre-dreadnought captains grown accustomed to partir in style!
Warfare on the high seas would have been a more gentlemanly affair without those confounded dreadnoughts. Their immense firepower utterly transformed naval combat, though some say not for the better. Alas, we shall never know what heights the venerable pre-dreadnoughts may have reached if only left to their own devices.
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Torpedoes rule the waves.
If we assume some collective black box on thinking about putting big gun on ships, we end up with very, very tanky ships shrugging off shots for maybe days.
But people would still be looking for a way so their ships would actually manage to sink the enemy. The solution (before air power): torpedoes. A big capital ship may shrug off medium cannon balls, but a big torpedo is a very different matter. And with the reduced range of naval combat evading them would be a lot harder.
We would probably see a reduction in almost useless deck guns, replaced with ever more torpedo launchers. Probably also a reduction in ship sizes, until a equilibrium is found between large enough for armor to shrug the small shots, and small enough to not loose to much when a torpedo sinks it
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No improvements in ranging/firecontrol/sensors. So no optical rangefinders, fire control directors or radar.
Without any of these tools, battleships are limited to the abilities of turret crews to aim directly, limiting engagement ranges. At these limited engagement ranges of per-dreadnought battleships any large shell will penetrate if it hits. But without the ability to reliably hit what matters is rate of fire, to maximize your chance of seeing any hits, and to get those hits in before your opponent gets there lucky hit.
In this scenario, I expect we would see larger ships in order to mount more guns, with subdivision to allow them to keep going even as they take penetrating hits in other sections, along with more barrels per turret (triple or even quad turrets if they can be made reliable), along with more automation in the shell handling and loading systems to maximise rate of fire, especially during the initial exchange of fire.
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In my setting I have a species of anthropomorphs (basically humans) that grow from baby to full-size in the shortest time period possible. The babies are the size of human babies. How short can that time period get, and what modifications should their body/genetic material have to grow at an incredibly fast pace?
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I could name a few factors.
Some species with short lifespans might be forced to procreate at a younger age and spread their genes as quick as possible before getting eaten by predators. Which means that females will be forced to give birth at a much younger age. Over a long period of time natural selection will cause males to pick females who are the most fertile. The females who become fertile the quickest will be able to pick the best genes from all the males.
This will cause gene mutations in both males and females of your species to reach puberty and adulthood at a much faster rate.
Other factors are hormones. Providing higher levels of Human growth hormone , estrogen and testosterone can accelerate the the growth rate of your antropomorphs/humans aswell.
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An example of another animal of similar body mass to humans is a cougar (puma, mountain lion). These reach maturity in two or three years.'
***HOWEVER*** the puma's brain development is not comparable to that of humans. More similar animals, like chimpanzees and orangutans, take ten-plus years to mature because, more similarly to humans, their brains require significant maturation after birth. Not to say that a cougar's or wolf's brain doesn't change and mature after birth -- but they are less helpless when born and don't need to reach the level of mental maturity a human or great ape does.
Physical maturity, then, might be possible in less than five years, perhaps as little as three (learning to walk upright is more complex than learning to walk on all fours, for instance, and doing so requires more growth in the legs, spine, and related musculature), but mental maturity (given similar final mental condition) seems unlikely to be completed in less than fifteen to twenty years, as is the case now.
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You can grow an adult *body* within a couple of years, compare to animals, but you cannot grow an adult brain that fast, your adults would be immature emotionally and intellectually.
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*Adult* is kind of iffy here, because it is possible to grow to full size significantly before reaching mental maturity. This happens in a lot of animals, though obviously the most familiar example is [dogs](https://www.hillspet.com/dog-care/behavior-appearance/when-does-a-puppy-become-a-dog?lightboxfired=true#) üêï.
I am going to assume you meant full-size from context.
Humans grow unusually (and kind of pointlessly) slowly. For comparison a [beef cattle](https://a-z-animals.com/blog/cow-lifespan-how-long-do-cows-live/) üêÑ only *live* 2-3 years.
Humans would almost certainly reduce full-size time down to 3 years or younger eventually with enough survival, just because it gives a **massive** inherent advantage in education üè´ and training, making life easier and increasing effective intelligence. So anthropomorphs could have just been around for a long time.
As for further increases in speed, the easiest way is to just grow cells outside the body and inject them in. This could be their own, or you could make them feeder cells grown. Maybe in a plant-esq thing. This is far quicker than digestion.
As for other measures, maybe having a cartilage proto skeleton before the bone one.
Kind of hard to predict those effects, as no animal has that growth strategy, mostly because civilisation to support it has not been around long enough to develop it.
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So, in all, 3 years or lower is easy naturally, if other measures are employed, it will be a lot faster, but very hard to predict a limit.
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There is substantial variation within existing humans on the age vs height for children. I have shown only the first graph from [here.](https://tall.life/growth-chart-child-boys-girls/)
Note that the lines on this graph may be misleading. A baby born "on" one of these lines does not necessarily stay there. These are the percentile lines so, by definition, they go up as they do. A child might move from one line to another, growing faster or slower than their cohort.
You could get a substantial start by determining the factors that produce this range. There will very likely be genetic factors. There will also very likely be factors of diet.
So, if there were some factor that required babies to grow quickly, a species might rather quickly evolve to match. Maybe there is a predator that only takes prey under a certain size. Or maybe there is a harsh winter such that smaller people tend to freeze. Those with genetics to grow quickly, and who live in cultures where the right kind of food is provided for them to grow, will suddenly be tall. The ones that don't will tend to die out.
[](https://i.stack.imgur.com/h99eU.jpg)
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In my world, there is a civilization with about 1800's-level technology. There is a nuclear accident in part of the world that they need to access. Is there a way for a civilization with this level of technology to protect themselves from radiation(even for a very short time?)
Edit for clarity: The main radiation that they are avoiding is nuclear fallout, and they are fully aware of the danger that it poses(due to the fact that no plants grow there and all animals that visit die)
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Human had Plumbum (Lead) for thousands of years, which can shield human body from most forms of radiation. The problem is knowing where to apply shielding:
With regards to isotope poisoning: test unknown foods before consuming, by using materials which discolor in presence of radiation or organisms which will die of exposure. AFAIK, radiation will turn iron in meat from red oxidation state to brown and then green so the green tint on exposed meat may be used as a sign. Maybe some kinds of mold or moss particles may be used as indicator?
In case of radioactive fallout: Knowing the dangerous areas and avoiding venturing from paths there, since there may be fallout on the ground for a long time.
With regards to actual nuclear explosion sites: avoiding these.
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You can't protect yourself from a danger you are not aware of.
1800's-level technology was totally ignorant of the risks related to radioactivity. Marie Curie (born 7 November 1867 – dead 4 July 1934), while researching on radium, used no protections against it, resulting in her notebooks being still radioactive today, and her coffin being lined with lead.
That's the level of awareness you can expect: they will be happily visiting the incident site by just wearing cotton or wool clothes, breathing openly and not caring about the dust. Maybe they will be even attracted by some nicely shiny material and take it home as souvenir, like it happened in the [Goiania accident](https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident).
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If they are aware of the problem but don't have the technology, they can just follow the guidelines we have today for civilians, for survival after a nuclear war.
Unless you have a high-tech bunker, you can't protect yourself from all the fallout. But you can reduce it, by focusing on the most important thing: **keep dust away.**
There is nothing you can do against gamma radiation. For all other types, you can reduce the risk by staying inside and leaving the house only if you must, and by thorough washing whenever you go back inside. Dig up the land around your house and reverse it, so the layer which was on top before, gets below ground.
If the general population learns one thing: "dust is poisonous", it can help a lot in reducing the casualties. There will still be a lot of casualties, but keeping your surroundings dust-free and being careful to keep as much dust out of the homes as possible, will help reducing them.
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Detection is a form of protection. Knowing where the radiation is a big part of the problem.
The Leyden jar was invented around 1745 and is an example the early investigations of electricity so that fits in with your time period.
The gold leaves of the jar separate when charged up, (like charges repel) and when radiation enters the air in the jar, it ionizes it, creating both positive and negative charges. The mobile negative charges neutralize some of the charge on the gold leaves and this results in the leaves coming closer together. This is the principle behind the electrostatic dosimeter. The wikipedia page shows these can be quite compact and sensitive. [Quartz Fiber Dosimeter](https://en.wikipedia.org/wiki/Quartz_fiber_dosimeter)
Radiation can also discolor glass, the color depending on the impurities in the glass. So perhaps depending on how far you want to stretch the science that could serve as a warning.
Similarly there are crystals where the radiation excites an electron, and the electron is trapped, until the crystal is heated. When heated the electrons de-excite emitting a photon. These are called thermoluminescence, and the amount of light is proportional to the amount of radiation.
In terms of protection, different materials have different 10th thicknesses, or half layer values. Lead being very dense would reduce the radiation by a 10th or a half with thinner layer than a less dense material. This is true for gamma rays and neutrons. Water for example is pretty good at slowing down neutrons, and can be a form of shielding for gamma rays too, although it is not as dense as lead.
But there are also different types of radiation, alpha particles, beta particles, gamma rays and neutrons, and the type of shielding would depend on the radiation type. Alpha emitters are pretty harmless, unless ingested. Beta particles are also blocked very easily.
People are pretty smart, If in your era, people are starting to mess around with photography, then they could discover x-rays, or other forms of radiation. The first photograph was around 1826.
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Armor made from or coated in lead would help, but only against some forms of radiation (Alpha and Beta particles), but not against others (Gamma rays) You would have to be careful that the radioactive substance does not release gamma rays, or else have it sealed in a vault with several inches of lead surrounding it or base your civilization in a castle-like structure with lead or other heavy metal walls. A castle with gold-composite walls would be super cool, although it would have to be mixed with other metals to be structurally sound. That would probably be my choice: Gold walls and Gold-plated armor when you have to go from place to place. This would do really interesting things with the value of gold, gold mines would become the point over which wars would arise, people would try to scrape gold of others castle walls, etc. Though as pointed out, there would have to be an in-world explanation for why they know about the gold. You could also have alchemy be a really big, heroic thing to do, trying to create gold for the defense of the kingdom. There is really a lot of cool things you can do here.
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Suppose a unicorn agreed to let a person ride/tame it for combat in battles, and assuming as a baseline, without any magic assistance, that the horn is made of a similar material to ivory, in the shape of a spiral, with a size range being a minimum of 12 inches and a maximum of 28 inches, how effective would its horn be in said frays? Particularly stabbing or lunging with the horn.
Edit: To add some clarification on what I mean when I say "combat" it as a baseline is against a small group of people that contains individuals both on and off horseback.
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Not very in most circumstances.
Assuming a unicorn is is all other aspects (size, agility, endurance etc) identical to the average war horse and also assuming a pre-gunpowder setting I see the following problems;
Although the horn might be useful in and of itself an in a 'one on one' combat between two lone opponents where one is riding a normal horse (and the unicorn gets a chance to stab the other mount or rider) it will be of little use in *massed* combat.
Firstly just like a horse a unicorn has to get within range to use its horn and that means would it have to charge through missile range to get to the opposition. And since its just as vulnerable as any normal horse it will suffer similar losses doing so. (Remember also that in massed warfare the target is *not* any *one* horse or soldier. If you have 1000 horse in a formation (say 200 wide by 5 deep) charging 1000 archers (the same) each archer's target is **one big mass of flesh** that just happens to be 200 horses wide and 5 deep. Also generally the target was the horse not the man because well, the horse was bigger!
Then after you close to the enemy the reach of the horn is still less than that of your average armed opponent on horse or foot. Any pike/lance, pole arm, sword or mace etc has longer reach than the horn and again as far as the enemy is concerned the target is any unicorn within reach, so the first couple of ranks of spearmen for instance all have the choice of say 2 or 3 targets not just the unicorn immediately in front of them. And of course any three men can attack one horse if they chose.
Finally if they are identical to horses in all other ways then unicorns are not suicidal either and (unlike what you see in the movies) horses were historically *not* willing to charge blindly onto the end of a spear tip if they could at all avoid it! Which means they to would try to stay out of range of all those sharp pointy/stabbing things. Which of course again eliminates their horn as a option.
Where they *might* have an advantage would be in a more flowing, 'open' style of combat between small groups (think as an example skirmishes between the 'plain peoples' of 17th & 18th century North America) where a charging unicorn might be able to lower its head and take out an opponent if given the chance. Although again I assume the other side would soon learn to be wary of this tactic and would try to adapt.
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## They could easily be more of a detriment than a benefit
To prove this point, let's assume the best possible scenario for the materiel properties on that unicorn. We will say that it is hard and sharp enough to punch through armor and that the unicorn's skull and neck are properly reinforced to survive an impact at full charge.
Now let's compare that horn to the unicorn's other main natural weapon: its hooves. Horses are heavy, and when they impact an infantry formation at speed, only a small amount of the horse's inertia is required to punch a lance through an enemy's armor assuming you connect well enough to not just glance off... but all the rest of that energy could go into trampling enemy infantry. Because of the horse's size, each foot step the horse makes is like getting hit by a giant mace with enough energy to reliably maim or kill through armor, and a horse can have enough inertia to trample through several lines of infantry. In the Early Medieval period before long spears came back into fashion, when heavily cavalry would charge an infantry formation, the most important factor for success was having enough momentum to trample though the enemy formation and come out the other side. So, while the rider might take out 1 enemy with a spear, the horse might take out 4-5. For this reason, many cavalry though out history have actually preferred cutting swords like a spatha, saber, or falchion over spears so that they too harm multiple enemies on a single pass-by.
If you put a horn on the unicorn, it means that the first person you hit will get stuck on the front of the unicorn blinding it, weighing it down, and possibly still being alive long enough to have easy access to slit the unicorn's neck as you carry him along. Unlike a lance the unicorn can not just let go of his horn when it gets bound up in an enemy and keep moving. So, as a one-use weapon that only marginally improves reach, its ability to interfere with its multi-use weapons would make it worse than not having it.
**How to make the horn a useful weapon?**
First, it needs to be longer. The average cavalry spear (lance) throughout history was about 3 meters long which could reach about 1.5-2 meters in front of the horse. The lance would not necessarily do a ton of killing, but it could help break up the first line of infantry and press them back into the enemy formation enough to make defending against the trample much harder. So if your unicorn horns were about 3 times as long, they might be able to match the effectiveness of a lance.
Secondly, your unicorn needs to be able to "drop" it. Some animals have body parts that break off by design. Bee stingers, skink tails, etc. So, if you make it so that the horns are strong enough to impart significant energy, but them break off so they don't get stuck, then you could further replicate the utility of a lance.
The problem still exists that unicorns can not just recover thier horns after a battle, but may instead need to spend months or even years regrowing them; so, they are still not as good as a lance in this respect, but probably still good enough to be considered "useful".
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During the London Bridge terrorist attack, a narwhal tusk was taken from a display case and used as a weapon against the terrorist. This is pretty similar to a Unicorn horn.
<https://www.bbc.co.uk/news/uk-50870309.amp>
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Pretty useless.
A horse is not designed to charge head-first and head-down into things, regardless of whether the horse has a horn or not.
The horn will break or the unicorn will snap its own neck or both.
Even if the unicorn survives the initial impact he/she will at least be groggy or dazed from the blow and easily dealt with by the opposition.
It's a one-time use thing and will be pretty close to suicidal for the unicorn. I can see it happening as a last-resort option in a desperate situation, but not as anything that is usable/trainable for a real practical combat situation.
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The mythological descriptions of unicorns vary somewhat between two different, yet similar themes. The similarities are that in both depictions, unicorns have a gracile, horse-like body plan with a roughly one to two metre long ivory horn projecting perpendicular to the head from between and just above the eyes. The differences are that some legends depict unicorns as being small, roughly human-sized creatures, while other legends depict horse-sized creatures.
Another point in the mythological depictions of unicorns is that they are very strong, easily capable of carrying a rider (even the small type) at a rapid pace. They were also said to be an even match for a lion in combat.
Finally, Narwhal tusks were thought in medieval Europe to be unicorn horns, so we can assume that unicorns will have horns with similar properties.
So... horses are cursorial mammals, adapted to running quickly, though due to these adaptations, they do not achieve their maximum speed particularly quickly, nor can they turn quickly in comparison to other animals which are adapted to using their horns as weapons against predators.
If we compare a horse with a horn-wielding herbivore which uses its horns in self defense - say, a *Triceratops* - we can see if we put the two animals on the same scale, that the Triceratops is far more robust and muscular than the horse, to allow it to lunge and turn rapidly.
So... naively, it would *seem* that unicorns, following a horse-like body plan, would not be particularly capable at lunging with their horns, that their horns (if they are as magical as they are said to be) are of use mainly as instruments of healing, not harming.
However, given that unicorns are said to be very strong, either their gracile, horse-like body plan is rather more robust than the legends suggest, or they are *magically* strong. While this strength *may* be used for the mythical purpose of carrying maidens for whatever purpose, it is also just the trait required to make them effective at lunging with their long, straight horns.
Of course, if unicorns are small, carrying a rider would effectively double the weight of their bodies, making them far less capable of lunging effectively (just try jumping while carrying another person your own weight). On the other hand, a rider may be around only a tenth of the weight of a horse or a large unicorn, and would hinder the unicorn's lunge far less. From the OP's description, this is probably the type of unicorn in question.
So... these cavalry unicorns would be capable of lunging effectively even while carrying a rider, and quite possibly while also wearing steel plate barding. Their horns, like the tusks of narwhals, should be strong enough to be used as spears, as narwhal horns have been done historically.
That the horns of the OP's unicorns are 12 to 28 inches (0.3 to 0.65m) long makes only a little difference... a sharp-pointed horn backed by the better part of three-quarters of a ton of muscle and bone should easily be able to punch a hole through medieval plate armour, and would inconvenience even a person in modern kevlar armour. Similar to a fencer, a lunge of 0.3 to 1 metre would be quite sufficient to inflict a fatal injury to an opponent, where a penetration of the chest cavity of under 0.1m could easily be fatal to a human.
Armouring a unicorn would make it quite a formidable opponent on the field of battle, though even medieval plate barding left significant amounts of the horse unprotected.
So, my conclusion is that yes, a unicorn could (given the assumptions I've stated here) be an effective combat-capable mount upon a medieval human battlefield.
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All-in-all, this is your story in your world. Make these unicorns into your unicorns.
In a fantasy world with unicorns, as a player or reader, I would expect a fantasy *element* to unicorns. I would expect something that makes them very different from a horse with a horn. They must not be OP if you're putting them into a battle, (unless the point is for them to be the narrative cavalry that saves the day when all hope is lost).
My point is, I wouldn't be interested in a playing with or reading about a "realistic" unicorn that was defined on Stack Exchange. If I'm in your world, that's because its the world that you made, not because it's a world that closely matches realism. We like having some threads to reality that make things accessible and familiar, but we love the fantasy.
We want a wizard that studied weather control and can call down lighting. She may have to punch someone, but that mechanic isn't really a core aspect of the wizard. She can be a powerhouse and knock someone's teeth out, or she can be normal, or she can be frail and break her hand in the process. The story controls the mechanics. We want unicorns that can heal, or maybe if their horn is broken off, the unicorn becomes an untethered bolt of chaotic energy.
If your world doesn't have established "unicorn rules" that your players/readers would expect to be followed, this is a place where the "baseline" can be mostly irrelevant. I'm not saying "it's pointless", I'm saying don't sweat it. You can make that any mechanic that fits the story. Maybe just take whatever you use for a spear and give this creature approximately the same capability. But as a consumer of this story, I would feel a little jilted if the unicorn's most significant contribution is being a horse with a horn. And if this universe has unicorns that aren't magical/special, then I still think you're the best person to decide what that unicorn is.
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## **A unicorn ridden by a person is the most powerful weapon in your universe.**
*Note: I assume we're talking about a mer-person rider since they are most common and "humans" do not exist as such in this universe*
Since assailants can not look directly at the mer-person (because of their tardis-perception-filter-like properties) they are difficult to even acknowledge as an adversary. Also, the time-skipping movement of the unicorn makes them extremely agile as well as hard to target or understand where precisely they are going. The combined charismatic influence of the two would turn some immediately into loyal followers (almost worshiped), but even the ones that aren't fully affected would be unable to consider the pair as a traditional "enemy". Since the touch of mer-people can make an animal invulnerable to wood, metal or stone, and the breath of the unicorn can make itself and its rider become ethereal at will, most weapons are useless against this duo! Additionally, they are equally effective units traveling on land, through water or even into the skies (assuming of course that the unicorn is shod with the standard hard-light shoes that are common in this setting)
**OR** it's possible that none of this fits into your universe and you could make up literally anything.
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Deep in space a colony ship continues to accelerate unaware of the volley of railgun rounds hurtling towards it. As the light from the attack reaches the bridge the PDCs (Point defense cannons) are brought online and set to intercept the rounds. Unfortunately the ship is so massive and has accelerated so much that dodging or turning is not a option.
The 10 PDCs are 12 barreled caseless kinetic cannons firing 2mm composite slugs and nano disassembly rounds at a 12:1 ratio at a rate of 400 rounds per second and a muzzle velocity of 1000fps.
The railgun rounds are coming in at 2000fps every 20s for a total of 16 rounds. They are 2.5 pounds of titanium and mix of dense metals.
Assuming all the PDCs can be brought to bear can the cannons defend the ship? Defense means no rounds hit the ship.
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**You leave out a critical variable: distance at time of detection.**
Suppose I am an ass. I have an old tennis ball and I am going to throw it at your head because I think people will like me if I do. Can you catch it before it hits your head, and then the people will like you instead? You are not a ninja but you are blessed with inborn ninja-like skills.
The first time I am 30 yards away. You see the ball coming. You catch the ball with ease and nod knowingly.
The next time I am 5 feet away. The ball is so close by the time you see it that there is no time for you to catch it and it bounces off your head. Hilarity ensues!
So too your railguns. If your ship sees incoming railgun rounds two miles (~10,000 feet) out (this is space, and it is not hazy!) you have over 4 seconds and so thousands of bullets to send at it. If you detect the incoming projectile 500 feet out it is going to hit you before you can hit it.
How early can you detect these railgun rounds? That determines the time you have and the time you have determines the likelihood of an effective defense.
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I did some quick math; Assuming that the weight of the slugs is negligible the impact of a slug against a railgun round would have around ~4.7 $\times$ 105 joules (1.13 kilograms moving at a relative speed of 914 m/s and a lot of rounding on the browser console). That's about 0.13 kWh, which according to [my favorite table ever](https://en.wikipedia.org/wiki/TNT_equivalent#Examples), is about 10% of what you need to obliterate a small vehicle in a laboratory.
If we assume a small vehicle weights around a metric ton, then we are speaking about total obliteration for something that weights 2.5 pounds (which is about 1.13 kg).
The problem that you have is that once you get to this level of destruction, you are not deflecting the incoming projectiles anymore. You are pulverizing them. They will still hit you - they will just be clouds of small bits instead of whole rounds.
The armor of the ship might be able to take this since the energy of a round will be spread over a much larger area (and a lot of it will miss). But if you just can't be touched by those rounds at all, then yes, it's a loss.
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Better solution than the PDCs...
* Go down to the colony nursery and grab all the sand that can be spared.
* Throw it out the rear hatch such that it disperses in your wake.
* Wait for the railgun projectiles to hit your newly created micro-asteroid field at relativistic speeds.
* Watch the fireworks from your now safe ship.
* Use the PDCs on any projectiles which somehow get through the sand.
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Depends on the rest of your setting.
**If** a PDC hits one of the incoming railgun projectiles with at least one round (never mind nano or composite, mass matters here), it will impart **some** kinetic energy on the railgun projectile. That KE will change the course of the projectile.
That course change **may or may not** be enough to make the projectile miss. That depends in part on the size of your target, but also on how far out the hit takes place. And that, in turn, depends on sensors and targeting accuracy.
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The story: in a fantasy iron age world, a T-Rex-like animal (actually more like the size of allosaurus) has emerged from the forest and started killing people. The animal always retreats to the forest after making a kill, and it never strikes in the same place twice, which makes hunting it difficult. Because it's considered too dangerous to kill it head-on, a group of forest rangers decides to create a trap to kill it. The trap has to be placed deep in the forest to catch the animal off-guard, because it becomes very careful as it gets close to human settlements. The trap also has to leave as little trace as possible (scent or otherwise) so that the animal isn't deterred from approaching the trap. What kind of trap or approach would work best in this situation?
[](https://i.stack.imgur.com/v2trH.jpg)
Aside from the traits described above, the animal has the characteristics of a tiger: it's solitary, would take its prey to the forest to eat later, somewhat good at climbing trees (the forest has really big trees), and is very sneaky. It usually lives in deep forests with heavy vegetation and eats forest animals as large as itself, but this one for some reason have a taste for people. It's as intelligent as a chimpanzee, can remember human faces, and can recognize that some humans are more dangerous than others (it's a point in the story that a character tries to kill it head-on but fails, and then the animal persistently chases him because it recognizes him as a threat, but also recognizes that he has lost his weapons and is currently helpless).
I realize that the obvious answer might be "use a trap for tigers but bigger", so please explain about the details and obstacles of using such trap so I can better incorporate it into the story.
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A big hole in the ground with fabric and leaves on top sounds reasonable. Given how big it would have to be, there might be need for a wooden structure that would be weak enough to collapse under the T-rex's weight but strong enough so smaller animals don't trigger it.
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Lace a dead animal with poison, leave it in an area for the *T. rex* to find, it eats the poisoned animal and dies. A large carnivore like that isn't going to pass up a free meal. This is how people deal/have dealt with intelligent, large predators like wolves and coyotes even today. And if it can work on a coyote, which have a good sense of smell and are known to be canny, it can work on a *T. rex*.
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Traditional traps have had the same designs for thousands of years:
<https://www.livescience.com/39900-ancient-leopard-traps-discovered-israel.html>
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> "They look like a pile of stones, like a cairn, and you need a good eye and also some digging around to realize what it is," Porat told LiveScience.
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The problem is scaling the device. While a pile or rocks (or a wooden structure) that can trap a leopard isn't much of a problem, the idea of building a trap sized for an Allosaur (or T-Rex) is going to simply create too much of a disturbance and alert anything in the vicinity.
So instead of a trap or hole in the ground (same issue), you will need to do something like a tree drop.
The lure is still a piece of tasty meat, but grabbing the lure releases the trigger and causes something like this to swing out from the trees and strike the target:
[](https://i.stack.imgur.com/mLo6V.jpg)
If the target is very large, then a massive deadfall trap might be required:
[](https://i.stack.imgur.com/YKRff.jpg)
[](https://i.stack.imgur.com/kgwwF.jpg)
*What the deadfall trap might look like*
A tree trunk would deliver a blow of several thousand pounds to several tons across the neck or back of the creature, likely being more than sufficient to deliver a killing blow.
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If you have enough patience, you can totally catch it within 2-4 years.
Start feeding cattle brains to some of your cattle. Watch until they start showing signs of scrapies, a.k.a. mad cow disease. Once you get some scrapies-ridden cattle, feed their brains to more cattle.
Now simply release those cattle in the wild. The creature will likely feel lucky for finding such easy prey and will feast upon them. *Voilá*, you've got a T-Rex like creature whose brain is degenerating by the moment. All you need now is a search party - if you don't find it dead, at least it won't be able to flee or defend itself.
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First, pattern locking is required—examine different attack sites to figure out the pattern. If it was a creature it must have a pattern of which it attacks. Depending on the setting, this first step may require hundreds of people carefully planning and calculating or a single computer running a neural network-based prediction algorithm.
Once elucidated, the hunters would need to go to the exact predicted next attack, and set up a trap there.
It’s better to set up multiple traps at the most likely locations of the next attack to be sure.
Set up as powerful a trap as you can— drop traps with sharpened stakes at the bottom, with covers that flips so the beast can’t escape once in. Oil in the trap and torches to light the beast on fire and cook it from outside in once the beast fell into the trap. The details depend on how you want to write your story. No kill is overkill.
Depend on your purpose, and whether you want to keep the animal once killed (since you have specified that the primary purpose is to kill the beast), the details of the trap may vary, but the end is just to plan carefully beforehand and use as powerful a trap as possible for your hunters, so that the first shot would succeed.
Subsequent attempts at trapping the animal may be difficult, should the animal escape the first attempt.
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There is a saying in Chinese called, [‘Playing the pig, to eat the tiger’](https://zolimacitymag.com/pop-cantonese-word-of-the-month-%E6%89%AE%E8%B1%AC%E9%A3%9F%E8%99%8E-playing-the-pig-eating-the-tiger/).
It is about acting weak, to swallow the stronger force.
In this case, it may be very applicable.
You can have a physically ‘weaker’ human, a non-hunter, pose as the pig. That, or a very strong hunter, acting ‘helpless’.
The ‘tiger’ would sense their weakness and attack, trusting their judgement and instincts, lowering their guard.
By making use of the ‘tiger’s’ indiscretion, the ‘pig’ can then mortally wound/injure the tiger. The ‘pig’ would probably have to use a strong paralytic poison on the ‘tiger’, as considering its large size, a normal poison may not kill it fast enough. The ‘pig’ could use blow darts or throwing devices to apply the poison at a reasonable distance.
As soon as they apply the poison, they can fire a signal and make use of a pre-dug escape pit in the ground to escape immediate harm, leaving the paralyzed tiger for a team of nearby hunters to swallow.
As to who would be the pig, it would probably be a brave volunteer, looking for revenge for their family. They would have to be nimble and extremely perceptive, but not give off any dangerous ‘scent’.
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Would they be able to even destroy the nanoscopic machines, or would something like an EMP be much more efficient?
The nanites in my setting are programmed to tear apart the human genome of enemy troops. This effectively would mean instant death to anyone they managed to infest.
They have mannerisms similar to a swarm of locusts, like a black cloud of death.
Lots of the technology in my setting uses benevolent nanotech, which would also be affected by an EMP if it was in range of the explosion. Self building skyscrapers, and roadways are just the tip of the iceberg.
The best real-life comparison to the way the nanites affect human DNA is similar to how the amanita bisporegia mushroom affects anything that consumes it. It produces an amatoxin that inhibits the effects of RNA polymerase, essentially stopping transcription of DNA to the various RNAs that are essential for life. Essentially if the DNA simply disappeared from the body, the person would immediately feel the effects such as dizziness, followed by a period of a false recovery. In reality, this false recovery is just the cells accumulating irreparable damage.
After that, tons of horrible symptoms would take place, starting with symptoms like diarrhea, (Since the intestines have ceased to function) nausea, vomiting, and eventually massive organ failure as the vast majority of your cells die almost simultaneously. No amount of medical care could save you from this, unless it was of a magical or divine nature.
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*Are* they nanoscopic? teeny tiny things have a real problem getting around. They certainly won't swarm and fly like locusts; air viscosity at that scale is too high. They'd be blown around, and work more like fatal hay fever than a homing cloud of doom.
Anyway.
Yes, the nuke would work jolly well, *if it was close enough*. Nanoscale systems have problems shedding heat, so a nuke going off close enough will thoroughly toast them. Without knowing more about your nanomechanisms, I can't tell you how much heat is needed to kill them.
You can have a play with [NUKEMAP](https://nuclearsecrecy.com/nukemap/?&kt=20&lat=51.50972&lng=-0.59306&hob_opt=2&hob_psi=5&hob_ft=100&fireball=0&psi=&therm=_3rd-100,_1st-50,35&zm=13), a handy tool, which has useful things under its "advanced options" like "*Thermal radiation radius (1st degree burns (50%))*" which corresponds to a thermal irradiation of 10.46 joules per cm2. That's enough heat to toast the nanoscale replicators that make up the outside layer of *your* body, at least. For the example 20kt blast I linked, everything within about 4.16km of ground zero will receive at least this much heat.
Nuclear radiation (mostly gamma rays, I suspect, and maybe some neutrons) will also be highly effective, but its range is a) shorter and b) harder to work out the effects of. [Neutron bombs](https://en.wikipedia.org/wiki/Neutron_bomb) will produce less thermal radiation, but at close ranges the intense neutron flux should effectively neutralise nanomechanisms even behind cover that would protect them from merely thermal effects. A 1kt neutron bomb should be effective out to 900m or so, with range sharply reducing against targets in harder cover (like thick concrete walls, though the blast would potentially flatten those).
UV radiation is probably also effective, but I don't know anything about short wavelength EM emitted by a nuclear fireball, so I won't consider that here. You might want to look it up, though.
In any case, thermal, UV or direct exposure to nuclear radiation requires line of sight to the blast. Sheltered nanothingies will be largely safe. If they're engulfed in fire that will probably sort them out though, but you need to be a lot closer to ground zero to have everything catch fire (more like 1.2km) as a lot more energy is required (more like 147J/cm2). In the absense of combustible materials (eg, a very concretey modern city or dry desert) a fire will likely not start and again, sheltered nanomechanisms will likely survive. A strike with multiple warheads with overlapping areas of destruction is probably the best way to ensure that the number of survivors is minimised.
Burying the little things in debris is probably highly effective. They can't hold much power, so they'll become inert before they can escape. On the other hand, those far enough from a nuclear explosion may be distributed more widely by the air blast, making the outbreak harder to deal with.
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EMP will be fairly ineffective, because you need long-ish conductive structures to pick up the electrical fields. Nanomechanisms are so tiny that the voltage difference across them is just too low to do any kind of meaningful damage. Larger devices (microchip sized) can be affected, but generally only because of the metal interconnects they are attached to.
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I would not hold high hopes on nukes being any good or effective about nanoscale machinery, despite Starfish providing good enough answer as general assumptions.
The reason for that is a possible multitude of deployment tactics. Even with your chosen one "swarm of locusts, like a black cloud of death" there is plenty of options.
Best countermeasures are similar machines, and if another side does not have one - they pretty much are toast.
as a model to think about, a modeling example which may have similar properties as named nanomachines and on the topic of the effectiveness of nukes in the case - it possible to take viral infections(which not exactly visible, but still effective enough) or microorganisms which exists in soil, or general dust present in atmosphere.
To get visible effects of the presence - the nanomachines may be indeed like dust particles - dust like a shell for few nanomachines which they are using as a carrier(like those or similar to particles which are suggested to counter global warming in some studies - those flying high for a long time, and with changing properties introduced by nanite structures in them they can fly as they wish). Then the most of the mass of the stuff will be quite robust and inert material - thus it pointless to imagine them being easily vulnerable by UV, EMP, certain levels of radiation, light burns or air pressure.
They can clump in something bigger - like mosquito size and indeed fly as a cloud of insects instead being delivered by missile or airplane or crawl underground or other less detectable ways of deploying them.
But even with mosquito size carriers - which they may collect for the means of keeping communications with base or other necessities - they probably do not have to be a super-dense cloud of the stuff and even if they have for some reason to gather in a visible cloud it not likely to be one super big but many small ones on a distance from each other - so it can be spread of many smaller clouds - which will make certain average density of the machinery in the area which does not have to be high - thus making nukes not so effective as it would be against buildings and humans.
Dust particles of 10um size, in a concentration of around 10mg per cubic meter, are enough to form visibility problems like that [](https://i.stack.imgur.com/nbKRW.jpg)
And if we take 2Mt airburst from nuke map, we can hope for 2.3 km radius cleanup(most likely, but not fully) to 10.3 km radius cleanup(less likely, not fully)
2.3km radius is:
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> 500 rem radiation dose; without medical treatment, there can be
> expected between 50% and 90% mortality from acute effects alone.
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So it is not an immediate hell of fire cleanup, it just some percentage of cells in a big body are destroyed enough to malfunction - but it does not mean all of them are destroyed - soo the same for the nanomachines - it won't be 100% cleanup of a territory.
50m height and that smog density of 10mg/m3, and 2.3 radus (4.6km diameter) of those nanites loss will be about 8 ton of them being destroyed(if we assume 100% destruction at 500 rem level). Considering you have developed a nanotech situation(with those buildings and such) it does not seem like it will be big loss for the stuff.
In general, having a developed nanotech situation, if the other side does not deploy countermeasures of similar nature - it stands no chances. And nuke deployment agony won't help them that much.
Countermeasures of a similar nature do not mean a battle of clouds - it can be up to level individual nanohazard suits - which form some penetration barrier. If those are dummer version nanites - then suitable antibodies or something. Or a shell of nanites of a different kind that consumes attacking dust nanites as fast as they land on the skin/cloth. etc.
**To conclude**
Using nukes as countermeasures won't be effective and more so it will be more self-destructive. And if you have to use nukes - best you can do is to target those who are benefiting and controlling that nanite deployment.
Considering developed nanotech situation you have - building buildings I consider a sign of mature and abundant nanotech which then probably is used everywhere(most likely) replacing at least 90% of our todays doing with that assistance - and then it pretty much all-powerful situation to control any live organisms which do not have proper countermeasures.(maybe soil bacteria may be exempt - but only for reason there are too many of them, too deep and they mine their own business and not worth attention that much. require to spend too much energy for too little gain)
**a tip**
you may reconsider the nature of nanites, instead of imagining them like some nano fog and abstract small things, you may try to model them, imagine them as like 1-2um thick wires(which internally consist of 1000's if smaller wires, that internal structure makes it possible to actuate and do some magic. I call it smart matter, and [there](https://im42group.wordpress.com/tag/smartmatter/) are few articles about it) of 0.1-1-100cm length's(different sizes). wires which can act like worms or snakes of their size, so as fiber like wool, glass fiber etc with capabilities to form ropes, fabric, beams, whatever you may imagine carbon fiber or fiberglass to be used for etc etc.
It may make it easier for you to imagine the properties of objects made of those 2d nanites, and it is a possible direction of nanotech development(lookup for "artificial muscles"), in some sense maybe even more practical, with plenty of utilitarian use. And it can be easier mapped to the objects and stuff we have today, with additional properties which come from the flexibility of arrangement of those microwires.
It may help to imagine more interesting deployment tactics and countermeasures tactics or helplessness in the absence of those countermeasures. There are endless ways to spin stuff in those circumstances - any flying apparatus (airplane, blimp, missile) reaching the area of deployment and then disappearing in dust cloud falling on the area. Small worm-like stuff digging sub mm tunnels network under area 2-3-5km deep underground and bursting out covering everything with them in a matter of minutes when the time comes. Disguise as usual live organisms wandering around and blasting on command in small particles to glue to anything you may target etc etc.
So as it is easy to tune the situation, when both sides have the nanotech, to any outcome as it is typical "shield vs sword" situation
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There are known human survivors that were as near as 100m from ground zero in the world war II nuke attacks. What likely saved them is their thermal mass, and that of the obstacles shading them.
Something very small does not have that luxury - if an environment of (conductive/convective) unbearable heat is created around it, it has no choice but to be very quickly heated up to that level, destroying it to the core.
Radiant heat could be dealt with up to a certain level by being reflective - however, that would put up the complex question whether anything smaller than the wavelength of IR radiation can be made an efficient enough reflector (compare an intact razor edge - it looks dark because it is actually thinner than visible light)...
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**Yes**, if the nanites are solar powered.
You could use nuclear bombs to throw up large dust clouds (or cause a volcanic eruption) which would darken the sky for some time and deprive the nanites of their power source. Volcanic eruptions can also cause global acid rains.
Of course the collateral damage would be significant.
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Following on from Starfish Primes answer, the nano-machines can be blown easily, and as a result can be compressed into a smaller, more compact, cloud. This can then be more easily destroyed with a nuke.
The procedure could be as follows;
1. Large fans are positioned to push the swarm down and inwards, the fanse could possibly be jet engines as they have a very strong backwards flow, and are easily available.
2. Drop a nuke on the cloud.
[](https://i.stack.imgur.com/e0FFm.png)
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I have a human character who had his mind transferred to a computer via a method where his brain was gradually replaced with digital parts to preserve his consciousness. (Depending on your view of the Ship of Theseus thought experiment, he is still his original self.) This happened in the 22nd century.
If he continuously replaces or upgrades the computer he is stored on, will he be able to live indefinitely, or at least for 17 million years to be able to take place in my story?
Things to consider:
* The computer does not need to be fully powered off to replace parts
* He keeps his brain in a place safe from theft, EMPs, etc.
* He can still run a business through an Android body, so he can afford the repairs/upgrades
Edit: I am looking for if his mind can last that long psychologically. Will his mind degrade over time even if it is no longer biological? Will he still have a will to live after so long?
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If the simulation is faithful, I think that person's experiences will be basically the same as an immortal or very long-lived person living in the real world. So, the question becomes, could a person last that long psychologically, in general?
I think certainly, living for that long is not for the faint of heart! There are many people who won't be able to live that long without tiring of life. But humans are a diverse lot, so certainly, **I do think there are some people** who would have no problems living that long. I can't speak for real life, since as of now, no one's ever been able to live that long, but there are plenty of examples of characters in fiction who I think have the right mental mindset to live for that long without suffering depression and other adverse side effects. See this TV Tropes page for some examples of such characters: <https://tvtropes.org/pmwiki/pmwiki.php/Main/LivingForeverIsAwesome>
I personally know of several characters in fiction who have lived much longer then 17 million years, and still seem fairly stable, mental health wise.
One such character is the [Face of Boe](https://tardis.wikia.com/wiki/Face_of_Boe), from Doctor Who. He is thought to be billions of years old.
Another character is [Ashildr](https://tardis.wikia.com/wiki/Ashildr), also from Doctor Who. It should be noted that she was initially a normal human Viking girl from the 9th century, and only became immortal because of the Doctor's intervention. She continues living until the end of the end of time, and becomes the last living being in the universe. It should also be noted that like any us with our **fallible memories**, her memories of older experiences faded with time. She in fact at one point forgot her own name.
I suspect that **memory loss plays a vital role** in maintaining one's sanity as a long-lived being. If you only mostly remember the last several hundred years or so, that I think is much more manageable than having to deal with memories of billions and trillions of years of experiences.
Another set of characters I would like to mention are [Kaguya](https://en.touhouwiki.net/wiki/Kaguya_Houraisan), [Eirin](https://en.touhouwiki.net/wiki/Eirin_Yagokoro), and [Mokou](https://en.touhouwiki.net/wiki/Fujiwara_no_Mokou) of Touhou Project, all of whom have drunk the Hourai Elixir, and are all completely immortal. Although Mokou was formerly a normal human Japanese girl from around the 8th century, and as of current canon is only around 1300 years old, Kaguya and Eirin are Lunarians, and are commonly thought to be millions of years old. There's an amazing Touhou fanwork called "[The Immortal Who Saw the Death of the Universe](https://dynasty-scans.com/chapters/the_immortal_who_saw_the_death_of_the_universe_first_part)" by Alison Airlines that's set in the far future which I feel explores the mental states of these immortals in a particularly insightful way. At the end of the first chapter, this fanwork includes a headcanon that explains why *Houraijin* (ones who have taken the Hourai Elixir) don't get depressed:
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> *Akyuu*: "Houraijin's mood may temporarily swing, but they never get chronically depressed. Which is natural, as illness is foreign to them."
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> *Byakuren*: "Brain waves of a Houraijin are very calm, as if the subject had a Zen monk's mind. Perhaps this is why they lead such a quiet life in the Bamboo Forest."
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Some food for thought.
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After the first 120 years, there are likely to be no biological parts left. Our cells can only divide so many times before they stop and die. Depression is largely a biological function, so I would not expect suicide to be an issue after the first 120 years.
Much of what makes us individuals is tied to our biological systems. If, for example, the section of my brain that is scarred from an injury were to be repaired with a perfect electronic replacement, the immediate change would be reinstatement of the ability to experience emotions normally, with the known side effects of improved social ability, better ability to prioritize and focus, and improved memory function. As long as I can get replacement part, I would expect no degradation of this facility over time.
Electronics are not affected by chemicals, so my replacement part would not be subject to fatigue, drugs, hormones, hypoxia, or any number of "environmental" issues that affect biological systems.
As the biological portions of the brain die and are replaced with electronic alternatives, things would change. Emotions are in large part governed hormonally. In my case, having just restored my ability to experience emotions through replacing a nerve connection with electronics, would I lose the ability to have emotions at all as the ability to create and metabolize hormones was lost with the biological systems?
Without an electronic analog to the endorphine system, the person would cease to have emotions. With the absence of emotions, they lose the ability to recognize or respond to normal social stimuli, have reduced ability to prioritize, focus, and remember information.
Human memory is incredibly compressed. We don't remember entire events, only the novel aspects of the events. We fill in the gaps between he "bookends" with reasonable speculation. After 17M years, unless their memory model is changed with a hardware upgrade, they will probably remember their first time at summer camp, but have compressed all other wilderness experiences into a single homogeneous blur. Now, with that said, once they have a certain amoung of electronic modification, it is possible that their memory model could be altered to incorporate mechanical augmentation such as capturing and restreaming experiences.
A number of people (@L. Dutch) have commented on the emotional toll of isolation as it applies to neurotypical humans. However, this person will no longer be neurotypical after a certain point - their neurons will all be replaced with electronics, and the endocrine system gone or replaced with electronic analogues. As one who does not experience normal emotions, I do not experience the effects of isolation in the same way as neurotypical people. I am more than satisfied in that regard by visiting a fast food drive through window once a day. I would expect the character would end up with a similar lack of interest in social interaction.
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You have plenty of writers who have used in their stories computers lasting for million of years.
From this point of view, I see no big issues.
On the other hand, a human consciousness lasting 17 million years would have to face some problems. The first that comes to mind is the company of others.
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> Good friends we had, good friends we've lost along the way. In this bright future you can't forget your past, so dry your tears, I say. [credits](https://www.azlyrics.com/lyrics/bobmarley/nowomannocry.html)
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We humans are gregarious creatures, and tend to develop affection and bonding with some other humans. Going through the process of losing some of this bond is painful. I can barely imagine what it means to live a century and keep counting all the people you cared of and who are now gone. Doing this for 17 million years is going to be excruciating.
Moreover, in a time span of 17 million years is long that it is arguable that your character would have human company at all. I mean, around [17 million years ago](https://www.timelines.ws/00070_1MIL.HTML) the hominids just started diverging from the orangutan. Though from a scientific perspective it would be interesting to follow live the evolution of species, one has a lot of spare time to fill with likely no company.
Prolonged isolation is really tough on humans, and I am afraid your character would end up with at least some psychological issues if he is to be alone. But since you mention he has a business, I imagine you imply that there are others of his kind, so maybe he can mitigate the loneliness and find a decent way of passing time.
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# I've got this terrible pain in all the diodes down my left hand side
It would certainly not be the first character to have lived that long, nor the first with severe mental health problems. Though not as a result of having lived that long in Marvin's case, but he ended up 37 times as old as the universe and still with that pain in all those diodes.
Genuine people personalities are not going to help here, but then again, most emotions are a result of hormones and once you've replaced everything with electronics that's no longer a problem. The real problem is that the desire to continue to exist is also emotional, and once everything has been replaced with a computer, what's actually keeping your character going?
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There are other minor issues like the keeping a single civilisation going that long to maintain a line in compatible technology. Maintaining an economic system that can be used in a suitable manner to provide parts.
Ignoring all the random events, assuming redundant backups and all the usual hardening of systems. The level of economic control required to maintain the necessary infrastructure may require your character to become the controlling entity of a civilisation, which in turn risks overthrow and deliberate destruction, is that the story you want to tell?
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Seventeen million years is a very long time. Long enough for (say) the miniscule probability of being hit by lightning in any given year to become significant. The odds are approximately 700,000 : 1. On average, over 17 million years, this should happen over 20 times.
In other words, this individual is likely to die from some kind of freak accident. 17 million years is geologically significant, after all. The odds that any particular spot on the Earth's surface will be stable for that length of time are very very small. If an earthquake, or nuclear war, or the city being flooded don't do them in, odds are a fire, a power failure, or the futuristic equivalent to a hard disk head crash will.
To be resilient against this, this person(?) would essentially need to turn into the Ghost in the Machine. Surviving that long means being transferred to a computer *network*, and living in the internet, with the program that is their mind being split into running across a redundant network so it never falls offline. The problem there is that now they depend on the network to live, and if it falls apart, they die.
Similar problems arise if you want to have him sit dormant somewhere for most of that time, and then be re-activated. Unless someone is actively copying and maintaining the data in an archive somewhere, after millions of years, the data will almost certainly have degraded. Any given material undergoes chemical reactions that slowly degrade, corrode, or otherwise increase their entropy. These reactions generally progress at a rate so slow as to be negligible most of the time. But over millions of years these reactions would likely efface the delicate structures storing the information.
This is one of the reasons why Jurassic Park won't work; DNA spontaneously degrades over time. Long chunks break apart into smaller ones; the time difference between the age of the dinosaurs and us is so much the DNA in the amber will have completely degraded to uselessness.
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It's quite possible that your human will suicide.
If he doesn't start forgetting things he will progressively increase its memories during his lifespan.
After living 17 million years, don't you think your mind will be some different? What is your reason to live so much? Luxury, comfort, enjoyment and money? After that age, everything will be secondary. I'm quite sure a person who lives so much time will be very bored, a maybe he will suicide.
For example, I love to play video games, but after play some time a game I start getting bored of it and I change to other game. Even more, I get exhausted of first shooter games and I play almost nothing of them.
If your character also loves video games, what he will do in 17 million years? He will have played all the games made and for making, he will have experience all the game genres and he will note that all of them are the same thing but just with a different name. He will not hold more games.
The same could happen with life. He may not want to live anymore.
So he must be able to forget, otherwise, everything would be old and boring. And even more, we don't know of his mind could handle that amount of knowledge and memories, maybe he will get crazy or its mind could start to fail.
But that is also a problem, after some time he will forget his reason to live. Why is he living for?
I strongly recommend adding some "updates" or "fixes" to its brain's software in order to not lose its wills nor affect it phycology.
I hope this will be useful as an answer, if not, I'll try to edit it or ultimately delete it.
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I don't know why the other answers lean on the character going suicidal. There is no data to support that, mostly because no one has lived that much. Anyway getting older can make people more accepting of death, but it doesn't make them more suicidal.
Now that we are past that, what I see here is a post-singularity version of a thought experiment called [the ship of Theseus](https://en.m.wikipedia.org/wiki/Ship_of_Theseus). Food for thought. Whether the character stays the same is up to individual interpretation.
As for integrity: if his mind is digital, it may be resistant to time. He is all 0's and 1's, and as long as storage and memory parts get proper maintenance, he won't degrade from a hardware point of view. As for software, yeah he may end up corrupting his digital self if he is not careful. But with 22nd century tech, he'll most likely have backups. Even more interestingly, he may spawn copies of himself that evolve differently, each instance going in a different way. More food for thought.
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That's impossible to say.
Today's neuroscience doesn't have any data about humans who are older than a bit over 100 years. Dementia is a problem for people of that age, but there are biological reasons for it. Having an electronic brain instead of a biological one generates another unknown variable. There is no way to tell how an electronic brain would be affected by dementia. So you can do whatever works best for your story.
Whether he would *want* to live that long: The statistics are against him.
In the United States alone, there are [2.7 million deaths each year](https://www.cdc.gov/nchs/fastats/deaths.htm) and [45,000 deaths by suicide](https://afsp.org/about-suicide/suicide-statistics/). So the risk of getting depressed and killing oneself over the course of one human life is 1.66%. A person living 170000 consecutive human lives would thus have a death by suicide risk of 1 - 0.9833 ^ 170000. This number is so close to 100% that the Windows desktop calculator can't display it.
But maybe some people simply lack any suicidal tendencies at all, so they won't kill themselves even in millions of years? Who knows? We don't have any data in that regard.
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If the consciousness of the main character is converted in a digital form raises a number of concerns:
**The hardware the consciousness runs on** is vulnerable to corruptions. Computers use crude electric methods to read bits, but there may be permutations sometimes. Meaning a 1 can erroneously become a 0. There are algorithms to mitigate this risk, but given enough time errors can still pass through. Another way to mitigate the risk is to run multiple simulations of his\* consciousness at once and choose the new state by looking which one occurred the most. But given enough time even this can give errors. The result can be that his personality changes during the journey through hardware corruptions. These errors will also apply on quantum hardware or any other engineered hardware subjected to physics.
**The main character becomes disconnected from his original body** and therefore there are concerns with identity and gender. Given enough time, wouldn't you want to try something differently? It is plausible given this time that the main character changes.
**It depends on the environment of the ship**. If the main character has to survive 17 million years in solitude then I don't think he will make it. He will try furiously to end his life because it is the only thing left to do. The way I see the main character surviving is by giving him the sensation that there are still many things left to experience. Either by wiping his memory once in a while and have him repeating things. Or by having the environment be a vast complex place like paradise or a magical kingdom where he feels he has importance and fulfillment. He might need to live in a simulation for that.
I think regardless, the character will be a very different person after the 17 million years but I think it is possible he keeps the same *soul*.
* *The him can also be her, I used him throughout the discussion*
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While it *is* possible to live that long, however likely the chance they would kill themselves long before them. It mainly depends on if they are active for the **full** 17 million years.
If they were to be in a hibernation mode, rarely (Perhaps every million years or so?) waking up and looking at the outside world to note any major occurances, then yes it may be very possible for them to stay completely intact mentally.
Remaining away for even a rough 10% of that time would likely change, or even break them mentally. Pushing them closer towards a self-destruction. However we dont know *what* the effects of incredible age and experience are, and likely also depends on how strong the person is mentally.
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Even for just 500 years, I doubt there will be any biological body remains, and after that I can't say that he is can be categorized as human anymore. This means he will likely adapt to new psychological state that surpass mortal human as a cybernetic hybrid. So he can safely programmed his own brain to not doing suicide and try his best to prolonged and update his existence (therefore also avoid boredom). And we can assume from there it would be a walk in the park for him to become godlike entity in a first million of years.
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# The Curious Case of Bowerick Wowbagger the Infinitely Prolonged
A recurring character in the Hitchiker's Guide to the Galaxy franchise, Bowerick is an alien who became immortal after "an unfortunate incident with an irrational particle accelerator, a liquid lunch and a pair of rubber bands." Nobody ever was able to repeat this; anyone who tries ends up "looking very silly, or dead, or both."
He initially great time, laughing at other peoples' funerals, making a mint from life insurance and long-term investment, and "generally outliving the hell out of everybody." After a few centuries he is one of the richest and most powerful beings extant.
In the end, it was the Sunday Afternoons that got to him. You know what I'm talking about, that horribly boring time of day when there's nothing to do, nothing to see, and everything's just generally blah. **Over time more and more of his life grew to be like this, and it began to pall for him. The end result was that "he began to despise the Universe in general, and everybody in it in particular."**
In order to alleviate the boredom, he decides to insult the Universe, by insulting everybody in it. Individually, personally, *and in alphabetical order.* That's how cracked he'd become. He spent his fortune acquiring the best ship he could, the best computer, and the best entertainment system, and then started out. When he finally gets to "Z" he is killed by the Great Prophet Zarquon, who was particularly irked by Wowbagger's insult, thus ending Wowbagger's eternal suffering.
**It is worth mentioning that creatures that are *born* immortal are capable of handling immortality (usually by ceasing to care about it); those who are born mortal are unable to stop caring.**
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### Making the first money
Data integrity over time will be a problem. The bio data storage needs to be copied, functions need to be emulated. Once that is done, your personality will want to expand processing and memory capacity in order to secure it's own integrity and superiority when competing with other humans on Amazon Turk.
### Securing existence
Next thing it wants to do is setting up automatic back ups on several continents with their own independent power source. He wants to extend his moneymaking to pay for a trip to space next. Being away from those pesky humans further secures his longevity. He might then beam his mind state into orbit or back down continuously so that he always has an up to date security copy.
### Longevity Memory
Once he got sufficiently complex and able to code, he probably wants to rewrite his personal operating system to make it incompatible with existing or new comuterviruses. The danger is of course, that one or all of the steps change his personality beyond recognition. He might want to store a security copy of himself on a durable memory medium, for example in holographic glass.
<https://www.allaboutcircuits.com/news/5d-data-storage-how-does-it-work-and-when-can-we-use-it/>
### Useless Copy
Of course he doesn't need those copies anymore as soon as he did his update. Worse, the update could change his personality, which was the entire reason for making a copy in the first place. But does Update want to change back and become Copy? Probably not.
### Stolen Memories
One or several of the security copies may be retrieved by someone and brought to life. Shocked by what he became, Copy may become the worst enemy of Update. Both with comparable abilities physically and talent-wise, both know which passwords the other might probably use, they might be formidable enemies for each other. Also philosophically, they might never find out who of them is the real man. Update has a continued stream of memories, but Copy is closer to the original without changed personality.
### Work slaves
No matter who wins, Survivor might want to ensure that never again, a security storage gets away. And that might be too late: some human might have found a way to edit the memories and make fine little work slaves from them. The ensuing battle between Survivor and humanity may leave both in a desperate state.
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Let me preface this by saying I've already finished the piece this question is about *but* I'm wondering if I missed something in my logic so I want to see if there's something you see that I didn't. The basic question is for what tangible, material reason or reasons (so not matters of philosophy or just "how evil can we be today?"), would a star system, that isn't doing badly and isn't overcrowded, invade another star system that is no better than their own? The system they attack has the same number of habitable worlds, same survey numbers on quality, and quantity of raw materials, same standing population. Especially is there a reason to attack a system that isn't better than yours in such a way as to risk the habitability of it's only terrestrial world?
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> The basic question is for what tangible, material reason or reasons (so not matters of philosophy or just "how evil can we be today?"), would a star system, that isn't doing badly and isn't overcrowded, invade another star system that is no better than their own ?
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Greed is about the only reason that makes sense. Maybe ego.
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The reason one group attacks another come down to six things :
* **Desperation** - They have something you need (or will need "soon").
* **Greed** - They have something you want (but don't really need).
* **Ego** - Someone in charge can insist this happens and their ego is linked to how much they have control over. The words emperor and monarch comes to mind.
* **Cultural Xenophobia** - They are "they". You just hate everyone else.
* **Fear** - For whatever reason your culture fears the other one. This could be legitimate fear or fear based on incomplete or poorly interpreted knowledge or a cultural victim complex due to historic events.
* **Revenge** - Payback time ! :-)
And typically it will be a bit of all of them.
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> Especially is there a reason to attack a system that isn't better than yours in such a way as to risk the habitability of it's only terrestrial world?
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This depends on the motivation for the attack. An ego trip or cultural xenophobia would be at best ambivalent about destruction, and at worst keen to make it happen.
A fear based attack could be carried out ruthlessly simply on the standard military logic that once you start a war, don't think you can limit it, because you usually can't.
If you're desperate or in need of something they have then this may limit how much destruction you're OK with.
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Assuming your civilization has advanced to the point where interstellar travel is difficult, but possible, I would consider some of the reasons behind European conquest of the Americas and West Indies:
# Space
Not as in *outer* space, I mean room for habitation, agriculture, industry, etc. Europe consists of a finite amount of land [citation needed]. If the available cropland is already in use, but we know of more land across the ocean where establishing sugar plantations will be profitable, why not take that additional land for such purposes? The available land in your solar system will eventually be used up, so risking a land war could happen if there is enough economic drive or your society believes it is at risk of exceeding the system's carrying capacity.
# Nonrenewable resources
Typically this would be mineral resources. Historically, Spain et al. discovered gold, corundum, etc. was abundant in the New World (but probably not enough to constitute [an entire city](https://en.wikipedia.org/wiki/El_Dorado)). It would be profitable to take control of any neighboring resources, especially if these resources were nearing depletion in your solar system. You say they have the same quantity of raw materials, but there's always stealing claiming the resources the others have already exploited.
# Imperialism
Going hand-in-hand with the last reasons, not only is it profitable to conquer, but it is also a show of wealth, power, and probably pride as well. If you successfully conquer the other solar system, some hypothetical third civilization is not likely to threaten you if you control double the resources, manpower, etc. In real life, imperialism occurred over and over throughout history. Assuming your people are human, or very human like in thought and logic, it is not a habit that will die easily.
# Preemptive strike
Who knows, perhaps your neighbors in the next solar system over were going to think of these exact same things. Better if the fighting take place over there, threaten *their* civilians and *their* economy, not yours.
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The reasons for war and (attempted) conquest do not need to be reasonable. Quite often the reasons of war and expansion are purely ideological or structural.
* Example 1:
Was the German Empire just before WW1 overcrowded? Germany had the largest territorial extent ever! Did it lack access to raw materials or to world markets? No, it was one of the largest exporters and had already achieved a position of technological excellence. Was it poorer than its neighbours? No way, it was much richer than Russia (its neighbor to the east, there was no Poland at that time) and about as rich as France. Was it threatened in any way? Nobody could pose a credible threat. And yet they were fixated on the "historic need" to subdue France... They lost.
* Example 2:
The [Ottoman Empire](https://en.wikipedia.org/wiki/Transformation_of_the_Ottoman_Empire) in the second half of the 17th century was one of the world superpowers, it controlled the Black Sea and the eastern and southern Mediterranean, it had vast amounts of fertile land in the Hungarian Plain. It *did* have an overpopulation problem in Anatolia, but that was only one province, and "overpopulation" in Anatolia did not translate to unmanageable numbers. Nobody could pose a significant threat, and all it had to do was to apply mild economic and judicial reforms and encourage internal trade and migration. And what *did* they do? They went and besieged Vienna, lost the war, and began the long journey to oblivion.
* Example 3:
Towards the end of the 19th century several Western European powers, mostly the United Kingdom, France and Germany, but also Portugal and mighty Belgium, started a frenzied effort to gain control over African terriories; this was the [scramble for Africa](https://en.wikipedia.org/wiki/Scramble_for_Africa) that created those magnificent borders with no relationship whatsoever with linguistic or geographic boundaries. There was no reasonable reason for this ill-fated effort; the "new" African colonies were never profitable (as opposed to the "old" colonies established for reasonable reasons), nobody ever even tried to make a case that they would be profitable, and the scramble did bring various European powers into conflict. Less than a century later the European powers abandoned all their African territories...
* Example 4:
The best example of the power of ideology to launch unreasonable wars of conquest is the [First Crusade](https://en.wikipedia.org/wiki/First_Crusade). English, French and German kings and lords started a war of conquest in Palestine, at the very limit of their logistic capacity to project force, wasting vast amounts of treasure and blood in order to conquer some dirt poor but ideologically important towns and useless patches of desert. Had they just wanted to make war on Muslims they did not have to go to Palestine, since Spain was much closer; and, unlike Palestine, Spain would have had many advantages: it was at the logistic limit of the *Arabs* to defend, it is much richer and *not a desert*. But no, they had to go to fight and die in a place far away. The Kingdom of Jerusalem lasted for less than two centuries...
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I can't believe resources would be a sensible reason unless it was a technology-critical resource so honking rare that you'd need to expend the cost of invading systems across interstellar distances to get it. ([Unobtainium](https://en.wikipedia.org/wiki/Unobtainium), anyone?) Honestly, I find that to be remarkably unbelievable. Some ultra-wealthy magnate may send in a mercenary team to steal some... but outright interstellar war? What could possibly be worth that expense?
I'm not even happy with the need to expand. I'm a fan of a phrase I coined, "technology dichotomy." As a micro-publisher, we were plagued with books about time machines that could be activated by bumping a button with your hip... or stories about babbage machines in a civilization that hadn't invented the wheel. The idea that you can be large enough to seriously fight an interstellar war but can't terraform a planet seems, to me, dichotomous. Once you can terraform planets, it's an issue of time + cost to terraform vs cost + loss to conquer. I'm no expert, but I suspect it would be cheaper to terraform every time.
Further, space would seem the very epitome of the easy way toward population control. After all, "[space is disease and death wrapped in darkness and silence.](https://www.youtube.com/watch?v=RlphfLO3MYA)" I suppose it's possible to have bloated planetary populations that can't be spread out through terraforming... but...
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> It's probably much cheaper and far more lucrative for the arms dealers if we fight amongst ourselves.
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That really only leaves two reasons.
**I'm Offended!**
Your official "I'm just out studying the pulsar" crew comes across an alien species and in a classic, "[What? Open gun ports are a sign of PEACE?](https://en.wikipedia.org/wiki/Earth%E2%80%93Minbari_War)" moment blew away the theoretically hostile aliens, thereby starting an interstellar war. You'd think diplomats could work this out with an appropriate sacrifice of human virgins, but in the world of Sci-Fi, war is almost always the result.
**Hate You Chaka!**
My moving tribute to *Deathworld II* by Harry Harrison reflects one of the most primal urges of all (obviously) intelligent species... the desire to not like your neighbor. We hate the Klingons, the Klingons hate us, punt the diplomats, this is war, baby!
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I can see one more reason: a **distraction**. Suppose a civilization is doing fine industrially and scientifically. There is no real shortage of resources, enough to provide for everyone to live a happy life in theory. In practice, however, this doesn't happen. Government is highly authoritarian, and economical and social inequality is increasing over the last *(fitting period of time)* to the point where a few rich folk live in palaces while many starve to death. Of course, people in power are not motivated to solve these problems.
Discontent within the population rises, and traditional measures to silence it with police batons fail. Every month more and more formerly loyal citizens are joining the opposition. Seeing this might result in a rebellion, government might decide that an *external* enemy is better than an internal one, and uses it's mass media to breed hate towards some other civilization that it expects to be reasonably easy to wage war with. Maybe even a diplomatic incident or two is arranged (or faked) to make it look like "they started it first".
This does not bring the population any prosperity whatsoever: if anything, their conditions get worse, and many go to war, never to return home. War drags on for a very long time, and the two civilizations, maybe once former friends, now seem to be bitter enemies forever. On the "bright" side, though, people who formerly were thinking about taking arms against the government, now see a new enemy, and find solace in unity. And the elites stay elites for a while longer, just as they wished.
Reminds me of something...
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The causes of war and, therefore, of conquest can be summarized as power, resources and ideology.
**Power**
If their power potentially threatens your power or sphere of influence. Perhaps not now, but why wait for the inevitable?
**Resources**
Their system has system your civilization needs, will need or just plain wants. Also, related to power especially their access to resources will place their system in galactic geopolitical ascendancy over your system. Resources can include living space. For example: We both need earthlike planets for habitats, theirs is the closest and easiest to reach and conquer.
**Ideology**
"We hold these truths to be sacred, self-evident and the best thing since sliced bread." Our heinous, slime-covered neighbours don't. They're evil. We must crush their horrible system. And, of course, vice versa. We are horrible in their three pairs of eyes.
Ideology is the most complicated factor. It can be any cultural, political, economic or religious institution or factor. Usually, tied up with power and resources either directly or indirectly. It both amplifies and reinforces any decision to wage war.
These three concepts have general application. They are the underlying causes. The putative reasons for going to war may include something like a Zimmerman telegram or the invasion of Poland or crossing the Rubicon, however, the terrible triad is usually lurking there in the background.
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## People want more space and resources
Although the star-system you speak of is not overcrowded people always want more space, more room to grow. Also this civilisation has not got a matter generator so eventually that solar system would run out of vital resources like metal and silicon. So the civilisation will need more resources as it's population expands.
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**Lack of Empathy**
Could be that the Alien race don't acknwoledge us more than local fauna in their plans for the colonization of the sector.
Like the situation when you are building your home in a little terrain and you dont give a second thought at the ant colony that is going to be removed.
**Diplomacy**
Mayor powers could incite aggression to destabilize a sector under the influence of another empire to gain leverage or start a bigger hegemony.
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Interstellar conquest will be far different from anything else that we have seen or done in history, so it really needs to be in another category. The energy, time, and resources needed to carry out an interstellar war will be so great that normal justifications we accept on Earth simply won't do.
Resources? Any [solar system](http://www.philipmetzger.com/blog/the-pattern-of-resources-in-space/) is overflowing with energy and material resources. The single moon Europa is estimated to have 3 times as much liquid water as the entire planet Earth, and that is one moon out of the 67 orbiting Jupiter, and not counting the other known moons, tens of thousands of asteroids or millions of comets (not to mention all the bodies in the Kruiper belt and cometary halo).
Energy? The sun expends more [energy](http://www.projectrho.com/public_html/rocket/usefultables.php) in a single second than the entire Earth uses in a year (much more actually). A Dyson swarm around the sun is considered the end port of a technological civilizations, and a Level 2 Kardashev civilization in a cosmic scale. (see the Atomic Rockets Boom Table in the link)
Living room? It is estimated there could be up to [60 *billion* planets](http://www.dailygalaxy.com/my_weblog/2013/07/60-billion-planets-of-milky-ways-red-dwarf-stars-could-sustain-water-and-life.html) in the habitable zones around Red Dwarf stars in our galaxy alone. That is like 10 planets for every person alive on Earth today, if we can only get there.
So what could inspire the need or desire for interstellar conquest?
Firstly, there could be some sort of existential threat. IF an alien race has the ability to create a [Nicoll-Dyson beam](https://www.youtube.com/watch?v=RjtFnWh53z0) or fire [Relativistic Kinetic Kill Vehicles](https://infogalactic.com/info/Relativistic_kill_vehicle) (RKKV's). It is obviously desirable to ensure that your civilization isn't suddenly struck by a literally world killing event, so *some* civilizations might be inclined to preemptively eliminate the threat.
The second reason might have to do with how the aliens think. Their motives are alien by definition, so there could be some reason or idea that makes perfect sense to them, but is totally baffling or undecipherable to us. This is sometimes called "[Blue and Orange](http://tvtropes.org/pmwiki/pmwiki.php/Main/BlueAndOrangeMorality)" morality. If this is the case, there are hardly any channels to appeal the decision.
So interstellar war is out unless there is an existential threat to the civilization.
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Why do you assume all those premises? There could always be a reason but it might end up being very contrived with all those limitations. Generally wars are fought for resources and if they both have no material reason to fight then war doesn't usually happen.
But, reasons for things do not have to be logical. A religious reason can very much develop. The Convenent in [Halo](https://en.wikipedia.org/wiki/Halo_(series)) started their war with humans simply because the existence of humans can not fit with their religion. Of course, they also had material motivation because humans controlled planets with Forerunner artifacts.
Another reason might be that one of the 2 species just loves war. Bloodlust driven by a convenient plot point can be used to explain the war starting such as in [Warcraft](https://en.wikipedia.org/wiki/Warcraft). Where the Orcs were basically brainwashed into attacking everything and did so without any logical reason to.
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[Question]
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This is an Ancient Chinese repeating crossbow [](https://i.stack.imgur.com/wo3gl.jpg)
It is fast, light and easy to use, but really weak.
One bolt alone could hurt someone but not kill, 3-4 bolts could actually be deadly but it's a waste of arrows if you plan to arm an army with it.
This one is an Arbalest, slower but stronger, one bolt could easily kill people and even horses or other large animals, and sometimes it could even
partially perforate helmets or plate armors with a bit of luck, but when it didn't perforate armor the impact alone was enough to stagger the enemy.
[](https://i.stack.imgur.com/fn5pe.jpg)
Is there a way to combine the speed of the repeating crossbow with the strength of the Arbalest without the use of gunpowder or other explosion based technology to create a more devastating medieval weapon?
The materials can be anything you can find in nature and process in a smith or a laboratory with some time and effort, it doesn't need to be necessarily easy to craft.
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Yes, depending on what you classify medieval weapon. Now your easiest option is to just scale it up. This was actually done with the above Chinese design. Making it larger increased its power. It also becomes to heavy to carry but you didn't specifically list that as a requirement.
[](https://i.stack.imgur.com/u2zQx.jpg)
The Greeks had a similar siege crossbow, the [polybolos](https://en.wikipedia.org/wiki/Polybolos). Both could be made much stronger when made out of metal. This would mean they need to be operated by more then one person. But a large crank operated by two or three guys would get you far. But these aren't mobile, at least by a single person.
If you want the mobility of a regular crossbow something gotta give. You either get reduced but respectable power or move further and further from non-explosive but also non-medieval technology. The limitation with handheld systems is that the draw weight needs to be low enough to be done quickly for the next shot, that's in opposition with the strong draw of an arbalest.
Easiest way around this? Cheat. By using motors and electricity. This would give you the power you need to draw a heavier bow while keeping it small enough to be carried by one man. But I doubt this is what you want.
Now you could compromise and go for something like a stirrup and belt hook. The system used the muscles of standing up to load the crossbow. The string was hooked to the belt and a foot in a stirrup kept the bow down. Simply standing up armed it. This system is much stronger then a repeating crossbow as it's not the hand but the entire back and legs pulling the string.
[](https://i.stack.imgur.com/eTseo.jpg)
But this will be nowhere near a true arbalest. However if you create a system that allowed standing up to load but is magazine fed you get a decent compromise I think. It can fire as fast as you can squat, which is a pretty decent rate of fire. Compound crossbows also severely lower the required draw weight and combined with some modern materials could give you an improvement.
Now if that's not good enough I really do think you need to power it with something that's not muscle.
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I like the crank system on that big crossbow. It allows incremental delivery of power which is then stored in the main limb then delivered all at once when the bolt is fired. I could imagine that a crank system like this could have gears allowing one to pull back a really big piece of metal. This could store enough energy for multiple really strong shots.
If you store more energy, you can use it incrementally for successive shots. For example, imagine the heavy crossbow but with an even larger backwards facing limb. That is cranked back. Instead of propelling a quarrel, the big limb is released incrementally, each release pulling back the small limb. You could store enough energy in the big limb for several shots of the small limb.
You could also store energy in a spring or coil, either by pulling it back or compressing it, and again incrementally releasing the big storage spring to draw back the string and fire the crossbow.
The more energy you store in a mechanical device the greater the risk of catastrophic failure.
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In short no, not if you want it to be a medieval weapon.
What a crossbow is a spring that stores kinetic energy so that it can be slowly added to and then released suddenly. Essentially spreading out the energy input over a large time. If you want to speed this up then you need something that can deliver the energy quickly and for that we've got:
* chemicals i.e. gunpowder (which you've ruled out)
* electronics in the form of motors or linear solenoids (which is definitely not medieval)
* or hydropneumatics in the form of fast acting cylinders (which is, again, definitely not medieval and requires you to haul a compression system around with you.)
Another problem is that in order to prevent jamming the bolts of repeating crossbows are unflighted (no guide feathers). This limits their range and accuracy, it may also impact on their ability to pierce armour. But it also makes them incredibly cheap to make.
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One of my friends had this crazy idea for a D&D game that I rather liked, but couldn't quite figure out the mechanics of it. Basically you build a "gattling crossbow."
You get a series of bows like your arbalest, and rig them into a machine. This machine rotates them around a central axis, and as they rotate, a gear engages to draw back the string. Then the bow reaches the 1'o'clock position (assuming it is rotating counter-clockwise) an arrow is dropped onto it (one of the issues here is making sure it lands properly for firing), and then when it reaches 12'o'clock the string is loosed.
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# Tech history review
If you look at automatic guns, the energy for the shot comes from the gunpowder, the energy for reload in most cases comes from shot recoil. (There are some large gatlings that are spun-up with an electric motor.) But even moving the bolt manually is fine as long as the bullet for the next shot is loaded automatically (like more or less all infantry riffles in the 20th century do).
The problem with crossbow and similar devices: The energy for the shot comes from the deformation of the bow. So, putting an arrow onto the crossbow is the lesser evil, one still needs to crank the bow into the firing position.
And yes, proper springs are hard. Basically, a mass-produced durable metal spring is a 20th century endeavour. Just look how the suspension of cars used to look like in 40s-60s!
# Options for storing energy
So, we need some way to store and energy for multiple shots of the crossbow. The first option is gunpowder, duh, but let's rule it out. What else do we have?
* Gunpowder – obviously. But wait. Gunpowder is known in somewhat advanced medieval setting, just not that extensively used, because guns are hard.
One could use a piston with gunpowder, a "mini-gun" to crank the bow. The upside: it would be reasonably fast, even with all the preparation and measuring and pouring and igniting the gunpowder. The downside: why would you use the gunpowder to crank the bow if you could use it (with less transmission losses) to hurl the projective towards the enemy? It might be that arming and firing a piston (while having cover) is easier that trying to fire it in combat. But on the flip side, the bow cannot stay cranked for long, so much for the preparation in advance.
* Bending energy (springs) – springs are hard. We are already at the limit of what was technologically possible in medieval setting. If they could do better springs, they'd do a stringer crossbow / arbalest / whatever, not a weaker repeating one.
* Kinetic energy – slowly putting up a large weight or pumping water upwards. It's doable, but immediately confines the arbalest to a stationery position. Even rotation and tilting for aiming might be hard.
* Electric motors, combustion motors – just no.
* Steam – while steam-powered guns and reloading arbalests from a central steam-powered shaft sound very cool, that's steampunk, not medieval setting. Wrong era, sorry!
* Stronger muscles. This goes in the direction of a leg-sprung crossbow. Use two people to crank the bow? Use a horse or some other animal? Go biopunk and *craft* an animal / an out-of-body muscle to crank the bow?
* [Bimetalic strips](https://en.wikipedia.org/wiki/Bimetallic_strip). The are some known (to us) combinations of metals that loose and regain their shape basing on temperature. Adjust that to the bow, heat it when need to crank up.
This assumes the knowledge of such effect in the setting and availability of the metallurgy to pump up a considerable amount of the metals required. Next, a source of heat (basically, fire) is needed to reload. Or we could use gunpowder for that!
* Compressed air – there *were* some military grade air riffles in the end of 19th century. Airsoft gets not so soft and goes to war! The problem is: you need a source of compressed air (which means: a compressor, an engine to power it, and a storage tank – at least in the castle) and a proper tanks at the riffle / crossbow. With medieval technology all this might pose an unsolvable problem. And again: if you can shoot bullets with this, why bother with bolts?
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With terraforming, how to do it and how long it takes depends largely on the planet in question. Worlds such as Venus may be nigh-impossible to terraform, whereas worlds more similar to prebiotic Earth might be very easy to do so. Ideally a human race that is new to terraforming would start with a planet that is “easy”, so what type of terrestrial planet would be easiest to terraform, and how would we do this?
Some background information: by this point civilisation has developed to a post-scarcity condition, possessing nanofactories and advanced robot drones to perform heavy labour. These terraformers have just arrived on-site in their new solar system and have no contact with earth. They have access to the in-situ resources on this planet and any moons it may have but none other than this.
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/What would the easiest planet to terraform look like?/
**Accidentally terraformed.**
Separated from his mission to the target system, Daron made landfall on this lifeless world suspecting that there might be giant jewels laying on the ground. There actually were, and so he spent a few days collecting them, then got back into his ship and hurried to catch up.
The microbial occupants of his leavings found circumstances in their new world much to their liking, and began to remake the surface according to their abilities and needs. Return visitors decades later found the surface teeming with life. Also pretty smelly. The world is referred to as "Daron's Dump" because of its provenance.
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You've already answered your own question with "prebiotic Earth". Already has a reasonable atmosphere and magnetosphere, mineral rich crust, substantial water inventory.
If you don't have a decent neutral atmosphere already (eg. plenty of nitrogen) importing it from elsewhere will be near-impossible unless you can shift around small moons on a whim, which more or less requires soft scifi super tech. Similarly, if there isn't a decent amount of water or at least ice available, importing an ocean and biosphere's worth will take you forever.
You don't necessarily need a nice mineral supply, but if you don't have at least some rocky surface it'll be difficult to prevent nutrient and biological matter loss, eg. on a deep ocean world you can seed the surface with plankton friendly nutrients all you like, but once the dead stuff and poop sinks you'll probably never cycle it back to the surface through hundreds of kilometres of water.
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A planet that is slightly too cold for liquid water, but has water in the form of ice, a nitrogen-oxygen atmosphere like Earth and possesses large deposits of fossil fuels or other flammable carbon compounds. Fossil fuels imply that the planet once had an ecosystem, but for some reason the planet got a lot colder and the ecosystem collapsed. A possible explanation could be that its star went into a phase of lower luminosity or that the planets orbit got changed somehow.
Humanity could terraform such a planet just like it is currently in the process of terraforming Earth: By burning those carbon compounds, blowing lots of carbon-dioxide into the atmosphere and thus creating a greenhouse effect that increases the temperature on the planet. The ice on the planet would melt into water, create oceans and a water cycle and thus create the basis for a new ecosystem.
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## A metallic astroid near the systems frost line
Defining "easy" as the shortest time until it is habitable with the smallest resource investment, planets are all together a bad idea. What is a much quicker, safer and more efficient solution are large habitable space stations using the centrifugal force to stimulate gravity.
Using steel or silumin (aluminium-silizium alloy), you get radi of up to 25 km which means you can get livable areas the between the size of the Brunei or Cyprus and up to Panama or Austria. Using carbon based nano materials, radi of roughly 1000km become possible. Those materials get you the land area of India or Australia on the low end and slightly less than the land area of Earth or the surface of Mars on the high end. on the high end. This assumes you go for small radi and 5x the diameter in length on the low end or for the maximum radi and 10x diameter in length on the high end. Of cause, there is no real length limit. You can have a tube of those looping around the local star as many times as you want. This is then called a Topopolis.
Furthermore, those constructs like coming in pairs, as that helps them with gyroscopic stability. Either add a second cylinder inside or connect the second one using an external superstructure. All it has to do us rotate counterclockwise.
## The Advantages
Choice of location those stations can be built wherever you want/need them. As your fust step in settling a solar system should be the establishment of space based industry anyways, those habitats benefit from the low launch cost. Just get an icy, rocky, carboniferous and metallic astroid and equip them with mass drivers, laser launchers or launch tethers. Then, set up solar power satellites in low solar orbits, which beam you the energy via laser and your industry is set.
Build to your preferences. The habitats are vastly more flexible when it comes to the environments you can build in them. This goes for environmental and social systems. Smaller, more independent habitats can allow more flexible designs and reduce interdependence. If groups are discontent with the way a state is run, they can get their own country.
Planetary protection. You don't antagonize conservationist groups doing this. Just leave the natives, be they bacteria or blue skinned native American stand-ins alone.
Safety. Planets are dangerous. Earthquakes, Tsunamis, Volcanos, Hurricanes, Blizzards, ... What sort of space ork would want to live on a thin layer of rock above a hellish magma-pit? And that's not even considering how fast and easy pathogens, nanotechnology weapons or missiles can be sent from one polity to another. And that's not to mention the radiation issue. Radioactive materials are just strewn about in the environment, only a magnetic field protects from particle radiation and the thing gas layer above you is just transparent to some parts of the UV spectrum. Inhabiting planets is sheer madness!
Ressource efficiency. Per square meter of habitat area you need a few tons of material. A planet is using orders of magnitude more mass per livable area. This is just a waste of resources.
Scalability. A full on habitat smarm can use the entire energy of its star. Terraforming is, even one one uses Birch Worlds to terraform gas giants, stars and black holes, a dead end in that regard. If you want a planet, you can just construct it using hydrogen and a shell. That is the only way your resource efficiency could come close.
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I completely agree with @Pelinore, but to be more verbose...
**Assuming Clarkean Magic technology, all planets can be terraformed**
Why can I say this? Because just as we can keep a body alive almost indefinitely using machinery, given the existence of appropriate machinery and the resources to run those machines, a planet can be forcefully terraformed and kept that way.
So, given that any planet can be terraformed, what would be the easiest to terraform?
Well... if you'll excuse me... but, um... *duh,* a planet that already hosts life and only needs the introduction of terrestrial lifeforms to make it perfect for Terrans.
Yeah... that was probably a bit rude, but please think about it. On the one side of the spectrum are:
* planets like barren, rogue planets where a whole sun must be provided or planets so toxic that serious industrial-grade filtration is needed or gas giants where someone would do it only because they're so honking rich they can stroke their ego with it. Planets that would be impossible were it not for the Clarkean Magic technology that permits it,
and the other side of the spectrum, which happens to be...
* Earth.
By definition, whatever planet is closest to Earth is the easiest one to terraform.
*If this doesn't answer your question, then you weren't ready to ask it. May I suggest using the [Question Sandbox](https://worldbuilding.meta.stackexchange.com/q/9981/40609), where you can perfect your question before introducing it to Main?*
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There is actually a quite fitting example in reality. In [JRE #1609](https://soundcloud.com/sevensagesbass/the-joe-rogan-experience-jre-1609-elon-musk) Elon Musk talks about the possibility of terraforming Mars.
**Atmosphere**:
There is a lot of frozen CO2 beyond which could help build an atomsphere on Mars if we somehow managed to release it. So a suitable amount of CO2 residing on a planet without an atmosphere sure helps with terraforming. But NASA claims that even when releasing all CO2 on mars NASA we could only reach 60% of the atmospheric pressure of earth. Although it is impossible to do with current technology (Musk suggests firing atom bombs on mars btw) it may be possible some day.
**Light**:
Lets stick to Mars. [Light is also a deciding factor](http://tomatosphere.letstalkscience.ca/Resources/library/ArticleId/5421/is-there-enough-light-on-mars-to-grow-plants.aspx) when it comes to growing food in order to make a planet habitable.
**Gravity/Size**:
The human body is optimized for earths gravity. [Living in an environment with different gravity has subsequential consequences](https://www.nature.com/scitable/blog/scibytes/cosmic_travels_inc_the_effect/). A planet optimal for terraforming would of course have a similar size to earth. I guess you could reduce gravity by removing a large mass of the planet but this isn't easy to do, eh?
Of course there are a lot of other factors to be considered. I found the [wikipedia page about terraforming mars](https://en.wikipedia.org/wiki/Terraforming_of_Mars#) quite interesting if you want to dive deeper into that topic.
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## A planet that has already had a Great Oxidization Event
You should take a look at the Wikipedia article for Earth's [Great Oxidization Event](https://en.wikipedia.org/wiki/Great_Oxidation_Event). In particular, if you look at the graph at the top of the article you'll see that it took over a **billion** years of oxygen production for oxygen levels to reach 0.1 (which corresponds to the atmosphere being 10% oxygen). Stages 2 and 3 in that graph are important to note - those are the periods during which the sea and then the land are absorbing oxygen. It is only once both the oceans and the land are fully saturated that oxygen levels are really able to increase.
Here's something else that's interesting - [plants need oxygen to live](https://www.gardeningknowhow.com/garden-how-to/info/can-plants-live-without-oxygen.htm). If you took an absurd amount of seeds (of grasses, trees, and everything really), and planted them on a barren planet that's in a star's habitable zone, they would die due to a lack of oxygen. Same thing if you took the effort to place already-grown plants. They are net producers of oxygen, but at times (such as during the night), they consume more oxygen than they produce. The oxygen they produce would be absorbed by the land around them, leaving none for them at night when they will need it to survive.
Don't forget that most plants also need soil, which a barren planet doesn't have. Soil is a mixture of minerals and organic material, and that organic material has to come from somewhere. It's not unreasonable to assume that a civilization capable of travelling to a new planet would have enough bio-engineering capability to produce plants that can start the process of soil production, but it's also likely that those plants aren't what they would want to have as the final product for growth on the planet.
So the *easiest* planet to terraform would be one that already has plenty of oxygen and soil. It's probably what Earth looked like right around the time that life started to leave the oceans.
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Depending on the amount of earth creatures you intend to import to the planet later, there should be seasonal weather changes, a slowly orbiting moon close enough to induce tides, a magnetic core, lots of water to moderate the days, a yellow sun like our own sun ready to power chloroplast filled life.
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My early 20th Century (ww1/interwar/early ww2) alternate world has armoured airships (I haven't fully worked out the physics but I assume some sort of handwavium to allow armoured ships not just zeppelins).
**Would 'wet navy' i.e. traditional ships, still be needed?**
*edited to update to reflect comments*
thanks all
Assume very similar to early 20th century tech expect flying warships. i was assuming more flying airships than 'ships' that fly. i am assuming that traditional ships still exist for bulk trade but i suppose that air freighters/liners may overtake for high value/low weight traffic.
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# YES
The air fortresses use armored underbellies and a deliberate all-or-nothing armor scheme that is set out in such a way that if shot at from below many many of the nacelles need to be damaged to force the airship to the ground - or water.
### Most Cargo has bad stowage to transport fee ratio
While airships will be a good way to transport light cargo with high revenue rates fast (like mail, where a few grams with tiny volume earn a considerable fee), most other cargo has really bad ratios for $\frac {Weight \times Volume}{Fee}$. Even fragile material like *porcelain* is more economic to be transported by water!
Also, did you know that they had to develop special extra light porcelain for the Hindenburg because normal porcelain would have been too heavy?
### Wet Navy supplies the Air Navy
Thing is, that these airships still need fuel, and shipping fuel is easiest and most efficient on the waves. The airships fly to rendezvous with oilers and supply ships, which also act as radio beacons.
### Wet Navy offers SAR
The Air Navy is still somewhat fragile, and to support them, it is best to have dedicated, fast and mobile ships that go out and pick up the survivors from crashes. These SAR vessels are, due to a lot of the planet being water, of course water-bound and operate out of the support flotillas that act as waystations for the Air Navy.
### Wet Navy has a lower profile
Compare the radar profile of an aircraft carrier to a flying aircraft of its size and you will realize one thing: To *see* the ship, it needs to be above your horion. A Japanese Flattop like [Ryūjō](https://en.wikipedia.org/wiki/Japanese_aircraft_carrier_Ry%C5%ABj%C5%8D) has only a height of about 15 meters over the waterline. Assuming you are a radio station mounted on a similar height, the tangent to earth that allows you to see her is about 19.5 kilometers.
[](https://i.stack.imgur.com/Hzl39.png)
However, would that be a 15-meter aircraft flying with its belly at 200 meters height (Hindenburg's cruise altitude), the flattop can see the airspip appear over the horizon at 46.75 kilometers.
[](https://i.stack.imgur.com/Cc1jw.png)
If both are flying, and have their bellies at 200 meters, then the spotter on top of them can see the other spotter on 74 kilometers.
[](https://i.stack.imgur.com/cCLSB.png)
So in effect, the smaller surface ships can get *much* closer to the enemy fleet before being detected.
### Wet Navy has more Dakka
You can armor the airships, but you need to place much much more guns to fight of fighter aircraft as well as surface air defence. Surface ships only need to mount more and more anti-air guns because weight is not as much at a premium as in airships and you only need to put them on the upside, not 360° around the ship.
The Development might possibly forgo part of the development of aval artillery to 16' guns for many more fast firing multipurpose guns from the getgo, though I can see Yamato and Musashi engaging airships at about eight to ten nautical miles with their 46 cm [Type 3 anti-air shells](https://en.wikipedia.org/wiki/San_Shiki_(anti-aircraft_shell)) - while ineffective against bombers, against lumbering airships enveloping them in flaming shrapnel will prevent fighter launches effectively and might damage engines or rip crew off the walkways.
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Yes there would still be a need for a wet navy.
For example an armored airship needs to be build to deal with enemies above, on the same level and below it so it needs guns facing everything. A battleship only needs to fire above and on the same level, which simplifies the design to "guns on top".
While theoretically such armored airships would be able to reach high speeds especially when using jetstreams high in the air (hindenburg did 130km/h without) the time to accelerate and decelerate would be bigger than the wet navy ships. So a wet navy would be able to react faster to changing conditions while a well-prepared airship raid could catch up and do its business quickly.
While modern tech lets us use airships without mooring masts and many people to land them we did in WWII. Technically you could cut down on time to bring in logistis because you dont need to land in the harbor but can land close to the target destination instead, but supporting it with traditional wet navy logistics is likely a good plan.
That said these things would be GOOD. A battle-airship flying at a few hundred meters would have more range than its water based counterparts, its harder to adjust aim when firing at these airships since you cant use the water spray to judge the missed distance (and good radar controlled weapons werent available), missile technology was less capable than torpedo's so its only vulnerable to other large caliber rounds, they would be able to function as artillery platforms above land and not be limited to the sea... but they wouldnt replace the wet navy.
Edit:
Also although its been beaten to death, an aerial aircraft carrier could easily support your aircraft. Unlike the depictions in media or the use of the real-life Acheron aircraft carrier you could go up to a certain height and simply drop the aircraft down to launch them. This decreases the need for steam catapults and the risk of the aircraft crashing into the sea. Also in WWII climbing to the correct height was a time consuming task. Being launched high above the sea (or land!) is a great advantage. It also makes it possible to launch and land aircraft at the same time pre-modern aircraft.
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This question can be answered simply, based purely on the difference in density between air and water.
For any specific displacement, a water ship can carry 200x as much armament and/or cargo as an equivalent ship in the air. Unless you have anti-grav tech, then there are numerous areas where it isn't possible for the air ships to outperform the water ships.
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In all likelyhood, the answer is **"Yes, definitely"**, though it depends slightly on the nature of your handwavium.
While airships hold many advantages over a traditional Navy, matching the sheer bulk and durability of seagoing vessles requires a lot of handwaving. Like a lot a lot.
Let's look at a few aspects that might give some idea of just how much handwaving is required:
**Weight**
The Hindenburg's empty weight was around 120 tons. A Queen Elizabeth class Battleship displaces around 33.000 tons of water. So you're looking at a difference in weight of a factor of roundabout 275, give or take. If you want your airships to perform similarly to the Battleships, they are likely going to require similar levels of weight. In the real world, airborne units faced much lighter guns than Battleships did (obviously), if we assume flying battleships we must assume them fielding battleship size firepower. These airships would also be large enough (and probably slow enough) for large caliber, land based Artillery to realistically hit them, directly. Armoring against that is very, very heavy, and requires a lot of handwaving.
**Logistics**
While the Navies in the mentioned time period fought very flashy battles with dozens of capital ships and hundreds of smaller vessels, a very important task of Navies in warfare is related to logistics. Britan required a constant supply of resources brought in via ship, which was why the u-boat campaigns were so damaging to them. To take over all of this transporting duty would require a lot of airships. They would have to be incredibly 'cheap' to build in order to fill this role entirely, hardly any more expensive than a comparable ship in terms of carrying capacity.
Also, loading and unloading an airship is likely going to be much slower than a ship, though if you handwave enough they'll be able to 'land' properly, which might remedy this somewhat.
**Weather**
Storms on the high seas are a danger for seagoing vessels even to this day. During the world wars, they caused significant casualties. Airships would be much more vulnurable to adverse weather, and being able to operate in rougher, stormier conditions is something that would be a definite advantage of seagoing ships.
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**Propulsion**.
These airships are great - some kind of antigrav lets them float in the air despite armor plate. Literal lead zeppelins (well, steel perhaps). And they can go downwind quite fast.
Problem: they still can only propel themselves with fans, despite their massive inertia. The war is over before they get there. So somebody needs to *lead* your lead zeppelins.
So the zeppelin drops a line and a high-speed tugboat snags it as it drives past. The zeppelin is jerked into motion like a parasailer (parasailor?). It can veer far side to side, or swoop down and momentarily shut off its antigrav for immense crushing force, while its nimble tug dodges enemy artillery for dear life.
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# My pirate safe haven runs gambling rings, [horse races](https://worldbuilding.stackexchange.com/questions/224514/illegal-steampunk-horse-racing-after-the-apocalypse-what-format-is-most-profita), and trades contraband but no one can find it or penetrate it. Why?
I've got a story revolving around [pirates and a rescue](https://worldbuilding.stackexchange.com/questions/224843/why-did-the-pirates-deaf-prisoner-get-a-secret-message-without-being-detected). The pirates have a large organization and hide in a haven like the Barbary Coast. In addition to [piracy](/questions/tagged/piracy "show questions tagged 'piracy'"), they bring in rich people to gamble and run numbers, [do many corrupt activities](https://worldbuilding.stackexchange.com/questions/225501/how-can-this-prison-induce-stockholm-syndrome). But the location remains in an uncharted region.
I want the haven protected from being found out, and from being overrun if they are found out.
The world is unique. It is post-apocalyptic steampunk, [with a single government per this question](https://worldbuilding.stackexchange.com/questions/225198/what-would-fit-in-a-heterogenous-government-reforming-their-post-apocalyptic-wor), and there is no sky, so celestial navigation is out. The region is [dessert wastes of an alien planet](https://worldbuilding.stackexchange.com/questions/183710/how-could-we-modern-humans-colonize-a-hot-planet), so landmark navigation is out. Civilized society uses radio beacons and lighthouses to navigate. There are no lighthouses marking the areas by the haven. So, [keeping hidden is pretty easy so far](https://worldbuilding.stackexchange.com/questions/225180/how-do-i-create-a-secret-steampunk-navigation-scheme). But:
**Trading/Gambling:** The pirates run [many money making schemes such as horse racing, playing numbers](https://worldbuilding.stackexchange.com/questions/224514/illegal-steampunk-horse-racing-after-the-apocalypse-what-format-is-most-profita), casinos, and dealing contraband. So civilian crew are reaching the haven; the pirates only allow you in if you let them pilot your ship, and your crew stays below. No one gets to see how they got there.
Generally, the pirates can feel safe with this arrangement, but the Captain is paranoid. It's a matter of time before some large navy comes rolling in to try to shut them down. Relying on hiding alone won't do.
# Why wouldn't a small navy be able to penetrate the haven?
I need to lay the haven's defense perimeter out in a way that protects them from a sneak attack by a single [small navy of the civilization](https://worldbuilding.stackexchange.com/questions/225198/what-would-fit-in-a-heterogenous-government-reforming-their-post-apocalyptic-wor), which consists of five [well-organized and maintained cities](https://worldbuilding.stackexchange.com/questions/224426/replacing-heavy-cranes-with-airships-for-alien-city-building-pros-cons). I originally went with a walled fortress, but that stopped making sense because it's so easy to spot from a distance. Then I got stuck, and this question came up.
## Technology:
The world is 19th century tech in a post-apocalyptic wasteland. Food supplies don't exist outside artificial habitats like cities or this haven, so time on a ship has serious logistic limitations. Fuel is everywhere however, ore is mined and it reacts with the toxic air to release plenty of energy. This powers everything from their engines to their air conditioning, and electricity.
## The navy:
It is steampunk, all ships are airships. There are no seas.
If attacked the navy would be using small, quick frigates [with light guns designed mostly for ship-to-ship battles](https://worldbuilding.stackexchange.com/questions/224647/airship-combat-in-dense-atmosphere-what-charge-for-26-lb-cannons). They would bring [a couple "long tom" big guns](https://worldbuilding.stackexchange.com/questions/224665/maximum-effective-range-for-a-modified-long-tom-cannon-in-high-density), which could do a lot of damage to only a few targets (they have to choose wisely). They would be so far away from support that a battle could not last more than 3 days realistically. That would only change if the navy dragged out a floating battery or resupply ship; which would quickly become targets they would need to defend. Generally not a net benefit.
## Pirate Defenses:
**Pirate ships** are evenly matched with the navy; mostly frigates. There will be fewer of them and crews will be not as well trained in naval combat. So [the haven needs to offer support](https://worldbuilding.stackexchange.com/questions/225212/how-to-maintain-large-ships-in-hostile-atmosphere).
**Cannons** can be mounted on turrets or towers. Big cannons are slow to load and slow to aim, difficult to hit a running frigate. But they are the only thing with stopping power because smaller weapons don't do much damage to gas bags. A well-placed cannon round can knock out a whole section of the gas bag, and it has a medium range of effectiveness.
**Trebuchet** has multiple sharp spears that hope to break windows and contaminate an intruder ship. Very short range and the shot scatters randomly.
**Fouling shot** has a long length of cable wadded into a cannon. It spreads out in the air and hopes to foul any ship screws or engines. Really just luck, you can't aim one. But a fouled ship is a sitting duck.
**Walls** have limited use except in the event of some ground vehicle attack. Anything like this would need to have the vehicles carried in by airship because there is little hope of crossing the wastes. Walls can reduce the effective range of long range weapons, and prevent ships from targeting whatever is behind them.
**Camouflage** would only be effective in hills or low mountains. The only way to hide in the barren wastes would be to look like a mountain. Or a big rock. They don't have the tech for big cammo; or at least, finding a real set of hills would be cheaper (and cheap is good for greedy people)
**Lookout towers** can be manned, but it's horrible work, and the guy you send there will likely be unreliable. Probably something you just leave empty until an attack is suspected. They can radio signal back to the haven.
## How do the pirates use these tools to defend their haven?
A good answer roughly paints a perimeter with these tools that a small navy won't get through. The answer is a worldbuilding answer, so limitations on the navy beyond what I gave are fair game. However, the assumption is that a small navy *can* reach the haven and carry out a battle for three days, but **What enables them to hold off the navy?**
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I think the answer is hidden in your setting as you've explained it. The fact that there is no visible sky will, I think, severely limit how air travel is done. The pirates won't need to defend themselves; they just need to be far enough out of reach that no one else could find them without already knowing their exact location.
To travel long distances, a ship needs to be able to know where it is, how fast it is going, and what direction it is pointed in. This generally requires comparison with a fixed point - and for real life sailors in history, almost all of these were found in the sky. The obvious ones are the stars, but the sun was also very important. A major technological leap in naval navigation happened when a clock was invented that would keep time while at sea. By comparing the time on the clock with the local time indicated by the sun overhead, pilots and navigators could better identify their position, and were able to sail more complicated routes as a result.
I am assuming, from 'there is no sky', that the sun's position is not immediately obvious. This will remove vital positioning information, and likely reduce travel to a handful of known routes. The most commonly used routes are probably going to have to pass by some kind of largely visible landmark that navigators can compare their position to in order to know if they are on course to reach their destination before running out of supplies. However, a few routes will exist simply because the pilots know the measurements. Suppose there are two cities with no major landmarks between them - if the distance over land is a known quantity, a flight plan can be made between the two objects to fly for that distance in that direction, using machines like a clock and compass to try and keep on course. Another way that a route might be set would be to create landmarks to give pilots the information they need. This could be as simple as giant mile markers propped up out of the land, or complex structures like lighthouses or semaphore towers that send detailed information to ships about how to manipulate their vessels to arrive safely at their destination. Still, these routes, once made, would be set in stone, and most ships would only travel along set paths around these landmarks, leaving a lot of blank space on the map.
Radio technology will solve some of these problems, and probably be what the navy uses. Rudimentary radio scanning might allow for limited exploration, but mostly, the use of radio will still rely on infrastructure - radio towers, emitting on specific frequencies, would provide a fixed point to ships with radio receivers, allowing them access to the information they need in order to travel safely. This may expand the routes beyond the use of visible landmarks, but it still has its limits and and its blind spots.
The other issue with radio is that it is extremely easy to jam. Beyond the pirates, if there are any factional disputes in this world, say cities or nations that are or have been at war, or merchant groups that are in competition, relying on radio would make you extremely vulnerable to opponents. Air routes that stayed close to permanent landmarks that could act as back up if your guidance frequencies got jammed would probably be a necessity.
So, all the pirates need is for their location to be out of sight of any normal air routes, and maybe to be constantly jamming radio frequencies. An actual island would be perfect - travel over water in conditions as you've described them would be very difficult. However, any desert, unmarked flat land, or homogeneous forest/swamp would also provide a large area which airships would treat as a dead zone and not fly over. As long as it isn't near a mountain or other obvious landmark, this alone would make it more or less impossible to find; I'm assuming that ships are expensive to maintain, so people won't be taking risks with them - they'll stick to known air paths where they know the distances and landmarks to sail by. Even the navy would think twice before sailing into uncharted territory, especially if their radio communications were compromised in that area.
All that remains is for the pirates to be able to reach their location when no one else can. This may simply be a matter of them knowing the actual exact location, and doing the math to know how long to travel and in what direction. It can also be the case that there is one secret radio frequency, probably changed on a regular basis, that broadcasts clearly from the base while all other frequencies are jammed. The pirates tune in to that frequency and sail towards it. You can also give them access to older sailing techniques - maybe they are on a firm north/south location, and use a compass when nobody else does anymore, or maybe they know that, with the right kind of telescope, you can actually see the stars, and they guide by those. All you really need is one fixed point to compare themselves with, a piece of information they have access to which tells them where their ship is, how fast it is traveling, and in what direction. As long as the navy doesn't have that information, they won't sail into uncharted areas.
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The problem is in having one location that can be attacked. Pirates work best when nobody knows where they are based.
Instead of having one base, have a multitude of locations that coordinate. Horse racing is one place. Casinos are spread out over multiple places. Contraband never is collected into one warehouse. The navy has a very difficult time dealing with a diffuse enemy. It knows how to put massive power against one place. This is why smuggling has always occurred - the navy can't defend a long coast against small boats.
So, the politicians trying to change people's behavior will send the navy against one casino and boast about its destruction while the pirates will simply keep running the rest of the casinos (which will collect enough money to build more). The destruction of one will allow you to raise the percentage that the casinos collect.
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I don’t think the outward defenses are what really matter for keeping this place hidden. The most important things to consider are Money, Misdirection, and Mobility.
**Money**
These pirates are running a gambling business, correct? So they have control over some extremely rich people who probably owe them a lot of favors. I would imagine many of those people would have enough influence to have an impact on this navy.
For example, a high-ranking member of the navy could be deep in debt to this gambling ring. Because of that, he has a vested interest in keeping this place a secret. He gives the illusion that he is helping by giving the crew fake directions.
“What? The pirates weren’t there. How strange!”
“What? The pirates escaped because they knew exactly when we were coming. How unfortunate!”
The pirates are rich enough that they can probably afford to have inside men. If they have powerful enough people in their corner, then they don’t even have to worry about getting caught. The navy might be on their side.
There’s also bribery, which can buy loyalty pretty quickly. Wave some gold coins in front of these navy people and they’ll probably shut up pretty quickly, and pretend they never saw a thing.
Money can also buy good weapons and strong warriors. Buy some ruthless mercenaries and these navy fellows might be walking into certain death.
**Misdirection**
If the pirates have spies inside this navy, like people they have bribed or corrupt officials that are deep in debt due to gambling addiction, then the pirates can easily give people the wrong location.
If I was trying to hide a secret base, I’d have multiple backup bases with multiple decoys.
Basically, have one place that’s more or less operating in plain sight. It’s not exactly public knowledge, but there are enough people who know about it that the navy knows it exists. The navy busts it, wipes their hands clean and say “Well, the pirates are all eliminated. We can go home now.”
In reality, that place was only a decoy, so the real base is hiding somewhere else, operating perfectly fine.
The best way to protect a secret is by putting a lot of red herrings in the way of the truth. Lure the navy into a false sense of security by getting some inside men and feeding them false directions.
When they reach the decoy base, you can set an ambush for them, like rigging the whole place to explode or burn down, or you can just have a bunch of actors hold their hands up and say “Oh no, you caught us. We will never recover from this defeat.” All while the pirate leader is sitting in his real base sipping expensive wine as his rich donors gamble themselves further into debt.
**Mobility**
The secret base needs to be constantly on the move. Have the pirates be trained to set up shop anywhere, any place, any time. In rain or shine, cold or heat. The pirates are used to busts, and they have an early warning system to get up and leave as fast as possible. They’re trained to not say a word if they are caught, and they are also trained to scatter in all directions and regroup at the secret location as soon as someone sounds the alarm.
Rather than having one location, I am imagining this base being a nomadic camp that is constantly on the move. Everything in this place is made to be dismantled and put back together as fast as physically possible. It would almost be like a traveling circus, with a bunch of tents they can easily set up, and gambling games that are also easy to set up. The camp is self-sufficient and constantly on the move, never staying in one location for long to avoid detection. Everyone is sworn to secrecy. The only people allowed in have to have a special invitation and know a password. The only people who learn the location for the next setup will be the rich investors and people who pay for this knowledge.
This place needs to be super adaptable, prepared for anything that the navy can throw at them.
They don’t care about fighting. They’re pirates. The only thing that matters to them is survival and money. They’re not going to stay and fight, their philosophy is “run away to see another day”.
Also, why not have the base be on a massive pirate ship? A constantly moving ship which never stays in one place for long sounds like the perfect base of operations. It’s speed is what keeps it away from detection. You could even combine the ideas by having both bases. The pirates have one massive ship AND a constantly moving nomad camp. That way they can conquer both land and air.
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**The secret ingredient is danger.**
The danger can be **nature**(fauna or flora), **topography**, **weather** or a combinaison of all three.
The haven has to be placed somewhere really dangerous, where pirates knows **how to deal with the danger**, knows **secret entrances** and knows **the code to not be attacked by defensors**.
The Navy doesn't have those informations, their only valid tactics would be to use a trojan horse or create discord inside the haven. You can find solutions to those tactics.
The Navy can't siege the place because it's dangerous out there, and can't peacefully find supplies.
You need people to run the Haven, defending it, producting food and fuel, proposing accomodations, confort and maybe pleasures ;)
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## The Base is Underground
### How it solves your hiding problem:
By being underground you can make a large based very hard to find. Since all people live in artificial habitats, this is already not much of a handwave since underground bunkers are already a staple of post apocalyptic worlds like this. The trick to hiding while still being findable will be to use natural signals instead of man-made ones.
The area of the desert where the pirates live could be rich in naturally magnetic or radioactive ores; so, instead of following beacons, the pirate navigators would follow variations in these natural emissions. To a casual observer, it's just normal rock, but if you turn up the sensitivity on your beacon tracking navigation equipment, it is as good as any map... you just need to know where you are going.
Furthermore a lot of natural electromagnetic activity in the area could help to interfere with communications which would make espionage more difficult since they would be cut off from easy radio communications.
### How it solves your defense problem:
The pirates could not outgun a proper military fleet, but they don't have too. Their whole base is basically a nuclear bomb shelter; so, all those ship to ship guns, would be utterly useless. The navy could try to use their artillery to collapse the entrance, but this is no big deal, the pirates expect this to happen and have the excavation equipment and reserve of supplies needed to wait out the fleet and just dig their way out when done.
This leaves the navy with only 1 option: send in ground troops. While the backing of a national government's economy can ensure that a proper navy can outgun any private fleet, small arms are a different story. Compared to warships, rifles and revolvers are dirt cheap; so, for the price of just a few ship-to-ship cannons, the pirates could arm every man, woman, and child inside their base against the navy's ground forces. In the 19th century, the firearms used by militaries, and those used by civilians were one-and-the-same, and in a town of pirates, you can expect your average "civilian" to be relatively good with one. So forcing a ground war will do a lot to level the odds.
Furthermore, this is not going to be an open battlefield for the navy troops. Attacking an underground bunker means that you have to get passed choke points, murder holes, and any other nasty surprises the pirate have put in your way. Without the advantage of modern infiltration tools like smoke bombs, tear gas, flashbangs, etc., the navy ground forces would be at a huge disadvantage and would need a significant numerical advantage and a ton of bravado just to get through the front door.
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## Flying Castle
Since this is a Steampunk world, your Haven is a flying fortress. The pirates have used their ill-gotten gains to build a ship that's so large, its ceased to be a vessel and become a floating citadel. Horse races occur in the courtyard, gambling in the towers, etc.
The pirates could deviate from a traditional castle structure but still use the terms for flavor if you'd like.
Like Google's project Loon, it's too expensive to use engines to control Haven's motion, so it mainly drifts. It changes altitude to take advantage of the wind moving in different directions at different heights, but otherwise it just travels where it travels.
## Location
Haven puts out a coded radio message. If you know the code, it directs you to Haven's current location. If not, it's just gibberish. The code changes periodically, and if you've dropped out of the favor, Haven's representatives will not give you the new code.
## Defenses
It's a flying castle. It's got thick walls, cannons, and the pirate fleet to defend it.
Maybe it can also break apart into smaller craft - the Courtyard falls to the earth below, but each Tower turns out to be a Battleship! Some parts of Haven flee, while others fight to buy time.
## Betrayal!
The Navy can find Haven either because they decrypt the radio message themselves, or because someone gives them to key.
The nice thing about this setup is: if Haven survives the initial assault, they can continue to operate - the pirates change the code, re-build Haven, and start over.
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**Range, Wind, and War Kites**
There is a limit to how large a gun you can put on an airship, especially since after a certain point, you can't mount a gun because it'll blow itself out of its own mooring. That means that land-based defenses can *always* outrange frigates. If the pirates have defenses and manage to create a few land batteries, that means that any frigate will have to fly through an arsenal of flack first.
Now, *normally* this wouldn't be so much of a problem. Air has three dimensions and long range cannons aren't exactly accurate. Which is why the pirates did something rather clever - they built their base near geological structures (i.e., inside a mountain range) that has wind patterns which force ships towards a particular flight path. An incoming army will need to brave flak and winds shoving them into said flack.
You can also supplement this with spiked war kites. If the ships are going to go with the winds, the guns get them. If they go *against* the winds, the pirates launch war kites, viciously spiked kites that tear through sails and gas envelopes and get blown into the ships through the wind. Very terrifying.
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Two ideas come to my mind:
**1. The pirate haven is actually a huge mobile fortress**
Be it a huge ship or a floating building, the locations is in constant movement, and only the pirates know its itinerary. That way it's really hard to find without knowing where it will be, and this ship/building can also carry everything it needs to defend itself.
**2. The way to access the place changes with the weather/seasons**
The pirates found a place that has different ways to be accessed (both by sea and land), but most of these paths become innaccesible when the weather changes. Rain floods most of the land paths and make the surrounding sea unviable to sail, but a specific, intrincated path is still able to be used. Spring/Summer could make certain dangeorous flora and fauna populate most of the land around this place, so sea is the most viable way in; and so on and so forth. The pirates are very aware of all these changes, so they know how to access depending on the weather.
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**The pirate casino is on a navy base.**
The small navy will not get through. It is already there. The people who run this particular base are in cahoots with the pirates. The base is big and the pirate activities take place in a "disused" area with older ships in storage, hulks kept for salvage, weapons practice ranges and the like. Fancy ships from customers are kept out of sight in hidden docks. Navy personnel based elsewhere who are visiting have no reason to go to that part of the base.
Pirates have more to worry about than navy. They need to worry about other pirates coming to get their stuff! There are rich people betting money here! There are loads of contraband and proceeds from selling it. Being on a navy base is great for that. If other criminal groups want to come get their stuff they have the navy to contend with.
Using a military base as a base of criminal operations is not a radically new idea.
Persons living on the base pretty much know what the pirates are up to. And the pirates make sure visitors from the base get special rates and have a good time. Of course the military commanders and other officers profit from the scheme.
The loser is the civilian government who does not get tax proceeds from pirate activities and cannot stop illegal activities undertaken by the pirates.
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You said that customers can't get to the haven without a pirate captain pilot. This is essentially like modern ports, where there is a pilot supplied to each large ship that wishes to dock, but obviously in the reverse direction.
You also said that navigation is being done by radio beacons.
# Solution: Coded Beacons
So a solution could be that there are "good" beacons and "bad" beacons, potentially used in a sequence or are only "on" for a predetermined time. So the pirate pilot knows when to watch for/pay attention to certain beacons and when to ignore them depending on the time of day or day of month. This allows for installation of simple beacons that are activated in a timed manner (i.e. Easy to program and Re-program), but unless you "know the code" of what and how to follow them you will never end up at the haven.
This also fits in well with your available technology, as it can be setup with a simple clock and calendar to turn on/off beacons in a fixed manner. It's also cheap to build and maintain, and doesn't require experts in each beacon's location.
If you couple this with the answer from @headax (Danger/Boobytraps) and with
@Nosajimiki's Underground locations, you've got a pretty resistant setup.
If a location only opens its doors for a predetermined time range on specific dates (e.g. 1-2, 6-8 on Tues/Thurs, 3-4, 9-10 Mon/Wed/Sat) , then even if someone arrives in the correct location, they won't see an open door and will assume it's the wrong location or they got lost. If the people operating the doors don't open them when a ship was too early (i.e. They don't know the schedule), or didn't broadcast a light signal properly, that adds to the safety for the haven.
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# Mountainside funneling, turret defense, and temperature venting
While a walled fortress makes it easy to spot, but if you start the "Wall" of it rather far away from the center of the hidden base, then you could start utilizing that terrain advantage to force them into specific approaches.
If you add a few airship sized tunnels through the mountains for quicker access in and out, you can force them to enter one at a time, and funnel their numbers down.
Once you make safe passageways, you can essentially guard those a bit better with cannons, or cannons aimed at anyone entering through that passageway, or partroling ships on the inside of the mountains - numbers mean nothing if you have to fight your enemy one at a time.
This does run into the issue that, to an extent, ships can fly higher and above these barriers, but providing enough of them, and by potentially turning them into your mining operations and venting the heat out above will help reduce air temperature - strategic use of that could cause "No Fly Zones" by effectively making them harder to fly through - and this could be used in-between mountain range gaps as well to force them to take specific paths - which would reduce the amount of aiming a cannon would need to do to catch them - you could lead your shots based on where the air currents will naturally take them, or where they'll naturally aim towards to get out safely.
Once you do that, it's a matter of setting up potential cannon turrets aimed at these various corridors, and you've got secured entrances that means that you don't need a *given* cannon to take down a ship - any number of them can work, and take them down slowly.
Basically, the pirates are set up in such a way that it's basically Switzerland mixed Pirates of the Caribbean: At World's End's Shipwreck Cove.
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Fun question. It's hard to answer though because some of these things can't happen together easily. Pirates almost never existed alone. They were mostly sponsored by a nation waging war on another since it's nearly impossible to provision a ship without a nation's resources. This is especially true for weapons/quality powder/projectiles which were tightly controlled.
However, assume that you now have a city/base that the rich are visiting often enough for it to be a going concern. YOU ARE NOT A PIRATE ANYMORE. You are a businessman/merchant. You have employees/retainers/merchants/craftsmen. A pirate with a peg leg, eye patch, parrot on his shoulder is not running the dice table. He's not serving the type of food that the rich will eat.
As for being hidden, that doesn't really work. If the rich can find you, then so can your enemies who tend to be the same type of rich. A large part of the skirmishes were just your competitors stamping out the competition.
Lastly, if you can defend yourself, why hide? And if you can defend your slice of civilization, you definitely are NOT a pirate. You, at the very least, are a city/state and a fairly successful one. One last point is that virtually no wooden sailing vessels were successfully defeated by cannon fire. It took boarding action.
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**The Pirate Safe Haven is too small to 'see' normally.**
The Pirate Safe Haven is physically too small to be detectable by normal means, i.e. it is microscopic, and its visitors are also proportionately sized while they are present. It could be anywhere, and it wouldn't matter.
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In the new *Thrawn* books by Timothy Zhan, he describes a weapon called a 'breacher missile'. In simple terms it is a missile that sprays a corrosive chemical onto an enemy ship or structure, damaging external equipment like sensors and weapons and creating weak areas for laser weapons to target. The advantage (as described) over more traditional explosive based weapons is that they are hard to defend against. Even if the opponent manages to destroy the missile, the corrosive liquid inside is going to continue in whatever direction it was traveling.
While Star Wars is pretty loose with science, it got me thinking. Could a weapon like this actually work in a more realistic setting? Are there any known chemicals that are sufficiently corrosive to rapidly damage or destroy a target? How would you make those chemicals remain effective in the low temperature, low pressure, high radiation environment of outer space?
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In space? Yep! You can rapidly damage or destroy a target by the simple act of accelerating *any* chemical to high enough velocities and crashing it into an opponent. Start at a few kilometres per second relative to the target, and go up from there as necessary.
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Oh. Corrosion is generally slow, and even if it *were* a particularly rapid process, it is limited by the amount of corrosive material which gets used up in the process). A kinetic weapon is instead limited by both the amount of material *and* the velocity it is travelling when it hits you.
I also rather suspect that you get a lot more literal bang-for-your-buck by using chemistry to generate kinetic energy (eg. fragmentation warheads) than you do by trying to nibble away your opponent, but I don't think I can easily prove that.
If nothing else, it is always potentially possible to fire a bullet a bit faster, but you'll have a hard job making your super-acid correspondingly more corrosive because there's only so much energy you can pack into merely chemical bonds.
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Its a setting where normal rules of physics don't apply, so its hard to translate its stuff into the real world. If you wanted it to work in your setting, then you can wave your hands as you see fit.
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I'll suggest using [FOOF](https://en.wikipedia.org/wiki/Dioxygen_difluoride) and then back away very quickly. That stuff is so dangerous I don't even like to *[read](https://www.science.org/content/blog-post/things-i-won-t-work-dioxygen-difluoride)* about it for fear of getting burned.
FOOF is horribly unstable but can be weaponised by using relatively stable precursors and mixing them on contact or on a proximity fuse to dust an oncoming space craft with particles before they spontaneously decompose. In the case of the breacher either it detonates a cloud of FOOF in close proximity and the ship gets randomly hit by active molecules as it flies through or the breacher latches on and sprays concentrated FOOF onto a given area of the hull.
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More than corrosion you can try with ablation: basically you can try to sandblast the surface of the target spaceship with a constant flow of abrasive particles at high velocity.
If you send it against the ship velocity you can use the addition velocity principle at your advantage.
Additionally, if you can reach relativistic velocities, the particles will produce gamma rays, which are pretty effective at eating matters away.
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**What is the spaceship made out of?**
If your space ship is a flying steel battleship, the prospect of corrosives eating the hull is slim. But you could definitely have carbon fiber spaceships, or plastic space ships, or [styrofoam space ships](https://worldbuilding.stackexchange.com/questions/79070/what-material-to-use-for-a-near-future-armoured-spaceship/79099#79099) or [ice hull](https://worldbuilding.stackexchange.com/questions/115471/feasibility-of-spacecraft-constructed-from-ice) spaceships that would be very much affected by corrosives. Your corrosive of choice would depend on the material you were attacking. Solvents could work for plastic. Oxidizers for carbon fiber (hydrofluoric acid! there is your corrosive). Maybe sodium metal powder in hexane for ice hull. [Hot mercury vs an aluminum hull](https://www.youtube.com/watch?v=Z7Ilxsu-JlY) - that would be a fun scene to write as the fingers of amalgam start sticking into the interior of the ship.
**A universal "corrosive" would be antimatter**. You could "spray" charged antiprotons in a beam, confine them in a missile or what have you. [The energy released by the matter-antimatter reaction depends on the relative velocity of the reacting particles](https://www.fnal.gov/pub/science/inquiring/questions/antimatter1.html) so you could dial it up or down depending on your needs, which is cool for a fiction. This might be a more effective weaponization of antimatter in space - if you blow it up like a bomb antimatter offers no advantage over a fission bomb. But using antimatter to react away a piece of the hull is less destructive and offers the possibility of capturing the ship and crew intact.
OK, relatively intact.
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Here are a few candidate compounds we have available today (rounding up a few of my comments.
One of the most obvious is **Chlorine Trifluoride** (ClF3)](<https://en.wikipedia.org/wiki/Chlorine_trifluoride>). It has niche uses in semiconductor manufacturing and was proposed as a rocket oxidiser. One of the researchers working with it, [John D. Clark](https://en.wikipedia.org/wiki/John_Drury_Clark) describes ClF3 as follows:
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in his book *Ignition! An Informal History of Liquid Rocket Propellants* (which is worth a read)\*
So ClF3, in contact with almost any material, will start a fire; it's the oxidiser so there's no need for air. Even glass spontaneously combusts in contact with it. The exceptions are metal fluorides, which make it possible to contain by using them as tank liners. It has a boiling point below room temperature and a fairly high vapour pressure, so would be expected to be gaseous by the time it made contact. This is ideal if you want it to degrade the hull rather than anything more dramatic (though in sufficient quantities dramatic is possible, as described [here](https://www.science.org/content/blog-post/sand-won-t-save-you-time) and especially in the link about a spillage. Note that a major reaction product in many cases is HF, which is nasty enough by itself (corrosive and poisonous).
As I commented, we also have [**Oxyacids**](https://en.wikipedia.org/wiki/Oxyacid) such as [Chloric acid (HClO3)](https://en.wikipedia.org/wiki/Chloric_acid) and [Peroxymonosulfuric acid (H2SO5)](https://en.wikipedia.org/wiki/Peroxymonosulfuric_acid) which would be useful against organic materials such as composite hulls as well as some metals. Even [Piranha solution](https://en.wikipedia.org/wiki/Piranha_solution) (sulphuric acid and hydrogen peroxide, mixed just before use) would attack composites.
I suggest though that **with laser weapons commonplace, mirrored hulls** would be used to provide some limited last-ditch protection. Rather than metal these could be dielectric mirrors (usually oxide material) so ClF3 would be ideal. Burning off the mirror coating would be just what was needed to make the hull more vulnerable.
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\* John D Clarke was also a published SF author and Isaac Asimov's boss for a while; Asimov wrote the foreword to *Ignition!*
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## Chaff
When you start talking about civilizations with propulsion capable of interstellar flight, you are also talking about people with incredibly powerful weapons thanks to the [Kzinti Lesson](https://larryniven.net/kzin/worlds.shtml) principle. So, it is unreasonable to think that any ship would survive and attack from any weapon based on the chemical bonds of solid matter alone.
Instead you are not attacking the ships armor, but its active defense systems which constitute 99.999% of the ship's ability to survive a weapon hit. So, a damage-over-time weapon would not be something designed to corrode the hull, but something that can trick the ship into wasting power/ammunition defending against feigned attacks.
This is where chaff comes in. Chaff are cheap little pieces of radar reflective tape designed to fool sensors. So you fire a missile at the enemy and before it gets into range of the active defenses it starts scattering a large cloud of chaff. As the chaff tumbles its cross section is constantly changing making it very hard to tell where any one strip is or even what they are; so, the defending ship has to activate its shields to cover a large time period and area of uncertainty until it is sure that there are no more possible inbound impactors, or that it is clear of the chaff field. You can mix a few small impactors into the cloud of chaff just to make sure they can not afford to ignore it. This will in effect cause the shield's capacitors to drain over time limiting its ability to resist a full strength attack from your High Energy Laser weapons.
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**Fluids are *not* usable in space**
The Zhan method won't work. Any fluid, like most acids, will immediately evaporate when it is released from your ship. You'd have to pack the fluid in a projectile and penetrate the hull, to create havoc inside.
**Atomic oxygen is to be considered.. it is rare in space, but highly corrosive**
The absence of molecular oxygen will rule out a lot of corrosive agents. However, spacecraft are vulnerable for *atomic* oxygen in space. Normally there isn't much of it, but when present, it will even corrode polymers and carbon fiber. If you devise a weapon based on atomic oxygen, investigate what protective coatings are used by the enemy. A gold or platinum coating will protect a ship against it.
<https://en.wikipedia.org/wiki/Corrosion_in_space>
**To prepare a laser target, you could also use black adhesive particles**
One of the purposes of using corrosive weapons is weakening the target for a laser attack. In space, a corrosive weapon is far more difficult. If you'd like to prepare for a laser attack, consider projectiles containing carbon powder (graphite) with some adhesive. It will provide you with a black, non-reflecting laser target.
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What you want is a space equivalent of [Greek Fire](https://en.wikipedia.org/wiki/Greek_fire).
As others have stated, it can't be a liquid, but an adhesive gel that is sprayed or projected by a missile or sticks on contact may work.
As for oxygen that may be required, that others have mentioned, the gel can contain cells/beads of oxygen whose walls dissolve in the gel. So the gel would be effect for a given time period. The oxygen beads can be inserted into the gel at the last moment possible if required.
[Answer]
## Kinetic Energy
Along with all the other problems you have the issue of kinetic energy. Unless the two objects are traveling on more or less parallel courses at similar velocities the *relative* differences in velocity are going to be quite large.
For example two space craft in orbit above the Earth in the same or very similar orbits will have similar orbital velocities. In fact their relative velocities are so similar that with minor adjustments the two craft can reach zero relative velocities and perform a docking mission. (As you know this is more or less a routine operation today).
**The problem** in virtually any other situation but the one I just mentioned however the relative velocities of two objects traveling through space (compared to each other) will be almost always be so high that even minor impacts can be devastating e.g. witness the way the ISS has procedures for adjusting its orbit to avoid pieces of orbiting debris that are thousands of times less massive that it is.
So in any type of 'normal' space battle the combatants are going to have huge relative velocities as will anything they fire at one another. This makes anything they do fire incredibly dangerous. In the case of your chemical missile *its the missile itself* that's the threat not the payload. If you fire say a 200 kilo missile with a 10 kilo load of corrosive chemical and it hits the target at say 20 kps the amount of energy released by the impact will be orders of magnitudes more damaging than any chemical corrosion & also, unlike the corrosion effectively instantaneous.
And if the enemy intercepts the missile the fragments are potentially more of a problem than the original missile (think being hit point blank by shotgun pellets vs a rifle bullet - not really a lot to choose between them in terms of fates is there?
Finally all this is before you even consider how a chemical weapon would operate in a zero atmosphere, zero g environment. Under normal circumstances its entirely likely the vast majority of the payload would disburse into space without striking the target.
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**Maybe enough to scratch the paint**
Even if the corrosive material worked in a vacuum in any way it would spread out as soon as it is not contained. The forward momentum would not be enough to contain the expansion towards the vacuum. Eventually only a thin widespread cloud would attack the target, not even enough to damage the sensors. Probably for the sensors a sticky material would be more effective.
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If 'corrosive weapons' includes the possibility of delivery by nanites, there might be something to this concept.
Electrostatically charged nanites, that would stick to the hull. They would both release the corrosive fluid, AND chew away at the hull. A gazillion of them, all operating under a primitive collective hive mind AI, all concentrated on a particular spot on the hull, could do some serious damage. Think of iron fillings around a magnet.
If the corrosive substance inside these nanites is, perhaps, Chlorine Trifluoride as Chris H proposes, and these nanites deliver it to a specific spot before rupturing the containment vessel holding it, I can foresee one very big-badda-bang. That 'titanium' thing (["...but molybdenum, tungsten, and titanium form volatile fluorides and are consequently unsuitable."](https://en.wikipedia.org/wiki/Chlorine_trifluoride))is really interesting, since spaceship hulls could be envisioned to be made of titanium.
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Corrosion is a problem that NASA has been wrestling with since they started putting things in space. While they are not dealing with weaponized corrosion, they do have problems with off-gassing from things that are normally "just fine" in an atmosphere (some integrated circuits can rupture because they contain just enough gas to be a problem), to metals that will cause galvanic reactions. I was looking to work on a cube sat project and low earth orbit satellites also have to concern themselves with ionized oxygen.
[Answer]
**Nothing happens**
**Phase**: Chemical reaction will happen only if corrosive material is in liquid or gaseous phase. In space, liquid will evaporate instantly.
**Time**: Corrosion occurs when corrosive material remains on the target material for a sufficient time. In space corrosive material will be only in gaseous form which will not remain on the surface of the target because the target is moving with a high speed.
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**It would not work as proposed, because space is cold**.
Corrosive reactions are chemical processes, and the speed of such reactions is heavily dependent on temperature. See the Arrhenius law for example, which decribes many chemical processes accurately, and contains an exponential influence of temperature on the reaction speed.
The outside of a spaceship would presumably be pretty much space cold. Therefore, chemical reactions on the outside would be reaaaaally slow. Also note that all known corrosives are not as fast as usually depicted in fiction (but this can be handwaved with unobtainium). You can look up some videos of various substances dipped into different acids to get a feel for that.
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**Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers.
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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 2 years ago.
[Improve this question](/posts/221001/edit)
Remember Bob the Wizard from [this question?](https://worldbuilding.stackexchange.com/questions/215769/how-do-i-stop-annoyed-wizards-from-killing-people-all-the-time) Well, Joe's annoyed him one too many times. However, he can't kill him the normal way, so he's decided he's going to hire a demon to kill him.
Bob knows all about demons, though, and he *definitely* doesn't want to meet one face-to-face. He's decided to talk with this demon over the [magic-net](https://worldbuilding.stackexchange.com/questions/218785/what-would-a-website-look-like-in-a-magic-thought-based-internet). He still needs the demon to do some killing for him, but demons are Chaotic Evil creatures, and don't take kindly to bargains. Without meeting the demon face-to-face, he can't use a Binding spell to capture the demon, so **how can Bob the Wizard convince a demon to do the killing for him?**
Some clarifications:
* The demon is evil, and its goal is to cause as much pain and suffering for the world as possible. This aligns with Bob's goals.
* The demon doesn't care about materialistic or physical rewards, just causing suffering.
* The demon cares about self-preservation.
* Bob doesn't want the demon to kill anyone but Joe, and would prefer no collateral damage, although he can live with it.
* Bob cannot harm the demon physically or magically.
* Bob has no control over the demon except what he can muster through words & rewards.
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## Trap Joe with the Demon
When summoning a demon, it is common to summon them into some manner of binding circle. These circles do not harm the demons, but they do put a magical safety net between you and the demon. While in this circle, a wizard would typically interact with the demon to try to gain control over it, bargain with it, etc. Once the wizard has control or has struct a deal, he can release the demon from the circle and hopefully the demon will do what he wants. However, Bob does not want to actually have to meet the demon he is summoning because you can never actually be sure that you have successfully dominated a demon until you let it out, and since they are Chaotic (not lawful), you can not really trust them to honor any deal you strike.
Instead, Bob decides to skip the whole gaining control part of the spell. So he buys a few extra kilos of summoner's salt an proceeds to draw a large summoning circle around Joe's entire home while he sleeps... yes a summoning circle this big is more expensive, but totally worth it. He then summons the demon into the circle... and just walks away. The chaotic evil nature of the demon alone is enough that once the demon finds Joe trapped with it, all alone and defenseless, the demon will surely kill him of its own free will.
Since Bob wants to eliminate collateral damage, he can of course not keep the demon trapped there forever since the first good rain would damage the circle; so, when he comes back a few hours later, he simply banishes the demon from behind the safety of his circle, and everyone (except Joe) is able to just go about their lives.
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# Gather information about the psychological hang ups of the locals.
You need bargaining information to help the demon cause more pain. The more you have the better.
You should also research the demon, so you can tailor the information to them.
# Find an emergency to get everyone out of the village.
You need some reason that everyone could leave the village. You can use other spells or tricks to keep Joe in place. This will help minimize the damage.
# Find the demon and rant to them.
The demon doesn't like to bargain, but they do like to maximize suffering. Tell them about Joe and the neighbors and how to best hurt them, and offer them a chance to hurt them.
# Release the demon, and be ready to send monsters to disable them if they go far beyond the village.
Hopefully it works. What could go wrong?
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Look, if there's one thing Covid's taught us... everyone hates video meetings. They're awful, somehow more so than the regular sort, and anyone who says otherwise is playing Minecraft with the video turned off and their microphone muted.
Demons are no different. It might even be that they are tortured in Hell with constant video meetings. (Side note: design experiment to test whether I'm actually in Hell.)
So, he's just gotta meet face to face. Good salesman will tell you that they do most of their business with a handshake. I'm not suggesting the wizard do that literally, but for a bargain of this magnitude it has to happen. They have to meet physically. No self-respecting demon is going to give Bob the time of day unless he's willing to sit down at a table (or stand at a crossroads) and make his pitch. It may be technically true that the demon is the one selling the service here, but like any good tradesman, the demon has more than enough customers, while Bob only has the one demon who will sell him this service (a classic monopoly). This wizard has to cater to the demon, not the other way around.
If you were selling something that's in-demand, so much that you have no free time, are you going to go out of your way for someone who places a telephone order?
It wouldn't be bad if they got to know each other. To appreciate what they have in common, their desire for the utter despair of the Abyss. Their soul-deadening diabolical nature, their yearning to crush all hope. To see that this is much more than just a business deal, but almost a favor from one friend to another. This is how deals were done in an earlier time. This is the sort of deal Bob needs to strive to make. He needs to put on his best clothes, head over to the desolate crossroads at the witching hour, and to make sure that he has a pen inked with his own blood ready to go (if you have to ask the other guy for his, are you even serious about the Faustian contract?!). He needs to look straight ahead with shoulders tall and straight, not shuffle to the meeting with eyes downcast.
Any Wall Street hedge fund manager will tell you this is how deals with devils. There are like at least a dozen books on the shelves at Barnes and Noble that lay it out in better detail than I can. Though, I thought this site was supposed to be about fiction questions.
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Maybe not a direct answer to your question, but an alternative would be to
### Use an intermediary
There might be an agency, or some individuals, who are willing to perform this dangerous task, in return for a (rather high) fee. It's not unlike the real world; high-level criminals almost never send orders to contract killers directly (but that's mainly because they fear being exposed).
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Make a deal, demon are known for making deals. Offer him the soul of his first born and second born, and then never have kids. This way even if he doesn't like to deal he has incentive to keep him alive until he has children. Remember the demon wants to hurt and kill any ways. So he shouldnt be very demanding, since your essential paying him to do what he would normally do for free.
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Bob sends the following message to the demon:
"Greetings demon. Know that I, Joe the Good, defend [Joe's town] from evil with my trusty dagger, so stay away from our puppy orphanage. Signed, Joe."
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**Five Star Reviews**
How do you know an unknown seller will meet the terms of an agreement? Just look online for a list of anonymous reviews. The demon Hor'Glabrethor the Blood Gobbler has 4.7 out of 5 stars.
That means Bob is confident the demon will meet the bargain. That is provided of course Bob offers a fitting sacrifice.
For a job like this, the standard sacrifice is the life of a child or loved one. Demons like these sorts of things because they cause suffering to the sacrificer. Sometimes they are happy for you to sacrifice your reputation or maybe just a limb or an eyeball.
The demon wants to keep the bargain because they get:
(a) The initial suffering of the sacrifice.
(b) The suffering to the victim and their family.
(c) Several more generations of suffering when Joe's family discover who done it, and the resulting murder feud between the two families.
(d) Positive reviews, which means most bargains in the future.
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This question is akin to [Benefits of Boomerang Enchantment on Items](https://worldbuilding.stackexchange.com/questions/196505/benefits-of-boomerang-enchantment-on-items) and covers the Rubberizing Enchantment.
When an item kills a Plop, a slime-type monster that looks like a glob of sludge with a big, toothy mouth and four flail-like stalks atop its head, that item is promptly altered by the Plop's released magic. This alteration is the Rubberization enchantment, and it is kind of sucky.
When something is Rubberized, it becomes tough but flexible. Take your typical rock; solid and unbending right? Once Rubberized, it'll be firm but springy, sort of like a tennis ball, and it'll bounce. An iron ingot would bend, flex, and deform akin to a pool noodle. Basically, rigidity is decreased while tensile strength is increased. The harder the item was, the more flexible it'll become after being Rubberized.
My problem is that this is (most likely) *useless* for anything an adventurer would use it for. Rubberized Armor would likely fit better, but it'll also *yield* when struck, so it's too flexible to be feasible (Ex: silk is yielding, so yielding that when a blade hits it it will conform to the blade and cut you!). Rubberized weapons would have low rigidity, so swords and spears (any cutting weapon really) would fail.
Bludgeoning weapons *could* still work, but since they have decreased hardness (meaning rigidity) I'm not sure how effective they'll be. So my question is: **What Weapons Would Benefit From the Rubberizing Enchantment?**
Clarification:
1. By weapon, I mean an item that can kill a Plop. Plops are essentially video game slimes, so the closest IRL analog is slugs. So the item in question has to be capable of: crushing (crushing a Plop is difficult, they'd just slip out from a dropped anvil like a pea from a pod), frying, incinerating, dissolving, dehydrating, smothering, slicing, or pulping a Plop.
2. Flexible items gain greater flexibility (or tensile strength) upon being Rubberized. Hard items gain tensile strength proportional to their former rigidity and vice versa; a rock will be more flexible than a rubber band after being Rubberized.
3. Only organic or steel items (because steel contains carbon, which is generally organic in origin) can be Rubberized. There has to be proximity for the item to be enchanted; a coat wrapped around a club, if used to splat a Plop, would be Rubberized along with the club, but if one shot a Plop, only the arrow would be Rubberized.
4. The tech level is medieval, specifically between European technology between the fall of the Western Roman Empire and the Renaissance. Plops are like rats; they exist out in nature, but their numbers are much higher in villages, towns, and cities (lack of sanitation+higher populations=high amounts of edible refuse).
Criteria for Best Answer (same as in linked question):
1. The best answer will start with a basic summary of how useful this Enchantment would be on items in general, specifically items that can be used to kill the slimy, rubbery slug-like glob of malevolence that is a Plop.
2. The best answer will cover where this enchantment would be most beneficial; ie. which items would be best benefited by this enchantment. By items, I mean weapons, armor, valuables, and perhaps miscellaneous objects (things you'd find around the house).
3. The best answer will cover #1 and #2 thoroughly.
You have my thanks for your input and feedback, I really do appreciate it! If you choose to VTC or down-vote, please give me an explanation so I can fix this question and better contribute to this site in the future.
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### You're forgetting the waterproofing qualities of rubber
Your in a medieval setting, you don't have great waterproofing tech. Silicon beads are centuries away. Roofs leak, shoes are soggy after a day working in the mud, water storage is difficult as everything leaks, water transportation is difficult as everything leaks.
* Step on two slugs, one under each shoe, and now your shoes are gloriously rubberised and repel the water. Your no longer going to get trench foot in the field.
* Build a tank out of steel. Smush a slug with it, and then put that rubber tank inside a slightly larger steel tank. Now you have a lined rubber tank that will not leak or contaminate your water. You can now transport water by horse and cart, allowing people to live further away from water sources.
[Answer]
**Unless your goal is to make rubber-band guns...**
This is a great natural defense. No one would use their best sword or favorite spear to kill a plop (once this consequence was known). What would be the point? This defense always reduces a superior weapon to an inferior weapon. Rubber swords are probably useless even for training as their length would lead to quick degradation of the rubber (aka, they break). So, unless you think rubber-band guns are valuable, there is no weapon I can think of that would be a practical or beneficial result of wasting a perfectly good and most likely better weapon to get it.
**But... you just invented the Rubber Plop Plantation Cottage Industry!**
On the other hand, there's lots of useful things that can be done *with* rubber. You can make tires, coat the handles of tools, create safety barricades... The list goes on. So what you really have is the source of rubber that doesn't require rubber plants.
But you *could* use the idea of the [banana republics](https://en.wikipedia.org/wiki/Banana_republic) in your story. Whole cities focused on the domestication and death of plops for the sole purpose of producing rubber. What kind of rubber you need would dictate the type of material used to kill the plop. All of this is run, of course, by a power-hungry corporate boss because the secret of rubber production is a Guild Privilege.
**Nevertheless, the simple answer to your question is... *none.***
Even if the enchantment only *coated* the object with rubber (rather than completely converting it to rubber, which is how I read your question), there's very little practical value to the enchantment from the perspective of "what could an adventurer do with the rubberized object to forward the adventure?" I could see the value of rubberized armor... but if you have to *kill* the plot with the armor to get it coated with rubber... it gives a whole new meaning to the phrase "belly flop."
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You've got to review your notions about armor. Being rigid isn't the only thing that makes armor good. Also, have you ever actually used one of those blue and red erasers? That stuff is hard to cut and if you could make a half-inch thick suit of that stuff you'd have quite the protection against stabbing!
And to this day, rubber is used for gloves and boots to make them resistant to some kinds of damage. Latex items are generally more resistant to abrasion and friction as well. So you can enchant leather or metal gloves and boots, they will keep most of the properties they have while being easier to put on and more comfortable.
Also, rubberize a staff and it becomes a whip. That is a very vicious kind of weapon, which is a hassle to parry. It also adds both insult and injury to already existing insult and injury should it hit bare flesh.
In fact [there was a weapon like that in ancient India. It is called *urumi*](https://en.wikipedia.org/wiki/Urumi) and this is what you would get if you enchanted a longsword with rubberizing. In some forms they also put multiple blades in the same hilt.
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## Why kill something so valuable?
I'm afraid that with the qualities you described, the Plops are soon to become a strategic resource that must be gathered and stored instead of senselessly killing them:
### The other way around - weaponizing the Plops.
Getting through a fortifications is a hassle. As well as going through the armor of a knight. Plops provide a nice solution to this issue, since the enchantment affects everything in proximity of the deceased Plop:
**Walls:**
1. Take a ballista bolt and a small-size Plop.
2. Put the Plop into a container
3. Affix the container to the ballista bolt's tip.
4. Hit the wall near it's base. The bolt will crush the Plop against the wall. The Plop will then rubberify both the bolt(which would shatter anyway) and a section of the wall.
5. Repeat until enough of the wall is rubbery
6. Watch in amusement as the pliable rubber fails to support the weight of the wall which then crumbles.
**If the wall is too thick:**
1. Take as big of a Plop as you can find that you can still load into a trebuchet.
2. Insert a stone into the Plop. It will likely take a while to digest.
3. Launch the Plop against the wall The stone inside will do for a nice *plop* against the wall. The radius of rubberification should be sufficient for most purposes.
4. Profit.
**Armored knights:**
Arrows have a notoriously hard time of going through the [armor of a knight](https://www.youtube.com/watch?v=DBxdTkddHaE). They have even hard time going through layered enough cloth. To remedy the cloth-issues, the tips of the arrows were sometimes [waxed](https://www.youtube.com/watch?v=oC30A6noRmY).
What if we could instead of maybe hitting an enemy into a weak spot use our archers to remove the armors of the enemy? The idea is same as above, only the size of the Plop would me much smaller this time. Since the tip of the arrow would get rubberized as well, the arrow itself wouldn't do much. However the armor with rubberized, pliable spots would suddenly be less useful - which would spell trouble since you rarely shoot just one volley during a battle.
Or if you had a good enough construction techniques, you could do a segmented arrow with two tips. First would serve to "apply" the Plop, while the second would use the rest of the kinetic energy to proceed through the rubberized spot. I'm not sure if this would be too feasible.
### Reactive armor - letting others do the killing, while making a killing.:
Why kill the Plops when they can be so usefull?
* Coat your armor in Plops. Affixing these might be little tricky, however some kind of pocket like system could work.
* When someone tries to hit you with something sharp, he will pop one(or more) of the Plops.
* Congratulations, not only you survived, you also disarmed your opponent.
Note, that since the Plops would be depleted, you also want to wear something underneath - at least a gambeson with a layer of rubber on top. Considering that enemy will lose his weapon, this should be quite ok for small fights. Might be a little tricky for the battlefield though.
The iron/steel armor is rather expensive. So much, that only the wealthy could afford that. And you are telling me, that using a vest with **pockets** has a similar impact on your safety?
### P.S.:
As a side note - you mentioned that they can rubberify anything organic. Strictly speaking, a person is also made of organic matter. However I think that rubberifying a human is, well, inhuman so I've decided to skip a whole lot of interesting anti-personnel Plop applications.
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**Modern Vulcanised Rubber Boots.**
Design a boot with a 2 inch thick wooden sole. Use it to stamp a plop to death. The wood turns into vulcanised rubber, and you carve out "teeth" like a modern military boot.
Bam! Footware that is waterproof, hard-wearing, needs little maintenance, does not rot, and is **all-terrain**. The most important piece of kit in a medieval adventurer's arsenal.
For comparison medieval leather flat soles are garbage on muddy terrain. It is easy to fall over, especially in the heat of a swordfight. This can be fixed by adding hobnails, but this makes the boots garbage on hard terrain such as flagstones. Again it's easy to slip and fall over.
The rubber boot sole has none of these problems -- you are not at constant risk of falling over if you need to run from one surface onto the other, for example in the middle of a fight.
Another advantage is you don't need to clean your muddly boots between adventures. Leave a pair of leather boots covered in mud and they will soon rot away. Not true for rubber soles at all.
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I can think of several weapons that would be improved by replacing *parts* with rubber.
## Nets
A gladiator's net is a weighted net that, while primarily designed for entanglement, is capable of inflicting damage when the weights themselves are used as a flail. Some gladiator nets used light chain for extra strength, either in whole or as a part of the net itself.
With the transformation types you're talking about a net made of light chain with heavy weights would become more flexible and still difficult to cut. Cutting one of the now rubberized links wouldn't cause the entire thing to unravel. The additional flexibility of the material would serve to increase the entanglement effects, and being stretchy means that a brute force attempt to break the net would be less effective as the material would tend to spread the load differently.
The weights themselves would become less deadly, but this simply opens up some new options like bounce-casting. Or you can just replace the weights with new metal or stone weights and get the original flail impact back.
## Whips
This will depend on the actual properties of the material but in general more flexible is better, as long as the business end can stand up to the forces involved. After conversion you take the thong of the whip and build a new whip around it. Experimenting with various materials might produce a good rubberized substance for the fall as well.
## Flails
Thus one should be obvious. Take a flail, ruberize it, then replace the heads with original metal. Maybe take the original heads off the flail and replace them with bits of wood before you rubberize it, then put the original ones back. The rubber handle is flexible but grips well and reduces transmitted impact shock.
## Seige Weapons
Take a bunch of wooden staves and rubberize them. Now put them in place of the rope in a catapult's torsion mechanism. Use big chunks of softer material to add shock absorbers on your crossbar, reducing the damage the catapult does to itself when fired.
If you can find the right material you could create a new type of siege weapon based on the shanghai, or sling shot - long, elastic 'ropes' from the frame to the cup, tensioned and then released.
## ...and many more
Pretty much any melee weapon will benefit from the vastly improved grip of a rubber-coated handle. Make weapons out of metal tubing, rubberize with plops, then cut the tubing down and stretch over your sword hilt. Wrap bits of rubber around your bow grip. Add softer rubber sheathing on big-impact weapons to act as shock absorbers.
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DISCLAIMER: No, this is not a duplicate of [this question](https://worldbuilding.stackexchange.com/questions/34036/surviving-re-entry-in-only-a-space-suit). We are talking about reentering Venus' atmosphere as opposed to Earth, and the suit parameters are rather different to a current suit.
Background:
A terrorist has detonated a bomb on the main character's ship, in low equatorial orbit ~200 km above Venus. They are on a hull inspection EVA at the time, and to escape the blast hide behind one of the many auxiliary craft on the ship, a biological sample pod designed to evaluate habitability of Venus' atmosphere. Unfortunately, the explosion triggers the automatic debris avoidance program and activates the pod's engine in such a way that the character and biopod are now on an atmospheric entry trajectory.
The suit is made with carbon nanotube fabric in most places, except where impossible. There, they use standard MMU-like materials. The suit has a delta-v comparable to [SAFER](https://en.wikipedia.org/wiki/Simplified_Aid_For_EVA_Rescue), an oxygen reserve of 8 hours and a parachute to be used in emergency deorbit situations. Mass is 70 kilograms.
The biopod is not designed to survive surface conditions on Venus, its purpose being to float in the atmosphere at an altitude of 30-50 km to test survivability of microorganisms in this environment.
Can they survive this situation(i.e land on Venus or return to ship successfully, with survivability for the nominal EVA duration)? If not, what is needed to allow it?
I appreciate your feedback. Thank you!
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No, you would burn up in the atmosphere of Venus. The Safer unit can supply an orbital delta V of perhaps 3 m/s, whilst orbital speed around Venus will be very roughly 8000 m/s so it won't make any difference. The parachute would not work at orbital speeds, it would be shredded and burnt. Even with sufficient braking the atmosphere is so dense and hot that you would die long before reaching the ground.
Further to editing of the original question:
Plan B suggestion - use a heat shield to shed most of the orbital speed then jettison it and use a ballute inflated with oxygen/nitrogen to slow further still. Very tricky but if you do it right and use a few atm pressure to inflate the ballute you could end up floating in the atmosphere of Venus high up where the temperature is around 20 degrees C. Then climb into the ballute and await rescue. Not good but much better than trying to land.
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**Get in the biopod**
The biopod is activated and it is going thru its programmed routine. The biopod does not land on the surface. The biopod does not burn up in the atmosphere. It descends from orbit to float at described height, gathers samples and then returns.
Your character might burn up on the outside of the biopod as it sheds velocity and descends to its sample gathering height. If he can get in there he will be protected. It is biopod as escape pod.
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I had this idea for my sci-fi book, there's not going to be a **central** galactic government, very contested little time, but I do wanna pursue this.
The more shadowy inhabitants of the center of our galaxy are not from here. They have traveled through dimensional doorways opened by the extreme forces around the supermassive black holes at galactic centers, located within the holes themselves. I'm not sure precisely where they're from, or if they even know, but their capital, here, is centered around Sagittarius A.
I'm just not sure on the laws of physics, the current idea I have is a metal planet like sphere separated under habitable domes to counter incoming radiation, while the inner layers filled with secrets and experiments.
My question is what would be the most efficient way to draw power from a black hole's excess, should it even be a city or just a scattered array of stations and panels?
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A black hole, if it has an accretion disk, will cause said disk to radiate X rays, due to the dissipation of the momentum carried by the matter falling in it.
Just harvest those X rays and convert them to usable energy, more or less like we do with our solar panels.
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**One wave of the hands.**
Your people traveled through dimensional doorways that you invented for the story. Since the transdimensional
doorways
are already invented (and no-one can complain about their physics!)
, use those. Stuff from that original dimension continues to stream through them in energetic, coruscating streams. It is not great for our dimension that all this weird stuff comes busting in and getting mixed up with the native stuff and in fact discovery of that stuff might be the first clue for our dimension that something is up.
Your invader people are made of weird stuff like that, and they make use of the streams using
devices like great waterwheels or wind turbines, being turned by the difference in dimensional energies and the creepy stuff that those
energies are propelling into our dimension.
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[**The Penrose Process**](https://en.wikipedia.org/wiki/Penrose_process)
This is a way to extract energy from a spinning black hole. It is similar to the classic sci-fi trope where you slingshot a spacecraft around a rotating body. In both cases you launch something near a heavy rotating body so that what emerges afterwards has greater energy that what went in, and the body is rotating slightly slower.
You carefully line up two asteroids and drop them into the black hole. One is swallowed up and the second comes flying out with greater energy than before. Then you somehow catch that asteroid and harvest the kinetic energy. There is no need to build a superstructure around the black hole.
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Kurzgesagt has a nice [video](https://youtu.be/ulCdoCfw-bY) about black holes in which they introduce 2 methods to harvest energy from a black hole. One is the Penrose process as mentioned in a [previous answer](https://worldbuilding.stackexchange.com/a/176805/56150) (you drop a thing into the black hole while going around it for a boost) and the other is building a mirror array around the hole and shooting EM waves through a hole in the array (the surviving waves would accelerate and can be caught in another hole in the array).
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Sagittarius A is orbited by a number of stars. [Here is the current list](https://en.wikipedia.org/wiki/Sagittarius_A*#Orbiting_stars). Most of them are way more massive than the Sun, and thus give off more energy.
You could harvest a lot of energy from the star system with regular solar panels, or multiple Dyson spheres. You can then beam the energy to the base planet.
Removing energy from the black hole directly would reduce its mass and thus change the planet's orbit.
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To maximize the energy output of a black hole, you want it to be relatively small as the smaller it is the more hawking radiation it outputs. But you also have to keep feeding it matter so it doesn't completely evaporate.
I suggest you look into the idea of Kugelblitz drives for starships, as you you'll likely find answers to a lot of the questions you have about using black holes for power.
<https://en.wikipedia.org/wiki/Black_hole_starship>
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you could create matter out of nothing near a black hole, you just need to wait till spontaneous creation of a particle/antiparticle pair and for one of them to be sucked into the black hole. Boom you have a free particle. multiply times gazillion, profit!
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Someone in the comment section of [my previous question](https://worldbuilding.stackexchange.com/q/162881/32097) pointed out the energetic problem of [ectotherms](https://en.wikipedia.org/wiki/Ectotherm) with human intelligence (the brain needs a lot of energy). I still want to keep my lizardfolk restricted to warmer climates, as all the other suggestions just didn't work (lizardfolk don't have blood feuds, they aren't toads, and they have a more "human" respiratory system; all of that leaves Clint's Reptiles' endless list of things that Asian water monitors need and the kinds of diseases they can get as the best reason of them remaining in the background).
I thought maybe an in-between of ectothermic and endothermic temperature regulation would be a good way to have the cake and eat it (one half-gone, one remaining, balanced, as all things should be).
**The question is if such in-between is possible and if yes, how could it work?**
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The term you may be looking for is "mesothermic". Mesothermic creatures maintain a body temperature above their environment, but it's not a stable temperature. There have been many animals that are, or were mesothermic. Sharks, Tuna, Leatherback Sea Turtles, and echidnas are all mesothermic. It's believed many dinosaurs were mesothermic.
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**Regional endothermy.**
You want your cold blooded "lizardfolk"\* to have cold blooded heritage but to be active predators like badgers and be smart like humans. You could allow them to use muscular action to heat blood and then shunt it where it was needed. Several lineages of fish do this and some moths also.
<http://bioweb.ie/warm-blood-sharks-tunas-superspeed/>
[](https://i.stack.imgur.com/AjcBc.jpg)
[Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0185185)
>
> Regional endothermy is the ability of some fish lineages to maintain
> certain body areas at higher temperatures than the surrounding water
> by means of vascular countercurrent heat exchangers or specialized
> thermogenic organs. This adaptation involves an active mode of life
> and much higher metabolic rates than those of the ectothermic fishes
> of the same size... Here it is proposed that regional endothermy was
> present in otodontids and some close related taxa (cretoxyrhinids),
> playing a key role in their evolutionary history, allowing gigantism
> and the maintenance of active macropredatory modes of life.
>
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>
In lazy mode they would bask, hang around, not doing much. But when there was something that required action comparable to an endotherm they could make it happen. They would generate heat using muscles and shunt the hot blood to the organ system needed. If it were for thinking then the brain. If for hunting / fighting then the muscles. If digestion needed to speed along then the guts.
Possibly they could do two things at once but for the story it would be interesting if they could not: thinking and fighting in the cold are mutually exclusive. When they get a chance they do their thinking first.
The possibility of this adaptation leading to gigantism also offers interesting narrative possibilities. I suspect that the largest saurian active predators must have had something like this. Monitor lizard get big too. Could Komodo dragons have adaptations allowing them regional endothermy? Yes!
[Genome of the Komodo dragon reveals adaptations in the cardiovascular and chemosensory systems of monitor lizards](https://www.nature.com/articles/s41559-019-0945-8)
\*Re toad lineage: If your folk self-identify as Varanidae then it is rude of me to keep referring to them as toads. Lizardfolk too need to live their own truths and I apologize. But for purposes of understanding biology, sometimes genus-of-origin information can be helpful.
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You’re asking the wrong question. What you want is a halfway house between homeothermic and poikilothermic, not between endothermic and ectothermic, and there are lots of examples. Endothermy is only one of three known mechanisms for homeotherms to regulate their temperature. In fact desert lizards are a good example, keeping their body temperature almost constant during the day using only environmental factors rather than body heat. See the [Wikipedia article](https://en.wikipedia.org/wiki/Homeothermy) on homeothermy.
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Everyone has made really great suggestions.
I think the stumbling block for your lizardfolk is for them to have human-level intelligence given their metabolic energy budget.
Lizards have brains now that provide them with the capacity to hunt, flee, seek shelter and reproduce. So it seems they only need a different form of brain cell for higher brain functions like cognition and deep memory.
So maybe they have mesothermic cerebral cortex. This structure -- it might be paired with a symbiote -- accumulates enough energy then mentation occurs until it depletes its reserves. Wherein the state of their mind remains constant -- like an abacus when no one changes it -- until they accumulate enough energy again. Then they start mentation again.
When they are enervated, the regular old lizard brain they have now is still active and keeping them alive.
The experience would be similar to being a narcoleptic when they run out of energy their conscious minds stop and resume later, they would have to accommodate changes in time, situation and location.
The chemical processes of their high brain functions would be very different, and I couldn't begin to describe a plausible mechanism for this to work.
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You only need homeostasis for the brain. You could give your lizards a symbiotic infection for a separate carapace creature that regulates body temperature of the brain region. The lizard can not regulate the temperature for the rest of its body.
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before I get into my question I wanted to thank everyone for their input in my first thread about the general principles of river drawing. I have taken your comments under consideration and began redrawing my waterways accordingly. In the meantime, I'd like to ask a question about rivers and their relationship to mountains.
I've been working on a small, narrow gauge logging railway in a mountaineous region of my land, that runs, for the most part, in a picturesque river valley. Here is something that I've been workshopping and I've been wondering if it is at all prototypical - can a river that was in a relatively flatter part of the land later run between two (or more) large peaks?
I know the reverse can happen, where two imposing peaks on either side can give way to flatter land, but I'm wondering whether what's on my map is at all true to life, given that most major river basins, from what I've seen, tend to get flatter the closer they are to their mouths. Are there any mitigating factors that could make something like this happen in real life?
The use that I would have for an opening like this would be to run the railway through it alongside the river. The trouble is that I haven't seen many examples of something like this in real life except for the confluence of the Hron and Slatina rivers in Slovakia - the Hron ran in a relatively wide valley north of Zvolen, and then squeezes in between two peaks when it meets the Slatina in Zvolen. Because this happens in an industrialized part of the city (Zvolen), I have no idea whether this course was in any way affected by man made activity.
Of course, if I had to implement a ridge bridging these two mountains together, I could run the railway through a tunnel, but that would be an expensive engineering venture for a frugally built logging railway, and they probably wouldn't have bothered. I do have some alternative routes, but I'd like to get some clarification before fully committing to anything. Thank you!
EDITED: This was exactly what I was looking for! Thank you so much to everybody who responded! You guys rock :)
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This is actually fairly common. There is even a [website dedicated to them](http://www.durangobill.com/AncestralRivers/AncestralRiversIndex.html).
Often this is a sign that the river is older than the mountain. They are often called **ancestral rivers and gaps** (such as the water gap and wind gap in the US). the river keeps cutting as the mountain rises (or the rest of the land erodes away) cutting a valley in it. The river does not even have to be older it just has to find a crack, or porous section to cut through. The trellis type of river drainage is known for having lots of such cross cuts.
Also keep in mind flat areas may not have always been flat, glacier dams can redirect water AND carve flat land at the same time sometimes even push up smaller mountains and hills (moraine) from dropped debris which then get cut though.
These are uncommon enough to be noticable but common enough they will not draw much attention.
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## The Danube does it twice
It is not at all uncommon for a river to flow slowly trough flat land only to find itself constrained into a narrow gorge.
In European geography, probably the best known example is the [Danube](https://en.wikipedia.org/wiki/Danube), which crosses the Carpathian mountains twice, first through the [Devín Gate](https://en.wikipedia.org/wiki/Dev%C3%ADn_Gate) at the northen end of the range,on the border of Slovakia and Austria, and then through the spectacular [Iron Gates](https://en.wikipedia.org/wiki/Iron_Gates) at the southern end of the range, on the border between Romania and Serbia.
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> * Devín Gate or Hainburger Gate (Slovak: Devínska brána; German: Hainburger Pforte) is a natural gate in the Danube valley at the border of Slovakia and Austria. It is one out of four geomorphological areas of the Devín Carpathians, part of the Little Carpathians mountain range. Passau, Devín Gate, and the Iron Gates divide the Danube river into four distinct sections. ([Wikipedia](https://en.wikipedia.org/wiki/Devin_Gate))
> * The Iron Gates (Romanian: Porțile de Fier, Serbian: Ђердапска клисура / Đerdapska klisura or Гвоздена врата / Gvozdena vrata, Bulgarian: Железни врата, German: Eisernes Tor, Hungarian: Vaskapu) is a gorge on the river Danube. It forms part of the boundary between Serbia (to the south) and Romania (north). In the broad sense it encompasses a route of 134 km (83 mi); in the narrow sense it only encompasses the last barrier on this route, just beyond the Romanian city of Orșova, that contains two hydroelectric dams, with two power stations, Iron Gate I Hydroelectric Power Station and Iron Gate II Hydroelectric Power Station. ([Wikipedia](https://en.wikipedia.org/wiki/Iron_Gates))
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>
[](https://i.stack.imgur.com/FUVQu.png)
*The middle and lower course of the Danube, with the Devín Gate and Iron Gates marked with red circles. Own work, derived from a [map of Europe](https://commons.wikimedia.org/wiki/File:Europe_laea_topography.svg) by [Dbachmann](https://commons.wikimedia.org/wiki/User:Dbachmann) available on Wikimedia under the CC BY-SA 4.0 International license.*
On the same map you can see the [Olt river](https://en.wikipedia.org/wiki/Olt_River) flowing east to west through southen Transylvania, only to make a sharp turn to the south and cross the Southen Carpatians through a narrow gorge, the [Olt Defile](https://en.wikipedia.org/wiki/Olt_Defile).
## The Yarlung Zangbo / Brahmaputra
But the most spectacular example worldwide is, in my opinion, the Yarlung / Brahmaputra. Both the upper course (the [Yarlung Zangbo](https://en.wikipedia.org/wiki/Yarlung_Tsangpo), flowing west to east through Tibet), and the lower course (the [Brahmaputra](https://en.wikipedia.org/wiki/Brahmaputra_River), flowing east to west through Assam) were known since times immemorial; but it was only in the second half of the 19th century that the awe-inspiring canyon connecting them was explored and the two rivers were shown to be one and the same. The [Yarlung Tsangpo Grand Canyon](https://en.wikipedia.org/wiki/Yarlung_Tsangpo_Grand_Canyon) is 504.6 km (314 miles) long, with a drop of 2,300 meters (from 2,900 to 600 meters altitude); it is the deepest canyon in the world, with an average depth of 2,268 m (7,440 feet) and a maximum depth of 6,009 m (19,714 feet). Or at least it is so written in the Wikipedia.
[](https://commons.wikimedia.org/wiki/File:Ganges-Brahmaputra-Meghna_basins.jpg)
*Course of the Yarlung Zangbo / Brahmaputra. Map by [Pfly](https://commons.wikimedia.org/wiki/User:Pfly), available on Wikimedia under the CC BY-SA 3.0 license.*
>
> *I have to attempt a curious and important journey, the plan of which has been drawn up by my learned friend and colleague, M. Vivien de Saint Martin. I am to pursue the track of the Schlaginweit Brothers; and Colonels Waugh and Webb, and Hodgson; and Huc and Gabet, the missionaries; and Moorecroft and M. Jules Remy, and so many celebrated travelers. I mean to try and succeed where Krick, the missionary so unfortunately failed in 1846; in a word, I want to follow the course of the river Yarou-Dzangbo-Tchou, which waters Thibet for a distance of 1500 kilometres, flowing along the northern base of the Himalayas, and to find out at last whether this river does not join itself to the Brahmapoutre in the northeast of As-sam. The gold medal, my Lord, is promised to the traveler who will succeed in ascertaining a fact which is one of the greatest Desiderata to the geography of India.* (Jacques Eliacin François Marie Paganel, Secretary of the Geographical Society of Paris, Corresponding Member of the Societies of Berlin, Bombay, Darmstadt, Leipsic, London, St. Petersburg, Vienna, and New York, and Honorary Member of the Royal Geographical and Ethnographical Institute of the East Indies, explaining his original travel plans to Lord Edward Glenarvan of Scotland, in Jules Verne's [*In Search of the Castaways*](https://en.wikipedia.org/wiki/In_Search_of_the_Castaways), 1867).
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The Colorado river at [Cameron AZ](https://www.google.co.uk/maps/@35.8778241,-111.4112493,3a,75y,138.05h,86.59t/data=!3m6!1e1!3m4!1smG5ZvKupENJY1px9VsR7BQ!2e0!7i13312!8i6656) flows across a fairly flat landscape.
Go downstream, and you enter the [Grand Canyon](https://www.google.co.uk/maps/@36.2072632,-111.8039071,3a,60y,89.43h,106.22t/data=!3m6!1e1!3m4!1svg7yQNgFpsVG5r1Nrt-U6w!2e0!7i13312!8i6656). This has been caused by a mountain forming event and the river cutting down through the mountains as they rose (over geological timescales)
Following the Colorado downstream you can see several times when it moves from plains to gorge and back again.
So it can happen, it needs a river that is unusually determined to follow its course, even as mountains form across its path.
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Another, and much smaller scale, example is the Derwent River in the English Lake District. It meanders northward through the flat land of Borrowdale, before entering the narrow Jaws of Borrowdale between Castle Crag and Grange Fell. [Link to Google Map of the area](https://goo.gl/maps/c5Bh1bC6ZZ72)
In this Google Earth view you can see the river and the road between fields in the broader flat part of the valley, and where they are forced to run close together through the Jaws of Borrowdale.
[](https://i.stack.imgur.com/kETf0.jpg)
There are two aerial photos looking south / upstream at <https://www.visitcumbria.com/kes/borrowdale/>
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**Closed**. This question is [opinion-based](/help/closed-questions). It is not currently accepting answers.
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**Want to improve this question?** Update the question so it can be answered with facts and citations by [editing this post](/posts/96803/edit).
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I would like for a species to be more intelligent than humans, i.e. be able to solve logic puzzles quicker, make mental math calculations easier, and remember more information. But I do not want them to be so intelligent, they are bothered by the slower-thinking humans, or are just slightly annoyed about this.
Other than general improvement to their intelligence, their psychology remains the same as humans. The aliens and humans have fully merged their societies over the course of one hundred years, so they interact in just about every setting.
The average human IQ is 90 to 110, and I was guessing perhaps the average alien intelligence would be near 130-150. Does this make sense?
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In any society, there are a range of personalities. It's likely that *some* members of your alien species would be irritated by humans - in the same way that *some* humans of average intelligence are irritated by humans with IQ in to 80's. But *many* (probably *most*) humans hardly even notice if they're talking to someone of lower IQ, and if they do most are forgiving of that. So if your aliens really do have the same psychology as humans, just with increased intelligence, then most of them should be basically fine with humans.
Also, consider the subject matter of conversations. A world-class mathematician probably won't be irritated by talking to a person of average intelligence about football - but talking to even an intelligent layman about mathematics might be extremely frustrating. It's possible that many of your aliens will find human company perfectly enjoyable, as long as the conversation stays away from technical or academic topics.
Assuming your society is vaguely capitalistic, you'd probably find that intelligence-based jobs - for example, research science positions - would tend to hire exclusively aliens, while professions for which intelligence isn't as critical would hire a mix; that means that humans and aliens wouldn't have much reason to talk science with each other, which would probably make everyone happier.
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Yes, but you honestly don't have to take my word for it. You can just ask humans with higher IQs if dumber people annoy them.
There's also no reason to assume that every alien will react the same way to someone with a lower IQ. If the aliens have a high EQ as well, there's no reason to assume that they'll slight humans for being dumb.
So just give your aliens above average empathy too and the problem you're worried about shouldn't develop.
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Because it is going to be a very long response here is a **short summary**:
While your society might eventually reach an equilibrium and function smoothly, there will be distinct alien and human subcultures. I also believe that if aliens have the same psychological traits and tendencies as humans, humans will be perceived as second-class citizens earlier than later. The only exception if humans somehow can compensate for the intelligence gap. Alternatively, the aliens must have a set of attitudes and preferences different from humans.
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# General Differences
The way you describe aliens, I assume they would be superior to humans at least in three areas:
* ability to see patterns and connect them;
* speed of mental processing of information;
* memory.
### Patterns
Higher intelligence improves an ability to see patterns and connecting them. (Patterns here mean any patterns from physical to mental.) While it may lead to better decisions and future predictions [it is not necessarily so](http://www.bbc.com/future/story/20150413-the-downsides-of-being-clever). Higher intelligence may also result in more biased decisions (because it is easier to justify those biases) and higher rates and success of manipulation others.
Despite the possible downsides, better pattern recognition, in general, gives an advantage in many areas of human life. Mostly, it is associated with better and faster learning.
### Processing speed
People with high intelligence think faster. Partially it is associated with a greater ability to find patterns.
Faster thinking allows to process more information and respond to critical situations in a more timely manner.
### Memory
Better memory is highly advantageous as it allows to retain more information, which leads to better pattern recognition and higher processing speed. Cross-referencing becomes much easier, as well as establishing not so obvious connections. The latter is very important for innovation and scientific research.
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Some of the previous responders are very optimistic and assume that these differences in general abilities will not affect communication with intellectually inferior species (humans). But I seriously doubt it.
Aliens will have to explain their thought process to humans much more frequently and in more detail. This can be annoying. Their ability to draw on a greater number of references and connect them faster might trigger inferiority complex in humans. That will be annoying or even frustrating for humans.
I also want to note that despite our contemporary fascination with intelligence in many cultures people are not really fond of those who are smarter. 'Know-it-all' is a negative term in English. [Dunning–Kruger effect](https://www.wikiwand.com/en/Dunning%E2%80%93Kruger_effect) might be in play here.
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# Intelligence and personality
Intelligence and personality [**are connected**](https://blogs.scientificamerican.com/beautiful-minds/how-does-iq-relate-to-personality/). High IQ correlates with intellectual openness, especially when it comes to intellectual engagement and mental quickness. The article also lists the following traits associated with high IQ (emphasis mine):
>
> 8 dimensions of personality outside the openness to experience domain
> were **positively related** to IQ, including *organization, toughness,
> provocativeness, leadership, self-disclosure, emotional stability,
> moderation, and happiness*-- although the correlations were much
> smaller than with intellectual engagement and mental quickness. IQ was
> **negatively related** to *orderliness, morality, nurturance, tenderness,
> and sociability*, but again, the negative correlations were much
> smaller than the relationships among IQ, intellectual engagement, and
> mental quickness.
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Personality traits not related to IQ are:
>
> gregariousness, friendliness, assertiveness, poise, talkativeness,
> social understanding, warmth, pleasantness, empathy, cooperation,
> sympathy, conscientiousness, efficiency, dutifulness, purposefulness,
> cautiousness, rationality, perfectionism, calmness, impulse control,
> imperturbability, cool-headedness, and tranquillity.
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>
>
These correlations suggest that in addition to superior intellectual abilities aliens will have some tendency to be rebellious and not very inclined to follow social conventions.
When it comes to so-called Emotional Quotient (EQ, aka emotional intelligence), aliens should be not so different from humans. There is some anecdotal evidence that highly intelligent people are less socially adept, but [it is questionable](http://psychology.wikia.com/wiki/Correlation_between_intelligence_and_social_deficiency).
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# Us vs Them
I encourage you to read answers to [this Quora question 'How do people with IQs of 140-200 think, from a social, intellectual, and practical point of view?
'](https://www.quora.com/How-do-people-with-IQs-of-140-200-think-from-a-social-intellectual-and-practical-point-of-view) to see how arrogant can people be when they perceive themselves as very intellectual. It will also provide you with a lot of personal accounts of differences in cognitive process between 'normal' people and high IQ individuals.
One of the fundamental human psychological traits is the desire to divide the world into Us and Them. As you state, aliens are not different from humans psychologically. The differences in intellectual abilities will be very obvious, thus, they will lead to a social division based on IQ. 'He is quite smart for a human' (*in a surprised tone*) would be something that aliens will tend to say about human prodigies.
If your society is similar to the contemporary with its emphasis on high IQ, humans will be reduced to the second-class citizens within a couple of generations. The aliens will be in all leadership positions.
There is no easy way out of this situation. Even if aliens are very caring, altruistic, and sharing, your humans will still have Us vs Them mentality. There must be a fundamental social change for this society to work without discriminating humans or aliens.
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**No.** You really should not generalize to aliens from humans, but since you specifically said the psychology is the same, I'll do it anyway. But I probably should warn that this is unlikely to be true in general.
Luckily the range you specified is below the threshold where people start to really think different and people in this range do not really feel that different. Just smarter and *better*.
They'd see us as slow and depending on their personality they might be patronizing ("They need our help and guidance...") or even abusive ("Since we are obviously better we are entitled to...").
In any case they would IMHO be very annoying for us to deal with not vice versa. They'd probably enjoy having people they can feel superior and smart in comparison to.
Note that among both humans and aliens there would be people considerably smarter than IQ150 and while there would proportionally probably be more such aliens than humans these people would probably associate on a more equal basis.
Which might annoy the majority of aliens, who might not appreciate a lowly human being smarter than they are or getting more respect than they do from the really smart aliens.
But such people are too rare for that to affect the general relationship between the species.
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Keeping in mind that IQ is the ratio of intellectual age to physical age will, I think, help you with this.
There are a few existing relationships within that range you can examine for your aliens: parents compared to their children, professionals in high-IQ professions (medicine, law) compared to lay persons, people to their pets (a 2009 study showed that smart dogs have, depending on the subject area, the same capability as 2, 3, or 4 year old humans)
There is an idea of a "communication gap" past about 30 points of IQ, and that seems reflected in some of these relationships - kids don't understand when adults are talking about 'adult' topics, and some times there are Easter eggs in kids movies for the grown ups that go completely over the heads of the kids. Parents may read books about how to interact with their children, and High IQ professions take classes in communication and technical writing - training to communicate effectively by using smaller words, relational concepts, and pictures. Like the family pet, you can all get along (maybe), but you might consider it immoral for a child to engage in a contract with an adult or gross for a human to treat a pet as a person.
I thought I would edit this to provide some more examples specific to what you had asked. At 130, the gap is roughly that between a high school freshman and a high school senior. At 150, the gap is roughly the developmental distance between a second grader and a high school sophomore.
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This kind of sounds like the TV series "Alien Nation." (It was a movie before it was a TV series, but I didn't watch the movie.)
<https://en.wikipedia.org/wiki/Alien_Nation_(TV_series)>
In what little of the TV series I got to watch (and what I remember from almost 30 years ago), the aliens were smarter than humans, but generally held similar or the same jobs as humans. In fact, the two main characters were detectives, with one being human and one being an alien. The alien tended the solve the crimes, with the human being sort of the comic relief, but the human detective also had to teach the alien about how human minds work for the solution to be found.
Again, this is 30 year old, dusty memories of a TV show I almost never got to watch, so I could be way off. Sorry in advance, if this is the case. It was a good series, so hopefully you'll enjoy researching it.
Anyway, maybe you can take some cues from this series, because, for the record, I'm not suggesting you plagiarize the series and I'm also not suggesting you give up as "already been done."
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Some background information on the setting:
Religion: God is thought of to have dual sides that symbolize male and female virtues. The female portion represents logic, stability, intelligence and control. The ability to access magic was given to her as a symbol of her divine authority. She is called to lead and guide the community in the right path according to God's will. The male side represents passion, courage, honor and emotion. Men are called to protect and defend God's creation and to be its molders and shapers. Only by working together can a balanced social harmony in society be achieved.
Magic: Science and Technology revolve around magic and are used to create a form called magitech. This magic is present in all walks of society. Runes for growing crops, unlimited energy sources that power machinery, teleportals for transportation and alchemy are just some ways magitech is used in daily life. Although everyone has access to magitech, only women can access it directly and create it. Although powerful, magic is limited in significant ways. It is slow, complex and intense requiring much concentration and skill. Attack magic is a rare and specialized field.
One simple way magic is used extends to a woman's biology. All females have the natural inborn ability to control their reproductive functions. They can choose when to get pregnant and can speed up, slow down or pause the rate of gestation. Pregnancy is easy on a woman's body and children usually survive to adulthood. Women who have given birth have access to the strongest magics. Birth fundamentally changes women into a higher being, giving them a higher understanding of magic by being one with the force of creation.
Government: Matrilineal clans are controlled by a women's council with a clan matriarch serving as the head. They are primarily in charge of running businesses, banking, education, hospitals and passing laws. The clan matriarch selects a male chief who is chosen to lead an all male council. They are responsible for security, enforcement, war, defense, exploring territory and manual labor. The chief is more of a servant leader and can be removed by the matriarch if necessary. All clans make up a larger confederacy with an everqueen who is chosen by the matriarchs of each clan. Ritualized gladiator games and competitions are used to replace warfare as a means of keeping the peace between the clans.
Culture: As the bearers of life, women are viewed as the "stronger" sex as they were made in God's image. They are more emotionally stable, rational and able to cooperate to achieve long term goals. Men are valued for their physical strength, bravery and desire to protect others. These qualities make them suited to warfare which is one of the most respected occupations a man can aspire to. However, men overall can be arrogant and egotistical, sometimes allowing their emotions to get the best of them. This belief keeps them out of political power.
Children are raised communally with the clan taking part in raising the next generation. The idea of the nuclear family is nonexistent. Much of child-rearing is left to the younger women and older men. Although children normally retain close relationships with their birth mother, brothers and uncles are the main father figures in a child's life. While sex is not particularly regulated, procreation is. The creation of life is viewed as a sacred form of magic. Cooperative breeding between clans is the norm as a way of securing alliances and trade deals. These arrangements are managed by a clan breeding councils made specifically for this purpose, and are responsible for keeping records and family trees. Successful and valued men are chosen to represent their clans in this way. For women, it serves as a rite of passage and motherhood is celebrated as a high honor. For men, it serves as a symbol of their value and worth to their clan.
The world is under siege from supernatural elements from an alternate dimension that exist alongside reality. It is separated from us by a thin veil which has weakened in certain areas or completely collapsed in others, allowing the things from the other side to get through. War is fairly common with these creatures. This has influenced humanity's development and culture, and encouraged a more complementary, rigid mindset about the genders. There are those that would support more egalitarian, progressive ideas. However, with the hostile environment they tend to get lost in the noise. These people would be viewed as foolish and naive or dangerous at worst. Humanity is focused on its continued survival and that tends to be prioritized over individual liberty or civil rights.
Given the setting, would magical birth control in these circumstances give rise to a rigid, conformist, and controlled society?
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You are overlooking a critical point. Actually, you've conflated it with another. There is no reason to think that women limiting their fertility will (by itself) cause "children usually survive to adulthood." This is (or was) largely a function of childhood diseases and (mal)nutrition. If the kids are dying from diphtheria, diarrhea, pertussis, etc, limiting births will simply result in families dying out. Recurring stressors such as famine/crop failure just increase the problem.
Additionally, having suggested that warfare is the male ideal, the question must be faced of just how much warfare actually occurs and how lethal that warfare is, both to combatants and noncombatants alike. If the average family produces 2 children per generation, a boy and a girl, and half the young men die in battle, and every generation or so a country gets invaded and half the countryside laid to waste, well... the outlook is not good for the culture.
Colonial America, as an example, had an average family size of about 6 children, but half of them died before the age of 5, so the high birth rate was not a cause of the mortality, but a response to it. And this has generally been true right up until the 1800s.
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Birth control does not shrink the population, it [stabilizes](http://www.who.int/reproductivehealth/publications/general/lancet_3.pdf) it by creating [family planning](http://www.rand.org/pubs/issue_papers/IP176/index2.html). Because women become able to better choose when to reproduce you see a shift to fewer and thus high investment children. So you get less boom/bust population fluctuation.
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In societies where women do not control conception and men do not care, women are pregnant as often as they can be pregnant. They have one child after another. This is because men want sex as much as they can have sex. In some such societies a man might opt to control conception for his own reasons; for example ISIS puts their sex slaves on contraceptive shots because pregnant sex slaves are less desirable.
Societal considerations aside, repeated back to back pregnancy is tough on the woman's body and a lot of work. Given just a little bit of control women will often space out pregnancies, try not to get pregnant if times are bad and so on. It is an interesting hypothesis that in humans, concealed ovulation (a woman does not know when she was fertile) evolved shortly after intelligence, because intelligent females sometimes avoided conceiving babies. The ones who did not know when they were fertile had a harder time avoiding conception, and so their genetic fitness was higher and their genes spread.
In societies of subsistence farmers and similar economies, where there is the possibility of regulating fertility but no social safety net and high child mortality, women choose to have big families because they will predictably lose a number to childhood mortality, and because more man / woman power in the family more effectively insures that the family stays fed. Also in old age, should they be so fortunate, the mother and father count on the kids to support them.
In societies where girl children are economically more burdensome than boy babies, families arrange to have fewer girl babies.
In advanced societies where women control their own fertility, the birthrate is low and often too low to fulfill the economic needs of the polity, which then must turn to outside / immigrant populations with higher birthrates to replenish workers.
Your society looks to be one where there will be a lot of community influence which determines whether a woman will bear a child or not. It looks very organized. It will be like China. The central government wanted to limit population growth by limiting fertility and achieved that. Recently they wanted some more population growth and changed policies, and now are achieving that. There are other groups in whom the women are encouraged to have as many children as they can; the Hutterites being one I can think of.
As long as the societal mechanisms you describe stay in place to regulate population it should work fine.
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You've already answered your own question:
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> the faith plays a fundamental role in a person's life. Society is
> conservative and traditional, with the sexes expected to adhere to
> their gender... While sex is not particularly regulated, procreation
> is....Cooperative breeding between clans is the norm, as a way of
> securing alliances and trade deals. These arrangements are managed by
> a clan breeding councils made specifically for this purpose, and are
> responsible for keeping records and family trees. Successful and
> valued men are chosen to represent their clans in this way.
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And you say over and over again that tradition and their specific gender roles are adhered to, which sounds to me like a "rigid, conformist, and controlled society."
However, there will always be outliers, and there will always be people who do not proscribe to those norms. Whether those are allowed and whether these people have a place or not, will be up to you.
There may certainly be communities that see things a little differently.
If war is fairly common and the society decides pregnancy rather than choice--it may not result in a low birthrate, but a high one, but in societies where the government regulates birth there is often an imbalance that nature would correct.
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Whether the population will shrink or grow will mostly depend on the policies the current breeding council imposes.
When women can control their reproductive functions, birth control policies are easily enforceable. Also, magic seems to be able to replicate a lot of industrial-age technology. Maybe even more. This means your society can easily create a lot more wealth than it requires for survival, meaning that your population growth is only limited by the natural resources you have available.
A larger clan is a more powerful clan, but also harder to govern. So every matriarch will decide for herself if she wants to grow, maintain or reduce the size of her clan. Most matriarchs will likely try to maintain a controlled and steady growth of their clans, always making sure that capacities of education, housing and agriculture grow at the same rate as the population. But special circumstances or personal attitude might cause some to deviate from this strategy.
A wise matriarch will likely give instructions to her breeding council like "I want at least 10 babies next year, check who is available" or "We got more than enough mouths to feed. Don't authorize any new pregnancies until further notice".
The fact that a woman gets much more powerful after giving birth, could mean two possible conclusions for the clan matriarch:
* A mother is more valuable for the clan, so every woman is encouraged to have at least one child as early as possible.
* A mother is a larger threat to the matriarch's authority, so only those who have proven to be loyal are allowed to have children.
Which attitude each clan will have will depend on whether the matriarch prefers to rule through popularity or through authority. As Nicolo Machiavelli wrote:
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> Is it better to be loved than feared or feared than loved? It may be answered that one should wish to be both, but, because it is difficult to unite them in one person, is much safer to be feared than loved, when, of the two, either must be dispensed with.
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It would depend on their medical and agricultural technology, this small population would made their best to secure the survival of each newborn, make sure that everyone has enough food, water, decent shelter, and a valuable occupation.
You would have a society that put's incredible value on the life of the individual, maybe they could go so far as to ban the consume of alcohol and other substances that could be seen as damaging.
Another point to think about is migration, if this kind of magic is not common in the whole world, then many women would probably want to move in to this city.
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I wouldn't buy that magical birth control by itself, or paired with increased magic for mothers, would automatically create the society that you describe. But it sounds like a plausible society to evolve in its own right. You don't need to justify why they have the culture they do, and trying to do it is likely to backfire and make them seem less plausible because there are so many different ways that a culture could react to the same things.
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> Given the setting, would magical birth control in these circumstances give rise to a rigid, conformist, and controlled society?
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No, you did that yourself. In fact you have an analog IRL: America in the sixties and "flower children" shortly after the introduction of a "might as well be magic" birth control pill that was cheap (or free). Extensive promiscuity was the result. Without any worry about becoming pregnant, casual sex between young adults became extremely common, even to the point of anonymity: That is a non-rigid, non-conformist, and uncontrolled society.
It wasn't just that the guys wanted sex: Sex is fun and girls get horny too, but in most societies know they will bear most of the burden of pregnancy if it occurs, which tends to make them cautious to engage in sex without some commitment from the males in honoring their fair share of any such consequences.
However, once freed of that burden, and raised knowing pregnancy is their choice, we can expect a shift in their psychology at least part of the distance toward the default position already occupied by males: Sex is pleasurable, fun, and costs no money, so if the only price to pay is in the emotional realm; friendly sex is an option.
All the rigid conformism of *your* society is mandated by you; and somewhat **contrary** to the "natural" result. Cultural behaviors can be traced to costs and consequences, and you eliminated a major cost (unexpected pregnancy without support) that normally shapes a "conservative" society.
My analogy would be you have made the "price" of sex something like the "price" of clever puns, jokes, or card tricks, which are fun and make people happy and seldom have any real consequences. Being good at such puns, jokes and card tricks may get you friends and comrades that enjoy being around you. In your society, were it not for all your religious restrictions, being good at sex (for either gender) might serve the same friendly purpose.
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I would say that the frequent warfare with the supernatural elements would give rise to the rigid non-conformist society that you describe, rather than any birth control. Societies that are at war will emphasise resources that help them win the war (or at least, put off losing the war), and a hierarchical society with a command economy will help ensure that. How extensive this command economy is will depend on the size of the clan and the amount of pressure from the demons; the smaller the clan, or the higher the pressure from the demons, the more they have to concentrate on doing things that win the war.
In this phase of society, magical birth control might be used to emphasise production of male children to replenish the ranks of the armies. It is also the phase of society when men gain more (possibly temporary) privileges, as they're the ones giving up their lives on the front lines, whereas the women are staying in the safety, far from the front line. (If this didn't happen, there might be mutinies; even in a war for survival, there is only so much inequality you can force on those who are going to die for you before they they decide that others should be shouldering more of the burden.)
There will be periods, between wars, where society loosens up and completely changes; this will be in reaction to the war that preceded it. This is when the magical birth control might allow the women to truly put off their fertility and just enjoy sex.
There are other attributes that any society experiencing frequent warfare is likely to have. There would be a tendency towards gathering information about your society, especially during times of war. A surveillance society, where the surveillance is carried out via magical as well as technical and human means, will likely be in place (looking out for demonic agents in society). There might be propaganda campaigns to persuade men that their sacrifice would be for the great good ("Your country needs you!", etc.). There will an intolerance towards alternative views (possibly except in matters of warfare, where if a society is desperate enough, they will consider any options that might lead to a win). All of these would lead to your rigid intolerant society.
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The society you describe sounds like a very "rigid, conformist, and controlled" to me.
You answered your own question.
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I swear I saw this question elsewhere. Let me know if this is a dupe.
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**Photons** are great. They're little bundles of energy that
* **Reflect off of nearly everything**, allowing us to see faraway objects that don't necessarily produce their own light
* Are **practically everywhere**, allowing us to see most of our world
* Are **somewhat easy to detect**
* **Don't kill us** (most of the time)
* **Provide detail** (in the form of colors/different wavelengths)
I'm interested in replacing them with a different particle for a fictional species - but I don't know if anything else matches the above qualities.
**What particles,** real or theoretical, would meet the above criteria well enough to provide adequate vision, besides photons?
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My thoughts so far have been about **neutrinos** (although they are hard to detect), **positrons** (annihilate themselves) and **gravitons** (hard to detect).
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# If it quacks like a duck...
Have you heard of [The Duck Test](https://en.wikipedia.org/wiki/Duck_test), or so called [Duck Typing](https://en.wikipedia.org/wiki/Duck_typing)?
The Duck Test is a type of **abductive reasoning**, and it works like this:
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> If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.
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...in other words the **appearance and behavior** of something determines what we say it is.
Now this may sound silly when it concerns something like waterfowl because one glance at it and we can say if it is a duck or a goose or something else that quacks, waddles and/or looks similar to a duck.
But in the case of something like photons, this becomes decisive, because when it comes to elementary particles it is near impossible to determine if it is a photon or anything else. I mean, have you ever seen an elementary particle and on first glance been able to say "Oh, that's a photon right there... not an electron or a neutrino or a neutron... that is a photon, I am certain by the looks of it"? No you have not, and neither has anyone else.
Phrased slightly differently you asked the question: "what can I have that behaves like a photon, but is not a photon?"
Well... you cannot. Because if it behaves exactly like a photon, then for all intents and purposes, it **is** a photon. And even if it was not actually a photon, there is no way we can say that it is not, so you might as well treat it exactly like you would a photon.
For all we know, "photon" might actually be two, ten, a thousand, or billions of different types elementary particles. But we cannot tell them apart, so we just say they are "photons", all of them.
In short: **we define particles by their behavior, because truth be told: no-one knows what a photon or any other elementary particle actually is. We only know how it works and behaves. And so we say that anything that behaves like a photon, *is* a photon**
So is there any other particle that can behave exactly like a photon while not being a photon? No, there is not.
Hence the question becomes: what other particle could produce something like vision? Well, probably none at all really.
* Electrons... are out of the question because they do not go very far in any kind of atmosphere, and they are hard to emit.
* Neutrinos... do not interact with (nearly) anything so even though they are more omnipresent than photons they are useless as vision.
* Protons... is even worse than electrons because they are stopped very quickly by air. Also they are highly ionizing (i.e. the mechanism that makes radiation very harmful) so you do not want to try to use that.
* Neutrons... are even worse because not only are they ionizing, they also transform atoms they hit into other elements, some of them very unstable, and therefore radioactive.
* ...and so on, down all of the list.
So in short: of all the **known** particles, none do the job of photons as well as photons themselves.
## ...and then there is [Chekhov's Gun](https://en.wikipedia.org/wiki/Chekhov%27s_gun).
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> Remove everything that has no relevance to the story. If you say in the first chapter that there is a rifle hanging on the wall, in the second or third chapter it absolutely must go off. If it's not going to be fired, it shouldn't be hanging there.
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> — Anton Chekhov
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What do you need this alternate vision for? **Is it something that is relevant to the story**, or is it just a fun gimmick you are throwing into the story for the heck of it?
If so: do not do that. Do not throw in stuff that are not actually important for the setting, the flavor or the elements of the story. Readers will quickly see through that and recognize it as a bolt-on filler that does not actually add to the experience.
If you do need it for the story however, then you can make up anything you want. But then you need to make it behave different then photons, because if they radiate like photons, refract like photons, reflect like photons, and make you see like photons do... then they **are** photons.
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**Xenobiology**
Since this question is tagged with "Xenobiology" and "science-based" it is best to keep in mind that *possible* solutions don't equate with *plausible* solutions and that using *real* science terms to explain *unplausible* science-fiction doesn't really do anything to help with suspension of disbelief. (e.g. saying *"the alien vision relies on entangled neutrinos"* isn't much less hand-wavey than *"the alien vision relies on flubulated tachyons"*.)
Making aliens *extremely* unique in their biology in order to avoid inventing more fictional aliens that *"look like us"* is a good habit, as assuming that all aliens (especially the sentient ones) are humanoid bipeds is a laughably anthropocentric of us. However, it is possible to overshoot the mark and make aliens *too* weird to exist by all logical accounts of what we *do* thus far know about physics and biology.
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**Photons:** *If it ain't broke, don't fix it.*
If you have life you have heat, and if you have heat you have photons. Therefore, if you have life you must have photons. There is no escaping this. Photons also interact with the building blocks of matter: the protons, neutrons, and electrons that compose all biological life.
Because photons are so ubiquitous, it is very likely organisms develop some way(s) to interact with them. On Earth this is mostly evident in plants which are able to use the energy for photosynthesis, and most higher-level organisms which posess occular organs which are used to collect directionally-specific photo-sensory stimuli.
While most higher-level organisms posses *eyes* which grant them varying degrees of occular prowess, the fact is that most such creatures detect only certain wavelength bands covering different sections of the visible photon spectrum. Some creatures are rather primitive only having one color-discriminitory sensor, whereas humans have three, and others like the mantis shrimp have as many as 16 types of photoreceptors. Yet other creatures have other forms of photon detection; pit vipers and many related reptiles have infrared-detecting abilities which effectively allow them to *"see heat"* in a useful way.
The *visible* spectrum, as we call it, is actually a rather narrow section of the entire electromagnetic spectrum. Even if you include the infrared heat sensors of pit vipers and the UV sensors of the mantis shrimp, the range of perception for all Earth creatures is still quite limited. Creatures with *visual* acuity in wavelengths to either end of our chunk of the spectrum (either higher energy like hard-UV and X-ray, or lower energy like far-infrared and microwave) would likely see the world quite differently than us, and feel quite alien, while still possessing a type of directional *vision* very comparable to what we're used to encountering- and all without evoking any sort of exotic, non-interactive, or exceedingly rare particles.
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**Additional Options**
*Echolocation (Back-scatter)*
Of course, you might be very loose with your definition of *vision* in the original post. If you're simply asking for another *sense* similar to *vision* without needing that sense to be particularly long-ranged, then *echolocation* is one possibility employed by Earth creatures which could be sci-fi adapted to other methods of propagation.
Rather than the usual auditory clicking noises used by bats and dolphins, any combination of particles could be used in a similar *"ping-then-listen* manner to help understand an area. If the particles in question were photons of X-ray wavelength, then the alien would essentially work like an X-ray backscatter machine found in airports. Unfortunately, the return-trip timeframe for electromagnetic signals is extremely fast, so 3D imaging is unlikely to arise from photon-based detection, though a series of 2D images can create a good guess if you have enough differently-positioned eyes generating pictures to compare/contrast.
Electrons or neutrons could be similarly used, though these pings would potentially cause a significant amount of damage (as the animal basically would be shooting electrons out it's eye sockets like a scanning electric microscope, ditto neutrons). Furthermore, the backscatter is unlikely to be any significant fraction of the output beam. Either way these would be problems. (Let alone describing how a neutron-gun organ developed through natural selection.)
*Charge Sensitivity / Magnetic Sensitivity*
These abilitys occur to varying degrees among Earth creatures, but creating an alien that *sees* a nearby object by looking at its electric charge or mapping it's magnetic fields. To really investigate a surface would involve moving the sensors around to feel the maxima and minima of the fields- which starts looking more like touch than sight, however.
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The great [Hal Clement](https://en.wikipedia.org/wiki/Hal_Clement) came up with something.
In his story [Uncommon Sense](https://en.wikipedia.org/wiki/Uncommon_Sense), the animals have eye-like structures that are globes with pinholes.
In a vacuum, any molecules given off by something will travel in straight lines, so smell works like sight! The pinhole provided image forming of the scents coming from objects just as reflected light does for us.
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Vision is interchangeable with other sensing faculties, it's well known in the Buddhist teaching. Apart from using light/reflection/eyes to gain information, audio, smell, taste, touch are also working in the same way, but just the channel for the input is different. Thus in Vimalakirti Sutra it described a world made by smell/scent, even the buildings and clothes, all are made by scent, so is the language they used to talk to each other. There is another world called Realm of Brilliance of Sound. In it the language is communicated via light, not sound; the food is thought, not milk or bread :).
However, it maybe sexier to think up a term belongs to the physics' terminology or like. It's interesting scientists used "flavors" to attribute neutrinos.
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I could imagine Neutrinos being used by something HUGE that needed to "see" things on an interstellar scale. This might be out of scope of your question, though, if your alien species is more analogous to earth-life than, say, a lovecraftian planet-sized space-whale.
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I'd like to include a locale in my world that would be a massive glass crater in the middle of the desert. Originally, I imagined an orbital laser cannon or solar "Icarus"-style weapon from the mediocre James Bond movie, "Die Another Day", firing a concentrated blast of energy that would both melt the sand and blast the sand away to make the glass form into a crater.
-Would either a laser or solar mirror be able to get hot enough to melt sand into its liquid form(at least 1700 degrees C)?
-If the temperature is attainable, can a beam impact the sand with enough force to actually cause a blast crater?
-How would a weapon this strong impact climate and the environment? My guess is the atmosphere would get a hole torn in it.
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# Yes, We Can Melt It.
You can use mirrors or lasers to melt sand. Doing so from orbit is a bit over-the-top and impractical. Not only do you need to deliver the energy to melt the glass, but you first need to get the energy past the atmosphere (which would involve heating that up to or above the target's melting temperature), and then you need to deliver that energy and move the soil out of the way!
# Let's do Some Physics!
We need to know a few things first. I'm assuming the sand is made of mostly quartz, or $SiO\_2$, even though real glass has a bunch of other things in it.
* The [heat capacity of (quartz) sand](http://www.engineeringtoolbox.com/specific-heat-capacity-d_391.html) is about $830 \frac{J}{kg ^{\circ}C}$
* Sand melts when heated to about $1700 ^{\circ}C$.
* The heat of fusion for sand is... actually really hard to find! I've found an [enthalpy of fusion](http://adsabs.harvard.edu/abs/1982GeCoA..46.2639R) for quartz to be around $9.4 \frac{kJ}{mol}$ Using the [molar mass of silicon dioxide](https://en.wikipedia.org/wiki/Silicon_dioxide) ($.06008 \frac{kg}{mol}$), I figure the latent [heat of fusion](https://en.wikipedia.org/wiki/Enthalpy_of_fusion) for sand is about $156 \frac{kJ}{kg}$.
# How Much Sand?
I'm going to do my calculations for 1 kg of sand. You'll need to figure out how much glass you're making on your own.
# Making Glass
Using a simple $Q=mC\_p \Delta T$, and thinking this sand is already in a hot desert (~40C), the sand requires 1.378 MJ just to get to melting. To completely melt, the sand requires another 156 kJ, so it takes 1.534 MJ to melt a kilo of sand into glass. This calculation does not include penetrating the atmosphere, or any cooling effects at the target.
# Impact Craters?
[Here is a nifty](http://keith.aa.washington.edu/craterdata/scaling/index.htm) crater calculator. Modeling this weapon as an explosion above the surface (with the equivalent energy of 0.0003667 Tons of TNT), this calculator says the surface crater is a measly half a meter, and only 15.6 cm at maximum depth! Even so, any energy we use to make the crater is less energy we use to make the glass.
In any case, this calculator can be used to estimate the energy needed to form a crater. It should be noted that the [Trinity test](https://en.wikipedia.org/wiki/Trinity_(nuclear_test)) did melt sand into a green glass, and it had a payload of 84 TJ. Its crater was only 1.5 m deep and 9.1 m wide.
Given all this, it seems an orbital glass maker may be able to make glass, but it will not form a crater without ridiculous amounts of energy!
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A nuclear bomb is probably your best bet. Then wait until the radiation goes away (sadly not an option in reality, but when you are preparing a planet before there is any life on it...).
Using a bomb with many stages you should be able to scale the explosion as much as you want (nobody tried this in reality, because thermonuclear bombs with two stages are already huge enough).
Existing thermonuclear bombs are around 10^16J, so by scaling this up massively using like 10^4 "stages" (blobs of radioactive stuff which are almost critical in size) this sounds doable (when using the energy amount kindly calculated by Joshua in the other answer).
On the other hand using the data (from the other answer) about the Trinity test saying that one thermonuclear bomb generated a crater of around 10m in diameter and assuming that energy is more or less proportional to the square of the diameter, then with 10^4 times the energy you should get a sizable crater around 10m\*sqrt(10^4)=1km in diameter.
This seems to be more or less coherent, and that's all I aimed for. Should be in the right ballpark.
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For a real life example read up on [Libyan Desert Glass](https://www.temehu.com/libyan-desert-glass.htm).
Located in a 60x100 kilometer area on the Libyan/Egyptian desert, the glass is scattered over the area. Various theories have been put forward as to its source. From ancient nukes, to an air-burst from a meteor or comet. Fairly recently, a very weathered, very large crater (30 km) has been found that could be the remnants of an actual impact.
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In answer to your question about the amount of energy required, let's say the amount of sand that was melted was 1 cubic mile's worth. That translates to 4.168e+9 cubic meters. Using the measurement for the mass of dry sand (<http://www.simetric.co.uk/si_materials.htm>), we are given 1602 kg/cu.m
That translates to a total of 6.677e+12 kg of sand. A rough estimate of the energy required to melt 1 kg of sand into glass (<http://www.lowtechmagazine.com/what-is-the-embodied-energy-of-materials.html>) is 18-35MJ, depending on various elements involved in the process, type of sand, etc. Taking the lowest possible from those figures, at 18 MJ per kg, you're still looking at a TON of energy required, at **1.202e+14 MJ**, or **3.4e+16 watt-hours**.
I don't think we have anything even close to the tech that would be required to do what you are asking, at least not in the span of a few seconds or minutes. The solar mirror would be your best bet at a realistic possibility, because it uses "free energy", instead of something that has to be compacted into a laser. As for the looks, I would conjecture that the process, if feasible, would look like an upside down glass volcano. I would love to watch that!
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Linear Acceleration: A form of transit in space flight where a spacecraft points toward a destination and accelerates for half of the distance it needs to travel, then decelerates for the other half, currently not viable due to the high amounts of DeltaV and fuel required.
I'm working on a Sci-fi universe where due to humanity's lack of gravity manipulation technologies (BS artificial gravity plaiting, anti-gravity, etc.) human ships are oriented like towers (Engine being like the foundation, decks being different floors) and use Linear acceleration to mimic the sensation of gravity in space. (yes I did get inspiration from the Expanse)
Qualities im looking for:
1. high fuel efficiency
2. capable of acceleration of 9.8 m/s^2 or higher for days to years at a time
3. the shorter the structure, the better (no kilometer-long metal structures, as flipping halfway for deceleration would cause high amounts of stress on the craft that could tear it in half)
4. Optional: cool as all heck
5. Also optional: doesn't involve super-hypothetical tech (Such as small artificial black holes)
6. Technology at this point is to where fusion reactors are possible to build and maintain for long periods of time and Mankind is close to antimatter technologies (synthesis, reactors, etc.) and basic FTL (akin to a warp drive) (FTL is used to jump between two points in space nearly instantly but is incredibly dangerous, thus traditional space travel is used for interplanetary distances and traveling to jump points)
7. The distances travel range from between Earth and the moon to Earth to the farthest parts of the Kuiper belt
8. The engine can be turned off and on a near infinite amount of times (a common problem with current rocket technology is that engines can be ignited and shut off only a set number of times)
9. **RADIATION IS NOT A CONCERN FOR ME** As long as it can be shielded against, as these engines are only used in space.
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From the question I'm not sure if you are looking for a scientifically realistic answer, with not involving super hypothetical tech being optional and all. If not, there are plenty of fictional options, e.g. the Epstein drive from The Expanse. It's described as being fusion powered, but how the drive as a whole works is just handwaved, and not possible with currently known technology.
If you are looking for something scientifically realistic, an answer that's still missing here is the [**nuclear salt water rocket**](https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket). Nothing like it has ever been tested, but the design is based on powering a rocket with a continuous nuclear reaction. According to the Wikipedia page,
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> The design and calculations discussed above are using 20 percent enriched uranium salts. However, it would be plausible to use another design which would be capable of achieving much higher exhaust velocities (4,725 km/s) and use a 30,000 tonne ice comet along with 7,500 tonnes of highly enriched uranium salts to propel a 300 tonne spacecraft up to 7.62% of the speed of light and potentially arrive at Alpha Centauri after a 60 year journey.
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I haven't done the math on how this works out for linear acceleration in the solar system, but with the above I'd guess it is at least in the neighborhood.
**edit:**
Reading your requirements again, having a somewhat serious proposal in the current scientific literature doesn't seem to be the tech level you're aiming at. If they have experimental antimatter and warp-like technologies, they probably also have [direct thrust fusion rockets](https://en.wikipedia.org/wiki/Fusion_rocket#Electricity_generation_vs._direct_thrust). A deuterium - helium-3 fusion rocket has an exhaust velocity just above 21,000 km/s\* assuming 100% conversion efficiency. Using magnetic fields to confine the reaction and direct the reaction products shouldn't be a problem, and should help with the longevity of the engine. According to [Scott Manley](https://www.youtube.com/watch?v=JWZqp0QoXcw), the Expanse's Epstein drives would need an exhaust velocity of 10000 to 15000 km/s, so this is perfectly in the range. Scott discusses that an Epstein drive fueled by deuterium - helium-3 fusion would still emit part of the fusion energy as energetic neutrons and hard X-rays and that would be enough to melt the rocket, so you'll need some science-fictional technologies to improve the efficiency and reduce these side conversions, but that doesn't seem more difficult than handling antimatter and FTL.
Small scale versions (where the heating is manageable, but thrust and exhaust velocity are much lower) of such direct thrust fusion drives are actually [being researched](https://en.wikipedia.org/wiki/Direct_Fusion_Drive). You just need to scale it up.
So at the tech level you seem to be targeting, something like Epstein drives are perfectly possible.
\* Calculated by converting the energies of the reaction products (3.6 MeV for the alpha particle and 14.7 MeV for the proton) to their velocities and taking a weighted average. If you are able to (magnetically) split the alpha particle and proton streams and transfer energy from the protons to the alpha particles so they both have the same velocity, you can get an even higher average exhaust velocity. If you have technology to ensure neutrons are emitted in the right direction or can be redirected, deuterium-tritium fusion gives about the same exhaust velocities, but then you need to deal with neutron radiation in your rocket exhaust.
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TL;DR: rockets are limited in many ways. You can have high thrust, or high efficiency, but trying to combine the two does not work well if you're constrained by real world materials and physics.
Don't use rockets to provide artificial gravity.
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With rockets, this means high exhaust velocity, and good ways to get stuff moving fast are nuclear reactions. These are doubly useful in that they provide the energy to their exhaust products, so your fuel and your reaction mass are the same thing, which makes the plumbing easier.
Fusion reactions have products shooting out at up to 10% of lightspeed. Antimatter annihilation has stuff coming out faster, but for complex reasons is doesn't end up being quite as good as you might think.
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The former is very, very tricky. The latter is stupendously difficult.
The problem with rockets with very high exhaust velocities is that they tend to be low thrust. If you can scale them up (and not all designs scale up well), then you have the problem of them requiring huge amounts of power, and hence huge amounts of heat.
*Really* huge amounts of heat, and *really* huge amounts of power.
The thrust power of an engine is $F\_p = \frac{FV\_e}{2}$ where $V\_e$ is exhaust velocity and $F$ is the thrust in newtons. A 1000 tonne spacecraft accelerating at one standard gravity has a thrust of 9.81MN. With an exhaust velocity of 5% of C, that means a thrust power of ~74 terawatts.
Super-high-power nuclear rockets are also notoriously inefficient. Antimatter rockets lose >30% of their power output to hard gamma radiation. Fusion rockets lose at least 25% of their yield to x-ray and neutron radiation. That means carrying around huge radiation shields, and vast heat radiators to stop them melting.
But lets get back to your "years at a time"!
That gives you *two* additional problems.
Firstly, accelerating for a year at 1G gives you a velocity of about 0.72c, (including relativistic corrections). That means every gram of space debris you hit has the energy equivalent of 9 kilotonnes of TNT. Think about how easy it is going to be to armor you ships against that sort of punishment.
Secondly, now we've established that both Newton and Einstein hate your ideas, Tsiolkovsky gets to join in too. The [relativistic rocket equation](https://en.wikipedia.org/wiki/Relativistic_rocket#Relativistic_rocket_equation) says that a fusion drive with a 0.05c exhaust velocity needs a mass-ratio of >70 million... that means that each gram of dry mass of your rocket, you need 70 tonnes of fuel to run that rocket for a year.
You can use antimatter instead, which needs a mass ratio of merely 15, but that comes at a cost of a thrust power of 485TW, and to achieve that you're emitting hundreds more terawatts of pure gamma radiation which needs massive shields and even more huge heat radiators to stop them boiling away in an instant. Also, carrying around kilotonnes of pure antimatter has its own risks.
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[](https://i.stack.imgur.com/nH2ik.png)
Cool is subjective. I like the 2014 Firefly design from Icarus Interstellar... its awkward to get free papers about it anymore, but [Project Rho](http://projectrho.com/public_html/rocket/realdesignsfusion.php#id--Firefly_Starship) has a nice summary. It should give you a good idea of the scale of the heat radiators that fusion rockets need. It would have a thrust measured in centigees, and a payload of ~150 tonnes for many tens of thousands of tonnes of starship. It is a pretty realistic design.
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Just use that for long distance travel. Forget using rockets to provide gravity... physics just won't let you do it nearly as well as you'd like.
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# [Ion engines are the best](https://www.nasa.gov/centers/glenn/technology/Ion_Propulsion1.html)
Ion propulsion is what is used on satellites. It's extremely fuel efficient, since you're just shooting out xenon at extreme speeds. You don't need massive tubes. It's easy to turn on and off. And you can scale it up a lot.
The main limitation for them today is power. We use solar power to power them, and solar power doesn't have that much power. With fusion you can power massive electromagnets that move ships at huge speeds.
If you want a larger explanation on this, [this answer on space.stackexchange](https://space.stackexchange.com/questions/8599/can-ion-thrusters-be-scaled-up) explains how the main limitation on them is the limited power solar energy provides, not other things.
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If you're looking for a physics-compatible answer that doesn't require any extreme technologies, I'm afraid you're going to be disappointed. The tyranny of the rocket equation is functionally unassailable.
Firstly you're going to need a lot of reaction mass. No matter how efficient and powerful your drive, you still need stuff to throw out the back to make you go forward. And the more reaction mass you carry the more you need to carry to accelerate the fuel mass along with the rest of the ship. This is a losing game.
We can flatten out the exponential curve a little by throwing more energy at the problem... right? Well, yeah, but there are limits here too. The more power you need to produce the bigger the reactor needs to be. And for fusion reactors (at least the ones we're working on now) that's an exponential growth in mass against a linear growth in power output. Not a problem for a Tokomak sitting under a mountain somewhere ground-side, but when you're trying to provide power to move a spaceship the reactor's mass is kind of a big deal. And of course you need a supply of deuterium and tritium (none of this protium trash) for the reactor, or maybe some enriched lithium for a breeder blanket to supply the tritium... and so on. A couple hundred tons of reactor is a pain to move around at the best of times. Getting it to produce enough power to lift itself at 1G, even ignoring the mass of the engines and various fuels, is simply bad SF for the foreseeable future.
Basically no matter how you look at this problem you'll find Physics standing there in a "Newton Rocks!" t-shirt, swinging a ruddy great club labelled "The Rocket Equation" around and grinning evilly. Or possibly doing an impression of Sylvester Stallone as Judge Dredd drawling that classic line: "I *am* the law!"
Because Physics can be a bit of a dick sometimes.
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Still here? My, aren't we persistent. Or masochistic. Maybe both?
A lot of very smart people (no not me, *actually* smart people) have given this problem plenty of thought and come up with a few possible options. The best we've managed to come up with to date in terms of efficient, high power propulsion is the same thing engineers have been doing to tricky problem for centuries: blow s#!t up. If that doesn't work, blow s#!t up *harder*.
(Which, now I come to think about it, is already the foundation of rocketry.)
I present to you: [the Orion nuclear pulse drive](https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)). This baby uses a series of nuclear (fission, not fusion) reactions as thrust. Sub-kiloton nuclear munitions are fired at about one per second, half of the explosion pushing against a pusher plate which transmits force through a series of shock absorbers to the body of the ship. With proper tuning you can get up to 4G pretty easily, and keep it up for a fairly long time.
Of course it's dirty as hell and you'll need quite a bit of shielding if you want to arrive at the outer planets with hair and germ cells intact. Never fear though, we have cleaner alternatives: Inertial Confined Fusion. Still blowing s#!t up, just with slightly cleaner fusion products and a greatly reduced "glow in the dark passengers" factor. Same basic idea, just using terrawatt XFEL or NDPG lasers (ask the NIF - they love this stuff) to touch off enriched deuterium/tritium ICF pellets. Might be lower yield per pellet, but you can fire them off more frequently... which gives a smoother ride, am I right? And since the resultant helium plasma has a charge we can use magnets to shape the exhaust, so it might even be more efficient and controllable. And it's a hell of a lot lighter than a Tokomak too.
Take that Bussard! Your ramjets might have the range, but we have more "blowing s#!t up" per ton than you'll ever have!
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Paraphrasing Elon Musk: The best mass is no mass; the best motor is no motor.
The only viable option for interstellar travel are tiny, very light [probes driven by a ground-based laser](https://en.wikipedia.org/wiki/Breakthrough_Starshot) shining at their light sails. Colonization of exoplanets is done by RNA/DNA only (like it happened with Earth, back then).
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## Dry Nano-Particle Field Extraction Thrusters
[Nano-Particle Field Extraction Thrusters](https://en.wikipedia.org/wiki/Nano-particle_field_extraction_thruster) are to date the most powerful electric propulsion systems invented being hundreds of times stronger than traditional ion engines... but they are still a long way from being as optimized as they could be or achieving 1G of thrust.
They work in principle similar to an ion engine, but instead of noble gases, they use carbon based nano particles. Because of the unique conductive properties of carbon latices, and the ability to shape them however you need them to best meet your goals, you can use carbon nano-particles to achieve far greater thrust than ionized gasses, but more importantly, because there are infinite possible shapes to a carbon nano-particle, you can easily handwave in "better shapes" as an excuse for why your NPFETs produce more thrust than modern ones.
That said, there are a few engineering hurdles in the design of modern NPFETs that we already know that we can improve on by solving specific problems. The biggest is the Wet-NPFET problem. Carbon nano-particles are a solid, not a fluid; so, getting them to the charging pad is difficult. The primary solution for this is to mix them with a liquid, but then the liquid adds wasted fuel mass and tends to build up on the charging pad significantly reducing its efficiency. It also aligns the nanoparticles randomly whereas a solid fuel could align them with the charging pad taking better advantage of shape optimization. In theory, a Dry-NPFET thruster will produce much more force, but there is very little published experimental data on such designs because there are no published mechanisms for feeding one... the good news is that you don't have to delve very deep into science fiction to come up with a solution for this.
Graphene is an incredibly strong 2-dimensional crystal that can in theory be processed into sheets that are only 1 or 2 atoms thick, but tough enough to hold several pounds of weight. If your ship were have a sort of high-speed graphene printer, it could have a graphite fuel tank that is used to print a continuous sheet of graphene interlaced with the sort of carbon nanoparticles you need. You could then feed this sheet over the charging pad like a cassette tape repelling the heavier, weakly bonded nanoparticles harder than the graphene causing them to be ripped from the sheet and expelled as a super high velocity reaction mass. If you build your charging pads in pairs (one positive and one negative), you could then feed the waste graphene strips into each other to neutralize their now significant electrostatic charge. The strips can then be reloaded with new nano particles or recycled into new strips if damaged.
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**Rock plasma rocket.**
This very long and awesome rocket collects rocks and asteroids. Junk from the crew can also be put in the hopper as well as waste material and whatever else you have. It is fuel efficient because this stuff is fuel only for the rock plasma rocket.
You have fusion power. You use the fusion power to heat the trash to plasma. Plasma is charged particles. You use your fusion power magnets to accelerate the charged particles out the back. You can add various things to the hopper to color your plasma different colors if you want.
You are very long; yes very long indeed. Some say too long but you will remind these folks that it is not how long your ship is, but what you do with it. There will be no flipping; nay. You move like the graceful dancer you are, slowly pirouetting about your great length such that forces balance and all remains well despite your extreme to the point of impracticality longness. Your ship may groan a little with the strain. That is still ok.
Oh, xenon. Xenon! Yes xenon is fine reaction mass for deep space probes out in interstellar space. Tiny probes where cargo area is at a premium. But the farthest that the Rock Plasma Rocket is going to go is the Kuiper Belt! That is right up the street! The planned routes for this rocket are liberally strewn with reaction mass free for the taking and there is plenty of space on board to store it because this rocket is seriously long.
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## Beamriders
A beamrider is a spacecraft using externally produced energy to accelerate. It is free of the limits of the rocket equation. I've seen proposals that could do 24h Earth-Mars transfers (with human-compatible accelerations), and aren't that sophisticated on the technical side. The basic idea is that you have the fuel come to the rocket. How do you do that?
Take your pick:
* Sunlight- or Windsail: Those are the most well-known version; those concepts have been tried already. You use the sun's light or particle emissions to propel yourself, but this is rather slow. Check out sun-diver mission concepts to see the limits of this approach.
All of the following approaches require magnetic fields as rocket nozzles. This gives you an interesting opportunity because the fields don't care if the plasma they reflect was created by the energy a distant beam station sent you or if you've just thrown a nuke out behind you. Look up Mini-Mag-Orion for the basic concept.
* Bomb Trail: Use Lighsails or Mass drivers to position fission, fusion, or antimatter bomblets in a long arc along the trajectory you want to travel along. The initial stages require actual bombs, but once you've reached about 100km/s of relative velocity, you can drop a small mass in the path both the bomblet and the fusion reaction will ignite itself.
* Particle or Macron Beams: Those are a tad hard to keep focussed, though options exist. Especially cold, laser-coupled particle beams could stay coherent over several AU. Particle velocities of those systems can be measured as significant fractions of c if the theology is advanced enough.
* Lasersail: Breakthrough Starshot is the best-popularised version of this concept. The fact that it is considered for interstellar missions illustrates the power level involved. You can use power satellites near the sun to generate the energy you need. However, lasersails suffer from a number of serious drawbacks. Titanic lasers, mirrors, and sails are needed. The solution:
* Sailbeam: Instead of dragging the vessel along with a light sail, you use small sails, which can get very fast quickly. Those sails are then vaporized by a shipboard laser or by colliding with a target mass. The plasma is then reflected in the magnetic sail.
Sailbeam is great for a number of other reasons as well. It requires less infrastructure than pure lasersails, and has a greater range, especially if relay stations are used. The system can be used for more than just spacecraft propulsion. It can be used to export solar energy from Mercury. The same magnetic reaction that drives the spaceships can be used on stations and planets as a magnetohydrodynamic generator. Incidentally, this allows you to move asteroids, and you could set up sail beam relay stations in the Kuiper and Oort regions if you have relativistic interstellar intentions.
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So I was thinking about the possibility of a Pangaea like landmass in a secondary world setting. Assuming more or less historical technology and humans, how would the concept of a navy and maritime trade evolve in a world in which nearly all major nations are attached to the same landmass?
While the sea would still be a valuable means of trade in the early days, would it still be as valuable once railroads could be developed across the landmass itself?
Similarly, would naval power really have all that much value if nations can just attack each other over land?
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After looking over maps of Pangea, isotopic rain fall estimates and mountain ranges. It's easy to see that a robust maritime presence would actually flourish.
Especially in the relatively shallow Paleo-Tethys Ocean where it is cradled within the super continent. Early "shoreline" traffic would be likely if we compared the area to geographic present day Mediterranean, or Indonesian waters that it resembles.
Great deserts bordering the equatorial tropical region accompanied by their mountain ranges, would hamper railroads, and overland trade. Though in time that would be overcome it's doubtful that would seriously threaten the dominance of sea trade. As in any society today, populations have always gathered on water. I see no reason they would not on a Pangea content.
With populations, come the need for trade, trade requires infrastructure, infrastructure requires protection and becomes strategic. Those populations would be on the coastlines. Navies would be just as essential as they are today. As I stated before the great north and south deserts would be formidable barriers for quite some time, there is evidence of a tropical region dividing the two that would be quite inhospitable for most of the year as well.
I do realise the OP stated "Pangaea like landmass". How similar isn't stated so have based my answer on Pangea itself. Geographical conditions my sway any answer one way or the other. And depending on how the geographay is formed it can disfavor sea travel greatly. In the end however, the same conditions apply. Populations will center on coastlines, then spread inland. There, in all likelihood, will be a northern and southern desert bordering a tropical wet summer monsoon like area on the equator that will greatly inhibit transit. And the best way to get around will still rely heavily on the waters.
As for the rest of the water world, there would be little reason to travel there, unless there were more shallows there to encourage gathering of life for fishing etc. One could imagine great industrial ships semi-permanently out to sea in far distant oceans servicing fishing fleets. Like mobile boom towns on the water.
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For most of its history, sailing has been limited to the proximity of the coast: in such a scenario, the starting point and the early development will be the same. True, Polinesians have spread through the Pacific and that's not exactly coast sailing, but once they settled on the islands they did not start trading networks across the oceans.
The divergence point will be where in our timeline we developed ships capable of crossing the ocean in a reliable way: one thing is crossing the Atlantic and from there the Pacific with the learnings from the Atlantic, another is crossing approximately the length of Atlantic and Pacific "first time right".
Even though railways might be available, navigation can still be advantageous: think of a gulf or a fjord: crossing it with a ship can be competitive, cost-wise and time-wise, with going around its coastline in another way.
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# The Age of Big Ships:
Paradoxically, such a world might drive the construction of bigger and faster ships. Trade will still be vitally important on your world. Pangea was far from a round ball, with lots of ins and outs. Shipping by water will be critical. But with a big mass of land between destinations (with no narrow points for easy overland trade), there will more, not less pressure to ship long distances.
The same pressures that led to the construction of [Clipper ships](https://en.wikipedia.org/wiki/Clipper#:%7E:text=A%20clipper%20was%20a%20type,a%20large%20total%20sail%20area.) would be at play on your world. To get between distant locations, you need ships that travel long distances. Forces that let you do this faster, with more cargo and less crew will increase the pressure to have clipper-like ships.
Inland, you'll still have to deal with mountains, deserts, great rivers and hostile nations. Long-distance rail shipping is still not going to be as cheap as ships.
You may have a greater drive in the age of rails to develop shipping containers, speeding the transition of ship-to-rail and back, since fewer destinations can be directly reached by trucks and wagons from ports.
Finally, there might be a higher emphasis on developing products that can tolerate long ocean voyages (or slow transits across the land). For example, [India pale ale](https://i.stack.imgur.com/d9s2Y.png) was specifically formulated to survive the voyage from England to India.
[](https://i.stack.imgur.com/d9s2Y.png)
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[Fishing rights.](https://en.wikipedia.org/wiki/United_Nations_Convention_on_the_Law_of_the_Sea)
A 190 ton Blue Whale's weight is 20% bone, this leaves us with 152 tons of blubber and muscle plus assorted guts and organs. Enough for 100,000 meals? Perhaps more. Other whales are smaller, but still constitute larders with fins.
I don't suppose that I need to go into fish value, a good hold full of assorted fish could weigh in at tens of tons, even for a medieval boat. To feed a large city on the coast, it'll definitely be worth protecting. (Salt for preservative.) Also see: [Cod Wars](https://en.wikipedia.org/wiki/Cod_Wars)
Then there's the sea-bed, flatfish, crustaceans and assorted molluscs are sure to be a delicacy for the scarcity caused by the difficulty of obtaining them (snagging nets on rocks etc..). Once fished-out, new beds must be found or poached.
It goes without saying that since the sea and sea-bed vary in their bounty for several reasons (eg. continental shelf width/depth, warmth of currents - like the Gulf-stream) that good waters are going to be in demand - and worth a lot to whoever owns them - and to whoever wants to poach from them. Having a stout navy seems the obvious solution both for individual stray boats and organised invasions of fishermen with their eyes on the main chance.
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**The impact will vary through the history of this world**
1. Ancient era. Prior to discovery of magnetic compass and celestial navigation, ships were mostly bound to routes close to the shore. This will be no different in "Pangaea world".
2. Development of high seas navigation will allow to cross the big ocean and establish trade routes between far countries. However, this would be more difficult than it were on Earth. Required trip is much longer than even crossing of the Pacific today, and many aspiring Columbuses are going to perish on this journey. Magellan's success should come later than 1520s (because there would be no successful Columbuses to build upon their success, though there well might be successful Vasco da Gamas). Once cross ocean route is established, exploration and trade will flourish, but there unlikely be massive colonization, like it happened on Earth. Colonial powers would have to deal with large indigenous populations that are not so much behind them in terms of technology (think India and China).
3. The age of sail will proceed with its development more or less like it happened on Earth - there will be bigger and faster trade ships. For the navies, however, massive developments are unlikely, because sending navy fleet across the big ocean would be prohibitively expensive. So likely there will be "East" and "West" maritime theaters, and countries on the other side of the continent would not likely be threatened by any distant powers.
4. The age of steam should make massive cross-ocean military operations feasible, which may lead to building massive fleets and Pangaea world's "World War I", with many naval battles. Commercial shipping should be more or less what it was on Earth.
5. The age of globalization can be actually fastened. There will be a pressure to build cross-continent rail lines, because sailing through the big ocean or around the continent can be a much, much longer route. It's much better to ship goods 4,000 km on rail vs 500 km rail, 35,000 km ship and 500 km rail again. What is required is a an effective transcontinental railroad. Our existing Trans-Siberian railroad (built in early 1900s) is not effective for shipping across multiple state lines - but this can be definitely improved, if those states are all focused on this task.
By modern era, this world would feature many ships that are larger than our Earth's ships and better suited for long journeys.
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I don't think you have to look much further than current earth. Asia-Europe-Africa are already kinda as big as a super continent, and look at how much rail transport there is between China and europe. Answer : not much, if at all. Most of it goes through container ship. The Suez canal help obviously, but even without it would still be worth it.
The only thing that could prevent it would be difficult navigation. If your continent extend way north and south, it could be blocked by iceberg. Or maybe there could be some constant storm somewhere along the way. Note that it could lead to a mix ship / railway. Instead of using railway deep in the continent, ship to a place like panama pre canal, railway to the other side, board ship again.
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I don't think it would be all that different from our world.
Sure, it would *in theory* be possible to take an overland route from any place to any other place. **But that route is not necessarily safe and convenient**. Maybe the terrain is covered by mountains or dense jungle that makes it too difficult to build a road or railroad. Maybe there *is* a road, but it's a popular hangout for highway robbers or hostile enemy soldiers. Or maybe the coastline just has a concave shape with a bunch of peninsulas and inlets so that a water route is just plain *shorter*. (Analogous to a Morocco-to-Spain traveler in our world taking a ferry across the Strait of Gibraltar instead of taking the long way around the Levant and Black Sea coast.) So there would still be justification for transporting people and goods by ship.
And offshore *resources* would still be a thing: Fish, whales, shellfish, oyster pearls. Perhaps most importantly, oil and gas fields. People and countries would want access to these things. Having a coastline may be even *more* valuable than in our world, because there's simply less coast in the world.
The main point of difference is that, once shipbuilding and navigation has advantaged to the point to make an Age of Exploration possible, someone wannabe Magellan is going to set out to answer the age-old question “What's on the other side of the world?”, and return to Pangaea with the disappointing answer of “nothing”. With no “New World”, there are no massive colonial empires like the Spanish or British had in ours. As such, [blue-water navies](https://en.wikipedia.org/wiki/Blue-water_navy) don't have much of a reason to exist, and military vessels generally stick close to home defending coasts or rivers.
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How could be a Pangea with a land area similar to the total area of emerged land we have today?
The perimeter and therefore the coast of such land would be smaller. Less space for the rivers to outflow in the sea. There could also be less mountain if the tectonic plates were side by side with less overlaps. This would result in a land with long and wide rivers. and a lot of marshland.
Since history begun until the invention of the railway transport by boat was the most efficient one and often even the fastest. I can bet that a route going via one river, the sea and another river would be faster that the direct route through the marshes. But that's not the only case, sometime a long route might be needed to go around hostile peoples or other obstacles. So maritime trade is absolutely possible.
Once you have maritime trade you also have piracy and a navy to defend from the pirates. In theory you could reach the pirate bases by land, but the pirates could have some impassable fortifications on the land side of their cities. Or the pirates could be smart enough to cover their traces, with many city states that would be easy and without a navy the traders could not understand where the attacks come from.
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In a pre-electrical age, anyone who needs a mobile source of illumination must rely on a lantern, lamp, candle or torch. Torches seem to be the cheapest, most primitive option, yet surely they have some variation in design just as the other light sources vary across eras and cultures.
What are the most advanced torch designs? Surely the original, most primitive torches were just sticks pulled from the fire, but you could do better than that. Any help would be appreciated.
Edit: I'm interested in this question because I am writing a story that involves cave exploration. For dramatic purposes, I like how iconic torches are: an open flame, held like a sword against the night. Yet it seems to me that any practical-minded spelunker of a society in the age just before electrification would prefer a lamp over a torch, since a torch is improved in every way by a lamp, assuming you have the resources and technology to produce one.
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# Oil lamps
Just before electric lamps we used oil a lot. We even had people refilling and lighting the lamps when night set in.
An oil lamp is one of the most advanced ways to have a torch. A torch is basically a stick on fire, but can be augmented by oil in rags around it. Logically you take the burning torch to an extreme.
The oil used for the torch is put into a reservoir. A wick is added, closing off the container after a fashion. Via capillary action it'll drench the wick. If you put fire to it, extra processes besides capillary action will keep the wick drenched in oil. As long as the oil is on the wick, it'll not (or more often hardly) burn the wick. It can also be used in many orientations without affecting the flame too much, allowing its use on ships for example.
This will allow an oil lamp to burn efficiently with high regularity until the oil is gone. You might be able to also increase and decrease the oil supply by using pressure on the wick, allowing more or less oil to pass to the wick. This can help regulating the size of the flame.
Further augmentations are glass panels to control air flow and prevent the flame from going dying thanks to the wind. It also protects against rain and other weather conditions. You can focus the light beam with shutters and different kinds of glass/lenses. Tiny glass allows for colours.
The box it comes in can have many kinds of gripping mechanisms, allowing the mounting nearly everywhere. On a lantern, a pole, a ring or just in your hand. All relatively safe, stable and made for their use case.
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Hollywood has long used link-type torches in movie production -- an expendable or non-expendable handle with an optional metal end, around which is wrapped tow (loose vegetable fiber, like rope that hasn't been twisted) soaked in pitch. The tow and pitch are replaceable on the reusable variety, burn fairly brightly and for a good while (roundly an hour or so); further, the flame is hot enough and distributed enough to be very resistant to wind and pretty impervious to rain of less than downpour levels.
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**Combo-hybrid-proselyte-tech.**
One of these (a hand-pressured kerosene blow-lamp):
[](https://i.stack.imgur.com/NZ3X3.png)
[Alltools.blogspot](https://alltooltips.blogspot.com/) Eugbug 2022 fair usage.
And this ([limelight.](https://www.youtube.com/watch?v=UuEr6fheqDI)):
[](https://i.stack.imgur.com/7GlY0.png)
Theresa Knott via [Wilipedia](https://en.wikipedia.org/wiki/Limelight) [Share-alike 2.5](https://creativecommons.org/licenses/by-sa/2.5/deed.en) 2022
Made with a quicklime (calcium oxide, made by heating chalk) heating target. Usually seen with a shell-shaped (scallop or cockle-shell shaped) reflector. Gives an intense bright green/white glow, reminiscent of old-time music-hall.
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I agree with the other sources here, oil lamps are probably your best bet. Something I'll point out though, is that if you have oil lamps you will probably have basic technology for electricity. Nothing like incandescent bulbs yet, but for very niche applications, like floodlights, early electric options are available.
Most notable among these are arc lamps. These were the precursor to our modern electric lights, and were relatively simple, requiring only charcoal sticks. However, they were not terribly efficient and were very bright. I'd recommend looking at this video as a great visual aid to this, as well as more info.
<https://www.youtube.com/watch?v=ThBkzEfjVl0> (reinventing the carbon light bulb)
It first originated around the beginning of the 19th century, but with some finagling in a fantasy world (or alternate history) you could perhaps have it arise earlier - it all depends on demand.
I am aware that this question was about the most advanced form of torch. I felt this answer would be useful as it relates to methods for generating light before wide adoption of electric lighting.
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So I understand a lot of world builders and aspiring fiction writers have often tried to be creative with weapons and get shutdown for various reasons of impracticality or inferiority to steel. I'm thinking why not play into that? Why not have all those weaknesses be part of a closely guarded secret known by few not unlike the Pentagon with military secrets? In fact, I'm sure there's plenty of real life military equipment specs that are closely guarded not just to avoid adversaries copying it, but to avoid having its crippling weaknesses discovered by the enemy.
So with that in mind, how feasible would it be to have an elite guard equipped with magnesium alloy swords that can be ignited into flaming sword either through specially created gauntlet or sheathes with embedded flint edges? I certainly expect it to be a terrifying sight to see.
Would its weaknesses be immediately seen by a trained fighter in combat through a simple clashing of blades? Even if so, I don't expect there be a reason for unarmed peasants to be able to tell its weakness while being singed and slashed at?
How would they most effectively employ the weapon and guard its secret? How often could they employ such a weapon?
If it is simply not an effective practical weapon, is there a way at least to use it to "bluff" the enemy to believe that it is?
EDIT:
Thanks for all the responses. Some of the comments were very enlightening to me and has been helpful in revising my idea. There's still some that I see my preface to the question didn't help steer in the direction I wanted.
For example, I don't see the fact the sword burns away as a crippling detriment, so long as it remains functionally useful and retains its form for a few minutes until the encounter is over - the enemy doesn't need to know that; this elite group may only deploy the weapon when they know the encounter will be over within a few minutes. The fact it won't survive blade contact is also not an insurmountable problem; they would use a sword style that emphasizes on dodging rather than parrying. This leaves something for protagonists to observe and eventually deduce its weakness and limitations.
As for function, well, striking fear and confusion into the enemy is already a great advantage, as is damaging and melting the enemy's equipment. They might advertise themselves as the god's chosen enforcers or some such and cleanse their enemies with divine fire when its really just science.
The fact that it would be just as dangerous if not more so to the wielder is a good point, but that need not be an insurmountable issue as the wielder can prepare themselves with proper equipment/usage as opposed to their victims.
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## How to design the sword
One thing to note about magnesium is that it is not a very strong metal. It also burns so hot and bright that setting an entire sword made of the stuff on fire is about as good of an idea as setting off a grenade in your own hand. So, rather than a sword made of magnesium, let us assume you really mean a steel sword that has been coated in enough magnesium to put on a good light show, but not so much as to harm the user. For this answer to make since, you will need to make sure the sword ignites as you are drawing it. For this, giving your scabbard a locket made of flint should cause it to spark when drawn quickly igniting the sword immediately.
## Couple it with a technique similar to iaigiri
In feudal Japan, koiguchi san sun was a set of laws designed to prevent a Samurai from drawing his weapon unless he was absolutely sure he needed to. Cliff notes of these laws were that if a samurai drew his sword more than about 9cm from its fully sheathed position in public without just cause, he could be executed for it, and once his sword was drawn, he was required to kill the person he drew his sword against before the sword could be returned to its sheath, or else he could also be executed for it... or more accurately, he would be forced to commit suicide.
These laws led to a curious technique known as iaigiri which is the technique of striking with your blade in the same action as you draw it. Since failing to kill a person once you draw your blade is a death sentence, the samurai placed a lot of emphases on training for this critical first second of a fight since letting your opponent flee was not an option.
## What does this have to do with flaming swords?
The moment you draw your sword is a unique point in a fight where your opponent is looking at or generally at your sword while it is well outside of your field of view. So when you draw your sword, there is a brief moment, where the flash of your blade catching fire as it is removed from its sheath will affect your opponent more than yourself. This blinding flash will increase your odds of landing your iaigiri cut.
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> Would its weaknesses be immediately seen by a trained fighter in combat through a simple clashing of blades?
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On the contrary, because a semi-trained fighter knows that there is about to be a bright flash of light, he will flinch in anticipation of it by closing his eyes or looking away, essentially blinding him before the magnesium even ignites. Only warriors of great discipline would be able to know they are about to face the flash of a fire sword and not break thier gaze.
On last caveat here is that if the magnesium will quickly ruin the temper of your steel effectively destroying the blade. So after the fight, you could simply break the sword against a rock preventing it from ever being returned to its sheath. So if your culture abides by koiguchi san sun law, then your warrior does not need to worry about letting an opponent live since once drawn the sword can never be sheathed or used again.
In Feudal Japan, this kind of side-stepping the law on a technicality may or may not be seen as dishonorable... but in a very similar culture, it may in fact be the whole point of your own version of koiguchi san sun law. The whole purpose of koiguchi san sun law was to prevent a samurai from drawing his sword unless it was absolutely necessary. Since swords are so expensive, making your warrior elites pay for and carry thier own 1-use fire swords would put that same pressure to keep thier swords sheathed on them without the threat of death over thier heads. So, while your version of samurai may not be required to kill or be killed every time he draws his sword, he will certainly think twice about pulling out his flaming sword over a minor disagreement if he knows it will cost him a few cows to replace.
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> how feasible would it be to have an elite guard equipped with magnesium alloy swords that can be ignited into flaming sword either through specially created gauntlet or sheathes with embedded flint edges?
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Setting a magnesium sword on fire is a terrible idea.
First lesson of chemistry lab in high school, our teacher took us into the lab, closed the curtains and put a short strip of magnesium next to a flame. The strip caught fire and lit the entire room with a bright light until it was completely burnt.
Now, while the light was bright and blinding, if that strip had been a sword, my teacher would have been left with a nice basic sword made of MgO.
Whenever you are using magnesium, you want to make sure it doesn't catch fire. Or, if you want to use magnesium in a fight, use the flame as you would use a flashbang: blind your opponent and use this to your advantage.
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**Magnesium shields.**
You want to dazzle your opponent. You do not want them to see what hits them. You are like Athena, with the head of Medusa on her shield. Pointed away from you.
[](https://i.stack.imgur.com/CRWhd.png)
Magnesium on the front of your shield can be lit and burn away over the 1 or 2 minutes while you engage your foe. You can reuse the shield with a new piece of magnesium later. You are not blinded because the shield shades you from the brilliance.
Of course if you happen to actually be Athena, you are not blinded because you are Athena.
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Why would anyone want a sword that burned up?
The old time pirates are depicted with a cutlass in one hand and a gun in another for good reason. Because the gun is one shot and hard to reload, they need the cutlass to back it up.
Making your sword magnesium and setting it on fire would make the sword as consumable as ammunition. And unlike a gun, it would gain little advantage, since the heat and the light would be more dangerous to the wielder than his foe. (He's the one right next to it.)
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> If it is simply not an effective practical weapon, is there a way at least to use it to "bluff" the enemy to believe that it is?
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You bet. Simply use a sword with a deep groove in the center, and the groove is filled with a replaceable rod of magnesium or other highly flammable compound. The sword remains a sword, but once ignited (in the case of magnesium) it's now very difficult to look at, which gives the wielder a definite advantage over their opponents. The small quantity of magnesium involved should ensure the sword remains cool enough to remain serviceable and prevent [small mishaps](https://www.oglaf.com/hot-cold-steel/).
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There are a lot of great answers already but I wanted to give my two cents, so please picture this:
You, the elite guard, twist the sword grip. One hand going clockwise the other anti-clockwise. A recessed magnesium orb placed on the sword blade is slightly raised higher than the blade level.
The next attack is a special move to strike the orb against the enemy blade, thus igniting it and blinding your foe with super bright light.
Of course that means you're blinded too, but that is why you use eyepatch or special glasses.
The next couple of seconds are all yours and all you need.
Edit: What if the mechanism to raise the magnesium orb works by rotating the pommel of your sword? Better? It could also be a button/trigger near the guard.
Edit 2: A magnesium pommel would probably be too light, but the idea of gripping your sword by the blade and striking the pommel against the ground like a matchstick and then proceding to bash your foe while using your cool medieval sunglasses is amusing. Probably would be supper effective against creatures that live underground in the dark.
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Instead of the entire blade made out of magnesium you could have grooves throughout the sword that you light, though this may be separate to your intention. This makes the sword more durable and uses less magnesium. If you want to keep the magnesium swords in full, you could equip them with another blade to block blows from enemy weapons.
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I am shooting for a futuristic image of fighter warfare (similar to the depiction in Star Wars). As jets and long-ranged targeting have developed, aerial “turn-fighting” and short-range dogfights between fighter planes have been obsolete for a while. These scenarios seem even less probable between spacecraft, given the difficulty of changing direction and sheer open space. Are there any realistic sets of conditions, on Earth, space, or an alien environment that would encourage a return to World War II-style dogfighting/maneuvering mechanics? The radar, long-ranged missiles, etc. could stay, but fighters themselves would need to be maneuverable at low speeds and engage in close-range dogfight tactics, as well as have tactical use, even if somewhat expendable. Fighters do not need to be planes (or even fly) as long as they maintain the plane-like, linear style of motion in three-dimensional space. All combatants would use the same type of vehicle.
I guess this scenario comes down to two restrictions: limiting the range of modern/futuristic firepower, and finding an environment with applicable technology to make fighters able to change direction quickly and relatively efficiently, probably by moving through a medium. Are there any general, vaguely realistic causes for this?
If this question is too broad, some specific possibilities I had in mind were that combat is restricted to tight, closed spaces (canyons, tunnels, etc.), the environment is too delicate for heavy weapons, or that advanced heat-cloaking technology or a harsh atmosphere make heat-seeking weapons obsolete. A dense atmosphere could also make planes more maneuverable. I have also considered using submarines, since this style of combat may be more realistic through a liquid medium. Would any of these scenarios realistically encourage these kinds of movement mechanics?
Side note: The future would likely see a rise in drones or automated piloting for this sort of task. While not a first priority, I would love an excuse to put pilots physically in the fighters again, in case that becomes a direct factor.
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**Why not? It's happened in the past.**
In the 50s, US air combat doctrine was that missiles were great, and guns were virtually obsolete. It's easy to see where they were coming from, on paper: longer range, much greater firepower, lower weight. But when the resulting fighters (such as the F-4 Phantom) actually got to grips with the enemy, pilots realized almost immediately that they direly needed the guns and close-in maneuver fighting that they had been told was obsolete.
Part of the problem was that early air-to-air missiles weren't a particularly mature technology and they had problems locking on at close range or, in many cases, at all. But there was also a doctrinal aspect to the problem. The US didn't want to shoot down its own craft and it *very especially* didn't want to shoot down any unaffiliated, perhaps civilian, aircraft that happened to be in the area. (A circumstance that has, tragically, occurred from time to time.)
Therefore, Air Force doctrine was to always *confirm* the identity of the target before attacking. In most cases, this meant closing to within visual range of the potential enemy, and once that distance was closed, it very rarely opened again.
Whatever it is that you're driving or piloting, and whatever you're shooting at, you're not alone in the environment. There are many non-targets sharing it with you: civilians, neutral nations, third parties, friendly forces. You need to be able to confirm that you're engaging an enemy *before* shooting - and some enemies won't make that easy on you.
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Possibly a cost-to-benefit strategy.
Capital ships, with all their power, armor and weapons are far too expensive to risk sending one in to slug it out with another capital ship.
Initially, these ships were small and not so expensive, due to the sheer difficulty of building large ships. As a result, these ships carried heavy weapons and little to no anti-aircraft defenses, as everyone had destroyers or larger in their fleets.
Over hundreds of years of development, these capital ships became colossal. Thick armor, powerful shields and devastating, large weapons. War got to a point where the first idiot got within range of the other ship would be destroyed by the equally powerful weapons of their opponent.
Then one day, someone strapped miniaturized heavy bombardment weapons to some small skiffs. All the sudden you are now approached by a swarm of mosquitoes. Since this kind of tactic hasn't really been used for 100's of years, modern warships do not have real defenses for such craft. Now, the ships' primary weapon can wipe out these fighter easy, but the targeting and recharge takes time, enough so that they cannot deal with thousands of these at a time. And if 1 of these ships got through the defensive fire, it can cause significant damage.
To combat this, rather than retrofit the whole fleet and possibly compromise the hull armor with weapon installment, the capital ships will then have thousands of small vessels, with light weapons to deter the use of these swarm attack tactics. That is, until sufficient ships are designed and built to act as screen ships.
Overall, it may cost ~$$1 billion to lose a fighter craft, but it would cost ~$100's of trillions or more to lose a capital ship. You could stand to lose thousands of fighters, which could be drones, rather than a capital ship that might have whole cities of people on board. It would be very advantageous to keep any battles far away, outside anyone's weapon range, from your fleet. Thus series of heavy bombers, fighter escorts, and interceptors may be designed to act as sacrificial pawns in a space battle. Basically, proxy battles.
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**Wrestling.**
[](https://i.stack.imgur.com/WUiDB.jpg)
It is not dogfighting. It is wrestling. You are trying to overpower the other ship because you want the ship. It is a good ship and ships are scarce. It would be a shame to blow it up. If you can get the angle right, or hit the weak spot, or grapple with it and board it, you can take it intact and then it is yours. There is no way to do that from a distance.
Robot pilots will be deactivated (and later reprogrammed) in the process of capturing the ship. Sentient pilots might be pissed off but as much at themselves as the opponent. The losers know how the game is played, and that game does not include summarily killing the opposing pilot. Pilots of captures ships will be taken prisoner, treated well and dropped off at established places according to standard procedure.
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Once the means for detecting and evading electronic countermeasures reach a critical point, visual recognition by a human can become the viable countermeasure, in a similar way to how human and computer perform better than any of them individually in chess.
Therefore, when in your scenario that point is reached and drones can evade computer only countermeasures, fighters piloted by humans can be a valuable countermeasure, because the human brain adds that pinch of unpredictability which send the AI ashtray.
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***Shotguns, Flashlights, and Lassos.***
The later ''Battlestar Galactica'' fighters used some kind of caseless ammunition in a minigun. That's great if you can target your enemy reliably. But if they're moving around a lot, you could use guns that fire in a cone, like a shotgun. Improved chance of hitting, but the further away the target, the fewer shots that make contact. If you really want to do damage, you have to get closer.
Beam weapons in sci-fi typically stay in a tight beam, which has the same problem. You could have a beam technology that, on purpose or not, spreads into a wide beam like a flashlight. Again, the power drops off drastically with distance, so you need to be close.
Finally: Since space is so big, the only way to stay near your target is to grab him with a tractor beam. Of course, he's trying to do the same to you, and there's some reason that tractor beams work best when you're behind your target. So both of you are circling, trying to get behind each other like two dogs in a fight. (Which, IIRC, is where "dogfight" comes from.)
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# Inside a Gas Giant
The density of the atmosphere prevents long range visibility and targeting. In a near-term future where solar system colonization is nearly complete, gas giants would definitely be strategic resources, as sources of fuel, places of industry etc. Industrial stations (or military ones) would likely be hidden in orbits low enough to be obscured and protected. Their orbits are jealously guarded secrets. When they're detected or found accidentally, fighters might would be a realistic method of attack, and certainly for defense. More specifically, *piloted* fighters would be useful because the atmospheric interference might prevent reliable remote drone piloting. I'm not sure about autonomous drones...
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Have large ships with sturdy structure. Those ships in battles dont get destroyed but captured.
All battles then happen at short range inside each ship. Each ship is captured in parts, plot by plot, deck by deck.
Quick maneuvering wouldnt be hard because of readily available propellant available to be thrown in other direction, and because the technology of making sturdy structure is already found in this world.
Air wars will be happening at "close quarter". Entire airports will be on the ship. Supplying propellants not remain a big deal even in an altogether space war.
Reasons for having large ships:
1. Space travel. Its long, years. It gets very boring because of monotony. Therefore each and every ship has to be large enough to have thousands of people if not hundreds of thousands living, have large areas, entire cities, lots of landscape features such as mini mountains, ponds big enough to look like sea from beach etc.
2. Space travel. Its long, years. Lots of things tend to break down. Need not just spare parts but entire components, many copies of each. Need space for all that.
3. Sea travel. In future due to over population entire small countries are just very large sea ships.
4. Economics. Its always economical to build larger structure because of square cube law, and to run it. The limitation comes in management which in this case is how much stress the ship material can handle. Once technology to build sturdy materials, lets say nano tubes is achieved construction of large ships are a given.
Reasons for having sturdy (as in nearly unbreakable) structure:
1. They are meant to last, for decades or centuries. Because space travel is just so damn long. And because sea-ships countries are obviously meant to last for long.
Reasons for striving to capture instead of destroying the ships:
1. They are very, very expensive; because they are very large and very sturdy. Better have them than destroy them. Consider conquering state of texas instead of nuking it.
2. They are hard to destruct. Therefore like a medieval fort its more realistic to capture than destroy. Medieval guns dont attempt to break down a fort in its entirety, just breach an opening. Missiles will be like canons, attempted to just breach an opening. The capturing work is done by air planes that go inside and attempt to spread soldiers around. The defense would then mostly be focused on dog-fighting those air planes. Its pretty hard to prevent a breach because attacker ships will be large too and thus have lots and lots of missiles which can be fired from many different places along the attacker ship. The attacker ships too will have sturdy structure and thus its unrealistic to attempt to destroy them.
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There are a number of ways that have caused unwanted tech not to work or not to exist:
* "Nobody knows it": The world where it happens has pre-1950s tech.
* "Impossible due to advanced magic/technology": a God/all-mighty computer/... able to influence physics itself prohibits some things. That may stop (advanced) rockets/seeker technology, or space travel, or rocket engines, or whatever.
* "Using it means death": A technology interdict exists (or honestly believed to exist), either autonomous, or controlled by a third party or by (possibly only the highest leadership) of the enemy. The enforcement might be more than powerful enough to flatten a continent ... and may have done so before.
* "Forbidden by The Federation" (a variant of "Using it means death"): While you do have all the advanced technology, you are limited to a certain tech level in economic struggle against other entities. Break that and they'll all band up and rip you apart. Also, destroying the resources & population to exploit them is bad for business. You can always come later and take over ... unless it's glowing glass. (And you may want to recruit people who are actually experts in that technology, because that is the technology their planet is at.)
* "Transported in time": You may have advanced technology but maintenance will kill it sooner or later. Or you may have been using clubs and now need to learn a new fighting technology. This new world has dogfighting.
* "For honour": Like the single combat of knights of yore, many disputes are solved by single or small-group combat, plane-to-plane, in the air. First to touch the ground loses. If both are undamaged, both are sacrificed to the now offended gods of Courageous Combat. Or it's duels, often fought by (paid) champions, to settle questions of insults and honour. Or debt.
* "It's all sports": Think Super Bowl. (Inter)national heroes. An industry making USD $trillions, bets where whole core planets pass ownership are normal. Planetwide transmissions (full virtual reality, though to look through the eyes of the pilot costs extra, so does feeling exactly what the pilot's body feels, and if you want to have the feelings and thoughts ... well, that needs the Platinum Membership), beamed over the local system and via courier to all core worlds and a good number more via flash 'jump. Those that live, get rich and famous. Those that go down in flames ... well, good thing that cloning most body parts is easy and lots of money is made. Though a hole in the head is no good news.
* "In the cyberspace": It can kill you just as easily as real life, only faster, as the thought and not the slow body. For full speed you have to remove the safety that may protect you --- without, you will be p0wned by everyone else as they react faster.
Your "environment", the one you are most comfortable with and how everything is 'described', 'displayed', 'shown', 'interpreted' in is planes dogfighting.
* "The Meeting of Worlds": There are portals that lead to other Earths. They are very similar to this Earth, for example general geography is the same --- and so resources like coal, oil, iron, copper etc etc etc. are found at the same places. There are no humans, though.
As the portals do not link to the same place --- you could end up in India from a portal that's on Manhattan Island, or near the south pole, or nearby the Aral sea ... so the first thing you want to do is find out where you are (and no GPS ...) and then find other portals to further worlds.
Now, let us assume there are other Earths that do not quite like this one, that have their own civilisations. Another civilisation may not use the same magic like we do. Where we ride (fire spitting, preferably) dragons, they might use woollen carpets carried by Sylphs. Or levitation and repulser forces for movement. Or liftwood and harvested materials, which when dried and mixed with each other, produce generous amounts of heat --- used in a small tube it can cause movement, used in a bigger, sturdier tube in larger amounts can propel an stone or iron ball at speed ...
Or [imagine](http://www.julesverne.ca/vernebooks/jules-verne_robur-the-conqueror.html) a large multi-screw [gyrodyne/heliplane](https://en.wikipedia.org/wiki/Gyrodyne) and a push-pull propulsion system (see [Robur-le-Conquérant](https://www.gutenberg.org/files/3808/3808-h/3808-h.htm)) but powered by "hamsters" in "hamster"-wheels.
Or even some magic using fast airpaddles attached to some noisily humming, stinking gnome, which wants oil sacrifices, with 2, sometimes even 3 long fabric beds (which supposedly carry it) and some small ones in the back, which can flap but are not used for propulsion, for some reason ...
Now, there is a long, long chain of Earths (and probably not just one) between any 2 civilisations. And of course, Sylphs will not work in our world, nor will liftwood, or that gnome thingie. And vice versa ... but over the chain this changes bit by bit, so bit by bit their technology works better and ours worse. So you can have almost any kind of flying thing versus flying thing, with as much down-toned technology/magic as you want.
This may also be an [XY problem](https://en.wikipedia.org/wiki/XY_problem): the question is about some dog fighting action going and how to get it --- but I think you may want to pare down the requirements, not on the technical side ("plane-like, linear style of motion in three-dimensional space" and "close-range dogfight tactics") but on the emotional side.
What is it that dogfighting offers that you want/need?
* How the pilot feels the plane, squeezed into the seat by pulling hard and nearly blacking out, the rumbling of the engine, the staccato of the MGs blazing and the basso ostinato of the canon's dry cough?
* The danger, easily seen as the weapons rip apart another plane; you fearing for your life as you notice the plane diving on your 6 too late, escaping --- almost --- and later nursing the shredded plane back towards home, hoping the engine will not give out, the oil not completely obscure your view, the leaking fuel will not catch fire and last to touchdown, the bullet in your leg missed an artery ... hopefully, or the panic of trying to escape the burning plane, the exit jammed (no ejection seat invented yet!) and the parachute being licked at by flames ...
* the majesty of flight, of soaring ... versus the instant death from flak or SAMs, the danger of an enemy sneaking up to you, obliterating you with one burst, the streams of bombers trying to flatten yet another city of your home?
* an action movie in written form (yes, I've seen that done and it worked quite well on me)
* a more technical/tactical tale of high scissors, 2 circle, overshoots, gyro-controlled reflector sights, self-extending slats, turn rates and boost pressures and roll rates?
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#### Acceleration
I think that no sci-fi movie ever gave the idea of how would a war really go on in space. The real point is that space means a lot of space, a lot of room to accelerate and reach high speeds before meeting your enemy, that would compensate for the fact that actually nobody came out with a plausible idea for an energy shield. So, the best way to attack a planet would be to let your space ship accelerate for days then point to the target, shoot as much as possible during the fly by, run away and prepare for a new attack. If the defenders wanted to chase the attacker after the fly by they could not use a big, massive space ship, it would take too long to accelerate it to the necessary speed. Only lightweight fighters could accelerate quickly enough to give them a fight.
**Let's add some spin**
Imagine a space ship made by several smaller ones connected by a frame in a circle leaving the centre empty. Some long arms extend on the sides making the circle appear much bigger, on these arms there are lights, lasers and antennas that emit waves in many frequencies making the ship very visible. But the lasers are angled and overlapping to let the image appear blurry. Should such a ship start spinning it would appear even more blurry, a camera with a very fast shutters would not help because the lasers would neutralise it. Imagine such a ship attacking, the defenders would just see a big blurred disk approaching at very high speed, if they shoot at the centre the shots would go through. Only lightweight fighters could accelerate and maneuvre at a high speed to get on the side of the attacker. And they should be so much lightweight that their range would be very short, but in space if a fighter finishes the fuel it does not fall somewhere, provided it slowed down before ending the fuel it would have just to wait for the carrier to pick it up.
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Say a group of silicon-based aliens arrive on earth, would their bodies be able to extract any nutrients from carbon-based food?
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**Silicon bodies, carbon energetics.**
from my answer here:
[How could a pathogen feed on silicon while infecting humans?](https://worldbuilding.stackexchange.com/questions/171370/how-could-a-pathogen-feed-on-silicon-while-infecting-humans/171375#171375)
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> Your opal creature uses silicon for its body, but has conventional
> carbon energetics.
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> When we eat, we use our food for two things. We metabolize some for
> energy and we use some for anabolic processes - building our bodies
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> There are creatures who split these functions. Iron oxidizing
> bacteria, for example, have bodies made of the same sorts of carbon
> molecules that we use. But for energy, they oxidize iron. They do not
> use the products of their energy metabolism for any anabolic process -
> the iron oxides are waste.
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> Your creatures use silicon to form their bodies. They are opalescent
> creatures, their bodies laid down from layers of soluble silica.
> Energetics however are much like ours - they oxidize oxidizable carbon
> and retrieve the energy.
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It is not so outre. Consider our own bodies. They contain a huge amount of calcium, as bones. Can we "calcium creatures" eat glucose? Sure! We cannot use calcium containing molecules for energy. We must obtain the calcium in our diets and then process it into bones, which costs energy to do but makes us awesomely bony.
So too your creatures. Their bodies are made in large part of silicon and silicates or siloxanes. Their energetic biochemistry is similar to Earth life, either reducing or oxidizing carbon containing molecules to release energy. That energy is then used to do silicon chemistry just as we use energy to do calcium chemistry.
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In general, as [L.Dutch wrote](https://worldbuilding.stackexchange.com/a/217929/8732), a silicon based lifeform will typically be unable to process carbon-based foods.
But since this is Worldbuilding, and you might need a different answer for your story purposes, let's look into ways to make it possible.
A hint in advance: I'm not a biologist. So I may be horribly wrong in what follows.
Our bodies, and those of any larger creature, are home to myriads of microbes, of which be benefit, as they do from us.
To the best of my knowledge, there are microbes on earth that are able to break down rocks.
On top of that, it seems that there is no (chemical) task you could think of without somebody somewhere finding microbes that already do that job. I'm probably exaggerating, but the general principle should hold.
So, your aliens are space-faring. That means they are technologically advanced, and by a lot, compared to us. They will surely know in advance what type of planets they will be visiting. It's unlikely they just stumble upon earth, Columbus-style or such. That means they will come prepared to facilitate their survival in the environments they encounter. Being technologically advanced, they may very well have bio-engineered some of their gut microbes so that those digest our carbon-based food and create silicon-based food as an end-product of their digestion, thus enabling your silicon-based aliens to benefit from carbon-based food.
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Most likely not, in the same way no life form on Earth can extract nutrients from eating silicon based compounds. The closest thing I can call out of my mind is chicken eating stones to help them break food in their stomach and to get elements for the egg shell. But that's not made of silicon.
Moreover, a silicon based life form would be adapted to process silicon based compounds, with silicon adapted enzymes or equivalents. Enzymes are so specific that we are not able to digest cellulose, though it's made from chains of glucose. Imagine how big is the jump between carbon based and silicon based molecules.
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Depends on what you mean by 'eat', and what you mean by 'life forms'. Silicon-based life could mean robots or otherwise mechanical creatures, they could take in the carbon-based items and burn it for fuel/energy. It's probably not going to be an efficient form of energy extraction unless they're built to harvest the joules that way, but it's certainly an option.
As for whether or not an actual living thing based in silicon instead of carbon eating carbon-based things, that's probably not going to work out. I don't think I've ever heard of something eating sand and getting nutrients from the sand itself. Maybe the tiny life forms in the sand but not the sand itself. I'm now envisioning a beach of carbon, the dark sand contrasting with whatever you have for oceans against the sunset, with a silicon crab seemingly eating the carbon sand only to spit it back out once it's done filtering what can sustain it out of the grains.
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# Different Nutrients:
This is implausible, since it's enzymatically unfavorable for a silicon organism to evolve enzymes to break down carbon organisms. After all, all the organic parts are immediately unusable for materials. But with a little manipulation, there could be benefits. There would also be large numbers of compounds in organics that would be poison to silicates, and the biological solvents would need to at least partly match up.
* Plants are able to trap and decay animals to extract minerals like nitrogen from the animals, despite the plants not classically "eating" the animals. this is because the animal contains something useful to the plant. So if the silicon organism wants soluble iron, or sodium, or something like that, they COULD get it this way. It would be pretty inefficient, but not impossible.
* I do agree **(+1 Burki)** that a hybrid organism (like a bacteria that is designed or evolved to use both carbon and silicon) could likely extract chemical energy and possibly some limited compounds (like ammonia) from the carbon-based food, then produce food usable by the silicon organisms. Again, this is likely to be pretty inefficient, but a species of great intelligence and limited imagination (or some other compelling reason like a genetic obsession to hunt and eat prey) could obtain at least partial nutrition from carbon-based food.
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**Vitamins**
The silicon based organisms cannot survive by eating organics but organics carry trace elements that might be energy intensive to sift out of raw rock. Thus, they often eat organics to gain a low cost source of those trace elements.
**Getting High**
Humans (and some other animals in Earth) often eat poisonous compounds to get high. Organics may be poisonous to silicon based life forms. However, in the right doses, they can cause various effects (getting a buzz, getting hammered, hallucinations) that they might enjoy. "Gerbils make me jittery but oak is groovy..."
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Actually, carbon and silicon can and do react with each other to form useful compounds, for example [Carborundum](https://en.wikipedia.org/wiki/Silicon_carbide) and [Silicones](https://en.wikipedia.org/wiki/Polydimethylsiloxane).
The former would probably be a good material for teeth (or skin scales or anything like that) and the latter could be used as analogues of blood, fatty tissue and for covering the bending parts of the limbs of your creatures.
So it could even be essential for silicon based creatures to ingest (at least some amount of) carbon or even carbohydrates.
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**Yes**, given appropriate "circumstances", it could be the case.
This subject has been "entertained" in research and, in fact, [relatively recently](https://www.nature.com/articles/nature.2016.21037). The link points to an article (official scholarly reference [here](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5243118/)), which describes how scientists managed to slightly manipulate an enzyme from an extremophile bacterium and inject it into *E. coli*, which, given the "right" precursors, can catalyse the formation of carbon-silicon bonds. This is akin to carbon fixation (formation of organic carbon compounds from inorganic carbon).
Now, look at **that**! You get both elements at once, in living cells. These can be cultured in appropriate silicon-containing growth media and used as food by your aliens. If we are going to assume your aliens are like the "humans of their own environments", it is much more likely that they will have enzymes to break down such "organosilicon" compounds and suitably utilise *that* silicon, than to have the appropriate machinery for "silicon fixation" from "raw" inorganic silicon.
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Bones can be not quite enough sometimes, and for my secret military organization, every possible advantage is given to the soldiers. Including reinforcing bones. But...where do I put the metal?
Material specifics:
* Handwavium Material X
* Will not cause blood poisoning/other effects once in place
* No ill effects during placement by nanites
* At least as strong as steel
The material will be placed while the bones are shattered, so there is easy access to anywhere in/on the bones. Once the material is in place the soldier is given some Skele-Gro to fix the bones together in about five minutes. The metal as well as calluses(which remain thanks to a slight modification in the SkeleGro) make for very strong bones. In theory.
Assuming the material can be placed easily, where do I put Material X for maximum bone reinforcement? If it uses less that's great too, but I don't think it will be very easy to measure how much your method uses without actually trying it.
Below is just a bunch of information not in the original question from the comments I'm just putting here so everything is in the same spot.
* Looking more for blunt force protection than bullet proof bones. If they can be tossed around and then get back up whereas most people would be waiting for an ambulance, that's more what I'm looking for.
* Don't worry about ligaments, just bones at the moment.
* Try to keep mostly bones rather than completely replace the bones. Keep at least a 50-50 bone-metal ratio. More bone is better.
* Doesn't necessarily have to be metal, anything that strengthens will be acceptable.
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### On the outside
Of the body that is.
It's generally a bad idea to have anything in the body that the body can't repair. The metal is going to get bent and broken, it's going to need repair. It seems you have some solid medical technology going on here, but if you need to replace the bent metal in someone's leg that's a major operation you've set yourself up for. Better to let the bones be bones and give the troops power armour.
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I read the question and the answers and this is what I believe that will help you:
Your soldiers already have a strong armor but you want to give them a strong skeleton.
Replacing a percentage of their bones have a lot of pros and cons.
Bones are already really strong, but I believe I can help you to make them stronger:
* Put the reinforcements on the outside - this way you don't need to shatter their bones and them use Skele-Gro - The calluses have their own pros and cons
* The reinforcements should be something that keeps the bones in place without prejudicing them: maybe a strong elastic net:
+ That allows blood to go in and out
+ It maintains the bones in place when something breaks them
+ The net itself can elastically repel some bullets and also is easier to repair with nanobots
+ If you really want stronger bones, the net can be used to compress the bone to make it stronger (but also easier to shatter) - maybe the compression can be electronically controlled so it changes based on the situation
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**Graphene**
There's two things you want to do. First you want to make the bones more like children's bones. They have competitively more cartilage than calcium in there, if my translation efforts serve me well. That means they are able to bend more, thus break less fast. Bones of older people are more strong in the sense that they keep their shape, but that means they are also more inflexible and thus break faster. So bones with more cartilage and thus more flexibility are preferred, especially as you get the strength from whatever you put inside it.
What you want to add is Graphene. With nano-tubing you can make incredibly strong and flexible materials. To support the bones, you can add a diamond or honeycomb lattice throughout the bone, most preferably a 3D version. The lattice can certainly be added to the surface of the bone as well as the attachment points for ligaments and such. Possibly it can near fully encase the bone as well, while still allowing . Depending on the area there can be many small shapes for strength, or some larger ones to just keep everything together. Made correctly they can soak up most of the energy of many common impacts, reducing the strain on the normal bones.
The lattice will let the bone still work as normal, so normal functioning for the immune system for example is unimpeded. Graphene is made from carbon, making a rejection reaction low as far as I can tell. Damage to the Graphene can likely be absorbed, just like most carbon in the body, while the bone can regrow if any Graphene goes missing. If ligaments or muscles lose their attachment it can still regrow to the Graphene or the bone underneath. Even if this would be problematic, it is likely that the soldiers are brought back in for a new treatment anyway.
One "negative" is that the nano-tubes are set in a certain way. The honeycomb lattice should reduce this, but especially with encasing the bones you have most of the nano-tubes set in a certain way. Even if you double-up or more, where the first layer is all horizontal, the second vertical, the third diagonal to the other two, etc., you will never have the full strength available. This is not an easy blanket strength thing. For example, the legs will be strengthened mostly for running and falling. Although the lattice and such will help, a club to the side of the leg can still easily break it, especially if the leg is standing or otherwise braced.
Further advantages of the nano-tube Graphene is that it isn't magnetic or otherwise detectable with normal means, allowing the soldiers to function in normal life/undercover.
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**This is hard**
No, really, the fact that you want to "mettalize" your bones will create a few problems.
First, as @Separatrix said, the body has a bad time reacting to things that himself can't repair or are strange to the body. The metals usually used in fractures are a mixture of stainless steel and titanium, titanium might be a better option since it's stronger and withstands some strain.
Second, bones are not completely rigid. They can strain slightly. This is important because the harder a material is, the easier it is to shatter when bending or hitting it. If for example you want to protect your soldiers from blunt force, the titanium might shatter on hit, creating internal injuries each time your soldier moves that muscle.
I would follow @Separatrix answer and add protection on the outside. But not metal. Metal was used in the medieval era to protect against stabbing and slicing, being very most useless against blunt weapons (because the impact is still felt throughout the body). Use something that can absorb the hit instead, something made of fabric. Adding the advantage that will be easier for your soldiers to move around.
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**Drag those supersoldiers into the millenium!**
Metal, schmetal. Schmetal, I tell you! What are you, patching up Steve Austin? **Carbon fiber** is how one reinforces bones these days.
[](https://i.stack.imgur.com/fmwmO.png)
<https://www.podiatrytoday.com/exploring-carbon-fiber-fixation-lower-extremity>
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> Carbon fiber technology provides strength and durability with ease of
> placement in comparison to stainless steel and titanium. The modulus
> of elasticity of the carbon fiber technology is closer to that of
> cortical bone than stainless steel or titanium implants, allowing the
> surrounding bone to function without undue stress from the internal
> fixation. The implants are composed of longitudinal and
> diagonally-oriented fibers of carbon, allowing for strength in
> multiple planes.
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That xray is a little retro with the metal nails; those can be carbon fiber too. You don't need to shatter the bones. Slip the carbon fiber rod down the middle and sheathe the outside where you need it. The carbon fiber rod can flex like bone and if the bone breaks the rod will hold the pieces in place while your supersoldier chugs some of that Skelegro you did not need to use.
Carbon fiber rods and plates in bones is not fiction.
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This is the microstructure of compact bone (cortical), this is the calcium phosphate and collagen that makes up the nonliving part of bone and this is what you are replacing.
[](https://i.stack.imgur.com/Z6832.jpg)
Your big problem, you see all those holes, those have to be there, they contain the blood and nerves that allow the spongy bone and marrow to grow. spongy bone functions to regulate your blood calcium and phosphorus.
[](https://i.stack.imgur.com/gv5l6.png)
How to replace it without loosing those blood vessels is the hard part. I know of no existing technology that will allow it. you may have to resort to a handwave like nanomachines.
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I'm creating a humanoid bird character. In essence, they are still human with the usual four limb package and upright walking. However, they have two wings on the back for flying, and the feathers, beak, etc. I have no problem with naming the anatomy things such as legs, arms, wings, face, and whatnot. Birds have feet and legs, and thus those terms are easily applicable.
But "hands," the gripping tool on an arm's end, are another matter. Birds do not have hands, so using the term "hands" to describe them does not suit me. Birds have three "fingers" in their wings. My plan is for my character to have an opposable thumb and two fingers.
Are there any known or "official" terms for such a "hand"? "Creative" alternatives are limited to only bird-related terminology and biology only, to avoid an open-ended and opinionated question.
If it is any indication, my humanoid wolf characters use the alternative "paws" for their hands.
Addendum 2/22/2021: Per @chasly's extremely helpful suggestion, here is a rough sketch of my character's anatomy. I've labeled it as well.
[](https://i.stack.imgur.com/ymTeS.jpg)
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If you want something that is specific and biologically apt, then go for Latin or Greek (ancient).
* Latin would be [Manus](https://en.wikipedia.org/wiki/Manus_(anatomy)).
"the biological term for the distal portion of the forelimb in tetrapods" (hand).
Whence we get mannerism (to do with gestures).
* Greek would be [Chiron](https://en.wiktionary.org/wiki/%CF%87%CE%B5%CE%AF%CF%81)
"From χέριον" (hand).
The Ch is not the familiar sound from "cherry", but an aspirated-K sound (Kh) which is not native to English, but usually gets verbally anglicized to just "K". So "Khy-ron". Whence we get chirality, chiral.
It's rather up-to the writer, but words which might suit are:
*"mitt"* if the fingers are joined by membranes and covered in feathers, if so, they'd resemble a mitten type glove, which allows some individual flexion, but prevents complete separation of digits (excepting an opposable thumb).
*"forelimb"* if being descriptive and non-technical.
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## Hand
The correct biological term is hand. a hand is the distal portion of a forelimb used for grasping, if the walk on it it is called a forepaw, if they use it to fly it is wing, if they use it to swim fore-flipper or just flipper if they have no hind-flipper.
You are wrong that birds do not have hands, Hoatzin have hands, other birds do not have hands but they don't have mobile fingers either.
<https://www.researchgate.net/figure/Dorsal-view-of-left-hands-of-late-embryos-of-Hoatzin-Opisthocomus-Neognathae-after_fig4_13078851>
[](https://i.stack.imgur.com/UE7Gj.jpg)
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### Claws.
If the hands of this hypothetical race are constructed similarly to how bird feet are constructed, I think referring to them as "claws" would be within the realm of reason. Bird feet are clawed and covered in scales, so calling the appendage as a whole "claws" is within English idiom, if perhaps somewhat derogatory by indicating connotations of monstrousness. It's not a scientific term, but it would work for colloquial speech.
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**Talons or fore-talons**
Some birds have feet designed to grasp prey in a manner similar to hands so they would likely generalise this vocabulary.
Talons of the feet are distinctly different things under this nomenclature, however I could see a cat-person calling their hands paws, so I don't think that's a big stumbling block, at worst you'd differentiate them by calling them hind talons and fore talons.
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**Manus** or **digits** are used in reference to pterosaurs. See [1](http://www.reptileevolution.com/pterosaur-fingers.htm) and [2](https://core.ac.uk/display/226647875)
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You could call your bird's fingers **phalanges** because that is what they are.
[](https://i.stack.imgur.com/Wa3I8.jpg)
Phalanges is not a bird specific term but a tetrapod term. Our phalanges are our fingers, each one being a phalanx and I presume for your bird too. Your bird does not have a hand because the carpals and metacarpals that make up the human hand are otherwise occupied for the bird. The bird just has the fingers.
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# chiropter
which is Greek for "hand-wing". Notably, the scientific name for bats is the [order Chiroptera](https://en.wikipedia.org/wiki/Chiroptera).
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## Disclaimer
I am not sure whether this question belongs here or in the Physics SE but I'm posting here due to the fictionnal aspect of the celestial body.
## Context
I'm writing a story where humans discover a small planet-sized celestial body they name **Eurarch**. After investigation, they discover Eurarch has a core located in one of its extremity where the density is about 2.5 times greater than anywhere else in the planet.
They manage to land and establish a colony on the opposite extremity, where the gravitationnal pull is the weakest. An expedition is sent to travel through months to the densest extremity of Eurarch and, as the gravity seems to goes stronger and stronger, they finally reach their destination.
They discover that Eurarch dense core is an artificial construct and part of it manages to expel whatever inanimate object ending up too close to the core to the other extremity of the planet, thus keeping the dense artificial core at one extremity.
## Problematic
The gravitation of Eurarch is one of the key point of my story and I would like to know if a celestial body where the gravity goes stronger as you travel toward the "core" is possible ?
If so, I'm almost sure it cannot be a globe but I cannot figure out what its shape would be ?
## Additionnal informations
* Eurarch's size is variable to fit the problem but is at least 500km long. The core size is variable.
* Eurarch's rotation is inexistant or almost inexistant
* Eurarch's shape doesn't have to be closed to spherical, it may look look like a weird ovoid or even a [Kerbal command pod](https://wiki.kerbalspaceprogram.com/images/thumb/3/35/Mk1-3CommandPod.png/190px-Mk1-3CommandPod.png) if it is has to
* Day/night cycle presence/absence is not important
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## No artificial core required
If you have a planetoid that is disc or egg shaped like [Saturn's inner moons](https://www.newscientist.com/article/2198493-the-weird-and-wonderful-inner-moons-of-saturn-revealed-by-cassini/) or [Haumea](https://en.wikipedia.org/wiki/Haumea) you get a situation where the effects of gravity are greater at the sunken in parts of the planet than the extruded parts. This is because the bulk of the mass in moved in closer to the observer.
Disc shaped planetoids typically have a spin which helps contribute to it flattening out and will have a day-night cycle. Egg shaped planets get tidally locked to the star and [generally do not have a spin](https://worldbuilding.stackexchange.com/a/87969/57832), they don't cause a day night cycle because the Y-axis aligns to the light source. Egg shaped moons will have a day-night cycle once a month as it orbits its parent planet.
[](https://i.stack.imgur.com/YVXQ2.png)
## If the artificial churning core itself is a key element of your setting
*Since this is a Clark Tech thing anyway, you will need to handwave away the heat generated by such a mechanic to have an even potentially livable planet. SEE: cmaster's answer for what happens if you don't do this.*
Because the core will be pushing matter straight down and pulling matter in around itself to keep itself up, it will cause the planet to bulge out on the far end forming an egg shape. Plate tectonics will move very fast on this world; so, the low gravity zone will be VERY volcanic and the whole world will experience continuous earthquakes. Civilizations will be constantly needing to migrate away from the core to prevent their cities from being pulled into it.
Also, gravity will not transition as smooth as you might think. Because the world will be thinner along the "sides" gravity could easily be as strong or stronger than when you get closer to the core for the same reasons I mentioned above. Moreover, gravity will be slanted towards the core. So the whole world will feel like a giant hillside sloping down towards the core. This also means that if your world has a hydrosphere that all rivers will flow towards the core side of meaning your world where it will form a what is probably your only ocean. The low gravity zone will be a dark, cold, and dry wasteland... except for all those darn volcanoes. Also, the Ocean may either be VERY deep or almost non-existent depending on just how close to the surface the core is. If it's breaching the crust, then any liquid water that forms on this world will just be sucked back into the mantle, but if the core is below the crust and if the age and composition of this world is anything like Earth. All that volcanic activity will cause the world to churn up new water much faster than the Earth does, and this ocean could easily extend up past the daylight side of the planet leaving you with no dry land with sun light to colonize.
Even without being a molten wasteland, this would not be my choice of worlds to visit, much less try to live on.
[](https://i.stack.imgur.com/0wIJe.png)
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A large body of significantly higher density would tend to sink toward the center of the planet.
A large enough cube of gold, for example, would break the rocky surface and sink toward the center of Earth (and would probably collapse under its own weight).
Moreover, a significant imbalance of the mass distribution around the axis of rotation would significantly perturb the planet rotation (ever seen footage of people throwing a brink into a spinning wash-machine?).
Since your artificial structure is so large to significantly affect the planet gravity, I think it falls in the above cases.
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### This would be possible on a very small planetoid.
A very small body can be non-spherical, or some weird shape which can have its core not in its direct centre, what "very small" is depends on [what the body is made of](https://astronomy.stackexchange.com/questions/2092/what-is-the-minimum-mass-required-so-that-objects-become-spherical-due-to-its-ow). Estimates of the upper bound for non spherical bodies are about $6\cdot10^{20}$ kg.
As the body gets larger, gravity causes the rock / ice / etc to break up and fall "down", and form a sphere centered over the center of gravity.
If your body has a small enough mass not to collapse and become spherical, but became spherical through some other means (eg aliens mined it), and that sphere doesn't line up with the center of gravity, this could exist.
Some playing around maths suggests a sphere with radius 300km, mass $6\cdot10^{20}$ kg, with the center of gravity offset by 100km, could work. Gravity on one side would be 2.5% of earth, the other side would be ~10%.
Larger sizes are possible, so long as the mass stays low enough not to collapse it. It could have hollow regions or be made of something really light. A 600-400 split would be about 1% - 2.5% gravity.
[](https://i.stack.imgur.com/Yr5jw.png)
*White marks the centre of gravity*
This could be any shape. Egg. Cube. Cigar. Tetrahedron. Anything you want. So long as the mass is small enough to not collapse it into a uniform sphere with center of gravity in the middle, it can be any shape you want.
The planetoid can't have any decent spin to it, it'd wobble.
Also anything orbiting this would figure out pretty quickly the center of gravity was off center, something trying to orbit at a height of ~190km would crash into your colony. This would've complicated settlement.
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>
> They discover that Eurarch dense core is an artificial construct and part of it manages to expel whatever inanimate object ending up too close to the core to the other extremity of the planet, thus keeping the dense artificial core at one extremity.
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### With this condition, your planet is an egg of lava.
The problem is, that your magical core is constantly creating insane amounts of energy when it lifts matter out of its own gravity well. This energy will get converted into heat as the matter sinks back towards the core. And the more fluid the planets lava becomes, the faster it flows back, and the more energy is generated by moving it back up to sustain the egg-shape of the planet.
[This question is about a very similar setting, where water is constantly teleported from the bottom of the Marianna Trench to the Sahara.](https://worldbuilding.stackexchange.com/questions/79797/what-if-a-portal-is-opened-from-the-mariana-trench-to-the-sahara-desert/79802) The conclusion is, that the energy that's created by the rather minimal teleportation is enough to turn earth's climate into one resembling Venus. Your setting is creating vastly more energy because you actually require the matter to be lifted far enough out of the gravity well that the change in the gravitational acceleration is noticeable. This requires lifting the matter on the order of 5000km, compared to which the 11km lift from the Marianna Trench to the Sahara is just a joke.
Sorry that I don't have better news for your story.
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If the gravity is so strong, it'll pull the planet into a sphere around itself. So I would say, no, the situation you describe is not possible using our theories of planetary formation.
In addition, there will not be a significant difference in the effects of the gravity on your astronauts from one end to the other. They won't feel themselves getting heavier as they approach the dense spot, the falloff for gravity is much too high for humans to feel a change in effects over a distance they could travel in months (on foot, i assume)
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The situation you describe is not a stable equilibrium, but since you are describing something that is artificially created and maintained, I think this is not a problem.
The reason it's not a stable equilibrium is that the region opposite the offset mass, the "extremity" is uphill in the gravitational potential. Material from this region will flow downhill. You can think of it as essentially a very tall mountain on the world, and mountains only have a maximum height before they sag under their own weight.
Also, as somebody noted earlier, the heavy "core" would tend to sink toward the center of the planet unless the rock below it is unusually rigid, and if the core is so dense as to alter the gravitational potential on a planet, no material exists that is rigid enough. (More accurately, since the core is apparently much denser than the rest of the planet, the planet will tend to sink to surround the core).
But these are long-term effects, and you describe a mechanism that is actively ejecting material from the high-gravity region to the low, so I think you can simply assume that this mechanism stabilizes the situation.
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I've been brainstorming this idea of America conquering the world right after [World War II](https://en.wikipedia.org/wiki/World_War_II), during the period when USA was the only nation with the atomic bomb.
I'm looking for something either scientific or political that could have accelerated the bombs development so that it could have been dropped in the European theater before being dropped on Japan.
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> America conquering the world right after WW2 during the Period when the USA was the only nation with the Atomic bomb.
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You are looking in the wrong direction, I am afraid.
The main limitation wasn't the availability of the atomic bomb (one or many), but how to deliver them on the target. The bombers used to carry them on Japan were the weak link in the chain, and Japan was a good target because at the end of the war the only defense they had against air raids was cussing at the planes.
Bombing for example the USSR with a healthy defense system was a completely different game. See [history.SE](https://history.stackexchange.com/questions/tagged/nuclear-weapons) for more info.
If you really want the USA to conquer the world under the sword of the atomic power, you need to have rockets earlier. This means that Von Braun has to be in the USA way before the war ends. Either he is kidnapped, pardon, "friendly invited" or he flees the Nazi Germany like Einstein and many more did. Then start a parallel Manhattan project for rockets.
Once you have nukes and rockets to deliver them with no effective counters on the other side, you are done.
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There were no technical obstacles to dropping it during the war in the European theater. This was discussed, and those involved in the program worried what Germany might be able to do had it retrieved a dud (not only purloining the design, but having refined nuclear material to use for their own).
However, there were no significant research or production delays that might be removed to speed this up more than a few weeks. If you are looking for those, I suggest that they'd be conceptual and social-inertial. Had those who alerted the American government done so 12 months earlier, or even 24 months, work might have started earlier (whether this translates into having a finished bomb any earlier, who can say.
You'd still run into the problem where they wouldn't want to potentially hand the bomb to Germany, and it would be even worse earlier when Germany wasn't quite so weak and might conceivably solve the defects and send the same bomb right back to the Allies. Many things might alleviate that concern/worry, but the only circumstance that would completely erase it would be if Germany was winning and to the degree that they were desperate to turn the tide.
I have no suggestions on what that would be. I've read much WWII fiction over the years (thanks Mr. Turtledove!) where Germany fared more successfully than in reality. However entertaining those might be, my personal interpretation of history was that there are no conceivable circumstances where Germany was ascendant. They had too few resources and were burning through those at rates that would make lunatics cower. Whether those resources are steel, fuel, or men... it could never happen. Any military that launches attacks as they did will alawys win at first. Those attacks were surprising and wasteful. There wasn't some brilliant strategy in play. They were the equivalent of a sucker punch thrown at the guy with his back turned... and this guy was bigger and meaner than they (and had lots of big mean friends too). Germany was destined for defeat.
Thus, no plausible reason exists to be worried about Germany winning unless they were nuked.
None of this makes it impossible, mind you. At various times, people worry too much and react unreasonably.
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I think accelerating the production is not the only viable approach. The biggest obstacle to US world domination in 1945 was probably the Soviet Union, so they would have to fight them sooner or later. How about this alternate history:
* Relations between the US/UK and the Soviets deteriorate even faster than in the real world.
* The [Teheran](https://en.wikipedia.org/wiki/Tehran_Conference) conference ends in acrimony. [Yalta](https://en.wikipedia.org/wiki/Yalta_Conference) doesn't happen because the Western leaders distrust the NKVD too much to enter their clutches. Ambassadors read speeches prepared in their respective capitals and glare at each other.
* March and April 1945: "Unfortunate incidents" as Soviet and US/UK troops meet. The Soviets want Europe at least to the Rhine and don't take "no" for an answer.
* May 1945: Soviet-held rear areas are subject to a bombardment campaign. This doesn't stop the frontline formations, and all restraint is lost. Now the Soviets want at least France, who knows where it will end?
* Operations against Japan **stop** except for a submarine blockade. All other assets are diverted to Europe.
* August 1945: One B-29 bombs Kiev, another goes to Moscow. This doesn't stop the factories behind the Ural.
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An easier answer might be to just start the Manhattan Project earlier. Historically the germ of the Manhattan Project started in late 1939 after the first nuclear fission experiments were conducted, but nuclear physicists had the first working model for nuclear weapons and had a basic understanding of the mechanism of nuclear weapons when Leó Szilárd first conceived of the nuclear chain reaction in 1933. The period between 1933 and 1939 was full of rapid advance in the field of nuclear physics- if you're rewriting history anyway, you could just compress this period of time by a year or two.
It was known that Hitler and Nazi Germany was shaping up to be an expansionist power by the end of the late 30's. In fact, Germany annexed the Sudetenland in 1938, which is what really set off alarm bells for the Allied powers. If the Manhattan Project started in late 1938, instead of late 1939, then they'd have a one-year head start versus the historic fact.
This would have made a big difference in terms of nuclear arsenal for the end of the war, and more importantly it would have made some weapons available for use in Europe prior to the fall of Berlin. The first bombs were dropped on Nagasaki and Hiroshima on August 6th and 9th of 1945- so if they were available a year earlier they'd be ready in August of 1944, just two months after the D-Day invasions. They would even be available prior to the fall of Paris in late August 1944, and then they would have been available sparingly from that point onward through the end of the war. That includes the Battle of the Bulge, as a panic response to blunt the surprise German offensive, or any point up to Germany's capitulation in May 1945.
How many bombs could have been produced after the first two? There are a lot of variables here, and nobody is quite sure of the true story. [High-level discussions around the invasion of Japan give us some figures.](http://blog.nuclearsecrecy.com/2012/04/25/weekly-document-the-third-shot-and-beyond-1945/) Historically we know that we had two bombs ready to go on August 6th and 9th, so:
* First month: two bombs
* Second month: two bombs
* Third & subsequent months: three bombs per month
If you moved the Manhattan Project schedule up by a whole year and kept that schedule, then you'd have two bombs ready in August 1944, two more in September 1944, three more in October 1944, etc.
The limiting factor in bomb production at that point is how fast fissile material could be made. We never really got to see how much fissile material the wartime Manhattan project could crank out, because the work was disrupted with the ending of the war and nuclear arms production didn't pick up again for several years after the fact. In a sense, everything up to Nagasaki and Hiroshima was just a prototype process. Depending on your story needs, you could realistically speed this up to four bombs a month, or slow it down to one bomb a month or less. The article linked above and the comments (particularly by Alex Wellerstein, who is an expert in the history of nuclear weapons) are all very high quality speculation.
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I think you have to look for some difference in the geopolitics vis-a-vis the Soviet Union. Either people with different tendencies (more anti-communist than FDR) or some sort of phenomenon where USSR had become more/earlier the enemy.
Perhaps one dynamic might be if you imagine that Hitler never invades Russia and instead, you end up with some sort of Axis of Germans, Japanese and Russians. (Italians and perhaps Spanish/Swedes/Swiss becoming Finlandized vassals of the Germans). Maybe with the US pressed harder as Hitler consolidates all of non-Soviet controlled Europe (including Britain, Swiss, etc.) and with USSR carving up China along with Japan. And the Germans taking over North Africa and the Middle East to some line in India with Japan on the other side.
Brave USA is the last holdout! Our backs to the wall, we work a lot harder than we had to in reality. And then when we open up that can of Whoop-ass, we just go for it and occupy all Axis (including Soviet) territory. No 4-way splits with de Gaulle, the Brits, and Russia. Just us.
Hmm...kind of fun to think about, actually. I would play that board game! Maybe I can create a Civ2 scenario like that.
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The biggest problem with the scenario is the United States and British Empire were reaching the limits of their resources, and the population was exhausted from the years of sacrifices and casualties.
The British actually considered something similar with [Operation Unthinkable](https://www.nationalarchives.gov.uk/education/resources/cold-war-on-file/operation-unthinkable/), but concluded that even in the strained conditions of 1945, the USSR would still could not be defeated, and that the British public would never support a continuation of the war on these terms. The Americans were coming to similar conclusions when considering different plans for the defeat of the Japanese Empire - the US Navy's proposal to simply surround the Home Islands and starve them into surrender by 1948 was rejected out of hand, and there was considerable doubt that Operation Downfall, the proposed invasion of the Home Islands would be acceptable to the American public with the projected casualty count of 250,000.
Nuclear weapons were certainly the way to break the impasse (which is why Harry S Truman authorized their use against the Japanese Empire), but even the United States, with all her resources was strained by the vast expense of both the Manhattan Project and the development of the B-29 bomber. Without the B-29, the delivery of nuclear weapons (outside of exploding them in the harbour aboard a ship).
The real issue here is that the height of America's "Imperial" impulses actually occurred prior to the Great War, with America gathering an overseas empire after the Spanish American War and securing interests in China during the Boxer rebellion. An aggressive President Theodor Roosevelt might be capable of rousing America to continue attempting the conquest of the world, but in this case, a rising America will meet the European Empires at the hight of their powers (before they were consumed in the Great War).
On the other hand, the United States may actually have accomplished your aim in the post 1945 environment without a shot. The American dollar became the world reserve currency, the Americans created and nurtured the institutions like the Bretton Woods Agreement, the IMF, the WTO and even the United Nations to bind the world into a global order of her own making.
So perhaps you need to reframe your story. Conquest doesn't necessarily need to be at the point of the sword, and America can arguably be said to have conquered the world (or a large fraction of it) between 1945 and the 1970's, and have still has enourmous influence to this day. There were a few occasions where the Americans might have actually used nuclear weapons in battle (the Korean war, the 1962 Cuban Missile Crisis and perhaps in the 1973 Yom Kippur war), but you can see in the real word this wasn't really necessary.
My advice might be to take one of these potential triggers and explore the consequences of actually using nuclear weapons then.
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[Question]
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Witches exist at all levels of society, including the top echelons. These individuals summon the orgone within themselves to perform various feats of magic through invocations. This form of magic is slow, requiring ingredients, circles, and rituals that can take minutes to hours to perform. There is, however, a quicker form of magic that focuses specifically on attack and defense. This works through a series of intricate runes that are magically imbued with orgone. An individual simply focuses their power while reciting the incantation, using their physical body as a conduits for the spell.
These runes are created through the slow process of ritual magic which are then infused to the body. Different runes provide for different abilities. Some focus on enhancing the physical (strength, speed) while others give the person unique abilities (fireball, ice freeze). They also operate differently, with some offering a certain amount of times it can be reused before being applied again (3-4 shots) and others being used within a specific time frame (5-10 minutes). Runes cannot be used together or mixed (mixing enhanced strength with fireball) because one negates the other.
A system in society developed which introduced the concept of bodyguards, who are tasked with protecting these witches throughout their lives. These guards are like samurai/geisha warriors who are raised since childhood to protect their employees. Parents often give their sons to this element, and earn money from their eventual employment. Witches power up their guards with whatever runes they seem necessary for the occasion.
The reason I invented this system was to prevent witches from being overpowered. Therefore, witches are unable to use these runes themselves, or apply them to other witches. Instead, they are responsible for ritualized magic and their bodyguards are capable of instant spells to protect and guard them. The problem is why individuals who create runes with orgone are then unable to use them even though both utilize the same source of power. For some reason, runes can only work for non-magic users.
How can this be explained?
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# Interference
The magic users channel orgone through their bodies. The runes are created by infusing them with orgone. Since you can't combine two runes, it seems natural that you can't really combine a rune with a source of orgone - magic users being a very big source.
If you put a rune on a magic user, then *at best* it fizzles out. But it might be worse if it triggers incorrectly (e.g., releasing the fireball early) or the effect gets warped (e.g., blessing of strength instead does something different).
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## Runes negate all other magic
In the question you mention that one rune negates another if both are inscribed on the same individual. This could be taken a step further, so that inscribing a rune on a magic user would negate all other magic that person can do. They can still use the rune-power as anyone else, however they would find themselves unable to summon any orgone within themselves while the rune is still active.
This would allow you to take the system in several possibly interesting directions. Applying a rune to a magic user could for example be a form of punishment or imprisonment. You could stick an enhanced vision rune on a magic user for example and be quite sure that they're (temporarily) unable to cast any sort of spell. It could allow magic users and bodyguards to spar/compete on an equal playing field.
If you would prefer a stronger deterrent, you could make the magic negation a bigger risk by giving it a chance to be permanent. Normal people don't have a risk of losing anything when a rune is applied, however magic users could potentially lose their ability to use magic permanently. Each time they apply a rune on themselves they risk losing all magic.
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**There is a reason ritual magic is slow.**
Ritual magic is slow because of the risk of explosion - if you tap magic energies all at once they can come in an uncontrollable reality warping surge. All of the rituals and ingredients are actually just reminders to take time and be gradual and disciplined. Release the magic little by little.
Runes short circuit that orderly process. In someone without intrinsic magic there is no risk. But if you are a witch, use of a rune throws the magic channels wide open. The result is dramatic and unpredictable, and may cause chain reactions that echo for decades.
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If you send Orgone out of your body during a ritual it doesnt just exit your hands or a convenient place, but will exit your body at various points.
Having a rune on your body means that during a ritual it'll sap Orgone at best, or have disastrous and lethal consequences at worst as you randomly throw some fireballs during the ritual or the rune magic is mixed into the normal Orgone causing the ritual to fail. Since a ritual might need to be performed at any time its not handy to have runes on your body. But having them on a bodyguard who can use his otherwise useless Orgone... now that is a useful way to use it.
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**Side effects**
Obviously, mixing runes and incantations must have some side effect.
What side effect happens depends on what else fits best with the story. It could be that nothing happens, or that the witch is incapacitated before (or after?) she completes the ritual, or an uncontrolled energy release, the witch simply vanishes, or reality is warped.
The society may or may not know the reasons behind that side effect.
**Too powerful**
Mixing would actually make the witch so powerful that she's more powerful than anybody.
There are multiple ways that this could happen, depending on what fits best into the story: The mere ability to vary runes during a spell may make her so flexible that she can't be beaten anymore; or there's a rune and a ritual that make it easier to create the next rune, creating an exponential power increase, or... or... or...
The downside is that the ritual takes time. And it is obvious, at a distance.
So whenever a witch tries this, all other witches will converge on her.
**It is anathema**
It is forbidden, for some reason lost to history.
The bodyguards are there not only to guard the witch, but also to prevent her from doing anything that is not within the social rules, which involve that you simply don't do both ritual and runes.
This could be done to place them under control: Establish a rule that makes them depend on others for some task, and you have limited their ability to do stuff. The restriction could be totally arbitrary, preventing them from doing something that's technically entirely within their abilities - except the bodyguards answer to the witch in all things *except* when to enforce that rule.
A society that emphasizes tradition and/or obedience would help with enforcing that: the witches are powerful, but they are bound to rules of discipline and answerability just like everybody else.
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**Runes are slow to produce and have negative effects on the body.**
Like any source of magic, the rune must have something to gain power to be able to activate or be constantly active.
The rune for the body could be considered as a radioactive chemical.
They slowly consume the vital energy of the host to be operative. After years of constant use of runes, the user begins to notice the wear caused by the runes. The damage is irreversible. Since they are samurai and can no longer serve their master, they proceed to die with honor by doing a ritual (perhaps harakiri).
As the process of preparing the rune is slow and also has negative consequences for health, the cost-benefit is not viable.
Perhaps with the past of time, somebody study the negative effect of the runes and begin to ban them.
It reminds me of alchemy theory, to get something you must give something of equal or greater value (vital energy / runic power).
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Simple: **runes channel orgone.**
A witch *could* apply a rune to herself, but she's a creature of magic, orgone flows through her body like blood does through her veins. Runes are infused to the body with *magic*, so they bind the witch's magic, making the rune permanent and diverting power from the witch's orgone reserves to power the rune's effect.
This would prevent witches from using runes for many reasons:
1. Resource Depletion-The Witch *always* has less orgone to use for magic, since the rune is always taking some. If witches die upon completely depleting their orgone, runes are also a potentially dangerous drain on their orgone. There is an exception though (see below).
2. Interference-Using your rune examples, it's clear that you have passive (constantly running, like strength enhancement) and active (must be activated to have an effect, like the fireball and freeze runes) runes.
Passive runes not only deplete resources, but eventually get annoying: imagine having superstrength all the time, and I'm sure you'll see what I mean. With that on all the time, witches would break things all too often, and find it very difficult to perform fine manipulation of objects. It'd be like becoming a gorilla for us; sure, you're stronger, but you'd also have less motor control. The same would apply to enhanced vision, smell, touch and so forth.
Active runes are the exception mentioned in Point 1: they only expend orgone when activated, but guess what? They activate *every time* the witch tries to use magic. This is *horrible* for witches, because not only does that make spells more expensive to cast, but it adds a rune-specific effect. For example, if a witch was trying to cast Freeze Solid and had a Rune of Fireball, the result would be an angry, soaked opponent.
3. Runes Ruin Stealth-As creatures of magic, witchs can sense most magic around them, as long as they have proper training. Witches know how to cloak *themselves*, but they *can't* cloak any runes they have. Additionally, runes connect a witch to magic in a way that leads to an unwanted side effects (Ex: a Rune of Fireball attracts fire elementals).
4. Runes Are An Unwanted Weakness-Going off the example above, a fire elemental can use a Rune of Fireball to draw orgone out of a witch, consuming her mana and when it's gone, her entire *being*. Besides that, a witch can disassemble a rune on another witch, but when she does so, she absorbs both the power that's gone into the rune's construction but all the power that's ever gone into it, skyrocketing her orgone capacity and leaving her victim weak and vulnerable to her power (ie. prime target for domination and enthralling spells).
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This pure-blood vampiric race is not immortal, but their lifespans *are* about five times that of mortals. This race has lived in a vast city beneath a small mountain range for thousands of years (the world outside is populated by humans) Living with them, though apart in a specific section of the city, is a colony of humans whose purpose is to act as sustenance for the vampiric race. These vampires cannot imbibe anything other than blood.
Though their city is vast, it is still a finite space and the antagonist of my story will eventually use this as a point of argument to back up his belief that they should spread from the mountain and take over human lands. He’s not going to win this argument, but I can’t help but acknowledge that he has a good point, so I had a thought that maybe the female pure-bloods usually only have one child during their lifetimes; two is not unheard of, but is extremely rare and usually kills the mother. I’d like to have a well thought out reason for this, don’t really want to just hand wave it, so can anyone lead me in the right direction? Many thanks, in advance.
In addition, though, there are a rare few *newborn* vampires mixed in with population, my focus for this question isn’t really on them. My focus is the pure-bloods, descendants of several generations. The newborns are notably different from the pure-bloods, they crave blood after being turned, but do not experience the true pain of thirst that *blooded* and *pure bloods* do until after their first drop of blood. Also, before their first drop of blood, these newborns *can* sustain themselves on human food and drink, though only very small amounts of the former, but after, their bodies immediately reject it. I was thinking that perhaps I would make the newborns’ birthrates higher, so maybe the low birthrate of the pure-bloods has to do with how long they’ve sustained themselves on blood?
**Update**
Also, female newborns would give birth to pure-bloods if their partner was also a vampire.
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Blood, by its very nature, is an oxidant. As such, it's the exact opposite of an anti-oxidant. This may sound obvious, but thinking through the implications a little deeper makes one realise that there are some serious differences to nutrition going on in a vampire's physiology by comparison to a normal human.
In point of fact, this is a paradox in how vampires and their physiologies work; on the one hand you have creatures with incredible recuperative and healing powers, which implies over-oxidisation and a higher metabolism, but then they live extended life spans, which implies under-oxidisation and a lower metabolism. For the purposes of this question however it is important to note that anti-oxidants are supposed to remove free-radicals from the body, reducing the amount of damage done to it by left over oxygen artefacts generated by normal metabolic processes.
It was thought for some time that anti-oxidants actually improved fertility in women and increased their chances of bringing live babies to term, but recent scientific studies have largely discredited this. But, it's important to note that these scientific studies focused on normal women with normal metabolisms; there were no female vampires with their unique metabolic processes introduced into the studies that have been done on the subject.
As such, we really don't know what drinking blood as a sole source of energy and nutrition is going to do to a female vampire in terms of her fertility or ability to bring a baby to term, but here is a bit of supposition for you;
For one thing, vampires are likely to have an excess of free-radicals in their system because their source of nutrition is designed from the ground up to bind oxygen to itself. As such, without a nutritional source of anti-oxidants to clean up the excess free radicals generated by the metabolism, these are likely to do a lot of damage to the body over time and may well be the reason why your vampires are not eternal.
Secondly, to live as long as they do, vampires, particularly given the existing issue of no anti-oxidants in their diet, may well have a lowered metabolism. This would explain their ability to survive on only small amounts of blood, and their extended lifespan, but would be contrary to their abilities of super speed or accelerated healing. Let's assume for now however that our vampires have a large number of free-radicals in their system AND a lowered metabolism.
The practical upshot of this is that even if vampire fertility was similar to that of humans, the capacity of the body to bring a baby to term is diminished. At best, vampire gestation rates would increase by the same factor as lifespan (say x5, or nearly 4 years) but likely even longer, and the free-radicals mean there's even more chance of random damage to the body in such a way that something can go wrong with the pregnancy. The birth itself would also be precarious, because the amount of energy required to deliver the baby would be massive by comparison to the amount of energy that the mother has available to her for the process. There would be no margin for error.
Vampires with lower metabolisms are essentially working with bodies designed for marathons, whereas delivering a baby requires a sprint; a relatively short, sharp, but massive expenditure of energy to safely bring the baby into the world.
Now, sure; we're already working with dichotomies like accelerated healing and it's possible that the body can switch between these two modes almost at will; increasing metabolism (and thirst) under times when it needs to heal at an accelerated rate and then ratcheting back down once the healing is done. Same would go for the delivery of the baby, but in my view each of these transitions between metabolic rates would incur a cost, meaning that warrior vampires, as well as female pregnant ones, only have so many times they can make that transition and so bringing more than a single baby to term requires an extraordinary constitution, access to additional blood supplies, luck, and probably all three.
Put simply, your female vampires run cool most of the time, need to run hot when bringing a baby to term, and switching between the two carries both a price and a risk that will eventually kill the mother, and probably the baby.
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Well let's be perfectly honest here and say that what determines the birth rate of any species is so deep into our genome that we are not even certain in real life. If you just say, "Female vampires can only give birth once every 5 years," no biologist on earth will question that. Unless your story is taking place in a genomics laboratory, you're never going to be asked to prove anything about birth rate to the audience. So go ahead and hand-wave it. Literally everyone else does, even real biologists.
OK, but I should add.. the "evolutionary adaptation" explanation you might want to use is very simply because, they *sleep all day* and have a *really poor* calcium intake.
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Tim's answer was great, but there's just one small thing I'd like to add to that.
In the world we know, it seems in a great many cases that predators and creatures good at evading predators have fewer children the further up the food chain we go. With what little I know of vampires, they're at the top, possibly with some other fantasy critters to go with them. Add that to Tim's genius answer, and you have an even smaller number of newborns.
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There is one point here that is pretty problematic.
1 Child per vampire couple, from a species perspective, is ultimately suicidal. From that perspective you are pretty much halving the population every generation since the one child is all there is to replace 2 adults down the road. That does not make any sense at all from a purely biological standpoint.
Taking care of that is fairly easy though. Say, for example, that it takes 20 years for the female vampire body to become fertile again. You can explain this in a whole host of ways, it doesn't really matter. Maybe the pregnancy is very tough on the female vamp and it takes that long for everything to heal. Then you add an additional condition. By the time the female has gotten to her third fertility window, she is also very close to menopause. That's where you get a third pregnancy being very risky. This could allow for a population that might very nearly become stable, as the next generation can replace the previous. It's very close to a precipitous balance that way. Lose a few females in a war situation and the population would be very slow to recover.
You guy's case for the purebloods to expand in to the outside world could be easily thwarted by the fact that the existing population is just barely maintaining equilibrium. It would not be expanding, creating high population pressure.
In addition, the Vamps would pretty much be Apex Predators, and will have to exist in an equilibrium with the prey species. If the human population is growing, the Vamp population will grow along with it, within the bounds of whatever fertility limits you put on them. If you get too many vamps, the prey species will whither. This could explain why there is a stigma against turned vampires. Turned vampires are competing for the food source.
Anyway, just things to think about.
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Here is a completely different approach. What is it about the bite of a vampire that turns a non vampire? Let us imagine that there is a chemical generated in their fangs that deposits a retrovirus into the blood stream of the victim, transforming their genome and reforming their body.
So what would happen if a vampire bit another vampire? Were that retrovirus to deposit into the blood of the victim vampire, coming as it does with a slightly different DNA or RNA sequence it might also inject into the genome of the victim vampire, but doing so on top of the changes that already made him/her a vampire, overwhelming the genome, and the normal process of transforming the victim into a vampire would be deadly were he/she already a vampire.
Now how does this relate to children? Imagine a female vampire breast feeding her infant. Neonatal vampire milk would have to constitute mainly blood products to sustain the pure blood child. And since this was the case it would be extremely hard to give the baby vampire nutrition in any other way.
Initially, he would have no teeth, but the fangs would quickly grow, and so if she was not EXTREMELY careful she would be in danger of her child biting her and injecting her with the toxic retrovirus.
Consequently, for a female vampire, every time she nursed her child she would be putting her life at serious risk. Her natural maternal instincts would drive her to take the risk, as human females have for millennia, however, the much higher risk of death would severely deplete the rate of childbearing.
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Well the answer to why species have certain birth rates is very complicated for real species.
One answer why the birthrate would be low is because of energy loss to metabolism in ecosystems.
There is a loss of energy at every stage of the trophic level ("food chain" level) approximately 10% of the energy remains at each stage. Essentially this is why there are so few big animals in the wild. There is only so much grass or other plant material in a given ecosystem. Then the herbivores (primary consumers) eat that and there can only be so many herbivores per ecosystem or the grass would run out and there would be a kill off. Then the secondary consumers eat the herbivores and there is only 10% of 10% of the original energy left. Tertiary consumers eat secondary consumers and they only get ~10% of 10% of 10% of the original energy input (sun energy usually). For this reason Quaternary consumers basically don't exist. A Quaternary consumer would have to be something that would eat an animal that eats animals that eats herbivores which eat grass (an example would be an animal that only eats lions or eagles or another tertiary consumer. How would it survive? In a given ecosystem there may be 100 lions and if this animal ate 1 a day or even a few days and the lions only gave birth once a year it would not be sustainable) there are good diagrams that explain this if you google trophic levels.
So the lesson here is that long lifespans and low birthrates are the only way that Vampires could have possibly existed.
All species given enough time get tuned to their environment by evolution and natural selection or they are exterminated. Vampires would have evolved alongside humans as humans were required to survive. If at any point they over consumed all vampires would die. Instead they would have evolved to be tuned according to the rates of humans being born and consumed.
There are, in your case, the emergent property of social species which can affect birth rates though societal norms which is a whole different can of worms.
there are many many other reasons that it would have to be that way but I think those would eliminate most concerns.
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I'm designing the type of ships an amphibious race could use for long distance travel, like a floating house, following oceanic currents. I imagine it shaped like an iceberg, with more structure below the water than above.
Essentially a big ship made of sculpted pumice. But I saw in various places that it cannot be done.
Why? What could make a ship made of pumice seaworthy?
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> But I saw in various places that it cannot be done.
>
>
> Why?
>
>
>
There are two main issues for carving a boat out of pumice:
1. Mechanical properties: a boat hull has to withstand loads without breaking, pumice alone is a glassy material, rather brittle. You don't want your boat to crack in two after taking a wave.
2. Water permeability: pumice is not water-tight, meaning that some water will reach into the hull, leading to the sinking of the boat.
>
> What could make a ship made of pumice seaworthy?
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1. Use some other material to add structural robustness: wood, steel, concrete, as long as the pumice provides just the shell.
2. Make the pumice water-tight. Apply a glassy enamel on the outer surface, for example.
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>
> Pumice is composed of highly microvesicular glass pyroclastic with
> very thin, translucent bubble walls of extrusive igneous rock...It
> forms when volcanic gases exsolving from viscous magma form bubbles
> that remain within the viscous magma as it cools to glass...Pumice has
> an average porosity of 90%, and initially floats on water.
>
>
> ...When larger amounts of gas are present, the result is a
> finer-grained variety of pumice known as pumicite. Pumice is
> considered a glass because it has no crystal structure. Pumice varies
> in density according to the thickness of the solid material between
> the bubbles; many samples float in water.
>
>
> *After the explosion of
> Krakatoa, rafts of pumice drifted through the Indian Ocean for up to
> 20 years, with tree trunks floating among them. In fact, pumice rafts
> disperse and support several marine species. In 1979, 1984 and 2006,
> underwater volcanic eruptions near Tonga created large pumice rafts,
> some as large as 30 kilometers (19 mi) that floated hundreds of
> kilometres to Fiji.* ([ref](https://en.wikipedia.org/wiki/Pumice))
>
>
>
**It seems you can make [rafts of pumice](https://en.wikipedia.org/wiki/Pumice_raft).**
[](https://i.stack.imgur.com/iHPWm.png)([ref](https://www.cntraveler.com/stories/2012-09-17/havre-pumice-raft-south-pacific-maphead-ken-jennings))
>
> Featherock pumice is made of volcanic glass. It has been sitting at
> the original site of its eruption for thousands of years. It will not
> deteriorate over time outside...Pumice is a very soft rock that will
> carve very easily with regular metal tools. ([ref](http://www.featherock.com/about-us/pumice-faq/))
>
>
>
**You can also sculpt pumice easily and it won't fall part when exposed to the elements.**
>
> There’s nothing new about pumice concrete. The Romans were using it
> 2000 years ago. Roman engineers and builders have been celebrated for
> their enduring wonders—especially for the most well-preserved of all
> Roman architecture, the Pantheon of Rome. The dome itself is a
> world-class wonder. It was expertly cast using a concrete consisting
> of hydrated lime cement, fine-grained pumice pozzolan (critical!) and
> lightweight pumice aggregate.
>
>
> Modern scientists have determined that the manageable weight of the
> Pantheon’s huge, unreinforced concrete dome is attributed to
> lightweight pumice aggregate, while the secret to Pantheon’s (and
> other Roman structures) longevity is pozzolan: fine-grained pumice
> (known as pozzolana to the Romans). ([ref](https://hesspumice.com/pumice-pages/pumice-uses/pumice-concrete.html))
>
>
>
**Pumice is also fairly durable, at least when mixed with some other materials.**
---
## But can you make a boat out of pumice?
Well, you can make a [small boat out of concrete](https://www.popsci.com/diy/article/2013-09/concrete-canoe).
You can even make [large boats out of concrete](http://www.unmuseum.org/concrete.htm).
[](https://i.stack.imgur.com/GaEox.png)
**So, sure, it sounds like a pumice boat would float.**
You might want certain parts to be poured concrete made in part from pumice stone, rather than just carved pumice. Not only will be be easier to get the shapes you want, but it will hold different pieces of pumice together and it will make a smoother surface, something your amphibians will appreciate.
[Answer]
Perhaps take the idea from Christopher's answer and use the pumice as a component in concrete. A trick people use to make concrete canoes is to use hollow glass micro-beads as one of the components. So in your world perhaps you can crunch up your pumice into very small pieces, coat the little pieces with with a resin, or use some sort of surfactant to keep the density light while the mixture hardens and then end up with a very light concrete to make your boat. That would be a little different than the Roman concrete that used volcanic materials, and probably lighter.
[Answer]
**You need something to bind the pumice together and seal its pores**
Pumice doesn't exist in large boat-sized chunks that you can carve into a boat. It's made of smaller pieces of unreliable composition. You need a resin, or a binder like used for concrete, to stick it all together. Then you build a mold to shape the thing, fill the mold, and let it set. You could instead try making planks out of the bound pumice, but that would result in a weaker boat.
Also, pumice is swiss-cheesed with holes. Water must be kept out, which is accomplished by the resin. Careful - fill too much of the internal pores with heavier-than-water resin and abruptly you have something which doesn't float anymore.
At this point, you're using a tremendous volume of not-very-strong material as the outer walls of your boat. Pumice is fragile, and anyone could step a foot through or drop a hammer through it.
The fundamental problem with the idea of a pumice boat is that the floating ability of the raw material is not as important as the airspace in the middle of the boat.
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[Question]
[
Related to [On a Speedster's perception of time and ability to function in civilian life](https://worldbuilding.stackexchange.com/questions/112390/on-a-speedsters-perception-of-time-and-ability-to-function-in-civilian-life][1])
So I have a character that is always fast, a Speedster really, 1 second is 24 hours to her. As pointed out by multiple commenters, the character is moving so fast that she's essentially a ghost, and that she's be unable to have a civilian life. This lead to a different question. With everything moving so slow, she's essentially living a world of populated by statues. With a negligible ability to communicate with people, how would she try to communicate with people?
[Answer]
I'm thinking in the equivalent of the simultaneous exhibitions in chess/go, or if you want of a massively parallel penpal experience: **she writes notes to (and reads answers from) many people at once**. By doing this, she is able to hold a few tens of thousands of individual conversations at any given time.
This would give her the potential to be an extraordinary facilitator in consensus-based decision making, being able to gather in "*real time*" (for everyone else) opinions, ideas, facts and feelings, digest them and pass them on for a ginormous crowd. Or, depending on her ethical/social views, she could manipulate a society in crazy ways.
I'm assuming the statement in the previous question "*I'm handwaving majority of physics and biology in relationship to the actual movement, and focusing on a more psychological angle.*" is still valid here. Still, let me briefly address worries about paper catching fire or being destroyed by friction. About combustion: it's not that hard to create a (locally) oxygen-depleted atmosphere if need be (e.g. burning a candle or matches to saturate the bottom of a bowl with CO2). About friction: graphite is industrially used as a *dry lubricant*, so I think it is credible that ultra-high-speed writing with pencils made of pure graphite (as in the old days) on appropriate surfaces will be non-destructive.
[Answer]
She writes a book.
She is, for all purposes, too fast to talk in any way. The shortest written messages take a few seconds to even make sense to us, and that's days to her.
So she writes a book, and emails someone whom she trusts can print it. If people take as little as a whole day to read it, to her it will look like two hundred and thirty-six years have elapsed. She will die of old age within a few of our hours anyway, which is too short a time to bond with anyone... Might as well think hard about some of humanity's biggest problems (are we grandchildren of mother nature's mother? Did dinosaur have penises? Why does Michael J. Fox have no Elvis in him?) and pen them down.
But she will do it in braille because, as explained in my answer in the previous, linked question, she can't see anything.
[Answer]
Ok so if your speedster tried to write, the pen/pencil will burn through the page with friction and emailing will be too slow with many broken keyboards.
Your speedster needs to figure out simple direct messages she wants to send to humanity. Best way to make sure she is heard is to carve her message into the ground.
Get a running start, then have your speedster stop by digging her feet into the ground. Write a message all of earth can see. Imagine like a crop circle message but inscribed into the earth.
She could change the message daily. Instruct people on how to live. Some people might even think it is a message from god.
[Answer]
Larry niven came up with an interesting idea for dealing with aliens that live at different timeframe references. They communicate via E-mail and digital media, you can read and answer at your own speed. Your speedster might need to build a custom rig (shes got the time)and type slowly but it should be possible. Electronics can be built for extremely high speed interface.
[Answer]
**Like waiting for a letter from a sailor at sea in the old days.**
**But an alternative may be possible ...**
Your speedster can employ any means to communicate which is written - i.e. does not depend on the ability to communicate using any frequency based system like talking.
Let's pick email.
Now I take between a few minutes and a day to reply to most emails depending on what they say and urgency.
Your speedster replies, from the point of view of ordinary time, in the blink of an eye, so that's no problem.
But you speedster must wait a very long time for replies to her emails.
Every minute it takes to reply in the real world equates to 60 days (two months !) in the Speedster's world.
So your speedster sends an email and a minimum of two months later gets a reply. But it's entirely outside your speedster's control how long it could take. If a reply took an hour in the real world your speedster has seen the equivalent of nearly four years (!) so by. If they took a day to reply, your speedster sees the equivalent of 94 years pass - and in all probability your speedster died waiting for a reply.
From your speedster's point of view communicating with the ordinary world would be like a person on land waiting for a letter from a sailor in the days before radio and telegraph. A letter might come, it might not. It would be months between letters or even years.
**The Alternative ...**
Your Speedsters can't get much from communicating with statues like humans. But consider a world where AI's exist and are able to communicate and think much faster than humans.
They'd be a natural for your speedster to communicate with.
Note a typical display can refresh at speeds no faster than about 200 Hz (200 times a second). So the shortest period an AI would be able to send a new message to your speedster would be the equivalent of about 7 minutes to your speedster. A more conventional 60 Hz display would bring that up to about 25 minutes between messages.
Note this also works the same way for your speedster trying to e.g. learn something from an internet page. It takes *at least* a second to refresh a typical page including time to fetch it, so your speedster has to wait an entire day (from her point of view) to read the next page. Difficult to learn with that problem.
Turning paper would be just as problematic as turning it too fast would shred it, or worse, so your speedster would need to be very patient.
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If 1 second is 24 hours, speed up factor is 86,400 - physics will instantly kill her:
* **She can't move**. If she were to walk (at 5kph typical, subjective speed) she would be instantly incinerated, because her actual speed would be over 400,000kph. Meteors of solid rock vaporize in the upper atmosphere at small fractions of this speed. Basically any attempt at moving will kill her, so she can't get to food or water. Other factors notwithstanding, **she would die of thirst in about 3 days subjective or about 3 seconds real time**.
* **She can't breathe**. Her metabolism requires her to take about 15 breaths per minute at velocity 1m/s subjective, or about 20,000 breaths/second at 300,000kph real time. This is way beyond hypersonic - it's insane. Due to friction and fluid dynamics, to her air would have the viscosity of cold treacle. Other factors notwithstanding, **she would die of suffocation within about 3 minutes subjective time, or about 2 milliseconds real time**
* **She can't live**. Never mind breathing, her blood couldn't move any faster through her circulatory system than ours. Due to fluid dynamics and turbulent flow friction, her heart wouldn't be able to pump blood at the required velocities needed to keep her conscious. **She would pass out within about 5 seconds subjective time or about 50 microseconds real time**.
The idea of her communicating, or doing anything at all actually, is a non-starter.
[Answer]
Let's start by hand-waving all the physics problems like friction, momentum, etc. We can use a made-up term that is totally original and not inspired by other fictional speedsters.
VelocityStrength or something along those lines.
So assuming that VS takes care of all the (billions) little problems that come from such a speedster, like breaking keyboards, running out of air and completely destroying everything around from extreme air pressure changes, now our speedster, let's call him Barney Warren, has several things to take care of.
Since the mechanics of this speedster as a baby are ridiculous, and you didn't specify if the power is natural or obtained later, I will only take into account adult life. I will aslo assume that this speedster ages in real time, and not in subjective time, because otherwise they'd die of old age within hours.
Time factor: 1 subjective hour = 86400 real hours
Until Barney succeeds at communication, nobody knows he exists. Unless he is willing to stand still for days (one day = one second), nobody will ever see him. Any sound he makes would be far too high-pitched to be heard by humans or animals, and any physical contact would either instantly destroy the target, or be protected by VS and do basically nothing.
The speedster then needs to change something in the environment to communicate. Writing messages is obvious, whether it is on paper, in the sand, by email, etc.
But if he wants the communication to be two-sided, he needs to be incredibly patient. What is the most likely to happen, provided this speedster is a good guy, is that he will steal a lot, but people will like it. If he is a villain, we'd all be conquered or killed within a day.
Just like everyone else, he has needs. As for food and water, his needs are probably roughyl equal to 86400 people for the same timespan. That's a LOT of ressources, and he has to obtain them without people's consent, because he'd die of hunger before anyone could say yes (at least until he establishes a decent rotation, like ask 100 000 people and pay them, then come back to the first to collect after he gave consent, etc)
I think the most logical course of action is to go do jobs hat are time sensitive, and steal the pay (while leaving a written explanation). Barney finds some place where people are doing physical work. He then uses his near-infinite time to figure out how much the owners are paying, calculates the total (hourly pay \* number of workers \* time to completion), then does the entire thing instantly (from our perspective) and steals this precise amount of money. While technically illegal, I'm pretty sure paying the same amount to get the work done instantly instead of over months would leave many owners very happy.
Then he can "buy" things the same way. Steal what you need, figure out the price, leave the correct aount of money with a post-it on it explaining exactly what you did. Some people literally do the same in gas stations if the clerk is busy and they are in a hurry, but in seconds instead of milliseconds.
Considering the incredibly rate at which Barney would do those operations, pretty much everyone would be aware of him instantly. After a very short time, some people would start making official offers to him (X amount of money/food/etc if you come do this for me), which would take into account the incredibly fast work, and would probably pay more.
Not everyone would like it. Barney would be "stealing" many more jobs than any illegal alien ever did. But I assume that by catching bad guys or saving lives every now and then, Barney could keep a relatively nice reputation and be liked overall.
As for personal connexions, it's just impossible. Long distance relationships have a much lower rate of success because distance, and delay in communications, are a huge burden on relationships. Imagine a guy who would have to wait months at a time even for the simplest answer to a question?
I'm sorry to say, Barney will never be friends with Risco and Katelyn.
As for my personal opinion, while he might not turn into a total villain, he will definitely not stay that nice for long. Nobody can stop, threaten or even lecture him. Sooner or later, he will start to work less and/or take more, and at some point will straight up just take. Nobody is holding him accountable anyway, and physical work will get boring/tiring extremely fast, especially alone. Keep in mind that while the work is done within minutes, Barney had to do maybe months or years of work, on what probably looks like a normal person's Schedule (8-12hours a day), without any help, teamwork or person bringing refrreshments. And as opposed to us, he can't look forward to being done after a quick 45 years.
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[Question]
[
Imagine there is a community of highly intelligent, well-educated and mentally healthy people. One of its core, undisputed values is that some people are truly human and some others - just two-legged animals, who don't have any real human rights.
How can that belief form and sustain itself among sane people? Are there any other, better explanations other than the one below?
1. Starting point: A world with technology level not lower than our current one.
2. For some reason (e. g. one of the regional conflicts escalates into a major war) a significant portion of world's nuclear bombs is activated. For example, the US drops nukes on Russia, which activates its "guaranteed retaliation" system and makes Russian missiles launch and deliver bombs to the US automatically (even after everyone is dead).
3. This exchange of nuclear strikes a) kills a large portion of the Earth's population and b) disrupts the DNA of all those, who survived, but were unprotected from radiation during the attack. The survivors and their children turn into animal-like, but human-looking creatures with limited intellectual abilities.
4. The only people, who survived the attack and were not exposed to the brain-damaging radiation, are the military personnel in protected areas (like officers sitting in the protected NORAD facilities).
5. Let's assume they are well-meaning and decide to re-build the civilization as we know it (preserve whatever is left of technology and cultural artifacts, make sure that the population of healty people increases).
6. Let's further assume that if a healthy person interacts with a person exposed to radiation, their child will be animal-like.
7. The goal of the healthy survivors is to gradually increase the number of healthy people. Therefore they forbid marriages between healthy and radiation-exposed people. They also invent other rules with the goal of protecting the small population of healthy survivors from the larger population of the people with damaged DNA.
8. These rules are passed from generation to generation over decades/centuries. The healthy population lives in conditions as close to civilized as possible, while the radiation-exposed people go through all stages of evolution (from monkeys to homo sapiens) and their society structure evolves accordingly.
9. After some time two things happen: 1) The effect of radiation subsides, i. e. the formerly animal-like people (those with damaged DNA) become human again. 2) The healthy survivor elite forgets the purpose, for which the discriminating rules were originally developed. As a result, it continues to treat the other group as animals (and is convinced that it's the right thing to do) despite the fact that now both groups consist of same types of people.
**Update 1: How to tell healthy people apart from unhealthy ones?**
Unhealthy people can be identified by at least two parameters:
1. By appearance. An unhealthy person has unusual physical features - fur all over the body (like a monkey), too big/too small arms and all other kinds of deformities caused by exposure to radiation.
2. By different psychological reactions. An unhealthy person may get more easily depressed than a normal one (for example).
So, if a person from the "elite" meets a healthy descendant of unhealthy parents, and the latter doesn't have any deformities nor abnormal behaviors, the former can assume that he or she is healthy.
**Update 2:**
In addition to the already presented answers, here's another scenario on how a person can develop discriminatory mindset: Imagine someone, who is treated badly by the environment and can't fight back. It may be easier for her to imagine that her opponents are not humans, but lower creatures. Discrimination (equating offenders with animals) can help cope with the emotional pain.
If a person says something bad to you, you may get upset. But if a dog barks at you, you won't. You just can't feel hurt emotionally by dogs, cats, worms and other lower-level creatures.
**Examples of intelligent people acting racist**
Some of the commenters said that if group A discriminates group B, then A is just a bunch of bad, racist people. I agree that they are bad and any serious analysis must answer (or attempt to answer) the question *How did they racism start?*. Saying *X is just a racist a...e* is equivalent to saying *Car Y drives because of the automotive energy*. Both statements do not help understand causes (of racism and what makes a car move) and do not help prevent it (which is the ultimate purpose of writing stories involving racism).
To make the statement about the car useful, the wrong concept of *automotive energy* needs to be broken down into right ones, i. e. phenomena that actually exist in reality (like electric, kinetic and other forms of energy, which are involved in car movement).
There was also at least one statement that if a person is racist, he or she cannot be highly intelligent, well-educated and mentally healthy. I don't agree with that because there are examples in history, when such people were acting and/or talking racist:
1. [John Locke](http://en.wikipedia.org/wiki/John_Locke), the great British intellectual, invested into slave trade (see section *Constitution of Carolina* in the Wikipedia article).
2. The Nazis.
3. Margaret Thatcher.
Let's look at the latter two examples in more detail.
**The Nazis**
The cornerstone of the Nazi ideology was that certain peoples (including Jews, the Slavs, Roma and Sinti) were subhumans. Some of the Nazis developed
* most advanced [rocket](http://en.wikipedia.org/wiki/V-2_rocket) of their time (on which both Soviet and American first rocket designs were based),
* first [jet fighter](http://en.wikipedia.org/wiki/Messerschmitt_Me_262) and
* a cult, which even 70 years after is so appealing to some people (including Nazis victims) that governments need to prohibit it (Hitler's *Mein Kampf* is officially [banned](http://en.wikipedia.org/wiki/List_of_books_banned_by_governments) in Russia, Germany and Austria, probably for a reason).
All of these things could only be achieved by intelligent people. The scientists/engineers behind them probably knew about the implications of the Nazi ideology (unnecessary suffering of beings, who were humans like them), but decided to support it nonetheless.
**Margaret Thatcher**
I heard from several [sources](http://en.interaffairs.ru/editors/446-weeding-out-humans-seems-to-be-an-impending-plan.html) that Margaret Thatcher said in the mid-1980es that the number of Russians should be reduced from approx. 140 million to 14-15 millions:
>
> Margaret Thatcher said once during her term in office that "**Russians
> should be reduced to 15 million**, the persons serving chinks and
> mines". It is open to guesswork why the Kremlin stayed unperturbed
> after the view surfaced, but when it was expressed the confused
> interpreter translated the phrase as 50 million and was corrected
> right away. By all means, this could not have been a slip of the
> tongue - it attested to the seriousness of the intent voiced by the
> Iron Lady with a talent for befriending imprudent Russians that
> Madeleine Albright held almost exactly the same in the mid-1990ies.
>
>
>
This statement was said during the detente after Gorbachev's accession to power, hence it cannot be justified by a Soviet threat to the West (this racist statement was said at a time, when that very threat was being eliminated).
[Answer]
Mnemotechnical Superiority; Engineered Mind.
Along with acknowledging physical - biological identity of the groups, the Supers have developed advanced philosophy; science and engineering of mind constructs. They are trained since childhood in mental discipline, making them able to use their brains as precise, flawless machines that are capable of feats no physical computer could achieve:
* predicting the future (locally up to a few seconds precisely; on society/country/planet levels - years into the future);
* creating an utopian society of mutual kindness, with empathy sense preventing all kinds of painful blunders and immense value of feelings of others;
* performing miracles of science, engineering and art through optimal use of the resources of one's brain;
* engaging in collective thinking - a shorthand language that's equivalent of very fast network communication allowing to form "clusters of brains" far more efficient at solving problems than our unstructured "brainstorming",
* learning any new skills or knowledge with efficiency of a computer
...And above all they are able to realize the superiority of structured, self-controlled, well-designed mind (with a drop of individuality which can contribute to variety and wealth but doesn't destroy the order) versus common mind of ancestors where random thoughts, unordered memories, fragmented knowledge, unchecked impulses, selfishness and laziness were the primary motors of the society.
And there are the "dissenters" who reject the process of structuring. Kids that choose to cheat and slack at the mnemotechnic training, and failed to achieve the coherence of mind; societies that choose to reject the advanced learning techniques, be it living under dictatorships, rejecting the advanced culture, too deeply "poisoned" by religious beliefs to accept ideas that contradict their beliefs (and parents "poisoning" their children that way).
The process requires a young, elastic and unbiased mind to take root. An adult has too many preconceptions, too many developed bad habits - things they'd need to unlearn first before they could learn the structured, superior but far more difficult to absorb alternatives. An 8 years old kid who didn't start the training is already lost to the society; it will forever remain a "monkey".
And of course as the "monkeys" still live in their cruel, selfish, brutish "monkey" ways, with wars, inequity, injustice, greed and need for control over others, lacking in empathy and kindness, they are seen just like monkeys, a previous evolutionary stage that choose not to elevate themselves to the new level of society. They can't be trusted, they are inferior at any jobs requiring intelligence, they tend to be violent, they look to minimizing own work and maximizing own profit at cost of others, they resent the ideals of kindness through disciplined mind and find the cost (effort) of learning not to be worthwhile. Oh, and many of them choose to believe - with absolute conviction - in blatant falsehoods like existence of some deities, and take mortal offense in proofs to the contrary, not being able to understand them with their crude patchworks in their heads.
Of course the kind race will offer a chance to the "monkey children" for a better life, to pull them out of their traps and live happy lives in the utopia. And of course the "monkeys" will fight back...
re:update. Recognition would be as easy as exchanging a greeting in *Express*, the rapid-communication language that allows communication at several kilobytes per second, by combining high-frequency modulation of voice (superior vocal strings control) and additional visual communication channels (gestures, muscle control). Learning the language is obviously out of reach of any unstructured mind.
[Answer]
You speak of "a community of highly intelligent, well-educated and mentally healthy people" as though it would automatically mean they weren't *bad* people, but unfortunately it doesn't. Stupidity, ignorance and emotional instability can fuel and compound bigotry but they aren't the reason for it.
If your basic moral precepts are wrong-- if you don't accept the Golden Rule as absolute, or you define "humanity" to exclude certain groups-- then you can proceed, in a totally rational way, to do terrible things. That's exactly what happened in the fascist societies of 1930s Europe, or Pol Pot's Cambodia, for example.
Many vegetarians would say that if you can empathise with a cow's ability to suffer, and its desire to live, then killing it is no more justifiable than killing a person. There's no logical argument for why cows don't get the same consideration as humans; it's an arbitrary line, and we could just as easily have chosen a line that defines, say, Greek people as food.
If that sounds far-fetched, it's only because of the biological possibility that you could end up with a Greek niece or grandson, which would undermine such a consensus (this is precisely why highly segregated regimes make miscegenation a crime, and it's also why they tend not to be stable over time).
Putting it in these terms sounds disturbing, and it is: if you're looking for a fundamental difference between a "normal" society and Nazi Germany... there isn't one.
[Answer]
If your "accepted" members of your society discriminate against the non-accepted part for some outside reason, they are racists. No point in trying to add any nicer name to it.
To have a justifiable form of discrimination, there would need to be a feature (or lack thereof) in each member of the non-accepted group. This would need to be a great deficiency, like for example the inability to learn to speak, very limited intelligence, an inherent and uncontrollable urge to use excess violence (while at the same time failing to qualify for police work...), or anything along those lines.
No other reason for discrimination is justifiable, so it will not go very well with your accepted group being described as `highly intelligent, well-educated and mentally healthy people`.
[Answer]
Suppose scientists discover a gene or a series of genes that determines whether or not a person is capable of murdering another human being. These people, whom would otherwise be normal in all other circumstances, when put in an incredibly stressful situation *might* resort to murder. These people may be highly intelligent, very rational, and not show any signs of having said gene, however, if the government required that the general population be tested for this gene and publicized the results, you'd find that these people would be alienated.
Although the government wouldn't throw them into encampments, they would be considered second-class citizens in many ways, despite having any legal or moral backing. If you don't think such alienation is possible, then ask yourself how you would act around someone on the sex offenders list. Such a person may be perfectly normal, intelligent, and rational, yet you may find yourself feeling superior to such a person.
Another possibility might be that a portion of the population are androids, whose appearance and behavior is indistinguishable from a normal human being. They could even simulate drawing blood. Yet such an android would naturally want the same rights as other humans, and a good many people would treat them like second-class citizens despite this fact, if for no other reason than the fact that they aren't human.
[Answer]
Prejudice is just statistical inference applied to human behavior. By observing the behavior of a sample of people that share a common and easily identifiable characteristic (skin color, tatoos, unique cloths) you can predict the behavior the population from where the sample was taken. In your particular example lets say I am a member of elite and I only know one unhealthy person. If that only person I know commit murder, I have no choice (because I don't have any other information) but to assume that all unhealthy people are murderers.
I am aware, as an intelligent person, that my evidence do not prove it but if I have to make a decision (trust or not to trust, allow or not them to stay) I must base my decision on the currently available evidence. That is where discrimination takes place. Based on the available information and also based on the impossibility (even because of lack of interest and also lack of resources, and that includes time) of getting more information (in other words: because knowing the ultimate truth is not possible) I will adopt a discriminatory policy to reduce the likelihood of being hit by the undesirable behavior that I am expecting from the unhealthy people.
Discriminatory actions are very convenient because they normally comes with zero cost to people that applies it. Only the objects of the discriminatory actions are more severely affected so from the elite point of view it makes all sense and not doing so would in fact be irrational.
[Answer]
I like the concept and your question is well thought out and interesting.
That said two of your premises are mutually exclusive.
* You have a group of people that were, but are no longer genetically *inferior*
* The genetically healthy from the start population is completely rational and understand the fact above.
In this scenario you have no valid reason to discriminate against those who have recovered from the damage that was done in the nuclear exchange.
Discrimination is based on a few things.
* **Real, or in most cases, perceived inferiority**. Keep in mind we have to talk about potential. I would assume that those born from the healthy lineages have far more education and experience, they have also developed a society that those born outside the system are completely unfamiliar with. So while the newly healthy have the potential to be the same they are *behind* in education and culture.
* **Dehumanization**. This has been tied to every genocide or legally enforced apartheid since the beginning of time, to Rome to modern Jihadists. If you can convince your people that the other people are less human discrimination becomes commonplace and paves the road for systemic violence.
* **Relative Deprivation.** My group should not lose ground to those other people even if I worse off than I was before.
Human nature will certainly allow for your healthy folks to discriminate against the newly healthy, but it won't be based in logic or science.
[Answer]
Really all you need to do is look at how racism has, and continues to sustain itself. Structurally, oppressing groups benefit by having people they can exploit (take their land, enslave them or pay them a pittance, deny them societal resources despite equal or greater contributions, abuse/rape as individuals, etc.) - the excuses as to why this is acceptable is a necessary part of making it an institution.
Culturally, the oppressing group works together to reinforce this, mass media is employed (you can look back to minstrel shows and plays as examples of mass media before we had easy transmission of information), and of course, whatever passes for authorities on reality (religious figures, scientists) produce justifications along the way.
We can see in the modern examples politicians making up numbers that aren't true, the ongoing resurgence of eugenics logic, and biased science studies.
The question isn't "How CAN racism/discrimination survive in a society?" but rather "Under what conditions can we reach a society where people don't exploit each other as a societal practice?"
Educated, sane people have managed to not fix it the last few centuries, and hell, even in the last 10-15 years when tons of evidence about the illogical nature of discrimination is literally a short internet search away - why would you imagine a group under dire survival circumstances and drastic isolation to do better?
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The healthy-descended people can consider the unhealthy-descended people as being unworthy of better treatment simply by reason of tradition. The fact that they're as human as anybody needn't enter into it.
Nowadays we talk of "human rights," but that hasn't always been that important. For many even now, if someone doesn't share your religion / ethnicity / skin color / football team, it's been fine to treat them like dirt, while still acknowledging them as human.
Intelligence and education don't enter into it. Assigning rights to humans because we're all members of the same species is just as arbitrary as any other criteria. Yes, we're far smarter than any other animal on the planet, but so what? Intelligence makes us powerful, but cannot make us objectively more *important.* Importance is, by its very nature, subjective.
So let them continue to discriminate on the basis of tradition alone. They can be intelligent, educated, and well-meaning. Even if their "well" doesn't coincide with ours. Neither would that of most people a few hundred years ago.
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Stereotyped behaviours, perhaps?
Consider culture, for example. If you treat behavioural patterns as organisms, then these patterns use the cultural medium to procreate. So people within one culture tend to behave similarly. Our parents spread their culture onto us by upbringing, so we tend to be just as irritable or kind as our dads and moms. If our culture also has an apparent distinctive characteristic, then our behavioural patterns will get connected with this distinctive characteristic.
For example: wearing a hijab is very apparent and is common among Muslim women, so seeing someone in a hijab we assume they are Muslim (and with this comes the assumption that they will pray on midday, which is a behavioural pattern), but that is not necessarily true, since any non-Muslim person can wear a hijab (even a man).
All you have to do is to create a culture, of, for example, cannibals, who practice a monthly sacrificial feast at which they eat a human being. Otherwise, they are pretty ordinary farmers who… pierce their eyebrows, perhaps. They live in a rather technologically unadvanced society and get on by the sweat of the brow and strength of the back growing them cucumbears (yes, I know there's an “a”) and whatnot, hunting the wild wolf-pig or whatever else. So now you have a reason to believe that a person with pierced eyebrows a) eats another person once a month, b) is unambitious (otherwise the farming culture would have at least perfected farming task automation or something, creating a steady breed of brilliant engineers).
The key is to make a statistical correlation between an antisocial/degrading behaviour and an apparent characteristic (apparent as in one which can be easily identified).
Once you do that, you will have your stupid blondes, slutty nudists or whatever else type of discrimination you wish to create.
Now, with increased complexity of circumstance, your apparent characteristics might become less apparent… such as behaviour as your characteristic. If people who engage in fraud tend to ask significantly more personal material gain questions than others, then you might conclude that a person uncommonly deeply concerned with personal gain is contemplating (or has committed) fraud, so now you are prejudiced towards (or against?) selfish materialists.
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There is nothing "insane" about discrimination, it is one of mankind's basic impulses for survival. It's a natural biological response to feeling vulnerable which is no different than withdrawing when you feel sad, or lashing out when you feel angry. The things we "feel" are not based on what help us survive today, but what helped our ancestors survive for the past few million years. During the last couple of ice ages when resources were scarce, we had to determine ways as a species to decide who we want to share our resources with to make ourselves a stronger tribe, and who we need to protect our resources against to keep ourselves from becoming over-stretched and starving to death.
To help us with this problem, our minds evolved to look for differences between us and other people. How big or small those differences are is irrelevant. What matters is that we place others on a spectrum as more or less different than ourselves. This helps us prioritize our genetic lineage above others which is key to the selective fitness of social animals. Even if we were all caucasians with blonde hair and blue eyes, the people with narrow noses would start distrusting the ones with wider noses pretty quickly because that's just how we are wired.
But there is a second factor to discrimination which is scarcity. In times of plenty, discrimination naturally wains which is why when you see a civilization start to flourish, it's often accompanied by an expansion of civil rights, and when a country's economy struggles, you see people respond by becoming more factional and biased. You only see it less in well educated places because that education is often accompanied by wealth, self-sufficiency, and faster recovery from economic crisis.
That said, any civilization that is continuously strained for resources will find ways to rationalize discrimination regardless of intelligence, education, or health. The longer the scarcity lasts, the deeper the policies of discrimination will take root in your society's laws and cultural standards. So, to create the society you are looking for, you just need to solve the problem of creating long lasting scarcity despite good education.
I don't think your idea would necessarily work as is because your well-meaning smart people would become wealthy and wish to help the poor and desperate masses of mutants (thanks to our instinct to grow our tribe). If you want a discriminating intellectual class, they need to themselves experience a real risk from allowing equal rights. To do this, I would suggest having the intellectuals seal themselves off from the radiation and enslave the mutants with their superior technologies. Make the mutants get sick and die working the fields while the intellectuals stay safely in their bunkers. When the radiation is gone, the intellectuals have no resource infrastructure of their own; so, they can not release the mutants from servitude without jeopardizing their own survival.
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I want a weapon that can:
* Chew through reinforced concrete like it were popcorn,
* Blast through 4-inch frontal armor plating of tanks like it were papier-mâché in the wind
* Has a high (or continuous) rate of fire, or makes a high rate of fire unnecessary through sheer murderous awesomeness.
* Be man-portable (a grunt can carry it and use it in a firefight).
Initially I was considering railguns, but I'm starting to suspect the combination of iron plasma and the recoil would probably kill even exoskeletoned and full-body armored infantry.
**So what will my Death Legions wield?** Lasers? Relativistic shard guns? Some sort of particle weapon? Superacid projectors? The relevant criterion is that they be conceivably manportable and not physically impossible (even if not *feasible* now, and even if heavy enough to say require a powered exoskeleton, but must be possible and plausible -- i.e. no known way to manipulate gravity besides moving heavy objects around).
Edit: Have been asked about Tech level. I'm quite flexible, from near-present to advanced-miniaturized-fusion reactors, maybe even very early antimatter tech. I'd steer clear of Zero-Point, since a mug's worth of empty space energy could boil our planets oceans. Seems like overkill, even for Marines. Generally, the sooner I can have them, the happier I am with the answer, so slight bias towards presently reachable tech.
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As other mentioned, there is no scientifically plausible way to pack energy dense enough to be man-portable for your usage. Nuclear weapons are not portable enough, and chemical energy in explosives is the densest we can do now or in foreseable future. We don't know how to make backpack fusion generator to power lasers.
So let's add sufficiently advanced technology (which we cannot distinguish from magic): Backpack-portable matter-to antimatter converter. It swaps electricity charge in nuclear particles, making positrons from electrons, and anti-protons from protons, keeping total charge the same, and not needing any energy to do it.
Now you can pick pebbles, feed them to your converter, and annihilate your opponent. Only energy you need is to accelerate your anti-pebbles, which is easy. Bring lots of sunscreen, it will be bright!
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Each of your Death Legionnaires should be equipped with an AK47 assault rifle, loaded with bullets laced with inactive nanite disassemblers. The barrel of said AK47 should be tipped with a combination silencer/nanite-activation device such that as bullets leave the weapon, the nanites inside them start waking up. By the time those bullets reach their targets, the nanites are ready for breakfast.
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**LASERS**
If you can get the energy density, a megawatt FEL will burn through 20 feet of steel per second. Which should be enough to do the damage you want. Needs some technological shrinking (it's a shipboard weapon) - but they were well on their way to this in 2011.
Cold fusion backpack reactor?
(corrected, thanks: ckersch)
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As Samuel notes in comment there are some pretty serious energy density issues. Apart from the difficulty of storing enough energy, there is a serious problem with the side effects the release of energy has on the user. With both kinetic weapons and energy weapons a significant percentage of usable energy would be released as heat and pressure waves at the weapon. As such the only real solutions are liquid projectors and weapons shooting explosive grenades where these side effects are suffered by the target.
Liquid projectors have two issues. First, they generally are area effect weapons and have poor penetration, which does not match the desired effects. Second, while there are chemicals dangerous enough, dangerous chemicals have an annoying habit of being dangerous. I can't really think of a safe way to go beyond melting or igniting armor. And that type of effect is very different from what you want. You'd probably kill most things you attack, though.
If we dropped the plausibility requirement and assumed a "nuclear stabilization" technology, you could have particle accelerator shooting ions of unstable isotopes of heavy elements. The ions would then penetrate armor and decay inside it. This would destroy almost any armor eventually with an effect matching the desired one.
A weapon shooting [HEAT](http://en.wikipedia.org/wiki/Shaped_charge) grenades would be the one plausible way to get the effect wanted. Every hit destroys some armor and weakens the area, so a weapon capable of doing accurate rapid fire with even small HEAT grenades would disintegrate the armor. A four inch armor was mentioned. That is roughly 116 mm. Wikipedia gives a typical penetration of 7 times the charge diameter. That would suggest that a 30 mm HEAT warhead could penetrate up to 210 mm with optimal design and circumstances. Since we only want half of that and are more interested in destroying the armor than penetrating it, 30mm or even 25mm should be enough.
An automatic weapon shooting grenades in this range is plausible, as is a man portable weapon shooting grenades this size. As HEAT does not need high muzzle velocity, recoil compensation should be an solvable issue.
There is one serious issue, though. The weight of ammunition. A 25/30mm HEAT grenade isn't that heavy, but if you want to fire them full auto to **really** chew through walls or armor... Well, with a special carrying harness and ammunition belt-fed from a backpack. Why not? I sure wouldn't want anyone to shoot me with a weapon like that.
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How about a miniature belt-fed rocket launcher with 3-stage rockets?
Stage 1 merely gets the rocket to the target, so you aren't wasting too much force on recoil. Once it gets there, it clamps on to the material it hits and fires off stage 2.
Stage 2 acts like a shaped charge and drills through the material using the first stage as a back plate.
Stage 3 blows up.
There you have it. A shoulder-mounted semi-auto bunker-buster. Maybe stage two doesn't get all the way through your 6 feet of concrete, but after stage three puts a massive hole in it, two seconds later you are hit with another round.
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I would guess you're going to need something like the 25mm cannon on the Bradley fighting vehicle. I would expect it to be a smaller caliber to make it portable (maybe a team of 2 or three) and it would have to be set up to use (we already have teams and emplacements for the 50 Cal.) The big thing the 25mm has is multiple types of ammo available. Mostly High Explosive (HE) and Armor Piercing (AP) rounds, but that doesn't mean more couldn't be designed.
Of course the problems are that you want to punch a hole in something and other times you want to 'blow it up'. There might be other problems to, like needing to disperse groups, so having some tear gas rounds could work for that.
Punching holes usually needs mass traveling at high speeds, which means something has to push really hard on it. Newton explains how that works.
Lasers as weapons are problematic primarily because of the sheer power needed to burn a hole in anything worth burning a hole. acid? problem getting enough of it to the target to do good, especially more good than a high velocity round. Acid is also pretty slow when compared to other types of weapons.
EDT: Just thought I'd add, Zion in the matrix was protected by people in Exoskeletons with 25mm Vulcan canons
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The main problem you have here is recoil, anything you fire out forwards pushes the gun backwards.
This can be fixed if we make the bullets self propelled (essentially tiny rockets). Antimatter would provide sufficient energy density for this. For bonus points the remaining antimatter would cause a small explosion when you strike the target and the result would be catastrophic for anyone hit as these bullets would be high caliber, extremely fast, high explosive force...and would even home in on the target with a very basic guidance system.
From a technical/scientific point of view the antimatter would need to be generated somewhere, but the real trick is going to be storing it.
If the antimatter is stored in the bullets then they would need some sort of hard vacuum chamber suspending the antimatter in the center somehow. Containment breaches would be bad and very hard to avoid.
A more likely system would be to have the gun store or even better (safer) generate the antimatter on demand (this would involve some serious power sources though so containment might be the only option) and the bullets are filled with antimatter as part of the firing process.
An enemy strike on the antimatter reservoir of a gun would be seriously catastrophic for anyone in the area though. Expect shielding those to be a high priority.
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What you want is a Davy Crockett device.
<http://en.wikipedia.org/wiki/Davy_Crockett_%28nuclear_device%29>
It is a man portable nuclear launcher. It has a high rate of fire, lots of destruction power and can render areas uninhabitable.
Its problem was that they killed the program. If it had been continued, the accuracy problems would have been resolved, smaller devices would have been made, small enough to be carried by a human(javelin size is small for this sort of things).
Mount these on an a-10 and you have one big terror weapon.
p.s. OP wants a weapon of utter destruction, so radiation is a up-side on this matter. He would likely never try to clean it up.
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Just use a two-barrel gun.
The simplest two-barrel gun is capable of destroying a bunker, if you load it with antimatter bullets. The only issue is the design of the bullets themselves.
So, a standard cartridge has three parts: bullet, case and gunpowder. Do not modify case nor gunpowder, but make the bullet a bit different: an antimatter container. A small amount of antimatter suspended in an electromagnetic field.
When the bullet impacts the tank or bunker, it just breaks, like any other bullet. On doing so, the EM field device just breaks as well, the antimatter gets released, contacts matter, and givs you a shiny beatiful explosion.
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While I agree with Peter Masiar that the energy density is unobtainable I don't think you need to violate the laws of physics that greatly to get a solution.
Rather, lets hypothesize a device based on extreme gravity control--able to project internal fields approaching those of a black hole. The weapon consists of a tube with the generators in it and whatever support equipment is needed. When fired the weapon sucks in air from the back and uses it's gravity field to pinch the flow through an incredibly tiny and incredibly thin aperture. The result is fusion--but since it isn't instant the fusion occurs on the far side of the aperture. Some of this energy is captured to power the weapon, what isn't captured comes out as a plasma beam moving a few percent of lightspeed.
You'll probably want to tone the weapon down a bit to keep the radiation from the beam from frying the operator. (This wouldn't be nearly as much of an issue if the weapon were being fired by someone in powered armor.)
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This is similar to the answer of Peter Masiar, but not quite the same: I Think the best way is to use a positron beam. Positrons are the antiparticles to electrons. They are very lightweight, thus they'll not create a big recoil even if you pump out lots of them. And they'll annihilate with electrons in matter. Since the electrons are ultimately what holds the matter together, a sufficiently strong positron beam will effectively destroy matter. In addition, the annihilation will release a lot of energy, so anything surviving the annihilation will then be destroyed by the generated heat. As a bonus, it generates hard gamma rays, so you'll kill the victims even before the ray has eaten through the material all the way to them.
Main disadvantage: The gamma radiation goes in all directions and thus will probably also kill the shooter, so portable antimatter weapons are really only for suicide terrorists. Well, unless you manage to create a body suit that protects from hard gamma rays.
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Make a nuclear suitcase using Californium-252. Its minimal critical mass is 2,7Kg. Thats equivalent to a pretty heavy wallet at circa 10kg with all supporting devices. Caveat is that Californium is a powerfull neutron emitter and no lead in a wallet will block this and stay man-portable. You must accept that delivering it is a suicidal mission. Another caveat is price, Californium is not a naturally ocurring material. It is created inside nuclear reactors, so it is quite costly to recover.
References:
[Californium](http://en.wikipedia.org/wiki/Californium)
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If you are willing to create new element with a low critical mass you could have small nuclear explosives. If critical mass is a few grams it should still powerful enough to destroy a tank or a building, but would fit in a large caliber bullet (20 mm or so). Of course a burst from that would be pricey.
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Trying to figure out a method for a teleportation machine that definitely does NOT "kill" the user in any way. The big thing is preventing a loss of consciousness during the process. Even if it gets a little weird in there, there should never be a point at which your brain's molecules have been individually separated and turned into energy or anything like that. What I'm looking for still involves the user themself moving around in space in some way during the process—e.g. you could end up swapping places with a buddy in the same teleporter as you between point A and B—whether it's from some spatial warping within the interior as the structure teleports between points, or if it's because it's JUST the user that is moving, independently of the teleporter structure/interior.
In short: how would a teleporter work in a way that includes warping the physical/spatial existence of the user themself (so your body might get pushed and pulled and warped around a bit, maybe even spatially merge a little with your aforementioned buddy during a particularly rough teleportation, but it WILL NOT HURT—*is that possible?*), and involves moving or "blinking" the users **(or teleporter interior!)** from point A to point B, in a method that doesn't kill the users, cause any pain, or even cause a loss of consciousness?
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The more or less classic way to do this has been a portal, wormhole, etc. Think of the tunnels in *Tunnel in the Sky* or the Gate in *Stargate* et. al.
These effectively amount to connecting two distant regions of space together, so that a simple step takes one from one side to the other. They may be one-way (like Stargates) or two-way (as in *Tunnel in the Sky*). They may, as in Hugh Cook's *The Questing Hero* or *Fringe*, be subject to unpredictable or uncontrolled shutdown, with fatal results if you're halfway through at the time -- but in normal operation, at least from the correct side, they're effectively just like stepping through a doorway (possibly with a wormhole-traversal special effect inserted along the way).
In some cases, the gate itself can be scanned over a short distance (similar to *Stargate*'s ring transmitters), so the subject of the transport need not move.
Another form of this method is from the novel *Jumper* (*et sequelae*) by Stephen Gould -- in this case, as shown (internally) with slo-mo video, the protagonist opens a portal the shape of himself (plus anything he's carrying) and passes through it -- in this case, with some screwiness relative to conservation of momentum. Something similar is found in the "flinging" of *The Adventures of McGill Feighan* by Kevin O'Donnell Jr. -- only there's no hint of the visible portal, and the flinger has conscious control of momentum compensation.
Regardless, in no case do these disassemble atoms or particles and reassemble them at some destination; rather they bring *here* and *there* together momentarily.
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The "bending of space" is one possibility - the easiest. Basically, it's magic. It can do and behave as you like.
One way more far-fetched but philosophically intriguing possibility would be to employ technology capable of simultaneously mapping and interacting with individual atoms at the scale of the human body. Machines capable of pinpointing a single hydrogen ion and push and pull it however they want (similar to Iain M. Banks' *effectors*, but *more*).
More than that, they can focus on all atoms *around* that one proton, and push and pull them *as if the proton was there, even if it isn't*.
And they can do this with *trillions* of atoms at a speed of several thousand trillion atoms per second.
At that point, we can "transport" a person using a modified [Ship of Theseus](https://en.wikipedia.org/wiki/Ship_of_Theseus) process: we take the person, and we start removing atoms from the surface. The information about the atoms is transmitted to the receiver, where the required atoms are gathered and assembled. The person is still alive and feels no pain while being dismantled, because all the parts behave exactly as if they were still connected. Some atoms have to be "transported" to and fro several times, for example those in bodily fluids.
Halfway through the process, we have half a person *here* and the other half *there*, but they're still connected (if we want to enforce light-speed, then the two locations cannot be very far - probably no more than very few kilometers. More, maybe, using repeaters and "slicing" the person between them all).
Except some double vision and some disorientation, the person reintegrates at the destination, all their atoms replaced and maybe their *soul* lost in the process, but they never died, their sense of self was neither lost nor interrupted.
Now for something even more challenging -- what if the "destination" was actually a *simulation*? Now the person "exists" as computer data, and can be "frozen" and sent along to the real destination, and the process can be reversed there (in multiple copies, even)...
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**You are copied down to the electron, and a new version printed at the destination.**
If you are snuggly with your buddy when you get copied the copies might get mixed up some. You do not die. In fact nothing happens to you except you stand there while various beams scan your stuff. Then there are some beeps which means it is done and you are free to go the bar.
You also open your eyes to view your destination once the new version of you has been printed there. You can go about whatever business you have at the destination. Possibly wearing that swanky amber necklace your buddy wears.
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## Actual Teleportation
Teleportation is the act of changing the position of something without moving it through the intervening space. Wormholes are just shorter distances of intervening space, while breaking you down into (sub)atomic particles just introduces the complexity of (dis)assembling you correctly. Instead of trying to teleport bits and pieces, just exchange the entire teleporter contents at once.
Now you may be wondering, how does this actually work? In quantum mechanics, an electron doesn't have a position, but instead has a probability function of where it could be. With the appropriate quantum manipulator, you can modify this probability function, effectively shifting the position of it. That would allow you to shift as single particle, but we want to move entire people. So we use the quantum aggregator that allows us to apply quantum effects at scale. This allows us to manipulate the probability function of the entire volume at once, transposing it with the contents of the other teleporter.
At least that's what the strange man in the labcoat says. From the inside, it feels more like an elevator. You step inside and the doors close. There's a brief lurch and when the doors open everything outside's different.
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# Have a spaceship do hyperspace travel
Have an alternate dimension where distances are much shorter. When you step into the teleporter, the ship flies you wherever you need to go, and then you get off.
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Do it gradually. First replace each neuron with an antenna to a server. The antenna acts with nearby neurons in the same way that the replaced neuron did. Eventually the person's brain is fully antennas and they "live" on the server. Then find them a body at the ending location and repeat the process in reverse.
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**A classical teleporter with a feedback loop**
The classical teleporter would tear you down, atom by atom, and reassemble you at the target.
My modified version of the teleporter would tear you down starting from one end (e.g. from top to bottom), but while disassembling the user, it would simulate the effect from the already removed layer onto the next layer, and do the same on the assembly side.
Say, for example, layer A was already removed and teleported, while the next layer (layer B) is still at the original site.
Instead of just removing and recreating, it would simulate all effects that layer A has on layer B (e.g. the weight of your now-missing head pushing down onto your still-remaining body) and vice versa (e.g. your not-yet-created neck holding up your already recreated head).
This would, obviously, have to happen on a sub-atomar level, not on a body-part level as I described it above.
This way, the user wouldn't feel the difference, since the effects of all missing parts is simulated.
The teleporter thus only needs to work on two layers of atoms, instead of on the whole body at once.
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## A Time Machine
I don't recall where I read this idea (it's not mine), but one way to do this is to travel (normally) to your destination, then activate your Personal Time Travel DeviceTM and travel back in time to when you departed. To an outside observer, you arrive at the destination at the same time you depart.
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Well, you know, there are theoretically methods for digitizing the brain that preserve the continuity of consciousness? Yes, replacing neurons with artificial ones one by one. Or analyze a few neurons - delete them - connect to the area they had influence on and simulate their activity, so at the same time you will become platform independent lol. Both methods have already been explored in science fiction, the first for example in the quantum thief, the second in Vinge's story iirc
I've been thinking, in the same way it is possible to make teleportation with the destruction of the original continuous.
Two plates can be made, each plate is connected to the nervous tissue and exchanges a signal with the other plate. That is, each simulates the presence of nervous tissue on the other side in real time with a negligible lag. To do this, of course, it is necessary to add or remove blood from the vessels, replacing it with synthesized one.
If you slowly begin to pass one of these plates through a person, and synthesize the disassembled parts on the other side, while continuously maintaining the connection, then the person will not lose continuity, they will be conscious all this time, even when one half of their brain is kilometers from the other.
In this way, you can teleport no more than (informed guesstimate) 10 kilometers, then the lag due to the speed of light will increase too much. The problem can be solved by ftl methods of transferring information or by intermediate stations or by a preliminary continuous transfer of consciousness to a substrate that suffers less from lag between parts.
Of course, the problem of Theseus' ship remains, but this is not so important, people already regularly replace all the atoms in their bodies, and feel fine
(all this is said taking into account sufficiently advanced technologies, but not straight magic, just more or less technology that is conceivable with the current course of development in the distant future)
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## A knife
Philip Pullman in [His Dark Materials](https://en.wikipedia.org/wiki/His_Dark_Materials) book came up with the idea of the Subtle Knife, a knife that can cut through reality and allow you to travel to other worlds. It was an actual cut in the air that opened a breach.
This was also used in the Lucifer series: <https://youtu.be/OD8gvoXG4Xc?t=110>
You can adapt that to same-world travel, where you just get into the tear as if it was a door.
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Basically I'm trying to create a combat situation and training where recruits and people on the front line are expected to burn 6,000 to 7,000 calories a day. Now despite how messed up the war is against these foes, which are aliens, they seem to operate themselves on very good conduct given this is a genocidal conflict.
It is the year 2030 and aliens have invade earth for unknown, to most of humanity, reasons. But the war is now a brutal slog. Despite this, as said the aliens conduct themselves, relatively well to us.
One of these is that they allow their human opponents the right to "four square meals a day" during meal times. And surprisingly enough, if you actually give your all the aliens actually take you alive and treat you reasonably well.
Given that their eons more advanced than us the war from their perspective is just a small scale species change/diplacement/breeding. From the human perspectives though its a brutal conflict for the survival of our species.
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**Put them in Antarctica.**
[](https://i.stack.imgur.com/vIHwh.jpg)
<https://www.ncexped.com/polar-expedition/polar-expedition-food/>
At Sea World San Diego there was an exhibit that included a kitchen for Antarctic explorers. It included sticks of butter. Each explorer ate one or two a day to meet caloric needs. The cold means your inner fire needs much fuel.
>
> Two things were found out very early on in Antarctic exploration -
> that extreme cold makes people feel very hungry and hard work such as
> that involved in travelling by dog sledge, or especially by manhauling
> uses a great deal of energy. This energy had to be replaced by eating
> enough, unfortunately the early explorers didn't eat enough and
> suffered as a consequence.
>
>
>
>
> We now know that the following Antarctic activities use per day for an
> adult male:
>
>
> Manhauling sledges 6,500 calories (27,300
> KJ)
>
>
> Travelling by dog sledge 5,000 calories (21,000 KJ)
>
>
> Travelling by skidoo 3,350 calories (14,070
> KJ)
>
>
> Working mainly inside buildings 2,750 calories (11,550 KJ)
>
>
>
<https://www.coolantarctica.com/Antarctica%20fact%20file/science/food.php>
Bonus is that I cannot remember reading or seeing about a battle set in Antartica.
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**Marching**
Military marching is a strenuous exercise. It burns 300+ calories/hour if marching without load and 400+ calories/hour if marching with pack/weapon. Add mud or rugged terrain, and caloric requirements would go higher. If soldiers are required to march several hours in a day, they can require 6,000 to 7,000 calories/day just to keep going.
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**Four Hours Running**
[](https://i.stack.imgur.com/nikCy.png)
If you look up the diet and exercise routine of Usain Bolt you will see he does something like 4 hours exercise every and 6000 calories.
Of course Usain needs to eat more than normal people because he is bigger than a normal person. Nearly early 2 metres long in fact! So perhaps a smaller person needs to run for 4 hours while carrying heavy army gear.
This also answers the follow-up question of where the food comes from. The aliens air drop pouches of McNuggets with little parachutes onto the battlefield.
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A few hours long duel in a labyrinth that actually is an arena will be enough to burn a lot of calories. Often in combat the aliens push isolated soldiers in a closed area and then one of them takes on that soldier in a one on one combat. The soldiers must be trained on this kind of duel.
For the aliens they are nothing more than gladiators games. For the men it is matter of survival. The heart pounding at a crazy rate. Move back and forth, left and right, run in circles. Elude the challenger and then catch them by surprise. High on adrenaline all of this will cost a lot of energy.
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Marching was already mentioned. But you forget an occupation, ancient world soldiers' were exposed to in large amounts.
# Building
Let your soldiers build stuff. Bridges, walls, camps, roads. Some of that they'd need for the campaign. Some not. Building in times before steam or internal combustion engines means a lot of physical work. Probably, all the woodwork would need to be sourced by the army, which means even more lumberjacks. All these are physically exhausting activities, warranting large amount of intake calories.
Make the soldiers accelerates, i.e., the modern body type and size – large men need more calories. Extreme, professional sports or extreme weather conditions would require to reach such intakes.
That's the gist, now let's check the harmony with algebra.
# The formula
I've dug up a formula on needed calories based on body parameters and activity:
$$(88.36 + (13.4 w) + (4.8 h) – (5.7 a)) \; c,$$
where:
* $w$ is weight, in kg
* $h$ is body height, in cm
* $a$ is age, in years
* $c$ is the coefficient for workload type, e.g., 1.2 for no load and 1.9 for heavy load.
Now, let's search for a good parameters. Let's say, the whole army is build from 190 cm tall, 20 years old guys. The top margin of healthy BMI says, they would weight 90 kg. (Let's pretend, it all muscles, not fat.)
These values yield something shy of 4000 calories. Even if we force then to inhuman, bone-crunching work, and raise $c$ to 2.2, that's still only 4600 calories. Too little.
(Notice than while praxis has seen the consumption of the desired amounts of energy, that's not what regular mortals' dietologist would approve of for regular life. So, either make their life really hard, per above. Or – keep reading.)
A normal human does not suffice. So, let's go Warhammer.
# Superhumans
Let's take a three meter tall space-marine breed. Scaling up 1,5 m to 3 m height scales up the weight 8 times (because of square-cube law). Let's say, that's 400 kg.
Per above formula, those guys would need more than 8000 calories even idling, and 12000 when heavy working.
# Byline
So, you either need to work your soldiers to the bone (by forcing them to do hard manual work all the time, by marching insane distances, or by conquering Antartica), or you need *larger* soldiers.
[Answer]
They wear **heavy advanced combat spacesuits** which take significant muscular exertion just to wear. (This answer is inspired by the excellent long-running fiction [*The Deathworlders*](https://deathworlders.com/).)
If this war involves aliens, presumably your soldiers have to be able to fight in extraterrestrial environments. They wear a suit which functions as protection against the vacuum of space and other hazardous environments and armour, as well as being loaded with the typical heavy weaponry, ammunition and equipment that soldiers today carry. In order to function it compresses the body tightly and is also extremely heavy, so just wearing it is a constant full-body workout.
[Answer]
You've got a big problem here--for a normal-mass human the digestive system is pretty much incapable of taking in that kind of energy. Probably the highest sustained-energy activity people engage in is thru-hiking and they generally top out in the 4000-5000 calorie range.
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[Question]
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Imagine a certain nation tested a hypersonic nuclear-capable missile and it was designed to make a few trips around the Earth at low altitude before striking the surface. Don't they need to worry about the prolonged period of time the missile needs to survive the temperature of aerodynamic friction from air colliding with the missile? It increases exponentially with speed and at hypersonic velocities (5-10 times the speed of sound) the temperature around the missile should melt most metals known to science.
My question is why risk a nuke since so far no one is capable of intercepting it anyway? Why not just plot a direct route and let it scram at low altitude until it crashed into the target zone if efficiency is all that matters?
[Answer]
1. No need to orbit in the atmosphere. The ballistic trajectory goes outside the atmosphere, where there is no air, no friction.
2. No way a rocket could fly a few trips around the planet in the atmosphere anyway. Energy-wise, it will run out of fuel going against such drag.
3. Even if re-entry is to be endured for a long time, we have materials for that. Ceramics and heavy metals can withstand it. The temperature of plasma near the ship will be larger than the melting point, but the surface will not be as hot.
4. It is actually easy to intercept low orbit stuff. The energy required to intercept a low orbit is about 10 times less than the energy needed to go into that orbit. Even much less technically advanced nations can intercept an orbit, even if they can't go there. Lots of our anti-air rockets designed to hit a plane can intercept a low orbit, actually, with very few changes. The chances for a successful interception are much lower than for a plane unless changes are significant, but still, numbers can help, and no bleeding edge tech is needed.
The reason why orbital weapons are so deadly is that they can stay in orbit for years. Not just 3 turns, but thousands of turns. Then it is more of a weapon storage, that can be utilized at any point in time. If there is no war yet, and a nation puts nukes in orbit, then another nation needs to either intercept them right now, before they activate, or just accept that they can't do it later. Once a nuke decided to drop from orbit onto a target - it cannot be intercepted, not even by most modern tech. Nukes can only be intercepted in the speed-up phase, or if they are staying in orbit.
If you know that a nuke is going to hit in 20 minutes, it is somewhat better than not knowing when it is going to hit at all. A nuke from orbit can wait for 3 years, and then drop in just 3 minutes. Normal nukes with their 20 minute delivery time give at least some time to run to a bunker, or launch a response. But orbital nukes with their delivery time of just a few minutes give no such chances. You either live in a bunker, or just accept that you will not have a chance to get to it.
[Answer]
# Loitering
First, a hypersonic-capable missile need not remain at hypersonic speeds for its entire flight. Many missiles differentiate thrust between cruising and final approach, saving sprint speeds for the last leg.
Further, if the missile uses a [nuclear ramjet](https://en.wikipedia.org/wiki/Project_Pluto) as opposed to conventional rocketry, it could have a tremendous amount of endurance (neglecting all the reasons that's a *bad* idea), so in a major war situation, these missiles could be launched and set into holding patterns, circling the planet (or the target country) until commanded to go into their attack patterns.
Because they're so fast, the enemy has no way of intercepting them, so they provide a credible, and threatening, second-strike capability. But the time in loiter mode means that they can also be *aborted* without hitting their targets.
[Answer]
**Sending a strong message**
Of course there is no need for the missile to circle around Earth before striking its target. Furthermore, as other answers and the question itself had mentioned, cruising at low altitude present enormous technical challenges which no nation had been able to solve so far.
Then why the attacker should take such a long time before the strike? The answer is to let the opponent know about its intentions. Traditional ballistic missile, or traditional cruise missile (or "traditional" hypersonic missile, for that matter) cannot be called off. It can not change its initial target either. The only option for the attacker is to self-destroy the missile mid flight if the attack needs to be aborted - and this option is often not available.
Thus, when the traditional missiles had left their silos, the world is already past the point of no return. Even if world leaders suddenly come to their senses and want to fix everything, it is hardly possible to do so.
Here comes a world cruising hypersonic missile. This missile is more akin to traditional nuclear bomber which can be called off - only much, much harder to intercept. After the launch, opponents would quickly know that there is an impending strike - but there is nothing that they can do except to negotiate with the attacker.
This answer assumes that cruising hypersonic missile is able to communicate with its flight control center.
P.S. I realized that my answer is essentially a variation of @jdunlop's answer.
[Answer]
>
> Why not just plot a direct route and let it scram at low altitude until it crashed into the target zone if efficiency is all that matters?
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1. That's how you get intercepted mid-flight.
2. Define efficiency. If a 500,000 dollars missile can demoralize the enemy with one shot when 50,000 dollar ones can't with 100 shots, which one do you prefer?
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In the ongoing invasion of Ukraine, Russia is using their new Khinzal hypersonic missiles. They are not relevantly faster than other missiles that NATO, China and India have available - but they are extremely maneuverable (when compared to regular missiles, they still turn like any other rocket). In other words, they are not ballistic. They make random turns while in flight to evade anti-missile barrages. Some variants do go up to the higher atmosphere and possibly beyond.
The Khinzal spends most of its time flying at Mach 4, but can accelerate to Mach 10 at sprints. For comparison, India had the Shaurya which goes to Mach 7.5 in low altitudes, but is ballistic, since 2011 at least. [The US might soon have a hypersonic missile capable of reaching Mach 20](http://en.m.wikipedia.org/wiki/AGM-183_ARRW). And China has anti-satellite missiles, which necessitate hypersonic flight and high maneuverability. So while this is all literally rocket science...
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> Don't they need to worry about the prolonged period of time the missile needs to survive the temperature of aerodynamic friction from air colliding with the missile? It increases exponentially with speed and at hypersonic velocities (5-10 times the speed of sound) the temperature around the missile should melt most metals known to science.
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... That same rocket science has already solved those problems time and again.
[Answer]
## Mass panic puts time pressure on negotiations
Q: *"My question is why risk a nuke since so far no one is capable of intercepting it anyway? Why not just plot a direct route and let it scram at low altitude until it crashed into the target zone if efficiency is all that matters?"*
For *some reason*, the agressor decided to let the missile fly multiple rounds in the atmosphere.. at Mach-5, that will take about 6-7 hours for a round trip, depending on latitude of the flight path. It could be up there, for a day or two. I'll skip the feasibility analysis and technical frame challenges "it's a waste to do this", other answers have covered that. This is an attempt to improve on Alexander's answer. Why would this weapon be the perfect way, to put pressure?
**Extremely low orbit will not allow secrecy to prevent panic**
Say 200-500 feet altitude, modern guided missiles can do that. All the time, this frightening nuclear missile will fly over your populated areas, multiple times, visible to everyone in the target areas. It will be in all the newspapers. And feel like Russian roulette (what's in a name)
**Uncertainty: no tactical or strategical response, it could even be fake**
The defending army would get intimidated - air defense will do 3-4 attempts to intercept the thing.. and no attempt will succeed. That would undermine army moral. Especially at high command levels.. your country is a super power, you have many places around the world this missile could be intercepted, but it does not succeed. To deploy this missile is a new strategy that's not in the books, there is no response either. The nuclear war head mounted on the missile could even be *bluff*, nobody knows for sure.
**Time pressure on negotiations**
Suppose you have to negotiate with the aggressor. His missile flying around for a day now, during the negotiations. The aggressor has the means to challenge you with a turn-key acute threat. This nuke can (and should) be cancelled at any moment, the aggressor needs to do that. If it does not happen, you can't prevent the damage and the aggressor has not even indicated a target. This would put enormous pressure on negotiations to give in, and meet demands quickly. You'll *beg them* to crash this hell machine into the Pacific ocean.
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[Question]
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I am currently writing the world, setting and characters for a project of mine called the ORION Project - a story set in a dystopian America in the near future of 2050, where the government has taken complete control over its people, and doing anything to keep it that way. After a nuclear and energy warfare, an American energy research facility blew up, causing unknown radiation to spread across the continent.
But that's just the background of my story, and since it isn't *that* relevant to my question, I'll just jump to the important part.
On Earth, superpowered people have always existed, but these people were rare, and hid their powers as they had a human appearance. These people, were called Meta-Humans, or for short, Metas. But ever since the energy catastrophe, the radiations have altered the newborn Metas' DNA, altering their appearance and ability to hide their powers. Their appearance didn't look exactly the same as humans now, for example, markings, strange eye color or skin color could be found on them. Because of that, humans began raising suspicions, and so in the end, Metas were discovered by humans.
And so this is where my questions comes in. These newborn Meta-Humans were taken into government labs as kids to study their abilities. This project was called the ORION Project, and the sole purpose of the project was to study Metas and their powers, while trying to replicate those abilities on actual humans. And so the main character of that story is Astrid, a Meta-Human who was taken in at the lab at age 6, and stayed there ever since. Although her real name is Astrid, she is called by her code name 006, and her memory of her name was altered so that she wouldn't remember it. But that's besides the point. At age 6, Astrid came into the lab, and was experimented on in all sorts of ways, unethical or not. And so here is my question:
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> During one of the tests, Astrid is injected with a chemical that is usually harmless to humans, but that causes an unusual reaction for her, as a Meta-Human. Astrid possesses markings under her eyes and on her hands, that glow bright red along with her eyes when she uses her telekinectic powers, but also when she feels strong emotions. Inside these markings is an unknown orange substance that travels throughout her whole body thanks to an additional secondary system of vessels created specifically for the purpose of carrying this unknown substance around. So coming back to the tests, Astrid starts feeling dizzy and has an accelerated heartbeat, as well as a hard time breathing. Her arm feels numb and her markings start to glow for no particular reason. Since the scientists see the subject is nearing death, they have to remove the substance they injected out of her body, or at least be able to save her. My question is: **Is it possible to do such a thing? I'd prefer an answer involving as much scientific accuracy as possible, regarding current knowledge about the human body, within this fictional scenario.**
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**05/28/2020 Edit:**
I did more research on each substance as well as giving them proper names. Here are those I came up with:
**• Dynar** - from latin -rupt (break) and greek dyna- (power). *Chemical given through an injection to incapacitate a meta's abilities.* (not used for this example but good to know)
**• Prooxcyte** - (substance injected directly into the subject's additional veins for the test and the cause of the subject's dangerous reaction) goes in the orange blood cell veins, reacts with the orange cells and makes the cells inflate, blocking the circulation in the veins. Subject's powers will be incapacitated, will feel emotional distress, will feel lightheaded and will start to suffocate if not treated as Subject will show symptoms of asthma as the throat will start to inflate. Subject can die of suffocation after 4 minutes. Big red marks can be found on her skin because of that, and the subject will feel numb in these areas.
**• Antioxyte:** anti- (against) ox- (growth) cyte (cell) *Reacts with the subject's orange cells to make them revert back to their original size.*
*Treatment:* Immediately put a breathing mask on the subject's face to facilitate breathing and avoid suffocation. Subject is to be injected **antioxcyte** which will revert the cells back in their original size. Immediately put the subject under dialysis to remove the substance out of her body. (Thanks to everyone who answered my question with different treatments, I selected those that seemed the best suited to heal the subject.)
I will also provide a better description of how Astrid's powers affects her body and how her anatomy is made for her to handle these powers:
**Telekinesis:** This is her main power. She is able to make objects levitate in the air just by looking at them. There are two variants of her powers. When using her eyes, she has more precision but less strength, so it is good for aiming but not for carrying heavy objects. Using her hands is the opposite, gives strength but not precision.
**Basic Mind-Manipulation/Persuasion:** When making eye contact with someone, she is easily able to persuade that person to do what she wants. This power works as a tool to convince and win arguments - she does not actually manipulate the person's brain so that she can make them move however she wants.
**Her markings and why they're important:** She has four red oval-shaped markings under her eyes, and the same markings on each one of her fingers. They glow when she uses her powers. Her red eyes also glow when she uses her powers. But moreover, these markings and eyes glow as well when she feels strong emotions. Astrid weirdly either doesn't show any emotions, or shows intense emotions where she glows. To make it short, she glows when she feels emotions. An orange substance exclusive to Astrid is located in these markings, but also in the rest of her body. This substance is spread across her body in additional veins and this is what makes her powers travel throughout her body, as well as pick up on her emotions and make her glow. The areas with the most of that substance are situated in her markings, eyes, and her brain, as her powers are mainly coming from her brain and high IQ. This orange substance glows but the glow is only visible in her eyes and markings, as the rest of the glow is hidden under her skin, although it can sometimes be faintly visible in total darkness.
**Blood/Orange Substance:** Her blood is not exactly the same as humans therefore she cannot receive blood from other humans. She must receive blood from another meta-human who has the same blood type as her. She is the only known meta with such an orange substance running inside her body, therefore they cannot take that substance from anyone else. Her parents were killed as she was taken into the lab, so they cannot use her parents in any way.
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> With this new information, I hope it will make it easier for you to
> answer. I apologize if some more scientifically precise details are
> missing, such as the molecular constitution of these chemicals. I do
> not have enough scientific knowledge as of now to provide more
> detailed information. **I named these chemicals after Latin and Greek
> words used in medicine based on the chemical's function so let me know
> if the chemicals I created actually work or if they should be named
> differently or if I should make their purpose different.** Thanks!
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[Answer]
**Bloodletting and transfusion**
Hopefully, it won't even get to that. It's what the [liver](https://en.wikipedia.org/wiki/Liver) is for, after all. In general, any foreign contaminant to your blood is removed by either the kidneys or the liver, though mostly it's the liver. Any kind of poison inserted into someone's blood will eventually be processed by the liver. If the subject isn't in immediate danger, then the best thing to do is to let the body naturally filter the toxin out. This has the added advantage of training the body in how to deal with this chemical, allowing you to slowly build up the subject's tolerance to it so you can use more tests.
If the subject is subjected to extreme distress, then, depending on the nature of the chemical, it's possible to filter the subjects blood using a dialysis machine of some kind. However, if this is an emergency, they may not have one on hand and furthermore, depending on the exact nature of the chemical and given that the subject already has unique chemicals within their blood, it may be impossible without prior tests to filter only the one you want, and you may end up doing more harm than good.
This might sound weird then, but the solution under these circumstance is straight up [bloodletting](https://en.wikipedia.org/wiki/Bloodletting#Controversy_and_use_into_the_20th_century), similar to a case of hemochromatosis. Allow the patient to bleed to remove the excess poison, and then give them a transfusion of healthy blood. Obviously, for best results, you'll want to use as similar blood as possible, not just from the right blood type, and preferably blood from a meta as well. Parents/siblings would be ideal for this. They *did* kidnap all the closest family to the subject, didn't they? I mean, that's just standard evil scientist protocol, kidnap the family in the event you need an emergency blood transfusion and/or organ donations.
[Answer]
There's three main ways we remove things from blood.
1) Supportive care so the body's natural systems can handle it. So, proper hydration and electrolyte balance, cardiopulmonary support if necessary to make sure the kidneys and liver get enough oxygen, and in some cases there are medicines that target specific contaminants.
2) Dialysis. The same thing they do for people with kidney failure. Dialysis can be done for years, but it's somewhat dangerous.
3) Whole blood replacement. This involves removing the patient's contaminated blood and replacing it with clean blood via transfusion. This is probably the quickest method, but transfusions can be dangerous.
[Answer]
If the chemical is carried by blood, a dialysis machine is a simple but effective possibility, assuming the chemical *can* be filtered.
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> dialysis, usually refers to hemodialysis: A medical procedure to remove fluid and waste products from the blood and to correct electrolyte imbalances. This is accomplished using a machine and a dialyzer, also referred to as an "artificial kidney." (<https://www.rxlist.com/script/main/art.asp?articlekey=11433>)
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If the chemical is metal-based, it may be combined with chelation, where another substance is injected so it can bind to the metal in the blood, thus allow it to be filtered by kidney, and either secreted via urine or removed by dialysis.
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> chelation (medical): a method of removing certain heavy metals from the bloodstream, used especially in treating lead or mercury poisoning. (<https://www.dictionary.com/browse/chelation>)
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[Answer]
"removed [or neutralized]" - *'Push [Narcan](https://en.wikipedia.org/wiki/Naloxone)!'*
Commonly heard on medical drama TV shows when the patient is overdosing on opioids, which is its real world use. You'll have to invent whatever neutralizes 'midichlorians'.
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Shortness of breath is usually at the highest level of concern during [triage](https://en.wikipedia.org/wiki/Triage).
In Singapore it's a *Priority Level 1* (P1). In the UK it's *Priority 1*. In the US it's *Immediate - Severe*, colloquially 'code red'.
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> If the oxygen supply is interrupted, the functioning of the brain is immediately disturbed, and irreversible damage can quickly follow. Consciousness can be lost within 15 seconds, and damage to the brain begins after about four minutes without oxygen.
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> – *Hypoxic brain injury*, PDF, [headway.org.uk](https://www.headway.org.uk/media/2804/hypoxic-brain-injury-factsheet-ad-resize.pdf)
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I don't think you'll have time for any other option than a fast acting drug, as I would think receiving the benefits of a dialysis treatment, or even to start a transfusion takes more than four minutes. [citation needed]
Naloxone (Narcan) begins its effect within two minutes when given intravenously, or within five minutes when injected into a muscle of appropriate size and location. Depending on severity, even that's often too late.
[Answer]
### 1. Magnetic / Electric effects
Dialysis is a slow process. It would be critical to **neutralise the prooxcyte quickly.**
Under a magnetic field, tiny particles can clump together:
[](https://i.stack.imgur.com/R9Ctnm.jpg)
Under electric current, chemical reactions can occur (like during electrolysis or the charging of a car battery.) This happens in addition to the obvious stimulation of nerves and muscles during electrical stimulation.
Either of these effects could result in the neutralisation of the prooxcyte. Various things could happen next, from dialysis, to natural filtration, to inert particles.
### 2. "Sacrificial" implant
Ships use a ["sacrificial anode"](https://en.wikipedia.org/wiki/Galvanic_anode) to prevent corrosion on their hulls. It is a piece of metal that gets corroded instead of the hull.
[](https://i.stack.imgur.com/YEXBsm.jpg)
It doesn't have to work on the same chemical principle, but you could have some material that the prooxcyte will react with, resulting in a deposit on the material. Just do some quick surgery (ideally get it into a major artery), and let the substance react with it. Then remove it. It could be on a flexible plastic sheet or tube or some such.
The key here is that since it is a physical object it can be removed quickly when the procedure is complete.
### 3. siRNA
Is the prooxcyte itself [siRNA](https://en.wikipedia.org/wiki/Small_interfering_RNA), and then you inject siRNAiRNA [sic] to neutralise it? Hmmm...
[Answer]
If you have people with telekinetic powers, get one of them to locate and extract the material from her body that way.
TBH, if you're going to throw in things like 'unknown radiation' then science isn't really an issue.
[Answer]
Some times you can't eliminate a chemical from the body: you have to let the body eliminate it, usually through the liver (that's what the liver does: it modifies many substances into forms that are usable elsewhere, including the kidneys where their metabolites can be excreted).
If that's the case, and it's fairly common, you just need to treat the symptoms until the liver can do its job. The biggest worry is hypoxia, or not enough oxygen getting to the brain. That's usually caused by a drop in blood pressure. Short term treatment is something like naloxone, epinephrine, or similar. Maybe mechanical ventilation.
Another problem is acid/base balance in the blood or ionic imbalances. This causes things like the potassium balance to go off, which suppresses nerve impulses and that means things like, well, heartbeats stop. Countering that usually means intravenous bags with buffered solutions being pumped in containing various salts.
Some times you can replace one bad chemical with another less harmful one. For example, the treatment for methanol poisoning is intravenous ethanol. Yes, every party-hearty frat boy's dream: mainlining the hooch. Turns out ethanol will bind preferentially to the same sites methanol would, so if you get drunk fast enough it will stop you from going blind or dying from methanol poisoning. Do not attempt to verify this at home kids.
Once she's past the first hurdles, of course, there's always long-term liver and kidney damage to worry about.
[Answer]
You're going about this the wrong way. There's no reason to remove the substance from the body. Simply deactivate it.
Most medications administered in a medical setting, especially the dangerous ones, have some group of medications that can be administered to counter the effects of the former. Too much caffeine? Try a central nervous system depressant. Too much blood thinners? Try injecting [Vitamin K](https://en.wikipedia.org/wiki/Vitamin_K), though admittedly the strategy changes depending on the blood thinner. Too much insulin? Try glucose. Too much glucose? Try insulin.
Very rarely is it actually necessary to remove something from the body. Far more common is to administer a second substance which neutralizes it.
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[Question]
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I’m a wealthy billionaire dying of terminal illness. The world I’m currently living in is clearly on the brink of a world ending nuclear war. I predict that the world ends next month. I am putting together a large “time capsule” of sorts, for future people in the post-apocalyptic world to use to rebuild.
I am able to use 5 billion dollars on my little project. My question is, what would be the most valuable tools/information to stock my Time Capsule with? The purpose of it is to help people reduced to about 1890s style living make their way back up to modern standards of living.
By 1890s tech, I mean industrialized production is in its infancy, most people farm, infrastructure in smaller towns is lacking, and no motorized transportation.
[Answer]
As a matter of fact, I suggest in this case reading a story: [Earth Abides by George R Stewart](https://en.wikipedia.org/wiki/Earth_Abides). A short synopsis of the book can be found in an [Extra Credit's talk](https://www.youtube.com/watch?v=2hieycSRUeM).
Basically, the story explores how the knowledge that made the world before the fall run - all the high technology - has become mainly obslete by the fall as it does no longer provide a benefit for the survivors in contrast to more rural and basic survival skills and knowledge.
Society after a nuclear war will be back to about a late medieval ages, at best a renaissance, level of technology, only in some pockets in the early modern age. While the knowledge might survive in the shape of libraries or time capsules, the post-fall society will not benefit from this knowledge as it is not ready for it (anymore). However, a time capsule will not be totally in vain: preserving knowledge over this dark age in some kind of time capsule will give later generations - once they are ready for it (again) - a headstart with the new-old technology.
## Contents of the time capsule
Now, what shall we put in the time capsule? First of all, it needs to be sturdy enough to survive a nuclear war and some maybe 100 years to allow society to come to terms with itself again and then another 100 to be ready to advance again. This rules out pulp-paper and microfilm for the contents but demands acid-free paper or metal engraved information in a method that can withstand the ages of time. It also has to allow deciphering the information even as the language has massively changed after these 6-8 generations. Maybe metal engraved slabs might do the trick, and writing it down in at least two, better three languages akin to the Rosetta stone might help.
One of these languages should be Math, and at least one portion of the capsule should be dedicated to mathematics, starting with the numerals and basic geometry, which allows to easily build a dictionary to transmit basic ideas.
Basic architecture (as in the design of the arch etc) should be another thing that can be easily used in the front portion of the time capsule, as it can be graphically shown and explained, making it also a good part to teach *Ye olde language*. Starting from there basic concepts of biology (Mendel) and physics (Kinematics) might follow, then spreading out into fields like practical chemistry (gunpowder) and engineering (how to cast steel)
I would advise against packing tools and instruments - a society develops always the tools it needs to survive. If it can't fabricate a tool it benefits from, it doesn't need it and is not ripe for it. It would be a waste of resources.
[Answer]
Unsurprisingly, some people have already put a lot of thought into this sort of problem, and come up with some quite neat ideas. I particularly like the [Rosetta Disk](http://rosettaproject.org/), part of the much larger [Long Now](http://longnow.org/about/) project (well worth a closer look, especially the [10000 year clock](http://longnow.org/clock/)) and a prototype of their information-preserving library idea. The Rosetta Disk in particular is intended to preserve language but the [technique](https://en.wikipedia.org/wiki/HD-Rosetta) is a general and clever one:
[](https://i.stack.imgur.com/FBfJi.jpg)
The actual data needs a decent microscope to read (which is 1800s tech, certainly), but there's a *lot* of space on that disk and the neat design around the edge encourages closer investigation and progression in microscope technology. It can be combined with an even *higher* density storage format that might need an electron microscope to read ([scanning electron microscopes](https://en.wikipedia.org/wiki/Scanning_electron_microscope) are 1940s tech, incidentally). The lowest resolution methods store 5000+ pages on a disk, both text and images. Optical reading techniques get you a maximum density of about 180000 pages per disk. Electron microscopy could get you vastly more than that. For reference, the last print edition of the *Encyclopædia Britannica* was a little shy of 33000 pages.
Etch you a whole bunch of these with different contents, and maybe provide some suitable optical equipment to get people started (or at least, simpler and more robust gear that might help them male a suitable microscope). Oh, and stash them in more than one place, to increase the chance it might be found and some idiots won't just break them.
The problem you face is that what you need to preserve is *everything*, because modern society and technology is deeply interwoven and built upon our previous discoveries and inventions and experiences that teasing any one thread out is all but futile.
My personal target would be something like antibiotics, because that leads you to generally survivable surgery which is a huge step towards improving life and lifetimes for everyone. Problem is that there's so much chemistry and biology required to build you up to that point, and so much engineering required to design the equipment to brew up the stuff, and so much metallurgy and plastics production needed to make the gear that you have to provide instructions on all that as well or you'll have accomplished nothing of use.
So, there you go. Most valuable information? *All of it*.
But don't forget to include instructions on how to read it.
[Answer]
I think the two most important pieces of knowledge to preserve are midwifery and reading/writing. And if you want to call that three things, fine.
With these two pieces of knowledge widely available to the remaining populace you can ensure that the human race can continue on and they have the capacity to learn and record and share knowledge with each other.
Human beings banged around this planet for 50K years at the same basic subsistence level of poverty. Then, 3K years ago when we learned how to read and write (doesn’t matter if it was aliens from Tau-Ceti Prime that explained it to us or if we figured it out on our own) and we rocketed to nuclear power driving Ipods and Cloud based AI overlords.
[Answer]
It's easy to say "Wikipedia" and leave it at that (no offense to that great answer), but I'll give you one specific thing that your people need or everything else is a non-starter:
## Precision machining technology (and thus precision metrology)
Precision machining techniques give you precision metrology. Without precision metrology, you really can't do much of anything that we do today: Any but the most basic kinds of aerospace (and by proxy, *anything* in space), nuclear (weapons, energy, etc), microprocessors, long-distance power transmission, utilization of RF spectrum above e.g. HF/VHF/UHF. All of these things require precision metrology, no exceptions, and you can't get precision measuring devices without the precision machining techniques. That's really the "shoulders of giants" that many of the advances of the 20th century were standing upon. Even if you did a one-off job for your calipers and micrometer (or whatever), if you expect to bring *the rest of your society* up to today's standard, you absolutely cannot reasonably expect to do this without the precision machining and metrology technology *itself* and not simply the tools. So this implies not only the mechanical engineering techniques, but also a metallurgical component. This is what allows you to mass-manufacture things with precision, such that your bearings made in Pennsylvania will fit your engine blocks forged in Detroit (and with such high precision that five hundred thousand of them can be made to fit perfectly into planes to assert your technical and industrial dominance on the rest of the world, but I digress). As a side note, Bell Labs produced a series of books about the things they made, and they are *amazing* and will assuage whatever doubts you have about the perspicuousness of this suggestion.
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In my world, there is no access to modern or traditional gunpowder. I was wondering if a dedicated technician with a modern shop (cnc machines, and a surplus of parts and raw material, etc) would be able to develop a bullet the fires from compressed air that is in the same cartridge as the projectile. Issues I am not sure of are: How big would the cartridge have to be to push a 30 caliber bullet at lethal trajectory? and how thick would the air chamber have to be to hold that pressure?
[Answer]
Combining the projectile directly with the air chamber and a single use valve *is possible*, (and exact sizing would depend on materials and valve design) but it is vastly inferior to a bulk storage tank design that is separate from your projectiles:
* Bulk tank storage means that you need 1-2 valves to fire potentially dozens of rounds at lethal velocities in place of at least one valve per shot.
* Reduced valve count translates into reduced maintenance (and potentially increased safety)
* Handling the independent projectiles does not introduce risks of damage or leaking charges.
* Bulk storage allows option for consistent regulation and reduces the risk of shot-to-shot variance due to differences in cartridge pressures.
Consider the Girandoni air rifle - each cylinder allowed approximately 30 rounds to be fired, and the soldier was typically issued two spares. The accompanying (ball) ammunition occupies a very small and highly flexible volume - This translates into ease of carrying and handling.
Contrast this to the (non-lethal) options seen in paintball and the obscure 'goblin' shells that held one paintball and an air charge to fire it:
These proved unreliable, inconsistent, and took up far more space than a CO2 cartridge beside the paintballs that could be fired with one.
And the small 12 gram CO2 cartridges weigh more and take up more space than what could be achieved with a larger bulk tank.
For handling and ergonomics, a mixed Tank+Magazine design may be what you're really after - A single bulk tank with capacity to hold a charge for multiple rounds, and a magazine of ammunition that the tank can reliably fire.
(Answer can be improved with exact numbers by myself, or another member, if needed/someone gets around to crunching the numbers - Material options and exact bullet size/weight would need to be established for accurate figures.)
[Answer]
The [Brocock Air Cartridge System](http://www.airgunmagazine.co.uk/features/10-years-after/) seems to fit your description. The cartridges are loaded with an airgun pellet and primed from a pump or diving tank. They are designed to resemble and function as close to real firearm cartridges as possible, rather than being designed for the kind of power you describe.
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I've actually designed (though not built) a cartridge that works like this. By my calculation, and by comparison to conventional precompressed air guns, I think a cartridge the size of a .30-06 round holding pressure similar to that used in PCP air guns should be able to propel a lightweight .30 caliber bullet (say, 100 grain or lighter) at close to the speed of sound, or a heavier bullet at somewhat slower velocity.
This is adequate for hunting small game (squirrels, rabbits, etc.), or marginally adequate for self defense against unarmored assailants -- ballistically, it would be similar power to a .32 ACP handgun cartridge, possibly as good as a .32 H&R Magnum (the former fires an 88 grain bullet at slightly subsonic speed; the latter fires a 100 grain bullet at supersonic muzzle velocity). It would be "single shot" in a handgun, but in a rifle sized arm could be loaded from as magazine, as was done starting in the 1890s with powder weapons.
This could be scaled up some -- a larger air capacity cartridge will give more velocity and/or propel a heavier bullet -- but there's a limit to how big it's practical to make your cartridges. If you need something like a .50 BMG cartridge to hold enough air to propel a 180 grain .35 bullet at Mach 1.5 (i.e. enough power to reliably kill deer at moderate range), the ammunition bulk is likely to limit how many rounds you can carry.
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In this story I am creating, there is an airborne infantry that specializes in disabling small ships, rapid reaponse deployment, and supporting ground forces with a large number of them. For reference they are called the Hawks.
I am a little at a loss to how a concept I came up with would work. With their fast flying and small amount of time to aim, I thought of a solution. A micro-missile rifle.
I understand that a missile has blowback, and that it's explosive yield would be a bit small if fitted into a rifle form.
You might say "why not just make a grenade launcher, or a rifle with explosive rounds?" Well what would be helpful about using Micro missiles? Would the yield be great against armor? Is it possible to strafe an entire area in a quick succession?
Would the ammunition hamper the flight capabilities of the Hawks?
Edit: The goal of the weapon, is to be able to consistently hit targets at high speeds with a minimal amount of time required to aim. Also to create a versatile weapon against aircraft, armor, and infantry. A weapon that would also enable the Hawk to still fly.
[Answer]
**Its already a thing.**
[Its called the Gyrojet.](https://en.wikipedia.org/wiki/Gyrojet)
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> The Gyrojet is a family of unique firearms developed in the 1960s named for the method of gyroscopically stabilizing its projectiles. Rather than inert bullets, Gyrojets fire small rockets called Microjets which have little recoil and do not require a heavy barrel or chamber to resist the pressure of the combustion gases. Velocity on leaving the tube was very low, but increased to around 1,250 feet per second (380 m/s) at 30 feet (9.1 m). The result is a very lightweight weapon.
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Even thought the gyrojet had issues, they would most likely be solved given serious funding:
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> Versions of the Gyrojet that were tested were inaccurate, cumbersome, slow loading, and unreliable. At best, a 1% failure rate was suggested
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The main advantages that I see with gyrojets are lightweight as mentioned above, and that they could potentially carry avionics that allow the user to guide the missiles, especially given compact modern computers. However. the gun had very little energy at close ranges and the small size of the weapon, though given that the users will be flying, close range engagements won't be very common.
[Answer]
### Make it SMART
The key is to turn an RPG or Gyrojet or other missile into a smart weapon.
* Use laser sight to pick your target.
* Location is determined based on location of the rifle combined with angle & distance (radar?) of the target.
* Press the trigger and location information is updated into missile and it is sent on its way.
This really shouldn't be much different from the way a much larger missile might be fired from a fighter jet today. The difference is miniaturization. But I think a Raspberry Pi would be powerful enough to handle the computations involved, so the only big (physical size) additions to an RPG would be some sort of additional inflight steering mechanism controlled by the onboard computer.
[Answer]
**Is your mini missile a rocket propelled grenade?**
[](https://i.stack.imgur.com/BP5hm.jpg)
<https://www.militaryfactory.com/smallarms/detail.asp?smallarms_id=10>
I envision your hawks having a quiver full of these little rockets. Sort of like the archer superheroes, not every rocket is the same. There would be shrapnel antipersonnel rockets, shaped charge antitank rockets, white phosphorus rockets etc.
How to distinguish these from generic old RPGs? I am digging the idea of rocket powered arrows. The flying archer would shoot and then the rocket turn on a second later, propelling the explosive arrow forward.
[Answer]
Using guided mini-missiles might be a good idea. There are a few considerations to take into account though.
**Flight correction time**
Rocket-propelled grenades are pretty much bullet-fast. At that speed, there isn't much time to adjust the path of the missile as you're firing in close quarters. Planes dodging missiles is actually done IRL (though not at all like is depicted in the media) and as closer ranges with less time a miss would be guaranteed.
**Backblast**
Have you heard a story from a guy who fired an RPG from inside a room? No, you haven't. When you launch an RPG or similar, there's a pressure wave from the back of the launcher called backblast, and it can kill people behind it. When you fire prone, you need to put it "sideways" across your shoulders so you don't wreck your legs.
And if fired in a confined space, the reflection of the backblast can kill the user.
**Fortunately, there's a solution for both of these problems:**
Make the micro-missiles slow. They launch out at maybe as fast as a fastball in baseball, so there's much less of an initial burst of air pressure to cause backblast, and it gives your fins more time to correct the speed. In addition, less power is needed to sustain a slower speed so that means a smaller rocket can be used.
**Weight**
This isn't too much of a concern. 25 mm grenades are a thing and your missiles, if the same size, will still pack a lethal punch. Note that you aren't going to have as many rounds as normal - the 25mm grenades for the XM25 airburst launcher came in 5-shot mags and your soldiers probably can't carry more mags than they could for other weapons with higher capacity.
**Yield and damage**
The most common idea with 25mm grenades is to use them to airburst around corners. You aren't going to get more of a yield than a grenade from these, since they'll use the same explosive as a grenade.
That said, you can specialize the payload for different targets. You can make anti-armor grenades for launchers, so your Hawks could use those against enemy armor.
As for taking out something like a helicopter, an anti-armor missile against the engine should work.
Something like a jet fighter, though... that's going to be hard simply because they're moving very fast. Good timing will be needed have the missile in the area where the plane will be, and you have to make sure that the plane doesn't just dodge. Unlikely, to say the least.
[Answer]
Given you are looking at some sort of "all aspect" missile capable of taking out ground and air targets, there is one in service which might fit the bill: the [Starstreak](https://www.army-technology.com/projects/starstreak/)
Currently in service, it is a lightweight, Mach 4, laser guided anti aircraft missile. The operator acquires the target and launches the missile. While the operator keeps the cross hairs on the target, corrections are sent to the missile via laser, making the missile essentially unjammable. Close to impact, the proximity fuse releases 3 tungsten "darts", providing a larger area coverage and virtually guaranteeing impact on the target.
Starstreak has a range of about 6000m, and has also been tested against ground targets, where the impact is similar to being struck by a 40mm cannon shell. This is likely enough to destroy or severely damage anything less than a full MBT, and will certainly damage any smaller surface vessels.
The best part about Starstreak is it is very versatile. It can be man portable, or carried on small vehicles. It is also small enough that a vehicle can carry a reasonable number of reloads inside as well.
[](https://i.stack.imgur.com/WMfcn.jpg)
*Starstreak missile*
[](https://i.stack.imgur.com/CLLkK.jpg)
*Starstreak as a MANPADS*
[](https://i.stack.imgur.com/GSGae.jpg)
*Starstreak lanched from an 8 round luncher on a British AFV. There is room for an additional 12 rounds inside*
Starstreak has been offered as a ship mounted SAM and also as a helicopter mounted AAM, so it is incredibly versatile. While the main injury mechanism is 3 hypervelocity "darts", there is no reason that the missile could not be ordered with a single unitary warhead, or an explosive warhead.
This is larger than a rifle or even shoulder launched anti tank weapon like an AT-4 or RPG-29, but this is the price for being able to accelerate to Mach 4, have a 6000m range and being virtually unjammable by conventional countermeasures. The missile is all aspect (usable against land, sea and air targets), and can also be mounted or carried by individual soldiers, vehicles, ships and aircraft (helicopters and large enough UCAVs). A star streak like weapon provides the man portable firepower for attacking hard or difficult targets.
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[Question]
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**Warning**
This question is the first of a series about specific use of teleportation. It will concern only about momemtum and speed: other subjects will be exposed later.
## Context
The story happens in our world and current era. The protagonist possesses the power of teleportation with the following characteristics:
* When teleporting, a volume including the protagonist is swapped with the same volume of matter in another place. For example, if the destination is in open air, the departure will receive the same volume of air.
* That result with no problem of collision of matter: if the
destination is in a solid rock, the protagonist will arrive in the
rock. And at the departure, there will be a volume of rock with the
same shape as the protagonist.
* There are no collision problems, but there are still problems: the
destination can override a part of something since what matters is
the volume. It’s not a problem when swapping a part of a rock, but
it’s one when swapping a part of a person.
* The volume of exchange has the same shape as the protagonist adding a
layer around it. The layer is at minima 5cm, but can expand by
willpower.
* There is no minimum time between two swaps: it can be as short as
reflexes permits.
* The protagonist can teleport as long as it has willpower: think of it
as a superhero power.
* The teleportation happens if the protagonist can picture it.
Coordinate won’t work, but a memory, a picture/film will (no matter
the distance). The protagonist could also teleport in a hidden part, even if what behind is unknown as long as the protagonist can
guess it (for example behind a door or a rock).
* Both volume exchanged keep their momentum ignoring the difference in velocity of the Earth's rotation. Falling toward Earth on the south pole, and teleporting to the north pole will result in the protagonist still falling. Flying westward and teleporting to facing eastward, will cause the protagonist to shoot forward in the eastward direction at the same speed.
* If the destination is a moving structure (vehicle...), the protagonist will teleport at the coordinate where the structure was when teleporting. But the protagonist will keep its momentum, resulting in a possible speed difference. Comparison is like trying to jump in a car in your everiday life: there won't be too much problems if the car is slow or stopped, but there will if you are on foot and the car is at 90km/h.
-If the destination is a picture or a memory of a moving structure, the destination will be at the coordinate when the picture/memory took place.
## Question
As the title said, my question is about that last point: speed.
**Are they possible downside with keeping momentum when teleporting?**
The two major problems I could find are:
* Teleporting in a moving object when motionless or vice versa.
* Teleporting by accident above a pit resulting in a free fall, which
another teleport won’t resolve (unless quick thinking).
Please try to not raise problems from other subject since there will be other questions for them.
Edit: see also the answer of Zeiss Ikon, which is a nice one.
[Answer]
From some of the comments, I believe you're wanting to discount / ignore the difference in velocity of the Earth's rotation. Beyond that, yes, you still have much to worry about.
## It's not the slide that gets you. It's the sudden stop at the end.
Deceleration for Mr. Teleporter from a **jet airplane** traveling at about 570 mph (917 kmh) to 0 at home, assuming it takes 3 inches for the body to fully decelerate, would be over 43444 G of force. That's... way beyond merely fatal. Your traveler hits the wall hard enough to go through the wall and possibly the next wall. Though he won't know, since he cannot possibly even begin survive that at all. In fact, he'll be a rather disgusting smear mixed into the debris from the wall(s). I suspect there won't be enough solid mass (bones) left over to recognize he was even human. Picture a water balloon exploding against a brick wall.
Similarly, if he's at home and suddenly wakes up, realizes he missed his flight and somehow can mentally picture the right plane (given they all look alike, that's unlikely in the extreme), he's going to suddenly appear sitting calmly in a seat that's going 570 or so mph, but he's at complete rest. I suspect the forces involved are more than sufficient to rip an entire line of seats out of their moorings to the plane's floor and even rip them out the back of the plane. Either way, your teleporter (and probably many other people) just died horrifically. But, at least its over quickly. Again, his body will be converted into a gooey mess in the initial impact between his back and the chair.
That 570 mph sudden stop translates to about 29 823 142 Newtons or 6 704 511 pounds of force on impact. That's about 7 kg of TNT in equivalent energy you've just introduced into either Mr. Teleporter's home and/or airplane.
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Maybe a less extreme example won't be so... messy?
Mr. Teleporter is in his car and realizes he forgot to grab his mug of coffee off the kitchen counter. Oops. Well, no problem. He's a commuter, but this week he's a passenger, not the drive. No one will mind if he pops back to the house, grabs his coffee, and then pops back into the car, right?
If their commute manages to get up to **70 mph** on the highway (about 113 kph), he's going to appear in the kitchen going 70 mph and have a sudden and dramatically bad (but short) day. He will slide into the kitchen counter with roughly 655 Gs of force, give or take. If he has a kitchen counter that's well made at waist height, is upper body will be torn from the lower body, to impact somewhere else downrange with much less force. So the body will be recognizable and possibly even identifiable. But the bottom half just destroyed the kitchen counter, converting it all to a messy, gooey, pulp of debris.
He strikes the kitchen with almost 450 000 Newtons of force (101 115 lb. or about 450 kJ... that's about 0.11 kg of TNT). As far as I can find via Google, it takes about 1500 lb of force to break a typical 2x4 wall stud. So at 70 mph, he's going way more than fast enough to go through a wall. But then everything gets way too messy to determine whether he retains sufficient mass or velocity to continue going through wall(s) after that.
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We can slow him down further, of course. My morning commute, on interstates, often drags along at about **25 mph** (40 kph). That same bounce-to-kitchen event results in about 83.4 G when going from 25 to 0 mph. That's still well into potentially fatal territory, but maybe his now-widowed wife won't have to completely rebuild the kitchen out of his life insurance policy funds. Maybe.
As a point of reference, the highest Gs ever survived, according to Google, is 92 G during an [Indy Car crash](https://www.news.com.au/sport/motorsport/formula-one/jules-bianchi-survived-92g-impact-in-horror-formula-one-crash/news-story/c381589f42393105511f8413c3b2fd52). [This](https://en.wikipedia.org/wiki/Kenny_Br%C3%A4ck) describes how his car hit at 214g, but his ear sensors measured 92g, resulting in multiple broken bones (femur, sternum, vertebra, and ankles). And that's with a great deal of safety equipment specifically designed to protect the driver from just this sort of thing. Your teleporter, wearing their best business-casual work clothing and without any sort of helmet, etc., isn't going to be so lucky (if you could even call an 18-month recovery from so many broken bones "lucky.") Note too that surviving high Gs requires physical training, so your typical office commuter won't make it out alive from that sudden 46 G event.
From this speed, he's going to strike with a force of about 57 370 Newtons (12 897 lb., 57 kJ, or about 14 g of TNT).
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At **15 mph** (24 kph), the impact Gs from suddenly sliding into a wall or other obstacle drop to a potentially survivable 30 G. But that's going to depend on what they hit (a wall spreads the force out more evenly, while striking a counter is probably completely fatal) and how tough they are. Regardless, they're going to suffer major, life-threatening injuries even at that relatively low speed.
Here, we've brought the impact force down to about a mere 20 653 Newtons (4 643 lb., 21 kJ or about 5 g of TNT).
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At **10 mph** (16 kph), we're down to about 13 G. That's painful but survivable, with about 9179 Newtons of impact force (2064 lb. or 2.2 g of TNT). But I wouldn't want to be going anywhere above that when I teleported.
Note, too, that if he's dumb enough to jump into the kitchen and misjudges his position, then there's now a mass from the kitchen that's sitting at rest in the car and about to strike the seat back he just left or the windshield with those same Gs, which will be destructive to the car and will likely pose a serious distraction to the driver.
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If this power is held by a significant percentage of the population, there would be laws and public service announcements and stuff to prevent idiots from doing this sort of thing...
**Teleporting with momentum is a bad idea.**
**Friends don't let friends teleport from moving vehicles.**
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A few commenters talk about surviving car crashes at higher speeds than above. I just want to mention that in a modern car, the vehicle is specifically designed with crumple zones, air bags, safety restraints, and numerous other safety features. All of this means that, in the split-second timing of the crash, the driver experiences far fewer Gs of force than the total potential Gs of two vehicles colliding. Unless your teleporter has the forethought to wrap themselves in [bubble wrap](https://www.youtube.com/watch?v=1p3kPSNiP3k) (do NOT try this at home), they won't get the benefit of deceleration until their front half collides with the wall or counter. They instead get to let their internal organs and skeletal system absorb all of that energy all at once.
[Answer]
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> Both volume exchanged keep their respective velocity relative to Earth.
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Oh boy this is gonna be fun. Not to the teleporter though.
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> Which imply there won’t be any problem if the protagonist exchanges place between North Pole and equator
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Nope :)
You see, there is a reason why the best places to launch a rocket into space are close to the equator. You get a boost to your orbital velocity by starting from a point on Earth that is moving faster linearly, relative to the rotation axis.
Such a rotation is on the order of 460 m/s over the equator. This is proportional to the cosine of the latitude; at the very poles, this speed is zero.
What this means is that should the teleporter do their thing departing from, say, Colombia, and arriving in Nunavut... They will be causing a sonic boom, for they will be flying eastwards faster than sound. They will be undergoing aerobraking - and since the human body was not built for naked supersonic flight, they will come to rest (in peace and in pieces) a few seconds and probably a few kilometers later.
Likewise, people in Colombia will see a burning mass of melting snow moving westwards. The snow will burn for the same reason meteorites do upon atmospheric entry - it is compressing the air in front of it to absurd pressures, there is no actual combustion involved. Bystanders may also become deaf.
Due to directions and geometry, the same effect may happen if the teleporter 'ports from northern Brazil to Indonesia.
If they move along the same latitude, but say 90 degrees East (Pickle Crow, Ontario to London) they will reappear moving straight upwards at $460 \times cos(latitude) m/s$. Going 90 degrees west will cause them to splat against the ground at that speed.
Teleporting inside something means an impact against the inner wall of the cavity you create, at a potentially very high speed. Great fun indeed!
[Answer]
I see potential issues with teleporting into a location that the protagonist *doesn't know* is moving. For instance, he remembers the interior of a travel trailer -- but doesn't know it's currently being towed at highway speed. Alternatively, he might teleport *out* of a vehicle without realizing it's moving (for instance, a very steady airliner flight, on straight and level course, might easily be mistaken for standing still, if you can't see outside).
Starting at 1000 km/hr is a bad thing, if you don't know it's the case. If you do, you could (assuming you have enough "remembered" destinations) teleport somewhere outdoors that puts that velocity straight up from ground, wait for the "wind" to die to as near zero as it gets, then 'port back to ground. The same method could be used (likely with prior planning as an emergency procedure) to deal with "Oh, I'm above a pit or just outside a tall building" situations.
[Answer]
Unless the source of his powers are somehow intrinsically linked to the Earth itself, I would suggest a simple alternative to Geostationary relativity is to make it relative to the "thing" he pictured teleporting to. Since you've already established that what he pictures is where he goes, then it also stands to reason that that would be the thing he aligns to.
This would eliminate problems like getting splattered inside of a moving vehicle or what would happen if he goes to outer space. This opens up a lot of plot points you can create with his power instead of limiting him by making him helpless to deal with simple issues like a runaway car.
I think the matter displacement element of his power like the risk of accidentally cutting a person in half adds enough risk and intrigue without needing to further complicate it.
[Answer]
**Teleportation cannot pass momentum**
If momentum was passed, teleportation couldn't work. A person is never actually at rest. The world is spinning and the world is also orbiting the sun in a spinning galaxy in an expanding universe. Your momentum is constantly changing even is you are standing perfectly still.
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[Question]
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In a fantastic world known as inner space, created by Deviant artist Wingsofwrath, technology is similar to our world during the 1920s with a few twists here and there. One of these twists Is the lack of rubber for use in industry and machinery. One of the main impacts of this is that military artillery is restricted in size due to the lack of rubber for use in pneumatic and hydraulic recoil compensation systems. Now a lot of artillery pieces get around this by being recoilless but bigger applications need alternatives.
In the case of warships giant artillery is replaced by multi barrel rocket turrets which fire massive salvos of artillery rockets at enemy vessels. This can be demonstrated in the two links here: <https://www.deviantart.com/wingsofwrath/art/Marbanian-Inshore-Squadron-193412682> and here:<https://www.deviantart.com/wingsofwrath/art/Tambrian-navy-193411365>. Now this concept is incredibly cool and the thought of giant naval gun caliber sized rockets being fired in rapid salvos to hit enemy ships is defiantly awe inspiring but the question on my mind is how effective would it actually be? What would be the primary advantages and disadvantages of this system in naval warfare and how might it change naval strategy?
If you would like to know more information about inner space I highly recommend you check out Wingsofwrath's DeviantArt page to discover more about his world as he has done a fantastic job of developing and creating it and I honestly could not do it justice by describing it here.
[Answer]
**Great for supporting land forces, terrible for pure naval combat**
Early modern rocket artillery weapons as seen in WW2 were area saturation weapons for supporting ground troops at the front. The key here is that the rockets were all *unguided*. On average, each individual rocket had abysmal accuracy, so they had to be fired in large quantities to compensate. The resulting bombardments are just fine for destroying soft skinned vehicles, messing up static defenses and the infantry usually manning them. However, they are pretty crap against proper tanks or combat ships; a near miss that would injure and incapacitate a foot soldier does nothing(or near enough) to such armoured vehicles. Also, remember that the concept of "suppression" in infantry combat doesn't really apply to tanks and ships.
For pure ship-on-ship combat, IMO what this concept amounts to is essentially a later and worse [carronade](https://en.wikipedia.org/wiki/Carronade) in an era where such weapons have less relevance. While massed rocket salvos may do potentially greater damage than regular naval guns, to make use of them you have to close to what is effectively knife fighting distance in the naval context while the enemy basically gets to shoot at you uncontested. Trying to fight another ship at standoff distance with unguided rockets results in a mostly harmless fireworks display
Then there's also logistics. It's fairly obvious that large salvos of rockets fired rapidly means such weapon systems consume ammo at a much faster rate than guns do. For ships who have to operate at sea for long periods without resupply, this is a significant problem. Running dry after just one or two engagements is a potentially fatal flaw. This is less of an issue for land-based artillery units who have readier access to resupply.
The reality check verdict here is basically: **dubious**. Might be considered for use as a secondary weapon on larger vessels should said navy wish to diversify their ships' capabilities, but will never fully replace regular naval guns without the invention of guidance systems for the rockets.
**Possible uses:** There are still ways to employ such weapons on ships, albeit limited. The first way I can think of is a bolt on "one shot wonder" upgrade like the [Calliope](https://upload.wikimedia.org/wikipedia/commons/thumb/3/33/T-34-rocket-launcher-France.jpg/300px-T-34-rocket-launcher-France.jpg) or the [Stuka zu fuss](https://upload.wikimedia.org/wikipedia/commons/d/d6/Bundesarchiv_Bild_101I-216-0417-09%2C_Russland%2C_schwerer_Wurfrahmen_an_Sch%C3%BCtzenpanzer.jpg). The single massive barrage these would provide would most likely be used in the opening phase of a major offensive like the Gallipoli Campaign, kicking off set piece battle(s).
The second would be launcher batteries hidden in the hull of a ship instead of tacked on and visible externally. This method would be a "gotcha" used as an ace in the hole should fighting close to spitball distance. Rockets used this way would be fired straight at the enemy rather than in a parabolic arc when used as artillery.
[Answer]
# Pro
* Range. Both the [US Army](https://en.wikipedia.org/wiki/M982_Excalibur) and [Navy](https://en.wikipedia.org/wiki/Long_Range_Land_Attack_Projectile) have extended range rocket assisted projectiles (RAP). The Army 155mm howitzer normally has a range of 22 km, but up to 30 km with the RAP. The RAP also can make some favorable shots at high elevation (i.e. the gun is pointed nearly straight up), which was a particular issue shooting over mountains in Afghanistan. The Navy's LRLAP is a much larger rocket, with a range of 150 km or more. Otherwise, the Navy's 5" gun can manage around 25 km range.
# Con
* Accuracy. Despite rockets being around for a long time (like, since the Medieval Chinese), they weren't used in Naval guns until relatively modern times. That is because extended range RAPs are very inaccurate. Launching rocket shells 25 miles away is tantamount to throwing valuable ordinance into the ocean. When they started putting rockets on naval shells, they called them guided missiles....because they were guided. The modern RAP has a GPS guidance system and flips some fin stabilizers out to ensure it gets where it is going.
* Cost. Can you believe that the Navy's new LRLAP (linked above) costs a million dollars per shot? I can't either. John McCain is dead, no one is holding the Pentagon responsible any more. Please write to your congressman.
[Answer]
**COST**
Its much cheaper to put a projectile in a tube and blast it out with explosives.
Rockets require more effort in assembly to craft the shape and motor. This can also result in a waste in size as well which further reduces cost benefits.
Now missiles on the other hand have the ability to alter their course which opens up whole new tactical capabilities.
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Rockets have a lower explosives payload than gun/bomb shells because they need to include the propulsion which is ordinarily provided by the gun. The propulsion unit is probably not reusable, making rockets expensive. Using guns should be much more economic per delivered amount of explosive or just momentum.
Using rockets potentially gives you a higher density of a single wave. That is, if you can mount all the rockets you have somehow, you can probably fire them all at once, while with a gun you are probably much more limited with your fire rate.
Rockets at this time were not guided. However rockets because of their on-board maneuvering capabilities can in principle be guided ([german V flying bomb](https://en.wikipedia.org/wiki/V-1_flying_bomb)), while bomb shells are purely ballistic.
What you would need would be conditions where the advantage of rockets (high densities of waves) is increased and the disadvantage (comparably low amount of delivered explosives) is decreased.
Decreasing the disadvantage could be achieved by **making explosives super efficient**, that is already a small amount of explosive is enough to kill the ship of the enemy.
However, wouldn't that make gun shells also much more deadly? Yes, it would. But we still have the low/high density thing.
How can a high density of a wave help? Counter measures like trying to shot down incoming shells/rockets were not invented really and would probably not work anyway at the incoming speeds and the existing technology.
A high density can help if the aiming accuracy is generally low. The aiming accuracy can be made lower if the **battle distance is large**. Make it so large that only a dense wave of super efficient rockets has a significant chance for a hit while every hit has a very high chance of killing the target.
Using guns under this circumstances is like using a sledgehammer to crack a nut. Very exhausting and not very economic and just less effective than rockets.
Maybe you could even invent a primitive guiding system for the rockets. Some kind of analogue electronic circuit logic. Simple but a bit better than purely ballistic rockets (what about strong chaotic, turbulent winds which need to be compensated).
But why should the distance be large? Well, the super efficient explosives will also help making the range longer if you use them as propellants.
**Summary: Use super efficient explosives. With super efficient explosives the one who shoots first in the right direction wins.**
Example scenario:
Two hostile fleets of rocket carriers are 200 nautical miles apart. It's very windy and rainy. They have small scout ships between them that should locate and communicate (that is actually the key here) the position of the hostile fleet as quickly as possible. The one fleet that can fire first all the rockets they have toward roughly the right position will win the battle (unless they are very unlucky). However, killing the enemy is really important otherwise he might come into range of our homeland cities and send his rockets there (and the cities locations are known, so they are an easy target).
[Answer]
Thea main reason why the Soviet's [Katyusha](https://en.wikipedia.org/wiki/Katyusha_rocket_launcher) is successful is they fired hundreds of these towards the targets position, which negates the rocket's issue regarding accuracy. But Reloading time is a pain.
Now in a naval battle, if you going to use rocket use thousands of them, and pray that they dealt critical damage to your enemy, if not, then pray that they treat you well once you surrendered.
[Answer]
Rocket vs gun is an interesting question. Apart from the very well known example of land warfare, rockets were also used in the air with one major advantage. A fighter with 24 rockets of a good caliber was lighter than the same plane with a canon able to fire the same caliber. Also, while being less accurate, these german planes were able to launch a salvo and cripple the thin armor of a bomber, and cause considerable dammages in a single row.
For me it is a use case for a small attacker, to deal dammage to a bigger yet not very well armored opponent quickly and then move. That's a weapon of choice for lights ships at close quarter range : this way they can cripple a big one on its weak point, or destroy another ship of its size. However, bigger hulls would be pretty useless when fitted with rockets. They would be easier to target, and doesn't really need the big size required to sustain bigger guns. Thus battleships would need a total design overhaul, they would probably be lighter, and used as combat platforms with the few guns your universe allow.
For me naval warfare would then be more oriented on close range combat, thus using probably more small ships (corvettes, frigates, destroyer) than medium and heavy ones (cruisers, battlecruisers or battleships). If there is no rubber I assume planes aren't an option in your world so I think there are no aircraft carriers (or no modern aircrafts). I imagine fleets would be made of hordes of small ships able to close in easily while dodging any volley of small guns the enemy would be foolish enough to fire, to be in a good position to use their close quarter batteries. All of these small ships might be supported by fast battleships, or battlecruisers, ships with slightly better armor than small ones (enough to sustain fire from rockets), loaded with short range AP guns.
I think AP rockets aren't present in your universe, as they weren't really existing in the 20's. So medium/heavy ships could carry the armor piercing shells, the ones that could engage fights at mid range, while the small ships would mostly use HE rockets to wreck havoc on other light ships / try to mess with the big guns.
Indeed rockets can deal great dammages to the deck of a ship ! As we knew ship in the 20, the crew on the deck could suffer loses while maning small caliber gun (i.e : with no armor). Thus I imagine all of your ship to be much more armored on the deck. A lot of ships deck were wooden made, I imagine with the use of deadly HE rockets that could be sent ten by ten, you'd need to protect against it, have better fire control team, hardened decks, and most likely side armor for your crew. Otherwise your sailors would die like fly in short range fights.
Last but not least, with less deadly naval guns, closing the distance would be that much easier. Which means torpedoes used as a main weapon becomes a bigger threat. With no air cover, most weapons being inaccurate, I imagine easily specialized torpedoe ships closing the distance to launch deadly torpedoes salvos. These were quite accurante, and could have a payload even bigger than naval guns shell. Also the first remotely controlled torpedoes were proof tested after the first world war, and worked (yet they were not massively deployed).
To protect against these torpedoe ships, that could be very vulnerable to HE rockets, escort ships could then carry devices similar to Hedgehog launchers : a bunch of 12/24/36 rockets to launch in a big cluster all at once, to cover a wide area in a "spray and pray" tactic, with deadly effect for small ships.
To sum up :
In terms of strategies this would mean :
* The use of swarm of ships instead of bigger and bigger ones (so no
Yamato)
* An increased need for good escort techniques and screening,
as short ranged weapons are deadlier than ever.
* A different concept of task forces, as capital vessels would be closer to screening ship
* An increased efficiency for submarines (no plane to spot them or to
use depth charges, less deadly surface weapons against their all
metal armor)
* A biggest difficulty to prepare for any naval invasion.
Think like Overlord, with water mines, torpedoes, and land artillery
firing... but ships that can't retaliate from a long range, with no
air cover to help. Well done Germany, you won this round.
In terms of design :
* More armor on the side, and the deck, less armor needed for turrets or other critical parts of a ship.
* Lighter and faster capital ship, think more like heavy cruisers (Algerie), battle cruisers (Hood, Dunkerque), than super battleship (Yamato)
* Ships with absolutely no AA, so more space to fit more weapons ! Weapons that are by the way less heavy thus making it easier to have a quicker and better armored ship.
* Torpedoes for everyone ! Battleships had torpedoes, but didn't make extensiv use of these. In this setting, they could use it.
* More interest to use torpedoe bulge for ships.
* Faster development of bigger torpedoes, and perhaps sea mines too, as these are now the biggest threat for a ship
There are a lot of other changes, in technology that I can't cover here ! But I think sonar, and radar would be that much important, as much as developping new propellants (so better developpment in chemistry and industry in general) while alloy production would be that less usefull. There are a lot of things on which you could write and imagine.
[Answer]
The other answers here assume they're taking rockets designed for launched from land, to land; and planting them on ships. In this case, the rockets are launched up to avoid obstacles, and then have to drop their altitude to hit their target.
This clearly has an issue with accuracy, but if you know you're going to be targeting things on the sea, then you'll use a different projectile path. That's just the way engineering works - if you can make a small edit to something existing to make it better in a different environment - you make that edit.
Looking at a modern anti-ship missile, the exorcist missile is one that cruises at 50ft or so... which means it can take a very shallow decline towards the water, allowing it to hit a much larger section of the ship than if it was approaching from 500ft. (It's also guided, which helps).
With a redesign of the rockets, you may be able to have them skim across the water; essentially like a speedboat. This would make them comparable to torpedoes (or speedboats with bombs on - still used largely by terrorists today); and something that in the 1920's would really be something you wouldn't want to see heading towards your ship.
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[Question]
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So not trying to wander into flat earth theory here, But a hidden fantasy world (of elves) in the present day. How would we explain it. There is no contact whatsoever between the two world. Could there be some explanation having a tiny grain of reality / science/ logic in it without driving the whole thing into "on an alternative earth".
[Answer]
Deep oceans are not very well explored, it is possible that a relatively a few small cities can be there without human knowledge.
You will need them to deliberately avoid exploration, and you need to eliminate accidental discovery.
To keep them from exploring, have religion (e.g. they were abused by surface dwellers in the past), or some survival constraint: UV rays hurt them, they have to stay near vents that provide them with some essential nutrient.
It would help if they are in the deep ocean, so they are far from shores, and cannot be accidentally discovered by fishermen or divers.
You also want both their bodies and their artifacts to sink to the bottom rather than float up. Giant squid were discovered mainly b/c they float up when they die.
In fact, make their materials and technology biologic in nature, so they rot soon after being discarded. This way you cannot have a stray fish swallow some broken or loose piece, and later turn up in a fisherman's net.
[Answer]
Before the flat earthers rose into the general consciousness, the crackpot theory of the day was the [Hollow Earth](https://en.wikipedia.org/wiki/Hollow_Earth).
This particular theory was suggested by the otherwise laudable [Edmund Halley](https://en.wikipedia.org/wiki/Edmond_Halley) in the 17th Century and lasted around 100 years before being comprehensively disproven in the late 18th Century. It then lasted in pseudoscience well into the 19th Century.
Religion has long postulated the presence of hot underworlds where souls go after death. Halley formalised this into the concept of concentric shells separated by atmosphere.
This would leave you with plenty of space for a hidden land of the Elves beneath ours, along with notable historic references for people suggesting it was true.
[Answer]
An extinct volcano.
During an Ice Age millions of years ago a volcano formed in the middle of the ocean and spewed billions of tons of lava along its flanks and which made its base very broad with a shallow angle. Over time the crust moved and access to the magma was blocked. The lava tubes though remained and created a vast underground cave. The [ice receded causing the oceans to rise more than a hundred meters](https://noc.ac.uk/news/global-sea-level-rise-end-last-ice-age) and cover all but the top of the volcano's peak which was about a mile wide. This peak allowed sun, rain, spores, seeds, insects, etc. inside the cave which began to support life.
A group of elves ventured away from their island to see what else the world offered and never returned home. They stumbled upon the remote volcano purely by accident, bringing with them domesticated livestock for eggs, milk, etc. and seeds for crops and fruit trees. They made a new home.
Meanwhile back on the main elf island a natural disaster wiped the entire colony of elves off the map (or maybe this small band of elves struck out after the disaster, or ...).
A one mile wide (or less if you chose) volcanic cone in the middle of an ocean with no other islands around would be very difficult to stumble upon if the currents and wind didn't usually go in that direction (perhaps a storm disrupted the normal currents and took the elves there.)
Take a look at [Son Doong Cave](https://www.dailymail.co.uk/news/article-2432031/Son-Doong-Cave-The-worlds-largest-cave-open-tours-Vietnam.html) which has a jungle and river inside.
[](https://i.stack.imgur.com/zsvzx.jpg)
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I'd read up about Sentinel Island and it's native population. They are believed to be a cannibalistic culture and highly isolationist. They have violently attacked any members of the outside world who had the misfortune to be stranded off their island near India. One of the few incidents with survivors details an incident where they tried to attack a rescue helicopter with spears and stones and were clearly going to kill the crew if they so much as landed.
If your hidden village is under the sea, it could easily be "Under the Bermuda Triangle" or the "Devil's Sea" (a Pacific equivalent) and have had contact that was a bit more hostile than first contacts aught to go.
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Mass migration to avoid a global disaster. The original intent may have been to return at some point but the duration of the disaster was so long that all information was lost about how to do so.
As for disasters, that could be an asteroid strike like the one that wiped out the dinosaurs, prior glaciation (global cooling), magical curse, etcetera.
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The Royal Library of Alexandria was one of the greatest library of the ancient world. However it was destroyed during the 3rd century after years of decline.
Was such a library doomed to destruction sooner or later or could it have survived, with a bit of luck, until today ?
To be clear, I am more interested in the content of the library (i.e., the papyrus scrolls) than the building in itself.
[Answer]
Depends on what you define as "survive".
There are buildings that survive centuries realively intact, even better if they are maintained over time. So there is a possibility of the walls and roofs "surviving".
As for the content, there are literally tens of thousands of clay tablets with cuneiform stored in hundreds of museums. A lot of them were once stored in the Library of Alexandria. Interestingly, the devastating fire that ultimately destroyed the library burned many of these tablets, hardening them and making them more likely to survive intact.
Most scripts were written on papyrus scrolls that would have decomposed under any less than *perfect* conditions. These conditions can only be achieved by completely sealing the papyri in an airtight container and never opening it again. Keeping content sealed is not exactly what you expect from a library, so it wouldn't have happened.
Since a papyrus scroll wouldn't stay intact forever, you would need to transcribe old scrolls onto new ones. With an estimated 40,000 to 400,000 scrolls stored in the library, you would need an army of scribes to constantly renew scrolls. Add in the fact that language and script change over time. There's the risk that a scribe simply couldn't read or understand a scroll written 300 years ago.
And then there's the content. Society, science and philosophy change over time. Transcribing a papyrus scroll is very time intense, so why would you transcribe a scroll that is hopelessly outdated if you could make your own name by writing your own book / scrolls?
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All that is presuming the society at large is very stable and wealthy and in a time of peace.
Over such a long time, there are too many warlords wanting to burn down this symbol of his enemy *just to make a statement*. A state in financial need cannot employ hundreds of scribes to transfer squiggles and lines from one scroll to another. Natural catastrophes don't stop at the front door of a library.
To sum it up, the Royal Library of Alexandria could have survived as a building, but it's content wouldn't have.
[Answer]
Other answers have focused on the building of the Great library. I will focus on the contents (scrolls, etc.) and the institution (scholars, a centre of learning, etc.). I will assume that taking measures for the preservation of the contents of the library (copying of degraded scrolls etc.) are part of its normal operation. Decay of the material as a possible threat has been discussed in [another answer by YElm](https://worldbuilding.stackexchange.com/a/122727/47889); allowing this to happen could be a consequence of the failure of the institution as a result of lack of funding, political support, or scholars.
Threats to the continued existence of the contents of the library:
* Natural disasters. Destruction of the building by an earthquake naturally threatens the contents. Directly and also indirectly since with the death of the people working there knowledge of its organization may be lost. Flooding, fire, and probably locusts may also threaten the scrolls.
* War and conquest threatens the building, its contents and even more so the institution of the library. Especially in pre-modern times, conquerors often made a point of demonstrating their power by destroying what was believed to be indestructible (such as great cities, monuments, etc) and murdering or enslaving populations. It is also possible that valuable scrolls would be removed as spoils of war (although modern conquerors would show more interest in that than ancient ones).
* Political turmoil is perhaps not quite as vicious as foreign conquest, but may still have threatened the building, the contents and the institution. The library might be viewed as a symbol of a hated regime. The scholars working there may be viewed as working for the oppressors. Either setting fire to the building or driving away the scholars may have put an end to the institution.
* Changing political attitudes. If a new religion or philosophy views ancient writings as heretical or dangerous, they may attempt to destroy the knowledge contained in those writings. Burning the scrolls, possibly killing the scholars, would be the measure of choice. For examples see the [unification of China ("burning of books and burying of scholars")](https://en.wikipedia.org/wiki/Burning_of_books_and_burying_of_scholars) and the [conversion of the Roman empire to Christianity](https://en.wikipedia.org/wiki/Book_burning#Christian_burnings).
* Economic hardship may remove the funding of the institution, possibly even the ability of the society to support this level of shared labour.
* Changing roles of the cultural institution. A library in ancient times is not the same as a library today. The library was a scholarly centre that existed on the basis of [patronage of the Ptolemies and later authorities during roman rule](https://en.wikipedia.org/wiki/History_of_libraries#Classical_period). If this role was fulfilled by a different institution (a library in another city or a completely different institution) the political support for the library would be greatly weakened, the funding may dry up.
* Random political events may lead to institutions like this one being closed down or suppressed.
The cumulative likelihood of each of these threats materializing at some point rises with time. Specifically for Alexandria in OTL:
* Natural disasters: Earthquakes in [956](https://en.wikipedia.org/wiki/Lighthouse_of_Alexandria#Destruction), [1303](https://en.wikipedia.org/wiki/1303_Crete_earthquake), 1323, etc., floods e.g. from the [365](https://en.wikipedia.org/wiki/365_Crete_earthquake#Tsunami) and [1303 Crete earthquake tsunami](https://en.wikipedia.org/wiki/1303_Crete_earthquake) and probably regular floods since Alexandria is a coastal city prone to occasional heavy rainstorms and in the Nile delta.
* Conquests in [269, 274](https://en.wikipedia.org/wiki/History_of_libraries#Classical_period), [619, 642, 645, 1365, 1519, 1798](https://en.wikipedia.org/wiki/Timeline_of_Alexandria),
* Political turmoil in [175, 415](https://en.wikipedia.org/wiki/Timeline_of_Alexandria), and then again well-documented in modern times
* Changing political attitudes from conversion to Christianity, [which actually affected the institution deeply](https://en.wikipedia.org/wiki/Destruction_of_the_Library_of_Alexandria#School_of_Theon_and_Hypatia), later rule by Muslim rulers of various degrees of piousness and again Christians in the 1800s. Especially in pre-modern times, the institution would have been at risk.
* Alexandria [declined to the size of a town of 8000 inhabitants by 1800 CE](https://en.wikipedia.org/wiki/Timeline_of_Alexandria). There is no way a town of that size would have supported the ancient library.
* Changing roles of the cultural institution follows similar lines as changing political attitudes above. With the decline of paganism, scholarship was shifted from classical academies (see e.g. the [Academy of Athens](https://en.wikipedia.org/wiki/Platonic_Academy#Neoplatonic_Academy); Theon and Hypatia's school in Alexandria had a similar role) to monasteries and was then focused on biblical scholarship little of which would have been found in the library.
I understand that this is an alternate reality question, but the series of events in OTL may serve as some guidance. All in all, I would say the chances of the library surviving over 2000 years from ancient to modern times are pretty slim. Even abstracting from that concrete example, it would be very very difficult to find an example in OTL where some institution has been mostly stable over that time span at any time in history anywhere on earth. (Perhaps the papacy in Rome gets close, but note that there was quite a bit of turmoil between 400 and 700 CE that changed the face of the city, probably also the structure of the institution of the papacy completely. Possible the rule of the Pharaoh in ancient Egypt and maybe some temple structures in Egypt and the middle East may also get close. But this may have been due to lack of technological progress and overwhelming strength of city fortifications compared to siege technology with contemporary technology.)
[Answer]
In reality, most structures in particular ancient ones, are destroyed. Some causes are well-known: dilapidation, fires or conflict - however in actual fact almost all the cases are simply that they become replaced.
What keeps them intact or replaced is the populace - constantly rebuilding buildings. In fact, perfectly preserved ancient buildings are a rarity, an exception to the rule.
Aldo Rossi, a well-regarded scholar and architect, commented on this over time in his analysis of cities. In certain instances, you can see old remnants of structures become incorporated into modern cities - not as a part of the old structure but simply as a redevelopment into a new upgraded form.
As an example here is an old Roman arena in Lucca that has been converted over millennia into apartments:
[](https://i.stack.imgur.com/59skM.jpg)
So unless the Library was significant economically or culturally, it would likely be replaced in the same manner when it was convenient. The odds are low, as it in fact it is normally forgotten buildings that ironically last.
[Answer]
Of course it could. It's a pretty simple problem, it just requires stability.
The Library of Alexandria was hardly unique, and had [a lot of competition](https://en.wikipedia.org/wiki/List_of_libraries_in_the_ancient_world#India) , even [in its own day and in its own region](https://en.wikipedia.org/wiki/Library_of_Pergamum). Most of these libraries declined along with the wealth and power of the rules/governments/societies that created them.
All you'd need to do to keep the library intact would be to alter history such that there was no decline in wealth and power. It's all about stability, really. Things like libraries get destroyed either on purpose or accidentally as a result of strife between nations. Two thousand years of history involves a LOT of authorities coming and going.
If you create an alternate history where, for whatever reason, there was a lot less warfare, where the centers of power in Egypt, Greece, and Rome never declined, or that their decline and replacement by others was more gradual and less militant, then by extension the libraries would survive also.
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[Question]
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This story set in a medieval world, where necromancy is forbidden by law, but **openly** deployed by the church to simulate hell.
There is a dedicated pool of fire just below the church of this kingdom, where criminals who are judged guilty (by the law) **are executed and animated** again and again to be tortured under various methods. Those criminals are animated with their flesh bodies and capable of suffering *both mentally and physically.* The flesh is capable of dying, of which they immediately reanimated again with new body. They are tortured under cycles of reanimation, according to their punishment, before they finally be allowed to rest eternally.
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> A murderer with mutilation may be subject to 10 cycles of continuous life of mutilation. Depending on the number victims, this may be increased indefinitely. Of course, afterward he will face other tortures if he is found guilty in other crimes.
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Basic principal laws:
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> No killing (other human)
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> No stealing
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> No lying
> No adultery
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> A bit similar to the Ten Commandments
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Small crimes
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> A shoplifter may only live 1 cycle of his hands chopped, but not executed immediately. *The punishment will be carried out when he's dead.*
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Once you die, you will always be judged by the crimes you've committed, so there's no escaping the punishment.
Other vague crimes will be judged justly by the court of the church. The enforcement is a group of inquisitors. These people are unable to go against the law.
Given that the church preaches about the **real hell**, and anyone who is skeptic is invited to come and see for themselves the hell (*anyone*), and the repercussions for breaking the law, **will this finally be the end of crime?** If not, how can we slightly alter the system to achieve that?
Let's assume that **the process is just,** and **the law itself is not corrupt.** There is no god, and there is no misjudgement. There is also no pardon. There is no afterlife.
[Answer]
Evidence of the real world shows that while overly lenient consequences can to a degree encourage crime, overly harsh punishments do very little to reduce crime. The latter has been extensively studied in the context of the controversial discussion around capital punishment. What you're proposing here is essentially just an extremely drawn out form of execution by torture, so while it's quite a bit more frightening than a lethal injection, we can still make inferences from our statistics about capital punishment - note also that other methods such as the electric chair and of course late medieval and early renaissance execution methods are relatively gruesome already.
One factor alone is that "unimaginable punishment" is indeed unimaginable. It is so far outside of our experience that we can only fear it in a relatively abstract way. Now I assume that if people can watch the poor sods in your necromantic hell this problem is alleviated to a degree, but it's still something to consider.
The more important point though is that crimes don't happen that way. Diserasta already explained that criminals usually decide on a crime when they're reasonably sure they won't be caught, so the deterrence is limited here. There's a second part to this which are crimes of passion. These are often committed in the spur of the moment without much deliberation or out of an irrational obsession. The punishment doesn't have much of a deterrent effect here either, because the perpetrator won't consider the punishment in the relevant moment. I suppose you could traumatise people so badly by showing them hell in carefully calibrated intervals that they reflexively shrink back from certain actions, but history hasn't shown this to be a thing when looking at crime rates in times where executions were gruesome and public.
Escalation is another important point that Diserasta mentioned. The reason that almost all civilised societies have defined severities of punishment reserved for proportional severities of crime is that we want to minimise crime overall. For example, even though rape is a terrible crime, it is generally punished less severely than murder. One reason for this is that if the punishment were equal or worse, the criminal would be incentivised to always murder the victim in order to get rid of a possible witness. That is why the biblical law proscribing death by stoning for the most trivial of offences and hell for the most trivial of sins is a matter of criticism in modern circles, and it is also a problem for your hell. At the point at which you're being tortured to death over and over I don't think the number of circles makes much of a difference. Chances are the victims would soon lose their minds anyway. And as Logan R. Kearsley explained, there are certainly "crimes" undeserving of death by torture for which you'd either need a whole other system of punishment or you'd lose any proportionality and semblance of justice.
So no, this wouldn't be the end of crime, nor can small alterations achieve this goal. There is a reason that today retributive justice is under question as a whole. Disincentivizing crime is definitely useful, but removing the motivations to commit it in the first place may be a necessary part of eliminating it altogether.
[Answer]
This boils down to the age old question of "can crime be eliminated"?
The short version is no. Over a long enough time scale, some poor sod will break the law, either out of ignorance or malice.
As for why someone might break the law considering the penalties are so harsh. It's a cost-benefit question. After all, you can only be punished if you are caught, and also convicted. Thus a good lawyer and/or some crafty planning will let you get away with it.
If we assume that the judges are all-knowing, mind-reading gods, and that all judgements are true and fair, then we can still fall back on the person only being convicted if caught, so they could just become a fugitive, after all the punishment doesn't get *much* worse for each subsequent crime.
A person treated like X becomes X, because there is no possible downside to doing so. The way they are treated will not change.
This is a flaw in all extreme punishments. Once you cross the line, there's no, or little harm in crossing it more.
Thus, in such a system you would have no minor crime, and the occasional murderous rampage.
EDIT:
Extra information has been provided by the creator, thus some clarification is required.
**The Church has some way of determining a corpse's crimes**
This changes a few things. Now it is an invetibality that if caught, a fugitive will be subjected to their torture/punishment (whether they are executed first or not).
In this scenario, these people have two major options:
1. Suicide in such a way the body is irretrievable
2. Flee from society
## Suicide
The only way to avoid your punishment is to commit suicide in such a way that the body is utterly destroyed, or impossible to access. Thus, when are you done with your nefarious deeds, you simply bail out on your punishment. This could be achieved by throwing yourself into a volcano (though the Church has a good 15 minutes to retrieve some piece of you), or by being intentionally consumed by a whale. If the Church doesn't have some way to track you, they'll never find the body.
## Run to the Hills
The other option is more likely if the person isn't ready to terminate their own life in exchange for their crimes. They could simply flee society. Once again, assuming the Church doesn't have some infallible way of tracking the convict, then they could escape somewhere remote, and then resurface with a new identity elsewhere in the continent, or just live in the woods forever.
This has some interesting implications in that there may be entire societies of subversive groups who were charged (wrongly or rightly) for crimes, and have not paid the price.
## Tracking
On the flip side, if the Church does have some method of infallibly tracking the convict, the only option becomes a hasty and thorough suicide, such as the aforementioned volcano option.
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In addition to the issues raised in Diserasta's answer, you have the problem that what is defined as "crime" is highly culturally dependent- and the total *amount* of it is remarkably well conserved across different cultures.
What you will end up with is effectively a "crime treadmill". As very serious crimes reduce in frequency, due to the widely publicized and excessively horrific punishments associated with them, more minor transgressions of social norms will become more and more noticeable, and consequently more stigmatized. If the crimes deserving of hellfire are "set in stone" by the religion, and incapable of being changed to keep up with social attitudes, then you'll ed up with a fairly stable society that imposes less-severe, purely secular punishments for a different set of crimes than are punished by being sent to "hell". If, however, the are *not*, and what counts as worthy of hell can change with public attitudes, then you will end up with witch hunts, where even the most minor eccentricities may be taken as evidence of heinous criminality and punished by hellfire, maintaining a roughly constant rate of admittance to "hell".
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[Question]
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It is possible for a society to live without any form of currency within our current capitalistic system?
I imagined a large city situated on the ocean that is independent from all existing nations. One could think of it as some kind of social experiment or forerunner. Its inhabitants have everything they need for living: food, water, a place to work and a place to live. Everything with a decent amount of luxury and technologically up to date. The city itself is like every other city, it has all facilities a normal city requires, although the criminality rate is *really* low.
Everything was built to be environmentally friendly and self-sustaining, at least in terms of energy and water. Cars are not used, transportation is done by environment-friendly public transportation and bike. Food is produced in form of fish, other oceanic food and small amounts of cereal products grown in hydroponic labs. Parts of the harvests and the other produces of the city are being used for trading.
So although the inhabitants of the city don't need any form of currency (except for favours between humans maybe), the city itself has a certain amount of money used for trading goods for other goods so that the city can thrive in a society that is normally driven by money.
The inhabitants are all relatively cultivated so things like vandalism are no problem. Insurances are mostly rendered unnecessary and medical care is free.
Could this system work out?
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**Short Answer**
No, not really
**Longer answer**
There will be scarcity. I can think of several things in your city that there would be a limited supply, such prime apartments, more than the current allotment of a certain type of food, construction material, access to power, works of fiction, the cooking of a chef, or the art from an artist.
Economies pop up anywhere where there is scarcity. In [prisons](http://nordic.businessinsider.com/prison-currency-wall-and-broad-podcast-2016-9/), where food, shelter, clothing, and medical care are provided free of charge, the inmates trade for a myriad of things (often using cigarettes as a means of exchange.) In [online games](https://www.forbes.com/2006/08/07/virtual-world-jobs_cx_de_0807virtualjobs.html), the coin of the game has real-world value and is exchanged for real-world goods and services.
[Economics](https://en.wikipedia.org/wiki/Economics) is the study of human behavior in producing and allocating scarce resources. Currency is just a tool. We use it as placeholders for exchanging value. Without currency, people would resort to barter. Currency makes trading easier, more flexible and faster.
Free everything would result in the [Tragedy of the Commons](http://www.investopedia.com/terms/t/tragedy-of-the-commons.asp?lgl=rira-baseline-vertical), where people use a free resource to the detriment of everyone.
Also, you have the problem with work ethic. If everything is provided for free, there is no reason to work other than for fun. Sure, some people would work for free, but ask yourself if you'd go into work if there are no consequences to staying home? If not many people work, who will operate the food and energy production facilities which undergird the society? If these facilities are not manned, the city falls apart, and nobody eats. Therefore, the rulers would have to employ some form of coercion to keep the city from plunging into chaos.
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I assume that the question is about a society which does not use money and not literally a society without a currency of its own, because the literal question is trivially true; there are numerous small states which don't have a [currency](https://en.wikipedia.org/wiki/Currency) of their own and use some other state's currency (usually U.S. dollars or Euros), not to mention the 19 member states of the [Eurozone](https://en.wikipedia.org/wiki/Eurozone). Some European countries are moving (slowly) towards phasing out the use of cash and using bank cards for all payments.
## Of course it's possible, if they like living in the Stone Age
Now, societies with no money were once the norm, up to some three thousand years ago, and here and there in remote places there are still [uncontacted tribes](https://en.wikipedia.org/wiki/Uncontacted_peoples) which don't use money. The current economic orthodoxy considers that the basic problem with a society that doesn't use money is that its economy is either extremely slow or extremely distorted.
The fundamental problem of economy is the allocation of scarce resources. Say both Mr. Aleph and Mr. Bet want to build new houses; suppose that they already have the land, and they need the bricks. Now, if there are enough bricks in stock at the brick-maker, there is no problem, they both go and get the bricks they need. But normally brick-makers don't keep stocks of bricks; so either Mr. Aleph or Mr. Bet will have to wait, or, if they don't want to wait, must import some bricks from another town, using up resources such as transport capacity and brick-making capacity. In a society which uses money the problem is easily solved by letting Mr. Aleph and Mr. Bet compare the utility of the bricks to each of them by bidding on the bricks and possibly paying more for the imported bricks; but in a society which *doesn't* use money, how can the Supreme Allocating Intelligence optimize the allocation of resources?
In Marxian terms, the *price* is the *monetary expression of value*. With no money, there is no price and there is no way to find out the true value of a brick for Mr. Aleph and for Mr. Bet. The problem of determining the allocation of resources when there is no market is what doomed the planned-economy experiments in the Soviet Union and other such places.
## But what if they don't want to live in the Stone Age
... and they absolutely don't want to use money?
There is no easy way out. As far as I know there are only two plausible solutions:
* Build a post-scarcity economy. There is an abundance of everything. (How can there be an abundance of desirable land, of servants, or of paintings by Old Masters is left as an exercise.) If there is an abundance of everything then of course that money is useless.
* Use a computer-controlled generalized barter system. I want a room for two weeks in a hotel on the beach; the company which owns the hotel wants a piece of land in the mountains; the Universal Barter Clearing Computer will find a chain of transactions, whereby I will perform 100 hours of tutoring in elementary physics for Mr. Gimel's son, Mr. Gimel will design half a dozen new dresses for Ms. Dalet, Ms. Dalet supply sixteen grosses of eggs to Ms. He, Ms. He will paint eleven motor-cars for Mr. Vav and so on, until finally Mr. and Ms. Tav will give the hotel company one fifty-fourth of their share in a desirable lot in the mountains.
Both of these solutions have dark spots, where the theory isn't yet well formed. One of those is public goods, such as infrastructure.
* There cannot be a surfeit of infrastructure, because one kind of infrastructure competes with another; for example, there cannot be at the same time an abundance of roads, of houses, and of parks; they all compete for the land.
* The generalized computer-mediated barter system has trouble allocating resources to the development of infrastructure, because the perceived utility of infrastructre is fickle. Today I want more motorways, tomorrow I may want more cycle-paths, the day after tomorrow I may want more personal public transport. Infrastructure takes time to build, and is not well-suited to point transactions.
## Rejoice, for you have ample work to do
Designing a society without money is both a perennial dream and a difficult problem. You may chose to think deeply about this society and describe it in detail; your work may become as famous as the [*Utopia*](https://en.wikipedia.org/wiki/Utopia_(book)) of Thomas Morus or as Campanella's [*City of the Sun*](https://en.wikipedia.org/wiki/The_City_of_the_Sun).
Or you may chose to go the *Star Trek* way: just assume that the society works somehow and concentrate on the story. Have you ever seen anybody use any kind of money in *Star Trek*? Only the despicable Ferengi; and, exactly as in the question, the Federation maintains some reserves of gold-pressed latinum specifically to trade with them. (See also the learned comment of @hszmv.)
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### Unique experiences
How do kids get the new Justin Bieber or Katy Perry CD?
Even if we handwave things such that they have the latest and best technology (itself questionable), we still have to explain how they avoid people trading for the things they don't have. We can even get around CDs. Maybe the government pirates them or buys them.
But how do they keep people from trading for the truly unique? Only Ariana Grande can headline an Ariana Grande concert. So unless the city has some way of hiding the entire outside world from the youth, they will want those live experiences. And of course, they need money to buy them.
### Technology
The concept of a single city that is much more advanced than the rest of the world is common in fiction, but it is not really feasible. One reason is that if it existed, it's too easy for the technology to spread out from it. But a bigger problem is that progress doesn't work that way.
One country, much less one city, doesn't dominate progress overall. There are economies of scale to production. These mean that it is much easier to locate Google and Yahoo in Silicon Valley. Or General Motors, Ford, and Chrysler in Detroit. But there are limits to production. The local universities can't specialize in both Computer Science and Mechanical Engineering. They have to pick one. So Detroit and Silicon Valley remain separate. [Michael Porter](https://en.wikipedia.org/wiki/Michael_Porter) calls these technological or business clusters.
A parallel idea is the single brilliant inventor who is equally good at computer programming, civil engineering, and pharmacology. Single people aren't even that dominant in any one field these days. Real progress is made by the interaction of large numbers of groups.
Anyway, by random variation, a good number of the brilliant people who can headline progress are going to be found in the larger population outside the one city. Unless the city has some way of pulling them away, it isn't going to be able to maintain dominance for more than a generation or two, even if we handwave achieving that dominance in the first place.
### Drugs
A significant driver of criminal activity is drugs. Addicts naturally want them. Society doesn't want people self-harming by taking inappropriate amounts. Criminals exploit that.
### Star Trek
Another answer compares this to the Star Trek economy. However, this is less plausible than Star Trek. Star Trek requires only that there be some system that obviates most kinds of work. This doesn't even allow for that. If it did, then this wouldn't be just one city. It would be the entire world.
This kind of system is not competitive with other systems. That's not really a problem in Star Trek. It's easy enough to do advanced science that a relatively small number of people can drive progress. In our world that takes a large support system. I.e. money, personnel, resources, etc.
This wouldn't be a risk-taking system. There is no benefit to risk. This will lead most people to choose the safe route. But progress is made by people looking at the one-in-a-hundred chance. Sure, it's usually wrong. But sometimes it's right. The problem here is that in an egalitarian society, the risk takers never aggregate enough resources to take real risks. It's no accident that Federal Express and Amazon.com were founded by people whose families were already rich.
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You are talking about the implausible Star Trek Federation lack of economy.
It might work out if the society was completely isolated and under strict draconian control.
The assumption is that everyone must do some minimum work to get their resources. That is because if no one had to actually work to get their resources, a large number of people would choose to not work. Then there wouldn't be anyone to generate those resources.
So, assuming everyone needs to do a minimum amount of work to get their allocated resources, there are two stagnation issues that I see:
1. **No reason to work:** Why do more than the minimum amount of work?
Why innovate better ways of doing something? Why create new ideas
that would generate more work? There is no personal incentive to
grow the society and a strong likely hood that any change will make
more work for the individual.
2. **Lack of extra goods as incentive:** What if you want more stuff than
your personal allocation offers? Currently people steal in
situations like that. Also, people trade things they need in a
black market to get things they want.
You can solve the extra goods problem by making extra goods available to people who work extra hours, perform unwanted jobs, or take critical function jobs. Are there enough of those jobs for everyone who wants one? Are there enough extra resources to pay for those? If the jobs are limited, how do you decide who gets them? Those handing out the "extra" jobs will have a lot of power.
The only way I see this working is the "human zoo" type of society. This is where one class of society controls all aspects of the other class who have no power. Historically these were called Masters and Slaves. You will probably want to choose different names for the classes to obscure the reality.
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They don't exist on the scale of cities but [communes](https://en.wikipedia.org/wiki/Commune) do exist.
The key point to their continued existence is they have to be trade value neutral with the rest of the world after including things like the exterior government. Practically this is often accomplished in part by members (or their ancestors) having been successful in the larger world before joining the commune and it might also be helped by turnover; new people bringing in more assets than leaving people take out.
Your city would need to be at least trade neutral with the rest of the world, and capable of maintaining peace with its neighbors. To do this either it must be self sufficient and poor enough that it doesn't attract military attention or rich enough that it is a valuable trading partner.
A family is typically run on these lines, with the balance of money to the outside world being important, but the work being done inside doesn't have strict accounting.
There are many criticisms of scaling this up, and most center on jerks or slackers. If there is a jerk or slacker in your community you spend effort dealing with them that could be better spent being productive either directly for self-sufficiency or to maintain your external trade balance. If you are running a surplus extra non-productive effort eats into it. If you try to remove the weak link it creates dissension or precedent which can destroy the community. Jerks and slackers seem to become more common as groups grow larger.
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You are asking "Can we build a post industrial Communist society"?
It is certainly possible, but there is a number of limitations.
First, your scenario implies that all basic necessities would be provided automatically. So, the people can do nothing and still have food to eat and place to live.
Second, there must be strong safeguards for social stability. No individual, or group of individuals can be allowed to gain power over other people. In modern capitalist society, "money is the power". While this mechanism has its drawbacks, when coupled with a strong legal system, it works. In current and former quasi-communist and socialist countries, power struggles often resulted in a downfall of the whole system.
Third, there must be some non-monetary system of remuneration. Apart from most basic needs, there are many others that can not be fully automated in foreseeable future, like healthcare and education. People must have incentive to actually do some work. Also, there would only be a limited supply of imported goods. So, we need some system of "credits" that would allow the people to buy those goods.
Forth, this society has to trade with the outer world. While this trade could be monopolized by the government, your society can not be immune to the monetary issues present in outer world, like fluctuations in the prices of commodities. You society has to sell something in order to buy something.
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Before modern currency was in widespread use there was something called Barter system in which if you needed something which somebody else had then you would give something you possess in exchange for that. It sounds simple and worked for much of human history but it had many drawbacks because of which modern monetary system became widespread. And Barter system is perhaps the closest a society can get to not using any currency and even that system was not very efficient. So in short no it is not possible to have a completely currency-free world no matter how cultivated its people are because it is simply not practical. Some form of currency system would be required and efficient one as well.
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What do you mean by money? There will always be limited resources in circulation and according to [Encyclopedia Britannica](https://www.britannica.com/topic/money), money is any commodity accepted by general consent as a medium of economic exchange, so any valuable resource traded would still count as money. Even economies that mostly worked on barter still had some form of money: [the Aztecs had cocoa beans](https://www.icco.org/faq/54-cocoa-origins/133-chocolate-use-in-early-aztec-cultures.html#:%7E:text=Cocoa%20beans%20were%20also%20used,cocoa%20had%20a%20religious%20significance.), tribes in Ethopia used (and many still use) [salt](https://www.persee.fr/doc/jafr_0037-9166_1962_num_32_2_1358), and even fictional utopians like Star Trek have items like gold plated latinum, crystals, and energy as limited resources to trade. As long as you have a limited resource to trade that others find valuable, you will have money. There will always be limitations on land and what region you can live in and unless you expect every person bidding on these locations to live together in perfect harmony & never disagree (good luck with that), there would have to be some way to decide who gets what. People would need an incentive to do jobs. So many people talk about how some would volunteer and do jobs for fun out of the goodness of their heart. While some people might do that, there is a problem with that logic:
1. [Only 25% of adults](https://nonprofitssource.com/online-giving-statistics/volunteering-statistics/#:%7E:text=Approximately%2063%20million%20Americans%20%E2%80%94%2025,time%20is%20%2424.14%20per%20hour.) currently volunteer (with volunteering meaning helping someone voluntary without pay once in a year) and only 1 out 3 adults donate at least once a year. The statistic is [about the same for teens](https://www.edweek.org/ew/articles/2018/07/18/volunteerism-declined-among-young-people.html).
2. As I pointed out [before on psychology stack exchange](https://psychology.stackexchange.com/a/25288/25157), 6.2% of adults (or about one in sixteen) have Narcissistic Personality Disorder and about 3% have Antisocial Personality Disorder. These are two of several personality disorders out there that include 'lack of empathy' as a criteria for diagnosis, so you have a decent chunk of people there that would probably not simply want to work without being given resources as compensation.
3. [Teens lack empathy](http://www.nbcnews.com/id/14738243/ns/technology_and_science-science/t/study-teenage-brain-lacks-empathy/) compared to their adult counterparts (which is why we don't give them the test for detecting sociopathy until they reach adulthood) and generally lack the frontal lobe necessary for long term decision making or controlling ones' emotions until they reach 25. Over a third of our [workforce depends on teens](https://www.cnbc.com/2019/10/06/why-so-few-teenagers-have-jobs-anymore.html#:%7E:text=Today%2C%20just%20over%20one%2Dthird,Hamilton%20Project%20and%20Brookings%20Institution.), so you would have to hope these young people with poor impulse control and less ability to care about others would be willing to do just as much, if not more, work than their adult counterparts with no incentive.
4. Many jobs, as people in the First World seem to forget, [are lethal](https://www.ajc.com/business/employment/these-are-the-most-dangerous-jobs-america/x2MOTeEYCgkt2zYCLfqfJJ/)! There is a difference between getting people to volunteer for a food drive or working a cash register without any money and expecting a logger or steel worker or crab fishermen to do a job out of the goodness of his heart that could result in their death! Some might be willing to do these jobs without incentive, but not nearly enough to sustain important industries. Many people may have a ton of empathy and compassion, but that alone won't be enough if there is a high chance of never seeing your family again for a job where many people take you for granted.
5. As someone who studies [Marxist communism](https://politics.stackexchange.com/a/53049/29927), I can let you know even that system may have money of some form. Marxist socialism tends to have people get paid resources based on a principle co-opted by Marx but originally invented by Leon Trotsky called "each according to his contribution" which was implemented in many socialist countries. Even Trotsky and Marx saw the need for incentive until the final stage of communism was reached: at which point you would still get property based on each according to his ability and need. You would still have people getting limited resources and property could count as 'money' if the limited resource was seen as valuable enough.
6. Land (or in this case, territory or spacing), energy, and other resources will still be limited, no matter how hardworking and compassionate your society is. Someone still needs to decide who gets what and many people will still want to have a lot of resources, even if they don't need such things.
Now, if we are talking about paper money, that is another story. As mentioned above, a place called [Auroville](https://en.wikipedia.org/wiki/Auroville) has only digital money administrated by an Aurocard and blockchains could be used to keep track of resources as a form of 'currency' separate from even the resource-based concept of money. A group called the Yap Tribe [used blockchains for this specific purpose](https://www.forbes.com/sites/oliversmith/2018/03/23/blockchains-secret-1000-year-history/) and let people double check resources with ledgers. With computers, you can do this on a larger scale and determine who gets what resources without traditional trading. There could also be a social credit system similar to what [China is trying to implement](https://en.wikipedia.org/wiki/Social_Credit_System).
tl;dr: Many people are not compassionate enough to want to do certain jobs without incentive beyond simply keeping society running and there will almost always be limited resources which will be considered valuable, so by the academic definition of money, getting rid of money isn't possible. However, removing paper money and traditional methods of resource exchange is still possible while providing the resource/social incentive necessary to make people still do jobs as dangerous as working at a logging mill (I know your city probably doesn't have such a job, but a self-sustaining city in the middle of the ocean with modern levels of tech will probably have similarly dangerous jobs).
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The closest real-world place I can think of is [Auroville](https://en.wikipedia.org/wiki/Auroville). There is no effectively no money and no government. It's a pretty interesting social experiment, running for nearly 50 years now, but it's not problem-free. Worth reading up on.
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# Yes, of course.
Think of your family. Does your mother pay your father to cut the grass? Does your father pay your mother to have sex with him? Do you give your kids money to lay the table? Do the kids pay the mother to cook dinner or drive them to school? Do you pay your husband or wife to listen to you when you tell them of your day?
Sure, some parents give their kids money when they do household chores, but in most families people cooperate without payment.
Where I live, even villages work that way to some extent. When someone wants to build a house, everyone gets together to build it. And they don't count hours and expect an equal return. It is just what you do, because everyone understands that they are dependent on each other. You can see this generous cooperation everywhere in this world when a disaster strikes. Suddenly it does not matter that time and things usually cost money, and people can create "goods" (material to build a dam) and "services" (the manpower to build it) seemingly out of nowhere.
Many "primitive" tribes live on that principle all the time, where the whole community takes care of the whole community. They hunt together. They farm together. They build together.
And a whole nation or world can work that way, too.
Just think of our (industrial) society without money. Not possible, you say? You are wrong. Goods and services do not simply disappear, if you take away the money that we use to pay for them. Money is a circular thing. You work and produce things that others need to earn the money to buy the things you need. If you delete the money, you can still work to produce the things others need, and they can still work to produce what you need. All you have to do is to keep on doing what you do, and despite the money gone, nothing changes.
But, you say, people won't work, if they don't have to. But of course they have to. If they aren't stupid (and people in small communites easily realize this, indepentend of their individual intelligence), they see that if they want to eat, dress, and sleep under a roof, they will have to work for their food, clothing, and housing. If you don't want to die, you will have to work.
And people actually like to work, too! People are easily bored. So they will do things. And while a few might enjoy to just lie around and watch tv, most people need to do things that give their lives meaning. People like to work in the sense that they enjoy doing meaningful things. Many middle-aged men get a depression when they lose their jobs, it is one of the most common reasons for depression in that age group. And not because they don't have any money. They do. But simply, because their live has become meaningless. And why do retired people do all that unpaid, voluntary work? Because they want to work!
So *basically*, if you took away the money, maybe people would stop creating much of the superfluous garbage that we use to drive our economy (like a tv in every room of the house or new shoes although the old ones are still good), and some of the more unpleasant things would need a bit of reward (just cleaning your own toilet is not something that all of us enjoy doing unless our new girl-friend wants to visit), but *basically* we would certainly still want, need, and create everything that makes our live worth living (from food, to clothing, to housing, to entertainment).
The only *real* changs would be that we would no longer have rich people. Because there wouldn't be anything to hoard and withhold from others.
Yes, there would still be theft and war, because there would still be people who love to take from others. But that's what I said: **basically, everything would remain the same**.
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[Question]
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The [Schwerer Gustav](https://en.wikipedia.org/wiki/Schwerer_Gustav) is one of the largest guns ever used - by many measurements, it is the largest. But it lacks range. It was, however, designed to be an extreme bunker buster, a job which it could do very well.
On the other end of the spectrum, the [Paris Gun](https://en.wikipedia.org/wiki/Paris_Gun) had an incredible range - But, being designed as a psychological weapon, it lacked power and accuracy.
What they both lacked was mobility, which severely limited their usage.
Here's where we get theoretical: Presume we have a gun that *combines the power and accuracy* of the Schwerer Gustav *with the range* of a Paris Gun. Of course, it's not as powerful as the Gustav, and it doesn't have the entire range of the Paris Gun, but it's both long range and heavy hitting.
Now, we're on a world with WWII-level warship and metalworking technology. The order goes out: We want one of these guns put on a ship, to be able to sail around the coasts of our enemies and be capable of bombarding inland targets. The requirements:
1. The ship only requires one of these Bombardment Cannons.
2. The Bombardment Cannon must be able to traverse independent of the ship, as much as possible without compromising the ship or weapon.
3. The Bombardment Cannon must be able to fire while the ship is under way. While obviously not preferred, we can't always have things our way.
4. The Mounting Ship must be able to have secondary weapons for self defense. While [aircraft are not currently a large threat](https://worldbuilding.stackexchange.com/questions/73392/how-would-aircraft-and-air-life-develop-on-high-g-lower-atmosphere-planet), they are beginning to show up, so some anti-air capability is required.
So, now that we have the background and required information: What would such an "Extreme Bombardment" ship even look like, and how large would it be? I'm presuming that a turret mount is out of the question due to the sheer size of the gun, so what sort of traverse would we be able to get?
**Some Notes:** Aircraft are not developed at this time, nor are aircraft carriers. While aircraft will be superior, that fact is irrelevant. This also is not necessarily something that would be practical - More of an influential politician's "good idea" that's pushed through regardless of some better ideas.
**Some Further Notes** There have been many answers and comments that this is probably the least practical way to bombard someone. That's **entirely** the point. In-universe, it's the idea of a particularly influential *politician,* influential enough to get it designed and built. It doesn't have to be particularly effective, it just has to exist.
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# Those guns are useless
The [16" gun emplacement](https://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun) on a Iowa-class Battleship ([which is three guns, incidentally](http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php#Mount/Turret_Data)) weighs 1700 tons. Schwerer Gustav weighed 1350 tons, but was not armored. The 3 16" guns themselves only weighed 121 tons each. So you could mount about 10 16" guns in the same weight as one Schwerer.
The effective firing range of Schwerer Gustav is given as 39 km on the Wikipedia page you linked. The range of the 16"/50 is 39km. A [1987 test](http://www.navweaps.com/Weapons/WNUS_16-50_mk7.php) of the re-activated ships were able to put 14 of 15 shells within 230m of the target at 31.9 km. The [official Navy range tables](http://militarynewbie.com/wp-content/uploads/2013/11/US-Navy-16-inch-Gun-Range-Tables.pdf) at the time put the weapon's range at 35 degrees elevation to be 36,788 yards, or 33.6 km.
The existing 16" weapon had the range of the Schwerer, and could mount 10 guns to the Schwerer's one by mass. Where the Schwerer could fire a 7 ton projectile, the 16" turret could put out 10x 1.2 ton projectiles, more iron downrange. Rate of fire is also relevant, though I can't find numbers, I suspect the 16" fired faster.
If you want longer range, what is wrong with an aircraft? The [Avenger](https://en.wikipedia.org/wiki/Grumman_TBF_Avenger) had a range around 800 km, which is way more than any gun. Why maneuver your gun-ship within 100 km of the shore when you can pummel it with air raids from over the horizon; something that was repeatedly done to Japanese strongholds during WWII.
Think about it this way, WWII was a total war. Anything that could be useful for the war effort was invented and/or built (jet fighters, ballistic missiles, nuclear bombs, etc). If putting a 1350 ton, 80m gun on a ship was actually useful, someone would have done it.
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Well, there were historical ships like the British [Erebus-class](https://en.wikipedia.org/wiki/Erebus-class_monitor) monitors with [15"](https://en.wikipedia.org/wiki/BL_15_inch_Mk_I_naval_gun) guns. One could imagine a similar design with [16"](https://en.wikipedia.org/wiki/16%22/50_caliber_Mark_7_gun) or [18"](https://en.wikipedia.org/wiki/40_cm/45_Type_94_naval_gun) guns. On a slightly larger scale, there were [coast defense ships](https://en.wikipedia.org/wiki/Coastal_defence_ship) or coast defense *battle*ships, but those are probably too large for your purposes.
* The Erebus had twin 15" guns. One could envision a design with a single larger gun instead.
* A turret mount is not out of the question, but there could be limits to the *safe* arc of fire.
* For very long range fire, it is important to get a stable and well-surveyed firing platform, like the reinforced rail lines of the Schwerer Gustav.
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I tried to describe this idea a couple times, then gave up and slapped it together in paint...
[](https://i.stack.imgur.com/l1LOn.png)
Join two large battleships together at the bow and the port to form a giant catamaran. Then hang the supergun in between on a single axis gear which allows it to fire straight ahead at a variety of ballistic angles, plus fire straight behind, also at a range of angles.
integrate bullpup concussion absorption into the barrel and gear assembly so that the gun doesn't break the spines of both boats during its first use. You might also be able to spread the kickback out in the water beneath the boat since the shell chamber sits under the surface at most firing angles.
Since the supergun hangs between the two hulls, the decks are available for defensive and anti-aircraft weapons. The turreted guns should also be bullpup and perhaps scaled down a bit to keep their recoil from breaking the structural elements which unite the ships. Either that or put hinges on the cross-members so that they can bend whenever the hulls buck during turret fire.
It might be a good idea to keep each battleship whole and operational, with separate bridge, radio and engineering sections. This redundancy would help the ship absorb battle damage while remaining combat capable. It would also allow the healthier hull to blast itself free (from the gun and the crippled hull) to serve as a lifeboat/escape craft for both crews in a worst case scenario.
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By WW2 technology had progressed to where very large guns were no longer considered the way to go, so by your own statement that that's the level of technology your ship would be obsolete by the time it was launched.
For shore bombardment, a larger number of smaller guns, possibly in combination with rockets and/or aircraft is far more effective.
Larger spread of fire per salvo if you so wish, shorter reload times (thus higher fire volume on target), more stable (and thus more accurate), easier to transport (smaller ships, or same size ships with more guns), and losing one ship is less likely to cost you the bulk or all of your firepower.
As said in the other answers already, the stability of a ship as a firing platform for something this massive is highly questionable to put it mildly, another reason shipboard cannon peaked at the 18" mounted on the Japanese Yamato class battleships, and at 15-16" for other navies.
Another major problem for a weapon that big is that the barrel of the gun only lasts a very limited number of shots, and replacing the barrel while underway is next to impossible.
After a few days of firing (at a rate of 1-2 shots per hour) your ship is useless unless it were as a command ship or for its secondary batteries and sensors, just a big inviting target for enemy forces.
Not only do the barrels of smaller guns last longer, they're also easier to replace (whether that was ever attempted at sea with main battery guns I don't know, most likely they were replaced regularly during port visits).
Another point not mentioned yet is that the weapon, in order to have both the shell weight of the Gustav AND the range of the Paris gun, would have to be humongous. Just adding a longer barrel to the Gustav (which was a mortar btw) wouldn't do it. You need a lot more steel, making the barrel extremely thick (and thus heavy) in order to contain the propellant gasses from the massive charge (several times larger than the charge used in the Gustav OR the Paris gun).
And to elevate that massive weight you need far larger mechanisms as well.
End result is a weapon of utterly impractical dimensions, a weapon that's probably too large to fit on any ship envisioned in WW2 or since.
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> Now, we're on a world with WWII-level warship and metalworking technology. The order goes out: We want one of these guns put on a ship
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Then the engineer comes in and says: Herr Oberleutnant, have you considered, you know, rockets? It's 1942, we have build them and called them V1 and have plans for V2.
The forfeit in usage of such guns was that
1. they have very strict usage. You can cover the belt 150 km from the coastline but only in reduced line. So if your ship have a radius of fire 150 km but only 45 degrees how fast he can move 300 km further the coast. It can be used on finished amount of target. After they are conquered the ship and it's gun is useless.
2. The problem with artillery (which is mentioned in linked wiki page) is that the barrel get worn-out. So in you usage you are not only limited by the projectile per time but also the time when the whole ship is out of service because the barrel need to be refitted
3. It's mobility. you have one ship with one gun that can go 25 knots (38 km/h). Versus, let say 20 Katyusha with speed 60km/h. So katyusha can fastly go to the coast and flood you with rockets. Of course you can have your ship far away from their range but it will also decrease your range.
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I think to get an idea of what your asking you need to look at the wooden sail ships and how they handled cannons.
There were (and still is) always three main problems. Weight, recoil, and maintainability.
**Weight** Ships can not handle an unlimited amount of weight. The more weight you have the lower the hull sits in the water. The lower in the water you are the slower you can turn or move. The more fuel (or sails) you had to use to move you, which means more weight. With sail boats it means more sails, a stronger rigging and mast(s), etc. Today it means more fuel and larger engines. Keep in mind that weight needs to include ammo, tools, men, and food to fire the gun, along with the gun it's self. Lets not forget balance. You can't hang a large weight over the side of a ship without it tipping.
**Recoil** Back when wooden sail boats were used, cannons generally just "pushed back". Some on tracks or grooves, but many just "back". This was great as they allowed for easier reload, but too big a cannon or to big a shot and the cannon would "push back" right out the other side of the ship. A little forward in time and we started hard mounting guns so that couldn't happen, but that just destroyed the ships, so we went with compensators and the like to "absorb" the excess energy (this isn't really correct it's more like redirect) But gun size was and still is limited by this factor.
**Maintainability** Again lets look at the era of wooden sail ships. People died. as a matter of fact when fighting with things that go boom people die. You can't have your super gun workable by just one person or when he dies it's all over. Same is true for maintenance, cleaning, loading, aiming, etc. You will effectively need a team of people that can die to man this gun. The same is true today. Super weapons exist, but there not fitted for use in combat because the average sailor can't figure out how to use it. For example that the WWII era guns. With little training anyone could be thought to load, aim, and fire those guns. Maintenance was a bit more difficult, but a ship had several persons that could do maintenance. Today we have rail guns, lasers, plasma cannons, and a whole bunch of fun sounding weapons that look good in demonstrations, but are just plain to complex to use when someone is shooting at you. You need to make sure your weapon is actually usable, without any "special" skills.
**Possible Solution**
As were on world building and not really looking for "the best scientific" answer, then I suggest that your BFG be place inside the hull of the ship. Build the ship around the gun, think Death Star but V-Shaped. Firing the gun would cause some serious side effects, and aiming means turning the boat not the gun, but that has been done before.
The deck can be used for small arms and anti-air, but is largely empty.
When the cannon is fired you need to clear the sounding areas. Fire. Then the recoil can be absorbed by the water. The entire boat would "jolt" like a plastic toy boat in a tub, so everyone should strap in. There would be some pretty hard limits to the number of times you could fire, and the boat could be used to turn fast, but move forward slowly. Gasses and maybe even plasma from the firing could be used to some effect, but would likely need to be flushed out somehow. Maybe by pushing against the water, helping to reduce the "bounce".
After just a few firings though (say 5 for arguments sake) it's time to head back to port an refit some parts. After 100 or so firings it's time to scrap the ship (though the gun can probably be salvaged).
Seems like the makings of an interesting chapter or two to me.
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Considering how such a large mass installed above the water line would unbalance a ship, and how the recoil of the shot would need a well balanced ship to avoid flipping it over at the first shot, I think a reasonable choiche would be to install it on a submarine, using the entire submarine body as casing for the cannon.
When you need to fire, you manouver to align with the target, lift the cannon out at the needed angle, fire one or more shells and take cover again.
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It has already been mentioned several times that this would be a totally impractical project. That is a correct assessment, but it doesn't actually answer your question. Baring that in mind, let's talk battleships.
The largest ship-mounted gun during WW2 was the [18.1" Type 94](https://en.wikipedia.org/wiki/40_cm/45_Type_94_naval_gun), which was mounted on [Yamato-Class](https://en.wikipedia.org/wiki/Yamato-class_battleship) Battleships. Notably, the Yamato-Class was itself the heaviest class of battleship ever built and for a variety of reasons was totally impractical because of it. However, I would contend that it's guns were not among those reasons. The 18.1" had a maximum range of ~45KM and a rate of fire comparable to the 16" guns used by the American Navy.
A single Yamato-class had 9 of these guns, the total weight of which would be comparable to a single Schwerer Gustav. You could therefore possibly mount a single gun of this caliber on a Yamato-Class ship, or on a fictional battleship of similar size. If the weight of this fictional gun was closer to the Paris Gun, then you could even mount 2 or 3 of them. This would leave room for secondaries and possibly for backup barrels, though at 7 tonnes per shot, I would expect the ship to run out of ammo before it ruined its barrel beyond "usefulness".
Looking through your requirements, I'm not sure what you mean by the cannon being able to move independently of the ship. If you mean that the weapon can detach from the ship, then I have good news and bad news. The good news is that the requirements for carrying the thing got a lot easier, as any sufficiently large barge should suffice. The bad news is that there is absolutely no way that this thing is firing while on-ship. Moving on, I will continue under the assumption that this bombardment cannon is mounted to the ship, rather than carried by it.
Firing while moving is tricky. This cannon would need to have enough muzzle power that I would be worried about the long-term integrity of the ship's hull. I suspect it's not particularly accurate in the first place due to the mass of its ammunition, but any accuracy it has would likely be lost while moving. Moreover, I'm concerned about the effect that firing this gun could have on the ship itself. Let's run some quick napkin math here.
The shell of the Schwerer Gustav weighs 7 tonnes or 7000KG. It has a Barrel which is 30M long and a Muzzle velocity of 720m/s (with AP Rounds). With these numbers, my conservative estimate of the force involved is 60480KN (The actual number is likely quite a lot larger). This equates to a change in velocity for the Yamato-class ship of 70m/s or 19.4KM/h! I'm not sure if that's enough to flip the ship, but it's almost certainly enough to do unpleasant things to the hull while it's sitting still, much less when it's moving. I'm sure there existed techniques to help absorb recoil on ship, but I'm unfamiliar with it as a topic and frankly doubt that it's up to the task of fully mitigating this behemoth.
(I am not a physicist, so please correct me if my numbers are exceptionally bad. That said, please also bear in mind that this is an estimation.)
Finally, I do have a small bright side in all this. As we only removed the primaries to mount this monstrosity, this ship will have just as much Anit-Air capabilities as any other Yamato-class. Sure, 2 of the 3 Yamato-class ships that were built were sunk by air-attacks, but hey, it's better than nothing.
Don't go claiming that anything containing this thing is "realistic", but I've definitely seen more outrageous weapons in fiction.
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While what you are asking for is somewhat impractical with WWII era technology, the modern USN is actually looking at getting "guns" to have similar performance metrics for near future warships.
Experiments are ongoing with electromagnetic rail guns, and the ultimate aim is to arm large warships (comparable to 10,000 tone cruisers) with batteries of 64Mj railguns. The projectile could have a range of 200km, actually exiting the Earth's atmosphere for part of the trajectory and descending to the target at Mach 6, causing destruction through kinetic energy alone.
While there are still lots of technical issues to be solved before railguns can become part of a ship's arsenal, engineers noted that the extreme aerodynamic shape of a railgun projectile could be adapted to current artillery pieces. The shell can be fired with a large charge and effectively double the range of the shell, or since the shell is flying far faster than a conventional shell of the same calibre, it can also be used at close range firing with a very flat trajectory at incoming missies.
To give you an idea of how this might work in practice, a 155mm artillery piece can fire at a range of @ 30 km. Rocket boosted and "base bleed" shells can extend the range somewhat, but with a general loss of payload and accuracy. Experiments using the new form factor suggest that a range of 70km can be expected with "normal" shells. Adding rocket boosters or base bleed should extend the range, although I have no knowledge of any experiments along these lines. A 155mm cannon using a boosted aerodynamic shell might be able to reach targets up to 100km away.
This actually has a historical precedent. German engineers experimenting with rockets in WWII also developed the so called "arrow shell". This was fired from a specially modified K5 28cm rail gun (in this case, a huge conventional canon mounted on an enormous railway flatcar). The range was effectively doubled to [127km](http://www.one35th.com/model/k5/k5_ammunition.htm), and the gun hidden in a railway tunnel and used to fire on the allied landing at Anzio, Italy. The gun was safe from allied fighters and bombers sent to silence her, because the search radius was set for @ 60km from the beachhead, which was considered the maximum possible range for a rail gun of that era. The downside was the Arrow shell had a very small payload, and using arrow shells eroded the barrel quite quickly compared to regular ammunition.
[](https://i.stack.imgur.com/wSLlF.jpg)
*Krupp K5 similar to "Anzio Annie"*
[](https://i.stack.imgur.com/NDawD.jpg)
*Peenemünder Pfeilgeschosse (arrow shells)*
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I would take a Yamato class battleship, strip it of the forecastle, all of its big guns, and place the Paris gun where the back turret used to be
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The bigger a gun got, the less moveable it was. The static 'super guns' such as the V4 were very vulnerable. Any hit could distort the barrel enough to make it unsafe. Barrel wear was also a problem - shells were supplied in increasing sizes to be used in order.
The range is almost unlimited. You could fire all around the world: see [Project Harp](https://en.wikipedia.org/wiki/Project_HARP)
Let's combine this with the [FLIP survey boat](https://interestingengineering.com/innovation/flip-the-60-year-old-research-platform-that-flips). This was designed for hydrographic surveys. It operated upright to give a very stable platform in a swell, but it passed stably through all angles. If we combine these two pieces of sixties technology, we could make a submarine with a giant gun along its axis. When it fired, the submarine would be driven into the water. If the gun fired from the back, the submarine would travel forwards.
I don't know of anything like this being built. But mounting a giant gun in a submarine does get around the vulnerability problems of the big guns of WW2.
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I thought of a species that acts on a hive mind. They are about the size of a 5 year old. Whenever they see a threat to their brethren (or king and queen) they explode (not like a fiery explosion). When they explode, they release a gas that can either be toxic or flammable. Are any of these things possible?
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Maybe you should take a look at the ant [Camponotus saundersi](https://en.wikipedia.org/wiki/Camponotus_saundersi) .
It self-destructs to release the toxic substances:
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> When combat takes a turn for the worse, the worker ant violently contracts its abdominal muscles to rupture its gaster at the intersegmental fold, which also bursts the mandibular glands, thereby spraying a sticky secretion in all directions from the anterior region of its head. The glue, which also has corrosive properties and functions as a chemical irritant, can entangle and immobilize all nearby victims.
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Sure. Modern honeybees seem like a proto-example of what you're talking about - stinging protects the colony, but sacrifices the individual. A true hive mind would be more difficult to arrange with known physics - unless we're okay with it being very slow, in which case the individuals composing the hive mind could effect mind-to-mind contact by a very complex system of pheromones. This seems like a natural outgrowth of the modern behaviour of a number of species of ant.
As for the explosion - nothing particularly difficult about that, in principle. For example, if the creature has a sac storing sulfuric acid and a source of fluorite internally, it could combine them to produce a large amount of hydrofluoric acid gas. A great deal of gas forming very rapidly inside a creature without particularly strong structural integrity would cause something like an explosion. Hydrofluoric gas is a toxic gas that is able to pass through skin relatively unhindered; walking through the area where such a creature exploded would not be a pleasant experience.
A similar sort of chemical reaction could produce a flammable gas instead, if you want.
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How would you form an extended stretch of coastline that is effectively useless for overwater trade -- i.e. there are no sheltered areas to serve as ports, or trade routes that can reach all the way to the shore to allow ships to trade? It seems that a coast with cliffs would be an important element of this, but what would prevent paths up and down the cliff forming, or the cliff being divided into segments (say, by estuaries) for that matter?
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### Huge waves
They erode back the land to make steep cliffs with no inlets or natural harbors, and are hostile to ships that approach the shore. The shallows will be filled with huge rocks from the formation of the cliffs.
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You could have dangerous reefs, a tricky tide with heavy waves and strong currents due to the shape and size of the reefs, just far enough off the beach to prevent trade vessels from coming near enough for practical purposes.
That way, you can still have fishing boats between the shore and the reefs, you might even have some small-scale trade, where the cargo is transported over the reef in small boats, but nothing major.
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1. Have the coast along a divergent tectonic plate boundary and you can hope to have a very long steep coastline. See the East African rift or lake Baikal in Russia if you want to have an idea. It's not exactly as steep as the cliffs of Dover but it's still very difficult to put infrastructures on it.
2. Have a strong uninterrupted wind, flowing all around the planet. Winds around Antarctica are very strong with an average speed around 30 to 40 kmph. Strong winds also tend to come with bigger waves. That's a big problem for traders.
3. Funnelling the water and the winds into a narrower water body will also speed things up.
4. The coast is steep but a lot of debris have fallen overtime, making navigation treacherous. Just having an unequal water dept with patches of shallow waters here and there could make navigation much more complicated. As an example, navigation on the St-Lawrence river requires captains specialized on that specific river because there is a lot of shallow areas, although it's not as windy as in my configuration.
5. Having a large temperature differential will make the winds even stronger. But I'm not sure it's possible to do that with that kind of configuration. Having two large landmasses close to each other might not produce that effect. But I'm thinking maybe one of the landmass could be long but thin. Supposing that the large landmass is north of the passage, the thin one is on the southern side: have a large ocean south of these two. In winter (assuming it's in the southern hemisphere) the large continent become much colder than the ocean in the south but during summer, land is also much hotter than the water. This temperature differential will help having strong winds.
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You could have a coast line with craggy mountains, numerous fiords and ice shelves of large floating rafts of ice frozen fast to the coast and extending out into the ocean. Like Ellesmere Island's northern coast, to provide an example, where it is virtually impossible to land a ship during the time of the year that the ice is present.
You could also have a coastline with long term volcanic activity, like Kilauea in Hawaii with its world famous lava flows into the ocean.
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I'd look at all sorts of coastal islands. Sea stacks, for example. There are plenty of naturally occurring islands out there that are inaccessible by boat. Typically due to: cliffs, reefs, and the sea itself (rough seas).
Cliffs make it impractical to build infrastructure for shipping, but you are correct in that people could always build trails. So I don't think it's the cliff that are necessarily the key element. Just one of the barriers. The bigger barriers would be shallow sands (possibly fixed via dredging), rocks and reefs (possibly fixed via demolition), rough seas (possible fixed by building sea walls).
All surmountable, of course, but typically highly impractical. If you look at the west coast of North America, you'll find a lot of of the coast is not easily accessible by large ships. Most ports are in fact inland (up river or within large bays).
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Cliffs are an easy answer, just make them incredibly steep descending into very deep water, with no harbor or sandbar for protection. Think of the Cliffs of Insanity from the Princess Bride. Even better make the cliffs slightly overhung to prevent path building.
But this is Worldbuilding, and we can do better. Instead of building a vertical barrier, let's build a horizontal one. Certain kinds of swamps are impassable, where there is just too much water for too little ground. Mangrove swamps are still passable by boat so that won't work. Grassland swamps like the Everglades won't work either because special boats can get through. Our swamp needs to have densely packed trees surrounded by deep, quicksand like mud. The dense trees prevent skimmer boats from working and the deep mud precludes trails or any kind of cargo capacity if someone did try to slog through.
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Fill the sea with monsters!
Anything in the sea that threatens the lives of sailors or the destruction of cargo would discourage traders from landing. People don't trade if the benefits from doing so are outweighed by the risks.
For example:
* Unpredictable storms / big waves
* Scary monsters
* Ice
* Bad chemicals or bacteria in the water
* Dangerous reefs or rocks
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A seafloor consisting of many, many rocky spires that stick up to near sea level. Obviously there can't be so many that passage is actually impossible but there are enough that it's unduly hazardous, nobody would go there other than for a dire emergency. In the calmest of times it's passable to vehicle like airboats.
As for why it's like that--there's a volcanic field underneath. It's not actually eruptive, though, but rather you get lava oozes. Something about the situation results in pillar formation rather than the usual pillow lava. This only happens underwater, any lava that pokes out of the water responds to gravity more normally and falls down. Thus the pillars top out just below the bottom of wave troughs.
This is an ongoing process, even if you mapped every pillar out there and used GPS you couldn't trust you wouldn't run into a new one. The acoustics are terrible, trying to map the pillars with mine-hunting sonar is challenging and unless you have several propulsars on your ship you can't safely hold station while you are trying to figure out where it's safe to go.
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Shallow sandbars, rocks, winds and tides going straight towards the rocks. Take a look at the San Francisco Potato Patch for an example of where you don't want ships to be.
Also, underwater methane hydrate vents are one plausible explanation for how the Bermuda Triangle got its reputation. Methane gas bubbles up, the density of the water changes, ships no longer have the buoyancy necessary to stay afloat.
<https://en.m.wikipedia.org/wiki/Bermuda_Triangle>
Alternately, perhaps the entire coastline is on fire.
The Centralia mine fire in Pennsylvania has been burning for over fifty years, and has enough fuel to burn for a few centuries. It's basically an emtire coal mine that is on fire. Gasses from the underground fire seep up to the surface in concentrations sufficient to be a hazard to life. Flames occasionally can be seen on the surface. The coal mine is about 8 miles long.
So I envision a section of coastline with modest cliffs. An underground coal seam is on fire. There are a few small natural caverns in the cliff, so some seawater occasionally comes in contact with the fire. Not enough to put it out, though. The water hits the hot coals and immediately turns into scorching steam, which then vents to the surface. So you've got carbon monoxide gas, scorching steam, and occasional flames emitting from the ground.
If that's not enough, throw in a lagoon being heated by the fire, causing a chronic red algae bloom. Give the lagoon a few outlets running down the cliffs, carrying the algae with it. Now you've got a permanently smoking, scorching landscape with flames and with cliffs that look like they're weeping blood. I think that would say Stay Away to anyone.
<https://en.m.wikipedia.org/wiki/Centralia_mine_fire>
<https://en.m.wikipedia.org/wiki/Red_tide>
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**Ice calving**, also known as glacier calving or iceberg calving, is the breaking off of chunks of ice at the edge of a glacier ...
Calving of glaciers is often accompanied by a loud cracking or booming sound before blocks of ice up to 60 metres (200 ft) high break loose and crash into the water. The entry of the ice into the water causes large, and often hazardous waves. **The waves formed in locations like Johns Hopkins Glacier can be so large that boats cannot approach closer than 3 kilometres** (1.9 mi).
The above is from the Wikipedia entry on Ice Calving.
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Once again, I am asking questions based on my as of yet defined highly-evolved, human-derived "merfolk". But this time, I'm going towards deeper waters-- let's say about 5000 meters below sea level for now. My "merfolk"'s rough average technological level is roughly analogous to a 1950s-60s Eastern-European/Greek working class towns (I think, it's hard to find a specific equivalent time period for now); with a dash of just enough sci-fi to make it livable enough (think Subnautica). They're so far capable of at least: specially-designed glass and metals to create tools and structures to withstand the pressure, gathering energy from hydrothermal vents and brine pools, and collecting rare ore deposits in the ocean floor. The more advanced places are capable of creating simple submersibles and robotics for specific tasks but these are few and far between, and incredibly costly for an average sea-Joe.
With all that out of the way, I was imagining a way for them to make music and what sort of instruments they could use. They still hold on to traditions from their human ancestors, and so tried to replicate things as much as they could with what they have. Obviously there's a world of difference between sound in the air and in the sea. Vibrations are different, speed is different, distance is different, intensity, scales, etc. Which is why when similar questions are asked, string instruments are usually one of the first to go. Percussion and vocals are typically accepted. But I was wondering, is there a way to engineer a string instrument where it could sound similar in the water as it would on land, or at least be playable? For example, a lyre/harp.
I was actually inspired by the Glass Harp Sponge and wanted the structure to be based on it.
[](https://i.stack.imgur.com/PFgKE.png)
I considered having metal "strings" made of metals found on deep sea floors that could mimic the look and feel of a traditional harp/lyre (and they'd certainly be better than traditional ones). The bulbs on top could act as resonators of the sound. However, I'm still not sure how the overwhelming pressure of the surrounding water would affect the vibrations/sound. Alternatively, I thought it could be struck like a piano's strings via percussion-- perhaps encased in something to help resonate the vibrations much like the piano's casing.
How can I replicate this "harp" as closely as possible, using my merfolk's current technology?
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Compare this video of "[Under the Sea](https://www.youtube.com/watch?v=JRkIuUDAirE)" performed underwater on a piano to a [normal piano cover](https://www.youtube.com/watch?v=1_2XzBC6F4g), especially the first 5 seconds of the song. The former version has these completely dead-quiet moments that the latter does not. What is happening is that the vibrating strings in the underwater piano give all their energy into the environment faster than the normal piano, causing them to stop vibrating sooner. This will be true of anything played underwater compared to the air, simply because water is denser than air.
However, can we really say the piano didn't work underwater? Yes, the strings stop vibrating sooner, but they still vibrated and produced sound. It certainly sounds different, but different does not mean bad. Rather than fighting the muting effect of water, why don't you lean into it? Explore what music sounds like when it is physically impossible to hold a note for longer than a fraction of a second. Perhaps merfolk music is extremely fast, with more notes played per second to make up for notes not lasting as long. Perhaps merfolk music-notation reflects the pitch and volume of sounds, rather than pitch and duration. Perhaps music is viewed as an exclusively group activity because individual instruments are unable to consistently fill a soundscape.
Also, a gas-filled cavity is a great way to amplify sound underwater. Many fish make sounds by vibrating muscles or hitting bones connected to the swim bladder ([1](https://dosits.org/animals/sound-production/how-do-fish-produce-sounds/))([2](https://oceanexplorer.noaa.gov/explorations/05deepcorals/background/acoustic_listening/acoustics.html)). Many underwater speakers have air-cavities for similar reasons. A 'harp' based on this would look like a guitar, where the body was sealed and filled with air.
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String instruments would work fine, albeit with a more muted sound, as would many percussion instruments.
You might have seen the Danish orchestra who started doing underwater performances, if not, check out their videos, e.g. [this one](https://www.youtube.com/watch?v=0Gb5uetWE3w)
As L. Dutch says, the high density of water will means damping will be higher, so you probably want **thicker and heavier strings** than a typical "air harp" to get any sustain whatsoever. The sound of plucked guitar strings under water is similar to that produced when a guitarist mutes the strings with the back of the palm of their plucking hand. In the video I linked they demonstrate a violin, which is a good example that **bowed string instruments are fine**. Like Vesper sais: the bow constantly adds energy to the string instead of just adding it momentarily as when the string is pluck.
I would refer to the instrument you describe at the end as a **lamellophone**(see [wikipedia article](https://en.wikipedia.org/wiki/Lamellophone)) rather than a string instrument. (Some people might argue it's an [idiophone](https://en.wikipedia.org/wiki/Idiophone), but I'd argue they are probably wrong, depending on how the sound would be transfered to the surrounding water.) They work fine under water as well (see [video](https://www.youtube.com/watch?v=xYJq5_kxwug)) but have similar issues with shortened sustain. Your rods seem rather long and heavy, so they should be fine. They might need to be mounted on some structure with a larger surface to better transfer the vibrations to the water, but that depends on their precise construction.
If you would combine these ideas, you could possibly end upp with an under-water version of a **[nail violin](https://en.wikipedia.org/wiki/Nail_violin)**, a bowed instrument which was the first thing I thought of when I saw your sponge thing. If you would curve the arms around, so all of them point to the left or to the right, you could use a bow to stroke them induvidually.
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Your problem is not the pressure, but the density.
As a 0th order approximation, considering that water is 1000 times denser than air (and water pressure doesn't affect water density appreciably), it will damp vibrations 1000 times more effectively, meaning that obtaining any sound longer than a TAK will become difficult if not impossible.
What can be tried is to let the thing vibrating, and thus producing the sound, in a chamber filled with air, and then have that chamber acoustically coupled with the surrounding water via some mean of impedance matching, which incidentally is how water mammals manage to produce sounds underwater.
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If you want to have something that is played similarly to the harp, I suggest an underwater variation of a [hydraulophone](https://en.wikipedia.org/wiki/Hydraulophone) — basically a pipe organ that uses water rather than air. Here's what I have in mind:
* There's some kind of pump that maintains a pressure differential between the inside of the pipes and the outside. Since it is the differential rather than the absolute pressure that matters, this ought to work even if you are very deep underwater (depending on how you drive the pump, of course).
* Each pipe corresponds to one note. You play the note by touching a key on the pipe that alters the flow of water through the pipe.
* The key mechanism should be spring-loaded and keep the sound flowing for a period of time before cutting it off (much as some doors close slowly at a constant rate after being opened). Potential variations:
+ Perhaps there is also a percussive element that strikes the pipe, causing it to vibrate more loudly (like a bell) for an instant when you activate the pipe. This extra volume will very quickly be damped down by the water, so you need the water flowing through the pipe for the (softer) sustained sound. [CAVEAT: I don't know how feasible it would be to make the percussive sound both nice and the same pitch as the water-driven sound.]
+ Perhaps you can make the sustained note last for a shorter or longer period of time depending on how far you move the key. One skill of an advanced musician is being able to play an arpeggio and have all the notes of the cord end at the same instant.
+ Perhaps there is a separate key on a pipe you can press to stop the sound. Or even a key that stops the sound in all the pipes at once.
I imagine the result would look something like your Glass Harp Sponge but with something like a clarinet key attached to each pipe. Larger, less-transportable versions would include more pipes, larger pipes for lower pitches, and probably an organ console (or else require multiple players, like a handbell choir).
The point of this whole setup is that the flowing water allows for sustained sound, which is infeasible underwater unless you have some continued source of energy (such as a continuous flow of water or air, or for stringed instruments a bow).
Note that the control mechanisms described here would *probably* only arise if someone were deliberately trying to reproduce the experience of playing a harp. If the instrument evolved naturally in a sea-dwelling species, you'd probably get something more like an organ console (with perhaps an exotic keyboard) in which a note was sustained only as long as it was held down. Organ stops would allow you to add the bell or chime sounds to make it easier to identify the beginning of a note. I'm basing this on the assumption that real-world pipe organ control mechanisms are probably the most practical way to control instruments like this.
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[](https://i.stack.imgur.com/IFDCM.jpg)
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> So the human body temperature is much lower than that of the cave environment. That means that the air you're breathing is hotter than the inside of your lungs. In these conditions, **the humidity from the hot air will start condensing in your lungs.**
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In the Naica Crystal Cave, conditions are such that, without also having breathing apparatus, a human will eventually die due to the high humidity because the water vapour condenses in the lungs.
I am wondering how to have an atmosphere that would cause a human to eventually develop pulmonary edema due to high water vapour and humidity.
Two questions:
* Is there any way I can have this effect happen without people dying from heat stroke far quicker?
* What kind of gravity, atmospheric pressure, density, content, etc. would be the best way to replicate this effect and have humans die due to the water vapour condensing in their lungs? Assume that all other gases in this atmosphere are breathable and at a suitable partial pressure.
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The key is in the vapor pressure of water. If you can lower the vapor pressure (by lowering the temperature) to below the partial pressure of water vapor in the air, then water will condense out of the air and form a liquid.
For water to condense inside a human's lungs, then the partial pressure of water vapor in the air must be greater than the vapor pressure of water at the temperature of a human's lungs.
Human body temperature is about [37˚C](https://en.wikipedia.org/wiki/Human_body_temperature). Wikipedia has a nice table showing the [vapor pressure of water](https://en.wikipedia.org/wiki/Vapour_pressure_of_water) at various temperatures; and for a more precise number (since 37˚C falls between entries on Wikipedia's table) we can ask WolframAlpha, which reports [0.062 atmospheres](https://www.wolframalpha.com/input?i=vapor%20pressure%20of%20water%20at%20human%20body%20temperature).
So, you'll need to have more than 0.062 atm of water vapor in the air, and in order for all that water to be in the gas phase (and not already condensing on the walls and floor), the temperature will need to be higher than 37˚C.
Which are pretty much exactly describes conditions in Naica Crystal Cave.
Humans won't be able to shed heat by sweating (in fact, water will condense on their skin as well, heating them up even faster), so they'll develop heatstroke pretty quickly without using some technology to keep themselves cool.
But can the pulmonary edema set in before the heatstroke? I have no idea.
You may be able to make pulmonary edema occur faster by increasing the temperature and partial pressure even farther above 37˚C and 0.062 atm. This will speed up the heatstroke as well, but it'll still take some time for that heat to spread throughout the mass of the body, so the heatstroke may not speed up as much... maybe. I'm guessing wildly here. I'm not a doctor.
But, at some point, your ill-fated explorers will basically be walking into an autoclave, at which point they may die to some other condition entirely, which I do not have the words to name.
Is there some sweet spot in the middle where pulmonary edema wins? Maybe. I don't even know where to look that up.
What I can say is that gravity, density, and partial pressures of gases other than water aren't likely to make any difference at all for your question. A lack of oxygen, say, or the presence of any number of toxic gases may cause death before either heatstroke or pulmonary edema; but barring effects like that, gases other than water vapor can fairly safely be ignored.
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Highly unlikely.
Wikipedia's handy [water vapour pressure](https://en.m.wikipedia.org/wiki/Vapour_pressure_of_water) page says that at 50 °C, water's vapour pressure is about 12.3 kilopascals. A typical breath moves about half a liter of air through the lungs (the [tidal volume](https://en.m.wikipedia.org/wiki/Tidal_volume)). Using the [ideal gas law](https://en.m.wikipedia.org/wiki/Ideal_gas_law) and water's molecular weight (18 g/mol) and density (1 mL/g), this gets you at most 0.04 mL of liquid water condensing out of each breath ([Google Calculator](https://www.google.com/search?q=(12.3%20kPa%20*%200.5%20litre)%2F(8.314%20J%2F(mol*kelvin)%20*%20(273%2B50)%20kelvin)%20*%2018%20g%2Fmol%20*%201%20mL%2Fg)) -- this ignores both the time that full condensation would take and the water vapour that would remain in air at a lower temperature.
At 20-30 breaths a minute, that would get you about 1 mL of condensate per minute (if not much less), and over an hour that would give 60 mL of condensate. I'm sure it would be unpleasant, but given this is only one tenth of a breath's volume and 1 percent of usual [total lung capacity](https://en.m.wikipedia.org/wiki/Lung_volumes), I don't think the pulmonary condensation will be an acute medical emergency -- not in comparison to the heatstroke one would suffer being out at 50 °C in 100% relative humidity for an hour.
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None of these variables are relevant because water's vapour pressure is largely independent of other gases ([Dalton's Law](https://en.m.wikipedia.org/wiki/Dalton%27s_law)). Indeed, if there were some handwavium gas that kept water in the atmosphere at a higher vapour pressure, it would, well, *keep water in the atmosphere at a higher vapour pressure* and hinder condensation in your poor characters' lungs.
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As the other answers point out, it's effectively impossible to conjure a situation in which a person inhales humid air and dies from pulmonary edema before they would die to heat stroke or some other immediate condition.
I would, however, propose a frame challenge. Instead of restricting yourself to water vapor, you could also consider water mist. Misted water can remain airborne for a short period of time before settling and can be easily inhaled at much colder temperatures than water vapor would require to condensate. Given enough time, a person could inhale enough mist that it would lead to pulmonary edema.
Granted, it would probably take a while, and the person in question would detect the warning signs long before it happens (like constantly coughing, for instance). A cave environment with such a scenario would also likely have a host of other problems for a spelunker as well; if there is mist being sprayed all over the place, erosion would be a significant factor in the cave's traversability and a thick blanket of slippery moss would cover every surface. But it's possible.
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In fact, the inhaled air does not go directly in the lungs. If first goes through the nose and most of .the temperature change is expected to happen there. If you think about what happens in a hammam (temperature between 40 and 50°C and water vapour close to 100%), you just have to breathe slowly. If you try to breath too fast, it becomes uncomfortable because you feel burned deeply (down to the throat) but if you manage to keep calm and breath slowly you do not feel burned inside. I assume that the water vapor condenses in the nose and the upper respiratory tract, but very few liquid should reach the lung.
As said by others, if the temperature is higher, the water vapor in the lung will be a minor question, because you will have no way to control the body temperature and above 40°C you will feel really bad...
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> I am wondering how to have an atmosphere that would cause a human to eventually develop pulmonary edema due to high water vapour and humidity.
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I may be going on a tangent here, but this is easily achieved when you have intelligent and resourceful humans... as long as they don't know how to properly manage excess heat.
[Serge'sanswer](https://worldbuilding.stackexchange.com/a/250521/21222) has a good example of something that can happen if you don't know how to behave in a Moroccan bath. Now check [this article from the US National Library of Medicine](https://pubmed.ncbi.nlm.nih.gov/12943045/):
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> The military physician diagnosed a 19-year-old military recruit from an elite unit to have exertional heat stroke. Immediate treatment in the field with rapid ice water cooling and vigorous fluid administration resulted in pulmonary edema.
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Dude's peers were just trying to help, but they almost killed their friend faster instead. But I expect people who live in hot areas to know better.
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I also found [this in MedScape](https://emedicine.medscape.com/article/166320-treatment?form=fpf#d7):
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> Pulmonary edema is a common complication of heat stroke and may be due to a number of factors, including fluid overload from aggressive rehydration, renal failure, congestive heart failure, and ARDS.
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You know what? The [Urban Heat Island Effect](https://en.m.wikipedia.org/wiki/Urban_heat_island) is a thing. Some cities just have places that get freakingly hottter than the average temperature for the region, due to poor urban planning. And the modern, western urban dweller is a creature that is addicted to table salt, leading to renal and coronary problems being quite popular in developed countries. [Going back to the National Library of Medicine](https://www.ncbi.nlm.nih.gov/books/NBK557611/):
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> More than 1 million patients are admitted each year with a diagnosis of pulmonary edema secondary to cardiac causes (heart failure).[4] An estimated 190,000 patients are diagnosed with acute lung injury each year. About 1.5 to 3.5 cases/100,000 population are diagnosed with ARDS.
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That article is from April 2023. One million people there is 1 in every 331 americans.
Now that doesn't mean every single case of pulmonary edema followed a heat stroke, [but according to USA Facts](https://usafacts.org/articles/how-many-people-die-from-extreme-heat-in-the-us/) (disclaimer, I don't know how reputable a source this is, but let's assume it's accurate):
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That's almost one in five americans. Now let's elaborate:
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> In 2023, Americans are increasingly grappling with prolonged heat waves — sometimes dubbed “heat domes” or “heat islands” by the Environmental Protection Agency — even in areas accustomed to particularly high heat. Phoenix, Arizona, for example, registered an average daily high temperature of 114.7 degrees Fahrenheit in July.
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114.7 F is about 46 Celsius.
And finally:
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So I am not saying that those million edemas were majoritarily caused by heat, but I believe there is good cause here to justify funding research to find the degree of correlation (if this hasn't been done already, but I couldn't find anything quickly). But you know what? It may be that the conditions you need for pulmonary edemas due to heat are found on most big cities nowadays.
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How realistic would it be for the son of an emperor to go to some college town (think something like Oxenfurth from *The Witcher*) with a false identity? He pretends that he is some kind of lower-rank aristocrat in order to not get special treatment, and also for safety reasons.
I think it would be more likely that the son of the emperor has private tutors. Although he is not the heir, he is like the seventh child so it could be plausible. Let's say in order to prepare him to be some kind of educational minister, it would be best to go through the educational system.
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## Depends on the exact time, and society.
You tagged this [medieval](/questions/tagged/medieval "show questions tagged 'medieval'"). For most of the medieval time, colleges and universities where not quite what we think of today, and neither was society. In a way, a change in the mode of learning is *one* of the things which sets the medieval world apart from the modern.
There would certainly be tutors for the first years, but **university** could start at age 15 or 16, what we would today call college or even high school age. Teaching a "spare prince" the [seven liberal arts](https://en.wikipedia.org/wiki/Liberal_arts_education#History) might well have been a plan to set him up for an administrative (or religious?) position, reinforcing the rule of an older sibling as a trustworthy advisor.
**No newspapers and no photographs**
The [medieval](/questions/tagged/medieval "show questions tagged 'medieval'") period had no printed books or newspapers. The printing press [made a great difference](https://This%20is%20not%20my%20trueborn%20heir.) in this regard. The art styles also made it harder to recognize individuals. So a junior prince who did clain a different name would have had a good chance not to be recognized.
I agree with [David R](https://worldbuilding.stackexchange.com/questions/233938/how-real-is-that-the-son-of-the-emperor-goes-on-the-college-undercover/233942#233942) about the problems of disguising class, but this could be handled by claiming to the the [illegitimate offspring](https://en.wikipedia.org/wiki/Legitimacy_(family_law)#Law) of some other, senior noble. With the support of that noble, the story might stick. *"Please take this young man into your university. He is not my legitimate heir. Here is the tuition. Please find some room for his servants, who wear my livery."*
**But this could backfire.**
The lack of *paparazzi* and photographs could become a problem later on, when it becomes time for the prince to act as a prince. You called it a 7th son, but mortality was high. The prince might well get a fairly senior place in the line of succession, and get called to act as a regent for the minor children of a dead brother, say. In that case, credible witnesses who swear that they went to college with him could be a problem. Some of the old pals might have gone on to study theology, become senior clerics ...
**The Russian Precedent**
[Peter the Great](https://en.wikipedia.org/wiki/Grand_Embassy_of_Peter_the_Great) traveled incognito through western Europe as the junior member of a delegation ostensibly led by someone else. But that incognito did not hold.
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Human children go through stages in their development. Early on, they are bonded to their parents. But teen years are where they break free from parents and bond with a tribe. In royalty, that is a very difficult challenge (see the difficulties that the British royalty had with Prince Harry).
While a royal family might send their son to a university for that process, the traditional method is to send him to a baron to foster - to be a squire in that household. Why? Because someone who has grown up with privilege has quite a number of unthinking habits that other people just don't have and who recoil from someone who has them. Putting him with a baron will keep him among those with privilege and those habits won't cause social problems. Also, in this way, the son will have formed friendships with those with whom he will go into battle.
While an idealistic son might want to try to go "undercover", the unconscious thought processes are so different as to make him stand out. As a modern example, read "Black like me" where a white journalist attempted to go "undercover" as a black man in the deep south and had to be educated about how differently he had to think and behave. His unconscious patterns of behavior as a white man would have gotten him killed as a black man in the deep south back then.
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**College undercover, with security also undercover.**
Your 7th son (of a 7th son!) goes incognito to school for the reasons you lay out. He plays the role of a real person whom he somewhat resembles; an actual lower rank aristocrat his age. The real boy is offered a position as a junior officer stationed abroad by the Emperor. The real boy is dissolute and somewhat of a layabout but neither he nor his family are fools.
The risk though is that the Emperors son is found out by persons who wish to hold him for ransom. With him in school are very capable persons charged with attending school and watching the Emperor's son.
The Emperors son does not know about these guardians. One of them is actually a bully towards him; deep cover. The son finds out in the course of the story. The bully guardian thinks that besides him there is another one at the school but does not know who it is. As it turns out she works for the school and is not a student.
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/I think it would be more likely that the son of the emperor has private tutors/
You are right. And it is more likely that the firstborn grows up to be Emperor. The fact that the Emperor is himself a seventh son means his own track has been unconventional. As is the Emperor himself.
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I believe that in Shakespeare's play *Hamlet* (c.1599-1601) Prince Hamlet of Denmark has travellrd to Germany for education.
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> However, a case has been made[4] that at an early stage in Hamlet—with its apparent history of multiple revisions—Hamlet was presented as a sixteen-year-old. Several pieces of evidence support this view. Hamlet attends the University of Wittenberg, and members of the royalty and nobility (Elizabethan or medieval Danish) did not attend university at age 30. Additionally, a 30-year-old Prince Hamlet would clearly have been of ruling age. Given his great popularity (mentioned by Claudius), this would raise the question of why it was not he, rather than his uncle, who was elected to succeed to the throne upon the death of King Hamlet.
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[https://en.wikipedia.org/wiki/Prince\_Hamlet][1]
So by Shakespeare's time some members of royalty and nobility did attend universisties. And it ispossible that some members of royalty might have begun going to niversities some time before whatever date you choose for theend of the middle ages.
<https://en.wikipedia.org/wiki/Prince_Hamlet>
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In medievalish setting, normally members of a royal family would be illiterate or at most, know how to read and write, taught by tutors. Book learning was the field of clerks, whom they would have at hand to take dictation and read letters,.
This increased through the era and into modern times,but it was taught by tutors. Remember the current Prince of Wales is the first British royal to hold a degree.
Also an educational minister is a modern thing and not early modern. If a member of a royal or noble family went to college in medieval times, the safe assumption was that he was meant for the Church.
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**The Emperor's son is a Bastard**
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If you want to explain why he doesn't have private tutors, you are best making him an illegitimate child. This is a classic trope. He is a distant heir to the Golden Elephant Throne but no one knows. Maybe he doesn't know himself.
His mother is not the empress. He has his mother's last name. Illegitimate children are frowned upon. The emperor wants to "get rid of" the son by packing him away to a boarding school. The mother is happy since she could not afford this school anyway.
The relationship between the Emperor and the son can be whatever you want. He is the Emperor after all.
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I'm writing a cyberpunk book where people can regain their vision by connecting an artifical eye and the optic nerve would be replaced by a electrode, is it possible? Ignoring the rejection and possible infections, could an electrode transmit information as good and as fast as an optic nerve?
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# Yes
*Now for the ugly details.*
You say "electrode." However, an "electrode" is anything used to conduct electricity. That can be a superconducting chunk of niobium to a better-than-average-grade of sand to graphite to a wonderful bit of gold. Why is this important?
* Because a superconductor has perfect conductivity and is therefore a LOT faster than optic nerve transmission—but the temperatures required make it useless for cyberpunk.
* Because a semiconductor (like silicon or germanium) are only as fast or slower than the optic nerve.
* Because poor conductors, like graphite and tungsten, will pass electricity but only after generating a boat load of heat.
* Because the obvious choice is a metal conductor that will always be faster. Except...
**And then there are details you don't want to deal with.**
*Termination*
Connecting an artificial anything to the human body is non-trivial. Connecting something that must convey information is even worse. The connection between your electrode and the optic nerve will have problems. In the electronics world, we call this *termination.*
Whenever you try to connect one electrical conducting object to another electrical conducting object, you have the problem of termination (the need to match the impedance1 of the two conductors to ensure maximum power transfer and minimum corruption of the information). Think of it this way. If you have a two-inch pipe carrying water at 20PSI and simply connect it to a one-inch pipe. What happens when the water hits it? All kinds of cool things! And electrically, it's even worse. You can actually *degrade the signal you're trying to transmit* because you failed to terminate correctly.
*Corrosion*
Another problem is corrosion. In the real world, when two different metals are brought together you risk what's called *galvanic corrosion.* In other words, the electrical properties of the two metals actually act to *cause* corrosion. Now, we could solve this problem in the biological world (where you have base goos and acidic goos and other kinds of goo that simply don't want the metal anywhere near it) by using surgical stainless steel, which would resist corrosion.
But the conductivity of surgical steel is about 1/40th of the conductivity of copper. It simply stinks as an electrical conductor.
*Insulation*
Another problem, and it's not a trivial problem, is that there isn't just one optic nerve. What we call the "optic nerve" is actually a bundle of nerves. A LOT of nerves. And that means your conductor must have as many wires as there are nerves—and those wires must be insulated one from another or all kinds of messy things like *crosstalk* (the coupling of energy from one transmission line to another in a way that corrupts the information on either line) and *shorts* (where the user suddenly sees the optical equivalent of a blue screen of death because all the nerves are being fed the same information). Insulating wires that thin is no small thing—but that's the beauty of fiction!
*Magnetism*
And I'll add one more even though it's a bit of a stretch (OK, a long stretch) to believe it's a significant problem. You don't want to use an electrode that's *magnetic.* Most good conductors aren't magnetic. But it's worth noting that the human body is remarkably resistant to magnetism. That electrode might not be. Neither might the artificial eye. One would hate to see the outcome of a knife fight to which your opponent brought not a gun, but a magnet. I'm just sayin'.
**Recommendation: Avoid the pain of including too many details**
# Yes
You can believably use an "electrode" to connect an artificial eye to the optic nerve in a cyberpunk setting.
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1‚ÄÉ*You might have already heard of resistance. A superconductor has zero resistance to the flow of electricity. Resistance impedes the flow of electricity, usually by virtue of converting some of it to heat. Did you catch that word, "impedes?" Resistance is passive. "Reactance" is active (capacitance and inductance). The two together (resistance + reactance) are called "impedance," referring to all possible electrical mechanisms that can slow the march of electrons. Don't worry about this. Just know that termination isn't as simple as I'm describing in this answer.*
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#### With 2020's tech, it is actually around 8 times as fast.
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We start with a huge caveat. We do not have technology to convert digital into neural signals with the level of reliability required for video input in a resolution/depth of color compatible with the human eye, as @UVphoton points in his comment.
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Currently existing product in category bionic eye.
[Argus II retinal prosthesis system](https://secondsight.com/discover-argus/). Has approval of FDA.
It has helped some people restore some visual perception.
Is it full vision replacement? Very much no. Current tech has too few sensors an article mentioned trying to increase it to 150 sensors where million is the target.
Could such technologies eventually be? Probably.
Compactness and energy are the issues, not speed.
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Of the general options that exist in terms of hypothetical space launch systems, what is the most plausible option for a relatively near future SF setting? The focus here is on Earth to LEO, as the level of space development this cheaper access would imply also lowers costs by giving refueling infrastructure in orbit.
The few obvious ones that come to mind are:
Space elevators would be the best option overall in terms of lowering costs, but there is the question about whether we could actually pull this off in a practical sense. Besides the question of finding a strong enough material, a failure would be catastrophic in scope. It would also likely require literally perfect forecasting of lightning strikes, as the most likely material is carbon nanotubes that would be very conductive to electricity.
Laser launch to orbit works similarly to a space elevator in terms of offloading the mass of the fuel, but it trades the problems. While it would not require borderline impossible physics, it would require utterly massive energy storage or production at the launch site. It would also be an extremely potent weapon system that would make other nations that the owner nervous and possibly blind anyone looking at the launch.
Improving the fuel via metallic hydrogen is also a possibility, as probably the most high energy and high thrust rocket fuel that doesn't involve setting off nuclear weapons. It isn't the same level of extreme savings as something like a space elevator, but it could potentially lead to savings as it would allow proper mature SSTO designs with large payloads to develop. If fusion rockets could produce enough thrust to get off the ground, they would be also be an excellent option in roughly the same category, but that is not likely.
Reusable designs and their descendants. This is obviously what is happening already in terms of design, but even the most optimistic(and probably more than a little unrealistic) projections would not approach even the conservative projections of the more advanced concepts. One other possible related approach is that of the SABRE(or RAPIER for KSP players) engine in which it uses a ramjet/rocket hybrid, if that can ever be made to work.
Of these or any others I'm not familiar with, what is the most plausible general solution to give significantly cheaper access to orbit within the next century?
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## Pick one or more to satisfy your story telling needs.
As mentioned, the [Non-rocket spacelaunch](https://en.wikipedia.org/wiki/Non-rocket_spacelaunch) Wikipedia article gives a nice overview of proposed cheaper space launch systems.
To that I will also add, Big Dumb Boosters. You've perhaps heard of the [SpaceX BFR](https://en.wikipedia.org/wiki/SpaceX_Starship_development_history#Big_Falcon_Rocket) - this is an example of the fact of the square-cube law effect on rocket launch systems (resulting in a higher fuel / weight ratio) as rockets are made larger. There are diminishing returns on bigger rockets, so you won't be launching small mountains this way. The [Sea Dragon](https://en.wikipedia.org/wiki/Sea_Dragon_(rocket)) was the largest booster ever considered at the time and although dated, still a valid example design.
Many of the systems are, or can be made complimentary. e.g., combine a rail-gun system like Star Tram to improve the initial stage efficiency and something else to help pull your craft into orbit such as a skyhook system.
In real life, if I had many billions to spare for such, I would not be looking at a space elevator as my solution because I would want something that I was certain could be achieved - and we still don't know whether it is possible to actually build a space elevator on Earth, though I am certain other system could be built - no new science or technology breakthroughs required. Room temperature superconductors could make your rail-gun more desirable, but you don't **have to have** them for the plan to work.
You can also combine rockets with most of these systems., e.g., rail gun for a good head start with rockets to complete orbital insertion, or perhaps rail gun, then rockets to get it the rest of the to your sky hook.
Plausibility does not require certainty though. It's all about what makes your story work.
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# Skyhook!
Ok, I don't know if it's the *most* plausible, but until one of these technologies is realized nobody will know which one was most plausible. And I like skyhooks, so I'm going to roll with it.
The basic idea of a skyhook is to put a tether into orbit with a hook on one end and a weight on the other, then set it spinning. The hook end dips down into the very uppermost reaches of the atmosphere periodically, where ships can attach to it and get flung up into orbit. The physics of it is actually really simple, but of course there are a few problems (all surmountable).
First, materials. Unlike a space elevator, we wouldn't actually need any breakthrough advances in materials science to make a skyhook work. Most skyhook designs would work fine with existing materials, although production of these high-strength materials would need to be scaled up and made economical. This is actually one of the easier challenges with the skyhook design.
Another easy problem is conservation of momentum. Essentially, every time you grab and launch a craft into orbit, you're leeching a bit of energy / momentum from the hook. There are two ways to solve this. The first is to equip the skyhook with small chemical or ion rockets that would periodically boost and adjust its orbit, keeping it from falling into the atmosphere. These would need periodic refueling, and in general are inferior to the second solution: send stuff back down. A skyhook works in both directions, and if you catch things out of orbit and lower them back to Earth with the skyhook you'll be recovering energy / momentum from them, keeping the whole skyhook up in the sky for "free". Some smallish amount of stationkeeping would probably be required, but overall this is a much better option than just reboosting after every launch.
The hardest problem to solve with a skyhook is the problem of spacecraft needing to actually *catch* the hook. At its lowest point it will still be moving quite fast relative to the ground, and that lowest point is still in the upper atmosphere. So you'll need specialized ships designed to accelerate up to the speed of the hook, and these craft need to be able to *find* it and latch on. This is probably solvable with some combination of computer guidance, careful scheduling, and assistance from the hook itself (the [Kurzgesagt video](https://www.youtube.com/watch?v=dqwpQarrDwk) on the subject suggests having drones on the hook end of the skyhook to assist in catching spacecraft; the linked video is a great resource, by the way, but do note that it's focused on using skyhooks to facilitate interplanetary travel rather than travel to LEO).
[Answer]
**Rockoons!**
[](https://i.stack.imgur.com/an8aD.png)
<https://www.semanticscholar.org/paper/Development-of-a-Rockoon-Launch-Platform-and-a-Fuel-Johnson-Roberson/aa576b73f3b9ebe1f1201b8d7119e4707e9d595c>
10. Float up above sticky grabby draggy gas with balloon and attached rocket.
11. Launch rocket!
12. Pump floaty stuff into cylinder so balloon descends.
13. Get new rocket.
14. GOTO 10.
<https://en.wikipedia.org/wiki/Rockoon>
>
> A rockoon (from rocket and balloon) is a solid fuel sounding rocket
> that, rather than being immediately lit while on the ground, is first
> carried into the upper atmosphere by a gas-filled balloon, then
> separated from the balloon and ignited. This allows the rocket to
> achieve a higher altitude, as the rocket does not have to move under
> power through the lower and thicker layers of the atmosphere.
>
>
>
<https://www.livescience.com/47692-high-altitude-balloons-floating-satellites.html>
>
> High-altitude balloons, some of which can reach altitudes of up to
> 100,000 feet (30,500 meters) or 19 miles (30.6 kilometers), have been
> used to observe weather patterns since at least the early 20th
> century, and NASA has been using these types of balloons to conduct
> scientific experiments for the past 70 years, Crites said...
>
>
> "We think the key is to build a platform to get people exploring up
> there," Crites said. "What we want to see is students and
> entrepreneurs using new applications on this platform and getting
> really creative."
>
>
>
My personal favorite though is the railgun [rockeloonannon](https://www.halfbakery.com/idea/Rockeloonannon#1203899193) in which a railgun on a high altitude floating platform fires the rocket up to orbital altitude and the rocket then attains the lateral velocity to stay in orbit. Rock Rock, Rockeloonannon!
[Answer]
#### Space Fountains and Launch Loops
A [space fountain](https://en.wikipedia.org/wiki/Space_fountain) is essentially a space elevator that could work with current materials. Instead of relying on material strength, the space fountain is supported by the active motion of iron slugs cycling through it, similar to a stream of water arcing up from a hose.
A [launch loop](https://en.wikipedia.org/wiki/Launch_loop) is a possibly more practical version of space fountain that doesn't try to go straight up. Instead it extends horizontally for hundreds of miles, providing a runway 50 miles up from which to launch ships, and acting like an enormous aircraft carrier catapult. A big advantage is that the iron slugs can have more room to turn around when they touch earth, so you can use many miles of electromagnets to gradually turn them. A disadvantage is that the launch loop is more vulnerable to ground attacks, because it covers more territory and enough damage at any point could destroy it.
[Answer]
Question as posed: What is the most *plausible* way to *lower* costs to orbit?
**Just wait.**
No stipulations have been given as to how much the costs must lower, only what's most plausible. However, it's plausible (even likely) that we'll see a *substantial* reduction in launch costs in our lifetime, through three mechanisms...
1. Private sector companies replacing inefficient government monopolies.
2. Adoption of greener energy lowering the price of crude oil, and thus, kerosene.
3. Economy of scale, in technology and production.
As noted in the question, private companies have succeeded in developing reuseable rockets, with very considerable cost savings. They're also driven much more to bring down costs, as decreasing costs result in increasing profits, not decreasing budgets. What have we seen so far? Private companies have brought the cost of launch into orbit from 18,500 USD / kg down to 2,720 USD / kg, an *85%* reduction in cost. (<https://theconversation.com/how-spacex-lowered-costs-and-reduced-barriers-to-space-112586>) As these companies are driven by profit and the future of society (in Musk's case), they have reason to continue to lower these costs as far as they can.
Yet, even as these companies burn mind-boggling amounts of fuel to get into orbit, we can expect the cost of that fuel to go down in the next century, due to crude oil's replacement with electricity. Even if only cars go to (renewably generated) electric, it's reasonable to expect the cost of crude oil to drop dramatically, and with it, fuels like RP-1 that help with launch. Rocket launches may be the one place that hydrocarbons make the most sense, for their energy density (both in MJ/kg and MJ/L).
Finally, as space exploration becomes more common, economy of scale will start to kick in. When private companies find designs that work very well, they can move from essentially experimental launches to mass production, with huge associated cost savings. The bigger private companies are already playing with this idea, but have a long ways to go in the next few decades.
How long will all this take? At the current rate, and seeing as two of the richest people in history are vying to accomplish these very goals, we're looking at a scale of decades, if even that.
This may not be a particularly out-there answer, but that also makes it the most *plausible*, in my humble opinion. And there's no reason to expect that private companies, mass-producing highly reusable rockets to launch with likely ever-cheapening fuel, will have any trouble reducing the costs of launch to orbit.
All this takes is time. So, in short... **just wait.**
[Answer]
**Ecuadorian Railgun**
Pick a tall mountain near the Equator. Build a railgun up the side of the mountain. Put a nuclear power station and a *big* bank of capacitors nearby to produce the phenomenal surge required to energize all those magnets at once. And *shoot* your cargo into orbit.
Of course, the cargo must be hardy enough to withstand a few dozen Gs. Squishy humans must continue to ride oversized firecrackers into orbit.
You will need a space-tugs at apogee to prevent the cargo from re-entering, of course. Your railgun capacity will be limited by the number of tugs, by the number of launches that your power plant can support, and by the number of UN-employed inspectors ensuring that a "mistake" doesn't blast a city. So the cafeteria at the railgun base needs to be impressively large, too.
[Answer]
**Linear Induction Launcher**
A much more feasible alternative to a railgun, the Linear Induction Launcher not only has no fundamental speed limit, it also levitates the armature for a relatively frictionless (aside from air resistance) journey down the barrel.
The operating principle is to axially stack many coils of wire to creat a barrel. Each subsequent coil will have fewer and fewer turns. When pulsed in an accelerating sequence, a traveling (and accelerating) magnetic wave will be created that, by the principle of induction, will create a force in the same direction of travel on any conductive object within the barrel.
]
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